package com.yang.mapdemo;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Map.Entry;
public class MapDemo {
public static void main(String[] args) {
Map<String, String> map = new HashMap<String, String>();
map.put("1", "first");
map.put("2", "second");
map.put("3", "third");
//1.通过Map.keySet遍历key和value
for(String key : map.keySet()){
System.out.println("key="+key+", value="+map.get(key));
}
//2.通过Map.entrySet使用iterator遍历key和value
System.out.println("-------------------");
Iterator<Map.Entry<String, String>> it = map.entrySet().iterator();
while(it.hasNext()){
Entry<String, String> entry = it.next();
System.out.println("key="+entry.getKey()+", value="+entry.getValue());
}
//3.通过Map.entrySet遍历key和value(推荐,尤其是容量大时)
System.out.println("-------------------");
for(Map.Entry<String,String> entrySet : map.entrySet()){
System.out.println("key="+entrySet.getKey()+", value="+entrySet.getValue());
}
//4.通过Map.values()遍历所有的value,但不能遍历key
System.out.println("-------------------");
for(String a : map.values()){
System.out.println("value="+a);
}
}
}
java中遍历map的四种方法
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转载自blog.csdn.net/yangymy/article/details/72358585
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