http断点续传简单实现（java)

/* ]hE+$sKd  
**SiteFileFetch.java T5Sg2a1&  
*/ Q"|kW[Sg  
package NetFox; bugFl>  
import java.io.*; P$18Xno{  
import java.net.*; ZSPgci  
W 9Vz[  
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public class SiteFileFetch extends Thread { yYToiW *  
n<?SZ^X{,/  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 5BHOHw D{  
long[] nStartPos; //开始位置 dGsS<@G  
long[] nEndPos; //结束位置 3G%wZ,)C  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 |'c4er/;#  
long nFileLength; //文件长度 ?Z Rkn+;  
boolean bFirst = true; //是否第一次取文件 e(~'pk"mZ  
boolean bStop = false; //停止标志 :YqQlr\
 
File tmpFile; //文件下载的临时信息 6!+X.+  
DataOutputStream output; //输出到文件的输出流 M_h8#7{G  
U.RW4df%E  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） VJN/#   
public SiteFileFetch(SiteInfoBean bean) throws IOException \ I^nx+l  
{ -4e)N*VVu  
siteInfoBean = bean; 9K;k%  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 4r1<,{gCS  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info");
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if(tmpFile.exists ()) N )zPxQ  
{ CYtjY~  
bFirst = false; | "Jx  
read_nPos(); j?\$G.Y  
} gT(th9'+z  
else JG@L5f  
{ "($Lx  
nStartPos = new long[bean.getNSplitter()]; 9jO`gWxV8*  
nEndPos = new long[bean.getNSplitter()]; &_9YLXtMi;  
} 'u(=eJ@1  
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} -,QKTxwo>  
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|5=~(-I>@  
public void run() nAo8uWG  
{ d"B@c;dD  
//获得文件长度 J}Qs"+x  
//分割文件 s~=KhP~  
//实例FileSplitterFetch qr)v'aC3  
//启动FileSplitterFetch线程 <.,RBo  
//等待子线程返回 L#`2.nU  
try{ EI1W .V>@  
if(bFirst) ]}z'X!v_@  
{ +65oC x  
nFileLength = getFileSize(); t_dcV%
=  
if(nFileLength == -1) ^IX%dzM  
{ n1QEu"~Zj  
System.err.println("File Length is not known!"); `d7gm;ykp  
} @B,j;2eb  
else if(nFileLength == -2) nJFk4v4:2  
{ .E+OmJwD  
System.err.println("File is not access!"); "jL1.9%"  
} u64@"P  
else #^|| ]g/N  
{ (n=9c%w  
for(int i=0;i<nStartPos.length;i++) m`hGDp3  
{ f).*NX  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); CO-Iar  
} /8xH$n&xoC  
for(int i=0;i<nEndPos.length-1;i++) N'I(P9@  
{ izMYVI?
0  
nEndPos = nStartPos[i+1]; [34zh="o  
} 1ZT^)/G  
nEndPos[nEndPos.length-1] = nFileLength; ,YjxCp3  
} u`'ki7LA  
} /~40rXH2C
 
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7\mDBG  
//启动子线程 JOBz{;:R{  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; r5o
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for(int i=0;i<nStartPos.length;i++) m_a^RB(  
{ -=>sTMWpr  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Hx$.9'Oq\Q  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), L-#e?Y}$J
 
nStartPos,nEndPos,i); (O$}(Tn  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); D=$4/D:;  
fileSplitterFetch.start(); }@d>,1DU  
} pe|X@o  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), N83!C=X'  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); l+%Fl=Q2em  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 4~!Eje!  
nEndPos = " + nFileLength); LU%#mY  
// fileSplitterFetch[nPos.length-1].start(); O?CdAnhQc`  
d]U`?A,  
YWEYHr;%^?  
//等待子线程结束 :-z&Y492  
//int count = 0; K[kds`  
//是否结束while循环 a$d:_,\"  
boolean breakWhile = false; d$pYo)8o({  
^f9>l;Lb  
8qn 9|  
while(!bStop) OY:u',T  
{ Us'Cs+5XcG  
write_nPos(); 4S tjj!ew  
Utility.sleep(500); 0; 7#ji  
breakWhile = true; Z a! gbt  
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6 jmrD  
for(int i=0;i<nStartPos.length;i++) yE#g5V&  
{ kd yAl,  
if(!fileSplitterFetch.bDownOver) Tr~sieL  
{ a0P
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breakWhile = false;
`M:DZNy,  
break; 42&v% ;R  
} <Z},A-\S*  
} J,??x0GDx,  
if(breakWhile) +p9- .YM  
break; I_ONbJ9]  
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}MP>]8Aq  
//count++; ]Ko^G_Rm  
//if(count>4) _BbvhWN&+  
// siteStop(); n+2%tW  
} vDsF-
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System.err.println("文件下载结束！"); =~&VdPZ  
} )>
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catch(Exception e){e.printStackTrace ();} ;+a2\j+  
} U9 #w  
=-w;zx  
"tUwo(K[  
//获得文件长度 hUh+JW  
public long getFileSize() eTT)P  
{ 5Tedo~v  
int nFileLength = -1; vwmBUix  
try{ ++b$E&lYU  
URL url = new URL(siteInfoBean.getSSiteURL()); |#k@U6`SG  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); h$>wv`
 
httpConnection.setRequestProperty("User-Agent","NetFox"); PQ$sOK|/  
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int responseCode=httpConnection.getResponseCode(); 1fH<VgF`  
if(responseCode>=400) sef]>q  
{ J? .F\`N)  
processErrorCode(responseCode); L_Q S0_1
 
return -2; //-2 represent access is error (!3;X"l  
} Hkege5{  
-}P7$|O&  
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String sHeader; 3@_Elu  
zyFUl%  
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for(int i=1;;i++) \9/RAY_G  
{ a7#?h%wf  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 1'JD=  
//Utility.log(in.readLine()); 0OnV0SIL  
sHeader=httpConnection.getHeaderFieldKey(i); vQ1 v#Z  
if(sHeader!=null) nn+_TMu  
{ u#@RM^738d  
if(sHeader.equals("Content-Length")) {e"dm5
 
{ (5a1P;_Y  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); rQb7?O@-  
break; ; b*i3*!g  
} Y%@hbUc}x9  
} eVJ^\z:4  
else GSi>l,y'  
break; $=)gpPT  
} #$E)b:xj  
} jo9gCP.  
catch(IOException e){e.printStackTrace ();} lyv4fP  
catch(Exception e){e.printStackTrace ();} O$D?A2eI  
;SY\U7B\  
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Utility.log(nFileLength); y t5H oy  
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return nFileLength; rS7)6h7(7  
} v-Qmx-N  
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//保存下载信息（文件指针位置） r@kP*  
private void write_nPos() |ZiC`Nt  
{ 'V (,.'  
try{ `\CVV*hP  
output = new DataOutputStream(new FileOutputStream(tmpFile)); esX)"_xf  
output.writeInt(nStartPos.length); jQ+sn/ROp  
for(int i=0;i<nStartPos.length;i++) fQdK]rLj  
{ 4<gb36)|4  
// output.writeLong(nPos); Mxl]"?z  
output.writeLong(fileSplitterFetch.nStartPos); G^;>8r  
output.writeLong(fileSplitterFetch.nEndPos); 5T?-zFMM  
} fuMJdAuY7d  
output.close(); 2VoKr)  
}
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catch(IOException e){e.printStackTrace ();} f0>!qt  
catch(Exception e){e.printStackTrace ();} ,r8Tbk]m  
} F(,UA+$A  
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;j%BK(5  
//读取保存的下载信息（文件指针位置） 2=iH
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private void read_nPos() C\*4q8(  
{ ,xfO;yd  
try{ B*
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DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); !mMpb/&&S  
int nCount = input.readInt(); bB}5U@G|  
nStartPos = new long[nCount]; `5~3G2T  
nEndPos = new long[nCount]; rsXq- Pq*  
for(int i=0;i<nStartPos.length;i++) p B;
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{ OI}cs2m  
nStartPos = input.readLong(); &(N+.T5cp  
nEndPos = input.readLong(); .@F]Pht  
} <RNJ>>0  
input.close(); T~:|!`  
} 4\M.6])_  
catch(IOException e){e.printStackTrace ();} EYX$pz(x;  
catch(Exception e){e.printStackTrace ();} $O)3q $|  
} p-SJ6Gg 9  
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alq%H}FF  
private void processErrorCode(int nErrorCode) vVl; |  
{ |r%D\EB  
System.err.println("Error Code : " + nErrorCode); OEx^3z^  
} hC <O`|lF  
cLVeT  
:'iYxhM.V  
//停止文件下载 OTDg5:>  
public void siteStop() H1n1-!%d  
{ NMOut@  
bStop = true; JM- t<.  
for(int i=0;i<nStartPos.length;i++) \>QF(J [8  
fileSplitterFetch.splitterStop(); {gbn/{  
7R!5,Js+  
UMl#D>:C<  
} NKb1LbnZ*y  
} \*f;Xaa  
//负责部分文件的抓取 e[_m<e  
**FileSplitterFetch.java qMt++*Ls  
*/ R:Q0=PzDi#  
package NetFox; L2Pujk  
uvP2Wgt  
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import java.io.*; Rp7ntI:  
import java.net.*; rE9I>|tX  
5NoI~X=  
/zDi9W*~1  
public class FileSplitterFetch extends Thread { }v:jncp  
%wcSM~w
 
:+Om]#`Vls  
String sURL; //File URL } :=Tm]S  
long nStartPos; //File Snippet Start Position `K~AhlJUQ  
long nEndPos; //File Snippet End Position 2_vbT!_  
int nThreadID; //Thread's ID B33$
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boolean bDownOver = false; //Downing is over ABE@n%|`  
boolean bStop = false; //Stop identical :
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FileAccessI fileAccessI = null; //File Access interface b2b?hA'k  
om?-WJI  
|sRipWh  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException )q7UxzE+  
{ m<FOu<y  
this.sURL = sURL; 8#!i[UFdj  
this.nStartPos = nStart; 5%sE]Y#  
this.nEndPos = nEnd; xk&Jl#
v  
nThreadID = id; {:@tQdM:i8  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 B#/Q'V  
} ;4N;D  
;q N+^;,2  
*HEuorl  
public void run() >D201&*G%  
{ ok|qyN+  
while(nStartPos < nEndPos && !bStop) V,rq0xW  
{ 3gd&i  
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-'~LjA(  
try{ b#7{{@H  
URL url = new URL(sURL); S26MDLk`R3  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ~/.7l8)  
httpConnection.setRequestProperty("User-Agent","NetFox"); Vz6Qxd{m3  
String sProperty = "bytes="+nStartPos+"-"; aaD;jxT&M|  
httpConnection.setRequestProperty("RANGE",sProperty); UG=K|OXWJ  
Utility.log(sProperty); "Ph^BUAb  
Sb~MQ_  
#>Zzf  
InputStream input = httpConnection.getInputStream(); `{qG1  
//logResponseHead(httpConnection); [JF150zr  
g=I8@m  
)iFJz/n>  
byte[] b = new byte[1024]; /cU<hApK  
int nRead; Um&(&?Xf  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) =s<( P1|"  
{ HRB<Y mP@  
nStartPos += fileAccessI.write(b,0,nRead); " Hd|7F'u=  
//if(nThreadID == 1) s%<e
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// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); [l
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} 3}e%[AKh  
ai0XL}!+  
&x3VCsC\|  
Utility.log("Thread " + nThreadID + " is over!"); w^t/9N
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bDownOver = true; :9k Ty:  
//nPos = fileAccessI.write (b,0,nRead); _a1x\,R|DB  
} O{#=d  
catch(Exception e){e.printStackTrace ();} s6>ZREf#J  
} =:~R=/ZXk  
} KEWTBBg  
5LOo8xN  
,cNLkoN  
//打印回应的头信息 KZ/=IP=  
public void logResponseHead(HttpURLConnection con) K'GBMnjD  
{ /~3r;M  
for(int i=1;;i++) H)n9O/u  
{ aA,!<^&}  
String header=con.getHeaderFieldKey(i); K.0:C`C  
if(header!=null) Hw4%uS==V  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); M3q|l7|9  
Utility.log(header+" : "+con.getHeaderField(header)); x)@G;nZ  
else w!D|]LoE  
break; 6fw(T.Pe  
} DY`kx2e!  
} kBffF@{  
d@qsdYu-*  
*6VF $/rP  
public void splitterStop() fZoHf\B]{  
{ jbAx;Xt'=M  
bStop = true; OynXkH]0T+  
} <[-nF"Q  
pS:4CNI{  
o,)?!{k}  
} ;5)P6S.D  
]?(-[  
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/* %rv7Jy   
**FileAccess.java t;}:waZD  
*//文件访问(定位，写) `7r@a  
package NetFox; yPal
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import java.io.*; 3qf Ym}d  
r[*Vqcz  
0.@&_XTPl  
public class FileAccessI implements Serializable{ "/wyZ  
h-[VH%  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 $6
9oV:  
RandomAccessFile oSavedFile; =o$sxb E(  
long nPos; y]f"@9G#  
2I,^YWR  
9J2NH|]c  
public FileAccessI() throws IOException W>j!Q^?  
{ M 
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this("",0); c_4[e5z  
} a m|F?|1  
JPoN&BTCj  
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public FileAccessI(String sName,long nPos) throws IOException ,Vt/(x-  
{ $}!p+$  
oSavedFile = new RandomAccessFile(sName,"rw"); vzim<;i  
this.nPos = nPos; E2Q[ZoVS  
oSavedFile.seek(nPos); !1$])VQWI  
} 4b98KsYg  
$\X[@E S0  
sT}.v*  
public synchronized int write(byte[] b,int nStart,int nLen) rustMs2p  
{ Z$/xy"  
int n = -1; o!kbK#k  
try{ CEX"D`  
oSavedFile.write(b,nStart,nLen); t.xxSU5~%  
n = nLen; AP'*Nh@Ik(  
} I|^;B8[  
catch(IOException e) B><d9d  
{ iKX-myCz  
e.printStackTrace (); ]&lY%"U$i  
} _./Sk|C  
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xc=b |:A  
return n; ^")Q YE  
} lh7
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} DH\0z[  
 : y%d  
g/CSGII
T  
/* S[PE$tYT#t  
**SiteInfoBean.java 0jy2H2  
*/ >0ow7Uw;  
package NetFox; VY |_dk  
t*Sa@$p  
I ?gSG*m  
public class SiteInfoBean { (nf~x  
Z2qW\E^_r  
/5(Yy}  
private String sSiteURL; //Site's URL %A1o.{H  
private String sFilePath; //Saved File's Path TO]@ Zu1  
private String sFileName; //Saved File's Name ~*z% e*EL  
private int nSplitter; //Count of Splited Downloading File RtTJ5@V(  
|$8~?7Jv  
c;Pe/d  
public SiteInfoBean() 7z JRJ*NB  
{//nSplitter的缺省值为5 ^c-  
//default value of nSplitter is 5 (l^3Z3zf&  
this("","","",5); ,,%i;  
} <m)$K  
D$ dfNiCH  
Xg|B \\  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) J:CXW%\ <q  
{ HK,cJahq  
sSiteURL= sURL; s4A43i'g!h  
sFilePath = sPath; *>7>g"  
sFileName = sName; m% -g~q  
this.nSplitter = nSpiltter; f
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7puFz4+f  
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} CZud& <  
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2@'oe7E  
public String getSSiteURL() v$7QIl_/7  
{ Mm.
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return sSiteURL; _aGOb;h  
} WA)yfo0A  
l?Udn0F  
vK|E>nL  
public void setSSiteURL(String value) 8@i7pBl@  
{ $WyD^|~SF  
sSiteURL = value; Qu?R8+"KS  
} %7zuQ \w  
_}lZ,L(w  
qE&v ;  
public String getSFilePath() YVQN&|-  
{ PRu 6xsyA  
return sFilePath; .7e2YI,S  
} JD)(oK%C  
<*16(!k0  
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public void setSFilePath(String value) [I'0,y  
{ nw-xSS{  
sFilePath = value; _<k\FU r  
} dgR g>)V  
{MtpkUN  
1C}NQ!.  
public String getSFileName() .k,1f*%  
{ RDW8]=uM  
return sFileName; ciBP7>'::  
} h`KFL/fT  
hn5h\M?  
Zn&, t &z  
public void setSFileName(String value) Sg&UagBj  
{ ^o^H3m  
sFileName = value; >80;8\  
} HW3 }uP\c  
)j9SGLo  
hL/)|N~  
public int getNSplitter() xSktg]u Se  
{ m+`fn;*  
return nSplitter; w~(1
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} .L9j>iP9 *  
7mI:|G  
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public void setNSplitter(int nCount) =5J7Hw&K  
{ e<3K;Q  
nSplitter = nCount;  aC$B2
  
} aZ2!i  
} RN$1bxY  
/1"(cQ%?  
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/* |jI#"LbF  
**Utility.java 3LAIl913  
*/ o<|cA5f\  
package NetFox; I8wXuIN_  
{@eJtF+2  
l)G^cSHF.3  
public class Utility { >p)MawT]  
l1T m`7}  
7E!IF>`  
public Utility() >6NRi/[  
{ $G8E 3|k  
S{]x  
SX<` {x&L  
} iP =V8g?L  
+MR.>"  
//线程睡眠 8$")%_1]  
public static void sleep(int nSecond) 9!6f-K  
{ j/R[<47  
try{ Ja,w
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Thread.sleep(nSecond); s3~lT.  
} &M46&^Jho  
catch(Exception e) pOGeruu?  
{ v=0(~<7B  
e.printStackTrace (); GR&z,  
} .:@Ykdm4I  
}
d ^^bke$~  
GGNvu)"  
//日志 BzkooJ  
public static void log(String sMsg) 8K.R=  
{ aoTM  
System.err.println(sMsg); dYT%  
} >pU$wq|i  
^Y=\#-Dd  
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public static void log(int sMsg) Wi*.TWz
3  
{ Gr7=:+0n|P  
System.err.println(sMsg); e5*ni/P  
} S]bmS6#  
} -K q5i  
\#f<!R4  
kjg~n9#T  
/* 48:>NW  
**TestMethod.java wLi4G@jJ  
*/ 3jGWkby0  
package NetFox; )k\H@Dy%$  
+1uF !G&l  
KV}FZ3jY  
public class TestMethod { qs
1 ?IYD  
4A8;tU$&  
G'oG</A  
public TestMethod() N/Z2hn/m  
{ ///xx/weblogic60b2_win.exe YUx.BZf7  
try{ 419x+3>}  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ]^Qn  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); !F1M(zFD  
SiteFileFetch fileFetch = new SiteFileFetch(bean); R@/"B8H  
fileFetch.start(); 5 xppKt  
} 6N",-c  
catch(Exception e){e.printStackTrace ();} 43|XSyS  
-7*ET3NSI/  
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} [Yo,*,y31  
brW :C?}  

3?c3<`TW  
public static void main(String[] args) ZX>AE3wk  
{ S4'  
new TestMethod(); T;L>;E>B  
} (MR_^t  
} zfc'=ODX  
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