检索HashMap中所有键的集合的Java程序
首先，创建一个HashMap并添加元素
HashMap hm = new HashMap();
hm.put("Wallet", new Integer(700));
hm.put("Belt", new Integer(600));
hm.put("Backpack", new Integer(1200));现在，检索所有密钥
Set keys = hm.keySet();
System.out.println("\nKeys...");
Iterator i = keys.iterator();
while (i.hasNext()) {
System.out.println(i.next());
}下面以获取HashMap中所有key的集合为例
示例
import java.util.*;
public class Demo {
public static void main(String args[]) {
//创建哈希映射
HashMap hm = new HashMap();
hm.put("Wallet", new Integer(700));
hm.put("Belt", new Integer(600));
hm.put("Backpack", new Integer(1200));
System.out.println("Map = "+hm);
Set keys = hm.keySet();
System.out.println("\nKeys...");
Iterator i = keys.iterator();
while (i.hasNext()) {
System.out.println(i.next());
}
}
}以下是输出
Map = {Backpack=1200, Belt=600, Wallet=700}
Keys...
Backpack
Belt
Wallet