2023年11月28日发(作者：)本文将阐述怎么使用commons-fileupload将图片上传至mysql数据库，并利用java servlet将其在浏览器中显示
出来。
前提条件：
正确安装了mysql,tomcat,并下载了。
1，前台页面
---test_---
2，上传的后台处理页面
------
<%@ page contentType="text/html; charset=gb2312" %>
<%@ page import=".*" %>
<%@ page import=".*"%>
<%@ page import=".*"%>
<%@ page import="load.*" %>
<%@ page import="pulate" %>
<%
DiskFileUpload upload=new DiskFileUpload();
eThreshold(4096);
ositoryPath("d:/java/");
eMax(10000000);
List fileItems = equest(request);
Iterator i = or();
String name = ((FileItem)()).getString();
FileItem fi = (FileItem)();
String fileName = e();
//n(fileName);
fileName = e(':");
(getBlob(id));
();
();
}
public byte[] getBlob(int photoid){
String sql="select image from photo where id=?";
//(sql);
Blob blob=null;
byte[] bytes=null;
//String description="";
PreparedStatement pstmt=null;
ResultSet rs=null;
DbManipulate mydb=new DbManipulate();
try{
pstmt=y(sql);
(1,photoid);
rs=eQuery();
while(()){
blob=b(1);
}
bytes=es(1,(int)(()));
}catch(SQLException e){}
return bytes;
}
}
4，存储图片的表定义：
create database web_exam;
use web_exam;
create table photo(
id int not null auto_increment primary key,
image mediumblob not null,
description varchar(100) null
);
5，应用程序的目录结构
%catalina_home%webappsdemo
------test_
------
------WEB-INF
|----
|-----
|-----lib
|-------
|-------
|----src
|----com
|-----cf
|-----photo
|-----
|-----model
|----
|----
|----
6，文件内容
PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
"/j2ee/dtds/web-app_2_">
7，ant的buildfile内容
------------
8，
package ;
public interface DbConst{
public final static String JDBC_DRIVER="";
public final static String JDBC_URL="jdbc:mysql://localhost:3306/web_exam?"
+"useUnicode=true&characterEncoding=GB2312";
public final static String JDBC_USER="root";
public final static String JDBC_PASS="chenfu";
}
9，
package ;
import .*;
public class DbConnection implements DbConst{
private String jdbcDriver=JDBC_DRIVER;
private String databaseURL=JDBC_URL;
private String dbUsername=JDBC_USER;
private String dbPassword=JDBC_PASS;
private Connection con=null;
public String getJdbcDriver(){
return iver;
}
public void setJdbcDriver(String d){
iver=d;
}
public String getDatabaseURL(){
return seURL;
}
public void setDatabaseURL(String url){
seURL=url;
}
public String getDbUsername(){
return name;
}
public void setDbUsername(String u){
name=u;
}
public String getDbPassword(){
return word;
}
public void setDbPassword(String p){
word=p;
}
public boolean isConnected(){
return (con!=null);
}
public void disconnected(){
if(con!=null){
try
{
();
}
catch (SQLException ignore)
{
}
finally {
con=null;
}
}
}
public void setCon(Connection c){
=c;
}
public Connection getCon() throws SQLException{
if(isConnected()) throw new SQLException("Already connected");
if(jdbcDriver==null) throw new SQLException("No jdbcDriver property");
if(databaseURL==null) throw new SQLException("No jdbcURL property");
try
{
e(jdbcDriver);
//(jdbcDriver);
}
catch (ClassNotFoundException e)
{
throw new SQLException(jdbcDriver+"class could not loaded");
}
con=nection(databaseURL,dbUsername,dbPassword);
return con;
}
}
10，
package ;
import .*;
public class DbManipulate{
private Connection con=null;
private PreparedStatement pstmt=null;
public PreparedStatement DbQuery(String sql)throws SQLException{
DbConnection newcon=new DbConnection();
con=();
pstmt=eStatement(sql,
_SCROLL_SENSITIVE,_READ_ONLY);
//(sql);
return pstmt;
}
public PreparedStatement DbUpdate(String sql)throws SQLException{
DbConnection newcon=new DbConnection();
con=();
pstmt=eStatement(sql);
return pstmt;
}
public void DbClose(){
if(pstmt!=null){
pstmt=null;
}
}
}
11，转到该web application的WEB-INF下，在命令行中执行ant，以编译源文件，然后打开tomcat服务器，
在浏览器中打开地址：localhost:8080/demo/tes
t_,试着去上传一张jpg的图片,看看行不行。
12，欢迎大家提出宝贵意见，请联系我：
email:cf0124@
msn:cf_asp_master@
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