http断点续传简单实现（java)

/* M|NQoQ8q  
**SiteFileFetch.java MU%7'J :_  
*/ >,[@SF%  
package NetFox; IC?(F]$%>  
import java.io.*;  TJ1h[  
import java.net.*; +Qf}&D_  
7[PEiAI  
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public class SiteFileFetch extends Thread { |{v#'";O:
 
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SiteInfoBean siteInfoBean = null; //文件信息Bean cPv(VjS1;  
long[] nStartPos; //开始位置 h aApw(.%  
long[] nEndPos; //结束位置 wZs 2aa  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 f}J(nz>Sh  
long nFileLength; //文件长度 A; wT`c  
boolean bFirst = true; //是否第一次取文件  +IO>%  
boolean bStop = false; //停止标志 m7DKC,  
File tmpFile; //文件下载的临时信息 ^GyZycch  
DataOutputStream output; //输出到文件的输出流 'qvj[lpGr  
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v  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 8CZ%-}-%$  
public SiteFileFetch(SiteInfoBean bean) throws IOException 7B)1U_L0H  
{ X'-Yz7J?o  
siteInfoBean = bean; aydNSgu  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); x x4GP2  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); k%FA:ms|k  
if(tmpFile.exists ()) 1)MDnODJ  
{ UKQ"sC  
bFirst = false; #=={h?UDT  
read_nPos(); [orL.D]  
} ^,acU\}VqP  
else >F7w]XH  
{ ^ RA'E@"  
nStartPos = new long[bean.getNSplitter()]; _XV%}Xb'  
nEndPos = new long[bean.getNSplitter()]; :x)H!z P  
} KLg1(W(  
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} 0N.h:21(4  
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public void run() mm-s?+&M;  
{ l@4_D;b3o"  
//获得文件长度 NQk aW)  
//分割文件  5&&4-  
//实例FileSplitterFetch b-&iJ &>'  
//启动FileSplitterFetch线程 V&M*,#(?  
//等待子线程返回
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try{ ~&i4FuK  
if(bFirst) h[ DNhR  
{ Y%s:oHt  
nFileLength = getFileSize(); Cbw *?9d  
if(nFileLength == -1) GM%+yS}(P  
{ mgq!)  
System.err.println("File Length is not known!"); C82_)@96  
} ~~tTr$  
else if(nFileLength == -2) GXtMX ha,  
{ &S,D;uhF  
System.err.println("File is not access!"); \<4N'|:  
} ;b$P*dSG}  
else H_DCdUgC'  
{ {PHH1dC{  
for(int i=0;i<nStartPos.length;i++) ~VGnE:  
{ yB b%#GW  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ) 7/Cg  
} ?+yr7_f3*  
for(int i=0;i<nEndPos.length-1;i++) pP. _%5  
{ Mt[yY|Ec|  
nEndPos = nStartPos[i+1]; )g0lI  
} m>@hh#kBg  
nEndPos[nEndPos.length-1] = nFileLength; X'Ss#s>g  
} {Su?*M2y  
} 3nq?Y8yac  
h)KHc/S  
/WrB>w  
//启动子线程 51#*8u+L  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; f-ltV<C_  
for(int i=0;i<nStartPos.length;i++) m|a9T#B(  
{ @IT[-d  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), g9_zkGc7  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), l
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nStartPos,nEndPos,i); a~$XD(w^  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); = tv70d'  
fileSplitterFetch.start(); jkAjYR.  
} R=D]:u<P  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 2w?q7N%  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 54 lD+%E  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", =~#mF<z5  
nEndPos = " + nFileLength); ZoW1Cc&p  
// fileSplitterFetch[nPos.length-1].start(); H|9t5   
)H8_.]|  
ZlT }cA/n  
//等待子线程结束 o2/:e  
//int count = 0; =C"[o\]VV  
//是否结束while循环 E C?}iP  
boolean breakWhile = false; <I+kB^Er  
iHa?b2=)  
9:j?Jvw$  
while(!bStop) +C(-f  
{ 5ut| eD`3  
write_nPos(); ]33!obM  
Utility.sleep(500); 5cSiV7#Y:  
breakWhile = true; _y@28t  
(jc@8@Wo.  
j3j?2#vR  
for(int i=0;i<nStartPos.length;i++) L^J4wYFTO  
{ _^NX`<&  
if(!fileSplitterFetch.bDownOver) L9GLjRp-  
{ :4ryi&Y  
breakWhile = false; [FFr}\}bY  
break; L2}\Ah"[  
}
7]=&Q4e4  
} E^F"$Z"N  
if(breakWhile) z0"t]4s  
break; a:FU- ^B4~  
N*Y[[N(  
pUIN`ya[[  
//count++; 5ggyk0  
//if(count>4) .OPknC  
// siteStop(); dwOfEYC  
} K'A+V  
Llfl I  
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System.err.println("文件下载结束！"); c%&,(NJ]K  
} ]'.qRTz'\t  
catch(Exception e){e.printStackTrace ();} Y
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} `3TR`,=  
T:^.; ZY  
qv!(In>u  
//获得文件长度 tUu' gs|  
public long getFileSize() xfk -Ezv  
{ SN6 QX!3  
int nFileLength = -1; a>4/2#J  
try{ b 74!Zw  
URL url = new URL(siteInfoBean.getSSiteURL());  2&6D`{"P  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); * #yF`_p  
httpConnection.setRequestProperty("User-Agent","NetFox"); u>XXKlW:  
,NO[Piok  
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int responseCode=httpConnection.getResponseCode(); gtKih  
if(responseCode>=400) Kz'GAm\  
{ H_xHoCLI  
processErrorCode(responseCode); Y3~Uz#`SU  
return -2; //-2 represent access is error Np\
NStx2  
} #2=l\y-#  
:ez76oGyc  
6 AO(A *  
String sHeader; D+T/ Z)  
'5}hm1,  
#X(2  
for(int i=1;;i++) S|tD8A  
{ bTs2$81[  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); MN: {,#d0  
//Utility.log(in.readLine()); ^-%'ItVO  
sHeader=httpConnection.getHeaderFieldKey(i); V_i&@<J  
if(sHeader!=null) :3F[!y3b  
{ >~g-  
if(sHeader.equals("Content-Length")) xM())Z|2  
{ 7mt
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nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); )xp3 ElH  
break; [I;C6p  
} 6;E3|st1X  
} :k9T`Aa]  
else D;sG9Hky  
break; &Wy>t8DIK  
} :EW1I>}_  
} rBJ`=oz  
catch(IOException e){e.printStackTrace ();} G[}v?RLI  
catch(Exception e){e.printStackTrace ();} QRQ{Bq}#  
bI.hG32  
&5}YTKe}|  
Utility.log(nFileLength); 1_7p`Gxt[/  
c{^1`(#?  
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return nFileLength; "Lvk?k )hx  
} q:_:E*o  
0 Rb3|te  
D)MFii1J~  
//保存下载信息（文件指针位置） V;^-EWNj  
private void write_nPos() YM#'+wl}`  
{ kNP-+o  
try{ tk0m[HN@eV  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 2fdN@iruB  
output.writeInt(nStartPos.length); y/@Bhzc  
for(int i=0;i<nStartPos.length;i++) PE.UNo>o  
{ ;FI'nL  
// output.writeLong(nPos); ,`U>BBBLv  
output.writeLong(fileSplitterFetch.nStartPos); z<Z0/a2'1  
output.writeLong(fileSplitterFetch.nEndPos); ]prw=rD  
} 5NkF_&S_1  
output.close(); e!=7VEB  
} aGWO3Nk  
catch(IOException e){e.printStackTrace ();} -qpvV
LR,  
catch(Exception e){e.printStackTrace ();} |Ja5O  
} Ju5Dd\  
R;,5LS&*a  
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//读取保存的下载信息（文件指针位置） '`tFZfT  
private void read_nPos() RJ'za1@z;b  
{ iTevl>p!  
try{ T6SYXQd>.  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ^?|4<Rm  
int nCount = input.readInt(); yfwR``F  
nStartPos = new long[nCount]; 1/bTwzR.g  
nEndPos = new long[nCount]; =2*2$  
for(int i=0;i<nStartPos.length;i++) .`*;AT  
{ pv4#`.m  
nStartPos = input.readLong(); [4EIy
"  
nEndPos = input.readLong(); EqHToD I3  
} +dCR$<e9
r  
input.close(); n=f?Q=h\3  
} 5k=04=Iyh#  
catch(IOException e){e.printStackTrace ();} @WXRZEz  
catch(Exception e){e.printStackTrace ();} /g0' +DP  
} 1z; !)pG.  
5T"h7^}e  
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private void processErrorCode(int nErrorCode) vWW Q/^  
{ /:-ig .YY  
System.err.println("Error Code : " + nErrorCode); cEXd#TlY~X  
} >;G7ty[RX7  
"
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8~!h8bkC  
//停止文件下载 @6[aLF]F  
public void siteStop() ! qtj1.w  
{ Yjy%
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bStop = true; ?(khoL t  
for(int i=0;i<nStartPos.length;i++) kQ[2
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fileSplitterFetch.splitterStop(); b;`MHEzw&q  
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} +pv..\  
} 2#R0Bd  
//负责部分文件的抓取 EE9eG31|r  
**FileSplitterFetch.java 4X:mb}(  
*/ #VZ-gy4$\B  
package NetFox; '*U_!RmQ  
EAs^i+/  
I]#x0?D  
import java.io.*; F(U(b_DPM  
import java.net.*; U~|)=+%O  
bHDZ=Ik  
98|1K>C  
public class FileSplitterFetch extends Thread { (6)|v S  
=m;cy0))  
(^ J2(  
String sURL; //File URL YyY?<<z%  
long nStartPos; //File Snippet Start Position vA?3kfL|#  
long nEndPos; //File Snippet End Position .%\R L/  
int nThreadID; //Thread's ID YRaF@?^Gn  
boolean bDownOver = false; //Downing is over lo7>
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boolean bStop = false; //Stop identical I0bkc3  
FileAccessI fileAccessI = null; //File Access interface (>\4%(pnD  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Tn'o$J  
{ _k)EqPYu@  
this.sURL = sURL; L3S29-T  
this.nStartPos = nStart; H9=8nLb.  
this.nEndPos = nEnd; ?,r}@89pY  
nThreadID = id; U@".XIDQ  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 cS",Bw\  
} dY?>:ce  
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Jb!s#g   
public void run() wemhP8!gc  
{ K &G  
while(nStartPos < nEndPos && !bStop) _10I0Z0  
{ \uOR1z  
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try{ "2 qivJ  
URL url = new URL(sURL); E`q)vk   
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 3Q#3S  
httpConnection.setRequestProperty("User-Agent","NetFox"); 1[(/{CClB  
String sProperty = "bytes="+nStartPos+"-"; WQNFHRfO*n  
httpConnection.setRequestProperty("RANGE",sProperty); s&W^?eKr  
Utility.log(sProperty); fp$U%uj  
p=dM2>  
1{CVd m<9  
InputStream input = httpConnection.getInputStream(); E(an
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//logResponseHead(httpConnection); .#Lu/w' -M  
Wl{}>F`W[  
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byte[] b = new byte[1024]; HA;G{[X  
int nRead; `_.(qg   
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) GOY!()F  
{ cx+%lco!  
nStartPos += fileAccessI.write(b,0,nRead); |EP=<-|  
//if(nThreadID == 1) 0PJ7o#}_{@  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); +Y440Tz  
} :w26d-QR(  
kO'NT:  
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Utility.log("Thread " + nThreadID + " is over!"); z?g\w6  
bDownOver = true; Ft 2u&Rtx  
//nPos = fileAccessI.write (b,0,nRead); q4KYC!b  
} $&FeR*$|g  
catch(Exception e){e.printStackTrace ();} hWiBLip,z  
} iR{*XE   
} T@on ue7  
}
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uVLKR PY  
//打印回应的头信息 |BE`ASW;  
public void logResponseHead(HttpURLConnection con) F
)
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{ F44KbUH  
for(int i=1;;i++) cy( WD
#^  
{ S!.H _=z%p  
String header=con.getHeaderFieldKey(i); JX2@i8[~  
if(header!=null) FSkz[D_}  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); /\UFJ  
Utility.log(header+" : "+con.getHeaderField(header)); PG'+vl  
else Hge0$6l  
break; bjB4  
} F@kd[>/[  
} = ^_4u%}  
Et+WLQ6)  
g+/m:(7[s|  
public void splitterStop() t(5PKD#~Dc  
{ o_on/{qz  
bStop = true; ffoLCx4o0E  
} x10u?@  
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05/'qf7P,U  
} *BAR`+;U  
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/* Eh/Z4pzT  
**FileAccess.java FR? \H"'x  
*//文件访问(定位，写) ^Qa!{9o[  
package NetFox; 8;1,saA_9  
import java.io.*; }\/ 3B_X6N  
clO9l=g  
[X\~J &kD  
public class FileAccessI implements Serializable{ )|`|Usn#[  
T6fm`uL&L  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 8AuOe7D9A  
RandomAccessFile oSavedFile; &BS*C} },  
long nPos; )lDmYt7me  
< r7s,][&  
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public FileAccessI() throws IOException Eu1t*>ZL  
{ /O&{fo  
this("",0); /YT _~q=:  
} 6PdLJ#LS  
TIYo&?Z)  
|.Vs
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public FileAccessI(String sName,long nPos) throws IOException Xjs`iK=w  
{ U3b&/z|b?  
oSavedFile = new RandomAccessFile(sName,"rw"); 5!*@gn  
this.nPos = nPos; IT=<p60"  
oSavedFile.seek(nPos); (~OP)F).  
} j$Wd[Ja+O  
 y)GH=@b  
'4]_~?&x  
public synchronized int write(byte[] b,int nStart,int nLen) LMTz/M  
{ \zx$]|AQ  
int n = -1; 8qWN~Gk1p{  
try{ ((cRe6  
oSavedFile.write(b,nStart,nLen); ;?.w!|6  
n = nLen; ~x6<A\  
} pUD(5v*0R  
catch(IOException e) ^SC2k LI  
{ pRH'>}rtuH  
e.printStackTrace (); \_l4li  
} }C!g
x6  
,Aw Z%  
w:c9Z=KX  
return n; "xV0$%  
} U\GuCw  
Wf:LYL  
#b
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} lFZl}
x  
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i)th] 1K%  
/* /_qW?LKG/  
**SiteInfoBean.java _bn "c@s  
*/ +sT S1t  
package NetFox; 2uLBk<m5c  
E4, J"T|@  
oe<DP7e  
public class SiteInfoBean { Fxv5kho  
\-8S"  
5jAS1XG  
private String sSiteURL; //Site's URL 6KDm#7
J  
private String sFilePath; //Saved File's Path wDDNB1_E  
private String sFileName; //Saved File's Name  L30$  
private int nSplitter; //Count of Splited Downloading File ;cf
PS  
TyY%<NCIb  
E<sd\~~A:  
public SiteInfoBean() Q?>DbT6  
{//nSplitter的缺省值为5 +t%1FkI\  
//default value of nSplitter is 5 B *%ey?  
this("","","",5); q~`dxq`}  
} n?*r,)'  
89Ir}bCr  
pp@O6  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) HZqk)sN  
{ +Jh1D_+!9  
sSiteURL= sURL; `BVXF#sb  
sFilePath = sPath; 2N{^V?:  
sFileName = sName; P^AI*tH"m  
this.nSplitter = nSpiltter; 1my1m  
-&l%CR,U  
z(Z7[#.  
} ?j&ZzK'#^  
8([ MR  
BbiyyRa  
public String getSSiteURL() _y&XFdp  
{ V*DDU]0k  
return sSiteURL; sI.p( -KQ  
} C1>zwU_zo  
!jvl"+_FV  
 nZ)E @  
public void setSSiteURL(String value) !yd]~t 5Q  
{ j WSgO(y  
sSiteURL = value; /24}>oAH  
} v: veKA  
cy
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8L+A&^qx  
public String getSFilePath() $01csj  
{ 5|cRHM#  
return sFilePath; zf&:@P{  
} +#\7 #Y  
!nq`PyMR  
r.lHlHl  
public void setSFilePath(String value) \E[6wB>uN%  
{ {,u})U2  
sFilePath = value; _a f $0!  
} Paeq  
U>OAtiq JX  
vZW[y5  
public String getSFileName() :%Oz:YxC/  
{ 2W2T  
return sFileName;
9ln=f=  
} /!MVpi'6&  
^/6P~iK'  
zvVo-{6  
public void setSFileName(String value) H>W8F2VT  
{ vK[%cA"  
sFileName = value; \7%#4@;?  
} U1HG{u,"y  
\A,zwdt P  
#lg R"%  
public int getNSplitter() (^(l=EN-<  
{ iEZ+Znon  
return nSplitter; [sjkm+ ?  
} k}p8"'O  
g8l6bh$}  
7~F~'
V  
public void setNSplitter(int nCount) ca,W:9#.xn  
{ +wJ!zab`  
nSplitter = nCount; gnjhy1o  
} V.z8 ]iG  
} \PU
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[61*/=gWe  
HFI0\*xn(  
/* TYb$+uY  
**Utility.java b,YNCb]H  
*/ KbtV>  
package NetFox; '5
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vXRY/Zzj1  
-F[@)$L  
public class Utility { e).;;0  
|oke)w=gn  
4l%1D.3-O  
public Utility() 9aY8`B  
{ 3V?x&qlP>  
E "}@SaB-  
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} fO&`A:JY  
?KOw~-u  
//线程睡眠 bY=[ USgps  
public static void sleep(int nSecond) QcW8A ,\q  
{ vM6W64S  
try{ nAEyL+6U  
Thread.sleep(nSecond); [GI~ &  
} m|B=&#  
catch(Exception e) .WqqP  
{ %&yPl{  
e.printStackTrace (); %z-*C'j5H  
} >e>3:~&2  
} xNf}f 9l  
"H).2{3(x  
//日志 P .m@|w&.K  
public static void log(String sMsg) ,M;9|kE*  
{ Ly+UY.v"  
System.err.println(sMsg); R-S<7Q3E0=  
} 9+^)?JUYll  
xBVOIc[4(  
Td|u@l4B  
public static void log(int sMsg) `a4&_`E,p  
{ q\?s<l63  
System.err.println(sMsg); z{ :;Rb  
} w,LmAWZ4Y  
} oT):#,s  
5'I+%66?h$  
Oh*~+/u}q  
/* 3- Kgz  
**TestMethod.java 4SJ aAeIZ  
*/ *x|%Nua"  
package NetFox; ORs:S$Nt$  
lx%c&~.DiB  
dZ`Y>wH_  
public class TestMethod { KFd +7C9  
qY#*LqV  
rM
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public TestMethod() ^?`fN'!p  
{ ///xx/weblogic60b2_win.exe Ud/>oaW?s  
try{ I*rUe#$  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 0%f}Q7*R  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); .<m]j;|6  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ^6W}ZLp  
fileFetch.start(); #49l\>1z  
} +#IUn
  
catch(Exception e){e.printStackTrace ();} B}"R@;N  
opa/
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LLx0X
O@  
} *V&M5  
NM. e4  
B!'K20"gF  
public static void main(String[] args) 4%0s p  
{ kQ+y9@=/g  
new TestMethod(); ?N{\qF1Mz  
} m H:Un{,  
}  u$?!  
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