Question

在尝试将对象保存到H2数据库时，我不断收到此异常。

我要保留的对象定义如下：

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);
    }
}

我通过邮递员发送到该端点的有效负载：

{
    "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>

我的方法： 第一个想法是由于Id中缺少Task的setter而一直在发生，但这没有帮助。我一直想知道我是否可以找到解决此问题的任何提示？尝试调用save(task)会导致抛出IllegalStateException。

save(Task task)中的TaskService实际上是在呼叫taskDao.save(Task task)。

我也怀疑错误的@Id注解（我的意思是来自错误的软件包），但事实并非如此。

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

结果证明，删除这两行有助于：

@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，但是IntelliJ开始抱怨： Redundant declaration: @SpringBootApplication already applies given @ComponentScan

所以，我的想法是，也许这里根本不需要这些@EnableJpaRepositories和@EntityScan吗？删除它们很有帮助。我不知道为什么。

java.lang.IllegalStateException：找不到必需的标识符属性

2 个答案: