请老师帮忙看一下，这个错在哪？

你好！试了一下你的代码，在Subject类中有和Student类相关的内容，但是你现在的类名是StudentTwo，所以要把Subject中和Student相关的内容都改成StudentTwo才可以。你的代码中是不是还有Student类，所以Subject类没有报编译错误，但是调用addStudent方法时，就会发现参数应该是Student类的对象，而传进去的是StudentTwo类的对象，所以就报错了。

package com.object.project;

public class StudentTwo {

// 成员属性:学生姓名、学生年龄、学生性别、学号

private String studentName;

private int studentAge;

private String studentSex;

private String studentNo;

// 无参构造方法

public StudentTwo() {

}

// 带参构造方法

public StudentTwo(String studentName, int studentAge, String studentSex, String studentNo) {

this.setStudentName(studentName);

this.setStudentAge(studentAge);

this.setStudentSex(studentSex);

this.setStudentNo(studentNo);

}

// get/set方法

public String getStudentName() {

return studentName;

}

public void setStudentName(String studentName) {

this.studentName = studentName;

}

public int getStudentAge() {

return studentAge;

}

public void setStudentAge(int studentAge) {

if (studentAge <= 10||studentAge>=100)

return;

this.studentAge = studentAge;

}

public String getStudentSex() {

return studentSex;

}

public void setStudentSex(String studentSex) {

if (studentSex.equals("男")||studentSex.equals("女")) {

this.studentSex = studentSex;

}else {

this.studentSex="男";

}

}

public String getStudentNo() {

return studentNo;

}

public void setStudentNo(String studentNo) {

this.studentNo = studentNo;

}

public String introduction() {

String str = "学生信息如下：\n姓名：" + this.getStudentName() + "\n学号：" + this.getStudentNo() + "\n年龄："

+ this.getStudentAge() + "岁"+"\n性别：" + this.getStudentSex();

return str;

}

}

package com.object.project;

public class Subject {

// 成员属性：学科名称、学科编号、学制年限、报名学生信息、报名学生个数

private String subjectName;

private String subjectNo;

private int subjectLife;

private Student[] myStudents;

private int studentNum;

// 无参构造方法

public Subject() {

}

// 带参构造方法,实现对学生姓名、学号、学制赋值

public Subject(String subjectName, String subjectNo, int subjectLife) {

this.setSubjectName(subjectName);

this.setSubjectNo(subjectNo);

this.setSubjectLife(subjectLife);

this.setMyStudents(myStudents);

this.setStudentNum(studentNum);

}

// 带参构造方法,实现对全部属性的赋值

public Subject(String subjectName, String subjectNo, int subjectLife,Student[] myStudents) {

this.setSubjectName(subjectName);

this.setSubjectNo(subjectNo);

this.setSubjectLife(subjectLife);

this.setMyStudents(myStudents);

this.setStudentNum(studentNum);

}

// set/get方法

public String getSubjectName() {

return subjectName;

}

public void setSubjectName(String subjectName) {

this.subjectName = subjectName;

}

public String getSubjectNo() {

return subjectNo;

}

public void setSubjectNo(String subjectNo) {

this.subjectNo = subjectNo;

}

public int getSubjectLife() {

return subjectLife;

}

public void setSubjectLife(int subjectLife) {

if (subjectLife <= 0) {

return;

}

this.subjectLife = subjectLife;

}

// 防止获取的数组未被初始化，对其进行限制

public Student[] getMyStudents() {

if (this.myStudents == null) 

this.myStudents = new Student[200];

return myStudents;

}

public void setMyStudents(Student[] myStudents) {

this.myStudents = myStudents;

}

public int getStudentNum() {

return studentNum;

}

public void setStudentNum(int studentNum) {

this.studentNum = studentNum;

}

/**

* 专业介绍的方法

* @return 专业介绍的相关信息，包括专业名称、专业编号、学制年限

*/

public String info() {

String str = "专业信息如下：\n专业名称：" + this.getSubjectName() + "\n专业编号：" + this.getSubjectNo() + "\n学制年限："

+ this.getSubjectLife()+"年";

return str;

}

public void addStudent(StudentTwo stu) {

/*1、把学生信息保存到数组中

* 2、将学生个数保存到studentNum 

*/

//1、把学生信息保存到数组中

for(int i=0;i<this.getMyStudents().length;i++) {

if(this.getMyStudents()[i]==null) {

this.getMyStudents()[i]=stu;

//2、将学生个数保存到studentNum

this.studentNum=i+1;

return;

}

}

}

}

package com.test;

import com.object.project.StudentTwo;

import com.object.project.Subject;

public class SchoolTest {

public static void main(String[] args) {

        //实例化对象one

Subject one = new Subject("人力资源管理","J0123",-6);

if(one.getSubjectLife()==0)

one.setSubjectLife(4);

System.out.println(one.info());

System.out.println("========================");

//实例化对象各个学生

StudentTwo stu1=new StudentTwo("张三",99,"男","123");

if(stu1.getStudentAge()==0) 

stu1.setStudentAge(18);

System.out.println(stu1.introduction());

System.out.println("========================");

StudentTwo stu2=new StudentTwo("李四",18,"女","123");

System.out.println(stu2.introduction());

System.out.println("========================");

StudentTwo stu3=new StudentTwo("王五",19,"男","123");

System.out.println(stu3.introduction());

System.out.println("========================");

//测试指定专业中的学生报名人数

one.addStudent(stu1);

one.addStudent(stu2);

one.addStudent(stu3);

}

}