java - 我无法写入我创建的文本文件

Question

我创建了一个带有一些标题的文本文件，然后将其关闭，之后当我有要写入该文件的数据时，什么也没有发生，我的代码在下面，当我尝试打印到它时得到的堆栈跟踪.

public class Writetofile {

    BufferedWriter writer = null;

    public void recordData(String record) throws IOException {

        try {
            writer.append(record);
            writer.newLine();
            writer.close();
        } catch (Exception e) {e.printStackTrace();
        }
    }

    public void createtxtfile(String[] details) throws IOException {
        String machine = details[0];
        String date = details[1];
        String start_time = details[2];
        try {
            File new_cal = new File("C:\\Activity_Calibrator\\log\\" + machine + "//" + machine + ".txt");
            new_cal.getParentFile().mkdirs();
            FileWriter fwriter = new FileWriter(new_cal);
            writer = new BufferedWriter(fwriter);
            writer.append("Linear Calibration for " + machine + " carried out " + date);
            writer.newLine();
            writer.close();
        } catch (Exception e) {
        }
    }
}

Message that is recieved
java.io.IOException: Stream closed
  at java.io.BufferedWriter.ensureOpen(BufferedWriter.java:116)
  at java.io.BufferedWriter.write(BufferedWriter.java:221)
  at java.io.Writer.write(Writer.java:157)
  at java.io.Writer.append(Writer.java:227)
  at Writetofile.recordData(Writetofile.java:27)
  at UserInterFace.update(UserInterFace.java:75)
  at Comms.serialEvent(Comms.java:124)
  at gnu.io.RXTXPort.sendEvent(RXTXPort.java:732)
  at gnu.io.RXTXPort.eventLoop(Native Method)
  at gnu.io.RXTXPort$MonitorThread.run(RXTXPort.java:1575)

这很难理解，因为我读到我应该总是在写入 Stream 之后关闭它。

Answer 1

nothing happens, and I do not get an error

好的第一步是不要吞下异常——例如，您可以将堆栈跟踪打印到控制台:

} catch (Exception e) {
    e.printStackTrace();
}

然后您将收到一条正确的异常消息，这应该可以帮助您找到问题。