java - JUnit hibernate.LazyInitializationException

Question

我有一对多双向的简单示例。

@JsonIgnoreProperties({"hibernateLazyInitializer", "handler"})
@Data
@Entity
public class Post {
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Long id;
    private String title;
    private String description;
    private Date createDate;
    private int rate;

    @ToString.Exclude
    @OneToMany(mappedBy = "post",cascade = CascadeType.ALL)
    List<Comment> comments=new ArrayList<>();
}

.

@JsonIgnoreProperties({"hibernateLazyInitializer", "handler"})
@Data
@Entity
public class Comment {
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Long id;
    private String text;

    @JsonIgnore
    @ManyToOne
    private Post post;

}

当我打电话时

@GetMapping("post/{id}")
public Post getPost(@PathVariable Long id) {
    return postRepository.getOne(id);
}

一切都好但是当我做@Test时

@Test
void getPost() {
    Post post = postRepository.getOne(1L);
    System.out.println(post);
}

我有错误

org.hibernate.LazyInitializationException: could not initialize proxy [ge.cse.jpademo.model.Post#1] - no Session

我该如何解决这个问题？

我尝试添加 @Transactional 注释及其工作原理。

@Transactional
@Test
void getPost() {
    Post post = postRepository.getOne(1L);
    System.out.println(post);
}

.

Post(id=1, title=სატესტო პოსტი3, description=სატესტო კონტენტი, createDate=2020-05-19 02:26:16.237, rate=5)

但是为什么我必须在 @Test 调用中添加 @Transactional 以及为什么它在没有 @Transactional 的 Controller 中工作？

Answer 1

But why i must add @Transactional in @Test call and why its works in controller without @Transactional ?

Open Session in View (OSIV) 在 Spring Boot 应用程序中默认启用，这可以解释为什么您的生产代码在使用的方法上不需要 @Transactional 注解延迟初始化的实体。然而，启用 OSIV 也有其缺点，被认为是 anti-pattern .