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http断点续传简单实现(java)

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/* `[:1!I.}-  
**SiteFileFetch.java 5 ^J8<s@_  
*/ UuC"-$:  
package NetFox; SA n=9MG  
import java.io.*; zp-~'kIJ  
import java.net.*; K}3"KC  
'"\Mjz)/  
xWb?i6)z&  
public class SiteFileFetch extends Thread { by<@Zwtf  
.LcE^y[V  
'<D}5u7 2  
SiteInfoBean siteInfoBean = null; //文件信息Bean 78~V/L;@S2  
long[] nStartPos; //开始位置 poFjhq /#(  
long[] nEndPos; //结束位置 PxD}j 2Kd  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 9QZwUQ  
long nFileLength; //文件长度 J3S+| x h~  
boolean bFirst = true; //是否第一次取文件 -?`l<y(  
boolean bStop = false; //停止标志 N_[ Q.HD"  
File tmpFile; //文件下载的临时信息 $v@$oPmMj  
DataOutputStream output; //输出到文件的输出流 rPvX8*) tV  
pdqa)>$  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) aMg f6veM  
public SiteFileFetch(SiteInfoBean bean) throws IOException IMrOPwjc  
{ [y;ZbfMP|o  
siteInfoBean = bean; J,KTc'[  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); -mo ' $1  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); %)ov,p |  
if(tmpFile.exists ()) T\CQ  
{ @Hdg-f>y]  
bFirst = false; > 0)`uJ  
read_nPos(); VZbIU[5  
} 6v)eM=   
else ^F9zS `Yz2  
{ ! -nm7Q  
nStartPos = new long[bean.getNSplitter()]; :Zo2@8@7  
nEndPos = new long[bean.getNSplitter()]; 0 3 $ W  
} @$} \S  
pFRnPOv  
p&doQh  
EoW zHa  
} VZ@@j[F(  
;QD;5 <1  
sn`?Foh  
public void run() K :ptfD  
{ Bin&:%|9?  
//获得文件长度 3"D00~  
//分割文件 x+`3G.  
//实例FileSplitterFetch R:x04!}  
//启动FileSplitterFetch线程 [;8fL  
//等待子线程返回 Xb 1^Oj  
try{ #N}}8RL  
if(bFirst) sswAI|6ou  
{ pvxqeC9`  
nFileLength = getFileSize(); W?Abx  
if(nFileLength == -1) g c=|< (  
{ -3U} (cZ*  
System.err.println("File Length is not known!"); 5z]KkPQ  
} |noTIAI  
else if(nFileLength == -2) $:Z xb  
{ HOb\Hn|6jq  
System.err.println("File is not access!"); Z i&X ,K~  
} d0E5;3tQ  
else ED&KJnquWJ  
{ Nx z ,/d  
for(int i=0;i<nStartPos.length;i++) O4mWsr  
{ vAxtN RS  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); aKr4E3`  
} [c )\?MWW  
for(int i=0;i<nEndPos.length-1;i++) :8T@96]P  
{ G=Bj1ss.  
nEndPos = nStartPos[i+1]; Y %8QFM  
} vG:,oB}  
nEndPos[nEndPos.length-1] = nFileLength; v3#47F)  
} vjS7nR"T  
} g&5VorGx  
tvCTC ey  
8#-}3~l[  
//启动子线程 ,W;8!n0  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; WLFzLW=PD  
for(int i=0;i<nStartPos.length;i++) 'Q,<_ L"  
{ 1&nrZG9  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), nwH|Hs riU  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), wj~8KHan  
nStartPos,nEndPos,i); f 2f $aZ  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); jZ yh   
fileSplitterFetch.start(); Z6pDQ^Ii  
}  /t P  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 36UW oo  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Yb/^Qk59  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ^>uGbhBp  
nEndPos = " + nFileLength); C.p*mO&N  
// fileSplitterFetch[nPos.length-1].start(); w=2 X[V}  
Hb4rpAeP  
(b!DJ;(O9  
//等待子线程结束 BtZm_SeA  
//int count = 0; -ZJ:<  
//是否结束while循环 gRSG[GMV  
boolean breakWhile = false; H-lRgJdc  
\/zS@fz  
B)*%d7=x  
while(!bStop) NYRNop( N#  
{ Os+ =}  
write_nPos(); 1-<Xi-=^{t  
Utility.sleep(500); qILr+zH  
breakWhile = true; #}?$mxME*  
F@3,>~[%I  
f}3bYF  
for(int i=0;i<nStartPos.length;i++) (avaTUMOqy  
{ GrIdQi^8  
if(!fileSplitterFetch.bDownOver) FA,CBn5%  
{ " WL  
breakWhile = false; ),|bP`V  
break; IC~D?c0H:  
} ${3OQG  
} hw2Hn   
if(breakWhile) r?*?iw2g  
break; -n-X/M  
E ..[F<5  
g`8|jg0]`I  
//count++; SNFz#*  
//if(count>4) beoMLHp  
// siteStop(); so?1lG  
} `dhK$jYD  
h#9)M  
dRmTE  
System.err.println("文件下载结束!"); yKJp37R  
} p6*D^-  
catch(Exception e){e.printStackTrace ();} l71\II  
} C:cu1Y9  
 t&]IgF  
%yVZ|d*Q  
//获得文件长度 = %m/  
public long getFileSize() ;2}Gqh)Yr  
{ 2"T&Fp<  
int nFileLength = -1; L3\{{QOA  
try{ n\4+xZr  
URL url = new URL(siteInfoBean.getSSiteURL()); AS;{{^mM(  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ~XRr }z_Lq  
httpConnection.setRequestProperty("User-Agent","NetFox"); d=XhOC$  
|@nXlZE  
#.RI9B  
int responseCode=httpConnection.getResponseCode(); AF}HS8eYy  
if(responseCode>=400) ~x+w@4)a>  
{ (;3jmdJhK  
processErrorCode(responseCode); 1GxYuTZ{  
return -2; //-2 represent access is error 49 D*U5o  
} B~IOM  
wv$=0zF  
%;S5_K,  
String sHeader; gg9W7%t/  
}sZ]SE  
-XBNtM_ "  
for(int i=1;;i++) l=yO]a\QZ  
{ ADDpm-]  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); as8<c4:v  
//Utility.log(in.readLine()); 2},}R'aR  
sHeader=httpConnection.getHeaderFieldKey(i); s_N!6$tS   
if(sHeader!=null) 0=iJT4IEJ  
{  W~4|Z=f  
if(sHeader.equals("Content-Length")) sQvEUqy9  
{ KqQrxi?f-  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ^B/{  
break; rRW&29A  
} &wfM:a/c  
} \wd~ Y  
else .:0nK bW  
break; Z3d&I]Tf  
} f]4gDmn^  
} h) rHf3:  
catch(IOException e){e.printStackTrace ();} aw`mB,5U  
catch(Exception e){e.printStackTrace ();} sC j3h  
-T>`PJpJuL  
K67x.PZ  
Utility.log(nFileLength); Onl:eG;@  
LYKepk  
sf LBi~*j  
return nFileLength; UcZ3v]$I  
} 'D bHXS7N  
LQe<mZ<  
]=/f`  
//保存下载信息(文件指针位置) Yr!3mU-Uvt  
private void write_nPos() p0/I}n4<5n  
{ 4%p vw;r  
try{ *\>7@r[%5  
output = new DataOutputStream(new FileOutputStream(tmpFile)); b4Z#]o  
output.writeInt(nStartPos.length); 2yNlQP8%  
for(int i=0;i<nStartPos.length;i++) Qk6FK]buV  
{ x>Kem$z  
// output.writeLong(nPos); ,SBL~JJ  
output.writeLong(fileSplitterFetch.nStartPos); &lD4-_2J  
output.writeLong(fileSplitterFetch.nEndPos); @`3)?J[w  
} '=r.rW5  
output.close(); !tVV +vT#  
} 7]Z*]GRX  
catch(IOException e){e.printStackTrace ();} 4-o$OI>  
catch(Exception e){e.printStackTrace ();} rpd3Rp  
} 22GtTENd1h  
X*b0qJ Z  
"371`!%  
//读取保存的下载信息(文件指针位置) &EMm<(.]a  
private void read_nPos() sU>*S$X8  
{ i9\Pks#l%  
try{ w/R^Vwq  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 2c}kiqi{  
int nCount = input.readInt(); #M:W?&.  
nStartPos = new long[nCount]; ^E9@L ??  
nEndPos = new long[nCount]; jN[Z mJz'  
for(int i=0;i<nStartPos.length;i++) nQ mkDPjU  
{ kn! J`"b  
nStartPos = input.readLong(); OIN]u{S  
nEndPos = input.readLong(); (GZm+?  
} u3q!te  
input.close(); 7 >.^GD  
}  tW,<Pe  
catch(IOException e){e.printStackTrace ();} TGg*(6'z  
catch(Exception e){e.printStackTrace ();} ZnQnv@{8 l  
} 6Cibc .vt  
dM QnN[d6  
6ik6JL$AI  
private void processErrorCode(int nErrorCode)  9TeDLp  
{ &Z9b&P  
System.err.println("Error Code : " + nErrorCode); iVFn t!  
} 7|2:;5:U  
$T1c{T6n}  
#pf}q+A  
//停止文件下载 hM;EUWv  
public void siteStop() 0^;{b^!(  
{ S>6APQ-   
bStop = true; ohwQ%NDl  
for(int i=0;i<nStartPos.length;i++) @x)z" )>  
fileSplitterFetch.splitterStop(); :`_wy-}V  
mCg5-E~;  
'0[l'Dt'  
} |/q*Fg[f  
} ,7eN m>$  
//负责部分文件的抓取 a+MC[aFr  
**FileSplitterFetch.java }!2|*Y  
*/ L,R9jMx?_  
package NetFox; bO-8<IjC_3  
==$Ox6.  
_ yU e2Gd  
import java.io.*; l9n 8v\8,o  
import java.net.*; &We'omq  
R(csJ4F  
B-o"Y'iXs  
public class FileSplitterFetch extends Thread { #x'C  
xe 6x!  
sO6+L #!  
String sURL; //File URL pnf3YuB  
long nStartPos; //File Snippet Start Position }=wSfr9g  
long nEndPos; //File Snippet End Position :^l`m9  
int nThreadID; //Thread's ID 0^hz1\g  
boolean bDownOver = false; //Downing is over ?Hq`*I?b9  
boolean bStop = false; //Stop identical 3B>!9:w~f  
FileAccessI fileAccessI = null; //File Access interface 6MZfoR  
[3j]r{0I  
iE$0-Qe[3  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException $)kIYM&  
{ J)*y1   
this.sURL = sURL; w^dB1Y7c(W  
this.nStartPos = nStart; x *(pr5k  
this.nEndPos = nEnd; z]tvy).  
nThreadID = id; K2NnA  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 .NZ_dz$c  
} W(EU*~<UC  
n}a# b%e  
(xq25;|Y  
public void run() YckexfL  
{ N-lXC"{)  
while(nStartPos < nEndPos && !bStop) 8^+Q n/b_%  
{ {<&x9<f9  
T?Gi;ld7  
9erTb?@S  
try{ jMgNi@  
URL url = new URL(sURL); O75ioO0  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); D*heYh  
httpConnection.setRequestProperty("User-Agent","NetFox"); { R&F_51)V  
String sProperty = "bytes="+nStartPos+"-"; e -x{7  
httpConnection.setRequestProperty("RANGE",sProperty); V[CS{Hy'  
Utility.log(sProperty); he 9qWL&^G  
{DAwkJvb]  
Rg+V;C C~  
InputStream input = httpConnection.getInputStream(); AM,@BnEcuT  
//logResponseHead(httpConnection); &EZ28k"x  
TqCzpf&&h/  
CI ~+(+q  
byte[] b = new byte[1024]; 7(ZI]<  
int nRead; N9_9{M{  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) s}UPe)Vu  
{ 2g|+*.*`  
nStartPos += fileAccessI.write(b,0,nRead); 4_)@Nq  
//if(nThreadID == 1) jwGd*8 /  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Ws'3*HAce  
} "c=\?   
!i0:1{.  
aZ- )w  
Utility.log("Thread " + nThreadID + " is over!"); zPZy#7/A  
bDownOver = true; _epi[zf@  
//nPos = fileAccessI.write (b,0,nRead); -S Z^;t  
} ^?w6  
catch(Exception e){e.printStackTrace ();} yG{'hx6H  
} >|mmJ4T  
} .z)&#2E  
^\J/l\n  
E2 #XXc  
//打印回应的头信息 XP~4jOL]  
public void logResponseHead(HttpURLConnection con) s:,BcVLx^  
{ ;IE|XR(  
for(int i=1;;i++) NmVc2V]I  
{ mam|aRzd  
String header=con.getHeaderFieldKey(i); R 8?Xz5  
if(header!=null) NgQ {'H[Y  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); OV^) N  
Utility.log(header+" : "+con.getHeaderField(header)); t d-EB&i\  
else V]<J^m8  
break; @<r  ;>G  
} L:j;;9Sp{  
}  E*i <P  
AI/xOd!a  
9Iy>oV  
public void splitterStop() h{qB\aK  
{ BPwFcT)i!(  
bStop = true; 6xvyhg#B  
} 44]/rP_m  
9^x'x@6  
&qF   
} e%u1O -*  
WR%x4\,d#  
0Evq</  
/* fMP$o3;  
**FileAccess.java -}4<P}.5T  
*//文件访问(定位,写) K9 :I8E<  
package NetFox; hZU @35~BN  
import java.io.*; =T|Z[/fto  
H<Ed"-n$I<  
R6ca;  
public class FileAccessI implements Serializable{ ~f;d3dJ]/  
$x)C_WZj?  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 v=RQ"iv8  
RandomAccessFile oSavedFile; ^dM,K p  
long nPos; zkA"2dh  
;n?H/(6X8>  
|Rf4^vN  
public FileAccessI() throws IOException $&OoxC  
{ 2 <y!3OeN  
this("",0); ]KBzuz%  
} (ylpH`  
)u7y.o  
OjcxD5"v9  
public FileAccessI(String sName,long nPos) throws IOException ckHHD|  
{ h}nceH0s3d  
oSavedFile = new RandomAccessFile(sName,"rw"); VK5|w:  
this.nPos = nPos; 9|jk=`4UK  
oSavedFile.seek(nPos); Z ^zUb  
} 0sD"Hu  
[yF>W$Bn%  
ep>*]'  
public synchronized int write(byte[] b,int nStart,int nLen) 7`9J.L&,;  
{ WyF1Fw  
int n = -1; /=).)<&|R  
try{ }lvD 5  
oSavedFile.write(b,nStart,nLen); G];5'd~C;d  
n = nLen; xPl+ rsU  
} =$`EB  
catch(IOException e) :<=A1>&8  
{ U ]Ek 5p  
e.printStackTrace (); eZ'J,;  
} !yI , ~`Z  
NifzZEX  
]>M{Q n*  
return n; tsaf|xe  
} ^rO3B?_  
5ztHar~f  
'Y Bz?l9  
} |gxT-ZM  
Yw&{.<sL  
,HO~NqmB4  
/* Z/n\Ak sE  
**SiteInfoBean.java 7O84R^!|2  
*/ Q ;V `  
package NetFox; v1*Lf/  
Lf`LFPKb  
35|F?Jx.r  
public class SiteInfoBean { !$ItBn/_  
}d?"i@[  
yhhW4rz  
private String sSiteURL; //Site's URL 4=^_ 4o2  
private String sFilePath; //Saved File's Path zGjf7VV2a  
private String sFileName; //Saved File's Name 3\j{*f$J  
private int nSplitter; //Count of Splited Downloading File k GR5!8$z  
>|1.Z'r/  
mltG4R ?  
public SiteInfoBean() 0n` 1GU)W  
{//nSplitter的缺省值为5 )GhMM  
//default value of nSplitter is 5 nG hFYQl  
this("","","",5); vs]#?3+  
} _1 TSt%L  
sq1Z;l31"  
k<x  %  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) fbgq+f`\  
{ c 4xh  
sSiteURL= sURL; g b:)t }|  
sFilePath = sPath; >T: Yp<  
sFileName = sName; %P05k  
this.nSplitter = nSpiltter; iU]py  
s wgn( -  
G$FNofQx  
} i]oSVXx4WC  
QbA+\  
)xwWig.  
public String getSSiteURL() ?|Y/&/;%I  
{ f7NK0kuA  
return sSiteURL; =23JE'^=  
} unn2MP'  
\@6P A  
_o'_ z ]  
public void setSSiteURL(String value) QhV!%}7  
{ zfAHE {c  
sSiteURL = value; 0`y;[qAG[  
} yf5X=f.%@  
)Nv$ SH  
B^`'2$3  
public String getSFilePath() jF4h/((|EU  
{ H]>b<Cs  
return sFilePath; z@5t7e)!R  
} woIcW  
0=  ]RG  
U6SgV 8  
public void setSFilePath(String value) 57W4E{A  
{ mqPV Eo  
sFilePath = value; e}e|??'(\  
} E07g^y"}i  
V-rzn171Q)  
'fB/6[bd  
public String getSFileName() R?bF b|5t  
{ GjF'03Z4  
return sFileName; HivmKn`  
} KFxy,Z$-4  
v}w=I}<x  
U-+%e:v  
public void setSFileName(String value) haj\Dm  
{ v"x{oD$R  
sFileName = value; ;533;(d* o  
} j(JUOief  
D4jf%7X!Lu  
PP{2{  
public int getNSplitter() ~xz3- a/  
{ O}VI8OB(&  
return nSplitter; 5G-)>  
} )'\pa2  
%*4Gx +b  
w783e  
public void setNSplitter(int nCount) OG}auM4  
{ cQj{[Wt4  
nSplitter = nCount; '&~A  
} sR%,l  
} 8'c_&\kdv  
-4:L[.2  
=l%"Om*A  
/* ZT@a2:&  
**Utility.java "b6ZAgxv  
*/ VeT\I.K[  
package NetFox; 5$SO  
iM'{,~8R5  
{UX[SAQ  
public class Utility { TM sEHd  
r +X%0@K  
5tyr$P! N  
public Utility() :{pJ  
{ i7^_y3dG  
7=jeq|&kN  
b.jxkx\nt  
} ,XmTKO c  
NNUm=g^  
//线程睡眠 G[U'-a}I  
public static void sleep(int nSecond) Vj.5b0/(  
{ y~jKytq^@  
try{ ((Bu Bu>  
Thread.sleep(nSecond); Y)% CxaO `  
} [[fhfV+H  
catch(Exception e) K<`"Sr  
{ FBfyW- 7  
e.printStackTrace (); (+g!~MP  
} ]@@3]  
} 7.O1 ~-  
qGS]2KY  
//日志 | ?Js)i  
public static void log(String sMsg) (^h47kY  
{ B@w Q [  
System.err.println(sMsg); ;D5B$ @W>  
} J('p'SlI  
muSQFIvt  
R!7emc0T  
public static void log(int sMsg) wg?:jK  
{ V+A1O k )  
System.err.println(sMsg); "Q*Z?6[Z  
} hM*T{|y  
} L@rKG~{Xy  
aO@zeKg  
)9@I7QG?  
/* oh{!u!L`]  
**TestMethod.java z_XI,u}  
*/ !/0XoIf"  
package NetFox; G6X  
m9^ ? p  
 5" U8|  
public class TestMethod { ^0t81,`  
7QiJ1P.z  
% ~%>3  
public TestMethod() H9)$ #r6i  
{ ///xx/weblogic60b2_win.exe +nKxSjqI  
try{ A{hwT,zV:  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Gq5)>'D?  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); >M7e'}0 ;  
SiteFileFetch fileFetch = new SiteFileFetch(bean); u(KeS`  
fileFetch.start(); i,/|H]Mzr  
} KZV$rJ%G  
catch(Exception e){e.printStackTrace ();} ZgO7W]Z4  
-0| '{  
;FYiXK%  
} luZqW`?Bt  
Yyl2J#$!  
VHsNz WI  
public static void main(String[] args) %^RlE@l9  
{ ;8sEE?C$g  
new TestMethod(); o?P(Fuf  
} Fs:l"5~>1  
} WU1 I>i  
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