http断点续传简单实现（java)

/* T!+5[  
**SiteFileFetch.java {C=NUK%?  
*/ YVQN&|-  
package NetFox; BLfTsNzmt  
import java.io.*; *scVJ  
import java.net.*; JD)(oK%C  
<*16(!k0  
{> eXR?s/  
public class SiteFileFetch extends Thread { mn, =i  
}zkHJxZgE  
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SiteInfoBean siteInfoBean = null; //文件信息Bean I4/8 _)b^  
long[] nStartPos; //开始位置 "6MVvpy"  
long[] nEndPos; //结束位置 QdT}wkX  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 z>58dA@f  
long nFileLength; //文件长度 1"zDin!A  
boolean bFirst = true; //是否第一次取文件 _4"mAPt  
boolean bStop = false; //停止标志 0 HGM4[)=  
File tmpFile; //文件下载的临时信息 R.jIl@p   
DataOutputStream output; //输出到文件的输出流 sF!($k;!  
G_;)a]v8)  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） Sj]T   
public SiteFileFetch(SiteInfoBean bean) throws IOException GPkmf%FJ  
{ 2D75:@JL}|  
siteInfoBean = bean; E7t+E)=8  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 7!@-*/|!S9  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); QLXN*c  
if(tmpFile.exists ()) HG^B#yX  
{ .{ocV#{
s  
bFirst = false; jN{Xfjmfv  
read_nPos(); LPZF)@|`  
} V=R 3)GC  
else :[wsKFaV+  
{ +o\:d1y  
nStartPos = new long[bean.getNSplitter()]; F"&~*m^+  
nEndPos = new long[bean.getNSplitter()]; [B+yyBtx  
} JlH&??  
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} o<|cA5f\  
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public void run() Ov5"  
{ w`4=_J=GO  
//获得文件长度 7E!IF>`  
//分割文件 >6NRi/[  
//实例FileSplitterFetch rf $QxJ  
//启动FileSplitterFetch线程 o)Iff)m$  
//等待子线程返回 $;
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try{  3,p]/Z_  
if(bFirst) Rn}l6kbM  
{ gp5_Z-me  
nFileLength = getFileSize(); *,e:]!*  
if(nFileLength == -1) ]JCv
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{ zz+$=(T:M  
System.err.println("File Length is not known!"); KC/=TSSXd.  
} (\\eo  
else if(nFileLength == -2) r
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{ }Ga\wV  
System.err.println("File is not access!"); gRCdY8GH  
} 6g|*`x{  
else *!q1Kr6r  
{ C`$n[kCJ  
for(int i=0;i<nStartPos.length;i++) l n{e1':$"  
{ 8K.R=  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); `P@T$bC  
} #bUXgn>  
for(int i=0;i<nEndPos.length-1;i++) A0o-:n Fu  
{ 1Yq?X:   
nEndPos = nStartPos[i+1]; Gr7=:+0n|P  
} e5*ni/P  
nEndPos[nEndPos.length-1] = nFileLength; S]bmS6#  
} gW^VVbB'L  
} Yk)."r
&?  
w$+&3t  
a6D &/8  
//启动子线程 q;R],7Re  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ;|pBFKx  
for(int i=0;i<nStartPos.length;i++) ,=UK}*e"  
{ }T; P~aG  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Tu
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), WlB  
nStartPos,nEndPos,i); b<a4'M  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 24E}<N,g  
fileSplitterFetch.start(); /JFUU[W  
} + ,%&e  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), B|R@5mjm  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ZjgsR|i  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", I%r{]-Obr-  
nEndPos = " + nFileLength); JG" R\2  
// fileSplitterFetch[nPos.length-1].start(); R@/"B8H  
5 xppKt  
6N",-c  
//等待子线程结束 I/a/)No  
//int count = 0; 8D>n1b(H  
//是否结束while循环 :# .<[  
boolean breakWhile = false; u])b,9&En  
W~zbm]  
TOkp%@9/
 
while(!bStop) le1}0L  
{ C69q&S,  
write_nPos(); N!ls j \-  
Utility.sleep(500); P#RR9>Q  
breakWhile = true; 'JCZ]pZ  
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for(int i=0;i<nStartPos.length;i++) Z1 Bp+a3  
{ MXw hxk#E  
if(!fileSplitterFetch.bDownOver) b6Wqr/  
{ byLft1  
breakWhile = false; ;*
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break; oE+R3[D?r  
} {l>yi  
} B.dH(um  
if(breakWhile) Of"  
break; %5eY'  
-&3hEv5  
4?ICy/,U-  
//count++; gLE:g5v6  
//if(count>4) X.Rb-@  
// siteStop(); /JHc!D  
} Jz7!4mu  
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System.err.println("文件下载结束！"); qyF{f8pzq  
} luo  
catch(Exception e){e.printStackTrace ();} vd[}Gd  
} ]~aF2LJ_q  
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//获得文件长度 g'H$R~ag  
public long getFileSize() ^su<uG<R  
{ jzDuE{  
int nFileLength = -1; d Vj_8>  
try{ z2g3FUTX)b  
URL url = new URL(siteInfoBean.getSSiteURL()); tKuVQH~D  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); yKa{08X:  
httpConnection.setRequestProperty("User-Agent","NetFox"); z.kvX+7'  
(BTVD,G  
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int responseCode=httpConnection.getResponseCode(); #:[t^}  
if(responseCode>=400) qv]}$WU  
{ bmfI~8  
processErrorCode(responseCode); ' 0J1vG~c  
return -2; //-2 represent access is error {[+mpKq
 
} vhpNpgz  
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VHCK2}ps  
String sHeader; np8gKVD  
|C!oxhu<  
#73F} tZ^  
for(int i=1;;i++) i.3=!6z  
{ Nd$W0YN:  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); <,[cQ
I/  
//Utility.log(in.readLine()); J%x\=Sv  
sHeader=httpConnection.getHeaderFieldKey(i); BQ=PW|[  
if(sHeader!=null) E^vJ@O  
{ .}OR  
if(sHeader.equals("Content-Length")) _a6[{_Pc  
{ ~yH?=:>U  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); swM*k;$q{  
break; q(`/Vo4g(  
} rEB@$C^  
} P(+&OoY2  
else RloK,bg  
break; n?- })  
} {so`/EWa  
} &
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catch(IOException e){e.printStackTrace ();} 3BtaH#ZY  
catch(Exception e){e.printStackTrace ();} bn!HUM,
  
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Utility.log(nFileLength); ,.kha8v  
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return nFileLength; M luVx'  
} :cF[(i/k4  
/atW8 `&  
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//保存下载信息（文件指针位置） /ro=?QYb  
private void write_nPos() m9.{[K"  
{ ] lrWgm  
try{ n[G&ksQI  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 2/"u
5  
output.writeInt(nStartPos.length); IIn"=g=9  
for(int i=0;i<nStartPos.length;i++) G/7cK\^u  
{ IOqwC
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// output.writeLong(nPos); xx#zN0I>-y  
output.writeLong(fileSplitterFetch.nStartPos); `< xn8h9p  
output.writeLong(fileSplitterFetch.nEndPos); "|qqUKJZ  
} orWbU UC  
output.close(); ;[M}MFc/`  
} 9f&C  
catch(IOException e){e.printStackTrace ();} >pp5;h8!  
catch(Exception e){e.printStackTrace ();} "nw;NIp!  
} b[o"7^H  
OmIg<v0\;  
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//读取保存的下载信息（文件指针位置） ll`>FcQ  
private void read_nPos() uBNn6j  
{ 23RN}LUi  
try{ Rm255zp  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); -uMSe~  
int nCount = input.readInt(); 3|'>`!hb  
nStartPos = new long[nCount]; #~C]ZrK  
nEndPos = new long[nCount]; xI($Uu}S  
for(int i=0;i<nStartPos.length;i++) /5Oa,NS7  
{ 1*9U1\z  
nStartPos = input.readLong(); }]lr>"~y}  
nEndPos = input.readLong(); L"o>wYx
 
} kXi6lh  
input.close(); B?'#4J  
} =;2%a(  
catch(IOException e){e.printStackTrace ();} {L/tst#C  
catch(Exception e){e.printStackTrace ();} Y@N,qHtz  
} SqEgn}m$  
-jb0o/:  
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private void processErrorCode(int nErrorCode) Wu[&Wv~  
{ { g/0x,-Z  
System.err.println("Error Code : " + nErrorCode); /v-6WSN  
} }\\KYyjY  
_'{_gei_P  
@?yX!_YC  
//停止文件下载 ]yK7PH-{L  
public void siteStop() BG6B:  
{ OY;*zk  
bStop = true; AiEd!u.  
for(int i=0;i<nStartPos.length;i++) ~Y|*`C_)  
fileSplitterFetch.splitterStop(); @mw5~+  
k <=//r  
ca7=V/i_a{  
} ;7?kl>5]  
} wt!nMQ  
//负责部分文件的抓取 /s@oZ{h  
**FileSplitterFetch.java VyzS^AHK  
*/ [RLN;(0n  
package NetFox; =5/9%P8j9  
8<8:+M}  
pTPi@SBaP{  
import java.io.*; lI*o@wQg  
import java.net.*; !F A]  
x:),P-~w  
m[~V/N3  
public class FileSplitterFetch extends Thread { Xejo_SV&?  
>qS9PX  
8Kg n"M3  
String sURL; //File URL 3I)VHMC  
long nStartPos; //File Snippet Start Position D~
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long nEndPos; //File Snippet End Position (tIo:j  
int nThreadID; //Thread's ID gy#/D& N[  
boolean bDownOver = false; //Downing is over 3RYpJAH  
boolean bStop = false; //Stop identical OBOtuu.  
FileAccessI fileAccessI = null; //File Access interface p"n$!ilbm  
9 7GV2]-M  
=t9\^RIx)?  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Cs9.&Y  
{ /fZeWU0W  
this.sURL = sURL; jcuB  
this.nStartPos = nStart; k5:G-BQ:  
this.nEndPos = nEnd; 9 Vkb>yFX'  
nThreadID = id; 'p>Ra/4  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 mZSD(  
} sf)EMh3Z  
L ^q""[  
=G7m)!  
public void run() cq}EZ@ .  
{ }uJu>'1
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while(nStartPos < nEndPos && !bStop) *5%d XixN  
{ [x+FcXb  
+S>j0m<*  
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try{ d:BG#\e]v  
URL url = new URL(sURL); >,F bX8Zz  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); }&cu/o4  
httpConnection.setRequestProperty("User-Agent","NetFox"); (gP)%  
String sProperty = "bytes="+nStartPos+"-"; @;*Ksy@1O  
httpConnection.setRequestProperty("RANGE",sProperty); Y$Zx,  
Utility.log(sProperty); ,K9*%rW)  
9oYgl1}d  
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InputStream input = httpConnection.getInputStream(); /N=b\-]  
//logResponseHead(httpConnection); fmU {  
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byte[] b = new byte[1024]; L2\#w<d  
int nRead; U'H$`$Ov  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ?9e_gV{&;  
{ $xzAv{  
nStartPos += fileAccessI.write(b,0,nRead); ojcA<60 '  
//if(nThreadID == 1) [tlI!~Z  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); NjVYLn<.r  
} 7j@Hs[
*  
f(/lLgI(  
z[b@V  
Utility.log("Thread " + nThreadID + " is over!"); nV"~-On  
bDownOver = true; B^4&-z2|  
//nPos = fileAccessI.write (b,0,nRead); /rK}?U  
} ?qPo=~y01  
catch(Exception e){e.printStackTrace ();} [%q@]\U$s  
} Ro\8ZXUQa  
} ;rF\kX&Jh  
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//打印回应的头信息 ;O,+2VzP%^  
public void logResponseHead(HttpURLConnection con) '*K:  lx  
{ NP0\i1P>.?  
for(int i=1;;i++) sd*p/Q|4  
{ w mn+  
String header=con.getHeaderFieldKey(i); c/D+|X*  
if(header!=null) umjt]Gu[  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); y&6FybIz  
Utility.log(header+" : "+con.getHeaderField(header)); Vx$\hcG  
else {x|[p_?  
break; Njxv4cc  
} m4**~xfC  
} h{CL{>d  
<`.X$r*  
U_M$#i{_  
public void splitterStop() =m!-m\B/  
{ |z9*GY6RU  
bStop = true; caU0\VS  
} fa-IhB1!K  
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} 3-[q4R  
'H3^e}   
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/* P0SQr?W  
**FileAccess.java VQ(jpns5  
*//文件访问(定位，写) };mA^xO]j  
package NetFox; t#V!8EpBg  
import java.io.*; 0g +7uGp:  
h`]I
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public class FileAccessI implements Serializable{ oL!EYbFD'Z  
,-$LmECg  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 $ZUdT  
RandomAccessFile oSavedFile; PxTwPl  
long nPos; ?}Z1bH  
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public FileAccessI() throws IOException "An,Q82oHf  
{ Z)e/!~""]  
this("",0); +M./@U*g  
} Y#]+Tm(+  
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public FileAccessI(String sName,long nPos) throws IOException XtXEB<4Z  
{ ,MdV;j~"'  
oSavedFile = new RandomAccessFile(sName,"rw"); Rvkedb  
this.nPos = nPos; 8{|8G-Mi  
oSavedFile.seek(nPos); }'5MK  
}
10G}{  
rK@8/?y5  
fWCo;4<5?  
public synchronized int write(byte[] b,int nStart,int nLen) !lREaSM  
{ ;PF`Wj  
int n = -1; q YC;cKv  
try{ wc0jhHZO ?  
oSavedFile.write(b,nStart,nLen); }^4Xv^dW>g  
n = nLen; QgrpBG  
} KLU-DCb%  
catch(IOException e) =
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{ 00<cYy
  
e.printStackTrace (); d4m=0G`  
} x
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return n; +y,T4^{  
} eiuSvyY  
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} 'UkxS b  
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/* T\:4qETQF]  
**SiteInfoBean.java 7@C<oy_bb  
*/ x9NEFtqjm  
package NetFox; ".f ;+wH  
xpNH?#&  
iF*:d  
public class SiteInfoBean { -Q2, "  
cy*?&~;  
*EI6dD"  
private String sSiteURL; //Site's URL DDvh4<
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private String sFilePath; //Saved File's Path 'z );  
private String sFileName; //Saved File's Name TvwZW!@jc  
private int nSplitter; //Count of Splited Downloading File SEORSS  
S,D8F&bg  
"lQ*1.i  
public SiteInfoBean() ?M$.+V{a  
{//nSplitter的缺省值为5 FRcy`)  
//default value of nSplitter is 5 Twh!X*uQ  
this("","","",5); @)IjNplYkw  
} r}Ohkr  
J%8(kWQ|  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) g6nkZyw  
{ K7$x<5+)  
sSiteURL= sURL; yZd +^QN  
sFilePath = sPath; H!vax)%-\  
sFileName = sName; xE1 eT,  
this.nSplitter = nSpiltter; |yvQ[U~PQ  
&vHoRY  
w|3z;-#Q;  
} L%">iQOG#  
P<oehw'>  
S(QpM.9*  
public String getSSiteURL() }p=Jm)y  
{ ,?PTcQF  
return sSiteURL; %el"BSB  
} YpQ7)_s?  
U2$d%8G  
|\w=u6jX  
public void setSSiteURL(String value) ^*S ,xP  
{ wU8Mt#D!  
sSiteURL = value; ADZ};:]  
} ~a%Z;Aj  
~7Y+2FZ  
V=)_yIS  
public String getSFilePath() jNe`;o  
{ 8m5p_\&  
return sFilePath; P D4Tz!F  
} $ oTdfb  
NHB4y/2  
SH3|sXH<  
public void setSFilePath(String value) 9Kr+\F  
{ r$5i Wu  
sFilePath = value; .#wqXRd  
} lT4Hn;tnN  
 rL/H2[d  
|]QqXE-7  
public String getSFileName() Mc#*wEo)8  
{ _,q)hOI  
return sFileName; 2#o>Z4 r{  
} $m7?3/YG  
f @8mS   
cbeLu'DWB.  
public void setSFileName(String value) #u2J;9P  
{ vQ<90ZxqB  
sFileName = value; DQMHOd7g  
} cQG +$0(  
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public int getNSplitter() 0$_oT;{8  
{ YiYV>gaf"H  
return nSplitter; vK(i9>;7  
} 5pU2|B
k /  
~i@Y|38C  
-DxL0:E  
public void setNSplitter(int nCount) -<Hu!V`+  
{ C(S'#cm  
nSplitter = nCount; 1<+2kBuY  
} kR]!Vr*yh  
} )=\#UE+W  
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m1n.g4Z&*  
/* W-Fu-Cz=  
**Utility.java ZPc@Zr`z  
*/ }>)@WL:q  
package NetFox; lJ+0P2@h*  
x8!ol2\`<  
^BUYjq%(`  
public class Utility { c;{Q,"9U  
yvgrIdEP  
QF-LU  
public Utility() UUF;p2{f  
{ ub7zA!%  
6UevpDB  
[(o7$i29|%  
} h\7fp.  
cKN$ =gd  
//线程睡眠 ex+\nD>t4  
public static void sleep(int nSecond) Wqc)Fv70m  
{ o]Ol8I  
try{ D,;\o7V  
Thread.sleep(nSecond); wtmB+:I  
} O_cbP59Y.  
catch(Exception e) ?gJOgsHJP  
{ V~S0hqW[  
e.printStackTrace (); 0OT\"O~S[  
} ~ns7O  
} T(AVlI6  
klQC2drS  
//日志 iS&l8@2a  
public static void log(String sMsg) )>b.;  
{ 0ge$ p,  
System.err.println(sMsg); \=+b}mKV m  
} )foq),2  
hdnTXs@z  
ET_W-  
public static void log(int sMsg) N+LL@[  
{ =1O
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System.err.println(sMsg); O$D'.t  
} iv?gZg   
} k=4N(i/s  
\ {qI4=  
xfy1pS.[:  
/* a^Tmu  
**TestMethod.java |fxA|/s[<  
*/ RaWG w  
package NetFox; lrWV#`6!+  
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5nTY ?<x`k  
public class TestMethod { *?y+e  
?6
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6 `Aj%1  
public TestMethod() "
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{ ///xx/weblogic60b2_win.exe F^N82  
try{ ]Pry>N3G5  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); h@:TpE+N  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); {88gW\GL  
SiteFileFetch fileFetch = new SiteFileFetch(bean); AX?fuDLs  
fileFetch.start(); I8+~ &V}  
} [cTe54n  
catch(Exception e){e.printStackTrace ();} %STliJ  
%|^OOU}  
)x}l3\s  
} *<E]E?  
/&CmO>^e  
d)@<W1;  
public static void main(String[] args) G P:FSprP  
{ ?."&MZ  
new TestMethod(); $U$V?xuE  
} |+35y_
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} gXonF'  
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