tcc分布式事务源码解析系列(三)之启动详解
2017-10-13 本文已影响131人
dromara
启动源码详解
- 通过上面的二篇文章，我相信您对tcc应该有个大体的了解，并且已经搭建好了调试环境，那么就让我们一起探索tcc的源码之旅。
- 首先看任何框架的源码都需要找到框架的入口，tcc也不例外，还记得我们在项目中applicationContext.xml有一段这么的配置吗?
<!-- Aspect 切面配置，是否开启AOP切面-->
<aop:aspectj-autoproxy expose-proxy="true"/>
<!--扫描框架的包-->
<context:component-scan base-package="com.happylifeplat.tcc.*"/>
<!--启动类属性配置-->
<bean id="tccTransactionBootstrap" class="com.happylifeplat.tcc.core.bootstrap.TccTransactionBootstrap">
<property name="serializer" value="kryo"/>
<property name="coordinatorQueueMax" value="5000"/>
<property name="coordinatorThreadMax" value="4"/>
<property name="recoverDelayTime" value="120"/>
<property name="retryMax" value="3"/>
<property name="rejectPolicy" value="Abort"/>
<property name="blockingQueueType" value="Linked"/>
<property name="scheduledDelay" value="120"/>
<property name="scheduledThreadMax" value="4"/>
<property name="repositorySupport" value="db"/>
<property name="tccDbConfig">
<bean class="com.happylifeplat.tcc.common.config.TccDbConfig">
<property name="url"
value="jdbc:mysql://192.168.1.68:3306/account?useUnicode=true&characterEncoding=utf8"/>
<property name="driverClassName" value="com.mysql.jdbc.Driver"/>
<property name="password" value="Wgj@555888"/>
<property name="username" value="xiaoyu"/>
</bean>
</property>
</bean>
- 通过以上的配置我们知道首先需要开启Aop切面，再扫描框架的包，重点我们来关注 TccTransactionBootstrap
TccTransactionBootstrap 源码解析
package com.happylifeplat.tcc.core.bootstrap;
import com.happylifeplat.tcc.common.config.TccConfig;
import com.happylifeplat.tcc.core.helper.SpringBeanUtils;
import com.happylifeplat.tcc.core.service.TccInitService;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.context.ConfigurableApplicationContext;
import org.springframework.stereotype.Component;
@Component
public class TccTransactionBootstrap extends TccConfig implements ApplicationContextAware {
private final TccInitService tccInitService;
@Autowired
public TccTransactionBootstrap(TccInitService tccInitService) {
this.tccInitService = tccInitService;
}
@Override
public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
//保存spring的上下文
SpringBeanUtils.getInstance().setCfgContext((ConfigurableApplicationContext) applicationContext);
start(this);
}
private void start(TccConfig tccConfig) {
tccInitService.initialization(tccConfig);
}
}
-
它继承 TccConfig 能获取在xml配置的属性信息，实现 ApplicationContextAware 当spring容器初始化的时候，会自动的将ApplicationContext注入进来
-
我们继续跟踪代码，进入initialization 方法
public void initialization(TccConfig tccConfig) {
Runtime.getRuntime().addShutdownHook(new Thread(() -> LOGGER.error("系统关闭")));
try {
//加载spi配置，把spi的配置注入成spring的bean 方便后续的使用
//就是框架所支持的序列化，存储方式
LoadSpiSupport(tccConfig);
coordinatorService.start(tccConfig);
} catch (Exception ex) {
LogUtil.error(LOGGER, "tcc事务初始化异常:{}", ex::getMessage);
System.exit(1);//非正常关闭
}
LogUtil.info(LOGGER, () -> "Tcc事务初始化成功！");
}
-
LoadSpiSupport 采用jdk自带的spi加载，如果有不明白的小伙伴，可以自行google
-
我们继续进入 coordinatorService.start(tccConfig)
@Override
public void start(TccConfig tccConfig) throws Exception {
this.tccConfig = tccConfig;
//获取应用名称
final String appName = applicationService.acquireName();
//获取上一步加载的spi资源信息
coordinatorRepository = SpringBeanUtils.getInstance().getBean(CoordinatorRepository.class);
//初始化spi 协调资源存储
coordinatorRepository.init(appName, tccConfig);
//初始化 协调资源线程池
initCoordinatorPool();
//定时执行补偿
scheduledRollBack();
}
-
coordinatorRepository.init(appName, tccConfig) 就是根据spi思想来具体初始化，现在支持的如图：
-
initCoordinatorPool() 初始化 协调资源线程池
private void initCoordinatorPool() {
synchronized (LOGGER) {
//采用LinkedBlockingQueue
QUEUE = new LinkedBlockingQueue<>(tccConfig.getCoordinatorQueueMax());
final int coordinatorThreadMax = tccConfig.getCoordinatorThreadMax();
final TccTransactionThreadPool threadPool = SpringBeanUtils.getInstance().getBean(TccTransactionThreadPool.class);
//获取固定数量线程大小的线程池
final ExecutorService executorService = threadPool.newCustomFixedThreadPool(coordinatorThreadMax);
LogUtil.info(LOGGER, "启动协调资源操作线程数量为:{}", () -> coordinatorThreadMax);
for (int i = 0; i < coordinatorThreadMax; i++) {
//执行线程
executorService.execute(new Worker());
}
}
}
class Worker implements Runnable {
@Override
public void run() {
execute();
}
private void execute() {
while (true) {
try {
//阻塞队列获取
final CoordinatorAction coordinatorAction = QUEUE.take();
if (coordinatorAction != null) {
final int code = coordinatorAction.getAction().getCode();
if (CoordinatorActionEnum.SAVE.getCode() == code) {
save(coordinatorAction.getTccTransaction());
} else if (CoordinatorActionEnum.DELETE.getCode() == code) {
remove(coordinatorAction.getTccTransaction().getTransId());
} else if (CoordinatorActionEnum.UPDATE.getCode() == code) {
update(coordinatorAction.getTccTransaction());
}
}
} catch (Exception e) {
e.printStackTrace();
LogUtil.error(LOGGER, "执行协调命令失败：{}", e::getMessage);
}
}
}
}
- scheduledRollBack() 执行定时补偿，这个以后再详细讲解逻辑
