• Spring框架-经典的案例和demo,一些可以直接用于生产,使用atomikos来处理多数据源的一致性事务等


    Spring Examples

    Demo website:http://www.ityouknow.com/

    对Spring框架的学习,包括一些经典的案例和demo,一些可以直接用于生产。

    atomikos官网:https://www.atomikos.com/Documentation/SpringIntegration

    spring 多数据源配置

    spring 多数据源配置一般有两种方案:

    1、在spring项目启动的时候直接配置两个不同的数据源,不同的sessionFactory。在dao 层根据不同业务自行选择使用哪个数据源的session来操作。

    2、配置多个不同的数据源,使用一个sessionFactory,在业务逻辑使用的时候自动切换到不同的数据源,有一个种是在拦截器里面根据不同的业务现切换到不同的datasource;有的会在业务层根据业务来自动切换。但这种方案在多线程并发的时候会出现一些问题,需要使用threadlocal等技术来实现多线程竞争切换数据源的问题。

    【本文暂时只讨论第一种方案】

    spring多事务配置主要体现在db配置这块,配置不同的数据源和不同的session

    1、一下贴出 spring-db.xml配置

    复制代码
    <?xml version="1.0" encoding="UTF-8"?>
    <beans xmlns="http://www.springframework.org/schema/beans"
        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xmlns:context="http://www.springframework.org/schema/context"
        xmlns:aop="http://www.springframework.org/schema/aop" 
        xmlns:tx="http://www.springframework.org/schema/tx"
        xsi:schemaLocation="
        http://www.springframework.org/schema/beans 
        http://www.springframework.org/schema/beans/spring-beans-3.0.xsd 
        http://www.springframework.org/schema/context 
        http://www.springframework.org/schema/context/spring-context-3.0.xsd
        http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-3.1.xsd 
        http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.1.xsd">
    
        <bean id="test1DataSource" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close" >
            <property name="driverClassName" value="${database.test1.driverClassName}" />
            <property name="url" value="${database.test1.url}" />
            <property name="username" value="${database.test1.username}" />
            <property name="password" value="${database.test1.password}" />
        </bean>
        
        <bean id="test2DataSource" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close" >
            <property name="driverClassName" value="${database.test2.driverClassName}" />
            <property name="url" value="${database.test2.url}" />
            <property name="username" value="${database.test2.username}" />
            <property name="password" value="${database.test2.password}" />
        </bean>
        
        <bean id="test1SqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">  
            <property name="dataSource" ref="test1DataSource" />
            <property name="configLocation" value="classpath:mybatis/mybatis-config.xml"></property>
            <property name="mapperLocations" value="classpath*:mybatis/mapper/*.xml" />
        </bean>  
        
        <bean id="test2SqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">  
            <property name="dataSource" ref="test2DataSource" />
            <property name="configLocation" value="classpath:mybatis/mybatis-config.xml"></property>
            <property name="mapperLocations" value="classpath*:mybatis/mapper/*.xml" />
        </bean>  
        
        <bean id="test1TxManager"   class="org.springframework.jdbc.datasource.DataSourceTransactionManager">  
            <property name="dataSource" ref="test1DataSource"></property>  
        </bean>  
        <bean id="test2TxManager"   class="org.springframework.jdbc.datasource.DataSourceTransactionManager">  
            <property name="dataSource" ref="test2DataSource"></property>  
        </bean>  
      
        <tx:annotation-driven transaction-manager="test2TxManager" />
        <tx:annotation-driven transaction-manager="test1TxManager" />
        
    </beans>
    复制代码

    2、dao层做了一个小的封装,将不同的SqlSessionFactory 注入到 SessionFactory,通过BaseDao来做简单的封装,封装不同库的基本增删改。dao实现层都集成于Basedao 这样的话,实现可以根据自己需要来选择不同的库来操作不同的内容。

    session工厂

    复制代码
    package com.neo.dao;
    
    import com.neo.entity.Entity;
    
    public class BaseDao extends SessionFactory{
        
        
        public void test1Update(Entity entity) {
        this.getTest1Session().update(entity.getClass().getSimpleName()+".update", entity);
        }
        
        public void test2Update(Entity entity) {
           this.getTest2Session().update(entity.getClass().getSimpleName()+".update", entity);
           }
    }
    复制代码

    BaseDao

    复制代码
    package com.neo.dao;
    
    import com.neo.entity.Entity;
    
    public class BaseDao extends SessionFactory{
        
        
        public void test1Update(Entity entity) {
        this.getTest1Session().update(entity.getClass().getSimpleName()+".update", entity);
        }
        
        public void test2Update(Entity entity) {
           this.getTest2Session().update(entity.getClass().getSimpleName()+".update", entity);
           }
    }
    复制代码

    以上的配置在多数据源连接,正常的增删改都是没有问题的,但是遇到分布式的事务是就出问题:

    测试代码:

    复制代码
    package com.neo.service.impl;
    
    import javax.annotation.Resource;
    
    import org.springframework.stereotype.Service;
    import org.springframework.transaction.annotation.Transactional;
    
    import com.neo.dao.UserDao;
    import com.neo.dao.UserInformationsDao;
    import com.neo.entity.UserEntity;
    import com.neo.entity.UserInformationsEntity;
    import com.neo.service.UserService;
    
    @Service
    public class UserServiceImpl implements UserService {
        
        @Resource UserDao userDao;
        @Resource UserInformationsDao userInformationsDao;
    
        @Override
        @Transactional
        public void updateUserinfo() {
        
        UserEntity user=new UserEntity();
        user.setId(1);
        user.setUserName("李四4");
        
        UserInformationsEntity userInfo=new UserInformationsEntity();
        userInfo.setUserId(1);
        userInfo.setAddress("陕西4");
        
        userDao.updateUser(user);
        userInformationsDao.updateUserInformations(userInfo);
        
        if(true){
            throw new RuntimeException("test tx ");
        }
        }
        
        
    
    }
    复制代码

    在service添加事务后,更新完毕抛出异常,test2更新进行了回滚,test1 数据更新没有回滚。

    解决方案添加分布式的事务,Atomikos和spring结合来处理。

    Atomikos多数据源的配置

    复制代码
    <?xml version="1.0" encoding="UTF-8"?>
    <beans xmlns="http://www.springframework.org/schema/beans"
        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xmlns:context="http://www.springframework.org/schema/context"
        xmlns:aop="http://www.springframework.org/schema/aop" 
        xmlns:tx="http://www.springframework.org/schema/tx"
        xsi:schemaLocation="
        http://www.springframework.org/schema/beans 
        http://www.springframework.org/schema/beans/spring-beans-3.0.xsd 
        http://www.springframework.org/schema/context 
        http://www.springframework.org/schema/context/spring-context-3.0.xsd
        http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-3.1.xsd 
        http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.1.xsd">
    
         <bean id="test1DataSource" class="com.atomikos.jdbc.AtomikosDataSourceBean" init-method="init" destroy-method="close">
            <property name="uniqueResourceName" value="test1"/>
            <property name="xaDataSourceClassName" value="com.mysql.jdbc.jdbc2.optional.MysqlXADataSource"/>
            <property name="xaProperties">
                <props>
                    <prop key="url">${database.test1.url}</prop>
                    <prop key="user">${database.test1.username}</prop>
                    <prop key="password">${database.test1.password}</prop>
                </props>
            </property>
            <property name="minPoolSize" value="10" />
            <property name="maxPoolSize" value="100" />
            <property name="borrowConnectionTimeout" value="30" />
            <property name="testQuery" value="select 1" />
            <property name="maintenanceInterval" value="60" />
        </bean>
        
         <bean id="test2DataSource" class="com.atomikos.jdbc.AtomikosDataSourceBean" init-method="init" destroy-method="close">
            <property name="uniqueResourceName" value="test2"/>
            <property name="xaDataSourceClassName" value="com.mysql.jdbc.jdbc2.optional.MysqlXADataSource"/>
            <property name="xaProperties">
                <props>
                    <prop key="url">${database.test2.url}</prop>
                    <prop key="user">${database.test2.username}</prop>
                    <prop key="password">${database.test2.password}</prop>
                </props>
            </property>
            <property name="minPoolSize" value="10" />
            <property name="maxPoolSize" value="100" />
            <property name="borrowConnectionTimeout" value="30" />
            <property name="testQuery" value="select 1" />
            <property name="maintenanceInterval" value="60" />
        </bean>
        
        <bean id="test1SqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">  
            <property name="dataSource" ref="test1DataSource" />
            <property name="configLocation" value="classpath:mybatis/mybatis-config.xml"></property>
            <property name="mapperLocations" value="classpath*:mybatis/mapper/*.xml" />
        </bean>  
        
        <bean id="test2SqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">  
            <property name="dataSource" ref="test2DataSource" />
            <property name="configLocation" value="classpath:mybatis/mybatis-config.xml"></property>
            <property name="mapperLocations" value="classpath*:mybatis/mapper/*.xml" />
        </bean>  
        
        <!-- 分布式事务 -->
        <bean id="atomikosTransactionManager" class="com.atomikos.icatch.jta.UserTransactionManager" init-method="init" destroy-method="close">
            <property name="forceShutdown" value="true"/>
        </bean>
        
        <bean id="atomikosUserTransaction" class="com.atomikos.icatch.jta.UserTransactionImp">
            <property name="transactionTimeout" value="300"/>
        </bean>
        
        <bean id="transactionManager" class="org.springframework.transaction.jta.JtaTransactionManager">
            <property name="transactionManager" ref="atomikosTransactionManager"/>
            <property name="userTransaction" ref="atomikosUserTransaction"/>
        </bean>
        
        <tx:annotation-driven/>
        
    </beans>
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  • 原文地址:https://www.cnblogs.com/guoziyi/p/10100996.html
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