What is this keyword?
The keyword this can only be used inside a method and represents a reference to the current object.
Usage of this keyword
1. Access member variables, distinguish member variables and local variables
2. Access member methods
3. Access the constructor method
4. Return a reference to the current object
5. Pass the reference to the current object as a parameter to other methods
The usage is as follows: Test0505.java
class Person{
private String name;//成員變量
private int age;
Person(){}
Person(String name){//局部變量
this.name=name;//1.用"this.成員變量名稱"和重名的局部變量區(qū)分開來
}
Person(String name,int age){
this(name);
this.age=age;
}
String getInfo(){//成員方法
return "姓名：" + name + "\n年齡：" + age;
}
void print(){
System.out.println(this.getInfo());//2.用"this.成員方法名"訪問成員方法。
System.out.println(getInfo());//這種情況this關(guān)鍵字一般不寫，讓編譯器自動添加。
}
}
public class Test0505{
public static void main(String[] args){
Person p=new Person("張三",33);
p.print();
}
}class Person{
private String name;
private int age;
Person(){}
Person(String name){//不含this()的構(gòu)造方法
this.name=name;
}
Person(String name,int age){//在構(gòu)造方法內(nèi)調(diào)用另一個構(gòu)造方法
this(name);//3."this();"訪問構(gòu)造方法必須放在構(gòu)造方法的第一行
this.age=age;
}
String getInfo(){
return "姓名：" + name + "\n年齡：" + age;
}
void print(){
System.out.println(this.getInfo());
}
}
public class Test0505{
public static void main(String[] args){
Person p=new Person("張三",33);
p.print();
}
}class Leaf{
private int i=0;
Leaf increment(){
i++;
return this;//4.返回對當(dāng)前對象的引用。
}
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();
}
}class Person{
void eat(Apple apple){
Apple peeled=apple.getPeeled();
System.out.println(peeled);
}
}
class Apple{
Apple getPeeled(){
System.out.println(this);//輸出對當(dāng)前對象的引用。
return Peeler.peel(this);//5.將對當(dāng)前對象的引用作為參數(shù)傳遞給其他方法。
}
}
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: javaQuick Start
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