# Java String Split: Use String.split() With Regex

> Split a string in Java using the String.split() method, which accepts a regex delimiter, requires escaping special characters, and handles edge case inputs

**URL:** https://sentry.io/answers/how-to-split-a-string-in-java/

---

## The Problem

How do I split a String in Java?

## The Solution

The easiest way to split a string in Java is to use the `String.split()` method.

```java
public class Main {

    public static void main(String[] arg) {
        String str = "how:to:split:a:string:in:java";
        String[] arrOfStr = str.split(":");
        for (String a : arrOfStr) {
            System.out.println(a);
        }
    }
}
```

Output:

```
how
to
split
a
string
in
java
```

In the example above, we use `:` as the delimiter, but note that the parameter the `split()` method takes is a regular expression. This means it is easy to do things like split on one or more `:` characters by using `:+`.

```java
public class Main {

    public static void main(String[] arg) {
        String str = "how:to::split:::a:string:in:java";
        String[] arrOfStr = str.split(":+");
        for (String a : arrOfStr) {
            System.out.println(a);
        }
    }
}
```

The output of this example will be the same as the output of the previous example, as the regex ignores the additional colons.

This means that if you want to split a string on a character that has special meaning in regular expressions, you need to escape it. For example, to split a string on a period (`.`), use `str.split("\\.")`.

```java
public class Main {

    public static void main(String[] arg) {
        String str = "how.to.split.a.string.in.java";
        String[] arrOfStr = str.split("\\.");
        for (String a : arrOfStr) {
            System.out.println(a);
        }
    }
}
```

This example also has the same output as the previous examples.

### Edge cases in Java String Splitting

If the split character is not present in the target string, the output will be an array with one element containing the entire string.

```java
public class Main {

    public static void main(String[] arg) {
        String str = "how.to.split.a.string.in.java";
        String[] arrOfStr = str.split("z");
        for (String a : arrOfStr) {
            System.out.println(a);
        }
    }
}
```

Output:

```
how.to.split.a.string.in.java
```

If the string consists of only the split character, the output will be an empty array.

```java
public class Main {

    public static void main(String[] arg) {
        String str = "::::";
        String[] arrOfStr = str.split(":");
        System.out.println(arrOfStr.length);
    }
}
```

Output:

```
0
```

Similarly, if you split an array on everything, the output will be nothing.

```java
public class Main {

    public static void main(String[] arg) {
        String str = "java";
        String[] arrOfStr = str.split(".");
        System.out.println(arrOfStr.length);
    }
}
```

Output:

```
0
```

If you split an array on nothing, the output will be everything.

```java
public class Main {

    public static void main(String[] arg) {
        String str = "java";
        String[] arrOfStr = str.split("");
        for (String a : arrOfStr) {
            System.out.println(a);
        }
    }
}
```

Output

```
j
a
v
a
```

---

*Source: [sentry.io/answers/how-to-split-a-string-in-java/](https://sentry.io/answers/how-to-split-a-string-in-java/)*