人员管理系统 - 部门管理业务实现

在sm.service中entity中新建一个实体类Department，设置好setter和geter方法

在Dao包中编写持久层的增删改查的接口DepartmentDao

@Repository("departmentDao")
public interface DepartmentDao {
  void insert(Department department);
  void delete(Integer id);
  void update(Department department);
  Department selectById(Integer id);
  List<Department> selectAll();
}

由于整合了mybatis开发，所以要在resources中创建一个mapper.xml，在文件中实现具体的操作

<?xml version="1.0" encoding="utf-8" ?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.4//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.imooc.sm.dao.DepartmentDao">
    <!--实体类和表的对应关系-->
    <resultMap id="resultMap" type="Department">
        <!--如果对应数据库中的字段是主键的话，就用id这个标签-->
        <id property="id" column="id" javaType="Integer"/>
        <result property="name" column="name" javaType="String"/>
        <result property="address" column="address" javaType="String"/>
    </resultMap>
    <!--配置sql-->
    <!--useGeneratedKeys="true" insert要引入自增-->
    <insert id="insert"  parameterType="Department" useGeneratedKeys="true" keyProperty="id">
        insert into department(name,address) values(#{name},#{address})
    </insert>

    <delete id="delete" parameterType="Integer" >
        delete from department where id = #{id}
    </delete>

    <update id="update" parameterType="Department">
        update department set name = #{name},address=#{address} where id = #{id}
    </update>

    <select id="selectById" parameterType="Integer" resultMap="resultMap">
        select * from department where id = #{id}
    </select>

    <select id="selectAll" resultMap="resultMap">
        select * from department
    </select>
</mapper>

3.在service中编写DepartmentService接口
大部分情况下，service接口中的方法与dao中的方法大致上是一致的。

public interface DepartmentService {
    void add(Department department);
    void remove(Integer id);
    void edit(Department department);
    Department get(Integer id);
    List<Department> getAll();
}

实现DepartmentService接口

package com.imooc.sm.service.impl;
import com.imooc.sm.dao.DepartmentDao;
import com.imooc.sm.entity.Department;
import com.imooc.sm.service.DepartmentService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import java.util.List;
@Service("departmentService")
public class DepartmentServiceImpl implements DepartmentService {
  @Autowired
  private DepartmentDao departmentDao;
  public void add(Department department) {
      departmentDao.insert(department);
  }

  public void remove(Integer id) {
      departmentDao.delete(id);
  }

  public void edit(Department department) {
      departmentDao.update(department);
  }

  public Department get(Integer id) {

      return departmentDao.selectById(id);
  }

  public List<Department> getAll() {

      return departmentDao.selectAll();
  }
}

4.这里需要添加spring标签的地方有：

dao层中要添加@Repository("departmentDao")
service层中要添加的是@Service("departmentService")

这里出现里两个错误
- 在mapper.xml也是departmentDao的文件的xml映射文件中的错误，id属性没有写colmun
- resources这个资源文件路径下mapper.xml要与departmentDao的路径一致。在创建包时要com/imooc/sm/dao
  参考一下解释：
  IDEA中关于mapper.xml文件和dao接口路径及文件名相同的问题
  https://blog.csdn.net/MrSuper_cat/article/details/104436318/