http断点续传简单实现（java)

/* HzD=F
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**SiteFileFetch.java sN9 SuQ  
*/ &s<'fSI  
package NetFox; /6d:l>4  
import java.io.*; 0 |Y'@&  
import java.net.*; ;OY*`(Id  
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public class SiteFileFetch extends Thread { QP0[  
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SiteInfoBean siteInfoBean = null; //文件信息Bean aIW W[xZ  
long[] nStartPos; //开始位置 v#o<. Ig  
long[] nEndPos; //结束位置 $H2H
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FileSplitterFetch[] fileSplitterFetch; //子线程对象 (&ABfm/t  
long nFileLength; //文件长度 d vTsbs/6  
boolean bFirst = true; //是否第一次取文件 P1Chmg  
boolean bStop = false; //停止标志 SVc5mS|up  
File tmpFile; //文件下载的临时信息 Lyj0$wbH`  
DataOutputStream output; //输出到文件的输出流 3f^~mTY9>]  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） Y~ ( <H e?  
public SiteFileFetch(SiteInfoBean bean) throws IOException #Hyfjj  
{ 2*9rhOK*  
siteInfoBean = bean; yHt `kb2  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); V=DT.u  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); )3RbD#?  
if(tmpFile.exists ()) >Vv
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{ L fx$M  
bFirst = false; |"XxM(Dm  
read_nPos(); E2a00i/9Y  
} 1X$hwkof  
else _;yi
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{ cp\A xWtUZ  
nStartPos = new long[bean.getNSplitter()]; |jwN8@  
nEndPos = new long[bean.getNSplitter()]; p.J+~s4G  
} <4
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} c<J/I_!  
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public void run() 
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{ g4fe(.?c,  
//获得文件长度 Z_Z; g]|!  
//分割文件 f}U@e0Lsb  
//实例FileSplitterFetch %HK\  
//启动FileSplitterFetch线程 {Y#
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//等待子线程返回 rS/}!|uAu  
try{ >:yU bo)  
if(bFirst) 4:S?m(ah/  
{ JSOgq/\  
nFileLength = getFileSize(); />E:}1}{  
if(nFileLength == -1) 3~&h9#7Ke  
{ :4, OA  
System.err.println("File Length is not known!"); (@y te  
} QY]G+3W  
else if(nFileLength == -2) {f kP|d  
{ @p}"B9h*^  
System.err.println("File is not access!"); y8QJ=v* B  
} n'-?CMH`  
else <R>%DD=v^  
{ uh_2yw_  
for(int i=0;i<nStartPos.length;i++) X_nxC6[m%  
{ Y']D_\y  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); = rLL5<  
} 6rD Oa~<B  
for(int i=0;i<nEndPos.length-1;i++) [O52Bn  
{ 4`Z8EV  
nEndPos = nStartPos[i+1];
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} C
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nEndPos[nEndPos.length-1] = nFileLength; L[s8`0  
} KnjowK  
} [esR!})  
}co*%F{1  
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//启动子线程 ^Td_B03)  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; OKH4n/pq  
for(int i=0;i<nStartPos.length;i++) MPg"n-g*  
{ ; OpN&q+  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), CS<,qvLpL  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), >TqMb8e_  
nStartPos,nEndPos,i); JO `KNI  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ZXR#t?D  
fileSplitterFetch.start(); 
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} lIlmXjL0  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 8A3pYW-  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); HI}9"(t}  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", !u;r<:g!  
nEndPos = " + nFileLength); zu@5,AH  
// fileSplitterFetch[nPos.length-1].start(); t@(`24  
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KS6H`Mm}/  
//等待子线程结束 UD@u hL  
//int count = 0; UFLN/  
//是否结束while循环 ;F:~HrxT}  
boolean breakWhile = false; #kt3l59Ty  
keYvscRBI  
:~1sF_  
while(!bStop) ,GH;jw)P  
{ ^*fZ  
write_nPos(); :GaK.W q  
Utility.sleep(500); ojA i2uz  
breakWhile = true; pDg_^
|  
8'Y7lOXS  
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for(int i=0;i<nStartPos.length;i++) 1sT%g}w@|  
{ |<q9Ee  
if(!fileSplitterFetch.bDownOver) gPu0j4&-  
{ =h<LlI^v  
breakWhile = false; v_$'!i$  
break; Gc'CS_L  
} > (.V(]{3y  
} _FJ,, /~  
if(breakWhile) 8a;I,DK=j  
break; w>q:&Q  
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//count++; W=9Zl(2C  
//if(count>4) ]^j'2nJv0  
// siteStop(); Snav)Hb'  
} O&Ws*k  
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System.err.println("文件下载结束！"); l-Q.@hG  
} ;hsem,C h7  
catch(Exception e){e.printStackTrace ();} DD4fV`:kG  
} [= GVK  
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&%ZiI@O-  
//获得文件长度 TC=djC4$/  
public long getFileSize() o?Wp[{K  
{ Imi#$bF6  
int nFileLength = -1; 6U`<+[K7  
try{ &s|a\!>l  
URL url = new URL(siteInfoBean.getSSiteURL()); |"Rl_+d7D  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); z`^DQ8+\j  
httpConnection.setRequestProperty("User-Agent","NetFox"); ?)ROQ1-#@  
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int responseCode=httpConnection.getResponseCode(); 4K(AXk  
if(responseCode>=400) sU/R$Nbr  
{ GomTec9.  
processErrorCode(responseCode); ):Vzv  
return -2; //-2 represent access is error 7h3#5Y  
} *f?z$46  
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String sHeader; #s!q(Rc  
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for(int i=1;;i++) epWO}@ b a  
{ /lC&'hT  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); sUfYEVjr  
//Utility.log(in.readLine()); >|"mhNF  
sHeader=httpConnection.getHeaderFieldKey(i); _m  *8f\  
if(sHeader!=null) Zj*kHjn"
 
{ L+c7.l.yT  
if(sHeader.equals("Content-Length")) qNLG-m,n<  
{ ~1NK@=7T  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 2 f"=f^rf  
break; #9{9T"ed  
} 9'qU4I  
} YSvZ7G(m>  
else q\B048~KK  
break; [Ipg",Su;f  
} [BH^SvE  
} jWg7
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catch(IOException e){e.printStackTrace ();} ~4YLPMGKl  
catch(Exception e){e.printStackTrace ();} {EoRY/]  
#q06K2  
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Utility.log(nFileLength); 7# /c7
 
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return nFileLength; &?],uHB?d  
} ha;Xali ]  
Y=%SK8]Q;  
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//保存下载信息（文件指针位置） _e ]jz2j  
private void write_nPos() `sS\8~A  
{ uG|d7LS,%  
try{ Y4\BHFq  
output = new DataOutputStream(new FileOutputStream(tmpFile)); acSm+t  
output.writeInt(nStartPos.length); _?vh#6F  
for(int i=0;i<nStartPos.length;i++) "!9hcv-;  
{ Lv`*+;1K  
// output.writeLong(nPos); B]`!L/  
output.writeLong(fileSplitterFetch.nStartPos); n>)'!  
output.writeLong(fileSplitterFetch.nEndPos); /D]V3|@E  
} X"hoDg  
output.close(); sG/mmZHYzr  
} d$3;o&VUNI  
catch(IOException e){e.printStackTrace ();} wIrjWU2  
catch(Exception e){e.printStackTrace ();} .HM1c  
} Y:~A-_  
l1_Tr2A}7/  
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//读取保存的下载信息（文件指针位置） +>em !~
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private void read_nPos() hnQDm$k  
{ GTj=R$%09  
try{ o]&w"3vOP0  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile));
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int nCount = input.readInt(); 9@Iz:!oqb  
nStartPos = new long[nCount]; '`-W!g[ >  
nEndPos = new long[nCount]; NF}QQwG3  
for(int i=0;i<nStartPos.length;i++) $[L8UUHY<8  
{ $`2rtF  
nStartPos = input.readLong(); fZ9EE3  
nEndPos = input.readLong(); yqy5i{Y
 
} )yV|vn  
input.close(); 19Cs 3B\4  
} Vv
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catch(IOException e){e.printStackTrace ();} }Htnhom0n  
catch(Exception e){e.printStackTrace ();} |Ef\B]Ns  
} pJ` M5pF  
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private void processErrorCode(int nErrorCode) Quc,,#u  
{ yGNZw7^(  
System.err.println("Error Code : " + nErrorCode); 7,i}M  
} *wgHa6?+7  
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/Hox]
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//停止文件下载 iqzl(9o.D  
public void siteStop() vyME  
{ oD$8(  
bStop = true; *K9I+t"g  
for(int i=0;i<nStartPos.length;i++) U4DQ+g(A  
fileSplitterFetch.splitterStop(); S$CO T)7  
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]Qo.X~]  
} |x2+O  
} 1'skCR|!<  
//负责部分文件的抓取 j\^0BTZ  
**FileSplitterFetch.java Oz\mIVC#  
*/ 2Xu?/yd  
package NetFox; t/;@~jfr@  
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j@kL`Q\&I  
import java.io.*; h8b*=oq  
import java.net.*; s6#@S4^=\  
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public class FileSplitterFetch extends Thread { hK!Z~  
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String sURL; //File URL f8ap+][  
long nStartPos; //File Snippet Start Position 2?",2x09  
long nEndPos; //File Snippet End Position "6T: &>  
int nThreadID; //Thread's ID 5ryzAB O\2  
boolean bDownOver = false; //Downing is over =j)y.
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boolean bStop = false; //Stop identical p*11aaIbp~  
FileAccessI fileAccessI = null; //File Access interface :ZP4(}  
l!n<.tQW  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Z_Gb
9  
{ L{v^:  
this.sURL = sURL; x.V6C0|6"  
this.nStartPos = nStart; 8q
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this.nEndPos = nEnd; TY|5O! <  
nThreadID = id; fI{ZElPp  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 b.qp&2A  
} nI1DLVt  
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public void run() RwH<JaL:  
{ ~~U2Sr  
while(nStartPos < nEndPos && !bStop) ?
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{ Hx}K wS  
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try{ OD,"8JF  
URL url = new URL(sURL); |!r.p_Zt  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); cJEOwAN  
httpConnection.setRequestProperty("User-Agent","NetFox"); TBfX1v|Z)  
String sProperty = "bytes="+nStartPos+"-"; O"otzla  
httpConnection.setRequestProperty("RANGE",sProperty); 5K1WfdBX7)  
Utility.log(sProperty); X(D$
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!i0jk,[B=  
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InputStream input = httpConnection.getInputStream(); ZE#f{qF(  
//logResponseHead(httpConnection); j@1rVOmK  
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#!IezvWf  
byte[] b = new byte[1024]; -*[?E!F  
int nRead; =AFTB<7-^  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) +/A`\9QT  
{ tK<GU.+  
nStartPos += fileAccessI.write(b,0,nRead); < bHu9D  
//if(nThreadID == 1) UWdPB2x[  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); @PXb^x#k  
} B]PTe~n^  
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Utility.log("Thread " + nThreadID + " is over!"); #A8d@]Ps  
bDownOver = true; C
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//nPos = fileAccessI.write (b,0,nRead); fvajNP  
} u$%>/c
v  
catch(Exception e){e.printStackTrace ();} ,`7;S,f  
} `aFy2x`3  
} A>"v1W
k  
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7m;2M]BRi  
//打印回应的头信息 4X2XSK4  
public void logResponseHead(HttpURLConnection con) SnK j:|bV  
{ {(}Mu R  
for(int i=1;;i++) %IS'R`;3  
{ ALw5M'6q0\  
String header=con.getHeaderFieldKey(i);
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if(header!=null) [\o+I:,}wi  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); gf!hO$sQ3  
Utility.log(header+" : "+con.getHeaderField(header)); uN`{; Av  
else `{g8A P3  
break; ^}XKhn.S'  
} AL.zF\?  
} /o=V (  
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public void splitterStop() 0dKI+zg
r  
{ kl.)A-6V  
bStop = true; |>(@n{  
} I*e85wef  
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r`]&{0}23  
} Jji~MiMn  
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)hH9VGZq(  
/* IAt;?4  
**FileAccess.java ?^i$} .%W  
*//文件访问(定位，写) q #f U*  
package NetFox; :$&%Pxm  
import java.io.*; lAsDdxB`  
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&z;;Bx0s  
public class FileAccessI implements Serializable{
[@ ]f@Wd  
_A*5BAB:h(  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Dc |!H{Yr  
RandomAccessFile oSavedFile; ]KGLJ~hm>  
long nPos; bS{7*S  
![WX -"lW  
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public FileAccessI() throws IOException zdCeOZ 6  
{ _8C0z=hz  
this("",0); *|MHQp'A  
} V\zf yH\~  
[h8j0Q@Q  
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public FileAccessI(String sName,long nPos) throws IOException yp=Hxf  
{ LTu cs}  
oSavedFile = new RandomAccessFile(sName,"rw"); YmM+x=G:  
this.nPos = nPos; 
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oSavedFile.seek(nPos); u7>b}+ak&  
} @sly-2{e1  
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0$3\DS<E  
public synchronized int write(byte[] b,int nStart,int nLen) QRj><TKi  
{ P F!S  
int n = -1; 4l2i'H  
try{ 6#XB'PR2p  
oSavedFile.write(b,nStart,nLen); \^iPU 27H  
n = nLen; &?^S`V8R*  
} _Zya GDv  
catch(IOException e) !3>(fj+QS  
{ <@FOqi{o{  
e.printStackTrace (); JicAz1P1W  
} hXi^{ntw,  
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return n; l%*KBME  
} PL/as3O^A  
c0]^V>}cl  
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} ; >3q@9\D  
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/* ~lMw*Qw^  
**SiteInfoBean.java $X_JUzb  
*/ JqTkNKi/s  
package NetFox; &P&LjHFK  
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public class SiteInfoBean { y0qrl4S)v  
v4!zB9d  
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private String sSiteURL; //Site's URL }l&Uh&B`  
private String sFilePath; //Saved File's Path vlth\[  
private String sFileName; //Saved File's Name Pl<r*d)h  
private int nSplitter; //Count of Splited Downloading File ]Mi ~vG q  
9;s:Bo  
^,')1r,  
public SiteInfoBean() w#eD5y~'oo  
{//nSplitter的缺省值为5 `O(ec  
//default value of nSplitter is 5 ZzLmsTtzIu  
this("","","",5); {.$5:<8aC  
} -frmvNJ F  
MB :knj  
#}L75  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 0ZPwE
P  
{ Xu`c_  
sSiteURL= sURL; IRNL(9H  
sFilePath = sPath; j*>+^g\Q6  
sFileName = sName; ,ii*[{X?  
this.nSplitter = nSpiltter; &=H{ 36i@  
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} $9<q'hf<w  
<uUQ-]QOIh  
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public String getSSiteURL() Ov"]&e(I[  
{ PE3FuJGz  
return sSiteURL; Mg;%];2Nt  
} $Z6g/bD`E  
mZ 39 s  
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public void setSSiteURL(String value) ;]zV ?9  
{ K,e"@G  
sSiteURL = value; 0UZ>y/ C)=  
} QQUeY2}  
\O5`R-  
|m7
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public String getSFilePath() %0C<_drW  
{ #j -
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return sFilePath; sS;6QkI"y  
} :+{G|goZ*  
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public void setSFilePath(String value) 
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{ z(2pl}  
sFilePath = value; <+UEM~)  
} 4Gs#_|!  
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public String getSFileName() O*{<{3  
{ P
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return sFileName; "*W:  
} Q\Dx/?g!vx  
r!SMF]?SJ  
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public void setSFileName(String value) u~n*P``{  
{ P'.MwS  
sFileName = value; .zQ:u{FT  
} 7S$Am84%  
51j5AbFQ"  
)QYg[<e6  
public int getNSplitter() )[RLCZ  
{ [xzgk[>5  
return nSplitter; \J[m4tw^  
} !.1oW
(  
^Pl(V@  
c} )U:?6  
public void setNSplitter(int nCount) #\s*>Z  
{ F: %-x=q  
nSplitter = nCount; l?pF
?({  
} NRu_6~^^  
} i ,Cvnp6Lv  
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.j?`U[V%a  
/* Yt&Isi +  
**Utility.java hhd%j6  
*/ 'i5 VU4?K  
package NetFox; `)V1GR2 ES  
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e$]`  
public class Utility { K"u-nroHW  
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public Utility() Pyh+HD\  
{ \7rAQ[\#V  
.nN=M>#/  
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} 6. N?=R  
iUSP+iC,  
//线程睡眠 *69{#qN  
public static void sleep(int nSecond) -e<d//>  
{ e RY2.!  
try{ aT}Mn(F*?  
Thread.sleep(nSecond); ,/0Q($oz
 
} rR`'l=,t  
catch(Exception e) \kSoDY`l&  
{ G
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e.printStackTrace (); y/=:F=H@w  
} :})(@.H  
} yg({g "  
m$<LO%<~p  
//日志 HYVSi3[  
public static void log(String sMsg)
\:]  
{  x{K^u"  
System.err.println(sMsg); hojP3 [  
} ,b[}22  
$!Z><&^/  
l{b<rUh5W  
public static void log(int sMsg) s18o,Zs'  
{ lG
rp^  
System.err.println(sMsg); ;:<z hO  
} |;xm-AM4r  
} A/5??3H  
fM,!9}<  
e7e6b-"_2  
/* <Z{pjJ/  
**TestMethod.java N>h/!# ZC  
*/ HIiMq'H^  
package NetFox; #a1zk\R3  
LX<arHz  
V~#e%&73FH  
public class TestMethod { W|@
7I@@$"  
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public TestMethod() w2*.3I,~)B  
{ ///xx/weblogic60b2_win.exe 1{6BU!  
try{ %8c <C  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); V11(EZJ/j  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); vW6 a=j8  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 5cc;8i  
fileFetch.start(); J%VcvBaJm  
} 0$=Uhi  
catch(Exception e){e.printStackTrace ();} ?O(@BT  
d)@Hx8  
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} 'I$-h<W  
8:#\g  
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public static void main(String[] args) (EW<Ggi  
{ 5>9KW7^L  
new TestMethod(); i4<&zj})  
} HCBZ*Z-  
} FHztF$Z  
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