Spring aop doesn't run when project starts

Question

I'v implemented a spring-boot aop demo and it runs well, but when I want to use it to load some resource when the project starts, it doesn't work somehow

Aop:

package com.neo.mysql;

import org.aspectj.lang.JoinPoint;
import org.aspectj.lang.annotation.After;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Before;
import org.aspectj.lang.reflect.MethodSignature;
import org.springframework.stereotype.Component;

import java.lang.reflect.Method;

/**
 * Created by li_weia on 2017/7/6.
 */
@Aspect
@Component
public class DynamicDataSourceAspect {

    @Before("@annotation(VendorSource)")
    public void beforeSwitchDS(JoinPoint point){

        //获得当前访问的class
        Class<?> className = point.getTarget().getClass();

        //获得访问的方法名
        String methodName = point.getSignature().getName();
        //得到方法的参数的类型
        Class[] argClass = ((MethodSignature)point.getSignature()).getParameterTypes();
        String dataSource = DataSourceContextHolder.DEFAULT_DS;
        try {
            // 得到访问的方法对象
            Method method = className.getMethod(methodName, argClass);

            // 判断是否存在@DS注解
            if (method.isAnnotationPresent(VendorSource.class)) {
                VendorSource annotation = method.getAnnotation(VendorSource.class);
                // 取出注解中的数据源名
                dataSource = annotation.value();
            }
        } catch (Exception e) {
            e.printStackTrace();
        }

        // 切换数据源
        DataSourceContextHolder.setDB(dataSource);

    }


    @After("@annotation(VendorSource)")
    public void afterSwitchDS(JoinPoint point){

        DataSourceContextHolder.clearDB();

    }
}

The VendorSource annotation:

package com.neo.mysql;

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

/**
 * Created by li_weia on 2017/7/6.
 */
@Target({ ElementType.METHOD, ElementType.TYPE })
@Retention(RetentionPolicy.RUNTIME)
public @interface VendorSource {
    String value() default "vendor-master";
}

It runs well here, I can successfully change datasource by annotation:

package com.neo.web;

import com.neo.entity.SiteEntity;
import com.neo.mapper.ClassMappingDao;
import com.neo.mysql.VendorSource;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import java.util.List;

@RestController
public class UserController {

    private final ClassMappingDao siteMapper;

    @Autowired(required = false)
    public UserController(ClassMappingDao siteMapper) {
        this.siteMapper = siteMapper;
    }

    @RequestMapping("/getSites")
    @VendorSource("vendor-read")
    public List<SiteEntity> getUsers() {
        return siteMapper.getAllSite();
    }
}

but it doesn't work here, the aop method is not invoked at all:

package com.neo.component;

import com.neo.entity.SiteEntity;
import com.neo.mapper.ClassMappingDao;
import com.neo.mysql.VendorSource;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;

import java.util.List;

/**
 * Created by li_weia on 2017/7/7.
 */
@Component
public class TestComponent{
    private final ClassMappingDao userMapper;

    @Autowired(required = false)
    public TestComponent(ClassMappingDao userMapper) {
        this.userMapper = userMapper;
        init();
    }

    @VendorSource("vendor-read")
    public void init() {
        List<SiteEntity> sites = userMapper.getAllSite();
        for(SiteEntity site: sites){
            System.out.println(site.getSite());
        }
    }
}

Answer 1

You need to fully qualify the annotation, like so:

@Before("execution(public * *(..)) && @annotation(com.neo.mysql.VendorSource)")
private void whatever() {}

Also, as mentioned in my comment above, you need to have spring-boot-starter-aop on classpath. Maybe you already do, but since you didn't say, it's worth mentioning.

Edit:

I didn't notice the real problem before, I wasn't paying attention.

1. Spring AOP only triggers if you make calls from another class. This is because Spring needs to be able to intercept the call and run the pointcut. Calling the method from constructor is not going to do anything.

2. You can do a hackish workaround. Create a @PostConstruct void postConstruct() {} method in your class (not constructor), autowire ApplicationContext, and then do MyClassWithInitMethod myClass = context.getBean(MyClassWithInitMethod.class) in the postConstruct method. Then call the method on myClass, and AOP will kick in.

Frankly, I didn't previously check what you are doing in your pointcut, and it's a terrible idea. When multiple threads run, they are going to overwrite the static context, and create a race-condition that you'll then create another question for. Don't do it! Use the factory pattern instead, and inject the DataSourceFactory in the classes that now have the annotation.