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http断点续传简单实现(java)

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/* vo( j@+dz  
**SiteFileFetch.java &fd4IO/O  
*/ ng&EGM  
package NetFox; .dKRIFo  
import java.io.*; j_a~)o-p  
import java.net.*; *A1TDc$  
zyp"*0zUr  
a6k(O8Ank3  
public class SiteFileFetch extends Thread { >pH775I=  
S_ -QvG2  
sQw`U{JG  
SiteInfoBean siteInfoBean = null; //文件信息Bean , w'$T)  
long[] nStartPos; //开始位置 lKhh=Pc2  
long[] nEndPos; //结束位置 gUszMhHX  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 7+!7]'V  
long nFileLength; //文件长度 cJWfLD>2_!  
boolean bFirst = true; //是否第一次取文件 -z 5k4Y  
boolean bStop = false; //停止标志 whm tEY  
File tmpFile; //文件下载的临时信息 }B '*8^S  
DataOutputStream output; //输出到文件的输出流 ;7n*PBUJJ  
CygV_q  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) )< a8a@  
public SiteFileFetch(SiteInfoBean bean) throws IOException "`3 ^M vC  
{ 6p=xgk-q  
siteInfoBean = bean; q>:&xR"ra  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); =O'%)Y&  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); +$QL0|RL  
if(tmpFile.exists ()) Y7V&zF{  
{ Nx (pJp{S  
bFirst = false; j% USu+&  
read_nPos(); ,Ho.O7H  
} b G5  
else = 4WZr  
{ -QI`npsnV  
nStartPos = new long[bean.getNSplitter()]; ~5!TV,>ls  
nEndPos = new long[bean.getNSplitter()]; cTa D{!zm5  
} y'O{8Q8T  
G{Enh<V  
VrE5^\k<a  
+M]8_kE=+l  
} "sx&8H"  
J9=0?^v-:B  
[gdPHXs  
public void run() *#^1rKGWK  
{ 5 ^z ,'C  
//获得文件长度 gI5nWEM0{  
//分割文件 MV d 3*  
//实例FileSplitterFetch yi;t  
//启动FileSplitterFetch线程 3X,{9+(F  
//等待子线程返回 DF|lUO]:  
try{ _O,ZeES  
if(bFirst) }Q^a.`h  
{ ^|{fB,B  
nFileLength = getFileSize(); JsEEAM:w  
if(nFileLength == -1) >D4Ez  
{ 5g>kr< K  
System.err.println("File Length is not known!"); k[)@I;m  
} .%Q Ea_\  
else if(nFileLength == -2) hBE>ea  
{ &E`Z_} ~  
System.err.println("File is not access!"); i O|,,;_  
} 5w{pX1z1  
else Y mjS!H  
{ 9?$!=4  
for(int i=0;i<nStartPos.length;i++) $QBUnLOek&  
{ l*H"]6cXRL  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Z?' |9FM  
} jUSr t)o03  
for(int i=0;i<nEndPos.length-1;i++) r['C.S6  
{ -Ep6 .v  
nEndPos = nStartPos[i+1];  " 1Aus  
} : X|7l?{xW  
nEndPos[nEndPos.length-1] = nFileLength; 't.F.t  
} S Tk#hhx  
} j1+Y=@MA  
Vp{2Z9]}  
Z@/5~p  
//启动子线程 =W*`HV-w  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; nW'x#0-  
for(int i=0;i<nStartPos.length;i++) ~GYtU9s5  
{ 9W$)W  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), *S_Iza #&x  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), }8#Czo jt  
nStartPos,nEndPos,i); [`\Qte%UH  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Vnb#N4vR  
fileSplitterFetch.start(); IuW10}"9  
} (C@@e'e  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 0Jh:6F  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); "QS7?=>*F  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", P\e%8&_U/  
nEndPos = " + nFileLength); (Lnh> '2  
// fileSplitterFetch[nPos.length-1].start(); j83 V$ Le  
sXu+F2O  
9l]IE,u  
//等待子线程结束 :TI1tJS~*  
//int count = 0; >k|[U[@  
//是否结束while循环 ? Q}{&J  
boolean breakWhile = false; )K~nZLULY  
hgGcUpJy?  
A4' aB0^  
while(!bStop) ( Iew%U  
{ a0.XJR{T"  
write_nPos(); f6 nltZ  
Utility.sleep(500); _wCSL.  
breakWhile = true; n} {cs  
bAp`lmFI  
<lR8MqjM_  
for(int i=0;i<nStartPos.length;i++) 2|BE{91  
{ d%bL_I)  
if(!fileSplitterFetch.bDownOver) qv\yQ&pj  
{ t ,$)PV  
breakWhile = false; WM26-nR  
break; ~\P.gSiz  
} Kl?1)u3^4  
} ] ?(=rm9u  
if(breakWhile) G<'S  
break; {Hu0  
CR<l"~X  
h%%'{^>~  
//count++; EcU9Tm`h  
//if(count>4) V 6F,X`7  
// siteStop(); 0W> ",2|z  
} V QI7lJV"  
)1/O_N6C  
U*cj'`eqC  
System.err.println("文件下载结束!"); o=ex{g(3  
} h.nzkp5  
catch(Exception e){e.printStackTrace ();} b11C3TyQT  
} a'BBp6  
Sc&_6} K  
L6T_&AiL$  
//获得文件长度 D$ \ EZ   
public long getFileSize() bTj,5,8 i  
{ "TPMSx&Ei  
int nFileLength = -1; Z_%>yqDC  
try{ o&=m]hKpQl  
URL url = new URL(siteInfoBean.getSSiteURL()); y03l_E,  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); +xMDm_TGLA  
httpConnection.setRequestProperty("User-Agent","NetFox"); 945psG@|  
i> ;G4  
gIeo7>u  
int responseCode=httpConnection.getResponseCode(); _wIAr  
if(responseCode>=400) Ae1},2py  
{ N}\i!YUD  
processErrorCode(responseCode); 95}"AIi  
return -2; //-2 represent access is error ]^!#0(  
} ZP1EO Z  
?pFHpz   
- 0zo>[c/p  
String sHeader; 1*Z}M%  
T"O!  
!)GPI?{^5  
for(int i=1;;i++) X:YxsZQ 5Y  
{ fYwumx`J  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); gbvBgOp  
//Utility.log(in.readLine()); 7\.5G4dr%  
sHeader=httpConnection.getHeaderFieldKey(i); "YivjHa7H  
if(sHeader!=null) X]N8'Yt  
{ x[]n\\a?  
if(sHeader.equals("Content-Length")) mWZV O,t$  
{ 9rhz#w  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); W*P/~U=  
break; f.!cR3XgV  
} 6uDNqq  
} \eN}V  
else ;(z0r_p<q  
break; #6JG#!W  
} W)KV"A3C  
} ZW2U9  
catch(IOException e){e.printStackTrace ();} !aLL|}S  
catch(Exception e){e.printStackTrace ();} T3\Q<  
^s^X nQhE  
g1Aq;Ah/  
Utility.log(nFileLength); dD=dPi#  
xand%XNv  
h 9No'!'!  
return nFileLength; "/K44(^  
} }z}oVc  
d>2>mT$U  
b?y3m +V`  
//保存下载信息(文件指针位置) 9mr99 tA  
private void write_nPos() leiP/D6s  
{ XJ.vj+XXb  
try{ Ok9XC <Xu  
output = new DataOutputStream(new FileOutputStream(tmpFile)); #5F\zeo@F?  
output.writeInt(nStartPos.length); 23zB@aE_?1  
for(int i=0;i<nStartPos.length;i++) d&F8nBIM5  
{ G>"w$Us  
// output.writeLong(nPos); k\A8Z[  
output.writeLong(fileSplitterFetch.nStartPos); S_WYU&8  
output.writeLong(fileSplitterFetch.nEndPos); 0m!+gZ@  
} phd,Jg[  
output.close(); 3s" Rv@  
} IF<pT)  
catch(IOException e){e.printStackTrace ();} u[})|x*N  
catch(Exception e){e.printStackTrace ();} bP(xMw<'j  
} 8ex{N3  
}!x\qpA  
(]1n!  
//读取保存的下载信息(文件指针位置) qy"#XbBeV  
private void read_nPos() M#UW#+*g!  
{ a?_N8|k[  
try{ 6Gwk*%sb  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 2/3,%5j_  
int nCount = input.readInt(); O$+0 .  
nStartPos = new long[nCount]; -r7*C :E  
nEndPos = new long[nCount]; %N04k8z  
for(int i=0;i<nStartPos.length;i++) o[X 'We;  
{ x[zt(kC0+  
nStartPos = input.readLong(); 2Gd.B/L6  
nEndPos = input.readLong(); (]>= y  
} vvwNJyU-  
input.close(); kZfa8w L]P  
} k?ZtRhPu3X  
catch(IOException e){e.printStackTrace ();} ]yy10Pk[!  
catch(Exception e){e.printStackTrace ();} {1Z8cV   
} $hXhq*5|c  
iv*`.9TK-  
hCS|(8g  
private void processErrorCode(int nErrorCode) kr[p4X4  
{ ErnjIx:  
System.err.println("Error Code : " + nErrorCode); @i U@JE`C  
} fMgB!y"Em  
5)bf$?d   
j51Wod<[  
//停止文件下载 LlKvi_z  
public void siteStop() e)"] H*  
{ o`,|{K$H  
bStop = true; O/ Yz6VQ  
for(int i=0;i<nStartPos.length;i++) TrD2:N}dI  
fileSplitterFetch.splitterStop(); z><u YO$  
'RZ=A+%X  
++1<A& a  
} mCah{~  
} B8_)I.  
//负责部分文件的抓取 ;r'y/ Y'?  
**FileSplitterFetch.java lOB*M!8   
*/ jd ]$U_U(  
package NetFox; =A[:]),v  
4 JC*c  
jT/}5\  
import java.io.*; ML eo3  
import java.net.*; c$fi3O  
0oR'"Vo  
Zfwhg4G~  
public class FileSplitterFetch extends Thread { *WTmS2?'h  
S\wh *'Y  
FVY$A =G  
String sURL; //File URL p=13tQS<  
long nStartPos; //File Snippet Start Position cl2+,!:  
long nEndPos; //File Snippet End Position a* 2*aH7  
int nThreadID; //Thread's ID 'OEh'\d+x  
boolean bDownOver = false; //Downing is over '?$N.lj$d  
boolean bStop = false; //Stop identical MC\rx=cR\  
FileAccessI fileAccessI = null; //File Access interface ayGYVYi  
4S9hz  
\Dn47V{7-  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException M8Tj;ATr  
{ (g(.gN]  
this.sURL = sURL; l  rRRRR  
this.nStartPos = nStart; vH[G#A~4  
this.nEndPos = nEnd; I| V yv  
nThreadID = id; 8)KA {gN}  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Nj5V" c  
} :6h$1 +6  
 iwiHw  
TK! D=M  
public void run() P }BU7`8  
{ D6Q6yNE  
while(nStartPos < nEndPos && !bStop) |M;tAG$,"y  
{ A,H|c="  
=P}BAJ  
mK Ta.  
try{ l^~E+F~  
URL url = new URL(sURL); 0aWy!d  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); # .j[iN :+  
httpConnection.setRequestProperty("User-Agent","NetFox"); BdMmeM2h  
String sProperty = "bytes="+nStartPos+"-"; }piDg(D  
httpConnection.setRequestProperty("RANGE",sProperty); #E'aa'P}  
Utility.log(sProperty); - WEEnwZ  
<i1.W !%  
isF jJPe  
InputStream input = httpConnection.getInputStream(); 178u4$# b  
//logResponseHead(httpConnection); J$+K't5BZ  
W]TO%x{  
HNMVs]/e  
byte[] b = new byte[1024]; 4tGP- L  
int nRead; bdxmJ9a:R  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) VX'cFqrK3  
{ S.)+C2g,@  
nStartPos += fileAccessI.write(b,0,nRead); )ZHo7X  
//if(nThreadID == 1) ^q@6((O  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); XX9u%BZ~  
} ,suC`)R  
WVMkLMg8d  
r5s$#,O/&Q  
Utility.log("Thread " + nThreadID + " is over!"); h%=>iQ%enc  
bDownOver = true; )a;ou>u  
//nPos = fileAccessI.write (b,0,nRead); j34L*?  
} tqMOh R  
catch(Exception e){e.printStackTrace ();} =7l'3z8  
} _oU}>5  
} :enmMB#%  
WF&?OHf2  
 y5!fbmf  
//打印回应的头信息 Xlp$ xp"  
public void logResponseHead(HttpURLConnection con) +<TnE+>j  
{ s0/[mAY  
for(int i=1;;i++) "'9[c"Iz  
{ H}f} Y8J{  
String header=con.getHeaderFieldKey(i); ?z/ )Hkw  
if(header!=null) ^ALR.N+<  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ]N#%exBVo  
Utility.log(header+" : "+con.getHeaderField(header)); /t $J<bU  
else {wS)M  
break; pf%B  
} i^I U)\   
} K:_5#!*^98  
C\RJ){dk  
= VFPZ  
public void splitterStop() KhFw%Z0s<  
{ )^q7s&p/  
bStop = true; #|ILeby  
} !h[xeLlU  
O dWZYWj  
R32A2Ml  
} -w3KBlo  
/ZpwJc`e  
+yO^,{8SE  
/* wx]r{  
**FileAccess.java W5c?f,  
*//文件访问(定位,写) ,!i!q[YkL9  
package NetFox; O3];1ud  
import java.io.*; M0$wTmXM  
,%!E-gr  
{<J(*K*\Jo  
public class FileAccessI implements Serializable{ Dqz9NB  
A6faRi703  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 WNo",Vc  
RandomAccessFile oSavedFile; 90rY:!e  
long nPos; TTQ(\l4  
D&C83^m  
1v2pPUH\  
public FileAccessI() throws IOException "u=U@1 ^  
{ qy$1+>f1  
this("",0); e4rhB"qQdn  
} M%S.Z4D (0  
Ao}J   
3l?-H|T  
public FileAccessI(String sName,long nPos) throws IOException  >M-ZjT>  
{ S#g=;hD  
oSavedFile = new RandomAccessFile(sName,"rw"); ZBcT@hxm  
this.nPos = nPos; GDBxciv  
oSavedFile.seek(nPos); j$Unw  
} _`LQnRp(  
n |Is&fy  
=bDy :yY}  
public synchronized int write(byte[] b,int nStart,int nLen) sn=_-uoU  
{ PY{])z3N  
int n = -1; =U)e_q  
try{ /ltGSl  
oSavedFile.write(b,nStart,nLen); f.X<Mo   
n = nLen; W]l&mr  
} uFH ]w] X  
catch(IOException e) ~o?(O1QY  
{ )e6)~3[^  
e.printStackTrace (); W2 p&LP  
} B^yA+&3HI  
}_ [Bp  
N-cLp}D}WB  
return n; 1GA$nFBVC  
} .*_uXQ  
[<H'JsJl  
2zQ62t}  
} \cKY{(E  
pjVF^gv,*  
YKtF)N;m]  
/* E Qn4+  
**SiteInfoBean.java =FfxHo1k  
*/ <{xU.zp'  
package NetFox; Aq~}<qkIF+  
N# ?}r>W3  
c"H59 jE  
public class SiteInfoBean { %hM8px4d  
XNd%3rm,  
qS.TVNZ  
private String sSiteURL; //Site's URL /yhGc}h  
private String sFilePath; //Saved File's Path Y(D&JKx  
private String sFileName; //Saved File's Name }>T$2"pf  
private int nSplitter; //Count of Splited Downloading File yR|Beno  
IA$)E  
[>^xMF]$2  
public SiteInfoBean() 0[SJ7k19  
{//nSplitter的缺省值为5 (^)" qs B  
//default value of nSplitter is 5 rr;p;  
this("","","",5); =}h8Cl{H/  
} #MwNyZ  
md.#n  
vy&< O  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ,k=1 '7d  
{ CR KuN  
sSiteURL= sURL; KOqp@K$  
sFilePath = sPath; uOU?-WtPz  
sFileName = sName; 93+p~?  
this.nSplitter = nSpiltter; ZM$}Xy\9  
P}dhpU  
ud}B#{6  
} FdZG%N>Z  
AR}q<k6E  
Gs7#W:e7  
public String getSSiteURL() wy)I6`v  
{ F9Y/Z5 Ea  
return sSiteURL; T+9#&  
} D%k`udz<  
[`'[)B  
e.<y-b?  
public void setSSiteURL(String value) N4z(2.  
{ 3$E\B=7/U  
sSiteURL = value; M1sR+e$"  
} `fA|])3T  
rEl bzL"&<  
4PVkKP'/  
public String getSFilePath() ecjjCt2S  
{ ED>T2.:{  
return sFilePath; sp VE'"^  
} pMfP3G7V  
B > sTM  
l_`DQ8L`  
public void setSFilePath(String value) ^/k`URQ  
{ Le*sLuxk<  
sFilePath = value; T9,T'y>BD  
} G{8>  
/1Q i9uit  
HRPNZ!B  
public String getSFileName() [nBdq"K  
{ N=`xoF  
return sFileName; D02_ Jrg  
} W%)uKQha  
@H?_x/qBT  
:())%Xu3  
public void setSFileName(String value) x-Cy,d:YX  
{ 2?)bpp$WZ  
sFileName = value; XehpW}2\  
} w=r3QKm#K  
}.uB6&!:  
ns{BU->f  
public int getNSplitter() mM&*_#( 6  
{ ~;pv &s5}  
return nSplitter; -}h+hS50F  
} bg8<}~zg  
x@@U&.1_A  
*i}Nb* Z3  
public void setNSplitter(int nCount) Mk*&CNo3  
{ #..-!>lY  
nSplitter = nCount; d]v4`nc  
} ZW]Q|vPh4U  
} I^5T9}>Q  
LOD'iiH6  
f-V8/  
/* ; U)a)l'y  
**Utility.java i&r56m<  
*/ =s2dD3Fr|  
package NetFox; y5XHJUTu  
Dn 6k,nVh  
&*I\~;1  
public class Utility { o4)^U t+  
x<0-'EF/S  
yAu-BObD  
public Utility() 'wo[iNy[  
{ q/o|uAq  
n\nC.|_G@  
e7{n=M  
} AC=/BU3<yc  
6,"fH{Bd  
//线程睡眠 Y* #'Gh,  
public static void sleep(int nSecond) VQm)32'  
{ iY=M67V  
try{ OHqc,@a;+  
Thread.sleep(nSecond); wAr (5nEbx  
} RLypWjMx$  
catch(Exception e) [<)/ c>Y  
{ avR4#bfc  
e.printStackTrace (); ; &2J9  
} &%~2Wm  
} apxZ}  
{emO&#=@CP  
//日志 xw*T? !r=V  
public static void log(String sMsg) 5!ll #/ {`  
{ {x $H# <Y  
System.err.println(sMsg); /znW$yh o  
} kL.JrbM"  
JM5 w`=  
SxMrX C*  
public static void log(int sMsg) 0`=#1u8  
{ "5mdq-h(  
System.err.println(sMsg); $_-f}E  
} \(t.|  
} n*6b*fl  
N|c;Qzl  
QN_Zd@K*A  
/* :CO>g=`  
**TestMethod.java 6(4FC?Y7  
*/ nB?$W4  
package NetFox; w/r wE  
.__X- +^  
.jRp.U  
public class TestMethod { UY*3b<F}  
0c4H2RW  
1 dT1DcZ  
public TestMethod() G>{Bij44  
{ ///xx/weblogic60b2_win.exe @Otom'O  
try{ A-\OB Nh  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); V`Z-m-V~1  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); _}.BZ[i  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ^)Xl7d|m+  
fileFetch.start(); <Q'J=;vV  
} 9L;fT5Tp7  
catch(Exception e){e.printStackTrace ();} {-IH?!&v  
G2Eke;  
[mKPOg-t  
} <zE,T@c  
lz.ta!6  
_p/ _t76s  
public static void main(String[] args) !Mp.jE  
{ X4LU/f<f  
new TestMethod(); bD[W`yW0  
} I/D (gY06<  
} 5y;texsj[  
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