Java基础进阶-ArrayList集合存储学生对象，要求按照学习成绩进行排序。

淩亂°似流年 2023-07-25 09:53 7阅读 0赞

/\*

*  要求：用ArrayList集合存储学生对象，并对其进行排序，总分成绩由低到高，当成绩
 *  相同时，根据姓名排序。
 *  \*/

上代码…

import java.util.ArrayList;
    import java.util.Collections;
    import java.util.Comparator;
    public class ArrayListDeom {
        
        public static void main(String[] args) {
        
            ArrayList<Student1> arrList = new ArrayList<Student1>();
            Student1 s1 = new Student1("tangsan",99,88);
            Student1 s2 = new Student1("xiaowu",78,99);
            Student1 s3 = new Student1("ningrongrong",100,89);
            Student1 s4 = new Student1("xiaoao",99,78);
    
            arrList.add(s1);
            arrList.add(s2);
            arrList.add(s3);
            arrList.add(s4);
    
            for(int i=0;i<arrList.size();i++){
        
                System.out.println(arrList.get(i).getName()+","+arrList.get(i).allScore());
            }
            System.out.println("----------------");
    
            //传入比较器，自定义比较方法
            Collections.sort(arrList, new Comparator<Student1>() {
        
                @Override
                public int compare(Student1 t1, Student1 t2) {
        
                    double num = t1.allScore()-t2.allScore();
                    double num2 = num==0? t1.getName().compareTo(t2.getName()):num;
                    if(num2>0){
        
                        return 1;
                    }else if(num2<0){
        
                        return -1;
                    }else{
        
                        return 0;
                    }
                }
            });
            for(int i=0;i<arrList.size();i++){
        
                System.out.println(arrList.get(i).getName()+","+arrList.get(i).allScore());
            }
        }
    }

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