feat(database): 配置数据库连接外部化并实现resultMap查询功能

- 将数据库连接信息从config.xml移至db.properties配置文件
- 在config.xml中添加properties资源引用实现配置外部化
- 为Department、Major、Student、Notice四个模块添加resultMap查询方法
- 创建TestMyBatisQueryResultMap测试类验证resultMap查询功能
- 更新SQL映射文件添加resultMap定义和相关查询语句
- 实现基于resultMap的按ID查询和查询所有数据功能

grademanagement-MyBatisProject/src/com/ssm/mapper/DepartmentMapper.java

@@ -13,4 +13,7 @@ public interface DepartmentMapper {
     void updateDepartment(Department department);
     // 删除院系
     void deleteDepartment(Integer deptId);
+    //resultMap方式查询
+    Department getDepartmentMapById(Integer deptId);
+    List<Department> getDepartmentMapAll();
 }

grademanagement-MyBatisProject/src/com/ssm/mapper/DepartmentMapper.xml

@@ -3,9 +3,11 @@
         PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
         "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
 <mapper namespace="com.ssm.mapper.DepartmentMapper">
+    <!-- 按ID查询-->
     <select id="getDepartmentById" resultType="com.ssm.entity.Department" parameterType="Integer">
         SELECT * FROM department WHERE dept_id = #{deptId}
     </select>
+    <!-- 查询所有 -->
     <select id="getDepartmentAll" resultType="com.ssm.entity.Department">
         SELECT * FROM department
     </select>
@@ -27,4 +29,21 @@
     <delete id="deleteDepartment" parameterType="Integer">
         DELETE FROM department WHERE dept_id = #{deptId}
     </delete>
+    <!--resultMap映射-->
+    <resultMap id="DepartentResult" type="com.ssm.entity.Department">
+        <id property="deptId" column="dept_id"/>
+        <result property="deptName" column="dept_name"/>
+        <result property="deptCode" column="dept_code"/>
+        <result property="deptPhone" column="dept_phone"/>
+        <result property="deptAddress" column="dept_address"/>
+    </resultMap>
+    <!-- 按ID查询（使用resultMap） -->
+    <select id="getDepartmentMapById" resultMap="DepartentResult" parameterType="Integer">
+        SELECT * FROM department WHERE dept_id = #{deptId}
+    </select>
+    <!-- 查询所有（使用resultMap） -->
+    <select id="getDepartmentMapAll" resultMap="DepartentResult" >
+        SELECT * FROM department
+    </select>
+
 </mapper>

grademanagement-MyBatisProject/src/com/ssm/mapper/MajorMapper.java

@@ -1,4 +1,5 @@
 package com.ssm.mapper;
+import com.ssm.entity.Department;
 import com.ssm.entity.Major;
 import java.util.List;
 
@@ -11,4 +12,7 @@ public interface MajorMapper {
     void updateMajor(Major major);
     // 删除专业
     void deleteMajor(Integer majorId);
+    //resultMap方式查询
+    Major getMajorMapById(Integer majorId);
+    List<Major> getMajorMapAll();
 }

grademanagement-MyBatisProject/src/com/ssm/mapper/MajorMapper.xml

@@ -27,4 +27,20 @@
     <delete id="deleteMajor" parameterType="Integer">
         DELETE FROM major WHERE major_id = #{majorId}
     </delete>
+    <!-- resultMap映射 -->
+    <resultMap type="com.ssm.entity.Major" id="MajorResult">
+        <id property="majorId" column="major_id"/>
+        <result property="majorName" column="major_name"/>
+        <result property="majorCode" column="major_code"/>
+        <result property="deptId" column="dept_id"/>
+        <result property="studyYear" column="study_year"/>
+    </resultMap>
+    <!-- 按ID查询（使用resultMap） -->
+    <select id="getMajorMapById" resultMap="MajorResult" parameterType="Integer">
+        SELECT * FROM major WHERE major_id = #{majorId}
+    </select>
+    <!-- 查询所有（使用resultMap） -->
+    <select id="getMajorMapAll" resultMap="MajorResult">
+        SELECT * FROM major
+    </select>
 </mapper>

grademanagement-MyBatisProject/src/com/ssm/mapper/NoticeMapper.java

@@ -1,4 +1,5 @@
 package com.ssm.mapper;
+import com.ssm.entity.Department;
 import com.ssm.entity.Notice;
 import java.util.List;
 
@@ -11,4 +12,7 @@ public interface NoticeMapper {
     void updateNotice(Notice notice);
     // 删除公告
     void deleteNotice(Integer noticeId);
+    //resultMap方式查询
+    Notice getNoticeMapById(Integer noticeId);
+    List<Notice> getNoticeMapAll();
 }

grademanagement-MyBatisProject/src/com/ssm/mapper/NoticeMapper.xml

@@ -28,4 +28,21 @@
     <delete id="deleteNotice" parameterType="Integer">
         DELETE FROM notice WHERE notice_id = #{noticeId}
     </delete>
+    <!-- resultMap映射 -->
+    <resultMap type="com.ssm.entity.Notice" id="NoticeResult">
+        <id property="noticeId" column="notice_id"/>
+        <result property="title" column="title"/>
+        <result property="content" column="content"/>
+        <result property="publishTime" column="publish_time"/>
+        <result property="publisher" column="publisher"/>
+        <result property="status" column="status"/>
+    </resultMap>
+    <!-- 按ID查询（使用resultMap） -->
+    <select id="getNoticeMapById" resultMap="NoticeResult" parameterType="Integer">
+        SELECT * FROM notice WHERE notice_id = #{noticeId}
+    </select>
+    <!-- 查询所有（使用resultMap） -->
+    <select id="getNoticeMapAll" resultMap="NoticeResult">
+        SELECT * FROM notice
+    </select>
 </mapper>

grademanagement-MyBatisProject/src/com/ssm/mapper/StudentMapper.java

@@ -1,4 +1,5 @@
 package com.ssm.mapper;
+import com.ssm.entity.Department;
 import com.ssm.entity.Student;
 import java.util.List;
 
@@ -11,4 +12,7 @@ public interface StudentMapper {
     void updateStudent(Student student);
     // 删除学生
     void deleteStudent(Integer studentId);
+    //resultMap方式查询
+    Student getStudentMapById(Integer studentId);
+    List<Student> getStudentMapAll();
 }

grademanagement-MyBatisProject/src/com/ssm/mapper/StudentMapper.xml

@@ -29,4 +29,22 @@
     <delete id="deleteStudent" parameterType="Integer">
         DELETE FROM student WHERE student_id = #{studentId}
     </delete>
+    <!-- resultMap映射 -->
+    <resultMap type="com.ssm.entity.Student" id="StudentResult">
+        <id property="studentId" column="student_id"/>
+        <result property="studentNo" column="student_no"/>
+        <result property="studentName" column="student_name"/>
+        <result property="gender" column="gender"/>
+        <result property="age" column="age"/>
+        <result property="classId" column="class_id"/>
+        <result property="phone" column="phone"/>
+    </resultMap>
+    <!-- 按ID查询（使用resultMap） -->
+    <select id="getStudentMapById" resultMap="StudentResult" parameterType="Integer">
+        SELECT * FROM student WHERE student_id = #{studentId}
+    </select>
+    <!-- 查询所有（使用resultMap） -->
+    <select id="getStudentMapAll" resultMap="StudentResult">
+        SELECT * FROM student
+    </select>
 </mapper>

grademanagement-MyBatisProject/src/com/ssm/test/TestMyBatisQueryResultMap.java

@@ -0,0 +1,83 @@
+package com.ssm.test;
+
+import com.ssm.entity.Department;
+import com.ssm.entity.Major;
+import com.ssm.entity.Student;
+import com.ssm.entity.Notice;
+import com.ssm.mapper.DepartmentMapper;
+import com.ssm.mapper.MajorMapper;
+import com.ssm.mapper.StudentMapper;
+import com.ssm.mapper.NoticeMapper;
+import org.apache.ibatis.io.Resources;
+import org.apache.ibatis.session.SqlSession;
+import org.apache.ibatis.session.SqlSessionFactory;
+import org.apache.ibatis.session.SqlSessionFactoryBuilder;
+
+import java.io.Reader;
+import java.util.List;
+
+public class TestMyBatisQueryResultMap {
+    public static void main(String[] args) throws Exception {
+        // 加载配置文件
+        Reader reader = Resources.getResourceAsReader("config.xml");
+        SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(reader);
+        SqlSession sqlSession = factory.openSession();
+
+        // 四个模块 resultMap 查询测试
+        testDeptResultMap(sqlSession);
+        testMajorResultMap(sqlSession);
+        testStudentResultMap(sqlSession);
+        testNoticeResultMap(sqlSession);
+
+        sqlSession.close();
+        reader.close();
+    }
+
+    // 院系 resultMap 查询
+    private static void testDeptResultMap(SqlSession sqlSession) {
+        DepartmentMapper mapper = sqlSession.getMapper(DepartmentMapper.class);
+        Department dept = mapper.getDepartmentMapById(1);
+        System.out.println("===== 院系 resultMap 按ID查询 =====");
+        System.out.println(dept);
+
+        List<Department> deptList = mapper.getDepartmentMapAll();
+        System.out.println("\n===== 院系 resultMap 查询所有 =====");
+        deptList.forEach(System.out::println);
+    }
+
+    // 专业 resultMap 查询
+    private static void testMajorResultMap(SqlSession sqlSession) {
+        MajorMapper mapper = sqlSession.getMapper(MajorMapper.class);
+        Major major = mapper.getMajorMapById(1);
+        System.out.println("\n===== 专业 resultMap 按ID查询 =====");
+        System.out.println(major);
+
+        List<Major> majorList = mapper.getMajorMapAll();
+        System.out.println("\n===== 专业 resultMap 查询所有 =====");
+        majorList.forEach(System.out::println);
+    }
+
+    // 学生 resultMap 查询
+    private static void testStudentResultMap(SqlSession sqlSession) {
+        StudentMapper mapper = sqlSession.getMapper(StudentMapper.class);
+        Student student = mapper.getStudentMapById(1);
+        System.out.println("\n===== 学生 resultMap 按ID查询 =====");
+        System.out.println(student);
+
+        List<Student> studentList = mapper.getStudentMapAll();
+        System.out.println("\n===== 学生 resultMap 查询所有 =====");
+        studentList.forEach(System.out::println);
+    }
+
+    // 公告 resultMap 查询
+    private static void testNoticeResultMap(SqlSession sqlSession) {
+        NoticeMapper mapper = sqlSession.getMapper(NoticeMapper.class);
+        Notice notice = mapper.getNoticeMapById(1);
+        System.out.println("\n===== 公告 resultMap 按ID查询 =====");
+        System.out.println(notice);
+
+        List<Notice> noticeList = mapper.getNoticeMapAll();
+        System.out.println("\n===== 公告 resultMap 查询所有 =====");
+        noticeList.forEach(System.out::println);
+    }
+}

grademanagement-MyBatisProject/src/config.xml

@@ -3,6 +3,8 @@
         PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
         "http://mybatis.org/dtd/mybatis-3-config.dtd">
 <configuration>
+    <!--加载db.properties配置文件 -->
+    <properties resource="db.properties"/>
     <!-- 开启驼峰命名映射 -->
     <settings>
         <setting name="mapUnderscoreToCamelCase" value="true"/>
@@ -12,10 +14,10 @@
         <environment id="development">
             <transactionManager type="JDBC"/>
             <dataSource type="POOLED">
-                <property name="driver" value="com.mysql.cj.jdbc.Driver"/>
-                <property name="url" value="jdbc:mysql://localhost:3306/ssm_score_sys?serverTimezone=Asia/Shanghai&amp;characterEncoding=utf8&amp;useSSL=false"/>
-                <property name="username" value="root"/>
-                <property name="password" value="123456"/>
+                <property name="driver" value="${driver}"/>
+                <property name="url" value="${url}"/>
+                <property name="username" value="${user}"/>
+                <property name="password" value="${password}"/>
             </dataSource>
         </environment>
     </environments>

grademanagement-MyBatisProject/src/db.properties

@@ -0,0 +1,4 @@
+driver=com.mysql.cj.jdbc.Driver
+url=jdbc:mysql://localhost:3306/ssm_score_sys?serverTimezone=Asia/Shanghai&useSSL=false&allowPublicKeyRetrieval=true
+user=root
+password=123456