http断点续传简单实现（java)

/* -Q%Pg<Q-#  
**SiteFileFetch.java  gq}c  
*/ IL"N_ux~w~  
package NetFox; H,LJ$ py  
import java.io.*; U~oGg$  
import java.net.*; 0*AXd=)"*  
9{IDw   
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public class SiteFileFetch extends Thread { r,P`$-  
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SiteInfoBean siteInfoBean = null; //文件信息Bean bE3mOml  
long[] nStartPos; //开始位置 gE8>o:6)6:  
long[] nEndPos; //结束位置 Qr?1\H:Lq  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 isFxo,R9r  
long nFileLength; //文件长度 X-psao0tI`  
boolean bFirst = true; //是否第一次取文件 y'O<*~C(X  
boolean bStop = false; //停止标志 1r3} V7  
File tmpFile; //文件下载的临时信息 v
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DataOutputStream output; //输出到文件的输出流 Xu|2@?l9  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） h]j>S  
public SiteFileFetch(SiteInfoBean bean) throws IOException ;f} ']2  
{ pfFHuS~  
siteInfoBean = bean; |ZOdfr4uW  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ;f)AM}~^Q  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); (,cG+3r]  
if(tmpFile.exists ()) C3(h j  
{ aF>&X-2  
bFirst = false; 9VSi2p*  
read_nPos(); q*cEosi'F?  
} g~76c.u-  
else j@{dsS:6  
{ .-Dc%ap
]  
nStartPos = new long[bean.getNSplitter()]; al7D3J  
nEndPos = new long[bean.getNSplitter()]; $ k_6  
} @\W-=YKLg  
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} "|V}[
2  
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public void run() 5gb:,+  
{  "+Sq}WR  
//获得文件长度 )c532 y  
//分割文件 |f(*R_R  
//实例FileSplitterFetch u^W!$OfZpp  
//启动FileSplitterFetch线程 ]0W64cuT  
//等待子线程返回 3jHg9M23[^  
try{ Q2F20b  
if(bFirst) ;WhRDmT  
{ Oz)/KZ  
nFileLength = getFileSize(); _CBMU'V  
if(nFileLength == -1) d ,.=9
  
{ Z$zX%w  
System.err.println("File Length is not known!"); 4vCUVo r  
} aX Ie  
else if(nFileLength == -2) [6Sk>j  
{ hFxT@I~  
System.err.println("File is not access!"); <2~DI0pp(  
} ln8es{q  
else 9~jS_Y)"  
{ 7xYz9r)w`  
for(int i=0;i<nStartPos.length;i++) zS h9`F  
{ ]'$:Y  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); .L]5,#2([  
} +wQ}ZP&  
for(int i=0;i<nEndPos.length-1;i++) hMUUnr"8;i  
{ k4E9=y?  
nEndPos = nStartPos[i+1]; 5fYWuc9}z  
} gyhy0  
nEndPos[nEndPos.length-1] = nFileLength; dczSW]%  
} ]Tg@wMgI  
} 2 )3oX  
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,+I]\ZeO  
//启动子线程 %s^1de  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; G;EJ\J6@Yw  
for(int i=0;i<nStartPos.length;i++) 23 #JmR  
{ t*H|*L#YR  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), -Q&@P3
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), S4-jFD)U  
nStartPos,nEndPos,i); t)rPXvx}!  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 0WYu5|  
fileSplitterFetch.start(); '2|P-/jU  
} Mc!LC .8  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), (U_HX2f  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1);  yK$aVK"  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", b#R$P]dr=  
nEndPos = " + nFileLength); pS}IU{#;  
// fileSplitterFetch[nPos.length-1].start(); ~tZB1+%)  
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//等待子线程结束 leI ]zDk=  
//int count = 0; %~8f0B|im  
//是否结束while循环 S?J(VJqE  
boolean breakWhile = false; `"<hO 'WU  
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`AvK=]  
while(!bStop) 99CK [G  
{ sLXM$SMBh  
write_nPos(); Fw t  
Utility.sleep(500); c\&;
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breakWhile = true; \sfc!5G  
'>n&3`r5  
hw*u.46  
for(int i=0;i<nStartPos.length;i++) [Q J  
{ zufsmY4P  
if(!fileSplitterFetch.bDownOver) _VTpfeL@n  
{ *[*q#b$j  
breakWhile = false; K<`W>2"  
break; c_?^:xs:d  
} ;[[6[i  
} 78~/1-  
if(breakWhile) jZ:/d
!
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break; 11kyrv  
cMnN} '  
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//count++; !$>b}w'  
//if(count>4) 9!Jt}n?!g  
// siteStop(); PHY!yc-LjV  
} 4;r,U{uR  
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System.err.println("文件下载结束！"); z8]@Gh+ (  
} cAot+N+9|]  
catch(Exception e){e.printStackTrace ();} 0a#v}w^*  
} udIm}jRA"  
-.ZP<,?@F  
\i@R5v=zL  
//获得文件长度 .:B>xg~2  
public long getFileSize() );6f8H@G  
{ ?%Tx% dB  
int nFileLength = -1; MPy><J  
try{ `Syfl^9B  
URL url = new URL(siteInfoBean.getSSiteURL()); 4z26a  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); a?8)47)  
httpConnection.setRequestProperty("User-Agent","NetFox"); BHYguS^qz  
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int responseCode=httpConnection.getResponseCode(); (v|<" tv  
if(responseCode>=400) \_6  
{ 75R#gQ]EV  
processErrorCode(responseCode); !MOsP<2  
return -2; //-2 represent access is error zUZET'Bm9  
} Xw<;)m  
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String sHeader; A9u>bWIE7  
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for(int i=1;;i++) W*#5Sk  
{ -C}"1|P!  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ?A_+G 5  
//Utility.log(in.readLine()); JX[]u<h?  
sHeader=httpConnection.getHeaderFieldKey(i); (xVx|:R[<H  
if(sHeader!=null) <eS/-W%n6  
{ e*PUs  
if(sHeader.equals("Content-Length")) $Cfp1#  
{ JMo 
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nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); (w5cp!qW9J  
break; %N&W_.F6  
} ID!S}D  
} <)T~_s  
else _@[W[=|H  
break; 6 R})KIG  
} J5HK1  
} !6RDq`  
catch(IOException e){e.printStackTrace ();} 3&AJN#c  
catch(Exception e){e.printStackTrace ();} Ba|}$jo  
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Utility.log(nFileLength); ,+6u6  
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return nFileLength; Hi
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} ~9vK6;0  
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TNA7(<"fV|  
//保存下载信息（文件指针位置） qm:C1#<p   
private void write_nPos() ~D4l64  
{ j4=iHnE;  
try{ `67i1w`  
output = new DataOutputStream(new FileOutputStream(tmpFile)); {z0iWY2Xw  
output.writeInt(nStartPos.length); Ng*-Bw)p]  
for(int i=0;i<nStartPos.length;i++) LD5`9-  
{ {"{]S12N  
// output.writeLong(nPos); j3/6hE
>  
output.writeLong(fileSplitterFetch.nStartPos); REK):(i7P  
output.writeLong(fileSplitterFetch.nEndPos); :DNI\TmhJ  
} 2y;vX|lX]  
output.close(); ~&qvS  
} su1fsoL0  
catch(IOException e){e.printStackTrace ();} Dv/7w[F  
catch(Exception e){e.printStackTrace ();} h4|}BGO  
} <,n:w[+!`P  
4m91XD  
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//读取保存的下载信息（文件指针位置） FjtS  
private void read_nPos() k_wcol,W  
{ x< 2]UB`  
try{ 6Q]c}  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Z@&%"nO  
int nCount = input.readInt(); tUc<ExvP,  
nStartPos = new long[nCount]; M."/"hV`-  
nEndPos = new long[nCount]; ([>__c/Nd  
for(int i=0;i<nStartPos.length;i++) J9*;Bqzim  
{ 7_l Wr  
nStartPos = input.readLong(); uyB2   
nEndPos = input.readLong(); TaHcvjhR  
} LDHu10l  
input.close(); \ f+;X  
} 5=|h~/.k  
catch(IOException e){e.printStackTrace ();} 7I"~a<f0X`  
catch(Exception e){e.printStackTrace ();} 5o>`7(t`  
} rM A%By^L-  
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~//E'V-  
private void processErrorCode(int nErrorCode) wLqj<ot  
{ Qr3!6  
System.err.println("Error Code : " + nErrorCode); _",(!(  
} L@6]~[JvP  
KhB775  
eUB!sR%  
//停止文件下载 "49dsKIOH  
public void siteStop() *Ic^9njt  
{ UhS:tT]7  
bStop = true; $o5i15Oy.  
for(int i=0;i<nStartPos.length;i++) l:UKU!  
fileSplitterFetch.splitterStop(); m+s*Io{Ip  
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} wyB]!4yy,  
} * BR#^Wt  
//负责部分文件的抓取 %~Rg`+  
**FileSplitterFetch.java FP=- jf/  
*/ Er j{_i?R?  
package NetFox; Y]0
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import java.io.*; 59l9_yFJ  
import java.net.*; v:/!OvLe  
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2!B|w8ar  
public class FileSplitterFetch extends Thread { _1G/qHf^S  
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>(igVaZ>  
String sURL; //File URL S 4 17.n  
long nStartPos; //File Snippet Start Position U~7udUR  
long nEndPos; //File Snippet End Position V^[&4  
int nThreadID; //Thread's ID (W:@v&p  
boolean bDownOver = false; //Downing is over $RYGAh  
boolean bStop = false; //Stop identical }l$zZ>.\H  
FileAccessI fileAccessI = null; //File Access interface r.#r!.6 q  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException U-1UWq  
{ !fn%Q'S  
this.sURL = sURL; H<i!C|AF  
this.nStartPos = nStart; E:**gvfq  
this.nEndPos = nEnd; 8o%Vn'^t  
nThreadID = id; {X(nn.GpC  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 @#,/6s7?  
} FD 8Lk  
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public void run() #9]2Uixq[  
{ zc)nDyn  
while(nStartPos < nEndPos && !bStop) _p0Yhju?  
{ Ev
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try{ eu$VKLY*  
URL url = new URL(sURL); 9 CZ@IFS  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); _^GBfM.  
httpConnection.setRequestProperty("User-Agent","NetFox"); MjC<N[WO>N  
String sProperty = "bytes="+nStartPos+"-"; TCyev[(  
httpConnection.setRequestProperty("RANGE",sProperty); o<!H/PN  
Utility.log(sProperty); T2w4D!  
ZOV,yuD{8{  
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InputStream input = httpConnection.getInputStream(); [}HPV+j=U  
//logResponseHead(httpConnection); wQy~5+LE  
,%IP27bPW  
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byte[] b = new byte[1024]; T]&?^QGAZ  
int nRead; 8
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while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) E<3xv;v8r  
{ `0]N#G T  
nStartPos += fileAccessI.write(b,0,nRead); GZrN,M  
//if(nThreadID == 1) hfY/)-60o  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Fn`Zw:vp6  
} h]&  
5O]tkHYR  
p )JR5z  
Utility.log("Thread " + nThreadID + " is over!"); |Sjy   
bDownOver = true; !% W5@tN  
//nPos = fileAccessI.write (b,0,nRead); F6yFKNK!n  
} pIK:$eN!/  
catch(Exception e){e.printStackTrace ();} fG>3gS6&  
} 1DcBF@3sWG  
} Q}B]b-c+E  
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-avxH?;?
7  
//打印回应的头信息 >e6OlIW  
public void logResponseHead(HttpURLConnection con) ]h`*w  
{ 18F}3t??  
for(int i=1;;i++) q9ra  
{ 5"57F88Y1  
String header=con.getHeaderFieldKey(i); +5|k#'%5  
if(header!=null) PV~D;  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); cb)7$S  
Utility.log(header+" : "+con.getHeaderField(header)); ,iao56`
E  
else |-S!)iG1V  
break; *> nOL  
} bskoi;)u  
} p#P<V%  

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public void splitterStop() LhAW|];  
{ 3h.,7,T  
bStop = true; eJ45:]_%I@  
} N(4y}-w$  

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} 3;Yd"  
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/* HJg&fkHn1  
**FileAccess.java |^5"-3Q  
*//文件访问(定位，写) F5x*#/af  
package NetFox; (kY0<  
import java.io.*; S"G(_%  
uQ_C<ii"W  
7$%G3Q|)L  
public class FileAccessI implements Serializable{ $dI mA  
&UnhYG{A  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 CQ6I4k  
RandomAccessFile oSavedFile; H0"'jd  
long nPos; J'ce?_\?PY  
(SW6?5  
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public FileAccessI() throws IOException Gu$J;bXVj  
{ e6_8f*o|s  
this("",0); &':C"_|&r  
} cd1-2-4U  
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public FileAccessI(String sName,long nPos) throws IOException ]3,9."^  
{ {~9HJDcM  
oSavedFile = new RandomAccessFile(sName,"rw"); e{87n>+,  
this.nPos = nPos; n;:.UGl9.  
oSavedFile.seek(nPos); .+XK>jl+  
} 3]kM&lK5\  
7P(o!%H  
oS%(~])\  
public synchronized int write(byte[] b,int nStart,int nLen) ldp9+7n~  
{ y[l{ UBue:  
int n = -1; I>nYI|o1  
try{ Ek `bPQ5  
oSavedFile.write(b,nStart,nLen); .GJbrz  
n = nLen; ly34aD/p~,  
} q 6UZ`9&z  
catch(IOException e) lbt8S.fx  
{ D1-w>Y#  
e.printStackTrace (); M/.M~/~  
} /dg?6XT/  
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j~\FDcG*ed  
return n; H?;+C/-K`_  
} dpS@:  
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tx[;& ;  
} _I;hM  
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) q'D9x9  
/* '+$r7?dKP  
**SiteInfoBean.java f@ |[pT  
*/ U3B&3K} ~  
package NetFox; X1P1 $RdkR  
r1IvA^X  
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public class SiteInfoBean { Ji,;ri2
i  
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private String sSiteURL; //Site's URL |*J;X<Vm  
private String sFilePath; //Saved File's Path GjW(&p$&  
private String sFileName; //Saved File's Name <`Fl I
go  
private int nSplitter; //Count of Splited Downloading File S6bYd`  
<HJLs+C  
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public SiteInfoBean() 8d'/w}GV  
{//nSplitter的缺省值为5 ) C~#W  
//default value of nSplitter is 5 Rh6CV  
this("","","",5); j8e=],sQ  
} &/^p:I  
sV5k@1Y  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 9.dZA9l@g  
{ a>4q"IT6  
sSiteURL= sURL; UK^w;w2F  
sFilePath = sPath; 1S(oi  
sFileName = sName; .yUD\ZGJu  
this.nSplitter = nSpiltter; J_&cI%.  
7ZAxhFC  
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} %jj-\Gz!  
W^[QEmyn  
!X"nN9k  
public String getSSiteURL() aDz% %%:r  
{ +ah4 K(+3  
return sSiteURL; 3C=QWw?  
} dMjQV&  
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@~$=96^  
public void setSSiteURL(String value) KMb
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{ ;dZZOocV1  
sSiteURL = value; 7mi=Xa:U  
} .XK3o .ZhW  
?S=y>b9R  
dmkGIg}  
public String getSFilePath() I31Nu{  
{ D?Ol)aj?  
return sFilePath; ?T%"Jgy8  
} 0nI*9  
`3[
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py~[M'p(H  
public void setSFilePath(String value) f9_Pn'"I  
{ A`vRUl,c=  
sFilePath = value; :SN?t  
} OBlQ   
$M-"az]  
*R4=4e2#S  
public String getSFileName() .u7grC C  
{ G^<m0ew|  
return sFileName; 4s>L]! W$8  
} z/5TYv
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*pS3xit~  
%y>*9$<pXe  
public void setSFileName(String value) 'dQGb-<_<  
{ $i8oLSRV  
sFileName = value; It3@ Cd>  
} d\A7}_r*x  
8EiS\$O-  
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public int getNSplitter() VWXyN  
{ gQhYM7NP{5  
return nSplitter; c2GTN"  
} 60|m3|0o  
^N ;TCn  
th"Aatmp  
public void setNSplitter(int nCount) ]B&jMj~y&  
{ bTYR=^9  
nSplitter = nCount; I)3LJK  
} Rdj3dg'<  
} J+Y?'"r  
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/* @1k-h;`,  
**Utility.java ;L],i<F  
*/ 
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package NetFox; y(
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,*L3  
public class Utility { [e|9%[.V  
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A i#~Eu*  
public Utility() #cJ1Jj $  
{ ,4,./wIq  
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} 6_w~#86=  
,k:>Z&:  
//线程睡眠 oC!z
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public static void sleep(int nSecond) gazX2P[D  
{ Q`=d5Uvw  
try{ 6%c]{eTd9  
Thread.sleep(nSecond);
?%>S5,f_  
}
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catch(Exception e) d(D|rf,av  
{ JAmpU^(C  
e.printStackTrace (); m$'ZiS5  
} 0}>p)k3&A  
} >bwq  
'_n$xfH  
//日志 0e'@Xo2e  
public static void log(String sMsg) [GW;RjPE  
{ 7X/B9Hee  
System.err.println(sMsg); x)kp*^/  
} YO.+06X  
99Nm?$g  
`qy@Qo  
public static void log(int sMsg) Q,o"[ &Gp  
{ qHYoQ.ke  
System.err.println(sMsg); oHethk  
} ) @f6  
} SUoUXh^!w  
@w,O1Xwj  
&X}i%etp^2  
/* N/B-u
)?\:  
**TestMethod.java gF|u%_y-qt  
*/ QIcc@PGT9a  
package NetFox; V9D>Xh!0H  
=kW7|c5Z  
5q}7#{A  
public class TestMethod { RDu{U(!  
~N+H7T.L  
o7fJ@3B/  
public TestMethod() 0ol*!@?  
{ ///xx/weblogic60b2_win.exe _/}/1/y$Y  
try{ io$fL_R=  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); $viZ[Lu!m  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); yzL6oU-{&  
SiteFileFetch fileFetch = new SiteFileFetch(bean); u5
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fileFetch.start(); f5t/=/6>F  
} y>JSo9[@  
catch(Exception e){e.printStackTrace ();} #<R6!"TNoz  
@aWd0e]  
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} ",45p@  
vSJ# }&  
;c#jO:A5  
public static void main(String[] args) x?G"58  
{ IKeO&]k  
new TestMethod(); f2M}N  
}
6"c(5#H  
} WP?AQD  
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