http断点续传简单实现（java)

/* T
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**SiteFileFetch.java ;h7
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*/ *vu  
package NetFox; LZApz}  
import java.io.*; 'h;x>r  
import java.net.*; ]PZ\N~T
 
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public class SiteFileFetch extends Thread { H)i%\7F5  
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SiteInfoBean siteInfoBean = null; //文件信息Bean $(;0;!t.  
long[] nStartPos; //开始位置 ,%,.c^-  
long[] nEndPos; //结束位置 9C\@10D  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Xldz&&@  
long nFileLength; //文件长度 yUu+68Z6  
boolean bFirst = true; //是否第一次取文件 8\CmM\R  
boolean bStop = false; //停止标志 x%,!px3s  
File tmpFile; //文件下载的临时信息 "y=AVO  
DataOutputStream output; //输出到文件的输出流 F6-U{+KU$!  
be~'}`>  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） Bc51 0I$c  
public SiteFileFetch(SiteInfoBean bean) throws IOException <84d Vg  
{ 1#^r5E4  
siteInfoBean = bean; n}4Lq^$  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); _u8d`7$*%  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); "9!CsloWhz  
if(tmpFile.exists ()) Z+C&?K  
{ GsC4ty  
bFirst = false; ri1:q.:I]  
read_nPos(); TS;?>J-  
} [^A>hs*  
else 3Uni{Z]Q)  
{ fnudu0k  
nStartPos = new long[bean.getNSplitter()]; |%5nV=&\  
nEndPos = new long[bean.getNSplitter()]; %1e{"_$O9  
} :faB7wduW;  
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} p`{| [<  
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public void run() [Xo}CU  
{ 2?\L#=<F  
//获得文件长度 KZ/2#`  
//分割文件 1IV R4:a  
//实例FileSplitterFetch } OAH/BW  
//启动FileSplitterFetch线程 g+M& _n  
//等待子线程返回 %Dm:|><V$b  
try{ R%^AW2   
if(bFirst) S#^-VZ~U4x  
{ LkIbvJCV  
nFileLength = getFileSize(); [5QbE$  
if(nFileLength == -1) nN!R!tJPa  
{ J1{ucFa  
System.err.println("File Length is not known!"); >X-*Hu'U#  
} ,{u'7p  
else if(nFileLength == -2) -K%~2M<  
{ A0 1D-)  
System.err.println("File is not access!"); wv_<be[?*  
} $+@xwuY'+  
else UJ6zgsD1b?  
{ 2q*aq%  
for(int i=0;i<nStartPos.length;i++) };@J)}  
{ IRl(H_.  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); +~1~f'4J  
} hXz@ (c
F  
for(int i=0;i<nEndPos.length-1;i++) 4+15`  
{  L\("  
nEndPos = nStartPos[i+1]; g\foBK:GE  
} k;?E,!{  
nEndPos[nEndPos.length-1] = nFileLength; L64cCP*  
} X"3Za[9j  
} X3,+aL`  
Ld3!2g2y7&  
"4e{Cq  
//启动子线程 OFcqouGE  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; rLOdQN  
for(int i=0;i<nStartPos.length;i++) 5RhP^:i@C  
{ D!CuE7}  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 1rQKHC:|  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), S K7b]J>  
nStartPos,nEndPos,i); w00
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Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); *q |3QHZ  
fileSplitterFetch.start(); k?'<f  
} B[nkE+s  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), \]+57^8r  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); N(BCe\FV  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", `<^1Ik[g  
nEndPos = " + nFileLength); 3WQ"3^G  
// fileSplitterFetch[nPos.length-1].start(); 2rJe
ON  
bjYaJtn  
#Do#e {=+  
//等待子线程结束 2OQDG7#Kc  
//int count = 0; B!zqvShF  
//是否结束while循环 cJ!C=J  
boolean breakWhile = false; CxRhMhvP  
yCG<qQz  
@%sr#YqY  
while(!bStop) 1I -LGe[Q  
{ +F3`?6UXz  
write_nPos(); lc2RMu  
Utility.sleep(500); FkJ
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breakWhile = true; 1xE*quhrh  
8'6$t@oT9w  
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for(int i=0;i<nStartPos.length;i++) a
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{ a#o6Nv  
if(!fileSplitterFetch.bDownOver) N"wp2w  
{ %1jApCJ  
breakWhile = false; fK{[=xMr@  
break; JDy;Jb  
} I~.d/!
>Z
 
} <OC|z3na_  
if(breakWhile) .&Ok53]b  
break;
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4%L-3Ij  
KGoHn6jM  
//count++; l`A4)8Y@  
//if(count>4) Lb} cjI:  
// siteStop(); ,dO$R.h  
} )mbRG9P  
XU19+mW=P  
J%n{R60b  
System.err.println("文件下载结束！"); XTOZ]H*^  
} x3++JG  
catch(Exception e){e.printStackTrace ();} bR;Zc  
} C5^eD^[c  
`DPR >dd@  
ko%B`
 
//获得文件长度 $ZOKB9QccC  
public long getFileSize() (66DKG   
{ p>@S61 & [  
int nFileLength = -1; c&JYbq  
try{ QP?Deltp  
URL url = new URL(siteInfoBean.getSSiteURL()); $=-Q]ld&]  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); s"solPw  
httpConnection.setRequestProperty("User-Agent","NetFox"); @\UoZv(  
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int responseCode=httpConnection.getResponseCode(); ^sjL@.'m$N  
if(responseCode>=400) L!]~J?)  
{ pt!Q%rXm  
processErrorCode(responseCode); 3]9twfF 'J  
return -2; //-2 represent access is error Jqt&TqX@s  
} >`@yh-'r  
S=wJ{?gzAK  
njy^<7;  
String sHeader; V^U1o[`  
i!=28|_  
^QKL}xiV:  
for(int i=1;;i++) &MlBpI  
{ <.h\%&'U  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); !tNJLOYf  
//Utility.log(in.readLine()); Fc"&lk4e  
sHeader=httpConnection.getHeaderFieldKey(i); *!gj$GK@%  
if(sHeader!=null) QFfKEMN  
{ X}5a
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if(sHeader.equals("Content-Length")) d$G<g78D  
{ @}e'(ju%R  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); MK<VjpP0(  
break; 9A4h?/  
} @-ma_0cZQ  
} /@.c 59r  
else Q:x:k+O-  
break; ~BVK6  
} h!*++Y?&0  
} WSY&\8
 
catch(IOException e){e.printStackTrace ();} yT>t[t60/S  
catch(Exception e){e.printStackTrace ();} Q l
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Utility.log(nFileLength);
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return nFileLength; H<SL=mb;  
} elgCPX&:W  
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9o7d3ir)  
//保存下载信息（文件指针位置） #f'
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private void write_nPos() 3PonF4  
{ $J |oVVct  
try{ Dk'EKT-  
output = new DataOutputStream(new FileOutputStream(tmpFile)); xmDX1sL**  
output.writeInt(nStartPos.length); Ohm
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for(int i=0;i<nStartPos.length;i++) >q&Q4E0  
{
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// output.writeLong(nPos); !k&~|_$0@  
output.writeLong(fileSplitterFetch.nStartPos); [LonY
49  
output.writeLong(fileSplitterFetch.nEndPos); axY-Vj
 
} ?[W(r$IaE  
output.close(); LaZF=<w(  
} k:4?3zJI  
catch(IOException e){e.printStackTrace ();} bmAgB}Ior  
catch(Exception e){e.printStackTrace ();} sK:,c5^  
} {I|k@  
8i;N|:WdH  
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//读取保存的下载信息（文件指针位置） I_yIVw;  
private void read_nPos() r<oI4px  
{ {/BEO=8q2  
try{ dv0TJ 0%  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 0;)6ZU  
int nCount = input.readInt(); |zu>G9m  
nStartPos = new long[nCount]; 7[-jr;v  
nEndPos = new long[nCount]; v.1= TBh  
for(int i=0;i<nStartPos.length;i++) (oxe\Qk  
{ 'D-#,X C  
nStartPos = input.readLong(); &F}1\6{fL  
nEndPos = input.readLong(); 6QRfju'  
} =3=KoH/'  
input.close(); zJMKgw,i*  
} l\^q7cXG  
catch(IOException e){e.printStackTrace ();} 'KGY;8<x]  
catch(Exception e){e.printStackTrace ();} e![Q1!r  
} lq@Vb{Z  
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private void processErrorCode(int nErrorCode) 8mA6l0  
{ F$ .j|C1a  
System.err.println("Error Code : " + nErrorCode); $UjSP  
} 2LYd # !i  
ZZC= 7FB  
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//停止文件下载 1A-8,)  
public void siteStop() wc%  
{ ](0Vm_es  
bStop = true; x#0C+cU  
for(int i=0;i<nStartPos.length;i++) 2al~`  
fileSplitterFetch.splitterStop(); >V(2Ke Y  
) Q=G&  
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}
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} tL+8nTL  
//负责部分文件的抓取 RQ,(?I*8\  
**FileSplitterFetch.java >`NY[Mn  
*/ b=T+#Jb  
package NetFox; VP4t~$"  
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import java.io.*; M{kPEl&Z  
import java.net.*; (P#2Am$  
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public class FileSplitterFetch extends Thread {
GIVs)~/Eq  
8 (^2  
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String sURL; //File URL >q &ouVE  
long nStartPos; //File Snippet Start Position *A\NjXJl~  
long nEndPos; //File Snippet End Position SA>;]6)`(  
int nThreadID; //Thread's ID xdo{4XY^*W  
boolean bDownOver = false; //Downing is over ^y6Pkb P  
boolean bStop = false; //Stop identical E2*"~gL^,  
FileAccessI fileAccessI = null; //File Access interface ,.`^Wx6F  
6 qKIz{;  
!v;r3*#Nky  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException J#V`W&\,6  
{ w78Ius,  
this.sURL = sURL; lIjHd#q-C  
this.nStartPos = nStart; Aq'%a)Y2  
this.nEndPos = nEnd; h/TPd]  
nThreadID = id; Bh' vr3|  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 eBAB7r/7  
} KR^peWR  
^YIOS]d>8#  
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public void run() u}%&LI`.  
{ |I\A0aa  
while(nStartPos < nEndPos && !bStop) ,Vs:Lle  
{ }BogE$tc  
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try{ d7^XP  
URL url = new URL(sURL); 8e\v5K9  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); _&%!4n#>  
httpConnection.setRequestProperty("User-Agent","NetFox"); e4)gF*  
String sProperty = "bytes="+nStartPos+"-"; sId5pY!  
httpConnection.setRequestProperty("RANGE",sProperty); aq5<Ks`r  
Utility.log(sProperty); E7eVg*Cvi  
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&HXSO,@  
InputStream input = httpConnection.getInputStream(); FY|x<-f  
//logResponseHead(httpConnection); (x^|  
=-VV`  
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byte[] b = new byte[1024]; |%V.Lae  
int nRead; fBLd5  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) qBNiuV;*  
{ `X^e}EGWu  
nStartPos += fileAccessI.write(b,0,nRead); YqJIp. Z  
//if(nThreadID == 1) ^w12k2a  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); fcZOsTj  
} `
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(&*F`\  
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Utility.log("Thread " + nThreadID + " is over!"); blN1Q%m6  
bDownOver = true; Qx,G3m[}  
//nPos = fileAccessI.write (b,0,nRead); .4Ny4CMHZ  
} o7T|w~F~R  
catch(Exception e){e.printStackTrace ();} Q~@8t"P  
} ?0(B;[xEJ  
} O^xt  
nDOIE)#  
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//打印回应的头信息 rODKM-7+  
public void logResponseHead(HttpURLConnection con) 2DC#PX)i  
{ 3 #wj
-  
for(int i=1;;i++) ;p_X7N  
{ !xc7~D@om(  
String header=con.getHeaderFieldKey(i); y^A$bTQq  
if(header!=null) QLUe{@ivc  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); $($SQZK&  
Utility.log(header+" : "+con.getHeaderField(header)); ^`!Daqk  
else $"FdS,*qKl  
break; F:@Ixk?E  
} UJH{vjIv  
} @ubz?5  
\fz j fZ1n  
5VTbW   
public void splitterStop() -&EmEXs%  
{ JgB# EoF  
bStop = true; (>K$gAQH  
} L&N"&\K2U  
qC4-J)8Wk  
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} HxMsH5;  
0l=}v%D  
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/* ;9PM?Iy[  
**FileAccess.java $;CC lzw  
*//文件访问(定位，写) kUUq9me&o  
package NetFox; #~x5}8  
import java.io.*; *[5  
SHk[X ]Uo  
ZYsFd_  
public class FileAccessI implements Serializable{ EDo@J2A  
@(cS8%wK  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 -"zu"H~t4  
RandomAccessFile oSavedFile; 8[C6LG  
long nPos; ,2TqzU;  
Y2X1!Em>B  
S
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public FileAccessI() throws IOException S0+zq<  
{ upDQNG>d  
this("",0); u,m-6@il  
} 1955(:I  
JLu0;XVK  
y2R=%EFh6  
public FileAccessI(String sName,long nPos) throws IOException re!8nuBsA  
{ ]CZLaID~  
oSavedFile = new RandomAccessFile(sName,"rw"); v
VYduvw  
this.nPos = nPos; V8yX7yx  
oSavedFile.seek(nPos); FZnHG;af  
} .NT&>X~.V  
zcKC5vqb  
ElXe=5L\#  
public synchronized int write(byte[] b,int nStart,int nLen) 6EU4  
{ \v
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int n = -1; 5gD)2Q6  
try{ Y/0O9}hf  
oSavedFile.write(b,nStart,nLen); j>*SJtq7  
n = nLen; $Jm2,Yv  
} N >!xedw=  
catch(IOException e) gJ.6m&+  
{ h`]/3Ma*:  
e.printStackTrace (); &XRFX 5gP  
} @6q$Zg/  
=BS'oBn^6  
XQOprIJ U  
return n; SSLshY~d  
} ^qx\e$R  
a{*'pY(R0$  
({KAh?  
} dCP Tpm  
 s7o*|Xv  
#`4^zU)  
/* t4@g;U?o  
**SiteInfoBean.java 6\Vu#r  
*/ MN
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package NetFox; g u =fq\`  
X-$td~r  
)6E*Qz  
public class SiteInfoBean { A9UaLSe  
!>y}Xq{bm3  
+)JqEwCrq  
private String sSiteURL; //Site's URL |
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private String sFilePath; //Saved File's Path /JeqoM"x  
private String sFileName; //Saved File's Name W<91m*  
private int nSplitter; //Count of Splited Downloading File &PuJV +y  
M5kHD]b  
^3|$wB=  
public SiteInfoBean() bM^A9BxD  
{//nSplitter的缺省值为5 \a2oM$PX  
//default value of nSplitter is 5 GFdJFQio  
this("","","",5); sK-|xU.  
} jL+}F/~r  
'uACoME@  
hav?mnVJ  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) N#['fg'  
{ sLa)~To
 
sSiteURL= sURL; *rz(}(r  
sFilePath = sPath; Gd6 ;'ZCmY  
sFileName = sName; 7Y|>xx=v  
this.nSplitter = nSpiltter; o>;0NF| }  

pZ~>l=-  
$
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} qm8n7Z/  
E'S;4B5?  
PnIvk]"Ab  
public String getSSiteURL() vDeG20.?Z  
{ e1^{  
return sSiteURL; "8iiRzt#  
} VgsCwJ9w  
K'5sn|)  
<6b\i5j  
public void setSSiteURL(String value) %r  
{ Sd$]b>b4O  
sSiteURL = value; wJos'aTmE  
} Rc:cVK  
KT;C RO>  
$F@L$&~  
public String getSFilePath() yp2'KES>  
{ D*T$ v   
return sFilePath; F `pyhc>1;  
} 2mG&@
E  
9CK\tx&  
X:SzkkVl7  
public void setSFilePath(String value) FQ|LA[~  
{ _2gT1B  
sFilePath = value; me[J\MJ;w^  
} |
6(qg5"  
)-9w3W1r  
wO_pcNYZ8  
public String getSFileName() "Yfr"1RmO  
{ JM+sHHs  
return sFileName; dJQ }{,+6  
} kJ#[UCqzM  
i_9Cc$Qh<  
DA4edFAuE  
public void setSFileName(String value) HzG~I8o(d  
{ # McK46B z  
sFileName = value; )kL`&+#>  
} ."F'5eTT~  
,Og[[0g  
=hugnX<9  
public int getNSplitter() `hK>bHj  
{ 36^C0uNdX  
return nSplitter; <r7qq$  
} TRySl5jx@  
DX&lBV  
&3 XFgHo  
public void setNSplitter(int nCount) 6cQeL$,SQ  
{ 9N*S-Po=  
nSplitter = nCount; u"#6_-0y  
} L{F[>^1Sb  
} H_vGa!_  
oa<%R8T?@  
o~`KOe  
/* 6R'z3[K9  
**Utility.java 5Ei4$T
 
*/ `NB6Of*/  
package NetFox; GzEv
p  
mV++7DY  
FT[of(g^  
public class Utility { _X)`S"EsJ  
8z)J rO}  
dj2w_:&W  
public Utility() :zp9L/eh  
{ Wf{&D>  
)Nt'Z*K*  
]Wg&r Y0  
} +N2R'Phv  
p>h}k_s  
//线程睡眠 I''X\/|  
public static void sleep(int nSecond) qlm7eS"sy  
{ 5gKXe4}\/|  
try{ yF@72tK  
Thread.sleep(nSecond); ZKF #(G  
} <Gj]XAoe%  
catch(Exception e) ^KUM4. 6  
{ :V~ AjV  
e.printStackTrace (); *hlinQKs  
} n'9&q]GN|  
} "Tnmn@  
vRMGNz_P7[  
//日志 ks7id[~&iY  
public static void log(String sMsg) yC\!6pg  
{ 0,1)Sg*  
System.err.println(sMsg); iJSyi;l|  
} UHS{X~CS e  
M5c *vs  
.(Tf$V  
public static void log(int sMsg) C *]XQ1F4  
{ `P jS  
System.err.println(sMsg); g?{7DI`  
} IPk"{
T3  
} I>:.fHvUC  
;\ gat)0n%  
, %A2wV  
/* xM13OoU  
**TestMethod.java wpa^]l  
*/ zTg&W7oz  
package NetFox; pykRi#[UrX  
&Vbcwv@  
@!mjjeG+1  
public class TestMethod { xPMX\aI|l  
FB n . 4  
^3ysY24Q  
public TestMethod() {jo"@&2S  
{ ///xx/weblogic60b2_win.exe %:Y'+!bX  
try{ [-2Tj)P C  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 5Eu`1f?  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); G&#l3bkQ  
SiteFileFetch fileFetch = new SiteFileFetch(bean); VE*&t>I  
fileFetch.start(); Q#}c5TjVr  
} 2YpJ4.  
catch(Exception e){e.printStackTrace ();} =z9FjK  
Z(hRwIOF  
a3^({;k!0  
} j,v2(e5:  
Kbcr-89Gv~  
4n/CSAT1  
public static void main(String[] args) p/Ri|FD6  
{ 54%h)dLDy  
new TestMethod(); V#\iO  
} J(kC  
} B^BbA-I  
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