http断点续传简单实现（java)

/* Qw"%Xk  
**SiteFileFetch.java \J;]g\&I"  
*/ l&mY}k  
package NetFox; v0bP|h[t  
import java.io.*; HV]u9nrt#  
import java.net.*; 9Sa6v?sRor  
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public class SiteFileFetch extends Thread { 7&w[h4Lw  
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SiteInfoBean siteInfoBean = null; //文件信息Bean g@>93j=cZU  
long[] nStartPos; //开始位置 myd:"u,}9  
long[] nEndPos; //结束位置 0bSnD|#I  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 rd=+[:7L  
long nFileLength; //文件长度 Gq%,'amf  
boolean bFirst = true; //是否第一次取文件 /#q6.du  
boolean bStop = false; //停止标志 FJ{&R Ld  
File tmpFile; //文件下载的临时信息 hx4c`fOs  
DataOutputStream output; //输出到文件的输出流 I SdB5Va  
Im]6-#(9\|  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） @~&^1%37)  
public SiteFileFetch(SiteInfoBean bean) throws IOException EN8xn9M?  
{ D^U?!S&4~  
siteInfoBean = bean; fhC|=0XB  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 8KKhD$  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); k 6i&NG6  
if(tmpFile.exists ()) Jc`tOp5  
{ x0%@u^BF  
bFirst = false; 5{vuN)K3  
read_nPos(); 0h{&k7T<7  
} GNHWbC6_m  
else |8)\8b|VuC  
{
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nStartPos = new long[bean.getNSplitter()]; {K:]dO  
nEndPos = new long[bean.getNSplitter()]; F%O+w;J4  
} 6* 0vUy*"  
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} r8[)Ccv  
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public void run() ~]'yUd1gSZ  
{ gg Nvm  
//获得文件长度 *D1vla8  
//分割文件 1(e64w@  
//实例FileSplitterFetch L@ejFXQg  
//启动FileSplitterFetch线程 \Xr*1DI<  
//等待子线程返回 jx ?"`;a  
try{ b&AeIU}&  
if(bFirst) VssW
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{ K}'?#a(aX=  
nFileLength = getFileSize(); Y.#fpG'  
if(nFileLength == -1) 10bv%ZX7  
{ ktp<o.f[  
System.err.println("File Length is not known!"); 8PWEQ<ev7>  
} HK%W7i/k@  
else if(nFileLength == -2) g0-rQ
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{ )l`VE_(|  
System.err.println("File is not access!"); /a6i`  
} 2@I0p\a  
else #u +~ ^M  
{ HuQdQ*Q  
for(int i=0;i<nStartPos.length;i++) ?0qP6'nWx  
{ \m:('^\6o  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); . lNf.x#u  
} WF2t{<]^e  
for(int i=0;i<nEndPos.length-1;i++) Dt iM}=:  
{ 0]^gT'  
nEndPos = nStartPos[i+1]; o%0To{MAF-  
} oa`7ClzD  
nEndPos[nEndPos.length-1] = nFileLength; ~@T`0W-Py  
} i)$<j!L  
} Wv~&Qh}  
b #Llu$  
Lg|d[*;'7  
//启动子线程 /w2-Pgm-[\  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; o8NRu7@?  
for(int i=0;i<nStartPos.length;i++) 9n"MNedqH  
{ )CgH|z:=b  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), imKMPO=  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), <Pi#-r.,  
nStartPos,nEndPos,i); .1_kRy2*.  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); \^jRMIM==  
fileSplitterFetch.start(); wyXQP+9G  
} @rF|WT  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ~=|QPO(d  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); J93xxj  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", t6lwKK  
nEndPos = " + nFileLength); x0)WrDb  
// fileSplitterFetch[nPos.length-1].start(); r\)bN4-g  
cmU>A721  
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//等待子线程结束 }<*KM)%  
//int count = 0; tf[)| /M  
//是否结束while循环 3Vak C  
boolean breakWhile = false; QX-n l~  
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while(!bStop) pbw{Ez
M  
{ {-%8RSK=<  
write_nPos(); _rmKvSD%  
Utility.sleep(500); RaP,dR+P  
breakWhile = true; Ys&)5j-  
;k,@^f8  
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for(int i=0;i<nStartPos.length;i++) 2gR*]?C*  
{ 1+YqdDqQ  
if(!fileSplitterFetch.bDownOver) ydAiH*>  
{ `PSjkF(  
breakWhile = false; 2<n@%'OQp  
break; aPQxpK?  
} g!9|1z  
} l[rK)PM  
if(breakWhile) I0!]J{  
break; <1 ;pyw y  
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//count++; C7DwA/$D  
//if(count>4) <XN=v!2;  
// siteStop(); ]'-y-kqY  
} n7yp6Db  
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ml /S|`Drk  
System.err.println("文件下载结束！"); HxcL3Bh$~}  
} ,]]*
}4[r  
catch(Exception e){e.printStackTrace ();} K9y~ e  
} 1Kd6tnX  
&HtTh {  
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//获得文件长度 W|y;Kxy  
public long getFileSize() 5pK _-:?  
{ 0G0(g,3p  
int nFileLength = -1; Rd|8=`)  
try{ OHrzN']  
URL url = new URL(siteInfoBean.getSSiteURL()); z,4 D'F&  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); oR/_{#Mz"  
httpConnection.setRequestProperty("User-Agent","NetFox"); \ Ce
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h  
}}D32TVN  

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int responseCode=httpConnection.getResponseCode(); tw&v@HUP  
if(responseCode>=400) 5$+ssR_?k  
{ F\|4zM  
processErrorCode(responseCode); =%7s0l3z  
return -2; //-2 represent access is error b6p'%;Y/  
} , 2xv  
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String sHeader; ,>8w|951'  
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for(int i=1;;i++) 1hE{(onI  
{ N_Kdi%q  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); z?( b|v  
//Utility.log(in.readLine()); x0:BxRx*  
sHeader=httpConnection.getHeaderFieldKey(i); 5t"FNL <(M  
if(sHeader!=null) DfP-(Lm)  
{ c&FOt  
if(sHeader.equals("Content-Length")) !a-B=pn!]  
{ aB?usVoS  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); aT(_c/t.  
break; #sDb611}#  
} qmt9J?$k  
} v(!:HK0oeT  
else YRFz]  
break; B?- poB&  
} - l^3>!MAM  
} 6bLn8UT  
catch(IOException e){e.printStackTrace ();}  qLP/z  
catch(Exception e){e.printStackTrace ();} rNTLP m  
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.  
Utility.log(nFileLength); KIag(!&  
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return nFileLength;
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} Y#tur`N  
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//保存下载信息（文件指针位置） FROC/'  
private void write_nPos() >%0$AW|Exu  
{ K,$rG%czX  
try{ n|LpM.  
output = new DataOutputStream(new FileOutputStream(tmpFile)); A`ajsZ{q,  
output.writeInt(nStartPos.length); -]H~D4ng  
for(int i=0;i<nStartPos.length;i++) "aCAA#$J  
{ 7B (%2  
// output.writeLong(nPos); x+pf@?w  
output.writeLong(fileSplitterFetch.nStartPos); 2\QsF,@`YU  
output.writeLong(fileSplitterFetch.nEndPos); Dfa3&##{  
} ?%
}!_F`h%  
output.close(); 0GXY2+p}S  
} .V?[<}OJn  
catch(IOException e){e.printStackTrace ();} 8/BMFRJ  
catch(Exception e){e.printStackTrace ();} lM{fld  
} xZlCFu 
 
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//读取保存的下载信息（文件指针位置） |E.BGdS  
private void read_nPos() [nPs  
{ 5<R m{  
try{ [!-gb+L  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); V?1 $H  
int nCount = input.readInt();  1/2cb-V  
nStartPos = new long[nCount]; Z>Mv$F"p:  
nEndPos = new long[nCount]; cgSN:$p(R  
for(int i=0;i<nStartPos.length;i++) _Uq' N0U  
{ <.B+&3
')  
nStartPos = input.readLong(); $[n:IDa*@1  
nEndPos = input.readLong(); }$4z$&  
} >[,eK=  
input.close(); v|o{AL:ei  
} ~~Ezt*lH  
catch(IOException e){e.printStackTrace ();} ]MosiMJF  
catch(Exception e){e.printStackTrace ();} h0@a"Dq
K  
} %.<_+V#h  
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private void processErrorCode(int nErrorCode) PD-&(ka.  
{ -6HwGfU  
System.err.println("Error Code : " + nErrorCode); }: HG)V  
} .'gm2  
'=n?^EPE3  
4^F%bXJ)  
//停止文件下载 Oo}h:3?  
public void siteStop() pB
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{ /uj^w&l#  
bStop = true; *}d N.IL,  
for(int i=0;i<nStartPos.length;i++) J-5>+E,nZ  
fileSplitterFetch.splitterStop(); 8Auek#[  
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} y]m: {  
} @wI>0B  
//负责部分文件的抓取 ExS5RV@v'  
**FileSplitterFetch.java Jf
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*/ MK=oGzK  
package NetFox; _9 ]:0bDUo  
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import java.io.*; \7r0]& _  
import java.net.*; Wye* ~t  
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public class FileSplitterFetch extends Thread { 5M0Q'"`F:  
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String sURL; //File URL f +{=##'0  
long nStartPos; //File Snippet Start Position gwRB6m$  
long nEndPos; //File Snippet End Position q"u,Tnc;  
int nThreadID; //Thread's ID A iM ukd,  
boolean bDownOver = false; //Downing is over i}sAF/  
boolean bStop = false; //Stop identical fY[Fwjj3  
FileAccessI fileAccessI = null; //File Access interface 1^![8>u"  
^w60AqR8  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException L7-BuW}&  
{ 1 :p'  
this.sURL = sURL; h*k V@Dc  
this.nStartPos = nStart; oS fr5 i  
this.nEndPos = nEnd; d_@ E4i  
nThreadID = id; Sfz1p  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 J rx^  
} )8@-  
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public void run() r ;RYGLx  
{  AG@gOm  
while(nStartPos < nEndPos && !bStop) c>_ti+  
{ Hd|[>4Z  
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try{  ES~b f  
URL url = new URL(sURL); rexv)!J  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); d_yvG.#C  
httpConnection.setRequestProperty("User-Agent","NetFox"); aDF@AS  
String sProperty = "bytes="+nStartPos+"-";
@:C)^f"  
httpConnection.setRequestProperty("RANGE",sProperty); :>0ywg  
Utility.log(sProperty); Lq2Q:w'  
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InputStream input = httpConnection.getInputStream(); &<VU}c^!  
//logResponseHead(httpConnection); |LZ;2 i  
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byte[] b = new byte[1024]; j
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int nRead; |nefg0`rk  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Vp/XVyL}R  
{ i%K6<1R;y{  
nStartPos += fileAccessI.write(b,0,nRead); 3^7+fxYWo  
//if(nThreadID == 1) oMQ4q{&|  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); z1J)./BO  
} >1j#XA8  
1=R$ RI  
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Utility.log("Thread " + nThreadID + " is over!"); 4X+xh|R:U  
bDownOver = true; TEz;:*,CG  
//nPos = fileAccessI.write (b,0,nRead); atTR6%!6  
} L 4j#0I]lq  
catch(Exception e){e.printStackTrace ();} "cKD#  
} 3W?7hh  
} 8RMM97@1Q  
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v`A)GnNiN  
//打印回应的头信息 |OH*c3~r  
public void logResponseHead(HttpURLConnection con) rmX*s}B  
{ Hd~g\  
for(int i=1;;i++) /mkT7,]  
{ a{kJ`fK   
String header=con.getHeaderFieldKey(i); wQ+pVu?6_  
if(header!=null) .-Lrrk)R+  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); |Ea%nghl  
Utility.log(header+" : "+con.getHeaderField(header)); Bl b#h  
else \l GD8@,x  
break; ^Arv6kD,  
} `MI\/o
M@  
} tbS hSbj  
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public void splitterStop() 4 Ej->T.  
{ TKB8%/_p  
bStop = true; !85bpQ.  
} b Hr^_ogN  
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} $${I[2R)  
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g *Js4  
/* Cbff:IP  
**FileAccess.java oco,sxT  
*//文件访问(定位，写) z!g$#hmL>  
package NetFox; \s)MNs  
import java.io.*; pJHdY)Cz  
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public class FileAccessI implements Serializable{ cW%)C.M  
[G}dPXD  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 wn[)/*(,$(  
RandomAccessFile oSavedFile; L$PbC!1  
long nPos; `+,?%W)  
L`nW&;w'  
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public FileAccessI() throws IOException j\ y!  
{ 0AO^d[v  
this("",0); /8l-@P.o  
} +=($mcw#[  
"'v+*H 3  
s<YN*~  
public FileAccessI(String sName,long nPos) throws IOException Lf9hOMHx  
{ Ey=2zo^F  
oSavedFile = new RandomAccessFile(sName,"rw"); f;'*((  
this.nPos = nPos; *u+DAg'&  
oSavedFile.seek(nPos); |Hf|N$  
} lh;fqn`  
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public synchronized int write(byte[] b,int nStart,int nLen) 1/-3m P
o  
{ %0Ur3  
int n = -1; &~_F2]oM  
try{ -}6ew@GE  
oSavedFile.write(b,nStart,nLen); IW\^-LI.  
n = nLen; _[6sr7H!  
} 3yx[*'e$  
catch(IOException e) ljbAfd  
{ 1V2]@VQF  
e.printStackTrace (); |=q~X}DA  
} M(C">L]8  
);!ND%  
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return n; Q:P)g#suc  
} tD.#*.7  
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} lj<Sa  
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/* =;Q/bD->  
**SiteInfoBean.java $z$^ yjL  
*/ $@
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package NetFox; cSPQ NYU:  
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public class SiteInfoBean { 9QU\J0c/  
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private String sSiteURL; //Site's URL v< P0f"GH  
private String sFilePath; //Saved File's Path ta?NO{*  
private String sFileName; //Saved File's Name `4K|L6  
private int nSplitter; //Count of Splited Downloading File F~Dof({:  
GQ1/pys  
e=&~6bs1U  
public SiteInfoBean() ~xqiasE#K  
{//nSplitter的缺省值为5 &PJ;B)b  
//default value of nSplitter is 5 !.UE}^TV  
this("","","",5); $`lWW6>P  
} W`x.qumN
 
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) znrO~OK  
{ {F<0e^*  
sSiteURL= sURL; ZLzc\>QX  
sFilePath = sPath; D&FDPaJM  
sFileName = sName; n3p@duC4  
this.nSplitter = nSpiltter; )%^l+w+&  
h\!8*e;RAW  
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} 6/<Hx@r (  
0d+n[Go+S  
f&CQn.K"  
public String getSSiteURL() O[d#-0s  
{ gY7sf1\wX  
return sSiteURL; EK# 11@0%  
} Phi5;U!  
QD7KE6KP'  
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public void setSSiteURL(String value) M0$MK>  
{ %np(z&@wi  
sSiteURL = value; WK$\#>T  
} 3VLwY!2:  
?kR1T0lKkE  
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public String getSFilePath() WVR/0l&bU  
{ a{xJ#_/6  
return sFilePath; qy'-'UlIr  
} {dxFd-K3  
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public void setSFilePath(String value) ,\i*vJ#f  
{ ~Eg]Auk7  
sFilePath = value; E_~e/y"-  
} CT'4.  
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public String getSFileName() _
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{ 6rnFXZ\  
return sFileName; Md4Q.8  
} ?EC\.{  
'1D$ ;  
1 3]e< '  
public void setSFileName(String value) *IOrv)
 
{ X|\`\[  
sFileName = value; :;_}Gxx  
} B& @ pZYl  
@RPQ1da  
AZ(zM.y!#_  
public int getNSplitter() BI%^7\HZ  
{ {#kCqjWG  
return nSplitter; I3 "6"  
} z]9t 5I  
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public void setNSplitter(int nCount) /k/X[/WO  
{ m}z6Bbis0  
nSplitter = nCount; -
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} q;[HUyY,  
} a]*{!V{$i  
x_~_/&X5  
z6)N![X  
/* UJ,vE}=_{  
**Utility.java oaQW~R`_  
*/ f+9WGNpw  
package NetFox; E"'u2jEG^  
-Kg.w*\H7/  
#M~yt`R~  
public class Utility { +\ftSm>  
s=:)!M.i  
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public Utility() [s$x"Ex  
{ ?;oJ=.T  
MB;rxUbhe3  
B>1,I'/$.  
} (W#CDw<ja  
FaCW +9B  
//线程睡眠 07Yak<+~  
public static void sleep(int nSecond) w)|9iL8  
{ pfZ[Y
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try{ ]A}ZaXd  
Thread.sleep(nSecond); '4M{Xn}@  
} m!KEK\5M?  
catch(Exception e) NxF:s,a6  
{ g$NUu  
e.printStackTrace (); x:0swZ5Z  
} AM=> P7  
} d;<'28A  
F5X9)9S  
//日志 : jkO  
public static void log(String sMsg) G>"n6v'^d  
{ OCu_v%G0  
System.err.println(sMsg); gbYM1guiD  
} FS5iUH+5  
=~JVU  
2OpA1$n6  
public static void log(int sMsg) x"sbm  
{ D7nK"]HG;l  
System.err.println(sMsg); a&0g0n6  
} pq r_{  
} cBqbbZyUk  
/:]<z6R  
U\Y0v.11  
/* L+G0/G}O\  
**TestMethod.java I(AlRh  
*/ ZxSnqbyA*  
package NetFox; QDW,e]A  
SW%}S*h  
5eL b/,R  
public class TestMethod { Y2tVq})!  
#/ePpSyD  
c*B< - l<5  
public TestMethod() mS[``$Z\!  
{ ///xx/weblogic60b2_win.exe #lMcAYH,  
try{ Q9AvNj>X  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); x2t&Wpvt  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); sN8pwRjb  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ##BbR  
fileFetch.start(); DN)o|p  
} wbJBGT{sm  
catch(Exception e){e.printStackTrace ();} `Y.~eE  
&lU\9  
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} 9]Ue%%vM  
h STcL:b   
;o'r@4^&$R  
public static void main(String[] args) CyLwCS{V\  
{ d+G%\qpzQ  
new TestMethod(); @:RoYvk$  
} D
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} h2x9LPLBxT  
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