Mybatis环境配置类Environment
在初始化Mybatis框架时,需要配置environment元素,该元素允许有多个,方便我们在不同环境下切换后端的存储。拥有一个id属性用于该环境,此id必须唯一,否则后续配置会覆盖前面的配置,该元素拥有两个子元素(事务管理器),(数据源),这两个元素后续会进行讲解,目前只需要记住名称即可。如下便是的相关配置,该配置定义了dev,test,prod三种环境
<configuration>
<!--引入外部资源 -->
<properties resource="./mybatis-mysql.properties">
</properties>
<settings>
<setting name="cacheEnabled" value="true"/>
</settings>
<objectFactory type="com.zzz.mybatis.object.MyObjectFacotry">
<property name="env" value="test"/>
</objectFactory>
<!--设置默认的环境为开发环境 -->
<environments default="development">
<environment id="development">
<transactionManager type="JDBC"/>
<dataSource type="UNPOOLED">
<property name="driver" value="${dev.driver}"/>
<property name="url" value="${dev.url}"/>
<property name="username" value="${dev.username}"/>
<property name="password" value="${dev.password}"/>
</dataSource>
</environment>
<!--测试环境用 -->
<environment id="test">
<transactionManager type="JDBC"/>
<dataSource type="POOLED">
<property name="driver" value="${test.driver}"/>
<property name="url" value="${test.url}"/>
<property name="username" value="${test.username}"/>
<property name="password" value="${test.password}"/>
</dataSource>
</environment>
<!--生产环境用 -->
<environment id="prod">
<transactionManager type="MANAGED"/>
<dataSource type="JDBC">
<property name="driver" value="${prod.driver}"/>
<property name="url" value="${prod.url}"/>
<property name="username" value="${prod.username}"/>
<property name="password" value="${prod.password}"/>
</dataSource>
</environment>
</environments>
</configuration>
mybatis-config.xml
dev.driver=com.mysql.jdbc.Driver dev.url=jdbc:mysql://localhost:3306/test?useSSL=false&serverTimezone=UTC dev.username=root dev.password=root test.driver=com.mysql.jdbc.Driver test.url=jdbc:mysql://localhost:3306/test?useSSL=false&serverTimezone=UTC test.username=root test.password=root prod.driver=com.mysql.jdbc.Driver prod.url=jdbc:mysql://localhost:3306/test?useSSL=false&serverTimezone=UTC prod.username=root prod.password=root
与之对应的Java类为org.apache.ibatis.mapping.Environment,该类同样拥有三个属性与xml元素对应,如下代码
private final String id; private final TransactionFactory transactionFactory;//事务工厂 private final DataSource dataSource;//数据源
创建一个Environment
Environment的创建可以通过构造器方式和建造器方式,Environment类中有一个内在的静态类Builder，Builder类提供了一个builder方法对Environment进行构建。代码如下
方式一
1 @Test 2 public void TestgetInstanceEnviroment() throws SQLException { 3 //设置mysql数据源 4 MysqlConnectionPoolDataSource dataSource=new MysqlConnectionPoolDataSource(); 5 dataSource.setUser("root"); 6 dataSource.setPassword("root"); 7 dataSource.setUrl("jdbc:mysql://localhost:3306/test?useSSL=false&serverTimezone=UTC"); 8 //设置事务工厂 9 TransactionFactory transactionFactory= new JdbcTransactionFactory(); 10 //实例化id 11 Environment environment = new Environment("test", transactionFactory, dataSource); 12 System.out.println(environment.getId()+environment.getDataSource().toString()+environment.getTransactionFactory().toString()); 13 14 }
方式二
1 @Test 2 public void TestgetInstanceEnviromentByBuilder() throws SQLException { 3 Environment environment = new Environment.Builder("prod") 4 .transactionFactory(new JdbcTransactionFactory()) 5 .dataSource(new MysqlConnectionPoolDataSource() 6 {{ 7 setUser("root"); 8 setPassword("root"); 9 setUrl("jdbc:mysql://localhost:3306/test?useSSL=false&serverTimezone=UTC"); 10 } 11 }) 12 .build(); 13 System.out.println(environment.getId()+environment.getDataSource().toString()+environment.getTransactionFactory().toString()); 14 15 16 17 }
应用Enviroment
1 @Test 2 public void TestSqlsessionFactoryBuilder() throws SQLException { 3 4 SqlSessionFactoryBuilder factoryBuilder = new SqlSessionFactoryBuilder(); 5 InputStream inputStream = getClass().getResourceAsStream("/mybatis-config.xml"); 6 SqlSessionFactoryBuilder builder = new SqlSessionFactoryBuilder(); 7 SqlSessionFactory sessionFactory=builder.build(inputStream); 8 SqlSession session=sessionFactory.openSession(); 9 Environment environment=session.getConfiguration().getEnvironment(); 10 System.out.println(environment.getId()+environment.getDataSource().toString()+environment.getTransactionFactory().toString()); 11 environment = new Environment.Builder("other") 12 .transactionFactory(new JdbcTransactionFactory()) 13 .dataSource(new MysqlConnectionPoolDataSource() 14 {{ 15 setUser("mytest"); 16 setPassword("mytest"); 17 setUrl("jdbc:mysql://localhost:3306/test?useSSL=false&serverTimezone=UTC"); 18 } 19 }) 20 .build(); 21 session.getConfiguration().setEnvironment(environment); 22 System.out.println(environment.getId()+environment.getDataSource().toString()+environment.getTransactionFactory().toString()); 23 24 }
development org.apache.ibatis.datasource.unpooled.UnpooledDataSource@7a5d012corg.apache.ibatis.transaction.jdbc.JdbcTransactionFactory@3fb6a447
other com.zzz.mybatis.service.EnviromentTest$2@6be46e8forg.apache.ibatis.transaction.jdbc.JdbcTransactionFactory@3567135c