I want to replace the following string with Blank String ("") if it is equal to “NULL”,“null”, “Null”, “nuLl”, “(null)”, “[null]”, {null} etc. I am finding it difficult to cater all the scenarios with the below regex
^NULL$
So if the input is “a null b” the output will be “a null b”
But if the input is “null” output will be “”
You can truy with this pattern: (?i)[(\\[{]?null[)\\]}]?.
Please, see below example:
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import org.apache.commons.lang3.StringUtils;
public class EnumProgram {
public static void main(String... args) {
test("a NULL b", "a b");
test("a null b", "a b");
test("a Null b", "a b");
test("a NuLl b", "a b");
test("a (null) b", "a b");
test("a [null] b", "a b");
test("a {null} b", "a b");
}
private static void test(String value, String expected) {
String newValue = Util.removeNullString(value);
System.out.println(value + " : " + newValue.equals(expected));
}
}
class Util {
private static Pattern pattern = Pattern.compile("(?i)[(\\[{]?null[)\\]}]?");
public static String removeNullString(String value) {
if (StringUtils.isEmpty(value)) {
return StringUtils.EMPTY;
}
Matcher matcher = pattern.matcher(value);
return matcher.replaceAll(StringUtils.EMPTY);
}
}
What you describe is called a "case-insensitive" regular expression. Not being a Java expert, I found this SO answer which has the following line, edited to fit your needs:
System.out.print(sample.replaceAll("(?i)\\b(?:null)\\b",""));
(null), [null] and {null}?
Use (?i) to validate case insensitive in regular expression. See the below code for example. The below code will output "a b"
String str = "a NULl b";
String regx = "(?i)null";
String str2 = str.replaceAll(regx, "");
System.out.println(str2);
output : a b
Try this:
str.replaceAll("(?i)\\(null\\)|\\[null\\]|\\{null\\}|null", "");
[null), though I don't believe it should.
Try this,
private static String removeNull(String input)
{
String[] splittedValue = input.split(" ");
StringBuilder stringBuilder = new StringBuilder();
for (String value : splittedValue)
{
if (!value.equalsIgnoreCase("null"))
{
stringBuilder.append(value);
stringBuilder.append(" ");
}
}
return stringBuilder.toString();
}
blabla {null} bla?(null), [null] and {null}?
a null b? I would expectab.