http断点续传简单实现（java)

/* KXo[;Db)k  
**SiteFileFetch.java ;Ac!"_N?7  
*/ Fz$^CMw5K  
package NetFox; 7YU}-gi  
import java.io.*; N1]P3  
import java.net.*; I\6^]pi,  
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public class SiteFileFetch extends Thread { 0^MRPE|f5  
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SiteInfoBean siteInfoBean = null; //文件信息Bean `[4{]jX+<  
long[] nStartPos; //开始位置 4Cf.%f9@  
long[] nEndPos; //结束位置 Y#Pg*C8>8  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 k?Iq 6  
long nFileLength; //文件长度 OxVe}Fym  
boolean bFirst = true; //是否第一次取文件 rge/qUr/^  
boolean bStop = false; //停止标志 l9$"zEC  
File tmpFile; //文件下载的临时信息 @(e/Y/  
DataOutputStream output; //输出到文件的输出流 !o`h*G-x  
vj<JjGP  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） <~.1>CI9D3  
public SiteFileFetch(SiteInfoBean bean) throws IOException 0a's[>-'A  
{ h\OMWJ~  
siteInfoBean = bean; =&?BPhJE  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); V)Y#m/$`  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); h!]=)7x;  
if(tmpFile.exists ()) $)M5@KT  
{ ,y*|f0&"~  
bFirst = false; &B ^LaRg  
read_nPos(); mp>Ne6\Tu  
} 6t`cY  
else [`|gj  
{ HY7#z2L  
nStartPos = new long[bean.getNSplitter()]; w:[\G%yQ  
nEndPos = new long[bean.getNSplitter()]; e[L%M:e9U  
} N/N~>7f  
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} r1[Jo|4vo  
7,Q>>%/0P  
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public void run() p6W|4_a?  
{ *
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//获得文件长度 7,EdJ[CR$  
//分割文件 :5BVVa0oR  
//实例FileSplitterFetch }:hN}*H  
//启动FileSplitterFetch线程 rE$=~s  
//等待子线程返回 ?=0BU}  
try{ 5Z*6,P0  
if(bFirst) h7F5-~SpD  
{ zqa7!ky  
nFileLength = getFileSize(); ~-o[v-\  
if(nFileLength == -1) jS| 9jg:  
{ O p,_d^  
System.err.println("File Length is not known!"); 3/0E9'  
} [^2c9K^NK  
else if(nFileLength == -2) C0%yGLh&  
{ =/MA`>  
System.err.println("File is not access!"); gano>W0  
} 7Nt6}${=z  
else yJ?S7+b  
{ Q?]-/v  
for(int i=0;i<nStartPos.length;i++) f:J-X~T_f  
{ oDi+\0  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); :g^ mg-8  
} TOS'|xQ  
for(int i=0;i<nEndPos.length-1;i++) <1<xSr  
{ <yBa5m@/  
nEndPos = nStartPos[i+1]; w1aoEo"S  
} ylQj2B,CB  
nEndPos[nEndPos.length-1] = nFileLength; SO[ u4b_"h  
} xk7Dx}  
} *kYGXT,f]  
N#t`ZC&m'  
MtN!Xx  
//启动子线程 $60`Hh 4/  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; >V)"TZH  
for(int i=0;i<nStartPos.length;i++) gw[Eu>I  
{ n^O!93a  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ,u)jZ7  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), [;sTl~gC  
nStartPos,nEndPos,i); BOq9\g`5s  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); P?P.QK  
fileSplitterFetch.start(); %b4tyX:N0  
} `ZI-1&Y3  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), (K84J*;  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); X?n=UebO^  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", : T7(sf*!*  
nEndPos = " + nFileLength); VO=Ibu&X  
// fileSplitterFetch[nPos.length-1].start(); uZ\+{j=  

Z*UVbyC  
.kPNWNrw  
//等待子线程结束 n\JI7A}  
//int count = 0; 2l^_OrE!  
//是否结束while循环 7C,giCYU  
boolean breakWhile = false; y)CvlI  
[A"=!e$<  
GdVF;  
while(!bStop) jY]51B
 
{ Gsb^gd  
write_nPos(); N)R5#JX  
Utility.sleep(500); *L$_80  
breakWhile = true; " r o'?  
1 ptyiy  
[0]A-#J  
for(int i=0;i<nStartPos.length;i++) ZILJXX4  
{ "*F`,I3  
if(!fileSplitterFetch.bDownOver) ~QxW^DGa7]  
{ B%MdJD>  
breakWhile = false; pq&[cA_w  
break; K%x]:|,>M  
} IM/xBP  
} x-X~'p'f  
if(breakWhile) BI%XF 9{  
break; #u8#< ,w  
9q_{_%G%  
=W:=}ODD  
//count++; dr:x0>  
//if(count>4) Xo/H+[;X  
// siteStop(); cy;i1#1rO  
} s8>y&b.  
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2b^Fz0 w4  
System.err.println("文件下载结束！"); [WG\wj.  
} *qk7e[IP  
catch(Exception e){e.printStackTrace ();} liH#=C8l*%  
} 'Kbrz  
wL="p) TO.  
t&J A1|q  
//获得文件长度 seBmhe5qR  
public long getFileSize() >Bf3X&uS  
{ 2%`= LGQC  
int nFileLength = -1; G:tY1'5  
try{ P~=yTW  
URL url = new URL(siteInfoBean.getSSiteURL()); |vl~B|",  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); }_
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httpConnection.setRequestProperty("User-Agent","NetFox"); xUsL{24  
% ym};7'&b  
*K;)~@n  
int responseCode=httpConnection.getResponseCode(); :=ek~s.UV  
if(responseCode>=400) 51Y%"v t  
{ 2HN*j~>i~  
processErrorCode(responseCode); Bps%>P~.  
return -2; //-2 represent access is error a
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} Hxgc9Fis  
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".(vR7u'  
String sHeader; D_
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for(int i=1;;i++) ?dCwo;~  
{ PRaVe,5a  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); n
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//Utility.log(in.readLine()); "YgpgW  
sHeader=httpConnection.getHeaderFieldKey(i); kodd7 AD  
if(sHeader!=null) nk%v|ZxoFv  
{ $">j~!'  
if(sHeader.equals("Content-Length")) il@>b  
{ Dn 0L%?_  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); F!ztU8,  
break; {eaR,d~X  
} YxJQ^D
`  
} g}D)MlXRq  
else u5k{.&  
break; L4m Vk  
} `HXv_9  
} zH}3J}  
catch(IOException e){e.printStackTrace ();} 5buW\_G)  
catch(Exception e){e.printStackTrace ();} iiIns.V  
_Ik?WA_;  
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Utility.log(nFileLength); kP&I}R
Y  
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return nFileLength; Mp|Jt  
} cE 'LE1DK  
<Q9l'u]3$c  
_90D4kGU  
//保存下载信息（文件指针位置） ?`Yu~a{  
private void write_nPos() W{"sB:E  
{ ?I[8rzBWU  
try{ lTMY|{9  
output = new DataOutputStream(new FileOutputStream(tmpFile)); s"`~Xnf  
output.writeInt(nStartPos.length); m.m6.  
for(int i=0;i<nStartPos.length;i++) :&vX0 Ce:  
{ ?IHt T3'Rt  
// output.writeLong(nPos); uv/\1N;V3  
output.writeLong(fileSplitterFetch.nStartPos); jj2iF/  
output.writeLong(fileSplitterFetch.nEndPos); Intuda7e1  
} b},2A'X  
output.close(); G^k'sgy.  
} 5+M,X kg  
catch(IOException e){e.printStackTrace ();} `5?0yXK  
catch(Exception e){e.printStackTrace ();} `z(o01y  
} CsA(oX  
<WZ{<'ajI  
2lpPN[~d  
//读取保存的下载信息（文件指针位置） ))|d~m  
private void read_nPos() T:@6(_Z  
{ F%|P#CaB  
try{ W-s6+DY  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); l[$GOLeS  
int nCount = input.readInt(); cj>UxU][eS  
nStartPos = new long[nCount]; 7s?#y=M  
nEndPos = new long[nCount]; 7! >0  
for(int i=0;i<nStartPos.length;i++) z!3=.D
 
{ Qy"Jt]O  
nStartPos = input.readLong(); &S{r;N5u  
nEndPos = input.readLong(); ,XEIg  
} FprdP*/  
input.close(); ]{6/6jl  
} u>fMO9X}2  
catch(IOException e){e.printStackTrace ();} wkx9@?2*  
catch(Exception e){e.printStackTrace ();} %@Gy<t,  
} \s*UUODWK  
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private void processErrorCode(int nErrorCode) D wJ^ W&*  
{ mBErU6?X,A  
System.err.println("Error Code : " + nErrorCode); (`dz37@*  
} B<SE|~\2  
Ux=~-}<-w  
#("M4}~  
//停止文件下载 ,yGbMOV  
public void siteStop() YQN:&Cls  
{ E,6|-V;?  
bStop = true; O]PM L`  
for(int i=0;i<nStartPos.length;i++) _,L_H[FN  
fileSplitterFetch.splitterStop(); *0>`XK$mWo  
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!YAX.e  
} k5Cy/gR  
} D5c 8sB  
//负责部分文件的抓取 u @Ze@N%  
**FileSplitterFetch.java S=r0tao,!v  
*/ TxPFl7,r  
package NetFox; &RZO\ZT  
; R+>}6  
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import java.io.*; GfELL`yz  
import java.net.*; =6dAF"b)  
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jlj ge=#c2  
public class FileSplitterFetch extends Thread { 66pjWS {X  
Pj

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String sURL; //File URL ~6i'V?>  
long nStartPos; //File Snippet Start Position g9" wX?*  
long nEndPos; //File Snippet End Position F9o7=5WAb  
int nThreadID; //Thread's ID / rc[HbNg.  
boolean bDownOver = false; //Downing is over }dzdx"  
boolean bStop = false; //Stop identical @.-S(MNR  
FileAccessI fileAccessI = null; //File Access interface * |,N/e  
^ 0YQlT98  
>*{k~Y-G  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException VBL4cU8D  
{ wmGcXBHt$  
this.sURL = sURL; T<0r,  
this.nStartPos = nStart; HQP.7.w7 5  
this.nEndPos = nEnd; Li6|c*K'  
nThreadID = id; =\.*CY|;N  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 xZ`z+
)  
} (-WRZLOQ  
t\ oud{Cv  
I%J>~=]n_  
public void run() z+yq%O  
{ kZG.Id  
while(nStartPos < nEndPos && !bStop) d MR?pbD  
{ v`,!wS  
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!Sn|!:N4  
try{ x\G%  
URL url = new URL(sURL); v%qOW)].  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ! eZls  
httpConnection.setRequestProperty("User-Agent","NetFox"); wU+r]SK@  
String sProperty = "bytes="+nStartPos+"-"; 7G_<+rn  
httpConnection.setRequestProperty("RANGE",sProperty); 8Ij<t{Lps  
Utility.log(sProperty); F~6]I
I  
,5$G0  
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InputStream input = httpConnection.getInputStream(); rByth,|  
//logResponseHead(httpConnection); vIJ5iLF  
JhFn"(O  
-Rw3[4>@O"  
byte[] b = new byte[1024]; '*y(F*7+  
int nRead; j_2g*lQ7a  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) TMMKRC1<  
{ !=:>yWQ  
nStartPos += fileAccessI.write(b,0,nRead); \B4H0f  
//if(nThreadID == 1) id:,\iJ  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); yo#r^iAr  
} ] x)>q  
lV^#[%  
ndLEIqOY  
Utility.log("Thread " + nThreadID + " is over!");  ,RR{Y-  
bDownOver = true; A6=Z2i0w>X  
//nPos = fileAccessI.write (b,0,nRead); |,,#DSe  
} gttsxOgktH  
catch(Exception e){e.printStackTrace ();} h,Hr0^?  
} :o!Kz`J  
} X0 |U?Ib?  
/#Pm'i>B  
"?zWCH  
//打印回应的头信息 zjr($?  
public void logResponseHead(HttpURLConnection con) eV*QUjS~  
{ ="$w8iRU  
for(int i=1;;i++) A.r7 ks  
{ &b#d4p6&l  
String header=con.getHeaderFieldKey(i); U6/7EOW,  
if(header!=null) Jt5V{9:('  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); J`5+Zngr  
Utility.log(header+" : "+con.getHeaderField(header)); ura&9~  
else p"hO6b%V  
break; 0
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} x4v:67_^  
} &)k=ccm  
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nCi ]6;Y  
public void splitterStop() W5Z-s.o  
{ :<P4=P P  
bStop = true; GPHb-  
} Ll=G+cw6P  
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f)_<Ih\/7_  
} LKvX~68  
@LI;q  
L!xFhVA<  
/*  Q(f0S  
**FileAccess.java n3$=&  
*//文件访问(定位，写) d=bKNA90  
package NetFox; KuwhA-IL  
import java.io.*; :

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legWY)4D;  
c-hc.i}!  
public class FileAccessI implements Serializable{ "J,|),Yd  

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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 s;bGg  
RandomAccessFile oSavedFile; AHs%?5YTY;  
long nPos; ,mm97I  
-E\G3/*51  
/rZk^/'  
public FileAccessI() throws IOException 4S'e>:  
{ o`n8Fk}i  
this("",0); P-ZvW<M  
} nX:E(9q7c  
"}_J"%  
 ="]r{  
public FileAccessI(String sName,long nPos) throws IOException .<QKQ%-  
{ sd\}M{U  
oSavedFile = new RandomAccessFile(sName,"rw"); "&SE!3*m`I  
this.nPos = nPos; vx?KenO}  
oSavedFile.seek(nPos); AT I=&O`  
} >
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dE8f?L'  
75H!i$(*+  
public synchronized int write(byte[] b,int nStart,int nLen) <y?+xZM]#|  
{ **m8 HD  
int n = -1; 7Z2D}O+  
try{ w aniCEo  
oSavedFile.write(b,nStart,nLen); m)66g]F+  
n = nLen; Z]Xa:[  
} 4e>f}u5  
catch(IOException e) ?&0CEfa?  
{ FMCA~N  
e.printStackTrace (); o%+w:u.  
} gtH^'vFZ  
U $#^
e  
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return n; ,2!7iX  
} 1.p?1"4\u  
agfDx^,  
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} 5(#z)T  
8-+# !]  
]uhG&: }  
/* $xW9))  
**SiteInfoBean.java xKL(:ePS  
*/ ]u|FcwWc3  
package NetFox; I*U7YqDC9  
!N+{X\+  
#(qvhoi7lM  
public class SiteInfoBean { JUw|nUnl?  
0*]0#2Z  

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private String sSiteURL; //Site's URL )Mq4p'*A[  
private String sFilePath; //Saved File's Path LT{g^g  
private String sFileName; //Saved File's Name X_-/j.  
private int nSplitter; //Count of Splited Downloading File IrRy1][Qr  
"T /$K  
O(evlci  
public SiteInfoBean() N@0/
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{//nSplitter的缺省值为5 c%G~HOE=B  
//default value of nSplitter is 5 rYPuo  
this("","","",5); n.N0Nhd  
} Kc] GE#~g  
r9}(FL/)b  
(~\HizSl  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) _Rjbm'kC  
{ xM)P=y_!M+  
sSiteURL= sURL; @&HLm^j2O  
sFilePath = sPath; zfUj%N  
sFileName = sName; |C./gdq  
this.nSplitter = nSpiltter; 7h/Mkim$5  
d>J +7ex+  
Dp*:oMATx0  
} @QJPcF"  
i`9}">7v~  
&gV9h>Kc#  
public String getSSiteURL() `Q+O#l?  
{ hHMp=8J7  
return sSiteURL; h{yh}04P1  
} *@lVesC2  
CiU^U|~'L  
qu1! KS  
public void setSSiteURL(String value) %A `9[icy  
{ Y"5FK  
sSiteURL = value;  wD  
} \K2S.j  
'yOx&~H]  
#( 4)ps.  
public String getSFilePath() "JF  
{ siuDg,uqK5  
return sFilePath; U>b.MIBX  
} <!W9EM  
vG}\Amx+  
sWA-_4  
public void setSFilePath(String value) jbOwpyH  
{ V:D?i#%,z  
sFilePath = value; ,!AYeVq  
} KdlUa^}
D  
%MtaWZ  
0^P9)<k'  
public String getSFileName() A@.ruG$  
{ ?)qm=mebY  
return sFileName; 0a?[@ -Sz  
} IH=%%AS  
z5^Se!`5  
a#Z#-y!  
public void setSFileName(String value) \ 511?ik  
{ k fOd|-  
sFileName = value; vKbGG  
} :d<F7`k H  
Ov:U3P?%  
7'{%dj
L  
public int getNSplitter() 3gCP?%R  
{ Kv5 !cll5  
return nSplitter; 6XhS g0s  
} -k,}LJj
o  
D#ED?Lqf  
PVq y\i  
public void setNSplitter(int nCount) pkIJbI{aS  
{ (:#4{C  
nSplitter = nCount; 
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} dm83YCdL  
} @`sZV8  
z[+pN:47  
A{eh$Ot%  
/* 7bW''J*6  
**Utility.java dr=KoAIxy  
*/ .GDY J9vi  
package NetFox; DQ6pe)E|  
f,+ONV]5Tt  
(aq^\#9btO  
public class Utility { XKBQH(  
fJ-8$w\uL  
t2-bw6U  
public Utility() xtS0D^  
{ nza^<DlS  
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V+y:!t`  
} }?d l.=eq  
&2Cu"O'.i  
//线程睡眠 JR/^Go$^  
public static void sleep(int nSecond)
SI l<\  
{ _@]@&^K$E  
try{ :e4[isI  
Thread.sleep(nSecond); g5~1uU$O  
} f,0oCBLPO  
catch(Exception e) sv>c)L}I  
{ A$'rT|>se  
e.printStackTrace (); 9TE
-
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} IPh_QE2g  
} (XA]k%45  
h,Tsb:Q"M  
//日志 @ GzN0yXhR  
public static void log(String sMsg) /I' np  
{
*j|BSd P  
System.err.println(sMsg); 8:UV;5@  
} <7
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2fJ2o[v  
O7Awti-X  
public static void log(int sMsg) }qdGS<{  
{ !eB&3J  
System.err.println(sMsg); (AgM7H0  
} gcs8Gl2  
} D\GP+Ota  
FBK6{rLMc  
%xI,A'#  
/* `Df)wNN1  
**TestMethod.java ~%:23mIk  
*/ Dadl
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package NetFox; ZTSNM)f  
\c$!C8z  
]2B=@V t,  
public class TestMethod { E2{SKIUm  
faaFmEC  
v.I>B3bEg  
public TestMethod() lo!_;`v=U  
{ ///xx/weblogic60b2_win.exe fDY#&EO: %  
try{  ^'c[HVJ  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Ke+#ww  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); \lpR+zaF  
SiteFileFetch fileFetch = new SiteFileFetch(bean); N)Z,/w9  
fileFetch.start(); k@ZmI^  
} cw{[% 7  
catch(Exception e){e.printStackTrace ();} 6~0.YZ9  
/\M3O  
k GzosUt  
} :Keek-E`e=  
!pLQRnI}6  
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public static void main(String[] args) x5}Ru0Z  
{ m48m5>  
new TestMethod(); 5*pCb,z>q  
} J$D#)w!$j  
} QR($KW(  
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