一文读懂Java怎么用键盘输入

极悦小编告诉大家，在Java中接受键盘输入是使用 Scanner 对象完成的。

考虑以下陈述

Scanner console = new Scanner(System.in)

该语句声明了一个名为 console 的引用变量。Scanner 对象与标准输入设备 (System.in) 相关联。

要从键盘获取输入，您可以调用 Scanner 类的方法。例如在以下语句中 Scanner 的 nextInt() 方法接受一个整数并返回变量 x ：

int x = console.nextInt();

例子 ：

import java.util.Scanner;    // Needed for Scanner class
/**
 *  This program demonstrates keyboard input.
 */
public class RectangleArea
{
   public static void main(String[] args)
   {
      int length;    // To hold rectangle's length.
      int width;     // To hold rectangle's width.
      int area;      // To hold rectangle's area
      // Create a Scanner object to read input.
      Scanner console = new Scanner(System.in);
      // Get length from the user.
      System.out.print("Enter length ");
      length = console.nextInt();
      // Get width from the user.
      System.out.print("Enter width ");
      width = console.nextInt();
      // Calculate area.
      area = length * width;
      // Display area.
      System.out.println("The area of rectangle is " + area);
   }
}

输出 ：

输入长度5
输入宽度8
矩形的面积是40

Scanner 类的其他一些有用的方法

例子 ：

import java.util.Scanner;
/**
 * This program demonstrates various Scanner methods.
 */
public class ReadEmployee
{
    public static void main(String[] args)
    {
        String name; // To hold the employee's name
        int age; // To hold the employee's age
        char gender; // To hold the employee's gender
        double salary; // To hold the employee's salary
        // Create a Scanner object to read input.
        Scanner console = new Scanner(System.in);
        // Get the employee's name
        System.out.print("Enter name: ");
        name = console.nextLine();
        // Get the employee's age
        System.out.print("Enter age: ");
        age = console.nextInt();
        // Get the employee's gender
        System.out.print("Enter gender: ");
        gender = console.next().charAt(0);
        // Get the employee's salary
        System.out.print("Enter salary: ");
        salary = console.nextDouble();
        // Display the information
        System.out.println("Name: " + name + " Age: " + age + " Gender: "
                + gender + " Salary: " + salary);
    }
}

输出 ：

输入姓名：Alex Joseph
输入年龄：24
输入性别：M
输入薪水：8000
姓名：Alex Joseph 年龄：24 性别：M 薪水：8000.0