Mybatis多数据源的切换——AbstractRoutingDataSource

Spring数据源路由核心类AbstractRoutingDataSource，API文档解释如下：

Abstract javax.sql.DataSource implementation that routes getConnection() calls to one of various target DataSources based on a lookup key. The latter is usually (but not necessarily) determined through some thread-bound transaction context.

抽象javax.sql.DataSource实现，该实现将基于查询键的getConnection()调用路由到各种目标DataSource之一。后者通常（但不是必须）通过某些线程绑定的事务上下文来确定。

实现思路

一、application.xml配置

##druid和数据库配置
spring.datasource.type=com.alibaba.druid.pool.DruidDataSource
#primary：前端埋点数据相关
spring.datasource.druid.primary.url=jdbc:mysql://100.11.4.16:3306/spider?useUnicode=true&characterEncoding=utf8&serverTimezone=Asia/Shanghai&connectTimeout=5000
spring.datasource.druid.primary.username=root
spring.datasource.druid.primary.password=123456
spring.datasource.druid.primary.driverClassName=com.mysql.jdbc.Driver
#vice：数据同步任务监控相关
spring.datasource.druid.vice.url=jdbc:mysql://100.11.4.16:3306/spider_monitor?useUnicode=true&characterEncoding=utf8&serverTimezone=Asia/Shanghai&connectTimeout=5000
spring.datasource.druid.vice.username=root
spring.datasource.druid.vice.password=123456
spring.datasource.druid.vice.driverClassName=com.mysql.jdbc.Driver
#公共配置
spring.datasource.druid.initial-size=10
spring.datasource.druid.max-active=100
spring.datasource.druid.min-idle=30
spring.datasource.druid.max-wait=30000
spring.datasource.druid.pool-prepared-statements=true
spring.datasource.druid.max-pool-prepared-statement-per-connection-size=20
spring.datasource.druid.time-between-eviction-runs-millis=60000
spring.datasource.druid.min-evictable-idle-time-millis=300000
spring.datasource.druid.max-evictable-idle-time-millis=60000
spring.datasource.druid.validation-query=SELECT 1 FROM DUAL
#spring.datasource.druid.validation-query-timeout=5000
spring.datasource.druid.test-on-borrow=false
spring.datasource.druid.test-on-return=false
spring.datasource.druid.test-while-idle=true
spring.datasource.druid.connectionProperties=druid.stat.mergeSql=true;druid.stat.slowSqlMillis=5000
#filters: #配置多个英文逗号分隔(统计，sql注入，log4j过滤)
spring.datasource.druid.filters=stat,wall
spring.datasource.druid.stat-view-servlet.enabled=true
spring.datasource.druid.stat-view-servlet.url-pattern=/druid/*

#mybatis配置
mybatis.mapper-locations=classpath:mapper/*Mapper.xml
mybatis.type-aliases-package=com.cjia.spidercommon.model
#mybatis.config-location=classpath:mybatis.cfg.xml

二、定义数据源key

我这里的服务需要操作两个数据源，一个主一个副，定义如下：

package com.cjia.spidersink.jdbc;

/**
 * 多数据源的key
 */
public enum DatabaseType {
	spiderprimary, spidervice
}

三、定义数据源key持有类

package com.cjia.spidersink.jdbc;

/**
 * 数据源key持有类
 */
public class DatabaseContextHolder {

	private static final ThreadLocal<DatabaseType> contextHolder = new ThreadLocal<>();

	public static void setDatabaseType(DatabaseType type) {
		contextHolder.set(type);
	}

	public static DatabaseType getDatabaseType() {
		return contextHolder.get();
	}
}

四、定义动态数据源

继承Spring数据源路由核心类AbstractRoutingDataSource。

package com.cjia.spidersink.jdbc;

import org.springframework.jdbc.datasource.lookup.AbstractRoutingDataSource;

/**
 * 固定动态多数据源
 */
public class DynamicDatasource extends AbstractRoutingDataSource {

	@Override
	protected Object determineCurrentLookupKey() {
		return DatabaseContextHolder.getDatabaseType();
	}
}

五、数据源配置

这里使用了druid数据库连接池，配置如下：

package com.cjia.spidersink.config;

import java.util.HashMap;
import java.util.Map;

import javax.sql.DataSource;

import org.apache.ibatis.session.SqlSessionFactory;
import org.mybatis.spring.SqlSessionFactoryBean;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.boot.web.servlet.FilterRegistrationBean;
import org.springframework.boot.web.servlet.ServletRegistrationBean;
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.core.JdbcTemplate;
import org.springframework.jdbc.datasource.DataSourceTransactionManager;
import org.springframework.transaction.support.TransactionTemplate;

import com.alibaba.druid.pool.DruidDataSource;
import com.alibaba.druid.support.http.StatViewServlet;
import com.alibaba.druid.support.http.WebStatFilter;
import com.cjia.spidersink.jdbc.DatabaseType;
import com.cjia.spidersink.jdbc.DynamicDatasource;

/**
 * Druid数据库连接池配置文件
 */
@Configuration
public class DruidConfig {
    private static final Logger logger = LoggerFactory.getLogger(DruidConfig.class);

    @Value("${spring.datasource.druid.primary.url}")
    private String dbUrl4Primary;

    @Value("${spring.datasource.druid.primary.username}")
    private String username4Primary;

    @Value("${spring.datasource.druid.primary.password}")
    private String password4Primary;

    @Value("${spring.datasource.druid.primary.driverClassName}")
    private String driverClassName4Primary;

    @Value("${spring.datasource.druid.vice.url}")
    private String dbUrl4Vice;

    @Value("${spring.datasource.druid.vice.username}")
    private String username4Vice;

    @Value("${spring.datasource.druid.vice.password}")
    private String password4Vice;

    @Value("${spring.datasource.druid.vice.driverClassName}")
    private String driverClassName4Vice;

    @Value("${spring.datasource.druid.initial-size}")
    private int initialSize;

    @Value("${spring.datasource.druid.max-active}")
    private int maxActive;

    @Value("${spring.datasource.druid.min-idle}")
    private int minIdle;

    @Value("${spring.datasource.druid.max-wait}")
    private int maxWait;

    @Value("${spring.datasource.druid.pool-prepared-statements}")
    private boolean poolPreparedStatements;

    @Value("${spring.datasource.druid.max-pool-prepared-statement-per-connection-size}")
    private int maxPoolPreparedStatementPerConnectionSize;

    @Value("${spring.datasource.druid.time-between-eviction-runs-millis}")
    private int timeBetweenEvictionRunsMillis;

    @Value("${spring.datasource.druid.min-evictable-idle-time-millis}")
    private int minEvictableIdleTimeMillis;

    @Value("${spring.datasource.druid.max-evictable-idle-time-millis}")
    private int maxEvictableIdleTimeMillis;

    @Value("${spring.datasource.druid.validation-query}")
    private String validationQuery;

    @Value("${spring.datasource.druid.test-while-idle}")
    private boolean testWhileIdle;

    @Value("${spring.datasource.druid.test-on-borrow}")
    private boolean testOnBorrow;

    @Value("${spring.datasource.druid.test-on-return}")
    private boolean testOnReturn;

    @Value("${spring.datasource.druid.filters}")
    private String filters;

    @Value("{spring.datasource.druid.connection-properties}")
    private String connectionProperties;

    /**
     * Druid 连接池配置 主数据源:前端埋点数据相关
     */
    @Bean
    @Primary
    public DruidDataSource dataSource4Primary() {
        DruidDataSource datasource = new DruidDataSource();
        datasource.setUrl(dbUrl4Primary);
        datasource.setUsername(username4Primary);
        datasource.setPassword(password4Primary);
        datasource.setDriverClassName(driverClassName4Primary);
        datasource.setInitialSize(initialSize);
        datasource.setMinIdle(minIdle);
        datasource.setMaxActive(maxActive);
        datasource.setMaxWait(maxWait);
        datasource.setTimeBetweenEvictionRunsMillis(timeBetweenEvictionRunsMillis);
        datasource.setMinEvictableIdleTimeMillis(minEvictableIdleTimeMillis);
        datasource.setMaxEvictableIdleTimeMillis(minEvictableIdleTimeMillis);
        datasource.setValidationQuery(validationQuery);
        datasource.setTestWhileIdle(testWhileIdle);
        datasource.setTestOnBorrow(testOnBorrow);
        datasource.setTestOnReturn(testOnReturn);
        datasource.setPoolPreparedStatements(poolPreparedStatements);
        datasource.setMaxPoolPreparedStatementPerConnectionSize(maxPoolPreparedStatementPerConnectionSize);
        try {
            datasource.setFilters(filters);
        } catch (Exception e) {
            logger.error("Primary druid configuration initialization filter", e);
        }
        datasource.setConnectionProperties(connectionProperties);
        return datasource;
    }

    /**
     * Druid 连接池配置 副数据源:数据同步任务监控相关
     */
    @Bean
    public DruidDataSource dataSource4Vice() {
        DruidDataSource datasource = new DruidDataSource();
        datasource.setUrl(dbUrl4Vice);
        datasource.setUsername(username4Vice);
        datasource.setPassword(password4Vice);
        datasource.setDriverClassName(driverClassName4Vice);
        datasource.setInitialSize(initialSize);
        datasource.setMinIdle(minIdle);
        datasource.setMaxActive(maxActive);
        datasource.setMaxWait(maxWait);
        datasource.setTimeBetweenEvictionRunsMillis(timeBetweenEvictionRunsMillis);
        datasource.setMinEvictableIdleTimeMillis(minEvictableIdleTimeMillis);
        datasource.setMaxEvictableIdleTimeMillis(minEvictableIdleTimeMillis);
        datasource.setValidationQuery(validationQuery);
        datasource.setTestWhileIdle(testWhileIdle);
        datasource.setTestOnBorrow(testOnBorrow);
        datasource.setTestOnReturn(testOnReturn);
        datasource.setPoolPreparedStatements(poolPreparedStatements);
        datasource.setMaxPoolPreparedStatementPerConnectionSize(maxPoolPreparedStatementPerConnectionSize);
        try {
            datasource.setFilters(filters);
        } catch (Exception e) {
            logger.error("Vice druid configuration initialization filter", e);
        }
        datasource.setConnectionProperties(connectionProperties);
        return datasource;
    }

    @Bean
    public DynamicDatasource datasource(@Qualifier("dataSource4Primary") DataSource primaryDataSource, @Qualifier("dataSource4Vice") DataSource viceDataSource) {
	Map<Object, Object> targetDataSources = new HashMap<>();
	targetDataSources.put(DatabaseType.spiderprimary, primaryDataSource);
	targetDataSources.put(DatabaseType.spidervice, viceDataSource);

	DynamicDatasource datasource = new DynamicDatasource();
	// 该方法是AbstractRoutingDataSource的方法
	datasource.setTargetDataSources(targetDataSources);
	// 默认的datasource设置为primary
	datasource.setDefaultTargetDataSource(primaryDataSource);
	return datasource;
    }

    @Bean
    public SqlSessionFactory sqlSessionFactory(@Autowired DynamicDatasource ds) throws Exception {
    	SqlSessionFactoryBean fb = new SqlSessionFactoryBean();
    	fb.setDataSource(ds);
    	fb.setTypeAliasesPackage("com.cjia.spidercommon.model");
    	fb.setMapperLocations(new PathMatchingResourcePatternResolver().getResources("classpath:mapper/*Mapper.xml"));
    	return fb.getObject();
    }

    /**
     * 配置 Druid 监控界面
     */
    @Bean
    public ServletRegistrationBean statViewServlet() {
        ServletRegistrationBean srb =
                new ServletRegistrationBean(new StatViewServlet(),"/druid/*");
        //设置控制台管理用户
        srb.addInitParameter("loginUsername","root");
        srb.addInitParameter("loginPassword","root");
        //是否可以重置数据
        srb.addInitParameter("resetEnable","false");
        return srb;
    }

    @Bean
    public FilterRegistrationBean statFilter() {
        //创建过滤器
        FilterRegistrationBean frb =
                new FilterRegistrationBean(new WebStatFilter());
        //设置过滤器过滤路径
        frb.addUrlPatterns("/*");
        //忽略过滤的形式
        frb.addInitParameter("exclusions",
                "*.js,*.gif,*.jpg,*.png,*.css,*.ico,/druid/*");
        return frb;
    }
}

六、dao层切换数据源

在各个dao类中，mapper接口操作之前，切换到对应的数据源即可。

package com.cjia.spidersink.dao;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Repository;

import com.cjia.spidercommon.model.MonitorHistory;
import com.cjia.spidersink.jdbc.DatabaseContextHolder;
import com.cjia.spidersink.jdbc.DatabaseType;
import com.cjia.spidersink.mapper.MonitorHistoryMapper;

@Repository
public class MonitorHistoryDao {

	@Autowired
	private MonitorHistoryMapper monitorHistoryMapper;

	public void update(MonitorHistory history) {
		DatabaseContextHolder.setDatabaseType(DatabaseType.spidervice);
		monitorHistoryMapper.update(history);
	}
}

至此。

DayDayUp丶

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