How to implement SpringBoot multiple data source switching-javaTutorial-php.cn

Configuration file (YML)

spring:
  datasource:
    default-db-key: voidme
    multi-db:
      - voidme:
          driver-class-name: com.mysql.cj.jdbc.Driver
          username: root
          password: root
          url: jdbc:mysql://192.168.42.153:3306/voidme?characterEncoding=utf8&autoReconnect=true&failOverReadOnly=false&maxReconnects=10&useSSL=false
      - xcdef:
          driver-class-name: com.mysql.cj.jdbc.Driver
          username: root
          password: root
          url: jdbc:mysql://192.168.42.153:3306/xcdef?characterEncoding=utf8&autoReconnect=true&failOverReadOnly=false&maxReconnects=10&useSSL=false


mybatis:
  #1.classpath：只会到你的classes路径中查找找文件。
  #2.classpath*：不仅会到classes路径，还包括jar文件中(classes路径)进行查找。
  mapper-locations: classpath*:/mapper/**/*Mapper.xml    # mapper映射文件位置
  type-aliases-package: com.**.entity    # 实体类所在的位置
  configuration:
    log-impl: org.apache.ibatis.logging.stdout.StdOutImpl   #用于控制台打印sql语句
    map-underscore-to-camel-case: true #开启将带有下划线的表字段 映射为驼峰格式的实体类属性

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Core code

How to implement SpringBoot multiple data source switching

DynamicDataSource

This class is used to obtain the data source (core)

package com.dynamicdatadource.dynamic;

import org.springframework.beans.factory.annotation.Value;
import org.springframework.jdbc.datasource.lookup.AbstractRoutingDataSource;

public class DynamicDataSource extends AbstractRoutingDataSource {

    @Value("${spring.datasource.default-db-key}")
    private String defaultDbKey;

    @Override
    protected Object determineCurrentLookupKey() {
        String currentDb = DynamicDataSourceService.currentDb();
        if (currentDb == null) {
            return defaultDbKey;
        }
        return currentDb;
    }
}

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DynamicDataSourceService

This class is a data source switching tool. We have done thread isolation, so there is no need to worry about the confusion of multi-threaded data sources. Problem

package com.dynamicdatadource.dynamic;

import com.application.ApplicationContextProvider;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.boot.jdbc.DataSourceBuilder;

import javax.sql.DataSource;
import java.util.HashMap;
import java.util.Map;

public class DynamicDataSourceService  {
    private static final Logger log = LoggerFactory.getLogger(DynamicDataSourceService.class);

    private static final Map<Object, Object> dataSources = new HashMap<>();
    private static final ThreadLocal<String> dbKeys = ThreadLocal.withInitial(() -> null);

    /**
     * 动态添加一个数据源
     *
     * @param name       数据源的key
     * @param dataSource 数据源对象
     */
    public static void addDataSource(String name, DataSource dataSource) {
        DynamicDataSource dynamicDataSource = ApplicationContextProvider.getApplicationContext().getBean(DynamicDataSource.class);
        dataSources.put(name, dataSource);
        dynamicDataSource.setTargetDataSources(dataSources);
        dynamicDataSource.afterPropertiesSet();
        log.info("添加了数据源:{}",name);
    }

    /**
     * @param name   数据源的key
     * @param driverClassName  驱动
     * @param url     数据库连接地址
     * @param username   数据库账户
     * @param password   数据库密码
     */
    public static void addDataSource(String name, String driverClassName,String url,String username,String password) {
        DataSourceBuilder<?> builder = DataSourceBuilder.create();
        builder.driverClassName(driverClassName);
        builder.username(username);
        builder.password(password);
        builder.url(url);
        addDataSource(name,builder.build());
        log.info("添加了数据源:{}",name);
    }
    /**
     * 切换数据源
     */
    public static void switchDb(String dbKey) {
        dbKeys.set(dbKey);
    }

    /**
     * 重置数据源(切换为默认的数据源)
     */
    public static void resetDb() {
        dbKeys.remove();
    }

    /**
     * 获取当前数据源的key
     */
    public static String currentDb() {
        return dbKeys.get();
    }
}

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DynamicDataSourceConfig

Configuring the data source into springboot and initializing the Mybaitis configuration

package com.dynamicdatadource.dynamic;

import lombok.Data;
import org.apache.ibatis.logging.Log;
import org.mybatis.spring.SqlSessionFactoryBean;
import org.springframework.boot.context.properties.ConfigurationProperties;
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 org.springframework.transaction.PlatformTransactionManager;

import java.io.IOException;
import java.util.HashMap;
import java.util.Map;

@Configuration
@ConfigurationProperties(prefix = "mybatis")
@Data
public class DynamicDataSourceConfig {

    private String mapperLocations;
    private String typeAliasesPackage;
    @Data
    public class MybatisConfiguration{
        private String logImpl;
        private boolean mapUnderscoreToCamelCase;
    }
    private  MybatisConfiguration configuration=new MybatisConfiguration();


    /**
     * 动态数据源
     */
    @Bean
    public DynamicDataSource dynamicDataSource() {
        DynamicDataSource dataSource = new DynamicDataSource();
        Map<Object, Object> targetDataSources = new HashMap<>();
        dataSource.setTargetDataSources(targetDataSources);
        return dataSource;
    }

    /**
     * 会话工厂Mybaitis
     */
    @Bean
    public SqlSessionFactoryBean sqlSessionFactoryBean() throws IOException, ClassNotFoundException {
        org.apache.ibatis.session.Configuration configuration = new org.apache.ibatis.session.Configuration();
        configuration.setMapUnderscoreToCamelCase(this.configuration.isMapUnderscoreToCamelCase()); //开启驼峰命名
        configuration.setLogImpl((Class<? extends Log>) Class.forName(this.configuration.getLogImpl())); //控制台打印sql日志
        SqlSessionFactoryBean sqlSessionFactoryBean = new SqlSessionFactoryBean();
        sqlSessionFactoryBean.setDataSource(dynamicDataSource());
        sqlSessionFactoryBean.setConfiguration(configuration);
        PathMatchingResourcePatternResolver resolver = new PathMatchingResourcePatternResolver();
        sqlSessionFactoryBean.setMapperLocations(resolver.getResources(mapperLocations));
        sqlSessionFactoryBean.setTypeAliasesPackage(typeAliasesPackage);
        return sqlSessionFactoryBean;
    }

    /**
     * 事务管理器
     */
    @Bean
    public PlatformTransactionManager transactionManager() {
        return new DataSourceTransactionManager(dynamicDataSource());
    }
}

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Loading the YML database configuration class

package com.dynamicdatadource.config;

import com.dynamicdatadource.dynamic.DynamicDataSourceService;
import lombok.Data;
import org.springframework.boot.autoconfigure.jdbc.DataSourceProperties;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.boot.jdbc.DataSourceBuilder;
import org.springframework.stereotype.Component;

import javax.annotation.PostConstruct;
import javax.sql.DataSource;
import java.util.List;
import java.util.Map;
import java.util.Set;

@Component
@Data
@ConfigurationProperties(prefix = "spring.datasource")
public class YmlDataSourceProvider  {

    private List<Map<String, DataSourceProperties>> multiDb;

    private DataSource buildDataSource(DataSourceProperties prop) {
        DataSourceBuilder<?> builder = DataSourceBuilder.create();
        builder.driverClassName(prop.getDriverClassName());
        builder.username(prop.getUsername());
        builder.password(prop.getPassword());
        builder.url(prop.getUrl());
        return builder.build();
    }

    public void initDataSource() {
        multiDb.forEach(map -> {
            Set<String> keys = map.keySet();
            keys.forEach(key -> {
                DataSourceProperties properties = map.get(key);
                DataSource dataSource = buildDataSource(properties);
                DynamicDataSourceService.addDataSource(key, dataSource);
            });
        });
    }

    //在构造函数之后执行
    @PostConstruct
    public void init() {
        initDataSource();
    }
}

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aop switching

package com.dynamicdatadource.aop;

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

@Target({ElementType.METHOD,ElementType.TYPE})//作用:方法和类
@Retention(RetentionPolicy.RUNTIME)
public @interface DynamicDataSourceAnno {
    String key() default "";
}

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package com.dynamicdatadource.aop;
import com.dynamicdatadource.dynamic.DynamicDataSourceService;
import org.apache.commons.lang.StringUtils;
import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.Around;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Pointcut;
import org.aspectj.lang.reflect.MethodSignature;
import org.springframework.stereotype.Component;

// 用于单独的请求或者类进行切换数据库
@Aspect
@Component
public class DynamicDataSourceAspect {
    @Pointcut("@annotation(com.dynamicdatadource.aop.DynamicDataSourceAnno)")
    public void dynamicDataSourceAnno() {
    }

    @Around("dynamicDataSourceAnno()")
    public Object DynamicDataSourceAspectAroundAnno(ProceedingJoinPoint joinPoint) {
        Object object = null;
        try {
            MethodSignature signature = (MethodSignature)joinPoint.getSignature();
            DynamicDataSourceAnno dynamicDataSourceAnno  = signature.getMethod().getAnnotation(DynamicDataSourceAnno.class);
            String key = dynamicDataSourceAnno.key();
            if (StringUtils.isNotBlank(key)) {
                //切换为指定数据库
                DynamicDataSourceService.switchDb(key);
            }
            object = joinPoint.proceed();
        } catch (Throwable e) {
            e.printStackTrace();
        }finally {
            //还原为默认配置
            DynamicDataSourceService.resetDb();
        }
        return object;
    }
    // 还可以扩展包路径切换
}

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Effect

After running the program, the data source will be added to the data source list

How to implement SpringBoot multiple data source switching

Extension

MysqlDataSourceInitialize

Query the configuration information from the database and then dynamically add it to the data source list

package com.dao.config;

import com.dao.DatasourceDao;
import com.dynamicdatadource.aop.DynamicDataSourceAnno;
import com.dynamicdatadource.dynamic.DynamicDataSourceService;
import com.entity.DataSourceEneity;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.ApplicationArguments;
import org.springframework.boot.ApplicationRunner;
import org.springframework.stereotype.Component;

import javax.annotation.PostConstruct;
import javax.sql.DataSource;
import java.util.List;

//从数据库中查询出全部的数据源,添加到数据源容器中

/**
 * 表结构如下:
 *
 * CREATE TABLE `t_datasource` (
 *   `id` int(11) NOT NULL,
 *   `key` varchar(255) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NOT NULL COMMENT &#39;绑定的key,用于数据源的切换&#39;,
 *   `url` text CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NOT NULL COMMENT &#39;数据库连接地址&#39;,
 *   `username` varchar(255) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NOT NULL COMMENT &#39;数据库用户名&#39;,
 *   `password` varchar(255) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NOT NULL COMMENT &#39;数据库密码&#39;,
 *   `driverClassName` varchar(255) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NOT NULL COMMENT &#39;数据库驱动&#39;,
 *   `type` varchar(50) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NOT NULL COMMENT &#39;数据库类型:  mysql ,oracle,..&#39;,
 *   `state` int(2) NOT NULL COMMENT &#39;是否可用: 1可用 ,2不可用&#39;,
 *   PRIMARY KEY (`id`),
 *   UNIQUE KEY `key` (`key`)
 * ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_general_ci;
 *
 * 上表要放入到默认数据源中的数据库里才行
 */
@Component
public class MysqlDataSourceInitialize implements ApplicationRunner  {

    @Autowired
    private DatasourceDao datasourceDao;

    //项目启动后执行初始化数据源
    @Override
    public void run(ApplicationArguments args) throws Exception {
        try {
            List<DataSourceEneity> dataSources = datasourceDao.getDataSources();
            for (DataSourceEneity dataSource : dataSources) {
                DynamicDataSourceService.addDataSource(dataSource.getKey(),dataSource.getDataSource());
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

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DataSourceEneity entity class

@Data
public class DataSourceEneity {
    private int id;
    private String key;
    private String url;
    private String username;
    private String password;
    private String driverClassName;
    private String type;
    private int state;

    public  DataSource getDataSource() {
        DataSourceBuilder<?> builder = DataSourceBuilder.create();
        builder.driverClassName(driverClassName);
        builder.username(username);
        builder.password(password);
        builder.url(url);
        return  builder.build();
    }
}

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