获取键盘输入

System.in.read()

import java.io.*;
public static void main(String [] args) throws IOException{ 
         char c = (char) System.in.read(); 
         System.out.println(c); 
} 

System.out.read()只能针对一个字符的获取，获取进来的变量的类型只能是char，需要转换变量类型。

InputStreamReader类和BufferedReader类

import java.io.*;
public static void main(String [] args) throws IOException{ 
           BufferedReader br = new BufferedReader(new InputStreamReader(System.in)); 
           String s = br.readLine(); 
           System.out.println(s); 
}

Scanner类

import java.util.Scanner;
public static void main(String [] args) { 
         Scanner sc = new Scanner(System.in); 
         String s = sc.nextLine();
         System.out.println(s); 
}