scala中eq,==和equals的区别

• equals比较的是值是否相等

• eq比较的是 地址是否相等

• ==，如果比较的对象是null，==调用的是eq方法，如果比较的对象不是null，==调用的是equals方法

  object ObjectEqualsOps {
    def main(args: Array[String]): Unit = {
      val kp = new Worker("KP", 30)
      val kp2 = new Worker("KP", 30)
      println(kp.equals(kp2))  //true
      println(kp.eq(kp2))  //false
      println(kp == kp2)  //true
      var a = null
      var b = null
      println(a.eq(b)) //true
    }
  }
  
  class Worker {
    var name: String = _
    var age: Int = _
  
    def this(name: String, age: Int) = {
      this()
      this.name = name
      this.age = age
    }
  
    override def equals(obj: Any): Boolean = {
  
      if (obj == null) {
        return false
      }
      else if (!obj.isInstanceOf[Worker]) {
        return false
      }
      else {
        //强制转换
        var that = obj.asInstanceOf[Worker]
        this.name.equals(that.name) && this.age== that.age
      }
  
    }
  }

  

   使用模式匹配重写 equals方法

  override def equals(obj: Any): Boolean = {
  obj match {
    case that:Worker =>{
      this.name.equals(that.name) && this.age == that.age
    }
    case  _ =>{
      false
    }

  }