来源

 

//可以使用Collections.sort(List list, Comparator c)来实现

这里举例hashmap中存的一个时间的键值,按照时间的值来排序

//先写个类实现Comparator,并重写compare(Object o1, Object o2)方法,在方法中自定义比较逻辑

public class MyComparator implements Comparator {@Override    public int compare(Object o1, Object o2) {    // TODO Auto-generated method stub        int result = 0;        SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");        try {            HashMap
     
       map1 = (HashMap
      
       ) o1, map2 = (HashMap
       
        ) o2;            Date map1_time = format.parse(map1.get("time"));            Date map2_time = format.parse(map2.get("time"));            if(map1_time.after(map2_time)){                result = -1;            }else if(map1_time.before(map2_time)){                result = 1;            }else if(map1_time.equals(map2_time)){                result = 0;            }        } catch (Exception e) {        // TODO: handle exception            e.printStackTrace();        }        return result;    }}
       
      
     

调用的时候Collections.sort(List对象, new MyComparator());