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Servlet上传文件

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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="<%=basePath%>"> 
    
    <title>上传文件前</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">
	

  </head>
  
  <body>
    <form action="FileUploadServlet" method="post" enctype="multipart/form-data">
        <table>
           <tr>
             <td>
                <label for="username">用户名:</label>
            	<input type="text" name="username"/>
             </td>
           </tr>
           <tr>
             <td>
               <label for="password">密  码:</label>
           	   <input type="password" name="password"/>
             </td>
           </tr>
           <tr>
             <td>
                       
               <input type="file" name="fileOne" id="fileOne"/>
             </td>
           </tr>
           <tr>
             <td>
                       
               <input type="file" name="fileTwo" id="fileTwo"/>
             </td>
           </tr>
           <tr>
              <td>
                        
                <input type="submit" name="submit" id="submit" value="提交"/>
                     
                <input type="reset" name="reset" id="reset" value="重置"/>
              </td>
           </tr>
        </table>
    </form>
  </body>
</html>

(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="<%=basePath%>"> 
    <title>上传文件成功</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">
	

  </head>
  
  <body>
         用户名:<%= request.getAttribute("username") %><br/>  
	密  码:<%= request.getAttribute("password") %><br/>  
	文件一:<%= request.getAttribute("fileOne") %><br/>  
	文件二:<%= request.getAttribute("fileTwo") %><br/>  
  </body>
</html>

(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 = item.getString("UTF-8");
					request.setAttribute(fieldName, fieldValue);
				}
				else//判断是文件域 (item.isFormField()==false)
				{
					//获得文件域的名字
					String fieldName = item.getFieldName();
					//获得文件域的值,带路径,即是路径+文件名
					String value = item.getName();
					//取的文件域的值的名字,不带路径
					int temp = value.lastIndexOf("\\");
					String fieldValue = value.substring(temp+1);
					//获得是file文件的内容
					request.setAttribute(fieldName, fieldValue);
					
					//写入
					item.write(new File(path,fieldValue));
				}
			}
		} 
		catch (Exception e) 
		{
			//e.printStackTrace();
		}
		/**
		 * 跳转到上传成功界面
		 */
		request.getRequestDispatcher("result.jsp").forward(request, response);
	}
	
	/**
	 * Initialization of the servlet. <br>
	 * init方法
	 * @throws ServletException if an error occurs
	 */
	public void init() throws ServletException 
	{
		
	}
	
	/**
	 * destroy方法
	 * Destruction of the servlet. <br>
	 */
	public void destroy() 
	{
		super.destroy(); 
	}
	
	/**
	 * The doGet method of the servlet. <br>
	 *
	 * This method is called when a form has its tag value method equals to get.
	 * doGet方法
	 * @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 doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException 
	{
		this.doPost(request, response);
	}
}

(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

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(2)输入用户名、密码,上传文件

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(3)还未上传,项目中的file文件夹

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(4)上传成功后,页面显示

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(5)上传成功后,file文件夹

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Servlet上传文件,布布扣,bubuko.com

Servlet上传文件

原文:http://blog.csdn.net/you23hai45/article/details/24576445

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