往MYSQL中插入，读写图片!

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开发环境：MyEclipse+MySql

1，随便找一个数据库建一张表，我这里用的是mysql数据库，

（1）切换到mysql数据库：use mysql;

（2）建表create table image(

name char(20) not null primary key,

image longblob

);

PS:注意存放图片那个字段的类型，为longblob，把name这个字段设置成主键，以防后面插入图片发生错误！

（3）然后我们插入名字，方便查找

insert into image (name) value ('image');

2,其实很简单，只有三个文件：

UploadImage.java：负责将图片存入数据库

showImage.jsp：负责将图片从数据库中读出来

index.jsp：负责显示，插入图片等操作

先上效果图：

然后咱们来看整个项目的大体框架：

闲话少说,上代码：

UploadImage.java

public class UploadImage {String userName="root";String password="123456";Connection conn=null;Statement stmt=null;String url="jdbc:mysql://localhost:3306/mysql";public boolean storeImage(String path,String sql) {try {File file = new File(path);//打开文件FileInputStream fin = new FileInputStream(file);//建一个缓冲保存数据ByteBuffer nbf = ByteBuffer.allocate((int) file.length());byte[] array = new byte[1024];int offset = 0, length = 0;//读存数据while ((length = fin.read(array)) > 0) {if (length != 1024)nbf.put(array, 0, length);elsenbf.put(array);offset += length;}//关闭文件fin.close();//新建一个数组保存要写的内容byte[] content = nbf.array();//保存数据return setImage(sql, content);} catch (FileNotFoundException e) {e.printStackTrace();} catch (IOException e) {e.printStackTrace();}//如果发生文件读写错误都会返回falsereturn false;}private boolean setImage(String sqlstr, byte[] in) {boolean flag = false;if (sqlstr == null)sqlstr = "select * from image";try {Class.forName("com.mysql.jdbc.Driver");conn=DriverManager.getConnection(url,userName,password);stmt =conn.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,ResultSet.CONCUR_UPDATABLE);ResultSet rs = stmt.executeQuery(sqlstr);if (rs.next()) {rs.updateBytes(2, in);        //2表示更新第二个字段，即image这个字段rs.updateRow();} else {rs.moveToInsertRow();rs.updateBytes(2, in);rs.insertRow();}rs.close();flag = true;} catch (Exception e) {e.printStackTrace();}return flag;}}

由于JSP一直提倡java代码与jsp页面分离，java代码负责逻辑控制，jsp页面负责显示，所以我们只要我们在jsp页面调用上面那个类即可，这样jsp页面看起来就非常干净整洁！

showImage.jsp

<%@ page language="java" contentType="image/jpeg;charset=GB2312"%><%@ page import="java.io.*"%><%@ page import="java.sql.*"%><%@ page import="java.awt.image.*"%><%@ page import="javax.imageio.*"%><%@ page import="com.sun.image.codec.jpeg.*"%><html>    <head>    <meta http-equiv="Content-Type" content="image/jpeg; charset=GB2312">    <title>showDBImage.jsp</title>  </head>  <body><%String userName="root";String password="123456";Connection conn=null;String url="jdbc:mysql://localhost:3306/mysql";String showImage = "select * from image where name='image';" ;BufferedInputStream inputImage = null;try{Class.forName("com.mysql.jdbc.Driver");conn=DriverManager.getConnection(url,userName,password);Statement st = conn.createStatement();ResultSet rs=st.executeQuery(showImage);while(rs.next()) {Blob blob = (Blob)rs.getBlob("image");inputImage = new BufferedInputStream(blob.getBinaryStream()); }  BufferedImage image = null;  image=ImageIO.read(inputImage);ServletOutputStream sos = response.getOutputStream();JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(sos);encoder.encode(image);inputImage.close();} catch(SQLException se) {se.printStackTrace();} catch(IOException ie) {ie.printStackTrace();}%>    </body></html>

index.jsp

<%@ page language="java" import="java.util.*,com.njue.image.*" pageEncoding="gb2312"%><%String path = request.getContextPath();String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";%><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html>  <head>    <base href="<%=basePath%>">        <title>My JSP 'index.jsp' starting page</title><meta http-equiv="pragma" content="no-cache"><meta http-equiv="cache-control" content="no-cache"><meta http-equiv="expires" content="0">    <meta http-equiv="keywords" content="keyword1,keyword2,keyword3"><meta http-equiv="description" content="This is my page"><!--<link rel="stylesheet" type="text/css" href="styles.css">--><script language="javascript" type="text/javascript">    function login(){          var path=document.getElementById("file");         path.select();     var realpath = document.selection.createRange().text;   if(realpath!=null&&realpath.length>0){var r=confirm("你确定将这张图片存入MYSQL数据库吗？");  if(r==true){window.location="index.jsp?realpath="+realpath;}}else{alert("没有选择图片！");}}</script>  </head>    <body background="background.jpg">    <div align="center" style="margin-top:15%;">    <%       String realpath=request.getParameter("realpath");       if(realpath!=null&&realpath.length()>0){       String sql="select * from image where name='image';";       UploadImage image=new UploadImage();       if(image.storeImage(realpath,sql)){     %>     <h1>成功插入图片！</h1><br>     <img src="showImage.jsp"/><br><br>     <%     }     else{     %>      <h1>插入图片失败！</h1>     <%     }     }      %>    <input type="file" name="file"/>    <a href=javascript:login()>确定</a>    </div>  </body></html>

把我期间遇到的问题列出来：

1，javax.servlet.ServletException: java.lang.NoClassDefFoundError: org/aspectj/lang/Signature

如果出现这个错误，多半是mysql的驱动有问题了

mysql-connector-java-3.1.10-bin.jar

mysql-connector-java-3.1.10-bin-g.jar

大家可以看出一个后面有-g,一个没有，这里大家应该用第一个，将他复制进WebRoot/WEB-INF/lib这个文件夹中即可,

有兴趣的可以下载整个工程！

下载地址：http://download.csdn.net/detail/pzhtpf/4177978