http断点续传简单实现（java)

/* XsJ`x  
**SiteFileFetch.java /Z*$k{qIR&  
*/ 5K9W5hA:D  
package NetFox; (9( xJ)  
import java.io.*; %P1zb7:8  
import java.net.*; f5bX,e)!  
QE"$Lc)  
:|k!hG  
public class SiteFileFetch extends Thread { +7OE,RoQ  
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4J,6cOuW4  
SiteInfoBean siteInfoBean = null; //文件信息Bean Mfz(%F|<  
long[] nStartPos; //开始位置 o/
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long[] nEndPos; //结束位置 b?0WA.[{  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 J6EzD\.Y)  
long nFileLength; //文件长度 hU(  
boolean bFirst = true; //是否第一次取文件 &/uakkS  
boolean bStop = false; //停止标志 \4$Nx/@Q}  
File tmpFile; //文件下载的临时信息 l]DRJ  
DataOutputStream output; //输出到文件的输出流 Bz,D4E$  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） R-n%3oh  
public SiteFileFetch(SiteInfoBean bean) throws IOException b*|?7  
{ |1ry*~  
siteInfoBean = bean; (*eX'^Q)d  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); rA<J^dX=C  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); :FSg%IUX  
if(tmpFile.exists ()) :W&klUU"  
{ GPAC0K^p  
bFirst = false; vr47PM2al  
read_nPos(); (.oDxs()I  
} FLPN#1  
else Th,]nVsGs~  
{ E.$//P n|1  
nStartPos = new long[bean.getNSplitter()]; @:hWahMy  
nEndPos = new long[bean.getNSplitter()]; W{ozZuo  
} AS0(NlV  
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} <5]_u:  
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public void run() /Y\q&}  
{
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//获得文件长度 7je1vNs  
//分割文件 T;3~teVYB  
//实例FileSplitterFetch )`5-rm~*  
//启动FileSplitterFetch线程 D//58z&  
//等待子线程返回 O{]}{Ss  
try{ 4byh,t  
if(bFirst) w\t  
{ .*FlB>1jy  
nFileLength = getFileSize(); /%?bO-  
if(nFileLength == -1) >)+U^V  
{ uTbMp~cYB  
System.err.println("File Length is not known!"); (o6u^#6  
} W#b++}S  
else if(nFileLength == -2) mMhe,8E&  
{ _;(QMeR  
System.err.println("File is not access!"); 3joMtRB>;  
} a3Z()|t>  
else _["97>q  
{ Vyx&MU.-J  
for(int i=0;i<nStartPos.length;i++) jq/{

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{ &xlOsr/n  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); f}FJR6VO  
} EjVB\6,  
for(int i=0;i<nEndPos.length-1;i++) y;9K
 
{ NVC$8imip  
nEndPos = nStartPos[i+1]; )[sSCt]  
} #@5 jOi  
nEndPos[nEndPos.length-1] = nFileLength; CA"`7<,  
} n |,}   
} 4P24ySy9F  
B;{sr'CP  
9qZ|=r]y'  
//启动子线程 SLd9-N}T  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; MT&q~jx*  
for(int i=0;i<nStartPos.length;i++) \v9<L'NP)  
{ e8]mdU{)  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), H~*[v"  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), &P8Q|A-u  
nStartPos,nEndPos,i); x2f_>tu2  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ?~VevD  
fileSplitterFetch.start(); UgO\+cI  
} >yq
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// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), oWOH#w  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); z#&qWO  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", \}qv}hU  
nEndPos = " + nFileLength); ]@1ncn7N  
// fileSplitterFetch[nPos.length-1].start(); RzSN,bLR  
p7O4CP>9[  
p/s5[>N  
//等待子线程结束 CV7.hF<  
//int count = 0; z!j`Qoh?V9  
//是否结束while循环 WHF:>0B  
boolean breakWhile = false; 2
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]gj@r[  
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while(!bStop) 8%U)EU  
{ t,P+~ A  
write_nPos(); Wq
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Utility.sleep(500); 5O%}.}n  
breakWhile = true; 2Z..~1r  
IPE
(  
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for(int i=0;i<nStartPos.length;i++) a. 5`Q2  
{ ~JT{!wcE}o  
if(!fileSplitterFetch.bDownOver) e
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{ [K9q+  
breakWhile = false; I3aEg  
break; +~/zCJ;F  
} \J\1i=a-=  
} CblL1q8  
if(breakWhile) f%auz4CZz  
break; /3Gv51'  
Qg oXOVo6  
eaiz w@N  
//count++; ~d5{Q?T)  
//if(count>4) sQH.}W$C  
// siteStop(); x[oYN9O  
} >"nk}@  
j+ys&pDczm  
Pr/&p0@aV  
System.err.println("文件下载结束！"); CC87<>V  
} nocH~bAf2  
catch(Exception e){e.printStackTrace ();} !kKKJ~,;  
} \1B*iW  
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//获得文件长度 :3Jh f$  
public long getFileSize() I5"=b}V5  
{ u})JQ<|  
int nFileLength = -1; \)"qN^we  
try{ ?%0i,p@<  
URL url = new URL(siteInfoBean.getSSiteURL()); QY fS-  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); !c`1~a!  
httpConnection.setRequestProperty("User-Agent","NetFox"); jKQP0 t-  
:{6[U=O  
5Q'R5
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int responseCode=httpConnection.getResponseCode(); =UP)b9*h  
if(responseCode>=400) 4* hmeS"  
{ _1JvA-  
processErrorCode(responseCode); hg>YOf&RG  
return -2; //-2 represent access is error ! O>mu6:Rf  
} Yr,1##u  
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+%~g$#tlJo  
String sHeader; t-Fl"@s
 
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for(int i=1;;i++) zj)[Sntn?  
{ DpR%s",Q  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); i!nl%%  
//Utility.log(in.readLine()); %?$"oWmenS  
sHeader=httpConnection.getHeaderFieldKey(i); JZ7-? o  
if(sHeader!=null) %qv7;E2C  
{ /][U$Q;Ke  
if(sHeader.equals("Content-Length")) D.GSl  
{ jHZ<Gc  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 3WVHI$A9  
break; zBR]bk\  
} +Snjb0  
} J{ Vl2P?@  
else 3IxT2@H)  
break; U#P#YpD;==  
} RinRQd  
} Tk:y>P!%a  
catch(IOException e){e.printStackTrace ();} N@>S>U8C  
catch(Exception e){e.printStackTrace ();} >JMKEHl.q  
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Utility.log(nFileLength); ( FRf.mv{  
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return nFileLength; |+bG~~~%j  
} hdB[H8Q  
#@fypCc  
UTt#ltun?  
//保存下载信息（文件指针位置） jj2UUQ|  
private void write_nPos() T_-MSXhA  
{ ^J_hkw~gO  
try{ qr9F  
output = new DataOutputStream(new FileOutputStream(tmpFile)); >>r:L3<!  
output.writeInt(nStartPos.length); -G 'lyH  
for(int i=0;i<nStartPos.length;i++) mI%/k7:sf  
{ $\ '\@3o  
// output.writeLong(nPos); _u>>+6,p  
output.writeLong(fileSplitterFetch.nStartPos); qg/5m;U  
output.writeLong(fileSplitterFetch.nEndPos); h(-&.Sm")H  
} A@OV!DJe]  
output.close(); Q:
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} O)R0,OPb
  
catch(IOException e){e.printStackTrace ();} @El<"\  
catch(Exception e){e.printStackTrace ();} xJ
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} Kc0OLcu^d  
}TW=eu~  
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//读取保存的下载信息（文件指针位置） @
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private void read_nPos() `%3p.~>  
{ mtHz6+  
try{ .)w0C%]  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); l0{DnQA>I  
int nCount = input.readInt();
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nStartPos = new long[nCount]; ]w>fnew  
nEndPos = new long[nCount]; !%r`'|9y  
for(int i=0;i<nStartPos.length;i++) (xed(uFEK  
{ S+Yg!RrNqj  
nStartPos = input.readLong(); =1\wZuK#  
nEndPos = input.readLong(); [!mjUsut*  
} Rn_c9p  
input.close(); CaBS0' n  
} FOi`TZ8  
catch(IOException e){e.printStackTrace ();} ':]a.yA\1  
catch(Exception e){e.printStackTrace ();} w.p'Dpw  
} C:MGi7f  
]H~,K]@.  
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private void processErrorCode(int nErrorCode) 'Y\"^'OU\  
{ 0\@|M@X=  
System.err.println("Error Code : " + nErrorCode); GuvF    
} yW?%c#9D  
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//停止文件下载 LW5ggU/  
public void siteStop() '/g+;^_cB  
{ Cpv%s 1M  
bStop = true; e~]e9-L>I  
for(int i=0;i<nStartPos.length;i++) }#5roNH~Z  
fileSplitterFetch.splitterStop(); .WyX/E$I^!  
iGVb.=)  
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} 3MJWCo-[  
} }A/&]1GWk  
//负责部分文件的抓取 <|Eby!KXR  
**FileSplitterFetch.java eAKQR  
*/ 14!a)Ijl  
package NetFox; M;V#Gm  
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4~YQ\4h=  
import java.io.*; C+m^Z[
 
import java.net.*; E/$@ud|l"  
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public class FileSplitterFetch extends Thread { Z)T@`B6  
,h.Jfo54,  
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String sURL; //File URL 0*/ r'  
long nStartPos; //File Snippet Start Position c&?a,fpb  
long nEndPos; //File Snippet End Position <;0N@  
int nThreadID; //Thread's ID ';|>`<  
boolean bDownOver = false; //Downing is over Hs-.83V  
boolean bStop = false; //Stop identical )k] !
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FileAccessI fileAccessI = null; //File Access interface V3~a!k  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException hIo S#]  
{ wp*&&0O!  
this.sURL = sURL; 9iddanQA  
this.nStartPos = nStart; +\[![r^P  
this.nEndPos = nEnd; `e'o~oSu  
nThreadID = id; .O%1)p  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 CSqb)\8Oi*  
} q '{<c3&  
/0&:Yp=>  
 )P9{47  
public void run() {G1aAM\Hz  
{ 4[CBW  
while(nStartPos < nEndPos && !bStop) \g:qQ*.  
{ '[yqi1 &  
|U$de2LF  
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try{ HZ<f(  
URL url = new URL(sURL);
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); g6/N\[b%  
httpConnection.setRequestProperty("User-Agent","NetFox"); vWi.[]  
String sProperty = "bytes="+nStartPos+"-"; Z0 IxYEp  
httpConnection.setRequestProperty("RANGE",sProperty); 8xpYQ<cax  
Utility.log(sProperty); NRuG?^/}d  
#[0\=B-  
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InputStream input = httpConnection.getInputStream(); )C01fZ
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//logResponseHead(httpConnection); L8w76|  
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byte[] b = new byte[1024]; ,dj*p,J  
int nRead; CVSsB:H6e  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) s@)"IdSA(  
{ EfBVu  
nStartPos += fileAccessI.write(b,0,nRead); !k= 0X\5L  
//if(nThreadID == 1) azDC'.3{p  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ^Im%D(MY  
} uJ/?+5TU  
9<(K6Q  
8K JQ(  
Utility.log("Thread " + nThreadID + " is over!"); Z(k\J|&9C  
bDownOver = true; jle%|8m&@  
//nPos = fileAccessI.write (b,0,nRead); jPYe_y  
} O*J_+6  
catch(Exception e){e.printStackTrace ();} |h=+&*(:  
} hr!f:D  
} n@07$lY@;  
Ij6Wz.*  
[ 4Y `O  
//打印回应的头信息 Msa6yD#  
public void logResponseHead(HttpURLConnection con) 0nD=|W\@{  
{ VM]GYz|#]  
for(int i=1;;i++) `l gjw=  
{ _+Jf.n20  
String header=con.getHeaderFieldKey(i); |1QbO`f/F  
if(header!=null) ]zvVY:v  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); +>!B(j\gx  
Utility.log(header+" : "+con.getHeaderField(header)); 5e/qgI)M5  
else l@tyg7CwY  
break;
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} aO^:dl5  
} wSJ]3gJM`  
%7(kP}y*  
>NH4A_  
public void splitterStop() Vh#Mp!  
{ )pZekh]v  
bStop = true; r}y[r}vk  
} V@f6Lj  
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.W@(nQ-<  
} s?@)a,C%k  
<nb3~z1  
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/* DD@)z0W  
**FileAccess.java `j}_BW_  
*//文件访问(定位，写) _Vo)<--+I  
package NetFox; 'Wf?elB+  
import java.io.*; 1A?\BJ"  
5U)ab3:  
FM9X}%5nu9  
public class FileAccessI implements Serializable{ Q_QKm0!  
iBKb/Oi6  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 0E?s>-b  
RandomAccessFile oSavedFile; 62MRI  
long nPos; @QVqpE<|  
&
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public FileAccessI() throws IOException .B 85!lCF  
{ P>{US1t  
this("",0); 42V,PH6o  
} X/E7o92\  
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%qS]NC  
public FileAccessI(String sName,long nPos) throws IOException bSrRsgKvT  
{ B=Zl&1  
oSavedFile = new RandomAccessFile(sName,"rw"); + %MO7vL  
this.nPos = nPos; (Pk"NEP  
oSavedFile.seek(nPos); aJ5H3X}Y  
} c7+Djqs  
aE7u5PM  
%ezb^O_6v  
public synchronized int write(byte[] b,int nStart,int nLen) ggm2%|?X  
{ *3_f&Y  
int n = -1; ySwYV  
try{ Cdp]Nv6  
oSavedFile.write(b,nStart,nLen); 4?>18%7&  
n = nLen; I!$jYY2  
} Ic[}V0dk  
catch(IOException e) 49+ >f
 
{ p{ @CoOn  
e.printStackTrace (); mVv\bl?<  
} J+)'-OFt0  
MvFM,  
J$#h(D%  
return n; &jV9*  
} ?~"`^|d  
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} *M> iZO*@  
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/* 0PnD|]9:  
**SiteInfoBean.java $nB-ADRu@  
*/ 3[0w+{(Q  
package NetFox; 24T@N~\g  
$?FS00p*|X  
7$!`p,@we/  
public class SiteInfoBean { AIZW@Nq.5  
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 20I4r  
private String sSiteURL; //Site's URL Xh.+pJl,*  
private String sFilePath; //Saved File's Path Q7,EY /  
private String sFileName; //Saved File's Name uP{;*E3?  
private int nSplitter; //Count of Splited Downloading File 8{R_6BS  
! jbEm8bt  
_Kc1  
public SiteInfoBean() Dh2:2Rz=#7  
{//nSplitter的缺省值为5 cPpu  
//default value of nSplitter is 5 5cD XWF  
this("","","",5); h [nH<m  
} n?'d|h  
1<xcMn0et  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) )46 0Ed  
{ rkxW UDl   
sSiteURL= sURL; =2^Vgc  
sFilePath = sPath; }qc#lz  
sFileName = sName; BG'6;64kx6  
this.nSplitter = nSpiltter; dCB&c^  
oi7 3YOB  
K!3{M!B  
} \,>_c  
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w[ Axs8N'  
public String getSSiteURL() ,LhEshf  
{ -#hK|1]  
return sSiteURL; o_iEkn  
} pG/ NuImA  
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WK pUn8&N  
public void setSSiteURL(String value) /&CUspb  
{ CV'&4oq  
sSiteURL = value; }l~]b3@qu  
} %$Aqbd  
t,RyeS/  
sz'p3  
public String getSFilePath() |<sf:#YzY&  
{ cp$.,V  
return sFilePath; :@.C4oq  
} :~yzDk\I"-  
CE)*qFs  
:`D'jF^S  
public void setSFilePath(String value) QQ@9_[N  
{ /:U1!9.y  
sFilePath = value; 
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} YU&4yk lE  
f2NA=%\  
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public String getSFileName() Hw Z^D=A  
{ 0z/h
+,  
return sFileName; g;8M<`qvf  
} 1Yud~[c  
cn$5:%IK  
ji}#MBac  
public void setSFileName(String value) ASR-a't6  
{ `%|u!  
sFileName = value; *xPB<v2N:P  
} ugno]5Ni  
Qh^R Ax  
/mc*Hc8R8  
public int getNSplitter() @8|Gh]\P  
{ D-6
  
return nSplitter; ,s0 9B  
} @d&g/ccMxd  
'GkvUrD9D$  
B22b&0  
public void setNSplitter(int nCount) [a@B =E  
{ ' PELf P8  
nSplitter = nCount; >)LAjwhBp  
} 
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} d<#p %$A4  
|"Z-7@/k$i  
D ZVXz|g  
/* 3)Zu[c[%'J  
**Utility.java Vb2\/e:k  
*/ ZW>o5x__b  
package NetFox; 6J\q`q(W(  
|~eY%LB  
L;3aZt,#O  
public class Utility { y`rL=N#  
$.a|ae|
K  
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public Utility() mbyih+amCr  
{ ;Z*'
D}  
k52QaMKa~A  
&3I$8v|!?  
} c}%es=@  
fWj@e"G  
//线程睡眠 I0iY+@^5  
public static void sleep(int nSecond) 7%4.b7Q  
{ yw'ezpO"  
try{ JA<~xo[Q9  
Thread.sleep(nSecond); gKWzFnW  
} uN9e:;  
catch(Exception e) ailG./I+  
{ +#~O'r]%GG  
e.printStackTrace (); dMJ!>l>2  
} 2SciB*5  
} 
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~T02._E  
//日志 +`| mJa  
public static void log(String sMsg) <7^Kt7k  
{ 3p_b8K_bG  
System.err.println(sMsg); @bT3'K-4  
} ")ED)&e  
9`BEi(z  
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public static void log(int sMsg) zw]3Vg{T  
{ q!&B6]  
System.err.println(sMsg); .b,~f  
} jn$j^51`C  
} wWTQ6~Y%d  
'0RRFO  
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/* B'p5M.6d#:  
**TestMethod.java b66R}=P l  
*/ [/OQyb4F<  
package NetFox; MtUY?O.P2  
n+?-�  
:
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public class TestMethod { Hd0Xx}3&  
C`0%C7  
|{f~Ks%  
public TestMethod() VjB*{,  
{ ///xx/weblogic60b2_win.exe kwlC[G$j7  
try{ #V[SQ=>x[  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); C2G
|?=  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 5
9i]  
SiteFileFetch fileFetch = new SiteFileFetch(bean); PBrnzkoY  
fileFetch.start(); %K zbO0  
} :!O><eQw  
catch(Exception e){e.printStackTrace ();} pds*2p)2  
:tLbFW[  
[D[D`gpjA  
} t8vc@of$c,  
;&kn"b}G;  
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public static void main(String[] args) ;Iq5|rzDn  
{ K_#UZA< Y  
new TestMethod(); uNbIX:L,  
} hk} t:<  
} h$Tr sO  
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