http断点续传简单实现（java)

/* 4j=3'Z|  
**SiteFileFetch.java >`0U2K  
*/ RG{T\9]n  
package NetFox; zuLW'a6F-
 
import java.io.*; K khuPBd2  
import java.net.*; rNq*z,  
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public class SiteFileFetch extends Thread { ZU`9]7"87B  
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SiteInfoBean siteInfoBean = null; //文件信息Bean _=~u\$  
long[] nStartPos; //开始位置 p[C"K0>:_F  
long[] nEndPos; //结束位置 P:'wSE91  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 D!~ Y"4<  
long nFileLength; //文件长度 btuG%D{a^  
boolean bFirst = true; //是否第一次取文件 Bib<ySCre  
boolean bStop = false; //停止标志 i]r(VKX  
File tmpFile; //文件下载的临时信息 )$:1e)d  
DataOutputStream output; //输出到文件的输出流 eLSzGbKf  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） G$>?UQ[  
public SiteFileFetch(SiteInfoBean bean) throws IOException !:|*!  
{ ?gMx  
siteInfoBean = bean; G1z*e.+y  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Xj\ToO  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 23):OB>S`  
if(tmpFile.exists ()) !G3AD3  
{ ,GH`tK_  
bFirst = false; b]]
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read_nPos(); J#..xJ?XRD  
} fs ufYIf  
else 8:{id>Mm^  
{ '(5GRI<  
nStartPos = new long[bean.getNSplitter()]; v8ap"9b  
nEndPos = new long[bean.getNSplitter()]; lD,2])>  
} -'$ob~*  
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} b)I-do+  
r
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public void run() `DY yK?R  
{ ,s~l; Gkj  
//获得文件长度 Q~(Gll;  
//分割文件 bgorW"'  
//实例FileSplitterFetch r"d
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//启动FileSplitterFetch线程 ]W5*R07
 
//等待子线程返回 UTkPA2x  
try{ LU:xmDv  
if(bFirst) |'?vlUCd  
{ `NW/Z/_  
nFileLength = getFileSize(); N[/<xW~x?4  
if(nFileLength == -1) >s^$-  
{ /]`@.mZ9:  
System.err.println("File Length is not known!"); U+!RIF[Je  
} q}P@}TE  
else if(nFileLength == -2) %l7[eZ{Y  
{ J9mK9{#q  
System.err.println("File is not access!"); <T_3s\  
} *C*ZmC5  
else n-ffX*zA(  
{ RM|J |R  
for(int i=0;i<nStartPos.length;i++) tY)L^.*7  
{ ~qgh
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); +5zXbfO  
} g
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for(int i=0;i<nEndPos.length-1;i++) Nj>6TD81u  
{ (TT=i  
nEndPos = nStartPos[i+1]; ]rlZP1".  
} hObL=^F  
nEndPos[nEndPos.length-1] = nFileLength; &42]#B"*  
} Ooz,?wU6  
} .
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*kLFs|U  
/L^g. ~  
//启动子线程 b&rBWp0#  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; G WIsT\J  
for(int i=0;i<nStartPos.length;i++) ;b{#$#`=  
{ zq};{~u(  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), rwq   
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), P=n_wE  
nStartPos,nEndPos,i); Yqs=jTq`{  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); c<$<n  
fileSplitterFetch.start(); z&%i
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} m# {'9 |  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), '8
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); r{R-X3s
 
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", P~\rP6 ;  
nEndPos = " + nFileLength); MRLiiIrq,5  
// fileSplitterFetch[nPos.length-1].start(); X"{%,]sb G  
:'p)xw4K|  
*O_fw 0jV  
//等待子线程结束 *$eH3nn6g  
//int count = 0; _w\9 \<%  
//是否结束while循环 6eSo.@*l  
boolean breakWhile = false; SxRJ{m~  
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while(!bStop) ZsP^<  
{ gQ\.|'%  
write_nPos(); GeR#B;{  
Utility.sleep(500); xvTtA61Vp  
breakWhile = true; Z@Rm^g]o  
KR?;7*qF  
(K[{X0T  
for(int i=0;i<nStartPos.length;i++) 9<Pg2#*N0  
{ ^N={4'G)  
if(!fileSplitterFetch.bDownOver) =!\Nh,\eQ  
{ xTAfVN  
breakWhile = false; %%NoXW  
break; );0  
} 9kD#'BxC  
} 8T3,56>  
if(breakWhile) ^)dsi  
break; >+%#m'Y&&  
~wa4kS<>  
8:TX9`,  
//count++; 7:UeE~uB:  
//if(count>4) x$LCLP#$H  
// siteStop(); }3*<sxw7<  
} Bq8#'K2i
,  
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V(&L  
System.err.println("文件下载结束！"); *u$aItx  
} Dmh$@Uu#F  
catch(Exception e){e.printStackTrace ();} 1mmL`M1  
} eHgr"f*7   
CF;Gy L1M  
r)t[QoD1  
//获得文件长度 qR@ESJ_  
public long getFileSize() Lvf<g}?4  
{ E^-c
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int nFileLength = -1; "uBnK!  
try{ Oa/^A-'Q  
URL url = new URL(siteInfoBean.getSSiteURL()); +p\E%<uQ
 
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ;?Pz0,{h  
httpConnection.setRequestProperty("User-Agent","NetFox"); >|SIqB<%:  
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int responseCode=httpConnection.getResponseCode(); 8>C4w 5kF  
if(responseCode>=400) B /;(#{U;  
{ v^&HZk=(  
processErrorCode(responseCode); tiZH;t';<  
return -2; //-2 represent access is error =IL\T8y09  
}  7UBDd1  
u#ya 8  
#*A&jo'E  
String sHeader; Mq91HmC(@  
&E`Nu (e  
b~^'
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for(int i=1;;i++) !td!">r46e  
{ :I#.d7`uk  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ^(;x-d3  
//Utility.log(in.readLine()); V[.{cY?6  
sHeader=httpConnection.getHeaderFieldKey(i); SWdmej[  
if(sHeader!=null) t=7Gfv
 
{ UuIjtqW  
if(sHeader.equals("Content-Length"))  9tpyrGv  
{ C1-U2@  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); :-x?g2MY  
break; 5X0ex.  
} &eV5#Ph  
} ["nWIs[h  
else !{l% 3'2  
break; ?c8~VQaQ  
} dC6>&@ VX  
} I!/EQO|  
catch(IOException e){e.printStackTrace ();} %E%=Za  
catch(Exception e){e.printStackTrace ();} 9':Ipf&x  
G!F
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Utility.log(nFileLength); (%R%UkwP9  
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return nFileLength; F>.y>h  
} v o:KL%)  
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//保存下载信息（文件指针位置） JlSqTfA  
private void write_nPos() yD<#Q\,  
{ t3$cX_  
try{ 6@|!m'  
output = new DataOutputStream(new FileOutputStream(tmpFile)); >.
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output.writeInt(nStartPos.length); T]0K4dp+  
for(int i=0;i<nStartPos.length;i++) Uv59 XF$  
{ M.
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// output.writeLong(nPos); IEm?'o:  
output.writeLong(fileSplitterFetch.nStartPos); u/W{JPlL  
output.writeLong(fileSplitterFetch.nEndPos); %ZRv+}z  
} Z*Ffdh>*:&  
output.close(); G:e=9qTf  
} yl>^QMmo  
catch(IOException e){e.printStackTrace ();} 3JD62wtx  
catch(Exception e){e.printStackTrace ();} ;*5z&1O  
}
1 k!gR  
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6`9QGi,)  
//读取保存的下载信息（文件指针位置） pRfKlTU\  
private void read_nPos() k[mp(  
{ Z(:\Vj"  
try{ 5JOfJ$(n  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); l4kqz.Z-g  
int nCount = input.readInt(); L@MCB-@V  
nStartPos = new long[nCount]; lsV>sW4]Z  
nEndPos = new long[nCount]; uhq6dhhR  
for(int i=0;i<nStartPos.length;i++) 9ZOQNN<ex  
{ 7'+`vt#E  
nStartPos = input.readLong(); kYS#P(1  
nEndPos = input.readLong(); h6~xz0,u  
} =)y$&Ydj  
input.close(); T \34<+n1N  
} d)48m}[:  
catch(IOException e){e.printStackTrace ();} (l][_6Q  
catch(Exception e){e.printStackTrace ();} .NdsKhg b  
} ]oix))'n  
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wPghgjF{  
private void processErrorCode(int nErrorCode) 8k{XUn  
{ ?o V.SG'  
System.err.println("Error Code : " + nErrorCode); fe4/[S{a   
} Tx?s?DwC  
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O  
{{A=^rr%C  
//停止文件下载 `
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public void siteStop() :V8oWMY  
{ pz2E+o  
bStop = true; }Bh\N5G%  
for(int i=0;i<nStartPos.length;i++) =YYqgNz+\w  
fileSplitterFetch.splitterStop(); 2s2KI=6  
(q"S0{  
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} je\]j-0$u  
} "=?JIQ  
//负责部分文件的抓取 e>Q:j_?.e  
**FileSplitterFetch.java v'L"sgW6I  
*/ jhG6,;1zMI  
package NetFox; GLY,
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import java.io.*; 3Mh_&%
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import java.net.*; BI2'NN\  
[e=k<gKH  
a&)$s;
  
public class FileSplitterFetch extends Thread { !G;BYr>X  
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6#d+BBKIc  
String sURL; //File URL e,vgD kI;  
long nStartPos; //File Snippet Start Position <O9WCl  
long nEndPos; //File Snippet End Position cL%eP.  
int nThreadID; //Thread's ID _uh@fRyh  
boolean bDownOver = false; //Downing is over @zR_[s  
boolean bStop = false; //Stop identical w#(E+s~}  
FileAccessI fileAccessI = null; //File Access interface 9MRe?  
oz'jt} ?  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException N}bZdE9F  
{ g[2[ zIB=  
this.sURL = sURL; "=f,4Zbj  
this.nStartPos = nStart; 7<Ut/1$MI  
this.nEndPos = nEnd; |b Z 58{}  
nThreadID = id; H_JT"~_2  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 }LBrk0]  
} ~}YgZ/U7T  
"(F:'J} X  
=Oh/4TbW[  
public void run() o,1Fzdh6(  
{ uN9.U  _  
while(nStartPos < nEndPos && !bStop) (>D{"}  
{ IOUzj{G#  
#"-w;T%b  
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try{ ;hDIo
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URL url = new URL(sURL); $>~4RXC  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 9OF(UFgS  
httpConnection.setRequestProperty("User-Agent","NetFox"); (j}Wt8  
String sProperty = "bytes="+nStartPos+"-"; Y%rC\Ij/i  
httpConnection.setRequestProperty("RANGE",sProperty); =>C3IR/  
Utility.log(sProperty); ~xZ)b
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am WIA`n=  
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InputStream input = httpConnection.getInputStream(); 0w^awT<$6  
//logResponseHead(httpConnection); +fF4]WFP  
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byte[] b = new byte[1024]; .9bP8u2B{  
int nRead; ]s_BOt  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Cvs4dd%)i  
{ Xo4K!U>TzZ  
nStartPos += fileAccessI.write(b,0,nRead); fl9J  
//if(nThreadID == 1) ;#D:S6 L  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); %}~Ncn_r  
} `_e1LEH  
$uNYus^vS  
W$Z""
 
Utility.log("Thread " + nThreadID + " is over!"); ?6^KY+ 5`C  
bDownOver = true; zQ eXN7$  
//nPos = fileAccessI.write (b,0,nRead); -/qu."9(B  
} $ "^yoL  
catch(Exception e){e.printStackTrace ();} rUF= uO(  
} Y'LIk Q\  
}
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7+p=4i^@Zs  
//打印回应的头信息 l3/?,xn  
public void logResponseHead(HttpURLConnection con) 9s6d+HhM  
{ c/}bx52>u  
for(int i=1;;i++) *}i.,4+y   
{ ;lb@o,R :  
String header=con.getHeaderFieldKey(i); cbA90 8@s  
if(header!=null) 8-R; &  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); D(S^g+rd  
Utility.log(header+" : "+con.getHeaderField(header)); *$7c||J7  
else B8G1 #V_jK  
break; mm<rdo(`  
} T%:W6fH7  
} <N;HB&mr  
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public void splitterStop() Y_&)>;  
{ G&*2h2,]  
bStop = true; uod&'g{N  
} {#1}YGpiVM  
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} n.xW"omN  
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!n/"39KT  
/* S(*SUH  
**FileAccess.java Q<pL5[00fD  
*//文件访问(定位，写) 6j
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package NetFox; &P{[22dQ  
import java.io.*; 5Y97?n+6  
:>g*!hpb  
DPZG_{3D  
public class FileAccessI implements Serializable{ B[O1^jdO  
) >SU J^u  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 {)0"?$C_H  
RandomAccessFile oSavedFile; !_gHIJiq}  
long nPos; ZjXpMx,  
3v%V\kO=F  
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public FileAccessI() throws IOException wGf SVA-q\  
{ _6 |lw&o07  
this("",0); LY^pmak  
} Hh8)d/D  
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v [ 4J0  
public FileAccessI(String sName,long nPos) throws IOException /uzU]3KF~  
{ V}kZowWD  
oSavedFile = new RandomAccessFile(sName,"rw"); G? "6[w/p  
this.nPos = nPos; 0xM\+R~,  
oSavedFile.seek(nPos); 0"L_0 t:  
} #}W^d^-5t5  
=X11x)]F9  
RscU=oaKi  
public synchronized int write(byte[] b,int nStart,int nLen) \Z^YaKj&  
{ Q_F8u!qrZ  
int n = -1; Q=%1@ ,x"  
try{ ~sSlfQWMzy  
oSavedFile.write(b,nStart,nLen); 0ZXG{Gp9S  
n = nLen; tPHDnh^n]  
} \]W*0t>s  
catch(IOException e) C<\|4ER
p  
{ G_~w0r#  
e.printStackTrace (); g3(fhfR'RN  
} x%JtI'sg  
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return n; h+!Ld^'c  
} :YU_ \EV  
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} w"O^CR)  
/bj D*rj  
K -!YD}OF  
/* XOzd{  
**SiteInfoBean.java S&% GB  
*/ VSCOuNSc  
package NetFox; nTweQ  
#s)Wzv%OX  
LuB-9[^<  
public class SiteInfoBean { /,z4tf  
R*D0A@  
61q:nWs  
private String sSiteURL; //Site's URL gjJ?*N[  
private String sFilePath; //Saved File's Path <3iL5}  
private String sFileName; //Saved File's Name #$QC2;/)F  
private int nSplitter; //Count of Splited Downloading File ;5A  
< 6[XE  

lUd/^u`  
public SiteInfoBean() u|.L73<j%  
{//nSplitter的缺省值为5 wPYz&&W  
//default value of nSplitter is 5 t%wC~1  
this("","","",5); `Li3=!V[  
} G-[fz  
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{(i>$RG_  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) +v3@WdLcD  
{ :e5)Q=lX  
sSiteURL= sURL; N*N@wJy:5  
sFilePath = sPath; @JS O=8  
sFileName = sName; W~J@v@..4  
this.nSplitter = nSpiltter; ON|Bpt2Qp  
: uglv6
 
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} y-gSal  
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public String getSSiteURL() oO-kO!59y  
{ %l!Gt"\xm  
return sSiteURL; f:gXXigY,  
} xioL6^(Qk,  
"MD  
UUGwXq96i  
public void setSSiteURL(String value) sXdNlR&  
{ -
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sSiteURL = value; ][1*.7-  
} 445}Yw5;9  
=#||&1U$  
Q<.847 )  
public String getSFilePath() 2XubM+6  
{ 8r7~ >p~  
return sFilePath; h\ema|  
} 5"=qVmT)  
|-l)$i@  
%Ji@\|Zkf  
public void setSFilePath(String value) 8|uFW7Q  
{ ^T83E}  
sFilePath = value; vq|o}6Et  
} T> cvV  
^fT|Wm<  
&o>ctf.x  
public String getSFileName() *Y'@|xf*  
{ JyY-@GF  
return sFileName; TQyi-Dc  
} M}E0Msq_o  
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SR@yG:~  
public void setSFileName(String value) 8y5iT?.~vy  
{ 2`qO'V3Q  
sFileName = value; Zb<IZ)i#1  
} |X/
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,b2YUb]U  
t(YrF,  
public int getNSplitter() j^ VAA\  
{ _zq"<Q c  
return nSplitter; u/3[6MIp  
} kZXsL
 
s*<\mwB  
8C1 'g7A<  
public void setNSplitter(int nCount) RM8p[lfX  
{ ]03+8#J  
nSplitter = nCount; j3`#v3  
} Gj^JpG  
} eHUr!zH:  
\^O#)&5 V  
WVUa:_5{  
/* c+:LDc3!Gb  
**Utility.java m%Ah]x;  
*/ AsyJDt'i  
package NetFox; B -XM(Cj  
+.gM"JV  
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3_  
public class Utility { TxL;qZRY ^  
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}!=}g|z#|  
public Utility() qP6YnJWl  
{ q 65mR!)  
"L'
0"  
\8v{9Yb  
} &VG|*&M  
0Q^ -d+!  
//线程睡眠 dLb9p"EE#  
public static void sleep(int nSecond) \mRRx#-r%  
{ n]$50_@  
try{ nA:\G":\y  
Thread.sleep(nSecond); GRV#f06  
} 0?hJ!IT;q7  
catch(Exception e) =\;yxl
 
{ Q@B--Omfh  
e.printStackTrace (); 9aYDi)  
} FV>j !>Y  
} am
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y5;l?v94  
//日志 $2u^z=`b!%  
public static void log(String sMsg) HPT{83  
{ i[obQx S94  
System.err.println(sMsg); U40adP? a  
} Jj=0{(X  
[C)JI;\  
,MkldCV  
public static void log(int sMsg) 6q^Tq {I  
{ ]
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System.err.println(sMsg); @]$qJFXx  
} "vVL52HwB  
} :2#8\7IU^'  
r83chR9  
Q"
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/* ^6*LuXPv  
**TestMethod.java $6\-8zNk  
*/ ;4DqtR"7Y  
package NetFox; 6- H81y3  
V\k?$}  
oNV5su  
public class TestMethod { V_Ow
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=/xTUI4  
public TestMethod() C1 qyjlR  
{ ///xx/weblogic60b2_win.exe a&yIH;-  
try{ lLD-QO}
/  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); B{IYVviiP  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5);
7gIK+1
`  
SiteFileFetch fileFetch = new SiteFileFetch(bean); C~\/FrO?  
fileFetch.start(); @R+bR<}]  
} \Kh@P*7  
catch(Exception e){e.printStackTrace ();} E]x)Qr2Ju  
hVQ TW[  
c-S_{~~  
} joaf0  
nv WTx4oy  
yP:/F|E$  
public static void main(String[] args) 7/*a
 
{ n7UZ&ab  
new TestMethod(); 2I!STP{!l  
} nsChNwPX  
} W)rE_tw,|  
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