http断点续传简单实现（java)

/* +2f
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**SiteFileFetch.java )?IA`7X  
*/ =ObtD"  
package NetFox; ~q|e];tA  
import java.io.*; <W%Z_d&Xv  
import java.net.*; xv%USm  
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public class SiteFileFetch extends Thread { MMr7,?,$  
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SiteInfoBean siteInfoBean = null; //文件信息Bean |QTqa~~B  
long[] nStartPos; //开始位置 8EEQV}4  
long[] nEndPos; //结束位置 IS4K$Ac.  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 59Q Q_#>  
long nFileLength; //文件长度 32|L $o  
boolean bFirst = true; //是否第一次取文件 $H@)hY8wA  
boolean bStop = false; //停止标志 2CgIY89O  
File tmpFile; //文件下载的临时信息 }=m?gF%3  
DataOutputStream output; //输出到文件的输出流 jMWwu+w  
+U)|&1oa  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） bnY8.Lpf|  
public SiteFileFetch(SiteInfoBean bean) throws IOException UpseU8Wo  
{ FRQ("6(  
siteInfoBean = bean; jLS]^|  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); {ro!OuA  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 7`<? fO  
if(tmpFile.exists ()) X6*y/KGN  
{ la{uJ9Iw@}  
bFirst = false; +siNU#!  
read_nPos(); 8Y~T$Yj^  
} [%,=

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else PyxN_agf  
{  mFoK76  
nStartPos = new long[bean.getNSplitter()]; -XIvj'u  
nEndPos = new long[bean.getNSplitter()]; y$9t!cx  
} dB/I2uGl>  
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} `[:1!I.}-  
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public void run() Ul0<Zxv  
{ bK%tQeT  
//获得文件长度 c!wB'~MS#  
//分割文件 ! e,(Zz5  
//实例FileSplitterFetch s:F+bG}|  
//启动FileSplitterFetch线程 WvzvGT=  
//等待子线程返回 5d{Ggg{s  
try{ D|OX]3~  
if(bFirst) T1D7H~\lG  
{ puDy&T  
nFileLength = getFileSize(); :I1bGa&I  
if(nFileLength == -1) y9:|}Vh  
{ #*?a"  
System.err.println("File Length is not known!"); y
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} E-l>z%  
else if(nFileLength == -2) 16xM
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{ ,~c:P>v=  
System.err.println("File is not access!"); O(CUwk  
} ,OG sx  
else 24]O0K  
{ }&ZO q'B  
for(int i=0;i<nStartPos.length;i++) )0!hw|0|  
{ 4uD!-1LT@  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); *|MPYxJ<  
} XVE(p3-  
for(int i=0;i<nEndPos.length-1;i++) E+csK
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{ PJO +@+"{@  
nEndPos = nStartPos[i+1]; :QB Wy  
} Au@U;a4UU  
nEndPos[nEndPos.length-1] = nFileLength; =p ^Sn
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} q^k6.5*"  
} Bz]j&`  
fk;39$[  
s:,BcVLx^  
//启动子线程 L~CwL  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 3/P
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for(int i=0;i<nStartPos.length;i++) OV^) N  
{ t d-EB&i\  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), N'3Vt8o,  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), (hs[B4nV  
nStartPos,nEndPos,i); V;Te =
4  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); m'@NF--#Oq  
fileSplitterFetch.start(); :p5V5iG  
} #|xK>;  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), nu|;(ly  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); %Gh!h4Pv  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", utfD$8UI  
nEndPos = " + nFileLength); !Zlvz%X  
// fileSplitterFetch[nPos.length-1].start(); ney6N@  
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gfR B  
//等待子线程结束 pk:YjJs  
//int count = 0; xOp8[6Ga'  
//是否结束while循环 oX8e}  
boolean breakWhile = false; o&-q.;MY  
lL/|{A|-j  
P0Z1cN}  
while(!bStop) [2WJ>2r}6  
{ mtOCk 5E  
write_nPos(); E0o=  
Utility.sleep(500); |Rf4^vN  
breakWhile = true; $&OoxC  
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for(int i=0;i<nStartPos.length;i++) gR )xw)!  
{ ~kj1L@gy  
if(!fileSplitterFetch.bDownOver) W4Tuc:X5  
{ ^`!5!|  
breakWhile = false; NffZttN  
break; 4en[!*  
}
]hJ#%1  
} z GhJ  
if(breakWhile) nB[Aw7^|A  
break; 0hp*(, L  
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cNZuwS~,  
//count++; y 4j0nF  
//if(count>4) mQ*:?\@  
// siteStop(); /r^J8B*  
} A(S=  
7Y"CeU-S  
/ q*n*j  
System.err.println("文件下载结束！"); _3i.o$GO  
} xlg6cO  
catch(Exception e){e.printStackTrace ();} k z"F4?,  
} B{hP#bYK  
?ey!wcv~  
*G"L]N
q#  
//获得文件长度 +] s"*'V$  
public long getFileSize() ^rO3B?_  
{ 0pYO-@E  
int nFileLength = -1; 2m7Z:b  
try{ |gxT-ZM  
URL url = new URL(siteInfoBean.getSSiteURL()); ;nW#Dn9  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); (,z0V+!  
httpConnection.setRequestProperty("User-Agent","NetFox"); =BzyI  
G}<%%U D  
3GqvL_  
int responseCode=httpConnection.getResponseCode(); U bUl]  
if(responseCode>=400) @F%H 1  
{ X458%)G!(K  
processErrorCode(responseCode); cOkjeHs 5  
return -2; //-2 represent access is error %eW[`uyV  
} A2LqBirkl  
wDJbax?  
TY6 D.ikA  
String sHeader; MBXja#(k  
g?'pb*PR  
1iyd{r7|  
for(int i=1;;i++) %%5K%z,R#  
{ k`[ L  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); u2%/</]h  
//Utility.log(in.readLine()); MY1s  
sHeader=httpConnection.getHeaderFieldKey(i); XaOq&7  
if(sHeader!=null) ig(dGKD\=9  
{ /G[; kR"  
if(sHeader.equals("Content-Length")) ~Y]*TP  
{ BiI?eT+  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); RKB--$ibj  
break; K89 AZxH  
} i]oSVXx4WC  
} OT/*|Pn9  
else Sg;c|u  
break; S,A\%:Va  
} :j2G0vHIl(  
} zOO:`^ m  
catch(IOException e){e.printStackTrace ();} ]"?+R+  
catch(Exception e){e.printStackTrace ();} 2@ 4^ 81
 
lrQ +G@#  
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Utility.log(nFileLength); rBG8.E36J  
"uK`!{  
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return nFileLength; $42%H#  
} CtItzp  
/4w"akB|P  
Ck
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//保存下载信息（文件指针位置） MW&ww14  
private void write_nPos() O :P%gz4  
{ E07g^y"}i  
try{ #SWL$Vm>  
output = new DataOutputStream(new FileOutputStream(tmpFile)); (KQAKEhD!  
output.writeInt(nStartPos.length); wbg_%h:  
for(int i=0;i<nStartPos.length;i++) ,jVj9m  
{ =pHW
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// output.writeLong(nPos); p<hV7x-{  
output.writeLong(fileSplitterFetch.nStartPos); 'U=D6X%V9m  
output.writeLong(fileSplitterFetch.nEndPos); A'(v]w  
} U-+%e:v  
output.close(); uEp v l  
} /Hxz@=LC1  
catch(IOException e){e.printStackTrace ();} >(>Fx\z}  
catch(Exception e){e.printStackTrace ();} 1%W|>M`  
} h!#!}|Q'  
+Ja9p  
38(Cj~u=3  
//读取保存的下载信息（文件指针位置）  =FZt
 
private void read_nPos() eq>E<X#<  
{ r[2N;U  
try{ GWP;;x%  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); X2ShxD|  
int nCount = input.readInt(); 7|=*z  
nStartPos = new long[nCount]; JUBihw4  
nEndPos = new long[nCount]; }M%U}k]+@  
for(int i=0;i<nStartPos.length;i++) e>"/Uii  
{ Q)pm3Wi  
nStartPos = input.readLong(); Gp6|0:2,L~  
nEndPos = input.readLong(); NUB3L  
} yj]\%3o<Z7  
input.close(); c o}o$}  
} 4.@gV/U(|  
catch(IOException e){e.printStackTrace ();} I^'U_"vB  
catch(Exception e){e.printStackTrace ();} >we/#C"x  
} [Tv!Pc  
6wV{}K^0  
3)SO-Bz\  
private void processErrorCode(int nErrorCode) JStT"*4j  
{ X8U._/'N  
System.err.println("Error Code : " + nErrorCode); i7^_y3dG  
} 7=jeq|&kN  
+jk_tPSe  
n[2[V*|mI  
//停止文件下载 xHN"7j}h  
public void siteStop() pfCNFF*"  
{ C+/D!ZH%P  
bStop = true; O{" A3f  
for(int i=0;i<nStartPos.length;i++) +f)Nf)\q  
fileSplitterFetch.splitterStop(); N?j,'gy4  
tmAc=?|Wa  
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} cB5|%@$I  
} iRwqt-WZ  
//负责部分文件的抓取 g2 dvs  
**FileSplitterFetch.java -u6`B-T  
*/ XO |U4#ya  
package NetFox; r{~K8!=oU]  
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@=jcdn!\M  
import java.io.*; LGb.>O^  
import java.net.*; ,nMc. G3  
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x+h7OvW{  
public class FileSplitterFetch extends Thread { H^s@qh)L  
>j]*=&,7  
|qra.\
 
String sURL; //File URL IyE9G:fY  
long nStartPos; //File Snippet Start Position $;<h<#_n;  
long nEndPos; //File Snippet End Position ; *G[3kk  
int nThreadID; //Thread's ID TI-#\v9  
boolean bDownOver = false; //Downing is over -B\`O*Q  
boolean bStop = false; //Stop identical 2fc8w3  
FileAccessI fileAccessI = null; //File Access interface 22?9KZ`Z=  
#+Lo&%p#3  
?3tR(H<  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException A/NwM1z[o)  
{ "yMr\jt~-  
this.sURL = sURL; 6"Tr$E  
this.nStartPos = nStart; 64s9Dy@%F  
this.nEndPos = nEnd; Xg#g`m%(M  
nThreadID = id; ~mUP!f  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 |L{<=NNs:D  
} `m5cU*@D  
htg+V-,  
LyA=(h6  
public void run() ?5m[Qc(<  
{ '{EBK  
while(nStartPos < nEndPos && !bStop) tYt/m6h  
{ qIQvix$8  
_\ n'uW$  
|N[SCk>Kj  
try{ &o/&T{t}  
URL url = new URL(sURL); :xd&V%u`  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); CORNN8=k  
httpConnection.setRequestProperty("User-Agent","NetFox"); !ViHC}:  
String sProperty = "bytes="+nStartPos+"-"; DvnK_Q!  
httpConnection.setRequestProperty("RANGE",sProperty); ff"Clp  
Utility.log(sProperty); zqAK|jbL  
;2RCgX!'%  
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InputStream input = httpConnection.getInputStream(); Xmy(pV!PF  
//logResponseHead(httpConnection); ]4@z.1Mr  
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byte[] b = new byte[1024]; T8YqCT"EA<  
int nRead; ,)+O.Lf7&.  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) j#%*@]>Tg  
{ g#=^U`y  
nStartPos += fileAccessI.write(b,0,nRead); 0-Xpq,0  
//if(nThreadID == 1) aisX56Lc  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 57+^T}/>  
} %@(6,^3%i  
$Vp&Vc8  
r2QC$V:0  
Utility.log("Thread " + nThreadID + " is over!"); nZQZ!Vfj  
bDownOver = true; $i@5'[jA  
//nPos = fileAccessI.write (b,0,nRead); ?|^1-5l3  
} ;D]TPBE  
catch(Exception e){e.printStackTrace ();} yoV"?W>!  
} GMOv$Tn-_L  
} {U=za1Ga  
uXeBOLC  
j^ZpBNL  
//打印回应的头信息 yB}y'5  
public void logResponseHead(HttpURLConnection con) R4}G@&Q  
{ A"eT@  
for(int i=1;;i++) +XWXHt  
{ L.!:nu]
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String header=con.getHeaderFieldKey(i); vE?qF9I{$0  
if(header!=null) ?Z!itB~  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); oq]KOj[  
Utility.log(header+" : "+con.getHeaderField(header)); gzzPPd,hd  
else c#9 zw[y-L  
break; ^f!d8 V  
} &nPv%P,e  
} =KT7ZSTV  
O\OG~`HBN  
:[(X!eP  
public void splitterStop() ika{>hbH  
{ >~J_9'gX6
 
bStop = true; 4)9X) Qx  
} a|?CC/Ra  
. 36'=K  
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} ?vf{v  
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/* y9\s[}c_  
**FileAccess.java 1aYO:ZPy  
*//文件访问(定位，写) :'GTCo$3  
package NetFox; Kr]!B
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import java.io.*;
=sG(l  
3 ;.{ O%bX  
BY,%+>bc)  
public class FileAccessI implements Serializable{ 
1[3"|  
vR1%&(f{  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 zZ-e2)1v  
RandomAccessFile oSavedFile; 9FV#@uA}D  
long nPos; #D//oL"u]  
dJNYuTZ'  
o?{VGJH<v  
public FileAccessI() throws IOException >&?wo{b  
{ [4xN:i  
this("",0); WKxJ`r\  
} QS=n 50T,  
?WUE+(oH>  
`j=CzZ*em?  
public FileAccessI(String sName,long nPos) throws IOException C<w9f  
{ +$},Hu69j  
oSavedFile = new RandomAccessFile(sName,"rw"); " I`YJEv  
this.nPos = nPos; _Zf1=&U#/  
oSavedFile.seek(nPos); 8Yq6I>@!  
} 1ygu>sKS&A  
m U7Ad"  
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public synchronized int write(byte[] b,int nStart,int nLen) HEe0dqG  
{ nk-6W4  
int n = -1; eMz,DYa/G  
try{ MzK&Jh  
oSavedFile.write(b,nStart,nLen); Vg[U4,  
n = nLen; `q_7rrkO  
} RSmxwx^  
catch(IOException e) MiOSSl};  
{ zi*D8!_C  
e.printStackTrace (); e4CG=K3s  
} L4kYF~G:4  
r="X\ [on  
5+3Z?|b  
return n; ?wwY8e?S  
} fXL>L   

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h!  
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} PVEEKKJP]J  
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} A#C  
/* 2~]c`/M3  
**SiteInfoBean.java e`}|*^-  
*/ v/yk T9@;  
package NetFox; /.WD'*H  
gn(n</\/O  
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public class SiteInfoBean { Nt/*VYUn  
HM[BFF[;/  
kFk+TXLDIt  
private String sSiteURL; //Site's URL O~aS&g/sf  
private String sFilePath; //Saved File's Path &a:>P>\  
private String sFileName; //Saved File's Name nh9K(  
private int nSplitter; //Count of Splited Downloading File  pd X9G  
dwx1EdJ{  
9,,v0tE  
public SiteInfoBean() TvdmgVNP  
{//nSplitter的缺省值为5 .Uih|h  
//default value of nSplitter is 5 >656if O  
this("","","",5); o_G.J4 V  
} 'w9tZO\2  
',
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 89 (k<m  
{ 5gJQr%pS  
sSiteURL= sURL; SH}O?d\Q:  
sFilePath = sPath; Y}f%/vus  
sFileName = sName; U_I'Nz!^t  
this.nSplitter = nSpiltter; CB|z{(&N  
FP9ZOoog  
]i$CE|~  
} J::SFu=  
>/'WU79TYE  
`C!Pe84(  
public String getSSiteURL() @69q// #B  
{ T@Q.m.iV4  
return sSiteURL; $V\xN(Ed  
} BwBv'p+n  
.)W8 U [  
DDkOg]  
public void setSSiteURL(String value) MCYrsgg}  
{ 45-pJf8F  
sSiteURL = value; /-4%ug tD$  
} O>k.sO <  
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public String getSFilePath() 'x6Mqv1W  
{ "ht2X w  
return sFilePath; 7x1jpQ-  
} e94csTh=  
aX  ?ON
 
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public void setSFilePath(String value) H3b@;&`&  
{ $!fz87-p>  
sFilePath = value; J\ 3~  
} +w}5-8mH&>  
% mIq,  
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public String getSFileName() ]
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{ ^|gN?:fA}  
return sFileName; 4s$))x9p  
} da2BQ;  
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g\jdR_/  
public void setSFileName(String value) >eU;lru2Q  
{ XVI+Y  
sFileName = value;
XE>XzsnC  
} +$<m;@mZ  
*?i~AXJm  
h"<r
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public int getNSplitter() *np%67=jO  
{ 12rr:(#%s  
return nSplitter; @w|~:>/g  
} k
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#U6Wv1H{Lp  
;>Kxl}+R  
public void setNSplitter(int nCount) *.~M#M 9c  
{ :z^c<KFX  
nSplitter = nCount; KD#ip3  
} \GPWC}V\s  
} m$$U%=r>@  
naAZR*(A  
2j_L jY'7  
/* A).wjd(_,  
**Utility.java (F#Qunze  
*/ :KW   
package NetFox; vmk c]DC  
^srx/6X  
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public class Utility { WMYvE\"  
M'[J0*ip  
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public Utility() h],_1!0  
{ ==Y^~ab;K  
i #8)ad  
"S6d^  
} 1 "4AS_Q  
2.2 s>?\  
//线程睡眠 |qZ4h
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public static void sleep(int nSecond) Aw >DZ2  
{ 'Z;R!@Dm  
try{ U?.VY@  
Thread.sleep(nSecond); '{C=vW  
} `qUmOFl  
catch(Exception e) `A?/Ww>;  
{ Plt~l3_  
e.printStackTrace (); SVeL c  
} LnM+,cBz  
} E*k=8$Y  
G0<m3 Up  
//日志 CbwQ'c$}  
public static void log(String sMsg) C~kw{g+|  
{ !v$hqNt7  
System.err.println(sMsg); Z(CzU{7c  
} V>z8*28S.  
ky[FNgQ3n  
P PmE.%_  
public static void log(int sMsg) {:!*1L  
{ _d,_&
7  
System.err.println(sMsg); nww,y  
} y/ vE  
} a^|mF# z  
ld}-}W-cq  
O-
q [#P  
/* i]YH"t8GY  
**TestMethod.java ^|OxlfS  
*/ !.kj-==s{7  
package NetFox; &Q 3!ty  
"y#$| TMB  
l8jm7@.E  
public class TestMethod { JrS|Ib)6  
4fQ<A <2/  
`Y8
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public TestMethod() q,kdr)-  
{ ///xx/weblogic60b2_win.exe /2WGo-  
try{ ,uK }$l  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); $M#G;W
5c  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); {ge^&l  
SiteFileFetch fileFetch = new SiteFileFetch(bean); O &;Cca
 
fileFetch.start(); Un@dWf6'  
} A"d=,?yE  
catch(Exception e){e.printStackTrace ();} $,F1E VJ  
7'CdDB6&.  
E%2]c?N5  
} V+-%$-w>  
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public static void main(String[] args) g2BE-0,R  
{ RQ!kVM@  
new TestMethod(); =J<3B H^m  
} c7,p5[  
} Qne@Vf kA  
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