HashMap、LinkedHashMap和TreeMap的实例验证

三个Map接口的常见实现类HashMap、LinkedHashMap和TreeMap
1.HashMap
无序存储，遍历之后的顺序并一定是存储顺序
2.LinkedHashMap
有序存储，遍历之后的顺序是存储时的顺序，因为是使用链表的原理进行的存储
3.TreeMap
自动排序，按照key进行自动排序，使用二叉树储存
下面是他们的代码
1.HashMap
public class test {
public static void main(String[] args) {
Map map1 = new HashMap<Integer, String>();
map1.put(1, "1");
map1.put(2, "2");
map1.put(3, "3");
map1.put(44, "44");
map1.put(6, "6");
map1.put(333, "333");
map1.put(7, "7");
map1.put(33, "33");

Set<Map.Entry<Integer,String>> entrySet = map1.entrySet();
Iterator<Map.Entry<Integer, String>> iterator = entrySet.iterator();
while(iterator.hasNext()){
Entry entry = iterator.next();
System.out.println(entry.getKey()+","+entry.getValue());
}
}
}


控制台输出：
1,1
33,33
2,2
3,3
6,6
7,7
44,44
333,333


2.LinkedHashMap
public class test {
public static void main(String[] args) {
Map map1 = new LinkedHashMap<Integer, String>();
map1.put(1, "1");
map1.put(2, "2");
map1.put(3, "3");
map1.put(44, "44");
map1.put(6, "6");
map1.put(333, "333");
map1.put(7, "7");
map1.put(33, "33");

Set<Map.Entry<Integer,String>> entrySet = map1.entrySet();
Iterator<Map.Entry<Integer, String>> iterator = entrySet.iterator();
while(iterator.hasNext()){
Entry entry = iterator.next();
System.out.println(entry.getKey()+","+entry.getValue());
}
}
}
控制台输出：
1,1
2,2
3,3
44,44
6,6
333,333
7,7
33,33


3.TreeMap
public class test {
public static void main(String[] args) {
Map map1 = new TreeMap<Integer, String>();
map1.put(1, "1");
map1.put(2, "2");
map1.put(3, "3");
map1.put(44, "44");
map1.put(6, "6");
map1.put(333, "333");
map1.put(7, "7");
map1.put(33, "33");

Set<Map.Entry<Integer,String>> entrySet = map1.entrySet();
Iterator<Map.Entry<Integer, String>> iterator = entrySet.iterator();
while(iterator.hasNext()){
Entry entry = iterator.next();
System.out.println(entry.getKey()+","+entry.getValue());
}
}
}


控制台输出：
1,1
2,2
3,3
6,6
7,7
33,33
44,44
333,333