http断点续传简单实现（java)

/* <3=k  
**SiteFileFetch.java ^;\6ju2  
*/ z|S4\Ae  
package NetFox; 7-9HCP  
import java.io.*; (\%+id|/q@  
import java.net.*; lfwBUb  
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cj[%.M5iBA  
public class SiteFileFetch extends Thread { H66~!J0;a  
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SiteInfoBean siteInfoBean = null; //文件信息Bean [f$pq5f='  
long[] nStartPos; //开始位置 &mA{_|>  
long[] nEndPos; //结束位置 z^%`sUgP  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 REk^pZ3B  
long nFileLength; //文件长度 !+
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boolean bFirst = true; //是否第一次取文件 ry* 9  
boolean bStop = false; //停止标志 q'biTn]2  
File tmpFile; //文件下载的临时信息 =_2(S6~  
DataOutputStream output; //输出到文件的输出流 N$Tzxs  
]tbl1=|  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） }k8&T\V!  
public SiteFileFetch(SiteInfoBean bean) throws IOException wG22ffaki  
{
~%: TE}  
siteInfoBean = bean; +]VW[$W  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); :?#wWF.  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 0J= $ A  
if(tmpFile.exists ()) BT5~MYBl  
{ kh>i#9Ie  
bFirst = false; '}P$hP_d  
read_nPos(); C\cZ  
} 
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else a-5#8  
{ gGbqXG^  
nStartPos = new long[bean.getNSplitter()]; u)P)r,  
nEndPos = new long[bean.getNSplitter()]; `M_w^&6+n  
} %9t=Iu*  
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} f{D~ZC.*  
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public void run() !t&C,@Ox  
{ u$x'P <b  
//获得文件长度 o-]8)G>~M  
//分割文件 B :1r;8{j  
//实例FileSplitterFetch \&Oc}]  
//启动FileSplitterFetch线程 ]#$rTWMl'  
//等待子线程返回 x^UAtKSy  
try{ HR?a93  
if(bFirst) '494^1"io  
{ G0x!
:[  
nFileLength = getFileSize(); '[[*(4a3  
if(nFileLength == -1) [8`^_i=#  
{ ery{>|k  
System.err.println("File Length is not known!"); #w)D ml  
} xEe3,tb'e  
else if(nFileLength == -2) 3:!5 ]  
{ BOW`{=  
System.err.println("File is not access!"); Vdf~rV  
} e= _7Q.cn  
else |\q@XCGei  
{ J)=Ts({  
for(int i=0;i<nStartPos.length;i++) =Xb:.  
{ ,V=]QHcg  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); OV$|!n  
} dxWG+S  
for(int i=0;i<nEndPos.length-1;i++) 8d\/  
{ Oj.xJ(uX+v  
nEndPos = nStartPos[i+1]; TbhsOf!  
} to'O;f">n  
nEndPos[nEndPos.length-1] = nFileLength; L>2gx$f  
} 4:XVu
  
} kS(v|d  
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//启动子线程 N
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; yvKKE  
for(int i=0;i<nStartPos.length;i++) 1|#j/  
{ KHt#mQy)9  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), zzyD'n7D  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), !X/O1PM|  
nStartPos,nEndPos,i); m9f[n
T  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); VaylbYUCT/  
fileSplitterFetch.start(); }kb6;4>c
 
} 14rX:z  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), [c#?@S_  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 5!^?H"#c  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", (W$>!1~  
nEndPos = " + nFileLength); TInp6w+u  
// fileSplitterFetch[nPos.length-1].start();  Wwo`R5  
uF\f>E)/N%  
l#%G~c8x  
//等待子线程结束 %KmhR2v  
//int count = 0; )u_[cEJHO  
//是否结束while循环 ]AdL  
boolean breakWhile = false; 5B+I
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q#1CmKt4R  
zvP>8[ 
 
while(!bStop) wE09
%  
{ zRF+D+  
write_nPos(); $8Y|&P  
Utility.sleep(500); wg 6
 
breakWhile = true; -Mufo.Jz1o  
a6.0$'  
^>!~%Vv7!  
for(int i=0;i<nStartPos.length;i++) ,zH\&D$>u  
{ N'RUtFqj  
if(!fileSplitterFetch.bDownOver) R//S(eU68\  
{ &dI;o$t  
breakWhile = false; Y^J/jA0\B  
break; q#!c6lG  
} E,:E u<  
} "+KAYsVtU  
if(breakWhile) /s~&$(d59o  
break; c9N5c  
V(6ovJpA0  
!mRDzr7  
//count++; UG<`m]  
//if(count>4) S.A|(?x  
// siteStop(); !V;glx[  
} >>HC|  
cu$i8$?t  
$79-)4;z4  
System.err.println("文件下载结束！"); t:.ZvA3  
} bR;Wf5  
catch(Exception e){e.printStackTrace ();} AwO'%+Bv  
} 92S,W?(  
-axV;+"b  
.LHzaeJCX  
//获得文件长度 Y]Y]"y$1  
public long getFileSize() 9\D0mjn=l  
{ B(|dT66K  
int nFileLength = -1; hO}nc$S  
try{ nvnJVkL9s  
URL url = new URL(siteInfoBean.getSSiteURL()); ?e+$?8l[3  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ~`Xu6+1o  
httpConnection.setRequestProperty("User-Agent","NetFox"); :*{\oqFn~$  
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rCdf*;  
int responseCode=httpConnection.getResponseCode(); qJrMr4:F  
if(responseCode>=400) vAp?Zl?g  
{ ;Q} H'Wg,  
processErrorCode(responseCode); Q.Ljz Z  
return -2; //-2 represent access is error K+s xO/}h  
} KdB9Q ;  
-6u#:pVpU  
MW6
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String sHeader; 0al8%z9e@  
{Lm%zdk*k  
xg2 
&  
for(int i=1;;i++) '+{dr\nJ  
{ 3?R QPP  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ;BM
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//Utility.log(in.readLine()); 86,$ I+  
sHeader=httpConnection.getHeaderFieldKey(i); =q
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if(sHeader!=null) "G`8>1tO_  
{ @|GKNW#  
if(sHeader.equals("Content-Length")) ^9C9[$Q  
{ ~NtAr1  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); #UpxF?A(  
break; !p~K;p,  
} |6.1uRFE2  
} a\PvRW*I  
else H\Jpw  
break; p-t*?p C  
} 2dF:;k k  
} op%?V:  
catch(IOException e){e.printStackTrace ();} [d_sd  
catch(Exception e){e.printStackTrace ();} on q~wEr  
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Utility.log(nFileLength); \!tS|h  
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return nFileLength; q;V1fogqI)  
} $iblLZhj  
t[
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//保存下载信息（文件指针位置） xf.2Ig  
private void write_nPos() >xt*(j&}  
{ MXxE)"G*a  
try{ P00pSRQHD  
output = new DataOutputStream(new FileOutputStream(tmpFile)); K{&b "Ba1  
output.writeInt(nStartPos.length); 42m}c1R  
for(int i=0;i<nStartPos.length;i++) /j1p^
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{ O<x53MN^  
// output.writeLong(nPos); +RO=a_AS  
output.writeLong(fileSplitterFetch.nStartPos);
[,|Z<  
output.writeLong(fileSplitterFetch.nEndPos); [n_H9$   
} DgLSDKO!  
output.close(); > HL8hN'q'  
} '*KP{"3\  
catch(IOException e){e.printStackTrace ();} DjT ekn  
catch(Exception e){e.printStackTrace ();} M\s^>7es  
} -0)So  
~"*;lT5KX  
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//读取保存的下载信息（文件指针位置） pw7_j;}l  
private void read_nPos() UI4X
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{ Vo%UiVHy  
try{ diLjUC`69  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ,QpDz{8  
int nCount = input.readInt(); A_t<SG5  
nStartPos = new long[nCount]; O;A/(lPW+  
nEndPos = new long[nCount]; ]rh)AE!Y(  
for(int i=0;i<nStartPos.length;i++) "iof -b=ys  
{ 8bX\^&N  
nStartPos = input.readLong(); \?} {wh8  
nEndPos = input.readLong(); &\C{,:[  
} $Q:5KNF+p  
input.close(); L#e|t0'#  
} DOXRU5uP3  
catch(IOException e){e.printStackTrace ();} *4zVK/FJ  
catch(Exception e){e.printStackTrace ();} "z }bgy  
} /Ki :6  
N[}XLhbt  
V,uhBMT#
  
private void processErrorCode(int nErrorCode) A&5$eGe9  
{ ubhem(p#  
System.err.println("Error Code : " + nErrorCode); 'Ph4(Yg  
} EMH?z2iGd  
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^}8_tZs8\  
//停止文件下载 f ( `.q  
public void siteStop() )^!-Aj\x  
{ U[S;5xeF.j  
bStop = true; ^;YD3EZw  
for(int i=0;i<nStartPos.length;i++) i[ BR"(  
fileSplitterFetch.splitterStop(); 2|~&x~  
?<w +{  
-o#0Yt}3  
} >?e*;f$VdJ  
} e_6 i896  
//负责部分文件的抓取 JoZC+G  
**FileSplitterFetch.java xuelo0h,  
*/ "0L@cOyG  
package NetFox; /]xd[^  
j.CC.[$g  
YA^9, q6u?  
import java.io.*; CSU>nIE0  
import java.net.*; :B- ,*@EU  
{uj9fE,)  
j)F~C8*  
public class FileSplitterFetch extends Thread { %h%r6EB1F  
Ro:-u7q  
S0=BfkHi.  
String sURL; //File URL *OF7{^~&  
long nStartPos; //File Snippet Start Position 73xI8  
long nEndPos; //File Snippet End Position l}AB):<Z  
int nThreadID; //Thread's ID ^:-%tpB#!  
boolean bDownOver = false; //Downing is over Gz*U?R-T  
boolean bStop = false; //Stop identical dm$:xE":  
FileAccessI fileAccessI = null; //File Access interface kd\G>  
.yWdlq##  
6}ax~wYct  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException uR"]w7=  
{ +[2lS54"W4  
this.sURL = sURL; 00pHnNoxW  
this.nStartPos = nStart; 1shvHmrV  
this.nEndPos = nEnd; 5o~Z>  
nThreadID = id; EoY#D'[  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 w#b~R^U  
} )kUq2-r  
?qK:P  
3!$rp- !<)  
public void run() 5WZLB =  
{ 9DtSYd/  
while(nStartPos < nEndPos && !bStop) E$G"R=  
{ [=E<iPl  
&P{%C5?{  
*/8\Z46z  
try{ 50H[u|  
URL url = new URL(sURL); oW+R:2I~O  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); FySK&  
httpConnection.setRequestProperty("User-Agent","NetFox"); 98O z  
String sProperty = "bytes="+nStartPos+"-"; 1g/mzC
  
httpConnection.setRequestProperty("RANGE",sProperty); Bv=Z*"Fv  
Utility.log(sProperty); rfPJBD{Ve  
*pWswcV/  
!E7/:t4  
InputStream input = httpConnection.getInputStream(); ;%82Z4  
//logResponseHead(httpConnection); d#z67Nl6
  
"{0kg'fU  
N]=.I   
byte[] b = new byte[1024]; uPp(l4(+  
int nRead; ohh 1DsB  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) OQsH,'
  
{ cALu  
nStartPos += fileAccessI.write(b,0,nRead); RZ.5:v6  
//if(nThreadID == 1) X>wQYIi  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); JqZ%*^O  
} Aio0++r-  
"iydXV=Q  
vMI\$E&  
Utility.log("Thread " + nThreadID + " is over!"); [}AcCXg`L  
bDownOver = true; 3?}SXmA'@  
//nPos = fileAccessI.write (b,0,nRead); O>>8%=5Q  
} l;;:3:  
catch(Exception e){e.printStackTrace ();} >3Y&jsh<  
} . }1!MK5  
} kB:R-St  
hmi15VW  
kR_[p._  
//打印回应的头信息 HYY|)Wo  
public void logResponseHead(HttpURLConnection con) v]1rH$  
{ bBQp:P?E  
for(int i=1;;i++) U--ER r8  
{ =Vv{td  
String header=con.getHeaderFieldKey(i); lwB!
ti  
if(header!=null) w])Sz*J  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); _8`|KY  
Utility.log(header+" : "+con.getHeaderField(header)); :H87x?e[  
else \E30.>%,  
break; YJ0[BcZ  
} =wQ=`  
} _\<M58/z  
B
ZBsE :(F  
p[$I{F*a  
public void splitterStop() YUH/t
l  
{  e?7paJ  
bStop = true; r5"/EMieh  
} ZAP+jX;  
(/Mc
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} 4>W`XH  
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:)z_q!$j  
/* ^/+sl-6/F  
**FileAccess.java c'6H@m#=  
*//文件访问(定位，写) 8+u8piG  
package NetFox; gM*s/,;O"  
import java.io.*; Vh<`MS0X  
7~16letQ  
P8jK yo  
public class FileAccessI implements Serializable{ YJy*OS_&  
HT&0i,`  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 zxh"@j$?  
RandomAccessFile oSavedFile; = `^jz}  
long nPos; =~h54/#[I  
s*I
fXv  
6~}H
3rvO}  
public FileAccessI() throws IOException EDo (  
{ |h7v}Y  
this("",0);
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} ST3qg6Cq2J  
>4\xcL  
B'Wky>5)  
public FileAccessI(String sName,long nPos) throws IOException w.8~A,5}Dh  
{ 'G

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oSavedFile = new RandomAccessFile(sName,"rw"); g|P hNo  
this.nPos = nPos; "jHN#}  
oSavedFile.seek(nPos); CytpL`&^]  
} pR"qPSv'  
-db+Y:xUZ  
z)%1i  
public synchronized int write(byte[] b,int nStart,int nLen) l
K4+8VZ  
{ 4(R2V]  
int n = -1; fo.m&mKgo  
try{ +[ItkfSod!  
oSavedFile.write(b,nStart,nLen); nR7\ o(!  
n = nLen; e0L;V@R  
} ,:`6x[ +  
catch(IOException e) '!R,)5l0h  
{ Cu:Zn%  
e.printStackTrace (); Xo`1#6xsE  
} AJT0)FCpR  
v\Ljm,+  
|
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return n; FT~^$)8=  
} =lwS\mNs  
K +~v<F  
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} f[IchCwX  
sD8S2  
]lUu%<-;  
/* o(P:f)B  
**SiteInfoBean.java RY{tX`  
*/ ju]]|  
package NetFox; &wN 2l-  
#E9['JnZ
 
'l|_$3  
public class SiteInfoBean { yr>bL"!CA  
;
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x1wxB 1)2  
private String sSiteURL; //Site's URL 2?QJh2  
private String sFilePath; //Saved File's Path Q$1K{14I  
private String sFileName; //Saved File's Name Nd!VR+IZ  
private int nSplitter; //Count of Splited Downloading File N^+ww]f?  
6mdnEmFM]  
F"xO0t  
public SiteInfoBean() ~-5@- V  
{//nSplitter的缺省值为5 D,\=zX;  
//default value of nSplitter is 5 prtxE&-  
this("","","",5); k`TJ<Dv;  
} (GG"'bYk  
KIo}Gd&  
>Mw &Tw}o  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) #ja`+w}  
{ P0xL
x  
sSiteURL= sURL; !dY:S';~  
sFilePath = sPath; bZ.N7X PH  
sFileName = sName; +ZKhmb!  
this.nSplitter = nSpiltter; iwQ-(GjM[A  
"Vq]|j,B/c  
4Umsc>yfK  
} aLi_Hrb9  
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M"^Vf{X^  
public String getSSiteURL() 5vft}f  
{ @@83PJFid  
return sSiteURL; _wNPA1q0J  
} pFTlhj)1  
7Zt\G-QV  
lGUV(D  
public void setSSiteURL(String value) :(>9u.>l?5  
{ nud=uJ"(  
sSiteURL = value; nKB&|!
 
} xn@0pL3B~  
WEtA4zCO  
`8;,&<U'`  
public String getSFilePath() cTd;p>:>m  
{ =`~Z@IbdI  
return sFilePath; 3]<re{)J9O  
} H'{?aaK|t  
Ia`JIc^e  
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public void setSFilePath(String value) BD7@Mj*|  
{ t*d >eK`:N  
sFilePath = value; &4Con%YU[  
} `E5"Pmg  
@GQ8q]N:<  
!?o$-+a|  
public String getSFileName() ^YR|WKY  
{ oD#>8Aws  
return sFileName; kq~[k.  
} rEyz|k:  
,LW+7yD  
\c~{o+UD-  
public void setSFileName(String value) knOnUU  
{ ^8NLe9~p3?  
sFileName = value; ~sIGI?5f  
} [z%?MIT  
zk5=Opmvh  
"6N~2q,SW  
public int getNSplitter() ,.jHV  
{ 7grt4k  
return nSplitter; D!}K)T1~R  
} /.)[9bQ<  
-~\.n  
6f?BltFaN  
public void setNSplitter(int nCount) 7q!yCU  
{ tB7K&ssi  
nSplitter = nCount; .L7Yf+yFg  
} /^
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} *)bd1B#  
B9e.-Xaf  
|Vwc/9`t]>  
/* g TXW2S  
**Utility.java +K;Y+ K&;2  
*/ X#DL/#z k  
package NetFox; ')5L_$  
J4G> E.8  
px_s@>l`  
public class Utility { ~
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z0 2}&^Zzk  
x(9;!4O>  
public Utility() Fkcx+
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{ Jf?S9r5Q  
Er"R;l]xJ  
LgP>u?]n  
} Qq T/1^imS  
kqD*TJA  
//线程睡眠 >wKu6- ]a  
public static void sleep(int nSecond) [O7w =  
{ {b'}:aMc  
try{ 
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Thread.sleep(nSecond); A{z>D`d  
} 3+(yI 4  
catch(Exception e) ]eYd8s+  
{ %9T~8L @.  
e.printStackTrace (); SbS$(Gt#Bv  
} u3Usq=Ij{  
} +_ *eu  
x*me'?q  
//日志 dUoWo3r=  
public static void log(String sMsg) E+}GxFG-:  
{ vZb|!#I  
System.err.println(sMsg); -c+>j  
} >-5td=:Z  
.!yWF?T8  
1mHwYT+  
public static void log(int sMsg)  ofMu3$Q  
{ ZD5I5  
System.err.println(sMsg); uw
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} VY/|WD~"CW  
} j-J(C[[9  
]By0Xifew  
|*^8~u3J"  
/* uW}Hvj;0a*  
**TestMethod.java URYZV8=B~  
*/ q.=^iz&m  
package NetFox; =oE_.ux\  
5LQk8NPh  
JFkN=YR8  
public class TestMethod { WI1T?.Gc   
:7p9t.R<$h  
O87"[c`>  
public TestMethod() { p1lae  
{ ///xx/weblogic60b2_win.exe v:rD3=M-  
try{ 6exI_3A4jh  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); lSH ZV Fd  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); XkPv*%Er8  
SiteFileFetch fileFetch = new SiteFileFetch(bean); #^|| ]g/N  
fileFetch.start(); (n=9c%w  
} !1a}| !Zn  
catch(Exception e){e.printStackTrace ();} -$+,]t^GV  
gtD  
t< sp%zXZ  
} w&p~0cA~  
_*s~`jn{H  
P+Wm9xR2d  
public static void main(String[] args) 7\I
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{ j~Q}F|i8  
new TestMethod(); A LXUaE.  
} Q |
 
} t]s94 R q  
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