Server to server

client의 RestTemplateService.java

post 부분 넣기

package com.example.client.service;

import com.example.client.dto.UserRequest;
import com.example.client.dto.UserResponse;
import org.apache.catalina.User;
import org.springframework.http.ResponseEntity;
import org.springframework.stereotype.Service;
import org.springframework.web.client.RestTemplate;
import org.springframework.web.util.UriComponentsBuilder;

import java.net.URI;

@Service
public class RestTemplateService {

    //http://localhost/api/server/hello
    //response

    public UserResponse hello(){
        URI uri = UriComponentsBuilder
                .fromUriString("http://localhost:9090")
                .path("/api/server/hello")
                .queryParam("name","Hyerin")
                .queryParam("age",26)
                .encode()
                .build()
                .toUri();

        System.out.println(uri.toString());

        RestTemplate restTemplate = new RestTemplate();

        ResponseEntity<UserResponse> result = restTemplate.getForEntity(uri,UserResponse.class);

        System.out.println(result.getStatusCode());
        System.out.println(result.getBody());

        return result.getBody();
    }

    public UserResponse post(){

        //http://localhost:9090/api/server/user/{userId}/name{userName}
        URI uri = UriComponentsBuilder
                .fromUriString("http://localhost:9090")
                .path("/api/server/user/{userId}/name{userName}")
                .encode()
                .build()
                .expand(100) //pathvariable 하나씩 매칭
                .expand("steve")
                .toUri();
        System.out.println(uri);

        // post이기 때문에 http body가 필요하다
        // http body -> object -> object mapper -> json으로 바꿈 -> rest template -> http body json에 넣어줌
        UserRequest req = new UserRequest();
        req.setName("steve");
        req.setAge(10);
        
        //Rest template로 쏘기
    }
}

dto - UserRequest 만들기

package com.example.client.dto;

public class UserRequest {

    private String name;
    private int age;

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    @Override
    public String toString() {
        return "UserResponse{" +
                "name='" + name + '\'' +
                ", age=" + age +
                '}';
    }
}

post로 보낼 때도 마찬가지로,

1. 주소 만들기

2. 내가 보내고 싶은 Request body data를 json으로 만드는 것이 아니라 object로 만들기

UserRequest req = new UserRequest();

3. object mapper가 자연적으로 json으로 바꿔주고

4. rest template에서 body에 json을 넣어서 쏠 것이다.

5. 그리고 응답을 무엇으로 받을 지 지정하면 된다.

RestTemplate restTemplate = new RestTemplate();
ResponseEntity<UserResponse> response = restTemplate.postForEntity(uri,req,UserResponse.class);

package com.example.client.service;

import com.example.client.dto.UserRequest;
import com.example.client.dto.UserResponse;
import org.apache.catalina.User;
import org.springframework.http.ResponseEntity;
import org.springframework.stereotype.Service;
import org.springframework.web.client.RestTemplate;
import org.springframework.web.util.UriComponentsBuilder;

import java.net.URI;

@Service
public class RestTemplateService {

    //http://localhost/api/server/hello
    //response

    public UserResponse hello(){
        URI uri = UriComponentsBuilder
                .fromUriString("http://localhost:9090")
                .path("/api/server/hello")
                .queryParam("name","Hyerin")
                .queryParam("age",26)
                .encode()
                .build()
                .toUri();

        System.out.println(uri.toString());

        RestTemplate restTemplate = new RestTemplate();

        ResponseEntity<UserResponse> result = restTemplate.getForEntity(uri,UserResponse.class);

        System.out.println(result.getStatusCode());
        System.out.println(result.getBody());

        return result.getBody();
    }

    public UserResponse post(){

        //http://localhost:9090/api/server/user/{userId}/name{userName}
        URI uri = UriComponentsBuilder
                .fromUriString("http://localhost:9090")
                .path("/api/server/user/{userId}/name/{userName}") //PathVariable 처리하는 방법
                .encode()
                .build()
                .expand(100,"steve") //pathvariable 하나씩 매칭
                .toUri();
        System.out.println(uri);

        // post이기 때문에 http body가 필요하다
        // http body -> object -> object mapper -> json으로 바꿈 -> rest template -> http body json에 넣어줌
        UserRequest req = new UserRequest();
        req.setName("steve");
        req.setAge(10);

        //Rest template로 쏘기
        RestTemplate restTemplate = new RestTemplate();
        ResponseEntity<UserResponse> response = restTemplate.postForEntity(uri,req,UserResponse.class);
        //uri 라는 주소에, req(request body)를 만들어서, 응답은 UserResponse로 받을 것이라는 뜻

        System.out.println(response.getStatusCode());
        System.out.println(response.getHeaders());
        System.out.println(response.getBody());

        return response.getBody();
    }
}

서버에서 받아주는 것을 만들어보자

package com.example.server.controller;

import com.example.server.dto.User;
import lombok.extern.slf4j.Slf4j;
import org.springframework.web.bind.annotation.*;

@Slf4j
@RestController
@RequestMapping("/api/server")
public class ServerApiController {

    @GetMapping("/hello")
    public User hello(@RequestParam String name, @RequestParam int age){
        User user = new User();
        user.setAge(age); //echo 방식으로 동작할 것이기 때문에 age, name 넣자
        user.setName(name);
        return user;
    }

    @PostMapping("/user/{userId}/name/{userName}") //변경되는 값을 변수로 매칭해주자 (아래 @PathVariable로)
    public User post(@RequestBody User user,@PathVariable int userId,@PathVariable String userName){ //@RequestBody로 User를 받는다
        log.info("client req : {}",user); //user의 toString이 괄호에 들어간다는 뜻

        log.info("userId : {}, userName : {}",userId,userName);

        return user;
    }
}

package com.example.client.controller;

import com.example.client.dto.UserResponse;
import com.example.client.service.RestTemplateService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
@RequestMapping("/api/client")
public class ApiController {

    private final RestTemplateService restTemplateService;

    public ApiController(RestTemplateService restTemplateService) {
        this.restTemplateService = restTemplateService;
    }

    @GetMapping("/hello")
    public UserResponse getHello(){

        return restTemplateService.post(); //post 메소드 호출하기
    }
}

결과

서버 측 결과

서버가 어떻게 응답을 줄 지 모르겠을 때,

어떠한 값이 잘못 와서 뭔가 오류가 난 것 같을 때,

String으로 받아보자!

    public void post(){
        
        URI uri = UriComponentsBuilder
                .fromUriString("http://localhost:9090")
                .path("/api/server/user/{userId}/name/{userName}")
                .encode()
                .build()
                .expand(100,"steve") 
                .toUri();
        System.out.println(uri);
        
        UserRequest req = new UserRequest();
        req.setName("steve");
        req.setAge(10);
        
        RestTemplate restTemplate = new RestTemplate();
        ResponseEntity<String> response = restTemplate.postForEntity(uri,req,String.class);

        System.out.println(response.getStatusCode());
        System.out.println(response.getHeaders());
        System.out.println(response.getBody());

        //return response.getBody(); 없애버렷
    }

package com.example.client.controller;

import com.example.client.dto.UserResponse;
import com.example.client.service.RestTemplateService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
@RequestMapping("/api/client")
public class ApiController {

    private final RestTemplateService restTemplateService;

    public ApiController(RestTemplateService restTemplateService) {
        this.restTemplateService = restTemplateService;
    }

    @GetMapping("/hello")
    public UserResponse getHello(){

        restTemplateService.post();
        return new UserResponse();
    }
}

결과

json 형태의 toString이 넘어옴(문자열로)

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