http断点续传简单实现（java)

/* z+(V2?xcvt  
**SiteFileFetch.java o!-kwtw`l  
*/ bs9X4n5  
package NetFox; +9!=pRq  
import java.io.*; 'NYW`,  
import java.net.*; U1^3 &N8  
6I!B>V#U+  
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public class SiteFileFetch extends Thread { R Q2DTQ-$  
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SiteInfoBean siteInfoBean = null; //文件信息Bean eN{ewn#0.  
long[] nStartPos; //开始位置 lzDA0MPI:  
long[] nEndPos; //结束位置 wXKg^%t\  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 DP5}q"l  
long nFileLength; //文件长度 x=%wPVJ  
boolean bFirst = true; //是否第一次取文件 dn}'B%  
boolean bStop = false; //停止标志
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File tmpFile; //文件下载的临时信息 xh`4s  
DataOutputStream output; //输出到文件的输出流 o@4
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） i_<GSUTTr/  
public SiteFileFetch(SiteInfoBean bean) throws IOException '74*-yd  
{ * ,#SwZ  
siteInfoBean = bean; !l5&>1?  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); m:x<maP#E  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 'M!*Ge  
if(tmpFile.exists ()) 3EO:Uk5<  
{ 'S#D+oF(1~  
bFirst = false; s9F{UN3  
read_nPos(); 9L7jYy=A#  
} l:- <CbG  
else ~;/}D0k$x  
{ ^={s(B2  
nStartPos = new long[bean.getNSplitter()];  Xn=  
nEndPos = new long[bean.getNSplitter()]; f{+n$Cos  
} ~U$ioQy<  
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} +Jw+rjnP  
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public void run() 2C[xrZa^  
{ o_R_  
//获得文件长度 ffI z>Of:  
//分割文件 n}L Jt  
//实例FileSplitterFetch kxWcWl8  
//启动FileSplitterFetch线程 i)=dp!Bx^  
//等待子线程返回 *c>B,  
try{ zr@HYl  
if(bFirst) N.F
//n  
{ B x-"<^<  
nFileLength = getFileSize(); F~;UD<<"H  
if(nFileLength == -1) ":W$$w<  
{ x.kIzI5  
System.err.println("File Length is not known!"); PQvpJFpb~h  
} SbK6o:[  
else if(nFileLength == -2) =QS%D*.|D  
{ ocPM zq-  
System.err.println("File is not access!"); \#7@"~<  
} J-
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else eJ+@<+vr;x  
{ QA=mD^A  
for(int i=0;i<nStartPos.length;i++) GD@|XwK){  
{ RGe2N|  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ,%d?gi"&  
} R4g;-Ci->  
for(int i=0;i<nEndPos.length-1;i++) d:3OC&  
{ t .-%@,s  
nEndPos = nStartPos[i+1]; R q9(<'F  
} =g{Hs1W  
nEndPos[nEndPos.length-1] = nFileLength; y134m  
} yt[*4gF4  
} Xv2Q8-}w  
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//启动子线程 0x,NMS  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; pKkBAr,  
for(int i=0;i<nStartPos.length;i++) `EWQ>m+  
{ BFvRU5&Sz  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Pq3m(+gf  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ZVni'ym  
nStartPos,nEndPos,i); p5`={'>-  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); AQjf\i  
fileSplitterFetch.start(); wu~?P`  
} S1U>Q~ZPA  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), $SfYO!n7Q  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); /pQUu(~h_  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Ft<B[bQ  
nEndPos = " + nFileLength); ycj\5+g  
// fileSplitterFetch[nPos.length-1].start(); Rj!9pwvT  
+j(7.6ia  
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//等待子线程结束 r^T+I3  
//int count = 0; CfEACH4_  
//是否结束while循环 '7JM/AcC#K  
boolean breakWhile = false; -)9aY.  
0mR^%+~  
cP^c}e*;NS  
while(!bStop) N7UGgn=  
{ QC<O=<$Q[  
write_nPos(); CXh>'K  
Utility.sleep(500); w`
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breakWhile = true; o:PdPuZVR  
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for(int i=0;i<nStartPos.length;i++) 2Dw}o;1'  
{ X}ft7;Jpy  
if(!fileSplitterFetch.bDownOver) (w1$m8`=  
{ s(pNg?R  
breakWhile = false; d8J(~$tXQN  
break; n+D93d9LP  
} [!Zyp`:  
} !`0 El',gY  
if(breakWhile) 9w.ZXd  
break; Q?V'3ZZF!  
tqXCj}mR  
>~*}9y0$  
//count++; v~:'t\n  
//if(count>4) j2s{rQQ  
// siteStop(); eOZ"kw"uHu  
} _j2q  
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,m[#<}xXA  
System.err.println("文件下载结束！"); j7yUya&
 
}  Y3g<%6  
catch(Exception e){e.printStackTrace ();} TEQs9-Uy  
} 'Esz#@R  
q$kx/6=k  
F4$9r^21r  
//获得文件长度 85vyt/.,k  
public long getFileSize() {sF;R.P&r  
{ ODKHI\U  
int nFileLength = -1; l,ic-Y1  
try{ @umn#*  
URL url = new URL(siteInfoBean.getSSiteURL()); 4P?R "Lk  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); YQ`88z  
httpConnection.setRequestProperty("User-Agent","NetFox"); r<!/!}fE,  
zxC~a97`  
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int responseCode=httpConnection.getResponseCode(); OZ4%6/  
if(responseCode>=400) `>u^Pm  
{ oT i$@q  
processErrorCode(responseCode); FJ2~SKWT  
return -2; //-2 represent access is error z=C<@ki`  
} %mRnJgV5k  
Y
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Ww =ksggpB  
String sHeader; ZY*_x)h+#7  
(97&mhs3  
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for(int i=1;;i++) ^K0oJg.E  
{ OjsMT]  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); y*T@_on5  
//Utility.log(in.readLine()); 8qwPk4  
sHeader=httpConnection.getHeaderFieldKey(i); nZ4@g@e2
 
if(sHeader!=null) O'S9y  
{ LF ;gdF%@  
if(sHeader.equals("Content-Length")) Nt~G {m  
{ >6:UWvV1  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); H=6-@+ !o  
break; jH[{V[<#X  
} VEx )  
} m%U$37A1  
else y4,t=Gq7^  
break; =U}!+ 8f  
} ;!B>b)%  
} 2#@-t{\3-p  
catch(IOException e){e.printStackTrace ();} 3j\Py'};  
catch(Exception e){e.printStackTrace ();} !RwMUnp  
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Utility.log(nFileLength); $d Nmq  
}b+$S'`Bv  
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return nFileLength; :.crES7<[X  
} P.3kcZ   
|`O210B@  
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//保存下载信息（文件指针位置） 6 -IThC  
private void write_nPos() H={5>;8G  
{ 0}-
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try{ RY
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output = new DataOutputStream(new FileOutputStream(tmpFile)); qU^`fIa  
output.writeInt(nStartPos.length); ' pfkbmJ  
for(int i=0;i<nStartPos.length;i++) },,K6*P  
{ @Uqcym.  
// output.writeLong(nPos); 7W=s.Gy7G\  
output.writeLong(fileSplitterFetch.nStartPos); ?tkd5kE  
output.writeLong(fileSplitterFetch.nEndPos); t8uaNvUM}e  
} vs{xr*Ft  
output.close(); F@1Eg
  
} ?:Rw[T@ l  
catch(IOException e){e.printStackTrace ();} M-A{{q   
catch(Exception e){e.printStackTrace ();} QURpg/<U  
} 9j<7KSj  
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//读取保存的下载信息（文件指针位置） QxiAC>%K  
private void read_nPos() t]+h.  
{ \N.Bx
  
try{ 'h>CgR^NM1  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 41c4Xj?'  
int nCount = input.readInt(); cD9.L  
nStartPos = new long[nCount]; qjH/E6GGg  
nEndPos = new long[nCount]; HJ!P]X_J1  
for(int i=0;i<nStartPos.length;i++) WnQ+  
{ ?-=<7 ~$  
nStartPos = input.readLong(); %)=c#H1  
nEndPos = input.readLong(); >
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} V-lp';bD  
input.close(); Mc6v  
} h! wd/jR  
catch(IOException e){e.printStackTrace ();} WB\chb%ej#  
catch(Exception e){e.printStackTrace ();} ^"+Vx9H"{  
} /e7BW0$1  
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 \1?:  
private void processErrorCode(int nErrorCode) ?{r-z3@ N  
{ 5$c*r$t_RK  
System.err.println("Error Code : " + nErrorCode); ]f*.C9Y  
} 3
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//停止文件下载 nw=:+?  
public void siteStop() ZX0!BS  
{ du&9mOrr  
bStop = true; 6,(S}x YDZ  
for(int i=0;i<nStartPos.length;i++) R!2E`^{Wl  
fileSplitterFetch.splitterStop(); vpoJ{TPO  
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} dyt.(2  
} )pw53,7>aN  
//负责部分文件的抓取 uwu`ms7z 2  
**FileSplitterFetch.java `}#n
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*/ }h=3[pe
}  
package NetFox; `FAZAC\  
y>& s;  
]Mj N)%hT  
import java.io.*; URMxCL^"  
import java.net.*; >uJU25)|  
eMUsw5=  
RIq\IQ_|  
public class FileSplitterFetch extends Thread { g4GU
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N.-*ig.YR7  
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String sURL; //File URL [~k!wipK  
long nStartPos; //File Snippet Start Position -!X\xA/KN  
long nEndPos; //File Snippet End Position Ee'wsL  
int nThreadID; //Thread's ID iM"L%6*I^  
boolean bDownOver = false; //Downing is over W=2#Q2)  
boolean bStop = false; //Stop identical <4%PT2R  
FileAccessI fileAccessI = null; //File Access interface goc"+K  
NQ,2pM<*-  
9C|-|mo  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException nOK1Wc%/'  
{ ^o Q^/v~  
this.sURL = sURL; RT"JAJTi/  
this.nStartPos = nStart; '|nA
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this.nEndPos = nEnd; Cd7l+~*Y  
nThreadID = id; 1_z~<d @?;  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 aV G4Df  
} Y{2L[5_1  
% r0AhWv  
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public void run() ?]0bR]}y  
{ }c'T]h\S  
while(nStartPos < nEndPos && !bStop)
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{ 8:jakOeT  
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try{ z`Xc] cPi  
URL url = new URL(sURL); _OJ19Ry  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 0-8'.C1v  
httpConnection.setRequestProperty("User-Agent","NetFox"); xcQ:&q  
String sProperty = "bytes="+nStartPos+"-"; n(jrK9]  
httpConnection.setRequestProperty("RANGE",sProperty); s^GE>rf  
Utility.log(sProperty); Pi=B\=gs  
ykNPKzW:  
@vvGhJ1m`  
InputStream input = httpConnection.getInputStream(); 89J7hnJC  
//logResponseHead(httpConnection);  o*xft6U  
-\M;bQV[C  
idNg&'   
byte[] b = new byte[1024]; Fy^MI*}BZ  
int nRead; YBQ{/"v%|
 
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ?$%2\"wX~7  
{ ~s>Ud<l%r  
nStartPos += fileAccessI.write(b,0,nRead); _+. )8   
//if(nThreadID == 1) AmBLZ<f;  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); "K#zY~>L  
} =
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-qJO6OM  
Utility.log("Thread " + nThreadID + " is over!"); Il$Jj-)  
bDownOver = true; 8Oo16LPD  
//nPos = fileAccessI.write (b,0,nRead); `D0Hu!;
 
} *w6(nG'M{  
catch(Exception e){e.printStackTrace ();} _[S<Cb*1  
} AI2@VvB  
} Kl w9  
-PskUl'  
Cm#[$T@C  
//打印回应的头信息 rIJd(=  
public void logResponseHead(HttpURLConnection con) }N W0
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{ LRv[,]b  
for(int i=1;;i++) "ac$S9@~  
{ @fI2ZWN|  
String header=con.getHeaderFieldKey(i); QP!0I01  
if(header!=null) E,7b=t  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); cGS7s 8U  
Utility.log(header+" : "+con.getHeaderField(header)); "i;"  
else a fUOIM  
break; U )J/so)  
} ^-26K|{3  
} /U@Y2$TOF  
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public void splitterStop() I=K|1  
{ 6|]e}I@<2  
bStop = true; WXCZ }l  
} | gP%8nh'C  
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} YF<U'EVU-  
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br4 %(w(d  
/* |]j2T8_=  
**FileAccess.java $;B0x  
*//文件访问(定位，写) E>k!d'+tb  
package NetFox; *[b2
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import java.io.*; .@3bz  
obSLy Ed  
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public class FileAccessI implements Serializable{ YH'j"|{  
o
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 #iP5@:!Wm~  
RandomAccessFile oSavedFile; KU (g Zy  
long nPos; 5DnX8t+d  
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public FileAccessI() throws IOException YQ7tZl;:t  
{ Hjc *WTu  
this("",0); -*~~00w  
} GbJVw\5Z*  
"UTAh6[3oD  
*/A ~lR|  
public FileAccessI(String sName,long nPos) throws IOException ZoroK.N4A%  
{ ,nz3S5~  
oSavedFile = new RandomAccessFile(sName,"rw"); MUvgmJsN  
this.nPos = nPos; 7r wNjY#  
oSavedFile.seek(nPos); R6-Z]Hu  
} {V5eHn9/Q'  
Q(h/C!rKe  
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public synchronized int write(byte[] b,int nStart,int nLen) p+; La  
{ >PONu]^  
int n = -1; |oV_7%mlu  
try{ y rmi:=N(  
oSavedFile.write(b,nStart,nLen); 29r(Y  
n = nLen; b]Z>P{ j  
} (v1~p3H  
catch(IOException e) l[M?"<Ot;  
{ DI7g-h8`  
e.printStackTrace (); (K3eb  
} ?$Ii_.  
%M u$0~ct"  
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return n; @"'$e_jj"  
} T9&bY>f?  
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} i'`[dwfS  
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jRNDi_u?Wb  
/* )jHH-=JM  
**SiteInfoBean.java eD?f|b
if  
*/ Ff{dOV.i  
package NetFox; _"G./X  
U['|t<^uf  
hLF;MH@  
public class SiteInfoBean { B):hm  
Ym$=^f]-  
y$U(oIU>  
private String sSiteURL; //Site's URL FgTWym_  
private String sFilePath; //Saved File's Path ]Ofs,U^  
private String sFileName; //Saved File's Name n5;>e&  
private int nSplitter; //Count of Splited Downloading File #D|n6[Y'.t  
E>Lgf&R#W  
mk]8}+^.  
public SiteInfoBean() BSHtoD@e7  
{//nSplitter的缺省值为5 D%!GY1wdn  
//default value of nSplitter is 5 !FHm.E_>  
this("","","",5); c!dc`R  
} 0*XCAnJ^_  
D2MWrX  

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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) jCp`woV  
{ ]8dzTEjk  
sSiteURL= sURL; W+u-M>Cj6  
sFilePath = sPath; Y[Eq;a132  
sFileName = sName; IHcR/\mz  
this.nSplitter = nSpiltter; Ucd~-D  
z`(">J  
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} oJe`]_XZ  
i:\|G^h  
aDZ]{;  
public String getSSiteURL() MeW?z|x`'  
{ 2i)vT)~  
return sSiteURL; h@%a+6b?  
} I@q(P>]X9  
LGT?/gup  
'ocPG.PaU  
public void setSSiteURL(String value) = ow=3Ku  
{ vXT>Dc2\!  
sSiteURL = value; Z,7VOf6g  
} 12HE=  
<P.'r,"[  
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public String getSFilePath() 'mO>hD`V  
{ =SVb k  
return sFilePath; Js/QL=,  
} tZan1C%p>  
<BjrW]pM  
][`%vj9r  
public void setSFilePath(String value) _kT{W]  
{ RJOW#e :  
sFilePath = value; 5[Uv%A?H#_  
} _
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x4-_K%  
1:22y:^j  
public String getSFileName() 52t6_!y+V  
{ cUC!'+L  
return sFileName; aM YtWj  
} /_</m?&.U&  
I'0{Q`}  
l;i/$Yu7  
public void setSFileName(String value) )W*A[c 2  
{ #Fz/}lO  
sFileName = value; M.\V/OX  
} 4/AE;yX  
I`;SA~5  
^MO})C  
public int getNSplitter() }56WAP}Z 4  
{ >)+N$EN  
return nSplitter; 58P[EMhL  
} il% u)NN  
|H.ARLS  
d r$E:kr  
public void setNSplitter(int nCount) o>\o=%D.a  
{ pD;fFLvN  
nSplitter = nCount; :f~qt%%/  
} pv]" 2'aQ  
} kxmc2RH>nB  
"/Pq/\,R|  
`#"xgOSP>  
/* v?0F  
**Utility.java ?z&5g-/b  
*/ Z):Nd9  
package NetFox; }CL7h;5N 3  
oS^KC}X  
|=AaGJx  
public class Utility { F}?4h Dt  
n j2=}6  
-ARks_\  
public Utility() i!)\m0Wm  
{ 0ZJj5<U  
($-m}UF\/  
2P^x'I  
} Raf(m,o(  
9e
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//线程睡眠 &%m%b5  
public static void sleep(int nSecond) quRTA"!E  
{ K/K|[=bl  
try{ @Gt.J*!s/  
Thread.sleep(nSecond); psUT2  
} ih-J{1  
catch(Exception e) jl5&T
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{ )Z)Gb~G  
e.printStackTrace (); LGK@taw^  
} _!,Ees=b  
} ^h^.;Iqr=  
"SRS{-p0  
//日志 aK/fZ$Qc  
public static void log(String sMsg)
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{ ]kd:p*U6P  
System.err.println(sMsg); N(V_P[]"*,  
} aa"3 Io  
A9;,y'm^8  
$O%"[w  
public static void log(int sMsg) sou~m,#  
{ Jj?HOtaM  
System.err.println(sMsg); O]'2<;  
} RL3*fRlb  
} %SuELm  
xpc{#/Nk  
iBI->xU[U  
/* Cz &3=),G  
**TestMethod.java :
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*/ -V-I&sO<  
package NetFox; zwz_K!229  
Ec@cW6g(%  
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public class TestMethod { qw1W}+~g  
#k?.dWZ!  
L9-Jwy2(>  
public TestMethod() p=odyf1hK  
{ ///xx/weblogic60b2_win.exe o(4gh1b%  
try{ /l_u $"  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); -K3d u&j  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); U.X`z3q
 
SiteFileFetch fileFetch = new SiteFileFetch(bean); u`D _  
fileFetch.start(); 4}s'xMT!  
} YxrMr9>l1  
catch(Exception e){e.printStackTrace ();} ` FOCX
;  
4XAs^>N+  
"blq)qo)  
} t<ZBp0  
==Xy'n9'  
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public static void main(String[] args) *ow`}Q  
{ bv VkN

 
new TestMethod(); b$yIM  
} -DK6(<:0  
} %P D}VF/Y  
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