0.项目结构
1.在WebRoot下创建index.jsp页面
1 <%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%> 2 <% 3 String path = request.getContextPath(); 4 String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/"; 5 %> 6 7 <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> 8 <html> 9 <head> 10 <base href="<%=basePath%>"> 11 12 <title>My JSP 'index.jsp' starting page</title> 13 <meta http-equiv="pragma" content="no-cache"> 14 <meta http-equiv="cache-control" content="no-cache"> 15 <meta http-equiv="expires" content="0"> 16 <meta http-equiv="keywords" content="keyword1,keyword2,keyword3"> 17 <meta http-equiv="description" content="This is my page"> 18 <!-- 19 <link rel="stylesheet" type="text/css" href="styles.css"> 20 --> 21 </head> 22 23 <body> 24 <form action="UploadServlet" enctype="multipart/form-data" method="post"> 25 <p>姓名：<input type="text" name="user"/></p> 26 <p>选择图片：<input type="file" name="nfile"/></p> 27 <p><input type="submit" value="提交"/></p> 28 </form> 29 </body> 30 </html>
2.在src下的com.servlet包下创建UploadServlet.java文件
1 package com.servlet; 2 3 import java.io.File; 4 import java.io.IOException; 5 import java.io.PrintWriter; 6 import java.util.Arrays; 7 import java.util.List; 8 9 import javax.servlet.ServletException; 10 import javax.servlet.http.HttpServlet; 11 import javax.servlet.http.HttpServletRequest; 12 import javax.servlet.http.HttpServletResponse; 13 14 import org.apache.commons.fileupload.FileItem; 15 import org.apache.commons.fileupload.FileUploadBase; 16 import org.apache.commons.fileupload.FileUploadException; 17 import org.apache.commons.fileupload.disk.DiskFileItemFactory; 18 import org.apache.commons.fileupload.servlet.ServletFileUpload; 19 20 public class UploadServlet extends HttpServlet { 21 public void doGet(HttpServletRequest request, HttpServletResponse response) 22 throws ServletException, IOException { 23 this.doPost(request, response); 24 } 25 26 public void doPost(HttpServletRequest request, HttpServletResponse response) 27 throws ServletException, IOException { 28 //1.乱码处理 29 request.setCharacterEncoding("UTF-8"); 30 response.setCharacterEncoding("UTF-8"); 31 response.setContentType("text/html;charset=UTF-8"); 32 //创建输出流对象（负责在前台页面（写入）打印内容的） 33 PrintWriter out=response.getWriter(); 34 35 //2.得知请求中的数据是否包含二进制数据 36 boolean isMultipart=ServletFileUpload.isMultipartContent(request); 37 38 //3.如果包含 39 if(isMultipart){ 40 //3.1 创建封装表单数据的对象 41 DiskFileItemFactory factory=new DiskFileItemFactory(); 42 43 //3.2 设置文件缓冲区大小4KB 44 factory.setSizeThreshold(4096); 45 46 //3.3 创建上传表单数据的对象 47 ServletFileUpload upload=new ServletFileUpload(factory); 48 49 //3.4 设置上传单个文件的最大限制 50 upload.setSizeMax(1024*30); 51 52 try { 53 //3.5 解析请求中上传的表单数据，并将解析的内容的放入list集合 54 List<FileItem> filelist=upload.parseRequest(request); 55 56 //3.6 循环存放表单数据的集合把普通字段和二进制字段取出来 57 for (FileItem f : filelist) { 58 //3.6.1 如果是普通字段 59 if(f.isFormField()){ 60 //(1)获取普通字段的name属性值：user 61 String normalFiled=f.getFieldName(); 62 63 //(2)判断如果name属性值是想要的就取对应值 64 if(normalFiled.equals("user")){ 65 //输出name属性所对应的value值 66 out.print(f.getString("UTF-8")+"上传了文件！<br/>"); 67 } 68 69 }else{ 70 //3.6.2 如果是二进制文件字段 71 //(1)获取上传的文件名 72 String uploadFileName=f.getName(); 73 74 //(2)通过Arrays的aslist方法创建固定的集合，规定的文件格式 75 List<String> fileType=Arrays.asList("gif","bmp","jpg","png"); 76 77 //(3)返回文件的后缀 78 String ext=uploadFileName.substring(uploadFileName.lastIndexOf(".")+1); 79 80 //(4)判断文件类型是否允许在制定范围 81 if(fileType.contains(ext)){ 82 //(4.1)判断如果文件名不为空，将数值取出 83 if(uploadFileName!=null && !uploadFileName.equals("")){ 84 //(4.1.1)获取上传的文件路径 85 String uploadFilePath= 86 request.getSession().getServletContext().getRealPath("upload/"); 87 88 //拼接路径：第一个参数是文件夹，第二个参数是文件名 89 File saveFile=new File(uploadFilePath,f.getName()); 90 91 //(4.1.2)上传到服务器 92 f.write(saveFile); 93 94 out.print("上传成功后的文件名是："+uploadFileName+",文件大小是："+f.getSize()+"bytes!<br/>"); 95 out.print("上传的文件夹路径："+uploadFilePath+"<br/>"); 96 out.print("上传的文件全路径："+saveFile.getAbsolutePath()+"<br/>"); 97 98 }else{ 99 out.print("二进制文件名为空！"); 100 } 101 }else{ 102 out.print("文件上传失败！，文件类型只能是gif.bmp,jpg,png"); 103 } 104 } 105 } 106 107 } catch (FileUploadBase.SizeLimitExceededException e) { 108 out.print("文件上传失败，文件太大，单个文件的最大限制是："+upload.getSizeMax()+"bytes!!") ; 109 e.printStackTrace(); 110 } catch (FileUploadException e) { 111 // TODO Auto-generated catch block 112 e.printStackTrace(); 113 } catch (Exception e) { 114 // TODO Auto-generated catch block 115 e.printStackTrace(); 116 } 117 118 }else{ 119 //4.不包含 120 out.print("表单中不包含二进制数据！"); 121 } 122 123 } 124 125 }