http断点续传简单实现（java)

/* ;FcExg|k  
**SiteFileFetch.java b#Jo Xa9  
*/ K q/~T7Ru  
package NetFox; Oq[i &  
import java.io.*; \Oz,Qzr|  
import java.net.*; m';#R9\Fz  
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public class SiteFileFetch extends Thread { >kt~vJI  
{ip=iiW2  
#>@<n3rq  
SiteInfoBean siteInfoBean = null; //文件信息Bean <Kh?Ad>N  
long[] nStartPos; //开始位置 ?_8%h`z  
long[] nEndPos; //结束位置 T.J`S(oI  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Xm%iPrl D  
long nFileLength; //文件长度 2ve lH;  
boolean bFirst = true; //是否第一次取文件 V;H d)v(j  
boolean bStop = false; //停止标志 ^@M[t<  
File tmpFile; //文件下载的临时信息 O<4Q$|=&?  
DataOutputStream output; //输出到文件的输出流 2wGF-V  

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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 4U}zJP(L  
public SiteFileFetch(SiteInfoBean bean) throws IOException 4}+xeGA$  
{ zjea4>!A2  
siteInfoBean = bean; Akv(} !g  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); lj4%(rB=  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); B%TXw#|  
if(tmpFile.exists ()) P8"6"}B;T  
{ .V8/ELr]  
bFirst = false; C:rRK*  
read_nPos(); 7t ZW^dF  
} n?zbUA#  
else $Z,i|K;  
{ 3fm;r5  
nStartPos = new long[bean.getNSplitter()]; x(rd$oZO  
nEndPos = new long[bean.getNSplitter()]; aB=vu=hF  
} U)u\1AV5  
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} Q^*G`&w,  
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public void run() UCe,2v%  
{ zv$G
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//获得文件长度 ub[""M?  
//分割文件 <\E"clZI  
//实例FileSplitterFetch c9\B[@-q  
//启动FileSplitterFetch线程 os}b?I*K  
//等待子线程返回 yT[Lzv#  
try{ <sgZ3*,A  
if(bFirst) \_lG#p|  
{ |P^]
@om  
nFileLength = getFileSize(); '.]e._T  
if(nFileLength == -1) ,DexJ1  
{ M4zX*&w.T  
System.err.println("File Length is not known!");
<P|`7wfxE  
} Ko1AaX(I'+  
else if(nFileLength == -2) Oyi;bb<#  
{ [B}1z  
System.err.println("File is not access!"); t9?R/:B%  
} [SCw<<l<  
else hO^&0
?  
{ hZp=BM"bJ  
for(int i=0;i<nStartPos.length;i++) 8]sTX9  
{ 'q{PtYr  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); >(IITt  
} /1IvLdPIu  
for(int i=0;i<nEndPos.length-1;i++) 6.7
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{ vh<]aiY  
nEndPos = nStartPos[i+1]; 4C l,Iw/;  
} o}WB(WsG  
nEndPos[nEndPos.length-1] = nFileLength; I(z>)S'7r  
} 4$0jz'  
} A Oby*c  
(iHf9*i CV  
B@ZqJw9J[  
//启动子线程 @o}1n?w  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; `V]egdO  
for(int i=0;i<nStartPos.length;i++) u&1j>`~qJ  
{ =nJOaXR0  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ,"P5D&,_  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), .'l.7t  
nStartPos,nEndPos,i); %MfGVx}nG  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 1bV2  
fileSplitterFetch.start(); T [T6
  
} @J~lV\  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), *Te4U5F  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 6Y;Y}E  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", S 23S.]r  
nEndPos = " + nFileLength); :'5G_4y)h  
// fileSplitterFetch[nPos.length-1].start(); =giM@MV  
:SpG&\+  
0MwG}|RC  
//等待子线程结束 *4(/t$)pEl  
//int count = 0; 03X<x|  
//是否结束while循环 "\VW.S  
boolean breakWhile = false; GOv92$e  

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c*y$bf<  
while(!bStop) v+xgxQGYH  
{ K!IF?iell  
write_nPos(); hKk\Y{wv'  
Utility.sleep(500); *23m-  
breakWhile = true; L LYHr  
Ov$N"  
uS! 35{.>  
for(int i=0;i<nStartPos.length;i++) 1$='`@8I  
{ t 3(%UB  
if(!fileSplitterFetch.bDownOver) o~i]W.SI(  
{ [47K7~9p  
breakWhile = false; ^>,<*p  
break; v YRt2({}Z  
} +zFV~]b  
} xFsB?d  
if(breakWhile) kWZ/ej  
break; JVJ1Ay/be  
j33P~H~  
)'BJ4[aq\  
//count++; E
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//if(count>4) >>oASo  
// siteStop(); dD/29b(  
} 1R5\GKF6o  
R$!;J?SS  
;4-pupK~%  
System.err.println("文件下载结束！"); 2x<Qt2"  
}
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catch(Exception e){e.printStackTrace ();} &=s|  
} Ft%TnEp  
T+AlcOP  
8
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//获得文件长度 ()@.;R.Z  
public long getFileSize() GL;x:2XA  
{ ch5`fm  
int nFileLength = -1; H6%!v1 u  
try{ <F#*:Re_y  
URL url = new URL(siteInfoBean.getSSiteURL()); .oi}SG  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); T3u5al  
httpConnection.setRequestProperty("User-Agent","NetFox"); D,}'E0  
$nGbT4sc  
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int responseCode=httpConnection.getResponseCode(); ^*cMry  
if(responseCode>=400) 3<zTkI  
{ 48 c D3w  
processErrorCode(responseCode); H y.3ccZ0  
return -2; //-2 represent access is error %468s7Q[Mi  
} #lBpln9  
J'G`=m"-'  
.R$+#_  
String sHeader; s0XRL1kWr  
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,E*a$cCw  
for(int i=1;;i++) ?RRSrr1  
{ e6{[o@aM{  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); .yK\
&q[<  
//Utility.log(in.readLine()); s3MMICRT.  
sHeader=httpConnection.getHeaderFieldKey(i); "W_jdE6v  
if(sHeader!=null) =M/UHOY  
{ Z!]U&Ax`Z  
if(sHeader.equals("Content-Length")) dbMu6Bm\G  
{ o-Q]Dk1W  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); lJ2|jFY9  
break; xu%! b0  
} Uf7F8JZmM  
} <\}Y@g8  
else fcE/  
break; .UT,lqEkv  
} <iXS0k  
} b2}QoJ@`  
catch(IOException e){e.printStackTrace ();} `L"p)5H  
catch(Exception e){e.printStackTrace ();} ga{25q}"  
:]u}xDv3  
6PzN>+t^y  
Utility.log(nFileLength); 7/^TwNsv  
,IT)zCpaBP  
}> !"SU:d  
return nFileLength; 8aZey_Hw;+  
} r7Q:l ?F2  
-_{C+Y
_  
l$p_])x  
//保存下载信息（文件指针位置） (Qx-KRH  
private void write_nPos() h87L8qh9  
{ h-2E9Z  
try{ OU)p)Y_z  
output = new DataOutputStream(new FileOutputStream(tmpFile)); L6rs9su=7  
output.writeInt(nStartPos.length); {x&jh|f`g  
for(int i=0;i<nStartPos.length;i++) *&hXJJ[+  
{ &-8-xw#.  
// output.writeLong(nPos); ~P]HG;$?n  
output.writeLong(fileSplitterFetch.nStartPos); -hG 9  
output.writeLong(fileSplitterFetch.nEndPos); r_g\_y7ua  
} Cb@S </b  
output.close(); 6wpND|cT  
} <PfPh~  
catch(IOException e){e.printStackTrace ();} CYFas:rPLT  
catch(Exception e){e.printStackTrace ();} G3_mWppH  
} YA;8uMqh;  
t'=~"?T/o  
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//读取保存的下载信息（文件指针位置） U&w5&W{F}  
private void read_nPos() f1
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{ {M)3GsP?  
try{ A=qW]Im  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 3'sWlhf;  
int nCount = input.readInt(); xPfnyAo?%z  
nStartPos = new long[nCount]; }<\65 B$1  
nEndPos = new long[nCount]; d,oOn.n&  
for(int i=0;i<nStartPos.length;i++) F"m}mf  
{ 3f:1D=f  
nStartPos = input.readLong(); Iu1Sj`A  
nEndPos = input.readLong(); 3|83
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} t0asW5f  
input.close(); 2LxVt@_R!%  
} ,3@15j  
catch(IOException e){e.printStackTrace ();} :|m~<'g  
catch(Exception e){e.printStackTrace ();} 7>2j=Y_Kp  
} S"KTL*9D  
~\)&{'  
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private void processErrorCode(int nErrorCode) V&,<,iNN  
{ 5cNzG4z  
System.err.println("Error Code : " + nErrorCode); (;2J(GZ:$U  
} {ck  
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//停止文件下载 vU$O{|J
 
public void siteStop() qs c-e,rl  
{ #Lxj )  
bStop = true; 0m+5Zn  
for(int i=0;i<nStartPos.length;i++) ~g4rGz  
fileSplitterFetch.splitterStop(); Q5Ghki  
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9Pob|UA  
} a5U2[Ko80  
} bF Y)o Z  
//负责部分文件的抓取 kkE)zF   
**FileSplitterFetch.java 3 ?|; on  
*/ <0Egkz3s  
package NetFox; aji~brq  
:7DVc&0  
^0ZKHR(}e  
import java.io.*; j=jrzG+`  
import java.net.*; HyX4ob[X  
eR* ]<0=  
.{]c&Ef+f  
public class FileSplitterFetch extends Thread { 8{4D|o#O  
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:AE;x&  
String sURL; //File URL <j8&u/Za~'  
long nStartPos; //File Snippet Start Position fkv{
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long nEndPos; //File Snippet End Position l#vw L15  
int nThreadID; //Thread's ID QRmQ>  
boolean bDownOver = false; //Downing is over g*AD$":  
boolean bStop = false; //Stop identical u&d v[  
FileAccessI fileAccessI = null; //File Access interface sO4}kxZ  
! ?U^+)^$  
|b'<XQ&l5  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException k89gJ5B$  
{ (+Kof  
this.sURL = sURL; '3_B1
iAv  
this.nStartPos = nStart; NK#"qK""k  
this.nEndPos = nEnd; _~S^#ut+  
nThreadID = id; WPp\sIP  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 "MS`d+rf\  
} l6DIsR  
*~<]|H5~  
7@y!R   
public void run() FiU;>t<)  
{ ~ %YTJS  
while(nStartPos < nEndPos && !bStop) komxot[[  
{ io?{ew  
s
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<,cIc]eX  
try{ \,bFm,kC?  
URL url = new URL(sURL); Y %D*O  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); >A(?Pn{|a  
httpConnection.setRequestProperty("User-Agent","NetFox"); qT>& v_<  
String sProperty = "bytes="+nStartPos+"-"; DdS3<3]A  
httpConnection.setRequestProperty("RANGE",sProperty); }Ka.bZS  
Utility.log(sProperty); 2hA66ar{$  
+i_f.Ipp  
CT:eV7<>s  
InputStream input = httpConnection.getInputStream(); KjfKo;T  
//logResponseHead(httpConnection); H"RF[bX(  
l0_E9qh-i  
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byte[] b = new byte[1024]; ?eVuz x  
int nRead; k-DB~-L  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) `# M.t);^  
{ *DI:MBJY  
nStartPos += fileAccessI.write(b,0,nRead); }
!7DF  
//if(nThreadID == 1) k$x 'v#  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); K\E]X\:  
} 4C9"Q,o%&  
:8|3V~%m  
*Qwhi&k  
Utility.log("Thread " + nThreadID + " is over!"); KRR^?  
bDownOver = true; |`;1p@w"  
//nPos = fileAccessI.write (b,0,nRead); ^sn>p}T
g  
} "`gZy)E  
catch(Exception e){e.printStackTrace ();} %b%<g%@i  
} i~s9Ot  
} Hkz~9p  
$HCAC4  
BaTOh'52  
//打印回应的头信息 ^]!1'xg  
public void logResponseHead(HttpURLConnection con) YM.IRj2/1  
{ /R$x-7t)^(  
for(int i=1;;i++) sS2E8Z2  
{ "KE38`NL  
String header=con.getHeaderFieldKey(i); d8 Nh0!  
if(header!=null) O+Lb***b"  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 5b4V/d* '  
Utility.log(header+" : "+con.getHeaderField(header)); . .je<  
else :!YJ3:\  
break; uZ?CVluP  
} U <$xp  
} nV xMo_  
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public void splitterStop() 'xXqEwi4  
{ M "P  
bStop = true; Y+`-~ 88  
} 0i(
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} DMZ aMY|  
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!E#.WX  
/* =RE_Urt:  
**FileAccess.java c7Qa !w  
*//文件访问(定位，写) Mciq9{8&  
package NetFox; A*U'SCg(G  
import java.io.*; B5r_+?=2e  
\bQ
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R*{?4NKG  
public class FileAccessI implements Serializable{ $yqq.#1  
2m_M9
e\  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 x[~OVG0M*  
RandomAccessFile oSavedFile; ]`H.qV  
long nPos; u0KZrz  
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7-g4S]r<  
public FileAccessI() throws IOException =&/a\z!  
{ p[cL#fBz  
this("",0); >!F,y3"5S  
} f\r4[gU@  
Zt0%E<C{  
:;Rt#!  
public FileAccessI(String sName,long nPos) throws IOException FY}*Z=D%  
{ yB{o_1tc  
oSavedFile = new RandomAccessFile(sName,"rw"); tskODM0Zf  
this.nPos = nPos; 2
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oSavedFile.seek(nPos); VEKITBs  
} :k/U7 2  
ftuQ"Ds  
;/3/R/^g  
public synchronized int write(byte[] b,int nStart,int nLen) gOmyFHv.  
{ I>o; %}  
int n = -1; |(v=1#
i  
try{ TZyQOjUu  
oSavedFile.write(b,nStart,nLen); XJ/kB8  
n = nLen; rw0lXs#K<E  
} aDv/kFfn  
catch(IOException e)
-mw\?\2{  
{ q&6=oss!  
e.printStackTrace (); ?,DbV|3_\  
} oYErG],  
Xq!tXJ)  
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return n; 24/~gft  
} 6="&K_Q7  
.p~;U|h"  
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} f
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/* R+hS;F nh%  
**SiteInfoBean.java q$'&RG  
*/ oxXW`C<  
package NetFox; 0BE^
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Z9~Wlt'?  
[F{a-i-  
public class SiteInfoBean { z9O/MHT[w  
|Z|xM  
8%f! X51  
private String sSiteURL; //Site's URL pv SFp-:_  
private String sFilePath; //Saved File's Path o`! :Q!+  
private String sFileName; //Saved File's Name Cfb-:e$0  
private int nSplitter; //Count of Splited Downloading File ; 2-kQK9  
''Ec-b6Q-  
e`1s[ ^B  
public SiteInfoBean() =u"|qD  
{//nSplitter的缺省值为5 Qug'B  
//default value of nSplitter is 5 >&Q. .`q  
this("","","",5); 1)Bi>X  
} :.df(1(RL  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) <r3n?w8  
{ vqZM89xY  
sSiteURL= sURL; 31Mc<4zI8  
sFilePath = sPath; y'/9KrV T  
sFileName = sName; IOqyqt'  
this.nSplitter = nSpiltter; XPTB,1g+f  
G_4P)G3H  
l #z`4<  
} =@XR$Uud6  
5D*V%v  
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public String getSSiteURL() *3($s_r>  
{ )/N! {`.9  
return sSiteURL; (1]@ fCd +  
} @Qozud\?  
C,u.!g;lm  
C YKGf1;If  
public void setSSiteURL(String value) ur7a%NH  
{ *OcptmY<  
sSiteURL = value; (5;xs  
} .e#j#tQp  
{z_pL^S'52  
.6#2i <oPW  
public String getSFilePath() h1)\.F4G  
{ Zotv]P2k  
return sFilePath; Av]N.HB$  
} 7z&u92dJI  
imQNfNm  
2Jv4l$$;*  
public void setSFilePath(String value) SX;IUvVE5  
{ 1bs95Fh9Q  
sFilePath = value; iO`f{?b  
}
bYH_U4b  
-v@^6bQVp  
k"zHrn"$  
public String getSFileName() YaNVpLA  
{ <qx-%6  
return sFileName; C( ;7*]  
} b6BIDuRb  
YO+d+5  
q[K)bg{HB  
public void setSFileName(String value) m:CpDxzbf  
{ SUhP e+  
sFileName = value; ,Z"sh*  
} /VkJ+%}+j  
s:P-F0q!&  
o*'3N/D~  
public int getNSplitter() WU_Q 7%+QS  
{
8+
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return nSplitter; 5]JXXdt  
} DLZ63'  
6}2Lt[>O  
$=R\3:j  
public void setNSplitter(int nCount) VEm[F/'  
{ 2Y{9Df  
nSplitter = nCount; !>j-j  
} SfT]C~#$N  
} ']x]X,  
PnvLXE}F  
B4=gMVp1  
/* enM 3  
**Utility.java (@9}FHJzi  
*/ u}_q'=<\  
package NetFox; dtm@G|Ij  
0nAS4Az  
`mVH94{+I  
public class Utility { [$X(i|6  
/qG?(3  
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public Utility() &(0);I@fc  
{ q~C6+  
QKxuvW  
#a|5A:g%  
} 9AaixI  
**"sru;@=  
//线程睡眠 V6N#%(?3  
public static void sleep(int nSecond) (?(ahtT4T  
{ UQy+&;#5  
try{ anYZ"GR+  
Thread.sleep(nSecond); 6 ?cV1:jh  
} ^m\n[<x^  
catch(Exception e) -v] 0@jNe  
{ _35?z"0  
e.printStackTrace (); 'yqp  
} Lm/^ 8V+  
} h/ic-iH(>  
%' Fc%3  
//日志 :tMWy m  
public static void log(String sMsg) Gf>T{Q`,is  
{ 1Low[i  
System.err.println(sMsg); N?p$-{  
} )erPp@  
UHHe~L  
JdnZY.{S0  
public static void log(int sMsg) 3[$VW+YV  
{ .KV?;{~q@  
System.err.println(sMsg); a<Ta*:R$0  
} @<+(40`*  
} 'tc$#f^:  
$xqphhBg  
F-t-d1w6  
/* ~ lS3+H  
**TestMethod.java M II]sF  
*/ >r3Wo%F'  
package NetFox; s_|wvOW)'  
4YJs4CB  
LQ._?35r  
public class TestMethod { );C !:?  
b^ZrevM  
:&]%E/  
public TestMethod() : f
Wh7X3  
{ ///xx/weblogic60b2_win.exe f3O3pIA  
try{ K>-m8.~\E  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); J_tJj8  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 3j2}n o8O  
SiteFileFetch fileFetch = new SiteFileFetch(bean); H$ v4N8D8I  
fileFetch.start(); }x+{=%~N  
} &Jj?C  
catch(Exception e){e.printStackTrace ();} &p*N8S8  
MTQdyTDHl  
sfH|sp  
} 0&Qn7L  
($-o"y"x  
h`)r :a7  
public static void main(String[] args) |tmD`ndO  
{ NWf!c-':  
new TestMethod(); p?%G|Q  
} dM)fr  
} I".r`$XZ  
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