Java randomly generated string tool class

 PackageAA;Importjava.util.ArrayList;Importjava.util.Arrays;ImportJava.util.Random;/*** Character randomly generated class*/ Public classRandomdemo {/*** Randomly generated type enumeration*/     Public Static enumTYPE {/**Small character Type*/Letter ,/**Uppercase Character type*/Capital ,/**Digital Type*/Number ,/**Large + small character type*/Letter_capital,/**Small character + digital type*/Letter_number,/**uppercase characters + numbers*/Capital_number,/**Large + small character + digital type*/Letter_capital_number,}Private Staticstring[] lowercase = {"A", "B", "C", "D", "E", "F", "G", "H", "I", "J", "K", "L", "M", "N", "O",            "P", "Q", "R", "s", "T", "U", "V", "w", "X", "Y", "Z" }; Private StaticString[] Capital = {"A", "B", "C", "D", "E", "F", "G", "H", "I", "J", "K", "L", "M", "N", "O", "P",            "Q", "R", "S", "T", "U", "V", "W", "X", "Y", "Z" }; Private Staticstring[] Number = {"1", "2", "3", "4", "5", "6", "7", "8", "9", "0" }; /*** Static random number*/    Private StaticRandom random =NewRandom ();/*** Get Random Combo code *@paramnum Number of digits *@paramtype * @type * <br> lowercase letter, * <br> uppercase Capital, * <br> Digital number, * & lt;br> Large + small character type letter_capital, * <br> characters + digital Letter_number, * <br> big characters + digital Capital_number, * < ;br> Large + small character + digital type Letter_capital_number,*/     Public StaticString Getrandom (intnum, type type) {ArrayList<String> temp =NewArraylist<string>(); StringBuffer Code=NewStringBuffer (); Switch(type) { CaseLETTER:temp.addAll (arrays.aslist (lowercase));  Break;  CaseCAPITAL:temp.addAll (arrays.aslist (capital));  Break;  CaseNUMBER:temp.addAll (arrays.aslist (number));  Break;  CaseLETTER_CAPITAL:temp.addAll (arrays.aslist (lowercase));            Temp.addall (arrays.aslist (capital));  Break;  CaseLETTER_NUMBER:temp.addAll (arrays.aslist (lowercase));            Temp.addall (arrays.aslist (number));  Break;  CaseCAPITAL_NUMBER:temp.addAll (arrays.aslist (capital));            Temp.addall (arrays.aslist (number));  Break;  CaseLETTER_CAPITAL_NUMBER:temp.addAll (arrays.aslist (lowercase));            Temp.addall (arrays.aslist (capital));            Temp.addall (arrays.aslist (number));  Break; }         for(inti = 0; i < num; i++) {code.append (Temp.get (Random.nextint (Temp.size ()))); }        returncode.tostring (); }
Test

  void Main (string[] args) {        System.out.println (Randomdemo.getrandom (Ten, RandomDemo.TYPE.LETTER_CAPITAL) ); }

}

Java randomly generated string tool class