commons-fileupload文件上传、下载

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Servlet Java JSP JavaEE CSS

今天复习了下commons-fileupload文件上传，写了个demo。需要的jar包为：commons-fileupload-1.2.1.jar、commons-io-1.4.jar。都可去apache下的commons下下载。

一、上传

1、index.jsp

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<%@ 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>My JSP 'index.jsp' starting page</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="/commons-fileupload/UploadServlet" method="post" enctype="multipart/form-data">
            username:
            <input type="text" name="username">
            <br>
            password:
            <input type="password" name="password">
            <br>
            file1:
            <input type="file" name="file1">
            <br>
            file2:
            <input type="file" name="file2">
            <br>
            <input type="submit" value="submit">
        </form>
    </body>
</html>

2、UploadServlet.java

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package com.fileupload.servlet;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.List;

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;

@SuppressWarnings("serial")
public class UploadServlet extends HttpServlet {

    @SuppressWarnings({ "unchecked", "deprecation" })
    public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        request.setCharacterEncoding("UTF-8");
        //设置文件存储路径
        String path = request.getRealPath("/upload");
        //实例化工厂
        DiskFileItemFactory factory = new DiskFileItemFactory();
        //设置在内存中存储文件的的大小为1M，如果超出1M，将写入磁盘
        factory.setSizeThreshold(1024*1024);
        //如果文件超出1M，将写入磁盘
        factory.setRepository(new File(path));

        ServletFileUpload servletFileUpload = new ServletFileUpload(factory);
        try {
       //将request解析成FileItem,每个FileItem对应页面的一个输入对象。
        List<FileItem> list = servletFileUpload.parseRequest(request);
        for(FileItem item :list){
            if(item.isFormField()){//如果输入域是普通类型type=text（非file类型）
                String name = item.getFieldName();
                String value = item.getString("UTF-8");
                request.setAttribute(name, value);

            }else{//如果输入域是type=file类型

                String name = item.getFieldName();
                String value = item.getName();//将取到如下内容：eg：C:\Documents and Settings\liu\桌面\test.doc
                int start = value.lastIndexOf("\\");
                String fileName = value.substring(start+1);//解析成test.doc
                request.setAttribute(name, fileName);

//              //使用普通流写入文件
//              OutputStream out = new FileOutputStream(new File(path+"/"+fileName));
//              InputStream in = item.getInputStream();
//              byte buffer[]= new byte[1024];
//              int length = 0;
//              while((length=in.read(buffer))>0){
//                  out.write(buffer,0,length);
//              }
//              out.flush();
//              out.close();
//              in.close();

                //使用FileItem提供的方法，方便的输出
                item.write(new File(path+"/"+fileName));

            }
        }
        } catch (Exception e) {
            e.printStackTrace();
        }
        request.getRequestDispatcher("success.jsp").forward(request, response);
    }

}
3、success.jsp

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<%@ 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>My JSP 'success.jsp' starting page</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>
   username:${username }<br>
   password:${password }<br>
   file1:${file1 }<br>
   file2:${file2 }<br>



</body>
</html>

4、web.xml

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<?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>
    <servlet-name>UploadServlet</servlet-name>
    <servlet-class>com.fileupload.servlet.UploadServlet</servlet-class>
</servlet>

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

二：下载：

下载文件用一个Servlet完成:

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response.setContentType("text/html;charset=UTF-8");

        request.setCharacterEncoding("UTF-8");

        PrintWriter out = response.getWriter();

        Long id=Long.valueOf(request.getParameter("id"));

        FileInfo fileInfo=fileDAO.find(id);

response.setContentType("application/x-msdownload;");

//此行代码是防止中文乱码的关键！！

            response.setHeader("Content-disposition","attachment; filename="+new String(fileInfo.getName().getBytes("gb2312"),"iso8859-1"));

       BufferedInputStream bis=new BufferedInputStream(new FileInputStream(fileInfo.getPath()));

       BufferedOutputStream bos=new BufferedOutputStream(response.getOutputStream());

       //新建一个2048字节的缓冲区

       byte[] buff=new byte[2048];

       int bytesRead;

       while((bytesRead=bis.read(buff, 0, buff.length))!=-1)

       {

            bos.write(buff);

       }

        if (bis != null)

                bis.close();

            if (bos != null)

                bos.close();

    }

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2010-06-20 00:15
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