简单的学生成绩统计程序

今天在CSDN上面回答了一个小问题，是一个学生的作业。他自己的描述如下：

1.编写一个程序:要求从DOS控制台以提问对话的形式，输入三个同学的c语言成绩与java成绩,并将成绩保存到一个“chengji.txt”的文件中.


2.提示：1.创建一个Student学生类，其中域变量包括name,age,javaScore和cScore；

2.创建一个TestChengji类，在main主方法中分别创建三个对象数组：

Student []stu=new Student[3];

stu[] = new Student(    );

String []javaScore=new String[3];

String []cScore=new String[3];

将控制台输入的数据保存在数组中，然后在保存到一个文件中。


3.根据上面的程序，编写一个程序，从文件chengji.txt中取出三个同学的成绩，并求出平均成绩输出到dos控制台上显示出来。

 

下面的代码是我写的，很不完善，缺少必要的验证机制，但是实现了他说的基本功能。

记录在这里，以后说不定有用呢。呵呵

/**
 * 
 * @author kanpiaoxue
 * Date 2013-11-27
 * 
 */
public class Student {
	private String name;
	private int age;
	private double javaScore;
	private double cScore;

	public Student() {
		super();
	}

	public Student(String name, int age, double javaScore, double cScore) {
		super();
		this.name = name;
		this.age = age;
		this.javaScore = javaScore;
		this.cScore = cScore;
	}

	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 getJavaScore() {
		return javaScore;
	}

	public void setJavaScore(double javaScore) {
		this.javaScore = javaScore;
	}

	public double getCScore() {
		return cScore;
	}

	public void setCScore(double cScore) {
		this.cScore = cScore;
	}

}

 

import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.List;

import org.apache.commons.io.IOUtils;

import com.alibaba.fastjson.JSON;

/**
 * 
 * @author kanpiaoxue
 * Date 2013-11-27
 * 
 */
public class TestChengji {
	private static final String DATA_FILE = "D:\\tmp\\students.txt";

	/**
	 * 
	 * 连续提问学生的姓名，年龄，java成绩，C成绩。当输入stop的时候，结束，并计算结果
	 * 
	 * 
	 * @throws Exception
	 */
	public static void main(String[] args) throws Exception {
		TestChengji t = new TestChengji();
		List students = t.createStudents();
		t.saveStudentsToFile(students);
		students = t.readStudentsFromFile();
		t.calculateStudents(students);
		/**
		 * 
		 * 
		 * 下面是程序的运行结果：
		 * 
		 * Please enter student name :student1
		 * Please enter student age :20
		 * Please enter student java score :98
		 * Please enter student C score :89
		 * Do you continue enter student infomation? (yes/no) : yes
		 * Please enter student name :student2
		 * Please enter student age :20
		 * Please enter student java score :90
		 * Please enter student C score :88
		 * Do you continue enter student infomation? (yes/no) : yes
		 * Please enter student name :student3
		 * Please enter student age :20
		 * Please enter student java score :85
		 * Please enter student C score :85
		 * Do you continue enter student infomation? (yes/no) : no
		 * stop enter students infomation.
		 * write datas to D:\tmp\students.txt successfully!
		 * start reading students infomation from D:\tmp\students.txt
		 * 3 students java average score : 91.0, c average score : 87.33333333333333
		 * 
		 * 
		 */
	}

	/**
	 * @param reader
	 * @return
	 * @throws Exception
	 *             创建学生。 这里呢，我没有给你校验学生的age，javaScore，cScore的合法性。你可以自己进行校验。
	 */
	private Student createStudent(BufferedReader reader) throws Exception {
		System.out.print("Please enter student name :");
		String str = null;
		Student student = new Student();
		str = reader.readLine();
		student.setName(str);
		System.out.print("Please enter student age :");
		str = reader.readLine();
		student.setAge(Integer.valueOf(str));

		System.out.print("Please enter student java score :");
		str = reader.readLine();
		student.setJavaScore(Double.valueOf(str));

		System.out.print("Please enter student C score :");
		str = reader.readLine();
		student.setCScore(Double.valueOf(str));

		return student;
	}

	private List createStudents() {
		List list = new ArrayList();
		BufferedReader reader = null;
		try {
			reader = new BufferedReader(new InputStreamReader(System.in));
			Student student = createStudent(reader);
			list.add(student);

			System.out
					.print("Do you continue enter student infomation? (yes/no) : ");
			String str = reader.readLine();
			if (str.trim().equalsIgnoreCase("no")
					|| str.trim().equalsIgnoreCase("n")) {
				System.out.println("stop enter students infomation.");
				return list;
			} else {
				List l = createStudents();
				list.addAll(l);
			}
		} catch (Exception e) {
			e.printStackTrace();
		} finally {
			if (null != reader) {
				try {
					reader.close();
				} catch (IOException e) {
				}
			}
		}
		return list;
	}

	private void saveStudentsToFile(List students) throws Exception {
		File f = new File(DATA_FILE);
		f.delete();
		f.createNewFile();
		if (f.isFile()) {
			FileWriter writer = new FileWriter(f);
			for (Student s : students) {
				String json = JSON.toJSONString(s);
				writer.write(json + "\n");
			}
			writer.flush();
			writer.close();
			System.out.println("write datas to " + f + " successfully!");
		} else {
			throw new IllegalArgumentException("please check file " + f);
		}

	}

	private List readStudentsFromFile() throws Exception {
		File f = new File(DATA_FILE);
		System.out.println("start reading students infomation from " + f);
		@SuppressWarnings("unchecked")
		List lines = IOUtils.readLines(new FileInputStream(f));
		List list = new ArrayList();
		for (String str : lines) {
			Student s = JSON.parseObject(str, Student.class);
			list.add(s);
		}
		return list;
	}

	private void calculateStudents(List students) {
		double javaSum = 0D;
		double cSum = 0D;
		for (Student s : students) {
			javaSum += s.getJavaScore();
			cSum += s.getCScore();
		}
		int size = students.size();
		System.out.println(size + " students java average score : "
				+ (javaSum / size) + ", c average score : " + (cSum / size));
	}
}