Introduction to the usage of this keyword in Java

Usage of this in java:

1. This generally refers to its own implicit pointer, that is, which object calls the method where this is located.

Example code: TestThis_1.java

/* Question: What is this

* Output result:

* A@4e44ac6a

*/

public class TestThis_1 {

public static void main(String[] args) {

A aa = new A();

System.out.println (aa.f()); //aa.f(), returns the reference (pointer) of the object aa

}

}

class A {

public A f() {

return this; / /Returns a reference to the class A object of the object that called the f() method

}

}

2. Distinguish variables with the same name.

Example code: TestThis_2.java

/* Common usage of this 1: Distinguish variables with the same name

* Output result:

* this. i = 1

* i = 33

*/

public class TestThis_2 {

public static void main(String[] args) {

A aa = new A(33);

}

}

class A {

public int i = 1; //This i is a member variable

/*Note: Generally not written this way, the constructor is mainly for initialization. This is mainly written for ease of understanding*/

public A(int i) { //This i is a local variable

System.out .printf("this. i = %d\n", this.i); //this.i refers to the member variable i of the object itself

System.out.printf ("i = %d\n", i); //i here is the local variable i

}

}

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