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http断点续传简单实现(java)

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/* ?lD)J?j  
**SiteFileFetch.java VrPsy) J68  
*/ [yN+(^ i  
package NetFox; ./XX  
import java.io.*; SZe55mK`  
import java.net.*; ;@qS#7SRB  
>Vt2@Ee  
rz_W]/G-P  
public class SiteFileFetch extends Thread { \7b, Mz!  
[k%hl`}  
3E;@.jD  
SiteInfoBean siteInfoBean = null; //文件信息Bean KHZ[drb6$  
long[] nStartPos; //开始位置 d]s^?=gM  
long[] nEndPos; //结束位置 ~) _Nh  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 K0( S%v|,}  
long nFileLength; //文件长度 oB5\^V$  
boolean bFirst = true; //是否第一次取文件 Ph""[0n%o  
boolean bStop = false; //停止标志 O>pX(DS L  
File tmpFile; //文件下载的临时信息 4@fv%LOQo  
DataOutputStream output; //输出到文件的输出流 .%n_{ab1  
 ,==_u  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) v}u]tl$,  
public SiteFileFetch(SiteInfoBean bean) throws IOException =>5Lp  
{ BM?!?  
siteInfoBean = bean; kE<CuO  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); <!RkkU& 6  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 34!.5^T  
if(tmpFile.exists ()) KX9IC 5pR  
{ 7mYcO3{5{  
bFirst = false; j H2)8~P  
read_nPos(); -(?/95 Y  
} @-[}pZ/  
else 9#U]?^DJ@  
{ F hUi{`  
nStartPos = new long[bean.getNSplitter()]; (K=0c 6M3=  
nEndPos = new long[bean.getNSplitter()]; %]I#]jR  
} &zy%_U2%  
AVD hgJv  
J' uaZI>'  
{Ia1H  
} <$-^^b(y  
hT-^1 :N  
_Sd^/jGpU  
public void run() ben-<3r  
{ |OCiq|#  
//获得文件长度 <e BmCrJ  
//分割文件 Rs"=o>Qu  
//实例FileSplitterFetch 6 agG*x  
//启动FileSplitterFetch线程 8a 8a:d  
//等待子线程返回 k@lJ8(i^qU  
try{ SeXgBbGAne  
if(bFirst) 9Zl4NV&B  
{ ;6PU  
nFileLength = getFileSize(); VI4mEq,V  
if(nFileLength == -1) 95#]6*#[4!  
{ u=InE|SH  
System.err.println("File Length is not known!"); ;&J>a8B$  
} >xo<i8<Miv  
else if(nFileLength == -2) =nCA=-Jv  
{ dj (&"P  
System.err.println("File is not access!"); -(TC'  
} ]*| hd/j  
else 9*I[q[>9  
{ =JE<oVP8  
for(int i=0;i<nStartPos.length;i++) wicsf<]  
{ #Q7:Mu+  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); L^t%p1R  
}  DlCN  
for(int i=0;i<nEndPos.length-1;i++) Wo&22,EB  
{ +I5\ `By=  
nEndPos = nStartPos[i+1]; X8Z) W?vu  
} QDYuJ&!h  
nEndPos[nEndPos.length-1] = nFileLength; C2rG3X^~Jm  
} S\N l|U[  
} " J9  
5fk A?Ecqq  
j7&#R+f  
//启动子线程 M**Sus87Q  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; gD)M7`4  
for(int i=0;i<nStartPos.length;i++) s3A(`heoq  
{ 9U<WR*H  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), S>x@9$( ym  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), "vybVWEE  
nStartPos,nEndPos,i); &M@ .d$<C  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); |GQq:MB;z  
fileSplitterFetch.start(); W gyRK2#!  
} `?=3[  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), A nl1+  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ]*a(^*}A%  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 0O'M^[=d.8  
nEndPos = " + nFileLength); #0r^<Yn  
// fileSplitterFetch[nPos.length-1].start(); {'zS8  
 )XonFI  
r&R~a9+)  
//等待子线程结束 )R `d x  
//int count = 0; UUWRC1EtI  
//是否结束while循环 >b\|%=(x!*  
boolean breakWhile = false; v0) %S  
E!}'cxb^  
g0biw?  
while(!bStop) fsOlg9  
{ PtuRXx  
write_nPos(); BDfMFH[1  
Utility.sleep(500); 90+Vw`Gz=  
breakWhile = true; /'{vDxZf R  
<fBJ@>  
tBzE(vW  
for(int i=0;i<nStartPos.length;i++) [K #$W  
{ XO?WxL9k]  
if(!fileSplitterFetch.bDownOver) +?6]Vu&|f  
{ SPb`Q"  
breakWhile = false; g~21|Sa$[  
break; /xgC`]-  
} y'>9' /&  
} OcF_x/#  
if(breakWhile) bl!pKOY  
break; l5^Q  
Yl au  
W<&/5s  
//count++; 5KB Z-,  
//if(count>4) nWCJY:q;5  
// siteStop(); n+=7u[AZi  
} ).,twf58  
<k1muSe  
Yqh-U%"'  
System.err.println("文件下载结束!"); ES,JdImZ|  
} k"[AV2UW1  
catch(Exception e){e.printStackTrace ();} *fi`DiO  
} ,.{M1D6'R`  
W="pu5q$5  
rJf{YUZe  
//获得文件长度 BPW.&2?<  
public long getFileSize() @)Vb?|3  
{ nO6UlY  
int nFileLength = -1; 2va[= >_  
try{ p?Ux1S  
URL url = new URL(siteInfoBean.getSSiteURL()); ]{i0?c  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); =zAFsRoD_B  
httpConnection.setRequestProperty("User-Agent","NetFox"); ?8grK  
=\ 8 x  
)$Ib6tYY  
int responseCode=httpConnection.getResponseCode(); ]Y$Wv9 S6  
if(responseCode>=400) nO`[C=|  
{ ^WWr8-  
processErrorCode(responseCode); s +S6'g--  
return -2; //-2 represent access is error W)Y-^i5  
} #('R`~  
8yI4=P"F,  
^K[xVB(&  
String sHeader; ]Y?ZUSCJ  
-|#/KKF  
JK{2 hr_a  
for(int i=1;;i++) y<IHZq`C3  
{ L6qK3xa}  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); L1lDDS#  
//Utility.log(in.readLine()); E}w5.1  
sHeader=httpConnection.getHeaderFieldKey(i); ;gHcDnH)  
if(sHeader!=null) e"EGqn&!  
{ Qj /H$  
if(sHeader.equals("Content-Length")) JUGq\b&m  
{ 0"@J*e#  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); QN#Lbsd  
break; ?zsRs?rc0  
} 3:sc%IDP  
} 1A;,"8kBd  
else A Ef@o+A  
break; ]_s;olKNI  
} HIj:?y  
} o|84yT!~  
catch(IOException e){e.printStackTrace ();} A0.xPru1p  
catch(Exception e){e.printStackTrace ();} ={h^X0<s9  
CO ZfR~}  
JeVbFZ8  
Utility.log(nFileLength); wuCZz{c7  
PCDvEbpG  
'q/C: Yo  
return nFileLength; w5-^Py  
} ~ c~j  
P-^-~/>n  
Lo[;{A$u  
//保存下载信息(文件指针位置) ='Oxy  
private void write_nPos() .d#Hh&jj  
{ 92,@tNQQ}  
try{ (ux9"r^g;x  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ga1b%5]v.  
output.writeInt(nStartPos.length); ZS3T1 <z  
for(int i=0;i<nStartPos.length;i++) o+^e+ptc  
{ +N~{6*@uz,  
// output.writeLong(nPos);  ^LSD_R^N  
output.writeLong(fileSplitterFetch.nStartPos); \ X6y".|-  
output.writeLong(fileSplitterFetch.nEndPos); zuJ` 704  
} GXv2B%i8  
output.close(); [m x}n+~  
} - 3<&sTR  
catch(IOException e){e.printStackTrace ();} /'v!{m  
catch(Exception e){e.printStackTrace ();} `x L@%  
} yYaYuf  
)zP"Uuu  
Z>NA 9:  
//读取保存的下载信息(文件指针位置) F')E)tV  
private void read_nPos() \"yR[.Q?   
{ T sJ71  
try{ /3"S_KE1@+  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); &7,/^ >">  
int nCount = input.readInt(); M-!#-l  
nStartPos = new long[nCount]; Z +<Y.*6  
nEndPos = new long[nCount]; :w4H$+j  
for(int i=0;i<nStartPos.length;i++) ,:81DA  
{ $Ixd;`l*  
nStartPos = input.readLong(); da8 R.1o  
nEndPos = input.readLong(); ~Ty6]A  
} 4g.S!-H@R  
input.close(); S[rfcL"  
} A}"uEk(R  
catch(IOException e){e.printStackTrace ();} oY@]&A^ah  
catch(Exception e){e.printStackTrace ();} m1p% ,  
} hB:+_[=Kj.  
K^I$05idi  
)gR3S%Ju  
private void processErrorCode(int nErrorCode) dt>!=<|k  
{ Z%-uyT@a  
System.err.println("Error Code : " + nErrorCode); 6|Rj YX  
} brn>FFAwO  
@:9mTP7  
gr>FLf   
//停止文件下载 R,zp&L  
public void siteStop() 4 >D5t)254  
{ fG7-0 7  
bStop = true; PO2]x:  
for(int i=0;i<nStartPos.length;i++) r7)iNTQ1  
fileSplitterFetch.splitterStop(); E?m W4?  
.e:+Ek+  
NXE1v~9V  
} "yXqf%CGE  
} Y}x_ud,  
//负责部分文件的抓取 zWdz9;=_  
**FileSplitterFetch.java m]\d9%-AT&  
*/ OL&VisJ{75  
package NetFox; NL ceBok  
0g@*N4  
RQn3y-N]  
import java.io.*; 7nPm{=B G  
import java.net.*; wi:d!,P`e  
wK%x|%R[  
tkix@Q!;\  
public class FileSplitterFetch extends Thread { 9+>%U~U<  
KEr?&e  
k .F(*kh  
String sURL; //File URL IZ_ B $mo  
long nStartPos; //File Snippet Start Position 9l7 youZ]  
long nEndPos; //File Snippet End Position Q[Tbdc%1EG  
int nThreadID; //Thread's ID Nk>6:Ho{G  
boolean bDownOver = false; //Downing is over ZOzyf/?.  
boolean bStop = false; //Stop identical w?c~be$  
FileAccessI fileAccessI = null; //File Access interface 4_Rv}Y d  
&-Z#+>=H(  
:Z5kiEwYM  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException >LB x\/  
{ h6Hop mWVx  
this.sURL = sURL; odq3@ ziO  
this.nStartPos = nStart; l_=kW!l  
this.nEndPos = nEnd; <gr2k8m6$  
nThreadID = id; m9m~2   
fileAccessI = new FileAccessI(sName,nStartPos);//定位 z;i4F.p  
} x\(yjNZH  
TGPHjSZ1  
7o M]qLF  
public void run() q/YO5>s15  
{ =0mGfT c  
while(nStartPos < nEndPos && !bStop) o Bp.|8-  
{ 5s2/YG=  
>5]w\^QN9_  
!]WC~#|{B  
try{ 4> [tjz.?k  
URL url = new URL(sURL); B.[5N;c  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ["?WVXCF8|  
httpConnection.setRequestProperty("User-Agent","NetFox"); < 'qtqUL\  
String sProperty = "bytes="+nStartPos+"-"; kI$p~  
httpConnection.setRequestProperty("RANGE",sProperty); M7IQJFra  
Utility.log(sProperty); DWJkN4}o  
qT_E=)1  
2$QuR~  
InputStream input = httpConnection.getInputStream(); t!vlZNc  
//logResponseHead(httpConnection); x1*@PiO,.  
Z{.L_ ]$ I  
D61e  
byte[] b = new byte[1024]; ,}42]%$ G  
int nRead; 9]/j u  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) W.U|mNJ$  
{ \~q cYp  
nStartPos += fileAccessI.write(b,0,nRead); o!t1EPJE*  
//if(nThreadID == 1) -wV0Nv(V8  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 38q0iAH  
} 3H47 vm(`  
[ w1"  
\ 8X8N CM  
Utility.log("Thread " + nThreadID + " is over!"); h!>NS ?X7  
bDownOver = true; \\~4$Ai[  
//nPos = fileAccessI.write (b,0,nRead); t]%! vXo  
} kOuQR$9s  
catch(Exception e){e.printStackTrace ();} ^l/$ 13=  
} } u7&SU  
} q&wXs/$a  
\it<]BN  
,o j\=2  
//打印回应的头信息 u~d&<_Z  
public void logResponseHead(HttpURLConnection con) DK;/eZe  
{ OECXNx  
for(int i=1;;i++) X{riI^(  
{ <ByDT$E_  
String header=con.getHeaderFieldKey(i); IN9o$CZ:  
if(header!=null) MRHkQE+K@8  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); P1l@K2r  
Utility.log(header+" : "+con.getHeaderField(header)); #[#dc]D  
else KBFAV&  
break; DWH)<\?  
} S\UM0G}v  
} k||DcwO  
I2=Kq{  
RsDI7v  
public void splitterStop() #8d$%F))  
{ &^YY>]1Py  
bStop = true; ,/>~J]:\;  
} b511qc"i>M  
57b;{kl  
VI`x fmVOQ  
} way-Q7  
X_eV<]zA+  
|"Oazll  
/* MPd#C*c  
**FileAccess.java /_554q  
*//文件访问(定位,写) Lsozl<@  
package NetFox; %rRpUrnm  
import java.io.*; 5+O#5" v_  
4[&6yHJ^  
6l$o^R^D  
public class FileAccessI implements Serializable{ '17u Wq  
rbP3&L  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 yx}Z:t  
RandomAccessFile oSavedFile; .ODtduURe  
long nPos; =;$&:Zjy/%  
kB]|4CG{  
n%<.,(.(S  
public FileAccessI() throws IOException zj;y`ENj  
{ F<w/@ .&m  
this("",0); &,&oTd.  
} vP'R7r2Yx  
3-8Vw$u  
{UYqRfgbZ  
public FileAccessI(String sName,long nPos) throws IOException uyG4zV\h*  
{ $P@P}%2  
oSavedFile = new RandomAccessFile(sName,"rw"); t5N4d  
this.nPos = nPos; |R*fw(=W  
oSavedFile.seek(nPos); _H8)O2mJ  
} +o/;bm*U<K  
O'-lBf+<  
1|cmmUM-'v  
public synchronized int write(byte[] b,int nStart,int nLen) u-k?ef  
{ {+t'XkA  
int n = -1; ~ab"q %  
try{ *qBMt[a  
oSavedFile.write(b,nStart,nLen); Qzh:*O  
n = nLen; R/O_*XY  
} 1ck2Gxn  
catch(IOException e) W^+b gg<.  
{ =8dCk\/  
e.printStackTrace (); R4JO)<'K&  
} l>&)_:\  
a4: PufS  
e:V,>RbC0s  
return n; ]@?3,N  
} tXK hkt`  
y9)l,@D  
Qw5M\   
} C.(ZXU7  
`?6m0|\@  
L6A6|+H%E  
/* y~S[0]y>  
**SiteInfoBean.java <qRw! 'S^  
*/ `g :<$3}  
package NetFox; u%[*;@;9+  
jv|IV  
kx UGd)S  
public class SiteInfoBean { LbYI{|_Js  
>LU*F|F]B  
[bOy, ^@4  
private String sSiteURL; //Site's URL >PGm}s_  
private String sFilePath; //Saved File's Path |_=jXf\TL  
private String sFileName; //Saved File's Name zPkg3H  
private int nSplitter; //Count of Splited Downloading File 0`ib_&yI  
X}usyO'pW  
7_Q86o  
public SiteInfoBean() xZhD6'Zzz  
{//nSplitter的缺省值为5 5^d%+*l;q  
//default value of nSplitter is 5 s_*eX N  
this("","","",5); &gEu%s^wR  
} Vd1K{rH#  
y?unI~4tC  
7T2W% JT-,  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) "+ Qh,fTt  
{ #/jHnRrQ   
sSiteURL= sURL; q2<J`G(tZ  
sFilePath = sPath; 7R2)Klt  
sFileName = sName; 9vj:=,TNu  
this.nSplitter = nSpiltter; R&alq  
4*9Dh  
F#<P FT4i  
} .$OInh  
1)PR]s:-m@  
ntkinbbD  
public String getSSiteURL() bA^a@ lv a  
{ z vYDE]  
return sSiteURL; n `Xz<Q!  
} 2E1TJ.[BS  
=91'.c<  
vaxg^n|v9  
public void setSSiteURL(String value) G[^G~U\+!  
{ V[bc-m  
sSiteURL = value; \S@A /t6pa  
} N7jRdT2k%  
x> q3w# B  
`k\1vum  
public String getSFilePath() mcXakWmi  
{ q7PRJX  
return sFilePath; Z{CL!  
} jI V? p  
/&|pXBY$;  
Yptsq@s  
public void setSFilePath(String value) LK%B6-;~-  
{ =Ffq =<  
sFilePath = value; X}=f{/\S  
} xXYens}  
B*AMo5  
w:LCm `d  
public String getSFileName() 4>Y\2O?**  
{ &B85;  
return sFileName; ,6bMf z  
} JS:lysu  
D7(t6C=FP  
xq)/QR  
public void setSFileName(String value) Zll^tF#  
{ zn x_p /V  
sFileName = value; 0X-2).n u  
} \O?B9_  
stG&(M  
&sgwY  
public int getNSplitter() *u>\&`h=  
{ 3.H-G~  
return nSplitter; ;E"mB4/)  
} 8JrGZ8Q4RM  
!491 \W0ZH  
W9Lg}[>:)  
public void setNSplitter(int nCount) V<pqc&f .  
{ -Mvw'#(0  
nSplitter = nCount; vWovR`  
} htRZ}e  
} Pb;`'<*U  
F)5Aq H/p  
79x9<,a)  
/* 7x]nY.\  
**Utility.java {4 d$]o0V  
*/ 4<K`yU]"  
package NetFox; "poTM[]tZ7  
=4 H K  
bx^EaXj(r  
public class Utility { fYjsSUnf  
]."c4S_)|  
W>bW1h  
public Utility() kw~H%-,]  
{ $Ig,cTR.b  
S: uEK  
SkA'+(  
} XXcf!~uO  
EXcjF  
//线程睡眠 xi\RUAW  
public static void sleep(int nSecond) wIj2 IAD  
{ E <SE Fn  
try{ G0> Wk#or  
Thread.sleep(nSecond); I yN9 +  
} Y]K]]Ehp  
catch(Exception e) CEq]B:[IC  
{ Kc\'s65.]  
e.printStackTrace (); {:X];A$  
} ,O)\,tg  
} TkoXzG8yE<  
3/=QZ8HA&-  
//日志 jFT V\|C  
public static void log(String sMsg) 26VdRy{[  
{ 2H+DT-hK  
System.err.println(sMsg); :t S"sM  
} WG luY>C;  
ee^_Dh4  
:*'?Ac ?  
public static void log(int sMsg) :+Ax3  
{ _5w?v~65  
System.err.println(sMsg); N:[;E3?O  
} 5)5bt q)[  
} M9g\/]Io;  
PjW+V`  
c\{}FGC  
/* C'2 =0oou  
**TestMethod.java Pq>[q?>?  
*/ I 47GQho  
package NetFox; HHTsHb{7  
U hhmG+  
XWQ0V  
public class TestMethod { >#U <#  
i!oj&&  
dKQV4dc>  
public TestMethod() DjzBG*f/  
{ ///xx/weblogic60b2_win.exe o[[r_v_d  
try{ r{R7"  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); "HfU,$[  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); L{A-0Ffh  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ]</4#?_  
fileFetch.start(); +()t8,S,  
} ^MHn2Cv/~  
catch(Exception e){e.printStackTrace ();} *Yu\YjLPG  
-yQ\3wli`  
^r_lj$:+$  
} LA`V qJ  
[ky6E*dV`  
![]I%'s  
public static void main(String[] args) )c >B23D  
{ <ii1nz  
new TestMethod(); E5BgQ5'  
} 'b?.\Bm;  
} |z]2KjF&w-  
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