将以Blob类型存在数据库的图片保存在本地

本文以JDBC格式将blob类型存在SQLserver数据库的图片导出到本地

package com.wenhua.dl_guihua.action;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.sql.Blob;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

public class TestPic {
	// 定义 DM JDBC 驱动串
	String jdbcString = "com.microsoft.sqlserver.jdbc.SQLServerDriver";
	// 定义 DM URL 连接串
	String urlString = "jdbc:sqlserver://192.168.1.203:1433; DatabaseName=DL";
	// 定义连接用户名
	String userName = "sa";
	// 定义连接用户口令
	String password = "root";
	// 定义连接对象
	static Connection conn = null;

	static Statement stmt = null;
	static PreparedStatement ps = null;
	static ResultSet rs = null;

	/*
	 * 加载 JDBC 驱动程序
	 * 
	 * @throws SQLException 异常
	 */

	public void loadJdbcDriver() throws SQLException {
		try {
			System.out.println("Loading JDBC Driver...");
			// 加载 JDBC 驱动程序
			Class.forName(jdbcString);
		} catch (ClassNotFoundException e) {
			throw new SQLException("Load JDBC Driver Error1: " + e.getMessage());
		} catch (Exception ex) {
			throw new SQLException("Load JDBC Driver Error : " + ex.getMessage());
		}
	}

	public void connect() throws SQLException {
		try {
			System.out.println("Connecting to DM Server...");
			// 连接 DM 数据库
			conn = DriverManager.getConnection(urlString, userName, password);
			System.out.println("数据库连接成功！");
		} catch (SQLException e) {
			throw new SQLException("Connect to DM Server Error : " + e.getMessage());
		}
	}

	/*
	 * 关闭连接
	 * 
	 * @throws SQLException 异常
	 */

	public void disConnect() throws SQLException {
		try {
			// 关闭连接
			conn.close();
			System.out.println("close");
		} catch (SQLException e) {
			throw new SQLException("close connection error : " + e.getMessage());
		}
	}

	public static void main(String args[]) throws IOException, SQLException {

		TestPic basicApp = new TestPic();
		// 加载驱动程序
		basicApp.loadJdbcDriver();

		basicApp.connect();

		// 读取图片出来，保存到本地的磁盘上面
//		String sql = "SELECT * FROM ManagementWeb_Information_pic";
		String sql = "SELECT * FROM test";
		ps = conn.prepareStatement(sql);
		rs = ps.executeQuery();
		String s1 = "";
		//将图片存放到本地的路径
		String s = "E:\\工作专用\\大连规划\\图片分类\\信息动态\\综合信息\\";
		while (rs.next()) {
			System.out.println("图片名: " + rs.getInt("id")+ "_" + rs.getInt("info_id")+"_"+ rs.getString("title")+".jpg");
			Blob blob = rs.getBlob("pic");
			if(blob == null){
				continue;
			}
			//验证图片路径是否存在，不存在就创建
			File f = new File(s);
			if(!f.exists()){
				f.mkdirs();
			}
			
			s1 = s + rs.getInt("id")+ "_" + rs.getInt("info_id")+"_"+ rs.getString("title").replace("\"", "")+".jpg";
			File file2 = new File(s1);
			OutputStream outputStream = new FileOutputStream(file2);
			try {
				//blob.getBytes的第一个参数是从第几个字节开始提取数据，第二个是提取字节的长度
				outputStream.write(blob.getBytes(1, (int) blob.length()));
			} catch (IOException e) {
				e.printStackTrace();
			}

		}

		basicApp.disConnect();
		System.out.println("数据库连接关闭");
	}
}