http断点续传简单实现（java)

/* 2/^3WY1U  
**SiteFileFetch.java Yj49
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*/ qyTU8Wp  
package NetFox; 03Ycf'W  
import java.io.*; (L&d!$,Dv  
import java.net.*; bI1N@
=  
{!L~@r  
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public class SiteFileFetch extends Thread { :5<UkN)R(  
#;yZ  
#;e:A8IQ  
SiteInfoBean siteInfoBean = null; //文件信息Bean 6bC3O4Rw  
long[] nStartPos; //开始位置 x 9fip-  
long[] nEndPos; //结束位置  }my`K  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 S,UDezxg  
long nFileLength; //文件长度 v!5 `|\  
boolean bFirst = true; //是否第一次取文件 a1lh-2xX  
boolean bStop = false; //停止标志 q0vQa  
File tmpFile; //文件下载的临时信息 u6JM]kR
  
DataOutputStream output; //输出到文件的输出流 V)25$aKW7  
}Sv:`9=  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） Y$_B1_  
public SiteFileFetch(SiteInfoBean bean) throws IOException #\OA)`U  
{ ~f98#43  
siteInfoBean = bean; aW7^d'ZZ\  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 8l`*]1.W<  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); f]CXu3w(J  
if(tmpFile.exists ()) h:|qC`}  
{ wmLs/:~  
bFirst = false; YS0<qSN
  
read_nPos(); } q8ASYNc  
} 4tBYR9|  
else =7eV/3  
{ "chDg(jMZ  
nStartPos = new long[bean.getNSplitter()]; Wne@<+mX  
nEndPos = new long[bean.getNSplitter()]; f-Z/tfC  
} {`@G+JV~Jw  
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/\n-P'}  
} j\M?~=*w  
iH@UTE;  
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public void run() '`Hr}  
{ x.$FNt(9  
//获得文件长度 <LiPEo.R  
//分割文件 +M/%+l  
//实例FileSplitterFetch f@!.mDm]  
//启动FileSplitterFetch线程 \9T7A&  
//等待子线程返回 P*j|.63  
try{ 6'f;-2  
if(bFirst) #H~64/  
{ mC#>33{  
nFileLength = getFileSize(); 0g8NHkM:2a  
if(nFileLength == -1) `ERz\`d~Y;  
{ M_DwUS1?  
System.err.println("File Length is not known!"); +NUG  
} abVmkdP_s  
else if(nFileLength == -2) eHUOU>&P]  
{ kAUymds;O  
System.err.println("File is not access!"); f!X[c?Xy"  
} ~P-mC@C  
else CrTw@AW9)  
{ 4Z0]oIX  
for(int i=0;i<nStartPos.length;i++) G3T]`Atf  
{ /)O"l@ }U  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ~k5W@`"W  
} a%0EiU  
for(int i=0;i<nEndPos.length-1;i++) QMm%@zH  
{ [$UI8tV  
nEndPos = nStartPos[i+1]; dM@1l1h/  
} J{G?-+`  
nEndPos[nEndPos.length-1] = nFileLength; C0Z=~Q%  
} d<Tc7vg4|U  
} {'H(g[k  
]ZS OM\}  
mt.))#1  
//启动子线程 Y'X%Aw;`  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; T)_hpt.  
for(int i=0;i<nStartPos.length;i++) >H,*H;6  
{ owv[M6lbD  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), H\[W/"  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), wMN]~|z>  
nStartPos,nEndPos,i); |_U= z;Y  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); >9J:Uo1z  
fileSplitterFetch.start(); Tlr v={  
} l'E6CL}@[  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), .=; ;  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); xT2PyI_:  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 9>#6*/Oa7  
nEndPos = " + nFileLength); K*dCc}:`  
// fileSplitterFetch[nPos.length-1].start(); \|[;Z"4l  
G3
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>yDZ
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//等待子线程结束 Y_P!B^z3  
//int count = 0; _)-o1`*-  
//是否结束while循环 mX|ojZ  
boolean breakWhile = false; q5S9C%b  
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while(!bStop) I%Z  
{ Dvln/SBk  
write_nPos(); 69.NPy@  
Utility.sleep(500); TD_Oo-+\  
breakWhile = true; <#HYqR',  
hE-M$LmN@  
/qw.p#  
for(int i=0;i<nStartPos.length;i++) QS`]  
{ 1h5 Akq  
if(!fileSplitterFetch.bDownOver) 4B][S'f  
{ P!k{u^$L  
breakWhile = false; 5@W j>:w  
break; kG*~|ma  
} NGWxN8P6  
} |wj?ed$ f  
if(breakWhile) +ck}l2&#  
break; FN73+-:n:j  
i}?>g-(  
QmIBaMI#  
//count++; 1BEHw?dLU  
//if(count>4) E_LN]v  
// siteStop(); I2Yz#V<%ru  
} 4KrL{Z+}  
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3+bt~J0  
System.err.println("文件下载结束！"); D1;QC  
} t#"Grk8Mz&  
catch(Exception e){e.printStackTrace ();} {l>hMxij  
} <54 S  
Y6d@h? ht  
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//获得文件长度 ,Y48[_ymm  
public long getFileSize() Du){rVY^d  
{ Lj;2\]
 
int nFileLength = -1; `9.r`&T6K  
try{ H>@+om  
URL url = new URL(siteInfoBean.getSSiteURL()); t |oR7qa{w  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); CJI~_3+K  
httpConnection.setRequestProperty("User-Agent","NetFox"); W@!S%Y9  
,7b[!#?8  
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int responseCode=httpConnection.getResponseCode(); 4E?Oky#}-  
if(responseCode>=400) 3f;>" P}  
{ S21,VpW\  
processErrorCode(responseCode); FxtI"g\0  
return -2; //-2 represent access is error POR\e|hRT]  
} VLN_w$iEq  
Xn\jO>[Ef  
#R RRu2  
String sHeader; :eLVC7'  
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for(int i=1;;i++) {[>Kob1  
{ s"?3]P  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); sn>~O4"  
//Utility.log(in.readLine()); Ecx
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sHeader=httpConnection.getHeaderFieldKey(i); WMP,\=6k0  
if(sHeader!=null) kO-(~];  
{ ^zgo#J5O  
if(sHeader.equals("Content-Length")) /H+a0`/  
{ 7v_8_K  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); M& CqSd  
break; \5cpFj5%  
} }4S6Xe  
} ;6hOx(>`=  
else 2)~>
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break; 1@=po)Hnp  
} '[O;zJN;  
} uRe'%?W  
catch(IOException e){e.printStackTrace ();} y18Y:)DkL  
catch(Exception e){e.printStackTrace ();} &G$Ucc `  
9]@!S|1  
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Utility.log(nFileLength); /,Jqmm#s^  
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.w,q0<}  
return nFileLength; ?[>3QE  
} 9Lfv^V0  
5nVt[Puw  
/vb`H>P  
//保存下载信息（文件指针位置） -s'-eQF J  
private void write_nPos() ?Pc'C  
{ pFz`}?c0  
try{ 8sK9G` k  
output = new DataOutputStream(new FileOutputStream(tmpFile)); e<q?e}>?  
output.writeInt(nStartPos.length); {cw /!B  
for(int i=0;i<nStartPos.length;i++) q6X1P"%.  
{ #yvGK:F  
// output.writeLong(nPos); eQvg7aO;  
output.writeLong(fileSplitterFetch.nStartPos); _n\GNUA  
output.writeLong(fileSplitterFetch.nEndPos); 5QO9Q]I#_\  
} ~.lPEA %%  
output.close(); xA[mm  
} Q.c\/&  
catch(IOException e){e.printStackTrace ();} m9}P9?  
catch(Exception e){e.printStackTrace ();} {T~#?v(  
} -RK- Fu<e  
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//读取保存的下载信息（文件指针位置） Pd]|:W< E  
private void read_nPos() ?5 [=(\/.  
{ W'u>#  
try{ 0Z]!/AsC  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); CQDkFQq-dq  
int nCount = input.readInt(); -1ub^f
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nStartPos = new long[nCount]; *bpD`s @  
nEndPos = new long[nCount]; 6/dI6C!  
for(int i=0;i<nStartPos.length;i++) Tkgs]q79  
{ IRqy%@)  
nStartPos = input.readLong(); 42ivT_H  
nEndPos = input.readLong(); iM3V=&)  
} i8HTzv"J  
input.close(); 8Kk(8a&v  
} DrK{}uM  
catch(IOException e){e.printStackTrace ();} 8BNi1Qn$  
catch(Exception e){e.printStackTrace ();} I ?.^ho  
} LvYB7<zk>  
m/EFHS49  
4#hSJ(~7S  
private void processErrorCode(int nErrorCode) cDkf qcC  
{ V,N%;iB}  
System.err.println("Error Code : " + nErrorCode); t}tEvh  
} `&6dnSC},P  
K8Y=S12Ti  
4)o  
//停止文件下载 h;NYdX5  
public void siteStop() @bP)406p  
{ i,9)\1R  
bStop = true; 7EO_5/cY  
for(int i=0;i<nStartPos.length;i++) cq4Ipe  
fileSplitterFetch.splitterStop(); 6<(
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=+d?x56  
 | (_  
} HT1!5
 
} A1zjPG&]  
//负责部分文件的抓取 Bo%NFB;  
**FileSplitterFetch.java ]~hk6kS8Q  
*/ !0mI;~q|F  
package NetFox;  U}j0
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import java.io.*; ))'<_nD  
import java.net.*; ~zNAbaC+>t  
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public class FileSplitterFetch extends Thread { fkNbS  
~Vjl7G\7i  
m$T-s|SY  
String sURL; //File URL &H:(z4/  
long nStartPos; //File Snippet Start Position 3n}?bY8@5_  
long nEndPos; //File Snippet End Position yd
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int nThreadID; //Thread's ID 'u<juFr  
boolean bDownOver = false; //Downing is over y;@:ulv[  
boolean bStop = false; //Stop identical "o}+Ciul  
FileAccessI fileAccessI = null; //File Access interface
=P #]  
3 xp)a%=7  
pr UM-u8  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException  t[ C/  
{ x>`%DwoRI  
this.sURL = sURL; (mtk 4  
this.nStartPos = nStart; _MX>#!l  
this.nEndPos = nEnd; .];=Pu^  
nThreadID = id; (n9gkO&8"  
fileAccessI = new FileAccessI(sName,nStartPos);//定位
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} HJYScwjQ;`  
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Z
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public void run() !^Y(^RS@  
{ 6MdiY1Lr!K  
while(nStartPos < nEndPos && !bStop) agW@{c  
{ ysf~|r4s  
W'+:'_{j:  
2Dj%,gaR  
try{ :@A9](gI  
URL url = new URL(sURL); _8UDT^?8,  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); u.Tcg^v  
httpConnection.setRequestProperty("User-Agent","NetFox"); v^iL5y!  
String sProperty = "bytes="+nStartPos+"-"; yFlm[K5YD  
httpConnection.setRequestProperty("RANGE",sProperty); a]tVd#  
Utility.log(sProperty); Px`!A EFd[  
Q9G;V]./  
xLH)P<^`C  
InputStream input = httpConnection.getInputStream(); CooQ>f  
//logResponseHead(httpConnection); Jidwt$1l(  
eb"5-0  
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byte[] b = new byte[1024]; ptxbDzOz  
int nRead; JKGe"  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Jd^,]  
{ GKc`xIQ  
nStartPos += fileAccessI.write(b,0,nRead); gz#i.-  
//if(nThreadID == 1) q2:6QM&  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); }"!I[Ek> y  
} q\p:X"j|  
tQYM&6g  
+@k+2?] FO  
Utility.log("Thread " + nThreadID + " is over!"); eu|;eP-+d  
bDownOver = true; 6wECo  
//nPos = fileAccessI.write (b,0,nRead); !.(P~j][  
} T&o(N3lW  
catch(Exception e){e.printStackTrace ();} G.dTvLv  
} /?F/9hL  
} !AfHk|  
@;?p&.W`D  
0eu$ W  
//打印回应的头信息 iaE^a^*
 
public void logResponseHead(HttpURLConnection con) H{?vbqQ  
{ ktBj|-'>  
for(int i=1;;i++) YRN06*hS  
{ v+#}rUTF  
String header=con.getHeaderFieldKey(i); 7f!YoW;1  
if(header!=null) ^mO~W!"  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); |My4SoOF  
Utility.log(header+" : "+con.getHeaderField(header)); \k!{uRy'  
else !SdSE^lz`  
break; E+g@M8D  
} E3gh?6  
} Tl
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9}F*P669f  
e:n<EnT  
public void splitterStop() T@&K-UQ  
{ Rww{:R  
bStop = true; d,Yw5$i  
} P&ptJtNg  
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B s#hr3h-  
} yS(fILV  
8sM|%<$=j  
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/* l@+7:n4K0  
**FileAccess.java JJ2_hVU  
*//文件访问(定位，写) sjwo/+2  
package NetFox; 9s$CA4?HP  
import java.io.*; Xi,CV[L\  
![_*(8v}S  
hp7|m0.JW  
public class FileAccessI implements Serializable{ ';jYO
Ve  

,\  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 EGzzHIZ`!  
RandomAccessFile oSavedFile; 1o;J,dYu  
long nPos; xLWwYK  
$oU*9}}Rn  
b TM{l.Aq3  
public FileAccessI() throws IOException EwC{R`  
{ -
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this("",0); #W'HR
 
} A1D^a,  
LO khjHR  
{/(D$"j(S  
public FileAccessI(String sName,long nPos) throws IOException n%C>E.Tq  
{ M&@b><B  
oSavedFile = new RandomAccessFile(sName,"rw"); ^*8G8'k;$  
this.nPos = nPos; )d1_Wm#B  
oSavedFile.seek(nPos); 1V4s<m>#  
} zHL@i0>^  
D!NQ~'.a=2  
,dov<U[ia  
public synchronized int write(byte[] b,int nStart,int nLen) D2!X?"[P  
{ XY)&}u.  
int n = -1; =;3Sx::=  
try{ t2"O  
oSavedFile.write(b,nStart,nLen); Hh-+/sO~"  
n = nLen; 9S7kUl{  
} h[1MtmNw  
catch(IOException e) v'qG26
  
{ =Z+nz^'b  
e.printStackTrace (); 5b/|!{  
} ?ROqn6k&c  
^G.Xc\^w:  
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return n; WZ7BoDa7O  
} ,TPISs  
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an
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} 65p?Igb  
#H{<gjs]  
( Qcp{
q  
/* ~ ! 3I2  
**SiteInfoBean.java " '6;/N  
*/ .0iQad&duh  
package NetFox; U.XNv-M  
e~@[18  
'fF;(?  
public class SiteInfoBean { a /#PLP  
S<u-n8bv  
=p?WBZT|:  
private String sSiteURL; //Site's URL 4EZ9hA9+  
private String sFilePath; //Saved File's Path n9A7K$ZD@  
private String sFileName; //Saved File's Name bQP{|  
private int nSplitter; //Count of Splited Downloading File -
>O2I?  
W#BM(I  
x~{;TZa[I  
public SiteInfoBean() 5ish\"  
{//nSplitter的缺省值为5 <]4i`6{v  
//default value of nSplitter is 5 ;F#7Px(q  
this("","","",5); ?)[EO(D  
} T2Y,U {  
1Q4}'0U4  
$
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 1jPJw3"3h  
{ &S
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sSiteURL= sURL; =ng\ 9y[;D  
sFilePath = sPath; bH2MdU  
sFileName = sName; 8<7GdCME  
this.nSplitter = nSpiltter; YoLx>8  
D3^7y.u<)  
'XofD}dm  
} I_%a{$Gjl  
4*mS y  
6{+{lBm=y  
public String getSSiteURL() t" 7yNs(I  
{ 'd
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return sSiteURL; \nB8WSvk2W  
} 4jBC9b}O  
|t)}VM%
 
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public void setSSiteURL(String value) T?1Du"d8  
{ lGk{LO)  
sSiteURL = value; pY~,(s|Qb  
} b0A1hb[|  
qY$qaM^=  
*B\H-lp?  
public String getSFilePath() f{i8w!O"~  
{ ofMY,~w  
return sFilePath; U uM$~qf/K  
}
;)I'WQ]Q  
NeBsv= [-  
jhX[fT1m  
public void setSFilePath(String value) N!x =eC  
{ )r z+'|,  
sFilePath = value; *"98L+  
} >,gvb5  
=rQP[ICs!  
-}4NT{E  
public String getSFileName() pge++Di  
{ ELjK0pE}-  
return sFileName; #D9e$E(J^  
} 2gjGeM  
zrv#Xa!O\  
^6P3%  
public void setSFileName(String value) 6ubL1K  
{ fr}Eaa-{^  
sFileName = value; X_G| hx  
} j:&4-K};Z`  
'K*AV7>E  
(?kl$~&|  
public int getNSplitter() |Uk" {  
{ q;D+ai  
return nSplitter; xc:!cA{V  
} N+)?$[  
,prF6*g+WE  
0\~Z5k`IT  
public void setNSplitter(int nCount) q
)lnS )  
{ FvuGup`w  
nSplitter = nCount; $1zvgep  
} 4E[!,zvl  
} LrV{j?2@  
mNAY%Wn6k  
9 ASb>A2~  
/* #4h+j%y[H  
**Utility.java $BDBN_p  
*/ $W42vjr4  
package NetFox; C#=bW'C  
]$ b<Gs  
vhT_=:x  
public class Utility { \mN[gT}LHm  
y3;q_4.  
5Wj; [2 )  
public Utility() %T=A{<[`  
{ +P`(Rf"luu  
\#x}q'BC4  
V*$L;xbC|  
} 9>#:/g/  
rf9_eP  
//线程睡眠 pA#}-S%  
public static void sleep(int nSecond) (|fm6$  
{  <n\`d  
try{ )g@S%Yu  
Thread.sleep(nSecond); l0Ti Z  
} a!c[!  
catch(Exception e) v !Kw< fp|  
{ 1fL<&G  
e.printStackTrace (); tAFti+Qb  
} &~f3psA  
} FM5e+$>@  
ql&*6KZ"  
//日志 [rOaM$3|  
public static void log(String sMsg) zN_:nY>
  
{ mN5 8r"!J  
System.err.println(sMsg); t.hm9}UQ  
} 68'>Zbelb  
7C?.L70ZY  
3%<C<(  
public static void log(int sMsg) MuEy>dl  
{ TE-;X,gDV_  
System.err.println(sMsg); )I@L+  
} $H'X V"<o  
} %YlTF\-  
MYnH2w]  
VnJMmMM  
/* "x&C5l}n  
**TestMethod.java z&3]%t `C  
*/ 1(GHCxA8G  
package NetFox; ^yKY'>T#d  
AzpV4(:an.  
$ 'QdFkOr  
public class TestMethod { ]&i+!$N_  
[{<dbW\ 9  
6a>H|"PNE  
public TestMethod() W*xX{$NL  
{ ///xx/weblogic60b2_win.exe >^"BEG9i:  
try{ jUjr6b"  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); M\+*P,i
 
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); I/COqU7~  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Hwe)T
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fileFetch.start(); s3lwu :4f  
} @#b0T:+v'  
catch(Exception e){e.printStackTrace ();} =z
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*R`MMm  
PG)_L.7rJ  
} K2/E#}/  
f!-Sz/c#  
'CS.p!Z\  
public static void main(String[] args) NyI;v=  
{ c! H 9yk  
new TestMethod(); r.FLGDU  
} m<3v)R[>  
} /k7wwZiY@  
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