map的使用方法

package cn.stat.p8.map.demo;

import java.util.Collection;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;

public class MapDemo2 {

public static void main(String[] args) {
Map<Integer,String> mapset=new HashMap<Integer,String>();
method_2(mapset);
}

private static void method(Map<Integer, String> mapset) {
mapset.put(8,"list");
mapset.put(9,"list6");
mapset.put(3,"list2");
mapset.put(6,"list7");
mapset.put(1,"list9");

Set<Map.Entry<Integer,String>> ks=mapset.entrySet();
Iterator<Map.Entry<Integer,String>> it=ks.iterator();
while(it.hasNext())
{
Map.Entry<Integer,String>  me=it.next();

Integer  key=me.getKey();
String value=me.getValue();

System.out.println(value+"  "+key);
}
}
public static void method_2(Map<Integer, String> mapset) {
mapset.put(8,"list");
mapset.put(9,"list6");
mapset.put(3,"list2");
mapset.put(6,"list7");
mapset.put(1,"list9");
Collection<String> values=mapset.values();
Iterator<String> it2=values.iterator();
while(it2.hasNext())
{
System.out.println(it2.next());
}
}

}

package cn.stat.p7.map.demo;

import java.util.HashMap;
import java.util.Map;
import java.util.TreeMap;

public class MapDemo {

/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
Map<Integer,String> map=new TreeMap<Integer,String>();
method(map);
}
public static void method(Map<Integer,String> map)
{
//添加
System.out.println(map.put(8,"wangcai"));
System.out.println(map.put(8,"xiaoxiao"));
map.put(2, "lili");
map.put(9, "niuniu");

System.out.println(map);

//删除
System.out.println(map.remove(2));

System.out.println(map);

//判断
System.out.println("containskey:"+map.containsKey(8));
System.out.println("containsvalues:"+map.containsValue("222"));

//获取
System.out.println(map.get(8));//不存在返回null
}

}