Java split string line by line

Java split String by new line Example

Java split String by new line example shows how to split string by new line in Java using regular expression as well as ignore empty lines. Example also covers files created in Windows, Unix and Mac OS.

How to split String by a new line in Java?

While processing a file or processing text area inputs you need to split string by new line characters to get each line. You can do this by using regular expressions in Java.

Different operating systems use different characters to represent a new line as given below.

While splitting a string by a new line, we need to take care of all the possible new line characters given above. So basically, we need to look for zero or one \r followed by \n or just \r. Converting it to regex pattern will become “\\r?\\n|\\r” where,

The above pattern will cover all three OS newline characters.

How to include empty trailing lines?

The above pattern ignores the empty trailing line at the end of the string or file.

The last empty line is not included in the output. You can include the trailing empty lines by using a limit parameter in the split method as given below.

How to ignore empty lines in between?

Sometimes string or file contains empty lines between the content as given below.

There are two empty lines between Line1 and Line 2. If you want to ignore empty line between lines, you can use the «[\r?\n|\r]+» regex pattern where,

Our pattern will match one or more newlines since we applied “+” to the character group.

Note: We do not need to escape \r or \n because they are inside the character group ([]).

How to split string by new line in Java 8?

If you are using Java 8, you can use «\R» pattern instead of «\\r?\\n|\\r» pattern. The «\R» pattern covers all the new line characters.

How to split string by new line using line.separator? (Not recommended)

The line.separator is a system property that gives default newline characters for the operating system. It can be used to split the string as given below.

Why it is not recommended? In the above example, the string contains \r\n as a new line and the output was generated in the Windows machine. So, when we get “line.separator” property, it returned Windows new line which is \r\n and program worked as expected.

If the same code was ran on Unix, “line.separator” would have returned \n and our code would have failed. This approach is not recommended for the same reason, it is platform dependent. Means you will not be able to process file generated in a different environment.

You can also split string by dot, pipe, and comma or you can split string in equal lengths as well.

Please let me know your views in the comments section below.

About the author

I have a master’s degree in computer science and over 18 years of experience designing and developing Java applications. I have worked with many fortune 500 companies as an eCommerce Architect. Follow me on LinkedIn and Facebook.

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Splitting Java Strings by Line: A Complete Guide with Examples

Learn how to split a Java string by line using different methods, including System.getProperty(), StringUtils split(), and lines() method in Java 11. Get helpful tips and best practices for text processing.

• The Importance of Splitting a Java String by Line
• Using System.getProperty(«line.separator») Method
• StringUtils split() Method
• Using split() Method with Regular Expression
• The lines() Method in Java 11
• Splitting a String While Keeping Delimiters
• Other helpful code examples for splitting Java strings by line
• Conclusion
• How to split a string into lines Java?
• How to break a line in Java?
• How to split a string by comma and new line in Java?
• What does line split mean in Java?

As a software developer, you may have come across situations where you need to split a Java string by line. Whether it’s for file processing or data manipulation, splitting a string by line is a fundamental task in text processing. Fortunately, Java’s split() method makes this task easy and straightforward. In this guide, we will explore different methods for splitting a Java string by line, including using the System.getProperty() method, StringUtils split() method, and the lines() method introduced in Java 11.

The Importance of Splitting a Java String by Line

Before diving into the different methods of splitting a Java string by line, let’s understand why this task is important. In Java, a string is a sequence of characters, and each line in a string is separated by a line separator. A line separator is a special character that represents the end of a line, and it varies depending on the operating system. For example, on Unix-based systems, a line separator is represented as ‘\n’, while on Windows-based systems, it is represented as ‘\r\n’.

Splitting a Java string by line allows you to perform various operations on each line of the string separately. For instance, you may want to process each line of a file separately or extract specific information from each line. By splitting a string into lines, you can perform these operations more efficiently and accurately.

Using System.getProperty(«line.separator») Method

The System.getProperty() method can be used to retrieve the line separator for the current operating system. We can use this method to split a Java string by line by passing the line separator as a delimiter to the split() method.

Here’s an example of how to split a Java string by line using the System.getProperty() method:

String str = "This is a\nsample string\nwith multiple lines."; String[] lines = str.split(System.getProperty("line.separator"));for (String line : lines)

This is a sample string with multiple lines. 

As you can see, we have successfully split the string into lines using the line separator retrieved by the System.getProperty() method.

StringUtils split() Method

The StringUtils split() method from the org.apache.commons.lang package provides a simpler and more flexible way to split a string by line. We can use the split() method with the line separator as a delimiter to split a Java string by line.

Here’s an example of how to split a Java string by line using the StringUtils split() method:

import org.apache.commons.lang.StringUtils;String str = "This is a\nsample string\nwith multiple lines."; String[] lines = StringUtils.split(str, System.getProperty("line.separator"));for (String line : lines)

This is a sample string with multiple lines. 

As you can see, the StringUtils split() method provides a cleaner and more concise way to split a string by line.

Using split() Method with Regular Expression

The split() method can also be used to split a Java string by line using a regular expression. We can use the regular expression “\r?\n” to split a string by line, which covers different line separators across different operating systems.

Here’s an example of how to split a Java string by line using a regular expression:

String str = "This is a\nsample string\r\nwith multiple lines."; String[] lines = str.split("\r?\n");for (String line : lines)

This is a sample string with multiple lines. 

As you can see, the regular expression “\r?\n” matches both ‘\n’ and ‘\r\n’ line separators, allowing us to split the string by line correctly.

The lines() Method in Java 11

The lines() method introduced in Java 11 allows us to split a Java string into lines without using a delimiter explicitly. This method returns a Stream of lines, which can be converted into an array or List of strings.

Here’s an example of how to split a Java string by line using the lines() method:

String str = "This is a\nsample string\nwith multiple lines."; String[] lines = str.lines().toArray(String[]::new);for (String line : lines)

This is a sample string with multiple lines. 

As you can see, the lines() method provides a more elegant and concise way to split a string by line in Java 11.

Splitting a String While Keeping Delimiters

Sometimes we may need to split a Java string while keeping the delimiters. We can achieve this by using capturing groups in the regular expression, which include the delimiter in the resulting substrings.

Here’s an example of how to split a Java string while keeping the delimiters:

String str = "This is a\nsample string\r\nwith multiple lines."; String[] lines = str.split("(\r?\n)");for (String line : lines)

This is asample stringwith multiple lines. 

As you can see, the capturing group in the regular expression includes the line separator in the resulting substrings.

Other helpful code examples for splitting Java strings by line

In Java , for example, split on . in java code sample

String textfile = "ReadMe.txt"; String filename = textfile.split("\\.")[0]; String extension = textfile.split("\\.")[1];

In Java as proof, split in java code sample

String text = "Int--String"; String[] parts = text.split("--"); String part0 = parts[0];//"Int" String part1 = parts[1];//"String" System.out.println(part0/*"Int"*/ + " is a datatype for a number and a " + part1/*"String"*/ + " is a datatype for a text.");// Output: Int is a datatype for a number and a String is a datatype for a text.

In Java case in point, java split on < code example

Conclusion

Splitting a Java string by line is a common task in text processing, and there are multiple ways to accomplish it using the split() method. Using the System.getProperty() method, StringUtils split() method, regular expression , and lines() method in Java 11 are all viable options depending on the situation. By understanding these methods and best practices, you can efficiently split Java strings by line in your projects.

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Java split string line by line

если не хотите экранировать или не знаете, надо ли, просто пишите text.split(Pattern.quote(«<нужный знак>«)); Тогда значение всегда будет строковым и не касаться регулярок. Ну и если нет автоимпорта, то не забудьте импортировать java.util.regex.Pattern

Статья класс, можно добавить, что в качестве параметра split принимает и сразу несколько разделителей

 String str = "Амо/ре.амо,ре"; String[] words = str.split("[/\\.,]"); // Амо ре амо ре 

А если нет разделителей, но есть сплошная строка длиной N символов, и нужно разделить ее, допустим, на число M ? То как в этом случае быть?

Когда я в первый раз прочитал данную статью, ничего не понял и посчитал данную статью бесполезной. А на тот момент я изучал первый месяц. И сейчас, спустя еще 2 месяца я наконец то понял что тут написано) И могу теперь смело сказать что да, статья полезная.

А если в задаче разделитель вводится с клавиатуры, то как добавить\\ чтоб ошибки зарезервированного знака не было?

По-моему, зря ничего не сказано про то, что точка ( «.») не может служить разделителем, в отличие от запятой например. И её надо обозначать слэшами — («\\.»)

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How to split String by newline in java

In this post, we will see how to split String by newline in java.

Splitting a string by a newline character is one of the most common string operations performed in java, broadly there are two ways of achieving this task as mentioned below.

While considering new line characters, it is important to understand that the character differs based on the operating system, and the regular expression must be formed in such a way that it covers new line characters for all the operating systems, so that the code is not platform dependent.

Let’s now take a look at different operating systems and their corresponding new line characters.

Next, let’s start looking in detail at each method mentioned earlier in detail.

Split by new line character using regular expressions and split() method

As already discussed splitting the string by newline required us to consider the newline characters of the different operating systems so as to provide a generic platform-independent solution for the problem, This requires us to form a regex that will be zero or 1 combination of \r followed by \r or just \r based on the operating system we are considering.

Taking the above into consideration out regex will be “\r?\n|\r”.
Next, let’s try to understand this regex by understanding each of its parts.

Note, here we are using \\ as single \ is an escape character.

Let’s see a code example for this.

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