http断点续传简单实现（java)

/* =C.WM*='  
**SiteFileFetch.java SR\F2@u  
*/ P",E/beV  
package NetFox; 2DbM48\E  
import java.io.*; +4%:q~C  
import java.net.*; vs~lyM/  
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public class SiteFileFetch extends Thread { Co#_Cyxg=9  
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SiteInfoBean siteInfoBean = null; //文件信息Bean nmrYBw>  
long[] nStartPos; //开始位置 Bpw<{U  
long[] nEndPos; //结束位置 ,"W.A  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 X}gnO83  
long nFileLength; //文件长度 Du2v,n5@  
boolean bFirst = true; //是否第一次取文件 !HP/`R  
boolean bStop = false; //停止标志 vAMr&[  
File tmpFile; //文件下载的临时信息 jL[ hB  
DataOutputStream output; //输出到文件的输出流 Y2,\WKa  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） SMdkD]{g  
public SiteFileFetch(SiteInfoBean bean) throws IOException hMiuv_EO!  
{ B=`"!?we  
siteInfoBean = bean; 9&`ejeD  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); .wfN.Z  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Z*r
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if(tmpFile.exists ()) d4#Ra%  
{ d@72z r  
bFirst = false; .4NQ2k1io  
read_nPos(); op%?V:  
} .5~W3v <  
else Z/ypWoV(  
{ @.fyOyOC  
nStartPos = new long[bean.getNSplitter()]; XiB]I5(hcc  
nEndPos = new long[bean.getNSplitter()]; *t+E8)qL  
} CxOBH89(  
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} ~t~5ctJ@  
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public void run() E0i_sB~T  
{ CF`fn6  
//获得文件长度 tyLR_@i%%  
//分割文件 MXxE)"G*a  
//实例FileSplitterFetch P00pSRQHD  
//启动FileSplitterFetch线程 +i[w& P  
//等待子线程返回 Xkv+"F=-  
try{ F& 'HZX  
if(bFirst) ,T|%vqbmw  
{ ymsqJ   
nFileLength = getFileSize(); }bs2Rxkh  
if(nFileLength == -1) a;A&>Ei}  
{ D?w-uR%Y  
System.err.println("File Length is not known!"); =/Dp*  
} !I? J^0T  
else if(nFileLength == -2) o\luE{H .?  
{ (qP !x 2j  
System.err.println("File is not access!"); 0P_Y6w+  
} nAp7X-t  
else 4D/mm(2d$  
{ 2ju1<t,8)  
for(int i=0;i<nStartPos.length;i++) Lz VvUVk  
{ RhJL`>W`  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); "F+Wo&  
} Yb|zE   
for(int i=0;i<nEndPos.length-1;i++) 2Z-BZuK6p  
{ 3o'SY@'W  
nEndPos = nStartPos[i+1]; CDcs~PR@B  
} h,@x5q>g  
nEndPos[nEndPos.length-1] = nFileLength; ~%Ws"1  
} uxto:6),P<  
} >Q~"/-bN)  
L?^C\g6u]  
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//启动子线程 ] 05Q4  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; BX),
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for(int i=0;i<nStartPos.length;i++) tc{23Rf%  
{ b'N"?W^YQ  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), _OF8D
  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 2#Au6BvX  
nStartPos,nEndPos,i); "gCSbMq(Vq  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); B(MO!GNg=  
fileSplitterFetch.start(); nDvny0^a  
} ]sjOn?YA+  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 2="C6 7TK  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); OD"eB?  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", tE{7S/?h  
nEndPos = " + nFileLength); KG#|Cq  
// fileSplitterFetch[nPos.length-1].start(); iR#jBqXD  
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?.A6HrAPB  
//等待子线程结束 Q9[dUdQm  
//int count = 0; utwh"E&W  
//是否结束while循环 ^;YD3EZw  
boolean breakWhile = false; i[ BR"(  
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while(!bStop) nm'm*sU\  
{ r _r$nl  
write_nPos(); nX Qz  
Utility.sleep(500); ej<z]{`05  
breakWhile = true; ,ASY &J5)7  
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for(int i=0;i<nStartPos.length;i++) ]dDyz[NuvD  
{ ,)L.^<  
if(!fileSplitterFetch.bDownOver) CWkm\=  
{
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breakWhile = false; HIhoYSwB  
break; >[xQUf,p  
} Ro:-u7q  
} S0=BfkHi.  
if(breakWhile) XB;;
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break; Zt` ,DM  
xs &vgel>  
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//count++; :OI!YR%"  
//if(count>4) v2@M,xbxF:  
// siteStop(); Fr%KO)s2  
} udc9$uO  
+[2lS54"W4  
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System.err.println("文件下载结束！"); u gfV'  
} 5o~Z>  
catch(Exception e){e.printStackTrace ();} dbZPt~S'$  
} K0I-7/L  
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//获得文件长度 3!$rp- !<)  
public long getFileSize() 5WZLB =  
{ 9DtSYd/  
int nFileLength = -1; E$G"R=  
try{ G>_ZUHdI  
URL url = new URL(siteInfoBean.getSSiteURL()); &P{%C5?{  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); nj9hRiLn  
httpConnection.setRequestProperty("User-Agent","NetFox"); {{DW P-v4  
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int responseCode=httpConnection.getResponseCode(); r?V|9B`$p  
if(responseCode>=400) mU&J,C  
{ ;8b f5  
processErrorCode(responseCode); Y2$%%@  
return -2; //-2 represent access is error  b
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} YT:5J%"  
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String sHeader; vOP[ND=T  
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for(int i=1;;i++) =q"3a9pb7  
{ Ahebr{u  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); uC;@Yi8  
//Utility.log(in.readLine()); ss2:8up 99  
sHeader=httpConnection.getHeaderFieldKey(i); 6% ,Q  
if(sHeader!=null) Y.C*|p#  
{ QnGJ4F
  
if(sHeader.equals("Content-Length")) }M~AkJL  
{ (?3(=+t  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); dvj`%?=  
break; ,,iQG' *  
} "M*\,IH  
} '/p5tw8  
else I%s/h4x^B[  
break; QTyl=z7  
} $ `ho+  
} #e0+;kBh  
catch(IOException e){e.printStackTrace ();} jf2E{48P  
catch(Exception e){e.printStackTrace ();} 3~S~)quwP  
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"
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Utility.log(nFileLength); 7vWB=r>5@  
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return nFileLength; (C:rH  
} ;}PL/L$L6;  
/;>EyWW  
 6$Dbeb  
//保存下载信息（文件指针位置）
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private void write_nPos() ~lL($rE  
{ %$}iM<  
try{ SVHtv0Nx  
output = new DataOutputStream(new FileOutputStream(tmpFile)); a&<<X:$Hy  
output.writeInt(nStartPos.length); s6 ^JgdW  
for(int i=0;i<nStartPos.length;i++) O|/tRkDMP{  
{ lDA%M3(p  
// output.writeLong(nPos); ~& l`"  
output.writeLong(fileSplitterFetch.nStartPos); 3A9|{Vaz+6  
output.writeLong(fileSplitterFetch.nEndPos); {!4%Z9G  
} aD:+,MZ  
output.close(); aqN.5'2\  
} 5Tu.2.)N  
catch(IOException e){e.printStackTrace ();} n#R!`*[  
catch(Exception e){e.printStackTrace ();} Ea !j-Lbo  
} Owr`ip\  
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=
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//读取保存的下载信息（文件指针位置） {J]|mxo  
private void read_nPos() ,s)H%  
{ ~E\CAZ  
try{ BOG )JaDW  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); x{- caOH  
int nCount = input.readInt(); +1y#=iM{  
nStartPos = new long[nCount]; *SW,pHYnLb  
nEndPos = new long[nCount]; @PI\.y_w  
for(int i=0;i<nStartPos.length;i++) F,bl>;{[{  
{ t>[r88v  
nStartPos = input.readLong(); h Na<LZ  
nEndPos = input.readLong(); wVVe L$28  
} AjS5  
input.close(); oMVwIdf  
} 4M]8po/;  
catch(IOException e){e.printStackTrace ();} )<|TEp4r-  
catch(Exception e){e.printStackTrace ();} Q
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} : ?V;  
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private void processErrorCode(int nErrorCode) Dn[
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{ p%s D>1k  
System.err.println("Error Code : " + nErrorCode); JjmL6(*ui  
} ymzm x$o=  
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//停止文件下载 zxh"@j$?  
public void siteStop() = `^jz}  
{ jmFN*VIL  
bStop = true; NR*SEbUU*  
for(int i=0;i<nStartPos.length;i++) >g[W@FhT'k  
fileSplitterFetch.splitterStop(); QJ>>&`{,  
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} :QVGY^c  
} --9mTqx  
//负责部分文件的抓取 qj1z>,\  
**FileSplitterFetch.java T)uw2  
*/ ]ok>PH]  
package NetFox; cC4T3]4l'  
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import java.io.*; !r
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import java.net.*; j#&  
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public class FileSplitterFetch extends Thread { .bE,Q9:  
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String sURL; //File URL ;i9CQ0e?  
long nStartPos; //File Snippet Start Position a3;.{6el)H  
long nEndPos; //File Snippet End Position $c}0L0  
int nThreadID; //Thread's ID }$-VI\96  
boolean bDownOver = false; //Downing is over a%dx\&K  
boolean bStop = false; //Stop identical pd#/;LT  
FileAccessI fileAccessI = null; //File Access interface Xo`1#6xsE  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 6"7qZ
q
 
{ +2SX4Kxu  
this.sURL = sURL; Iqsk\2W]a3  
this.nStartPos = nStart; `y`xk<q  
this.nEndPos = nEnd; L?0l1P  
nThreadID = id; F(<8:`N;G  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 \ax%I)3  
} }kj6hnQ  
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public void run() @m V C  
{ {rT`*P~  
while(nStartPos < nEndPos && !bStop) o!~
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{ to3J@:V8e  
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try{ ;
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URL url = new URL(sURL); ?_aR-[XRg  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); spJ(1F{|V  
httpConnection.setRequestProperty("User-Agent","NetFox"); I*}#nY0+  
String sProperty = "bytes="+nStartPos+"-"; Ct)MvZ  
httpConnection.setRequestProperty("RANGE",sProperty); sh ;uKzQ  
Utility.log(sProperty); Rs`a@Fn  
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InputStream input = httpConnection.getInputStream(); B5:g{,C  
//logResponseHead(httpConnection); F-^HN%  
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byte[] b = new byte[1024]; s{e(- 7'  
int nRead; Ug21d42Z4  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ^d80\PXz  
{ :eW~nI.Vc  
nStartPos += fileAccessI.write(b,0,nRead); P0xL
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//if(nThreadID == 1) !dY:S';~  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); bZ.N7X PH  
} u4@e=vWI  
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Utility.log("Thread " + nThreadID + " is over!"); xV#a(>-4  
bDownOver = true;
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//nPos = fileAccessI.write (b,0,nRead); Ax
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} GYC&P]  
catch(Exception e){e.printStackTrace ();} wkD:i2E7  
} (0W}e(D8  
} jJZsBOW[8  
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//打印回应的头信息 7Zt\G-QV  
public void logResponseHead(HttpURLConnection con) gvNZrp>e!  
{ -j_I_  
for(int i=1;;i++) :(>9u.>l?5  
{ |xZcT4  
String header=con.getHeaderFieldKey(i); mE`qvavP|/  
if(header!=null) >&QH{!(  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); {X<4wxeTo  
Utility.log(header+" : "+con.getHeaderField(header)); xn@0pL3B~  
else *ldMr{s<R  
break; U5!f++  
} q9Sz7_K  
} -Zg @D(pF  
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public void splitterStop() 9
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{ lt6
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bStop = true; j yRSEk$  
} =nx:GT3&[  
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} +RV-VrV  
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/* N4mJU'_{  
**FileAccess.java +xf
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*//文件访问(定位，写) +'/}[1q1/T  
package NetFox; (\t_Hs::a  
import java.io.*; ZuvPDW%  
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public class FileAccessI implements Serializable{ VS|("**  
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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 UIOEkQ\Wl  
RandomAccessFile oSavedFile; Z.':&7Y  
long nPos; ggI=I<7M  
s)YP%vn#  
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public FileAccessI() throws IOException u:$x6/t  
{ j-YJ."  
this("",0); 96pk[5lj{?  
}
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public FileAccessI(String sName,long nPos) throws IOException wD],{y  
{ nS+FX&_  
oSavedFile = new RandomAccessFile(sName,"rw"); *Z`XG_s5  
this.nPos = nPos; Ah>gC!F^  
oSavedFile.seek(nPos); o}
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} Sf&?3a+f  
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public synchronized int write(byte[] b,int nStart,int nLen) a3UPbl3^  
{ /Pn.)Lxf
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int n = -1; {(Og/
[  
try{ *SkiFEoD  
oSavedFile.write(b,nStart,nLen); j\'+wVyo  
n = nLen; px|>
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} 1V
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catch(IOException e) oY%"2PW1B  
{ X#DL/#z k  
e.printStackTrace (); ')5L_$  
} J4G> E.8  
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return n; Kr/h`RM  
} qA/#IUi)1  
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} Jf?S9r5Q  
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/* %e Sm&`  
**SiteInfoBean.java y98JiNq  
*/ \ I^nx+l  
package NetFox; W""*hJ  
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public class SiteInfoBean { NTm<6Is`  
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private String sSiteURL; //Site's URL | "Jx  
private String sFilePath; //Saved File's Path j?\$G.Y  
private String sFileName; //Saved File's Name >'aG/(  
private int nSplitter; //Count of Splited Downloading File d$fvg8^  
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7-".!M  
public SiteInfoBean() 6[*;M  
{//nSplitter的缺省值为5 4[TS4p  
//default value of nSplitter is 5
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this("","","",5); djsz!$  
} K/vxzHSl  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) m7r j>X Y  
{ W?qpnPW  
sSiteURL= sURL; uw
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sFilePath = sPath; VY/|WD~"CW  
sFileName = sName; j-J(C[[9  
this.nSplitter = nSpiltter; 5^i.;>(b  
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} nW|'l^&  
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public String getSSiteURL() I %|@3=Yc  
{ %cH8
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return sSiteURL; |XKOXa3.  
} ^IX%dzM  
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public void setSSiteURL(String value) oL<BLr9>  
{
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sSiteURL = value; "7=
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} ;asm 0H(  
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public String getSFilePath() X=v~^8M7%  
{ 5>k>L*5J  
return sFilePath; wgY6D!Y   
} }m6f^fs}  
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[IiwNqZ[~  
public void setSFilePath(String value) ,YjxCp3  
{ 9s!
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sFilePath = value; /~40rXH2C
 
} Hm>-LOCcl  
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JOBz{;:R{  
public String getSFileName() 8r,9OM  
{ m_a^RB(  
return sFileName; -=>sTMWpr  
} Hx$.9'Oq\Q  
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public void setSFileName(String value) D=$4/D:;  
{ }@d>,1DU  
sFileName = value; r0>q%eM8  
} N83!C=X'  
l+%Fl=Q2em  
SOVjEo4'3  
public int getNSplitter() >Q; g0\I_  
{ O?CdAnhQc`  
return nSplitter; :^n*V6.4  
} YWEYHr;%^?  
6`acg'sk>  
:-z&Y492  
public void setNSplitter(int nCount) K[kds`  
{ H4t)+(:D'  
nSplitter = nCount; Zr=ib  
} 70_}S*T  
} ^f9>l;Lb  
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/* >-b&v$  
**Utility.java *-0>3  
*/ 0; 7#ji  
package NetFox; `|nH1sHFq  
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public class Utility { B`i$Wt<7  
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public Utility() 69>/@<   
{ ymYBm:"  
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} 0Z"s_r}h  
jgG$'|s}  
//线程睡眠 6D|p Qs  
public static void sleep(int nSecond) /hL\,x2  
{ g0PT8]8  
try{ E, GN|l  
Thread.sleep(nSecond); Qlw>+y-i  
} 9TC) w|
 
catch(Exception e) 58::h.:  
{ ~(P&g7u  
e.printStackTrace (); 09'oz*v{#  
} uQnT[\k?  
} H9U.lb  
{Ur7#h5  
//日志 @Gt`Ds9=  
public static void log(String sMsg) V@[rf<,  
{ m^<p8KZ  
System.err.println(sMsg); |jsb@  
} uAUp5XP|Z  
S`0NPGn;@[  
dN< ,%}R  
public static void log(int sMsg) $E\^v^LW  
{ >TY6O.]  
System.err.println(sMsg); R::zuv  
} \8e2?(@"k  
} L_~8"I_  
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/* Lkn4<'un  
**TestMethod.java -jB3L:  
*/ TkRm
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package NetFox; ziiwxx_  
"oR@JbdX  
\9`#]#1bx5  
public class TestMethod { -U>y  
7/aOsW"6  
1yMr~Fo  
public TestMethod() Or8kp/d  
{ ///xx/weblogic60b2_win.exe b5<okICD  
try{ 22&;jpL'?  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); /`3#4=5-  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); FQk!d$BG  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ?{6s58Q{  
fileFetch.start(); I`T1
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} BJk Z2=  
catch(Exception e){e.printStackTrace ();} H}/05e  
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uR$i48}  
} 1y(UgEg   
\F{:5,Du)  
:5b0np!  
public static void main(String[] args) ~E)fpGJ  
{ WF[bO7:  
new TestMethod(); F'FP0t!S
 
} O6X"RsI}  
} 2:SO_O4C  
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