http断点续传简单实现（java)

/* .umN>/o[  
**SiteFileFetch.java ge]Z5E(1  
*/ z .+J\  
package NetFox; zHD8\*  
import java.io.*; ETm:KbS  
import java.net.*;  N8)]d  
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public class SiteFileFetch extends Thread { 0v|qP  
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SiteInfoBean siteInfoBean = null; //文件信息Bean w>4( hGO  
long[] nStartPos; //开始位置 ^ f[^.k$3d  
long[] nEndPos; //结束位置 y/>Nx7C0=2  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ~m4LL[  
long nFileLength; //文件长度 *rVI[kL  
boolean bFirst = true; //是否第一次取文件
{S`Rr/E|%  
boolean bStop = false; //停止标志 N}Or+:"O:q  
File tmpFile; //文件下载的临时信息 NNBT.k3)  
DataOutputStream output; //输出到文件的输出流 x@*?~1ai  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） G_}oI|B  
public SiteFileFetch(SiteInfoBean bean) throws IOException 44pVZ5c  
{ AZ SaI  
siteInfoBean = bean; ,xutI  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); L7"<a2J  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); C'PHbo:  
if(tmpFile.exists ()) ab[V->>%  
{ s$~H{za  
bFirst = false; `)NTJc$):  
read_nPos(); 65GC7 >[  
} G+tzp&G@  
else (!a\23  
{ jGYl*EBx  
nStartPos = new long[bean.getNSplitter()]; ^97[(89G9  
nEndPos = new long[bean.getNSplitter()]; Ky*xAx:  
} ,=2)1I]  
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} x[R?hS,0t  
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public void run() 212 =+k  
{ ]UrlFiR  
//获得文件长度 GS*_m4.Ry6  
//分割文件 G+WCE*  
//实例FileSplitterFetch OqX+R4S  
//启动FileSplitterFetch线程 fO837  
//等待子线程返回 Q'[~$~&`  
try{ w$`u_P|@E:  
if(bFirst) I.o3Ol
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{ ltHuN;C\  
nFileLength = getFileSize(); n.A*(@noe  
if(nFileLength == -1) xOZvQ\%  
{ xM>dv5<E  
System.err.println("File Length is not known!"); _he~Y2zFz  
} xEB4oQ5  
else if(nFileLength == -2) ]0pI6"  
{ DvTbt?i[  
System.err.println("File is not access!");  aqwW`
\  
} \rCdsN2H  
else n&8N`!^o  
{ =|d5V%mK  
for(int i=0;i<nStartPos.length;i++) p+2uK|T9  
{ }'\M}YM  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); E8o9ufj3  
} 7KtgR=-Lb  
for(int i=0;i<nEndPos.length-1;i++) 4-\4G"4  
{ +EZr@  
nEndPos = nStartPos[i+1]; >P6U0  
} ! &
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nEndPos[nEndPos.length-1] = nFileLength; VKi3z%kwK  
}  XV!UeBq  
} !)c0  
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//启动子线程 ik0w\*  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 2Mu(GUe;  
for(int i=0;i<nStartPos.length;i++) eoPoG
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{ mW)"~sA  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), QEEX|WM  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 'YEiT#+/  
nStartPos,nEndPos,i); x_EU.924uY  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); &0mhO+g
 
fileSplitterFetch.start(); *gI9CVfQl  
} 6uFGq)4p@  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ND5E`Va5R  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); JM*rPzp  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", *JaFt@ x  
nEndPos = " + nFileLength); =PoPp  
// fileSplitterFetch[nPos.length-1].start(); #elaz8 5  
\)PS&Y8n  
Pv@;)s(-  
//等待子线程结束  *8 ]  
//int count = 0; b;I!CyD  
//是否结束while循环 Bc#6mO-  
boolean breakWhile = false; [92bGR{  
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while(!bStop) BimM)4g  
{ U3w*z6OG  
write_nPos(); r3.v^  
Utility.sleep(500); wD[qE  
breakWhile = true; hpticW|  
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for(int i=0;i<nStartPos.length;i++) &l~=c2  
{ 7M9s}b%?  
if(!fileSplitterFetch.bDownOver) 3*b!]^d:D  
{ &S#bLE  
breakWhile = false; $w<~W1\:  
break; }Z\+Qc<<  
} g/,O51f'  
} J15$P8J  
if(breakWhile) WTh|7&  
break; SiJX5ydz  
q}5&B=2pM  
upH%-)%'  
//count++; /XW,H0pR  
//if(count>4) ;"GI~p2~7  
// siteStop(); 4U:+iumy2  
} Y'%_--  
^F1zkIE  
:Ee5:S   
System.err.println("文件下载结束！"); 9a_(_g>S  
} /t?(IcP5  
catch(Exception e){e.printStackTrace ();} =j~}];I  
} or]s  
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//获得文件长度 |&%l @X6  
public long getFileSize() %u|qAF2uS  
{ ~LzTqMHM  
int nFileLength = -1; k)USLA  
try{ r,dxW5v.  
URL url = new URL(siteInfoBean.getSSiteURL()); 8%#uZG\}  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); BF6H_g  
httpConnection.setRequestProperty("User-Agent","NetFox"); ihhnB  
3'2}F%!Mv  
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int responseCode=httpConnection.getResponseCode(); }c,}+{q
 
if(responseCode>=400) P.1iuZ "w  
{ I!Za2?  
processErrorCode(responseCode); `P4qEsZE>`  
return -2; //-2 represent access is error gf2w@CVF>=  
} _E[{7"3}  
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String sHeader; W.,J'  
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for(int i=1;;i++) `\P:rn95;  
{ Y<.F/iaH  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); D2Go,1  
//Utility.log(in.readLine()); _>:g&pS/  
sHeader=httpConnection.getHeaderFieldKey(i); tdr*>WL  
if(sHeader!=null) vR~*r6hX8  
{ $Y0bjS2J  
if(sHeader.equals("Content-Length")) M+^K,  
{ #(*WxVE  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); /ADxHw`k  
break; x{*!"a>  
} S8vmXlD  
} C127he  
else {nOK*7+"  
break; T[q-$8U  
} r5iO%JFg  
} @#H{nj Z  
catch(IOException e){e.printStackTrace ();} v981nJ>w,  
catch(Exception e){e.printStackTrace ();} 25ZGuM  
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Utility.log(nFileLength); D+o.9I/{  
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return nFileLength; {Rj'=%h  
} X-{:.9  
}\DQxHG  
\ bT]?.si  
//保存下载信息（文件指针位置） n"K7@[d  
private void write_nPos() Z#MODf0H@  
{ 'HcDl@E  
try{ JN KZ'9  
output = new DataOutputStream(new FileOutputStream(tmpFile)); F5<{-{Ky  
output.writeInt(nStartPos.length); u\.sS|
$  
for(int i=0;i<nStartPos.length;i++) f|^f^Hu:{  
{ NxX1_d  
// output.writeLong(nPos); N[+dX_h  
output.writeLong(fileSplitterFetch.nStartPos); Gj_b GqF8}  
output.writeLong(fileSplitterFetch.nEndPos); D
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} MM8)yCI  
output.close(); ,m b3H  
} "^D6%I#T  
catch(IOException e){e.printStackTrace ();} c\b>4 &n  
catch(Exception e){e.printStackTrace ();} !Z'm@,+  
} +li^0+3-'  
GyPN)!X@.&  
:A{-^qd(  
//读取保存的下载信息（文件指针位置） !yI)3;$*  
private void read_nPos() gq@."wHU  
{ N8{>M,  
try{ _5LlL#)  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); F_Pd\Aq8  
int nCount = input.readInt(); X*yl%V  
nStartPos = new long[nCount]; z0W+4meoH  
nEndPos = new long[nCount]; 4 z`5W,  
for(int i=0;i<nStartPos.length;i++) YWZF*,4  
{ hB+ t pa  
nStartPos = input.readLong(); |}|;

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nEndPos = input.readLong(); SA7,]&Zb  
} kv4J@  
input.close(); T?ZMmUE  
} 6e*b;{d  
catch(IOException e){e.printStackTrace ();} <C{5(=
X{  
catch(Exception e){e.printStackTrace ();} _/=ZkI5  
} zXCIn  
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private void processErrorCode(int nErrorCode) sq^"bLw  
{ *sG<w%%  
System.err.println("Error Code : " + nErrorCode); -/qrEKQ0U?  
} KE3v3g<  
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]$  
]/']{*T1  
//停止文件下载 %%>?<4t  
public void siteStop() ZF/KV\Ag)  
{ #"M Pe4  
bStop = true; *j* WE\  
for(int i=0;i<nStartPos.length;i++) j&pgq2Kl  
fileSplitterFetch.splitterStop(); wg1pt1 `  
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} gZUy0`E  
} ;hvXFU  
//负责部分文件的抓取 hF1/=;>  
**FileSplitterFetch.java O?WaMfS[1  
*/ VfwD{+5  
package NetFox; V"ZbKV+[  
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!%X`c94  
import java.io.*; D+3Y.r9  
import java.net.*; z Y|g#V-  
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public class FileSplitterFetch extends Thread { l}2WW1b(  
;^*!<F%t9R  
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String sURL; //File URL iPOZ{'Z  
long nStartPos; //File Snippet Start Position <.B s`P  
long nEndPos; //File Snippet End Position d
L` +^E>  
int nThreadID; //Thread's ID 9F](%/  
boolean bDownOver = false; //Downing is over h;KK6*Z*$E  
boolean bStop = false; //Stop identical S\ZAcz4  
FileAccessI fileAccessI = null; //File Access interface z{d5Lrk  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException J

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{ @;}H<&"  
this.sURL = sURL; sJ/e=1*  
this.nStartPos = nStart; g8"7wf`0k  
this.nEndPos = nEnd; h12wk2@P/]  
nThreadID = id; \xxVDr.  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 i 8X
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} '[
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public void run() 7nz
+
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{ syf"{bBe  
while(nStartPos < nEndPos && !bStop) => =x0gsgj  
{ ,`zRlkX  
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try{ \2xBOe-a]  
URL url = new URL(sURL); J\'5CG  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ~,68S^nP)H  
httpConnection.setRequestProperty("User-Agent","NetFox"); C
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String sProperty = "bytes="+nStartPos+"-"; ~bTae =FP  
httpConnection.setRequestProperty("RANGE",sProperty); ;x^,t@ xge  
Utility.log(sProperty); _%vqBr*  
+[/r^C  
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InputStream input = httpConnection.getInputStream(); eF^"{a3b  
//logResponseHead(httpConnection); b,R'T+4[  
5]l7Z35  
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byte[] b = new byte[1024]; @a\SR'8  
int nRead; BpG'e-2  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) FT>~ES]cQd  
{ TrU@mYnE  
nStartPos += fileAccessI.write(b,0,nRead); je4&'vyU  
//if(nThreadID == 1) D!a5#+\C  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); A9Wqz"[  
} vfUfrk@D~  
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Utility.log("Thread " + nThreadID + " is over!"); :V~*vLvR  
bDownOver = true; 6.s?  
//nPos = fileAccessI.write (b,0,nRead); wrYQ=u#Z  
} rDX'oP:  
catch(Exception e){e.printStackTrace ();} {IHK<aW  
} o`mIi  
} hO.G'q$V  
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8]":[s6x  
//打印回应的头信息 <>i+R#u{  
public void logResponseHead(HttpURLConnection con) n qLAby_  
{ -5v.1y=!L  
for(int i=1;;i++) mv*T=N8fC  
{ kj!7|1i2  
String header=con.getHeaderFieldKey(i); Au} ;z6k  
if(header!=null) vj&5`  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 4t Nvq  
Utility.log(header+" : "+con.getHeaderField(header)); h+~df(S.  
else \41)0,sEy  
break; <yI,cM<c  
} !LIfeL.4h  
}
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- (_e=3$  
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public void splitterStop() )YMlFzYr  
{ NJ)2+  
bStop = true; 3
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} Dbdzb m7  
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} @" 0tW:  
:~3{oZGX&  
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/* )d(0Y<e@  
**FileAccess.java XyM(@6,'  
*//文件访问(定位，写) d&T6p&V$  
package NetFox; =Xy`"i{`(  
import java.io.*; s"',370  
`}~)1'(#/  
\q|7,S,5  
public class FileAccessI implements Serializable{ (#B^Hyz!  
6{+_T  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 }u-S j/K  
RandomAccessFile oSavedFile; lIVxW+  
long nPos; w"a 9'r  
L;S*.Ol>  
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public FileAccessI() throws IOException HKiVEg  
{ H*{k4  
this("",0); r=DHt&x=  
} Ue3B+k9w  
}kCn@  
P,/13tZ#3  
public FileAccessI(String sName,long nPos) throws IOException } }f_  
{ m c\
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oSavedFile = new RandomAccessFile(sName,"rw"); 2#b<d?"  
this.nPos = nPos; dT]L-uRZgy  
oSavedFile.seek(nPos); !jAWNK6  
} jj3Pf>D+k  
Vo9>o@FlLM  
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public synchronized int write(byte[] b,int nStart,int nLen) D#d8^U  
{ tCbr<Ug  
int n = -1; 0ck&kpL:9  
try{ eMN+qkvH  
oSavedFile.write(b,nStart,nLen); Wg`+u  
n = nLen; L7Qo-  
} ]D{c4)\7C|  
catch(IOException e) pfL2v,]g  
{ r}R^<y@I  
e.printStackTrace (); dqD;y#/  
} 8K.s@<  
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i'!jx.  
return n; cB
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} 8lOZIbwS  
..jq[(;N  
8B*E+f0  
} x/%7%_+'  
#.)xm(Ys  
]{|fYt_-  
/* "u<jbD  
**SiteInfoBean.java /[Bl  
*/ }%!FMXe  
package NetFox; V;iL[  
JlC<MQ?  
J[}gku?C;  
public class SiteInfoBean { M)"]$TM  
!K3i-zY  
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private String sSiteURL; //Site's URL 
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private String sFilePath; //Saved File's Path #)_J)/h  
private String sFileName; //Saved File's Name _8[UtZYG  
private int nSplitter; //Count of Splited Downloading File y _'eyR@)  
C~ZE95g  
X2\E9hJg  
public SiteInfoBean() X)Dqeb6  
{//nSplitter的缺省值为5 UsLh)#}h  
//default value of nSplitter is 5 9m\)\/V  
this("","","",5); S9G8aea/  
} BgJkrv7~  
%"l81z  
[as-3&5S  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) oMh~5 W  
{ 0\5M^:8i3  
sSiteURL= sURL; u?q&K|  
sFilePath = sPath; Zk]k1]u*5  
sFileName = sName; xw4ey<"I  
this.nSplitter = nSpiltter; 09R,'QJ|  
7<EJo$-j  
<ZigCo w  
} M[h1>}$Lz  
,^.S0;D,Z  
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public String getSSiteURL() 5R,la\!bQ  
{ $42Au2Jg  
return sSiteURL; E7rX1YdR  
} o-SRSu  
C!!mOAhJ
 
T(Y}V[0+  
public void setSSiteURL(String value) [urH a  
{ )UR1E?'  
sSiteURL = value; J#6LSD@(O  
} [zY!'cz?  
QjQ4Z'.r>  
|yLk5e~@-  
public String getSFilePath() i[^k.W3gf  
{ 1KW3l<v-6  
return sFilePath; 3hc#FmLr2b  
} `6rrXU6|  
.r~'(g{qt  
McEmd.S<n  
public void setSFilePath(String value) }l.KpdRT2  
{ LkaG8#m1R  
sFilePath = value; M$,Jg5Dc  
} )*!1bgXQ  
NmjzDN  
;xSRwSNDi(  
public String getSFileName() >4Iv[ D1  
{ j: <t  
return sFileName; q^u1z|'Z  
} Lb!r(o>8Cb  
dO+kPC  
7k3p'FeS  
public void setSFileName(String value) HKpD2M  
{ PdR >;$1  
sFileName = value; Qqp)@uM^  
} PT mf  
6yN" l Q7  
--Oprl  
public int getNSplitter() c+1vqbqHG  
{ =Q@6c   
return nSplitter; PM@XtL7J  
} j\
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f](I.lm:  
Z%Vr+)!4  
public void setNSplitter(int nCount) ?hKm&B;d  
{ 6%>/og\%  
nSplitter = nCount; {n\6BT
s  
} !2(.$}E  
} Cq gJ  
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]+
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/* Y]~IY?I  
**Utility.java Bk+{}  
*/
H]BAW*}  
package NetFox; SAP;9*f1\  
8AryIgy>@  
#`vVgGZ&  
public class Utility { 658\#x8|  
ja?s@Y}-9s  
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public Utility() .
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{ EVG"._I@  
Axf^
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} (JWv *p  
Q2q|*EL  
//线程睡眠 Eevw*;$x  
public static void sleep(int nSecond) N50fL  
{ E$w#+.QP  
try{ z=B< `}@3  
Thread.sleep(nSecond); 3i6h"Wu`n  
} \OP9_J(*  
catch(Exception e)
_y>}#6B  
{ M=W 4:H,gx  
e.printStackTrace (); YtMlqF  
} ]s_@n!  
} au}s=ua~i  
"tKNlHBu'  
//日志 t|.Ft<c#  
public static void log(String sMsg) .W$ sxVXB  
{ xLZbU4  
System.err.println(sMsg); ZlrhC= 0  
} s*f1x N<  
I :@|^PYw  
ly[lrD0Kn.  
public static void log(int sMsg) a/b92*&k  
{ k
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System.err.println(sMsg); 5\&]J7(  
} Uh}+"h5  
} nW11wtiO.  
g**5z'7  
^Wm*-4  
/* vnL?O8`c  
**TestMethod.java JxHv<p[  
*/ ).Q[!lly  
package NetFox; T
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[T-*/}4$  
?]5Ix1  
public class TestMethod { (V!0'9c  
J B(<.E2  
5~QTg  
public TestMethod() 1)'Iu`k/  
{ ///xx/weblogic60b2_win.exe [EER4@_  
try{ <W2ZoqaV  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); {<!hlB  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); %P;[fJ `G  
SiteFileFetch fileFetch = new SiteFileFetch(bean); QAi1,+y]7w  
fileFetch.start(); u3ST;  
} L@?e:*h  
catch(Exception e){e.printStackTrace ();} a5)JkC  
1U'ZVJ5bpK  
fq=:h\\G  
} AC'lS >7s  
>P<'L4;  
zC#%6@P\  
public static void main(String[] args) 2 ZK%)vq0  
{ 1LX)4TCC  
new TestMethod(); ~XKZXGw  
} EWO /u.z  
} @%:E }  
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