自我救赎之路—（springboot 配置多种数据源）

配置连接多个数据库

说明，最近要做一个数据处理服务器，一方面是要调用数据服务器自己的数据库，另一方面是要调用业务数据库. .net分分种钟搞定，但是这个springboot 不太了解，说真的，我是在网上早的，但还是整理一下。

1. 先来贴pom.xml 文件内容：

<?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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.bom</groupId>
    <artifactId>dataservice</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>

    <name>dataservice</name>
    <description>Demo project for Spring Boot</description>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.8.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.8</java.version>
        <!-- mysql驱动版本号 -->
        <mysql-driver.version>5.1.29</mysql-driver.version>
    </properties>

    <dependencies>
        <!--<dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>1.3.1</version>
        </dependency>-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web-services</artifactId>
        </dependency>

        <!--<dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
        </dependency>-->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>${mysql-driver.version}</version>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>io.springfox</groupId>
            <artifactId>springfox-swagger2</artifactId>
            <version>2.6.1</version>
        </dependency>
        <dependency>
            <groupId>io.springfox</groupId>
            <artifactId>springfox-swagger-ui</artifactId>
            <version>2.6.1</version>
        </dependency>

        <dependency>
            <groupId>io.springfox</groupId>
            <artifactId>springfox-staticdocs</artifactId>
            <version>2.6.1</version>
        </dependency>
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>fastjson</artifactId>
            <version>1.2.8</version>
        </dependency>

        <dependency>
            <groupId>org.springframework.restdocs</groupId>
            <artifactId>spring-restdocs-mockmvc</artifactId>
            <exclusions>
                <exclusion>
                    <artifactId>spring-test</artifactId>
                    <groupId>org.springframework</groupId>
                </exclusion>
            </exclusions>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-test-autoconfigure</artifactId>
        </dependency>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
        </dependency>
        <dependency>
            <groupId>org.apache.httpcomponents</groupId>
            <artifactId>httpcore</artifactId>
            <version>4.4.6</version>
        </dependency>
        <dependency>
            <groupId>antlr</groupId>
            <artifactId>antlr</artifactId>
            <version>2.7.7</version>
        </dependency>
        <dependency>
            <groupId>org.apache.httpcomponents</groupId>
            <artifactId>httpclient</artifactId>
            <version>4.5.2</version>
        </dependency>
        <dependency>
            <groupId>org.apache.httpcomponents</groupId>
            <artifactId>httpcore</artifactId>
            <version>4.4.6</version>
        </dependency>
        <dependency>
            <groupId>org.apache.httpcomponents</groupId>
            <artifactId>httpclient</artifactId>
            <version>4.5.2</version>
        </dependency>
        <dependency>
            <groupId>org.apache.httpcomponents</groupId>
            <artifactId>httpcore</artifactId>
            <version>4.4.6</version>
        </dependency>

        <!-- springjpa
            springjpa中带有自带的tomcat 数据连接池;
           在代码中我们也需要用到.
      -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>
        <dependency>
            <groupId>ant</groupId>
            <artifactId>ant</artifactId>
            <version>1.6.5</version>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-surefire-plugin</artifactId>
                <configuration>
                    <includes>
                        <include>**/*Documentation.java</include>
                    </includes>
                </configuration>
            </plugin>
            <plugin>
                <groupId>org.asciidoctor</groupId>
                <artifactId>asciidoctor-maven-plugin</artifactId>
                <version>1.5.3</version>

                <!-- Configure generic document generation settings -->
                <configuration>
                    <sourceDirectory>${project.basedir}/docs/asciidoc</sourceDirectory>
                    <sourceDocumentName>index.adoc</sourceDocumentName>
                    <attributes>
                        <doctype>book</doctype>
                        <toc>left</toc>
                        <toclevels>3</toclevels>
                        <numbered></numbered>
                        <hardbreaks></hardbreaks>
                        <sectlinks></sectlinks>
                        <sectanchors></sectanchors>
                        <generated>${project.build.directory}/asciidoc</generated>
                    </attributes>
                </configuration>
                <!-- Since each execution can only handle one backend, run
                     separate executions for each desired output type -->
                <executions>
                    <execution>
                        <id>output-html</id>
                        <phase>test</phase>
                        <goals>
                            <goal>process-asciidoc</goal>
                        </goals>
                        <configuration>
                            <backend>html5</backend>
                            <!--<outputDirectory>${project.basedir}/docs/asciidoc/html</outputDirectory>-->
                        </configuration>
                    </execution>
                </executions>
            </plugin>

        </plugins>
    </build>


</project>

2. 再来看帖出来的代码：

a. DynamicDataSource

package com.bom.dataservice.config;

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

/**
 * Created by chenwangming on 2017/11/14.
 */
public class DynamicDataSource  extends AbstractRoutingDataSource {
    /*
       *代码中的determineCurrentLookupKey方法取得一个字符串，
       *该字符串将与配置文件中的相应字符串进行匹配以定位数据源，配置文件，即applicationContext.xml文件中需要要如下代码：(non-Javadoc)
       * @seeorg.springframework.jdbc.datasource.lookup.AbstractRoutingDataSource#determineCurrentLookupKey()
       */
    @Override
    protected Object determineCurrentLookupKey() {
              /*
               * DynamicDataSourceContextHolder代码中使用setDataSourceType
               *设置当前的数据源，在路由类中使用getDataSourceType进行获取，
               * 交给AbstractRoutingDataSource进行注入使用。
               */
        return DynamicDataSourceContextHolder.getDataSourceType();
    }
}

b. DynamicDataSourceAspect

package com.bom.dataservice.config;

/**
 * Created by chenwangming on 2017/11/14.
 */


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.springframework.core.annotation.Order;
import org.springframework.stereotype.Component;

/**
 *切换数据源Advice
 *@author 陈王明
 *@version v.0.1
 */
@Aspect
@Order(-10)//保证该AOP在@Transactional之前执行
@Component
public class DynamicDataSourceAspect {
    /*
           * @Before("@annotation(ds)")
           *的意思是：
           *
           * @Before：在方法执行之前进行执行：
           * @annotation(targetDataSource)：
           *会拦截注解targetDataSource的方法，否则不拦截;
           */
    @Before("@annotation(targetDataSource)")
    public void changeDataSource(JoinPoint point, TargetDataSource targetDataSource) throws Throwable {
        //获取当前的指定的数据源;
        String dsId = targetDataSource.value();
        //如果不在我们注入的所有的数据源范围之内，那么输出警告信息，系统自动使用默认的数据源。
        if (!DynamicDataSourceContextHolder.containsDataSource(dsId)) {
            System.err.println("数据源[{}]不存在，使用默认数据源 > {}"+targetDataSource.value()+point.getSignature());
        } else {
            System.out.println("UseDataSource : {} > {}"+targetDataSource.value()+point.getSignature());
            //找到的话，那么设置到动态数据源上下文中。
            DynamicDataSourceContextHolder.setDataSourceType(targetDataSource.value());
        }
    }

    @After("@annotation(targetDataSource)")
    public void restoreDataSource(JoinPoint point, TargetDataSource targetDataSource) {
        System.out.println("RevertDataSource : {} > {}"+targetDataSource.value()+point.getSignature());
        //方法执行完毕之后，销毁当前数据源信息，进行垃圾回收。
        DynamicDataSourceContextHolder.clearDataSourceType();
    }
}

c. DynamicDataSourceContextHolder

package com.bom.dataservice.config;

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

/**
 * Created by chenwangming on 2017/11/14.
 */
public class DynamicDataSourceContextHolder {
    /*
        *当使用ThreadLocal维护变量时，ThreadLocal为每个使用该变量的线程提供独立的变量副本，
        *所以每一个线程都可以独立地改变自己的副本，而不会影响其它线程所对应的副本。
        */
    private static final ThreadLocal<String>contextHolder = new ThreadLocal<String>();
    /*
     *管理所有的数据源id;
     *主要是为了判断数据源是否存在;
     */
    public static List<String> dataSourceIds =new ArrayList<String>();

    /**
     *使用setDataSourceType设置当前的
     *@param dataSourceType
     */
    public static void setDataSourceType(String dataSourceType) {
        contextHolder.set(dataSourceType);
    }

    public static String getDataSourceType() {
        return contextHolder.get();
    }

    public static void clearDataSourceType() {
        contextHolder.remove();
    }

    /**
     *判断指定DataSrouce当前是否存在
     *
     *@param dataSourceId
     *@return
     *@author 陈王明
     *@create  2017年11月14日
     */
    public static boolean containsDataSource(String dataSourceId){
        return dataSourceIds.contains(dataSourceId);
    }
}

d. DynamicDataSourceRegister

package com.bom.dataservice.config;
import java.util.HashMap;
import java.util.Map;
import javax.sql.DataSource;
import org.springframework.beans.MutablePropertyValues;
import org.springframework.beans.PropertyValues;
import org.springframework.beans.factory.support.BeanDefinitionRegistry;
import org.springframework.beans.factory.support.GenericBeanDefinition;
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.ImportBeanDefinitionRegistrar;
import org.springframework.core.convert.ConversionService;
import org.springframework.core.convert.support.DefaultConversionService;
import org.springframework.core.env.Environment;
import org.springframework.core.type.AnnotationMetadata;

/**
 * Created by chenwangming on 2017/11/14.
 */
public class DynamicDataSourceRegister implements ImportBeanDefinitionRegistrar, EnvironmentAware{
    //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 PropertyValues dataSourcePropertyValues;

    // 默认数据源
    private DataSource defaultDataSource;

    private Map<String, DataSource> customDataSources = new HashMap<String, DataSource>();

    /**
     *加载多数据源配置
     */
    @Override
    public void setEnvironment(Environment environment) {
        System.out.println("DynamicDataSourceRegister.setEnvironment()");
        initDefaultDataSource(environment);
        initCustomDataSources(environment);
    }

    /**
     *加载主数据源配置.
     *@param env
     */
    private void initDefaultDataSource(Environment env){
        // 读取主数据源
        RelaxedPropertyResolver propertyResolver =new RelaxedPropertyResolver(env,"spring.datasource.");
        Map<String,Object>dsMap = new HashMap<String, Object>();
        dsMap.put("type", propertyResolver.getProperty("type"));
        dsMap.put("driverClassName", propertyResolver.getProperty("driverClassName"));
        dsMap.put("url", propertyResolver.getProperty("url"));
        dsMap.put("username", propertyResolver.getProperty("username"));
        dsMap.put("password", propertyResolver.getProperty("password"));

        //创建数据源;
        defaultDataSource =buildDataSource(dsMap);
        dataBinder(defaultDataSource,env);
    }

    /**
     *初始化更多数据源
     *
     *@author 陈王明
     *@create 2017年11月14日
     */
    private void initCustomDataSources(Environment env) {
        //读取配置文件获取更多数据源，也可以通过defaultDataSource读取数据库获取更多数据源
        RelaxedPropertyResolver propertyResolver = new RelaxedPropertyResolver(env,"custom.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,env);
        }
    }

    /**
     *创建datasource.
     *@param dsMap
     *@return
     */
    @SuppressWarnings("unchecked")
    public DataSource buildDataSource(Map<String, Object>dsMap) {
        Object type =dsMap.get("type");
        if (type ==null){
            type = DATASOURCE_TYPE_DEFAULT;//默认DataSource
        }
        Class<? extends DataSource>dataSourceType;

        try {
            dataSourceType = (Class<? extends DataSource>)Class.forName((String)type);
            String driverClassName =dsMap.get("driverClassName").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;
    }

    /**
     *为DataSource绑定更多数据
     *@param dataSource
     *@param env
     */
    private void dataBinder(DataSource dataSource, Environment env){
        RelaxedDataBinder dataBinder =new RelaxedDataBinder(dataSource);
        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,"spring.datasource").getSubProperties(".");
            Map<String, Object>values = new HashMap<>(rpr);
            // 排除已经设置的属性
            values.remove("type");
            values.remove("driverClassName");
            values.remove("url");
            values.remove("username");
            values.remove("password");
            dataSourcePropertyValues = new MutablePropertyValues(values);
        }
        dataBinder.bind(dataSourcePropertyValues);

    }


    @Override
    public void registerBeanDefinitions(AnnotationMetadata importingClassMetadata,BeanDefinitionRegistry registry) {
        System.out.println("DynamicDataSourceRegister.registerBeanDefinitions()");
        Map<Object,Object>targetDataSources = new HashMap<Object, Object>();
        // 将主数据源添加到更多数据源中
        targetDataSources.put("dataSource", defaultDataSource);
        DynamicDataSourceContextHolder.dataSourceIds.add("dataSource");
        // 添加更多数据源
        targetDataSources.putAll(customDataSources);
        for (String key : customDataSources.keySet()) {
            DynamicDataSourceContextHolder.dataSourceIds.add(key);
        }
        // 创建DynamicDataSource
        GenericBeanDefinition beanDefinition = new GenericBeanDefinition();
        beanDefinition.setBeanClass(DynamicDataSource.class);
        beanDefinition.setSynthetic(true);
        MutablePropertyValues mpv = beanDefinition.getPropertyValues();
        //添加属性：AbstractRoutingDataSource.defaultTargetDataSource
        mpv.addPropertyValue("defaultTargetDataSource",defaultDataSource);
        mpv.addPropertyValue("targetDataSources",targetDataSources);
        registry.registerBeanDefinition("dataSource",beanDefinition);
    }

}

e. TargetDataSource

package com.bom.dataservice.config;

/**
 * Created by chenwangming on 2017/11/14.
 */

import java.lang.annotation.*;

/**
 *在方法上使用，用于指定使用哪个数据源
 *@author 陈王明
 *@version v.0.1
 */
@Target({ ElementType.METHOD, ElementType.TYPE })
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface TargetDataSource {
    String value();
}

3. 最后再启动类中注册动态数据源类

package com.bom.dataservice;

import com.bom.dataservice.config.DynamicDataSourceRegister;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.Import;

@SpringBootApplication
@Import({DynamicDataSourceRegister.class}) //这个就是注册类
public class DataserviceApplication {

    public static void main(String[] args) {
        SpringApplication.run(DataserviceApplication.class, args);
    }
}

总结一下，到这里就搞定了，因为能力有限，描述不足，当保证能用，后期在来补充。

---

经历过黑暗，才有对光明的渴望；经历过风雨，才懂得阳光的温暖；经历过沧桑，才拥有温柔的内心；经历人生最好的成长。

今天对面坐了一位美女，心情很激动，导致我没有用心去写博客。

共同学习，共同进步，技术交流群：210470210