java秒殺之redis限流操作詳解

Posted on 2021-11-25 by WalkonNet

最近寫到瞭一個秒殺的功能模塊，為瞭保證高並發情況下不會宕機，要從多方面去考慮，當前的限流操作隻是其中的一個方面，具體操作如下。

導入所需依賴

<properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <maven.compiler.source>1.8</maven.compiler.source>
    <maven.compiler.target>1.8</maven.compiler.target>
    <spring.version>5.0.2.RELEASE</spring.version>
    <slf4j.version>1.6.6</slf4j.version>
    <log4j.version>1.2.12</log4j.version>
    <mysql.version>5.1.6</mysql.version>
    <mybatis.version>3.4.5</mybatis.version>
  </properties>

  <dependencies>

    <dependency>
      <groupId>org.aspectj</groupId>
      <artifactId>aspectjweaver</artifactId>
      <version>1.6.8</version>
    </dependency>

    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-aop</artifactId>
      <version>${spring.version}</version>
    </dependency>

    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-context</artifactId>
      <version>${spring.version}</version>
    </dependency>

    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-web</artifactId>
      <version>${spring.version}</version>
    </dependency>

    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-webmvc</artifactId>
      <version>${spring.version}</version>
    </dependency>

    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-test</artifactId>
      <version>${spring.version}</version>
    </dependency>

    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-tx</artifactId>
      <version>${spring.version}</version>
    </dependency>

    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-jdbc</artifactId>
      <version>${spring.version}</version>
    </dependency>

    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>4.12</version>
      <scope>compile</scope>
    </dependency>

    <dependency>
      <groupId>mysql</groupId>
      <artifactId>mysql-connector-java</artifactId>
      <version>${mysql.version}</version>
    </dependency>

    <dependency>
      <groupId>javax.servlet</groupId>
      <artifactId>servlet-api</artifactId>
      <version>2.5</version>
      <scope>provided</scope>
    </dependency>

    <dependency>
      <groupId>javax.servlet.jsp</groupId>
      <artifactId>jsp-api</artifactId>
      <version>2.0</version>
      <scope>provided</scope>
    </dependency>

    <dependency>
      <groupId>jstl</groupId>
      <artifactId>jstl</artifactId>
      <version>1.2</version>
    </dependency>

    <!-- log start -->
    <dependency>
      <groupId>log4j</groupId>
      <artifactId>log4j</artifactId>
      <version>${log4j.version}</version>
    </dependency>

    <dependency>
      <groupId>org.slf4j</groupId>
      <artifactId>slf4j-api</artifactId>
      <version>${slf4j.version}</version>
    </dependency>

    <dependency>
      <groupId>org.slf4j</groupId>
      <artifactId>slf4j-log4j12</artifactId>
      <version>${slf4j.version}</version>
    </dependency>

    <!-- log end -->
    <dependency>
      <groupId>org.mybatis</groupId>
      <artifactId>mybatis</artifactId>
      <version>${mybatis.version}</version>
    </dependency>

    <dependency>
      <groupId>org.mybatis</groupId>
      <artifactId>mybatis-spring</artifactId>
      <version>1.3.0</version>
    </dependency>

    <dependency>
      <groupId>c3p0</groupId>
      <artifactId>c3p0</artifactId>
      <version>0.9.1.2</version>
      <type>jar</type>
      <scope>compile</scope>
    </dependency>

    <dependency>
      <groupId>org.springframework.data</groupId>
      <artifactId>spring-data-redis</artifactId>
      <version>1.7.2.RELEASE</version>
    </dependency>

    <dependency>
      <groupId>redis.clients</groupId>
      <artifactId>jedis</artifactId>
      <version>2.8.1</version>
    </dependency>
</dependencies>

編寫註解

@Retention(RUNTIME)//運行時有效
@Target(ElementType.METHOD)//用在方法上
 public @interface AccessLimit {
     int seconds();//時間范圍(單位:秒)
     int maxCount();//在這個時間范圍內最大訪問次數
 }

編寫攔截器

public class AcessLimiitInterceptor implements HandlerInterceptor {
 //註入redisTemplate
    @Autowired
    private RedisTemplate<String,String> redisTemplate;


    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) {
     //設置redisTemplate的序列化方式(必須設置為這種方式，因為要用到incr)
        redisTemplate.setKeySerializer(new StringRedisSerializer());
        redisTemplate.setValueSerializer(new StringRedisSerializer());
       
        if(handler instanceof HandlerMethod){
         //查看該方法上是否有@AcessLimit註解
            HandlerMethod hm= (HandlerMethod) handler;
            AccessLimit accessLimit=hm.getMethodAnnotation(AccessLimit.class);
            //沒有@AcessLimit註解，證明無限流操作，直接放行
            if(accessLimit==null){
                return true;
            }
             //獲取註解的參數值
            int seconds=accessLimit.seconds();//時間范圍
            int maxCount=accessLimit.maxCount();//時間范圍內的最大訪問次數
            //該請求的路徑
            String key=request.getRequestURI();
            //在該時間范圍內已經訪問的次數
            String countStr=redisTemplate.opsForValue().get(key);
            Integer count=null;
            //如果不是第一次訪問，則把訪問次數轉換為integer類型
            if(countStr!=null){
                count= Integer.valueOf(redisTemplate.opsForValue().get(key));
            }
   //拿到訪問次數的過期時間
            Long keySeconds=redisTemplate.getExpire(key);
            //該時間范圍內沒有訪問
            if(count==null){
             //第一次訪問，設置key為訪問路徑，值為訪問次數1
                redisTemplate.opsForValue().set(key,1+"");
                //設置過期時間
                redisTemplate.expire(key,600, TimeUnit.SECONDS);
            }else if(count<maxCount){//在該時間范圍內已經有訪問記錄，但訪問沒有達到最大次數
             //訪問次數+1
                redisTemplate.opsForValue().increment(key,1);
                //設置剩餘過期時間(修改完該key的value值後，對應的過期時間會失效，需重新設置)
                redisTemplate.expire(key,keySeconds, TimeUnit.SECONDS);
            }else{//在該時間范圍內已經超過最大的訪問次數
                return false;
            }
        }
        //放行
        return true;
    }
}

編寫application.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:aop="http://www.springframework.org/schema/aop"
       xmlns:tx="http://www.springframework.org/schema/tx"
       xmlns:p="http://www.springframework.org/schema/p"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
 http://www.springframework.org/schema/beans/spring-beans.xsd
 http://www.springframework.org/schema/context
 http://www.springframework.org/schema/context/spring-context.xsd
 http://www.springframework.org/schema/aop
 http://www.springframework.org/schema/aop/spring-aop.xsd
 http://www.springframework.org/schema/tx
 http://www.springframework.org/schema/tx/spring-tx.xsd">

    <!--開啟註解的掃描，希望處理service和dao，controller不需要Spring框架去處理-->
    <context:component-scan base-package="cn.itcast" >
        <!--配置哪些註解不掃描-->
        <context:exclude-filter type="annotation" expression="org.springframework.stereotype.Controller" />
    </context:component-scan>
    <!--Spring整合MyBatis框架-->
    <!--配置連接池-->
    <bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
        <property name="driverClass" value="com.mysql.jdbc.Driver"/>
        <property name="jdbcUrl" value="jdbc:mysql:///ssm"/>
        <property name="user" value="root"/>
        <property name="password" value="root"/>
    </bean>

    <!--配置SqlSessionFactory工廠-->
    <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
        <property name="dataSource" ref="dataSource" />
    </bean>

    <!--配置AccountDao接口所在包-->
    <bean id="mapperScanner" class="org.mybatis.spring.mapper.MapperScannerConfigurer">
        <property name="basePackage" value="cn.itcast.dao"/>
    </bean>

    <!--配置Spring框架聲明式事務管理-->
    <!--配置事務管理器-->
    <bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
        <property name="dataSource" ref="dataSource" />
    </bean>

    <!--配置事務通知-->
    <tx:advice id="txAdvice" transaction-manager="transactionManager">
        <tx:attributes>
            <tx:method name="find*" read-only="true"/>
            <tx:method name="*" isolation="DEFAULT"/>
        </tx:attributes>
    </tx:advice>

    <!--配置AOP增強-->
    <aop:config>
        <aop:advisor advice-ref="txAdvice" pointcut="execution(* cn.itcast.service.impl.*ServiceImpl.*(..))"/>
    </aop:config>


    <context:property-placeholder location="classpath*:*.properties"></context:property-placeholder>
    <!-- <context:property-placeholder location="classpath*:properties/*.properties" />   -->

    <!-- redis 相關配置 -->
    <bean id="poolConfig" class="redis.clients.jedis.JedisPoolConfig">
        <property name="maxIdle" value="${redis.maxIdle}" />
        <property name="maxWaitMillis" value="${redis.maxWait}" />
        <property name="testOnBorrow" value="${redis.testOnBorrow}" />
    </bean>
    
    <bean id="JedisConnectionFactory" class="org.springframework.data.redis.connection.jedis.JedisConnectionFactory"
          p:host-name="${redis.host}" p:port="${redis.port}" p:password="${redis.pass}" p:pool-config-ref="poolConfig"/>

    <bean id="redisTemplate" class="org.springframework.data.redis.core.RedisTemplate">
        <property name="connectionFactory" ref="JedisConnectionFactory" />
    </bean>
    
</beans>

配置web.xml

<web-app>
  <display-name>Archetype Created Web Application</display-name>

  <!--配置Spring的監聽器，默認隻加載WEB-INF目錄下的applicationContext.xml配置文件-->
  <listener>
    <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
  </listener>
  <!--設置配置文件的路徑-->
  <context-param>
    <param-name>contextConfigLocation</param-name>
    <param-value>classpath:applicationContext.xml</param-value>
  </context-param>

  <!--配置前端控制器-->
  <servlet>
    <servlet-name>dispatcherServlet</servlet-name>
    <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
    <!--加載springmvc.xml配置文件-->
    <init-param>
      <param-name>contextConfigLocation</param-name>
      <param-value>classpath:springmvc.xml</param-value>
    </init-param>
    <!--啟動服務器，創建該servlet-->
    <load-on-startup>1</load-on-startup>
  </servlet>
  <servlet-mapping>
    <servlet-name>dispatcherServlet</servlet-name>
    <url-pattern>/</url-pattern>
  </servlet-mapping>

  <!--解決中文亂碼的過濾器-->
  <filter>
    <filter-name>characterEncodingFilter</filter-name>
    <filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
    <init-param>
      <param-name>encoding</param-name>
      <param-value>UTF-8</param-value>
    </init-param>
  </filter>
  <filter-mapping>
    <filter-name>characterEncodingFilter</filter-name>
    <url-pattern>/*</url-pattern>
  </filter-mapping>
  
</web-app>

註解應用

@AccessLimit(seconds = 500,maxCount = 3)
    @RequestMapping(value = "/findAll")
    public String findAll(Model model){
        System.out.println("csl");
        return "list";
    }

總結

以上操作就完成瞭java後臺使用redisTemplate的限流操作，這裡還需各位自己開啟一個redis服務端並且把配置文件中的地址改成對應的ip，希望以上內容對大傢有幫助，多提寶貴意見。

以上就是本文的全部內容，希望對大傢的學習有所幫助，也希望大傢多多支持WalkonNet。

java秒殺之redis限流操作詳解

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