用java實現zip壓縮和解壓縮功能。

本文使用了jdk1.5.0_13的源代碼。(java.uti.zip*)

實現方法：首先將java.uti.zip中的源代碼解壓出來。找到DeflaterOutputStream、InflaterInputStream、ZipConstants、ZipEntry、ZipInputStream、ZipOutputStream，放到新的包com.work.util.zip中，重新組織這些文件的import，能使用當前包中類的就使用當前包中的類。

重點要修改的類：ZipEntry，修改內容如下：

1. //修改對應的程序，在這裏加載zip庫
2. static{
3. /*loadtheziplibrary*/
4. java.security.AccessController
5. .doPrivileged(newsun.security.action.LoadLibraryAction("zip"));
6. //initIDs();
7. }
8. //static{
9. ///*ZiplibraryisloadedfromSystem.initializeSystemClass*/
10. //initIDs();
11. //}
13. //privatestaticnativevoidinitIDs();

其次修改ZipInputStream，大約在279行。

1. //ZipEntrye=createZipEntry(getUTF8String(b,0,len));
2. ZipEntrye=null;
3. try{
4. if(this.encoding.toUpperCase().equals("UTF-8"))
5. e=createZipEntry(getUTF8String(b,0,len));
6. else
7. e=createZipEntry(newString(b,0,len,this.encoding));
8. }catch(ExceptionbyteE){
9. e=createZipEntry(getUTF8String(b,0,len));
10. }
11. //增加構造方法
12. private String encoding = "UTF-8";
13. public ZipInputStream(InputStream in, String encoding) {
    super(new PushbackInputStream(in, 512), new Inflater(true), 512);
    usesDefaultInflater = true;
    if (in == null) {
    throw new NullPointerException("in is null");
    }
    this.encoding = encoding;
    }

再次修改ZipOutputStream類，源代碼如下：

1. /*
2. *@(#)ZipOutputStream.java1.3103/12/19
3. *
4. *Copyright2004SunMicrosystems,Inc.Allrightsreserved.
5. *SUNPROPRIETARY/CONFIDENTIAL.Useissubjecttolicenseterms.
6. */
8. packagecom.work.util.zip;
10. importjava.io.IOException;
11. importjava.io.OutputStream;
12. importjava.util.Enumeration;
13. importjava.util.Hashtable;
14. importjava.util.Vector;
15. importjava.util.zip.CRC32;
16. importjava.util.zip.Deflater;
17. importjava.util.zip.ZipException;
19. /**
20. *ThisclassimplementsanoutputstreamfilterforwritingfilesintheZIP
21. *fileformat.Includessupportforbothcompressedanduncompressedentries.
22. *
23. *@authorDavidConnelly
24. *@version1.31,12/19/03
25. */
26. publicclassZipOutputStreamextendsDeflaterOutputStreamimplements
27. ZipConstants{
28. privateZipEntryentry;
29. privateVectorentries=newVector();
30. privateHashtablenames=newHashtable();
31. privateCRC32crc=newCRC32();
32. privatelongwritten=0;
33. privatelonglocoff=0;
34. privateStringcomment;
35. privateintmethod=DEFLATED;
36. privatebooleanfinished;
38. privatebooleanclosed=false;
40. /**
41. *Checktomakesurethatthisstreamhasnotbeenclosed
42. */
43. privatevoidensureOpen()throwsIOException{
44. if(closed){
45. thrownewIOException("Streamclosed");
46. }
47. }
49. /**
50. *Compressionmethodforuncompressed(STORED)entries.
51. */
52. publicstaticfinalintSTORED=ZipEntry.STORED;
54. /**
55. *Compressionmethodforcompressed(DEFLATED)entries.
56. */
57. publicstaticfinalintDEFLATED=ZipEntry.DEFLATED;
59. privateStringencoding="UTF-8";
61. publicZipOutputStream(OutputStreamout,Stringencoding){
62. super(out,newDeflater(Deflater.DEFAULT_COMPRESSION,true));
63. usesDefaultDeflater=true;
64. this.encoding=encoding;
65. }
67. /**
68. *CreatesanewZIPoutputstream.
69. *
70. *@paramout
71. *theactualoutputstream
72. */
73. publicZipOutputStream(OutputStreamout){
74. super(out,newDeflater(Deflater.DEFAULT_COMPRESSION,true));
75. usesDefaultDeflater=true;
76. }
78. /**
79. *SetstheZIPfilecomment.
80. *
81. *@paramcomment
82. *thecommentstring
83. *@exceptionIllegalArgumentException
84. *ifthelengthofthespecifiedZIPfilecommentisgreater
85. *than0xFFFFbytes
86. */
87. publicvoidsetComment(Stringcomment){
88. if(comment!=null&&comment.length()>0xffff/3
89. &&getUTF8Length(comment)>0xffff){
90. thrownewIllegalArgumentException("ZIPfilecommenttoolong.");
91. }
92. this.comment=comment;
93. }
95. /**
96. *Setsthedefaultcompressionmethodforsubsequententries.Thisdefault
97. *willbeusedwheneverthecompressionmethodisnotspecifiedforan
98. *individualZIPfileentry,andisinitiallysettoDEFLATED.
99. *
100. *@parammethod
101. *thedefaultcompressionmethod
102. *@exceptionIllegalArgumentException
103. *ifthespecifiedcompressionmethodisinvalid
104. */
105. publicvoidsetMethod(intmethod){
106. if(method!=DEFLATED&&method!=STORED){
107. thrownewIllegalArgumentException("invalidcompressionmethod");
108. }
109. this.method=method;
110. }
112. /**
113. *SetsthecompressionlevelforsubsequententrieswhichareDEFLATED.The
114. *defaultsettingisDEFAULT_COMPRESSION.
115. *
116. *@paramlevel
117. *thecompressionlevel(0-9)
118. *@exceptionIllegalArgumentException
119. *ifthecompressionlevelisinvalid
120. */
121. publicvoidsetLevel(intlevel){
122. def.setLevel(level);
123. }
125. /**
126. *BeginswritinganewZIPfileentryandpositionsthestreamtothestart
127. *oftheentrydata.Closesthecurrententryifstillactive.Thedefault
128. *compressionmethodwillbeusedifnocompressionmethodwasspecified
129. *fortheentry,andthecurrenttimewillbeusediftheentryhasnoset
130. *modificationtime.
131. *
132. *@parame
133. *theZIPentrytobewritten
134. *@exceptionZipException
135. *ifaZIPformaterrorhasoccurred
136. *@exceptionIOException
137. *ifanI/Oerrorhasoccurred
138. */
139. publicvoidputNextEntry(ZipEntrye)throwsIOException{
140. ensureOpen();
141. if(entry!=null){
142. closeEntry();//closepreviousentry
143. }
144. if(e.time==-1){
145. e.setTime(System.currentTimeMillis());
146. }
147. if(e.method==-1){
148. e.method=method;//usedefaultmethod
149. }
150. switch(e.method){
151. caseDEFLATED:
152. if(e.size==-1||e.csize==-1||e.crc==-1){
153. //storesize,compressedsize,andcrc-32indatadescriptor
154. //immediatelyfollowingthecompressedentrydata
155. e.flag=8;
156. }elseif(e.size!=-1&&e.csize!=-1&&e.crc!=-1){
157. //storesize,compressedsize,andcrc-32inLOCheader
158. e.flag=0;
159. }else{
160. thrownewZipException(
161. "DEFLATEDentrymissingsize,compressedsize,orcrc-32");
162. }
163. e.version=20;
164. break;
165. caseSTORED:
166. //compressedsize,uncompressedsize,andcrc-32mustallbe
167. //setforentriesusingSTOREDcompressionmethod
168. if(e.size==-1){
169. e.size=e.csize;
170. }elseif(e.csize==-1){
171. e.csize=e.size;
172. }elseif(e.size!=e.csize){
173. thrownewZipException(
174. "STOREDentrywherecompressed!=uncompressedsize");
175. }
176. if(e.size==-1||e.crc==-1){
177. thrownewZipException(
178. "STOREDentrymissingsize,compressedsize,orcrc-32");
179. }
180. e.version=10;
181. e.flag=0;
182. break;
183. default:
184. thrownewZipException("unsupportedcompressionmethod");
185. }
186. e.offset=written;
187. if(names.put(e.name,e)!=null){
188. thrownewZipException("duplicateentry:"+e.name);
189. }
190. writeLOC(e);
191. entries.addElement(e);
192. entry=e;
193. }
195. /**
196. *ClosesthecurrentZIPentryandpositionsthestreamforwritingthe
197. *nextentry.
198. *
199. *@exceptionZipException
200. *ifaZIPformaterrorhasoccurred
201. *@exceptionIOException
202. *ifanI/Oerrorhasoccurred
203. */
204. publicvoidcloseEntry()throwsIOException{
205. ensureOpen();
206. ZipEntrye=entry;
207. if(e!=null){
208. switch(e.method){
209. caseDEFLATED:
210. def.finish();
211. while(!def.finished()){
212. deflate();
213. }
214. if((e.flag&8)==0){
215. //verifysize,compressedsize,andcrc-32settings
216. if(e.size!=def.getBytesRead()){
217. thrownewZipException("invalidentrysize(expected"
218. +e.size+"butgot"+def.getBytesRead()
219. +"bytes)");
220. }
221. if(e.csize!=def.getBytesWritten()){
222. thrownewZipException(
223. "invalidentrycompressedsize(expected"
224. +e.csize+"butgot"
225. +def.getBytesWritten()+"bytes)");
226. }
227. if(e.crc!=crc.getValue()){
228. thrownewZipException(
229. "invalidentryCRC-32(expected0x"
230. +Long.toHexString(e.crc)
231. +"butgot0x"
232. +Long.toHexString(crc.getValue())
233. +")");
234. }
235. }else{
236. e.size=def.getBytesRead();
237. e.csize=def.getBytesWritten();
238. e.crc=crc.getValue();
239. writeEXT(e);
240. }
241. def.reset();
242. written+=e.csize;
243. break;
244. caseSTORED:
245. //wealreadyknowthatbothe.sizeande.csizearethesame
246. if(e.size!=written-locoff){
247. thrownewZipException("invalidentrysize(expected"
248. +e.size+"butgot"+(written-locoff)
249. +"bytes)");
250. }
251. if(e.crc!=crc.getValue()){
252. thrownewZipException("invalidentrycrc-32(expected0x"
253. +Long.toHexString(e.crc)+"butgot0x"
254. +Long.toHexString(crc.getValue())+")");
255. }
256. break;
257. default:
258. thrownewInternalError("invalidcompressionmethod");
259. }
260. crc.reset();
261. entry=null;
262. }
263. }
265. /**
266. *WritesanarrayofbytestothecurrentZIPentrydata.Thismethodwill
267. *blockuntilallthebytesarewritten.
268. *
269. *@paramb
270. *thedatatobewritten
271. *@paramoff
272. *thestartoffsetinthedata
273. *@paramlen
274. *thenumberofbytesthatarewritten
275. *@exceptionZipException
276. *ifaZIPfileerrorhasoccurred
277. *@exceptionIOException
278. *ifanI/Oerrorhasoccurred
279. */
280. publicsynchronizedvoidwrite(byte[]b,intoff,intlen)
281. throwsIOException{
282. ensureOpen();
283. if(off<0||len<0||off>b.length-len){
284. thrownewIndexOutOfBoundsException();
285. }elseif(len==0){
286. return;
287. }
289. if(entry==null){
290. thrownewZipException("nocurrentZIPentry");
291. }
292. switch(entry.method){
293. caseDEFLATED:
294. super.write(b,off,len);
295. break;
296. caseSTORED:
297. written+=len;
298. if(written-locoff>entry.size){
299. thrownewZipException(
300. "attempttowritepastendofSTOREDentry");
301. }
302. out.write(b,off,len);
303. break;
304. default:
305. thrownewInternalError("invalidcompressionmethod");
306. }
307. crc.update(b,off,len);
308. }
310. /**
311. *FinisheswritingthecontentsoftheZIPoutputstreamwithoutclosing
312. *theunderlyingstream.Usethismethodwhenapplyingmultiplefiltersin
313. *successiontothesameoutputstream.
314. *
315. *@exceptionZipException
316. *ifaZIPfileerrorhasoccurred
317. *@exceptionIOException
318. *ifanI/Oexceptionhasoccurred
319. */
320. publicvoidfinish()throwsIOException{
321. ensureOpen();
322. if(finished){
323. return;
324. }
325. if(entry!=null){
326. closeEntry();
327. }
328. if(entries.size()<1){
329. thrownewZipException("ZIPfilemusthaveatleastoneentry");
330. }
331. //writecentraldirectory
332. longoff=written;
333. Enumeratione=entries.elements();
334. while(e.hasMoreElements()){
335. writeCEN((ZipEntry)e.nextElement());
336. }
337. writeEND(off,written-off);
338. finished=true;
339. }
341. /**
342. *ClosestheZIPoutputstreamaswellasthestreambeingfiltered.
343. *
344. *@exceptionZipException
345. *ifaZIPfileerrorhasoccurred
346. *@exceptionIOException
347. *ifanI/Oerrorhasoccurred
348. */
349. publicvoidclose()throwsIOException{
350. if(!closed){
351. super.close();
352. closed=true;
353. }
354. }
356. /*
357. *Writeslocalfile(LOC)headerforspecifiedentry.
358. */
359. privatevoidwriteLOC(ZipEntrye)throwsIOException{
360. writeInt(LOCSIG);//LOCheadersignature
361. writeShort(e.version);//versionneededtoextract
362. writeShort(e.flag);//generalpurposebitflag
363. writeShort(e.method);//compressionmethod
364. writeInt(e.time);//lastmodificationtime
365. if((e.flag&8)==8){
366. //storesize,uncompressedsize,andcrc-32indatadescriptor
367. //immediatelyfollowingcompressedentrydata
368. writeInt(0);
369. writeInt(0);
370. writeInt(0);
371. }else{
372. writeInt(e.crc);//crc-32
373. writeInt(e.csize);//compressedsize
374. writeInt(e.size);//uncompressedsize
375. }
376. //byte[]nameBytes=getUTF8Bytes(e.name);
377. byte[]nameBytes=null;
378. try{
379. if(this.encoding.toUpperCase().equals("UTF-8"))
380. nameBytes=getUTF8Bytes(e.name);
381. else
382. nameBytes=e.name.getBytes(this.encoding);
383. }catch(ExceptionbyteE){
384. nameBytes=getUTF8Bytes(e.name);
385. }
387. writeShort(nameBytes.length);
388. writeShort(e.extra!=null?e.extra.length:0);
389. writeBytes(nameBytes,0,nameBytes.length);
390. if(e.extra!=null){
391. writeBytes(e.extra,0,e.extra.length);
392. }
393. locoff=written;
394. }
396. /*
397. *Writesextradatadescriptor(EXT)forspecifiedentry.
398. */
399. privatevoidwriteEXT(ZipEntrye)throwsIOException{
400. writeInt(EXTSIG);//EXTheadersignature
401. writeInt(e.crc);//crc-32
402. writeInt(e.csize);//compressedsize
403. writeInt(e.size);//uncompressedsize
404. }
406. /*
407. *Writecentraldirectory(CEN)headerforspecifiedentry.REMIND:add
408. *supportforfileattributes
409. */
410. privatevoidwriteCEN(ZipEntrye)throwsIOException{
411. writeInt(CENSIG);//CENheadersignature
412. writeShort(e.version);//versionmadeby
413. writeShort(e.version);//versionneededtoextract
414. writeShort(e.flag);//generalpurposebitflag
415. writeShort(e.method);//compressionmethod
416. writeInt(e.time);//lastmodificationtime
417. writeInt(e.crc);//crc-32
418. writeInt(e.csize);//compressedsize
419. writeInt(e.size);//uncompressedsize
420. //byte[]nameBytes=getUTF8Bytes(e.name);
421. byte[]nameBytes=null;
422. try{
423. if(this.encoding.toUpperCase().equals("UTF-8"))
424. nameBytes=getUTF8Bytes(e.name);
425. else
426. nameBytes=e.name.getBytes(this.encoding);
427. }catch(ExceptionbyteE){
428. nameBytes=getUTF8Bytes(e.name);
429. }
430. writeShort(nameBytes.length);
431. writeShort(e.extra!=null?e.extra.length:0);
432. byte[]commentBytes;
433. if(e.comment!=null){
435. //commentBytes=getUTF8Bytes(e.comment);
437. try{
438. if(this.encoding.toUpperCase().equals("UTF-8"))
439. commentBytes=getUTF8Bytes(e.comment);
440. else
441. commentBytes=e.comment.getBytes(this.encoding);
442. }catch(ExceptionbyteE){
443. commentBytes=getUTF8Bytes(e.comment);
444. }
446. writeShort(commentBytes.length);
447. }else{
448. commentBytes=null;
449. writeShort(0);
450. }
451. writeShort(0);//startingdisknumber
452. writeShort(0);//internalfileattributes(unused)
453. writeInt(0);//externalfileattributes(unused)
454. writeInt(e.offset);//relativeoffsetoflocalheader
455. writeBytes(nameBytes,0,nameBytes.length);
456. if(e.extra!=null){
457. writeBytes(e.extra,0,e.extra.length);
458. }
459. if(commentBytes!=null){
460. writeBytes(commentBytes,0,commentBytes.length);
461. }
462. }
464. /*
465. *Writesendofcentraldirectory(END)header.
466. */
467. privatevoidwriteEND(longoff,longlen)throwsIOException{
468. writeInt(ENDSIG);//ENDrecordsignature
469. writeShort(0);//numberofthisdisk
470. writeShort(0);//centraldirectorystartdisk
471. writeShort(entries.size());//numberofdirectoryentriesondisk
472. writeShort(entries.size());//totalnumberofdirectoryentries
473. writeInt(len);//lengthofcentraldirectory
474. writeInt(off);//offsetofcentraldirectory
475. if(comment!=null){//zipfilecomment
476. //byte[]b=getUTF8Bytes(comment);
477. byte[]b=null;
479. try{
480. if(this.encoding.toUpperCase().equals("UTF-8"))
481. b=getUTF8Bytes(comment);
482. else
483. b=comment.getBytes(this.encoding);
484. }catch(ExceptionbyteE){
485. b=getUTF8Bytes(comment);
486. }
487. writeShort(b.length);
488. writeBytes(b,0,b.length);
489. }else{
490. writeShort(0);
491. }
492. }
494. /*
495. *Writesa16-bitshorttotheoutputstreaminlittle-endianbyteorder.
496. */
497. privatevoidwriteShort(intv)throwsIOException{
498. OutputStreamout=this.out;
499. out.write((v>>>0)&0xff);
500. out.write((v>>>8)&0xff);
501. written+=2;
502. }
504. /*
505. *Writesa32-bitinttotheoutputstreaminlittle-endianbyteorder.
506. */
507. privatevoidwriteInt(longv)throwsIOException{
508. OutputStreamout=this.out;
509. out.write((int)((v>>>0)&0xff));
510. out.write((int)((v>>>8)&0xff));
511. out.write((int)((v>>>16)&0xff));
512. out.write((int)((v>>>24)&0xff));
513. written+=4;
514. }
516. /*
517. *Writesanarrayofbytestotheoutputstream.
518. */
519. privatevoidwriteBytes(byte[]b,intoff,intlen)throwsIOException{
520. super.out.write(b,off,len);
521. written+=len;
522. }
524. /*
525. *ReturnsthelengthofString'sUTF8encoding.
526. */
527. staticintgetUTF8Length(Strings){
528. intcount=0;
529. for(inti=0;i<s.length();i++){
530. charch=s.charAt(i);
531. if(ch<=0x7f){
532. count++;
533. }elseif(ch<=0x7ff){
534. count+=2;
535. }else{
536. count+=3;
537. }
538. }
539. returncount;
540. }
542. /*
543. *ReturnsanarrayofbytesrepresentingtheUTF8encodingofthespecified
544. *String.
545. */
546. privatestaticbyte[]getUTF8Bytes(Strings){
547. char[]c=s.toCharArray();
548. intlen=c.length;
549. //Countthenumberofencodedbytes...
550. intcount=0;
551. for(inti=0;i<len;i++){
552. intch=c[i];
553. if(ch<=0x7f){
554. count++;
555. }elseif(ch<=0x7ff){
556. count+=2;
557. }else{
558. count+=3;
559. }
560. }
561. //Nowreturntheencodedbytes...
562. byte[]b=newbyte[count];
563. intoff=0;
564. for(inti=0;i<len;i++){
565. intch=c[i];
566. if(ch<=0x7f){
567. b[off++]=(byte)ch;
568. }elseif(ch<=0x7ff){
569. b[off++]=(byte)((ch>>6)|0xc0);
570. b[off++]=(byte)((ch&0x3f)|0x80);
571. }else{
572. b[off++]=(byte)((ch>>12)|0xe0);
573. b[off++]=(byte)(((ch>>6)&0x3f)|0x80);
574. b[off++]=(byte)((ch&0x3f)|0x80);
575. }
576. }
577. returnb;
578. }
579. }

剩下的工作就是編寫壓縮和解壓縮的功能類了ZipUtil.java

1. packagecom.work.util;
3. importjava.io.BufferedInputStream;
4. importjava.io.BufferedOutputStream;
5. importjava.io.File;
6. importjava.io.FileInputStream;
7. importjava.io.FileNotFoundException;
8. importjava.io.FileOutputStream;
9. importjava.io.IOException;
10. importjava.io.InputStream;
12. importorg.apache.commons.logging.Log;
13. importorg.apache.commons.logging.LogFactory;
15. importcom.work.util.zip.ZipInputStream;
16. importcom.work.util.zip.ZipOutputStream;
17. importcom.work.util.zip.ZipEntry;
19. /**
20. *@projectproxool-0.9.1中的java.util.zip包和此類聯合使用
21. *@authorwangmingjie
22. *
23. */
24. publicclassZipUtil{
25. privatestaticLoglog=LogFactory.getLog(ZipUtil.class);
27. /**
28. *解壓縮文件夾。
29. *
30. *@paramsrcFilename
31. *@paramdestFilename
32. *@paramoverwrite
33. *@throwsIOException
34. */
35. publicvoidunzipDir(StringsrcFilename,booleanoverwrite)throwsIOException{
37. FilesrcFile=newFile(srcFilename);
38. //首先判斷源文件是否存在
39. if(!srcFile.exists()){
40. thrownewFileNotFoundException("Cannotfindthesourcefile:"
41. +srcFile.getAbsolutePath());
42. }
43. //判斷源文件是否可讀
44. if(!srcFile.canRead()){
45. thrownewIOException("Cannotreadthesourcefile:"
46. +srcFile.getAbsolutePath());
47. }
49. FileInputStreamfin=null;
50. BufferedInputStreaminputStream=null;
51. ZipInputStreamzipInputStream=null;
52. try{
53. fin=newFileInputStream(srcFile);
54. inputStream=newBufferedInputStream(fin);
55. zipInputStream=newZipInputStream(inputStream,"gbk");//在這裏設置編碼格式，解決文件名和備註亂碼問題
56. ZipEntryzipEntry=null;
57. StringtempFileName=null;
58. while((zipEntry=zipInputStream.getNextEntry())!=null){
60. tempFileName=zipEntry.getName();
61. if(zipEntry.isDirectory()){
62. //創建文件夾
63. FileUtil.createDirs(tempFileName,true);
64. }else{
65. tempFileName=tempFileName.replace("\\","/");
66. //System.out.println("文件夾="+tempFileName.substring(0,tempFileName.lastIndexOf("/")));
67. FileUtil.createDirs(tempFileName.substring(0,tempFileName.lastIndexOf("/")),true);
68. //System.out.println("tempFileName="+tempFileName);
69. unzipFile(zipInputStream,tempFileName);//解壓縮
70. }
71. zipInputStream.closeEntry();//關閉當前ZIP條目並定位流以讀取下一個條目。
72. //不寫上面的一句，程序也能夠正常運行。
73. }
76. }finally{
77. if(zipInputStream!=null){
78. try{
79. zipInputStream.close();
80. }catch(IOExceptionex){
81. //justignore
82. }
83. }
85. if(inputStream!=null){
86. try{
87. inputStream.close();
88. }catch(IOExceptionex){