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oracle blob數據存取

Oracle中的lob (Large Object)可以存儲非常大的數據（可能是4GB），這樣就可以通過將文件或其它任何對象序列化成字節輸出流(OutputStream)后寫入數據庫，之后使用字節輸入流(InputStream)將數據讀出然后反序列化為原始文件或對象。操作時需要使用oracle的JDBC包，它擴展了sun的 JDBC包中的Blob對象。
以下是一個保存圖片進數據庫的例子:
1.servlet:用于保存圖片并將圖片輸出

Java代碼

package com.logcd.servlet;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.sql.CallableStatement;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.sql.Types;
import java.util.Iterator;
import java.util.List;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import oracle.sql.BLOB;
import org.apache.commons.fileupload.FileItem;
import org.apache.commons.fileupload.FileUploadException;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;
public class ImageServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
/**
* 處理請求
* @throws FileUploadException
*/
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
Iterator<FileItem> i = getFileItem(request);
String title = "";
byte[] data = null;
while (i.hasNext()) {
FileItem fi = (FileItem) i.next();
if (fi.isFormField()) {// 取得表單域
if(fi.getFieldName().equalsIgnoreCase("title")){
title = new String(fi.getString().getBytes("iso8859-1"),"gbk");
}
} else {// 取文件域
data = fi.get();//文件二進制數據
}
}
Integer id = saveImageUseProc(data,title);//saveImage(data, title);//存入
//outputImage(response, id);//讀出
outputImageUseProc(response,id);
}
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doPost(request, response);
}
/**
* 通過SQL保存圖片
* @param data
* @param title
*/
@SuppressWarnings("deprecation")
public static Integer saveImage(byte[] data, String title) {
Connection conn = getConnection();
Integer id = (int) (Math.random() * 100000);
String sql = "insert into t_image(id,title,image) values(" + id + ",'"
+ title + "',empty_blob())";
Statement stmt;
OutputStream outStream = null;
try {
conn.setAutoCommit(false);// 如果不關閉會報-->"錯誤:讀取違反順序"
stmt = conn.createStatement();
stmt.execute(sql);
String sqll = "select image from t_image where id=" + id
+ " for update";
ResultSet rs = stmt.executeQuery(sqll);
if (rs.next()) {
BLOB blob = (BLOB) rs.getBlob("image");
outStream = blob.getBinaryOutputStream();
// data是傳入的byte數組，定義：byte[] data
outStream.write(data, 0, data.length);
outStream.flush();
outStream.close();
conn.commit();
}
} catch (Exception e) {
try {
conn.rollback();
} catch (SQLException e1) {
e1.printStackTrace();
}
e.printStackTrace();
} finally {
try {
conn.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
return id;
}
/**
* 調用存儲過程保存圖片
* @param data
* @param title
* @return
*/
@SuppressWarnings("deprecation")
public static Integer saveImageUseProc(byte[] data, String title){
Integer id = null;
BLOB blob = null;
OutputStream outStream;
Connection conn = getConnection();
try{
conn.setAutoCommit(false);
String call="{call OPERATE_BLOB.SAVE_BLOB_IMAGE(?,?,?)}";//調用語句
CallableStatement proc=conn.prepareCall(call);//調用存儲過程
proc.setString(1, title);
proc.registerOutParameter(2, Types.BLOB);
proc.registerOutParameter(3, Types.INTEGER);
proc.execute();
blob = (BLOB)proc.getBlob(2);
id = proc.getInt(3);//返回結果
outStream = blob.getBinaryOutputStream();
outStream.write(data, 0, data.length);
outStream.flush();
outStream.close();
proc.close();
conn.commit();
}catch(Exception e){
e.printStackTrace();
}finally{
try {
conn.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
return id;
}
/**
* 輸出保存的圖片
* @param response
* @param id
*/
public static void outputImage(HttpServletResponse response, Integer id) {
Connection con = getConnection();
byte[] data = null;
try{
Statement st = con.createStatement();
ResultSet rs = st.executeQuery("select image from t_image where id="
+ id);
if (rs.next()) {
BLOB blob = (BLOB)rs.getBlob("image");
InputStream inStream = blob.getBinaryStream();
int bufferSize = blob.getBufferSize();
data = new byte[bufferSize];
int count = inStream.read(data, 0, bufferSize);
while(count != -1){//讀出字節數據
response.getOutputStream().write(data,0,count);
count = inStream.read(data, 0, bufferSize);
}
inStream.close();
}
}catch(Exception e){
e.printStackTrace();
}finally{
try {
con.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
}
/**
* 調用存儲過程輸出圖片
* @param response
* @param id
*/
public static void outputImageUseProc(HttpServletResponse response, Integer id){
Connection conn = getConnection();
try{
String call = "{call OPERATE_BLOB.QUERY_BLOB_IMAGE(?,?)}";
CallableStatement proc=conn.prepareCall(call);//調用存儲過程
proc.setInt(1, id);
proc.registerOutParameter(2, Types.BLOB);
proc.execute();
BLOB blob = (BLOB)proc.getBlob(2);
InputStream inStream = blob.getBinaryStream();
int bufferSize = blob.getBufferSize();
byte[] data = new byte[bufferSize];
int count = inStream.read(data, 0, bufferSize);
while(count != -1){//讀出字節數據
response.getOutputStream().write(data,0,count);
count = inStream.read(data, 0, bufferSize);
}
inStream.close();
}catch(Exception e){
e.printStackTrace();
}finally{
try {
conn.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
}
/**
* 取得所有表單數據
* @param request
* @return
*/
@SuppressWarnings("unchecked")
public static Iterator<FileItem> getFileItem(HttpServletRequest request) {
DiskFileItemFactory factory = new DiskFileItemFactory();
factory.setSizeThreshold(4096); // 設置緩沖區大小，這里是4kb
ServletFileUpload upload = new ServletFileUpload(factory);
upload.setSizeMax(4194304); // 設置最大文件尺寸，這里是4MB
List<FileItem> items = null;
Iterator<FileItem> i = null;
try {
items = upload.parseRequest(request);
i = items.iterator();
} catch (FileUploadException e) {
e.printStackTrace();
}
return i;
}
/**
* 取得數據庫連接
*
* @return
*/
public static Connection getConnection() {
String driver = "oracle.jdbc.driver.OracleDriver";
String url = "jdbc:oracle:thin:@195.2.199.6:1521:orcl";
Connection conn = null;
try {
Class.forName(driver);
conn = DriverManager.getConnection(url, "testdb", "logcd");
} catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (SQLException ex) {
ex.printStackTrace();
}
return conn;
}
}

2.所用到的存儲過程

Sql代碼

CREATE OR REPLACE PACKAGE BODY OPERATE_BLOB AS
PROCEDURE SAVE_BLOB_IMAGE(
PC_TITLE IN VARCHAR2,
PB_IMAGE OUT BLOB,
PN_ID OUT INTEGER
)AS
v_id INTEGER;
BEGIN
SELECT nvl(MAX(id),1000) + 1 INTO v_id FROM t_image;
PN_ID := v_id;
INSERT INTO t_image(id,title,image) values(v_id,PC_TITLE,empty_blob())
RETURNING image INTO PB_IMAGE;
END;
PROCEDURE QUERY_BLOB_IMAGE(
PN_ID IN INTEGER,
PB_IMAGE OUT BLOB
)AS
BEGIN
SELECT image INTO PB_IMAGE FROM t_image WHERE id = PN_ID;
END;
END;

3.web.xml配置servlet

Xml代碼

<servlet>
<servlet-name>ImageServlet</servlet-name>
<servlet-class>com.logcd.servlet.ImageServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>ImageServlet</servlet-name>
<url-pattern>/imageServlet</url-pattern>
</servlet-mapping>

4.在image.html頁面中調用下

Html代碼

<HTML>
<HEAD>
<TITLE>Image File</TITLE>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312">
</HEAD>
<FORM method="POST" encType="multipart/form-data" action="imageServlet">
<INPUT type="text" name="title">
<BR>
<INPUT type="file" name="image">
<BR>
<INPUT type="submit" value="提交">
</FORM>
<BODY>
</BODY>
</HTML>

posted on 2012-06-19 17:42 大龍閱讀(660) 評論(0) 編輯收藏引用

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oracle blob數據存取