大家帮我看看为什么报异常 - 黑马程序员技术交流社区

<div class="blockcode"><blockquote>import java.io.*;
import java.util.*;
import java.lang.*;
public class Test31
{
public static void main(String[] args) throws IOException
{
Set<Student> students=StudentTool.getStudent();
StudentTool.write2file(students);
}
}
class Student implements Comparable<Student>
{
String name;
int ma,cn,en;
int sum;
public Student(String name,int ma,int cn,int en){
this.name=name;
this.ma=ma;
this.cn=cn;
this.en=en;
this.sum=ma+cn+en;
}
public String getName(){
return name;
}
public int getSum(){
return sum;
}
public int hashCode(){
return name.hashCode()+sum*78;
}
public boolean equals(Object obj){
if(!(obj instanceof Student))
throw new ClassCastException("你输入的类有问题");
Student s=(Student)obj;
return this.name.equals(s.name)&& this.sum==s.sum;
}
public int compareTo(Student s){
<font color="red">int n=new Integer(this.name).compareTo(new Integer(s.sum));</font>
if(n==0)
return this.name.compareTo(s.name);
else
return n;
}
public String toString(){
return "student["+name+"-"+ma+"-"+cn+"-"+en+"]";
}
}
class StudentTool
{
public static Set<Student> getStudent()throws IOException{
BufferedReader buff=new BufferedReader(new InputStreamReader(System.in));
String line=null;
Set <Student> students=new TreeSet<Student>();
while((line=buff.readLine())!=null){
//BufferedReader buff=new BufferedReader(new InputStreamReader(System.in));
if(line.equals("ober")){
break;
}
String []stu=line.split(",");
//System.out.println(stu[0],Integer.parseInt(stu[1]),Integer.parseInt(stu[2]));
Student s=new Student(stu[0],Integer.parseInt(stu[1]),Integer.parseInt(stu[2]),Integer.parseInt(stu[3]));
students.add(s);
}
buff.close();
return students;
}
public static void write2file(Set<Student> set)throws IOException{
File f=new File("a.txt");
f.createNewFile();
BufferedWriter buf=new BufferedWriter(new FileWriter(f));
for(Student s:set){
buf.write(s.toString());
buf.write(s.getSum());
buf.newLine();
buf.flush();
}
buf.close();
}
}

复制代码