http断点续传简单实现（java)

/* gc[BP>tl\  
**SiteFileFetch.java H\^zp5/  
*/ 2t3DQ  
package NetFox; (kFg2kG  
import java.io.*; C_rA'Hy  
import java.net.*; z:JQ3D7/we  
i9=*ls^Cx  
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public class SiteFileFetch extends Thread { )Zbrg~-@  
=K8z8K?  
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SiteInfoBean siteInfoBean = null; //文件信息Bean rsPo~nA  
long[] nStartPos; //开始位置 }M|,Z'@*  
long[] nEndPos; //结束位置 6)#=@i` \  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 [6}>
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long nFileLength; //文件长度 DRy,n)U&  
boolean bFirst = true; //是否第一次取文件  jT$  
boolean bStop = false; //停止标志 e:T8={LU2W  
File tmpFile; //文件下载的临时信息 CGCI3Z'  
DataOutputStream output; //输出到文件的输出流 Gi7p`F.  
NU/:jr.W#  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ,5Nf9z!hk(  
public SiteFileFetch(SiteInfoBean bean) throws IOException P7|x=Ew;`  
{ T*bBw  
siteInfoBean = bean; T~G~M/  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); tEl_a~s*3?  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); /s|4aro  
if(tmpFile.exists ())
+)U>mm,  
{ --BS/L-  
bFirst = false; tjWf`#tH>H  
read_nPos(); oRZ--1oR_  
} 4cQ|"sOzD  
else rI;84=v2&9  
{ fKkH [  
nStartPos = new long[bean.getNSplitter()]; d'UCPg<Y  
nEndPos = new long[bean.getNSplitter()]; Cj3C%W  
} >sl#2,br  
.{-C*  
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} /{sFrEMP\  
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public void run() k=``Avp?  
{ Z+M* z;  
//获得文件长度 {<#~Ya-  
//分割文件 >[&Z
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//实例FileSplitterFetch oJln"-M1nx  
//启动FileSplitterFetch线程 dHJ#xmE!pP  
//等待子线程返回 m6iQB\ \  
try{ =ec"G2$?"  
if(bFirst) |x/00XhS  
{ W,-fnJk  
nFileLength = getFileSize(); TZ>_N;jTZ  
if(nFileLength == -1) J{qpGRQNa  
{ m)oGeD( !  
System.err.println("File Length is not known!"); M9d
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} e>~7RN  
else if(nFileLength == -2) xp;CYr"1}  
{ uYy&<_r  
System.err.println("File is not access!"); nAY'1!Oi  
} l 4e`-7  
else M~"93Q`f^  
{ ? ht;ZP  
for(int i=0;i<nStartPos.length;i++) P(Wr[lH\y  
{ x2@W,?oPm  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); U%T{~f  
} bS"zp6Di  
for(int i=0;i<nEndPos.length-1;i++) r?:xD(}Q  
{ PZE{-TM?W  
nEndPos = nStartPos[i+1]; ZT1IN6;8W  
} ,I^:xw_  
nEndPos[nEndPos.length-1] = nFileLength; #a|.cm>6  
} '~;vp  
} ]s<}'&  
na-mh E,H  
p6|RV(?8  
//启动子线程 p8_ CY[U  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; y~-dQ7r  
for(int i=0;i<nStartPos.length;i++) Yj#4{2A  
{ |a{~Imz{  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), gkRbb   
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), #d
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nStartPos,nEndPos,i); qEy]Rc%  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ;rjd?r  
fileSplitterFetch.start(); ]^c]*O[8  
} 'pQ\BH  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Bkh1
VAT  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Yfjp:hg/!  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", {- Y.C
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nEndPos = " + nFileLength); y>jP]LR4  
// fileSplitterFetch[nPos.length-1].start(); b9cY  
6E0{(*  
zilM+BZ8  
//等待子线程结束 Qk h}=3u  
//int count = 0; gK+/wTQ%  
//是否结束while循环 R^ &nBwp  
boolean breakWhile = false; f zsD  
+x_9IvaW&?  
29
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while(!bStop) .^aqzA=]  
{ u{d\3-]/  
write_nPos(); W&H
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Utility.sleep(500); jGaI6G'N  
breakWhile = true; V<W$h`  
nr>Os@\BU  
-FrNk>  
for(int i=0;i<nStartPos.length;i++) 3,[#%}1(S  
{ 2B`#c}PP  
if(!fileSplitterFetch.bDownOver) 6&KvT2?tA`  
{ j]5mzz~  
breakWhile = false; R[T94U  
break; 22_%u=p-|  
} hUO&rov3@  
} +:jx{*}jo  
if(breakWhile) 3Lw&HtH  
break; GT3?)g{Z  
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RI</T3%~  
//count++; +q-/~G'  
//if(count>4) 9fQFsI  
// siteStop(); 3sF^6<E  
} hCFgZiH2  
[8$
K i$;  
}=T=Z#OgH  
System.err.println("文件下载结束！"); " _{o}
8L  
} OD~B2MpM>  
catch(Exception e){e.printStackTrace ();} x!RpRq9  
} ^oYudb^%  
unZYFA}(  
A1uo@W  
//获得文件长度 `Eq~W@';Q0  
public long getFileSize() ?Ja&LNI9S  
{ 'vc>uY  
int nFileLength = -1; io
^L
[  
try{ 'j27.Ry.  
URL url = new URL(siteInfoBean.getSSiteURL()); iB0#Z
_  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); M*n@djL$\~  
httpConnection.setRequestProperty("User-Agent","NetFox"); _&xi})E^O]  
lU&[){  
KYN{Dh]-}  
int responseCode=httpConnection.getResponseCode(); |jT^[q(z  
if(responseCode>=400)
9f U,_`r  
{ l Taw6;  
processErrorCode(responseCode); <]e0TU?bk  
return -2; //-2 represent access is error 6xq/  
} bDq[j8IT6  
j$ h>CZZ  
Oiz@tEp=_  
String sHeader; NuQ l  
<)am]+Lswy  
@})]4H  
for(int i=1;;i++) ;2\+O"}4H  
{ /.m&rS  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); glo Y@k~  
//Utility.log(in.readLine()); bjCO@t  
sHeader=httpConnection.getHeaderFieldKey(i); :+*q,lX8  
if(sHeader!=null) pN?geF~t|  
{ }XcYIo#+t  
if(sHeader.equals("Content-Length")) Al-;-t#Dc  
{ YRRsbm{  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); '2X6>6`w  
break; :Y)jf
 
} %3;vDB*L$  
} $vjl-1x
&  
else MIF`|3$,  
break; S;L=W9=wby  
} bpp{Z1/4  
} _`-trE.  
catch(IOException e){e.printStackTrace ();} ckhU@C|=*  
catch(Exception e){e.printStackTrace ();} E8LA+dKN:  
jqv"8S5  
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Utility.log(nFileLength); b;k3B7<  

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return nFileLength; 4Fs5@@>X  
} RM|2PG1m  
2uZ4$_  
R q |,@  
//保存下载信息（文件指针位置） fWk,k*Z9  
private void write_nPos() ta+MH
,  
{ :XFr"aSt  
try{ !9p;%Ny`  
output = new DataOutputStream(new FileOutputStream(tmpFile)); XV %DhR=  
output.writeInt(nStartPos.length); |9'
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for(int i=0;i<nStartPos.length;i++) bpgvLZb>s  
{ z}z 6Vg  
// output.writeLong(nPos); T0TgV  
output.writeLong(fileSplitterFetch.nStartPos); k3yA*Ec  
output.writeLong(fileSplitterFetch.nEndPos); =9yh<'583  
} T j(MIFi|5  
output.close(); j0`)mR}  
} K6d2}!5  
catch(IOException e){e.printStackTrace ();} ,$A'Y  
catch(Exception e){e.printStackTrace ();} {a9(
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} 2&o jQhe  
I6-.;)McO  
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//读取保存的下载信息（文件指针位置） >K;DBy*  
private void read_nPos() ^Iy'G44  
{ 6 @A'N(I=O  
try{ dn1Fwy.  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ?%A9}"q]  
int nCount = input.readInt(); ;Y9-0W  
nStartPos = new long[nCount]; 6m$lK%P{1  
nEndPos = new long[nCount]; MP_LdJM1E  
for(int i=0;i<nStartPos.length;i++) U]AJWC6  
{ .$"13"  
nStartPos = input.readLong(); #T3dfVW
v  
nEndPos = input.readLong(); cKE
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} h"3Mj*
s  
input.close(); N(Sc!rX  
} +oevNM  
catch(IOException e){e.printStackTrace ();} \`U=pZJ  
catch(Exception e){e.printStackTrace ();} XT%\Ce!  
} r\T'_wo  
pt$\pQ  
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private void processErrorCode(int nErrorCode) sOqT*gwr:  
{ hZ`<ID  
System.err.println("Error Code : " + nErrorCode); {|{;:_.>  
} 'zhv#&O  
8yDe{  
Rl{e<>O\^  
//停止文件下载 ~J:]cy)Q  
public void siteStop() cw"Ou%  
{ s3sPj2e{  
bStop = true; 9T#${NK  
for(int i=0;i<nStartPos.length;i++) %EH{p@nM&-  
fileSplitterFetch.splitterStop(); ~YRG9TK  
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} Q].p/-[(  
} (Cb;=:3G  
//负责部分文件的抓取 of=N+ W  
**FileSplitterFetch.java SceK$  
*/ b[KZJLZ)  
package NetFox; pf$gvL  
4G2iT+X-  
"IN[(  
import java.io.*; .+(R,SvN%<  
import java.net.*; %k'>bmJ  
<&RpGAk%I  
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public class FileSplitterFetch extends Thread { $a'}7Q_  
=&I9d;7  
IOT-R!.5V  
String sURL; //File URL #w@V
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long nStartPos; //File Snippet Start Position Qo~|[]GE  
long nEndPos; //File Snippet End Position J'C9}7G  
int nThreadID; //Thread's ID `0, G'F  
boolean bDownOver = false; //Downing is over t>!O
k  
boolean bStop = false; //Stop identical 46##(4RF  
FileAccessI fileAccessI = null; //File Access interface i_(6}Y&  
|=js!R|  
H
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException N 9W,p2  
{ rS8}(lf  
this.sURL = sURL; ykYef  
this.nStartPos = nStart; -v! ;  
this.nEndPos = nEnd; YeS5%?Fk  
nThreadID = id; zfw=U \  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 qV0GpVJZU?  
} :cvT/xhO  
G=/^]E  
!oa/\p  
public void run() Rt>mAU$}  
{ 5=#2@qp  
while(nStartPos < nEndPos && !bStop) $5:I~-mx  
{ xLSf /8e  
4sq](!A  
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try{ `ZU]eAV  
URL url = new URL(sURL); 9ZNzC i!  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); hof>:Rk  
httpConnection.setRequestProperty("User-Agent","NetFox"); :nOI|\rC  
String sProperty = "bytes="+nStartPos+"-"; [,3E#+y  
httpConnection.setRequestProperty("RANGE",sProperty); q|V|Jl  
Utility.log(sProperty); ^8KxU  
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iURSYR  
InputStream input = httpConnection.getInputStream(); mUy>w  
//logResponseHead(httpConnection); d uP0US  
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"U!Vdt2vp  
byte[] b = new byte[1024]; (mplo|>  
int nRead; ~O~iP8T  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) EW`3$J;  
{ zZ,"HY=jN  
nStartPos += fileAccessI.write(b,0,nRead); ++n_$Qug  
//if(nThreadID == 1) 0avtfQ +f  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); w75Ro6y  
} 10Q!-K),p  
IrUoAQ2xpG  
V?)YQB  
Utility.log("Thread " + nThreadID + " is over!"); eX1_=?$1P  
bDownOver = true; fr'DV/T  
//nPos = fileAccessI.write (b,0,nRead); $xCJ5M4  
} %(|-+cLW+  
catch(Exception e){e.printStackTrace ();} 8DX5bB  
} 7 0PGbAD  
} m>|7&l_  
<0;G4fE7[H  
d3\KUR^  
//打印回应的头信息 BiDyr  
public void logResponseHead(HttpURLConnection con) |ZC'a!  
{ T% GR{mp  
for(int i=1;;i++) +koW3>  
{ >{l b|Vx  
String header=con.getHeaderFieldKey(i); \x:} |   
if(header!=null) 3?D{iMRM  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); #0?3RP  
Utility.log(header+" : "+con.getHeaderField(header)); "!_vQ^y  
else R;pIi/yDRe  
break; BNe>Lko  
} ~^'WHuzPy  
} ?gBFfi  
IwBO#HR
~)  
f:t j   
public void splitterStop() 6q8PLyIp  
{ r9*6=*J|  
bStop = true; EEMRy  
} Rn`D
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} RP^vx`9h  
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sgnc$x"  
/* @^J>.
g  
**FileAccess.java nN^lY=3  
*//文件访问(定位，写) unNN&m#@  
package NetFox; NB5lxaL  
import java.io.*; R T~oJ~t;  
ta<8~n^?  
xB]^^NYE=  
public class FileAccessI implements Serializable{ -knP5"TB  
CMyz!jZ3  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 K"hnGYt?  
RandomAccessFile oSavedFile;
4'tY1d  
long nPos; ]omBq<ox'Y  
'vYt_T  
!]5V{3  
public FileAccessI() throws IOException 17`-eDd  
{ ?*[35XUd  
this("",0); g7lPQ_A*  
} x8x-b>|$&<  
1|AY&u%fiP  
fz?woVn  
public FileAccessI(String sName,long nPos) throws IOException :`lP+y?a1  
{ \j-:5M#m  
oSavedFile = new RandomAccessFile(sName,"rw"); Sx (E'?]  
this.nPos = nPos; B&BL<X r  
oSavedFile.seek(nPos); &;`E3$>  
} u.*}'C>^^v  
K`j:F>b  
,b5vnW\  
public synchronized int write(byte[] b,int nStart,int nLen) 6'x3g2C/  
{ )/Gi-::  
int n = -1; O<$j}?2  
try{ =q|//*t2  
oSavedFile.write(b,nStart,nLen); :Rnwyj])  
n = nLen; 2[j`bYNe  
} lA;qFXaN>  
catch(IOException e) K`60[bdp  
{ 
:6&#u.\u  
e.printStackTrace (); ]"?<y s  
} /1D.Ud^  
i)Q d>(v  
G'';VoW=  
return n; 0P{8s  
} FD~ UF;VQ  
;g;1<? [  
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} ^QG<_Dm]  
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ori[[~OyB  
/* FQE(qltf,
 
**SiteInfoBean.java cct/mX2&~  
*/ .6I'V3:Kg  
package NetFox; :h/v"2uDN  
eAqpP>9n  
ITEf Q@#jU  
public class SiteInfoBean { M;NIcM  
s?&S<k-=fr  
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private String sSiteURL; //Site's URL R3LIN-g(  
private String sFilePath; //Saved File's Path :zvAlt'q=  
private String sFileName; //Saved File's Name ^<uQ9p^B  
private int nSplitter; //Count of Splited Downloading File V]"pM]>3X  
Z}Q/u^Z  
HD1/1?y!@q  
public SiteInfoBean() WTjmU=<\  
{//nSplitter的缺省值为5 vS[\j  
//default value of nSplitter is 5 ;Bw3@c  
this("","","",5); ^R)]_  
} 2$VSH&  
feeHXKD|  
1'iQlnMO@  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) g6S-vSX,  
{ }RYPr  
sSiteURL= sURL; -}( o+!nl  
sFilePath = sPath; #JY>  
sFileName = sName; "3|OB, <;:  
this.nSplitter = nSpiltter; -j:yEZ4Oy  
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.2_
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} m(EVC}Y  
6+"gk(  
&p*
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public String getSSiteURL() -^;,m=4{3  
{ ]scr@e  
return sSiteURL; 'A\0^EvVv  
} P"t Dq&  
k,8^RI07@  
t]iKU@3  
public void setSSiteURL(String value) %K7;ePu  
{ Z!jJ93A"  
sSiteURL = value; Ke]'RfO\  
} ,^<39ng  
{ot6ssT=D  
=<zlg~i  
public String getSFilePath() "(kiMog-  
{ E9t8SclV  
return sFilePath; "Vp:Sq9y  
} S
J:Teab  
vq-;wdq?2  
_J#oAE5]!  
public void setSFilePath(String value) /F''4%S?E  
{ C@-cLk  
sFilePath = value; ^P A|RFP  
} hstGe>f[6  
Jw^my
4  
UlKg2p  
public String getSFileName() l|vT[X/g  
{ "?W8o[c+  
return sFileName; !x||ObW\H  
} )nK+`{;@!  
1=!2|D:C)i  
r(_Fr#Qn  
public void setSFileName(String value) * kUb[  
{ 5lM 3In@  
sFileName = value; d-W*`:Q
 
} TIaiJvo  
n!lE|if  
[9Tnp]q  
public int getNSplitter() "T<7j.P?  
{ f8UO`*O  
return nSplitter; lL5*l,)To  
} 5$X 8|Ve  
q./jYe  
KZaiy*
>)  
public void setNSplitter(int nCount) hewc5vrL  
{ P=9UK`n  
nSplitter = nCount; &zVXd  
} IlI5xkJ(  
} Mii&doU  
9y} J|z  
> %Hw008  
/* 6x/o j`_[  
**Utility.java V>UlL&V  
*/ YhooD,[.  
package NetFox; hgwS_L  
HW'I$ .  
'dv
(  
public class Utility { s.KfMJ"u[  
vkM_a}%<  
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public Utility() >%n6n! "  
{ |%3>i"Y@AK  
4$ah~E>,t  
LfCgvq6/pO  
} 62G%.'7  
AI,E9  
//线程睡眠 300[2}Y]  
public static void sleep(int nSecond) 9+.3GRt7  
{ /c4$m3?]  
try{ p!<PRms@  
Thread.sleep(nSecond); { Q!Xxe>6  
} +apn3\_  
catch(Exception e) 1}p:]/;  
{ 5>=4$!`  
e.printStackTrace (); f3h]t0M  
} 2n#H%&^?a  
} }/IP\1bG  
(hRg0Z=  
//日志 1 .o0"  
public static void log(String sMsg) sqRvnCD!  
{ ,zJ:a
>v  
System.err.println(sMsg); -b?s\X  
} hQvI}  
V{\1qg{  
T$;BZ=_  
public static void log(int sMsg) M~Er6Zg  
{ _=cuOo"!  
System.err.println(sMsg); 0wF)bQv1  
} GW7+#  
} &b-&0rTqz  
tZ*>S]qD  
lACS^(  
/* "tD
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**TestMethod.java r $YEq5  
*/ )2u_c=  
package NetFox; UjyrmQf  
9PaV*S(\TR  
, 0?_? GO  
public class TestMethod { ^$rqyWZYp  
<u?\%iJ"  
Wi~?2-!   
public TestMethod() }b{7+ + Ah  
{ ///xx/weblogic60b2_win.exe +]~}kvk:  
try{ hxw6^EA  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); GK3cQw  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); :01B)~^  
SiteFileFetch fileFetch = new SiteFileFetch(bean); @Yw42`>!s  
fileFetch.start(); e{^lD.E  
} '?3
(&  
catch(Exception e){e.printStackTrace ();} Ty3.u9c4  
1.Neg|  
{Wr5F9q  
} ItZ*$I1<  
gXY]NWI  
9pk-#/ag  
public static void main(String[] args) s>{\^T7y  
{ $2Bll5!]  
new TestMethod(); "od2i
\  
} =t|,6Vp  
} 7dR]$~+*e  
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