Mysql 数据库创建图片记录

最新推荐文章于 2021-03-18 00:13:19 发布

最新推荐文章于 2021-03-18 00:13:19 发布 · 549 阅读

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本文介绍了一个Java后台servlet实现从MySQL数据库中读取图片，并将其展示在前端JSP页面上的具体实现方法。该示例代码展示了如何使用PreparedStatement插入图片到数据库，以及如何通过ResultSet从数据库中检索图片并发送到客户端。

后台servlet：


package com;

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

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;


public class GetImage extends HttpServlet {

	public void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {

		Connection con = null;
		try {
			Class.forName("com.mysql.jdbc.Driver").newInstance();
			String URL = "jdbc:mysql://localhost:3306/test?user=root&password=root";
			con = DriverManager.getConnection(URL);
			Statement stmt = con.createStatement();

			/*
			 * create a BLOB record in Mysql database.
			 * */
//			PreparedStatement st = null;
//			File file = new File("d:\\tom.jpg");
//			InputStream in = new BufferedInputStream(new FileInputStream(file));
//			String sql = "insert into image(Image) values(?)";
//			st = con.prepareStatement(sql);
//			st.setBinaryStream(1, in, (int) file.length());
//			int i = st.executeUpdate();
//			in.close();

			/*
			 * Retrieve the image from database
			 * */
			String sql = "select * from image where Id = 2";
			ResultSet rs = stmt.executeQuery(sql);
			if (rs.next()) {
				Blob b = rs.getBlob("Image");
				long size = b.length();
				byte[] bs = b.getBytes(1, (int) size);
				response.setContentType("image/jpeg");
				OutputStream outs = response.getOutputStream();
				outs.write(bs);
				outs.flush();
				rs.close();
			}
		}catch(Exception e){
			e.printStackTrace();
		} finally {
			try {
				con.close();
			} catch (SQLException e) {
				e.printStackTrace();
			}
		}
	}

}

web.xml中的配置信息：


  <servlet>
    <servlet-name>GetImage</servlet-name>
    <servlet-class>com.GetImage</servlet-class>
  </servlet>
  <servlet-mapping>
    <servlet-name>GetImage</servlet-name>
    <url-pattern>/GetImage.jsp</url-pattern>
  </servlet-mapping>

前台jsp中的code：


   <img src="GetImage.jsp">

SQL脚本：


CREATE TABLE `image` (                   
          `Id` int(11) NOT NULL auto_increment,  
          `Image` blob,                          
          PRIMARY KEY  (`Id`)                    
        ) ENGINE=InnoDB DEFAULT CHARSET=latin1