http断点续传简单实现（java)

/* A#{I-*D[  
**SiteFileFetch.java z}iz~WZ  
*/ <>(v~a]  
package NetFox; tSY4'  
import java.io.*; \vx'+}  
import java.net.*; n^rbc;}  
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public class SiteFileFetch extends Thread { L
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SiteInfoBean siteInfoBean = null; //文件信息Bean elR1NhB|p  
long[] nStartPos; //开始位置 -]-0]*oAp  
long[] nEndPos; //结束位置 &> _aY
#  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 j+>[~c;0)  
long nFileLength; //文件长度 -tx%#(?wH  
boolean bFirst = true; //是否第一次取文件 I %sw(uoE  
boolean bStop = false; //停止标志 ~.6% %1?  
File tmpFile; //文件下载的临时信息 c}!`tBTm  
DataOutputStream output; //输出到文件的输出流 g6xQQ,q=l  
4=%,0.yt  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） {t4':{Y+  
public SiteFileFetch(SiteInfoBean bean) throws IOException O2"@09:  
{ xXnSo0`LF  
siteInfoBean = bean; (#x&Y#5  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Pqj\vdzx  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); R6`mmJ+'  
if(tmpFile.exists ()) 9':Hh'  
{ S|;}]6p  
bFirst = false; Q);}1'c  
read_nPos(); t|9vb  
} \II^&xSF  
else xSO5?eR"u  
{ ~[kI![  
nStartPos = new long[bean.getNSplitter()]; d|`8\fq  
nEndPos = new long[bean.getNSplitter()]; <Fv7JPN%  
} cp"{W-Q{$  
*3h_'3yo@  
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} i+Mg[x$.  
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public void run() e|>@ >F]K  
{ QxuU3#l  
//获得文件长度 \F\xZ.r  
//分割文件 Gm> =s  
//实例FileSplitterFetch R&:Qy7"  
//启动FileSplitterFetch线程 &|h9L'mr  
//等待子线程返回 z_#HJ}R=  
try{ X{[$4\di{  
if(bFirst) ug'^$geM  
{ 9 &Ry51  
nFileLength = getFileSize(); -<AGCiLz  
if(nFileLength == -1) dj4a)p|YN  
{ GO*D4<#u  
System.err.println("File Length is not known!"); In;P33'p  
} i5_l
//]  
else if(nFileLength == -2) O;&5> W,Z  
{ I.>8p]X  
System.err.println("File is not access!"); X)=m4\R  
} pcQkJF  
else EY.m,@{  
{ **oDQwW]*  
for(int i=0;i<nStartPos.length;i++) IL uQf-  
{ DGw*
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); }IdkXAB.  
} * bhb=~  
for(int i=0;i<nEndPos.length-1;i++) [
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{ c>! ^\  
nEndPos = nStartPos[i+1]; G)f!AuN=  
} !aJ6Uf%R  
nEndPos[nEndPos.length-1] = nFileLength; G8MLg#  
} Zlt,Us`  
} iSfRo31  
|oePB<N  
\@T;/Pj{[  
//启动子线程 sPl3JP&s  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; {qU;>;(  
for(int i=0;i<nStartPos.length;i++) h0A
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{ P)hGe3  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), d/@P;YN!  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 'c]Pm,Ls  
nStartPos,nEndPos,i); dDAl n+  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); DeeV;?:  
fileSplitterFetch.start(); epG =)gd=8  
} 16nU`TN  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), D'^%Q_;
u  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 5`lVC$cP  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", YY$Z-u(  
nEndPos = " + nFileLength); ,Ij/ ^EC}  
// fileSplitterFetch[nPos.length-1].start(); ??LE0i  
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OHnsfXO_V  
//等待子线程结束 \.GA"_y  
//int count = 0; 1=z\,~b  
//是否结束while循环 CL?=j| Ea  
boolean breakWhile = false; &Z9rQH81f>  
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e? |4O<@  
while(!bStop) !CY*
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{ W'Y(@  
write_nPos(); ~zvZK]JoX  
Utility.sleep(500); YUyYVi7clq  
breakWhile = true; A6E~GJa  
lS!O(NzqE'  
2^Z"4t4  
for(int i=0;i<nStartPos.length;i++) nU6UjC|3  
{ 9[ o$/x}  
if(!fileSplitterFetch.bDownOver) V@EyU/VJ  
{ 5yj6MaqJ  
breakWhile = false; .ezZ+@LI+#  
break; _fHj8- s/  
} &IsPqO  
} ~jz51[{v  
if(breakWhile) rZ.z!10  
break; o,?h}@  
*D`$oK,U  
6TXTJ]er  
//count++; 7&w[h4Lw  
//if(count>4) n;:C{5  
// siteStop(); =rkW325O  
} u_8Z^T  
^i8(/iwdJE  
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System.err.println("文件下载结束！"); PeLzZ'$D  
} (B?ZUXM,  
catch(Exception e){e.printStackTrace ();} m& D#5C  
} vTWm_ed+^  
8.7lc2aX  
5aXE^.
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//获得文件长度 ~\
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public long getFileSize() 6['o^>\}f  
{ S/l6c P  
int nFileLength = -1; #>sIXY  
try{ u%=2g'+)_  
URL url = new URL(siteInfoBean.getSSiteURL()); 8_O?#JYi  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); HXPq+  
httpConnection.setRequestProperty("User-Agent","NetFox"); R+=wSG]  
YTr+"\CkA  
$'::51  
int responseCode=httpConnection.getResponseCode(); 4AF.KX7  
if(responseCode>=400) `joyHKZI.  
{ Wdga(8t  
processErrorCode(responseCode); b dC  
return -2; //-2 represent access is error 8,e%=7h_e  
} dOKe}?}==  
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String sHeader; Lzcea+*uw  
~]n=TEJ>  
>Nx4 +|  
for(int i=1;;i++) "3_GFq  
{ c'5ls7?}O{  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 1S yG  
//Utility.log(in.readLine()); dx$+,R~y  
sHeader=httpConnection.getHeaderFieldKey(i); O]j<$GG!  
if(sHeader!=null) d b*J  
{ #3A|Z=,
5  
if(sHeader.equals("Content-Length")) *D1vla8  
{ 1(e64w@  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); .SNg
2.  
break; EW+QVu@  
} >t%@)]*N  
} [ A 7{}  
else ~)6EH`-  
break; _g'x=VJF  
} l 3 jlKB  
} ,3!4 D^  
catch(IOException e){e.printStackTrace ();} o,@(]e~  
catch(Exception e){e.printStackTrace ();} 1jaK N*  
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Utility.log(nFileLength); 4Tb"+Y
}  
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return nFileLength; ViG>gMGv  
} \p]B8hLW  
#wZH.i#  
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//保存下载信息（文件指针位置） _>8Q{N\- {  
private void write_nPos() $I4Wl:(~}  
{ U"~W3vwJ  
try{ KleiX7  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 5Yww,s  
output.writeInt(nStartPos.length); oY7jj=z#T  
for(int i=0;i<nStartPos.length;i++) tk>J mcTw  
{ M|{NC`fa  
// output.writeLong(nPos); 0s RcA-9  
output.writeLong(fileSplitterFetch.nStartPos); jdx T662q  
output.writeLong(fileSplitterFetch.nEndPos); ~=|QPO(d  
} J93xxj  
output.close(); 1xSG(!  
} $+$l?2  
catch(IOException e){e.printStackTrace ();} |IS$Om  
catch(Exception e){e.printStackTrace ();} F07X9s44E  
} p./0N.  
aK7}}  
!%.=35NS@E  
//读取保存的下载信息（文件指针位置） i6g=fx6j*  
private void read_nPos() v-/vj/4>  
{ $dA]GWW5A  
try{ ]b:>7_la  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 9Hd_sNUu\  
int nCount = input.readInt(); y*p02\)  
nStartPos = new long[nCount]; IIAmx[ b  
nEndPos = new long[nCount];  L|6I  
for(int i=0;i<nStartPos.length;i++)  T;V!>W37  
{ DgY !)cS  
nStartPos = input.readLong(); |"+Ufw^  
nEndPos = input.readLong(); `3@?)xa  
} l,zhBnD  
input.close(); h[Uo6`  
} <1 ;pyw y  
catch(IOException e){e.printStackTrace ();} e+MQmWA'F  
catch(Exception e){e.printStackTrace ();} yrd1J$  
} vTTXeS-b  
<XN=v!2;  
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9q  
private void processErrorCode(int nErrorCode) d`~~Ww1  
{ 5}c8v2R:B  
System.err.println("Error Code : " + nErrorCode); bvZ:5M  
}  G8!|Lo  
E%Ww)P  

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//停止文件下载 0=K8 nxdx  
public void siteStop() K9y~ e  
{ TPak,h(1  
bStop = true; ww #kc!'  
for(int i=0;i<nStartPos.length;i++) 6CSoQ|c{  
fileSplitterFetch.splitterStop(); 0%4OmLBT  
%%zlqd"0  
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} `csZ*$7  
} p@[ fZj  
//负责部分文件的抓取 <fV][W  
**FileSplitterFetch.java yc`*zLWh  
*/ q6<P\CSHy<  
package NetFox; P,F eF'J^  
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import java.io.*; KHgn  
import java.net.*; d ez4g  
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public class FileSplitterFetch extends Thread { ._Ww  
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s  
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String sURL; //File URL n?;rWq"  
long nStartPos; //File Snippet Start Position _A])q  
long nEndPos; //File Snippet End Position ic"8'Rwb  
int nThreadID; //Thread's ID tC5-^5[y  
boolean bDownOver = false; //Downing is over ~_c1h@  
boolean bStop = false; //Stop identical n.z,-H17  
FileAccessI fileAccessI = null; //File Access interface '+27_j  
${eV3LSC  
QWEE%}\3}  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Ak8Y?#"wz  
{  Ip:54  
this.sURL = sURL; wy0?*)~  
this.nStartPos = nStart; #V%98|"  
this.nEndPos = nEnd; v(!:HK0oeT  
nThreadID = id; YRFz]  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 w( _42)v]g  
} ZfK[o{9>  
!?/:p.  
P^48]Kj7  
public void run() 7 )rL<+  
{ _53~D=  
while(nStartPos < nEndPos && !bStop) ??U/Qi180  
{ \"Y,1in#  
p:z~>ca  
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try{ RAP-vVh/C  
URL url = new URL(sURL); CxZh^V8LP  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); l`i97P?/W  
httpConnection.setRequestProperty("User-Agent","NetFox"); \C h01LR"  
String sProperty = "bytes="+nStartPos+"-"; 2E[7RBFY+\  
httpConnection.setRequestProperty("RANGE",sProperty); I[d<SHo  
Utility.log(sProperty); ]JV'z<  
]bY]YNt{7]  
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InputStream input = httpConnection.getInputStream(); rp{|{>'`.q  
//logResponseHead(httpConnection); x3Y)l1gh  
b*M?\ aA  
nP]!{J]  
byte[] b = new byte[1024]; _lFw1pa#\  
int nRead; l $"hhI8  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) "\KBF  
{ IA({RE  
nStartPos += fileAccessI.write(b,0,nRead); mbGma  
//if(nThreadID == 1) kFV, Fg  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); . R/y`:1:W  
} j
)
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m<#12#D  
Utility.log("Thread " + nThreadID + " is over!"); 5<R m{  
bDownOver = true; [!-gb+L  
//nPos = fileAccessI.write (b,0,nRead); 6CIzT.  
} -p.\fvip  
catch(Exception e){e.printStackTrace ();} )AQ
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} 5UO+c(T  
} KP>9hEh  
^}B,0yUu'  
}$4z$&  
//打印回应的头信息 >[,eK=  
public void logResponseHead(HttpURLConnection con) ?'9IgT[*  
{ d%"XsbO  
for(int i=1;;i++) MA6 Vy  
{ ;ryNfP%  
String header=con.getHeaderFieldKey(i); !NkCki"W  
if(header!=null) 5$D"uAp<V  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); d#H9jg15e  
Utility.log(header+" : "+con.getHeaderField(header)); 5;UIz@BJ  
else -6HwGfU  
break; x
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} q`b6if"  
} Z,A$h>Z  
dQ.#8o=  
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public void splitterStop() N}K [Q
=  
{ ?YLq iAA  
bStop = true; D5D *$IC  
} @we1#Vz.  
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;*M@LP{*L  
} "J1A9|  
?<TJ}("/  
49$<:{~  
/* 7upko9d/  
**FileAccess.java MK=oGzK  
*//文件访问(定位，写) 0lg$zi x(  
package NetFox; H.@$#D  
import java.io.*; 2Jd(@DcJ2C  
% D  
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public class FileAccessI implements Serializable{ Qs6Vu)U=  
3k`Q]O=OU  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 LV^^Bd8Ct  
RandomAccessFile oSavedFile; v$|~ g'6  
long nPos; 3SP";3+  
:*M?RL@j  
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public FileAccessI() throws IOException ;7QXs39S  
{ Mh.1KI[t  
this("",0); :ZV|8xI  
} ERpAV-Zf  
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L7-BuW}&  
public FileAccessI(String sName,long nPos) throws IOException 1 :p'  
{ ew~Z/ A   
oSavedFile = new RandomAccessFile(sName,"rw"); >v.fH6P,}  
this.nPos = nPos; P1Hab2%+  
oSavedFile.seek(nPos); wtY)(ka  
} gEd A hfx  
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public synchronized int write(byte[] b,int nStart,int nLen) u ]e-IYH  
{ @M5+12FYt  
int n = -1; Lt't   
try{ N}?|ik
 
oSavedFile.write(b,nStart,nLen);  GfE>?mG  
n = nLen; d:(Ex^^  
} L,[Q/$S8  
catch(IOException e) ny5P*yWEh  
{ QnWE;zN[7A  
e.printStackTrace (); 5H0qMt P  
}
@:C)^f"  
:>0ywg  
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return n; yV(#z2|  
} 79v+ze  
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} u7L?9  
.\R9tt}  
tYu<(Z(l)  
/* 'x*C#mt  
**SiteInfoBean.java bY" zK',m  
*/ $oBs%.Jp  
package NetFox; >K
u4Il+36  
!9;m~T7.  
~)U50.CH  
public class SiteInfoBean { ,8@<sFB'  
D&%8JL  
o08WC'bX  
private String sSiteURL; //Site's URL |g&V? lI  
private String sFilePath; //Saved File's Path Lv%3 jj  
private String sFileName; //Saved File's Name atTR6%!6  
private int nSplitter; //Count of Splited Downloading File 41
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.q9Sg8G  
3ZXAAV  
public SiteInfoBean() LZV-E=`  
{//nSplitter的缺省值为5 r1L@p[>  
//default value of nSplitter is 5 \sNgs#{7E7  
this("","","",5); ieZ$@3#&z  
} /mkT7,]  
a{kJ`fK   
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ,1sbY!&ekL  
{ yYP_TuNa  
sSiteURL= sURL; e )0 ]WJ  
sFilePath = sPath; & FhJ%JK  
sFileName = sName; t1w5U+z  
this.nSplitter = nSpiltter; zZCl]cql  
>+M[!;m}  
8^UF0>`'  
} jY=y<R_oK  
@_ %RQO_X  
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public String getSSiteURL() rN}pi@  
{ & kC  
return sSiteURL; /~NX<Ye&  
} A6z,6v6  
 d$$5&a  
q} e#L6cM  
public void setSSiteURL(String value) >(RkoExO/  
{ _ $F=A  
sSiteURL = value; w+)${|N?  
} "\o#YC  
w6vbYPCN  
KuJ)alD;1  
public String getSFilePath() *tqD:hiF  
{ [7I:Dm  
return sFilePath; dA)T>  
} jFN0xGZ  
#]}Ii{1?Y  
##jJaSxG  
public void setSFilePath(String value) k{qxsNM  
{ ,Cr%2Wg-  
sFilePath = value; &>jz[3  
} Q
!l(2nva  
Y$JVxly  
8_%GH}{  
public String getSFileName()
AG,><UP  
{ F$t]JM  
return sFileName; q;eb  
} #/YS  
kLgkUck8]  
*u+DAg'&  
public void setSFileName(String value) ~5P9^`KNH  
{ hz:7W8  
sFileName = value; p<L7qwOii  
} yj:@Fg-3g  
BM!ZdoKrKt  
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public int getNSplitter() u> {aF{  
{ 'yiv.<4  
return nSplitter; D6VdgU|  
} SJiQg-+<Uf  
rj=as>6B  
1 uU$V =  
public void setNSplitter(int nCount) ?Bu*%+  
{ +R*DE5dz  
nSplitter = nCount; dj0%?g>  
} 9`f@"%h  
} sQgz}0_=)  

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kK75(x  
/* }d.X2?  
**Utility.java YoKE=ln7  
*/ i9ySD  
package NetFox; =;Q/bD->  
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$@
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public class Utility { cSPQ NYU:  
FJ0I&FyWs  
Jr5S8c|"  
public Utility() 9QU\J0c/  
{ : #a  
4Fp[94b  
UBL{3s^"  
} 0Md>-H;ZY  
_$UJ'W})/  
//线程睡眠 *}]#E$  
public static void sleep(int nSecond) ;.4y@?B  
{ 6Q:Wo)^!  
try{ q(n"r0)=  
Thread.sleep(nSecond); sK#)k\w>  
} iZNS? ^U  
catch(Exception e) D9+qT<ojN  
{ ZLzc\>QX  
e.printStackTrace (); [63\2{_^v  
} 4. R(`#f  
} ,&BNN]k  
+2iD9X{$MX  
//日志 1{N+B#*<[X  
public static void log(String sMsg) ^iONC&r  
{ 0`E G-Hw  
System.err.println(sMsg); 6Amt75RY  
} k^cZePqE6d  
L-(bw3Yr>  
gY7sf1\wX  
public static void log(int sMsg) i bzY&f  
{ /phMrL=  
System.err.println(sMsg); !;>s.]  
} O+W<l
:|$  
} cvsH-uAp  
-*7i:mg  
VJ\qp%  
/* +c%jOl  
**TestMethod.java T+L=GnYl  
*/ OJu>#   
package NetFox; 4w+AOWjd  
aV$kxzEc  
mo^E8t.  
public class TestMethod { 1'/ [x(/]d  
93*d:W8Vr  
G_1r&[N3  
public TestMethod() {^1
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{ ///xx/weblogic60b2_win.exe U,!qNi}  
try{ ]EHs
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SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ?7fqWlB  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); \:+\H0Bz  
SiteFileFetch fileFetch = new SiteFileFetch(bean); :!_l@=l  
fileFetch.start(); R3G\Gchd  
} f"Iui  
catch(Exception e){e.printStackTrace ();} 2|j=^  
t]SB.ja  
-+[Lc_oNPx  
} YCE *Dm  
L~f~XgQ  
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public static void main(String[] args) R`]@.i4tt  
{ lv?`+tU2_  
new TestMethod(); cWo>DuW&  
} Rd HCbk  
} IuP~Vt{m  
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