http断点续传简单实现（java)

/* .K`OEdr<  
**SiteFileFetch.java 3sG7G:4  
*/ ! |SPOk  
package NetFox; )"k>}&'  
import java.io.*; Q#C;4)e  
import java.net.*; &:}e`u@5|  
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public class SiteFileFetch extends Thread { T}} 0hs;  
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SiteInfoBean siteInfoBean = null; //文件信息Bean W>C!V  
long[] nStartPos; //开始位置 pR_cI]{=SA  
long[] nEndPos; //结束位置 we'<Y  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 nQ|4.e;  
long nFileLength; //文件长度 %Q]u_0P
*  
boolean bFirst = true; //是否第一次取文件 &<I*;z6%t  
boolean bStop = false; //停止标志 y,qP$5xiq  
File tmpFile; //文件下载的临时信息 >!+.M9  
DataOutputStream output; //输出到文件的输出流 Y.I-hl1<r  
 !sda6?&  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） a<X8l^Ln  
public SiteFileFetch(SiteInfoBean bean) throws IOException &gJKJ=7  
{ z;1y7W!v  
siteInfoBean = bean; y*2R#jTA  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); OJd!g/V  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Zgp]s+%E  
if(tmpFile.exists ()) ""Ul6hRgv  
{ 8 vNgePn  
bFirst = false; 1-Fg_G}|6  
read_nPos(); nb(4"|8}  
} Z09FW>"u  
else `(A6uakd  
{
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nStartPos = new long[bean.getNSplitter()]; M=[/v/M=  
nEndPos = new long[bean.getNSplitter()]; j]7|5mC78  
} 1xK'1g72  
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} pT]M]/y/:  
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public void run() ".L+gn}u-  
{ -Nmf}`_  
//获得文件长度 WO*yJ`9]  
//分割文件 n
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//实例FileSplitterFetch 2>Kq)Ii  
//启动FileSplitterFetch线程 _dqjRhu  
//等待子线程返回 &QE^i%6>\  
try{ R#~}ZUk2  
if(bFirst) !s,<hU#  
{ etf ft8  
nFileLength = getFileSize(); tYIHsm\b  
if(nFileLength == -1) ~C5iyXR  
{ x6HebIR+  
System.err.println("File Length is not known!"); cb&y8!ci~  
}
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else if(nFileLength == -2) (Wr;:3i  
{ %9M; MK  
System.err.println("File is not access!"); Z{#^lhHx  
} pALB[;9g  
else EC1q#;:  
{ bI[!y#_z4  
for(int i=0;i<nStartPos.length;i++) fLI@;*hL0  
{ 7qE V5!  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); {EJVZG:&  
} }=A6Jv(j  
for(int i=0;i<nEndPos.length-1;i++) |UnTd$m  
{ +azPpGZ=  
nEndPos = nStartPos[i+1]; m?<8 ':  
} =)M8>>l  
nEndPos[nEndPos.length-1] = nFileLength; 6AU
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} {\|? {8f  
} L:Wy- Z  
;YZw{|gsh  
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//启动子线程 HKOJkbVZ2^  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; IX7d[nm39  
for(int i=0;i<nStartPos.length;i++) 1)_f9GR  
{ I-/PzL<W P  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ^%_B'X9  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 9Z*`{  
nStartPos,nEndPos,i); S-2xe?sb  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); |Q9S$l]  
fileSplitterFetch.start(); `m2F.^qrr  
} {(a@3m~a%  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), b@YSrjJ  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); .6O>P2m]a_  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", O.rk!&N  
nEndPos = " + nFileLength); qgZ(o@\  
// fileSplitterFetch[nPos.length-1].start(); q<c).
4  
9q* sR1  
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//等待子线程结束 2gt08\  
//int count = 0; #S<>+,Lk  
//是否结束while循环 GQF7]j/  
boolean breakWhile = false; K:'pK1zy  
,?&hqM\  
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while(!bStop) )_j.0a  
{ t9m`K9.\  
write_nPos(); K?I@'B'  
Utility.sleep(500); _"WQi}
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breakWhile = true; AO']Kmm  
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for(int i=0;i<nStartPos.length;i++) ?Fi-,4  
{ 8 6L&u:o:  
if(!fileSplitterFetch.bDownOver) <S\S @3  
{ :~T:&;q0  
breakWhile = false; 8kMMQES  
break; R1P,0Yf  
} !5A nr  
} %{}Jr`
 
if(breakWhile) R4IFl z  
break; =_ rn8  
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//count++; 3Ji,n;QLm  
//if(count>4) 
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// siteStop(); @L
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} vxqMo9T  
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System.err.println("文件下载结束！"); 5n9F\T5  
} wV-cpJ,}  
catch(Exception e){e.printStackTrace ();} _&dGo(B  
} 'm2,7]  
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//获得文件长度 ZnJnjW PQ  
public long getFileSize()
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{ JGO>X|T  
int nFileLength = -1; LZoth+:  
try{ rBny*!n  
URL url = new URL(siteInfoBean.getSSiteURL()); Ab(bvS8r$  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Y/$SriC_+'  
httpConnection.setRequestProperty("User-Agent","NetFox"); F8=6!Qj  
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int responseCode=httpConnection.getResponseCode(); ,U7hzBj8k  
if(responseCode>=400) 3[e@mcO  
{ ;ib~c,  
processErrorCode(responseCode); ?&X6VNbU  
return -2; //-2 represent access is error #JW1JCT  
} P{qn@:  
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String sHeader; DX!$k[  
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for(int i=1;;i++) t6"4+:c!>  
{ &G"]v]V  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); -#i%4[v  
//Utility.log(in.readLine()); nut7b  
sHeader=httpConnection.getHeaderFieldKey(i); K3Xy%pqR#  
if(sHeader!=null)  (&gCVf  
{ un/eS-IIh  
if(sHeader.equals("Content-Length")) N&ddO-r[s  
{ (%r:PcGMEV  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); zeua`j
Q  
break; sV+>(c-$  
} ^Gyl:hN  
} <B fwR$  
else FE5R ^W#u-  
break; 6S&#8l  
} [Dt\E4  
} %EpK=;51U  
catch(IOException e){e.printStackTrace ();} tT v@8f  
catch(Exception e){e.printStackTrace ();} vd;wQ  
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Utility.log(nFileLength); >:xnjEsi$/  

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return nFileLength; q{@Wn]!k  
} '|cuVxcE55  
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iIT<{m&`  
//保存下载信息（文件指针位置） j[HKC0C6  
private void write_nPos() p<+]+,|\~:  
{ X-duG*~  
try{ d-*9tit  
output = new DataOutputStream(new FileOutputStream(tmpFile)); OYzJE@r^  
output.writeInt(nStartPos.length); lAGxE-B^a"  
for(int i=0;i<nStartPos.length;i++) .dfTv/n  
{ ::R^ w"  
// output.writeLong(nPos); b'&pJ1]]}  
output.writeLong(fileSplitterFetch.nStartPos); }Q%>Fv  
output.writeLong(fileSplitterFetch.nEndPos); :.~a[\C@V<  
} 2iGRw4`_a  
output.close(); _5)#{o<  
} ~U1iB  
catch(IOException e){e.printStackTrace ();} F>M$|Sc2  
catch(Exception e){e.printStackTrace ();} XXF9oy8  
} a_ P[J8j  
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//读取保存的下载信息（文件指针位置） 7Y)wu$!7}  
private void read_nPos() j@ "`!uPz  
{ wv7jh~x(4  
try{ OBl8kH(b>  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Y1~SGg7(@  
int nCount = input.readInt(); V;6M[ic}  
nStartPos = new long[nCount]; WNx^Rg" >'  
nEndPos = new long[nCount]; UVLcR  
for(int i=0;i<nStartPos.length;i++) !G,$:t1-=V  
{ (HF,p,h_  
nStartPos = input.readLong(); "tark'  
nEndPos = input.readLong(); PHXP1)^}S  
} HB}gn2.1&  
input.close(); |x4yPYBL  
} sHuz10  
catch(IOException e){e.printStackTrace ();} D6]$P%t9  
catch(Exception e){e.printStackTrace ();} @r43F$bcqo  
} 5 QeGx3'  
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private void processErrorCode(int nErrorCode) b>z.d-  
{ z]YhQIU4n8  
System.err.println("Error Code : " + nErrorCode); gh}AD1TN]  
} L1xD$wl  
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OW}A48X[+  
//停止文件下载 "{k )nr+7U  
public void siteStop() 9O Q4\  
{ ZX;k*OrW  
bStop = true; =QfKDA  
for(int i=0;i<nStartPos.length;i++) {|h"/  
fileSplitterFetch.splitterStop(); h%s  
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} O-5U|wA  
} [8P2V  
//负责部分文件的抓取 Q7
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**FileSplitterFetch.java WS/+Yl  
*/ +I n"OR%  
package NetFox; \Ji2uGT  
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import java.io.*; *`-29eR"8  
import java.net.*; d-sh
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public class FileSplitterFetch extends Thread { $tHwJ!<$&  
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String sURL; //File URL p.] .M"A  
long nStartPos; //File Snippet Start Position %QgAilj,  
long nEndPos; //File Snippet End Position Sc$wR{W<:
 
int nThreadID; //Thread's ID #ljg2:I+  
boolean bDownOver = false; //Downing is over Qf>Pb$c$U  
boolean bStop = false; //Stop identical FqxOHovE  
FileAccessI fileAccessI = null; //File Access interface ,M&0<k\  
}!<cph  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 25c!-.5D  
{ +4g%?5'  
this.sURL = sURL; <1+6O[>{  
this.nStartPos = nStart; F]A~~P  
this.nEndPos = nEnd; 7 eQoc2X2  
nThreadID = id; m'(;uR`  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 6q[!X0u  
} `ab\i`g9  
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public void run() kqvJ&7  
{ FT/5 _1i  
while(nStartPos < nEndPos && !bStop) if[o?6U4t  
{ >_aio4j}r  
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try{ U?F^D4CV\  
URL url = new URL(sURL); #f3;}1(  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); bjPbl2K  
httpConnection.setRequestProperty("User-Agent","NetFox"); -iDEh_pts  
String sProperty = "bytes="+nStartPos+"-"; NC.P2^%  
httpConnection.setRequestProperty("RANGE",sProperty); EdAR<VfleA  
Utility.log(sProperty); }\939Y  
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InputStream input = httpConnection.getInputStream(); X`3vSCn  
//logResponseHead(httpConnection); ,B~lwF9  
h lkvk]v  
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byte[] b = new byte[1024]; ,|.*,  
int nRead; BgkB x  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) |)?aH2IL  
{ ZcTL#OTP  
nStartPos += fileAccessI.write(b,0,nRead); ]]uzl0LH  
//if(nThreadID == 1) HZDaV&)@  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); B)"#/@!bHH  
} ].-J.  
[-E{}FL|  
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Utility.log("Thread " + nThreadID + " is over!"); 6MQs \J6.  
bDownOver = true; XSp x''l  
//nPos = fileAccessI.write (b,0,nRead); QtnM(m  
} <84C tv  
catch(Exception e){e.printStackTrace ();} /lr1hW~Dbk  
} {UdcX~\~  
} xTJSr2f  
*>aZc::  
>[|GC/
C  
//打印回应的头信息 L}}=yh6r  
public void logResponseHead(HttpURLConnection con) i
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{ {d1N&  
for(int i=1;;i++) H@%7\g,`  
{ R=vbUA  
String header=con.getHeaderFieldKey(i); 8h&oSOkQk,  
if(header!=null) 9h:jFhsA9  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); c<=`<!FS[  
Utility.log(header+" : "+con.getHeaderField(header)); dThR)Z'=  
else Rwc[:6;fn  
break; Q7~'![(a  
} t7um [  
} v8=?HUDd  
{D_++^  
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public void splitterStop() pqyWv;  
{ .'t (-eT,  
bStop = true; :3KO6/+  
} 6=ZRn gQ  
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} = n+q_.A  
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/* 5f;n<EPy  
**FileAccess.java
&$mZ?%^C  
*//文件访问(定位，写) yGba  
package NetFox; 2y3?!
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import java.io.*; 0JmFQ^g(  
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public class FileAccessI implements Serializable{ J.1O/Pw!.a  
<RhOjZgyZ  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 To3^L_v"
 
RandomAccessFile oSavedFile; CQ@LmTW[  
long nPos; &MCy.(jN  
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public FileAccessI() throws IOException <^d!Vzr]  
{ ^'m\D;
 
this("",0); TqIAWbb&  
} Z:K+I+:t  
*i@sUM?K  
%1Yz'AiW[  
public FileAccessI(String sName,long nPos) throws IOException k/%#>  
{ kW#S]fsfU  
oSavedFile = new RandomAccessFile(sName,"rw"); r]v&t  
this.nPos = nPos; !_qskDc-  
oSavedFile.seek(nPos); xpF](>LC(  
} e|yX QTlvL  
v2d<o[[C  
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public synchronized int write(byte[] b,int nStart,int nLen) (B@X[
~  
{ ^V[/(Lq  
int n = -1; d^PD#&"g  
try{ 1Q]Rd  
oSavedFile.write(b,nStart,nLen); )B6
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n = nLen; cv2]*  
} ',GV6kt_k  
catch(IOException e) @
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{ u#1%P5r&X  
e.printStackTrace (); +=7:4LFOL  
} _g[-=y{Bb  
y,Jh@n';|  
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return n; {(4# )K2g%  
} (?vK_{  
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} /be=u@KV  
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/* +c--&tBo  
**SiteInfoBean.java \@K
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*/ 3H
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package NetFox; ;\qXbL7  
 Hy]  
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public class SiteInfoBean { -p`L%xj\  
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private String sSiteURL; //Site's URL :'}@Al9=>  
private String sFilePath; //Saved File's Path _\\ -md:  
private String sFileName; //Saved File's Name RP! X8~8  
private int nSplitter; //Count of Splited Downloading File %?9Ok  
:_xh(W+2<  
oZN'HT  
public SiteInfoBean() /1d<P! H  
{//nSplitter的缺省值为5 [}-3PpF  
//default value of nSplitter is 5 jAC78n,Fi@  
this("","","",5); W\8Ln>  
} BtsdeLj|  
+Rwx%=  
e)@3m.  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 7&U&E|  
{ Y/fJQ6DY  
sSiteURL= sURL; w<NyV8-hL  
sFilePath = sPath; .Q* 'r&n  
sFileName = sName; U]R~gy}#  
this.nSplitter = nSpiltter; =sgdkAYwP  
rjk( X|R*  
0 )}$^TV  
} /Vww?9U;  
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public String getSSiteURL() s^hR\iY  
{ iPj~I  
return sSiteURL; }^%xvmQ\]  
} eSfnB_@x2  
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28I^$> [  
public void setSSiteURL(String value) h4)Bs\==mT  
{ w0lT%CPx  
sSiteURL = value; `@Oa lg  
} `<frgXu64  
F<|t\KOW  
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public String getSFilePath() vFv3'b$;G  
{ i=S~(gp  
return sFilePath; p3(2?UO!  
} cU.9}-)  
vB'>[jvA|  
'b&yrBFD  
public void setSFilePath(String value) ?C-Towo=i  
{ u<xo/=Z  
sFilePath = value; E_T2z4lw  
} neZ.`"LV  
}baR5v  
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public String getSFileName() `G9 l  
{ iUi>y.}"P  
return sFileName; hX:"QXx  
} }H> ^o9  
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public void setSFileName(String value) Z<?OwAWz  
{ sgUud_r)4  
sFileName = value; 2,q}Nq  
} $'rG-g!f\  
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public int getNSplitter() ia
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{ :rMM4  
return nSplitter; Zdc63fllM  
} Pz*_)N}j >  
dP?Ge}  
b?X.U}62_  
public void setNSplitter(int nCount) u$#Wv2|mk  
{ pKiZ)3U  
nSplitter = nCount; F
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} ~}EMk3  
} GPz(j'jU  
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/* JxE53ev  
**Utility.java ]V l]XT$Um  
*/ t7n(Qkrv  
package NetFox; nRL. ppUI  
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public class Utility { X+L) -d  
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g
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public Utility() ('wY9kvL&  
{ [[PEa-992  
IG)s^bP  
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} ];'v8
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`>0MNmu  
//线程睡眠 NH$r Z7$  
public static void sleep(int nSecond) JD@J[YY5R  
{ kB?al#`  
try{ &j(+/;A  
Thread.sleep(nSecond); d ;vT ~;  
} \
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catch(Exception e)
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{ MZ Aij  
e.printStackTrace (); 3"o"fl  
} (Yp+bS(PU*  
}
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x77l~=P+!  
//日志 !x!07`+^u  
public static void log(String sMsg) 64hk2a8  
{ :'#TCDlOb  
System.err.println(sMsg); K>*a*[t0Sy  
} ,%\o4Rc'o  
:0s]U_
h  
=Umw$+fJr  
public static void log(int sMsg) O_Oj|'bBC  
{ v)
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System.err.println(sMsg); TMYd47  
} `rf_7  
} z dO#0tN  
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@|Rrf*J?%  
/* M5xCC!  
**TestMethod.java 5 ~TdD6}  
*/ um9_ru~  
package NetFox; _i/t?7  
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H^YSJ6  
public class TestMethod { ]c! ;L5
 
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=$]uoA  
public TestMethod() hWX% 66  
{ ///xx/weblogic60b2_win.exe _q~=~nub  
try{ m=YU2!Mb  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); _cXqAo  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); $m42:amM  
SiteFileFetch fileFetch = new SiteFileFetch(bean); OF\rgz
 
fileFetch.start(); ?M[ A7?  
} :_O%/k1\@  
catch(Exception e){e.printStackTrace ();} k{'0[,mx#  
Y.*y9)#S6  
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} j$+nKc$  
7}X[ 4("bB  
t+eVR8  
public static void main(String[] args) 2$Tj84'X  
{ Z,=7Tu bR#  
new TestMethod(); }mAa}{_  
} /n>qCuw  
} ,lyb!k8  
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