排序的问题

[danliandejintou]

学号 姓名 成绩
1 张三 80
2 钱六 70
3 王五 60
4 李四 90
=========================
现在要按成绩高低输出，如何排序？

[茫茫大海]

public class Student {
	private String no;
	private String name;
	private double score;
	
	public Student(String no,String name, double score) {
		this.no = no;
		this.name = name;
		this.score = score;
	}

	public String getNo() {
		return no;
	}

	public void setNo(String no) {
		this.no = no;
	}

	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}

	public double getScore() {
		return score;
	}

	public void setScore(double score) {
		this.score = score;
	}
	
	@Override
	public String toString() {
		return no + "    " + name + "    " + score;
	}

}

import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;


public class Main {
	public static void main(String[] args) {
		List<Student> students = new ArrayList<Student>();
		students.add(new Student("1","张三",80));
		students.add(new Student("2","钱六",70));
		students.add(new Student("3","王五",60));
		students.add(new Student("4","李四",90));
		
		//从大到小排序，若是从小到大排序，只需-1和1变换即可。
		Collections.sort(students, new Comparator<Student>() {
			public int compare(Student stu1, Student stu2) {
				if(stu1.getScore() > stu2.getScore()) {
					return -1;
				} else if(stu1.getScore() == stu2.getScore()) {
					return 0;
				} else {
					return 1;
				}
			}
		});
		
		for(Student stu : students) {
			System.out.println(stu);
		}
	}
}

定义一个Student类，来表示一行数据。然后用Collections接口中的sort方法排序，自定义Comparator。