http断点续传简单实现（java)

/* # TC x8]F  
**SiteFileFetch.java KDwjck"5;  
*/ 8GV$L~i  
package NetFox;
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import java.io.*; qnv9?Xh  
import java.net.*; avykg(  
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public class SiteFileFetch extends Thread { \qi=Us|=  
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SiteInfoBean siteInfoBean = null; //文件信息Bean #:w/vk  
long[] nStartPos; //开始位置 ]f-< s,@  
long[] nEndPos; //结束位置 G;qC&7T  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 @q],pD  
long nFileLength; //文件长度 *" >ek k  
boolean bFirst = true; //是否第一次取文件 Bj;Fy9[yb  
boolean bStop = false; //停止标志 AnfJyltS  
File tmpFile; //文件下载的临时信息 W(1p0|WQ:  
DataOutputStream output; //输出到文件的输出流 Fla,#uB  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） Elh: %dr Q  
public SiteFileFetch(SiteInfoBean bean) throws IOException IdUMoLL?  
{ Y)g7 E"  
siteInfoBean = bean; ,X)0+DNsq  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); |wKZ-6  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); |u<qbl  
if(tmpFile.exists ()) 2W~,,$ G  
{ z#SBt`c  
bFirst = false; Pj8s;#~u  
read_nPos(); `<8~tS/. w  
} QR
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else qeb:n$  
{ /4<eI3Z  
nStartPos = new long[bean.getNSplitter()]; |/Am\tk#13  
nEndPos = new long[bean.getNSplitter()]; 0:@:cz=#*  
} x0?8AG%  
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} H"tS33  
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public void run() Y<#WC#3=  
{ 5Q^ L"&0  
//获得文件长度 ,pq<.?&E  
//分割文件 iXqc$!lTH  
//实例FileSplitterFetch Ma0_!|i  
//启动FileSplitterFetch线程 'bN\bbR  
//等待子线程返回 l=`)yc.  
try{ 8G?'F${`  
if(bFirst) 68kxw1xY  
{ !O-q13\Y  
nFileLength = getFileSize(); Ultx|qU  
if(nFileLength == -1) <bDjAVq  
{ tMad 2,:  
System.err.println("File Length is not known!"); KIps{_J[<  
} F=EAD3  
else if(nFileLength == -2) vS6}R5  
{ jW}n6w5  
System.err.println("File is not access!"); !t3)j>h:  
} 403%~  
else P>z k  
{ `Yn^ -W  
for(int i=0;i<nStartPos.length;i++) vHZw{'5y  
{ K8$Hg:Ky-/  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 4r\Sbh  
} KwlN  
for(int i=0;i<nEndPos.length-1;i++) ]0GOSh  
{ 6+_)(+c  
nEndPos = nStartPos[i+1]; U\&kT/6vh  
} ? }|;ai  
nEndPos[nEndPos.length-1] = nFileLength; 2fT't"gw  
} S)p{4`p%  
} &n|#jo(gS  
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//启动子线程 Sd2R$r  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; +*WE<4"!6  
for(int i=0;i<nStartPos.length;i++) HWx
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{ kzZtKN9Az  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), C0[Rf.*  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), @#c(4}^ <w  
nStartPos,nEndPos,i); f#pT6  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); w;vp X>  
fileSplitterFetch.start(); =iC5um:  
} [R)?93  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), N#Bg`:!  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); )#l &F$  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", hun LV8z  
nEndPos = " + nFileLength); a5{CkM&,(  
// fileSplitterFetch[nPos.length-1].start(); y
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[3>l^Q|#  
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//等待子线程结束 *r!1K!c  
//int count = 0; wh l)^D  
//是否结束while循环 W@GcE;#-  
boolean breakWhile = false; Sdz!J 1  
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while(!bStop) 12])``9  
{ ez%RWck  
write_nPos(); udX4SBq-pC  
Utility.sleep(500); CsS0(n(x  
breakWhile = true; y4$UPLm
  
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for(int i=0;i<nStartPos.length;i++) u`$,S&Er  
{ %?J\P@  
if(!fileSplitterFetch.bDownOver) 2/RK pl &  
{ Z%\9y]zs  
breakWhile = false; dt{|bQLu3  
break; P1]ucu_y,  
} -q[T0^eS  
} pOS:/~I3  
if(breakWhile) ;XSRG*3j~4  
break; t(VG#}  
?|Fu^eR%X  
"tBdz V  
//count++; 2GLq#")P  
//if(count>4) &_HSrU  
// siteStop(); W}EI gVHs  
} #M&rmKv)g  
@g(N!n~  
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System.err.println("文件下载结束！"); 6*cm  
} B3@  
catch(Exception e){e.printStackTrace ();} $]:I1I  
} 17tph;  
.qi$X!0  

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//获得文件长度 Za}*6N=?*  
public long getFileSize() w&f8AY)#]4  
{ kEf}yTy  
int nFileLength = -1; c!T^JZBb  
try{ HWT0oh]  
URL url = new URL(siteInfoBean.getSSiteURL()); 7
3
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); IhwJYPL
F  
httpConnection.setRequestProperty("User-Agent","NetFox"); 9~I\WjB "  
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P5*:r3>  
int responseCode=httpConnection.getResponseCode(); ,RKBGOz?f  
if(responseCode>=400) I7r{&X) D  
{ 
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processErrorCode(responseCode); w-FZ`OA`D  
return -2; //-2 represent access is error  g2L  
} AT}}RE@vq  
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String sHeader;
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for(int i=1;;i++) U2 <*BRJ  
{ `* "u"7e  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); J0a]Wz%  
//Utility.log(in.readLine()); Z2)f$ c  
sHeader=httpConnection.getHeaderFieldKey(i); Q2cF++Q1  
if(sHeader!=null) &{9'ylv-B)  
{ LG'JQGl5  
if(sHeader.equals("Content-Length")) I.r&;  
{ X5U_|XK6Y  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); QG?7L_I  
break; sqi~j(&\1  
} GRCc<TM,U  
} }X$vriW  
else *_`T*$  
break; \NhCu$'  
} GK)3a 9;  
} @k<RX'~q  
catch(IOException e){e.printStackTrace ();} k^Zpb&`Hx  
catch(Exception e){e.printStackTrace ();} v]F q}I"  
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Utility.log(nFileLength); nQdNXv<(  
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return nFileLength; `IOp*8  
} )MZ]c)JD^  
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//保存下载信息（文件指针位置） Hj |~*kG  
private void write_nPos() V]L$
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{ I+D`\OSL  
try{ KSIH1E  
output = new DataOutputStream(new FileOutputStream(tmpFile)); s=(~/p#M  
output.writeInt(nStartPos.length); #i-!:6sLA  
for(int i=0;i<nStartPos.length;i++) m?'5*\(ST  
{ bR?-B>EB  
// output.writeLong(nPos); Xx[ LK  
output.writeLong(fileSplitterFetch.nStartPos); p|,K2^?Y  
output.writeLong(fileSplitterFetch.nEndPos); auAST;"Z8  
} 0(|R NV_  
output.close(); K~<pD:s  
} =x>z|1  
catch(IOException e){e.printStackTrace ();} 1)?^N`xF  
catch(Exception e){e.printStackTrace ();} V[wEn9   
} H1| -f]!  
*U.$=4Az  
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//读取保存的下载信息（文件指针位置） jec03wH_0  
private void read_nPos() cCFSPT2fq[  
{ k^Tu9}[W1  
try{ :>nk63
V (  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ioi0^aM  
int nCount = input.readInt(); Vx
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nStartPos = new long[nCount]; 1@yXVD/  
nEndPos = new long[nCount]; '&Q_5\Tn  
for(int i=0;i<nStartPos.length;i++) g,Kb9['  
{ _Jk-nZgn  
nStartPos = input.readLong(); SOb17:o3|  
nEndPos = input.readLong(); $JqdI/
s  
} tirw{[X0n  
input.close(); [T"oqO4%]  
} Vm'ReH  
catch(IOException e){e.printStackTrace ();} ~ i1w,;(  
catch(Exception e){e.printStackTrace ();} l"}W $3]u$  
} }!0,(<EsV  
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private void processErrorCode(int nErrorCode) o%h\55S  
{ B5#a 4G.  
System.err.println("Error Code : " + nErrorCode); UL;d H  
} KZ ?<&x  
6Kh:m-E9  
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//停止文件下载 zF;}b3oIo  
public void siteStop() Z{chAg\
 
{ 0vS%m/Zi-  
bStop = true; \4K8*`$  
for(int i=0;i<nStartPos.length;i++) b6bmvHD  
fileSplitterFetch.splitterStop(); Mki(,Y|1~  
.}ohnnJB0  
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} KK(x)(  
} ;&
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//负责部分文件的抓取 }tft@,dIC  
**FileSplitterFetch.java Xu3^tH-b<  
*/ _M:)x0("  
package NetFox; dLD"Cx  
a&#Z=WK4  
eQcy'GA06  
import java.io.*; A&$!s)8z  
import java.net.*; H b]   
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public class FileSplitterFetch extends Thread { <$UMMA  
cIl^5eE^Pq  
;ZjQy,H%  
String sURL; //File URL RduA0@g0  
long nStartPos; //File Snippet Start Position (d^pYPr{  
long nEndPos; //File Snippet End Position ~S|Vd  
int nThreadID; //Thread's ID CEYHD?9k8  
boolean bDownOver = false; //Downing is over [+{ ot   
boolean bStop = false; //Stop identical s7FqE>#c0  
FileAccessI fileAccessI = null; //File Access interface n+zXt?{u  
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+/\.%S/  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 5tP0dQYd
 
{ `U2PlCf|  
this.sURL = sURL; |t]-a%A=w  
this.nStartPos = nStart; 3(^9K2.s}  
this.nEndPos = nEnd; lxbbyy25  
nThreadID = id; PwF}yxkI  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 x18ei@c  
} b44H2A.  
cJ!wZT`  
70HEu@-  
public void run() d#ld*\|  
{ 8k_,Hni  
while(nStartPos < nEndPos && !bStop) @=Ly#HuUM  
{ umrRlF4M;  
<6dD{{J]>p  
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try{ YvBUx#\  
URL url = new URL(sURL); 1(q!.lPc  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); H1\~T  
httpConnection.setRequestProperty("User-Agent","NetFox"); C9gF2ii|?  
String sProperty = "bytes="+nStartPos+"-"; deHBY4@  
httpConnection.setRequestProperty("RANGE",sProperty); +]uy  
Utility.log(sProperty); !G\1$"T$  
8"oS1W  
{:6VJ0s\  
InputStream input = httpConnection.getInputStream(); Vy}:Q[  
//logResponseHead(httpConnection); >/e#Z h  
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byte[] b = new byte[1024]; qf)
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int nRead; 9!bD|-6y  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ((.PPOdJV  
{ gl]{mUZz}  
nStartPos += fileAccessI.write(b,0,nRead); %*|XN*iXC  
//if(nThreadID == 1) yc%AkhX*  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 14oD^`-t  
} fD,#z&  
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>kC@7h5)  
Utility.log("Thread " + nThreadID + " is over!"); eWwSD#N#  
bDownOver = true; kdxs{b"t  
//nPos = fileAccessI.write (b,0,nRead); >#!n"i;  
} .WyI.Y1  
catch(Exception e){e.printStackTrace ();} HD=WHT&  
} JG/sKOlA  
} 1-w1k^e  
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//打印回应的头信息 O "{o (  
public void logResponseHead(HttpURLConnection con) Em4TEv  
{ xFg=Tyq:  
for(int i=1;;i++) L?al2aopF  
{ ~0/=5 dC  
String header=con.getHeaderFieldKey(i); ld9zOq  
if(header!=null) .YS[Md{  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); LgBs<2  
Utility.log(header+" : "+con.getHeaderField(header)); /x$jd)C  
else o"[qPZd>  
break; OY[N%wr!  
} 7F+f6(hB  
} %eD&2$q*  
 4jG@ #  
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public void splitterStop() R?l>
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{
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bStop = true; /8Vh G|Wb  
} !*CL>}-,  
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} VaX>tUW  
c?IIaj!  
c!kbHZ<Z  
/* i~K~Czmok+  
**FileAccess.java 4{fi=BA   
*//文件访问(定位，写) #lJF$  
package NetFox; =q6yb@  
import java.io.*; |W#^L`!G  
{?5EOp~  
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public class FileAccessI implements Serializable{ &3u* zV$  
61gZZM  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 V]vk9M2q[l  
RandomAccessFile oSavedFile; `^_.E:f  
long nPos; ;| \Ojuf  
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[dt1%DD`M  
public FileAccessI() throws IOException ~
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{ c-s ~q/  
this("",0); ->93.sge  
} snj+-'4T  

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public FileAccessI(String sName,long nPos) throws IOException {a(YV\^y|H  
{ D, 3x:nK  
oSavedFile = new RandomAccessFile(sName,"rw"); Y9PG  
this.nPos = nPos; 6'qs=Ql  
oSavedFile.seek(nPos);  wl9E  
} u
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public synchronized int write(byte[] b,int nStart,int nLen) (a)d7y.oo  
{ kyY tL_SD  
int n = -1; RYvS,hf6z  
try{ 4;&(  
oSavedFile.write(b,nStart,nLen); 8c~b7F \  
n = nLen; ~G"6^C:x  
} E-!`6  
catch(IOException e) 6oJ~Jdn'  
{ ZEApE+m  
e.printStackTrace (); ?[VS0IBS  
} >TtkG|/U-T  
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return n; meIY00  
} L{\B9b2  
$=H\#e)]Ug  
(<3'LhFII  
} {){i ONd  
8[zP2L!-  
]1p&*xX:Bj  
/* }hl# e[$  
**SiteInfoBean.java !@*Ac$J>$  
*/ wAy;ZNu  
package NetFox; ^iTjr$hQ;  
>gVR5o  
srC'!I=s>8  
public class SiteInfoBean { f#mY44:,C  
TQnMPELh"  
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private String sSiteURL; //Site's URL ^
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private String sFilePath; //Saved File's Path 'MsxZqW"~  
private String sFileName; //Saved File's Name 4pA(.<#A  
private int nSplitter; //Count of Splited Downloading File 5GpRN  
lfWxdi  
*[_?4*F  
public SiteInfoBean() <EpP;  
{//nSplitter的缺省值为5 bCE[oi6hb  
//default value of nSplitter is 5 !&19%C4  
this("","","",5); "-^TA_XfI  
} L! Q&?xP  
ZRcY; ?  
}vcC4 =t/  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) KZ<
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{ +]*?J1Y8Z  
sSiteURL= sURL; rEZa%)XJ  
sFilePath = sPath; WXXLD:gxI  
sFileName = sName; M[Ls:\1a  
this.nSplitter = nSpiltter; j7O7P+DmS  
#msk'MVt  
i}M&1
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} [Ma&=2h  
&HW%0lTs%  
I_eYTy-a`1  
public String getSSiteURL() CXJ0N  
{ Ku&0bXP  
return sSiteURL; 6C) G  
} +h[$\_y  
5H?`a7q N  
@\[&_DZ  
public void setSSiteURL(String value) gxL5%:@  
{ HiVF<tN  
sSiteURL = value; |\Qr cf  
} :2  
g^8bY=* .  
0y|}}92:  
public String getSFilePath() Vk>aU3\c  
{ 9j9A'Y9(  
return sFilePath; }U+gJkY2  
} j1<@*W&b  
GD.mB[f*  
nvpdu)q<  
public void setSFilePath(String value) RI cA)I.  
{ ~vaV=})  
sFilePath = value; Fc42TH p  
} [nYwJ  
IXX^C}\,  
H}JH339  
public String getSFileName() Gl}=Q7  
{ js7J#b7  
return sFileName; CWt,c
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} y]M/oH  
E jBEZL|_  
mKWA-h+f  
public void setSFileName(String value) g8}/Ln*W'  
{ vZ$uD,@;.  
sFileName = value; _0^<)OSY  
} 6}{2W<  
Jp_{PR:&  
F]SexP4:A  
public int getNSplitter() E}\^GNT  
{ QT\S>}  
return nSplitter; sStaTR{  
} $eRxCX?b2  

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public void setNSplitter(int nCount) +<@7x16  
{ %E~4Ur  
nSplitter = nCount; 3(6i6 vV  
} [0F+t,`  
} "YHe]R>3s  

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Yq<D(F#qx  
/* :]e:-JbT4z  
**Utility.java OFCkQEG=y>  
*/ Q
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package NetFox; ;STO!^9~  
|~rDEv3  
L{'qZ#N[  
public class Utility { >0:h(,?V  
<k/'mBDk  
u|9^tHT>  
public Utility() rWi
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{ L=4?vs  
~F>oNbJIv  
u.8vXc  
} )v8;\1`s:  
u ldea)  
//线程睡眠 w0tlF:Eg  
public static void sleep(int nSecond) c3i|q@ k  
{ e+4p__TmZ  
try{ D@5&xd_@4  
Thread.sleep(nSecond); : bT*cgD{  
} 8r)eiERv  
catch(Exception e) GAtK1%nPD  
{ mmr>"`5.  
e.printStackTrace (); ,LWM}L  
} lb`P9mbr+  
} x-CYG?-x  
=<O{  
//日志 6i%LM`8GEk  
public static void log(String sMsg) a%Cq?HZ7  
{ / D#vs9S  
System.err.println(sMsg); 241YJ  
} SU2(XP]5  
M+)%gnq`u  
QH~/UnV  
public static void log(int sMsg) $:/y5zi  
{ 6SlE>b9tA  
System.err.println(sMsg); 0!_D M^3  
} }+i ZY\t  
} SX/yY  
X& O o1y  
z=BX-)  
/* i LK8Wnrq  
**TestMethod.java l yO_rZT  
*/ B2WPjhzD  
package NetFox; w0^(jMQe^  
*G>V`||RW  
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public class TestMethod { <74q]C
 
=@gH$Q_1  
?VS {,"X  
public TestMethod() wC'KI8-  
{ ///xx/weblogic60b2_win.exe UQ`%,D  
try{ 8X5;)h   
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); n*@^c$&P  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); /o+, =7hY  
SiteFileFetch fileFetch = new SiteFileFetch(bean); J>]' {!+  
fileFetch.start(); +7N6]pK|"  
} ZCbxL.fFz  
catch(Exception e){e.printStackTrace ();} !+9H=u  
.I {X  
Ai(M06P:h  
} IP&En8W+  
>OZ+k(saL  
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public static void main(String[] args) #x)G2T'?  
{ V{ra,a*  
new TestMethod(); H<X4R  
} P}DrUND  
} L1P]T4a@)  
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