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http断点续传简单实现(java)

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/* +  ZR(  
**SiteFileFetch.java L.09\1?.n  
*/ M^j<J0(O  
package NetFox; /S7+B ]  
import java.io.*; ;[{:'^n  
import java.net.*; n_""M:XH  
F5N>Uqr*oN  
[2GXAvXsT  
public class SiteFileFetch extends Thread { qDby!^ryc  
.9T.3yQ  
j~,h )C/ v  
SiteInfoBean siteInfoBean = null; //文件信息Bean 94T}iY.  
long[] nStartPos; //开始位置 ]j& FbP)3  
long[] nEndPos; //结束位置 m >]>$=%  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ? .c?Pu  
long nFileLength; //文件长度 6#E]zmXO2  
boolean bFirst = true; //是否第一次取文件 La`h$=#`  
boolean bStop = false; //停止标志 >Hdjsu5{N  
File tmpFile; //文件下载的临时信息 5a=nF9/  
DataOutputStream output; //输出到文件的输出流 reJ"r<2  
N=>- Q)  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) q<-%L1kc 1  
public SiteFileFetch(SiteInfoBean bean) throws IOException ?Wwh _TO  
{ s{yJ:WncI  
siteInfoBean = bean; NNwc!x)*  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); jmkRP"ZnA  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); q&u$0XmV  
if(tmpFile.exists ()) (l Lu?NpIi  
{ riID,aut  
bFirst = false; N1PECLS?  
read_nPos(); ?K0U3V$s  
} fk+1#7{  
else BRe{1i 6  
{ ppEJs  
nStartPos = new long[bean.getNSplitter()]; a lrt*V|=  
nEndPos = new long[bean.getNSplitter()]; }.'Z =yy  
} TW>?h=.z  
mj)PLZ]  
WS5A Y @(~  
Ru:n~77{  
} 3a'q`.L  
Lj4&_b9  
pqJ)G;%9  
public void run() X&s7% ]n+  
{ kg:l:C)Tq  
//获得文件长度 M^uU4My  
//分割文件 zyDZ$Dhka  
//实例FileSplitterFetch SWT:frki`  
//启动FileSplitterFetch线程 )i @1X H"D  
//等待子线程返回 ?!H)zz6y  
try{ Ee8--  
if(bFirst) 3x![ 8 x  
{ }hCaNQ&jH  
nFileLength = getFileSize(); Bq *[c=(2  
if(nFileLength == -1) PT+c&5AS  
{ R3?:\d{  
System.err.println("File Length is not known!"); 6%%PP8.F  
} [yC"el6PM  
else if(nFileLength == -2) q@%h^9.  
{ iOll WkF  
System.err.println("File is not access!"); & N;pH  
} l&3ki!  
else ?I\v0H*  
{ Y#`Lcg+r,  
for(int i=0;i<nStartPos.length;i++) 8[~~gYl  
{ R4SxFp  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 7 W{~f?Sh  
} x<s|vgl|  
for(int i=0;i<nEndPos.length-1;i++) n$YE !D'  
{ -E]Sk&4Gj  
nEndPos = nStartPos[i+1]; /VO^5Dnb  
} 5q Rc4d'  
nEndPos[nEndPos.length-1] = nFileLength; <BPRV> 0X  
} ]~8v^A7u  
} ]`d2_mu  
88g47>{X  
(]XbPW  
//启动子线程 ?q!FG(  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; b=1%pX_  
for(int i=0;i<nStartPos.length;i++) [O_^MA,z  
{ <s}|ZnGE   
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), sT`^ljp4  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 7)J6/('  
nStartPos,nEndPos,i); q^*6C[G B  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ej52AK7  
fileSplitterFetch.start(); <0 uOq  
} Me/\z^pF  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ^=0 $  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); C(o.Cy6  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ],[)uTZc  
nEndPos = " + nFileLength); G52Z)^  
// fileSplitterFetch[nPos.length-1].start(); MCU9O  
[N:BM% FQ  
<GF@L  
//等待子线程结束 k|FSz#Y  
//int count = 0; >'`Sf ?+|  
//是否结束while循环 .GCR!V  
boolean breakWhile = false; _faJB@a_  
:#$F)]y'\  
[M:S`{SbY  
while(!bStop) ooE{V*Ie  
{ y94kX:q  
write_nPos(); eOnT W4  
Utility.sleep(500); \H4U8)l  
breakWhile = true; >SDp uG&>  
l}}UFEA^  
vT7g<  
for(int i=0;i<nStartPos.length;i++) [w+Q^\%bN  
{ EzwF`3RjK  
if(!fileSplitterFetch.bDownOver)  &s_}u%iC  
{ 72% {Wh/  
breakWhile = false; eq7C]i rH  
break; W>UjUq);  
} ">0 /8]l  
} +._f.BRmX.  
if(breakWhile) $::51#^Wg  
break; y0lLFe~  
SlM>";C\  
)E_!rR  
//count++; 3<yCe%I:  
//if(count>4) %,h!: Ec^c  
// siteStop(); A89Y;_4y  
} :Fq2x_IUE  
ei(| 5h  
R#r h  
System.err.println("文件下载结束!"); \Gv-sA  
} /<G yg7o0  
catch(Exception e){e.printStackTrace ();} 4j2~"K  
} U Ek |8yq  
7UY('Q[  
pyGFDB5_P  
//获得文件长度 nau~i1  
public long getFileSize() 8yNRx iW:  
{ 3ytx"=B%  
int nFileLength = -1; %!1@aL]pQ  
try{ ]M02>=1  
URL url = new URL(siteInfoBean.getSSiteURL()); )[F46?$vrk  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); jLpgWt`8)E  
httpConnection.setRequestProperty("User-Agent","NetFox"); xUV_2n+  
gogl[gHO  
U!3uaz'  
int responseCode=httpConnection.getResponseCode(); &^"s=g.  
if(responseCode>=400) jKe$&.q@  
{ >:(6{}b  
processErrorCode(responseCode); =Td#2V;0  
return -2; //-2 represent access is error #h}IUR  
} OpbszSl"y  
Jc9@VxWY  
iGpK\oH  
String sHeader; W` 6"!V  
y81#UD9[  
6tCV{pgm  
for(int i=1;;i++) xV }:M  
{ Wl@0TUK  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); S S7D1  
//Utility.log(in.readLine()); x|P<F2L  
sHeader=httpConnection.getHeaderFieldKey(i); |sDG>Zq?  
if(sHeader!=null) n:{-Vvt  
{ .je~qo )  
if(sHeader.equals("Content-Length")) 5+#?7J1  
{ 10a=YG  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); =2GP^vh  
break; T% jjs  
} e%5'(V-y,  
} \ZmFH8=|f  
else S0X.8Bq  
break; ^$T!@ +:  
} .F=<r-0  
} MC[ `<W)u  
catch(IOException e){e.printStackTrace ();} H-PW(  
catch(Exception e){e.printStackTrace ();} wjw<@A9  
l=<F1Lz  
R  oF  
Utility.log(nFileLength); v{\n^|=])  
Es ZnGuY  
iLI.e rm  
return nFileLength; 1GyAQHx,  
} K%.YNVHHC  
xOX*=Wv  
(PE8H~d  
//保存下载信息(文件指针位置) V8|q"UX  
private void write_nPos() 3z{5c   
{ &,6y(-  
try{ t8a@L(J$  
output = new DataOutputStream(new FileOutputStream(tmpFile)); P*nT\B  
output.writeInt(nStartPos.length); @pEO@bbg>  
for(int i=0;i<nStartPos.length;i++) EzeDShN=J  
{ 9cx!N,R t  
// output.writeLong(nPos); GwU>o:g"  
output.writeLong(fileSplitterFetch.nStartPos); vb80J<4  
output.writeLong(fileSplitterFetch.nEndPos); b*F :l#  
} AU${0#WV_  
output.close(); /oix tO)  
} C$Hl`>?$  
catch(IOException e){e.printStackTrace ();} F"HI>t)>  
catch(Exception e){e.printStackTrace ();} 0'`8HP  
} iM Y0xf8l  
u" NIG  
)b:~kuHi  
//读取保存的下载信息(文件指针位置) bl!f5ROS(  
private void read_nPos() GhfUCW%  
{ u3v6$CD?  
try{ `mHOgS>|  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Z ^9{Qq  
int nCount = input.readInt(); DRFuvU+e  
nStartPos = new long[nCount]; JCU3\39}  
nEndPos = new long[nCount]; "gl:4|i '  
for(int i=0;i<nStartPos.length;i++) GwIfGixqH  
{ JWm^RQ  
nStartPos = input.readLong(); @{$Cv"6769  
nEndPos = input.readLong(); r>:7${pF  
} M& BM,~  
input.close(); ~jCpL@rS  
} 8BoT%kVeJv  
catch(IOException e){e.printStackTrace ();} p'w"V6k('~  
catch(Exception e){e.printStackTrace ();} U!-+v:SF  
} "3>*i!i  
?H86Wbz  
%F]9^C+  
private void processErrorCode(int nErrorCode) :,z3 :PL  
{ <[B[  
System.err.println("Error Code : " + nErrorCode); tP^mq>  
} p31rhe   
$CYpO}u#  
Wj{Rp{}3  
//停止文件下载 i,b7Ft:F&  
public void siteStop() pN f9  
{ [+cnx21{  
bStop = true; ~FCSq:_  
for(int i=0;i<nStartPos.length;i++) ZT6X4 Z  
fileSplitterFetch.splitterStop(); s2v#evI`+  
sq (063l  
en#g<on  
} )PoI~km  
} Wv*BwiQ  
//负责部分文件的抓取 $^D(%  
**FileSplitterFetch.java (>5VS  
*/  yLIj4bf  
package NetFox; :AcN b  
VOK$;s'9}  
YU0HySP:  
import java.io.*; '<W,-i  
import java.net.*; HF=C8ZtlL  
1*, ~1!>  
EKS<s82hF&  
public class FileSplitterFetch extends Thread { W yJfF=<  
A =[f>8  
96E7hp !:  
String sURL; //File URL o/[yA3^  
long nStartPos; //File Snippet Start Position wj5s5dH  
long nEndPos; //File Snippet End Position T]Td4T!  
int nThreadID; //Thread's ID qsRfG~Cg  
boolean bDownOver = false; //Downing is over .q[sk  
boolean bStop = false; //Stop identical pz6- hi7  
FileAccessI fileAccessI = null; //File Access interface =|&"/$+s  
A_*Lo6uII  
9n\#s~,  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException -/7=\kao%  
{ oYm{I ~"  
this.sURL = sURL; \V- Y,!~5  
this.nStartPos = nStart; it|:P  
this.nEndPos = nEnd; e^Wv*OD'  
nThreadID = id; .O-DVW Cm  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 9X&qdA/q  
} e`2R{H  
-V_S4|>   
SR8Kzk{  
public void run() #2'&=?J1r  
{ E=~WQ13Q  
while(nStartPos < nEndPos && !bStop) 4k?JxA)  
{ `lh?Z3W  
K]*ERAfM%m  
!J(,M)p!  
try{ L , Fso./y  
URL url = new URL(sURL); 2u H\8A+'f  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); [_G0kiI}W"  
httpConnection.setRequestProperty("User-Agent","NetFox"); VP[!ji9P   
String sProperty = "bytes="+nStartPos+"-"; 5$Q`P',*Ua  
httpConnection.setRequestProperty("RANGE",sProperty); %c2i.E/G  
Utility.log(sProperty); " /-v 9  
VRP.tD  
[>9"RzEl  
InputStream input = httpConnection.getInputStream(); !4.^@^L|\  
//logResponseHead(httpConnection); "8dnFrE  
(s*Uz3 sq  
5)NfZN# &  
byte[] b = new byte[1024];  y] r~v  
int nRead; <).qe Z  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 'R5l =Wf  
{ nln[V$   
nStartPos += fileAccessI.write(b,0,nRead); HZ4 ^T7G  
//if(nThreadID == 1) I[IQFka}  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 959jp85  
} 0(f;am0y  
!e"m*S.(6{  
ZoReyY2  
Utility.log("Thread " + nThreadID + " is over!"); PCnJ2  
bDownOver = true; 3evfX[V#  
//nPos = fileAccessI.write (b,0,nRead); \gv x)S11  
} wTbIS~!gF  
catch(Exception e){e.printStackTrace ();} VOOThdR  
} *!s?hHv  
} OWfj<#}t+  
`;2`H, G'  
uQ+$HzxX  
//打印回应的头信息 leJd) {  
public void logResponseHead(HttpURLConnection con) ]h$TgX  
{ p5t#d)  
for(int i=1;;i++) X_8NW,  
{ /UyE- "S  
String header=con.getHeaderFieldKey(i); h;[Nc j]  
if(header!=null) T=Q{K|JE  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); $oj<yH<i  
Utility.log(header+" : "+con.getHeaderField(header)); D];([:+4  
else L(S.  
break; ^P`'qfZ  
} =B%e0M  
}  Jl,x~d  
XKIJ6M~5k  
8?pZZtad  
public void splitterStop() hIr^"kVK  
{ ~Nh7C b _  
bStop = true; rrRC5h  
} "evV/Fg (  
&" n9,$  
;KN@v5`p  
} 3_/d=ZI\  
E zUjt)wF  
ka [NYW{.  
/* P*sCrGO%  
**FileAccess.java Sd11ZC6  
*//文件访问(定位,写) sxa (  
package NetFox; {Vu:yh\<  
import java.io.*; t4uxon  
8#B;nyGD1I  
m q9&To!  
public class FileAccessI implements Serializable{ n8,/olqwW  
QV1%Zou  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 [}3Y1t{G  
RandomAccessFile oSavedFile; ^Tmmx_Xw  
long nPos; 6 nhB1Aei  
8;rS"!qM  
{4*%\?c,n  
public FileAccessI() throws IOException Pw.+DA  
{ /RJSkF+!  
this("",0); \ziF(xTvqG  
}  JwcP[w2  
!1R  
<{uIB;P  
public FileAccessI(String sName,long nPos) throws IOException mj~CCokF{?  
{ 5P x_vtqP  
oSavedFile = new RandomAccessFile(sName,"rw"); TUr}p aw_  
this.nPos = nPos; yRDLg c  
oSavedFile.seek(nPos); VvKH]>*  
} `#U6`[[  
K)OlCpHc  
9hU@VPB~  
public synchronized int write(byte[] b,int nStart,int nLen) =h{2!Ah7 X  
{ H\vO0 <X  
int n = -1; 5H2|:GzUc  
try{ )G&OX  
oSavedFile.write(b,nStart,nLen); V" 73^  
n = nLen; *^ BE1-  
} yD"sYT   
catch(IOException e) 1<5yG7SZ  
{ f^ qQ 5N  
e.printStackTrace (); =c'LG   
} A:Z:&(NtE:  
K.~U%v}  
5N/;'ySAE_  
return n; m\=u/Zip  
} gE~31:a^  
!5-[kG&  
XMdYted  
} 6D<A@DR9J  
!$HWUxM;p  
&D#v0!e~x  
/* `x{gF8GV  
**SiteInfoBean.java :1Cc~+]w(u  
*/ 6G],t)<A'-  
package NetFox; oGZ9@Y)(T  
DS fKUx&  
\ZB;K~BV&  
public class SiteInfoBean { pV8,b   
sEa:p: !  
H Vy^^$  
private String sSiteURL; //Site's URL 0a5P@;"a  
private String sFilePath; //Saved File's Path '`u1,h  
private String sFileName; //Saved File's Name IcZ'KV  
private int nSplitter; //Count of Splited Downloading File NR5A"_'  
+nuQC{^>  
V<7Gd8rDMM  
public SiteInfoBean() y:L|]p}huE  
{//nSplitter的缺省值为5 5I14"Qf  
//default value of nSplitter is 5 $.kYAsZts  
this("","","",5); gFH_^~7i8p  
} N>_7Ltw/  
<4Fd ~  
B$G8,3,:  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) P?F:x=@'|  
{ Zl)|x%z  
sSiteURL= sURL; 1N &U{#4  
sFilePath = sPath; U&NOf;h$  
sFileName = sName; Jz6PqU|=  
this.nSplitter = nSpiltter; `}bUf epMJ  
?l/rg6mbI'  
<~3 a aO  
} Cnolka"  
Jc+U$h4  
3^\y>  
public String getSSiteURL() Y'P8`$  
{ !Zrvko  
return sSiteURL; \ gN) GR  
} c?d#Bj ?  
TJ<PT  
1NTe@r!y  
public void setSSiteURL(String value) U7W ct %  
{ 6!$S1z#wM  
sSiteURL = value; M\%{!Wzo8  
} ocMf}"  
,#A,+!4  
) E\pQ5&  
public String getSFilePath() @l8?\^N  
{ 1#V0g Q  
return sFilePath; B.|vmq,u  
} d3\8BKp  
wcOAyo5(n  
$2.DZ  
public void setSFilePath(String value) 3 R m$  
{ AYi$LsLhO  
sFilePath = value; "YBA$ef$  
} _C4^J  
IO+z:D{  
/c7j@=0  
public String getSFileName() E*%{Nn  
{ k}/: xN"  
return sFileName; Pzqgg43Xf  
} Z`W.(gua  
;KhYh S(q  
-nW{$&5AF  
public void setSFileName(String value) lbPxZ'YO#  
{ 3"".kf,O5e  
sFileName = value; H Ow hl  
} _eF*8 /z  
~ 0[K%]]  
8WH>  
public int getNSplitter() KQqlM  
{ Zj JD@,j  
return nSplitter; %F7aFvl*  
} ^ey\ c1K  
WM#!X!Vo  
AIeYy-f  
public void setNSplitter(int nCount) Ub"\LUu  
{ 8c~H![2u  
nSplitter = nCount; @EQ{lGpU3  
} |LQmdgVr$  
} 9. R _=  
`>*P(yIN  
M_e! s}F  
/* IoX(Pa  
**Utility.java L/ZZe5I  
*/ #Ky0` n  
package NetFox; F,D &  
V$@2:@8mo  
T&c[m!}X|t  
public class Utility { 7+c@pEU]  
r'8e"pTi  
3S,pd0;  
public Utility() 5 xiYCOy  
{ y`N1I  
Z` Aiw."|  
(*EN!-/  
} H$;\TG@,  
ZpdM[\Q-  
//线程睡眠 =}L[/RL  
public static void sleep(int nSecond) z/TRqD  
{ BP7_o63/G  
try{  A=,m  
Thread.sleep(nSecond); YP6+o#==  
} V6!oe^a7'  
catch(Exception e) #qPk,a  
{ .B)v " Sw#  
e.printStackTrace (); ":Q70*xSm  
} us]ah~U6A  
} xj}N;FWo  
%!q(zql  
//日志 Yc %eTh  
public static void log(String sMsg) 4M:oa#gh@  
{ a}fW3+>  
System.err.println(sMsg); <sTa Xaq?  
} ;9^B# aTM  
0e:aeLh  
6(z.(eT  
public static void log(int sMsg) ^a(q7ZfY  
{ u]}Xq{ZN  
System.err.println(sMsg); 4uv }6&R  
} &O'yhAP] j  
} iCH Z{<k  
#*~ (  
d ] [E;$  
/* IL~yJx_11  
**TestMethod.java d<whb2l  
*/ V +hV&|=  
package NetFox; DQ~@=%?ni  
. v;Npm2  
.-r 1.'.A  
public class TestMethod { }vL[N~5\  
=?}'\ >G "  
-H]svOX  
public TestMethod() $Fn# b|e  
{ ///xx/weblogic60b2_win.exe H95VU"  
try{ hIdGQKr>V  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ,Pl[SMt!  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); A(C3kISM  
SiteFileFetch fileFetch = new SiteFileFetch(bean); |.,y M|  
fileFetch.start(); Fb_~{q  
} isaT0__8  
catch(Exception e){e.printStackTrace ();} :ortyCB:H  
2Zl65  
!~RD>N&n  
} bi_R.sfK&  
J/mLB7^R  
9|go`^*.  
public static void main(String[] args) /E*P0y~KTW  
{ xv)7-jlx  
new TestMethod(); 5?Bi+fg  
} fpzTv3D=I  
} L'c4 i[~s  
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