Springboot自定义注解，支持SPEL表达式

举例，自定义redis模糊删除注解

1.自定义注解

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

@Target(ElementType.METHOD)
@Retention(RetentionPolicy.RUNTIME)
public @interface CacheEvictFuzzy {
    /**
     * redis key集合，模糊删除
     * @return
     */
    String[] key() default "";

}

2.使用AOP拦截方法，解析注解参数

import org.apache.commons.lang3.StringUtils;
import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.AfterThrowing;
import org.aspectj.lang.annotation.Around;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Pointcut;
import org.aspectj.lang.reflect.MethodSignature;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.core.LocalVariableTableParameterNameDiscoverer;
import org.springframework.core.annotation.Order;
import org.springframework.expression.ExpressionParser;
import org.springframework.expression.spel.standard.SpelExpressionParser;
import org.springframework.expression.spel.support.StandardEvaluationContext;
import org.springframework.stereotype.Component;

import java.lang.reflect.Method;
import java.util.Set;
@Aspect
@Order(1)
@Component
public class CacheCleanFuzzyAspect {
    Logger logger = LoggerFactory.getLogger(this.getClass());

    @Autowired
    private RedisUtil redis;

    //指定要执行AOP的方法
    @Pointcut(value = "@annotation(cacheEvictFuzzy)")
    public void pointCut(CacheEvictFuzzy cacheEvictFuzzy){}


    // 设置切面为加有 @RedisCacheable注解的方法
    @Around("@annotation(cacheEvictFuzzy)")
    public Object around(ProceedingJoinPoint proceedingJoinPoint, CacheEvictFuzzy cacheEvictFuzzy){
        return doRedis(proceedingJoinPoint, cacheEvictFuzzy);
    }
    @AfterThrowing(pointcut = "@annotation(cacheEvictFuzzy)", throwing = "error")
    public void afterThrowing (Throwable  error, CacheEvictFuzzy cacheEvictFuzzy){
        logger.error(error.getMessage());
    }

    /**
     * 删除缓存
     * @param proceedingJoinPoint
     * @param cacheEvictFuzzy
     * @return
     */
    private Object doRedis (ProceedingJoinPoint proceedingJoinPoint, CacheEvictFuzzy cacheEvictFuzzy){
        Object result = null;
        //得到被切面修饰的方法的参数列表
        Object[] args = proceedingJoinPoint.getArgs();
        // 得到被代理的方法
        Method method = ((MethodSignature) proceedingJoinPoint.getSignature()).getMethod();
        String[] keys = cacheEvictFuzzy.key();
        Set<String> keySet = null;
        String realkey = "";
        for (int i = 0; i < keys.length; i++) {
            if (StringUtils.isBlank(keys[i])){
                continue;
            }
            realkey = parseKey(keys[i], method, args);
            keySet = redis.keys("*"+realkey+"*");
            if (null != keySet && keySet.size()>0){
                redis.delKeys(keySet);
                logger.debug("拦截到方法：" + proceedingJoinPoint.getSignature().getName() + "方法");
                logger.debug("删除的数据key为："+keySet.toString());
            }
        }
        try {
            result = proceedingJoinPoint.proceed();
        } catch (Throwable throwable) {
            throwable.printStackTrace();
        }finally {
            return result;
        }
    }
    /**
     * 获取缓存的key
     * key 定义在注解上，支持SPEL表达式
     * @return
     */
    private String parseKey(String key, Method method, Object [] args){

        if(StringUtils.isEmpty(key)) return null;

        //获取被拦截方法参数名列表(使用Spring支持类库)
        LocalVariableTableParameterNameDiscoverer u = new LocalVariableTableParameterNameDiscoverer();
        String[] paraNameArr = u.getParameterNames(method);

        //使用SPEL进行key的解析
        ExpressionParser parser = new SpelExpressionParser();
        //SPEL上下文
        StandardEvaluationContext context = new StandardEvaluationContext();
        //把方法参数放入SPEL上下文中
        for(int i=0;i<paraNameArr.length;i++){
            context.setVariable(paraNameArr[i], args[i]);
        }
        return parser.parseExpression(key).getValue(context,String.class);
    }
}

完事啦！

大家可以注意到关键方法就是parseKey

    /**
     * 获取缓存的key
     * key 定义在注解上，支持SPEL表达式
     * @return
     */
    private String parseKey(String key, Method method, Object [] args){

        if(StringUtils.isEmpty(key)) return null;

        //获取被拦截方法参数名列表(使用Spring支持类库)
        LocalVariableTableParameterNameDiscoverer u = new LocalVariableTableParameterNameDiscoverer();
        String[] paraNameArr = u.getParameterNames(method);

        //使用SPEL进行key的解析
        ExpressionParser parser = new SpelExpressionParser();
        //SPEL上下文
        StandardEvaluationContext context = new StandardEvaluationContext();
        //把方法参数放入SPEL上下文中
        for(int i=0;i<paraNameArr.length;i++){
            context.setVariable(paraNameArr[i], args[i]);
        }
        return parser.parseExpression(key).getValue(context,String.class);
    }

ok啦，大家记得点赞加关注啊！

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