如何使用Scanner类从控制台读取输入?就像这样:

System.out.println("Enter your username: ");
Scanner = input(); // Or something like this, I don't know the code

基本上,我想要的只是让扫描器读取用户名的输入,并将输入分配给一个String变量。


当前回答

举个简单的例子:

import java.util.Scanner;

public class Example
{
    public static void main(String[] args)
    {
        int number1, number2, sum;

        Scanner input = new Scanner(System.in);

        System.out.println("Enter First multiple");
        number1 = input.nextInt();

        System.out.println("Enter second multiple");
        number2 = input.nextInt();

        sum = number1 * number2;

        System.out.printf("The product of both number is %d", sum);
    }
}

其他回答

读取输入: 扫描仪扫描仪=新的扫描仪(System.in); 字符串输入= scanner.nextLine(); 当你调用一个带有参数/形参的方法时读取输入: 如果(arg游戏。长度!= 2){ System.err。println(" utilzare: java Grep < filier > <cuvant>"); system . exit (1); } 尝试{ grep (args [0], arg游戏[1]); } catch (IOException e) { System.out.println (e.getMessage ()); }

import java.util.*;

class Ss
{
    int id, salary;
    String name;

   void Ss(int id, int salary, String name)
    {
        this.id = id;
        this.salary = salary;
        this.name = name;
    }

    void display()
    {
        System.out.println("The id of employee:" + id);
        System.out.println("The name of employye:" + name);
        System.out.println("The salary of employee:" + salary);
    }
}

class employee
{
    public static void main(String args[])
    {
        Scanner sc = new Scanner(System.in);

        Ss s = new Ss(sc.nextInt(), sc.nextInt(), sc.nextLine());
        s.display();
    }
}

举个简单的例子:

import java.util.Scanner;

public class Example
{
    public static void main(String[] args)
    {
        int number1, number2, sum;

        Scanner input = new Scanner(System.in);

        System.out.println("Enter First multiple");
        number1 = input.nextInt();

        System.out.println("Enter second multiple");
        number2 = input.nextInt();

        sum = number1 * number2;

        System.out.printf("The product of both number is %d", sum);
    }
}

当用户输入他/她的用户名时,也检查是否有有效的输入。

java.util.Scanner input = new java.util.Scanner(System.in);
String userName;
final int validLength = 6; // This is the valid length of an user name

System.out.print("Please enter the username: ");
userName = input.nextLine();

while(userName.length() < validLength) {

    // If the user enters less than validLength characters
    // ask for entering again
    System.out.println(
        "\nUsername needs to be " + validLength + " character long");

    System.out.print("\nPlease enter the username again: ");
    userName = input.nextLine();
}

System.out.println("Username is: " + userName);

说明java.util.Scanner如何工作的一个简单示例是从System.in中读取单个整数。这真的很简单。

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

要检索用户名,我可能会使用sc.nextLine()。

System.out.println("Enter your username: ");
Scanner scanner = new Scanner(System.in);
String username = scanner.nextLine();
System.out.println("Your username is " + username);

如果您想对输入进行更多控制,或者只是验证用户名变量,也可以使用next(字符串模式)。

你可以在java.util.Scanner的API文档中找到更多关于它们实现的信息