实现文件上传和下载功能代码,Java代码库,德仔网

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【Java】实现文件上传和下载功能
作者:xychenqiang / 发布于2015/8/10/ 520

	FileUploadServlet.java

	package upload;
	
	import java.io.File;
	import java.io.FileOutputStream;
	import java.io.IOException;
	import java.io.InputStream;
	import java.io.OutputStream;
	
	
	/**
	* 上传文件
	*/
	import java.io.PrintWriter;
	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.FileUploadException;
	import org.apache.commons.fileupload.disk.DiskFileItemFactory;
	import org.apache.commons.fileupload.servlet.ServletFileUpload;
	
	import exception.FileSizeException;
	import exception.FileTypeException;
	
	import util.WebUtil;
	
	public class FileUploadServlet extends HttpServlet {
	
	
	
	 public void doGet(HttpServletRequest request, HttpServletResponse response)
	 throws ServletException, IOException {
	
	 }
	
	
	 public void doPost(HttpServletRequest request, HttpServletResponse response)
	 throws ServletException, IOException {
	
	 try {
	 //通知浏览器以UTF-8的方式来解码
	 request.setCharacterEncoding("UTF-8");
	 //创建上传文件的工厂
	 DiskFileItemFactory factory = new DiskFileItemFactory();
	 //设置上传文件的临时缓存区为100k
	 factory.setSizeThreshold(100*1024);
	 //定位临时目录的路径，这里的/表示当前Web应用的根目录
	 String tempPath = this.getServletContext().getRealPath("/WEB-INF/temp");
	 //设置上传文件超过100K的临时目录存放点
	 factory.setRepository(new File(tempPath));
	 //创建上传文件对象（核心）
	 ServletFileUpload fileUpload = new ServletFileUpload(factory);
	 //判断客户端是否已RCF协议的方式上传
	 if(fileUpload.isMultipartContent(request)){
	 //解析request对象中的表单字段
	 List<FileItem> fileItemList = fileUpload.parseRequest(request);
	 //迭代
	 for(FileItem fileItem : fileItemList){
	 //如果是普通字段
	 if(fileItem.isFormField()){
	 String fileName = fileItem.getFieldName();
	 String fileNameValue = fileItem.getString("UTF-8");
	 //显示
	 System.out.println(fileName + ":" + fileNameValue);
	 }else if(!fileItem.isFormField()){
	 //获取上传文件的名字
	 String filename = fileItem.getName();
	 //获得UuidFileName
	 String uuidFileName = WebUtil.makeUuidFileName(filename);
	 System.out.println(uuidFileName);
	 //定位上传文件的存放的目录
	 String uploadPath = this.getServletContext().getRealPath("/WEB-INF/upload");
	 //获取上传文件存放的子目录
	 String subUploadPath = WebUtil.subUploadPath(uploadPath,uuidFileName);
	 //获取上传文件的大小
	 long size = fileItem.getSize();
	 //如果上传文件超过200K
	 if(size>200*1024){
	 //人工抛出异常
	 throw new FileSizeException();
	 }
	 //获取上传文件的类型
	 String contentType = fileItem.getContentType();
	 //如果上传的文件类型不是JPG格式
	 if(!"image/jpeg".equals(contentType)){
	 //人工抛出异常
	 throw new FileTypeException();
	 }
	
	
	
	
	 //调用工具类的方法writeToFiel
	 WebUtil.writeToFile(fileItem, subUploadPath, uuidFileName);
	
	 /*//获取上传文件输入流
	 InputStream is = fileItem.getInputStream();
	 //定位文件输出流
	 OutputStream os = new FileOutputStream(new File(uploadPath + "/" + name));
	 //将上传文件写入指定的目录下
	 byte[] buf = new byte[2048];
	 int len = 0;
	 while((len = is.read(buf))>0){
	 os.write(buf,0,len);
	 }
	 os.close();
	 is.close();
	 */
	 //把临时文件删除
	 fileItem.delete();
	 }
	 }
	 request.setAttribute("message", "<font style = 'font-size:111ps;color:red'>上传成功</font>");
	 request.getRequestDispatcher("/WEB-INF/message.jsp").forward(request, response);
	 }else{
	 request.setAttribute("message", "<font style = 'font-size:111px;color:red'>上传文件必须采用RFC协议指定的格式</font>");
	 request.getRequestDispatcher("/WEB-INF/message.jsp").forward(request, response);
	 }
	 }
	 //上传文件的大小不能超过200K
	 catch (FileSizeException e) {
	 e.printStackTrace();
	 request.setAttribute("message", "<font style = 'font-size:111ps;color:red'>上传文件失败！上传文件不能超过200K</font>");
	 request.getRequestDispatcher("/WEB-INF/message.jsp").forward(request, response);
	 }
	 //上传文件必须为图片类型
	 catch (FileTypeException e) {
	 e.printStackTrace();
	 request.setAttribute("message", "<font style = 'font-size:111ps;color:red'>上传文件失败！上传文件必须是图片类型的</font>");
	 request.getRequestDispatcher("/WEB-INF/message.jsp").forward(request, response);
	 }
	 catch (Exception e) {
	 e.printStackTrace();
	 request.setAttribute("message", "<font style = 'font-size:111ps;color:red'>解析上传表单出错</font>");
	 request.getRequestDispatcher("/WEB-INF/message.jsp").forward(request, response);
	
	 }
	 }
	
	}

	

	

	

	

	<%@ 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 'list.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>
	 <table border = "2" align = "center" width = "40%">
	 <tr>
	 <th>文件</th>
	 <th>操作</th>
	 </tr>
	 <c:forEach var = "entry" items = "${requestScope.MAP}">
	 <tr>
	 <td>${entry.value}</td>
	 <td>
	 <c:url var = "myURL" value = "/fileDownload">
	 <c:param name = "uuidFileName" value = "${entry.key}" />
	 </c:url>
	 <a style = "text-decoration:none"
	 href = "${myURL}">下载</a>
	 </td>
	 </tr>
	 </c:forEach>
	 </table>
	 </body>
	</html>
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