/*  * To change this template, choose Tools | Templates  * and open the template in the editor.  */ package cn.tsp2c.liubao; import java.util.Collection; import java.util.HashMap; import java.util.Iterator; import java.util.Map; import java.util.Set; import java.util.TreeMap; /**  *  * @author Administrator  */ public class TestMap {     public static void main(String[] args) {         Map<String, Student> map = new HashMap<String, Student>();         Student s1 = new Student("宋江", "1001", 38);         Student s2 = new Student("卢俊义", "1002", 35);         Student s3 = new Student("吴用", "1003", 34);         map.put("1001", s1);         map.put("1002", s2);         map.put("1003", s3);         Map<String, Student> subMap = new HashMap<String, Student>();         subMap.put("1008", new Student("tom", "1008", 12));         subMap.put("1009", new Student("jerry", "1009", 10));         map.putAll(subMap);         work(map);         workByKeySet(map);         workByEntry(map);     } //最常规的一种遍历方法，最常规就是最常用的，虽然不复杂，但很重要，这是我们最熟悉的，就不多说了！！     public static void work(Map<String, Student> map) {         Collection<Student> c = map.values();         Iterator it = c.iterator();         for (; it.hasNext();) {             System.out.println(it.next());         }     } //利用keyset进行遍历，它的优点在于可以根据你所想要的key值得到你想要的 values，更具灵活性！！     public static void workByKeySet(Map<String, Student> map) {         Set<String> key = map.keySet();         for (Iterator it = key.iterator(); it.hasNext();) {             String s = (String) it.next();             System.out.println(map.get(s));         }     } 　　//比较复杂的一种遍历在这里，呵呵~~他很暴力哦，它的灵活性太强了，想得到什么就能得到什么~~     public static void workByEntry(Map<String, Student> map) {         Set<Map.Entry<String, Student>> set = map.entrySet();         for (Iterator<Map.Entry<String, Student>> it = set.iterator(); it.hasNext();) {             Map.Entry<String, Student> entry = (Map.Entry<String, Student>) it.next();             System.out.println(entry.getKey() + "--->" + entry.getValue());         }     } } class Student {     private String name;     private String id;     private int age;     public Student(String name, String id, int age) {         this.name = name;         this.id = id;         this.age = age;     }     @Override     public String toString() {         return "Student{" + "name=" + name + "id=" + id + "age=" + age + '}';     } }