Java Error: Whitespace Error in Java11 Strings, How to Handle and Avoid

During Java programming, we may encounter characters in strings that are mistaken for spaces. This error is usually caused by invisible white space characters. There are many reasons for this error, but the solutions and ways to avoid it are all similar. This article will introduce the whitespace error in Java11 strings and how to deal with and avoid this error.

First, let us understand the cause of this error. In Java 11, there are four different whitespace characters in strings: space, newline, carriage return, and tab. However, in some cases these characters may be misinterpreted as spaces, causing errors. This may happen in the following situations:

• Input text: If the user enters some text that contains whitespace characters, there may be problems reading this text in Java.
• Copy and Paste: If you copy some text from other applications and paste it into Java, it may contain invisible whitespace characters.
• Database: If you retrieve text from a database, you may encounter similar problems.

Therefore, when processing strings, we must be careful to ensure that whitespace characters are not misinterpreted as spaces.

Next, let’s learn how to deal with this error. One workaround is to use the trim() method to remove leading and trailing whitespace characters from the string as follows:

String str = "   Hello World  ";
str = str.trim();

This will remove the leading and trailing whitespace characters and return a new string with the value "Hello World". However, this method cannot remove spaces in the middle of the string.

Another workaround is to use the replaceAll() method to replace whitespace characters in the string with standard spaces. For example:

String str = "Hello    World";
str = str.replaceAll("\s"," ");

This will replace tab characters with spaces, resulting in a new string "Hello World".

Additionally, if you are writing an application, consider validating user input to ensure that no whitespace characters are misinterpreted as spaces. You can use a regular expression to validate the input like this:

String str = "Hello    World";
if(str.matches("\A\p{ASCII}*\z")){
    //字符串中没有空白字符
}else{
    //字符串中包含空白字符
}

This will ensure that there are no invisible whitespace characters in the string.

In addition to these error handling methods, we can also take some measures to avoid this error from happening. First, we should use appropriate methods to process strings instead of manipulating them manually. Second, we should avoid copying and pasting text directly from user input or other applications. Instead, we should use controls such as file uploads or data entry windows to collect input. Finally, we should always check text retrieved from a database or other source to make sure there are no invisible whitespace characters in it.

In short, in Java programming, whitespace errors in strings may cause some trouble. However, by using the above-mentioned workarounds and avoidance measures, we can easily handle these errors and ensure that our programs run properly.

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