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http断点续传简单实现(java)

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/* RnkrI~x  
**SiteFileFetch.java j1,ir  
*/ n.xW"omN  
package NetFox; q>ps99[=  
import java.io.*; V`"A|Y  
import java.net.*; VSt)~  
X8b= z9  
F4Gv=q)Z  
public class SiteFileFetch extends Thread { O}#h^AU-BS  
13P8Zmco  
h=~ TgTv  
SiteInfoBean siteInfoBean = null; //文件信息Bean }%9A+w}o  
long[] nStartPos; //开始位置 j!P]xl0vOZ  
long[] nEndPos; //结束位置 * 7 o(  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 +O @0gl  
long nFileLength; //文件长度 _6 |lw&o07  
boolean bFirst = true; //是否第一次取文件 mMvt#+O  
boolean bStop = false; //停止标志 l;SqjkN  
File tmpFile; //文件下载的临时信息 q>*+.~  
DataOutputStream output; //输出到文件的输出流 ?8Hr 9  
5l"v:Px  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) xeX Pc7JG  
public SiteFileFetch(SiteInfoBean bean) throws IOException =X11x)]F9  
{ E(oI0*S.5  
siteInfoBean = bean; <k&Q"X:"  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); /-l7GswF  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); {\L /?#  
if(tmpFile.exists ()) k/yoRv%  
{ 8I'c83w  
bFirst = false; !(soMv  
read_nPos(); (P[:g  
} Y\ len  
else iy{*w&p  
{ :.IVf Zw  
nStartPos = new long[bean.getNSplitter()]; io$!z=W  
nEndPos = new long[bean.getNSplitter()]; XOzd{  
} 1#9Q1@'OS  
mh"&KX86W  
nxP>IfSA  
uFIr.U$V  
} d3AOuVUf  
D0D0=s  
#$QC2;/)F  
public void run() CCOd4  
{ bBBW7',[a  
//获得文件长度 D}wM$B@S  
//分割文件 A7|!&fi  
//实例FileSplitterFetch MS-}IHO  
//启动FileSplitterFetch线程  pojQ/  
//等待子线程返回  h+Dp<b  
try{ N246RV1W  
if(bFirst) NZSP*#!B  
{ `g&<7~\=A  
nFileLength = getFileSize(); ^9 gFW $]  
if(nFileLength == -1) Lf|5miO  
{ K%ltB&  
System.err.println("File Length is not known!"); TpLlbsd  
} r<38; a  
else if(nFileLength == -2) AXhV#nZt0  
{ pt&(c[  
System.err.println("File is not access!"); ixZ w;+h  
} Q=[A P+  
else 445}Yw5;9  
{ }U K<tUO  
for(int i=0;i<nStartPos.length;i++) r7r>1W%4  
{ V8w!yc  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); @bQf =N+  
} KPI c?|o/6  
for(int i=0;i<nEndPos.length-1;i++) {#aW")x^#  
{ ?r"'JO.w  
nEndPos = nStartPos[i+1]; 7{ zkqug  
} c0.i  
nEndPos[nEndPos.length-1] = nFileLength; $IzhaX  
} 48JD >=@7  
} 47b=>D8  
|[/[*hDZ9  
3VZeUOxY\W  
//启动子线程 PMzPe"3M  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; vs-%J 6}G  
for(int i=0;i<nStartPos.length;i++) S3rN]!B+  
{ x}t,v.:  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), kZXsL  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), u-g2*(ZT  
nStartPos,nEndPos,i); AvF:$ kG  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 7/nnl0u8  
fileSplitterFetch.start(); 8.4 1EKr2  
} WV]%llj^  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 4<b=;8  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); #jAlmxN  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", V3 j1M?>  
nEndPos = " + nFileLength); =~M%zdIXv  
// fileSplitterFetch[nPos.length-1].start(); CPssk,q~C  
<smi<syx  
-F.A1{l[.  
//等待子线程结束 kk_$j_0  
//int count = 0; k*)O]M<,  
//是否结束while循环 YY~BNQn6d  
boolean breakWhile = false; n#,<-Rb-  
g.![>?2$8  
&w@~@]  
while(!bStop) {=]1]IWt  
{ S}zh0`+d'Z  
write_nPos(); tEEeek(!  
Utility.sleep(500); x!$Dje}  
breakWhile = true; Z Z1s}TG  
2p3ep,  
~I^}'^Dbb  
for(int i=0;i<nStartPos.length;i++) jA ?tDAx`  
{ {4u8~whLp  
if(!fileSplitterFetch.bDownOver) E]x)Qr2Ju  
{ ofe SGx  
breakWhile = false; H` !%"  
break; 0fc]RkHs"  
} Efo,5  
} ppcuMcR{  
if(breakWhile) 0:K4,  
break; wFr}]<=Mi  
=\v./Q-  
,/ V'(\>  
//count++; ZSL:q%:.  
//if(count>4) /($!("b  
// siteStop(); 5fGUJ[F=  
} J7. }2  
F^iv1b  
,,+ ~./)  
System.err.println("文件下载结束!"); H]:z:AAvX  
} ~i)O^CKq  
catch(Exception e){e.printStackTrace ();} h'8w<n+%)  
} d\nBc6  
bI^zwK,@4  
?H9F"B$a  
//获得文件长度 Up|\&2_  
public long getFileSize() p{:r4!*L  
{ ,6[}qw) *  
int nFileLength = -1; f3h&K}x  
try{ ,WF)GS|7V  
URL url = new URL(siteInfoBean.getSSiteURL()); [ e4)"A"  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); )r O`K  
httpConnection.setRequestProperty("User-Agent","NetFox"); )2Gp3oD?  
Gmcx#?|Tx  
J90q\_dY.  
int responseCode=httpConnection.getResponseCode(); K7&A^$`  
if(responseCode>=400) W'{q  
{ 02]9 OnWw  
processErrorCode(responseCode); S fE^'G\  
return -2; //-2 represent access is error e=t?mDh#E  
} I>b-w;cC  
LX<c(i  
fTi,S)F'  
String sHeader; \~xOdqF/  
Y[8w0ve- g  
b~ ?TDm7  
for(int i=1;;i++) 5*1wQlL  
{ ~Z5?\a2Ld  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); %l@Q&)f8e  
//Utility.log(in.readLine()); ak50]KYo  
sHeader=httpConnection.getHeaderFieldKey(i); G)l[\6Dn  
if(sHeader!=null) &?3?8Q\  
{ r;w_B%9  
if(sHeader.equals("Content-Length")) v>Il #  
{ }+`W[h&u  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); x_Ki5~w5  
break; D%LM"p  
} iUh_rX9A"  
} =5&)^  
else S[UHx}.  
break; fiTMS:  
} yz-IZt(  
} S>7Zq5*  
catch(IOException e){e.printStackTrace ();} kP%W:4l0  
catch(Exception e){e.printStackTrace ();} @6GM)N\{[  
H<`[,t  
<9bQAyL9  
Utility.log(nFileLength); w;Qo9=-  
MAR kTxzi  
TMG:fg&E~  
return nFileLength; u*Oz1~  
} 5fb,-`m.  
&RXd1>|c2  
&tZ?%sr  
//保存下载信息(文件指针位置) 0[D5]mcv  
private void write_nPos() d8M"vd  
{ GT%V,OJ  
try{ %R;cXs4r  
output = new DataOutputStream(new FileOutputStream(tmpFile)); *D<S \6=  
output.writeInt(nStartPos.length); (W+9 u0Zq  
for(int i=0;i<nStartPos.length;i++) oAWk<B(@  
{ p%IR4f  
// output.writeLong(nPos); J+\F)k>r  
output.writeLong(fileSplitterFetch.nStartPos); YH<F~F _  
output.writeLong(fileSplitterFetch.nEndPos); 2xe_Q70II  
} w0SzK-&  
output.close(); K@n.$g  
} q~trn'X>  
catch(IOException e){e.printStackTrace ();} kRiWNEw  
catch(Exception e){e.printStackTrace ();} z9HQFRbo[  
} U]R?O5K  
zwU8iVDe  
%~p_bKd~  
//读取保存的下载信息(文件指针位置) @+1E|4L1vf  
private void read_nPos() 77i |a]Kd  
{ RMC|(Q<  
try{ zp4ru\  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 9,`mH0jP  
int nCount = input.readInt(); Y1k/ngH  
nStartPos = new long[nCount]; ]Jnf. 3  
nEndPos = new long[nCount]; &K>]!yn   
for(int i=0;i<nStartPos.length;i++) V"$t>pAG  
{ TP{a*ke^5,  
nStartPos = input.readLong(); puqLXDjA/  
nEndPos = input.readLong(); CHeG{l)<r  
} $+P v fQ  
input.close(); 2zFdKs,  
} $elrX-(vL  
catch(IOException e){e.printStackTrace ();} 1xguG7  
catch(Exception e){e.printStackTrace ();} 1 9 k$)m  
} M8[YW|VkP  
(X>y)V  
S OK2{xCG  
private void processErrorCode(int nErrorCode) rG\m]C3E  
{ !FSraW2  
System.err.println("Error Code : " + nErrorCode); fykN\b  
} k5/nAaiVE  
='VIbE@qC  
w:Lu  
//停止文件下载 h.?[1hT4R  
public void siteStop() Mxd fuFss  
{ BB%(!O4Dl  
bStop = true; w!}1oy  
for(int i=0;i<nStartPos.length;i++) Hl;p>>n  
fileSplitterFetch.splitterStop(); 'j_H{kQy  
DQ\&5ytP  
mM} Ukmy  
} (U_Q7hja?  
} Fnpn_O XlH  
//负责部分文件的抓取 N1~V +_mM  
**FileSplitterFetch.java F2$bUY  
*/ L"h@`3o|  
package NetFox; q#&#*6 )B  
`Kw"XGT  
7NB 9Vu|gD  
import java.io.*; c^Jgr(Ow  
import java.net.*; ~H|LWCU)K8  
{[5L96RH%  
KWJgW{{v  
public class FileSplitterFetch extends Thread { "&#W Mi  
%lJiM`a  
>&vO4L  
String sURL; //File URL {!1n5a3" 1  
long nStartPos; //File Snippet Start Position "QO/Jls  
long nEndPos; //File Snippet End Position 1Bk*G>CX9(  
int nThreadID; //Thread's ID pLQSG}N  
boolean bDownOver = false; //Downing is over IR dz(~CP  
boolean bStop = false; //Stop identical I?Jii8|W9  
FileAccessI fileAccessI = null; //File Access interface %HF$  
NhK(HTsvK  
tOM3Gs~o6z  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ]Ec[")"kT  
{ 9LEilmPs  
this.sURL = sURL; nqxq@.L2  
this.nStartPos = nStart; gQh Ccv  
this.nEndPos = nEnd; 5Ue^>8-  
nThreadID = id; U aj`  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 qi SEnRG.  
} R_Gq8t$  
%wjB)Mae  
an=+6lIl  
public void run() Hx2j=Q_dw  
{ 2b4pOM7W  
while(nStartPos < nEndPos && !bStop) OgXZ-<'  
{ sMfFm@\N  
A-7wkZ.H  
r$r&4d Y  
try{ *2Vp4  
URL url = new URL(sURL); '!fFI1s  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ^wO_b'@v  
httpConnection.setRequestProperty("User-Agent","NetFox"); 7c29Ua~[  
String sProperty = "bytes="+nStartPos+"-"; {"0TO|%x  
httpConnection.setRequestProperty("RANGE",sProperty); 1>@]@ST[:  
Utility.log(sProperty); g2aT`=&Z  
l<aqiZSY  
[)H,zpl  
InputStream input = httpConnection.getInputStream(); :nKsZ1bX  
//logResponseHead(httpConnection); 7/&C;"  
X&9^&U=e  
%%as>}.  
byte[] b = new byte[1024]; -y l4tW  
int nRead; FI`nRFq)C  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Q+N7:o!;<b  
{ EFRZ% Y  
nStartPos += fileAccessI.write(b,0,nRead); j$|j8?  
//if(nThreadID == 1) 8g[ (nxI~  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Pe$^Mo.q  
} C`2*2Y%xkG  
=M1a0i|d  
Iuu<2#gb8"  
Utility.log("Thread " + nThreadID + " is over!"); *#Lsjk~_-  
bDownOver = true; _@#uIOcE  
//nPos = fileAccessI.write (b,0,nRead); o\@ A2r3  
} >J^7}J  
catch(Exception e){e.printStackTrace ();} :$M9XZ~\  
} $ ] W[y=  
} U^[cYTG  
`P^u:  
DnNt@e2|  
//打印回应的头信息 @tr&R==([  
public void logResponseHead(HttpURLConnection con) &TP:yA[  
{ u8-a-k5<  
for(int i=1;;i++) J ?ztn  
{ .N5h V3  
String header=con.getHeaderFieldKey(i); [Krm .)  
if(header!=null) HF &h  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 5T$}Oy1  
Utility.log(header+" : "+con.getHeaderField(header)); ( oQ'4,F  
else ,] ~u:Y}  
break; OwG6i|q  
} G0I~&?nDa  
} vF9*tK'   
b4Ricm  
o,?!"*EP  
public void splitterStop() 94~"U5oQ:  
{ /^++As0pY  
bStop = true; x r-;,W  
} bK ?1MiXb  
dV5PhP>6  
A#v|@sul  
} e1^fUOS  
5~@?>)TBv  
t2=a(N-/,  
/* ^~ Ekg:`  
**FileAccess.java B3y?.  
*//文件访问(定位,写) 69t7=r  
package NetFox; u|(Ux~O  
import java.io.*; KKLR'w,A>  
i/NDWVFD  
7n\ThfH{  
public class FileAccessI implements Serializable{ 8 ne/=N|,  
}czsa_  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 !cRfZ  
RandomAccessFile oSavedFile; 9.xvV|Sp  
long nPos; *,"jF!C&[  
LMAmpVo  
j'3j}G%\T  
public FileAccessI() throws IOException 9 0X?1  
{ bRWIDPh  
this("",0); ?F ce!J  
} hdo&\Q2D8  
i][f#e4  
#X#8ynt  
public FileAccessI(String sName,long nPos) throws IOException EbCIIMbe"  
{ ]53O}sH>  
oSavedFile = new RandomAccessFile(sName,"rw"); y|^EGnaE  
this.nPos = nPos; F;#zN  
oSavedFile.seek(nPos); zm3-C%:Bw  
} Ffnk1/ Zy  
:d.1;st  
kB8 Mi  
public synchronized int write(byte[] b,int nStart,int nLen) Ski G2n]  
{ ndr)3tuYu  
int n = -1; H#+\nT2m  
try{ fb23J|"  
oSavedFile.write(b,nStart,nLen); ZI,j?i6\  
n = nLen; m d?b*  
}  }<=3W5+  
catch(IOException e) ?{eY\I  
{ Kv}k*A% S  
e.printStackTrace (); R\*)@[y9l  
} O16r!6=-n  
^00{Hd6  
dXl]Pe|v  
return n; UgR :qjI  
} '@bJlJB9>  
?mMW*ico  
E tx`K5Tr]  
} 1SUzzlRx  
X]!D;7^  
)|pU.K9qZ  
/* KnJx{8@z  
**SiteInfoBean.java _42Z={pZZq  
*/ DVh)w}v  
package NetFox; xdZ<| vMR  
+%XnMl  
}#6xFTH  
public class SiteInfoBean { d`Oe_<  
)Q]w6he3  
+Rqbf  
private String sSiteURL; //Site's URL BxdX WO  
private String sFilePath; //Saved File's Path UW6VHA>  
private String sFileName; //Saved File's Name  <B )   
private int nSplitter; //Count of Splited Downloading File Ux}W&K/?'  
=We2^W-{  
k][h9'  
public SiteInfoBean() < bFy(+  
{//nSplitter的缺省值为5 59 <hV?  
//default value of nSplitter is 5 tuLH}tkNY  
this("","","",5); ARF\fF|<2  
} X?/Lz;,&  
;7Okyj6EP  
jO8X:j09A  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) !n<o)DsZR  
{ ? %(spV  
sSiteURL= sURL; w2OsLi Sv  
sFilePath = sPath; VRbQdiZ{  
sFileName = sName; : @6mFTV  
this.nSplitter = nSpiltter; I\zemW!  
R0wf#%97  
AnMV <  
} RlRs}yF  
!E0!-UpY  
X>zlb$  
public String getSSiteURL() =6\LIbO  
{ ]Blf9h7  
return sSiteURL; f~ZEdq8  
} $a(`ve|  
#jA)>z\Q^  
S6sq#kcH  
public void setSSiteURL(String value) y=Q!-~5|fF  
{ |cd-!iJX-  
sSiteURL = value; ;>>C)c4V"  
} Qxa{UQh}9  
}k7'"`#?"  
~L{l+jK$p  
public String getSFilePath() q \O Ou  
{ "2{%JFE  
return sFilePath; fS=hpL6]@  
} jfp z`zE  
M%`\P\A  
I7(?;MpI  
public void setSFilePath(String value) 2@khSWV  
{ +Qj(B@ i  
sFilePath = value; |+}G|hx@9  
} gl7|H&&xV  
:a0zT#u  
uQ/h'v  
public String getSFileName() Q5a)}6-5  
{ ig+4S[L~n  
return sFileName; {whvTN1#dh  
} ~*.-  
:iUF7P1I  
09h.1/  
public void setSFileName(String value) L'Q<>{;Ig  
{ 1G^#q,%X_v  
sFileName = value; |E)aT#$f'  
} $}o b,i^W  
F0lOlS   
& ,hr8  
public int getNSplitter() *d*,Hqn  
{ I)SG wt-  
return nSplitter; @)6jE!LC  
} v]VWDT `  
6iA( o*'Yn  
19UN*g3(  
public void setNSplitter(int nCount) I5ZqBB  
{ kHK0(bYK  
nSplitter = nCount; Zjh2{ :  
} +&=?BC}L9^  
} [1yq{n=  
;2xO`[#  
N.do "  
/* z@ 35NZn  
**Utility.java 60>.ul2  
*/ *%5{'  
package NetFox; 6<76H  
/~p+j{0L3W  
mN_Z7n;^eh  
public class Utility { E%N2k|%8d_  
x.mrCJn)  
'@nbqM  
public Utility() {FO$yw=>  
{ Fr2N[\>s  
R:aa+MX(1  
RO(TvZ0pE  
} w?Ju5 5  
KvFMs\o6p  
//线程睡眠 xg@NQI@7   
public static void sleep(int nSecond) #KlCZ~s  
{ (qM j-l  
try{ $.%rAa_H  
Thread.sleep(nSecond); J9~i%hzr  
} iUk-'   
catch(Exception e) 3>M&D20Z  
{ ,5 j"ruZ  
e.printStackTrace (); @@G6p($  
} &DG->$&|  
} V N{NA+I  
!A3-0zN!  
//日志 lCd@jB{  
public static void log(String sMsg) OHr Y(I6  
{ 68fiG  
System.err.println(sMsg); bBcp9C)iY  
} <6TT)t<h  
>4` dy  
zw<p74DH  
public static void log(int sMsg) qFX~[h8i+  
{ B;6]NCx D  
System.err.println(sMsg); 2NGe C0=  
} ji1HV1S  
}  D1 Z{W  
8LkP)]4^sO  
EI~"L$?  
/* {~GYj%-^  
**TestMethod.java !`JHH&  
*/ AI vXb\wL  
package NetFox; $q?$]k|M`  
%q ;jVj[  
C;+(Zp  
public class TestMethod { fc=Patg  
&.13dq  
b3-e R5U/  
public TestMethod() `N//A}9  
{ ///xx/weblogic60b2_win.exe '7Nr8D4L  
try{ #m{{a]zm^  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); w.\w1:d  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); gbeghLP[?  
SiteFileFetch fileFetch = new SiteFileFetch(bean); `vG,}Pt]  
fileFetch.start(); x&Vm!,%:1  
} Jf)bHjC_V  
catch(Exception e){e.printStackTrace ();} rB~W Iu  
*_Z#O,  
k#Of]mXXz  
} qSqI7ptA\  
PP~rn fE  
kd:$oS_*s  
public static void main(String[] args) p9U?!L!y  
{ <$w?/y/'  
new TestMethod(); \I-#1M  
} n~V4nj&_T  
} "vYE+   
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