http断点续传简单实现（java)

/* ?xuWha@:  
**SiteFileFetch.java VxE;t
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*/ ,eSpt#M  
package NetFox; 7jGfQ  
import java.io.*; 0}po74x*r  
import java.net.*; CZ>Ujw=&k  
qRz /$|.  
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public class SiteFileFetch extends Thread { ])q,mH  
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SiteInfoBean siteInfoBean = null; //文件信息Bean =E-o@#BS  
long[] nStartPos; //开始位置  QB !%  
long[] nEndPos; //结束位置 <U8w#dc  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 2*] [M,L0c  
long nFileLength; //文件长度 a'd=szt  
boolean bFirst = true; //是否第一次取文件 NC iBn>=:  
boolean bStop = false; //停止标志 SiJ{  
File tmpFile; //文件下载的临时信息 70EH~  
DataOutputStream output; //输出到文件的输出流 wOLV?Vk  
eU.C<Tv:8  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 2B
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public SiteFileFetch(SiteInfoBean bean) throws IOException o_5[}d  
{ c2L\m*^o  
siteInfoBean = bean; !#W3Q  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); B ]sVlbt  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); M.bkFuh  
if(tmpFile.exists ()) ?}= $zN  
{ ~_IQ:]k  
bFirst = false; 1=e(g#Ajn\  
read_nPos(); lXEnm-_  
} ;P$ _:-C  
else qn'TIE.  
{ Sr_h
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nStartPos = new long[bean.getNSplitter()]; BB_(!omq[  
nEndPos = new long[bean.getNSplitter()]; OX?E3 <8`  
} L[<CEk  
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} G[u{! 2RS  
: %uaaFl  
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public void run() nB]mj_)R^  
{ 87m`K Str7  
//获得文件长度 Wtp=1  
//分割文件 #%L_wJB-  
//实例FileSplitterFetch -B(p8YH  
//启动FileSplitterFetch线程 1QnaZhu'  
//等待子线程返回 w,_LC)9  
try{ O[z6W.  
if(bFirst) }:QoYNq  
{ >/NegJh'F}  
nFileLength = getFileSize(); .~TI%&#  
if(nFileLength == -1) 2|U6dLZ!  
{ 3+q-yP#X  
System.err.println("File Length is not known!"); A,(9|#%L  
} P% 8U  
else if(nFileLength == -2) 3,#v0#  
{ Om_ "X6  
System.err.println("File is not access!"); hh2&FI  
} lR
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else [nlq(DGJhp  
{ `:jF%3ks+0  
for(int i=0;i<nStartPos.length;i++) e)}=T0 s  
{ TtQd#mSI\  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 7!)VOD8Z  
} PYzTKjw  
for(int i=0;i<nEndPos.length-1;i++) e2g`T{6M  
{ [xQ.qZ[h&  
nEndPos = nStartPos[i+1]; Qstd;qE~  
} wDW/?lT&  
nEndPos[nEndPos.length-1] = nFileLength; M(uJ'Ud/!  
} E>O@Bv  
} de[NIDA;`  
`LKf$cx(A  
;%cW[*Dw  
//启动子线程 *P&lAyt6  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; g>`D!n::n  
for(int i=0;i<nStartPos.length;i++) 8dJ+Ei~M  
{ GiXs`Yt|  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), "L8Hgwg  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Ekh)l0 l  
nStartPos,nEndPos,i); G({VK  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); N P5K1:  
fileSplitterFetch.start(); .q!
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} = C/F26=|  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), jl>wvY||  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); /b/  6*&  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Og?GYe^_  
nEndPos = " + nFileLength); %?F$3YN,  
// fileSplitterFetch[nPos.length-1].start(); ^+gD;a|t  
NzN"_ojM  
Zv?"1Y< L  
//等待子线程结束 y{~tMpo<  
//int count = 0; t**d{P+  
//是否结束while循环 m9]Ge]  
boolean breakWhile = false; 1u(n[<WtT_  
{Z Ld_VGW  
Hw62'%  
while(!bStop) k![H;}W  
{ 2MW7nIEs  
write_nPos(); Z|)1ftcC  
Utility.sleep(500); V 'fri/Z  
breakWhile = true; 8Z)wot  
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bfpoX,:   
for(int i=0;i<nStartPos.length;i++)  ':DL  
{ -.L )\  
if(!fileSplitterFetch.bDownOver) FIu^Qd  
{ a4Z e!l(  
breakWhile = false; 2Uu!_n}tNF  
break; KuL+~  
} 7{9M ^.}  
} ic l]H  
if(breakWhile) <'BsQHI  
break; .CNwuN\  
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rEbH<|  
//count++; .'h^  
//if(count>4) oiD{Z  
// siteStop(); ub+XgNO  
} G|||.B8  
pRUQMPn (  
6z:/ma^  
System.err.println("文件下载结束！"); 73SH[
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} {.DY\;Q  
catch(Exception e){e.printStackTrace ();} uc|ej9N  
} bqaj~:}@  
[$:L|V!{  
8U7dd[  
//获得文件长度 TefPxvd  
public long getFileSize() _j*I\  
{ 2U"2L^oKI  
int nFileLength = -1; :JZV=@<T  
try{ 9E0x\%2K  
URL url = new URL(siteInfoBean.getSSiteURL()); \+0l#t$  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); I[w5V;>*  
httpConnection.setRequestProperty("User-Agent","NetFox"); 8!@}\6qM  
~k}O"{ y  
SUW=-M  
int responseCode=httpConnection.getResponseCode(); A>HCX 4i  
if(responseCode>=400) 7W5Cm\  
{ 3-kL0Q["  
processErrorCode(responseCode); sYvlf0  
return -2; //-2 represent access is error vo2GFo  
} @2-;,VL3  
m}S}fH(  
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String sHeader; ?{5}3abB`  
X|QokAR{$>  
L{&=SR.  
for(int i=1;;i++)  Vo%Z|  
{ {z;4t&5  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); " SP6o  
//Utility.log(in.readLine()); Xs'qwL~{`  
sHeader=httpConnection.getHeaderFieldKey(i); >
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if(sHeader!=null) w
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{ 1?.NJ<)F  
if(sHeader.equals("Content-Length")) 6':Egh[;  
{ w ykaf  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 6UL9+9[C  
break; N.ZuSkR
M  
} 2"%f:?xV{  
} ` K0PLxSv  
else ]&`
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break; S1m5z,G  
} #EB Rc4>,  
} D(&WEmm\B  
catch(IOException e){e.printStackTrace ();} F~bDg tN3  
catch(Exception e){e.printStackTrace ();}  !$!%era`  
iM6(bmc.  
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Utility.log(nFileLength); gr{*wYL  
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return nFileLength; {))Cb9'  
} |YfJ#Agm+  
?[Ma" l>  
Q~P|=*  
//保存下载信息（文件指针位置） F2EX7Crj  
private void write_nPos() ?32i
1F!  
{ 2~B5?(g  
try{ ugTnz$  
output = new DataOutputStream(new FileOutputStream(tmpFile)); A4b+:MQ*OX  
output.writeInt(nStartPos.length); Nw-U*y  
for(int i=0;i<nStartPos.length;i++) ?1] \3nj  
{ U}5]Vm$]  
// output.writeLong(nPos); ;cp||uO  
output.writeLong(fileSplitterFetch.nStartPos); CVEo<Tz  
output.writeLong(fileSplitterFetch.nEndPos); 82?LZ?!PD  
} kc}|L9  
output.close(); AR&l9R[{N  
} NLxR6O4}8  
catch(IOException e){e.printStackTrace ();} "ctZ"*  
catch(Exception e){e.printStackTrace ();} 9U=6l]Np  
} =A$
d)&  
cR*~JwC:  
AEElaq.B  
//读取保存的下载信息（文件指针位置） {MDM=;WP_  
private void read_nPos() ]#G1 ]U  
{ FT-=^VA\  
try{ }n'W0Sa  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); t)~$p#NS  
int nCount = input.readInt(); V{x[^+w7X~  
nStartPos = new long[nCount]; 3a=\$x@  
nEndPos = new long[nCount]; LX=v _}l J  
for(int i=0;i<nStartPos.length;i++) o=xMaA  
{ 0<fQjXn  
nStartPos = input.readLong(); t=s.w(3t  
nEndPos = input.readLong(); ziM@@$.F  
} S;%k?O7v  
input.close(); `9P`f4x  
} /g!Xe]Ss  
catch(IOException e){e.printStackTrace ();} $&Z#2 X.  
catch(Exception e){e.printStackTrace ();} eIN0T;1T  
} P7l3ZH( g  
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private void processErrorCode(int nErrorCode) h|lH`m^  
{ kXlI*h  
System.err.println("Error Code : " + nErrorCode); >Ad`_g6Wew  
} ,Ik~E&Ku2'  
r)Ml-r=  
_u6MSRX[6$  
//停止文件下载 )a`kL,  
public void siteStop() W{j(=<|<  
{ N%e^2O)  
bStop = true; ]&P 4QT)f  
for(int i=0;i<nStartPos.length;i++) *Ue#Sade  
fileSplitterFetch.splitterStop(); }9;mtMR$  
b' ~WS4xlD  
}LLQ+  
} 5 [4{1v  
} 4nh0bIN1  
//负责部分文件的抓取 HYY+Fv5  
**FileSplitterFetch.java dNov= w  
*/ [6/8O
 
package NetFox; x(~V7L>"i  
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import java.io.*; dk]A,TB*2  
import java.net.*; Ol|
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CLJn+Y2  
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public class FileSplitterFetch extends Thread { M&H,`gm  
[ <k&]Kv  
BJ fBYH,M  
String sURL; //File URL B7oUS}M  
long nStartPos; //File Snippet Start Position 2=1qmQE  
long nEndPos; //File Snippet End Position @3FQMs4  
int nThreadID; //Thread's ID LW">9;n  
boolean bDownOver = false; //Downing is over &!HG.7AY  
boolean bStop = false; //Stop identical 6q `Un}  
FileAccessI fileAccessI = null; //File Access interface HsT6 #K  
%kgT=<E'  
1'dZ?`O  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ;sz_W%-;@  
{ Xr88I^F;  
this.sURL = sURL; (|3?wX'2U  
this.nStartPos = nStart; B8!$?1*^a  
this.nEndPos = nEnd; .1ep8O<  
nThreadID = id; #cb9g   
fileAccessI = new FileAccessI(sName,nStartPos);//定位 I'N!j>5oX  
} BuxU+  
<DII%7q,6/  
PGVP0H+RV  
public void run() U#XW}T=|  
{ l\d[S]  
while(nStartPos < nEndPos && !bStop) E33x)CP  
{ 6wXy;!2  
T]b&[?p|a[  
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try{ n3 Rf:j^R  
URL url = new URL(sURL); lh!8u<yv*  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); [TxvZq*4  
httpConnection.setRequestProperty("User-Agent","NetFox"); .SSPJY(  
String sProperty = "bytes="+nStartPos+"-"; 4! F$nmG)  
httpConnection.setRequestProperty("RANGE",sProperty); V!e*J,g  
Utility.log(sProperty); t^%)d7$  
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InputStream input = httpConnection.getInputStream(); BIg2`95F|  
//logResponseHead(httpConnection); M*~XpT3  
#]^M/y h  
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byte[] b = new byte[1024]; RK)ikLgp  
int nRead; |I|,6*)xg  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) %+UTs'I  
{ ft iAty0n  
nStartPos += fileAccessI.write(b,0,nRead); Lw?>1rTT/  
//if(nThreadID == 1) V|{~9^  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos);   &._Mh  
} ZuP3/d  
<xH! Yskc  
s9fEx-!y  
Utility.log("Thread " + nThreadID + " is over!"); C/ ]Bx  
bDownOver = true; ;$qc@)Uwp  
//nPos = fileAccessI.write (b,0,nRead); ?}u][akM  
} [d>2F  
catch(Exception e){e.printStackTrace ();} {e0aH `me  
} !thFayq  
} Z0wH%
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H;Gs0Qi;  
//打印回应的头信息  Lu[Hz8  
public void logResponseHead(HttpURLConnection con) Lg2PP#r  
{ WW7E*kc  
for(int i=1;;i++) oB'5':  
{ "39mhX2  
String header=con.getHeaderFieldKey(i); ~uB@oKMru  
if(header!=null) \rS-}DG  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); m+ #G*  
Utility.log(header+" : "+con.getHeaderField(header)); aFh'KPhe  
else G,(Xz"`,  
break; [RTo[-ci2  
} >Tn[CgH]7  
} '}F9f?  
m]{/5L  
^lK!tOeO  
public void splitterStop() yC!>7@m  
{ p-7?S^!l  
bStop = true; x'%vL",%  
} 8*uaI7;*  
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t6)R37  
} |;U3pq)  
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*;lb<uLv  
/* xz7CnW1  
**FileAccess.java F^=y+}]=  
*//文件访问(定位，写) jo0
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package NetFox; i/C0 (!  
import java.io.*; -}8r1jQH;  
e >7Ka\  
0-d&R@lX.  
public class FileAccessI implements Serializable{ 1d&Q E\2}  
qs9r$o.\l  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ~BBh4t&  
RandomAccessFile oSavedFile; %fh-x(4v  
long nPos; Cth<xn(Q  
LXR>M>a`  
bF
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public FileAccessI() throws IOException PK_2  
{ Y)M-?|4  
this("",0); Ow-;WO_HQ  
} 4!?4Tc!X  
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public FileAccessI(String sName,long nPos) throws IOException oL9ELtb]s  
{ -^rdB6O6j  
oSavedFile = new RandomAccessFile(sName,"rw"); JNu+e#.Y  
this.nPos = nPos; dcE(uf  
oSavedFile.seek(nPos); `_J>R  
} q1/mp){  
;Z,l};b  
MA7&fNjB  
public synchronized int write(byte[] b,int nStart,int nLen)
#vPk XcP  
{ grJ(z)c  
int n = -1; w&&)v~Y_  
try{ .O{_^~w_q  
oSavedFile.write(b,nStart,nLen); @DAaCF
8  
n = nLen; 7~H$p X  
} ;$4: &T  
catch(IOException e) QCfR2Nn}  
{ i \.&8  
e.printStackTrace (); gO]8hLT  
}
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+^4HCyW  
W9A F}  
return n; >R\!Qk  
} 6%&w\<(SG  
8%b-.O:_$  
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} p
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(IAR-957pN  
/* W:2j.K9!  
**SiteInfoBean.java 1.a:iweN  
*/ tA K=W$r  
package NetFox; ip*UujmNyR  
cs]3Rp^g  
:&s8G*  
public class SiteInfoBean { ]TsmWob  
2]tW&y_i  
AxCFZf5  
private String sSiteURL; //Site's URL [Lf8*U"  
private String sFilePath; //Saved File's Path 4&B|rf  
private String sFileName; //Saved File's Name *+J`Yk7}  
private int nSplitter; //Count of Splited Downloading File O+~@S~  
\Oe8h#%  
' KNg;  
public SiteInfoBean() 4}<[4]f?|  
{//nSplitter的缺省值为5 p.vxrk`c  
//default value of nSplitter is 5 Q+E)_5_sA  
this("","","",5); F[0w*i&u5  
} z+nq<%"'  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) b.xG'  
{ //^{u[lr  
sSiteURL= sURL; /J&_ZDNV~  
sFilePath = sPath; LT/*y=  
sFileName = sName; s09&A]G  
this.nSplitter = nSpiltter; _2<d6@}
 
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Ntpw(E<$f  
} j<A;
i  
,.uI>  
m$$sNPnT  
public String getSSiteURL() %D+NrL(  
{ XC,by&nY<y  
return sSiteURL; %lGg}9k'  
} TnPx.mwK\  
5^36nEoA(  
F\+!\b*lP  
public void setSSiteURL(String value) 4?aNJyV%&  
{ +`.,6TNVlY  
sSiteURL = value; #:[CF:  
} 9:*a9xT,  
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public String getSFilePath() N<aMUVm  
{ )AAPT7!U  
return sFilePath; 6W N(Tw  
} zUJPINDb  
~*RBMHs  
l>@){zxL  
public void setSFilePath(String value) j.29nJ  
{ ;QQ/bM&I  
sFilePath = value; sW@_q8lG  
} xGK"`\V  
C*Dco{ EQ>  
8s6^!e&  
public String getSFileName() lJU]sZ9~b  
{ cb_nlG!  
return sFileName; IjRUL/\=  
} VOrBN
u  
?qczMck_  
|Q#CQz  
public void setSFileName(String value) 6b h.5|  
{ e|.a%,Dcy  
sFileName = value;  *l-F  
} l gTw>r   
n`|CDKb  

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public int getNSplitter() bU_P@GKB  
{ S| l%JM^  
return nSplitter; :n$?wp  
} $Q56~AP  
.&n;S';"  
lAPPng`  
public void setNSplitter(int nCount) =b#,OXQ  
{ ZG_iF#  
nSplitter = nCount; o1rH@D6/-  
} :74G5U8%  
} 5m rkw  
EZ)GW%Bm2  
W^1)7
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/* 8,?*eYNjb  
**Utility.java QQX7p!~E  
*/ {
3\{aZ8)  
package NetFox; a O(&<  
|=sjGf  
a*Ng+~5)6  
public class Utility { p/Lk'h~  
Yq-7!  
^a;412  
public Utility() :X#'ELo|  
{ vN`JP`IBx  
$Q*^c"&  
+ZPn[|  
} ?Yh
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hbTJXP~~?  
//线程睡眠 fBct%M 3  
public static void sleep(int nSecond) _l&.<nz  
{ v^(J+d_>   
try{ 2I1CKA:7g  
Thread.sleep(nSecond); D? FWSv  
} uE,j$d  
catch(Exception e) "o$)z'q
 
{ QhmOO
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e.printStackTrace (); Eilo;-El  
} qJEtB;J'  
} ~DUOL~E  
~X1<x4P\  
//日志 ^97\TmzP{  
public static void log(String sMsg) l=^^l`  
{ ]YwvwmZ  
System.err.println(sMsg); D>"!7+t|@a  
} iLJBiZ+  
jI,?*n<  
=
1% <  
public static void log(int sMsg) r*W&SU9Z  
{ &W-1W99auE  
System.err.println(sMsg); S *K0OUq  
} qiyJ4^1  
} \Gz 79VW  
rZG6}<Hx  
yI_MYL[  
/* >7nOR  
**TestMethod.java >Ms_bfSK  
*/ @7OE:& #V  
package NetFox; 3Vb/Mn!k  
??=su.b  
D 13bQ&\B-  
public class TestMethod { 5:X^Q.f;  
vU,;asgy  
&3bhK5P  
public TestMethod() }n$I #G}\/  
{ ///xx/weblogic60b2_win.exe 84M*)cKR~  
try{ WOuk> /  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); F48W8'un  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); PZO8<d  
SiteFileFetch fileFetch = new SiteFileFetch(bean); a #Pr)H  
fileFetch.start(); o.KE=zp&z  
} m[6c{$A/w  
catch(Exception e){e.printStackTrace ();} tf?"AY4  
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|bv7N@?e  
} \-R\xL  
Z6_E/S  
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public static void main(String[] args) K.::P84m;  
{ Tlz~o[`&  
new TestMethod(); r
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} be:=-B7!  
} )dZ1$MC[  
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