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http断点续传简单实现(java)

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/* Ev,b5KelD  
**SiteFileFetch.java ShJBOaE; -  
*/ no7Q%O9  
package NetFox; A<[BR*n  
import java.io.*; 5XinZ~  
import java.net.*; o| 9Mj71  
sYd)r%%AU  
d1u6*&@lf  
public class SiteFileFetch extends Thread { c<5(c%a  
r^;1Sm  
~D_Wqr  
SiteInfoBean siteInfoBean = null; //文件信息Bean u9G  
long[] nStartPos; //开始位置 (XQ:f|(  
long[] nEndPos; //结束位置 {3K`yDF  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 :-e[$6}S  
long nFileLength; //文件长度 %B04|Q  
boolean bFirst = true; //是否第一次取文件 &'W ~~ir  
boolean bStop = false; //停止标志 oZw#]Q@  
File tmpFile; //文件下载的临时信息 8GT4U5c ;  
DataOutputStream output; //输出到文件的输出流 PPj%.i)  
Y9y'`}+  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) 6yedl0@wa!  
public SiteFileFetch(SiteInfoBean bean) throws IOException h&<>nK   
{ SH;:bLk_  
siteInfoBean = bean; EsjZ;D, c(  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); #~`d ;MC  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); TH? wXd\  
if(tmpFile.exists ()) C*Wyw]:r  
{ Wrs6t  
bFirst = false; ;I]$N]8YI  
read_nPos(); H1hADn  
} Z1R{'@Y0Z  
else =90)=Pxd  
{ M Jtn)gXb  
nStartPos = new long[bean.getNSplitter()]; l vfplA  
nEndPos = new long[bean.getNSplitter()]; f<*-;  
} @hOT< Uo  
mxmj  
*&$2us0%%  
b2UqN]{  
} Lo5CVlK  
+lw*/\7  
ETrL3W<  
public void run() R)'[Tt`#R  
{ ]TSzT"_r~~  
//获得文件长度 DcmRvi)&6  
//分割文件 )X 'ln  
//实例FileSplitterFetch K# BZ Jcb  
//启动FileSplitterFetch线程 QR h %S{  
//等待子线程返回 mLH,6rO9  
try{ x1`zD*{  
if(bFirst) =|_k a8{?  
{ M6"a w6  
nFileLength = getFileSize(); O*m9qF<  
if(nFileLength == -1) dS;Ui]/J  
{ i} ?\K>BWq  
System.err.println("File Length is not known!"); lcEUK  
} 7 MG<!U  
else if(nFileLength == -2) @%rj1Gn  
{ +=#@1k~  
System.err.println("File is not access!"); .*nr3dY  
} {lNG:o  
else /H :Bu  
{ Ed>n/)Sm  
for(int i=0;i<nStartPos.length;i++) |!uC [=  
{ Hzojv<c  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); IS%e5  
} A\QrawBp0l  
for(int i=0;i<nEndPos.length-1;i++) =$WDB=i  
{ ?xb2jZ/0X  
nEndPos = nStartPos[i+1]; tW"s^r=95  
} lfyij[6q+  
nEndPos[nEndPos.length-1] = nFileLength; x(y=.4Yf+  
} xH{V.n&v  
} 7!^Zsp^+  
u^+ (5|  
]RTK:%  
//启动子线程 T,5(JP(h3  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; *DPKV$  
for(int i=0;i<nStartPos.length;i++) /|,:'W%U  
{ LqoH]AcN  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), nVGWJ3  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), sm at6p[  
nStartPos,nEndPos,i); A5%cgr% 6  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); xZ>@wBQ  
fileSplitterFetch.start(); `a]feAl  
} CAbT9W z&  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Pt?d+aBtV  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); $QJ,V~  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 4\(|V fy  
nEndPos = " + nFileLength); ,Zb_Pu   
// fileSplitterFetch[nPos.length-1].start(); .5+5ca  
#E@X'jwu  
vz`r !xj)  
//等待子线程结束 s^ K:cz  
//int count = 0; J9XV:)Yv#  
//是否结束while循环 mZ4I}_\,  
boolean breakWhile = false; yvV]|B@sO  
?D=t:=  
rl XMrn  
while(!bStop) 2[5z6oG  
{ trM)&aQto  
write_nPos(); ./Wi(p{F  
Utility.sleep(500); <*5`TE0J  
breakWhile = true; Rmh u"N/q  
<k 7q 9"\4  
LGPg\g`  
for(int i=0;i<nStartPos.length;i++) HOlMj!.  
{ 4nGr?%>  
if(!fileSplitterFetch.bDownOver) zH1ChgF=}  
{ sH\ h{^  
breakWhile = false; d6{0[T^L  
break; y\}<N6  
} l#;o^H i  
} @rxfOc0J#  
if(breakWhile) r9$7P?zm  
break; 1zc-$B`t  
DWcEl:  
l8By2{pN  
//count++; - xQJY)  
//if(count>4) 9H,Ec,.  
// siteStop(); uU#e54^  
} 0xpE+GY  
e(Ub7L#  
lZ5TDS  
System.err.println("文件下载结束!"); y<n<uZ;  
} ej{7)#  
catch(Exception e){e.printStackTrace ();} Nj;G%KAP  
} gclw>((5  
q%c"`u/v/  
X1\ao[t<;c  
//获得文件长度 GM>Ms!Y  
public long getFileSize() cK6IyJx-  
{ 1iIag}?p  
int nFileLength = -1; mY/x|)MmM  
try{ #GA6vJ4^s  
URL url = new URL(siteInfoBean.getSSiteURL()); H"%SzU  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ~6Df~uN  
httpConnection.setRequestProperty("User-Agent","NetFox"); =.f<"P51k  
cK H By  
6 +x>g  
int responseCode=httpConnection.getResponseCode(); =-8y =  
if(responseCode>=400) ) GF>]|CG  
{ {^SHIL  
processErrorCode(responseCode); YOY{f:ew  
return -2; //-2 represent access is error n<66 7 <  
} ,: 4+hJ<q  
4@*`V  
MU5#ph  
String sHeader; R9O[`~BA2  
-'Y@yIb  
e*jfxQ=qG  
for(int i=1;;i++) /_CSRi&  
{ L$s ;tJ   
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); h|Udw3N1L  
//Utility.log(in.readLine()); i`HXBq!|w  
sHeader=httpConnection.getHeaderFieldKey(i); .GNl31f0  
if(sHeader!=null) pPt w(5bH  
{ ~h6aTN  
if(sHeader.equals("Content-Length")) $sBje*;  
{ TH#5j.uUs  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); %<Kw  
break; N.qS;%*o{e  
} y/yg-\/XF  
} e6igx  
else "ba>.h,#'  
break; y|[YEY U)  
} L'$;;eM4  
} rH5'+x K  
catch(IOException e){e.printStackTrace ();} [wR x)F"  
catch(Exception e){e.printStackTrace ();} X1; ljX  
BSbi.@@tp  
T1c.ER}17  
Utility.log(nFileLength); C4/p5J  
34Z$a{ w  
8f{;oO  
return nFileLength; \' ;zD-MX  
} l/o 4bkV  
gCc::[}\Y  
ejI nJ  
//保存下载信息(文件指针位置) O^yD b  
private void write_nPos() @$%[D`Wa<  
{ Zi~-m]9U  
try{ o"./  
output = new DataOutputStream(new FileOutputStream(tmpFile)); n8vteGQ  
output.writeInt(nStartPos.length); p:q?8+W-r  
for(int i=0;i<nStartPos.length;i++) $Hbd:1%i {  
{ VA0p1AD  
// output.writeLong(nPos); @8xa"Dc  
output.writeLong(fileSplitterFetch.nStartPos); XZ!^kftyW  
output.writeLong(fileSplitterFetch.nEndPos); ,zU7UL^I  
} u+/1ryp  
output.close(); sFWH*k dP?  
} CPS1b  
catch(IOException e){e.printStackTrace ();} t+`>zux5(T  
catch(Exception e){e.printStackTrace ();} NgPY/R>  
} 1>e%(k2w%  
(&t8.7O  
]@bu%_s"  
//读取保存的下载信息(文件指针位置) @-F[3`HeA  
private void read_nPos() lL{1wCsl  
{ 5fVm392+  
try{ #K _E/~  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); q%xq\L.  
int nCount = input.readInt(); _|%l) KO  
nStartPos = new long[nCount]; " .:b43Z  
nEndPos = new long[nCount]; %V3xO%  
for(int i=0;i<nStartPos.length;i++) *{e?%!Q  
{ C.}Vm};M  
nStartPos = input.readLong(); }|!9aojr  
nEndPos = input.readLong(); /~B \1  
} = 7TK&  
input.close(); e[AwR?=  
} xfJ&11fG2  
catch(IOException e){e.printStackTrace ();} Z>+Tzvfud  
catch(Exception e){e.printStackTrace ();} ra*(.<&  
} TScI_8c>  
C=|X]"*:u0  
/WX 0}mWu  
private void processErrorCode(int nErrorCode) D%NVqk|  
{ Ko|p&-Z;  
System.err.println("Error Code : " + nErrorCode);  #3m7`}c  
} 't:s6  
#>/s tU-  
m^rrbU+HM?  
//停止文件下载 k%S;N{Qh@  
public void siteStop() K4>nBvZ?v  
{ mfpL?N  
bStop = true; _wMYA8n  
for(int i=0;i<nStartPos.length;i++) KJ&~z? X  
fileSplitterFetch.splitterStop(); rAZsVnk?  
:VEy\ R>W  
]&l%L4Z  
} DeTD.)pS  
} &z"sT*3  
//负责部分文件的抓取 |w7D&p$  
**FileSplitterFetch.java ~'aK[3  
*/ ek3,ss3  
package NetFox; ^w*$qzESy  
s.oh6wz  
'5BM*4,:O  
import java.io.*; Oe^oigcM  
import java.net.*; vx&jI$t8  
A(#4$}!n5  
tf+5@Zf]4  
public class FileSplitterFetch extends Thread { +W-,74A  
jJfV_#'N'  
hi(u L>\  
String sURL; //File URL V\(p6:1(6K  
long nStartPos; //File Snippet Start Position Wk"\aoX"E  
long nEndPos; //File Snippet End Position [C TR8  
int nThreadID; //Thread's ID OY>0qj  
boolean bDownOver = false; //Downing is over KKLW-V\6K  
boolean bStop = false; //Stop identical Rw9 *!<Izt  
FileAccessI fileAccessI = null; //File Access interface `LID*uD;_  
R?K[O   
LG qg0 (  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Hlg Q0qb  
{ wK[Xm'QTPJ  
this.sURL = sURL; xf?6_=  
this.nStartPos = nStart; t:h~p-&QB  
this.nEndPos = nEnd; qr~= S  
nThreadID = id; }1/`<m  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ;:)?@IuSy  
} &InMI#0mV  
9 yE   
e%O]U:Z  
public void run() j;+!BKWy4  
{ EN!Q]O|  
while(nStartPos < nEndPos && !bStop) :',Q6j(s  
{ ~dO&e=6Hk  
z2GT9  
Xw2tCRzD  
try{ ,n &e,I  
URL url = new URL(sURL); B- VhUS  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); qAF.i^  
httpConnection.setRequestProperty("User-Agent","NetFox"); 9J!@,Zsh  
String sProperty = "bytes="+nStartPos+"-"; GG@&jcp7  
httpConnection.setRequestProperty("RANGE",sProperty); *7yu&a8  
Utility.log(sProperty); JZS#Q\JN  
N))G/m3  
;| :^zo  
InputStream input = httpConnection.getInputStream(); z&@Vg`w"  
//logResponseHead(httpConnection); w u  
/`j~r;S  
WF.y"{6>  
byte[] b = new byte[1024]; 9se ,c  
int nRead; 6*:mc  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) \?9{H6<=  
{ $M(ZKS3,j  
nStartPos += fileAccessI.write(b,0,nRead); R3dCw:\O+Z  
//if(nThreadID == 1) %HNe"7gk  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 6_w;dnVA  
} FLI0C  
)Z2l*fV  
dgIEc]#pH  
Utility.log("Thread " + nThreadID + " is over!"); ?+WSYg0  
bDownOver = true; BP7&w d  
//nPos = fileAccessI.write (b,0,nRead); ?_+h+{/@B  
} 3]iBX`Ni  
catch(Exception e){e.printStackTrace ();} !PFc)J  
}  #)r  
} {J}Zv5  
}gr6naz  
q-;z!iq|!  
//打印回应的头信息 C6XZZ  
public void logResponseHead(HttpURLConnection con) ;6?VkF  
{ \R0&*cnmo  
for(int i=1;;i++) a_pNFe  
{ 9Xu O\+z  
String header=con.getHeaderFieldKey(i); *{y/wgX  
if(header!=null) >J \}&!8,  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); `XJU$c  
Utility.log(header+" : "+con.getHeaderField(header)); r3hUa4^97  
else i8tH0w/(M  
break; $g?`yE(K  
} 3%JPJuNVw  
} m R3km1T  
7|"gMw/  
Psf'#4g  
public void splitterStop() *)2& gQ&%+  
{ (RL5L=,u  
bStop = true; #SzCd&hI  
} S$Cht6m  
&D|wc4+  
16p$>a<6  
} ^h:%%\2  
v/4Bt2J  
/puM3ZN  
/* 5DHFxym'  
**FileAccess.java Dm"@59x  
*//文件访问(定位,写) P7||d@VW,  
package NetFox; AvN\^ &G  
import java.io.*; FE`:1  
jG0o-x=X  
tWNz:V  
public class FileAccessI implements Serializable{ !]W}I  
5jpb`Axj#  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 *:q,G  
RandomAccessFile oSavedFile; p&:(D=pIu  
long nPos; RSNukg  
Mpm#a0f  
"uz}`G~O  
public FileAccessI() throws IOException s5s'$|h"  
{ Z"# /,?|3@  
this("",0); 6+MZ39xC  
} gZFtV  
H^N@fG<*dh  
Z.Sq5\d  
public FileAccessI(String sName,long nPos) throws IOException IXmtjRv5  
{ H'L ~8>  
oSavedFile = new RandomAccessFile(sName,"rw"); )<D(Mb 2p|  
this.nPos = nPos; r&G=}ZMO  
oSavedFile.seek(nPos); }#[MV+D  
} 7yU<!p?(  
vsjl8L  
RaS7IL:e  
public synchronized int write(byte[] b,int nStart,int nLen) | 'SqG}h  
{ -N')LY  
int n = -1; l>i<J1  
try{ QsaaA MGY  
oSavedFile.write(b,nStart,nLen); *EZ'S+wR  
n = nLen; v.08,P{b  
} Y6|8;2E  
catch(IOException e) p~T)Af<(  
{ D3^Yc:[_@  
e.printStackTrace (); f?iQ0wv)  
} X0=#e54  
;OlC^\e  
!,#42TY*X  
return n; ::\7s  
} (W<n<sl:-  
p+O 2 :  
6wzTX8  
} 2BU%4IG  
!,mv 7Yj  
 1k5o?'3&  
/* u0;FQr2  
**SiteInfoBean.java  xZ*.@Pkr  
*/ 7R 40t3  
package NetFox; tFvc~zz9  
1!@KRV  
Zd/ACZ[  
public class SiteInfoBean { cG|ihG5)  
MYzyg  
.[v4'ww^  
private String sSiteURL; //Site's URL ,8KD-"l^g  
private String sFilePath; //Saved File's Path 0L "+,  
private String sFileName; //Saved File's Name PKoB~wLH  
private int nSplitter; //Count of Splited Downloading File <z3:*=!  
3[RbVT  
1D42+cy  
public SiteInfoBean() }";\8  
{//nSplitter的缺省值为5 y/>]6Pj  
//default value of nSplitter is 5 N798("  
this("","","",5); [@U2a$k+d  
} vHY."$|H  
6.z8!4fpl  
]j.??'+rg  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) \0'7p-T6  
{ zV(F9}^  
sSiteURL= sURL; *&b~cyC  
sFilePath = sPath; aZ%  
sFileName = sName; o2cZ  
this.nSplitter = nSpiltter; o}XbFL n  
`%lgT+~T  
\:cr2w'c  
} ?fB}9(6  
S7cxEOfAu  
P +U=/$o  
public String getSSiteURL() "o +" Jd  
{ #C+""qm  
return sSiteURL; 0hTv0#j#  
} >&K1+FSmyJ  
FFH9 $>A  
2k,!P6fgl  
public void setSSiteURL(String value) Mf0XQ3n`H  
{ )q?z "F|  
sSiteURL = value; c;w%R8z  
} :NL.#!>/  
%m:T?![XO  
T&_!AjH  
public String getSFilePath() C wKo'PAJ  
{ xm@vx}O:  
return sFilePath;  fL9R{=I%  
}  '&/"_  
4%Q8>mEvT  
Sb=cWn P  
public void setSFilePath(String value) Fg8i} >w  
{ Jsee8^_~  
sFilePath = value; |Uz?i7z  
} \Uun2.K  
gkdd#Nrk  
Gld|w=qr  
public String getSFileName() rs$sAa*f  
{ K252l,;|  
return sFileName; $42C4I*E  
} ;eznONNF  
Dp 0   
_w+ix9Fr?  
public void setSFileName(String value) 2.=3:q!H<%  
{ rA9BY :N@  
sFileName = value; (\ `knsE!  
} dQ97O{O:i  
!br0s(|  
?MevPy`H  
public int getNSplitter() &DdFK.lt  
{ ,5jE9  
return nSplitter; "j5b$T0P>  
} _@3?yv~ D  
\>NjeMuWU  
e-;$Iv  
public void setNSplitter(int nCount) 7<V(lX.{  
{ Ic 4>kKh  
nSplitter = nCount; Zfyr& ]"  
} jIx5_lFe  
} cT abZc  
>jjuWO3T  
@DYxxM-  
/* @&;y0N1xo  
**Utility.java k~WX6rEJ  
*/ T)Byws  
package NetFox; [xT2c.2__J  
noiUi>G;:  
6 flc  
public class Utility { {l= !  
a%>p"4WL  
Uv,_VS(  
public Utility() T$/6qZew  
{ ~g$Pb[V  
O@ jW&-;  
JFVal#  
} T69'ta32V  
HVzG }r(J  
//线程睡眠 'ypJGm  
public static void sleep(int nSecond) SS@F:5),  
{ 4CO:*qG)o  
try{ (9x8,f0z  
Thread.sleep(nSecond); )P\Vd #  
} ,mH2S/<}S  
catch(Exception e) ]Lq9Ompf(t  
{ kKnz F  
e.printStackTrace (); YK#bzu ,!  
} }?xu/C  
} (v*$ExF  
9,y*kC  
//日志 #"%=7(  
public static void log(String sMsg) Hk%m`|Z  
{ O.S(H1z<G  
System.err.println(sMsg); `i0RLGze  
} '7}s25[{\  
<\c 5  
Hs<vCL \  
public static void log(int sMsg) SlvQ)jw%  
{ H)1< ;{:  
System.err.println(sMsg); xfw)0S  
} 6bCC6G  
} |S#)[83*3  
O G#By6O  
DzX5_ kA  
/* M H }4F  
**TestMethod.java eS9/- Y  
*/ 'Syq!=,  
package NetFox; rgheq<B:  
weC$\st:D  
SLRQ3<0W_  
public class TestMethod { {zhN>n_  
i[)H!%RV*  
T%K"^4k  
public TestMethod() }ex2tkz  
{ ///xx/weblogic60b2_win.exe tv,iCV  
try{ u(\O  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); a2 fV0d6*l  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); *,!6#Z7  
SiteFileFetch fileFetch = new SiteFileFetch(bean); $d.UF!s  
fileFetch.start(); 2w93 ~j  
} 'Uqz,  
catch(Exception e){e.printStackTrace ();} R+IT)2  
:.Vn  
'~A~gK0  
} n?vrsqmZ  
h_L-M}{OG  
|RX u O  
public static void main(String[] args) K:/%7A_{  
{ eZs34${fN  
new TestMethod(); xS]=WO*  
} ,o\v umx  
} !u@e^J{Ao  
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