http断点续传简单实现（java)

/* /'yi!:FZFC  
**SiteFileFetch.java >~+'V.CNW  
*/ Cob<N'.  
package NetFox; #b^x!lR  
import java.io.*; 7v{X?86&  
import java.net.*; zB/)_AW  
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public class SiteFileFetch extends Thread { AK$h S
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SiteInfoBean siteInfoBean = null; //文件信息Bean ZUkrJ'  
long[] nStartPos; //开始位置 e*nT+Rp  
long[] nEndPos; //结束位置
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FileSplitterFetch[] fileSplitterFetch; //子线程对象 F9N/_H*+  
long nFileLength; //文件长度 Cp`>dtCd  
boolean bFirst = true; //是否第一次取文件 MfJs?N0  
boolean bStop = false; //停止标志 @Czj] t`  
File tmpFile; //文件下载的临时信息 GS<aXhk  
DataOutputStream output; //输出到文件的输出流 
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ,JLY oE+  
public SiteFileFetch(SiteInfoBean bean) throws IOException q
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{ tf:4}6P1  
siteInfoBean = bean; [@"7qKd1  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); k+D32]b@  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); J|'e.1v  
if(tmpFile.exists ()) r.JY88"  
{ $y2"Q,n+  
bFirst = false; 6Cdc?#&  
read_nPos(); 1vy*u  
} ~F{u4p
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else $ts%SDM  
{ RyAss0Sm^  
nStartPos = new long[bean.getNSplitter()]; K6 {0`'x  
nEndPos = new long[bean.getNSplitter()]; )P)Zds@F  
} | e&v;48  
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} ^Z6N&s#6  
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public void run() mbZS J  
{ RD$"ft
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//获得文件长度 !awsQ!e|  
//分割文件 !yfQ^a_
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//实例FileSplitterFetch sF+mfoMtG  
//启动FileSplitterFetch线程 >$%rsc}^  
//等待子线程返回 Os9;;^k  
try{ D>HX1LV  
if(bFirst) qi ;X_\v  
{ vvsQf
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nFileLength = getFileSize(); _&]B  
if(nFileLength == -1) PX5K-|R  
{ Dej2-Y  
System.err.println("File Length is not known!"); & rsNB:!  
} 8/tvS8I#y  
else if(nFileLength == -2) zG[GyyAQ  
{ vv9=g*"j  
System.err.println("File is not access!"); qYwEPGa\  
} G#|`Bjv"aP  
else 3lZ5N@z69  
{ ]O\m(of R  
for(int i=0;i<nStartPos.length;i++) ;:^^Qfp  
{ 1=9M@r~ ^  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); CP%?,\  
} bPe|/wp  
for(int i=0;i<nEndPos.length-1;i++) 5LIbHSK  
{ gM5`UH|  
nEndPos = nStartPos[i+1]; e1 yvvi  
} mvCH$}w8&  
nEndPos[nEndPos.length-1] = nFileLength; NrNxI'MG  
} ++Z
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} &~6W!w  
F5Xj}`}bq  
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//启动子线程 03{pxI
 
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; O%Mi`\W@  
for(int i=0;i<nStartPos.length;i++) (|
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{ L^7"I 4=(D  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), :*/'W5iM  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), a$~pAy5C  
nStartPos,nEndPos,i); Z0(}doh  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Hxw 7Q?F  
fileSplitterFetch.start(); j$he5^GC  
} ;QiSz=DyA  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), iaq+#k@V  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); |KC!6<}T~9  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 6dzY9  
nEndPos = " + nFileLength); ?xb4y=P7  
// fileSplitterFetch[nPos.length-1].start(); '5*8'.4Sy  
Q&X#(3&'  
!:N&tuJEv  
//等待子线程结束 z-Ndv;:  
//int count = 0; F/QRgXV  
//是否结束while循环 @5C!`:f  
boolean breakWhile = false; [q%Rx!L  
LXGlG  
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while(!bStop) Lwzk<+>w^  
{ +im>|  
write_nPos(); ZbZCW:8>k  
Utility.sleep(500); zS6oz=  
breakWhile = true; HZ+l){u  
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for(int i=0;i<nStartPos.length;i++) `E4+#_ v  
{ Q)$RE{*-  
if(!fileSplitterFetch.bDownOver) 1 po.Cmx  
{ t}!Y}D  
breakWhile = false; {zri6P+s  
break; pI>[^7  
} Q.$|TbVfds  
} v'vYNh  
if(breakWhile) VY@6!
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break; saj%[Gsy  
`F^~*FnR,B  
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//count++; Z<Pf[C  
//if(count>4) qoo+=eh!  
// siteStop(); ~h<<-c  
} T=kR!Gx  
?KKu1~a_  
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System.err.println("文件下载结束！"); d hp-XI
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} FthrI  
catch(Exception e){e.printStackTrace ();} h3<L,Olp  
} -!C9x?gNY  
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//获得文件长度 3 cb$g  
public long getFileSize() 65>1f  
{ ;4!,
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int nFileLength = -1; |k:ecw  
try{ X>$s>})Y  
URL url = new URL(siteInfoBean.getSSiteURL()); REj<2Lo  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); \a.^5g  
httpConnection.setRequestProperty("User-Agent","NetFox"); [
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int responseCode=httpConnection.getResponseCode(); [\rnJ lE  
if(responseCode>=400) ]'[(MH"  
{ RXbhuI  
processErrorCode(responseCode); )qL
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return -2; //-2 represent access is error mk'$ |2O  
} g9XAUZe  
bh~"LQS1  
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String sHeader; H E'1Wa0r  
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for(int i=1;;i++) RM(MCle}  
{ jmH=W)  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); U=G}@Y  
//Utility.log(in.readLine()); ?C6DK{S(  
sHeader=httpConnection.getHeaderFieldKey(i); n$03##pf  
if(sHeader!=null) b)e';M  
{ h,(f3Ik0O  
if(sHeader.equals("Content-Length")) ^s;xLGl]  
{ YWXY4*G  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); AB1.l hR  
break; Wj}PtQ%lp/  
} 
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} |RA|nu   
else &-hz&/A,  
break; ayR;|S  
} cj5;XK  
} !gKz=-C  
catch(IOException e){e.printStackTrace ();} =rB=! ;  
catch(Exception e){e.printStackTrace ();} R'Uw
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\{RMj"w:  
Utility.log(nFileLength); >cV^f6fH  
] C&AU[U*  
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return nFileLength; 9!kH:Az[p  
} xyvG+K&  
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//保存下载信息（文件指针位置） O7x'q<PFU  
private void write_nPos() jO9w7u6  
{ ku&m)'  
try{ {f12&t  
output = new DataOutputStream(new FileOutputStream(tmpFile)); M< 1rQW'  
output.writeInt(nStartPos.length); DJGq=*  
for(int i=0;i<nStartPos.length;i++) %_>+K;<  
{ S Y7'S#  
// output.writeLong(nPos); y. A]un1  
output.writeLong(fileSplitterFetch.nStartPos); $UX^$gG  
output.writeLong(fileSplitterFetch.nEndPos); ,Q2?Z:l  
} OZ9ud ]@\  
output.close(); s&gzv=v  
} ifYC&5}SI  
catch(IOException e){e.printStackTrace ();} Vo; B#lK  
catch(Exception e){e.printStackTrace ();} p`CVq`k  
} @TWtM#  
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//读取保存的下载信息（文件指针位置） jr=>L:  
private void read_nPos() (oiF05n h  
{ OSDx  
try{ >,#73
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DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ,];4+&|8kW  
int nCount = input.readInt(); F-g7*  
nStartPos = new long[nCount]; -2`D(xC  
nEndPos = new long[nCount]; <.N337!  
for(int i=0;i<nStartPos.length;i++) Y2B",v"  
{ M }H7`
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nStartPos = input.readLong(); 2!y%nkO*  
nEndPos = input.readLong(); vvDaL$  
} 
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input.close(); i,h)  
} eLd7|*|  
catch(IOException e){e.printStackTrace ();} 4YmN3i  
catch(Exception e){e.printStackTrace ();} R DAihq  
} {TWgR2?{C  
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private void processErrorCode(int nErrorCode) 3H'+7
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{ 5YQq*$|'+  
System.err.println("Error Code : " + nErrorCode); 9tt0_*UX  
} Z#i5=,Bk  
$:aKb#l)  
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//停止文件下载 #;#r4sJwU  
public void siteStop() L+b"d3!G&%  
{ F9Bj$`#)  
bStop = true; RwR.*?#  
for(int i=0;i<nStartPos.length;i++) G.}Ex!8R7_  
fileSplitterFetch.splitterStop(); _s&sA2r<  
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-nvK*rn>}  
} :M%s:,]R  
} hny):59f  
//负责部分文件的抓取 lZq`,E_L  
**FileSplitterFetch.java vcsMU|GGh  
*/ @6~OQN  
package NetFox; 8r 4 L4  
qZ8V/  
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import java.io.*; u{@b_75Y  
import java.net.*; unUCn5hJ=  
7fB:wPlG;  
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public class FileSplitterFetch extends Thread { =h"*1`  
o3mxtE]  
9m:qQ1[\  
String sURL; //File URL S(5aJ[7Zm  
long nStartPos; //File Snippet Start Position OcB
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long nEndPos; //File Snippet End Position r$7D;>*O{  
int nThreadID; //Thread's ID p(5'|eqBV  
boolean bDownOver = false; //Downing is over Hsoe?kUHF  
boolean bStop = false; //Stop identical }k-rOi'jL  
FileAccessI fileAccessI = null; //File Access interface SLiQHWw*J  
b,7@)sZ*  
9=-!~_'1-  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException @+S5"W  
{ |0wUOs*5  
this.sURL = sURL; l*l(QvN_  
this.nStartPos = nStart; [P*w$Hn  
this.nEndPos = nEnd; TAbC-T.EV  
nThreadID = id; bN#)F    
fileAccessI = new FileAccessI(sName,nStartPos);//定位 (:p&[HNuN  
} P9wx`x""k  
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public void run() ^<@9ph  
{ #Moju  
while(nStartPos < nEndPos && !bStop) )I`6XG  
{ <.d0GD`^  

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#hBDOXHPf  
try{ W .c:Pulg  
URL url = new URL(sURL); $X%w9le  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 41595x:  
httpConnection.setRequestProperty("User-Agent","NetFox"); Jk.Ec)w  
String sProperty = "bytes="+nStartPos+"-"; xY/ S;dE  
httpConnection.setRequestProperty("RANGE",sProperty); U 9?!|h;7  
Utility.log(sProperty); tcg sXB/t  
0 w"&9+kV  
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InputStream input = httpConnection.getInputStream(); ya9V+/i7T_  
//logResponseHead(httpConnection); |!\(eLR9>  
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byte[] b = new byte[1024]; xl(];&A3  
int nRead; GlDl0P,*r  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) vM}oxhQ$n  
{ !5~{?sr>  
nStartPos += fileAccessI.write(b,0,nRead); 4g.y$  
//if(nThreadID == 1) :EK.&%2  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); LWb5C{  
} T/^ /U6JB  
V9 pKbX  
/CtR|~wL  
Utility.log("Thread " + nThreadID + " is over!"); rZ~.tT|(  
bDownOver = true; F1@gYNbI,  
//nPos = fileAccessI.write (b,0,nRead); #du!tx ( _  
} (aX5VB**  
catch(Exception e){e.printStackTrace ();} zl: 5_u=T  
} W@^O'&3d  
} H1,;Xrm  
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//打印回应的头信息 Os?`!1-  
public void logResponseHead(HttpURLConnection con) 3N)
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{ 3B(6^iS  
for(int i=1;;i++) \advFKN  
{ zL@ZNH  
String header=con.getHeaderFieldKey(i); 29?{QJb  
if(header!=null) iBy:HH  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 4Lx#5}P  
Utility.log(header+" : "+con.getHeaderField(header)); /\-qz$  
else k,xY\r$  
break; _u^ S[  
} )g9&fGYf  
} i;1aobG  
 R1YRqk  
\e5bxc  
public void splitterStop() Ly?gpOqu5  
{ TR8
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bStop = true; {XMF26C#  
} /++CwRz@Gm  
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} 2$^n@<uZ@  
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8_MR7'C1hi  
/* ~+{OSx<S  
**FileAccess.java 7m6@]S6  
*//文件访问(定位，写) 'AX/?Srd  
package NetFox; +$:bzo_u  
import java.io.*; CT@JNG$<"  
.kSx>3  
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public class FileAccessI implements Serializable{ Y"&&=M#  
C>q,c3s5  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 V:rq}F}  
RandomAccessFile oSavedFile; **V^8'W<  
long nPos; ">}l8MA  
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public FileAccessI() throws IOException /wB<1b"  
{ @,D 3$P8}  
this("",0); K@P5]}'#  
} )8ejT6r  
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9 veq  
public FileAccessI(String sName,long nPos) throws IOException 7hq*+e  
{ 66x>*  
oSavedFile = new RandomAccessFile(sName,"rw"); +A 6xY  
this.nPos = nPos; hPhNDmL#3  
oSavedFile.seek(nPos); `MAluu+b  
} >-YP

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g&y'#,'Q~,  
public synchronized int write(byte[] b,int nStart,int nLen) )6#dxb9  
{ e%w>QN`  
int n = -1; F#KO!\iA+  
try{ <N11$t&_  
oSavedFile.write(b,nStart,nLen); "q(#,,_  
n = nLen; klduJT >  
} T8
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catch(IOException e) 2]n"7Z8(v8  
{ xmxfXW  
e.printStackTrace (); @.f@N
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} A0sydUc  
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[vkz<sL"  
return n; M7&u_Cn?  
} E~5r8gM,0  
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} je1f\N45  
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/* jW5n^Y)  
**SiteInfoBean.java sw{,l"]<  
*/ 76a+|TzR  
package NetFox; vr<6j/ty  
$}0q=Lg%wv  
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public class SiteInfoBean { FN5*pVD;<  
O^v^GG=e;C  
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private String sSiteURL; //Site's URL uM,bO*/f  
private String sFilePath; //Saved File's Path ((wG K|d  
private String sFileName; //Saved File's Name S+>1yvr),  
private int nSplitter; //Count of Splited Downloading File Bi9b"*LN  
w*`5b!+/  
ru,]!YPJE2  
public SiteInfoBean() 5;5;bBo~  
{//nSplitter的缺省值为5 XQ&iV7   
//default value of nSplitter is 5 O;c;>x_dA  
this("","","",5); Ym+k \h  
} mRB-}  
@BWroNg{  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) {7&(2Z]z  
{ :nYl]Rm  
sSiteURL= sURL; lj$\2B  
sFilePath = sPath; ab8uY.j  
sFileName = sName; 1TbY,3W  
this.nSplitter = nSpiltter; VyH'7_aU  
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} <d~P
;R(@  
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public String getSSiteURL() sJ)XoK syW  
{ p_S8m|%  
return sSiteURL; MVU5+wX  
} ]5W0zNb*  
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v;"
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public void setSSiteURL(String value) vt}+d StUm  
{ BsiHVr  
sSiteURL = value; Xk%92Pto  
} g#qt<d}j  
@ROMHMd}  
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public String getSFilePath() wvsKnYKX  
{ Ub=g<MYHV  
return sFilePath; Cw]&B  
} /gT$d2{  
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public void setSFilePath(String value) +c5z-X$^]  
{ DK 4 8  
sFilePath = value; TB9{e!4  
} ,-^Grmr4M  
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public String getSFileName() }
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{ ;Ut0tm  
return sFileName; xWlj.Tjt}  
} "']I.  
@sRRcP~  
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public void setSFileName(String value) ?_q e 2R.  
{ `oP :F[B  
sFileName = value; ]2\|<.  
} _]8FCO  
j#d=V@=a  
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public int getNSplitter() tZmo= 3+:  
{ <a7y]Py  
return nSplitter; x>vC;E${"  
} 8 hx4N  
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public void setNSplitter(int nCount) v'uWmL7C  
{ j:K>3?   
nSplitter = nCount; $j*%}x~[  
} %Cbqi.iuQ  
} |k$^RU<OF  
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!Kr|04Qp#x  
/* Q!8AFLff4  
**Utility.java \}Fx''  
*/ U 2am1}  
package NetFox; @qk$ 6X  
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public class Utility { nN1\  
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p2 u*{k{  
public Utility() 9}4P%>_  
{ ! iuDmL  
}SYR)eE\  
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} |kJ'FZZd  
!_CBf#0  
//线程睡眠 "L^]a$&  
public static void sleep(int nSecond) QcJ?1GwA"  
{ =.`(KXT  
try{ .lnyn|MVb  
Thread.sleep(nSecond); S]&f+g}&w  
} sy`@q<h(  
catch(Exception e) o1<Y#db[  
{ 4ti\;55{W  
e.printStackTrace (); X!Ag7^E  
} P{j2'gg3  
} g&eIfm  
S}6Ty2.\  
//日志 ) =-$>75Z  
public static void log(String sMsg) t}L kl(  
{ 4FURm@C6  
System.err.println(sMsg); Nn<TPT[,  
} wdg,dk9e$  
\d$fi*{  
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public static void log(int sMsg) |#9Nu9ak  
{ C(-wA  
System.err.println(sMsg); r >bMx~a]  
} )H@"S]?7i"  
} Vb^P{F  
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/* %(lr.9.]H  
**TestMethod.java R-8>,  
*/ B].
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package NetFox; nmIos]B  
o2M+=O@  
~ 8L]!OQ9=  
public class TestMethod { T DOOq;+  
lId}sf  
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public TestMethod() D5lzrpg_e  
{ ///xx/weblogic60b2_win.exe #1fT\aP  
try{ t;005]'Mp  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); )e&U'Fx  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); n;&08M5an}  
SiteFileFetch fileFetch = new SiteFileFetch(bean); EB R,j_  
fileFetch.start(); ,z<J`n  
} E4;vC ?K{  
catch(Exception e){e.printStackTrace ();} 8~*<s5H  
|@'/F#T  
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} 8@;|x2=y  
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public static void main(String[] args) +tOmKY  
{ j9Qd 45  
new TestMethod(); <12ia"}  
} ?VCdT`6=  
} U9w0kcUw#J  
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