http断点续传简单实现（java)

/* ?U+^ctwv7  
**SiteFileFetch.java )IN!CmpN  
*/ _}8hEv  
package NetFox; d
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import java.io.*; OCR`1  
import java.net.*; ~<[$.8*  
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public class SiteFileFetch extends Thread { y.h2hv]Bc  
7.V'T=@x3)  
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SiteInfoBean siteInfoBean = null; //文件信息Bean )-yJKmV  
long[] nStartPos; //开始位置 9g%1^$R  
long[] nEndPos; //结束位置 ]Rah,4?9f  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Udj
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long nFileLength; //文件长度 fC6zDTis8A  
boolean bFirst = true; //是否第一次取文件 3<Qe'd ^  
boolean bStop = false; //停止标志 %t&
  
File tmpFile; //文件下载的临时信息 \YXzq<7  
DataOutputStream output; //输出到文件的输出流 tOUpK20q.@  
i_/
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） +qN}oyL  
public SiteFileFetch(SiteInfoBean bean) throws IOException j1[Ng #.  
{ Vf28R,~m  
siteInfoBean = bean; MR")  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 0PfjD  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Uk@du7P1k  
if(tmpFile.exists ()) ky2n%<0]  
{ BQ8vg8e]B  
bFirst = false; is?#wrV=K  
read_nPos(); rlUo#  
} q<Tx'Ya  
else o2AfMSt.  
{  kwI[BF  
nStartPos = new long[bean.getNSplitter()]; NUSb7<s,&Y  
nEndPos = new long[bean.getNSplitter()]; D\13fjjHlu  
} V\1pn7~V  
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*dmBJi}  
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} OKW}8q
M  
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public void run() 
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{ Jcy{ ~>@7  
//获得文件长度 FX
1[ 2\  
//分割文件 pCacm@(hG  
//实例FileSplitterFetch "Zh3,  
//启动FileSplitterFetch线程 P8&BtA  
//等待子线程返回 `kE ;V!n?  
try{ RA];hQI?  
if(bFirst) o]R
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{ KM-d8^\:  
nFileLength = getFileSize(); 1>~bzXY#  
if(nFileLength == -1) -hd@<+;E  
{ #BLx +mLq  
System.err.println("File Length is not known!"); pL [JGn  
} ( *&E~g  
else if(nFileLength == -2) RpmOg  
{ Py@/\V  
System.err.println("File is not access!"); X}V}%  
} gWK[%.Jnw  
else 0|i3#G_~  
{ pY~/<lzW  
for(int i=0;i<nStartPos.length;i++) jw 4B^2}  
{ WilKC|R]P  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Zk:Kux[7  
} ?Yf0h_>  
for(int i=0;i<nEndPos.length-1;i++) mJU1n  
{ -v@LJCK7I  
nEndPos = nStartPos[i+1]; ]z77hcjB1  
} *\$m1g7b  
nEndPos[nEndPos.length-1] = nFileLength; C%RYQpY*c  
} !B*l'OJw  
} +nAbcBJAl  
4*U5o!w1{  
6 2*p*t  
//启动子线程 qr@<'wp/  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; VY#
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for(int i=0;i<nStartPos.length;i++) ?zk#}Ex1  
{ E4QLXx6Wa&  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), y2`},  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), .QvH7  
nStartPos,nEndPos,i); 7:C_{\(  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 6 l,8ev  
fileSplitterFetch.start(); &7J-m4BI  
} %&iodo,EP'  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), +0l-zd\  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Q\W?qB_  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", {*PbD;/f  
nEndPos = " + nFileLength); jLM}hwJ8  
// fileSplitterFetch[nPos.length-1].start(); ` n#Db  
L*#W?WMM v  
VbI$#;:[7  
//等待子线程结束 |Cm6RH$(  
//int count = 0; Ee3-oHa  
//是否结束while循环 ,{C hHnJ%#  
boolean breakWhile = false; :<P3fW  
2MU$OI0|  
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while(!bStop) BjyV&1tRV!  
{ $Ph#pM(  
write_nPos(); #E$*PAB  
Utility.sleep(500); %,UTFuM`  
breakWhile = true; /lS5B6NU  
}'p"q)  
}&LVD$Bz  
for(int i=0;i<nStartPos.length;i++) R>D
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{ *'cyFu$  
if(!fileSplitterFetch.bDownOver) jwL\|B oE  
{ E[ttamU  
breakWhile = false; l`<1Y|  
break; ^)p+)5l   
} J kxsua  
} .<zN/
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if(breakWhile) z -c1,GOD  
break; 6Zl#$>P  
?={S"qK(q  
5Q/jI$^h0Z  
//count++; ]!X[[w)  
//if(count>4) Kw7uUJR  
// siteStop(); yvWM]A  
} 9RPZj>ezjA  
;(-Wc9=  
Ge`PVwn  
System.err.println("文件下载结束！"); c6T[2Ig  
} LzQOzl@z  
catch(Exception e){e.printStackTrace ();} >{)\GK0i7  
} -V&nlP  
~l8w]R3A  
}nRTw2-z  
//获得文件长度 }X/>WiGh:  
public long getFileSize() K!,9qH  
{ Yosfk\D  
int nFileLength = -1; TWM^5 L:U  
try{ W#@6e')d  
URL url = new URL(siteInfoBean.getSSiteURL()); {.])'~[U  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); =o:1Rc7J  
httpConnection.setRequestProperty("User-Agent","NetFox"); /K(l[M  
N9#5 P!  
J9/EJ'My  
int responseCode=httpConnection.getResponseCode(); Z*+y?5+L"P  
if(responseCode>=400) Z<iK(?@O  
{ \1O wZ@  
processErrorCode(responseCode); t"Bp# U1  
return -2; //-2 represent access is error #p<(2wN  
} _fdD4-2U  
jmG)p|6  
9tWpxrig%  
String sHeader; j+PLtE  
PA*1]i#2M=  
T/PmT:Qg`  
for(int i=1;;i++) |'``pq/}_  
{ t*J?#r  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); rvacCwI  
//Utility.log(in.readLine()); P(UY}oU  
sHeader=httpConnection.getHeaderFieldKey(i); *nK4XgD  
if(sHeader!=null) lA`qB1x  
{ V a
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if(sHeader.equals("Content-Length")) ,A5}HRW%  
{ ?kK3%uJy&  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); {9FL}Jrt  
break; R7 rO7M!  
} =M6{{lI/  
} "A*;V  
else {
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break; n?>|2>  
} {oS/Xa  
} qu\U^F  
catch(IOException e){e.printStackTrace ();} h$#PboLd  
catch(Exception e){e.printStackTrace ();} -,+~W#n  
}5;/!P_A  
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Utility.log(nFileLength); XmP,3KG2{S  
8!b>[Nsc  
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return nFileLength; D~FIv  
} Y>T<Qn^D  
jNI9 .45y  
w9StW94p  
//保存下载信息（文件指针位置） }mo)OyIX  
private void write_nPos() dlA0&;}z  
{ (-],VB (+  
try{ IR{XL\WF  
output = new DataOutputStream(new FileOutputStream(tmpFile));
u_}UU 2  
output.writeInt(nStartPos.length); K^",LCJA  
for(int i=0;i<nStartPos.length;i++) 86eaX+F  
{ a)*(**e$*i  
// output.writeLong(nPos); iaJLIrl  
output.writeLong(fileSplitterFetch.nStartPos); E5#ff5  
output.writeLong(fileSplitterFetch.nEndPos); 6HPuCP  
} LLFQ5py{  
output.close(); l_4^TYF  
} Cd]g+R}j  
catch(IOException e){e.printStackTrace ();} P'o]#Az  
catch(Exception e){e.printStackTrace ();} ^
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} 1>/ iYf  
v$xurj:v#i  
=4sx(<  
//读取保存的下载信息（文件指针位置） 505ejO|  
private void read_nPos() (5A8#7a  
{ F-F1^$]k  
try{ Fn0|v66  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 6b%IPbb  
int nCount = input.readInt(); ArjRoXDE  
nStartPos = new long[nCount]; )w5!'W4Z8  
nEndPos = new long[nCount]; P#MUS_x  
for(int i=0;i<nStartPos.length;i++) F vTswM>  
{ .<E7Ey#  
nStartPos = input.readLong(); H )>3c1  
nEndPos = input.readLong(); .2U3_1dX  
} ]t~'wL#Z  
input.close(); Mnk-"d  
} ,c0t#KgQ.  
catch(IOException e){e.printStackTrace ();} E3(o}O  
catch(Exception e){e.printStackTrace ();} Vc6 >i|"-O  
} +*Fe   
D>^g2!b:  
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private void processErrorCode(int nErrorCode) H!6+x*P
0  
{ (sI`FW_  
System.err.println("Error Code : " + nErrorCode); cq5^7.  
} M]M>z>1*v  
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7SN61)[m  
//停止文件下载 acar-11_o/  
public void siteStop() L0I|V[  
{ <CJy3<$u  
bStop = true; "',;pGg|K  
for(int i=0;i<nStartPos.length;i++) 7KGb2V<t  
fileSplitterFetch.splitterStop(); ]
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eh>FYx( S  
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} H|7XfM  
} *_d N9  
//负责部分文件的抓取 x4MTE?hT  
**FileSplitterFetch.java 4<vi@,s  
*/ I(WIT=Wi<  
package NetFox; Y@<jvH1  
=}@1Z~  
%!AzFL J|Z  
import java.io.*; Vugb;5Vl  
import java.net.*;
#qUGc`  
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public class FileSplitterFetch extends Thread { ,L.V>Ae  
_"OE}$C  
'/OQ[f=K  
String sURL; //File URL @Kn@j D;  
long nStartPos; //File Snippet Start Position yTn<5T[H  
long nEndPos; //File Snippet End Position ^16zZ*
 
int nThreadID; //Thread's ID
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boolean bDownOver = false; //Downing is over e2K9CE.O  
boolean bStop = false; //Stop identical &cd>.&1<2  
FileAccessI fileAccessI = null; //File Access interface p@Cas  
T$AVMVq  
A0RSNAM  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException FzP1b_i  
{ @/ nGc9h  
this.sURL = sURL; hg:$H9\%  
this.nStartPos = nStart; eX lJ=S
}  
this.nEndPos = nEnd; *W^a<Zm8>  
nThreadID = id; gHkHAOe/  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ?Bl/bY$*h  
} &r*F+gL  
()w;~$J  
`S5::U6E  
public void run() {]Cn@.TPD  
{ $.:x3TsA  
while(nStartPos < nEndPos && !bStop) }~NXiUe  
{ ^nN
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I.(@#v7T  
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try{ Pa+_{9  
URL url = new URL(sURL); `u R`O9)e  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 1c429&-  
httpConnection.setRequestProperty("User-Agent","NetFox"); WRAL/  
String sProperty = "bytes="+nStartPos+"-"; _%Ua8bR$  
httpConnection.setRequestProperty("RANGE",sProperty); C"mWO Y2]  
Utility.log(sProperty); lN8l71N^  
1 ?Zw  
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InputStream input = httpConnection.getInputStream(); Cz$q"U  
//logResponseHead(httpConnection); $-~"G,;F  
,nCvA%B!  
CWRB/WH:  
byte[] b = new byte[1024]; +Mhk<A[s  
int nRead; %W2U$I5  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) f[.'V1  
{ rlawH}1b  
nStartPos += fileAccessI.write(b,0,nRead); ~Hv>^u Mh  
//if(nThreadID == 1) J .TK<!  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); $~/cxLcT  
} r\FZ-gk}Q  
Iz-mUD0;  
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Utility.log("Thread " + nThreadID + " is over!"); PB.'huu  
bDownOver = true; fH?A.JP=a  
//nPos = fileAccessI.write (b,0,nRead); HB$?}V  
} 12hD*,A5j  
catch(Exception e){e.printStackTrace ();} XGbpH<
 
} 'Ha> >2M  
} vdQ#CG$/  
INp:;  
`4X.UPJ  
//打印回应的头信息 5*-RIs! 2  
public void logResponseHead(HttpURLConnection con) m"n" 1;o=  
{ 4[JF.O6}  
for(int i=1;;i++) Ycq )$7p  
{ 98O]tL+k/u  
String header=con.getHeaderFieldKey(i); GCiG50Z=  
if(header!=null) u*W! !(P/  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); zJl;|E".  
Utility.log(header+" : "+con.getHeaderField(header)); /V`SJ"  
else L6i|5 P  
break; k~K;r8D/  
} S:`Gi>D  
} 0sH~yvM5  
|HYST`  
%6rSLBw3  
public void splitterStop() V9qA'k  
{ Oq,@{V@)9k  
bStop = true; >;Vfs{Z(q  
} &7>]# *  
*| W*Mu  
+F8K%.Q_  
} kaiK1/W0;  
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/* ^Go,HiB  
**FileAccess.java W2fcY;HZ  
*//文件访问(定位，写) =3A4.nW  
package NetFox; vM!2?8bEFd  
import java.io.*; XzX2V">(%  
iWC}\&i  
)?{!7/H F@  
public class FileAccessI implements Serializable{ Q_!tn*  
2#3`[+g<n  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 <H-kR\HF  
RandomAccessFile oSavedFile; MMC$c=4"  
long nPos; &z5?]`ALu  
1%R${Qhr  
D.%%D%AdB  
public FileAccessI() throws IOException &!O?h/&X3  
{ ZWGX*F#}P  
this("",0); (VI(Nv:o@  
} Jr;w>8B),  
)\VuN-d  
sJ^Ff  
public FileAccessI(String sName,long nPos) throws IOException -64;P9:A>  
{ '[%Pdd]! E  
oSavedFile = new RandomAccessFile(sName,"rw"); 3`{;E{  
this.nPos = nPos; DEhR\
Z!  
oSavedFile.seek(nPos); Ta/zDc"e  
} 2|i
1}  
F.i}&UQ%  
+Yq?:uBV  
public synchronized int write(byte[] b,int nStart,int nLen) W94u7a  
{ OPE+:TvW^  
int n = -1; bp}97ZQ  
try{ `Npo|.?=  
oSavedFile.write(b,nStart,nLen); kdlmj[=  
n = nLen; fp\mBe
i  
} YQFz6#Ew  
catch(IOException e) =54D#,[B  
{ hCF_pt+  
e.printStackTrace (); AB,(%JT/2{  
} s-'~t#h  
EA1&D^nT  
B[EOz\?
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return n; ;r~1TUKb  
} %saP>]o  
}qoId3iY!7  
r(Z?Fs/  
} Gf
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&Ejhw3Nw  
bpU>(j  
/* cZF|oZ6<  
**SiteInfoBean.java @4Bl&(3S  
*/ Xf#;`*5  
package NetFox; :E|Jqi\  
"nfi:A1  
,X:3w3nr^  
public class SiteInfoBean { x7^VU5w#  
517wduj  
.E+O,@?<  
private String sSiteURL; //Site's URL &[j9Up'   
private String sFilePath; //Saved File's Path ')yYpWO  
private String sFileName; //Saved File's Name Vj1V;d
Hv  
private int nSplitter; //Count of Splited Downloading File ~}d\sQF.  
A-3^~aEgx  
J(!=Dno  
public SiteInfoBean() 7A'E+>1d  
{//nSplitter的缺省值为5 e&:%Rr]x  
//default value of nSplitter is 5 L'`Au/%S}  
this("","","",5); L
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} KaOXqFT=  
}Rh%bf7,  
'U ZzH$h  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) vL[IVBG^  
{ R2{]R&wtn0  
sSiteURL= sURL; Uf7ACv)Dn  
sFilePath = sPath; "fhQ{b$i  
sFileName = sName; /AOGn?Z3  
this.nSplitter = nSpiltter; 'm|T"Ym~  
bo<.pK$  
IgwHC0W  
} !s/qqq:g  
Qnt}:M+  
Nl,iz_2]  
public String getSSiteURL() +$VDV4l  
{ u{\>iQ
  
return sSiteURL;
W)D?8*  
} B<-("P(q  
)eZ}Kt+  
_w%:PnO  
public void setSSiteURL(String value) }|) N5bGQe  
{ 4ME$Z>eN  
sSiteURL = value; fH_l2b[-3@  
} ;r6YIS4@  
;~$Q;m1  
"x$L2>9  
public String getSFilePath() M[O22wFs  
{ fJ _MuAv  
return sFilePath; R<Mp$K^b  
} {:_*P TVk  
=?+w5oI0  
T95FoA  
public void setSFilePath(String value) _7';1 D  
{ !ii(2U  
sFilePath = value; \}kR'l  
} gpzFY"MS=  
.mqMz
V  
NX(+%EBcA
 
public String getSFileName() %x@bP6d[  
{ Eu
l3 {+]  
return sFileName; s 72y
u}  
} &FOq c  
/y
4A?*w6  
83_mR*tGNp  
public void setSFileName(String value) \8\TTkVSq  
{ 3*j1v:x`  
sFileName = value; CH!\uK22  
} nm%qm  
m1]/8{EC7  
o%z^@Cq  
public int getNSplitter() RL]$"  
{ Xg1TX_3Ml  
return nSplitter; a_[+id  
} 4Wa$>v
z  
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"5FP$oR  
public void setNSplitter(int nCount) S5F5Tr;TN  
{ {2 T:4i5  
nSplitter = nCount; F=*t]X[z}  
} #hs&)6Sf  
} QhRj*,  
<6hs<qXqi  
nTs\zikP  
/* roG<2i F  
**Utility.java b5jD /X4  
*/ | a i#rU  
package NetFox; >QN-K]YLL  
,-k?"|tQ  
"d~<{(:N^  
public class Utility { jVGAgR=[G  
?y>v"1+  
a Iyzt  
public Utility() -AVT+RE9z  
{ )>Z@')Uk:  
Mg8ciV}\xY  
~p{YuW[e  
} ]{{%d4  
.}+3A~  
//线程睡眠 MZA%ET,l,<  
public static void sleep(int nSecond) *>W6,F7  
{ ^c.pvC"4j
 
try{ rP"Y.;s  
Thread.sleep(nSecond); y/_=  
} }7{(o-  
catch(Exception e) ##F$8d)q  
{ mAIl)mq|g  
e.printStackTrace (); 2Z<S^9O9  
} S7cD}yx*[  
} i88`W&tI{  
(k"0/*F4_  
//日志 'zMmJl}\vd  
public static void log(String sMsg) F/tRyq`D  
{ Wie0r@5E  
System.err.println(sMsg); F8tMZ,:  
} .ty2! .  
gw
g~4:W  
j1K~zG  
public static void log(int sMsg) GuL0:,  
{ QL2LIs  
System.err.println(sMsg); F`,bFQ  
}  myOW^  
} ^Dfqc-]  
K~^o06 Y  
egfd=z=2un  
/* 4PU@W o  
**TestMethod.java D0S^Msk9L  
*/ ~WV1t][  
package NetFox; k@n L(2  
"OkZ [E)  
ix?Z:pIS0  
public class TestMethod { rXTdhw?+  
"av/a  
e9S*^2;  
public TestMethod() \fUVWXv  
{ ///xx/weblogic60b2_win.exe B"*PBJuOA  
try{ ga;t`5+d  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); F60m]NUM)c  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); KlBT9"6"  
SiteFileFetch fileFetch = new SiteFileFetch(bean); l#+@!2z  
fileFetch.start(); |r+hj<K  
} i \lr KA  
catch(Exception e){e.printStackTrace ();} 7VkjnG^!:  
6BQq|:U  
YCzH@94QeV  
} ?h#F& y  
PqyR,Bcx0  
Y1qbu~!  
public static void main(String[] args) `r\/5|M  
{ +8|Xj!!*}  
new TestMethod(); !l.^]|  
} Ln\Gv/)  
} i#4E*B_-  
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