JAVA中3大集合框架队列的使用

   集合:承载一定数量相同性质对象的容器。

    三大集合框架：List  ,Set ,Map.

一.List集合

   1.List是线性数组队列 ArrayList    LinkedList;

   2.List是Collection的子类

   3.特点：存储的元素是有顺序的，元素都是可以重复的；

public class MapList {/* 定义一个List集合 */public List<String> getList() {List<String> list = new ArrayList<String>();list.add("xie");list.add("zhi");list.add("hua");list.add("Andy Lau");return list;}public void traversingList(List<String> list) {// 方法一：通过下标方式遍历for (int i = 0; i < list.size(); i++) {String st = list.get(i);// System.out.println(st);// System.out.println(list.size());}// 方法二：Iterator迭代器遍历Iterator<String> itr = list.iterator();while (itr.hasNext()) {String str = itr.next();System.out.println(str);}System.out.println(list.size());}public static void main(String[] args) {MapList test = new MapList();// 获取 List集合List<String> list = test.getList();// 遍历List集合并 输出test.traversingList(list);}}

二.Set集合

1.Set是Collection的子类；

2.元素是无序的，元素不能重复；

public class SetList {/** * @param args */public static void main(String[] args) {// TODO Auto-generated method stubSetList test = new SetList();Set<String> set = test.getSet();test.traversingSet(set);}public Set<String> getSet() {Set<String> set = new HashSet<String>();set.add("xie");set.add("zhi");set.add("hua");set.add("Andy Lau");return set;}public void traversingSet(Set<String> set) {// 1.通过迭代器遍历Iterator<String> itr = set.iterator();while (itr.hasNext()) {String st = itr.next();// System.out.println(st);}// 2.通过增强型for语句遍历for (String ste : set) {System.out.println(ste);}}}

三.Map集合

1.键值对应关系存储；

2.键不能重复，值可以重复；

Key.getVaule();

public class MapList1 {/** * @param args */public static void main(String[] args) {// TODO Auto-generated method stubMapList1 test = new MapList1();Map<String, String> map = test.getMap();test.traversingMap(map);}public Map<String, String> getMap() {Map<String, String> map = new HashMap<String, String>();map.put("xie", "drr");map.put("zhi", "ybhu");map.put("hua", "eff");map.put("Andy Lau", "se");return map;}public void traversingMap(Map<String, String> map) {// 1.通过set迭代器集合遍历<迭代Set>Set<String> keySet = map.keySet();Iterator<String> itr = keySet.iterator();while (itr.hasNext()) {String key = itr.next();String value = map.get(key);// System.out.println(key + "," + value);}System.out.println(map.size());// 2.通过set迭代器集合遍历<增强型for语句>for (String key : map.keySet()) {System.out.println(key + "," + map.get(key));}// 3.通过Entry遍历<迭代Entry>for (Entry<String, String> entry : map.entrySet()) {System.out.println(entry + "," + entry.getValue());}}}