http断点续传简单实现（java)

/* kD*r@s]=  
**SiteFileFetch.java XiW~? *Z  
*/ #EG$HX]  
package NetFox; <Dk6o`7^N  
import java.io.*; ks19e>'5Q  
import java.net.*; dQljG.PiK  
i U"2uLgb  
;X;q8J^_K_  
public class SiteFileFetch extends Thread { 0&Z+P?Wb4  
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!FA[ ]d4  
SiteInfoBean siteInfoBean = null; //文件信息Bean BG/Q7s-?K  
long[] nStartPos; //开始位置 .(g"(fgF  
long[] nEndPos; //结束位置 >S}^0vNZX  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 (/$a*$  
long nFileLength; //文件长度 Q'~3Ik  
boolean bFirst = true; //是否第一次取文件 ]iezwz`'  
boolean bStop = false; //停止标志 F<0GX!p4u  
File tmpFile; //文件下载的临时信息 }Gf9.ACQ  
DataOutputStream output; //输出到文件的输出流 D;! aix3  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） CbW>yr  
public SiteFileFetch(SiteInfoBean bean) throws IOException L)"E_  
{ ]5a,%*f+  
siteInfoBean = bean; AGGNJ4m  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); RLNto5?  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); n?mV(?N  
if(tmpFile.exists ()) +/U6p!  
{ M$Or|HT
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bFirst = false; ~5:-;ZbZ  
read_nPos(); hqc)Ydg_%  
} b wqd`C  
else ]k)h<)nY  
{ A}W}H;8x  
nStartPos = new long[bean.getNSplitter()]; 2fFGS.l  
nEndPos = new long[bean.getNSplitter()];  ovsI2  
} Y]neTX [ef  
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$:IEpV{  
!n3J6%b9y/  
} 1X-fiQJe  
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public void run()  %Z-B{I(  
{ 5pz(6gA  
//获得文件长度 3?r?)$Jk  
//分割文件 DAVgP7h'  
//实例FileSplitterFetch el3lR((H  
//启动FileSplitterFetch线程 t|]2\6acuc  
//等待子线程返回 D:#e;K  
try{ VRA0p[  
if(bFirst) `VXC*A
  
{ a&C}'e"  
nFileLength = getFileSize(); X;Q
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if(nFileLength == -1) #xNXCBl]O  
{ NsF8`rg  
System.err.println("File Length is not known!"); $E6bu4I  
} VWT\wAL  
else if(nFileLength == -2) Z"5ew
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{ E-i<^&E  
System.err.println("File is not access!"); !cA4erBP  
} kpx2e2C|  
else 4n}^1eQ9  
{ M?.[Rr-uw  
for(int i=0;i<nStartPos.length;i++) ^nN@@\-5  
{ Zd<8c^@  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); !~QmY,R  
} ]:n! \G  
for(int i=0;i<nEndPos.length-1;i++) !A=>B=.|D  
{ o06vC  
nEndPos = nStartPos[i+1]; %dDwus  
} M2rgB%W)m  
nEndPos[nEndPos.length-1] = nFileLength; *,#T&M7D  
} R6E.C!EI  
} :M9 E  
 o
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-Ou@T#h"  
//启动子线程 a9niXy}a(  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; F8OE  
for(int i=0;i<nStartPos.length;i++) gQlL0jAV  
{ .!yw@kg  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 0})mCVBY  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), #9u2LK  
nStartPos,nEndPos,i); 3}V-'!  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); lAAs/  
fileSplitterFetch.start(); ~spfQV~  
} #7"*Pxb#A  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), HN~  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); (@ixV$Y  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", G;yh$n<"  
nEndPos = " + nFileLength); Ika(ip#]=  
// fileSplitterFetch[nPos.length-1].start(); 5~E'21hJ  
M
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d'*:2;)g^  
//等待子线程结束 Gb_y"rx?0  
//int count = 0; g4NbzU[I  
//是否结束while循环 h?+bW'm  
boolean breakWhile = false; k/mO(i%qi  
} 0x'm  
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while(!bStop) =.yKl*WV{  
{  "?(N  
write_nPos(); MrFi0G7u  
Utility.sleep(500); =x^b  
breakWhile = true; 4.qW ~W{  
5,u'p8}.  
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for(int i=0;i<nStartPos.length;i++) mQqv{1  
{ $G.ws  
if(!fileSplitterFetch.bDownOver) eZk4$y  
{ GEQ3r'B|  
breakWhile = false; L0dj 76'M  
break; CH4 ~9mmE  
} t182&gpd`  
} #0gwN2Nv"L  
if(breakWhile) lCC(N?%Q  
break; 8oVQ:' 6  
/4lm=ZE/  
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//count++; 8e*1L:oB!  
//if(count>4) +c-?1j  
// siteStop(); "*N=aHsj  
} 3 F ke#t  
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/`vn/X^?^  
System.err.println("文件下载结束！"); _pe_w{V-b6  
} xIb^x=|h  
catch(Exception e){e.printStackTrace ();} f_qW+fN::s  
} rXG?'jN  
C)8>_PY[M  
$2lPUQZ<5  
//获得文件长度 41Htsj  
public long getFileSize() v cZg3:j  
{ QfHO3Y6h[  
int nFileLength = -1; qmWn$,ax  
try{ ubZcpqm?Q  
URL url = new URL(siteInfoBean.getSSiteURL()); w]
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ^;=L|{Xl  
httpConnection.setRequestProperty("User-Agent","NetFox"); /swNhDQ"o  
]F81N(@:F  
8,m3]Lg  
int responseCode=httpConnection.getResponseCode(); `R+I(Cb  
if(responseCode>=400) (@"5:M  
{ =%+O.  
processErrorCode(responseCode); @Wb_Sz4`  
return -2; //-2 represent access is error i6y$P6s  
} @x@*=  
^qP}/H[QT  
{'
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String sHeader; /;rPzP4K6  
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for(int i=1;;i++) vl
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{ t/`~(0F  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); #y:,owo3I  
//Utility.log(in.readLine()); @fz!]/  
sHeader=httpConnection.getHeaderFieldKey(i); EBl?oN7E  
if(sHeader!=null) %zCV>D  
{ +dgHl_,i  
if(sHeader.equals("Content-Length")) ZgD%*bH*B  
{ .\6q\7Ej  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); |*5803h  
break; d$}z,~sN  
} ^+'[:rE  
} ~Y.I;EPKt  
else yy*8Aw}  
break; 9z0G0QW[  
} *fj5$T-Z  
}  <RaM@E  
catch(IOException e){e.printStackTrace ();} UG5AFZ\  
catch(Exception e){e.printStackTrace ();} {#o0vWS>  
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Utility.log(nFileLength); <QcQ.b  
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return nFileLength; tzn+ M0'  
} [)wLj
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CNkI9>L=W`  
//保存下载信息（文件指针位置） Vhi4_~W3j]  
private void write_nPos() )A1u uW (  
{ Am @o}EC  
try{ XGCjB{IV  
output = new DataOutputStream(new FileOutputStream(tmpFile)); tP0\;W  
output.writeInt(nStartPos.length); n
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for(int i=0;i<nStartPos.length;i++) K275{ydN  
{ nd4Z5=X  
// output.writeLong(nPos); jo}yeGbU  
output.writeLong(fileSplitterFetch.nStartPos); A6Vb'Gq
v{  
output.writeLong(fileSplitterFetch.nEndPos); FBP'AL|  
} km,I75o.  
output.close();  gmW-#.  
} V=cJdF  
catch(IOException e){e.printStackTrace ();} $c0<I59&|  
catch(Exception e){e.printStackTrace ();} uG){0%nX  
} ~cL)0/j}  
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//读取保存的下载信息（文件指针位置） =v:}{~M^$  
private void read_nPos() %5yP^BL0  
{ uy'qIq  
try{ gCL?{oVU  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); a9N$I@bi]  
int nCount = input.readInt(); ~LF1$Cai  
nStartPos = new long[nCount]; qvC2BQ  
nEndPos = new long[nCount]; bHK[Z5  
for(int i=0;i<nStartPos.length;i++) ;BmPP
,  
{ UY}EW`$#m  
nStartPos = input.readLong(); dIq*"Ry+~  
nEndPos = input.readLong(); Memb`3  
} HrS-o=  
input.close(); `P/87=h  
} w/,A@fLL  
catch(IOException e){e.printStackTrace ();} 
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catch(Exception e){e.printStackTrace ();} [U@;EeS  
} E@J}(76VS  
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private void processErrorCode(int nErrorCode) JE_GWgwdv  
{ m}32ovpw  
System.err.println("Error Code : " + nErrorCode); #B6$r/%  
} a^eR~efdu@  
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//停止文件下载 SNrX(V::z  
public void siteStop() 2= )V"lR\  
{ qS/ 'Kyp_  
bStop = true; pebNE3`#  
for(int i=0;i<nStartPos.length;i++) Im"8+756  
fileSplitterFetch.splitterStop(); X- P%^mK  
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} (YY!e2  
}  ,8)aK
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//负责部分文件的抓取 S76xEL  
**FileSplitterFetch.java d;g]Oe
F  
*/ TeHxqWx  
package NetFox; nkkUby9  
nn8uFISb  
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import java.io.*; M!Ywjvw*)3  
import java.net.*; }_fVv{D   
FPkig`(3  
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public class FileSplitterFetch extends Thread { V>"NVRY  
e/Y&d9` I  
!|-:"hE1h  
String sURL; //File URL yHs'E4V`$  
long nStartPos; //File Snippet Start Position SD.c9  
long nEndPos; //File Snippet End Position ~EO=;a_  
int nThreadID; //Thread's ID 2>vn'sXdj  
boolean bDownOver = false; //Downing is over (Eo#oX  
boolean bStop = false; //Stop identical ZW ZKyJQ  
FileAccessI fileAccessI = null; //File Access interface -c p)aH)  
"9OOyeKu%  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException oRHWb_$"  
{ t]6 4=  
this.sURL = sURL; kj@m5`G  
this.nStartPos = nStart; +K61-Div  
this.nEndPos = nEnd; %iD'2e:  
nThreadID = id; x?2y^3<5  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 vqRW^>~-B  
} H1e^/JD)  
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18JAca8Zs  
public void run() Jm3iYR+,  
{ ca"20NQ)  
while(nStartPos < nEndPos && !bStop) ktiC*|fd  
{ 9m}c2:p  
p 4Y2AQ9  
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try{ G;;iGN  
URL url = new URL(sURL); F17nWvF  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); J-Wphc!m  
httpConnection.setRequestProperty("User-Agent","NetFox"); UP@-@syGw  
String sProperty = "bytes="+nStartPos+"-"; W_ubgCB  
httpConnection.setRequestProperty("RANGE",sProperty); $qk(yzY  
Utility.log(sProperty); 8p.O rdp  
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InputStream input = httpConnection.getInputStream(); uDG#L6  
//logResponseHead(httpConnection); u|8yV.=R  
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byte[] b = new byte[1024]; 'fIirGOl  
int nRead; ?iaD;:'qE  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) j~`rc2n%  
{ q/^&si  
nStartPos += fileAccessI.write(b,0,nRead); <rFKJ^B  
//if(nThreadID == 1) 3&7$N#v  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ,XmyC7y<  
} "~aCW~  
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c!=^C/5Ee  
Utility.log("Thread " + nThreadID + " is over!"); IQQWp@w#8  
bDownOver = true; Zn"1qLPF  
//nPos = fileAccessI.write (b,0,nRead); /]"2;e-s+  
} Wo~#R   
catch(Exception e){e.printStackTrace ();} L\y>WR%s  
} %SD=3UK6  
} Pdw[#X<[`  
.+Fh,bNYK  
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//打印回应的头信息 e$y VV#  
public void logResponseHead(HttpURLConnection con) H| 1O>p&  
{ )gP0+W!u  
for(int i=1;;i++) Jp]eFaqp  
{ i-_ * 5%A  
String header=con.getHeaderFieldKey(i); x1{gw 5:  
if(header!=null) xk$U+8K  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); J\x.:=V  
Utility.log(header+" : "+con.getHeaderField(header)); (lR9x6yf  
else "1Oe bo2  
break; '{xPdN  
} nnPY8pdjSD  
} %#,EqN  
W
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public void splitterStop() 6!^&]4  
{ uRfFPOYH  
bStop = true; G@Y!*ZH*f  
} /htM/pR  
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j  
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} 8RJ^e[?o(  
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26Jb{o9Z<  
/* y}t1r |p  
**FileAccess.java 3/q)%Z^=  
*//文件访问(定位，写) 5x:dhkW  
package NetFox; rW(<[2vg  
import java.io.*;  N\9Wxz$  
nVt,= ?_ U  
O^,%V{]6\  
public class FileAccessI implements Serializable{ 08TeGUjJ  
 F6\Hqv  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 s35`{PR  
RandomAccessFile oSavedFile; x<es1A'u6  
long nPos; 8A ;)5!  
p\ }Ep  
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public FileAccessI() throws IOException *P.Dbb8vn  
{ R#x~f  
this("",0); 9Oe~e
 
} s}3`%?,6y  
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}[>X}"_e  
public FileAccessI(String sName,long nPos) throws IOException BrO" _  
{ 6*\WH%  
oSavedFile = new RandomAccessFile(sName,"rw"); p2/Pj)2  
this.nPos = nPos; KtO|14R:  
oSavedFile.seek(nPos); b&j}f  
} NB|yLkoDyI  
W1T% Q88  
[,)G\  
public synchronized int write(byte[] b,int nStart,int nLen)
<X b B;  
{ k:qS'  
int n = -1;
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try{ /Qnq,`z  
oSavedFile.write(b,nStart,nLen); !RD<"  
n = nLen; 4,]z  
} &xYO6_.  
catch(IOException e) +338z<'Z!  
{ x[_SNX"  
e.printStackTrace (); Lq6R_udp  
} ~]_U!r[FA  
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return n; p-Jp/*R5  
} NrK.DY4  
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} o<8('j   
.;$Ub[
  
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/* :yi?<  
**SiteInfoBean.java G=ly .  
*/ a7@':Rb n  
package NetFox; Oe~x,=X)  
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public class SiteInfoBean { 6Lb(oY}\3  

y9)w(y!  
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private String sSiteURL; //Site's URL }nUq=@ej  
private String sFilePath; //Saved File's Path U5RLM_a@M  
private String sFileName; //Saved File's Name 8=  kwc  
private int nSplitter; //Count of Splited Downloading File ki6Lt  
90[6PSXk  
I?&/J4o:  
public SiteInfoBean() q)j_QbW)  
{//nSplitter的缺省值为5 2Wn*J[5  
//default value of nSplitter is 5 T@%\?=P  
this("","","",5); 9,wD  
} ~jR4%VF  
[o"<DP6w  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) akA7))Q  
{ 2z9s$tp  
sSiteURL= sURL; [eO^C  
sFilePath = sPath; DYDeb i6  
sFileName = sName; )! eJW(  
this.nSplitter = nSpiltter; y '[VZ$^i  
S54q?sb_  
QdrZi.qKH  
} 2{Y~jYt{h  
awv$ }EFo  
w7@TM%nS  
public String getSSiteURL() Yu$QL@  
{ ZuFcJ?8i  
return sSiteURL; uCr :+"C  
} %E\zR/  
.He}f,!f<  
'eo/"~/*w  
public void setSSiteURL(String value) \$4 [qG=  
{ mCyn:+  
sSiteURL = value; IIG9&F$G  
} F[v:&fle  
PU,%Y_xR  
ysj5/wtO0  
public String getSFilePath() !-t,r%CG  
{ *4ido?  
return sFilePath; WcGg  
} dEZUK vo  
3K=%I+G(4  
]rG/?1'^i  
public void setSFilePath(String value) bksv2@ar  
{ yeI>b 1>Q  
sFilePath = value; .ht-*  
} lSg[
7lt  
I>GBnx L  
iF9d?9TWl  
public String getSFileName() YF)]B|I  
{ :h(`eC  
return sFileName; p$t
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} 57~y
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Mj{w/'  
public void setSFileName(String value) W=#AfPi$&  
{ GsmXcBzDw2  
sFileName = value; egvb#:zW?  
} :KgH
7s}  
$AT@r"  
~nTj't2R  
public int getNSplitter() b[GhI+_  
{ pCDN9*0/  
return nSplitter; ,3!$mQL=  
} -72EXO=|  
XC5/$3'M&  
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public void setNSplitter(int nCount) *f3StX  
{ \ )=WA!  
nSplitter = nCount; cT(6>@9@  
} jQ,Vs=*H  
} fd4C8>*7G  
M+0PEf.  
=gs-#\%  
/* +U1 Ir5Lx  
**Utility.java =#/Kg_RKL  
*/ {nbT$3=Zt  
package NetFox; &iInru3  
#R{>@]x`  
[lg!*  
public class Utility { ni&|;"Nt-  
0|RofL&o  
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public Utility() 00.x*v  
{ Jup)A`64  
:{#O  
QXZyiJX}  
} UWF \Vx*)b  
:oXSh;\  
//线程睡眠 t|$jgM  
public static void sleep(int nSecond) +?Ii=*7n  
{ QJ3#~GYNr  
try{ 7IkPi?&{  
Thread.sleep(nSecond); E?G'F3i  
} %W"u4 NT7  
catch(Exception e) ~x
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{ bAPMD  
e.printStackTrace (); V6X )L>!xx  
} ~<?Zj  
} %+H_V1F  
A<ds+0  
//日志 g#=<;X2  
public static void log(String sMsg) mUa#sTm  
{ 9F>`M  
System.err.println(sMsg); T@tsM|pI  
} Zp>v  
9h amxi  
 yf
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public static void log(int sMsg) "esuLQC  
{ >jX"  
System.err.println(sMsg);  px<psR5  
} ryVYY>*(K  
} d ItfR'$  
$<v4c5r]O  
Hw o _;fV  
/* az F!V  
**TestMethod.java 5c` ;~  
*/ Jh3  
package NetFox; F:!6B bC  
Nv
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9j:]<?D,A  
public class TestMethod { 8>9Mh!t}(I  
gx.\H3y  
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public TestMethod() ?4bYb]8Z  
{ ///xx/weblogic60b2_win.exe ~.:{ Ik]  
try{ _y~6b{T  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); /_0B5,6R  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); -qc'J<*^4  
SiteFileFetch fileFetch = new SiteFileFetch(bean); &DWSf`:Hx  
fileFetch.start(); o8R_Ojh  
} J"C9z{[Z&  
catch(Exception e){e.printStackTrace ();} -D~K9u]U_  
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ZaYiby@Ci  
} 8"j$=T6;W  
4Y8=  
,{PN6B  
public static void main(String[] args) |M;Nq@bRv  
{ "z{/*uM2<  
new TestMethod(); EHwb?{  
} J@2jx4   
} 93]63NY  
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