MyBatis配置可以通過傳統的java屬性文件的形式,或者通過<properties>標籤。而通過<properties>標籤,可以使用替代式的變量,而這些變量則是通過資源的引用來進行的。
properties的直接賦值:
<?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="com.mysql.jdbc.Driver" />
<property name="url" value="jdbc:mysql://localhost:3306/mybatis" />
<property name="username" value="root" />
<property name="password" value="88308887" />
</dataSource>
</environment>
</environments>
<mappers>
<!-- <mapper class="net.mybatis.mapper.UserMapper"/> -->
<mapper resource="net/mybatis/mapper/user.mapper.xml"/>
</mappers>
</configuration>
通過變量設置和配置文件引入:
<?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>
<properties resource="jdbc.properties"></properties>
<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 class="net.mybatis.mapper.UserMapper"/> -->
<mapper resource="net/mybatis/mapper/user.mapper.xml"/>
</mappers>
</configuration>
需要注意的是,配置文件的引入是通過<properties>標籤的resources屬性來調用。
MyBatis對於這些的調用有順序,當然前提是這些方式都並存的時候:
首先調用的是config文件中明確的直接賦值的屬性,
之後是通過properties文件引入的屬性,
最後纔是通過SqlSessionFactoryBuilder的方法調用的形式(這種形式基本不用,所以在這裏不涉及)。