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http断点续传简单实现(java)

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/* z$d<ep{6  
**SiteFileFetch.java \X! NoF  
*/ 7TI6EKr  
package NetFox; Z1v~tqx  
import java.io.*; %\|{_]h}y  
import java.net.*; QY<5o;m`  
'+vmC*-I(  
Rrl  
public class SiteFileFetch extends Thread { ZQ*Us*9I  
d+5~^\lV  
:?y Ma$  
SiteInfoBean siteInfoBean = null; //文件信息Bean d:^B2~j  
long[] nStartPos; //开始位置 H[OgnnM  
long[] nEndPos; //结束位置 IoK/2Gp  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 }a9G,@:k  
long nFileLength; //文件长度 "lt5gu!`u  
boolean bFirst = true; //是否第一次取文件 :/Es%z D  
boolean bStop = false; //停止标志 >mR8@kob<  
File tmpFile; //文件下载的临时信息 34N~<-9AY  
DataOutputStream output; //输出到文件的输出流 wYV>Qd Z  
uPYH3<  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) [.Kp/,JY  
public SiteFileFetch(SiteInfoBean bean) throws IOException h9}*_qc&kV  
{ (C).Vj~  
siteInfoBean = bean; W\w#}kY  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 4*E5@{D  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); pWv1XTs@t:  
if(tmpFile.exists ()) q TN)2G  
{ [Y@>,B!V  
bFirst = false; H|wP8uQC  
read_nPos(); yf8kBT:&S  
} "8cI]~ V  
else &|RTLGwX  
{ YOrq)_ l  
nStartPos = new long[bean.getNSplitter()]; 7:b.c  
nEndPos = new long[bean.getNSplitter()]; Sl^PELU  
} ZE_  
hLk6Hqr7  
^eO/?D8~h  
b.\xPb  
}  O&|<2Qr  
-<5{wQE;|  
GQCdB>   
public void run() %8xRT@Q  
{  |Nj6RB7  
//获得文件长度 MpZ\ j  
//分割文件 Vr( Z;YO  
//实例FileSplitterFetch 'x"(OdM:[  
//启动FileSplitterFetch线程 2=0HQXXrq  
//等待子线程返回 'U`;4AN  
try{ w=rD8 @  
if(bFirst) S1mMz i  
{ vW vu&3tx  
nFileLength = getFileSize(); DU]KD%kl  
if(nFileLength == -1) VHl1f7%@H  
{ A%$~  
System.err.println("File Length is not known!"); 7C3YVm6g  
} blIMrP%  
else if(nFileLength == -2) Dat',5  
{ |Rhqi  
System.err.println("File is not access!"); Q% d1n*;+  
} i 61k  
else 4:N*C7 P  
{ T :m" eD;  
for(int i=0;i<nStartPos.length;i++) CPRVSN0b{4  
{ { $yju_[  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); u5glKE  
} h ! R=t  
for(int i=0;i<nEndPos.length-1;i++) dpNERc5  
{ p@4GI[4  
nEndPos = nStartPos[i+1]; zhFm2  
} fbOqxF"?we  
nEndPos[nEndPos.length-1] = nFileLength; 25{_x3t^  
} 2@GizT*mA  
} nR*' 3  
Km%L1Cd]  
.#|?-5q/iN  
//启动子线程 Q!U}  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; PS[ C!s&KE  
for(int i=0;i<nStartPos.length;i++) }58MDpOF1  
{ 8j3Y&m4^  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), NM![WvtjW  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), zB`woI28  
nStartPos,nEndPos,i); s:"Sbml  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); xSK#ovH2  
fileSplitterFetch.start(); W [K.|8ho  
} d,JDfG)  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Y-YuY  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); g""GQeR  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", \'*M }G  
nEndPos = " + nFileLength); K SO D(  
// fileSplitterFetch[nPos.length-1].start(); y5m2u8+  
l&qCgw  
[{BY$"b#:  
//等待子线程结束 bD:0k.`  
//int count = 0; g]2L[4  
//是否结束while循环 l$/lbwi%  
boolean breakWhile = false; Q^rR}Ws  
Hy[: _E  
M %!;5  
while(!bStop) ~S\L(B(  
{ % |D)%|Z  
write_nPos(); oYStf5  
Utility.sleep(500); BU/A\4xQ,Y  
breakWhile = true; `;;l {8  
%g.cE}^  
uy3<2L#.  
for(int i=0;i<nStartPos.length;i++) Ws@'2i\;  
{ SNH 3C1  
if(!fileSplitterFetch.bDownOver) #Q^" .#  
{ }a6t<m`V  
breakWhile = false; ~!r;?38V`  
break; NSB6 2  
} SXOAa<u5  
} ^1bslCe   
if(breakWhile) Kx] SiejJ  
break; M[YFyM(  
A:r?#7 Ma  
+C{-s  
//count++; eNAxVF0  
//if(count>4) ?s^3 o{!<W  
// siteStop(); ~dRstH7u  
} cA q3Gh  
SE]5cJ'>  
4F~^RR"  
System.err.println("文件下载结束!"); EaO@I.[  
} DdgiY9a.  
catch(Exception e){e.printStackTrace ();} 6&eXQl  
} #lLUBJ#:  
]zSFX =~(S  
g8%O^)d=>  
//获得文件长度 &P|[YP37_  
public long getFileSize() -o6rY9\_!  
{ :BF? r  
int nFileLength = -1; [fa4  
try{ 'cXdc  
URL url = new URL(siteInfoBean.getSSiteURL()); UUJQc ~=  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); != ,4tg`  
httpConnection.setRequestProperty("User-Agent","NetFox"); "S%t\  
EX`P(=zD  
sV  
int responseCode=httpConnection.getResponseCode(); .9qK88fUR  
if(responseCode>=400) tUJRNEg  
{ uPA ( 1  
processErrorCode(responseCode); |/*Pimk  
return -2; //-2 represent access is error F`nQS&y  
} ;[sW\Ou  
S }`sp[6  
J/?Nf2L4  
String sHeader; // o.+?S  
"n!yK  
)S)L9('IxT  
for(int i=1;;i++) tF0jH+7J-  
{ `@h|+`h  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); +tqErh?Al  
//Utility.log(in.readLine()); aKbmj  
sHeader=httpConnection.getHeaderFieldKey(i); %T{]l;5  
if(sHeader!=null) HB/V4ki  
{ WVbrbs4  
if(sHeader.equals("Content-Length"))  Z.6dL  
{ hi0HEm\  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ' [ 4;QYw  
break; G21o @38e  
} F1t(P 8  
} z*eBjHbF  
else FM@iIlY"  
break; K T}  
} 1PkCWRpR  
} @^W`Yg)C  
catch(IOException e){e.printStackTrace ();} bV_nYpo  
catch(Exception e){e.printStackTrace ();} |@Tga_0p  
'-;[8:y.  
e<L@QNX  
Utility.log(nFileLength); Ma[EgG  
{3tzr;c?  
e`D}[G#  
return nFileLength; g>@JGzMLP  
} 1sQIfX#2f  
$<^t][{  
Dm>"c;2  
//保存下载信息(文件指针位置) zH8E,)  
private void write_nPos() fd\RS1[  
{ %z><)7  
try{ iQwQ5m!d &  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Eah6"j!B8n  
output.writeInt(nStartPos.length); OU[<\d  
for(int i=0;i<nStartPos.length;i++) *U?O4E9  
{ wHc my  
// output.writeLong(nPos); HGDrH   
output.writeLong(fileSplitterFetch.nStartPos); gb ga"WO  
output.writeLong(fileSplitterFetch.nEndPos); :]^e-p!z  
} ~&?bU]F  
output.close(); x*Lt]]A  
} +&Ld` d!n  
catch(IOException e){e.printStackTrace ();} tgK I  
catch(Exception e){e.printStackTrace ();} }htjT/Nm  
} dj0; tQ=C  
>H2`4]4]  
vT'Bs;QR  
//读取保存的下载信息(文件指针位置) Aw o)a8e  
private void read_nPos() (yOkf-e2y  
{ ~C.*Vc?|  
try{ 0+1wi4wy/  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); rl*O-S/  
int nCount = input.readInt(); O !L`0 =%c  
nStartPos = new long[nCount]; '|C3t!H`  
nEndPos = new long[nCount]; ly[LF1t   
for(int i=0;i<nStartPos.length;i++) )D)5 `n)  
{ ^QB[;g.O  
nStartPos = input.readLong(); D6sw"V#  
nEndPos = input.readLong(); |?`5~f  
} ;?-AFd\i  
input.close(); hvd}l8  
} Y ::0v@&(  
catch(IOException e){e.printStackTrace ();} H"C'<(4*\  
catch(Exception e){e.printStackTrace ();} ]n22+]D  
} `BPTcL<W  
%`vzQt`>  
<qCa 9@Ea  
private void processErrorCode(int nErrorCode) <AHpk5Sn{  
{ uy'ghF  
System.err.println("Error Code : " + nErrorCode); 5Wt){rG0Z  
} 5gszAvOO  
Ac7^JXh%  
kX 1}/l  
//停止文件下载 iTVe8eI  
public void siteStop() I$n= >s  
{ Y Y:Bw W:  
bStop = true; Zo9<96I&  
for(int i=0;i<nStartPos.length;i++) JE?p'77C  
fileSplitterFetch.splitterStop(); V|7YRa@  
j]a$RC#  
vh9* >[i  
} \INH[X#>  
} )*|/5wW1  
//负责部分文件的抓取 j =_rUc'Me  
**FileSplitterFetch.java K~x,so  
*/ &K)8  
package NetFox; weitDr6  
)Nv1_en<!  
VSj!Gm0LB  
import java.io.*; ~xH&"1  
import java.net.*; !XA3G`}p6s  
x%P|T3Qy5  
"(koR Q  
public class FileSplitterFetch extends Thread { fn#8=TIDf  
}kbSbRH43  
[\uR3$j#  
String sURL; //File URL g|=_@ pL  
long nStartPos; //File Snippet Start Position 73WSW/^F  
long nEndPos; //File Snippet End Position H#- 3  
int nThreadID; //Thread's ID +>w]T\[1~  
boolean bDownOver = false; //Downing is over ]6&NIz`:,  
boolean bStop = false; //Stop identical W+nu=iQ!  
FileAccessI fileAccessI = null; //File Access interface r );R/)&  
e5 =d Ev  
9N ]Xa  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException wN 2+3LY{  
{ (z?HyxRT  
this.sURL = sURL; gwZ<$6  
this.nStartPos = nStart; &4'< {  
this.nEndPos = nEnd; 'nJF:+30ZH  
nThreadID = id; Ae)xFnuq3  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 4 23zX6  
} CU$kh z"  
aM^iDJ$>  
k15vs  
public void run() )fH Q7  
{ :fRXLe1=  
while(nStartPos < nEndPos && !bStop) qZoDeN-CC  
{ UNI< r  
I Mgd2qIC  
`h}eP[jA  
try{ yu?5t?vf  
URL url = new URL(sURL); XGlt^<`  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Fc[KIG3@  
httpConnection.setRequestProperty("User-Agent","NetFox"); Iw1Y?Qia  
String sProperty = "bytes="+nStartPos+"-"; x^eu[olN  
httpConnection.setRequestProperty("RANGE",sProperty); B.<SC  
Utility.log(sProperty); a(Y'C`x  
NGra/s,9 |  
~{c ?-qb  
InputStream input = httpConnection.getInputStream(); ]5W$EvZ9)  
//logResponseHead(httpConnection); lwnO  
WSThhI  
+,Dc0VC?  
byte[] b = new byte[1024]; x_PO;  
int nRead; t@RYJmW  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) St=nf\P&F  
{ ;%|im?  
nStartPos += fileAccessI.write(b,0,nRead); e r" w{  
//if(nThreadID == 1) +qxPUfN  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); (5a73%>@  
} MsB >3  
fV:15!S[  
tobE3Od4  
Utility.log("Thread " + nThreadID + " is over!"); LvG.ocCG  
bDownOver = true; [f6uwp  
//nPos = fileAccessI.write (b,0,nRead); #mH@ /6,#[  
} vwR_2u  
catch(Exception e){e.printStackTrace ();} B6XO&I1c  
} tMr7d  
} k(Yz2  
xh6(~'$  
=;Id["+  
//打印回应的头信息 0SpB 2>_  
public void logResponseHead(HttpURLConnection con) h!"2Ux3!x  
{ 8K8u|]i  
for(int i=1;;i++) 3 qYGEhxv  
{ Z[vx0[av&  
String header=con.getHeaderFieldKey(i); EIi<g2pM(  
if(header!=null) %lKw+D  
//responseHeaders.put(header,httpConnection.getHeaderField(header));  %zavSm"  
Utility.log(header+" : "+con.getHeaderField(header)); S :HOlJze  
else :]"5UY?oF  
break; {1GJ,['qL  
} ;qx#]Z0 <  
} 8&QST!JGSX  
C|{Sj`,XG  
R!VfTAv  
public void splitterStop() :cpj{v;s  
{ $+eeE  
bStop = true; 37bMe@W  
} Iil2R}1  
WR+j?Fcf  
Wzq W1<*`  
} 5C w( 4.  
p^l#Wq5  
uH_KOiF  
/* dg D-"-O  
**FileAccess.java mY|c7}>V;  
*//文件访问(定位,写) sA0 Ho6  
package NetFox; zI88IM7/  
import java.io.*; ! FcGa  
^0,}y]5p  
glAS$<  
public class FileAccessI implements Serializable{ T2{e 1 =Z7  
V:0IBbh)w  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 0 _!0\d#c  
RandomAccessFile oSavedFile; 7KtU\u  
long nPos; "+DA)K  
/4{WT?j  
ITPE2x  
public FileAccessI() throws IOException ?o<vmIge  
{ z$^d_)  
this("",0); $-_" SWG.  
} J%bNt)K}  
\ %-<O  
BRFsw`c  
public FileAccessI(String sName,long nPos) throws IOException I=`?4%  
{ &9jJ\+:7  
oSavedFile = new RandomAccessFile(sName,"rw"); -:}vf?  
this.nPos = nPos; VPCI5mS_  
oSavedFile.seek(nPos); IRW0.'Dn  
} b1xE;0uR  
Y;af|?U*6:  
KFM[caKeJO  
public synchronized int write(byte[] b,int nStart,int nLen) q 4BXrEOw  
{ &+9 ;  
int n = -1; &oL"AJU  
try{ xvGYd,dlK  
oSavedFile.write(b,nStart,nLen); z/Lb1ND8  
n = nLen; * :"*'  
} YznL+TD  
catch(IOException e) _/[qBe  
{ +|?a7qM  
e.printStackTrace (); &BVUK"}P  
} e\)%<G5  
ui]iO p  
q NGR6i  
return n; 4S(G366  
} T! }G51  
/N0mF< P  
+o+f\!  
} K#FD$,c~  
L1IF$eC  
1$Up7=Dr=  
/* eDd& vf  
**SiteInfoBean.java #y\O+\4e  
*/ &Vj @){  
package NetFox; $.,PteYK  
Uo3  
qw+ 7.h#V  
public class SiteInfoBean { ft"-  
@Y~gdK  
y)r`<B  
private String sSiteURL; //Site's URL o*T?f)_[p  
private String sFilePath; //Saved File's Path .M6. ]H  
private String sFileName; //Saved File's Name GTs,?t16/  
private int nSplitter; //Count of Splited Downloading File tmGhJZ2j  
GEPWb[Oa  
`n+uA ~  
public SiteInfoBean() !&%KJS6p4  
{//nSplitter的缺省值为5 c<13r=+  
//default value of nSplitter is 5 kn#?+Q  
this("","","",5); 9WHE4'Sa  
} l4gH]!/@  
q\tr&@4iC  
/OKp(u;)z  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) VnuG^)S  
{ %+r(*Q+0$f  
sSiteURL= sURL; ^;II@n i  
sFilePath = sPath; hC-uz _/3  
sFileName = sName; hu-]SGb6  
this.nSplitter = nSpiltter; hl]d99Lc  
Dw=L]i :0v  
#kQ! GMZH  
} TjpyU:R,&|  
IO7z}![V;  
DzC`yWstP  
public String getSSiteURL() q~>!_q]FE  
{ FC 8<D  
return sSiteURL; zB m~J%  
} Vc\g"1 x  
uVYn,DB`  
:b9#e g  
public void setSSiteURL(String value) <B%wq>4S  
{ b'( AVA  
sSiteURL = value; Ioe.[&o6B  
} ]xf89[;0  
\m`IgP*  
ErN[maix#  
public String getSFilePath() (R=ZI  
{ #h ud_  
return sFilePath; ,):aU  
} _Q:ot'(~0-  
P]"@3Z&w  
=Vh]{ y~$  
public void setSFilePath(String value) OL1xxzo  
{ $7X;FmlG&  
sFilePath = value; *Y1s4FXu2  
} do`'K3a"  
Ov" wcJ  
Wz^;:6F  
public String getSFileName() oD%n}  
{ D~inR3(}  
return sFileName; ~N /%R>(v  
} Sh;`<Ggi~  
%X\J%Fj  
QM!UMqdj  
public void setSFileName(String value) yS)k"XNb  
{ wgDAb#Zuk  
sFileName = value; 9X[378f+(  
} !yg &zzP*  
VI3fvGHat{  
f$</BND  
public int getNSplitter() &tkPZ*}#1  
{ s"7FmJ\7rw  
return nSplitter; *K>2B99TXu  
} 2U%t  
D~qi6@Ga  
nUY)Ln I  
public void setNSplitter(int nCount) ]Vf p,"op  
{ ym p*:lH(  
nSplitter = nCount; Bl)D/  
} '>OEQU5-  
} )1 @v<I  
$_%  
+VIEDV+   
/* [p\xk{7Y  
**Utility.java %AV3eqghCg  
*/ UB] tKn  
package NetFox; ,>g( %3C  
daY0;,>  
HJr*\%D}1  
public class Utility { MPp:EH  
FpttH?^  
6 y"r '  
public Utility() h*4wi.-  
{ "% i1zQo&  
$sL+k 'dY  
3b?-83a  
} .&=\ *cZc  
xR'd}>`  
//线程睡眠 -Hi_g@i*XW  
public static void sleep(int nSecond) KJn 3&7  
{ a Sm</@tO&  
try{ yokZ>+jb  
Thread.sleep(nSecond); AzGbvBI&V  
} rI)&.5^  
catch(Exception e) hAi'|;g  
{ fk#Ggp<  
e.printStackTrace (); 4P2p|Gc3  
} ),<h6$  
} nP=/XiCj  
a$"Z\F:x  
//日志 4/o9K*M+  
public static void log(String sMsg) 54JI/!a  
{ p<VW;1bt5  
System.err.println(sMsg); $ z+ =lF  
} Z\-Gr 2k  
7|m{hSc  
8Z@O%\1x6  
public static void log(int sMsg) X7aj/:fXe  
{ Yv*i69"  
System.err.println(sMsg); "| oW6@  
} (yu0iXZY  
} p8y<:8I  
+'e3YF+'  
?s0")R&  
/* n[-d~Ce2{  
**TestMethod.java QK~>KgVi  
*/ I#yd/d5^  
package NetFox; wS2N,X/Y  
u<@ 55k  
V6<Ki  
public class TestMethod { !OH'pC5  
BD ,3JDqT  
51%<N\>/4  
public TestMethod() D@mqfi(x  
{ ///xx/weblogic60b2_win.exe t/"9LMKs?  
try{ ht)KS9Xu  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); <RkJ 7Z^  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); is- {U? -  
SiteFileFetch fileFetch = new SiteFileFetch(bean); v2#qs*sW8  
fileFetch.start(); Zfr?(y+3  
} * 8D(Lp1  
catch(Exception e){e.printStackTrace ();} vCR\lR+  
TwE&5F*  
Lj3q?>D*^6  
} [h :FJ  
I'cM\^/h  
B gG+  
public static void main(String[] args) HQ|{!P\/?U  
{ LZ9IE>sj  
new TestMethod(); 6~+?DIc  
} *Oe;JqQkK  
} 7w"YCRKh  
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