Java 异常处理和文件 I/O答案

【问题标题】：Java Exception Handling and File I/OJava 异常处理和文件 I/O
【发布时间】：2014-03-17 23:57:10
【问题描述】：

  [ I am out of ideas I need a to write a code that writes and reads text files within  theprocessfiles method and a code that counts and print the total number of borrowers As part of my home I need to write a class that writes and reads text files.


public void 

processFiles()throws FileNotFoundException
{
     [ I am struggling to write a code that actually reads and writes a text file to a windows explorer folder ]

    try
    { 
        System.out.println("Enter your Firstname");
        Scanner sc=new Scanner(System.in); 
        String firstName=sc.nextLine();   
        System.out.println("Enter your lastname");
        String lastName=sc.nextLine();
        System.out.println("Enter your library number"); 
        String libraryNumber=sc.nextLine(); 
        System.out.println("Enter the number of books on loan");
        int numberOfBooks=sc.nextInt();
        System.out.println(firstName  +" "+ lastName +" "+ libraryNumber +" "+ numberOfBooks);
        int count// I am struggling to to write a code that counts the borrowers and diplay it on the windows page.
        int total// I am struggling to to write a code that displays the total number of borrowers to the windows page.
        input.close();
        output.close();
    }
    catch (InputMismatchException e)  [This is the catch method]
    { 
        System.out.println("Invalid");
    }
    catch (Exception e) this is the catch method
    {

[这是catch语句] System.out.println("错误异常"); }

    input.close();[ this is the input close]
    output.close(); [and output close statements]
}

}

[如果有人可以帮助我，我将不胜感激。]

【问题讨论】：

标签： java javascript file-io exception-handling fileinputstream

【解决方案1】：

没有人可以为您编写完整的代码。不过，这里有一些提示：

Keep that link open at all times.

将扫描进程与I/O进程分离；使try 块尽可能小。

其次，要获取文件的路径，请使用Paths.get()：

final Path path = Paths.get(someString);

要检查文件是否存在，请使用：

Files.exists(path);

要打开阅读器以文本形式（非二进制）读取文件，请使用：

Files.newBufferedReader(path, StandardCharsets.UTF_8);

要打开写入器以将文件写入文本（非二进制），请使用：

Files.newBufferedWriter(path, StandardCharsets.UTF_8);

使用 try-with-resources 语句：

try (
    // open I/O resources here
) {
    // operate with said resources
} catch (FileSystemException e) {
    // fs error: permission denied, file does not exist, others
} catch (IOException e) {
    // Other I/O error
}

Java 在 try 块之后（即第一对大括号之后）立即为您关闭资源。

【讨论】：