MyBatis Plus 学生管理系统实战：从映射文件到控制层

本文将带你一步步搭建一个基于 MyBatis Plus 的学生管理系统，涵盖映射文件、服务层、DAO 层和控制层代码示例，并提供完善的代码补充和配置说明，助你快速上手 MyBatis Plus 开发。

1. 映射文件

<?xml version='1.0' encoding='UTF-8'?>
<!DOCTYPE mapper
        PUBLIC '-//mybatis.org//DTD Mapper 3.0//EN'
        'http://mybatis.org/dtd/mybatis-3-mapper.dtd'>
<mapper namespace='com.example.demo1.mapper.StudentMapper'>

    <resultMap id='BaseResultMap' type='com.example.demo1.domain.Student'>
            <id property='id' column='id' jdbcType='INTEGER'/>
            <result property='name' column='name' jdbcType='VARCHAR'/>
            <result property='no' column='no' jdbcType='VARCHAR'/>
            <result property='gender' column='gender' jdbcType='VARCHAR'/>
            <result property='classId' column='class_id' jdbcType='INTEGER'/>
    </resultMap>

    <sql id='Base_Column_List'>
        id,name,no,
        gender,class_id
    </sql>
</mapper>

2. 服务层

public interface StudentService extends IService<Student> {

}


@Service
public class StudentServiceImpl extends ServiceImpl<StudentMapper, Student>
        implements StudentService {

    @Autowired
    private StudentMapper studentMapper;
//
//    @Override
//    public Student getById(Serializable id) {
//        return studentMapper.selectById(id);
//    }

    @Override
    public Student getById(Serializable id) {
        return super.getById(id);
    }

}

3. DAO 层

@Mapper
public interface StudentMapper extends BaseMapper<Student> {

}

@TableName(value ='tb_student')
public class Student implements Serializable {
    /**
     * 
     */
    @TableId
    private Integer id;

    /**
     * 
     */
    private String name;

    /**
     * 
     */
    private String no;

    /**
     * 
     */
    private String gender;

    /**
     * 
     */
    private Integer classId;

    @TableField(exist = false)
    private static final long serialVersionUID = 1L;

    /**
     * 
     */
    public Integer getId() {
        return id;
    }

    /**
     * 
     */
    public void setId(Integer id) {
        this.id = id;
    }

    /**
     * 
     */
    public String getName() {
        return name;
    }

    /**
     * 
     */
    public void setName(String name) {
        this.name = name;
    }

    /**
     * 
     */
    public String getNo() {
        return no;
    }

    /**
     * 
     */
    public void setNo(String no) {
        this.no = no;
    }

    /**
     * 
     */
    public String getGender() {
        return gender;
    }

    /**
     * 
     */
    public void setGender(String gender) {
        this.gender = gender;
    }

    /**
     * 
     */
    public Integer getClassId() {
        return classId;
    }

    /**
     * 
     */
    public void setClassId(Integer classId) {
        this.classId = classId;
    }

    @Override
    public boolean equals(Object that) {
        if (this == that) {
            return true;
        }
        if (that == null) {
            return false;
        }
        if (getClass() != that.getClass()) {
            return false;
        }
        Student other = (Student) that;
        return (this.getId() == null ? other.getId() == null : this.getId().equals(other.getId()))
            && (this.getName() == null ? other.getName() == null : this.getName().equals(other.getName()))
            && (this.getNo() == null ? other.getNo() == null : this.getNo().equals(other.getNo()))
            && (this.getGender() == null ? other.getGender() == null : this.getGender().equals(other.getGender()))
            && (this.getClassId() == null ? other.getClassId() == null : this.getClassId().equals(other.getClassId()));
    }

    @Override
    public int hashCode() {
        final int prime = 31;
        int result = 1;
        result = prime * result + ((getId() == null) ? 0 : getId().hashCode());
        result = prime * result + ((getName() == null) ? 0 : getName().hashCode());
        result = prime * result + ((getNo() == null) ? 0 : getNo().hashCode());
        result = prime * result + ((getGender() == null) ? 0 : getGender().hashCode());
        result = prime * result + ((getClassId() == null) ? 0 : getClassId().hashCode());
        return result;
    }

    @Override
    public String toString() {
        StringBuilder sb = new StringBuilder();
        sb.append(getClass().getSimpleName());
        sb.append('[');
        sb.append('Hash = ').append(hashCode());
        sb.append(',').append(' id=').append(id);    
        sb.append(',').append(' name=').append(name);    
        sb.append(',').append(' no=').append(no);    
        sb.append(',').append(' gender=').append(gender);    
        sb.append(',').append(' classId=').append(classId);    
        sb.append(',').append(' serialVersionUID=').append(serialVersionUID);    
        sb.append(']');
        return sb.toString();
    }
}

4. 控制层

@RestController
@RequestMapping('/students')
public class StudentController {

    @Autowired
    private StudentService studentService;

    @GetMapping('/{id}')
    public Student getById(@PathVariable('id') Integer id) {
        return studentService.getById(id);
    }

    @PostMapping('/')
    public boolean save(@RequestBody Student student) {
        return studentService.save(student);
    }

    @PutMapping('/')
    public boolean update(@RequestBody Student student) {
        return studentService.updateById(student);
    }

    @DeleteMapping('/{id}')
    public boolean delete(@PathVariable('id') Integer id) {
        return studentService.removeById(id);
    }

}

5. 代码补充和配置说明

导入依赖: 在项目的 pom.xml 文件中添加 MyBatis Plus 的依赖。
配置数据源: 在配置文件中配置数据库连接信息，例如：

spring:
  datasource:
    driver-class-name: com.mysql.cj.jdbc.Driver
    url: jdbc:mysql://localhost:3306/your_database_name?useUnicode=true&characterEncoding=utf-8&serverTimezone=Asia/Shanghai
    username: your_username
    password: your_password

配置 MyBatis Plus: 在配置文件中配置 MyBatis Plus 的相关配置，例如：

mybatis-plus:
  global-config:
    db-config:
      id-type: auto
    mapper-locations: classpath:mapper/**/*.xml
    type-aliases-package: com.example.demo1.domain

注意: 以上代码仅供参考，实际使用时需要根据你的项目情况进行调整。

6. 总结

本文详细介绍了如何使用 MyBatis Plus 搭建一个简单的学生管理系统，并提供了完善的代码示例和配置说明，希望能够帮助你快速上手 MyBatis Plus 开发。