import java.text.DecimalFormat;import java.text.NumberFormat;import java.text.SimpleDateFormat;import java.util.Calendar;public class CalSn {    private static final String LL = "Decompiling this copyrighted software is a violation of both your license agreement and the Digital Millenium Copyright Act of 1998 (http://www.loc.gov/copyright/legislation/dmca.pdf). Under section 1204 of the DMCA, penalties range up to a $500,000 fine or up to five years imprisonment for a first offense. Think about it; pay for a license, avoid prosecution, and feel better about yourself.";    public String getSerial(String userId, String type) {        NumberFormat nf = new DecimalFormat("000");        Calendar cal = Calendar.getInstance();        cal.add(Calendar.YEAR, 3);        cal.add(Calendar.DAY_OF_YEAR, -1);        String licenseNum = nf.format((int) (Math.random() * 1000));        String expTime = new StringBuilder("-")                .append(new SimpleDateFormat("yyMMdd").format(cal.getTime()))                .append("0").toString();        String need = new StringBuilder(userId.substring(0, 1)).append("Y")                .append(type).append("-100").append(licenseNum).append(expTime)                .toString();        String dx = new StringBuilder(need).append(LL).append(userId)                .toString();        int suf = this.decode(dx);        String code = new StringBuilder(need).append(String.valueOf(suf))                .toString();        return this.change(code);    }    private int decode(String s) {        int i;        char[] ac;        int j;        int k;        i = 0;        ac = s.toCharArray();        j = 0;        k = ac.length;        while (j < k) {            i = (31 * i) + ac[j];            j++;        }        return Math.abs(i);    }    private String change(String s) {        byte[] abyte0;        char[] ac;        int i;        int k;        int j;        abyte0 = s.getBytes();        ac = new char[s.length()];        i = 0;        k = abyte0.length;        while (i < k) {            j = abyte0[i];            if ((j >= 48) && (j <= 57)) {                j = (((j - 48) + 5) % 10) + 48;            } else if ((j >= 65) && (j <= 90)) {                j = (((j - 65) + 13) % 26) + 65;            } else if ((j >= 97) && (j <= 122)) {                j = (((j - 97) + 13) % 26) + 97;            }            ac[i] = (char) j;            i++;        }        return String.valueOf(ac);    }    public static void main(String[] args) {        String userId = "qiang";        CalSn myeclipsegen = new CalSn();        String res = myeclipsegen.getSerial(userId, "E3MS");        System.out.println("Serial:" + res);    }}

运行结果：

运行结果：
运行:D:\Java\jdk1.8.0\bin\java.exe CalSn
Serial:dLR8ZF-655880-6151685350542957
输出结束,返回值是[0].

所以序列号为：
qiang
dLR8ZF-655880-6151685350542957