@Test

public void test1(){

Random ran = new Random();

char ch[] = new char[]{‘a’,’b’,’c’,’d’,’e’,’f’,’g’,’@’,’1′,’2′,’3′,’4′,’5′};

StringBuilder str = new StringBuilder(“”);

for(int i=0;i<4;i++){

str. append (ch[ran.nextInt(ch.length)]);

}

System.out.println(“验证码=”+str);

}