springboot ssm propertis 如何搭建多数据源动态切换

1.propertis

#启动端口号
server.port=8085
# 打印 Mybatis sql 语句,两个配置都可以
#logging.level.com.example.springboot.mapper = debug
mybatis.configuration.log-impl=org.apache.ibatis.logging.stdout.StdOutImpl

#数据库1
spring.datasource.master.url=jdbc:mysql://OOO:3306/库名?characterEncoding=UTF-8&serverTimezone=GMT%2B8&useSSL=false&allowMultiQueries=true
spring.datasource.master.username =root
spring.datasource.master.password =密码
spring.datasource.master.type: com.alibaba.druid.pool.DruidDataSource
spring.datasource.master.driver-class-name: com.mysql.cj.jdbc.Driver

# 数据库2
spring.datasource.hlp[0].key: slave1
spring.datasource.hlp[0].url=jdbc:mysql://XXX:3306/test?characterEncoding=UTF-8&serverTimezone=GMT%2B8&useSSL=false&allowMultiQueries=true
spring.datasource.hlp[0].username =root
spring.datasource.hlp[0].password =密码
spring.datasource.hlp[0].type: com.alibaba.druid.pool.DruidDataSource
spring.datasource.hlp[0].driver-class-name: com.mysql.cj.jdbc.Driver

2.DynamicDataSourceRegister  数据源注册

package com;


import com.config.DynamicDataSourceContextHolder;
import com.config.DynamicRoutingDataSource;
import com.zaxxer.hikari.HikariDataSource;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.MutablePropertyValues;
import org.springframework.beans.factory.support.BeanDefinitionRegistry;
import org.springframework.beans.factory.support.GenericBeanDefinition;
import org.springframework.boot.context.properties.bind.Bindable;
import org.springframework.boot.context.properties.bind.Binder;
import org.springframework.boot.context.properties.source.ConfigurationPropertyName;
import org.springframework.boot.context.properties.source.ConfigurationPropertyNameAliases;
import org.springframework.boot.context.properties.source.ConfigurationPropertySource;
import org.springframework.boot.context.properties.source.MapConfigurationPropertySource;
import org.springframework.context.EnvironmentAware;
import org.springframework.context.annotation.ImportBeanDefinitionRegistrar;
import org.springframework.core.env.Environment;
import org.springframework.core.type.AnnotationMetadata;
import org.springframework.util.StringUtils;

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

/**
 * 动态数据源注册
 * 实现 ImportBeanDefinitionRegistrar 实现数据源注册
 * 实现 EnvironmentAware 用于读取application.yml配置
 */
@Slf4j
public class DynamicDataSourceRegister implements ImportBeanDefinitionRegistrar, EnvironmentAware {




    /**
     * 配置上下文（也可以理解为配置文件的获取工具）
     */
    private Environment evn;

    /**
     * 别名
     */
    private final static ConfigurationPropertyNameAliases aliases = new ConfigurationPropertyNameAliases();

    /**
     * 由于部分数据源配置不同，所以在此处添加别名，避免切换数据源出现某些参数无法注入的情况
     */
    static {
        aliases.addAliases("url", new String[]{"jdbc-url"});
        aliases.addAliases("username", new String[]{"hlp"});
    }

    /**
     * 存储我们注册的数据源
     */
    private Map<String, DataSource> customDataSources = new HashMap<String, DataSource>();

    /**
     * 参数绑定工具 springboot2.0新推出
     */
    private Binder binder;

    /**
     * ImportBeanDefinitionRegistrar接口的实现方法，通过该方法可以按照自己的方式注册bean
     *
     * @param annotationMetadata
     * @param beanDefinitionRegistry
     */
    @Override
    public void registerBeanDefinitions(AnnotationMetadata annotationMetadata, BeanDefinitionRegistry beanDefinitionRegistry) {
        // 获取所有数据源配置
        Map config, defauleDataSourceProperties;
        defauleDataSourceProperties = binder.bind("spring.datasource.master", Map.class).get();
        // 获取数据源类型
        String typeStr = evn.getProperty("spring.datasource.master.type");
        // 获取数据源类型
        Class<? extends DataSource> clazz = getDataSourceType(typeStr);
        // 绑定默认数据源参数 也就是主数据源
        DataSource consumerDatasource, defaultDatasource = bind(clazz, defauleDataSourceProperties);
        DynamicDataSourceContextHolder.dataSourceIds.add("master");
        log.info("注册默认数据源成功");
        // 获取其他数据源配置
        List<Map> configs = binder.bind("spring.datasource.hlp", Bindable.listOf(Map.class)).get();
        // 遍历从数据源
        for (int i = 0; i < configs.size(); i++) {
            config = configs.get(i);
            clazz = getDataSourceType((String) config.get("type"));
            defauleDataSourceProperties = config;
            // 绑定参数
            consumerDatasource = bind(clazz, defauleDataSourceProperties);
            // 获取数据源的key，以便通过该key可以定位到数据源
            String key = config.get("key").toString();
            customDataSources.put(key, consumerDatasource);
            // 数据源上下文，用于管理数据源与记录已经注册的数据源key
            DynamicDataSourceContextHolder.dataSourceIds.add(key);
            log.info("注册数据源{}成功", key);
        }
        // bean定义类
        GenericBeanDefinition define = new GenericBeanDefinition();
        // 设置bean的类型，此处DynamicRoutingDataSource是继承AbstractRoutingDataSource的实现类
        define.setBeanClass(DynamicRoutingDataSource.class);
        // 需要注入的参数
        MutablePropertyValues mpv = define.getPropertyValues();
        // 添加默认数据源，避免key不存在的情况没有数据源可用
        mpv.add("defaultTargetDataSource", defaultDatasource);
        // 添加其他数据源
        mpv.add("targetDataSources", customDataSources);
        // 将该bean注册为datasource，不使用springboot自动生成的datasource
        beanDefinitionRegistry.registerBeanDefinition("datasource", define);
        log.info("注册数据源成功，一共注册{}个数据源", customDataSources.keySet().size() + 1);
    }

    /**
     * 通过字符串获取数据源class对象
     *
     * @param typeStr
     * @return
     */
    private Class<? extends DataSource> getDataSourceType(String typeStr) {
        Class<? extends DataSource> type;
        try {
            if (StringUtils.hasLength(typeStr)) {
                // 字符串不为空则通过反射获取class对象
                type = (Class<? extends DataSource>) Class.forName(typeStr);
            } else {
                // 默认为hikariCP数据源，与springboot默认数据源保持一致
                type = HikariDataSource.class;
            }
            return type;
        } catch (Exception e) {
            //无法通过反射获取class对象的情况则抛出异常，该情况一般是写错了，所以此次抛出一个runtimeexception
            throw new IllegalArgumentException("can not resolve class with type: " + typeStr);
        }
    }

    /**
     * 绑定参数，以下三个方法都是参考DataSourceBuilder的bind方法实现的，目的是尽量保证我们自己添加的数据源构造过程与springboot保持一致
     *
     * @param result
     * @param properties
     */
    private void bind(DataSource result, Map properties) {
        ConfigurationPropertySource source = new MapConfigurationPropertySource(properties);
        Binder binder = new Binder(new ConfigurationPropertySource[]{source.withAliases(aliases)});
        // 将参数绑定到对象
        binder.bind(ConfigurationPropertyName.EMPTY, Bindable.ofInstance(result));
    }

    private <T extends DataSource> T bind(Class<T> clazz, Map properties) {
        ConfigurationPropertySource source = new MapConfigurationPropertySource(properties);
        Binder binder = new Binder(new ConfigurationPropertySource[]{source.withAliases(aliases)});
        // 通过类型绑定参数并获得实例对象
        return binder.bind(ConfigurationPropertyName.EMPTY, Bindable.of(clazz)).get();
    }

    /**
     * @param clazz
     * @param sourcePath 参数路径，对应配置文件中的值，如: spring.datasource
     * @param <T>
     * @return
     */
    private <T extends DataSource> T bind(Class<T> clazz, String sourcePath) {
        Map properties = binder.bind(sourcePath, Map.class).get();
        return bind(clazz, properties);
    }

    /**
     * EnvironmentAware接口的实现方法，通过aware的方式注入，此处是environment对象
     *
     * @param environment
     */
    @Override
    public void setEnvironment(Environment environment) {
        log.info("开始注册数据源");
        this.evn = environment;
        // 绑定配置器
        binder = Binder.get(evn);
    }

}

 3.DynamicDataSourceContextHolder 数据源上下文

package com.config;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

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

/**
 * @Auther: yukong
 * @Date: 2018/8/15 10:49
 * @Description: 数据源上下文
 */
public class DynamicDataSourceContextHolder {



    private static Logger logger = LoggerFactory.getLogger(DynamicDataSourceContextHolder.class);

    /**
     * 存储已经注册的数据源的key
     */
    public static List<String> dataSourceIds = new ArrayList<>();

    /**
     * 线程级别的私有变量
     */
    private static final ThreadLocal<String> HOLDER = new ThreadLocal<>();

    public static String getDataSourceRouterKey () {
        return HOLDER.get();
    }

    public static void setDataSourceRouterKey (String dataSourceRouterKey) {
        logger.info("切换至{}数据源", dataSourceRouterKey);
        HOLDER.set(dataSourceRouterKey);
    }

    /**
     * 设置数据源之前一定要先移除
     */
    public static void removeDataSourceRouterKey () {
        HOLDER.remove();
    }

    /**
     * 判断指定DataSrouce当前是否存在
     *
     * @param dataSourceId
     * @return
     */
    public static boolean containsDataSource(String dataSourceId){
        return dataSourceIds.contains(dataSourceId);
    }

}

4.DynamicRoutingDataSource  动态数据源路由配置

package com.config;

import lombok.extern.slf4j.Slf4j;
import org.springframework.jdbc.datasource.lookup.AbstractRoutingDataSource;

/**
 * @Auther: yukong
 * @Date: 2018/8/15 10:47
 * @Description: 动态数据源路由配置
 */
@Slf4j
public class DynamicRoutingDataSource extends AbstractRoutingDataSource {



    //private static Logger logger = LoggerFactory.getLogger(DynamicRoutingDataSource.class);

    @Override
    protected Object determineCurrentLookupKey() {
        String dataSourceName = DynamicDataSourceContextHolder.getDataSourceRouterKey();
        log.info("当前数据源是：{}", dataSourceName);
        return DynamicDataSourceContextHolder.getDataSourceRouterKey();
    }
}

5. DataSource

package com.hlp.test.annotation;

import java.lang.annotation.*;

/**
 * 切换数据注解 可以用于类或者方法级别 方法级别优先级 > 类级别
 */
@Target({ElementType.METHOD, ElementType.TYPE, ElementType.PARAMETER})
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface DataSource {
    String value() default "master"; //该值即key值    默认的数据库

}

6.DynamicDataSourceAspect

package com.aop;


import com.config.DynamicDataSourceContextHolder;
import com.hlp.test.annotation.DataSource;
import org.aspectj.lang.JoinPoint;
import org.aspectj.lang.annotation.After;
import org.aspectj.lang.annotation.Before;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

//@Aspect
//@Component
//@Order(-1900)
public class DynamicDataSourceAspect {
    private static final Logger logger = LoggerFactory.getLogger(DynamicDataSourceAspect.class);

    @Before("@annotation(ds)")
    public void changeDataSource(JoinPoint point, DataSource ds) throws Throwable {
        String dsId = ds.value();
        if (DynamicDataSourceContextHolder.dataSourceIds.contains(dsId)) {
            logger.debug("Use DataSource :{} >", dsId, point.getSignature());
            DynamicDataSourceContextHolder.setDataSourceRouterKey(dsId);
        } else {
            logger.info("数据源[{}]不存在，使用默认数据源 >{}", dsId, point.getSignature());
        }
    }

    @After("@annotation(ds)")
    public void restoreDataSource(JoinPoint point, DataSource ds) {
        logger.debug("Revert DataSource : " + ds.value() + " > " + point.getSignature());
        DynamicDataSourceContextHolder.removeDataSourceRouterKey();

    }
}

7.DynamicDataSourceAnnotationInterceptor

package com.aop;


import com.config.DynamicDataSourceContextHolder;
import com.hlp.test.annotation.DataSource;
import org.aopalliance.intercept.MethodInterceptor;
import org.aopalliance.intercept.MethodInvocation;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.core.annotation.AnnotationUtils;

import java.lang.reflect.Method;
import java.util.HashMap;
import java.util.Map;

/**
 * @Auther: yukong
 * @Date: 2018/8/17 09:15
 * @Description:
 */
public class DynamicDataSourceAnnotationInterceptor implements MethodInterceptor {

    private static final Logger logger = LoggerFactory.getLogger(DynamicDataSourceAnnotationInterceptor.class);


    /**
     * 缓存方法注解值
     */
    private static final Map<Method, String> METHOD_CACHE = new HashMap<>();

    @Override
    public Object invoke(MethodInvocation invocation) throws Throwable {
        try {
            String datasource = determineDatasource(invocation);
            if (! DynamicDataSourceContextHolder.containsDataSource(datasource)) {
                logger.info("数据源[{}]不存在，使用默认数据源 >", datasource);
            }
            DynamicDataSourceContextHolder.setDataSourceRouterKey(datasource);
            return invocation.proceed();
        } finally {
            DynamicDataSourceContextHolder.removeDataSourceRouterKey();
        }
    }

    private String determineDatasource(MethodInvocation invocation) {
        Method method = invocation.getMethod();
        if (METHOD_CACHE.containsKey(method)) {
            return METHOD_CACHE.get(method);
        } else {   //看选择那个数据源
            DataSource ds = method.isAnnotationPresent(DataSource.class) ? method.getAnnotation(DataSource.class)
                    : AnnotationUtils.findAnnotation(method.getDeclaringClass(), DataSource.class);
            METHOD_CACHE.put(method, ds.value());
            return ds.value();
        }
    }

}

8.DynamicDataSourceAnnotationAdvisor

package com.aop;


import com.hlp.test.annotation.DataSource;
import org.aopalliance.aop.Advice;
import org.springframework.aop.Pointcut;
import org.springframework.aop.support.AbstractPointcutAdvisor;
import org.springframework.aop.support.ComposablePointcut;
import org.springframework.aop.support.annotation.AnnotationMatchingPointcut;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.BeanFactory;
import org.springframework.beans.factory.BeanFactoryAware;

/**
 * @Auther: yukong
 * @Date: 2018/8/17 09:14
 * @Description: aop织入
 */
public class DynamicDataSourceAnnotationAdvisor extends AbstractPointcutAdvisor implements BeanFactoryAware {

    private Advice advice;

    private Pointcut pointcut;

    public DynamicDataSourceAnnotationAdvisor(DynamicDataSourceAnnotationInterceptor dynamicDataSourceAnnotationInterceptor) {
        this.advice = dynamicDataSourceAnnotationInterceptor;
        this.pointcut = buildPointcut();
    }

    @Override
    public Pointcut getPointcut() {
        return this.pointcut;
    }

    @Override
    public Advice getAdvice() {
        return this.advice;
    }

    @Override
    public void setBeanFactory(BeanFactory beanFactory) throws BeansException {
        if (this.advice instanceof BeanFactoryAware) {
            ((BeanFactoryAware) this.advice).setBeanFactory(beanFactory);
        }
    }

    private Pointcut buildPointcut() {
        Pointcut cpc = (Pointcut) new AnnotationMatchingPointcut(DataSource.class, true);
        // 类注解
        Pointcut clpc = (Pointcut) AnnotationMatchingPointcut.forClassAnnotation(DataSource.class);
        // 方法注解
        Pointcut mpc = (Pointcut) AnnotationMatchingPointcut.forMethodAnnotation(DataSource.class);
        return new ComposablePointcut(cpc).union(clpc).union(mpc);
    }

}

9.  启动类

package com.zdkj.umt;

import com.DynamicDataSourceRegister;
import com.aop.DynamicDataSourceAnnotationAdvisor;
import com.aop.DynamicDataSourceAnnotationInterceptor;
import lombok.extern.slf4j.Slf4j;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.web.servlet.ServletComponentScan;
import org.springframework.context.ConfigurableApplicationContext;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Import;
import org.springframework.scheduling.annotation.EnableScheduling;
import org.springframework.transaction.annotation.EnableTransactionManagement;

/** 启动类
 * @author liuyanjun
 */
@Slf4j
@Import(DynamicDataSourceRegister.class)
@EnableTransactionManagement
@ServletComponentScan
@SpringBootApplication
@MapperScan("com.zdkj.umt.mapper")
@EnableScheduling
public class SpringbootApplication {

//最主要的是这里  要注入  不然无法切换数据源
    @Bean
    public DynamicDataSourceAnnotationAdvisor dynamicDatasourceAnnotationAdvisor() {
        return new DynamicDataSourceAnnotationAdvisor(new DynamicDataSourceAnnotationInterceptor());
    }

    public static void main(String[] args) {
        ConfigurableApplicationContext ctx = SpringApplication.run(SpringbootApplication.class, args);
        String[] activeProfiles = ctx.getEnvironment().getActiveProfiles();
        for (String profile : activeProfiles) {
            log.info("▁▂▃▄▅▆▇█    Spring Boot 使用profile：" + profile + "    █▇▆▅▄▃▂▁");
        }
    }

}

10. 测试时使用  UserMapper

package com.zdkj.umt.mapper;

import com.hlp.test.annotation.DataSource;
import com.zdkj.umt.domain.po.hlp;

import java.util.List;

/**
 * describe
 *
 * @author HuangLinPan
 * @date 2020/05/18
 */
//如果方法上没有配置数据库那么就看mapper上的
//如果也没有那么就使用  DataSource 默认的数据库
@DataSource("slave1")
public interface UserMapper {
　　

//优先看方法上的库名   

    @DataSource("slave1")
    List<hlp> getAllUser();
}

此为使用别人源码配置 (笔记)