http断点续传简单实现（java)

/* jasy<IqT!{  
**SiteFileFetch.java 1?+St`+{B-  
*/ M@v.c;Lt  
package NetFox; Ne1$ee.NE  
import java.io.*; Si;H0uPO  
import java.net.*; MeZf*' J  
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public class SiteFileFetch extends Thread { n<R?ffy  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 59;KQ  
long[] nStartPos; //开始位置 wgGl[_)  
long[] nEndPos; //结束位置 ^WWQI+pk  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 &7tbI5na@  
long nFileLength; //文件长度 \bvfEP  
boolean bFirst = true; //是否第一次取文件 &E5g3lf  
boolean bStop = false; //停止标志 t&e{_|i#+  
File tmpFile; //文件下载的临时信息 }a(dyr`S  
DataOutputStream output; //输出到文件的输出流 <bEbweQrgm  
m GYoM  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） k!'a,R:  
public SiteFileFetch(SiteInfoBean bean) throws IOException ,/|T-Ka
 
{ m#\dSl}  
siteInfoBean = bean; {V CWn95Z  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); )irEM  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 'YSHi\z ](  
if(tmpFile.exists ()) z9Rp`z&`E  
{ 3eQ&F~S  
bFirst = false; `*1p0~cu  
read_nPos(); p>8D;#HmL  
} 0{-q#/  
else NyNXP_8  
{ ' %o#q6O  
nStartPos = new long[bean.getNSplitter()]; WX3-\Y5E  
nEndPos = new long[bean.getNSplitter()]; "87:?v[[1  
} =fFP5e ['  
sdw(R#GE  
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} BR;D@R``}  
t'k$&l}+  
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public void run() XUuN )i  
{ $*=<Yw
4  
//获得文件长度 bY~pc\V:`w  
//分割文件 'E""amIJ  
//实例FileSplitterFetch oe-\ozJ0  
//启动FileSplitterFetch线程 0oIe>r  
//等待子线程返回 4 "'~NvO  
try{ 9InVQCf2J  
if(bFirst) 4^|3Tn
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{ svH !1b  
nFileLength = getFileSize(); q^<?]8  
if(nFileLength == -1) 1#+S+g@#  
{ YS"=yye3e  
System.err.println("File Length is not known!"); P71Lqy)5}A  
} "S?z@i(K^  
else if(nFileLength == -2) W
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{ z!9-
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System.err.println("File is not access!"); E+;7>ja  
} </*6wpN  
else h2fNuu"  
{ }:)&u|d_  
for(int i=0;i<nStartPos.length;i++) #?:lb1  
{ gc$l^`+M  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); O3kA;[f;  
} hM@>q&q_  
for(int i=0;i<nEndPos.length-1;i++) X45%e!  
{ `3&v6  
nEndPos = nStartPos[i+1]; rmg}N  
} 7J<5f)  
nEndPos[nEndPos.length-1] = nFileLength; QhJiB%M
 
} 8v%o,"  
} &^Q/,H~S  
c\AfaK^KF  
;u)I\3`*!  
//启动子线程 $*fMR,~t&  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; SO0PF|{\r  
for(int i=0;i<nStartPos.length;i++) ;uP:"k  
{ 20Wg=p9L  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), sd|).;s}  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 1p=]hC  
nStartPos,nEndPos,i); qY!Zt_Be6  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); HN|%9{VeB  
fileSplitterFetch.start();
& >fQp(f  
} 11;MN  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), #AQV(;r7@  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); /IMFO:c  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 0n{=%Q  
nEndPos = " + nFileLength); h~zT ydnH  
// fileSplitterFetch[nPos.length-1].start(); Ig>(m49d  
Er?&Y,o  
r_A$DaC]  
//等待子线程结束 vx5Zl&6r  
//int count = 0; TOQP'/   
//是否结束while循环 c{w2Gt!  
boolean breakWhile = false; qlP
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<wD-qTW  
[/8%3  
while(!bStop) '^UI,"Ti  
{ )lDD\J7  
write_nPos(); IjnU?Bf  
Utility.sleep(500); 'TB2:W3
 
breakWhile = true; _X x/(.O  
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for(int i=0;i<nStartPos.length;i++) `VguQl_,gA  
{ b4N[)%@  
if(!fileSplitterFetch.bDownOver) 7B66]3v  
{ #o#H?Vo9b  
breakWhile = false; a9V,es"BWQ  
break;
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} X#
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} Slc\&Eb  
if(breakWhile) om:VFs\U  
break; "VMz]ybi^  
nAlQ7'  

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//count++; bV3|6]k^  
//if(count>4) KoT%Mfu  
// siteStop(); FfT

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} Wmv#:U  
SXP]%{@R/  
f]srRYSR  
System.err.println("文件下载结束！"); Uw<nxD/+  
} U|R_OLWAg  
catch(Exception e){e.printStackTrace ();} S{T >}'y  
} 8Z=R)asGS  
|M;7>'YNC*  
=[7Av>  
//获得文件长度 8zW2zkv2|#  
public long getFileSize() +9sQZB# (  
{ <lJ345Q  
int nFileLength = -1; l9Q-iJ  
try{ ~})e?q;b  
URL url = new URL(siteInfoBean.getSSiteURL()); (X*^dO  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 1T n}
 
httpConnection.setRequestProperty("User-Agent","NetFox"); ?(_08O  
'PW5ux@`<  
")p\q:z6  
int responseCode=httpConnection.getResponseCode(); Z6MO^_m2  
if(responseCode>=400) *MW\^PR?  
{ 44j*KsBf  
processErrorCode(responseCode); SiN0OB  
return -2; //-2 represent access is error ]u/sphPe  
} )MT}+ai  
tw)mepwB  
^E>3|du]O  
String sHeader; -X6PRE5a2  
5~DJWi,  
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for(int i=1;;i++) uHRsFlw  
{ !&@615Vtw  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); /Z}}(6T  
//Utility.log(in.readLine()); +D*Z_Yh6  
sHeader=httpConnection.getHeaderFieldKey(i); >9Vn.S  
if(sHeader!=null) }4X0epPp;:  
{ ]7c=PC  
if(sHeader.equals("Content-Length")) R`-S/C  
{ MVUJD{X#  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); zX i'kB  
break; A?OQE9'  
} &_8947  
} |-~Y#
]  
else Pr C{'XDlU  
break; a(ZcmYzXU  
} |CbikE}kL  
} @BMx!r5kn  
catch(IOException e){e.printStackTrace ();} lq7E4r  
catch(Exception e){e.printStackTrace ();} :7;@ZEe  
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Utility.log(nFileLength); VuZr:-K/  
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0JujesUw(  
return nFileLength; Zx>=t
x}  
} \o3gKoL%  
S$-7SEkO+  
ba9?(+i$h  
//保存下载信息（文件指针位置） ?:9"X$XR  
private void write_nPos() 8
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{ *|HY>U.  
try{ )0k53-h&  
output = new DataOutputStream(new FileOutputStream(tmpFile)); <IW$m!{VG  
output.writeInt(nStartPos.length); [()koU#w.  
for(int i=0;i<nStartPos.length;i++) <(!:$  
{ ql~J8G9  
// output.writeLong(nPos); b%c9oR's^  
output.writeLong(fileSplitterFetch.nStartPos); f* wx<  
output.writeLong(fileSplitterFetch.nEndPos); :[d9tm  
} MLp9y#  
output.close(); `">=  
} V0Hj8}l;M  
catch(IOException e){e.printStackTrace ();} &BSn?  
catch(Exception e){e.printStackTrace ();} RT8 ?7xFc  
} ,<X9Y2B  
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//读取保存的下载信息（文件指针位置） "$vRM
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private void read_nPos() 0<*<$U  
{ Vi|#@tC'  
try{ ?Z}
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DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); EKN~H$.  
int nCount = input.readInt(); j5h-dK  
nStartPos = new long[nCount]; uHNCSzH(  
nEndPos = new long[nCount]; #[[ en  
for(int i=0;i<nStartPos.length;i++) tO&^>&;5  
{ N6TH}~62}  
nStartPos = input.readLong(); 86H+h(R/  
nEndPos = input.readLong(); |5]X| v
 
} cidP|ie^  
input.close(); f%8C!W]Dm  
} "ocyK}l.?  
catch(IOException e){e.printStackTrace ();} 8RHUeRX  
catch(Exception e){e.printStackTrace ();} "9807OME  
} D)}v@je"yP  
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private void processErrorCode(int nErrorCode) -tU'yKhn  
{ Rk8P ax/JK  
System.err.println("Error Code : " + nErrorCode); NX&_p!_V  
} dQG=G%W  
\ 6MCxh6  
f?)-}\[IR{  
//停止文件下载 @E8+C8'  
public void siteStop() HE\K@3-  
{ [_:nHZb  
bStop = true; $Ygue5{c  
for(int i=0;i<nStartPos.length;i++) A?0Nm{O;3v  
fileSplitterFetch.splitterStop(); 2+WaA,   
CU~PT.  
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} c4zR*  
} 3r1*m  +  
//负责部分文件的抓取 ,tRj4mx  
**FileSplitterFetch.java fd9k?,zM  
*/ $NO&YLS@  
package NetFox; T6kdS]4-  
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import java.io.*; ^/k*h J{  
import java.net.*; >5 BJ
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public class FileSplitterFetch extends Thread { m)D|l1AtF  
|+"(L#wk  
]{>,rK[So  
String sURL; //File URL {Hk}Kow  
long nStartPos; //File Snippet Start Position <\S:'g"(  
long nEndPos; //File Snippet End Position W!(LF7_!  
int nThreadID; //Thread's ID k|f4Cf,  
boolean bDownOver = false; //Downing is over %N_%J
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boolean bStop = false; //Stop identical {fp[BF  
FileAccessI fileAccessI = null; //File Access interface |gY
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8a"%0d#  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Vf1^4t  
{ Dum9l
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this.sURL = sURL; k==h|\|  
this.nStartPos = nStart; |vzl. ^"-  
this.nEndPos = nEnd;
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nThreadID = id; v(%*b,^  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 -H-~;EzU  
} rU(+T0t?I  
0Y5_PTWb+Y  
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public void run() BfiD9ka-z  
{ ~7Ux@Sx;  
while(nStartPos < nEndPos && !bStop) Ssg&QI  
{ YZJyk:H\  
9-m=*|p  
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try{ ^LzF@{ G  
URL url = new URL(sURL); _h1mF<\ X^  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 7Fsay+a  
httpConnection.setRequestProperty("User-Agent","NetFox"); _GPl gp:  
String sProperty = "bytes="+nStartPos+"-"; kg\>
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httpConnection.setRequestProperty("RANGE",sProperty); J9S>yLQK  
Utility.log(sProperty); 6D_D';o  
}W,[/)M
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UkGCyGyZ[  
InputStream input = httpConnection.getInputStream(); {BU
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//logResponseHead(httpConnection); B#1;r-^P<  
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byte[] b = new byte[1024]; `~q<N  
int nRead; r9G>jiw8  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) L9#g)tf 8T  
{ jZrq{Z<  
nStartPos += fileAccessI.write(b,0,nRead); ~WV"SaA)*U  
//if(nThreadID == 1) &PtJ$0%q  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); JOBhx)E  
} [z9Z5sLO  
'@P^0+B!(.  
KJZ4AWH`  
Utility.log("Thread " + nThreadID + " is over!"); b5n'=doR/I  
bDownOver = true; lsNd_7k  
//nPos = fileAccessI.write (b,0,nRead); -d:Jta!}{  
} kylVH! @l  
catch(Exception e){e.printStackTrace ();} 8DaL,bi*.  
} ^sWT:BDh  
} o2\8OxcA  
R@rBEW&
 
d m%8K6|  
//打印回应的头信息 ;i:d+!3XwC  
public void logResponseHead(HttpURLConnection con) QkC(uS  
{ U~7c+}:c  
for(int i=1;;i++) ufT`"i  
{
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String header=con.getHeaderFieldKey(i); '1/i"yoW  
if(header!=null) |$_sX9\`?|  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); @U
}1EC{A  
Utility.log(header+" : "+con.getHeaderField(header)); H} g{Cr"Ex  
else @D
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break; ;sFF+^~L  
} VVOd]2{  
} 3sZ\0P}   
,s;UfF  
.#pU=v#/[  
public void splitterStop() G,w(d@  
{ $* Kvc$D  
bStop = true; wLr_-vJ  
} wq`Bd  
}RqK84K  
>[*qf9$  
} *c+
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*~i ])4  
/* /&94 eC  
**FileAccess.java ,zY$8y
]  
*//文件访问(定位，写) 'uEl~> l7  
package NetFox; 2jhxQL  
import java.io.*; 1|wL\I  
f& '  
VP]%Hni]  
public class FileAccessI implements Serializable{ I~XSn>-H  
S{m%H{A!  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 A^<iL  
RandomAccessFile oSavedFile; PwLZkr@4^  
long nPos; -3Vx76Y  
d6 5L!4  
'!$Rw"K.  
public FileAccessI() throws IOException c!9nnTap  
{ V "h +L7T  
this("",0); @;RXLq/8  
} u.Dz~$T  
CeC6hGR5  
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public FileAccessI(String sName,long nPos) throws IOException vRO _Q?  
{ wAW5 Z0D  
oSavedFile = new RandomAccessFile(sName,"rw"); @<&m|qtMsz  
this.nPos = nPos; d/DB nZN  
oSavedFile.seek(nPos); o`*,|Nsq  
} D}X\Ca"h  
8-77d^cprR  
'Qe;vZ31K  
public synchronized int write(byte[] b,int nStart,int nLen) kPLxEwl  
{ W6/yn
 
int n = -1; :6\qpex  
try{ ]?[fsdAQW  
oSavedFile.write(b,nStart,nLen); e^D]EA]%  
n = nLen; FJP-y5  
} ~R92cH>L  
catch(IOException e) 0:Ol7  
{ 3'
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e.printStackTrace (); [u*5z.^  
} 6,{$J  
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return n; QMbOuw  
} (JFWna0@  
,nDaqQ-C!!  
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} YcpoL@ab  
rh}J3S5vp  
gSQJJxZ{?  
/* @6T/Tdz  
**SiteInfoBean.java g7W"  
*/ |8tilOqI  
package NetFox; I&W
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FQ5U$x.[P  
wDe& 1(T^  
public class SiteInfoBean { A2jUmK.&  
f=K]XTw~  
:&9s,l  
private String sSiteURL; //Site's URL DlMW(4(  
private String sFilePath; //Saved File's Path 81 sG  
private String sFileName; //Saved File's Name x+@rg];m  
private int nSplitter; //Count of Splited Downloading File @t_=Yl2
;  
'AH0ww_)n  
DN57p!z
 
public SiteInfoBean() o
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{//nSplitter的缺省值为5 &FN.:_E  
//default value of nSplitter is 5 ckE-",G  
this("","","",5); 2a Q[zK  
} ?+}_1x`  
'AS|ZRr/  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) O[JL+g4  
{ ZX./P0  
sSiteURL= sURL; %/#NK1&M  
sFilePath = sPath; {[?(9u7R  
sFileName = sName; 1NA.nw.  
this.nSplitter = nSpiltter; J]pir4&j  
N U
`  
6gu!bu`~  
} CdjI`  
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public String getSSiteURL() A*547=M/(j  
{ $C$V%5aA  
return sSiteURL; [j/9neaye  
} N~zdWnSZ@G  
#fn)k1  
aE$[52  
public void setSSiteURL(String value) K/yxE|w<  
{ Uf;^%*P4  
sSiteURL = value; R|87%&6']
 
} K} X&AJ5A  
&powy7rR  
|[aiJR[Q  
public String getSFilePath() :emiQ  
{ Sw,+p  
return sFilePath; Ig0VW)@  
} O.M>+~Nw  
,uhb~N<  
EaY?aAuS:  
public void setSFilePath(String value) ra gXn  
{ ^'{Fh"5  
sFilePath = value; ]Wlco
 
} p}pjfG  
eF-."1  
!9VY|&fHe  
public String getSFileName() -3Z,EaG^  
{ "CQa.%  
return sFileName; =wV<hg)C  
} m'=Crei  
e)? .r9pA;  
a![{M<Y~  
public void setSFileName(String value) IDriGZZ<)6  
{ h_,i&d@(  
sFileName = value; j@3Q;F0ba  
} q\4Xs$APq  
9W1YW9rL  
DgQpHF  
public int getNSplitter() +.b,AqJ/  
{ .2Elr(&*h  
return nSplitter; b&N'C9/8  
} 9x9T<cx  
u(F_oZ~  
9ZsVy
 
public void setNSplitter(int nCount) w4{<n/"  
{ U,{eHe ?>T  
nSplitter = nCount; %axh`xK#  
} U}rU~3N  
} \aUC(K~o\;  
V1`o%;j  
w(3G&11N?  
/* K+K#+RBK  
**Utility.java (Y?gn)*t  
*/ &>W$6>@  
package NetFox; j[G  
$2M$?4S/T  
Y0dEH^I  
public class Utility { x,@B(9No  
Zbt.t]N  
'9Xu p  
public Utility() Eib5  
{ /cQueUME`  
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rCbDu&k]  
} -[9JJ/7y  
1POmP&fI(  
//线程睡眠 }"P|`"WW  
public static void sleep(int nSecond) b)5uf'?-  
{ Ru!iR#s)!  
try{ H0gbSd+  
Thread.sleep(nSecond); 7p16Hv7y~  
} IT7
wT+  
catch(Exception e) J~zUp(>K  
{ */^q{PsN  
e.printStackTrace (); ;dtA4:IRZ4  
} %XoiVl
T@:  
} {{D)YldtA  
*-=(Q`3  
//日志 mt+Oi70  
public static void log(String sMsg) 7yH"l9Z  
{ }1c|gQ  
System.err.println(sMsg); PI:4m%[  
} 17[3/m8a  
p6]1w]*R  
4I k{  
public static void log(int sMsg) )@l%  
{ BB!THj69a6  
System.err.println(sMsg); j<99FW"@e  
} fo#fg8zX%  
} BxWPC#5  
HU8900k+  
n,V[eW#m'L  
/* c"n\cNP<  
**TestMethod.java d *|Y o  
*/ 2W96Zju\  
package NetFox; HV!m8k=6  
JPc+rfF  
$%CF8\0  
public class TestMethod { sV{,S>s  
Sw8]EH6  
+mmSfuO&\  
public TestMethod() 3G)#5Lf<  
{ ///xx/weblogic60b2_win.exe 7uS~MW  
try{ ?GoR^p #p  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 7Oa#c<2]  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Pg0x/X{t  
SiteFileFetch fileFetch = new SiteFileFetch(bean); mzaWST]  
fileFetch.start(); vv3* j&I  
} 0d"[l@UU0  
catch(Exception e){e.printStackTrace ();} &0OG*}gi  
a LroD$#  
mPtZO*Fc  
} 4$iz4U:P  
q77;ZPfs8  
/ivJsPH  
public static void main(String[] args) Pmr5S4Ka  
{ 6S'yZQ|b  
new TestMethod(); 8>2.UrC  
} j9x<Y]  
} fcRxp{*zO  
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