http断点续传简单实现（java)

/* /6@iRswa  
**SiteFileFetch.java dnXre*rhz  
*/ b?Zt3#  
package NetFox; M,V~oc5
 
import java.io.*; 5S&'O4yz^  
import java.net.*; D Xjw"^x  
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public class SiteFileFetch extends Thread { We51s^(  
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SiteInfoBean siteInfoBean = null; //文件信息Bean :l/?cV
;  
long[] nStartPos; //开始位置 g(`m#&P>G  
long[] nEndPos; //结束位置 LLlt9(^d  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 }>T$2"pf  
long nFileLength; //文件长度 qY^@^)b[  
boolean bFirst = true; //是否第一次取文件 a"6AZT"8  
boolean bStop = false; //停止标志 riuG,$
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File tmpFile; //文件下载的临时信息 zJ9[),;7B  
DataOutputStream output; //输出到文件的输出流 :#I7);ol  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） F )|0U~  
public SiteFileFetch(SiteInfoBean bean) throws IOException P_{jZ}y(  
{ npD`9ff  
siteInfoBean = bean; ,KO_h{mI<  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); +&j&es  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); [h;&r"1  
if(tmpFile.exists ()) ML9nfB^z!  
{ 8:QnxrODP  
bFirst = false; m5w ZS>@  
read_nPos(); J#OiY  
} Jx
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else 1>wQ&{  
{ g~#HiBgWq[  
nStartPos = new long[bean.getNSplitter()]; ^P| K2at  
nEndPos = new long[bean.getNSplitter()]; 6%nKrK  
} (Z
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} /-_<RQ  
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public void run() Ny oRp  
{ F9Y/Z5 Ea  
//获得文件长度 h%0hryGB  
//分割文件 pl.D h  
//实例FileSplitterFetch
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//启动FileSplitterFetch线程 [LcHO] _^M  
//等待子线程返回 =%UX"K`  
try{ $&>z`bAS>  
if(bFirst) `_*NFv1_  
{ K@DK4{  
nFileLength = getFileSize(); gr%!<2w  
if(nFileLength == -1) 0 jszZ_  
{ \KpSYX1  
System.err.println("File Length is not known!"); luYa+E0  
} LBs:O*;  
else if(nFileLength == -2) afJ`1l  
{ rElbzL"&<  
System.err.println("File is not access!"); @mbR I0  
} NDt +m  
else NE'4atQ|  
{ B"9/+Yj  
for(int i=0;i<nStartPos.length;i++) Xgs 31#K  
{ K.{:H4_  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Z\@m_/g  
} 4Em$L]7  
for(int i=0;i<nEndPos.length-1;i++) 
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{ |i-d#x8  
nEndPos = nStartPos[i+1]; B > sTM  
} ?cF-w!>o8  
nEndPos[nEndPos.length-1] = nFileLength; |x[zzx# >-  
} nKP[U=ac  
} Ba]J3Yp,z  
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//启动子线程 /%'>?8/  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; oK!W<#  
for(int i=0;i<nStartPos.length;i++) zURob MpE#  
{ 6)QJms  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), |KM<\v(A{  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), p?q~.YY  
nStartPos,nEndPos,i); T{VdlgL  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); E(l'\q'.  
fileSplitterFetch.start(); ELlTR/NW  
} v;r!rZX  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 0i4X,oHjG  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); LZ"yMnhOf  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", W%)uKQha  
nEndPos = " + nFileLength); Lh"!Z  
// fileSplitterFetch[nPos.length-1].start(); N0:gY]o%  
?[|T"bE5[  
#t^y$9^  
//等待子线程结束 qq)Dh'5*e,  
//int count = 0; j|N8"8"  
//是否结束while循环 z g'1T2t  
boolean breakWhile = false; qBkI9H  
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while(!bStop) :YAxL J  
{ KG5h$eM'  
write_nPos(); kDrqV{_  
Utility.sleep(500); m^O9G?  
breakWhile = true; WrS|$: 0  
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for(int i=0;i<nStartPos.length;i++) JMnk~8O  
{ &vy/Vd  
if(!fileSplitterFetch.bDownOver) )Apg  
{ yLo{^4a.  
breakWhile = false; ##6_kcL:6G  
break; X)tf3M {J@  
} \U1fUrw$*  
} bg8<}~zg  
if(breakWhile) `?X=
@  
break; \;b)qB  
S @EkrC\4n  
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//count++; P[.BK  
//if(count>4) b0~AN#Es  
// siteStop(); ~m]sJpW<"  
} E27N1J+1  

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System.err.println("文件下载结束！"); ~"Pu6-\VT  
} `@Q%}J  
catch(Exception e){e.printStackTrace ();} ~BNLzt3%O  
} w_gPX0N}3n  
!_EaF`oh(  
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//获得文件长度 3E!#?N|v  
public long getFileSize() 6Q&*V7EO  
{ y5XHJUTu  
int nFileLength = -1; =-ky%3:`@  
try{ y11/:|  
URL url = new URL(siteInfoBean.getSSiteURL()); 9Yh0' <Z  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); cR0RJ$[d  
httpConnection.setRequestProperty("User-Agent","NetFox"); 
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int responseCode=httpConnection.getResponseCode(); WhO;4-q)2  
if(responseCode>=400) yAu-BObD  
{ FyZa1%Tv@  
processErrorCode(responseCode);
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return -2; //-2 represent access is error reyN5n~4U  
} zS@"ITy  
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String sHeader; >bf29tr  
c !$ 8>  
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for(int i=1;;i++) hSgfp  
{ v;E7UL .w  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); )C @W_cfMN  
//Utility.log(in.readLine()); }),tk?\  
sHeader=httpConnection.getHeaderFieldKey(i); G;n'c7BV  
if(sHeader!=null) <&7KcvBn"4  
{ TK)Kq  
if(sHeader.equals("Content-Length")) N0@&eX|$i4  
{
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nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); >H@ zP8  
break; %!r>]M <  
} #?xhfSgr  
} dQ=mg#(  
else hcw
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break; KzQ\A!qG  
} f6 zT  
} 6]i"lq
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catch(IOException e){e.printStackTrace ();} Dt~Jx\\  
catch(Exception e){e.printStackTrace ();} gI&& LwT4  
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Utility.log(nFileLength); apxZ}  
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return nFileLength; 8oSndfV  
} $XFiH~GI  
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qll)  
//保存下载信息（文件指针位置） ,3G8
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private void write_nPos() [)}F4Jsz%  
{ `;7
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try{ u,:GJU  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ,}!OJyT  
output.writeInt(nStartPos.length); 8>Xyz`$kH  
for(int i=0;i<nStartPos.length;i++) ~jab/cR  
{ D
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// output.writeLong(nPos); SxMrX C*  
output.writeLong(fileSplitterFetch.nStartPos); K2T&U$,  
output.writeLong(fileSplitterFetch.nEndPos); t[B\'f!  
} 5oQy $Y  
output.close(); pYo]lO  
} $_-f}E  
catch(IOException e){e.printStackTrace ();} ]8(_{@/  
catch(Exception e){e.printStackTrace ();} *r
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} UV%Al)3  
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;d1\2H  
//读取保存的下载信息（文件指针位置） n'D1s:W^B  
private void read_nPos() 7|6uY  
{ !>B|z=  
try{ 1F*gPhm  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); }&d@6m]  
int nCount = input.readInt(); xrX^";}j  
nStartPos = new long[nCount]; R07K
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nEndPos = new long[nCount]; w/r wE  
for(int i=0;i<nStartPos.length;i++) \
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{ :E/]Bjq$;  
nStartPos = input.readLong(); ^[}^+  
nEndPos = input.readLong(); 3^l@!Qw  
} +K4d(!Sb  
input.close(); *%L:soM'Ll  
} Z 6^AO=3  
catch(IOException e){e.printStackTrace ();} =[!&&,c=  
catch(Exception e){e.printStackTrace ();} \2#>@6Sqrl  
} TI-8I)  
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private void processErrorCode(int nErrorCode) zhH-lMNj-  
{ 1u&}Lq(  
System.err.println("Error Code : " + nErrorCode); w66iLQ\@  
} >3V{I'^^-  
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//停止文件下载 [z$th  
public void siteStop() OD!b*Iy|  
{ 2xvTijO0  
bStop = true; !|{
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for(int i=0;i<nStartPos.length;i++) q"OvuHBSOn  
fileSplitterFetch.splitterStop(); [psW+3{bG  
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} c%_I|h<?iT  
} UD`bK a`E  
//负责部分文件的抓取 RiC1lCE  
**FileSplitterFetch.java g+o
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*/ 4S>A}rWz  
package NetFox; _p/ _t76s  
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import java.io.*; h.@
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import java.net.*; Q?KWiF
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public class FileSplitterFetch extends Thread { >%k:++b{  
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String sURL; //File URL -@{5 u d  
long nStartPos; //File Snippet Start Position !E<y:$eH:  
long nEndPos; //File Snippet End Position UU')V  
int nThreadID; //Thread's ID 5J
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boolean bDownOver = false; //Downing is over To1 .U)do  
boolean bStop = false; //Stop identical hnag<=  
FileAccessI fileAccessI = null; //File Access interface LIYj__4=|  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException XVcY?_AS#  
{ (LzVWz m  
this.sURL = sURL; 4{JoeIRyz  
this.nStartPos = nStart; Tg|0!0qD]F  
this.nEndPos = nEnd; zKB$n.H  
nThreadID = id; Jhdo#}Ub  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 R7u&`  
} $d2mcwh\  
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public void run() @&(0]kZ6  
{ EYNi`  
while(nStartPos < nEndPos && !bStop) rnW(<t"  
{ r
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+~b@W{  
try{ qScc~i Oq  
URL url = new URL(sURL); 9<BC6M_/  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); I;xrw?=\L  
httpConnection.setRequestProperty("User-Agent","NetFox"); c\cPmj@  
String sProperty = "bytes="+nStartPos+"-"; o NX-vN-  
httpConnection.setRequestProperty("RANGE",sProperty); 2fIHFo\8  
Utility.log(sProperty); ~R-P%l P  
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InputStream input = httpConnection.getInputStream(); ayR=GqZ1  
//logResponseHead(httpConnection); Q!7il<S  
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+?r,
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byte[] b = new byte[1024]; PhTMXv<cE  
int nRead; J?VMQTa/+  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 5Fa.X|R~  
{ Fq\vFt|m<  
nStartPos += fileAccessI.write(b,0,nRead); S"+X+Oxp7?  
//if(nThreadID == 1) jroR2*  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 2wR?ON=Q  
} bzYj`t?  
4#?Sxs  
3%gn:.9N  
Utility.log("Thread " + nThreadID + " is over!"); ]\DZW4?
'  
bDownOver = true; 4mYJi#e6x  
//nPos = fileAccessI.write (b,0,nRead); !R@v\Eu  
} (55k70>i3  
catch(Exception e){e.printStackTrace ();} WbF[4x  
} 6! `^}4  
} #Bu W  
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//打印回应的头信息 o@T-kAEf-.  
public void logResponseHead(HttpURLConnection con) b]A9$-  
{ WBc,/lgZ  
for(int i=1;;i++) ux>wa+XFa  
{ ->"Z1  
String header=con.getHeaderFieldKey(i); O^/z7,  
if(header!=null) %DOV)Qc2  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 3vdhoS|  
Utility.log(header+" : "+con.getHeaderField(header)); B?M&j  
else +%E)]*Ym  
break; Q8d-yJs&  
} '0ks`a4q  
} hbfN1"z  
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public void splitterStop() +UvT;"  
{ /:S&1'=  
bStop = true; 3` ,u^ w  
} AN)exU ?  
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{N.JA=  
} \3K%>   
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/* Xg<R+o  
**FileAccess.java 7bk=D~/nSg  
*//文件访问(定位，写) N$&)gI:  
package NetFox; T( LlNq  
import java.io.*; u7>{#]  
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public class FileAccessI implements Serializable{ o57r ,`N  
pDYcsC{p  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 rf\/Y"D  
RandomAccessFile oSavedFile; Kg8n3pLAX  
long nPos; d@b" ~r}  
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public FileAccessI() throws IOException :<QmG3F  
{ a8w/#!^34  
this("",0); "A9qC*6[  
} Pl/}`H:R&  
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public FileAccessI(String sName,long nPos) throws IOException W]B75  
{ =PM6:3aKh  
oSavedFile = new RandomAccessFile(sName,"rw"); [\BLb8  
this.nPos = nPos; 'lWgHmE  
oSavedFile.seek(nPos); #ULjK*)R  
} $R&K-;D/8  
v?O6|0#x  
GS)4,.  
public synchronized int write(byte[] b,int nStart,int nLen) c9/&A  
{ %96l(JlJ)B  
int n = -1; HI\V29 a  
try{ Fo.p}j+>  
oSavedFile.write(b,nStart,nLen); 'nQQqx%v  
n = nLen; lnQfpa8j  
} l$:?82{  
catch(IOException e) qmy3pnL  
{ 4Pv Pp{Y  
e.printStackTrace (); gcI?)F   
} /:GeXDJw  
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return n; 0wE)1w<C~  
} O'.sK pXe  
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} 8M6wc394  
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/* uXuA4o$t-  
**SiteInfoBean.java N~! GAaD  
*/ sZh| <2  
package NetFox; /cC4K\M  
ozUsp[W>  
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public class SiteInfoBean { \N
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private String sSiteURL; //Site's URL LXq0hI  
private String sFilePath; //Saved File's Path S4C4_*~Vd  
private String sFileName; //Saved File's Name njGZ#{"eC  
private int nSplitter; //Count of Splited Downloading File \J-}Dp\0b  
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Y+Cqc.JBQ  
public SiteInfoBean() WT'?L{  
{//nSplitter的缺省值为5 j`l'Mg  
//default value of nSplitter is 5 @3_."-
d  
this("","","",5); ;y]BXW&l&  
} =2OLyZDI  
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#!7b3>}  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Aq,&p,m03  
{ I~T~!^}U  
sSiteURL= sURL; j}aU*p~N  
sFilePath = sPath; &:[hUn8jU  
sFileName = sName; Wu@v%!0  
this.nSplitter = nSpiltter; #v\o@ArX  
X*< !_3  
i-M<_62c  
} (_nU}<y_i  
&pFP=|Pq  
/D,<2>o  
public String getSSiteURL() Z"N}f ,  
{ jn._4TQ*}  
return sSiteURL; d Z
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} `%$l b:e  
8Y P7'Fz  
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public void setSSiteURL(String value) !n`
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{ >o4Ih^VB  
sSiteURL = value; n_eN|m?@  
} ftRzgW);  
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public String getSFilePath() XGSgx  
{ WKB K)=  
return sFilePath; 2@>#?c7  
} get$r5  
)~C+nb '6/  
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public void setSFilePath(String value) -`ss7j&b3  
{ 19*
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sFilePath = value; LNOz.2fr>  
} -:|t^RM;FT  
I`uOsZBO/  
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public String getSFileName() 4=C7V,a  
{ !~-@p?kW/  
return sFileName; 4%>2>5  
} DgGG*OXY  
EeDK ^W8N  
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public void setSFileName(String value) _Eus7  
{ UUR` m  
sFileName = value; +qee8
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} 5K {{o''  
{(_>A\zi  

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public int getNSplitter() @%gth@8  
{ k[8{N  
return nSplitter; C7_nA:Rc  
} |`Q2K9'4bL  
O>/&-Wk=  
~pPj  
public void setNSplitter(int nCount) Y~P* !g  
{ [_1K1i"m  
nSplitter = nCount; li  
} fT0+inRG  
} cjc1iciZ  
>{.|Ng4K  
mu@IcIb>  
/* AR6hfdDDT  
**Utility.java J9q[u[QZ9O  
*/ n7iIY4gZ  
package NetFox; { v#wU  
^$~&e :{  
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public class Utility { r(p@{L185  
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UY/qI%#L#,  
public Utility() _&K>fy3t&  
{ !H4C5wDu  
!f)^z9QX8  
wG",Obja  
} f_;6uCCO  
&m{vLw  
//线程睡眠 ?xYoCn}Z  
public static void sleep(int nSecond) WNo<0|X  
{ 3\H0Nkubts  
try{ OHK]=DH:M  
Thread.sleep(nSecond); Ry"N_Fb  
} 6&[rATU+  
catch(Exception e) 7Lx=VX#]q  
{ lzK,VZ=mM  
e.printStackTrace (); C>Cb  
} :za:gs0  
} W,|JocDq  
e)2w&2i`(F  
//日志 -b'a-?  
public static void log(String sMsg) B;^YHWJ6i  
{ d/l>~%bR  
System.err.println(sMsg); D:fLQ8a  
} ebIRXUF}>  
C
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public static void log(int sMsg) ]C5/-J,F  
{ 2M*84oh8P  
System.err.println(sMsg); 7"s8G7  
} lJdwbuB6  
} xF7q9'/F  
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>f-*D25f%  
/* 7|^5E*8/  
**TestMethod.java A)641"[  
*/ t+2,;G  
package NetFox; 1LonYAHF  
iU"{8K,  
%-#rzeaW  
public class TestMethod { f]DO2r  
TUM7(-,9  
ZGC*BP/  
public TestMethod() >NAg*1  
{ ///xx/weblogic60b2_win.exe /4Jm]"  
try{ f~v@;/HL  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); nW!pOTJq21  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); &ngG_y8}&  
SiteFileFetch fileFetch = new SiteFileFetch(bean); M}qrF~   
fileFetch.start(); d D;r35h=  
} :y3e-lr  
catch(Exception e){e.printStackTrace ();} ILMXWw  
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} )=6o,  
#({ 9M  
$pfN0/`(  
public static void main(String[] args) Z{rD4S@^  
{ ,Ep41v;T%`  
new TestMethod(); 8 CCA}lOG  
} v)-:0f  
} y4`uU1=  
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