自定义注解本地缓存防止重复提交

青旅半醒 2023-02-17 02:49 17阅读 0赞

**1.引入依赖guava**

<dependency>
    	<groupId>com.google.guava</groupId>
    	<artifactId>guava</artifactId>
    	<version>21.0</version>
    </dependency>

**2.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) // 作用到方法上
    @Retention(RetentionPolicy.RUNTIME) // 运行时有效
    public @interface NoRepeatSubmit { 
    
    }

**3.缓存**

import java.util.concurrent.TimeUnit;
    
    import org.springframework.context.annotation.Bean;
    import org.springframework.context.annotation.Configuration;
    
    import com.google.common.cache.Cache;
    import com.google.common.cache.CacheBuilder;
    @Configuration
    public class UrlCache { 
    	@Bean
        public Cache<String, Integer> getCache() { 
    		// 缓存有效期为6秒
            return CacheBuilder.newBuilder().expireAfterWrite(6L, TimeUnit.SECONDS).build();
        }
    }

**4.定义AOP**  
注意：@Around非线程安全，需要synchronized 关键字

import org.apache.logging.log4j.LogManager;
    import org.apache.logging.log4j.Logger;
    import org.aspectj.lang.ProceedingJoinPoint;
    import org.aspectj.lang.annotation.Around;
    import org.aspectj.lang.annotation.Aspect;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.stereotype.Component;
    import org.springframework.web.context.request.RequestContextHolder;
    import org.springframework.web.context.request.ServletRequestAttributes;
    import org.springframework.web.servlet.ModelAndView;
    
    import com.google.common.cache.Cache;
    import com.xxx.xxx.util.Jackson2Util;
    @Aspect
    @Component
    public class NoRepeatSubmitAop { 
    	private static final Logger logger= LogManager.getLogger(NoRepeatSubmitAop.class);
    	
    	@Autowired
        private Cache<String, Integer> cache;
    	
        @Around("execution(* com.xxx.xxx..*Controller.*(..)) && @annotation(nrs)")
        public synchronized Object around(ProceedingJoinPoint pjp, NoRepeatSubmit nrs) { 
        	
        	try { 
    			ServletRequestAttributes attributes = (ServletRequestAttributes) RequestContextHolder.getRequestAttributes();
                String sessionId = RequestContextHolder.getRequestAttributes().getSessionId();
                HttpServletRequest request = attributes.getRequest();
                String key = sessionId + "-" + request.getServletPath();
             // 如果缓存中有这个url视为重复提交
                if (cache.getIfPresent(key) == null) { 
                    Object o = pjp.proceed();
                    cache.put(key, 1);
                    return o;
                } else { 
                    logger.info("重复提交");
                    ModelAndView mv = new ModelAndView();
            		mv.setView(Jackson2Util.jsonView());
            		mv.addObject("code", 1);
            		mv.addObject("msg", "请不要重复提交!");
                    return mv;
                }
            } catch (Throwable e) { 
                e.printStackTrace();
                logger.error("验证重复提交时出现未知异常!");
                ModelAndView mv = new ModelAndView();
        		mv.setView(Jackson2Util.jsonView());
        		mv.addObject("code", 2);
        		mv.addObject("msg", "验证重复提交内部错误!");
                return mv;
            }
        }
    }

**4.Controller方法使用**

@NoRepeatSubmit
    	@RequestMapping("uploadData")
    	public ModelAndView uploadData(UploadData data) throws Exception { 
    		ModelAndView mv = new ModelAndView();
    		mv.setView(Jackson2Util.jsonView());
    				mv.addObject("code","0");
    				mv.addObject("msg","上传成功");
    				return mv;
    }