http断点续传简单实现（java)

/* dF$KrwDK  
**SiteFileFetch.java :OHSxb>[  
*/ gk"mr_03  
package NetFox; (Ar?QwP9>  
import java.io.*; ~Y% : 3  
import java.net.*; ,MRvuw0P  
* !X4&#xP  
5QR}IxQ  
public class SiteFileFetch extends Thread { GXO4x|08F  
*0O<bm  
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SiteInfoBean siteInfoBean = null; //文件信息Bean #De(*&y2  
long[] nStartPos; //开始位置 JdtPY~k0  
long[] nEndPos; //结束位置 <R>Q4&we(  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 NvcHv7,  
long nFileLength; //文件长度 9KXym
}  
boolean bFirst = true; //是否第一次取文件 QS\Uq(Ja\  
boolean bStop = false; //停止标志
H]BAW*}  
File tmpFile; //文件下载的临时信息 SAP;9*f1\  
DataOutputStream output; //输出到文件的输出流 8AryIgy>@  
D^nxtuT*  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） >Z}@7$(7!~  
public SiteFileFetch(SiteInfoBean bean) throws IOException B-$+UE>%  
{ XHy?  
siteInfoBean = bean; fc3 Fi'^  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); `%uK0qw"  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); .M8=^,h^K  
if(tmpFile.exists ()) B0v|{C   
{ fO#?k<p  
bFirst = false; ,pn)>  
read_nPos(); 9MT3T?IS  
} HQl~Dh0DJ  
else I:nI6gF  
{ WI6(#8^p  
nStartPos = new long[bean.getNSplitter()]; >ZX|4U[$P  
nEndPos = new long[bean.getNSplitter()]; jSB'>m]  
} 1ADv?+j)A/  
^L ]B5,}-  
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} M</Wd{.g"  
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public void run() b]w[*<f?  
{ 0:. 6rp  
//获得文件长度 ":V%(c  
//分割文件 B.}cB'|  
//实例FileSplitterFetch V(r`.75  
//启动FileSplitterFetch线程 Gh'X.?3   
//等待子线程返回 |<1M&\oaQ'  
try{ BO"qD[S  
if(bFirst) nz[ m3]  
{ zMr&1*CDX  
nFileLength = getFileSize(); [NL -!  
if(nFileLength == -1) $5x]%1R  
{ g#}tm<
 
System.err.println("File Length is not known!"); 9Yn)t#G'`F  
} y=#j`MH{>  
else if(nFileLength == -2) o~;M"  
{ .ots?Ns  
System.err.println("File is not access!"); w [L&*
 
} 1#]B^D  
else O~atNrHD  
{ 7u|%^Ao6  
for(int i=0;i<nStartPos.length;i++) {
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{ \TZ|S,FS  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); bH,M,xIL2  
} ;7L;  
for(int i=0;i<nEndPos.length-1;i++) 3 &Sp@,  
{ k1RV'  
nEndPos = nStartPos[i+1]; /eb-'m  
} !O8.#+  
nEndPos[nEndPos.length-1] = nFileLength; pu#[pa  
} HJ",Sle  
} =6
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bf
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//启动子线程 a>w~FUm*  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; I )5<DZB9  
for(int i=0;i<nStartPos.length;i++) V,m3-=q  
{ K_Re}\D  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ^\T]r<rCY  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), %W&1`^Jl  
nStartPos,nEndPos,i); &*A:[b\  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); [EruyWK  
fileSplitterFetch.start(); bLco:-G1E1  
} G%$}WA]|  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Bh,Q8%\6  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); vbaC+AiX  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", oBC]UL;8xJ  
nEndPos = " + nFileLength); s*.3ZS5  
// fileSplitterFetch[nPos.length-1].start(); a
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i&*<lff  
50*@.!^*  
//等待子线程结束 Zt_r9xs>  
//int count = 0; &}E:jt}  
//是否结束while循环 2qjyFTT  
boolean breakWhile = false; DLXL!-)z  
6<PW./rk:  
f7 wmw2  
while(!bStop) 14-]esSa  
{ dWUUxKC  
write_nPos(); h9jc,Xu5X  
Utility.sleep(500); Cdmy.gx^  
breakWhile = true; J)KnE2dw5  
;Gh>44UM[  
{:$NfW  
for(int i=0;i<nStartPos.length;i++) XfDX:b1p  
{ M9DgO4xl  
if(!fileSplitterFetch.bDownOver) ?M~  k$  
{ h;nQxmJ9  
breakWhile = false; ^N{k6
>;  
break; ,\x
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} tpZ->)1  
} Wj tft%  
if(breakWhile) OT@yPG  
break; _@K YF)  
7f* RM  
r>O|L%xpv  
//count++; \OY}GR
Kt  
//if(count>4) :X Lp  
// siteStop(); %I0}4$  
} &Sa~/!
M  
7D
9]R#-K  
]Zk}ZG>6  
System.err.println("文件下载结束！"); o[^Q y(2~  
} -yl;3K]l  
catch(Exception e){e.printStackTrace ();} }uiPvO+&p  
} a ea0+,;  
&(7$&Q  
V:>`*tlh  
//获得文件长度 d'OGVN  
public long getFileSize() USFg
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{ 87}(AO)  
int nFileLength = -1; (l_:XG)7~b  
try{ N%u  
URL url = new URL(siteInfoBean.getSSiteURL()); rs_h}+6"s  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Pk:zfC?4  
httpConnection.setRequestProperty("User-Agent","NetFox"); ^vaL8+  
5k~\or 5_  
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int responseCode=httpConnection.getResponseCode(); !5~k:1=  
if(responseCode>=400) x_W3sS]ej  
{ N<n8'XDdG  
processErrorCode(responseCode); bw5T2wYZ  
return -2; //-2 represent access is error U(Z!J6{c  
} XWXr0>!,?  
I=odMw7Hj  
7>&1nBh. f  
String sHeader; }LQ\a8]<
 
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R{`gR"*  
for(int i=1;;i++) QTE:K?  
{ 
I^:F)a:  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); bRsc-Fz6  
//Utility.log(in.readLine()); ;W~4
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sHeader=httpConnection.getHeaderFieldKey(i); ~ k<SbFp  
if(sHeader!=null) ](nH{aY!  
{ .pW o>`"  
if(sHeader.equals("Content-Length")) nALnB1  
{ qRl/Sl#F  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 4m\([EO  
break; q)k{W>O  
} OfJd/D  
} Y;g% e3nu  
else v#F-<?Vv  
break; &
=NJ  
} 7H#2WFQ7  
} @ t|3gF$X  
catch(IOException e){e.printStackTrace ();} H`5Ct  
catch(Exception e){e.printStackTrace ();} x=vK EyS@  
l=NAq_?N\  
70=(.[^+  
Utility.log(nFileLength); M}KZG'7  
=]d^3bqN  
5W{hH\E _5  
return nFileLength; :*cHA  
} gi1j/j7  
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q<EEb  
//保存下载信息（文件指针位置） gb(#DbI  
private void write_nPos() rei5{PC  
{ `V@z&n0P6  
try{ Ih3$  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 6%UY1Q.?  
output.writeInt(nStartPos.length); dE GX3 -  
for(int i=0;i<nStartPos.length;i++) 3fl7~Lw,  
{ 506V0]`/  
// output.writeLong(nPos); F1J#Y$q~L  
output.writeLong(fileSplitterFetch.nStartPos); 1OP"5f  
output.writeLong(fileSplitterFetch.nEndPos); 2+Zti8  
} UO1$UF! QC  
output.close(); k% NrL@z  
} .jaZ|nN8`  
catch(IOException e){e.printStackTrace ();} >3!DOv   
catch(Exception e){e.printStackTrace ();} LyV#j>gD  
} *F|+2?a:$  
&rP~`4Mkp  
@Kp1k> ov  
//读取保存的下载信息（文件指针位置） =Sa~\k+  
private void read_nPos() |@ *3^'  
{ K-6p'|  
try{ +dM.-wW  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 71*>L}H  
int nCount = input.readInt(); 1\IZcJ {  
nStartPos = new long[nCount]; t2U$m'(A&  
nEndPos = new long[nCount]; vbedk+dd?A  
for(int i=0;i<nStartPos.length;i++) m#;.yR  
{ [aHlu[,  
nStartPos = input.readLong(); 7JS#a=D#  
nEndPos = input.readLong(); &urb!tQ>&  
} gW}}5Xq  
input.close(); A6Q c;v+  
} 'QR4~`6I  
catch(IOException e){e.printStackTrace ();} 80HEAv,O  
catch(Exception e){e.printStackTrace ();} /cYk+c  
} @2?=3Wf  
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private void processErrorCode(int nErrorCode) Zikm?(J  
{ ]| z")gOE  
System.err.println("Error Code : " + nErrorCode); 61kO1,Uz*  
} sSV^5  
4rm87/u*0  
)%BT*)x  
//停止文件下载 X
~%IM1+L;  
public void siteStop() w0aHEvH/  
{ 7> )l{7  
bStop = true; 'z~KTDX  
for(int i=0;i<nStartPos.length;i++) dX0x Kk%#  
fileSplitterFetch.splitterStop();
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} h~:H?pj3g  
} [&Lxz~W][  
//负责部分文件的抓取 LPMb0F}"5  
**FileSplitterFetch.java sI$:V7/!  
*/ bje'Oolc  
package NetFox;
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import java.io.*; |\/~ 8qP  
import java.net.*; Etdd\^  
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public class FileSplitterFetch extends Thread { nE4l0[_  
vRxL&8`&  
a9L0f BRy  
String sURL; //File URL 0oQ/J:  
long nStartPos; //File Snippet Start Position f}A^]6MO:  
long nEndPos; //File Snippet End Position _4O[[~  
int nThreadID; //Thread's ID %$^$'6\77  
boolean bDownOver = false; //Downing is over >[hrJn[  
boolean bStop = false; //Stop identical g*^wF?t'T  
FileAccessI fileAccessI = null; //File Access interface uz8nRS s  
%bN"bxv^  
UX?X]ZYVR  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException "
1AjCHZ  
{ R+C+$?4NG  
this.sURL = sURL; %uF:)  
this.nStartPos = nStart; ayHn_  
this.nEndPos = nEnd; *SWv*sD  
nThreadID = id; ;>sq_4_  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 []!tT-Gzy  
} 4U:DJ_GN  
WtMcI>4w  
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public void run() v#w4{.8)  
{ N{|[R   
while(nStartPos < nEndPos && !bStop) g\E ._ab<  
{ f.sPE8#3=  
0GF%~6  
s8C:QC  
try{ UX03"gX  
URL url = new URL(sURL); *pmoLiuB>  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 9.^-us1  
httpConnection.setRequestProperty("User-Agent","NetFox"); U. NeK{  
String sProperty = "bytes="+nStartPos+"-"; MI?]8+l  
httpConnection.setRequestProperty("RANGE",sProperty); nvw NjN  
Utility.log(sProperty); yZQ1] '^31  
u)wu=z8  
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InputStream input = httpConnection.getInputStream(); 1i ?gvzrq  
//logResponseHead(httpConnection);  j@s=ER  
3~#ZE;>#  
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byte[] b = new byte[1024]; "~B~{ _<j  
int nRead; ^Jc$BMaVg  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) &?&'"c{;m  
{ MAl{66  
nStartPos += fileAccessI.write(b,0,nRead); 3ZLr"O1l)  
//if(nThreadID == 1)  zgZi  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); PpI+@:p[  
} K#%O3RRs  
qFB9,cUqh  
b6 J2*;XG  
Utility.log("Thread " + nThreadID + " is over!"); Tey,N^=ek  
bDownOver = true; Q5T(;u6  
//nPos = fileAccessI.write (b,0,nRead); 3(>(lk  
} `kI?Af*;v  
catch(Exception e){e.printStackTrace ();} Djg1Qh  
} `\4RFr$  
} btJ,dpir  
N4
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ayB=|*Q"  
//打印回应的头信息 >^2ZM  
public void logResponseHead(HttpURLConnection con) e/g<<f-  
{ Nn~tb2\vk  
for(int i=1;;i++) `HMligT  
{ &6=TtTp"9  
String header=con.getHeaderFieldKey(i); Q%_!xQP`  
if(header!=null) g^Ugl=f,  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); /S-/SF:>g  
Utility.log(header+" : "+con.getHeaderField(header)); %`t]FV^#  
else *rujdQ
f  
break; $_%2D3-;D  
} 'US8"83  
} QH~8 aE_i  
~)oWSo5ll  
b6rzHnl{  
public void splitterStop() HXlr  
{ 7M&.UzIY`  
bStop = true; a,F8+ Pb>  
} 8Iqk%n~(  
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} ,4h!"c  
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/* a!S
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**FileAccess.java %BT)oH}  
*//文件访问(定位，写) QBN=l\m+  
package NetFox; 0e7O#-  
import java.io.*;  h;:Se  
@eAGN|C5  
;'Z,[a  
public class FileAccessI implements Serializable{ jSOa   
q_%w l5\F  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 \6nQ-S_  
RandomAccessFile oSavedFile; wnZ*k(  
long nPos; Xm0&U?dZB  
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public FileAccessI() throws IOException 4`EvEv$i  
{ GT1 X  
this("",0); !<['iM  
} ||"":K  
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public FileAccessI(String sName,long nPos) throws IOException pXh^M{.  
{ :*w:eKk  
oSavedFile = new RandomAccessFile(sName,"rw"); `,8R~-GPD  
this.nPos = nPos; p0:&7,+a,  
oSavedFile.seek(nPos); JXZ:Wg  
} %3@RZe  
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:Z7"c`6L!~  
public synchronized int write(byte[] b,int nStart,int nLen) ~$TE  
{ gw}7%U`T9  
int n = -1; zN729wK  
try{ {) '" k6w  
oSavedFile.write(b,nStart,nLen); jT wM<?  
n = nLen;
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} <|>:UGAR  
catch(IOException e) '8kL1  
{ aS1P]&  
e.printStackTrace (); >x_:=%Wr+  
} G3^n_]Jb  
2=UTH%1D  
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return n; /i]=ndAk  
} MlcoOi!  
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} -$!Pf$l@  
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7+2aG  
/* *F4G qX3  
**SiteInfoBean.java +XaO?F[c  
*/  _c7  
package NetFox; kdueQ(\  
s"^YW+HMb  
(/rIodHJO  
public class SiteInfoBean { 3 v,ae7$U&  
F" #3s=  
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private String sSiteURL; //Site's URL vng8{Mx90*  
private String sFilePath; //Saved File's Path >=q!!'$:  
private String sFileName; //Saved File's Name 6[Pr<4J  
private int nSplitter; //Count of Splited Downloading File %_X[{(  
%~v76;H<  
bMK'J  
public SiteInfoBean() MdTd$ 4J3  
{//nSplitter的缺省值为5 )*QTxN  
//default value of nSplitter is 5  "lnk  
this("","","",5); Zn=JmZ  
} `a1R "A  
q'8@0FT0  
rQ
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) #}]il0d  
{ 3E2.v5*  
sSiteURL= sURL; fB ,!|u  
sFilePath = sPath; Tk@g9\6O9  
sFileName = sName; {CyPcD'$s  
this.nSplitter = nSpiltter; C?<XtIoB  
}JTgj  
:@4>}k*  
} 2W-NCE%K)T  
^}pREe c=  

>A@D;vx  
public String getSSiteURL() >~bj7M6t  
{ gZ%O<XO  
return sSiteURL; z(#hL-{c  
} #,9TJ:~N  
7J_f/st  
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public void setSSiteURL(String value) j!8+|eAkk  
{ {,mRMDEy  
sSiteURL = value; v}*u[GWl]  
} N)I T?  
PHL@1K{)  
CzsY=DBH=  
public String getSFilePath() >yHnz?bf@  
{ !?-5hh1\  
return sFilePath; r#Oz0=0u  
} DO,&Foh\  
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>mDubP  
public void setSFilePath(String value) s/&]gj"  
{ &^D@(m7>{K  
sFilePath = value; ~E|V{z%  
} G78j$ ^/0  
EYD{8Fw-  
fvfVBk#  
public String getSFileName() o 0 #]EMr  
{ .Qw@H#dtW  
return sFileName; -$|X\#R  
} R3!vS+5rR  
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public void setSFileName(String value) aZCT|M1  
{ pC.T)k  
sFileName = value; : )*Ge3  
} m-FDCiN>  
&B,& *Lp  
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public int getNSplitter() 7?WBzo!!L  
{ /g7?,/vnZ  
return nSplitter; k_^/  
} *

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{hP&P  
2/q=l
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public void setNSplitter(int nCount) 0!\q
  
{ ]c=1-Rl
  
nSplitter = nCount; 0BD((oNg  
} (SVr>|Db  
} 9+Hb`  
~*]`XL.-  
tBUQf*B  
/* t"vO&
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**Utility.java Z6@J-<u  
*/ 'yjH~F.  
package NetFox; !#s7 F  
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public class Utility { g'7hc~=  
{ 4{{;   
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public Utility() ]7 mSM  
{ B;je|M!d  
)#B
fd(F  
,w>?N\w!}  
} JLn<,Gn)<\  
%"fKZ  
//线程睡眠 *9wHH-#  
public static void sleep(int nSecond) U {!{5l:  
{ ^}\R]})w"  
try{ ]arskmB]  
Thread.sleep(nSecond); s4k%ty}  
} @&yj7-]  
catch(Exception e) ebK wCZwK*  
{ agD.J)v\  
e.printStackTrace (); MCG~{#`  
} Q kpmPQK  
} =)5a=^ 6  
>iJuR.:OO  
//日志 i_ TdI  
public static void log(String sMsg) [i#Gqx>'w  
{ 8QBL:7<  
System.err.println(sMsg); MoHvXp;X  
} ') y~d  
)KQum`pO  
~riw7"  
public static void log(int sMsg) Ih"Ol(W  
{ - Sgp,"a  
System.err.println(sMsg); rcT<OiYuig  
} Z`t?kXDNoI  
} 1=.kH[R  
6LQO>k  
ZfikNQU9r  
/* C;>Ll~f_  
**TestMethod.java <Rt@z|Zv  
*/ _3[BS9  
package NetFox; 6s2g+[  
Ma#-'J  
m/Z_HER^  
public class TestMethod { 5C?1`-&65V  
:h~!#;w_  
<2d@\"AoHE  
public TestMethod() Ij_`=w<  
{ ///xx/weblogic60b2_win.exe 3zHiu*2/!  
try{ fTgN2U  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 'YZs6rcJ  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); [G/X  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 3Gv i!h7  
fileFetch.start(); &X(-C9'j  
} ro@BmRMW  
catch(Exception e){e.printStackTrace ();}  Z.JTq~`I  
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/d'u1FnA=  
} s&</zU'  
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:  
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public static void main(String[] args) UMaKvr-C&  
{ KW<CU'  
new TestMethod(); Um<vs
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} -Ma"V  
} tEs$+b  
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