package day0603; import java.util.Arrays; /* 持久层 */ public class StudentDao { private Student[] students = {}; public String addStudent(Student student) { students = Arrays.copyOf(this.students, students.length + 1); students[students.length-1] = student; return "添加成功"; } public Student[] getStudents(){ return students; } public String deleteStudentById(String id) { int index = getIndex(id); students[index] = students[students.length-1]; students = Arrays.copyOf(students,students.length-1); return "删除成功"; } public String updateStudent(Student student) { String id = student.getId(); int index = getIndex(id); students[index] = student; return "修改成功"; } public Student selectOneById(String id) { int index = getIndex(id); return students[index]; } public int getIndex(String id) { for (int i = 0; i < students.length; i++) { if (students[i].getId().equals(id)) { return i; } } return -1; } }将该代码中的student全部替换为teacher

替换后的代码如下：

package day0603;
import java.util.Arrays;

/* 持久层  */
public class TeacherDao {
    private Teacher[] teachers = {};

    public String addTeacher(Teacher teacher) {
        teachers = Arrays.copyOf(this.teachers, teachers.length + 1);
        teachers[teachers.length-1] = teacher;
        return "添加成功";
    }

    public Teacher[] getTeachers(){
        return teachers;
    }

    public String deleteTeacherById(String id) {
        int index = getIndex(id);
        teachers[index] = teachers[teachers.length-1];
        teachers = Arrays.copyOf(teachers,teachers.length-1);
        return "删除成功";
    }

    public String updateTeacher(Teacher teacher) {
        String id = teacher.getId();
        int index = getIndex(id);
        teachers[index] = teacher;
        return "修改成功";
    }

    public Teacher selectOneById(String id) {
        int index = getIndex(id);
        return teachers[index];
    }

    public int getIndex(String id) {
        for (int i = 0; i < teachers.length; i++) {
            if (teachers[i].getId().equals(id)) {
                return i;
            }
        }
        return -1;
    }
}