http断点续传简单实现（java)

/* "< c,I=A  
**SiteFileFetch.java AWXBk+  
*/ 9/@7NNKJ  
package NetFox; 3Dm`8Xt  
import java.io.*; 3fb"1z#  
import java.net.*; .o&Vu,/H  
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public class SiteFileFetch extends Thread { 7a0kat'\  
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SiteInfoBean siteInfoBean = null; //文件信息Bean   OH*  
long[] nStartPos; //开始位置 (PM!{u=  
long[] nEndPos; //结束位置  MoFAQe  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 -/7[\S  
long nFileLength; //文件长度 XITh_S4fs=  
boolean bFirst = true; //是否第一次取文件 JxV0y  
boolean bStop = false; //停止标志 0+vt LDq@P  
File tmpFile; //文件下载的临时信息 qrK\f  
DataOutputStream output; //输出到文件的输出流 XEB1%. p  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） l?UFe$9(  
public SiteFileFetch(SiteInfoBean bean) throws IOException `F^~*FnR,B  
{ uE}A-\G  
siteInfoBean = bean; {tN?)~ZQ  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); f\{ynC2m  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 3T|xUY)G4  
if(tmpFile.exists ()) $YNWT\
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{ k^Gf2%k  
bFirst = false; RTJ\|#w  
read_nPos(); ):c)$$dn  
} !=Hu?F p  
else e[:i`J2  
{ z+k[HE^S  
nStartPos = new long[bean.getNSplitter()]; J'=iEI  
nEndPos = new long[bean.getNSplitter()]; SdJGhU  
} SFiK_;  
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} \a.^5g  
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public void run() (9phRo)>  
{ u@{z xYn  
//获得文件长度 8q5 `A Gl  
//分割文件 7@6B\':  
//实例FileSplitterFetch [

2 yxTK  
//启动FileSplitterFetch线程 g9XAUZe  
//等待子线程返回 /
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@  
try{ /|HVp  
if(bFirst) t 5{Y'  
{ a#k
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nFileLength = getFileSize(); `/4R$E{  
if(nFileLength == -1) DA(ur'D  
{ /p PSo  
System.err.println("File Length is not known!"); TJhzyJ
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} X;vfbF   
else if(nFileLength == -2) ~:l
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{ *>#mI/#}  
System.err.println("File is not access!"); 'Wv`^{y <^  
} ;L{#TC(]J]  
else EW:tb-%`  
{ Wj}PtQ%lp/  
for(int i=0;i<nStartPos.length;i++) V(5=-8k  
{ |RA|nu   
nStartPos = (long)(i*(nFileLength/nStartPos.length)); &-hz&/A,  
} >B~vE2^tQ~  
for(int i=0;i<nEndPos.length-1;i++) DJ
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{ R'Uw
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nEndPos = nStartPos[i+1]; w~n7l97Pw  
} Ny6 daf3f  
nEndPos[nEndPos.length-1] = nFileLength; 6iZ:0y0t+6  
} ^hN.FIzM  
} }R\9ybv  
9td[^EB#(h  
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//启动子线程 p[&6h

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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; %_>+K;<  
for(int i=0;i<nStartPos.length;i++) \(.])I>)eh  
{ M#U#I:z%  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), J:  T  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), /ad]p
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nStartPos,nEndPos,i); hHoc>S6^M  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); +,H6)'#Z  
fileSplitterFetch.start(); OfAh?^R  
} d ~`_;.z  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ]JUb;B;Z  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); nG+L'SmI  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", wRATe 0'
 
nEndPos = " + nFileLength); $zR[2{bg  
// fileSplitterFetch[nPos.length-1].start(); &AS<2hB  
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//等待子线程结束 Idzr
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//int count = 0; <.N337!  
//是否结束while循环 Y2B",v"  
boolean breakWhile = false; M }H7`
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2!y%nkO*  
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while(!bStop) +I9+L6>UR  
{ i,h)  
write_nPos(); eLd7|*|  
Utility.sleep(500); 4YmN3i  
breakWhile = true; R DAihq  
{TWgR2?{C  
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for(int i=0;i<nStartPos.length;i++) ^&|$&7  
{ 8r 4 L4  
if(!fileSplitterFetch.bDownOver) +EnJyli  
{ ,XZ[L? >  
breakWhile = false; BUozpqN}  
break;
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} DW,fh8w  
} z3lMD'uU3  
if(breakWhile) .-0;:>  
break; wU|Y`wJmF  
"* Qwaq_  
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//count++; NyJ=^=F#  
//if(count>4) e+ZC<Bdh  
// siteStop(); 6-'Y*  
} XP$1CWI  
-i}@o1o\  
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System.err.println("文件下载结束！"); 9=-!~_'1-  
} u}[Z=V  
catch(Exception e){e.printStackTrace ();} zg3q\~  
} f17pwJ~=  
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//获得文件长度 9bpY>ze  
public long getFileSize() 7;_./c_@  
{ `_+j+  
int nFileLength = -1; lIN`1vX(  
try{ zqq$PaH*  
URL url = new URL(siteInfoBean.getSSiteURL()); xV h-Mx+M  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); [}/\W`C  
httpConnection.setRequestProperty("User-Agent","NetFox"); S"Q$ Ol"  
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o,fBOPIN  
int responseCode=httpConnection.getResponseCode(); ^c9~~m16+  
if(responseCode>=400) *d,u)l :S  
{ 9tnW:Nw~  
processErrorCode(responseCode); 8^H <dR  
return -2; //-2 represent access is error 8#Q=CTjF  
} iCouGd}  

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8: KlU(J  
String sHeader; V0]6F  
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for(int i=1;;i++) !2('Cq_^  
{ *lN>RWbM%  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); &k5 Z
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//Utility.log(in.readLine()); T/V 5pYl  
sHeader=httpConnection.getHeaderFieldKey(i); >Ic)RPO9  
if(sHeader!=null) az(u=}  
{ <%(nF+rQA"  
if(sHeader.equals("Content-Length")) F:8cd^d~u  
{ &}1PH%6  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); m|O7@N  
break; 6 ]@H.8+  
} .[-d( #l{l  
} C^po*(W6  
else Q<y&*o3YF|  
break; <B;l).[6  
} %2<G3]6^U  
} ]F@XGJN  
catch(IOException e){e.printStackTrace ();} ^n|u$gIF8  
catch(Exception e){e.printStackTrace ();} _RFTm.9&  
> dJvl|  
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Utility.log(nFileLength); (R*K)(Nw[  
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return nFileLength;
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} k,xY\r$  
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|wKC9O@%  
//保存下载信息（文件指针位置） ;a/Gs^W  
private void write_nPos() Tn+6:<OFdO  
{ 9L}=xX`>?  
try{ i#t)tM
"  
output = new DataOutputStream(new FileOutputStream(tmpFile)); -E4e8'P;5  
output.writeInt(nStartPos.length); 1/Pou)D  
for(int i=0;i<nStartPos.length;i++) \c&%F=1+*  
{ |0?h6  
// output.writeLong(nPos); ).TQYrs  
output.writeLong(fileSplitterFetch.nStartPos); ~+{OSx<S  
output.writeLong(fileSplitterFetch.nEndPos); (u81
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} ^D(N_va<  
output.close(); ,C88%k  
} 3,8>\yf`  
catch(IOException e){e.printStackTrace ();} 5MH\Gqe7  
catch(Exception e){e.printStackTrace ();} ^+
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} swvn*xr  
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//读取保存的下载信息（文件指针位置） nV-A0"z_&  
private void read_nPos() W6t"n_%?"  
{ >!|Hns  
try{ wRL=9/5(8  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 0/d+26lR  
int nCount = input.readInt(); 33lD`4i+  
nStartPos = new long[nCount]; <wge_3W#  
nEndPos = new long[nCount]; ~3Y)o|D3  
for(int i=0;i<nStartPos.length;i++) UdmYS3zs  
{ YFD'&N,sx  
nStartPos = input.readLong();
7z'l}*FRD  
nEndPos = input.readLong(); K.?~@5%  
} ve2GRTO^aC  
input.close(); n$Z@7r  
} #pbPaRJL(  
catch(IOException e){e.printStackTrace ();} ,[}5@cS  
catch(Exception e){e.printStackTrace ();} Gxu&o%x[  
} dUOvv/,FZT  
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private void processErrorCode(int nErrorCode) "q(#,,_  
{ W$7db%qFx  
System.err.println("Error Code : " + nErrorCode); ID"'`DKxe  
} wSHE~Xx  
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D.H$4[u;j  
//停止文件下载 wt4uzg8  
public void siteStop() |;o#-YosP  
{ nS0K&MH6B  
bStop = true; .7TQ
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for(int i=0;i<nStartPos.length;i++) > $0eRVL  
fileSplitterFetch.splitterStop(); "ZDc$v:Qa  
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} 0[@9f1Nk4  
} RKsr}-18  
//负责部分文件的抓取 $:kG>R@\t  
**FileSplitterFetch.java \TSt  
*/ 3!M;Z7qF]  
package NetFox; beFVjVVHq  
rr fL[  
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import java.io.*; nj99!"_  
import java.net.*; @O#4duM4Qz  
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public class FileSplitterFetch extends Thread { h% BA,C  
;hi+.ng_  
#/zPAcV:  
String sURL; //File URL &o$E1;og  
long nStartPos; //File Snippet Start Position euO!+9p  
long nEndPos; //File Snippet End Position Hzs]\%"  
int nThreadID; //Thread's ID |><hdBQXX<  
boolean bDownOver = false; //Downing is over = R|?LOEK+  
boolean bStop = false; //Stop identical )=TD}Xb  
FileAccessI fileAccessI = null; //File Access interface /NCEZ@2BN,  
j?D=Ij"o  

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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException [@Y<:6  
{ de
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this.sURL = sURL; m`!C|?hu  
this.nStartPos = nStart; bj4cW\b(  
this.nEndPos = nEnd; _y&m4Vuu  
nThreadID = id; !4cR&@[  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 E\Hhi.-  
} z5-vx`  
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public void run() ucQ2/B#'4l  
{ Mw2?U>h1  
while(nStartPos < nEndPos && !bStop) es@_6ol.@  
{ ;u!qu$O  
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try{ Uj&2'>MJ$  
URL url = new URL(sURL); B Jp\a7`;  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ?1JVzZ4H  
httpConnection.setRequestProperty("User-Agent","NetFox"); ;Pik},  
String sProperty = "bytes="+nStartPos+"-"; l-4T Tg  
httpConnection.setRequestProperty("RANGE",sProperty); PVvN
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Utility.log(sProperty); '"LrGvkZ  
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+h^>?U,  
InputStream input = httpConnection.getInputStream(); | Zx  
//logResponseHead(httpConnection); X=)Ue  
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byte[] b = new byte[1024]; w!o[pvyR$  
int nRead; ;rWgt!l  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) A\Rkt;:  
{ @.e
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nStartPos += fileAccessI.write(b,0,nRead); v'0A$`w`  
//if(nThreadID == 1) Ovh  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); z?`&HU Nf  
} >oi`%V  
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Utility.log("Thread " + nThreadID + " is over!"); d{2+> >d  
bDownOver = true; 1P(rgn:8e  
//nPos = fileAccessI.write (b,0,nRead); rLO1Sv  
} wjW>#DE  
catch(Exception e){e.printStackTrace ();} so}(*E&(a  
} 6j{9\
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}  pMM,ox"  
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$}&Y$w>S  
//打印回应的头信息 ?#"rI6  
public void logResponseHead(HttpURLConnection con) L A-H  
{ |f1 S&b.  
for(int i=1;;i++) WGFp<R  
{ {pMbkAQ@  
String header=con.getHeaderFieldKey(i); "mc
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if(header!=null) (
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//responseHeaders.put(header,httpConnection.getHeaderField(header)); t98t&YUpm  
Utility.log(header+" : "+con.getHeaderField(header)); s*{l}~fPkW  
else Pn|A>.)z  
break; i-[ic!RnKj  
} xrDHXqH  
} yi*)g0M  
cjfYE]  
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public void splitterStop() M72.  
{ .g71?^?(  
bStop = true; dC8$Ql^<  
} "!()yjy  
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} 8o43J;mA  
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/* KM$Lu2
  
**FileAccess.java /NfuR$oMd  
*//文件访问(定位，写) }SYR)eE\  
package NetFox; /.r|ron:e  
import java.io.*; |kJ'FZZd  
=W'a6)WE  
!gA<9h  
public class FileAccessI implements Serializable{ 1'DD9d{qN  
DXu915  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节
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RandomAccessFile oSavedFile; 6lw)L  
long nPos; Q qGf*  
.%;`:dtj  
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public FileAccessI() throws IOException P34UD:  
{ 7(cRm$)L  
this("",0); 1!_$HA  
} [.Vy  
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|O3wAxc3W  
public FileAccessI(String sName,long nPos) throws IOException 9jq}`$S{  
{ xl [3*K   
oSavedFile = new RandomAccessFile(sName,"rw"); C3q}Dh+]  
this.nPos = nPos; Qgx9JJ>  
oSavedFile.seek(nPos); 9IJBK  
} A+P9M \u.  
\6o%gpUkD  
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public synchronized int write(byte[] b,int nStart,int nLen) B1)gudP`  
{ {3n|=  
int n = -1; JDPn   
try{ V45A>#?U  
oSavedFile.write(b,nStart,nLen); 87WIDr  
n = nLen; ..BIoSrj  
} FOJ-?s(  
catch(IOException e) ybLl[K(D=  
{ 2F*spu  
e.printStackTrace (); 278:5yC  
} kN(*.Q|VZ  
o2M+=O@  
~ 8L]!OQ9=  
return n; T DOOq;+  
} k4:$LFw@  
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} 2;h4$^`dt  
q"){PRTm/  
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/* &V/n!|q<H  
**SiteInfoBean.java vbEAd)*S  
*/ )!SA]>-  
package NetFox; 'fpm] *ig  
|f5WN&c  
32h}+fd  
public class SiteInfoBean { 1;_tu  
7<FI[  
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private String sSiteURL; //Site's URL #dyz  
private String sFilePath; //Saved File's Path ED0\k $  
private String sFileName; //Saved File's Name 7A:k  
private int nSplitter; //Count of Splited Downloading File Do1 Ip&X  
.
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g7\MFertR^  
public SiteInfoBean() |v,%!ps  
{//nSplitter的缺省值为5 9N1Uv,OtB  
//default value of nSplitter is 5 {A!1s;  
this("","","",5); -u
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} =' %r"_`}  
\j C[|LM&  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ogD 8qrZ6J  
{ dH]0(aJ  
sSiteURL= sURL; Z;M}.'BE  
sFilePath = sPath; FuqMT`  
sFileName = sName; {qxFRi#\k  
this.nSplitter = nSpiltter; WX.6|  
sVXIR  
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} x=-dv8N?  
=NJ:%kvF  
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public String getSSiteURL()

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{ %[3?vX  
return sSiteURL; HC1jN8WDY  
} Ot,
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R=Qa54  
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public void setSSiteURL(String value) 4pU|BL\j  
{ :+?eF^5  
sSiteURL = value; KWuc*!  
} Eo h4#fZ\N  
,_SE!iL  
#B_Em$  
public String getSFilePath() 8ckcTNPu  
{ _6U=7<f  
return sFilePath; vP k\b 3E  
} Ug}dw a  
Sr$&]R]^  
-@*[   
public void setSFilePath(String value) >.sdLA Si  
{ *=yUs'brB  
sFilePath = value; F7o#KN*.]  
} M:[rH  
\/qo2'V j`  
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public String getSFileName() ^)i5.o\  
{ :eHD{=  
return sFileName; A(Tqf.,G  
} i^<P@ |q  
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whH_<@!  
public void setSFileName(String value) JXT%@w>I  
{ RC[mpR;2  
sFileName = value; <[*%d~92z  
} ,Z3 (`ftC  
B7'rbc'  
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public int getNSplitter() 2Ra}&ie  
{ R=7,F6.  
return nSplitter; nky%Eb[\  
} Re[x$rw  
 !' }  
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public void setNSplitter(int nCount) _%r+?I  
{ 62-,!N 1-  
nSplitter = nCount; *
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} to2#PXf]y  
} ejFGeR  
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HQ187IwpTm  
/* n0\k(@+k  
**Utility.java r%:Q(|v?  
*/ X=1Po|  
package NetFox; s%cfJe_k  
/ 5\gP//9K  
7O.?I# 76  
public class Utility { t[r<&1[&  
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public Utility() . X:
 
{ ]J '#KT{  
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} +VSq[P  
jV|j]m&t  
//线程睡眠 |>'.(
 
public static void sleep(int nSecond) 13JZ\`ceb  
{ *ku}.n  
try{ _L^(CFE  
Thread.sleep(nSecond); 8*bEsc|  
} /W|=Or2oR  
catch(Exception e) TA9Kg=_  
{ 1WP(=7$.  
e.printStackTrace (); av8\?xmo.$  
} ^ ,cwm:B@  
} RV=Z$  
uY_vX\;67z  
//日志 nt:d,H<p  
public static void log(String sMsg) @H83Ad  
{ bb4
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System.err.println(sMsg); 0[ BPmO6  
} t@#l0lu$  
gs:V4$(p4  
mVs<XnA47  
public static void log(int sMsg) @CB&*VoB  
{ i"_@iN0N  
System.err.println(sMsg); K*/X{3J;  
} c/'Cju W  
} Iq?#kV9)  
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/* >WZ_) `R  
**TestMethod.java 6OPYq*|  
*/ ,_
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package NetFox; >^Z==1  
F,.dC&B
 
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public class TestMethod { ~u.((GM  
+7V4mF!u  
i]
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public TestMethod() >qL-a*w:a  
{ ///xx/weblogic60b2_win.exe 2R`dyg  
try{ ?= RC?K  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 2mt S\bAF  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); >D5WAQ>b  
SiteFileFetch fileFetch = new SiteFileFetch(bean); + e3{J_  
fileFetch.start(); 3;'RF#VL  
} DGJt$o=&@  
catch(Exception e){e.printStackTrace ();} |Bhj L,  
<tn6=IV  
n7p,{KSQ  
} pIhy3@bY  
?l/+*/AR;  
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public static void main(String[] args) 4Q?3gA1  
{ @s%!R  
new TestMethod(); 9`FPV`/  
} 5faY{;8  
} v*lj>)L  
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