http断点续传简单实现（java)

/* AT2nVakL  
**SiteFileFetch.java zN^n]N_?  
*/ +nJgl8'^y  
package NetFox; 2h5nMI]'  
import java.io.*; Hl{S]]z  
import java.net.*; iT2B'QI=<  
 J4fi'  
,[P{HrHx  
public class SiteFileFetch extends Thread { hpO`]  
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SiteInfoBean siteInfoBean = null; //文件信息Bean =A83W/4  
long[] nStartPos; //开始位置 pHLB= r  
long[] nEndPos; //结束位置 hEKf6#  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Z{]0jhUyNh  
long nFileLength; //文件长度 7$CBx/X50)  
boolean bFirst = true; //是否第一次取文件 HTX?,C_  
boolean bStop = false; //停止标志 Brf5dT49  
File tmpFile; //文件下载的临时信息 PoG-Rqe  
DataOutputStream output; //输出到文件的输出流 XAF+0 x!  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） < t,zaIi  
public SiteFileFetch(SiteInfoBean bean) throws IOException leTf&W  
{ W\d{a(*  
siteInfoBean = bean; =THpdtL  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); fSK]|"c  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ,(EO'T[  
if(tmpFile.exists ()) `p2+&&]S  
{ \hDlTp}  
bFirst = false; H4:`6 PSL  
read_nPos(); |}=acc/  
} _Xk.p_uh  
else -zOdU}91Ao  
{ bk;?9%TW  
nStartPos = new long[bean.getNSplitter()]; H[,i{dD  
nEndPos = new long[bean.getNSplitter()]; TQpfQ  
} |}BLF  
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} Qz5sxi  
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public void run() 4|riKo)  
{ E8$20Ue  
//获得文件长度 /Z'L^L
%R  
//分割文件 K|zZS%?$  
//实例FileSplitterFetch 6jE|  
//启动FileSplitterFetch线程 &Sw%<N*r  
//等待子线程返回 u0|8Tgf  
try{ }B\a<0L/  
if(bFirst) X' H[7 ^W  
{ RJ 8+h  
nFileLength = getFileSize(); dCi?SIN  
if(nFileLength == -1) $'BSH4~|.  
{ Dfg2`l  
System.err.println("File Length is not known!"); X[]m _@v  
} 6Ypc`  
else if(nFileLength == -2) Ql/cN%^j$  
{ v$7QIl_/7  
System.err.println("File is not access!"); Mm.
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} _aGOb;h  
else WA)yfo0A  
{ l?Udn0F  
for(int i=0;i<nStartPos.length;i++) vK|E>nL  
{ 8@i7pBl@  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); xjfV?B'Y}V  
} Qu?R8+"KS  
for(int i=0;i<nEndPos.length-1;i++) ]m g)Q:d,  
{ _}lZ,L(w  
nEndPos = nStartPos[i+1]; qE&v ;  
} YVQN&|-  
nEndPos[nEndPos.length-1] = nFileLength; PRu 6xsyA  
} .7e2YI,S  
} #hfXZVD  
\KMToN&2  
!=;+%C&8y  
//启动子线程 @$S+Ne[<  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; S%bCyK%p  
for(int i=0;i<nStartPos.length;i++) & ?h#Z!  
{ s.bc>E0  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 27 ]':A4_  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), TS
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nStartPos,nEndPos,i); ]zj9A]i:a  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); R "n5  
fileSplitterFetch.start(); ^U `[(kz=  
} Ixb=L(V  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 2|3)S`WZl  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); RQ vft  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", i6dHrx]:,  
nEndPos = " + nFileLength); "+kL)]  
// fileSplitterFetch[nPos.length-1].start(); fkuLj%R  
ii[F]sR\  
qkt0**\  
//等待子线程结束 Y2a5bc P  
//int count = 0; zKw`Md  
//是否结束while循环 .aO,8M  
boolean breakWhile = false; u$DHVRrF<  
Wvbf"h
q  
kpJ@M%46  
while(!bStop) UtPLIal  
{ !}YAdZJ  
write_nPos(); %`>nS@1zp  
Utility.sleep(500); ?I6fye7  
breakWhile = true; ?k]2*}bz  
>zw.GwN|  
5b*M*e&=C  
for(int i=0;i<nStartPos.length;i++) K
{&mI/;  
{ nxUJN1b!N  
if(!fileSplitterFetch.bDownOver) _-q.Q^  
{ pWy=W&0~qf  
breakWhile = false; YLqGRE`W  
break; $bW3_rl%X  
} f\]sz?KY  
} _,p/l&<  
if(breakWhile) $+P>~X)  
break; ?oV
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M2 ,YsHt  
%-)H^i~]%  
//count++; )2Wi`ZT  
//if(count>4) 7|{}\w(I  
// siteStop(); ;nep5!s;<  
} "fG8?
)d;  
n!YKz"$  
!TA

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System.err.println("文件下载结束！"); f%SZg!+t  
} PPb7%2r  
catch(Exception e){e.printStackTrace ();} D?;"9e%  
} 5Sm}nH  
a][f  
.:@Ykdm4I  
//获得文件长度 fKeT
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public long getFileSize() GGNvu)"  
{ BzkooJ  
int nFileLength = -1; 8K.R=  
try{ aoTM  
URL url = new URL(siteInfoBean.getSSiteURL()); dYT%  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); SQ44  
httpConnection.setRequestProperty("User-Agent","NetFox"); ^Y=\#-Dd  
k3u"A_"c  
F20E_2;@@  
int responseCode=httpConnection.getResponseCode(); [<2<Y  
if(responseCode>=400) P^A!.}d  
{ FG%X~L<d,)  
processErrorCode(responseCode); ?ATOXy  
return -2; //-2 represent access is error W}m)cn3@  
} Lhl]g^SN  
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0+?7EL~  
String sHeader; h}*/Ge]aM  
/j4P9y^]=  
".W8)  
for(int i=1;;i++) )k\H@Dy%$  
{ +1uF !G&l  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); KV}FZ3jY  
//Utility.log(in.readLine()); U7K,AflK?M  
sHeader=httpConnection.getHeaderFieldKey(i); m+b):  
if(sHeader!=null) ?%O(mC]u&  
{ '?!zG{x  
if(sHeader.equals("Content-Length")) ~k!j+>yT  
{ !ipR$ dM  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); \?Z{hmN  
break; Q3 u8bx|E  
} !j:9`XD|  
} ,I7E[LU
  
else 2/?`J  
break; mR&H9NG  
} *C5R}9O5  
} ;1:Js0=;H  
catch(IOException e){e.printStackTrace ();} <D:.(AUeO  
catch(Exception e){e.printStackTrace ();} ,VCyG:dw  
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{1IfU  
Utility.log(nFileLength); 5k`l$mW{  
%6t2ohO"  
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return nFileLength; Z)! qW?  
} G!"YpYml  
QIB\AAclO  
]QpWih00V  
//保存下载信息（文件指针位置） I/&%]"[^u  
private void write_nPos() E8pB;\Z(  
{ 6{"$nF]  
try{ "/3 db[  
output = new DataOutputStream(new FileOutputStream(tmpFile)); vK9E   
output.writeInt(nStartPos.length); *G{^|z  
for(int i=0;i<nStartPos.length;i++) ePr&!Tz#  
{ C"!gZ8*\!9  
// output.writeLong(nPos); pk^K:Xs}  
output.writeLong(fileSplitterFetch.nStartPos); CS@FYO  
output.writeLong(fileSplitterFetch.nEndPos); {_`^R>"\&w  
} 23c 8  
output.close(); =-8bsV/l  
} ;LG#.~f  
catch(IOException e){e.printStackTrace ();} *QwY]j%^  
catch(Exception e){e.printStackTrace ();} uW30ep'  
} .$qnZWcgG  
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//读取保存的下载信息（文件指针位置） U&Wt%U{  
private void read_nPos() p^Ak1qm~e  
{ jFA
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try{ S<VSn}vn  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); <J`0mVOX  
int nCount = input.readInt(); g'H$R~ag  
nStartPos = new long[nCount]; G_0(
|%  
nEndPos = new long[nCount]; n;@bLJ$W  
for(int i=0;i<nStartPos.length;i++) fDT%!  
{ W8ouO+wK  
nStartPos = input.readLong(); `-(|>5wWS  
nEndPos = input.readLong(); =T(6#"  
} Ove<mFI\  
input.close(); l|/ep:x8  
} P!H_1RwXKC  
catch(IOException e){e.printStackTrace ();} *1v[kWa?  
catch(Exception e){e.printStackTrace ();} q=%RDG+  
} 9;r)#3Q[^  
/W>iJfx  
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private void processErrorCode(int nErrorCode) PmKeF}  
{ P(H8[,  
System.err.println("Error Code : " + nErrorCode); PcA2/!a  
} )TVFtI=,NN  
v.pBX<  
tnPv70m  
//停止文件下载 j6Yy6X]  
public void siteStop() t=Xv;=daB  
{ SZ,YS 4M  
bStop = true; |y0(Q V  
for(int i=0;i<nStartPos.length;i++) CDP U\ZG  
fileSplitterFetch.splitterStop(); {OXFN;2  
,q}MLTSi  
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} \6R,Nq
 
} w8MG(Lq1"  
//负责部分文件的抓取 t.7?  
**FileSplitterFetch.java \/: {)T~  
*/ k< y>)  
package NetFox; \.-}adKg  
.NYbi@bk(<  
-I&m:A$4*  
import java.io.*; )%`^xR  
import java.net.*; D|e uX7b  
k@/sn(x  
fh](K'P#^  
public class FileSplitterFetch extends Thread { ,.kha8v  
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ti I.W  
String sURL; //File URL >8k_n  
long nStartPos; //File Snippet Start Position GBRa.;Kk  
long nEndPos; //File Snippet End Position /atW8 `&  
int nThreadID; //Thread's ID Q36qIq_0e  
boolean bDownOver = false; //Downing is over V:VO[e<e  
boolean bStop = false; //Stop identical ~GL]wF2#  
FileAccessI fileAccessI = null; //File Access interface G LIi6  
aqj@Cjk4Z  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException (NF~Ck$#q  
{ _3TY,l~  
this.sURL = sURL; )N7Y^CN~  
this.nStartPos = nStart; Qa-K$dm%  
this.nEndPos = nEnd; sj HrPs e  
nThreadID = id; I'uSp-Sfy  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 mt,OniU=Q  
} M<kj_.  
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hRUhX[  
public void run() {(r`k;fB  
{ 6)Y.7XR  
while(nStartPos < nEndPos && !bStop) -OapVac  
{ ;#vKi0V7  

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try{ \$*7 >`k  
URL url = new URL(sURL); ]x(e&fyHB  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 5N/%v&1  
httpConnection.setRequestProperty("User-Agent","NetFox"); D ,o}el
 
String sProperty = "bytes="+nStartPos+"-"; 5hQE4/hH  
httpConnection.setRequestProperty("RANGE",sProperty); PH+S};Uxv  
Utility.log(sProperty); B{'( L|  
g^}8:,F_  
{<R2UI5m5  
InputStream input = httpConnection.getInputStream(); 8,?h~prc  
//logResponseHead(httpConnection); {q`jDDM  
+yk24 `>  
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byte[] b = new byte[1024]; 6L"%e!be6  
int nRead; Z0Vl+  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Y]/%t{Y  
{ , udTvI  
nStartPos += fileAccessI.write(b,0,nRead); }bdmomV  
//if(nThreadID == 1) ?0v-qj+  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); NbgK@eV}+{  
} =a@j=  
x{n`^;Y1  
l5Gq|!2yxD  
Utility.log("Thread " + nThreadID + " is over!"); 4QvsBpz@  
bDownOver = true; eU".3`CtY  
//nPos = fileAccessI.write (b,0,nRead); 4KIRHnaj  
} '>cKH$nVC}  
catch(Exception e){e.printStackTrace ();} 95A1:A^t  
} Xq_5Qv  
} 2jR r,Nl  
/OLFcxEWh  
cx&>#8s&  
//打印回应的头信息 }o(zj=7  
public void logResponseHead(HttpURLConnection con) |=`~-i2W  
{ S|
7!{}  
for(int i=1;;i++) RS)tO0  
{ '98VYCL  
String header=con.getHeaderFieldKey(i); kEOS{C%6R  
if(header!=null) "B3N*R(["  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); JBE!j-F  
Utility.log(header+" : "+con.getHeaderField(header)); M>~Drul  
else `$,GzS(  
break; y9q8i(E0  
} LBM ^9W  
} :.Jf0  
+av@$}  
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public void splitterStop() _+K_5IO4  
{ >7I15U  
bStop = true; 1*'HL#  
} *>|gxM8  
+ +M$#Er&  
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} $8UUzk  
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/* vk77B(u  
**FileAccess.java O_wEcJPE  
*//文件访问(定位，写) OSs&r$  
package NetFox; :Av#j@#  
import java.io.*; ]s'Q_wh_-v  
q8/MMKCbX  
=G7m)!  
public class FileAccessI implements Serializable{ cq}EZ@ .  
}+.}J  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 =Je[c,&j$?  
RandomAccessFile oSavedFile; tnH2sHby  
long nPos; $*e2YQdLo  
B* ?]H*K  
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public FileAccessI() throws IOException Fq|Ni$  
{ z\K"Rg~J  
this("",0); yE:+Lo`>  
}
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&,zq%;-f  
public FileAccessI(String sName,long nPos) throws IOException kD=WO4}  
{ NW]Lj>0Y  
oSavedFile = new RandomAccessFile(sName,"rw"); o /j*d3  
this.nPos = nPos; )c8rz
[i  
oSavedFile.seek(nPos); fmU {  
} 8(pp2rlR  
1S{D6#bE  
J]{QB^?  
public synchronized int write(byte[] b,int nStart,int nLen) ]^h]t~  
{ T|nDTezr  
int n = -1; z@!`:'ak  
try{ "W6uV!  
oSavedFile.write(b,nStart,nLen); OLyf8&AU@  
n = nLen; gG0!C))8  
} BXtCSfY$  
catch(IOException e) 4Jp:x
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{ K"|l@Q[  
e.printStackTrace (); A)bWcB}U  
} Y<N5# );f  
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return n; uatm/o^~,  
} l4F%VR4KT  
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} g;pcZ9o
 
s'!Cp=xQF"  
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/* S0zD"T  
**SiteInfoBean.java ^uKwB;@  
*/
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package NetFox; wxK
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?qPo=~y01  
SheM|I~de  
public class SiteInfoBean { .B7,j%1r  
\H1(PA  
u_@f$  
private String sSiteURL; //Site's URL !hJ+Lp_  
private String sFilePath; //Saved File's Path 5eLtCsHz  
private String sFileName; //Saved File's Name $Q&lSVQ  
private int nSplitter; //Count of Splited Downloading File T1ut"
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4w*Skl=F}  
\:b3~%Fz  
public SiteInfoBean() XW[j!`nlk  
{//nSplitter的缺省值为5 `F-/QX[:  
//default value of nSplitter is 5 Oxm>c[R  
this("","","",5); LhA*F[6$M  
} (up~[  
w mn+  
%'bM){  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) /a{la8Ni  
{ * aN  
sSiteURL= sURL; ,k24w7K%d  
sFilePath = sPath; V3&RJ k=b  
sFileName = sName; ]] !VK  
this.nSplitter = nSpiltter; IdzxS  
v:IpMU-+\  
WffQ:L?  
} &-;4.op  
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xcd#&  
public String getSSiteURL() S=MEG+Ad  
{ ?:vv50  
return sSiteURL; RiDJ> 6S  
} .CL[_;}  
QA< Rhv,  
Z/W:97M  
public void setSSiteURL(String value) x3hB5p$q  
{ .!Oo|m`V@  
sSiteURL = value; R cAwrsd  
} h?AS{`.1  
DVG(Vw  
N:S/SZI  
public String getSFilePath() |z9*GY6RU  
{ M\o9I  
return sFilePath; ZT'`hK_up  
} M||+qd W!  
*{YlN}vA  
Bc(Y(X$PK  
public void setSFilePath(String value) 0]'7_vDs|  
{ \.0^n3y  
sFilePath = value; VU#`oJ:{  
} X.OD`.!>  
q8FTi^=Kb  
0pK=o"^?@  
public String getSFileName() T5R-B=YWu  
{ ;ic3).H  
return sFileName; |LRedD7n  
} 6^V=?~a&z  
pM+ AjPr  
2a-w% (K  
public void setSFileName(String value) )Lk639r  
{ QiQ_bB!\  
sFileName = value; B\=L3eL<D  
} UxbjA- U[  
6@Y_*4$|  
8hu<E4]L  
public int getNSplitter() Dl<bnx;0  
{ @D.}\(  
return nSplitter; lAS#874dE  
} 9Z|jxy  
rx'RSo#1O  
!`k1:@NZ  
public void setNSplitter(int nCount) _Us#\+]_:  
{ Z 8S\@I  
nSplitter = nCount; ?h3Y)5xT  
} 9{'N{  
} aAZZ8V  
a+[RS]le  
HU1h8E$-  
/* n
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**Utility.java <Q3oT  
*/ RU'=ERYC  
package NetFox; ?5+.`L9H  
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public class Utility { 6o!!=}'E[  
p09HL%~R  
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public Utility() X@'uy<tI-  
{ (lXGmx8  
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SAH-p*.  
} cpe+XvBuK  
ZXu>,Jy  
//线程睡眠 e|NG"
<  
public static void sleep(int nSecond) L(/e&J@><  
{ /1Qr#OJ(]  
try{ &VhroHO  
Thread.sleep(nSecond); z#8~iF1  
} p?{Xu4(  
catch(Exception e) g9m-TkNk  
{ T]R|qlZ  
e.printStackTrace (); 5/q}`T9i%7  
} cCSs  
} 5Iy|BRU(%  
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//日志 aKV$pC<[o  
public static void log(String sMsg) ;PF`Wj  
{ ynmWW^dg  
System.err.println(sMsg); <>n0arAn  
} >Y&N8PHD  
dah[:rP,n{  
mH54ja2  
public static void log(int sMsg) 5 z~1Dw  
{ __lM7LFL  
System.err.println(sMsg); ,oORW/0iS  
} d)B@x`  
} @*F"Q1 wI  
Vmc5IPd{\  
~9?cn  
/* Av @b!iw+  
**TestMethod.java Y_Eb'*PY  
*/ wGU*:k7p  
package NetFox; Hj'xAtx5  
_f
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R]Vt Y7}i,  
public class TestMethod { G !<Z.]  
~Xw"}S5  
-B>++r2A^  
public TestMethod() 214Ml0/%  
{ ///xx/weblogic60b2_win.exe ,ZKr.`B  
try{ D_?K"E=fw  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); }xKP~h'F  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ,368d9,rDz  
SiteFileFetch fileFetch = new SiteFileFetch(bean); fr,7rS/w{l  
fileFetch.start(); x"eRJii?  
} Xk:OL,c  
catch(Exception e){e.printStackTrace ();} _G_Cj{w  
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} TSA,WP\  
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public static void main(String[] args) ,c$,!.r  
{ rjl`&POqc  
new TestMethod(); 32l3vv.j  
} v.\*./-
i  
} -Btk 3  
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