list排序

ArrayList bcDataset = new ArrayList();
Map f1 = new HashMap();
f1.put("date", "2015-09-15");f1.put("name", "fdsa");
Map f2 = new HashMap();
f2.put("date", "2015-01-15");f2.put("name", "jdsa");
Map f3 = new HashMap();
f3.put("date", "2015-02-15");f3.put("name", "zdsa");
Map f4 = new HashMap();
f4.put("date", "2015-12-15");f4.put("name", "ddsa");
Map f5 = new HashMap();
f5.put("date", "2015-03-15");f5.put("name", "mdsa");
bcDataset.add(f1);bcDataset.add(f2);bcDataset.add(f3);bcDataset.add(f4);
bcDataset.add(f5);
Collections.sort(bcDataset, new Comparator<HashMap>(){


@Override
public int compare(HashMap o1, HashMap o2) {
return o1.get("date").toString().compareTo(o2.get("date").toString());
}});
HashMap m1 = null; 
for (int i = 0; i < bcDataset.size(); i++) {
m1 = (HashMap)bcDataset.get(i);
System.out.println(m1.get("date")+","+m1.get("name"));
}