使用JDBC写入blob数据到数据库以及读取数据

来源：互联网发布：淘宝直通车ppc 编辑：程序博客网时间：2024/05/14 15:04

package com.yucheng.jdbc;

import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.OutputStream;
import java.sql.Blob;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.Statement;

import javax.print.attribute.standard.OutputDeviceAssigned;

import org.junit.Test;

public class JdbcTest {

   /**
   * 读取Blob数据
   */
   @Test
   public void testReadBlob(){

       Connection conn =null;
       PreparedStatement preStatement=null;
       ResultSet resultSet=null;

       try {
           conn=JDBCTools.getConnecition();
           String sql="select * from testBlob where id=1";
           preStatement=conn.prepareStatement(sql);
           resultSet=preStatement.executeQuery();
           if(resultSet.next()){
               int id=resultSet.getInt(1);
               String name=resultSet.getString(2);
               int age=resultSet.getInt(3);
               Blob pic=resultSet.getBlob(4);

               InputStream in=pic.getBinaryStream();
               OutputStream out=new FileOutputStream("out.jpg");

               byte[] buffer =new byte[1024];

               int len=0;
               while((len=in.read(buffer))!=-1){
                   out.write(buffer);
                   out.flush();
               }

               out.close();
               in.close();
           }


       } catch (Exception e) {
           e.printStackTrace();
       }finally{
           JDBCTools.release(preStatement, conn, resultSet);
       }

   }

   /**
   * 插入Blob类型的数据,使用的是PrepareStatement的setBlob(index,stream)方法
   */
   @Test
   public void testInsertBlob(){
       Connection conn =null;
       PreparedStatement preStatement=null;

       try {
           conn=JDBCTools.getConnecition();
           String sql="insert into testBlob(name,age,pic) values(?,?,?)";
           preStatement=conn.prepareStatement(sql);
           preStatement.setString(1, "魅力");
           preStatement.setInt(2, 22);
           InputStream pic=new FileInputStream("hello.jpg");
           preStatement.setBlob(3,pic);

           preStatement.executeUpdate();

       } catch (Exception e) {
           e.printStackTrace();
       }finally{
           JDBCTools.release(preStatement, conn, null);
       }
   }

   /**
   * 得到主键值
   */
   @Test
   public void testGetKeyValue() {

       Connection conn=null;
       PreparedStatement preStatement=null;
       ResultSet resultSet=null;
       try {
           conn=JDBCTools.getConnecition();
           String sql="insert into person(name) values(?)";
           preStatement=conn.prepareStatement(sql,
                   Statement.RETURN_GENERATED_KEYS);

           preStatement.setString(1, "meimei");

           preStatement.executeUpdate();

           resultSet=preStatement.getGeneratedKeys();
           if(resultSet.next()){
               System.out.println(resultSet.getObject(1));
           }

       } catch (Exception e) {
           e.printStackTrace();
       }finally{
           JDBCTools.release(preStatement, conn, resultSet);
       }
   }

}

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