1.通过demo来快速入门
1.1环境准备
在pom.xml中添加依赖
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.jay</groupId>
<artifactId>mybatis</artifactId>
<version>1.0-SNAPSHOT</version>
<properties>
<maven.compiler.source>1.8</maven.compiler.source>
<maven.compiler.target>1.8</maven.compiler.target>
</properties>
<dependencies>
<dependency>
<groupId>org.mybatis</groupId>
<artifactId>mybatis</artifactId>
<version>3.4.5</version>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.6</version>
</dependency>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.12</version>
</dependency>
</dependencies>
</project>
1.2全局配置文件
全局配置文件SqlMapConfig.xml
<?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>
<!-- 和Spring整合后environment配置都会被干掉 -->
<environments default="development">
<environment id="development">
<!-- 使用jdbc事务管理,目前由mybatis来管理 -->
<transactionManager type="JDBC" />
<!-- 数据库连接池,目前由mybatis来管理 -->
<dataSource type="POOLED">
<property name="driver" value="com.mysql.jdbc.Driver" />
<property name="url" value="jdbc:mysql://127.0.0.1:3306/mybatisdb?characterEncoding=utf8" />
<property name="username" value="root" />
<property name="password" value="root" />
</dataSource>
</environment>
</environments>
<!--关联映射文件-->
<mappers>
<mapper resource="com/jay/mapper/UserMapper.xml"></mapper>
</mappers>
</configuration>
其中<mappers>用来引入一个或多个映射文件
1.3编写pojo对象
/**
* 为什么id要用Integer类型?因为包装类型: 初始值为null
* 而基本数据类型:本身的值0就是一个状态
*
*/
public class User {
private Integer id;
private String username;
private String password;
private String sex;
private String address;
set、get方法省略...
@Override
public String toString() {
return "User{" +
"id=" + id +
", username='" + username + '\'' +
", password='" + password + '\'' +
", sex='" + sex + '\'' +
", address='" + address + '\'' +
'}';
}
}
1.4编写映射文件
<?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="com.jay.dao.UserDao">
<select id="findAll" resultType="com.jay.domain.User">
select * from user
</select>
</mapper>
上面的属性:
- <select>:执行数据库查询的标签
- id:唯一标识
- resultType:返回结果的类型
1.5测试程序
public class TestCustomFrame {
@Test
public void test(){
//获取配置文件的输入流对象
InputStream inputStream = this.getClass().getClassLoader().getResourceAsStream("SqlMapConfig.xml");
//创建SqlSessionFactoryBuilder对象
SqlSessionFactoryBuilder sqlSessionFactoryBuilder = new SqlSessionFactoryBuilder();
//创建SqlSessionFactory对象
SqlSessionFactory sessionFactory = sqlSessionFactoryBuilder.build(inputStream);
//获取sqlSession对象
SqlSession sqlSession = sessionFactory.openSession();
//执行sql语句
List list = sqlSession.selectList("com.itheima.dao.UserDao.findAll");
//遍历结果集
for (Object o : list) {
System.out.println(o);
}
//关闭资源
sqlSession.close();
}
}