# mybatis

**Repository Path**: abb930507/mybatis

## Basic Information

- **Project Name**: mybatis
- **Description**: mybatis 练习
- **Primary Language**: Java
- **License**: Apache-2.0
- **Default Branch**: master
- **Homepage**: None
- **GVP Project**: No

## Statistics

- **Stars**: 0
- **Forks**: 0
- **Created**: 2018-08-03
- **Last Updated**: 2020-12-18

## Categories & Tags

**Categories**: Uncategorized

**Tags**: None

## README

## Hello Mybatis

### mybatis启动

[操作session的工具类](../src/main/java/priv/mill/util/MybatisUtil.java)
- SqlSession代表和数据库的一次会话；用完必须关闭；
- SqlSession和connection一样她都是非线程安全。每次使用都应该去获取新的对象。
```
SqlSession openSession = null;
try {
	String resource = "mybatis-config.xml";
	InputStream inputStream = Resources.getResourceAsStream(resource);
	SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
	openSession = sqlSessionFactory.openSession();
	HelloMapper mapper = openSession.getMapper(HelloMapper.class);
	User user = mapper.getUser(1);
	System.out.println(user);
} finally {
	if(openSession!=null)
	openSession.close();
}
```

### 配置数据源
[资源文件](../src/main/resources/jdbc.properties)
[配置文件](../src/main/resources/mybatis-config.xml)

1. 引入类路径下的资源
```
<properties resource="jdbc.properties"></properties>
```
2. 配置数据源
```
<environments default="development">
	<environment id="development">
		<transactionManager type="JDBC" />
		<dataSource type="POOLED">
			<property name="driver" value="${driver}" />
			<property name="url" value="${url}" />
			<property name="username" value="${username}" />
			<property name="password" value="${password}" />
		</dataSource>
	</environment>
</environments>
```
3. 配置mapper
```
<mappers>
	<mapper resource="Mapper/UserMapper.xml" />
</mappers>
```

### 配置mapper文件
[dao文件](../src/main/java/priv/mill/mybatis/dao/HelloMapper.java)
[mapper映射文件](../src/main/resources/Mapper/UserMapper.xml)

> 接口式编程可以做参数的类型检查，更有利于编码的严谨性