Java AbstractMap.SimpleEntry getKey()用法及代碼示例

AbstractMap.SimpleEntry <K，V>用於維護鍵和值輸入。可以使用setValue方法更改該值。此類有助於構建自定義Map實現。
getKey()AbstractMap.SimpleEntry <K，V>的方法返回與此條目對應的鍵。

用法:

public K getKey()

參數：此方法不接受任何內容。

返回值：此方法返回與此條目對應的 key 。

以下示例程序旨在說明getKey()方法：
程序1:

// Java program to demonstrate 
// AbstractMap.SimpleEntry.getKey() method 
  
import java.util.*; 
import java.util.AbstractMap.SimpleEntry; 
  
public class GFG { 
  
    @SuppressWarnings({ "unchecked", "rawtypes" }) 
    public static void main(String[] args) 
    { 
  
        // create a ArrayList of Map 
        ArrayList<AbstractMap 
                      .SimpleEntry<Integer, Integer> > 
            arrayList 
            = new ArrayList<AbstractMap 
                                .SimpleEntry<Integer, Integer> >(); 
  
        // add values 
        arrayList.add(new AbstractMap.SimpleEntry(0, 123)); 
        arrayList.add(new AbstractMap.SimpleEntry(1, 130)); 
        arrayList.add(new AbstractMap.SimpleEntry(2, 994)); 
  
        // print keys 
        for (int i = 0; i < arrayList.size(); i++) { 
  
            // get map from list 
            AbstractMap.SimpleEntry<Integer, Integer> 
                map 
                = arrayList.get(i); 
  
            // get key from map.getKey(); 
            int key = map.getKey(); 
  
            System.out.println("Key " + key); 
        } 
    } 
}

輸出：

Key 0
Key 1
Key 2

程序2:

// Java program to demonstrate 
// AbstractMap.SimpleEntry.get() method 
  
import java.util.*; 
  
public class GFG { 
  
    @SuppressWarnings({ "unchecked", "rawtypes" }) 
    public static void main(String[] args) 
    { 
  
        // create a ArrayList of Map 
        ArrayList<AbstractMap 
                      .SimpleEntry<String, String> > 
            arrayList 
            = new ArrayList<AbstractMap 
                                .SimpleEntry<String, String> >(); 
  
        // add values 
        arrayList.add(new AbstractMap 
                          .SimpleEntry(" 001AB ", " Emp 1")); 
        arrayList.add(new AbstractMap 
                          .SimpleEntry(" 011AC ", " Emp 2")); 
        arrayList.add(new AbstractMap 
                          .SimpleEntry(" 111AD ", " Emp 3")); 
        arrayList.add(new AbstractMap 
                          .SimpleEntry(" 101BE ", " Emp 4")); 
        arrayList.add(new AbstractMap 
                          .SimpleEntry(" 110CE ", " Emp 5")); 
  
        // print keys 
        for (int i = 0; i < arrayList.size(); i++) { 
  
            // get map from list 
            AbstractMap.SimpleEntry<String, String> 
                map 
                = arrayList.get(i); 
  
            // get key from map.getKey() 
            String key = map.getKey(); 
  
            System.out.println("Key " + key); 
        } 
    } 
}

輸出：

Key  001AB 
Key  011AC 
Key  111AD 
Key  101BE 
Key  110CE

參考文獻： https://docs.oracle.com/javase/10/docs/api/java/util/AbstractMap.SimpleEntry.html#getKey()

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注：本文由純淨天空篩選整理自AmanSingh2210大神的英文原創作品 AbstractMap.SimpleEntry getKey() Method in Java with Examples。非經特殊聲明，原始代碼版權歸原作者所有，本譯文未經允許或授權，請勿轉載或複製。