理解spring動(dòng)態(tài)切換數(shù)據(jù)源，需要對(duì)spring具有一定的了解

工作中經(jīng)常遇到讀寫分離，數(shù)據(jù)源切換的問題，那么以下是本作者實(shí)際工作中編寫的代碼 ?與大家分享一下！

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1.定義注解?DataSource?

package com.gomecar.index.datasource;import java.lang.annotation.ElementType; import java.lang.annotation.Retention; import java.lang.annotation.RetentionPolicy; import java.lang.annotation.Target;/*** 數(shù)據(jù)源切換注解* @author xiaotian**/ @Retention(RetentionPolicy.RUNTIME) @Target({ElementType.TYPE,ElementType.METHOD}) public @interface DataSource {String value() default "read";}

2. 定義切面DataSourceAspect

package com.gomecar.index.datasource;import java.lang.reflect.Method; import org.apache.log4j.Logger; import org.aspectj.lang.JoinPoint; import org.aspectj.lang.annotation.Aspect; import org.aspectj.lang.reflect.MethodSignature;/*** 用于數(shù)據(jù)庫讀寫分離的切面* @author xiaotian**/ @Aspect public class DataSourceAspect {//日志private Logger logger = Logger.getLogger(this.getClass());/*** 攔截目標(biāo)方法，獲取由@DataSource指定的數(shù)據(jù)源標(biāo)識(shí)，設(shè)置到線程存儲(chǔ)中以便切換數(shù)據(jù)源** @param point* @throws Exception*/public void intercept(JoinPoint point) throws Exception {Class<?> target = point.getTarget().getClass();MethodSignature signature = (MethodSignature) point.getSignature();for (Class<?> clazz : target.getInterfaces()) {resolveDataSource(clazz, signature.getMethod());}resolveDataSource(target, signature.getMethod());}/*** 提取目標(biāo)對(duì)象方法注解和類型注解中的數(shù)據(jù)源標(biāo)識(shí)** @param clazz* @param method*/private void resolveDataSource(Class<?> clazz, Method method) {try {Class<?>[] types = method.getParameterTypes();// 默認(rèn)使用類型注解dataSourcePointcutdataSourcePointcutif (clazz.isAnnotationPresent(DataSource.class)) {DataSource source = clazz.getAnnotation(DataSource.class);DynamicDataSourceHolder.putDataSource(source.value());}// 方法注解可以覆蓋類型注解Method m = clazz.getMethod(method.getName(), types);if (m != null && m.isAnnotationPresent(DataSource.class)) {DataSource source = m.getAnnotation(DataSource.class);DynamicDataSourceHolder.putDataSource(source.value());}} catch (Exception e) {logger.error("切換數(shù)據(jù)源error", e);}}//通知public void before(JoinPoint point){Object target = point.getTarget();String method = point.getSignature().getName();//反射獲取接口Class<?>[] classz = target.getClass().getInterfaces();//獲取返回值類型 Class<?>[] parameterTypes = ((MethodSignature) point.getSignature()).getMethod().getParameterTypes();try {//獲取方法Method m = classz[0].getMethod(method, parameterTypes);//根據(jù)方法上注解 獲取只讀數(shù)據(jù)庫連接池 或者只寫數(shù)據(jù)庫連接池if (m != null && m.isAnnotationPresent(DataSource.class)) {//根據(jù)注解值獲取數(shù)據(jù)庫連接池DataSource data = m.getAnnotation(DataSource.class);DynamicDataSourceHolder.putDataSource(data.value());System.out.println(data.value());}} catch (Exception e) {// TODO: handle exception }} }

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3.獲取動(dòng)態(tài)數(shù)據(jù)源DynamicDataSource

package com.gomecar.index.datasource;import org.springframework.jdbc.datasource.lookup.AbstractRoutingDataSource; /*** 動(dòng)態(tài)獲取數(shù)據(jù)源* @author xiaotian**/ public class DynamicDataSource extends AbstractRoutingDataSource {@Overrideprotected Object determineCurrentLookupKey() {return DynamicDataSourceHolder.getDataSouce();}}

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4.數(shù)據(jù)源持有者DynamicDataSourceHolder

package com.gomecar.index.datasource; /*** 數(shù)據(jù)庫連接池 持有者* 將數(shù)據(jù)庫連接綁定到當(dāng)前線程* @author xiaotian**/ public class DynamicDataSourceHolder {//綁定當(dāng)前線程public static final ThreadLocal<String> holder = new ThreadLocal<String>();//設(shè)置數(shù)據(jù)源public static void putDataSource(String name) {holder.set(name);}//獲取數(shù)據(jù)源public static String getDataSouce() {return holder.get();} }

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轉(zhuǎn)載于:https://www.cnblogs.com/shoutn/p/7800916.html

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