Spring Boot로 RESTful Service 만들기

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관리 메뉴

사랑해 마니마니

Spring Boot로 RESTful Service 만들기 본문

카테고리 없음

Spring Boot로 RESTful Service 만들기

분리불안증후군 2018. 10. 6. 09:35

Engin Yöyen 의 Building Microservices with Spring Boot 따라 해보기: 책 참 좋다.

0. Spring Boot 프로젝트 만들어 보자

start.spring.io

grade project
java: 1.8
Spring boot: 2.0.5
group: com.example
artifact: http-programming
dependencies: Web, Lombok

Lombok 설치하기

IntelliJ plugin
IntelliJ IDEA > Preferences > Build, Execution, Deployment > Compile > Annotation Processes > Enable Annotation Processing

Git 설정하기

root에서 git init 실행

.gitignore 파일 만들기

gitignore.io 사이트에서
java, gradle, git, intellij를 항목으로 .gitignore 파일 생성하기
.gitignore 파일 만들고 git init

Project 실행하기

Terminal에서 gradle bootRun
Control + Shift + R

프로젝트 Packaging

gradle build
java -jar build/libs/java -jar build/libs/http-programming-0.0.1-SNAPSHOT.jar

@SpringBootApplication

HttpProgrammingApplication.java 파일을 ApplicationStarter.java로 rename

package com.example;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class ApplicationStarter {

   public static void main(String[] args) {
      SpringApplication.run(ApplicationStarter.class, args);
   }
}

package com.example.controller;
import org.springframework.web.bind.annotation.PathVariable; 
import org.springframework.web.bind.annotation.RequestMapping; 
import org.springframework.web.bind.annotation.RestController;

@RestController 
public class HelloController {
  @RequestMapping(value = "/hello/{name}") 
  String hello(@PathVariable String name) {
	return String.format("Hello %s", name);
  }
}

브라우져에서 http://localhost:8080/hello/min 로 접근하면 화면상에 min 출력됨

1. Http Request와 Http Response 메시지 to Spring Annotation

http://localhost:8080/compute/function/sum http://localhost:8080/compute/function/sum?limit=5 http://localhost:8080/compute/function/max?limit=8 http://localhost:8080/compute/function/min?limit=6

2. Controller

Postman을 설치한 후에 Chrome에서 주소창에 chrome://apps 을 실행하고, postman 실행

NOT_IMPLEMENTED

public static final HttpStatus NOT_IMPLEMENTED

501 Not Implemented

User model 추가 및 /user에 대한 Get Request 구현

package com.example.model;

import lombok.*;

@NoArgsConstructor
@AllArgsConstructor
@Getter
@Setter
@ToString
public class User {
    private Long id;
    private String username;
}

package com.example.controller;

import com.example.model.User;
import org.springframework.http.HttpStatus;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.*;

import java.util.Arrays;
import java.util.List;


@Controller
public class Users {

    @ResponseBody
    @GetMapping("/users")
    List<User> getAll() {
        User jane = new User(1L, "Jane");
        User john = new User(2L, "John");
        return Arrays.asList(jane, john);
    }

    @ResponseStatus(HttpStatus.NOT_IMPLEMENTED)
    @RequestMapping(value = "/users/jane", method = RequestMethod.GET)
    void get() {
    }

    @ResponseStatus(HttpStatus.NOT_IMPLEMENTED)
    @RequestMapping(value = "/users", method = RequestMethod.PUT)
    void put() {
    }

    @ResponseStatus(HttpStatus.NOT_IMPLEMENTED)
    @RequestMapping(value = "/users/jane", method = RequestMethod.POST)
    void post() {
    }

    @ResponseStatus(HttpStatus.NOT_IMPLEMENTED)
    @RequestMapping(value = "/users/jane", method = RequestMethod.DELETE)
    void delete() {
    }

}

Terminal에서 curl로 확인해 보면

~: $ curl -X GET http://localhost:8080/users -i

HTTP/1.1 200
Content-Type: application/json;charset=UTF-8
Transfer-Encoding: chunked
Date: Sun, 07 Oct 2018 11:53:46 GMT

[{"id":1,"username":"Jane"},{"id":2,"username":"John"}]

@RestController 사용하기

@RestController 어노테이션은 Spring 4.0에 도입됨

@RestController = @Controller + @ResponseBody

3. Request Body 관련 기능 만들기

package com.example.controller;

import com.example.model.User;
import org.springframework.http.HttpStatus;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.*;

import java.util.Arrays;
import java.util.List;


@RestController
@RequestMapping("/users")
public class Users {

    @GetMapping
    List<User> getAll() {
        User jane = new User(1L, "Jane");
        User john = new User(2L, "John");
        return Arrays.asList(jane, john);
    }

    @ResponseStatus(HttpStatus.NOT_IMPLEMENTED)
    @GetMapping(value = "/jane")
    void get() {
    }

    @ResponseStatus(HttpStatus.NOT_IMPLEMENTED)
    @PutMapping
    void put() {
    }

    @PostMapping(value = "/jane")
    User post(@RequestBody User user) {
        return user;
    }

    @ResponseStatus(HttpStatus.NOT_IMPLEMENTED)
    @DeleteMapping("/jane")
    void delete() {
    }

}

Postman에서 Request를

{
"id": 198555,
"username": "Jane"
}

보내면

Response가 Status : 200 OK로 해서 아래와 같이 Return 됨.

{
"id": 198555,
"username": "Jane"
}

여기서 { "_id_": 198555, "_username_": "Jane" }와 같이 잘못된 파라메터로 보내면

Response가 Status : 200 OK, { "id": null, "username": null } 로 리턴됨

Status : 200 OK가 아닌 에러가 출력되도록 하기 위하서는

application.properties에

spring.jackson.deserialization.fail_on_unknown_properties=true

를 셋팅해야 한다

다시 { "_id_": 198555, "_username_": "Jane" } 로 Reqeust를 보내면

{
"timestamp": "2018-10-07T12:17:27.746+0000",
"status": 400,
"error": "Bad Request",
"message": "JSON parse error: Unrecognized field \"-id\" (class com.example.model.User), not marked as ignorable; nested exception is com.fasterxml.jackson.databind.exc.UnrecognizedPropertyException: Unrecognized field \"-id\" (class com.example.model.User), not marked as ignorable (2 known properties: \"id\", \"username\"])\n at [Source: (PushbackInputStream); line: 2, column: 16] (through reference chain: com.example.model.User[\"-id\"])",
"path": "/users/jane"
}

를 출력함.

4. URI Template

scheme:[//[user:password@]host[:port]][/]path[?query][#fragment]

GET /users/:username/repos?page=2&size=10

http://example.com/users/jane/repos?page=2&size=10

Path Variable 처리하기

http://example.com/users/jane/repos?page=2&size=10과 같은 request를 이제 처리해 보자

@PathVariable 어노테이션을 이용하여 path variable을 URI 매핑하는 데 이용해 보자

http://example.com/users/jane/repos?page=2&size=10에서 jane을 Path Variable로 받을 수 있도록

package com.example.controller;

import com.example.model.User;
import org.springframework.http.HttpStatus;
import org.springframework.web.bind.annotation.*;

import java.util.Arrays;
import java.util.List;


@RestController
@RequestMapping("/users")
public class Users {

    @GetMapping
    List<User> getAll() {
        User jane = new User(1L, "Jane");
        User john = new User(2L, "John");
        return Arrays.asList(jane, john);
    }

    @GetMapping("/{username}")
    User get(@PathVariable String username) {
        return new User(1L, username);
    }

    @ResponseStatus(HttpStatus.NOT_IMPLEMENTED)
    @PutMapping
    void put() {
    }

    @PostMapping(value = "/jane")
    User post(@RequestBody User user) {
        return user;
    }

    @ResponseStatus(HttpStatus.NOT_IMPLEMENTED)
    @DeleteMapping("/jane")
    void delete() {
    }

}

min: ~$ curl -X GET http://localhost:8080/users/anyone -i
HTTP/1.1 200
Content-Type: application/json;charset=UTF-8
Transfer-Encoding: chunked
Date: Mon, 08 Oct 2018 15:49:06 GMT

{"id":1,"username":"anyone"}

Query String 처리하기

http://example.com/users/jane/repos?page=2&size=10에서 page, size 값을 Variable로 받을 수 있도록

package com.example.controller;

import com.example.model.User;
import lombok.extern.slf4j.Slf4j;
import org.springframework.http.HttpStatus;
import org.springframework.web.bind.annotation.*;

import java.util.Arrays;
import java.util.List;


@RestController
@RequestMapping("/users")
@Slf4j
public class Users {

    @GetMapping
    List<User> getAll(@RequestParam(value = "page", required = false) Integer page,
                      @RequestParam(value = "size", required = false) Integer size) {

        log.info(String.format("Requested all users with page %d and size %d ", page, size));

        User jane = new User(1L, "Jane");
        User john = new User(2L, "John");
        return Arrays.asList(jane, john);
    }

    @GetMapping("/{username}")
    User get(@PathVariable String username) {
        return new User(1L, username);
    }

    @ResponseStatus(HttpStatus.NOT_IMPLEMENTED)
    @PutMapping
    void put() {
    }

    @PostMapping(value = "/jane")
    User post(@RequestBody User user) {
        return user;
    }

    @ResponseStatus(HttpStatus.NOT_IMPLEMENTED)
    @DeleteMapping("/jane")
    void delete() {
    }

}

@RequestParam으로 "page"값과 "size" 변수를 각각 Integer page, Integer size값으로 받는다.

로그를 찍기 위해서 Lombok의 @Slf4j 어노테이션을 사용하고 log.info(...)로 로그 출력

Postman에서 GET 방식으로 http://localhost:8080/users?page=2&size=10을 던지면

Console(Log)에 INFO 17003 --- [nio-8080-exec-2] com.example.controller.Users : Requested all users with page 2 and size 10 이 출력됨

request = false 대신 Java 1.8 의 java.util.Optinal을 사용하면

List<User> getAll(@RequestParam(value = "page") Optional<Integer> page,
                  @RequestParam(value = "size") Optional<Integer> size) {

    log.info(String.format("Requested all users with page %d and size %d ", page.orElse(null), size.orElse(null)));

    User jane = new User(1L, "Jane");
    User john = new User(2L, "John");
    return Arrays.asList(jane, john);
}

5. HTTP Response 만들기

RequestEntity를 사용한다면

도메인 객체를 return하지 않고
좀더 flexisble한 프로그램을 원하거나
다른 형태의 response body를 원한다면
또는 error를 throw하기를 원한다면

package com.example.controller;

import com.example.model.User;
import lombok.extern.slf4j.Slf4j;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.*;

import java.util.Arrays;
import java.util.List;
import java.util.Optional;


@RestController
@RequestMapping("/users")
@Slf4j
public class Users {

    @GetMapping
    List<User> getAll(@RequestParam(value = "page") Optional<Integer> page,
                           @RequestParam(value = "size") Optional<Integer> size) {

        log.info(String.format("Requested all users with page %d and size %d ", page.orElse(null), size.orElse(null)));

        User jane = new User(1L, "Jane");
        User john = new User(2L, "John");
        return Arrays.asList(jane, john);
    }

    @GetMapping("/{username}")
    User get(@PathVariable String username) {
        return new User(1L, username);
    }

    @PutMapping
    ResponseEntity<?> put(@RequestBody User user) {
        if (user.getUsername() != null && user.getUsername().length() < 5) {
            return new ResponseEntity(HttpStatus.UNPROCESSABLE_ENTITY);
        } 
        
        //create user first than
        return new ResponseEntity(user, HttpStatus.CREATED); 
    }

    @PostMapping(value = "/jane")
    User post(@RequestBody User user) {
        return user;
    }

    @ResponseStatus(HttpStatus.NOT_IMPLEMENTED)
    @DeleteMapping("/jane")
    void delete() {
    }

}

Postman으로

PUT method
URI http://localhost:8080/users
Request Body { "id" : 198555, "username" : "Jane" }

요청하면 Status: 422 Unprocessable Entity (WebDAV) (RFC 4918) 에러 상태임

만약 Request Body에서 "username" : "Jane.hi"로 user.getUsername.length()가 5보다 크면 Status: 201 Created 상태가 출력됨

다른 형태의 Response Body

오류가 발생하면 Http Status code (422) 정보만으로는 부족하다. 그래서 error message 을 ResponseEntity에 실어 보내는 방법을 사용한다.

먼저 Error Message를 담을 모델을 만들자

package com.example.model;

import lombok.AllArgsConstructor;
import lombok.Getter;

@AllArgsConstructor
@Getter
public class ErrorMessage {
    private String message;
    private String error;
}

package com.example.controller;

import com.example.model.ErrorMessage;
import com.example.model.User;
import lombok.extern.slf4j.Slf4j;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.*;

import java.util.Arrays;
import java.util.List;
import java.util.Optional;


@RestController
@RequestMapping("/users")
@Slf4j
public class Users {

    @GetMapping
    List<User> getAll(@RequestParam(value = "page") Optional<Integer> page,
                      @RequestParam(value = "size") Optional<Integer> size) {

        log.info(String.format("Requested all users with page %d and size %d ", page.orElse(null), size.orElse(null)));

        User jane = new User(1L, "Jane");
        User john = new User(2L, "John");
        return Arrays.asList(jane, john);
    }

    @GetMapping("/{username}")
    User get(@PathVariable String username) {
        return new User(1L, username);
    }

    @PutMapping
    ResponseEntity<?> put(@RequestBody User user) {
        if (user.getUsername() != null && user.getUsername().length() < 5) {
            ErrorMessage error = new ErrorMessage("Validation Failed", "User name is less than 5 character");
            return new ResponseEntity(error, HttpStatus.UNPROCESSABLE_ENTITY);
        }

        //create user first than
        return new ResponseEntity(user, HttpStatus.CREATED);
    }

    @PostMapping(value = "/jane")
    User post(@RequestBody User user) {
        return user;
    }

    @ResponseStatus(HttpStatus.NOT_IMPLEMENTED)
    @DeleteMapping("/jane")
    void delete() {
    }

}

앞에서와 같이 Postman으로

PUT method
URI http://localhost:8080/users
Request Body { "id" : 198555, "username" : "Jane" }

요청하면 Status: 422 Unprocessable Entity (WebDAV) (RFC 4918) 에러 상태와 함께 response body에

{
    "message": "Valication Failed",
    "error": "User name is less than 5 character"
}

Response Header에 정보 보내기

HTTP status와 body와 함께 response header도 ResponseEntity에 실어 보낼수 있음.

(e.g. Rate-Limiting 정보)

package com.example.controller;

import com.example.model.ErrorMessage;
import com.example.model.User;
import lombok.extern.slf4j.Slf4j;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.*;

import java.util.Arrays;
import java.util.List;
import java.util.Optional;


@RestController
@RequestMapping("/users")
@Slf4j
public class Users {

    @GetMapping
    List<User> getAll(@RequestParam(value = "page") Optional<Integer> page,
                      @RequestParam(value = "size") Optional<Integer> size) {

        log.info(String.format("Requested all users with page %d and size %d ", page.orElse(null), size.orElse(null)));

        User jane = new User(1L, "Jane");
        User john = new User(2L, "John");
        return Arrays.asList(jane, john);
    }

    @GetMapping("/{username}")
    ResponseEntity<?> get(@PathVariable String username) {
        User user = new User(1L, username);
        HttpHeaders responseHeaders = new HttpHeaders();
        responseHeaders.set("X-RateLimit-Limit", "1000");
        responseHeaders.set("X-RateLimit-Remaining", "500");
        responseHeaders.set("X-RateLimit-Reset", "1457020923");
        return new ResponseEntity(user, responseHeaders, HttpStatus.OK);
    }

    @PutMapping
    ResponseEntity<?> put(@RequestBody User user) {
        if (user.getUsername() != null && user.getUsername().length() < 5) {
            ErrorMessage error = new ErrorMessage("Validation Failed", "User name is less than 5 character");
            return new ResponseEntity(error, HttpStatus.UNPROCESSABLE_ENTITY);
        }

        //create user first than
        return new ResponseEntity(user, HttpStatus.CREATED);
    }

    @PostMapping(value = "/jane")
    User post(@RequestBody User user) {
        return user;
    }

    @ResponseStatus(HttpStatus.NOT_IMPLEMENTED)
    @DeleteMapping("/jane")
    void delete() {
    }

}

Postman으로 GET, http://localhost:8080/users/jane을 보내면

content-type →application/json;charset=UTF-8
date →Tue, 09 Oct 2018 00:36:31 GMT
transfer-encoding →chunked
x-ratelimit-limit →1000
x-ratelimit-remaining →500
x-ratelimit-reset →1457020923

ResponseEntity

public ResponseEntity(@Nullable
                      T body,
                      @Nullable
                      MultiValueMap<java.lang.String,java.lang.String> headers,
                      HttpStatus status)

Create a new HttpEntity with the given body, headers, and status code.

Parameters:: body - the entity body; headers - the entity headers; status - the status code

6. Request Header 사용

Corelation ID등을 HTTP Request등을 Header에 실어 보낼 때 사용

mendetory 나 optional로 header를 받을 것인지를 선택할 수 있음
mendetory로 설정했는 데 HTTP Request에 필요로 하는 값이 넘어 오지 않을 경우 status code 400(Bad Request) return

package com.example.controller;

import com.example.model.ErrorMessage;
import com.example.model.User;
import lombok.extern.slf4j.Slf4j;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.util.MultiValueMap;
import org.springframework.web.bind.annotation.*;

import java.util.Arrays;
import java.util.List;
import java.util.Optional;


@RestController
@RequestMapping("/users")
@Slf4j
public class Users {

    @GetMapping
    List<User> getAll(@RequestParam(value = "page") Optional<Integer> page,
                      @RequestParam(value = "size") Optional<Integer> size) {

        log.info(String.format("Requested all users with page %d and size %d ", page.orElse(null), size.orElse(null)));

        User jane = new User(1L, "Jane");
        User john = new User(2L, "John");
        return Arrays.asList(jane, john);
    }

    @GetMapping("/{username}")
    ResponseEntity<?> get(@PathVariable String username) {
        User user = new User(1L, username);
        HttpHeaders responseHeaders = new HttpHeaders();
        responseHeaders.set("X-RateLimit-Limit", "1000");
        responseHeaders.set("X-RateLimit-Remaining", "500");
        responseHeaders.set("X-RateLimit-Reset", "1457020923");
        return new ResponseEntity(user, responseHeaders, HttpStatus.OK);
    }

    @PutMapping
    ResponseEntity<?> put(@RequestBody User user) {
        if (user.getUsername() != null && user.getUsername().length() < 5) {
            ErrorMessage error = new ErrorMessage("Validation Failed", "User name is less than 5 character");
            return new ResponseEntity(error, HttpStatus.UNPROCESSABLE_ENTITY);
        }

        //create user first than
        return new ResponseEntity(user, HttpStatus.CREATED);
    }

    @PostMapping(value = "/jane")
    User post(@RequestBody User user) {
        return user;
    }

    @ResponseStatus(HttpStatus.NO_CONTENT)
    @DeleteMapping("/jane")
    void delete(@PathVariable String username,
                @RequestHeader MultiValueMap<String, String> headers) {
        headers.forEach((k, v) -> log.info(String.format("%s : %s ", k, v)));
        //here is where the user will be deleted
    }

}

curl -i -X DELETE http://localhost:8080/users/jane을 보내면

HTTP/1.1 500
Content-Type: application/json;charset=UTF-8
Transfer-Encoding: chunked
Date: Tue, 09 Oct 2018 00:51:18 GMT
Connection: close

{
  "timestamp":"2018-10-09T00:51:18.401+0000",
  "status":500,"error":"Internal Server Error",
  "message":"Missing URI template variable 'username' for method parameter of type String",
  "path":"/users/jane"
}

? Engin yoyen 책에서는 400 Bad Request를 return 한다고 했는 데 해보니 Status code가 500으로 return된다.

7. Exception 처리하기

앞에서 validaion Exception이 발생했을 때 Status code 422 Unprocessable Entity를 return하도록 처리했는 데 .. 좀더 개선해 보자

Spring에서는 Controller에서 Exception이 발생했을 때 2가지 방식으로 처리함

ExceptionHandler: exception이 발생(throw)했을 때 항상 call이 됨
@ControllerAdvice: @RequestMapping에 대한 exception 처리

package com.example.exception;

public class ValidationException extends Exception {
    public ValidationException(String message) {
        super(message);
    }
}

package com.example.controller;

import com.example.exception.ValidationException;
import com.example.model.ErrorMessage;
import com.example.model.User;
import lombok.extern.slf4j.Slf4j;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.util.MultiValueMap;
import org.springframework.web.bind.annotation.*;

import java.util.Arrays;
import java.util.List;
import java.util.Optional;


@RestController
@RequestMapping("/users")
@Slf4j
public class Users {

    @GetMapping
    List<User> getAll(@RequestParam(value = "page") Optional<Integer> page,
                      @RequestParam(value = "size") Optional<Integer> size) {

        log.info(String.format("Requested all users with page %d and size %d ", page.orElse(null), size.orElse(null)));

        User jane = new User(1L, "Jane");
        User john = new User(2L, "John");
        return Arrays.asList(jane, john);
    }

    @GetMapping("/{username}")
    ResponseEntity<?> get(@PathVariable String username) {
        User user = new User(1L, username);
        HttpHeaders responseHeaders = new HttpHeaders();
        responseHeaders.set("X-RateLimit-Limit", "1000");
        responseHeaders.set("X-RateLimit-Remaining", "500");
        responseHeaders.set("X-RateLimit-Reset", "1457020923");
        return new ResponseEntity(user, responseHeaders, HttpStatus.OK);
    }

    @PutMapping
    ResponseEntity<?> put(@RequestBody User user) throws Exception{
        if (user.getUsername() != null && user.getUsername().length() < 5) {
            //ErrorMessage error = new ErrorMessage("Validation Failed", "User name is less than 5 character");
            //return new ResponseEntity(error, HttpStatus.UNPROCESSABLE_ENTITY);
            throw new ValidationException("User name is less than 5 character");
        }

        //create user first than
        return new ResponseEntity(user, HttpStatus.CREATED);
    }

    @PostMapping(value = "/jane")
    User post(@RequestBody User user) {
        return user;
    }

    @ResponseStatus(HttpStatus.NO_CONTENT)
    @DeleteMapping("/jane")
    void delete(@PathVariable String username,
                @RequestHeader MultiValueMap<String, String> headers) {
        headers.forEach((k, v) -> log.info(String.format("%s : %s ", k, v)));
        //here is where the user will be deleted
    }

}

Postman으로 PUT, http://localhost:8080/users를 던지면

connection →close
content-type →application/json;charset=UTF-8
date →Tue, 09 Oct 2018 01:13:56 GMT
transfer-encoding →chunked

Status: 500 Internal Server Error

{
    "timestamp": "2018-10-09T01:13:56.258+0000",
    "status": 500,
    "error": "Internal Server Error",
    "message": "User name is less than 5 character",
    "path": "/users"
}

2018-10-09 10:32:58.252 ERROR 19394 --- [nio-8080-exec-1] o.a.c.c.C.[.[.[/].[dispatcherServlet]    : Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is com.example.exception.ValidationException: User name is less than 5 character] with root cause

com.example.exception.ValidationException: User name is less than 5 character
	at com.example.controller.Users.put(Users.java:49) ~[classes/:na]
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_121]
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_121]
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_121]
	at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_121]
	at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:209) ~[spring-web-5.0.9.RELEASE.jar:5.0.9.RELEASE]
	at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:136) ~[spring-web-5.0.9.RELEASE.jar:5.0.9.RELEASE]
    ....

Status Code가 우리가 원하는 코드가 아님. 그래서 재대로 동작하기 위해 @ControllerAdvice를 사용하여 Exception 처리 Class를 만들어

package com.example.controller;

import com.example.exception.ValidationException;
import com.example.model.ErrorMessage;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.ControllerAdvice;
import org.springframework.web.bind.annotation.ExceptionHandler;

@ControllerAdvice
class ExceptionHandlerAdvice {
    @ExceptionHandler(value = ValidationException.class)
    public ResponseEntity validationExceptionHandler(Exception e) {
        ErrorMessage error = new ErrorMessage("Validation Failed", e.getMessage());
        return new ResponseEntity(error, HttpStatus.UNPROCESSABLE_ENTITY);
    }
}

content-type →application/json;charset=UTF-8
date →Tue, 09 Oct 2018 01:30:48 GMT
transfer-encoding →chunked

Status: 422 Unprocessable Entity (WebDAV) (RFC 4918)

{
    "message": "Validation Failed",
    "error": "User name is less than 5 character"
}

사랑해 마니마니

사랑해 마니마니

Spring Boot로 RESTful Service 만들기 본문

Spring Boot로 RESTful Service 만들기

0. Spring Boot 프로젝트 만들어 보자

start.spring.io

Lombok 설치하기

Git 설정하기

.gitignore 파일 만들기

Project 실행하기

프로젝트 Packaging

@SpringBootApplication

1. Http Request와 Http Response 메시지 to Spring Annotation

2. Controller

User model 추가 및 /user에 대한 Get Request 구현

@RestController 사용하기

3. Request Body 관련 기능 만들기

4. URI Template

Path Variable 처리하기

Query String 처리하기

5. HTTP Response 만들기

RequestEntity를 사용한다면

다른 형태의 Response Body

Response Header에 정보 보내기

ResponseEntity

6. Request Header 사용

7. Exception 처리하기

8. HTTP Caching (Comming soon)

Time-based Cache Headers

Conditional Cache Headers

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