http断点续传简单实现（java)

/* XQ|j5]  
**SiteFileFetch.java 01SFOPuR%(  
*/ T_;G))q'  
package NetFox; DrV
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import java.io.*; .Q6{$Y%l  
import java.net.*; y(p:)Iv  
"b+3 &i|  
ud~VQXZo  
public class SiteFileFetch extends Thread { BYA=M*f  
;R- z3C  
A~~|X  
SiteInfoBean siteInfoBean = null; //文件信息Bean brhJ&|QDE  
long[] nStartPos; //开始位置 HDfQ9__  
long[] nEndPos; //结束位置 ">4[+'  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 kH
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long nFileLength; //文件长度 94>7-d  
boolean bFirst = true; //是否第一次取文件 ^Qb!k/$3y  
boolean bStop = false; //停止标志 *rMN,B@  
File tmpFile; //文件下载的临时信息 <?`e9o  
DataOutputStream output; //输出到文件的输出流 qo&SJDG  
h19.b:JT  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ",,qFM!  
public SiteFileFetch(SiteInfoBean bean) throws IOException B#/~U`t*  
{ &hM,b!R|  
siteInfoBean = bean; -QHzf&D?  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); f"}14V  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); d'eM(4R@  
if(tmpFile.exists ()) ,:Y=,[n  
{ =S?-=jPtg  
bFirst = false; u BW  
read_nPos(); Ml_:Q]kl^  
} P^{`d_[K%  
else ?2bE=|  
{ ]a@v)aa-  
nStartPos = new long[bean.getNSplitter()]; ]MH \3g;  
nEndPos = new long[bean.getNSplitter()]; 3T#3<gqM[  
} C(Bar#  
@5nkI$>3z  
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} fqp7a1qQl  
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&  
public void run() h"%,eW|^  
{ (Gb{ckzs  
//获得文件长度 XajY'+DIsz  
//分割文件 Jv$2wH  
//实例FileSplitterFetch Sv]"Y/N  
//启动FileSplitterFetch线程 Z(clw  
//等待子线程返回 &G5I0:a   
try{ @eD~FNf-]  
if(bFirst) oFx gR9  
{ f\%X7.  
nFileLength = getFileSize(); xVmUmftD  
if(nFileLength == -1) u*YuU%H=  
{ L bK1CGyA  
System.err.println("File Length is not known!"); K {N;k-  
} hQRc,d6x5  
else if(nFileLength == -2) r?{LQWP>e  
{ qb/!;U_  
System.err.println("File is not access!"); Y&:\s8C  
} }jy7,+  
else Iw-6Z+ 94  
{ %4g4 C#  
for(int i=0;i<nStartPos.length;i++) 4xC6#:8  
{ !P3tTL!*L  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); kJ:5msKwC  
} (TK cSVR  
for(int i=0;i<nEndPos.length-1;i++) UgBY ){<  
{ ,}xC) >  
nEndPos = nStartPos[i+1]; 5Szo5  
} Hrc
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nEndPos[nEndPos.length-1] = nFileLength; 'aSORVq^e[  
} oFA$X Y  
} X=7vUb,\gB  
fwGz00C/U  
Czl 8Q oH  
//启动子线程 "+OMo-<K7  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; d=Ihl30m  
for(int i=0;i<nStartPos.length;i++) PzG:M7  
{ @!tmUme1c  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 2/W0y!qh1  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), e&I.kC"j6  
nStartPos,nEndPos,i); R~u7
;Wv  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); D}=i tu  
fileSplitterFetch.start(); C]@B~X1H^  
} PDiorW}]k  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), T%b^|="@  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ]7ZC>.t  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 6v#sq  
nEndPos = " + nFileLength); s`#j8>`M  
// fileSplitterFetch[nPos.length-1].start(); uX!y,a/"  
HAOrwJFqU  
0R{R=r]  
//等待子线程结束 Z\yLzy#8  
//int count = 0; G5@@m-  
//是否结束while循环 5_T>HHR6  
boolean breakWhile = false; 2/NWWoKw  
#rL@  
W8/6  
while(!bStop) Y{B_OoTun  
{ CHSD8D  
write_nPos(); 'Z%aBCM  
Utility.sleep(500); = ft$j  
breakWhile = true; w4/)r-Z4I  
R3=E?us!  
Pg}G4L?H;J  
for(int i=0;i<nStartPos.length;i++) )bJ6{&  
{ 0md{e`'q:  
if(!fileSplitterFetch.bDownOver) `o-<,  
{ .jU0Hu{F4  
breakWhile = false; !,WRXE&j  
break; n_gB#L$  
} gI$`d?[0{  
} z?g4^0e  
if(breakWhile) ]nGA1S{  
break; "s^@PzQpN  
;^SgV   
3W00,f^9  
//count++; ijS
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//if(count>4) Vc<n6  
// siteStop(); <GlV!y  
} H`..)zL|  
,l"2MXD  
%6?}gc_  
System.err.println("文件下载结束！"); ;qQzF  
} e=$xn3)McY  
catch(Exception e){e.printStackTrace ();} *)sz]g|d  
} eesLTyD2_  
yr DYw T  
66;O3g'  
//获得文件长度 R9HS%O6b6  
public long getFileSize() e/%YruzS  
{ rx)Q]  
int nFileLength = -1; rkXSygb  
try{ X0L{#U  
URL url = new URL(siteInfoBean.getSSiteURL()); 
O  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); U5s]dUs (  
httpConnection.setRequestProperty("User-Agent","NetFox"); 'GT`%ck  
CawVC*b3  
X~b+LG/  
int responseCode=httpConnection.getResponseCode(); 8hV:bz"  
if(responseCode>=400) k!rz8S"  
{ tV%\Jk),  
processErrorCode(responseCode); k}7)pJNj  
return -2; //-2 represent access is error 'v5gg2  
} mSp7H!  
<T9m.:l  
G7xjW6^T  
String sHeader; k82LCV+6  
"6h.6_bTw  
#J9XcD{1  
for(int i=1;;i++) RGOwm~a  
{ uQ)]g  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); jl7-"V>j?;  
//Utility.log(in.readLine()); |]^! 4[!U  
sHeader=httpConnection.getHeaderFieldKey(i); WJ,ON-v  
if(sHeader!=null) =,9'O/br  
{ nQMN2jM  
if(sHeader.equals("Content-Length")) -I<`!kH*  
{ o?\Pw9Y  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); l^Z~^.{y  
break; oDK\v8w-  
} 7qp|Msf},  
} )f|6=x4  
else < ,n4|z)  
break; WVFy ZpB  
} 81C?U5  
} ]C^*C|  
catch(IOException e){e.printStackTrace ();} yIP IA%dJ  
catch(Exception e){e.printStackTrace ();} 6FAP *V;  
/zAx`H  
$80/ub:R  
Utility.log(nFileLength); Wb$bCR#?<  
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;#  
return nFileLength; B 8,{jwB  
} 4,8 =[  
\`&fr+x  
A
2 )%+  
//保存下载信息（文件指针位置） ~d]7 Cl  
private void write_nPos() jeNEC&J  
{ Ac%K+Pgk.
 
try{ vN
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output = new DataOutputStream(new FileOutputStream(tmpFile)); }2"k:-g  
output.writeInt(nStartPos.length); nIT=/{oyi  
for(int i=0;i<nStartPos.length;i++) *O2j<3CHf  
{ p5ihuV,  
// output.writeLong(nPos); |M&/(0  
output.writeLong(fileSplitterFetch.nStartPos); [sRQd;+  
output.writeLong(fileSplitterFetch.nEndPos); 6IH^rSUSK  
}  su$juI{  
output.close(); w0SgF/"@  
} z9ZAY!Zhq]  
catch(IOException e){e.printStackTrace ();} +g&W423k_  
catch(Exception e){e.printStackTrace ();} jHzb,&
  
} wq#3f#3V  
9 R1]2U$|  
^~$ o-IX  
//读取保存的下载信息（文件指针位置） L|Iq#QX|  
private void read_nPos() d)HK9T|B  
{ #(G&%I A|;  
try{ ^TGHWCK!t  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); lw{|~m5`  
int nCount = input.readInt(); c+c^F/  
nStartPos = new long[nCount]; Uyh#g^r  
nEndPos = new long[nCount]; fAi113q!  
for(int i=0;i<nStartPos.length;i++) d29HEu  
{ P^ V
NB  
nStartPos = input.readLong(); b6ddXM\Z  
nEndPos = input.readLong(); 9#7zjrB  
} h9mR+ng*oD  
input.close(); .N2Yxty8>  
} 7+bzCDKU  
catch(IOException e){e.printStackTrace ();} H?m2|.  
catch(Exception e){e.printStackTrace ();} 5;*C0m2%i  
} k-/$8C  
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y{<7OTA)  
private void processErrorCode(int nErrorCode) O1"!'Gk[!L  
{ ' wEP:}  
System.err.println("Error Code : " + nErrorCode); ]n_A~Yr  
} jEadVM9  
[0Sd +{Q  
eAj}/2y"  
//停止文件下载 D3OV.G]`  
public void siteStop() @\a- =  
{ X"]ZV]7(]s  
bStop = true; 'n=D$j]X  
for(int i=0;i<nStartPos.length;i++) }Z|a?J@CZm  
fileSplitterFetch.splitterStop(); slbV[xR  
~F-,Q_|-  
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}
%WR  
} %F7k| Na  
//负责部分文件的抓取 Yp8$0KK  
**FileSplitterFetch.java IM+PjYJ  
*/ ur|2FS7  
package NetFox; hI yfF  
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import java.io.*; /[p4. FL  
import java.net.*; ?w+T_EH  
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public class FileSplitterFetch extends Thread { sQkP@Y  
!Kis,e  
DbDpdC;  
String sURL; //File URL /i<g>*82  
long nStartPos; //File Snippet Start Position !PgYn  
long nEndPos; //File Snippet End Position oUqNA|l T  
int nThreadID; //Thread's ID ;AaF;zPV  
boolean bDownOver = false; //Downing is over \n5,!,A  
boolean bStop = false; //Stop identical 8`D_"3j3g\  
FileAccessI fileAccessI = null; //File Access interface 8dv1#F|  
1/ a,7Hl  
mEGMe@37  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException .*Z]0~ &
|  
{ .IqS}Rh  
this.sURL = sURL; A6d+RAx  
this.nStartPos = nStart; *\/UT  
this.nEndPos = nEnd; B?]^}r  
nThreadID = id; c~V\,lcI  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ??F{Gli"C`  
} #KIHq2:.4  
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public void run() xc!"?&\*  
{ \<5xf<{  
while(nStartPos < nEndPos && !bStop) o{
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{ B`vV[w?  
tNjrd}8s  
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try{ )9*WmFc+#  
URL url = new URL(sURL); *]LM2
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); NH{0KZ R  
httpConnection.setRequestProperty("User-Agent","NetFox"); uJ[
dO}  
String sProperty = "bytes="+nStartPos+"-"; \Tc$P#  
httpConnection.setRequestProperty("RANGE",sProperty); -6?5|\  
Utility.log(sProperty); N;htKcZ  
pCq{F*;  
)XD_Yq@E  
InputStream input = httpConnection.getInputStream(); )Z62xK2  
//logResponseHead(httpConnection); 9]Y@eRI<  
UZyo:*yB  
*aSFJK  
byte[] b = new byte[1024]; *ce h ]v  
int nRead; `0L!F"W  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) DV.m({?  
{ +iXA|L9=  
nStartPos += fileAccessI.write(b,0,nRead); 5yry$w$G)  
//if(nThreadID == 1) P^ a$?  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); "G<^@v9  
} 3h4>edM  
&ha39&I  
UW\.!TV  
Utility.log("Thread " + nThreadID + " is over!"); 'p<(6*,"  
bDownOver = true; yPL@uCzA@  
//nPos = fileAccessI.write (b,0,nRead); $zJ.4NA  
} )msqt!Ev  
catch(Exception e){e.printStackTrace ();} :5ji.g* 0  
} Q@2Smtu~c  
} x{=ty*E  
+;vfn>^!b  
/V,:gLpQ  
//打印回应的头信息 8 }-"&-X  
public void logResponseHead(HttpURLConnection con) WKN\*N<  
{ 6%)dsTAB  
for(int i=1;;i++) !4|7U\;  
{ HH>]"mv  
String header=con.getHeaderFieldKey(i); /@0wbA  
if(header!=null) X@TQD  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); )s!x)< d;  
Utility.log(header+" : "+con.getHeaderField(header)); ]]Wa.P~]O  
else F77~156  
break; 2
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} !fZxK CsQ  
} 4B) prQ3  
!.9NJ2'8  
L='GsjF0}  
public void splitterStop() KX{S8_  
{ 8}4V
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bStop = true; 9]l7j\L  
} m#Rll[  
O4 [[9  
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} sI#K01;"  
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F$d`Umqs;P  
/* z55P~p  
**FileAccess.java H1+
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*//文件访问(定位，写) sq*sbdE  
package NetFox; kFeuKSa^d  
import java.io.*; hMdsR,Iq  
OD{Rh(Id  
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public class FileAccessI implements Serializable{ tlc&Wx  
!tN]OQ)'  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 |XPT2eQ{  
RandomAccessFile oSavedFile;  QH;1*  
long nPos; ;|66AIwDe  
68d(6?OgW  
\!`*F:7]-  
public FileAccessI() throws IOException gJ:Z7b  
{ jytfGE:  
this("",0); ZfS-W&6Z  
} {um~]  
st~f}w@  
@va6,^)  
public FileAccessI(String sName,long nPos) throws IOException 7|*|xLrVY  
{ ]^R;3kU4Q  
oSavedFile = new RandomAccessFile(sName,"rw"); Jgb{Tl:r  
this.nPos = nPos; '\P6NszY~  
oSavedFile.seek(nPos); VDBP]LRF  
} 8MV=?  
ji:JLvf]%  
>{V]q*[/;Q  
public synchronized int write(byte[] b,int nStart,int nLen) m;k' j@:  
{ UfXqcyY(  
int n = -1; [/6IEt3}B  
try{ njX!Ez  
oSavedFile.write(b,nStart,nLen); 6*Rz}RQ  
n = nLen; Jva&"}Cb  
} [Cvo^cC  
catch(IOException e) hK3?m.>"g  
{ (eF
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e.printStackTrace (); D>PB|rS@  
} xrS;06$  
58{6kJ@  
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return n; nTyKZ(#u  
} Ub%5# <k|-  
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} O$<kWSC  
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b1R%JY7/S  
/* 6l<q  
**SiteInfoBean.java X*/jna"*  
*/ ZU5hHah.t  
package NetFox; 7jvf:#\LtL  
}]'Z~5T  
Quqts(Q)+  
public class SiteInfoBean { C5$1K'X@  
i.C+{QH  
ULNU'6  
private String sSiteURL; //Site's URL ^/U-(4O05*  
private String sFilePath; //Saved File's Path UzWf_
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private String sFileName; //Saved File's Name Tm 6<^5t  
private int nSplitter; //Count of Splited Downloading File N[~RWg  
)\8l6Gw  
/z.Y<xOc  
public SiteInfoBean() bODCC5
yL  
{//nSplitter的缺省值为5 [8v v[n/  
//default value of nSplitter is 5 sFsp`kf  
this("","","",5); =]K;"  
} @Xts}(L  
P{h;2b{  
Mpzt9*7R  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) }.>( [\q  
{ @2nar<  
sSiteURL= sURL; xrs?"]M[  
sFilePath = sPath; :<r.n "  
sFileName = sName; IQAV`~_G  
this.nSplitter = nSpiltter; ;`p+Vs8C  
5B< em  
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} @FKm
_q  
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^~'tQ}]!"  
public String getSSiteURL() 9w9[0BX#  
{ wM9HZraB<  
return sSiteURL; @GNNi?EY  
} i7_Nv
 
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|3<tDq@+  
public void setSSiteURL(String value) W<_9*{|E;  
{ W$>srdG0$  
sSiteURL = value; 5|z>_f.^pS  
} &@p_g8r#  
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OGpy\0%  
public String getSFilePath() ">_<L.,I  
{ % P .(L  
return sFilePath; K%h9'}pq>1  
} @~,&E*X! .  
1zqIB")s>  
+m8CN(c  
public void setSFilePath(String value) E!nEB(FD  
{ va 7I_J  
sFilePath = value; jeXP|;#Una  
} C,r[H5G#  
a|?&  
,<Zu4bww  
public String getSFileName() ,j E'd'$  
{ Fjch<gAofS  
return sFileName; n,/eT,48`  
}
}-jS0{i  
[CxnGeKK  
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public void setSFileName(String value) q#s:2#=  
{ %Z_/
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sFileName = value; <q\OREMsq  
} 69/aP=  
HEh,Cf7`'  
Se~<Vpo  
public int getNSplitter() Ck.LsL-  
{ rHYSS0*3  
return nSplitter; G8AT] =  
} #@%DY*w]v  
oHh~!#u  
sT8(f=^)8F  
public void setNSplitter(int nCount) E0HXB1"  
{ tV.qdy/]}  
nSplitter = nCount; LL% Aw)Q`  
} 1'Sr0 oEd3  
} ?|,dHqh{nM  
{o>51fXc)  
b^s978qn#  
/* >I*)0tE  
**Utility.java ={g.Fn(_  
*/ t"# .I?S0  
package NetFox; <9f;\+zA  
[Ey[A|g  
a9LK}xc={  
public class Utility { =f~8"j  
-nK\+bTL}  
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public Utility() G42J  
{ B8Vhl:p  
 vNWCv  
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} pzr\<U`  
'0b!lVe  
//线程睡眠 n<,:;0{  
public static void sleep(int nSecond) <DeC^[-P  
{ vC#_PI  
try{ fl@=h[g#t  
Thread.sleep(nSecond); x)}.@\&%  
} &JUHm_wd&S  
catch(Exception e) fI<|]c}P&J  
{ <b.O^_zQF  
e.printStackTrace (); yj$a0Rgkv  
} 2eC`^  
} ccR#<Pb6q  
s8:-*VR9  
//日志 9Gh:s6  
public static void log(String sMsg) [k~}Fe)x  
{ ;bYS#Bid{V  
System.err.println(sMsg); qQN|\u+co  
} %m/W4Nk  
}R&5Ye  
-tPia=^  
public static void log(int sMsg) p[LPi5  
{ VZz>)Kz:  
System.err.println(sMsg); iVaCXXf'  
} {u}d`%_.M  
} =# /BCL7  
hnYL<<AA  
r'F)8%  
/* /`kM0=MMa  
**TestMethod.java <Jc :a?ICe  
*/ %VH{bpS|i:  
package NetFox; ?zpN09e  
6lAHB*`  
'G)UIjl  
public class TestMethod { QJ4=*tX)  
ztEM>xsk  
_8 C:Md`  
public TestMethod() {,X}Btnwp  
{ ///xx/weblogic60b2_win.exe F[@M?  
try{ )lhPl  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); xfzGixA  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); < C1Jim  
SiteFileFetch fileFetch = new SiteFileFetch(bean); -bP_jIZF;g  
fileFetch.start(); uN;]Fv@Z  
} Ss~yy
0  
catch(Exception e){e.printStackTrace ();} k>.n[`>$6|  
$n#NUPzG+  
^]zC~LfG  
} ']&rPvkL  
zz m[sX}  
x{_3/4  
public static void main(String[] args) q)f-z\  
{ a%YohfsY?U  
new TestMethod(); lKSd]:3Xm  
} S_ER^Pkg  
} }K.2  
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