http断点续传简单实现（java)

/* 
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**SiteFileFetch.java _S2^;n?  
*/ O^Vy"8Ji}y  
package NetFox; M`P]cX)x  
import java.io.*; n&m?Bu
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import java.net.*; (}X?v`Y^W  
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public class SiteFileFetch extends Thread { mBZDl4 '  
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SiteInfoBean siteInfoBean = null; //文件信息Bean oPu|Q^I=  
long[] nStartPos; //开始位置 @
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long[] nEndPos; //结束位置 ~}
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FileSplitterFetch[] fileSplitterFetch; //子线程对象 SxZ^ "\H  
long nFileLength; //文件长度 ]KK ZbEO  
boolean bFirst = true; //是否第一次取文件 G0QXf  
boolean bStop = false; //停止标志 DIqT>HHZ  
File tmpFile; //文件下载的临时信息 pOVghllO  
DataOutputStream output; //输出到文件的输出流 fuD1U}c  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） QHzX 5$IM  
public SiteFileFetch(SiteInfoBean bean) throws IOException xbrmPGpW$  
{ StZRc\k  
siteInfoBean = bean; X;6r$   
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); to!W={S<ol  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); N9=r#![>,  
if(tmpFile.exists ()) dA)4(0o8fD  
{ U=i8>6V  
bFirst = false; qi SEnRG.  
read_nPos(); =3sldKL&F  
} /GuSIZg"_  
else aT1CpY=T|.  
{ ah/6;,T  
nStartPos = new long[bean.getNSplitter()]; Hx
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nEndPos = new long[bean.getNSplitter()]; vYSetAdv  
} d0A\#H_&  
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} -hVv  
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public void run() bN4&\d*u#  
{ 7 xp1\j0  
//获得文件长度 )YnI!v2T  
//分割文件 @x=BJuUuX  
//实例FileSplitterFetch loC5o|Wh  
//启动FileSplitterFetch线程 )qyx|D  
//等待子线程返回 ~f=6?5.wa  
try{ dx13vZ3[U  
if(bFirst) XW~ BEa  
{ tT* W5  
nFileLength = getFileSize(); YZBzv2'\x  
if(nFileLength == -1) qsft*&  
{ nrS[7~  
System.err.println("File Length is not known!"); LN.Bd,  
} *K}z@a_  
else if(nFileLength == -2) :nKsZ1bX  
{ d
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System.err.println("File is not access!"); V8nz-DL{  
} g^z5fFLg/8  
else Tw}?(\ya  
{ D0#T-B\#  
for(int i=0;i<nStartPos.length;i++) 2%5^Fi  
{ ?79SPp)oo  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); !qTpQ5Dm  
} n~,]KdU]  
for(int i=0;i<nEndPos.length-1;i++) 8tV=fSHd  
{ EFRZ% Y  
nEndPos = nStartPos[i+1]; B;z>Dd,Y_x  
} #0?"J)  
nEndPos[nEndPos.length-1] = nFileLength; 8g[(nxI~  
} +(z_"[l"  
} [>$\s=` h  
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//启动子线程 -t%{"y  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Iuu<2#gb8"  
for(int i=0;i<nStartPos.length;i++) 4T==A#
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{ uG=t?C6  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ^J#?hHz  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ;/?Z<[B  
nStartPos,nEndPos,i); >}<29Ii  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); |t&G&)~:  
fileSplitterFetch.start(); 0NCOz(L/  
} bl" (<TM  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 9<t9a f\.>  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); J|gdO+  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Ei{(  
nEndPos = " + nFileLength); lruF96C/Y  
// fileSplitterFetch[nPos.length-1].start(); VQy9Y  
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//等待子线程结束 OX)#F'Sl}  
//int count = 0; N+\oFbE  
//是否结束while循环 < v|%K.yd  
boolean breakWhile = false; u8-a-k5<  
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while(!bStop) ]5} -y3  
{ +,&m7L  
write_nPos(); A~6%,q@^jh  
Utility.sleep(500); Qb!!J4|!  
breakWhile = true; z'?7]C2b  
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for(int i=0;i<nStartPos.length;i++) -T
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{ hsTFAfa'  
if(!fileSplitterFetch.bDownOver) ?(5o@Xq  
{ v%
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breakWhile = false; qhV,u;\.  
break; x[vpoB+c  
} 6WA|'|}=  
} ki;!WhF~  
if(breakWhile) 4*0:bhhhf_  
break; H!unIy|  
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//count++; ZB~l2  
//if(count>4) rnnX|}J  
// siteStop(); =dgo!k  
} Q^$ghZ6V  
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System.err.println("文件下载结束！"); 7))y}N:p
 
} Q=d.y&4%  
catch(Exception e){e.printStackTrace ();}
EX[B/YH  
} 4=u+ozCG  
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//获得文件长度 +<S9E'gT3V  
public long getFileSize() Wc~3^;
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{ &?SX4c~?u  
int nFileLength = -1; W3D
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try{ M:R8<.{  
URL url = new URL(siteInfoBean.getSSiteURL()); AI&qU/}  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); \bU`  
httpConnection.setRequestProperty("User-Agent","NetFox"); Qo'yS"g<9)  
8 ne/=N|,  
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int responseCode=httpConnection.getResponseCode(); >F/XZ
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if(responseCode>=400) f"vk# 3  
{ v2Dt3$@H6  
processErrorCode(responseCode); uzHT.
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return -2; //-2 represent access is error YSqv86  
} *,"jF!C&[  
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String sHeader; j'3j}G%\T  
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for(int i=1;;i++) *R5`.j =  
{ t
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//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); A[RHw<  
//Utility.log(in.readLine()); GHv{   
sHeader=httpConnection.getHeaderFieldKey(i); Vd,' s  
if(sHeader!=null) 2Oyy`k  
{ @'*eC}\E  
if(sHeader.equals("Content-Length")) 'z)hG#{I  
{ LyGUvi  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); yC W*fIaq  
break; wz|DT3"Xs  
} z(+&w
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} T_eJ}(p  
else VLiIO"u;  
break; zm3-C%:Bw  
} /$;,F't#2M  
} #S%4?  
catch(IOException e){e.printStackTrace ();} &B}Lo  
catch(Exception e){e.printStackTrace ();} >L^xlm%7o  
|
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Utility.log(nFileLength); O]t\B*%}  
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return nFileLength; q%>7L<r  
} qB:AkMd&  
/?Vdqci  
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//保存下载信息（文件指针位置） cg,Ua!c  
private void write_nPos()  @@Q6TB  
{ [q1Unm  
try{ }g>kpa0c  
output = new DataOutputStream(new FileOutputStream(tmpFile)); D z@1rc<B  
output.writeInt(nStartPos.length); \SOeTn+  
for(int i=0;i<nStartPos.length;i++) S`=n&'  
{ hd5$yU5JQ  
// output.writeLong(nPos); IhE9snJ[  
output.writeLong(fileSplitterFetch.nStartPos); (VyA6a8  
output.writeLong(fileSplitterFetch.nEndPos); T'.[F  
} rIVvO  
output.close(); JT04vm4  
} 3E,DipHg  
catch(IOException e){e.printStackTrace ();} FqwIJ|ct  
catch(Exception e){e.printStackTrace ();} \ZMP_UU(  
} Z ] 
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s O=4IBE  
//读取保存的下载信息（文件指针位置） HMV)U
{  
private void read_nPos() 4@6<  
{ W .U+.hR  
try{ T^]7R4Fg  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); /YFa ;2 W  
int nCount = input.readInt(); Q/py qe G  
nStartPos = new long[nCount]; it)ZP H  
nEndPos = new long[nCount]; \]8VwsP  
for(int i=0;i<nStartPos.length;i++) }~F~hf>s  
{ ^LVk5l)\>g  
nStartPos = input.readLong(); Umz05*  
nEndPos = input.readLong(); y@3Q;~l,  
} ePEe?o4;  
input.close(); :m Kxa  
} paWxanSt  
catch(IOException e){e.printStackTrace ();} TGf;_)El  
catch(Exception e){e.printStackTrace ();} XFQNr`  
} T#@{G,N  
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private void processErrorCode(int nErrorCode) b/u8} J  
{ Ns<?b;aK  
System.err.println("Error Code : " + nErrorCode); q jz3<`7-  
} zb:kanb-  
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//停止文件下载 g
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public void siteStop() O9^T3~x[V  
{ "Zcu[2,  
bStop = true; HTk\723Rdw  
for(int i=0;i<nStartPos.length;i++) >3PMnI  
fileSplitterFetch.splitterStop(); 
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} >b48>@~b
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} SE)nD@:  
//负责部分文件的抓取 ,q#2:b<E  
**FileSplitterFetch.java l^W uS|G[  
*/ ^=+e?F`:
{  
package NetFox; YJ,*(A18  
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import java.io.*; GoIQ>n
 
import java.net.*; O~PChUU*Y  
. I==-|  
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public class FileSplitterFetch extends Thread { f*m[|0qI<X  
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String sURL; //File URL ar$*a>'?  
long nStartPos; //File Snippet Start Position _ym"m,,7?  
long nEndPos; //File Snippet End Position zkexei4^<  
int nThreadID; //Thread's ID !E0!-UpY  
boolean bDownOver = false; //Downing is over ag8`O&+  
boolean bStop = false; //Stop identical aSL6zye ,  
FileAccessI fileAccessI = null; //File Access interface $UvPo0{  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException YQd:M%$  
{ OlY$v@|  
this.sURL = sURL; CU$#0f>  
this.nStartPos = nStart; exZLj0kvF  
this.nEndPos = nEnd; LZ<[ll#C  
nThreadID = id; BzN@gQo  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 |^( M{  
} rN5tI.iC  
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public void run() 7-*=|gl+  
{ +,5-qm)Gh>  
while(nStartPos < nEndPos && !bStop) % frfSGf.#  
{ HBiBv-=,  
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try{ VkZ.6kV  
URL url = new URL(sURL); 5 1dSFr<#  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); `1+F,&e  
httpConnection.setRequestProperty("User-Agent","NetFox"); 0L#/lDNk  
String sProperty = "bytes="+nStartPos+"-";
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httpConnection.setRequestProperty("RANGE",sProperty); lH2wG2  
Utility.log(sProperty); x({C(Q'O  
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80;n|nNB  
InputStream input = httpConnection.getInputStream(); u0 y 1  
//logResponseHead(httpConnection); 2@khSWV  
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byte[] b = new byte[1024]; )9L/sKz  
int nRead; 2k5/SV X  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Kq)MTlP0g  
{ I#G0, &Gv  
nStartPos += fileAccessI.write(b,0,nRead); j0mM>X HB  
//if(nThreadID == 1) 27A!\pn  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); "G?Yrh  
} d 6t:hn  
}dYBces  
2+Rv{%  
Utility.log("Thread " + nThreadID + " is over!"); }}r> K}  
bDownOver = true; FN^FvQ  
//nPos = fileAccessI.write (b,0,nRead); ~*.-  
} 9Q.#\  
catch(Exception e){e.printStackTrace ();} 'V&Y[7Aeq  
} 09h.1/  
} _[h8P9YI4  
~Z)/RT/  
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//打印回应的头信息 w$fJ4+  
public void logResponseHead(HttpURLConnection con) !3qVB  
{
=#xK=pRy;  
for(int i=1;;i++) e0HfP v_  
{ F0lOlS   
String header=con.getHeaderFieldKey(i); HM9fjl[  
if(header!=null) ej(ikj~j  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); <AoXEuD  
Utility.log(header+" : "+con.getHeaderField(header));
@n+=vC.xO  
else
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break; v]VWDT `  
} +.yT/y"  
} jZ*WN|FK?  
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public void splitterStop() \jU|(DE  
{ $XnPwOj  
bStop = true; >
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} tJ0NPI56yP  
r 2:2,5_  
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} aSutM  
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/* j2 %^qL  
**FileAccess.java a;AzY'R  
*//文件访问(定位，写) Dt|)=a  
package NetFox; EHf\L  
import java.io.*; `'S0*kMT  
9 ;i\g=  
vX|UgK?2^  
public class FileAccessI implements Serializable{ w3T]H_V  
9&]M**X  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 \wvg,j=  
RandomAccessFile oSavedFile; +-?/e-z")  
long nPos; yYZxLJ='  
x.mrCJn)  
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public FileAccessI() throws IOException w n|]{Ww35  
{ 1GCzy
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this("",0); 1fU,5+PH  
} dtt~ Bd  
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public FileAccessI(String sName,long nPos) throws IOException :mcYZPX#  
{ zbkMFD.{y  
oSavedFile = new RandomAccessFile(sName,"rw"); )?! [}t  
this.nPos = nPos; C~% 1w%nn  
oSavedFile.seek(nPos); s#9Ui#[=h  
} SGL|Ck  
[{u(C!7L`  
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public synchronized int write(byte[] b,int nStart,int nLen) 8hanzwoJ:  
{ V~IIYB7  
int n = -1; #dxgB:l)%l  
try{ J9~i%hzr  
oSavedFile.write(b,nStart,nLen); O[@q%&_  
n = nLen; pKG<Nvgz&  
} (5L-G{4  
catch(IOException e) +kK  
{ s@
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e.printStackTrace (); B=f,QU  
} ~Ou1WnmO  
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return n; #
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} !A3-0zN!  
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} aW_oD[l  
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hB;
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/* |KI UgI  
**SiteInfoBean.java 4bVO9aUG{  
*/ am1[9g8L  
package NetFox; x\e;+ubt}  
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public class SiteInfoBean { @D^^
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private String sSiteURL; //Site's URL oTjyN\?H  
private String sFilePath; //Saved File's Path 2NGeC0=  
private String sFileName; //Saved File's Name E_z;s3AXQ  
private int nSplitter; //Count of Splited Downloading File uQ$^;Pr  
:'L2J  
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public SiteInfoBean() e>rRTN  
{//nSplitter的缺省值为5 eYUr-rN+)z  
//default value of nSplitter is 5 uE/T2BX*  
this("","","",5); .0 )Y  
} Yj|eji7y  
f>o,N{|  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 9I7\D8r  
{ }GMbBZ:nKK  
sSiteURL= sURL; ^jB8Q  
sFilePath = sPath; RrZM&lXY  
sFileName = sName; +yob)%  
this.nSplitter = nSpiltter; IzOYduJ.  
wFh8?Z3u_  
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} 'nQVj  
7tM9u5FF  
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public String getSSiteURL() 1LJuCI=~  
{ gJiK+&8I  
return sSiteURL; -$VZtex  
} dCe4u<so\  
>>b3ZE|5  
,C.:;Ime({  
public void setSSiteURL(String value) D-Vai#Cd  
{ AE`We$!  
sSiteURL = value; X[s8X!#  
} =
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public String getSFilePath() qSqI7ptA\  
{ keW~ NM  
return sFilePath; up
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} -4rDbDsr  
kd:$oS_*s  
c3*t_!@oC  
public void setSFilePath(String value) SKuIF*"!S  
{
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sFilePath = value; _\PNr.D8  
} W!blAkM%i  
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public String getSFileName() 1(zsOeX  
{ FsB^CxVg  
return sFileName; ,t{,_uPJY  
} )3YtIH_  
4h!f/aF'  
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public void setSFileName(String value) t>GfM  
{ (bOpV>\Q7  
sFileName = value; Z@8vL  
} f'Iz G.R  
.x`M<L#M(  
\;-fi.Hrf$  
public int getNSplitter() XoLJL]+?  
{ [ xOzzp4  
return nSplitter; ;=j@, yu  
} I$NhXZ)KT  
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tt?58dm|  
public void setNSplitter(int nCount) =~Ynz7 /x  
{ )#a[-.OI  
nSplitter = nCount; JXG"M#{  
} &zQ2M#{82  
} <Llp\XcZ  
`b8v1Os^2  
+')f6P;t>=  
/* =cN&A_L(  
**Utility.java ]q-g[e'  
*/ L@75-T  
package NetFox; G$'jEa<:u  
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public class Utility { HkV1sT  
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public Utility() 8Y0"Cejq  
{ ~^
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} }R3=fbe,\  
nJRS.xs  
//线程睡眠 D'Z|}(d&  
public static void sleep(int nSecond) BQcE9~H  
{ ;U1UFqZ`  
try{ kyAXRwzI  
Thread.sleep(nSecond); O3N0YGhJ  
} I$Qs;- (  
catch(Exception e) @prG%vb"  
{ 4`Q3v4fOF  
e.printStackTrace (); ;fw1
 
} ky 8ep  
} BR'I+lQ  
,BFE=:ZIK  
//日志 "fg](Cp[z  
public static void log(String sMsg)
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{ $M_x!f'{>  
System.err.println(sMsg); RH}A  
} =X?\MVWB  
=.y*_Ja  
HL/bS/KX  
public static void log(int sMsg) uE[(cko  
{ OmM=o*d  
System.err.println(sMsg); LG~S8u  
} JKer//ng4  
} !R*-R.%  
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bX.ja;;   
/* @i^~0A#q*  
**TestMethod.java p^(&qk?ut  
*/ Hk>79};  
package NetFox; v7%X@j]ji  
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public class TestMethod { $?,a
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public TestMethod() k3+e;[My+  
{ ///xx/weblogic60b2_win.exe >7!6nF3x,  
try{ )s1Ib4C  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); K:'q>D@  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); l5+gsEux]  
SiteFileFetch fileFetch = new SiteFileFetch(bean); izKfU?2]X@  
fileFetch.start(); |F.)zC5{  
} 7?B.0>$3>V  
catch(Exception e){e.printStackTrace ();} o!:8nXw  
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} J5h+s-'  
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jBaB@LO9G  
public static void main(String[] args) :'aAZegQY  
{ 3E f1bhi  
new TestMethod(); 0y&I/2  
} 8/z3=O&  
} SuZ&vqS  
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