java - 并行执行 : How to update Excel WorkBook using Synchronized method, 仅在同步方法执行完成后？

Question

我在类中编写了一个非静态同步方法，以避免多个线程同时更新 Excel 工作簿。例如，ID #9 和 #10 的线程正在尝试更新 Excel，预期 Thread#9 应该完成同步方法的操作，然后 Thread#10 应该能够调用我们没有发生的方法。下面是代码片段。

public synchronized boolean put(String parameterName, String parameterValue) {
    try {
        System.out.println("Start Time:= " + Thread.currentThread().getId() + " :: " + LocalDateTime.now().toString());
        updateData(data.get("XLFileName"), data.get("XLSheetName"), parameterName, parameterValue, data.get("TestCaseID"), data.get("Iteration"));
        System.out.println("End Time:= " + Thread.currentThread().getId() + " :: " + LocalDateTime.now().toString());
        return true;
    } catch (FilloException flex) {
        flex.printStackTrace();
        // extentTest.log(LogStatus.FATAL, "A", flex.getMessage());
        return false;
    }
}

public void updateData(String XLFileName, String XLSheet, String parameterName, String parameterValue, String testCaseID, String iteration) throws FilloException {
    Fillo fillo = new Fillo();
    Connection connection = fillo.getConnection(XLFileName);
    String strQuery = "Update " + XLSheet + " Set " + parameterName + "='" + parameterValue + "' where TestCaseID = '" + testCaseID + "' and Iteration = '" + iteration + "'";
    connection.executeUpdate(strQuery);
    connection.close();

    try {
        Thread.sleep(10000);
    } catch (InterruptedException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }

}

Current Output:

Start Time:= 10 :: 2017-03-20T15:03:31.041
1 row(s) affected
Start Time:= 9 :: 2017-03-20T15:03:31.619
1 row(s) affected
End Time:= 10 :: 2017-03-20T15:03:41.201
End Time:= 9 :: 2017-03-20T15:03:41.675

Expected Output:

Start Time:= 10 :: 2017-03-20T15:03:31.041
1 row(s) affected
End Time:= 10 :: 2017-03-20T15:03:41.201
Start Time:= 9 :: 2017-03-20T15:03:31.619
1 row(s) affected
End Time:= 9 :: 2017-03-20T15:03:41.675

也尝试过同步块(synchronized block)。

Answer 1

您可以尝试使用带锁的类同步块(synchronized block)，如下所示。

public synchronized boolean put(String parameterName, String parameterValue) {
    synchronized (DataBook.class) {
        try {
            System.out.println("Start Time:= " + Thread.currentThread().getId() + " :: " + LocalDateTime.now().toString());
            updateData(data.get("XLFileName"), data.get("XLSheetName"), parameterName, parameterValue, data.get("TestCaseID"), data.get("Iteration"));
            System.out.println("End Time:= " + Thread.currentThread().getId() + " :: "  + LocalDateTime.now().toString());
            return true;

        } catch (FilloException flex) {
            flex.printStackTrace();
            return false;
        }
    }
}