http断点续传简单实现（java)

/* CC,f*I  
**SiteFileFetch.java X 

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*/ `]T#uP<u  
package NetFox; >GV(\In  
import java.io.*; G(Ky7SZ  
import java.net.*; 6g6BE^o\  
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public class SiteFileFetch extends Thread { @,9cpaL3  
 K}OY!|  
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SiteInfoBean siteInfoBean = null; //文件信息Bean [$x&J6jF.  
long[] nStartPos; //开始位置 K{vn[}  
long[] nEndPos; //结束位置 l`mNOQ@}'  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 3hD
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long nFileLength; //文件长度 >Q-"-X1  
boolean bFirst = true; //是否第一次取文件 (q 0wV3Qv  
boolean bStop = false; //停止标志 o`{@':%D`  
File tmpFile; //文件下载的临时信息 R=co2 5  
DataOutputStream output; //输出到文件的输出流 ~LG<Uu  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） # fe%E.  
public SiteFileFetch(SiteInfoBean bean) throws IOException O]1aez[  
{ 141G~@-  
siteInfoBean = bean; 1SwKd*aRR?  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); }2!=1|}  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); xIb"8,N  
if(tmpFile.exists ()) \@eaSa  
{ ]Jum(1Bo  
bFirst = false; N!Cy)HnS\w  
read_nPos(); a49xf^{1"i  
} 7`pK=E}+  
else #Aver]e
K  
{ TGSkJ 1Lx  
nStartPos = new long[bean.getNSplitter()]; G@=H=' :~  
nEndPos = new long[bean.getNSplitter()]; ETMF.-P  
} ?E6C|A$I  
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} SKdh!*G  
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;  
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public void run() Fs 95^T  
{ mNDd>4%H_  
//获得文件长度 VQ(l=k:}2  
//分割文件 )Zbrg~-@  
//实例FileSplitterFetch \ 0J&^C  
//启动FileSplitterFetch线程 ?(2^lH~6h  
//等待子线程返回 .?NraydwV  
try{ )ePQN~#K}  
if(bFirst) 6b7SA,  
{ YkJnZ_k/P  
nFileLength = getFileSize(); LO@='}D=  
if(nFileLength == -1) ]dU/;8/%  
{ gQ;1SY!  
System.err.println("File Length is not known!"); -8%[7Z]  
} (;T g1$  
else if(nFileLength == -2) (-bLP
 
{ xL#UMvZ>;h  
System.err.println("File is not access!"); ]R%+  
} 1@6FV x  
else u~7 ,v  
{ fb;y*-?#  
for(int i=0;i<nStartPos.length;i++) i8+[-mh  
{ cms9]  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); o>?#$~XNv  
} >u/ T`$  
for(int i=0;i<nEndPos.length-1;i++) tv\_& ({  
{ oJln"-M1nx  
nEndPos = nStartPos[i+1]; $9PscubM4  
} qrt2BT)  
nEndPos[nEndPos.length-1] = nFileLength; [~UCYYl  
} "+k^8ki  
} w^N3Ma  
SXF~>|h5<  
}MCJ$=5  
//启动子线程 :}{,u6\  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; v#`7,::  
for(int i=0;i<nStartPos.length;i++) Api<q2@R  
{ s:f%=4-7  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), {wy#HYhv  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), I]vCra  
nStartPos,nEndPos,i); _X"G(  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); H
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fileSplitterFetch.start(); -JwwD6D  
} D
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// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), T(4OPiKu  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); *fg|HH+i  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", H=1Jq  
nEndPos = " + nFileLength); ~uRL+<.c  
// fileSplitterFetch[nPos.length-1].start(); SQ0t28N3h  
f>kW\uC  
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//等待子线程结束 MB:*WA&  
//int count = 0; wD|I^y;  
//是否结束while循环 d^W1;0  
boolean breakWhile = false; =*Ru2  
._A@,]LS}  
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while(!bStop) Kh,zp{  
{ K! e5
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write_nPos(); Yj/[I\I"m  
Utility.sleep(500); Z&[_8Y5j  
breakWhile = true; i3v|r 0O~L  
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for(int i=0;i<nStartPos.length;i++) LktH*ePO  
{ 9W+RUh^W  
if(!fileSplitterFetch.bDownOver) Vb$
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{ pxgVYr.  
breakWhile = false; =&YhA}l\O  
break; f'28s*n  
} +:jx{*}jo  
} q{E44 eQ7F  
if(breakWhile) -lDAxp6p  
break; wOU\&u|
 
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//count++; 5*P+c(=  
//if(count>4) O\&[|sGY{  
// siteStop(); " _{o}
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} &/-^D/ot  
~]LkQQ'  
N`1W"Rx!  
System.err.println("文件下载结束！"); >jH%n(TcC  
} {Xw6p  
catch(Exception e){e.printStackTrace ();} ^p}|""\j  
} U2TR>0l  
iB0#Z
_  
/ij)[WK@  
//获得文件长度 m&!4*D  
public long getFileSize() 5wgeA^HE2y  
{ \#O}K  
int nFileLength = -1; Q-7C'|  
try{ eemw I  
URL url = new URL(siteInfoBean.getSSiteURL()); jSc!"Trl]  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); U\~9YX8  
httpConnection.setRequestProperty("User-Agent","NetFox"); !wNj;S
T*  
.m/$ku{/J  
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int responseCode=httpConnection.getResponseCode(); >xB[k-C4  
if(responseCode>=400) _ 0g\g~[  
{ %ok??_}$}q  
processErrorCode(responseCode); 3I):W9$Qp  
return -2; //-2 represent access is error {$H-7-O$  
} %TUvH>;0  
t'{IE!_  
RF$2p4=[  
String sHeader; Z\. n6  
ckhU@C|=*  
-{O>'9'1A  
for(int i=1;;i++) hw9qnSeRy  
{ PqDff
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//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); e:uk``\  
//Utility.log(in.readLine()); 8
;\  
sHeader=httpConnection.getHeaderFieldKey(i); |S0nR<x-M  
if(sHeader!=null) )F,IPAA#  
{ $LkTu  
if(sHeader.equals("Content-Length")) [~&yLccN  
{ `G0GWh)`x  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); s:ZYiZ-  
break; DElrY)3O.  
} ,*MAteD  
} !> 2kH  
else hteAuz4H  
break; EJ@&vuDd$  
} 0Fc^c[  
} 9Rd&Jq^  
catch(IOException e){e.printStackTrace ();} pB5#Ho>S  
catch(Exception e){e.printStackTrace ();} BL[N  
``:+*4e9  
6m$lK%P{1  
Utility.log(nFileLength); L'L[Vpx  
j[Q9_0R~lR  
uEui{_2$  
return nFileLength; z)Gd3C  
} u8Ak2:   
wG@f~$  
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//保存下载信息（文件指针位置） fHd|tl  
private void write_nPos() F?+\J =LT  
{ {|{;:_.>  
try{ m"/ o4  
output = new DataOutputStream(new FileOutputStream(tmpFile)); qd<-{  
output.writeInt(nStartPos.length); fW=
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for(int i=0;i<nStartPos.length;i++) LE}V{%)xD  
{ %EH{p@nM&-  
// output.writeLong(nPos); .L@gq/x)  
output.writeLong(fileSplitterFetch.nStartPos); zQ~ax!}R  
output.writeLong(fileSplitterFetch.nEndPos); Y?v{V>
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} 572{DC&T  
output.close(); _)kTlX:,  
} l0w<NZF  
catch(IOException e){e.printStackTrace ();} uL{CUt  
catch(Exception e){e.printStackTrace ();} 4G2iT+X-  
} )_olJCdaP^  
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//读取保存的下载信息（文件指针位置） alH6~  
private void read_nPos() 6,cJ3~!48  
{ 4$+1&
+@ ]  
try{ U8zCV*ag  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); b4&l=^:e=  
int nCount = input.readInt(); WZM  
nStartPos = new long[nCount]; FrC)2wX  
nEndPos = new long[nCount]; H
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for(int i=0;i<nStartPos.length;i++) q ;"/i*+3  
{ \q@Co42n\  
nStartPos = input.readLong(); ezb*tN!  
nEndPos = input.readLong(); }jg1..)"<  
} ON9L+"vqv0  
input.close(); ;,/4Ry22j-  
} uJ`:@Z^J  
catch(IOException e){e.printStackTrace ();} " GY3sam  
catch(Exception e){e.printStackTrace ();} o3$dl`'  
} 9ZNzC i!  
wk#cJ`wG;  
n^|SN9_r  
private void processErrorCode(int nErrorCode) iPdS>ee  
{ WjguM  
System.err.println("Error Code : " + nErrorCode); [y~kF?a  
} >n3ig~0d  
sJ{r+wY  
EU7nS3K)O~  
//停止文件下载 Ma4eu8  
public void siteStop() .k$Yleg  
{ 7g$*K0m`  
bStop = true; 0V?7'Em  
for(int i=0;i<nStartPos.length;i++) =ld!=II  
fileSplitterFetch.splitterStop(); %(|-+cLW+  
_Wq;bKG  
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} d3\KUR^  
} 2}XxRJ0   
//负责部分文件的抓取 +IMt$}7[  
**FileSplitterFetch.java Lr9E02  
*/ PjofW%7F  
package NetFox; %k<+#j6ZH  
fw VI%0C@  
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import java.io.*; ?9%$g?3Z  
import java.net.*; U{qwhz(  
ii&ckg>]z  

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public class FileSplitterFetch extends Thread { wwv+s~(0  
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String sURL; //File URL );h  
long nStartPos; //File Snippet Start Position 7nB
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long nEndPos; //File Snippet End Position &bGf{P*Da  
int nThreadID; //Thread's ID 'Fc$?$c\  
boolean bDownOver = false; //Downing is over :wEy""*N0  
boolean bStop = false; //Stop identical sgnc$x"  
FileAccessI fileAccessI = null; //File Access interface 6Eus_aP  
EG|_YW7  
8)2M%R\THn  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ta<8~n^?  
{ kkW}:dBl  
this.sURL = sURL; 6oFA=CjU{  
this.nStartPos = nStart; \%9QE  
this.nEndPos = nEnd; Bz|/TV?X(  
nThreadID = id; ;U$Rd,T4S  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 j<6+p r  
}
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yu
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public void run() pe>?m^gz[  
{ }:u-l3e  
while(nStartPos < nEndPos && !bStop) ur7S K(#  
{ +G\i$d;St  
u#`51Hr
$  
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try{ \KS.A 4  
URL url = new URL(sURL); *=!r|UdB.  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); :Rnwyj])  
httpConnection.setRequestProperty("User-Agent","NetFox"); ~w9`l8/0  
String sProperty = "bytes="+nStartPos+"-"; V6h8+|hK  
httpConnection.setRequestProperty("RANGE",sProperty); ]"?<y s  
Utility.log(sProperty); /{
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d(@ ov^e-  
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InputStream input = httpConnection.getInputStream(); rZ)7(0BBs  
//logResponseHead(httpConnection); B2KBJ4rI[1  
@?;)x&<8?3  
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byte[] b = new byte[1024]; e\f\CMb  
int nRead; Z c#Jb  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Y^U^yh_!^  
{ vS[\j  
nStartPos += fileAccessI.write(b,0,nRead); B-"F67:  
//if(nThreadID == 1) =Zsxl]h   
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); U!K#g_}  
} dWe
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Utility.log("Thread " + nThreadID + " is over!"); M'oZK  
bDownOver = true; .2_
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//nPos = fileAccessI.write (b,0,nRead); Ul'H(eH.v  
} -w8?Ur1x:  
catch(Exception e){e.printStackTrace ();} ]2ycJ >w  
} Fg}t{e]3a  
} -)KNsW  
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I3izLi
 
//打印回应的头信息 \" m&WFm  
public void logResponseHead(HttpURLConnection con) tB4yj_ZF  
{ tw.z5  
for(int i=1;;i++) ~?)y'?  
{ -/*VR$c  
String header=con.getHeaderFieldKey(i); <]|!quY<*  
if(header!=null) tK'9%yA\  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); qK~]au:C  
Utility.log(header+" : "+con.getHeaderField(header)); (v:8p!QN  
else b^(
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break; : t75iB=  
} $BB^xJ\O  
} gp H@F
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%.Kr`#lCr  
public void splitterStop() jIHY[yDT  
{ *YX:e@Fm.a  
bStop = true; g2 mq?q(g  
} ed3wj3@  
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} /oGaA@#+  
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+UTBiB R  
/* %zDi|WZ  
**FileAccess.java D`.\c#;cN  
*//文件访问(定位，写) ,:V[H8 ?  
package NetFox; D4
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import java.io.*; /5 OQ0{8p  
!ZCxi  
4<5*HpW  
public class FileAccessI implements Serializable{ Eq=JmO'gHs  
<KStlfX  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 o>m*e7l,  
RandomAccessFile oSavedFile; kKDf%=  
long nPos; f3h]t0M  

/7Q9(}  
Z7?\ >4V  
public FileAccessI() throws IOException sqRvnCD!  
{ /;u=#qu(E-  
this("",0); E5*pD*#  
} NpbZt;%t  
mQ<Vwx0  
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public FileAccessI(String sName,long nPos) throws IOException #H5+8W  
{ !2/o]_K@+  
oSavedFile = new RandomAccessFile(sName,"rw");
(#qQ;ch  
this.nPos = nPos; #&z'?x^a  
oSavedFile.seek(nPos); `dl^)
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} zcio\P=^|B  
^$rqyWZYp  
Fa{[kJ8z  
public synchronized int write(byte[] b,int nStart,int nLen) xsvJjs;=  
{ li#ep?5h^  
int n = -1; *w6F0>u  
try{ q!Z{qt*`um  
oSavedFile.write(b,nStart,nLen); b/E3Kse?  
n = nLen; bcAk$tA2  
} {Wr5F9q  
catch(IOException e) (tiE%nF+  
{ ?-<>he  
e.printStackTrace (); ="AaC!E,W  
}
<" 0b8 Z  
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e YiqTWn:  
return n; iWkC:fQz  
} gTdr  
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} 1>umf~%Wa  
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/* y3P4]sq  
**SiteInfoBean.java Nkn2\w  
*/ hdH3Jb_hl(  
package NetFox; /U0,%  
s;[WN.  
SXNde@% {  
public class SiteInfoBean { |>wGl  
02YmV%  
\9}DAM_  
private String sSiteURL; //Site's URL m.lzkS]P  
private String sFilePath; //Saved File's Path 4lwoTGVZj  
private String sFileName; //Saved File's Name yMpZ-b$*~  
private int nSplitter; //Count of Splited Downloading File *0_Q0SeE,o  
v"_E0 3!  
T5dnj&N ]  
public SiteInfoBean() g#G ]}8C  
{//nSplitter的缺省值为5 Ian+0 ?`
e  
//default value of nSplitter is 5 zT>BC}~.b  
this("","","",5); P]2V~I/X  
} F4IU2_CnPD  
RP k'1nD  
%Y9CZRY9  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) FJn.V1  
{ s|k&@
jH)  
sSiteURL= sURL; :4r*Jju<V  
sFilePath = sPath; [n3@*)q's  
sFileName = sName; !%N@>[  
this.nSplitter = nSpiltter; 1-|aeJ  
9|m:2["|?  
WYIv&h<h"  
} MHA_b^7?  
Q07&7SH_  
iV!V!0- @  
public String getSSiteURL() RNt9Qdr4y  
{ DHZ`y[&}|N  
return sSiteURL; }L=Qp
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} Xv+,Z<>iQ  
"/%o'Fq  
,Kt51vGi  
public void setSSiteURL(String value) pnXwE-c_  
{ ` }B,w-,io  
sSiteURL = value; NPDMv |4  
} 5<P6PHdY  
5=8t<v1Bn  
P(
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public String getSFilePath() ex66GJQe1  
{ {BgJ=0g?  
return sFilePath; d\25  
} k *>"@  
Pc<0kQg  
RiFUa $  
public void setSFilePath(String value) :>F3es`  
{ R`B} T<*
  
sFilePath = value; $EzWUt  
} U2v;GIo$yU  
3eB)X2~   
>]uu?!PU  
public String getSFileName() E()%IC/R  
{ ^x_$%8  
return sFileName; ae](=OQ  
} G,<l}(tEG  
e3?z^AUXm  
WBb*2  
public void setSFileName(String value) (H\ `/%Bp  
{ Xz9[0;Q  
sFileName = value; oxdX2"WwU  
} cDK)zD  
wuW{2+)B  
h4+*ssnYV  
public int getNSplitter() ;>S|?M4GZ  
{ y~su1wUp  
return nSplitter; 4YR{ *  
} }D.\2x(J  
` U-vXP  
Et0)6^-v  
public void setNSplitter(int nCount) 
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{ M?GkHJ%!  
nSplitter = nCount; p#_5w  
} X{<taD2~  
} ayQeT  
{m@tt{%  
c((bUjS'=Y  
/* 6As%<g=  
**Utility.java g/i%XTX>  
*/ $15H_X*!  
package NetFox; pjs4FZ`Pd;  
p1K]m>Y{?  
M{)&SNI*C  
public class Utility { Y=g]\%-PB  
H8=:LF  
:@eHV=|+>  
public Utility() Tku6X/LF  
{ E31YkD.A  
Z0<s -eN:  
L]u^$=rI  
} 1iNMgA  
#TC}paIpj  
//线程睡眠 8R:Glif  
public static void sleep(int nSecond) GN:|b2 "  
{ 29VX-45  
try{ Q'JK *.l  
Thread.sleep(nSecond); /oLY\>pD  
} f-ceDn  
catch(Exception e) /y6f~F  
{ &I(\:|`o  
e.printStackTrace (); D.|r [c  
} I|qhj*_C  
} (DS"*4ty  
*Ms"{+C  
//日志 xI~AZ:m  
public static void log(String sMsg) {K6Z.-.`  
{ 4*Gv0#dga  
System.err.println(sMsg); L
F} d  
} :FfEjNil  
K"&^/[vMB  
Xo]2iQy  
public static void log(int sMsg) WSN^iDS
 
{ dUt4] ar  
System.err.println(sMsg); Dw
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} k0#s{<I]E  
} '3Q~y"C+4  
~zG)<S"q  
Xt$P!~Lu  
/* @"1Z;.S8V  
**TestMethod.java c5b}q@nH  
*/  s2wDJ|  
package NetFox; / o I 4&W  
ViMl{3  
)KVr2y;RF  
public class TestMethod { FI.F6d)E$  
9==4T$nM[  
%7P]:G+Y\  
public TestMethod() nqo1+OR  
{ ///xx/weblogic60b2_win.exe _SOwiz  
try{ S50}]5K  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); -,T!/E  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 0B!(i.w  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 5`+9<8V  
fileFetch.start(); /4 OmnE;  
} 7aKI=;60.  
catch(Exception e){e.printStackTrace ();} [fV"tf;  
law
$LL  
|N"K83_pr  
} CfP-oFHoQ  
}2"W0ZdWD  
2,`X@N`\  
public static void main(String[] args) /|P{t{^WM  
{ EPH" 5$8  
new TestMethod(); 58HA*w  
} oYTLC@98}  
} v @0G^z|  
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