集合合成的话

List<Article> list1 = new ArrayList<Article>();

 /*.....添加数据.......*/List<Article> list2 = new ArrayList<Article>();  /*.....添加数据.......*/list1.addAll(list2);

 一、被比较对象需实现Comparable接口中的compareTo方法

/*** 根据order对User排序*/public class User implements Comparable
     
      {    private String name;    private Integer order;    public String getName() {        return name;    }    public void setName(String name) {        this.name = name;    }    public Integer getOrder() {        return order;    }    public void setOrder(Integer order) {        this.order = order;    }    public int compareTo(User arg0) {         return this.getOrder().compareTo(arg0.getOrder());     }}
     

测试代码

import java.util.ArrayList;import java.util.Collections;import java.util.List;public class Test{    public static void main(String[] args) {        User user1 = new User();        user1.setName("a");        user1.setOrder(1);        User user2 = new User();        user2.setName("b");        user2.setOrder(2);        List 
     
        list = new ArrayList
      
       ();        //此处add user2再add user1        list.add(user2);        list.add(user1);        for(User u : list){            System.out.println(u.getName());        }        Collections.sort(list);        for(User u : list){            System.out.println(u.getName());        }    }}
      
     

输出结果

b

a

a

b

二、自定义一个比较器Comparator实现compare方法（这里采用匿名内部类的形式）

/*** 根据order对User排序*/public class User {//此处无需实现Comparable接口    private String name;    private Integer order;    public String getName() {        return name;    }    public void setName(String name) {        this.name = name;    }    public Integer getOrder() {        return order;    }    public void setOrder(Integer order) {        this.order = order;    }    }

传入比较器，测试代码

import java.util.ArrayList;import java.util.Collections;import java.util.Comparator;import java.util.List;public class Test{    public static void main(String[] args) {        User user1 = new User();        user1.setName("a");        user1.setOrder(1);        User user2 = new User();        user2.setName("b");        user2.setOrder(2);        List
     
       list = new ArrayList
      
        ();        list.add(user2);        list.add(user1);                 Collections.sort(list,new Comparator
       
        (){            public int compare(User arg0, User arg1) {                return arg0.getOrder().compareTo(arg1.getOrder());            }        });        for(User u : list){            System.out.println(u.getName());        }    }}
       
      
     

三、多属性比较

添加一个id属性

/*** 多属性排序*/public class User {    private Integer id;     private String name;    private Integer order;    public Integer getId() {  return id; } public void setId(Integer id) {  this.id = id; } public String getName() {        return name;    }    public void setName(String name) {        this.name = name;    }        public Integer getOrder() {        return order;    }    public void setOrder(Integer order) {        this.order = order;    }    }

测试代码

import java.util.ArrayList;import java.util.Collections;import java.util.Comparator;import java.util.List;public class Test{    public static void main(String[] args) {        User user1 = new User();        user1.setId(1);        user1.setName("a");        user1.setOrder(1);        User user2 = new User();        user2.setId(2);        user2.setName("a");        user2.setOrder(1);        List
     
       list = new ArrayList
      
        ();        list.add(user2);        list.add(user1);                 Collections.sort(list,new Comparator
       
        (){            public int compare(User arg0, User arg1) {            //第一次比较order               int i = arg0.getOrder().compareTo(arg1.getOrder());                              //如果order相同则比较name               if(i==0){                     int j= arg0.getName().compareTo(arg1.getName());                         //如果name相同则比较id                          if (j==0){                            return arg0.getId().compareTo(arg1.getId());             }             return j;               }               return i;            }        });        for(User u : list){            System.out.println(u.getId());        }    }}
       
      
     

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