http断点续传简单实现（java)

/*  o@_pV  
**SiteFileFetch.java qFmvc  
*/ FqiCzP4  
package NetFox; w}<BO> z  
import java.io.*; \LRno3  
import java.net.*; A>^\jIB>  
i% k`/X;  
3|%Q{U  
public class SiteFileFetch extends Thread { tv)x(MX  
v\:>} <gc  
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SiteInfoBean siteInfoBean = null; //文件信息Bean :L`  
long[] nStartPos; //开始位置 Zi/l.=9n  
long[] nEndPos; //结束位置 0@1AH<  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 q@P
5c  
long nFileLength; //文件长度 wo84V!"A  
boolean bFirst = true; //是否第一次取文件 bT>% *  
boolean bStop = false; //停止标志 Wx~0_P  
File tmpFile; //文件下载的临时信息 uk_?2?>-5  
DataOutputStream output; //输出到文件的输出流 0X#tt`;  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） "8VCX
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public SiteFileFetch(SiteInfoBean bean) throws IOException gOa'o<  
{ ?3Wh.%n  
siteInfoBean = bean; -yOrNir}W  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); .hlr)gF&
)  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); VB*$lxX  
if(tmpFile.exists ()) zl46E~"]x  
{ y[S5  
bFirst = false; UDV,co  
read_nPos(); nCEt*~t9VE  
} NFPW#-TF  
else @
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{ I(/W+o  
nStartPos = new long[bean.getNSplitter()]; B[ooT3V  
nEndPos = new long[bean.getNSplitter()]; R>[2}R30  
} o87. (  
o`\l&jUNe  
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} "ji4xy  
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public void run() W'rft@J$  
{ wH~Q4)#=o  
//获得文件长度 ]q7
\  
//分割文件 aDR<5_Yb  
//实例FileSplitterFetch k&ujr:)5Y5  
//启动FileSplitterFetch线程 ( }5k"9Z  
//等待子线程返回 _Qs)~  
try{ /s uz>o\  
if(bFirst) Fkj\U^G  
{ +wwpaR`  
nFileLength = getFileSize(); J`;G9'n2  
if(nFileLength == -1) ,ju1:`  
{ L{Epkay,{  
System.err.println("File Length is not known!"); :51Q~5
k4  
} P~iu|j  
else if(nFileLength == -2) cysYjuI i  
{ F4>}mIA  
System.err.println("File is not access!"); ItHKpTer  
} Lo @mQ  
else 0@{K'm/  
{ X !NH?0)  
for(int i=0;i<nStartPos.length;i++) ;2kiEATQ 1  
{ UL$^zR3%d  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); "lx}.  
} o\1"ux;b  
for(int i=0;i<nEndPos.length-1;i++) `Z>4}<~+  
{ :}FMauHh  
nEndPos = nStartPos[i+1]; $jo}?Y+  
} Y(78qs1w  
nEndPos[nEndPos.length-1] = nFileLength; 37x2fnC  
} d"uR1rTk  
} FVT_%"%C9  
]plg@  
T/MbEqAf  
//启动子线程 ,sP7/S)FR  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; e(x1w&8dB  
for(int i=0;i<nStartPos.length;i++) ["Ep.7=SU  
{ GKH7Xx(  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), F
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Erl
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nStartPos,nEndPos,i);  nsij
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Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); i*..]!7e  
fileSplitterFetch.start(); z<ptrH  
} 0wB ?U~  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), nBjfR2TuF  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ,*?bET $  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", lLxKC7b  
nEndPos = " + nFileLength); cgc|G  
// fileSplitterFetch[nPos.length-1].start(); o~<37J3).  
0XSZ3dY&+  
;n00kel$  
//等待子线程结束 EN` --^  
//int count = 0; QL"fC;xUn,  
//是否结束while循环 ?Q="w5OOD  
boolean breakWhile = false; 8<Asg2]6  
-uqJ~gD  
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while(!bStop) [IF3,C  
{ ;gTdiwfgZ=  
write_nPos(); <tMiI)0%  
Utility.sleep(500); sKB])mf]  
breakWhile = true; |L.QIr,jCC  

>1T=Aw2Z.  
C]K@SN$   
for(int i=0;i<nStartPos.length;i++) 2TmQaDu%b  
{ )}9Ef"v|  
if(!fileSplitterFetch.bDownOver) ^, q\S  
{ L9Z:>i?  
breakWhile = false; L qMH]W  
break; ]MfT5#(6h  
} LtJ$ZE^GB  
} G?&0Z++  
if(breakWhile) jAfUz7@  
break; tmDI2Z%7  
NjMbQM4  
}=?kf3k  
//count++; 5Lo{\7%  
//if(count>4) )/HSt%>  
// siteStop(); &`0y<0z  
} Z 3m5DK  
`XB(d@%  
*eH[~4  
System.err.println("文件下载结束！"); -i:Zi}f  
} {kD|8["Ie'  
catch(Exception e){e.printStackTrace ();} R}8!~Ma`|  
} `LVItP(GUM  
&Zs h-|N  
{vx{H
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//获得文件长度 CSRcTxH  
public long getFileSize() z,87;4-  
{ }N#jA yp!  
int nFileLength = -1; uwsGtgd&  
try{ Z`o}xV  
URL url = new URL(siteInfoBean.getSSiteURL()); [~`; .7~  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); A 7'dD$9  
httpConnection.setRequestProperty("User-Agent","NetFox"); J)oa:Q  
7C9qkQ Jqn  
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int responseCode=httpConnection.getResponseCode(); O`g44LW2n  
if(responseCode>=400) xqmP/1=NO
 
{ Xnt`7L<L  
processErrorCode(responseCode); zq80}5%2CT  
return -2; //-2 represent access is error 2BS2$#c>  
} S)C =Q~&  
T12?'JL^r  
:[#HP66[O5  
String sHeader; r4@!QR<h  
f7)}A/$4+  
"S(m1L?  
for(int i=1;;i++) &"BmCDOq  
{ ?=dyU(  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); v:PNt#Ta  
//Utility.log(in.readLine()); ELk$lm&@  
sHeader=httpConnection.getHeaderFieldKey(i); {oy(08`6  
if(sHeader!=null) yyPkjUy[  
{ q@~N?$>  
if(sHeader.equals("Content-Length")) -A(]",*J  
{ 1 9$ufod  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); y)t< r  
break; *^bqpW2$q  
} R;.zS^LL  
} sEt5!&  
else kpsus \T  
break; @OZW1
p  
} cR[)[9}  
} W
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catch(IOException e){e.printStackTrace ();} Sir7TQ4B  
catch(Exception e){e.printStackTrace ();} .M!6${N);  
)7<JGzBZ1  
tbJB0T|G  
Utility.log(nFileLength); -PbGNF  
afqLTWUS  
1y$Bz?4  
return nFileLength; 0t*JP
 
} bLUn>ch  
pFXDo4eH  
\om$%FUP  
//保存下载信息（文件指针位置） AFGWlC#`  
private void write_nPos() S)Sv4Qm  
{ )}\jbh>RH  
try{ ;hA>?o_i(  
output = new DataOutputStream(new FileOutputStream(tmpFile)); yw41/jHF  
output.writeInt(nStartPos.length); R9f*&lj  
for(int i=0;i<nStartPos.length;i++) - U!:.  
{ NC)Iu  
// output.writeLong(nPos); TFb9gOTJ  
output.writeLong(fileSplitterFetch.nStartPos); +yiGZV/X  
output.writeLong(fileSplitterFetch.nEndPos); ~=aD*v<3d  
} 'IY?7+[  
output.close(); <_=a1x  
} P#\L6EO.  
catch(IOException e){e.printStackTrace ();} d^ L`do
t  
catch(Exception e){e.printStackTrace ();} r"x|]nvg^  
} }o0R`15dA  
i64a]=  
"1$OPt5  
//读取保存的下载信息（文件指针位置） {(U?)4@  
private void read_nPos() 8`Q8Mct$<  
{ q]T{g*lT  
try{ }i!hzkK#  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); F&<si:}KB  
int nCount = input.readInt(); /B.\6  
nStartPos = new long[nCount]; ):; &~  
nEndPos = new long[nCount]; 8G; t[9  
for(int i=0;i<nStartPos.length;i++) ?DzKqsS'  
{ x* *]@v"g  
nStartPos = input.readLong(); S75wtz)e  
nEndPos = input.readLong(); hn{]Q@(I  
} >0~|iRySi  
input.close(); r&@#,g  
} \< <u  
catch(IOException e){e.printStackTrace ();} Bwj^9J/ob  
catch(Exception e){e.printStackTrace ();} RJYuyB  
} fdc ?`4  
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private void processErrorCode(int nErrorCode) |'9%vtbM  
{ "toyfZq@  
System.err.println("Error Code : " + nErrorCode); Q#Q]xJH  
} N`1:U 4}  
>p [|U`>{  
58\Rl  
//停止文件下载 bq/m?;  
public void siteStop() {P"$;_Y"<  
{ S;sggeP7,  
bStop = true; B!0o6)u'  
for(int i=0;i<nStartPos.length;i++) >&6pBtC_  
fileSplitterFetch.splitterStop(); [tGAo/  
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c"Kl@[1\~  
} /{vv n  
} _W'>?e0i  
//负责部分文件的抓取 s%z\szd*  
**FileSplitterFetch.java A&*l
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*/ ()e.J  
package NetFox; +dq&9N/  
ivYHq#b59  
hNgbHzW  
import java.io.*; 6My=GByC  
import java.net.*; xy)Y)yp  
!#j y=A  
43-mv1>.  
public class FileSplitterFetch extends Thread { 2a8ZU{wjn  
vh5`R/<3  
4+e9:r]  
String sURL; //File URL ~XQj0'  
long nStartPos; //File Snippet Start Position f4YcZyBGv  
long nEndPos; //File Snippet End Position ^BIB'/Kh)  
int nThreadID; //Thread's ID F$<>JEdX  
boolean bDownOver = false; //Downing is over Nd'+s>d0
 
boolean bStop = false; //Stop identical ! 7A _UA8  
FileAccessI fileAccessI = null; //File Access interface )#n0~7 &  
E/2kX3}  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException F^.w:ad9<  
{ @{*z1{  
this.sURL = sURL; /tR@J8pV  
this.nStartPos = nStart; "| cNY_$&s  
this.nEndPos = nEnd; ,e$]jC<sv2  
nThreadID = id; FDBj<uXfM|  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ts%XjCN[  
} c]LE9<G  
<wWZ]P2]  
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public void run() nt.A X  
{ Q%)da)0:c  
while(nStartPos < nEndPos && !bStop) 0NrUB  
{ .RFijr  
vVB8zS~l ,  
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try{ Y'7f"W  
URL url = new URL(sURL); JAJo^}}{b  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); "#1KO1@G  
httpConnection.setRequestProperty("User-Agent","NetFox"); V'?bZcRr~  
String sProperty = "bytes="+nStartPos+"-"; |s[kY  
httpConnection.setRequestProperty("RANGE",sProperty); 2yZ/'}Mw  
Utility.log(sProperty); h&@A'om~  
LA &W@  
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InputStream input = httpConnection.getInputStream(); )7!q>^S{B  
//logResponseHead(httpConnection); VqGmZ|+8  
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byte[] b = new byte[1024]; ]."
~)  
int nRead; qd$Y"~Mco  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) eGcc'LBr;  
{ F]o&m::/K  
nStartPos += fileAccessI.write(b,0,nRead); K8`Jl=}z%&  
//if(nThreadID == 1) [ u7p:?WDW  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); !SRElb A;i  
} )y>o;^5
'  
qQK0s*^W  
A+Uil\%  
Utility.log("Thread " + nThreadID + " is over!"); *nJy  
bDownOver = true; 6[3oOO:uo  
//nPos = fileAccessI.write (b,0,nRead); \yt-_W=
[  
} 1./uJB/  
catch(Exception e){e.printStackTrace ();} (ndXz  
} p1~u5BE7O  
} 2kMBe%  
|dNJx<-  
FvpaU\D  
//打印回应的头信息 <ua`WRQr  
public void logResponseHead(HttpURLConnection con) dJyf.VJ  
{ X*f#S:kiNU  
for(int i=1;;i++) C>l{_J)n  
{ 6&,n\EXF  
String header=con.getHeaderFieldKey(i); me-Tv7WL  
if(header!=null) .Ukejx  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); |e{F;8  
Utility.log(header+" : "+con.getHeaderField(header));  l Ozi|  
else zgre&BV0q  
break; obA}SF  
} n-ZOe]3  
} bu[PQsT  
0zJT_H+  
0X \OQ;  
public void splitterStop() : L}Fm2^  
{ `|nCr  
bStop = true; f3_-{<FZ  
} [I6(;lq2  
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} ^G:}%4  
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q  
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/* M"XILNV-~  
**FileAccess.java DJ&ni`  
*//文件访问(定位，写) 9Q\CJ9  
package NetFox; 4wLN#dpeEy  
import java.io.*; iYbp^iVg  
[/Q .MmnL  
$y%X#:eLJ  
public class FileAccessI implements Serializable{ }5_[t9LX  

:mP%qG9U  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 }~B@Z\`O  
RandomAccessFile oSavedFile; h?t#ABsVK  
long nPos; ~nQ=iB  
]0[Gc \h}  
7kiZFHV  
public FileAccessI() throws IOException Ih Yso7g  
{ +Cs[
]~  
this("",0); u.\FNa  
} ;4(ULJ*  
U`)\|\NY  
C:r@)Mhq  
public FileAccessI(String sName,long nPos) throws IOException ?+3vK=Rf}  
{ hY*ylzr83  
oSavedFile = new RandomAccessFile(sName,"rw"); qKt*<KGeY  
this.nPos = nPos; *??!~RE  
oSavedFile.seek(nPos); 1co;U  
} R7'6#2y  
a7$]" T 7  
JAt$WW{  
public synchronized int write(byte[] b,int nStart,int nLen) 6YErF|  
{ [N@t/^gRC  
int n = -1; " a&|{bv  
try{ RSv?imi=  
oSavedFile.write(b,nStart,nLen); u92);1R  
n = nLen; IKz3IR eu  
} :Xe,=M(l~  
catch(IOException e) \,n|V3#G  
{ T[?wbYfW  
e.printStackTrace (); Uz4!O  
} ;`")3~M3*  
u& 4i=K'x8  
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return n; ;+-@AYl  
} Fx@ovI- 5  
g?7I7W~?`  
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} Xu.Wdl/{Ra  
7lLh4__;`6  
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/* <w,NMu"  
**SiteInfoBean.java dnwTD\),  
*/ Etj0k} A  
package NetFox; @Sr{6g
*I  
{th=MldJ?  
pA%}CmrMq  
public class SiteInfoBean { Q1 t-Z;X  
@p$Nw.{'  
61aU~w11a  
private String sSiteURL; //Site's URL l1M %   
private String sFilePath; //Saved File's Path AfAlDM'  
private String sFileName; //Saved File's Name h0cdRi  
private int nSplitter; //Count of Splited Downloading File LL0Y$pHV  
K'6NW:zp~  
'3i,^g0?t0  
public SiteInfoBean() ]2_
b_ok  
{//nSplitter的缺省值为5
_ww>u""B~  
//default value of nSplitter is 5 m}-*B1  
this("","","",5); ~M c'~:{O  
} ]NEr]sc-"F  
cD%_+@GaU  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 0I v(ioB=  
{ `i
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sSiteURL= sURL; +UM%6Z=+  
sFilePath = sPath; $q|-9B  
sFileName = sName; t6,bA1*5y  
this.nSplitter = nSpiltter; 8mm]>u$  
wB(X(nr  
!&eKq?P{j  
} 7Mj:bm&9  
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public String getSSiteURL() {`ghX%M(l  
{ YAdk3y~pL  
return sSiteURL; /g`!Zn8a  
} &FpoMW  
/Kd9UQU  
b)[2t^zG  
public void setSSiteURL(String value) mG*ER^Y@D  
{ ez-jVi-Fi  
sSiteURL = value; s+-V^{Ht  
} {i^F4A@=Z  
$eq*@5B  
o#Viz:  
public String getSFilePath() #FhgKwx  
{ PY@BgL=/  
return sFilePath; Dq~\U&U\$  
} '% if< /  
/prR;'ks  
~Fe$/*v  
public void setSFilePath(String value) <-h[
I&."  
{ {y%|Io`P  
sFilePath = value; '>^!a!<G  
} J*Q+$Ai~  
%Q080Ltet  
 ?8/T#ox  
public String getSFileName() *UZd!a)  
{ !{+a2wi  
return sFileName; 1\X_B`xwD  
} dJ9v/k_  
Y6[O s1  
m S4N%Q  
public void setSFileName(String value) 'Ul^V  
{ lD#S:HX  
sFileName = value; g7;O
Z#\  
} X
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tuslkOE#  
public int getNSplitter() }rQ0*h  
{ d6XdN  
return nSplitter; j0~dJ#  
} )tv~N7  
=.]{OT  
 <dKHZ4  
public void setNSplitter(int nCount) -y'tz,En.  
{ w+Y_TJ%  
nSplitter = nCount; '!"rE1e  
} 2w;Cw~<=d  
} H1d2WNr[  
*AG01# ZF  
[85b+SKW  
/* C({r1l4[D  
**Utility.java hEA;5-m  
*/ .3CQFbHF  
package NetFox; `$Y%c1;  
<64#J9T^  
_&RGhA  
public class Utility { fP/;t61Z  
w&>*4=^a  
#OwxxUeZ  
public Utility() wCEcMVT  
{ "#.L\p{Zy  
f%/6kz  
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} #('GGzL6c  
\HL66%b[  
//线程睡眠 RN2z/FUf  
public static void sleep(int nSecond) %F87
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{ %x8vvcO^t  
try{ |,T"_R_K  
Thread.sleep(nSecond); XG!^[ZDs  
} .umN>/o[  
catch(Exception e) XzB3Xs?W2
 
{ ]zz%gZz  
e.printStackTrace (); _LFABG=  
} i8!err._  
} XZ"oOE0=  
TMD*-wYr  
//日志 uBw[|,yn2*  
public static void log(String sMsg) c27Zh=;Tj  
{ F8&L'@m9>  
System.err.println(sMsg); @o6!  
} i(YR-vYK  
Ch)E:Dvq6  
"8 ?6;!,  
public static void log(int sMsg) 3$3
%W<&^  
{ XCT3:db  
System.err.println(sMsg); %3yrX>Js
 
} ~xJ^YkyH  
} b
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/* ddY-F }z~  
**TestMethod.java $S^rKp#  
*/ LhSXz>AX  
package NetFox; R@KWiV  
w{riXOjS4  
k- exqM2x=  
public class TestMethod { t$PJ*F67M  
(ZP e{;L.  
1U(!%},  
public TestMethod() p.5 *`, )  
{ ///xx/weblogic60b2_win.exe _6->D[dB  
try{ ]}pAZd  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); :BF WX  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); _TyQC1 d  
SiteFileFetch fileFetch = new SiteFileFetch(bean); iV:\,<8d  
fileFetch.start(); AD>/#Ul  
} 9hgIQl  
catch(Exception e){e.printStackTrace ();} 1[-RIN;U8  
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gX(8V*os^  
} x[R?hS,0t  
X;v{,P=J  
<
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public static void main(String[] args) X7SSTcA  
{ 88}04  
new TestMethod(); 2
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} mhF@S@  
} _)~|Z~  
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