http断点续传简单实现（java)

/* 1r<'&f5  
**SiteFileFetch.java 4TcW%  
*/ j^D/,SW  
package NetFox; 1t7T\~+F  
import java.io.*; hmv*IF.  
import java.net.*; H4BuxM_r  
! ;R}=  
"SpsSQ  
public class SiteFileFetch extends Thread { aK8X,1g%)  
@Dd3mWKq  
on f
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SiteInfoBean siteInfoBean = null; //文件信息Bean Olr'n% }  
long[] nStartPos; //开始位置 ;RW5XnVx  
long[] nEndPos; //结束位置 cB2~W%H  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 7+m.:~H3}  
long nFileLength; //文件长度 <4*)J9V^s=  
boolean bFirst = true; //是否第一次取文件 U-#vssJhk  
boolean bStop = false; //停止标志 K?=g IC:  
File tmpFile; //文件下载的临时信息 rM20Y(|  
DataOutputStream output; //输出到文件的输出流 <'O|7. ^^  
<^adt *m  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） )>!y7/3  
public SiteFileFetch(SiteInfoBean bean) throws IOException -V:7j8  
{ "=UhTE  
siteInfoBean = bean; =Ct$!uun  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Bacmrf  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); "SV/'0  
if(tmpFile.exists ()) 8b $e)  
{ #|6M*;lN|  
bFirst = false; ?8$h%Ov-  
read_nPos(); m"vWu0
/#  
} 'l._00yu  
else sB<y(}u  
{ xOc&n0}%  
nStartPos = new long[bean.getNSplitter()]; U zMIm  
nEndPos = new long[bean.getNSplitter()]; hFDo{yI  
} `YK#m4gc  
/ KxZ+Ww>v  
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} <is%lx(GDX  
0vcFX)]yW  
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public void run() |$c~Jq  
{ M;E$ ]Z9  
//获得文件长度 nY_+V{F  
//分割文件 Cx ;n#dn*  
//实例FileSplitterFetch HeM-  
//启动FileSplitterFetch线程 ASaNac-3  
//等待子线程返回 jNP%BNd1f  
try{ E^t}p[s  
if(bFirst) D<xDj#Z~1  
{ o*s3"Ib  
nFileLength = getFileSize(); @%[ VegT  
if(nFileLength == -1) H)i%\7F5  
{ 0/zgjT|fe  
System.err.println("File Length is not known!"); w(nQ:;oC  
} -\}Ix>  
else if(nFileLength == -2) m/NXifi8l  
{ r<-@.$lf  
System.err.println("File is not access!"); )[5.*g@  
} ~9dAoILrl  
else mf)E%qo  
{ hB-<GGcO <  
for(int i=0;i<nStartPos.length;i++) {&.?u1C.\  
{ 1fU~&?&-u  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); x-@6U  
} ri1:q.:I]  
for(int i=0;i<nEndPos.length-1;i++) D2Dk7//82Y  
{ p`3$NCJN  
nEndPos = nStartPos[i+1]; =s1Pf__<k  
} /SQ1i}%  
nEndPos[nEndPos.length-1] = nFileLength; W&Kjh|[1QZ  
} #nJ&`woZt  
} Ss#UX_DT_  
;>B06v  
Zcxj.F(,  
//启动子线程 2^=.jML[  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Fx'E"d  
for(int i=0;i<nStartPos.length;i++) a1# 'uS9W  
{ )>rHM6-W  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), glP W9q,f  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), D``>1IA]  
nStartPos,nEndPos,i); J1{ucFa  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); {AMoE+U  
fileSplitterFetch.start(); \o{rw0w0  
} nwPU{4#l<  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), U Zc%XZ`"V  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 5mB'\xGO2  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", /V)4B4  
nEndPos = " + nFileLength); cp<jwcc!  
// fileSplitterFetch[nPos.length-1].start(); 4+15`  
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//等待子线程结束 #~`]eM5`J  
//int count = 0; N3rQ]HZiP  
//是否结束while循环 .q9wyVi7GI  
boolean breakWhile = false; {>R'IjFc  
\Yd 0oe82  
F otHITw[  
while(!bStop) S K7b]J>  
{ 3Mt Alc0xp  
write_nPos(); Z@bGLS  
Utility.sleep(500); <<.%Gk  
breakWhile = true; Q XV8][  
f!aE/e\  
a#4 'X*  
for(int i=0;i<nStartPos.length;i++) iHL`r1I!  
{ =Frbhh57  
if(!fileSplitterFetch.bDownOver) JypXQC}~  
{ ^NPbD<~Lb  
breakWhile = false; ;IYH5sG{  
break; yCOIv!/zy  
} kw.IVz<  
} zS+_6s  
if(breakWhile) a5xmIp@6  
break; K JX@?
1"  
@CU~3Md*  
%1jApCJ  
//count++; ,,KGcDBj  
//if(count>4) Oe[qfsdW  
// siteStop(); {-?8r>  
} wz(D }N5  
{IpIQ-@l  
]h6mJ{k  
System.err.println("文件下载结束！"); I_h{n{,sr  
} ;&%G)f  
catch(Exception e){e.printStackTrace ();} :u$+lq  
} 5};$>47m  
%"> Oy&3  
f8'$Mn,  
//获得文件长度 0{ ;[k  
public long getFileSize() p&#*  
{ OnKPD=<
 
int nFileLength = -1; w(xRL#%  
try{ s"solPw  
URL url = new URL(siteInfoBean.getSSiteURL()); @\UoZv(  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); MlM2
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httpConnection.setRequestProperty("User-Agent","NetFox"); 5h4E>LB.B  
+e6c4Tw/  
6(X5n5C  
int responseCode=httpConnection.getResponseCode(); KZxA\,Y'5  
if(responseCode>=400) S=wJ{?gzAK  
{ K{s%h0  
processErrorCode(responseCode); yU@~UCmja  
return -2; //-2 represent access is error GK/Q]}Q8pZ  
} -MqWcB9&  
8uO@S*)0  
M5Twulz/w  
String sHeader; b:iZ.I  
;|Z;YK@20  
;\$P;-VY  
for(int i=1;;i++) joN}N}U  
{ CY4_=  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); h
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//Utility.log(in.readLine()); ;^,2 QsM  
sHeader=httpConnection.getHeaderFieldKey(i); N+vU@)_lC  
if(sHeader!=null) ecH-JPm'  
{ <}E^r_NvD  
if(sHeader.equals("Content-Length")) | 3`qT#p{  
{ >Ufjmm${  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); R
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break; FBGHVV w!  
} 6rnehv!p  
} Ohm
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else a9E!2o+,  
break; 4pF U`g=  
} %}=$HwN)  
} / -=(51}E  
catch(IOException e){e.printStackTrace ();} p0.?R  
catch(Exception e){e.printStackTrace ();} i;0`d0^  
~?}/L'q!b  
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Utility.log(nFileLength); I_yIVw;  
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c=2e?  
return nFileLength; G
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} DJE/u qE
 
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\2<2&=h?  
//保存下载信息（文件指针位置） =&fBmV  
private void write_nPos() ;f-|rC_"  
{ Q:~w;I  
try{ 71tMX[x  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Et'C4od s  
output.writeInt(nStartPos.length); bIm$7a`T  
for(int i=0;i<nStartPos.length;i++) $UjSP  
{ JMOP/]%D  
// output.writeLong(nPos); &Jj> jCg  
output.writeLong(fileSplitterFetch.nStartPos); dITnPb)i  
output.writeLong(fileSplitterFetch.nEndPos); 7o z(hO~  
} Za!c=(5  
output.close(); [6S"iNiyKT  
} MatC2-aV1  
catch(IOException e){e.printStackTrace ();}
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catch(Exception e){e.printStackTrace ();} (r[<g*+3  
} 8"LaP3U  
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:,q3?l6  
//读取保存的下载信息（文件指针位置） &SN$D5U'  
private void read_nPos() !P Gow  
{ 0acY@_  
try{ !CB
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DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 0v7;ZxD  
int nCount = input.readInt(); f!$J_dz  
nStartPos = new long[nCount]; ` `;$Kr  
nEndPos = new long[nCount]; Mqh~5NM  
for(int i=0;i<nStartPos.length;i++) 6vaxp|D  
{ d7^XP  
nStartPos = input.readLong(); *VlYl"  
nEndPos = input.readLong(); J$I1*~I4v  
} \[oHt:$do  
input.close(); O[L8(+Sn  
} BWPYHWW}E  
catch(IOException e){e.printStackTrace ();} 5ZKnxEW,(  
catch(Exception e){e.printStackTrace ();} 2mlE;.}8  
} |%V.Lae  
*Yr-:s9J9  
?*s!&-KI  
private void processErrorCode(int nErrorCode) zBs7]z!eP  
{ nIi_4=Z  
System.err.println("Error Code : " + nErrorCode); 'j)eqoj  
} a;S^<8  
Y+jKP*ri  
|TUpv*pq  
//停止文件下载 1I+5  
public void siteStop() /*O,T  
{ B7PmG f)b  
bStop = true; ~Op1NE  
for(int i=0;i<nStartPos.length;i++) ]s -6GT  
fileSplitterFetch.splitterStop(); 5,c`  
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@Hf}PBb  
} Kmnr}Lp9  
} $F-XXBp  
//负责部分文件的抓取 )g --=w3  
**FileSplitterFetch.java &rd(q'Vi  
*/ h[8y$.YsC  
package NetFox; `l+SJLyJ%  
1}uDgz^  
`@eH4}L*  
import java.io.*; L&N"&\K2U  
import java.net.*; Xp~]kRm9  
X2uX+}h*tA  
u .2sB6}  
public class FileSplitterFetch extends Thread { 19.cf3Dh  
".)_kt[  
H+;wnI>@  
String sURL; //File URL Ax0,7,8y  
long nStartPos; //File Snippet Start Position ZYsFd_  
long nEndPos; //File Snippet End Position cBI)?  
int nThreadID; //Thread's ID xB(:d'1|  
boolean bDownOver = false; //Downing is over Rpk`fxAO  
boolean bStop = false; //Stop identical Y2X1!Em>B  
FileAccessI fileAccessI = null; //File Access interface rxK0<pWJhx  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException RNdnlD#P  
{ jEsTw_  
this.sURL = sURL; %jxuH+L   
this.nStartPos = nStart; m=MT`-:  
this.nEndPos = nEnd; JC"K{V{  
nThreadID = id; X6.O;  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 OQ7c|O  
} ?X'* p<`  
X^Y9T`mQ}  
WQpJd7
  
public void run() / D ]B  
{ zb/Xfu.)?6  
while(nStartPos < nEndPos && !bStop) pYVy(]1I(3  
{ $/TA5h  
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try{ zt2-w/[Q  
URL url = new URL(sURL); Wd
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); qm=F6*@}  
httpConnection.setRequestProperty("User-Agent","NetFox"); t4_K>Mj+d  
String sProperty = "bytes="+nStartPos+"-"; 6\Vu#r  
httpConnection.setRequestProperty("RANGE",sProperty); o'7ju~0L  
Utility.log(sProperty); X-$td~r  
kA<r:/  
!>y}Xq{bm3  
InputStream input = httpConnection.getInputStream(); gVU\^KN]  
//logResponseHead(httpConnection); )95yV;n   
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byte[] b = new byte[1024]; 1vs>2` DLa  
int nRead; 0Eu$-)  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) W4*BR_H&*  
{ 
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nStartPos += fileAccessI.write(b,0,nRead); 0a6@HwO  
//if(nThreadID == 1) q;../h]Ne  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Gd6 ;'ZCmY  
} {2k< k(,  
aE+$&_>ef  
,XG|oo-  
Utility.log("Thread " + nThreadID + " is over!"); $
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bDownOver = true; }0*ra37z>  
//nPos = fileAccessI.write (b,0,nRead); &@utAuI  
} &9dr+o-(~  
catch(Exception e){e.printStackTrace ();} 0 ,Qj:  
} sQ:VrXwP  
} JJ9e{~0I  
FR,#s^kF  
y8*@dRrq  
//打印回应的头信息 mz$Wo *FB  
public void logResponseHead(HttpURLConnection con) f9
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{ renmz,dJ,  
for(int i=1;;i++) bOSYr<R&  
{ CDwIq>0j  
String header=con.getHeaderFieldKey(i); [^d6cMEOlc  
if(header!=null) q8xc70: R  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); _l!U[{l*d  
Utility.log(header+" : "+con.getHeaderField(header)); 9g&)6,<  
else 76_8e{zbr  
break; wdcryejCkr  
} E}b>7L&w  
} .`Old{<  
?^48Zq6wM  
{`Fx~w;i  
public void splitterStop() #!=>muZt  
{ 3w^J"O/T  
bStop = true; Z!RRe]"y  
} +ersP@G  
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=Mu'+,dT  
} W:{PBb"x8  
}Cmj(k`~  
h*\TCl)  
/* ^{fi^lL=  
**FileAccess.java K+7yUF8XP  
*//文件访问(定位，写) APQQ:'>N4~  
package NetFox; #}t1   
import java.io.*; X$uz=)  
lN)Y  
vA2,&%jw  
public class FileAccessI implements Serializable{
EN-8uY.  
:rTKqX&"j  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 9&XV}I,~?|  
RandomAccessFile oSavedFile; zqvRkMWcM  
long nPos; XMeL^|D  
_ r^90  
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public FileAccessI() throws IOException 6cQeL$,SQ  
{ gc,J2B]61  
this("",0); \sHy.{  
} J:g<RZZ1  
V`R)#G>IH%  
<@U.   
public FileAccessI(String sName,long nPos) throws IOException U!a!|s>  
{ vR%j#v|s  
oSavedFile = new RandomAccessFile(sName,"rw"); h7de9Rt  
this.nPos = nPos; Wk\mgGn+  
oSavedFile.seek(nPos); M9(ez7Z  
} dJ%wVY0z=  
LY\d
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,u?wYW;  
public synchronized int write(byte[] b,int nStart,int nLen) (<]\,pP0_  
{ ;1*m}uNz  
int n = -1; TdNuD V  
try{ -!'Oy%a#  
oSavedFile.write(b,nStart,nLen); 1EC-e|M.  
n = nLen; bxd
3  
} #L@} .Giz  
catch(IOException e) )Y&MIJ7>@  
{ jy\W_CT  
e.printStackTrace (); RsqRR`|X?  
} cW
81  
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*<`7|BH3  
return n; Z-^uM`],G  
} iX8h2l  
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} 936Ff*%(l  
_L&n&y1+%  
V]l&{hl,  
/* Gt^|+[gD  
**SiteInfoBean.java s jL
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*/ :Az8K)  
package NetFox; 8 *4@-3Sx  
MuDFdbtR  
}Kvh`@CiJ  
public class SiteInfoBean { l 8O"w&  
o/t
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.+{nA}Bc  
private String sSiteURL; //Site's URL l?3vNa FeR  
private String sFilePath; //Saved File's Path %/{IssCR7  
private String sFileName; //Saved File's Name Y5
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private int nSplitter; //Count of Splited Downloading File R'*<A3^  
=]=B}L`  
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public SiteInfoBean() 8ku? W  
{//nSplitter的缺省值为5 I#i?**  
//default value of nSplitter is 5 GwgFi@itN  
this("","","",5); 9b?
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} .yZK.[x4  
o `b`*Z  
Iv'RLM  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ;):8yBMk  
{ $a`J(I  
sSiteURL= sURL; PYdIP\<V  
sFilePath = sPath; xCR; K]!  
sFileName = sName; Kg4QT/0VA  
this.nSplitter = nSpiltter; "V:  
}*?yHJ3  
@''&nRC1  
} Jb(
DJ-&  
JzHqNUn*M  
Bs_S.JP<`  
public String getSSiteURL() ;l$9gD>R  
{ ~RcNZ\2y  
return sSiteURL; u8|@|t  
} 3Z_t%J5QZ$  
CT|z[^  
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public void setSSiteURL(String value) 0('OyH)  
{ q_-ma_F#s  
sSiteURL = value; +T-@5v[  
} 0Xp nbB~~I  
qpoquWZ  
x:p}
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public String getSFilePath() D0f*eSXE{  
{ XFtOmY
 
return sFilePath; #]@9qPyn  
} Nfr:`$k  
UMT\Q6p  
' Q\@19  
public void setSFilePath(String value) I"B8_  
{ A_@I_V$  
sFilePath = value; h5x*NM1Ih  
} R
|-6o)$  
{z=j_;<]  
P= e4lF.  
public String getSFileName() ]Qd{ '}+  
{ b9`iZ  
return sFileName; ]+mjOks~  
} F{;; :  
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Hc M~
  
public void setSFileName(String value) kQy&I3  
{ f?Z|>3.2  
sFileName = value; `{DG;J03[  
} uWh|C9Y!A  
$.wA?`1aSk  
u %'y_C3  
public int getNSplitter() {H+?z<BF<  
{ m#*h{U$  
return nSplitter; wEE2a56L-  
} i=-8@  
NIaF5z  
=rEA:Q`~w  
public void setNSplitter(int nCount) 7RD$=?oO'  
{ 3^XVQS***  
nSplitter = nCount; "NKf0F  
} $6# lTYN~  
} yQ'eu;+]  
%
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zi }(^~Fe  
/* R
5~gH6K|  
**Utility.java wYjQV?,  
*/ +1/b^Ac  
package NetFox; tfA}`
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{\EOo-&A  
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public class Utility { ck$M(^)l  
Ib6(Bp9.L  
srK53vKMHW  
public Utility() '#W_boN  
{ \DS^i`o)rY  
)&,K94  
tFiR!f)  
} [zQWyDu  
[x5
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//线程睡眠 {]`p&@  
public static void sleep(int nSecond) #9\THfb  
{ pv&^D,H,  
try{ csDQva\  
Thread.sleep(nSecond); Xu6K%]i^  
} bAiJn<  
catch(Exception e) nvt$F%+  
{ M|8 3HTJ  
e.printStackTrace (); +xp*]a  
} ! Mo`^t  
} Y@%`ZPJ  
G6Nb{m  
//日志 MMgx|"  
public static void log(String sMsg) DsGI/c  
{
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System.err.println(sMsg); =EpJZt  
} =cn~BnowY  
Ri @`a  
X;VQEDMPU  
public static void log(int sMsg) |')-VhLLK  
{ vq>l>as9O  
System.err.println(sMsg); h e&V# #  
} wa ky<w,  
} lhO2'#]i  
ehT%s+aUw  
*_"u)<J  
/* TzKK;(GX  
**TestMethod.java /g76Hw>H  
*/ 7
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package NetFox; p`P~i&_  
p3yU:q#A  
EB,4PEe:  
public class TestMethod { &{z<kmc$6  
cp%ii'  
<3Gqv9Y&  
public TestMethod() CT*,<l-D  
{ ///xx/weblogic60b2_win.exe @;Y~frT  
try{ c!wtf,F  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 3n48%
5  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); .=<$S#x^Hb  
SiteFileFetch fileFetch = new SiteFileFetch(bean); CS@&^SEj  
fileFetch.start(); K5k?H  
}
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catch(Exception e){e.printStackTrace ();} A'-_TFwW  
j*3}1L4P  
>|*yh~  
} _^\$"nw  
n:4uA`Vg  
d,9`<1{9  
public static void main(String[] args) T3pdx~66  
{ 926Tl  
new TestMethod(); JhX=l-?  
} !'0S0a8
 
} DtF}QvA  
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