Java IdentityHashMap keySet() 方法

7 Jan 2025 | 1 分钟阅读

Java IdentityHashMap 类的 keyset() 方法用于获取调用 IdentityHashMap 中所有键的集合视图。

语法

包含调用 IdentityHashMap 中所有键的集合

示例 1

import java.util.IdentityHashMap;

public class IdentityHashMapKeySetExample1 {
    public static void main(String[] args) {
   //Creating an object of IdentityHashMap class
   IdentityHashMap<String,Integer> map = new IdentityHashMap<String,Integer>(6);
   
   //Putting key-value pairs inside map
   map.put("Java", 1);
   map.put("is", 2);
   map.put("the", 3);
   map.put("best", 4);
   map.put("programming", 5);
   map.put("language", 6);
   
   //All the Linkages in the IdentityHashMap
   System.out.println(map);
   
   //Displaying the set view of all the keys
   System.out.println(map.keySet());
}
}

输出

{Java=1, the=3, language=6, programming=5, best=4, is=2}
[Java, the, language, programming, best, is]

示例 2

import java.util.IdentityHashMap;

class Student{
    private int roll;
    private String name;
    private int standard;
    
    public Student(int roll,String name,int standard){
        this.roll = roll;
        this.name = name;
        this.standard = standard;
    }
    
    public String disp(){
        return roll+" "+name+" "+standard;
    }
}

public class IdentityHashMapKeySetExample2 {
    public static void main(String[] args) {
        Student stud1 = new Student(1 ,"Ram ",10);
        Student stud2 = new Student(2 ,"Shyam ",10);
        Student stud3 = new Student(3 ,"Aman ",12);
        Student stud4 = new Student(4 ,"Harsh ",12);

        //Creating an instance of IdentityHashMap  
        IdentityHashMap<Integer,Student> map = new                IdentityHashMap<Integer,Student>(5);

        //Inserting the Student class objects into IdentityHashMap
        map.put(1,stud1);
        map.put(2,stud2);
        map.put(3,stud3);
        map.put(4,stud4);
        
        //Displaying the set view of all the keys
        System.out.println(map.keySet());
    }
}

输出

[1, 3, 2, 4]

下一主题Java-identityhashmap-isempty-method

Java IdentityHashMap keySet() 方法

语法

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示例 1

示例 2

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Java IdentityHashMap keySet() 方法

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示例 1

示例 2

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