http断点续传简单实现（java)

/* I>8_gp\1  
**SiteFileFetch.java }S*]#jr&  
*/ BJ_"FG  
package NetFox; :/gHqEC24  
import java.io.*; (-J'x%2)  
import java.net.*; +b_[JP2  
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public class SiteFileFetch extends Thread { N*[b26  
 O,7S1  
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SiteInfoBean siteInfoBean = null; //文件信息Bean u[SqZftmO  
long[] nStartPos; //开始位置 u-jV@Tz  
long[] nEndPos; //结束位置 w3VgGc~  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 *oLDy1<  
long nFileLength; //文件长度 |oOAy  
boolean bFirst = true; //是否第一次取文件 ,yp#!gE~  
boolean bStop = false; //停止标志 /j3",N+I  
File tmpFile; //文件下载的临时信息 8mOGEx  
DataOutputStream output; //输出到文件的输出流 k&L/JzzI  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） \HrtPm`e  
public SiteFileFetch(SiteInfoBean bean) throws IOException 8*Fn02 p  
{ "Uf1;;b  
siteInfoBean = bean; # bjK]+  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 
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tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); BK)<~I  
if(tmpFile.exists ()) }tBw<7fe  
{ :,yC\,H^  
bFirst = false; +BO kHXk1  
read_nPos(); XgXXBKf$  
} a*}>yad  
else SXe1Q8;  
{ FSz<R*2  
nStartPos = new long[bean.getNSplitter()]; $y.0h(  
nEndPos = new long[bean.getNSplitter()]; ,cS_687o  
} [+l
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} k{S8q?Gc  
@
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public void run() _iDVd2X"H  
{ O#):*II`9  
//获得文件长度  (~bx%  
//分割文件 \ q
q  
//实例FileSplitterFetch \Wg_ gA  
//启动FileSplitterFetch线程 z
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//等待子线程返回 8lDb<i  
try{ Sp?e!`|8  
if(bFirst) ~H   
{ cX4]ViXSr  
nFileLength = getFileSize(); :x5O1Zn/t  
if(nFileLength == -1) Ahba1\,N$  
{ 5D<ZtsXE  
System.err.println("File Length is not known!"); 4{vEW(  
} 3` oOoKX  
else if(nFileLength == -2) ux!YVvTPd  
{ hosY`"X  
System.err.println("File is not access!"); imzPVGCD{  
} mvTp,^1  
else z$~F9Es9  
{ $%'3w~h`  
for(int i=0;i<nStartPos.length;i++) '|yCDBu  
{ `jr?I {m;  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); <HN{.p{  
} %QGw`E   
for(int i=0;i<nEndPos.length-1;i++) >KdV]!H  
{ #pK" ^O*!  
nEndPos = nStartPos[i+1]; KUm?gFh  
} [eOv fD  
nEndPos[nEndPos.length-1] = nFileLength; E]m?R 4  
} wsH_pF  
} *TI?tD  
;b1B*B  
U~"Y8g#qgy  
//启动子线程 nf
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; |S|'o*u  
for(int i=0;i<nStartPos.length;i++) cL03V?} ~  
{ ]{\M,txo8  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), g*LD}`X/-  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), rcMf1\  
nStartPos,nEndPos,i); pz)>y&_o  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Q@NFfJJ  
fileSplitterFetch.start(); J>nBTY,_<  
} ) < U9  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), -<5{wQE;|  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); nu-&vX  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", d(ypFd9z  
nEndPos = " + nFileLength); b l+g7g;  
// fileSplitterFetch[nPos.length-1].start(); {]dtA&8(  
Ov?J"B'F  
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//等待子线程结束 vW vu&3tx  
//int count = 0; YC56]
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//是否结束while循环 xz5A[)N  
boolean breakWhile = false; 2E!~RjxSY  
2ag8?#  
3z2 OW@zL$  
while(!bStop) xb9+-{<J  
{ T:m" eD;  
write_nPos(); IVxZ.5:L$  
Utility.sleep(500); /"j3B\`?  
breakWhile = true; t
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,#&7+e!]>P  
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for(int i=0;i<nStartPos.length;i++) rZaO^}u]  
{ Pn[oo_)s  
if(!fileSplitterFetch.bDownOver) @v#P u_  
{ ^ W?cuJ8  
breakWhile = false; [x>Ju&))$  
break; |ll
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} uXh:/KO  
} lNa+NtQu  
if(breakWhile) wT::b V{  
break; *pS 7,Hm  
\P?X`]NwnO  
';/J-l/SE  
//count++; KbvMp1'9P  
//if(count>4) eJHh}  
// siteStop(); X V;j6g  
} wL 4Y%g  
Em@:QmEN  
0C/ZcfFU~  
System.err.println("文件下载结束！"); 0zq'Nf?#3  
}
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catch(Exception e){e.printStackTrace ();} 5j1d=h  
} Ws@'2i\;  
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//获得文件长度 F1L[3D^-  
public long getFileSize() @q/g%-WNz  
{ Q,xL8i M,  
int nFileLength = -1; E3wL n/<  
try{ p#ar`-vQ  
URL url = new URL(siteInfoBean.getSSiteURL()); A:r?#7 Ma  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); K -rR)-rI  
httpConnection.setRequestProperty("User-Agent","NetFox"); 6- i.*!I 8  
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_q27 3QG/"  
int responseCode=httpConnection.getResponseCode(); IL %]4,  
if(responseCode>=400) '|^:,@8P9  
{ #lLUBJ#:  
processErrorCode(responseCode); GYaP"3Lu  
return -2; //-2 represent access is error P6 OnE18n  
} 2Kz+COP+  
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p?rl
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String sHeader; &oS$<  
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for(int i=1;;i++) pD732L@q  
{ oY18a*_>M1  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Z nc(Q  
//Utility.log(in.readLine()); ~-BF7f6C  
sHeader=httpConnection.getHeaderFieldKey(i); ~y!'\d>q<  
if(sHeader!=null) )S)L9('IxT  
{ 3`HK^((o  
if(sHeader.equals("Content-Length")) aKbmj  
{ \WCQ>c?~  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); AC) M2;  
break; NXY jb(4:  
} _95296  
} M<fhQJ  
else BPba3G9H  
break; K T}  
} )|F|\6:ne  
} `C+<!)2  
catch(IOException e){e.printStackTrace ();} FRBu8WW0L  
catch(Exception e){e.printStackTrace ();} 86r5!@WN  
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Utility.log(nFileLength); 6Xlzdt  
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return nFileLength; 'YNaLZ20  
} =Ph8&l7~sp  
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p T(M>LP83  
//保存下载信息（文件指针位置） :S+K\  
private void write_nPos() M?$[WS  
{ ~&?bU]F  
try{ IHl q27O  
output = new DataOutputStream(new FileOutputStream(tmpFile)); d8j1L/e  
output.writeInt(nStartPos.length); }SN( ^3N  
for(int i=0;i<nStartPos.length;i++) f!Q\M1t)  
{ ;;Q^/rkC  
// output.writeLong(nPos); #WpkL]g2+%  
output.writeLong(fileSplitterFetch.nStartPos); AlSO  
output.writeLong(fileSplitterFetch.nEndPos); $B+|
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} ly[LF1t  
output.close(); )ZJvx%@i  
} 3FEJ 9ZyG  
catch(IOException e){e.printStackTrace ();} _FLEz|%~  
catch(Exception e){e.printStackTrace ();} ;?-AFd\i
 
} \oQ]=dDCd%  
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^URCnJ67Se  
//读取保存的下载信息（文件指针位置） GF'wDi}  
private void read_nPos() OZ,kz2SF#  
{ )?L=o0  
try{ pm&THd  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 3dShznlf_*  
int nCount = input.readInt(); iTVe8eI  
nStartPos = new long[nCount]; pJpapA2l*6  
nEndPos = new long[nCount]; "n-'?W!  
for(int i=0;i<nStartPos.length;i++) ^
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{ )s2] -n}W  
nStartPos = input.readLong(); yC,/R371k  
nEndPos = input.readLong(); bf3!|Um  
} K~x,so  
input.close(); |.IH4 K  
} wucdXj{%  
catch(IOException e){e.printStackTrace ();} 4JSPD#%f  
catch(Exception e){e.printStackTrace ();} kmuksT\)a  
} ^ k^y|\UtZ  
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private void processErrorCode(int nErrorCode) [}X|&`'i  
{ H#-3  
System.err.println("Error Code : " + nErrorCode); cpY{o^  
} $|4C]Me (  
=bC +1 C  
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//停止文件下载 <3YZ0f f>  
public void siteStop() >%JPgr/ 8  
{ D-3[#~MV  
bStop = true; R+sT &d  
for(int i=0;i<nStartPos.length;i++) ^\)a[OWp  
fileSplitterFetch.splitterStop(); &[.5@sv  
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} w7nt $L5  
} p:,Y6[gMo  
//负责部分文件的抓取 C \ Cc[v  
**FileSplitterFetch.java yTaMlT|  
*/ X/]@EF  
package NetFox; oL4W>b )  
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8$Q`wRt(%  
import java.io.*; lwnO  
import java.net.*; LyUn!zV$(  
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public class FileSplitterFetch extends Thread { jA? #!lx_  
(5a73%>@  
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String sURL; //File URL vr!J3H f  
long nStartPos; //File Snippet Start Position <Ij!x`MS+  
long nEndPos; //File Snippet End Position AXfU$~  
int nThreadID; //Thread's ID 6K2e]r  
boolean bDownOver = false; //Downing is over >WLPE6E  
boolean bStop = false; //Stop identical tMr7d  
FileAccessI fileAccessI = null; //File Access interface dQut8>0&  
=;Id["+  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException n `j._G  
{ 9rB3h`AVF  
this.sURL = sURL; *miG<  
this.nStartPos = nStart; gv!8' DKn  
this.nEndPos = nEnd; [hJ1]RW8  
nThreadID = id; !3Dq)ebBz  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 $Dg-;I  
} H7O~So*N5  
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public void run() 1-RY5R}VR  
{ F?L]D
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while(nStartPos < nEndPos && !bStop) u09Tlqh0 3  
{ _h%Jf{nu  
&lc@]y8  
(qcFGM22U  
try{ AR"2?2<mJ7  
URL url = new URL(sURL); :4AQhn^;"  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 09Hrn  
httpConnection.setRequestProperty("User-Agent","NetFox"); LUbhTc  
String sProperty = "bytes="+nStartPos+"-"; gl
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httpConnection.setRequestProperty("RANGE",sProperty); .[={Yx0!I  
Utility.log(sProperty); SA,~q&  
"+
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InputStream input = httpConnection.getInputStream(); *i#2>=)  
//logResponseHead(httpConnection); :J;U~emq
 
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byte[] b = new byte[1024]; K'OG-fn;  
int nRead; D@=]mh6vl  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Q\oa<R D5  
{ 3 98)\3o  
nStartPos += fileAccessI.write(b,0,nRead); f/\!=sa:  
//if(nThreadID == 1) *h^->+0n  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); *0U#Z]t  
} deVd87;@7[  
3}L3n*Ft#.  
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Utility.log("Thread " + nThreadID + " is over!"); bR`
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bDownOver = true; _z_YJ7A>  
//nPos = fileAccessI.write (b,0,nRead); b:1B >  
} I0-1
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catch(Exception e){e.printStackTrace ();} ;NP-tA)  
} z$<=8ox8e  
} l&& i`  
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//打印回应的头信息 6Ga'_P:  
public void logResponseHead(HttpURLConnection con) cT(nKHL  
{ /fQcrd7h  
for(int i=1;;i++) 5{H)r  
{ Vmz#u1gGT6  
String header=con.getHeaderFieldKey(i); ]H`wE_2tu  
if(header!=null) rpk8  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); PpRS4*nR  
Utility.log(header+" : "+con.getHeaderField(header)); +;,{`*W+N  
else &zn|),  
break; V7$ m.P#uM  
} lh-.I]>&`  
} 9G6)ja?W  
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public void splitterStop() \:'GAByy  
{ c coi  
bStop = true; x]VycS  
} +5fB?0D;  
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} g.\b@0Uy'  
f}dlQkZ(  
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/* &4E|c[HN
  
**FileAccess.java X&Oo[Z  
*//文件访问(定位，写) Tp;W  
package NetFox; uNewWtUb(  
import java.io.*; QXI~Toddj  
hLfWDf*T|  
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public class FileAccessI implements Serializable{ hMupQDv/I  
JP!e'oWxi  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 $%U}k=-  
RandomAccessFile oSavedFile; fe\'N4  
long nPos; -raK  
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public FileAccessI() throws IOException ^uX"04>;  
{ 4][VK/v+  
this("",0); W'Gh:73'}  
} !yg &zzP*  
,%Pn.E* r;  
:WH{wm|  
public FileAccessI(String sName,long nPos) throws IOException QVn2`hr  
{ 5hqXMs  
oSavedFile = new RandomAccessFile(sName,"rw"); TrZ!E`~  
this.nPos = nPos; E;yr46  
oSavedFile.seek(nPos); C&F% j.<  
} =}ZY`O*/  
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public synchronized int write(byte[] b,int nStart,int nLen) %AV3eqghCg  
{ [:,|g;
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int n = -1; 9[t-W:3c7  
try{ HH*,Oe  
oSavedFile.write(b,nStart,nLen); ;[zZI~wh  
n = nLen; q.:a4w J  
} b5p;)
#  
catch(IOException e) X:FyNUa  
{ >$<Q:o}^  
e.printStackTrace (); AB!({EIi  
} <qMX,h2  
4&]NC2I  
}zo-%#  
return n; CE183l\  
} P^
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} 5W{|?l{  
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/* G4F~V't  
**SiteInfoBean.java wMH13i3  
*/ LGy!{c  
package NetFox; Y5>'(A>  
;?o"{mbb  
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public class SiteInfoBean { j

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B*Q.EKD8s  
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private String sSiteURL; //Site's URL E;a9RV|  
private String sFilePath; //Saved File's Path oRn5blj  
private String sFileName; //Saved File's Name IetV]Ff6  
private int nSplitter; //Count of Splited Downloading File qyzeAK\Ia  
(w'k\y  
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public SiteInfoBean() 87V
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{//nSplitter的缺省值为5 Zfr?(y+3  
//default value of nSplitter is 5 (i'wa6[E8  
this("","","",5); j%0g*YI  
} 7`X9s~B  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) dZbG#4oO  
{ *Oe;JqQkK  
sSiteURL= sURL; 4gm(gY>[  
sFilePath = sPath; #`Et{6WS  
sFileName = sName; 20uR?/|@  
this.nSplitter = nSpiltter; qoD M!~  
!FnH;  
X"G3lG  
} yIThzyS  
hta$k%2  
)6zwprH!  
public String getSSiteURL() 4fzM%ku  
{ gs|%3k|  
return sSiteURL; )@YrHS4  
} Z.0^:rVp~  
i`:r2kU:*W  
whg?X&j\V  
public void setSSiteURL(String value) {GH 0 J"  
{ <<![3&p#  
sSiteURL = value; {=d\t<p*n  
} BPKeG0F7  
.~ W^P>t  
Icf@uQ6  
public String getSFilePath() ffyKAZ{]po  
{ "|"bo5M:   
return sFilePath; ',* 6vbII  
} Z5{M_^  
dDk<J;~jGJ  
HgX4RSU  
public void setSFilePath(String value) {B
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{ Fx0<!_tY-  
sFilePath = value; x2T

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} 2S8/ lsB  
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}g _#.>D+  
public String getSFileName() Tr}c]IP*  
{ 6q8qq/h)  
return sFileName; 6i\b&  
} fr\UX}o  
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4 ITSDx  
public void setSFileName(String value) }qXi;u))  
{ +B'9!t4 2  
sFileName = value; y?aOk-TaRA  
} *Qg/W?"m  
<OW` )0UX  
+;z4.C{gM  
public int getNSplitter() Hj;j\R >2  
{ +3t(kQ  
return nSplitter; 3!CI=(^IY  
} ;LH?Qu;e  
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public void setNSplitter(int nCount) "$:nz}  
{ /sdkQ{J!.  
nSplitter = nCount; ({zp$P}  
} .'7o,)pJ<  
} JCaT^KLz  
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})bTQj7  
/* 1rE
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**Utility.java P/Sv^d5=e  
*/ Mk[_y
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package NetFox;
*+qXXCA  
haa[ob6T  
**0Y*Ax@  
public class Utility { h.~S^uKi*  
UXa3>q>  
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public Utility() m=NX;t  
{ 0t*q5pAG".  
jB?Tua$,s  
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}
|n67!1  
bEy j8=P;  
//线程睡眠 Fv5@-&y$W  
public static void sleep(int nSecond) |'=R`@w~0  
{ ='OPU5(;O  
try{ O-bC+vB]M  
Thread.sleep(nSecond); 0=(5C\w2  
} #xE"];  
catch(Exception e) @oug^]a  
{
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e.printStackTrace (); 7ktf =Y  
} M.!U;U<?  
} o& $Fc8bH  
oe4Fy}Y_;  
//日志 M_UhFY='  
public static void log(String sMsg) Y R#_<o  
{ {o5E#<)  
System.err.println(sMsg); (+bk +0  
} _i6G)u&N  
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qeSxE`E"  
public static void log(int sMsg) nP4jOq*H  
{ j$A~3O<e"  
System.err.println(sMsg); srJ,Jr(  
} 3(}HD*{E[@  
} p^7ZFUP  
KS1Z&~4  
[|xHXcW  
/* nXk<DlTws  
**TestMethod.java T
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*/ &T}~h^/t  
package NetFox; ,H1j&]E!  
=?0o5|u]  
D*DCMMp=0  
public class TestMethod { y7ijT='8  
.& B_\*  
+KrV!Taf  
public TestMethod() 9]Uvy|  
{ ///xx/weblogic60b2_win.exe VL
A9&.*@  
try{ $^y6>@~  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); H)G ^ Y1  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); W$v5o9\Px  
SiteFileFetch fileFetch = new SiteFileFetch(bean);  o-_0  
fileFetch.start(); ?o"wyF A*  
} yx4B!U  
catch(Exception e){e.printStackTrace ();} a(
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k2"Z:\?z  
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} +k
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"+[
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public static void main(String[] args) P'KaWu9z  
{ i_)j K  
new TestMethod(); {Fta4D_1N  
} Ef;_im  
} n1a;vE{!  
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