文章目录

• 六、SpringMVC的Restful支持
• • 6.1 RESTFUL示例：
  • 6.2 基于restful风格的url
  • 6.3 基于Rest风格的方法
  • 6.4 配置HiddenHttpMethodFilter
  • 6.5 Restful相关注解

六、SpringMVC的Restful支持

REST（英文：Representational State Transfer，即表述性状态传递，简称REST）RESTful是一种软件架构风格、设计风格，而不是标准，只是提供了一组设计原则和约束条件。它主要用于客户端和服务器交互类的软件。基于这个风格设计的软件可以更简洁，更有层次，更易于实现缓存等机制。

6.1 RESTFUL示例：

请求方式共有其中，其中对应的就是HttpServlet中的七个方法：

Tips：目前我们的jsp、html，都只支持get、post。

6.2 基于restful风格的url

• 添加

URL：

http://localhost:8080/user

请求体：

{"username":"zhangsan","age":20}

提交方式： post

• 修改

http://localhost:8080/user/1

• 请求体：

{"username":"lisi","age":30}

提交方式：put

• 删除

http://localhost:8080/user/1

提交方式：delete

• 查询

http://localhost:8080/user/1

提交方式：get

6.3 基于Rest风格的方法

• 引入依赖：

org.springframeworkspring-webmvc5.2.9.RELEASEorg.apache.tomcattomcat-api8.5.71org.projectlomboklombok1.18.18

• 实体类：

package com.dfbz.entity;import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;/*** @author lscl* @version 1.0* @intro:*/
@Data
@AllArgsConstructor
@NoArgsConstructor
public class City {private Integer id;         // 城市idprivate String cityName;    // 城市名称private Double GDP;         // 城市GDP,单位亿元private Boolean capital;    // 是否省会城市
}

• 测试代码：

package com.dfbz.controller;import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.*;import javax.servlet.http.HttpServletResponse;
import java.io.IOException;/*** @author lscl* @version 1.0* @intro:*/
@Controller
@RequestMapping("/city")
public class CityController {/*** 新增*/@PostMappingpublic void save(HttpServletResponse response) throws IOException {response.getWriter().write("save...");}/*** 删除** @param id* @param response* @throws IOException*/@DeleteMapping("/{id}")public void delete(@PathVariable Integer id, HttpServletResponse response) throws IOException {response.getWriter().write("delete...id: " + id);}/*** 修改** @param id* @param response* @throws IOException*/@PutMapping("/{id}")public void update(@PathVariable Integer id, HttpServletResponse response) throws IOException {response.getWriter().write("update...id: " + id);}/*** 根据id查询** @param id* @param response* @throws IOException*/@GetMapping("/{id}")public void findById(@PathVariable Integer id, HttpServletResponse response) throws IOException {response.getWriter().write("findById...id: " + id);}
}

注意：restful风格的请求显然与我们之前的.form后置的请求相悖，我们把拦截规则更换为：/

• 准备一个表单：
• Demo01.jsp：

<%@ page contentType="text/html;charset=UTF-8" language="java" %>



新增

删除
<%--建立一个名为_method的一个表单项--%>
修改

查询

6.4 配置HiddenHttpMethodFilter

默认情况下，HTML页面中的表单并不支持提交除GET/POST之外的请求，但SpringMVC提供有对应的过滤器来帮我们解决这个问题；

在web.xml中添加配置：

methodFilterorg.springframework.web.filter.HiddenHttpMethodFilter

methodFilter/*

相关源码：

public class HiddenHttpMethodFilter extends OncePerRequestFilter {private static final List ALLOWED_METHODS;public static final String DEFAULT_METHOD_PARAM = "_method";private String methodParam = "_method";public HiddenHttpMethodFilter() {}public void setMethodParam(String methodParam) {Assert.hasText(methodParam, "'methodParam' must not be empty");this.methodParam = methodParam;}protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response, FilterChain filterChain) throws ServletException, IOException {HttpServletRequest requestToUse = request;if ("POST".equals(request.getMethod()) && request.getAttribute("javax.servlet.error.exception") == null) {// 获取request中_method表单项的值String paramValue = request.getParameter(this.methodParam);if (StringUtils.hasLength(paramValue)) {// 全部转换为大写(delete--->DELETE)String method = paramValue.toUpperCase(Locale.ENGLISH);if (ALLOWED_METHODS.contains(method)) {requestToUse = new HiddenHttpMethodFilter.HttpMethodRequestWrapper(request, method);}}}filterChain.doFilter((ServletRequest)requestToUse, response);}static {ALLOWED_METHODS = Collections.unmodifiableList(Arrays.asList(HttpMethod.PUT.name(), HttpMethod.DELETE.name(), HttpMethod.PATCH.name()));}private static class HttpMethodRequestWrapper extends HttpServletRequestWrapper {private final String method;public HttpMethodRequestWrapper(HttpServletRequest request, String method) {// 修改request自身的的method值super(request);this.method = method;}public String getMethod() {return this.method;}}
}

6.5 Restful相关注解

• @GetMapping：接收get请求
• @PostMapping：接收post请求
• @DeleteMapping：接收delete请求
• @PutMapping：接收put请求

修改后的CityController：

package com.dfbz.controller;import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.*;import javax.servlet.http.HttpServletResponse;
import java.io.IOException;@Controller
@RequestMapping("/city")
public class CityController_RestFul {/*** 新增*/@PostMappingpublic void save(HttpServletResponse response) throws IOException {response.getWriter().write("save...");}/*** 删除** @param id* @param response* @throws IOException*/@DeleteMapping("/{id}")public void delete(@PathVariable Integer id, HttpServletResponse response) throws IOException {response.getWriter().write("delete...id: " + id);}/*** 修改* @param id* @param response* @throws IOException*/@PutMapping("/{id}")public void update(@PathVariable Integer id, HttpServletResponse response) throws IOException {response.getWriter().write("update...id: " + id);}/*** 根据id查询** @param id* @param response* @throws IOException*/@GetMapping("/{id}")public void findById(@PathVariable Integer id, HttpServletResponse response) throws IOException {response.getWriter().write("findById...id: " + id);}
}