Java Web 文件上传

来源:转载

在我们的web开发中,很多的时候都需要把本机的一些文件上传到web服务器上面去

如:一个BBS系统,当用户使用这是系统的时候,能把本机的一些图片,文档上传到服务器

上面去。然后其他用户可以去下载这些文件,那么这样的话,我们可以自己编程实现文件的上传

但是更好的方式是使用一些已有的组件帮助我们实现这种上传功能。

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常用的上传组件:

Apache 的 Commons FileUpload

JavaZoom的UploadBean

jspSmartUpload

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FileUpload下载地址:

http://commons.apache.org/fileupload/

下载:commons-fileupload-1.2.2-bin.zip    得到:commons-fileupload-1.2.2.jar

http://commons.apache.org/io/

下载:commons-io-1.4-bin.zip       得到:commons-io-1.4.jar

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upload.jsp

代码;

<%@ page language="java" contentType="text/html; charset=UTF-8"%>

<html>

<head>

<title>using commons Upload to upload file </title>

</head>

<style>

* { font-family: "宋体"; font-size: 14px }</style>
<body>
<p align="center"> 请您选择需要上传的文件</p>
<form id="form1" name="form1" method="post" action="servlet/fileServlet" enctype="multipart/form-data">
 <table border="0" align="center">
  <tr>
   <td>上传人:</td>
   <td>
    <input name="name" type="text" id="name" size="20" ></td>
  </tr>  
  <tr>
   <td>上传文件:</td>
   <td><input name="file" type="file" size="20" ></td>
  </tr>    
  <tr>   
   <td></td><td>
    <input type="submit" name="submit" value="提交" >
    <input type="reset" name="reset" value="重置" >
   </td>
  </tr>
 </table>
</form>
</body>
</html>

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FileUploadServlet.java

代码:

/**
 *
 */
package com.b510.example;

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


import javax.servlet.ServletConfig;
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.FileUploadException;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;

/**
 *
 * @author XHW
 *
 * @date 2011-7-26
 *
 */
public class FileUploadServlet extends HttpServlet {

 private static final long serialVersionUID = -7744625344830285257L;
 private ServletContext sc;
 private String savePath;

 public void doGet(HttpServletRequest request, HttpServletResponse response)
   throws ServletException, IOException {
  doPost(request, response);
 }
 

 public void init(ServletConfig config) {
  // 在web.xml中设置的一个初始化参数
  savePath = config.getInitParameter("savePath");
  sc = config.getServletContext();
 }
 
 public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
  request.setCharacterEncoding("UTF-8");
  DiskFileItemFactory factory = new DiskFileItemFactory();
  ServletFileUpload upload = new ServletFileUpload(factory);
  try {
   List items = upload.parseRequest(request);
   Iterator itr = items.iterator();
   while (itr.hasNext()) {
    FileItem item = (FileItem) itr.next();
    if (item.isFormField()) {
     System.out.println("表单参数名:" + item.getFieldName() + ",表单参数值:" + item.getString("UTF-8"));
    } else {
     if (item.getName() != null && !item.getName().equals("")) {
      System.out.println("上传文件的大小:" + item.getSize());
      System.out.println("上传文件的类型:" + item.getContentType());
      // item.getName()返回上传文件在客户端的完整路径名称
      System.out.println("上传文件的名称:" + item.getName());

      File tempFile = new File(item.getName());

//上传文件的保存路径
      File file = new File(sc.getRealPath("/") + savePath, tempFile.getName());
      item.write(file);
      request.setAttribute("upload.message", "上传文件成功!");
     }else{
      request.setAttribute("upload.message", "没有选择上传文件!");
     }
    }
   }
  }catch(FileUploadException e){
   e.printStackTrace();
  } catch (Exception e) {
   e.printStackTrace();
   request.setAttribute("upload.message", "上传文件失败!");
  }
  request.getRequestDispatcher("/uploadResult.jsp").forward(request, response);
 }
}

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uploadResult.jsp

代码;

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
  <head>
   
    <title>uploadResult</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">
 -->

  </head>
 
  <body>
  ${requestScope['upload.message'] }
    <a href="/upload/uploadFile.jsp">上传文件</a>
  </body>
</html>

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web.xml

代码:

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.5"
 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_2_5.xsd">
  <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.b510.example.FileUploadServlet</servlet-class>

<!--设置初始化参数-->
    <init-param>
     <param-name>savePath</param-name>
     <param-value>uploads</param-value>
    </init-param>
  </servlet>

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


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