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http断点续传简单实现(java)

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/* wJAJ /  
**SiteFileFetch.java " ZYdJHM  
*/ o)]mJb~XG-  
package NetFox; RW4,j&)  
import java.io.*; ]I^b&N  
import java.net.*; h<0&|s*a)  
4roqD;5|~|  
eJ ;a}{ 4%  
public class SiteFileFetch extends Thread { b0| ;v-v  
ASU.VY  
ou\M}C`E  
SiteInfoBean siteInfoBean = null; //文件信息Bean b/soU2?^  
long[] nStartPos; //开始位置 V<A$eb>6  
long[] nEndPos; //结束位置 \ 9!hg(-F  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 -_?U/k(Hi  
long nFileLength; //文件长度 x>!bvZ2  
boolean bFirst = true; //是否第一次取文件 23p1Lb9P  
boolean bStop = false; //停止标志 ~W..P:wG5  
File tmpFile; //文件下载的临时信息 ks|c'XQb  
DataOutputStream output; //输出到文件的输出流 JYw_Z*L=m  
b4?]/Uy+/  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) ^:cc3wt'3[  
public SiteFileFetch(SiteInfoBean bean) throws IOException I<+i87=  
{ EA``G8Vn>  
siteInfoBean = bean; +bDBc?HZ{$  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 8\VP)<<  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ZJf:a}=h  
if(tmpFile.exists ()) Z#NEa.]  
{ sS{!z@\Lf  
bFirst = false; :9~LYJ ?  
read_nPos(); E' _6v  
} `i5\(cdl  
else MLT ^7'y  
{ UP .4#1I  
nStartPos = new long[bean.getNSplitter()]; r "uQ|  
nEndPos = new long[bean.getNSplitter()]; IY"+hHt  
} |>zYUT[V  
80GBkFjV  
dRL*TT0NW  
i9+qU  
} <ebC]2j8cK  
*Roqie  
UC@Jsj~f  
public void run() Z{}+7P  
{ evvv&$&  
//获得文件长度 s+<`iH9Hm  
//分割文件 K41Gn  
//实例FileSplitterFetch 3C gmZ7[  
//启动FileSplitterFetch线程 ty\F~]Oo  
//等待子线程返回 .%G>z"Xx  
try{ SpC6dkxD\  
if(bFirst) [/Sk+ID  
{ I} .9  
nFileLength = getFileSize(); s H(io  
if(nFileLength == -1) ]|_UpP8EP  
{ =/e$Rp  
System.err.println("File Length is not known!"); t2LX@Q"  
} I~F]e|Ehqr  
else if(nFileLength == -2) Ay@/{RZz  
{ g#%Egb1  
System.err.println("File is not access!"); T f40lv+{  
} 6an= C_Mb`  
else 6]|-%  
{ z'&tmje[?  
for(int i=0;i<nStartPos.length;i++) U1;&G  
{ _;mA(j  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); F*-+5nJ&@  
} b6NGhkr'\  
for(int i=0;i<nEndPos.length-1;i++) Y[0mTL4IO  
{ ,4HZ-|EOZ  
nEndPos = nStartPos[i+1]; puAjAvIax  
} Oq*;GR(Q  
nEndPos[nEndPos.length-1] = nFileLength; Oy_%U*  
} \7PC2IsT3  
} -&EU#Wqh  
A5E^1j}h@  
F4]=(T  
//启动子线程 `-w,6  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; WX* uhR  
for(int i=0;i<nStartPos.length;i++) 8o i{%C&-  
{ u<JkP <"S  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), x~QZVL=:  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 2. q\!V}yQ  
nStartPos,nEndPos,i); l4gZHMh'  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); #.{ddY{  
fileSplitterFetch.start(); kgHZaQnD  
} ?kULR0uL+  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), W3gHz T?{  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); "&C>=  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", O>"T*   
nEndPos = " + nFileLength); ~"VM_Lz]5  
// fileSplitterFetch[nPos.length-1].start(); ue1g(;  
F~sUfqiJ'  
f^)iv ]p  
//等待子线程结束 JAX`iQd  
//int count = 0; \h/)un5  
//是否结束while循环 ;}H*|"z;!  
boolean breakWhile = false; VVbFn9+V  
E[Q2ZqhgbP  
wGw<z[:f  
while(!bStop) op($+Q  
{ VCzb[.  
write_nPos(); G 2`hEX%  
Utility.sleep(500); ++ZP X'|  
breakWhile = true; a@ ^)?cH!z  
biG :Xn  
w7c0jIf{  
for(int i=0;i<nStartPos.length;i++) XS$#\UQ  
{ :_|Xr'n`A  
if(!fileSplitterFetch.bDownOver) ojyP.R  
{ D63?f\  
breakWhile = false; Z*n4$?%W  
break; qpjiQ,\:b  
} \]0#jI/:  
} C;?<WtH  
if(breakWhile) \dbaY:(  
break; GX=U6n>  
J"-/ok(<@  
7 lSR  
//count++; {:#c1d2@8  
//if(count>4) "E@A~<RKP  
// siteStop(); DzIV5FG  
} 6rM{r>  
5me#/NqLHY  
'Ck:=V%}g  
System.err.println("文件下载结束!"); LLL;SNY  
} Zrzv';  
catch(Exception e){e.printStackTrace ();} Yx&d\/9  
} a ?\:,5=  
H43d[@h  
Z<*"sFpAO  
//获得文件长度 hW9U%-D  
public long getFileSize() ,/qY 9eh  
{ T 0qM "  
int nFileLength = -1; c axOxRo\  
try{ d@tf+_Ih  
URL url = new URL(siteInfoBean.getSSiteURL());  A"1%E.1  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); }~p%e2<  
httpConnection.setRequestProperty("User-Agent","NetFox"); _gEojuaN  
_U9.u#>sV  
Jp c %i8  
int responseCode=httpConnection.getResponseCode(); /A+5q\8G  
if(responseCode>=400) /Ny#+$cfk  
{ hj\A-Yf  
processErrorCode(responseCode); bYmk5fpRG  
return -2; //-2 represent access is error &fsk ESV0  
} wD /jN:  
Dw>)\\n{Kl  
QQ=Kj%R  
String sHeader; <\$?.tTZ {  
&Xc=PQ:I  
)%<,JD  
for(int i=1;;i++) gD;T"^S+  
{ bM2x (E\O  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 96S$Y~G# &  
//Utility.log(in.readLine()); !K+hXQE1  
sHeader=httpConnection.getHeaderFieldKey(i); 1h#/8 X  
if(sHeader!=null) NZO86y/  
{ ac6@E4 _  
if(sHeader.equals("Content-Length")) :9e4(7~ona  
{ ("YWJJ'H  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); @NL37C  
break; 1!yd(p=cL  
} xLms|jS  
} Xpv<v[a  
else -zWNQp$  
break; D2J)qCK1)  
} C ^c <s  
} bc NyB$S  
catch(IOException e){e.printStackTrace ();} \qTp#sF  
catch(Exception e){e.printStackTrace ();} ^y%8_r&  
JDW/Mc1bh  
1Y%lt5,*  
Utility.log(nFileLength); -0TI7 @  
HXX9D&c4R  
a^\ F9^j  
return nFileLength; g}IOHE  
} zl|+YjR  
Qn~{TZz  
\y6Y}Cv  
//保存下载信息(文件指针位置) ko|M2\  
private void write_nPos() _v(5vx_ {  
{ #s ' `bF^  
try{ 2bG92  
output = new DataOutputStream(new FileOutputStream(tmpFile)); FS!9 j8  
output.writeInt(nStartPos.length); _z1Qr?cY  
for(int i=0;i<nStartPos.length;i++) 7IQa Xcl  
{ 'T(Q  
// output.writeLong(nPos); |onLJY7)  
output.writeLong(fileSplitterFetch.nStartPos); s Ytn'&$\  
output.writeLong(fileSplitterFetch.nEndPos); 4>2\{0r  
} O9m sPb:  
output.close(); zo("v*d*q  
} I[b{*g2Zw  
catch(IOException e){e.printStackTrace ();} F/,6Jh  
catch(Exception e){e.printStackTrace ();} "kC6G%  
} &ld<fa(w+2  
:5'hd^Q  
n*i&o;5  
//读取保存的下载信息(文件指针位置) T tnJ u*  
private void read_nPos() 97<Z,q72Y  
{ epG]$T![  
try{ 1]Cb i7  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); xFJT&=Af W  
int nCount = input.readInt(); wWSw0 H/  
nStartPos = new long[nCount]; a8v\H8@X  
nEndPos = new long[nCount]; >rSCf=  
for(int i=0;i<nStartPos.length;i++) C1(RgY|  
{ & P%#  
nStartPos = input.readLong(); ,izp^,`  
nEndPos = input.readLong(); Z op/ MeI  
} 4^k8| # c  
input.close(); Dx=RLiU9  
} 1r*yYm'  
catch(IOException e){e.printStackTrace ();} s&+`>  
catch(Exception e){e.printStackTrace ();} q(WGvl^r  
}  Lsai8 B  
.gN ziDO  
UtC<TBr  
private void processErrorCode(int nErrorCode) \ So)g)K  
{ P[$idRS&  
System.err.println("Error Code : " + nErrorCode); P.g./8N`z  
} Nq^o8q_  
OoRg:"9{#  
he@Y1CY  
//停止文件下载 <%W&xk  
public void siteStop() S,ud pQ7  
{ U>00B|<GJ  
bStop = true; kGC*\?<LmR  
for(int i=0;i<nStartPos.length;i++) ^CM@VmPp  
fileSplitterFetch.splitterStop(); `:R9M+ OX  
,_/\pX0  
O2yD{i#l*#  
} wDSwcNS  
} v-^<,|vm2f  
//负责部分文件的抓取 GMkni'pV  
**FileSplitterFetch.java 8|$g"? CU  
*/ 9~2iA,xs  
package NetFox; @HnahD  
osmCwM4O  
'66nqJb*  
import java.io.*; QFN9j  
import java.net.*; M?;YpaSe+  
90,UhNz9D  
;49sou  
public class FileSplitterFetch extends Thread { m6H+4@Z-;(  
@MoCEtt  
:cIPX%S  
String sURL; //File URL |}:q@]dC#  
long nStartPos; //File Snippet Start Position !6sR|c"~j  
long nEndPos; //File Snippet End Position O'xp"e,  
int nThreadID; //Thread's ID Os]. IL$  
boolean bDownOver = false; //Downing is over :oYSvK7>  
boolean bStop = false; //Stop identical 3q@H8%jcw  
FileAccessI fileAccessI = null; //File Access interface 69Z`mR  
7l09  
^^24a_+2  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException d_f*'M2Gv  
{ (&V)D?/hS  
this.sURL = sURL; .QA1'_9  
this.nStartPos = nStart; wlh%{l  
this.nEndPos = nEnd; L_+ Fin  
nThreadID = id; O*N:.|dUw  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ar'VoL}  
} m(1ot M9  
foY]RkW9  
<VQ@I  
public void run() &oJ[ *pQ  
{ NXz/1ut%  
while(nStartPos < nEndPos && !bStop) >HzTaXCR[  
{ kp!(e0n  
EFu$>Z4  
k Q_Vj7  
try{ 9x(t"VPuS  
URL url = new URL(sURL); &|Rww\oJ  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 7fd,I%v  
httpConnection.setRequestProperty("User-Agent","NetFox"); 9"L!A,&'  
String sProperty = "bytes="+nStartPos+"-"; { i4`- w  
httpConnection.setRequestProperty("RANGE",sProperty); ,6f6r  
Utility.log(sProperty); Se\iM s  
Q&@<?K9  
>}C:EnECy  
InputStream input = httpConnection.getInputStream(); 0C"2?etMx  
//logResponseHead(httpConnection); P!)F1U]!  
a^X% (@Sg  
Nv=%R  
byte[] b = new byte[1024]; y 1Wb/ d  
int nRead; \q^ dhY>)  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 4(Y-TFaf  
{ uKJo5%>  
nStartPos += fileAccessI.write(b,0,nRead); EpCNp FQT<  
//if(nThreadID == 1) $bBUL C  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); CG J_k?h  
} sebuuL.l0<  
jxq89x  
P8 w56  
Utility.log("Thread " + nThreadID + " is over!"); }XRfHQk  
bDownOver = true; ^L\w"`,~  
//nPos = fileAccessI.write (b,0,nRead); up~p_{x)Q  
} 5g'aNkF6>  
catch(Exception e){e.printStackTrace ();}  (tT%rj!  
} w*(1qUF#%  
} ,wHlU-%  
=BV_ ?  
0&Iu+hv  
//打印回应的头信息 ~X'hRNFx~  
public void logResponseHead(HttpURLConnection con) })q8{Qj!  
{ NID2$p  
for(int i=1;;i++) O-~cj7 0\  
{ MRK3Cey}%  
String header=con.getHeaderFieldKey(i); OKj\>3  
if(header!=null) *Ct ^jU7  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); P`_Q-vu  
Utility.log(header+" : "+con.getHeaderField(header)); a +9_sUq  
else \!0~$?_)P  
break; 3cNr~`7  
} Y]B9*^d<  
} q'Y)Y(d  
u=#_8e(9Z  
Cs,t:ajP  
public void splitterStop() ,ob)6P^rw  
{ Q%V530 P;  
bStop = true; u2U+uD@yA  
} wNh\pWA  
]*{tno  
'X_%m~}N  
} \@^` G  
^~bAixH^k  
H4M`^r@)'  
/* 4]%MrSjS  
**FileAccess.java `{}DLaD9  
*//文件访问(定位,写) "M %WV>  
package NetFox; ! ;Ctz'wz  
import java.io.*; E-?JHJloU  
>bO}sx1?  
V r T0S  
public class FileAccessI implements Serializable{ 'm/`= QX  
RNcnE1=  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 f4|ir3oy  
RandomAccessFile oSavedFile; }|c-i.0=  
long nPos; 7|)K!  
C}:_&^DQ  
yoBR'$-=  
public FileAccessI() throws IOException Uo|T6N  
{ NnY+=#j7L  
this("",0); _o>?\:A  
} T{F 'Y%  
sB'~=1m^  
d! _8+~  
public FileAccessI(String sName,long nPos) throws IOException Cg^1(dBd[9  
{ dQNW1-s  
oSavedFile = new RandomAccessFile(sName,"rw"); 1%N[DA^<\  
this.nPos = nPos; Y1{*AV6ev6  
oSavedFile.seek(nPos); eTY(~J#'  
} ] ; B`'Ia  
M-C>I;a  
#ePtfRzJ  
public synchronized int write(byte[] b,int nStart,int nLen) A_5M\iN\  
{ ]Lm?3$u$  
int n = -1; ( D@ U%  
try{ Qf}}/k|)k  
oSavedFile.write(b,nStart,nLen); TM,Fab &  
n = nLen; g6.Tx]?b$  
} (.g?|c  
catch(IOException e) OX{2@+f#  
{ FyllVrK  
e.printStackTrace (); }eLth0d`'o  
} 73+)> "x>  
r}#,@<  
qu/b:P  
return n; 8fb<hq<  
} a0&R! E;  
b5^-q c6X  
;k,#o!>  
} IvB)d}p  
5VE9DTE  
A_|X54}w&  
/* Twk,R. O  
**SiteInfoBean.java \U HI%1^  
*/ xG,L*3c{o  
package NetFox; tI+P&L"  
I@I-QiI  
-1]8f  
public class SiteInfoBean { U#(#U0s*-  
%I%OHs  
\7 *"M y*  
private String sSiteURL; //Site's URL qW9~S0sl  
private String sFilePath; //Saved File's Path *<ww~^a  
private String sFileName; //Saved File's Name ?&@a{-  
private int nSplitter; //Count of Splited Downloading File '2S?4Z  
>s>{+6e  
Uc]sWcR  
public SiteInfoBean() `& ]H`KNa  
{//nSplitter的缺省值为5 OUtMel_  
//default value of nSplitter is 5 &MP +  
this("","","",5); w(!COu  
} Uk0 0lPG.U  
sN@=Ri?\  
kaNK@a=e|/  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) R9^R G-x  
{ s.>;(RiJd  
sSiteURL= sURL; `SG8w_  
sFilePath = sPath; ::p(ViYG  
sFileName = sName; )'axJ  
this.nSplitter = nSpiltter; L9,O,f  
k6^!G"  
eq7>-Dmi@  
} jmn<gJ2Of  
#;s5=aH  
q#P@,|nc:  
public String getSSiteURL() H.!\j&4j  
{ Bx ru7E"  
return sSiteURL; Cg];UB}k  
} nT/Az g  
xt X`3=s  
yMKVF`D*  
public void setSSiteURL(String value) t@3y9U$  
{ OEXa^M4x   
sSiteURL = value; fH ?s~X]  
}  [?moS!  
Kb*X2#;*  
A%% Vyz  
public String getSFilePath() ac#I $V-  
{ VK^m]??s_  
return sFilePath; ?m:,hI  
} 75*q^ui  
# 4;(^`?  
9=p/'d8  
public void setSFilePath(String value) .%x%(olf  
{ V-w{~  
sFilePath = value; Y]: Ch (Q  
} |&AZ95v   
9"b  =W@  
9{XV=a v  
public String getSFileName() pij%u<  
{ O <"\G!y~  
return sFileName; N:&EFfg3  
} >\ x!a:}  
+L|-W9"@3  
%p8#pt\$7  
public void setSFileName(String value) w)xfP^M#  
{ oS#PBql4  
sFileName = value; noQS bI @  
} 4ZrRgx2MD  
P,={ C6*  
V D.T=(  
public int getNSplitter() fW3NH7aUG  
{ >A ?,[p`<  
return nSplitter; )^LiAL h  
} I9O%/^5^[w  
T1g3`7C3  
lka Wwjv_D  
public void setNSplitter(int nCount) cX4I+Mf  
{ )6:1`&6  
nSplitter = nCount; wlw`%z-B2  
} yp"h$  
} _j}jh[M  
7'idjcR  
%>!$ eCX  
/* 1Y(NxC0P=g  
**Utility.java 4)NbQ[  
*/ Vl%UT@D|  
package NetFox; \,-e>  
DW0N}>Gp*  
\<W/Z.}/  
public class Utility { 5LJ0V  
]jgMN7  
BY`vs+]XY  
public Utility() MWJ}  
{ Tga%-xr+  
n'qWS/0U=  
);=0cnr3  
} .njk^,N  
-SUK [<=X  
//线程睡眠 a9g~(#?a  
public static void sleep(int nSecond) ;2[o>73F  
{ 0t2n7Y?N  
try{ =;~*YD(%/  
Thread.sleep(nSecond); sny$[!)  
} U%rq(`;  
catch(Exception e) H_FT%`iM  
{ ob]j1gYb  
e.printStackTrace (); UM:]Qba In  
} j] J-#J  
} ,C0D|q4/!.  
tui5?\  
//日志 Hd57Iw  
public static void log(String sMsg) L'u*WHj|v  
{ <HH\VG\H6  
System.err.println(sMsg); #T++5G  
} K8RV=3MBLD  
l- $5CO  
U<I]_]  
public static void log(int sMsg) _f"KB=A_x  
{ rVZlv3  
System.err.println(sMsg); tP4z#0r2  
} 9xaieR  
} sQBKzvFO3  
Q PrP3DK  
I+W:}}"j  
/* k|`Qk!tr  
**TestMethod.java eL88lV]I  
*/ cy0j>-z  
package NetFox; !3`X Gg  
jx14/E+^  
qi$nG_<<Z  
public class TestMethod { %>Mcme>(W  
%\T#Ik~3  
m\G45%m  
public TestMethod() *R3^:Y&  
{ ///xx/weblogic60b2_win.exe <b-OdOg  
try{ [xo-ZDIoG  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); _o? I=UN2:  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); `t3w|%La}  
SiteFileFetch fileFetch = new SiteFileFetch(bean); LjCUkbzQF  
fileFetch.start(); rqz48~\lJ  
} Nr?CZFN#  
catch(Exception e){e.printStackTrace ();} +<bvh<]Od  
^Q9K]Vo  
KzQuLD(e  
} = OzpI  
QY c/f"9  
z&yVU<;  
public static void main(String[] args) Mh]4K" cs  
{ j937tn!Q  
new TestMethod(); BAojP1}+,  
} ;:/C.%d  
} zMh`Uqid  
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