MyBatis - 快速开始
大约 3 分钟
MyBatis - 快速开始
1. 添加依赖
<dependencies>
<dependency>
<groupId>org.mybatis</groupId>
<artifactId>mybatis</artifactId>
</dependency>
<dependency>
<groupId>com.github.pagehelper</groupId>
<artifactId>pagehelper</artifactId>
</dependency>
<dependency>
<groupId>tk.mybatis</groupId>
<artifactId>mapper</artifactId>
</dependency>
<dependency>
<groupId>org.mybatis.caches</groupId>
<artifactId>mybatis-redis</artifactId>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<scope>runtime</scope>
</dependency>
<dependency>
<groupId>org.junit.jupiter</groupId>
<artifactId>junit-jupiter-api</artifactId>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<scope>provided</scope>
</dependency>
</dependencies>
2. 配置文件
<?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>
<!--
1.属性
https://mybatis.org/mybatis-3/zh/configuration.html#properties
-->
<properties resource="jdbc.properties"/>
<!--
2.设置
https://mybatis.org/mybatis-3/zh/configuration.html#settings
-->
<settings>
<!-- 开启二级缓存 -->
<setting name="cacheEnabled" value="true"/>
</settings>
<!--
3.类型别名
https://mybatis.org/mybatis-3/zh/configuration.html#typeAliases
-->
<typeAliases>
<typeAlias type="com.spectred.demo.mybatis.entity.User" alias="user"/>
</typeAliases>
<!--
4.类型处理器
https://mybatis.org/mybatis-3/zh/configuration.html#typeHandlers
-->
<typeHandlers>
</typeHandlers>
<!--
5.对象工厂
https://mybatis.org/mybatis-3/zh/configuration.html#objectFactory
<objectFactory type="">
</objectFactory>
-->
<!--
5.插件
https://mybatis.org/mybatis-3/zh/configuration.html#objectFactory
-->
<plugins>
<!-- 分页插件 -->
<plugin interceptor="com.github.pagehelper.PageInterceptor">
<property name="dialect" value="com.github.pagehelper.dialect.helper.MySqlDialect"/>
</plugin>
</plugins>
<!--
6.环境配置
https://mybatis.org/mybatis-3/zh/configuration.html#environments
-->
<environments default="development">
<environment id="development">
<transactionManager type="JDBC"></transactionManager>
<dataSource type="POOLED">
<property name="driver" value="${jdbc.driver}"/>
<property name="url" value="${jdbc.url}"/>
<property name="username" value="${jdbc.username}"/>
<property name="password" value="${jdbc.password}"/>
</dataSource>
</environment>
</environments>
<!--
7.数据库厂商标识
https://mybatis.org/mybatis-3/zh/configuration.html#databaseIdProvider
-->
<databaseIdProvider type="DB_VENDOR"></databaseIdProvider>
<!--
8.映射器
https://mybatis.org/mybatis-3/zh/configuration.html#mappers
-->
<mappers>
<!-- 使用相对于类路径的资源引用 -->
<mapper resource="com/spectred/mappers/UserMapper.xml"/>
</mappers>
</configuration>
3. 数据库脚本，实体类，DAO接口，MapperXML文件
create table user
(
id int not null primary key,
username varchar(32) null
)
comment '用户表';
import lombok.Data;
@Data
public class User {
private Integer id;
private String username;
}
import java.util.List;
public interface IUserMapper {
User selectById(Integer id);
List<User> selectAll();
int insert(User user);
int updateById(User user);
}
<?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.spectred.demo.mybatis.mappers.IUserMapper">
<select id="selectById" parameterType="int" resultType="user">
SELECT *
FROM user
WHERE id = #{id}
</select>
<select id="selectAll" resultType="com.spectred.demo.mybatis.entity.User">
SELECT *
FROM user
</select>
<insert id="insert" parameterType="user">
INSERT INTO user (id, username)
VALUES (#{id}, #{username})
</insert>
<update id="updateById" parameterType="user">
UPDATE user
SET username = #{username}
WHERE id = #{id}
</update>
</mapper>
4. 基于XML的增删改查
import com.spectred.demo.mybatis.entity.User;
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.junit.jupiter.api.AfterEach;
import org.junit.jupiter.api.Assertions;
import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;
import java.io.InputStream;
import java.util.List;
public class CrudByXMLTest {
private SqlSession sqlSession;
@BeforeEach
public void before() throws Exception {
InputStream inputStream = Resources.getResourceAsStream("mybatis-config.xml");
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
sqlSession = sqlSessionFactory.openSession();
}
@Test
public void test_select() {
User user = sqlSession.selectOne("com.spectred.demo.mybatis.mappers.IUserMapper.selectById", 2);
Assertions.assertSame(2, user.getId());
}
@Test
public void test_selectAll() {
List<User> usersList = sqlSession.selectList("com.spectred.demo.mybatis.mappers.IUserMapper.selectAll");
Assertions.assertNotEquals(0, usersList.size());
}
@Test
public void test_insert() {
User user = new User();
user.setId(5);
user.setUsername("Jack");
int row = sqlSession.insert("com.spectred.demo.mybatis.mappers.IUserMapper.insert", user);
sqlSession.commit();
Assertions.assertSame(1, row);
}
@Test
public void test_update() {
User user = new User();
user.setId(1);
user.setUsername("Java");
int row = sqlSession.update("com.spectred.demo.mybatis.mappers.IUserMapper.updateById", user);
sqlSession.commit();
Assertions.assertSame(1, row);
}
@AfterEach
public void after() {
System.out.println("---- 执行结果 ----");
List<User> usersList = sqlSession.selectList("com.spectred.demo.mybatis.mappers.IUserMapper.selectAll");
usersList.forEach(System.out::println);
sqlSession.close();
}
}
5. 基于Mapper的增删改查
import com.spectred.demo.mybatis.entity.User;
import com.spectred.demo.mybatis.mappers.IUserMapper;
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.junit.jupiter.api.AfterEach;
import org.junit.jupiter.api.Assertions;
import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;
import java.io.InputStream;
import java.util.List;
/**
* @author spectred
*/
public class CrudByMapperTest {
private SqlSession sqlSession;
@BeforeEach
public void before() throws Exception {
InputStream inputStream = Resources.getResourceAsStream("mybatis-config.xml");
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
sqlSession = sqlSessionFactory.openSession();
}
@Test
public void test_select() {
IUserMapper userMapper = sqlSession.getMapper(IUserMapper.class);
User user = userMapper.selectById(1);
Assertions.assertSame(1, user.getId());
}
@Test
public void test_selectAll() {
IUserMapper userMapper = sqlSession.getMapper(IUserMapper.class);
List<User> usersList = userMapper.selectAll();
Assertions.assertNotEquals(0, usersList.size());
}
@Test
public void test_insert() {
User user = new User();
user.setId(5);
user.setUsername("Jack");
IUserMapper userMapper = sqlSession.getMapper(IUserMapper.class);
int row = userMapper.insert(user);
sqlSession.commit();
Assertions.assertSame(1, row);
}
@Test
public void test_update() {
User user = new User();
user.setId(1);
user.setUsername("Java");
IUserMapper userMapper = sqlSession.getMapper(IUserMapper.class);
int row = userMapper.updateById(user);
sqlSession.commit();
Assertions.assertSame(1, row);
}
@AfterEach
public void after() {
sqlSession.close();
}
}
6. 基于注解的增删改查
@Select("SELECT * FROM user WHERE username = #{username}")
List<User> selectByName(@Param("username") String username);
@Insert("INSERT INTO user (id,username) VALUES (#{id},#{username})")
int insertV2 (User user);
@Delete("DELETE FROM user WHERE id = #{id}")
int deleteById(@Param("id") Integer id);
import com.spectred.demo.mybatis.entity.User;
import com.spectred.demo.mybatis.mappers.IUserMapper;
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.junit.jupiter.api.AfterEach;
import org.junit.jupiter.api.Assertions;
import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;
import java.io.InputStream;
import java.util.List;
public class CrudByAnnotationTest {
private SqlSession sqlSession;
private IUserMapper userMapper;
@BeforeEach
public void before() throws Exception {
InputStream inputStream = Resources.getResourceAsStream("mybatis-config.xml");
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
sqlSession = sqlSessionFactory.openSession();
userMapper = sqlSession.getMapper(IUserMapper.class);
}
@Test
public void test_selectByName() {
List<User> users = userMapper.selectByName("Jack");
users.forEach(System.out::println);
Assertions.assertNotEquals(0, users.size());
}
@Test
public void test_insertV2() {
User user = new User();
user.setId(7);
user.setUsername("Tom");
int row = userMapper.insertV2(user);
sqlSession.commit();
Assertions.assertEquals(1, row);
}
@Test
public void test_deleteById() {
int row = userMapper.deleteById(7);
sqlSession.commit();
Assertions.assertEquals(1, row);
}
@AfterEach
public void after() {
sqlSession.close();
}
}