http断点续传简单实现（java)

/* 5;FP.{+  
**SiteFileFetch.java TRgY:R_  
*/ iN<(O7B;  
package NetFox; +R "AA_A?  
import java.io.*; UsLh)#}h  
import java.net.*; |?x^8e<*  
tLS<0  
@A [)hk&(R  
public class SiteFileFetch extends Thread { _YH<YOrMh  
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<Gr9^C  
SiteInfoBean siteInfoBean = null; //文件信息Bean n 5~=qQK2  
long[] nStartPos; //开始位置 v]WH8GI  
long[] nEndPos; //结束位置 =cdh'"XN  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 @Pxw
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long nFileLength; //文件长度 ,^.S0;D,Z  
boolean bFirst = true; //是否第一次取文件 ra]!4Kd'  
boolean bStop = false; //停止标志 h`?y2?O  
File tmpFile; //文件下载的临时信息 A#Xj]^-*  
DataOutputStream output; //输出到文件的输出流 *-9#/Cp  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） PSW#^o  
public SiteFileFetch(SiteInfoBean bean) throws IOException [zY!'cz?  
{ >65 TkAp  
siteInfoBean = bean; i[^k.W3gf  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); rW:iBq  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 5{')GTdX>  
if(tmpFile.exists ()) xe(MHNrj  
{ w`M]0'zls  
bFirst = false; 'oC$6l'rQ  
read_nPos(); (JevHdI*V  
} ;xSRwSNDi(  
else 65lOX$*{-  
{ "YuZ fL`bb  
nStartPos = new long[bean.getNSplitter()]; &c20x+  
nEndPos = new long[bean.getNSplitter()]; PPN q:,  
} kfVZ=`p}  
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a ]>VZOet  
} /M 0 p_4  
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public void run() ,SAbC*nq  
{ =]T|h  
//获得文件长度 {n\6BT
s  
//分割文件 Q5g,7ac8L  
//实例FileSplitterFetch !@( M_Z'  
//启动FileSplitterFetch线程 %=BtOM_2  
//等待子线程返回 9 >%+bA(  
try{ 60'6/3  
if(bFirst) -=}b;Kf-  
{ >Z}@7$(7!~  
nFileLength = getFileSize(); mLJDxh'B  
if(nFileLength == -1) Y7-*2"!  
{ ~fBex_.o*  
System.err.println("File Length is not known!"); INOH{`}Ew  
} Q2q|*EL  
else if(nFileLength == -2) 6zuze0ud  
{ ^dh=M5xz)  
System.err.println("File is not access!"); #7+]%;h  
} $1~c_<DN  
else 0EyAMu  
{ XYts8}y5  
for(int i=0;i<nStartPos.length;i++) :xM}gPj"  
{ A9t8`|1"%H  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); p(.N(c  
} o,J^ e_  
for(int i=0;i<nEndPos.length-1;i++) C*a,<`
  
{ Y5n>r@)m  
nEndPos = nStartPos[i+1]; r4EoJyt  
} E.9^&E}PG  
nEndPos[nEndPos.length-1] = nFileLength; BO"qD[S  
} X CzXS.  
} [NL -!  
hl**zF  
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//启动子线程 nW11wtiO.  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; P0)AUi  
for(int i=0;i<nStartPos.length;i++) lr0M<5d=p  
{ w]F!2b!  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 8]HY. $E  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), w]}f6VlEl  
nStartPos,nEndPos,i); ;7L;  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); C;ptir1G;  
fileSplitterFetch.start(); lQWBCJ8y  
} @C=m?7O98  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), TVYz3~m  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); :kt/$S^-  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ^;4YZwW5w  
nEndPos = " + nFileLength); 9
4y9W#  
// fileSplitterFetch[nPos.length-1].start(); fq=:h\\G  
j$mz3Yk  
_CL
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//等待子线程结束 >;7a1+`3  
//int count = 0; WU7cF81$  
//是否结束while循环 4dD2{M  
boolean breakWhile = false; [Teh*CV  
a
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FllX za)  
while(!bStop) cf\&No?-p  
{ #Skj#)I"  
write_nPos(); uRpBeH]Z"  
Utility.sleep(500); 6#v
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breakWhile = true; HD H  
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for(int i=0;i<nStartPos.length;i++) J)KnE2dw5  
{ H#`8Ey  
if(!fileSplitterFetch.bDownOver) E<k^S{  
{ {!r#f(?uT  
breakWhile = false; QvJZkGX  
break; Z0W0uP;J  
} C/)`<b(  
} OT@yPG  
if(breakWhile) >:$"a  
break; r>O|L%xpv  
bJ6p,]g  
qlvwK&W<QM  
//count++; }/"4|U  
//if(count>4) @k9Pz<ub  
// siteStop(); QAUykS8  
} tgB=vIw?3  
a ea0+,;  
*uU4^E(  
System.err.println("文件下载结束！"); ai9  
} "k, K~@}  
catch(Exception e){e.printStackTrace ();} LQ>$>A(  
} xl,ryc3J  
[<S^c[47U  
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//获得文件长度 \Z'/+}^h  
public long getFileSize() }*Zo6{B-  
{ _Jy,yMQ^[_  
int nFileLength = -1; %6HX*_Mr&  
try{ 5*1#jiq  
URL url = new URL(siteInfoBean.getSSiteURL()); 
P5P<"  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); yW`e |!  
httpConnection.setRequestProperty("User-Agent","NetFox"); bl$j%gI%,  
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7_%2xewV|  
int responseCode=httpConnection.getResponseCode(); Fv@tD4I>  
if(responseCode>=400) ,Z5Fea  
{ 3.FR C  
processErrorCode(responseCode); 7UDq/:}Fo  
return -2; //-2 represent access is error :q;R6-|.  
} rKT)!o'  
ib; yu_  
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String sHeader;
}<&d]N  
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for(int i=1;;i++) Bj=@&;  
{ C=yD3mVz  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); W0|_]"K-  
//Utility.log(in.readLine()); 2`E!|X  
sHeader=httpConnection.getHeaderFieldKey(i); 6Hl<,(vn  
if(sHeader!=null) %l;*I?0H  
{ _Fxe|"<^  
if(sHeader.equals("Content-Length")) #h{Nz/h+  
{
2NYi-@mr  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); F1J#Y$q~L  
break; 4i`S+`#  
} dk8y>uLr_  
} 5QOZ%9E&M  
else m3luhGn  
break; LyV#j>gD  
} C#h76fpH  
} nzWQQra|?  
catch(IOException e){e.printStackTrace ();} XECikld>  
catch(Exception e){e.printStackTrace ();} 3A d*
,>!  
u uSHCp  
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Utility.log(nFileLength); vbedk+dd?A  
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return nFileLength; 6&mWIk^VC  
} +[_gyLN<5b  
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ET3,9+Gj  
//保存下载信息（文件指针位置） /k) NP  
private void write_nPos() l@#b;M/  
{ $YPQC  
try{ F  "!`X#  
output = new DataOutputStream(new FileOutputStream(tmpFile)); F'XlJ M  
output.writeInt(nStartPos.length); ~T7\8
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for(int i=0;i<nStartPos.length;i++) w~]}
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{ 9>I
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// output.writeLong(nPos); w0aHEvH/  
output.writeLong(fileSplitterFetch.nStartPos); Bu':2"7  
output.writeLong(fileSplitterFetch.nEndPos); %uW<  
} B6uf;Yc  
output.close(); v|>BDN@,6  
} ah>Dqb*  
catch(IOException e){e.printStackTrace ();} -: C[P  
catch(Exception e){e.printStackTrace ();} bje'Oolc  
} f)WPOTEY  
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//读取保存的下载信息（文件指针位置） ,rXW`7!2  
private void read_nPos() IN>TsTo  
{ L^&do98  
try{ 0oQ/J:  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ^T=5zqRD  
int nCount = input.readInt(); S~}$Ly@  
nStartPos = new long[nCount]; N!Rt;Xm2@  
nEndPos = new long[nCount]; (Y&R0jt  
for(int i=0;i<nStartPos.length;i++) 7@3M]5:3g  
{ 31H|?c
g<  
nStartPos = input.readLong(); -)<JBs>  
nEndPos = input.readLong(); b\H/-7<  
} ;>sq_4_  
input.close(); e_\SSH@tw  
} =y`-sU Hx  
catch(IOException e){e.printStackTrace ();} p{
w}  
catch(Exception e){e.printStackTrace ();} /\Jc:v#Q  
}
)_WH#-}  
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bXk:~LE  
private void processErrorCode(int nErrorCode) zR_9D}  
{ 9[B<rz  
System.err.println("Error Code : " + nErrorCode); L>eQ*311  
} @:I\\S@bN  
i_'|:Uy*F  
X*(gT1"
t  
//停止文件下载 2nVuz9h  
public void siteStop() bwv/{3G,Ys  
{ HrM)jC<~  
bStop = true; `1}HWLBX.  
for(int i=0;i<nStartPos.length;i++) "87O4 #$  
fileSplitterFetch.splitterStop(); f'8B[&@L  
$@XPL~4  
sqgD?:@J  
} 6yV5Yjs  
} }?\#_BCjx(  
//负责部分文件的抓取 ?
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**FileSplitterFetch.java ^d5gz0d  
*/ f]O5V$!RuE  
package NetFox; T9&,v<f  

E,"b*l.  
LbLbJ{68  
import java.io.*; /1s9;'I  
import java.net.*; ^Y1AeJ$L  
7=9A_4G!  
A=\'r<:  
public class FileSplitterFetch extends Thread { VuYWb)@  
4DG 9`5.  
3(Hj7d7'}  
String sURL; //File URL 3M`hn4)K  
long nStartPos; //File Snippet Start Position dK-  ^  
long nEndPos; //File Snippet End Position #L).BM  
int nThreadID; //Thread's ID 9OO0Ht4j  
boolean bDownOver = false; //Downing is over KBUAdpU8  
boolean bStop = false; //Stop identical Gx~"iM  
FileAccessI fileAccessI = null; //File Access interface -Ihn<<uE?  
=X%R*~!#Of  
Q9Xmb2LN  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException +w_MSj#P  
{ 8xeun~e"vS  
this.sURL = sURL; N`L' 4v)  
this.nStartPos = nStart; tOlzOBzR  
this.nEndPos = nEnd; &j wnM  
nThreadID = id; !Ed<xG/  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 t6H2tP\AS  
} hCOy\[2$  
pXh^M{.  
S|=rF<]my  
public void run() hz>yv@1  
{ A+
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while(nStartPos < nEndPos && !bStop) 
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{ ?L~=Z\H  
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iX9[Q0g=oQ  
try{ =."WvBKg  
URL url = new URL(sURL); ^0,&R\e+  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); `)gkkZ$)j  
httpConnection.setRequestProperty("User-Agent","NetFox"); [K|>s(Sf*  
String sProperty = "bytes="+nStartPos+"-"; 8zB+%mcF  
httpConnection.setRequestProperty("RANGE",sProperty); +-KRp1qq  
Utility.log(sProperty); tr67ofld|  
/n<Ncf  
V=8{CmqT  
InputStream input = httpConnection.getInputStream(); 4)>\rqF+v  
//logResponseHead(httpConnection); 5
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#\!hBL @b  
byte[] b = new byte[1024]; *z;N  
int nRead; fAA@ziKg  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) #D*J5k>2  
{ xr7<(:d  
nStartPos += fileAccessI.write(b,0,nRead); fU){]YP  
//if(nThreadID == 1) 9Av- ;!]  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); :N'[
de  
} `X]2iz
 
#.t$A9'  
t BXsWY{  
Utility.log("Thread " + nThreadID + " is over!"); )*QTxN  
bDownOver = true; PTV`=vtj  
//nPos = fileAccessI.write (b,0,nRead); 9[]"%6  
} V~^6 TS(  
catch(Exception e){e.printStackTrace ();} bU +eJU_%  
} H
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} ]C:Ifh~  
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//打印回应的头信息 r3bvuq,6$  
public void logResponseHead(HttpURLConnection con) gSo(PW)  
{ qZ]VS/5A  
for(int i=1;;i++) z(#hL-{c  
{ k~EPVJh"  
String header=con.getHeaderFieldKey(i); DDCQAf  
if(header!=null) l$_+WC*wp  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); RlPByG5K  
Utility.log(header+" : "+con.getHeaderField(header)); "l;8 O2;g  
else YV!V9  
break; EQ`t:jc{  
} 7~9f rW<K  
} s\1_-D5]Z  
s/&]gj"  
#3[b|cL  
public void splitterStop() umn~hb5O  
{ 9PfU'm|
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bStop = true; f?I *`~k  
} D\&y(=fzf  
{EHG |  
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} tNf" X!  
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/* >"{zrwNq  
**FileAccess.java Gv3Fg[MA@c  
*//文件访问(定位，写) [cAg'R6  
package NetFox; X35U!1Y\  
import java.io.*; Sg
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public class FileAccessI implements Serializable{ x#VUEu]8  
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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 17 iq  
RandomAccessFile oSavedFile; _%%"Y}  
long nPos; a-2 {x2O  
5&K
n #  
]+7c1MB(5  
public FileAccessI() throws IOException n k3lC/f  
{ ]H7Mx\  
this("",0); "(VcYQ+  
} (,y/nc=GN  
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)#B
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public FileAccessI(String sName,long nPos) throws IOException $s!meg@s  
{ Dx)XC?'xO  
oSavedFile = new RandomAccessFile(sName,"rw"); 5FKd{V'  
this.nPos = nPos; -s "$I:v  
oSavedFile.seek(nPos); ; O0rt1  
} ^i1:PlW]  
B;_3IHMO  
hkI);M+@6  
public synchronized int write(byte[] b,int nStart,int nLen) ^C|9K>M  
{ >iJuR.:OO  
int n = -1; J :(\o=5 5  
try{ gP%!  
oSavedFile.write(b,nStart,nLen); 1\{F.v  
n = nLen; N)Kr4GC  
} ~riw7"  
catch(IOException e) R?SHXJ%'  
{ =(\!,S'  
e.printStackTrace (); nQmYeM  
} y@JYkp>I  
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bOKNWI  
return n; *4y r7~S5  
} nP31jm+A  
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NZP,hAUK,  
} "r+<=JU>OV  
u;}B4Rx
  
J< M;vB)  
/* V1;-5L75  
**SiteInfoBean.java ;d40:q<  
*/ ]Jqe)o  
package NetFox; $@wkQ%  
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public class SiteInfoBean { V|7CYkB8  
v%[mt`I  
!6C d.fpWL  
private String sSiteURL; //Site's URL cqp#1oM4M  
private String sFilePath; //Saved File's Path yqwr0yDAl  
private String sFileName; //Saved File's Name Wz]S+IpY  
private int nSplitter; //Count of Splited Downloading File $ 1ZY Vw  
X9HI@M]h  
v2V1&-
  
public SiteInfoBean() ,V?,I9qf  
{//nSplitter的缺省值为5 C-Z,L#  
//default value of nSplitter is 5 swrd  
this("","","",5); uX[

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} 3>6o=7/PU  
%?jf.p*kY  
< r~Tj  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) .
/'n2$
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{ _#:1Axx1  
sSiteURL= sURL; 9h{G1XL  
sFilePath = sPath; ,+&j/0U  
sFileName = sName; 7SCI_8`  
this.nSplitter = nSpiltter; X'm2uOEj  
9@06]EI_  
-,&Xp>u\  
} f]}F_]  
w6_}] &F  
NL 37Y{b  
public String getSSiteURL() /v[-KjTj7  
{ 0bE_iu>f'  
return sSiteURL; j*{bM{~T<  
} V
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J"y@n~*0  
[>;O'>  
public void setSSiteURL(String value) 6D],275`J  
{
~CA+'e%~~  
sSiteURL = value; ; F=_ozWV*  
} ]Gr'Bt/  
&ly[mBP~  
d:D2[  
public String getSFilePath() WxFjpJt  
{ EB#z\  
return sFilePath; c.fj[U|j  
} NmQ]qv  
AZa3!e/1  
s@$AYZm_  
public void setSFilePath(String value) L2qF@!Yy=  
{ j*5VJ:  
sFilePath = value; Ut+mm\7  
} D&shrKFx  
-n9e-0  
)~`zjVx_  
public String getSFileName() r!#3>
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{ Vr*t~M>  
return sFileName; _KFKx3<m!  
} F,sT[C  
)nY/
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public void setSFileName(String value) EVf'1^f  
{ J
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sFileName = value; 3X:F9x>y  
} G<-.{Gx)  
^tah4QmUA  
_5zR!|\^  
public int getNSplitter() :.dQY=6I  
{ g@QpqrT  
return nSplitter; bYtF#Y  
} hCmOSDym  
$H#
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/$n${M5!  
public void setNSplitter(int nCount) 9qpH 8j+  
{ oI>;O#  
nSplitter = nCount; J=$v+8&.  
} te|VKYN%}[  
} {b?)|@)is  
)6(mf2&  
4
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/* yaf2+zV*  
**Utility.java IOA{lN6  
*/ MwuH.# Ez  
package NetFox; {?C7BClB  
Ev()2 80  
yqK82z5U*R  
public class Utility { r=9*2X#  
~7ArH
9k.  
{<GsM  
public Utility() !yxb<  
{ #NqA5QR  
}$7Hf+G  
f5G17: Q  
} #C+0m`  
GL/\uq  
//线程睡眠 PY^Yx$t9  
public static void sleep(int nSecond) @1>83-p"X  
{ Kg.E~  
try{ nhIITfJJ  
Thread.sleep(nSecond); =v_ju;C=  
} %|;^[^7+}t  
catch(Exception e) tHGK<rb  
{ 89L-k%R  
e.printStackTrace (); nK:39D$(  
} 04(h!@!g:  
} b*bR<|dTj  
^=tyf&"  
//日志 1D*e
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public static void log(String sMsg) S`J_}>  
{ ]Rw,5\0  
System.err.println(sMsg); _-D(N/  
} c`i
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(Q@m;i>  
lFB Ka ,6  
public static void log(int sMsg) ;BI{v^()s  
{ D.HAp+lx  
System.err.println(sMsg); ]$z~;\T  
} {}>"f]3  
} =U^B,q  
vbSz&+52;  
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/* '- Z4GcL  
**TestMethod.java >`6^1j(3  
*/ %~6+=*(\  
package NetFox; OyH
:  
02SUyv(Mt  
r"0nUf*og:  
public class TestMethod { V-jo2+Y5=  
D$j`+`  
-5E<BmM  
public TestMethod() 6/GhQ/T%D  
{ ///xx/weblogic60b2_win.exe Sm-nb*ZyC  
try{ KYlWV<sR  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); YGxdYwBwf  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); wv1?v_4  
SiteFileFetch fileFetch = new SiteFileFetch(bean); oiklRf  
fileFetch.start(); b?r0n]  
} 0m?ul%=  
catch(Exception e){e.printStackTrace ();} @m(\f  
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>f_D|;EV  
} wl!'Bck=  
,,@_r&f:  
X-t4irZ)  
public static void main(String[] args) dso\+s  
{ 'dBzv>ngD  
new TestMethod(); | WDX@Q  
} E6n;_{Se/S  
} 8y+Gvk:  
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