http断点续传简单实现（java)

/* W}6OMAbsE;  
**SiteFileFetch.java ya`Z eQ-p  
*/ 9(-f)$u  
package NetFox; ~<Eu @8+_  
import java.io.*; -l(G"]tRB  
import java.net.*; i#4}xvi  
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public class SiteFileFetch extends Thread { o5h*sQ9  
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SiteInfoBean siteInfoBean = null; //文件信息Bean a_
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long[] nStartPos; //开始位置 V*d@@%u**  
long[] nEndPos; //结束位置 n
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FileSplitterFetch[] fileSplitterFetch; //子线程对象 y=HM]EH>  
long nFileLength; //文件长度 %]"eN{Uvn  
boolean bFirst = true; //是否第一次取文件 n{*A<-vL  
boolean bStop = false; //停止标志 {JGXdp:SB  
File tmpFile; //文件下载的临时信息 jjJvyZi~J  
DataOutputStream output; //输出到文件的输出流 UlNx5l+k  
}.L:(z^L,Y  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） m#Y[EPF=|  
public SiteFileFetch(SiteInfoBean bean) throws IOException %4$J.6M
 
{ L9Z\|L5  
siteInfoBean = bean; bJ!(co6t  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); &s0_^5B0  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); H`T8ydNXa  
if(tmpFile.exists ()) qh~$AJ9sB  
{ +o3 ZQ9  
bFirst = false; ->9waXRDz)  
read_nPos(); +T8h jOkC  
} z*ly`-!  
else D~Rv"Hh  
{ Y@l>4q")  
nStartPos = new long[bean.getNSplitter()]; '/U%-/@  
nEndPos = new long[bean.getNSplitter()]; VX6M4<8  
} 'hNRIM1  
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} K3;~|U-l  
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public void run() ET\>cxSp  
{ M`D`-vv  
//获得文件长度 4p6\8eytq.  
//分割文件 8+mu'RZ X  
//实例FileSplitterFetch W.sH  
//启动FileSplitterFetch线程 /Z1>3=G by  
//等待子线程返回
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try{ {>h,@  
if(bFirst) Dzr(Fb  
{ iezY+`x4  
nFileLength = getFileSize(); MA+{7 [  
if(nFileLength == -1) nd)`G$gL  
{ j
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System.err.println("File Length is not known!"); .22}=z  
} 'GF<_3I2l  
else if(nFileLength == -2) BK 9+fO  
{ ]N^>>k  
System.err.println("File is not access!"); 0f;`Zj0l8  
} 1 ~s$<  
else =`+c}i?  
{ [A
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for(int i=0;i<nStartPos.length;i++) ijeas<  
{ $wm8N.I3I  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); K<vb4!9Z9  
} G\C>fwrP_  
for(int i=0;i<nEndPos.length-1;i++) 0?w
4  
{ @$7l  
nEndPos = nStartPos[i+1]; O_P8OA#|  
} fX/k;0l  
nEndPos[nEndPos.length-1] = nFileLength; QI4a@WB]ok  
} 91oAg[@4G  
} ,R*YI  
&`B Tw1u  
mQ=nU  
//启动子线程 3e?a$~9  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; \Lz4ZZjSY  
for(int i=0;i<nStartPos.length;i++) `ZPV.u/  
{ a=r^?q'/  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), eMOnzW|h  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), }&Ul(HR  
nStartPos,nEndPos,i); JPM W|JT  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Clmz}F  
fileSplitterFetch.start(); ?{(Jy
*  
} 5 8n(fdE  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), nC@UK{tVa  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); xG8z4Yu   
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", w1,6%?p(O  
nEndPos = " + nFileLength); 8;fi1 "F;}  
// fileSplitterFetch[nPos.length-1].start(); 1z-Q~m@@  
+"3K)9H  
%Hpz^<`  
//等待子线程结束 W~?mr!`  
//int count = 0; K{__rO  
//是否结束while循环 4>Y\Y$3  
boolean breakWhile = false; Rf#t|
MW*#  
;|D8"D6]  
;T|hNsSt  
while(!bStop) s}Q*zy  
{ 2X`5YN;  
write_nPos(); nD!5I@D  
Utility.sleep(500); te b/  
breakWhile = true; %)}y[ (  
pVC;''E  
OcZ8:`=%  
for(int i=0;i<nStartPos.length;i++) ;hkzL_' E)  
{ !3Ed0h]Bfa  
if(!fileSplitterFetch.bDownOver) 8gXf4A(N  
{ ~Aoo\fN_U  
breakWhile = false; e)kVS}e?  
break; vFH1hm  
} P3+?gW'  
} (T8dh|  
if(breakWhile) dL|*#e  
break; f1RX`rXf  
JAS!eF  
(E<QA  
//count++; /u pDbP.O  
//if(count>4) h%!N!\  
// siteStop(); `cpUl*Y=  
} 11BfJvs:  
oWcBQ|   
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System.err.println("文件下载结束！"); > m##JzWLr  
} k-|b{QZ8!;  
catch(Exception e){e.printStackTrace ();} O_|p{65
  
} PJ'.s  
8BggK6X  
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//获得文件长度 )jm u*D5N  
public long getFileSize() 9p%8VDF=  
{ Pskg68W  
int nFileLength = -1; +^V%D!.$@  
try{ nI<Ab_EB  
URL url = new URL(siteInfoBean.getSSiteURL()); |emZZj  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ]?n~?dD{]  
httpConnection.setRequestProperty("User-Agent","NetFox"); j[&C6l+wH  
=7 ${bp!  
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int responseCode=httpConnection.getResponseCode(); z]0UW\S/  
if(responseCode>=400) F'3-*>]P  
{ D",~?  
processErrorCode(responseCode); &46Ro|XE`  
return -2; //-2 represent access is error ?%wM8
?  
} p<AzpkU,A  
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@Yzc?+x  
String sHeader; ="AJ&BqHd  
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for(int i=1;;i++) V8IEfU  
{ $S{]` +  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); jLgx(bM
n  
//Utility.log(in.readLine()); e2*Fe9:  
sHeader=httpConnection.getHeaderFieldKey(i); X0Zr?$q  
if(sHeader!=null) WJ m:?,  
{ hwB>@r2  
if(sHeader.equals("Content-Length")) M$+2f.(>k)  
{ Wz-7oP%;I  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 'qnnZE  
break; -40OS=wpA  
} 8[mj*^P  
} z!/ MBM  
else h;Se.{  
break; @Sd l~'"  
} 5Q.z#]Lg  
} ,`;D
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catch(IOException e){e.printStackTrace ();} HzD=F
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catch(Exception e){e.printStackTrace ();} BZ-)XF'4  
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Utility.log(nFileLength); )1 =|\  
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return nFileLength; e+7x &-+  
} {Wh7>*p{3  
kKil]L  
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//保存下载信息（文件指针位置） r4(Cb_  
private void write_nPos() ju%t'u\'  
{ g xf|L>=  
try{ !>gu#Q{\-  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Oa#m}b  
output.writeInt(nStartPos.length); Mg}8 3kS  
for(int i=0;i<nStartPos.length;i++) Nw|m"VLb  
{ 4>$weu^  
// output.writeLong(nPos); {5N!udLDr5  
output.writeLong(fileSplitterFetch.nStartPos); SM@RELA'Lb  
output.writeLong(fileSplitterFetch.nEndPos); #E#.`/4  
} GPVqt"TY  
output.close(); ye-R
  
} _Vf0MU;3f+  
catch(IOException e){e.printStackTrace ();} _/%,Z
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catch(Exception e){e.printStackTrace ();} SwVdo|%.?  
} .*+KQA8  
)3RbD#?  
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//读取保存的下载信息（文件指针位置） +7|Qd}\X  
private void read_nPos()  t_Rpeav  
{ /pOK4"  
try{ d:1TSJff%/  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Nw=mSW^E  
int nCount = input.readInt(); 2Ed  
nStartPos = new long[nCount]; X__>r ?oJ  
nEndPos = new long[nCount]; +ZxG<1&  
for(int i=0;i<nStartPos.length;i++) x0dO^D  
{ Nq=r404  
nStartPos = input.readLong(); ~[d|:]  
nEndPos = input.readLong(); Z$&i"1{  
} dJYQdo^X  
input.close(); Bm&%N?9  
} Lp}>WCams  
catch(IOException e){e.printStackTrace ();} &*r'Sx)V  
catch(Exception e){e.printStackTrace ();} b&~s}IX
 
} u"*Wo'3I|  
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private void processErrorCode(int nErrorCode) A/+bwCDP  
{ _]~= Kjp  
System.err.println("Error Code : " + nErrorCode); 98^o9i  
} (hv>vfY@  
5gnmRd  
;zc
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//停止文件下载 ON~K(O2g(  
public void siteStop() l{b*YUsz>  
{ BvA09lK  
bStop = true; XK7$Xbd  
for(int i=0;i<nStartPos.length;i++) j/+e5.EX/  
fileSplitterFetch.splitterStop(); jaq`A'o5  
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;`P}\Q{  
} b08s610fk  
} x!@P|c1nKC  
//负责部分文件的抓取 Y']D_\y  
**FileSplitterFetch.java v1Wz#oP  
*/ /5Zt4&r  
package NetFox; E0Neo _7  
!Hp H  
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import java.io.*; Q lg~S1D_v  
import java.net.*; 39+6ZTqx
 
ca{u"n  
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public class FileSplitterFetch extends Thread { ~-.^eT kP  
+~~&FO2  
m2o)/:
 
String sURL; //File URL |`50Tf\J  
long nStartPos; //File Snippet Start Position 6YCFSvA#/  
long nEndPos; //File Snippet End Position k-uwK-B}v+  
int nThreadID; //Thread's ID }&h*bim  
boolean bDownOver = false; //Downing is over o :tz_5  
boolean bStop = false; //Stop identical M((]> *g  
FileAccessI fileAccessI = null; //File Access interface }#h>*+Q  
h*JzJ0X  
/>,Tq!i\4}  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException O5:2B\B  
{ =Hs[peO*  
this.sURL = sURL; }j. [h;C6  
this.nStartPos = nStart; 6HyndB^  
this.nEndPos = nEnd; !y{t}|U/d  
nThreadID = id; wC~ra:/?:7  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 4tb y N  
} _poe{@h!  
^XIVWf#`H  
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public void run() dmkd.aP4  
{ Zoi\r  
while(nStartPos < nEndPos && !bStop) l1h;ng6  
{ s^n}m#T  
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try{ :172I1|7  
URL url = new URL(sURL); 2W_p)8t>b  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); DG!H8^  
httpConnection.setRequestProperty("User-Agent","NetFox"); [z^db0PU  
String sProperty = "bytes="+nStartPos+"-"; \~:Uj~  
httpConnection.setRequestProperty("RANGE",sProperty); AUk,sCxd  
Utility.log(sProperty); 3i c6!T#t"  
=QiVcw,G#  
)t-Jc+*A>  
InputStream input = httpConnection.getInputStream(); +?!x;qS^  
//logResponseHead(httpConnection); m<DiYxK  
y ;$8C  
'K9{xI@N  
byte[] b = new byte[1024]; 69o,T
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int nRead; PU6Sa-fQ2,  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) APC,p,"  
{ BV8-\R@  
nStartPos += fileAccessI.write(b,0,nRead); 5:o$]LkOWC  
//if(nThreadID == 1) d? Old  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ,>^6ztM  
} <r{M(yZ?@  
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(np %urx!  
Utility.log("Thread " + nThreadID + " is over!"); EAgNu?L  
bDownOver = true; SREe, e\  
//nPos = fileAccessI.write (b,0,nRead); @4'bI)  
} yz CQ  
catch(Exception e){e.printStackTrace ();} jBTXs5q  
} J9kmIMq-C  
} FHu -';  
c~1X/,biA  
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//打印回应的头信息 c:R`]4o  
public void logResponseHead(HttpURLConnection con) Dj~]]  
{ Y~</vz+H  
for(int i=1;;i++) y$]gmg  
{ 4a&*?=GG  
String header=con.getHeaderFieldKey(i); "0nT:!BZ  
if(header!=null) bvu
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//responseHeaders.put(header,httpConnection.getHeaderField(header)); @Y~R*^n"}  
Utility.log(header+" : "+con.getHeaderField(header)); yJ
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else  fn1G^a=  
break; `o.DuvQ E  
} ~is$Onf99#  
} q:y_#r"_y  
/lC&'hT  
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public void splitterStop() }[[  
{ vu&%e\gM  
bStop = true; Zj*kHjn"
 
} L+c7.l.yT  
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} 2 f"=f^rf  
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9'qU4I  
/* YSvZ7G(m>  
**FileAccess.java '%u7XuU-]  
*//文件访问(定位，写) .)7r /1o  
package NetFox; ?9_RI(a.}  
import java.io.*;
LxM.z1  
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hU}!:6G%[P  
public class FileAccessI implements Serializable{ 
<h$Nh0  
^k'?e"[gTs  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ]<pnHh+2A  
RandomAccessFile oSavedFile; 6a+w/IO3OU  
long nPos; ha;Xali ]  
Y=%SK8]Q;  
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public FileAccessI() throws IOException nTJ-1A7EP  
{ 3 e19l!B  
this("",0); uG|d7LS,%  
} ,+u.FQv~  
=1JS6~CTLN  
t Z_ni}  
public FileAccessI(String sName,long nPos) throws IOException sg.8Sd"]7  
{ Gj~1eS  
oSavedFile = new RandomAccessFile(sName,"rw"); n>)'!  
this.nPos = nPos; 0g-bApxz*&  
oSavedFile.seek(nPos); sG/mmZHYzr  
} 9(9+h]h+3  
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Vr1Wr%  
public synchronized int write(byte[] b,int nStart,int nLen) $a.!X8sHB.  
{ l1_Tr2A}7/  
int n = -1; UN~dzA~V  
try{ X>[x7t:  
oSavedFile.write(b,nStart,nLen); ZfpV=DU  
n = nLen; r((2.,\Z  
} >|)ia5#  
catch(IOException e) K/2k/\Jk[_  
{ d6$,iw@>^  
e.printStackTrace (); 6,ZfC<)  
} M~0A-*N  
}@6/sg  
2(-J9y|  
return n; %uuh+@/&yz  
} )JO#Z(  
ArFsr  
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} <Rs#y:  
}~?B
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u,zA^%  
/* x>>#<hOz[  
**SiteInfoBean.java qk;vn}auD]  
*/ -8L22t  
package NetFox; W"m\|x  
Z~g I)  
r'kUU]j9  
public class SiteInfoBean { cTA8F"UGD  
Dq#/Uw#  
(M1HNIM;(  
private String sSiteURL; //Site's URL
4%8}vCs  
private String sFilePath; //Saved File's Path DFgr,~  
private String sFileName; //Saved File's Name 7}r!&Eb  
private int nSplitter; //Count of Splited Downloading File TZ`@pDi  
egBjr?  
+GgJFBl  
public SiteInfoBean() AL%gqt]  
{//nSplitter的缺省值为5 E8TJ*ZU  
//default value of nSplitter is 5 U Hej5-B  
this("","","",5); yIab3/#`  
} 9uXuV$.  
U>q&p}z0H  
AN!MFsk  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) [DW}z  
{ 3)F9:Tzw1  
sSiteURL= sURL; "(@W^qF}d  
sFilePath = sPath; zW`Zmt\T2  
sFileName = sName; U($sH9,  
this.nSplitter = nSpiltter; hK!Z~  
:$bp4+
3>  
| HkLl^  
} M*DFtp<  
x=+R0ny  
@/S6P-4  
public String getSSiteURL() IrAc&Ehul  
{ '}3m('u  
return sSiteURL; T6X%.tR>`  
} 45Z"U<I,9  
8+m[ %5lu  
Qfhhceb6#J  
public void setSSiteURL(String value) U=?hT&w\S  
{ UbBo#(TZ)  
sSiteURL = value; GVFR^pzO  
} )$V&Nf  
vepZod}D  
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public String getSFilePath() x^UE4$oo  
{ so* lV  
return sFilePath; GZL{~7n  
} J`6X6YZ  
tMN^"sjf*  
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public void setSFilePath(String value) 0D;MW  
{ $rB20!  
sFilePath = value;
dx=\Pq  
} }3tbqFiH  
CgLS2  
2b+0}u>a  
public String getSFileName() /?POIn+0o  
{ "W_C%elg  
return sFileName; DVu_KT[Hd  
} +O<0q"E  
!B=Oc!e=K  
;WQ@dC  
public void setSFileName(String value) "J0,SFu:  
{ ; Q-f6)+&  
sFileName = value; fIrl?X']  
} aBPaC=g{HO  
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`O-LM
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public int getNSplitter() F{1;~Yg%  
{ P]bq9!{1  
return nSplitter; V\ud4  
} O[p;IG
`  
Evz;eobW/  
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public void setNSplitter(int nCount) E$z)$`"1  
{ 0> pOP  
nSplitter = nCount; B,sv! p+q5  
} 5xZ*U  
} u$%>/c
v  
,`7;S,f  
`aFy2x`3  
/* <1(:W[M  
**Utility.java 1vcI`8%S+u  
*/ KtWG2  
package NetFox; ]w _
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public class Utility { lO/<xSjNd  
By=/DVm)=  
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public Utility() zy(i]6  
{ 1'5I]D ec  
<B]\&  
&Mset^o  
} N0be=IO5#  
zcrLd={  
//线程睡眠 0B(<I?a/  
public static void sleep(int nSecond) myTz  
{ 0dKI+zg
r  
try{ kl.)A-6V  
Thread.sleep(nSecond);
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} aq[;[$w  
catch(Exception e) m178S3  
{ S7-ka{S  
e.printStackTrace (); Jji~MiMn  
} dhe?7r]u  
} 9wP_dJvb  
$!c)%qDq  
//日志 C24[brf  
public static void log(String sMsg) gY AXUM,  
{ .p%p_  
System.err.println(sMsg); ..qAE.%%  
} } d /5_X  
R9SJ;TsE  
'3Ir(]Wfd  
public static void log(int sMsg) q#W|*kL3  
{ ~je#gVoUR  
System.err.println(sMsg); .3Nd[+[  
} )rv5QH`i  
} 7<[p1C*B  
o+W5xHe^1  
.5I!h !  
/* 16MRLDhnD  
**TestMethod.java *loPwV8  
*/ G#/}
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package NetFox; -ea>}S  
8P r H"pI  
@NGK2J  
public class TestMethod { >W"gr]R<  
(#* 7LdZ  
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public TestMethod() W=M`Bkw{  
{ ///xx/weblogic60b2_win.exe <}b`2/wP  
try{ %sb)U~gP  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ZdHfZ3)dB  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); _[-+%RP  
SiteFileFetch fileFetch = new SiteFileFetch(bean); IM&2SSmYNH  
fileFetch.start(); 3vPb}  
} bs!N~,6h  
catch(Exception e){e.printStackTrace ();} SU;PmG4  
<v;;:RB6c  
I*R[8|  
} _aVrQ@9  
F)/}Q[o8  
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public static void main(String[] args) &P&LjHFK  
{ V6"
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new TestMethod(); I_@\O!<y}  
} 4g]Er<-P  
} ?Y2ZqI  
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