http断点续传简单实现（java)

/* d`?EEO  
**SiteFileFetch.java Ak`?,*LM  
*/ \8{Tj54NA  
package NetFox; 2l+'p[b0>  
import java.io.*; 02^\np  
import java.net.*; K;`*n7=IA  
1-4[w *u>  
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public class SiteFileFetch extends Thread { JqN$B\J,  
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e \kR/<L
 
SiteInfoBean siteInfoBean = null; //文件信息Bean ](ztb)  
long[] nStartPos; //开始位置 6QPbmO]z  
long[] nEndPos; //结束位置 w3>G3=b  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Vhm^<I-d  
long nFileLength; //文件长度 sdewz(xskj  
boolean bFirst = true; //是否第一次取文件 %74f6\  
boolean bStop = false; //停止标志 N'5DB[:c:  
File tmpFile; //文件下载的临时信息 s.Mrd~(Drz  
DataOutputStream output; //输出到文件的输出流 03 v\v9<T  
"tK3h3/Xv  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） La^Zr,T!  
public SiteFileFetch(SiteInfoBean bean) throws IOException f|!@H><  
{ (hY^E(D  
siteInfoBean = bean; Jju?v2y`  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); SN QLEe  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); l29AC}^  
if(tmpFile.exists ()) ]?jmRk^.  
{ Oh}@c~7;  
bFirst = false; T(qHi?Y  
read_nPos(); t!ZFpMv]n  
} q<fj1t1w  
else p7*7V.>X  
{ Z%-uyT@a  
nStartPos = new long[bean.getNSplitter()]; 6|Rj YX  
nEndPos = new long[bean.getNSplitter()]; brn>FFAwO  
} @:9mTP7  
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} b\t@vMJ  
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public void run() l4^8$@;s  
{ 6& 9q6IIy  
//获得文件长度 ?N%5c%oF  
//分割文件 /hyCR___  
//实例FileSplitterFetch Ga*  
//启动FileSplitterFetch线程 aUBu"P$J  
//等待子线程返回 `\-MpNw  
try{ twTRw:.!f  
if(bFirst) cja-MljD  
{ lo>:S1  
nFileLength = getFileSize(); r2Q) Q  
if(nFileLength == -1) Lhgs|*M  
{ g{7?#.7  
System.err.println("File Length is not known!"); & *&  
} 'Cywn^Ym#  
else if(nFileLength == -2) TF,a`?c`  
{ JnH5v(/  
System.err.println("File is not access!"); l)0yv2[h  
} Y9(BxDP_+Y  
else ewinG-hX_  
{ 'VY\ut  
for(int i=0;i<nStartPos.length;i++) 
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{ |1 LKdP  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); L\kT9wWK|  
} D_cd l^  
for(int i=0;i<nEndPos.length-1;i++) R2[ }  
{ ~/R}K g(  
nEndPos = nStartPos[i+1]; nx4E}8!Lh  
} t== a(e  
nEndPos[nEndPos.length-1] = nFileLength; [WunA,IuR  
} <=~'Pd-f(  
} 5z:/d`P[  
&sPu3.p  
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//启动子线程 YWa9|&m1  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; i0&]Ig|;  
for(int i=0;i<nStartPos.length;i++) $2*&\/;-E!  
{ 3nkO+qQ  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 'P)[=+O?t  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), CQ%yki  
nStartPos,nEndPos,i); >qIZ  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); KT
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fileSplitterFetch.start(); a<V* )  
} V-9z{  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), qS2]|7q?Tc  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); xZ&S7G1  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", qT_E=)
1  
nEndPos = " + nFileLength); ?B,B<@='%  
// fileSplitterFetch[nPos.length-1].start(); s}Sxl0  
x1*@PiO,.  
@sb00ad2q  
//等待子线程结束 <b;Oap3  
//int count = 0; vro5G')  
//是否结束while循环 D D Crvl  
boolean breakWhile = false; 8uhB&qxB  
WN?meZ/N/  
_b 8XF&O  
while(!bStop) Hz<)a(r!J  
{ FUTDR-q O  
write_nPos(); i0~L[v9l<  
Utility.sleep(500); g7W\ &  
breakWhile = true; I*)eP||  
(vf5qF^  
1]XIF?_Dm  
for(int i=0;i<nStartPos.length;i++) c'6$`nC  
{ F1o"H/:n  
if(!fileSplitterFetch.bDownOver) NBZ>xp[U  
{ jk}m  
breakWhile = false; }tZA7),L  
break; 3#T_(
  
} RJI*ZNbA  
} OKq={l  
if(breakWhile) Y_Lsmq2!  
break; gb0ZGnI  
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x  
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//count++; '}wYSG-  
//if(count>4) ?`O Dt]s  
// siteStop(); YPq`su7m9  
} EMejvPnZO  
$$G^#t1=XZ  
P X<,/6gz  
System.err.println("文件下载结束！"); Mky8qVQ2  
} yo0?QRT  
catch(Exception e){e.printStackTrace ();} _j2h3lCT  
} $pGk%8l%  
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{*CLWs4  
//获得文件长度 -0doL^A  
public long getFileSize() .el_pg  
{ KPA5 X]  
int nFileLength = -1; MXhRnVz"W  
try{ 57b;{kl  
URL url = new URL(siteInfoBean.getSSiteURL()); VI`x fmVOQ  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); xX.Ox  
httpConnection.setRequestProperty("User-Agent","NetFox"); >KXT2+w  
v)2@;Q  
|KC
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int responseCode=httpConnection.getResponseCode(); Kn9,N@bU_  
if(responseCode>=400) CQ3{'"b  
{ )FqE8oN-  
processErrorCode(responseCode); -Q8pWtt  
return -2; //-2 represent access is error ptuW}"F  
} ~qT+sc!t
  
 '[#uf/~W  
~1h-LbFI2  
String sHeader; =kLg)a |  
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&WHEP
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for(int i=1;;i++) 0\U28zbMJw  
{ M$gy J!Pb  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); f i!wrvO  
//Utility.log(in.readLine()); 9aC>gye!  
sHeader=httpConnection.getHeaderFieldKey(i); HF\L`dJX?  
if(sHeader!=null) \ca4X{x  
{ E%-&!%_>D@  
if(sHeader.equals("Content-Length")) i9)y|  
{ <s#}`R.#2  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ;@d<*  
break; q+o(`N'~G  
} MU&5&)m  
} "v3u$-xN1  
else +o/;bm*U<K  
break; O'-lBf+<  
} Aq|LeH  
} <STjB,_s  
catch(IOException e){e.printStackTrace ();} CsR~qQ 5  
catch(Exception e){e.printStackTrace ();} XW Y0WDh:  
^J~}KOH  
.[Sv|;x"E  
Utility.log(nFileLength); *<#&ne8  
a}c(#ZLs  
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return nFileLength; r%'2a+}D  
} &:jE+l  
nw5#/5xw  
t7A.b~#  
//保存下载信息（文件指针位置） I"JT3[*s  
private void write_nPos() :WCUHQ+  
{ w-CuO4P  
try{ y_QxJ~6t  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 1=(i{D~  
output.writeInt(nStartPos.length); |$b4{
 
for(int i=0;i<nStartPos.length;i++) C.(ZXU7  
{ `?6m0|\@  
// output.writeLong(nPos); 9Jk(ID'c  
output.writeLong(fileSplitterFetch.nStartPos); v @N8v  
output.writeLong(fileSplitterFetch.nEndPos); "3j0)  
} G:e}>'  
output.close(); 3^su%z_%  
} IB*%PMTF  
catch(IOException e){e.printStackTrace ();} U0N[~yW(t1  
catch(Exception e){e.printStackTrace ();} 3.d=1|E  
} d=4MqX r  
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cW GU?cv}  
//读取保存的下载信息（文件指针位置） j^!J:Bj  
private void read_nPos() _Wb-&6{  
{ v*BA\&  
try{ P7y[9|^  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); %""Cac
X  
int nCount = input.readInt(); 0`ib_&yI  
nStartPos = new long[nCount]; X}usyO'pW  
nEndPos = new long[nCount]; WAdl@){  
for(int i=0;i<nStartPos.length;i++) FUcs=7c  
{ {G{@bUG]p  
nStartPos = input.readLong(); @i)tQd!s  
nEndPos = input.readLong(); cq9Q7<&MF  
} 1k/l7&n"  
input.close(); wA~Nfn ^  
} w\2[dd  
catch(IOException e){e.printStackTrace ();} r2H'r ,N  
catch(Exception e){e.printStackTrace ();} >I
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} <0LB]zDWe6  
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private void processErrorCode(int nErrorCode) 462ae` 6l  
{ Z.mV fy%  
System.err.println("Error Code : " + nErrorCode); <m6I)}K  
} ckP3[@Su {  
ca-n:1  
1)PR]s:-m@  
//停止文件下载 ntkinbbD  
public void siteStop() bA^a@ lv a  
{ z vYDE]  
bStop = true; 7kwG_0QO  
for(int i=0;i<nStartPos.length;i++) p.}[!!m P  
fileSplitterFetch.splitterStop(); p4AXQuOP  
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} D&^:hs@  
} {Jy%h8n*  
//负责部分文件的抓取 \rN_CBM  
**FileSplitterFetch.java bT*4Qd4W  
*/ nRE}F5k  
package NetFox;
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&4%J35~  
[qI*]  
import java.io.*; '_&(Iwu  
import java.net.*; =Fs LF  
uE|[7,D7;u  
-$kJERvy  
public class FileSplitterFetch extends Thread { h9-Ky@X`  
k2WO*xa*  
x
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String sURL; //File URL B*AMo5  
long nStartPos; //File Snippet Start Position V$_0VN'+Z  
long nEndPos; //File Snippet End Position 6;b 'j\jG  
int nThreadID; //Thread's ID [;2:lbPx  
boolean bDownOver = false; //Downing is over D
vKM>P%|  
boolean bStop = false; //Stop identical ;VH]TKkk  
FileAccessI fileAccessI = null; //File Access interface <EUSl|6  
,qHG1#^  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 9]w0zUOL6  
{ :58'U|
 
this.sURL = sURL; ]VH@\ f  
this.nStartPos = nStart; 0EB'!  
this.nEndPos = nEnd; X]*/]Xx  
nThreadID = id; (j I|F-i  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 @iceMD.  
} 3d<HIG^W}  
4|L@oTzx  
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public void run() (KMobIP^  
{ I7_D $a=  
while(nStartPos < nEndPos && !bStop) \xZBu"  
{ j)DZmGg&t  
wE \c?*k  
MB 5[Js|  
try{ DQICD.X6R  
URL url = new URL(sURL); }\{1`$*~  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); vTEkh0Ys  
httpConnection.setRequestProperty("User-Agent","NetFox"); 79x9<,a)  
String sProperty = "bytes="+nStartPos+"-"; 7x]nY.\
 
httpConnection.setRequestProperty("RANGE",sProperty); {4 d$]o0V  
Utility.log(sProperty); A m1W<`  
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InputStream input = httpConnection.getInputStream(); ]e`_
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//logResponseHead(httpConnection); `4q}D-'TF8  
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PPO<{  
byte[] b = new byte[1024]; g
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int nRead; 15:@pq\  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) TjK5UML  
{ $I36>  
nStartPos += fileAccessI.write(b,0,nRead); yy1r,dw  
//if(nThreadID == 1) +"
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// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); PZR%8 m}]u  
} @b{u/:y  
&FVlTo1  
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Utility.log("Thread " + nThreadID + " is over!"); E|;5Z*  
bDownOver = true; &RrQ()<as  
//nPos = fileAccessI.write (b,0,nRead); O*{H;7Pv  
} !q\w"p0X  
catch(Exception e){e.printStackTrace ();} tuUXW5!/  
} ;T+U&U0d|  
} BZc-  
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Lp)
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//打印回应的头信息 {kH^
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public void logResponseHead(HttpURLConnection con) JW[\"`x!  
{ ;j>d"i36&  
for(int i=1;;i++) ;Hb[gvl  
{ 8m6nw0  
String header=con.getHeaderFieldKey(i); hb8XBBKR  
if(header!=null) r(T/^<  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); AS_+}*WSFQ  
Utility.log(header+" : "+con.getHeaderField(header)); _5w?v~65  
else
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break; [5*-V^m2  
} UjOhaj "h  
} |I5?5 J\  
s)8M? |[`I  
%,cFX[D/)  
public void splitterStop() A<5`[<x$  
{ yaLW(@  
bStop = true; xBfe8lor  
} pQ:P
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} aZ>\*1
 
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/* G1_@! 4  
**FileAccess.java DjzBG*f/  
*//文件访问(定位，写) \g1@A"  
package NetFox; -b0'Q  
import java.io.*; @dCPa7:>&  
}lTZq|;A  
-yQ\3wli`  
public class FileAccessI implements Serializable{ ^r_lj$:+$  
LA`VqJ  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 [ky6E*dV`  
RandomAccessFile oSavedFile; ![]I%'s  
long nPos; )c >B2
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public FileAccessI() throws IOException '
b?.\Bm;  
{ y2$;t'  
this("",0); Cm;qDvj+u  
} )USC  
]z=Vc#+!  
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public FileAccessI(String sName,long nPos) throws IOException  pl,Z  
{ n`z+ w*  
oSavedFile = new RandomAccessFile(sName,"rw"); &:CjUaP@  
this.nPos = nPos; k-pEBhOH  
oSavedFile.seek(nPos); CCh8
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} Y0B1xL@  
m?VRX.>  
m_"p$m;  
public synchronized int write(byte[] b,int nStart,int nLen) TBKd|D'H  
{ 2ZG1n#  
int n = -1; _|  
try{ -+=:+LhSMb  
oSavedFile.write(b,nStart,nLen); #H6g&)Z_  
n = nLen; @fH&(@  
} n?LIphc
\  
catch(IOException e) =8~R$z%  
{ YqSXi~.  
e.printStackTrace (); gGX0+L@E  
} _/ }6  
]AA%J@  
U\Ar*b)/T  
return n; bLM"t0  
}
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,#bb8+z&p  
} 1.0!H.>q  
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.y7)XLC  
/* DqzA U7  
**SiteInfoBean.java .?0>5-SfY  
*/ q|u8CX  
package NetFox; \_*MJ)h)X  
TA0D{
  
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public class SiteInfoBean { RzzFhU#r  
W8,tl>(  
SE^b0ZV*x  
private String sSiteURL; //Site's URL t+ S
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private String sFilePath; //Saved File's Path Sq-3-w,R~  
private String sFileName; //Saved File's Name 3IK(f.  
private int nSplitter; //Count of Splited Downloading File %7]XW2u  
U$A7EFK'  
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public SiteInfoBean() D!RE-w92X  
{//nSplitter的缺省值为5 m@Ip^]9ry  
//default value of nSplitter is 5 fNqmTRu  
this("","","",5); 7SK3  
} %[nR|a<  
zvGK6qCk  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 9PKoNd^e  
{ H9~%#&fF  
sSiteURL= sURL; m(Y.X=E
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sFilePath = sPath; ~n/Aq*  
sFileName = sName; TmYP_5g:  
this.nSplitter = nSpiltter; Cfr<D3&,]  
JEsLF{  
L-z;:Ztk  
} \oB'  
M20Bc,VI  
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public String getSSiteURL() i-k >U}[%  
{ t$K@%yU2  
return sSiteURL; If-,c^i  
} f]ue#O   
_V& !4Zd9:  
;v1NL@w*  
public void setSSiteURL(String value) `c'  
{ $U>/i@D  
sSiteURL = value; _hy{F%}  
} ;+i'0$;*w  
5pM&h~M
 
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public String getSFilePath() _r\$NgJIM  
{ e"fN~`NhY  
return sFilePath; tyEPU^PM  
} I/O
n3"U%  
#v4LoNm  
sTtX$&Qu  
public void setSFilePath(String value) )u8*zwq  
{ 1yBt/
U2  
sFilePath = value; :xFu_%7  
} Qz@IK:B}  
oTCzYY  
`/O`OrZ1K  
public String getSFileName() 6Wpxp\  
{ WR/o @$/  
return sFileName; T-|9o|~z  
} U@6jOZ  
MzQ\rg_B7  
pb^,Qvnp  
public void setSFileName(String value) ]*N:;J  
{ V
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sFileName = value; >ZT& `E  
} OM.k?1%+M  
p}3NJV  
o"p^/'ri  
public int getNSplitter() c,y|c`T 2  
{ %MJL5  
return nSplitter; #?{qlgv<p  
} 
MA\m[h]  
=)I"wR"v$  
90/vJN  
public void setNSplitter(int nCount) A8pj~I/*-  
{ T[;;9z  
nSplitter = nCount; SY-ez91  
} i;o}o*=  
} I^~=,D  
{L@+(I  
0K<x=-cCB
 
/* .,3Zj /  
**Utility.java ^r
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*/ Rj[hhSx 2  
package NetFox; &<,SV^wag  
l~bKBz  
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public class Utility { 6HoqEku/Q  
[X,A'Q  
ugYw<  
public Utility() ^Q0&.hL@  
{ ]3*P:$Rq  
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~>V-*NT8  
} #s"851e  
q|5Q?t:,r  
//线程睡眠 5|ic3  
public static void sleep(int nSecond) 8-7dokg>  
{ RMoJz6^>  
try{ y 'OlQ2U  
Thread.sleep(nSecond); "EoDQT"0  
} /XcDYMKgh  
catch(Exception e) dY}pN"  
{ 2-++i:, g  
e.printStackTrace (); t|}O.u-&;~  
} aG%kmS&fv  
} 5m4DS:&  
(;aB!(_  
//日志 nV}8M  
public static void log(String sMsg) (}Sr08m  
{ >$\Bu]{1  
System.err.println(sMsg); z3a-+NjDm  
} }e 9!xA  
;54(+5pqx  
jM~Bu.7 i6  
public static void log(int sMsg) TyF{tuF  
{ nnNv0?>d(  
System.err.println(sMsg); V!4a*,Pz  
}
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} =SAV|  
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\m4T3fy  
/* '-vE%U@<  
**TestMethod.java #'@ilk/.  
*/ P z ?m>>#  
package NetFox; kbxg_UI;  
lWWP03er!  
V8hO8  
public class TestMethod { >3 l=*|9  
&D]p,  
m9$a"$c  
public TestMethod() )6{< i5nJ\  
{ ///xx/weblogic60b2_win.exe Nt]qVwUm'Y  
try{ )RN<GW'  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); i9rS6<
V'  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); +4et7  
SiteFileFetch fileFetch = new SiteFileFetch(bean); %,\=s.~1  
fileFetch.start(); xRum*}|4  
} !KcWH9  
catch(Exception e){e.printStackTrace ();} i|]7(z#OyI  
R(k}y,eh.`  
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} /b5>Qp  
2*[QZ9U[@  
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public static void main(String[] args) ESTM$k}X  
{ VO=!8Yx[  
new TestMethod(); qP3q  
} 7(bQ}mHl\  
} K R,z^9  
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