springboot+mybatis+druid+多数据源的问题分析

这篇文章主要介绍springboot+mybatis+druid+多数据源的问题分析，文中介绍的非常详细，具有一定的参考价值，感兴趣的小伙伴们一定要看完！

一. 简介

俩个数据库db1,db2， db1数据库的mapper.xml和db2数据库的mapper.xml分别放到不同的目录下, 通过给不同的目录配置不同的数据源，并分别监控各自的事务。

已有新版方案： Mybatis Plus整合多数据源和读写分离，请使用新版；

二. sql脚本

db1数据库的user表：

CREATE TABLE `user` (  `id` int(11) NOT NULL,  `name` varchar(255) DEFAULT NULL,  PRIMARY KEY (`id`)) ENGINE=InnoDB DEFAULT CHARSET=utf8;

db2数据库的role表：

CREATE TABLE `role` (  `id` int(11) NOT NULL,  `name` varchar(255) DEFAULT NULL,  PRIMARY KEY (`id`)) ENGINE=InnoDB DEFAULT CHARSET=utf8;

三. 工程搭建

3.1 目录结构图

3.2 pom.xml文件

    4.0.0     com.example    datasources    0.0.1-SNAPSHOT    jar     datasources    Demo project for Spring Boot             org.springframework.boot        spring-boot-starter-parent        2.0.4.RELEASE                         UTF-8        UTF-8        1.8                              org.springframework.boot            spring-boot-starter-web                             org.mybatis.spring.boot            mybatis-spring-boot-starter            1.3.2                             mysql            mysql-connector-java            runtime                             org.springframework.boot            spring-boot-starter-test            test                             org.apache.commons            commons-lang3            3.4                             com.fasterxml.jackson.core            jackson-core                            com.fasterxml.jackson.core            jackson-databind                            com.fasterxml.jackson.datatype            jackson-datatype-joda                            com.fasterxml.jackson.module            jackson-module-parameter-names                            org.springframework.boot            spring-boot-starter-aop                                     com.github.pagehelper            pagehelper-spring-boot-starter            1.2.5                                     com.alibaba            druid-spring-boot-starter            1.1.9                             org.springframework.boot            spring-boot-starter-thymeleaf                             org.springframework.boot            spring-boot-starter-jdbc                                     org.springframework.boot            spring-boot-starter-jta-atomikos                                     io.springfox            springfox-swagger2            2.6.1                            io.springfox            springfox-swagger-ui            2.6.1                                                               org.springframework.boot                spring-boot-maven-plugin                         

3.3 application.yml

server:  port: 8080  spring:  datasource:    db1:      driverClassName: com.mysql.jdbc.Driver      username: 用户名      password: 密码      # spring2.0此处为jdbc-url      jdbc-url: jdbc:mysql://IP:3306/db1?useUnicode=true&characterEncoding=UTF-8&allowMultiQueries=true      type: com.alibaba.druid.pool.DruidDataSource    db2:      driverClassName: com.mysql.jdbc.Driver      username: 用户名      password: 密码      # spring2.0此处为jdbc-url      jdbc-url: jdbc:mysql://IP:3306/db2?useUnicode=true&characterEncoding=UTF-8&allowMultiQueries=true      type: com.alibaba.druid.pool.DruidDataSource

3.4 数据源配置类

3.4.1 db1数据库的数据源 （主数据源@Primary）

package com.example.datasources.datasource; import org.apache.ibatis.session.SqlSessionFactory;import org.mybatis.spring.SqlSessionFactoryBean;import org.mybatis.spring.SqlSessionTemplate;import org.mybatis.spring.annotation.MapperScan;import org.springframework.beans.factory.annotation.Qualifier;import org.springframework.boot.context.properties.ConfigurationProperties;import org.springframework.boot.jdbc.DataSourceBuilder;import org.springframework.context.annotation.Bean;import org.springframework.context.annotation.Configuration;import org.springframework.context.annotation.Primary;import org.springframework.core.io.support.PathMatchingResourcePatternResolver;import org.springframework.jdbc.datasource.DataSourceTransactionManager; import javax.sql.DataSource; @Configuration@MapperScan(basePackages = "com.example.datasources.mapper.db1", sqlSessionTemplateRef = "db1SqlSessionTemplate")public class DataSource1Config {     @Bean    @ConfigurationProperties(prefix = "spring.datasource.db1")    @Primary    public DataSource db1DataSource() {        return DataSourceBuilder.create().build();    }     @Bean    @Primary    public SqlSessionFactory db1SqlSessionFactory(@Qualifier("db1DataSource") DataSource dataSource) throws Exception {        SqlSessionFactoryBean bean = new SqlSessionFactoryBean();        bean.setDataSource(dataSource);        bean.setMapperLocations(new PathMatchingResourcePatternResolver().getResources("classpath*:com/example/datasources/mapper/db1/*.xml"));        return bean.getObject();    }     @Bean    @Primary    public DataSourceTransactionManager db1TransactionManager(@Qualifier("db1DataSource") DataSource dataSource) {        return new DataSourceTransactionManager(dataSource);    }     @Bean    @Primary    public SqlSessionTemplate db1SqlSessionTemplate(@Qualifier("db1SqlSessionFactory") SqlSessionFactory sqlSessionFactory) throws Exception {        return new SqlSessionTemplate(sqlSessionFactory);    } }

3.4.2 db2数据库的数据源

package com.example.datasources.datasource; import org.apache.ibatis.session.SqlSessionFactory;import org.mybatis.spring.SqlSessionFactoryBean;import org.mybatis.spring.SqlSessionTemplate;import org.mybatis.spring.annotation.MapperScan;import org.springframework.beans.factory.annotation.Qualifier;import org.springframework.boot.context.properties.ConfigurationProperties;import org.springframework.boot.jdbc.DataSourceBuilder;import org.springframework.context.annotation.Bean;import org.springframework.context.annotation.Configuration;import org.springframework.core.io.support.PathMatchingResourcePatternResolver;import org.springframework.jdbc.datasource.DataSourceTransactionManager; import javax.sql.DataSource; @Configuration@MapperScan(basePackages = "com.example.datasources.mapper.db2", sqlSessionTemplateRef = "db2SqlSessionTemplate")public class DataSource2Config {     @Bean    @ConfigurationProperties(prefix = "spring.datasource.db2")    public DataSource db2DataSource() {        return DataSourceBuilder.create().build();    }     @Bean    public SqlSessionFactory db2SqlSessionFactory(@Qualifier("db2DataSource") DataSource dataSource) throws Exception {        SqlSessionFactoryBean bean = new SqlSessionFactoryBean();        bean.setDataSource(dataSource);        bean.setMapperLocations(new PathMatchingResourcePatternResolver().getResources("classpath*:com/example/datasources/mapper/db2/*.xml"));        return bean.getObject();    }     @Bean    public DataSourceTransactionManager db2TransactionManager(@Qualifier("db2DataSource") DataSource dataSource) {        return new DataSourceTransactionManager(dataSource);    }     @Bean    public SqlSessionTemplate db2SqlSessionTemplate(@Qualifier("db2SqlSessionFactory") SqlSessionFactory sqlSessionFactory) throws Exception {        return new SqlSessionTemplate(sqlSessionFactory);    }  }

3.5 Controller

3.5.1 db1的UserController

package com.example.datasources.controller; import com.example.datasources.entity.db1.User;import com.example.datasources.service.UserService;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.web.bind.annotation.*; import java.util.List; @RestController@RequestMapping("/user")public class UserController {     @Autowired    private UserService userService;     @GetMapping("/select/list")    public List selectUserList() {        return this.userService.selectUserList();    }     @GetMapping("/save")    public void saveUser(User user) {        this.userService.saveUser(user);    }  }

3.5.2 db2的RoleController

package com.example.datasources.controller; import com.example.datasources.entity.db2.Role;import com.example.datasources.service.RoleService;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.web.bind.annotation.GetMapping;import org.springframework.web.bind.annotation.RequestMapping;import org.springframework.web.bind.annotation.RestController; import java.util.List; @RestController@RequestMapping("/role")public class RoleController {     @Autowired    private RoleService roleService;     @GetMapping("/select/list")    public List selectRoleList() {        return this.roleService.selectRoleList();    }     @GetMapping("/save")    public void saveRole(Role role) {        this.roleService.saveRole(role);    }  }

3.6 Service

3.6.1 db1的UserService

package com.example.datasources.service; import com.example.datasources.entity.db1.User; import java.util.List; public interface UserService {     List selectUserList();     void saveUser(User user); }

3.6.2 db2的RoleService

package com.example.datasources.service; import com.example.datasources.entity.db2.Role; import java.util.List; public interface RoleService {     List selectRoleList();     void saveRole(Role role); }

3.7 serviceImpl

3.7.1 db1的UserServiceImpl

package com.example.datasources.service.impl; import com.example.datasources.entity.db1.User;import com.example.datasources.mapper.db1.UserMapper;import com.example.datasources.service.UserService;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.stereotype.Service;import org.springframework.transaction.annotation.Transactional; import java.util.List; @Servicepublic class UserServiceImpl implements UserService {     @Autowired    private UserMapper userMapper;     @Override    public List selectUserList() {        return this.userMapper.selectUserList();    }     @Transactional    @Override    public void saveUser(User user) {        this.userMapper.saveUser(user);//        throw new RuntimeException();    }}

3.7.2 db2的RoleServiceImpl

package com.example.datasources.service.impl; import com.example.datasources.entity.db2.Role;import com.example.datasources.mapper.db2.RoleMapper;import com.example.datasources.service.RoleService;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.stereotype.Service;import org.springframework.transaction.annotation.Transactional; import java.util.List; @Servicepublic class RoleServiceImpl implements RoleService {     @Autowired    private RoleMapper roleMapper;     @Override    public List selectRoleList() {        return this.roleMapper.selectRoleList();    }     // 注：不是主数据源必须要声明其数据源，否则事务不起作用    @Transactional(value = "db2TransactionManager")    @Override    public void saveRole(Role role) {        this.roleMapper.saveRole(role);//        throw new RuntimeException();    }}

3.8 mapper

3.8.1 db1的UserMapper

package com.example.datasources.mapper.db1; import com.example.datasources.entity.db1.User; import java.util.List; public interface UserMapper {     List selectUserList();     void saveUser(User user); }

3.8.2 db2的RoleMapper

package com.example.datasources.mapper.db2; import com.example.datasources.entity.db2.Role; import java.util.List; public interface RoleMapper {     List selectRoleList();     void saveRole(Role role);}

3.9 mapper.xml

3.9.1 db1的UserMapper.xml

                                       id, `name`                  SELECT                  FROM `user`                  INSERT INTO `user`           (id, `name`)        VALUES           ( #{id}, #{name} )     

3.9.2 db2的RoleMapper.xml

                                      id, name                 SELECT                  FROM          role                  INSERT INTO `role`           (id, `name`)        VALUES           ( #{id}, #{name} )     

3.10 entity

3.10.1 db1的User

package com.example.datasources.entity.db1; public class User {     private Integer id;    private String name;     public User() {    }     public User(Integer id, String name) {        this.id = id;        this.name = name;    }     public Integer getId() {        return id;    }     public void setId(Integer id) {        this.id = id;    }     public String getName() {        return name;    }     public void setName(String name) {        this.name = name;    }}

3.10.2 db2的Role

package com.example.datasources.entity.db2; public class Role {     private Integer id;    private String name;     public Role() {    }     public Role(Integer id, String name) {        this.id = id;        this.name = name;    }     public Integer getId() {        return id;    }     public void setId(Integer id) {        this.id = id;    }     public String getName() {        return name;    }     public void setName(String name) {        this.name = name;    } }

3.11 启动类

package com.example.datasources; import org.springframework.boot.SpringApplication;import org.springframework.boot.autoconfigure.SpringBootApplication; @SpringBootApplicationpublic class DatasourcesApplication {     public static void main(String[] args) {        SpringApplication.run(DatasourcesApplication.class, args);    }}

四. 测试

可以直接在浏览器测试，测试事务的时候可以将异常打开。

需要注意的是： 非主数据源必须要在@Transactional注解中指定数据源，否则事务不起作用。主数据库不需要。

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