Java String contain a substring

Introduction

Checks if String contains a search String, handling null.

This method uses String#indexOf(String). 

contains(null, *)     = false
contains(*, null)     = false
contains("", "")      = true
contains("abc", "")   = true
contains("abc", "a")  = true
contains("abc", "z")  = false

public class Main {
  public static void main(String[] argv) throws Exception {
    String str = "demo2s.com";
    String searchChar = "a";
    System.out.println(contains(str, searchChar));
  }//from  w w  w  . j a  v a2 s .  c o  m
  public static boolean contains(String str, String searchStr) {
     if (str == null || searchStr == null) {
       return false;
     }
     return str.indexOf(searchStr) >= 0;
   }
  public static boolean isEmpty(String str) {
    return str == null || str.length() == 0;
  }
}



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