elastic-job原始碼（1）- job自動裝配

public void init() {
    log.debug("Elastic job: zookeeper registry center init, server lists is: {}.", zkConfig.getServerLists());
    CuratorFrameworkFactory.Builder builder = CuratorFrameworkFactory.builder()
            //設定zookeeper 伺服器地址
            .connectString(zkConfig.getServerLists())
            //設定重試機制
            .retryPolicy(new ExponentialBackoffRetry(zkConfig.getBaseSleepTimeMilliseconds(), zkConfig.getMaxRetries(), zkConfig.getMaxSleepTimeMilliseconds()))
            //設定名稱空間，zookeeper節點名稱
            .namespace(zkConfig.getNamespace());
    //設定session超時時間
    if (0 != zkConfig.getSessionTimeoutMilliseconds()) {
        builder.sessionTimeoutMs(zkConfig.getSessionTimeoutMilliseconds());
    }
    //設定連線超時時間
    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<ACL> getDefaultAcl() {
                        return ZooDefs.Ids.CREATOR_ALL_ACL;
                    }
                
                    @Override
                    public List<ACL> getAclForPath(final String path) {
                        return ZooDefs.Ids.CREATOR_ALL_ACL;
                    }
                });
    }
    client = builder.build();
    //zookeeper 使用者端開始啟動
    client.start();
    try {
        //zookeeper 使用者端一直連線
        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 為tracingDataSource的job資料庫連線資訊
public DataSource tracingDataSource(final TracingProperties tracingProperties) {
    //獲取elastic-job 資料庫設定
    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<DataSource> tracingConfiguration(final DataSource dataSource, @Nullable final DataSource tracingDataSource) {
    /**
     * dataSource 是業務資料庫
     * tracingDataSource 是job資料庫
     * 當設定elasticjob.tracing.type = RDB時，如果單獨設定job資料庫是，預設使用job資料庫作為job執行軌跡的記錄
     * 但這邊同時業務資料庫和job追蹤資料庫同時注入是，mybatis-plus 結合@Table 使用的時候，很有可能找不到正確對應的資料來源
     */
    DataSource ds = tracingDataSource;
    if (ds == null) {
        ds = dataSource;
    }
    return new TracingConfiguration<>("RDB", ds);
}

public void createJobBootstrapBeans() {
    //獲取job設定
    ElasticJobProperties elasticJobProperties = applicationContext.getBean(ElasticJobProperties.class);
    //獲取單利註冊物件
    SingletonBeanRegistry singletonBeanRegistry = ((ConfigurableApplicationContext) applicationContext).getBeanFactory();
    //獲取注入zookeeper 使用者端
    CoordinatorRegistryCenter registryCenter = applicationContext.getBean(CoordinatorRegistryCenter.class);
    //獲取job事件追蹤
    TracingConfiguration<?> tracingConfig = getTracingConfiguration();
    //構造JobBootstraps
    constructJobBootstraps(elasticJobProperties, singletonBeanRegistry, registryCenter, tracingConfig);
}

private void constructJobBootstraps(final ElasticJobProperties elasticJobProperties, final SingletonBeanRegistry singletonBeanRegistry,
                                    final CoordinatorRegistryCenter registryCenter, final TracingConfiguration<?> tracingConfig) {
    //遍歷設定的每一個job
    for (Map.Entry<String, ElasticJobConfigurationProperties> entry : elasticJobProperties.getJobs().entrySet()) {
        ElasticJobConfigurationProperties jobConfigurationProperties = entry.getValue();
        //校驗 job class 和 type 都為空拋異常
        Preconditions.checkArgument(null != jobConfigurationProperties.getElasticJobClass()
                        || !Strings.isNullOrEmpty(jobConfigurationProperties.getElasticJobType()),
                "Please specific [elasticJobClass] or [elasticJobType] under job configuration.");
        //校驗 job class 和 type 都有 報相互排斥
        Preconditions.checkArgument(null == jobConfigurationProperties.getElasticJobClass()
                        || Strings.isNullOrEmpty(jobConfigurationProperties.getElasticJobType()),
                "[elasticJobClass] and [elasticJobType] are mutually exclusive.");


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