前言：

springboot整合多数据源，大家肯定不陌生，方式不一，但是相信大家整合多数据源，如果涉及到事务，都会非常烦恼，多数据源的事务不是冲突就是失效，而如今网上千篇一律的老年博客，想找到真正解决问题的，非常少。所以我决定出来分享下可用的整合方案，而且是从头到尾的那种。

这一篇我选择的是以AOP注解的方式去进行数据源的动态切换，顺带整合jta-atomikos把烦人的事务问题解决调，持久层框架用mybatis，数据库连接池使用druid，这些在我们周围目前使用比较多，方便大家根据项目实际需求，能在这个脚手架上进行进一步的扩展（能扩展什么？也可以看看我的springboot专栏，说不定会有额外的收获）

这篇篇幅可能较长，但是跟着我全部代码流程走完，你以后就可以把这个作为多数据源+分布式事务的脚手架，以后对于多数据源相关的事务问题，对你来说就不是问题。

接下来，我们开始整合。

先看下项目目录结构，大致能了解到我们这个实战整合做了些什么。

先准备两个数据源，

创个user表用于后面使用，

CREATE TABLE `user` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `username` varchar(255) DEFAULT NULL,
  `age` int(11) DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8

pom.xml：

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <!--分布式事务-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-jta-atomikos</artifactId>
        </dependency>
        <!-- lombok -->
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.16.10</version>
        </dependency>
        <!-- springboot2.1.x版本默认的mysql-connector-java 版本比较高 8.0.x ,需要降低版本-->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>6.0.6</version>
        </dependency>
        <!--Druid连接池-->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid-spring-boot-starter</artifactId>
            <version>1.1.9</version>
        </dependency>
        <!--aop starter-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-aop</artifactId>
        </dependency>
        <!--整合mybatis-->
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>2.1.0</version>
        </dependency>
        <!--调试-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

然后是数据源的yml信息，application.yml：

server:
  port: 8077
spring:
  application:
    name: jta-dbsource
  datasource:
    druid:
      mydbone:
        url: jdbc:mysql://localhost:3306/mydbone?useUnicode=true&characterEncoding=utf-8&useSSL=false&serverTimezone=GMT%2B8&pinGlobalTxToPhysicalConnection=true&autoReconnect=true
        username: root
        password: root
        driver-class-name: com.mysql.cj.jdbc.Driver
        # 初始化时建立物理连接的个数。初始化发生在显示调用 init 方法，或者第一次 getConnection 时
        initialSize: 5
        # 最小连接池数量
        minIdle: 5
        # 最大连接池数量
        maxActive: 10
        # 获取连接时最大等待时间，单位毫秒。配置了 maxWait 之后，缺省启用公平锁，并发效率会有所下降，如果需要可以通过配置 useUnfairLock 属性为 true 使用非公平锁。
        maxWait: 60000
        # Destroy 线程会检测连接的间隔时间，如果连接空闲时间大于等于 minEvictableIdleTimeMillis 则关闭物理连接。
        timeBetweenEvictionRunsMillis: 60000
        # 连接保持空闲而不被驱逐的最小时间
        minEvictableIdleTimeMillis: 300000
        # 用来检测连接是否有效的 sql 因数据库方言而异, 例如 oracle 应该写成 SELECT 1 FROM DUAL
        validationQuery: SELECT 1
        # 建议配置为 true，不影响性能，并且保证安全性。申请连接的时候检测，如果空闲时间大于 timeBetweenEvictionRunsMillis，执行 validationQuery 检测连接是否有效。
        testWhileIdle: true
        # 申请连接时执行 validationQuery 检测连接是否有效，做了这个配置会降低性能。
        testOnBorrow: false
        # 归还连接时执行 validationQuery 检测连接是否有效，做了这个配置会降低性能。
        testOnReturn: false
        # 是否自动回收超时连接
        removeAbandoned: false
        # 超时时间 (以秒数为单位)
        remove-abandoned-timeout: 1800
        logAbandoned: true
        pinGlobalTxToPhysicalConnection: true
      mydbtwo:
        url: jdbc:mysql://localhost:3306/mydbtwo?useUnicode=true&characterEncoding=utf-8&useSSL=false&serverTimezone=GMT%2B8&pinGlobalTxToPhysicalConnection=true&autoReconnect=true
        username: root
        password: root
        driver-class-name: com.mysql.cj.jdbc.Driver
        initialSize: 6
        minIdle: 6
        maxActive: 10
        maxWait: 60000
        timeBetweenEvictionRunsMillis: 60000
        minEvictableIdleTimeMillis: 300000
        validationQuery: SELECT 1
        testWhileIdle: true
        testOnBorrow: false
        testOnReturn: false
        removeAbandoned: false
        remove-abandoned-timeout: 1800
        logAbandoned: true
        pinGlobalTxToPhysicalConnection: true
      # WebStatFilter 用于采集 web-jdbc 关联监控的数据。
      web-stat-filter:
        # 是否开启 WebStatFilter 默认是 true
        enabled: true
        # 需要拦截的 url
        url-pattern: /*
        # 排除静态资源的请求
        exclusions: "*.js,*.gif,*.jpg,*.png,*.css,*.ico,/druid/*"
      # Druid 内置提供了一个 StatViewServlet 用于展示 Druid 的统计信息。
      stat-view-servlet:
        #是否启用 StatViewServlet 默认值 true
        enabled: true
        # 需要拦截的 url
        url-pattern: /druid/*
        # 允许清空统计数据
        reset-enable: true
        login-username: myname
        login-password: mypwd

-----接下来就是代码环节-----

大家多注意看注释，很多关键信息都用注释方式进行了简明的介绍：

先创建一个自定义注解，DataSource.java：

import java.lang.annotation.*;
/**
 * @Author : JCccc
 * @CreateTime : 2019/8/28
 * @Description :
 **/
@Documented
@Target({ElementType.METHOD})
@Retention(RetentionPolicy.RUNTIME)
public @interface DataSource {
    String value() default DataSourceNames.ONE;
}

然后是创建 DataSourceNames.java，用于简单数据源命名：

/**
 * @Author : JCccc
 * @CreateTime : 2019/8/28
 * @Description :
 **/
public interface DataSourceNames {
    String ONE = "ONE";
    String TWO = "TWO";
}

ps：其实这些都是我之前aop切换数据源的时候敲的，大概8月份的时候，这次我相当于在这个基础上着重解决事务问题

然后是将自定义注解作为切点，进行aop方式动态切换逻辑补全，创建DynamicDataSourceAspect.java：

import com.test.jtadbsource.dbConfig.DataSourceContextHolder;
import org.aspectj.lang.JoinPoint;
import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.*;
import org.aspectj.lang.reflect.MethodSignature;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.stereotype.Component;
import java.lang.reflect.Method;
/**
 * @Author : JCccc
 * @CreateTime : 2019/12/10
 * @Description :
 **/
@Aspect
@Component
public class DynamicDataSourceAspect {
    protected Logger logger = LoggerFactory.getLogger(getClass());
    /**
     * 切点: 所有配置 DataSource 注解的方法
     */
    @Pointcut("@annotation(com.test.jtadbsource.dbAop.DataSource)")
    public void dataSourcePointCut() {}
    @Around("dataSourcePointCut()")
    public Object around(ProceedingJoinPoint point) throws Throwable {
        DataSource ds = null;
        MethodSignature signature = (MethodSignature) point.getSignature();
        Method method = signature.getMethod();
        //获取自定义注解
        ds = method.getAnnotation(DataSource.class);
        if (ds == null) {
            //如果监测到自定义注解不存在,那么默认切换到数据源 mydbone
            DataSourceContextHolder.setDataSourceKey(DataSourceNames.ONE);
            logger.info("set default datasource is " + DataSourceNames.ONE);
        } else {
            //自定义存在,则按照注解的值去切换数据源
            DataSourceContextHolder.setDataSourceKey(ds.value());
            logger.info("set datasource is " + ds.value());
        }
        return point.proceed();
    }
    @After(value = "dataSourcePointCut()")
    public void afterSwitchDS(JoinPoint point) {
        DataSourceContextHolder.clearDataSourceKey();
        logger.info("clean datasource");
    }
}

上面用到的DataSourceContextHolder.java：

import org.springframework.jdbc.datasource.lookup.AbstractRoutingDataSource;
/**
 * @Author : JCccc
 * @CreateTime : 2019/12/10
 * @Description :
 **/
public class DataSourceContextHolder extends AbstractRoutingDataSource {
    private static final ThreadLocal<String> contextHolder = new ThreadLocal<>();
    // 设置数据源名
    public static void setDataSourceKey(String dbName) {
        contextHolder.set(dbName);
    }
    // 获取数据源名
    public static String getDataSourceKey() {
        return contextHolder.get();
    }
    // 清除数据源名
    public static void clearDataSourceKey() {
        contextHolder.remove();
    }
    @Override
    protected Object determineCurrentLookupKey() {
        return getDataSourceKey();
    }
}

ok，到这里，基本的动态切换边框的东西都完毕了，接下来是比较核心的：

1. DataSourceFactory.java ：

用于不同的数据源DataSource的信息配置，使用DruidXADataSource创建，支持jta事务；

将不同数据源DataSource分别都关联上对应的AtomikosDataSourceBean，这样事务能提取到JTA事务管理器；

重写数据源会话工厂，为每个数据源单独配置一个。

配置重写的sqlSessionTemplate，将实际使用的不同数据源的sqlsession和spring的事务机制关联起来。

import com.alibaba.druid.pool.xa.DruidXADataSource;
import com.test.jtadbsource.dbAop.DataSourceNames;
import org.apache.ibatis.logging.stdout.StdOutImpl;
import org.apache.ibatis.session.SqlSessionFactory;
import org.mybatis.spring.SqlSessionFactoryBean;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.boot.jta.atomikos.AtomikosDataSourceBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.io.support.PathMatchingResourcePatternResolver;
import org.springframework.core.io.support.ResourcePatternResolver;
import javax.sql.DataSource;
import java.util.HashMap;
import java.util.Map;
/**
 * @Author : JCccc
 * @CreateTime : 2019/12/10
 * @Description :多数据源配置
 **/
@Configuration
@MapperScan(basePackages = DataSourceFactory.BASE_PACKAGES, sqlSessionTemplateRef = "sqlSessionTemplate")
public class DataSourceFactory {
    static final String BASE_PACKAGES = "com.test.jtadbsource.mapper";
    private static final String MAPPER_LOCATION = "classpath:mybatis/mapper/*.xml";
    /***
     * 创建 DruidXADataSource mydbone 用@ConfigurationProperties 自动配置属性
     */
    @Bean
    @ConfigurationProperties("spring.datasource.druid.mydbone")
    public DataSource druidDataSourceOne() {
        return new DruidXADataSource();
    }
    /***
     * 创建 DruidXADataSource mydbtwo
     */
    @Bean
    @ConfigurationProperties("spring.datasource.druid.mydbtwo")
    public DataSource druidDataSourceTwo() {
        return new DruidXADataSource();
    }
    /**
     * 创建支持 XA 事务的 Atomikos 数据源 mydbone
     */
    @Bean
    public DataSource dataSourceOne(DataSource druidDataSourceOne) {
        AtomikosDataSourceBean sourceBean = new AtomikosDataSourceBean();
        sourceBean.setXaDataSource((DruidXADataSource) druidDataSourceOne);
        // 必须为数据源指定唯一标识
        sourceBean.setPoolSize(5);
        sourceBean.setTestQuery("SELECT 1");
        sourceBean.setUniqueResourceName("mydbone");
        return sourceBean;
    }
    /**
     * 创建支持 XA 事务的 Atomikos 数据源 mydbtwo
     */
    @Bean
    public DataSource dataSourceTwo(DataSource druidDataSourceTwo) {
        AtomikosDataSourceBean sourceBean = new AtomikosDataSourceBean();
        sourceBean.setXaDataSource((DruidXADataSource) druidDataSourceTwo);
        sourceBean.setPoolSize(5);
        sourceBean.setTestQuery("SELECT 1");
        sourceBean.setUniqueResourceName("mydbtwo");
        return sourceBean;
    }
    /**
     * @param dataSourceOne 数据源 mydbone
     * @return 数据源 mydbone 的会话工厂
     */
    @Bean
    public SqlSessionFactory sqlSessionFactoryOne(DataSource dataSourceOne)
            throws Exception {
        return createSqlSessionFactory(dataSourceOne);
    }
    /**
     * @param dataSourceTwo 数据源 mydbtwo
     * @return 数据源 mydbtwo 的会话工厂
     */
    @Bean
    public SqlSessionFactory sqlSessionFactoryTwo(DataSource dataSourceTwo)
            throws Exception {
        return createSqlSessionFactory(dataSourceTwo);
    }
    /***
     * sqlSessionTemplate 与 Spring 事务管理一起使用，以确保使用的实际 SqlSession 是与当前 Spring 事务关联的,
     * 此外它还管理会话生命周期，包括根据 Spring 事务配置根据需要关闭，提交或回滚会话
     * @param sqlSessionFactoryOne 数据源 mydbone
     * @param sqlSessionFactoryTwo 数据源 mydbtwo
     */
    @Bean
    public CustomSqlSessionTemplate sqlSessionTemplate(SqlSessionFactory sqlSessionFactoryOne, SqlSessionFactory sqlSessionFactoryTwo) {
        Map<Object, SqlSessionFactory> sqlSessionFactoryMap = new HashMap<>();
        sqlSessionFactoryMap.put(DataSourceNames.ONE, sqlSessionFactoryOne);
        sqlSessionFactoryMap.put(DataSourceNames.TWO, sqlSessionFactoryTwo);
        CustomSqlSessionTemplate customSqlSessionTemplate = new CustomSqlSessionTemplate(sqlSessionFactoryOne);
        customSqlSessionTemplate.setTargetSqlSessionFactories(sqlSessionFactoryMap);
        return customSqlSessionTemplate;
    }
    /***
     * 自定义会话工厂
     * @param dataSource 数据源
     * @return :自定义的会话工厂
     */
    private SqlSessionFactory createSqlSessionFactory(DataSource dataSource) throws Exception {
        SqlSessionFactoryBean factoryBean = new SqlSessionFactoryBean();
        factoryBean.setDataSource(dataSource);
        org.apache.ibatis.session.Configuration configuration = new org.apache.ibatis.session.Configuration();
        //配置驼峰命名
        configuration.setMapUnderscoreToCamelCase(true);
        //配置sql日志
        configuration.setLogImpl(StdOutImpl.class);
        factoryBean.setConfiguration(configuration);
        ResourcePatternResolver resolver = new PathMatchingResourcePatternResolver();
        //配置读取mapper.xml路径
        factoryBean.setMapperLocations(resolver.getResources(MAPPER_LOCATION));
        return factoryBean.getObject();
    }
}

上面用到的自定义CustomSqlSessionTemplate （重写SqlSessionTemplate）：

import static java.lang.reflect.Proxy.newProxyInstance;
import static org.apache.ibatis.reflection.ExceptionUtil.unwrapThrowable;
import static org.mybatis.spring.SqlSessionUtils.closeSqlSession;
import static org.mybatis.spring.SqlSessionUtils.getSqlSession;
import static org.mybatis.spring.SqlSessionUtils.isSqlSessionTransactional;
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.sql.Connection;
import java.util.List;
import java.util.Map;
import org.apache.ibatis.exceptions.PersistenceException;
import org.apache.ibatis.executor.BatchResult;
import org.apache.ibatis.session.Configuration;
import org.apache.ibatis.session.ExecutorType;
import org.apache.ibatis.session.ResultHandler;
import org.apache.ibatis.session.RowBounds;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.mybatis.spring.MyBatisExceptionTranslator;
import org.mybatis.spring.SqlSessionTemplate;
import org.springframework.dao.support.PersistenceExceptionTranslator;
import org.springframework.util.Assert;
public class CustomSqlSessionTemplate extends SqlSessionTemplate {
    private final SqlSessionFactory sqlSessionFactory;
    private final ExecutorType executorType;
    private final SqlSession sqlSessionProxy;
    private final PersistenceExceptionTranslator exceptionTranslator;
    private Map<Object, SqlSessionFactory> targetSqlSessionFactories;
    private SqlSessionFactory defaultTargetSqlSessionFactory;
    /**
     * 通过Map传入
     * @param targetSqlSessionFactories
     */
    public void setTargetSqlSessionFactories(Map<Object, SqlSessionFactory> targetSqlSessionFactories) {
        this.targetSqlSessionFactories = targetSqlSessionFactories;
    }
    public void setDefaultTargetSqlSessionFactory(SqlSessionFactory defaultTargetSqlSessionFactory) {
        this.defaultTargetSqlSessionFactory = defaultTargetSqlSessionFactory;
    }
    public CustomSqlSessionTemplate(SqlSessionFactory sqlSessionFactory) {
        this(sqlSessionFactory, sqlSessionFactory.getConfiguration().getDefaultExecutorType());
    }
    public CustomSqlSessionTemplate(SqlSessionFactory sqlSessionFactory, ExecutorType executorType) {
        this(sqlSessionFactory, executorType, new MyBatisExceptionTranslator(sqlSessionFactory.getConfiguration()
                .getEnvironment().getDataSource(), true));
    }
    public CustomSqlSessionTemplate(SqlSessionFactory sqlSessionFactory, ExecutorType executorType,
                                    PersistenceExceptionTranslator exceptionTranslator) {
        super(sqlSessionFactory, executorType, exceptionTranslator);
        this.sqlSessionFactory = sqlSessionFactory;
        this.executorType = executorType;
        this.exceptionTranslator = exceptionTranslator;
        this.sqlSessionProxy = (SqlSession) newProxyInstance(
                SqlSessionFactory.class.getClassLoader(),
                new Class[] { SqlSession.class },
                new SqlSessionInterceptor());
        this.defaultTargetSqlSessionFactory = sqlSessionFactory;
    }
    //通过DataSourceContextHolder获取当前的会话工厂
    @Override
    public SqlSessionFactory getSqlSessionFactory() {
        String dataSourceKey = DataSourceContextHolder.getDataSourceKey();
        SqlSessionFactory targetSqlSessionFactory = targetSqlSessionFactories.get(dataSourceKey);
        if (targetSqlSessionFactory != null) {
            return targetSqlSessionFactory;
        } else if (defaultTargetSqlSessionFactory != null) {
            return defaultTargetSqlSessionFactory;
        } else {
            Assert.notNull(targetSqlSessionFactories, "Property 'targetSqlSessionFactories' or 'defaultTargetSqlSessionFactory' are required");
            Assert.notNull(defaultTargetSqlSessionFactory, "Property 'defaultTargetSqlSessionFactory' or 'targetSqlSessionFactories' are required");
        }
        return this.sqlSessionFactory;
    }
    @Override
    public Configuration getConfiguration() {
        return this.getSqlSessionFactory().getConfiguration();
    }
    public ExecutorType getExecutorType() {
        return this.executorType;
    }
    public PersistenceExceptionTranslator getPersistenceExceptionTranslator() {
        return this.exceptionTranslator;
    }
    /**
     * {@inheritDoc}
     */
    public <T> T selectOne(String statement) {
        return this.sqlSessionProxy.<T> selectOne(statement);
    }
    /**
     * {@inheritDoc}
     */
    public <T> T selectOne(String statement, Object parameter) {
        return this.sqlSessionProxy.<T> selectOne(statement, parameter);
    }
    /**
     * {@inheritDoc}
     */
    public <K, V> Map<K, V> selectMap(String statement, String mapKey) {
        return this.sqlSessionProxy.<K, V> selectMap(statement, mapKey);
    }
    /**
     * {@inheritDoc}
     */
    public <K, V> Map<K, V> selectMap(String statement, Object parameter, String mapKey) {
        return this.sqlSessionProxy.<K, V> selectMap(statement, parameter, mapKey);
    }
    /**
     * {@inheritDoc}
     */
    public <K, V> Map<K, V> selectMap(String statement, Object parameter, String mapKey, RowBounds rowBounds) {
        return this.sqlSessionProxy.<K, V> selectMap(statement, parameter, mapKey, rowBounds);
    }
    /**
     * {@inheritDoc}
     */
    public <E> List<E> selectList(String statement) {
        return this.sqlSessionProxy.<E> selectList(statement);
    }
    /**
     * {@inheritDoc}
     */
    public <E> List<E> selectList(String statement, Object parameter) {
        return this.sqlSessionProxy.<E> selectList(statement, parameter);
    }
    /**
     * {@inheritDoc}
     */
    public <E> List<E> selectList(String statement, Object parameter, RowBounds rowBounds) {
        return this.sqlSessionProxy.<E> selectList(statement, parameter, rowBounds);
    }
    /**
     * {@inheritDoc}
     */
    public void select(String statement, ResultHandler handler) {
        this.sqlSessionProxy.select(statement, handler);
    }
    /**
     * {@inheritDoc}
     */
    public void select(String statement, Object parameter, ResultHandler handler) {
        this.sqlSessionProxy.select(statement, parameter, handler);
    }
    /**
     * {@inheritDoc}
     */
    public void select(String statement, Object parameter, RowBounds rowBounds, ResultHandler handler) {
        this.sqlSessionProxy.select(statement, parameter, rowBounds, handler);
    }
    /**
     * {@inheritDoc}
     */
    public int insert(String statement) {
        return this.sqlSessionProxy.insert(statement);
    }
    /**
     * {@inheritDoc}
     */
    public int insert(String statement, Object parameter) {
        return this.sqlSessionProxy.insert(statement, parameter);
    }
    /**
     * {@inheritDoc}
     */
    public int update(String statement) {
        return this.sqlSessionProxy.update(statement);
    }
    /**
     * {@inheritDoc}
     */
    public int update(String statement, Object parameter) {
        return this.sqlSessionProxy.update(statement, parameter);
    }
    /**
     * {@inheritDoc}
     */
    public int delete(String statement) {
        return this.sqlSessionProxy.delete(statement);
    }
    /**
     * {@inheritDoc}
     */
    public int delete(String statement, Object parameter) {
        return this.sqlSessionProxy.delete(statement, parameter);
    }
    /**
     * {@inheritDoc}
     */
    public <T> T getMapper(Class<T> type) {
        return getConfiguration().getMapper(type, this);
    }
    /**
     * {@inheritDoc}
     */
    public void commit() {
        throw new UnsupportedOperationException("Manual commit is not allowed over a Spring managed SqlSession");
    }
    /**
     * {@inheritDoc}
     */
    public void commit(boolean force) {
        throw new UnsupportedOperationException("Manual commit is not allowed over a Spring managed SqlSession");
    }
    /**
     * {@inheritDoc}
     */
    public void rollback() {
        throw new UnsupportedOperationException("Manual rollback is not allowed over a Spring managed SqlSession");
    }
    /**
     * {@inheritDoc}
     */
    public void rollback(boolean force) {
        throw new UnsupportedOperationException("Manual rollback is not allowed over a Spring managed SqlSession");
    }
    /**
     * {@inheritDoc}
     */
    public void close() {
        throw new UnsupportedOperationException("Manual close is not allowed over a Spring managed SqlSession");
    }
    /**
     * {@inheritDoc}
     */
    public void clearCache() {
        this.sqlSessionProxy.clearCache();
    }
    /**
     * {@inheritDoc}
     */
    public Connection getConnection() {
        return this.sqlSessionProxy.getConnection();
    }
    /**
     * {@inheritDoc}
     * @since 1.0.2
     */
    public List<BatchResult> flushStatements() {
        return this.sqlSessionProxy.flushStatements();
    }
    /**
     * Proxy needed to route MyBatis method calls to the proper SqlSession got from Spring's Transaction Manager It also
     * unwraps exceptions thrown by {@code Method#invoke(Object, Object...)} to pass a {@code PersistenceException} to
     * the {@code PersistenceExceptionTranslator}.
     */
    private class SqlSessionInterceptor implements InvocationHandler {
        public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
            final SqlSession sqlSession = getSqlSession(
                    CustomSqlSessionTemplate.this.getSqlSessionFactory(),
                    CustomSqlSessionTemplate.this.executorType,
                    CustomSqlSessionTemplate.this.exceptionTranslator);
            try {
                Object result = method.invoke(sqlSession, args);
                if (!isSqlSessionTransactional(sqlSession, CustomSqlSessionTemplate.this.getSqlSessionFactory())) {
                    sqlSession.commit(true);
                }
                return result;
            } catch (Throwable t) {
                Throwable unwrapped = unwrapThrowable(t);
                if (CustomSqlSessionTemplate.this.exceptionTranslator != null && unwrapped instanceof PersistenceException) {
                    Throwable translated = CustomSqlSessionTemplate.this.exceptionTranslator
                            .translateExceptionIfPossible((PersistenceException) unwrapped);
                    if (translated != null) {
                        unwrapped = translated;
                    }
                }
                throw unwrapped;
            } finally {
                closeSqlSession(sqlSession, CustomSqlSessionTemplate.this.getSqlSessionFactory());
            }
        }
    }
}

然后是xat分布式事务管理器，XATransactionManagerConfig.java：

import com.atomikos.icatch.jta.UserTransactionImp;
import com.atomikos.icatch.jta.UserTransactionManager;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.transaction.PlatformTransactionManager;
import org.springframework.transaction.annotation.EnableTransactionManagement;
import org.springframework.transaction.jta.JtaTransactionManager;
import javax.transaction.TransactionManager;
import javax.transaction.UserTransaction;
/**
 * @Author : JCccc
 * @CreateTime : 2019/12/10
 * @Description :JTA 事务配置
 **/
@Configuration
@EnableTransactionManagement
public class XATransactionManagerConfig {
    @Bean
    public UserTransaction userTransaction() throws Throwable {
        UserTransactionImp userTransactionImp = new UserTransactionImp();
        userTransactionImp.setTransactionTimeout(10000);
        return userTransactionImp;
    }
    @Bean
    public TransactionManager atomikosTransactionManager() {
        UserTransactionManager userTransactionManager = new UserTransactionManager();
        userTransactionManager.setForceShutdown(true);
        return userTransactionManager;
    }
    @Bean
    public PlatformTransactionManager transactionManager(UserTransaction userTransaction,
                                                         TransactionManager transactionManager) {
        return new JtaTransactionManager(userTransaction, transactionManager);
    }
}

然后，在启动类上，去除掉自动加载的数据源配置类，

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.autoconfigure.jdbc.DataSourceAutoConfiguration;
@SpringBootApplication(exclude = {DataSourceAutoConfiguration.class})
public class JtadbsourceApplication {
    public static void main(String[] args) {
        SpringApplication.run(JtadbsourceApplication.class, args);
    }
}

到这里，aop注解方式整合多数据源+分布式事务jta已经完毕了！

接下来就是使用测试环节，包括单数据源数据插入&事务回滚，多数据源切换插入&事务回滚：

首先创建实体类，User.java：

import lombok.Data;
import lombok.ToString;
/**
 * @Author : JCccc
 * @CreateTime : 2019/10/22
 * @Description :
 **/
@Data
@ToString
public class User {
    private Integer id;
    private String username;
    private Integer age;
}

然后是UserMapper.java：

import com.test.jtadbsource.pojo.User;
import org.apache.ibatis.annotations.Mapper;
import org.springframework.stereotype.Repository;
/**
 * @Author : JCccc
 * @CreateTime : 2019/12/10
 * @Description :
 **/
@Mapper
public interface UserMapper {
     int insert(User user);
}

然后是创建一个TestJtaservice.java：

import com.test.jtadbsource.pojo.User;
/**
 * @Author : JCccc
 * @CreateTime : 2019/12/9
 * @Description :
 **/
public interface TestJtaService {
    void testInsertUser(User user);
    void testInsertUser2(User user);
}

然后是TestJtaServiceImpl.java ，这里将会通过我们开始创建的自定义注解来标识，哪些service使用哪些数据源：

import com.test.jtadbsource.dbAop.DataSource;
import com.test.jtadbsource.dbAop.DataSourceNames;
import com.test.jtadbsource.mapper.UserMapper;
import com.test.jtadbsource.pojo.User;
import com.test.jtadbsource.service.TestJtaService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
/**
 * @Author : JCccc
 * @CreateTime : 2019/12/9
 * @Description :
 **/
@Service
public class TestJtaServiceImpl implements TestJtaService {
    @Autowired
    UserMapper userMapper;
    public void testInsertUser(User user){
        int insertNum = userMapper.insert(user);
        System.out.println("插入成功,条数："+insertNum);
    }
    @DataSource(DataSourceNames.TWO)
    public void testInsertUser2(User user){
        int insertNum = userMapper.insert(user);
        System.out.println("插入成功,条数："+insertNum);
    }
}