Почему Spring не видит MySql

Question

MainController 
package com.example.ordersbackend.controllers 
 
import org.springframework.beans.factory.annotation.Autowired 
import org.springframework.stereotype.Controller 
import org.springframework.web.bind.annotation.GetMapping 
import org.springframework.web.bind.annotation.ResponseBody

@Controller 
class MainController { 
    @Autowired 
    private lateinit var postRepository: PostRepository 
 
    @GetMapping(&#34;/&#34;) 
    @ResponseBody 
    open fun getAllUsers(): MutableIterable<Any?> { 
        // This returns a JSON or XML with the users 
        return postRepository.findAll() 
    } 
} 
 
PostRepository 
 
package com.example.ordersbackend.controllers; 
 
import org.springframework.data.repository.CrudRepository; 
 
public interface PostRepository extends CrudRepository { 
}

Post 
package com.example.ordersbackend.models 
 
import jakarta.persistence.* 
 
@Entity 
@Table(name = &#34;posts&#34;) 
class Post {
    @Id  
 
    @GeneratedValue(strategy = GenerationType.AUTO)  
 
    private var id: Short? = null

var title: String = &#34;&#34; 
 
    fun getId(): Short? { 
        return id 
    } 
 
    fun setId(id: Short) { 
        this.id = id 
    } 
 
    fun getTitle(): String { 
        return title 
    } 
 
    fun setTitle(title: String) { 
        this.title = title 
    } 
} 
 
application.properties
spring.jpa.hibernate.ddl-auto=update 
spring.datasource.url=jdbc:mysql://${MYSQL_HOST:localhost}:3306/posts 
spring.datasource.username= 
spring.datasource.password= 
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver 
spring.jpa.show-sql: true 
 
Ошибки 
java.lang.IllegalArgumentException: Could not resolve domain type of interface com.example.ordersbackend.controllers.PostRepository

Оракул · Answer

public interface PostRepository extends CrudRepository

V̲i̲s̲t̲a̲s̲t̲e̲r̲ · Answer

Добавить параметр дженерика с указанием типа: package com.example.ordersbackend.controllers; 
 
import org.springframework.data.repository.CrudRepository; 
import com.example.ordersbackend.models.Post; 
 
public interface PostRepository extends CrudRepository { 
} 
 Проверить настройки соединения spring.jpa.hibernate.ddl-auto=update 
spring.datasource.url=jdbc:mysql://localhost:3306/posts 
spring.datasource.username=root 
spring.datasource.password=root 
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver 
spring.jpa.show-sql: true 
spring.jpa.database-platform=org.hibernate.dialect.MySQLDialect