Find difference between two Strings

Question

Suppose I have two long strings. They are almost same.

String a = "this is a example" String b = "this is a examp" 

Above code is just for example. Actual strings are quite long.

Problem is one string have 2 more characters than the other.

How can I check which are those two character?

Answer 1

You can use StringUtils.difference(String first, String second).

This is how they implemented it:

public static String difference(String str1, String str2) {     if (str1 == null) {         return str2;     }     if (str2 == null) {         return str1;     }     int at = indexOfDifference(str1, str2);     if (at == INDEX_NOT_FOUND) {         return EMPTY;     }     return str2.substring(at); }  public static int indexOfDifference(CharSequence cs1, CharSequence cs2) {     if (cs1 == cs2) {         return INDEX_NOT_FOUND;     }     if (cs1 == null || cs2 == null) {         return 0;     }     int i;     for (i = 0; i < cs1.length() && i < cs2.length(); ++i) {         if (cs1.charAt(i) != cs2.charAt(i)) {             break;         }     }     if (i < cs2.length() || i < cs1.length()) {         return i;     }     return INDEX_NOT_FOUND; } 

Answer 2

To find the difference between 2 Strings you can use the StringUtils class and the difference method. It compares the two Strings, and returns the portion where they differ.

 StringUtils.difference(null, null) = null  StringUtils.difference("", "") = ""  StringUtils.difference("", "abc") = "abc"  StringUtils.difference("abc", "") = ""  StringUtils.difference("abc", "abc") = ""  StringUtils.difference("ab", "abxyz") = "xyz"  StringUtils.difference("abcde", "abxyz") = "xyz"  StringUtils.difference("abcde", "xyz") = "xyz"