http断点续传简单实现（java)

/* hO$Gx*e$  
**SiteFileFetch.java +`Q]p"G  
*/ JRz)A4P  
package NetFox; 2@Yu:|d4U  
import java.io.*; >v@3]a i  
import java.net.*; 1T|")D  
`B3-#!2X  
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public class SiteFileFetch extends Thread { d"?"(Q_8n  
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SiteInfoBean siteInfoBean = null; //文件信息Bean myX&Z F_9  
long[] nStartPos; //开始位置 9Jh&C5\\  
long[] nEndPos; //结束位置
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FileSplitterFetch[] fileSplitterFetch; //子线程对象 ?sdSi--  
long nFileLength; //文件长度 tDL.+6/  
boolean bFirst = true; //是否第一次取文件 fK=0?]s}I  
boolean bStop = false; //停止标志 qypF}Pw  
File tmpFile; //文件下载的临时信息 *s 4Ym
  
DataOutputStream output; //输出到文件的输出流 zuN(~>YH  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） AYY(<b  
public SiteFileFetch(SiteInfoBean bean) throws IOException | 8mWR=9fs  
{ akr2Os  
siteInfoBean = bean; :]F66dh+  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); WcSvw  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); \K\eq>@6  
if(tmpFile.exists ()) R7(XDX=[s  
{ &PV%=/-J  
bFirst = false; "$(D7yFO  
read_nPos(); tL;.vR
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} ;yNY/  
else v]on0Pi!  
{ .-HM{6
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nStartPos = new long[bean.getNSplitter()]; iYT?6Y|+  
nEndPos = new long[bean.getNSplitter()]; )tJaw#Mih  
} Ln&~t(7  
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s) s9Z,HY  
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} qB_s<cpn>  
H[?S*/n,<  
[>
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public void run() ``g  
{ X);'[/]E*  
//获得文件长度 >>J$`0kM*  
//分割文件 ,}W|cm>  
//实例FileSplitterFetch rWJ5C\R  
//启动FileSplitterFetch线程 o?/H<k\5
  
//等待子线程返回 {jYVA~.|Z  
try{ B<BS^waU  
if(bFirst) 0/DO"pnL@  
{ Ng;?hTw  
nFileLength = getFileSize(); ~Sb)i f  
if(nFileLength == -1) g#74c'+  
{ REU&8J@k&?  
System.err.println("File Length is not known!"); fWA#n  
} >F7HKwg}Z  
else if(nFileLength == -2) H%l-@::+$  
{ iNkN'("  
System.err.println("File is not access!");  ~ e?af  
} QlB9m2XB  
else G|nBja8vm  
{ ]}'bRq*]  
for(int i=0;i<nStartPos.length;i++) ,S dj"C  
{ 6e\?%,H  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); u0+F2+ I  
} L;*7p9  
for(int i=0;i<nEndPos.length-1;i++) [[T6X9  
{ kdGq\k,  
nEndPos = nStartPos[i+1]; \41/84BA  
} .9ZK@xM&?  
nEndPos[nEndPos.length-1] = nFileLength; L /
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} c0e[vrP:  
} +`"Tn`O  
|) ~-Wy  
aTm R~k  
//启动子线程 ML|?H1m>  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; tQNc+>7k+u  
for(int i=0;i<nStartPos.length;i++) 9C?SEbC  
{ ?;UR9f|!  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), QhRz57'  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 'C7R* P  
nStartPos,nEndPos,i); aO}hE2]  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); <L8FI78[*  
fileSplitterFetch.start(); O{3X`xAf  
} ]Kjt@F";  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), J?#vL
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 7wWx8  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 5V(#nz  
nEndPos = " + nFileLength); LFi{Q{E)  
// fileSplitterFetch[nPos.length-1].start(); <f:(nGj  
-J6`  
V[%IU'{:  
//等待子线程结束 6`'g ${U  
//int count = 0; Q'^'G>MBJ  
//是否结束while循环 aJ=)5%$6kc  
boolean breakWhile = false; q
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l v:GiA"X  
CIo`;jt
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while(!bStop) LrO[l0#'Q  
{ 8q]"CFpa  
write_nPos(); aU
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Utility.sleep(500); rkWy3X{%2<  
breakWhile = true; 7]?y _%kT  
C[Q4OAFG  
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for(int i=0;i<nStartPos.length;i++) F> Ika=z,  
{ eV(.\Lj  
if(!fileSplitterFetch.bDownOver) =os!^{p7>  
{ JDa_;bqL  
breakWhile = false; P
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break; E[ -yfP~[  
} C%<Dq0j  
} OB=bRLd.IR  
if(breakWhile) pheu48/f  
break; 1Ci^e7
|?  
]
QY-LO(  
6||%T$_;}  
//count++; C[TjcHoA  
//if(count>4) c^H#[<6p  
// siteStop(); f:P;_/cJc  
} x{!+4W;S  
v h)CB8  
$_'<kH-eP  
System.err.println("文件下载结束！"); ncUhCp?'  
} so.}WU  
catch(Exception e){e.printStackTrace ();} 9k62_]w@6  
} 9i_@3OVl  
IY!.j5q8  
>2K'!@~'  
//获得文件长度 3zfpFgD!  
public long getFileSize() Lfa&JKd  
{ p;o"i_!  
int nFileLength = -1; &'PLOyWw  
try{ L?a4>uVY  
URL url = new URL(siteInfoBean.getSSiteURL()); 2\64~a^  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection ();

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httpConnection.setRequestProperty("User-Agent","NetFox"); Y@UW\d*'%I  
&09~ D8f'  
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int responseCode=httpConnection.getResponseCode(); 46l*ui_  
if(responseCode>=400) gL| 9hvHr[  
{ 01 +#2~S  
processErrorCode(responseCode); 8(NS;?  
return -2; //-2 represent access is error =kq<J-:#R  
} beYGP  
wS$ 'gKA6  
{EoZ}I  
String sHeader; )9/i
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%(%EEt  
AYoTCi%7E  
for(int i=1;;i++) "\~>[on  
{ M`=\ijUwN  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Fm&f  
//Utility.log(in.readLine()); '>bn94$  
sHeader=httpConnection.getHeaderFieldKey(i); F|VHr
@%  
if(sHeader!=null) i 28TH Jh  
{ !3c+}j-j  
if(sHeader.equals("Content-Length")) v?nGAn  
{ %,S:^Rvv  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader));
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break; F!I9)PSj  
} (?T{^Hg  
} 3-;<G  
else SFP?ND+7  
break; . Z9c.E{  
} $i3`cX)g  
} bFA lC  
catch(IOException e){e.printStackTrace ();} y~t e!C  
catch(Exception e){e.printStackTrace ();} "f3mi[  
f@Ve,i  
h{~GzrL*  
Utility.log(nFileLength); NN:zQ_RT  
2=7[r-*E  
:c}PW"0v  
return nFileLength; h6`VU`pPI  
} \Yv44*I`  
md9JvbB  
4/SltWU  
//保存下载信息（文件指针位置） E.*wNah"U  
private void write_nPos() V^;lg[:  
{ W8]?dL}|  
try{ Qe9}%k6@E  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 7<8'7<X  
output.writeInt(nStartPos.length); j\BtaC  
for(int i=0;i<nStartPos.length;i++) `X&d:!}F  
{ -@'RYY=  
// output.writeLong(nPos); %vG;'_gMB  
output.writeLong(fileSplitterFetch.nStartPos); D iHj!tZN  
output.writeLong(fileSplitterFetch.nEndPos); )iPU  
} U~zy;MT  
output.close(); .v=n-k7  
} ZWB3R  
catch(IOException e){e.printStackTrace ();} 8_rd1:t5  
catch(Exception e){e.printStackTrace ();} eq2LV=d{m  
} .o<9[d"  
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YAi@EvzCVy  
//读取保存的下载信息（文件指针位置） 9(a*0H  
private void read_nPos() Q"LlBp>t|#  
{ MpJ3*$Dr  
try{ E%f!SD  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); $S/WAw,/  
int nCount = input.readInt(); C}o^p"M*B3  
nStartPos = new long[nCount]; b!EqYT  
nEndPos = new long[nCount]; 0*uJS`se6Z  
for(int i=0;i<nStartPos.length;i++) -)ri,v{:c  
{ ']X0g{%  
nStartPos = input.readLong(); '
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nEndPos = input.readLong(); bg|=)sw4  
} \w$e|[~  
input.close(); ${t$:0R,h  
} ]jmZ5h#[  
catch(IOException e){e.printStackTrace ();} _Mh..#)`[  
catch(Exception e){e.printStackTrace ();} =k!F`H`/%'  
} uE#i3( J  
8rz,MsFR  
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private void processErrorCode(int nErrorCode) D/2;b;-  
{ u<+RA  
System.err.println("Error Code : " + nErrorCode); yzGBGC  
} .+ic6  
d5W=?  
$M4C4_oPy  
//停止文件下载 uy=<n5`oNG  
public void siteStop() #D+.z)iZn  
{ ?/Aql_?3  
bStop = true; DxP65wU  
for(int i=0;i<nStartPos.length;i++) $*9:a3>zny  
fileSplitterFetch.splitterStop(); K}LF ${bS  
. Eb=KG  
LA,G>#?H  
} Q#4OgNt  
} eoiC.$~\  
//负责部分文件的抓取 /cD]m  
**FileSplitterFetch.java bde6 ;=oM  
*/ Y$ZDJNz  
package NetFox; m?1AgsBR  
uKT\\1Jrq  
aQ1n1OBr  
import java.io.*; \AD|;tA\vE  
import java.net.*; Q(hAV  
~?lmkfy  
OZl0I#@A  
public class FileSplitterFetch extends Thread { &y2DI"Ff  
x Sv@K5"8!  
UzkX;UA  
String sURL; //File URL l_&T)Ei  
long nStartPos; //File Snippet Start Position xl@  
long nEndPos; //File Snippet End Position ~</H>Jd  
int nThreadID; //Thread's ID <QK2Wc_}-"  
boolean bDownOver = false; //Downing is over 4e|(= W`  
boolean bStop = false; //Stop identical w 1O)  
FileAccessI fileAccessI = null; //File Access interface yjChnp Cc  
pH?"@  
m8v=pab e  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException #X<s_.7DJ  
{ )-LSn  
this.sURL = sURL; ZV:0:k.x  
this.nStartPos = nStart; 9q<?
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this.nEndPos = nEnd; pH.&OW%  
nThreadID = id; I}/-zyx>=  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Zu^J X/um  
} EMS$?"K  
ARid   
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public void run()
7t/C:2^&  
{ onUF@3V  
while(nStartPos < nEndPos && !bStop) 0^ $6U  
{ F:2V;  
4--[.j*W  
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try{ H|B4.z  
URL url = new URL(sURL); :YN,cId*  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); h4? 'd+
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httpConnection.setRequestProperty("User-Agent","NetFox"); 6\/(TW&  
String sProperty = "bytes="+nStartPos+"-"; &28%~&L  
httpConnection.setRequestProperty("RANGE",sProperty); 2-u9%  
Utility.log(sProperty); f(*^zga,  
'uF"O"*  
;jT@eBJ  
InputStream input = httpConnection.getInputStream(); B#x.4~YX  
//logResponseHead(httpConnection); " [K>faV  
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byte[] b = new byte[1024]; :+}Eo9  
int nRead; Jg%jmI;Y  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) kT4Tb%7KM  
{ Qw/H7fvh&  
nStartPos += fileAccessI.write(b,0,nRead); Q2!vO4!<N  
//if(nThreadID == 1) |jyoT%SQ  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); sJ)Pj?"\?  
} p3{ 3[fDx  
Q.L.B7'e7  
z] teQaUZ  
Utility.log("Thread " + nThreadID + " is over!"); Z"'tJ3Y.~  
bDownOver = true; LO M-i>  
//nPos = fileAccessI.write (b,0,nRead); c{K[bppJ*  
} y[sO0u\  
catch(Exception e){e.printStackTrace ();} 8Ir = @  
} [cf!%3>53  
} I>z0)pB  
#x5?RHX56  
5KDN8pJN  
//打印回应的头信息 "\M^jO  
public void logResponseHead(HttpURLConnection con) S-KHot ?  
{ >-Q=o,cl%3  
for(int i=1;;i++) $n@B:kv5p  
{ L)j<;{J/Q0  
String header=con.getHeaderFieldKey(i); MFm2p?zPm  
if(header!=null) !%%(o%bi~  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); K-drN)o  
Utility.log(header+" : "+con.getHeaderField(header)); +OC~y:  
else \L{V|}"X  
break; q<Zza  
} k'JfXrW<!  
} =-|,v*  
|jE0H!j  
8P3"$2q  
public void splitterStop() 5]yby"Z?}  
{ whvvc2  
bStop = true; eUE(vn#  
} '?MT"G  
$^j#z^7  
/L?
ia  
} rRzc"W}K+  
OtFGo8  
&i
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/* zsuXN*
 
**FileAccess.java wW+@3bPl  
*//文件访问(定位，写) $z5  
package NetFox; eJwHeG  
import java.io.*; }:a:E~5y  
8[xl3=  
1A.ecv'  
public class FileAccessI implements Serializable{ I&G"{Dl94  
?."YP[;  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 mJL=H
  
RandomAccessFile oSavedFile; |QB[f*y5  
long nPos; !U8n=A#,-  
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24Uvi:B?~  
public FileAccessI() throws IOException 5|0}   
{ UCVdR<<Z  
this("",0); ==)q{e5  
} Yb;$z'  
jM!Q 04(  
3r-oZ8/n  
public FileAccessI(String sName,long nPos) throws IOException $;%k:&\f  
{ Th>ff)~e  
oSavedFile = new RandomAccessFile(sName,"rw"); 8%Hc%T[RnT  
this.nPos = nPos; lLi)?  
oSavedFile.seek(nPos); K)[DA*W  
} %{HeXe  
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8*Ke;X~N  
public synchronized int write(byte[] b,int nStart,int nLen) Vx*O^cM  
{ ].r~?9'/  
int n = -1; {IA3`y~  
try{ ::R5F4  
oSavedFile.write(b,nStart,nLen); \qj(`0HG  
n = nLen; e'0BP,\f_}  
} |Pj]sh[^Y  
catch(IOException e) AD^Q`7K?uR  
{ !$L~/<&0g  
e.printStackTrace (); FH7h?!|t  
} Cu&y',ee~  
zVyMmw\  
-"~XI~a@Wo  
return n; {7Q)2NC  
} b:t|9FE%  
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yHYK,3/C,  
} YgL{*XYAt  
eNc>^:&y*  
^2)<H7p  
/*
xh|<`>5  
**SiteInfoBean.java &UfP8GE9  
*/ RBOg;EJ  
package NetFox; iV2v<ap.n  
!\Vc#dslt  
&\$~  
public class SiteInfoBean { g?E8zf `  
F0x'^Z}Q;  
7*\CfqrU  
private String sSiteURL; //Site's URL n5>OZ
3 E@  
private String sFilePath; //Saved File's Path HP2J`>oo  
private String sFileName; //Saved File's Name c.4WwzK  
private int nSplitter; //Count of Splited Downloading File IF'Tj`yD  
o'J^kd`  
*!m(oP  
public SiteInfoBean() v@ifB I  
{//nSplitter的缺省值为5 JpE7"Z"~MS  
//default value of nSplitter is 5 hAU@}"=G  
this("","","",5); 34<k)0sO  
} y/>IF|aX  
\zLKSJ]  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) nAaY5s0D  
{ xVN(It7g  
sSiteURL= sURL; buKSZ  
sFilePath = sPath; ]e6$ ={  
sFileName = sName; Q4Z
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this.nSplitter = nSpiltter;
8@,8j!$8G  
s((c@)M  
GUn$IPOM  
} B]u!BBjC  
,{2= nb[  
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public String getSSiteURL() sWv!ig_  
{ keb.%cb=  
return sSiteURL; 9 iV_  
} V `7(75  
OF/hD2V  
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public void setSSiteURL(String value) &oxHVZJ  
{ wA\a ]X.  
sSiteURL = value; D6,Ol4d  
} k
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/tj_WO_  
bXi(]5  
public String getSFilePath() suHi
sc*  
{ @Nn'G{8OG  
return sFilePath; %>-?oor  
} =z zmz7op  
`Z^\<{z  
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public void setSFilePath(String value) BU.O[?@64  
{ :!yPR  
sFilePath = value; ~s*kuj'%+  
} &}r-C97  
qs{wrem  
d<RJH  
public String getSFileName() w@WPp0mny  
{ Fv<3VKueK[  
return sFileName; _N:GZLG  
} UM2yv6:/  
<w3_EO  
!v. <H]s)  
public void setSFileName(String value) lYT_Y.%I  
{ MY'T%_id  
sFileName = value;  kMZo7 y  
} I%l2_hs0V  
x>tsI}C  
-ImVXy]?  
public int getNSplitter() YI>9C 76L  
{ e$7KMH=  
return nSplitter; W`uq,r0Xsy  
} %UlgG1?A  
35JVF*z  
CbwQbJ/v7  
public void setNSplitter(int nCount) Pk>S;KT.  
{ i0F6eqe=J  
nSplitter = nCount; 1`GW>ZKv  
} DE+k'8\T  
} UCj{ &  
fp}5QUm-  
57KrDxE}  
/* yz"hU  
**Utility.java YC(X= D  
*/ qM<CBcON  
package NetFox; 
.
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YJ|U|[
 
\5}*;O@  
public class Utility { _2hZGC%&E  
@z^7*#vQv  
~G1B}c]  
public Utility() ~OWpk)Vq  
{ |K" nSXzk  
DMOP*;Uk  
UF$O@l  
} "7eL&  
7AlL,&+  
//线程睡眠 qh+&Zx~  
public static void sleep(int nSecond) EQ.K+d*K][  
{ P *&Cght>0  
try{ l6zYiM  
Thread.sleep(nSecond); 1Tr%lO5?6  
} =RAojoN  
catch(Exception e) ^B1$|C D,  
{ >pp#>{}  
e.printStackTrace (); NFF!g]QN  
} Z/T(
4  
} tSe[*V4{'  
XRHngW_A  
//日志 uPxJwWXO  
public static void log(String sMsg) `{m,&[n  
{ %j/pln&  
System.err.println(sMsg); ~~=]_lwyK%  
} eV~"T2!Sb  
%CrTO(  
Bw
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public static void log(int sMsg) n5z|@I`S_  
{ 5WvsS( 9H  
System.err.println(sMsg); )7
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} ^#IE t#  
} Wt=\hixj-  
|AT`(71  
K>C@oE[W  
/* 0Y:)$h2?  
**TestMethod.java $ w+.-Tr  
*/ =sAU5Ag68  
package NetFox; Z*ag{N  
r`\@Fv,&#  
=k>fW7e  
public class TestMethod { m41%?uC/  
TV#>x!5!d  
TY%=Y=  
public TestMethod() B3pjli  
{ ///xx/weblogic60b2_win.exe _zJ /z  
try{ _90<*{bt.  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); `<kB/T  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); O8cZl1C3  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ANgt\8  
fileFetch.start(); P)#h4|xZ  
} n/x((d%"E  
catch(Exception e){e.printStackTrace ();} /='Q-`?9  
81C;D`!K  
M6bM`wHH>  
} {3.n!7+  
CRD=7\0(D+  
Ql%B=vgKL  
public static void main(String[] args) UNK.39  
{ jgS
3#  
new TestMethod(); ANJL8t-m  
} tfu`_6  
} ! ,{zDMA  
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