scala自学之路-29-样例类

object CaseClassDemo {

def main(args: Array[String]): Unit = {

//定义样例类

//默认带有apply方法

//构造函数的参数默认是public val修饰的

//虽然可以显示的将其改为var修饰的，但是不推荐这种方法

case class Message(sender: String, var recipient: String, body: String)

val message1 = Message("zhangsan", "lisi", "hello")

val message2 = Message("zhangsan", "lisi", "hello")

println(message1.sender)

// message1.sender=""

message1.recipient = "wangwu"

//样例类的比较，基于值或者结构比较，而不是基于引用比较

println(message1 == message2)

//样例类的copy

val message3 = message1.copy()

println("message3:" + message3.sender + "," + message3.recipient + "," + message3.body)

println(message1 == message3)

//不完全拷贝，对部分参数进行赋值

val message4 = message1.copy(sender = "zhaoliu")

println("message4:" + message4.sender + "," + message4.recipient + "," + message4.body)

}

}