RestFul 风格改变 URL 形式

比如之前是：http://localhost:8080/add?a=1&b=2

现在是：http://localhost:8080/add/a/b（全是斜杠）

package com.demo.controller;

import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMethod;

@Controller
public class RestFul {
    //@RequestMapping(value = "/add/{a}/{b}",method = RequestMethod.GET)
    @GetMapping("/add/{a}/{b}")
    public String test(@PathVariable String a,@PathVariable String b, Model model){
        String res = a + b;
        model.addAttribute("msg",res);
        return "test"; //test.jsp
    }
}

通过 @PathVariable 映射到 URL 上

所有的地址栏请求默认都是 HTTP GET 类型

同理，组合注解有：

@GetMapping() 、@PostMapping()

@PutMapping() 、@DeleteMapping() 、@PatchMapping()

ServletAPI：通过 HttpServletRequest 进行输出、实现重定向、实现转发

package com.demo.controller;

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

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

@Controller
public class Model {
    @RequestMapping("/model")
    public String test(HttpServletRequest request, HttpServletResponse response){
        HttpSession session = request.getSession();
        System.out.println(session.getId());
        return "test";
    }
}

response.senRedirect("/xx.jsp")  重定向

request.getRequestDispatcher("/WEB-INF/jsp/xx.jsp").forward(request,response)  转发

通过 Spring MVC 来实现转发和重定向，无需视图解析器

forward 转发（不改变 URL）、redirect 重定向（改变 URL）

package com.demo.controller;

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

@Controller
public class ModelTest {
    @RequestMapping("/model")
    public String test(Model model){
        model.addAttribute("msg","Model");

        //转发：不改变url
        //return "/WEB-INF/jsp/test.jsp";
        //return "forward:/WEB-INF/jsp/test.jsp";

        //重定向：改变url
        return "redirect:/index.jsp";
    }
}