http断点续传简单实现（java)

/* S4qj}`$ Yv  
**SiteFileFetch.java MJxTzQE  
*/ 9t`   
package NetFox; *C>B-j$  
import java.io.*; b ] W^_
 
import java.net.*; SiBhf3   
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public class SiteFileFetch extends Thread { 3>jL7sh%|  
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SiteInfoBean siteInfoBean = null; //文件信息Bean =SY5E{`4p  
long[] nStartPos; //开始位置 OB-2xmZW  
long[] nEndPos; //结束位置 yW3X<  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 X[F<sxw  
long nFileLength; //文件长度 XI>|"*-l  
boolean bFirst = true; //是否第一次取文件 
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boolean bStop = false; //停止标志 2d%j6D  
File tmpFile; //文件下载的临时信息 }
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DataOutputStream output; //输出到文件的输出流 .Fdqn?c|+  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） BPFd'-O)  
public SiteFileFetch(SiteInfoBean bean) throws IOException *TacVp  
{ zP[_ccW@  
siteInfoBean = bean; y1zNF$<q  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); W`$D*X0*o  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ?B&Z x-krd  
if(tmpFile.exists ()) !y1]S .;  
{ %FN3/iM
 
bFirst = false; t6zc$0-j"  
read_nPos(); *""JE'wG  
} \M@9#bd  
else CTqAhL 4}  
{ pH#*:v!)  
nStartPos = new long[bean.getNSplitter()]; yS*s[vT  
nEndPos = new long[bean.getNSplitter()]; p^=>N9  
} n9qO;X4&  
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} < C{-ph  
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public void run() OK=lp4X  
{ 8XwZJ\5  
//获得文件长度 "X\|!Mxh  
//分割文件 f^ q0#+k)  
//实例FileSplitterFetch $6&P 69<  
//启动FileSplitterFetch线程 @@
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//等待子线程返回 h"mG\xi  
try{ Y Me
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if(bFirst) +3@d]JfMh  
{ BE&P/~(C  
nFileLength = getFileSize(); I=N;F6  
if(nFileLength == -1) bu;3Ib3\  
{ XDtr{r6z  
System.err.println("File Length is not known!"); d+ LEi^  
} :'\4%D=w  
else if(nFileLength == -2) w&A&BE^O/  
{ ^qs{Cf$  
System.err.println("File is not access!"); )X8?m <cG  
}
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else W%/lBkP  
{ !11x&Db  
for(int i=0;i<nStartPos.length;i++) 50s)5G#  
{ F4!,8)}  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); {l/]+8G^  
} A5d(L4Q]a(  
for(int i=0;i<nEndPos.length-1;i++) /7EeM{,~  
{ 3YtFO;-  
nEndPos = nStartPos[i+1]; c5>'1L  
} iSm5k:7  
nEndPos[nEndPos.length-1] = nFileLength; mw^Di  
} $!+t2P@d.5  
} Fv[. %tW  
aJnZco6  
=cy;{2S'p  
//启动子线程 (thDv rT@2  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ?DAW~+,!7o  
for(int i=0;i<nStartPos.length;i++) c1v,5c6d j  
{ 1|_8+)i;  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Dv7/eRt  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), f8>S<:  
nStartPos,nEndPos,i); uYh6q1@"~  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); gk%8iT  
fileSplitterFetch.start(); 8,E#vQ55}(  
} d+9T}? T:*  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ,zCrix 3  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); u )'l|Y  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", l\vvM>#S  
nEndPos = " + nFileLength); nj
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// fileSplitterFetch[nPos.length-1].start(); Tk9/1C{8  
j( *;W}*^  
z0@)@4z!  
//等待子线程结束 /}~; b#t  
//int count = 0; 9fWr{fx  
//是否结束while循环 _g%Wx?K9  
boolean breakWhile = false; T>"GH M  
m?Gb5=qo  
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while(!bStop) ?V6+o`bm  
{ QlbhQkn  
write_nPos(); DYvi1X6  
Utility.sleep(500); (#w8/@JxF  
breakWhile = true; J- %YmUc)  
UOWOOdWSB  
*{5L*\AZ  
for(int i=0;i<nStartPos.length;i++) @2mJh^cj  
{ zTFfft
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if(!fileSplitterFetch.bDownOver) -0KQ
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{ *^'$YVd#  
breakWhile = false; _$OhV#LKG  
break; d|,,,+fS  
} jg ~;s  
} 3I)!.N[m  
if(breakWhile) 8]DN]\\o  
break; mp_
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//count++; 5 =Os sAr  
//if(count>4) yFt'<{z[nL  
// siteStop(); cZ(7/Pl  
} 0:(`t~  
_8Si8+j  
}2sc|K^  
System.err.println("文件下载结束！"); 8aCa(Xu(H  
} O5PCR6U  
catch(Exception e){e.printStackTrace ();} AHws5#;$6*  
} i!/V wGg  
C[j'0@~V:B  
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//获得文件长度 ;SBM
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public long getFileSize() Hv>C#U  
{ ^s@?\v  
int nFileLength = -1; 5S PGv}if  
try{ wW4/]soM  
URL url = new URL(siteInfoBean.getSSiteURL()); e+"rL]  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); opz.kP[e,  
httpConnection.setRequestProperty("User-Agent","NetFox"); H6<\7W89y  
\ H#zRSbZ  
}r&^*" 2=  
int responseCode=httpConnection.getResponseCode(); A9lnQCsJ  
if(responseCode>=400) T-=sC=sS,  
{ -I1Ne^DZn4  
processErrorCode(responseCode); 6&% c  
return -2; //-2 represent access is error .tB[8Y=J  
}
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String sHeader; KZn\ iwj  
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dq  
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for(int i=1;;i++) tzv&E0|d  
{ f=v+D0K$n  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); NQq$0<7.=W  
//Utility.log(in.readLine()); 6Lw34R  
sHeader=httpConnection.getHeaderFieldKey(i); JLT^0wBB  
if(sHeader!=null) i(q%E
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{ ]}/LNO*L"  
if(sHeader.equals("Content-Length")) q#Y%Y  
{ ^ N]u  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); sygAEL;.  
break; 7O{c>@\  
} %WrUu|xj>_  
} l -~HY*  
else C?Dztkz  
break; g7k|Ho-W  
} R9gK>}>Y  
} t?9F2rh  
catch(IOException e){e.printStackTrace ();} sfez0Uqe.~  
catch(Exception e){e.printStackTrace ();} )*N]Q  
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Utility.log(nFileLength); wmFI?   
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8>G3KZ3  
return nFileLength; bH+p5Fd;  
} AW@I,  
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//保存下载信息（文件指针位置） w">XI)*z  
private void write_nPos() ^-T!(P:  
{ Klh7&HzR  
try{ m4(
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output = new DataOutputStream(new FileOutputStream(tmpFile)); '7Dg+a^x7  
output.writeInt(nStartPos.length); +DS_'Tmr  
for(int i=0;i<nStartPos.length;i++) epi{Ayb  
{ *M;!{)m?  
// output.writeLong(nPos); -~eNC^t;W  
output.writeLong(fileSplitterFetch.nStartPos); !+&"y K@J  
output.writeLong(fileSplitterFetch.nEndPos); :0ZFbIy  
} uArs[e|f  
output.close(); zYfn;s%A  
} W:8_S%~d  
catch(IOException e){e.printStackTrace ();} W0eb9g`s  
catch(Exception e){e.printStackTrace ();} ~}|)@,N'bm  
} $6 \v1
 
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//读取保存的下载信息（文件指针位置） 7{j9vl6  
private void read_nPos() +`l>_u'  
{ SnVIV%  
try{ #(-V^T  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); u|ia  
int nCount = input.readInt(); xlF$PpRNM  
nStartPos = new long[nCount]; h9c54Ux  
nEndPos = new long[nCount];
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for(int i=0;i<nStartPos.length;i++) 8D[P*?O  
{ N~L3 9  
nStartPos = input.readLong(); 6rMGlzuRo  
nEndPos = input.readLong(); Be"D0=<  
} =mYY8c Yl  
input.close(); oqOv"yLJ:  
} |lAu6d !  
catch(IOException e){e.printStackTrace ();} \;&9h1?Mn  
catch(Exception e){e.printStackTrace ();} A1x?_S"a  
} j[Uul#  
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private void processErrorCode(int nErrorCode) a5C%OI<  
{ J3cbDE%^m  
System.err.println("Error Code : " + nErrorCode); P4"_qxAW  
} D%kY  
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MrEyN8X  
//停止文件下载  Ko9"mHNB  
public void siteStop() ]N!382  
{ *@|d7aiO  
bStop = true; IQxY]0\uf6  
for(int i=0;i<nStartPos.length;i++) %M^X>S\%  
fileSplitterFetch.splitterStop(); {tMpI\>S  
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} SU9qF73Y  
} ENm\1  
//负责部分文件的抓取 >t')ZSjRs  
**FileSplitterFetch.java @x?7J@:  
*/ #rM/  
package NetFox; ST1PSuC~  
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import java.io.*; c*$&MCh  
import java.net.*;  bz'V
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public class FileSplitterFetch extends Thread { i]!CH2\  
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String sURL; //File URL T:IKyb  
long nStartPos; //File Snippet Start Position -Wc'k 2oU  
long nEndPos; //File Snippet End Position 5xL%HX[S  
int nThreadID; //Thread's ID 5CH9m[S
 
boolean bDownOver = false; //Downing is over #jn6DL@[{  
boolean bStop = false; //Stop identical !7t,(Id8  
FileAccessI fileAccessI = null; //File Access interface ]}H;`H  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ?khwupdi  
{ CS2AKa@`  
this.sURL = sURL; qwJe
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this.nStartPos = nStart; 0G?0 Bo  
this.nEndPos = nEnd; /H&:  
nThreadID = id; )MqF~[k<-  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 @1ZLr  
} ?kvkkycI  
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public void run() +[M5x[[$  
{ ;|&Ak_I2G  
while(nStartPos < nEndPos && !bStop) _!6~o>  
{ OnFx8r:q@%  
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try{ !4 `any  
URL url = new URL(sURL); nf?;h!_7  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Cp(,+dD  
httpConnection.setRequestProperty("User-Agent","NetFox"); >:%YAR`  
String sProperty = "bytes="+nStartPos+"-"; 
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httpConnection.setRequestProperty("RANGE",sProperty); +O>1Ed  
Utility.log(sProperty); \hv1"WaJ  
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InputStream input = httpConnection.getInputStream(); +ew2+2  
//logResponseHead(httpConnection); pv8"E?9,k  
,!U5;  
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byte[] b = new byte[1024]; Vvu+gP'z.  
int nRead; A7SBm`XJ)p  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) "mr;|$Y  
{ i3g;B?54  
nStartPos += fileAccessI.write(b,0,nRead); TWE$@/9)g  
//if(nThreadID == 1) M6U/.
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// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ciO^2X  
} }XVz?6
  
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Utility.log("Thread " + nThreadID + " is over!"); ]>-#T  
bDownOver = true; %tiFx:F+  
//nPos = fileAccessI.write (b,0,nRead); HI6;=~[  
} (wLzkV/6  
catch(Exception e){e.printStackTrace ();} }<`Mn34@  
} 0Pw?@uV  
} =+`I%>wc  
{<%zcNKl^L  
|r_S2)zH9m  
//打印回应的头信息 1HK5OT&  
public void logResponseHead(HttpURLConnection con) ~_=ohb{  
{ >v^Bn|_/  
for(int i=1;;i++) j.OPDe{LU  
{ K
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String header=con.getHeaderFieldKey(i); -:wC920+  
if(header!=null) P<yd  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); \:ntqj&A|  
Utility.log(header+" : "+con.getHeaderField(header)); }TD$!  
else 7Fb |~In<Z  
break; tn};[r  
} K| #%u2C  
} CI$pPY<u1  
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public void splitterStop() 4{H>V_9zs  
{ J@'}lG  
bStop = true; sI
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} is_`UDaB  
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} E ?(+v  
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r J'm>&Ps  
/* vB(tpki|  
**FileAccess.java eED Fm  
*//文件访问(定位，写) aV`4M VWOz  
package NetFox; \v.16obH  
import java.io.*; o<2H~2/  
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public class FileAccessI implements Serializable{ J2VhheL`J  
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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 ^Z]1Z  
RandomAccessFile oSavedFile; $'!r/jV  
long nPos; Z'iXuI49  
}ybveZxv5A  
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public FileAccessI() throws IOException `h+ia/  
{ wlr/zquAE9  
this("",0); R:HF~}  
} sLh9=Kh`  
BhC.#u/   
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public FileAccessI(String sName,long nPos) throws IOException )HWf`;VQ  
{ @mM'V5
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oSavedFile = new RandomAccessFile(sName,"rw"); ek6PMZF:'  
this.nPos = nPos; 8*y
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oSavedFile.seek(nPos); yZFm<_9>  
} [U[saR\  
#xZ7%   
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public synchronized int write(byte[] b,int nStart,int nLen) 6c-y<J+&s  
{ j]i:~9xKW  
int n = -1; tEP~`$9  
try{ ;QbMVY  
oSavedFile.write(b,nStart,nLen);
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n = nLen; K
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} a&b75.-  
catch(IOException e) z$OKn#%T  
{ _r0[ z  
e.printStackTrace (); o!6gl]U'y9  
} @MMk=/WDw  
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return n; "{-jZdq'  
} *{|{T_H:  
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} A}KRXkB  
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/* |f+|OZY  
**SiteInfoBean.java W9>q1  
*/ $w{!}U2+-  
package NetFox; x#z}A&  
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public class SiteInfoBean { B[k {u#Kp  
 )!2$yD  
@C7iflo6  
private String sSiteURL; //Site's URL ht _fbh(l  
private String sFilePath; //Saved File's Path P)bS ;w\(Y  
private String sFileName; //Saved File's Name f4Aevh:  
private int nSplitter; //Count of Splited Downloading File uN1(l}z$  
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public SiteInfoBean() \]pRu"  
{//nSplitter的缺省值为5 ;ew j  
//default value of nSplitter is 5 <:=}1t.Z  
this("","","",5); B;f\H,/59  
} U_!Wg|  
Q _Yl:c  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) R$qp3I  
{ D90m..\w  
sSiteURL= sURL; =ZdP0l+V=k  
sFilePath = sPath; 7!.#:+rg5#  
sFileName = sName; QR4!r@*=  
this.nSplitter = nSpiltter; LliOhr4  
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} [7d>c  
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public String getSSiteURL() 4LY kK/:  
{ 8%-+@\=  
return sSiteURL; KI&+Zw4VL  
} SymBb}5  
bF'Y.+"dr  
pU4k/v555;  
public void setSSiteURL(String value) VKUoVOFvPR  
{ &3a1(>(7F  
sSiteURL = value; ico%_fp  
} xb`,9.a7  
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public String getSFilePath() 09FHE/L  
{ ~dkN`
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return sFilePath; %mLQ'$  
} =
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public void setSFilePath(String value) lP$bxUNt  
{ Q4;
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sFilePath = value; >^mNIfdE^=  
} !ho~@sc{W  
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public String getSFileName() ySC;;k
'  
{ )tc"4lp-  
return sFileName; >(N0''eM]  
} khSb|mR)  
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.9r+LA{  
public void setSFileName(String value) ;IklS*p]  
{ V5
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sFileName = value; <HReh>)[  
} jSLC L'  
+n#(QOz  
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public int getNSplitter() IB~`Ht8 b  
{ uL`6}0  
return nSplitter; Cso!VdCX  
} s{IXth6  
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public void setNSplitter(int nCount) Vn:BasS%  
{
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nSplitter = nCount; xc|pl!ns  
} \_H-TbU8  
} ,:RHhg  
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/* RPH]@  
**Utility.java iR k
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*/ \?n4d#=$o  
package NetFox; -Fi{[%&u  
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public class Utility { vn5X]U"  
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public Utility() Jptzc:~B  
{ B.:DW3  
dy>iIc>  
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} 014p= W  
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//线程睡眠 g[Tl#X7F  
public static void sleep(int nSecond) sY @S  
{ ohI>\  
try{ WD"3W)!  
Thread.sleep(nSecond); 5f.G^A: _X  
} )e,Rp\fY$  
catch(Exception e) m6V:x/'=  
{ +kh#J
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e.printStackTrace (); l`#XB:#U  
} z:Sr@!DZ  
} %cy]dEL7  
b{:
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//日志 z:m`  
public static void log(String sMsg) UkO
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{ 4Ji6B)B  
System.err.println(sMsg); ym>>5(bni  
} XaFu(Xu7  
>.P/fnvJ  
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public static void log(int sMsg) *k&yD3br-V  
{ @fDWp/  
System.err.println(sMsg); os=Pr{  
} ifo^ M]v  
} *-KgU'u?  
cmw2EHTT<  
mkJC*45  
/* B@R3j  
**TestMethod.java 1e Wl:S}  
*/ `RRC8]l  
package NetFox; #LP38wE  
KY1(yni&8[  
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public class TestMethod { aT v  
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LyEM^d]  
public TestMethod() .}AzkKdd@  
{ ///xx/weblogic60b2_win.exe ~;m3i3D  
try{ ^TC<_]7  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); UODbT&&  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); +/">]QJ  
SiteFileFetch fileFetch = new SiteFileFetch(bean);
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fileFetch.start(); jacp':T  
} Dgb@

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catch(Exception e){e.printStackTrace ();} *2K/)(  
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ba=-
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} iX3Y:   
gBF2.{"^  
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public static void main(String[] args) fjc8@S5x9j  
{ AKKp-I5  
new TestMethod(); jm|x=s3}h  
} --(e(tvf  
} jgc
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