[練習]IO模塊的練習

要求：

        描述一個學生類，學生類包含學生姓名，數學成績，語文成績，英語成績等屬性，從鍵盤輸入學生對象，然後將輸入的學生對象存入文件，按照總分的大小從大到小排序。

import java.io.*;
import java.util.*;

//描述學生類
class Student implements Comparable<Student>
{
	private String name;
	private int math;
	private int china;
	private int english;
	private int sum;

	public Student(String name, int math, int china, int english){
		this.name = name;
		this.math = math;
		this.china = china;
		this.english = english;
		sum = math + china + english;
	}

	//實現Comparable接口，實現改方法
	public int compareTo(Student s){
		int num = Integer.valueOf(this.sum).compareTo(Integer.valueOf(s.sum));
		if(num == 0){
			return this.name.compareTo(s.name);
		}
		return num;
	} 

	public String toString(){
		return this.name + " : [" + this.math + "," + this.china + "," + this.english + "]";
	}

	public int getSum(){
		return this.sum;
	}
}

class StudentUtil
{
	private static Set<Student> s;
	public StudentUtil(Set<Student> s){
		this.s = s;
	}
	//以“姓名，數學成績，語文成績，英語成績”的形式從鍵盤存入數據
	public static void getStudent() throws Exception{
		BufferedReader bis = new BufferedReader(new InputStreamReader(System.in)); 
		String str = null;
		while((str = bis.readLine()) != null){
			if(str.equals("over")){
				break;
			}
			String[] info = str.split(",");
			Student student = new Student(info[0], Integer.parseInt(info[1]), Integer.parseInt(info[2]), Integer.parseInt(info[3]));
			s.add(student);
		}
		bis.close();
	}

	//將集合中數據寫入文件
	public void writeStudent() throws Exception{
		BufferedWriter bw = new BufferedWriter(new FileWriter("StuInfo.txt"));
		Iterator iterator = s.iterator();
		while(iterator.hasNext()){
			Student s = (Student)iterator.next();
			bw.write(s.toString() + "\t");
			bw.write(s.getSum()+"");
			bw.newLine();
			bw.flush();
		}

		bw.close();
	}
}


class StudentDemo 
{
	public static void main(String[] args) throws Exception
	{
		//獲得從逆向排序的比較器
		Comparator<Student> c = Collections.reverseOrder();
		StudentUtil su = new StudentUtil(new TreeSet<Student>(c));
		su.getStudent();
		System.out.println("獲取成功！");
		su.writeStudent();
		System.out.println("寫入成功！");
	}
}