集合框架之Map LinkedHashMap
LinkedHashMap是Map接口的实现类，key以LinkedHashSet存储。
哈希表散列Key，链表维持Key的添加顺序。
LinkedHashMap的添加和遍历：
1 public class Demo1 { 2 3 public static void main(String[] args) { 4 /*HashMap<Student,Object> map=new HashMap<Student,Object>(); 5 Student student=new Student(1,"大明",20); 6 Student student1=new Student(1,"大明",20); 7 Student student2=new Student(3,"舔狗",22); 8 9 ArrayList<String> list=new ArrayList<String>(); 10 list.add("3333"); 11 list.add("444"); 12 map.put(student1, list); 13 map.put(student2, list); 14 map.put(student, list); 15 16 System.out.println(map);*/ 17 18 LinkedHashMap<String,Object> linkedHashMap=new LinkedHashMap<String,Object>(); 19 ArrayList<String> arrayList=new ArrayList<String>(); 20 arrayList.add("333"); 21 arrayList.add("999"); 22 arrayList.add("555"); 23 24 ArrayList<String> arrayList1=new ArrayList<String>(); 25 arrayList1.add("AAA"); 26 arrayList1.add("EEE"); 27 arrayList1.add("QQQ"); 28 29 linkedHashMap.put("1",arrayList); 30 linkedHashMap.put("1",arrayList1); 31 32 Set<String> keys=linkedHashMap.keySet(); 33 /*for (String string : keys) { 34 System.out.println(string+"="+linkedHashMap.get(string)); 35 }*/ 36 java.util.Iterator<String> iterator=keys.iterator(); 37 while(iterator.hasNext()){ 38 String key=iterator.next(); 39 System.out.println(key+"="+linkedHashMap.get(key)); 40 } 41 42 43 } 44 45 }