http断点续传简单实现（java)

/* 3-&~jm~"  
**SiteFileFetch.java uq;yR[w"  
*/ RL$%Vy0  
package NetFox; &Q#*Nnb3  
import java.io.*; g/_0WW]}  
import java.net.*; )E}@h%d  
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public class SiteFileFetch extends Thread {  "iR:KW@  

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SiteInfoBean siteInfoBean = null; //文件信息Bean ^`B;SSV  
long[] nStartPos; //开始位置 l4dG=x}M]  
long[] nEndPos; //结束位置 %`QgG   
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Q6wa-Y,  
long nFileLength; //文件长度 zvVo-{6  
boolean bFirst = true; //是否第一次取文件 bkc*it  
boolean bStop = false; //停止标志 "}wO<O6[  
File tmpFile; //文件下载的临时信息 vK[%cA"  
DataOutputStream output; //输出到文件的输出流 KyyVO"  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） .xuzu#-  
public SiteFileFetch(SiteInfoBean bean) throws IOException !\$V?*p7  
{ 9K#3JyW*  
siteInfoBean = bean; 7BL)FJ]UR]  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); jCXBp>9$M  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); &q@brX<,=  
if(tmpFile.exists ()) #
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{ EZN!3y|m  
bFirst = false; g8l6bh$}  
read_nPos(); yCA8/)>Gm  
} ma+AFCi  
else ~\AF\n%  
{ 0#DE
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nStartPos = new long[bean.getNSplitter()]; :o .+<_&  
nEndPos = new long[bean.getNSplitter()]; =JW-EQ6[T  
} co3\1[q"b  
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}
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public void run() f*B
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{ yW(|auq  
//获得文件长度 S<-nlBs.  
//分割文件 KbtV>  
//实例FileSplitterFetch dzBP<Xyh  
//启动FileSplitterFetch线程 &b`W<PAc?4  
//等待子线程返回 (wM` LE(Ks  
try{ D[#V  
if(bFirst) jeJgDAUv  
{ DJ@n$G`^^  
nFileLength = getFileSize(); (S?Y3l|  
if(nFileLength == -1) 9O:l0 l  
{ #XA`n@2Uoo  
System.err.println("File Length is not known!"); B~N3k  
} Qj;{Z*l%+  
else if(nFileLength == -2) Z#L4n#TT  
{ BkGExz  
System.err.println("File is not access!"); [5& nH@og  
} #MlpOk*G  
else Y}v3
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{ ~^V&n`*7D  
for(int i=0;i<nStartPos.length;i++) Pv/v=s>X  
{ XWnP(C9?  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); bY=[ USgps  
} C[G+SA1&W  
for(int i=0;i<nEndPos.length-1;i++) |Rz.Pt6  
{ @anjjC5a~  
nEndPos = nStartPos[i+1]; O"+0 b|  
} m;]wKd"  
nEndPos[nEndPos.length-1] = nFileLength; M@{#yEP  
} P|bow+4  
} U
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//启动子线程 jt on\9  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ;//9,x9;t  
for(int i=0;i<nStartPos.length;i++) HyU:BW;  
{ rO$pj~!|Q  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), =I546($  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 5EcVW|(  
nStartPos,nEndPos,i); UGI<
V!  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 7!pKlmQ  
fileSplitterFetch.start(); ZQ_6I}i")  
} $VvgzjrH  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 'v~'NWfd  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); PnA{@n\  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", !T][c~l  
nEndPos = " + nFileLength); `.@sux!lu  
// fileSplitterFetch[nPos.length-1].start(); YE{ [f@i0  
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//等待子线程结束 #~|k EGt  
//int count = 0; P,{Q k~iu  
//是否结束while循环 p@su:B2Rl  
boolean breakWhile = false; W&*&O,c  
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while(!bStop) :xPo*#[Z(A  
{ "mW'tm1+  
write_nPos(); gCb+hQq\  
Utility.sleep(500); >8"Svt$  
breakWhile = true; **Ioy+  
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for(int i=0;i<nStartPos.length;i++) {fzX2qMZ]  
{ bGH#s {'5  
if(!fileSplitterFetch.bDownOver) gmRc4o  
{ OL
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breakWhile = false; *x|%Nua"  
break; FnA Kfh(  
} 1+;bd'Ie  
} }}=n]_f  
if(breakWhile) E]OexRJ^i  
break; sv%X8  
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//count++; Nh.+woFq4  
//if(count>4) {Ya$Q#l  
// siteStop(); *#mmk1`  
} RW. qw4  
2{rWAPHgz  
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System.err.println("文件下载结束！"); vPNbV  
} @-!P1]V|  
catch(Exception e){e.printStackTrace ();} ;\mX=S|a  
} $v;WmYTJ  
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//获得文件长度 X3:z=X&Zd  
public long getFileSize() ZL6HD n!  
{ 3\XNOJH  
int nFileLength = -1; Svn7.Ivep  
try{ )/$J$'mcxd  
URL url = new URL(siteInfoBean.getSSiteURL()); c,~uurVi  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); bkV<ZUW|;  
httpConnection.setRequestProperty("User-Agent","NetFox"); >zW2w2O3  
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int responseCode=httpConnection.getResponseCode(); M%S7cIX ]F  
if(responseCode>=400) 6VGY4j}:(  
{ SsZC g#i  
processErrorCode(responseCode); ?Ij
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return -2; //-2 represent access is error T7,]^ 1  
} `MOw\Z)..  
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String sHeader; >&PM'k  
; j!dbT~5  
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for(int i=1;;i++) ka9@7IFM  
{ gZ,h95
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//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); odhS0+d^  
//Utility.log(in.readLine()); g-sNYd%?a  
sHeader=httpConnection.getHeaderFieldKey(i); = j1Jl^[  
if(sHeader!=null) >a?Bk4w  
{ e'3V4iU]  
if(sHeader.equals("Content-Length")) X,k^p[Rcu  
{ O+}py{ st  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); N#T'}>ty  
break; V+E8{|dYL  
} #DUfEZ  
} eP-|3$  
else 9&Jf4lC94  
break; `}Zqmfs  
} xS,24{-HJ  
} 'Lrn<  
catch(IOException e){e.printStackTrace ();} BPO5=]W 7  
catch(Exception e){e.printStackTrace ();} X0;u7g2Yz  
}(nT(9|  
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Utility.log(nFileLength); fN&\8SPE  
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return nFileLength; r].n=455[  
} ~7PD/dre  
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//保存下载信息（文件指针位置） fqgp{(`@>  
private void write_nPos() DSU8jnrL  
{ vE:*{G;Y  
try{ k
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output = new DataOutputStream(new FileOutputStream(tmpFile)); 2RkW/)A9  
output.writeInt(nStartPos.length);
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for(int i=0;i<nStartPos.length;i++) >w S'z]T9  
{ k>($[;k|b  
// output.writeLong(nPos); Ehx9-*]
 
output.writeLong(fileSplitterFetch.nStartPos); <fUo@]Lv   
output.writeLong(fileSplitterFetch.nEndPos); S^rf^%  
} Cyg2o<O@  
output.close(); )E^S+ps  
} V`I4"}M1  
catch(IOException e){e.printStackTrace ();} \d@5*q  
catch(Exception e){e.printStackTrace ();} BHY8G06  
} l0Q5q)U1A  
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) D@j6r  
//读取保存的下载信息（文件指针位置） +{:uPY#1  
private void read_nPos() }DhqzKl  
{ ok:uTeJI  
try{ S1QMS  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 2aYBcPFQh#  
int nCount = input.readInt(); Scrj%h%[  
nStartPos = new long[nCount]; xo[o^go  
nEndPos = new long[nCount]; E 2nz  
for(int i=0;i<nStartPos.length;i++) Q~,Mzt"}W  
{ P<PZ4hNx  
nStartPos = input.readLong(); igxO:]
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nEndPos = input.readLong(); t8^1wA@@V  
} (4YLUN&1O$  
input.close(); -<#) ]um  
} NM3;l}Y8  
catch(IOException e){e.printStackTrace ();} 5XKTb  
catch(Exception e){e.printStackTrace ();} S{=5nR9j  
} jK w 96  
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private void processErrorCode(int nErrorCode) MAek856  
{ X1@DI_  
System.err.println("Error Code : " + nErrorCode); |}=eY?iXo  
} j?K$w`  
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//停止文件下载 U{2xgNJ  
public void siteStop() #V>R#Oh}  
{ P 9?cp{
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bStop = true; y[_k/.1  
for(int i=0;i<nStartPos.length;i++) _uIS[%4g  
fileSplitterFetch.splitterStop(); FZi@h  
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} K\K& K~Z  
} cN,*QN  
//负责部分文件的抓取 U=n7RPw  
**FileSplitterFetch.java <,} h8;Fr  
*/ V^_
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package NetFox; {-Y;!  
:iE b^F}  
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import java.io.*; 94tfR$W;-  
import java.net.*; kdNo<x1o  
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public class FileSplitterFetch extends Thread { y'2|E+*V  
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String sURL; //File URL YSD G!  
long nStartPos; //File Snippet Start Position s$M(-"mg  
long nEndPos; //File Snippet End Position dNe!X0[  
int nThreadID; //Thread's ID iWCYK7c@.-  
boolean bDownOver = false; //Downing is over )?rq8VO  
boolean bStop = false; //Stop identical a4*v'Xc5  
FileAccessI fileAccessI = null; //File Access interface tguB@,O  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException eRMN=qP.q  
{ EX]+
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this.sURL = sURL; a'VQegP(f\  
this.nStartPos = nStart; J M`w6}  
this.nEndPos = nEnd; [q9B"@X  
nThreadID = id; P $`1}  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ]1 f^ SxSI  
} f+Y4~k  
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public void run() io#}z4"'qY  
{ MPB[~#:  
while(nStartPos < nEndPos && !bStop) 7b"fpB  
{ &da=hc,>%  
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try{ *6}M.`.-  
URL url = new URL(sURL); =$'>VPQ  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection ();
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httpConnection.setRequestProperty("User-Agent","NetFox"); NW\C
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String sProperty = "bytes="+nStartPos+"-"; 5H3o?x
 
httpConnection.setRequestProperty("RANGE",sProperty); e;.,x
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Utility.log(sProperty); {5dVK  
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InputStream input = httpConnection.getInputStream(); `D+zX
 
//logResponseHead(httpConnection); Olzw)Wj
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 S!?T0c?>  
byte[] b = new byte[1024]; :;%Jm  
int nRead; BE?]P?r?  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) o
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{
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nStartPos += fileAccessI.write(b,0,nRead); Z '5itN^  
//if(nThreadID == 1) lSX1|,B7:]  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); L.;b(bFe  
}
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Utility.log("Thread " + nThreadID + " is over!"); Y'/6T]a  
bDownOver = true; C*Q7@+&  
//nPos = fileAccessI.write (b,0,nRead); 
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} 5IU!BQU  
catch(Exception e){e.printStackTrace ();} =4_}.  
} 0+\725DJ  
} gPMR,TU  
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//打印回应的头信息 lelmX  
public void logResponseHead(HttpURLConnection con) uaIAVBRcS  
{ 0,hs%x>v  
for(int i=1;;i++) U%vTmdOY  
{ .tRm1&Qi  
String header=con.getHeaderFieldKey(i); xkSXKR  
if(header!=null) @gP
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//responseHeaders.put(header,httpConnection.getHeaderField(header)); S1=P-Ao  
Utility.log(header+" : "+con.getHeaderField(header)); _T)y5/[  
else <F3{-f'Rx  
break; ,6+joKe-  
} R0?bcP&  
} uda++^y:  
2}^=NUM\NX  
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public void splitterStop() Q
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{ }IygU 6{G  
bStop = true; UBd+,]"f  
} 0AM_D >fH  
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} nlv,j&  
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yi8vD~aA[  
/* tw4,gW  
**FileAccess.java _9BL7W $;  
*//文件访问(定位，写) Yc#Uu8f-  
package NetFox; 9R=avfI  
import java.io.*; 5*z>ez2YQ7  
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2|k$Vfz  
public class FileAccessI implements Serializable{ t jM9EP  
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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 C^q|(G)  
RandomAccessFile oSavedFile; $:u*)&"t|  
long nPos; 8~!E.u9w  
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public FileAccessI() throws IOException aR2N,<Cp5  
{ x}2nn)fdZ  
this("",0); NDRDPD  
} |lhnCShw  

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*<\`"C;  
public FileAccessI(String sName,long nPos) throws IOException 21!X[)r  
{ ..yV=idI  
oSavedFile = new RandomAccessFile(sName,"rw"); f`4=Bl&"{  
this.nPos = nPos; 4&E"{d >  
oSavedFile.seek(nPos); 5 3pW:`  
} >33=0<  
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56C8)?  
public synchronized int write(byte[] b,int nStart,int nLen) mAlG}<  
{ ij]UAJ}t  
int n = -1; Dbn~~P  
try{ ]I*RuDv}  
oSavedFile.write(b,nStart,nLen); k_t|) J  
n = nLen; i&DbZ=n2  
} 72$S'O%,0  
catch(IOException e) FH}?QebSR  
{ .]>Tj^1  
e.printStackTrace (); "I56l2dxd  
} >FE8CH!W&  
")8l'^Mq2  
IYn`&jS{  
return n; )B]"""J  
} wXQu%F3  
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} bB4FjC':  
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/* 3nB
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**SiteInfoBean.java p7\LLJ y  
*/ U_VP\ 03  
package NetFox; F,vkk{Z>  
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?Nt(sZ-  
public class SiteInfoBean {  Ht.P670  
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private String sSiteURL; //Site's URL h`U-{VIrqi  
private String sFilePath; //Saved File's Path 7bYwh8  
private String sFileName; //Saved File's Name JOuy_n  
private int nSplitter; //Count of Splited Downloading File 
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public SiteInfoBean() /@ emE0  
{//nSplitter的缺省值为5 W(s5mX,Kv  
//default value of nSplitter is 5 ;tQc{8O6L  
this("","","",5); <IWg]AJT:  
} qBF|' .$^  
9ug4p']  
hV $Zr4'  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) iq3)}hGo  
{ IS"[<  
sSiteURL= sURL; XR]bd  
sFilePath = sPath; ?"'+tZ=f6  
sFileName = sName; &wDZ@{h  
this.nSplitter = nSpiltter; z1b@JCWE  
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<< =cZ.HP  
} hXFT(J=  
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1E$\&*(  
public String getSSiteURL() 7&,$  
{ ZeG4z({af  
return sSiteURL; `(j~b=PP  
} =m<b+@?T  
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public void setSSiteURL(String value) >Ec;6V e  
{ ?9xWTVa8  
sSiteURL = value; 0(o2<d7  
} J#:`'eEG  
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S.[L?uE~F  
public String getSFilePath() xVsI#`<a  
{ h% >ZN-K)  
return sFilePath; XRV~yBIS  
} AxEdQRGk  
oM1C/=8   
X
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public void setSFilePath(String value) N5W!(h)  
{ @u$NB3  
sFilePath = value; R{[v#sF >#  
} pj7al;  
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K:e[#b8:R  
public String getSFileName() S*n5d>;  
{ s Y4wdG  
return sFileName; p%iZ6H>G  
} cY+fZ=  
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public void setSFileName(String value) o5RvxGN  
{ x?rd9c
 
sFileName = value; /\qzTo  
} d lAb`ne  
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public int getNSplitter() ouyZh0G  
{ 'h;qI&  
return nSplitter; .5>]DZn6  
} 63'%+  
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> {d9z9O  
public void setNSplitter(int nCount) ]2ab~ gr  
{ !r6Yq,3  
nSplitter = nCount; [ Y{  
} SnX)&>B  
} ``]NB=N}{1  
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/* ;dfIzi  
**Utility.java \PZ;y=]p}  
*/ ]N\D^`iQ  
package NetFox; K}N~KDW R|  
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D'%M#S0  
public class Utility { 'Sgz\=K  
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public Utility() 'ahz@+lO  
{ vz3olHX  
A:4&XRYZY  
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} nxEC6Vh'  
b%x=7SMXO  
//线程睡眠 d%L/[.&  
public static void sleep(int nSecond) 2zbn8tO  
{ K[?@nl?,z  
try{ N/
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Thread.sleep(nSecond); "5ISKuL  
} 9Y:.v@:}0  
catch(Exception e)  6shN%  
{ 6uUzky  
e.printStackTrace (); } gwfe H
 
} E:uTjXt  
} yW*,Llb5  
!K2QD[x  
//日志 Piw i  
public static void log(String sMsg) O`!XW8  
{ ml)\RL  
System.err.println(sMsg); sUQ Q/F6  
} ,*\s  
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 6cjCn  
public static void log(int sMsg) *q\>DE=7  
{ 3me&isKL  
System.err.println(sMsg); 6~>h;wC  
} o*E32#l  
} > Xij+tt{  
Xwu&K8q21  
j%ZBAk)}  
/* -glGOTk  
**TestMethod.java I!(BwYd  
*/ BaUuDo/ZO  
package NetFox; Q t>|TGz  
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public class TestMethod { 6wbH{}\ll  
3A =\Mb  
.h/2-pQ>  
public TestMethod() owyQFk  
{ ///xx/weblogic60b2_win.exe lqO>Q1_{K  
try{ A@Zqh<,Ud  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); M+j*5wNy  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 8N |K
  
SiteFileFetch fileFetch = new SiteFileFetch(bean); A5\ Hq  
fileFetch.start(); n _x+xVi%  
} p/l">d]+  
catch(Exception e){e.printStackTrace ();} p)z#%BY56  
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} M$!-B,1BX  
j B1ZF#  
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public static void main(String[] args) 6f t6;*,  
{ >Y\?v-^~;  
new TestMethod(); OwNo$b]h`  
} @KHY8y7  
} o!&+ _BKw  
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