What is this?
This is an object of its own, representing the object itself, and can be understood as: a pointer to the object itself.
Usage is as follows:
Use "this. member variable name" to distinguish it from local variables with the same name;
Use "this. member method name" to access member methods.
class Person{ private String name;//成员变量 private int age; Person(){} Person(String name){//局部变量 this.name=name;//1.用"this.成员变量名称"和重名的局部变量区分开来 } Person(String name,int age){ this(name); this.age=age; } String getInfo(){//成员方法 return "姓名：" + name + "\n年龄：" + age; } void print(){ System.out.println(this.getInfo());//2.用"this.成员方法名"访问成员方法。 System.out.println(getInfo());//这种情况this关键字一般不写，让编译器自动添加。 } } public class Test0505{ public static void main(String[] args){ Person p=new Person("张三",33); p.print(); } }
This() access constructor must be placed in the first line of the constructor
class Person{ private String name; private int age; Person(){} Person(String name){//不含this()的构造方法 this.name=name; } Person(String name,int age){//在构造方法内调用另一个构造方法 this(name);//3."this();"访问构造方法必须放在构造方法的第一行 this.age=age; } String getInfo(){ return "姓名：" + name + "\n年龄：" + age; } void print(){ System.out.println(this.getInfo()); } } public class Test0505{ public static void main(String[] args){ Person p=new Person("张三",33); p.print(); } }
Return to the current Reference to the object
class Leaf{ private int i=0; Leaf increment(){ i++; return this;//4.返回对当前对象的引用。 } void print(){ System.out.println("i="+i); } } public class Test0505{ public static void main(String[] args){ Leaf x=new Leaf(); x.increment().increment().increment().print(); } }
Pass a reference to the current object as a parameter to other methods
class Person{ void eat(Apple apple){ Apple peeled=apple.getPeeled(); System.out.println(peeled); } } class Apple{ Apple getPeeled(){ System.out.println(this);//输出对当前对象的引用。 return Peeler.peel(this);//5.将对当前对象的引用作为参数传递给其他方法。 } } class Peeler{ static Apple peel(Apple apple){ return apple; } } public class Test0505{ public static void main(String[] args){ Apple a=new Apple(); System.out.println(a); new Person().eat(a); } }
Recommended tutorial:Java Tutorial
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