http断点续传简单实现（java)

/* [1LlzCAFBw  
**SiteFileFetch.java >l0y ss)I  
*/ 17 k9h?s*  
package NetFox; vhEqHjR:  
import java.io.*; ?g6xy[  
import java.net.*; 5~pQ$-  
1 +0-VRl  
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public class SiteFileFetch extends Thread { ef Moi'v  
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**D3.-0u&  
SiteInfoBean siteInfoBean = null; //文件信息Bean Az`c? W%  
long[] nStartPos; //开始位置 UdiogXZ  
long[] nEndPos; //结束位置 M2$.Yom[  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 \~(scz$  
long nFileLength; //文件长度 mSg{0_:  
boolean bFirst = true; //是否第一次取文件 "CX@a"
 
boolean bStop = false; //停止标志 uZg[PS=@!X  
File tmpFile; //文件下载的临时信息 ~l^Q~W-+  
DataOutputStream output; //输出到文件的输出流 I*SrKZb  
:rBPgrt  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） U5iyvU=UG  
public SiteFileFetch(SiteInfoBean bean) throws IOException C8xxR~mq  
{ j& H4L  
siteInfoBean = bean; Cwh*AKq(  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); or8`.hEHI  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); *%nV<}e^_=  
if(tmpFile.exists ()) xpO'.xEs  
{ =(3Yj[>st  
bFirst = false; PXx:JZsju  
read_nPos(); +n)_\@aQ  
} !jySID?q  
else JZo18^aD"'  
{ [J{M'+a  
nStartPos = new long[bean.getNSplitter()]; x(tf0[g  
nEndPos = new long[bean.getNSplitter()]; Hdn%r<
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} ev{;}2~V  
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} |*T`3@R;3  
\U?$r[P  
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public void run() Nuebxd
 
{ U
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//获得文件长度 , S }  
//分割文件 [Zpx :r}  
//实例FileSplitterFetch ~0 PR>QJ  
//启动FileSplitterFetch线程 4ZX6=-u^  
//等待子线程返回 _=\J:r|Y:  
try{  EL$"/ptE  
if(bFirst) \Zgc [F  
{ %$*WdK#  
nFileLength = getFileSize(); 2}BQ=%E!'  
if(nFileLength == -1) rP7[{'%r  
{ }#<mK3MBe  
System.err.println("File Length is not known!"); nj(\+l5  
} C5F=J8pY  
else if(nFileLength == -2) )&") J}@  
{ -Gyj]v5y`c  
System.err.println("File is not access!"); Cd7imj  
} YjR`}rdwo  
else {tDH !sX  
{ \Qgc7ev  
for(int i=0;i<nStartPos.length;i++) ;k=&ZV  
{ c{,VU.5/  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); J
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} v]?zG&Jh  
for(int i=0;i<nEndPos.length-1;i++) y!kU0  
{ %`# HGji)  
nEndPos = nStartPos[i+1]; ]Uu:t  
} 9sI&&Jg  
nEndPos[nEndPos.length-1] = nFileLength; i[#XYX'\  
} |b+ZKRW  
} !!\x]
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}|j\QjH  
_-R&A@  
//启动子线程 Ifu[L&U  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; L>>RboR}  
for(int i=0;i<nStartPos.length;i++) Tp[-,3L  
{ {@7x
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fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), /)-OK7x  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), y(fJ{k   
nStartPos,nEndPos,i); G(fS__z  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); b3M`vJ+{  
fileSplitterFetch.start(); ?nCo?A  
} w2(pgWed  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ^Mmsja5K  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); a`*Dq"9pV  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Aw)I:d7F  
nEndPos = " + nFileLength); ?heg_~P  
// fileSplitterFetch[nPos.length-1].start(); !XqU'xxC  
2e<u/M21>  
B'D\l\w  
//等待子线程结束 Gv+$7{  
//int count = 0; ;xQNa}"V  
//是否结束while循环 >>b <)?3Rv  
boolean breakWhile = false; c.eUlr_{  
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uz /Wbc>y  
while(!bStop) .dO8I/lhV  
{ NW4tQ;ad  
write_nPos(); t[4V1:  
Utility.sleep(500); $l=&  
breakWhile = true; R8%%EEB  
Rh,a4n?W  
'o]kOp@q  
for(int i=0;i<nStartPos.length;i++) @9e}kiW  
{ ak"W/"2:  
if(!fileSplitterFetch.bDownOver) _C
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{ !Pc&Sg  
breakWhile = false; Wi+}qO  
break; F^Y%Q(Dd7w  
} @QO^3%b8  
} hQ@E2Xsv  
if(breakWhile) .gclE~h.  
break; gski:C   
h3rVa6cxM  
QF4)@ r{2x  
//count++; 9q]n&5  
//if(count>4) k4-S:kVo  
// siteStop(); ;W?mQUo:P8  
} )&s9QBo{b  
I&wJK'GM`  
2)MX<prH  
System.err.println("文件下载结束！"); QX+Xi<YE-  
} W QqOXF  
catch(Exception e){e.printStackTrace ();} &hcD/*_Z  
} ;Qi0j<dXd  
zhgvqg-  
 \OW.?1d  
//获得文件长度 {WvYb,
  
public long getFileSize() _
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{ hlBMRx49  
int nFileLength = -1; }Y!v"DO#Q*  
try{ .(%]RSBY  
URL url = new URL(siteInfoBean.getSSiteURL()); |
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); D%*Ryg  
httpConnection.setRequestProperty("User-Agent","NetFox"); PS3jCT  
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O<P(
UT"  
int responseCode=httpConnection.getResponseCode(); VVw5)O1'  
if(responseCode>=400) Y3JIDT^  
{ !<vy!pXg  
processErrorCode(responseCode); /d*[za'0  
return -2; //-2 represent access is error L_Xbca=  
} nIWY<Z"  
iyv
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6&;h+;h  
String sHeader; &Lbh?C  
*|as-!${k  
8/<+p? 3p>  
for(int i=1;;i++) `Jj q5:\&  
{ ,*.qa0E#W  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); &,tj.?NCn  
//Utility.log(in.readLine()); 6>gm!6`  
sHeader=httpConnection.getHeaderFieldKey(i); 3Dx@rW\  
if(sHeader!=null) ( TJGJY  
{ 9Cs/B*3)b  
if(sHeader.equals("Content-Length")) wv  
{ 1T}jK^"  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); e^k)756  
break; |pZ:5ta#  
} CI1K:K AM  
} _`lPLBr6  
else +xS<^;   
break; ~NTKWRaR  
} R0urt  
} Py\/p Fvg  
catch(IOException e){e.printStackTrace ();} =9;b|Y"aQ  
catch(Exception e){e.printStackTrace ();} >VppM  `  
Fh4Exl@6  
`Y3\R#  
Utility.log(nFileLength); O4cBn{Dq9  
&ZL4/e  
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return nFileLength; :W#?U yo  
} D `av9I  
{s
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b%].D(qBy  
//保存下载信息（文件指针位置） 7ufTmz#j<  
private void write_nPos() `SA1V),~  
{ 3X#Cep20a  
try{ =&^tfD  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 7AF6aog  
output.writeInt(nStartPos.length); %<|cWYM="z  
for(int i=0;i<nStartPos.length;i++) s_3a#I  
{ !p Q*m`Xo  
// output.writeLong(nPos); 9&zQ5L>  
output.writeLong(fileSplitterFetch.nStartPos); KB{IWu  
output.writeLong(fileSplitterFetch.nEndPos); :<v@xOzxx  
} YIF|8b\  
output.close(); G!Yt.M0  
} M5
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catch(IOException e){e.printStackTrace ();} o$#q/L  
catch(Exception e){e.printStackTrace ();} t$b5,"G1  
} b3ys
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nG$+9}\UlP  
,/"0tP&_;  
//读取保存的下载信息（文件指针位置） <Ira~N  
private void read_nPos() Z&n#*rQ7[  
{ to?={@$]  
try{ 3bT?4  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); r::0\{{r"p  
int nCount = input.readInt(); I%{ 1K+V/  
nStartPos = new long[nCount]; LfJMSscfv  
nEndPos = new long[nCount]; XePGOw))O  
for(int i=0;i<nStartPos.length;i++) eH~T PH  
{ o7^0Lo5Z?  
nStartPos = input.readLong(); </b_Rar  
nEndPos = input.readLong(); %pLqX61t=  
} z'*{V\  
input.close(); (+}44Ldt  
} bc;?O`I<  
catch(IOException e){e.printStackTrace ();} o*3\xg  
catch(Exception e){e.printStackTrace ();} -"I9`  
} 3_>=Cv}  
X<H{  
gYloY=.Z$'  
private void processErrorCode(int nErrorCode) gX|\O']6  
{ >vXS6`;  
System.err.println("Error Code : " + nErrorCode); [
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} 6Ilj7m*  
4wWfaL5"  
u4'B  
//停止文件下载 4>/i,_&K K  
public void siteStop() xZ(d*/6E  
{ 53?Ati\Y)  
bStop = true; mC3:P5/c  
for(int i=0;i<nStartPos.length;i++) z/nW;ow  
fileSplitterFetch.splitterStop(); gGx<k3W^  
ND/oKM+?  
h gu\~}kD  
} wYDdy gS  
} Lt i2KY}/%  
//负责部分文件的抓取 {Es1
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**FileSplitterFetch.java 9v1Snr  
*/ {;Oj  
package NetFox; 9m<%+S5&  
U;*O7K=P  
ce*?crOV  
import java.io.*; s#(7D3Pr#  
import java.net.*; L* ScSxw  
p.H`lbVY  
IJC]Al,df  
public class FileSplitterFetch extends Thread { etQS&YzC  
5H,(\Xd  
i^8w0H<-@v  
String sURL; //File URL /B|"<`-H  
long nStartPos; //File Snippet Start Position CAmIwAx6;  
long nEndPos; //File Snippet End Position ff=RKKnN  
int nThreadID; //Thread's ID k5*Z@a  
boolean bDownOver = false; //Downing is over A|GsbRuy  
boolean bStop = false; //Stop identical 7%G&=8tq  
FileAccessI fileAccessI = null; //File Access interface _#uRKy<`N  
jUDE)~h  
%cJdVDW`L  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException q29d=  
{ J4s`U/F  
this.sURL = sURL; _Fe=:q  
this.nStartPos = nStart; Qz"//=hC|H  
this.nEndPos = nEnd; U ,!S1EiBs  
nThreadID = id; 1bHQB$%z  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 {:KPEN  
} x![G'I  
mo,"3YW  
a54S,}|  
public void run() na 0Zb  
{ mX, @yCI  
while(nStartPos < nEndPos && !bStop) er2;1TW3E  
{ EfkBo5@Qi  
P@x@5
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{
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try{ %d<UMbS^  
URL url = new URL(sURL); LR'~:46#u  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); *}_i[6_\E  
httpConnection.setRequestProperty("User-Agent","NetFox"); WI.+9$1:P  
String sProperty = "bytes="+nStartPos+"-"; %IDl+_j  
httpConnection.setRequestProperty("RANGE",sProperty); (`u+(M!^  
Utility.log(sProperty); .4[M-@4+]  
ylDfr){  
@}uo:b:Q  
InputStream input = httpConnection.getInputStream(); 44KWS~  
//logResponseHead(httpConnection); Cv/3-&5S  
Ns#L9T#  
!3o/c w9  
byte[] b = new byte[1024]; C4t~
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int nRead; EW3--33s  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) /Xv@g$  
{ y)TBg8Q  
nStartPos += fileAccessI.write(b,0,nRead); Bo1 t}#7  
//if(nThreadID == 1) ,dFY]  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 2vddx<&  
} dj}P|v/;z  
)Y"t$Iw"  
#-{ljjMQI  
Utility.log("Thread " + nThreadID + " is over!"); G^SDB!/@J  
bDownOver = true; NE3/>5  
//nPos = fileAccessI.write (b,0,nRead); '#~Sb8   
} z6h/C{  
catch(Exception e){e.printStackTrace ();} ]BTISaL-R  
} u'gsIuRJ  
} Q5IN1 ^=HF  
QUF1_Sa  
" LhXR  
//打印回应的头信息 AJ6O>Euq  
public void logResponseHead(HttpURLConnection con) @V+KL>Qw  
{ Q
8h=2YL  
for(int i=1;;i++) 9WHarv2@  
{ ]eX(K5 A  
String header=con.getHeaderFieldKey(i); rP/W,! 7:K  
if(header!=null) &ha<pj~  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); T(k:\z/  
Utility.log(header+" : "+con.getHeaderField(header)); L Z3=K`gj  
else >feeVk  
break; 8^R~qp
g%  
} `_"?$ v2F  
} C\|HN=2eh  
2d<`dQY{l3  
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public void splitterStop() D2io3Lo$ov  
{ }/g1  
bStop = true; v[a4d&P  
} ZB5NTNf>  
u!b0<E  
3ZvQUH/{W  
} v{8r46Y~Z)  
/)rv Ndn  
#jg3Ku;Y  
/* -cUw}  
**FileAccess.java t1G2A`  
*//文件访问(定位，写) #rp)Gc  
package NetFox; 2#'"<n,G
 
import java.io.*; y@Td]6|f  
6']WOM#  
NIC.c3  
public class FileAccessI implements Serializable{ 6*I=% H|  
t3!~=U  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ~$7YEs)  
RandomAccessFile oSavedFile; 0f;|0siTAm  
long nPos; I#W J";kqB  
VY0-18 o  
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public FileAccessI() throws IOException '47E8PIJ|  
{ ffa
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this("",0); j'UWgwB  
} 7qdB  
}c#W"y5l_  
"2T* w~V&y  
public FileAccessI(String sName,long nPos) throws IOException 0 Gq<APtr  
{ &*~_ "WyU  
oSavedFile = new RandomAccessFile(sName,"rw"); ^n\g,  
this.nPos = nPos; #Q|ACNpYM  
oSavedFile.seek(nPos); <,9rXjeRl  
} VxU{ZD~<Z"  
,~NJ}4wP  
.;&4'ga4  
public synchronized int write(byte[] b,int nStart,int nLen) ,@Elw>^  
{ !ed0  
int n = -1; <_4'So>  
try{ _n4C~  
oSavedFile.write(b,nStart,nLen); 6O'Y@9#  
n = nLen; t<+
gyAW  
} qi8~bQ{rH  
catch(IOException e)  f^[m~  
{ {65_k  
e.printStackTrace (); t\\<+^[%  
} Qr~yHFc1y  
^K^rl9  
A.<M*[{q  
return n; >a: 6umY  
} "}uV=y  
Ul|htB<1:  
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} t5S!j2E  
@EH@_EwYV  
85+w\KuEY  
/* ,6wGdaMR  
**SiteInfoBean.java vGp`P  
*/ PxJvE*6^H  
package NetFox; 1c$ce+n~  
AHLXmQl  
Lx3`.F\m
G  
public class SiteInfoBean { '8|joj>G=  
U2(mWQ[mO  
\%.&$z3wz  
private String sSiteURL; //Site's URL "GAKi}y">v  
private String sFilePath; //Saved File's Path .
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private String sFileName; //Saved File's Name ~Ecx>f4nX  
private int nSplitter; //Count of Splited Downloading File ?lIh&C8]X  
1xsB@D  
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public SiteInfoBean() E
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{//nSplitter的缺省值为5 &"X1w $  
//default value of nSplitter is 5 ES[]A&tf  
this("","","",5); S2$r 6T  
} (KT+7j0^  
=5g|7grQ:`  
tU>4?`)E  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) {z8wFL\  
{ ]?hlpL  
sSiteURL= sURL; !]P=v`B.  
sFilePath = sPath; Kj|\ALI':  
sFileName = sName; *YTv"  
this.nSplitter = nSpiltter; Qy) -gax:,  
~gOdK-SV*  
7:OF>**  
} QQUZneIDp  
2%j"E{J&  
QH6_nZY  
public String getSSiteURL() ,uS}wJAX  
{ !]#;
'  
return sSiteURL; E1|:t$>Ld  
} .c_qMTm"  
Q_|Lv&  
.vpx@_;]9  
public void setSSiteURL(String value) LLwC*)#  
{ iMp_1EXe  
sSiteURL = value;  C0j`H(  
} k i{8f  
}yM!o`90  
Z]^O=kX7k  
public String getSFilePath() %eE 6\f%g  
{ t` zPx#])  
return sFilePath; `w%Qs)2  
} a8Z{-=)  
WD#7Q&T(;  
ks<+gL{K|i  
public void setSFilePath(String value) ?/Z5%?6  
{ {7 nz:f  
sFilePath = value; R,W w/D  
} 1zY"Uxp  
0u ,nSvch  
hu-6V="^9  
public String getSFileName() h) W|~y@  
{ J|dj`Z?  
return sFileName; @86I|cY  
} H`8}w{ft&  
qjLFgsd  
Ert` ]s~  
public void setSFileName(String value) DgC;1U'  
{ W/<C$T4  
sFileName = value; ((]Sy,rdk  
} &+8cI^kp  
'V:ah38  
e>$E67h<~  
public int getNSplitter() FeuqqZ\=&  
{ <0H^2ekd  
return nSplitter; F2mW<REg{  
} 6
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etH]-S  
7.C~ OrGR  
public void setNSplitter(int nCount) -{S:sK.o  
{ EY[J;H_b  
nSplitter = nCount; q!}O+(kt  
} 66Xo3o  
} Ea?u5$>gY"  
i^&^eg'.5  

:<`po4/  
/* O `a4 ")R  
**Utility.java ^es/xt  
*/ TllIs&MCe  
package NetFox; O\)rp!i  
A\~tr   
T&kr IZw  
public class Utility { R]Pv=fn  
M`.v/UQn  
{~eVZVv  
public Utility() ;bes#|^F  
{ @ykM98K  
I0C$  
(Zv/(SE5%  
} )nA fT0()0  
Ct30EZ  
//线程睡眠 h$q=NTV  
public static void sleep(int nSecond) ~!TRR.  
{  #Up X  
try{ 5<L+T  
Thread.sleep(nSecond); <LA!L  
} TTzvH;S  
catch(Exception e) O{nM yB  
{ I]Jz[{~1  
e.printStackTrace (); D]$X@2A  
} ,.&y-?  
} jsnk*>j  
ayoqitXD?  
//日志 1A-ess\  
public static void log(String sMsg) R3gg{hQ  
{ 8iwqy0<  
System.err.println(sMsg); tJ!s/|u(  
} NU$?BiB?R  
UqaV9  
8!u8ZvbFG  
public static void log(int sMsg) mA>u6Rlc  
{ T_b$8GYfCY  
System.err.println(sMsg); Q{+N{/tF  
} z\?cazQ  
} WEFvJ0]  
uGH>|V9'c  
b)Dzau  
/* &Ew{{t;"  
**TestMethod.java D\i8WU  
*/ DZ~qk+,I  
package NetFox; V50FX}i  
e|jmOYWG  
V?"SrXN>  
public class TestMethod { {%Q&CQG_  
;UG]ckV-  
x*2'I  
public TestMethod() +Q6}kbDI  
{ ///xx/weblogic60b2_win.exe 1lLL9l{UVw  
try{ _0(Bx?[h  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); XKt">W  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); -<Zs7(  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ]Uee!-dZ  
fileFetch.start(); 'CSIC8M<j  
} N++jI(  
catch(Exception e){e.printStackTrace ();} WGeTL`}dh  
&?mJL0fy  
bhWH  
} {@8TGHKv  
A$]&j5nh|  
,Bg)p_B  
public static void main(String[] args) u!VAAX  
{ WfDpeXdO  
new TestMethod(); N-4k 9l1  
} 8V$:th('  
} U*sQYt<?g  
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