http断点续传简单实现（java)

/* qj?I*peK)  
**SiteFileFetch.java _j<,qi  
*/ OL[_2m*;9p  
package NetFox; q{.~=~  
import java.io.*; %;G!gJeE  
import java.net.*; 2K'}Vm+  
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public class SiteFileFetch extends Thread { {K2F(kz?T  
,@2d4eg4  
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SiteInfoBean siteInfoBean = null; //文件信息Bean JDC,]  
long[] nStartPos; //开始位置 "(?[$R  
long[] nEndPos; //结束位置 wT\dzp>/  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 F^');8~L  
long nFileLength; //文件长度 @yjui  
boolean bFirst = true; //是否第一次取文件 #/pZ#ny  
boolean bStop = false; //停止标志 II_MY#0X  
File tmpFile; //文件下载的临时信息 Ia)
^  
DataOutputStream output; //输出到文件的输出流 *$>$O%  
k?=V?JWY
 
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） Iyvl6  
public SiteFileFetch(SiteInfoBean bean) throws IOException SHPZXJ{  
{ \'N|1!EO|t  
siteInfoBean = bean; Bb/aeLv  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); jN
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tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); YJwz*@l  
if(tmpFile.exists ()) 8%9OB5?F6  
{ %K]nX#.B&  
bFirst = false; 0b}lwo,|\  
read_nPos(); ?)5M3lV3k  
} ';7|H|,F
 
else 8 _[f#s`)  
{ Qod2m$>wp}  
nStartPos = new long[bean.getNSplitter()]; c[0$8F>  
nEndPos = new long[bean.getNSplitter()]; z'X_s.9F  
} !PrO~  

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} P.1iuZ "w  
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public void run() VVje|T^{Z  
{ }fs;yPl,  
//获得文件长度 |wj/lX7y  
//分割文件 >Y< y]vM:  
//实例FileSplitterFetch 2jx+q  
//启动FileSplitterFetch线程 z95V 7E  
//等待子线程返回 K+mtuB]yr  
try{ Qi7^z;  
if(bFirst) ,K6]Q|U@r  
{ {1YT a:evl  
nFileLength = getFileSize(); 0?t!tugG  
if(nFileLength == -1) @w:sNX
z-  
{ BmUzsfD  
System.err.println("File Length is not known!"); Xc5[d`]  
} ig/716r|  
else if(nFileLength == -2)
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{ Sb[rSczS~  
System.err.println("File is not access!"); @;,O V&XYn  
} 0+:.9*g=k  
else @]#+`pZ4A  
{ x{*!"a>  
for(int i=0;i<nStartPos.length;i++) S8vmXlD  
{ ?\F,}e  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); {nOK*7+"  
} @+X}O/74  
for(int i=0;i<nEndPos.length-1;i++) r5iO%JFg  
{ I}v'n{5(  
nEndPos = nStartPos[i+1]; )3B5"b,  
} n7q-)Dv_U  
nEndPos[nEndPos.length-1] = nFileLength; ?3z+|;t6C  
} 3]Lk}0atpL  
} A1ebXXD)  
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//启动子线程 #CQ>d8&  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Yhw* `"X  
for(int i=0;i<nStartPos.length;i++) khv!\^&DD  
{ X-{:.9  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), BK d(  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), \ bT]?.si  
nStartPos,nEndPos,i); EJtU(HmW  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Z#MODf0H@  
fileSplitterFetch.start(); 'HcDl@E  
} JN KZ'9  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), F5<{-{Ky  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); LMG\jc?,  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", M<~F>(wxA  
nEndPos = " + nFileLength); NxX1_d  
// fileSplitterFetch[nPos.length-1].start(); )#ujF~w>  
Gj_b GqF8}  
#=.h:_9  
//等待子线程结束 -X}R(.}x  
//int count = 0; ,m b3H  
//是否结束while循环 VDmd+bvJV  
boolean breakWhile = false; c\b>4 &n  
 xBG1up<z  
!3&v
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while(!bStop) 1aT$07G0  
{ d|NNIf  
write_nPos(); "DN`@  
Utility.sleep(500); 3CHte*NL=  
breakWhile = true; QF>[cdl?8  
'Lw\nO.  
 zm.2L  
for(int i=0;i<nStartPos.length;i++) 86I*
 
{ 0?h .X=G  
if(!fileSplitterFetch.bDownOver) (_08?cN  
{ jw[`_  
breakWhile = false; O46/[{p+8  
break; vZDQ@\HrC  
} ,`7GI*Vq  
} 5
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if(breakWhile) >PJ-Z~O'   
break; 5k(#kyP  
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E0pQRGPA  
//count++; t]o gn(  
//if(count>4) Bm7GU
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// siteStop(); '} kq@  
} r/T DU[`&  
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^9RBG#ud  
System.err.println("文件下载结束！"); g0U ?s  
} z} \9/`  
catch(Exception e){e.printStackTrace ();} rN~`4mZ  
} By_Ui6:D  
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D?'y)](  
//获得文件长度 R`&ioRWj  
public long getFileSize() J?<L8;$s
7  
{ L' pZ  
int nFileLength = -1; ({9!P30:  
try{ ?f`-&c;  
URL url = new URL(siteInfoBean.getSSiteURL()); ^Bb_NcU  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); HW G~m:km  
httpConnection.setRequestProperty("User-Agent","NetFox"); `+o.w#cl  
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int responseCode=httpConnection.getResponseCode(); u@EM,o  
if(responseCode>=400) {EUH#':  
{ D.6dPzu`  
processErrorCode(responseCode); \}=b/FL=U  
return -2; //-2 represent access is error p o`$^TB^+  
} lBdF9F<  
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String sHeader; I@ k8
^  
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for(int i=1;;i++) ;^*!<F%t9R  
{ `Vi:r9|P  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); iPOZ{'Z  
//Utility.log(in.readLine()); ka3Z5  
sHeader=httpConnection.getHeaderFieldKey(i); 8TPm[r]  
if(sHeader!=null) K
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{ ]EnaZWyO]  
if(sHeader.equals("Content-Length")) w0!,1 Ry  
{ ]t3"0  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); g4X,*H  
break; #U}U>4'  
} ,
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} WL
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else %}!}2s.A  
break; n4 @a`lN5g  
} (<Xdj^v  
} C(|5,P#5  
catch(IOException e){e.printStackTrace ();} ,9qB}HG  
catch(Exception e){e.printStackTrace ();} U
08?*{  
vWH>k+9&X  
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Utility.log(nFileLength); RKkI/Z0  
yp^*TD/J  
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return nFileLength; B,833Azi  
} Zg&\K~OC  
d6EY'*0  
Bedjw =B  
//保存下载信息（文件指针位置） B?yt%f1  
private void write_nPos() :(`>bY  
{ C
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try{ ~bTae =FP  
output = new DataOutputStream(new FileOutputStream(tmpFile)); -<!17jy  
output.writeInt(nStartPos.length); 1>VS/H`  
for(int i=0;i<nStartPos.length;i++) p8dn-4  
{ X);Zm7  
// output.writeLong(nPos); ON0+:`3\  
output.writeLong(fileSplitterFetch.nStartPos); Q;/F0JDH  
output.writeLong(fileSplitterFetch.nEndPos); Ch9!AUiR  
} O + & xb  
output.close(); !(K{*7|h  
} b6vYM_ Q  
catch(IOException e){e.printStackTrace ();} `;CU[Ps?]  
catch(Exception e){e.printStackTrace ();} 7$W;4!BN*  
} .p(l+  
f<:U"E.  
KBR0p&MN  
//读取保存的下载信息（文件指针位置） ;Ph)BY<  
private void read_nPos() Lu39eO6  
{ -==qMrKP  
try{ dm=F:\C  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); t}k'Ba3]:Y  
int nCount = input.readInt(); gQ[^gPWP"  
nStartPos = new long[nCount]; IWo~s  
nEndPos = new long[nCount]; N"RYM~c7  
for(int i=0;i<nStartPos.length;i++)  'Q>z**  
{ psX%.95Y  
nStartPos = input.readLong(); G=HxD4l  
nEndPos = input.readLong(); NJf(,Mr*|  
} ,Kf8T9z`  
input.close(); -wQ^oOJ  
} J%:/<uCmZ  
catch(IOException e){e.printStackTrace ();} ]esLAo  
catch(Exception e){e.printStackTrace ();} Gj19KQ1G  
} +`zi>=  
L1kM~M  
#2R%H.*t  
private void processErrorCode(int nErrorCode) w<e;rKr  
{ =l4\4td9p  
System.err.println("Error Code : " + nErrorCode); K6{bYho  
} 4ylDD|) rO  
(}1v^~FXj  
`m3QT3B  
//停止文件下载 p?$G>nkdq  
public void siteStop() R:OU>HsdX  
{ NJ)2+  
bStop = true; 3
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for(int i=0;i<nStartPos.length;i++) 04PoBv~g  
fileSplitterFetch.splitterStop(); .k,Jt+  
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} /;NE]{K  
} ~8xh0TSi  
//负责部分文件的抓取 +lgF/y6  
**FileSplitterFetch.java gMBQtPNM  
*/ CQjZAv  
package NetFox; 4m~7 ~-h  
Y3$PQwn .P  
25a#eDbqi  
import java.io.*; gO:Z6}3vM  
import java.net.*; 'uf2 nUo  
^jha:d  
9c^skNbS  
public class FileSplitterFetch extends Thread { ,3]?%t0xe  
D<bU~Gd,P  
.D,?u"fk|  
String sURL; //File URL [Ba2b: l6v  
long nStartPos; //File Snippet Start Position W`u$7k]$  
long nEndPos; //File Snippet End Position {LT4u]#  
int nThreadID; //Thread's ID _TOi [GT  
boolean bDownOver = false; //Downing is over :-u-hO5*8  
boolean bStop = false; //Stop identical G?-`>N-u  
FileAccessI fileAccessI = null; //File Access interface G?1x+H;o5  
S -
6"f/  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ~+<xFi  
{ U8K&Q4^  
this.sURL = sURL; dT]L-uRZgy  
this.nStartPos = nStart; !jAWNK6  
this.nEndPos = nEnd; jj3Pf>D+k  
nThreadID = id; Q&upxE4-~  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 <DXmZ1  
} }*.:Hv"  
j!S1Y0CV  
'l' X^LMD  
public void run() 0n*rs=\VG  
{ VZ2.w4b  
while(nStartPos < nEndPos && !bStop) ByhOK}u;P4  
{ h7EUIlh"  
7~ *;=,mw  
a*6wSAA )  
try{ R5K-KSvW  
URL url = new URL(sURL); R2N^'  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection ();
13.{Y)  
httpConnection.setRequestProperty("User-Agent","NetFox"); i0'Xy>l  
String sProperty = "bytes="+nStartPos+"-"; U+.PuC[3  
httpConnection.setRequestProperty("RANGE",sProperty); .>kccLr:z  
Utility.log(sProperty); a:yB%:2  
XhE$&Ff  
np-T&Pz2  
InputStream input = httpConnection.getInputStream();
K}PvrcO1  
//logResponseHead(httpConnection); :'d76pM-  
emv;m/&8  
BH&/2tO%  
byte[] b = new byte[1024]; <Spr6U9p7  
int nRead; QJ a4R  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) hGed/Yr  
{ B:O+*3j  
nStartPos += fileAccessI.write(b,0,nRead); [xtK"E#  
//if(nThreadID == 1) 8Wdkztp/S  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Ii~; d3.  
} 
n5bXQ  
#)_J)/h  
_8[UtZYG  
Utility.log("Thread " + nThreadID + " is over!"); ^e?$ ]JiA!  
bDownOver = true; F2bm+0vOJ  
//nPos = fileAccessI.write (b,0,nRead); e86Aqehle  
} 'bB>$E  
catch(Exception e){e.printStackTrace ();} Mx/h?}u;  
} |.b%rVu  
} .W$ sxVXB  
(oF-O{  
0:. 6rp  
//打印回应的头信息 ( :iPm<  
public void logResponseHead(HttpURLConnection con) c88_}%h?(  
{ 8|6~o.B.G  
for(int i=1;;i++) r( M[8@Nz  
{ B7|c`7x(  
String header=con.getHeaderFieldKey(i); -rO*7HO
 
if(header!=null) 5:$Xtq  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); n6/fan;  
Utility.log(header+" : "+con.getHeaderField(header)); fL2^\dB;  
else !f`5B( @  
break; [$;,Ua-mt  
} W=3? x  
} V;k#})_-  
o~;M"  
@*SA$9/l  
public void splitterStop() 2Q}7fht  
{ z#RuwB+  
bStop = true; w]F!2b!  
} /w0w*nH  
,aWCiu}  
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} t?HF-zQ  
}YRO'Q{  
hox< vr4  
/* -qfnUh  
**FileAccess.java $,@JYLC2  
*//文件访问(定位，写) >%l:Dw\A:
 
package NetFox; oJh"@6u6K  
import java.io.*; TVYz3~m  
e:BDQU  
;5N41_hG  
public class FileAccessI implements Serializable{ ^;4YZwW5w  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ncj!KyU  
RandomAccessFile oSavedFile; #hy
+ L  
long nPos; AC'lS >7s  
>P<'L4;  
zC#%6@P\  
public FileAccessI() throws IOException qEZ!2R^`G  
{ 1LX)4TCC  
this("",0); ~XKZXGw  
} EWO /u.z  
@%:E }  
kf'=%]9#_T  
public FileAccessI(String sName,long nPos) throws IOException @+E7w6>%  
{ 6^ab@GrN\  
oSavedFile = new RandomAccessFile(sName,"rw"); 83Uw  
this.nPos = nPos; *x!LKIpv  
oSavedFile.seek(nPos); UhdqY]  
}
:T5A84/C  
Fo(y7$33*  
uRpBeH]Z"  
public synchronized int write(byte[] b,int nStart,int nLen) E?_ zZ2  
{ ;P8(Zf3wJb  
int n = -1; ~2(]ZfO?>H  
try{ ;t!9]1  
oSavedFile.write(b,nStart,nLen); >8(jW  
n = nLen; 'B,KFA<
 
} {"t5\U6cKM  
catch(IOException e) \FXp*FbQ  
{ ~?d>fR:X  
e.printStackTrace (); ;Yv14{T!  
} hJLT!33:  
Qh8C,"a  

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return n; 8jNOEM(0Y+  
} Z0W0uP;J  
2LC w*eT{)  
#QS?s8IrW  
} C99&L3bz^(  
%{"dP%|w4}  
kIX)oD}c  
/* 86qcf"?E  
**SiteInfoBean.java 3daC;;XO  
*/ :X Lp  
package NetFox; 2lo:a{}j  
|EEi&GOR(y  
QXY}STs  
public class SiteInfoBean { x)5LT}p  
kV+ R5R  
MyFCJJ/  
private String sSiteURL; //Site's URL _ Mn6L=  
private String sFilePath; //Saved File's Path z37Z%^  
private String sFileName; //Saved File's Name
-;/ Y  
private int nSplitter; //Count of Splited Downloading File \%4|t,en  
h$/JGm5uDb  
H?{MRe  
public SiteInfoBean() Yt*vqm[WV  
{//nSplitter的缺省值为5 4DM*^=9E  
//default value of nSplitter is 5 d- kZt@DL=  
this("","","",5); OpUA{P  
} lQ$+JX;n(y  
1$(  
$+jy/:]D  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) |6*Va%LYO-  
{ {=iyK/Uf  
sSiteURL= sURL; O2lIlCL  
sFilePath = sPath; }lO }x  
sFileName = sName; 4 4`WYK l  
this.nSplitter = nSpiltter; |]tZ hI"3<  
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,J&9kYz  
} 7>&1nBh. f  
yW`e |!  
R{`gR"*  
public String getSSiteURL() =x#&\ui  
{ dm& /K 4c  
return sSiteURL; 3HKxYvc C  
} WGMb8 /{$P  
s`1^*Dl%+  
u>}zm_  
public void setSSiteURL(String value) t)'dF*L  
{ .pW o>`"  
sSiteURL = value; y!hi"!  
} LuL$v+`  
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public String getSFilePath() }Aw47;5q;  
{ 3a^)u-9,x  
return sFilePath; [S)G$JW  
}
}<&d]N  
BfVBywty  
O]bKNA.5  
public void setSFilePath(String value) f:XfAH3R{  
{ X|Dpt2A=  
sFilePath = value; 0e\y~#-  
} j/' g$  
s>r ^r%uK  
z{/LX \  
public String getSFileName() )mG0g@qOK  
{ )ji@k(x27q  
return sFileName; D:)~%wu Lt  
} OEI3eizgH  
y;r"+bS8  
#<]Iz'\`  
public void setSFileName(String value) Wp`C:H  
{ 3C#RjA-2[  
sFileName = value; zb?kpd}r  
}
2NYi-@mr  
"
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public int getNSplitter() %ZiK[e3G  
{ Q.1XP  
return nSplitter; E|{m"RUOy  
} ^}@`!ON  
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Bz:&f46{  
public void setNSplitter(int nCount) AA2ui%  
{ y{9
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nSplitter = nCount; BCBUb  
} (V)9s\Le_  
} pND48 g;  
)vQNiik#  
aP_3C_  
/* &#-[Y:?lA  
**Utility.java ?yf_Dt  
*/ =E1tgrW  
package NetFox; {KsVK4\r  
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public class Utility { @7-D7  
WAv@F[  
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public Utility() NZfd_? 3  
{ 'QR4~`6I  
ET3,9+Gj  
=EWD |<  
} /cYk+c  
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//线程睡眠 PF`:1;PU  
public static void sleep(int nSecond) RPY6Wh|4  
{  tI'e ctn  
try{ 7BS/T  
Thread.sleep(nSecond); F=:c5z  
} 'f8 p7_F  
catch(Exception e)
],AbcTX  
{ [?|5oaK  
e.printStackTrace (); g4Bg6<;  
} gkLr]zv  
} B]i+,u  
-: C[P  
//日志 il7!}  
public static void log(String sMsg) a0 qj[+  
{ pRmEryR(U  
System.err.println(sMsg); sY_fq
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} aC4m{F[  
pIL`WE1'  
*6'_5~G  
public static void log(int sMsg) hl}dgp((  
{ /lru"R D  
System.err.println(sMsg); x7Eeb!s0f,  
} n
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} WVj&0  
^T=5zqRD  
bnIf}ut-G  
/* ,znL,%s  
**TestMethod.java gl Li  
*/ 8XgVY9]Qm  
package NetFox;  eMztjN  
1/!nV  
Qve`k<Cj"  
public class TestMethod { K:C+/O  
7~:>WMv
9  
Kgps_tY%  
public TestMethod() Gtf1}UJC  
{ ///xx/weblogic60b2_win.exe 2
e)  
try{ gZ=)qT]Pj  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ;wfH^2HxE)  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); :LG}yq^  
SiteFileFetch fileFetch = new SiteFileFetch(bean); YK7
gd|LR]  
fileFetch.start(); Ed4_<:  
} x>'?IJZ  
catch(Exception e){e.printStackTrace ();} /\Jc:v#Q  
+38Lojb}  
Sv~PXi^`H  
} 4D0(Fl  
?|\0)wrRf  
WReYF+Uen  
public static void main(String[] args) 65 NWX8f}  
{ J*/$ywI  
new TestMethod(); ;I[.  
} zjzqKdy}F  
} @:I\\S@bN  
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