Cell 同时读取多个线程中的值

需要同时读取多个线程中的单元格值是一个常见的需求。本文介绍了如何为此目的使用 Aspose.Cells。

要同时读取多个线程中的单元格值，请设置Worksheet.getCells().setMultiThreadReading()到真的.如果不这样做，您可能会得到错误的单元格值。请注意，多线程不支持某些功能，例如格式化单元格值。所以 MultiThreadReading 只允许您访问单元格的原始数据。在多线程环境下，如果您尝试获取单元格的格式化值，例如通过 Cell.getStringValue() 获取数值，您可能会得到意外的结果或异常。

以下代码：

1. 创建工作簿。
2. 添加工作表。
3. 使用字符串值填充工作表。
4. 然后它创建两个同时从随机单元格中读取值的线程。 如果读取的值正确，则不会发生任何事情。如果读取的值不正确，则会显示一条消息。

如果您评论此行：

testWorkbook.getWorksheets().get(0).getCells().setMultiThreadReading(true);

然后显示以下消息：

if (s.equals("R" + row + "C" + col)!=true)

{

    System.out.println("This message box will show up when cells read values are incorrect.");

}

否则，程序运行时不会显示任何消息，这意味着从单元格读取的所有值都是正确的。

// For complete examples and data files, please go to https://github.com/aspose-cells/Aspose.Cells-for-Java

public abstract class ThreadProc implements Runnable {
	boolean isRunning = true;
	Workbook testWorkbook;
	Random r = new Random();

	public ThreadProc(Workbook workbook) {
		this.testWorkbook = workbook;
	}

	public int randomNext(int Low, int High) {
		int R = r.nextInt(High - Low) + Low;
		return R;
	}

	public void kill() {
		this.isRunning = false;
	}

	public void run() {

		while (this.isRunning) {
			int row = randomNext(0, 10000);
			int col = randomNext(0, 100);
			
			//Commonly you can only access Cell.Value instead of Cell.StringValue.
			//In this demo all cell values are string, so Cell.StringValue is same with Cell.Value here and can be used.
			//For other values such as numeric, if you call Cell.StringValue here, you may get unexpected result or exception here.
			//It is because that Cell.getStringValue() will format those values according to the number format but the formatting process
			//does not support multi-threads.
			String s = testWorkbook.getWorksheets().get(0).getCells().get(row, col).getStringValue();

			if (s.equals("R" + row + "C" + col) != true) {
				System.out.println("This message box will show up when cells read values are incorrect.");
			}
		}
	}

}

	// Main.Java

static void TestMultiThreadingRead() throws Exception {

    Workbook testWorkbook = new Workbook();
    testWorkbook.getWorksheets().clear();
    testWorkbook.getWorksheets().add("Sheet1");

    for (int row = 0; row < 10000; row++)
        for (int col = 0; col < 100; col++)
            testWorkbook.getWorksheets().get(0).getCells().get(row, col).setValue("R" + row + "C" + col);

    //Commenting this line will show a pop-up message
    testWorkbook.getWorksheets().get(0).getCells().setMultiThreadReading(true);

    ThreadProc tp = new ThreadProc(testWorkbook);

    Thread myThread1 = new Thread(tp);
    myThread1.start();

    Thread myThread2 = new Thread(tp);
    myThread2.start();

    Thread.currentThread().sleep(5*1000);
    tp.kill();
}