인프런 커뮤니티 질문&답변

두 가지 질문이 있습니다.

1. EntityModel을 찾을 수 없다고 나오는데 도움을 받을 수 있을까요??

2. 공식문서에는 RepresentationModel를 상속하여 기능을 추가하라고 가이드하고 있는데, EntityModel와 다른가요?

1. cannot resolve symbol 'EntityModel'

제 코드와 설정은 아래와 같습니다.

build.gradle

plugins {
    id 'java'
    id 'org.springframework.boot' version '3.0.0'
    id 'io.spring.dependency-management' version '1.1.0'
}

group = 'com.example'
version = '0.0.1-SNAPSHOT'
sourceCompatibility = '17'

repositories {
    mavenCentral()
}

dependencies {
    // web 라이브러리
    implementation 'org.springframework.boot:spring-boot-starter-web'
    // JPA
    implementation 'org.springframework.boot:spring-boot-starter-data-jpa'
    // JDBC
    implementation 'org.springframework.boot:spring-boot-starter-jdbc'
    // 타임리프
    implementation 'org.springframework.boot:spring-boot-starter-thymeleaf'
    implementation 'nz.net.ultraq.thymeleaf:thymeleaf-layout-dialect'
    // TEST
    testImplementation 'org.springframework.boot:spring-boot-starter-test'
    developmentOnly 'org.springframework.boot:spring-boot-devtools'
    // VALIDATION
    implementation 'org.springframework.boot:spring-boot-starter-validation'
    // 롬복
    compileOnly 'org.projectlombok:lombok'
    annotationProcessor 'org.projectlombok:lombok'
    runtimeOnly 'com.h2database:h2'
}

tasks.named('test') {
    useJUnitPlatform()
}

pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>3.1.0</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.example</groupId>
    <artifactId>dateanu</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>dateanu</name>
    <description>dateanu</description>
    <properties>
        <java.version>17</java.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-hateoas</artifactId>
        </dependency>


        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <optional>true</optional>
        </dependency>

        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
        </dependency>

        <dependency>
            <groupId>com.h2database</groupId>
            <artifactId>h2</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>

    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <version>2.4.4</version>
            </plugin>
        </plugins>
    </build>

</project>

application.properties

# DATABASE
spring.h2.console.enabled=true
spring.h2.console.path=/h2-console
# spring.datasource.url=jdbc:h2:~/local
spring.datasource.url=jdbc:h2:~/local;AUTO_SERVER=true
spring.datasource.driver-class-name=org.h2.Driver
spring.datasource.username=sa
spring.datasource.password=

# PORT
server.port=9090

# JPA
spring.jpa.properties.hibernate.dialect=org.hibernate.dialect.H2Dialect
# USE THIS
spring.jpa.hibernate.ddl-auto=create
# spring.jpa.hibernate.ddl-auto=update // OR THIS
# AVOID THIS
# spring.jpa.hibernate.ddl-auto=create
# spring.jpa.hibernate.ddl-auto=create-drop

spring.messages.basename=messages
spring.messages.fallback-to-system-locale=false

Controller

package com.example.dateanu.rest_api;

import jakarta.validation.Valid;
import lombok.RequiredArgsConstructor;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.*;
import org.springframework.web.servlet.support.ServletUriComponentsBuilder;

import java.net.URI;
import java.util.List;

@RestController
@RequiredArgsConstructor
public class UserController {
    private final UserDaoService service; // 싱글톤 객체를 생성자주입을 하기 위해 꼭 final이 붙어야한다.

    @GetMapping("/users")
    public List<User> retrieveAllUsers() {
        return service.findAll();
    }

    // GET /users/1
    @GetMapping("/users/{id}")
    public User retrieveUser(@PathVariable int id) {
        User user =  service.findOne(id);

        if(user == null){
            throw new UserNotFoundException(String.format("ID[%s] not found",id));
        }

        // HATEOAS


        return user;
    }

    @PostMapping("/users")
    public ResponseEntity<User> createUser(@Valid @RequestBody User user){
        User savedUser = service.save(user);

        URI location = ServletUriComponentsBuilder.fromCurrentRequest()
                .path("/{id}")
                .buildAndExpand(savedUser.getId())
                .toUri();

        return ResponseEntity.created(location).build();
    }


    @DeleteMapping("/users/{id}")
    public ResponseEntity<User> deleteUser(@PathVariable int id){
        User user = service.deleteById(id);

        if(user == null){
            throw new UserNotFoundException(String.format("ID[%s] not found"));
        }

        return new ResponseEntity<>(user, HttpStatus.OK);
    }

    @PutMapping("/users/{id}")
    public ResponseEntity<User> replaceUser(@PathVariable int id,@RequestBody User user){
        User replacedUser = service.replace(id,user);

        return new ResponseEntity<>(replacedUser, HttpStatus.OK);
    }

    @PatchMapping("/users/{id}")
    public ResponseEntity<User> updateUser(@PathVariable int id,@RequestBody User user){
        User updatedUser = service.update(id,user);

        return new ResponseEntity<>(updatedUser, HttpStatus.OK);
    }
}

어떤 것 때문인지 몇 시간을 구글링하고 디버깅해봐도 해결되지가 않네요 ㅠㅠ

** 2.4.4 version에 hateoas 의존성 추가했으며, Gradle, Maven 모두 refresh 하였습니다.

2.

공식문서에서는 RepresentationModel 을 상속받아 쓰게끔 가이드가 되어있는 것을 확인했습니다.

https://spring.io/guides/gs/rest-hateoas/

EntityModel을 사용하는 것과 다른 것인지, 어떤 것이 best practice 인지 알려주실 수 있나요??

** 이 또한 cannot resolve symbol 'representationmodel' 에러가 발생하네요 ㅠㅠ

감사합니다 :-)