Sum of Integers from a random string

Today I was given this interview question. Can someone please help me with the solutions?

/**
 * Return the sum of all integers from a random string. Continuous Integers must be considered as one number. 
 * Given the following inputs, we expect the corresponding output:
 * 
 * "1a2b3c"  ==>6 (1+2+3)
 * "123ab!45c" ==> 168 (123+45)
 * "abcdef" ==> 0 (no integers in String)
 * "0123.4" ==> 127 (0123+4)
 * "dFD$#23++++12@#T1234;/..10" => 1279 (23+12+1234+10)
 * "12a-10b" => 2 (12-10)
 */

private static long SumOfNumbers (String str){
    return null;