http断点续传简单实现（java)

/* s~z~9#G(6  
**SiteFileFetch.java '%H\k5^  
*/ ,+d\@:  
package NetFox; iL$~d@AEn  
import java.io.*; 8t)?$j$  
import java.net.*; mTj?W$+r  
f-!P[6bY  
*=2sXH1j  
public class SiteFileFetch extends Thread { FxFRrRRH@  
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SiteInfoBean siteInfoBean = null; //文件信息Bean %w3Y!7+  
long[] nStartPos; //开始位置 ^pysoaZCT_  
long[] nEndPos; //结束位置 nOCCOTf  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 KLBX2H2^0  
long nFileLength; //文件长度 n^t!+  
boolean bFirst = true; //是否第一次取文件 m-HL7&iG$  
boolean bStop = false; //停止标志 @2`$ XWD  
File tmpFile; //文件下载的临时信息 xXRlQ|84  
DataOutputStream output; //输出到文件的输出流 F1q6 3  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） W^k|*Y|  
public SiteFileFetch(SiteInfoBean bean) throws IOException Xl %ax!/  
{ X{u\|e{  
siteInfoBean = bean; >Y6iLQ$X  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); fZtuP1-4  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); _)U.5f<  
if(tmpFile.exists ()) 6ec#3~ Y]  
{ |[W7&@hF  
bFirst = false; 2X,`t%o  
read_nPos(); rizWaw5E!8  
} MJM<  
else =#>F' A  
{ u Wxl\+_i  
nStartPos = new long[bean.getNSplitter()]; pGdFeEkB/  
nEndPos = new long[bean.getNSplitter()]; [vTk*#Cl4  
} UGP,/[XI  
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} w(oi6kg  
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public void run() XI\P#"  
{
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//获得文件长度 E<[Y KY  
//分割文件 e X{#FgFc  
//实例FileSplitterFetch <lgX=wx L  
//启动FileSplitterFetch线程 6FkBb!ASk  
//等待子线程返回 se@?:n
1)  
try{ 85_Qb2<'r  
if(bFirst) #D
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{ 3_ ZlZ_Tq  
nFileLength = getFileSize(); X#k:J  
if(nFileLength == -1) tF:AqR:(~  
{ WXQ+`OH7  
System.err.println("File Length is not known!"); PY MofQaZ  
} 9/JBn
 
else if(nFileLength == -2) D@)L?AB1f  
{ -sxu7I  
System.err.println("File is not access!"); ]P>c{  
} Ez / W$U  
else z#B(1uI  
{ )I"I[jDw  
for(int i=0;i<nStartPos.length;i++) k_`h (R  
{ vP%}XEF  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); P
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} oFKTBH:I  
for(int i=0;i<nEndPos.length-1;i++) ?&-$Zog  
{ 7$mB.\|  
nEndPos = nStartPos[i+1]; & zv!cf  
} t=fr`|!  
nEndPos[nEndPos.length-1] = nFileLength; P~;1adi3  
} \ #N))gAQ  
} 89j*uT  
/vI"v4  
:{9HsF"h0  
//启动子线程 S1#5oy2  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ~KczP1p  
for(int i=0;i<nStartPos.length;i++) XEBj=5sG  
{ tL M@o|:  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Z^Yy sf  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), J7HY(7Nx  
nStartPos,nEndPos,i); ?)H:.]7-x  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); P$.$M}rMv  
fileSplitterFetch.start(); |rI;OvZ\  
} 2(5/#$t  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), bg5i+a,?  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Z23T
2  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", UrO&K]Z  
nEndPos = " + nFileLength); P(!%P
p  
// fileSplitterFetch[nPos.length-1].start(); ^kke  
U6.hH%\}@  
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//等待子线程结束 `I8ep=VZ  
//int count = 0; Z3U%Afl2{  
//是否结束while循环 UOyM=#ipY  
boolean breakWhile = false; RL[F 9g  
EQQ@nW{;  
86>@.:d  
while(!bStop) qHvU4v  
{ qcC(#0A>  
write_nPos(); B4*uS (  
Utility.sleep(500);
!ST7@D  
breakWhile = true; }$[@*  
P
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for(int i=0;i<nStartPos.length;i++) _GM?`  
{ <{h\Msx%  
if(!fileSplitterFetch.bDownOver) U "r)C;
5  
{ {|@}xrB  
breakWhile = false; hAt4+O&P  
break; V`9*_8Dx2  
} K{,'%|  
} <oi'yr  
if(breakWhile) *U}-Y*  
break; g W_E  
4|\
  
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//count++; ~0[(-4MA  
//if(count>4) &8yGVi  
// siteStop(); fUfd5W1"  
} zbr^ulr  
fmJK+  
6!
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System.err.println("文件下载结束！"); FFcIOn  
} M,X)rM}Q  
catch(Exception e){e.printStackTrace ();} Kv9FqrDj  
} ]N;nq  
D
?8(n=#[  
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//获得文件长度 edCVIY'1  
public long getFileSize() O*bzp-6\  
{ Qa\,)<'D:  
int nFileLength = -1; PIXqd,  
try{ p|
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URL url = new URL(siteInfoBean.getSSiteURL()); %#PWD7a\  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); >,tJq%  
httpConnection.setRequestProperty("User-Agent","NetFox"); {0np  
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int responseCode=httpConnection.getResponseCode(); -ah)/5j  
if(responseCode>=400)
r[T(R9k  
{ Hz[1c4)'F  
processErrorCode(responseCode); aMxj{*v7  
return -2; //-2 represent access is error ?.uhp  
} "KS"[i!3j  
m+:JNgX6  
'Z=_zG/RX  
String sHeader; fAz4>_4  
5O]ZX3z>  
.qKfhHJ  
for(int i=1;;i++) :8`$BbV  
{ l:bbc!3  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); \ykA7Y%  
//Utility.log(in.readLine()); PC+Soh*  
sHeader=httpConnection.getHeaderFieldKey(i); 2hso6Oy/v{  
if(sHeader!=null) kOdpW  
{ 0VNpd~G$  
if(sHeader.equals("Content-Length")) p:$kX9mT&  
{ ujN~l_4  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); X8}\m%gCU  
break; f*88k='\W  
} g.blDOmlc  
} "PWGtM:L8Y  
else =8TBkxG  
break; ZZwIB3sNhf  
} N!ay#V  
} P*>?/I`G  
catch(IOException e){e.printStackTrace ();} ~`^kP.()  
catch(Exception e){e.printStackTrace ();} W"pHR sf  
%K8YZc(&  
s]`6uyW"  
Utility.log(nFileLength); VAjl?\}6  
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return nFileLength; /.rj\,  
} )?B-en\  
Z+EZ</'(a  

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//保存下载信息（文件指针位置） #*lDKn[vO  
private void write_nPos() U(x$&um(l  
{ f\=,_AQ  
try{ 'rFLG+W  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Pg`+Q^^6S  
output.writeInt(nStartPos.length); R
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for(int i=0;i<nStartPos.length;i++) bF*Kb"!CF  
{ 8'zfq ]g  
// output.writeLong(nPos); EbVC4uY  
output.writeLong(fileSplitterFetch.nStartPos); >Wx9a"H^(  
output.writeLong(fileSplitterFetch.nEndPos); dD'KP4Io@  
} lA4J#  
output.close(); OVgak>$  
} yLnTIE3)  
catch(IOException e){e.printStackTrace ();} Wnp[8IEU  
catch(Exception e){e.printStackTrace ();} n!~QC  
} =>Z4vWX*  
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1|G5 W:  
//读取保存的下载信息（文件指针位置）
=%>E8)Jb  
private void read_nPos() 3BLHd<  
{ +]yVSns 3  
try{ W$l4@A  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); RLLL=?W@  
int nCount = input.readInt(); 6 !fq658  
nStartPos = new long[nCount]; )[&j&AI  
nEndPos = new long[nCount]; -
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for(int i=0;i<nStartPos.length;i++) ~"wnlG-:  
{ 0lcwc"_DZX  
nStartPos = input.readLong(); YY7dw:>e/  
nEndPos = input.readLong(); Zw/??Tq b  
} /z)8k4  
input.close(); lD_iIe~c  
} 1. Q"<[M  
catch(IOException e){e.printStackTrace ();} t)(>E'X x  
catch(Exception e){e.printStackTrace ();} s>>lf&7  
} '$
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private void processErrorCode(int nErrorCode) pf=CP%L  
{ vDc&m  
System.err.println("Error Code : " + nErrorCode); y>g`R^^  
} [t5Dd  
gJ$m'kC;  

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//停止文件下载 ty9(mtH+  
public void siteStop() k9&pX8#  
{ G#'G9/Tm  
bStop = true;
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for(int i=0;i<nStartPos.length;i++) f{]W*!VV-  
fileSplitterFetch.splitterStop(); a-5#8  
bGB5]%v,  
"+4r4  
} w/CD-  
} FvBnmYnW  
//负责部分文件的抓取 l W Lj==  
**FileSplitterFetch.java ;,u7)  
*/ v #Q(g/^  
package NetFox; Pj*"2 LBW#  
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import java.io.*; #~qY%X  
import java.net.*; bLz('mUY  
AiV1 vD`  
xEe3,tb'e  
public class FileSplitterFetch extends Thread { sRGIHT#  
NUX2{8gs  
|\q@XCGei  
String sURL; //File URL M0RVEhX  
long nStartPos; //File Snippet Start Position Dt+uf5o(  
long nEndPos; //File Snippet End Position 'Z^KpW  
int nThreadID; //Thread's ID 4:XVu
  
boolean bDownOver = false; //Downing is over 'ewVn1ME[  
boolean bStop = false; //Stop identical p/&s-GF  
FileAccessI fileAccessI = null; //File Access interface Jd/XEs?<q  
0Y ld!L  
TZ@S?r>^  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 0[SrRpD  
{ I~U;M+n*y  
this.sURL = sURL; 7 [?]DyOf  
this.nStartPos = nStart; 4ew#@  
this.nEndPos = nEnd; a/p /<
 
nThreadID = id; q8fnUK?i  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ;!/g`*?  
} KH76Vts  
L@LT*M  
i@spd5.  
public void run() /hbdQm  
{ $8Y|&P  
while(nStartPos < nEndPos && !bStop) }VXZM7@u  
{ \"hP*DJ"  
&$E.rgtg  
bjGQ04da  
try{ GF awmNZ  
URL url = new URL(sURL); :l?/]K  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); _'DZoOH|VE  
httpConnection.setRequestProperty("User-Agent","NetFox"); 3D"?|rd~  
String sProperty = "bytes="+nStartPos+"-"; )qV&sru.$  
httpConnection.setRequestProperty("RANGE",sProperty); 3k?|-js  
Utility.log(sProperty); |+(Hia,X  
^G]H9qY-e  
,O]AB  
InputStream input = httpConnection.getInputStream(); bR;Wf5  
//logResponseHead(httpConnection); :~+m9r  

+c_8~C  
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byte[] b = new byte[1024]; 7[u$!.4{*  
int nRead; y@Q? guB  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) hO}nc$S  
{ GjvTYg~  
nStartPos += fileAccessI.write(b,0,nRead); 1brKs-z  
//if(nThreadID == 1) \mp5G&+/Q  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); JPfE`NZ  
} @&M$oI$4*  
VyL|d^'f_  
1(12`3  
Utility.log("Thread " + nThreadID + " is over!"); hz_F^gF  
bDownOver = true; &SE+7HXw  
//nPos = fileAccessI.write (b,0,nRead); bB|P`lL  
} Fq9>t/Zj  
catch(Exception e){e.printStackTrace ();} MW6
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} 4\%XC F!  
} Pb-Ft=  
Nt#a_  
}8cX0mZ1j  
//打印回应的头信息 :},/D*v  
public void logResponseHead(HttpURLConnection con) &BDdJwE  
{ Bpw<{U  
for(int i=1;;i++) CD+2 w cy  
{ lm;G8IP`  
String header=con.getHeaderFieldKey(i); {<3>^ o|"  
if(header!=null) !1\jD  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); SMdkD]{g  
Utility.log(header+" : "+con.getHeaderField(header)); XUyoZl?  
else E@F:U*A6%  
break; a:3f>0_t  
} K2GcU_*t  
} WaRYrTDv64  
TGJ\f  
].eY]o}=  
public void splitterStop() YQ+Kl[ec  
{ nE)|6  
bStop = true; !bHM:!6^  
} bu2'JI
DR  
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>WW5Apy[  
} d%istFL)  
@
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/* ?ExfxR!~  
**FileAccess.java o^Y'e+T"  
*//文件访问(定位，写) DOXRU5uP3  
package NetFox; /N@0qQ  
import java.io.*; uREc9z`Q'  
B(MO!GNg=  
u%O^hcfb  
public class FileAccessI implements Serializable{ 55oLj.l^j  
`.dTkL
 
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 e?G*q)l  
RandomAccessFile oSavedFile; T^GdN_qF  
long nPos; [.;%\>Qk<  
mT6q}``vtG  
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public FileAccessI() throws IOException LgP>u?]n  
{ lMBX!9z  
this("",0); m\/,cc@,  
} ,$h(fM8GC  
^E$(1><-a  
CYtjY~  
public FileAccessI(String sName,long nPos) throws IOException *#lBQBH|.  
{ M!Z*QY."P  
oSavedFile = new RandomAccessFile(sName,"rw"); x*me'?q  
this.nPos = nPos; 5[,+\  
oSavedFile.seek(nPos); UU iNR  
} K/vxzHSl  
O`i)?BC  
|P~O15V*Q  
public synchronized int write(byte[] b,int nStart,int nLen) 7q%|4Z-~  
{ Z}8k[*.  
int n = -1; s, n^  
try{ y]}b?R~p=  
oSavedFile.write(b,nStart,nLen); [)#u<lZ<~  
n = nLen; 5LQk8NPh  
} |XKOXa3.  
catch(IOException e) vG]GQ#  
{ { p1lae  
e.printStackTrace (); xwPI  
} -7>^ rR V  
>=if8t!  
;>NP.pnA
)  
return n; O(VxMO  
} ,YjxCp3  
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} r5o
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;\N79)Gk  
/* RX:R*{]-  
**SiteInfoBean.java ?4^};wDb2  
*/ zhNQuK,L  
package NetFox; cZqfz  
{'NBp0i  
tcZa~3
.  
public class SiteInfoBean { 6`acg'sk>  
*oCxof9JA  
jz*0`9&_  
private String sSiteURL; //Site's URL {$;2HbM(  
private String sFilePath; //Saved File's Path Gb;99mE  
private String sFileName; //Saved File's Name _=pWG^a  
private int nSplitter; //Count of Splited Downloading File wb b*nL|P  
-$.0Dc)3!  
<PX.l%  
public SiteInfoBean() 4sTMgBzw  
{//nSplitter的缺省值为5 e,(a6X  
//default value of nSplitter is 5 H( vx/q  
this("","","",5); RT,:hH  
} `?l3Ct*  
vv+km+  
/jM_mrpz  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Nb0Ik/:<  
{ C8ZL*9U  
sSiteURL= sURL; =~&VdPZ  
sFilePath = sPath; 6ZcXS  
sFileName = sName; *r;xw  
this.nSplitter = nSpiltter; m^<p8KZ  
RND9D\7  
#.H}r6jqs  
} eeM?]J-
 
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public String getSSiteURL() eNbpwn
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{ M*w'1fT  
return sSiteURL; TkRm
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} QOH<]~3J  
wPX*%0]  
E;9>ePd@  
public void setSSiteURL(String value) H]&gW/=  
{ 2s\BY%XY  
sSiteURL = value; y\D=Z N@  
} 1'JD=  
E"6X|I n  
5!(?m~jJ  
public String getSFilePath() 5wv fF.v  
{ uH:YKH':/  
return sFilePath; -_em%o3XC  
} bWmw3w  
O6X"RsI}  
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public void setSFilePath(String value) uOd&XW  
{ 6KRO{QK  
sFilePath = value; hr/o<#OW  
} pr&=n;_ n  
r^1+cwy/7P  
T^:fn-S}=  
public String getSFileName() x#*QfE/E(@  
{ A&"%
os  
return sFileName; jQ+sn/ROp  
} h&;t.Gdf  
$n!K6fkX%  
y >+mc7n  
public void setSFileName(String value) WQ6"0*er  
{ (V?:]  
sFileName = value; (Un_!)  
} -LW[7s$  
F_H82BE+3  
~}"]&%Q{J  
public int getNSplitter() [p;E~-S  
{ (Pbg[AY  
return nSplitter; p B;
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} hA1-){aw3q  
t2BL(yB  
eq4C+&O&  
public void setNSplitter(int nCount) &--ej|n  
{ &#yR;{  
nSplitter = nCount; /JkC+7H4  
} vVl; |  
} 3?n>yS  
x1&W^~  
Qnd5X`jF#  
/* =#gEB#$x:  
**Utility.java Q'O[R+YT ,  
*/ u8GMUN  
package NetFox; Xx:F)A8O  
!> }.~[M  
??60,
m:]  
public class Utility { '6y}ZE[  
zOgTQs"ZH  
c(;a=n(E#  
public Utility()  -!W<DJ*  
{ RPd}Wf  
/zDi9W*~1  
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} h\v'9  
JM1R ;i6  
//线程睡眠 ]0hrRA`  
public static void sleep(int nSecond) =0uAE7q(9  
{ WOuEWw=  
try{ NT@;N/I  
Thread.sleep(nSecond); `\Hf]b  
} [(1c<b2r  
catch(Exception e) ;qH
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{ >D201&*G%  
e.printStackTrace (); [kE."#  
} U- )i+}Ng  
} -'~LjA(  
jck}" N  
//日志 V3 ~~  
public static void log(String sMsg) |$5[(
6T|  
{ 5j~$Mj`  
System.err.println(sMsg); e[hcJz!D  
} Aq
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(?nCyHC%g  
public static void log(int sMsg) W`c'=c  
{ */|BpakD<  
System.err.println(sMsg); +\v?d&.f0  
} {%_L=2n6  
} q$=#A7H>3)  
2RSt)3!},  
itC-4^  
/* GvBHd%Ot  
**TestMethod.java nqLA}u4IM  
*/ "I(xgx*  
package NetFox; 5LOo8xN  
*QH28%^  
8@tV9+u  
public class TestMethod { %n*-VAfE\  
K5lmVF\$P  
~c\e'&sc;  
public TestMethod() iNWw;_|1  
{ ///xx/weblogic60b2_win.exe n2na9dX)w  
try{ B007x{-L  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ^?Vq L\V
5  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); GEi MmH?  
SiteFileFetch fileFetch = new SiteFileFetch(bean); }
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fileFetch.start(); =|#w.(3y  
} z[FI2jl  
catch(Exception e){e.printStackTrace ();} ;z
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z6}Pj>1  
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} [,\i[[<  
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09x+Tko9;*  
public static void main(String[] args) ;:^ Lv  
{ v+7*R)/  
new TestMethod(); g?$e^ls  
} 2:/u2K  
} {SHqW5VX  
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