package net.qysoft;
import java.io.File;
import java.io.FileOutputStream;
import java.sql.Blob;
import java.sql.Connection;
import java.sql.SQLException;
/**
* java 中对Blob数据的操作数据库的创建代码:
* (1)db2 => create table blobTest ( id int not null generated always as identity, image blob )
*添加用户java,密码java
* (2) db2=>! net
* user java java /add java分配权限
*(3)db2 => grant select,insert,update,delete on
* table weihuachao.blobTest to user java
*
*
* @author weihuachao
* 以下代码在microsoft 2003 系统,DB2 9.0中测试成功.
*
*/
//类的定义开始------------------------------------------------------------
public class Test {
public static void main(String[] args) throws Exception {
Test test = new Test();
Connection conn = test.createConnection();
// Blob对象的插入的方法:
try {
// 创建插入语句.
java.sql.PreparedStatement preparedStatement = conn
.prepareStatement("insert into weihuachao.blobTest(image)values(?)");
//创建文件对象:
File file=new File("c:/a.jpg");
// 创建流对象:
java.io.BufferedInputStream imageInput = new java.io.BufferedInputStream(
new java.io.FileInputStream(file));
//参数赋值:
preparedStatement.setBinaryStream(1, imageInput,(int) file.length());
//执行语句
preparedStatement.executeUpdate();
//------------------------------------------------------------------
//Blob的读取工作:
java.sql.Statement st=conn.createStatement();
java.sql.ResultSet rs=st.executeQuery("select image from weihuachao.blobTest");
while(rs.next())
{
//读取Blob对象
Blob blob= (Blob) rs.getBlob(1);
//Blob对象转化为InputStream流
java.io.InputStream inputStream =blob.getBinaryStream();
//要写入的文件
File fileOutput = new File("c:/backa.jpg");
//文件的写入流的定义
FileOutputStream fo = new FileOutputStream(fileOutput);
int c;
//读取流并写入到文件中
while ((c = inputStream.read()) != -1)
fo.write(c);
//流的关闭:
fo.close();
}
} catch (SQLException e) {
// TODO 自动生成 catch 块
e.printStackTrace();
}catch(java.io.FileNotFoundException ex)
{
ex.printStackTrace();
}catch(java.io.IOException ex)
{
ex.printStackTrace();
}
finally
{
try {
conn.close();
} catch (SQLException e) {
// TODO 自动生成 catch 块
e.printStackTrace();
}
}
}
/**
* 定义数据库连接的方法
*
* @return
*/
private Connection createConnection() {
Connection conn = null;
try {
Class.forName("COM.ibm.db2.jdbc.app.DB2Driver");
conn = java.sql.DriverManager.getConnection("jdbc:db2:sample",
"java", "java");
} catch (SQLException ex1) {
ex1.printStackTrace();
} catch (ClassNotFoundException ex) {
ex.printStackTrace();
}
return conn;
}
}//结束.
总结: JAVA 对DB2中的BLOB对象的操作,主要是使用流的技术实现.对BLOB的实现主要步骤有:
(1)定义要写入的文件 File file=new File("c:/a.jpg");
(2)定义文件的写入流
java.io.BufferedInputStream imageInput = new java.io.BufferedInputStream(
new java.io.FileInputStream(file));
(3)使用函数写入:
preparedStatement.setBinaryStream(1, imageInput,(int) file.length());
(4)执行SQL语句:
对BLOB的读取采取的步骤有:
(1)读取Blob的对象: Blob blob= (Blob) rs.getBlob(1);
(2)把Blob的对象转化为流:
java.io.InputStream inputStream =blob.getBinaryStream();
(3)定义要写入的文件
File fileOutput = new File("c:/backa.jpg");
(4)文件的写入流的定义
FileOutputStream fo = new FileOutputStream(fileOutput);
(5)写入文件(流的写入技术,就不多讲了)
int c;
while ((c = inputStream.read()) != -1)
{
fo.write(c);
}
//END