http断点续传简单实现（java)

/* =r?#,'a  
**SiteFileFetch.java
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*/ KV1/!r+
*  
package NetFox; b@p3iq:  
import java.io.*; `fL81)!jI#  
import java.net.*; R=/^5DZ}  
=&9x}4`;%  
|_ChK6Q?v  
public class SiteFileFetch extends Thread { =~|:93]k  
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SiteInfoBean siteInfoBean = null; //文件信息Bean *F_ dP
  
long[] nStartPos; //开始位置 #z.QBG@  
long[] nEndPos; //结束位置 krt8yAkG  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 y
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long nFileLength; //文件长度 {(00,6M)i  
boolean bFirst = true; //是否第一次取文件 h3udS{9'8  
boolean bStop = false; //停止标志 Lt<KRs  
File tmpFile; //文件下载的临时信息 XFS"~{  
DataOutputStream output; //输出到文件的输出流 <E&[sQ|3  
<0%X:q<  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） (hb\1wZ  
public SiteFileFetch(SiteInfoBean bean) throws IOException >U%:Nfo3  
{ da,;IE{1u  
siteInfoBean = bean; =o<iBbK#|  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); zfexaf!  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); AhNy+p{  
if(tmpFile.exists ()) C=y[WsT  
{ 'K8emt$d+  
bFirst = false; C{5^UCJkg  
read_nPos(); |1rKGDc  
} I7Uj<a=(q  
else K]bw1KK  
{ z}gfH|  
nStartPos = new long[bean.getNSplitter()]; m0$
4  
nEndPos = new long[bean.getNSplitter()]; 0/g 0=dW=  
} X6Y<pw`y  
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} XZ3)gYQi  
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public void run() }
}cS-p  
{ 1vmK
d  
//获得文件长度 s?}m~Pl  
//分割文件 sz?/4tY
 
//实例FileSplitterFetch ~?BN4ptc  
//启动FileSplitterFetch线程 h^`!kp  
//等待子线程返回 R, J(]ew  
try{ 4/Wqeq,E8  
if(bFirst) W/?\8AE
 
{ L'KgB=5K&i  
nFileLength = getFileSize(); CnvM>]  
if(nFileLength == -1) @71n{9  
{ L{i,.aE/nO  
System.err.println("File Length is not known!"); [=otgVteN"  
} *pOdM0AE  
else if(nFileLength == -2) .=u8`,sO  
{ 'u)zQAaw.  
System.err.println("File is not access!"); kpQXnDm2  
} !K0:0:  
else E7c!KJ2  
{ SFaG`T=  
for(int i=0;i<nStartPos.length;i++) GQR|t?:t  
{ ~Wox"h}(  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); FFvF4]|L  
} QL{^  
for(int i=0;i<nEndPos.length-1;i++) BB)(#yoi  
{ 7YLG<G!v)]  
nEndPos = nStartPos[i+1]; KK|AXoBf  
}
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nEndPos[nEndPos.length-1] = nFileLength; "T?hIX/p_  
} tu%!j}3s  
} $ M8ZF(W  
qa!3lb_'M  
cc %m0p  
//启动子线程 `62iW3y  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ~|>q)4is6a  
for(int i=0;i<nStartPos.length;i++) ":G\  
{ 'Drz6K_KrP  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), kM>Bk\  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), LKx<hl$O  
nStartPos,nEndPos,i); SD=kpf;  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Js706  
fileSplitterFetch.start(); o/6'g)r*  
} hh$V[/iK  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), i!U,qV1  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); W-ctx"9DS  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ux 7^PTgcO  
nEndPos = " + nFileLength); Te:
4z@?  
// fileSplitterFetch[nPos.length-1].start(); ;hcOD4or  
uv}?8$<\  
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//等待子线程结束 }0%~x,  
//int count = 0;  oRbG6Vv/  
//是否结束while循环 ,{tK{XpS  
boolean breakWhile = false; `RriVYc<  
z
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while(!bStop) l^ Q-KUI  
{ o(w xu)  
write_nPos(); /Mg$t6vM  
Utility.sleep(500); a'U}.w}  
breakWhile = true; T/b%,!N)  
Z%t"~r0PS  
Jh)x_&R&Q  
for(int i=0;i<nStartPos.length;i++) e=yQFzQT)  
{ 82z\^a  
if(!fileSplitterFetch.bDownOver) &/}reE*  
{ p}r1@L s  
breakWhile = false; +wwb+aG6{  
break; 2yt)"DnFk  
} 0j--X?-  
} ^@"EI|fsP  
if(breakWhile) x?*)  
break; *nj={Ss&  
VPAi[<FzOG  
z3\
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//count++; Hfw*\=p  
//if(count>4) e{*-_j"I  
// siteStop(); #KOr-Yg|U  
} *G6Py,- !f  
.*3.47O  
}K8W%h
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System.err.println("文件下载结束！"); Wvg
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} `ecIy_O3P&  
catch(Exception e){e.printStackTrace ();} 2D"n#O`y  
} {[<o)k.A  
afOix"  
:nYnTo`  
//获得文件长度 ?$>#FKrt  
public long getFileSize() >3v j<v}m  
{ pel{
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int nFileLength = -1; sFvu@Wm'7W  
try{ I&jiH)  
URL url = new URL(siteInfoBean.getSSiteURL()); @`,~d{ziF  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); )U?O4| \P  
httpConnection.setRequestProperty("User-Agent","NetFox"); D (>,#F  
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V^  
int responseCode=httpConnection.getResponseCode(); !(-lY(x  
if(responseCode>=400) gYtv`O  
{ lhN2xg5x  
processErrorCode(responseCode); {Y\W&Edw%  
return -2; //-2 represent access is error H2plT  
} nNN~Z'bG  
V5ySOgzw,  
}r+(Z.BHM  
String sHeader; 7jZE(|G-  
b#17N2xkT  
u@"nVHgMJ  
for(int i=1;;i++) ;E!(W=]*F  
{ >l!#_a  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); O/|,rAE  
//Utility.log(in.readLine()); (pU@$H  
sHeader=httpConnection.getHeaderFieldKey(i); T@S\:P  
if(sHeader!=null) re$xeq\1P?  
{ $CXMeY{tOo  
if(sHeader.equals("Content-Length")) (iT?uMRz  
{ EINjI:/D  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); u
aX#nn?ws  
break; ^uDNArDmj5  
} OIqisQ7ZB  
} CXe2G5  
else C`++r>  
break; ['*{f(AI  
} I"4Lma  
} 3>+9Rru  
catch(IOException e){e.printStackTrace ();} r&MHww1i  
catch(Exception e){e.printStackTrace ();} Q7~9~  
w,,QXJe{Z_  
N 9.$--X}D  
Utility.log(nFileLength); vq.~8c1  
;?*`WB  
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return nFileLength; QO-R>  
} xYgG  
_`H2CXGg  
g}vOp3^  
//保存下载信息（文件指针位置） }:b6WN;c  
private void write_nPos() )}G?^rDH(  
{ v4pFts$J  
try{ 0Bo7EV  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ?tf/#5t}  
output.writeInt(nStartPos.length); ;j#(%U]Vp  
for(int i=0;i<nStartPos.length;i++) _0v+g1x  
{ w[WyT`6h!  
// output.writeLong(nPos); :cvZk|b%  
output.writeLong(fileSplitterFetch.nStartPos); w6-A-M6hD  
output.writeLong(fileSplitterFetch.nEndPos); z)Yk&;XC  
} qG=>eRR  
output.close(); ':mw(`  
} sy ]k  
catch(IOException e){e.printStackTrace ();} o9j*Yz  
catch(Exception e){e.printStackTrace ();} [\Ks+S  
} &yQilyU{V  
o:p6[SGd  
{N \ri{|  
//读取保存的下载信息（文件指针位置） 9(\eL9^  
private void read_nPos() `YK2hr  
{ j/oM^IY  
try{ &V.\Svm8]  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); .[@TC@W  
int nCount = input.readInt(); ({R-JkW:;  
nStartPos = new long[nCount]; 
l[MP|m#  
nEndPos = new long[nCount]; ~_!lx  
for(int i=0;i<nStartPos.length;i++) $,/;QP}  
{ QM"\;l??  
nStartPos = input.readLong(); d~G, *  
nEndPos = input.readLong(); Rr9K1io$)  
} (.CEEWj%{  
input.close(); gJ; *?Uq(  
} Ew&pwsQ  
catch(IOException e){e.printStackTrace ();} $,mljJSQv  
catch(Exception e){e.printStackTrace ();} efc<lSUR  
} ?)Psf/  
-w[j`}([P9  
C\Y%FTS:  
private void processErrorCode(int nErrorCode) h~!KNF*XW  
{ >nqDUGnEo>  
System.err.println("Error Code : " + nErrorCode); v>p UVM  
} &gP/<!#  
*an^ 0  
L,(H(GeX  
//停止文件下载 3U_-sMOB|  
public void siteStop() ,n}h_ct  
{ >q}Ns^ .'  
bStop = true; d4 Hpe>  
for(int i=0;i<nStartPos.length;i++) '=M4(h  
fileSplitterFetch.splitterStop(); rx
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+b9gP\Hke  
N=JZtf/i  
} -L.U4x  
} pG|+\k/B  
//负责部分文件的抓取 *2?-6  
**FileSplitterFetch.java y1oQ4|KSI  
*/ 
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package NetFox; EJ%Kr$51K  
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4 8}\  
import java.io.*; $N}nO:`t  
import java.net.*; Z4"SKsJT/>  
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public class FileSplitterFetch extends Thread { ( <Abw{BTm  
Dc2U+U(J  
75^U<Hz-3{  
String sURL; //File URL 9{A[n}  
long nStartPos; //File Snippet Start Position ^|P/D  
long nEndPos; //File Snippet End Position _3pME9
l  
int nThreadID; //Thread's ID l{2Y[&%  
boolean bDownOver = false; //Downing is over R
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boolean bStop = false; //Stop identical T[?toqkD>z  
FileAccessI fileAccessI = null; //File Access interface P2j"L#%  
<{z*6FM!'  
AjW5H*  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException y<h~jz#hkq  
{ -MCDX^>P  
this.sURL = sURL; dr54D  
this.nStartPos = nStart; K[.*8  
this.nEndPos = nEnd; o>#ue<Bc6  
nThreadID = id; Fm|h
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fileAccessI = new FileAccessI(sName,nStartPos);//定位 q JdC5z\[  
} VJ8"Q  
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public void run() dYEsSFB m  
{ MnQ4,+ji-  
while(nStartPos < nEndPos && !bStop) vi4lmkyh^  
{ -;i vBR  
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try{ 8B*XXFy\  
URL url = new URL(sURL); BDO]-y  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Im<i.a <`  
httpConnection.setRequestProperty("User-Agent","NetFox"); DJ!<:9FD  
String sProperty = "bytes="+nStartPos+"-"; fH>I/%  
httpConnection.setRequestProperty("RANGE",sProperty); &nRbI:R  
Utility.log(sProperty); qgk-[zW#  
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InputStream input = httpConnection.getInputStream(); c9 &LKJ6  
//logResponseHead(httpConnection); b:c$EPK  
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byte[] b = new byte[1024]; Jtv~
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int nRead; g]ct6-m  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) a%IJ8t+mn  
{ BM }{};p6  
nStartPos += fileAccessI.write(b,0,nRead); }OJ,<!v2pc  
//if(nThreadID == 1) 2`]`nTz,  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); G]$.bq[v  
} }(yX$ 3?`  
/_?y]Ly[r  
1p|h\H  
Utility.log("Thread " + nThreadID + " is over!"); (H_YYZ3ZX  
bDownOver = true; B=R9K3f  
//nPos = fileAccessI.write (b,0,nRead); -!ARVf *  
} x=7qC#+)  
catch(Exception e){e.printStackTrace ();} Wpdn^=dhL  
} 1B5]1&M  
} zG|#__=T  
d.)%C]W{  
e=).0S`*F  
//打印回应的头信息 Mqk[+n  
public void logResponseHead(HttpURLConnection con) dB=aq34l  
{ Y~fa=
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for(int i=1;;i++) ,t!K? Y  
{ in[yrqFb7t  
String header=con.getHeaderFieldKey(i); x3QQ`w-  
if(header!=null) bo]= *  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); "A>/m"c]*  
Utility.log(header+" : "+con.getHeaderField(header)); %"C%pA  
else Z2t r?]  
break; ]i@
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} kzb%=
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} ^=1:!'*3D  
7/UdE:~]*=  
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public void splitterStop() W3HTQGV  
{ U~}cib5W5  
bStop = true; #A@d;U%  
} FL/395 <:  
,5 ylrE  
Tg-HR8}X  
} g(b:^_Nep  
P
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Di^7@}kQS  
/* ~t,-y*=  
**FileAccess.java g3h:oQCS  
*//文件访问(定位，写) DH*=IzcJf  
package NetFox; vp_$Ft-R  
import java.io.*; R3<2Z0lqy  
(UGmbRf&  
/5s,< 0Kz  
public class FileAccessI implements Serializable{ 7XDze(O5  
ZQ_&HmgRy  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 vrr`^UB2  
RandomAccessFile oSavedFile; yJMHm8OB7  
long nPos; q]}1/JZS  
;V:Cf/@@R  
<8?jn*$;\  
public FileAccessI() throws IOException 2\'5LL3  
{ UomO^P  
this("",0); #R#o/@|  
} c9<&+  
nWzGb2Y  
~=#jr0IZ  
public FileAccessI(String sName,long nPos) throws IOException Qk_Mx"  
{ |Ox!tvyr  
oSavedFile = new RandomAccessFile(sName,"rw"); "KhVS  
this.nPos = nPos; c8=@s#  
oSavedFile.seek(nPos); giNyD4uO  
} i4p2]Nr t  
M9J^;3Lrh  
>.}ewz&9o  
public synchronized int write(byte[] b,int nStart,int nLen) jaOt"iU.B  
{ $(PWN6{\r^  
int n = -1; zB@@Gs>  
try{ OpT0V]k^"9  
oSavedFile.write(b,nStart,nLen); XY*KWO  
n = nLen; V!3.MQM  
} 'aAay*1  
catch(IOException e) rf:CB&u  
{ Jemb0Qv  
e.printStackTrace (); Z^?YTykH  
} ~p'DPg4  
/U1 jCLR'  
J]=2] oI2  
return n; w?db~"T  
} Dj$W?dC"^  
l*0`{R  
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} j1hx{P'  
CNRiK;nQ  
[ ]LiL;A&  
/* "p[FFg  
**SiteInfoBean.java VJ'bS9/T  
*/ N:yyDeGyW  
package NetFox; 9tZ+?O5  
5%Xny8 ]|D  
Pqc+pE  
public class SiteInfoBean { ;[[GA0  
(9X>E+0E  
`;OEdeAM  
private String sSiteURL; //Site's URL Wt8=j1>  
private String sFilePath; //Saved File's Path ~ ""?:  
private String sFileName; //Saved File's Name r:n-?P  
private int nSplitter; //Count of Splited Downloading File 5uJ{#Zd  
^HM9'*&KJ  
B<A=U r  
public SiteInfoBean() iO?Sf8yJ:  
{//nSplitter的缺省值为5 *?Pbk+}%  
//default value of nSplitter is 5 TM1D|H  
this("","","",5); $!-a)U,w$B  
} _);;@T  
4qc0QA%  
3"pl="[*  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) TiF2c#Q*y  
{ ;&9A Yh.  
sSiteURL= sURL; *z{.9z`  
sFilePath = sPath; _?IP}}jA:  
sFileName = sName; )ZP-t!).G#  
this.nSplitter = nSpiltter; >aaHN1Ca  
_H(:$=$Q  
HR> X@g<c  
} [61T$.  
WV8?zB1  
lW8!_h"G`n  
public String getSSiteURL() NL-<K  
{ !]v&/  
return sSiteURL; NxyrP**j  
} g^qbd$}  
~_YU%y  
5Tt%<#4  
public void setSSiteURL(String value) o3oA
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{ YV 5kzq  
sSiteURL = value; ZvS|a~jO  
} E{-W#}#  
KJf~9w9U  
5jYZ+OB  
public String getSFilePath() Q5N;MpJ-  
{ ^:yg,cS|Be  
return sFilePath; pOz
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} *YI>Q@F9  
9u->.O: p  
vG7aT  
public void setSFilePath(String value) ^z^ UFW  
{ :<}.3Q?&  
sFilePath = value; -}W`  
} WRWcB  
mu!hD^fw  
H:DTvv8e{  
public String getSFileName() mh4`,N  
{ tl:+wp7P`  
return sFileName; ~D9VjXfL)  
} )L%i"=<Bdy  
&>Ko}?w  
J6)&b7  
public void setSFileName(String value) =:!$'q:  
{ GG}(*pOr  
sFileName = value; J7C2:zj  
} SuHv{u45  
mN9Uyz5G  
k$hNibpkt  
public int getNSplitter() ;{Sgv^A  
{ e0#/3$\aSV  
return nSplitter; 2[*r9%W  
} VS:UVe  
cVR3_e{&H  
=>0+BD  
public void setNSplitter(int nCount) aC&ZV}8of  
{ zP|y3`.52  
nSplitter = nCount; <KFE.\*Z4  
} *F
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} ?rD`'B  
^lP_{c  
?QnVWu2K  
/* SnhB$DG  
**Utility.java RRNoX}  
*/ ;bZIj`D(  
package NetFox; /cy'% .!  
iuX82z`  
CulU?-[i  
public class Utility { \rw/d5.  
iE|qU_2Y  
S!<1CFh  
public Utility() =.]>,N`C  
{ w
w]^H$In  
sp0j2<$a  
CFW\  
} b83__i  
w :w  
//线程睡眠 O>E2G]K]\  
public static void sleep(int nSecond) $hkMJ),T~  
{ ~)zoIM\  
try{ A-GRuC  
Thread.sleep(nSecond); CZ/bO#~  
} jDp]}d|f)  
catch(Exception e) J#0oL_xY#  
{ V0gk8wD  
e.printStackTrace (); Ch1+YZG  
} lD8&*5tDmP  
} 5PJB<M_m:  
$Yr'`(Cbc  
//日志 XcS8{  
public static void log(String sMsg) PC_#kz  
{ ? 9.V@+i  
System.err.println(sMsg); $>3/6(bW  
} #nE%.k|R~  
z|Hc=AU8y  
FA.h?yfr  
public static void log(int sMsg) Q}J'S5%  
{ %0PdN@I  
System.err.println(sMsg); CWVCYm@!kz  
} _u`NIpXSP  
} 0.}Um  
Ufz& 2  
LiyEF&_u  
/* hSZ0 }/  
**TestMethod.java S^GB\uJ  
*/ 0x}8}  
package NetFox; !9!kb  
-}lcMZY  
+$#YW5wy  
public class TestMethod { '8NKrI  
1@nGD<,.  
%`%xD>![  
public TestMethod() _jw A_  
{ ///xx/weblogic60b2_win.exe {(7D=\eU  
try{ uv++Kj!  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 7L[HtwI  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); c3gy{:lb  
SiteFileFetch fileFetch = new SiteFileFetch(bean); <ByR!Y  
fileFetch.start(); 8t$a8 PE  
} t5z6{`  
catch(Exception e){e.printStackTrace ();} `L(AvSR  
y)W.xR  
^|6%~jkD5  
} W^2Q"c#
7F  
{d\erG
(  
()}B]?  
public static void main(String[] args) 1n! JfsU  
{ APT'2-I_  
new TestMethod(); AW8"@  
} P!C!E/Jf5  
} ny5= =C{9  
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