内容简介:根据异常信息,猜测是注入根据异常信息可知,Spring的IoC容器中并没有在
开发环境
JDK 1.8 Springboot 2.1.1.RELEASE
pom配置
<parent> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-parent</artifactId> <version>2.1.1.RELEASE</version> <relativePath/> <!-- lookup parent from repository --> </parent> <dependencies> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-data-jpa</artifactId> </dependency> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> <version>8.0.13</version> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-test</artifactId> <scope>test</scope> </dependency> </dependencies>
关键代码
实体类
@Entity public class User implements Serializable { @Id @GeneratedValue(strategy = GenerationType.IDENTITY) private Integer id; private String name; public Integer getId() { return id; } public void setId(Integer id) { this.id = id; } public String getName() { return name; } public void setName(String name) { this.name = name; } }
Repository
public interface UserRepository extends JpaRepository<User,Integer> { }
自定义服务
@Service public class MyService { public void print(){ System.out.println(this.getClass().getSimpleName()+" call"); } }
拦截器
public class SimpleInterceptor extends EmptyInterceptor { @Resource private MyService myService; @Override public String onPrepareStatement(String sql) { myService.print(); System.out.println("sql:"+sql); return super.onPrepareStatement(sql); } }
启动类
@SpringBootApplication public class BootHibernateInterceptorProblemApplication { public static void main(String[] args) { SpringApplication.run(BootHibernateInterceptorProblemApplication.class, args); } }
配置
## DataSource spring.datasource.url=jdbc:mysql://localhost:3306/demo?characterEncoding=utf8&useSSL=true spring.datasource.username=root spring.datasource.password=123456789 ## hibernate spring.jpa.hibernate.ddl-auto=update ## add interceptor spring.jpa.properties.hibernate.ejb.interceptor=com.rjh.interceptor.SimpleInterceptor
单元测试类
@RunWith(SpringRunner.class) @SpringBootTest public class BootHibernateInterceptorProblemApplicationTests { @Resource private UserRepository userRepository; @Test public void contextLoads() { System.out.println(userRepository.findAll()); } }
运行结果
java.lang.NullPointerException at com.rjh.interceptor.SimpleInterceptor.onPrepareStatement(SimpleInterceptor.java:20) ... ... ...
分析
根据异常信息,猜测是注入 MyService
失败
修改单元测试
@RunWith(SpringRunner.class) @SpringBootTest public class BootHibernateInterceptorProblemApplicationTests { @Resource private UserRepository userRepository; @Resource private MyService myService; @Resource private SimpleInterceptor simpleInterceptor; @Test public void contextLoads() { Assert.assertNotNull(myService); Assert.assertNotNull(simpleInterceptor); System.out.println(userRepository.findAll()); } }
运行结果
Caused by: org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type 'com.rjh.interceptor.SimpleInterceptor' available: expected at least 1 bean which qualifies as autowire candidate. Dependency annotations: {@javax.annotation.Resource(shareable=true, lookup=, name=, description=, authenticationType=CONTAINER, type=class java.lang.Object, mappedName=)} ...
分析
根据异常信息可知,Spring的IoC容器中并没有 SimpleInterceptor
这个 Bean
,从此处可知 spring.jpa.properties.hibernate.ejb.interceptor=com.rjh.interceptor.SimpleInterceptor
并没有把这个拦截器注册到Spring容器中
失败方案
在 SimpleInterceptor
上添加 @Component
注解,将 SimpleInterceptor
注册到Spring容器中。同时注释 spring.jpa.properties.hibernate.ejb.interceptor
配置
失败: SimpleInterceptor
的构造方法触发了两次,添加到 Hibernate
中的 SimpleInterceptor
实例和注册到Spring容器中的 SimpleInterceptor
实例并不是同一个实例
解决方法
增加一个获取Spring的 ApplicationContext
实例的 工具 类,通过这个工具类调用需要注入的服务的方法
工具类
@Component public class SpringContextUtil implements ApplicationContextAware { private static ApplicationContext applicationContext; @Override public void setApplicationContext(ApplicationContext applicationContext) throws BeansException { SpringContextUtil.applicationContext=applicationContext; } public static ApplicationContext getApplicationContext() { return applicationContext; } }
修改拦截器
public class SimpleInterceptor extends EmptyInterceptor { @Override public String onPrepareStatement(String sql) { MyService myService= SpringContextUtil.getApplicationContext().getBean(MyService.class); myService.print(); System.out.println("sql:"+sql); return super.onPrepareStatement(sql); } }
执行结果
MyService call sql:select user0_.id as id1_0_, user0_.name as name2_0_ from user user0_ []
以上所述就是小编给大家介绍的《Springboot整合Hibernate拦截器时无法向拦截器注入Bean》,希望对大家有所帮助,如果大家有任何疑问请给我留言,小编会及时回复大家的。在此也非常感谢大家对 码农网 的支持!
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