readimagedemo.java

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package bigdata;

import java.sql.*;
import java.io.*;

public class ReadImageDemo {

  public static void main(String[] args) throws Exception {
    File file = null;
    FileOutputStream fileOutputStream = null;
    //定义数据库连接的驱动程序
    String driver = "org.gjt.mm.mysql.Driver";
    //定义MySQL数据库的连接地址
    String url = "jdbc:mysql://localhost:3306/EmployeeEBKC10";
    //声明byte数组，保存图片
    byte[] pictureBytes = null;
    //创建图片文件的名字数组
    String[] fileNames = {"./image/data01.jpg", "./image/data02.jpg", 
                          "./image/data03.jpg", "./image/data04.jpg", 
                          "./image/data05.jpg"};
    //声明连接类
    Connection conn;
    //声明SQL语句执行类
    Statement statement;
    //声明结果集类
    ResultSet resultSet = null;
    //注册SQLServer的JDBC驱动程序
    Class.forName(driver);
    //第一个参数定义用户名,第二个参数定义密码
    conn = DriverManager.getConnection(url, "root", "test");
    //创建SQL语句执行类
    statement = conn.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,
                                     ResultSet.CONCUR_READ_ONLY);
    String query = "select * from pictures";
    //取得数据集
    resultSet = statement.executeQuery(query);
    for(int i = 0; i < 5; ++i){
      //将数据集的游标移到相应的位置
      resultSet.absolute(i+1);
      //获取文件
      file = new File(fileNames[i]);
      //根据文件创建文件写出类
      fileOutputStream = new FileOutputStream(file);
      pictureBytes = resultSet.getBytes(3);
      //向文件写出图片数据
      fileOutputStream.write(pictureBytes);
      //保存文件
      fileOutputStream.close();
      System.out.println("成功创建图片文件" + fileNames[i] 
                         + ". 数据长度 = " + pictureBytes.length);
    }
    //关闭结果集
    resultSet.close();
    //关闭SQL语句执行类
    statement.close();
    //关闭数据库连接类
    conn.close();
  }
}