用Java存储大量数据

Question

I'd like to store a long integer in Java, specifically the 6144-bit MODP Group (Group 17) from RFC 3526. However this number does not seem to fit to a BigInteger. Is there a way to use this prime number in Java?

EDIT: I tried

BigInteger p = new BigInteger(Integer.toString(pValue));
p = 33751521821438561184518523159967412330064897805741846548173890474429429901326672445203235101919165483964194359460994881062089387893762814044257438204432573941083014827006090258925875161018096327732335800595831915976014208822304007327848132734933297885803213675261564962603340457220776826322500058091310967253976619973988033663666385188155212656268079501726223369693427999804134467810120772356498596945532366527400517575471969335854905274504119509592366013711954148258884879224599915203456315881034776553083676995718335598586395591169999570824515035017543533352697525287753332500527176569576894926734950469293596134095086603716860086302051544539652689091299099784588919052383463057789440565460681441902442399956419060521629604697347879024654313800186078316526964529288062740879011035175920059192178561473199006205896719435014765345518490882366607110905303449152556221163232127426440691921134648766635695850239231304591744215610985029636895406718880766308249227315984267542266259489684372223916445411015900506239419267909716320331208988978180868987431623710347617992356201449023892203230133009421463914291201346063125219636964261683591541014344239275340735690997732222069758773963390876360546515755280517042160525487302898122311669799679447530453600399342697032714458549591285939453949034981248114322322367238645042515984447890788917823576330019151696568654314153058547592091366014550143819685170068343700104677609041166369760080933413605498962382077778845599834907475953430787446201384567328530675275792962354883770806900827183685718353469574731680520621944540947734619035177180057973022652571032196598229259194875709994709721793154158686515748507274224181316948797104601068212015232921691482496346854413698719750190601102705274481050543239815130686073601076304512284549218459846046082253596762433827419060089029417044871218316020923109988915707117567;

Answer 1

That number will easily fit into a Java BigInteger , but both methods you're using to get it are using an intermediate form into which it cannot fit:

BigInteger p = new BigInteger(Integer.toString(pValue));
p = 337515218214385611845185231599674123300648978057418465481...7117567;

The former won't work because the Integer class cannot hold a number that big. The latter won't work because a "naked" number in your source code is treated as an int .

With the actual hex value taken from RFC3526 , the following program shows how to do it:

import java.math.BigInteger;

public class Test
{
    public static void main(String[] args) {
        BigInteger num = new BigInteger(
            "FFFFFFFFFFFFFFFFC90FDAA22168C234C4C6628B80DC1CD129024E08" +
            "8A67CC74020BBEA63B139B22514A08798E3404DDEF9519B3CD3A431B" +
            "302B0A6DF25F14374FE1356D6D51C245E485B576625E7EC6F44C42E9" +
            "A637ED6B0BFF5CB6F406B7EDEE386BFB5A899FA5AE9F24117C4B1FE6" +
            "49286651ECE45B3DC2007CB8A163BF0598DA48361C55D39A69163FA8" +
            "FD24CF5F83655D23DCA3AD961C62F356208552BB9ED529077096966D" +
            "670C354E4ABC9804F1746C08CA18217C32905E462E36CE3BE39E772C" +
            "180E86039B2783A2EC07A28FB5C55DF06F4C52C9DE2BCBF695581718" +
            "3995497CEA956AE515D2261898FA051015728E5A8AAAC42DAD33170D" +
            "04507A33A85521ABDF1CBA64ECFB850458DBEF0A8AEA71575D060C7D" +
            "B3970F85A6E1E4C7ABF5AE8CDB0933D71E8C94E04A25619DCEE3D226" +
            "1AD2EE6BF12FFA06D98A0864D87602733EC86A64521F2B18177B200C" +
            "BBE117577A615D6C770988C0BAD946E208E24FA074E5AB3143DB5BFC" +
            "E0FD108E4B82D120A92108011A723C12A787E6D788719A10BDBA5B26" +
            "99C327186AF4E23C1A946834B6150BDA2583E9CA2AD44CE8DBBBC2DB" +
            "04DE8EF92E8EFC141FBECAA6287C59474E6BC05D99B2964FA090C3A2" +
            "233BA186515BE7ED1F612970CEE2D7AFB81BDD762170481CD0069127" +
            "D5B05AA993B4EA988D8FDDC186FFB7DC90A6C08F4DF435C934028492" +
            "36C3FAB4D27C7026C1D4DCB2602646DEC9751E763DBA37BDF8FF9406" +
            "AD9E530EE5DB382F413001AEB06A53ED9027D831179727B0865A8918" +
            "DA3EDBEBCF9B14ED44CE6CBACED4BB1BDB7F1447E6CC254B33205151" +
            "2BD7AF426FB8F401378CD2BF5983CA01C64B92ECF032EA15D1721D03" +
            "F482D7CE6E74FEF6D55E702F46980C82B5A84031900B1C9E59E7C97F" +
            "BEC7E8F323A97A7E36CC88BE0F1D45B7FF585AC54BD407B22B4154AA" +
            "CC8F6D7EBF48E1D814CC5ED20F8037E0A79715EEF29BE32806A1D58B" +
            "B7C5DA76F550AA3D8A1FBFF0EB19CCB1A313D55CDA56C9EC2EF29632" +
            "387FE8D76E3C0468043E8F663F4860EE12BF2D5B0B7474D6E694F91E" +
            "6DCC4024FFFFFFFFFFFFFFFF", 16);
        System.out.println(num);
    }
}

The output of that program is:

33751521821438561184518523159...8915707117567

Answer 2

Use the BigInteger(String val) constructor to create the number, that is: pass the number as a String . The BigInteger class implements an arbitrary-precision integer data type, any integer can fit - as long as there's enough physical memory to represent it:

BigInteger p = new BigInteger("33751521821438561184518523159967412330064897805741846548173890474429429901326672445203235101919165483964194359460994881062089387893762814044257438204432573941083014827006090258925875161018096327732335800595831915976014208822304007327848132734933297885803213675261564962603340457220776826322500058091310967253976619973988033663666385188155212656268079501726223369693427999804134467810120772356498596945532366527400517575471969335854905274504119509592366013711954148258884879224599915203456315881034776553083676995718335598586395591169999570824515035017543533352697525287753332500527176569576894926734950469293596134095086603716860086302051544539652689091299099784588919052383463057789440565460681441902442399956419060521629604697347879024654313800186078316526964529288062740879011035175920059192178561473199006205896719435014765345518490882366607110905303449152556221163232127426440691921134648766635695850239231304591744215610985029636895406718880766308249227315984267542266259489684372223916445411015900506239419267909716320331208988978180868987431623710347617992356201449023892203230133009421463914291201346063125219636964261683591541014344239275340735690997732222069758773963390876360546515755280517042160525487302898122311669799679447530453600399342697032714458549591285939453949034981248114322322367238645042515984447890788917823576330019151696568654314153058547592091366014550143819685170068343700104677609041166369760080933413605498962382077778845599834907475953430787446201384567328530675275792962354883770806900827183685718353469574731680520621944540947734619035177180057973022652571032196598229259194875709994709721793154158686515748507274224181316948797104601068212015232921691482496346854413698719750190601102705274481050543239815130686073601076304512284549218459846046082253596762433827419060089029417044871218316020923109988915707117567");