springboot2动态数据源的绑定

由于springboot2更新了绑定参数的api，部分springboot1用于绑定的工具类如RelaxedPropertyResolver已经无法在新版本中使用。本文实现参考了https://blog.csdn.net/catoop/article/details/50575038这篇文章，大致思路是一致的，如果需要详细实现可以参考。都是通过AbstractRoutingDataSource实现动态数据源的切换，以前我用spring配置多数据源的时候就是通过它实现的，有兴趣的可以了解下其原理，这里就不多赘述了。

废话不多说了，先上数据源注册工具类，springboot2与1的主要区别也就在这：

MultiDataSourceRegister.java：

package top.ivan.demo.springboot.mapper;

import com.zaxxer.hikari.HikariDataSource;

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;

public class MultiDataSourceRegister implements EnvironmentAware, ImportBeanDefinitionRegistrar {
</span><span style="color: #0000ff;">private</span> <span style="color: #0000ff;">final</span> <span style="color: #0000ff;">static</span> ConfigurationPropertyNameAliases aliases = <span style="color: #0000ff;">new</span> ConfigurationPropertyNameAliases(); <span style="color: #008000;">//</span><span style="color: #008000;">别名</span>

<span style="color: #0000ff;">static</span><span style="color: #000000;"> {
    </span><span style="color: #008000;">//</span><span style="color: #008000;">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</span>
    aliases.addAliases("url", <span style="color: #0000ff;">new</span> String[]{"jdbc-url"<span style="color: #000000;">});
    aliases.addAliases(</span>"username", <span style="color: #0000ff;">new</span> String[]{"user"<span style="color: #000000;">});
}

</span><span style="color: #0000ff;">private</span> Environment evn; <span style="color: #008000;">//</span><span style="color: #008000;">配置上下文（也可以理解为配置文件的获取工具）</span>

<span style="color: #0000ff;">private</span> Map&lt;String, DataSource&gt; sourceMap;  <span style="color: #008000;">//</span><span style="color: #008000;">数据源列表</span>

<span style="color: #0000ff;">private</span> Binder binder; <span style="color: #008000;">//</span><span style="color: #008000;">参数绑定工具</span>

<span style="color: #008000;">/**</span><span style="color: #008000;">
 * 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
 *
 * </span><span style="color: #808080;">@param</span><span style="color: #008000;"> annotationMetadata
 * </span><span style="color: #808080;">@param</span><span style="color: #008000;"> beanDefinitionRegistry
 </span><span style="color: #008000;">*/</span><span style="color: #000000;">
@Override
</span><span style="color: #0000ff;">public</span> <span style="color: #0000ff;">void</span><span style="color: #000000;"> registerBeanDefinitions(AnnotationMetadata annotationMetadata, BeanDefinitionRegistry beanDefinitionRegistry) {
    Map config, properties, defaultConfig </span>= binder.bind("spring.datasource", Map.<span style="color: #0000ff;">class</span>).get(); <span style="color: #008000;">//</span><span style="color: #008000;">获取所有数据源配置</span>
    sourceMap = <span style="color: #0000ff;">new</span> HashMap&lt;&gt;(); <span style="color: #008000;">//</span><span style="color: #008000;">默认配置</span>
    properties =<span style="color: #000000;"> defaultConfig;
    String typeStr </span>= evn.getProperty("spring.datasource.type"); <span style="color: #008000;">//</span><span style="color: #008000;">默认数据源类型</span>
    Class&lt;? <span style="color: #0000ff;">extends</span> DataSource&gt; clazz = getDataSourceType(typeStr); <span style="color: #008000;">//</span><span style="color: #008000;">获取数据源类型</span>
    DataSource consumerDatasource, defaultDatasource = bind(clazz, properties); <span style="color: #008000;">//</span><span style="color: #008000;">绑定默认数据源参数</span>
    List&lt;Map&gt; configs = binder.bind("spring.datasource.multi", Bindable.listOf(Map.<span style="color: #0000ff;">class</span>)).get(); <span style="color: #008000;">//</span><span style="color: #008000;">获取其他数据源配置</span>
    <span style="color: #0000ff;">for</span> (<span style="color: #0000ff;">int</span> i = 0; i &lt; configs.size(); i++) { <span style="color: #008000;">//</span><span style="color: #008000;">遍历生成其他数据源</span>
        config =<span style="color: #000000;"> configs.get(i);
        clazz </span>= getDataSourceType((String) config.get("type"<span style="color: #000000;">));
        </span><span style="color: #0000ff;">if</span> ((<span style="color: #0000ff;">boolean</span>) config.getOrDefault("extend", Boolean.TRUE)) { <span style="color: #008000;">//</span><span style="color: #008000;">获取extend字段，未定义或为true则为继承状态</span>
            properties = <span style="color: #0000ff;">new</span> HashMap(defaultConfig); <span style="color: #008000;">//</span><span style="color: #008000;">继承默认数据源配置</span>
            properties.putAll(config); <span style="color: #008000;">//</span><span style="color: #008000;">添加数据源参数</span>
        } <span style="color: #0000ff;">else</span><span style="color: #000000;"> {
            properties </span>= config; <span style="color: #008000;">//</span><span style="color: #008000;">不继承默认配置</span>

}

consumerDatasource = bind(clazz, properties); //绑定参数

sourceMap.put(config.get("key").toString(), consumerDatasource); //获取数据源的key，以便通过该key可以定位到数据源

        }

GenericBeanDefinition define = new GenericBeanDefinition(); //bean定义类

define.setBeanClass(MultiDataSource.class); //设置bean的类型，此处MultiDataSource是继承AbstractRoutingDataSource的实现类

MutablePropertyValues mpv = define.getPropertyValues(); //需要注入的参数，类似spring配置文件中的<property/>

mpv.add("defaultTargetDataSource", defaultDatasource); //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("targetDataSources", sourceMap); //添加其他数据源

beanDefinitionRegistry.registerBeanDefinition("datasource", define); //将该bean注册为datasource，不使用springboot自动生成的datasource

    }
</span><span style="color: #008000;">/**</span><span style="color: #008000;">
 * 通过字符串获取数据源class对象
 *
 * </span><span style="color: #808080;">@param</span><span style="color: #008000;"> typeStr
 * </span><span style="color: #808080;">@return</span>
 <span style="color: #008000;">*/</span>
<span style="color: #0000ff;">private</span> Class&lt;? <span style="color: #0000ff;">extends</span> DataSource&gt;<span style="color: #000000;"> getDataSourceType(String typeStr) {
    Class</span>&lt;? <span style="color: #0000ff;">extends</span> DataSource&gt;<span style="color: #000000;"> type;
    </span><span style="color: #0000ff;">try</span><span style="color: #000000;"> {
        </span><span style="color: #0000ff;">if</span> (StringUtils.hasLength(typeStr)) { <span style="color: #008000;">//</span><span style="color: #008000;">字符串不为空则通过反射获取class对象</span>
            type = (Class&lt;? <span style="color: #0000ff;">extends</span> DataSource&gt;<span style="color: #000000;">) Class.forName(typeStr);
        } </span><span style="color: #0000ff;">else</span><span style="color: #000000;"> {
            type </span>= HikariDataSource.<span style="color: #0000ff;">class</span>;  <span style="color: #008000;">//</span><span style="color: #008000;">默认为hikariCP数据源，与springboot默认数据源保持一致</span>

}

return type;

} catch (Exception e) {

throw new IllegalArgumentException("can not resolve class with type: " + typeStr); //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

        }

}
</span><span style="color: #008000;">/**</span><span style="color: #008000;">
 * 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
 *
 * </span><span style="color: #808080;">@param</span><span style="color: #008000;"> result
 * </span><span style="color: #808080;">@param</span><span style="color: #008000;"> properties
 </span><span style="color: #008000;">*/</span>
<span style="color: #0000ff;">private</span> <span style="color: #0000ff;">void</span><span style="color: #000000;"> bind(DataSource result, Map properties) {
    ConfigurationPropertySource source </span>= <span style="color: #0000ff;">new</span><span style="color: #000000;"> MapConfigurationPropertySource(properties);
    Binder binder </span>= <span style="color: #0000ff;">new</span> Binder(<span style="color: #0000ff;">new</span><span style="color: #000000;"> ConfigurationPropertySource[]{source.withAliases(aliases)});
    binder.bind(ConfigurationPropertyName.EMPTY, Bindable.ofInstance(result));  </span><span style="color: #008000;">//</span><span style="color: #008000;">将参数绑定到对象</span>

}
</span><span style="color: #0000ff;">private</span> &lt;T <span style="color: #0000ff;">extends</span> DataSource&gt; T bind(Class&lt;T&gt;<span style="color: #000000;"> clazz, Map properties) {
    ConfigurationPropertySource source </span>= <span style="color: #0000ff;">new</span><span style="color: #000000;"> MapConfigurationPropertySource(properties);
    Binder binder </span>= <span style="color: #0000ff;">new</span> Binder(<span style="color: #0000ff;">new</span><span style="color: #000000;"> ConfigurationPropertySource[]{source.withAliases(aliases)});
    </span><span style="color: #0000ff;">return</span> binder.bind(ConfigurationPropertyName.EMPTY, Bindable.of(clazz)).get(); <span style="color: #008000;">//</span><span style="color: #008000;">通过类型绑定参数并获得实例对象</span>

}
</span><span style="color: #008000;">/**</span><span style="color: #008000;">
 * </span><span style="color: #808080;">@param</span><span style="color: #008000;"> clazz
 * </span><span style="color: #808080;">@param</span><span style="color: #008000;"> sourcePath 参数路径，对应配置文件中的值，如: spring.datasource
 * </span><span style="color: #808080;">@param</span><span style="color: #008000;"> &lt;T&gt;
 * </span><span style="color: #808080;">@return</span>
 <span style="color: #008000;">*/</span>
<span style="color: #0000ff;">private</span> &lt;T <span style="color: #0000ff;">extends</span> DataSource&gt; T bind(Class&lt;T&gt;<span style="color: #000000;"> clazz, String sourcePath) {
    Map properties </span>= binder.bind(sourcePath, Map.<span style="color: #0000ff;">class</span><span style="color: #000000;">).get();
    </span><span style="color: #0000ff;">return</span><span style="color: #000000;"> bind(clazz, properties);
}

</span><span style="color: #008000;">/**</span><span style="color: #008000;">
 * EnvironmentAware接口的实现方法，通过aware的方式注入，此处是environment对象
 *
 * </span><span style="color: #808080;">@param</span><span style="color: #008000;"> environment
 </span><span style="color: #008000;">*/</span><span style="color: #000000;">
@Override
</span><span style="color: #0000ff;">public</span> <span style="color: #0000ff;">void</span><span style="color: #000000;"> setEnvironment(Environment environment) {
    </span><span style="color: #0000ff;">this</span>.evn =<span style="color: #000000;"> environment;
    binder </span>= Binder.get(evn); <span style="color: #008000;">//</span><span style="color: #008000;">绑定配置器</span>

}

}

此处放出我的配置文件application.yml ：

spring:
  datasource:
    password:
    url: jdbc:mysql://127.0.0.1:/graduation_project?useUnicode=true&characterEncoding=UTF-
    driver-class-name: com.mysql.jdbc.Driver
    username: ivan
    openMulti: true
    type: com.zaxxer.hikari.HikariDataSource
    idle-timeout:
    multi:
    - key: default1
      password:
      url: jdbc:mysql://127.0.0.1:/graduation_project?useUnicode=true&characterEncoding=UTF-
      idle-timeout:
      driver-class-name: com.mysql.jdbc.Driver
      username: ivan
      type: com.alibaba.druid.pool.DruidDataSource
    - key: gd
      password: 123456
      url: jdbc:mysql://gd.badtheway.xin:****/graduation_project?useUnicode=true&characterEncoding=UTF-
      driver-class-name: com.mysql.jdbc.Driver
      username: ivan
mybatis:
  config-location: classpath:mapper/configure.xml
  mapper-locations: classpath:mapper/*Mapper.xml

这边说明一下，spring.datasource路径下的配置即默认数据源的配置，我是为了个人美感以及方便，所以在配置多数据源时使用spring.datasource.multi这个路径，假如需要更改的话修改MultiDataSourceRegister.java里面相应的值就可以了。

最后别忘了在@SpringBootApplication加上@Import(MultiDataSourceRegister.class)

下面是我自己使用的一些切面配置，通过@MultiDataSource$DataSource注解标记需要切换数据源的类，可以通过方法体参数->方法注解->类注解实现切换数据源。供大家参考：

MultiDataSource.java：

package top.ivan.demo.springboot.mapper;

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.core.annotation.Order;

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

import org.springframework.stereotype.Component;

import org.springframework.util.StringUtils;

import java.lang.annotation.*;

import java.lang.reflect.Field;

import java.lang.reflect.Method;

import java.lang.reflect.Parameter;

import java.util.Map;

import java.util.Set;

public class MultiDataSource extends AbstractRoutingDataSource {
</span><span style="color: #0000ff;">private</span> <span style="color: #0000ff;">final</span> <span style="color: #0000ff;">static</span> ThreadLocal&lt;String&gt; DATA_SOURCE_KEY = <span style="color: #0000ff;">new</span> ThreadLocal&lt;&gt;(); <span style="color: #008000;">//</span><span style="color: #008000;">保存当前线程的数据源对应的key</span>

<span style="color: #0000ff;">private</span> Set&lt;Object&gt; keySet;  <span style="color: #008000;">//</span><span style="color: #008000;">所有数据源的key集合</span>

<span style="color: #0000ff;">private</span> <span style="color: #0000ff;">static</span> <span style="color: #0000ff;">void</span><span style="color: #000000;"> switchSource(String key) {
    DATA_SOURCE_KEY.set(key); </span><span style="color: #008000;">//</span><span style="color: #008000;">切换当先线程的key</span>

}
</span><span style="color: #0000ff;">private</span> <span style="color: #0000ff;">static</span> <span style="color: #0000ff;">void</span><span style="color: #000000;"> clear() {
    DATA_SOURCE_KEY.remove(); </span><span style="color: #008000;">//</span><span style="color: #008000;">移除key值</span>

}
</span><span style="color: #0000ff;">public</span> <span style="color: #0000ff;">static</span> Object execute(String ds, Run run) <span style="color: #0000ff;">throws</span><span style="color: #000000;"> Throwable {
    switchSource(ds);
    </span><span style="color: #0000ff;">try</span><span style="color: #000000;"> {
        </span><span style="color: #0000ff;">return</span><span style="color: #000000;"> run.run();
    } </span><span style="color: #0000ff;">finally</span><span style="color: #000000;"> {
        clear();
    }
}

</span><span style="color: #008000;">//</span><span style="color: #008000;">AbstractRoutingDataSource抽象类实现方法，即获取当前线程数据源的key</span>

@Override

protected Object determineCurrentLookupKey() {

String key = DATA_SOURCE_KEY.get();

if (!keySet.contains(key)) {

logger.info(String.format("can not found datasource by key: '%s',this session may use default datasource", key));

}

return key;

}
</span><span style="color: #008000;">/**</span><span style="color: #008000;">
 * 在获取key的集合，目的只是为了添加一些告警日志
 </span><span style="color: #008000;">*/</span><span style="color: #000000;">
@Override
</span><span style="color: #0000ff;">public</span> <span style="color: #0000ff;">void</span><span style="color: #000000;"> afterPropertiesSet() {
    </span><span style="color: #0000ff;">super</span><span style="color: #000000;">.afterPropertiesSet();
    </span><span style="color: #0000ff;">try</span><span style="color: #000000;"> {
        Field sourceMapField </span>= AbstractRoutingDataSource.<span style="color: #0000ff;">class</span>.getDeclaredField("resolvedDataSources"<span style="color: #000000;">);
        sourceMapField.setAccessible(</span><span style="color: #0000ff;">true</span><span style="color: #000000;">);
        Map</span>&lt;Object, javax.sql.DataSource&gt; sourceMap = (Map&lt;Object, javax.sql.DataSource&gt;) sourceMapField.get(<span style="color: #0000ff;">this</span><span style="color: #000000;">);
        </span><span style="color: #0000ff;">this</span>.keySet =<span style="color: #000000;"> sourceMap.keySet();
        sourceMapField.setAccessible(</span><span style="color: #0000ff;">false</span><span style="color: #000000;">);
    } </span><span style="color: #0000ff;">catch</span> (NoSuchFieldException |<span style="color: #000000;"> IllegalAccessException e) {
        e.printStackTrace();
    }

}

</span><span style="color: #0000ff;">public</span> <span style="color: #0000ff;">interface</span><span style="color: #000000;"> Run {
    Object run() </span><span style="color: #0000ff;">throws</span><span style="color: #000000;"> Throwable;
}

</span><span style="color: #008000;">/**</span><span style="color: #008000;">
 * 用于获取AOP切点及数据源key的注解
 </span><span style="color: #008000;">*/</span><span style="color: #000000;">
@Target({ElementType.METHOD, ElementType.TYPE, ElementType.PARAMETER})
@Retention(RetentionPolicy.RUNTIME)
@Documented
</span><span style="color: #0000ff;">public</span> @<span style="color: #0000ff;">interface</span><span style="color: #000000;"> DataSource {
    String value() </span><span style="color: #0000ff;">default</span> ""; <span style="color: #008000;">//</span><span style="color: #008000;">该值即key值</span>

}
</span><span style="color: #008000;">/**</span><span style="color: #008000;">
 * 声明切面
 </span><span style="color: #008000;">*/</span><span style="color: #000000;">
@Component
@Aspect
@Order(</span>-10)  <span style="color: #008000;">//</span><span style="color: #008000;">使该切面在事务之前执行</span>
<span style="color: #0000ff;">public</span> <span style="color: #0000ff;">static</span> <span style="color: #0000ff;">class</span><span style="color: #000000;"> DataSourceSwitchInterceptor {

    </span><span style="color: #008000;">/**</span><span style="color: #008000;">
     * 扫描所有含有@MultiDataSource$DataSource注解的类
     </span><span style="color: #008000;">*/</span><span style="color: #000000;">
    @Pointcut(</span>"@within(top.ivan.demo.springboot.mapper.MultiDataSource.DataSource)"<span style="color: #000000;">)
    </span><span style="color: #0000ff;">public</span> <span style="color: #0000ff;">void</span><span style="color: #000000;"> switchDataSource() {
    }

    </span><span style="color: #008000;">/**</span><span style="color: #008000;">
     * 使用around方式监控
     * </span><span style="color: #808080;">@param</span><span style="color: #008000;"> point
     * </span><span style="color: #808080;">@return</span><span style="color: #008000;">
     * </span><span style="color: #808080;">@throws</span><span style="color: #008000;"> Throwable
     </span><span style="color: #008000;">*/</span><span style="color: #000000;">
    @Around(</span>"switchDataSource()"<span style="color: #000000;">)
    </span><span style="color: #0000ff;">public</span> Object switchByMethod(ProceedingJoinPoint point) <span style="color: #0000ff;">throws</span><span style="color: #000000;"> Throwable {
        Method method </span>= getMethodByPoint(point); <span style="color: #008000;">//</span><span style="color: #008000;">获取执行方法</span>
        Parameter[] params = method.getParameters(); <span style="color: #008000;">//</span><span style="color: #008000;">获取执行参数</span>

Parameter parameter;

String source = null;

boolean isDynamic = false;

for (int i = params.length - 1; i >= 0; i--) { //扫描是否有参数带有@DataSource注解

parameter = params[i];

if (parameter.getAnnotation(DataSource.class) != null && point.getArgs()[i] instanceof String) {

source = (String) point.getArgs()[i]; //key值即该参数的值，要求该参数必须为String类型

isDynamic = true;

break;

}

}

if (!isDynamic) { //不存在参数带有Datasource注解

DataSource dataSource = method.getAnnotation(DataSource.class); //获取方法的@DataSource注解

if (null == dataSource || !StringUtils.hasLength(dataSource.value())) { //方法不含有注解

dataSource = method.getDeclaringClass().getAnnotation(DataSource.class); //获取类级别的@DataSource注解

                }

if (null != dataSource) {

source = dataSource.value(); //设置key值

                }

}

return persistBySource(source, point); //继续执行该方法

        }
    </span><span style="color: #0000ff;">private</span> Object persistBySource(String source, ProceedingJoinPoint point) <span style="color: #0000ff;">throws</span><span style="color: #000000;"> Throwable {
        </span><span style="color: #0000ff;">try</span><span style="color: #000000;"> {
            switchSource(source); </span><span style="color: #008000;">//</span><span style="color: #008000;">切换数据源</span>
            <span style="color: #0000ff;">return</span> point.proceed(); <span style="color: #008000;">//</span><span style="color: #008000;">执行</span>
        } <span style="color: #0000ff;">finally</span><span style="color: #000000;"> {
            clear(); </span><span style="color: #008000;">//</span><span style="color: #008000;">清空key值</span>

}

}
    </span><span style="color: #0000ff;">private</span><span style="color: #000000;"> Method getMethodByPoint(ProceedingJoinPoint point) {
        MethodSignature methodSignature </span>=<span style="color: #000000;"> (MethodSignature) point.getSignature();
        </span><span style="color: #0000ff;">return</span><span style="color: #000000;"> methodSignature.getMethod();
    }
}

}

示例：

package top.ivan.demo.springboot.mapper;

import org.apache.ibatis.annotations.Mapper;

import org.apache.ibatis.annotations.Param;

import top.ivan.demo.springboot.pojo.ProductPreview;

import java.util.List;

@Mapper

@MultiDataSource.DataSource("ds1")

public interface PreviewMapper {
</span><span style="color: #008000;">//</span><span style="color: #008000;">使用ds的值作为key</span>
List&lt;ProductPreview&gt; getList(@Param("start") <span style="color: #0000ff;">int</span> start, @Param("count") <span style="color: #0000ff;">int</span><span style="color: #000000;"> count, @MultiDataSource.DataSource String ds);

</span><span style="color: #008000;">//</span><span style="color: #008000;">使用“ds2”作为key</span>
@MultiDataSource.DataSource("ds2"<span style="color: #000000;">)
List</span>&lt;ProductPreview&gt; getList2(@Param("start") <span style="color: #0000ff;">int</span> start, @Param("count") <span style="color: #0000ff;">int</span><span style="color: #000000;"> count);

</span><span style="color: #008000;">//</span><span style="color: #008000;">使用“ds1”作为key</span>
List&lt;ProductPreview&gt; getList3(@Param("start") <span style="color: #0000ff;">int</span> start, @Param("count") <span style="color: #0000ff;">int</span><span style="color: #000000;"> count);

}

这几天刚接触springboot，还处于小白的状态，假如有什么问题的话欢迎大家指教

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附上源码文件: https://files.cnblogs.com/files/badtheway/springboot.zip

原文地址：https://www.cnblogs.com/badtheway/p/9061065.html