java 注解示例（springboot自定义注解为对象赋值）

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java 注解示例

 

springboot中，可利用 aop 为对象实例赋值

 

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示例

 

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annotation 层：自定义annotation

 

@Retention(RetentionPolicy.RUNTIME)
public @interface CustomAnnotation {

    String value() default "";
}

 

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pojo 层：使用的类

 

@Component
public class Person {

    private String name;
    private Integer age;

    @CustomAnnotation("瓜田李下")
    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    @CustomAnnotation("24")
    public Integer getAge() {
        return age;
    }

    public void setAge(Integer age) {
        this.age = age;
    }

    @Override
    public String toString() {
        return this.name+"  "+this.age;
    }
}

 

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aop 层：定义切面

 

@Aspect
@Component
public class CustomAspect {

    @Pointcut("@annotation(com.example.demo.annotation.CustomAnnotation)")
    public void fun(){

    }

    @Before("fun()")
    public void before(JoinPoint joinPoint){
        Person person=(Person) joinPoint.getTarget();

        MethodSignature methodSignature=(MethodSignature) joinPoint.getSignature();
        Method method=methodSignature.getMethod();
        CustomAnnotation customAnnotation=method.getAnnotation(CustomAnnotation.class);
        if (method.getName().equals("getName")){
            if (person.getName()==null){
                person.setName(customAnnotation.value());
            }
        }else {
            if (person.getAge()==null){
                person.setAge(Integer.parseInt(customAnnotation.value().toString()));
            }
        }
    }
}

 

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controller 层

 

@RestController
public class HelloController {

    @Autowired
    private Person person;

    @RequestMapping("/hello")
    public void hello(){

        System.out.println(person.getName()+"  "+person.getAge());
    }
}

 

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控制台输出

 

2019-11-16 10:26:16.116  INFO 23704 --- [nio-8080-exec-1] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring DispatcherServlet 'dispatcherServlet'
2019-11-16 10:26:16.116  INFO 23704 --- [nio-8080-exec-1] o.s.web.servlet.DispatcherServlet        : Initializing Servlet 'dispatcherServlet'
2019-11-16 10:26:16.124  INFO 23704 --- [nio-8080-exec-1] o.s.web.servlet.DispatcherServlet        : Completed initialization in 8 ms
瓜田李下  24