Spring MVC HiddenHttpMethodFilter 实现 REST风格的URL

同样接着上一篇的来，我们首先去web.xml中配置HiddenHttpMethodFilter

web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns="http://java.sun.com/xml/ns/javaee"
    xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"
    id="WebApp_ID" version="3.0">
    <display-name>springmvc1</display-name>
    <welcome-file-list>
        <welcome-file>index.jsp</welcome-file>
    </welcome-file-list>

    <!-- 配置org.springframework.web.filter.HiddenHttpMethodFilter：可以把POST请求转为DELETE或POST请求 -->
    <filter>
        <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>

    <!-- 配置  DispatcherServlet-->
    <servlet>
        <servlet-name>dispatcherServlet</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <!-- 配置DispatcherServlet的一个初始化参数：配置SprngMVC配置文件的位置和名称 -->
        <!--
            实际上也可以不通过contextConfigLocation来配置SpringMVC的配置文件，而使用
            默认的配置文件：/WEB-INF/<servlet-name>-servlet.xml
         -->
         <!--
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>classpath:springmvc.xml</param-value>
        </init-param>
         -->
        <load-on-startup>1</load-on-startup>
    </servlet>
    <servlet-mapping>
        <servlet-name>dispatcherServlet</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>
</web-app>

在index.jsp中加上以下的超链接测试用。

<form action="springmvc/testRest/1" method="post">
        <input type="hidden" name="_method" value="PUT">
        <input type="submit" value="TestRest PUT">
    </form>
    <br />
    <form action="springmvc/testRest/1" method="post">
        <input type="hidden" name="_method" value="DELETE">
        <input type="submit" value="TestRest DELETE">
    </form>
    <br />
    <form action="springmvc/testRest/1" method="post">
        <input type="submit" value="TestRest POST">
    </form>
    <br />
    <a href="springmvc/testRest/1">Test Rest Get</a>
    <br />

package com.hust.springmvc1;

import org.springframework.stereotype.Controller;
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.bind.annotation.SessionAttributes;

@SessionAttributes(value={"user"}, types={String.class})
@Controller
@RequestMapping("/springmvc")
public class SpringMVCTest { 

    private static final String SUCCESS = "success";

    /*
     * Rest 风格的 URL
     * 以 CRUD 为例：
     * 新增： /order POST
     * 修改： /order/1 PUT      update?id=1
     * 获取： /order/1 GET      get?id=1
     * 删除： /order/1 DELETE   delete?id=1
     *
     * 如何发送 PUT 请求和 DELETE 请求呢？
     * 1. 需要配置 HiddenHttpMethodFilter
     * 2. 需要发送POST请求
     * 3. 需要在发送POST请求时携带一个 name="_method" 的隐藏域， 值为 DELETE 或 PUT
     *
     * 在SpringMVC 的目标方法中如何得到 id 呢？
     * 使用 @PathVariable 注解
     */
    @RequestMapping(value = "/testRest/{id}", method = RequestMethod.PUT)
    public String testRestPut(@PathVariable Integer id) {
        System.out.println("testRest Put: " + id);
        return SUCCESS;
    }

    @RequestMapping(value = "/testRest/{id}", method = RequestMethod.DELETE)
    public String testRestDelete(@PathVariable Integer id) {
        System.out.println("testRest Delete: " + id);
        return SUCCESS;
    }

    @RequestMapping(value = "/testRest/{id}", method = RequestMethod.POST)
    public String testRest() {
        System.out.println("testRest POST ");
        return SUCCESS;
    }

    @RequestMapping(value = "/testRest/{id}", method = RequestMethod.GET)
    public String testRest(@PathVariable Integer id) {
        System.out.println("testRest GET: " + id);
        return SUCCESS;
    }
}

这样就能实现DELETE、PUT、POST、GET请求。

重复啰嗦一下。

如何发送 PUT 请求和 DELETE 请求呢？
* 1. 需要配置 HiddenHttpMethodFilter
* 2. 需要发送POST请求
* 3. 需要在发送POST请求时携带一个 name=”_method” 的隐藏域， 值为 DELETE 或 PUT