Finish configuring mybatis-plus

In this commit, we add the `mybatis-plus` dependency to the `pom.xml`
file, and configure the `mybatis-plus` in the `application-dev.yml`
file. We also add the `UserMapper` interface and `UserPO` class to the
project for testing. The `UserMapper` interface is used to define the
database operations (the real operations will generated by
`mybatis-plus`), and the `UserPO` class is used to define the user
entity. We use `spring-boot-test` to test this function (I've add one
item in the `t_user` table).

This solved #28.

pom.xml

@@ -108,6 +108,11 @@
             <groupId>org.springframework.boot</groupId>
             <artifactId>spring-boot-starter-jdbc</artifactId>
         </dependency>
+        <dependency>
+            <groupId>com.baomidou</groupId>
+            <artifactId>mybatis-plus-spring-boot3-starter</artifactId>
+            <version>3.5.7</version>
+        </dependency>
     </dependencies>
 
     <build>

src/main/java/edu/cmipt/gcs/GcsApplication.java

@@ -1,9 +1,11 @@
 package edu.cmipt.gcs;
 
+import org.mybatis.spring.annotation.MapperScan;
 import org.springframework.boot.SpringApplication;
 import org.springframework.boot.autoconfigure.SpringBootApplication;
 
 @SpringBootApplication
+@MapperScan("edu.cmipt.gcs.dao")
 public class GcsApplication {
 
     public static void main(String[] args) {

src/main/java/edu/cmipt/gcs/dao/UserMapper.java

@@ -0,0 +1,8 @@
+package edu.cmipt.gcs.dao;
+
+import com.baomidou.mybatisplus.core.mapper.BaseMapper;
+
+import edu.cmipt.gcs.pojo.UserPO;
+
+public interface UserMapper extends BaseMapper<UserPO> {
+}

src/main/java/edu/cmipt/gcs/pojo/UserPO.java

@@ -0,0 +1,11 @@
+package edu.cmipt.gcs.pojo;
+
+import java.time.LocalDateTime;
+
+import com.baomidou.mybatisplus.annotation.TableId;
+import com.baomidou.mybatisplus.annotation.TableName;
+
+@TableName("t_user")
+public record UserPO(@TableId Long pkUserId, String username, String email, String userPassword, LocalDateTime gmtCreated,
+        LocalDateTime gmtUpdated, LocalDateTime gmtDeleted) {
+}

src/main/resources/application-dev.yml

@@ -1,4 +1,3 @@
-debug: true
 spring:
   datasource:
     druid:

src/main/resources/application-test.yml

@@ -1,4 +1,3 @@
-debug: true
 spring:
   datasource:
     druid:

src/test/java/edu/cmipt/gcs/controller/dao/UserMapperTest.java

@@ -0,0 +1,27 @@
+package edu.cmipt.gcs.controller.dao;
+
+import java.util.List;
+
+import org.junit.jupiter.api.Test;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.context.SpringBootTest;
+
+import com.baomidou.mybatisplus.core.toolkit.Assert;
+
+import edu.cmipt.gcs.dao.UserMapper;
+import edu.cmipt.gcs.pojo.UserPO;
+
+@SpringBootTest
+public class UserMapperTest {
+
+    @Autowired
+    private UserMapper userMapper;
+
+    @Test
+    public void testSelect() {
+        System.out.println(("----- selectAll method test ------"));
+        List<UserPO> userList = userMapper.selectList(null);
+        Assert.isTrue(1 == userList.size(), "");
+        userList.forEach(System.out::println);
+    }
+}