SpringMVC实现页面和java模型的数据交互以及文件上传下载和数据校验

<?xml version="1.0" encoding="UTF-8"?>
<beans
xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:tx="http://www.springframework.org/schema/tx"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:mvc="http://www.springframework.org/schema/mvc"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.0.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-4.0.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.0.xsd http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-4.0.xsd"> <!-- 启用注解 -->
<mvc:annotation-driven/>
<context:component-scan base-package="com.zhq.controller"/>
<!--配置静态资源访问  -->
<mvc:resources location="/images/" mapping="/images/**"/>
<mvc:resources location="/css/" mapping="/css/**"/>
<mvc:resources location="/js/" mapping="/js/**"/>
<!--视图分解器，把controller控制器返回的视图名称加上前缀及后缀，视图的路径最终得到/视图名.jsp  -->
<bean id="viewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver">
<property name="prefix" value="/"></property>
<property name="suffix" value=".jsp"></property>
</bean>
<!--校验器，配置validator  -->
<bean id="validator" class="org.springframework.validation.beanvalidation.LocalValidatorFactoryBean">
<property name="providerClass" value="org.hibernate.validator.HibernateValidator"/>
<property name="validationMessageSource" ref="reloadableResourceBundleMessageSource"/>
</bean>
<!-- 配置验证消息 -->
<bean id="reloadableResourceBundleMessageSource" class="org.springframework.context.support.ReloadableResourceBundleMessageSource"></bean>
<!--文件上传的参数配置  -->
<bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
<!--10485760字节，表示所有文件大小总和不超过10M  -->
<property name="maxUploadSize" value="10485760"/>
<!--设置上传文件时缓存区的大小  -->
<property name="maxInMemorySize" value="4096"/>
<!--设置字符编码  -->
<property name="defaultEncoding" value="UTF-8"/>
</bean>
<!--文件上传超过大小时的异常处理，页面跳转  -->
<bean id="exceptionResolver" class="org.springframework.web.servlet.handler.SimpleMappingExceptionResolver">
<property name="exceptionMappings">
<props>
<!--配置捕获异常类型  -->
<prop key="org.springframework.web.multipart.MaxUploadSizeExceededException">/errorFile</prop>
</props>
</property>
</bean>
</beans>

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://xmlns.jcp.org/xml/ns/javaee" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd" id="WebApp_ID" version="3.1">
<display-name>SpringMVC_01</display-name>
<welcome-file-list>
<welcome-file>index.html</welcome-file>
<welcome-file>index.htm</welcome-file>
<welcome-file>index.jsp</welcome-file>
<welcome-file>default.html</welcome-file>
<welcome-file>default.htm</welcome-file>
<welcome-file>default.jsp</welcome-file>
</welcome-file-list>
<!--配置springMVC的启动  -->
<servlet>
<!--可以约束springMVC的主配置文件如果在默认路径下时的文件名  -->
<servlet-name>springMVC</servlet-name>
<!--配置前端控制器  -->
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<!--当主配置文件不在默认路径下，则需要配置文件的路径  -->
<init-param>
<param-name>contextConfigLocation</param-name>
<param-value>classpath:config/springMVC-servlet.xml</param-value>
</init-param>
<!--配置springMVC 随程序启动而启动  -->
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>springMVC</servlet-name>
<!--/:表示拦截所有请求  -->
<url-pattern>/</url-pattern>
</servlet-mapping>
<!-- springMVC中文乱码过滤器 -->
<filter>
<filter-name>characterEncodingFilter</filter-name>
<filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
<!--初始化  encoding forceEncoding参数-->
<init-param>
<param-name>encoding</param-name>
<param-value>UTF-8</param-value>
</init-param>
<init-param>
<param-name>forceEncoding</param-name>
<param-value>true</param-value>
</init-param>
</filter>
<filter-mapping>
<filter-name>characterEncodingFilter</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
<error-page>
<error-code>404</error-code>
<location>/error.jsp</location>
</error-page>
</web-app>

package com.zhq.entity;

import java.util.List;

public class Grade {
private int gradeId;
private String gradeName;
private List<Student> students=null;

public Grade() {
super();
}

public Grade(int gradeId, String gradeName) {
super();
this.gradeId = gradeId;
this.gradeName = gradeName;
}

public int getGradeId() {
return gradeId;
}
public void setGradeId(int gradeId) {
this.gradeId = gradeId;
}
public String getGradeName() {
return gradeName;
}
public void setGradeName(String gradeName) {
this.gradeName = gradeName;
}

public List<Student> getStudents() {
return students;
}
public void setStudents(List<Student> students) {
this.students = students;
}
@Override
public String toString() {
return "Grade [gradeId=" + gradeId + ", gradeName=" + gradeName + "]";
}

}

package com.zhq.entity;

import java.text.SimpleDateFormat;
import java.util.Date;

import javax.validation.constraints.Size;

import org.hibernate.validator.constraints.Email;
import org.hibernate.validator.constraints.NotEmpty;
import org.hibernate.validator.constraints.Range;
import org.springframework.format.annotation.DateTimeFormat;

import jdk.nashorn.internal.objects.annotations.SpecializedFunction;

public class Student {
private int studentNo;
@Size(min=2,max=10,message="学生姓名为2-10")
private String name;
private String sex;
@Range(min=18,max=45,message="年龄18-45")
private int age;
@NotEmpty(message="手机不能为空")
private String phone;
@NotEmpty(message="地址不能为空")
private String address;
@DateTimeFormat(pattern="yyyy-MM-dd")
private Date birthday;
@Email(message="邮箱格式不正确")
private String email;
private Grade grade;

public Student() {
super();
}

public Student(int studentNo, String name, String sex, int age, String phone, String address
) {
super();
this.studentNo = studentNo;
this.name = name;
this.sex = sex;
this.age = age;
this.phone = phone;
this.address = address;
}

public int getStudentNo() {
return studentNo;
}
public void setStudentNo(int studentNo) {
this.studentNo = studentNo;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getSex() {
return sex;
}
public void setSex(String sex) {
this.sex = sex;
}
public Date getBirthday() {
return birthday;
}
public void setBirthday(Date birthday) {
this.birthday = birthday;
}
public String getPhone() {
return phone;
}
public void setPhone(String phone) {
this.phone = phone;
}
public String getAddress() {
return address;
}
public void setAddress(String address) {
this.address = address;
}
public String getEmail() {
return email;
}
public void setEmail(String email) {
this.email = email;
}
public Grade getGrade() {
return grade;
}
public void setGrade(Grade grade) {
this.grade = grade;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
@Override
public String toString() {
return "Student [studentNo=" + studentNo + ", name=" + name + ", sex=" + sex + ", age=" + age + ", phone="
+ phone + ", address=" + address + ", birthday=" +  sdf.format(birthday) + ", email=" + email
+ "]";
}

}

package com.zhq.entity;

public class Subject {
private int subjectNo;
private String subjectName;
private int classHour;
private Grade grade;
public int getSubjectNo() {
return subjectNo;
}
public void setSubjectNo(int subjectNo) {
this.subjectNo = subjectNo;
}
public String getSubjectName() {
return subjectName;
}
public void setSubjectName(String subjectName) {
this.subjectName = subjectName;
}
public int getClassHour() {
return classHour;
}
public void setClassHour(int classHour) {
this.classHour = classHour;
}
public Grade getGrade() {
return grade;
}
public void setGrade(Grade grade) {
this.grade = grade;
}
@Override
public String toString() {
return "Subject [subjectNo=" + subjectNo + ", subjectName=" + subjectName + ", classHour=" + classHour
+ "]";
}

}

package com.zhq.controller;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.UnsupportedEncodingException;
import java.net.URLEncoder;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.multipart.MultipartFile;
import org.springframework.web.multipart.MultipartHttpServletRequest;
import org.springframework.web.multipart.commons.CommonsMultipartResolver;

@Controller
@RequestMapping("/file")
public class FileController {
//文件上传
@RequestMapping("springUpload")
public String springUpload(HttpServletRequest request) {
//将当前上下文初始化给CommonsMultipartResolver(多部分解析器)
CommonsMultipartResolver multipartResolver=new CommonsMultipartResolver(request.getSession().getServletContext());
//检查form中是否有multipart/form-data
if(multipartResolver.isMultipart(request)) {
//将request变成多部分request
MultipartHttpServletRequest multiRequest=(MultipartHttpServletRequest) request;
//获取multiRequest中所有文件名
Iterator iter=multiRequest.getFileNames();
//遍历所有文件
while(iter.hasNext()) {
MultipartFile file=multiRequest.getFile(iter.next().toString());
if(file!=null&&file.getOriginalFilename()!="") {
String path=request.getSession().
getServletContext().getRealPath("/userfile")+"/"+
file.getOriginalFilename();
//上传
try {
file.transferTo(new File(path));
System.out.println(path);
request.setAttribute("msg", "上传成功！");
} catch (IllegalStateException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}else {
request.setAttribute("msg", "上传失败！");
}
return "uploadMsg
e498
";
}
//获取下载文件名列表
@RequestMapping("springFilelist")
public String springFilelist(HttpServletRequest request) {
//实现思路：先获取userfile目录下所有文件的文件名，保存，然后跳转到downloadFile.jsp展示
//创建集合Map<包含唯一标记的文件名,简短文件名>
Map<String,String> fileNames=new HashMap<String,String>();
//获取上传目录，以及其下所有的文件名
String basePath=request.getSession().getServletContext().getRealPath("/userfile")+"/";
//目录
File file=new File(basePath);
//目录下，所有文件名
String list[]=file.list();
//遍历，封装
if(list!=null&&list.length>0) {
for(int i=0;i<list.length;i++) {
//全名
String fileName=list[i];
//短名
String shortName=fileName.substring(fileName.lastIndexOf("\\")+1);
//封装
fileNames.put(fileName, shortName);
}
}
//保存到request域
try {
request.setCharacterEncoding("UTF-8");
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
}
request.setAttribute("fileNames", fileNames);
return "downloadFile";
}
//根据文件名下载文件
@RequestMapping("springDownload")
public void springDownload(HttpServletRequest request,HttpServletResponse response) {
//获取下载文件名称
String fileName=request.getParameter("fileName");
//GET方式获得的汉字需要转码,框架已经设置所以此处不用
/*fileName = new String(fileName.getBytes("ISO8859-1"),"UTF-8");*/
//先获取上传目录路径
String basePath=request.getSession().getServletContext().getRealPath("/userfile")+"/";
try {
//获取一个文件流
InputStream in = new FileInputStream(new File(basePath,fileName));
// 如果文件名是中文，需要进行url编码
fileName = URLEncoder.encode(fileName, "UTF-8");
// 设置下载的响应头
response.setHeader("content-disposition", "attachment;fileName=" + fileName);
//获取response字节流
OutputStream out = response.getOutputStream();
byte[] b = new byte[1024];
int len = -1;
while ((len = in.read(b)) != -1){
out.write(b, 0, len);
}
// 关闭
out.close();
in.close();
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}

}

package com.zhq.controller;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;

import com.zhq.entity.Grade;

@Controller
@RequestMapping("/grade")
public class GradeController {
//方式一传递数据到前端
@RequestMapping("/list/map")//默认返回grade/list/map.jsp
public Map<String,Grade> gradeList(){
Map<String,Grade> map=new HashMap<String, Grade>();
Grade grade=new Grade();
grade.setGradeName("一年级");
map.put("a", grade);
return map;
}
//方式二传递数据到前端
@RequestMapping("/list")
public String gradeList(Model model){
List<Grade> gradelist=new ArrayList<Grade>();
Grade grade=new Grade();
grade.setGradeName("二年级");
gradelist.add(grade);
model.addAttribute("gradelist", gradelist);
return "grade/gradelist";//返回视图grade/gradelist.jsp
}
}

package com.zhq.controller;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

/*import javax.servlet.http.HttpServletRequest;*/

import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.validation.BindingResult;
import org.springframework.validation.FieldError;
import org.springframework.validation.annotation.Validated;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.servlet.ModelAndView;

import com.zhq.entity.Grade;
import com.zhq.entity.Student;

@Controller
@RequestMapping(value= {"/student","/stu"})
public class StudentController {
@RequestMapping("/list")
public ModelAndView list() {
List<Student> list=new ArrayList<Student>();
list.add(new Student(1000, "张三", "男", 20, "13125283736", "广东广州"));
list.add(new Student(1001, "李四", "男", 21, "13838384388", "广东珠海"));
list.add(new Student(1002, "王婷", "女", 22, "15238384499", "广东中山"));
return new ModelAndView("studentList","data",list);
}
//method=RequestMethod.GET表示只接收GET请求，一般要初始化数据时调用
@RequestMapping(value={"/add","/add1"},method=RequestMethod.GET)
public ModelAndView add() {
List<Grade> list=new ArrayList<Grade>();//初始化年级下拉框数据
list.add(new Grade(1, "一年级"));
list.add(new Grade(2, "二年级"));
list.add(new Grade(3, "三年级"));
return new ModelAndView("studentAdd","glist",list);
}
//method=RequestMethod.POST表示只接收POST请求
//@Validated作用就是将pojo内的注解数据校验规则生效，BindingResult用于获取校验失败信息
@RequestMapping(value={"/add","/add2"},method=RequestMethod.POST)
public ModelAndView add(@Validated Student student,BindingResult result,Model model) {
//传参取值有三种方式(前两种标签名和参数名要相同):
//1.ModelAndView add(Student student)自动封装成对象
//2.ModelAndView add(String name, int gradeId)自动匹配参数
//3.ModelAndView add(HttpServletRequest request)获取请求
if(result.hasErrors()) {
model.addAttribute("msg", "验证信息错误！");
Map<String,String> errors=new HashMap<String,String>();
for(FieldError err:result.getFieldErrors()) {//遍历错误提示将错误信息存入Map
errors.put(err.getField(), err.getDefaultMessage());
}
model.addAttribute("errors", errors);
List<Grade> list=new ArrayList<Grade>();//年级下拉框信息
list.add(new Grade(1, "一年级"));
list.add(new Grade(2, "二年级"));
list.add(new Grade(3, "三年级"));
model.addAttribute("glist", list);
return new ModelAndView("studentAdd");
/*return new ModelAndView("forward:/student/add1");*/
}else {
//转发到/student/list方法或者使用redirect:/student/list
return new ModelAndView("redirect:/student/list");
}

}
//占位符方式传递参数/del/100
@RequestMapping("/del/{id:\\d+}")//\\d+表示只匹配数字
public ModelAndView delete(@PathVariable(value="id") Integer id) {
System.out.println(id);
return new ModelAndView("redirect:/student/list","id",id);
}
//默认传递参数方式/find?id=100
@RequestMapping("/find")
public ModelAndView findStudentByid(Integer id) {
System.out.println(id);
return new ModelAndView("studentAdd","id",id);
}
}

<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
<link rel="stylesheet" href="css/index.css" />
</head>
<body>
<img src="images/ws.gif"><br>
<a href="${pageContext.request.contextPath}/student/list">学生信息列表</a><br>
<a href="${pageContext.request.contextPath}/student/add">添加学生</a><br>
<a href="${pageContext.request.contextPath}/grade/list/map">年级列表1</a><br>
<a href="${pageContext.request.contextPath}/grade/list">年级列表2</a><br>
<a href="${pageContext.request.contextPath}/uploadFile.jsp">多文件上传</a><br>
<a href="${pageContext.request.contextPath}/file/springFilelist">文件下载</a><br>
</body>
</html>

<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
<style type="text/css">
table {border-collapse:collapse;}
table,th,td {border: 1px solid black;}
</style>
</head>
<body>
欢迎！
<table>
<tr>
<th>姓名</th>
<th>性别</th>
<th>年龄</th>
<th>电话</th>
<th>地址</th>
<th>操作</th>
</tr>
<c:forEach items="${data}" var="student" >
<tr>
<td>${student.name}</td>
<td>${student.sex}</td>
<td>${student.age}</td>
<td>${student.phone}</td>
<td>${student.address}</td>
<td><a href="${pageContext.request.contextPath}/student/del/${student.studentNo}" onclick="return confirm('你确定要删除吗？')">删除</a></td>
</tr>
</c:forEach>
</table>
</body>
</html>

<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
添加页面！
<form action="${pageContext.request.contextPath}/student/add" method="post">
<p>姓名：<input name="name">${errors.name}<br></p>
<p>年龄：<input name="age">${errors.age}<br></p>
<p>性别：
<select name="sex">
<option value="男">男</option>
<option value="女">女</option>
</select>
</p>
<p>地址：<input name="address">${errors.address}<br></p>
<p>班级：

<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
添加页面！
<form action="${pageContext.request.contextPath}/student/add" method="post">
<p>姓名：<input name="name">${errors.name}<br></p>
<p>年龄：<input name="age">${errors.age}<br></p>
<p>性别：
<select name="sex">
<option value="男">男</option>
<option value="女">女</option>
</select>
</p>
<p>地址：<input name="address">${errors.address}<br></p>
<p>班级：
<select name="grade.gradeId">
<c:forEach items="${glist}" var="grade">
<option value="${grade.gradeId}">${grade.gradeName}</option>
</c:forEach>
</select><br>
</p>
<p><input type="submit" value="保存">${msg}<br></p>
</form>
</body>
</html>

<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
<c:forEach items="${map}" var="entry">
${entry.key}:${entry.value.gradeName}<br>
</c:forEach>

${a.gradeName}<br>

</body>
</html>

<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
<c:forEach items="${gradelist}" var="grade">
${grade.gradeName}<br>
</c:forEach>
</body>
</html>

<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
<h2>多文件上传</h2>
<form action="${pageContext.request.contextPath}/file/springUpload" name="uploadFile" enctype="multipart/form-data" method="post">
<p><input type="file" name="file1"></p>
<p><input type="file" name="file2"></p>
<p><input type="file" name="file3"></p>
<input type="submit" value="上传">
</form>
</body>
</html>

<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
${msg}
</body>
</html>

<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
文件超出大小10M!上传失败！
<a href="${pageContext.request.contextPath}/uploadFile.jsp">返回</a>
</body>
</html>

<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>下载页面</title>
<style type="text/css">
table {border-collapse:collapse;}
table,th,td {border: 1px solid black;}
</style>
</head>
<body>
<h3 align="center">下载列表</h3>
<table align="center">
<tr>
<th>序号</th>
<th>文件名</th>
<th>操作</th>
</tr>
<c:forEach var="en" items="${requestScope.fileNames}" varStatus="vs">
<tr>
<td>${vs.count }</td>
<td>${en.value }</td>
<td>
<%--<a href="${pageContext.request.contextPath }/springDownload?method=down&..">下载</a>--%>
<!-- 构建一个地址  -->
<c:url var="url" value="springDownload">
<c:param name="method" value="down"></c:param>
<c:param name="fileName" value="${en.key}"></c:param>
</c:url>
<!-- 使用上面地址 -->
<a href="${url}">下载</a>
</td>
</tr>
</c:forEach>
</table>
</body>
</html>

<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
错误页面！404
</body>
</html>