http断点续传简单实现（java)

/* !$98U~L  
**SiteFileFetch.java N:|``n>  
*/ IWYQ67Yj   
package NetFox; k*_Gg  
import java.io.*; 'n h^
;  
import java.net.*; `NhG|g  
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public class SiteFileFetch extends Thread { QP~["%}T  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ~;?mD/0k  
long[] nStartPos; //开始位置 v[|-`e*  
long[] nEndPos; //结束位置 uWx<J3~q.  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 YXo?(T..  
long nFileLength; //文件长度 +8<$vzB  
boolean bFirst = true; //是否第一次取文件 #;99vwc  
boolean bStop = false; //停止标志 2lfEJw($  
File tmpFile; //文件下载的临时信息 g]j&F65D  
DataOutputStream output; //输出到文件的输出流 <e! TF@  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） >}wFePl  
public SiteFileFetch(SiteInfoBean bean) throws IOException 9O &]!ga  
{ p7AsNqEp  
siteInfoBean = bean; ]ovtH

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//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 9'(^Coq  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); j![1  
if(tmpFile.exists ()) ~5Fx[q  
{ %KF I~Qk  
bFirst = false; 'g<"@SS+  
read_nPos(); .hckZx /  
} n-K/dI  
else !>'A2V~F  
{ 8nZ_.  
nStartPos = new long[bean.getNSplitter()]; 3` IR ^  
nEndPos = new long[bean.getNSplitter()]; !hJ!ck]M  
} 6 JI8l`S  
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} ?Xpk"N7  
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public void run() DN%JT[7  
{ aAqM)T83  
//获得文件长度 V.8Vy1$  
//分割文件 gs+nJ+b  
//实例FileSplitterFetch c)Ng9p  
//启动FileSplitterFetch线程 4-HBXG9#/  
//等待子线程返回 j0"4X  
try{ ){mqo
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if(bFirst) >'#vC]@  
{ P#3J@aRC  
nFileLength = getFileSize(); kXdXyq  
if(nFileLength == -1) uo?R;fX26  
{ KCpq<A%  
System.err.println("File Length is not known!"); qsEFf(9G  
} k]AL\) &W  
else if(nFileLength == -2) Zk~Pq%
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{ {oAD;m`  
System.err.println("File is not access!"); % dtn*NU  
} 3rMi:*?  
else 7[ n
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{ g?iZ RM  
for(int i=0;i<nStartPos.length;i++) 2f{p$YIt  
{ ]w,
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); vH}Vi
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} 7}NvO"u  
for(int i=0;i<nEndPos.length-1;i++) S@[NKY  
{ 8B+C[Q:+'  
nEndPos = nStartPos[i+1]; IR3+BDE)>  
} N`d%4)|{  
nEndPos[nEndPos.length-1] = nFileLength; _s<BXj  
} 'A3*[e|OS  
} ]N\D^`iQ  
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//启动子线程 D'%M#S0  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; -`\n/"#X6i  
for(int i=0;i<nStartPos.length;i++) Wm}T=L`  
{ s(Wys^[g  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), -|u yJh  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), nm_ta
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nStartPos,nEndPos,i); YHY*dk*|C  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); yzl}!& E  
fileSplitterFetch.start(); )b%zYD9p  
} QxbG-B^)=  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), x8c>2w;6x^  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); PYNY1|3  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", vo:h"ti  
nEndPos = " + nFileLength); *6][[)(  
// fileSplitterFetch[nPos.length-1].start(); <Vt"%C  
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//等待子线程结束 X]2x0  
//int count = 0; ,*9gy$  
//是否结束while循环 zgGJ<=G.  
boolean breakWhile = false; YADXXQ"
 
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while(!bStop) ml)\RL  
{ #N|JC d_  
write_nPos(); ,y-!h@(  
Utility.sleep(500); ' Qlj"U  
breakWhile = true; RH7!3ye  
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for(int i=0;i<nStartPos.length;i++) n
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{ a*&&6Fo  
if(!fileSplitterFetch.bDownOver) tC
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{ A"qDc  
breakWhile = false; Z<=L  
break; ugj I$u  
} 2[1t )EW  
} ] X)~D!mA  
if(breakWhile) u^Ktz DmL  
break; WAtv4  
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//count++; S !lrnH  
//if(count>4) 0ap'6  
// siteStop(); 1fM`n5?"  
} M+j*5wNy  
8N |K
  
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System.err.println("文件下载结束！"); FI$ -."F  
} B\aVE|~PB  
catch(Exception e){e.printStackTrace ();} P;K3T![  
} ={]POL\ A  
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//获得文件长度 q<^MC/]  
public long getFileSize() 7hLh}  
{ g HxR
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int nFileLength = -1; E{^W-  
try{ a3A3mB
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URL url = new URL(siteInfoBean.getSSiteURL()); e7-IqQA{3C  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); tv~Y5e&8  
httpConnection.setRequestProperty("User-Agent","NetFox"); oxUBlye  
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int responseCode=httpConnection.getResponseCode(); f`}/^*D  
if(responseCode>=400) amX1idHo^  
{ 1D!MXYgm1b  
processErrorCode(responseCode); WjSu4  
return -2; //-2 represent access is error ?'H+u[1.  
} cf^i!X0  
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String sHeader; ^ rUq{  
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for(int i=1;;i++) eJ ^I+?h  
{ Ejf5M\o  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); LylCr{s7  
//Utility.log(in.readLine()); `|v/qk7 ^?  
sHeader=httpConnection.getHeaderFieldKey(i); z;/8R7L&  
if(sHeader!=null) D6fd(=t1Z  
{ 'qG-
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if(sHeader.equals("Content-Length")) ox\D04:M  
{ R>&8%%#  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); \L}7.fkb8  
break; l,3,$  
} R[*n3 wB  
} !g)rp`?  
else ,)TnIByM  
break; h qhX  
} 2 J3/Eu  
} i]4nYYS  
catch(IOException e){e.printStackTrace ();} ~J5B?@2hK  
catch(Exception e){e.printStackTrace ();} C(z'oi:f  
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Utility.log(nFileLength); .wlKl[lE2  
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return nFileLength; {gD`yoPrV  
} q"S,<I<f  
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9`"#OQPn1  
//保存下载信息（文件指针位置） F~7TE91C  
private void write_nPos() 5DkEJk7a  
{ AGO"),  
try{ V,8Z!.MG  
output = new DataOutputStream(new FileOutputStream(tmpFile)); :>_oOn[_  
output.writeInt(nStartPos.length); *DZ7,$LQ~D  
for(int i=0;i<nStartPos.length;i++) \}Iq-Je   
{ Y7I\<JG<  
// output.writeLong(nPos); 0V^I.S/q  
output.writeLong(fileSplitterFetch.nStartPos); t
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output.writeLong(fileSplitterFetch.nEndPos); CBpwtI>p  
} iE_[]Vgc  
output.close(); 
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} Di}M\!-[  
catch(IOException e){e.printStackTrace ();} =w"Kkj>%oh  
catch(Exception e){e.printStackTrace ();} Rh$+9w  
} 3)2{c  
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//读取保存的下载信息（文件指针位置） ;mG
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private void read_nPos() iC>%P&|-)|  
{ 7fSNF7/+  
try{ Of$R+n.  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); V\]j^$  
int nCount = input.readInt(); @t*D<B$  
nStartPos = new long[nCount]; ukc 7Z OQ  
nEndPos = new long[nCount]; &N+`O)$  
for(int i=0;i<nStartPos.length;i++) ~_F;>N~  
{ T(]*jaB  
nStartPos = input.readLong(); xdz 6[8d8  
nEndPos = input.readLong(); l%?4L/J)#  
}  ylS
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input.close(); guf*>qNr  
} Q 8;JvCz  
catch(IOException e){e.printStackTrace ();} Dfc% jWbA  
catch(Exception e){e.printStackTrace ();} 2+C:Em0yI  
} gX(Xj@=(&  
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private void processErrorCode(int nErrorCode) gN73)uJ0  
{ D`'Cnt/  
System.err.println("Error Code : " + nErrorCode); kUT^o  
} YU)%-V\  
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//停止文件下载 sX3qrRY  
public void siteStop() I3'UrKKO  
{ ZitmvcMk  
bStop = true; o`7 Z<HF  
for(int i=0;i<nStartPos.length;i++) ZH>i2|W<  
fileSplitterFetch.splitterStop(); T\=#y  
ct OCj$$u  
""|;5kJS4  
} njO~^Hl7  
} G!G:YVWXP  
//负责部分文件的抓取 :2/jI:L~  
**FileSplitterFetch.java ~Lg ;7i1L  
*/ EE`[J0 (  
package NetFox; uqa pj("  
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import java.io.*; iVf7;M8O  
import java.net.*; t.VVE:A^%  
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public class FileSplitterFetch extends Thread { /lPnf7  
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String sURL; //File URL #b:YY^{g_  
long nStartPos; //File Snippet Start Position gu~R4@3  
long nEndPos; //File Snippet End Position u2`j\ Vu  
int nThreadID; //Thread's ID x*=m'IM[  
boolean bDownOver = false; //Downing is over @uN+]e+3  
boolean bStop = false; //Stop identical >H5t,FfQL  
FileAccessI fileAccessI = null; //File Access interface %6Vb1?x  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException sDTw</@  
{ ) j&khHD  
this.sURL = sURL; `L[q`r7  
this.nStartPos = nStart; v^F00@2I  
this.nEndPos = nEnd; )R?uzX^qf  
nThreadID = id; 8O60pB;4  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 8bs'Ek{'o  
} kumo%TXB&  
*PB/I4>{  
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public void run() -1NR]#P'  
{ @g+v2(f2v  
while(nStartPos < nEndPos && !bStop) 0
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{ }~ N\A  
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try{ 5K682+^5  
URL url = new URL(sURL); @]8flb )T  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); :D;pDl  
httpConnection.setRequestProperty("User-Agent","NetFox"); q #7Nk)<.  
String sProperty = "bytes="+nStartPos+"-"; f\Hw Y)^>  
httpConnection.setRequestProperty("RANGE",sProperty); /0Qo(  
Utility.log(sProperty); *O@Zn  
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InputStream input = httpConnection.getInputStream(); Qp)?wny4  
//logResponseHead(httpConnection); |`Yn'Mj8rm  
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byte[] b = new byte[1024]; ggkz fg&  
int nRead; u^c/1
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while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) XeY[;}9  
{ {D|ST2:E  
nStartPos += fileAccessI.write(b,0,nRead); X&5N89  
//if(nThreadID == 1) Q=vo5)t   
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); br 3-.g  
} ycki0&n3  
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Utility.log("Thread " + nThreadID + " is over!"); @qjN>PH~  
bDownOver = true; bi+g=cS  
//nPos = fileAccessI.write (b,0,nRead); "rEfhzmyF  
} ;mz#$"(  
catch(Exception e){e.printStackTrace ();} x?u@ j7[  
} -)Vy)hD,  
} ZqpK}I  
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2J$vX(  
//打印回应的头信息 \w1',"l`  
public void logResponseHead(HttpURLConnection con) ?OoI63&  
{ Z)=S>06X Q  
for(int i=1;;i++) ePIN<F;
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{ ydY 7 :D  
String header=con.getHeaderFieldKey(i); $UK m[:7  
if(header!=null) ?$tD  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); tl7:L>  
Utility.log(header+" : "+con.getHeaderField(header)); 3XQe? 2:<  
else =ud~  
break; %hZX XpuO  
} UWS 91GN@  
} }lhk;#r  
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public void splitterStop() G,^ ?qbHg  
{ M.Tp)ig\#  
bStop = true; _5(p=Zc  
} "$K]+0ryG<  
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} 5M #',(X  
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/* hu"-dT;4]  
**FileAccess.java 0`p"7!r  
*//文件访问(定位，写) ot!m=s  
package NetFox; G?\eO&QG{"  
import java.io.*; Ex*{iJ;\  
{}iS5[H]  
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public class FileAccessI implements Serializable{ "iX\U'`  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 m?Cb^WgcF  
RandomAccessFile oSavedFile; Oj_F1. r  
long nPos; DrAIQ7Jd  
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public FileAccessI() throws IOException O\Z!7UQ$  
{ L>E{~yh  
this("",0); eLXL5&}`fh  
} oTXIs4+G  
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public FileAccessI(String sName,long nPos) throws IOException q*Hg-J}  
{ &?5)Jis:  
oSavedFile = new RandomAccessFile(sName,"rw"); B~qo^ppVU  
this.nPos = nPos; c'Ibgfx%
m  
oSavedFile.seek(nPos); H]wP\m)  
} T3SFG]H  
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public synchronized int write(byte[] b,int nStart,int nLen) (.YSs   
{ EL z5P}L6  
int n = -1; 7 H:y=?X6  
try{ F]>
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oSavedFile.write(b,nStart,nLen); v.TgB)  
n = nLen; -JPkC(V7]  
} c>3? T^=  
catch(IOException e) 5T(
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{ ycOnPTh  
e.printStackTrace (); 6biR5&Y5U&  
} $MNJsc^n  
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return n; cT/mi":8{  
}
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} \b!E"I_^  
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/* c9CFGo?)N  
**SiteInfoBean.java e00}YWf%  
*/ -J#RGB{7  
package NetFox; wxPl[)E  
\*b  .f  
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public class SiteInfoBean { ,2 W=/,5A  

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private String sSiteURL; //Site's URL 3k(tv U+eC  
private String sFilePath; //Saved File's Path S+wT}_BQ  
private String sFileName; //Saved File's Name ONy\/lu|  
private int nSplitter; //Count of Splited Downloading File "_dg$j`Y&&  
XIZN9/;  
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public SiteInfoBean() }YM\IPsPu  
{//nSplitter的缺省值为5 5VQ-D`kE+  
//default value of nSplitter is 5 [UC_  
this("","","",5); EEK!'[<,sE  
} G{>PYLxOb  

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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) I^u~r.  
{ [uHC AP  
sSiteURL= sURL; 9rT^rTV  
sFilePath = sPath; -{9mctt/gE  
sFileName = sName; ;bg]H >$U7  
this.nSplitter = nSpiltter; Sf.OBU1rs  
"Y^9g/  
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} ]o0]i<:  
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public String getSSiteURL() tu* uQ:Ipk  
{ T{m) = (q  
return sSiteURL; $0un`&W  
} S ~fz  
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public void setSSiteURL(String value) EStui>ho  
{ xDH#K0-#L  
sSiteURL = value; j3N d4#  
} N|>JLZ>  
.QZjJ9pvK  
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public String getSFilePath() 9%NobT  
{ IvY3iRq6  
return sFilePath; AJ
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} *V\.6,^v  
EU|IzUjFj|  
(S+/e5c)  
public void setSFilePath(String value) JR15y3F  
{ YwF&-~mp7n  
sFilePath = value; yZ)9Hd  
} 3#dz6+  
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public String getSFileName() cqJXZ.XC  
{ Aaq%'07ihW  
return sFileName; I=<Qpd4  
} i '*!c  
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public void setSFileName(String value) ){'<67dK  
{ /d:hW4}<}.  
sFileName = value; dW!El^w}  
} D|m3.si  
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public int getNSplitter() ry=8Oq&[~  
{ L*,
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return nSplitter; H&p:  
} Qox/abC h  
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public void setNSplitter(int nCount) 'v CMf  
{ & /T}  
nSplitter = nCount; m;>G]Sbe  
} <Lxp t  
} w{xa@Q]t-  
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/* N"G\
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**Utility.java r63l(  
*/ fpC":EX@r  
package NetFox; k+P3z&e  
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public class Utility { ,]:<l  
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public Utility() 4K7ved)  
{ g}R Cjl4  
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} KU oAxA  
>bQOpGy}l  
//线程睡眠 fjy\Q  
public static void sleep(int nSecond) ]u$tKC  
{ W'"?5} (  
try{ )uo".n|n~B  
Thread.sleep(nSecond); 3%GsTq2o  
} $|J+  
catch(Exception e) 7 L,`7k|  
{ 7#G!es  
e.printStackTrace (); Et(H6O8  
} j nSZ@u  
} H'/V<
%  
/j$pV  
//日志 @sZ7Ka  
public static void log(String sMsg) X@tA+  
{ I(7iD. ^:  
System.err.println(sMsg); YLA(hg|  
} 
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iV?8'^  
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public static void log(int sMsg) W5Pur lu?  
{ HpIi-Es7C  
System.err.println(sMsg); 9
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} 3gVU#T[[  
} +2 oZML  
cl&?'` )  
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/* G;u~H<  
**TestMethod.java MmvOyKNZF  
*/ $^^M&[b-  
package NetFox; ',WJ'g  
XP}5i!}}7=  
2YWO'PL  
public class TestMethod { qM26:kB{  
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.*oL@iX  
public TestMethod() 1D8S}=5&  
{ ///xx/weblogic60b2_win.exe CPcUB4a%#  
try{ %@)q=*=y  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); iM:-750n/  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); G:lhrT{  
SiteFileFetch fileFetch = new SiteFileFetch(bean); jCNR63/  
fileFetch.start(); Nb_Glf  
} mrG?5
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catch(Exception e){e.printStackTrace ();} w~crj$UM  
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} GIpYx`mHi  
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public static void main(String[] args) lV4TFt,  
{ 7SYe:^Dx  
new TestMethod(); d#bg(y\G|  
} %P<fz1  
} (,+#H]L  
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