http断点续传简单实现（java)

/* 7w<e^H?  
**SiteFileFetch.java Dv*d$  
*/ q@^^jlHP  
package NetFox; 8RI'Fk{  
import java.io.*; X<D fzd oI  
import java.net.*; A"O\u=!  
}BUm}.-{u,  
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public class SiteFileFetch extends Thread { 95E#  
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SiteInfoBean siteInfoBean = null; //文件信息Bean :}R,a=N  
long[] nStartPos; //开始位置 )<f4F!?,A  
long[] nEndPos; //结束位置 ["#H/L]3  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 kTcW=AXu  
long nFileLength; //文件长度 !|l7b2NEz-  
boolean bFirst = true; //是否第一次取文件 !rF
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boolean bStop = false; //停止标志 gt9(5p  
File tmpFile; //文件下载的临时信息 NM9,AG  
DataOutputStream output; //输出到文件的输出流 >,QCKZH  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） M
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public SiteFileFetch(SiteInfoBean bean) throws IOException f62rm[  
{ 2+/r~LwbK  
siteInfoBean = bean; m] yUcj{F  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Eg&:yF}?(  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); `-e9#diQe  
if(tmpFile.exists ()) @u`W(Ow  
{ E+|K3EJ  
bFirst = false; %gQUog  
read_nPos(); NJSbS<O  
} "UreV  
else +p`BoF9~  
{ +_kA&Q(t  
nStartPos = new long[bean.getNSplitter()]; Ir-QD!!<  
nEndPos = new long[bean.getNSplitter()]; 5JEOLPS
  
} j{'_sI{{  
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} i=*H|)  
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public void run() }K@m4`T  
{ pKpB  
//获得文件长度 YK[2KTlo  
//分割文件 #t;]s<  
//实例FileSplitterFetch =|``d-  
//启动FileSplitterFetch线程 |5%T)  
//等待子线程返回 0e+#{k  
try{ + kT ]qH  
if(bFirst) x/CM)!U)  
{ NP\mzlI~@  
nFileLength = getFileSize(); |O6/p7+.  
if(nFileLength == -1) &tvtL  
{ l$pz:m]Id  
System.err.println("File Length is not known!"); (sQXfeMz  
} k7Qs#L  
else if(nFileLength == -2) cD6^7QF  
{ Xp9I3n
d|  
System.err.println("File is not access!"); dt@c,McN|Q  
} {d*OJ/4  
else 54Rp0otv  
{ 37kVJQcA1  
for(int i=0;i<nStartPos.length;i++) {|hg3R~A  
{ [T,^l#S1  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); |h
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} 8C8S)
;  
for(int i=0;i<nEndPos.length-1;i++) EnlAgL']|  
{ 7I'C'.6iM  
nEndPos = nStartPos[i+1];
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} W>i%sHH6  
nEndPos[nEndPos.length-1] = nFileLength; CEI"p2  
} `7w-_o %  
} jk&xzJH.  
RZV6;=/  
]b;m~|9  
//启动子线程 2/r8%Sq  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; B7[d^Y60B  
for(int i=0;i<nStartPos.length;i++) d8vf kVB  
{ [ 5}Q  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), `j@1]%&z  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Q17d
cgd  
nStartPos,nEndPos,i); C{pOGc@  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 3sdL\  
fileSplitterFetch.start(); ap )B%9  
} ur8+k4]\"  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ,G%UU~/a  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); }R#W<4:  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", u-,}ug|  
nEndPos = " + nFileLength); ceE]^X;p  
// fileSplitterFetch[nPos.length-1].start(); g assOd  
uOLShNo  
B8T$<  
//等待子线程结束 F""9O6u  
//int count = 0; Ch>F11kC  
//是否结束while循环 30uPDDvar  
boolean breakWhile = false; /m"/#; ^l  
lJ-PW\P  
3r kcIVO  
while(!bStop) k*fU:q1  
{ +m%%Bz>  
write_nPos(); hk4t #Km  
Utility.sleep(500); i^%$ydg  
breakWhile = true; )e?&'wa>  
|{YN3"qN  
5F~l;zT  
for(int i=0;i<nStartPos.length;i++) ZK^cG'^2|  
{ )ciP6WzzbI  
if(!fileSplitterFetch.bDownOver) rvd$4l^  
{ hOAZvrfQ4  
breakWhile = false; `2s@O>RV  
break; 70c]|5  
} f<@!{y2Xe  
} h
vw9i7#  
if(breakWhile) Q!1;xw~  
break; TSP%5v;Dh  
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yKV{V?h?  
//count++; fx_#3=bXi  
//if(count>4) |^1U<'oM#  
// siteStop(); 8J(j}</>a  
} RtMI[  
H/O.h@E4X  
f"5O'QHGQK  
System.err.println("文件下载结束！"); ResU5Ce~  
} {\l  
catch(Exception e){e.printStackTrace ();} K4!-%d$  
} yQ[;y~W  
}%jF!d  
OT])t<TF6  
//获得文件长度 J2W-l{`r<  
public long getFileSize() ]5Uuz?:e  
{ ^Qs}2%  
int nFileLength = -1; V^2_]VFj  
try{ crM5&L9zF  
URL url = new URL(siteInfoBean.getSSiteURL()); | ;tH?E  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); JnBUW"  
httpConnection.setRequestProperty("User-Agent","NetFox"); 
o]e,5]  

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int responseCode=httpConnection.getResponseCode(); hC:'L9Y  
if(responseCode>=400) ,&t+D-s<f  
{ M5`v^>  
processErrorCode(responseCode); 7s|'NTp  
return -2; //-2 represent access is error ff#7}9_mh  
} uYU
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7]h%?W!  
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String sHeader; J6Z[c*W  
NfgXOLthM  
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for(int i=1;;i++) }\"EI<$s  
{ '$tCA
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//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Ww]$zd-bo  
//Utility.log(in.readLine()); }T?X6LA$I8  
sHeader=httpConnection.getHeaderFieldKey(i); bwsKdh  
if(sHeader!=null) a1cX+{W  
{ .a*?Pal@@  
if(sHeader.equals("Content-Length")) <XdnVe1  
{ R}&?9tVRR  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); /%T/@y  
break; 8 1,N92T5  
} ]E
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} gQ+]N*.  
else Th)
  
break; c+:ZmrP/  
} 0@ `]m  
} 0j$\k|xFXZ  
catch(IOException e){e.printStackTrace ();} %F*9D3^h  
catch(Exception e){e.printStackTrace ();} LE\*33k_  
.p#kW:zspA  
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Utility.log(nFileLength); voa)V1A/]  
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V%,,GmiU]  
return nFileLength; q)q3p  
} `~GXK  
"-4|HA  
C;BO6$*_e  
//保存下载信息（文件指针位置） k6tCfq;  
private void write_nPos() fv;Q*; oC&  
{ QQJGqM3a2  
try{ U2VEFm6  
output = new DataOutputStream(new FileOutputStream(tmpFile)); CmU@8-1  
output.writeInt(nStartPos.length); V3,C5KKk&z  
for(int i=0;i<nStartPos.length;i++) {wSi?;[Gq  
{ VfnL-bDGV  
// output.writeLong(nPos); 49qa  
output.writeLong(fileSplitterFetch.nStartPos); /J`}o}  
output.writeLong(fileSplitterFetch.nEndPos); ?JuJu1  
} ?^&ih:"  
output.close(); /X}1%p  
} H
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catch(IOException e){e.printStackTrace ();} )~'UJPK  
catch(Exception e){e.printStackTrace ();} m$8siF{<q  
} 1mFH7A($  
}8O9WS  
5_^d3LOT0x  
//读取保存的下载信息（文件指针位置） c&c  
private void read_nPos() &9e  
{ &8VH m?h  
try{ pSx5ume95"  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); _S_,rTf&  
int nCount = input.readInt(); {|9knP  
nStartPos = new long[nCount]; h,[L6-n  
nEndPos = new long[nCount]; ?q!4REM  
for(int i=0;i<nStartPos.length;i++) l$u52e!7  
{ <@J$hs9s  
nStartPos = input.readLong(); U6JD^G=qR,  
nEndPos = input.readLong(); `^#Rwn#  
} h7]+#U]mi
 
input.close(); < F5VJ  
} w
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catch(IOException e){e.printStackTrace ();} N XB8u6  
catch(Exception e){e.printStackTrace ();} MR
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} 6*,55,y  
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private void processErrorCode(int nErrorCode) g}~s"Sz  
{ *)[fGxz \  
System.err.println("Error Code : " + nErrorCode); 60{G 4b)  
} m{>1#1;$t  
&>-'|(m+2  
$NCvF'  
//停止文件下载 bWL!=  
public void siteStop() w/NT5  
{ sm##owI  
bStop = true; $mxG-'x%K  
for(int i=0;i<nStartPos.length;i++) 'e:4  
fileSplitterFetch.splitterStop(); c@>ztQU*  
I=DVMG|  
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} &pK0>2  
} g_4%M0&AX  
//负责部分文件的抓取  +At[[  
**FileSplitterFetch.java H@- GYX"4  
*/ cRI2$|  
package NetFox; Dp['U
  
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import java.io.*; KyIUz9$  
import java.net.*; <=CABWO.  
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$  
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public class FileSplitterFetch extends Thread { p` ~=
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-75mgOj.#  
<uU<qO;6  
String sURL; //File URL lOA EM  
long nStartPos; //File Snippet Start Position 2KO`+
  
long nEndPos; //File Snippet End Position jNbVp{%/S}  
int nThreadID; //Thread's ID E$_zBD%  
boolean bDownOver = false; //Downing is over v2gk1a&  
boolean bStop = false; //Stop identical L=54uCv Q  
FileAccessI fileAccessI = null; //File Access interface UDZ0ne0-  
r5[pT(XT]  
0.m-}  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException zWPX  
{ (k+*0.T&?  
this.sURL = sURL; Q~.t8g/  
this.nStartPos = nStart; 7Z9'Y?[m  
this.nEndPos = nEnd; h[Sd3Z*  
nThreadID = id; T!?tyW  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 N, u]2,E  
} =84EX<B  
v?8i;[  
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public void run() ;4dFL\KU  
{ W.s8!KH:  
while(nStartPos < nEndPos && !bStop) &b>&XMIK  
{ S/*\j7cj  
]Vj($O:  
@}PXBU   
try{ qh W]Wd"g  
URL url = new URL(sURL); )Vy0V=  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); |3FGMg%  
httpConnection.setRequestProperty("User-Agent","NetFox"); #Rfcp
!  
String sProperty = "bytes="+nStartPos+"-"; #oiU|>3Y  
httpConnection.setRequestProperty("RANGE",sProperty); S;t`C~l
\  
Utility.log(sProperty); 3S#p4{3  
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InputStream input = httpConnection.getInputStream(); 5"G-r._  
//logResponseHead(httpConnection); myVa5m!7Q  
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byte[] b = new byte[1024]; >jiez,  
int nRead; z.(DDj  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 2::YR?  
{ QoUdTIIL  
nStartPos += fileAccessI.write(b,0,nRead); K2Ro0  
//if(nThreadID == 1) 'aV'Am+:  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); *@^@7`W  
} teb(gUy}L6  
czT2f  
8kcMgCO  
Utility.log("Thread " + nThreadID + " is over!"); <L*`WO]\l  
bDownOver = true; 7l/ZRz}1  
//nPos = fileAccessI.write (b,0,nRead); :J@3:+sr  
} tBJ4lb  
catch(Exception e){e.printStackTrace ();} A4rMJ+!5  
} cR!M{U.q  
} a-S tOO5s  
dg~lz80  
8PVjNS/  
//打印回应的头信息 p-\->_9)y`  
public void logResponseHead(HttpURLConnection con) 31 <0Nw;l  
{ .9Cy<z  
for(int i=1;;i++) )HI
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{ $aU.M3  
String header=con.getHeaderFieldKey(i); du~V=%9  
if(header!=null) V'>Plb.A  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); *aS+XnT/  
Utility.log(header+" : "+con.getHeaderField(header)); Nr]Fh  
else `9^+KK"  
break; 479X5Cl  
} U/AiI;Ne  
} <%d!Sk4  
}[lP^Qs  
A/:_uqm4  
public void splitterStop() AWMJ/E*T  
{ 4'`P+p"A  
bStop = true; U$OI]Dd9  
} QD3tM5(Yr  
})70S8k  
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} yZ[g2*1L  
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vOz1& |;D  
/* b+:J?MR;}  
**FileAccess.java VZr:yE  
*//文件访问(定位，写) -@_v@]:  
package NetFox; 6hd<ys?  
import java.io.*; l"}_+5  
bFajK;  
qF`
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public class FileAccessI implements Serializable{ ,>b>I#{  
*5k40?w  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 of_y<dd[G  
RandomAccessFile oSavedFile; ^Z;zA@[wt  
long nPos; &*7KQd  
F{a;=h#@Q  
/; Bmh=  
public FileAccessI() throws IOException w
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{ w5%i  
this("",0); e*lL.  
} njX$?V   
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public FileAccessI(String sName,long nPos) throws IOException UWKgf? _  
{ cXqYO|3/M  
oSavedFile = new RandomAccessFile(sName,"rw"); YVDFcN9v  
this.nPos = nPos; ]r|oNGD)G  
oSavedFile.seek(nPos); p+V#86(3  
} %2zmc%]r  
m?<E >-bI  
/ 'qoKof  
public synchronized int write(byte[] b,int nStart,int nLen) HVHv,:bPo  
{ wTa u.Bo  
int n = -1; xxu  
try{ kc^,V|Nbq6  
oSavedFile.write(b,nStart,nLen); ,oA<xP-*  
n = nLen; ^r&)@R$V  
} Wvr{l  
catch(IOException e) {JP q.A  
{ kzRJzJquP  
e.printStackTrace (); W/ Q*NB  
} ?PT>V,&  
<R /\nYXz  
qt~=47<d  
return n; [ncK+rGAc  
} I} jgz  
[^5;XD:%&l  
rR#Ditn^  
} !o /=,ZIx  
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^'V :T Y  
/* v.jxG{~.  
**SiteInfoBean.java m|aK_  
*/ + t5SrO!`  
package NetFox; ;ItH2Lw<&  
uX6yhaOp|  
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public class SiteInfoBean { h= sNj  
W#p7M[  
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private String sSiteURL; //Site's URL
C1k< P  
private String sFilePath; //Saved File's Path {rUg,y{v  
private String sFileName; //Saved File's Name "0An'7'm  
private int nSplitter; //Count of Splited Downloading File  oBkhb  
y QW7ng7D0  
"B_3<RSL  
public SiteInfoBean() *5%vU|9b  
{//nSplitter的缺省值为5 -&5YRfr!  
//default value of nSplitter is 5 N,Eap KG  
this("","","",5); K*>%,mP$i  
} )XN_|zCk  
e73=*~kfR  
hIJtu;}zU  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) C`[<6>&y  
{ fST.p|b7  
sSiteURL= sURL; [IL*}M!  
sFilePath = sPath; MuoE~K2  
sFileName = sName; dHc\M|HCC  
this.nSplitter = nSpiltter; e&}W#  
h'y%TOob  
&lQ%;)
'  
} AW]\n;f  
OETo?Wg1Z  
W[ l  
public String getSSiteURL() Eomfa:WL  
{ 'hpOpIsHa  
return sSiteURL; V`Cyx^P  
} xyp{_ MZ  
\}Jznzx;
 
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public void setSSiteURL(String value) !5`MiH  
{ M@Th^yF+8H  
sSiteURL = value; +Nt4R:N  
} XO+BZB`F  
;c!> =  
%{u@{uG0'3  
public String getSFilePath() JrzPDb`m  
{ 2XP }:e  
return sFilePath; u8Ys2KLpL  
}  %?ElC  
n1s
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a-{|/ n%  
public void setSFilePath(String value) fAsb:P  
{ [o)K1>>7  
sFilePath = value; GX>8B:]o|  
} &dyQ6i$],  
1}(22Q;  
xl&@g)Jj  
public String getSFileName() V]7/hN-Y}  
{ pY31qhoZ.  
return sFileName; /<rvaR  
} )bUnk+_  
(GJtTp~2C4  
)UzJ2Pa<+_  
public void setSFileName(String value) UB$}`39@  
{ .j]tzX  
sFileName = value; $vs],C"pX  
} 8 v/H;65  
R"B{IWQi  
)/raTD  
public int getNSplitter() w1/QnV  
{ tOIqX0dWd  
return nSplitter; Y2`sL,'h  
} dyQ7@K.E  
^ja]e%w#  
V(';2[)  
public void setNSplitter(int nCount) @6;OF5VsQ  
{ *:%&z?<Fw  
nSplitter = nCount; iLy^U*yK  
} (?z?/4>7<  
} odhcD;^X1  
<.h7xZ  
)N.3Q1g-  
/* LU
6R"c11  
**Utility.java K9N31'  
*/ lC5zqyG  
package NetFox; ,6^<Vg  
@Jd&[T27Lr  
\BHZRytQF  
public class Utility { yYz{*hq  
OyO<A3  
v=k+MvX  
public Utility() $kUB%\`  
{ lR?y tIY  
KL$.E!d  
|8` }8vo)  
} gj^)T_E_  
PQaTS*0SXJ  
//线程睡眠 ZqclmCi  
public static void sleep(int nSecond) a6Vfd&  
{ w%L4O;E]*{  
try{ z^9oaoTl  
Thread.sleep(nSecond); &M|rRd~*  
} ?`RlY
u  
catch(Exception e) SdnnXEB7  
{ gC$_yd6m L  
e.printStackTrace (); 8ZtJvk`  
} ilL%  
} )Xdq+$w.  
<X*oW".  
//日志 !oH{=.w  
public static void log(String sMsg) ?dJd7+A  
{ h,\{s_b  
System.err.println(sMsg); `+w= p7ET  
} wR_mJMk_  
"M/c0`>C!i  
kn:hxdZ  
public static void log(int sMsg) i*$+>3Q-  
{ Sh#N5kgD  
System.err.println(sMsg); P5my]4|x  
} |uy@v6  
} JV_`E_!  
+2MF#{ tS  
#?)6^uTW  
/* <lzC|>BG  
**TestMethod.java j&Hui>~  
*/
DOyO`TJi  
package NetFox; A.*e8a/6X  
FWu:5fBZY  
e (]]  
public class TestMethod { A{>w5T  
bIm4s  
r(Sh  
public TestMethod() 3>n&u,Xe  
{ ///xx/weblogic60b2_win.exe yr'-;-u  
try{ 0j8fU7~6S  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); e(wc [bv  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); A@o
7  
SiteFileFetch fileFetch = new SiteFileFetch(bean); -aBhN~  
fileFetch.start(); wfO-bzdw  
} }h`z2%5o  
catch(Exception e){e.printStackTrace ();} i\lvxbp  
]]y>d!  
z?13~e[D  
}  0Y!"3bw|  
oi`L ;w|]  
Q=! lbW  
public static void main(String[] args) iZk4KX  
{ { 1~]}K2  
new TestMethod(); r1F5'?NZ(0  
} cA
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} `'|6b5`2j  
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