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package com.pancm.basics;

import java.util.HashMap;

import java.util.Iterator;

import java.util.Map;

import java.util.Map.Entry;

import java.util.TreeMap;

/**

*

* Title: MapTest

* Description:集合map测试

* Version:1.0.0

* @author pancm

* @date 2017年11月16日

*/

public class MapTest {

private static Map<String,String> map = new HashMap<String,String>();

public static Map<String,String> getHashMap(){

if(map == null || map.isEmpty()){

map = new HashMap<String,String>();

}

return map;

}

public static void main(String[] args) {

//普通的HashMap

// Map<String,String> map=mapTest.getHashMap();

// map.put("a", "1");

// map.put("b", "1");

// map.put("c", "e");

// System.out.println(map.toString());

// Map<String,String> map1=mapTest.getHashMap();

// System.out.println("-----"+map1.get("a"));

//上锁的HashMap

// Map<String,String> sMap=Collections.synchronizedMap(new HashMap());

// getMap1();

test1();

test2();

}

private static void test1() {

Map<String, String> map = new HashMap<String, String>();

map.put("1", "value1");

map.put("2", "value2");

map.put("3", "value3");

//第一种：普遍使用，二次取值

System.out.println("通过Map.keySet遍历key和value：");

for (String key : map.keySet()) {

System.out.println("key= "+ key + " and value= " + map.get(key));

}

//第二种 使用迭代器Iterator进行遍历

System.out.println("通过Map.entrySet使用iterator遍历key和value：");

Iterator<Map.Entry<String, String>> it = map.entrySet().iterator();

while (it.hasNext()) {

Map.Entry<String, String> entry = it.next();

System.out.println("key= " + entry.getKey() + " and value= " + entry.getValue());

}

//第三种：使用entrySet遍历 推荐，尤其是容量大时

System.out.println("通过Map.entrySet遍历key和value");

for (Map.Entry<String, String> entry : map.entrySet()) {

System.out.println("key= " + entry.getKey() + " and value= " + entry.getValue());

}

}

private static void test2() {

Map<String,Object> hashMap=new HashMap<String,Object>();

hashMap.put("a", 1);

hashMap.put("c", 3);

hashMap.put("b", 2);

System.out.println("HashMap:"+hashMap);

Map<String,Object> treeMap=new TreeMap<String,Object>();

treeMap.put("a", 1);

treeMap.put("c", 3);

treeMap.put("b", 2);

System.out.println("TreeMap:"+treeMap);

}

@SuppressWarnings("unused")

private static void getMap1(){

Map<Integer,Integer> map1 =new HashMap<Integer,Integer>();

Map<Integer,Integer> map2 =new HashMap<Integer,Integer>();

map1.put(1, 1);

map1.put(2, 2);

map1.put(3, 3);

map2.put(11, 11);

map2.put(22, 22);

map2.put(33, 33);

Map<Integer,Map<Integer,Integer>> map3 =new HashMap<Integer,Map<Integer,Integer>>();

map3.put(1, map1);

map3.put(2, map2);

System.out.println("map3:"+map3);

StringBuffer sb=new StringBuffer();

for(Entry<Integer,Map<Integer,Integer>> entry:map3.entrySet()){

sb.append(entry.getKey());

sb.append(":");

Map<Integer,Integer> map4=entry.getValue();

for(Entry<Integer,Integer> entry1:map4.entrySet()){

sb.append(entry1.getKey());

sb.append("_");

sb.append(entry1.getValue());

sb.append(",");

}

}

sb.deleteCharAt(sb.lastIndexOf(","));

System.out.println("sb:"+sb);

}

}