java - 将多行读入Java中的扫描仪对象

Question

我在弄清楚如何将多行用户输入读取到扫描仪中，然后将其存储到单个字符串中时遇到了一些麻烦。到目前为止，我所拥有的在下面:

public static String getUserString(Scanner keyboard) { 
    System.out.println("Enter Initial Text:");
    String input = "";
    String nextLine = keyboard.nextLine();
    while(keyboard.hasNextLine()){
        input += keyboard.nextLine
    };
    return input;
}

那么main方法的前三个语句是:

Scanner scnr = new Scanner(System.in);
String userString = getUserString(scnr);  
System.out.println("\nCurrent Text: " + userString );

我的目标是让它在用户键入他们的文本后，他们所要做的就是按两次 Enter 键，他们键入的所有内容都会显示在他们面前(在“当前文本:”之后)。我还需要将字符串存储在 main 中的变量 userString 中(我必须在其他方法中使用此变量)。对此有任何帮助将不胜感激。它用于类，我们不能使用数组或 Stringbuilder 或任何比 while 循环和基本字符串方法复杂得多的东西。

谢谢!

Answer 1

使用BufferedReader:

BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
String input = "";
String line;
while((line = br.readLine()) != null){
    if(line.isEmpty()){
        break; // if an input is empty, break
    }
    input += line + "\n";
}
br.close();
System.out.println(input);

或者使用扫描仪:

String input = "";
Scanner keyboard = new Scanner(System.in);
String line;
while (keyboard.hasNextLine()) {
    line = keyboard.nextLine();
    if (line.isEmpty()) {
        break;
    }
    input += line + "\n";
}
System.out.println(input);

对于这两种情况，示例 I/O:

Welcome to Stackoverflow
Hello My friend
Its over now

Welcome to Stackoverflow
Hello My friend
Its over now

完整代码

public static void main (String[] args) {
    Scanner scnr = new Scanner(System.in);
    String userString = getUserString(scnr);  
    System.out.println("\nCurrent Text: " + userString);
}

public static String getUserString(Scanner keyboard) { 
    System.out.println("Enter Initial Text: ");
    String input = "";
    String line;
    while (keyboard.hasNextLine()) {
        line = keyboard.nextLine();
        if (line.isEmpty()) {
            break;
        }
        input += line + "\n";
    }
    return input;
}