想问一下这段代码有什么作用

public class FlinkSqlTemplateJob{

static {
    try {
        Class.forName("com.mysql.cj.jdbc.Driver");
    } catch (ClassNotFoundException e) {
        e.printStackTrace();
    }
}

public static void main(String[] args) throws Exception {
    ParameterTool parameterTool = ParameterTool.fromArgs(args);

    StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();

    env.enableCheckpointing(60 * 1000L);
    //每一分钟触发一次checkpoint保存状态
    env.getCheckpointConfig().setCheckpointingMode(CheckpointingMode.EXACTLY_ONCE);
    //checkpoint 语义设置为EXACTLY_ONCE，默认语义
    env.getCheckpointConfig().setMaxConcurrentCheckpoints(1);
    //同一时间内只能允许有一个checkpoint

    StreamTableEnvironment tableEnv = StreamTableEnvironment.create(env);
    tableEnv.getConfig().setSqlDialect(SqlDialect.DEFAULT);

    //数据源
    String sourceTableSql = parameterTool.get("sourceTableSql");
    //目标表
    String targetTableSql = parameterTool.get("targetTableSql");
    String insertSql = parameterTool.get("insertSql");

    if (StringUtils.isBlank(sourceTableSql)
            || StringUtils.isBlank(targetTableSql) || StringUtils.isBlank(insertSql)) {
        return;
    }

    for (String sql : sourceTableSql.split(";")) {
        tableEnv.executeSql(sql);
    }


    tableEnv.executeSql(targetTableSql);

    tableEnv.executeSql(insertSql);
}

}

这段是flink将原sql的数据插入到目标流中。

具体详情可以看我的Flink专栏
https://blog.csdn.net/qq_15604349/category_11734572.html

不懂帮顶。