http断点续传简单实现（java)

/* Ev,b5KelD  
**SiteFileFetch.java ShJBOaE; -  
*/ no7Q%O9  
package NetFox; A<[BR*n  
import java.io.*; 5XinZ~  
import java.net.*; o| 9Mj71  
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public class SiteFileFetch extends Thread { c<5(c%
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 ~D_Wqr  
SiteInfoBean siteInfoBean = null; //文件信息Bean 
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long[] nStartPos; //开始位置 (XQ:f|(  
long[] nEndPos; //结束位置 {3K`yDF  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 :-e[$6}S  
long nFileLength; //文件长度 %B04|Q  
boolean bFirst = true; //是否第一次取文件 &'W ~~ir  
boolean bStop = false; //停止标志 oZw#]Q@  
File tmpFile; //文件下载的临时信息 8GT4U5c ;  
DataOutputStream output; //输出到文件的输出流 PPj%
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 6yedl0@wa!  
public SiteFileFetch(SiteInfoBean bean) throws IOException h&<>nK   
{ SH;:bLk_  
siteInfoBean = bean; EsjZ;D,c(  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); #~`d ;MC  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); TH? wXd\  
if(tmpFile.exists ()) C*Wyw]:r  
{ Wrs6t  
bFirst = false; ;I]$N]8YI  
read_nPos(); H1hADn  
} Z1R{'@Y0Z  
else =90)=Pxd  
{ M Jtn)gXb  
nStartPos = new long[bean.getNSplitter()]; l vfplA  
nEndPos = new long[bean.getNSplitter()]; f<*-;  
} @hOT< Uo  
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} Lo5CVl
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7  
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public void run() R)'[Tt`#R  
{ ]TSzT"_r~~  
//获得文件长度 DcmRvi)&6  
//分割文件 )X'ln  
//实例FileSplitterFetch K# BZ Jcb  
//启动FileSplitterFetch线程 QR h %S{  
//等待子线程返回 mLH,6rO9  
try{ x1`zD*{  
if(bFirst) =|
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{ M6"a w6  
nFileLength = getFileSize(); O*m9qF<  
if(nFileLength == -1) dS;Ui]/J  
{ i} ?\K>BWq  
System.err.println("File Length is not known!"); lcEUK  
} 7 MG<!U  
else if(nFileLength == -2) 
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{ +=#@1k~  
System.err.println("File is not access!"); .*nr3dY  
} {lNG:o  
else /H :Bu  
{ Ed>n/)Sm  
for(int i=0;i<nStartPos.length;i++) |!uC [=  
{ Hzojv<c  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); I
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} A\QrawBp0l  
for(int i=0;i<nEndPos.length-1;i++) =$
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{ ?xb2jZ/0X  
nEndPos = nStartPos[i+1]; tW"s^r=95  
} lfyij[6q+  
nEndPos[nEndPos.length-1] = nFileLength; x(y=.4Yf+  
} xH{V.n&v  
} 7!^Zsp^+  
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]
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//启动子线程 T,5(JP(h3  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; *DPKV$  
for(int i=0;i<nStartPos.length;i++) /|,:'W%U  
{ LqoH]AcN  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), nVGWJ3  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), smat6p[  
nStartPos,nEndPos,i); A5%cgr
% 6  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos);
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fileSplitterFetch.start(); `a]feAl  
} CAbT9Wz&  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Pt?d+aBtV  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); $QJ,V~  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 4\(|V fy  
nEndPos = " + nFileLength); ,Zb_Pu   
// fileSplitterFetch[nPos.length-1].start(); .5+5ca  
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vz`r !xj)  
//等待子线程结束 s^ K:cz  
//int count = 0; J9XV:)Yv#  
//是否结束while循环 mZ4I}_\,  
boolean breakWhile = false; yvV]|B@sO  
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while(!bStop) 2[5z6oG  
{ trM)&aQto  
write_nPos(); ./Wi(p{F  
Utility.sleep(500); <*5`TE0J  
breakWhile = true; Rmh u"N/q  
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for(int i=0;i<nStartPos.length;i++) HOlMj!.  
{ 4nGr?%>  
if(!fileSplitterFetch.bDownOver) zH1ChgF=}  
{ sH\h{^  
breakWhile = false; d6{
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break; y\}
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} l#;o^H i  
} @rxfOc0J#  
if(breakWhile) r9$7P?zm  
break; 1zc-$B`t
 
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//count++; - xQJY)  
//if(count>4) 9H,Ec,.  
// siteStop(); u
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} 0
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System.err.println("文件下载结束！"); y<n<uZ;  
} ej{7)#  
catch(Exception e){e.printStackTrace ();} Nj;G%KAP  
} gclw>((5  
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//获得文件长度 GM>Ms!Y  
public long getFileSize() cK6IyJx-  
{ 1iIag}?p  
int nFileLength = -1; mY/x|)MmM  
try{ #GA6vJ4^s  
URL url = new URL(siteInfoBean.getSSiteURL()); H"%SzU  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ~
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httpConnection.setRequestProperty("User-Agent","NetFox"); =.f<"P51k  
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int responseCode=httpConnection.getResponseCode(); =-8y=  
if(responseCode>=400) )GF>]|CG  
{ {^SHIL  
processErrorCode(responseCode); YOY{f:ew  
return -2; //-2 represent access is error n<66 7 <  
} ,: 4+hJ<q  
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String sHeader; R9O[`~BA2  
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for(int i=1;;i++) /_CSRi&
 
{ L$s;tJ   
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); h|Udw3N1L  
//Utility.log(in.readLine()); i`HXBq!|w  
sHeader=httpConnection.getHeaderFieldKey(i); .GNl31f0  
if(sHeader!=null) pPtw(5bH  
{ ~h6aTN  
if(sHeader.equals("Content-Length")) $sBje*;  
{ TH#5j.uUs  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); %<Kw  
break; N.qS;%*o{e  
} y/yg-\/XF  
} e6igx  
else "ba>.h,#'  
break; y|[YEY U)  
} L'$;;eM4  
} rH5'+x K  
catch(IOException e){e.printStackTrace ();} [wR x)F"  
catch(Exception e){e.printStackTrace ();} X1;ljX  
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Utility.log(nFileLength); C4/p5J  
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return nFileLength; \' ;zD-MX  
} l/o 4bkV  
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//保存下载信息（文件指针位置） O^yDb  
private void write_nPos() @$%[D`Wa<  
{ Zi~-m]9U  
try{ o"./  
output = new DataOutputStream(new FileOutputStream(tmpFile)); n8vteGQ  
output.writeInt(nStartPos.length); p:q?8+W-r  
for(int i=0;i<nStartPos.length;i++) $Hbd:1%i {  
{ VA0p1AD  
// output.writeLong(nPos); @8xa"Dc  
output.writeLong(fileSplitterFetch.nStartPos); XZ!^kftyW  
output.writeLong(fileSplitterFetch.nEndPos); ,zU7UL^I  
} u+/1ryp  
output.close(); sFWH*kdP?  
} CPS1b  
catch(IOException e){e.printStackTrace ();} t+`>zux5(T  
catch(Exception e){e.printStackTrace ();} NgPY/R>  
} 1>e%(k2w%  
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//读取保存的下载信息（文件指针位置） @-F[3`HeA  
private void read_nPos() lL{1wCsl  
{ 5fVm392+  
try{ #K_E/~  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); q%xq\L.  
int nCount = input.readInt(); _|%l) KO  
nStartPos = new long[nCount]; " .:b43Z  
nEndPos = new long[nCount]; %V3xO%  
for(int i=0;i<nStartPos.length;i++) *{e?%!Q  
{ C.}Vm};M  
nStartPos = input.readLong(); }|!9aojr  
nEndPos = input.readLong(); /~B\1  
} = 7TK&  
input.close(); e[AwR?=  
} xfJ&11fG2  
catch(IOException e){e.printStackTrace ();} Z>+Tzvfud  
catch(Exception e){e.printStackTrace ();} ra*(.<&  
} TScI_8c>  
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private void processErrorCode(int nErrorCode) D%NVqk|  
{ Ko|p&-Z;  
System.err.println("Error Code : " + nErrorCode); #3m7`}c  
} 't:s6  
#>/stU-  
m^rrbU+HM?  
//停止文件下载 k%S;N{Qh@  
public void siteStop() K4>nBvZ?v  
{ mfpL?N  
bStop = true; _wMYA8n  
for(int i=0;i<nStartPos.length;i++) KJ&~z? X  
fileSplitterFetch.splitterStop(); rAZsVnk?  
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} DeTD.)pS  
} &z"sT*3  
//负责部分文件的抓取 |w7D&p$  
**FileSplitterFetch.java ~'aK[3  
*/ ek3,ss3  
package NetFox; ^w*$qzESy  
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import java.io.*; Oe^oigcM  
import java.net.*; vx&jI$t8  
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public class FileSplitterFetch extends Thread { +W-,74A  
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String sURL; //File URL V\(p6:1(6K  
long nStartPos; //File Snippet Start Position Wk"\aoX"E  
long nEndPos; //File Snippet End Position [C TR8  
int nThreadID; //Thread's ID OY>0qj  
boolean bDownOver = false; //Downing is over KKLW-V\6K  
boolean bStop = false; //Stop identical Rw9 *!<Izt  
FileAccessI fileAccessI = null; //File Access interface `LID*uD;_  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Hlg Q0qb  
{ wK[Xm'QTPJ  
this.sURL = sURL; xf?6_=  
this.nStartPos = nStart; t:h~p-&QB  
this.nEndPos = nEnd; qr~=S  
nThreadID = id; }1/`<m  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ;:)?@IuSy  
} &InMI#0mV  
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public void run() j;+!BKWy4  
{ EN!Q]O|  
while(nStartPos < nEndPos && !bStop) :',Q6j(s  
{ ~dO&e=6Hk  
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try{ ,n&e,I  
URL url = new URL(sURL); B- VhUS  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); qAF.i^  
httpConnection.setRequestProperty("User-Agent","NetFox"); 9J!@,Zsh  
String sProperty = "bytes="+nStartPos+"-"; GG@&jcp7  
httpConnection.setRequestProperty("RANGE",sProperty); *7yu&a8  
Utility.log(sProperty); JZS#Q\JN  
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;| :^zo  
InputStream input = httpConnection.getInputStream();
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//logResponseHead(httpConnection); w 
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byte[] b = new byte[1024]; 9se,c  
int nRead; 6*:m
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while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) \?9{H6<=  
{ $M(ZKS3,j  
nStartPos += fileAccessI.write(b,0,nRead); R3dCw:\O+Z  
//if(nThreadID == 1) %HNe"7gk  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 6_w;dnVA  
} FLI0C  
)Z2l*fV  
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Utility.log("Thread " + nThreadID + " is over!"); ?+WSYg0  
bDownOver = true; BP7&wd  
//nPos = fileAccessI.write (b,0,nRead); ?_+h+{/@B  
} 3]iBX`Ni  
catch(Exception e){e.printStackTrace ();} !PFc)J  
} #)r  
} {J}Zv5  
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q-;z!iq|!  
//打印回应的头信息 C6XZZ  
public void logResponseHead(HttpURLConnection con) ;6?VkF  
{ \R0&*cnmo  
for(int i=1;;i++) a_pNFe  
{ 9Xu O\+z  
String header=con.getHeaderFieldKey(i); *{y/wgX  
if(header!=null) >J \}&!8,  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); `XJU$c  
Utility.log(header+" : "+con.getHeaderField(header)); r3hUa4^97  
else i8tH0w/(M  
break; $g?`yE(K  
} 3%JPJuNVw  
} mR3km1T  
7|"gMw/  
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public void splitterStop() *)2&gQ&%+  
{ (RL5L=,u  
bStop = true; #SzCd&hI  
} S$Cht6m  
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} ^h:%%\2  
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/* 5DHFxym'  
**FileAccess.java Dm"@59x  
*//文件访问(定位，写) P7||d@VW,  
package NetFox; AvN\^ &G  
import java.io.*; FE`:1  
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public class FileAccessI implements Serializable{ !]
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5jpb`Axj#  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 *:q,G  
RandomAccessFile oSavedFile; p&:(D=pIu  
long nPos; R
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public FileAccessI() throws IOException s5s'$|h"  
{ Z"# /,?|3@  
this("",0); 6+MZ39x
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} gZFtV  
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public FileAccessI(String sName,long nPos) throws IOException IXmtjRv5  
{ H'L~8>  
oSavedFile = new RandomAccessFile(sName,"rw"); )<D(Mb2p|  
this.nPos = nPos; r&G
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oSavedFile.seek(nPos); }#[MV+D  
} 7yU<!p?(  
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public synchronized int write(byte[] b,int nStart,int nLen) | 'SqG}h  
{ -N')LY  
int n = -1; l>i<J1  
try{ QsaaA MGY  
oSavedFile.write(b,nStart,nLen); *EZ'S+wR  
n = nLen; v.08,P
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} Y6|8;2E  
catch(IOException e) p~T)Af<(  
{ D3^Yc:[_@  
e.printStackTrace (); f?iQ0wv)  
} X0=#e54  
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!,#42TY*X  
return n; ::\7s  
} (W<n<sl:-  
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} 2BU%4IG  
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1k5o?'3&  
/* u0;FQr2  
**SiteInfoBean.java  xZ*.@Pkr  
*/ 7R 40t3  
package NetFox; tFvc~zz9  
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public class SiteInfoBean { cG|ihG5)  
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private String sSiteURL; //Site's URL ,8KD-"l^g  
private String sFilePath; //Saved File's Path 0L "+,  
private String sFileName; //Saved File's Name PKoB~wLH  
private int nSplitter; //Count of Splited Downloading File <z3:*=!  
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public SiteInfoBean() }";\8  
{//nSplitter的缺省值为5 y/>]6Pj  
//default value of nSplitter is 5 N798("  
this("","","",5); [@U2a$k+d  
} vHY."$|H  
6.z8!4fpl  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) \0'7p-
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{ zV(F9}^  
sSiteURL= sURL; *&b~cyC  
sFilePath = sPath; aZ%
  
sFileName = sName; o2cZ  
this.nSplitter = nSpiltter; o}XbFLn  
`%lgT+~T  
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} ?fB}9(
6  
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public String getSSiteURL() "o +" Jd  
{ #C+""qm  
return sSiteURL; 0hTv0#j#  
} >&K1+FSmyJ  
FFH9$>A  
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public void setSSiteURL(String value) Mf0XQ3n`H  
{ )q?z"F|  
sSiteURL = value; c;w%R8z  
} :NL.#!>/  
%m:T?![XO  
T&_!AjH  
public String getSFilePath() CwKo'PAJ  
{ xm@vx}O:  
return sFilePath;  fL9R{=I%  
}  '&/"_  
4%Q8>mEvT  
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public void setSFilePath(String value) Fg8i} >w  
{ Jsee8^_~  
sFilePath = value; |Uz?i7z  
} \Uun2.K  
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public String getSFileName() rs$sAa*f  
{ K252l,;|  
return sFileName; $42C4I*E  
} ;eznONNF  
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public void setSFileName(String value) 2.=3:q!H<%  
{ rA9BY :N@  
sFileName = value; (\ `knsE!  
} dQ97O{O:i  
!br0s(|  
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public int getNSplitter() &DdFK.lt  
{ ,5jE9  
return nSplitter; "j5b$T0P>  
} _@3?yv~ D  
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public void setNSplitter(int nCount) 7<V(lX.{  
{ Ic4>kKh  
nSplitter = nCount; Zfyr&]"  
} jIx5_lFe  
} cT abZc  
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/* @&;y0N1xo  
**Utility.java k~WX6rEJ  
*/ T)B
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package NetFox; [xT2c.2__J  
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public class Utility { {l=!  
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public Utility() T$/6qZew  
{ ~
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O@jW&-;  
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} T69'ta32V  
HVzG }r(J  
//线程睡眠 'ypJGm  
public static void sleep(int nSecond) SS@F:5),  
{ 4CO:*qG)o  
try{ (9x8,f0z  
Thread.sleep(nSecond); )P\Vd #  
} ,mH2S/<}S  
catch(Exception e) ]Lq9Ompf(t  
{ kKnz F  
e.printStackTrace (); YK#bzu ,!  
} }?xu/C  
} (v*$ExF  
9,y*kC  
//日志 #"%=7(

 
public static void log(String sMsg) Hk%m`|Z  
{ O.S(H1z<G  
System.err.println(sMsg); `i0RLGze  
} '7}s25[{\  
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public static void log(int sMsg) SlvQ)
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{ H)1< ;{:  
System.err.println(sMsg); xfw)0S  
} 6bCC6G  
} |S#)[83*3  
O G#By6O  
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/* M
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**TestMethod.java eS9/-Y  
*/ 'Syq!=,  
package NetFox; rgheq<B:  
weC$\st:D  
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public class TestMethod { {zhN>n_  
i[)H!%RV*  
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public TestMethod() }ex2tkz  
{ ///xx/weblogic60b2_win.exe tv,iCV  
try{ u(\O  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); a2fV0d6*l  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); *,!6#Z7  
SiteFileFetch fileFetch = new SiteFileFetch(bean); $d.UF!s  
fileFetch.start(); 2w93 ~j  
} 'Uqz,  
catch(Exception e){e.printStackTrace ();} R+IT)2  
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} n?vrsqmZ  
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public static void main(String[] args) K:/%7A_{  
{ eZs34${fN  
new TestMethod(); xS]=WO*  
} ,o\vumx  
} !u@e^J{Ao  
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