http断点续传简单实现（java)

/* @3@oaa/v  
**SiteFileFetch.java ywS2`(  
*/ IU*w'a  
package NetFox; si|DxDx  
import java.io.*; wqyrs|P  
import java.net.*; Q+]
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public class SiteFileFetch extends Thread { j/
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SiteInfoBean siteInfoBean = null; //文件信息Bean MU/3**zoW  
long[] nStartPos; //开始位置 _RcFV  
long[] nEndPos; //结束位置 C
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FileSplitterFetch[] fileSplitterFetch; //子线程对象 L[s8`0  
long nFileLength; //文件长度 KnjowK  
boolean bFirst = true; //是否第一次取文件 4v("qNw#  
boolean bStop = false; //停止标志 "\l O1D  
File tmpFile; //文件下载的临时信息 c7fQ{"f 3B  
DataOutputStream output; //输出到文件的输出流 <.lT.>'?  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） *tD`X(K  
public SiteFileFetch(SiteInfoBean bean) throws IOException (T]<  
{ LAT%k2%Wx  
siteInfoBean = bean; 3?rYt:Uf!  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 8w|-7$ v  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 8^FAeV#  
if(tmpFile.exists ()) F3L'f2yBG  
{ klK
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bFirst = false; u{_jweZ  
read_nPos(); 9gLUM$Kd  
} h*JzJ0X  
else />,Tq!i\4}  
{ O5:2B\B  
nStartPos = new long[bean.getNSplitter()]; =Hs[peO*  
nEndPos = new long[bean.getNSplitter()]; s/"?P/R  
} FNyr0!t,  
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} !PIpvx{aX  
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public void run() xc HG5bg|  
{ ojA i2uz  
//获得文件长度 pDg_^
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//分割文件 V?*\ISB`}  
//实例FileSplitterFetch AKbrXKx  
//启动FileSplitterFetch线程 *Ou)P9~-L  
//等待子线程返回 ]tzO)c)w;  
try{ zL<<`u?  
if(bFirst) [4_JK  
{ ;F;"Uw  
nFileLength = getFileSize(); .%'$3=/oe  
if(nFileLength == -1) L
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{ 8a;I,DK=j  
System.err.println("File Length is not known!"); w>q:&Q  
} qf7oG0  
else if(nFileLength == -2) .1&~@e%=-  
{ }zkMo?  
System.err.println("File is not access!"); *yx&4)Or  
} HZHzjrx  
else n4YedjHSN  
{ y[W<vb+F  
for(int i=0;i<nStartPos.length;i++) \ M_}V[1+  
{ F;Lg w^1!  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 4KkjBP
V  
} H*Tc.Ie  
for(int i=0;i<nEndPos.length-1;i++) [9:'v@Ph  
{ JFvVRGWB  
nEndPos = nStartPos[i+1]; RK
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} 9EE},D  
nEndPos[nEndPos.length-1] = nFileLength; P9\!JH!  
} .Kn)sD1  
} d0;$k,  
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//启动子线程 J9kmIMq-C  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; FHu -';  
for(int i=0;i<nStartPos.length;i++) c~1X/,biA  
{ nS53mLU)  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), *,UD&N_)*6  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), i"h '^6M1  
nStartPos,nEndPos,i); ,1s,G]%M  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Gxtb@`f  
fileSplitterFetch.start(); I4%p?'i,C  
} 7h3#5Y  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), *f?z$46  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Gg\805L@  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 
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nEndPos = " + nFileLength); 9 NO^
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// fileSplitterFetch[nPos.length-1].start(); !w!}`|q  
qOusO6  
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//等待子线程结束 lDQ'
  
//int count = 0; RO([R=.`/  
//是否结束while循环 Z]1=nSv  
boolean breakWhile = false; eu]t.Co[X  
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while(!bStop) !F|mCEU  
{ (&w'"-`  
write_nPos(); lYS+EVcR  
Utility.sleep(500); me#?
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breakWhile = true; $ON4nx  
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for(int i=0;i<nStartPos.length;i++) Nvlfi8.  
{ $ylQ \Y'  
if(!fileSplitterFetch.bDownOver) \G3P[
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{ j=%^CRum  
breakWhile = false; hU}!:6G%[P  
break; 98%M`WY  
} 
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} 1;\A./FVv  
if(breakWhile) a^vXwY  
break; #!m`A+!~!  
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//count++; Y\.ds%G  
//if(count>4) _e ]jz2j  
// siteStop(); _86#$|kw  
} QEh_2  
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System.err.println("文件下载结束！"); _?vh#6F  
} "!9hcv-;  
catch(Exception e){e.printStackTrace ();} QW5S=7  
} 8>E_bxC  
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//获得文件长度 ,_JhvPWR,)  
public long getFileSize() uN:|4/;{&  
{ pzo9?/-  
int nFileLength = -1; >y2;sJ4]D%  
try{ wH=L+bA>a  
URL url = new URL(siteInfoBean.getSSiteURL()); GwOn&EpY!  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); arCi$:-z@  
httpConnection.setRequestProperty("User-Agent","NetFox"); !J5k?J&{=  
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int responseCode=httpConnection.getResponseCode(); 5}4f[   
if(responseCode>=400) W>ziA  
{ {*=+g>RgD  
processErrorCode(responseCode); UBmD 3|Zo  
return -2; //-2 represent access is error re\@v8w~  
} LqH<HGMFD  
2k }:)]m  
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String sHeader; ;g3z?Uz)  
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for(int i=1;;i++) AoaRlk-#  
{ E&\dr;{7  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); >@NH Al  
//Utility.log(in.readLine()); uhyw?#f  
sHeader=httpConnection.getHeaderFieldKey(i); 0!D,74r  
if(sHeader!=null) L[]*vj   
{ F:PaVr3q  
if(sHeader.equals("Content-Length")) 7,i}M  
{ *wgHa6?+7  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Q}KNtNCpx  
break; 5E~?hWAv  
} Dq#/Uw#  
} sr0.4VU1  
else F{#m~4O  
break; LQ,RQ
~!  
} dLtSa\2Hn  
} +E8Itb,  
catch(IOException e){e.printStackTrace ();} 4"OUmh9LHB  
catch(Exception e){e.printStackTrace ();} Yy 4EM  
-BY'E$]4  
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Utility.log(nFileLength); 0_}^IiG  
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return nFileLength; `EV"
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} a@|/D\C  
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//保存下载信息（文件指针位置） L<kIzB !  
private void write_nPos() e&Z\hZBb  
{ T;cyU9  
try{ Wq bfZx  
output = new DataOutputStream(new FileOutputStream(tmpFile)); g/)$-Z)Nu  
output.writeInt(nStartPos.length); }PZz(Ms  
for(int i=0;i<nStartPos.length;i++) HT]v S}s  
{ L53qQej<  
// output.writeLong(nPos); Q^^.@FU"x  
output.writeLong(fileSplitterFetch.nStartPos); \5+?
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output.writeLong(fileSplitterFetch.nEndPos); _
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} }pE8G#O&  
output.close(); \htL\m^$9  
} 'C l}IDF  
catch(IOException e){e.printStackTrace ();} }E01B_T9z  
catch(Exception e){e.printStackTrace ();} XA cpLj]  
} ep"YGx  
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//读取保存的下载信息（文件指针位置） 0-)D`s%  
private void read_nPos() $ae*3L>5M  
{ b.qp&2A  
try{ nI1DLVt  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); _3q%  
int nCount = input.readInt(); h[5<S&  
nStartPos = new long[nCount]; KY)rkfo B  
nEndPos = new long[nCount]; "3!!G=s P  
for(int i=0;i<nStartPos.length;i++) M7Pvc%\)  
{ VZOf|o  
nStartPos = input.readLong(); R3MbTg  
nEndPos = input.readLong(); o8!gV/oy  
} QN%w\JXS  
input.close(); ?/mkFDN  
} *.
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catch(IOException e){e.printStackTrace ();} (S:+#v  
catch(Exception e){e.printStackTrace ();} G;:D6\  
} ^y@RfM=A  
\
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]!>ThBMa  
private void processErrorCode(int nErrorCode) ~|j:xM(i  
{ 9NH"Ik*  
System.err.println("Error Code : " + nErrorCode); 6E9y[ %+  
} )P6n,\  

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'xNPy =#  
//停止文件下载 b\/:-][  
public void siteStop() SZOcFmC?  
{ %-~W|Y  
bStop = true; uV]4C^k;`[  
for(int i=0;i<nStartPos.length;i++) ,hj5.;
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fileSplitterFetch.splitterStop(); zVLv-U/=d  
?[4!2T,Ca  
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} U @Il:\I  
} [OI&_WIw  
//负责部分文件的抓取 7wt2|$Qz  
**FileSplitterFetch.java %21i#R`E  
*/ ,2F4S5F~rC  
package NetFox; 8^fkY'x  
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import java.io.*; .xtjB8gc  
import java.net.*; &9CKI/K:  
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public class FileSplitterFetch extends Thread { B,SH9,  
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String sURL; //File URL 1'5I]D ec  
long nStartPos; //File Snippet Start Position <B]\&  
long nEndPos; //File Snippet End Position &Mset^o  
int nThreadID; //Thread's ID Gt&x<  
boolean bDownOver = false; //Downing is over aqvt
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boolean bStop = false; //Stop identical >3H/~ Y  
FileAccessI fileAccessI = null; //File Access interface tuA
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*_<P%J  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException WA-` *m$v  
{ m`<Mzk.u<  
this.sURL = sURL; RUTlwT
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this.nStartPos = nStart;
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this.nEndPos = nEnd; t#+X*'/  
nThreadID = id; R5LzqT,/N:  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 15Vb`Vf`N  
} #C?
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|H67ny&K^&  
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public void run() 2e}${NZN  
{ -GkNA"2M[  
while(nStartPos < nEndPos && !bStop) ~L!*p0dS^  
{ 7@g8nv(p  
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try{ @Taj++ua  
URL url = new URL(sURL); )u7*YlU\I  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Wxl^f?I`:  
httpConnection.setRequestProperty("User-Agent","NetFox"); OE(H:^ZR  
String sProperty = "bytes="+nStartPos+"-"; o56_t{<  
httpConnection.setRequestProperty("RANGE",sProperty); Dc |!H{Yr  
Utility.log(sProperty); ]KGLJ~hm>  
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InputStream input = httpConnection.getInputStream(); daT[2M  
//logResponseHead(httpConnection); kBY54pl  
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!dfc1UjB  
byte[] b = new byte[1024]; \F%5TRoC  
int nRead; tE0DST/
  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) [h8j0Q@Q  
{ N=K|Nw  
nStartPos += fileAccessI.write(b,0,nRead); v*%#Fp,g8  
//if(nThreadID == 1) -k{n"9a9?  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); .s31D%N  
} CW k#Amt.  
.3Nd[+[  
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Utility.log("Thread " + nThreadID + " is over!"); 7<[p1C*B  
bDownOver = true; o+W5xHe^1  
//nPos = fileAccessI.write (b,0,nRead); ]=p@1  
} :.['e
`  
catch(Exception e){e.printStackTrace ();} ^Yei9bXl  
} 0bxB@(NO  
} 3X$)cZQ  
.$+]N[-=  
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//打印回应的头信息 uhL+bj+W  
public void logResponseHead(HttpURLConnection con) <@FOqi{o{  
{ <Vyv)#32o3  
for(int i=1;;i++) orn9;|8q  
{
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String header=con.getHeaderFieldKey(i); ;crQ7}k  
if(header!=null) ;bVC7D~~4w  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ig:/60Z  
Utility.log(header+" : "+con.getHeaderField(header)); f3e#.jan  
else ((A]FOIbO  
break; Ev;HV}G  
} k"|4 LPv[  
} J#B% #X  
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public void splitterStop() >*H>'O4  
{ R6~x!  
bStop = true; Pw/Z;N;:V  
} +MPM^m  
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} }l&Uh&B`  
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J&}/Xw)  
/* Pl<r*d)h  
**FileAccess.java  6\ /x  
*//文件访问(定位，写) ~H/|J^ J  
package NetFox; yiGq?WA7  
import java.io.*; naCPSsei  
2bxkZS]  
U>6MT@\  
public class FileAccessI implements Serializable{ tVd\r"0k  
2yR*<yj  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 5Z}]d@  
RandomAccessFile oSavedFile; SCE5|3j  
long nPos; -}0S%|#m  
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public FileAccessI() throws IOException ARAC'F0  
{ FR9qW$B
  
this("",0); R%o:'-~  
} AEx I!  
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public FileAccessI(String sName,long nPos) throws IOException `E>HpRcxD  
{ L<!}!v5ja  
oSavedFile = new RandomAccessFile(sName,"rw"); :#58m0YLA:  
this.nPos = nPos; Xn-GSW3{  
oSavedFile.seek(nPos); \y^Od7F  
} F+Rto
q|  
8*3o9$Pj  
pDb5t>  
public synchronized int write(byte[] b,int nStart,int nLen) 'gk.J  
{ B PTQm4TN  
int n = -1; W-q2|N
K  
try{ G$pTTT6#  
oSavedFile.write(b,nStart,nLen); $,q~q^0  
n = nLen; Htn=h~
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} ,~8:^*0s  
catch(IOException e) !/+ZKx("9  
{ 
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e.printStackTrace (); q\ FF)H  
} ES!$JWK|  
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=3OK3|  
return n; km2('t7?  
} ;LE4UOK  
Jm$.$B&I  
}]_/:KUt  
} aAZS^S4v  
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:  
l T~RH0L  
/* fyPpzA0  
**SiteInfoBean.java ^I03PIy0l  
*/ 9Z]~c^UB  
package NetFox; o&P}GcEIw  
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public class SiteInfoBean { :+{G|goZ*  
z+I'N4*^  
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private String sSiteURL; //Site's URL 
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private String sFilePath; //Saved File's Path ~Q"3#4l  
private String sFileName; //Saved File's Name Bz<
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private int nSplitter; //Count of Splited Downloading File C,7d  
GL$!JKWp  
0X@!i3eu  
public SiteInfoBean() j78WPG  
{//nSplitter的缺省值为5 &v|Uy}h&%1  
//default value of nSplitter is 5 =!T@'P?  
this("","","",5); !E!i`yF  
} DhY.5  
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I Y%M5
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) n2&*5m&$  
{ i'9aQi"G  
sSiteURL= sURL; DhZuQpH
 
sFilePath = sPath; VZo[\sWf  
sFileName = sName; ,Oa-AF/p  
this.nSplitter = nSpiltter; stuj,8  
>QO^h<.>  
)3#gpM  
} Fw5|_@&k  
_+PiaJ&'  
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public String getSSiteURL() ?q a  
{ '
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return sSiteURL; K ;\~otR^  
} 2Ya)I k{  
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public void setSSiteURL(String value) TI4#A E  
{ ,5oe8\uz  
sSiteURL = value; "1O!Ck_n  
} {$D[l hj  
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MB.\G.bV  
public String getSFilePath() &_Kb;UVRj  
{ j6v|D>I  
return sFilePath; -!MrG68  
} FjRt'  
/(IV+  
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public void setSFilePath(String value) G8=2=/ !  
{ e??tp]PLn  
sFilePath = value; ~C[p}MED  
}  gGF]Dq  
p3>(ZWPNV  
n%'M?o]DF  
public String getSFileName() TNe
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{ Z9X<W`  
return sFileName; MzjV>.  
} D![42H+-Qd  
!5,>[^y3  
|^fubQs;2  
public void setSFileName(String value) <xM$^r)  
{ DfYOGs]@  
sFileName = value; 3ARvSz@5  
} Gk_%WY*  
,=sbK?&  
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public int getNSplitter() q#LB 2M  
{ >[t0a"  
return nSplitter; ^u'hl$`^  
} W0e+yIaR  
$VEG1]/svp  
_|<kKfd?  
public void setNSplitter(int nCount) l-s%3E3  
{ PP
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nSplitter = nCount; k=;>*:D%  
} ;:<z hO  
} |;xm-AM4r  
)Z6bMAb0'N  
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/* TljN!nv]  
**Utility.java *u LOoq  
*/ k(hYNmmo j  
package NetFox; HIiMq'H^  
#a1zk\R3  
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public class Utility { 590.mCm  
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m]H[$Q  
public Utility() OAigq6[,  
{
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x)evjX=q  
A8,9^cQ]  
} M)v\7a  
++O L&n  
//线程睡眠 OJ#ehw<  
public static void sleep(int nSecond) j,<3[  
{ W,sU5sjA  
try{ V
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Thread.sleep(nSecond); +'fy%/  
} wVegr  
catch(Exception e) 0|6]ps4Z7  
{ ~K'e}<-G  
e.printStackTrace (); feJzX*u  
} 9Z?P/ o  
} M:t!g%  
l^`& Tnzv  
//日志 `Fn"%P!  
public static void log(String sMsg) { 'A`ram  
{ 'iQ
  
System.err.println(sMsg); b\6)whh  
} L'i0|_  
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Q?"o
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public static void log(int sMsg) IZ
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{ 99QMMup  
System.err.println(sMsg); !LGnh  
} ku2gFO  
} yf|,/{S  
!Cqm=q{K  
Wp2W:JX:  
/* @|I:A  
**TestMethod.java R$>]7-N}  
*/ @ P:b\WCI  
package NetFox; IE;Fu67wi  
{;:QY1QT  
48}L!m @  
public class TestMethod { .&z/p3 1  
,E7+Z' ;  
(tZ#EL0  
public TestMethod() l'yX_`*Iq  
{ ///xx/weblogic60b2_win.exe :+ASZE.  
try{ U2Uf69R  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); $O
\I9CGr$  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); B#o/3  
SiteFileFetch fileFetch = new SiteFileFetch(bean); tKr.{#)  
fileFetch.start(); .`I;qF  
} 'eM90I%(  
catch(Exception e){e.printStackTrace ();} L&D+0p^lI  
P<. TiF?@  
T/[8w  
} xXa* d  
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xg:r5Z/|)  
public static void main(String[] args) 25bbuhss  
{ D\~s$.6B  
new TestMethod(); ;N+ v x  
} {J aulg  
} ?nVwT[  
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