http断点续传简单实现（java)

/* v5M4Rs&t  
**SiteFileFetch.java YmC}q20;  
*/ J+P<zC  
package NetFox; tW UI?\  
import java.io.*; <U3X4)r  
import java.net.*; @vl$[Z|  
!8G)`'  
NVMn7H}>  
public class SiteFileFetch extends Thread { B'yjMY![  
M@.l# [@U  
Q5ASN"_  
SiteInfoBean siteInfoBean = null; //文件信息Bean H^-Y]{7  
long[] nStartPos; //开始位置 :+"4_f0  
long[] nEndPos; //结束位置 MqZ"Js  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 4t[7lL`Z  
long nFileLength; //文件长度 U6&`s%mIa  
boolean bFirst = true; //是否第一次取文件 E+/Nicn=  
boolean bStop = false; //停止标志 tc'iKJ5)  
File tmpFile; //文件下载的临时信息 x$d[Ovw-  
DataOutputStream output; //输出到文件的输出流 h?xgOb!4  
bN_e~z  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） )k(K/m  
public SiteFileFetch(SiteInfoBean bean) throws IOException __g?xw  
{ @7nZjrH  
siteInfoBean = bean; .) Ej#mk  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); k?fz @H8D(  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); j#//U2VdN  
if(tmpFile.exists ()) T
Q(q[:>  
{ %tVU Rj  
bFirst = false; FDl/7P`b(  
read_nPos(); C'I&<  
} sx#O3*'>1  
else DSLX/uo1  
{ 5sJ>+Rg  
nStartPos = new long[bean.getNSplitter()]; fJ*^4
  
nEndPos = new long[bean.getNSplitter()]; (9u`(|x  
} k{+cFG\C&  
0
T`Qoo>u  
4FaO+Eo,8  
4~}NB%,  
} ZD&F ,2v  
$V87=_}  
O!"K'Bm  
public void run() 'UX^]  
{ eX$KH;M  
//获得文件长度 toY_1  
//分割文件 ^&<M""Z  
//实例FileSplitterFetch ]H/,Q6Q  
//启动FileSplitterFetch线程 gkmof^  
//等待子线程返回 U;bx^2<m  
try{ )xcjQkb  
if(bFirst) VZqCFE3  
{ &4OJJ9S  
nFileLength = getFileSize(); Ar>B_*dr  
if(nFileLength == -1) 7]rIq\bM  
{ nFlN{_/  
System.err.println("File Length is not known!"); p7YYAh@x\  
} Osqk#Oh  
else if(nFileLength == -2) lj]M 1zEz&  
{ "e-Y?_S7R8  
System.err.println("File is not access!"); .JKH=?~\  
} fn<dr(Dx  
else JzEg`Sn^  
{ E{V?[HcWq  
for(int i=0;i<nStartPos.length;i++) :P-H8*n""  
{ iFUiw&  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 3V]dl)en%  
} }Cu:BD.zQ  
for(int i=0;i<nEndPos.length-1;i++) uf?;;wg  
{ sK%b16#  
nEndPos = nStartPos[i+1]; __}SHU0R  
} r^R
a`:ca  
nEndPos[nEndPos.length-1] = nFileLength; gOg7:VPG  
} ]C^ #)
7  
} CG%bZco((  
mPA)G,^  
7FH-l(W  
//启动子线程 =Z.0-C>W  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ?eTZ>o.p/  
for(int i=0;i<nStartPos.length;i++) 7Q!ksp  
{ [7><^?t V  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), diXWm-ZKL  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ,It0brF  
nStartPos,nEndPos,i); .M:&Aj)x16  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos);  (
7X  
fileSplitterFetch.start(); QI[WXxp  
} :0@0muo  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), _EMXx4J  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 4]1/{</B|  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 6?,qysm06  
nEndPos = " + nFileLength); ~;oXLCL0})  
// fileSplitterFetch[nPos.length-1].start(); SXsszb:_  
_!2lnJ4+5  
|4DN2P  
//等待子线程结束 pS8\B  
//int count = 0; E#P#{_BR^  
//是否结束while循环 2Ug_3ZuU  
boolean breakWhile = false; fOMaTnm'  
h_t`)]-  
3fLdceT  
while(!bStop) % (h6m${j  
{ Y9mhD
znS  
write_nPos(); Gw)y<h  
Utility.sleep(500); PZ/tkw  
breakWhile = true; ~xG/yPl  
V(cU/Aia^  
l8E))oz1T  
for(int i=0;i<nStartPos.length;i++) t5 >ma:^j  
{ Ju>QQOxi|  
if(!fileSplitterFetch.bDownOver) dk
g`T#}  
{ 1a9' *[  
breakWhile = false; [`tOhL  
break; RV@B[:  
} 5!ngM  
} ;r2DQg"#@  
if(breakWhile) f IV"U  
break; C1AX  
uNy-r`vg  
<]?71{7X  
//count++; g Nz  
//if(count>4) Hva!6vwO%O  
// siteStop(); JAHmmNlW  
} k|xmZA*  
DzhLb8k  
T}\
>8EEG  
System.err.println("文件下载结束！"); !=30
s;-  
} ,w"cY?~<  
catch(Exception e){e.printStackTrace ();} Sy?^+JdM/  
} trwo(p  
c2V_|
oL  
kPOk.F%)  
//获得文件长度 ]pNM~,  
public long getFileSize() oBmv^=cH  
{ mmwc'-jU:  
int nFileLength = -1; idBdaZg  
try{ o?O ZsA  
URL url = new URL(siteInfoBean.getSSiteURL()); lLVD`)  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); R)d_0Ng  
httpConnection.setRequestProperty("User-Agent","NetFox"); 4grV2xtX  
3K(/=  
\aSc2Ml]3n  
int responseCode=httpConnection.getResponseCode(); 6!)hl"  
if(responseCode>=400) bZSt<cH3  
{ =?L16mu1&  
processErrorCode(responseCode); =WN8><K!  
return -2; //-2 represent access is error Qv,ORm h5  
} Lm$KR!z  
KdiJ'K.  
Mb_"M7  
String sHeader; {uwPP2YD,  
H^*[TX=#[  
CWZv/>,%  
for(int i=1;;i++) j}lne^ h  
{ !]"M]tyv\  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ZLaht(`+  
//Utility.log(in.readLine()); 6k')12~'  
sHeader=httpConnection.getHeaderFieldKey(i); hJFxT8B/  
if(sHeader!=null) "pX|?ap  
{ 0dx%b677d  
if(sHeader.equals("Content-Length")) @ #J2t#  
{ NWwKp?  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ^Gbcs l~Gj  
break; 9XUYy2{G  
} PtPx(R3  
} xxGQXW  
else E0i!|H  
break; EP4?+"Z  
} g:^Hex?Yfd  
} Cjt].XR@  
catch(IOException e){e.printStackTrace ();} R8.@5g_  
catch(Exception e){e.printStackTrace ();} Q&$2F:4f&  
Y}}1]}VIK  
</9c=GoJ  
Utility.log(nFileLength); BDL[C<d(  
(eT9N_W  
c-~i=C]  
return nFileLength; &6GW9pl[  
} 9u^za!pE  
U2Siw  
M;g"rpM  
//保存下载信息（文件指针位置） )fuAdG  
private void write_nPos() }uD*\.  
{ ZDK+>^A)  
try{ FKtCUq,:  
output = new DataOutputStream(new FileOutputStream(tmpFile)); q.hpnE~#lh  
output.writeInt(nStartPos.length); W)2
k>cS  
for(int i=0;i<nStartPos.length;i++) {Y+e|B0  
{ 4\U"e*  
// output.writeLong(nPos); }P!:0w3  
output.writeLong(fileSplitterFetch.nStartPos); ?S)Pv53>}  
output.writeLong(fileSplitterFetch.nEndPos); $*fEgU% c  
} TD;u"  
output.close(); o|KmKC n>  
} Fyz1LOH[X  
catch(IOException e){e.printStackTrace ();} UZJs!#P  
catch(Exception e){e.printStackTrace ();} m2
%
 
} Q9X+H4`}y  
it j&L <e  
nwJub$5  
//读取保存的下载信息（文件指针位置） ,=u!hg  
private void read_nPos() y
BqKldl  
{ >U:.5Tch'V  
try{ *6(/5V  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); nqYarHi  
int nCount = input.readInt(); V[*<^%  
nStartPos = new long[nCount]; ~c,+)69"T  
nEndPos = new long[nCount]; RLVz"=  
for(int i=0;i<nStartPos.length;i++) hs)_h^P   
{ d~CZ9h  
nStartPos = input.readLong(); of_Om$  
nEndPos = input.readLong(); ['c*<f" D2  
} 7?Twhs.O  
input.close(); p1s& y0:d  
} od/Q"5t[p  
catch(IOException e){e.printStackTrace ();} mnYzn[d3U  
catch(Exception e){e.printStackTrace ();} c=B!\J<1  
} }1Hy[4B(k\  
Nk\/lK\  
xCU pMB7  
private void processErrorCode(int nErrorCode) ?DM!=.]  
{ |dqAT.  
System.err.println("Error Code : " + nErrorCode); K}dvXO@=|c  
} C%P"\>5@  
x*_'uPoS  
r[nvgzv@  
//停止文件下载 O3L:v{Kn  
public void siteStop() ];{CNDAL2  
{ K{G\=yJ((  
bStop = true; d?GB#N|+g  
for(int i=0;i<nStartPos.length;i++) covK6SH  
fileSplitterFetch.splitterStop(); dr=h;[Q'  
?&XpwJw:~  
8}OII\  
} >` |sBx  
} H3|x  
//负责部分文件的抓取 w2]]##J  
**FileSplitterFetch.java $0~_)$i:  
*/ ^,fMs:  
package NetFox; kSqMI'89  
`Yo!sgPO\  
y=e|W=<D&  
import java.io.*; Tm
l>>O  
import java.net.*; hLSas#B>  
LyT[  
pTcN8E&Unz  
public class FileSplitterFetch extends Thread { jW.IkG[|  
WD'[|s\  
wn>?r ?KIB  
String sURL; //File URL lDtl6r/  
long nStartPos; //File Snippet Start Position )WF*fcx{  
long nEndPos; //File Snippet End Position KZsJ_t++!W  
int nThreadID; //Thread's ID K1|xatx1V  
boolean bDownOver = false; //Downing is over ?wj1t!83  
boolean bStop = false; //Stop identical $s9YU"  
FileAccessI fileAccessI = null; //File Access interface "xMnD(p  
,uhOf! |  
k%sh;1.  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException uRRp8hht  
{ #7,;/rtO7  
this.sURL = sURL; 8CGjI?j  
this.nStartPos = nStart; F@@6D0\X?  
this.nEndPos = nEnd; @O&;%IZMY  
nThreadID = id; G+W0X  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ;fKFmY41  
} iriF'(1  
~`CWpc:  
4wx_@8  
public void run() k9oLJ<.k  
{ e_t""h4D  
while(nStartPos < nEndPos && !bStop) <.c#l':  
{ 8s<t* pI2  
y(Ck j"  
`Ct fe
8  
try{ +J(@.  
URL url = new URL(sURL); rTYM
N  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); (Q][d+} /  
httpConnection.setRequestProperty("User-Agent","NetFox"); 6nHyd<o  
String sProperty = "bytes="+nStartPos+"-"; -@G,Ry-\t  
httpConnection.setRequestProperty("RANGE",sProperty); `RLn)a  
Utility.log(sProperty); !:<n]-U  
Hyz:i)2  
+ Awo\;@,  
InputStream input = httpConnection.getInputStream(); U=\!`_f':  
//logResponseHead(httpConnection); kmF@u@5M  
>_LZD4v!<  
H6%%n X  
byte[] b = new byte[1024]; CUZ ;<Pn  
int nRead; \6c8Lqa  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) t8upS u|  
{ Yuqt=\? #  
nStartPos += fileAccessI.write(b,0,nRead); xa|/P#q  
//if(nThreadID == 1) .0u@PcE:O  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); C:@JL
ZB  
} u
O}U
vMW  
J^<}fRw  
{Z{!tR?+  
Utility.log("Thread " + nThreadID + " is over!"); ~jn~M_}K  
bDownOver = true; u|D|pRM-LT  
//nPos = fileAccessI.write (b,0,nRead); ;*409P  
} $Z{Xt*  
catch(Exception e){e.printStackTrace ();} 2<8JY4]!]  
} ' lMPI@C6r  
} s^Rig[  
+*ZF52hy|  
6-h(305A  
//打印回应的头信息 u:s[6T0  
public void logResponseHead(HttpURLConnection con) ya0D50m  
{ tc<ly{ 1c  
for(int i=1;;i++) kF29~  
{ 0}iND$6@a  
String header=con.getHeaderFieldKey(i); q[MZSg  
if(header!=null) z,q1TU
9  
//responseHeaders.put(header,httpConnection.getHeaderField(header));
M
7g6m  
Utility.log(header+" : "+con.getHeaderField(header)); S{F'k;x/5  
else YVS~|4hu?i  
break; ;7w4BJcq']  
} eg Zb)pP  
} 4vb
tB2  
i*ErxWzu  
68-2EWq  
public void splitterStop() l#k&&rI5x.  
{ 4<Q^/-W  
bStop = true; Rx%SeM2  
} T?V!%AqY:  
v[I
,N$:  
$`Hb-  
} Fl0 :Z  
:o+&>z  
19.oW49Sw  
/* ;ro%Wjg`}  
**FileAccess.java ?kKr/f4N  
*//文件访问(定位，写) U>=& 2Z2?  
package NetFox; Z_}[hz$  
import java.io.*; >%{H>?Hn  
(nLT8{>0  
>* >}d%  
public class FileAccessI implements Serializable{ s(MLBV5)w  
]'!$T72  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 1O@ D  
RandomAccessFile oSavedFile; 6A,-?W'\  
long nPos; sbV {RSl  
l0-zu6iw  
mel(C1b"j/  
public FileAccessI() throws IOException t2 0Es  
{ 40)Ti  
this("",0); 4fa2_  
} w_lN[u-L  
S<bsrS*$  
;j^C35  
public FileAccessI(String sName,long nPos) throws IOException 8ZPjzN>c6  
{ mKN#dmw6  
oSavedFile = new RandomAccessFile(sName,"rw"); N!iugGL  
this.nPos = nPos; 5}MjS$2og  
oSavedFile.seek(nPos); 4J${gcju  
} 7r,h[9~e  
99tKs  
$=GnoS  
public synchronized int write(byte[] b,int nStart,int nLen) TM2pE/P  
{ %6eQ;Rp*  
int n = -1; +(l(|lQy$  
try{ >4&s7][Q|  
oSavedFile.write(b,nStart,nLen); NT&skrzW  
n = nLen; >y{oC5S  
} L92vb zP  
catch(IOException e) fA{t\  
{ .tH[A[/1 a  
e.printStackTrace (); .\:{6_  
} B(B77SOb  

.qGfLvx%  
gOL-b9W  
return n; |QcE5UC  
} 7;x}W-`iF  
%MH!L2|  
^a{cK  
} LZF%bJv  
$zv&MD!&h  
nTQ&nu!  
/* 0AWOdd>.  
**SiteInfoBean.java rIJv(&l  
*/ FQW{c3%qZ  
package NetFox; *p Q'w  
Vnvfu!>(  
vE<z0l  
public class SiteInfoBean { qnCJrY6]  
5nSi2
9C  
x}B_;&>&"_  
private String sSiteURL; //Site's URL >3&Oe  
private String sFilePath; //Saved File's Path (dgBI}Za  
private String sFileName; //Saved File's Name 2=V~n)'a  
private int nSplitter; //Count of Splited Downloading File $$f89, h  
5eJMu=UpR  
09L"~:rg  
public SiteInfoBean() Q$XNs%7w5,  
{//nSplitter的缺省值为5 (N 0kTi]b  
//default value of nSplitter is 5 gof'NT\c  
this("","","",5); rf=ndjrH  
} ZW)_dg9  
-gK*&n~  
vn5O8sD  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) odaCKhdk  
{ L2<IG)oXU  
sSiteURL= sURL; <2,NWn.  
sFilePath = sPath; :N>n1tHL;A  
sFileName = sName; zPn2  
this.nSplitter = nSpiltter; 9_ru*j\  
!)-)*T  
g;mX{p_@  
} A8oTcX_  
o<Y[GW1pg  
X5w_ }Nhe  
public String getSSiteURL() ])tUXU>  
{ }{y(&Oy3Y  
return sSiteURL; 7*I:cga  
} )
p!.V(,  
=Owr l'@|T  
v-ZTl4j$  
public void setSSiteURL(String value) -J'0qN!  
{ Zc|V7+Yx  
sSiteURL = value; Y7_2pGvZ  
} Z;M th#  
c]]e
(  
r~q3nIe/,  
public String getSFilePath() $LOwuvu>  
{ AJ"a  
return sFilePath; U"L7G$  
} MR3\7D+9y  
Y6:b  
\qZ>WCp>r  
public void setSFilePath(String value) J{qsCJiB  
{ T:!f_mu|  
sFilePath = value; Sk7sxy<F'  
} /C\tJ
s  
|9Pi*)E  
;6AanwR6  
public String getSFileName() \S]` { kY,  
{ G5,g$yNs  
return sFileName; ?ytY8`PC  
} a>8&B  
6QM$aLLP?  
dng^#|X)?  
public void setSFileName(String value) R>T9 H0  
{ CAa&,ZR  
sFileName = value; PP&9ORG  
} [x8_ax}w  
1G<S'd+N  
M'|?*aNK  
public int getNSplitter() !=bGU=^  
{ ;}KT 3Q<^  
return nSplitter; [MXyOE  
} 5hj _YqQ7  
;FnU[Q`M#L  
C/#?S=w`4  
public void setNSplitter(int nCount) ;6}> Shs  
{ 1uco{JX<S  
nSplitter = nCount; *)D$w_06S  
} 2|\WaH9P  
} O<()T6  
\&\U&^?  
D5"Xjo*  
/* MN^d28^/  
**Utility.java m(KBg'kQ  
*/ w\lc;4U   
package NetFox;
\N[2-;[3  
>J) 9&?  
Uu[dx}y  
public class Utility { \5P 5N]]  
q#PMQR"C  
u9u'!hAGH  
public Utility() Nh[H[1"J  
{ C Ef*:kr  
jp880}  
Rrw6\iO  
} 8DkZ@}  
o3cE.YUF  
//线程睡眠 PS$g*x  
public static void sleep(int nSecond) 0iI|eE o  
{ M3!4,_!~  
try{ 'l $ViNq;  
Thread.sleep(nSecond); '37 <+N  
} 'OI(MuSn  
catch(Exception e) Jp"[`
m  
{ Vy7 )_D  
e.printStackTrace (); 45
Lzq6  
} oq9gFJG(  
} &G)/i*  
nSpOTQ  
//日志 V;d<S@$  
public static void log(String sMsg) U8OVn(qV  
{ $CDRIn50  
System.err.println(sMsg); nhy:5eSK  
} #H;1)G(/  
m+QZ|  
cJ#n<Rsz  
public static void log(int sMsg) *r)dtI*  
{ I{i6e'.jP  
System.err.println(sMsg); }poLHS/  
} 1vinO!  
} GG
%*d]  
^G14Z5.  
<9
]J/w+  
/* eC
jyx|:J  
**TestMethod.java [&sabM`Ul  
*/ -ND1+`yD  
package NetFox; -_BX\iP{  
nCDGPz
J  
2oo\SmO]  
public class TestMethod { J\hqK*/8  
Ze?n Q-  
?{%"v\w  
public TestMethod() 'HJ<"<  
{ ///xx/weblogic60b2_win.exe .UYhj8  
try{ =g|5VXW5  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); !NMiWG4R  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); {wD:!\5  
SiteFileFetch fileFetch = new SiteFileFetch(bean); e"|ZTg+U  
fileFetch.start(); i,2eoM)FB  
} 3LZvlcLb  
catch(Exception e){e.printStackTrace ();} mhI  
{7Hc00FM  
7c83g2|%   
} F_@?'#m  
vi]cl=S  
63QF1*gPH  
public static void main(String[] args) Q@[(0R1  
{ U~w8yMxX  
new TestMethod(); KGGJ\r6  
} R-tZC9 @  
} y1B'_s  
点击下载更多相关资料