import java.util.Random;
public class IntegerTest {
/**
* 随机 产生 字符串
*
* @param length
* 字符串的长度
* @return
*/
public static String createCode(int length) {
Random rd = new Random();
String code = "";
int iCode = 0;
int countNum = 0;
for (int i = 0; i < length; i++) {
iCode = rd.nextInt(122);
if ((iCode >= 65 && iCode <= 90) || (iCode >= 97 && iCode <= 122)) { //任意大小写字母
code += (char) iCode;
} else if (iCode >= 0 && iCode <= 9) {
countNum++;
if (countNum > 4)
i--;
else
code += iCode;
}
else
i--;
}
return code;
}
public static void main(String[] args) {
System.out.println(createCode(3));
}
}