http断点续传简单实现（java)

/* *h=>*t?I2  
**SiteFileFetch.java t+q;}ZvG  
*/ 0!KYi_3  
package NetFox; MEJX5qG6m  
import java.io.*; %.]#3tW  
import java.net.*; tg==Qgz  
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]4V1]  
public class SiteFileFetch extends Thread { 9E8&~y  
`?WN*__["  
`Mbs6AJ  
SiteInfoBean siteInfoBean = null; //文件信息Bean 0sH~yvM5  
long[] nStartPos; //开始位置 |HYST`  
long[] nEndPos; //结束位置 %6rSLBw3  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 V9qA'k  
long nFileLength; //文件长度 Oq,@{V@)9k  
boolean bFirst = true; //是否第一次取文件 >;Vfs{Z(q  
boolean bStop = false; //停止标志 &7>]# *  
File tmpFile; //文件下载的临时信息 *| W*Mu  
DataOutputStream output; //输出到文件的输出流 +F8K%.Q_  
kaiK1/W0;  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） /\uop
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public SiteFileFetch(SiteInfoBean bean) throws IOException 'UxI-Lt  
{ /Z!$bD  
siteInfoBean = bean; 5/i/. 0?n  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 0bc>yZ\R  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); "+Ys}t~2  
if(tmpFile.exists ()) _u u&?<h  
{ 3N+B|WrM  
bFirst = false; j[FB*L1!D  
read_nPos(); Q_!tn*  
} 2#3`[+g<n  
else nTD%i~t~o  
{ MMC$c=4"  
nStartPos = new long[bean.getNSplitter()]; QA;,/iw`  
nEndPos = new long[bean.getNSplitter()]; S5, u| H  
} ebNRZJ?C,  
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} k\;D;e{  
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public void run() Mp!1xx  
{ aXQAm$/ >  
//获得文件长度 '0)`.  
//分割文件 3)LS#=  
//实例FileSplitterFetch a9.255  
//启动FileSplitterFetch线程 [g<gu~  
//等待子线程返回 ;<''oY  
try{ rP2h9Cb  
if(bFirst) X[H.t$w5A  
{ 7-n HP
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nFileLength = getFileSize(); V9}\0joM  
if(nFileLength == -1) eq8faC5  
{ km5gO|V>m  
System.err.println("File Length is not known!"); SqRM*Cf=  
} 8v8-5N  
else if(nFileLength == -2) -!qjBK,`X  
{ NIQ}+xpC  
System.err.println("File is not access!"); ZsXw]Wa  
} ("j;VqYUL  
else ":qHDL3  
{ <T)0I1S  
for(int i=0;i<nStartPos.length;i++) E'D16Rhp  
{ &{glwVKV  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Qbjm,>H/^  
} 1y6<gptx  
for(int i=0;i<nEndPos.length-1;i++) htL1aQ.  
{ )4s7,R  
nEndPos = nStartPos[i+1]; !v=/f_6  
} @&&}J  
nEndPos[nEndPos.length-1] = nFileLength; !\d~9H%`B  
} ^>!&]@  
} *S}CiwW>/  
)m8Gbkj<  
ar,v/l>d4N  
//启动子线程 SFtcO  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; (G} }h  
for(int i=0;i<nStartPos.length;i++) l<4P">M!.  
{ N}NKQ]=  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), a?GXVQ  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), &Z!y>k%6
 
nStartPos,nEndPos,i); yih|6sd$F  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 2Og5e  
fileSplitterFetch.start(); ,xrA2  
} cT@| $A  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), >eo[)Y  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ||TZ[l  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ):Z#!O<  
nEndPos = " + nFileLength); dZf1iFCP  
// fileSplitterFetch[nPos.length-1].start(); bc~WJ+  
pV(Mh[ }P  
YU+P+m2X  
//等待子线程结束 N#RC;  
//int count = 0; 1,$"'lKwt  
//是否结束while循环 X[$|I9  
boolean breakWhile = false; :OjmaP
 
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8rlf9m  
while(!bStop) Ja5od  
{ -}j(_]t  
write_nPos(); )p;t '
*]  
Utility.sleep(500); 8EdaqF  
breakWhile = true; [bX^_ Y  
dyf>T}Iy  
FW;}S9u3  
for(int i=0;i<nStartPos.length;i++) -:'%YHxX  
{ SB('Nqih  
if(!fileSplitterFetch.bDownOver) 6)ZaK  
{ 0F_hXy@K  
breakWhile = false; sKKc_H3YSH  
break; fH_l2b[-3@  
} ;r6YIS4@  
} q2
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if(breakWhile) `EvO^L  
break; <o3I<ci6  
FJ!`[.t1AU  
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//count++; !T:7xEr  
//if(count>4) 4Y3@^8h&=  
// siteStop(); xhho{  
} q&&"8.w-  
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o$%KbfXO]  
System.err.println("文件下载结束！"); TNN@G~@cm  
} AX6:*aZB  
catch(Exception e){e.printStackTrace ();} K8-1?-W  
} R1Q,
m  
5Rw2/J L  
e:4,rfF1  
//获得文件长度 Y?0x/2<  
public long getFileSize() JBOU$A~  
{ Lk$Mfm5"M  
int nFileLength = -1; /g9^g(  
try{ R)$]r>YZF  
URL url = new URL(siteInfoBean.getSSiteURL()); $6 Hf[(/e  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); t.RDS2N|  
httpConnection.setRequestProperty("User-Agent","NetFox"); c2
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,  
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int responseCode=httpConnection.getResponseCode(); 3$K[(>s  
if(responseCode>=400) [okV[7  
{ Kx,X{$Pe  
processErrorCode(responseCode); sm G?y
~  
return -2; //-2 represent access is error TxN+-< f  
} WL'!M&h  
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String sHeader; <jYyA]Zy5  
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for(int i=1;;i++) QqW N7y_9  
{ + `'wY?  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); CK4#ZOiaa  
//Utility.log(in.readLine()); ]goVQ'Y  
sHeader=httpConnection.getHeaderFieldKey(i); 8p}z~\J{a:  
if(sHeader!=null) =s'H o  
{ {|<r7K1<  
if(sHeader.equals("Content-Length")) 7.2!g}E  
{ "7Kw]8mRR  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); &"T7KXx  
break; \SwqBw  
} YKayaI\*  
} o.|36#Fa  
else o>d0R w4h  
break; b%@9j;  
} N.E{6_{S  
} MZA%ET,l,<  
catch(IOException e){e.printStackTrace ();} Y:Lkh>S1Q  
catch(Exception e){e.printStackTrace ();} *>W6,F7  
H>]*<2(=-  
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Utility.log(nFileLength); ?;5/"/i  
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return nFileLength; =)i^E9
 
}
|FlB#  
RhF<{U.  
u|"YS-dH  
//保存下载信息（文件指针位置） `O.pT{Lf  
private void write_nPos() ND=JpVkvZ?  
{ F &5iA\  
try{ aYpc\jJ  
output = new DataOutputStream(new FileOutputStream(tmpFile)); C9k"QPE  
output.writeInt(nStartPos.length); _Fv6S}~Q  
for(int i=0;i<nStartPos.length;i++) Oo(xYy  
{ 4
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// output.writeLong(nPos); J?Q@f  
output.writeLong(fileSplitterFetch.nStartPos); ]0%{IgB  
output.writeLong(fileSplitterFetch.nEndPos); }waZGJLN  
} ^Dfqc-]  
output.close(); K~^o06 Y  
} LSXsq}  
catch(IOException e){e.printStackTrace ();} p`U#  
catch(Exception e){e.printStackTrace ();} ~fcC+"7q/  
} lY,9bSF$  
Vz!{nL0Q(  
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//读取保存的下载信息（文件指针位置） I7|a,Q^f  
private void read_nPos() ev/)#i#s{  
{ R&P^rrC@B5  
try{ ?aTC+\=  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Jzy:^PObT  
int nCount = input.readInt(); $SFreyI;Uf  
nStartPos = new long[nCount]; ]eFNR1<OP  
nEndPos = new long[nCount]; #zSNDv`  
for(int i=0;i<nStartPos.length;i++) h.- o$+Sa  
{ 0CX9tr2J  
nStartPos = input.readLong(); r"x}=# b!  
nEndPos = input.readLong(); -(%Xq{  
} >oEFuwE  
input.close(); 7VkjnG^!:  
} 6BQq|:U  
catch(IOException e){e.printStackTrace ();} YCzH@94QeV  
catch(Exception e){e.printStackTrace ();} |Df`Aq(eYJ  
} mc,HliiJ  
,L>{(Q)  
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private void processErrorCode(int nErrorCode) XC/M:2$  
{ 6B>*v`T:  
System.err.println("Error Code : " + nErrorCode); NJoHrhC='  
} QOJ5  
OMYbCy^  
NW21{}=4  
//停止文件下载 )B~{G\jS  
public void siteStop() }>YEtA  
{ ^QHgc_oDm  
bStop = true; K3rsew n  
for(int i=0;i<nStartPos.length;i++) 6BXZGE  
fileSplitterFetch.splitterStop(); mwz!7Q   
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yB;K|MXy?  
} '=K~M  
} "Nq5FcS9  
//负责部分文件的抓取 biQ~q$E  
**FileSplitterFetch.java nvodP"iV  
*/ _71I9V&  
package NetFox; w>RwEU+w=@  
>7W8_6sC<  
Gh%dVP9B@P  
import java.io.*; 8<EU|/O  
import java.net.*; :FS~T[C;  
d,j)JnY3V  
ukD:4sv  
public class FileSplitterFetch extends Thread { 2Aa  
W7T2j+]  
`j.-hy>s  
String sURL; //File URL .^rsVNG  
long nStartPos; //File Snippet Start Position =`V9{$i  
long nEndPos; //File Snippet End Position S^i<_?nwg  
int nThreadID; //Thread's ID v:9Vp{)  
boolean bDownOver = false; //Downing is over MP Q?Q]'  
boolean bStop = false; //Stop identical 5'(#Sf
 
FileAccessI fileAccessI = null; //File Access interface ET6}V"UD  
3|/zlKZz  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException <2I<Z'B,e  
{ 0{Zwg0&  
this.sURL = sURL; = o1&.v2j  
this.nStartPos = nStart; VK}H;  
this.nEndPos = nEnd; :+fW#:  
nThreadID = id; uH)v\Js  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ;,B $lgF  
} 0qN?4h)7  
yfAh=  
h61BIc@>  
public void run() !T]bz+  
{ ~llw_w  
while(nStartPos < nEndPos && !bStop) jrYA5>=>#  
{ 0IbR>zFg.  
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try{ 0'`#I  
URL url = new URL(sURL); nh"LdHqiDB  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); %#lJn.o  
httpConnection.setRequestProperty("User-Agent","NetFox"); F @Wb<+0  
String sProperty = "bytes="+nStartPos+"-"; il:RE8  
httpConnection.setRequestProperty("RANGE",sProperty); vH?3UW  
Utility.log(sProperty); CX>QP&Gj  
<gY.2#6C\%  
nqib`U@"  
InputStream input = httpConnection.getInputStream(); (n@&M!a  
//logResponseHead(httpConnection); FWpb5jc)3  
0"c(n0L  
;5aAnvgW  
byte[] b = new byte[1024]; +[=%
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int nRead; {gS7pY%_W  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ? y^t  
{ 4Mjcx.21  
nStartPos += fileAccessI.write(b,0,nRead); p+{*&Hm5  
//if(nThreadID == 1) g; ZVoD  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); m<:g\_<  
} J|WkPv2  
~5_>$7L>  
}& e#b]&:*  
Utility.log("Thread " + nThreadID + " is over!"); (d=knoo7A  
bDownOver = true; t1]svVX,w  
//nPos = fileAccessI.write (b,0,nRead); ?Ns aZ  
} uhr&P4EW  
catch(Exception e){e.printStackTrace ();} t|k-Bh:x  
} 2?9gf,U  
} 9$N~OZ;-*x  
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//打印回应的头信息 1n+JHXR\  
public void logResponseHead(HttpURLConnection con) tc)4$"9)  
{ VrZ6m  
for(int i=1;;i++) ?C|b>wM/  
{ ?h|w7/9  
String header=con.getHeaderFieldKey(i); gn4Sz")  
if(header!=null) N51RBA  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 3*[YM7y  
Utility.log(header+" : "+con.getHeaderField(header)); K<D=QweOon  
else EN@
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break; Kd^,NAg  
} G\o*j|  
} ZklZU,\!|v  
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public void splitterStop() v.e~m2u_F  
{ UhF+},gU  
bStop = true; =%G<S'2'  
} )|i]"8I  
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Kx5VR4f`J@  
} W .bJ.hO*  
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/* ugMfpT)  
**FileAccess.java 81/t)Cp  
*//文件访问(定位，写) %DF-;M"8  
package NetFox; C\C*'l6d  
import java.io.*; M}b[;/~  
d"hW45L  
jMB&(r  
public class FileAccessI implements Serializable{ !&8HA   
2ID]it\5  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 #MI4 `FZ  
RandomAccessFile oSavedFile; IAa}F!6Q1  
long nPos; !S}4b  
J+20]jI  
o+.LG($+U  
public FileAccessI() throws IOException v6_fF5N/  
{ 9)]asY  
this("",0); ~xP4}gs1  
} j5qrM_Chg  
S2EeC&-AR  
vB9v
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public FileAccessI(String sName,long nPos) throws IOException }O7b&G:nW  
{ *1clPK  
oSavedFile = new RandomAccessFile(sName,"rw"); mk&`dr  
this.nPos = nPos; 8 ,<F102(  
oSavedFile.seek(nPos); ;Jq7E  
} c2fbqM~  
,Z6\%:/  
@{y[2M} %]  
public synchronized int write(byte[] b,int nStart,int nLen) ley:=(  
{ is [p7-  
int n = -1; A5LTgGzaW  
try{ g4 G?hv`R  
oSavedFile.write(b,nStart,nLen); C N
t  
n = nLen; @u}1
S1  
} Xeo2 < @[  
catch(IOException e) 'WLh D<  
{ A ^wIsAxT  
e.printStackTrace (); c$[cDf~  
} &e~g}7  
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,8MUTXd@ V  
return n; c O[
Hr  
} (lBwkQNQGd  
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%uWq)D4r  
} !uJDhC  
Q(J6;s#b  
8KU5x#  
/* ZdjmZx%
%  
**SiteInfoBean.java b/eJEL  
*/  wN4N2  
package NetFox; XFU['BI  
 "0( _  
20XN5dTFT  
public class SiteInfoBean { Z_qOQ%l  
a*gzVE7W#n  
@3F4Lg6H|  
private String sSiteURL; //Site's URL -l#h^  
private String sFilePath; //Saved File's Path a J&)-ge  
private String sFileName; //Saved File's Name vUU)zZB~  
private int nSplitter; //Count of Splited Downloading File @L ,hA v^  
4)XZ'~|  
SZ[,(h  
public SiteInfoBean() Fs,#d%4@%  
{//nSplitter的缺省值为5 &n)=OConge  
//default value of nSplitter is 5 ^YLk
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this("","","",5); VS{po:]A  
} .+ w#n<  
|6d0,muN  
R;68C6 4  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) U:n3V  
{ KPcOW#.T  
sSiteURL= sURL; e MT5bn  
sFilePath = sPath; @!UuK;  
sFileName = sName; ]a}K%D)H  
this.nSplitter = nSpiltter; ,XJ Xw(LM  
*$eMM*4  
sD[G?X  
} Fuuy_+p@G  
W"a%IO%'  
 @{|vW  
public String getSSiteURL() lSu\VCG  
{ B]o5HA<k  
return sSiteURL; 2#y!(D8  
} V"T48~Ue  
j(|9>J*,~G  
I#m0n%-[  
public void setSSiteURL(String value)  XAb!hc   
{ >)sB#<e  
sSiteURL = value; TzJp3  
} 9J0JSy  
dfss_}R  
4._U  
public String getSFilePath() pW>?%ft.  
{ cR0OJ'w  
return sFilePath; *)6:yn  
} O~1vX9  
).BZPyV<  
~$O.KF
:  
public void setSFilePath(String value) #:yh2y7a%  
{ 2!u4nxZ.  
sFilePath = value; wInJ!1  
} ,a&&y0,  
/kLG/ry8l:  
#H;yXsR`  
public String getSFileName()
y]5c!N %8  
{ j6NK7Li  
return sFileName; 9 ^G.]W]  
} GjmPpKIu\  
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public void setSFileName(String value) 2th>+M~A  
{ M:4N'
#`  
sFileName = value; NZ}DbA+g;|  
} =%O@%v  
hd@ >p.  
^`96
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public int getNSplitter() 8N8N)#A[  
{ n%M-L[n  
return nSplitter; {Gd<+tQg  
} _qZ?|;o^  
HFr#Ql>g  
-/k;VT|  
public void setNSplitter(int nCount) ]~!jf  
{ yO7xAb  
nSplitter = nCount; )_vE"ryThA  
} m3cO{ 1I  
} 23F<f+2S  
01 vEt  
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/* /qYo*S_cG  
**Utility.java w;RG*rv  
*/ \sUk71L`j  
package NetFox; -t<8)9q(  
O[tOpf@s.  
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public class Utility { Vh.9/$xQ  
^X&n-ui   
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public Utility() [%8t~zg  
{ 0nh;0Z  
UJqDZIvC  
vbDSNm#Yv  
} +, SUJ|  
9vAY|b^  
//线程睡眠 @435K'!  
public static void sleep(int nSecond) 4!Cu>8B  
{ L=7U#Q/DE  
try{ X"S-f;b#  
Thread.sleep(nSecond); jK[~dY
  
} .3{PgrZ  
catch(Exception e) #~ :j< =o  
{ 9WJS.\G^  
e.printStackTrace (); DPU%4te  
} i|@lUXBp  
} )CYm
/dk  
)4[Yplo  
//日志 U_-9rkUa  
public static void log(String sMsg) Yt 9{:+[RK  
{ @+gr>a1K#  
System.err.println(sMsg); RS$!
TTeQ  
} [@l:C\2  
^[7ZBmS  
^x! N]  
public static void log(int sMsg) jkPye{j  
{ Q\P?[i]  
System.err.println(sMsg); @E(_H$|E  
} (5^bU<  
} 6vx0F?>_  
Hcp)Q76X  
ZQZBap"  
/* Po%+:0oX  
**TestMethod.java @_gCGI>Q  
*/ >O{U4_j@(  
package NetFox; r[>=iim  
i|z=q  
m.F \Mn  
public class TestMethod { ZB+N[VJs)  
ST#OO!  
;3nR_6\  
public TestMethod() q'07  
{ ///xx/weblogic60b2_win.exe )zFPf]gz  
try{ &8l"Dl  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); n/ \{}9  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ,qx;
kJJ  
SiteFileFetch fileFetch = new SiteFileFetch(bean); B,@<60u  
fileFetch.start(); _TB,2 R  
} _K4Igq  
catch(Exception e){e.printStackTrace ();} d)G'y  
JGJXV
3AT  
=F(fum;zH  
} qjK'sge/  
eV?._-G  
i2a""zac  
public static void main(String[] args) D{Zjo)&tF'  
{ 0Zt=1Tv  
new TestMethod(); >S3,_@C  
} G_fP%ovh  
} Dr;-2$Kt/&  
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