List集合对象根据字段排序

//把需要比较的对象实现Comparable接口实现compareTo方法

public class Address implements Comparable<Address> {
String country;
String city;
String name;

public Address(String country, String city, String name) {
super();
this.country = country;
this.city = city;
this.name = name;
}

public String toString(){
return "\nname:"+this.name+" city:"+this.city+" country:"+this.country;
}

@Override
public int compareTo(Address o) {
  //如果国家不相等,那么直接比较其他字段
  if(!this.country.equals(o.country)){
    return this.country.compareTo(o.country);
  }else if(!this.city.equals(o.city)){
    return this.city.compareTo(o.city);
  }else{
    return this.name.compareTo(o.name);
  }
  }
}

//测试类
public class ComparableTest {
public static void main(String[] args) {
  List<Address> list = new ArrayList<Address>();
  Address a1 = new Address("中国", "湖南", "屌丝1");
  Address a2 = new Address("中国", "湖北", "屌丝2");
  Address a3 = new Address("美国", "纽约", "屌丝3");
  Address a4 = new Address("中国", "湖北", "屌丝4");
  Address a5 = new Address("中国", "湖南", "屌丝5");
  Address a6 = new Address("中国", "广西", "屌丝6");
  list.add(a1);
  list.add(a2);
  list.add(a3);
  list.add(a4);
  list.add(a5);
  list.add(a6);

  System.out.println(list);//排序前
  Collections.sort(list);
  System.out.println(list);//排序后

  }
 }
}

 

//打印结果

 

[ name:屌丝1 ncity:湖南 ncountry:中国,

name:屌丝2 ncity:湖北 ncountry:中国,

name:屌丝3 ncity:纽约 ncountry:美国,

name:屌丝4 ncity:湖北 ncountry:中国,

name:屌丝5 ncity:湖南 ncountry:中国,

name:屌丝6 ncity:广西 ncountry:中国]


[ name:屌丝6 ncity:广西 ncountry:中国,

name:屌丝2 ncity:湖北 ncountry:中国,

name:屌丝4 ncity:湖北 ncountry:中国,

name:屌丝1 ncity:湖南 ncountry:中国,

name:屌丝5 ncity:湖南 ncountry:中国,

name:屌丝3 ncity:纽约 ncountry:美国]

 

 

 

 

 

posted @ 2014-04-07 23:57  莫名字  阅读(3153)  评论(0编辑  收藏  举报