JavaAPI——Scanner

1. 用户输入数据

Scanner s=new Scanner(System.in);
int i=s.nextInt();

2. 输入文件

   Scanner sc = new Scanner(new File("myNumbers"));while (sc.hasNextLong()) {
    long aLong = sc.nextLong();} 

3. 规定分隔符

使用了正则表达式，注意关闭扫描器

String input = "1 fish 2 fish red fish blue fish";
Scanner s = new Scanner(input).useDelimiter("\\s*fish\\s*");
System.out.println(s.nextInt());
System.out.println(s.nextInt());
System.out.println(s.next());
System.out.println(s.next());
s.close();
/* 1 2 red blue */

4. 使用MatchResult进行输出

这里一定要是正则匹配好的结果，不然不能输出

String input = "1 fish 2 fish red fish blue fish";
Scanner s = new Scanner(input);
s.findInLine("(\\d+) fish (\\d+) fish (\\w+) fish (\\w+)");
MatchResult result = s.match();
for (int i=1; i<=result.groupCount(); i++)System.out.println(result.group(i));
s.close();
/* 1 2 red blue */