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http断点续传简单实现(java)

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/* Xb)XV$0  
**SiteFileFetch.java T 7Lk4cU  
*/ @>(l}5U5  
package NetFox; &,{cm^*  
import java.io.*; #++MoW}'g  
import java.net.*; &p=|z2 J  
F! c%&Z  
x>&1;g2r  
public class SiteFileFetch extends Thread { TnPdpynP  
HPVT$EJ  
.7+_ubj&,  
SiteInfoBean siteInfoBean = null; //文件信息Bean wV W+~DJ  
long[] nStartPos; //开始位置 (aiE!c  
long[] nEndPos; //结束位置 42U3>  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 W%Br%VQJ  
long nFileLength; //文件长度 frc>0\  
boolean bFirst = true; //是否第一次取文件 3M+hjc.  
boolean bStop = false; //停止标志 3/}=x<ui  
File tmpFile; //文件下载的临时信息 L a0H  
DataOutputStream output; //输出到文件的输出流 NZi5rX N  
- FA#hUK$  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) qB<D'h7  
public SiteFileFetch(SiteInfoBean bean) throws IOException  6.KR(V  
{ JAmv7GL'6  
siteInfoBean = bean; 76zi)f1f  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); &q``CCOF&  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); `"A\8)6-  
if(tmpFile.exists ()) Zhz.8W  
{ Zo-s_6uC  
bFirst = false; I&Yu=v/_  
read_nPos(); L7q%u.nB1  
}  6>Lr  
else O'$0K0k3  
{ r\ ` R$  
nStartPos = new long[bean.getNSplitter()]; AM'-(x|  
nEndPos = new long[bean.getNSplitter()]; 3$(1LN  
} 'u_'y  
QmbD%kW`3  
S[X bb=n  
M2my>  
} $ LFzpg  
@"'1"$  
y?CEV-3+  
public void run() 19 bP0y  
{ f o4j^,`  
//获得文件长度 `Qaw]&O  
//分割文件 'WxcA)z0cQ  
//实例FileSplitterFetch l_>^LFOA  
//启动FileSplitterFetch线程 8 yB  
//等待子线程返回 uDQ d48>  
try{ H5^ 'J`0\  
if(bFirst) J3S@1"   
{ 2@uo2]o)  
nFileLength = getFileSize(); "eZNci  
if(nFileLength == -1) sW3-JA]  
{ 0K@s_C=n#  
System.err.println("File Length is not known!"); {p yo  
} $@}6P,mg  
else if(nFileLength == -2) |a3)U%rUEQ  
{ pWwaN4  
System.err.println("File is not access!"); $-jj%x\}  
} <M7@JgC &  
else :&&Ps4\Sq  
{ qyp"q{k0  
for(int i=0;i<nStartPos.length;i++) T$0//7$')  
{ ,]y)Dy  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); hi`\3B  
} R l^ENrv!]  
for(int i=0;i<nEndPos.length-1;i++) 3oE *86  
{ najd~%?Rs  
nEndPos = nStartPos[i+1]; v?-pAA)ht  
} m~(]\  
nEndPos[nEndPos.length-1] = nFileLength; Rkw)IdB  
} Y>R|Uf.o z  
} "'^#I_*Mf  
W*}q;ub;  
;]KGRT  
//启动子线程 b H?dyS6Bx  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length];  #RbPNVs  
for(int i=0;i<nStartPos.length;i++) '7u#uL,pa1  
{ [-{L@  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), F?T3fINR  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 4WzB=C(f  
nStartPos,nEndPos,i); )+u|qT3%  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); CmY'[rI  
fileSplitterFetch.start(); Gv?'R0s  
} "  F~uTo  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), C.}Z5BwS  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ZiSy&r:(  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", kQsyvE  
nEndPos = " + nFileLength); dAm( uJ  
// fileSplitterFetch[nPos.length-1].start(); LXJ"ct  
=S|SQz5%w  
9fzbR~s  
//等待子线程结束 5d*k[fZ  
//int count = 0; Y \& 4`v'  
//是否结束while循环 CLdLO u"  
boolean breakWhile = false; uG${`4  
 Ae <v  
IgG@v9'  
while(!bStop) n/=&?#m}d  
{ [JO'ta  
write_nPos(); {h7*a=  
Utility.sleep(500); 600-e;p  
breakWhile = true; BN|+2D+S  
HulN84  
4 "@BbVYR  
for(int i=0;i<nStartPos.length;i++) PHyS^J`  
{ %)i?\(/  
if(!fileSplitterFetch.bDownOver) p*-o33Ve  
{ T,TKt%  
breakWhile = false; rk-}@vp  
break; DSM,dO'  
} kK16+`\+  
} cr27q6_  
if(breakWhile) vMRM/.  
break; |F iL1_  
i(a2FKLy  
z5=&qo|f9l  
//count++; Yih^ZTf]O?  
//if(count>4) H8`K?SXU  
// siteStop(); TMhUo#`I|  
} 2(\~z@g  
CGbW] D$@  
vAy`8Q  
System.err.println("文件下载结束!"); 71z$a  
} ujXC#r&  
catch(Exception e){e.printStackTrace ();} WW:@%cQ@  
} #]_S{sO  
Qx>S>f  
/E2/3z  
//获得文件长度 j\P47q'v#  
public long getFileSize() w3:Y]F.ot  
{ _WVeb}  
int nFileLength = -1; Ja4O*C<  
try{ S =U*is  
URL url = new URL(siteInfoBean.getSSiteURL()); %A,4vLe~6  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 9mEC|(m*WK  
httpConnection.setRequestProperty("User-Agent","NetFox"); 17a'C  
+w?RW^:Q=  
$*Njvr7  
int responseCode=httpConnection.getResponseCode(); &DYHkG  
if(responseCode>=400) G[)Ll=  
{ CSN]k)\N(  
processErrorCode(responseCode); K=;z&E=<c  
return -2; //-2 represent access is error a-MDZT<xA+  
} 5)wz`OS  
razVO]]E  
q=M!YWz  
String sHeader; Hq?-e?Nc  
z:ue]7(.  
nr Jl>H  
for(int i=1;;i++) 7 M=LyrO  
{ y[UTuFv~Q  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); npkE [JE:  
//Utility.log(in.readLine()); yEJ}!/  
sHeader=httpConnection.getHeaderFieldKey(i); I8d#AVF2  
if(sHeader!=null) <{Wsh#7}.  
{ il(dVW  
if(sHeader.equals("Content-Length")) X2 c<.  
{ 9fp1*d  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); [[}KCND  
break; Du k v[/60  
} $z"3_4a  
} R*`A',]:9  
else i(Cd#1<  
break; 02g}}{be8  
} _Jn-#du  
} T\eOrWt/  
catch(IOException e){e.printStackTrace ();} t4R=$ km  
catch(Exception e){e.printStackTrace ();} aze}ko NE  
Ms ;:+JI  
bF;g.-.2  
Utility.log(nFileLength); +!\$SOaR{  
R3`!Xj#&M  
ne4j_!V{Mf  
return nFileLength; 2%y}El^+_  
} _5uzu6:y  
_Qs=v0B//  
^31X-}t v  
//保存下载信息(文件指针位置) Q&}`( ]k  
private void write_nPos() -& I)3  
{ -/*-e /+b  
try{ ] mYT!(}  
output = new DataOutputStream(new FileOutputStream(tmpFile)); v) mO"\  
output.writeInt(nStartPos.length); 9YS&RBJu  
for(int i=0;i<nStartPos.length;i++) &x =}m  
{ _5 Zhv-7  
// output.writeLong(nPos); >T[1=;o]  
output.writeLong(fileSplitterFetch.nStartPos); PE4#dx^  
output.writeLong(fileSplitterFetch.nEndPos); ~mP#V  
} \R#]}g0!  
output.close(); bnt>j0E  
} 1K.i>]}>  
catch(IOException e){e.printStackTrace ();} Q%o:*(x[O  
catch(Exception e){e.printStackTrace ();} w#_/CU L  
} PTfTT_t  
o(Yj[:+m  
T$RVz   
//读取保存的下载信息(文件指针位置) }ac0}  
private void read_nPos() O>9+ tQ  
{ f'` QW@U  
try{ 4 8l!P(>?y  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Q>]FO  
int nCount = input.readInt(); l ?RsXC  
nStartPos = new long[nCount]; FvQ>Y')R7Z  
nEndPos = new long[nCount]; #!(OTe L  
for(int i=0;i<nStartPos.length;i++) 6}zargu(;  
{ c193Or'6Y  
nStartPos = input.readLong();  MO|aN,  
nEndPos = input.readLong(); BO)K=gl;8  
} :Lu=t3#  
input.close(); W9nmTz\8  
} LxaR1E(Cc'  
catch(IOException e){e.printStackTrace ();} qOAK`{b  
catch(Exception e){e.printStackTrace ();} Qxr&zT7f  
} T|RW-i3  
w7aC=B/{?i  
\6~(# y  
private void processErrorCode(int nErrorCode) ~ HFDX@m*  
{  0IO#h{t  
System.err.println("Error Code : " + nErrorCode); OP>rEUtj  
} 4d~Sn81xW  
-8H0f- 1  
(`<X9w,  
//停止文件下载 f'._{"  
public void siteStop() w ryjs!  
{ "l0z?u  
bStop = true; j_ i/h "  
for(int i=0;i<nStartPos.length;i++) s3?pv  
fileSplitterFetch.splitterStop(); r/E'#5 Q  
qk!")t  
#Duz|F+%  
} hZ6CiEJB  
} #;,dk(URo  
//负责部分文件的抓取 :=9?XzCC  
**FileSplitterFetch.java =s3f{0G  
*/ JtA tG%  
package NetFox; P?D;BAP2  
}Jfi"L  
Ch;C\H:X  
import java.io.*; P(B:tg  
import java.net.*; KtH-QQDluj  
Bs7/<$9K/  
mT  enzIp  
public class FileSplitterFetch extends Thread { /sHWJ?`&/,  
4E\Jk5co,  
!U,W; R  
String sURL; //File URL l Q/u#c$n  
long nStartPos; //File Snippet Start Position x`:zC#  
long nEndPos; //File Snippet End Position (prqo1e@  
int nThreadID; //Thread's ID :2^j/  
boolean bDownOver = false; //Downing is over 6yZ!K  
boolean bStop = false; //Stop identical <Sw>5M!j  
FileAccessI fileAccessI = null; //File Access interface DLMM1 A  
rZ}y'A   
(`%$Aa9J  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException c!#DD;<Q  
{ Wc] L43u  
this.sURL = sURL; lxsBXXZg  
this.nStartPos = nStart; Wl!|+-  
this.nEndPos = nEnd; ;#c=0*.  
nThreadID = id; OX|nYTp  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Dxj&9Ra  
} x%<oeM3U  
Y*oT (  
6, =oTmFP  
public void run() NJ" d`  
{ :f1Q0klwP  
while(nStartPos < nEndPos && !bStop) (vL-Z[M!  
{ v8=7  
,D#ssxV  
II(7U3  
try{ X'BFR]cm  
URL url = new URL(sURL); ca~nfo  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); @nIoYT='  
httpConnection.setRequestProperty("User-Agent","NetFox"); @&H Tt  
String sProperty = "bytes="+nStartPos+"-"; liu%K9-r  
httpConnection.setRequestProperty("RANGE",sProperty); eAvOT$  
Utility.log(sProperty); 6KT]3*B   
}@VdtH  
q o,uOi  
InputStream input = httpConnection.getInputStream(); LRe2wT>I  
//logResponseHead(httpConnection);  ! n@*6  
A}K2"lQ#>,  
ib$_x:OO"  
byte[] b = new byte[1024]; lN@SfM4\  
int nRead; ;fg8,(SM^  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 8#?jYhT7  
{ +OGa}9j-  
nStartPos += fileAccessI.write(b,0,nRead); rK^Sn7U  
//if(nThreadID == 1) (- ]A1WQ?  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); %qN_<W&Ze  
} Pr|:nJs  
d"h*yH@  
CJ'pZ]\G  
Utility.log("Thread " + nThreadID + " is over!"); 53vnON#{*  
bDownOver = true; 6;|6@j  
//nPos = fileAccessI.write (b,0,nRead); Id_?  
} yWsJa)e3*@  
catch(Exception e){e.printStackTrace ();} uU+R,P0  
} kH&KE5  
} 8v eG^o  
7t8[M(  
k(<:  
//打印回应的头信息 '!$g<= @  
public void logResponseHead(HttpURLConnection con) d46PAA{'  
{ ,\t:R1.  
for(int i=1;;i++) 0Fd<@w Q0  
{ *RPdU.  
String header=con.getHeaderFieldKey(i);  -)='htiU  
if(header!=null) 2>bTcud>  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); oRJ!J-Z]  
Utility.log(header+" : "+con.getHeaderField(header)); kX0hRX  
else p_ H;|m9  
break; vUlGE  
} PAYbsn  
} D/& 8[Z/Cn  
iR_j h=2{  
}@+3QHwYU  
public void splitterStop() N*vBu `  
{ '{e9Vh<x  
bStop = true; pb>TUKvT&  
} 6oh\#v3zV  
r8]y1 Om<  
V5]}b[X  
} "4`i]vy8  
5" 5tY  
%3"xn!'vf  
/* osBwX.G'l  
**FileAccess.java pQ:7%+Om  
*//文件访问(定位,写) ;F)j,Ywi)H  
package NetFox; QJeL&mf  
import java.io.*; '>8IOC  
_zuaImJ0o  
H8$l }pOz  
public class FileAccessI implements Serializable{ CxvL!ew  
yJyovfJz.  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 V'-}B6 3S>  
RandomAccessFile oSavedFile; ?W6qwm,?L  
long nPos; nTG@=C#  
{Kbb4%P+h  
@y"/hh_?  
public FileAccessI() throws IOException F_<n8U:Y  
{ df85g  
this("",0); 8[PD`*w  
} [ 2WJ];FJ  
{~L{FG)O  
;7;=)/-  
public FileAccessI(String sName,long nPos) throws IOException +-s$Htx  
{ eUY/H1  
oSavedFile = new RandomAccessFile(sName,"rw"); { :^;byd  
this.nPos = nPos; -k4w$0)  
oSavedFile.seek(nPos); R]LRgfi9  
} 5o v F$qn  
D7X8yv1  
&3@ {?K  
public synchronized int write(byte[] b,int nStart,int nLen) 6}(; ~/L  
{ %a'Nf/9=:  
int n = -1; <`PW4zSI  
try{ a/@F?\A  
oSavedFile.write(b,nStart,nLen); FrKI=8  
n = nLen; ?h$ =]  
} @R c/ ^B:  
catch(IOException e) :!'!V>#g  
{ ?j'Nx_RoX  
e.printStackTrace (); Ht{Q=w/ 9  
} <6!;mb ;cX  
6k4ZzQ}  
hggP9I :s,  
return n; zp4aiMn1F  
} q=,  
6 h?v/\  
)\`.Ru~,  
} bjR:5@"  
b6]MJ0do  
3dl#:Si  
/* ?3duW$`  
**SiteInfoBean.java B.Szp_$  
*/ l?f%2:}m  
package NetFox; zUQn*Cio e  
, z-#B]  
4\#b@1]}  
public class SiteInfoBean { EC:u;2f!  
VR'R7  
'5f6 M^}|2  
private String sSiteURL; //Site's URL 7o99@K,  
private String sFilePath; //Saved File's Path :l;SG=scx  
private String sFileName; //Saved File's Name w3<%wN>tE  
private int nSplitter; //Count of Splited Downloading File 0gIJ&h6*f  
?q*,,+'0  
r;7&U<j~Z  
public SiteInfoBean() ]ChGi[B~9  
{//nSplitter的缺省值为5 ]%Db%A  
//default value of nSplitter is 5 :`Z'vRj  
this("","","",5); }hm "49,O  
} \]Nt-3|`0  
crDm2oA~t  
R(1N]>  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ##\ <mFE  
{ Xc}~_.]  
sSiteURL= sURL; ((AsZ$[S  
sFilePath = sPath; bTd94  
sFileName = sName; ,B'n0AO/'  
this.nSplitter = nSpiltter; ^e~m`R2fHh  
b}-/~l-:  
r8wip\[  
} # o;\5MOE%  
(fTi1 I!  
)q8!:Z  
public String getSSiteURL() OL2 b  
{ /[FES 78p  
return sSiteURL; |eu:qn8  
} *a[iq`499  
8q"C=t7  
te*|>NRS  
public void setSSiteURL(String value) ,|7!/]0&  
{ &OXWD]5$6  
sSiteURL = value; G@(ukt`0}  
} !A|ayYBb\  
 %&81xAt  
4e!>A  
public String getSFilePath() M3EB=tU  
{ D=!T,p=  
return sFilePath; l`b%imX  
} &UextGk7  
Iq% 0fX  
^}{`bw{  
public void setSFilePath(String value) ]nQC  
{ -LnNA`-  
sFilePath = value; -]-?>gkN5  
} hLo>jE  
AnW72|=A(  
.~C[D T+,  
public String getSFileName() nuucYm%IF-  
{ !]l!I9  
return sFileName; $j"TPkW{M  
} |9;MP&68  
Y2 oN.{IH  
LvcGh  
public void setSFileName(String value) Mv1V Vk  
{ ln*_mM/Q%  
sFileName = value; '7ps_pz  
} OGGuVY  
7.!`c-8 u  
fEYo<@5c]  
public int getNSplitter() ?E|be )  
{ 8)m  
return nSplitter; wF.S ,|  
} *D:"I!Ho  
&`}8Jz=S  
:OC(93d)0  
public void setNSplitter(int nCount) 2`V[Nb  
{ `U6bI`l  
nSplitter = nCount; .8~zgpK  
} PpWn+''M  
} SJd,l,Gg)  
i4g99Kvl  
XT<{J8 0z  
/* s4kkzTnXE3  
**Utility.java y7LT;`A  
*/ f{j.jfl\x  
package NetFox; c%O8h  
R;3Tyn+  
T!3_Q/~^r  
public class Utility { `ZLA=oD  
Yd>ej1<  
WVkJ=r0Ny  
public Utility() iL\eMa  
{ <`Q*I Y  
n| [RXpAp3  
jv5Os-  
} jC3)^E@:"  
8r-'m%l  
//线程睡眠 <}z, !w8  
public static void sleep(int nSecond) <7X6ULQ  
{ m@#@7[6]o  
try{ |h{#r7H0  
Thread.sleep(nSecond); 9+"\7MHw  
} mq!_/3  
catch(Exception e) Tu9[byfrI  
{ SGA!%=Lp  
e.printStackTrace (); ^Ss4<  
} ry[NR$L/m  
} P+s-{vv{0  
r_?il]l  
//日志 D8r=V f  
public static void log(String sMsg) ??g`c=R!V  
{ hrZ=8SrW  
System.err.println(sMsg); se,0Rvkt  
} 7$/%c{o  
idLCq^jnJ  
\UR/tlw+/  
public static void log(int sMsg)  aa10vV  
{ <RPy   
System.err.println(sMsg); 6d%'>^`(o-  
} [T>a}}@  
} <-%OXEG  
7$HN5T\!  
P3u,)P&  
/* 1~_&XNb&  
**TestMethod.java w=K!U]  
*/ { kF"<W  
package NetFox; szG0?e  
*LZ^0c:r  
vi-mn)L6#  
public class TestMethod { %I>-_el  
Or9`E(  
q(YFt*(;w  
public TestMethod() A=a~ [vre  
{ ///xx/weblogic60b2_win.exe -|\SNbPTV  
try{ *M^t@hl  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 2ij/!  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); QZ:xG:qyk;  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 0A. PfqYi  
fileFetch.start(); WymBjDos:  
} YnLwBJ2i  
catch(Exception e){e.printStackTrace ();} xw5LPz;B  
JRT,%;*,  
~3F\7%Iqc  
} 7\e96+j|f  
pS C5$a(  
;{e=Iz}/  
public static void main(String[] args) <>9zXbI  
{ ))z1T8  
new TestMethod(); 48  |u{  
} e_{!8u.+  
} 7HkQ|~zGT  
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