form表单上传文件 ???<form method="post" enctype="multipart/form-data" action="saveUser.do"> ???????用户名<input type="text" name="username"><br/> ???????头像<input type="file" name="myPic"><br/> ???????<input type="submit" > ???</form>

package com.qy.entity;public class User { ???private String username; ???private String myPic; ???public String getUsername() { ???????return username; ???} ???public void setUsername(String username) { ???????this.username = username; ???} ???public String getMyPic() { ???????return myPic; ???} ???public void setMyPic(String myPic) { ???????this.myPic = myPic; ???} ???????}

package com.qy.servlet;import java.io.IOException;import java.util.Arrays;import javax.servlet.ServletException;import javax.servlet.annotation.MultipartConfig;import javax.servlet.annotation.WebServlet;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import javax.servlet.http.Part;import com.qy.entity.User;@WebServlet("/saveUser.do")@MultipartConfigpublic class UserSaveServlet extends HttpServlet{ ???????@Override ???protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { ???????String username = request.getParameter("username"); ???????Part part = request.getPart("myPic"); ???????System.out.println(part); ???????//验证文件大小，后缀是否满足要求，获取原始文件名 ???????long size = part.getSize(); ???????//1m ?1024*1024 ???????if(size > 1024*1024){ ???????????System.out.println("文件大于1M！"); ???????????return ; ???????} ???????// ???????String file = part.getHeader("Content-Disposition");//form-data; name="myPic"; filename="1024.jpg" ???????//获取后缀 ?截取 ?. ?????????String suffix = file.substring(file.lastIndexOf(".")+1, file.length()-1); ???????//比对后缀格式是否正确 ???????String[] suffixs = {"jpg","png","gif"};content.lastIndexOf("=\"")+2,content.lastIndexOf("\"") ???????boolean flag = Arrays.asList(suffixs).contains(suffix); ???????if(!flag){ ???????????System.out.println("文件格式不正确！"); ???????????return ; ???????} ???????//获取保存路径 ???????String path = request.getServletContext().getRealPath("/images/"); ???????????????//保存文件到磁盘 ???????String filename = System.currentTimeMillis()+"."+suffix; ???????part.write(path+filename); ???????????????????????//保存用户数据到数据库 ???????User user = new User(); ???????user.setUsername(username); ???????user.setMyPic("images/"+filename); ???????????????//调用dao层方法保存对象 ???????????????//控制页面跳转 ???}}

 ????ajax上传文件 ?<br/> ???<form id="uploadFile"> ???????<input type="file" name="myPic" id="myPic"> ????????<input type="button" value="上传" id="uploadPic"> ???</form>

package com.qy.servlet;import java.io.IOException;import java.util.Arrays;import javax.servlet.ServletException;import javax.servlet.annotation.MultipartConfig;import javax.servlet.annotation.WebServlet;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import javax.servlet.http.Part;import com.qy.entity.User;@WebServlet("/saveUser2.do")@MultipartConfigpublic class UserSaveServlet2 extends HttpServlet{ ???????@Override ???protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { ???????response.setContentType("text/html;charset=utf-8"); ???????????????String username = request.getParameter("username"); ???????Part part = request.getPart("myPic"); ???????//验证文件大小，后缀是否满足要求，获取原始文件名 ???????long size = part.getSize(); ???????//1m ?1024*1024 ???????if(size > 1024*1024){ ???????????System.out.println("文件大于1M！"); ???????????response.getWriter().append("文件大于1M！"); ???????????return ; ???????} ???????// ???????String file = part.getHeader("Content-Disposition");//form-data; name="myPic"; filename="1024.jpg" ???????//获取后缀 ?截取 ?. ?????????String suffix = file.substring(file.lastIndexOf(".")+1, file.length()-1); ???????//比对后缀格式是否正确 ???????String[] suffixs = {"jpg","png","gif"}; ???????boolean flag = Arrays.asList(suffixs).contains(suffix); ???????if(!flag){ ???????????System.out.println("文件格式不正确！"); ???????????response.getWriter().append("文件格式不正确!"); ???????????return ; ???????} ???????//获取保存路径 ???????String path = request.getServletContext().getRealPath("/images/"); ???????????????//保存文件到磁盘 ???????String filename = System.currentTimeMillis()+"."+suffix; ???????part.write(path+filename); ???????????????????????//保存用户数据到数据库 ???????User user = new User(); ???????user.setUsername(username); ???????user.setMyPic("images/"+filename); ???????????????//调用dao层方法保存对象 ???????????????//返回保存成功 ???????response.getWriter().append("上传成功！"); ???}}