一个简略的验证码生成策略:
public static String code(String tele){
        String []zero={"000000","00000","0000","000","00","0",""};
        int hash = tele.hashCode();
        int number= 2002340;
        long result = hash ^ number;
        long time = System.currentTimeMillis();
        result = time ^ result;
        long code = result % 1000000;
        code= code<0? -code:code;
        int len =((code + "").length());
        return zero[len]+code;
    }
	
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