IllegalStateException：找不到必需的标识符属性

Question

当我试图将一个对象保存到H2数据库时，我不断地得到这个异常。

我试图持久化的对象定义如下：

package mypackage.foo.core.jpa.domain;

@Entity
@Getter
@NoArgsConstructor
public class Task implements Serializable {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Setter
    private Long id;

    private String name;
    private String description;

控制器：

package mypackage.foo.core.web.controller;

@RestController
@RequiredArgsConstructor
public class TaskController {

    private final TaskService taskService;

    @PostMapping("/api/task/save")
    public ResponseEntity<Task> handlePostAddTask(@RequestBody Task task) {
        Task savedTask = taskService.save(task);

        return new ResponseEntity<>(savedTask, HttpStatus.CREATED);
    }
}

{
    "name":"first task",
    "description":"some fascinating description"
}

package mypackage.foo.core.jpa.repository;

@Repository
public interface TaskDao extends JpaRepository<Task, Long> {
}

@SpringBootApplication
@EnableJpaRepositories(basePackages = {"mypackage.foo.core.jpa.repository"})
@EntityScan(basePackages = {"mypackage.foo.core.jpa.domain"})
public class FooApplication {

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

}

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

    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-devtools</artifactId>
        <scope>runtime</scope>
        <optional>true</optional>
    </dependency>
    <dependency>
        <groupId>com.h2database</groupId>
        <artifactId>h2</artifactId>
        <scope>runtime</scope>
    </dependency>
    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <scope>runtime</scope>
    </dependency>
    <dependency>
        <groupId>org.projectlombok</groupId>
        <artifactId>lombok</artifactId>
        <optional>true</optional>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-test</artifactId>
        <scope>test</scope>
    </dependency>
</dependencies>

taskservice中的save（Task Task)实质上是调用taskdao.save（Task Task)。

我也怀疑有错误的@id注释（我指的是来自错误的包），但这里不是这样。

Answer 1

Use @Data annotation from lombok as given below. This will generate both setter & getter methods. I hope this will resolve the issue. 

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;

import lombok.Data;

@Entity
@Data
public class Student {

    @Id
    @GeneratedValue
    private long id;
    private String firstName;
    private String lastName;


@Data Equivalent to @Getter @Setter @RequiredArgsConstructor @ToString @EqualsAndHashCode.

~Satheesh