我使用 spring-boot(v2.0.0.RELEASE)
和 spring-data-jpa
,在MySQL上编写了一个CRUD演示程序。然而,在运行时出现了异常。以下是源代码:
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
异常细节
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)
我尝试了另一种方法 userRepository.findOne(1)
,它可以成功运行。
@Transactional
,它可以成功运行,你能否提供更多关于为什么它可以无异常运行的细节? - Shuai Junlan