Java executorservice 正在关闭，即使它的线程正在运行

Question

我正在使用 Executorsevice 从数据库生成文件。我正在使用 jdbc 和 core java 将表数据放入文件中。

创建具有 10 个线程的 Executorservice 后，我在 for 循环中提交 60 个线程以并行获取 60 个文件。这对于小数据和列数较少的表来说效果很好。但是，如果文件很大且表具有更多列，则在其他线程完成时，正在处理巨大表数据/更多列表的线程将停止，而不会在日志中提供任何信息。

ExecutorService executor = Executors.newFixedThreadPool(THREAD_COUNT);
        for (String filename : filenames) {
            EachFileThread worker = new EachFileThread(destdir, converter,
                    filename, this);
            executor.execute(worker);
        }
        executor.shutdown();

在每个文件线程中，我正在读取 xml 并获取列、表并形成查询，然后执行查询、格式化数据并将数据放入文件中

    forTable = (FileData) converter.convertFromXMLToObject( filename + ".xml");
    String query = getQuery(forTable);
    statement = connection.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE, ResultSet.CONCUR_READ_ONLY);
    resultSet = statement.executeQuery(query);
resultSet.setFetchSize(3000);
    WriteData(resultSet, filepath, forTable);(formatting the data from db and then writing to a file)

Answer 1

问题是您没有等待所有作业完成它们正在做的事情。正如 @msandiford 在评论中建议的那样，您应该添加对 awaitTermination(..) 的调用调用shutdown()后正如 https://docs.oracle.com/javase/7/docs/api/java/util/concurrent/ExecutorService.html 上的示例 shutdownAndAwaitTermination() 方法所示

例如，您可以尝试这样做:

ExecutorService executor = Executors.newFixedThreadPool(THREAD_COUNT);
for (String filename : filenames) {
    EachFileThread worker = new EachFileThread(destdir, converter, filename, this);
    executor.execute(worker);
}
executor.shutdown();
try {
    // Wait a while for existing tasks to terminate
    if (!executor.awaitTermination(60, TimeUnit.SECONDS)) {
        executor.shutdownNow(); // Cancel currently executing tasks
        // Wait a while for tasks to respond to being cancelled
        if (!executor.awaitTermination(60, TimeUnit.SECONDS))
            System.err.println("Executor did not terminate");
    }
} catch (InterruptedException ie) {
    // (Re-)Cancel if current thread also interrupted
    executor.shutdownNow();
    // Preserve interrupt status
    Thread.currentThread().interrupt();
}