问题描述
我在 spring-boot(v2.0.0.RELEASE)
中使用 spring-data-jpa
,我只是在MySQL上编写了一个CRUD演示,但在运行时,源代码如下:
I use spring-data-jpa
with spring-boot(v2.0.0.RELEASE)
, I just wrote a CRUD demo on MySQL, but an exception occurs during runtime, source code as follows:
源代码
User.java
@Entity
public class User implements Serializable {
private static final long serialVersionUID = 1L;
@Id
private Integer id;
private String username;
private String password;
...getter&setter
}
UserRepository.java
public interface UserRepository extends JpaRepository<User, Integer> {
}
UserServiceTest.java
@RunWith(SpringRunner.class)
@SpringBootTest
public class UserServiceTest {
@Autowired
private UserRepository userRepository;
@Test
public void getUserById() throws Exception{
userRepository.getOne(1);
}
}
application.yml
spring:
datasource:
username: ***
password: ***
driver-class-name: com.mysql.jdbc.Driver
url: ********
thymeleaf:
cache: false
jpa:
show-sql: true
hibernate:
ddl-auto: update
异常详细信息
org.hibernate.LazyInitializationException: could not initialize proxy - no Session
at org.hibernate.proxy.AbstractLazyInitializer.initialize(AbstractLazyInitializer.java:155)
at org.hibernate.proxy.AbstractLazyInitializer.getImplementation(AbstractLazyInitializer.java:268)
at org.hibernate.proxy.pojo.javassist.JavassistLazyInitializer.invoke(JavassistLazyInitializer.java:73)
at cn.shuaijunlan.sdnsecuritysystem.domain.po.User_$$_jvstc90_0.getUsername(User_$$_jvstc90_0.java)
at cn.shuaijunlan.sdnsecuritysystem.service.UserServiceTest.getUserById(UserServiceTest.java:33)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
推荐答案
您可以在测试方法中添加 @Transactional
批注以避免这种异常.
You can add @Transactional
annotation to your test method to avoid this exception.
方法 getOne
返回可以延迟加载属性的实体的引用"(代理).看到它代码-它使用 EntityManager
的 getReference
方法.从它javadoc:
Method getOne
return the 'reference' (proxy) of the entity which properties can be lazy loaded. See it code - it uses getReference
method of EntityManager
. From it javadoc:
在Spring中, EntityManager
的实现为 org.hibernate.internal.SessionImpl -因此,如果没有Session,Spring将无法获得此方法.
In Spring the implementation of EntityManager
is org.hibernate.internal.SessionImpl - so without the Session the Spring can not get this method.
要进行会话,您只需创建交易...
To have a session you can just create a transaction...
这篇关于LazyInitializationException:无法初始化代理-没有会话的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持!