AOP切面获取自定义参数注解

Java, 开发语言, 框架算法 / 作者： / / 发表评论 / AOP, ElementType, ElementType.PARAMETER, Java, PARAMETER, 切面, 自定义注解

AOP切面获取自定义参数注解：@Target(ElementType.PARAMETER)

1、创建自定义参数注解

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import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
 
@Target(ElementType.PARAMETER)
@Retention(RetentionPolicy.RUNTIME)
public @interface User {
}

这里@Target中的类型用的是PARAMETER，因为我这里的注解要用到参数中。比如：

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@GetMapping("/test")
public R myCustomProduct(@User UserVo userVo) {
return R.ok(userVo);
}

2、编写自定义注解解析器 

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import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.core.MethodParameter;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.stereotype.Component;
import org.springframework.web.bind.support.WebDataBinderFactory;
import org.springframework.web.context.request.NativeWebRequest;
import org.springframework.web.context.request.RequestAttributes;
import org.springframework.web.method.support.HandlerMethodArgumentResolver;
import org.springframework.web.method.support.ModelAndViewContainer;
 
@Component
public class UserHandlerMethodArgumentResolver implements HandlerMethodArgumentResolver {
    @Autowired
    RedisTemplate<String, Object> redisTemplate;
 
    @Override
    public boolean supportsParameter(MethodParameter methodParameter) {
       // return methodParameter.getParameterType().isAssignableFrom(UserVo.class) && methodParameter.hasParameterAnnotation(User.class);
        return methodParameter.hasParameterAnnotation(User.class);
    }
 
    @Override
    public Object resolveArgument(MethodParameter methodParameter, ModelAndViewContainer modelAndViewContainer, NativeWebRequest nativeWebRequest, WebDataBinderFactory webDataBinderFactory) throws Exception {
        //获取用户信息
        String openId = nativeWebRequest.getHeader("uuid");
        UserVo user = (UserVo) redisTemplate.opsForValue().get(RedsKeyConstant.SESSION_USER_UUID+openId);
        if(user==null||openId==null) {           
            return null;
        }
 
        return user;
    }
}

3、实现WebMvcConfigurer接口，重写addArgumentResolvers方法配置解析器

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import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.method.support.HandlerMethodArgumentResolver;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
 
import java.util.List;
 
@Configuration
public class WebMvcConfig implements WebMvcConfigurer {
    @Autowired
    private UserHandlerMethodArgumentResolver userHandlerMethodArgumentResolver;
 
    @Override
    public void addArgumentResolvers(List<HandlerMethodArgumentResolver> argumentResolvers) {
        argumentResolvers.add(userHandlerMethodArgumentResolver);
    }
}

4、创建切面

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import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.Signature;
import org.aspectj.lang.annotation.*;
import org.aspectj.lang.reflect.MethodSignature;
import org.springframework.stereotype.Component;;
import java.lang.annotation.Annotation;
import java.lang.reflect.Method;
 
@Aspect
@Component
public class LoginUserTokenAspect {
    @Around("within(com.ntan520.controller.PubController) || within(com.ntan520.controller.HomeController) ")
    public Object run(ProceedingJoinPoint joinPoint)throws Throwable{
        // System.out.println("aspect is run!!");
        Object[] args = joinPoint.getArgs();
        // 方法签名
        Signature signature1 = joinPoint.getSignature();
        // 获取的是代理类的method对象
        Method method1 = ( (MethodSignature)signature1 ).getMethod();
        // 这个方法才是目标对象上有注解的方法
        Method realMethod = joinPoint.getTarget().getClass().getDeclaredMethod(signature1.getName(), method1.getParameterTypes());
        // 取出对应的注解       
        String name = "";
        int num = -1;
        Annotation[][] parameterAnnotations = realMethod.getParameterAnnotations();
        A: for (Annotation[] annotations : parameterAnnotations) {
            for (Annotation annotation : annotations) {
                //获取注解名
                 name = annotation.annotationType().getSimpleName();
                 num = num + 1;
                 if (name.equals("User")){
                     break A;
                 }
            }
        }
 
        //获取注解
        //User user = method.getAnnotation(User.class);
        if(name.equals("User")){
            UserVo userVo = (UserVo)args[num];
            if(userVo == null || userVo.getId() == null){
                //未登录需要告诉用户你未登录
                return R.failed("401","请重新获取用户信息！");
            }else {
                //已经登录的继续处理业务
                return joinPoint.proceed(args);
            }
        } else {
            //没有这个注解的不验证登录，继续处理业务
            return joinPoint.proceed(args);
        }
    }
}
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