SpringBoot多数据源配置

作者: 上善若泪 | 来源:发表于2022-03-27 14:54 被阅读0次

最近项目用到了spring多数据源配置，恰好看到这篇好文章，特地分享下

1 SpringBoot分库配置

主要介绍两种整合方式，分别是 springboot+mybatis 使用分包方式整合，和 springboot+druid+mybatisplus 使用注解方式整合

1.1 准备数据

在本地新建两个数据库，名称分别为db1和db2，新建一张user表，表结构如下

image.png

CREATE TABLE `user` (
  `id` int(11) NOT NULL AUTO_INCREMENT COMMENT '主键',
  `name` varchar(25) NOT NULL COMMENT '姓名',
  `age` int(2) DEFAULT NULL COMMENT '年龄',
  `sex` tinyint(1) NOT NULL DEFAULT '0' COMMENT '性别：0-男，1-女',
  `addr` varchar(100) DEFAULT NULL COMMENT '地址',
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=2 DEFAULT CHARSET=utf8 COMMENT='测试用户表'

1.2 springboot+mybatis使用分包方式整合

1.2.1 pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.9.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.example</groupId>
    <artifactId>multipledatasource</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>multipledatasource</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>1.8</java.version>
    </properties>
   
    <dependencies>
        <!-- spring 依赖 -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
         <!-- mysql 依赖 -->
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>2.1.0</version>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>
</project>

1.2.2 application.yml 配置文件

server:
  port: 8080 # 启动端口
spring:
  datasource: 
    db1: # 数据源1
      jdbc-url: jdbc:mysql://localhost:3306/db1?characterEncoding=utf8&useUnicode=true&useSSL=false&serverTimezone=GMT%2B8
      username: root
      password: root
      driver-class-name: com.mysql.cj.jdbc.Driver
    db2: # 数据源2
      jdbc-url: jdbc:mysql://localhost:3306/db2?characterEncoding=utf8&useUnicode=true&useSSL=false&serverTimezone=GMT%2B8
      username: root
      password: root
      driver-class-name: com.mysql.cj.jdbc.Driver

注意事项：
各个版本的 springboot 配置 datasource 时参数有所变化，例如低版本配置数据库 url时使用 url 属性，高版本使用 jdbc-url 属性，请注意区分

1.2.3 连接数据源配置文件

1.2.3.1 连接源配置一

@Configuration
@MapperScan(basePackages = "com.example.multipledatasource.mapper.db1", sqlSessionFactoryRef = "db1SqlSessionFactory")
public class DataSourceConfig1 {

    @Primary // 表示这个数据源是默认数据源, 这个注解必须要加，因为不加的话spring将分不清楚那个为主数据源（默认数据源）
    @Bean("db1DataSource")
    @ConfigurationProperties(prefix = "spring.datasource.db1") //读取application.yml中的配置参数映射成为一个对象
    public DataSource getDb1DataSource(){
        return DataSourceBuilder.create().build();
    }

    @Primary
    @Bean("db1SqlSessionFactory")
    public SqlSessionFactory db1SqlSessionFactory(@Qualifier("db1DataSource") DataSource dataSource) throws Exception {
        SqlSessionFactoryBean bean = new SqlSessionFactoryBean();
        bean.setDataSource(dataSource);
        // mapper的xml形式文件位置必须要配置，不然将报错：no statement （这种错误也可能是mapper的xml中，namespace与项目的路径不一致导致）
        bean.setMapperLocations(new PathMatchingResourcePatternResolver().getResources("classpath*:mapping/db1/*.xml"));
        return bean.getObject();
    }

    @Primary
    @Bean("db1SqlSessionTemplate")
    public SqlSessionTemplate db1SqlSessionTemplate(@Qualifier("db1SqlSessionFactory") SqlSessionFactory sqlSessionFactory){
        return new SqlSessionTemplate(sqlSessionFactory);
    }
}

1.2.3.2 连接源配置二

@Configuration
@MapperScan(basePackages = "com.example.multipledatasource.mapper.db2", sqlSessionFactoryRef = "db2SqlSessionFactory")
public class DataSourceConfig2 {

    @Bean("db2DataSource")
    @ConfigurationProperties(prefix = "spring.datasource.db2")
    public DataSource getDb1DataSource(){
        return DataSourceBuilder.create().build();
    }

    @Bean("db2SqlSessionFactory")
    public SqlSessionFactory db1SqlSessionFactory(@Qualifier("db2DataSource") DataSource dataSource) throws Exception {
        SqlSessionFactoryBean bean = new SqlSessionFactoryBean();
        bean.setDataSource(dataSource);
        bean.setMapperLocations(new PathMatchingResourcePatternResolver().getResources("classpath*:mapping/db2/*.xml"));
        return bean.getObject();
    }

    @Bean("db2SqlSessionTemplate")
    public SqlSessionTemplate db1SqlSessionTemplate(@Qualifier("db2SqlSessionFactory") SqlSessionFactory sqlSessionFactory){
        return new SqlSessionTemplate(sqlSessionFactory);
    }
}

1.2.4 项目结构

image.png

注意事项：
在 service 层中根据不同的业务注入不同的 dao 层
如果是主从复制- -读写分离：比如 db1 中负责增删改，db2 中负责查询。但是需要注意的是负责增删改的数据库必须是主库（master）

1.3 springboot+druid+mybatisplus使用注解整合

1.3.1 pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
   <modelVersion>4.0.0</modelVersion>
   <parent>
       <groupId>org.springframework.boot</groupId>
       <artifactId>spring-boot-starter-parent</artifactId>
       <version>2.1.9.RELEASE</version>
       <relativePath/> <!-- lookup parent from repository -->
   </parent>
   <groupId>com.example</groupId>
   <artifactId>mutipledatasource2</artifactId>
   <version>0.0.1-SNAPSHOT</version>
   <name>mutipledatasource2</name>
   <description>Demo project for Spring Boot</description>

   <properties>
       <java.version>1.8</java.version>
   </properties>

   <dependencies>
       <dependency>
           <groupId>org.springframework.boot</groupId>
           <artifactId>spring-boot-starter-web</artifactId>
       </dependency>
       <dependency>
           <groupId>com.baomidou</groupId>
           <artifactId>mybatis-plus-boot-starter</artifactId>
           <version>3.2.0</version>
       </dependency>
       <dependency>
           <groupId>com.baomidou</groupId>
           <artifactId>dynamic-datasource-spring-boot-starter</artifactId>
           <version>2.5.6</version>
       </dependency>
       <dependency>
           <groupId>mysql</groupId>
           <artifactId>mysql-connector-java</artifactId>
           <scope>runtime</scope>
       </dependency>
       <dependency>
           <groupId>com.alibaba</groupId>
           <artifactId>druid-spring-boot-starter</artifactId>
           <version>1.1.20</version>
       </dependency>
       <dependency>
           <groupId>org.projectlombok</groupId>
           <artifactId>lombok</artifactId>
           <optional>true</optional>
       </dependency>
       <dependency>
           <groupId>org.springframework.boot</groupId>
           <artifactId>spring-boot-starter-test</artifactId>
           <scope>test</scope>
       </dependency>
   </dependencies>

   <build>
       <plugins>
           <plugin>
               <groupId>org.springframework.boot</groupId>
               <artifactId>spring-boot-maven-plugin</artifactId>
           </plugin>
       </plugins>
   </build>

   <profiles>
       <profile>
           <id>local1</id>
           <properties>
               <profileActive>local1</profileActive>
           </properties>
           <activation>
               <activeByDefault>true</activeByDefault>
           </activation>
       </profile>
       <profile>
           <id>local2</id>
           <properties>
               <profileActive>local2</profileActive>
           </properties>
       </profile>
   </profiles>
</project>

1.3.2 application.yml 配置文件

server:
  port: 8080
spring:
  datasource:
    dynamic:
      primary: db1 # 配置默认数据库
      datasource:
        db1: # 数据源1配置
          url: jdbc:mysql://localhost:3306/db1?characterEncoding=utf8&useUnicode=true&useSSL=false&serverTimezone=GMT%2B8
          username: root
          password: root
          driver-class-name: com.mysql.cj.jdbc.Driver
        db2: # 数据源2配置
          url: jdbc:mysql://localhost:3306/db2?characterEncoding=utf8&useUnicode=true&useSSL=false&serverTimezone=GMT%2B8
          username: root
          password: root
          driver-class-name: com.mysql.cj.jdbc.Driver
      durid:
        initial-size: 1
        max-active: 20
        min-idle: 1
        max-wait: 60000
  autoconfigure:
    exclude:  com.alibaba.druid.spring.boot.autoconfigure.DruidDataSourceAutoConfigure # 去除druid配置

DruidDataSourceAutoConfigure会注入一个DataSourceWrapper，其会在原生的spring.datasource下找 url, username, password 等。动态数据源 URL 等配置是在 dynamic 下，因此需要排除，否则会报错。排除方式有两种，一种是上述配置文件排除，还有一种可以在项目启动类排除

@SpringBootApplication(exclude = DruidDataSourceAutoConfigure.class)
public class Application {
  public static void main(String[] args) {
    SpringApplication.run(Application.class, args);
  }
}

1.3.3 使用@DS区分数据源

给使用非默认数据源添加注解@DS
@DS可以注解在 方法 上和 类 上，同时存在方法注解优先于类上注解。
注解在 service 实现或 mapper 接口方法上，不要同时在 service 和 mapper 注解

mapper上使用

@DS("db2") 
public interface UserMapper extends BaseMapper<User> {
}

service上使用

@Service
@DS("db2")
public class ModelServiceImpl extends ServiceImpl<ModelMapper, Model> implements IModelService {}

方法上使用

@Select("SELECT * FROM user")
@DS("db2")
List<User> selectAll();

转载于:https://www.cnblogs.com/aizen-sousuke/p/11756279.html

1.4 读写分离库

读写分离库使用AbstractRoutingDataSource
AbstractRoutingDataSource类和aop结合，还可以用来作为读写分离库

1.4.1 AbstractRoutingDataSource原理

AbstractRoutingDataSource原理：

Map<Object, Object> targetDataSources 保存了所有可能的数据源，key为数据库的key，value为DataSource对象或字符串形式的连接信息
Object defaultTargetDataSource 保存了默认的数据源，用于找不到具体的数据源时使用
afterPropertiesSet() 方法
解析targetDataSources数据源信息成<key,DataSource>的形式，保存在Map<Object, DataSource> resolvedDataSources 中
将defaultTargetDataSource中的默认数据源信息解析成 DataSource对象保存在 DataSource resolvedDefaultDataSource 中
determineCurrentLookupKey() 提供给子类重写，指定当前线程使用的具体的数据源的key
determineTargetDataSource() 根据 determineCurrentLookupKey()方法返回的key 返回数据源DataSouce对象，若没有，则使用默认数据源对象
getConnection() 根据determineTargetDataSource()返回的数据源，与其建立连接

1.4.2 数据源分离配置application.properties

server.port=8081
spring.datasource.jdbcUrl=jdbc:mysql://127.0.0.1:3306/spring-db-1?useUnicode=true&characterEncoding=utf8
spring.datasource.username=root
spring.datasource.password=*****
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver

y2021.spring.datasource.jdbcUrl=jdbc:mysql://127.0.0.1:3306/spring-db-2?useUnicode=true&characterEncoding=utf8
y2021.spring.datasource.username=root
y2021.spring.datasource.password=*****
y2021.spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver

logging.level.com.ijianghu.dynamic.web=debug

1.4.3 配置数据源和事务管理

@Configuration
public class BaseDataSourceConfig {

    /**
     * 配置默认数据源，并设置高优先级
     * @return
     */
    @Primary
    @Bean
    @ConfigurationProperties(prefix = "spring.datasource")
    public DataSource dataSource(){
        return DataSourceBuilder.create().build();
    }

    /**
     * 配置多数据源
     * @return
     */
    @Bean("y2021DataSource")
    @ConfigurationProperties(prefix = "y2021.spring.datasource")
    public DataSource y2021DataSource(){
        return DataSourceBuilder.create().build();
    }

    /**
     * 设置多数据源，配置动态路由数据源
     * @return
     */
    @Bean("dynamincDataSource")
    public DataSource dynamincDataSource(){
        DynamicRoutingDataSource dynamicRoutingDataSource = new DynamicRoutingDataSource();
        HashMap<Object, Object> dataSourceMap = new HashMap<>();
        dataSourceMap.put("dataSource",dataSource());
        dataSourceMap.put("y2021DataSource",y2021DataSource());
        //配置默认目标数据源
        dynamicRoutingDataSource.setDefaultTargetDataSource(dataSource());
        //设置目标数据源集合，供路由选择
        dynamicRoutingDataSource.setTargetDataSources(dataSourceMap);
        return dynamicRoutingDataSource;
    }

    /**
     * 设置会话工厂
     * @return
     * @throws Exception
     */
    @Bean(name="sqlSessionFactory")
    public SqlSessionFactory sqlSessionFactory() throws Exception {
        SqlSessionFactoryBean factoryBean = new SqlSessionFactoryBean();
        //配置数据源为多数据源
        factoryBean.setDataSource(dynamincDataSource());
        //设置mybaits的xml文件路径
        factoryBean.setMapperLocations(new PathMatchingResourcePatternResolver()
                .getResources("classpath:mapper/*.xml"));
        return factoryBean.getObject();
    }

    /**
     * 配置事务管理器
     * @return
     */
    @Bean(name="transactionManager")
    public PlatformTransactionManager transactionManager(){
        return new DataSourceTransactionManager(dynamincDataSource());
    }

}

1.4.4 继承AbstractRoutingDataSource类，实现选择目标数据源

/**
 * Multiple DataSource Configurer
 */
public class DynamicRoutingDataSource extends AbstractRoutingDataSource {
    private final Logger logger = LoggerFactory.getLogger(getClass());

    @Override
    protected Object determineCurrentLookupKey() {           
        logger.info("Current DataSource is {}",DynamicDataSourceContextHolder.getDataSourceKey());
        //从动态数据源上下文持有者里面获取
        return DynamicDataSourceContextHolder.getDataSourceKey();
    }
}

1.4.5 配置多数据源上下文持有者

public class DynamicDataSourceContextHolder {
    private final Logger logger = LoggerFactory.getLogger(getClass());
    /**
     * Maintain variable for every thread, to avoid effect other thread
     */
    private static ThreadLocal<String> CONTEXT_HOLDER = ThreadLocal.withInitial(DataSourceKey.dataSource::name);;
    /**
     * All DataSource List
     */
    public static List<Object> dataSourceKeys = new ArrayList<>();
    /**
     * Get current DataSource
     * @return data source key
     */
    public static String getDataSourceKey() {
        return CONTEXT_HOLDER.get();
    }
    public static void setDataSourceKey(String key) {
        CONTEXT_HOLDER.set(key);
    }

    public static void clearDataSourceKey() {
        CONTEXT_HOLDER.remove();
    }

  
    public static boolean containDataSourceKey(String key) {
        return dataSourceKeys.contains(key);
    }

    public static void useSlaveDataSource(String ds) {
        DataSourceKey dataSourceKey = DataSourceKey.valueOf(ds);
        //if there is no suitable enum,then use default dataSource
        if(dataSourceKey == null){
            setDataSourceKey(DataSourceKey.dataSource.dataSourceName);
        }
        setDataSourceKey(dataSourceKey.dataSourceName);
    }

    public static void useMasterDataSource() {
        CONTEXT_HOLDER.set(DataSourceKey.dataSource.dataSourceName);
    }

}

DataSourceKey类

public enum DataSourceKey {
    dataSource("dataSource","dataSource"),
    y2021("key","y2021DataSource");

    public String key;
    public String dataSourceName;
    DataSourceKey(String key, String dataSourceName){
        this.key = key;
        this.dataSourceName = dataSourceName;
    }
}

1.4.6 配置AOP切面

@Aspect
@Order(-1)//Order中的数字代表启动优先级,-1是比0还有更高的优先级
@Component
public class DynamicDataSourceAspect {
    private final Logger logger = LoggerFactory.getLogger(getClass());
    //@annotation用于匹配当前执行方法持有指定注解的方法
    @Pointcut("@annotation(org.springframework.web.bind.annotation.PostMapping)||" +
            "@annotation(org.springframework.web.bind.annotation.GetMapping)||" +
            "@annotation(org.springframework.web.bind.annotation.RequestMapping)")
    public void daoAspect(){ }


    @Before("daoAspect()")
    public void switchDataSource(JoinPoint point){
        HttpServletRequest request = ((ServletRequestAttributes) RequestContextHolder.getRequestAttributes()).getRequest();
        String ds = request.getHeader("ds");
        if(ds != null){
            DynamicDataSourceContextHolder.useSlaveDataSource(ds);
        }else{
            DynamicDataSourceContextHolder.useMasterDataSource();
        }
    }
}