这里的 jedisPool 如果不先搞成父类就无法调用 returnBrokenResource方法. 为什么,,why 类似这样的情况有无其他方法

gistfile1.txt

package com.zhisuo.redis

import redis.clients.jedis.Jedis
import redis.clients.jedis.JedisPool
import redis.clients.jedis.BinaryJedis
import redis.clients.util.Pool

/**
 * 基本redis访问
 */
class Sedis(val jedisPool: JedisPool) {

  def withJedisClient[T](body: Jedis => T): T = {
    val jedis: Jedis = jedisPool.getResource
    try {
      body(jedis)
    }catch{
    	case ex:Exception=>
    		jedisPool.asInstanceOf[Pool[Jedis]].returnBrokenResource(jedis)
    		throw ex
    }
    finally {
      jedisPool.returnResourceObject(jedis)
    }
  }
}