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，在這里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， 并在 src/main/resources 下新建一個 Folder mappers 用來放置 MyBatis 的 mapper.xml 文件。

2.1 MyBatis 配置文件

在目錄 src/main/resources 下新建 MyBatis 配置文件 mybatis-config.xml ，在這里主要配置了為 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>

注：在這里，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

到這里我們就完成了 DAO 層的代碼實現，下一節我們將進入 Service 層的實現。

轉載于:https://www.cnblogs.com/wanghuaijun/p/7076746.html

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