http断点续传简单实现（java)

/* 1L3L!@  
**SiteFileFetch.java IRLT-  
*/ |[0|j
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package NetFox; 0nC%tCV'  
import java.io.*; cxVnlgq1  
import java.net.*; ,+0_kndR  
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public class SiteFileFetch extends Thread { 0q81H./3  
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SiteInfoBean siteInfoBean = null; //文件信息Bean Vg0Rc t  
long[] nStartPos; //开始位置 "gYn$4|R7*  
long[] nEndPos; //结束位置 zXB.)4T  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 3(X"IoNQ  
long nFileLength; //文件长度 J 5~bs*a8  
boolean bFirst = true; //是否第一次取文件 ">|fB&~A  
boolean bStop = false; //停止标志 ?me0J3u_  
File tmpFile; //文件下载的临时信息 Bc$t`PI  
DataOutputStream output; //输出到文件的输出流 +Bgy@.a?  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） , j7&(V~  
public SiteFileFetch(SiteInfoBean bean) throws IOException qXgg"k%A\  
{ ><%z~s  
siteInfoBean = bean; PKk_9Xd  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); *?cE]U6;  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); .:E%cL +h  
if(tmpFile.exists ()) cl[rgj  
{ zl$'W=[rFs  
bFirst = false; M,zUg_@  
read_nPos(); d(<[$3.  
} sRqFsj}3e  
else bNi\+=v<Ys  
{ ?FJU>+{">  
nStartPos = new long[bean.getNSplitter()]; K.B!-<  
nEndPos = new long[bean.getNSplitter()]; =5is
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} 3x=T&X+  
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} XI@;;>D1=U  
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public void run() Zgd| J T7  
{ |4UW.dGHPo  
//获得文件长度 mGb,oj7l  
//分割文件 Ny\p$v "p  
//实例FileSplitterFetch Eu2@%2}P  
//启动FileSplitterFetch线程 [5yLg  
//等待子线程返回 3U^E<H  
try{ 1$H*E~  
if(bFirst) xj\!Sn2  
{ )ERmSWq/u  
nFileLength = getFileSize(); 8tJB/Pw`S  
if(nFileLength == -1) UU~S{!*+L  
{ j&~`H:=E  
System.err.println("File Length is not known!"); ,t2Mur  
} 3@7IY4>o  
else if(nFileLength == -2) z$C}V/Ey  
{ h)7hk*I  
System.err.println("File is not access!"); A0JlQE&U  
} DC+p s  
else &V"9[0  
{ 2"~|k_  
for(int i=0;i<nStartPos.length;i++) e*K1";  
{ O(pa;&"  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); hUR>NUK@8  
} },#@q_E  
for(int i=0;i<nEndPos.length-1;i++) 4b5'nu  
{ ;l4epN  
nEndPos = nStartPos[i+1]; J7a_a>Y  
} rW),xfo0  
nEndPos[nEndPos.length-1] = nFileLength; 4@0y$Dv\  
} D6z*J?3^#&  
} '
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//启动子线程 a\_?zi]s&,  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; zw,( kv  
for(int i=0;i<nStartPos.length;i++) ny++U;qi  
{ L JW0UF|  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), $<DcbJW  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Z2@_F7cXt  
nStartPos,nEndPos,i); ;cpQ[+$nKp  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 9S<g2v  
fileSplitterFetch.start(); {PBm dX  
} C]dK/~Z#r  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), lE|Hp  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 7gxC xfL$  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", dAba'|Y  
nEndPos = " + nFileLength); Fm-D>PR
 
// fileSplitterFetch[nPos.length-1].start(); Q95`GuI@  
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//等待子线程结束 iCXKi7  
//int count = 0; ZkA05wPZ#  
//是否结束while循环 /k_?S?  
boolean breakWhile = false; <0sT  
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h
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while(!bStop) QJ%[6S  
{ a Byetc88/  
write_nPos(); ,RXfJh  
Utility.sleep(500); .).}ffhOL  
breakWhile = true; A(2!.Y 2?*  
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for(int i=0;i<nStartPos.length;i++) I%?ia5]H  
{ MGbl-,]  
if(!fileSplitterFetch.bDownOver) ps@;Z?Q  
{ \""sf{S9  
breakWhile = false; 8n'"RaLQ8  
break; xtq='s8e  
} ud`!X#e~  
} 5&V
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if(breakWhile) m,|)$R  
break; q-<t'uhs[  
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//count++; Ho!dtEs  
//if(count>4) ^hyY,X  
// siteStop(); >0c4C<_  
} h8zl\  
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System.err.println("文件下载结束！"); mSFh*
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}
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catch(Exception e){e.printStackTrace ();} [OU[i(,{  
} YYs/
r  
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//获得文件长度 H="E#AC%8/  
public long getFileSize() (fUpj^E)p  
{ 'jr[ ?WQ  
int nFileLength = -1; L5{DWm~@  
try{ kaG@T,pH(  
URL url = new URL(siteInfoBean.getSSiteURL()); WETnrA"N  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); D.;iz>_}Y  
httpConnection.setRequestProperty("User-Agent","NetFox"); fC<pCdsg  
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int responseCode=httpConnection.getResponseCode(); duT'$}2@>  
if(responseCode>=400) >JUOS2  
{ 0*{2
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processErrorCode(responseCode); ,)beK*Iw  
return -2; //-2 represent access is error F
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} 6-6ha7]s  
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String sHeader; |%~Zo:Q<$>  
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for(int i=1;;i++) \YMe&[C:o  
{ _GF{Duxh  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); +ebmve \+  
//Utility.log(in.readLine()); appWq}db  
sHeader=httpConnection.getHeaderFieldKey(i); ^0T DaZDLp  
if(sHeader!=null) tsf)+`vt  
{ d")TH3pG  
if(sHeader.equals("Content-Length")) gi#g)9HG  
{ !Sj
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nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); W9M~2< L  
break; %}/|/=  
} tmVGJ+gz  
} v3I-i|L<)  
else P g.j]  
break; Yk @/+PE  
} 6t!PHA  
} hgPzx@  
catch(IOException e){e.printStackTrace ();} glI4Jb_[  
catch(Exception e){e.printStackTrace ();} s1kG:h2|$  
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Utility.log(nFileLength); C>~ms2c  
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return nFileLength;  U rL|r.  
} LZ-&qh  
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//保存下载信息（文件指针位置） 3z~d
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private void write_nPos() 2R=Fc@MXs  
{ < ?{ic2j#  
try{ /O{iL:`  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 'J1
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output.writeInt(nStartPos.length); )1iqM]~;B  
for(int i=0;i<nStartPos.length;i++) rjWn>M  
{ IDn$w^"  
// output.writeLong(nPos); F`8B PW
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output.writeLong(fileSplitterFetch.nStartPos); #C#*yE  
output.writeLong(fileSplitterFetch.nEndPos); h*B7UzCg  
} {"WfA  
output.close(); 2|}`?bY]i`  
} f3oGB*5>  
catch(IOException e){e.printStackTrace ();} hj+iB,8  
catch(Exception e){e.printStackTrace ();} Mv_-JE9#>o  
} ~/l5ys  
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//读取保存的下载信息（文件指针位置） YQ
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private void read_nPos() )Rc  
{ ~pWV[oUD  
try{ :N#8|;J1Fl  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ["N_t:9I  
int nCount = input.readInt(); k
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nStartPos = new long[nCount]; 3;Y9<  
nEndPos = new long[nCount]; @|6#]&v`  
for(int i=0;i<nStartPos.length;i++) $az9Fmta  
{ +"GBuNh  
nStartPos = input.readLong(); @wPyXl  
nEndPos = input.readLong(); '4e, e|r  
} U-:"Wx%G  
input.close(); wY xk[)&Y  
} *&O4b3R  
catch(IOException e){e.printStackTrace ();} <swfYT!N  
catch(Exception e){e.printStackTrace ();} kK%@cIXS3  
} CAbR+y  
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private void processErrorCode(int nErrorCode) 6^NL>|?  
{ 8k9Yoht  
System.err.println("Error Code : " + nErrorCode); o>75s#= b=  
} M.u1SB0  
b-
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//停止文件下载 =Ohro'   
public void siteStop() T o$D[-  
{ vf0 fa46  
bStop = true; |*>s%nF|  
for(int i=0;i<nStartPos.length;i++) #I}w$j i  
fileSplitterFetch.splitterStop(); Wf{&D>  
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} !t!'  
} mTBSntZx  
//负责部分文件的抓取 #7Jvk_r9Y  
**FileSplitterFetch.java DDBf89$\  
*/ E++3GagdiD  
package NetFox; 8;y\Ln?B  
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import java.io.*; p|n!R $_g\  
import java.net.*; ZfVw33z  
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public class FileSplitterFetch extends Thread { 4Hq6nT/  
~9Cw5rwH<;  
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String sURL; //File URL KMP[
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long nStartPos; //File Snippet Start Position lXi
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long nEndPos; //File Snippet End Position hka`STK{  
int nThreadID; //Thread's ID O&}`R5Y;  
boolean bDownOver = false; //Downing is over B4t,@,\O  
boolean bStop = false; //Stop identical }iRRf_   
FileAccessI fileAccessI = null; //File Access interface /[+qw%>  
=|V[^#V  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException cpu|tK.t  
{ xp%LXxj  
this.sURL = sURL; Z> <,t~o}  
this.nStartPos = nStart; C
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this.nEndPos = nEnd; g`I$U%a_2  
nThreadID = id; p+}eP|N  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 C *]XQ1F4  
} % |G"ZPO?  
[[
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public void run() \4Z"s[8}  
{ j$Vtd&  
while(nStartPos < nEndPos && !bStop) 4%*`'o$_  
{ :~\ y
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try{ <4Ik]Uz^  
URL url = new URL(sURL); DEt;$>tl 5  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); fKNDl\SD  
httpConnection.setRequestProperty("User-Agent","NetFox"); nmoC(| r  
String sProperty = "bytes="+nStartPos+"-"; q],/%W  
httpConnection.setRequestProperty("RANGE",sProperty); 9&Ny;oy#6  
Utility.log(sProperty); D)bR-a_^  
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InputStream input = httpConnection.getInputStream(); Bi|-KS.9  
//logResponseHead(httpConnection); 'J:xTp  
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byte[] b = new byte[1024]; [Y8ot-6  
int nRead; m`#UV-$J  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) tx]!|x" F  
{ -9yWf8;  
nStartPos += fileAccessI.write(b,0,nRead); 28O3N;a  
//if(nThreadID == 1) T^H`$;\  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); _SqUPTb"u  
} m-'+)lB  
.1h1J   
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Utility.log("Thread " + nThreadID + " is over!"); 
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bDownOver = true; 8[d6 s  
//nPos = fileAccessI.write (b,0,nRead); M][Zu[\*  
} V?4G~~F  
catch(Exception e){e.printStackTrace ();} V#\iO  
} nACKSsWqI  
} :.?%e{7  
*.zC9Y,  

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//打印回应的头信息 U_AmRiy  
public void logResponseHead(HttpURLConnection con) zN>tSdNkI-  
{ H)NT2@%{P  
for(int i=1;;i++) T@j@IEGH  
{
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String header=con.getHeaderFieldKey(i); Jl{g"N{2u'  
if(header!=null) e'&<DE)  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); leO..M  
Utility.log(header+" : "+con.getHeaderField(header)); ef]60OtP  
else .h\[7r  
break; d5 U+]g  
} ?o_D#gG*  
} ,{s
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/  
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public void splitterStop() "U iv[8B  
{ \-RVPa8k  
bStop = true; Yjix]lUXVf  
} #<gD@Jybu  
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} 7=pJ)4;ZA  
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/* |v= */
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**FileAccess.java YE1X*'4  
*//文件访问(定位，写) [+>cW0a  
package NetFox; uOQl;}Lk5  
import java.io.*; A9ru]|?  
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public class FileAccessI implements Serializable{ W3Dtt-)E  
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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 {{Z3M>Q  
RandomAccessFile oSavedFile; dS~#Lzm  
long nPos; Gcd'-1  
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public FileAccessI() throws IOException KmaMS(A(3  
{ _kJW/3eE  
this("",0); ^Mi&2AvS  
} E~eSHJ(oR7  
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public FileAccessI(String sName,long nPos) throws IOException \,yX3R3}.~  
{ kac]Rh8vO  
oSavedFile = new RandomAccessFile(sName,"rw"); 4 X6_p(  
this.nPos = nPos; !&@
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oSavedFile.seek(nPos); 46M?Gfd,X  
} bs\7 juHt  
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public synchronized int write(byte[] b,int nStart,int nLen) Afo qCF  
{ z*O
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int n = -1; wd0*"c@  
try{ A<P rsk!  
oSavedFile.write(b,nStart,nLen); ff.;6R\  
n = nLen; i8>^{GODR  
}
[5$Y>Tr!  
catch(IOException e) 'I1^70bB  
{ fv?vfI+m  
e.printStackTrace (); GJbU1k]  
} 0ZjinWkR[  
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return n; +
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} oO~LiK>  
@/0-`Y@?  
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} ;_?RPWZ;MO  
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H?W8_XiN  
/* hF7#i_UN<  
**SiteInfoBean.java 4/M~#  
*/ Uh8c!CA8:\  
package NetFox; "[p-I
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\1cJ?/$_Of  
?(P3ZTk?.  
public class SiteInfoBean { :igURr
  
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j SXVLyz  
private String sSiteURL; //Site's URL y%=t((.Z  
private String sFilePath; //Saved File's Path B kWoK/f4  
private String sFileName; //Saved File's Name 2'5%EQW;0y  
private int nSplitter; //Count of Splited Downloading File 8sGaq [  
*:hHlH* t1  
5p`.RWls  
public SiteInfoBean() D_)n\(3  
{//nSplitter的缺省值为5 s'^"s_j  
//default value of nSplitter is 5 Y76UhtYH  
this("","","",5); NY9\a[[^[8  
} Gtpl5gQH  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) jj8h>"d  
{ @O Rk  
sSiteURL= sURL; euc|G Xs  
sFilePath = sPath; *mTx0sQz(J  
sFileName = sName; =&xNdc  
this.nSplitter = nSpiltter; yttI
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} d-sK{ZC"y  
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public String getSSiteURL() ^P !}
"  
{ K|g+Wt^tQ  
return sSiteURL; fkmN?CU{1%  
} 8s#2Zv  
ae`6hW2  
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public void setSSiteURL(String value) X23#y7:  
{ -VVJf5/  
sSiteURL = value; G>yTv`-  
} :Lze8oY(D}  
zxffjz,Fe:  
oz[: T3oE>  
public String getSFilePath() `bx}!;{lx  
{ z),@YJU"z  
return sFilePath; 8C(@a[V  
} !H[K"7w  
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&q0s8'qA  
public void setSFilePath(String value) a-<&(jV  
{ m"y_@Jk  
sFilePath = value; L?slIGp%-  
} -U#e  
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8) 1+j>OQ  
public String getSFileName() _Nmc1azS  
{ Iurb?  
return sFileName; [~#]p9|L  
} a
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>GV= %  
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public void setSFileName(String value) m/(f?M l  
{ >wOqV!0<  
sFileName = value; e qzmEg  
} OX!<{9o  
vv% o+r-t  
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public int getNSplitter() 9yt)9f  
{ x%d\}%]  
return nSplitter; XFv)]_G  
} s}5,<|DL  
e0; KmQjG  
SZ'2/#R>  
public void setNSplitter(int nCount) [@LA<Z_
 
{ N=[# "4I  
nSplitter = nCount;
}2nmfm!  
} mOQN$d[  
} 
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{InD/l'v6n  
/* ap y#8]  
**Utility.java XD=p:Ezh  
*/ Ns}BE H  
package NetFox; WY)*3?  
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rMy(NAo
_  
public class Utility { 'W2B**}  
?7]UbtW[  
/ 80Q  
public Utility() 2Sg^SZFH+o  
{ ,/uVq
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0 P]+/  
>q!:*  
} ZP}NFh%,u  
#o/  
//线程睡眠 Z>)M{25  
public static void sleep(int nSecond) g&<3Kl  
{ ,VdNP  
try{ e[ 9  
Thread.sleep(nSecond); 2YV*U_\L  
} oM~;du  
catch(Exception e) Pv#>j\OR&  
{ (+w>hCI  
e.printStackTrace (); Z;qgB7-M  
} ]8;2Oh   
} 9ER!K  
A0f98?j^  
//日志 Uxl7O4J@H  
public static void log(String sMsg) A<$w }Fy;  
{ de<T5/  
System.err.println(sMsg); ]b6gZ<  
} }S_#*N)i  
zY^QZceq"  
X]T&kdQ6q  
public static void log(int sMsg) WH6Bs=G\}  
{ bAVlL&^@|  
System.err.println(sMsg); dPmtU{E<M  
} 1@"os[9  
} alV{| Vf[6  
WnkIi,<  
\]y /EOT  
/* KW 78J~u+  
**TestMethod.java &]_2tN=S$  
*/ lv=rL  
package NetFox; =(cfo_B@K  
7(W"NF{r  
snm1EPj  
public class TestMethod { u#^~([I  
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public TestMethod() }VDJ  
{ ///xx/weblogic60b2_win.exe 5xIOi(3`Q  
try{ "
t!_bma  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); :5, k64'D  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); P'<D0   
SiteFileFetch fileFetch = new SiteFileFetch(bean); WLkfo6Nw  
fileFetch.start(); 7
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} XRx^4]c  
catch(Exception e){e.printStackTrace ();} sG K7Uy  
@||GMA+|  
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} 8^2E77s4U  
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public static void main(String[] args) 2Cgq&\wS  
{ NS3qNj  
new TestMethod(); 1kdQh&~G  
} 1h,m  
} t*dd/a  
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