控制台输入类java.util.Scanner

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canner类最实用的地方表现在获取控制台输入。当通过new Scanner(System.in)创建一个Scanner，控制台会一直等待输入，把所输入的内容传给Scanner，作为扫描对象。如果要获取输入的内容，则只需要调用Scanner的nextLine()方法即可。

1 如何判断控制台输入结束？
按回车键是输入下一行，多行输入，要有个结束符标志，如下例子中的“exit”

[plain]
    public static void main(String[] args) {
        Scanner s = new Scanner(System.in);
        System.out.println("input files' name：");
        while (true) {
                String line = s.nextLine();
                if (line.equals("exit")) break;
                System.out.println(">>>" + line);
        } //end while
}

public static void main(String[] args) {
  Scanner s = new Scanner(System.in);
        System.out.println("input files' name：");
        while (true) {
                String line = s.nextLine();
                if (line.equals("exit")) break;
                System.out.println(">>>" + line);
        } //end while
}
2 Scanner默认使用空格作为分割符来分隔文本，但允许你指定新的分隔符

使用默认的空格分隔符：

[java]
      public static void main(String[] args) throws FileNotFoundException {
                Scanner s = new Scanner("123 asdf sd 45 789 sdf asdfl,sdf.sdfl,asdf    ......asdfkl    las");
//                s.useDelimiter(" |,|\\.");
                while (s.hasNext()) {
                        System.out.println(s.next());
                }
        }

        public static void main(String[] args) throws FileNotFoundException {
                Scanner s = new Scanner("123 asdf sd 45 789 sdf asdfl,sdf.sdfl,asdf    ......asdfkl    las");
//                s.useDelimiter(" |,|\\.");
                while (s.hasNext()) {
                        System.out.println(s.next());
                }
        }输出如下
[plain]
123
asdf
sd
45
789
sdf
asdfl,sdf.sdfl,asdf
......asdfkl
las

Process finished with exit code 0

123
asdf
sd
45
789
sdf
asdfl,sdf.sdfl,asdf
......asdfkl
las

Process finished with exit code 0将注释行去掉，使用空格或逗号或点号作为分隔符，输出结果如下：

[plain]
123
asdf
sd
45
789
sdf
asdfl
sdf
sdfl
asdf

asdfkl

las

Process finished with exit code 0

123
asdf
sd
45
789
sdf
asdfl
sdf
sdfl
asdf

asdfkl

las

Process finished with exit code 0