新手求助，编译可以通过，但运行出错

Question

下面是我编写的程序class Student
{
private String name;
private float englishScore;
private float computerScore;
private float historyScore;
private float mathematicsScore;
public void setname(String s)
{
this.name=s;
}
public void setenglishScore(float n)
{
this.englishScore=n;
}
public void setcomputerScore(float n)
{
this.computerScore=n;
}
public void sethistoryScore(float n)
{
this.historyScore=n;
}
public void setmathematicsScore(float n)
{
this.mathematicsScore=n;
}
public String getname()
{
return this.name;
}
public float getenglishScore()
{
return this.englishScore;
}
public float getcomputerScore()
{
return this.computerScore;
}
public float gethistoryScore()
{
return this.historyScore;
}
public float getmathematicsScore()
{
return this.mathematicsScore;
}
public Student(String s)
{
this.setname(s);
}
public float totalScore()
{
float total=this.getenglishScore()+this.getcomputerScore()+this.gethistoryScore()+this.getmathematicsScore();
return total;
}
public float avarageScore()
{
float total=this.getenglishScore()+this.getcomputerScore()+this.gethistoryScore()+this.getmathematicsScore();
float avarage=total/4;
return avarage;
}
public float highScore()
{
float high;
if (this.getenglishScore()>this.getcomputerScore())
{
high=this.getenglishScore();
}else
{
high=this.getcomputerScore();
}
if (high<this.gethistoryScore())
{
high=gethistoryScore();
}
if (high<this.getmathematicsScore())
{
high=getmathematicsScore();
}
return high;
}
public float lowScore()
{
float low;
if (this.getenglishScore()<this.getcomputerScore())
{
low=this.getenglishScore();
}else
{
low=this.getcomputerScore();
}
if (low>this.gethistoryScore())
{
low=gethistoryScore();
}
if (low>this.getmathematicsScore())
{
low=getmathematicsScore();
}
return low;
}
public void PrintStudentInformation()
{
System.out.println("姓名:"+this.getname()+"   英语成绩："+this.getenglishScore()+"   计算机成绩："+this.getcomputerScore()+
                 "    历史成绩"+this.gethistoryScore()+"    数学成绩"+this.getmathematicsScore());
System.out.println("总成绩:"+this.totalScore()+"平均成绩："+this.avarageScore()+"最高分："+this.highScore()+"最低分："+this.lowScore());
}}public class Hello{
public static void main(String arg[]){
Student student1=null;
student1=new Student("sun");
student1.setenglishScore(90.5f);
student1.setcomputerScore(93.5f);
student1.sethistoryScore(88.0f);
student1.setmathematicsScore(99.0f);
student1.PrintStudentInformation();
}
};编译之后文件下面有hello.class与student.class文件，以上程序在Netbeans中可以正确编译与运行，但是在命令行下可以编译通过，运行部了

Answer 1

楼主你好：
student.java   class Student
{
private String name;
private float englishScore;
private float computerScore;
private float historyScore;
private float mathematicsScore;
public void setname(String s)
{
this.name=s;
}
public void setenglishScore(float n)
{
this.englishScore=n;
}
public void setcomputerScore(float n)
{
this.computerScore=n;
}
public void sethistoryScore(float n)
{
this.historyScore=n;
}
public void setmathematicsScore(float n)
{
this.mathematicsScore=n;
}
public String getname()
{
return this.name;
}
public float getenglishScore()
{
return this.englishScore;
}
public float getcomputerScore()
{
return this.computerScore;
}
public float gethistoryScore()
{
return this.historyScore;
}
public float getmathematicsScore()
{
return this.mathematicsScore;
}
public Student(String s)
{
this.setname(s);
}
public float totalScore()
{
float total=this.getenglishScore()+this.getcomputerScore()+this.gethistoryScore()+this.getmathematicsScore();
return total;
}
public float avarageScore()
{
float total=this.getenglishScore()+this.getcomputerScore()+this.gethistoryScore()+this.getmathematicsScore();
float avarage=total/4;
return avarage;
}
public float highScore()
{
float high;
if (this.getenglishScore()>this.getcomputerScore())
{
high=this.getenglishScore();
}else
{
high=this.getcomputerScore();
}
if (high<this.gethistoryScore())
{
high=gethistoryScore();
}
if (high<this.getmathematicsScore())
{
high=getmathematicsScore();
}
return high;
}
public float lowScore()
{
float low;
if (this.getenglishScore()<this.getcomputerScore())
{
low=this.getenglishScore();
}else
{
low=this.getcomputerScore();
}
if (low>this.gethistoryScore())
{
low=gethistoryScore();
}
if (low>this.getmathematicsScore())
{
low=getmathematicsScore();
}
return low;
}
public void PrintStudentInformation()
{
System.out.println("姓名:"+this.getname()+"   英语成绩："+this.getenglishScore()+"   计算机成绩："+this.getcomputerScore()+
                 "    历史成绩"+this.gethistoryScore()+"    数学成绩"+this.getmathematicsScore());
System.out.println("总成绩:"+this.totalScore()+"平均成绩："+this.avarageScore()+"最高分："+this.highScore()+"最低分："+this.lowScore());
}}2、hello.java   public class Hello{
public static void main(String arg[]){
Student student1=null;
student1=new Student("sun");
student1.setenglishScore(90.5f);
student1.setcomputerScore(93.5f);
student1.sethistoryScore(88.0f);
student1.setmathematicsScore(99.0f);
student1.PrintStudentInformation();
}
}如下：执行第一步：打开cmd用管理员权限执行哦！第二步：D:\testjava>javac student.java第三步：D:\testjava>javac hello.java第四步：D:\testjava>java Hello

Answer 2

感谢二楼，我发现我犯了两个错误CMD没有用管理员权限执行
java Hello写出了java hellojava是大小写敏感的，我用hello，java就找不到hello主类，因为主类是Hello