http断点续传简单实现（java)

/* ZA+w7S
3  
**SiteFileFetch.java %E2b{Y;  
*/ BIh^b?:zU  
package NetFox; Mz6PH)e;  
import java.io.*; $W]}m"l  
import java.net.*; ")YD~ZA%)  
=6'Fm$R  
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public class SiteFileFetch extends Thread { oJ?,X^~_  
\IaUsx"#o{  
U#Wg"W{  
SiteInfoBean siteInfoBean = null; //文件信息Bean WZM  
long[] nStartPos; //开始位置 UR~s\m  
long[] nEndPos; //结束位置 ub
;:"ns}  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 v>0I=ut  
long nFileLength; //文件长度 p"
"\uG'  
boolean bFirst = true; //是否第一次取文件 +"1fr  
boolean bStop = false; //停止标志 X;]Ijha<*  
File tmpFile; //文件下载的临时信息 \q@Co42n\  
DataOutputStream output; //输出到文件的输出流 gA}?X  
zfw=U \  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 3Fw7q"  
public SiteFileFetch(SiteInfoBean bean) throws IOException <?>tjCg'  
{ o~7D=d?R  
siteInfoBean = bean; H<") )EJI  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); v{SZ(;  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); {l"(EeW6)  
if(tmpFile.exists ()) uaE
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{ zY9CoadZ  
bFirst = false; 3i1TBhs6  
read_nPos(); Ae\:{[c_D  
} {T-=&%||  
else B$M4f7  
{ wk#cJ`wG;  
nStartPos = new long[bean.getNSplitter()]; lVCnu>8  
nEndPos = new long[bean.getNSplitter()]; :%_h'9Qq  
} U@9v(TfV  
&F:%y(;{Y  
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} D-FT3Culw  
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public void run() U(gYx@   
{ (&SPMhs_|(  
//获得文件长度 #(QS5J&Qq  
//分割文件 +Sc2'z>R  
//实例FileSplitterFetch pgQ^w0BQV  
//启动FileSplitterFetch线程 /dO*t4$@?  
//等待子线程返回 T|,/C|L  
try{ .W\JvPTC  
if(bFirst) $*`E;}S0  
{ h=Q2 ?O8  
nFileLength = getFileSize(); VTU(C&"S  
if(nFileLength == -1) EU Z7?4o  
{ 
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System.err.println("File Length is not known!"); osc A\r  
} nDcH;_<;9a  
else if(nFileLength == -2) w
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{ [dFe-2u ,$  
System.err.println("File is not access!"); `
=S%!akj  
} x2TE[#><  
else WcQkeh3n  
{ *mH&Gn1  
for(int i=0;i<nStartPos.length;i++) ,Wtgj=1!.  
{ &@FufpPw/  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); T% GR{mp  
} <Sr:pm  
for(int i=0;i<nEndPos.length-1;i++) >{l b|Vx  
{ KrR`A(=WL  
nEndPos = nStartPos[i+1]; 1BgHkDW  
} H_,4N_hL  
nEndPos[nEndPos.length-1] = nFileLength; 1]9l SE!E7  
} #0?3RP  
} p2U6B  
L1WvX6  
*pDS%,$xe  
//启动子线程 U&43/;<,  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; V>`9ey!U  
for(int i=0;i<nStartPos.length;i++) 5`@yX[G  
{ ii&ckg>]z  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), %g^:0me`  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), X,c`,B03  
nStartPos,nEndPos,i); "_2;+@+  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 8H1&=)M=  
fileSplitterFetch.start(); QeN7~ J  
} );h  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), XD" 4t4~>  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); "&{.g1i9  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 6J_
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nEndPos = " + nFileLength); :;c`qO4  
// fileSplitterFetch[nPos.length-1].start(); 2a;[2':  
W7;R
Q  
'v@*xF/L6a  
//等待子线程结束 @=%g{  
//int count = 0; `4?|yp.|L  
//是否结束while循环 ty:{e]e  
boolean breakWhile = false; =f23lA  
kGL3*x  
'MW O3  
while(!bStop) <EdNF&S-  
{ +z0s)HU>j  
write_nPos(); qu^~K.I"  
Utility.sleep(500); u{w,y.l1h  
breakWhile = true; *K& $9fah  
F(ZczwvR  
>vR2K^  
for(int i=0;i<nStartPos.length;i++) +~*e B  
{ z_=V6MDM  
if(!fileSplitterFetch.bDownOver) 17`-eDd  
{ ?*[35XUd  
breakWhile = false; hd,O/-m#  
break; wCV~9JTJ!  
} cnRg
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} bvHQ#:}H  
if(breakWhile) L4ct2|w}ul  
break; j/F('r~L  
kem(U{m  
A`Rs n\  
//count++; -%Ce  
//if(count>4) =diGuIB  
// siteStop(); |f\WVGH  
} ZD7q

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KV-h~C  
;.rY`<|  
System.err.println("文件下载结束！"); JS
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} ]vPdj"7  
catch(Exception e){e.printStackTrace ();} $pt~?ZZ3-  
} %mD{rG9  
G{O{ p  
ic4hO>p&  
//获得文件长度 ?>I  
public long getFileSize() lgD%  
{ g>#}(u!PH  
int nFileLength = -1; | +uc;[`  
try{ vP+qwvpGr  
URL url = new URL(siteInfoBean.getSSiteURL()); i)Q d>(v  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); G'';VoW=  
httpConnection.setRequestProperty("User-Agent","NetFox"); =;F7h @:  
\zwm:@lG  
.>~er?-  
int responseCode=httpConnection.getResponseCode(); U_.}V  
if(responseCode>=400) c.5u \I9"  
{ \rO!lvX  
processErrorCode(responseCode); 3xKgj5M  
return -2; //-2 represent access is error &Nw|(z&$  
} _ b</ ::Tp  
XX "3.zW  
ie>mOsz  
String sHeader; 8J
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1)qD)E5&cf  
5R%y3::$S  
for(int i=1;;i++) +EqL|  
{ ):nC%0V  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Xy`'h5  
//Utility.log(in.readLine()); R3LIN-g(  
sHeader=httpConnection.getHeaderFieldKey(i); ZR"qrCSw`  
if(sHeader!=null) _meW9)B  
{ :7JP(j2  
if(sHeader.equals("Content-Length")) rx@i.+  
{ ZG{#CC
=  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); d2)]6)z6  
break; U[OUIXUi  
} XW\ 3ttx  
} #yU"n-eLR  
else %o0H#7'  
break; pp{GaCi  
} e**'[3Y  
} *65~qAd  
catch(IOException e){e.printStackTrace ();} z]LVq k  
catch(Exception e){e.printStackTrace ();} hN\sC9a1  
#JY>  
"3|OB, <;:  
Utility.log(nFileLength); -j:yEZ4Oy  
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Pj_DI)^  
return nFileLength; f^F"e'1  
} SQ]M"&\{y  
sIl&\g<b  
h(3-/4  
//保存下载信息（文件指针位置） 4L4u
<  
private void write_nPos() lz1cLl m  
{ -)KNsW  
try{ opu)9]`z  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 1jAuW~  
output.writeInt(nStartPos.length); eN
M"
e-  
for(int i=0;i<nStartPos.length;i++) 2+pXtP@O  
{ w>}n1Nc$G  
// output.writeLong(nPos); rY1jC\  
output.writeLong(fileSplitterFetch.nStartPos); @xso{$z?j  
output.writeLong(fileSplitterFetch.nEndPos); eb6y-TwY  
} ^gNbcWc7CU  
output.close(); ~?)y'?  
} 0ia-D`^me  
catch(IOException e){e.printStackTrace ();} v6E5#pse8  
catch(Exception e){e.printStackTrace ();} ]1|7V|N6  
} <Lt"e8Z>x  
rSm#/)4A  
gQ%mVJB{(  
//读取保存的下载信息（文件指针位置） II[-6\d!  
private void read_nPos() Ge=\IAj  
{ 'WBhW5@  
try{ b^(
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DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); {a9.0N:4  
int nCount = input.readInt(); ~ahu{A4Bw  
nStartPos = new long[nCount]; CyB4apJ  
nEndPos = new long[nCount]; ,OP\^  
for(int i=0;i<nStartPos.length;i++) 4!-R&<TLve  
{ !x||ObW\H  
nStartPos = input.readLong(); )nK+`{;@!  
nEndPos = input.readLong(); 1=!2|D:C)i  
} 9>vB,8  
input.close(); &Fjyi"8(r  
} +&J1D8  
catch(IOException e){e.printStackTrace ();} bxBndxl  
catch(Exception e){e.printStackTrace ();} m5HMtoU  
} kGakdLl  
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private void processErrorCode(int nErrorCode) xon^=Wo;  
{ c?GV  
System.err.println("Error Code : " + nErrorCode); jIHY[yDT  
} jZvIqR/  
:O?3lj)  
6Bexwf<u  
//停止文件下载 hewc5vrL  
public void siteStop() 7uF @Xh  
{ &zVXd  
bStop = true; IlI5xkJ(  
for(int i=0;i<nStartPos.length;i++) PpNG`_O  
fileSplitterFetch.splitterStop(); ^EW6}oj[  
/'_Yct=  
1]A\@(  
} G Uh<AG*+  
} !|9
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//负责部分文件的抓取 5Fq+^  
**FileSplitterFetch.java jMX|1b  
*/ rg 0u#-  
package NetFox; {!wd5C@  
$"}
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IF<T{/MA  
import java.io.*; |%3>i"Y@AK  
import java.net.*; /5 OQ0{8p  
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YG*}F|1  
public class FileSplitterFetch extends Thread { |S]fs9  
73{<;z}i  
(OavgJ+Y  
String sURL; //File URL D$w?  
long nStartPos; //File Snippet Start Position -$@'@U  
long nEndPos; //File Snippet End Position Ywcgt|  
int nThreadID; //Thread's ID q6%m .X7  
boolean bDownOver = false; //Downing is over km`";gUp>  
boolean bStop = false; //Stop identical 5>=4$!`  
FileAccessI fileAccessI = null; //File Access interface f3h]t0M  
qNMYZ0,  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException [[Nn~7  
{ LA(/UA3Izd  
this.sURL = sURL; j<9^BNl  
this.nStartPos = nStart; *<?KOM  
this.nEndPos = nEnd; ^?A>)?Sq  
nThreadID = id; gd]_OY7L  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ]!/R tt  
} 5a2;@}%V  
3#\C!T0y  
ld5+/"$
 
public void run() zY-?Bv_D  
{ qzSm]l?z  
while(nStartPos < nEndPos && !bStop) zU4*FXt  
{ ,XN4Iy#BZl  
vo~Qo;m  
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try{ Wrt5eYy  
URL url = new URL(sURL); zcio\P=^|B  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); `nc=@" 1  
httpConnection.setRequestProperty("User-Agent","NetFox"); n*#HokX  
String sProperty = "bytes="+nStartPos+"-"; TIF =fQ  
httpConnection.setRequestProperty("RANGE",sProperty); Wi~?2-!   
Utility.log(sProperty); 'I>geW?{QK  
OL@
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GNW.n(a  
InputStream input = httpConnection.getInputStream(); 'c >^Aai  
//logResponseHead(httpConnection); zqRps8=  
o+- 0`!yj  
};gcM@]]E  
byte[] b = new byte[1024]; i@%a!].I  
int nRead; 6!=q+sw/X  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Vp1Nk#H  
{ 1.Neg|  
nStartPos += fileAccessI.write(b,0,nRead); {Wr5F9q  
//if(nThreadID == 1) 7$*x&We  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); rf!i?vAe  
} 5)->.*G*  
M`)3(|4  
EQ"+G[j~x  
Utility.log("Thread " + nThreadID + " is over!"); [3x*47o"z  
bDownOver = true; 'S9jMyZrZ  
//nPos = fileAccessI.write (b,0,nRead); !?K#f?x<?  
} sn'E}.uhXH  
catch(Exception e){e.printStackTrace ();} }"
/>,  
} "wxyY^"  
} uOh
  
~{{7y]3M-  
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!  
//打印回应的头信息 gTdr  
public void logResponseHead(HttpURLConnection con) h66mzV:`  
{ _d>{Hz2  
for(int i=1;;i++) \#C]|\  
{ i7&ay\+@  
String header=con.getHeaderFieldKey(i); ~;t/VsgGW  
if(header!=null) ^5k~7F.  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); X2YBZA  
Utility.log(header+" : "+con.getHeaderField(header)); Ak3V< =gx  
else Qr-,
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break;  / w[Tu  
} yEkwdx5!(  
} ^pqJz^PO.  
 7b8y
 
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public void splitterStop() FvD/z;N  
{ ~h3~<p#M`  
bStop = true; g?@fHFct  
} wb39s^n  
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} *{O[}  
xgvwH?<  
{?r5~T`2  
/* Sj viH  
**FileAccess.java uu/2C \n}  
*//文件访问(定位，写) Ve xxdg  
package NetFox; yMpZ-b$*~  
import java.io.*; Qn;,OBk  
ghTue*A  
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public class FileAccessI implements Serializable{ vLGnLpt  
u$D%Iz  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 [7,q@>:CS  
RandomAccessFile oSavedFile; m@",Zr`f=  
long nPos; h1$75E?,  
h"f_T [  
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public FileAccessI() throws IOException K.b:ae^k  
{ j?\z5i""f  
this("",0); NC sem  
} #1WCSLvtV  
Q9&H/]"v  
%Y9CZRY9  
public FileAccessI(String sName,long nPos) throws IOException vX&W;&  
{ /*t H$\6*  
oSavedFile = new RandomAccessFile(sName,"rw"); gOm8 O,  
this.nPos = nPos; r$Oa  
oSavedFile.seek(nPos); c IPOI'3d  
} a.
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ju1B._48  
:BB=E'293  
public synchronized int write(byte[] b,int nStart,int nLen) yl0;Jx?  
{ H
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int n = -1; ryb81.|  
try{ F(Je$c/J|~  
oSavedFile.write(b,nStart,nLen); N686~  
n = nLen; 2AEVBkF;M  
} ZzxWKIE'c  
catch(IOException e) eYevj[c;  
{ h-DHIk3/  
e.printStackTrace (); beNy5~M$  
} ~y,m7%L  
'1~;^rU  
s&XL{FE  
return n; 7;pQ'FmZJ  
} bRr3:"=sE  
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} M C y~~DL  
PZI6{KOis  
m>*~tP  
/* }i^$ li@  
**SiteInfoBean.java `Q[NrOqe"  
*/ +zEyCx=8H  
package NetFox; hS&.-5v  
(O&HCT|  
yR"mRy1  
public class SiteInfoBean { lNTbd"}$:  
5qFHy[IA  
ZH~Wn#Wp  
private String sSiteURL; //Site's URL "]\3t;IT  
private String sFilePath; //Saved File's Path rbl^ aik  
private String sFileName; //Saved File's Name 8\jsGN.$JZ  
private int nSplitter; //Count of Splited Downloading File &=XK:+  
k *>"@  
7xfS%'=y"  
public SiteInfoBean() 3$.#\*s_4  
{//nSplitter的缺省值为5 Mq_P'/  
//default value of nSplitter is 5 ? 51i0~O=  
this("","","",5); "]OROJGa  
} ,sT5TS q  
I1I-,~hO  
<kWkc|zBY  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) "=V!-+*@G@  
{ U2v;GIo$yU  
sSiteURL= sURL; <(H<*Xf9  
sFilePath = sPath; <j3|Mh_(I  
sFileName = sName; eHR]qy 0_X  
this.nSplitter = nSpiltter; A4rkwM  
E()%IC/R  
Ys|SacWC  
} ?C
x=!k.  
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7 D{%  
public String getSSiteURL() G,<l}(tEG  
{ Z*-a=u%gl'  
return sSiteURL; S)/548=`  
} #T@k(Bz{L  
2\;/mQI2A  
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public void setSSiteURL(String value) |dDKO  
{ ZT8LMPC  
sSiteURL = value; T|0d2aa  
} "oyBF CW  
\xcf<y
3_  
KP7 {  
public String getSFilePath() ~Yc!~Rz  
{ D4uAwmc  
return sFilePath; V^rL  
} 5=%KK3  
iio-RT?!  
y~su1wUp  
public void setSFilePath(String value) G6+6uWvl  
{ )P
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sFilePath = value; EY:H\4)  
} p}5413z5Z=  
oB~V~c}8x  
@;N(3| n7  
public String getSFileName() i%, 't  
{ j(k}NWPH  
return sFileName; b*/Mco 9O  
} #=;
vg  
/Gn0|]KI  
DIJmISk  
public void setSFileName(String value) )dh`aQ%N "  
{ RD=V`l{Z  
sFileName = value; L&~'SC  
} upX@8WxR  
H6Bw3I[  
f^
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public int getNSplitter() B|,d  
{ Z
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return nSplitter; yqVoedN  
} X8-x$07)  
?~(#~3x  
@|bJMi  
public void setNSplitter(int nCount) mx UyD[|  
{ s`0IyQXVU  
nSplitter = nCount; 3:xKq4?  
} HFlExau  
}  sFnR;  
#9F>21UU  
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/* V!>j:"  
**Utility.java 9v?@2sOoE  
*/ !2^~ar{2  
package NetFox; WuFBt=%  
W0Y ,3;
0  
5jUy[w @  
public class Utility { D$*o}*mb  
Yl:[b{Py  
{cb<9Fii  
public Utility() ;r&Z?B$  
{ o*ucw3s>  
4nQ5zwiV  
M ?AX:0  
} 1ltW9^cF}  
p>#q* eU5  
//线程睡眠 hUuKkUR+Ir  
public static void sleep(int nSecond) }`%ks  
{ 57 Bx-  
try{ .\&k]}0qA?  
Thread.sleep(nSecond); ?u/UV,";y  
} {?2|rv)  
catch(Exception e) }p?67y/  
{ |lg jI!iK  
e.printStackTrace (); <;O^3_'  
} (DS"*4ty  
} 8 H3u"  
kFC*,  
//日志 VX>j2Z'  
public static void log(String sMsg) 5Pxx)F9]  
{ zSU,le  
System.err.println(sMsg); oif|X7H;  
} [u37Hy_Gi  
I%GQ3D"=  
)9[u*|+  
public static void log(int sMsg) )tnbl"0  
{ eU,FYJt9  
System.err.println(sMsg); K"&^/[vMB  
} OK8Ho"  
} cofdDHXfQI  
`wQs$!a
  
}f14# y;  
/* s=F[.X9lp  
**TestMethod.java G6}&k[d5%  
*/ X1o^MMpz(F  
package NetFox; 4>LaA7)v  
*|<~IQg  

wfpl]d!  
public class TestMethod { LHXR7Fjc  
&5${k'  
H(P]Z~et  
public TestMethod() >]xW{71F@  
{ ///xx/weblogic60b2_win.exe hITYBPqRO  
try{ @"1Z;.S8V  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); .4tu{\YX  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); P:N>#G~z  
SiteFileFetch fileFetch = new SiteFileFetch(bean); FfrC/"N  
fileFetch.start(); #D|%r-:"  
} <hiv8/)?  
catch(Exception e){e.printStackTrace ();} ViMl{3  
(V\N1T,f  
K/ &`  
} ,(zV~-:9  
Tsj/alC[  
~cfXEjE6  
public static void main(String[] args) *w O~RnP  
{ HKI\i)c  
new TestMethod(); _SOwiz  
} `O%nDry  
} b;5j awG  
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