IO练习

/**

 *有五个学生，没个学生有三门课的成绩

 *从键盘输入以上信息，姓名，三门课的成绩

 *输入格式：姓名 30 40 60 计算出总成绩

 *并把学生的信息和计算的总分数高低顺序存放在硬盘文件student.txt;

 *

 *1.描述学生对象

 *2.定义一个可以操作学生对象的工具类

 *

 *思想：

 *1.通过获取键盘录入的数据，并将该行中的数据封装成学生对象

 *2.因为学生有很多，需要存储学生的信息，那么就要用到集合，因为要多学生的总分排序

 *可以使用TreeSet

 *3，将集合的信息写入文件中

 */

/**

 * 实体类

 * */

public class Student implements Comparable<Student> {

private String name;

private int ma,cn,en;

private int num;

public Student(String name, int ma, int cn, int en) {

this.name = name;

this.ma = ma;

this.cn = cn;

this.en = en;

this.num = ma+cn+en;

}

public String getName() {

return name;

}

public void setName(String name) {

this.name = name;

}

public int getMa() {

return ma;

}

public void setMa(int ma) {

this.ma = ma;

}

public int getCn() {

return cn;

}

public void setCn(int cn) {

this.cn = cn;

}

public int getEn() {

return en;

}

public void setEn(int en) {

this.en = en;

}

public int getNum() {

return num;

}

public void setNum(int num) {

this.num = num;

}

@Override

public int hashCode() {

return name.hashCode()+num*78;

}

@Override

public boolean equals(Object obj) {

if(!(obj instanceof Student)){

throw new ClassCastException("类型不匹配");

}

Student s= (Student)obj;

return this.name.equals(s.name)&&this.num==s.num;

}

@Override

public int compareTo(Student s) {

int sum = new Integer(this.num).compareTo(new Integer(s.num));

if(sum==0)

return this.name.compareTo(s.name);

return sum;

}

@Override

public String toString() {

return "Student [" + name + ", " + ma + ", " + cn + ","

+ en +"]";

}

}

工具类

import java.util.*;

import java.io.*;

public class StudentInfoTool {

public static Set<Student> getStudents(){

return getStudents(null);

}

public static Set<Student> getStudents(Comparator<Student> cmp) {

// 从键盘录入学生信息

System.out.println("请输入学生信息");         

BufferedReader buffr = new BufferedReader(new InputStreamReader(

System.in));

String line = null;

Set<Student> stus =null;

if(cmp==null)

stus=new TreeSet<Student>();

else

stus=new TreeSet<Student>(cmp);

try {

while ((line = buffr.readLine()) != null) {

if ("over".equals(line))

break;

String[] info = line.split(",");

Student stu = new Student(info[0], Integer.parseInt(info[1]),

Integer.parseInt(info[2]), Integer.parseInt(info[3]));

stus.add(stu);

}

} catch (IOException e) {

throw new RuntimeException("从键盘读取信息失败！");

} finally{

try {

if(buffr!=null)

buffr.close();

} catch (IOException e) {

// TODO Auto-generated catch block

throw new RuntimeException("读取流关闭失败！");

}

}

return stus;

}

public static void writeFile(Set<Student> stus){

BufferedWriter buffw=null;

try {

buffw = new BufferedWriter(new FileWriter( new File("D:\\stuInfo.txt")));

for(Student stu:stus){

buffw.write(stu.toString()+"\t");

buffw.write(stu.getNum()+"");

buffw.newLine();

buffw.flush();

}

 

} catch (IOException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}finally{

try {

buffw.close();

} catch (IOException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

}

}

}

测试类
 public class StudentInfo {

public static void main(String[] args) {

Comparator<Student> cmp=Collections.reverseOrder();

Set<Student> stus= StudentInfoTool.getStudents(cmp);

StudentInfoTool.writeFile(stus);

}

}