package day0603; /* 业务层 */ public class StudentService { private StudentDao studentDao = new StudentDao(); public String addStudent(Student student) { //判断学号是否冲突 String id = student.getId(); boolean isExistsResult = isExists(id); return studentDao.addStudent(student); } public boolean isExists(String id) { Student[] students = studentDao.getStudents(); for (Student s:students){ if (s.getId().equals(id)) { return true; } } return false; } public String deleteStudentById(String id) { return studentDao.deleteStudentById(id); } public Student[] selectAllStudents() { return studentDao.getStudents(); } public String updateStudent(Student student) { return studentDao.updateStudent(student); } public Student selectOneById(String id) { return studentDao.selectOneById(id); } }将代码中全部student替换为teacher

替换后的代码如下：

package day0603;

/* 业务层  */
public class TeacherService {
    private TeacherDao teacherDao = new TeacherDao();

    public String addTeacher(Teacher teacher) {
        //判断工号是否冲突
        String id = teacher.getId();
        boolean isExistsResult = isExists(id);
        return teacherDao.addTeacher(teacher);
    }

    public boolean isExists(String id) {
        Teacher[] teachers = teacherDao.getTeachers();
        for (Teacher t:teachers){
            if (t.getId().equals(id)) {
                return true;
            }
        }
        return false;
    }

    public String deleteTeacherById(String id) {
        return teacherDao.deleteTeacherById(id);
    }

    public Teacher[] selectAllTeachers() {
        return teacherDao.getTeachers();
    }

    public String updateTeacher(Teacher teacher) {
        return teacherDao.updateTeacher(teacher);
    }

    public Teacher selectOneById(String id) {
        return teacherDao.selectOneById(id);
    }
}