http断点续传简单实现（java)

/* M,:GMO:?a  
**SiteFileFetch.java ^c
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*/ 5^[V%4y>  
package NetFox; WG<D+P
 
import java.io.*; y~;Kf0~  
import java.net.*; 'R?;T[s%  
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"5]GEzM3O  
public class SiteFileFetch extends Thread { ^O4.$4t|  
2,'m]`;GNr  
=3Y?U*d  
SiteInfoBean siteInfoBean = null; //文件信息Bean %J7 ;b<}To  
long[] nStartPos; //开始位置 H7*/  
long[] nEndPos; //结束位置 a+IU<O-J?  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 |no '^  
long nFileLength; //文件长度 
*cJ GrLC  
boolean bFirst = true; //是否第一次取文件 9aYCU/3  
boolean bStop = false; //停止标志 H 2\KI(  
File tmpFile; //文件下载的临时信息 d+Pfi)+(I  
DataOutputStream output; //输出到文件的输出流 BY6QJkI9x  
PWx2<t<;9  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） &`G
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public SiteFileFetch(SiteInfoBean bean) throws IOException _=8x?fC:rl  
{ sZ7{_}B  
siteInfoBean = bean; EnZrnoGM  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); %YA=W=Yd  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 4w\cS&X~C  
if(tmpFile.exists ()) (+(YO\ng6  
{ ,J~kwJ$
L  
bFirst = false; Tw);`&Ulo  
read_nPos(); PO]z'LD  
} cYq<.A(hVj  
else yiiYq(\{  
{ g#T8WX{(V  
nStartPos = new long[bean.getNSplitter()]; #:e52
=  
nEndPos = new long[bean.getNSplitter()]; RT4ns+J1  
} C]p3,G,oN  
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} 2/x+7F}w5  
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public void run() 9#xcp/O  
{ mn)kd  
//获得文件长度 &U*=D8!0  
//分割文件 A#\NVN8sk  
//实例FileSplitterFetch V)oUSHillH  
//启动FileSplitterFetch线程 /T!S)FD\/v  
//等待子线程返回 *O+
G}_}  
try{ |ffM6W1:  
if(bFirst) oyiEOC  
{ udMDE=1~L  
nFileLength = getFileSize(); ;|5m;x/a  
if(nFileLength == -1) FcB]wz  
{ #%rXDGDS  
System.err.println("File Length is not known!"); ! jm>  
} Uo#%f+t  
else if(nFileLength == -2) MD%_Z/NL  
{ t-)C0<  
System.err.println("File is not access!"); }E+#*R3auB  
} K1AI:$H  
else G>qzAgA  
{ qCi6kEr  
for(int i=0;i<nStartPos.length;i++) %(79;#2`  
{ 2j+v\pjYC  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); za`  
} @2yi%_]h  
for(int i=0;i<nEndPos.length-1;i++) sk.<|-(o  
{ iP6$;Y{ZA  
nEndPos = nStartPos[i+1]; ?kqo~twJ  
} ,W;\6"Iwx'  
nEndPos[nEndPos.length-1] = nFileLength; {L$]NQdz  
} W9D]s~bO;  
} ?6P P_QY  
_@3@_GE  
nlQ<Aa-%  
//启动子线程 4W &HUQ?^  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; CqDKQQ  
for(int i=0;i<nStartPos.length;i++) q90eB6G0g  
{ Mhc!v, D$  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), (iXo\y`z  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), N:[22`NP  
nStartPos,nEndPos,i);
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Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos);  m_LW<'  
fileSplitterFetch.start(); i Tg?JoE2  
} B{^o}:e  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), HS =qK  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); uO
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// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", \$n?J(N  
nEndPos = " + nFileLength); po~V{>fUm  
// fileSplitterFetch[nPos.length-1].start(); ;cgc\xm>  
@0S3`[/
U  
uDJi2,|n  
//等待子线程结束 ~3<Li}W  
//int count = 0; {p&LwTnf  
//是否结束while循环 .{%~4$yu7  
boolean breakWhile = false; gDU~hv  
:biM}L  
}u8o*P|,  
while(!bStop) =(Y 1y$  
{ n8n(<  
write_nPos(); -`x$a&}  
Utility.sleep(500); [H
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breakWhile = true; .]}kOw:(#  
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m{4e+&S|  
for(int i=0;i<nStartPos.length;i++) eY^;L_7}p  
{ MQ>.^]B]o  
if(!fileSplitterFetch.bDownOver) 6m"_=.k%  
{ %T4htZa  
breakWhile = false; *u^N_y  
break; b0|q@!z>  
} {KYbsD  
} m`l3@Z  
if(breakWhile) ,y@`wq>O  
break; >Ng7q?h   
a"uO0LOb  
gmkD'CX*A  
//count++; x;ym_UZ6e  
//if(count>4) \' (_r  
// siteStop(); iTJSW  
} t>p!qKrE'J  
lL_M=td8W  
GInU7y904  
System.err.println("文件下载结束！"); teh$W<C  
} jsL\{I^>  
catch(Exception e){e.printStackTrace ();} 0O+[z9  
} YcW[BMy5h  
U9GmkXRix  
eV$pza  
//获得文件长度 mVFz[xI  
public long getFileSize() $xqI3UaX  
{ <Hw)},_*  
int nFileLength = -1; ckFnQhW  
try{ R r7
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URL url = new URL(siteInfoBean.getSSiteURL()); ~RGZY/4  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); tr3Rn :0]  
httpConnection.setRequestProperty("User-Agent","NetFox"); (GB2("p`  
h&d%#6mB  
<>\s#Jf/  
int responseCode=httpConnection.getResponseCode(); a-w=LpVM
 
if(responseCode>=400) Ba
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{  Gh;Ju[6  
processErrorCode(responseCode); `|@#~  
return -2; //-2 represent access is error A;VjMfoB  
} <8#Q5   
IH|PdVNtg  
)QS4Z{)U  
String sHeader; VbR/k,Co  
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Fr/3Qp@S  
for(int i=1;;i++) ? ->:,I=<~  
{ Vp{e1xpY  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Khd"  
//Utility.log(in.readLine()); "J:~Aa%
_  
sHeader=httpConnection.getHeaderFieldKey(i); xE%1C6~C<  
if(sHeader!=null) q2v:lSFY  
{ 0\3mS{s  
if(sHeader.equals("Content-Length")) nk.m Gny  
{ j/"{tMqQp  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); U(#)[S,  
break; wcz|Zy  
} pm$ZKM  
} |tL57Wu93  
else tj:3R$a  
break; H}G=%j0  
} =*EIe z*.x  
} @pq#?  
catch(IOException e){e.printStackTrace ();} *xm(K+j  
catch(Exception e){e.printStackTrace ();} HsrIw  
c"qaULY  
jSa9UD  
Utility.log(nFileLength); TS0x8,'$q  
0].x8{~o  
0uX"KL]Elf  
return nFileLength; sjh>i>t  
} q;co53.+P)  
];BGJ5^j  
01v7_*'R  
//保存下载信息（文件指针位置） 4u}"ng   
private void write_nPos() |GPR3%9  
{ o!.\+[  
try{ %jaB>4.A:  
output = new DataOutputStream(new FileOutputStream(tmpFile)); B&^WRM;7t  
output.writeInt(nStartPos.length); ke.{wh\0  
for(int i=0;i<nStartPos.length;i++) VrL==aTYXs  
{ V=yRE  
// output.writeLong(nPos); gp07I{0~m  
output.writeLong(fileSplitterFetch.nStartPos); 2kg<O%KA`c  
output.writeLong(fileSplitterFetch.nEndPos); :|hFpLt  
} +Kc1a;  
output.close(); x1:#rb'  
} ^`b&fbv  
catch(IOException e){e.printStackTrace ();} Tj &PB_v1  
catch(Exception e){e.printStackTrace ();} {v&c5B~,\  
} ~F5JN^5Y  
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%7tQam  
//读取保存的下载信息（文件指针位置） l5sBDiir%  
private void read_nPos() z{h#l!Edh  
{ `J*~B  
try{ :eaqUW!Y  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 3w&fN3 1  
int nCount = input.readInt(); En&bwLu:s  
nStartPos = new long[nCount]; f:$LVpXS-  
nEndPos = new long[nCount]; Hya  ";'  
for(int i=0;i<nStartPos.length;i++) 5rG&Z5  
{ _@es9  
nStartPos = input.readLong(); K:}~8 P>^  
nEndPos = input.readLong(); ^/;W;C{4
 
} diXb8L7B;  
input.close(); Wtl0qug  
} rBBA`Ut@F  
catch(IOException e){e.printStackTrace ();}  y!6+jrI  
catch(Exception e){e.printStackTrace ();} HN'r ZAZ(  
} =)Z!qjf1U  
+uR|0Jo8X  
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private void processErrorCode(int nErrorCode) eIVCg-l}  
{ X8!=Xjl)  
System.err.println("Error Code : " + nErrorCode); Z2z"K<Z W  
} 7%rSo^t,L  
/Mq]WXq[V  
D>& ;K{!  
//停止文件下载 -fF1vJ7L  
public void siteStop() r()%s3$q  
{ ]W,K}~!
 
bStop = true; a`}b'X:  
for(int i=0;i<nStartPos.length;i++) C N9lK29F)  
fileSplitterFetch.splitterStop(); m9*Lo[EXO  
\EH:FM}l,  
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} s3m]rC  
} ?h`Ned0P  
//负责部分文件的抓取 ibDMhW$n  
**FileSplitterFetch.java |&ISZFSv  
*/ F|._'i+B!  
package NetFox; GH%'YY3|  
(W~jr-O^  
)tQG5.to  
import java.io.*; e'<pw^I\  
import java.net.*; 6T%5vg_};'  
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public class FileSplitterFetch extends Thread { a/@<KnT  
Sz0M8fYT]  
e2#"o{+@  
String sURL; //File URL wv,,#P  
long nStartPos; //File Snippet Start Position XQEGMaZ  
long nEndPos; //File Snippet End Position |xI\)VE^  
int nThreadID; //Thread's ID OCy\aCp  
boolean bDownOver = false; //Downing is over bH7[6#
y$  
boolean bStop = false; //Stop identical 33d86H%;  
FileAccessI fileAccessI = null; //File Access interface K GlO;Q~7  
6T6 S9A*nT  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException '[shY  
{ _E5%Px5>L  
this.sURL = sURL; 2A3;#v  
this.nStartPos = nStart; \Cx) ~bq<  
this.nEndPos = nEnd; <YbOO{  
nThreadID = id; eqbxf#H!  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 l ' ]d&  
} yI9~LTlA3  
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\GtZX!0  
public void run() |(Zv g}c_  
{ '< OB j  
while(nStartPos < nEndPos && !bStop) S=O/W(ZB  
{ -&Fxg>FrYb  
2G"mm(   

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try{ U*8;ZXi  
URL url = new URL(sURL); 1E Lzzn  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); RMB?H)p+  
httpConnection.setRequestProperty("User-Agent","NetFox"); 9GS<d.#Nvc  
String sProperty = "bytes="+nStartPos+"-"; Cna@3)_  
httpConnection.setRequestProperty("RANGE",sProperty); dN>XZv  
Utility.log(sProperty); L1
u  
Auhw(b>}TW  
lo:]r.lX{  
InputStream input = httpConnection.getInputStream(); Du>dTi~  
//logResponseHead(httpConnection); yWIM,2x}  
8WWRKP1V  
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byte[] b = new byte[1024]; 'l\V{0;mp  
int nRead; gf+K
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while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 5EIhCbA  
{ ^SCZ  
nStartPos += fileAccessI.write(b,0,nRead); `>RJ*_aKEI  
//if(nThreadID == 1) HzB&+c?Z  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 76[aOC2Ad  
} /_rAy  
dQ^>,(  
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Utility.log("Thread " + nThreadID + " is over!"); CAY^ `K!  
bDownOver = true; c1wM"  
//nPos = fileAccessI.write (b,0,nRead); Kzxzz6R?  
} / /qTMxn  
catch(Exception e){e.printStackTrace ();} Vn1kC  
} _1*EMq6  
} c=H(*#  
.LafP}%  
f+0dwlIlC$  
//打印回应的头信息 iR4CY-  
public void logResponseHead(HttpURLConnection con) 9>psQ0IRvr  
{ 9QJ=?bIC#  
for(int i=1;;i++) >q <,FY!A  
{ NTiJEzW}  
String header=con.getHeaderFieldKey(i); '6{q;Bxo  
if(header!=null) 1W-t})!a  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); cWgiFv  
Utility.log(header+" : "+con.getHeaderField(header)); 9A\J*OU  
else VS^%PM#:/  
break; ,*0>CBJvv  
} YP~d1BWvf  
} IDzP<u8v  
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+IVVsVp
 
public void splitterStop() Kv+E"2d  
{ Z!6\KV]  
bStop = true; }"fP,:n"KN  
} $c0SWz  
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k(\HAIW  
} IGql^,b  
U*/  
a#!Vi93  
/* Q"
VFcp:  
**FileAccess.java >U"f1q*$  
*//文件访问(定位，写) .x6*9z#q  
package NetFox; +n9&q#ah  
import java.io.*; ^/R@bp#<  
-'{ioHt&X/  
DcoTa-~  
public class FileAccessI implements Serializable{ {^9,Dy_D  
PK3)M'[  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ci
5ERv`  
RandomAccessFile oSavedFile; 2DTH|Yv  
long nPos; Du$kDCU  
\ ;Hj,z\  
>?M:oUVDU  
public FileAccessI() throws IOException 
#x#.@  
{ $a\q<fN}  
this("",0); wx(|$2{h  
} NNutpA}s  
3-32q)8  
=DE5Wq19  
public FileAccessI(String sName,long nPos) throws IOException Ym&_IOx  
{ <3HW!7Ad1  
oSavedFile = new RandomAccessFile(sName,"rw"); l/LRr.x  
this.nPos = nPos; w[PW-m^`  
oSavedFile.seek(nPos); h'UWf"d  
} E(8!VY ^  
FO3!tJ\L  
z^~uq:  
public synchronized int write(byte[] b,int nStart,int nLen) S_c#{4n  
{ peGXU/5.I  
int n = -1; T>n,@?#K  
try{ 1$@k@*u\  
oSavedFile.write(b,nStart,nLen); GOH@|2N
  
n = nLen; 3KB)\nF#%  
} L)Un9&4L  
catch(IOException e) y+Q!4A  
{ p`{<q -  
e.printStackTrace (); Fxv~;o#  
} @Z@yI2#e  
!SiZA"  
<6p{eGAQV  
return n; QwOQS %  
} 6J
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/CKkT.Le  
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} Ofqe+C  
'.WYs!  
?]kIztH  
/* }kL%l  
**SiteInfoBean.java q7 Uu 8JXF  
*/ ?Dd2k%o  
package NetFox; hpWAQ#%oHm  
HW.S~eLw*  
qK|r+}g|&  
public class SiteInfoBean { A!iH g__/t  
gADt%K2#Z  
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private String sSiteURL; //Site's URL L=Dx$#|  
private String sFilePath; //Saved File's Path MrOW&7  
private String sFileName; //Saved File's Name .&r] ?O  
private int nSplitter; //Count of Splited Downloading File n0Ze9W+<  
e"^1- U\  
@!%<JZEz3  
public SiteInfoBean() e yTYg  
{//nSplitter的缺省值为5 P[XE5puC  
//default value of nSplitter is 5 \iowAo$  
this("","","",5); !nuXK  
} Q:_pW<^  
RG*Nw6A  
s%4)}w;z  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) .fo.mC@a  
{ Bu!Gy8\  
sSiteURL= sURL; CoJaVLl  
sFilePath = sPath; \,p)  
sFileName = sName; u#J5M&#  
this.nSplitter = nSpiltter; 1+#Vj#  
0C3Yina9 *  
Zpu>T2Tp  
} ml?+JbLg0  
V7rcnk#  
@gxO%@@  
public String getSSiteURL() V3@^bc!  
{ y0(k7D|\  
return sSiteURL; d9Rj-e1x  
} vNE91  
/ d6mlQS  
i7 p#%2  
public void setSSiteURL(String value) }b\d CGVr  
{ ;'gzRC  
sSiteURL = value; 9QY)<K~a  
} 4,$x~m`N  
|":^3  
b.Y[:R_9&  
public String getSFilePath() =9pFb!KX  
{ ;PS[VdV  
return sFilePath; uY
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} .6vQWt7@  
PFEi=}Y@((  
lX5(KUN
 
public void setSFilePath(String value) 0JNG\ARC  
{ d6hWmZVC  
sFilePath = value; Lk3@Eu)  
} (''`Ce  
3QV|@5L`[  
sF|<m)Kt{W  
public String getSFileName() zhN'@Wj'_  
{ Iupk
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return sFileName; b;x^>(It  
} bd)A6a\h  
sBRw#xyS  
,HMB
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public void setSFileName(String value) 4qyL' \d[  
{ 8swj'SjX  
sFileName = value; 2^UFP+Yw  
} ]^Q`CiKd  
x5PQ9Bw,  
_|6{(  
public int getNSplitter() w,`x(!&  
{ jr!x)yd  
return nSplitter; )C|>M'g@v  
} )}u.b-Nt.  
+(|T\%$DT  
n
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public void setNSplitter(int nCount) vkBngsS  
{ kTC6fNj[  
nSplitter = nCount; dAAE2}e  
} W"wP%  
} Keof{>V=CA  
v5<Ext rV  
t[an,3  
/* ^$x^JM ]/  
**Utility.java umls=iz  
*/ _/MKU!\l  
package NetFox; `7N[rs9|S  
C@Wm+E~;8  
MR+ndB<  
public class Utility { .[O*bk  
:_H$*Q=1  
Wb*d`hzQ}  
public Utility() pQEHWq"Q  
{ rcQ?E=V2O  
@+xkd(RfN  
WVwNjQ2PM  
} V (X)Qu@R  
EW]gG@w]5r  
//线程睡眠 J@yy2AZnO  
public static void sleep(int nSecond) Q) FL|  
{ [#2= w  
try{ Wigm`A=,r  
Thread.sleep(nSecond); /- kMzL  
} X8*q[@$  
catch(Exception e) y'E)iI*  
{ fNB*o={r|  
e.printStackTrace (); k92189B9j/  
} # <&=ZLN  
} \=83#*KK  
=2`s Uw}  
//日志 0]NsT0M  
public static void log(String sMsg) UGR5ILf  
{ b/S4b  
System.err.println(sMsg); ^M?uv
{354  
}
nTYqZlI,  
d~[>%&  
44_n5vp,T  
public static void log(int sMsg) M)3h 4yQ  
{ D;:lw]  
System.err.println(sMsg); ?rHc%H  
} pGsVO5M?  
} @rVmr{UE  
 '5[L []A  
Gm.v-T$  
/* l}<s~
ip  
**TestMethod.java #Q|$&b  
*/ u2U@Qrs2  
package NetFox; f Z\Ev%F  
|/r@z[t  
];Z_S`JR  
public class TestMethod { y
)(@  
/nC"'d(#  
I98wMV8  
public TestMethod() c?z%z&  
{ ///xx/weblogic60b2_win.exe JDMa
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try{ St&XG>nWS  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); j[Et+V?  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); eH1Y!&`  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 2gFQHV  
fileFetch.start(); J/ rQ42d  
} Uvz9x"0[u  
catch(Exception e){e.printStackTrace ();} H[6d@m- Z  
B;rq{ac!P]  
(1TYJ. Z  
} ^&Qaf:M  
{O!fV<Vx 9  
Cf%)W:Q9  
public static void main(String[] args) L(X:=) !K0  
{ s!UC{)g,  
new TestMethod(); X|.X4fs  
} /+66y=`UJ  
} /=-E`%R}!  
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