http断点续传简单实现（java)

/* 5nK|0vv%2  
**SiteFileFetch.java r^Soqom3  
*/ @@}muW>;T  
package NetFox; K k^!P*#  
import java.io.*; G#='*vOtO  
import java.net.*; J+`gr_&  
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public class SiteFileFetch extends Thread { \\ZhM  
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SiteInfoBean siteInfoBean = null; //文件信息Bean y }h2
  
long[] nStartPos; //开始位置 YL[y3&K  
long[] nEndPos; //结束位置 <4^y7]]F  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 u%Z4 8wr  
long nFileLength; //文件长度 aZmbt,.V  
boolean bFirst = true; //是否第一次取文件 {q&A/  
boolean bStop = false; //停止标志 p4K 8L'nZ  
File tmpFile; //文件下载的临时信息 }@53*h i(  
DataOutputStream output; //输出到文件的输出流 VD{_
6  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ul"Z% 1]  
public SiteFileFetch(SiteInfoBean bean) throws IOException _b &Aa%  
{ ON"V`_dq+M  
siteInfoBean = bean; fJi?~[5<  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); t2qWB[r  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); :k~ p=ko  
if(tmpFile.exists ()) w!Z,3Yc)  
{ L)Da1<O  
bFirst = false; @2\UjEo~  
read_nPos(); ">nFzg?Y  
} 0JhUncx  
else /!y3ZzL  
{ Fd._D"  
nStartPos = new long[bean.getNSplitter()]; {[+Q\<  
nEndPos = new long[bean.getNSplitter()]; sB01QVx47  
} QFhQfn  
eXmYw^n  
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} ;=8@@9  
/jOug>s  
=[Tf9uQY  
public void run() <"S/M]9  
{ JZ-M<rcC  
//获得文件长度 > 'JWW*Y!  
//分割文件 k59.O~0V  
//实例FileSplitterFetch 6<UI%X  
//启动FileSplitterFetch线程 [wJl]i  
//等待子线程返回 QSOJHRl=C  
try{ .r@'9W^8  
if(bFirst) fXkemB^)_  
{ GU)NZ[e  
nFileLength = getFileSize(); Q\$cBSJC1  
if(nFileLength == -1) "C+Fl /v  
{ PmDar<m  
System.err.println("File Length is not known!"); |>nVp:t^  
} Zr;(a;QKs  
else if(nFileLength == -2) yn{U/+  
{ ' @j8tK  
System.err.println("File is not access!"); oF0*X$_X  
} +L#):xr  
else uTP4r  
{ oc&yz>%q  
for(int i=0;i<nStartPos.length;i++) @wXo{p@W  
{ 6r)qM)97  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 1;+(HB  
} q5~fU$ ,  
for(int i=0;i<nEndPos.length-1;i++) 1)M%]I4  
{ DFqVZ  
nEndPos = nStartPos[i+1]; nZUBblRJ)  
} >@^j9{\  
nEndPos[nEndPos.length-1] = nFileLength; )W![TIp  
} .fS1  
} 8f#&CC!L  
6z+*
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No)@#^  
//启动子线程 f@IL2DL}\  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; GSg/I.)S  
for(int i=0;i<nStartPos.length;i++) :*lB86Ly  
{ -Cf< #'x_  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), YZ+<+`Mz<  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), f.u[!T  
nStartPos,nEndPos,i); I*8_5?)g<  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); a~[]Ye@H  
fileSplitterFetch.start(); 26c1Yl,DMn  
} C8 2lT_7"  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), [
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); *:V"C\`^n  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", aAkO>X%[  
nEndPos = " + nFileLength); cX@72  
// fileSplitterFetch[nPos.length-1].start(); gOA]..lh  
*AN2&>Y  
jo
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//等待子线程结束 {2%@I~US  
//int count = 0; _{'HY+M  
//是否结束while循环 G(y@Tor+  
boolean breakWhile = false; F!yejn [  
?gOZY\[ma  
.e%B'  
while(!bStop) U}<;4Px]7v  
{ $`/J V?Z  
write_nPos(); :ugj+  
Utility.sleep(500); qnR
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breakWhile = true; g\ p;  
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for(int i=0;i<nStartPos.length;i++) rgg3{bU/  
{ 'm+)n08[  
if(!fileSplitterFetch.bDownOver) *1;}c z  
{ [.`#N1-@M  
breakWhile = false; t5pf4M7  
break; ~4+=C\r  
} bi[gyl#  
} lTpmoDa%  
if(breakWhile)  $mG&4Y  
break; /S+gh;2OC  
?I.<mdhN#t  
UGJ# "9  
//count++; q#N8IUN}4  
//if(count>4) j:{d'OV  
// siteStop(); 3?GEXO&,E  
} -kd_gbnr3  
|>P`Gl]E  
NI136P  
System.err.println("文件下载结束！"); ~?n)1Vr|  
} r$~ f[cA  
catch(Exception e){e.printStackTrace ();} <ib#PLRM  
} Ym*Ed[S  
u%=M
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rTj
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//获得文件长度 G#;$;  
public long getFileSize() ZO $}m?  
{ d`;_~{sleR  
int nFileLength = -1; {'#^  
try{ ISuye2tExq  
URL url = new URL(siteInfoBean.getSSiteURL()); +9mnxU>  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); OQON~&~  
httpConnection.setRequestProperty("User-Agent","NetFox"); Vee`q.  
 D=nuK25  
1[vmK,N=E  
int responseCode=httpConnection.getResponseCode(); %vO b"K$X  
if(responseCode>=400) BJI R !J  
{ PuhFbgxy  
processErrorCode(responseCode); v/BMzVi  
return -2; //-2 represent access is error .q1OT>  
} &dkjT8L$  
|:i``gFj  
@iwg`j6ol  
String sHeader; czf|c  
gs_nUgcA  
}*4K]3et$  
for(int i=1;;i++) GJY7vS^#  
{ ?B2 T'}
~  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ^\uj&K6l  
//Utility.log(in.readLine()); `}^_>  
sHeader=httpConnection.getHeaderFieldKey(i); 9ci=]C5o3K  
if(sHeader!=null) "$tP>PO{<  
{ L;0ZB=3n  
if(sHeader.equals("Content-Length")) xhIC["z5  
{ FXPw5  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); $b/oiy!=|3  
break; DM%4V|F"  
} PZRm.vC)k  
} %<q l  
else i# 1:DiF  
break; <5Jp2x#  
} 0'm4 )\  
} WX}"Pj/6  
catch(IOException e){e.printStackTrace ();} 47xJ(yO  
catch(Exception e){e.printStackTrace ();} ~)#JwY  
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Utility.log(nFileLength); Oi=>Usd  
YN ~7nOw  
3Q`F x  
return nFileLength; 40}8EP k)  
} Brh<6Btl  
[e+"G <>  
?+S&`%?  
//保存下载信息（文件指针位置） E+AEV`-  
private void write_nPos() X
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{ N6Fj}m&E  
try{ BOLG#}sm  
output = new DataOutputStream(new FileOutputStream(tmpFile)); MmBM\Dnv  
output.writeInt(nStartPos.length); 2 fX-J  
for(int i=0;i<nStartPos.length;i++) U<**Est  
{ `<h}Ygo>k/  
// output.writeLong(nPos); \5$N> 2kO  
output.writeLong(fileSplitterFetch.nStartPos); dIG(7~  
output.writeLong(fileSplitterFetch.nEndPos); \w!G  
} {4g1Wr5=  
output.close(); n_%JXm#\  
} zF'{
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catch(IOException e){e.printStackTrace ();} +%G*)8N3  
catch(Exception e){e.printStackTrace ();} %QUV351H  
} HPAd@5d(  
) w.cCDL c  
C G~)`  
//读取保存的下载信息（文件指针位置） /I3#WUc;![  
private void read_nPos() >8~+[e  
{ 5rqjqfFa  
try{ yG5T;O&  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); cy)gN g  
int nCount = input.readInt(); !6ZkLE[XJ<  
nStartPos = new long[nCount]; z)'dDM D"  
nEndPos = new long[nCount]; Z<Rz}8s  
for(int i=0;i<nStartPos.length;i++) xQC.ap  
{ ysfR@ sH7  
nStartPos = input.readLong(); <D4.kM  
nEndPos = input.readLong(); ?w1_.m|8u  
} e*e}
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input.close(); 2Av3.u8%u  
} `Y-uNJ'.N  
catch(IOException e){e.printStackTrace ();} /_?E0
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catch(Exception e){e.printStackTrace ();} >A|6kzC  
} wh:O
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%b2.JGBqJ  
|,j6cFNw  
private void processErrorCode(int nErrorCode) .!Kdi|a)  
{ h[%`'(  
System.err.println("Error Code : " + nErrorCode); *usfJ-  
} P@:#NU[  
\Nu(+G?e  
MI|DOp  
//停止文件下载 C_?L$3 U0  
public void siteStop() ]`&EB~K&NY  
{ *A`hKx  
bStop = true; ho2o/>Ef3  
for(int i=0;i<nStartPos.length;i++) Z.$ncP0s  
fileSplitterFetch.splitterStop(); 34 W#  
2i#wJ8vrF  
\pB"R$YZ6  
} ?'p`Qv  
} eMVfv=&L<3  
//负责部分文件的抓取 b&A+`d  
**FileSplitterFetch.java L$h.VQv+  
*/ I+w3It  
package NetFox; w-R>gdm  
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l}%!&V0  
import java.io.*; ?@l9T)fF  
import java.net.*; j|9;") 1  
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V^=z\wBZ  
public class FileSplitterFetch extends Thread { ts3%cRN r  
za'Eom-<u  
7rc^-!k  
String sURL; //File URL I@a7AuOw  
long nStartPos; //File Snippet Start Position zTBr
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long nEndPos; //File Snippet End Position <DiD8")4  
int nThreadID; //Thread's ID x&tad+T  
boolean bDownOver = false; //Downing is over ZrnZ7,!@  
boolean bStop = false; //Stop identical X^#48*"a  
FileAccessI fileAccessI = null; //File Access interface R>Fie5?  
@"-<m|lM  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException oJR0sbikP  
{ IP$^)t[  
this.sURL = sURL; ~" B0P>7  
this.nStartPos = nStart; qr$=oCqa  
this.nEndPos = nEnd;
4hg]/X"H#  
nThreadID = id; 5[esW  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 3k5OYUk  
} "8J$7g@n@  
 |X`xJL  
+q"d=  
public void run() afv?z  
{ qi}HJkOq  
while(nStartPos < nEndPos && !bStop) R{5Qb?&wOp  
{ V#^~JJW^  
-<sn+-uE:  
3'Q H\t5  
try{ AYd7qx:~  
URL url = new URL(sURL); g1JD8~a  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ]<A|GY0q1  
httpConnection.setRequestProperty("User-Agent","NetFox"); BQmg$N,F  
String sProperty = "bytes="+nStartPos+"-"; zht^gOs  
httpConnection.setRequestProperty("RANGE",sProperty); U2=5Nt5  
Utility.log(sProperty); 0K`3BuBs  
|[}YM%e  
]nhLv!Co  
InputStream input = httpConnection.getInputStream(); "wmQ,=  
//logResponseHead(httpConnection); -7*,}xV  
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byte[] b = new byte[1024]; o8BbSZVu  
int nRead; .B{3=z^  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ,(}7 ST  
{ hAHl+q)w?  
nStartPos += fileAccessI.write(b,0,nRead); bKYLBu:  
//if(nThreadID == 1) Vc$x?=  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); C[gCwDwl  
} cPi 3UjY~  
XgP7 !  
.6+j&{WNo!  
Utility.log("Thread " + nThreadID + " is over!"); W*e6F?G  
bDownOver = true; ooreforr  
//nPos = fileAccessI.write (b,0,nRead); U")~bU  
} pvQw+jX  
catch(Exception e){e.printStackTrace ();} WmP"u7I4  
} G/J5aj[  
} R+#|<e5@%o  
49^;T;'v  
#+|{l*>  
//打印回应的头信息 YTpSR~!Rj  
public void logResponseHead(HttpURLConnection con) G$}\~dD  
{ DGj:qd(  
for(int i=1;;i++) n'v[[bmu  
{ fySzZ  
String header=con.getHeaderFieldKey(i); hf^,  
if(header!=null) Y[i>  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); di>"\On-  
Utility.log(header+" : "+con.getHeaderField(header)); 2B3H-`  
else YH&`+ +  
break; f%` =>l
 
} b/5?)!I  
} j1*'yvGM  
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kjfZ*V=-  
public void splitterStop() 2aX|E4F  
{ Jm0P~E[n  
bStop = true; 9TBkVbq
V  
} S=~[6;G  
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Mg W0 ).  
} (BEGt'7  
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/* *?Nrx=O*  
**FileAccess.java MzL^u8  
*//文件访问(定位，写) |)* K#%j  
package NetFox; f)l:^/WP+  
import java.io.*; w&hgJ  
@AaM]?=P{  
bdZ[`uMD  
public class FileAccessI implements Serializable{ >A|(mc  
 gPh;  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 "}!|V)K
 
RandomAccessFile oSavedFile; ci0)kxUBF  
long nPos; !qS~Y
A  
pYa8iQ`6U;  
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public FileAccessI() throws IOException 5,}
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{ Fm_^7|  
this("",0); u\ro9l  
} +w[vYKSZm  
7"@^JxYN  
^[,Q2MHCT(  
public FileAccessI(String sName,long nPos) throws IOException g(B&A P_e  
{ M(KsLu1   
oSavedFile = new RandomAccessFile(sName,"rw"); fz\C$[+u  
this.nPos = nPos; R8I%Cyc  
oSavedFile.seek(nPos); SE.r 'J0  
} KiAWr-~gJ  
:m]~o3KRy  
f6vhW66:?x  
public synchronized int write(byte[] b,int nStart,int nLen) njtz,qt_;G  
{ "XlNKBgM  
int n = -1; ukpbx;O:hc  
try{ [Ul"I-K  
oSavedFile.write(b,nStart,nLen); HC(Vu  
n = nLen; C-E~z{  
} 3)88B"E  
catch(IOException e) ~U(`XvR\4  
{ OB`(,m#  
e.printStackTrace (); b3F)$UQ  
} Q)c3=.[>  
g= ~Y\$&  
k#uSH eq7f  
return n; ADK)p?  
} SK [1h
3d  
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} 1AQVj]#S  
qmqWMLfC  
5xC4lT/U  
/* WfpQ
  
**SiteInfoBean.java ">cLPXX  
*/ *;t\!XDgp  
package NetFox; 0`c|ZzY  
VK*Dm:G0  
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public class SiteInfoBean { k#F |  
s|F}Ab
x,^  
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private String sSiteURL; //Site's URL mS
LA4
[4{  
private String sFilePath; //Saved File's Path B|pO2de  
private String sFileName; //Saved File's Name 7OAM  
private int nSplitter; //Count of Splited Downloading File `ppyCUX  
x1H1[0w,i  
x1]J
  
public SiteInfoBean() K8#MQR2@  
{//nSplitter的缺省值为5 k%uR!cL  
//default value of nSplitter is 5 [As9&]Bv5  
this("","","",5); F-AU'o *  
} scX'>\w&c  
S&/,+x'c|  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ?M!Mb-C[  
{ \ vn!SO7  
sSiteURL= sURL; JguPXHa0  
sFilePath = sPath; aItQ(+y  
sFileName = sName; #1*
#3p9UL  
this.nSplitter = nSpiltter; B@cC'F#G  
R!i\-C1 S  
V=^B7a.;>  
} U\*]cw  
A0hKzj  
6$CwH!42F  
public String getSSiteURL() Jq>rA  
{ Z$?(~ln  
return sSiteURL; F+o4f3N  
} %,T=|
5  
4>^LEp  
Kb
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public void setSSiteURL(String value) Hjhgu=  
{ &~mJ ).*  
sSiteURL = value; y0vJ@ %`  
} 0N;~(Vt2  
{zX]41T  
mR["xDHD  
public String getSFilePath() ^'9.VVyz  
{ 4)"S/u  
return sFilePath; dG&^M".(
 
} >{6U1ft):  
~c,CngeL0  
nuKcq!L  
public void setSFilePath(String value) "@z X{^:  
{ Emy=q5ryl  
sFilePath = value; CbGfVdw/c  
} j,n\`7dD$  
[)+wke9  
o6tPQ (Vi  
public String getSFileName() 9xi nX-x;n  
{ 5P Zzaz<  
return sFileName; E5aRTDLq  
} K;z$~;F  
(E;+E\E  
Ez8k.]q
u  
public void setSFileName(String value) *+OS;R1<  
{ |`ya+/ff+  
sFileName = value; ?(Se$iTZ  
} :V3z`}Rl  
za%gD  
8)lrQvZ  
public int getNSplitter() apOXcZ  
{ xKR\w!+Z'  
return nSplitter; &(7=NAQsE  
} dI%?uk  
1=Z!ZY}}e  
3Ccy %;  
public void setNSplitter(int nCount) InI>So%e|<  
{ 3v@h&7<E  
nSplitter = nCount; }u9#S  
} ?g\emhG  
} Nq9\2p  
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H
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/* h1t~hrq  
**Utility.java 3k3C\Cw  
*/ 2HUw^ *3  
package NetFox; }?\^^v h7  
7nm'v'\u+V  
,,SV@y;  
public class Utility { +4$][3.
 
@XJ#oxM^  
fat;5XL@  
public Utility() 3eg6 CdT  
{ ^T:L6:  
ph}%Ay$  
Ur]/kij  
} o%bf7)~s  
|1GOm=GNK  
//线程睡眠 6Df*wi!jI  
public static void sleep(int nSecond) ,<N{Y[n]e  
{
HfZ^ED"}  
try{ ;L,i">_%u[  
Thread.sleep(nSecond); Xp] jF^5  
} j7U&a}(  
catch(Exception e) 1fvN[  
{ M^*\$K%  
e.printStackTrace (); e|?eY)_  
} 2eHVl.C5  
} q
u1+.z=|  
Uks%Mo9on  
//日志 h%U}Y5Ps~  
public static void log(String sMsg) 3.@LAF  
{ $ay!'MK0d  
System.err.println(sMsg); HKr}"`I.  
} 43x2BW&&  
MVnN0K4  
>23$_'2  
public static void log(int sMsg) *|<T@BXn  
{ IU<lF)PF$  
System.err.println(sMsg); (i L*1f   
} -#v1/L/=  
} x3g4r_  
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@I}VD\pF  
/* !zvjgDlZv  
**TestMethod.java PtYG%/s  
*/ IITUM)  
package NetFox; 41R6V>e@9J  
?"*JV1 9  
HCsd$M;Hbv  
public class TestMethod { 5x%Blkx  
51JB,}dGH}  
K-~gIlbQ`  
public TestMethod() JO*/UC>"  
{ ///xx/weblogic60b2_win.exe BPa,P_6(  
try{ F
sm6gE`|n  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); pU9.#O  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 5RvE ),  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 1 _Oc1RM   
fileFetch.start(); JOpH Z?  
} T>]T=  
catch(Exception e){e.printStackTrace ();} s;YbZ*oaMe  
{1Y
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}% f7O  
} 0 zK{)HZ  
q8&l%-d`  
%59uR}\  
public static void main(String[] args)
'B{FRK  
{ 3:MJKS02OD  
new TestMethod(); 5VP0Xa ~  
} ;}iB9 Tl  
} 2cUT bRm  
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