java - Spring AOP执行顺序

Question

我是 Spring AOP 的新手，这是我的测试代码:

目标内部com.kk.entity封装:

@Component
public class AopTargetOne {
    private String name;
    private String password;
    private String email;
    private String address;

    //getter and setters omitted
}

@Component
public class AopTargetSecond {
    private String name;
    private int age;
    private String email;
    //getter and setters omitted
}

方面:

@Component
@Aspect
public class VariableCheckAspect {

    //intercept all the setter methods
    @Pointcut("execution(* com.kk.entity.*.set*(..))")
    private void aopIsSetMethod() {

    }

    @Before("com.kk.aop.VariableCheckAspect.aopIsSetMethod() && args(val,..)")
    public void checkSetValue(JoinPoint joinpoint, String val) {
        System.err.println("******** Start check set value  with method *********** " + joinpoint.getSignature());
        System.out.println("value is:" + val);
        System.err.println("********  End ****");
    }
}

应用:

    AopTargetOne ah = context.getBean(AopTargetOne.class);
    ah.setAddress("aopholder address");
    ah.setEmail("aopholder email");
    ah.setName("aopholder name");

    AopTargetSecond ak = (AopTargetSecond) context.getBean("aopTargetSecond");
    ak.setName("aopkepper name");
    ak.setEmail("aopkepper email");
    ak.setAge(23);

我得到了输出:

******** Start check set value  with method *********** void com.kk.entity.AopTargetOne.setAddress(String)
********  End ****
value is:aopTargetOne address
******** Start check set value  with method *********** void com.kk.entity.AopTargetOne.setEmail(String)
********  End ****
******** Start check set value  with method *********** void com.kk.entity.AopTargetOne.setName(String)
********  End ****
******** Start check set value  with method *********** void com.kk.entity.AopTargetTwo.setName(String)
********  End ****
value is:aopTargetOne email
value is:aopTargetOne name
value is:aopTargetTwo name
******** Start check set value  with method *********** void com.kk.entity.AopTargetTwo.setEmail(String)
********  End ****
value is:aopTargetTwo email

这让我很困惑!看来代码没有按正常顺序运行。

虽然我期望这样的输出:

******** Start check set value  with method *********** void com.kk.entity.AopTargetOne.setAddress(String)
value is:aopTargetOne address
********  End ****
******** Start check set value  with method *********** void com.kk.entity.AopTargetOne.setEmail(String)
value is:aopTargetOne email
********  End ****
....

有什么问题吗？有办法解决这个问题吗？

Answer 1

这只是您在两个不同的输出流上执行输出的结果。您正在写入 err 和 out。 These don't necessarily get flushed in the same order (between streams).

System.err.println(..);
System.out.println(..);

写入相同的OutputStream，您将看到预期的输出。

如果我们删除包含星星的输出，我们会得到

value is:aopTargetOne address
value is:aopTargetOne email
value is:aopTargetOne name
value is:aopTargetTwo name
value is:aopTargetTwo email

这与您设置它们的顺序完全相同。