Spring MVC 框架：第七章：REST 架构风格 (1)

2021 年 11 月 11 日
本文字数：6591 字
阅读完需：约 22 分钟

http://localhost:8080/shop/product/cellPhone/iPhone

第二节 SpringMVC 对四种请求方式的支持

1.说明

受 HTML 的限制，只有 GET 请求和 POST 请求是可以直接生成的。为了生成 PUT 和 DELETE 请求方式我们需要借助一个过滤器：org.springframework.web.filter.HiddenHttpMethodFilter，这个过滤器可以将 POST 请求转换为 PUT 或 DELETE 等其他形式。

2.HiddenHttpMethodFilter 的使用方法

①在 web.xml 中进行配置，拦截所有资源。

<filter-name>HiddenHttpMethodFilter</filter-name>

<filter-class>org.springframework.web.filter.HiddenHttpMethodFilter</filter-class>

</filter>

<filter-mapping>

<filter-name>HiddenHttpMethodFilter</filter-name>

<url-pattern>/*</url-pattern>

</filter-mapping>

②在表单隐藏域中通过_method 请求参数附带请求方式名称

jsp 代码：

③通过点击超链接执行删除操作。

这是一个难点，超链接中没有表单隐藏域，所以需要将超链接转换为表单进行提交，这就需要借助于 JavaScript。

[1]在页面上创建一个 action 属性为空的 form 表单

jsp 代码：

</form>

[2]给所有超链接绑定单击响应函数

jsp 代码：

jsp 中 jquery 代码：

$(".empRemove").click(function(){

//※※※※※※※※※以下操作将 GET 请求转换为 POST 请求※※※※※※※※※

//1.先获取到当前超链接原本要访问的 URL 地址

//this 是当前被点击的超链接的引用，是 DOM 对象

var targetUrl = this.href;

//2.获取负责转换请求方式的表单的 jQuery 对象

var $f o r m =$ ("form");

//3.将表单的 action 属性设置为超链接的 URL 地址

$form.attr("action",targetUrl );

//4.提交表单

//将表单元素封装为 jQuery 对象后调用 submit()方法可以提交表单，相当于点击表单的提交按钮

$form.submit();

//5.超链接不跳转

return false;

});

@PathVariable 注解

通过 URL 地址携带的数据需要通过 @PathVariable 注解来获取。它的用法是：

Handled 代码：

//使用 @PathVariable 注解将 URL 地址中的变量匹配出来

@RequestMapping(value="/emp/{empId}", method=RequestMethod.DELETE)

public String testPathVariable(@PathVariable("empId") String empId) {

System.out.println("empId="+empId);

return "redirect:/result";

}

实战代码：

项目结构

web.xml

<servlet-name>springDispatcherServlet</servlet-name>

<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>

<init-param>

<param-name>contextConfigLocation</param-name>

<param-value>classpath:spring-mvc.xml</param-value>

</init-param>

<load-on-startup>1</load-on-startup>

</servlet>

<servlet-mapping>

<servlet-name>springDispatcherServlet</servlet-name>

<url-pattern>/</url-pattern>

</servlet-mapping>

<filter-name>CharacterEncodingFilter</filter-name>

<filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>

<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>

<filter-name>HiddenHttpMethodFilter</filter-name>

<filter-class>org.springframework.web.filter.HiddenHttpMethodFilter</filter-class>

</filter>

<filter-mapping>

<filter-name>HiddenHttpMethodFilter</filter-name>

<url-pattern>/*</url-pattern>

</filter-mapping>

spring-mvc.xml

<?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:context="http://www.springframework.org/schema/context"

xmlns:mvc="http://www.springframework.org/schema/mvc"

xsi:schemaLocation="http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-4.0.xsd

http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd

http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.0.xsd">

<context:component-scan base-package="com.*" />

<bean id="viewResolver"

class="org.springframework.web.servlet.view.InternalResourceViewResolver">

</bean>

mvc:annotation-driven</mvc:annotation-driven>

<mvc:default-servlet-handler />

</beans>

index.jsp

<%@ 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>

<title>Insert title here</title>

</head>

<body>

</body>

</html>

dataList.jsp

<%@ 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>

<title>Insert title here</title>

$(function(){

$(".remove").click(function(){

var data = $(this).parents("tr").children("td:eq(1)").text();

var confirm = window.confirm("你确定要"+data+"删除吗？");

if(!confirm){

return false;

}

//※※※※※※※※※以下操作将 GET 请求转换为 POST 请求※※※※※※※※※

//1.先获取到当前超链接原本要访问的 URL 地址

//this 是当前被点击的超链接的引用，是 DOM 对象

var targetUrl = this.href;

//2.获取负责转换请求方式的表单的 jQuery 对象

var $f o r m =$ ("form");

//3.将表单的 action 属性设置为超链接的 URL 地址

$form.attr("action",targetUrl );

//4.提交表单

//将表单元素封装为 jQuery 对象后调用 submit()方法可以提交表单，相当于点击表单的提交按钮

$form.submit();

//5.超链接不跳转

return false;

});

</script>

</head>

<body>

</form>

<table>

<c:if test="${empty requestScope.list }">

<tr>

<td>没有查询到数据</td>

</tr>

</c:if>

<c:if test="${!empty requestScope.list }">

<tr>

</tr>

<c:forEach items="${requestScope.list }" var="list">

<tr>

<td>${list.empId}</td>

<td>${list.empName}</td>

<td>${list.department.deptName }</td>

</tr>

</c:forEach>

</c:if>

<tr>

</tr>

</table>

</center>

</body>

</html>

dataEdit.jsp

<%@ 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>

<title>Insert title here</title>

</head>

<body>

<form action="${pageContext.request.contextPath }/emp"

method="post">

<table>

<tr>

</td>

</tr>

<tr>

</tr>

<tr>

<c:if test="${!empty deptList }">

<c:forEach items="${requestScope.deptList}" var="dept">

<c:if test="${dept.deptId==requestScope.emdit.department.deptId }">

<option value=" $d e p t . d e p t I d " s e l e c t e d = " s e l e c t e d " >$ {dept.deptName }</option>

</c:if>

<option value=" $d e p t . d e p t I d " s e l e c t e d = " s e l e c t e d " >$ {dept.deptName }</option>

</c:forEach>

</c:if>

</select></td>

</tr>

<tr>

</tr>

</table>

</form>

</body>

</html>

dataAdd.jsp

<%@ 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>

<title>Insert title here</title>

</head>

<body>

<table>

<tr>

<td>

</td>

</tr>

<tr>

<td>

</td>

</tr>

<tr>

<td>

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复制代码

所在部门</td>

<td>

<c:if test="${empty deptList }">

<option>部门数据查询失败！！！</option>

</c:if>

<c:if test="${!empty deptList }">

<c:forEach items="${requestScope.deptList}" var="dept">

<option value=" $d e p t . d e p t I d " >$ {dept.deptName }</option>

</c:forEach>

</c:if>

</select>

</td>

</tr>

<tr>

</td>

</tr>

</table>

</form>

</body>

</html>

DeptDao.java

package com.dao;

import java.util.ArrayList;

import java.util.HashMap;

import java.util.List;

import java.util.Map;

import java.util.UUID;

import org.springframework.stereotype.Repository;

import com.pojo.Department;

@Repository

public class DeptDao {

private static Map<String, Department> dataMap;

private static Map<String, Department> namedMap;

static {

dataMap = new HashMap<>();

namedMap = new HashMap<>();

Department department = new Department(UUID.randomUUID().toString(), "市场部");

dataMap.put(department.getDeptId(), department);

namedMap.put(department.getDeptName(), department);

department = new Department(UUID.randomUUID().toString(), "销售部");

dataMap.put(department.getDeptId(), department);

namedMap.put(department.getDeptName(), department);

department = new Department(UUID.randomUUID().toString(), "行政部");

dataMap.put(department.getDeptId(), department);

namedMap.put(department.getDeptName(), department);

department = new Department(UUID.randomUUID().toString(), "人事部");

dataMap.put(department.getDeptId(), department);

namedMap.put(department.getDeptName(), department);

department = new Department(UUID.randomUUID().toString(), "技术部");

dataMap.put(department.getDeptId(), department);

namedMap.put(department.getDeptName(), department);

department = new Department(UUID.randomUUID().toString(), "公关部");

dataMap.put(department.getDeptId(), department);

namedMap.put(department.getDeptName(), department);

}

public static Department getDeptByName(String deptName) {

return namedMap.get(deptName);

}

public static Department getDeptById(String uuid) {

return dataMap.get(uuid);

}

public List<Department> getDeptList() {

return new ArrayList<>(dataMap.values());

}

EmpDao.java

package com.dao;

import java.util.ArrayList;

import java.util.HashMap;

import java.util.List;

import java.util.Map;

import java.util.UUID;

import org.springframework.stereotype.Repository;

import com.pojo.Department;

import com.pojo.Employee;

@Repository

public class EmpDao {

private static Map<String, Employee> dataMap;

static {

dataMap = new HashMap<>();

String empId = UUID.randomUUID().toString();

dataMap.put(empId, new Employee(empId, "乔峰", "SSN001", DeptDao.getDeptByName("市场部")));