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http断点续传简单实现(java)

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/* Q \S Sv;3_  
**SiteFileFetch.java 5|`./+Ghk  
*/ .]a`-Ofn  
package NetFox; 2|(lKFkQ  
import java.io.*; "\]]?&  
import java.net.*; eht>4)  
[\%a7ji#  
snNB;hkj  
public class SiteFileFetch extends Thread { ;TK$?hrv*1  
jK%Lewq  
J l{My^I5  
SiteInfoBean siteInfoBean = null; //文件信息Bean e2>AL  
long[] nStartPos; //开始位置 hSN38wy  
long[] nEndPos; //结束位置 ><. *5q  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 )nq(XM7  
long nFileLength; //文件长度 :22wq{  
boolean bFirst = true; //是否第一次取文件 U7e2NES  
boolean bStop = false; //停止标志 'Q=(1a11  
File tmpFile; //文件下载的临时信息 b/\l\\$-  
DataOutputStream output; //输出到文件的输出流 U'~]^F%eyu  
m( %PZ*s  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) q0['!G%["  
public SiteFileFetch(SiteInfoBean bean) throws IOException PsS.lhj0"  
{ b2j ~"9  
siteInfoBean = bean; (^_I Ny*  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 2T@?&N^OD  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); : w>R|]  
if(tmpFile.exists ()) R((KAl]dL  
{ i=hA. y`  
bFirst = false; -6X+:r`>u  
read_nPos(); zz<o4b R  
} et(AO)uv6  
else "ub0}p4V  
{ MUCes3YJH  
nStartPos = new long[bean.getNSplitter()]; (\wV)c9  
nEndPos = new long[bean.getNSplitter()]; [M:<!QXw  
} >svx 8CT  
1zCgPiAem  
!9.\A:G  
"5Z5x%3I  
} vIZFI  
W@%g_V}C*  
o3NB3@uj<  
public void run()  `=B v+  
{ u@`y/,PX  
//获得文件长度 IJ:JH=8  
//分割文件 V@EyU/VJ  
//实例FileSplitterFetch -zzT:C  
//启动FileSplitterFetch线程 2E!Q5 l!j  
//等待子线程返回 *Uf>Xr&  
try{ LY#V)f  
if(bFirst) _?K,Jc8j.  
{ H:WuMwD4  
nFileLength = getFileSize(); {h.j6  
if(nFileLength == -1) dYlVJ_0Zr  
{ <^942y-=  
System.err.println("File Length is not known!"); 9T1 - {s R  
} 3;!!`R>e  
else if(nFileLength == -2) #/_ VY.  
{ pwB>$7(_h  
System.err.println("File is not access!"); F[)tg#}@G  
} g&8-X?^Q  
else 6?JvvS5  
{ q]s_hWWv  
for(int i=0;i<nStartPos.length;i++) 0xaK"\Q   
{ [l7n "gJ~  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); `_]UlI_h  
} jz>b>;  
for(int i=0;i<nEndPos.length-1;i++) vfc,{F=Q  
{ +=nWB=iCb  
nEndPos = nStartPos[i+1]; ` 7?EE1o  
} S/l6c P  
nEndPos[nEndPos.length-1] = nFileLength; #>sI XY  
} g; 7u-nP  
} tDMNpl  
5dbj{r)s6i  
ov >5+"q)  
//启动子线程 K(P.i^k  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; w02C1oGfx  
for(int i=0;i<nStartPos.length;i++) 5v=e(Ph +  
{ @Q&k6.{4Z  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), H7meI9L  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), g+(Y)9h&  
nStartPos,nEndPos,i); &^Gp  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); C<w&mFozL  
fileSplitterFetch.start(); cJM.Q_I}Y  
} mHH>qW{`  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), .*J /F$  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); PR,8c  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", a(G}<  
nEndPos = " + nFileLength); `lt[Q>Z  
// fileSplitterFetch[nPos.length-1].start(); : JSuC  
4[Wwm  
,pVe@d'  
//等待子线程结束 $H&:R&Us  
//int count = 0; Pa$"c?QUy  
//是否结束while循环 ::-*~CH)  
boolean breakWhile = false; g yT0h?xDt  
;Sp/N4+  
Z.s0ddM s  
while(!bStop) (CJx Y(1K  
{ +%K~HYN  
write_nPos(); o*oFCR]j  
Utility.sleep(500); rfr]bq5  
breakWhile = true; 9w=[}<E  
_g'x=VJF  
A\13*4:;l  
for(int i=0;i<nStartPos.length;i++) ,3!4 D^  
{ o,@ (]e~  
if(!fileSplitterFetch.bDownOver) yW"[}L h4  
{ |.- Muv  
breakWhile = false; %7?Z|'\  
break; 8`90a\t'Z  
} D#^euNiWd  
} u*rHKZ9i  
if(breakWhile) BKgCuz:y  
break; D6C h6i5$  
BPVOBL@   
.nEiYS|T  
//count++;  k)W&ZY  
//if(count>4) [X>f;;h  
// siteStop(); POX{;[SV  
} xLgZtLt9  
\5Y<UJ Ki  
da@W6Ovx  
System.err.println("文件下载结束!"); }02(Y!Gh  
} P?zaut  
catch(Exception e){e.printStackTrace ();} agQD d8oX  
} %36@1l-N  
#qxo1uV(c  
ud"Kko Rt  
//获得文件长度 =1<v1s|)q  
public long getFileSize() wxT( ktE  
{ ;82?ACCP  
int nFileLength = -1; wzBI<0]z  
try{ QGE0pWL-a  
URL url = new URL(siteInfoBean.getSSiteURL()); 8# x7q>?  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); \0&F'V  
httpConnection.setRequestProperty("User-Agent","NetFox"); Sl@Ucc31  
O=^/58(m  
)lq+Gv[%F  
int responseCode=httpConnection.getResponseCode(); q1m{G1W n  
if(responseCode>=400) "b%FkD  
{ kv;P2:"|  
processErrorCode(responseCode); 77ztDQDtM  
return -2; //-2 represent access is error R dNL f  
} |IS$Om  
(%"9LYv  
IFhS(3 YK[  
String sHeader;  M+:9U&>  
)ybF@emc  
2. v<pqn  
for(int i=1;;i++) > `0mn|+  
{ ?/my G{E  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 8pZOgh  
//Utility.log(in.readLine()); ;|:R*(2   
sHeader=httpConnection.getHeaderFieldKey(i); *%E\mu,,c  
if(sHeader!=null) c]/S<w<  
{ s'$2 }K  
if(sHeader.equals("Content-Length")) R'" c  
{ (L(n%  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 'g3T'2"`5  
break; +(^H L3  
} 8IE^u<H(:  
} %Y>E  
else &So1;RR,_M  
break; j0s$}FPUI  
} o^m?w0 \  
} 3xiDt?&H  
catch(IOException e){e.printStackTrace ();} g(,^'; j  
catch(Exception e){e.printStackTrace ();} T k@~w  
4S[UJ%  
d`~~Ww1  
Utility.log(nFileLength); 5}c8v2R:B  
FZLx.3k4  
c] t@3m  
return nFileLength; h_SkX@"/-  
}  Lw%_xRn)  
[^^Pl:+  
$48 Z>ij?f  
//保存下载信息(文件指针位置) D3%2O`9  
private void write_nPos() q'TIN{\.{  
{ &HtTh {  
try{ BRM!g9  
output = new DataOutputStream(new FileOutputStream(tmpFile)); W|y;Kxy  
output.writeInt(nStartPos.length); D2=zrU3Y64  
for(int i=0;i<nStartPos.length;i++) b};o:  
{ +T8MQ[(4  
// output.writeLong(nPos); EdkIT|c{  
output.writeLong(fileSplitterFetch.nStartPos); 8@RtL,[d  
output.writeLong(fileSplitterFetch.nEndPos); (.VS&Kv#U  
} ou- uZ"$,c  
output.close(); SvrUXf  
} e `OQ6|.k8  
catch(IOException e){e.printStackTrace ();} }W&9}9p"  
catch(Exception e){e.printStackTrace ();} {8oGWQgrj  
} +C[g>c}d  
1ANb=X|hig  
w~ON861  
//读取保存的下载信息(文件指针位置) $2RSYI`py  
private void read_nPos() lW|v_oP9  
{ SD<a#S\o  
try{ ,>8w|951'  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ]vP}K   
int nCount = input.readInt(); ~"NuYM#@  
nStartPos = new long[nCount]; To5hVL<Ex"  
nEndPos = new long[nCount]; Z*Gf`d:  
for(int i=0;i<nStartPos.length;i++) z?( b|v  
{ | L1+7  
nStartPos = input.readLong(); 5t"FNL <(M  
nEndPos = input.readLong(); PB?2{Cj  
} c&FOt  
input.close(); C+[)^ 2M{  
} aB?usVoS  
catch(IOException e){e.printStackTrace ();} -;J6S  
catch(Exception e){e.printStackTrace ();} #sDb611}#  
} #V%98|"  
v(!:HK0oeT  
YRFz ]  
private void processErrorCode(int nErrorCode) B?- poB&  
{ - l^3>!MAM  
System.err.println("Error Code : " + nErrorCode); )%3T1 D/  
} R&a$w8  
{]Hv*{ ]  
9dBxCdpu  
//停止文件下载 ,&qC R sw  
public void siteStop() t(9q 6x3|e  
{ }m~MN4 l  
bStop = true; x!\q69ndv  
for(int i=0;i<nStartPos.length;i++) Q2uV/M1?  
fileSplitterFetch.splitterStop(); 5j6`W?|q  
e}S+1G6r)  
f'H|K+bO  
} ^gZ,A]  
} d7 H*F  
//负责部分文件的抓取 TlRc8r|  
**FileSplitterFetch.java ^|]Dg &N.  
*/ rp{|{>'`.q  
package NetFox; x3Y)l1gh  
g\ vT7x  
tiHR&v  
import java.io.*; q$mc{F($D  
import java.net.*; upL3M`  
I "~.p='  
Z0m`%(MJa  
public class FileSplitterFetch extends Thread { sA77*T  
v{fcQb  
ii-AE L  
String sURL; //File URL y& 1@d+Lf  
long nStartPos; //File Snippet Start Position ?1a9k@[t  
long nEndPos; //File Snippet End Position ne/JC(  
int nThreadID; //Thread's ID Jk6}hUH,  
boolean bDownOver = false; //Downing is over \m G Y'0  
boolean bStop = false; //Stop identical T9H*]LxK  
FileAccessI fileAccessI = null; //File Access interface L/V^#$  
qS FtQ4  
jWv'`c  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Np/\ }J&IF  
{ oSC'b%  
this.sURL = sURL; -4& i t:  
this.nStartPos = nStart; =@?[.`  
this.nEndPos = nEnd; %&| uT  
nThreadID = id; %kjG[C  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 !W9:)5^X  
} `+"(GaZ  
+ovK~K $A  
*^~ =/:  
public void run() (Y@T5-!D  
{ $?G@ijk,  
while(nStartPos < nEndPos && !bStop) ElV!C}g  
{ 5;UIz@BJ  
"8{A4N1B5  
}: HG)V  
try{ .'gm2  
URL url = new URL(sURL); '=n?^EPE3  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 4^F%bXJ)  
httpConnection.setRequestProperty("User-Agent","NetFox"); Oo}h:3?  
String sProperty = "bytes="+nStartPos+"-"; pB 8D  
httpConnection.setRequestProperty("RANGE",sProperty); /uj^w&l#  
Utility.log(sProperty); *}d N.IL,  
J-5>+E,nZ  
8Auek#[  
InputStream input = httpConnection.getInputStream(); ,0.kg  
//logResponseHead(httpConnection); yJq<&g  
y]m: {  
@wI>0B  
byte[] b = new byte[1024]; ExS5RV@v'  
int nRead; JfIXv  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) MK=oGzK  
{ 0lg$zi x(  
nStartPos += fileAccessI.write(b,0,nRead); Y \-W`  
//if(nThreadID == 1) C,Nf|L((6  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 1 _?8OU  
} Pc`d]*BYi  
|'nQvn:{  
< $0is:]  
Utility.log("Thread " + nThreadID + " is over!"); 4a+gM._+O  
bDownOver = true; 'bi;Y1:  
//nPos = fileAccessI.write (b,0,nRead); dm4Q'u  
} ?K>)bA&l'  
catch(Exception e){e.printStackTrace ();} 2@<_,'  
} J* *(7d  
} ~v.mbh  
vSH,fS-n  
:ZV |8xI  
//打印回应的头信息 <\~v$=G  
public void logResponseHead(HttpURLConnection con) _SAM8!q4,  
{ ,X4+i8Yc  
for(int i=1;;i++) &*=!B9OBI  
{ U]=yCEb8p  
String header=con.getHeaderFieldKey(i); oAQQ OtpZN  
if(header!=null) hul,Yd) Z  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); AafS6]y  
Utility.log(header+" : "+con.getHeaderField(header)); S\g9 @g.  
else ayy\7b  
break; 4,I,f>V  
} H9/!oI1P?  
} )S g6B;CJ  
D_DwP$wSo  
k&ci5MpN  
public void splitterStop() &zdS9e-fF  
{ u}[ a  
bStop = true; q!y.cyL  
} aDF@A S  
@:C)^f"  
:> 0ywg  
} Lq2Q:w'  
'[ t.  
,a?)O6?/  
/* gjDNl/r/  
**FileAccess.java MA`nFkVK  
*//文件访问(定位,写) eiKY az  
package NetFox; 'Qy6m'esW  
import java.io.*; j=l2\W#}  
|nefg0`rk  
MJXnAIG?2  
public class FileAccessI implements Serializable{ 6]brL.eGj  
MXaF q K<Y  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 fEHFlgN3Ap  
RandomAccessFile oSavedFile; &B{zS K$N  
long nPos; SGWb*grt  
]<;7ZNG"Y5  
_z@/~M(  
public FileAccessI() throws IOException NfV|c~?d  
{ MzIDeZ  
this("",0); EN!C5/M{&  
} g,Ob/g8uc  
.q9Sg8G  
3Z XAAV  
public FileAccessI(String sName,long nPos) throws IOException LZV-E=`  
{ pU7;!u:c4%  
oSavedFile = new RandomAccessFile(sName,"rw"); lL)f-8DX  
this.nPos = nPos; \sNgs#{7E7  
oSavedFile.seek(nPos); /ox7$|Jyr  
} Hd~g\  
/mkT7,]  
a{kJ`fK   
public synchronized int write(byte[] b,int nStart,int nLen) wpK1nA+7N  
{ {A0jkU  
int n = -1; J!uG/ Us  
try{ "ko*-FrQ  
oSavedFile.write(b,nStart,nLen); [bhKL5l  
n = nLen; @+b$43 ^  
} f24W*#IX  
catch(IOException e) q/EX`%U  
{ *9\j1Nd  
e.printStackTrace (); ?b]zsku8  
} xMjhC;i{  
<_Yd N)x  
u7< +)6-  
return n; D$}hoM1  
} gi!_Nz  
m _)-  
wN[lC|1c  
} QX=TuyO  
dn 6]qW5  
g *Js4  
/* Cbff:IP  
**SiteInfoBean.java "\o#YC  
*/ w6vbYPCN  
package NetFox; KuJ)alD;1  
}4C_r'd6  
1-y8Hy_a2  
public class SiteInfoBean { 6>]_H(z7  
<2pp6je\0s  
rfwJLl/  
private String sSiteURL; //Site's URL a|t~&\@  
private String sFilePath; //Saved File's Path  /a1uG]Mt  
private String sFileName; //Saved File's Name w%])  
private int nSplitter; //Count of Splited Downloading File (<Cq_K w  
t\Vng0  
%~Yo{4mHs  
public SiteInfoBean() ;Nn(  
{//nSplitter的缺省值为5 v9f+ {Y%-  
//default value of nSplitter is 5 jEBn"]\D  
this("","","",5); oMbd1uus  
} :s *  
#/YS  
kLgkUck8]  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) #*iUZo  
{ ~0PzRS^o  
sSiteURL= sURL; >$m<R &  
sFilePath = sPath; ;%n'k  
sFileName = sName; u "0{) ,  
this.nSplitter = nSpiltter; /|v4]t-  
-}6ew@GE  
'yiv.<4  
} EE"8s7ZF  
9lq5\ tL-  
h .Qk{v  
public String getSSiteURL() 7!J-/#!  
{ Jqxd92 bI  
return sSiteURL; "1a;);S=*)  
} |ke0G  
gv67+Mf  
`3\aX|4@  
public void setSSiteURL(String value) 2K:A4)jZ  
{ AS;Sz/YP  
sSiteURL = value; N@|<3R!N*e  
} [<XYU,{R  
6{)pF  
'l'3&.{Yfk  
public String getSFilePath() :ts3_-cr  
{ O\<zQ2m  
return sFilePath; )BJkHED{  
} %"{P?V<-V  
mqZK1<r  
hV@ N -u^  
public void setSFilePath(String value) ZUI6VM  
{ ZxtO.U2  
sFilePath = value; 9^/Y7Wp/@  
} 0Md>-H;ZY  
,V1"Typ#<  
_<Ak M"  
public String getSFileName() b+~_/;Y9  
{ 6Q:Wo)^!  
return sFileName; q(n"r0)=  
} `NtW+v  
kP`#zwp'Ci  
Zu"qTJE/1  
public void setSFileName(String value) uw3vYYFX  
{ .))g]CH  
sFileName = value; znrO~OK  
} {F<0e^*  
2Hd\>{*  
/l<(i+0  
public int getNSplitter() sywuS  
{ y`oj\  
return nSplitter; (utP@d^  
} z|Y54o3  
1{N+B#*<[X  
.2%t3ul[  
public void setNSplitter(int nCount) =AO (  
{ ]njNSn  
nSplitter = nCount; mh8fJ6j29N  
} u[**,.Ecg  
} D?dBm  
!H\;X`W|~D  
1 iox0  
/* 3@" :&  
**Utility.java M-t 9M~  
*/ ,P9F*;Dj  
package NetFox; lrJV"H  
Pm%xX~H  
fnq 3ic"V  
public class Utility { ZiZ@3O6  
3t<a3"{9  
]$ d ;P  
public Utility() ~HIj+kN  
{ 1Le8W)J  
gnH {_  
VzXVy)d  
} 4FzTf7h^  
Ue \A ,  
//线程睡眠 JtO}i{A  
public static void sleep(int nSecond) },d^y:m  
{ K~d'*J-  
try{ ymm]+v5S.]  
Thread.sleep(nSecond); dU9;sx  
} _&]7  
catch(Exception e) 6 rnFXZ\  
{ Md4Q.8  
e.printStackTrace (); GTLS0l)  
} '1D $ ;  
} 1 3 ]e< '  
*IOrv)  
//日志 X| \`\[  
public static void log(String sMsg) :;_}Gxx  
{ B& @ pZYl  
System.err.println(sMsg); )n)AmNpq   
} X{x(p  
;h1hz^Wq  
Tz)Ku  
public static void log(int sMsg) |m KohV qr  
{ :,l16{^  
System.err.println(sMsg); VEy]vr}  
} =6U5^+|d  
} x1Gx9z9  
2OUx@Vj  
dm}1"BU<  
/* lW5Lwyt8  
**TestMethod.java {> ,M  
*/ )jXKPLj  
package NetFox; :h(RS ;  
D9TjjA|zS  
Ja~8ZrcY  
public class TestMethod { ; =n}61  
ho$}#o  
HWV A5E[`Y  
public TestMethod() 'o)Y!VYnJF  
{ ///xx/weblogic60b2_win.exe 1?BLL;[a8  
try{ c1E{J <pZ  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Yeg<MrS4D  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ?;oJ=.T  
SiteFileFetch fileFetch = new SiteFileFetch(bean); `xx.,;S  
fileFetch.start(); pnuo;rs  
} ~qZ6I)?  
catch(Exception e){e.printStackTrace ();} $e+4Kt ,  
:4AIYk=q  
CmXLD} L_x  
} VWzQXo  
^.:&ZsqV  
>>$L vQ  
public static void main(String[] args) &jY| :Fe  
{ PESvx>:  
new TestMethod(); Je|:\Qk  
} ?GH/W#{o)  
} x%s1)\^A  
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