http断点续传简单实现（java)

/* Rq9gtx8,=  
**SiteFileFetch.java !INr  
*/ eo80L  
package NetFox; (BGipX4  
import java.io.*; w}i.$Qt  
import java.net.*; >6dgf
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4<Y?#bm'  
gf=*m"5  
public class SiteFileFetch extends Thread { Pn#Lymxh_a  
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[~o3S$C&7  
SiteInfoBean siteInfoBean = null; //文件信息Bean -+=8&Wa  
long[] nStartPos; //开始位置 KJ~pY<a?  
long[] nEndPos; //结束位置 {HU48v"W  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 gn%"df
m  
long nFileLength; //文件长度 : L>d]Hn  
boolean bFirst = true; //是否第一次取文件 `otQ'e~+t  
boolean bStop = false; //停止标志 *k}d@j,*"  
File tmpFile; //文件下载的临时信息 ~h/U ;Da  
DataOutputStream output; //输出到文件的输出流 UGMdWq  
0#7dm9  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ex1ecPpN  
public SiteFileFetch(SiteInfoBean bean) throws IOException LQjqwsuN{  
{ x9e 9$ww}  
siteInfoBean = bean; vKC>t95  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); )'g vaT  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); hMQ
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if(tmpFile.exists ()) 0>`69&;g|  
{ sm
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bFirst = false; z)B=<4r  
read_nPos(); >gE_?%a[  
} R[c_L=  
else ;gyE5n-{  
{ 34=0.{qn  
nStartPos = new long[bean.getNSplitter()]; D4|_?O3|m  
nEndPos = new long[bean.getNSplitter()]; WKf~K4BL>  
} -UVWs2W'$  
rUO{-R  
7,zARWB!?  
On^#x]  
} 8{YxUD  
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public void run() #L)rz u  
{ LcXMOT)s  
//获得文件长度 'w2;oO  
//分割文件 &}cie"\L  
//实例FileSplitterFetch DbN'b(+  
//启动FileSplitterFetch线程 Q [{vU  
//等待子线程返回 4=Ey\Px  
try{
1|VJND  
if(bFirst) NP8TF*5V  
{ /HRaX!|E#  
nFileLength = getFileSize(); x_K%  
if(nFileLength == -1) ~#CCRUhM  
{ J (h>  
System.err.println("File Length is not known!"); =+p+_}C  
} c0 |p34  
else if(nFileLength == -2) : [y(<TLw  
{ v(iUo&Ge  
System.err.println("File is not access!"); ho1F8TG=  
} 4B`Rz1QBy  
else MQ44uHJ  
{ 5qy}~dQ  
for(int i=0;i<nStartPos.length;i++) 3o>t~Sfi  
{ ^|C|=q~:  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); F0Hbklr  
} &[kgrRF@HU  
for(int i=0;i<nEndPos.length-1;i++) Kxn7sL$]=F  
{ o3=kF  
nEndPos = nStartPos[i+1]; u$#7W>R  
} 1RA$hW@}  
nEndPos[nEndPos.length-1] = nFileLength;
)^TQedF  
} PS6`o  
} cy4'q?r  
Pc'?p  
&pm{7nH  
//启动子线程 `qTY  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length];  >9`ep7  
for(int i=0;i<nStartPos.length;i++) m+vEs,W.  
{ i7V~LO:gq  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Ao T7s
y7  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), L])w-  
nStartPos,nEndPos,i); jhv1 D'>6  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); cqx1NWlY  
fileSplitterFetch.start(); }=a4uCE  
} `Ny8u")=  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 1 1CJT  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 5>)jNtZ  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", / JB4#i7  
nEndPos = " + nFileLength); )*h~dx_cm  
// fileSplitterFetch[nPos.length-1].start(); 9#ft;c  
$x;h[,y   
$sZHApJV+  
//等待子线程结束 *a!!(cZZ  
//int count = 0; $0T"YC%  
//是否结束while循环 4-_lf(#i  
boolean breakWhile = false; P-[K*/bPw  
"\;wMR{  
Bq@wS\W>b}  
while(!bStop) s2~dmZ_B|_  
{ *GP_ut%  
write_nPos(); GDp p`'\  
Utility.sleep(500); !T#y r)  
breakWhile = true; p^P y,  
)H)Udhz  
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for(int i=0;i<nStartPos.length;i++) /T[ICd2J  
{ C
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if(!fileSplitterFetch.bDownOver) e"#D){k#  
{ 4Z9wzQ>  
breakWhile = false; ~+C?][T  
break; e oSM@Isu  
} !m(L0YH  
} J"/z?!)IB  
if(breakWhile) JyC&L6[]Z  
break; +wozjjc  
 /;6@M=6u  
 ii  y3  
//count++; R2THL  
//if(count>4) (M,VwwN  
// siteStop(); <[:7#Yo g  
} 2pa3}6P+  
o MkY#<Q}  
3n(gfQo-o  
System.err.println("文件下载结束！"); ggc?J<Dv  
} w/5^R  
catch(Exception e){e.printStackTrace ();} D"4&9"CU  
} V9u\;5oL  
) Zo_6%  
9,f<Nb(\  
//获得文件长度 L8wcH  
public long getFileSize() @[tV_Z%,b  
{ 8sIA;r%S  
int nFileLength = -1; AAq=,=:R<  
try{ F(9 Y/UXH  
URL url = new URL(siteInfoBean.getSSiteURL()); .*-w UBr  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); B36puz 0{  
httpConnection.setRequestProperty("User-Agent","NetFox"); :dIQV(iW  
'z}M[h K]  
68<Z\WP  
int responseCode=httpConnection.getResponseCode(); ~X<cG=p~u  
if(responseCode>=400) 7[v@*/W@  
{ !{tiTA  
processErrorCode(responseCode); )9L pX  
return -2; //-2 represent access is error F4E3c4 81  
} rjHIQC C  
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nIQ&gbfO  
String sHeader; 2?- 0
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for(int i=1;;i++) Ocwp]Mut&  
{ x2;i< |  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); .um&6Q=2<  
//Utility.log(in.readLine()); ^M"z1B]  
sHeader=httpConnection.getHeaderFieldKey(i); bk"k&.C^+  
if(sHeader!=null) {&=qM!2e  
{ w
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if(sHeader.equals("Content-Length")) wK'!xH^  
{ OssR[$69  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); TT2cOw  
break; D"XX920$~  
} \!JS7!+  
} EEs-&  
else WAB0e~e:|Q  
break; }PQSCl^I  
} r}0C8(oq  
} AR~$MCR]"k  
catch(IOException e){e.printStackTrace ();} =v4r M0m,  
catch(Exception e){e.printStackTrace ();} sCtw30BL  
7ec0Xh1  
p/k<wCm6  
Utility.log(nFileLength); o4%Vt} K  
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/pN'K5@  
return nFileLength; a WeBav}_  
} ~z K@pFeH  
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twtkH~`"Q  
//保存下载信息（文件指针位置） O5qW*r'  
private void write_nPos() u-QO>3oY6  
{ 2zKo  
try{ 1<a@p}  
output = new DataOutputStream(new FileOutputStream(tmpFile)); y=9Dxst"V  
output.writeInt(nStartPos.length); p2x1xv  
for(int i=0;i<nStartPos.length;i++) n{^<&GWox  
{
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// output.writeLong(nPos); q11QAx4p  
output.writeLong(fileSplitterFetch.nStartPos); uKbHFF  
output.writeLong(fileSplitterFetch.nEndPos); b H"}w$!>r  
} j&dx[4|m:h  
output.close(); vS$oT]-hKE  
} &{zwM |Q@?  
catch(IOException e){e.printStackTrace ();} dY/u<4  
catch(Exception e){e.printStackTrace ();} +[whh  
} 4e+BqCriC*  
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//读取保存的下载信息（文件指针位置） ,](v?v.[4  
private void read_nPos() X
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{ B:?#l=FL  
try{ \f/#<|Hm  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); *H5PT  
int nCount = input.readInt(); CZJHE>  
nStartPos = new long[nCount]; BbrT f"`  
nEndPos = new long[nCount]; Y9i9Uc.]  
for(int i=0;i<nStartPos.length;i++) Nmp>UE,7[  
{ -@ZzG uS(  
nStartPos = input.readLong(); )X~Pr?52?  
nEndPos = input.readLong(); %j*k  
} *D?((_+  
input.close(); [,<\RviI  
} (Ffb&GL  
catch(IOException e){e.printStackTrace ();} ZcMj=#i  
catch(Exception e){e.printStackTrace ();} )W8L91-  
} @7
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W$" Y%^L  
h L]8e>a?  
private void processErrorCode(int nErrorCode) z;dcAdz9  
{ k,,!P""  
System.err.println("Error Code : " + nErrorCode); gX@nPZjg  
} psIkG0 &  
Hz}+SAZ  
&Y,Q>bu  
//停止文件下载 +{xMIl_  
public void siteStop() G{kj}>kS_  
{ ^:4L6  
bStop = true; (Sth:{;  
for(int i=0;i<nStartPos.length;i++) H>
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fileSplitterFetch.splitterStop(); J>=1dCK  
k42b:W5%  
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} :be:-b%K  
}
Y*@|My`  
//负责部分文件的抓取 !8xKf*y  
**FileSplitterFetch.java zmf"I[)  
*/ /Hv*K&}M  
package NetFox; ,b<9?PM  
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5<89Af&&K8  
import java.io.*; cMDRWh  
import java.net.*; Ia=_78MgZ  
<S]KaDu^  
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public class FileSplitterFetch extends Thread { HEBqv+bG  
Z)m
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v9%nau4  
String sURL; //File URL yp=|7  
long nStartPos; //File Snippet Start Position pC*BA<?Rg  
long nEndPos; //File Snippet End Position 0VzXDb>`  
int nThreadID; //Thread's ID 2m_'z  
boolean bDownOver = false; //Downing is over aZ`<PdA  
boolean bStop = false; //Stop identical .Y!;xB/  
FileAccessI fileAccessI = null; //File Access interface y7/PDB\he  
yeh8z:5Z O  
4,2(nYF  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException MZT6g.ny  
{ jCzGus!rM  
this.sURL = sURL; @l'G[jN5  
this.nStartPos = nStart; #2\8?UPd  
this.nEndPos = nEnd; :.#z  
nThreadID = id; 7p^@;@V  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 rO0ZtC{K  
} |/VL35b  
 ]nUR;8  
H+a~o=/cR  
public void run() ;SgD 5Ln}  
{ *B1x`=  
while(nStartPos < nEndPos && !bStop) }sv!=^}BY3  
{ YMT8p\#rp  
0<g<GQ(E  
& g:%*>7P  
try{ 7i8eg*Gl  
URL url = new URL(sURL); *C\(wL  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); e^QVn\<c  
httpConnection.setRequestProperty("User-Agent","NetFox"); @g4Shlx|  
String sProperty = "bytes="+nStartPos+"-"; !\^jt%e&  
httpConnection.setRequestProperty("RANGE",sProperty); Y]N~vD  
Utility.log(sProperty); ^]6M["d/p  
t05_Px!mW  
RdgVBG#Z1  
InputStream input = httpConnection.getInputStream(); F;u7A]H^  
//logResponseHead(httpConnection); &y7
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L\YKdUL  
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byte[] b = new byte[1024]; ;7rd;zJ  
int nRead; 4QE=f(u;h  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 7{pIPmJ  
{ /HkFlf
Pd  
nStartPos += fileAccessI.write(b,0,nRead); bni)Qw  
//if(nThreadID == 1) ;o[rQ6+  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); \PbvN\L  
} R:~(Z?  
?q_^Rj$  
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Utility.log("Thread " + nThreadID + " is over!"); Q&xjF@I  
bDownOver = true; zsDocR   
//nPos = fileAccessI.write (b,0,nRead); daslaa_A  
} ca(U!T68  
catch(Exception e){e.printStackTrace ();}  `?|Rc  
} l-}KmZ]  
} +Q)ULnie e  
x? N.WABr;  
C/G]v*MBQ  
//打印回应的头信息 aG(hs J)  
public void logResponseHead(HttpURLConnection con) w9f _b3  
{ hGI+:Js6  
for(int i=1;;i++) 2ev*CX6.  
{ @4drjT  
String header=con.getHeaderFieldKey(i); Z\Z,,g+WL  
if(header!=null) *YtB )6j  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); r?p[3JJ;mG  
Utility.log(header+" : "+con.getHeaderField(header)); 537?9  
else (WRMaI72(  
break; Fu7M0X'p  
} fN)
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} o
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mu[Op*)  
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public void splitterStop() 2no$+4+z  
{ o5swH6Y.)J  
bStop = true; iA'As%S1  
} /[K_ &  
m`y9Cuk  
S`m,S4-eD  
} j13DJ.xu  
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9 |
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/* BLn_u,3  
**FileAccess.java $.rzc]s  
*//文件访问(定位，写) R,t$"bOd  
package NetFox; S2K#[mDG  
import java.io.*; A&zS'toU  
sI,W%I':d  
rp's
 
public class FileAccessI implements Serializable{ `G!M>h@  
j*400  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ^lj7(  
RandomAccessFile oSavedFile; FW..mD9)}  
long nPos; 3[d>&xk@$  
Gb2L }  
4^*,jS-9g}  
public FileAccessI() throws IOException q.Jsf+  
{ ])w[

  
this("",0); |=6_ xRyr  
} r37[)kJ  
UDEj[12S  
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public FileAccessI(String sName,long nPos) throws IOException 8(f
:U@BS  
{ 6>`c1 \8f  
oSavedFile = new RandomAccessFile(sName,"rw"); +G*JrwJ&=  
this.nPos = nPos; c_.-b=zm  
oSavedFile.seek(nPos); 9QwKakci  
} mwC=o5O  
bsS:"/?>  
]<XR]FHx)  
public synchronized int write(byte[] b,int nStart,int nLen) v^N`IJq  
{ ~"K,7sw!Y  
int n = -1; O
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try{ +=BAslk  
oSavedFile.write(b,nStart,nLen); S6xgiem  
n = nLen; 7 oQ[FdRn*  
} mi,&0xDea  
catch(IOException e) =0qpVFvU  
{ 4!.(|h@  
e.printStackTrace (); ,q#0hy%5/  
} {X~gwoz  
}V]R+%:w@  
F;q#&  
return n; Kibr ]w  
} Hfym30  
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} -/
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/* x=q;O+7]  
**SiteInfoBean.java ~" i0x
 
*/ 1}%B%*N  
package NetFox; T{+Z(L  
B<?wh0  
3Ot~!AlR  
public class SiteInfoBean { RY9V~8|M  
c{3wk7  
E"~2./+rd  
private String sSiteURL; //Site's URL /Ncm^b4  
private String sFilePath; //Saved File's Path 9X$ma/P[  
private String sFileName; //Saved File's Name CW&.NT  
private int nSplitter; //Count of Splited Downloading File 2`GOJ,$  
eE GfM0  
tDg}Ys=4K>  
public SiteInfoBean() )2IH 5  
{//nSplitter的缺省值为5 [ic87
0_  
//default value of nSplitter is 5 O@V%Cu  
this("","","",5); r!PpUwod  
} ^T::-pN*  
iBTYY{-wF  
S!v(+|  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) <{5EdX  
{ _Q[$CcDEE  
sSiteURL= sURL; Om;&_!
i  
sFilePath = sPath; 42J{aJVH  
sFileName = sName; $D'-k]E[H  
this.nSplitter = nSpiltter; BZ54*\t  
{X(:jAy  
`-h8vj5uG  
} h:Gu`+D>W  
z`UhB%-?  

>TkE~7?l  
public String getSSiteURL() 6 5N~0t  
{ #X 52/8G  
return sSiteURL; j)C,%Ol  
} H,nec<Jp  
o%9*B%HO/  
{(U %i\F\  
public void setSSiteURL(String value) {!t7[Ctb  
{ eq(am%3~  
sSiteURL = value; fk1ASV<rN  
} ojvj}ln  
'(bgs  
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public String getSFilePath() .sC?7O=  
{ (8.Z..PH  
return sFilePath; Y2o?gug  
} |KSy`lY-j>  
aT>'.*\]  
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public void setSFilePath(String value) if|+EN%  
{ <Ln1pV~k  
sFilePath = value; |7y

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} #]nx!*JNZ  
&e6CJ  
&wD;SMr<  
public String getSFileName() 35E_W>n  
{ :8CvRO*<  
return sFileName; 1$M@]7e+!+  
} wr[,  
At7>V-f}  
&l3iV88  
public void setSFileName(String value) Oo"^%F~%  
{ Tb3J9q+ya  
sFileName = value; O+y-}7YX  
} Vn*tpbz  

> ;/l)qk,  
28 8XF9B^  
public int getNSplitter() /"eey(X  
{ Jn{OWw2  
return nSplitter; .C
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} f7m%|v!  
B!vmQR*1  
 IiY/(N+J  
public void setNSplitter(int nCount) +L7n<U3  
{ e,t(q(L  
nSplitter = nCount;
(M*FIX  
} U}[I   
} 5$V_
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^h69Kr#d4  
0NS<?p~_S  
/* /YZr~|65  
**Utility.java
E\Rhz]G(  
*/ x>Zn?YR,"  
package NetFox; NR`C(^}  
{zMU#=EC  
"?V0$-DR  
public class Utility { |&RU/a  
6@rMtQfI  
Q_[ 3`jl  
public Utility() dBz/7&Q   
{
S:h{2{  
0u;4%}pD  
 Vh_P/C+  
} 9I}-[|`u  
,6-:VIHQ  
//线程睡眠 Wk)OkIFR  
public static void sleep(int nSecond) \O2Rhz  
{ 3B84^>U<  
try{ U4d:] z  
Thread.sleep(nSecond); IZpP[hov  
} ibj87K  
catch(Exception e) vX/T3WV  
{ A"L&a l$i  
e.printStackTrace (); gt@m?w(  
} -*1J f&  
} #qK:J;Sn3  
G3Z)Z)N  
//日志 }H^+A77v  
public static void log(String sMsg) KV(Q;~8"X  
{ >CHrg]9  
System.err.println(sMsg); <J)]mh dm  
} '@_d(N1jTw  
|olA9mp|]  
nAv#?1cjz  
public static void log(int sMsg) aDU<wxnSvO  
{ k$blEa4  
System.err.println(sMsg); sB7# ~pA  
} Zy`m!]G]80  
} h1de[q
)  
16=sij%A  
Sc;BCl{=|  
/* 4K\G16'$v  
**TestMethod.java 8Vr%n2M  
*/ AE[b},-[  
package NetFox; JRB9rSN^  
LRL,m_gt  
}
\B><E{G  
public class TestMethod { pFOx>u2`a  
0Tx6zO  
qLD ?juas  
public TestMethod() Q'=x|K#xj  
{ ///xx/weblogic60b2_win.exe dYJ(!V&  
try{ y [}.yyye  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Mk"^?%PxT  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); H?yK~bGQ  
SiteFileFetch fileFetch = new SiteFileFetch(bean); l9{hq/V  
fileFetch.start(); GeH#I5y  
} z&zP)>Pv  
catch(Exception e){e.printStackTrace ();} 8\+uec]k  
H#,W5EJzM  
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} l+KY)6o  
*4\:8  
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public static void main(String[] args) !fE`4<|?  
{ */`ki;\A  
new TestMethod(); t}r' k/[  
} 01t1Z}!y  
}
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