http断点续传简单实现（java)

/* HYtkSsXLN  
**SiteFileFetch.java ^ c:(HUo#  
*/ \jC}>9  
package NetFox; 4Vt YR  
import java.io.*; mI l_ [  
import java.net.*; yfq"atj  
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public class SiteFileFetch extends Thread { hhwV)Z  
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SiteInfoBean siteInfoBean = null; //文件信息Bean nU/v(lN  
long[] nStartPos; //开始位置 zd+8fP/UB  
long[] nEndPos; //结束位置 W8\K_M}  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 "8s0~[6S  
long nFileLength; //文件长度 *.20YruU;j  
boolean bFirst = true; //是否第一次取文件 -O{Af  
boolean bStop = false; //停止标志 =3sBWDB[  
File tmpFile; //文件下载的临时信息 &K}!R$[,:P  
DataOutputStream output; //输出到文件的输出流 #Ez>]`]TB  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ,!c.  
public SiteFileFetch(SiteInfoBean bean) throws IOException 8K{ TRPy  
{ 5pz%DhjLo  
siteInfoBean = bean;
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//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); @HR]b
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tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); \4mw>8wA  
if(tmpFile.exists ()) i_V~SC`  
{ 55fV\3F|R  
bFirst = false; C^.:{  
read_nPos(); R5qC;_0cV  
} "GgK,d}%  
else MOdodyG  
{ 3:!+B=woR  
nStartPos = new long[bean.getNSplitter()]; \6*3&p  
nEndPos = new long[bean.getNSplitter()]; nx=Zl:Q}  
} 3nxJ`W5j  
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} u3Ua>A-  

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public void run() GV* B$  
{ ?> }bg  
//获得文件长度 rj<r6  
//分割文件 Kt9:V,  
//实例FileSplitterFetch On#RYy^}  
//启动FileSplitterFetch线程 q*,];j/>k  
//等待子线程返回 YcT!`B  
try{ &ciU`//`  
if(bFirst) ]k5l]JB  
{ 8I3"68c_a  
nFileLength = getFileSize(); <S%M*j  
if(nFileLength == -1) -Y{P"!p0  
{ nUD)G<v
 
System.err.println("File Length is not known!"); d0eMDIm3R\  
} | x/,  
else if(nFileLength == -2) $Ic: c  
{ l}># p'$  
System.err.println("File is not access!"); Y;4nIWe JL  
} >#<o7]  
else fHdPav f,S  
{ )EcE{!H6+  
for(int i=0;i<nStartPos.length;i++) Ag^Cb'3X  
{ z`]'~  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Yu`b[]W  
} t L}i%7  
for(int i=0;i<nEndPos.length-1;i++) Y&'Bl$`  
{ 4#!NVI3t  
nEndPos = nStartPos[i+1]; 5Z,^46J  
} W/OZ}ky}^  
nEndPos[nEndPos.length-1] = nFileLength; ](vOH#E  
}  Q47Rriw  
} +v{<<  
@;!s"!~sv  
"JT R5;`w  
//启动子线程 ggIz)</  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; uAwT)km {  
for(int i=0;i<nStartPos.length;i++) );'8*e'  
{ C AVqjT7  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), fE8/tx](  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), iZyhj%#  
nStartPos,nEndPos,i); LcI,Dy|P  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 76(-!Z@=J  
fileSplitterFetch.start(); TU&gj1  
} 17 Hdj  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), O|}97a^  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 8(&Jy RT  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", icOh/G=N;  
nEndPos = " + nFileLength); =Wn11JGh  
// fileSplitterFetch[nPos.length-1].start(); be}^
}w=  
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h/W@R_Y  
//等待子线程结束 wz3BtCx  
//int count = 0; Ox#%Dm2  
//是否结束while循环 ^&>(_I\w.6  
boolean breakWhile = false; UEbRg =6  
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while(!bStop) ;9MsV.n  
{ OQIQ   
write_nPos(); bsO7
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Utility.sleep(500); v,#*%Gn`%  
breakWhile = true; =yJJq=!  
>vF=}1_L  
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for(int i=0;i<nStartPos.length;i++) B[w~bW|K
 
{ p)NhV  
if(!fileSplitterFetch.bDownOver) WLqwntzk  
{ %{Ez0XwGCn  
breakWhile = false; S7vT=  
break;  df;-E  
} u2,V34b-  
} 
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if(breakWhile) l6IpyIex  
break; maW,YOyRN  

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~ x- R78'  
//count++;
;& ny< gQ  
//if(count>4) M[LjN  
// siteStop(); z
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} B/hL  
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System.err.println("文件下载结束！"); zcnp?
%  
} ^W+q!pYM9+  
catch(Exception e){e.printStackTrace ();} ="hh=x.5J  
} fS+Ga1CsH  
=QXLr+ y@  
bq{":[a  
//获得文件长度 %9Br  
public long getFileSize() E(N?.i-%$  
{ `&xo;Vnc  
int nFileLength = -1; vs}_1o  
try{ B
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URL url = new URL(siteInfoBean.getSSiteURL()); 2YI#J.6]H  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); r*CI6yP  
httpConnection.setRequestProperty("User-Agent","NetFox"); AdMA|!|:hc  
\}[{q  
jp?;8rS3  
int responseCode=httpConnection.getResponseCode(); *<Yn  
if(responseCode>=400) /<,LM8n  
{ @LZ'Qc }@  
processErrorCode(responseCode); OCIWQ/ P  
return -2; //-2 represent access is error Vf<VKP[9K  
} !.9pV.~  
}#va#Nb(,  
#-?C{$2I  
String sHeader; 0]%0wbY1  
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UZ#Yd|'PD  
for(int i=1;;i++) 0*0]RC5?  
{ p(dJf&D  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); *;b.x"  
//Utility.log(in.readLine()); z9OhY]PPF  
sHeader=httpConnection.getHeaderFieldKey(i); )bN|*Bw3  
if(sHeader!=null) ) inhPd  
{ ;T6{J[ h  
if(sHeader.equals("Content-Length")) U"\$k&  
{ )pELCk  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 6apK]PT  
break; `D)ay  
} ernZfd{H  
} ')ZxWYT O^  
else $=?1>zvF  
break; ".ay
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} Teq1VK3Hr  
} CFdR4vuEI  
catch(IOException e){e.printStackTrace ();} a![x^@nF  
catch(Exception e){e.printStackTrace ();} =xzDpn>f  
d67Q@')00  
]XX9.Xh=-  
Utility.log(nFileLength); 6~g`B<(?  
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return nFileLength; $qOV#,@  
} IoUQ~JviA  
6b&<5,=d:  
m]LR4V6k|  
//保存下载信息（文件指针位置） "o.V`Bj  
private void write_nPos() {@j0?s  
{ N0APX4j  
try{ . !gkJ  
output = new DataOutputStream(new FileOutputStream(tmpFile)); LS1r}cl  
output.writeInt(nStartPos.length); 5cLq6[uO  
for(int i=0;i<nStartPos.length;i++) /O@'XWW  
{ !J<}=G5  
// output.writeLong(nPos); {c5%.<O  
output.writeLong(fileSplitterFetch.nStartPos); m?LnO5Vs  
output.writeLong(fileSplitterFetch.nEndPos); `@.  
} 29eg.E  
output.close(); Z(g9rz']0  
} Fh  t$7V  
catch(IOException e){e.printStackTrace ();} Z#H] yG  
catch(Exception e){e.printStackTrace ();} q:2Vw`g'  
} 9v[cy`\  
cTpmklq  
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//读取保存的下载信息（文件指针位置） d:KUJ Y.  
private void read_nPos() .1F(-mLd  
{ xRum q  
try{ UG)J4ZX  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); zQY|=4NP  
int nCount = input.readInt(); N~I2~f  
nStartPos = new long[nCount]; Qn`$xY9mT  
nEndPos = new long[nCount]; iaShxoIV  
for(int i=0;i<nStartPos.length;i++) yL =*yC  
{ ]WZ_~8  
nStartPos = input.readLong(); Ml &Cr  
nEndPos = input.readLong(); #=6A[<qX  
} 8&?kr/_Vr  
input.close(); nsO!  
} ~3p :jEM.[  
catch(IOException e){e.printStackTrace ();} r8PXdNg  
catch(Exception e){e.printStackTrace ();} ;uw`6 KJ  
} wk @-O}W  
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private void processErrorCode(int nErrorCode) gcLwQ-  
{ MDETAd  
System.err.println("Error Code : " + nErrorCode); m e\S:  
} G)qNu}  
+<cvyg5U  
8NY$Iw  
//停止文件下载 9rhIDA(wc  
public void siteStop() m~KGB"  
{ w]n ,`r^  
bStop = true; %3v:c|r  
for(int i=0;i<nStartPos.length;i++) {P'TtlEp  
fileSplitterFetch.splitterStop(); tnx
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3&*_5<t\X  
} "YIrqk
 
} \;"$Z9W  
//负责部分文件的抓取 Bvbv~7g(  
**FileSplitterFetch.java i1ph{;C  
*/ &V.ps1  
package NetFox; F_8< tA6  
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import java.io.*; 5p9zl=mT  
import java.net.*; 8<cD+Jtj  
*eE&ptx1  
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public class FileSplitterFetch extends Thread { :]?y,e%xu,  
RRYm.dMIw  
`o7m)T')  
String sURL; //File URL 8<z]rLQw?%  
long nStartPos; //File Snippet Start Position }(}+I}&~  
long nEndPos; //File Snippet End Position 6U{&`8C  
int nThreadID; //Thread's ID IfyyA  
boolean bDownOver = false; //Downing is over <@;Y.76~  
boolean bStop = false; //Stop identical Rg/*)SK
j  
FileAccessI fileAccessI = null; //File Access interface :H}a/ x*ur  
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kbij Zj{  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 3hzI6otKS  
{ Q/e$Ttt4J  
this.sURL = sURL; 5)=XzO0  
this.nStartPos = nStart; Z4eu'.r-y~  
this.nEndPos = nEnd; hY5G=nbO*  
nThreadID = id; VUfV=&D-*g  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 3Q-i%7l  
} oBVYgv)  
aBV{Xr~#(  
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public void run() ,^dyS]!d$  
{ SoS GQ&k  
while(nStartPos < nEndPos && !bStop) $6
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{ n0o'ns  
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try{ WdXi  
URL url = new URL(sURL); C %l!"s^  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); y1DP`Ro  
httpConnection.setRequestProperty("User-Agent","NetFox"); f< A@D"m/  
String sProperty = "bytes="+nStartPos+"-"; /mELnJ^  
httpConnection.setRequestProperty("RANGE",sProperty); yFfa/d  
Utility.log(sProperty); fX)C8J^=G  
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InputStream input = httpConnection.getInputStream(); M[wd.\ %  
//logResponseHead(httpConnection); Q}G'=Q]Juz  
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byte[] b = new byte[1024]; .r~!d|
  
int nRead; .]_Ye.}  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) U1&pcwP  
{ ;F)gr  
nStartPos += fileAccessI.write(b,0,nRead); 'jv[Gcss3L  
//if(nThreadID == 1) sP1wO4M?{  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); n-q  
} \Y[  
$4yv)6G  
#&+0hS  
Utility.log("Thread " + nThreadID + " is over!"); 0>#or$:6E  
bDownOver = true; x Bn+-V  
//nPos = fileAccessI.write (b,0,nRead); Qz*!jwg  
} |RUx)&  
catch(Exception e){e.printStackTrace ();} u(ep$>[F#_  
} ]lj,GD)c  
} -eKi}e  
FI,>v`  
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//打印回应的头信息 E|u#W3-:  
public void logResponseHead(HttpURLConnection con) ~GL"s6C$`;  
{ $t' .  
for(int i=1;;i++) &V;^xMO!  
{ 8nOMyNpy~M  
String header=con.getHeaderFieldKey(i); N 3IF j  
if(header!=null) |%JJ S^)  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 5@3[t`n'  
Utility.log(header+" : "+con.getHeaderField(header)); #BQ7rF7CNE  
else +dWx?$n  
break; K\5'pp1  
} : `D[0  
} m&)5QX  
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_=RA-qZ"  
public void splitterStop() r&AX  
{ =
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bStop = true; o
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} M{Ss?G4H  
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} F,0@z/8a  
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/* tB
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**FileAccess.java ZKKz?reM'  
*//文件访问(定位，写) C`F*00M{  
package NetFox; fuM+{1}/E  
import java.io.*; MS{purD  
-^=sxi,V  
8D[8(5  
public class FileAccessI implements Serializable{ Jd_w:H.  
h>v;1QO9D  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 :O:Rfmr~  
RandomAccessFile oSavedFile; /s.O3x._'  
long nPos; 4^1B'>I  
@fR^":.h  
uPk`9c52%  
public FileAccessI() throws IOException XGE:ZVpW  
{ tqLn
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this("",0); @NMFurm  
} p"4i(CWGS  
k$</7IuH  
fI"q/+  
public FileAccessI(String sName,long nPos) throws IOException b#h?O}  
{ Uq/#\7/rL  
oSavedFile = new RandomAccessFile(sName,"rw"); !4uTi [e  
this.nPos = nPos; f(.@]eu X  
oSavedFile.seek(nPos); reml|!F-)  
} Sfc0 ~1  
wCiDvHF5+C  
srfFJX7*  
public synchronized int write(byte[] b,int nStart,int nLen) .5+*,+-  
{ ND[u$N+5x"  
int n = -1; m%ZJp7C  
try{ J_tj9+r^  
oSavedFile.write(b,nStart,nLen); D*+uH;ws  
n = nLen; "@!z+x[8  
} XHuY'\;-  
catch(IOException e) ]@OGp:Hz  
{ n*-t =DF  
e.printStackTrace (); T^h;T{H2  
} bX#IE[Yp}  
O/\L0\T  
$3BCA)5:  
return n; R }M'D15  
} =jvM$  
/sY(/ JE  
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} UF)rBAv(/  
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/* xq_%|p}y  
**SiteInfoBean.java hNB;29r~  
*/ .$b]rx7$~  
package NetFox; e*_8B2da  
lcgT9m#  
96;17h$  
public class SiteInfoBean { xQ4D| &  
Tj@}O:q7:  
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private String sSiteURL; //Site's URL !=C4=xv  
private String sFilePath; //Saved File's Path <)y44x|S'  
private String sFileName; //Saved File's Name (g,lDU[=  
private int nSplitter; //Count of Splited Downloading File Q\G8R^9j p  
Izq]nR  
"6/`  
public SiteInfoBean()
!}wJ+R ^2  
{//nSplitter的缺省值为5 0S@O]k)  
//default value of nSplitter is 5 d;&'uiS  
this("","","",5); g~_cYy  
} 24{!j[,q@  
f !t2a//  
F\!;
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) =W)Fa6P3j(  
{ hGi"=Oud2  
sSiteURL= sURL; MfUG@  
sFilePath = sPath; K[RlR+j  
sFileName = sName; xP3_  
this.nSplitter = nSpiltter; S/-[OA>N  
b Jt397  
!cnunLc`  
} RWmQP%A}aw  
8[(eV.  
E>Ukxi1  
public String getSSiteURL() )t={+^Xe  
{ KL]K< A  
return sSiteURL; jLC,<V*  
} P<GY"W+rR  
TF 6_4t6  
%Qc#v$;+J  
public void setSSiteURL(String value) KquHc-fzqr  
{ ^7v}wpwX\  
sSiteURL = value; "m +Eu|{  
} /b,+YyWi%  
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aNb=gjLpt  
public String getSFilePath() M= !Fb  
{ Mt)~:V+
:  
return sFilePath; 8'J>@ uW  
} #(3w6l2  

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rb%P30qc4  
public void setSFilePath(String value) 3:jKuOX  
{ A<^IG+Q,B7  
sFilePath = value; %Rv&VFg  
} BDZB;DPb  
eKn&`\j6  
%)*!(%\S*3  
public String getSFileName() b_-ESs]g  
{ +<6L>ZAL  
return sFileName; E&V"z^qs_  
} ~PaD _W#xP  
pI7\]e  
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public void setSFileName(String value) $s.:wc^  
{ _Hi;Y  
sFileName = value; '-3AWBWI1  
} !>b>"\b  
i`7{q~d=  
iaXNf ])?  
public int getNSplitter() XyJ*>;q  
{ leyhiL<  
return nSplitter; CJg &  
} }MY7<sMDOy  
#T Cz$_=t  
z=<T[Uy  
public void setNSplitter(int nCount) a#FkoA~M  
{ E+V^5Z:u  
nSplitter = nCount; rklr^ e  
} 3;~1rw=$<  
} 9Am&G  
4IG=mG)  
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/* W%b<(T;  
**Utility.java %1SA!1>j  
*/ aq~hl7MTj  
package NetFox; 8#'<SB  
hXM8`iFW5  
-h^FSW($-R  
public class Utility { )v;>6(  
('Wo#3b$  
)u]J`.OA  
public Utility() 4>>{}c!nf  
{ '|&}rLr:+  
w{)*'8oCB  
UBqA[9  
} hLGUkG?6G  
]B=B@UO@.  
//线程睡眠 <(`dU&&%"}  
public static void sleep(int nSecond) )5gcLD/zI  
{ |\@e  
try{ 6kGIO$xJ)  
Thread.sleep(nSecond); 5+rYk|*D+k  
} 5tHv'@  
catch(Exception e) 'IBs/9=ZC  
{ Dk|
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e.printStackTrace (); (~xFd^W9o  
} cy7GiB2'  
} Tk$rwTCl  
!I]fNTv
<  
//日志 W=}l=o!G.  
public static void log(String sMsg) f'F:U^  
{ 5p"n g8nR  
System.err.println(sMsg); xr?=gY3E;  
} 5 g99t$p9  
GZ/.eYE  
vmJ1-<G4*  
public static void log(int sMsg) ~6.AE/ow  
{ >Mj :'  
System.err.println(sMsg); En8-Hc#NC  
} qqT6C%Q`kG  
} hD{+V!{  
6[wej$u  
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/* (ZQ{%-i?qR  
**TestMethod.java kU_bLC?>D  
*/ E:xpma1Qf  
package NetFox; nf+8OH7  
}cgEC-  
)52:@=h*l  
public class TestMethod { )XMSQ ="m  
ps"crV-W  
cKh
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public TestMethod() f<9H#S:  
{ ///xx/weblogic60b2_win.exe Sd' uXX@  
try{ _7~O>
.  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); :-.R*W  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); |!8[Vg^Wh  
SiteFileFetch fileFetch = new SiteFileFetch(bean); jC ,f
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fileFetch.start(); wfM$JYfI  
} @!'Pr$`  
catch(Exception e){e.printStackTrace ();} N\=pH{  
5!}xl9D  
:y!e6  
} |4YDvDEJi  
:N\*;>  
!cE>L~cza  
public static void main(String[] args) kLR4?tX!  
{ @YdS_W  
new TestMethod(); .
a:"B\B`  
} \E9Z
H3;  
} r1EccY  
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