Java的键盘

从键盘输入int型：

import java.util.Scanner;
class Test{
	public static void main(String[] agrs){
		Scanner sc = new Scanner(System.in);
		int ch = sc.nextInt();
		System.out.println(ch);
	}
}

从键盘输入字符串：

import java.util.Scanner;
class Test{
	public static void main(String[] agrs){
		Scanner sc = new Scanner(System.in);
		String ch = sc.next();
		System.out.println(ch);
	}
}

大小写转换：

import java.util.Scanner;
class Test{
	public static void main(String[] agrs){
		Scanner sc = new Scanner(System.in);
 		String ch1 = sc.next();
 		String ch2 = sc.next();
 		System.out.println(ch1.toUpperCase());//输入小写转大写
 		System.out.println(ch2.toLowerCase());//输入大写转小写
	}
}

输出多位小数：

import java.util.Scanner;
class Test{
	public static void main(String[] agrs){
		Scanner sc = new Scanner(System.in);
		double ch = sc.nextDouble();
		System.out.println(String.format("%.2f",ch));// %.nf输出n位小数
	}
}