Spring Boot 如何整合多個(gè)數(shù)據(jù)源？

SpringBoot現(xiàn)在是很多很多公司應(yīng)用的后端框架，因?yàn)樗罱欤芨?、更快速的整合其他第三方。那么隨著業(yè)務(wù)的不斷擴(kuò)展，業(yè)務(wù)量的增加，這時(shí)候就會(huì)牽扯到分庫(kù)分表，雖然這個(gè)詞聽(tīng)起來(lái)很熟悉，作為程序員也很容易理解，但是我想應(yīng)該也有不少讀者沒(méi)接觸過(guò)分庫(kù)分表，今天我們不聊如何分庫(kù)分表，而是聊SpringBoot如何整合多個(gè)數(shù)據(jù)源的事情。也就是如何接入不同的（多個(gè)）數(shù)據(jù)庫(kù)。

我們直接開(kāi)始，我們直接創(chuàng)建一個(gè)干凈的SpringBoot應(yīng)用。

<parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>2.1.0.RELEASE</version>
    <relativePath/> <!-- lookup parent from repository -->
</parent>

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-web</artifactId>
</dependency>

<dependency>
    <groupId>org.mybatis.spring.boot</groupId>
    <artifactId>mybatis-spring-boot-starter</artifactId>
    <version>1.3.2</version>
</dependency>

<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <scope>runtime</scope>
</dependency>

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-jdbc</artifactId>
</dependency>

<dependency>
    <groupId>org.projectlombok</groupId>
    <artifactId>lombok</artifactId>
    <version>1.18.8</version>
</dependency>

引入需要的maven坐標(biāo)，那么我們這個(gè)工程就算搭建起來(lái)了，接下來(lái)就是配置，如何讓SpringBoot整合兩個(gè)Mysql數(shù)據(jù)源。首先我們?cè)诒镜貏?chuàng)建兩個(gè)數(shù)據(jù)庫(kù)test1和test2，同時(shí)在里面創(chuàng)建兩個(gè)結(jié)構(gòu)一樣的表。

CREATE TABLE `user` (
  `id` bigint(20) NOT NULL AUTO_INCREMENT COMMENT '用戶ID',
  `username` varchar(100) CHARACTER SET utf8 NOT NULL COMMENT '用戶名',
  `password` varchar(100) NOT NULL COMMENT '密碼',
  `create_time` datetime DEFAULT NULL COMMENT '創(chuàng)建時(shí)間',
  PRIMARY KEY (`id`)
) ENGINE=MyISAM AUTO_INCREMENT=3 DEFAULT CHARSET=latin1;

在我們的工程中配置application.yml文件，將數(shù)據(jù)庫(kù)的信息配置進(jìn)去

spring:
  datasource:
    test1:
      driver-class-name: com.mysql.cj.jdbc.Driver
      jdbc-url: jdbc:mysql://localhost:3306/test1?useUnicode=true&characterEncoding=utf-8&useSSL=true&serverTimezone=UTC
      username: root
      password: 1234

    test2:
      driver-class-name: com.mysql.cj.jdbc.Driver
      jdbc-url: jdbc:mysql://localhost:3306/test2?useUnicode=true&characterEncoding=utf-8&useSSL=true&serverTimezone=UTC
      username: root
      password: 1234

接下來(lái)就是寫(xiě)我們的配置類(lèi)了，這也是整合多個(gè)數(shù)據(jù)源最為關(guān)鍵的部分。

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.jdbc.datasource.DataSourceTransactionManager;

import javax.sql.DataSource;

/**
 * @ClassName DataSource2Config
 * @Description TODO
 * @Auther lbt
 * @Date 2019/6/28/028 10:07
 * @Version 1.0
 */
@Configuration
@MapperScan(basePackages = "com.example.mapper.test1", sqlSessionFactoryRef = "test1SqlSessionFactory")
public class DataSource1Config {

    @Bean(name = "test1DataSource")
    @ConfigurationProperties(prefix = "spring.datasource.test1")
    @Primary
    public DataSource test1DataSource() {
        return DataSourceBuilder.create().build();
    }

    @Bean(name = "test1SqlSessionFactory")
    @Primary
    public SqlSessionFactory test1SqlSessionFactory(@Qualifier("test1DataSource") DataSource dataSource) throws Exception {
        SqlSessionFactoryBean bean = new SqlSessionFactoryBean();
        bean.setDataSource(dataSource);
        return bean.getObject();
    }

    @Bean(name = "test1TransactionManager")
    @Primary
    public DataSourceTransactionManager test1TransactionManager(@Qualifier("test1DataSource") DataSource dataSource) {
        return new DataSourceTransactionManager(dataSource);
    }

    @Bean(name = "test1SqlSessionTemplate")
    @Primary
    public SqlSessionTemplate test1SqlSessionTemplate(@Qualifier("test1SqlSessionFactory") SqlSessionFactory sqlSessionFactory) {
        return new SqlSessionTemplate(sqlSessionFactory);
    }
}

第二個(gè)數(shù)據(jù)源的配置

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.jdbc.datasource.DataSourceTransactionManager;

import javax.sql.DataSource;

@Configuration
@MapperScan(basePackages = "com.example.mapper.test2", sqlSessionFactoryRef = "test2SqlSessionFactory")
public class DataSource2Config {

    @Bean(name = "test2DataSource")
    @ConfigurationProperties(prefix = "spring.datasource.test2")
    public DataSource test2DataSource() {
        return DataSourceBuilder.create().build();
    }

    @Bean(name = "test2SqlSessionFactory")
    public SqlSessionFactory test2SqlSessionFactory(@Qualifier("test2DataSource") DataSource dataSource) throws Exception {
        SqlSessionFactoryBean bean = new SqlSessionFactoryBean();
        bean.setDataSource(dataSource);
        return bean.getObject();
    }

    @Bean(name = "test2TransactionManager")
    public DataSourceTransactionManager test2TransactionManager(@Qualifier("test2DataSource") DataSource dataSource) {
        return new DataSourceTransactionManager(dataSource);
    }

    @Bean(name = "test2SqlSessionTemplate")
    public SqlSessionTemplate test2SqlSessionTemplate(@Qualifier("test2SqlSessionFactory") SqlSessionFactory sqlSessionFactory) {
        return new SqlSessionTemplate(sqlSessionFactory);
    }
}

這樣我們整個(gè)的配置其實(shí)就算好了，我們接下來(lái)寫(xiě)一個(gè)Controller類(lèi)來(lái)測(cè)試一下，我們整合的數(shù)據(jù)源是不是真的可以用呢？

@RestController
public class TestController {

    @Autowired
    private User1Service user1Service;

    @Autowired
    private User2Service user2Service;

    @RequestMapping("/user1")
    public Object user1Controller() {

        List<UserPo> all = user1Service.findAll();

        return all;
    }

    @RequestMapping("/user2")
    public Object user2Controller() {

        List<UserPo> all = user2Service.findAll();

        return all;
    }
}

我寫(xiě)了個(gè)兩個(gè)Controller方法，分別訪問(wèn)不同的接口，我們來(lái)看下訪問(wèn)結(jié)果。

當(dāng)我們?cè)L問(wèn)user1的時(shí)候返回如下：

當(dāng)我們?cè)L問(wèn)user2的時(shí)候訪問(wèn)如下

看到這里其實(shí)我們的整個(gè)整合也就完成了， 雖然看起來(lái)很簡(jiǎn)單，但是你如果沒(méi)寫(xiě)過(guò)確實(shí)會(huì)走很多坑，我剛整合的時(shí)候就遇到了很多坑，為了幫助大家重復(fù)采坑，分享出來(lái)供大家參考.