public class MapText {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Map<String, String>map = new HashMap<>();
        
        Emp emp = new Emp("351", "張三");
        Emp emp2 = new Emp("512", "李四");
        Emp emp3 = new Emp("853", "王一");
        Emp emp4 
 
= new Emp("125", "趙六");
        Emp emp5 = new Emp("341", "黃七");
        
        map.put(emp.getE_id(), emp.getE_name());
        map.put(emp2.getE_id(), emp2.getE_name());
        map.put(emp3.getE_id(), emp3.getE_name());
        map.put(emp4.getE_id(), emp4.getE_name());
        map.put(emp5.getE_id(), emp5.getE_name());
        
        Set
 
<String>set = map.keySet();
        Iterator<String> it = set.iterator();
        System.out.println("HashMap類實現Map集合,無序:");
        while(it.hasNext()){
            String str = (String)it.next();
            String name = (String)map.get(str);
            System.out.println(str + " " + name);
        }
        TreeMap
 
<String, String> treeMap = new TreeMap<>();
        treeMap.putAll(map);
        Iterator<String> iter = treeMap.keySet().iterator();
        System.out.println("TreeMap類實現的Map集合，鍵對象升序: ");
        while(iter.hasNext()){
            String str = (String)iter.next();
            String name = (String)treeMap.get(str);
            System.out.println(str + " " + name);
        }
        
        
    }

}

Map接口的類實現