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http断点续传简单实现(java)

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/* `?JrC3  
**SiteFileFetch.java rvE!Q=y~  
*/ qC\$>QU}  
package NetFox; <Mc:Cg8>  
import java.io.*; M`?/QU~  
import java.net.*; LR)is  
\yG_wZs  
f`Wfw3  
public class SiteFileFetch extends Thread { /HzhgMV3  
nBiSc*  
0^(.(:  
SiteInfoBean siteInfoBean = null; //文件信息Bean U}A+jJ  
long[] nStartPos; //开始位置 r~s03g0  
long[] nEndPos; //结束位置 l"*>>/U k  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 He!0&B\7h  
long nFileLength; //文件长度 _ux 6SIyp`  
boolean bFirst = true; //是否第一次取文件  j Mp{  
boolean bStop = false; //停止标志 b!.# `.  
File tmpFile; //文件下载的临时信息 G|O"Kv6  
DataOutputStream output; //输出到文件的输出流 W>@%d`>o5  
L0&!Qct  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) V$v;lvt^Uq  
public SiteFileFetch(SiteInfoBean bean) throws IOException M2xUs  
{ xBw"RCBz^  
siteInfoBean = bean; :&:>sd(QD  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); RmNF]"3%  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); !m(6/*PAl  
if(tmpFile.exists ()) uk'<9g^  
{ .`h+fqa  
bFirst = false; #&8 Opo(  
read_nPos(); i'5bPW  
} wUV%NZB  
else &0C!P=-p  
{ 6nq.~f2`  
nStartPos = new long[bean.getNSplitter()]; {W4t]Ff  
nEndPos = new long[bean.getNSplitter()]; 9Akwr}  
} cEQa 6  
x4( fW\  
:<(<tz7dj  
cXCczqabv  
} -"nYCF  
,pG63&?j  
h n ]6he  
public void run() y(z U:.  
{ QA9vH'  
//获得文件长度 iLI]aZ   
//分割文件  nm~  
//实例FileSplitterFetch J~Ph)|AiS  
//启动FileSplitterFetch线程 >WEg8'#O  
//等待子线程返回 nagto^5X  
try{ vVf!XZF  
if(bFirst) )/pPY  
{ 5(|ud)v  
nFileLength = getFileSize(); HWU{521  
if(nFileLength == -1) ZT8j9zs  
{ mT9\%5d3  
System.err.println("File Length is not known!"); 68>zO %  
} ?d0Dfqh_  
else if(nFileLength == -2) :)yM9^<D  
{ ^KF'/9S  
System.err.println("File is not access!"); S\rfR N  
} ;lEiOF+d  
else +=8Po'E^!d  
{ x}[` -  
for(int i=0;i<nStartPos.length;i++) 6qDD_:F  
{ NNdS:(  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); #e=^-yE  
} Yt'o#"R)  
for(int i=0;i<nEndPos.length-1;i++) sg2C_]i,H  
{ &ivIv[LV  
nEndPos = nStartPos[i+1]; eC39C2q\  
} =+L>^w#6=  
nEndPos[nEndPos.length-1] = nFileLength; qprOxP r  
} 8UcT? Zp  
} |Wgab5D>V  
?C{N0?[P-  
ZM.g +-9  
//启动子线程 # 0 (\s@r.  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; }>:X|4]  
for(int i=0;i<nStartPos.length;i++) TK>}$.c%+  
{ ;v'Y' !-J  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), OY#_0p)i  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), z~5'p(|@f  
nStartPos,nEndPos,i); pk4&-iu9  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Jp#cFUa t  
fileSplitterFetch.start(); `QF|> N  
} `!8Z"xD  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), mx4*zj  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); <i6MbCB  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 19t*THgq  
nEndPos = " + nFileLength); 3Cl9,Z"&6$  
// fileSplitterFetch[nPos.length-1].start(); Uf<vw3  
8(;i~f:bCW  
9 JtG&^*  
//等待子线程结束 OXB-.<  
//int count = 0; !/zj7z !  
//是否结束while循环  B" z5j  
boolean breakWhile = false; hH/ O2  
g1|c?#fwo  
UXJl;M b  
while(!bStop) MO/N*4U2  
{ n}?G!ySg  
write_nPos(); 7A6sSfPUy  
Utility.sleep(500); }b(e  
breakWhile = true; J5T#}!f  
BxU1Q&  
xTZ5q*Hqx  
for(int i=0;i<nStartPos.length;i++) uSJP"Lw  
{ [  _$$P*  
if(!fileSplitterFetch.bDownOver) 1 %`:8  
{ k]iS3+nD  
breakWhile = false; ~=ktFuEa  
break; bYc qscW  
} HWBom8u0  
} O2dgdtm  
if(breakWhile) :bDA<B6bb  
break; S/;Y4o  
4vS!99v)  
>6 #\1/RP  
//count++; ]Dg0@Y  
//if(count>4) bn35f<+  
// siteStop(); M(uB ;Te  
} 9a%@j ]  
nW_  
v!xrUyN~m  
System.err.println("文件下载结束!"); |Ze}bM=N  
} BkfBFUDQ  
catch(Exception e){e.printStackTrace ();} !e `=UZe1  
} <GRf%zJ  
9A(K_d-!H  
+GU16+w~E  
//获得文件长度 \k_3IP?o=  
public long getFileSize() |/;5|  z  
{ 4?& a?*M  
int nFileLength = -1; M3 u8NRd5|  
try{ %U7f9  
URL url = new URL(siteInfoBean.getSSiteURL()); 4/WCs$  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); QB,ad   
httpConnection.setRequestProperty("User-Agent","NetFox"); 2v1&%x:y#  
8-ssiiJ}gh  
*XO KH+_u  
int responseCode=httpConnection.getResponseCode(); MlE~ gCD  
if(responseCode>=400) h';v'"DoW`  
{ e&4u^'+K  
processErrorCode(responseCode); CD[=z)<z{  
return -2; //-2 represent access is error G\ZRNb  
} gDNW~?/  
66^t[[  
^)l@7XxD  
String sHeader; @|Bp'`j%J  
eE%yo3  
_|:bac8pL  
for(int i=1;;i++) H> iZVE  
{ nV*sdSt  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); iQ C&d_#  
//Utility.log(in.readLine()); *8H;KGe=  
sHeader=httpConnection.getHeaderFieldKey(i); 9z/_`Xd_  
if(sHeader!=null) 3uG5b8?  
{ ZMg9Qt  
if(sHeader.equals("Content-Length"))  7`@?3?  
{ 0\nhg5]?  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 5yi q#  
break; .@-]A   
} SkRQFm0a~  
} RmV/wY  
else d|+jCTKS  
break; _hL4@ C  
} gr{Sh`Cm-  
} 3|r!*+.  
catch(IOException e){e.printStackTrace ();} p Y>-N  
catch(Exception e){e.printStackTrace ();} G0Tc}_o<Y  
:vyf-K 74M  
b\m( 0/x  
Utility.log(nFileLength); %]$p ^m  
@SG"t,5s  
6FIoWG"x  
return nFileLength; R bc2g"]  
} FXEfD"  
D K_v{R  
u!Nfoq&'u  
//保存下载信息(文件指针位置) V?dK*8s  
private void write_nPos() g] C3 lf-  
{  ^-*Tn  
try{ ixHZX<6zYT  
output = new DataOutputStream(new FileOutputStream(tmpFile)); GiO#1gA  
output.writeInt(nStartPos.length); 9OT4j Am  
for(int i=0;i<nStartPos.length;i++) )TG0m= *  
{ LNxE-Dp  
// output.writeLong(nPos); ]l7\Zq  
output.writeLong(fileSplitterFetch.nStartPos); )u/ ^aK53^  
output.writeLong(fileSplitterFetch.nEndPos); 02#Iip3t  
} maEpT43f  
output.close(); 3=|2Gs?ut  
} b<V./rWIB  
catch(IOException e){e.printStackTrace ();} jP.b oj_u*  
catch(Exception e){e.printStackTrace ();} lF"(|n"R  
} ~nc([%!=  
)'dH}3Ba  
[67E5rk-  
//读取保存的下载信息(文件指针位置) 6 %k+0\d  
private void read_nPos() :`^3MMLO  
{ bKJ7vXC05  
try{ yO,`"Dc_0  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); S<]a@9W  
int nCount = input.readInt(); 4'hcHdL9   
nStartPos = new long[nCount]; ig _<kj;Vd  
nEndPos = new long[nCount]; OPt;G,$ta  
for(int i=0;i<nStartPos.length;i++) IgR"eu U  
{ {AL9o2  
nStartPos = input.readLong(); akCo+ @  
nEndPos = input.readLong(); S{(p<%)[  
} q(tG bhQ  
input.close(); P(gVF |J?  
} :htq%gPex9  
catch(IOException e){e.printStackTrace ();} O:=|b]t  
catch(Exception e){e.printStackTrace ();} J1Ki2I=  
} S O:V|Tfj  
^N2M/B|0  
BS,5W]ervE  
private void processErrorCode(int nErrorCode) dGD^op,6g  
{ DEQE7.]3q  
System.err.println("Error Code : " + nErrorCode); CL'Xip')T  
} x gT~b9  
hn\Q6f+  
K _+;"G  
//停止文件下载 oSA*~N:  
public void siteStop() b801O F  
{ LUDJPIk  
bStop = true; |~b R.IA  
for(int i=0;i<nStartPos.length;i++) DMcxa.Sd!  
fileSplitterFetch.splitterStop(); dbuJ~?D,  
6+B{4OY  
" $IXZ  
} =i^<a7M~  
} 4,F3@m:<  
//负责部分文件的抓取 Cq*}b4^;  
**FileSplitterFetch.java 9kX=99kf[  
*/ =e!l=d|/  
package NetFox; )dIfr  
g?[& 0r1  
Ph+X{|  
import java.io.*; z(` }:t  
import java.net.*; bA<AG*  
\aVY>1`  
z'oiyXEE3  
public class FileSplitterFetch extends Thread { ) {  
}uI7 \\S  
#3Ej0"A@-B  
String sURL; //File URL !H1tBg]5  
long nStartPos; //File Snippet Start Position rx6-~0!eI=  
long nEndPos; //File Snippet End Position A6NxM8ybn+  
int nThreadID; //Thread's ID Ed^uA+D  
boolean bDownOver = false; //Downing is over qQxA@kdd  
boolean bStop = false; //Stop identical V@ _-H gg  
FileAccessI fileAccessI = null; //File Access interface (e8G (  
]Q4PbW  
WfDX"rA  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException M,t*nG  
{ C3\E.u ?  
this.sURL = sURL; "7yNKO;W  
this.nStartPos = nStart; &`yOIX-H_  
this.nEndPos = nEnd; Gh2Q$w:  
nThreadID = id; @ <OO  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 H\| ]!8w5Z  
} V'"I9R'1  
K/2.1o;9  
{;&B^uz ]  
public void run() UIf ZPf=  
{ JS/M~8+Et  
while(nStartPos < nEndPos && !bStop) ) Ab6!"'  
{ q1f=&kGX~  
.B'UQ|NR  
7Y32p'  
try{ 1 @%B?  
URL url = new URL(sURL); BeI;#m0  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); p`:*mf  
httpConnection.setRequestProperty("User-Agent","NetFox"); gE@$~Q>M  
String sProperty = "bytes="+nStartPos+"-"; p"[O#*p  
httpConnection.setRequestProperty("RANGE",sProperty); kYxl1n v  
Utility.log(sProperty); rps(Jos_~  
a(@p0YpKT  
=9pw uH  
InputStream input = httpConnection.getInputStream(); Pknc[h},  
//logResponseHead(httpConnection); |As2"1_f  
bR`rT4.F  
JAlU%n?R  
byte[] b = new byte[1024]; U~*c#U"bh  
int nRead; iUIy,Y  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) @8=vFP'  
{ ,M) k7t:  
nStartPos += fileAccessI.write(b,0,nRead); _\dt?(m|  
//if(nThreadID == 1) <Zp^lDxa  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 20UqJM8 Ot  
} aXdf>2c{JD  
#e.jY_  
X*sr  
Utility.log("Thread " + nThreadID + " is over!"); wfxOx$]z K  
bDownOver = true; 4l&"]9D  
//nPos = fileAccessI.write (b,0,nRead); gEv->pc  
} !TP6=ks  
catch(Exception e){e.printStackTrace ();} ohrw\<xsu  
} g4:VR:o  
} }iilzE4oH#  
"v(G7*2  
a`H\-G  
//打印回应的头信息 FUaI2  
public void logResponseHead(HttpURLConnection con) +7Yu^&  
{ q*6q}s3n  
for(int i=1;;i++) JbE?a[Eg?  
{ E-~mOYea  
String header=con.getHeaderFieldKey(i); iOT)0@f'  
if(header!=null) [J0*+C9P*  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ^ <qrM  
Utility.log(header+" : "+con.getHeaderField(header)); #B @X  
else i`prv&  
break; VpkD'<G  
} aSOU#Csx  
} J&M1t#UN  
% f2<U;ff  
iQt!PMF.  
public void splitterStop() b5A Gk  
{ F:%^&%\  
bStop = true; M h`CP  
} ?75\>NiR  
dQ:?<zZ  
K7IyCcdB  
} Kb}MF9?:e  
K~c^*;F  
6Wj@r!u  
/* AD^X(rW  
**FileAccess.java coDj L.u  
*//文件访问(定位,写) 4d!S#zx  
package NetFox; Nd`HB=ShJ  
import java.io.*; R0%?:! F  
P7z:3o.  
VS?dvZ1cC  
public class FileAccessI implements Serializable{ P: n#S%  
D7)(D4S4  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 B4Q79gEh=  
RandomAccessFile oSavedFile; KiQ(XNx  
long nPos; q"S(7xWS  
8QV t, 'I  
< CDA"  
public FileAccessI() throws IOException j"5Pe  
{ xw?CMA  
this("",0); e1Ob!N-  
} ;4 ,'y  
[*<.?9n)or  
(vKI1^,  
public FileAccessI(String sName,long nPos) throws IOException  }mKwFVZ  
{ Zvxp%dES  
oSavedFile = new RandomAccessFile(sName,"rw"); dY8(nQG  
this.nPos = nPos; _R)&k%i}  
oSavedFile.seek(nPos); q0Xoj__c!A  
} _z q)0\  
1!!\+ c2*  
RU6KIg{H  
public synchronized int write(byte[] b,int nStart,int nLen) Jy9bY  
{ !2z!8kI  
int n = -1; R2l[Q){!  
try{ rJ DnuR  
oSavedFile.write(b,nStart,nLen); [[w2p  
n = nLen; *8PN!^  
} i3\~Qj;1  
catch(IOException e) tw=K&/@^O  
{ a5a1'IVq  
e.printStackTrace (); I:i<>kG  
} L1wZU,o  
ym\(PCa5`  
l7z 6i*R  
return n; z>G;(F2  
} SG:bM7*1'  
ACb/ITu  
lyyX<=E{)  
} FPF6H puV  
ZHCr2^w6  
P/MM UmO  
/* cx{T '1  
**SiteInfoBean.java X"j>=DEX  
*/ d8E,o7$m  
package NetFox; |g<*Rk0  
dv , C6t2  
?g3 ]~;#  
public class SiteInfoBean { fywvJ$HD]L  
k9mi5Oc  
*_1[[~Aw  
private String sSiteURL; //Site's URL hL!QLiF:  
private String sFilePath; //Saved File's Path zmiZ]uq  
private String sFileName; //Saved File's Name tiYOMA  
private int nSplitter; //Count of Splited Downloading File vZu~LW@1  
-f?Ah  
^,TTwLy- t  
public SiteInfoBean() R-  
{//nSplitter的缺省值为5 =1Z;Ma<;  
//default value of nSplitter is 5 Z19m@vMsIP  
this("","","",5); 2+.18"rvi  
} "ZT.k5Z  
_y vLu j  
OR4!YVVQ  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ,gMy@  
{ (#|{%4g@>  
sSiteURL= sURL; rk|a5-i  
sFilePath = sPath; fxgU~'  
sFileName = sName; \G>ZkgU  
this.nSplitter = nSpiltter; iY~rne"l  
g$FEEDF  
5wT>N46UX  
} }mZV L~|V  
yfEb  
W%o|0j\1GU  
public String getSSiteURL() cSK&[>i)4  
{ 0y~<%`~  
return sSiteURL; .VM3D0aV  
} ghAi{@s$)  
Hx2En:^Gf  
I%"'*7 U  
public void setSSiteURL(String value) eEl.. y  
{ T5|c$doQ  
sSiteURL = value; a}gk T]  
} 8;8c"'Mn  
q'G,!];qL  
\NK-L."[  
public String getSFilePath() uLk]LT  
{ Qx)Jtb0`V  
return sFilePath; fP[& a9l  
} !%PWig-  
|c2 xy  
<G ~>~L.E  
public void setSFilePath(String value) $bsH$N#6T  
{ {G3i0 r  
sFilePath = value; rNlW7 Y  
} E4i0i!<z  
u6Je@e_!  
--fFpM3EvS  
public String getSFileName() 1J}8sG2`  
{ y(a!YicA?  
return sFileName; eV7 u*d?  
} ;%!B[+ut"  
DCQ^fZ/  
*5V Xyt2  
public void setSFileName(String value) %gd(wzco  
{ '91".c,3?  
sFileName = value; F$MX,,4U  
} @5VV|Wt=  
<>Y?v C  
&dR=?bz-A  
public int getNSplitter() -#s [F S  
{ j_cs;G: "  
return nSplitter; U@F)2?  
} "TS  
H'=(`  
VDbI-P&c  
public void setNSplitter(int nCount) P"_$uO(5x  
{ YB,t0%vTJw  
nSplitter = nCount; Sw[{JB;y,  
} ,Hn^z<f   
} p'94SXO_  
RA O`i>@  
D@oCP =m<  
/* {ZsdLF#  
**Utility.java 0?0Jz  
*/ 'CR)`G_'[  
package NetFox; ve6w<3D@  
!CUoHTmB  
nBItO~l  
public class Utility { XORk!m|  
51B lM%  
kAA>FI6  
public Utility() w5=tlb  
{ ^|MjJsn  
[ ho (z30k  
~b~2 >c9  
} m Lk(y*  
|JF@6  
//线程睡眠 ~lAKJs#{  
public static void sleep(int nSecond) % ps$qB'  
{ "= / f$Xf  
try{ 9=X)ung9  
Thread.sleep(nSecond); c]-*P7W  
} }J:+{4Yn  
catch(Exception e) Hu3wdq  
{ *J|(jdu7  
e.printStackTrace (); ``VW;l{  
} @=j WHS  
} 7nq3S  
1BHG'y  
//日志 yifY%!@Xu  
public static void log(String sMsg) 7JJ/D4uT  
{ =3ioQZ^Vz  
System.err.println(sMsg); #>=j79~  
} NEt1[2X%  
?<Wb@6kh`  
9^FziM  
public static void log(int sMsg) 0& >H^  
{ (Rt7%{*  
System.err.println(sMsg); HB+|WW t>  
} 7\]E~/g  
} Q\ /uKQ  
ZF7IL  
L(T12s  
/* *]hBGr#6  
**TestMethod.java qyC=(v  
*/ WQ yLf;!Lz  
package NetFox; o8e?J\?  
HK\~Qnq  
8UC xn f#  
public class TestMethod { _@S`5;4x  
ljl^ GFo  
lj+u@Z<xA  
public TestMethod() .ERO|$fv  
{ ///xx/weblogic60b2_win.exe F}Vr:~  
try{ "-@[R  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); AJ#Nenmj  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); X7k.zlH7T  
SiteFileFetch fileFetch = new SiteFileFetch(bean);  hI9  
fileFetch.start(); .bBdQpF-  
} W9NX=gE4  
catch(Exception e){e.printStackTrace ();} Q.K,%(^;a  
%HrAzM.QBF  
F:x [  
}  H"A7Zo  
l;o1 d-n]  
2-Y<4'>  
public static void main(String[] args) x _c[B4Tw  
{ jy-{~xdg[  
new TestMethod(); oudxm[/U  
} #g6.Glz3  
} iY21Ql%  
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