说明:此处的排序 是指:
1: 往集合中插入元素的顺序与遍历元素的顺序的关系;
2: 往对象中插入元素否会根据元素的大小排序
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public class MapSortTest {
public static void main(String[] args) {
System.out.println("放入顺序为:a:aaa c:ccc b:bbb d:ddd ");
System.out.println("HashMap 排序测试");
Map map = new HashMap();
map.put("a", "aaa");
map.put("c", "ccc");
map.put("b", "bbb");
map.put("d", "ddd");
Iterator iterator = map.keySet().iterator();
while (iterator.hasNext()) {
Object key = iterator.next();
System.out.println("key:"+key+" value:" + map.get(key));
}
System.out.println("HashMap 进出无次序 ; key大小无次序 ");
System.out.println("***********************************************************");
System.out.println("Hashtable 排序测试");
Hashtable tab = new Hashtable();
tab.put("a", "aaa");
tab.put("c", "ccc");
tab.put("b", "bbb");
tab.put("d", "ddd");
Iterator iterator_1 = tab.keySet().iterator();
while (iterator_1.hasNext()) {
Object key = iterator_1.next();
System.out.println("key :"+key+" value:"+ tab.get(key));
}
System.out.println("Hashtable 进出无次序 ; key大小无次序 ");
System.out.println("***********************************************************");
System.out.println("TreeMap 排序测试");
TreeMap tmp = new TreeMap();
tmp.put("a", "aaa");
tmp.put("c", "ccc");
tmp.put("b", "bbb");
tmp.put("d", "ddd");
Iterator iterator_2 = tmp.keySet().iterator();
while (iterator_2.hasNext()) {
Object key = iterator_2.next();
System.out.println("key:"+key+" value:" + tmp.get(key));
}
System.out.println("TreeMap 进出无次序 ; key大小从小到大 ");
System.out.println("***********************************************************");
System.out.println("LinkedHashMap 排序测试");
LinkedHashMap linkedHashMap = new LinkedHashMap();
linkedHashMap.put("a", "aaa");
linkedHashMap.put("c", "ccc");
linkedHashMap.put("b", "bbb");
linkedHashMap.put("d", "ddd");
Iterator iterator2 = linkedHashMap.keySet().iterator();
while (iterator2.hasNext()) {
Object key = iterator2.next();
System.out.println("key:"+key+" value:" + linkedHashMap.get(key));
}
System.out.println("LinkedHashMap 先进先出; key大小无次序 ");
System.out.println();
System.out.println("ArrayList 排序测试");
System.out.println("放入顺序为:aaa ccc bbb ddd");
ArrayList arrayList=new ArrayList();
arrayList.add("aaa");
arrayList.add("ccc");
arrayList.add("bbb");
arrayList.add("ddd");
System.out.println("ArrayList 先进先出;值大小无次序 ");
// Collections.sort(arrayList);
for(int i=0;i<arrayList.size();i++){
System.out.println(arrayList.get(i));
}
System.out.println("***********************************************************");
}
}
运行结果:
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放入顺序为:a:aaa c:ccc b:bbb d:ddd
HashMap 排序测试
key:d value:ddd
key:b value:bbb
key:c value:ccc
key:a value:aaa
HashMap 进出无次序 ; key大小无次序
***********************************************************
Hashtable 排序测试
key :b value:bbb
key :a value:aaa
key :d value:ddd
key :c value:ccc
Hashtable 进出无次序 ; key大小无次序
***********************************************************
TreeMap 排序测试
key:a value:aaa
key:b value:bbb
key:c value:ccc
key:d value:ddd
TreeMap 进出无次序 ; key大小从小到大
***********************************************************
LinkedHashMap 排序测试
key:a value:aaa
key:c value:ccc
key:b value:bbb
key:d value:ddd
LinkedHashMap 先进先出; key大小无次序
ArrayList 排序测试
放入顺序为:aaa ccc bbb ddd
LinkedHashMap 先进先出;值大小无次序
aaa
ccc
bbb
ddd
***********************************************************