http断点续传简单实现（java)

/* X&X')hzIt  
**SiteFileFetch.java oe"ShhT  
*/ d's`~HOU2  
package NetFox; *3Z#r  
import java.io.*; tTp`e0L*m  
import java.net.*; XhV"<&v  
O#Hz5A5  
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public class SiteFileFetch extends Thread { 4jro4B`  
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SiteInfoBean siteInfoBean = null; //文件信息Bean /*HSAjv  
long[] nStartPos; //开始位置 m
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long[] nEndPos; //结束位置 L$Z_j()2  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 nzl,y,  
long nFileLength; //文件长度 p:%E>K1<  
boolean bFirst = true; //是否第一次取文件 ^ ?9 ~R"  
boolean bStop = false; //停止标志 XX6)(  
File tmpFile; //文件下载的临时信息 5]%kWV>  
DataOutputStream output; //输出到文件的输出流 %&(\dt&R1h  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 3l[hkRFu`  
public SiteFileFetch(SiteInfoBean bean) throws IOException IxR:a(  
{ LnX^*;P5t  
siteInfoBean = bean; -;z\BW5y  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); dUSuhT  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 5L#M
7E  
if(tmpFile.exists ()) x#j_}L!V;  
{ S3cQC`^  
bFirst = false; M!'tD!NWc  
read_nPos(); pl&GFf o  
} -H]O&u3'c  
else M -TK  
{ ;\.&F
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nStartPos = new long[bean.getNSplitter()]; TA7w:<  
nEndPos = new long[bean.getNSplitter()]; A79SAheX#  
} -E"o)1Pj6C  
c[q3O**  
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R8*4E0\br  
} XW:(FzF  
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public void run() 8/v_uEG  
{ VZR6oia  
//获得文件长度 4R6 .G
O  
//分割文件 2c]O Mtk  
//实例FileSplitterFetch j)Gr@F>  
//启动FileSplitterFetch线程 N@S;{uK  
//等待子线程返回 )\^OI:E  
try{ c7_b^7h1  
if(bFirst) :Fl:bRH+  
{ (fS4qz:&l  
nFileLength = getFileSize(); _`58G#z  
if(nFileLength == -1) tnntHQ&b  
{ St<\qC  
System.err.println("File Length is not known!"); 5Z{[.&x  
} Ycm1
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else if(nFileLength == -2) Dl6zl6q?  
{ 1|CO>)*D  
System.err.println("File is not access!"); je\UfEo%  
} YQJ_t@0C  
else []NAV  
{ s!Vtwp9  
for(int i=0;i<nStartPos.length;i++) V,}cDT>  
{ i
8F~$6C  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 1'U-n{fD  
} :+n7oOV  
for(int i=0;i<nEndPos.length-1;i++) .w&Z=
YM  
{ ?##GY;#  
nEndPos = nStartPos[i+1]; ^m\n[<x^  
} -v] 0@jNe  
nEndPos[nEndPos.length-1] = nFileLength; 8~7EWl  
} 'yqp  
} Lm/^ 8V+  
~ nIZg5  
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//启动子线程 '1aOdEZA*  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length];
0vEa]ljS  
for(int i=0;i<nStartPos.length;i++) ;x"B ):?\  
{ #'T@mA  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ~QXNOtVsN  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), l8Ox]%F  
nStartPos,nEndPos,i); p/:L;5F  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 6|9fcIh]B  
fileSplitterFetch.start(); dc*#?G6^  
} ;(A'XA4 6N  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 4e4$AB"  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); $!t!=  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", =Ur/v'm  
nEndPos = " + nFileLength); ~W4<M
:R  
// fileSplitterFetch[nPos.length-1].start(); q4E{?  
-z@}:N-uR  
<GC:aG  
//等待子线程结束 #cA}B L!3  
//int count = 0; 4Y
'qoM;  
//是否结束while循环 @: NrC76  
boolean breakWhile = false; aOOY_S E  
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while(!bStop) g.'4uqU  
{ #~Q0s)Ze  
write_nPos(); ~![R\gps  
Utility.sleep(500); f;*\y!|lg~  
breakWhile = true; /<5/gV 1Q  
#"jWPe,d  
z
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for(int i=0;i<nStartPos.length;i++) 3j2}n o8O  
{ 'RhMzPmY>  
if(!fileSplitterFetch.bDownOver) n*V^Qf  
{ 7@ZL(G  
breakWhile = false; _\"?:~rUN  
break; k0,~wn\#h  
} !Bd2$y.  
} /[mCK3_  
if(breakWhile) Q8O38
uZ  
break; ;2$^=:8  
ky*-_  
phTZUmi  
//count++; nt4>9;  
//if(count>4) +IU]=qS  
// siteStop(); (mycUU%  
} RNPqW,B!0  
R8axdV9(  
q\ ?6-?Mr  
System.err.println("文件下载结束！"); GXwV>)!x  
} "C>KKs }  
catch(Exception e){e.printStackTrace ();} =|6IyL_N  
} 2'++G[z  
-y~JNDS1]  
xv /w %  
//获得文件长度 TJCoID7a8  
public long getFileSize() -7lJ   
{ dJ$}]   
int nFileLength = -1; lA{Sr0fTP  
try{ Tf+B<B:  
URL url = new URL(siteInfoBean.getSSiteURL());
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 5dhRuc  
httpConnection.setRequestProperty("User-Agent","NetFox"); F3?v&  
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:Y"f.>  
int responseCode=httpConnection.getResponseCode(); 4ed( DSN  
if(responseCode>=400) qsJo)SA  
{ \2T@]!n  
processErrorCode(responseCode); @wB$qd;v  
return -2; //-2 represent access is error %Dya-  
} K }r%OOn0  
Ek84yme#  
W}KtB1J  
String sHeader; .n"aQ
@!  
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G.9?ApG9  
for(int i=1;;i++) @]~\H-8  
{ "#JRw  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); #T+%$q [:  
//Utility.log(in.readLine()); iNha<iS+  
sHeader=httpConnection.getHeaderFieldKey(i); <^M`U>
 
if(sHeader!=null) 1Azigd0%  
{ l(
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if(sHeader.equals("Content-Length")) h!$W^Tm2g  
{ )wAqaG_d  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); x3]es"4Q  
break; aRR*<dY  
} zK33.HY  
} #b:8-Lt:M  
else kz+P?mopm  
break; Hl]3F^{  
} op[5]tjL  
} KyDQ<Dq&  
catch(IOException e){e.printStackTrace ();} =6/0=a[  
catch(Exception e){e.printStackTrace ();} r..\(r  
7j5l?K-  
N[czraFBD}  
Utility.log(nFileLength); c8#A^q}  
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return nFileLength; ;A1pqHr  
} Ig]Gg/1G  
qbmy~\ZY  
t(^c]*r~  
//保存下载信息（文件指针位置） S.BM/M  
private void write_nPos() 1S<V,9(  
{ fH>]>2fS  
try{ jg#%h`  
output = new DataOutputStream(new FileOutputStream(tmpFile)); lQldW|S>  
output.writeInt(nStartPos.length); oC"c%e8  
for(int i=0;i<nStartPos.length;i++) *l^h;RSx  
{ <$_B J2Z  
// output.writeLong(nPos); ]7Tjt A.\q  
output.writeLong(fileSplitterFetch.nStartPos); +:;r} 7Zh  
output.writeLong(fileSplitterFetch.nEndPos); _a^%V9t  
} y$7<ZBG
 
output.close(); 9)'L,Xt4:T  
} m8fxDepFA  
catch(IOException e){e.printStackTrace ();} UV$v:>K#  
catch(Exception e){e.printStackTrace ();} 0d~>zKho  
} 5nQ*%u\$Z  
@MS;qoc  
V`=#j[gX)=  
//读取保存的下载信息（文件指针位置） h]&8hl_'m  
private void read_nPos() xn}sh[<:P  
{ Av]<[ F/  
try{ k~h'`(  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); u-=%gx"Di  
int nCount = input.readInt(); O:WFh;c  
nStartPos = new long[nCount]; ,vl][MhM  
nEndPos = new long[nCount]; \XD&0inv  
for(int i=0;i<nStartPos.length;i++) Ag^Cb'3X  
{ z`]'~  
nStartPos = input.readLong(); `XS6t)!ik  
nEndPos = input.readLong(); tUH#%  
} ~Qeyh^wo  
input.close(); kTt;3Ia  
} ~bhesWk8!  
catch(IOException e){e.printStackTrace ();} XTyJ*`>  
catch(Exception e){e.printStackTrace ();} }hv>LL  
} 22)2o
lU  
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private void processErrorCode(int nErrorCode) d#T~xGqz  
{ KpA i
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System.err.println("Error Code : " + nErrorCode); 7g[T#B'/x,  
} F_$eu-y  
MPhO#;v  
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//停止文件下载 q;1]M[&  
public void siteStop() y".uu+hL`  
{ l 2y_Nz-;  
bStop = true; Zqc+PO3lw  
for(int i=0;i<nStartPos.length;i++) T}jryN;J
5  
fileSplitterFetch.splitterStop(); a`|&rggN  
|9$K'+'  
t 5g@t0$  
} wK!4:]rhG  
} uW},I6g  
//负责部分文件的抓取 Y1vl,Yi  
**FileSplitterFetch.java Ox#%Dm2  
*/ ^&>(_I\w.6  
package NetFox; UEbRg =6  
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import java.io.*; 7g^=   
import java.net.*; ,Y6Me+5B  
sg RY`U.C  
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public class FileSplitterFetch extends Thread { I4.^I/c(  
5B)Z@-x2  
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String sURL; //File URL c&vY0/ [  
long nStartPos; //File Snippet Start Position ,#@B3~giC  
long nEndPos; //File Snippet End Position sS7r)HV&GI  
int nThreadID; //Thread's ID VC,wQb1J/  
boolean bDownOver = false; //Downing is over nSdta'6  
boolean bStop = false; //Stop identical I'%vN^e^  
FileAccessI fileAccessI = null; //File Access interface qc;9{$?xV  
tQ=M=BPZ  
t&MJSFkiA  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException jr29+>  
{ /"Ws3.p  
this.sURL = sURL; #Y6'Q8gf  
this.nStartPos = nStart; #0V$KC*>  
this.nEndPos = nEnd; q|xJ)[AO  
nThreadID = id; A6v<+`?  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 o[pv.:w  
} %Aq+t&-BCX  
{PZNJ 2~  
{L^b['h@  
public void run() K"B2 SsC  
{ \q(DlqTqs  
while(nStartPos < nEndPos && !bStop) H}5zKv.T  
{ k\rzvo=U  
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try{ pVbgjJI  
URL url = new URL(sURL); W=fs"
<  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); xO"fg9a  
httpConnection.setRequestProperty("User-Agent","NetFox"); gIa/sD2m>  
String sProperty = "bytes="+nStartPos+"-"; ?$T!=e"  
httpConnection.setRequestProperty("RANGE",sProperty); s=9gp$9m  
Utility.log(sProperty); -F\xZ  
`&]<_Jc1  
'S]7:/CI  
InputStream input = httpConnection.getInputStream(); mv
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//logResponseHead(httpConnection); ,*ZdMw!  
#
/!fLU@  
<J" 7ufHSQ  
byte[] b = new byte[1024]; XG2&_u&  
int nRead; frV*
+  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ^|-*amh  
{ X=$WsfN.h  
nStartPos += fileAccessI.write(b,0,nRead); UZ#Yd|'PD  
//if(nThreadID == 1) 0*0]RC5?  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); *;b.x"  
} )* 5R/oy,  
g#b[-)Qx  
r:Uqtqxh  
Utility.log("Thread " + nThreadID + " is over!"); #'m&<g,  
bDownOver = true; m:U.ao6  
//nPos = fileAccessI.write (b,0,nRead); :KY920/,  
} )*<=:  
catch(Exception e){e.printStackTrace ();} $h"Ht2/ J  
} 1|/P[!u  
} W3K&C[f  
qOOF]L9r%u  
{hYH4a&Hb  
//打印回应的头信息 4pNIsjl}  
public void logResponseHead(HttpURLConnection con) 1UG5Q-  
{ (3PkTQlE  
for(int i=1;;i++) -XNjyXm2  
{ {KkP"j'7h  
String header=con.getHeaderFieldKey(i); V}<Hx3!  
if(header!=null) P>q"P1&{  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); "";[U  
Utility.log(header+" : "+con.getHeaderField(header)); W+N9~.q\^  
else #lDf8G|ST~  
break; Z+%Uwj  
} 4wfT8CL  
} /'vCO |?L  
uFxhr2 <z  
: V16bRpjL  
public void splitterStop() zzm
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{ VK)1/b=yT  
bStop = true; sbnNk(XINQ  
} l-|hvv5g  
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} ND);7  
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':al4m"  
/* kT|{5Kn&s  
**FileAccess.java zdY+?s)p  
*//文件访问(定位，写) 0a<:.}  
package NetFox; ?1%/G<  
import java.io.*; 8z,i/:  
:5 XNV6^|  
dMkDNaH,  
public class FileAccessI implements Serializable{ MZ" yjQA  
%N}OMc.W  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 yVds2J'w-  
RandomAccessFile oSavedFile; QUa_gYp0v  
long nPos; g-B~"tp  
`>M;f%s  
c6zghP3dR  
public FileAccessI() throws IOException v.Fq.  
{ b'i-/l$  
this("",0); B<)c{kj  
} oy+``W~  
A4!IbJD,0  
nsO!  
public FileAccessI(String sName,long nPos) throws IOException ~3p :jEM.[  
{ r8PXdNg  
oSavedFile = new RandomAccessFile(sName,"rw"); ;uw`6 KJ  
this.nPos = nPos; wk @-O}W  
oSavedFile.seek(nPos); ~~J xw ]  
} &+t! LM  
w.s-T.5.j  
MDETAd  
public synchronized int write(byte[] b,int nStart,int nLen) \
)
H}  
{ NpS*]vSO  
int n = -1; V?KACYd@O  
try{ t{)Z$)
'  
oSavedFile.write(b,nStart,nLen); 9rhIDA(wc  
n = nLen; N^,@s"g  
} kz4d"bTb  
catch(IOException e) Be?b| G!M  
{ {P'TtlEp  
e.printStackTrace (); tnx
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} 'k|?M  
v9Kx`{1L  
'2`MT-  
return n; Y6LoPJ  
} Bvbv~7g(  
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n,KOQI;  
} bj6-0`  
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/* #ma#oWqF}  
**SiteInfoBean.java +h!OdWD9
 
*/ jVh I`F{n  
package NetFox; Obl']Hr{y9  
V0'T)  
*Q=3v  
public class SiteInfoBean { iTb k]$  
:\ %.x3T'  
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private String sSiteURL; //Site's URL \U^0E> d  
private String sFilePath; //Saved File's Path :H}a/ x*ur  
private String sFileName; //Saved File's Name D9OI",h  
private int nSplitter; //Count of Splited Downloading File "wk~[>  
u_0&`zq  
&[]0yNG  
public SiteInfoBean() Fi8'3/q-^  
{//nSplitter的缺省值为5 `Qzga}`"]  
//default value of nSplitter is 5 [Xy^M3
  
this("","","",5); Vf Jpiv1  
} -8-BVU  
Vwj^h
 
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) YHoj^=/b  
{ EH;w <LvT  
sSiteURL= sURL; L,I5/K6  
sFilePath = sPath; -C9_gZ  
sFileName = sName; a-I3#3VJ@  
this.nSplitter = nSpiltter; Vq)6+n8o  
{?-@`FR-  
.SdHFWx  
} U p1&(
 
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f< A@D"m/  
public String getSSiteURL() A0x"Etbw)  
{ |T53m;D  
return sSiteURL; 3U#z {%  
} \/8 I6a=  
]6wo]nV[P  
eQBR*@x  
public void setSSiteURL(String value) I+ZK \?Rs  
{ =ytB\e  
sSiteURL = value; '\[o>n2  
} kNX"Vo]1  
X2 {n&K  
7%aaqQ1T  
public String getSFilePath() #q2cVN1  
{ ]ZkhQ%  
return sFilePath; j~
+<~2%c  
} 4z~ fn9g  
INQ0h`T  
>
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public void setSFilePath(String value) _c}@Fi+E  
{ R-Y|;  
sFilePath = value; *&VH!K#@{  
} ZVo%ssVt  
chjXsq#Q^  
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public String getSFileName() &Nx'Nq
9y  
{ P19nF[A  
return sFileName; E|u#W3-:  
} S"FIQ&n  
$t' .  
&V;^xMO!  
public void setSFileName(String value) 8nOMyNpy~M  
{ N 3IF j  
sFileName = value; |%JJ S^)  
} 5@3[t`n'  
>h3r\r\n3  
+dWx?$n  
public int getNSplitter() K\5'pp1  
{ S4RvWTtQV  
return nSplitter; m&)5QX  
} L(tA~Z"k  
!;'.mMO&%  
r&AX  
public void setNSplitter(int nCount) =
2HR+  
{ & [)1LRt_  
nSplitter = nCount; M{Ss?G4H  
} J8|F8dcz  
} 2UYtFWB9o  
F,0@z/8a  
>sAZT:&gv  
/* %-? :'F!1  
**Utility.java (17%/80-J  
*/ / d S!  
package NetFox; G{*m] 0Q  
bH}6N>Fp  
+^% y&8e  
public class Utility { FC.d]XA%/d  
` aTkIo:ms  
YxH"*)N  
public Utility() Kp") %p#  
{ >Lo 0,b$  
8>.l4:`  
jg8j>"Vj>  
} 0RY{y n3  
JZ6{W  
//线程睡眠 41luFtE9  
public static void sleep(int nSecond) @DgJxY|  
{ (fON\)l  
try{ [;M31b3  
Thread.sleep(nSecond); [u[`!L=  
} f$a%&X6"-  
catch(Exception e) 2`(-l{3  
{ q1j<p
)(  
e.printStackTrace ();  /1-  
} jbQ2G|:Q  
} %MyA;{-F6  
@MIBW)P<  
//日志 jRN*W2]V  
public static void log(String sMsg) 0raVC=[  
{ UkrqHHpy  
System.err.println(sMsg); ]_NN,m>z  
} "oZ]/(  
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55xv+|k  
public static void log(int sMsg) 4`@]jm  
{ 82Fq}N <  
System.err.println(sMsg); K @3 yS8F  
} 1aKYxjYM  
} ]@OGp:Hz  
0'!v
-`.  
m#SDB6l  
/* hQ&S*f&='  
**TestMethod.java Dt,b\6  
*/ & f7{3BK  
package NetFox; [.DSY[!8U  
?29zcuRaru  
@xR7>-$0p  
public class TestMethod { )e.Y"5My  
6zK8-V?9F  
*OU>s;"$  
public TestMethod() Xv3u}nPMq  
{ ///xx/weblogic60b2_win.exe IuDg-M[  
try{ <1[WNj2[  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); -o\$.Q3  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); %zE_Q  
SiteFileFetch fileFetch = new SiteFileFetch(bean); lcgT9m#  
fileFetch.start(); c;_GZ}8  
} :+ksmyW  
catch(Exception e){e.printStackTrace ();} Tj@}O:q7:  
GF5WR e(E  
!=C4=xv  
} dw,Nlf~*0  
2SU G/-P#  
Q\G8R^9j p  
public static void main(String[] args) Izq]nR  
{ BQ
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new TestMethod();
!}wJ+R ^2  
} 0S@O]k)  
} d;&'uiS  
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