http断点续传简单实现（java)

/* ("UcjB^62  
**SiteFileFetch.java B-`d7c5  
*/ E5"%-fAJ  
package NetFox; /Zw^EM6c  
import java.io.*; 3'WJx=0?  
import java.net.*; l;
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public class SiteFileFetch extends Thread { .}gGtH,b3  
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SiteInfoBean siteInfoBean = null; //文件信息Bean v-u53Fy  
long[] nStartPos; //开始位置
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long[] nEndPos; //结束位置 EJ7}h?a]U_  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ^eke,,~  
long nFileLength; //文件长度 SQ7Ws u>T@  
boolean bFirst = true; //是否第一次取文件 7i?"akr4  
boolean bStop = false; //停止标志 M qq/k J  
File tmpFile; //文件下载的临时信息 ~bU!4P}4j  
DataOutputStream output; //输出到文件的输出流 csP 5R3  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 0OLE/T<Xv  
public SiteFileFetch(SiteInfoBean bean) throws IOException xu9K\/{7  
{ :tclYX  
siteInfoBean = bean; 5.!iVyN  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); `7<4]#b^o  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); i
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if(tmpFile.exists ()) 4DaLt&1  
{ n$B SO  
bFirst = false; /c3A>  
read_nPos(); ;]AJ_h(<`  
} V'TBt=!=]  
else (ZR+(+i,  
{ Do-~-d4  
nStartPos = new long[bean.getNSplitter()]; K(P2
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nEndPos = new long[bean.getNSplitter()]; fWo}gH~  
} #~]S  
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{&Kck>C'  
} ?K9&ye_rgw  
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public void run() HD^Ou5YB  
{ f5p>oXo4b  
//获得文件长度 Pi|WOE2  
//分割文件 # +OEO  
//实例FileSplitterFetch Q/'jwyj_  
//启动FileSplitterFetch线程 K,f*}1$qM  
//等待子线程返回 ;tK%Q~To  
try{ tQz=_;jy  
if(bFirst) R5PXX&Q  
{ t[$C r;  
nFileLength = getFileSize(); t5
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if(nFileLength == -1) n.+%eYM<  
{ 0X6|pC~  
System.err.println("File Length is not known!"); v%gkQa
 
} 9K~0:c  
else if(nFileLength == -2) h/`]=kCl  
{ xZ'-G6O "~  
System.err.println("File is not access!"); y(gL.08<  
} fyYH
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else ~*aPeJ  
{ !EO
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for(int i=0;i<nStartPos.length;i++) f|U;4{k  
{ s|*0cK!K^  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); L9(mY `d>"  
} cE(P^;7D  
for(int i=0;i<nEndPos.length-1;i++) 7wKN  
{ FKhmg&+>  
nEndPos = nStartPos[i+1]; !h\.w9o[  
} b EB3#uc  
nEndPos[nEndPos.length-1] = nFileLength; ?\|QDJXY  
} ZBw]H'sT  
} ?#N: a  
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//启动子线程 aMaICM  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; @E Srj[  
for(int i=0;i<nStartPos.length;i++) lG[@s 'j  
{ =j,2  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), -G\svwv@)  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), l|WdJn o  
nStartPos,nEndPos,i); m/ D~D~  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); <%d/"XNg[D  
fileSplitterFetch.start(); |"}F cS y  
} Vf28R,~m  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), MR")  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); rw:z|-r  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", N{/):O  
nEndPos = " + nFileLength); zVEG) Hr  
// fileSplitterFetch[nPos.length-1].start(); T'VZ=l[  
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=rL%P~0wq  
//等待子线程结束 0v7#vZ  
//int count = 0; `<Ry_}V  
//是否结束while循环 EJAk'L+nuH  
boolean breakWhile = false; ANIx0*Yl(  
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while(!bStop) Oy(fh%k#  
{ Jd]
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write_nPos(); pl#2JA8  
Utility.sleep(500); tVI6GXH  
breakWhile = true; 244[a] %&;  
> nHaMj  
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for(int i=0;i<nStartPos.length;i++) &TgS$
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{ E;`@S  
if(!fileSplitterFetch.bDownOver) exW|c~|m{A  
{ =()Vrk|uK  
breakWhile = false; D*T*of G  
break; Ms4~P6;%  
} gc<w nm|  
} B3AWJ1o  
if(breakWhile) {J&[JA\  
break; ;?{[vLHDL  
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//count++; T`ofj7$:  
//if(count>4) ww
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// siteStop(); j\hI, mc  
} l& A8P  
nYFM^56>_  
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System.err.println("文件下载结束！"); \ 8v^ hb  
} $U/|+*  
catch(Exception e){e.printStackTrace ();} [SKN}:D  
} 0Dt-!Q7  
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*F:)S"3_~e  
//获得文件长度 gT-"=AsxZQ  
public long getFileSize() \iP=V3  
{ VTUY#+3  
int nFileLength = -1; 0<3->uK  
try{ ID_#a9N  
URL url = new URL(siteInfoBean.getSSiteURL()); 4UxxmREx;  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); l('@~-Zy  
httpConnection.setRequestProperty("User-Agent","NetFox"); c1Rn1M,2k  
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int responseCode=httpConnection.getResponseCode(); R:+cumHr  
if(responseCode>=400) s~p(59  
{ ;_~9".'<d  
processErrorCode(responseCode); >0X_UDAWz  
return -2; //-2 represent access is error iNCT(N~.  
} f>CJ1;][{  
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String sHeader; 5+DId7d'n  
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u
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for(int i=1;;i++) /R(]hmW  
{ 0h-'TJg*sk  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); :L+%5Jq  
//Utility.log(in.readLine()); Ga]\~31NE  
sHeader=httpConnection.getHeaderFieldKey(i); GBY-WN4sc[  
if(sHeader!=null) \[9^,QP  
{ _LSp \{Z  
if(sHeader.equals("Content-Length")) goqm6
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{ BjyV&1tRV!  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); c5em*qCw$  
break; dW5@Z-9  
} j 06mky  
} Y*QoD9<T?;  
else R>D
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break; kXroFLrY  
} fW w+'xF!  
} Gk']Ma2J}  
catch(IOException e){e.printStackTrace ();} ;#?G2AAv  
catch(Exception e){e.printStackTrace ();} =5;tB  
: i{tqY%  
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Utility.log(nFileLength); X> T_Xc  
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return nFileLength; ;(-Wc9=  
} u[
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]++,7Z\AU  
//保存下载信息（文件指针位置） zRMz8IC.  
private void write_nPos() z"c,TlVN3  
{ 6rMXv0)  
try{ D>-srzw  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ZmDM
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output.writeInt(nStartPos.length); ,MjlA{0  
for(int i=0;i<nStartPos.length;i++) %Jji<M]  
{ DkEf;P  
// output.writeLong(nPos); &. MUSqo9  
output.writeLong(fileSplitterFetch.nStartPos); " ?Ux\)*  
output.writeLong(fileSplitterFetch.nEndPos); #p<(2wN  
} Iw4[D#o  
output.close(); VXnWY8\  
} 5\Rg%Ezl  
catch(IOException e){e.printStackTrace ();} pr[V*C/  
catch(Exception e){e.printStackTrace ();} ?3%r:
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} Nwo*tb:  
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//读取保存的下载信息（文件指针位置） ? q_%  
private void read_nPos() A%cJ5dF8~  
{ j 8)*'T  
try{ ,e^~(I
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DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); rJ{k1H>  
int nCount = input.readInt(); Z,DSTP\|  
nStartPos = new long[nCount]; R=3|(R+kA  
nEndPos = new long[nCount]; +Ks3  
for(int i=0;i<nStartPos.length;i++) "rrw~  
{ {PkR6.XhR  
nStartPos = input.readLong(); q|}O-A*wa  
nEndPos = input.readLong(); f
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} /:v}Ni"6nF  
input.close(); `-.6;T}2U  
} D_?dy4\  
catch(IOException e){e.printStackTrace ();} K 6yD64  
catch(Exception e){e.printStackTrace ();} yIC C8M  
} I Z|EPzS  
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private void processErrorCode(int nErrorCode) @?jbah
#  
{ ;Y,zlq2  
System.err.println("Error Code : " + nErrorCode); e8E'X  
} CkRilS<  
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//停止文件下载 (f2r4Io|}  
public void siteStop() _F(Np\%_  
{ ^E_chx-e}  
bStop = true; $o.;}  
for(int i=0;i<nStartPos.length;i++) T[I7.8g  
fileSplitterFetch.splitterStop(); bXeJk]#y  
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} dV{mmHL  
} H& $M/`  
//负责部分文件的抓取 6HPuCP  
**FileSplitterFetch.java *+k yuY J  
*/ OrF.wcg  
package NetFox; jZQ{XMF  
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import java.io.*; 1>/ iYf  
import java.net.*; v$xurj:v#i  
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public class FileSplitterFetch extends Thread { YhzDw8f  
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String sURL; //File URL iJeodfC  
long nStartPos; //File Snippet Start Position s)?GscPG!  
long nEndPos; //File Snippet End Position }]M'f:%b  
int nThreadID; //Thread's ID \=P(?!v  
boolean bDownOver = false; //Downing is over %O!TS_~9  
boolean bStop = false; //Stop identical kT]jJbb"  
FileAccessI fileAccessI = null; //File Access interface ]0O3kiVQ  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 0176  
{ @FZ_[CYg  
this.sURL = sURL; @LFB}B  
this.nStartPos = nStart; t&p I  
this.nEndPos = nEnd; R)4,f~@"  
nThreadID = id; >Q'*~S@v3  
fileAccessI = new FileAccessI(sName,nStartPos);//定位
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} *VHWvj  
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public void run() sIbPMu`&U  
{ O)DAYBv^  
while(nStartPos < nEndPos && !bStop) Wsp c;]&  
{ ;" D~F  
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try{ :yE0DS<_  
URL url = new URL(sURL); &*E! %57  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); L7nG5i  
httpConnection.setRequestProperty("User-Agent","NetFox"); u\MxQIo'u  
String sProperty = "bytes="+nStartPos+"-"; '@ p464  
httpConnection.setRequestProperty("RANGE",sProperty); ho)JY $#6  
Utility.log(sProperty); }I MV@z B  
9~$E+m(  
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InputStream input = httpConnection.getInputStream(); H|7XfM  
//logResponseHead(httpConnection); azNv(|eeJL  
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byte[] b = new byte[1024]; l^KCsea#  
int nRead; j6};K ~N`  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 4"3.7.<Q`  
{ }D?qj3?bj  
nStartPos += fileAccessI.write(b,0,nRead); b
#"&]s-  
//if(nThreadID == 1) S>p0{:zM  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); s|:1z"q  
} uL@%M8n  
+Wgfxk'{  
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Utility.log("Thread " + nThreadID + " is over!"); OHW|?hI=[  
bDownOver = true; ]5K(}95&'  
//nPos = fileAccessI.write (b,0,nRead); <`G-_VI  
} +S+=lu _  
catch(Exception e){e.printStackTrace ();}
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} 3Agyp89}Q  
} %C@p4  
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//打印回应的头信息 G,c2?^
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public void logResponseHead(HttpURLConnection con) >4-9 @i0FV  
{ *0eV9!y  
for(int i=1;;i++) Zy.ls&<:  
{ a1Q%Gn@R  
String header=con.getHeaderFieldKey(i); sekei6#fi  
if(header!=null) $TS97'$  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); [Y?Y@x"MZ  
Utility.log(header+" : "+con.getHeaderField(header)); QSn18V>{  
else x]`@%8Sm  
break; @HSK[[?  
} ;<;~;od*/  
} '\+"3!$  
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public void splitterStop() Rj
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{ Yh;(puhyA  
bStop = true; Lz p}<B  
} tZVs0eVF<  
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} \x\N?$`ANc  
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/* O:a=94  
**FileAccess.java >dJ~  
*//文件访问(定位，写) Cz$q"U  
package NetFox; Lfdg5D5.P  
import java.io.*; ij~-  
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public class FileAccessI implements Serializable{ D`mr>-
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q,%Fvcmx+e  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 /3tErc'  
RandomAccessFile oSavedFile; Iu~<Y(8^q#  
long nPos; 5o>*a>27,A  
vF pKkS343  
7jQVm{{.  
public FileAccessI() throws IOException $$W2{vr7+  
{ ~tV7yY|zr  
this("",0); 7fO<=ei:  
} I"x~ 7
 
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public FileAccessI(String sName,long nPos) throws IOException _dz ZS(7M6  
{ J
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oSavedFile = new RandomAccessFile(sName,"rw"); \=
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this.nPos = nPos; N
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oSavedFile.seek(nPos); C984Ee  
} W[a"&,okqO  
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)G?\{n-  
public synchronized int write(byte[] b,int nStart,int nLen) pwS"BTZ  
{ f-|zh#L  
int n = -1; u*W! !(P/  
try{ zJl;|E".  
oSavedFile.write(b,nStart,nLen); ,EVPnH[F~  
n = nLen; 2<p@G#(  
} k9<UDg_ Y  
catch(IOException e) E i>GhvRM  
{ WiB~sIp  
e.printStackTrace ();
d!}oS<6  
} XEagN:  
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return n; :8@eon}  
} j (Q#NFT7  
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} h(~/JW[  
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/* %8%|6^,  
**SiteInfoBean.java %#~wFW|]x  
*/ CDXN%~0h  
package NetFox; $F9w0kz:,*  
i=]
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L-rV+?i`6f  
public class SiteInfoBean { DO~[VK%|  
)?{!7/H F@  
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private String sSiteURL; //Site's URL Y<(7
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private String sFilePath; //Saved File's Path nTD%i~t~o  
private String sFileName; //Saved File's Name 2p#d  
private int nSplitter; //Count of Splited Downloading File &z5?]`ALu  
1%R${Qhr  
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public SiteInfoBean() &!O?h/&X3  
{//nSplitter的缺省值为5 0*tnJB  
//default value of nSplitter is 5 o<Mccj  
this("","","",5); K@xMPB8in  
} ~TXu20c  
rtQ{  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) u0sN[<  
{ $gz8! f?  
sSiteURL= sURL; F?]J`F\I  
sFilePath = sPath; vE8'B^h1  
sFileName = sName; 2|i
1}  
this.nSplitter = nSpiltter; UF6U5],`u  
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} L;?F^RK{U  
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public String getSSiteURL() S{8-XiL,  
{ <t
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return sSiteURL; +v5f-CBu  
} skan1wQ  
9
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{jQLr7'  
public void setSSiteURL(String value) ("j;VqYUL  
{ 5lP8#O?=  
sSiteURL = value; N~IAm:G}[  
} 9+@z:j  
((#BU=0iK  
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public String getSFilePath() DbB<8$  
{ C9MK3vtD.  
return sFilePath; <pa-C2Ky  
} d}Guj/cx,  
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public void setSFilePath(String value) pO5j-d*  
{ S^|`*%pq  
sFilePath = value; qzA_ ~=g
 
} )B&`<1Oie  
+zk5du^gZ  
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public String getSFileName() k:j_:C&.  
{ R[m{"2|,Lc  
return sFileName; mbX'*up  
} iRkUL]H@&  
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public void setSFileName(String value) .bP8Z=  
{ e&:%Rr]x  
sFileName = value; L'`Au/%S}  
} i M MKA0JM  
j7a}<\  
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public int getNSplitter() [\<#iRcP  
{ 8au Gz ,"  
return nSplitter; mOHOv61  
} pCo3%(  
"fhQ{b$i  
YIZu{  
public void setNSplitter(int nCount) <A|z  
{ 6LCR ;~ ]  
nSplitter = nCount; <8? F\x@  
} &nVekE:!  
} D4y!l~_,%M  
Bfo#N31F}  
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/* jck(cc=R  
**Utility.java {g`!2"  
*/ -~xQ@+./  
package NetFox; ia;osqW  
L >"O[@  
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public class Utility { n/*" 2  
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public Utility() UY({[?Se  
{ LY)Wwl*wc  
S *J{  
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} %(6+{'j~#  
W)]&G}U<  
//线程睡眠 p$x>I3C(\  
public static void sleep(int nSecond) J"GsdLG.-  
{ qLxcr/fK  
try{ VB4V[jraCF  
Thread.sleep(nSecond); h`O$L_Z  
} '-n Iy$>  
catch(Exception e) F !OD*]  
{ |&-*&)iD|w  
e.printStackTrace (); eY?OUS  
} ZBx,'ph}4  
} F 2zUz[  
)G, S7A  
//日志 kCz2uG)l  
public static void log(String sMsg) ;=^J_2ls  
{ "SQyy  
System.err.println(sMsg); NJd4( P  
} VyYrL]OrA  
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H
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public static void log(int sMsg) nSQ]qH&4d  
{ Q"eqql<h#  
System.err.println(sMsg); >c Tt2v  
} 3$K[(>s  
} JgP%4)]LV  
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}2*qv4},!  
/* ?z-nY,'^uq  
**TestMethod.java W=+AU!%  
*/ XUR#|  
package NetFox; |?^N@  
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:@E^oNKa0  
public class TestMethod { hR2 R  
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public TestMethod() + `'wY?  
{ ///xx/weblogic60b2_win.exe U+4[w`a}  
try{ ]goVQ'Y  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 8p}z~\J{a:  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Gf.xr%mUZr  
SiteFileFetch fileFetch = new SiteFileFetch(bean); d Efk~V\  
fileFetch.start();
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} ']c;$wP
 
catch(Exception e){e.printStackTrace ();} iK1{SgXrFI  
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} @V1FBw9S!@  
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public static void main(String[] args) Xq37:
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{ /4+zT
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new TestMethod(); UL&>]aQ  
} ;$$w`LyP  
} ds+2z=!!e  
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