完成文件上传下载功能案例

来源：互联网发布：不用网络的音乐播放器编辑：程序博客网时间：2024/06/05 01:05

上传的jsp页面（动态生成文件上传项）------------------------

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

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">

<html>

<head>

<title>My JSP 'upload2.jsp' starting page</title>

function addfile(){

var files=document.getElementById("files");

var input=document.createElement("input");

input.type="file";

input.name="file";

var deletebutton=document.createElement("input");

deletebutton.type="button";

deletebutton.value="删除";

deletebutton.onclick= function del(){

this.parentNode.parentNode.removeChild(this.parentNode);

}

var div=document.createElement("div");

div.appendChild(input);

div.appendChild(deletebutton);

files.appendChild(div);

}

</script>

</head>

<body>

<form action="UploadServlet" method="post"

enctype="multipart/form-data">

<table>

<tr>

<td>

上传用户：

</td>

<td>

</td>

</tr>

<tr>

<td>

</td>

</tr>

<tr>

</tr>

<tr>

</td>

</tr>

</table>

</form>

</body>

</html>

处理上传请求的servlet----------------------

package com.hbsi.servlet;

import java.io.File;

import java.io.FileOutputStream;

import java.io.IOException;

import java.io.InputStream;

import java.util.ArrayList;

import java.util.Arrays;

import java.util.List;

import java.util.UUID;

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.FileUploadBase;

import org.apache.commons.fileupload.FileUploadException;

import org.apache.commons.fileupload.ProgressListener;

import org.apache.commons.fileupload.disk.DiskFileItemFactory;

import org.apache.commons.fileupload.servlet.ServletFileUpload;

import com.sun.security.sasl.ServerFactoryImpl;

public class UploadServlet extends HttpServlet {

private List fileType=Arrays.asList("txt","jpg","bmp");

public void doGet(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

try {

//创建一个解析工厂

DiskFileItemFactory factory = new DiskFileItemFactory();

String tempPath=this.getServletContext().getRealPath("temp");

factory.setRepository(new File(tempPath));

//得到一个解析器

ServletFileUpload upload = new ServletFileUpload(factory);

upload.setHeaderEncoding("UTF-8");

//upload.setFileSizeMax(1024*1024);//限制大小

upload.setProgressListener(new ProgressListener() {

@Override

public void update(long pBytesRend, long pContentLength, int pItems) {

System.out.println("上传文件的大小为："+pContentLength+"，目前已上传了："+pBytesRend);

}

});

//将请求传入解析器，对请求进行解析

List<FileItem> list = upload.parseRequest(request);

//迭代list集合，得到每个输入项的数据

for (FileItem item : list) {

if (item.isFormField()) {

//普通输入项

String inputName = item.getFieldName();

String inputValue = item.getString("UTF-8");

System.out.println(inputName + ":" + inputValue);

} else {

//上传输入项

String fileName = item.getName();

if (!fileName.equals("")) {

fileName = fileName.substring(fileName

.lastIndexOf("\\") + 1);

//获取扩展名

/*String ext=fileName.substring(fileName.lastIndexOf(".")+1);

if(!fileType.contains(ext)){

request.setAttribute("message", "文件类型只能是txt，jpg，bmp");

request.getRequestDispatcher("/message.jsp").forward(request, response);

return;

}*/

String saveName=this.generateFileName(fileName);

InputStream in = item.getInputStream();

String savePath=this.getServletContext().getRealPath("WEB-INF/upload");

String savePaths = this.generateFilePath(savePath, fileName);

FileOutputStream out = new FileOutputStream(

savePaths+"\\" + saveName);

byte[] buf = new byte[1024];

int len = 0;

while ((len = in.read(buf)) > 0) {

out.write(buf, 0, len);

}

in.close();

out.close();

item.delete();

}

request.setAttribute("message", "上传成功");

}

}catch (FileUploadBase.FileSizeLimitExceededException e) {

request.setAttribute("message", "文件大小不能超过1M");

}

catch (Exception e) {

e.printStackTrace();

request.setAttribute("message", "上传失败");

}

request.getRequestDispatcher("/message.jsp").forward(request, response);

}

public String generateFileName(String filename){

return UUID.randomUUID().toString()+"_"+filename;

}

public String generateFilePath(String path,String filename){

int dir1 =filename.hashCode()& 0xf;

int dir2 =(filename.hashCode()>>4) &0xf;

String savePath = path+"\\"+dir1+"\\"+dir2;

File f = new File(savePath);

if(!f.exists()){

f.mkdirs();

}

return savePath;

}

public void doPost(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

doGet(request, response);

}

实现下载的servlet，显示文件列表------------------------

package com.hbsi.servlet;

import java.io.File;

import java.io.IOException;

import java.util.HashMap;

import java.util.Map;

import javax.servlet.ServletException;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

public class ListFileServlet extends HttpServlet {

public void doGet(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

//得到上传文件的文件夹

String savepath=this.getServletContext().getRealPath("/WEB-INF/upload");

Map map=new HashMap();

listFiles(new File(savepath),map);

request.setAttribute("map",map);

request.getRequestDispatcher("/listfile.jsp").forward(request, response);

}

private void listFiles(File file,Map map){

if(file.isFile()){

String uuidname=file.getName();

String realname=uuidname.substring(uuidname.indexOf("_")+1);

map.put(uuidname,realname);

}else{

File[] files=file.listFiles();

for(File f:files){

listFiles(f,map);

}

public void doPost(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

doGet(request, response);

}

下载的文件jsp页面--------------------------

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

<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">

<html>

<head>

<title>My JSP 'listfile.jsp' starting page</title>

</head>

<body>

<c:forEach var="me" items="${map}">

<c:url var="url" value="/DownloadServlet">

<c:param name="filename" value="${me.key}"></c:param>

</c:url>

文件名： ${me.value}<a href="${url}">下载</a>

<br>

</c:forEach>

</body>

</html>

处理下载请求的servlet-----------------

package com.hbsi.servlet;

import java.io.File;

import java.io.FileInputStream;

import java.io.IOException;

import java.io.OutputStream;

import java.net.URLEncoder;

import javax.servlet.ServletException;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

public class DownloadServlet extends HttpServlet {

public void doGet(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

String filename=request.getParameter("filename");

filename=new String(filename.getBytes("iso8859-1"), "UTF-8");

//找到文件所在文件夹位置

// String savepath=this.getFileSavePath(filename);//现在的文件名是uuid的

String savepath = this.getFileSavePath(this.getRealName(filename));//现在的文件名是uuid的

File f=new File(savepath+"\\"+filename);

if(!f.exists()){

request.setAttribute("message","你下载的资源不存在");

request.getRequestDispatcher("/message.jsp").forward(request, response);

}

response.setHeader("content-disposition","attachment;filename="+URLEncoder.encode(this.getRealName(filename),"UTF-8"));

FileInputStream in = new FileInputStream(f);

byte[] buf = new byte[1024];

int len=0;

OutputStream out = response.getOutputStream();

while((len=in.read(buf))>0){

out.write(buf,0,len);

}

in.close();

}

public String getFileSavePath(String filename){

int dir1 = filename.hashCode()&0xf;

int dir2 = (filename.hashCode()>>4)&0xf;

String savepath = this.getServletContext().getRealPath("/WEB-INF/upload")+"\\"+dir1+"\\"+dir2;

return savepath;

}

public String getRealName(String filename){

String realName=filename.substring(filename.indexOf("_")+1);

return realName;

}

public void doPost(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

doGet(request, response);

}

显示上传下载成功与否的jsp--------------------------

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

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">

<html>

<head>

<title>My JSP 'message.jsp' starting page</title>

</head>

<body>

${message}

</body>

</html>