redis 分布式计数器

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redis 分布式计数器

 

使用redis 的string类型可以实现分布式计数器

 

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使用示例：使用计数器统计对某一路径的访问次数

实现方式：创建计数器，拦截器对指定的路径拦截获取相关参数，使用计数器计数

 

  redis 计数器

@Component
public class RedisCount {

    @Autowired
    private StringRedisTemplate redisTemplate;

    public void incr(String id){
        if(redisTemplate.boundValueOps(id).get()==null){
            redisTemplate.boundValueOps(id).set("1");
        }else{
            redisTemplate.boundValueOps(id).increment();
        }
    }

    public String get(String id){
        return redisTemplate.boundValueOps(id).get();
    }
}

 

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拦截器

 

@Configuration
public class CustomInterceptor implements HandlerInterceptor {

    @Autowired
    private RedisCount redisCount;

    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        String id=request.getParameter("id");
        redisCount.incr(id);

        return true;
    }
}

 

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注册拦截器

 

@Configuration
public class WebConfig implements WebMvcConfigurer {

    @Autowired
    private CustomInterceptor interceptor;

    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(interceptor).addPathPatterns("/hello");
    }
}

 

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controller 层

 

@RestController
public class HelloController {

    @Autowired
    private StringRedisTemplate redisTemplate;

    @Autowired
    private RedisCount redisCount;

    @RequestMapping("/hello")
    public String hello(@RequestParam("id") String id){
        System.out.println("参数id为："+id);
        return id;
    }

    @RequestMapping("/get")
    public String get(String id){
        System.out.println("参数："+id+"访问次数："+ redisCount.get(id));

        return "参数："+id+"访问次数："+ redisCount.get(id);
    }

}

 

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输出示例