Java TreeSet學生成績排序

成績排序

• 需求:

  用TreeSet集合存儲多個學生資訊(姓名,國文成績，數學成績，并周遊該集合)

• 要求:

  按照總分從高到低出現

public class Student {
	private String name;
	private int chinese;
	private int math;

	public Student() {}

	public Student(String name, int chinese, int math) {
		super();
		this.name = name;
		this.chinese = chinese;
		this.math = math;
	}

	public String getName() {
		return name;
	}

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

	public int getChinese() {
		return chinese;
	}

	public void setChinese(int chinese) {
		this.chinese = chinese;
	}

	public int getMath() {
		return math;
	}

	public void setMath(int math) {
		this.math = math;
	};
	
	public int getSum() {
		return this.getChinese()+this.getMath();
	}

}
           

public class TreeSetTest {
	public static void main(String[] args) {
		TreeSet<Student> ts = new TreeSet<>(new Comparator<Student>() {
			@Override
			public int compare(Student s1, Student s2) {
				//主要條件
				int num = s2.getSum() - s1.getSum();
				//次要條件
				int num2 = num == 0 ? s1.getChinese() - s2.getChinese() : num;
				int num3 = num2 == 0 ? s1.getName().compareTo(s2.getName()) : num2;
				return num3;
			}
		});

		Student s1 = new Student("1小明", 98, 99);
		Student s2 = new Student("2小紅", 78, 79);
		Student s3 = new Student("3小藍", 88, 89);

		Student s4 = new Student("4小黑", 87, 90);
		Student s5 = new Student("5小白", 87, 90);

		ts.add(s1);
		ts.add(s2);
		ts.add(s3);
		ts.add(s4);
		ts.add(s5);

		for (Student s : ts) {
			System.out.println(s.getName() + "," + s.getChinese() + "," + s.getMath() + "," + s.getSum());
		}

	}
}