首先，到底啥是分散式事務呢，例如我們在執行一個業務邏輯的時候有兩步分別操作A資料來源和B資料來源，當我們在A資料來源執行數據更改後，在B資料來源執行時出現運行時異常，那麼我們必須要讓B資料來源的操作回滾，並回滾對A資料來源的操作；這種情況在支付業務時常常出現；例如買票業務在最後支付失敗，那之前的操作必須全部回滾，如果先前的操作分佈在多個資料來源中，那麼這就是典型的分散式事務回滾；
了解了什麼是分散式事務，那分散式事務在java的解決方案就是JTA(即Java Transaction API)；springboot官方提供了Atomikos or Bitronix的解決思路；
其實，大多數情況下很多公司是使用訊息隊列的方式實作分散式事務。
本篇文章重點講解springboot環境下，整合Atomikos mysql mybatis tomcat/jetty;
#pom. xml中加入atomikos的springboot相關依賴：
<!--分布式事务--> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-jta-atomikos</artifactId> </dependency>
點進去會發現裡面整合好了：transactions-jms、transactions-jta、transactions-jdbc、javax.transaction-api
將資料來源的相關設定項單獨提煉到一個application.yml中：
注意：
#這回我們的spring.datasource.type 是com.alibaba.druid.pool.xa.DruidXADataSource;
spring.jta.transaction-manager-id的值在你的電腦中是唯一的，這個詳細請閱讀官方文件；
#完整的yml檔案如下：
spring: datasource: type: com.alibaba.druid.pool.xa.DruidXADataSource druid: systemDB: name: systemDB url: jdbc:mysql://localhost:3306/springboot-mybatis?useUnicode=true&characterEncoding=utf-8 username: root password: root # 下面为连接池的补充设置，应用到上面所有数据源中 # 初始化大小，最小，最大 initialSize: 5 minIdle: 5 maxActive: 20 # 配置获取连接等待超时的时间 maxWait: 60000 # 配置间隔多久才进行一次检测，检测需要关闭的空闲连接，单位是毫秒 timeBetweenEvictionRunsMillis: 60000 # 配置一个连接在池中最小生存的时间，单位是毫秒 minEvictableIdleTimeMillis: 30 validationQuery: SELECT 1 validationQueryTimeout: 10000 testWhileIdle: true testOnBorrow: false testOnReturn: false # 打开PSCache，并且指定每个连接上PSCache的大小 poolPreparedStatements: true maxPoolPreparedStatementPerConnectionSize: 20 filters: stat,wall # 通过connectProperties属性来打开mergeSql功能；慢SQL记录 connectionProperties: druid.stat.mergeSql=true;druid.stat.slowSqlMillis=5000 # 合并多个DruidDataSource的监控数据 useGlobalDataSourceStat: true businessDB: name: businessDB url: jdbc:mysql://localhost:3306/springboot-mybatis2?useUnicode=true&characterEncoding=utf-8 username: root password: root # 下面为连接池的补充设置，应用到上面所有数据源中 # 初始化大小，最小，最大 initialSize: 5 minIdle: 5 maxActive: 20 # 配置获取连接等待超时的时间 maxWait: 60000 # 配置间隔多久才进行一次检测，检测需要关闭的空闲连接，单位是毫秒 timeBetweenEvictionRunsMillis: 60000 # 配置一个连接在池中最小生存的时间，单位是毫秒 minEvictableIdleTimeMillis: 30 validationQuery: SELECT 1 validationQueryTimeout: 10000 testWhileIdle: true testOnBorrow: false testOnReturn: false # 打开PSCache，并且指定每个连接上PSCache的大小 poolPreparedStatements: true maxPoolPreparedStatementPerConnectionSize: 20 filters: stat,wall # 通过connectProperties属性来打开mergeSql功能；慢SQL记录 connectionProperties: druid.stat.mergeSql=true;druid.stat.slowSqlMillis=5000 # 合并多个DruidDataSource的监控数据 useGlobalDataSourceStat: true #jta相关参数配置 jta: log-dir: classpath:tx-logs transaction-manager-id: txManager
在DruidConfig.java中實現多個資料來源的註冊；分散式事務管理器的註冊；druid的註冊
package com.zjt.config;
import com.alibaba.druid.filter.stat.StatFilter;
import com.alibaba.druid.support.http.StatViewServlet;
import com.alibaba.druid.support.http.WebStatFilter;
import com.alibaba.druid.wall.WallConfig;
import com.alibaba.druid.wall.WallFilter;
import com.atomikos.icatch.jta.UserTransactionImp;
import com.atomikos.icatch.jta.UserTransactionManager;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.jta.atomikos.AtomikosDataSourceBean;
import org.springframework.boot.web.servlet.FilterRegistrationBean;
import org.springframework.boot.web.servlet.ServletRegistrationBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Primary;
import org.springframework.core.env.Environment;
import org.springframework.transaction.jta.JtaTransactionManager;
import javax.sql.DataSource;
import javax.transaction.UserTransaction;
import java.util.Properties;
/**
* Druid配置
*
*
*/
@Configuration
public class DruidConfig {
@Bean(name = "systemDataSource")
@Primary
@Autowired
public DataSource systemDataSource(Environment env){
AtomikosDataSourceBean ds = new AtomikosDataSourceBean();
Properties prop = build(env, "spring.datasource.druid.systemDB.");
ds.setXaDataSourceClassName("com.alibaba.druid.pool.xa.DruidXADataSource");
ds.setUniqueResourceName("systemDB");
ds.setPoolSize(5);
ds.setXaProperties(prop);
return ds;
}
@Autowired
@Bean(name = "businessDataSource")
public AtomikosDataSourceBean businessDataSource(Environment env){
AtomikosDataSourceBean ds = new AtomikosDataSourceBean();
Properties prop = build(env, "spring.datasource.druid.businessDB.");
ds.setXaDataSourceClassName("com.alibaba.druid.pool.xa.DruidXADataSource");
ds.setUniqueResourceName("businessDB");
ds.setPoolSize(5);
ds.setXaProperties(prop);
return ds;
}
/**
* 注入事物管理器
* @return
*/
@Bean(name = "xatx")
public JtaTransactionManager regTransactionManager (){
UserTransactionManager userTransactionManager = new UserTransactionManager();
UserTransaction userTransaction = new UserTransactionImp();
return new JtaTransactionManager(userTransaction, userTransactionManager);
}
private Properties build(Environment env, String prefix){
Properties prop = new Properties();
prop.put("url", env.getProperty(prefix + "url"));
prop.put("username", env.getProperty(prefix + "username"));
prop.put("password", env.getProperty(prefix + "password"));
prop.put("driverClassName", env.getProperty(prefix + "driverClassName", ""));
prop.put("initialSize", env.getProperty(prefix + "initialSize", Integer.class));
prop.put("maxActive", env.getProperty(prefix + "maxActive", Integer.class));
prop.put("minIdle", env.getProperty(prefix + "minIdle", Integer.class));
prop.put("maxWait", env.getProperty(prefix + "maxWait", Integer.class));
prop.put("poolPreparedStatements", env.getProperty(prefix + "poolPreparedStatements", Boolean.class));
prop.put("maxPoolPreparedStatementPerConnectionSize",
env.getProperty(prefix + "maxPoolPreparedStatementPerConnectionSize", Integer.class));
prop.put("maxPoolPreparedStatementPerConnectionSize",
env.getProperty(prefix + "maxPoolPreparedStatementPerConnectionSize", Integer.class));
prop.put("validationQuery", env.getProperty(prefix + "validationQuery"));
prop.put("validationQueryTimeout", env.getProperty(prefix + "validationQueryTimeout", Integer.class));
prop.put("testOnBorrow", env.getProperty(prefix + "testOnBorrow", Boolean.class));
prop.put("testOnReturn", env.getProperty(prefix + "testOnReturn", Boolean.class));
prop.put("testWhileIdle", env.getProperty(prefix + "testWhileIdle", Boolean.class));
prop.put("timeBetweenEvictionRunsMillis",
env.getProperty(prefix + "timeBetweenEvictionRunsMillis", Integer.class));
prop.put("minEvictableIdleTimeMillis", env.getProperty(prefix + "minEvictableIdleTimeMillis", Integer.class));
prop.put("filters", env.getProperty(prefix + "filters"));
return prop;
}
@Bean
public ServletRegistrationBean druidServlet(){
ServletRegistrationBean servletRegistrationBean = new ServletRegistrationBean(new StatViewServlet(), "/druid/*");
//控制台管理用户，加入下面2行 进入druid后台就需要登录
//servletRegistrationBean.addInitParameter("loginUsername", "admin");
//servletRegistrationBean.addInitParameter("loginPassword", "admin");
return servletRegistrationBean;
}
@Bean
public FilterRegistrationBean filterRegistrationBean(){
FilterRegistrationBean filterRegistrationBean = new FilterRegistrationBean();
filterRegistrationBean.setFilter(new WebStatFilter());
filterRegistrationBean.addUrlPatterns("/*");
filterRegistrationBean.addInitParameter("exclusions", "*.js,*.gif,*.jpg,*.png,*.css,*.ico,/druid/*");
filterRegistrationBean.addInitParameter("profileEnable", "true");
return filterRegistrationBean;
}
@Bean
public StatFilter statFilter(){
StatFilter statFilter = new StatFilter();
statFilter.setLogSlowSql(true); //slowSqlMillis用来配置SQL慢的标准，执行时间超过slowSqlMillis的就是慢。
statFilter.setMergeSql(true); //SQL合并配置
statFilter.setSlowSqlMillis(1000);//slowSqlMillis的缺省值为3000，也就是3秒。
return statFilter;
}
@Bean
public WallFilter wallFilter(){
WallFilter wallFilter = new WallFilter();
//允许执行多条SQL
WallConfig config = new WallConfig();
config.setMultiStatementAllow(true);
wallFilter.setConfig(config);
return wallFilter;
}
}分別配置每個資料來源對應的sqlSessionFactory，以及MapperScan掃描的套件
##MybatisDatasourceConfig.java#
package com.zjt.config;
import com.zjt.util.MyMapper;
import org.apache.ibatis.session.SqlSessionFactory;
import org.mybatis.spring.SqlSessionFactoryBean;
import org.mybatis.spring.SqlSessionTemplate;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
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;
/**
*
* @description
*/
@Configuration
// 精确到 mapper 目录，以便跟其他数据源隔离
@MapperScan(basePackages = "com.zjt.mapper", markerInterface = MyMapper.class, sqlSessionFactoryRef = "sqlSessionFactory")
public class MybatisDatasourceConfig {
@Autowired
@Qualifier("systemDataSource")
private DataSource ds;
@Bean
public SqlSessionFactory sqlSessionFactory() throws Exception {
SqlSessionFactoryBean factoryBean = new SqlSessionFactoryBean();
factoryBean.setDataSource(ds);
//指定mapper xml目录
ResourcePatternResolver resolver = new PathMatchingResourcePatternResolver();
factoryBean.setMapperLocations(resolver.getResources("classpath:mapper/*.xml"));
return factoryBean.getObject();
}
@Bean
public SqlSessionTemplate sqlSessionTemplate() throws Exception {
SqlSessionTemplate template = new SqlSessionTemplate(sqlSessionFactory()); // 使用上面配置的Factory
return template;
}
//关于事务管理器，不管是JPA还是JDBC等都实现自接口 PlatformTransactionManager
// 如果你添加的是 spring-boot-starter-jdbc 依赖，框架会默认注入 DataSourceTransactionManager 实例。
//在Spring容器中，我们手工注解@Bean 将被优先加载，框架不会重新实例化其他的 PlatformTransactionManager 实现类。
/*@Bean(name = "transactionManager")
@Primary
public DataSourceTransactionManager masterTransactionManager() {
//MyBatis自动参与到spring事务管理中，无需额外配置，只要org.mybatis.spring.SqlSessionFactoryBean引用的数据源
// 与DataSourceTransactionManager引用的数据源一致即可，否则事务管理会不起作用。
return new DataSourceTransactionManager(ds);
}*/
}MybatisDatasource2Config.java
package com.zjt.config;
import com.zjt.util.MyMapper;
import org.apache.ibatis.session.SqlSessionFactory;
import org.mybatis.spring.SqlSessionFactoryBean;
import org.mybatis.spring.SqlSessionTemplate;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
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;
/**
*
* @description
*/
@Configuration
// 精确到 mapper 目录，以便跟其他数据源隔离
@MapperScan(basePackages = "com.zjt.mapper2", markerInterface = MyMapper.class, sqlSessionFactoryRef = "sqlSessionFactory2")
public class MybatisDatasource2Config {
@Autowired
@Qualifier("businessDataSource")
private DataSource ds;
@Bean
public SqlSessionFactory sqlSessionFactory2() throws Exception {
SqlSessionFactoryBean factoryBean = new SqlSessionFactoryBean();
factoryBean.setDataSource(ds);
//指定mapper xml目录
ResourcePatternResolver resolver = new PathMatchingResourcePatternResolver();
factoryBean.setMapperLocations(resolver.getResources("classpath:mapper2/*.xml"));
return factoryBean.getObject();
}
@Bean
public SqlSessionTemplate sqlSessionTemplate2() throws Exception {
SqlSessionTemplate template = new SqlSessionTemplate(sqlSessionFactory2()); // 使用上面配置的Factory
return template;
}
//关于事务管理器，不管是JPA还是JDBC等都实现自接口 PlatformTransactionManager
// 如果你添加的是 spring-boot-starter-jdbc 依赖，框架会默认注入 DataSourceTransactionManager 实例。
//在Spring容器中，我们手工注解@Bean 将被优先加载，框架不会重新实例化其他的 PlatformTransactionManager 实现类。
/*@Bean(name = "transactionManager2")
@Primary
public DataSourceTransactionManager masterTransactionManager() {
//MyBatis自动参与到spring事务管理中，无需额外配置，只要org.mybatis.spring.SqlSessionFactoryBean引用的数据源
// 与DataSourceTransactionManager引用的数据源一致即可，否则事务管理会不起作用。
return new DataSourceTransactionManager(ds);
}*/
}TxAdviceInterceptor.java和 TxAdvice2Interceptor.java中設定的事務管理器了；有需求的童鞋可以自己設定其他的事務管理器；(請參閱DruidConfig.java檢視)
新分散式業務測試介面JtaTestService.java和實作類別JtaTestServiceImpl.java其實就是一個很簡單的test01()方法，在該方法中我們分別先後呼叫
# classService.saveOrUpdateTClass(tClass);和teacherService.saveOrUpdateTeacher(teacher);
#在實作類別的方法中我使用的是：
@Transactional(transactionManager = "xatx", propagation = Propagation.REQUIRED, rollbackFor = { java.lang.RuntimeException.class })从而指定了使用哪个事务管理器，事务隔离级别(一般都用我这个默认的)，回滚的条件(一般可以使用Exception)，这三个可以自己根据业务实际修改；package com.zjt.service3;
import java.util.Map;
public interface JtaTestService {
public Map<String,Object> test01();
}package com.zjt.service3.impl;
import com.zjt.entity.TClass;
import com.zjt.entity.Teacher;
import com.zjt.service.TClassService;
import com.zjt.service2.TeacherService;
import com.zjt.service3.JtaTestService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Propagation;
import org.springframework.transaction.annotation.Transactional;
import java.util.LinkedHashMap;
import java.util.Map;
@Service("jtaTestServiceImpl")
public class JtaTestServiceImpl implements JtaTestService{
@Autowired
@Qualifier("teacherServiceImpl")
private TeacherService teacherService;
@Autowired
@Qualifier("tclassServiceImpl")
private TClassService tclassService;
@Override
@Transactional(transactionManager = "xatx", propagation = Propagation.REQUIRED, rollbackFor = { java.lang.RuntimeException.class })
public Map<String, Object> test01() {
LinkedHashMap<String,Object> resultMap=new LinkedHashMap<String,Object>();
TClass tClass=new TClass();
tClass.setName("8888");
tclassService.saveOrUpdateTClass(tClass);
Teacher teacher=new Teacher();
teacher.setName("8888");
teacherService.saveOrUpdateTeacher(teacher);
System.out.println(1/0);
resultMap.put("state","success");
resultMap.put("message","分布式事务同步成功");
return resultMap;
}
}
七、在test.ftl中增加一個按鈕來測試package com.zjt.web; import com.zjt.service3.JtaTestService; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.beans.factory.annotation.Qualifier; import org.springframework.stereotype.Controller; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.ResponseBody; import java.util.LinkedHashMap; import java.util.Map; @Controller @RequestMapping("/jtaTest") public class JtaTestContoller { @Autowired @Qualifier("jtaTestServiceImpl") private JtaTestService taTestService; @ResponseBody @RequestMapping("/test01") public Map<String,Object> test01(){ LinkedHashMap<String,Object> resultMap=new LinkedHashMap<String,Object>(); try { return taTestService.test01(); }catch (Exception e){ resultMap.put("state","fail"); resultMap.put("message","分布式事务同步失败"); return resultMap; } } }登入後複製
//分布式事务测试
$("#JTATest").click(function(){
$.ajax({
type: "POST",
url: "${basePath!}/jtaTest/test01",
data: {} ,
async: false,
error: function (request) {
layer.alert("与服务器连接失败/(ㄒoㄒ)/~~");
return false;
},
success: function (data) {
if (data.state == 'fail') {
layer.alert(data.message);
return false;
}else if(data.state == 'success'){
layer.alert(data.message);
}
}
});
});
<button class="layui-btn" id="JTATest">同时向班级和老师表插入名为8888的班级和老师</button>
當正常執行了sql語句之後，我們可以發現資料庫並沒有變化，因為整個方法的事務還沒走完，當我們走到1/0這步時：
在
方法中會將交易全部回滾：
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