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java组件fileupload文件上传demo

2019年07月22日  | 移动技术网IT编程  | 我要评论

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。

常用的上传组件:  

    apache 的 commons fileupload

    javazoom的uploadbean

    jspsmartupload

fileupload下载地址

  

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

  

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

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>

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);
 }
}

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>

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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