DAO 層實現
一、實驗介紹
1.1 實驗內容
本節課程主要利用 MyBatis 框架實現 DAO 層。
1.2 實驗知識點
- MyBatis 框架
- MySQL
1.3 實驗環境
- JDK1.8
- Eclipse JavaEE
二、實驗步驟
根據第一節,我們可以知道系統的功能包括了哪些,根據第三節和第四節,我們知道了數據庫表的結構和持久化實體,因此,在這裏我們完成數據庫的訪問操作。
首先在項目 hrms
的 Java Resources
目錄的 src/main/java
下新建包 com.shiyanlou.dao
,作為 DAO 層的包, 並在 src/main/resources
下新建一個 Folder mappers
2.1 MyBatis 配置文件
在目錄 src/main/resources
下新建 MyBatis 配置文件 mybatis-config.xml
,在這裏主要配置了為 JavaBean 取別名,代碼如下:
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
<!-- 為JavaBean 起類別名 -->
<typeAliases>
<package name="com.shiyanlou.domain" />
</typeAliases>
</configuration>
註:在這裏,我們沒有配置 MyBatis 的運行環境、數據源等,那是因為我們要將這些交給 Spring 進行配置管理。
2.2 AdminDao 接口
在包 com.shiyanlou.dao
下建一個 AdminDao.java
接口文件,代碼如下:
package com.shiyanlou.dao;
import java.util.List;
import java.util.Map;
import org.springframework.stereotype.Repository;
import com.shiyanlou.domain.Admin;
@Repository
public interface AdminDao {
/** 登錄
*
* @param admin
* @return
*/
public Admin login(Admin admin);
/** 根據條件查詢管理員
*
* @param map
* @return
*/
public List<Admin> findAdmins(Map<String, Object> map);
/** 根據條件查詢管理員人數
*
* @param map
* @return
*/
public Integer getCount(Map<String, Object> map);
/** 添加管理員
*
* @param admin
* @return
*/
public Integer addAdmin(Admin admin);
/** 修改管理員
*
* @param admin
* @return
*/
public Integer updateAdmin(Admin admin);
/** 刪除管理員
*
* @param id
* @return
*/
public Integer deleteAdmin(Integer id);
}
接著在 src/main/resources/mappers
路徑下新建與 AdminDao 接口對應的映射文件 AdminMapper.xml
,代碼如下:
<?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.shiyanlou.dao.AdminDao">
<!-- 自定義結果集 -->
<resultMap type="Admin" id="AdminResult">
<id property="id" column="admin_id" />
<result property="username" column="username" />
<result property="password" column="password" />
<result property="role_name" column="role_name" />
</resultMap>
<!-- 登錄 -->
<select id="login" parameterType="Admin" resultMap="AdminResult">
select * from
admin_tb where username=#{username} and password=#{password} limit 1
</select>
<!-- 根據條件查詢管理員 -->
<select id="findAdmins" parameterType="Map" resultMap="AdminResult">
select * from admin_tb
<where>
<if test="username!=null and username!=‘‘ ">
username like #{username}
</if>
</where>
</select>
<!-- 根據條件查詢管理員的人數 -->
<select id="getCount" parameterType="Map" resultType="Integer">
select count(*) from admin_tb
<where>
<if test="username!=null and username!=‘‘ ">
username like #{username}
</if>
</where>
</select>
<!-- 添加管理員 -->
<insert id="addAdmin" useGeneratedKeys="true" keyProperty="admin_id">
insert into admin_tb(username,password)
values(#{username},#{password})
</insert>
<!-- 修改管理員 -->
<update id="updateAdmin" parameterType="Admin">
update admin_tb set
username=#{username},password=#{password} where admin_id=#{id}
</update>
<!-- 刪除管理員 -->
<delete id="deleteAdmin" parameterType="Integer">
delete from admin_tb where
admin_id=#{id}
</delete>
</mapper>
2.3 PostDao 接口
在包 com.shiyanlou.dao
下建一個 PostDao.java
接口文件,代碼如下:
package com.shiyanlou.dao;
import java.util.List;
import java.util.Map;
import org.springframework.stereotype.Repository;
import com.shiyanlou.domain.Post;
@Repository
public interface PostDao {
/** 根據條件查詢公告
*
* @return
*/
public List<Post>findPosts(Map<String, Object> map);
/** 根據條件查詢公告數量
*
* @param map
* @return
*/
public Integer getCount(Map<String, Object> map);
/** 添加公告
*
* @param post
* @return
*/
public Integer addPost(Post post);
/** 修改公告
*
* @param post
* @return
*/
public Integer updatePost(Post post);
/** 刪除公告
*
* @param id
* @return
*/
public Integer deletePost(Integer id);
/** 根據 ID 查詢公告信息
*
* @param id
* @return
*/
public Post getPostById(Integer id);
}
接著在 src/main/resources/mappers
路徑下新建與 PostDao 接口對應的映射文件 PostMapper.xml
,代碼如下:
<?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.shiyanlou.dao.PostDao">
<!-- 自定義結果集 -->
<resultMap type="Post" id="PostResult">
<id property="id" column="post_id" />
<result property="title" column="title" />
<result property="content" column="content" />
<result property="date" column="create_date" />
<association property="admin" javaType="Admin">
<id property="id" column="admin_id" />
<result property="username" column="username" />
</association>
</resultMap>
<!-- 根據條件查詢公告 -->
<select id="findPosts" parameterType="Map" resultMap="PostResult">
select a.admin_id,a.username,p.post_id,p.title,p.content,p.create_date
from admin_tb a,post_tb p where p.admin_id = a.admin_id
<if test="title!=null and title!=‘‘ ">
and p.title like #{title}
</if>
</select>
<!-- 根據條件查詢公告數量 -->
<select id="getCount" parameterType="Map" resultType="Integer">
select count(*) from post_tb
<where>
<if test="title!=null and title!=‘‘ ">
title like #{title}
</if>
</where>
</select>
<!-- 添加公告 -->
<insert id="addPost" useGeneratedKeys="true" keyProperty="post_id">
insert
into post_tb(title,content,admin_id,create_date)
values(#{title},#{content},#{admin.id},#{date})
</insert>
<!-- 修改公告 -->
<update id="updatePost" parameterType="Post">
update post_tb set
title=#{title},content=#{content},admin_id=#{admin.id},create_date=#{date}
where post_id=#{id}
</update>
<!-- 刪除公告 -->
<delete id="deletePost" parameterType="Integer">
delete from post_tb
where
post_id=#{id}
</delete>
<!-- 根據 ID 查詢公告信息 -->
<select id="getPostById" parameterType="Integer" resultMap="PostResult">
select a.admin_id,a.username,p.post_id,p.title,p.content,p.create_date
from admin_tb a,post_tb p where p.admin_id = a.admin_id and
p.post_id=#{id}
</select>
</mapper>
2.4 DepartmentDao 接口
在包 com.shiyanlou.dao
下建一個 DepartmentDao.java
接口文件,代碼如下:
package com.shiyanlou.dao;
import java.util.List;
import java.util.Map;
import org.springframework.stereotype.Repository;
import com.shiyanlou.domain.Department;
@Repository
public interface DepartmentDao {
/** 根據條件查詢部門
*
* @param map
* @return
*/
public List<Department> findDepartments(Map<String, Object> map);
/** 根據條件查詢部門數量
*
* @param map
* @return
*/
public Integer getCount(Map<String, Object> map);
/** 添加部門
*
* @param department
* @return
*/
public Integer addDepartment(Department department);
/** 修改部門
*
* @param department
* @return
*/
public Integer updateDepartment(Department department);
/** 刪除部門
*
* @param id
* @return
*/
public Integer deleteDepartment(Integer id);
}
接著在 src/main/resources/mappers
路徑下新建與 DepartmentDao 接口對應的映射文件 DepartmentMapper.xml
,代碼如下:
<?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.shiyanlou.dao.DepartmentDao">
<!-- 自定義結果集 -->
<resultMap type="Department" id="DepartmentResult">
<id property="id" column="dept_id" />
<result property="name" column="dept_name" />
<result property="description" column="dept_description" />
</resultMap>
<!-- 根據條件查詢部門 -->
<select id="findDepartments" parameterType="Map" resultMap="DepartmentResult">
select * from dept_tb
<where>
<if test="name!=null and name!=‘‘ ">
dept_name like #{name}
</if>
</where>
</select>
<!-- 根據條件查詢部門數量 -->
<select id="getCount" parameterType="Map" resultType="Integer">
select count(*) from dept_tb
<where>
<if test="name!=null and name!=‘‘ ">
dept_name like #{name}
</if>
</where>
</select>
<!-- 添加部門 -->
<insert id="addDepartment" useGeneratedKeys="true" keyProperty="dept_id">
insert into dept_tb(dept_name,dept_description)
values(#{name},#{description})
</insert>
<!-- 修改部門 -->
<update id="updateDepartment" parameterType="Department">
update dept_tb set
dept_name=#{name},dept_description=#{description} where dept_id=#{id}
</update>
<!-- 刪除部門 -->
<delete id="deleteDepartment" parameterType="Integer">
delete from dept_tb where
dept_id=#{id}
</delete>
</mapper>
2.5 PositionDao 接口
在包 com.shiyanlou.dao
下建一個 PositionDao.java
接口文件,代碼如下:
package com.shiyanlou.dao;
import java.util.List;
import java.util.Map;
import org.springframework.stereotype.Repository;
import com.shiyanlou.domain.Position;
@Repository
public interface PositionDao {
/** 根據條件查詢職位
*
* @param map
* @return
*/
public List<Position> findPositions(Map<String, Object> map);
/** 根據條件查詢職位數量
*
* @param map
* @return
*/
public Integer getCount(Map<String, Object> map);
/** 添加職位
*
* @param position
* @return
*/
public Integer addPosition(Position position);
/** 修改職位
*
* @param position
* @return
*/
public Integer updatePosition(Position position);
/** 刪除職位
*
* @param id
* @return
*/
public Integer deletePosition(Integer id);
}
接著在 src/main/resources/mappers
路徑下新建與 PositionDao 接口對應的映射文件 PositionMapper.xml
,代碼如下:
<?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.shiyanlou.dao.PositionDao">
<!-- 自定義結果集 -->
<resultMap type="Position" id="PositionResult">
<id property="id" column="pos_id" />
<result property="name" column="pos_name" />
<result property="description" column="pos_description" />
</resultMap>
<!-- 根據條件查詢職位 -->
<select id="findPositions" parameterType="Map" resultMap="PositionResult">
select * from position_tb
<where>
<if test="name!=null and name!=‘‘ ">
pos_name like #{name}
</if>
</where>
</select>
<!-- 根據條件查詢職位數量 -->
<select id="getCount" parameterType="Map" resultType="Integer">
select count(*) from position_tb
<where>
<if test="name!=null and name!=‘‘ ">
pos_name like #{name}
</if>
</where>
</select>
<!-- 添加職位 -->
<insert id="addPosition" useGeneratedKeys="true" keyProperty="pos_id">
insert into position_tb(pos_name,pos_description)
values(#{name},#{description})
</insert>
<!-- 修改職位 -->
<update id="updatePosition" parameterType="Position">
update position_tb set
pos_name=#{name},pos_description=#{description} where pos_id=#{id}
</update>
<!-- 刪除職位 -->
<delete id="deletePosition" parameterType="Integer">
delete from position_tb where
pos_id=#{id}
</delete>
</mapper>
2.6 EmployeeDao 接口
在包 com.shiyanlou.dao
下建一個 EmployeeDao.java
接口文件,代碼如下:
package com.shiyanlou.dao;
import java.util.List;
import java.util.Map;
import org.springframework.stereotype.Repository;
import com.shiyanlou.domain.Employee;
import com.shiyanlou.domain.Post;
@Repository
public interface EmployeeDao {
/** 根據條件查詢員工
*
* @param map
* @return
*/
public List<Post>findEmployees(Map<String, Object> map);
/** 根據條件查詢員工數量
*
* @param map
* @return
*/
public Integer getCount(Map<String, Object> map);
/** 添加員工
*
* @param employee
* @return
*/
public Integer addEmployee(Employee employee);
/** 修改員工
*
* @param employee
* @return
*/
public Integer updateEmployee(Employee employee);
/** 刪除員工
*
* @param id
* @return
*/
public Integer deleteEmployee(String id);
}
接著在 src/main/resources/mappers
路徑下新建與 EmployeeDao 接口對應的映射文件 EmployeeMapper.xml
,代碼如下:
<?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.shiyanlou.dao.EmployeeDao">
<!-- 自定義結果集 -->
<resultMap type="Employee" id="EmployeeResult">
<id property="id" column="emp_id" />
<result property="name" column="emp_name" />
<result property="sex" column="sex" />
<result property="phone" column="phone" />
<result property="email" column="email" />
<result property="address" column="address" />
<result property="education" column="education" />
<result property="birthday" column="birthday" />
<!-- 關聯映射:association -->
<association property="department" javaType="Department">
<id property="id" column="dept_id" />
<result property="name" column="dept_name" />
</association>
<association property="position" javaType="Position">
<id property="id" column="pos_id" />
<result property="name" column="pos_name" />
</association>
</resultMap>
<!-- 根據條件查詢員工 -->
<select id="findEmployees" parameterType="Map" resultMap="EmployeeResult">
select e.emp_id,e.emp_name,e.sex,e.phone,e.email,e.address,e.education,e.birthday,d.dept_id,d.dept_name,p.pos_id,p.pos_name
from employee_tb e,dept_tb d,position_tb p where e.dept_id = d.dept_id
and e.pos_id = p.pos_id
<if test="id!=null and id!=‘‘ ">
and e.emp_id like #{id}
</if>
<if test="name!=null and name!=‘‘ ">
and e.emp_name like #{name}
</if>
<if test="department_name!=null and department_name!=‘‘ ">
and d.dept_name like #{department_name}
</if>
<if test="position_name!=null and position_name!=‘‘ ">
and p.pos_name like #{position_name}
</if>
<if test="sex!=null and sex!=‘‘ ">
and e.sex like #{sex}
</if>
</select>
<!-- 根據條件查詢員工人數 -->
<select id="getCount" parameterType="Map" resultType="Integer">
select count(*) from employee_tb e,dept_tb d,position_tb p where
e.dept_id = d.dept_id
and e.pos_id = p.pos_id
<if test="id!=null and id!=‘‘ ">
and e.emp_id like #{id}
</if>
<if test="name!=null and name!=‘‘ ">
and e.emp_name like #{name}
</if>
<if test="sex!=null and sex!=‘‘ ">
and e.sex like #{sex}
</if>
</select>
<!-- 添加員工 -->
<insert id="addEmployee" parameterType="Employee">
insert
into employee_tb(emp_id,emp_name,sex,phone,email,address,education,birthday,dept_id,pos_id)
values(#{id},#{name},#{sex},#{phone},#{email},#{address},#{education},#{birthday},#{department.id},#{position.id})
</insert>
<!-- 修改員工 -->
<update id="updateEmployee" parameterType="Employee">
update employee_tb set
emp_name=#{name},sex=#{sex},phone=#{phone},email=#{email},address=#{address},education=#{education},birthday=#{birthday},dept_id=#{department.id},pos_id=#{position.id}
where emp_id=#{id}
</update>
<!-- 刪除員工 -->
<delete id="deleteEmployee" parameterType="String">
delete from employee_tb
where
emp_id=#{id}
</delete>
</mapper>
三、實驗總結
到這裏我們就完成了 DAO 層的代碼實現,下一節我們將進入 Service 層的實現。
DAO 層實現