http断点续传简单实现（java)

/* 'EET3RK-S  
**SiteFileFetch.java Bd~cY/M  
*/ jl-Aos"/  
package NetFox; JBEgiQ/  
import java.io.*; W%9K5(e  
import java.net.*; zo7XmUI3P  
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public class SiteFileFetch extends Thread { u$=ogp=0  
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SiteInfoBean siteInfoBean = null; //文件信息Bean '}pgUh_  
long[] nStartPos; //开始位置 ' raB  
long[] nEndPos; //结束位置 iVi3 :7*  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Pn'(8bRm  
long nFileLength; //文件长度 (GcKaUg8*  
boolean bFirst = true; //是否第一次取文件 nB@iQxcz  
boolean bStop = false; //停止标志 $:BK{,\  
File tmpFile; //文件下载的临时信息 _[vdY|_  
DataOutputStream output; //输出到文件的输出流 Lr}b,  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） eMl]td rI  
public SiteFileFetch(SiteInfoBean bean) throws IOException ^c0$pqZ}r  
{ y.*=Ww+  
siteInfoBean = bean; kuj12  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); KjwY'aYwr:  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); %][$y7  
if(tmpFile.exists ()) [X">vaa  
{ Op/79]$  
bFirst = false; H(N
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read_nPos(); 5hH6G  
} AXh3LA  
else L740s[,`o#  
{ Jm(&G  
nStartPos = new long[bean.getNSplitter()]; Q f+p0E;  
nEndPos = new long[bean.getNSplitter()]; }EedHS  
} Ng'Z
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} &J^4Y!gt  
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public void run() yXTK(<'  
{ -q&7J' N  
//获得文件长度 "0H56#eW  
//分割文件 oWx_O-_._  
//实例FileSplitterFetch R7B,Q(q2-  
//启动FileSplitterFetch线程 :e&n.i^  
//等待子线程返回 gVnw
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try{ KM6N'x^z  
if(bFirst) Y1fy2\<'  
{ @k+%y'Y?  
nFileLength = getFileSize(); q M_/  
if(nFileLength == -1) ne"?90~  
{ oGJ*Rn)Z  
System.err.println("File Length is not known!"); W%>i$:Qq  
} ,5\2C{  
else if(nFileLength == -2) KZrMf77=  
{ iF [?uF  
System.err.println("File is not access!"); 4z9#M;qT  
} c:ll
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else =CjNtD2]  
{ z;y^t4 ^9  
for(int i=0;i<nStartPos.length;i++) YXX36  
{ J+71FP`ZH  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); -3G 4vRIo  
} 97(Xu=tX  
for(int i=0;i<nEndPos.length-1;i++) S$jV|xKB  
{ <}EV*`w4  
nEndPos = nStartPos[i+1]; tM^;?HL]  
} *gd?>P7\0  
nEndPos[nEndPos.length-1] = nFileLength; <Qcex3  
} )+n,5W  
} JQ"`9RNb  
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BKC7kDK3H  
//启动子线程 cebs.sF:  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; gV"qV  
for(int i=0;i<nStartPos.length;i++) `dv}a-Q)c  
{ /ojO>Y[<   
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Sa;<B:|  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), t;.^K\S4  
nStartPos,nEndPos,i); @K$VV^wp  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); %@lV-(5q  
fileSplitterFetch.start(); Lj&1K~U  
} n5Nan  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), :!JpP R5  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); _{LN{iqDv  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", yn/?= ?0  
nEndPos = " + nFileLength); I*A0?{  
// fileSplitterFetch[nPos.length-1].start(); 3Q'[Ee2-3  
}W:*aU  
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//等待子线程结束
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//int count = 0; E0"10Qbi  
//是否结束while循环 I 1b  
boolean breakWhile = false; $J QWfGwR  
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while(!bStop) q&X
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{ M.ZEqV+
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write_nPos(); jWH{;V&ZV  
Utility.sleep(500); f^W[;w  
breakWhile = true; E?30J3S  
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for(int i=0;i<nStartPos.length;i++) r0\cc6  
{ ?EI'^xg  
if(!fileSplitterFetch.bDownOver) lLuID  
{ de> ?*%<  
breakWhile = false; .:}.b"%m  
break; #ZG3|#Q=L  
} <y@,3DD3A9  
} p91`<>Iw  
if(breakWhile) |@ikx{W  
break; Vbg10pV0  
q} ]'Q -  
$ A-+E\vQ@  
//count++; JDLTOLG  
//if(count>4) &w+;N5}3  
// siteStop(); slU  
} 51I|0ly  
;mDM5.iF  
i 8l./Yt/  
System.err.println("文件下载结束！"); XB0a dp  
} &|v{#,ymeb  
catch(Exception e){e.printStackTrace ();} h ?uqLsRl  
} 06 QU  
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5]
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//获得文件长度 )O,wRd>5  
public long getFileSize() 2Y400  
{ >(hSW~i~  
int nFileLength = -1; N>
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try{ S8 :"<B)  
URL url = new URL(siteInfoBean.getSSiteURL()); &J8Z@^  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); uxWFM $  
httpConnection.setRequestProperty("User-Agent","NetFox"); V,V*30K5  
6}ce1|mkg/  

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int responseCode=httpConnection.getResponseCode(); 1hl
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if(responseCode>=400) B\\6#  
{ Lp_$?MCD.  
processErrorCode(responseCode); `/z_rqJ0CL  
return -2; //-2 represent access is error k@#5$Ejc2  
} EE+`i%  
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 s[3e=N  
String sHeader; $:Rn;  
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for(int i=1;;i++) 4|`Yz%'  
{ )h#]iGVN}  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); h@=7R  
//Utility.log(in.readLine()); puOC60zI  
sHeader=httpConnection.getHeaderFieldKey(i); K*
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if(sHeader!=null) _@Y"$V]=Vt  
{ n5|l|#c$N  
if(sHeader.equals("Content-Length")) COR;e`%,  
{ Jlp<koy  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); mw_ E&v  
break; VZ$=6CavH  
} ^$!987"  
} WvujcmOf  
else %m9CdWb=w  
break; Bs[nV}c>>  
} wuA
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} P''X_1oMC  
catch(IOException e){e.printStackTrace ();} +noZ<KFW "  
catch(Exception e){e.printStackTrace ();} S=' wJ@?;
 
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Utility.log(nFileLength); oK2pM18  
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return nFileLength; 2R]&v;A  
} 9M_(He -  
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6SVqRD<`  
//保存下载信息（文件指针位置） 6xoq;=o  
private void write_nPos() EM@;3.IO  
{ ibJHU@l  
try{ -T7xK/  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 4[TR0bM%  
output.writeInt(nStartPos.length); 7{f_fkbs  
for(int i=0;i<nStartPos.length;i++) [*)Z!
)  
{ ZPHXzi3j  
// output.writeLong(nPos); b
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output.writeLong(fileSplitterFetch.nStartPos); c"7j3/p  
output.writeLong(fileSplitterFetch.nEndPos); V }>n  
} rz%<AF Z  
output.close(); \ p4*$  
} -?<4Og[^  
catch(IOException e){e.printStackTrace ();} V >Hf9sZ  
catch(Exception e){e.printStackTrace ();} ;#TaZN  
} l?
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//读取保存的下载信息（文件指针位置） (DDyK[t+VX  
private void read_nPos() *XbI#L%>  
{ w(j^ccPD  
try{ mf' ]O,  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); eWvo,

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int nCount = input.readInt(); @m~RtC-Q  
nStartPos = new long[nCount]; ?7jg(`Yh  
nEndPos = new long[nCount]; QK; T~ _k  
for(int i=0;i<nStartPos.length;i++) 0)|Q6*E>  
{ w%dL8k  
nStartPos = input.readLong(); PmR*}Aw  
nEndPos = input.readLong(); Ri#H.T<'  
} B@O@1?c[  
input.close(); <*|?x86~  
} #`;/KNp 9  
catch(IOException e){e.printStackTrace ();} WZZ4]
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catch(Exception e){e.printStackTrace ();} 1zftrX~v!X  
} ~9=aT1S|  
w8iR|TV  
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private void processErrorCode(int nErrorCode) FB:<zmwR  
{ #z!^<,  
System.err.println("Error Code : " + nErrorCode); aRJcSV  
} 5\F
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hXn3,3f3oZ  
//停止文件下载 YE}s  
public void siteStop() @]HXP_lyD/  
{ w!SkWS b,~  
bStop = true; l&$$w!n0w  
for(int i=0;i<nStartPos.length;i++) T[?6[,.  
fileSplitterFetch.splitterStop(); PUdM[-zjh  
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} M
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} xd-XWXc  
//负责部分文件的抓取 9}29&O  
**FileSplitterFetch.java BVw Wj-,  
*/ (k`{*!:1a  
package NetFox;
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import java.io.*; q o 1lj"P  
import java.net.*; HKO739&n}  
!@A#=(4R4  
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public class FileSplitterFetch extends Thread { 7=XL!:P  

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String sURL; //File URL ILw
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long nStartPos; //File Snippet Start Position otJ!UfpR8  
long nEndPos; //File Snippet End Position aj\nrD1  
int nThreadID; //Thread's ID =~KsS}`1,  
boolean bDownOver = false; //Downing is over !yOeW0/2[  
boolean bStop = false; //Stop identical SC &~s
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FileAccessI fileAccessI = null; //File Access interface jJZgK$5+  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException %\$;(#h  
{ B>y9fI
  
this.sURL = sURL; jZoNi  
this.nStartPos = nStart; }/P5>F<H[  
this.nEndPos = nEnd; 7piuLq+  
nThreadID = id; !T,AdNa8  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 8}e,%
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} ul f2vD  
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public void run() {yA$V0`N{  
{ Q&'}BeUbm  
while(nStartPos < nEndPos && !bStop) JRMM?y  
{ Wu6<\^A  
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try{ Q7X3X,  
URL url = new URL(sURL); B[4pX +f  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); {<>K]P~wD  
httpConnection.setRequestProperty("User-Agent","NetFox"); sOCs
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String sProperty = "bytes="+nStartPos+"-"; WY:&
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httpConnection.setRequestProperty("RANGE",sProperty); in`aGFQO  
Utility.log(sProperty); &sXRN&Fp  
<#GB[kQa  
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InputStream input = httpConnection.getInputStream(); 6[E|
 
//logResponseHead(httpConnection); F0vM0e-  
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byte[] b = new byte[1024]; '})0!g<Y  
int nRead; P|tNL}2`;  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) `+:.L>5([  
{ !HeSOzN  
nStartPos += fileAccessI.write(b,0,nRead); G`fC/Le  
//if(nThreadID == 1) /walu+]h  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); *+'2?*  
} (+<1*5BEkT  
)Or.;  
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Utility.log("Thread " + nThreadID + " is over!"); [Y
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bDownOver = true; &N~ZI*^  
//nPos = fileAccessI.write (b,0,nRead); UO*Ymj 1  
} [%Bf< J<  
catch(Exception e){e.printStackTrace ();} bwM@/g%DL  
} !o=U19)  
} }]n$ %g(  
+Q=1AXe  
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//打印回应的头信息 l {jmlT  
public void logResponseHead(HttpURLConnection con) ?{w3|Ef&  
{ -Y Bd, k3  
for(int i=1;;i++) 'bld,Do6  
{ *KY=\ %D  
String header=con.getHeaderFieldKey(i); hQ6a~?f  
if(header!=null) .h&k jD  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ;$Y4xM`=m  
Utility.log(header+" : "+con.getHeaderField(header)); l\M_-:I+4  
else  z@|GC_L  
break; ;,i]w"*  
} i wxVl)QL  
} )[mwP.T=  
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public void splitterStop() "s!7dKXI"  
{ kr$b^"Ku  
bStop = true; jdE5~a+  
} -C(
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} YEkh3FrbwH  
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/* '>$]{
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**FileAccess.java MX4]Vpv  
*//文件访问(定位，写) s&\I=J.  
package NetFox; B+^(ktZp@  
import java.io.*; \AL f$88>@  
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public class FileAccessI implements Serializable{ Mu'8;9_6  
pdJ/&ufh  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ;nC.fBu  
RandomAccessFile oSavedFile; V=fEPM  
long nPos; <mi-}s  
S=_vv)6+4  
2z\zh[(w  
public FileAccessI() throws IOException z'uK3ng\hH  
{ HB Iip?  
this("",0); l;y7]DO  
} O6IB. >T  
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public FileAccessI(String sName,long nPos) throws IOException >^XBa*4;Y  
{ P/EM :  
oSavedFile = new RandomAccessFile(sName,"rw"); J|'7_0OAx  
this.nPos = nPos; Ut$;ND.-  
oSavedFile.seek(nPos); kP/M<X"  
} v1a6?-  
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public synchronized int write(byte[] b,int nStart,int nLen) dnV[ P  
{ 
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int n = -1; Or !+._3i  
try{ .U T@p  
oSavedFile.write(b,nStart,nLen); 8]&i-VFof  
n = nLen; Q{B}ef  
} M33_ja+L  
catch(IOException e) /-bO!RTwf  
{ aW!@f[%~F  
e.printStackTrace (); 
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} JK.ZdY%  
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^bEc6`eE  
return n; L%>n>w  
} R(n^)^?  
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} <7-J0btV  
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/* detwa}h[0  
**SiteInfoBean.java f4L`.~b'hb  
*/ TEDAb>  
package NetFox; rj6#
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$H+VA@_  
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public class SiteInfoBean { LBF 1;zjK  
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private String sSiteURL; //Site's URL 'uq#ai[5I  
private String sFilePath; //Saved File's Path 4.IU!.Uo  
private String sFileName; //Saved File's Name ;|UF)QGa2  
private int nSplitter; //Count of Splited Downloading File bQ~j=\[r  
sg+uBCGB  
}1>[  
public SiteInfoBean() 2(/g}  
{//nSplitter的缺省值为5 i+gQE!  
//default value of nSplitter is 5
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this("","","",5); ,\qs4&  
} ;]_o4e6\p  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 44-
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{ <vXGi  
sSiteURL= sURL; 8P=o4lO+  
sFilePath = sPath; 
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sFileName = sName; OK\A</8r  
this.nSplitter = nSpiltter; w: >5=mfk  
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q7"7
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} =2@
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public String getSSiteURL() 1
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{ qu|B4?Y/CR  
return sSiteURL; .|/~op4;  
} "_`F\DGAZu  
$^@)  
wQRZ"ri,  
public void setSSiteURL(String value) L:9F:/G  
{ &LbJT$}V  
sSiteURL = value; !ET~KL!  
} [ :zO}
r:  
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public String getSFilePath() [o?*"c  
{ p1vp8p
 
return sFilePath; $ aUo aI  
} 48Mp
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public void setSFilePath(String value) ~V$|i"  
{ \|K;-pL  
sFilePath = value; U
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} c 9jGq  
$ibuWb"a  
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public String getSFileName() $]8
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{ d'Zqaaf k%  
return sFileName; '7oA< R  
} ,u/aT5\_  
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public void setSFileName(String value) Y*!qG  
{ yR4|S2D3xn  
sFileName = value; u?+Kkk
k  
} /r=tI)'$  
~{Mn{  
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public int getNSplitter() -Y='_4s  
{ Q_t`.
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return nSplitter; !tp1:'KG  
} v;0|U:`]  
5Lf{8UxI  
TYQwy*  
public void setNSplitter(int nCount) qkC/\![@  
{ VH[hsj  
nSplitter = nCount; Qm/u h  
} DoeiW=  
} RoyPrO [3  
W>O~-2  
39=1f6I1  
/* d$ ^ ,bL2p  
**Utility.java gmm|A9+tv  
*/ >Bgw}PI  
package NetFox; X@f "-\  
$ mI0Bk  
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public class Utility { |M+<m">E  
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public Utility() g]c6&Y,#  
{ VhNz8)  
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} TsGE cxIg  
z-b*D}&  
//线程睡眠 kP?KXT3y  
public static void sleep(int nSecond) et }T%~T  
{ [AW" D3  
try{ ]Ei0d8Uo  
Thread.sleep(nSecond); 'CN|'W)g7  
} *;fw%PW  
catch(Exception e) =|YxDas  
{ ;]pJj6J&v  
e.printStackTrace (); D`VM6/iQR  
} ph-ATJ"  
} ^Y iJV7  
%b"\bHH  
//日志 1[yq0^\]M[  
public static void log(String sMsg) ('hEr~&  
{ Ck!VV2U#  
System.err.println(sMsg); +*hm-lv?  
} :Cp'm'omb  
/=gOa\k|p  
2^l[(N  
public static void log(int sMsg) =hMY2D  
{ R<=zCE`:  
System.err.println(sMsg); ~>+]%FPv  
} LH@j8YB5u  
} Yx>"bv  
>`%'4<I  
2!$gyu6bpG  
/*
q@xBJ[IM  
**TestMethod.java HdPoO;  
*/ 0JJS2oY/  
package NetFox; lj?v4$  
;asP4R=  
QJ7L7S  
public class TestMethod { l!g]a2x*  
$.[#0lCI  
pe{;~-|6  
public TestMethod() y})70w@+_  
{ ///xx/weblogic60b2_win.exe g=$1cC+(  
try{ ''Cay0h  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5);  ,qYJioWX  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); [ U wi  
SiteFileFetch fileFetch = new SiteFileFetch(bean); R]i7 $}n  
fileFetch.start(); as>L[jyG/  
} C,.Ee3T  
catch(Exception e){e.printStackTrace ();} *Otg*,\  
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-P]sRl3O;  
} 2[r^M'J  
[Ts"OPb%~  
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public static void main(String[] args) U\sHx68  
{ = hN !;7G  
new TestMethod(); }ga@/>Sl&  
} S*,rGCt'T  
} w#g#8o>'  
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