在原题基础上完成1编写Student实体类编写Student实体类有属性idLongsnameStringsageint addressString创建相对于的数据库表主键为id2 参考UserMapper接口创建StudentMapper并完善在StudentMapper接口中添加方法findbyId返回值User对象和findAllList集合findBbySname返回集合可能有重名。3创建

1. Student实体类

public class Student {
    private Long id;
    private String sname;
    private int sage;
    private String address;

    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    public String getSname() {
        return sname;
    }

    public void setSname(String sname) {
        this.sname = sname;
    }

    public int getSage() {
        return sage;
    }

    public void setSage(int sage) {
        this.sage = sage;
    }

    public String getAddress() {
        return address;
    }

    public void setAddress(String address) {
        this.address = address;
    }
}

2. StudentMapper

public interface StudentMapper {
    Student findById(Long id);

    List<Student> findAll();

    List<Student> findBySname(String sname);
}

3. StudentMapper.xml

<mapper namespace="com.example.mapper.StudentMapper">
    <select id="findById" resultType="com.example.entity.Student">
        select * from student where id = #{id}
    </select>

    <select id="findAll" resultType="com.example.entity.Student">
        select * from student
    </select>

    <select id="findBySname" resultType="com.example.entity.Student">
        select * from student where sname = #{sname}
    </select>
</mapper>

4. StudentService接口和StudentServiceImpl实现类

public interface StudentService {
    Student getStudent(Long id);

    List<Student> getStudents();

    List<Student> getStudentsBySname(String sname);
}

@Service
public class StudentServiceImpl implements StudentService {
    @Autowired
    private StudentMapper studentMapper;

    @Override
    public Student getStudent(Long id) {
        return studentMapper.findById(id);
    }

    @Override
    public List<Student> getStudents() {
        return studentMapper.findAll();
    }

    @Override
    public List<Student> getStudentsBySname(String sname) {
        return studentMapper.findBySname(sname);
    }
}

5. StudentController

@Controller
@RequestMapping("/students")
public class StudentController {
    @Autowired
    private StudentService studentService;

    @RequestMapping("/index")
    public ModelAndView allList(HttpSession session) {
        ModelAndView mav = new ModelAndView();
        User user = (User) session.getAttribute("user");
        if (user != null) {
            List<Student> students = studentService.getStudents();
            mav.addObject("students", students);
            mav.setViewName("students");
        } else {
            mav.setViewName("index");
        }
        return mav;
    }
}
``