How does Java limit repeated requests on the front end?-javaTutorial-php.cn

How does Java limit repeated requests on the front end?

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Release： 2023-05-14 22:58:04

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Background and purpose

The front-end page is stuck, and the user repeatedly clicks the operation button, causing the backend interface to submit multiple times in a short period of time

Implementation steps

Set aspects, Add annotations so that the interface cannot be called repeatedly within the specified time

Set an interfaceNoRepeatSubmit

import java.lang.annotation.*;
/**
 * xzj_2022_8_2
 * 重复请求限制切面
 */
@Target(ElementType.METHOD) //注解放置的目标位置,METHOD是可注解在方法级别上
@Retention(RetentionPolicy.RUNTIME) //注解在哪个阶段执行
@Documented //生成文档
public @interface NoRepeatSubmit {
    String name() default "name:";
}

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Implementation class

import java.lang.annotation.*;
/**
 * xzj_2022_8_2
 * 重复请求限制切面
 */
@Target(ElementType.METHOD) //注解放置的目标位置,METHOD是可注解在方法级别上
@Retention(RetentionPolicy.RUNTIME) //注解在哪个阶段执行
@Documented //生成文档
public @interface NoRepeatSubmit {
    String name() default "name:";
}

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Use

    @GetMapping(value = "/test")
    @NoRepeatSubmit
    public void test() {
        System.out.println("test");
        }

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Supplement: Let’s take a look at java to prevent repeated submissions on the front end

JAVA uses custom local locks to solve the problem of repeated submissions

1.Introducing jar packages

<dependency>
            <groupId>com.google.guava</groupId>
            <artifactId>guava</artifactId>
            <version>31.1-jre</version>
        </dependency>

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2. Custom local lock

package com.hzt.listener;
import java.lang.annotation.*;
/**
 * 自定义-控制重复提交锁
 */
@Target(ElementType.METHOD)     //作用于方法
@Retention(RetentionPolicy.RUNTIME)     //运行时有效
@Documented
@Inherited
public @interface LocalLock {

    String key() default "";
}

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3. Custom annotation aspect (aop interceptor implementation)

import com.google.common.cache.Cache;
import com.google.common.cache.CacheBuilder;
import org.apache.commons.lang3.StringUtils;
import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.Around;
import org.aspectj.lang.annotation.Aspect;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.context.annotation.Configuration;

import java.util.concurrent.TimeUnit;

/**
 * @Desc: 自定义注解拦截器
 * @Author: zmk
 * @Date: 2022/4/2
 */
@Aspect
@Configuration
public class LockMethodInterceptor {
    private final Logger log = LoggerFactory.getLogger(LockMethodInterceptor.class);


    private static final Cache<String, Object> CACHES = CacheBuilder.newBuilder()
            //最大缓存数
            .maximumSize(1000)
            //设置过期时间
            .expireAfterWrite(3, TimeUnit.SECONDS)
            .build();



    @Around(value = "@annotation(localLock)")
    public Object interceptor (ProceedingJoinPoint point, LocalLock localLock) {

        //localLock.key() 这个是获取controller的key属性， point.getArgs()获取key的值
        String key = getKey(localLock.key(), point.getArgs());
        if (StringUtils.isNotBlank(key)) {
            if (CACHES.getIfPresent(key) != null) {
                throw new RuntimeException("请勿重复提交");
            }
            //如果是第一次请求, 将key放入缓存
            CACHES.put(key, key);
        }

        try {
            return point.proceed();
        } catch (Throwable throwable) {
            throw new RuntimeException("服务器异常");
        } finally {
            //标记为无效
//            CACHES.invalidate(key);
        }

    }
    
    /**
     *
     * key 生成策略
     * @param key   key表达式
     * @param args  参数
     * @return  生成的key
     */
    private String getKey(String key, Object[] args) {
        for (int i = 0; i < args.length; i++) {
            key = key.replace("arg[" + i + "]", args[i].toString());
        }
        return key;
    }

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4. Define controller interface

	@GetMapping("/query")
    @LocalLock(key = "param:arg[0]")
    public String query (@RequestParam("abc") String abc) {
        return "ok";
    }

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First The result of the first call:

How does Java limit repeated requests on the front end?

The result of the second call:

How does Java limit repeated requests on the front end?

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