NumberFormatException For input string 怎么写非空操作

The error message "NumberFormatException: For input string: ""怎么写非空操作" indicates that there is an attempt to convert an empty string to a numeric value.

To fix this issue, you need to check if the string is empty before performing any numeric operations. Here's an example of how you can write a non-empty check in Java:

String input = ""; // The input string

if (!input.isEmpty()) {
    // Perform numeric operations here
    int number = Integer.parseInt(input);
    // ... rest of the code
} else {
    // Handle the case when the string is empty
    System.out.println("Input string is empty!");
}

In this example, the isEmpty() method is used to check if the string is empty. If the string is not empty, you can proceed with the numeric operations. Otherwise, you can handle the empty case appropriately