perl 将数段重复的字符串置换为数段不重复的随机字符串

给你个例子
import java.math.BigDecimal;

public class $ {

public static void main(String... _) {
System.out.println(isNum("a"));
System.out.println(isNum("1"));
System.out.println(isNum("1234567890"));
System.out.println(isNum("1.0"));
System.out.println(isNum("1.a"));
}

public static boolean isNum(String str) {

try {
new BigDecimal(str);
return true;
} catch (Exception e) {
return false;
}
}
}