The Apache Commons Lang page says ” The Lang Component provides a host of helper utilities for the java.lang API, notably String manipulation methods, basic numerical methods, object reflection, creation and serialization, and System properties. Additionally it contains an inheritable enum type, an exception structure that supports multiple types of nested-Exceptions, basic enhancements to java.util.Date and a series of utlities dedicated to help with building methods, such as hashCode, toString and equals.”
I have been using the commons library for quite sometime. But everything are in bits and pieces. So, just thought i could learn something more. But before that download the commons lang libraries.
Counting the number of occurences of a String in a particular file or String requires lots of code. Here is one simple solution.
import org.apache.commons.lang.StringUtils;
public class StringMatch {
public static void main(String[] args) {
String inputString=”hello arun, say hello to all coz” +
” it’s going to save you from a hell a lot of trouble”;
int occurences=StringUtils.countMatches(inputString, “hell”);
System.out.println(occurences); //gives you 3
}
}
If you are reading from a file, then go for
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.io.LineNumberReader;
import org.apache.commons.lang.StringUtils;
public class StringFromFile {
public static void main(String[] args) {
try {
FileReader fileReader=new FileReader(”InputFile”);
LineNumberReader lineReader=new LineNumberReader(fileReader);
int count=0;
while (lineReader.ready()){
count=count+StringUtils.countMatches(lineReader.readLine(),
“hell”);
}
System.out.println(”Number of occurences is : “+count);
} catch (FileNotFoundException e) {
e.printStackTrace();
}
catch (IOException e) {
e.printStackTrace();
}
}
}
Download the entire source code
Tags: commons lang, java, string count, string occurences
