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http断点续传简单实现(java)

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/* p|%)uA3'/  
**SiteFileFetch.java pH%K4bV)8  
*/ _kS us  
package NetFox; }PVB+i M  
import java.io.*; P<1zXs.H  
import java.net.*; F`l1I=;  
Nf1l{N  
{sLh=iK  
public class SiteFileFetch extends Thread { he,T\ };  
\;]~K6=  
JG `QJ%  
SiteInfoBean siteInfoBean = null; //文件信息Bean PuWF:'w r  
long[] nStartPos; //开始位置 _z;N|Xe  
long[] nEndPos; //结束位置 @4pN4v8U  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 chy7hPxC;  
long nFileLength; //文件长度 )u$A!+fo  
boolean bFirst = true; //是否第一次取文件 N.]8qzW  
boolean bStop = false; //停止标志 =B\ ?(  
File tmpFile; //文件下载的临时信息 hn-S$3')`  
DataOutputStream output; //输出到文件的输出流 ;rX4${h  
X!m/I i$q  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) /T?['#:r-)  
public SiteFileFetch(SiteInfoBean bean) throws IOException hikun 2  
{ ji "*=i  
siteInfoBean = bean; OP@PB|  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); _<8n]0lX3  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); \*7Tj-#  
if(tmpFile.exists ()) `k+k&t  
{ y(HR1v Q;Z  
bFirst = false; q(C+D%xB  
read_nPos(); ev>: 3_ s  
} &\A$Rj)  
else F[lHG,g-  
{ ?w.Yx$Z"  
nStartPos = new long[bean.getNSplitter()]; : v]< h  
nEndPos = new long[bean.getNSplitter()]; 6i%)'dl  
} _$\T;m>'A  
Ky+TgR  
z;-2xD0&U[  
P _9O8"W  
} )vw3Y88  
$ysC)5q.  
iVD9MHT4  
public void run() ;fuy}q8@7  
{ hod|o1C&  
//获得文件长度 E @7! :  
//分割文件 u{si  
//实例FileSplitterFetch &{$\]sv  
//启动FileSplitterFetch线程 iS"rMgq  
//等待子线程返回 E 0YXgQa  
try{ 1:-$mt_*  
if(bFirst) "ey~w=B$M  
{ ? O.&=im_  
nFileLength = getFileSize(); : "UBeo<Z  
if(nFileLength == -1)  `=oN&!  
{ SQ@@79A  
System.err.println("File Length is not known!"); DY1o!thz)  
} wJ{M&n1H  
else if(nFileLength == -2) !=ZbBUJF  
{ SgJQH7N  
System.err.println("File is not access!"); ~q<U E\H  
} TygR G+G-  
else _9<Ko.GVq  
{ 3]wV`mD  
for(int i=0;i<nStartPos.length;i++) c1c0b|B!U  
{ ;yH/GN#O  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); K]RkKMT,  
} vsc&$r3!5{  
for(int i=0;i<nEndPos.length-1;i++) rXA7<_Vg  
{ |XeuqZa  
nEndPos = nStartPos[i+1]; zdr?1=  
} 7.]ZD`"Bb  
nEndPos[nEndPos.length-1] = nFileLength; gbF.Q7?$u  
} 67d0JQTu  
} -E.EI@"  
sC/T)q2  
F$)Ki(m q  
//启动子线程 vQA: \!  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; tvP"t{C6,  
for(int i=0;i<nStartPos.length;i++) &DgIykqN  
{ 't wMvm  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), WO]dWO6Mm  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), m~# O ~)  
nStartPos,nEndPos,i); zp d4uto5  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); x }-rAr  
fileSplitterFetch.start(); gCd9"n-e  
} "}EydG"=  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), t0/fF'GZD  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); sURHj&:t|  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", "xw2@jGpG  
nEndPos = " + nFileLength); Z[|(}9v?~  
// fileSplitterFetch[nPos.length-1].start(); N1_nBQF )  
^/c&Ud  
=8[HC}s|$  
//等待子线程结束 0LxA+  
//int count = 0; ;gf^;%FK  
//是否结束while循环 Up`zVN59.  
boolean breakWhile = false; ]U]{5AA6  
xZBmQ:s',S  
PZQ}G*p3  
while(!bStop) ceAK;v o  
{ lv,<[Hw1  
write_nPos(); d!!5'/tmS  
Utility.sleep(500);  u"tv6Qp  
breakWhile = true; X=-pNwO   
|Zz3X  
"{|9Yis=  
for(int i=0;i<nStartPos.length;i++) r%F{1.  
{ 'H:lR1(,  
if(!fileSplitterFetch.bDownOver) Rom|Bqo;  
{ BB9Z?}  
breakWhile = false; b bX2D/  
break; B2VUH..am  
} 6M F%$K3  
} a(!:a+9WOP  
if(breakWhile) A:>G:X5t  
break; amOBUD5Ld`  
SI U"cO4  
wC;N*0Th  
//count++; ]e 81O#t3  
//if(count>4) R:zjEhH )  
// siteStop(); >AV?g8B;  
} -49OE*uF  
_<&IpT{w+  
KD=T04v  
System.err.println("文件下载结束!"); J %URg=r  
} u JGYXlLE  
catch(Exception e){e.printStackTrace ();} }Z"<KF  
} ^2XoYgv  
&H<-joZ)Z\  
ewD61Y8-  
//获得文件长度 !ZHPR:k|  
public long getFileSize() FX 0^I 0  
{ vV,H@WK  
int nFileLength = -1; 4>gk XfTF  
try{ XV]`?  
URL url = new URL(siteInfoBean.getSSiteURL()); %.[t(F  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); |{<g-)  
httpConnection.setRequestProperty("User-Agent","NetFox"); n"$D/XJO  
%mg |kb6n  
=D<46T=(RB  
int responseCode=httpConnection.getResponseCode(); YB.r-c"Y  
if(responseCode>=400) ZmUS}   
{ hI]KT a  
processErrorCode(responseCode); P*Uu)mG)G  
return -2; //-2 represent access is error |&o%c/  
} /\(0@To  
mq do@  
mS6L6)] S  
String sHeader; OANn!nZ.  
#P<v[O/rA  
JEGcZeq)  
for(int i=1;;i++) 26&^n Uy  
{ AS'a'x>8>,  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 79z(n[^  
//Utility.log(in.readLine()); RV.*_FG  
sHeader=httpConnection.getHeaderFieldKey(i); 52,pCyU  
if(sHeader!=null) qJKD| =_  
{ hT#[[md"  
if(sHeader.equals("Content-Length")) `fj(xrI  
{ mM&H; W  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 8S &`  
break; [ wi "  
} v_En9~e^n  
} o *S"`_   
else 1B}6 zJ  
break; T1LtO O  
} !Yz~HO,u+  
} 'cu( Sd}  
catch(IOException e){e.printStackTrace ();} z ~T[%RjO  
catch(Exception e){e.printStackTrace ();} @_YlHe&W  
y!h$Z6.  
g < M\zD  
Utility.log(nFileLength); OIe {Sx{y  
)UO:J7K  
FU E/uh  
return nFileLength; OXK?R\ E+  
} ZjF$zVk  
~ucOQVmz@  
.yd{7Te  
//保存下载信息(文件指针位置) 80x %wCY`  
private void write_nPos() 0bVtku K;G  
{ FDkRfhK  
try{ VX2 KE@  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 1.4]T, `  
output.writeInt(nStartPos.length); s 'u6Ep/V  
for(int i=0;i<nStartPos.length;i++) ^8a,gA8.  
{ -"UK NB!  
// output.writeLong(nPos); (&=-o(  
output.writeLong(fileSplitterFetch.nStartPos); k:nr!Y<  
output.writeLong(fileSplitterFetch.nEndPos); [>=D9I@~  
} K, WNM S  
output.close(); ]3BTL7r  
} m1heU3BUWU  
catch(IOException e){e.printStackTrace ();} Eg FV  
catch(Exception e){e.printStackTrace ();} ;@Alr?y  
} ;^^u_SuH  
u`xmF/jhQ  
DvKM[z3j  
//读取保存的下载信息(文件指针位置) dw5.vXL`  
private void read_nPos() n{6XtIoYq  
{ 6@t4pML  
try{ U"v(9m@  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); No=Ig-It  
int nCount = input.readInt(); G^ZL,{  
nStartPos = new long[nCount]; @kenv3[Lc  
nEndPos = new long[nCount]; FVPhk2  
for(int i=0;i<nStartPos.length;i++) H 0aDWFWS  
{ ~*GJO74  
nStartPos = input.readLong(); J}Bg<[n  
nEndPos = input.readLong(); ka0T|$ u(s  
} 5?&k? v@  
input.close(); rbHrG<+7zO  
}  Xai ,  
catch(IOException e){e.printStackTrace ();} CS)&A4`8  
catch(Exception e){e.printStackTrace ();} ;EP7q[  
} J^R))R=  
s/Fc7V!;  
Z,M?!vK  
private void processErrorCode(int nErrorCode) Py^F},?J  
{ tV<}!~0,*  
System.err.println("Error Code : " + nErrorCode); KwndY,QD  
} Og4 X3QG  
2asA]sY  
R] tHd=kf  
//停止文件下载 5)+(McJC  
public void siteStop() AyB-+oTf(  
{  oJ ~ZzW  
bStop = true; E3<jH  
for(int i=0;i<nStartPos.length;i++) Kn SXygT  
fileSplitterFetch.splitterStop(); QXY-?0RO#  
};o6|e:2E  
*]nha1!S  
} OmQSNU.our  
} UO47XAO  
//负责部分文件的抓取 zmQ V6o=k  
**FileSplitterFetch.java %<6oKE  
*/ IHZ WNT2  
package NetFox; 'S@%  
iA3d[%tBb  
FbO-K-  
import java.io.*; $Q{)AN;m  
import java.net.*; +Pd&YfU9  
_A|1_^[G(  
,UopGlA ,  
public class FileSplitterFetch extends Thread { 4(o: #9I  
i[`nu#n/  
Q6 @}t&k4C  
String sURL; //File URL y44FejH(v  
long nStartPos; //File Snippet Start Position RIJ+]uir4  
long nEndPos; //File Snippet End Position T8h.!Vef  
int nThreadID; //Thread's ID sesr`,m.,  
boolean bDownOver = false; //Downing is over :~3sW< P R  
boolean bStop = false; //Stop identical 1k6f|Al -  
FileAccessI fileAccessI = null; //File Access interface Wp/!;  
H0Qpc<Z4/  
pg1o@^OuL  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException MNzq,/Wf  
{ wv>Pn0cO  
this.sURL = sURL; }jBr[S5  
this.nStartPos = nStart; AR\>P  
this.nEndPos = nEnd; JP)/ O!  
nThreadID = id; '}dlVf  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 pN6!IxN$  
} "(PJh\S>S  
3Q*K+(`{  
r5%K2q{  
public void run() #F@53N  
{ %_;q<@9)  
while(nStartPos < nEndPos && !bStop) \u ?z:mV  
{ M7^PWC  
\~UyfVPRT  
Ck8`$x&t  
try{ O Ul+es  
URL url = new URL(sURL); N3g[,BE  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); _m;0%]+  
httpConnection.setRequestProperty("User-Agent","NetFox"); EKZ40z`  
String sProperty = "bytes="+nStartPos+"-"; XL c&7  
httpConnection.setRequestProperty("RANGE",sProperty); zuUf:%k}I  
Utility.log(sProperty); ;ZPAnd:pb  
.%_scNP  
d!7cIYVZ  
InputStream input = httpConnection.getInputStream(); KT~J@];Fb  
//logResponseHead(httpConnection);  Z+`mla  
S!A)kK+  
A ^ $9[_  
byte[] b = new byte[1024]; $j0] +vT  
int nRead; #~*fZ|sq+3  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ';us;xR#  
{ I~y[8  
nStartPos += fileAccessI.write(b,0,nRead); 3C 84b/A  
//if(nThreadID == 1) ,uqSq  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); AX}l~ sv  
} \!j{&cJ  
S9d+#6rn  
*X+T>SKL  
Utility.log("Thread " + nThreadID + " is over!"); (`x6QiG!  
bDownOver = true; CT+pkNC  
//nPos = fileAccessI.write (b,0,nRead); jJdw\`  
} cG1-.,r  
catch(Exception e){e.printStackTrace ();} oNY;z-QK  
} \g< M\3f  
} PeEf=3  
:]iV*zo_  
*i|O!h1St  
//打印回应的头信息 NlXHOUw)u  
public void logResponseHead(HttpURLConnection con) x!fvSoHp  
{ \gaGTc2&  
for(int i=1;;i++) Ug*:o d  
{ Os' 7h  
String header=con.getHeaderFieldKey(i); P9; =O$s  
if(header!=null) W=41jw  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); D@*<p h=  
Utility.log(header+" : "+con.getHeaderField(header)); ,2q LiE>  
else -twV?~f  
break; rU`#3}s  
} SjV;& 1Z/  
} "& 'h\  
cdVh_"[  
Ql&5fyW  
public void splitterStop() M@EML @~  
{ \&ra&3o  
bStop = true; hE0 p> R8  
} O`5PX(J1&  
Sx?IpcPSm  
jR`q  y<  
} Tm~a& p  
L^uO.eI"m  
\L}aTCvG  
/* &+;z`A'|8  
**FileAccess.java vggyQf%  
*//文件访问(定位,写) <gRv7 ?V[z  
package NetFox; ysm)B?+k  
import java.io.*; ku3Vr\s  
<o,]f E[  
f#}P>,TP  
public class FileAccessI implements Serializable{ K n%[&  
37Ux2t  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ]+\;pb}bq  
RandomAccessFile oSavedFile; ~6L\9B )  
long nPos; z}&w7 O#   
:5IbOpVM  
PrqN5ND  
public FileAccessI() throws IOException  vp7J';  
{ kaf4GME]  
this("",0); xU+c?OLi  
} <|9s {z  
l\< *9m<  
>utm\!Gac  
public FileAccessI(String sName,long nPos) throws IOException INqD(EG   
{ KR4X&d6  
oSavedFile = new RandomAccessFile(sName,"rw"); B|U*2|e  
this.nPos = nPos; k"X<gA  
oSavedFile.seek(nPos); T {Q]  
} - `F#MN  
C# IV"Pkq  
NF+^  
public synchronized int write(byte[] b,int nStart,int nLen) It>8XKS  
{ F33&A<(,  
int n = -1; ={P  
try{ 78&(>8@m  
oSavedFile.write(b,nStart,nLen); a<-NB9o~v  
n = nLen; " UaUaSg#  
} ~/s(.oji  
catch(IOException e) 6cH.s+  
{ cnJ(Fv_F$  
e.printStackTrace (); &?C% -"|c  
} s<,[xkMB  
H:byCFN-  
tmEF7e`(o  
return n; &U/7D!^X  
} F;$z[z  
7 -yf  
pv);LjF  
} s8;/'?K  
t;X  !+  
#rnO=N8  
/* 5#kN<S!  
**SiteInfoBean.java -DD2   
*/ /NRdBN  
package NetFox; L-Qc[L  
s/#L?[YH  
Xm,w.|dx  
public class SiteInfoBean { 1KwUp0% &  
iV<4#aBg  
1_$y bftS  
private String sSiteURL; //Site's URL S%J$.ge  
private String sFilePath; //Saved File's Path =_~bSEqyRI  
private String sFileName; //Saved File's Name :uwB)G  
private int nSplitter; //Count of Splited Downloading File sk* AlSlM  
j6x1JM  
n<RvL^T=  
public SiteInfoBean() m/}(dT;  
{//nSplitter的缺省值为5  g=W1y  
//default value of nSplitter is 5 $OEhdz&Fi  
this("","","",5); Q'-g+aN  
} :: IAXGH)  
oAaUXkQE  
e(nT2E  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) #+$pE@u7A  
{ n?uVq6c  
sSiteURL= sURL; ,m ^q >  
sFilePath = sPath; .3Ex=aQcX  
sFileName = sName; *^agwQ`  
this.nSplitter = nSpiltter; F?"#1j e  
|VC|@ Q  
fePt[U)2  
} U Px7u%Do  
.A 12Co  
}EFMJ,NQ  
public String getSSiteURL() ^|Bpo(  
{ #a7 Wx}  
return sSiteURL; \X&LrneR"t  
} 7-Bttv{  
bEx8dc`Q  
NlLgXn!  
public void setSSiteURL(String value) & !0[T   
{ .FV wZ:d  
sSiteURL = value; t<sy7e='  
} N=4`jy =  
!l2=J/LJj  
qU!xh )  
public String getSFilePath() }~/u%vI@M5  
{ #"PI%&  
return sFilePath; Tz/=\_}  
} 4q%hn3\  
m3o+iYkMD  
WEX6I 16  
public void setSFilePath(String value) @log=^  
{ _Nze="Pt  
sFilePath = value; H|V q  
} KBVW <;C$  
R^t )~\d  
Hzos$1DJ  
public String getSFileName() Fh)`A5#  
{ wD9Gl.uQ  
return sFileName; bD*z"e  
} . Y@)3  
w?u4-GT  
H~fX >6>  
public void setSFileName(String value) mC-'z  
{ PH,MZ"Z%  
sFileName = value; N%3 G\|~Q  
} bBwMx{iNNz  
~lg1S  
%~z/,[wk  
public int getNSplitter() BgPwIK x  
{ 'j6)5WL$  
return nSplitter; "0BuQ{CQ  
} 'ju  
e-@=QI^,  
o XKH,r  
public void setNSplitter(int nCount) ZmT N  
{ (<.uvq61  
nSplitter = nCount; {u 7%Z}<0  
} 8vP:yh@  
} a04I.5!  
^LaOl+;S  
bKAR}JM&  
/* 6x6xv:\  
**Utility.java c UJUZ@ol  
*/ Z:TW{:lrI  
package NetFox; X?3?R\/  
IiX`l6L~W  
^ W/,Z`  
public class Utility { WziX1%0$n  
gOk<pRcTb=  
|dP[_nh?  
public Utility() R9dC$Y]\M  
{ g 0=Q>TzY  
zYL</!6a[  
PxqRb  
} |Wo_5|E  
~c;D@.e\  
//线程睡眠 NTj:+z0  
public static void sleep(int nSecond) 6Vq]AQx  
{ BK+(Uf;g  
try{ HizMjJ|  
Thread.sleep(nSecond); Muhq,>!U  
} tA,#!Z0  
catch(Exception e) OfSy_#aEK  
{ S7/0B4[  
e.printStackTrace (); E~k_4z% M  
} ;t^8lC?>V  
} oM')NIW@  
9!aQ@ J^  
//日志 NrC (.*?m  
public static void log(String sMsg) h[Hn*g  
{ M=HP!hn  
System.err.println(sMsg); MV+S.`R  
} !a(#G7zA  
E`^?2dv+/  
!'ylh8}  
public static void log(int sMsg) e3|@H'~k  
{ X?RnP3t~  
System.err.println(sMsg); kO1.27D  
} C>1fL6ct  
} M*& tVG   
X={n9*Sd8  
f]P&>j|  
/* ?O]iX;2vM  
**TestMethod.java !!WSGZUR  
*/ ^p'iX4M  
package NetFox; I eQF+Xz  
;OE=;\  
Q%x |  
public class TestMethod { 3A~53W$M  
n'dxa<F2|  
`0]kRA8=  
public TestMethod() ?<Tt1fpG  
{ ///xx/weblogic60b2_win.exe Do&em8i z  
try{ R0 g-  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 1|+Z mo"  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Pf?*bI  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ,gvv297  
fileFetch.start(); C2 ~t  
} 6NvdFss'A{  
catch(Exception e){e.printStackTrace ();} )\iO wA  
hx'p0HDta  
@M:Uf7  
} %*>ee[^L ,  
\~3g*V  
jz\LI  
public static void main(String[] args) yNw YP%"y  
{ 8T}Ycm5}  
new TestMethod(); M.h)]S>  
} [sM~B  
} qre.^6x  
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