Scanner means in java

Scanner in Java is an input tool for reading data from user input. It is mainly used to parse different types of data such as strings, numbers, Boolean values, etc., and to use delimiters to separate input data into different fields. To use the Scanner class, you need to create a Scanner object to specify the input stream, use the corresponding method to read the data, check whether there is more input, and close the object.

The meaning of Scanner in Java

In the Java programming language, the Scanner class is a Input tool for reading data from input. It allows developers to read a variety of data types, including strings, numbers, and Boolean values.

Main functions

The Scanner class provides the following main functions:

• Read data from the standard input stream:This class uses System.in as its default input stream, allowing developers to read data from the console or other standard input sources.

• Parse different types of data: Scanner can parse various data types, including:

  • String
  • Number ( int, long, float, double)
  • Boolean value
  • Date and time
• Use separator: Developers can Use delimiters to separate input data into different fields or tags. The default delimiter is a space or newline, but developers can specify their own delimiters.
• Skip input: The Scanner class provides methods to skip specific input, such as comments or newlines.

Usage method

To use the Scanner class, developers need to perform the following steps:

1. Create a Scanner object, and Specify the input stream (usually System.in):

<code class="java">Scanner scanner = new Scanner(System.in);</code>

2. Use the appropriate method to read data from the input:

<code class="java">String name = scanner.nextLine(); // 读取字符串
int age = scanner.nextInt(); // 读取整数</code>

3. Use hasNext () method checks if there is more input:

<code class="java">if (scanner.hasNext()) {
    // 读取更多输入
}</code>

4. Close the Scanner object to release system resources:

<code class="java">scanner.close();</code>

Sample code

The following code example demonstrates how to use the Scanner class to read user input from the console:

<code class="java">import java.util.Scanner;

public class ScannerExample {

    public static void main(String[] args) {
        // 创建一个Scanner对象
        Scanner scanner = new Scanner(System.in);

        // 读取用户输入
        System.out.println("请输入你的姓名：");
        String name = scanner.nextLine();
        System.out.println("请输入你的年龄：");
        int age = scanner.nextInt();

        // 打印结果
        System.out.println("姓名：" + name);
        System.out.println("年龄：" + age);

        // 关闭Scanner对象
        scanner.close();
    }
}</code>

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