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

import java.util.Scanner;

public class ScannerDemo {
    public static void main(String[] arguments){
        Scanner input = new Scanner(System.in);

        String username;
        double age;
        String gender;
        String marital_status;
        int telephone_number;

        // Allows a person to enter his/her name   
        Scanner one = new Scanner(System.in);
        System.out.println("Enter Name:" );  
        username = one.next();
        System.out.println("Name accepted " + username);

        // Allows a person to enter his/her age   
        Scanner two = new Scanner(System.in);
        System.out.println("Enter Age:" );  
        age = two.nextDouble();
        System.out.println("Age accepted " + age);

        // Allows a person to enter his/her gender  
        Scanner three = new Scanner(System.in);
        System.out.println("Enter Gender:" );  
        gender = three.next();
        System.out.println("Gender accepted " + gender);

        // Allows a person to enter his/her marital status
        Scanner four = new Scanner(System.in);
        System.out.println("Enter Marital status:" );  
        marital_status = four.next();
        System.out.println("Marital status accepted " + marital_status);

        // Allows a person to enter his/her telephone number
        Scanner five = new Scanner(System.in);
        System.out.println("Enter Telephone number:" );  
        telephone_number = five.nextInt();
        System.out.println("Telephone number accepted " + telephone_number);
    }
}

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 ()); ｝

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);

import java.util.Scanner;  // Import the Scanner class

class Main { // Main is the class name
  public static void main(String[] args) {
    Scanner myObj = new Scanner(System.in);  // Create a Scanner object
    System.out.println("Enter username");

    String userName = myObj.nextLine();  // Read user input
    System.out.println("Username is: " + userName);  // Output user input
  }
}

您可以编写一个简单的程序来询问用户的姓名，并打印任何回复使用的输入。

或者要求用户输入两个数字，您可以对这些数字进行加、乘、减或除，并像计算器一样打印用户输入的答案。

这里你需要Scanner类。你必须导入java.util.Scanner;，并且在你需要使用的代码中:

Scanner input = new Scanner(System.in);

Input是一个变量名。

Scanner input = new Scanner(System.in);

System.out.println("Please enter your name: ");
s = input.next(); // Getting a String value

System.out.println("Please enter your age: ");
i = input.nextInt(); // Getting an integer

System.out.println("Please enter your salary: ");
d = input.nextDouble(); // Getting a double

看看这有什么不同:input.next();， i = input.nextInt();， d = input.nextDouble();

根据String类型，int类型和double类型的变化方式与其他类型相同。不要忘记代码顶部的import语句。