MyBatis中的properties属性
一、properties属性作用
properties属性提供了一种在启动MyBatis时向它传递属性（替换属性）的方式。
二、具体操作如下
1、编写一个配置文件
db.properties
driver=com.mysql.cj.jdbc.Driver
url=jdbc:mysql://localhost:3306/mybatis?useSSl=true&sueUnicode=true&characterEncoding=UTF-8&serverTimezone=Asia/Shanghai
username=root
password=Wang118821
2、在mybatis-config.xml文件中引入
```java
<configuration>
<properties resource="db.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>
<!-- 每一个Mapper.xml都需要在Mabatis核心配置文件中注册！ -->
<mappers>
<mapper resource="com/example/demo/dao/UserMapper.xml"/>
</mappers>
</configuration>
或是如下：
<configuration>
<properties resource="db.properties">
<property name="username" value="root"/>
<property name="password" value="Wang118821"/>
</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>
<!-- 每一个Mapper.xml都需要在Mabatis核心配置文件中注册！ -->
<mappers>
<mapper resource="com/example/demo/dao/UserMapper.xml"/>
</mappers>
</configuration>