MyBatis多數據源的兩種配置方式

2024-07-14 08:43:07

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前言

同一個項目有時會涉及到多個數據庫，也就是多數據源。多數據源又可以分為兩種情況：

1）兩個或多個數據庫沒有相關性，各自獨立，其實這種可以作為兩個項目來開發。比如在游戲開發中一個數據庫是平臺數據庫，其它還有平臺下的游戲對應的數據庫；

2）兩個或多個數據庫是master-slave的關系，比如有mysql搭建一個 master-master，其后又帶有多個slave；或者采用MHA搭建的master-slave復制；

MyBatis多數據源的配置主要有兩種方式:

通過@MapperScan注解，對不同包下的Mapper使用不同的sqlSessionFactory
通過@MapperScan注解加自定義注解，對使用不同注解的Mapper使用不同的sqlSessionFactory

第二種配置相對靈活，示例如下:

package bj;import ch.qos.logback.classic.Level;import ch.qos.logback.classic.Logger;import com.zaxxer.hikari.HikariDataSource;import io.shardingsphere.shardingjdbc.spring.boot.SpringBootConfiguration;import org.apache.ibatis.annotations.Mapper;import org.apache.ibatis.annotations.Select;import org.apache.ibatis.session.SqlSessionFactory;import org.mybatis.spring.SqlSessionFactoryBean;import org.mybatis.spring.annotation.MapperScan;import org.slf4j.LoggerFactory;import org.springframework.boot.SpringApplication;import org.springframework.boot.WebApplicationType;import org.springframework.boot.autoconfigure.SpringBootApplication;import org.springframework.boot.context.event.ApplicationReadyEvent;import org.springframework.context.ApplicationListener;import org.springframework.context.annotation.Bean;import org.springframework.context.annotation.Configuration;import org.springframework.context.annotation.Primary;import org.springframework.jdbc.core.JdbcTemplate;import javax.annotation.Resource;import javax.sql.DataSource;import java.lang.annotation.ElementType;import java.lang.annotation.Retention;import java.lang.annotation.RetentionPolicy;import java.lang.annotation.Target;import java.util.List;import java.util.Map;/** * Created by BaiJiFeiLong@gmail.com at 2018/12/6 下午9:29 * <p> * MyBatis多數據源演示 */@SpringBootApplication(exclude = {SpringBootConfiguration.class})@Configuration@MapperScan(annotationClass = Mapper.class, basePackageClasses = MyBatisApp.class,  sqlSessionFactoryRef = "sqlSessionFactory")public class MyBatisApp implements ApplicationListener<ApplicationReadyEvent> { /**  * SecondaryMapper配置  * /@MapperScan 注解一次只能添加一個，所以需要單獨再加一個配置類  * 自定義@MapperScan會替換MyBatis自動添加的默認@MapperScan。所以主@MapperScan也必須顯式添加  */ @Configuration @MapperScan(annotationClass = SecondaryMapper.class, basePackageClasses = MyBatisApp.class,   sqlSessionFactoryRef = "sqlSessionFactorySecond") static class SecondaryMapperConfiguration { } public static void main(String[] args) {  new SpringApplication(MyBatisApp.class) {{   setWebApplicationType(WebApplicationType.NONE);  }}.run(args); } @Resource private DataSource dataSource; @Resource private DataSource dataSourceSecond; @Resource private JdbcTemplate jdbcTemplate; @Resource private UserMapper userMapper; @Resource private SecondaryUserMapper secondaryUserMapper; private void initLogger() {  ((Logger) LoggerFactory.getLogger(MyBatisApp.class)).setLevel(Level.DEBUG);  ((Logger) LoggerFactory.getLogger(JdbcTemplate.class)).setLevel(Level.DEBUG); } private void initDatabase() {  String oldDatabase = jdbcTemplate.queryForObject("SELECT DATABASE()", String.class);  jdbcTemplate.execute("DROP SCHEMA IF EXISTS one");  jdbcTemplate.execute("CREATE SCHEMA one");  jdbcTemplate.execute("USE one");  jdbcTemplate.execute("CREATE TABLE user(id INT AUTO_INCREMENT PRIMARY KEY, name VARCHAR(32) CHARSET 'utf8')");  jdbcTemplate.execute("INSERT INTO user(name) VALUES ('人民的兒子')");  jdbcTemplate.execute("INSERT INTO user(name) VALUES ('人民的孫子')");  jdbcTemplate.execute("INSERT INTO user(name) VALUES ('人民的曾孫子')");  jdbcTemplate.execute("DROP SCHEMA IF EXISTS two");  jdbcTemplate.execute("CREATE SCHEMA two");  jdbcTemplate.execute("USE two");  jdbcTemplate.execute("CREATE TABLE user(id INT AUTO_INCREMENT PRIMARY KEY, name VARCHAR(32) CHARSET 'utf8')");  jdbcTemplate.execute("INSERT INTO user(name) VALUES ('人民的爹')");  jdbcTemplate.execute("INSERT INTO user(name) VALUES ('人民的爺')");  jdbcTemplate.execute("INSERT INTO user(name) VALUES ('人民的太爺')");  jdbcTemplate.execute("INSERT INTO user(name) VALUES ('人民的老太爺')");  jdbcTemplate.execute("USE " + oldDatabase); } @Override public void onApplicationEvent(ApplicationReadyEvent applicationReadyEvent) {  initLogger();  initDatabase();  System.out.println("Users:");  userMapper.selectAll().forEach(System.out::println);  System.out.println("Secondary users:");  secondaryUserMapper.selectAll().forEach(System.out::println); } /**  * 主數據源  * <p>  * 如果不添加@Primary注解, MyBatis可以工作，但是JdbcTemplate無法注入  *  * @return .  */ @Primary @Bean public DataSource dataSource() {  return new HikariDataSource() {{   setJdbcUrl("jdbc:mysql://localhost/one?useUnicode=true&characterEncoding=utf8");   setUsername("root");   setPassword("root");  }}; } /**  * 副數據源  *  * @return .  */ @Bean public DataSource dataSourceSecond() {  return new HikariDataSource() {{   setJdbcUrl("jdbc:mysql://localhost/two?useUnicode=true&characterEncoding=utf8");   setUsername("root");   setPassword("root");  }}; } /**  * 主SqlSessionFactory。使用主數據源。自定義SqlSessionFactory后，MyBatis就不自動添加SqlSessionFactory了，所以必須有  *  * @return .  * @throws Exception .  */ @Bean public SqlSessionFactory sqlSessionFactory() throws Exception {  return new SqlSessionFactoryBean() {{   setDataSource(dataSource);  }}.getObject(); } /**  * 副SqlSessionFactory。使用副數據源  *  * @return .  * @throws Exception .  */ @Bean public SqlSessionFactory sqlSessionFactorySecond() throws Exception {  return new SqlSessionFactoryBean() {{   setDataSource(dataSourceSecond);  }}.getObject(); } @Mapper interface UserMapper {  @Select("SELECT * FROM user")  List<Map<String, Object>> selectAll(); } @SecondaryMapper interface SecondaryUserMapper {  @Select("SELECT * FROM user")  List<Map<String, Object>> selectAll(); } /**  * 自定義Mapper注解，用于標識使用的數據源  */ @Target(ElementType.TYPE) @Retention(RetentionPolicy.RUNTIME) @interface SecondaryMapper { }}

控制臺輸出:

.   ____          _            __ _ _
/// / ___'_ __ _ _(_)_ __ __ _ / / / /
( ( )/___ | '_ | '_| | '_ // _` | / / / /
/// ___)| |_)| | | | | || (_| | ) ) ) )
' |____| .__|_| |_|_| |_/__, | / / / /
=========|_|==============|___/=/_/_/_/
:: Spring Boot ::        (v2.1.0.RELEASE)

2018-12-07 11:49:02.596 INFO 5154 --- [           main] bj.MyBatisApp                            : Starting MyBatisApp on MacBook-Air-2.local with PID 5154 (/Users/yuchao/temp/java/hellomaven/target/classes started by yuchao in /Users/yuchao/temp/java/hellomaven)
2018-12-07 11:49:02.633 INFO 5154 --- [           main] bj.MyBatisApp                            : No active profile set, falling back to default profiles: default
2018-12-07 11:49:05.341 INFO 5154 --- [           main] com.zaxxer.hikari.HikariDataSource       : HikariPool-1 - Starting...
2018-12-07 11:49:05.499 INFO 5154 --- [           main] com.zaxxer.hikari.HikariDataSource       : HikariPool-1 - Start completed.
2018-12-07 11:49:05.547 INFO 5154 --- [           main] org.quartz.impl.StdSchedulerFactory      : Using default implementation for ThreadExecutor
2018-12-07 11:49:05.569 INFO 5154 --- [           main] org.quartz.core.SchedulerSignalerImpl    : Initialized Scheduler Signaller of type: class org.quartz.core.SchedulerSignalerImpl
2018-12-07 11:49:05.569 INFO 5154 --- [           main] org.quartz.core.QuartzScheduler          : Quartz Scheduler v.2.3.0 created.
2018-12-07 11:49:05.570 INFO 5154 --- [           main] org.quartz.simpl.RAMJobStore             : RAMJobStore initialized.
2018-12-07 11:49:05.571 INFO 5154 --- [           main] org.quartz.core.QuartzScheduler          : Scheduler meta-data: Quartz Scheduler (v2.3.0) 'quartzScheduler' with instanceId 'NON_CLUSTERED'
Scheduler class: 'org.quartz.core.QuartzScheduler' - running locally.
NOT STARTED.
Currently in standby mode.
Number of jobs executed: 0
Using thread pool 'org.quartz.simpl.SimpleThreadPool' - with 10 threads.
Using job-store 'org.quartz.simpl.RAMJobStore' - which does not support persistence. and is not clustered.

2018-12-07 11:49:05.571 INFO 5154 --- [           main] org.quartz.impl.StdSchedulerFactory      : Quartz scheduler 'quartzScheduler' initialized from an externally provided properties instance.
2018-12-07 11:49:05.571 INFO 5154 --- [           main] org.quartz.impl.StdSchedulerFactory      : Quartz scheduler version: 2.3.0
2018-12-07 11:49:05.571 INFO 5154 --- [           main] org.quartz.core.QuartzScheduler          : JobFactory set to: org.springframework.scheduling.quartz.SpringBeanJobFactory@769a58e5
2018-12-07 11:49:05.780 WARN 5154 --- [           main] reactor.netty.tcp.TcpResources           : [http] resources will use the default LoopResources: DefaultLoopResources {prefix=reactor-http, daemon=true, selectCount=4, workerCount=4}
2018-12-07 11:49:05.780 WARN 5154 --- [           main] reactor.netty.tcp.TcpResources           : [http] resources will use the default ConnectionProvider: PooledConnectionProvider {name=http, poolFactory=reactor.netty.resources.ConnectionProvider$$Lambda$284/1788545647@10667848}
2018-12-07 11:49:06.061 INFO 5154 --- [           main] o.s.s.quartz.SchedulerFactoryBean        : Starting Quartz Scheduler now
2018-12-07 11:49:06.062 INFO 5154 --- [           main] org.quartz.core.QuartzScheduler          : Scheduler quartzScheduler_$_NON_CLUSTERED started.
2018-12-07 11:49:06.079 INFO 5154 --- [           main] bj.MyBatisApp                            : Started MyBatisApp in 4.645 seconds (JVM running for 6.354)
2018-12-07 11:49:06.084 DEBUG 5154 --- [           main] o.s.jdbc.core.JdbcTemplate               : Executing SQL query [SELECT DATABASE()]
2018-12-07 11:49:06.105 DEBUG 5154 --- [           main] o.s.jdbc.core.JdbcTemplate               : Executing SQL statement [DROP SCHEMA IF EXISTS one]
2018-12-07 11:49:06.115 DEBUG 5154 --- [           main] o.s.jdbc.core.JdbcTemplate               : Executing SQL statement [CREATE SCHEMA one]
2018-12-07 11:49:06.117 DEBUG 5154 --- [           main] o.s.jdbc.core.JdbcTemplate               : Executing SQL statement [USE one]
2018-12-07 11:49:06.119 DEBUG 5154 --- [           main] o.s.jdbc.core.JdbcTemplate               : Executing SQL statement [CREATE TABLE user(id INT AUTO_INCREMENT PRIMARY KEY, name VARCHAR(32) CHARSET 'utf8')]
2018-12-07 11:49:06.153 DEBUG 5154 --- [           main] o.s.jdbc.core.JdbcTemplate               : Executing SQL statement [INSERT INTO user(name) VALUES ('人民的兒子')]
2018-12-07 11:49:06.157 DEBUG 5154 --- [           main] o.s.jdbc.core.JdbcTemplate               : Executing SQL statement [INSERT INTO user(name) VALUES ('人民的孫子')]
2018-12-07 11:49:06.161 DEBUG 5154 --- [           main] o.s.jdbc.core.JdbcTemplate               : Executing SQL statement [INSERT INTO user(name) VALUES ('人民的曾孫子')]
2018-12-07 11:49:06.164 DEBUG 5154 --- [           main] o.s.jdbc.core.JdbcTemplate               : Executing SQL statement [DROP SCHEMA IF EXISTS two]
2018-12-07 11:49:06.174 DEBUG 5154 --- [           main] o.s.jdbc.core.JdbcTemplate               : Executing SQL statement [CREATE SCHEMA two]
2018-12-07 11:49:06.176 DEBUG 5154 --- [           main] o.s.jdbc.core.JdbcTemplate               : Executing SQL statement [USE two]
2018-12-07 11:49:06.178 DEBUG 5154 --- [           main] o.s.jdbc.core.JdbcTemplate               : Executing SQL statement [CREATE TABLE user(id INT AUTO_INCREMENT PRIMARY KEY, name VARCHAR(32) CHARSET 'utf8')]
2018-12-07 11:49:06.226 DEBUG 5154 --- [           main] o.s.jdbc.core.JdbcTemplate               : Executing SQL statement [INSERT INTO user(name) VALUES ('人民的爹')]
2018-12-07 11:49:06.231 DEBUG 5154 --- [           main] o.s.jdbc.core.JdbcTemplate               : Executing SQL statement [INSERT INTO user(name) VALUES ('人民的爺')]
2018-12-07 11:49:06.235 DEBUG 5154 --- [           main] o.s.jdbc.core.JdbcTemplate               : Executing SQL statement [INSERT INTO user(name) VALUES ('人民的太爺')]
2018-12-07 11:49:06.243 DEBUG 5154 --- [           main] o.s.jdbc.core.JdbcTemplate               : Executing SQL statement [INSERT INTO user(name) VALUES ('人民的老太爺')]
2018-12-07 11:49:06.246 DEBUG 5154 --- [           main] o.s.jdbc.core.JdbcTemplate               : Executing SQL statement [USE one]
Users:
2018-12-07 11:49:06.271 DEBUG 5154 --- [           main] bj.MyBatisApp$UserMapper.selectAll       : ==> Preparing: SELECT * FROM user
2018-12-07 11:49:06.297 DEBUG 5154 --- [           main] bj.MyBatisApp$UserMapper.selectAll       : ==> Parameters:
2018-12-07 11:49:06.314 DEBUG 5154 --- [           main] bj.MyBatisApp$UserMapper.selectAll       : <==      Total: 3
{name=人民的兒子, id=1}
{name=人民的孫子, id=2}
{name=人民的曾孫子, id=3}
Secondary users:
2018-12-07 11:49:06.318 INFO 5154 --- [           main] com.zaxxer.hikari.HikariDataSource       : HikariPool-2 - Starting...
2018-12-07 11:49:06.324 INFO 5154 --- [           main] com.zaxxer.hikari.HikariDataSource       : HikariPool-2 - Start completed.
2018-12-07 11:49:06.325 DEBUG 5154 --- [           main] b.M.selectAll                            : ==> Preparing: SELECT * FROM user
2018-12-07 11:49:06.325 DEBUG 5154 --- [           main] b.M.selectAll                            : ==> Parameters:
2018-12-07 11:49:06.328 DEBUG 5154 --- [           main] b.M.selectAll                            : <==      Total: 4
{name=人民的爹, id=1}
{name=人民的爺, id=2}
{name=人民的太爺, id=3}
{name=人民的老太爺, id=4}