Java中的“this”引用-yiteyi-C++库

“this”是一个引用当前对象的引用变量。

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以下是在java中使用“this”关键字的方法： 1.使用“this”关键字引用当前类实例变量

JAVA

                         //Java code for using 'this' keyword to                       
                         //refer current class instance variables                       
                         class                                     Test                       
                         {                       
                                                 int                                     a;                       
                                                 int                                     b;                       
                                   
                                                 // Parameterized constructor                       
                                                 Test(                                     int                                     a,                                     int                                     b)                       
                                                 {                       
                                                 this                                     .a = a;                       
                                                 this                                     .b = b;                       
                                                 }                       
           
                                                 void                                     display()                       
                                                 {                       
                                                 //Displaying value of variables a and b                       
                                                 System.out.println(                                     "a = "                                     + a +                                     "  b = "                                     + b);                       
                                                 }                       
           
                                                 public                                     static                                     void                                     main(String[] args)                       
                                                 {                       
                                                 Test object =                                     new                                     Test(                                     10                                     ,                                     20                                     );                       
                                                 object.display();                       
                                                 }                       
                         }                       

输出：

a = 10  b = 20

2.使用this（）调用当前类构造函数

JAVA

                         // Java code for using this() to                       
                         // invoke current class constructor                       
                         class                                     Test                       
                         {                       
                                                 int                                     a;                       
                                                 int                                     b;                       
           
                                                 //Default constructor                       
                                                 Test()                       
                                                 {                       
                                                 this                                     (                                     10                                     ,                                     20                                     );                       
                                                 System.out.println(                                     "Inside  default constructor "                                     );                       
                                                 }                       
                                   
                                                 //Parameterized constructor                       
                                                 Test(                                     int                                     a,                                     int                                     b)                       
                                                 {                       
                                                 this                                     .a = a;                       
                                                 this                                     .b = b;                       
                                                 System.out.println(                                     "Inside parameterized constructor"                                     );                       
                                                 }                       
           
                                                 public                                     static                                     void                                     main(String[] args)                       
                                                 {                       
                                                 Test object =                                     new                                     Test();                       
                                                 }                       
                         }                       

输出：

Inside parameterized constructorInside  default constructor

3.使用“this”关键字返回当前类实例

JAVA

                         //Java code for using 'this' keyword                       
                         //to return the current class instance                       
                         class                                     Test                       
                         {                       
                                                 int                                     a;                       
                                                 int                                     b;                       
           
                                                 //Default constructor                       
                                                 Test()                       
                                                 {                       
                                                 a =                                     10                                     ;                       
                                                 b =                                     20                                     ;                       
                                                 }                       
                                   
                                                 //Method that returns current class instance                       
                                                 Test get()                       
                                                 {                       
                                                 return                                     this                                     ;                       
                                                 }                       
                                   
                                                 //Displaying value of variables a and b                       
                                                 void                                     display()                       
                                                 {                       
                                                 System.out.println(                                     "a = "                                     + a +                                     "  b = "                                     + b);                       
                                                 }                       
           
                                                 public                                     static                                     void                                     main(String[] args)                       
                                                 {                       
                                                 Test object =                                     new                                     Test();                       
                                                 object.get().display();                       
                                                 }                       
                         }                       

输出：

a = 10  b = 20

4.使用“this”关键字作为方法参数

JAVA

                         // Java code for using 'this'                       
                         // keyword as method parameter                       
                         class                                     Test                       
                         {                       
                                                 int                                     a;                       
                                                 int                                     b;                       
                                   
                                                 // Default constructor                       
                                                 Test()                       
                                                 {                       
                                                 a =                                     10                                     ;                       
                                                 b =                                     20                                     ;                       
                                                 }                       
                                   
                                                 // Method that receives 'this' keyword as parameter                       
                                                 void                                     display(Test obj)                       
                                                 {                       
                                                 System.out.println(                                     "a = "                                     +obj.a +                                     "  b = "                                     + obj.b);                       
                                                 }                       
                                   
                                                 // Method that returns current class instance                       
                                                 void                                     get()                       
                                                 {                       
                                                 display(                                     this                                     );                       
                                                 }                       
           
                                                 public                                     static                                     void                                     main(String[] args)                       
                                                 {                       
                                                 Test object =                                     new                                     Test();                       
                                                 object.get();                       
                                                 }                       
                         }                       

输出：

a = 10  b = 20

5.使用“this”关键字调用当前类方法

JAVA

                         // Java code for using this to invoke current                       
                         // class method                       
                         class                                     Test {                       
           
                                                 void                                     display()                       
                                                 {                       
                                                 // calling function show()                       
                                                 this                                     .show();                       
                                   
                                                 System.out.println(                                     "Inside display function"                                     );                       
                                                 }                       
                                   
                                                 void                                     show() {                       
                                                 System.out.println(                                     "Inside show function"                                     );                       
                                                 }                       
                                   
           
                                                 public                                     static                                     void                                     main(String args[]) {                       
                                                 Test t1 =                                     new                                     Test();                       
                                                 t1.display();                       
                                                 }                       
                         }                       

输出：

Inside show functionInside display function

6.在构造函数调用中使用“this”关键字作为参数

JAVA

                         // Java code for using this as an argument in constructor                       
                         // call                       
                         // Class with object of Class B as its data member                       
                         class                                     A                       
                         {                       
                                                 B obj;                       
                                   
                                                 // Parameterized constructor with object of B                       
                                                 // as a parameter                       
                                                 A(B obj)                       
                                                 {                       
                                                 this                                     .obj = obj;                       
                                   
                                                 // calling display method of class B                       
                                                 obj.display();                       
                                                 }                       
                                   
                         }                       
           
                         class                                     B                       
                         {                       
                                                 int                                     x =                                     5                                     ;                       
                                   
                                                 // Default Constructor that create a object of A                       
                                                 // with passing this as an argument in the                       
                                                 // constructor                       
                                                 B()                       
                                                 {                       
                                                 A obj =                                     new                                     A(                                     this                                     );                       
                                                 }                       
                                   
                                                 // method to show value of x                       
                                                 void                                     display()                       
                                                 {                       
                                                 System.out.println(                                     "Value of x in Class B : "                                     + x);                       
                                                 }                       
                                   
                                                 public                                     static                                     void                                     main(String[] args) {                       
                                                 B obj =                                     new                                     B();                       
                                                 }                       
                         }                       

输出：

Value of x in Class B : 5

本文由 梅哈克·纳朗 和 阿米特·库玛尔 . 如果您发现任何不正确的地方，或者您想分享有关上述主题的更多信息，请写下评论。

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