http断点续传简单实现（java)

/* ~ oq.yn/1  
**SiteFileFetch.java E[zq<&P@  
*/ fk1d iB  
package NetFox; aCIz(3^  
import java.io.*; v^p* l0r6:  
import java.net.*; <pKOFN%
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public class SiteFileFetch extends Thread { Qz2jV
 
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SiteInfoBean siteInfoBean = null; //文件信息Bean 2VX9FDrnk  
long[] nStartPos; //开始位置 HB*BL+S06  
long[] nEndPos; //结束位置 'Ce?!UO  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 #}~?8/h!  
long nFileLength; //文件长度 0a@tPskV  
boolean bFirst = true; //是否第一次取文件  z.2UZ%:  
boolean bStop = false; //停止标志 rxJl;!7G  
File tmpFile; //文件下载的临时信息 S+mBVk"-~S  
DataOutputStream output; //输出到文件的输出流 I1dOMu9  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） g1y@z8Z{  
public SiteFileFetch(SiteInfoBean bean) throws IOException O ]-8 %  
{ K*1]P ar;  
siteInfoBean = bean; 4"iI3y~Gw  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); *r9D+}Y(4  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 86?~N  
if(tmpFile.exists ()) LtKR15h,  
{ a%6=sqxE  
bFirst = false; X2,v'`U5&  
read_nPos(); Y-+Kf5_[  
} VJCj=jX  
else 3G^A^]h  
{ i\.(6hf+  
nStartPos = new long[bean.getNSplitter()]; 8-kR {9r  
nEndPos = new long[bean.getNSplitter()]; $`vXI%|.  
} m@L>6;*  
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} 1sJz`+\  
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public void run() VtU2&  
{ ^AZv4H*~  
//获得文件长度 P-yVc2YH  
//分割文件 C+t
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//实例FileSplitterFetch d}Y#l}!E6  
//启动FileSplitterFetch线程 sE{5&aCSR  
//等待子线程返回 GH3RRzp r  
try{ Y[rCF=ZVH  
if(bFirst) od,,2pwK+  
{ U!BZsVx  
nFileLength = getFileSize(); ,LL
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if(nFileLength == -1) &Akw V-  
{ =W"T=p*j  
System.err.println("File Length is not known!"); !kh:zTP  
} <9$Pl%:  
else if(nFileLength == -2) +I*a=qjq  
{ oGbh*  
System.err.println("File is not access!"); "dYT>w  
} YETGq-  
else W!=ur,F+  
{ ).Iifu|
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for(int i=0;i<nStartPos.length;i++) %Br1b6 V  
{ {`>pigo  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ,#0#1k<Dm  
} #W_-S0>&  
for(int i=0;i<nEndPos.length-1;i++) dww4o~hO  
{ FS!vnl8`  
nEndPos = nStartPos[i+1]; or7l}X  
} ew c:-2Y^  
nEndPos[nEndPos.length-1] = nFileLength; oJE<}~_k  
} N>sHT =_  
} :Z83*SPc  
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//启动子线程 D&],.N  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; c% ?@3d  
for(int i=0;i<nStartPos.length;i++) P/k#([:2  
{ G \$x.  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), =4!m]*y  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ^0
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nStartPos,nEndPos,i); M3JV^{O/DV  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); `bLJwJ7  
fileSplitterFetch.start(); 9"M-nH*<  
} -&%! 4(Je  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), +lf`Dd3  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); wjOJn]  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", (&_~eYZU  
nEndPos = " + nFileLength); e%7#e%1s  
// fileSplitterFetch[nPos.length-1].start(); |a'$v4dCF  
$HRl:KDdP~  
(~"#=fs.L  
//等待子线程结束 :#N]s  
//int count = 0; T/hz23nH  
//是否结束while循环 #.,LWL]  
boolean breakWhile = false; $L]M3$\9  
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while(!bStop) }`76yH
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{ Wk }}f|O0  
write_nPos(); $g,v]MW  
Utility.sleep(500); ZlcEeG  
breakWhile = true; c;#gvE  
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for(int i=0;i<nStartPos.length;i++) 2';{o=TXV  
{ .`&k`  
if(!fileSplitterFetch.bDownOver) 7WNUHLEt  
{ Jr(Z Ym'  
breakWhile = false; @v\8+0  
break; ArT@BqWd  
} .rlLt5b%  
} a`U/|[JM  
if(breakWhile) }/L#<n`Z  
break; *A0d0M]cg  
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//count++; t7e7q"+/  
//if(count>4) ow'CwOj$  
// siteStop(); %w/vKB"nO  
} b<E78B+Aax  
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System.err.println("文件下载结束！"); nHLMF7\  
} xd
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catch(Exception e){e.printStackTrace ();} =W gzj|Kr  
} emT/H95|,  
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//获得文件长度 owA.P-4  
public long getFileSize() Y44[2 :m
 
{ jZe/h#J)[  
int nFileLength = -1; @F|pKf:M+  
try{ -AB0uMot  
URL url = new URL(siteInfoBean.getSSiteURL()); ''p
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); aZq7(pen  
httpConnection.setRequestProperty("User-Agent","NetFox"); q{L-(!uz7_  
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int responseCode=httpConnection.getResponseCode(); F&7^M0x\ O  
if(responseCode>=400) !2.eJ)G  
{ n3\~H9  
processErrorCode(responseCode); q{xF7}i  
return -2; //-2 represent access is error JL7;l0#  
} Y/L*0M.<  
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String sHeader; +u`4@~D#  
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for(int i=1;;i++) Jpn= ^f[rm  
{ Z~;rp`P  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); K[Vj+qdyl  
//Utility.log(in.readLine()); R I:kp.V  
sHeader=httpConnection.getHeaderFieldKey(i); NE|Q0g  
if(sHeader!=null) `r %lB  
{ P!XO8X 1F  
if(sHeader.equals("Content-Length")) +$#h6V  
{ Q5Epq sKyC  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); -\25&m!+  
break; sDBwD%s
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} $gCN[%+j  
} *bzqH2h8  
else KC8  
break; Io{BO.K*Y  
}
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} PE?ICou  
catch(IOException e){e.printStackTrace ();} _]L]_Bh  
catch(Exception e){e.printStackTrace ();} Zlrbd  
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Utility.log(nFileLength); 3XDuo|(  
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return nFileLength; ;"8BbF.  
} tHr4/  
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D/
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//保存下载信息（文件指针位置） y=AF EP  
private void write_nPos() Th$xk9TK^@  
{ rkz84wDx  
try{ !iK{q0  
output = new DataOutputStream(new FileOutputStream(tmpFile)); CXTtN9N9  
output.writeInt(nStartPos.length); p!\GJ a",  
for(int i=0;i<nStartPos.length;i++) `r0lu_.$]4  
{ G7r.Jm^q  
// output.writeLong(nPos); g`)0 wP  
output.writeLong(fileSplitterFetch.nStartPos); lWBewnLKE  
output.writeLong(fileSplitterFetch.nEndPos);
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} 4P#4RB  
output.close(); 3jHE,5m  
} 7W>(T8K X\  
catch(IOException e){e.printStackTrace ();} Q
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catch(Exception e){e.printStackTrace ();} |<uBJ-5  
} g@Rs.Zq  
j' b0sve|?  
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//读取保存的下载信息（文件指针位置） moZeP#Q%  
private void read_nPos() pdjRakN  
{ Y&bO[(>1  
try{ (B03f$8}*_  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); E H|L1g  
int nCount = input.readInt(); s}bLA>~Ta  
nStartPos = new long[nCount]; 0IBQE  
nEndPos = new long[nCount]; UUF]45t>  
for(int i=0;i<nStartPos.length;i++)  SWyJ`  
{ e7plL^^`  
nStartPos = input.readLong(); pwV~[+SS_  
nEndPos = input.readLong(); =,X*40=  
} MooxT7  
input.close(); D$E#:[  
} hDc
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catch(IOException e){e.printStackTrace ();} 7\gu
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catch(Exception e){e.printStackTrace ();} $f>(T
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} q(Ow:3&  
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private void processErrorCode(int nErrorCode) OjrZ6  
{ i`?yi-R&  
System.err.println("Error Code : " + nErrorCode); \[%_ :9eq  
} 
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//停止文件下载 PH'n`
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public void siteStop() XV,ce~ro[  
{ IYa(B+nB)  
bStop = true; e*d lGK3l  
for(int i=0;i<nStartPos.length;i++) dJlK'zK  
fileSplitterFetch.splitterStop(); U8@P/Z9  
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} 9#kk5)J  
} O'QnfpQ*9  
//负责部分文件的抓取 ,fo7. h4{  
**FileSplitterFetch.java PF+Or  
*/ 9D;
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package NetFox; [w)KNl  
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import java.io.*; Dw y|mxlFn  
import java.net.*; - b`
  
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public class FileSplitterFetch extends Thread { GH&5m44  
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String sURL; //File URL JOs kf(  
long nStartPos; //File Snippet Start Position {wO.nOB  
long nEndPos; //File Snippet End Position rd"!&i  
int nThreadID; //Thread's ID jHObWUX  
boolean bDownOver = false; //Downing is over 2EO9IxIf  
boolean bStop = false; //Stop identical ce719n$   
FileAccessI fileAccessI = null; //File Access interface ZZc^~  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException j)Z0K
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{ \gv-2.,  
this.sURL = sURL; )Lk2tvr  
this.nStartPos = nStart; Bx.hFEL  
this.nEndPos = nEnd; dKL9}:oUa  
nThreadID = id; z80*Ylx  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 /q/^B>]  
} Oi{J}2U  
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public void run() $U(D*0+o/  
{ mxe\+j#  
while(nStartPos < nEndPos && !bStop) <TSps!(#  
{ !>&G+R+k  
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a FWTm,)  
try{ OC\cN%qlw  
URL url = new URL(sURL); ^;?
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); SCfk!GBVD  
httpConnection.setRequestProperty("User-Agent","NetFox"); ETR7%0$r  
String sProperty = "bytes="+nStartPos+"-"; S(rnVsW%Ki  
httpConnection.setRequestProperty("RANGE",sProperty); B}aW y&D  
Utility.log(sProperty); F)19cKx7  
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InputStream input = httpConnection.getInputStream(); auM1k]  
//logResponseHead(httpConnection); 7 Rc/<,X  
?q0a^c?A^  
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byte[] b = new byte[1024]; M
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int nRead; ZvK3Su)f1  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) @(."[O:  
{ -W:@3\{  
nStartPos += fileAccessI.write(b,0,nRead); 5r;)Ppo  
//if(nThreadID == 1) dkg+_V!  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); E^~ {thf  
} &]anRT#  
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Utility.log("Thread " + nThreadID + " is over!"); ?wjk=h
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bDownOver = true; 0\eSiXs  
//nPos = fileAccessI.write (b,0,nRead); Cq-99@&;  
} Eok8+7g0&  
catch(Exception e){e.printStackTrace ();} z_8Bl2tl  
} =CL,+  
} psS
^  
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//打印回应的头信息 r8A'8g4cM  
public void logResponseHead(HttpURLConnection con) FtWO[*#  
{ rAgpcp}  
for(int i=1;;i++) d Z+7S`{  
{ DnN+W  
String header=con.getHeaderFieldKey(i); "k),;1  
if(header!=null) j}8^gz]  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); }Fu2
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Utility.log(header+" : "+con.getHeaderField(header)); t=[/L]!  
else QEmktc1 7  
break; E#kH>q@K`$  
} 5F:\U  
} U)z1RHP|z  
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public void splitterStop() s GrI%3[e"  
{ %H}M[_f  
bStop = true; 2m72PU<.  
} dE(d'*+a  
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} g](&H$g  
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/* *LvdrPxU=  
**FileAccess.java UG6\OgkL+  
*//文件访问(定位，写) +ERuZc$3,  
package NetFox; paxZlA o  
import java.io.*; eE{ 2{C  
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public class FileAccessI implements Serializable{ sr:hRQ27  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 q?f-h<yRQ  
RandomAccessFile oSavedFile; -BsZw. 7P  
long nPos; Mv7tK l  
 ~"h V-3U  
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public FileAccessI() throws IOException 7[}WvfN8#  
{ ^brh\M,:@  
this("",0); oK&G  
} a$LoQ<f_  
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public FileAccessI(String sName,long nPos) throws IOException 8JO(P0aT  
{ n|PW^kOE/  
oSavedFile = new RandomAccessFile(sName,"rw"); 9|9/8a6A  
this.nPos = nPos; YDEb MEMd/  
oSavedFile.seek(nPos); li~=85 J  
} [,|4%Y  
.O PBET(gv  
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public synchronized int write(byte[] b,int nStart,int nLen) L-e6
^
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{ vNU[K%U  
int n = -1; fqol-{F.V  
try{ D6EqJ,~  
oSavedFile.write(b,nStart,nLen); AgdU@&^  
n = nLen; ulk yP  
} o* QZf*M  
catch(IOException e) P{8<U8E  
{ a$Ghb]  
e.printStackTrace (); M!\6Fl{ b  
} J!zL)u|  
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return n; 'gk^NAG2^E  
} N&u(9Fxn  
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} 0f
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D\sh +}"  
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/* mpl^LF[  
**SiteInfoBean.java `P;uPQDzZ3  
*/ [wUJ~~2#  
package NetFox; mS]soYTQ  
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public class SiteInfoBean { 4Y
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r
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private String sSiteURL; //Site's URL gac/%_-HH7  
private String sFilePath; //Saved File's Path 0-U%R)Q  
private String sFileName; //Saved File's Name TI3@/SB>  
private int nSplitter; //Count of Splited Downloading File Q!W+vh  
=5h,ZB2A  
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public SiteInfoBean() hQDl&A  
{//nSplitter的缺省值为5 R"QWap}  
//default value of nSplitter is 5 f<@`{oP@  
this("","","",5); $`/F5R!  
} 6^nxw>-  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) cA+O]",}  
{ NW
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sSiteURL= sURL; ?yvjX90  
sFilePath = sPath; cX48?srG  
sFileName = sName; Z`@< O%  
this.nSplitter = nSpiltter; Pv3 e*I(
(  
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} 4)d#dy::\  
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public String getSSiteURL() TfFH!1^+  
{ %>:d5"&Lbs  
return sSiteURL; lQer|?#  
} ,wk %)^  
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public void setSSiteURL(String value) :FI4GR*?  
{ (t-JGye>  
sSiteURL = value; mRY~)<!4&  
} n
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+~M`rR*  
|'12Kv]#Xa  
public String getSFilePath() j;i7.B"[  
{ V?Ye^-29  
return sFilePath; K#'{Ko  
} a(eUdGJ  
{;
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 =uIeur  
public void setSFilePath(String value) Pb@9<NXm'  
{ KEvT."t  
sFilePath = value; \g\,  
} 8@4)p.{5I  
*'ex>4^  
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public String getSFileName() +J%9%DqF  
{ 'B$qq[l]S  
return sFileName; E.OL_\  
} n/-d56  
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5y|/}D>  
public void setSFileName(String value) a`uHkRX )U  
{ {t<U:*n2  
sFileName = value; `$N AK  
} L\H,cimN  
+;wu_CQu  
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public int getNSplitter() <YBA 7i  
{ *ZA.O  
return nSplitter; bcZ s+FOPd  
} A{b?ZT~2]  
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[1gWc`#  
public void setNSplitter(int nCount) xk8P4`;d$  
{ &+V|Ldh  
nSplitter = nCount; /I3>u  
} Q[N6#C:(4  
} WD,iY_'7u^  
<xQHb^:  
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/* #97w6,P+  
**Utility.java Upkw.`D`  
*/ 6@@J>S>  
package NetFox; H{3A6fb<  
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public class Utility { F82_#|kpS  
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public Utility() s'|^6/  
{ AHre#$`97  
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7-hSso.'  
} S+EC!;@Xg  
-h<Rby  
//线程睡眠 SMdQ,n1]  
public static void sleep(int nSecond) amK.H"  
{ b:uMON,H  
try{ _A%8oYS  
Thread.sleep(nSecond); >O:j.(*!  
} @4N@cM0   
catch(Exception e) K)C9)J<  
{ %l7|+%M.{  
e.printStackTrace (); n/fMq,<8  
} %2)'dtPD~  
} lC ^NhQi  
*?Sp9PixP  
//日志 jI(}CT`g  
public static void log(String sMsg) y84=Q  
{ )q48cQ  
System.err.println(sMsg); ,U#$Qb 12  
} w1+xl
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r-$SF5uv  
|?Z;tAF!  
public static void log(int sMsg) `|i[*+WC  
{ GX+oA]  
System.err.println(sMsg); {$ghf"  
}
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} 7VdG6`TDR  
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(Wu_RXfCw_  
/* cDS6RO?  
**TestMethod.java W/m,qilQI  
*/ KXP^F6@l  
package NetFox; +)4_1i4"x  
jHj*S9:`  
od\Q<Jm}  
public class TestMethod { "&ElKy 7j  
vq~btc.p{&  
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public TestMethod() hi I`ot  
{ ///xx/weblogic60b2_win.exe ?-P]m&nh|  
try{ 7Xu.z9y  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); )r#^{{6[v  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ~97T0{E3  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 1}{bHj  
fileFetch.start(); ^y,%Tv>  
} i-'rS/R  
catch(Exception e){e.printStackTrace ();} `)[bu  
n 4:Yc@,  
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} IG1+_-H:  
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public static void main(String[] args) ugtb`d{ Sl  
{ )/u?_)b4"  
new TestMethod(); _-^Lr /`G!  
} $~<);dYu0  
} at@B>Rb  
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