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http断点续传简单实现(java)

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/* i'57|;?  
**SiteFileFetch.java ,wFLOfV@  
*/ ~k J#IA  
package NetFox; jt]+(sx  
import java.io.*; Te.hXCFD  
import java.net.*; SZ0Zi\W  
5I<?HsK@  
F>}).qx  
public class SiteFileFetch extends Thread { tz)L`g/J~  
"2;UXX-H  
Im Tq`  
SiteInfoBean siteInfoBean = null; //文件信息Bean B]hZ4.B1  
long[] nStartPos; //开始位置 '6aH*B:}*;  
long[] nEndPos; //结束位置 8^~ljf]6  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 # ._!.P  
long nFileLength; //文件长度 ybB}|4d&   
boolean bFirst = true; //是否第一次取文件 Z>{8FzP.F  
boolean bStop = false; //停止标志 cg$~.ytPK  
File tmpFile; //文件下载的临时信息 C {'c_wX  
DataOutputStream output; //输出到文件的输出流  q)%C|  
/TB_4{  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) :4 ;>).  
public SiteFileFetch(SiteInfoBean bean) throws IOException g3 qtWS  
{ ^ ]B&7\w"t  
siteInfoBean = bean; 16] O^R;r  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); s$]I@;_  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); x:@e ID  
if(tmpFile.exists ()) 1'g?B`  
{ .N5"IY6>  
bFirst = false; -Rf|p(SJ,E  
read_nPos(); adxJA}K}  
} 5]F9o9]T  
else ?hwQY}   
{ C f+O7Y`^  
nStartPos = new long[bean.getNSplitter()]; q|j;dI&  
nEndPos = new long[bean.getNSplitter()]; @!F9}n AP  
} 7N""w5  
NeWssSje  
q=EQDHmh  
/bw-*  
} foN;Q1?lS  
't>Qj7vh0  
iCc \p2p  
public void run() *JDc1$H0  
{ 2/bck)p=  
//获得文件长度 U M#]olh  
//分割文件 B(>_.x#kv  
//实例FileSplitterFetch }??q{B@v  
//启动FileSplitterFetch线程 ~L1N1Z)Kk  
//等待子线程返回 p@^2 .O+  
try{ 0~-+5V  
if(bFirst) a'A0CQ  
{ x~(Ul\EX  
nFileLength = getFileSize(); U?}Maf  
if(nFileLength == -1) +wio:==  
{ ?Z.YJXoKZ  
System.err.println("File Length is not known!"); JlH|=nIaj6  
} XM)|v |  
else if(nFileLength == -2) ,CvU#ab8$  
{ 5Q^~Z},  
System.err.println("File is not access!"); &"CS1P|  
} ck^Z,AKL+  
else 6Z'zB&hM}  
{ p;'vOb  
for(int i=0;i<nStartPos.length;i++) nU`;MW/^w  
{ >U}~Hv]  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); `C=p7 %  
} m+!%+S1  
for(int i=0;i<nEndPos.length-1;i++) J^?O] |  
{ >:K3y$]_  
nEndPos = nStartPos[i+1]; c1z5t]d   
} N1SRnJu<f  
nEndPos[nEndPos.length-1] = nFileLength; / )EB~|4']  
} v<-D>iJ  
} |UBJu `%  
ROfmAc  
.Kv@p jOr  
//启动子线程 O}%=c\Pb  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; <Q8bn?Z  
for(int i=0;i<nStartPos.length;i++) _}\&;  
{ : Z.mM5  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), aRV!0?fS  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), |g9^]bT  
nStartPos,nEndPos,i); ]:f1r8<3p  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); .3Ap+V8?  
fileSplitterFetch.start(); kBT cN D|  
} j9qN!.~mM  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), b/G0EcRw+  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); s}A]lY  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ]~oM'?&!  
nEndPos = " + nFileLength); Rp|:$5&nE  
// fileSplitterFetch[nPos.length-1].start(); ?K]k(ZV_+Y  
fHgfI@{=j  
K;Xn!:) V:  
//等待子线程结束 dxd}:L~z  
//int count = 0; y3xP~]n  
//是否结束while循环 xq]&XlA:ug  
boolean breakWhile = false; Z BYmAD  
71 2i |  
O-|3k$'\z  
while(!bStop) ~q9RZ#g13J  
{ 4gZN~_AI<  
write_nPos(); DQRt\!  
Utility.sleep(500); ' ZB%McS  
breakWhile = true; f]hW>-B(q  
(Hs frc  
.!`j3W]  
for(int i=0;i<nStartPos.length;i++) ,rN7X<s54  
{ >s>5k O  
if(!fileSplitterFetch.bDownOver) d p?uq'  
{ ]f\rB8k|&  
breakWhile = false; o 1b#q/  
break; 8=e \^Q+  
} ?@XO*|xkSk  
} '.bMkty#  
if(breakWhile) F%Xq}LMd  
break; (O&b:D/Y  
;uJVY)7a  
\GkcK$Y  
//count++; 6D+9f{~r  
//if(count>4) t2E_y6  
// siteStop(); c]O4l2nCL  
} Rbl(oj#  
< /}[x2w?]  
.h6h&[TEU  
System.err.println("文件下载结束!"); %AJdtJ@0H  
} ) HmpVH  
catch(Exception e){e.printStackTrace ();} i7p3GBXh[  
} $;">/ "7m  
~p8!Kb6  
O 8fh'6  
//获得文件长度 |ST&,a$(  
public long getFileSize() =]"PSY7p  
{ abF_i#  
int nFileLength = -1; L2:C6Sc  
try{ %URyGS]*  
URL url = new URL(siteInfoBean.getSSiteURL()); <;Xj4 J  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); rUuM__;d  
httpConnection.setRequestProperty("User-Agent","NetFox"); )PwDP  
U@*z#T#"m  
d9^h YS{  
int responseCode=httpConnection.getResponseCode(); `Ffn:=Do  
if(responseCode>=400) \t(/I=E8/  
{ xE}q(.]  
processErrorCode(responseCode); rVO+ vhih  
return -2; //-2 represent access is error ClEtw   
} Io:xG6yG  
N@) D,~  
ei"FN3Rm  
String sHeader; 1b't"i M  
y<gmp  
4iw+3 Q|  
for(int i=1;;i++) +[>m`XTq  
{ 2qEy"DKu  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ());  mbd@4u  
//Utility.log(in.readLine()); 4u;W1=+Vn  
sHeader=httpConnection.getHeaderFieldKey(i); w ggl,+7  
if(sHeader!=null) 'Kq%t M26!  
{ &^Xm4r%u_  
if(sHeader.equals("Content-Length")) `fL$t0 "  
{ Ms$kL'/  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); sQ_{zOUPh  
break; zi5;>Iv0}  
} mO\6B7V!  
} Ltu;sw  
else -PX {W)Aw  
break; EBn7waBS  
} -yC},tK  
} _qGkTiP  
catch(IOException e){e.printStackTrace ();} .|rpj&>g  
catch(Exception e){e.printStackTrace ();} d6Z;\f7[  
;Z8K3p  
o|UZdGu  
Utility.log(nFileLength); Bkcs4 x  
8 /\rmf\  
3cs'Oz<w  
return nFileLength; *l5/q\D  
} rSa 3u*xB  
\ET7  
FkRrW^?5G  
//保存下载信息(文件指针位置) m7d? SU  
private void write_nPos() )Z]8SED  
{ ,H|V\\  
try{ ('>!dXA$  
output = new DataOutputStream(new FileOutputStream(tmpFile)); H*!E*_  
output.writeInt(nStartPos.length); BK-{z).)  
for(int i=0;i<nStartPos.length;i++) w 5,-+&;  
{ z S^:Ng5  
// output.writeLong(nPos); K)&AR*Tc  
output.writeLong(fileSplitterFetch.nStartPos); |{Oe&j3|  
output.writeLong(fileSplitterFetch.nEndPos); VkUMMq{  
} 6 s*#y [$  
output.close(); = i `o+H  
} oo /#]a  
catch(IOException e){e.printStackTrace ();} aiz_6@Qfz*  
catch(Exception e){e.printStackTrace ();} ;]'mx  
} }PoB`H'K5  
Xo'_|-N+  
0(64}T)  
//读取保存的下载信息(文件指针位置) .)Du ;  
private void read_nPos() &'i>5Y  
{ 6)Kg!.n%f  
try{ /9i2@#J}W1  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); }2G'3msx  
int nCount = input.readInt(); ?*Jv&f#  
nStartPos = new long[nCount]; &,bJ]J)8O  
nEndPos = new long[nCount]; !x&/M*nBE  
for(int i=0;i<nStartPos.length;i++) [X;yJ$  
{ cE[4CCpy  
nStartPos = input.readLong(); X62GEqff  
nEndPos = input.readLong(); g }5lGz4  
} T,5]EHea  
input.close(); N5o jXX!l%  
} 0<fN<iR`  
catch(IOException e){e.printStackTrace ();} meE&, {  
catch(Exception e){e.printStackTrace ();} 3!#d&  
} 6=iz@C7r  
f7\$rx  
YQ;?N66  
private void processErrorCode(int nErrorCode) wOn.m  
{ | tyVC=${  
System.err.println("Error Code : " + nErrorCode); )]?sCNb  
} :6%wVy5  
<Knl6$B  
PjDYdT[  
//停止文件下载 l(*`,-pv:  
public void siteStop() 6"z:s-V  
{ Q.@9"&)t  
bStop = true; YG$Y4h" @"  
for(int i=0;i<nStartPos.length;i++) jq%Qc9y  
fileSplitterFetch.splitterStop(); #T&''a  
0)+F}SyyD  
gm(`SC?a  
} 3+0 $=ef  
} R>yoMk/u  
//负责部分文件的抓取 E&/#Ov  
**FileSplitterFetch.java T5Yu+>3  
*/ KHI-m9(  
package NetFox; 4uwI=UUB  
DFcgUEq  
EH=[!iW;  
import java.io.*; ol [   
import java.net.*; H)ud?vB6  
MQ7N8@!t  
,eW K~ pa  
public class FileSplitterFetch extends Thread { JN,4#,  
^cn%]X#.  
Il`35~a  
String sURL; //File URL =# <!s!  
long nStartPos; //File Snippet Start Position JgEPzHgx  
long nEndPos; //File Snippet End Position ">@]{e*  
int nThreadID; //Thread's ID `O5w M\Z  
boolean bDownOver = false; //Downing is over [RoOc)u  
boolean bStop = false; //Stop identical VG_ PBG(  
FileAccessI fileAccessI = null; //File Access interface AAb3Jf`UW  
fp^{612O?  
&gR)Y3  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException eVGO6 2|!  
{ jb|al[p\  
this.sURL = sURL; EyO=M~nsS  
this.nStartPos = nStart; UP'~D]J  
this.nEndPos = nEnd; .nl!KzO6g  
nThreadID = id; [3"k :  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 xf% _HMKc  
} JZ3CCf  
zmB6Y t  
hSr2<?yk  
public void run() 8iA[w-Pv  
{ f#f<Ii  
while(nStartPos < nEndPos && !bStop) V"K-aO&  
{ mSdByT+dG  
D<U^FT  
?71?Vd  
try{ K2|2Ks_CS  
URL url = new URL(sURL); |Tv}leJF  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Xt} 4B#  
httpConnection.setRequestProperty("User-Agent","NetFox"); H{hd1  
String sProperty = "bytes="+nStartPos+"-"; $lVR6|n  
httpConnection.setRequestProperty("RANGE",sProperty); W T~UEK'  
Utility.log(sProperty); 79`OB##  
1 etl:gcEC  
+-2o b90_m  
InputStream input = httpConnection.getInputStream(); [J{\Ke0<e1  
//logResponseHead(httpConnection); S#Q0aG j  
71b0MHNkvv  
QiKci%=SX  
byte[] b = new byte[1024]; E mG':K(  
int nRead; F \0>/  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) R RRF/Z;))  
{ )SU\s+"M  
nStartPos += fileAccessI.write(b,0,nRead); fVJlA  
//if(nThreadID == 1) p+7G  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); G`D rY;  
} )+7|_7 !x  
R5Pk>-KF  
p>oC.[:4a  
Utility.log("Thread " + nThreadID + " is over!"); (;!92ct[?  
bDownOver = true; $;iMo/  
//nPos = fileAccessI.write (b,0,nRead); aC90IJ8^  
} =M6Ph%  
catch(Exception e){e.printStackTrace ();} *qa.hqas  
} |VX )S!  
} I|n? 32F  
f`<elWgc"  
pq"Z,9,F%  
//打印回应的头信息 yE&WGpT  
public void logResponseHead(HttpURLConnection con) YY zUg  
{ &L[i"1a  
for(int i=1;;i++) !MXn&&e1  
{ ej,)< *  
String header=con.getHeaderFieldKey(i); %?`O .W  
if(header!=null) &=^YN"=Z  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); %1oB!+tv  
Utility.log(header+" : "+con.getHeaderField(header)); LwlO)|E  
else I1 pnF61U  
break; S;0z%$y  
} `5Bv2 wlIV  
} WKAG)4  
;FGS(.mjlC  
))%f"=:wt  
public void splitterStop() 5jq @ nq6  
{ B[ .$<$}G  
bStop = true; wrQ0 2?  
} 1=Kt.tuf  
[g bFs-B2/  
EQWRfx?d  
} t`1M}}.  
h#p[6}D  
}a !ny  
/* 2qdc$I&$  
**FileAccess.java eQz.N<f"  
*//文件访问(定位,写) Ay7PU  
package NetFox; +Wl]1 c/  
import java.io.*; (mr*Thy`@  
@HzK)%@  
;Fo7 -kK  
public class FileAccessI implements Serializable{ IL`LI J:O  
1N_T/I8_F  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 2n+ud ?|l  
RandomAccessFile oSavedFile; 1M.#7;#B3  
long nPos; XuWX@cK  
]4ck)zlv   
kbL7Xjk  
public FileAccessI() throws IOException *LMzq9n3o  
{ .sc80i4  
this("",0); [,MaAB  
} T X iu/g(  
;GE6S{~-  
4X",:B}  
public FileAccessI(String sName,long nPos) throws IOException (t){o> l  
{ <)pPq+  
oSavedFile = new RandomAccessFile(sName,"rw"); y4! :l=E^  
this.nPos = nPos; E,F^!4 rJ$  
oSavedFile.seek(nPos); )3A+Ell`  
} aS[y\9(**  
^62z\Y  
]&;In,z  
public synchronized int write(byte[] b,int nStart,int nLen) giH#t< )W  
{ =E$bZe8  
int n = -1; [NJ2rQ/w7  
try{ TV0sxod6  
oSavedFile.write(b,nStart,nLen); mZXtHFMu  
n = nLen; FA>.1EI  
} k]C k%[d  
catch(IOException e) +=Q:g,kP  
{ $9j>oUG  
e.printStackTrace (); FaWDAL=Vhk  
} St(jrZb  
+)bn}L>R l  
PjX V.gz  
return n; j^;P=L0=  
} <7>1Z 82)  
/_HTW\7,  
T`pDjT  
} l.]wBH#RS  
]'?Ue7  
Z m%,L$F*L  
/* C-)d@LWI  
**SiteInfoBean.java /F9Dg<#a  
*/ Aqmw#X  
package NetFox; O9-`e  
aeI0;u  
\2=I//YF  
public class SiteInfoBean { m&b1H9ymd  
@%*2\8}C!  
!s^XWsb8  
private String sSiteURL; //Site's URL z. X hE \  
private String sFilePath; //Saved File's Path M9o/6  
private String sFileName; //Saved File's Name oK-d58 sM  
private int nSplitter; //Count of Splited Downloading File u{va2n/  
'K02T:\iZ  
yH]Q;X '  
public SiteInfoBean() ]" e'z  
{//nSplitter的缺省值为5 MRXw)NAw  
//default value of nSplitter is 5 F!g1.49""  
this("","","",5); 8m=R" %h  
} tFc<f7k  
gE$Uv*Gj  
$M4Z_zle)  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) [<{r~YFjWW  
{ 1fsNQ!vQP  
sSiteURL= sURL; tY]?2u%)  
sFilePath = sPath; &4KUXn[F  
sFileName = sName; -0 <vmU  
this.nSplitter = nSpiltter; j;b>~_ U%  
) 3"!Q+  
Al6%RFt  
} mjg@c|rTG  
9XtO#!+48  
(yi zM  
public String getSSiteURL() HfhI9f_x  
{ yA"?Hv\o;  
return sSiteURL; {DKZ ~  
} :L+ xEL  
1goRO  
OomC%9/=,  
public void setSSiteURL(String value) U ^GVz%\  
{ ,g}$u'A+d  
sSiteURL = value; j!!s>7IZ  
} mF~]P8  
,D*bLXWh  
[^ r8P:Ad  
public String getSFilePath() ps:`rVQ7  
{ 4v _Hh<%  
return sFilePath; cf$ hIB)Oi  
} r ~UDK]?V  
BF2U$-k4  
Ri`6X_xU  
public void setSFilePath(String value) !*~QB4\2b  
{ i.W*Go+  
sFilePath = value; W!\%v"  
} $ -<(geI  
#yR&|*@  
s+fxv(,"c  
public String getSFileName() LXxQI(RO  
{ _+aR| AEC  
return sFileName; /D;ugc*3  
} U7jDm>I  
k*6"!J%A  
ReM]I<WuY  
public void setSFileName(String value) {*hvzS{1d  
{ n!~ $Z/  
sFileName = value; 3b0|7@_E  
} fgj$ u  
Yl'8" \HF  
_6c/,a8;*J  
public int getNSplitter() *tRsm"}  
{ R\7r!38  
return nSplitter; V[*>}XQER  
} . 70=xH  
c u";rnj  
AhA&=l i;  
public void setNSplitter(int nCount) ~XWBLU<  
{ 4OJD_  
nSplitter = nCount; `^^t#sT   
} >jmHe^rH  
} iZ}c[hC'3`  
#T>?g5I  
oGI'a:iff  
/* acke q#  
**Utility.java :tnW ivrwR  
*/ (X\]!'A  
package NetFox; T _UJ?W  
_U4@W+lhX_  
)nj fqg  
public class Utility { OS<GAA0  
z3L=K9)  
}{@y]DcdM4  
public Utility() !Z\Gv1  
{ z>,tP  
_fY9u2Y  
ey9hrRMR  
} jwLZC  
9a]o?>`E  
//线程睡眠 z<fd!g+^  
public static void sleep(int nSecond) Rsq EAdZw[  
{ kjsj~jwvv  
try{ owA8hGF  
Thread.sleep(nSecond); C<9GdN  
} 3[_WTwX0  
catch(Exception e) PbS1`8|4  
{ *3={s"a.(  
e.printStackTrace (); v_U/0 0  
} &XI9%h9|  
} -^`s#0( y^  
,ZY\})`p  
//日志 45[,LJaMd  
public static void log(String sMsg) <Dgf'Gr J  
{ gq*W 0S  
System.err.println(sMsg); T@P~A)>yo  
} N Czabl  
@@\px66  
 HRbv%  
public static void log(int sMsg) <<gW`KF   
{ #Q["[}flVv  
System.err.println(sMsg); "O$WfpKX  
} OIw[sum2  
} bw/mF5AsW  
qHyOaK Md  
Z{l`X#':  
/* `# !>}/m  
**TestMethod.java q\jq9)  
*/ e2V;6N  
package NetFox; ft@#[Bkx  
Y?K?*`Pkc1  
.+?]"1>]  
public class TestMethod { '?.']U,: $  
5$> buYF  
S[y_Ew zq  
public TestMethod() 0<4'pO.6Hq  
{ ///xx/weblogic60b2_win.exe xfX|AC  
try{ T1Z*>(M  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5);  Glx{Zu=  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); daSx^/$R  
SiteFileFetch fileFetch = new SiteFileFetch(bean); u^]Gc p  
fileFetch.start(); u-jc8W`Zd  
} B+R|fQ  
catch(Exception e){e.printStackTrace ();} Z]2z*XD  
nB :iG  
{hf_Xro&  
} ^e_uprZWm  
QALr   
@J6r;4|&  
public static void main(String[] args) z.)*/HGJm  
{ @Q nKaZ8jW  
new TestMethod(); %1GKN|7  
} ~X<$ l+5  
} 7tJ#0to  
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