Java : How to read password from file?

Question

我正在使用System.console()以便读取用户密码。

我的代码:

    Console console = System.console();
    if (console == null) {
        throw new RuntimeException("No console is available for input");
    }

    System.out.print("Enter the password: ");
    String password = new String(console.readPassword());

当我直接运行它时，它工作正常(来自 Redhat )。

问题是当我尝试从文本文件读取密码时:

java -jar my_jar.jar < password.txt

我明白了:

No console is available for input.

如何解决？

Answer 1

此行为是预期的。引用自java.io.Console:

Whether a virtual machine has a console is dependent upon theunderlying platform and also upon the manner in which the virtualmachine is invoked. If the virtual machine is started from aninteractive command line without redirecting the standard input andoutput streams then its console will exist and will typically beconnected to the keyboard and display from which the virtual machinewas launched.

对于不使用Console的可能解决方案，您可以阅读此答案 Trying to read from the console in Java .

如果控制台存在，您可以继续使用它，如果不存在，则故障返回到 BufferedReader/Scanner。