package test; import java.util.ArrayList; import java.util.Collections; import java.util.Comparator; import java.util.List; class Person {
      private String name;     private int age;     private double score;     public String getName() {
          return name;     }     public void setName(String name) {
          this.name = name;     }     public int getAge() {
          return age;     }     public void setAge(int age) {
          this.age = age;     }     public double getScore() {
          return score;     }     public void setScore(double score) {
          this.score = score;     }     public Person(String name, int age, Double score) {
          this.name = name;         this.age = age;         this.score = score;     }     public String toString(){
          return String.format("name=%s,age=%d,score=%f",name,age,score);     }} public class CompareToDemo {
      public static void main(String[] args) {
          List
    
      list = new ArrayList<>();         list.add(new Person("lisi",28,99.5));         list.add(new Person("lisi",27,99.5));         list.add(new Person("haokun",7,90.5));         list.add(new Person("haokun",7,100.0));         list.add(new Person("aoteman",28,95.0));         Collections.sort(list,new Comparator
     
      (){
             public int compare(Person p1,Person p2){
                 /** if(p1.getName().compareTo(p2.getName())!=0){
                      return p1.getName().compareTo(p2.getName());                 }else if(p1.getAge()-p2.getAge()!=0){
                      return p1.getAge()-p2.getAge();                 }else{
                      return (int)(p1.getScore()-p2.getScore());                 }*/
     
    

　　　　　　　　//写法的改进 　　　　　　　　int nameNum = p1.getName().compareTo(p2.getName());//比较姓名 　　　　　　　　int ageNum = nameNum == 0 ? p1.getAge() - p2.getAge() : nameNum;//比较年龄 　　　　　　　　int scoreNum = ageNum == 0 ? (int) (p1.getScore() - p2.getScore()) : ageNum;//比较分数

　　　　　　　　return scoreNum;             }         });         for(Person p:list){
              System.out.println(p);         }     } }