JavaWeb之文件上传

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1.上传组件

①Apache的Commons FileUpload

②JavaZoom的UploadBean

③JspSmartUpload

2.下载Commons的FileUpload组件

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

同时还要下载Commons的IO组件

地址:http://commons.apache.org/io/

3.使用实例

步骤一：创建文件上传的页面：fileUpload.jsp

注意表单的 enctype 属性，这个设置很重要，详情请见：http://www.cnblogs.com/yinger/archive/2011/09/11/2173689.html

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html>  <head>    <title>文件上传</title>  </head>  <body>      <form action="<%=request.getContextPath() %>/servlet/FileUploadServlet" method="post" enctype="multipart/form-data" >        上传人名:<input type="text" name="name" /><br/>                上传文件:<input type="file" name="file" /><br/>          <input type="submit" name="submit" value="提交" />      </form>  </body></html>

步骤二：创建处理文件上传的servlet：fileUploadServlet

package com.yinger.servlet;import java.io.File;import java.io.IOException;import java.util.Iterator;import java.util.List;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.disk.DiskFileItemFactory;import org.apache.commons.fileupload.servlet.ServletFileUpload;public class FileUploadServlet extends HttpServlet {        private ServletContext sc;    private String savePath;    private static final long serialVersionUID = 151650843430214502L;    public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {        doPost(request, response);    }    public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {                request.setCharacterEncoding("UTF-8");            DiskFileItemFactory factory = new DiskFileItemFactory();        ServletFileUpload servletFileUpload = new ServletFileUpload(factory);//通过工厂生成一个处理文件上传的servlet对象                try {            List items = servletFileUpload.parseRequest(request);//解析request            Iterator iterator = items.iterator();            while (iterator.hasNext()) {                FileItem item = (FileItem) iterator.next();                if(item.isFormField()){//表单的参数字段                    System.out.println("表单的参数名称："+item.getFieldName()+",表单的参数值："+item.getString("UTF-8"));                }else {                    if(item.getName()!=null && !item.getName().equals("")){//一个上传的文件                        System.out.println("文件的名称："+item.getName());                        System.out.println("文件的大小："+item.getSize());                        System.out.println("文件的类型："+item.getContentType());                                                File tempFile = new File(item.getName());//getName得到的文件名称包含了它在客户端的路径                        File file = new File(sc.getRealPath("/")+savePath,tempFile.getName());                        item.write(file);//将上传的文件写入到file中                                                request.setAttribute("message", "上传文件成功！");                    }else{                        request.setAttribute("message", "没有选择上传文件！");                    }                }            }        } catch (Exception e) {            e.printStackTrace();            request.setAttribute("message", "上传文件失败！");        }                request.getRequestDispatcher("/fileUploadResult.jsp").forward(request, response);//转向，输出结果    }    @Override    public void init(ServletConfig config) throws ServletException {        savePath = config.getInitParameter("savePath");        sc = config.getServletContext();            }    }

步骤三：修改web.xml

<?xml version="1.0" encoding="UTF-8"?><web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web=http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd

xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" version="2.5">  <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.yinger.servlet.FileUploadServlet</servlet-class>    <init-param> <!-- Servlet的初始化参数，配置上传文件的保存路径，这里是当前应用的uplods目录下 -->    <param-name>savePath</param-name>    <param-value>uploads</param-value>    </init-param>  </servlet>  <servlet-mapping>    <servlet-name>FileUploadServlet</servlet-name>    <url-pattern>/servlet/FileUploadServlet</url-pattern>  </servlet-mapping>  <welcome-file-list>    <welcome-file>index.jsp</welcome-file>  </welcome-file-list></web-app>

同时在项目的根目录下创建文件夹 uploads （可以就在WebRoot中创建）

步骤四：创建显示上传结果的页面：fileUploadResult.jsp

<%@ page language="java" pageEncoding="UTF-8"%><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html>  <head>    <title>文件上传</title>  </head>  <body>  <p>      ${requestScope['message'] }<br/>  </p>  </body></html>