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http断点续传简单实现(java)

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/* Ku;8Mx{  
**SiteFileFetch.java G/?j$T  
*/ c7/fQc)h4d  
package NetFox; 'DCB 7T8  
import java.io.*; [p 8fg!|  
import java.net.*; d>jRw  
T`r\yl}  
ZsL-vlv  
public class SiteFileFetch extends Thread { Q=.j>aM+_  
R\>=}7  
.6y(ox|LL  
SiteInfoBean siteInfoBean = null; //文件信息Bean k+As#7V  
long[] nStartPos; //开始位置 t zSg`7H!  
long[] nEndPos; //结束位置 ?KXgG'!!  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 & <Jvaf_=  
long nFileLength; //文件长度 "jAEZ  
boolean bFirst = true; //是否第一次取文件 .> |]Lo(=l  
boolean bStop = false; //停止标志 Y )9]I6n7  
File tmpFile; //文件下载的临时信息 QTuj v<|  
DataOutputStream output; //输出到文件的输出流 uJ>_ 2  
= ms o1  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) Czt>?8x`  
public SiteFileFetch(SiteInfoBean bean) throws IOException ~0ZLaiJ  
{ ,?>:Cdz4  
siteInfoBean = bean; te8lF{R  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); l@nG?l #  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 7|$ H}$  
if(tmpFile.exists ()) x\!Uk!fM  
{ jBnvu@K"  
bFirst = false; x#&%lJT  
read_nPos(); rw]*Nxgr  
} ]{E{ IW8  
else qC$h~Epp4  
{ ^fbw0  
nStartPos = new long[bean.getNSplitter()]; <P)0Yu  
nEndPos = new long[bean.getNSplitter()]; J3#  
} ,K[}Bz  
parc\]M  
AHtLkfr(r  
Q7@ m.w%`  
} qaN%&K9F8  
oB]   
z\Y-8a.]  
public void run() F!qt#Sw!\  
{ 4e5 5  
//获得文件长度 H:&|q+K=#  
//分割文件 0G"I}Jp{  
//实例FileSplitterFetch ]aVFWzey  
//启动FileSplitterFetch线程 d!]fou  
//等待子线程返回 V;t8v\  
try{ /?Fa<{  
if(bFirst) =#ls<Zo:  
{ no lLeRE1  
nFileLength = getFileSize(); ~i)IY1m"  
if(nFileLength == -1) vTF_`X  
{ ;*_U)th  
System.err.println("File Length is not known!"); I%fz^:[#<  
} y:N>t+'5  
else if(nFileLength == -2) ^9PB+mz  
{ "lJ [H=\  
System.err.println("File is not access!"); )./'`Mx?  
} @ I$;  
else tZn=[X~Vw@  
{ Z )f\^  
for(int i=0;i<nStartPos.length;i++) FtL{ f=  
{ } I;5yk,o  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ><Z`) }f  
} ;p}X]e l}  
for(int i=0;i<nEndPos.length-1;i++) D/=  AU  
{ auP6\kpMe  
nEndPos = nStartPos[i+1]; p .^#mN  
} (0/)vZc  
nEndPos[nEndPos.length-1] = nFileLength; drZ1D s  
} V`MV_zA2  
} 9e:}q O5)  
}R -azN;  
Q #%C)7)  
//启动子线程 @hE$x-TP0  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; HX]pcX^K  
for(int i=0;i<nStartPos.length;i++) umD[4aP~;  
{ A&~<qgBTp  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), FOU^Wcop%  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), :RnFRAcr  
nStartPos,nEndPos,i); E"P5rT  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ] EzX$T  
fileSplitterFetch.start(); ?/,sKF74i  
} dU~DlaEy(  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), H' [#x2  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); +|w-1&-  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Z=vzF0  
nEndPos = " + nFileLength); jBvZ>H+w~  
// fileSplitterFetch[nPos.length-1].start(); *qLOr6  
){.J`X5r  
IiV#V  
//等待子线程结束 (HUGgX"=  
//int count = 0; ;-koMD!2F  
//是否结束while循环 ;S FmbZ%~  
boolean breakWhile = false; lilKYrUmG  
fJ?$Z|  
]eJjffx  
while(!bStop) !:[kS1s>M  
{ tilL7  
write_nPos(); 79>8tOuo  
Utility.sleep(500); +r+H`cT@  
breakWhile = true; b7:B[7yK.x  
ms%Ot:uA  
o9:GKc  
for(int i=0;i<nStartPos.length;i++) F+`DfI]/m  
{ 3??*G8Yp  
if(!fileSplitterFetch.bDownOver) om"q[Tudc  
{ *Iu .>nw  
breakWhile = false; Zh WtY  
break; # Z*nc0C  
} a?IL6$z  
} K_J o^BZ  
if(breakWhile) Xj\SJ*  
break; o'3t(dyyH  
Xjal6e)[  
3huT T"G  
//count++; bm{L6D E  
//if(count>4) |xTf:@hgHf  
// siteStop(); ZcXqH7`r  
} U~SOHfZ%(  
=%:mZ@x'  
}@pe `AF^  
System.err.println("文件下载结束!"); _J51 :pi  
} HHbkR2H1  
catch(Exception e){e.printStackTrace ();} ms8PFu(f  
} r"a4 ;&mf  
}31z 35  
7^bO`  
//获得文件长度 %NbhR(  
public long getFileSize() 0;-S){  
{ {.We%{4V  
int nFileLength = -1; 1R/=as,R  
try{ 7/;Xt&  
URL url = new URL(siteInfoBean.getSSiteURL()); =W9;rQm  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); k!]Tg"]JAh  
httpConnection.setRequestProperty("User-Agent","NetFox"); wR;_x x  
]FLuiC  
W"mkNqH  
int responseCode=httpConnection.getResponseCode(); %$ ^yot  
if(responseCode>=400) Te"<.0~1  
{ _|MY/SN4A  
processErrorCode(responseCode); j.GpJDq  
return -2; //-2 represent access is error /tno`su;  
} 4QnJ;&~  
K5Fzmo a  
'|e5cW6z  
String sHeader; Dg_/Iu>OAE  
^P-!pK*  
3<x_[0v`K1  
for(int i=1;;i++) p&F=<<C  
{ P X](hc=  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); _4z>I/R>Z  
//Utility.log(in.readLine()); G! uQ|<(  
sHeader=httpConnection.getHeaderFieldKey(i); yZaQ{]"  
if(sHeader!=null) x3L3K/qMg  
{ $-VW)~Sl  
if(sHeader.equals("Content-Length")) R Nr=M^Zn  
{ l_LfVON  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); AA}M"8~2  
break; O{rgZ/4Au  
} Rww"Z=F  
} r+HJ_R,5A  
else &X^~%\F:2  
break; !+cRtCaA::  
} ru)%0Cyx  
} kTG}>I  
catch(IOException e){e.printStackTrace ();} n<7#?X7  
catch(Exception e){e.printStackTrace ();} M`umfw T  
H7)(<6b,z  
^HHJ.QR  
Utility.log(nFileLength); =5_8f  
7/(C1II.Q  
u~?]/-.TY  
return nFileLength; <;x+ ?j  
} dL")E|\\k  
~s{$&N  
oZ%t!Fl1  
//保存下载信息(文件指针位置) rQK2&37-,@  
private void write_nPos() tiwhG%?2  
{ Y( /VW&K&:  
try{ n$}c+1   
output = new DataOutputStream(new FileOutputStream(tmpFile)); a2iaP  
output.writeInt(nStartPos.length); jHB,r^:'  
for(int i=0;i<nStartPos.length;i++) bdqo2ZO  
{ lN1T\  
// output.writeLong(nPos); D?]aYCT  
output.writeLong(fileSplitterFetch.nStartPos); hGF:D#jyT  
output.writeLong(fileSplitterFetch.nEndPos); k+-u 4W   
} 6R@ v>}  
output.close(); G\TyXq_4  
} 8Md*9E#J("  
catch(IOException e){e.printStackTrace ();} <"CG%RGP  
catch(Exception e){e.printStackTrace ();} =Ze~6vS,  
} %Q}#x  
6ssZg@}nf{  
(XT^<#Ga  
//读取保存的下载信息(文件指针位置) VX&KGG.6  
private void read_nPos() +YhTb  
{ O" ['.b  
try{ +S|y)W8  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); E](Ood  
int nCount = input.readInt(); p=9G)VO  
nStartPos = new long[nCount]; 1h]Dc(Oc#=  
nEndPos = new long[nCount]; "xS",6Sy  
for(int i=0;i<nStartPos.length;i++) wamqeb{u  
{ " I`<s<  
nStartPos = input.readLong(); `-Gs*#(/  
nEndPos = input.readLong(); Tb}`]Y`X  
} (q*T.   
input.close(); )R{4"&&2  
} s<z{(a  
catch(IOException e){e.printStackTrace ();} 4jis\W}%L3  
catch(Exception e){e.printStackTrace ();} 6}Y^X  
} @<},-u  
ksm=<I"C  
EEn}Gw  
private void processErrorCode(int nErrorCode) ~|Gtm[9Ru  
{ !=cW+=1  
System.err.println("Error Code : " + nErrorCode); jbC7U9t7  
} CbS9fc&  
|,t#Au}61  
fVo)# Bj  
//停止文件下载 }RDhI1x[mk  
public void siteStop() 6P?   
{ ]t7<$L   
bStop = true; dB_\0?jJ-  
for(int i=0;i<nStartPos.length;i++) ]O7I7K  
fileSplitterFetch.splitterStop(); <8r%_ ']  
2}I1z_dq~  
C/_W>H_   
} O,9KhX+  
} b V;R}3)  
//负责部分文件的抓取 O>|Q Zd  
**FileSplitterFetch.java Q?7U iTZ  
*/ n`0}g_\q  
package NetFox; 3boINmX  
+Medu?K `  
|nz,srr~  
import java.io.*; 398}a!XM  
import java.net.*; gjL>FOe8u  
lXW.G  
WZ@nuK.39T  
public class FileSplitterFetch extends Thread { #\@*C=  
mWUQF"q8  
cl1h;w9s  
String sURL; //File URL M*8Ef^-U`t  
long nStartPos; //File Snippet Start Position /S\P=lcb  
long nEndPos; //File Snippet End Position 1/6G&RB  
int nThreadID; //Thread's ID vy1:>N?#5  
boolean bDownOver = false; //Downing is over JL`n12$m  
boolean bStop = false; //Stop identical *8,]fBUq  
FileAccessI fileAccessI = null; //File Access interface MBXumc_g  
sh:sPzQ%Jv  
ga6M8eOI  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ~e ]83?  
{ m}Kn!21  
this.sURL = sURL; 5RI"g f  
this.nStartPos = nStart; <.s[x~b\`  
this.nEndPos = nEnd; vDv:3qN7(  
nThreadID = id; a0CmCv2#  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ArbfA~jXB  
} cZZ-K?_  
FuLP{]Y+AM  
 9'\18_w  
public void run() :)cPc7$8  
{ Kt;h'?  
while(nStartPos < nEndPos && !bStop) _CciU.1k&,  
{ 536H*HdN  
(Pbdwzao  
\;.\g6zX  
try{ +P6q wh\v  
URL url = new URL(sURL); t]2~aK<]  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); tO)mKN+ (  
httpConnection.setRequestProperty("User-Agent","NetFox"); 2^E.sf$f  
String sProperty = "bytes="+nStartPos+"-"; e%U0^! 8  
httpConnection.setRequestProperty("RANGE",sProperty); vtv|H  
Utility.log(sProperty); 5yuj}/PZ  
xWU0Ev)4U  
D7olu29  
InputStream input = httpConnection.getInputStream(); &^{HD }/{b  
//logResponseHead(httpConnection); |t!kD(~r  
Vqb4 MWW  
L#M9!  
byte[] b = new byte[1024]; r|{h7'  
int nRead; (@p E  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) #K"jtAm  
{ !WR(H&uBr\  
nStartPos += fileAccessI.write(b,0,nRead); # ~} 26  
//if(nThreadID == 1) bezT\F/\  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); uv/I`[@HK8  
} F(Pe@ #)A  
Ky8sLm@  
im Zi7o  
Utility.log("Thread " + nThreadID + " is over!"); 3uZY.H+H  
bDownOver = true; ^j0Mu.+_  
//nPos = fileAccessI.write (b,0,nRead); V&eti2 &zO  
} UMma|9l(i  
catch(Exception e){e.printStackTrace ();} Gvb>M=9  
} wbyY?tH  
} +5JCbT@y  
l|/h4BJ'  
B-@6m  
//打印回应的头信息 Tu?+pz`h  
public void logResponseHead(HttpURLConnection con) e_kP=|u)g  
{ Nh^T,nv*l  
for(int i=1;;i++) {W)Kz_  
{ `M6!V  
String header=con.getHeaderFieldKey(i); E*:!G  
if(header!=null) 1j`-lD  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); M$B9?N6  
Utility.log(header+" : "+con.getHeaderField(header)); _*>bf G  
else +\fr3@Yc  
break; =!*e; L  
} j#f+0  
} N/p9Ws  
2%m H  
0~iC#lHO  
public void splitterStop() zcF~6-aQ  
{ eB%KXPhMm  
bStop = true; AE={P*g  
} %g5TU 6WP  
9TIyY`2!  
h3Nwxj~E  
} ms{:=L2$$  
Kyt.[" p  
1XSA3;ZEc  
/* &=Gz[1 L  
**FileAccess.java jr bEJ.  
*//文件访问(定位,写) W2D^%;mw  
package NetFox; GpMKOjVm|  
import java.io.*; AON";&dLq-  
g{.>nE^Sc5  
"w9LQ=mW  
public class FileAccessI implements Serializable{ ^VK-[Sz&  
Nwr.mtvh  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 :3^b>(W.  
RandomAccessFile oSavedFile; 11glFe  
long nPos; %<lfe<;^t  
(%}T\~`1z#  
0#pjfc `:  
public FileAccessI() throws IOException A[oLV"J6x5  
{ W$B&asO  
this("",0); *;"N kCf  
} bY|%ois4  
}__g\?Yf  
R7;SZo  
public FileAccessI(String sName,long nPos) throws IOException IfzHe8>  
{ veFl0ILd  
oSavedFile = new RandomAccessFile(sName,"rw"); Gtd!Y x  
this.nPos = nPos; )xX(Et6+`  
oSavedFile.seek(nPos); 9I0/KuZd O  
} :y==O4  
]sjYxe  
^m;dEe&@F  
public synchronized int write(byte[] b,int nStart,int nLen) dB+x,+%u+  
{ ?VrZM  
int n = -1; r5jiB L~  
try{ >!s =f  
oSavedFile.write(b,nStart,nLen); $/90('D  
n = nLen; f#_XR  
} +-&N<U  
catch(IOException e) F's($n  
{ ?Z0T9e<  
e.printStackTrace (); /=w9bUj5v  
} d"<Q}Ay  
^.5 L\  
E1IRb':  
return n; A ${b]  
} kq6S`~J^R  
@[#U_T- I  
;>QED  
} RqgH,AN  
|:$D[=  
y3F13 Z@%  
/* 3v)v92;  
**SiteInfoBean.java +(0Fab8g  
*/ 9r-]@6;  
package NetFox; TC[_Ip&  
lTJ1]7)  
o90SXa&l/  
public class SiteInfoBean { Qj5~ lX`W  
}ddwL  
xoF]r$sC8  
private String sSiteURL; //Site's URL -fw0bL%0  
private String sFilePath; //Saved File's Path h>-JXuN  
private String sFileName; //Saved File's Name DE|r~TQ  
private int nSplitter; //Count of Splited Downloading File aDFu!PLB{)  
3t22KY[`  
%ANo^~8  
public SiteInfoBean() .yE!,^j.gB  
{//nSplitter的缺省值为5 AN7WMX  
//default value of nSplitter is 5 OLJb8kO  
this("","","",5); $C0Nv Jf  
} /%C6e )7BL  
_+g5;S5  
"'h?O*V]u{  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) $gT+Ue|7  
{ jXvGL  
sSiteURL= sURL; p.^mOkpt  
sFilePath = sPath; Z m9 e|J  
sFileName = sName; :LBG6J  
this.nSplitter = nSpiltter; lS]<~  
$3S6{"  
fI>>w)5  
} ?#!Hm`\.  
kKVd4B[#*  
%[\: 8  
public String getSSiteURL() n"vl%!B  
{ a]'sby  
return sSiteURL; wNL!T6"G  
} z!;n\CV@  
8*kZ.-T B  
)QE7$|s  
public void setSSiteURL(String value) *cx mQ  
{ 9+"D8J7  
sSiteURL = value; Q W#]i  
} r`XIn#o  
\s?OvqI:  
s^ rO I~  
public String getSFilePath() y ,isK  
{ `l@[8H%aw  
return sFilePath; @%&;V(  
} $ r|R`n=  
Yh_H $uW  
fiz2544  
public void setSFilePath(String value) PxzeN6f  
{ (RG\U[  
sFilePath = value; 95B w;U3E  
} 1}#v<b$  
@?iLz7SPk  
P7QOlTQI  
public String getSFileName() n={} ='  
{ \kcJF'JFA0  
return sFileName; z_R^n#A~r  
} JL $6Fw;  
fpf1^ TZ  
ozH7c_ <  
public void setSFileName(String value) W)JUMW2|  
{ 4O_z|K_k|  
sFileName = value; r|4jR6%<'m  
} BM=`zGh"  
`?LQd2p  
ta"/R@ k*  
public int getNSplitter() ;tTM3W-h  
{ 'c5#M,G~  
return nSplitter; \eF5* {9  
} 4"1OtBU3  
6l&m+!i  
& i"33.#]  
public void setNSplitter(int nCount) jm&?;~>O  
{ 16/+ O$#y  
nSplitter = nCount; <_@ K4zV  
} 6} "?eW  
} 2A|^6#XN'  
*6 -;iT8  
6la# 0U23  
/* ?xh_qy;  
**Utility.java ,6Sa  
*/ J XKps#,(#  
package NetFox; _?>!Bz m  
4NN-'Z>a  
3 lH#+@  
public class Utility { 7 vUfA"  
c_clpMx=  
,OWdp<z  
public Utility() w,TyV%b[_  
{ !+Z"7e nj  
A Ntp7ad  
sj a;NL  
} J7$1+|"  
N[X%tf\L]F  
//线程睡眠 rg+28tlDn  
public static void sleep(int nSecond) nR4L4tdS  
{ GjZ@f nF  
try{ VaC#9Tp2X  
Thread.sleep(nSecond); 1Lz`.%k`:  
} o/buU{)y  
catch(Exception e) 0CS^S1/[B`  
{ nV38Mj2U  
e.printStackTrace (); x&sT )=#  
} :p@H  
} MbLG8T:y  
u_.V]Rjc  
//日志  84L!r  
public static void log(String sMsg) r5Ej  
{ zk5sAHQ  
System.err.println(sMsg); +*,rOK`C  
} zf $&+E-  
Hb 'fEo r  
Pc{D,/EpR  
public static void log(int sMsg) lMAmico  
{ !jY/}M~F1  
System.err.println(sMsg); heoOOP(#  
} SFoF]U09  
} vM~/|)^0sW  
i0/gyK  
RtH[OZu(8  
/* %(;jx  
**TestMethod.java C&D]!Zv F  
*/ W~p^AHco`  
package NetFox; Tj*o[2mD  
-cyJj LL*  
=YF\mhMQ:  
public class TestMethod { 5FqUFzVqsl  
n>>hfxv(O!  
Hf+A52lrf  
public TestMethod() /:"%m:-P  
{ ///xx/weblogic60b2_win.exe Djx9TBZ5  
try{ Lv,~Mf1|  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); gJi11^PK  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Wd$N[|  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Rg)\o(J  
fileFetch.start(); 9 U1)sPH;  
} 9bgKu6-X  
catch(Exception e){e.printStackTrace ();} M_MiY|%V/K  
$>'}6?C.  
.6!]RA5!=  
}  Cih}  
Oz^+;P1  
]@l~z0^|[_  
public static void main(String[] args) &k\7fvF  
{ 6_;3   
new TestMethod(); ERL(>)  
} ;G!X?(%+  
} @SPmb o  
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