自定义list排序方法!

例如：list=[{COUNTTICKET=1, PRECOUNTOUT=2}, {COUNTTICKET=6, PRECOUNTOUT=7}, {COUNTTICKET=7, PRECOUNTOUT=7}, {COUNTTICKET=1, PRECOUNTOUT=1}]

多个字段中的某个字段的排序:

import  java.util.ArrayList;
import  java.util.Collections;
import  java.util.Comparator;
import  java.util.HashMap;
import  java.util.List;
import  java.util.Map;

public  class  $ {

    public  static  void  main(String[] args) {

        List> data =  new  ArrayList>();

        init(data);

        System.out.println( "排序前:" );
        System.out.println(data);
        sort(data);
        System.out.println( "排序后:" );
        System.out.println(data);
    }

    private  static  void  sort(List> data) {

        Collections.sort(data,  new  Comparator() {

            public  int  compare(Map o1, Map o2) {

                Integer a = (Integer) o1.get( "PRECOUNTOUT" );
                Integer b = (Integer) o2.get( "PRECOUNTOUT" );

                // 升序
                return  a.compareTo(b);

                // 降序
                // return b.compareTo(a);
            }
        });
    }

    private  static  void  init(List> data) {

        Map map =  new  HashMap();
        map.put( "COUNTTICKET" ,  1 );
        map.put( "PRECOUNTOUT" ,  2 );
        data.add(map);

        map =  new  HashMap();
        map.put( "COUNTTICKET" ,  6 );
        map.put( "PRECOUNTOUT" ,  7 );
        data.add(map);

        map =  new  HashMap();
        map.put( "COUNTTICKET" ,  8 );
        map.put( "PRECOUNTOUT" ,  5 );
        data.add(map);

        map =  new  HashMap();
        map.put( "COUNTTICKET" ,  2 );
        map.put( "PRECOUNTOUT" ,  3 );
        data.add(map);
    }
}