1水平分庫

最近在做一個IM系統(tǒng)，之前的舊系統(tǒng)沒有考慮到用戶量會增長得這么龐大，導致現(xiàn)在數(shù)據(jù)庫性能瓶頸非常嚴重，迫切需要分庫，用于減少每個庫的用戶數(shù)量，進而分攤負載，最終達到數(shù)據(jù)庫橫向擴展的目的。

數(shù)據(jù)庫水平分庫是以用戶Id為分庫的依據(jù)，同一個用戶的所有數(shù)據(jù)都在同一個庫上，每個庫有著相同的表結(jié)構(gòu)。為了實現(xiàn)開發(fā)人員來說對數(shù)據(jù)庫的透明訪問，分庫框架需要解決二個問題：
1、 方法參數(shù)中有用戶id的數(shù)據(jù)的新增，查詢及修改
2、 方法參數(shù)中無用戶id的數(shù)據(jù)的查詢

2用戶id

把用戶名和密碼所在的表定義為用戶表，用戶id即是用戶表中的惟一性標識的整形值，如果用戶的用戶名只有一種方式，那么id可以是用戶名的hash值，此時用戶表也是分庫的；如果用戶的用戶名有多種方式，比如允許用戶使用email登陸，也允許用戶使用手機號碼登陸，那么用戶id應(yīng)該是用戶表中的遞增字段值,此時用戶表應(yīng)該是不分庫的，這時可以把用戶表獨立為另一個庫，稱之為認證庫。我們的項目應(yīng)用是屬于后者。

1 3 解決方案

3.1    說明

簡單服務(wù)即為DAO,每個domain都對應(yīng)一個簡單服務(wù)，簡單服務(wù)之間不允許互相依賴；復雜服務(wù)可以依賴多個簡單服務(wù)，但不能直接訪問數(shù)據(jù)庫，復雜服務(wù)對數(shù)據(jù)庫的操作必須通過單簡單服務(wù)。

使用hibernate作為訪問數(shù)據(jù)庫的中間層，結(jié)合Spring的Aop攔截方法，簡單服務(wù)代理與簡單服務(wù)實現(xiàn)相同的接口，一個簡單服務(wù)對應(yīng)二個實例，一個引用動態(tài)獲取數(shù)據(jù)庫連接的sessionFactory，另一個引用Hibernate Shards的sessionFactory

3.2    方法參數(shù)中有用戶Id

Spring Aop攔截簡單服務(wù)代理的所有方法，如果方法的第一個參數(shù)為userid，則將userid

放到當前線程中，并選擇引用動態(tài)獲取數(shù)據(jù)庫連接的sessionFactory的簡單服務(wù)實例，在獲取數(shù)據(jù)庫連接時根據(jù)當前線程的userid選擇相應(yīng)連接，流程如下：

3.3    方法參數(shù)中無用戶Id

Spring Aop攔截簡單服務(wù)代理的所有方法，如果方法的第一個參數(shù)為非userid，選擇引用Hibernate Shards的sessionFactory的簡單服務(wù)實例，遍歷所有數(shù)據(jù)庫，并返回匯總后的數(shù)據(jù)。這種情況下只允許讀，不允許寫。流程如下：

1  4實現(xiàn)

4.1    簡單服務(wù)代理

對每個簡單服務(wù)用jdk動態(tài)代理生成一個代理對像，復雜服務(wù)依賴代理對像。

4.2    實例化

在簡單服務(wù)類上標注@DetachDbService，則會產(chǎn)生三個實例(框架實現(xiàn))：

1.       簡單服務(wù)代理實例

2.       引用動態(tài)獲取數(shù)據(jù)庫連接的sessionFactory的簡單服務(wù)實例

3.       引用Hibernate Shards的sessionFactory簡單服務(wù)實例

4.3    方法參數(shù)

如果是到某個庫獲取數(shù)據(jù)，則第一個參數(shù)必須為Long或者UseridAble類型，用于獲取userid

4.4    userid與數(shù)據(jù)庫關(guān)系

總的來說，取模是最優(yōu)方案，但是考慮到服務(wù)器性能可能不一致，而又需要充分利用服務(wù)器資源，所以需要在取模的同時加上權(quán)重。比如現(xiàn)在有二臺數(shù)據(jù)庫，權(quán)重為1：2，那么用戶id先對3取模，0的為第一臺服務(wù)器，1，2的為第二臺服務(wù)器。

4.5精確分頁

由于hibernate shards不能到某個庫或者其中的幾個庫中去查詢，并且它的分頁是先到所有的庫中將所有符合條件的數(shù)據(jù)取回到內(nèi)存中再進行分頁，所以不可能使用它的分頁。      

先用hibernate shards到各個庫上查出符合條件的數(shù)目及數(shù)據(jù)庫標識（標識為查詢表中最小用戶id），返回結(jié)果后對標識進行排序（這樣確保同樣的查詢條件在翻頁的時候能夠以同樣的順序查詢數(shù)據(jù)庫，以達到精確查詢的目的）。根據(jù)這個結(jié)果計算出每個數(shù)據(jù)庫取值的段，然后用動態(tài)數(shù)據(jù)庫連接按之前排好的順序遍歷數(shù)據(jù)庫進行查找，段為0的直接跳過，找滿結(jié)果則返回。

比如現(xiàn)在有3個庫，要查詢所在地為深圳的用戶，通過hibernate shards查得數(shù)據(jù)如下：

這時按用戶最小id排序結(jié)果是DB2,DB1,DB3

假設(shè)每頁10條記錄，

第一頁的數(shù)據(jù)是從DB2中取5條，DB1中取前5條，不需要到DB3去取

第二頁的數(shù)據(jù)是從DB1中取后2條，在DB3中取前8條，不需要到DB1中去取

第三頁數(shù)據(jù)是從DB3中取第9到第18條，不需要到DB1和DB2中去取

… …

缺點：不能精確排序

5關(guān)鍵代碼

Java代碼

1. package com.konceptusa.infinet.annotation;   
2.   
3. import java.lang.annotation.Documented;   
4. import java.lang.annotation.ElementType;   
5. import java.lang.annotation.Retention;   
6. import java.lang.annotation.RetentionPolicy;   
7. import java.lang.annotation.Target;   
8.   
9. import org.springframework.beans.factory.annotation.Autowire;   
10.   
11. /**  
12.  * 簡單服務(wù)類實例化標注  
13.  * @author Jwin  
14.  *  
15.  */  
16. @Retention(RetentionPolicy.RUNTIME)   
17. @Target( { ElementType.TYPE })   
18. @Documented  
19. public @interface DetachDbService   
20. {   
21.     boolean lazy() default false;   
22.     Autowire autoWire() default Autowire.BY_NAME;   
23.     String init() default "";   
24.     String destroy() default "";   
25. }  

package com.konceptusa.infinet.annotation;
import java.lang.annotation.Documented;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
import org.springframework.beans.factory.annotation.Autowire;
/**
* 簡單服務(wù)類實例化標注
* @author Jwin
*
*/
@Retention(RetentionPolicy.RUNTIME)
@Target( { ElementType.TYPE })
@Documented
public @interface DetachDbService
{
boolean lazy() default false;
Autowire autoWire() default Autowire.BY_NAME;
String init() default "";
String destroy() default "";
}

Java代碼

1. package com.konceptusa.infinet.annotation.handler;   
2.   
3. import java.util.ArrayList;   
4. import java.util.List;   
5.   
6. import org.apache.commons.logging.Log;   
7. import org.apache.commons.logging.LogFactory;   
8. import org.springframework.aop.framework.ProxyFactoryBean;   
9. import org.springframework.beans.MutablePropertyValues;   
10. import org.springframework.beans.factory.config.RuntimeBeanReference;   
11. import org.springframework.beans.factory.support.RootBeanDefinition;   
12.   
13. import com.konceptusa.framework.annotation.IllegalConfigException;   
14. import com.konceptusa.framework.annotation.spring.support.AbstractSpringListAnnotationHandler;   
15. import com.konceptusa.framework.annotation.spring.support.SpringAnnotationUtils;   
16. import com.konceptusa.infinet.annotation.DetachDbService;   
17.   
18. /**  
19.  * 向spring中注冊簡單服務(wù)代理實例，引用動態(tài)數(shù)據(jù)庫連結(jié)的簡單服務(wù)實例，引用hibernate shards的簡單服務(wù)實例  
20.  * @author Jwin  
21.  *   
22.  */  
23. public class DetachDbServiceAnnotationHandler extends AbstractSpringListAnnotationHandler<DetachDbService>   
24. {   
25.     private final static String SESSIONFACTORYNAME = "sessionFactory";   
26.     public final static String DYNAMIC_POSTFIX = "Dynamic";   
27.     public final static String SHARDS_POSTFIX = "Shards";   
28.     private final static String DETACHDBINTERCEPTOR = "detachDBInterceptor";   
29.   
30.     private final static Log LOG = LogFactory.getLog(DetachDbServiceAnnotationHandler.class);   
31.   
32.     public Class annotation()   
33.     {   
34.         return DetachDbService.class;   
35.     }   
36.   
37.     @Override  
38.     protected void handle(DetachDbService s, Class target)   
39.     {   
40.         String name = target.getSimpleName();   
41.         if (!name.endsWith("ServiceImpl"))   
42.         {   
43.             throw new IllegalConfigException(target.getName()   
44.                     + " is not a service bean.service bean 's class name must be end with 'ServiceImpl'");   
45.         }   
46.         name = getBeanName(name);   
47.         String dynamicName = name + DYNAMIC_POSTFIX;   
48.         String dynamicSessionFactory = SESSIONFACTORYNAME + DYNAMIC_POSTFIX;   
49.         //生成動態(tài)獲取數(shù)據(jù)庫連接的簡單服務(wù)實例   
50.         createBean(s, target, dynamicName, dynamicSessionFactory);                 
51.         String shardsName = name + SHARDS_POSTFIX;   
52.         String shardsFactory = SESSIONFACTORYNAME + SHARDS_POSTFIX;   
53.         //生成查詢所有數(shù)據(jù)庫的簡單服務(wù)實例   
54.         createBean(s, target, shardsName, shardsFactory);   
55.         //生成簡單服務(wù)代理類   
56.         RootBeanDefinition definition = createBeanDefinition(s, ProxyFactoryBean.class, name);   
57.         MutablePropertyValues mpv = new MutablePropertyValues();   
58.         mpv.addPropertyValue("target", new RuntimeBeanReference(shardsName));   
59.         List<String> interceptorNamesList = new ArrayList<String>();   
60.         interceptorNamesList.add(DETACHDBINTERCEPTOR);   
61.         mpv.addPropertyValue("interceptorNames", interceptorNamesList);   
62.         definition.setPropertyValues(mpv);   
63.         registerBeanDefinition(name, definition);          
64.     }   
65.   
66.     private void createBean(DetachDbService s, Class target, String name, String sessionFactory)   
67.     {   
68.         RootBeanDefinition beanDefinition = createBeanDefinition(s, target, name);   
69.         MutablePropertyValues mpv = new MutablePropertyValues();   
70.         mpv.addPropertyValue(SESSIONFACTORYNAME, new RuntimeBeanReference(sessionFactory));   
71.         beanDefinition.setPropertyValues(mpv);   
72.         registerBeanDefinition(name, beanDefinition);   
73.     }   
74.   
75.     private RootBeanDefinition createBeanDefinition(DetachDbService s, Class target, String name)   
76.     {   
77.         RootBeanDefinition definition = new RootBeanDefinition();   
78.         definition.setAbstract(false);   
79.         definition.setBeanClass(target);   
80.         definition.setSingleton(true);   
81.         definition.setLazyInit(s.lazy());   
82.         definition.setAutowireCandidate(true);   
83.         definition.setAutowireMode(s.autoWire().value());   
84.   
85.         if (!"".equals(s.init()))   
86.         {   
87.             definition.setInitMethodName(s.init().trim());   
88.         }   
89.         if (!"".equals(s.destroy()))   
90.         {   
91.             definition.setDestroyMethodName(s.destroy().trim());   
92.         }   
93.   
94.         if (LOG.isDebugEnabled())   
95.         {   
96.             LOG.debug("Reader Bean Definition[" + definition + "] with name[" + name + "]");   
97.         }   
98.         SpringAnnotationUtils.readProperties(target, definition);   
99.         return definition;   
100.     }   
101.   
102.     private String getBeanName(String name)   
103.     {   
104.         name = name.substring(0, name.length() - "Impl".length());   
105.         name = name.substring(0, 1).toLowerCase() + name.substring(1, name.length());   
106.         return name;   
107.     }   
108.   
109. }  

package com.konceptusa.infinet.annotation.handler;
import java.util.ArrayList;
import java.util.List;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.aop.framework.ProxyFactoryBean;
import org.springframework.beans.MutablePropertyValues;
import org.springframework.beans.factory.config.RuntimeBeanReference;
import org.springframework.beans.factory.support.RootBeanDefinition;
import com.konceptusa.framework.annotation.IllegalConfigException;
import com.konceptusa.framework.annotation.spring.support.AbstractSpringListAnnotationHandler;
import com.konceptusa.framework.annotation.spring.support.SpringAnnotationUtils;
import com.konceptusa.infinet.annotation.DetachDbService;
/**
* 向spring中注冊簡單服務(wù)代理實例，引用動態(tài)數(shù)據(jù)庫連結(jié)的簡單服務(wù)實例，引用hibernate shards的簡單服務(wù)實例
* @author Jwin
*
*/
public class DetachDbServiceAnnotationHandler extends AbstractSpringListAnnotationHandler<DetachDbService>
{
private final static String SESSIONFACTORYNAME = "sessionFactory";
public final static String DYNAMIC_POSTFIX = "Dynamic";
public final static String SHARDS_POSTFIX = "Shards";
private final static String DETACHDBINTERCEPTOR = "detachDBInterceptor";
private final static Log LOG = LogFactory.getLog(DetachDbServiceAnnotationHandler.class);
public Class annotation()
{
return DetachDbService.class;
}
@Override
protected void handle(DetachDbService s, Class target)
{
String name = target.getSimpleName();
if (!name.endsWith("ServiceImpl"))
{
throw new IllegalConfigException(target.getName()
+ " is not a service bean.service bean 's class name must be end with 'ServiceImpl'");
}
name = getBeanName(name);
String dynamicName = name + DYNAMIC_POSTFIX;
String dynamicSessionFactory = SESSIONFACTORYNAME + DYNAMIC_POSTFIX;
//生成動態(tài)獲取數(shù)據(jù)庫連接的簡單服務(wù)實例
createBean(s, target, dynamicName, dynamicSessionFactory);
String shardsName = name + SHARDS_POSTFIX;
String shardsFactory = SESSIONFACTORYNAME + SHARDS_POSTFIX;
//生成查詢所有數(shù)據(jù)庫的簡單服務(wù)實例
createBean(s, target, shardsName, shardsFactory);
//生成簡單服務(wù)代理類
RootBeanDefinition definition = createBeanDefinition(s, ProxyFactoryBean.class, name);
MutablePropertyValues mpv = new MutablePropertyValues();
mpv.addPropertyValue("target", new RuntimeBeanReference(shardsName));
List<String> interceptorNamesList = new ArrayList<String>();
interceptorNamesList.add(DETACHDBINTERCEPTOR);
mpv.addPropertyValue("interceptorNames", interceptorNamesList);
definition.setPropertyValues(mpv);
registerBeanDefinition(name, definition);
}
private void createBean(DetachDbService s, Class target, String name, String sessionFactory)
{
RootBeanDefinition beanDefinition = createBeanDefinition(s, target, name);
MutablePropertyValues mpv = new MutablePropertyValues();
mpv.addPropertyValue(SESSIONFACTORYNAME, new RuntimeBeanReference(sessionFactory));
beanDefinition.setPropertyValues(mpv);
registerBeanDefinition(name, beanDefinition);
}
private RootBeanDefinition createBeanDefinition(DetachDbService s, Class target, String name)
{
RootBeanDefinition definition = new RootBeanDefinition();
definition.setAbstract(false);
definition.setBeanClass(target);
definition.setSingleton(true);
definition.setLazyInit(s.lazy());
definition.setAutowireCandidate(true);
definition.setAutowireMode(s.autoWire().value());
if (!"".equals(s.init()))
{
definition.setInitMethodName(s.init().trim());
}
if (!"".equals(s.destroy()))
{
definition.setDestroyMethodName(s.destroy().trim());
}
if (LOG.isDebugEnabled())
{
LOG.debug("Reader Bean Definition[" + definition + "] with name[" + name + "]");
}
SpringAnnotationUtils.readProperties(target, definition);
return definition;
}
private String getBeanName(String name)
{
name = name.substring(0, name.length() - "Impl".length());
name = name.substring(0, 1).toLowerCase() + name.substring(1, name.length());
return name;
}
}

Java代碼

1. package com.konceptusa.infinet.detach.aop;   
2.   
3. import org.aopalliance.intercept.MethodInterceptor;   
4. import org.aopalliance.intercept.MethodInvocation;   
5. import org.apache.commons.logging.Log;   
6. import org.apache.commons.logging.LogFactory;   
7. import org.springframework.util.MethodInvoker;   
8.   
9. import com.konceptusa.framework.annotation.IllegalConfigException;   
10. import com.konceptusa.framework.core.support.ObjectFactory;   
11. import com.konceptusa.infinet.annotation.handler.DetachDbServiceAnnotationHandler;   
12. import com.konceptusa.infinet.detach.UseridAble;   
13. import com.konceptusa.infinet.detach.datasource.DataSourceIdContextHolder;   
14. import com.konceptusa.infinet.detach.datasource.UseridContextHolder;   
15.   
16. /**  
17.  * 分庫簡單服務(wù)代理  
18.  * @author Jwin  
19.  *  
20.  */  
21. public class DetachDBInterceptor implements MethodInterceptor   
22. {   
23.     private final static Log LOG = LogFactory.getLog(DetachDBInterceptor.class);   
24.     public Object invoke(MethodInvocation invoke) throws Throwable   
25.     {   
26.         int len = invoke.getArguments().length;   
27.         Long id = null;   
28.         if(len >= 1)   
29.         {              
30.             Object arg = invoke.getArguments()[0];   
31.             if(arg instanceof UseridAble)   
32.             {   
33.                 UseridAble useridAble = (UseridAble) arg;   
34.                 id = useridAble.getUserid();   
35.             }   
36.             else if(arg instanceof Long)   
37.             {   
38.                 id = (Long) arg;   
39.             }   
40.         }   
41.         if(id != null)   
42.         {   
43.             UseridContextHolder.setUserid(id);   
44.             try  
45.             {              
46.                 return invoke(invoke, id);   
47.             }finally  
48.             {   
49.                 UseridContextHolder.removeUserid();   
50.             }              
51.         }   
52.         else  
53.         {   
54.             return invoke(invoke, id);             
55.         }   
56.     }   
57.     private Object invoke(MethodInvocation invoke, Long id) throws Throwable   
58.     {   
59.         String str = invoke.getThis().toString();   
60.         int start = str.lastIndexOf(".");   
61.         int end = str.lastIndexOf("@");   
62.         String className = str.substring(start + 1, end);   
63.         String postFix = DetachDbServiceAnnotationHandler.DYNAMIC_POSTFIX;   
64.         if(id == null && DataSourceIdContextHolder.getDataSourceId() == null)   
65.         {   
66.             postFix = DetachDbServiceAnnotationHandler.SHARDS_POSTFIX;   
67.         }   
68.         String serviceName = className.substring(0,1).toLowerCase() + className.substring(1,className.length() - "Impl".length()) + postFix;   
69.         if(LOG.isDebugEnabled())   
70.             LOG.debug("select service " + serviceName + " for userid = " + id);   
71.         Object service = ObjectFactory.getManagedObject(serviceName);   
72.         if(service == null)   
73.         {   
74.             throw new IllegalConfigException("service name " + serviceName + " is not defined in spring context");   
75.         }   
76.         MethodInvoker invoker = new MethodInvoker();   
77.         invoker.setArguments(invoke.getArguments());   
78.         invoker.setTargetObject(service);   
79.         invoker.setTargetMethod(invoke.getMethod().getName());   
80.         invoker.prepare();   
81.         return invoker.invoke();   
82.     }   
83.   
84. }  

package com.konceptusa.infinet.detach.aop;
import org.aopalliance.intercept.MethodInterceptor;
import org.aopalliance.intercept.MethodInvocation;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.util.MethodInvoker;
import com.konceptusa.framework.annotation.IllegalConfigException;
import com.konceptusa.framework.core.support.ObjectFactory;
import com.konceptusa.infinet.annotation.handler.DetachDbServiceAnnotationHandler;
import com.konceptusa.infinet.detach.UseridAble;
import com.konceptusa.infinet.detach.datasource.DataSourceIdContextHolder;
import com.konceptusa.infinet.detach.datasource.UseridContextHolder;
/**
* 分庫簡單服務(wù)代理
* @author Jwin
*
*/
public class DetachDBInterceptor implements MethodInterceptor
{
private final static Log LOG = LogFactory.getLog(DetachDBInterceptor.class);
public Object invoke(MethodInvocation invoke) throws Throwable
{
int len = invoke.getArguments().length;
Long id = null;
if(len >= 1)
{
Object arg = invoke.getArguments()[0];
if(arg instanceof UseridAble)
{
UseridAble useridAble = (UseridAble) arg;
id = useridAble.getUserid();
}
else if(arg instanceof Long)
{
id = (Long) arg;
}
}
if(id != null)
{
UseridContextHolder.setUserid(id);
try
{
return invoke(invoke, id);
}finally
{
UseridContextHolder.removeUserid();
}
}
else
{
return invoke(invoke, id);
}
}
private Object invoke(MethodInvocation invoke, Long id) throws Throwable
{
String str = invoke.getThis().toString();
int start = str.lastIndexOf(".");
int end = str.lastIndexOf("@");
String className = str.substring(start + 1, end);
String postFix = DetachDbServiceAnnotationHandler.DYNAMIC_POSTFIX;
if(id == null && DataSourceIdContextHolder.getDataSourceId() == null)
{
postFix = DetachDbServiceAnnotationHandler.SHARDS_POSTFIX;
}
String serviceName = className.substring(0,1).toLowerCase() + className.substring(1,className.length() - "Impl".length()) + postFix;
if(LOG.isDebugEnabled())
LOG.debug("select service " + serviceName + " for userid = " + id);
Object service = ObjectFactory.getManagedObject(serviceName);
if(service == null)
{
throw new IllegalConfigException("service name " + serviceName + " is not defined in spring context");
}
MethodInvoker invoker = new MethodInvoker();
invoker.setArguments(invoke.getArguments());
invoker.setTargetObject(service);
invoker.setTargetMethod(invoke.getMethod().getName());
invoker.prepare();
return invoker.invoke();
}
}

Java代碼

1. package com.konceptusa.infinet.detach.datasource;   
2.   
3. import java.util.HashMap;   
4. import java.util.List;   
5. import java.util.Map;   
6. import java.util.Properties;   
7.   
8. import javax.sql.DataSource;   
9.   
10. import org.apache.commons.lang.StringUtils;   
11. import org.apache.commons.logging.Log;   
12. import org.apache.commons.logging.LogFactory;   
13. import org.springframework.jdbc.datasource.lookup.AbstractRoutingDataSource;   
14. import org.springframework.util.Assert;   
15.   
16. import com.konceptusa.framework.annotation.IllegalConfigException;   
17. import com.konceptusa.infinet.detach.config.MultiHibernateProperties;   
18. import com.konceptusa.infinet.detach.service.ISelectDBService;   
19.   
20. /**  
21.  * 動態(tài)獲取數(shù)據(jù)庫連接基類  
22.  * @author Jwin  
23.  *   
24.  */  
25. public abstract class AbstractDynamicDataSource extends AbstractRoutingDataSource   
26. {   
27.     private final static Log LOG = LogFactory.getLog(AbstractDynamicDataSource.class);   
28.     public final static int defaultDataSourceId = -1;   
29.     protected MultiHibernateProperties multiHibernateProperties;   
30.     protected ISelectDBService selectDBService;   
31.     private String newWeights;   
32.     private String oldWeights;   
33.     private Map<Integer, DataSource> dataSourceMap = new HashMap<Integer, DataSource>();   
34.     public void setSelectDBService(ISelectDBService selectDBService)   
35.     {   
36.         this.selectDBService = selectDBService;   
37.     }   
38.     public void setMultiHibernateProperties(MultiHibernateProperties multiHibernateProperties)   
39.     {   
40.         this.multiHibernateProperties = multiHibernateProperties;   
41.     }   
42.     @Override  
43.     protected Object determineCurrentLookupKey()   
44.     {   
45.         Long id = UseridContextHolder.getUserid();   
46.         return selectDBService.selectDb(id);   
47.     }   
48.        
49.     @Override  
50.     public void afterPropertiesSet()   
51.     {   
52.         LOG.info("init dynamic datasource start");   
53.         Assert.notNull(multiHibernateProperties);   
54.         Assert.notNull(selectDBService);   
55.         List<Properties> properties = multiHibernateProperties.getShardProperties();   
56.         Assert.notEmpty(properties);   
57.         int dataSourceCount = 0;   
58.         for(Properties p : properties)   
59.         {   
60.             dataSourceCount++;   
61.             createDataSource(dataSourceMap, p);   
62.         }   
63.         createDefaultDataSource(dataSourceMap);   
64.         selectDBService.setDefaultDataSourceId(defaultDataSourceId);   
65.         selectDBService.setDataSourceCount(dataSourceCount);   
66.         setTargetDataSources(dataSourceMap);   
67.         setDefaultTargetDataSource(dataSourceMap.get(defaultDataSourceId));   
68.         initWeight(dataSourceCount);   
69.         super.afterPropertiesSet();   
70.         LOG.info("init dynamic datasource success");   
71.     }   
72.     public void initWeight(int dataSourceCount)   
73.     {   
74.         Map<Integer, Integer> oldWeightMap = new HashMap<Integer, Integer>();   
75.         Map<Integer, Integer> newWeightMap = new HashMap<Integer, Integer>();   
76.         int totalOldWeight = 0;   
77.         int totalNewWeight = 0;   
78.         if(newWeights != null)   
79.         {   
80.             if(LOG.isInfoEnabled())   
81.                 LOG.info("newWeights " + newWeights);   
82.             String[] weights = StringUtils.split(newWeights,";");   
83.             if(weights.length > dataSourceCount)   
84.             {   
85.                 throw new IllegalConfigException("newWeights's length ["+weights.length+"] can't be more than dataSourceCount["+dataSourceCount+"]");   
86.             }   
87.             for(int i=0;i<weights.length;i++)   
88.             {   
89.                 int w = Integer.parseInt(weights[i]);   
90.                 for(int j=0;j<w;j++)   
91.                 {   
92.                     newWeightMap.put(totalNewWeight + j, i);   
93.                 }   
94.                 totalNewWeight += w;   
95.             }   
96.         }   
97.         else  
98.         {   
99.             totalNewWeight = dataSourceCount;   
100.             for(int i=0;i<dataSourceCount;i++)   
101.             {   
102.                 newWeightMap.put(i, i);   
103.             }   
104.         }   
105.         if(oldWeights != null)   
106.         {   
107.             if(LOG.isInfoEnabled())   
108.                 LOG.info("oldWeights " + oldWeights);   
109.             String[] weights = StringUtils.split(oldWeights,";");   
110.             if(weights.length > dataSourceCount)   
111.             {   
112.                 throw new IllegalConfigException("oldWeights's length ["+weights.length+"] can't be more than dataSourceCount["+dataSourceCount+"]");   
113.             }   
114.             for(int i=0;i<weights.length;i++)   
115.             {   
116.                 int w = Integer.parseInt(weights[i]);   
117.                 for(int j=0;j<w;j++)   
118.                 {   
119.                     oldWeightMap.put(totalOldWeight + j, i);   
120.                 }   
121.                 totalOldWeight += w;   
122.             }   
123.         }   
124.         else  
125.         {   
126.             totalOldWeight = dataSourceCount;   
127.             for(int i=0;i<dataSourceCount;i++)   
128.             {   
129.                 oldWeightMap.put(i, i);   
130.             }   
131.         }   
132.         if(LOG.isInfoEnabled())   
133.             LOG.info("totalNewWeight " + totalNewWeight + " totalOldWeight " + totalOldWeight);   
134.         selectDBService.setTotalNewWeight(totalNewWeight);   
135.         selectDBService.setNewWeightIdMap(newWeightMap);   
136.         selectDBService.setTotalOldWeight(totalOldWeight);   
137.         selectDBService.setOldWeightIdMap(oldWeightMap);   
138.     }   
139.     protected abstract void createDataSource(Map<Integer, DataSource> dataSourceMap, Properties p);   
140.     protected abstract void createDefaultDataSource(Map<Integer, DataSource> dataSourceMap);   
141.     public void setNewWeights(String newWeights)   
142.     {   
143.         this.newWeights = newWeights;   
144.     }   
145.     public void setOldWeights(String oldWeights)   
146.     {   
147.         this.oldWeights = oldWeights;   
148.     }   
149.     public Map<Integer, DataSource> getDataSourceMap()   
150.     {   
151.         return dataSourceMap;   
152.     }   
153.   
154. }  

package com.konceptusa.infinet.detach.datasource;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Properties;
import javax.sql.DataSource;
import org.apache.commons.lang.StringUtils;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.jdbc.datasource.lookup.AbstractRoutingDataSource;
import org.springframework.util.Assert;
import com.konceptusa.framework.annotation.IllegalConfigException;
import com.konceptusa.infinet.detach.config.MultiHibernateProperties;
import com.konceptusa.infinet.detach.service.ISelectDBService;
/**
* 動態(tài)獲取數(shù)據(jù)庫連接基類
* @author Jwin
*
*/
public abstract class AbstractDynamicDataSource extends AbstractRoutingDataSource
{
private final static Log LOG = LogFactory.getLog(AbstractDynamicDataSource.class);
public final static int defaultDataSourceId = -1;
protected MultiHibernateProperties multiHibernateProperties;
protected ISelectDBService selectDBService;
private String newWeights;
private String oldWeights;
private Map<Integer, DataSource> dataSourceMap = new HashMap<Integer, DataSource>();
public void setSelectDBService(ISelectDBService selectDBService)
{
this.selectDBService = selectDBService;
}
public void setMultiHibernateProperties(MultiHibernateProperties multiHibernateProperties)
{
this.multiHibernateProperties = multiHibernateProperties;
}
@Override
protected Object determineCurrentLookupKey()
{
Long id = UseridContextHolder.getUserid();
return selectDBService.selectDb(id);
}
@Override
public void afterPropertiesSet()
{
LOG.info("init dynamic datasource start");
Assert.notNull(multiHibernateProperties);
Assert.notNull(selectDBService);
List<Properties> properties = multiHibernateProperties.getShardProperties();
Assert.notEmpty(properties);
int dataSourceCount = 0;
for(Properties p : properties)
{
dataSourceCount++;
createDataSource(dataSourceMap, p);
}
createDefaultDataSource(dataSourceMap);
selectDBService.setDefaultDataSourceId(defaultDataSourceId);
selectDBService.setDataSourceCount(dataSourceCount);
setTargetDataSources(dataSourceMap);
setDefaultTargetDataSource(dataSourceMap.get(defaultDataSourceId));
initWeight(dataSourceCount);
super.afterPropertiesSet();
LOG.info("init dynamic datasource success");
}
public void initWeight(int dataSourceCount)
{
Map<Integer, Integer> oldWeightMap = new HashMap<Integer, Integer>();
Map<Integer, Integer> newWeightMap = new HashMap<Integer, Integer>();
int totalOldWeight = 0;
int totalNewWeight = 0;
if(newWeights != null)
{
if(LOG.isInfoEnabled())
LOG.info("newWeights " + newWeights);
String[] weights = StringUtils.split(newWeights,";");
if(weights.length > dataSourceCount)
{
throw new IllegalConfigException("newWeights's length ["+weights.length+"] can't be more than dataSourceCount["+dataSourceCount+"]");
}
for(int i=0;i<weights.length;i++)
{
int w = Integer.parseInt(weights[i]);
for(int j=0;j<w;j++)
{
newWeightMap.put(totalNewWeight + j, i);
}
totalNewWeight += w;
}
}
else
{
totalNewWeight = dataSourceCount;
for(int i=0;i<dataSourceCount;i++)
{
newWeightMap.put(i, i);
}
}
if(oldWeights != null)
{
if(LOG.isInfoEnabled())
LOG.info("oldWeights " + oldWeights);
String[] weights = StringUtils.split(oldWeights,";");
if(weights.length > dataSourceCount)
{
throw new IllegalConfigException("oldWeights's length ["+weights.length+"] can't be more than dataSourceCount["+dataSourceCount+"]");
}
for(int i=0;i<weights.length;i++)
{
int w = Integer.parseInt(weights[i]);
for(int j=0;j<w;j++)
{
oldWeightMap.put(totalOldWeight + j, i);
}
totalOldWeight += w;
}
}
else
{
totalOldWeight = dataSourceCount;
for(int i=0;i<dataSourceCount;i++)
{
oldWeightMap.put(i, i);
}
}
if(LOG.isInfoEnabled())
LOG.info("totalNewWeight " + totalNewWeight + " totalOldWeight " + totalOldWeight);
selectDBService.setTotalNewWeight(totalNewWeight);
selectDBService.setNewWeightIdMap(newWeightMap);
selectDBService.setTotalOldWeight(totalOldWeight);
selectDBService.setOldWeightIdMap(oldWeightMap);
}
protected abstract void createDataSource(Map<Integer, DataSource> dataSourceMap, Properties p);
protected abstract void createDefaultDataSource(Map<Integer, DataSource> dataSourceMap);
public void setNewWeights(String newWeights)
{
this.newWeights = newWeights;
}
public void setOldWeights(String oldWeights)
{
this.oldWeights = oldWeights;
}
public Map<Integer, DataSource> getDataSourceMap()
{
return dataSourceMap;
}
}

Java代碼

1. package com.konceptusa.infinet.detach.datasource;   
2.   
3. import java.beans.PropertyVetoException;   
4. import java.util.Map;   
5. import java.util.Properties;   
6.   
7. import javax.sql.DataSource;   
8.   
9. import org.apache.commons.logging.Log;   
10. import org.apache.commons.logging.LogFactory;   
11.   
12. import com.konceptusa.framework.annotation.IllegalConfigException;   
13. import com.konceptusa.infinet.detach.config.MultiHibernateProperties;   
14. import com.mchange.v2.c3p0.ComboPooledDataSource;   
15.   
16. /**  
17.  * 基于c3p0連接池的動態(tài)獲取連接類  
18.  * @author Jwin  
19.  *   
20.  */  
21. public class DynamicC3p0DataSource extends AbstractDynamicDataSource   
22. {   
23.     private final static Log LOG = LogFactory.getLog(DynamicC3p0DataSource.class);   
24.     private int initialSize = 1;   
25.     private int maxActive = 1;   
26.     private int minActive = 1;   
27.     private int maxIdleTime = 30;   
28.     private String automaticTestTable = "Test";   
29.     private int acquireIncrement = 3;   
30.     private int maxStatements = 100;   
31.     private int maxStatementsPerConnection = 3;   
32.     private int numHelperThreads = 3;   
33.     private int idleConnectionTestPeriod = 30;   
34.     protected void createDefaultDataSource(Map<Integer, DataSource> dataSourceMap)   
35.     {   
36.         ComboPooledDataSource dataSource = new ComboPooledDataSource();   
37.         dataSource.setUser("sa");   
38.         dataSource.setPassword("");   
39.         dataSource.setJdbcUrl("jdbc:hsqldb:mem:" + getClass().getSimpleName().toLowerCase());   
40.         try  
41.         {   
42.             dataSource.setDriverClass("org.hsqldb.jdbcDriver");   
43.         } catch (PropertyVetoException e)   
44.         {   
45.             throw new IllegalConfigException(e);   
46.         }   
47.         dataSource.setInitialPoolSize(initialSize);   
48.         dataSource.setMaxPoolSize(maxActive);   
49.         dataSource.setMinPoolSize(minActive);   
50.         dataSource.setMaxIdleTime(maxIdleTime);   
51.         dataSource.setAcquireIncrement(acquireIncrement);   
52.         dataSource.setNumHelperThreads(numHelperThreads);   
53.         dataSource.setAutomaticTestTable(automaticTestTable);   
54.         dataSource.setMaxStatements(maxStatements);   
55.         dataSource.setMaxStatementsPerConnection(maxStatementsPerConnection);   
56.         dataSource.setIdleConnectionTestPeriod(idleConnectionTestPeriod);   
57.         dataSourceMap.put(defaultDataSourceId, dataSource);   
58.     }   
59.     @Override  
60.     protected void createDataSource(Map<Integer, DataSource> dataSourceMap, Properties p)   
61.     {   
62.         ComboPooledDataSource dataSource = new ComboPooledDataSource();   
63.         dataSource.setJdbcUrl(p.getProperty(MultiHibernateProperties.connectionUrlKey));   
64.         LOG.info("init datasource url " + dataSource.getJdbcUrl());   
65.         dataSource.setUser(p.getProperty(MultiHibernateProperties.connectionUsernameKey));   
66.         dataSource.setPassword(p.getProperty(MultiHibernateProperties.connectionPasswordKey));   
67.         try  
68.         {   
69.             dataSource.setDriverClass(p.getProperty(MultiHibernateProperties.connectionDriverClassKey));   
70.         } catch (PropertyVetoException e)   
71.         {   
72.             throw new IllegalConfigException(e);   
73.         }   
74.         dataSource.setInitialPoolSize(initialSize);   
75.         dataSource.setMaxPoolSize(maxActive);   
76.         dataSource.setMinPoolSize(minActive);   
77.         dataSource.setMaxIdleTime(maxIdleTime);   
78.         dataSource.setAcquireIncrement(acquireIncrement);   
79.         dataSource.setNumHelperThreads(numHelperThreads);   
80.         dataSource.setAutomaticTestTable(automaticTestTable);   
81.         dataSource.setMaxStatements(maxStatements);   
82.         dataSource.setMaxStatementsPerConnection(maxStatementsPerConnection);   
83.         dataSource.setIdleConnectionTestPeriod(idleConnectionTestPeriod);   
84.         String id = p.getProperty(MultiHibernateProperties.shardIdKey);   
85.         dataSourceMap.put(Integer.parseInt(id), dataSource);   
86.     }   
87.     public void setInitialSize(int initialSize)   
88.     {   
89.         this.initialSize = initialSize;   
90.     }   
91.     public void setMaxActive(int maxActive)   
92.     {   
93.         this.maxActive = maxActive;   
94.     }   
95.     public void setMaxIdleTime(int maxIdle)   
96.     {   
97.         this.maxIdleTime = maxIdle;   
98.     }      
99.     public void setAcquireIncrement(int acquireIncrement)   
100.     {   
101.         this.acquireIncrement = acquireIncrement;   
102.     }   
103.     public void setMaxStatements(int maxStatements)   
104.     {   
105.         this.maxStatements = maxStatements;   
106.     }   
107.     public void setMaxStatementsPerConnection(int maxStatementsPerConnection)   
108.     {   
109.         this.maxStatementsPerConnection = maxStatementsPerConnection;   
110.     }   
111.     public void setNumHelperThreads(int numHelperThreads)   
112.     {   
113.         this.numHelperThreads = numHelperThreads;   
114.     }   
115.     public void setAutomaticTestTable(String automaticTestTable)   
116.     {   
117.         this.automaticTestTable = automaticTestTable;   
118.     }   
119.     public void setMinActive(int minActive)   
120.     {   
121.         this.minActive = minActive;   
122.     }   
123.     public void setIdleConnectionTestPeriod(int idleConnectionTestPeriod)   
124.     {   
125.         this.idleConnectionTestPeriod = idleConnectionTestPeriod;   
126.     }   
127.        
128.   
129. }  

package com.konceptusa.infinet.detach.datasource;
import java.beans.PropertyVetoException;
import java.util.Map;
import java.util.Properties;
import javax.sql.DataSource;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import com.konceptusa.framework.annotation.IllegalConfigException;
import com.konceptusa.infinet.detach.config.MultiHibernateProperties;
import com.mchange.v2.c3p0.ComboPooledDataSource;
/**
* 基于c3p0連接池的動態(tài)獲取連接類
* @author Jwin
*
*/
public class DynamicC3p0DataSource extends AbstractDynamicDataSource
{
private final static Log LOG = LogFactory.getLog(DynamicC3p0DataSource.class);
private int initialSize = 1;
private int maxActive = 1;
private int minActive = 1;
private int maxIdleTime = 30;
private String automaticTestTable = "Test";
private int acquireIncrement = 3;
private int maxStatements = 100;
private int maxStatementsPerConnection = 3;
private int numHelperThreads = 3;
private int idleConnectionTestPeriod = 30;
protected void createDefaultDataSource(Map<Integer, DataSource> dataSourceMap)
{
ComboPooledDataSource dataSource = new ComboPooledDataSource();
dataSource.setUser("sa");
dataSource.setPassword("");
dataSource.setJdbcUrl("jdbc:hsqldb:mem:" + getClass().getSimpleName().toLowerCase());
try
{
dataSource.setDriverClass("org.hsqldb.jdbcDriver");
} catch (PropertyVetoException e)
{
throw new IllegalConfigException(e);
}
dataSource.setInitialPoolSize(initialSize);
dataSource.setMaxPoolSize(maxActive);
dataSource.setMinPoolSize(minActive);
dataSource.setMaxIdleTime(maxIdleTime);
dataSource.setAcquireIncrement(acquireIncrement);
dataSource.setNumHelperThreads(numHelperThreads);
dataSource.setAutomaticTestTable(automaticTestTable);
dataSource.setMaxStatements(maxStatements);
dataSource.setMaxStatementsPerConnection(maxStatementsPerConnection);
dataSource.setIdleConnectionTestPeriod(idleConnectionTestPeriod);
dataSourceMap.put(defaultDataSourceId, dataSource);
}
@Override
protected void createDataSource(Map<Integer, DataSource> dataSourceMap, Properties p)
{
ComboPooledDataSource dataSource = new ComboPooledDataSource();
dataSource.setJdbcUrl(p.getProperty(MultiHibernateProperties.connectionUrlKey));
LOG.info("init datasource url " + dataSource.getJdbcUrl());
dataSource.setUser(p.getProperty(MultiHibernateProperties.connectionUsernameKey));
dataSource.setPassword(p.getProperty(MultiHibernateProperties.connectionPasswordKey));
try
{
dataSource.setDriverClass(p.getProperty(MultiHibernateProperties.connectionDriverClassKey));
} catch (PropertyVetoException e)
{
throw new IllegalConfigException(e);
}
dataSource.setInitialPoolSize(initialSize);
dataSource.setMaxPoolSize(maxActive);
dataSource.setMinPoolSize(minActive);
dataSource.setMaxIdleTime(maxIdleTime);
dataSource.setAcquireIncrement(acquireIncrement);
dataSource.setNumHelperThreads(numHelperThreads);
dataSource.setAutomaticTestTable(automaticTestTable);
dataSource.setMaxStatements(maxStatements);
dataSource.setMaxStatementsPerConnection(maxStatementsPerConnection);
dataSource.setIdleConnectionTestPeriod(idleConnectionTestPeriod);
String id = p.getProperty(MultiHibernateProperties.shardIdKey);
dataSourceMap.put(Integer.parseInt(id), dataSource);
}
public void setInitialSize(int initialSize)
{
this.initialSize = initialSize;
}
public void setMaxActive(int maxActive)
{
this.maxActive = maxActive;
}
public void setMaxIdleTime(int maxIdle)
{
this.maxIdleTime = maxIdle;
}
public void setAcquireIncrement(int acquireIncrement)
{
this.acquireIncrement = acquireIncrement;
}
public void setMaxStatements(int maxStatements)
{
this.maxStatements = maxStatements;
}
public void setMaxStatementsPerConnection(int maxStatementsPerConnection)
{
this.maxStatementsPerConnection = maxStatementsPerConnection;
}
public void setNumHelperThreads(int numHelperThreads)
{
this.numHelperThreads = numHelperThreads;
}
public void setAutomaticTestTable(String automaticTestTable)
{
this.automaticTestTable = automaticTestTable;
}
public void setMinActive(int minActive)
{
this.minActive = minActive;
}
public void setIdleConnectionTestPeriod(int idleConnectionTestPeriod)
{
this.idleConnectionTestPeriod = idleConnectionTestPeriod;
}
}

Java代碼

1. package com.konceptusa.infinet.imsupport.detach;   
2.   
3. import java.util.ArrayList;   
4. import java.util.Collection;   
5. import java.util.Collections;   
6. import java.util.List;   
7.   
8. import org.apache.commons.logging.Log;   
9. import org.apache.commons.logging.LogFactory;   
10. import org.springframework.transaction.annotation.Propagation;   
11. import org.springframework.transaction.annotation.Transactional;   
12.   
13. import com.konceptusa.framework.annotation.IllegalConfigException;   
14. import com.konceptusa.framework.core.dao.HibernateQueryListCallback;   
15. import com.konceptusa.framework.core.dao.hql.Hql;   
16. import com.konceptusa.framework.core.service.BaseServiceSupport;   
17. import com.konceptusa.framework.core.service.Page;   
18. import com.konceptusa.framework.core.support.ObjectFactory;   
19. import com.konceptusa.infinet.annotation.handler.DetachDbServiceAnnotationHandler;   
20. import com.konceptusa.infinet.detach.CountId;   
21. import com.konceptusa.infinet.detach.CountIdComparetor;   
22. import com.konceptusa.infinet.detach.MagrateAble;   
23. import com.konceptusa.infinet.detach.QueryListAble;   
24. import com.konceptusa.infinet.detach.datasource.UseridContextHolder;   
25.   
26. /**  
27.  * 多個數(shù)據(jù)庫綜合查詢，簡單服務(wù)類父類  
28.  * @author Jwin  
29.  *  
30.  * @param <T>  
31.  */  
32. @Transactional(readOnly=true, rollbackFor = Exception.class)   
33. public abstract class BaseServiceSupportForMulti<T> extends BaseServiceSupport<T> implements QueryListAble<T>,MagrateAble<T>   
34. {   
35.     private final static Log LOG = LogFactory.getLog(BaseServiceSupportForMulti.class);   
36.     @Override  
37.     protected int findCountByHql(Hql hql)   
38.     {   
39.         List<Long> countList = (List<Long>) getHibernateTemplate().execute(   
40.                 new HibernateQueryListCallback(new Hql("select count(*) "  
41.                         + hql.getHql(), hql.getCache(), hql.getParameters())));   
42.         Long counts = 0L;   
43.         for(Long count : countList)   
44.         {   
45.             counts += count;   
46.         }   
47.         return counts.intValue();   
48.     }   
49.     @Transactional(readOnly=true, rollbackFor = Exception.class,propagation=Propagation.NOT_SUPPORTED)   
50.     public List<T> queryList(Hql hql, int from, int offset)   
51.     {   
52.         return queryListByHql(hql, from, offset);   
53.     }   
54.   
55.     public List<CountId> queryCount(Hql hql)   
56.     {   
57.         List<Object[]> list = queryListByHql(hql);   
58.         List<CountId> countList = new ArrayList<CountId>(list.size());    
59.         for(Object[] l : list)   
60.         {   
61.             if(l[1] != null)   
62.             {                  
63.                 CountId count = new CountId((Long) l[1],(Long)l[0]);   
64.                 countList.add(count);   
65.             }   
66.         }   
67.         Collections.sort(countList, new CountIdComparetor());   
68.         return countList;   
69.     }   
70.     protected String getBeanName(String name)   
71.     {   
72.         name = name.substring(0, name.length() - "Impl".length());   
73.         name = name.substring(0, 1).toLowerCase() + name.substring(1, name.length());   
74.         return name;   
75.     }   
76.     protected Page queryPageByHql(Hql hql,String useridName, int start, int offset)   
77.     {   
78.         Hql countHql = new Hql("select count(*),min(" + useridName + ") "  
79.                 + hql.getHql(), hql.getCache(), hql.getParameters());   
80.         return queryPageByHql(countHql, hql, start, offset);   
81.     }   
82.     //先查出各個數(shù)據(jù)庫的總數(shù)及標識，然后對標識進行排序，最后根據(jù)這個結(jié)果遍歷數(shù)據(jù)庫進行分頁查找，找滿結(jié)果則返回。   
83.     private Page queryPageByHql(Hql countHql,Hql listHql,int start, int offset)   
84.     {   
85.         QueryListAble<T> serviceShards = getShardsService();   
86.         QueryListAble<T> serviceDynamic = getDynamicService();   
87.         List<CountId> countList = serviceShards.queryCount(countHql);   
88.         //相對于當前之前所有數(shù)據(jù)庫的總數(shù)偏移   
89.         int totalCount = 0;   
90.         //相對于所有數(shù)據(jù)庫的結(jié)束偏移   
91.         int end = start + offset;   
92.         //相對于當前數(shù)據(jù)庫的開始偏移量   
93.         int startRelative = -1;   
94.         List<T> queryList = new ArrayList<T>(offset);   
95.         for(CountId count : countList)   
96.         {   
97.             totalCount += count.getCount();   
98.             //之前所有庫總數(shù)小于開始偏移量，繼續(xù)下一個數(shù)據(jù)庫   
99.             if(totalCount < start)   
100.             {   
101.                 continue;   
102.             }   
103.             //之前所有庫總數(shù)第一次大于開始偏移量   
104.             if(startRelative == -1)   
105.             {                  
106.                 startRelative = count.getCount().intValue() - (totalCount - start);   
107.             }   
108.             else  
109.             {   
110.                 startRelative = 0;   
111.             }   
112.             int relativeCount = totalCount - end;   
113.             if(relativeCount >= 0)   
114.             {   
115.                 UseridContextHolder.setUserid(count.getId());   
116.                 try  
117.                 {   
118.                     //計算相對于當前庫的偏移   
119.                     int offsetRelative = count.getCount().intValue() - relativeCount - startRelative;   
120.                     LOG.debug("query from " + startRelative + " offset " + offsetRelative + " for min(userid)=" + count.getId());   
121.                     queryList.addAll(serviceDynamic.queryList(listHql, startRelative, offsetRelative));                    
122.                 }finally  
123.                 {   
124.                     UseridContextHolder.removeUserid();   
125.                 }   
126.                 break;   
127.             }   
128.             UseridContextHolder.setUserid(count.getId());   
129.             try  
130.             {                  
131.                 //計算相對于當前庫的偏移   
132.                 int offsetRelative = totalCount - startRelative;   
133.                 LOG.debug("query from " + startRelative + " offset " + offsetRelative + " for min(userid)=" + count.getId());   
134.                 queryList.addAll(serviceDynamic.queryList(listHql, startRelative, offsetRelative));                    
135.             } finally  
136.             {   
137.                 UseridContextHolder.removeUserid();   
138.             }   
139.         }   
140.         totalCount = 0;   
141.         for(CountId count : countList)   
142.         {   
143.             totalCount += count.getCount();   
144.         }   
145.         return new Page<T>(totalCount, queryList);                   
146.     }   
147.     protected Page queryPageByHql(String hqlstr,String useridName, int start, int offset,Object ... values)   
148.     {   
149.         Hql listHql = Hql.createIndexHql(