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MyBatis多数据源的两种配置方式

2019年07月19日  | 移动技术网IT编程  | 我要评论

前言

同一个项目有时会涉及到多个数据库，也就是多数据源。多数据源又可以分为两种情况：

1）两个或多个数据库没有相关性，各自独立，其实这种可以作为两个项目来开发。比如在游戏开发中一个数据库是平台数据库，其它还有平台下的游戏对应的数据库；

2）两个或多个数据库是master-slave的关系，比如有mysql搭建一个 master-master，其后又带有多个slave；或者采用mha搭建的master-slave复制；

mybatis多数据源的配置主要有两种方式:

  • 通过@mapperscan注解，对不同包下的mapper使用不同的sqlsessionfactory
  • 通过@mapperscan注解加自定义注解，对使用不同注解的mapper使用不同的sqlsessionfactory

第二种配置相对灵活，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多数据源演示
 */
@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个，所以需要单独再加一个配置类
  * 自定义@mapperscan会替换mybatis自动添加的默认@mapperscan。所以主@mapperscan也必须显式添加
  */
 @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 ('人民的儿子')");
  jdbctemplate.execute("insert into user(name) values ('人民的孙子')");
  jdbctemplate.execute("insert into user(name) values ('人民的曾孙子')");
  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 ('人民的爷')");
  jdbctemplate.execute("insert into user(name) values ('人民的太爷')");
  jdbctemplate.execute("insert into user(name) values ('人民的老太爷')");
  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);
 }

 /**
  * 主数据源
  * <p>
  * 如果不添加@primary注解, mybatis可以工作，但是jdbctemplate无法注入
  *
  * @return .
  */
 @primary
 @bean
 public datasource datasource() {
  return new hikaridatasource() {{
   setjdbcurl("jdbc:mysql://localhost/one?useunicode=true&characterencoding=utf8");
   setusername("root");
   setpassword("root");
  }};
 }

 /**
  * 副数据源
  *
  * @return .
  */
 @bean
 public datasource datasourcesecond() {
  return new hikaridatasource() {{
   setjdbcurl("jdbc:mysql://localhost/two?useunicode=true&characterencoding=utf8");
   setusername("root");
   setpassword("root");
  }};
 }

 /**
  * 主sqlsessionfactory。使用主数据源。自定义sqlsessionfactory后，mybatis就不自动添加sqlsessionfactory了，所以必须有
  *
  * @return .
  * @throws exception .
  */
 @bean
 public sqlsessionfactory sqlsessionfactory() throws exception {
  return new sqlsessionfactorybean() {{
   setdatasource(datasource);
  }}.getobject();
 }

 /**
  * 副sqlsessionfactory。使用副数据源
  *
  * @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();
 }

 /**
  * 自定义mapper注解，用于标识使用的数据源
  */
 @target(elementtype.type)
 @retention(retentionpolicy.runtime)
 @interface secondarymapper {
 }
}

控制台输出:

  .   ____          _            __ _ _
 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/
 :: 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 ('人民的儿子')]
2018-12-07 11:49:06.157 debug 5154 --- [           main] o.s.jdbc.core.jdbctemplate               : executing sql statement [insert into user(name) values ('人民的孙子')]
2018-12-07 11:49:06.161 debug 5154 --- [           main] o.s.jdbc.core.jdbctemplate               : executing sql statement [insert into user(name) values ('人民的曾孙子')]
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 ('人民的爷')]
2018-12-07 11:49:06.235 debug 5154 --- [           main] o.s.jdbc.core.jdbctemplate               : executing sql statement [insert into user(name) values ('人民的太爷')]
2018-12-07 11:49:06.243 debug 5154 --- [           main] o.s.jdbc.core.jdbctemplate               : executing sql statement [insert into user(name) values ('人民的老太爷')]
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=人民的儿子, id=1}
{name=人民的孙子, id=2}
{name=人民的曾孙子, 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=人民的爷, id=2}
{name=人民的太爷, id=3}
{name=人民的老太爷, id=4}

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