SpringBoot自定义+动态切换数据源教程

<dependency>
            <groupId>Mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid</artifactId>
            <version>1.1.3</version>
        </dependency>
        <!--properties动态注入-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-configuration-processor</artifactId>
            <optional>true</optional>
        </dependency>
        <!--SpringBoot的aop-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-aop</artifactId>
        </dependency>

# 数据库访问配置
# 主数据源，默认的
druid:
  datasource:
    type: com.alibaba.druid.pool.DruidDataSource
    driver-class-name: com.mysql.jdbc.Driver
    url: jdbc:mysql://192.168.1.113:3306/test?useUnicode=true&characterEncoding=utf-8
    username: root
    passWord: root
    # 下面为连接池的补充设置，应用到上面所有数据源中
    # 初始化大小，最小，最大
    initialSize: 5
    minIdle: 5
    maxActive: 20
    # 配置获取连接等待超时的时间
    maxWait: 60000
    # 配置间隔多久才进行一次检测，检测需要关闭的空闲连接，单位是毫秒
    timeBetweenEvictionRunsMillis: 60000
    # 配置一个连接在池中最小生存的时间，单位是毫秒
    minEvictableIdleTimeMillis: 300000
    validationQuery: SELECT 1 FROM DUAL
    testWhileIdle: true
    testOnBorrow: false
    testOnReturn: false
    # 打开PSCache，并且指定每个连接上PSCache的大小
    poolPreparedStatements: true
    maxPoolPreparedStatementPerConnectionSize: 20
    # 配置监控统计拦截的filters，去掉后监控界面sql无法统计，'wall'用于防火墙
    filters: stat,wall,log4j
    # 通过connectProperties属性来打开mergeSql功能；慢SQL记录
    connectionProperties:
      druid:
        stat:
          mergeSql: true
          slowSqlMillis: 5000
    # 合并多个DruidDataSource的监控数据
#多数据源
mysql-db:
  datasource:
    names: logic,dao
    logic:
      driver-class-name: com.mysql.jdbc.Driver
      url: jdbc:mysql://192.168.1.113:3306/test1?useUnicode=true&characterEncoding=utf-8
      username: root
      password: root
    dao:
      driver-class-name: com.mysql.jdbc.Driver
      url: jdbc:mysql://192.168.1.113:3306/test2?useUnicode=true&characterEncoding=utf-8
      username: root
      password: root

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

public class DynamicDataSource extends AbstractRoutingDataSource {
    @Override
    protected Object determineCurrentLookupKey() {
        return DataSourceHolder.getDataSource();
    }
}

import java.util.ArrayList;
import java.util.List;

public class DataSourceHolder {
    //线程本地环境
    private static final ThreadLocal<String> contextHolders = new ThreadLocal<String>();
    //数据源列表
    public static List<String> dataSourceIds = new ArrayList<>();
    //设置数据源
    public static void setDataSource(String customerType) {
        contextHolders.set(customerType);
    }
    //获取数据源
    public static String getDataSource() {
        return (String) contextHolders.get();
    }
    //清除数据源
    public static void clearDataSource() {
        contextHolders.remove();
    }
    
    public static boolean containsDataSource(String dataSourceId){
        return dataSourceIds.contains(dataSourceId);
    }
}

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.MutablePropertyValues;
import org.springframework.beans.PropertyValues;
import org.springframework.boot.autoconfigure.jdbc.DataSourceBuilder;
import org.springframework.boot.bind.RelaxedDataBinder;
import org.springframework.boot.bind.RelaxedPropertyResolver;
import org.springframework.context.EnvironmentAware;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.convert.ConversionService;
import org.springframework.core.convert.support.DefaultConversionService;
import org.springframework.core.env.Environment;
import org.springframework.stereotype.Component;
import javax.sql.DataSource;
import java.util.HashMap;
import java.util.Map;

@Component
@Configuration
public class DynamicDataSourceConfig implements EnvironmentAware {
    private static final Logger logger = LoggerFactory.getLogger(DynamicDataSourceConfig.class);
    // 默认数据源
    private DataSource defaultDataSource;
    // 属性值
    private PropertyValues dataSourcePropertyValues;
    // 如配置文件中未指定数据源类型，使用该默认值
    private static final Object DATASOURCE_TYPE_DEFAULT = "org.apache.Tomcat.jdbc.pool.DataSource";
    private ConversionService conversionService = new DefaultConversionService();
    private Map<String, DataSource> customDataSources = new HashMap<>();
    @Override
    public void setEnvironment(Environment environment) {
        initDefaultDatasource(environment);
        initOtherDatasource(environment);
    }
    private void initOtherDatasource(Environment environment) {
        RelaxedPropertyResolver propertyResolver = new RelaxedPropertyResolver(environment, "mysql-db.datasource.");
        String dsPrefixs = propertyResolver.getProperty("names");
        for (String dsPrefix : dsPrefixs.split(",")) {// 多个数据源
            Map<String, Object> dsMap = propertyResolver.getSubProperties(dsPrefix+".");
            DataSource ds = buildDataSource(dsMap);
            customDataSources.put(dsPrefix, ds);
            dataBinder(ds, environment);
        }
    }
    private void initDefaultDatasource(Environment environment) {
        // 读取主数据源
        RelaxedPropertyResolver propertyResolver = new RelaxedPropertyResolver(environment, "druid.datasource.");
        Map<String, Object> dsMap = new HashMap<>();
        dsMap.put("type", propertyResolver.getProperty("type"));
        dsMap.put("driver-class-name", propertyResolver.getProperty("driver-class-name"));
        dsMap.put("url", propertyResolver.getProperty("url"));
        dsMap.put("username", propertyResolver.getProperty("username"));
        dsMap.put("password", propertyResolver.getProperty("password"));
        defaultDataSource = buildDataSource(dsMap);
        DataSourceHolder.dataSourceIds.add("ds1");
        dataBinder(defaultDataSource, environment);
    }
    
    @SuppressWarnings("unchecked")
    public DataSource buildDataSource(Map<String, Object> dsMap) {
        try {
            Object type = dsMap.get("type");
            if (type == null)
                type = DATASOURCE_TYPE_DEFAULT;// 默认DataSource
            Class<? extends DataSource> dataSourceType;
            dataSourceType = (Class<? extends DataSource>) Class.forName((String) type);
            String driverClassName = dsMap.get("driver-class-name").toString();
            String url = dsMap.get("url").toString();
            String username = dsMap.get("username").toString();
            String password = dsMap.get("password").toString();
            DataSourceBuilder factory = DataSourceBuilder.create().driverClassName(driverClassName).url(url)
                    .username(username).password(password).type(dataSourceType);
            return factory.build();
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        }
        return null;
    }
    
    private void dataBinder(DataSource dataSource, Environment env){
        RelaxedDataBinder dataBinder = new RelaxedDataBinder(dataSource);
        //dataBinder.setValidator(new LocalValidatorFactory().run(this.applicationContext));
        dataBinder.setConversionService(conversionService);
        dataBinder.setIgnoreNestedProperties(false);//false
        dataBinder.setIgnoreInvalidFields(false);//false
        dataBinder.setIgnoreUnknownFields(true);//true
        if(dataSourcePropertyValues == null){
            Map<String, Object> rpr = new RelaxedPropertyResolver(env, "druid.datasource.").getSubProperties(".");
            Map<String, Object> values = new HashMap<>(rpr);
            // 排除已经设置的属性
            values.remove("type");
            values.remove("driver-class-name");
            values.remove("url");
            values.remove("username");
            values.remove("password");
            dataSourcePropertyValues = new MutablePropertyValues(values);
        }
        dataBinder.bind(dataSourcePropertyValues);
    }
    @Bean(name = "dataSource")
    public DynamicDataSource dataSource() {
        DynamicDataSource dynamicDataSource = new DynamicDataSource();
        // 默认数据源
        dynamicDataSource.setDefaultTargetDataSource(defaultDataSource);
        // 配置多数据源
        Map<Object, Object> dsMap = new HashMap(5);
        dsMap.put("ds1", defaultDataSource);
        dsMap.putAll(customDataSources);
        for (String key : customDataSources.keySet())
            DataSourceHolder.dataSourceIds.add(key);
        dynamicDataSource.setTargetDataSources(dsMap);
        return dynamicDataSource;
    }
}

@Retention(RetentionPolicy.RUNTIME)
@Target({
        ElementType.METHOD
})
public @interface DS {
    String name() default "ds1";
}

import com.chen.config.dynamicDS.DataSourceHolder;
import org.aspectj.lang.JoinPoint;
import org.aspectj.lang.annotation.After;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Before;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.core.annotation.Order;
import org.springframework.stereotype.Component;

@Aspect
@Order(-1)// 保证该AOP在@Transactional之前执行
@Component
public class DynamicDataSourceAspect {
    private static final Logger logger = LoggerFactory.getLogger(DynamicDataSourceAspect.class);
    @Before("@annotation(ds)")
    public void changeDataSource(JoinPoint point, DS ds) throws Throwable {
        String dsId = ds.name();
        if (!DataSourceHolder.containsDataSource(dsId)) {
            logger.error("数据源[{}]不存在，使用默认数据源 > {}", ds.name(), point.getSignature());
        } else {
            logger.debug("Use DataSource : {} > {}", ds.name(), point.getSignature());
            DataSourceHolder.setDataSource(ds.name());
        }
    }
    @After("@annotation(ds)")
    public void restoreDataSource(JoinPoint point, DS ds) {
        logger.debug("Revert DataSource : {} > {}", ds.name(), point.getSignature());
        DataSourceHolder.clearDataSource();
    }
}

public interface DynamicDSMapper {
    Integer queryJournal();
    String queryUser();
    String queryType();
}

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "Http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.chen.mapper.DynamicDSMapper">
    <select id="queryJournal" resultType="java.lang.Integer">
        SELECT uid FROM journal
    </select>
    <select id="queryUser" resultType="java.lang.String">
        SELECT name FROM user
    </select>
    <select id="queryType" resultType="java.lang.String">
        SELECT parent FROM p_type
    </select>
</mapper>

@Service
public class DynamicServciceImpl implements DynamicServcice {
    @Autowired
    private DynamicDSMapper dynamicDSMapper;
    @DS()
    public Integer ds1() {
        return dynamicDSMapper.queryJournal();
    }
    @DS(name = "logic")
    public String ds2() {
        return dynamicDSMapper.queryUser();
    }
    @DS(name = "dao")
    public String ds3() {
        return dynamicDSMapper.queryType();
    }
}

@RunWith(SpringRunner.class)
@SpringBootTest
public class TestDynamicDS {
    private Logger logger = LoggerFactory.getLogger(TestDynamicDS.class);
//
    @Autowired
    private DynamicServcice dynamicServcice;
    @Test
    public void test() {
//        Integer integer = dynamicServcice.ds1();
//        logger.info("integer:"+integer);
//        String ds2 = dynamicServcice.ds2();
//        logger.info("ds2:"+ds2);
        String ds3 = dynamicServcice.ds3();
        logger.info("ds3:"+ds3);
    }
}