java redis同一时间限制同一ip登陆

Question

public void testIpInt(){  
    for(int i=0;i<=20;i++){  
        String keyName="ip";  
        String now=jedis.get(keyName);   
        if(now!=null&&Integer.parseInt(now)>10){  
            System.out.println(jedis.incr(keyName));  
            System.out.println("不给访问");  
        }else{  
            if(now==null){  
                 System.out.println("开始"+jedis.incr(keyName));  
                //秒  
                jedis.expire(keyName, 5);  
                System.out.println(jedis.dbSize());  
                }else{  
                System.out.println("计数"+jedis.incr(keyName));  
                //秒  
                jedis.expire(keyName, 5);  
                System.out.println(jedis.dbSize());  
            }  
        }  

    }  
}  

为什么实现不了？