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http断点续传简单实现(java)

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/* H].|K/-p  
**SiteFileFetch.java x="Wqcnj{  
*/ g}NO$?ndg  
package NetFox; -B;#pTG  
import java.io.*; SLKpl LO  
import java.net.*; Wd:pqhLh  
j{%;n40$  
%rylmioW>  
public class SiteFileFetch extends Thread { ]xQv\u  
dymq Z<  
.\ ;'>qy  
SiteInfoBean siteInfoBean = null; //文件信息Bean v>_@D@pr  
long[] nStartPos; //开始位置 ;=y"Z^  
long[] nEndPos; //结束位置 &eHRn_st5b  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 H)Btm  
long nFileLength; //文件长度 M76p=*  
boolean bFirst = true; //是否第一次取文件 5EFt0?G   
boolean bStop = false; //停止标志 inWLIXC,  
File tmpFile; //文件下载的临时信息 ,X.[37  
DataOutputStream output; //输出到文件的输出流 /K#k_k  
I8Aq8XBw  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) m\56BP-AM  
public SiteFileFetch(SiteInfoBean bean) throws IOException 5dePpFD5  
{ xU.1GI%UPu  
siteInfoBean = bean; fzIs^(:fl  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); }|.<EkA  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); |-Uh3WUE6  
if(tmpFile.exists ()) J#I RbO)  
{ B&]`OO>O  
bFirst = false; M7TLQqaF  
read_nPos(); `,qft[1  
} qYC&0`:H  
else \baY+,Dr+  
{ vqSpF6F q  
nStartPos = new long[bean.getNSplitter()]; F\ B/q  
nEndPos = new long[bean.getNSplitter()]; z&6_}{2,]  
} 8zp?WUb  
$*ff]>#  
DZSS  
V4[-:k  
} !Y ,7%  
x4WCAqi/2  
z`zz8hK.  
public void run() geme_  
{ eFG/!b<17  
//获得文件长度 n9B5D:.G  
//分割文件 fpR|+`k  
//实例FileSplitterFetch #*o0n>O  
//启动FileSplitterFetch线程 QTy=VLk43  
//等待子线程返回 }bb,Iib  
try{ gXxi; g  
if(bFirst) <Ht"t]u*Bn  
{ 24 [KGp  
nFileLength = getFileSize(); YO$Ig:a#  
if(nFileLength == -1) 8!E.3'jb  
{ IRN,=  
System.err.println("File Length is not known!"); 'Aq^z%|  
} P([!psgu  
else if(nFileLength == -2) ], lLD UZ\  
{ C%z)D1-  
System.err.println("File is not access!"); #`VAw ) eV  
} ;z'&$#pA  
else Sq5,}oT_{j  
{ \Y4(+t=4  
for(int i=0;i<nStartPos.length;i++) h.edb6  
{ TTXF r  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); $ VT)  
} .C'\U[A{  
for(int i=0;i<nEndPos.length-1;i++) L/i'6(="  
{ z@,pT"rb  
nEndPos = nStartPos[i+1]; 1SExl U  
} 7kLu rv  
nEndPos[nEndPos.length-1] = nFileLength; #_DpiiS,.Q  
} Nx 42k|8  
} U#z"t&o=L  
0t7N yKU  
p*Z<DEh#  
//启动子线程 =-r"@2HBq  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; if*V-$[I  
for(int i=0;i<nStartPos.length;i++) I~&*^q6 |  
{ 2P"643tz  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), LKM018H>  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), JWNN5#=fQ  
nStartPos,nEndPos,i); W Z'<iI  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); >V"{]v  
fileSplitterFetch.start(); E=I'$*C \D  
} ]3 "0#Y  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), &W\e 5X<A  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); xrf|c  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", [U&k"s?  
nEndPos = " + nFileLength); rS [4Pey  
// fileSplitterFetch[nPos.length-1].start(); *j3 U+HV  
'gY?=,dF>  
SY,ns*>1F  
//等待子线程结束 RdX+:!lD  
//int count = 0; tK3$,9+  
//是否结束while循环 MSCH6R"5  
boolean breakWhile = false; \l/(L5gY  
jwI2T$  
Q`k;E}x_-  
while(!bStop) JN8Rh  
{ aT,WXW*  
write_nPos(); y4kn2Mw;  
Utility.sleep(500); 7J);{ &x9h  
breakWhile = true; Oe Q[-e  
-HF?1c  
A|"T8KSMB  
for(int i=0;i<nStartPos.length;i++) v?He]e'  
{ -5*OSA:8x  
if(!fileSplitterFetch.bDownOver) _ s 3aaOL  
{ lV'?X%  
breakWhile = false; 1K/HVj+'.  
break; -C2!`/U  
} #w;"s*  
} :Racu;xf  
if(breakWhile) |>ztx}\  
break; )<QX2~m<  
)7.)fY$  
ew\:&"@2]w  
//count++; ;` L%^WZ;-  
//if(count>4) e#oK% {A  
// siteStop(); hJSvx  
} .i;.5)shsu  
LH54J;7 Y  
3HyOQD"{  
System.err.println("文件下载结束!"); QvbH " 7  
} "}X+vd``  
catch(Exception e){e.printStackTrace ();} /4+L2O[  
} "nz\YQdg  
r5gqRh}+  
'-"[>`[q  
//获得文件长度 Z` kVyuQ  
public long getFileSize() 2sGKn a  
{ NnAIL;WS  
int nFileLength = -1; E:qh}wY  
try{ kI"9T`owR  
URL url = new URL(siteInfoBean.getSSiteURL()); qlM<X?  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); P].Eb7I  
httpConnection.setRequestProperty("User-Agent","NetFox"); {`):X_$T  
yV`Tw"p  
u.A}&'H  
int responseCode=httpConnection.getResponseCode(); jTS8 qu  
if(responseCode>=400) k;cIEEdZD  
{ |dxWO  
processErrorCode(responseCode); k9eyl)  
return -2; //-2 represent access is error ?$`kT..j,u  
} \dQc!)&C9  
Yz;7g8HI  
3D6&0xTq  
String sHeader; 53hX%{3  
&B5&:ib1D  
`a52{Wa  
for(int i=1;;i++) R?1Z[N  
{ o~'p&f  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ^Zvb3RJg  
//Utility.log(in.readLine()); a=W%x{  
sHeader=httpConnection.getHeaderFieldKey(i); '`;=d<'  
if(sHeader!=null) Z'A 3\f   
{ qMEd R;o  
if(sHeader.equals("Content-Length")) 0to`=;JI  
{ u"zR_CzYc  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); %KVmpWku  
break; ]-t>F  
} b~UWFX#U  
} kB?/_a`]  
else vw>(JCR  
break; ktPM66`b  
} z4 =OR@ h  
} sf$hsPC^  
catch(IOException e){e.printStackTrace ();} Y;R,ph.a  
catch(Exception e){e.printStackTrace ();} g}R#0gkdk}  
E-^(VZ_Xj  
rV\G/)xL  
Utility.log(nFileLength); UB+~K/  
/*;a6S8q  
'__>M>[  
return nFileLength; 4IW fp&Q!  
} --diG$x.  
>!qtue7B  
k>i`G5Dh  
//保存下载信息(文件指针位置) )^8[({r~  
private void write_nPos() R<f F ^^  
{ p8XvfM  
try{ 4RctYMz  
output = new DataOutputStream(new FileOutputStream(tmpFile)); -uN{28;@  
output.writeInt(nStartPos.length); 6|lsG6uf  
for(int i=0;i<nStartPos.length;i++) v5@4 |u3ds  
{ 0Sk~m4fj(  
// output.writeLong(nPos); w;Azxcw  
output.writeLong(fileSplitterFetch.nStartPos); %AJ9fs4/  
output.writeLong(fileSplitterFetch.nEndPos); V5-!w0{  
} %h(%M'm?  
output.close(); kI a16m  
} 9:g A0Z  
catch(IOException e){e.printStackTrace ();} _1RvK? ;.{  
catch(Exception e){e.printStackTrace ();} E5A"sB   
} fn/?I \  
s#<fj#S  
t{B@k[|  
//读取保存的下载信息(文件指针位置) Z^Um\f   
private void read_nPos() Z796;qk  
{ u[KxI9Q  
try{ >VZxDJ$R  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); G0m$bi=z  
int nCount = input.readInt(); 4S*ifl  
nStartPos = new long[nCount]; <B T18u\  
nEndPos = new long[nCount]; Kn3Xn`P?  
for(int i=0;i<nStartPos.length;i++) R`$Y]@i&B  
{ 74N_>1!j  
nStartPos = input.readLong(); $aEv*{$y  
nEndPos = input.readLong(); I*j~5fsS'  
} _QHk&-Lp  
input.close(); T}z? i  
} x]`F#5j  
catch(IOException e){e.printStackTrace ();} >&fD:y'&  
catch(Exception e){e.printStackTrace ();} Kg~D~ +j  
} e}-fGtFx  
66-\}8f8a  
y$nI?:d  
private void processErrorCode(int nErrorCode) O13]H"O_  
{ `%~}p7Zu  
System.err.println("Error Code : " + nErrorCode);  z9&j  
} Ax\d{0/oL2  
_\yR/W~  
]%-U~avph  
//停止文件下载 Uc_ }="  
public void siteStop() g$2#TWW5  
{ [;aM8N  
bStop = true; /2d>nj  
for(int i=0;i<nStartPos.length;i++) $bp$[fX(e  
fileSplitterFetch.splitterStop(); sqpo5~  
WI| -pzg  
F0&ubspt\  
} WJ-.?   
} AvZ5?rN$  
//负责部分文件的抓取 j;48Yya'  
**FileSplitterFetch.java &?Erkc~#  
*/ UW}@oP$r  
package NetFox; 7xB]Z;:  
>Vx_Xv`Jwb  
byE0Z vDM  
import java.io.*; LH}9&FfjU  
import java.net.*; VJw7defc  
&n8Ja@Y]  
I)#8}[vK  
public class FileSplitterFetch extends Thread { rSt5 @f?  
'hWA&Xx +  
` ;mQ"lO  
String sURL; //File URL ceJ#>Rj  
long nStartPos; //File Snippet Start Position "9^b1UH<  
long nEndPos; //File Snippet End Position \tvL<U"'  
int nThreadID; //Thread's ID bh5P98s  
boolean bDownOver = false; //Downing is over W tw,YFT  
boolean bStop = false; //Stop identical 6wu`;>  
FileAccessI fileAccessI = null; //File Access interface >`&2]Wc)  
)N~ p4kp  
r?Mf3U^G  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException PfU\.[l$  
{ #>KiX84  
this.sURL = sURL; NwOV2E6@OW  
this.nStartPos = nStart; 6q'Q ?Uw^  
this.nEndPos = nEnd; ,6MJW#~]  
nThreadID = id; Hmm0H6&u  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 'MX|=K!C  
} 0+qC_ISns  
o:cTc:l)  
@,= pG  
public void run() ,J+L_S+B~  
{ 9XQE5^  
while(nStartPos < nEndPos && !bStop) bJ 6ivz  
{ 6&'kN 2  
wXp:XZ:]T  
QsxvA;7%  
try{ wmVb0~[  
URL url = new URL(sURL); 2V% z=  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); T#!% Uzz  
httpConnection.setRequestProperty("User-Agent","NetFox"); U5-8It2OR  
String sProperty = "bytes="+nStartPos+"-"; .]KC*2  
httpConnection.setRequestProperty("RANGE",sProperty); aY,Bt  
Utility.log(sProperty); jyF*JQjK4  
B_[I/ ?  
$ S3b<]B  
InputStream input = httpConnection.getInputStream(); A p?,y?  
//logResponseHead(httpConnection); JAjiG^]  
?kZ-,@h:  
3mYW]  
byte[] b = new byte[1024]; `Rq|*:LV  
int nRead; "XV@O jr E  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Q_fgpjEh/t  
{ M0C)SU5"  
nStartPos += fileAccessI.write(b,0,nRead); _2`b$/)-  
//if(nThreadID == 1) -Wmb M]Z  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); a%HNz_ro  
} *szs"mQ/  
4P)#\$d:  
|6?s?tC"u  
Utility.log("Thread " + nThreadID + " is over!"); xc @$z* w  
bDownOver = true; d>I)_05t  
//nPos = fileAccessI.write (b,0,nRead); NTZ3Np`  
} w+j\Py_G"  
catch(Exception e){e.printStackTrace ();} 2.Ww(`swL  
} <G<5)$ S  
} E <j=5|0t  
6J JA"] `  
S}h d,"I  
//打印回应的头信息 3  ;F  
public void logResponseHead(HttpURLConnection con) 2uT6M%OC  
{ ,)d`_AD+5  
for(int i=1;;i++) ,KM%/;1Dm  
{ ` W );+s  
String header=con.getHeaderFieldKey(i); OMmfTlM%  
if(header!=null) ; \co{_&D  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ?-Of\fNu  
Utility.log(header+" : "+con.getHeaderField(header)); =,ax"C?pR  
else ,vvfk=-  
break; $ e L-fg  
} \VIY[6sn\M  
} >{~xO 6H  
WdS1v%  
lU=VCuW!  
public void splitterStop() l}-k>fug  
{ ziO(`"v  
bStop = true; fX,O9d$  
} WW3Jxd  
A_ &IK;-go  
%YF /=l  
} {_.(,Z{  
mMZrBz7r  
X#0yOSR  
/* 5M'cOJ  
**FileAccess.java 9cN@y<_I  
*//文件访问(定位,写) $4ZV(j]  
package NetFox; By!u*vSev  
import java.io.*; FVP,$  
+&f_k@+  
 Br s}  
public class FileAccessI implements Serializable{ *wmkcifF;  
nIBeZof  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 qA!4\v={  
RandomAccessFile oSavedFile; {df;R|8 l  
long nPos; ?Q=(?yR0]  
/{8Y,pZbu  
@##}zku  
public FileAccessI() throws IOException 4mp)v*z  
{ CpX[8>&osD  
this("",0); =&"pG` x  
} @%u}|iF|  
?uTuO  
ph(LsPT-  
public FileAccessI(String sName,long nPos) throws IOException q0>9T  
{ `l?MmIJ  
oSavedFile = new RandomAccessFile(sName,"rw"); e'G3\h}#  
this.nPos = nPos; I;_T_m4.q  
oSavedFile.seek(nPos); \j)c?1*$  
} $$4flfx  
BIx*(  
hV`?, ~K  
public synchronized int write(byte[] b,int nStart,int nLen) d@*dbECG  
{ s/~[/2[bnf  
int n = -1; ? B|i  
try{ im:[ViR {  
oSavedFile.write(b,nStart,nLen); 9%ct   
n = nLen; m^ar:mK@  
} Xu_1r8-|=b  
catch(IOException e) r:0RvWif  
{ Dvz 6 E  
e.printStackTrace (); VY~*QF~P  
} =|$U`~YB  
L&NpC&>wD  
qx >Z@o  
return n; ;{iTS sb  
} uW[AnQ1w  
Z9% u,Cb  
Pk5\v0vkg  
} >yVrIko  
^56D)A=  
3#udz C  
/* V5h_uGOD  
**SiteInfoBean.java e>!]_B1ad  
*/ 5gx;Bp^_  
package NetFox; *)\y52z  
5$Kv%U  
.|L9}<  
public class SiteInfoBean { 60>g{1]  
#vy[v22  
&2@Rc?!6_P  
private String sSiteURL; //Site's URL !m_y@~pV#u  
private String sFilePath; //Saved File's Path '5T:*Yh  
private String sFileName; //Saved File's Name 'X&"(M  
private int nSplitter; //Count of Splited Downloading File Avljrds+7  
5c%Fb :BW=  
h= YTgJ  
public SiteInfoBean() F)'_,.?0  
{//nSplitter的缺省值为5 Bgsi$2hI  
//default value of nSplitter is 5 !VG ]~lc  
this("","","",5); xQ?$H?5B<  
} qIzv|Nte  
eK3d_bF+  
7I(QTc)*  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) <Z]j89wzDZ  
{ ep48 r>  
sSiteURL= sURL; | z}VP-L  
sFilePath = sPath; .bh 7  
sFileName = sName; UY.o,I> s  
this.nSplitter = nSpiltter; |P9)*~\5  
@frV:%  
#f=41d%  
} Ix=(f0|  
yG#x*\9  
gK *=T  
public String getSSiteURL() 5X]f}6kT  
{ \)MzUOZn  
return sSiteURL; nM8'="$  
} %3HF_DNOY=  
$Zrc-tkV  
YO@~y *,  
public void setSSiteURL(String value) K"Irg.  
{ G-o6~"J\  
sSiteURL = value; G&6`?1k  
} /W}"/W9  
K7qR  
6k37RpgH  
public String getSFilePath() Y|-&=  
{ 8k Sb92  
return sFilePath; /(s N@kt  
} w);Bet  
v&66F`  
cSTL.QF  
public void setSFilePath(String value) Qq.Ja%Zq  
{ 5]3Mj*u\  
sFilePath = value; uD4W@*PYr  
} eM7 F8j  
>v/%R~BuX  
UD2 l!)rW  
public String getSFileName() _*t75e$-  
{ ZU 7u>  
return sFileName; g</Mk^CE  
} <@n3vO6  
`,c~M  
ub4(g~E  
public void setSFileName(String value) e:QH3|'y  
{ j2hp*C'^  
sFileName = value; gb^'u  
}  `7V'A  
^NxKA'oWQ  
fzjtaH?  
public int getNSplitter() 7zNfq.Ni~  
{ r8_MIGM'  
return nSplitter; l>7?B2^<E  
} P$/Y9o  
\&v)#w  
"t>H B6^  
public void setNSplitter(int nCount) +5Y;JL<%/  
{ ~^g*cA t}  
nSplitter = nCount; %W2 o`W$  
} S)^eHuXPI  
} jyRz53  
'z};tIOKJk  
O3p<7`K<4  
/* 8(-N;<Ef2  
**Utility.java H ;HFen|  
*/  zK:2.4  
package NetFox; 6ZC~q=my  
\%#luk@:  
Oh7wyQiV  
public class Utility { Gfle"_4m8  
!@)tkhP  
drB$q [Ak9  
public Utility() (%]M a  
{ ~ #P` 7G  
cMAY8$  
=A/$[POr  
} MnW"ksH  
;'4Kg@/  
//线程睡眠 }~ga86:n0  
public static void sleep(int nSecond) n=h!V$X   
{ ^QTkre  
try{ zgSv -h+f  
Thread.sleep(nSecond); `S]DHxS  
} B!1L W4^  
catch(Exception e) vPu {xy  
{ M9(Kxux#  
e.printStackTrace (); QLH6Nmk  
} MBFn s/  
} }Szs9-Wns  
tHH @[E+h  
//日志 t)l^$j !h@  
public static void log(String sMsg) chU,));F  
{ 3hR3)(+1  
System.err.println(sMsg); 04!akPP<  
} +tv"j;z  
SiT5QJe  
J~5+=V7OV  
public static void log(int sMsg) | +aD%'|  
{ r 4+%9)  
System.err.println(sMsg); JjBlje  
} =K6{AmG$  
} ,@@FAL  
%uy?@e  
fSm|anuKZe  
/* X0]5I0YP  
**TestMethod.java v ,)vW5jGI  
*/ vsbD>`I  
package NetFox; -+ Mh( 'K  
~"U^N:I"  
(=QiXX1r  
public class TestMethod { G -RE  
t",b.vki\z  
{pk&dB _Bu  
public TestMethod() 22v= A6 =  
{ ///xx/weblogic60b2_win.exe HVM(LHm=:  
try{ NYF 7Ep; _  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); .v#Tj|w^  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); E"t79dD  
SiteFileFetch fileFetch = new SiteFileFetch(bean); BGL-lJrG  
fileFetch.start(); \7tJ)[0aF  
} c8qwsp  
catch(Exception e){e.printStackTrace ();} M{`uI8vD  
#j6qq3OG  
_n!W4zwi  
} axiP~t2  
jsIT{a*]  
SHUn<+/e  
public static void main(String[] args) jRSY`MU}t+  
{ zFO#oW,D  
new TestMethod(); ]*yUb-xY  
} j{H,{x  
} [7=?I.\Cr7  
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