摘要：同時(shí)注釋配置失敗的構(gòu)造方法觸發(fā)了兩次，添加到中的實(shí)例和注冊到容器中的實(shí)例并不是同一個(gè)實(shí)例解決方法增加一個(gè)獲取的實(shí)例的工具類，通過這個(gè)工具類調(diào)用需要注入的服務(wù)的方法工具類修改攔截器執(zhí)行結(jié)果

JDK 1.8

Springboot 2.1.1.RELEASE

    
        org.springframework.boot
        spring-boot-starter-parent
        2.1.1.RELEASE
         
    
    
    
        
            org.springframework.boot
            spring-boot-starter-data-jpa
        

        
            mysql
            mysql-connector-java
            8.0.13
        

        
            org.springframework.boot
            spring-boot-starter-test
            test
        
    

@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;
    }
}

public interface UserRepository extends JpaRepository {

}

@Service
public class MyService {

    public void print(){
        System.out.println(this.getClass().getSimpleName()+" call");
    }
}

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);
    }
}

@SpringBootApplication
public class BootHibernateInterceptorProblemApplication {

    public static void main(String[] args) {
        SpringApplication.run(BootHibernateInterceptorProblemApplication.class, args);
    }

}

## 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

@RunWith(SpringRunner.class)
@SpringBootTest
public class BootHibernateInterceptorProblemApplicationTests {

    @Resource
    private UserRepository userRepository;

    @Test
    public void contextLoads() {
        System.out.println(userRepository.findAll());
    }

}

java.lang.NullPointerException
    at com.rjh.interceptor.SimpleInterceptor.onPrepareStatement(SimpleInterceptor.java:20)
    ...
    ...
    ...

根據(jù)異常信息，猜測是注入MyService失敗

@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());
    }

}

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=)}
    ...

根據(jù)異常信息可知，Spring的IoC容器中并沒有SimpleInterceptor這個(gè)Bean，從此處可知spring.jpa.properties.hibernate.ejb.interceptor=com.rjh.interceptor.SimpleInterceptor并沒有把這個(gè)攔截器注冊到Spring容器中

在SimpleInterceptor上添加@Component注解，將SimpleInterceptor注冊到Spring容器中。同時(shí)注釋spring.jpa.properties.hibernate.ejb.interceptor配置

失敗：SimpleInterceptor的構(gòu)造方法觸發(fā)了兩次，添加到Hibernate中的SimpleInterceptor實(shí)例和注冊到Spring容器中的SimpleInterceptor實(shí)例并不是同一個(gè)實(shí)例

增加一個(gè)獲取Spring的ApplicationContext實(shí)例的工具類，通過這個(gè)工具類調(diào)用需要注入的服務(wù)的方法

@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;
    }
}

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);
    }

}

MyService call
sql:select user0_.id as id1_0_, user0_.name as name2_0_ from user user0_
[]