你可以在Java中使用Scanner类

Scanner scan = new Scanner(System.in);
String s = scan.nextLine();
System.out.println("String: " + s);

你可以流动这段代码:

Scanner obj= new Scanner(System.in);
String s = obj.nextLine();

从控制台读取数据

BufferedReader is synchronized, so read operations on a BufferedReader can be safely done from multiple threads. The buffer size may be specified, or the default size(8192) may be used. The default is large enough for most purposes. readLine() « just reads data line by line from the stream or source. A line is considered to be terminated by any one these: \n, \r (or) \r\n Scanner breaks its input into tokens using a delimiter pattern, which by default matches whitespace(\s) and it is recognised by Character.isWhitespace. « Until the user enters data, the scanning operation may block, waiting for input. « Use Scanner(BUFFER_SIZE = 1024) if you want to parse a specific type of token from a stream. « A scanner however is not thread safe. It has to be externally synchronized. next() « Finds and returns the next complete token from this scanner. nextInt() « Scans the next token of the input as an int.

Code

String name = null;
int number;

java.io.BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
name = in.readLine(); // If the user has not entered anything, assume the default value.
number = Integer.parseInt(in.readLine()); // It reads only String,and we need to parse it.
System.out.println("Name " + name + "\t number " + number);

java.util.Scanner sc = new Scanner(System.in).useDelimiter("\\s");
name = sc.next();  // It will not leave until the user enters data.
number = sc.nextInt(); // We can read specific data.
System.out.println("Name " + name + "\t number " + number);

// The Console class is not working in the IDE as expected.
java.io.Console cnsl = System.console();
if (cnsl != null) {
    // Read a line from the user input. The cursor blinks after the specified input.
    name = cnsl.readLine("Name: ");
    System.out.println("Name entered: " + name);
}

流的输入和输出

Reader Input:     Output:
Yash 777          Line1 = Yash 777
     7            Line1 = 7

Scanner Input:    Output:
Yash 777          token1 = Yash
                  token2 = 777

下面是执行所需操作的完整类:

import java.util.Scanner;

public class App {
    public static void main(String[] args) {
        Scanner input = new Scanner(System.in);
        final int valid = 6;

        Scanner one = new Scanner(System.in);
        System.out.println("Enter your username: ");
        String s = one.nextLine();

        if (s.length() < valid) {
            System.out.println("Enter a valid username");
            System.out.println(
                "User name must contain " + valid + " characters");
            System.out.println("Enter again: ");
            s = one.nextLine();
        }

        System.out.println("Username accepted: " + s);

        Scanner two = new Scanner(System.in);
        System.out.println("Enter your age: ");
        int a = two.nextInt();
        System.out.println("Age accepted: " + a);

        Scanner three = new Scanner(System.in);
        System.out.println("Enter your sex: ");
        String sex = three.nextLine();
        System.out.println("Sex accepted: " + sex);
    }
}

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
  }
}

你写过

Scanner = input()

这是错误的方法，你必须创建一个整数或字符串，我更喜欢字符串，然后给一个字符串任意的名字，可以是I可以是n，或者其他的，记住你是在给用户名取名字你也可以给名字取用户名，代码是

String username = sc.nextline();
System.our.println("the username is" + username);

我希望你现在明白了