http断点续传简单实现（java)

/* #]nH
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**SiteFileFetch.java B+:'Ld](  
*/ jYAD9v%  
package NetFox; KiXXlaOs  
import java.io.*; 'J+dTs;0  
import java.net.*; B j!{JcM-^  
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public class SiteFileFetch extends Thread { mjdZ^  
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SiteInfoBean siteInfoBean = null; //文件信息Bean Q v/}WnBk  
long[] nStartPos; //开始位置 YVy+1q[  
long[] nEndPos; //结束位置 C3|(XChqC  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ;>?
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long nFileLength; //文件长度 _tE`W96J  
boolean bFirst = true; //是否第一次取文件 PprCz
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boolean bStop = false; //停止标志 <"I#lib  
File tmpFile; //文件下载的临时信息 OhT?W
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DataOutputStream output; //输出到文件的输出流 n[#!Q`D  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） STMc@MeZU_  
public SiteFileFetch(SiteInfoBean bean) throws IOException ?nOul}y/  
{ --SlxV/x  
siteInfoBean = bean; n6T@A;_g  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); iU^
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tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 6onFf* m!x  
if(tmpFile.exists ()) b/N+X}VMN  
{ >;Er[Rywr  
bFirst = false; mSSDV0Pfn  
read_nPos(); `TvpKS5.Y  
} ^6=y4t=%F  
else Y*
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{ H.sHXuu  
nStartPos = new long[bean.getNSplitter()]; 9Xw(|22  
nEndPos = new long[bean.getNSplitter()];
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} d`>'<  
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} O)g\/uRy  
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public void run() octBt`\Of  
{ Ba$&4?8  
//获得文件长度 HIUB:  
//分割文件 4(5NHsvp  
//实例FileSplitterFetch W0GDn  
//启动FileSplitterFetch线程 qx3@]9  
//等待子线程返回 ?Rlo<f:Mf  
try{ @1_M's;  
if(bFirst) <-xI!o"}  
{ 2l5>>yY  
nFileLength = getFileSize(); &S/@i|_  
if(nFileLength == -1) sem:"  
{ tOx)t$ix  
System.err.println("File Length is not known!"); nH*JR  
} .(T*mk*>  
else if(nFileLength == -2) p^u;]~JO  
{ 1"pvrX}  
System.err.println("File is not access!"); 3o=R_%r  
} .W[ 9G\  
else hV,)u3  
{ %fY\vd2  
for(int i=0;i<nStartPos.length;i++) Y.9s-g  
{ 7`113`1  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); WP/?(%#Y  
} 8KH|:>s=  
for(int i=0;i<nEndPos.length-1;i++) y\M]\^[7  
{ #bN'
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nEndPos = nStartPos[i+1]; DEj6 ky  
} @LQe[`  
nEndPos[nEndPos.length-1] = nFileLength; !zc?o?~z  
} WCc7 MK  
} C"`,?K(U  
Bp #:sAG  
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//启动子线程 b^WTX  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; UVND1XV^f  
for(int i=0;i<nStartPos.length;i++) xaQO=[  
{ y7a84)j3  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 8|FHr,  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ''Lf6S`4X~  
nStartPos,nEndPos,i); ?)x"+[2  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); K"lZwU\:On  
fileSplitterFetch.start(); v#yeiE4  
} pP JhF8Dt  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 9 b?Nlk8d  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ^*!Tq&Dst|  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", <#c/uIN  
nEndPos = " + nFileLength); 2`2S94'  
// fileSplitterFetch[nPos.length-1].start(); ;3~+M:{2  
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//等待子线程结束 "n,?)  
//int count = 0; y2nwDw(xF  
//是否结束while循环 Pe-1o#7~W  
boolean breakWhile = false; >M~wFs$~  
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while(!bStop) &x= PAu  
{ t|/{oAj  
write_nPos(); d~ m,hCTe  
Utility.sleep(500); (c^ZFh2]  
breakWhile = true; h!>K[*  
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for(int i=0;i<nStartPos.length;i++) ExJch\  
{ ix.I)  
if(!fileSplitterFetch.bDownOver) [^rMM1^,OB  
{ (P=q&]l[  
breakWhile = false; j>D[iHrH  
break; wtm=  
} v'fX'/  
} Dht,!LVb;  
if(breakWhile) `dp]N0nz  
break; YwYCXFQ|  
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2m! T.$  
//count++; Tj[=E  
//if(count>4) xfAnZBsVo  
// siteStop(); |3ob1/)p0  
} *3A`7usU  
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System.err.println("文件下载结束！"); M.*3qWM  
} 5!tiu4LU  
catch(Exception e){e.printStackTrace ();} 2.6F5&:($  
} "$@Wy,yp  
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//获得文件长度 !Z0p94L  
public long getFileSize() iS/faXe5  
{ #KFpT__F  
int nFileLength = -1; xzI?'?duC  
try{ mmf}6ABYT  
URL url = new URL(siteInfoBean.getSSiteURL()); XkGS3EY  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); .YYLMI  
httpConnection.setRequestProperty("User-Agent","NetFox"); J.t tJOP  
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int responseCode=httpConnection.getResponseCode(); =Su~iOa  
if(responseCode>=400) n#
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{ N51g<K  
processErrorCode(responseCode); xoT|fgb  
return -2; //-2 represent access is error VH>?%aL  
} .UdoB`@!v=  
1
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String sHeader; +?&|p0  
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for(int i=1;;i++) *F_ dP
  
{ nKR=/5a4Y  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 6/4?x)l3-  
//Utility.log(in.readLine()); y
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sHeader=httpConnection.getHeaderFieldKey(i); vc r5  
if(sHeader!=null) /a'cP  
{ \os iY^  
if(sHeader.equals("Content-Length")) 5:T)hoF@  
{ MhaoD5*9  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ~WKcO&  
break; 94Hs.S)  
} "{1SDbwmMo  
} $t1XoL  
else Z` ;.62S  
break; -C  
} s\Zp/-Q  
} :)PAj  
catch(IOException e){e.printStackTrace ();} Bkq3-rX\  
catch(Exception e){e.printStackTrace ();} ea\b7a*  
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Utility.log(nFileLength); xklXV  
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return nFileLength; Y+[Z,   
} qRX:eo  
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//保存下载信息（文件指针位置） {&qB!axj  
private void write_nPos() VQMPs{tm  
{ !(&N
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try{ v[}g+3a  
output = new DataOutputStream(new FileOutputStream(tmpFile)); \/ 9s<  
output.writeInt(nStartPos.length); s?}m~Pl  
for(int i=0;i<nStartPos.length;i++) sz?/4tY
 
{ ~?BN4ptc  
// output.writeLong(nPos); yn;sd+:z  
output.writeLong(fileSplitterFetch.nStartPos); S,'y L7s  
output.writeLong(fileSplitterFetch.nEndPos); =Y-ZI  
} N8-!}\,  
output.close(); bq}hj Cy  
} ^kF-mM=  
catch(IOException e){e.printStackTrace ();} }2X"  
catch(Exception e){e.printStackTrace ();} *pZhwO!D  
} lY,dy
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//读取保存的下载信息（文件指针位置） X / {;  
private void read_nPos() 9pPohR*#V  
{ GK>.R<[
 
try{ iW\Q>~0#_  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); kzUP   
int nCount = input.readInt(); REaU=-m-  
nStartPos = new long[nCount]; ~\C.Nm  
nEndPos = new long[nCount]; Js'#=  
for(int i=0;i<nStartPos.length;i++) g6wL\g{29  
{ 4|EV`t}EV  
nStartPos = input.readLong(); eX1<zzd  
nEndPos = input.readLong(); Vw P+tM  
} <,Z6=M
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input.close(); _rmTX.'w  
} mh8{`W&  
catch(IOException e){e.printStackTrace ();}  ?[`*z?}  
catch(Exception e){e.printStackTrace ();} WF!u2E+  
} Kj+=?R~}S  
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private void processErrorCode(int nErrorCode) .8I\=+Zi  
{ T*'?;u  
System.err.println("Error Code : " + nErrorCode); %~$P.Zh  
} >3J?O96|f  
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//停止文件下载 B>!OW2q0D  
public void siteStop() G[[hC[}I  
{ ;hcOD4or  
bStop = true; uv}?8$<\  
for(int i=0;i<nStartPos.length;i++) -76l*=|  
fileSplitterFetch.splitterStop(); }0%~x,  
 oRbG6Vv/  
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} :hA=(iz  
} |hlc#t?  
//负责部分文件的抓取 <691pkX  
**FileSplitterFetch.java 6n  
*/ R54wNm@  
package NetFox;  Q9!T@
 
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import java.io.*; %( tu<  
import java.net.*; 2L!wbeTb;  
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public class FileSplitterFetch extends Thread { Ns*&;x9  
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String sURL; //File URL :|P[u+v  
long nStartPos; //File Snippet Start Position Tw{}Ht_Qq  
long nEndPos; //File Snippet End Position v_7?Zik8E  
int nThreadID; //Thread's ID n&j@7R  
boolean bDownOver = false; //Downing is over O8\dMb  
boolean bStop = false; //Stop identical =jWcD{;1I}  
FileAccessI fileAccessI = null; //File Access interface 63EwV p/|  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException #KOr-Yg|U  
{ LZ?z5U:  
this.sURL = sURL; ";PW#VHC  
this.nStartPos = nStart; .*3.47O  
this.nEndPos = nEnd; Bj-80d,  
nThreadID = id; lO=Nw+'$S  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 `ecIy_O3P&  
} v*&WxP^Gm  
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public void run() bu j}pEI  
{ 9MI~yIt`L  
while(nStartPos < nEndPos && !bStop) M`~UH\  
{ g<@P_^vo  
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try{ LxcC5/@\~(  
URL url = new URL(sURL); VD,p<u{r  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); \m\E*c ):  
httpConnection.setRequestProperty("User-Agent","NetFox"); PqhR^re0.  
String sProperty = "bytes="+nStartPos+"-"; %O=U|tuc$  
httpConnection.setRequestProperty("RANGE",sProperty); WaaF;|,(  
Utility.log(sProperty); 2EU((Q`>=(  
 3)bC,  
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InputStream input = httpConnection.getInputStream(); O:'ENoQ:&  
//logResponseHead(httpConnection); gHB*u!w7Z  
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byte[] b = new byte[1024]; !sJ*0  
int nRead; ;g:!WXd  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) !P_8D*
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{ h.~:UR*   
nStartPos += fileAccessI.write(b,0,nRead); Zs$Qo->F  
//if(nThreadID == 1)  x+=Ko  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); C'_^DPzj  
} ;F/yS2p  
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Utility.log("Thread " + nThreadID + " is over!"); d&@>P&AT  
bDownOver = true; lVw77bZ  
//nPos = fileAccessI.write (b,0,nRead); ;aY.CgX  
} MPtn$@  
catch(Exception e){e.printStackTrace ();} doERBg`Jh  
} MHm=X8eg  
} x$
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//打印回应的头信息 aLWNqe&1  
public void logResponseHead(HttpURLConnection con) swfcA\7R  
{  3Y L  
for(int i=1;;i++) ?bq S{KF  
{ us_o{  
String header=con.getHeaderFieldKey(i); U@6bH@v5  
if(header!=null) Ji#"PE/Pt  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); \h#,qTE  
Utility.log(header+" : "+con.getHeaderField(header)); XVlZ:kz  
else }:b6WN;c  
break; "\n,vNk  
} 0c$0<2D%  
} 0Bo7EV  
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public void splitterStop() _0v+g1x  
{ w[WyT`6h!  
bStop = true; 6<uJ}3  
} 8@}R_GZc  
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} {x-iBg9#l2  
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/* #]~l]Eq  
**FileAccess.java &8##)tS(y  
*//文件访问(定位，写) Y/3CB  
package NetFox; 5Oa`1?C1  
import java.io.*; NB["U"1[^E  
RW?F{Jy{  
 wfecM(  
public class FileAccessI implements Serializable{ 7M|!
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 R>r@I_  
RandomAccessFile oSavedFile; 5`!Bj0Uf  
long nPos; ^tw\F7  
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public FileAccessI() throws IOException ')bas#=uP  
{ HFtl4P  
this("",0); ed=pRb  
} =J2cX`  
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public FileAccessI(String sName,long nPos) throws IOException 3y[uH'  
{ x344}\  
oSavedFile = new RandomAccessFile(sName,"rw"); zKY 9'y  
this.nPos = nPos; f>*D@TrU  
oSavedFile.seek(nPos); 3N5un`K7  
} y4V~fg;  
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public synchronized int write(byte[] b,int nStart,int nLen) J'Z!`R|  
{ MHuQGc"e+4  
int n = -1; 'aWrjfD
y:  
try{ 9*thqs3J#d  
oSavedFile.write(b,nStart,nLen); g
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n = nLen; 4*)a3jI?  
} MRI`h.  
catch(IOException e) s_/a1o  
{ e[Tu.$f-  
e.printStackTrace (); jHU5>Gt-}  
} ja<!_^h=At  
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return n; E`"<t:RzF  
} g`2DJi&)  
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} cl`!A2F1G#  
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/* ~6<'cun@x  
**SiteInfoBean.java :EkhF6B/  
*/ cE|Z=}4I7  
package NetFox; c2tf7fkH  
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s`Y8&e.Yr  
public class SiteInfoBean { -msfiO  
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private String sSiteURL; //Site's URL ;cFlZGw   
private String sFilePath; //Saved File's Path T3JM8  
private String sFileName; //Saved File's Name 2b[R^O}   
private int nSplitter; //Count of Splited Downloading File z-J?x-<  
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public SiteInfoBean() K[.*8  
{//nSplitter的缺省值为5 6]Vf`i  
//default value of nSplitter is 5 8iB}gHe9  
this("","","",5); ]1^F  
} ~ ~"qT  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ik;S!S\
v  
{ ,sOdc!![  
sSiteURL= sURL; k)a3j{{  
sFilePath = sPath; vg.K-"yQW  
sFileName = sName; |e]2 >NjQa  
this.nSplitter = nSpiltter; #77p>zhY  
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} zFFip/z\  
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public String getSSiteURL() 5C
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{ ~vL`[J
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return sSiteURL; O1 KT  
} Z ZMz0^V  
I?z*.yA*  
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public void setSSiteURL(String value) KysJ3G.k
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{ )J"*[[e  
sSiteURL = value; >$g+Gx\v4  
} =Qf.  
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public String getSFilePath() ]9 ArT$
 
{ D2@J4;UW*W  
return sFilePath; 8M_p'AR\,y  
} )[Bl3+'  
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public void setSFilePath(String value) *oW^P~m/  
{ s (hJ *
  
sFilePath = value; '1Z3MjX  
} S{l >|N2q  
c:@lR/oe"  
8etNS~^  
public String getSFileName() !
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{ Jq1^}1P  
return sFileName; v!~;QO  
} mjI $z3  
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mT3'kUZ}]  
public void setSFileName(String value) VOa7qnh4:[  
{ #K4lnC2qz  
sFileName = value; >}p'E9J?r  
} jW!x!8=  
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public int getNSplitter() c[6=&  
{ Rr!oT?6J?  
return nSplitter; ^]_5oFRIj  
} DEFh&n  
/+p]VHP\  
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public void setNSplitter(int nCount) kvoEnwBe_  
{ Tl%n|pc  
nSplitter = nCount; 8euh]+  
} IuW5LS  
} 8#_"WzDw  
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/* 8K;wX%_,  
**Utility.java h88IP:bo  
*/ Y;B#_}yF  
package NetFox; f'-) 3T  
8A,="YIt  
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public class Utility { Qt VZ)777
 
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public Utility() NA<6s]Cs.  
{ gT=RJB  
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} wvuh   
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//线程睡眠 J_tI]?jrU  
public static void sleep(int nSecond) l4
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{ U*R  
try{ }w
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Thread.sleep(nSecond); &l| :1  
} ->0OqVQA  
catch(Exception e) oKlOcws}  
{ :{tj5P!S  
e.printStackTrace (); g218%i  
} $At,D.mGkb  
} 8ba*:sb  
iJsa;|2/  
//日志 ud@7%%  
public static void log(String sMsg) +P//p$pE
 
{ aN}l&4d  
System.err.println(sMsg); L3 VyW8Y  
} ;^cc-bLvF  
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lDd8dT-Q.  
public static void log(int sMsg) ,2y" \_  
{ 1qgzb  
System.err.println(sMsg); (8?5REz  
} w]Fi:kV  
} _;x7vRWmN  
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5(}Qg9%  
/* A!\-e*+W=  
**TestMethod.java GSh~j-C'  
*/ AWqc?K@   
package NetFox; (q|EC;  
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public class TestMethod { SA'c}gP  

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public TestMethod() k
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{ ///xx/weblogic60b2_win.exe 5 Y|
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try{ Ksu_4dE  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); /t<C_lLM  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); J BN_Upat  
SiteFileFetch fileFetch = new SiteFileFetch(bean); TiF2c#Q*y  
fileFetch.start(); ]*Tnu98G}  
} =C[2"Y4JK0  
catch(Exception e){e.printStackTrace ();} Nsd7?|@HI  
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} UVIR P#  
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Wz^M*=,  
public static void main(String[] args) K#LG7faj  
{ =yZiBJ  
new TestMethod(); w'-J24>=  
} EEJsNF  
} J% t[{  
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