http断点续传简单实现（java)

/* Ka-p& Uv1<  
**SiteFileFetch.java :BZ0 7`9  
*/ h/ep`-YaH  
package NetFox; Je7RrCz  
import java.io.*; I4e+$bU3  
import java.net.*;  t@B(+
 
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public class SiteFileFetch extends Thread { 8b&uU [  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ^gR+S  
long[] nStartPos; //开始位置 ]qktj=p  
long[] nEndPos; //结束位置 l\Ftr_Dk  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 {BV4h%P]:  
long nFileLength; //文件长度 XB\zkf_}Xc  
boolean bFirst = true; //是否第一次取文件 6Z! y  
boolean bStop = false; //停止标志 d/
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V}  
File tmpFile; //文件下载的临时信息 p+w8$8)  
DataOutputStream output; //输出到文件的输出流 z@h~Vb&I  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） %|IUqjg  
public SiteFileFetch(SiteInfoBean bean) throws IOException X;GfPw.m  
{
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siteInfoBean = bean; :,UN8L "  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); d,F5:w&  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); n^9  ?~  
if(tmpFile.exists ()) )|]dmQ-  
{ Vz:_mKA  
bFirst = false; tk?UX7F  
read_nPos(); >)#c\{c  
} S*t%RZ~a  
else h=+$>_&:  
{ ;=;JfNnbm  
nStartPos = new long[bean.getNSplitter()]; By((,QpB  
nEndPos = new long[bean.getNSplitter()];
q-AN[_@  
} *|RS*ABte  

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} uofLhy!  
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public void run() h4`9Cfrq,  
{ ARB7>"
 
//获得文件长度 v 81rfB5  
//分割文件 ~"dhu]^  
//实例FileSplitterFetch  ?J&)W,~  
//启动FileSplitterFetch线程 RQ' H!(K  
//等待子线程返回 {d!Y3+I%G  
try{ IgX4.]W5  
if(bFirst) 5K.+CO<  
{ Z9 w:&oa@  
nFileLength = getFileSize(); 

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if(nFileLength == -1) b1^cD6sT+  
{ C1B'#F9EO  
System.err.println("File Length is not known!"); j%tEZ"H  
} JF9Hfs/jS  
else if(nFileLength == -2) []p"3i  
{ a6nlt?1?D  
System.err.println("File is not access!"); 5Pke8K  
} rla:<6tt  
else XAD3Z?  
{ la, h  
for(int i=0;i<nStartPos.length;i++) @$U 
e$  
{ vDE |sT  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); P
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} %e=!nRc  
for(int i=0;i<nEndPos.length-1;i++) T\sNtdF`:  
{ t4K56H.L?  
nEndPos = nStartPos[i+1]; C0m\SNR  
} bkv/I{C>?  
nEndPos[nEndPos.length-1] = nFileLength; \ TL82H@D  
} .Ff_s  
} ZBM!MSf:  
->oz#   
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//启动子线程 e}"wL g]  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; J r*"V`  
for(int i=0;i<nStartPos.length;i++) A7Y_HIo  
{ P. V\ov7m2  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), .6T4z7I  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), jD9lz-Y@  
nStartPos,nEndPos,i); uxDLDA$;  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); a$}6:E  
fileSplitterFetch.start(); "tR}j,=S:D  
} X;EJ&g/  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), |]ucHV  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); )f*Iomp]@  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", h~UJCnzS  
nEndPos = " + nFileLength); u0]q`u/T  
// fileSplitterFetch[nPos.length-1].start(); =cp;Q,t'9L  
#7W.s!#}Dd  
Y5%;p33uFG  
//等待子线程结束 }$aNOf%:  
//int count = 0; A*0*sZ0  
//是否结束while循环 p24.bLr  
boolean breakWhile = false; r{ @
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(%DRt4u<H  
=K'L|QKF  
while(!bStop) O),
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{ vLn> 4SK  
write_nPos(); >q9{  
Utility.sleep(500); 0k1MKzi Q  
breakWhile = true; z,+m[x=/N  
r)
B3es&&  
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for(int i=0;i<nStartPos.length;i++) *l!5QG UoK  
{ 8=4^Lm  
if(!fileSplitterFetch.bDownOver) yq6LH  
{ ETelbj;0  
breakWhile = false; Oz>io\P94  
break; </ZHa:=7  
} 9dYOH)f  
} q/'MS[C  
if(breakWhile) AM/lbMr  
break; -$R5  
4  
cx:jUsb6  
//count++; rWe 8D/oc  
//if(count>4) 9::YR;NY  
// siteStop(); VjTAN=  
} *vs~SzF$  
#pa\2d|  
k2
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System.err.println("文件下载结束！"); t>oM%/H  
} 0UjyMEiK  
catch(Exception e){e.printStackTrace ();} 9|a)sb7/  
} $4h04_"  
me$$he  
8Mb$+^zU  
//获得文件长度 M6x;BjrV  
public long getFileSize() (WMLNv  
{ 4#@0T"T~M  
int nFileLength = -1; ?>TbTfmR  
try{ Gx|Dql  
URL url = new URL(siteInfoBean.getSSiteURL()); SyB-iQ
n  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ._(z~3s  
httpConnection.setRequestProperty("User-Agent","NetFox"); 3G(skphE  
>I:9'"`  
Esa6hU#  
int responseCode=httpConnection.getResponseCode(); Tvrc%L(]  
if(responseCode>=400) P.1Qc)m4  
{ d!!3"{'  
processErrorCode(responseCode); +1f{_v  
return -2; //-2 represent access is error f>4+,@G  
} ds')PIj  
b)y<.pS\  
|{!Ns+'  
String sHeader; oHRbAE^  
qKx59  
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for(int i=1;;i++) SmvwhX  
{ MHn&; A]  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 3]7ipwF2q  
//Utility.log(in.readLine()); #PPsRKj3c  
sHeader=httpConnection.getHeaderFieldKey(i); 98ayA$  
if(sHeader!=null) uTUa4^]*  
{ ]Y$&78u8t  
if(sHeader.equals("Content-Length")) C}bPv+t  
{ {{GHzW  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); LVWxd}0  
break; y
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} h!~|6nj  
} *<;&>w8  
else =mAGD*NKu  
break; s'2y%E#  
} &U854  
} -MsuBf  
catch(IOException e){e.printStackTrace ();} 7TR'zW2W  
catch(Exception e){e.printStackTrace ();} ZS|Z98  
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Utility.log(nFileLength); ap{{(y&R  
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return nFileLength; w7Pe  
} _i#@t7  
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//保存下载信息（文件指针位置） <"{+  
private void write_nPos() 5auL<Pq  
{ }]Qmt5'NI  
try{ >DkN+S  
output = new DataOutputStream(new FileOutputStream(tmpFile)); bmSpbX\  
output.writeInt(nStartPos.length); <w%Yq?^  
for(int i=0;i<nStartPos.length;i++) >n#g9vK  
{ FC~|&  
// output.writeLong(nPos); *%z<P~}  
output.writeLong(fileSplitterFetch.nStartPos); 2>`m<&y  
output.writeLong(fileSplitterFetch.nEndPos); ^glbxbhI4  
} 1h&)I%`?  
output.close(); )moo?Q  
} Py}!C@e  
catch(IOException e){e.printStackTrace ();} \qRjXadj  
catch(Exception e){e.printStackTrace ();} nqUH6(  
} B/:>{2cm  
0 [*nAo  
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//读取保存的下载信息（文件指针位置） Z={UM/6w  
private void read_nPos() OME!W w  
{ mJ7`.  
try{ /0X0#+kn  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); |~Htj4K/  
int nCount = input.readInt(); LAOdH/*:  
nStartPos = new long[nCount]; LZ3rr-  
nEndPos = new long[nCount]; MM/BJ  
for(int i=0;i<nStartPos.length;i++) /5a$@%  
{ U+I3P  
nStartPos = input.readLong(); cob9hj#&7  
nEndPos = input.readLong(); K[`4vsE  
} {^2({A#&  
input.close(); 4UkP:Vz:  
} zDKLo 3:  
catch(IOException e){e.printStackTrace ();} )^V5*#69D  
catch(Exception e){e.printStackTrace ();} VGkW3Nt0  
} Xd90n>4S  
>Lo6='G  
7r:nMPX  
private void processErrorCode(int nErrorCode) 6:8EZ'y  
{ }UJdE#4  
System.err.println("Error Code : " + nErrorCode); }7f 1(#{7  
} ~`tJvUo0  
)1X' W  
weTK#O0@v  
//停止文件下载 z{7,.S u  
public void siteStop() <VauJB*R  
{ #S/pYP`7  
bStop = true; p
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for(int i=0;i<nStartPos.length;i++) >'BU*  
fileSplitterFetch.splitterStop(); sPZV>Q:zY  
mmh nw(/  
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} !nZI? z;  
} a3DoLq"/  
//负责部分文件的抓取 bw<~R2[  
**FileSplitterFetch.java GN}9$:  
*/ vV\/pu8  
package NetFox; UU;Ysj  
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import java.io.*; ?eYchVq  
import java.net.*; #!K~_DL  
jn5=N[hd  
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public class FileSplitterFetch extends Thread { 2J>A;x_?  
n57c^/A*  
Hzk1LKsT#  
String sURL; //File URL n?7h
p%}  
long nStartPos; //File Snippet Start Position Yg]FF`{p=  
long nEndPos; //File Snippet End Position ;$k?&nhY  
int nThreadID; //Thread's ID HfZ (U5~  
boolean bDownOver = false; //Downing is over J~nJpUyP*  
boolean bStop = false; //Stop identical *$*nY [/5  
FileAccessI fileAccessI = null; //File Access interface iq[2H$  
#lLn='
4  
4Tbi%vF{  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException q=j/s4~  
{ @et3}-c  
this.sURL = sURL; -jklH/gF\%  
this.nStartPos = nStart; :&\E\9  
this.nEndPos = nEnd; `tUeT[  
nThreadID = id; T`(;;%  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 B7x"ef  
} EeF n{_  
&Pn%zfmMN  
Bm2}\KOI  
public void run() xu\/]f)  
{ ivDG3>"JG  
while(nStartPos < nEndPos && !bStop) 4G68WBT  
{ 2#Q"@  
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8B% O%*5`  
try{ k(w9vt0?  
URL url = new URL(sURL); RvgAI`T7$  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); q>Ar.5&M_  
httpConnection.setRequestProperty("User-Agent","NetFox"); `G:qtHn"Q<  
String sProperty = "bytes="+nStartPos+"-"; ?_<UOb*  
httpConnection.setRequestProperty("RANGE",sProperty); X/?h!
Y}  
Utility.log(sProperty); da
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]pucv!  
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InputStream input = httpConnection.getInputStream(); FC/>L  
//logResponseHead(httpConnection); "KQ\F0/  
dBi3ZCAF  
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byte[] b = new byte[1024]; CUTEp/+  
int nRead; SgQmYaa&  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) LI5cUCl  
{ ;74DT  
nStartPos += fileAccessI.write(b,0,nRead); d$G%F$BTs  
//if(nThreadID == 1) XDv7#Tv_wv  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); O(WMTa'%  
} =kZwB*7  
z2EI"'4\9  
c]/O^/  
Utility.log("Thread " + nThreadID + " is over!"); tMs|UC  
bDownOver = true; Y9c9/_CSj  
//nPos = fileAccessI.write (b,0,nRead); IWbp^l+!t  
} \T#(rt\j  
catch(Exception e){e.printStackTrace ();} nms<6kfzL  
} 2 3XAkpzp$  
} B?zS_Ue  
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GE|^ryh  
//打印回应的头信息 2%No>w}/2  
public void logResponseHead(HttpURLConnection con) ]nr BmKB  
{ t$kf'An}/  
for(int i=1;;i++) xhoLQD  
{ H2tpP~!G  
String header=con.getHeaderFieldKey(i); oXZ@*   
if(header!=null) 5)
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//responseHeaders.put(header,httpConnection.getHeaderField(header)); H1c|b!C  
Utility.log(header+" : "+con.getHeaderField(header)); aDJjVD  
else <`VJU2  
break; G^eFS;  
} ThiPT|5u  
} 9p0HFri[  
bD^ob.c.A  
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public void splitterStop() AK\g-]8  
{ 07WIa@Q  
bStop = true; sNan"  
} sN \}Q#:8  
nQ(:7PFa'  
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} 0 6v5/Xf  
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whp\*]8  
/* U\!LZ?gC  
**FileAccess.java 22(]x}`  
*//文件访问(定位，写) ~a0}  
package NetFox; d'@H@  
import java.io.*; 8 $*cfOC  
TKs@?Q,J  
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public class FileAccessI implements Serializable{ 5O;oo@A:[  
UC2OYZb  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 KcyM2hE7  
RandomAccessFile oSavedFile; u$`x]K=Zsm  
long nPos; Mm[1Z;H  
|\L,r}1N  
w"Y55EURB  
public FileAccessI() throws IOException zyQEz#O  
{ [g 68O*  
this("",0); K#pt8Q  
} %!/liS  
#i#.tc  
$ax%K?MBD  
public FileAccessI(String sName,long nPos) throws IOException hI#M {cz  
{ 5^qp&  
oSavedFile = new RandomAccessFile(sName,"rw"); ^ cd5Zl  
this.nPos = nPos; \\pyu]z  
oSavedFile.seek(nPos); IHX#BY>  
} MM)/B>cQt  
ykl=KR  
n'(n4qH2#s  
public synchronized int write(byte[] b,int nStart,int nLen) )ZT0zIG  
{ @T=HcUP)  
int n = -1; uN^qfJ'@ >  
try{ *[/Xhx"  
oSavedFile.write(b,nStart,nLen); ?ut juMdl  
n = nLen; .&!{8jBX  
} vM;dPE7  
catch(IOException e) 6L% R@r
 
{ S{|)9EKw  
e.printStackTrace (); -`1L[-<d=/  
} BGYm]b\j[  
\}Kp=8@nE  
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return n; +P;D}1B#I?  
} 7^e}|l  
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} &WV 9%fI  
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I }I/dh  
/* #AnSjl  
**SiteInfoBean.java >$9yQ9&|  
*/ B{i;+[ase  
package NetFox; uWT&`m_(2  
49kia!FR  
':>*=&  
public class SiteInfoBean { J]YN2{(x  
PSw+E';  
<Q~7a hF  
private String sSiteURL; //Site's URL xa^HU
~  
private String sFilePath; //Saved File's Path %QZ!Tb  
private String sFileName; //Saved File's Name 1VsEic  
private int nSplitter; //Count of Splited Downloading File xR%a
yT.  
fmN)~-DV9`  
H%%nB  
public SiteInfoBean() 0cU^ue%  
{//nSplitter的缺省值为5 _NW OSt  
//default value of nSplitter is 5 cCCplL  
this("","","",5); UR=s{nFd  
} 'GoeVq  
*N+aZV}`Z  
q%&7J<  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) _cs9
R%  
{ \r9%;?f  
sSiteURL= sURL; QQ8W;x  
sFilePath = sPath; #IwB  
sFileName = sName; /Day5\Q#  
this.nSplitter = nSpiltter; U2?gODh'  
VO6y9X"  
/pN2
Jst  
} Wm&f+{LO+K  
Ox'.sq4  
P!ICno6[e  
public String getSSiteURL() . +?lID  
{ ;
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return sSiteURL; PTZ1oD  
} o/ 5Fg>d  
]V("^.~$+C  
RN|..zml  
public void setSSiteURL(String value) VMXXBa&  
{ pa73`Ca]  
sSiteURL = value; 1uQ
f}  
} H)+kN'J  
m%\[1|N  
JH;DVPX9z  
public String getSFilePath() <\mc|p"  
{ [SvwJIJJ  
return sFilePath; ]}l!L;  
} .e+UgCwi  
jU~%5R  
KYW1<Wcp  
public void setSFilePath(String value) (%!R  
{ m(P)oqwM  
sFilePath = value; c!T{|'?  
} sn#h=,*4`  
L,/i%-J3c  
#|i{#~gxM  
public String getSFileName() 4BtdN-T}b  
{ ]~ M -KT  
return sFileName; L?(rv.lb  
}
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mjHY-lK  
AUV$ S2  
public void setSFileName(String value) ^w\uOd`  
{ d(Ou\7  
sFileName = value; UQ~rVUo.c  
} =h;!#ZC  
F#wa)XH
 
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public int getNSplitter() b1o(CG(}*  
{ !Esiq<Yh  
return nSplitter; dY.uOafr  
} KJfyh=AD(  
Dw3! ibg  
Oc`fQqYy  
public void setNSplitter(int nCount) BE)l77=/  
{ ^*Fkt(ida  
nSplitter = nCount; M3kE91  
} 20)Il:x  
} #!Fs
[A5%  
7:%K-LeaQu  
A-$BB=Ot  
/* i=+6R  
**Utility.java I:"`|eHxv  
*/ <H/H@xQ8G  
package NetFox; 5?MvO]_  
<|iU+.j\  
')V5hKb^  
public class Utility { +pm8;&  
F o6U"  
vGw}e&YI  
public Utility() OHo0W)XUU  
{ s qKkTG3  
{IvCe0`  
R[;Z<K\Nn?  
} 9g"H9)EZ^  
]Ox.6BKjDP  
//线程睡眠 NM Ajt>t  
public static void sleep(int nSecond) zOw]P6Gk  
{ =qvU9p2o  
try{ ;4IP7$3G  
Thread.sleep(nSecond); cD6o8v4]]  
} 6dUP's_  
catch(Exception e) H<yec"  
{ JGe;$5|q8  
e.printStackTrace (); 2<|5zF  
} m}(DJ?qP  
} &Te:l-x  
Y# #J  
//日志 ~Zm(p*\T  
public static void log(String sMsg) 4`F*] Ft  
{ <k!G%R<9  
System.err.println(sMsg); _p.{|7  
} 4E)[<%  
$;1~JOZh  
9[*kpMC  
public static void log(int sMsg) \=<.0K A~  
{ 6>Y}2fT}o3  
System.err.println(sMsg); z6qC6Ck|  
} &.,OvVAo  
} W8^gPW*c5  
g:g>;"B O  
"$&F]0  
/* "<WSEs  
**TestMethod.java 2h!3[{M\  
*/ ?H`LrL/k  
package NetFox; T9^i#8-^  
N\?iU8w=  
Y>+D\|%
Q  
public class TestMethod { c#DTL/8"DO  
ln.~>FO  
4\?B,!  
public TestMethod() o%.cQo=v*
 
{ ///xx/weblogic60b2_win.exe a lR}|ez  
try{ U#}.r<  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); e_TM#J(3  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); /%7eo?@,  
SiteFileFetch fileFetch = new SiteFileFetch(bean); m[pzu2R  
fileFetch.start(); aZRgd^4  
} ol\IT9Zb~  
catch(Exception e){e.printStackTrace ();} jDoWSYu4tY  
u@HP@>V  
oKac~}_KL  
} ^cNP?7g7  
`@&qf}`  
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public static void main(String[] args) @&+ 1b=  
{ <3bh-
)  
new TestMethod(); ~"N]%Cu  
} 3,
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} saV`-#  
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