http断点续传简单实现（java)

/* Wv||9[Rd  
**SiteFileFetch.java Eh*(N(`  
*/ SuXeUiK.[  
package NetFox; "hk {"0E  
import java.io.*; G#fF("Ndu`  
import java.net.*; b
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public class SiteFileFetch extends Thread { O(6j:XD  
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7,zE?KG /  
SiteInfoBean siteInfoBean = null; //文件信息Bean ~=Q^]y,  
long[] nStartPos; //开始位置 [ ebk u_  
long[] nEndPos; //结束位置 !;;7:!)P  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 &M:o(
T  
long nFileLength; //文件长度 ]!j%Ad  
boolean bFirst = true; //是否第一次取文件 ,m8mh)K?0>  
boolean bStop = false; //停止标志 L5'?.9]  
File tmpFile; //文件下载的临时信息 j^%N:BQ&  
DataOutputStream output; //输出到文件的输出流 g^^pPVK_  
 md,KRE  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） `FEa(Q+s  
public SiteFileFetch(SiteInfoBean bean) throws IOException _M+7)[xj=  
{ Nv^byWqu  
siteInfoBean = bean; )KEW`BC5T  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); o{hX?,4i  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); rzs-c ?  
if(tmpFile.exists ()) =t`cHs29  
{ 2$ &B@\WY  
bFirst = false; QYi4A"$`  
read_nPos(); {xH?b0>  
} I _gE`N  
else Y2;2Exp^  
{ <uxLG;R  
nStartPos = new long[bean.getNSplitter()]; }8POm#  
nEndPos = new long[bean.getNSplitter()]; <#RVA{  
} Rw|'LaW  
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} |-)8=QDz)r  
[F'|KcE3  
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public void run() Zazff@O *  
{ 7YR|6{@  
//获得文件长度 zh|9\lf  
//分割文件 |q58XwU `  
//实例FileSplitterFetch &w#!
 
//启动FileSplitterFetch线程 bMGn&6QiP[  
//等待子线程返回 fCwE1r*^  
try{ ?3p7MjvZ  
if(bFirst) tAF?.\x"g  
{ Z&Ciy n  
nFileLength = getFileSize(); |K"Q>V2y  
if(nFileLength == -1) :nQlS  
{
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System.err.println("File Length is not known!"); y TD4![  
} An$2='=/  
else if(nFileLength == -2) >WIc"y.  
{ 'gvR?[!t  
System.err.println("File is not access!"); Zym6btc  
} REU,"  
else sVK?sBs]  
{ IQRuqp KL  
for(int i=0;i<nStartPos.length;i++) oojl"j4  
{ Q-n8~Ey1a  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); TK fN`6  
} @kqxN\DE  
for(int i=0;i<nEndPos.length-1;i++) =c'4rJ$+  
{ I70c,4_G  
nEndPos = nStartPos[i+1]; N+=
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} yQE'!m  
nEndPos[nEndPos.length-1] = nFileLength; ,^1

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} `oJQA$UD  
} yGdX>h  
+cfEyiub  
qcS.=Cj?)  
//启动子线程 
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ZpV]X(Px(o  
for(int i=0;i<nStartPos.length;i++) 5e/YEDP  
{ C/!.VMl^  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), YV<y-,Io  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), OT%E|) 6'  
nStartPos,nEndPos,i); ^$K&Met  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); #;]#NqFX  
fileSplitterFetch.start(); %.Ma_4o Z  
} #i[:oC6m:  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), m&:&z7^p  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); FH+X<  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ",  :\\NK/"  
nEndPos = " + nFileLength); BDB*>y7(  
// fileSplitterFetch[nPos.length-1].start(); YYv0cV{E  
H<(F$7Q!\  
cb|+6m~  
//等待子线程结束 RdYmh>c  
//int count = 0; &-3e3)  
//是否结束while循环 eV[{c %wN:  
boolean breakWhile = false; xB *b7-a  
f#0HiE!  
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while(!bStop) 3iCe5VF  
{ ~_
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write_nPos(); ye^x>a['  
Utility.sleep(500); *;fTiL  
breakWhile = true; (?jK|_  
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Qr.{_M  
for(int i=0;i<nStartPos.length;i++) V<QpC5  
{ Lce,]z\_  
if(!fileSplitterFetch.bDownOver) |+Y-i4t  
{ D+]mKPB  
breakWhile = false; p&(0e,`z/  
break; uY]';OtG  
} 4uXGpsL  
} Kxsd@^E  
if(breakWhile) ?"yjgt7+y  
break; ^E70$yB^  
Y&6jFT_  
!db=Iz5)  
//count++; S7+>Mk  
//if(count>4) ht-'O"d:  
// siteStop(); O*u   
} /TMVPnvz.  
| .jWz
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System.err.println("文件下载结束！"); T<uX[BO-a  
} ,RPb<3 B  
catch(Exception e){e.printStackTrace ();} $_<[kci%  
} Ku[q#_7  
4e#g{,  
*
).  
//获得文件长度 ,a5q62)q  
public long getFileSize() MHpGG00,  
{ WI1YP0V  
int nFileLength = -1;  !XTzsN  
try{ gW~YB2 $  
URL url = new URL(siteInfoBean.getSSiteURL()); {MtJP:8Jp  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); \;XJ$~>  
httpConnection.setRequestProperty("User-Agent","NetFox"); g3
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int responseCode=httpConnection.getResponseCode(); gbdzS6XW~  
if(responseCode>=400) \4 b^*`d  
{ \(??Ytc<B  
processErrorCode(responseCode); <SE-:T]sBz  
return -2; //-2 represent access is error e/4C` J-  
} H ezbCwsx&  
.nY}_&  
rw)!>j+&A  
String sHeader; Da<`| l  
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92j[b_P  
for(int i=1;;i++) 1!zd#TX  
{ @Ov}X]ELi  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ^4IJL",  
//Utility.log(in.readLine()); RSAGSGp  
sHeader=httpConnection.getHeaderFieldKey(i); 3_RdzW}f  
if(sHeader!=null) ?jmL4V2-f  
{ <mJ8~  
if(sHeader.equals("Content-Length")) /sYr?b!/<6  
{ V
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nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); U^}7DJ  
break; )W_akUL  
} B
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} 6# bTlmcg  
else # ,H!<X;SS  
break; oHfr glGX  
} 0[H/>%3O  
} W2`3PEa  
catch(IOException e){e.printStackTrace ();} $J4)z&%dr  
catch(Exception e){e.printStackTrace ();} BJ_"FG  
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Utility.log(nFileLength); <0Y<9+g!  
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return nFileLength; KO`dAB F}  
} Pc?"H!Hkn  
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//保存下载信息（文件指针位置） -~RGjx  
private void write_nPos() Ugo!  
{ e1b?TF@lz  
try{ u)zv`m  
output = new DataOutputStream(new FileOutputStream(tmpFile)); *N: $,x
f  
output.writeInt(nStartPos.length); Z0M,YSnz  
for(int i=0;i<nStartPos.length;i++) 6pb~+=3n  
{ cBbumf9C  
// output.writeLong(nPos); n2_;:=  
output.writeLong(fileSplitterFetch.nStartPos); \-Xtbm  
output.writeLong(fileSplitterFetch.nEndPos); *qYw  
} O46v  
output.close(); 2rC&  
} b)
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catch(IOException e){e.printStackTrace ();} +BO kHXk1  
catch(Exception e){e.printStackTrace ();} a>-qHX-l  
} }
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//读取保存的下载信息（文件指针位置） vgDpo@fz8  
private void read_nPos() G{,DoCM5WL  
{ )/[L)-~y~  
try{ h 2JmRO  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ,B_tA
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int nCount = input.readInt(); h-O;5.m-P  
nStartPos = new long[nCount]; Q`.q,T8I  
nEndPos = new long[nCount]; T~L V\}h  
for(int i=0;i<nStartPos.length;i++)  y<m[9FC}  
{ =j~:u.hc'  
nStartPos = input.readLong(); z
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nEndPos = input.readLong(); &tf(vU;,'  
} JC9$"0d7  
input.close(); RL\?i~'KH  
} KXl!VD,#`=  
catch(IOException e){e.printStackTrace ();} 79}jK"Gc  
catch(Exception e){e.printStackTrace ();} Bxw(pACf  
} oP4+:r)LKD  
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private void processErrorCode(int nErrorCode) UU[z\^w| E  
{ f}*:wj  
System.err.println("Error Code : " + nErrorCode); SsZSR.tD  
} b$Dh|-8  
vGPsjxk&  
nN-S5?X#  
//停止文件下载 \G)F*  
public void siteStop() %QGw`E   
{ H[OgnnM  
bStop = true; #pK" ^O*!  
for(int i=0;i<nStartPos.length;i++) bi",DKU{l  
fileSplitterFetch.splitterStop(); v@M^ukk'}  
wsH_pF  
^Mc9MZ)  
} Z_S{$D  
} ,p(&G_  
//负责部分文件的抓取 7OG:G z+)x  
**FileSplitterFetch.java 1 JIU5u)  
*/ IPYwUix  
package NetFox; dkCUU  
Sl^PELU  
:lvBcFw  
import java.io.*; z,^~H  
import java.net.*; V?wV*]c  
$7g+/3Fu^  
#)]t4wa_W  
public class FileSplitterFetch extends Thread { 3/Z>W|w#w  
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String sURL; //File URL yzzJKucVU:  
long nStartPos; //File Snippet Start Position sO6=w%l^  
long nEndPos; //File Snippet End Position c>^(=52Q  
int nThreadID; //Thread's ID :|niFK4  
boolean bDownOver = false; //Downing is over 3z2 OW@zL$  
boolean bStop = false; //Stop identical 650qG$  
FileAccessI fileAccessI = null; //File Access interface /"u37f?[^  
V(DY!f_%  
kV5)3%?  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Fr  
{ y*-_  
this.sURL = sURL; y;8&J{dd  
this.nStartPos = nStart; .#|?-5q/iN  
this.nEndPos = nEnd; hdrsa}{g  
nThreadID = id; vI5lp5( -3  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ,bdjk(  
} ?&~q^t?u  
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public void run() [p`5$\e  
{ ` K{k0_{  
while(nStartPos < nEndPos && !bStop) >5L_t   
{ zN
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.\^0RyJE  
try{ Em@:QmEN  
URL url = new URL(sURL); ^sLx3a  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); .)!QsBU  
httpConnection.setRequestProperty("User-Agent","NetFox"); HRDpFMA/~  
String sProperty = "bytes="+nStartPos+"-"; NBc^(F"  
httpConnection.setRequestProperty("RANGE",sProperty); yivu|q  
Utility.log(sProperty); |9c~kTjK  
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InputStream input = httpConnection.getInputStream(); M }d:B)cz  
//logResponseHead(httpConnection); `<X-3)>;G  
$Xu3s~:S  
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byte[] b = new byte[1024]; 'YNdrvz  
int nRead; cZ?QI6|[  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) fj5g\m  
{ $El-pMq  
nStartPos += fileAccessI.write(b,0,nRead); /;Tc]  
//if(nThreadID == 1) g8%O^)d=>  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); nG!<wlY14P  
} -Qn7+?P  
"+"=iwEAz  
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Utility.log("Thread " + nThreadID + " is over!"); d7X&3L%Oq  
bDownOver = true; :;7I_tb  
//nPos = fileAccessI.write (b,0,nRead); M`Er&nQs  
} s3Vb2C*  
catch(Exception e){e.printStackTrace ();} Z nc(Q  
} @dDeOnF  
} 2ndn8_l  
kW g.-$pp  
WD[eoi  
//打印回应的头信息 m.e]tTe  
public void logResponseHead(HttpURLConnection con) }9'`3vsJ  
{ jV3PTU  
for(int i=1;;i++) 8vY-bm,e  
{ 'jtC#:ePK  
String header=con.getHeaderFieldKey(i); >M,oyM"s  
if(header!=null) R2~Tr$:  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); i<m(neX[H  
Utility.log(header+" : "+con.getHeaderField(header)); I0)`tQ+  
else u*l|MIi6J  
break; Z'JS@dV  
} 9oWU]A\k>  
} 0mY Y:?v  
NI >%v  
iQwQ5m!d &  
public void splitterStop() |"3<\$[  
{ G'ykcB._  
bStop = true; /U~|B
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} ETe4I`d{  
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} }SN( ^3N  
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/* `2s!%
/  
**FileAccess.java WNjwv/  
*//文件访问(定位，写) H",B[ YK  
package NetFox; a|aVc'j  
import java.io.*; /Rp]"S vt  
aV3:{oL  
NR{wq|"  
public class FileAccessI implements Serializable{ aER|5!7(2\  
(C2 XFg_  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 BT$p~XB  
RandomAccessFile oSavedFile;  `zwz  
long nPos; :$5A3i  
sGvbL-S-f:  
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public FileAccessI() throws IOException CT|+?  
{ 092t6D}  
this("",0); yC,/R371k  
} XC4Z,,ah"  
&J[a.:..  
Pf?kNJ*Tv)  
public FileAccessI(String sName,long nPos) throws IOException bQAznd0  
{ |m19fg3u  
oSavedFile = new RandomAccessFile(sName,"rw"); TBhM^\z  
this.nPos = nPos; .p`4>XA  
oSavedFile.seek(nPos); adON&<  
} o9?@jjqH  
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~,'{\jDrS  
public synchronized int write(byte[] b,int nStart,int nLen) j)1yv.  
{ 6Z/`p~e  
int n = -1; >%JPgr/ 8  
try{ jXcJ/g(X3  
oSavedFile.write(b,nStart,nLen); E$d3+``  
n = nLen; WKf<% E$  
} )fH Q7  
catch(IOException e) qZoDeN-CC  
{ 0QQss  
e.printStackTrace (); ,CO2d)}  
} $o6/dEKQ  
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return n; |J`EM7qMK  
} ^-;S&=  
O--p)\  
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} _iwG'a[`  
wAMg"ImJ  
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/* 6*8Wtq  
**SiteInfoBean.java <Ij!x`MS+  
*/ S"Al[{  
package NetFox; 5Iu5N0cn  
E}^V@ :j>  
rK~-Wz
wu  
public class SiteInfoBean { |5@Ra@0  
_ %s#Cb  
;w{<1NH2+.  
private String sSiteURL; //Site's URL IQQv+af5  
private String sFilePath; //Saved File's Path hW7u#PY  
private String sFileName; //Saved File's Name :]"5UY?oF  
private int nSplitter; //Count of Splited Downloading File `At.$3B  
lR(9;3  
u ExLj6  
public SiteInfoBean() ?2<QoS  
{//nSplitter的缺省值为5 mq:k|w^6  
//default value of nSplitter is 5 #-az]s|N  
this("","","",5); p^l#Wq5  
} u#05`i:Z  
(qcFGM22U  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) w,~*ead  
{ iAd&o`C  
sSiteURL= sURL; +cpb!YEAb
 
sFilePath = sPath; T2{e1 =Z7  
sFileName = sName; +]
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this.nSplitter = nSpiltter; wl=tN{R  

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31n"w;  
} AvL /gt:  
;R$G.5h  
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public String getSSiteURL() =D zrM%  
{ L K&c~ Uy  
return sSiteURL; ,@Csa#  
} pEB3qGA  
\F _1C=  
L F?/60  
public void setSSiteURL(String value) lL}6IZ5sb  
{ D5zc{) /  
sSiteURL = value; Vjs2Yenx  
} )L<.;`g4x  
[*%lm9 x  
H4Bt.5O*  
public String getSFilePath() Owp]>e  
{ E2hsSqsu=  
return sFilePath; "jZZ>\  
} 4vg,g(qi<  
QW..=}pL  
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public void setSFilePath(String value) g}9,U&$]y  
{ |:)Bo<8  
sFilePath = value; Y XhZWo{B  
} 'm0WPS/6E  
Q}#4Qz~n  
M]8>5Zx.  
public String getSFileName()  ;LS.  
{ c<13r=+  
return sFileName; cGE{dWz  
} 1@Ba7>%'  
<n_?$ TJ  
6>?qBWW  
public void setSFileName(String value) \^1^|a"  
{ ~HY)$Yp;  
sFileName = value; MpKXC  
} ~#gc{C@  

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FC 8<D  
public int getNSplitter() W *0!Z:?  
{ Q_T,=y  
return nSplitter; {UH45#Ua  
}
2tU3p<[  
_9oKW;7f7  
(R=ZI  
public void setNSplitter(int nCount) dC<%D'L*  
{ >MJ%6A>  
nSplitter = nCount; D[W` q#W  
} w !kk(QMV  
} /A5=L<T6F  
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/* `LH9@Z{  
**Utility.java '3XOU.  
*/ DN9x<
%/-  
package NetFox; WLWfe-  
\;%D;3Au  
*7*_QW%?A  
public class Utility { [1~3\-Y  
F_u?.6e]  
z:UkMn[  
public Utility() ym p*:
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{ kFJ]F |^7  
bO6z;
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} Jv(E'"H  
zt((TD2  
//线程睡眠 :z?T/9,C  
public static void sleep(int nSecond) G>Bgw>#_  
{ W9Us I  
try{ qPN  
Thread.sleep(nSecond); ?,v@H$)3_  
} ,:.8s>+i  
catch(Exception e) -Hi_g@i*XW  
{ +Kmxo4p  
e.printStackTrace (); AED 9vDE  
} j%vxCs>  
} U;4;
>  
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//日志 PVKq&Q?  
public static void log(String sMsg) p<VW;1bt5  
{ yYC\a7Al4  
System.err.println(sMsg); r|jBKq~  
} LGy!{c  
*/]1?M@P)  
Xp^>SSt:4  
public static void log(int sMsg) IxP$lx  
{ g2lv4Tiq-  
System.err.println(sMsg); *!EHs04  
} a 8jG')zg  
} :Ea]baM"  
t5p#g<$  
.|ZnU]~T  
/* [s!cc:JR
 
**TestMethod.java is-{U?-  
*/ x(zW<J5X"  
package NetFox; z:$TW{%M  
TwE&5F*  
%ye4FwkRy  
public class TestMethod { l5k]voG  
HQ|{!P\/?U  
y/?;s]>b  
public TestMethod() 9;c]_zt  
{ ///xx/weblogic60b2_win.exe VM ny>g&3  
try{ B
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SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); *r3u=oWb  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); hmd,g>J:<  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 1<9m^9_ro  
fileFetch.start(); #^/&fdK~A  
} (aH_K07  
catch(Exception e){e.printStackTrace ();} }%-`CJ,  
yYTiAvN  
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} D#9W [6  
?+#E&F  
]+S.#x`#
 
public static void main(String[] args) ]pA}h.R#-  
{ SY2B\TV  
new TestMethod(); mE]W#?   
} dTP$7nfe
 
} T%F8=kb-9  
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