springboot多数据源配置

不是什么稀罕玩意，一百度一大堆，只是为了方便自己copy代码。

关于AbstractRoutingDataSource，看源码可以知道，这个是用来连数据库的，配置不同的数据库连接，根据不同的key选择不同的链接。

/*
 * Copyright 2002-2017 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.jdbc.datasource.lookup;

import java.sql.Connection;
import java.sql.SQLException;
import java.util.HashMap;
import java.util.Map;

import javax.sql.DataSource;

import org.springframework.beans.factory.InitializingBean;
import org.springframework.jdbc.datasource.AbstractDataSource;
import org.springframework.lang.Nullable;
import org.springframework.util.Assert;

/**
 * Abstract {@link javax.sql.DataSource} implementation that routes {@link #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.
 *
 * @author Juergen Hoeller
 * @since 2.0.1
 * @see #setTargetDataSources
 * @see #setDefaultTargetDataSource
 * @see #determineCurrentLookupKey()
 */
public abstract class AbstractRoutingDataSource extends AbstractDataSource implements InitializingBean {

	@Nullable
	private Map<Object, Object> targetDataSources;

	@Nullable
	private Object defaultTargetDataSource;

	private boolean lenientFallback = true;

	private DataSourceLookup dataSourceLookup = new JndiDataSourceLookup();

	@Nullable
	private Map<Object, DataSource> resolvedDataSources;

	@Nullable
	private DataSource resolvedDefaultDataSource;


	/**
	 * Specify the map of target DataSources, with the lookup key as key.
	 * The mapped value can either be a corresponding {@link javax.sql.DataSource}
	 * instance or a data source name String (to be resolved via a
	 * {@link #setDataSourceLookup DataSourceLookup}).
	 * <p>The key can be of arbitrary type; this class implements the
	 * generic lookup process only. The concrete key representation will
	 * be handled by {@link #resolveSpecifiedLookupKey(Object)} and
	 * {@link #determineCurrentLookupKey()}.
	 */
	public void setTargetDataSources(Map<Object, Object> targetDataSources) {
		this.targetDataSources = targetDataSources;
	}

	/**
	 * Specify the default target DataSource, if any.
	 * <p>The mapped value can either be a corresponding {@link javax.sql.DataSource}
	 * instance or a data source name String (to be resolved via a
	 * {@link #setDataSourceLookup DataSourceLookup}).
	 * <p>This DataSource will be used as target if none of the keyed
	 * {@link #setTargetDataSources targetDataSources} match the
	 * {@link #determineCurrentLookupKey()} current lookup key.
	 */
	public void setDefaultTargetDataSource(Object defaultTargetDataSource) {
		this.defaultTargetDataSource = defaultTargetDataSource;
	}

	/**
	 * Specify whether to apply a lenient fallback to the default DataSource
	 * if no specific DataSource could be found for the current lookup key.
	 * <p>Default is "true", accepting lookup keys without a corresponding entry
	 * in the target DataSource map - simply falling back to the default DataSource
	 * in that case.
	 * <p>Switch this flag to "false" if you would prefer the fallback to only apply
	 * if the lookup key was {@code null}. Lookup keys without a DataSource
	 * entry will then lead to an IllegalStateException.
	 * @see #setTargetDataSources
	 * @see #setDefaultTargetDataSource
	 * @see #determineCurrentLookupKey()
	 */
	public void setLenientFallback(boolean lenientFallback) {
		this.lenientFallback = lenientFallback;
	}

	/**
	 * Set the DataSourceLookup implementation to use for resolving data source
	 * name Strings in the {@link #setTargetDataSources targetDataSources} map.
	 * <p>Default is a {@link JndiDataSourceLookup}, allowing the JNDI names
	 * of application server DataSources to be specified directly.
	 */
	public void setDataSourceLookup(@Nullable DataSourceLookup dataSourceLookup) {
		this.dataSourceLookup = (dataSourceLookup != null ? dataSourceLookup : new JndiDataSourceLookup());
	}


	@Override
	public void afterPropertiesSet() {
		if (this.targetDataSources == null) {
			throw new IllegalArgumentException("Property 'targetDataSources' is required");
		}
		this.resolvedDataSources = new HashMap<>(this.targetDataSources.size());
		this.targetDataSources.forEach((key, value) -> {
			Object lookupKey = resolveSpecifiedLookupKey(key);
			DataSource dataSource = resolveSpecifiedDataSource(value);
			this.resolvedDataSources.put(lookupKey, dataSource);
		});
		if (this.defaultTargetDataSource != null) {
			this.resolvedDefaultDataSource = resolveSpecifiedDataSource(this.defaultTargetDataSource);
		}
	}

	/**
	 * Resolve the given lookup key object, as specified in the
	 * {@link #setTargetDataSources targetDataSources} map, into
	 * the actual lookup key to be used for matching with the
	 * {@link #determineCurrentLookupKey() current lookup key}.
	 * <p>The default implementation simply returns the given key as-is.
	 * @param lookupKey the lookup key object as specified by the user
	 * @return the lookup key as needed for matching
	 */
	protected Object resolveSpecifiedLookupKey(Object lookupKey) {
		return lookupKey;
	}

	/**
	 * Resolve the specified data source object into a DataSource instance.
	 * <p>The default implementation handles DataSource instances and data source
	 * names (to be resolved via a {@link #setDataSourceLookup DataSourceLookup}).
	 * @param dataSource the data source value object as specified in the
	 * {@link #setTargetDataSources targetDataSources} map
	 * @return the resolved DataSource (never {@code null})
	 * @throws IllegalArgumentException in case of an unsupported value type
	 */
	protected DataSource resolveSpecifiedDataSource(Object dataSource) throws IllegalArgumentException {
		if (dataSource instanceof DataSource) {
			return (DataSource) dataSource;
		}
		else if (dataSource instanceof String) {
			return this.dataSourceLookup.getDataSource((String) dataSource);
		}
		else {
			throw new IllegalArgumentException(
					"Illegal data source value - only [javax.sql.DataSource] and String supported: " + dataSource);
		}
	}


	@Override
	public Connection getConnection() throws SQLException {
		return determineTargetDataSource().getConnection();
	}

	@Override
	public Connection getConnection(String username, String password) throws SQLException {
		return determineTargetDataSource().getConnection(username, password);
	}

	@Override
	@SuppressWarnings("unchecked")
	public <T> T unwrap(Class<T> iface) throws SQLException {
		if (iface.isInstance(this)) {
			return (T) this;
		}
		return determineTargetDataSource().unwrap(iface);
	}

	@Override
	public boolean isWrapperFor(Class<?> iface) throws SQLException {
		return (iface.isInstance(this) || determineTargetDataSource().isWrapperFor(iface));
	}

	/**
	 * Retrieve the current target DataSource. Determines the
	 * {@link #determineCurrentLookupKey() current lookup key}, performs
	 * a lookup in the {@link #setTargetDataSources targetDataSources} map,
	 * falls back to the specified
	 * {@link #setDefaultTargetDataSource default target DataSource} if necessary.
	 * @see #determineCurrentLookupKey()
	 */
	protected DataSource determineTargetDataSource() {
		Assert.notNull(this.resolvedDataSources, "DataSource router not initialized");
		Object lookupKey = determineCurrentLookupKey();
		DataSource dataSource = this.resolvedDataSources.get(lookupKey);
		if (dataSource == null && (this.lenientFallback || lookupKey == null)) {
			dataSource = this.resolvedDefaultDataSource;
		}
		if (dataSource == null) {
			throw new IllegalStateException("Cannot determine target DataSource for lookup key [" + lookupKey + "]");
		}
		return dataSource;
	}

	/**
	 * Determine the current lookup key. This will typically be
	 * implemented to check a thread-bound transaction context.
	 * <p>Allows for arbitrary keys. The returned key needs
	 * to match the stored lookup key type, as resolved by the
	 * {@link #resolveSpecifiedLookupKey} method.
	 */
	@Nullable
	protected abstract Object determineCurrentLookupKey();

}

主题思想就是扩展AbstractRoutingDataSource，配置好以后通过aop决定请求使用哪个数据源

所以首先，扩展AbstractRoutingDataSource

public class DynamicDataSource extends AbstractRoutingDataSource {
    //这边定义了一个和线程绑定的ThreadLocal变量，用于存放需要使用的数据源的名称
    private static final ThreadLocal<String> dataSourceNameHolder = new ThreadLocal<>();

    public DynamicDataSource(DruidDataSource defaultTargetDataSource, Map<Object, Object> targetDataSources) {
        super.setDefaultTargetDataSource(defaultTargetDataSource);
        super.setTargetDataSources(targetDataSources);
        super.afterPropertiesSet();
    }

    @Override
    //重写了AbstractRoutingDataSource的determineCurrentLookupKey方法
    protected Object determineCurrentLookupKey() {
        return getDataSource();
    }

    public static void setDataSource(String dataSource) {
        dataSourceNameHolder.set(dataSource);
    }

    public static String getDataSource() {
        return dataSourceNameHolder.get();
    }

    public static void clearDataSource() {
        dataSourceNameHolder.remove();
    }
}

配置类（常量不再贴了）

@Configuration
public class DynamicDataSourceConfig {
    @Bean
    @ConfigurationProperties("spring.datasource.his")
    public DruidDataSource hisDataSource(){
        return DruidDataSourceBuilder.create().build();
    }

    @Bean
    @ConfigurationProperties("spring.datasource.app")
    public DruidDataSource appDataSource(){
        return DruidDataSourceBuilder.create().build();
    }

    @Bean
    @Primary
    @DependsOn(value = {"hisDataSource","appDataSource"})
    public DynamicDataSource dataSource(DruidDataSource hisDataSource,DruidDataSource appDataSource) {
        Map<Object, Object> targetDataSources = new HashMap<>();
        targetDataSources.put(DataSourceNames.HIS, hisDataSource);
        targetDataSources.put(DataSourceNames.APP,  appDataSource);
        return new DynamicDataSource(hisDataSource, targetDataSources);
    }
}

注解

@Target({ElementType.METHOD, ElementType.TYPE})
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface TargetDataSource {
    String name() default DataSourceNames.HIS;

}

切面

@Aspect
@Component
public class DataSourceAspect implements Ordered {

    @Pointcut("@annotation(com.digihealth.vueforhis.datasource.TargetDataSource)")
    public void dataSourcePointCut() {

    }

    @Around("dataSourcePointCut()")
    public Object around(ProceedingJoinPoint point) throws Throwable {
        MethodSignature signature = (MethodSignature) point.getSignature();
        Method method = signature.getMethod();

        TargetDataSource ds = method.getAnnotation(TargetDataSource.class);
        //如果未指定数据源就使用第一个数据源
        if(ds == null){
            DynamicDataSource.setDataSource(DataSourceNames.HIS);
        }else {
            DynamicDataSource.setDataSource(ds.name());
        }
        try {
            return point.proceed();
        } finally {
            DynamicDataSource.clearDataSource();
        }
    }

    @Override
    public int getOrder() {
        return 1;
    }
}

使用

@Mapper
public interface TestDao {
    @TargetDataSource(name = DataSourceNames.HIS)
    String his();
    @TargetDataSource(name = DataSourceNames.APP)
    String app();
}

相关依赖

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-aop</artifactId>
        </dependency>

        <!-- https://mvnrepository.com/artifact/com.alibaba/druid -->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid</artifactId>
            <version>1.1.10</version>
        </dependency>

        <!-- https://mvnrepository.com/artifact/com.alibaba/druid-spring-boot-starter -->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid-spring-boot-starter</artifactId>
            <version>1.1.10</version>
        </dependency>

 

本文地址：https://blog.csdn.net/haozi_rou/article/details/111933790