我希望要一个ArrayList<Entry>，类似C++中的pair，

可是Map.Entry是个接口，不能实例化，能够像以下这样写

HashMap<Integer, Integer> G = new HashMap<Integer,Integer>();
G.put(1, 9); G.put(4, 6); G.put(2, 8);G.put(3, 7);    
ArrayList<Map.Entry<Integer, Integer>> arrayList = new 
        ArrayList<Map.Entry<Integer, Integer>(G.entrySet());

ArrayList<Map.Entry<Integer, Integer>> arrayList = new 
    ArrayList<Map.Entry<Integer, Integer>>();
arrayList.add(new AbstractMap.SimpleEntry(1, 9));

Map<String, Integer> map = new HashMap<String, Integer>();
map.put("d", 2);
map.put("c", 1);
map.put("b", 1);
map.put("a", 3);

List<Map.Entry<String, Integer>> infoIds =
    new ArrayList<Map.Entry<String, Integer>>(map.entrySet());

//排序前
for (int i = 0; i < infoIds.size(); i++) {
    String id = infoIds.get(i).toString();
    System.out.println(id);
}
//d 2
//c 1
//b 1
//a 3

//排序
Collections.sort(infoIds, new Comparator<Map.Entry<String, Integer>>() {   
    public int compare(Map.Entry<String, Integer> o1, Map.Entry<String, Integer> o2) {      
        //return (o2.getValue() - o1.getValue()); 
        return (o1.getKey()).toString().compareTo(o2.getKey());
    }
}); 

//排序后
for (int i = 0; i < infoIds.size(); i++) {
    String id = infoIds.get(i).toString();
    System.out.println(id);
}
//依据key排序
//a 3
//b 1
//c 1
//d 2
//依据value排序
//a 3
//d 2
//b 1
//c 1

List<Map.Entry<String,Double>> termls = new ArrayList<Map.Entry<String,Double>>();
			for(String s: tf.get(i).keySet()) {
				termls.add(new AbstractMap.SimpleEntry(s, tf.get(i).get(s)*1.0*Math.log10(count*1.0/df.get(s))));
			}
			Collections.sort(termls, new Comparator<Map.Entry<String, Double>>(){
				public int compare(Map.Entry<String, Double> o1,Map.Entry<String, Double> o2){
					return(o2.getValue().compareTo(o1.getValue()));
				}
				
			}
			);
			System.out.println("line " + (i+1));
			for (int ind = 0; ind < termls.size(); ++ind){
				System.out.print(termls.get(ind).toString()+"  ");
			}
			System.out.println();