開源框架提供的 org.apache.commons.collections.map.ListOrderedMap 可以按key 排序

AtomicInteger為什麼能夠達到多而不亂，處理高併發應付自如呢？
這是由硬體提供原子操作指令實現的。在非激烈競爭的情況下，開銷更小，速度更快。Java.util.concurrent中實現的原子操作類包括：
AtomicBoolean、AtomicInteger、AtomicLong、AtomicReference。

public class TestListOrderedMap {

    public static void main(String[] args) {

        Map<String, String> map = new HashMap<String, String>();
        map.put("1", "Test1");
        map.put("2", "Test2");
        map.put("3", "Test3");
        map.put("4", "Test4");

        Set<Entry<String, String>> entrySet1 = map.entrySet();
        for (Entry<String, String> entry : entrySet1) {
            System.out.println(entry.getKey() + ":" + entry.getValue());
        }

        Map<String, String> listOrderedMap = ListOrderedMap.decorate(new HashMap());
        listOrderedMap.put("1", "Test1");
        listOrderedMap.put("2", "Test2");
        listOrderedMap.put("3", "Test3");
        listOrderedMap.put("4", "Test4");

        Set<Entry<String, String>> entrySet2 = listOrderedMap.entrySet();
        for (Entry<String, String> entry : entrySet2) {
            System.out.println(entry.getKey() + ":" + entry.getValue());
        }
    }
}

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.Comparator;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
 

Map<string, long=""> map = new HashMap<string, long="">();
map.put("c", 33333L);
map.put("a", 11111L);
map.put("d", 44444L);
map.put("e", 55555L);
map.put("b", 22222L);
 
//將map.entrySet()轉換成list
List<map.entry<string, long="">> list = new ArrayList<map.entry<string, long="">>(map.entrySet());
Collections.sort(list, new Comparator<map.entry<string, long="">>() {
	//降序排序
	@Override
	public int compare(Entry<string, long=""> o1, Entry<string, long=""> o2) {
		//return o1.getValue().compareTo(o2.getValue());
		return o2.getValue().compareTo(o1.getValue());
	}
});

for (Map.Entry<string, long=""> mapping : list) {
	System.out.println(mapping.getKey() + ":" + mapping.getValue());
}