Shulou(Shulou.com)05/31 Report--

This article introduces the relevant knowledge of "how to use the scala class class". In the operation of actual cases, many people will encounter such a dilemma, so let the editor lead you to learn how to deal with these situations. I hope you can read it carefully and be able to achieve something!

a. Declare classes and getter/setter methods

Class Person {/ / name is a variable. Not setting the initial value _ represents the previous name variable / / var will generate getter and setter method var name: String = _ / / age is constant, immutable / / val will only generate getter method val age = 10 / / private private variable. Private [this] val gender = "male"} can only be used inside class.

b. Constructor (primary constructor & auxiliary constructor)

Main construction method & accessory constructor

/ * 1. The main constructor is directly followed by the class name, and the parameters of the main constructor for the Chinese year are finally compiled into field 2. When the main constructor executes, it executes all statements in the class. 3. Assuming that parameters are declared without val and var, name is equivalent to private [this] and can only be called inside class! * / class Person2 (var name: String, val age: Int) {/ / primary entry-level constructor constructor println ("this is the primary constructor!") Var gender: String = _ val school: String = "ZJU" / * * 1. The name of the subsidiary constructor is this * 2. Each satellite constructor must first call the existing child constructor and subsidiary constructor * / def this (name: String, age: Int, gender: String) {this (name, age) this.gender = gender}}

c. Inherit (extends) / override parent method (override def) / override field (overrideval / override var)

However: the override var test found that the compilation failed

Class Student (name: String, age: Int, val major: String) extends Person2 (name, age) {println ("this is the subclass of Person Major is: "+ major) overrideval school: String =" Bzz "/ / methods / variables that subclasses override the parent class must use: override override def toString =" Override toString... "} object Basic2 {def main (args: Array [String]): Unit = {/ / val p = new Person / / parentheses can be omitted / p.name =" Jack "/ / println (p.name +": "+ p.age) / / val p2 = new Person2 (" Jack ") 20) / / println (p2.name + ":" + p2.age) / / val p2 = new Person2 ("Jack", 20, "male") / / println (p2.name + ":" + p2.age + ":" + p2.gender) val s = new Student ("Jack", 20, "male") / / loading order: load the parent class first Then load the subclass println (s.name + ":" + s.age + ":" + s.major + ":" + s.school)} "how to use the scala class class is introduced here, thank you for reading. If you want to know more about the industry, you can follow the website, the editor will output more high-quality practical articles for you!

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