http断点续传简单实现（java)

/* bG^E]
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**SiteFileFetch.java KB&t31aq  
*/ xHJ+!   
package NetFox; /6gqpzum4  
import java.io.*; )KaQ\WJ:  
import java.net.*; Zu$f-_"  
/!eC;qp;[  
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public class SiteFileFetch extends Thread { 59$mfW o>  
7_E+y$i=  
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SiteInfoBean siteInfoBean = null; //文件信息Bean HMgZ&
v  
long[] nStartPos; //开始位置 ?qHW"0Tjn  
long[] nEndPos; //结束位置 _R8)%<E  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 lk}R#n$  
long nFileLength; //文件长度 'iXjt MX  
boolean bFirst = true; //是否第一次取文件 Mn7 y@/1  
boolean bStop = false; //停止标志 wI #_r_  
File tmpFile; //文件下载的临时信息 z/F(z*'v  
DataOutputStream output; //输出到文件的输出流 QD+dP nZu  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 2(5wFc  
public SiteFileFetch(SiteInfoBean bean) throws IOException `2J6Dz"W  
{ `;hsOfo  
siteInfoBean = bean; oE"!  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); n1y#gC  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); r7C m  
if(tmpFile.exists ()) yHCQY4/  
{ G+m|A*[>  
bFirst = false; UB
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FX  
read_nPos(); h[C!cX  
} yf3%g\k  
else {Ylj]  
{ 9H1R0iWW  
nStartPos = new long[bean.getNSplitter()]; \r324Bw>2  
nEndPos = new long[bean.getNSplitter()]; k1$|vzMh  
} <Sm=,Sw  
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} V F6OC4 K  
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public void run() 42Gr0+Mb  
{ qoB  
//获得文件长度 O*H:CW  
//分割文件 MZ=U} &F  
//实例FileSplitterFetch }UXj|SY  
//启动FileSplitterFetch线程 0Ny0#;P  
//等待子线程返回 ;?=nr5;q  
try{ RNRMw;cT  
if(bFirst) /B|#GJ\\3  
{ >]T(}S~  
nFileLength = getFileSize(); WE|L{  
if(nFileLength == -1) :&6QKTX  
{ `Wn0v2@a(~  
System.err.println("File Length is not known!"); g}ciG!0  
} Hi,_qlc+  
else if(nFileLength == -2) K?-K<3]9f  
{ p|(910OEQ  
System.err.println("File is not access!"); /:ma}qGy  
} qAR~js`5  
else rU<  H7U  
{ Z:O24{ro
5  
for(int i=0;i<nStartPos.length;i++) >^|\wy  
{ M`BD]{tN}  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ^=OjsN

 
} r5lp<md  
for(int i=0;i<nEndPos.length-1;i++) Z>o;Yf[  
{ gWy2$)  
nEndPos = nStartPos[i+1]; eK/[jxNO  
} $'L(}gNv5  
nEndPos[nEndPos.length-1] = nFileLength; #q==GT7  
} wMt?yc:X  
} (LL4V 3)  
\
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[p}J=1S  
//启动子线程 \{{B57/Isq  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 0J@)?,V-.  
for(int i=0;i<nStartPos.length;i++) i&mu=J[  
{ pA(@gisg  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), N(t1?R/e
,  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), vq(@B  
nStartPos,nEndPos,i); Z(/jQ=ozQ  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); P~ffgzP  
fileSplitterFetch.start(); ll[U-v{  
} ^uIZs}=+  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), "JJ )w0  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); lsJ'dS  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", sb4r\[?  
nEndPos = " + nFileLength); :'1ePq  
// fileSplitterFetch[nPos.length-1].start(); oIoJBn  
Wf0ui1@  
#`y7L4V*o  
//等待子线程结束 .H7"nt^  
//int count = 0; {r[*}Bv  
//是否结束while循环 PovPO  
boolean breakWhile = false; :V}8a!3h  
=]-!  
<gf:QX!  
while(!bStop) r^WO$u|@i  
{
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write_nPos(); *|_u~v:)|5  
Utility.sleep(500); >,uof?  
breakWhile = true; 1ww|km  
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s) V7$D  
for(int i=0;i<nStartPos.length;i++) k5g\s9n]  
{ CM9+h;Zm  
if(!fileSplitterFetch.bDownOver) ;[gv-H  
{ 1MfRFv  
breakWhile = false; #vLDNR  
break; t8]u#bx"?  
} 4?jhZLBU  
} HmbTV(lC  
if(breakWhile) 6$fC R  
break; 'qQDM_+  
wqA5GK>m2  
]$0{PBndW  
//count++; 1PLKcU  
//if(count>4) [OH>NpL  
// siteStop(); 2/B(T5PY@  
} d@,q6R}!MP  
]
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|06J4H~k  
System.err.println("文件下载结束！"); %b@>riR(y  
} rAP+nh ans  
catch(Exception e){e.printStackTrace ();} >4LX!^V"  
} -s:JD
J*  
5jx{O${u  
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//获得文件长度 6K?+adKlc  
public long getFileSize() YJrK oK}  
{ m='+->O*'l  
int nFileLength = -1; FCqs'  
try{ {'>X6:  
URL url = new URL(siteInfoBean.getSSiteURL()); GN=F-*2  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); `n5RDz/f0  
httpConnection.setRequestProperty("User-Agent","NetFox"); "=4=Q\0PT  
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"TN}=^A\F  
int responseCode=httpConnection.getResponseCode(); >6jyd{  
if(responseCode>=400) r)U9u 0  
{ HV>|f'45  
processErrorCode(responseCode); ks(PH6:]<  
return -2; //-2 represent access is error kE6\G}zj  
} 1DZ
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DU}q4u@)  
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String sHeader; b-~`A;pr  
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for(int i=1;;i++) .JQR5R |Q  
{ b!7"drge:  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 8&dmH&  
//Utility.log(in.readLine()); N_/&xHw  
sHeader=httpConnection.getHeaderFieldKey(i); :Tj,;0#/  
if(sHeader!=null) Ai#W. n  
{ .z+QyNc:  
if(sHeader.equals("Content-Length")) EWH'x$z_q  
{ joM98H@  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); g*Cs/w  
break; ;]<$p[m  
} 9H.E15B  
} sjShm  
else Z~$&
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break; LR9dQ=fHS  
} .lTGFeJqZ4  
} QKCk. 0Xe  
catch(IOException e){e.printStackTrace ();} -R6z/P(}  
catch(Exception e){e.printStackTrace ();} 9D8el}uHf  
8V~w3ssz  
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Utility.log(nFileLength); )O2^?Q quS  
<
7^_M*F9  
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return nFileLength; siyJjE)}w  
} }\l5|Ft[!  
`[o^w(l:5@  
;=UrIA@y;=  
//保存下载信息（文件指针位置） ~rn82an@G  
private void write_nPos() 8?
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{ Fnll&TF  
try{ Z
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output = new DataOutputStream(new FileOutputStream(tmpFile)); #kma)_X  
output.writeInt(nStartPos.length); -Frx{3  
for(int i=0;i<nStartPos.length;i++) NUx%zY  
{ o{zo-:>Jp  
// output.writeLong(nPos); q/%f2U%4:  
output.writeLong(fileSplitterFetch.nStartPos); 6aMqU?-
 
output.writeLong(fileSplitterFetch.nEndPos); 7i6-Hq  
} h-jea1m  
output.close(); hnG'L*HooE  
} $!KV]]  
catch(IOException e){e.printStackTrace ();} m_(+-G
  
catch(Exception e){e.printStackTrace ();} ULQ*cW&;?  
} jQsucs5$h  
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//读取保存的下载信息（文件指针位置） !:e}d+F  
private void read_nPos() atW;S99#  
{
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try{ B6=8cf"i  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); '+'
  
int nCount = input.readInt(); Ibpk\a
?A{  
nStartPos = new long[nCount]; |\N[EM%.@  
nEndPos = new long[nCount]; 6!b96bV  
for(int i=0;i<nStartPos.length;i++) l'-iIbKX  
{ LFg<j1Gk`  
nStartPos = input.readLong(); $IB@|n  
nEndPos = input.readLong(); e&]XiV'  
} E: XzX Fxx  
input.close(); <7)Vj*VxC  
} JUwP<C[  
catch(IOException e){e.printStackTrace ();} )t@OHSl  
catch(Exception e){e.printStackTrace ();} p~=%CG^5  
} Kw925@W  
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private void processErrorCode(int nErrorCode) fN
t  
{ 1Pn!{ bU3@  
System.err.println("Error Code : " + nErrorCode); i,* DWD+  
} \<;/)!Nmw  
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inR8m 4c]P  
//停止文件下载 % J+'7'g  
public void siteStop() 80:na7$)#  
{ ap_(/W  
bStop = true; I>ofSaN  
for(int i=0;i<nStartPos.length;i++) qYbod+U
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fileSplitterFetch.splitterStop(); V3F2
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} I /> .P  
} c$1ez  
//负责部分文件的抓取 Qv']*C[!z  
**FileSplitterFetch.java {e>}.R  
*/ }ZR3  
package NetFox; 97<Y. 0  
<3ovCqa  
LTFA2X&E=  
import java.io.*; /z5j.TMs  
import java.net.*; #J1a `}x  
C2DNyMu  
cBc6*%ZD  
public class FileSplitterFetch extends Thread { H:p(C?tk{  
H|75,!<  
-OVJ]  
String sURL; //File URL #YjV3O5<  
long nStartPos; //File Snippet Start Position 9u"im+=:  
long nEndPos; //File Snippet End Position ZLo3 0*  
int nThreadID; //Thread's ID rpy`Wz/[  
boolean bDownOver = false; //Downing is over I"Y?vj9]  
boolean bStop = false; //Stop identical ?Y
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FileAccessI fileAccessI = null; //File Access interface ;jI\MZ~l\  
o$Hc5W([Z  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Ntg#-_]  
{ #N,\c@Gy  
this.sURL = sURL; {s_0[>  
this.nStartPos = nStart; n |.- :Zy  
this.nEndPos = nEnd; :n>:*e@w%  
nThreadID = id; $c  f?`k  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ?CM,k0  
} .hZ =8y9  
%xWmzdn  
vT3LhN+1  
public void run() *1%=?:$(r6  
{ bNIT 1'v  
while(nStartPos < nEndPos && !bStop) b\H(Lq17  
{ 213D{#2  
[xM07%:  
 Zp]Bs  
try{ 7Zr jU{  
URL url = new URL(sURL); 5F&i/8Ib  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); v }P~g  
httpConnection.setRequestProperty("User-Agent","NetFox"); EL~s90C  
String sProperty = "bytes="+nStartPos+"-"; @yobT,DXi  
httpConnection.setRequestProperty("RANGE",sProperty); h-!(O^M  
Utility.log(sProperty); &tp5y}=n  

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-YSn 3=  
InputStream input = httpConnection.getInputStream(); '_(oa<g  
//logResponseHead(httpConnection); VwtGHF'  
lWnV{/q\X  
1\zI#"b ^  
byte[] b = new byte[1024]; aU#8W.~  
int nRead; \U~ggg0h  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) =U|J{^ >I  
{ ls#O0  
nStartPos += fileAccessI.write(b,0,nRead); VAq(
t  
//if(nThreadID == 1) 9chiu%20  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 9x{T"'  
} LnR3C:NO k  
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Km\M/j|  
Utility.log("Thread " + nThreadID + " is over!"); X,T^(p  
bDownOver = true; y0A2{'w  
//nPos = fileAccessI.write (b,0,nRead); | b@?]M  
} ( B50~it  
catch(Exception e){e.printStackTrace ();} r!Mr\  
} /D)@y548~~  
} ,9W0fm\t  
YXD1B`23  
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R  
//打印回应的头信息 H
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public void logResponseHead(HttpURLConnection con) HJ_xg6.x  
{ #1m!,tC  
for(int i=1;;i++) `{tykYwCLc  
{ vuw1ycy)  
String header=con.getHeaderFieldKey(i); ts9N$?0:V  
if(header!=null) rV2}> k  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); gdkO|x  
Utility.log(header+" : "+con.getHeaderField(header)); 2.; OHQTE  
else j}h50*6KO  
break; mP:mzmUw  
} @6t3Us~/  
} $,6=.YuY  
=E |[8 U)  
CR, Y%0vQ  
public void splitterStop() gvwR16N  
{ +Pa!pj/< z  
bStop = true; F}.Af=<Q  
} y/kCzDT,  
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}
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/* $F/&/Aa  
**FileAccess.java `_<AZ{&&  
*//文件访问(定位，写) lXB_HDY  
package NetFox; XWB>' UDQ#  
import java.io.*; w)!(@}vd  
U*6-Y%7  
y`(z_5ClT  
public class FileAccessI implements Serializable{ jhg!K.A  
zIdQ^vm8Q  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 x/9`2X`~  
RandomAccessFile oSavedFile; ngdVRJL  
long nPos; qqkZbsN  
+mF}j=k  
kWoy%?|RRa  
public FileAccessI() throws IOException z<AQ;b  
{ SM^6+L"BE  
this("",0); 6qHo$#iT  
} x80~j(uVf  
<|m"Q!f  
[{Y$]3?}  
public FileAccessI(String sName,long nPos) throws IOException lezdJ  
{ <BO|.(ys  
oSavedFile = new RandomAccessFile(sName,"rw"); g5T~%t5lo  
this.nPos = nPos; x"N,
oDs  
oSavedFile.seek(nPos); if`/LJsa  
} 'nCBLc8  
XPY66VC&_  
#z5'5|3  
public synchronized int write(byte[] b,int nStart,int nLen) 3w^q0/GD  
{ H=wmN0s{<  
int n = -1; z:fd'NC  
try{ hl# 9a?  
oSavedFile.write(b,nStart,nLen); [IHT)%>E8&  
n = nLen; 8, WQ}cC  
} o>W}1_  
catch(IOException e) dXdU4YJX  
{ ^
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e.printStackTrace (); 9VP|a-  
} MKQa&Dvw  
\!631FcQ   
}K&K{ 9}  
return n; }7&;YAt  
} 3z5,4ps  
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qA03EU  
} !E$S&zVMQ  
!>2s5^JI9  
-`Z5#8P  
/* S"}FsS;k<?  
**SiteInfoBean.java #"f:m`  
*/ fTH?t_e  
package NetFox; 6?hv,^  
r]8B6iV  
U2SxRFs >  
public class SiteInfoBean { ~v<r\8`OI2  
wN*e6dOF  
@gTpiV2  
private String sSiteURL; //Site's URL 8LiRZ"  
private String sFilePath; //Saved File's Path VT+GmS  
private String sFileName; //Saved File's Name > m5j.GP;  
private int nSplitter; //Count of Splited Downloading File Gz6FwU8L  
Z\@vN[[  
-;Hd_ ~O>j  
public SiteInfoBean() op}x}Ioz  
{//nSplitter的缺省值为5 q>H!?zi\Hy  
//default value of nSplitter is 5 JfC.U,7Nc  
this("","","",5); LkNfcBa_  
} 8U=M.FFp  
;ATk?O4T  
5oORwOP  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) {;z3$/JB  
{ )Hw;{5p@  
sSiteURL= sURL; /V3*[  
sFilePath = sPath; ?(ks=rRK  
sFileName = sName; drN^-e  
this.nSplitter = nSpiltter; /i$&89yod  
Tm`QZh3  
&_!BMzp4  
} Pyk~V)~M  
N}s[0s  
%f, 9  
public String getSSiteURL() .F%!zaVIu  
{ jixU9]  
return sSiteURL; E{lq@it32p  
} [0_Kz"|  
/&ph-4\i  
} #%sI"9  
public void setSSiteURL(String value) ym1TGeFAq  
{ s31^9a  
sSiteURL = value; 0Z9jlwcQ  
} "hQV\|!\  
LscAsq<H<  
Sqfa,3?L  
public String getSFilePath() U>X06T  
{ ]4hXK!^Uu  
return sFilePath; 36lIV,YnU  
} mflI>J=g  
AV%Q5Mi}  
V+D"_  
public void setSFilePath(String value) d
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{
I]  
sFilePath = value; =U@*adgw  
} V
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u1nv'\*  
3ON]c13  
public String getSFileName() vqL{~tR  
{ SHwl^qVk[  
return sFileName; R[#5E|` `9  
} 0<i~XN0g  
%/UQ0d~b  
Q~*A`h#  
public void setSFileName(String value) XFBk:~}sI  
{ +>I4@1qC-|  
sFileName = value; ~2"
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} ',O@0L]L  
wmoOp;C  
DJ<e=F!  
public int getNSplitter() cHR}`U$  
{ f
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return nSplitter; /M'b137  
} <v{jJ7w  
7s[ ATu  
j^64:3  
public void setNSplitter(int nCount) r Ssv^W+  
{ X;}_[=-  
nSplitter = nCount; 1BWuFYB  
} s)To#  
} !`aodz*PO  
[s7I.rdGzz  
(/hF~A  
/* _Juhl^LM;  
**Utility.java 6 a$%  
*/ uAJ_`o[  
package NetFox; =jG3wf*  
b<[eBXe  
'
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public class Utility { pXQ&2s$  
AV8TP-Ls+  
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public Utility() Ni0lj:  
{ +bQn2PG=  
:;|x'[JoE?  
V];RQWs  
} ;eA~z"g  
$/d~bk@=l  
//线程睡眠 "Dy&`  
public static void sleep(int nSecond) Bq2}nDP  
{ vJcvyz#%1  
try{ 1w5p*U0 ;  
Thread.sleep(nSecond); $~9U-B\  
} d&U;rMEv  
catch(Exception e) w$t2Hd  
{ D@Wm-  
e.printStackTrace (); 1yKf=LZ^  
} @B[=`9KF[  
} :
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E3KPjK  
//日志 )lW<:?k  
public static void log(String sMsg) t71 0sWh{  
{ A&t}s #3  
System.err.println(sMsg); ,$G89jSM  
} #p[=iP
  
1`)R#$h  
7"S|GEs:  
public static void log(int sMsg) p<J/J.E  
{ RnTPU`  
System.err.println(sMsg); |X_yL3`Zb  
} {<|
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} '<@PgO~  
'uPqe.#?  
lOE
bh  
/* <Z0Tz6/j,  
**TestMethod.java xAoozDj  
*/ GN{.R7  
package NetFox; T8RQM1D_s  
N .SszZh  
Cvl"")ZZ`  
public class TestMethod { _mn4z+  
&XZ>}^lD^  
ciXAyT cG  
public TestMethod() ]w')~yk  
{ ///xx/weblogic60b2_win.exe [}VEDx
 
try{ "OWq]q#  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); F4:ssy^  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); WIbU^WJ0  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 3W27R  
fileFetch.start(); 1 8&^k|  
} LOOv8'%O8  
catch(Exception e){e.printStackTrace ();} !u=[/>  
_-h3>.;h9  
,0])]  
} v0HFW%YJ^J  
Ig=4Z*au!g  
R!-RSkB  
public static void main(String[] args) ,iHl;3bu  
{ T{ojla(  
new TestMethod(); mH8"k+k  
} }t-{,0  
} DsP+#PX  
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