Question

解决了，但我的声誉太低了，无法回答我自己的Q.

扫描仪输入; 扫描仪lineScanner;

input = new Scanner(System.in);
lineScanner = new Scanner(line);
String line;
char x;

askUserForInputFile();   //user selects input txt file. Method definitely works.

do {
    line = input.nextLine();
    if (line.length() < 6)
        continue;
        out.printf("debug0\n%s", line);   //<----problem

    do {
        out.print("debug1\n");
        x = lineScanner.next().charAt(0);   //<-----problem
        out.print("debug2\n");

//more code

我想从文件中逐行阅读并仅在其长度（）=＆gt;处理它时6.怎么了？

console：

  debug0
  Exception in thread "main" <scanned line, displayed correctly>debug
  java.util.NoSuchElementException

Answer 1

您需要在每次迭代开始时使用lineScanner重置lineScanner = new Scanner(line);。它目前正试图从你的第一行读入。

Answer 2

也许你想要这样的东西

public static File askUserForInputFile() throws IOException {
    System.out.println("Enter a file name: ");
    String filename = input.nextLine();

    return new File(fileName);
}

使用此处的方法

Scanner input = new Scanner(System.in);
File file = askUserForInputFile();

input = new Scanner(file);

Scanner lineScanner;
String line;
char x;

while (input.hasNextLine()) {
    String line = input.nextLine();

    if (line.length() < 6)
        out.printf("debug0\n%s", line);
    else {
        out.print("debug1\n");
        x = lineScanner.next().charAt(0);   //<-----problem
        out.print("debug2\n");
    }  
}

扫描仪（线路）和扫描仪（System.in）行为不端/人为错误

2 个答案: