Map的用法
package Java_Container;
import java.util.*;
public class Map_Container {
public static void main(String[] args){
Map map=new HashMap<>();
map.put("hello",1);
map.put("nihao",2);
map.replace("nihao",5);
for(String key:map.keySet()){ //map的遍历方式1
System.out.println(key);
System.out.println(map.get(key));
}
//map的遍历方式2
Iterator iterator=map.keySet().iterator();
while (iterator.hasNext()){
String key=(String) iterator.next();
System.out.println(map.get(key));
}
//按照key值升序排列
Set set=map.keySet();
Object[] a=set.toArray();
Arrays.sort(a);
for(Object key:a){
System.out.println(key);
}
}
}
