package com.qf.spark.scala

import java.sql.{Connection, DriverManager}
import java.util


/**
  * 連接池
  */
object ConnectionPoolUtil {
  /**
    * 需要設置的連接池數據
    */
  private val max = 20 //連接池連接總數
  private val connectionNum = 10 //每次產生連接數
  private val pool = new util.LinkedList[Connection]() //連接池
  private var conNum = 0 //當前連接池已經產生的連接數

  //獲取連接
  def getConnections():Connection ={
    //同步代碼塊
    AnyRef.synchronized({
      if(pool.isEmpty){
        //加載驅動
        GetConn
        for(i<- 1 to connectionNum){
          val conn = DriverManager.getConnection(
            "jdbc:mysql://localhost:3306/hadoop",
            "root",
            "123"
          )
          pool.push(conn)
          conNum += 1
        }
      }
      pool.poll()
    })
  }
  //加載驅動
  def GetConn(): Unit ={
    //控制加載
    if(conNum < max &&  pool.isEmpty){
      Class.forName("com.mysql.jdbc.Driver")
    }else if (conNum>=max && pool.isEmpty){
      println("Jdbc Pool has no connection now,please wait a moments!")
      Thread.sleep(2000)
      GetConn
    }
  }
  def returnConn(conn:Connection): Unit ={
    pool.push(conn)
  }
}

Redis連接池