http断点续传简单实现（java)

/* *?uUP  
**SiteFileFetch.java {cLWum[SY  
*/ Je9Z:s[  
package NetFox; 2~g-k3  
import java.io.*; F-ofR]|)>  
import java.net.*; 4f8XO"k7t=  
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public class SiteFileFetch extends Thread { }93FWo.  
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SiteInfoBean siteInfoBean = null; //文件信息Bean pxedj  
long[] nStartPos; //开始位置 =+T0[|gc(r  
long[] nEndPos; //结束位置 ,98 F  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 o_Y?s+~i[/  
long nFileLength; //文件长度 VZ`YbY  
boolean bFirst = true; //是否第一次取文件 t!J>853  
boolean bStop = false; //停止标志 I/A%3i=H  
File tmpFile; //文件下载的临时信息 g5Io=e@s  
DataOutputStream output; //输出到文件的输出流 !- QB>`7$  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） Y`-q[F?\y  
public SiteFileFetch(SiteInfoBean bean) throws IOException ]|w~{X!b4  
{ 7zE1>.  
siteInfoBean = bean; m zoH$@  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); =X[?
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tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); !XI9evJw  
if(tmpFile.exists ()) GtIAsC03  
{ )y:))\>
 
bFirst = false; RN@)nc_  
read_nPos(); bZfq?  
} 4,X CbcC  
else G^SJhdO(Q  
{ _]Ob)RUVH  
nStartPos = new long[bean.getNSplitter()]; qyKR]%yzi  
nEndPos = new long[bean.getNSplitter()]; =+DhLH}8  
} P2s\f;Dwr  
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} BSd.7W;cS=  
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public void run() ><S2o%u~  
{ &LB`  
//获得文件长度 Ic!x y  
//分割文件 2Y[n  
//实例FileSplitterFetch #X$s5H  
//启动FileSplitterFetch线程 hmuhq:<f  
//等待子线程返回 8JR&s  
try{ :ntAU2)H  
if(bFirst) jHatUez4O  
{ b{-|q6  
nFileLength = getFileSize(); \21Gg%W5AE  
if(nFileLength == -1) LqJV  
{ :-hVbS0I  
System.err.println("File Length is not known!"); R!X+-  
} gCkR$.-E  
else if(nFileLength == -2) &%/T4$'+Y+  
{ Q\xDAOEL  
System.err.println("File is not access!"); G OG[^T  
} V7gL*,3>=  
else eUR+j?5I  
{ N;!!*
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for(int i=0;i<nStartPos.length;i++) 8$iHd  
{ 7)RvBc
M  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); OuWRLcJ!  
} ScVbo3{m*T  
for(int i=0;i<nEndPos.length-1;i++) j!k$SDA-  
{ r#w7qEtD  
nEndPos = nStartPos[i+1]; Z]k@pR !  
} 4JO16  
nEndPos[nEndPos.length-1] = nFileLength; 3N2d@R  
} ?GLCd7TP  
} w6mYLK%  
Z
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!>Q\Y`a,*  
//启动子线程 ^vxNS[C`;  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; q?]KZ_a  
for(int i=0;i<nStartPos.length;i++) aAn p7\7  
{ 017nhI  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), K g.O2F77  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), `0q=Z],  
nStartPos,nEndPos,i); 7z/O#Fbs  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 4:b'VHW.  
fileSplitterFetch.start(); @PQd6%@  
} tk8\,!
9Q  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), L@Qvj-5e  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); .i|nn[H &  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", <~_XT>`y  
nEndPos = " + nFileLength);
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// fileSplitterFetch[nPos.length-1].start(); fF9hL3h?)  
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//等待子线程结束 $cm9xW&  
//int count = 0; F1M:"-bda  
//是否结束while循环 .We{W{  
boolean breakWhile = false; c_.Fe'E  
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:+ 1Wmg  
while(!bStop) $ZB`4!JxG  
{ W*v3B.  
write_nPos(); ZUz7h^3@  
Utility.sleep(500); C,LosAd  
breakWhile = true; NB.'>Sar  
#67 7,dn  
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for(int i=0;i<nStartPos.length;i++) MTNC{:Q  
{ ,\RR@~u'  
if(!fileSplitterFetch.bDownOver) jPx}-_jM  
{ {L.uLr_?e  
breakWhile = false; _nX8f &  
break; -m ;n}ECg  
} 08%Bx~88_%  
} K,U8vc  
if(breakWhile) 37jrWe6xwp  
break; })J}7@VPO  
#ZnNJ\6  
7i#/eR
ui  
//count++; !3DY#  
//if(count>4) +.|RH  
// siteStop(); S9%,{y  
} *{Z=)k%  
42}8es.aa  
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System.err.println("文件下载结束！"); 91q  
} HGd
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catch(Exception e){e.printStackTrace ();} 0plX"NU  
} F>X<=YO0  
qTMY]=(  
p:0X3?IG3  
//获得文件长度 wg\p&avvb  
public long getFileSize() \ptjnwC^O  
{ k6o8'6wN  
int nFileLength = -1; SQx&4R.  
try{ Ve)BF1YG  
URL url = new URL(siteInfoBean.getSSiteURL()); z%lJWvaA7  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); vEGI  
httpConnection.setRequestProperty("User-Agent","NetFox"); 9zIqSjos"  
)1HWD]>4  
{c*5 )x!  
int responseCode=httpConnection.getResponseCode(); CHD.b%_|  
if(responseCode>=400) L2~'Z'q  
{ T"gk^.  
processErrorCode(responseCode); nf1 `)tXG  
return -2; //-2 represent access is error P$*Ngt  
} \ a(ce?C  
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String sHeader; hv\Dz*XTs0  
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for(int i=1;;i++) B##X94aTT  
{ Z;RUxe|<k  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); JAXD\StC  
//Utility.log(in.readLine()); DGS,iRLnA  
sHeader=httpConnection.getHeaderFieldKey(i); qE]e+S?57a  
if(sHeader!=null) $z 5kA9  
{ ha 2=O  
if(sHeader.equals("Content-Length")) %:;g|PC  
{ P*VZ$bUe5@  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); v+SdjFAY  
break; Np ru  
} e+{lf*"3  
} ;ny9q  
else jF/S2Ty2  
break; 8]R{5RGy  
} n5^57[(  
} ~<s =yjTu+  
catch(IOException e){e.printStackTrace ();} oDi+\0  
catch(Exception e){e.printStackTrace ();} Qh-:P`CN
 
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Utility.log(nFileLength); lCl5#L9  
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return nFileLength; SO[ u4b_"h  
} xk7Dx}  
*kYGXT,f]  
N#t`ZC&m'  
//保存下载信息（文件指针位置） PiCGZybCA  
private void write_nPos() D3P/: 4  
{ t4/ye>P &  
try{ }<l:~-y|  
output = new DataOutputStream(new FileOutputStream(tmpFile)); !@N?0@$/  
output.writeInt(nStartPos.length); uN>5Eh&=Pf  
for(int i=0;i<nStartPos.length;i++) h8(>$A-  
{ PwthYy  
// output.writeLong(nPos); 0\B{~1(^  
output.writeLong(fileSplitterFetch.nStartPos); 0_MtmmL.  
output.writeLong(fileSplitterFetch.nEndPos); d%-/U!z?  
} %d(= >  
output.close(); X?n=UebO^  
} \hBzP^*"n  
catch(IOException e){e.printStackTrace ();} VO=Ibu&X  
catch(Exception e){e.printStackTrace ();} uZ\+{j=  
}
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//读取保存的下载信息（文件指针位置） 2l^_OrE!  
private void read_nPos() 7C,giCYU  
{ y)CvlI  
try{ [A"=!e$<  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); GdVF;  
int nCount = input.readInt(); jY]51B
 
nStartPos = new long[nCount]; Gsb^gd  
nEndPos = new long[nCount]; N)R5#JX  
for(int i=0;i<nStartPos.length;i++) *L$_80  
{ " r o'?  
nStartPos = input.readLong(); 1 ptyiy  
nEndPos = input.readLong(); NX.5u8Pf  
} .8!\6=iJB  
input.close(); v:yU+s|kN  
} y1Z>{SDiq  
catch(IOException e){e.printStackTrace ();} 0BhcXHt  
catch(Exception e){e.printStackTrace ();} ]W`?0VwF  
} ,$>l[G;Bm  
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'@Rk#=85Z  
private void processErrorCode(int nErrorCode) &r4|WM/ec  
{ s*<T'0&w0S  
System.err.println("Error Code : " + nErrorCode); )`R}@(r.  
} %!(C?k!\  
PM#3N2?|E  
qIsf!1I?  
//停止文件下载 6L$KMYHE  
public void siteStop() 4"(rZWv  
{ Ddpcov  
bStop = true; ,p#B5Dif/  
for(int i=0;i<nStartPos.length;i++) ,I x>.^|  
fileSplitterFetch.splitterStop(); /w(g:e  
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W0~G`A(:;  
} %<(d%&~  
} |l+5E   
//负责部分文件的抓取 8B?U\cfa^  
**FileSplitterFetch.java CW?Z\  
*/ h@G~'\8t  
package NetFox; LSJ.pBl\X  
tO:JB&vO2  
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import java.io.*; HdB>CVuh  
import java.net.*; KU9FHN  
}YFM40H  
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public class FileSplitterFetch extends Thread { Q[rZ1z  
UF#!6"C@  
jga\Ry=nw  
String sURL; //File URL /[\g8U{5B}  
long nStartPos; //File Snippet Start Position 1(IZ,*i  
long nEndPos; //File Snippet End Position A`Y^qXFb`  
int nThreadID; //Thread's ID /3~L#
jS  
boolean bDownOver = false; //Downing is over 2[qfF6FHA  
boolean bStop = false; //Stop identical vB_3lAJt@  
FileAccessI fileAccessI = null; //File Access interface ~nfOV*  
x"NQatdq  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 2J&~b8:  
{ >WDHRC  
this.sURL = sURL; kexV~Q  
this.nStartPos = nStart; e7xBi!I)~  
this.nEndPos = nEnd; oYZ  4F  
nThreadID = id; 7K
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fileAccessI = new FileAccessI(sName,nStartPos);//定位 :e;6oC*"q  
} DlE,aYB  
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public void run() k/
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{ qfE0J;e   
while(nStartPos < nEndPos && !bStop) cVL|kYVWT  
{ |zpy!X3  
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try{ f/#Id]B  
URL url = new URL(sURL); 'A7!@hVy  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection ();
8lYA6A  
httpConnection.setRequestProperty("User-Agent","NetFox"); wPjq B{!Q  
String sProperty = "bytes="+nStartPos+"-"; ZxwrlaA  
httpConnection.setRequestProperty("RANGE",sProperty); %N<5ST>(  
Utility.log(sProperty); hDJG.,r  
)PP yJ@M  
8e*skL  
InputStream input = httpConnection.getInputStream(); K%\r[NF  
//logResponseHead(httpConnection); yT@Aj;X0v  
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@`4T6eL5  
byte[] b = new byte[1024]; ^WO3,  
int nRead; {jB>]7  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) e,e(t7c?d  
{ 'QT~o-U  
nStartPos += fileAccessI.write(b,0,nRead); kWZY+jyt P  
//if(nThreadID == 1) W{"sB:E  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ?I[8rzBWU  
} lTMY|{9  
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v7 *L3Ol  
Utility.log("Thread " + nThreadID + " is over!"); nXLz<wE  
bDownOver = true; j}ob7O&U'w  
//nPos = fileAccessI.write (b,0,nRead); 0@-4.IHl  
} M8X6!"B$Y  
catch(Exception e){e.printStackTrace ();} w8:[w  
} %%s)D4sW  
} 9efey? z  
>80k5$t  
: x&R'wX-  
//打印回应的头信息 Gc`PO  
public void logResponseHead(HttpURLConnection con) H@1'El\9  
{ $kTm"I  
for(int i=1;;i++) x:MwM?  
{ 5:IDl1f5  
String header=con.getHeaderFieldKey(i); -eF-r=FR  
if(header!=null) {kk%_q  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); //2O#Fg{/  
Utility.log(header+" : "+con.getHeaderField(header)); ?pW1}:z  
else
;um)JCXz  
break; l&+O*=#Hh  
} A[+)PkR  
} *HR pbe2  
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public void splitterStop() )Ri!  
{ FE!jN-#  
bStop = true; Ur xiaE  
} ;m7G8)I  
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} &>Ve4!i q  
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=\%
ER/  
/* dXh[Ea^  
**FileAccess.java vYV!8o.I  
*//文件访问(定位，写) p6<JpW5@_  
package NetFox; 4)w,gp  
import java.io.*; Z|n|gxe  
r&4Xf#QD6  
=Q(J!f  
public class FileAccessI implements Serializable{ !~vK[G(R  
PG63{  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 _gqqPny4$  
RandomAccessFile oSavedFile; w/*G!o-<  
long nPos; !YAX.e  
#]jl{K\f#X  
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public FileAccessI() throws IOException MWv@]P_0p!  
{ a -Pz<*  
this("",0); Ljm`KE\Q;t  
} `#ruZM066  
D;> 7y}\  
'z8FU~oU  
public FileAccessI(String sName,long nPos) throws IOException Qf( A  
{ T5u71C_wmt  
oSavedFile = new RandomAccessFile(sName,"rw"); 1- s(v)cxh  
this.nPos = nPos; ^5E9p@d"J  
oSavedFile.seek(nPos); N4+Cg t(  
} IrL%0&*hS  
2V)+ba|+  
VE
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public synchronized int write(byte[] b,int nStart,int nLen) v=@y7P1  
{ r5~W/e
E  
int n = -1; @bA5uY!  
try{ $@'BB=i  
oSavedFile.write(b,nStart,nLen); X3}eq|r9  
n = nLen; cOV9g)7^O  
} M)oKtiav*  
catch(IOException e) 'd$R
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{ &K0b3AWc  
e.printStackTrace (); `CVkjLiy  
}
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hEB5=~A_  
jV}8VK*`+  
return n; Np+PUu>  
} 5bt>MoKxv
 
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} BFW b0;+  
%!nI]|  
!vf:mMo  
/* 8+[Vo_]  
**SiteInfoBean.java %N-aLw\  
*/ :*KTpTa  
package NetFox; )K{s^]Jp  
)9`HO?   
Hnt*,C.0  
public class SiteInfoBean { jXeE]A"  
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.1[.f}g$J  
private String sSiteURL; //Site's URL '{2]:  
private String sFilePath; //Saved File's Path
c`xNTr01  
private String sFileName; //Saved File's Name G
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private int nSplitter; //Count of Splited Downloading File d/9YtG%q  
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3FR(gr$X  
public SiteInfoBean() SQ,-45@W  
{//nSplitter的缺省值为5 {ze69 h  
//default value of nSplitter is 5 a5#G48'X  
this("","","",5); hP+4{F*}-  
} |s! _;6  
^Q`5+  
aPelt`  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) gw"cX
ny  
{ Cy?]o?_?  
sSiteURL= sURL; 1]:,Xa+|S  
sFilePath = sPath; {KHI(*r;  
sFileName = sName; M3-lL;!n  
this.nSplitter = nSpiltter; ,A{Bx`o?  
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C<J*C0vQO  
} -E|"?  
Cw(e7K7&  
72Bc0Wg  
public String getSSiteURL() et+lL"&

 
{ B9NUafK=  
return sSiteURL; X6 BIZ  
} sR9$=91`  
!tTv$L>  
 ~frsgHW  
public void setSSiteURL(String value) 68z#9}  
{ Sqn>L`L
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sSiteURL = value; ?IAu,s*u  
} |V\{U j  
 <)TIj6  
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public String getSFilePath() s8,YQ5-  
{ o)5zvnu7  
return sFilePath; VkJ">0k  
} Hy3J2p9.  
W5Z-s.o  
:<P4=P P  
public void setSFilePath(String value) GPHb-  
{ + -Rf@  
sFilePath = value; W~mo*EJ'^  
} f)_<Ih\/7_  
LKvX~68  
@LI;q  
public String getSFileName() m[=SCH-;  
{ W\>O$IX^e  
return sFileName; 5Lc@=,/0  
} H"/JR  
aaU4Jl?L  
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public void setSFileName(String value) #-YbZ  
{ ?-c|c_|$  
sFileName = value; vy~6]hH  
} %q|*}l  
"J,|),Yd  

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public int getNSplitter() =Lkn   
{ MPUyu(-%{  
return nSplitter; ,mm97I  
} -E\G3/*51  
/rZk^/'  
4S'e>:  
public void setNSplitter(int nCount) Xi"9y @  
{ 7kV$O(4  
nSplitter = nCount; oA5Qk3b:  
} 5b rM..  
} Kc[^Pu  
R7rM$|n=o  
 _:\rB  
/* Q(<A Yu  
**Utility.java 'G65zz  
*/ sBZn0h@  
package NetFox; ?M'CTz}<\  
|[n\'Xy;{
 
--y,ky#  
public class Utility { Pa{DB?P  
LIG@`  
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public Utility() 5P<"I["  
{ ?:/J8s [O  
]uFJ~:R  
tiGH#~?  
} pHR`%2!"t  
o%+w:u.  
//线程睡眠 gtH^'vFZ  
public static void sleep(int nSecond) U $#^
e  
{ 2#$7!`6K  
try{ *1v3x:pQ'  
Thread.sleep(nSecond); s@~3L  
} `Zuo`GP*1  
catch(Exception e) Bs0~P 4^  
{ i +@avoW  
e.printStackTrace (); 4}D&=0IZ  
} w;@v#<q6  
} by9UwM=gp  
J
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//日志 pm+E)z6Yo  
public static void log(String sMsg) / P@P1l|I  
{ Uot(3p!S6  
System.err.println(sMsg); \68bXY.  
} _lI(!tj(  
8Q/cJ+&  
4?@5JpC9VA  
public static void log(int sMsg) $o+@}B0)  
{ ^4WZ%J#g  
System.err.println(sMsg); A?HDY_u  
} ksU& q%1  
} 9u=]D> kb  
JT}"CuC  
x!I@cP#O  
/* ){/n7*#Th%  
**TestMethod.java t_I-6`8o]  
*/ nZj&Ma7R  
package NetFox; pDP* 3  
6$PQ$  
=^M Q 4  
public class TestMethod { b/.EA'/  
=Cf@!wZ^  

 XU"G  
public TestMethod() Wx/PD=Sf&  
{ ///xx/weblogic60b2_win.exe *9KT@"v  
try{ &:d`Pik6  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); zLr:zfl  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); KDg%sgRu}  
SiteFileFetch fileFetch = new SiteFileFetch(bean); @QJPcF"  
fileFetch.start(); i`9}">7v~  
} &gV9h>Kc#  
catch(Exception e){e.printStackTrace ();} `Q+O#l?  
_Hq)@AI   
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} CiU^U|~'L  
qu1! KS  
%A `9[icy  
public static void main(String[] args) Y"5FK  
{ 4Vj]bm  
new TestMethod(); A5fzyG
 
} Kk.\P|k2  
} I&8!V)r)  
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