How to use the findInLine() method of the Scanner class to find a specified string in user input

How to use the findInLine() method of the Scanner class to find a specified string in user input

The Scanner class is a commonly used input processing class in Java. It provides a variety of methods to read from the input stream. Get data. Among them, the findInLine() method can be used to find the specified string in user input. This article will introduce how to use the findInLine() method of the Scanner class, and attach corresponding code examples.

Before you start using the findInLine() method of the Scanner class, you first need to clarify the following points:

1. You must first create a Scanner object and bind it to an input source on, such as standard input System.in or file input.
2. The user's input must have content, that is, the Scanner object must be able to read data from the input source.
3. The string to be searched must be continuous without gaps.

The following is a code example that uses the findInLine() method of the Scanner class to find a specified string in user input:

import java.util.Scanner;

public class FindInLineExample {
    public static void main(String[] args) {
        // 创建Scanner对象，并绑定到标准输入System.in
        Scanner scanner = new Scanner(System.in);
        
        // 提示用户输入
        System.out.println("请输入一个字符串：");
        
        // 读取用户输入的字符串
        String input = scanner.nextLine();
        
        // 提示用户输入要查找的字符串
        System.out.println("请输入要查找的字符串：");
        
        // 读取用户输入的要查找的字符串
        String searchStr = scanner.nextLine();
        
        // 使用findInLine()方法查找字符串，并输出结果
        String result = scanner.findInLine(searchStr);
        if (result != null) {
            System.out.println("找到了指定的字符串：" + result);
        } else {
            System.out.println("未找到指定的字符串");
        }
        
        // 关闭Scanner对象
        scanner.close();
    }
}

Run the above code, the program will first prompt the user to enter a string before prompting the user for the string to be found. Next, the program will use the findInLine() method to find the specified string in the string entered by the user and output the result. If the specified string is found, "Specified string found:" plus the found string will be output, otherwise "Specified string not found" will be output.

It should be noted that the findInLine() method will only search for the specified string in the input part, not the entire input. Even if there are multiple parts of the entire input that match the specified string, the findInLine() method will only return the first matching part. If you want to find all matching parts, you can use regular expressions and the findInLine(Pattern) method to achieve this.

Summary:
This article introduces how to use the findInLine() method of the Scanner class to find a specified string in user input. By creating a Scanner object and binding it to the input source, reading the string entered by the user, and using the findInLine() method to find the specified string, you can easily process and search user input. I hope the sample code in this article will be helpful to readers' learning and practical application.

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