简介
MyBatis是支持定制化SQL、存储过程以及高级映射的优秀的持久层框架，MyBatis避免了几乎所有的JDBC代码和手动设置参数以及获取结果集。MyBatis可以对配置和原生Map使用简单的XML或注解，将接口和Java的POJOs(Plain Old Java Objects,普通的Java对象)映射成数据库中的记录。
简单使用-
我们在数据库里创建一个用户表，然后使用M一把提升来读取表信息,用户表如下
- mybatis依赖
11</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-context</artifactId>
<version>5.2.5.RELEASE</version>
</dependency>
<dependency>
<groupId>org.mybatis</groupId>
<artifactId>mybatis</artifactId>
<version>3.5.1</version>
</dependency>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.11</version>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.9</version>
</dependency>
<!-- https://mvnrepository.com/artifact/org.apache.ibatis/ibatis-core -->
<dependency>
<groupId>org.apache.ibatis</groupId>
<artifactId>ibatis-core</artifactId>
<version>3.0</version>
</dependency>
<dependency>
<groupId>org.aspectj</groupId>
<artifactId>aspectjrt</artifactId>
<version>1.8.9</version>
</dependency>
<!-- http://mvnrepository.com/artifact/org.aspectj/aspectjweaver -->
<dependency>
<groupId>org.aspectj</groupId>
<artifactId>aspectjweaver</artifactId>
<version>1.8.9</version>
</dependency>
<!-- http://mvnrepository.com/artifact/cglib/cglib -->
<dependency>
<groupId>cglib</groupId>
<artifactId>cglib</artifactId>
<version>3.2.2</version>
</dependency>
<dependency>
<groupId>org.aspectj</groupId>
<artifactId>aspectjrt</artifactId>
<version>1.8.14</version>
</dependency>
<dependency>
<groupId>org.aspectj</groupId>
<artifactId>aspectjtools</artifactId>
<version>1.8.14</version>
</dependency>
<dependency>
<groupId>org.testng</groupId>
<artifactId>testng</artifactId>
<version>RELEASE</version>
<scope>compile</scope>
</dependency>
</dependencies>
<build>
<pluginManagement><!-- lock down plugins versions to avoid using Maven defaults (may be moved to parent pom) -->
<plugins>
<!-- clean lifecycle, see https://maven.apache.org/ref/current/maven-core/lifecycles.html#clean_Lifecycle -->
<plugin>
<artifactId>maven-clean-plugin</artifactId>
<version>3.1.0</version>
</plugin>
<!-- default lifecycle, jar packaging: see https://maven.apache.org/ref/current/maven-core/default-bindings.html#Plugin_bindings_for_jar_packaging -->
<plugin>
<artifactId>maven-resources-plugin</artifactId>
<version>3.0.2</version>
</plugin>
<plugin>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.8.0</version>
</plugin>
<plugin>
<artifactId>maven-surefire-plugin</artifactId>
<version>2.22.1</version>
</plugin>
<plugin>
<artifactId>maven-jar-plugin</artifactId>
<version>3.0.2</version>
</plugin>
<plugin>
<artifactId>maven-install-plugin</artifactId>
<version>2.5.2</version>
</plugin>
<plugin>
<artifactId>maven-deploy-plugin</artifactId>
<version>2.8.2</version>
</plugin>
<!-- site lifecycle, see https://maven.apache.org/ref/current/maven-core/lifecycles.html#site_Lifecycle -->
<plugin>
<artifactId>maven-site-plugin</artifactId>
<version>3.7.1</version>
</plugin>
<plugin>
<artifactId>maven-project-info-reports-plugin</artifactId>
<version>3.0.0</version>
</plugin>
</plugins>
</pluginManagement>
<resources>
<resource>
<directory>${basedir}/src/main/java</directory>
<includes>
<include>**/*.xml</include>
</includes>
</resource>
</resources>
</build>
- Mybatis的主配置文件
<?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>
<settings>
<!--setting控制Mybatis全局行为的，设置输出日志-->
<setting name="logImpl" value="STDOUT_LOGGING"/>
</settings>
<environments default="mybatis">
<!--id是唯一值-->
<environment id="mybatis">
<!--mybatis的事务类型-->
<transactionManager type="JDBC"/>
<!--数据源-->
<dataSource type="POOLED">
<property name="driver" value="com.mysql.jdbc.Driver"/>
<property name="url" value="jdbc:mysql://localhost:3306/mybatis?useUnicode=true&characterEncoding=UTF-8"/>
<property name="username" value="root"/>
<property name="password" value="123456"/>
</dataSource>
</environment>
</environments>
<mappers>
<mapper resource="mapper/UserMapper.xml"/>
</mappers>
</configuration>
- 创建用户表的Bean
public class User {
private String username;
private String password;
private String sex;
public User(String username, String password, String sex) {
this.username = username;
this.password = password;
this.sex = sex;
}
public User() {
}
@Override
public String toString() {
return "User{" +
"username='" + username + '\'' +
", password='" + password + '\'' +
", sex='" + sex + '\'' +
'}';
}
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
public String getSex() {
return sex;
}
public void setSex(String sex) {
this.sex = sex;
}
}
- 创建读取数据的mapper接口
import bean.User;
import java.util.List;
public interface UserMapper {
List<User> selectAll();
}
- mapper配置文件
<?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="mapper.UserMapper">
<!--
select表时查询操作。
id:你要执行的sql语句的唯一表示，mybatis会使用这个id的值找到要执行的sql语句
可以自定义，但是要求使用方法名
resultType表示结果类型
-->
<select id="selectAll" resultType="bean.User">
select *
from user
</select>
</mapper>
- 编写一个工具类
package util;
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.IOException;
import java.io.Reader;
public class MybatisUtils {
private static SqlSessionFactory factory = null;
static {
//mybatis主配置文件的位置
String config = "mybatis.xml";
try {
//读取config表示的文件
Reader reader = Resources.getResourceAsReader(config);
//创建SqlSessionFactory对象
factory = new SqlSessionFactoryBuilder().build(reader);
} catch (IOException e) {
e.printStackTrace();
}
}
//获取SqlSession
public static SqlSession getSqlSession() {
SqlSession session = null;
if (factory != null) {
session = factory.openSession();
}
return session;
}
}
- 编写Dao
import bean.User;
import mapper.UserMapper;
import org.apache.ibatis.session.SqlSession;
import util.MybatisUtils;
import java.util.List;
public class UserDao implements UserMapper {
@Override
public List<User> selectAll() {
//使用Mybatis工厂创建SqlSession对象，这样的优势是解耦
SqlSession session = MybatisUtils.getSqlSession();
//这个id和mapper接口的方法名一样
String sql = "selectAll";
List<User> userList = session.selectList(sql);
session.close();
return userList;
}
}
- 测试
import Dao.UserDao;
import bean.User;
import org.junit.Test;
import java.util.List;
public class AppTest {
@Test
public void selectAll(){
UserDao userDao = new UserDao();
List<User>userList = userDao.selectAll();
for (User user:userList){
System.out.println(user);
}
}
}
-
结果
