第一个Mybatis程序

Mybatis(iBatis)

1. 添加依赖

   <dependencies>
           <dependency>
               <groupId>mysql</groupId>
               <artifactId>mysql-connector-java</artifactId>
               <version>8.0.23</version>
           </dependency>
           <dependency>
               <groupId>org.mybatis</groupId>
               <artifactId>mybatis</artifactId>
               <version>3.5.6</version>
           </dependency>
           <dependency>
               <groupId>junit</groupId>
               <artifactId>junit</artifactId>
               <version>4.11</version>
               <scope>test</scope>
           </dependency>
       </dependencies>
   

2. config核心配置文件

   <configuration>
   
       <environments default="development">
           <environment id="development">
               <transactionManager type="JDBC"/>
               <dataSource type="POOLED">
                   <property name="driver" value="com.mysql.jdbc.Driver"/>
                   <property name="url" value="jdbc:mysql://localhost:3306/mybatis?useSSL=true&amp;useUnicode=true&amp;characterEncoding=UTF-8"/>
                   <property name="username" value="root"/>
                   <property name="password" value="123456"/>
               </dataSource>
           </environment>
       </environments>
   
   </configuration>
   

3. 编写工具类

   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 org.apache.ibatis.session.SqlSessionManager;
   
   import java.io.IOException;
   import java.io.InputStream;
   
   public class MybatisUtils {
   
       private static SqlSessionFactory sqlSessionFactory
       static {
           try{
               String resource="config.xml";
               InputStream inputStream= Resources.getResourceAsStream(resource);
               sqlSessionFactory=new SqlSessionFactoryBuilder().build(inputStream);
           }catch (IOException e){
               e.printStackTrace();
           }
       }
   
       public static SqlSession getSqlSession(){
           SqlSession sqlSession = sqlSessionFactory.openSession();
           return sqlSession;
       }
   
   }
   

4. 创建实体类

   public class User {
       private int id;
       private String name;
       private String pwd;
   
       public User() {
       }
   
       public User(int id, String name, String pwd) {
           this.id = id;
           this.name = name;
           this.pwd = pwd;
       }
   
       public int getId() {
           return id;
       }
   
       public void setId(int id) {
           this.id = id;
       }
   
       public String getName() {
           return name;
       }
   
       public void setName(String name) {
           this.name = name;
       }
   
       public String getPwd() {
           return pwd;
       }
   
       public void setPwd(String pwd) {
           this.pwd = pwd;
       }
   
       @Override
       public String toString() {
           return "User{" +
                   "id=" + id +
                   ", name='" + name + '\'' +
                   ", pwd='" + pwd + '\'' +
                   '}';
       }
   }
   

5. 创建接口

   public interface UserDao {
       List<User> getUserList();
   }
   

6. 编写Mapper.xml

   <?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.muchen.dao.UserDao">
       <select id="getUserList" resultType="com.muchen.pojo.User"></select>
   </mapper>
   

7. 测试

   import com.muchen.pojo.User;
   import com.muchen.utils.MybatisUtils;
   import org.apache.ibatis.session.SqlSession;
   import org.junit.Test;
   import java.util.List;
   
   public class UserDaoTest {
       @Test
       public void test() {
           //第一步：获得SqlSession对象
           SqlSession sqlSession = MybatisUtils.getSqlSession();
           //方式一：getMapper
           UserDao userDao = sqlSession.getMapper(UserDao.class);
           List<User> userList = userDao.getUserList();
           for (User user : userList) {
               System.out.println(user);
           }
           //关闭SqlSession
           sqlSession.close();
       }
   }
   

8. pom中添加mapper文件build

   <build>
           <resources>
               <resource>
                   <directory>src/main/resources</directory>
                   <includes>
                       <include>**/*.properties</include>
                       <include>**/*.xml</include>
                   </includes>
               </resource>
               <resource>
                   <directory>src/main/java</directory>
                   <includes>
                       <include>**/*.properties</include>
                       <include>**/*.xml</include>
                   </includes>
                   <filtering>true</filtering>
               </resource>
           </resources>
       </build>