从 BufferedReader 读取会抛出异常，因为在创建新的 BufferedReader 后流关闭

Question

以下是一种方法，它接受用户的输入和 returns 响应。

private String getValueFromUser(String propertyValue){
    String response = ""; 
    try(BufferedReader br = new BufferedReader(new InputStreamReader(System.in))){
        response = br.readLine();
        if (response.equals("")){
            return propertyValue;
        }
    } catch (IOException e) {
        e.printStackTrace();
    }
    return response;
}

此方法在第一次调用时运行良好，但在后续调用中抛出以下异常。

java.io.IOException: Stream closed
at java.io.BufferedInputStream.getBufIfOpen(BufferedInputStream.java:170)
at java.io.BufferedInputStream.read(BufferedInputStream.java:336)
at sun.nio.cs.StreamDecoder.readBytes(StreamDecoder.java:284)
at sun.nio.cs.StreamDecoder.implRead(StreamDecoder.java:326)
at sun.nio.cs.StreamDecoder.read(StreamDecoder.java:178)
at java.io.InputStreamReader.read(InputStreamReader.java:184)
at java.io.BufferedReader.fill(BufferedReader.java:161)
at java.io.BufferedReader.readLine(BufferedReader.java:324)
at java.io.BufferedReader.readLine(BufferedReader.java:389)
at com.ripple.utility.ConfigurationUtility.getValueFromUser(ConfigurationUtility.java:119)
at com.ripple.utility.ConfigurationUtility.createPropertiesDTO(ConfigurationUtility.java:108)
at com.ripple.utility.ConfigurationUtility.setProperties(ConfigurationUtility.java:169)
at com.ripple.utility.ConfigurationUtility.main(ConfigurationUtility.java:191)

有人可以帮忙解释一下代码的问题吗？

Answer 1

当 BufferedReader 在 try-with-resources 块结束时关闭时，System.in 也关闭并且无法重新打开。

您应该打开 reader 一次，并在您可以使用它的地方保持打开状态，直到您的程序完成。

从 BufferedReader 读取会抛出异常，因为在创建新的 BufferedReader 后流关闭

Reading from BufferedReader throws exception as stream closed after creating a new BufferedReader

java

ioexception

bufferedreader