怎样按顺序输出HashMap中值？(请各位指教)

Question

有一个HashMap对象，其中key是一个string对象，value是一个Integer对象，要求写一个方法，输出HashMap对象的值，形式为：key   -- value 
（我想要按顺序输出HashMap中的值（有序）,请各位热心人在此代码上修改，最好能在各位机子上运行通过的全部代码，谢谢！）方法1：
public class HashMapTest {
    
    public static void printPL(Map hm) {
        Set s = hm.keySet();        
        Iterator i = s.iterator();
        while(i.hasNext()) {
            Object o = i.next();
            System.out.println(o +" -- "+hm.get(o));
        }
    }
    
    public static void main(String[] args) {
        HashMap hm = new HashMap();
        hm.put("ha0",new Integer(1000));
        hm.put("ha1",new Integer(1001));
        hm.put("ha2",new Integer(1002));
        hm.put("ha3",new Integer(1003));
        
        printPL(hm);
    }
}方法2：public   class   HashMapTest   {         public   static   void   printPL(Map   hm)   { 
                Set   s   =   hm.entrySet();                 
                Iterator   i   =   s.iterator(); 
                while(i.hasNext())   { 
                        Map.Entry   o   =   (Map.Entry)i.next(); 
                        System.out.println(o.getKey()   +"   --   "+o.getValue()); 
                } 
        }         public   static   void   main(String[]   args)   { 
                HashMap   hm   =   new   HashMap(); 
                hm.put("hao",new   Integer(1000)); 
                hm.put("ha1",new   Integer(1001)); 
                hm.put("ha2",new   Integer(1002)); 
                hm.put("ha3",new   Integer(1003));                 printPL(hm); 
        } 
}

Answer 1

使用TreeMap，自动排序！！！！！

Answer 2

public   class   HashMapTest   {         private HashMap map;        HashMapTest(HashMap map){ this.map = map ; }        public   void   printPL(){ 
                SortedMap<String,Integer> tree = 
                         new TreeMap<String,Integer>(new Comparator<String>() 
                         {                                                 
public int compare(String a,String  b){ return map.get(a).intValue - map.get(b).intValue;}
                         })
                tree.addAll(map);
                Set  s =  tree.entrySet();                                   
                Iterator  i = s.iterator();   
                while(i.hasNext()){   
                      Map.Entry o = (Map.Entry)i.next();   
                      System.out.println(o.getKey()+"--"+o.getValue());   
                                }   
        } 
        
        public   static   void   main(String[]   args)   { 
                HashMap   hm   =   new   HashMap(); 
                hm.put("ha0",new   Integer(1000)); 
                hm.put("ha1",new   Integer(1001)); 
                hm.put("ha2",new   Integer(1002)); 
                hm.put("ha3",new   Integer(1003)); 
                
                new HashMapTest(hm).printPL(); 
        } 
} 
用的treemap  不知道有什么错误没有！ 我没有运行

Answer 3

public   class   HashMapTest   { 
        
        public   static   void   printPL(Map   hm)   { 
                Set   s   =   hm.keySet();                 
                Iterator   i   =   s.iterator(); 
                while(i.hasNext())   { 
                        Object   o   =   i.next(); 
                        System.out.println(o   +"   --   "+hm.get(o)); 
                } 
        } 
        
        public   static   void   main(String[]   args)   { 
                TreeMap   hm   =   new   TreeMap(); 
                hm.put("ha3",new   Integer(1003));
                hm.put("ha0",new   Integer(1000));
                hm.put("ha2",new   Integer(1002)); 
                hm.put("ha1",new   Integer(1001)); 
                printPL(hm); 
        } 
}

Answer 4

不用TreeMap，还有什么其它方法没有，用ArrayList，collections.sort（）怎么具体实现？需要实现的全部代码，谢谢，因为我是菜鸟！

Answer 5

TreeMap是按照key来排序的．import java.util.*;
public       class       HashMapTest       {                   public       static       void       printPL(Map       hm)       {   
                                Set       s       =       hm.entrySet();                                   
                                Iterator       i       =       s.iterator();   
                                while(i.hasNext())       {   
                                                Map.Entry       o       =       (Map.Entry)i.next();   
                                                System.out.println(o.getKey()       +"       --       "+o.getValue());   
                                }   
                }                   public       static       void       main(String[]       args)       {   
                                TreeMap       hm       =       new       TreeMap(); 
                                //hm.put("hao",new       Integer(1000)); //你这里写o了，没有写0，我帮你改了。
                                hm.put("ha0",new       Integer(1000));   
                                hm.put("ha3",new       Integer(1003));   
hm.put("ha1",new       Integer(1001));
hm.put("ha2",new       Integer(1002));
                                printPL(hm);   
                }   
}

Answer 6

你去看API吧，map和ArrayList是不一样的东西．Map是按照key,value存值的，ArrayList是数组的形式，它是实现Collection接口的．key,value存值是实现Map接口的．

Answer 7

把KEY放到TREEMAP里或者任何有排序功能的Array里.排序.然后到你的HashMap里面去get 
不知道为什么一定要用HashMap

Answer 8

http://springjava.javaeye.com/blog/656465  参考例子