I/O
Scanner
监视器, 功能最强大的输入类, new Scanner(System.in)
Format
System.out.printf(): 静态创建格式化字符串
File
Read
用 File 对象构造一个 Scanner 对象: new Scanner(Paths.get("FileName"))(反斜杠需双写)
Write
用文件名构造一个 PrintWriter 对象:
new PrintWriter("FileName"), 之后调用System.PrintWriter.print方法.
Input
InputStream类:read(字节)Reader类:read(char)
Output
OutputStream类:write、flush、closeWriter类:write(char, String)、flush、close