http断点续传简单实现（java)

/* crJyk#_  
**SiteFileFetch.java BO b#9r  
*/ Ny;(1N|&3  
package NetFox; &b 2Vt  
import java.io.*; RhG9Xw9  
import java.net.*; %} _{_Z  
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public class SiteFileFetch extends Thread { ]F@XGJN  
( _ZOUMe  
[Hn4&PET  
SiteInfoBean siteInfoBean = null; //文件信息Bean dpO ZqhRs.  
long[] nStartPos; //开始位置 io]e]m%  
long[] nEndPos; //结束位置 1)aB']K%  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 :bLL
N  
long nFileLength; //文件长度 m
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boolean bFirst = true; //是否第一次取文件 zY<=r.m4  
boolean bStop = false; //停止标志 c}II
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File tmpFile; //文件下载的临时信息 uvK1gJrA)  
DataOutputStream output; //输出到文件的输出流 R}Ih~zw  
:N~1fvx  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ;a/Gs^W  
public SiteFileFetch(SiteInfoBean bean) throws IOException Tn+6:<OFdO  
{ Q0f7gY1-%  
siteInfoBean = bean; ZJ} V>Bu-  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); i
/nA(%_  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); AepAlnI@  
if(tmpFile.exists ()) /++CwRz@Gm  
{ -d+q+l>0  
bFirst = false; Qwn/ ,  
read_nPos(); 2$^n@<uZ@  
} s%nx8"  
else ).TQYrs  
{ ~+{OSx<S  
nStartPos = new long[bean.getNSplitter()]; 7m6@]S6  
nEndPos = new long[bean.getNSplitter()]; DiyviH  
} +$:bzo_u  
CT@JNG$<"  
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} ocCC63J  
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public void run() vdloh ,  
{ F:.rb Ei  
//获得文件长度 (gQ^jmZPG  
//分割文件 DFKU?#R  
//实例FileSplitterFetch wRL=9/5(8  
//启动FileSplitterFetch线程 0/d+26lR  
//等待子线程返回 hL#5:~(  
try{ $UMxO`F  
if(bFirst) '~{^c}  
{ GZ#6}/;b  
nFileLength = getFileSize(); `}ak;^Me  
if(nFileLength == -1) $srb!&~_>  
{ /sf:.TpVh  
System.err.println("File Length is not known!"); }qlU  
} 9FT
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else if(nFileLength == -2) r5XG$:$8\  
{ Gn+D%5)$I  
System.err.println("File is not access!"); d]0.6T1[K  
} q;a`*gX^  
else "8wRxDr+  
{ ~y%8uHL:  
for(int i=0;i<nStartPos.length;i++) KH)(xB=  
{ "q(#,,_  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); klduJT >  
} SF2A?L?}+  
for(int i=0;i<nEndPos.length-1;i++) 2]n"7Z8(v8  
{ xmxfXW  
nEndPos = nStartPos[i+1]; zhbp"yju7  
} 9WsPBzi"T  
nEndPos[nEndPos.length-1] = nFileLength; $d M: 5y  
} `y; s1nL  
}  H  
~d :Z|8  
E.]sX_X?  
//启动子线程 7pDov@K<{  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length];  6RV]9  
for(int i=0;i<nStartPos.length;i++) ^GG6%=g'  
{ [pOQpfo\  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), m5lMh14E  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), RwMK%^b  
nStartPos,nEndPos,i); t>QAM6[  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Jw'%[(q Q  
fileSplitterFetch.start(); +!IIt {u  
} $E@L{5Yt  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), |'WaBy1  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); +U9Gj#  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", N"MuAUB:K  
nEndPos = " + nFileLength); pqO}=*v@  
// fileSplitterFetch[nPos.length-1].start(); pmd=3,D'u  
6/@"K HHVe  
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//等待子线程结束 A-e#&pJ  
//int count = 0; r- 0BLq]~{  
//是否结束while循环 i|PQNhUe  
boolean breakWhile = false; euO!+9p  
Hzs]\%"  
|><hdBQXX<  
while(!bStop) = R|?LOEK+  
{  *r Y6  
write_nPos(); (.a:jL$
 
Utility.sleep(500); xg~q'>
 
breakWhile = true; ^~Nz8PCY  
^D8YF  
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for(int i=0;i<nStartPos.length;i++) rMIr&T  
{ ,@ A1eX}  
if(!fileSplitterFetch.bDownOver) 2'_xg~  
{ }:C4T*|  
breakWhile = false; uj|{TV>v9  
break; !={Z]J  
} ;o]'7qGb  
} BX&bhWYGFX  
if(breakWhile) [uP_F
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break; Ql sMMIax  
-M}#-qwf  
;u!qu$O  
//count++; &/*XA  
//if(count>4) ;:Q 5?zM  
// siteStop(); +L1%mVq]y  
} I#QBJ#  
!_rAAY  
[=079UN-X  
System.err.println("文件下载结束！"); mMm_=cfv  
} .|XIF
 
catch(Exception e){e.printStackTrace ();} I=X-e#HM?  
} Wf/Gt\?  
n5dFp%k  
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//获得文件长度 wvsKnYKX  
public long getFileSize() Ub=g<MYHV  
{ Cw]&B  
int nFileLength = -1; {LfVV5
?  
try{ 4VINu9\V  
URL url = new URL(siteInfoBean.getSSiteURL()); _#xS
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); @Y+YN;57  
httpConnection.setRequestProperty("User-Agent","NetFox"); p@]\N  
v 0mc1g+9  
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int responseCode=httpConnection.getResponseCode(); d)F~)}TFM  
if(responseCode>=400) & .VciSq6  
{ o5KpiibFM  
processErrorCode(responseCode); XL>v$7`#  
return -2; //-2 represent access is error I*_@WoI*  
} ^l|{*oj2  
WCT}OiLsL  
/n;-f%dL  
String sHeader; Lbk?( TL  
3a #2 }  
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for(int i=1;;i++) Xwy0dXk
o  
{ =4cK9ac  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 4hdxqI!y2  
//Utility.log(in.readLine()); T!e]=  
sHeader=httpConnection.getHeaderFieldKey(i); )$K )`uqb  
if(sHeader!=null) W]MKc&R  
{  f.acH]p  
if(sHeader.equals("Content-Length")) braHWC'VYg  
{ aOHf#!/"sb  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); f<WP<!N%  
break; aP^,@RrL  
} i:W.,w%8  
} uu L
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else c'nEbelE  
break; /tI8JXcUK  
} n{JBC%^g  
} M72.  
catch(IOException e){e.printStackTrace ();} asqbLtQ  
catch(Exception e){e.printStackTrace ();} _4F(WCco  
j\& `  
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Utility.log(nFileLength); ,.[T]37  
;Ak<O[  
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return nFileLength; PjZsMHW%  
} Ag=>F5  
7YT%.ID  
]w z`j1  
//保存下载信息（文件指针位置） b
b}zn'xC  
private void write_nPos() mn;
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{ KdIX`  
try{ v3!oY t:l  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 'fO[f}oa_.  
output.writeInt(nStartPos.length); Ik2yIf5d  
for(int i=0;i<nStartPos.length;i++) ;0DTf  
{ 3T^f#UT  
// output.writeLong(nPos); -N;$L~`iAt  
output.writeLong(fileSplitterFetch.nStartPos); Vm}OrFA  
output.writeLong(fileSplitterFetch.nEndPos); a@:(L"Or  
} ZHT_o\  
output.close(); _u TaN  
} -t~l!!N(  
catch(IOException e){e.printStackTrace ();} ApHs`0=(  
catch(Exception e){e.printStackTrace ();} [4L[.N@  
} <$bM*5sHF>  
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) =-$>75Z  
//读取保存的下载信息（文件指针位置） t}L kl(  
private void read_nPos() 4FURm@C6  
{ Nn<TPT[,  
try{ wdg,dk9e$  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); =K'X:UM  
int nCount = input.readInt(); AjBwj5K  
nStartPos = new long[nCount]; .l?sYe64S  
nEndPos = new long[nCount]; C+ar]Vi
 
for(int i=0;i<nStartPos.length;i++) " &2Kvsz  
{ "D#+:ix8G|  
nStartPos = input.readLong(); 91%QO?hz  
nEndPos = input.readLong(); BSt^QH-'  
} }jHS  
input.close(); ~I[Z2&I  
} "TW%-67  
catch(IOException e){e.printStackTrace ();} y#F`yXUj  
catch(Exception e){e.printStackTrace ();} GaV6h|6_  
} Q@]~O-  
6.%M:j00E  
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private void processErrorCode(int nErrorCode) kI7c22OJ  
{ ZL/iX~}a'  
System.err.println("Error Code : " + nErrorCode); {8+FxmH  
} ROcI.tL  
fA"N5qQI(  
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//停止文件下载 x(oL\I_Z  
public void siteStop() to9~l"n.s  
{ }j<:hDQP  
bStop = true; y4sKe:@2  
for(int i=0;i<nStartPos.length;i++) nE.w  
fileSplitterFetch.splitterStop(); 4WCWu}  
dH:z_$Mg  
7<FI[  
} [7x,&  
} *_feD+rq  
//负责部分文件的抓取 o/0cd  
**FileSplitterFetch.java iF]G$@rbU  
*/ We%HdTKT  
package NetFox; ;75m 9yGo  
%siBCjvo=  
&b :u~puM  
import java.io.*; JX4uH>6  
import java.net.*; A|jmp~@K)+  
XC44]o4jx  
hr@c7/L  
public class FileSplitterFetch extends Thread { Zo$,{rl  
^`M,ju  
2J?ON|2M  
String sURL; //File URL 9*s''=  
long nStartPos; //File Snippet Start Position u|]{|Ya'%  
long nEndPos; //File Snippet End Position 6/{V#.(  
int nThreadID; //Thread's ID FuqMT`  
boolean bDownOver = false; //Downing is over r~f*aD  
boolean bStop = false; //Stop identical QuFzj`(  
FileAccessI fileAccessI = null; //File Access interface sVXIR  
9$ GAs  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException O7<--  
{ FP
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this.sURL = sURL; `FS)i7-o6  
this.nStartPos = nStart; >ZRCM  
this.nEndPos = nEnd; iczJXA+  
nThreadID = id; /G[2   
fileAccessI = new FileAccessI(sName,nStartPos);//定位 nV`n=x  
} *xHj*  
=AaTn::e/  
4pU|BL\j  
public void run() WFHS8SI  
{ * AsILK0  
while(nStartPos < nEndPos && !bStop) ~|y$^qy?U  
{ 'v|R' wi\  
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?a)X)#lQ  
try{ aTi2=HL=S  
URL url = new URL(sURL); ,orq&#*Wd  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); :Q\Es:y  
httpConnection.setRequestProperty("User-Agent","NetFox"); YoC{ t&rY  
String sProperty = "bytes="+nStartPos+"-"; v67utISNI  
httpConnection.setRequestProperty("RANGE",sProperty); -@*[   
Utility.log(sProperty); >.sdLA Si  
6?B'3~r  
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InputStream input = httpConnection.getInputStream(); ,[gu7z^|  
//logResponseHead(httpConnection); lI,lR  
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!u)>XS^E
  
byte[] b = new byte[1024]; W~" 'a9H/  
int nRead; gteG*pi  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ajr);xd  
{ _ ^ JhncL  
nStartPos += fileAccessI.write(b,0,nRead); K;ncviGu  
//if(nThreadID == 1) [u?*' c{  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); `5SLo=~  
} i sK_t*  
:A,g:B  
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Utility.log("Thread " + nThreadID + " is over!"); mZ%"""X\Ei  
bDownOver = true; f{i~hVF  
//nPos = fileAccessI.write (b,0,nRead); 2Ra}&ie  
} 5Q/&,NP  
catch(Exception e){e.printStackTrace ();} HACY  
} v8{ jE
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} , ZisJksk  
6 b/UFO  
cA,`!dG2,  
//打印回应的头信息 +ConK>;  
public void logResponseHead(HttpURLConnection con) <R;t>~8x  
{ <^+x}KV I  
for(int i=1;;i++) f0^;*Y  
{ 1\t#*N  
String header=con.getHeaderFieldKey(i); g$^:2MT"aQ  
if(header!=null) 1')_^
]  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ~]w|ULNa3|  
Utility.log(header+" : "+con.getHeaderField(header)); 4J~ZZ  
else bUcEQGHcZ=  
break; m2{DLw".  
} ,ORwMZtw{H  
} ;nSOeAF)Q  
. X:
 
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public void splitterStop() yG v7^d  
{ R>C^duos.  
bStop = true; <2.87:  
} DqH?:`G  
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} >b1#dEY  
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q HU}EEv  
/* Tr6J+hS  
**FileAccess.java }CM</  
*//文件访问(定位，写) }EMds3<  
package NetFox; R(^2+mV?  
import java.io.*; K|Cb6''  
`SfBT1#5G  
|_h$}~;  
public class FileAccessI implements Serializable{ qN=l$_UD  
Nn/f*GDvK  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 HxAN&g*:  
RandomAccessFile oSavedFile; 39yp1  
long nPos; #$dEg  
!T|q/ri  
j@o \d%.'!  
public FileAccessI() throws IOException lSG"c+iV  
{ \jpm   
this("",0); _\ &N<  
} Gi+ZI{)  
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public FileAccessI(String sName,long nPos) throws IOException 2=%R>&]*  
{ 0K<|>I  
oSavedFile = new RandomAccessFile(sName,"rw"); Cu $mb}@  
this.nPos = nPos; f(*ygI  
oSavedFile.seek(nPos); !H^e$BA  
} T?4I\SG  
F,.dC&B
 
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public synchronized int write(byte[] b,int nStart,int nLen) J1\H^gyW)  
{ uD0<|At/  
int n = -1; _!ITCkBj  
try{ W1!Nq`  
oSavedFile.write(b,nStart,nLen); u}0U!
 
n = nLen; |y%M";MI  
} -Pt']07E  
catch(IOException e) q(XO_1W0V  
{ oro^'#ki  
e.printStackTrace (); DkA@KS1Dq  
} X~VJO|k pz  
n# 4e1n+I  
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return n; - %'ys  
} \2^_v' >K  
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} \1MMz Z4rf  
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/* .QLjaEja  
**SiteInfoBean.java AM:
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*/ xsERnF>`  
package NetFox; )OE!vA  
mzbMX <  
K9=f`JI9  
public class SiteInfoBean { INF}~DN]  
_q
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private String sSiteURL; //Site's URL JBMJR  
private String sFilePath; //Saved File's Path "V3f"J?  
private String sFileName; //Saved File's Name wgcKeT
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private int nSplitter; //Count of Splited Downloading File &57s//PrX  

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public SiteInfoBean() mhi^zHpa  
{//nSplitter的缺省值为5 6!A+$"  
//default value of nSplitter is 5 -oMp@2\e  
this("","","",5); *t_JR  
} Z[%vO?,  
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;hZ^zL  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) x*a^msY%  
{ 7\<}378/^  
sSiteURL= sURL; HlgkW&}c^  
sFilePath = sPath; @3Nvf}He  
sFileName = sName; )Rj,PF-9Z[  
this.nSplitter = nSpiltter; Y q(CD!  
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} &Ndq^!e  
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`&/~%>  
public String getSSiteURL() ~fz9AhU8  
{ ^b&U0k$R  
return sSiteURL; %$ ^eY'-'  
} }pOJM&I  
<c_'(   
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public void setSSiteURL(String value) A[8vD</}_  
{ c0.? d]  
sSiteURL = value; !McRtxq?~  
} Scz/2vNi`  
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586lN22xM  
public String getSFilePath() q6AL}9]9  
{ t +h}hL  
return sFilePath; )Q)H!yin  
} bSm*/Q  
yN:U"]glC  
4&}dA^F  
public void setSFilePath(String value) ]MaD7q>+R  
{ .3:s4=(f  
sFilePath = value; ~0T,_N  
} $(N+E,XB  
,cwjieM  
+WfO2V.
 
public String getSFileName() 1 R,?kUa  
{ %O02xr=  
return sFileName; o?((FW5.;  
} MgrJ ;?L  
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public void setSFileName(String value) ;Sw%t(@  
{  r NT>{  
sFileName = value; a8v9j3.  
} Wo,"$Z6B  
K
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;pVnBi  
public int getNSplitter() -XMWN$Ah  
{ .u^4vVz  
return nSplitter; Cw,;>>Y_b<  
} .NRSBk  
mY0FewwTy  
*]+5T-R% $  
public void setNSplitter(int nCount) "[Hn G(gA  
{ x2.YEuSMC  
nSplitter = nCount; z3C@0v=u>  
} }e8u p*#me  
} SE0&CV4  
]h4r@L3  
V4tObZP3Ff  
/* AB[#
  
**Utility.java K/IG6s;Xj  
*/  zPW_  
package NetFox; i+4!nf{K  
p8|u0/;k  
c^W \0  
public class Utility { 6sz:rv}  
x/,(G~  
:7DXLI|L#?  
public Utility() CoTe$C7  
{ |\6Ff/O  
DQyy">]Mh  
NsUP0B}.  
} Uk<2X
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fiZq C?(  
//线程睡眠 y*7<tj.`b0  
public static void sleep(int nSecond) qJ%AbdOI8  
{ ^7,`6g
 
try{ {qbxiL-  
Thread.sleep(nSecond); SioP`*,}  
} "e@?^J)  
catch(Exception e) VB&`g<  
{ E.%_i8s  
e.printStackTrace (); 6o=Q;Mezl  
} _n=,H  
} -E,p[Sp  
Jt|W%`X>D  
//日志 vq-#%o  
public static void log(String sMsg) ZJ'Tb<fP  
{
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System.err.println(sMsg); Ew>lk9La(  
} $4u8"ne)  
}&Kl)2:O  
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public static void log(int sMsg) 8XhGo2zf  
{ y_}jf,b4  
System.err.println(sMsg); <MzXTy3\  
} 8}>s{u;W  
} 94b* !Z  
{~{</ g/  

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/* t;L7H E@Y  
**TestMethod.java d[$YTw  
*/ O#3PUuE%d  
package NetFox; f0]`TjY  
r0j+P%  
' T%70)CM~  
public class TestMethod { Ot
([5/K  
*Vr;rk  
) ={ H  
public TestMethod()
-'~61=PD  
{ ///xx/weblogic60b2_win.exe X\HP&;Wd  
try{ M.0N`NmS  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); f\h|Z*Bv  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); %IHra6  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 3U&rK)F  
fileFetch.start(); Bl*.N9*  
} ZP;WXB`  
catch(Exception e){e.printStackTrace ();} t^SND{[WcM  
gQ=l\/H  
`~+[pY1r  
} 3Q~zli:  
p}d+L{"V  
R/@n+tbe  
public static void main(String[] args) JsV-:J  
{ Mv7=ZAm  
new TestMethod(); W}rLHAaDh  
} {mmQv~|5q  
} NK$BF(HBi  
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