http断点续传简单实现（java)

/* 'VDWJTia  
**SiteFileFetch.java =sJ?]U  
*/ kiTC)S=])  
package NetFox; ?nU<cxh  
import java.io.*; 7^L  
import java.net.*; ).~ "  
N/4E ~^2  
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public class SiteFileFetch extends Thread { V9c.(QY|f  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 2t= =<x  
long[] nStartPos; //开始位置 Ge^`f<f  
long[] nEndPos; //结束位置 H 4<"+7  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 @N*|w Kc+  
long nFileLength; //文件长度 TnrBHaxbo4  
boolean bFirst = true; //是否第一次取文件 ;mQj2Bwr  
boolean bStop = false; //停止标志 #]` uH{  
File tmpFile; //文件下载的临时信息 fBSa8D3}`  
DataOutputStream output; //输出到文件的输出流  a"Qf  
@]3\*&R}  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） XwH>F7HPe  
public SiteFileFetch(SiteInfoBean bean) throws IOException dC=[o\  
{ t7=D$ua  
siteInfoBean = bean; \Kl20?  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); DiJLWXs  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); N J3;[qJ  
if(tmpFile.exists ()) VotC YJ  
{ JEjxY&  
bFirst = false; \!u<)kkyT  
read_nPos(); Lqgrt]L_"  
} -TUJ"ep]QJ  
else 6VW*8~~Xy  
{ ZW4
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nStartPos = new long[bean.getNSplitter()]; XKp&GE@Y  
nEndPos = new long[bean.getNSplitter()]; 8^7Oc,:~  
} ug3\K83aj/  
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} e@D_0OZ  
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public void run() MN?aPpr>  
{ uwwR$ (\7  
//获得文件长度 [F-R*}&x  
//分割文件 xyL"U*  
//实例FileSplitterFetch Z.VKG1e}  
//启动FileSplitterFetch线程 tv#oEM9esl  
//等待子线程返回 d |17G  
try{ yw1&I^7  
if(bFirst) ^rWg:fb  
{ atL<mhRz  
nFileLength = getFileSize(); BP/nK.  
if(nFileLength == -1) p2vN=[g9)  
{ &Ok1j0~~  
System.err.println("File Length is not known!"); #a
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} qC`}vr|Z  
else if(nFileLength == -2) C- .;m  
{ s.J4&2Q  
System.err.println("File is not access!"); c^}y9% 4c  
} 80lei  
else '*J+mZtN  
{ BJ|l  
for(int i=0;i<nStartPos.length;i++) fU>l:BzJK  
{ &@iOB #H  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); nFnM9 pdMK  
} ;;0'BdsL`  
for(int i=0;i<nEndPos.length-1;i++) |UTajEL  
{ {npm9w<;  
nEndPos = nStartPos[i+1]; :=Olp;+_  
} *,\v|]fc  
nEndPos[nEndPos.length-1] = nFileLength; IO)B3,g  
} 9q'9i9/3d  
} 10SI&O  
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8dE0y
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//启动子线程 qTJhYxm  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; (&}[2pb!  
for(int i=0;i<nStartPos.length;i++) )Q2IYCj{  
{ gN/<g8  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), C;W@OS-;  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), OBi(]l}^O  
nStartPos,nEndPos,i); YR?Y:?(  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); T$;S  
fileSplitterFetch.start(); ';C'9k<P:  
} 25>R^2,LiE  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), * %D_\0;  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); n`,  <g  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", )vW'g3u_  
nEndPos = " + nFileLength); *Fy6-
CC1  
// fileSplitterFetch[nPos.length-1].start(); "Zp&7hI  
z\ZnxZ@  
\.LjA_  
//等待子线程结束 u)oAQ<w  
//int count = 0; ~ZKJ:&f  
//是否结束while循环 eF+F"|1h  
boolean breakWhile = false; 'f( CN3.!  
X1#Ar)  
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while(!bStop) w;'XqpP$*|  
{ pGs?Y81  
write_nPos(); ciS +.%7  
Utility.sleep(500); $nt&'Xnv  
breakWhile = true; {irc0gI  
0'o[2,  
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for(int i=0;i<nStartPos.length;i++) ZJDV'mC}  
{ q`xc h[H  
if(!fileSplitterFetch.bDownOver) qo[[P)tq  
{ ^4`aONydl  
breakWhile = false; 0qS/>u*  
break; Wga2).j6  
} x,gk]
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} p:08q B|uQ  
if(breakWhile) ?%,LZw^[  
break; T5:Q_o]  
|Y3w6!$  
XvI~"}  
//count++; 9pLe8D  
//if(count>4) x Lan1V  
// siteStop(); ]0UYxv%]  
}
$@PruY3[  
;\K]~  
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System.err.println("文件下载结束！"); ~4fE`-O  
} mG[jR*JW  
catch(Exception e){e.printStackTrace ();} 6 byeO&d  
} bdL= ?KS  
VhO+nvd*W  
^yW['H6V  
//获得文件长度 d6n_Hpxw^  
public long getFileSize() xJ>5 ol  
{ /EjXyrn2  
int nFileLength = -1; coXg]bUKo  
try{ ?t'V5$k\  
URL url = new URL(siteInfoBean.getSSiteURL()); Im6gWDdq@6  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); v0C+DKi  
httpConnection.setRequestProperty("User-Agent","NetFox"); |]G%b[
 

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}u8(7  
int responseCode=httpConnection.getResponseCode(); ,5W7a  
if(responseCode>=400) 8?Rp2n*o  
{ y8YsS4E^Q  
processErrorCode(responseCode); "^&H9.z,v  
return -2; //-2 represent access is error _d 6'f8[&  
} f1vD{M;  
}+@!c%TCx~  
l8G1N[  
String sHeader; ?^U?ua6  
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0/v]YK.  
for(int i=1;;i++) Z5t^D|  
{ _y4O2n[e  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); F0!Z1S0g  
//Utility.log(in.readLine()); 9"#C%~=+  
sHeader=httpConnection.getHeaderFieldKey(i); v~>Bbe  
if(sHeader!=null) k2 Ju*W&  
{ UF-&L:s[  
if(sHeader.equals("Content-Length")) ^B
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{ Lg<h54X  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); #scZP  
break; 4aArxJ  
} @ki|#ro  
} '~Y@HRVL@|  
else _:[@zxT<x  
break; xt|^~~ /  
} ,lH }Ba02F  
} wN.
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catch(IOException e){e.printStackTrace ();} q8P&rMwy  
catch(Exception e){e.printStackTrace ();} x$q}lJv_  
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9)wYSz'  
Utility.log(nFileLength); # Wi?I=,  
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return nFileLength; #@oB2%&X?  
} VpJKH\)Rt(  
b
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lk>\6o:
 
//保存下载信息（文件指针位置） i D9 */  
private void write_nPos() GQYR`;>  
{ h^g0|p5  
try{ j&X&&=   
output = new DataOutputStream(new FileOutputStream(tmpFile)); ^=eC1bQA  
output.writeInt(nStartPos.length); u)<]Pb})r  
for(int i=0;i<nStartPos.length;i++) D% jGK  
{ L2>e@p\
>  
// output.writeLong(nPos); |Y K,&  
output.writeLong(fileSplitterFetch.nStartPos); &{e ]S!D  
output.writeLong(fileSplitterFetch.nEndPos); ulxlh8=  
} U;W9`JT<.f  
output.close(); nF'YG+;|@  
} P!]uJ8bi  
catch(IOException e){e.printStackTrace ();} ,]EhDW6  
catch(Exception e){e.printStackTrace ();} F`7v  
} g `s|]VNt  
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//读取保存的下载信息（文件指针位置） >e {1e  
private void read_nPos() q;,lv3I  
{ aVu!Qk=Z/  
try{ SE\?8cs]-  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); d3:GmB .  
int nCount = input.readInt(); ,!_6X9N-h  
nStartPos = new long[nCount]; #][i!9$  
nEndPos = new long[nCount]; '4uu@?!dVk  
for(int i=0;i<nStartPos.length;i++) i2Wvu3,D3-  
{ c*rH^Nz  
nStartPos = input.readLong(); di/QJrw  
nEndPos = input.readLong(); &jqylX  
} PcC@}3  
input.close(); R ABw(b  
} Tc(=J7*r&  
catch(IOException e){e.printStackTrace ();} Dizz?O  
catch(Exception e){e.printStackTrace ();} nh4G;qdU  
} 7_\F$bp`  
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kBZ1)?  
private void processErrorCode(int nErrorCode) Q3WI@4  
{ zjA]Tr  
System.err.println("Error Code : " + nErrorCode); by<@\n2B:U  
} ir<e^a  
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//停止文件下载 Wu 0:X*>}p  
public void siteStop() _Gq6xv\b1  
{ &B&8$X  
bStop = true; !hq2AY&H)  
for(int i=0;i<nStartPos.length;i++) 7(1`,Y  
fileSplitterFetch.splitterStop();
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} > T*`Y0P  
} @[lMh9`  
//负责部分文件的抓取 Bh&pZcm|  
**FileSplitterFetch.java dCi:@+z8  
*/ dJgLS^1E  
package NetFox; ;~<To9O  
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b;b,t0wS  
import java.io.*; >g<YH'U{  
import java.net.*; *:yG)J 3F  
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|  
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public class FileSplitterFetch extends Thread { ?)1Y|W'Rv  
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String sURL; //File URL UiG/Rn  
long nStartPos; //File Snippet Start Position ZMQ=D!kT  
long nEndPos; //File Snippet End Position r>fGj\#R =  
int nThreadID; //Thread's ID {]+t<  
boolean bDownOver = false; //Downing is over c9nR&m8(+  
boolean bStop = false; //Stop identical T`!R ki%~  
FileAccessI fileAccessI = null; //File Access interface Ef#LRcG-Z  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException j4owo#OB-  
{
,*iA38d.!  
this.sURL = sURL; bqE'9GI  
this.nStartPos = nStart; }>hn  
this.nEndPos = nEnd; nq{/fD(2  
nThreadID = id; dO82T3T  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 LJ[zF~4#  
} B)Y[~4o  
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public void run() %(6IaqJ[  
{ 2'@m'4-N  
while(nStartPos < nEndPos && !bStop) 96^aI1:  
{ $
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try{ w~u{"E$  
URL url = new URL(sURL); 8Nzn%0(Q  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); $Er=i }`  
httpConnection.setRequestProperty("User-Agent","NetFox"); 'V7LL1K^>  
String sProperty = "bytes="+nStartPos+"-"; w!"L\QT  
httpConnection.setRequestProperty("RANGE",sProperty); C{bxPILw  
Utility.log(sProperty); &DMC\R*j  
S=k!8]/d|  
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InputStream input = httpConnection.getInputStream(); +fk*c[FG  
//logResponseHead(httpConnection); 7z$Z=cs  
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byte[] b = new byte[1024]; x/O;8^b  
int nRead; SxYz)aF~  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) i]c{(gd`  
{ W p)!G  
nStartPos += fileAccessI.write(b,0,nRead); '
oIE:#b  
//if(nThreadID == 1) 4

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// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); bX$z)]KKu  
} WRD z*Zf  
{c*$i^T  
r)|~Rs!y,  
Utility.log("Thread " + nThreadID + " is over!"); LWM<[8wJ4  
bDownOver = true; ya&=UoI  
//nPos = fileAccessI.write (b,0,nRead); WkuCnT  
} %k#+nad  
catch(Exception e){e.printStackTrace ();} b23A&1X  
} n0=]C%wr  
} &|XgWZS5  
ATkd#k%S  
nG'Yo8
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//打印回应的头信息 B!Wp=9)G  
public void logResponseHead(HttpURLConnection con) X)!XR/?  
{ r^ Dm|^f#  
for(int i=1;;i++) CC=I|/mBM  
{ >\1twd{u]  
String header=con.getHeaderFieldKey(i); L"'=[O~  
if(header!=null) -4x! #|]  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); &`qYe)1Eo  
Utility.log(header+" : "+con.getHeaderField(header)); TAUl{??,  
else 4+hNP'e  
break; g!~SHW)l  
} - jZA
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} =Q9^|&
6  
&^$@LH3  
PaSwfjOnqr  
public void splitterStop() MQP9^+f)O?  
{ {>hxmn   
bStop = true; 4dbX!0u1l  
} ,?yjsJd.  
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 b*Qd9  
} IIAp-Y~B  
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\NNA"  
/* eA1g}ipm  
**FileAccess.java ~S('\h)1  
*//文件访问(定位，写) ^Z)7Z% O  
package NetFox; _9=87u0  
import java.io.*; `e ZDG  
~a_hOKU5  
Y)k"KRW+  
public class FileAccessI implements Serializable{ Ze%S<xT!O  
K ar!  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 9C \}bT  
RandomAccessFile oSavedFile; ]lA}5  
long nPos; 2@MpWj4  
rS>.!DiYr,  
1#N`elm  
public FileAccessI() throws IOException 7D<Aa?cv_l  
{ "=Z=SJ1D  
this("",0); 3YLK?X8  
} P1
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public FileAccessI(String sName,long nPos) throws IOException 6|p8_[e`  
{ jlb8<xIC]  
oSavedFile = new RandomAccessFile(sName,"rw"); sFZdj0tQ4  
this.nPos = nPos; $@6q5Iz!&  
oSavedFile.seek(nPos); (72%au  
} U)'YR$2<
 
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public synchronized int write(byte[] b,int nStart,int nLen) #!_4ZX  
{ }N9PV/a  
int n = -1; J <z ^C  
try{ )F hbN@3  
oSavedFile.write(b,nStart,nLen); VJ#ys_W  
n = nLen; tfHr'Qy BC  
} ]A[}:E 5}  
catch(IOException e) M+")*Opq  
{ Wg%]  
e.printStackTrace (); +ase>'<N#  
} 8o:h/F  
(;g/
wb:  
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return n; t~qSiHw  
} kDJYEI9j>  
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x(>XM:|  
} jA^yUd-  
N#-%b"(  
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/* L2Cb/!z`c  
**SiteInfoBean.java R}(Rv3>Xx  
*/ uLv  
package NetFox; [.l,#-vp  
Y|mtQE?c  
0;a10b  
public class SiteInfoBean { !JdZ0l  
0Bgj.?l  
a:P+HU:  
private String sSiteURL; //Site's URL %d:cC:`  
private String sFilePath; //Saved File's Path x%)oL:ue  
private String sFileName; //Saved File's Name &iD&C>;pf  
private int nSplitter; //Count of Splited Downloading File 6a9:P@tY  
}cUO+)!Y  
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public SiteInfoBean() w:I!{iX
  
{//nSplitter的缺省值为5 _$
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//default value of nSplitter is 5 iPCn-DoIS  
this("","","",5); 'xuxMav6m  
} w?_'sP{pd  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) "w 4^i!\  
{ LTx,oa:ma  
sSiteURL= sURL; @}^VA9ULK  
sFilePath = sPath; ~d<&OL  
sFileName = sName; tHqa%  
this.nSplitter = nSpiltter; `E;xI v|  
.5SYN-@  
c;KMox/  
} BQ,749^S  
 f^}n#  
4<<eqxI$|  
public String getSSiteURL() Wf?[GO  
{ ?W dY{;&  
return sSiteURL; KWYjN h#*  
} 3it*l-i\  
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public void setSSiteURL(String value) modem6#x'  
{ ',Z]w;D!G
 
sSiteURL = value; Z @DDuVr  
} 5l,Lp'k  
wKcuIc$  
{Gh9(0,B?  
public String getSFilePath() CE (zt  
{ $<VH~Q<  
return sFilePath; _`*G71PS  
} //3fgoly  
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public void setSFilePath(String value) 1uyd+*/(xP  
{ _b)Ie`a.H  
sFilePath = value; hBz>E 4mEv  
} .i;?8?  
DgRn^gL{Q  
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public String getSFileName() mq}uq9<  
{ o=zl{tZV  
return sFileName; wqjR-$c  
} r~|7paX!  
ifl LY7j  
dBM{]@bZ  
public void setSFileName(String value) ^;{uop"DS  
{ Y#P!<Q>}  
sFileName = value; P=P']\`p+  
} ~USyN'5lU7  
`.~*pT*u  
zDm3$P=  
public int getNSplitter() K4RQ{fWpm  
{ 00>knCe6  
return nSplitter; aU.!+e%_  
} EpT^r8I  
8B "^}y\0  
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public void setNSplitter(int nCount) U.Z5;E0:  
{ 0Bkc93  
nSplitter = nCount; 5)rN#_BKj  
} zt  
} V<}chLd,  
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/* M
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**Utility.java ]W`M <hEI  
*/ _$vbb#QXZG  
package NetFox; g&_f%hx?  
X_3hh}=  
oZL# *Z(h  
public class Utility { "ChJR[4@  
lQRtsmZ0  
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public Utility()  zDxJK  
{ y34<B)Wy  
5]kv1nQ  
XQOM6$~,  
} }:s.m8LC5n  
Xe\v6gbD  
//线程睡眠 #Hl?R5  
public static void sleep(int nSecond) qjg Z

 
{ soLmr's  
try{ VHLNJnA  
Thread.sleep(nSecond); Hh&qjf  
} Osy_C<O  
catch(Exception e) JPZH%#E(  
{ # xX  
e.printStackTrace (); @'P
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} `0+-:sXZ6  
} )g^O'e=m  
pUu<0a^  
//日志 B<G,{k  
public static void log(String sMsg) w)R5@ @C*  
{ s._,IW;   
System.err.println(sMsg); g">^#^hBE  
} yKz%-6cpSl  
YPKB4p#  
<1QXZfQ"  
public static void log(int sMsg) ]{t!J^Xn  
{ HRCnjem/v\  
System.err.println(sMsg); * ]D{[hV  
} YB:}Lb  
} I%<pS,p  
niyxZ<Z  
0<f.r~  
/* 00r7trZW^  
**TestMethod.java \W\*'C8q\  
*/ 9pWSvalw9  
package NetFox; *dC&*6Rx  
6y^GMlsI  
{lppv(U  
public class TestMethod { U+["b-c  
m !i`|]m  
eq<!  
public TestMethod() .Ep&O#  
{ ///xx/weblogic60b2_win.exe E},zB*5TH  
try{ ]9W7]$  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 5e?<x>e  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); j^hLn>  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 0fqycGSmU  
fileFetch.start(); 'C>sYSL  
} V&Rwj_Y  
catch(Exception e){e.printStackTrace ();} }iUpBn  
fILvEf4b  
~Jj~W+h  
} Tgbq4xR(  
-]n%+,3L  
y(^\]-fE  
public static void main(String[] args) .t&G^i'n  
{ Zzb?Nbf  
new TestMethod(); bUYjmb2g)  
} ekmWYQ ~  
} u
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