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Servlet上传文件

2024-07-01 21:37:29   228人阅读

Servlet上传文件


1、准备工作

（1）利用FileUpload组件上传文件，需要到apache上下载commons-fileupload-1.3.1.jar

         下载地址：http://commons.apache.org/fileupload/

（2）由于文件上传还得有IO流传输，需要到apache上下载commons-io-2.4.jar

         下载地址：http://commons.apache.org/io/


2、正式开发

（1）新建文件上传界面

        file.jsp：

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%  
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=http://www.mamicode.com/""> >
（2）新建文件上传成功界面
         result.jsp：
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%  
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=http://www.mamicode.com/""> >
（3）新建servlet进行文件上传处理
        FileUploadServlet.java：
package com.you.file.servlet;

import java.io.File;
import java.io.IOException;
import java.util.List;

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

import org.apache.commons.fileupload.FileItem;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;

public class FileUploadServlet extends HttpServlet 
{
	/**
	 * @Fields  serialVersionUID:
	 */
	private static final long serialVersionUID = -3788743064732005240L;
	
	/**
	 * The doPost method of the servlet. <br>
	 *
	 * This method is called when a form has its tag value method equals to post.
	 * 
	 * @param request the request send by the client to the server
	 * @param response the response send by the server to the client
	 * @throws ServletException if an error occurred
	 * @throws IOException if an error occurred
	 */
	public void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException 
	{
		/**
		 * 设置编码格式
		 */
		request.setCharacterEncoding("UTF-8");
		/**
		 * 创建一个工厂类
		 */
		DiskFileItemFactory factory = new DiskFileItemFactory();
		ServletContext context = getServletContext();  
		String path = context.getRealPath("/file");
		/**
		 * 设置上传文件放在磁盘上的临时目录
		 */
		factory.setRepository(new File(path));
		/**
		 * 设置上传文件大小
		 */
		factory.setSizeThreshold(1024*1024);
		
		//上传对象
		ServletFileUpload fileuplod = new ServletFileUpload(factory);
		try 
		{
			/**
			 * 解析各个表单域
			 */
			List<FileItem> list = fileuplod.parseRequest(request);
			
			for(FileItem item : list)
			{
				/**
				 * 判断是简单域 (item.isFormField()==true)
				 */
				if(item.isFormField())
				{
					//获得简单域的名字
					String fieldName = item.getFieldName();
					//获得简单域的值
					String fieldValue = http://www.mamicode.com/item.getString("UTF-8");>
（3）配置web.xml
<?xml version="1.0" encoding="UTF-8"?>
<web-app version="3.0" 
	xmlns="http://java.sun.com/xml/ns/javaee" 
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
	xsi:schemaLocation="http://java.sun.com/xml/ns/javaee 
	http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd">
  <display-name></display-name>
  <servlet>
    <description>This is the description of my J2EE component</description>
    <display-name>This is the display name of my J2EE component</display-name>
    <servlet-name>FileUploadServlet</servlet-name>
    <servlet-class>com.you.file.servlet.FileUploadServlet</servlet-class>
   
  </servlet>

  <servlet-mapping>
    <servlet-name>FileUploadServlet</servlet-name>
    <url-pattern>/FileUploadServlet</url-pattern>
  </servlet-mapping>
  
  <welcome-file-list>
    <welcome-file>index.jsp</welcome-file>
  </welcome-file-list>
</web-app>


3、过程演示
（1）初始化时


（2）输入用户名、密码，上传文件


（3）还未上传，项目中的file文件夹


（4）上传成功后，页面显示


（5）上传成功后，file文件夹


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