Spring4+dbcp+mysql6.06使用注解实现动态切库（不支持跨库事务）

maven依赖

<?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.mutil.transaction</groupId>    <artifactId>transaction</artifactId>    <version>0.0.1-SNAPSHOT</version>    <packaging>jar</packaging>    <name>transaction</name>    <description>Demo project for Spring Boot</description>    <parent>        <groupId>org.springframework.boot</groupId>        <artifactId>spring-boot-starter-parent</artifactId>        <version>1.5.9.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>    </properties>    <dependencies>        <dependency>            <groupId>org.springframework.boot</groupId>            <artifactId>spring-boot-starter-aop</artifactId>        </dependency>        <dependency>            <groupId>org.springframework</groupId>            <artifactId>spring-jdbc</artifactId>        </dependency>        <dependency>            <groupId>mysql</groupId>            <artifactId>mysql-connector-java</artifactId>            <version>6.0.6</version>        </dependency>        <dependency>            <groupId>org.springframework.boot</groupId>            <artifactId>spring-boot-starter-test</artifactId>            <scope>test</scope>        </dependency>        <dependency>            <groupId>commons-dbcp</groupId>            <artifactId>commons-dbcp</artifactId>            <version>1.4</version>        </dependency>    </dependencies>    <build>        <plugins>            <plugin>                <groupId>org.springframework.boot</groupId>                <artifactId>spring-boot-maven-plugin</artifactId>            </plugin>        </plugins>    </build></project>

db.properties

spring.datasource.sakila.url=jdbc:mysql://localhost:3306/sakila?useUnicode=true&characterEncoding=UTF-8&useJDBCCompliantTimezoneShift=true&useLegacyDatetimeCode=false&serverTimezone=UTC&useSSL=truespring.datasource.sakila.username=rootspring.datasource.sakila.password=rootspring.datasource.sakila.driverClassName=com.mysql.cj.jdbc.Driverspring.datasource.sakila.initialSize=1spring.datasource.sakila.maxIdle=2spring.datasource.sakila.minIdle=1spring.datasource.library.url=jdbc:mysql://localhost:3306/library?useUnicode=true&characterEncoding=UTF-8&useJDBCCompliantTimezoneShift=true&useLegacyDatetimeCode=false&serverTimezone=UTC&useSSL=truespring.datasource.library.username=rootspring.datasource.library.password=rootspring.datasource.library.driverClassName=com.mysql.cj.jdbc.Driverspring.datasource.library.initialSize=1spring.datasource.library.maxIdle=2spring.datasource.library.minIdle=1spring.datasource.defalut.defaultDataSourceName=libraryDataSource

DBConfig2 ：配置数据源、DataSourceTransactionManager、JdbcTemplate

package com.mutil.transaction.config;import javax.sql.DataSource;import org.springframework.beans.factory.annotation.Qualifier;import org.springframework.boot.autoconfigure.jdbc.DataSourceBuilder;import org.springframework.boot.context.properties.ConfigurationProperties;import org.springframework.context.annotation.Bean;import org.springframework.context.annotation.Configuration;import org.springframework.context.annotation.Primary;import org.springframework.context.annotation.PropertySource;import org.springframework.jdbc.core.JdbcTemplate;import org.springframework.jdbc.datasource.DataSourceTransactionManager;/** * Created by WuTing on 2017/12/5. */@Configuration@PropertySource("classpath:db.properties")public class DBConfig2 {    @Bean("libraryDataSource")    @ConfigurationProperties(prefix = "spring.datasource.library")    @Primary    public DataSource libraryDataSource() {        return DataSourceBuilder.create().build();    }    @Bean("sakilaDataSource")    @ConfigurationProperties(prefix = "spring.datasource.sakila")    public DataSource sakilaDataSource() {        return DataSourceBuilder.create().build();    }    @Bean("dataSource")    public DynamicDataSource dataSource() {        return new DynamicDataSource("libraryDataSource");    }    @Bean("jdbcTemplate")    public JdbcTemplate jdbcTemplate(@Qualifier("dataSource") DynamicDataSource dataSource) {        return new JdbcTemplate(dataSource);    }    @Bean("transactionManager")    public DataSourceTransactionManager transactionManager(@Qualifier("dataSource") DataSource dataSource) {        return new DataSourceTransactionManager(dataSource);    }}

DynamicDataSource：继承了AbstractRoutingDataSource，设置多个数据源，将数据源交给Spring控制

package com.mutil.transaction.config;import java.util.List;import java.util.Map;import java.util.stream.Collectors;import javax.sql.DataSource;import org.springframework.jdbc.datasource.lookup.AbstractRoutingDataSource;import com.atomikos.jdbc.AtomikosDataSourceBean;/** * Created by WuTing on 2017/12/5. */public class DynamicDataSource extends AbstractRoutingDataSource {    public DynamicDataSource(String defaultDataSourceName) {        Map<Object, Object> dataSourcs = SpringContextUtil.getBeans(DataSource.class, DynamicDataSource.class);        List dataSourceIds = dataSourcs.keySet().stream().collect(Collectors.toList());        DataSourceContextHolder.dataSourceIds.addAll(dataSourceIds);        this.setTargetDataSources(dataSourcs);        this.setDefaultTargetDataSource(dataSourcs.get(defaultDataSourceName));    }    @Override    protected Object determineCurrentLookupKey() {        return DataSourceContextHolder.getDataSourceType();    }}

为了使用注解方式进行动态切换数据源，需要定义一个DataSource注解，并且使用AOP方式进行数据源动态切换。DataSourceAspect 切面便是用于数据源切换。

DataSource注解：可作用于方法、class上， 用于class表明当前class的所有方法使用相同的数据源，用于方法上申明当前方法使用的数据源，当同时用于方法和class上时，用于方法上优先级较高。

package com.mutil.transaction.config;import java.lang.annotation.Documented;import java.lang.annotation.ElementType;import java.lang.annotation.Inherited;import java.lang.annotation.Retention;import java.lang.annotation.RetentionPolicy;import java.lang.annotation.Target;/** * Created by WuTing on 2017/12/5. */@Target({ElementType.METHOD, ElementType.TYPE})@Retention(RetentionPolicy.RUNTIME)@Inherited@Documentedpublic @interface DataSource {    String value();}

DataSourceAspect：用于动态切换数据源.

package com.mutil.transaction.config;import java.lang.reflect.Method;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.aspectj.lang.reflect.MethodSignature;import org.slf4j.Logger;import org.slf4j.LoggerFactory;import org.springframework.core.annotation.Order;import org.springframework.stereotype.Component;/** * Created by WuTing on 2017/12/5. */@Component@Aspect@Order(1)public class DataSourceAspect {    private static final Logger logger = LoggerFactory.getLogger(DataSourceAspect.class);    @Before(value = "execution(* com.mutil.transaction.service.*.*(..))")    public void before(JoinPoint point) {        DataSource annotation = getDataSourceAnnotation(point);        if (annotation != null) {            DataSourceContextHolder.setDataSourceType(annotation.value());            logger.debug("Set DataSource : {} > {}", annotation.value(), point.getSignature());        }    }    @After(value = "execution(* com.mutil.transaction.service.*.*(..))")    public void restoreDataSource(JoinPoint point) {        DataSource annotation = getDataSourceAnnotation(point);        if (annotation != null) {            logger.debug("Revert DataSource : {} > {}", annotation.value(), point.getSignature());        }        DataSourceContextHolder.clearDataSourceType();    }    private DataSource getDataSourceAnnotation(JoinPoint point) {        DataSource annotation = null;        Class[] parameterTypes = ((MethodSignature)point.getSignature()).getMethod().getParameterTypes();        String methodName = point.getSignature().getName();        try {            Method method = point.getTarget().getClass().getMethod(methodName, parameterTypes);            if (method.isAnnotationPresent(DataSource.class)) {                annotation = method.getAnnotation(DataSource.class);            } else {                annotation = point.getTarget().getClass().getAnnotation(DataSource.class);            }        } catch (NoSuchMethodException e) {            e.printStackTrace();        }        return annotation;    }}

DataSourceContextHolder：数据源切换实现类

package com.mutil.transaction.config;import java.util.ArrayList;import java.util.List;/** * Created by WuTing on 2017/12/5. */public class DataSourceContextHolder {    private static final ThreadLocal<String> contextHolder = new ThreadLocal<String>();    public static List<String> dataSourceIds = new ArrayList<>();    public static void setDataSourceType(String dataSourceType) {        contextHolder.set(dataSourceType);    }    public static String getDataSourceType() {        return contextHolder.get();    }    public static void clearDataSourceType() {        contextHolder.remove();    }    public static boolean containsDataSource(String dataSourceId) {        return dataSourceIds.contains(dataSourceId);    }}

项目地址：https://github.com/wutingting1993/transaction/tree/Switch-DB-Automatic/