http断点续传简单实现（java)

/* ZfIeq<8_  
**SiteFileFetch.java Dlu]4n[LB  
*/ ou'|e"tI  
package NetFox; ,DWC=:@X  
import java.io.*; .2STBh.;  
import java.net.*; jh.e&6  
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public class SiteFileFetch extends Thread { +jz%:D  
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SiteInfoBean siteInfoBean = null; //文件信息Bean qy~@cPT  
long[] nStartPos; //开始位置 Z~Z+Yt;,9a  
long[] nEndPos; //结束位置 p4{3H+y  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ,V:RE y  
long nFileLength; //文件长度 >d#6qXKAU  
boolean bFirst = true; //是否第一次取文件 ||sj*K  
boolean bStop = false; //停止标志 r=pb7=M#LN  
File tmpFile; //文件下载的临时信息 ]$96#}7N  
DataOutputStream output; //输出到文件的输出流 lIF*$#`oh*  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） }x}JzA+2  
public SiteFileFetch(SiteInfoBean bean) throws IOException mdD9Q N01  
{ -)ag9{*  
siteInfoBean = bean; ) _O
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//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); U?Icyn3q0  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); h^6Yjy  
if(tmpFile.exists ()) =D~RIt/D  
{ hFWK^]~ a  
bFirst = false; #>byP?)n  
read_nPos(); iVGc\6+'  
} k@= LR  
else }D&fw=r"M  
{ 7Y(ySW  
nStartPos = new long[bean.getNSplitter()]; g?caE)  
nEndPos = new long[bean.getNSplitter()]; We*)RXm%  
} -"e$ VB  
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} iy_\1jB0  
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public void run() z~BrKdS  
{ p@7[w@B\c  
//获得文件长度 = A !;`G  
//分割文件 U'acVcD  
//实例FileSplitterFetch #TX=%x6  
//启动FileSplitterFetch线程 /8` S}g+  
//等待子线程返回 Rl"" aZ  
try{ -cHX3UAEI  
if(bFirst) \o j#*aL^  
{ .1F^=C.w  
nFileLength = getFileSize(); 5Y&s+|   
if(nFileLength == -1) o[!g,Gmoh  
{ ^f,('0p->  
System.err.println("File Length is not known!"); 9GZKT{*  
} y[l19eU  
else if(nFileLength == -2) \ns#l@B  
{ SAEr$F^  
System.err.println("File is not access!"); %8V/QimHU  
} !Ax7k
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else _;BN;].  
{ x6ig,N~AO  
for(int i=0;i<nStartPos.length;i++) E5M*Gs  
{ IPl>bD~=p  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); m dC.M$  
} "]nbM}>  
for(int i=0;i<nEndPos.length-1;i++) xe
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{ 66%#$WH#  
nEndPos = nStartPos[i+1]; 4565U  
} ?~aM<rcZ  
nEndPos[nEndPos.length-1] = nFileLength; 9 0[gXj  
} 1b'1vp  
} t _Q/v
 
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//启动子线程 1!/ U#d"  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; h(I~HZ[K&T  
for(int i=0;i<nStartPos.length;i++) BcT|TX+ct  
{ )(&g\  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), J|Lk::Ri  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 4\?I4|{pC  
nStartPos,nEndPos,i); m)q;eQs  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); i)0*J?l=  
fileSplitterFetch.start(); I@ch 5vl4  
} @Ns^?#u~  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 48n>[ FMSR  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); J680|\ER  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", R9yK"  
nEndPos = " + nFileLength); '8>#`Yba  
// fileSplitterFetch[nPos.length-1].start(); &,fBg6A%  
d `Q$URn|  
 { Lt\4h  
//等待子线程结束 oS$&jd  
//int count = 0; 79a{Zwdd9j  
//是否结束while循环 CPGXwM=   
boolean breakWhile = false; 1H@GwQ|<=  
=?57*=]0M  
/ GJ"##<  
while(!bStop) ?/{ qRz'C<  
{ A{;b^IK  
write_nPos(); /PIU@$DV  
Utility.sleep(500); JPiC/  
breakWhile = true; ,KIa+&vJW@  
/v;g v[  
iYv6B6o/99  
for(int i=0;i<nStartPos.length;i++) d<qbUk3;  
{ slHlfWHq  
if(!fileSplitterFetch.bDownOver) (^9q7)n  
{ \x x<\8Qr_  
breakWhile = false; &tQ,2RT  
break; :%A1k2  
} >lyUr*4PX  
} r[M]2h  
if(breakWhile) GA6Z{U{XS  
break; vUgLWd  
t_,iV9NrZ  
7esG$sVj(  
//count++; 42Vy#t/HC  
//if(count>4) E[htNin.B~  
// siteStop(); Ajq;\-:  
} ,vW.vq<{q3  
eJ%~6c`@!  
0c7&J?"wE  
System.err.println("文件下载结束！"); nUhD41GJ  
} uiE9#G  
catch(Exception e){e.printStackTrace ();} ozkN&0  
} n4k.tq  
ERGDo=j  
2v`VtV|B  
//获得文件长度 J`}/+WN7  
public long getFileSize() ?$;_a%v6  
{ u;&`_=p  
int nFileLength = -1; .(CzsupY_q  
try{ ILF
"m;  
URL url = new URL(siteInfoBean.getSSiteURL()); XOgX0cRC4  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); WqY:XE+?\  
httpConnection.setRequestProperty("User-Agent","NetFox"); J%f5NSSU{6  
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'/;#{("  
int responseCode=httpConnection.getResponseCode(); -1S+fUkiK/  
if(responseCode>=400) Ax0u \(p<^  
{ Qh/yPO
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processErrorCode(responseCode); DWk'6;e4j  
return -2; //-2 represent access is error N.xmHvPk  
} @/anJrt  
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String sHeader; $hndb+6q  
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8xg:ItJaA0  
for(int i=1;;i++) Ao`9fI#q  
{ ^;W,:y&  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); IH[/fd0  
//Utility.log(in.readLine()); dWD9YIYf  
sHeader=httpConnection.getHeaderFieldKey(i); A>7'W\R  
if(sHeader!=null) g6QkF41nG  
{ RS<c&{?  
if(sHeader.equals("Content-Length")) jc Ie<i;  
{ N<Y-]xS  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); i0p"q p  
break; 09|d<  
} kfm8F8sxl  
} >4~{CXZ  
else wvT!NN K2  
break; 5>}L3r>a;  
} C"IPCJYn  
} G*ym[  
catch(IOException e){e.printStackTrace ();} i7e{REBXb  
catch(Exception e){e.printStackTrace ();} zMtK_ccQ  
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A8c'CMEm  
Utility.log(nFileLength); rm3~]  
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return nFileLength; ZwO&G\A^  
} Om>6<3n  
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//保存下载信息（文件指针位置） _k5KJKvr  
private void write_nPos() Cd|V<BB9
 
{ ET=q 1t8  
try{ _i}6zxqw  
output = new DataOutputStream(new FileOutputStream(tmpFile)); bhe|q`1,E  
output.writeInt(nStartPos.length); v8 6ls[lzu  
for(int i=0;i<nStartPos.length;i++) 7zR7v  
{ /MQd[03]  
// output.writeLong(nPos); Q9%N>h9  
output.writeLong(fileSplitterFetch.nStartPos); qG=`'%,m  
output.writeLong(fileSplitterFetch.nEndPos); xiA9X]FB  
} `Ph4!-6#  
output.close(); 8.Y6r  
} m&2<?a}l  
catch(IOException e){e.printStackTrace ();} `jP\*k`~]  
catch(Exception e){e.printStackTrace ();} r(cS{oni  
} ut-UTW  
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t&0n"4$d'  
//读取保存的下载信息（文件指针位置） & r\z9!
 
private void read_nPos() $G*$j!  
{ >K50 h  
try{ oh&
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DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); I!# 42~\  
int nCount = input.readInt(); %\r4c*O1q  
nStartPos = new long[nCount]; H1hj` '\"<  
nEndPos = new long[nCount]; '7xmj:.==  
for(int i=0;i<nStartPos.length;i++) ,6a'x~y<r  
{ ]MUuz'<
 
nStartPos = input.readLong(); [Y'Xop6G  
nEndPos = input.readLong(); g&BF#)7C  
} 5Z`f)qE  
input.close(); *QAK9mc  
} !u\X,.h  
catch(IOException e){e.printStackTrace ();} q7m-} mBN~  
catch(Exception e){e.printStackTrace ();} $stJ+uh  
} eW7;yH  
@BW~A@8  
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private void processErrorCode(int nErrorCode) SwSBQq%h]M  
{ [[[p@d/Y  
System.err.println("Error Code : " + nErrorCode); HlI*an  
} q ,}W.
 
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//停止文件下载 ^(UL$cQ>  
public void siteStop() fS!%qr  
{ Sfh\4h$H  
bStop = true; "MK:y[+*  
for(int i=0;i<nStartPos.length;i++) LG&~#x  
fileSplitterFetch.splitterStop(); eCk}B$ 2  
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} M@s2T|bQw  
} MK~viSgi  
//负责部分文件的抓取 u4#BD!W  
**FileSplitterFetch.java a7OD%yQ  
*/ 10}\7p8  
package NetFox;
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import java.io.*; ~{U~9v^v(  
import java.net.*; MH!'g7iK8  
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public class FileSplitterFetch extends Thread { /lAt&0  
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String sURL; //File URL H$;K(,'  
long nStartPos; //File Snippet Start Position oDM}h +  
long nEndPos; //File Snippet End Position 6^UeEmjc  
int nThreadID; //Thread's ID JBi<TDm/  
boolean bDownOver = false; //Downing is over 'iUfr@  
boolean bStop = false; //Stop identical Ou8@7S  
FileAccessI fileAccessI = null; //File Access interface +?nW  
+a"Asvw2  
",`fGu )  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException -4;{QB?  
{ {gK i15t  
this.sURL = sURL; s{`r$:!  
this.nStartPos = nStart; J<u,Y= -~  
this.nEndPos = nEnd; tY%c-m  
nThreadID = id; [g_f`ZJ=  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 bWUo(B#*I  
} :m^eNS6:  
Z
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public void run() YX!%R]c%  
{ waO*CjxE:  
while(nStartPos < nEndPos && !bStop) *sZOws<  
{ Dr,{V6^  
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" 0K5 /9  
try{ 2+ >.Z.pX  
URL url = new URL(sURL); ak0KrVF  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); { S4?L8  
httpConnection.setRequestProperty("User-Agent","NetFox"); V
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String sProperty = "bytes="+nStartPos+"-"; 1ciP+->$  
httpConnection.setRequestProperty("RANGE",sProperty); t<~riFs]  
Utility.log(sProperty); O^F%ssF8  
h^?[:XBeav  
5JIa?i>B  
InputStream input = httpConnection.getInputStream(); ,?<jue/bd  
//logResponseHead(httpConnection); :=UeYm @  
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{C|#<}1  
byte[] b = new byte[1024]; }oj$w?Ex  
int nRead; }4 P@`>e/`  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) tjuW+5O  
{ P0k|33;7L  
nStartPos += fileAccessI.write(b,0,nRead); u5$\E]+_  
//if(nThreadID == 1) :$dGcX}  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); }g5h"N\$o  
} )Xl/|YD  
}!lLA4XRr  
tJbOn$]2"  
Utility.log("Thread " + nThreadID + " is over!"); j}#48{  
bDownOver = true; h,rGa\X~0  
//nPos = fileAccessI.write (b,0,nRead); EX=+TOkAf  
} Yf7n0Etd,  
catch(Exception e){e.printStackTrace ();} 9\R:J"X  
} o/2\8   
} &}YB!6k h^  
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//打印回应的头信息 gB71~A{J  
public void logResponseHead(HttpURLConnection con) %Kd8ZNv  
{ LN" bGe  
for(int i=1;;i++) DU({Ncge
 
{ q~_Nv5r%O  
String header=con.getHeaderFieldKey(i); = 14'R4:  
if(header!=null) {jJUS>  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); +\\*Iy'xK  
Utility.log(header+" : "+con.getHeaderField(header)); 2JUX29rER  
else _ZC4O&fL  
break; .A&Ey5  
} 1Jd82N\'  
} UI_|VU>J  
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public void splitterStop() #W~5M ?+  
{ R]m`v: 9  
bStop = true; lVARe3#  
} q !EJs:AS  
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05=O5<l  
} J55K+  
#fzvK+  
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/* `P)1RTVx  
**FileAccess.java n<"?+bz"<  
*//文件访问(定位，写) `0=0IPVd  
package NetFox; hG2btmBh
t  
import java.io.*; NA]7qb%%<  
&z 1A-O v  
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public class FileAccessI implements Serializable{ o-lb/=K+  
*;,=x<  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 (|bMtT?"x  
RandomAccessFile oSavedFile; gTH1FR8$y  
long nPos; i"F'n0*L  
jE&kN$.7j  
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public FileAccessI() throws IOException Olj]A]v}  
{ dV<M$+;s]  
this("",0); ,B5
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} k#c BBrY  
Y)hLu:P]  
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public FileAccessI(String sName,long nPos) throws IOException H{\tQ->(2  
{ })M$#%(  
oSavedFile = new RandomAccessFile(sName,"rw"); o%Vf#W  
this.nPos = nPos; t TA6 p  
oSavedFile.seek(nPos); 7B"J x^  
} ^t*+hFEI  
P9B@2#  
rPaD#GA[7  
public synchronized int write(byte[] b,int nStart,int nLen) SV<*qz  
{ E,c~.jYc  
int n = -1; k]qZOO}  
try{ = EyxM  
oSavedFile.write(b,nStart,nLen); CbQ@l@d]  
n = nLen; kZU8s'C  
} (|'w$  
catch(IOException e) q&<#)#+  
{ Zv7@  
e.printStackTrace (); L}XEROTR  
} Gqk"%irZ  
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return n; d%t]:41=Z  
} [l-zU}u&v  
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~  
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} fX[,yc;  
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8kW9.   
/* :54|Z5h|  
**SiteInfoBean.java vEtogkFA"  
*/ pcur6:8W!  
package NetFox; O.&6J/  
 7z<!2  
pqMvYF  
public class SiteInfoBean { ^nbze  
>B8)Wb:  
>z>UtT:  
private String sSiteURL; //Site's URL puZ<cV e/  
private String sFilePath; //Saved File's Path k5!k3yI  
private String sFileName; //Saved File's Name F|xXMpC.f  
private int nSplitter; //Count of Splited Downloading File n 8AND0a1C  
,=$yvZs4[]  
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w  
public SiteInfoBean() 
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{//nSplitter的缺省值为5

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//default value of nSplitter is 5 Y0s^9?*  
this("","","",5); 45kMIh~~X  
} B susXW$  
OiM{@  
ni2H~{]z  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) *ivbk /8  
{ Rn(|  
sSiteURL= sURL; LTzf&TZbx5  
sFilePath = sPath; \M>AN Z}  
sFileName = sName; m+OR W"o  
this.nSplitter = nSpiltter; 1 _5[5K^  
8^dGI9N  
h@{@OAu?  
} =_^g]?5i  
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public String getSSiteURL() A: 0] n  
{ *\S>dhJ4  
return sSiteURL; /jj@ =H  
}
`Z%XA>  
X\1D[n:  
Xo%Anqk  
public void setSSiteURL(String value) #y>oCB`EM  
{ +Kf::[wP7  
sSiteURL = value; D"^ogY#LK  
} Y Nq<%i!>  
5+ fS$Q  
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public String getSFilePath() N"E\o,_  
{ ^+GN8LUs  
return sFilePath; zEO 9TuBO  
} 'kx{0J?  
b]|7{yMV  
jU4Ir{f  
public void setSFilePath(String value) A)`M*(~  
{ 0 ?2#SM  
sFilePath = value; ^xqh!  
} :"QRB#EC%  
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brTB /(E  
public String getSFileName() <78>6u/W%  
{ IgFz[)  
return sFileName; \H" (*["&  
} Qz$.t>@V=  
rtzxMCSEU  
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public void setSFileName(String value) C y&L,  
{ ait/|a  
sFileName = value; `q xg  
} Q2fa]*Z
5  
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public int getNSplitter() ~z< ? Wh  
{ ]h|GaHiE  
return nSplitter; F'*{Fk h  
} aqyXxJS8  
MT&i5!Z  
|faXl3|  
public void setNSplitter(int nCount) tGf  
{ PMTyiwlm  
nSplitter = nCount; dvXu?F55  
} zF{z_c#3@  
} ^T<<F}@q  
_C*}14 "3  
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/* }2h~o~  
**Utility.java |5FyfDaFBX  
*/ /Wj9Stj5  
package NetFox; Zd~Z`B} &  
M@gm.)d  
a]ftE\99  
public class Utility { @0)bY*njj  
VTV-$Du[}  
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^  
public Utility() \?GMtM,  
{ ~5JXY5*o  
N:d" {k  
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} )9PQj  
#=zh&`  
//线程睡眠 :ox+WY  
public static void sleep(int nSecond) N}^\$
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{ r<~1:/F|  
try{ &1VC0"YJWy  
Thread.sleep(nSecond); z}pdcQl#
 
} py,z7_Nuh  
catch(Exception e) JM!o(zbt  
{ v4 c_UFEh<  
e.printStackTrace (); ~s88JLw%&u  
} RE*SdazY?  
} 3|@Ske1%Y  
Z$+0gm\Cnw  
//日志 J.*dA j  
public static void log(String sMsg) 5$jKw\FF=  
{ 3UBG?%!$f  
System.err.println(sMsg); QZd ,GY5{  
} 7 bpV=  
M#2DI?S@  
9?]4s-~  
public static void log(int sMsg) CRS/qso[Q'  
{ mF#{"  
System.err.println(sMsg); [S*bN!t  
} G#K=n  
} :}j{NM#  
b~cN#w #  
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/* & XcY|y=W  
**TestMethod.java r6j 3A  
*/
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package NetFox; iGm[fxQ|  
e>MC 3D`5  
rbs:q
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public class TestMethod { Oi=kL{DG:s  
DmPp&  
5H>[@_u+:  
public TestMethod() 4WDh8U  
{ ///xx/weblogic60b2_win.exe Uln[UK  
try{ XG*Luc-v  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 4Yx?75/  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); gNN{WFHQX:  
SiteFileFetch fileFetch = new SiteFileFetch(bean); %5a>@K]  
fileFetch.start(); i!jxjP  
} FhS:.  
catch(Exception e){e.printStackTrace ();} vMDV%E S1t  
Oe*emUX7  
gHA"O@HgDI  
} X >C*(/a  
(|"KsGl  
RCo!sZP}  
public static void main(String[] args) 9>\s81^  
{ WHMt$W}%  
new TestMethod(); KR%DpQ&{'  
} (wnkdI{  
} '$;S?6$eW  
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