往MYSQL中插入，读写图片!

谁践踏了优雅 2021-07-05 00:32 442阅读 0赞

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：

![1332854500_7239.PNG][]![1332854525_2992.PNG][]

然后咱们来看整个项目的大体框架：

![1332854465_7787.PNG][]

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);
    				else
    					nbf.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false
    		return 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">
    	
    	<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][http_download.csdn.net_detail_pzhtpf_4177978]**

[1332854500_7239.PNG]: https://img-my.csdn.net/uploads/201203/27/1332854500_7239.PNG
[1332854525_2992.PNG]: https://img-my.csdn.net/uploads/201203/27/1332854525_2992.PNG
[1332854465_7787.PNG]: https://img-my.csdn.net/uploads/201203/27/1332854465_7787.PNG
[http_download.csdn.net_detail_pzhtpf_4177978]: http://download.csdn.net/detail/pzhtpf/4177978