http断点续传简单实现（java)

/* x<s|vgl|  
**SiteFileFetch.java SW#BZ
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*/ E+z18Lf?  
package NetFox; =53bLzr  
import java.io.*; )tD6=Iz^5  
import java.net.*; "XhOsMJ  
<5I1DF[  
jN6b*-2  
public class SiteFileFetch extends Thread { y AOg\+  
"5}%"-#  
+2Ql~w@$^l  
SiteInfoBean siteInfoBean = null; //文件信息Bean /W`$yM3  
long[] nStartPos; //开始位置 5%P[^}  
long[] nEndPos; //结束位置 ec?V[v  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 88g47>{X  
long nFileLength; //文件长度 }
/p/pVz  
boolean bFirst = true; //是否第一次取文件 +0"x|$f~  
boolean bStop = false; //停止标志 KmL$M  
File tmpFile; //文件下载的临时信息 thptm  
DataOutputStream output; //输出到文件的输出流 } L <,eV  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） Fu%X  
public SiteFileFetch(SiteInfoBean bean) throws IOException :+:6_x  
{ 5B{k\H;  
siteInfoBean = bean; +T2HE\  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Qci$YTwl>  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); jTfi@5aPY  
if(tmpFile.exists ()) g4wZvra6%)  
{ VgMP^&/gZ  
bFirst = false; m?;$;x~Dj  
read_nPos(); %2D17*eK  
} |l7%l&!  
else 4P%m>[  
{ 8*s7m   
nStartPos = new long[bean.getNSplitter()]; %iJ|H(P  
nEndPos = new long[bean.getNSplitter()]; Sl>>SP  
} _!!}'fMC  
M6Pw/S!  
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} !)c=1EX]"  
],[)uTZc  
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public void run() +j[`,5oS  
{ ErDL^M-`  
//获得文件长度 LeHiT>aX!  
//分割文件 Q0~j$Jc  
//实例FileSplitterFetch ^.vmF>$+I  
//启动FileSplitterFetch线程 (ua q<Cvg  
//等待子线程返回 rl?7W];  
try{ #*2Rp8n  
if(bFirst) ~;unpym'  
{ 62kb2C  
nFileLength = getFileSize(); w^{!U  
if(nFileLength == -1) =IHje;s  
{ CCqT tp  
System.err.println("File Length is not known!"); WeC(w+}p  
} /\J|Uj  
else if(nFileLength == -2) I60DUuF  
{ xmr|'}Pt[  
System.err.println("File is not access!"); p)3nyN=|_  
} :c7CiP  
else ?2ItB`<(  
{ ArzDI{1  
for(int i=0;i<nStartPos.length;i++) @B`Md3$7
 
{ QU/3X 1W  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); tg
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} eN/G i<  
for(int i=0;i<nEndPos.length-1;i++) OVR?*"N_  
{ mW4%2fD[  
nEndPos = nStartPos[i+1]; z(H?VfJo  
} q4ipumy*  
nEndPos[nEndPos.length-1] = nFileLength; l}}UFEA^  
} ;S JF%@x  
} vT7g<  
|nY~ZVTt/  
&U"X$aFc  
//启动子线程 hNbIpi=  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; >]&X ^V%Q#  
for(int i=0;i<nStartPos.length;i++) |^GyH$.  
{ ~R.dPUr  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), eko]H!Ov(  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), `#6x=24  
nStartPos,nEndPos,i); U<Jt50O  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Zw$ OKU  
fileSplitterFetch.start(); f=`33m5  
} SRL-Z&M  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), kus}WJ  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); `,Orf ZMb  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", _k2w(ew?  
nEndPos = " + nFileLength); >85zQ 1aL  
// fileSplitterFetch[nPos.length-1].start(); ?QpNjsF  
S~3\3qt$  
mqFq_UX/T  
//等待子线程结束 ;&f1vi4  
//int count = 0; 1R*=.i%W  
//是否结束while循环 6D/'`  
boolean breakWhile = false; o8z)nOTO;  
q`Q}yE>9  
)q3"t2-  
while(!bStop) $|a;~m>  
{ >I<PO.c!  
write_nPos(); G
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Utility.sleep(500); uZ(? >  
breakWhile = true; u~F~cDu  
w%xCTeK[  
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for(int i=0;i<nStartPos.length;i++) U7H9/<&o  
{ Qn=$8!Qqa  
if(!fileSplitterFetch.bDownOver) +K{LQsR]  
{ K)[8 H~Lm  
breakWhile = false; IR$(_9z  
break; NL!9U,h5|  
} NK/4OAt%  
} wss?|XCI  
if(breakWhile) K+),?Q ?.p  
break; lf$Ve  
;dQAV\  
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//count++; (-"`,8K 2}  
//if(count>4) YBjdp=als  
// siteStop(); tu}>:mk  
} KQmZ#W%2m  
N 8t=@~]  
_H\<[-l  
System.err.println("文件下载结束！"); ebM{OI  
} 3?E}t*/  
catch(Exception e){e.printStackTrace ();} dGkgaC+  
} JP'= UZ'  
D:E9!l'  
x-_vl 9P)  
//获得文件长度 Z[ZDQ o1  
public long getFileSize() |4C^$  
{ m,tXE%l  
int nFileLength = -1; +>YfRqz:KB  
try{ +jV_W
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URL url = new URL(siteInfoBean.getSSiteURL()); ;BBpN`T  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); g>0vm2|  
httpConnection.setRequestProperty("User-Agent","NetFox"); <qeCso  
2 ZG@!Y|  
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int responseCode=httpConnection.getResponseCode(); LP<<'(l`  
if(responseCode>=400) wahZK~,EaY  
{ ~F[L4y!sL  
processErrorCode(responseCode); Yc#IFmC}  
return -2; //-2 represent access is error DTY<0Q.  
} ]WL|~mG  
LWmB, Zf/  
wE Qi0!  
String sHeader; fx?$9(r,  
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6|=j+rScv  
for(int i=1;;i++) f/ahwz  
{ PT]GJ<K/  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ClQe4uo{  
//Utility.log(in.readLine()); <P4FzK  
sHeader=httpConnection.getHeaderFieldKey(i); OJ3UE(,I=  
if(sHeader!=null) @d&H]5  
{ o8S"&O ?  
if(sHeader.equals("Content-Length")) m 7LUrU  
{ 2wlKBSON  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); id,NONb\  
break; 3V;gW%
>  
} 8<dOMp;}r  
} 8r:M*25  
else r>|-2}{N/  
break; .i/m  
} ht6244:  
} A lwtmDa  
catch(IOException e){e.printStackTrace ();} -9+se  
catch(Exception e){e.printStackTrace ();} k`VM2+9h'^  
$c9k*3{<+A  
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Utility.log(nFileLength); A Y9 9!p  
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return nFileLength; 0(\+-<  
} ?IW_O~Js  
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//保存下载信息（文件指针位置） PHra+NY#A  
private void write_nPos() AEg(m<t  
{ ZFxLBb:  
try{ EX "|H.(  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ,YLF+^w-  
output.writeInt(nStartPos.length); !:0v{ZQ  
for(int i=0;i<nStartPos.length;i++) ^[q /Mw  
{ Xs$Ufi  
// output.writeLong(nPos); ^mPPyT,(  
output.writeLong(fileSplitterFetch.nStartPos); (03pJV&K  
output.writeLong(fileSplitterFetch.nEndPos); 8]"(!i_;)  
} ^&[+H8$  
output.close(); ")UwkF  
} #h'@5 l  
catch(IOException e){e.printStackTrace ();} :td ~g;w  
catch(Exception e){e.printStackTrace ();} ";NRzY  
} -$-8W  
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//读取保存的下载信息（文件指针位置） Xu}U{x>  
private void read_nPos() \caH pof  
{ FN87^.^2S  
try{ MDO$m g  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ^vni&sJ  
int nCount = input.readInt(); wEEn?  
nStartPos = new long[nCount]; 0^l%j8/  
nEndPos = new long[nCount]; L^0v\  
for(int i=0;i<nStartPos.length;i++) }iiHr|l3  
{ %s=Dj2+  
nStartPos = input.readLong(); #I0pYA2m  
nEndPos = input.readLong(); jAhP> t:  
} lK(Fg  
input.close(); e XV@.  
} 7+,vTsCd  
catch(IOException e){e.printStackTrace ();} -n))*.V  
catch(Exception e){e.printStackTrace ();} Z~u9VYi!  
} Gt-UJ-RR y  
vNDu9ovs-  
3Qn!y\#  
private void processErrorCode(int nErrorCode) M {a #  
{ Le#spvV3J|  
System.err.println("Error Code : " + nErrorCode); 1|| nR4yK  
} LR&_2e^[  
m5c&&v6%"b  
^twivNB  
//停止文件下载 u=NG6
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public void siteStop() -,#+`>w  
{ -4 Ux,9
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bStop = true; "Ij
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for(int i=0;i<nStartPos.length;i++) `=)2<Ca;~@  
fileSplitterFetch.splitterStop(); r@}bDkx  
9Sg<K)Mc  
>hsuAU.UOR  
} 3vic(^Qh  
} =JO^XwUOo  
//负责部分文件的抓取 :nJgwp()@  
**FileSplitterFetch.java X_TiqV  
*/ NC"yDWnO'  
package NetFox; i'HQQWd  
QWO]`q`|  
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import java.io.*; 1,t)3;o$  
import java.net.*; /bVZ::A&_  
YZwaD b
 
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public class FileSplitterFetch extends Thread { /@oLe[Mz$  
Ib`-pRU;  
#bnb': f  
String sURL; //File URL `wz[='yM  
long nStartPos; //File Snippet Start Position pmc=NTr&<  
long nEndPos; //File Snippet End Position 3=.Y,ENM;  
int nThreadID; //Thread's ID u?H 2%hD  
boolean bDownOver = false; //Downing is over 6ghx3_%w  
boolean bStop = false; //Stop identical D]03eu  
FileAccessI fileAccessI = null; //File Access interface 1=VJ&D;  
VD7i52xS  

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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 1%
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{ '+y_\  
this.sURL = sURL; 
#%,RJMv  
this.nStartPos = nStart; "M H6fF  
this.nEndPos = nEnd; msx-O=4g  
nThreadID = id; |zsbW9 W*m  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 7=}F{U  
} 2.I^Xf2  
[0;buVU.  
/R8p]  
public void run() yt0,^*t_  
{ S;\R!%t_  
while(nStartPos < nEndPos && !bStop) m@G i6  
{ <^R{U&Z@  
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try{ ^4Uw8-/9  
URL url = new URL(sURL); &l2TeC@;  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); .TB"eUy  
httpConnection.setRequestProperty("User-Agent","NetFox"); -apXI.  
String sProperty = "bytes="+nStartPos+"-"; tD=@SX'Y  
httpConnection.setRequestProperty("RANGE",sProperty); DocbxB={I  
Utility.log(sProperty); z%d#@w0X1  
`#s#it'y  
~W#sTrK

 
InputStream input = httpConnection.getInputStream(); Gwec
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//logResponseHead(httpConnection); :' #\  
ii|?;  

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byte[] b = new byte[1024]; m?CZQq,  
int nRead; sH#X0fG  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 2b@tj 5  
{ z}4L=KR\v  
nStartPos += fileAccessI.write(b,0,nRead); ,_v|#g@{  
//if(nThreadID == 1) n.6
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// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); iAn'aW\TF  
} D)b}f`  
s'HD{W
`  
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Utility.log("Thread " + nThreadID + " is over!"); a$11PBi[9  
bDownOver = true; _'0 @%P%
 
//nPos = fileAccessI.write (b,0,nRead); !kuX,*}q  
} A$/\1282  
catch(Exception e){e.printStackTrace ();} ,ZE?{G{tuj  
} "E*e2W  
} wD\ZOn_J  
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jQs>`P-CM  
//打印回应的头信息 O
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public void logResponseHead(HttpURLConnection con) @J'YV{]  
{ %at
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for(int i=1;;i++) _ Y2 U7W  
{ JgRYljQi2  
String header=con.getHeaderFieldKey(i); _c(4o:  
if(header!=null) T3%C%BcX  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); .10y0FL4  
Utility.log(header+" : "+con.getHeaderField(header)); |Bo .4lX  
else L,[;k  
break; T Eu'*>g  
} -~f511<  
} *Ust[u  
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public void splitterStop() _D7]-3uC!  
{ 6i@\5}m=  
bStop = true; <W)u{KS#TY  
} 9nSWE W  

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} ZAKeEm2A  
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/* .4y>QN#VL  
**FileAccess.java 7Cqcb>\X  
*//文件访问(定位，写) 0u B'g+MU`  
package NetFox; 6X2PYJJZ  
import java.io.*; uGU;Y'W)  
* *H&+T/B  
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public class FileAccessI implements Serializable{ \00DqL(Oj`  
Z"-L[2E/{!  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ~V=<3X  
RandomAccessFile oSavedFile; una%[jTc  
long nPos; nKr9#JebRC  
K4Dp:2/K%  
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public FileAccessI() throws IOException Q _iO(qu 6  
{ WG71k8af  
this("",0); \G@wp5  
} Q^Ql
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public FileAccessI(String sName,long nPos) throws IOException G_H?f\/  
{ Sw&!y$ed  
oSavedFile = new RandomAccessFile(sName,"rw"); 0JuD^  
this.nPos = nPos; TJ8E"t*)
 
oSavedFile.seek(nPos); +k<w!B*  
} x`RTp:#  
>O9o,o/6R  
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public synchronized int write(byte[] b,int nStart,int nLen) 6R;3%-D  
{ q"qo.TPh|$  
int n = -1; E\8  
try{ b,TiMf9},h  
oSavedFile.write(b,nStart,nLen); 1S
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n = nLen; #:x4DvDkR  
} 2aA`f7  
catch(IOException e) Uggw-sRU  
{ ~tFqb<n  
e.printStackTrace (); <|Yj%f  
} qZEoiNH(Tj  
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LK9g0_  
return n; $4FX(O0Q@  
} m(iR
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:K82sCy%5  
} ^i)hm  
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lS^(&<{  
/* =,!\~`^  
**SiteInfoBean.java "<+ih0Ma  
*/ T=a=B(  
package NetFox; d@0Kr5_  
b IW'c_ ,  
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public class SiteInfoBean { UM*jKi2]"  
<AlZ]
~Yct  
#3=P4FUz.  
private String sSiteURL; //Site's URL ?Ucu#UO
 
private String sFilePath; //Saved File's Path HBE.F&C88  
private String sFileName; //Saved File's Name 3ss6_xd+  
private int nSplitter; //Count of Splited Downloading File ^\:8w0Y^  
"&Dx=Yf  
Z BUArIC  
public SiteInfoBean() {yU+)t(.  
{//nSplitter的缺省值为5  >YtdA  
//default value of nSplitter is 5 $2DuB  
this("","","",5); dBV7Te4L  
} F(#rQ_z]  
ZPN roCK`  
,bE$| x'  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) y;?ie]3G  
{ JPM))4YDR  
sSiteURL= sURL; L(>=BK*  
sFilePath = sPath; +z9@:L  
sFileName = sName;
1=7jz]t  
this.nSplitter = nSpiltter; Hy"x  
j;_c+w!P  
Q zZ;Ob]'  
} Z4$cyL'
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[ =x s4=  
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public String getSSiteURL() I V%VU  
{ )Rat0$6  
return sSiteURL; 8n BL\{'B[  
} Ioy  
4Tc&IwR  
Zc |/{$>:W  
public void setSSiteURL(String value) Cd79 tu|  
{ -7uwOr  
sSiteURL = value; qjAWeS/  
} lDC$F N  
R`";Z$~{  
)Dp/('Z2  
public String getSFilePath() LLWB
  
{ AB Xl  
return sFilePath; _{vkX<s  
} `dMqe\o
%!  
F
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public void setSFilePath(String value) *{undZ?(>  
{ v1k)hFjPK  
sFilePath = value; 5m=I*.qE  
} MC((M,3L  
K'iIJA*Sn  
b?4/#&z]  
public String getSFileName() M}_i52  
{ jJ4qR:]  
return sFileName; 8By,#T".  
} 2-zT$`
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N!Qg;(  
public void setSFileName(String value) WD;Y~|  
{ z)XRx:YU;$  
sFileName = value; < _$%@4 L  
} bk<\ujH  
Sx:Ur>?hd5  
t#nn@Yf  
public int getNSplitter() LNl#h  
{ 3QSZ ZJ  
return nSplitter; xt'tL:d  
} .,~(%#Wl$  
RO0>I8c1c  
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public void setNSplitter(int nCount) S0g'r !;6  
{ @ DZD  
nSplitter = nCount; =z{JgD/  
} +5.t. d  
} ri C[lB  
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]Mj/&b>"e  
/* Sp}D;7  
**Utility.java biozZ  
*/ vQF vtwd  
package NetFox; GEjd7s]C  
VKm!Ri$  
`G1&Z]z  
public class Utility { !|2VWI}  
.t&R>9cZ^  
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public Utility() (3[z%@I  
{ 7@.cOB`y@3  
1[*UYcD  
*'"T$i
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} Nf3.\eR  
Bb&^{7  
//线程睡眠 #QvMVy  
public static void sleep(int nSecond) ,U*)2`[  
{ a</D_66  
try{ ?Y:x[pOe  
Thread.sleep(nSecond); ;)Kh;;e  
} vN4Qdpdb  
catch(Exception e) =5D nR  
{ PqNFyQkl  
e.printStackTrace (); <)g8yA
  
} E^_wI>  
} {Z;jhR,  
x#~ x;)  
//日志 Sz{O2lY  
public static void log(String sMsg) 41#w|L \  
{ %or,{mmiM:  
System.err.println(sMsg); ,1q_pep~?%  
} <";,GaZQ  
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public static void log(int sMsg) UV}73Sp  
{ S1n3(U:m  
System.err.println(sMsg); j4FeSGa  
} sDgXU@  
} K|C^l;M6  
>Sa*`q3J  
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/* rOW-0B+N  
**TestMethod.java |W$DVRA  
*/ . .QB~  
package NetFox;
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nqR?l4 DX  
L?_7bXoD
 
public class TestMethod { DPrBFmHF  
s57N) 0kP  
2c<&eX8"  
public TestMethod() $=sXAK9   
{ ///xx/weblogic60b2_win.exe z sQo$p  
try{ i$^)UZJ&0  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); [=uo1%  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); |5I'CNi\  
SiteFileFetch fileFetch = new SiteFileFetch(bean); xy+QbDT  
fileFetch.start(); W$dn_9W  
} v]2S`ffP  
catch(Exception e){e.printStackTrace ();} q,<[hBri-  
O#nR>1h  
_ 7oV<  
} k<w(i k1bi  
89{HJ9}  
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public static void main(String[] args) @vgG1w  
{ uBg 8h{>  
new TestMethod(); /)N@M  
} ^/wfXm  
} s)voII&  
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