elastic-job源码（1）- job自动装配

public void init() {
    log.debug("Elastic job: zookeeper registry center init, server lists is: {}.", zkConfig.getServerLists());
    CuratorFrameworkFactory.Builder builder = CuratorFrameworkFactory.builder()
            //设置zookeeper 服务器地址
            .connectString(zkConfig.getServerLists())
            //设置重试机制
            .retryPolicy(new ExponentialBackoffRetry(zkConfig.getBaseSleepTimeMilliseconds(), zkConfig.getMaxRetries(), zkConfig.getMaxSleepTimeMilliseconds()))
            //设置命名空间，zookeeper节点名称
            .namespace(zkConfig.getNamespace());
    //设置session超时时间
    if (0 != zkConfig.getSessionTimeoutMilliseconds()) {
        builder.sessionTimeoutMs(zkConfig.getSessionTimeoutMilliseconds());
    }
    //设置连接超时时间
    if (0 != zkConfig.getConnectionTimeoutMilliseconds()) {
        builder.connectionTimeoutMs(zkConfig.getConnectionTimeoutMilliseconds());
    }
    if (!Strings.isNullOrEmpty(zkConfig.getDigest())) {
        builder.authorization("digest", zkConfig.getDigest().getBytes(StandardCharsets.UTF_8))
                .aclProvider(new ACLProvider() {
                
                    @Override
                    public List getDefaultAcl() {
                        return ZooDefs.Ids.CREATOR_ALL_ACL;
                    }
                
                    @Override
                    public List getAclForPath(final String path) {
                        return ZooDefs.Ids.CREATOR_ALL_ACL;
                    }
                });
    }
    client = builder.build();
    //zookeeper 客户端开始启动
    client.start();
    try {
        //zookeeper 客户端一直连接
        if (!client.blockUntilConnected(zkConfig.getMaxSleepTimeMilliseconds() * zkConfig.getMaxRetries(), TimeUnit.MILLISECONDS)) {
            client.close();
            throw new KeeperException.OperationTimeoutException();
        }
        //CHECKSTYLE:OFF
    } catch (final Exception ex) {
        //CHECKSTYLE:ON
        RegExceptionHandler.handleException(ex);
    }
}

/**
 * Create a bean of tracing DataSource.
 *
 * @param tracingProperties tracing Properties
 * @return tracing DataSource
 */
@Bean("tracingDataSource")
//spring中注入bean name 为tracingDataSource的job数据库连接信息
public DataSource tracingDataSource(final TracingProperties tracingProperties) {
    //获取elastic-job 数据库配置
    DataSourceProperties dataSource = tracingProperties.getDataSource();
    if (dataSource == null) {
        return null;
    }
    HikariDataSource tracingDataSource = new HikariDataSource();
    tracingDataSource.setJdbcUrl(dataSource.getUrl());
    BeanUtils.copyProperties(dataSource, tracingDataSource);
    return tracingDataSource;
}


/**
 * Create a bean of tracing configuration.
 *
 * @param dataSource required by constructor
 * @param tracingDataSource tracing ataSource
 * @return a bean of tracing configuration
 */
@Bean
@ConditionalOnBean(DataSource.class)
@ConditionalOnProperty(name = "elasticjob.tracing.type", havingValue = "RDB")
public TracingConfiguration tracingConfiguration(final DataSource dataSource, @Nullable final DataSource tracingDataSource) {
    /**
     * dataSource 是业务数据库
     * tracingDataSource 是job数据库
     * 当配置elasticjob.tracing.type = RDB时，如果单独配置job数据库是，默认使用job数据库作为job运行轨迹的记录
     * 但这边同时业务数据库和job追踪数据库同时注入是，mybatis-plus 结合@Table 使用的时候，很有可能找不到正确对应的数据源
     */
    DataSource ds = tracingDataSource;
    if (ds == null) {
        ds = dataSource;
    }
    return new TracingConfiguration("RDB", ds);
}

public void createJobBootstrapBeans() {
    //获取job配置
    ElasticJobProperties elasticJobProperties = applicationContext.getBean(ElasticJobProperties.class);
    //获取单利注册对象
    SingletonBeanRegistry singletonBeanRegistry = ((ConfigurableApplicationContext) applicationContext).getBeanFactory();
    //获取注入zookeeper 客户端
    CoordinatorRegistryCenter registryCenter = applicationContext.getBean(CoordinatorRegistryCenter.class);
    //获取job事件追踪
    TracingConfiguration> tracingConfig = getTracingConfiguration();
    //构造JobBootstraps
    constructJobBootstraps(elasticJobProperties, singletonBeanRegistry, registryCenter, tracingConfig);
}

private void constructJobBootstraps(final ElasticJobProperties elasticJobProperties, final SingletonBeanRegistry singletonBeanRegistry,
                                    final CoordinatorRegistryCenter registryCenter, final TracingConfiguration> tracingConfig) {
    //遍历配置的每一个job
    for (Map.Entry entry : elasticJobProperties.getJobs().entrySet()) {
        ElasticJobConfigurationProperties jobConfigurationProperties = entry.getValue();
        //校验 job class 和 type 都为空抛异常
        Preconditions.checkArgument(null != jobConfigurationProperties.getElasticJobClass()
                        || !Strings.isNullOrEmpty(jobConfigurationProperties.getElasticJobType()),
                "Please specific [elasticJobClass] or [elasticJobType] under job configuration.");
        //校验 job class 和 type 都有 报相互排斥
        Preconditions.checkArgument(null == jobConfigurationProperties.getElasticJobClass()
                        || Strings.isNullOrEmpty(jobConfigurationProperties.getElasticJobType()),
                "[elasticJobClass] and [elasticJobType] are mutually exclusive.");


        if (null != jobConfigurationProperties.getElasticJobClass()) {
            //通过class 注入job
            registerClassedJob(entry.getKey(), entry.getValue().getJobBootstrapBeanName(), singletonBeanRegistry, registryCenter, tracingConfig, jobConfigurationProperties);
        } else if (!Strings.isNullOrEmpty(jobConfigurationProperties.getElasticJobType())) {
            //通过type 注入job
            registerTypedJob(entry.getKey(), entry.getValue().getJobBootstrapBeanName(), singletonBeanRegistry, registryCenter, tracingConfig, jobConfigurationProperties);
        }
    }
}

@Override
public void run(final String... args) {
    log.info("Starting ElasticJob Bootstrap.");
    applicationContext.getBeansOfType(ScheduleJobBootstrap.class).values().forEach(ScheduleJobBootstrap::schedule);
    log.info("ElasticJob Bootstrap started.");
}