List集合根据map里面的一个字段排序

通过实现Comparator接口实现排序，

列子：一个Map 中建 key有name,age 字段，name为名字，age为年龄，现在根据年龄排序代码如下：

@Test
public  void  testMapOrder() {
List> list =  new  ArrayList>();
Map map1 =  new  HashMap();
map1.put( "name" ,  "张三" ); //名字
map1.put( "age" ,  22 );     //年龄
list.add(map1);
Map map3 =  new  HashMap();
map3.put( "name" ,  "王五" );
map3.put( "age" ,  38 );
list.add(map3);
Map map5 =  new  HashMap();
map5.put( "name" ,  "谢七" );
map5.put( "age" ,  20 );
list.add(map5);
Map map6 =  new  HashMap();
map6.put( "name" ,  "张三" );
map6.put( "age" ,  22 );
list.add(map6);
//匿名实现Comparator接口进行排序
Collections.sort(list,  new  Comparator>() {
@Override
public  int  compare(Map o1, Map o2) {
//进行判断
return  ((Integer)o1.get( "age" )).compareTo((Integer)o2.get( "age" ));
}
});
for (Map m:list){
System.out.println( "Map[name=" +m.get( "name" )+ "age=" +m.get( "age" )+ "]" );
}
}

结果：控制台打印

Map[name=谢七age=20]
Map[name=张三age=22]
Map[name=张三age=22]
Map[name=李四age=24]
Map[name=赵六age=36]
Map[name=王五age=38]

 

本文出自 “挺好一个人” 博客，请务必保留此出处http://6913092.blog.51cto.com/6903092/1343919