再现等答案,希望各位GG帮忙代码: 1.
public interface StudentService{
public Student getStudent(String id);
public void createStudent(Student student);
public java.util.Set getCompletedCourse(Student student);
}
2.
public interface CourserService{
public Course getCourse(String id);
public void createCourse(Course course);
public java.util.Set getAllCourses();
public void errollStudentInCroouse(Course course,Student student)throws CourseException;
}
3.
public class StudentServiceImpl implements StudentService{
private Student Dao studentDao;
public StudentServiceImpl(StudentDao dao)
{ studentDao=dao;}
public void SetStudentDao(StudentDao dao)
{ studentDao=dao;}
punlic Student getStudent(Student student)
{ studentDao.create(student);}
public java.util.Set getCompletedCourse(Student student)
{return studentDao.getCompleteCourse(student);} }4......
......
问题1. 第一段代码public Student getStudent(String id);
这里为什么是返回Student类型的?不是int吗,什么时候返回Student 类 这种类型,有什么好处?问题2. 第三段代码private Student Dao studentDao;
这个算不算内部类? 一般什么时候用到?
public interface StudentService{
public Student getStudent(String id);
public void createStudent(Student student);
public java.util.Set getCompletedCourse(Student student);
}
2.
public interface CourserService{
public Course getCourse(String id);
public void createCourse(Course course);
public java.util.Set getAllCourses();
public void errollStudentInCroouse(Course course,Student student)throws CourseException;
}
3.
public class StudentServiceImpl implements StudentService{
private Student Dao studentDao;
public StudentServiceImpl(StudentDao dao)
{ studentDao=dao;}
public void SetStudentDao(StudentDao dao)
{ studentDao=dao;}
punlic Student getStudent(Student student)
{ studentDao.create(student);}
public java.util.Set getCompletedCourse(Student student)
{return studentDao.getCompleteCourse(student);} }4......
......
问题1. 第一段代码public Student getStudent(String id);
这里为什么是返回Student类型的?不是int吗,什么时候返回Student 类 这种类型,有什么好处?问题2. 第三段代码private Student Dao studentDao;
这个算不算内部类? 一般什么时候用到?
如果你想返回int,只要把student改成int就可以了,这个Student应该是个你自己定义的一个类吧?
2 这个不算内部类,只是定义变量。好处的话你可以百度一下喽
private Student Dao studentDao;
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这应该是书印错了吧,这样定义的没有见过
2。think in java
这应该是个BEAN类型的类,里面有SET,GET方法,你返回这个类型的变量,意味着你可以通过里面的GET方法得到类中的各个属性值,比你直接返回VECTOR,STRING[]...要好的多