Servlet, Spring, Springboot에서 view단에 json보내주는법

1.Servlet에서는 GSON사용

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2.Spring에서는 @ResponseBody Map객체활용

(https://webcoding.tistory.com/entry/Spring-%EC%8A%A4%ED%94%84%EB%A7%81-RequestBody-ResponseBody-%EC%82%AC%EC%9A%A9%ED%95%98%EA%B8%B0-1)

JSON->MAP

@Controller
public class MainController {

    // home.jsp
    @RequestMapping(value = "/", method = RequestMethod.GET)
    public String home() {
        return "home";
    }
	
    @ResponseBody
    @RequestMapping(value = "/test", method = RequestMethod.POST)
    public void init(@RequestBody HashMap<String, Object> map) {
    	System.out.println(map);
    	// {name=kim, age=30} 출력
    }
}

JSON -> 객체

@Controller
public class MainController {

    // home.jsp
    @RequestMapping(value = "/", method = RequestMethod.GET)
    public String home() {
        return "home";
    }
	
    @ResponseBody
    @RequestMapping(value = "/test", method = RequestMethod.POST)
    public void init(@RequestBody UserVO userVO) {
        
    	userVO.getName(); // "kim"
        userVO.getAge(); // 30
    }
}

*물론 Spring에서도 GSON사용가능하다 (https://webcoding.tistory.com/entry/Spring-%EC%8A%A4%ED%94%84%EB%A7%81%EC%97%90%EC%84%9C-Gson%EC%9D%84-%EC%9D%B4%EC%9A%A9%ED%95%98%EC%97%AC-ajax-%ED%86%B5%EC%8B%A0%ED%95%98%EA%B8%B0)

 

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3.SpringBoot @RestController로 바로해결 (@RestController == Spring의 @Controller + @ResponseBody 역할)

@RestController
public class HelloController {
 
    @GetMapping(path =  "/hello-world-bean")
    public HelloBean helloWorldBean(){
        return new HelloBean("Hello World"); //json형식으로 반환
    }
}

{

    "message": "Hello World"

}