http断点续传简单实现（java)

/* 4&LoE~  
**SiteFileFetch.java U^X8{,8O  
*/ #8jH_bi  
package NetFox; \it<]BN  
import java.io.*; TDQh^Wo  
import java.net.*; DK;/eZe  
&U/~*{  
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public class SiteFileFetch extends Thread { ?|9$o/Q}  
*`V-zD  
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SiteInfoBean siteInfoBean = null; //文件信息Bean w]0jq U6  
long[] nStartPos; //开始位置 \ow0Y>  
long[] nEndPos; //结束位置 [f'DxZF-  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 +#<"o#gZ  
long nFileLength; //文件长度 )p;gm`42oY  
boolean bFirst = true; //是否第一次取文件 f?C !
Br}  
boolean bStop = false; //停止标志 wbId}!
 
File tmpFile; //文件下载的临时信息 MXhRnVz"W  
DataOutputStream output; //输出到文件的输出流 Pjff%r^  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） D r$N{d  
public SiteFileFetch(SiteInfoBean bean) throws IOException pf`li]j'V  
{ |KC
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siteInfoBean = bean; Lsozl<@  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); MY[
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tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info");
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if(tmpFile.exists ()) *H RxC  
{ :PaFC{O)*  
bFirst = false; P5P<-T{-c  
read_nPos(); b\\?aR |  
} {:enoV"  
else y!^RL,HIL  
{ ':w6{b  
nStartPos = new long[bean.getNSplitter()]; c~|/,FZU'  
nEndPos = new long[bean.getNSplitter()]; <`9:hPp0  
} &,&oTd.  
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} ;@d<*  
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public void run() i
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{ MOmp{@  
//获得文件长度 [*>@hx  
//分割文件 pp[? k}@  
//实例FileSplitterFetch I|O~F e.  
//启动FileSplitterFetch线程 .[Sv|;x"E  
//等待子线程返回 95
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try{ 73.o{V  
if(bFirst) Z?hBn`.  
{ ._tv$Gd@k  
nFileLength = getFileSize(); }u+R,@l/  
if(nFileLength == -1) +-~;?wA  
{ (lPNMS|V  
System.err.println("File Length is not known!"); f3l >26  
} xHr  
else if(nFileLength == -2) 
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{ t8)Fkx#8}  
System.err.println("File is not access!"); l2`8]Qr   
} {2:H
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else d=4MqX r  
{ esu6iU@  
for(int i=0;i<nStartPos.length;i++) a5)[?ol  
{ v*BA\&  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); w6"LHy[  
} ?I@3`?'  
for(int i=0;i<nEndPos.length-1;i++) WAdl@){  
{ @e0Q+
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nEndPos = nStartPos[i+1]; s_*eX N  
} ^3yjE/Wi"  
nEndPos[nEndPos.length-1] = nFileLength; X7 ZaQ .  
} !7^He3  
} Xs`:XATb/  
y=j[v},4  
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//启动子线程 R\Q%
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; !eTS PM  
for(int i=0;i<nStartPos.length;i++) h.Dk>H_G  
{ c,~44Z  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Jb$z(?S  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), YI|Gpq  
nStartPos,nEndPos,i); yED^/=\)}  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); q-3KF  
fileSplitterFetch.start(); :<v$vER,&  
} O#U
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// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Sd\@Q% }o\  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); p.\KmEx  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", <V8i>LBlz  
nEndPos = " + nFileLength); )UdS(Bj  
// fileSplitterFetch[nPos.length-1].start(); .>nd@oU  
s+w<!`-  
=!c+|X
`  
//等待子线程结束 [:=[QlvV  
//int count = 0; <&Uk!1Jd  
//是否结束while循环 QO>*3,(H,q  
boolean breakWhile = false; [;2:lbPx  
KN`z68c4
L  
@/u`7FO$&  
while(!bStop) xq)/QR  
{ y,>m#6hx#  
write_nPos(); 9M=K@a  
Utility.sleep(500); MGz> ,c^wW  
breakWhile = true; qR<DQTO<  
? 7EVmF  
B<&_lG0sS  
for(int i=0;i<nStartPos.length;i++) >y~_Hh(TSL  
{ [-gKkOT8E  
if(!fileSplitterFetch.bDownOver) 7EO&:b]  
{ C
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breakWhile = false; ;$E[u)l  
break; n6Zx0ad?  
} )89jP088V  
} [L(l++.z  
if(breakWhile) (R<4"QbE  
break; gWo~o]f  
?t42=nvf  
uPXqTkod  
//count++; _fCHj$I*]  
//if(count>4) P0(~~z&%[  
// siteStop(); LD~'^+W  
} P$ef,ZW"  
IR8&4qOs  
'uzv\[  
System.err.println("文件下载结束！");
(NC>[  
} #jx?uS  
catch(Exception e){e.printStackTrace ();} <'_GQM`G  
} jFTV\|C  
pe%)G6@G  
;Hb[gvl  
//获得文件长度 BQ:Kx_   
public long getFileSize() Kn$1W=B1.  
{ 7 aD&\?  
int nFileLength = -1; 3F}KrG  
try{ M9g\/]Io;  
URL url = new URL(siteInfoBean.getSSiteURL()); N>Y50  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); l1Q+hz5"*U  
httpConnection.setRequestProperty("User-Agent","NetFox"); yaLW(@  
f$|v0Xs  
^!F5Cz 48  
int responseCode=httpConnection.getResponseCode(); aZ>\*1
 
if(responseCode>=400) e@-Mlq)  
{
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processErrorCode(responseCode); o[[r_v_d  
return -2; //-2 represent access is error },aWCvJL  
} .^IhH|U  
7XWBI\SW  
fP1OH&Ar  
String sHeader; j~*Z7iu  
X5
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)c >B2
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for(int i=1;;i++) [H%?jTQ  
{ ~P#zhHw  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 5 t`ap  
//Utility.log(in.readLine()); V<V\0n!0  
sHeader=httpConnection.getHeaderFieldKey(i); Rw\C0'  
if(sHeader!=null) n`z+ w*  
{ T|s0qQi  
if(sHeader.equals("Content-Length")) +aw>p_\  
{ fTHun?Vn  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); [&qbc#L  
break; DGZY~(]  
} (5q%0|RzRs  
} iqednk%  
else =8~R$z%  
break; ki~y@@
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} i`KZ,   
} LJ(n?/z%  
catch(IOException e){e.printStackTrace ();} v^c<`i;  
catch(Exception e){e.printStackTrace ();} x:?a;muf  
|^PLZ>  
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Utility.log(nFileLength); 6Z7pz
tk  
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return nFileLength; ^5^}MB%  
} J,1osG<6x  
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xEiX<lguyN  
//保存下载信息（文件指针位置） %7]XW2u  
private void write_nPos() W
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{ 27a*H1iQ  
try{ e*P=2*]M  
output = new DataOutputStream(new FileOutputStream(tmpFile)); t{X?PF\>o  
output.writeInt(nStartPos.length); %[nR|a<  
for(int i=0;i<nStartPos.length;i++) ?cO8'4 bq  
{ NYjS  
// output.writeLong(nPos); o3F|#op  
output.writeLong(fileSplitterFetch.nStartPos); fi&uB9hc  
output.writeLong(fileSplitterFetch.nEndPos); Be{/2jU%  
} {M@@)27gW  
output.close(); 7rdw`  
} "X5_-l  
catch(IOException e){e.printStackTrace ();} |0L=8~M(j  
catch(Exception e){e.printStackTrace ();}
'(*&Ax  
} f]ue#O   
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o9ctJf=qn  
//读取保存的下载信息（文件指针位置） v]:+`dV  
private void read_nPos() *qPdZ  
{ `V&1]C8x  
try{ `S\zqF<  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); lMC{SfdH  
int nCount = input.readInt(); K$GRJ  
nStartPos = new long[nCount]; AfRW=&xdT  
nEndPos = new long[nCount]; ym|NT0_0  
for(int i=0;i<nStartPos.length;i++) H|;*_  
{ z.3<{-n}0i  
nStartPos = input.readLong(); <)O>MI' 4  
nEndPos = input.readLong(); %kh#{*q$  
} *;hY.EuoFz  
input.close(); |(V?,^b^ro  
} q^a|
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catch(IOException e){e.printStackTrace ();} UvxSMD:A  
catch(Exception e){e.printStackTrace ();} 76-jMcGi  
} VEj$^bpp5s  
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private void processErrorCode(int nErrorCode) 0#oBXu  
{ j8G
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System.err.println("Error Code : " + nErrorCode); EntF@ln!  
}  7%}a
y  
i;o}o*=  
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//停止文件下载 5@P%iBA4(3  
public void siteStop() UJz#QkAio  
{ 2_;]  
bStop = true; |3}5:k  
for(int i=0;i<nStartPos.length;i++)  fb\DiKsW  
fileSplitterFetch.splitterStop(); P+<BOG|m  
' .B.V?7  
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} pDu{e>S|:  
} CI`N8 f=v  
//负责部分文件的抓取 LA-_3UJx  
**FileSplitterFetch.java qmZ2d!)o  
*/ 3VmI0gsm.>  
package NetFox; b'i'GJBQ+$  
t|}O.u-&;~  
lT]=&m>  
import java.io.*; 0rD#s{?  
import java.net.*; '>@4(=I  
E
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public class FileSplitterFetch extends Thread { 8L%M<JRg~  
mN;+TN'?{  
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String sURL; //File URL g\U/&.}DN  
long nStartPos; //File Snippet Start Position hd B |#t  
long nEndPos; //File Snippet End Position dpwD8Q< U  
int nThreadID; //Thread's ID $I@GUtzjp  
boolean bDownOver = false; //Downing is over #'@ilk/.  
boolean bStop = false; //Stop identical P z ?m>>#  
FileAccessI fileAccessI = null; //File Access interface 38~PWKt  
lWWP03er!  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException xCWz\-;  
{ \fZiL!E^7  
this.sURL = sURL; c'Z:9?#5  
this.nStartPos = nStart; rK1-Mu  
this.nEndPos = nEnd; Z!6UW:&~7  
nThreadID = id; _%y4q%#  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 k[\a)WcY8  
} a2`%ghW3  
]H ~Y7\N-v  
!9;)N,  
public void run() =O!|IAe#  
{ @x1%)1  
while(nStartPos < nEndPos && !bStop) !Xj#@e  
{ 22 &'@C>  
.2.qR,"j  
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try{ S]^`woD  
URL url = new URL(sURL); { p;shs5  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 2*[QZ9U[@  
httpConnection.setRequestProperty("User-Agent","NetFox"); ~i ,"87$[  
String sProperty = "bytes="+nStartPos+"-"; 0,_b)  
httpConnection.setRequestProperty("RANGE",sProperty); ;o0#(xVz  
Utility.log(sProperty); }7ehF6  
zI^]esX!2_  
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InputStream input = httpConnection.getInputStream(); [dB$U}SEj  
//logResponseHead(httpConnection); *6Q|}b[qcD  
O0T/#<Cn!  
~`qEWvPn  
byte[] b = new byte[1024]; ^s&W>hTX:  
int nRead; u%3i0BajY  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) `&!k!FZY*  
{ T%$jWndI  
nStartPos += fileAccessI.write(b,0,nRead); ZF6c{~D  
//if(nThreadID == 1) 1@>$ Gcc  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 0K`[,
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} 9CJ(Z+;OM  
+5!&E7bcd  
\OQkZ.cU;  
Utility.log("Thread " + nThreadID + " is over!"); A
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bDownOver = true; H4:&%"j7  
//nPos = fileAccessI.write (b,0,nRead); ?>$l  
} N\NyXh$  
catch(Exception e){e.printStackTrace ();} -fy9<  
} [Wi1|]X"G  
} IXpc,l `  
jq-l5})h  
eF~dQ4RZ  
//打印回应的头信息 x
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public void logResponseHead(HttpURLConnection con) V
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{ yVX8e I  
for(int i=1;;i++) m&*JMA;^  
{ d%_OT0Ei  
String header=con.getHeaderFieldKey(i); s?2$ue&-f  
if(header!=null) \?**2{9&)  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); g^7MM
lY%  
Utility.log(header+" : "+con.getHeaderField(header)); o*5U:'=5}  
else IgIYguQ  
break; q_V0+
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} PLX>-7@  
} =-"c*^$]  
NX[4PKJ0C  
v+G=E2Lh
v  
public void splitterStop() -F@L}|  
{ aC%&U4OS  
bStop = true; E{E0Z9t7&  
} t)f-mQz)  
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} 'n;OB4  
mh.+."<)F  
Ts.wh>`  
/* 8|6 4R:  
**FileAccess.java $q$7^r@
 
*//文件访问(定位，写) i/H+xrCK  
package NetFox; C0jj(ku&  
import java.io.*; <\ `$Jx#  
GZip\S4Y  
n]}W``=7  
public class FileAccessI implements Serializable{ l12{fpm  
rV6/Tdy  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 x3 >  
RandomAccessFile oSavedFile; /w(e  
long nPos; q_kdCO{:df  
rG}\Zjn{  
qIIJ4n  
public FileAccessI() throws IOException 8CbXMT  
{ H+E$:)gN  
this("",0); \C,p
WW  
} _P?s'HH  
_8,()t'"  
|`TgX@,#9  
public FileAccessI(String sName,long nPos) throws IOException En{`@JsM  
{ 1rKy@9  
oSavedFile = new RandomAccessFile(sName,"rw"); M_g?<rK  
this.nPos = nPos; nKa$1RMO  
oSavedFile.seek(nPos); 2*w0t:Yxe  
} Dre2
J<QL  
Zf$Np50@(  
qz?mh4Oh  
public synchronized int write(byte[] b,int nStart,int nLen) M(x$xAiD  
{ b~=0[Rv  
int n = -1; t>=fTkB  
try{ &i+Ce  
oSavedFile.write(b,nStart,nLen); zk-.u}RBFG  
n = nLen; w| `h[/,  
} js iSg/  
catch(IOException e) WHXj8*]6  
{ SZaS;hhhHu  
e.printStackTrace (); [S5\#=_4S  
} gzoEUp=s  
'R-3fO???  
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return n; ;OqB5qd  
} W-NDBP:  
Ym%xx!9  
wE+${B03  
} .*m>\>Gsgw  
J'$>Gk]  
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/* fU=B4V4@  
**SiteInfoBean.java Mmpfto%i  
*/ _XCOSomL`  
package NetFox; >
pI;%'  
hxQqa 0B  
y@0E[/O  
public class SiteInfoBean { BauU{:Sh  
C8 \5A8c  
M5gWD==uP  
private String sSiteURL; //Site's URL -f*P nxg  
private String sFilePath; //Saved File's Path sMu] /'7  
private String sFileName; //Saved File's Name ]a5 f2lE  
private int nSplitter; //Count of Splited Downloading File '%q$`KDb  
(L^]Lk x)  
% qV 6  
public SiteInfoBean() *G* k6.9W!  
{//nSplitter的缺省值为5 !1e6Ss  
//default value of nSplitter is 5 d3=KTTi\  
this("","","",5); sI{ M  
} phM>.y_  
|*}4 m'c  
15o9 .   
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) L4!{h|  
{ B95B|tU>.  
sSiteURL= sURL; /!c${W!sY  
sFilePath = sPath; ]]zPq<b2  
sFileName = sName; 0#nPbe,Lj  
this.nSplitter = nSpiltter; YW7b)uYf  
>0"+4<72  
^]TVo\,N  
} c%MW\qx  
l1f\=G?tmU  
O)[1x4U  
public String getSSiteURL() vM5k_D  
{ ZIQ [bE7  
return sSiteURL; hEp(A8g)bQ  
} uD^cxD  
yU9DSY\m{  
]*AR,0N&  
public void setSSiteURL(String value) _H5o'>=  
{ HS
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sSiteURL = value; 1fpQLaT  
} 8P|D13- Q  
2AMo:Jqv  
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public String getSFilePath() g*_cPU0~m  
{ VIv&ofyAR  
return sFilePath; 0N$v"uX@  
} 9b9$GyI  
NuQdSj_>  
zzX_q(:S  
public void setSFilePath(String value) HhvdqvIEG  
{ x^y'P<ypw  
sFilePath = value; tNbN7yI  
} !6*"(  
S[J}UpV  
_no*k?o*  
public String getSFileName() ee^{hQi  
{ ?!` /m|"  
return sFileName; 0@%v1Oja  
} *2
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eS~LF.^Jw  
-w"VK|SGm  
public void setSFileName(String value) 5fd]v<  
{ ~5}*
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sFileName = value; 5:KQg  
} 
Zg{KFM%  
ppVHLrUh  
@X#F3;  
public int getNSplitter() }f6HYU  
{ oYH^_V  
return nSplitter; R8a3 1&  
} .nx2";oi  
` 2V19
s]  
oYm[V<nIl  
public void setNSplitter(int nCount) G$F<$  
{ Wa{`VS  
nSplitter = nCount; @eKec1<  
} ddJe=PUb  
} ! t?iXZ  
Ezd_`_@R  
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/* j}.\]$J  
**Utility.java CDK5  
*/ !xo{-@@wS  
package NetFox; /}b03  
rrik,qyv6  
] Zy5%gI  
public class Utility { s;01u_  
{#?N  
>I-RGW'A  
public Utility() *Doa*wQ  
{ LnH?dy  
CYY=R'1:G{  
'!
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} ! |<Fo'U  
kuszb~`zPY  
//线程睡眠 pZqq]mHK  
public static void sleep(int nSecond)  KY$)#i  
{ #P0&ewy  
try{ r\'A i6  
Thread.sleep(nSecond); o$jLzE"  
} uKUiV%p!  
catch(Exception e) g| I6'K!<  
{ O;:mCt _H  
e.printStackTrace (); z[L8
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} !Prg_6 `  
} 0"  
Nfrw0b  
//日志 1WxK#c-)  
public static void log(String sMsg) $P/~rZ@M@  
{ PNgY>=Y  
System.err.println(sMsg); lrlgz[  
} W$hx,VEy`  
&=] ~0$  
Yg%I?  
public static void log(int sMsg) v&DI`xn~  
{  ]hk  
System.err.println(sMsg); )rxX+k+b/  
} I9_RlAd  
} ;g+N&)n  
[+T.at  
saBVgSd  
/* ]%@M>?Ywc  
**TestMethod.java 4i)1'{e  
*/ fg_4zUGM+g  
package NetFox; .,<1%-R34q  
J\twZ>w~0  
6-N?mSQU  
public class TestMethod { N} G[7Rp8l  
vdivq^%=a  
{6|38$Rl  
public TestMethod() Y!-M_v/  
{ ///xx/weblogic60b2_win.exe ype$ c  
try{ `2("gUCm  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); PUT=C1,OFR  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); mqD}BOif  
SiteFileFetch fileFetch = new SiteFileFetch(bean); LM~[@_j  
fileFetch.start(); |W,& Hl7  
} } gyj0  
catch(Exception e){e.printStackTrace ();} z+0I#kM"1  
md)c0Bg8~  
LG{,c.Qj*  
} %9KldcQ}~  
N7b8m?!  
{f3YsM;]C  
public static void main(String[] args) 3%#3iZ=_  
{ nv*FT  
new TestMethod(); 5sj4
;w[  
} 7zXvnxYE  
} kbX8$xTM  
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