MyBatis核心SqlSessionFactory的创建

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　　SqlSessionFactory是每个MyBatis应用的核心
　　其实现方式有两种，使用配置文件或使用JAVA编码。
　　1.配置文件实现
　　


<?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>
<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>
<mappers>
<mapper resource="org/mybatis/example/BlogMapper.xml" />
</mappers>
</configuration>
　　使用时利用下面代码进行初始化
　　


String resource = "org/mybatis/example/Configuration.xml";
Reader reader = Resources.getResourceAsReader(resource);
SqlSessionFactory　sqlMapper = new SqlSessionFactoryBuilder().build(reader);
 　　2.使用编码实现
　　


DataSource dataSource = new PooledDataSource("com.mysql.jdbc.Driver",
"jdbc:mysql://localhost/mybatis?userUnicode=true&amp;characterEncoding=utf8", "admin", "123456");
Environment environment = new Environment("test", new JdbcTransactionFactory(), dataSource);
Configuration configuration = new Configuration(environment);
configuration.addMapper(TestDao.class);
 SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(configuration);
　　生命同期问题
　　SqlSessionFactoryBuilder　是用过即丢，其生命周期只存在于方法体内
　　SqlSessionFactory　单例，存在于整合应用运行时