Java AbstractMap.SimpleEntry getKey()用法及代码示例

AbstractMap.SimpleEntry <K，V>用于维护键和值输入。可以使用setValue方法更改该值。此类有助于构建自定义Map实现。
getKey()AbstractMap.SimpleEntry <K，V>的方法返回与此条目对应的键。

用法:

public K getKey()

参数：此方法不接受任何内容。

返回值：此方法返回与此条目对应的 key 。

以下示例程序旨在说明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); 
        } 
    } 
}

输出：

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); 
        } 
    } 
}

输出：

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

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

相关用法

注：本文由纯净天空筛选整理自AmanSingh2210大神的英文原创作品 AbstractMap.SimpleEntry getKey() Method in Java with Examples。非经特殊声明，原始代码版权归原作者所有，本译文未经允许或授权，请勿转载或复制。