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http断点续传简单实现(java)

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/* Nl { 7  
**SiteFileFetch.java oKRFd_r+  
*/ alc]  
package NetFox; DKTD Z*  
import java.io.*; %MbyKz:X  
import java.net.*; L@nebT;\'  
{M [~E|@D  
zFywC-my@  
public class SiteFileFetch extends Thread { , |l@j%  
jQ?LHUE  
#sZIDn J#  
SiteInfoBean siteInfoBean = null; //文件信息Bean 1+a@k  
long[] nStartPos; //开始位置 .1LPlZ  
long[] nEndPos; //结束位置 7-X/>v  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 2 Kl a8  
long nFileLength; //文件长度 Ssf+b!e]  
boolean bFirst = true; //是否第一次取文件 K^aj@2K{  
boolean bStop = false; //停止标志 nS.2C>A  
File tmpFile; //文件下载的临时信息 qi&D+~Gv!  
DataOutputStream output; //输出到文件的输出流 Ib6(Bp9.L  
1M+oTIN  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) N 'i,>  
public SiteFileFetch(SiteInfoBean bean) throws IOException IM=+3W;ak  
{ %l]Rh/VPn?  
siteInfoBean = bean; \DS^i`o)rY  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); MxTmWsaW  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); )&,K94  
if(tmpFile.exists ()) doM?8C#`  
{ \Tyf*:_F>  
bFirst = false; Ig9d#c  
read_nPos(); g_vm&~U/'  
} [x5mPjgw  
else 2d8=h6  
{ w.uK?A>W,  
nStartPos = new long[bean.getNSplitter()]; hg8Be6G <  
nEndPos = new long[bean.getNSplitter()]; DvYwCgLR  
} %'0&ElQ  
4-V)_U#8  
O,|\"b1(  
3cixQzb}u  
} cIb4-TeV  
M|8 3HTJ  
W Y:s gG  
public void run() ('4wXD]C  
{ h55>{)(E  
//获得文件长度 K6B4sE  
//分割文件 8teJ*sz  
//实例FileSplitterFetch .YR8v1Cp  
//启动FileSplitterFetch线程 Za%LAyT_s  
//等待子线程返回 6,+nRiZ  
try{ *ik/p  
if(bFirst) #tDW!Xv?  
{ C ) ?uE'  
nFileLength = getFileSize(); Kt6>L5:94  
if(nFileLength == -1) mxp Y&Y  
{ yFjVKp'P  
System.err.println("File Length is not known!"); |dk[cX>  
} 8W -@N  
else if(nFileLength == -2) 1 i3k  
{ xA #H0?a]  
System.err.println("File is not access!"); k':s =IXW  
} 6t7fa<  
else V!&P(YO:  
{ 6P*O&1hv  
for(int i=0;i<nStartPos.length;i++) J(s;$PG  
{ X;!~<~@Y  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); /oL8;:m  
} _a5(s2wq+  
for(int i=0;i<nEndPos.length-1;i++) OipqoI2  
{ i_ QcC  
nEndPos = nStartPos[i+1]; Q9slfQ  
} m@\ZHbq  
nEndPos[nEndPos.length-1] = nFileLength; .~mCXz<x  
} 8\# ^k#X  
} ]tY:,Mfs  
t&}6;z 3  
Fo}7hab  
//启动子线程 u|fXP)>.  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; PJ q yvbD  
for(int i=0;i<nStartPos.length;i++) 1mH\k5xu  
{ %e_"CS  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), &HDP!SLS  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),  'Cc(3  
nStartPos,nEndPos,i); !w2gGy:I>  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); A-uB\ L  
fileSplitterFetch.start(); F]_cbM{8/  
} *e/K:k  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), `.v(fC  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1);  &`Ck  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ln<]-)&C  
nEndPos = " + nFileLength); 8)wt$b  
// fileSplitterFetch[nPos.length-1].start(); vAi$ [p*im  
o6L9UdT   
!')y&7a~  
//等待子线程结束 y%cO#P@  
//int count = 0; -F1- e+=  
//是否结束while循环 .C bGDZ  
boolean breakWhile = false; 1-VT}J(  
SEd5)0X^  
CxF-Z7 '  
while(!bStop) ~cqryr9  
{ _[K#O,D,  
write_nPos(); z`U Ukl}T  
Utility.sleep(500); c`G&KCw)d  
breakWhile = true; ;3m!:l  
i8PuC^]  
=? :@  
for(int i=0;i<nStartPos.length;i++) A6"Hk0Hf  
{ }Je>;{&%  
if(!fileSplitterFetch.bDownOver) :}q\tNY<  
{ \a|L/9%  
breakWhile = false; pq! %?m]  
break; ,k0r  
} N_DT7  
} )S@jDaU<  
if(breakWhile) L%cVykWY"  
break; vqNsZ 8|`  
5#2 F1NX  
jC, FG'P  
//count++; R;}22s  
//if(count>4) XFqJ 'R  
// siteStop(); =A!S/;z>  
} [aqu }Su  
,/,9j{|"j  
39TT{>?`w  
System.err.println("文件下载结束!"); O'DW5hBL0  
} uCP>y6I  
catch(Exception e){e.printStackTrace ();} rrBAQY|.  
} KMK`F{  
HOi C  
E]} n(  
//获得文件长度 A74920X`W  
public long getFileSize() ,|T7hTn=  
{ -yx/7B5@  
int nFileLength = -1; ktH8as^54!  
try{ g:#d l\k  
URL url = new URL(siteInfoBean.getSSiteURL()); M>H=z#C>/A  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); my.`k'  
httpConnection.setRequestProperty("User-Agent","NetFox"); [_6&N.  
'mMjjG9  
8E^@yZo{  
int responseCode=httpConnection.getResponseCode(); \wav?;z  
if(responseCode>=400) f [o%hCS  
{ x"4%(xBu  
processErrorCode(responseCode); \f Lvw  
return -2; //-2 represent access is error r/:%}(7;  
} +cB&Mi5  
>cR)?P/o  
|M~ON=  
String sHeader; 1s7^uA$}6  
2k -+^}r  
C!x/ ^gw  
for(int i=1;;i++) >'=MH2;  
{ %{5n1w  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 9'~- U  
//Utility.log(in.readLine()); FG-L0X  
sHeader=httpConnection.getHeaderFieldKey(i); ;</Lf=+Vm  
if(sHeader!=null) F?4(5 K  
{ 'cdN3i(  
if(sHeader.equals("Content-Length")) Iw=Sq8  
{ }nx=e#[g%2  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); T1Ta?b  
break; *~VxC{  
} 40P) 4w  
} 4FMF|U  
else 6`H.%zM  
break; ]$iN#d|ZU  
} d^D i*&X  
} (Xx n\*S  
catch(IOException e){e.printStackTrace ();} n&XGBwgW  
catch(Exception e){e.printStackTrace ();} {1lO  
0 t.p1  
-8Ti*:  
Utility.log(nFileLength); m:CTPzAt  
\E4B&!m  
\FzM4-  
return nFileLength; 15H6:_+=0  
} uOi&G:=  
t}p@:'  
NX6nQ  
//保存下载信息(文件指针位置) ' [0AHM  
private void write_nPos() d]v+mVAyE  
{ +V(5w`qx  
try{ I=Zx"'Um  
output = new DataOutputStream(new FileOutputStream(tmpFile)); )9j06(<A  
output.writeInt(nStartPos.length); -pb&-@Hul  
for(int i=0;i<nStartPos.length;i++) %!j:fJ()  
{ [J#1Ff;  
// output.writeLong(nPos); Bx~[F  
output.writeLong(fileSplitterFetch.nStartPos); Ubz"rCjq  
output.writeLong(fileSplitterFetch.nEndPos); Ukphd$3J=  
} Q=cQLf;/'  
output.close(); 'ktHPn ,K  
} C;B}3g&  
catch(IOException e){e.printStackTrace ();} u=l1s1>  
catch(Exception e){e.printStackTrace ();} JiS5um=(.  
} /X8 <C=}  
7,$z;Lr0S  
|QZ 58)>  
//读取保存的下载信息(文件指针位置) ' P"g\;Ij  
private void read_nPos() [IBQvL  
{ aw $L$7b}  
try{ %:C ]7gQ  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); rXi uwz\  
int nCount = input.readInt(); TCVl8)j  
nStartPos = new long[nCount]; '?*g%Yuz  
nEndPos = new long[nCount]; j -O2aL  
for(int i=0;i<nStartPos.length;i++) n-;y*kD  
{ = bt]JRU  
nStartPos = input.readLong(); >`T5]_a  
nEndPos = input.readLong(); ]dPZ.r  
} p='-\M74K  
input.close(); deX5yrvOie  
} hP@(6X,"  
catch(IOException e){e.printStackTrace ();} wo^Sy41bF  
catch(Exception e){e.printStackTrace ();} b3$k9dmxV+  
} T3&`<%,f  
 t,%iL  
SS.jL)  
private void processErrorCode(int nErrorCode) !>^JSHR4t  
{ E_ucab-Fi  
System.err.println("Error Code : " + nErrorCode); f<jb=\}x  
} Q[ieaL6&  
hq>Csj==@  
g=)J~1&p  
//停止文件下载 72db[  
public void siteStop() n]!fO 6kj  
{ rp34?/Nz  
bStop = true; &lc8G  
for(int i=0;i<nStartPos.length;i++) V`hu,Y;%  
fileSplitterFetch.splitterStop(); UH`hOJ?  
xl4=++pu)  
QP I+y8N=  
} ctmQWrk|B  
} u62)QJE  
//负责部分文件的抓取 }odV_WT  
**FileSplitterFetch.java |01?w|  
*/ ,Fqz e/  
package NetFox; pb;")Q'  
{y^3> 7  
=d;Vk  
import java.io.*; 2YwVU.*>  
import java.net.*; y>VcgLIB  
do/)~9[4\  
"E!mva*NU  
public class FileSplitterFetch extends Thread { &x:JD1T}  
ztM<J+  
wzcai 0y*  
String sURL; //File URL USML~]G z  
long nStartPos; //File Snippet Start Position 0(>rG{u  
long nEndPos; //File Snippet End Position ph:3|d  
int nThreadID; //Thread's ID w2gf&Lc\  
boolean bDownOver = false; //Downing is over [pOg'  
boolean bStop = false; //Stop identical 7hNb/O004  
FileAccessI fileAccessI = null; //File Access interface /L=(^k=a.;  
" BTE  
F 8yF  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ]hw-Bu\{  
{ p QE)p  
this.sURL = sURL; YhKZ|@  
this.nStartPos = nStart;  NY  
this.nEndPos = nEnd; MLVB^<qkeH  
nThreadID = id; j#A%q"]8  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 mPZGA\  
} y f1CXldi  
<_S@6 ?  
Xg<[fwW  
public void run() ~.tvrx g  
{ UV7%4xM5v  
while(nStartPos < nEndPos && !bStop) "u^EleE!  
{ #} ,x @]p  
=J'P.  
Qu*1g(el!o  
try{ <EX7WA  
URL url = new URL(sURL); |(IO=V4P  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Rhgj&4  
httpConnection.setRequestProperty("User-Agent","NetFox"); h,t|V}Wb  
String sProperty = "bytes="+nStartPos+"-"; .=R lOK  
httpConnection.setRequestProperty("RANGE",sProperty); ?2J?XS>  
Utility.log(sProperty); x!TZ0fq0  
t={0(  
q%3<Juq~$  
InputStream input = httpConnection.getInputStream(); O mMX$YID  
//logResponseHead(httpConnection); ~9o6 W",  
lPq\=V  
O_,O,1  
byte[] b = new byte[1024]; U..<iNQE5  
int nRead; [IX+M#mf  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) f_mhD dq  
{ .QWhK|(.!  
nStartPos += fileAccessI.write(b,0,nRead); L^Wz vv]  
//if(nThreadID == 1) &V=7D#L  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 6 DF  
} XJ\hd,R   
3fS}:!sQ  
xh9qg0d  
Utility.log("Thread " + nThreadID + " is over!"); %|Qw9sbd  
bDownOver = true; Y>6.t"?Q^  
//nPos = fileAccessI.write (b,0,nRead); B&KL2&Z~Pq  
} {ShgJ ;! Q  
catch(Exception e){e.printStackTrace ();} mB 55PYA  
} Un=a fX?j  
} +Ghi}v  
r#876.JK  
w<wV]F*  
//打印回应的头信息 `^F: -  
public void logResponseHead(HttpURLConnection con) _2Zp1h,  
{ =yi OJyx  
for(int i=1;;i++) 7qIB7_K5  
{ '&yg {n  
String header=con.getHeaderFieldKey(i); Q\_{d0 0  
if(header!=null) @"87F{!  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); *YV S|6bs  
Utility.log(header+" : "+con.getHeaderField(header)); fv'4f$U  
else 85Y|CN] vQ  
break; X)Gp7k1w  
} v|t{1[C  
} ?m%h`<wgMc  
%e%7oqR?  
*> 3Qd7  
public void splitterStop() o+?@5zw -&  
{ htJuGfDx1  
bStop = true; 4jwu'7 Q  
} = 7/-i  
u=K2Q4  
~UMOT!4}3  
} t8J/\f=  
F@W*\3)  
'5.\#=S1  
/* }0/a\  
**FileAccess.java F 1W+o?B  
*//文件访问(定位,写) zmFws-+A  
package NetFox; :[7lTp   
import java.io.*; [~%`N*G  
&w\ I<J`T  
CY"i-e"q<Q  
public class FileAccessI implements Serializable{ %vqT#+x  
pO/%N94s  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 a5c'V   
RandomAccessFile oSavedFile; nfE@R."A  
long nPos; _ n O.-  
Jbw!:x [  
HkjEiU  
public FileAccessI() throws IOException 'p}`i/  
{ dk5|@?pe  
this("",0); G2Qjoe`Uc  
} DZ`k[Z.VZ  
=Viy^ieN$  
F8mC?fbK9  
public FileAccessI(String sName,long nPos) throws IOException Yv\!vW7I  
{ ExhL[1E  
oSavedFile = new RandomAccessFile(sName,"rw"); &a #GXf  
this.nPos = nPos; HYClm|   
oSavedFile.seek(nPos); /=T"=bP#/  
} L]-w;ll-  
;iX<`re~  
YMB~[]$V<  
public synchronized int write(byte[] b,int nStart,int nLen) 3)E(RyQA3  
{ Y`li> .\  
int n = -1; >)Dhi+D  
try{ ,;iA2  
oSavedFile.write(b,nStart,nLen); JeQ[qQ  
n = nLen; s-D?)  
} ([pSVOnIz  
catch(IOException e) oXal  
{ ~<O,Vs_C/  
e.printStackTrace (); \+B?}P8N*l  
} JZx%J)  
[X"k> Sq  
VTw/_Hf2p  
return n; ~ =.CTm]vf  
} $$gtZ{ukQ  
0s%6n5>  
hPO>,j^  
} Q<=Y  
O% $O(l  
Rt4di^v  
/* KTmaglgp  
**SiteInfoBean.java CT"Fk'B'  
*/ k|j:T[_  
package NetFox; OgMI  
+VOb  
w-rOecwFvu  
public class SiteInfoBean { [ b1hC ~I;  
#+G`!<7/@f  
}~zO+Wf2  
private String sSiteURL; //Site's URL Uf2:gLrF  
private String sFilePath; //Saved File's Path c E76L%O  
private String sFileName; //Saved File's Name xqWj|jA  
private int nSplitter; //Count of Splited Downloading File i^/54  
sR79 K1*j  
6VR[)T%  
public SiteInfoBean() u4"r>e6 _B  
{//nSplitter的缺省值为5 <Jwo?[a  
//default value of nSplitter is 5 L8P 36]>  
this("","","",5); #v/ry)2Y=  
} l,bZG3,6  
wRbw  
.TN2s\:]jw  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) l2/ @<0P  
{ jgRCs.6  
sSiteURL= sURL; VO-784I  
sFilePath = sPath; qZsnd7o{l.  
sFileName = sName; VkXn8J  
this.nSplitter = nSpiltter; ~CFMIQ et  
Bz:0L1@,4a  
(j N]OE^  
} Wem?{kx0  
3+ asP&n  
iS-K ~qa  
public String getSSiteURL() /0\QL+^!  
{ HD00J]y_   
return sSiteURL; _LLshV3  
} 4x]NUt  
hAAUecx  
Mjw[:70  
public void setSSiteURL(String value) {PmzkT}LF  
{ B\zoJg&7(  
sSiteURL = value; @_O3&ZK  
} 04\Ta  
..$>7y}  
a7 )@BzF#  
public String getSFilePath() LDX y}hm)  
{ ?N _)>&b  
return sFilePath;  T{Hf P  
} Oga1u  
G5u meqYC  
n)CH^WHL&  
public void setSFilePath(String value) 88YC0!Ni  
{ 'FxYMSZS$  
sFilePath = value; BvJ\x)  
} ^0eO\wc?O  
ybYXD?  
-x?Hj/  
public String getSFileName() D(@SnI+  
{ \E&thp  
return sFileName; JP%RTGu  
} jrcc  
Rk{$S"8S_  
@Yarz1  
public void setSFileName(String value) `skH-lk,  
{ J ~'~[,K  
sFileName = value; S5/p=H:  
} *vD/(&pQ1:  
E6Q91Wz9f  
QRiF!D)Nk  
public int getNSplitter() 5iv@@1c  
{ `.`FgaJ |  
return nSplitter; APOea  
} ZmP1C`>  
o{g@Nk'f  
VLx T"]f  
public void setNSplitter(int nCount) iz(m3k:w  
{ C#T)@UxBZ  
nSplitter = nCount; .W-=x,`hY4  
} pKYLAt+^>  
} BArJ"t*/z  
3l+|&q[v  
(E IRz>  
/* F*. /D~K  
**Utility.java \CDAFu#  
*/ P 4H*jy@?  
package NetFox; a YR\<02  
9M nem*  
Bd QQ9$@5  
public class Utility { k=FcPF"  
pBvo M={2!  
W*3o|x   
public Utility() Ipg\9*c`  
{ ym[+Rw  
,A^L=+  
9M;I$_U`vj  
} {#0Tl  
% hNn%Oy:E  
//线程睡眠 2-PI JO  
public static void sleep(int nSecond) @_(nd57oSs  
{ EI<"DB   
try{ R:BBF9sK?  
Thread.sleep(nSecond); KZi+j#7O  
} H]U "+52h  
catch(Exception e) @ljZw(  
{ U:J /\-  
e.printStackTrace (); <kROH0+  
} D . 77WjwQ  
} F6~b#Jz&i  
F61 +n!%8  
//日志 >[ @{$\?x:  
public static void log(String sMsg) p-a]"l+L  
{ _pJX1_vD  
System.err.println(sMsg); fO0- N>W'P  
} *P&OxVz  
?Z5$0-g'hU  
uAChu]  
public static void log(int sMsg) =":@Foa  
{ IM$ 'J  
System.err.println(sMsg); LxIuxt=X|p  
} `Nkx7Z~w:  
} T3 =)F%  
o:h)~[n|  
byp.V_a}/  
/* W5TqC  
**TestMethod.java #cR57=M}  
*/ twAw01".  
package NetFox; p0"BO4({{  
U9bFUK/z  
TeOFAIU  
public class TestMethod { FW/6{tm  
1a \=0=[  
M_yZR^;^-  
public TestMethod() {c.}fyN  
{ ///xx/weblogic60b2_win.exe N45 s'rF  
try{ OX'/?B((  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ^.nwc#  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); (L]T*03#  
SiteFileFetch fileFetch = new SiteFileFetch(bean); D-;J;m \  
fileFetch.start(); BASO$?jf4  
} /M5=tW#e  
catch(Exception e){e.printStackTrace ();} :h3#1fko  
,oy4V^B&  
F^4*|g  
} B(HNB\3u  
h}Fu"zK  
0]f?Dx/8  
public static void main(String[] args) !.x=r  
{ :/n ?4K^  
new TestMethod(); fo/(()  
} MZgmv  
} k i~Raa/e  
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