MyBatis配置数据库连接并实现交互的操作步骤

<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/test"/>
                <property name="username" value="root"/>
                <property name="password" value="123456"/>
            </dataSource>
        </environment>
    </environments>
</configuration>

<dependency>
    <groupId>com.zaxxer</groupId>
    <artifactId>HikariCP</artifactId>
    <version>5.0.1</version>
</dependency>

<dataSource type="com.zaxxer.hikari.HikariDataSource">
    <property name="jdbcUrl" value="jdbc:mysql://localhost:3306/test"/>
    <property name="username" value="root"/>
    <property name="password" value="123456"/>
    <property name="maximumPoolSize" value="20"/> <!-- 关键参数！ -->
</dataSource>

spring:
  datasource:
    url: jdbc:mysql://localhost:3306/test
    username: root
    password: 123456
    driver-class-name: com.mysql.cj.jdbc.Driver
    hikari:
      maximum-pool-size: 20
      connection-timeout: 3000

public class DynamicDataSource extends AbstractRoutingDataSource {
    @Override
    protected Object determineCurrentLookupKey() {
        return DatabaseContextHolder.get(); // 从ThreadLocal获取数据源标识
    }
}

@Bean
public DataSource dynamicDataSource() {
    Map<Object, Object> targetDataSources = new HashMap<>();
    targetDataSources.put("master", masterDataSource());
    targetDataSources.put("slave", slaveDataSource());
    DynamicDataSource ds = new DynamicDataSource();
    ds.setTargetDataSources(targetDataSources);
    ds.setDefaultTargetDataSource(masterDataSource());
    return ds;
}

@GetMapping("/query")
@DataSource("slave") // 自定义注解
public List<User> query() {
    return userMapper.selectAll();
}

try (SqlSession session = sqlSessionFactory.openSession()) {
    UserMapper mapper = session.getMapper(UserMapper.class);
    // ...
} // 自动关闭