java.lang.IllegalStateException：未找到必需的标识符属性

Question

我在尝试将对象保存到 H2 数据库时不断收到此异常。

我要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);
    }
}

我通过 Postman 发送到该端点的负载：

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

存储库：

package mypackage.foo.core.jpa.repository;

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

应用配置：

@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);
    }

}

Maven 部门：

<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>

我的做法： 第一个想法是，由于 Task 中的 Id 缺少 setter，所以它一直在发生，但它没有帮助。我一直想知道是否可以得到任何提示来解决这个问题？任何调用 save(task) 的尝试都会导致抛出 IllegalStateException。

TaskService中的save(Task task)本质上是在调用taskDao.save(Task task).

我也怀疑是错误的 @Id 注释（我的意思是来自错误的包），但这里不是这种情况。

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

Answer 2

原来删除这两行有帮助：

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

当我在切换到 MySql 后注意到相同的体验时，我开始认为问题一定出在我的配置上。我试图用 ComponentScan 替换这些注释，但 IntelliJ 开始抱怨： Redundant declaration: @SpringBootApplication already applies given @ComponentScan

所以，我的想法是，也许这些 @EnableJpaRepositories 和 @EntityScan 在这里根本没有必要？删除它们有帮助。我不确定为什么。

java.lang.IllegalStateException：未找到必需的标识符属性

java.lang.IllegalStateException: Required identifier property not found

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java.lang.IllegalStateException：未找到必需的标识符 属性

java.lang.IllegalStateException: Required identifier property not found

java

spring

hibernate

spring-boot

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java.lang.IllegalStateException：未找到必需的标识符属性