由于springboot2更新了綁定參數的api,部分springboot1用于綁定的工具類如RelaxedPropertyResolver已經無法在新版本中使用。本文實作參考了https://blog.csdn.net/catoop/article/details/50575038這篇文章,大緻思路是一緻的,如果需要詳細實作可以參考。都是通過AbstractRoutingDataSource實作動态資料源的切換,以前我用spring配置多資料源的時候就是通過它實作的,有興趣的可以了解下其原理,這裡就不多贅述了。
廢話不多說了,先上資料源注冊工具類,springboot2與1的主要差別也就在這:
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;">由于部分資料源配置不同,是以在此處添加别名,避免切換資料源出現某些參數無法注入的情況</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(也可以了解為配置檔案的擷取工具)</span>
<span style="color: #0000ff;">private</span> Map<String, DataSource> sourceMap; <span style="color: #008000;">//</span><span style="color: #008000;">資料源清單</span>
<span style="color: #0000ff;">private</span> Binder binder; <span style="color: #008000;">//</span><span style="color: #008000;">參數綁定工具</span>
<span style="color: #008000;">/**</span><span style="color: #008000;">
* ImportBeanDefinitionRegistrar接口的實作方法,通過該方法可以按照自己的方式注冊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;">擷取所有資料源配置</span>
sourceMap = <span style="color: #0000ff;">new</span> HashMap<>(); <span style="color: #008000;">//</span><span style="color: #008000;">預設配置</span>
properties =<span style="color: #000000;"> defaultConfig;
String typeStr </span>= evn.getProperty("spring.datasource.type"); <span style="color: #008000;">//</span><span style="color: #008000;">預設資料源類型</span>
Class<? <span style="color: #0000ff;">extends</span> DataSource> clazz = getDataSourceType(typeStr); <span style="color: #008000;">//</span><span style="color: #008000;">擷取資料源類型</span>
DataSource consumerDatasource, defaultDatasource = bind(clazz, properties); <span style="color: #008000;">//</span><span style="color: #008000;">綁定預設資料源參數</span>
List<Map> 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;">擷取其他資料源配置</span>
<span style="color: #0000ff;">for</span> (<span style="color: #0000ff;">int</span> i = 0; i < configs.size(); i++) { <span style="color: #008000;">//</span><span style="color: #008000;">周遊生成其他資料源</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;">擷取extend字段,未定義或為true則為繼承狀态</span>
properties = <span style="color: #0000ff;">new</span> HashMap(defaultConfig); <span style="color: #008000;">//</span><span style="color: #008000;">繼承預設資料源配置</span>
properties.putAll(config); <span style="color: #008000;">//</span><span style="color: #008000;">添加資料源參數</span>
} <span style="color: #0000ff;">else</span><span style="color: #000000;"> {
properties </span>= config; <span style="color: #008000;">//</span><span style="color: #008000;">不繼承預設配置</span>
}
consumerDatasource = bind(clazz, properties); //綁定參數
sourceMap.put(config.get("key").toString(), consumerDatasource); //擷取資料源的key,以便通過該key可以定位到資料源
}
GenericBeanDefinition define = new GenericBeanDefinition(); //bean定義類
define.setBeanClass(MultiDataSource.class); //設定bean的類型,此處MultiDataSource是繼承AbstractRoutingDataSource的實作類
MutablePropertyValues mpv = define.getPropertyValues(); //需要注入的參數,類似spring配置檔案中的<property/>
mpv.add("defaultTargetDataSource", defaultDatasource); //添加預設資料源,避免key不存在的情況沒有資料源可用
mpv.add("targetDataSources", sourceMap); //添加其他資料源
beanDefinitionRegistry.registerBeanDefinition("datasource", define); //将該bean注冊為datasource,不使用springboot自動生成的datasource
}
</span><span style="color: #008000;">/**</span><span style="color: #008000;">
* 通過字元串擷取資料源class對象
*
* </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<? <span style="color: #0000ff;">extends</span> DataSource><span style="color: #000000;"> getDataSourceType(String typeStr) {
Class</span><? <span style="color: #0000ff;">extends</span> DataSource><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;">字元串不為空則通過反射擷取class對象</span>
type = (Class<? <span style="color: #0000ff;">extends</span> DataSource><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;">預設為hikariCP資料源,與springboot預設資料源保持一緻</span>
}
return type;
} catch (Exception e) {
throw new IllegalArgumentException("can not resolve class with type: " + typeStr); //無法通過反射擷取class對象的情況則抛出異常,該情況一般是寫錯了,是以此次抛出一個runtimeexception
}
}
</span><span style="color: #008000;">/**</span><span style="color: #008000;">
* 綁定參數,以下三個方法都是參考DataSourceBuilder的bind方法實作的,目的是盡量保證我們自己添加的資料源構造過程與springboot保持一緻
*
* </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;">将參數綁定到對象</span>
}
</span><span style="color: #0000ff;">private</span> <T <span style="color: #0000ff;">extends</span> DataSource> T bind(Class<T><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;">通過類型綁定參數并獲得執行個體對象</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 參數路徑,對應配置檔案中的值,如: spring.datasource
* </span><span style="color: #808080;">@param</span><span style="color: #008000;"> <T>
* </span><span style="color: #808080;">@return</span>
<span style="color: #008000;">*/</span>
<span style="color: #0000ff;">private</span> <T <span style="color: #0000ff;">extends</span> DataSource> T bind(Class<T><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接口的實作方法,通過aware的方式注入,此處是environment對象
*
* </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;">綁定配置器</span>
}
}

此處放出我的配置檔案application.yml :

spring:
datasource:
password: 123456
url: jdbc:mysql://127.0.0.1:3306/graduation_project?useUnicode=true&characterEncoding=UTF-8
driver-class-name: com.mysql.jdbc.Driver
username: ivan
openMulti: true
type: com.zaxxer.hikari.HikariDataSource
idle-timeout: 30000
multi:
- key: default1
password: 123456
url: jdbc:mysql://127.0.0.1:3306/graduation_project?useUnicode=true&characterEncoding=UTF-8
idle-timeout: 20000
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-8
driver-class-name: com.mysql.jdbc.Driver
username: ivan
mybatis:
config-location: classpath:mapper/configure.xml
mapper-locations: classpath:mapper/*Mapper.xml

這邊說明一下,spring.datasource路徑下的配置即預設資料源的配置,我是為了個人美感以及友善,是以在配置多資料源時使用spring.datasource.multi這個路徑,假如需要更改的話修改MultiDataSourceRegister.java裡面相應的值就可以了。
最後别忘了在@SpringBootApplication加上@Import(MultiDataSourceRegister.class)
下面是我自己使用的一些切面配置,通過@MultiDataSource$DataSource注解标記需要切換資料源的類,可以通過方法體參數->方法注解->類注解實作切換資料源。供大家參考:
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<String> DATA_SOURCE_KEY = <span style="color: #0000ff;">new</span> ThreadLocal<>(); <span style="color: #008000;">//</span><span style="color: #008000;">儲存目前線程的資料源對應的key</span>
<span style="color: #0000ff;">private</span> Set<Object> keySet; <span style="color: #008000;">//</span><span style="color: #008000;">所有資料源的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;">切換當先線程的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抽象類實作方法,即擷取目前線程資料源的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;">
* 在擷取key的集合,目的隻是為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><Object, javax.sql.DataSource> sourceMap = (Map<Object, javax.sql.DataSource>) 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;">
* 用于擷取AOP切點及資料源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;">該值即key值</span>
}
</span><span style="color: #008000;">/**</span><span style="color: #008000;">
* 聲明切面
</span><span style="color: #008000;">*/</span><span style="color: #000000;">
@Component
@Aspect
@Order(</span>-10) <span style="color: #008000;">//</span><span style="color: #008000;">使該切面在事務之前執行</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;">
* 掃描所有含有@MultiDataSource$DataSource注解的類
</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方式監控
* </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;">擷取執行方法</span>
Parameter[] params = method.getParameters(); <span style="color: #008000;">//</span><span style="color: #008000;">擷取執行參數</span>
Parameter parameter;
String source = null;
boolean isDynamic = false;
for (int i = params.length - 1; i >= 0; i--) { //掃描是否有參數帶有@DataSource注解
parameter = params[i];
if (parameter.getAnnotation(DataSource.class) != null && point.getArgs()[i] instanceof String) {
source = (String) point.getArgs()[i]; //key值即該參數的值,要求該參數必須為String類型
isDynamic = true;
break;
}
}
if (!isDynamic) { //不存在參數帶有Datasource注解
DataSource dataSource = method.getAnnotation(DataSource.class); //擷取方法的@DataSource注解
if (null == dataSource || !StringUtils.hasLength(dataSource.value())) { //方法不含有注解
dataSource = method.getDeclaringClass().getAnnotation(DataSource.class); //擷取類級别的@DataSource注解
}
if (null != dataSource) {
source = dataSource.value(); //設定key值
}
}
return persistBySource(source, point); //繼續執行該方法
}
</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;">切換資料源</span>
<span style="color: #0000ff;">return</span> point.proceed(); <span style="color: #008000;">//</span><span style="color: #008000;">執行</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的值作為key</span>
List<ProductPreview> 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”作為key</span>
@MultiDataSource.DataSource("ds2"<span style="color: #000000;">)
List</span><ProductPreview> 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”作為key</span>
List<ProductPreview> getList3(@Param("start") <span style="color: #0000ff;">int</span> start, @Param("count") <span style="color: #0000ff;">int</span><span style="color: #000000;"> count);
}

這幾天剛接觸springboot,還處于小白的狀态,假如有什麼問題的話歡迎大家指教
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附上源碼檔案: https://files.cnblogs.com/files/badtheway/springboot.zip
原文位址:https://www.cnblogs.com/badtheway/p/9061065.html