http断点续传简单实现（java)

/* DTN@b!  
**SiteFileFetch.java BgD;"GD*W  
*/ b,7:=-D  
package NetFox; N{iBVl  
import java.io.*; p*W4^2(d  
import java.net.*; 5JDqSz{  
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public class SiteFileFetch extends Thread { _x z_D12  
}f^r@3Cb3  
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SiteInfoBean siteInfoBean = null; //文件信息Bean <!K2xb-d^  
long[] nStartPos; //开始位置 gPe*M =iF  
long[] nEndPos; //结束位置 0gHJ%m9s  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 w@.E}%bwq  
long nFileLength; //文件长度 A2Rr*e  
boolean bFirst = true; //是否第一次取文件 I'BoP  
boolean bStop = false; //停止标志 2j H`  
File tmpFile; //文件下载的临时信息 8;p6~&).C~  
DataOutputStream output; //输出到文件的输出流 uwQ{y>SG  
J7emoD[  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） O~9 %!LAu  
public SiteFileFetch(SiteInfoBean bean) throws IOException 6YrkS;_HS  
{ =9y'6|>l  
siteInfoBean = bean; ;%]
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//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); \Yz>=rY  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); =]\,I'  
if(tmpFile.exists ()) :cG_aOkid  
{ _+wou(1y  
bFirst = false; i5|A\Wv"  
read_nPos(); J^pL_  
} W$B>O  
else v%/_*69a  
{ ]&yO>\MgJB  
nStartPos = new long[bean.getNSplitter()]; Mmbb}(<  
nEndPos = new long[bean.getNSplitter()]; '\l(.N
 
} k5xzC&  
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} =iRc&  
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public void run() 0+;.T1?  
{ %D\TLY  
//获得文件长度 /Y:_qsO1  
//分割文件 el.;T*Wn  
//实例FileSplitterFetch B~lrd#qC  
//启动FileSplitterFetch线程 j3P)cz-0/L  
//等待子线程返回 er,R}v  
try{ h;^h[q1'  
if(bFirst) 9O?.0L  
{ /^DDU!=(<  
nFileLength = getFileSize(); Vg\EAs>f  
if(nFileLength == -1) M=x/PrY"R  
{ pJVzT,poh  
System.err.println("File Length is not known!"); ^;c!)0Q<Z  
} %@G<B  
else if(nFileLength == -2) *@dRL3c^=  
{ 6fY(u7m|p  
System.err.println("File is not access!"); hqFK2 lR  
} g*
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else %$Wt"~WE"O  
{ C z4"[C`;  
for(int i=0;i<nStartPos.length;i++) aQMET~A:  
{ IJs*zzR  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); I&YYw8&  
} !0fpD'f!n  
for(int i=0;i<nEndPos.length-1;i++) cA`R~o"  
{ W
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nEndPos = nStartPos[i+1]; 6WgGewn  
} /+"BU-aQk  
nEndPos[nEndPos.length-1] = nFileLength; >wdR4!x!?  
} ]b.@i&M  
} #|GP]`YT  
|Ag~k? QC  
E6NkuBQ((  
//启动子线程 MQD UJ^I$  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; >VE,/?71@  
for(int i=0;i<nStartPos.length;i++) #v=hiL  
{ ]"q)X{G(+  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Q68&CO(rE  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), @mNf(&  
nStartPos,nEndPos,i); /.aZXC$]  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); +AtZltM i  
fileSplitterFetch.start(); a_L&*%;  
} f&js,NU"  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), )2g\GRg6  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ^%)'wDK  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 6QLWF@  
nEndPos = " + nFileLength); <)uUAh  
// fileSplitterFetch[nPos.length-1].start(); hc"+6xc  
H"WkyvqXb  
]N:SB  
//等待子线程结束 &%>l9~F'~  
//int count = 0; 37v!:xF!  
//是否结束while循环 z=N'evx~  
boolean breakWhile = false; AVOzx00U  
{e<J}-/?  
(%oZgvM  
while(!bStop) *,%H1)Tj}  
{ 9 @!Og(l  
write_nPos(); d~D<;7M XJ  
Utility.sleep(500); z/.x
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breakWhile = true; 
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for(int i=0;i<nStartPos.length;i++) ?>1AT==wI  
{ go|/I&
  
if(!fileSplitterFetch.bDownOver) &[3 xpi{v  
{ y"]?TEd  
breakWhile = false; I+!w9o2nZ  
break; e/6WhFN#  
} @rRBo:0%  
} GLcf'$l  
if(breakWhile) d?oupW}uu  
break; 0 oEw1!cY  
y/$WjFj3"  
(W
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//count++; ]\v'1m"  
//if(count>4) TF}<,aR  
// siteStop(); `a["`N^  
} hWJ\dwF  
)xiic3F  
H\Y.l,^  
System.err.println("文件下载结束！"); AZ(["kh[  
} |<\o%89AM  
catch(Exception e){e.printStackTrace ();} ~x)Awdlu  
} QjWv?tm  
'aBX>M  
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//获得文件长度 3=o3VGZP  
public long getFileSize() Y1rU  
{ B0?E$8a  
int nFileLength = -1; |+~CdA  
try{ H~i+:X=I  
URL url = new URL(siteInfoBean.getSSiteURL()); 8v8?D8\=|  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); vd|P
THV_  
httpConnection.setRequestProperty("User-Agent","NetFox"); <T)9mJYr  
I+kGEHO}  
V()s!w  
int responseCode=httpConnection.getResponseCode(); L~"~C(g  
if(responseCode>=400) '\(Us^Ug  
{ SZpBbX$  
processErrorCode(responseCode); Pz,kSxe=  
return -2; //-2 represent access is error Uq<c+4)5  
} }y(1mzb  
o|>2X[T  
94=Wy-  
String sHeader; f>s3Q\+  
2oXsPrtZ  
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for(int i=1;;i++) r,(rWptf4  
{ T\:Vu{|  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); &{!FE`ZC_  
//Utility.log(in.readLine()); Y/2@P
zA|  
sHeader=httpConnection.getHeaderFieldKey(i); Wrf(
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if(sHeader!=null) KqG:o+V=  
{ WNrgqyM  
if(sHeader.equals("Content-Length")) XpJT
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{ b/:9^&z  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); v?,_SVgAi  
break; fJB
p,
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} yd$_XWp?\  
} a}|B[b  
else .}&bE1  
break; 'H`aQt+  
} hD/bgquT  
} Z*tB=  
catch(IOException e){e.printStackTrace ();} y))d[1E  
catch(Exception e){e.printStackTrace ();} !o+#T==p  
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Utility.log(nFileLength); ?x7zYE,6  
&W`."  
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return nFileLength; o9(:m   
} '`p#%I@  
_Jx.?8  
#f0J.)M  
//保存下载信息（文件指针位置） bX6eNk-L  
private void write_nPos() :aI[ lZ  
{ 1Jg&L~Ws"  
try{ }b)7gd=  
output = new DataOutputStream(new FileOutputStream(tmpFile)); vOy;=0$  
output.writeInt(nStartPos.length); ^#B`GV  
for(int i=0;i<nStartPos.length;i++) >B<jR$`6@  
{ W&#Ps6)8  
// output.writeLong(nPos); pUutI|mt/  
output.writeLong(fileSplitterFetch.nStartPos); =+%QfuK  
output.writeLong(fileSplitterFetch.nEndPos); &<2~7?$!  
} @W[`^jfQ  
output.close(); X31[  
} |=fa`8mG  
catch(IOException e){e.printStackTrace ();} 8fRk8  
catch(Exception e){e.printStackTrace ();} rJH u~/_Dq  
} u&z5)iU  
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//读取保存的下载信息（文件指针位置） Vr@I9W;D#  
private void read_nPos() piIj t  
{ pKJ0+mN#"  
try{ :c[iS~ ~Y  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); w/BaaF.0  
int nCount = input.readInt(); _^]2??V  
nStartPos = new long[nCount]; F6J,:  
nEndPos = new long[nCount]; %"B+;{y(5  
for(int i=0;i<nStartPos.length;i++) hC2@Gq  
{ m%hI@'  
nStartPos = input.readLong(); d#xi_L!  
nEndPos = input.readLong(); ]awu7}C9Z  
}  =z`#n}v  
input.close(); {_T?0L  
}
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catch(IOException e){e.printStackTrace ();} 6..G/,T
B  
catch(Exception e){e.printStackTrace ();} 0aj4.H*%  
} =$xxkc.~G  
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(Qq;ySZ#  
private void processErrorCode(int nErrorCode) %ub\+~  
{ x8
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System.err.println("Error Code : " + nErrorCode); @c,Qj$\1  
} 8-]\C  
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'qel3Fs"  
//停止文件下载 )RV.N}NU  
public void siteStop() 7.U CX"  
{ 50h?#u6?  
bStop = true; Mtxn@m{i;"  
for(int i=0;i<nStartPos.length;i++) }8tD|t[  
fileSplitterFetch.splitterStop(); ;U$Fz~rJ  
|rW,:&;  
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} xh|NmZg  
} _voU^-  
//负责部分文件的抓取 $0+n0*fp  
**FileSplitterFetch.java 1?+%*uoPX  
*/ Q#!|h:K  
package NetFox; **p|g<wvY*  
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%Y!31oC#  
import java.io.*; |hGi8  
import java.net.*; 4:m/w!q$  
.YOC|\  
t
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public class FileSplitterFetch extends Thread { /A$mP)}tz  
Eci,];S7  
+'aG&^k4  
String sURL; //File URL (b!`klQ  
long nStartPos; //File Snippet Start Position U&x)Q  
long nEndPos; //File Snippet End Position 5}-e9U  
int nThreadID; //Thread's ID !| ObNS  
boolean bDownOver = false; //Downing is over q8 jI y@  
boolean bStop = false; //Stop identical Igb@aGA  
FileAccessI fileAccessI = null; //File Access interface wP-BaB$_  
Y243mq-  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException R/5@*mv{  
{ P:Nj;Cxh  
this.sURL = sURL; Vm6 0aXm_  
this.nStartPos = nStart; R|tf}~u !x  
this.nEndPos = nEnd; ZDffR:An  
nThreadID = id; Km/#\$|}  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 nG Bjxhl  
} tUzef  
[OTZ"XQLI  
H!6nIS9yxt  
public void run() V'n4iM  
{ ZP*(ZU@j=Z  
while(nStartPos < nEndPos && !bStop) PO1|l-v<Yq  
{ )o51QgPy  
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try{ N5]}m:"pk  
URL url = new URL(sURL); 'UW]~  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); JY6&CL`C  
httpConnection.setRequestProperty("User-Agent","NetFox"); *(c><N  
String sProperty = "bytes="+nStartPos+"-"; Cx,)$!1  
httpConnection.setRequestProperty("RANGE",sProperty); dJ/(u&N  
Utility.log(sProperty); w]-,X`  
$)(K7> P  
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InputStream input = httpConnection.getInputStream(); ?U^h:n  
//logResponseHead(httpConnection); fwWE`BB  
j)A$%xUo  
vJ`'x  
byte[] b = new byte[1024]; b!do7%]i  
int nRead; s"jNS1B  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) T][r'jWQ  
{ cx_.+R  
nStartPos += fileAccessI.write(b,0,nRead); aNcuT,=(?8  
//if(nThreadID == 1) estDW1i)  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Qx{[#[Da  
} uW@o,S0:  
w26x)(7  
v8PH(d2{@  
Utility.log("Thread " + nThreadID + " is over!"); ~4MUac^w  
bDownOver = true; E]opA$JQ  
//nPos = fileAccessI.write (b,0,nRead); ;8VvpO^G/  
} zLeId83>  
catch(Exception e){e.printStackTrace ();} (K"8kQLY  
} =5zx]N1r  
} 6X1_NbC  
d|~A>YZ  
k~P{Rm;F  
//打印回应的头信息 ~C;1}P%9x  
public void logResponseHead(HttpURLConnection con) %b)~K|NEFf  
{ }3rWmo8V  
for(int i=1;;i++) orU++,S4Pm  
{ \Gzo^w  
String header=con.getHeaderFieldKey(i); Gb?O-z%8*  
if(header!=null) $IdY(f:.:5  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); wlY6h4c  
Utility.log(header+" : "+con.getHeaderField(header)); E\ 'X|/$a  
else ab5uZ0@  
break; _jhdqON6E  
} Vv]81y15Q;  
} q%^vx%aL\  
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`U~Y{f_!H  
public void splitterStop() +ISXyGu  
{ Xy;!Q`h(  
bStop = true; X*cf|g  
} G0u3*.  
5[1#d\QR  
JW`Kh*,~<  
} 4Pm
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>Za66<:  
/* |B0.*te6  
**FileAccess.java e>oE{_e  
*//文件访问(定位，写) fK$N|r  
package NetFox; _:tclBc8R  
import java.io.*; c=-2c&=&  
q|8p4X}/]  
[xVE0l*\  
public class FileAccessI implements Serializable{  ;7F|g  
H$ sNp\[{  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 4]\t6,Cz8  
RandomAccessFile oSavedFile; 9hG+?   
long nPos; YBX7WZCR  
i"rrM1/r  
!`VO#_TJ  
public FileAccessI() throws IOException &M,"%w!  
{ BBg&ZIYEh  
this("",0); ItoSORVV  
} HxVQeyOR  
})l+-H"  
=&-hU|ur  
public FileAccessI(String sName,long nPos) throws IOException [SW@"C!  
{ ,u,]ab  
oSavedFile = new RandomAccessFile(sName,"rw"); $LPu_FJ  
this.nPos = nPos; MI!JZI$z5  
oSavedFile.seek(nPos); FZ)Y<r8|s  
} 7{vnhl(Z  
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Q&rf&8iH  
public synchronized int write(byte[] b,int nStart,int nLen) J)l]<##  
{ `P`nqn  
int n = -1; VH{SE7  
try{ y %k`  
oSavedFile.write(b,nStart,nLen); '(/ZJ88JP  
n = nLen; ,H3C\.%w\  
} GQ-owH]  
catch(IOException e) \bh3&Z'.  
{ u&=SZX&G k  
e.printStackTrace (); ,{C(<1  
} GXEOgf#i  
/WDz;,X  
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return n; r: _-Cj  
} cVZCBcKC?  
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3q:-98DT  
} ifu"e_^  
l|-TGjsX  
X7sWu{n  
/* tPS.r.0#^  
**SiteInfoBean.java ksxacRA7\  
*/ `p&ko$i2  
package NetFox; >#@1 I  
-(n[^48K  
|Hbe]2"x>  
public class SiteInfoBean { cJ&e^$:Er  
Ii?"`d+JA  
.P=uR8  
private String sSiteURL; //Site's URL 9?*BN
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private String sFilePath; //Saved File's Path 'aB0abr|  
private String sFileName; //Saved File's Name o} #nf$v(  
private int nSplitter; //Count of Splited Downloading File 9Byk/&$U  
Z`xz|:D+  
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public SiteInfoBean() dXh@E7
 
{//nSplitter的缺省值为5 1Tn!.E *  
//default value of nSplitter is 5
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this("","","",5); 3zb;q@JV  
} y+RT[*bX5o  
VI%879Z\e  
/Q"nQSG  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) M* W=v  
{ p[e|N;W8A  
sSiteURL= sURL; +w/Ax[K  
sFilePath = sPath; Ep}KIBBO  
sFileName = sName; O.=~/!(  
this.nSplitter = nSpiltter; {6<7M  
)o[ O%b  
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} >taS<.G  
pBt/vSad  
\n850PS  
public String getSSiteURL() @A6\v+ih  
{ (Jfi 3 m  
return sSiteURL; v&(X&q  
} 2 G_*Pqc  
a#1LGH7E8  
qH6DZ|  
public void setSSiteURL(String value) QEM")(  
{ 9AJ!7J#v"  
sSiteURL = value; gFJ&t^yL  
} -e%=Mpq.  
fH
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t4?g_$>   
public String getSFilePath() lN+NhPF  
{ i^uC4S~  
return sFilePath;  zUqiz  
} )dLESk  
i{VjSWq  
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public void setSFilePath(String value) @( 9#\%=  
{ #hd<5+$U}l  
sFilePath = value; JBE'B Q@  
} /,5`#Gte_  
>w9)c|  
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public String getSFileName() |Xd[%W)  
{ z$-/yT"M  
return sFileName; ,I=ClmR  
} $X9Ban]  
(k M\R|  
vD) LRO Z  
public void setSFileName(String value) v%&f00  
{ C3 0b}2  
sFileName = value; iTD}gC  
} P1 (8foZA  
> Q@*o  
(eJr-xZ/  
public int getNSplitter() $t1]w]}d  
{ SlZL%
C;  
return nSplitter; `+B+RQl}[  
} 9;Wz;p  
qB]z"Hfq,  
dWD,iO_"@  
public void setNSplitter(int nCount) h1K 3A5  
{ ACl:~7;  
nSplitter = nCount; \\hZlCV,  
} M)EKS  
} =Mn!
[  
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/* R_vZh|  
**Utility.java )0AE*S  
*/ 'QT(TF>  
package NetFox; =JO|m5z8>  
4g\a$7r  
]vQo^nOo  
public class Utility { PBn(k>=+  
92Ar0j]  
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public Utility() 8)"KPr63M  
{ YhLtf(r  
6{lWUr  
o;];ng  
} (^a;2j9  
L{^DZg|E  
//线程睡眠 pJa FPO..|  
public static void sleep(int nSecond) &%qD Som3  
{ )r?i^D&4  
try{ \
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Thread.sleep(nSecond); 4N$svA  
} .[2MPjg  
catch(Exception e) f[.hN  
{ W]
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e.printStackTrace (); s7xRry  
} ~g|e?$j  
} ;S?1E
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K/\#FJno  
//日志 $Q{1^  
public static void log(String sMsg) :R_{tQ-WG  
{ 6-KC[J^Xo  
System.err.println(sMsg); ~O1*]  
} N8D'<BUC  
:WA o{|&  
{tR=D_5  
public static void log(int sMsg) @%\ANM$S  
{ +o'. !sRH  
System.err.println(sMsg); _hh|/4(  
} xo@N~
 
} %m+MEh"b5  
m\Tq0cT$  
$d8A_CUU  
/* -'}
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**TestMethod.java /WHhwMc!  
*/ pHg8(ru|  
package NetFox; lh#GD"^(w&  

wkJB5i^<w  
GV[%P  
public class TestMethod { _L$)~},cT  
=r-Wy.a@  
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9
 
public TestMethod() TJ;v}HSo  
{ ///xx/weblogic60b2_win.exe =dA T^e##  
try{ (ZEVbAY?i  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); |%RFXkHS  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); U1q$B32  
SiteFileFetch fileFetch = new SiteFileFetch(bean); +:'Po.{"  
fileFetch.start(); nr-
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} )<^ ~${$U  
catch(Exception e){e.printStackTrace ();} ok6e=c '  
:T{or-  
8dA
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} $s]@%6f  
iMA)(ZS  
%BG5[XQ7  
public static void main(String[] args) xrX("ili  
{ O4E2)N  
new TestMethod(); |@ldXuYb  
} w5*18L=O\  
} ^U`q1Pg5  
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