http断点续传简单实现（java)

/* \ +xIH  
**SiteFileFetch.java zB$6e!fc  
*/ .nH /=  
package NetFox; )IhY&?jk?  
import java.io.*; %UJ4wm  
import java.net.*; #"{8Z&Z  
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public class SiteFileFetch extends Thread { W7o/  
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*n'xS L  
SiteInfoBean siteInfoBean = null; //文件信息Bean qi2dTB  
long[] nStartPos; //开始位置 RGLA}|  
long[] nEndPos; //结束位置 Wd5t,8*8  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 dZgfls  
long nFileLength; //文件长度 x+e _pb   
boolean bFirst = true; //是否第一次取文件 s-V$N  
boolean bStop = false; //停止标志 P[K=']c  
File tmpFile; //文件下载的临时信息 %p60pn[(  
DataOutputStream output; //输出到文件的输出流 k#) .E X  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） z0[ZO1Fo(  
public SiteFileFetch(SiteInfoBean bean) throws IOException b]#d04]  
{ 5,ahKB8  
siteInfoBean = bean; )+,jal^7  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); h,'+w  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); QZox3LM1&.  
if(tmpFile.exists ()) NF!1)  
{ n^02@Aw  
bFirst = false; Z|%2495\  
read_nPos(); zpqNmxmF  
} )>5k'1  
else X2YOD2<v  
{ am+mXb  
nStartPos = new long[bean.getNSplitter()]; |uBC0f  
nEndPos = new long[bean.getNSplitter()]; H`lD@q'S  
} Wb)l8[=  
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} ]UT|BE4v  
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*;E+9^:V  
public void run() T}Vpy`  
{ ?}v%JUcs  
//获得文件长度 n(YHk\2  
//分割文件 0uO=wOIhH  
//实例FileSplitterFetch X/K)kIi  
//启动FileSplitterFetch线程 \Fg6b6  
//等待子线程返回 yPh2P5}H>  
try{ hdJwNmEA>  
if(bFirst) v#]v,C-*  
{ xf"5<PTW</  
nFileLength = getFileSize(); *8.@aX3  
if(nFileLength == -1) !aw#',r8m  
{ 83ic@[  
System.err.println("File Length is not known!"); 6eYf2sZ;J  
} @PoFxv  
else if(nFileLength == -2) AYA&&b  
{ A:bPIXb  
System.err.println("File is not access!"); zB6u-4^wT  
} ?t0zsq  
else ' q<EZ{  
{ H]$=*(aje  
for(int i=0;i<nStartPos.length;i++) Q|= Q]$d  
{ w-H%B`/  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); C7 ]DJn  
} Vx6?@R  
for(int i=0;i<nEndPos.length-1;i++) $rpTs?j*K$  
{ Ly)(_Tp@+  
nEndPos = nStartPos[i+1]; GtM( Y  
} Vv
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nEndPos[nEndPos.length-1] = nFileLength; e@:P2(WWl  
} UhS
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} 5Hwo)S]r  
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//启动子线程 @UpC{M--Wr  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ?H[5O+P[  
for(int i=0;i<nStartPos.length;i++) Q\27\2  
{ X$-boe?  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), C'-zh\a  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), aI={,\  
nStartPos,nEndPos,i); pG!(6V-x<E  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); h eE'S/  
fileSplitterFetch.start(); ;v,9v;T  
} %Ui{=920  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), A \MfF  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); -v;n"Zy1  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", s-C!uq  
nEndPos = " + nFileLength); llHc=&y#  
// fileSplitterFetch[nPos.length-1].start(); kRN|TDx(  
ShWHHU(QQ  
3tT|9Tb@  
//等待子线程结束 TsaW5ho<p  
//int count = 0; 7_Ba3+9jpa  
//是否结束while循环 3:[!t%Yb  
boolean breakWhile = false; =PNdP  
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RDs,sj/Y9?  
while(!bStop) mb0n}I_AC  
{ X0y?<G1(a  
write_nPos(); ^uyNv-'F  
Utility.sleep(500); \npz.g^c_  
breakWhile = true; !}>eo2$r^  
'8)Wd"[  
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for(int i=0;i<nStartPos.length;i++) 29"mE;j  
{ XVQL.A7  
if(!fileSplitterFetch.bDownOver) |EF>Y9   
{ <9ma(PFa  
breakWhile = false; 0TTIaa$  
break; [O=W>l  
} ;"1/#CY773  
} L~*u4  
if(breakWhile) 'sj9[o@]  
break; 3PsxOb+  
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XjX 2[*l  
//count++; }dy9IH  
//if(count>4) ~6p5H}'H1  
// siteStop(); Q"A_bdg5  
} ,# ]+HS^B  
8{oZi]ob  
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System.err.println("文件下载结束！"); 1{^CfamF  
} R;WW f.#  
catch(Exception e){e.printStackTrace ();} PmHd9^C  
} >gr<^$
 
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//获得文件长度 19
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public long getFileSize() 2zhn`m  
{ fTBVvY4(
 
int nFileLength = -1; W;qP=DK2  
try{ nh<Z1tMU  
URL url = new URL(siteInfoBean.getSSiteURL());
}7%9}2}Iw  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); rR\;G2
p)  
httpConnection.setRequestProperty("User-Agent","NetFox"); sa G8g  

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int responseCode=httpConnection.getResponseCode(); vHS2q >  
if(responseCode>=400) .@@an;C  
{ $%=G[/i'  
processErrorCode(responseCode); 7#ofNH J  
return -2; //-2 represent access is error +>!V]S  
} nWk e#{[  
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s"WBw'_<<  
String sHeader; w-ALCh8o
 
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for(int i=1;;i++) Jld\8=  
{ o,1Dqg4P3  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); [X<Pk  
//Utility.log(in.readLine()); q6REh;$  
sHeader=httpConnection.getHeaderFieldKey(i); FIS "Z(  
if(sHeader!=null) LL.x11o3  
{ f0DK>L  
if(sHeader.equals("Content-Length")) vQgq]mA?  
{ &<Zdyf?[Ou  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); FAw1o  
break; Z/g]o#  
} L=]p_2+  
}  m*dNrG  
else /P:EWUf'  
break; w"~<h;  
} DZk1Z
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} m(_9<bc>  
catch(IOException e){e.printStackTrace ();} Vm,,u
F  
catch(Exception e){e.printStackTrace ();} <*wM=aq  
;&S;%W>|  
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Utility.log(nFileLength); X{\jK]O  
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return nFileLength; (%'9CfPx  
} vy9dAl  
`5l01nOxJ  
g`[$XiR  
//保存下载信息（文件指针位置） )];aIA$  
private void write_nPos() e.8$ga{  
{ x)oRSsv!Tr  
try{ "HK/u(z)  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 1m)M;^_  
output.writeInt(nStartPos.length); v* ~3Z1  
for(int i=0;i<nStartPos.length;i++) N'?u1P4G  
{ H M:r0_  
// output.writeLong(nPos); L;/n!k.A  
output.writeLong(fileSplitterFetch.nStartPos); &%,DZA`  
output.writeLong(fileSplitterFetch.nEndPos); .zkP~xQ~  
} Z a(|(M
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output.close(); ;;#`#v  
} -6C +LbV  
catch(IOException e){e.printStackTrace ();} N`$!p9r  
catch(Exception e){e.printStackTrace ();} iqPBsIW  
} ;Gd~YGW^#  
H"Dn]$Q\Z  
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//读取保存的下载信息（文件指针位置） E=w3=\JP  
private void read_nPos() z]@6fM[  
{ :YO@_  
try{ rRb+_]Lg  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); j.|U=)E  
int nCount = input.readInt(); 7o]HQ[xO  
nStartPos = new long[nCount]; 6v732;^  
nEndPos = new long[nCount]; |J>WC}g@n  
for(int i=0;i<nStartPos.length;i++) ^jSsa  
{ `u_Qa  
nStartPos = input.readLong(); .*5Z"Q['G  
nEndPos = input.readLong(); d)ahF[82  
} ] d?x$>  
input.close(); 9pD 7 f`  
} h~}.G{"  
catch(IOException e){e.printStackTrace ();} Z-X?JA\&  
catch(Exception e){e.printStackTrace ();} CIC
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} diT=x52  
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{D`T0qPT[  
private void processErrorCode(int nErrorCode) ajH"Jy3A  
{ } cNW^4F  
System.err.println("Error Code : " + nErrorCode); [\e@_vY@OH  
} n"D ?I  
#JW+~FU`  
nE W31 8  
//停止文件下载 tkKJh !Q7  
public void siteStop() >Aq:K^D/3F  
{ E-2eOT  
bStop = true; A%bCMP  
for(int i=0;i<nStartPos.length;i++) (p)!Mq "^  
fileSplitterFetch.splitterStop(); $j
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3
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} 83Ou9E!W  
} 6g:|*w  
//负责部分文件的抓取 uaPx"  
**FileSplitterFetch.java /
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*/
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package NetFox; ^A_;#vK  
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import java.io.*; r%]Qlt~K  
import java.net.*; :l\V'=%9'@  
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public class FileSplitterFetch extends Thread { ef"?|sn  
sy5 Fn~\R  
qL /7^)(  
String sURL; //File URL 0#p/A^\#7M  
long nStartPos; //File Snippet Start Position _.)eL3OF  
long nEndPos; //File Snippet End Position r?$?;%|C  
int nThreadID; //Thread's ID 5jcte< 5I_  
boolean bDownOver = false; //Downing is over Q /x8 #X  
boolean bStop = false; //Stop identical vIGw6BJI  
FileAccessI fileAccessI = null; //File Access interface B9dt=j3j2  
?\=/$Gt  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException  vb{i  
{ .p` pG3  
this.sURL = sURL; 2h=%K/hhY  
this.nStartPos = nStart; ^ZRYRA  
this.nEndPos = nEnd; eDKxn8+(H  
nThreadID = id; )u:Q) %$t  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 je,}_:7  
} :3h{ A`u  
+~zXDBS9  
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public void run() K,ej%Vtz  
{ : esg(  
while(nStartPos < nEndPos && !bStop)
/7c~nBU  
{ g2cVZ!GIj  
(t^n'V  
PyC0Q\$%  
try{ QbFHfA2Ij  
URL url = new URL(sURL); I,@r5tKo  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); h!@,8y[B  
httpConnection.setRequestProperty("User-Agent","NetFox"); kh$_!BT  
String sProperty = "bytes="+nStartPos+"-"; t0&
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httpConnection.setRequestProperty("RANGE",sProperty); Z3KO90O!8  
Utility.log(sProperty); 8TV;Rtl  
:;;E<74e i  
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InputStream input = httpConnection.getInputStream(); "d/s5sP|S  
//logResponseHead(httpConnection); +!t}  
^?"\?M1  
7
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byte[] b = new byte[1024]; kK>Xrj6  
int nRead; vYmSKS  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) BcWcdr+}9  
{ q(o/yx{bm  
nStartPos += fileAccessI.write(b,0,nRead); G`h+l<  
//if(nThreadID == 1) B/f0P(7  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); zR6siAV9  
} b}9[s  
>cMd\%^t  
t !`Jse>  
Utility.log("Thread " + nThreadID + " is over!"); :t$aN|>y  
bDownOver = true; |
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//nPos = fileAccessI.write (b,0,nRead); gT+Bhr  
} 2RtHg_d_l  
catch(Exception e){e.printStackTrace ();} t G.(flW,  
} jn%kG ~]'Q  
} -cF'2Sfr  
zoDZZ%{  
PaB!,<A  
//打印回应的头信息 SkNre$>t{  
public void logResponseHead(HttpURLConnection con) 1^J`1  
{ 8y';\(;  
for(int i=1;;i++) /?-7Fg+,  
{ u`:
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String header=con.getHeaderFieldKey(i); (P|~>k  
if(header!=null) H4-qB Z'  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); w)]H ^6  
Utility.log(header+" : "+con.getHeaderField(header)); xG&SX#[2  
else \$*$='6"  
break; dj6*6qX0'^  
} <-Bx&Q  
} yR~-k?7b  
1t[j"CG(o  
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public void splitterStop() V:NI4dv/R  
{ -C7]qbT }  
bStop = true; lG<hlYckv  
} 8euZTfK9e  
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7B9`<{!h  
} Rs& @4_D  
^D67y%  
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/* =TvzS%U  
**FileAccess.java ~=r^3nZR/J  
*//文件访问(定位，写) [t]X/O3<  
package NetFox; he3SR@\T  
import java.io.*; v`q\6i[-  
`:{B(+6  
7Ob*Yv=[  
public class FileAccessI implements Serializable{ \6|/RFT  
>ndJNinV  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 LS>G4 ]  
RandomAccessFile oSavedFile; pj|pcv^  
long nPos; ER&UBUu"  
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public FileAccessI() throws IOException ]ekk }0  
{ XhU@W}}  
this("",0); 9$K;Raz%  
} )w~Fo,  
p 5u_1U0  
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public FileAccessI(String sName,long nPos) throws IOException "7%:sty  
{ y9Y1PH7G  
oSavedFile = new RandomAccessFile(sName,"rw");
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this.nPos = nPos; JYqSL)Ta*t  
oSavedFile.seek(nPos); m,LG=s  
} d=.2@Ry  
dmrps+L  
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public synchronized int write(byte[] b,int nStart,int nLen) f}%D"gz  
{ ZBD;a;wx  
int n = -1; iSK+GQ~  
try{
\79X{mcd  
oSavedFile.write(b,nStart,nLen); <M
?:  
n = nLen; 6bc337b  
} k4J8O3E  
catch(IOException e) [ Mg8/Oy  
{ Lr;(xw\[
'  
e.printStackTrace (); `XTh1Z\  
} Cz#Z<:  
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j'%4{n  
return n; 4\t1mocCSN  
} =%)+%[wv  
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} &>WWzikB*  
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.@ C{3$,VG  
/* HY;o^drd  
**SiteInfoBean.java }S-DB#6  
*/ ij5g^{_T;8  
package NetFox; +eX)48
 
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public class SiteInfoBean { l7(!`NPbC  
6~:Sgt nU  
}G46g#_6d>  
private String sSiteURL; //Site's URL c47")2/yO  
private String sFilePath; //Saved File's Path {)f~#37  
private String sFileName; //Saved File's Name
DQ.v+C,  
private int nSplitter; //Count of Splited Downloading File PALl sGlf  
Vpfp}pL  
_?7#MWe&  
public SiteInfoBean() >C WKH~  
{//nSplitter的缺省值为5 `;,Pb&
W~  
//default value of nSplitter is 5 ~H)4)r^  
this("","","",5); nm$Dd~mxW1  
} SQsSa1  
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rRES8/  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) |4)  
{ 1RLY $M  
sSiteURL= sURL; (LvS :?T}  
sFilePath = sPath; MJ<Jb,D1  
sFileName = sName; z><5R|Gf  
this.nSplitter = nSpiltter; &Wp8u#4L  
z@s5m}  
n;HHogA  
} ?q`0ZuAg\<  
~jU/<~s  
80}+MWdo  
public String getSSiteURL() A% Q!^d  
{ {P9J8@D  
return sSiteURL; D\~zS`}  
} {>3\N0e5  
d|9b~_::V  
rjt
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public void setSSiteURL(String value) H?1xjY9sl  
{ _3iHkQr  
sSiteURL = value; l@j.hTO<  
} Uk*IpP`  
aIy*pmpD=  
Mk<Vydds  
public String getSFilePath() dhg~$CVO  
{ h/eR  
return sFilePath; g]@(E  
} Zv]x'3J#Y  
z@|dzvjl Q  
8VG!TpX/B  
public void setSFilePath(String value) :%&Q-kk4!  
{ B3m_D"?  
sFilePath = value; a?} .Fs  
} 8kE]_t  
(GnuWc\p  
A,-6|&F  
public String getSFileName() ?PA$Ur21lw  
{ bUV >^d  
return sFileName; qs\2Z@;  
} _
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@}_WE,r  
+cJy._pi!  
public void setSFileName(String value) 7qOa ;^T  
{ _LP/!D  
sFileName = value; mE O\r|A  
} <H3ezv1M  
\}6;Kf}\  
<99M@ cF  
public int getNSplitter() m42T9wSsx  
{ iUMY!eqp  
return nSplitter; eAUcv`[#p  
} 
:(dHY  
U<"WK"SM  
]A FI\$qB\  
public void setNSplitter(int nCount) )}Q(Tl\$  
{ 4${jr\q]  
nSplitter = nCount; ')a(.f  
} .)1_Ew  
} g&dPd7  
KKA~#iCk  
gh`m*@  
/* G;> _<22  
**Utility.java 6cqP2!~  
*/ ,F&g5'  
package NetFox; %0#1t 5g  
-(#I3h;I  
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public class Utility { nEzf.[+9/  
bo.(zAz  
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public Utility() e\O/H<  
{ 6y%0`!  
.4.b*5  
sNun+xsf^  
} Kn+S,1r  
Zmbfq8K  
//线程睡眠 ^Rm  
public static void sleep(int nSecond) !lo/xQ<  
{ MX@IHc  
try{ TAjh"JJIV  
Thread.sleep(nSecond); fs/*V~@  
} QMv@:Eo  
catch(Exception e) vb9OonE2  
{ hsu{eyp  
e.printStackTrace (); zB yqD$  
} m%?V7-9!k  
} 0!v->Dk  
n~VD uKn9  
//日志 P2Vg4   
public static void log(String sMsg) 0'nikLaKy  
{ \"hJCP?,  
System.err.println(sMsg); V|\7')Qq  
} e%W$*f  
4Qn$9D+?  
$1SUU F\.  
public static void log(int sMsg) "Ks,kSEzu  
{ ON+J>$[[  
System.err.println(sMsg); )>BHL3@  
} 4@xE8`+bG  
} G@j0rnn>B  
[$[:"N_  
F2X0%te  
/* O$4yAaD X  
**TestMethod.java [=~pe|8:  
*/ `p+Zz"/  
package NetFox; ^j7azn  
r&FDEBh  
bJs9X/E  
public class TestMethod { /Z7iLq~t"G  
o=
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5ZBKRu  
public TestMethod() * RtgC/  
{ ///xx/weblogic60b2_win.exe av~5l4YL  
try{ IsR!'%Pu  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); }l=xiAF  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 4
bgqg0z>  
SiteFileFetch fileFetch = new SiteFileFetch(bean); m)oJFF  
fileFetch.start(); 13Lr}M&  
} vx4+QQYP  
catch(Exception e){e.printStackTrace ();} j)q\9#sI/(  
W6Y@U$P#G  

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} #Qkroji qw  
Rn@#d}  
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public static void main(String[] args) 71l%MH  
{ !kC*g  
new TestMethod(); 9+pmS#>_  
} {^N[("`  
} QPq7R  
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