Spring Boot 学习（一）@RequestAttribute @MatrixVariable @UrlPathHelper

@GetMapping("/send")
    public String getmessage(HttpServletRequest request) {
        request.setAttribute("msg","跳转");     //设置参数
        request.setAttribute("code",123);

        return "forward:/success";  //转发到success请求
    }

　　 @ResponseBody    //注意要加上这个注解，否则会出现500报错
    @GetMapping("/success")
    public Map success(@RequestAttribute("msg") String msg,     //通过RequestAttribute获取请求域中的所有值
                       @RequestAttribute("code") Integer code,
                        HttpServletRequest request) {    //获取到send的数据msg
        Object msg1 = request.getAttribute("msg");
        Map<String,Object> map = new HashMap<>();
        map.put("reqMethod_msg",msg1);  //获取原生servlet中的request的值
        map.put("annotation_msg",msg);  //获取基于注解额request的值
        return map;
    }

package com.sp.Controller;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestAttribute;
import org.springframework.web.bind.annotation.ResponseBody;
import javax.servlet.http.HttpServletRequest;
import java.util.HashMap;
import java.util.Map;

@Controller   //这里只声明了Controller注解
public class RequestController {

    @GetMapping("/send")
    public String getmessage(HttpServletRequest request) {
        request.setAttribute("msg","跳转");
        request.setAttribute("code",123);

        return "forward:/success";  //转发到success请求
    }
    @ResponseBody     //因此在显示页面数据需要加上注解ResponseBody
    @GetMapping("/success")
    public Map success(@RequestAttribute("msg") String msg,     //通过RequestAttribute获取请求域中的所有值
                       @RequestAttribute("code") Integer code,
                        HttpServletRequest request) {    //获取到send的数据msg
        Object msg1 = request.getAttribute("msg");
        Map<String,Object> map = new HashMap<>();
        map.put("reqMethod_msg",msg1);  //获取原生servlet中的request的值
        map.put("annotation_msg",msg);  //获取基于注解额request的值
        return map;
    }
}

package com.sp.config;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.PathMatchConfigurer;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
import org.springframework.web.util.UrlPathHelper;

@Configuration(proxyBeanMethods = false)
public class WebConfig /*implements WebMvcConfigurer */{
//      写法一
//    @Override
//    public void configurePathMatch(PathMatchConfigurer configurer) {  //对configurePathMatch进行重写
//        UrlPathHelper urlPathHelper = new UrlPathHelper();
//        urlPathHelper.setRemoveSemicolonContent(false);  //将RemoveSemicolonContent设置为false,此时矩阵变量才能生效
//        configurer.setUrlPathHelper(urlPathHelper);
//    }
//    写法二
      @Bean   //自己定义一个组件
    public WebMvcConfigurer webMvcConfigurer() {
          return new WebMvcConfigurer() {
              public void configurePathMatch(PathMatchConfigurer configurer) {
                  UrlPathHelper urlPathHelper = new UrlPathHelper();
                  urlPathHelper.setRemoveSemicolonContent(false);
                configurer.setUrlPathHelper(urlPathHelper);
              }
          };
      }

}

在UrlPathHelper中默认情况下是移除分号内容

@GetMapping("/cars/{path}")           //矩阵变量必须有url路径变量才能被解析,否则404

public Map carsell(@MatrixVariable("low") Integer low, //不是请求参数，而是矩阵变量，需要加上注解,矩阵变量要绑定在路径变量中 @MatrixVariable("brand") List<String> brand, @PathVariable("path") String path) { //需要加上路径访问变量的注解 Map<String,Object> map = new HashMap<>(); map.put("low",low); map.put("brand",brand); map.put("path",path); return map; }

<a href="/cars/sell;low=34;brand=byd,audi,yd">MatrixVariable(矩阵变量)</a>

@GetMapping("/boss/{bossId}/{empId}")
    public Map bossmessage(@MatrixVariable(value = "age",pathVar = "bossId") Integer bossage,  //当传入的参数名一样时,需要哟波pathVar进行区分
                           @MatrixVariable(value = "age",pathVar = "empId") Integer empage) {
        Map<String,Object> map = new HashMap<>();
        map.put("bossage",bossage);
        map.put("empage",empage);
        return map;
    }

<a href="/boss/1;age=34/2;age=22">MatrixVariable(矩阵变量2)</a>