http断点续传简单实现（java)

/* "n`z`{<n  
**SiteFileFetch.java aEvbGo  
*/ )LIn1o_,  
package NetFox; & ]]l0B  
import java.io.*; /\# f@Sg  
import java.net.*; 1=C12  
2/folTR7  
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public class SiteFileFetch extends Thread { h!K" ;qw  
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5;HGS{`  
SiteInfoBean siteInfoBean = null; //文件信息Bean |[Fb&x  
long[] nStartPos; //开始位置 SFd_
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long[] nEndPos; //结束位置 ){w{#  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 gqy>;A:kO  
long nFileLength; //文件长度 -5+Yz9pv[  
boolean bFirst = true; //是否第一次取文件 1' U  
boolean bStop = false; //停止标志 *2->>"kh  
File tmpFile; //文件下载的临时信息 ?L7DVwVa,I  
DataOutputStream output; //输出到文件的输出流 2=n`z)R  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） T+@i;M   
public SiteFileFetch(SiteInfoBean bean) throws IOException < $e#o H  
{ 69)"T{7  
siteInfoBean = bean; &Wcz~Gx3Q  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); q
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tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); &BrFcXF  
if(tmpFile.exists ()) Lr"cO|F  
{ h7q{i|5  
bFirst = false; 5rB>)p05[  
read_nPos(); 5l1R")0`t_  
} 7
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else K+!e1 '  
{ 4Ii5V c  
nStartPos = new long[bean.getNSplitter()]; jaodcT0  
nEndPos = new long[bean.getNSplitter()]; IRx%L?  
} "WQ6[;&V  
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} r^}0qO,XM  
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&  
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public void run() xm1di@  
{ j67ppt  
//获得文件长度 ah,f~.X_|  
//分割文件 'Xj^cX  
//实例FileSplitterFetch d=qVIpZ  
//启动FileSplitterFetch线程 V&:x+swt  
//等待子线程返回 /qy6YF8;y  
try{ <i</pA  
if(bFirst) !>> A@3  
{ qzbW0AM[M  
nFileLength = getFileSize(); $.4A?,d  
if(nFileLength == -1) L<@*6QH  
{ e[u}Vf  
System.err.println("File Length is not known!"); bKM*4M=k  
} >"bW'  
else if(nFileLength == -2) iSezrN  
{ <ytzGDx  
System.err.println("File is not access!"); zhs@YMY  
} 5H XF3  
else vRC >=y*=  
{ 5["3[h  
for(int i=0;i<nStartPos.length;i++) 5uQ+'*xN%  
{ f;BY%$  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); D1ZyJs#  
} 4h|*r !  
for(int i=0;i<nEndPos.length-1;i++) g]: [^p  
{ 0j(U &  
nEndPos = nStartPos[i+1]; cWx`y><  
} >dJuk6J&c&  
nEndPos[nEndPos.length-1] = nFileLength; VqW5VLa  
} ?SFQx\/  
} j [lS.Lb  
ub~ t}  
v:4j3J$z  
//启动子线程 ; >H1A  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; CYy=f-  
for(int i=0;i<nStartPos.length;i++) NT5=%X]  
{ I*.nwV<  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), :Q("   
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), F*@2)  
nStartPos,nEndPos,i); iKrk?B<  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); we`BqZV  
fileSplitterFetch.start(); #W)m({}  
} ?g4Rk9<!i  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), V/2NIh  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); '[liZCg  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", CdRJ@Lf  
nEndPos = " + nFileLength); ?s
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// fileSplitterFetch[nPos.length-1].start(); GxD`M2  
-V6caVlg  
[%bGs1U  
//等待子线程结束 EQ~<NzRp=  
//int count = 0; %50)?J=zB  
//是否结束while循环 y@~ VE5N  
boolean breakWhile = false; }8tF.QjR|  
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while(!bStop) <A Hzs  
{ R;Dj70g  
write_nPos(); ;L
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Utility.sleep(500);
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breakWhile = true; C @<T(`o  
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v; i4ZSV^A  
for(int i=0;i<nStartPos.length;i++) xA7~"q&u  
{ tcXXo&ZS  
if(!fileSplitterFetch.bDownOver) yZNG>1N  
{ BZQ}c<Nl  
breakWhile = false; oFP8s[B  
break; ugTsI~aE  
} (+(@P*c1  
} ?ld&}|W~  
if(breakWhile) 6ScB:8M  
break; GB Yy^wjU  
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Y|r7gy9%  
//count++; 1!.-/  
//if(count>4) dX/7n=  
// siteStop(); zJy=1r  
} YdO*5Gb6  
tWy.Gz\  
tlp,HxlP  
System.err.println("文件下载结束！"); P#V!hfM  
} G1jj:]1  
catch(Exception e){e.printStackTrace ();} e&ysj:W5 "  
} 46NuT]6/4  
o+=wQ$"tP  
o 7kg.w|  
//获得文件长度 #&kj>  
public long getFileSize() MwRLv,&"  
{ *h0D,O"0  
int nFileLength = -1; m_0y]RfG  
try{ .
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URL url = new URL(siteInfoBean.getSSiteURL()); w
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); \:{K",2  
httpConnection.setRequestProperty("User-Agent","NetFox"); xgcJEox!  
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int responseCode=httpConnection.getResponseCode(); ,V!"4T,Z  
if(responseCode>=400) 7u&l]NC?y  
{ f:+/=MW  
processErrorCode(responseCode); q&z'S
 
return -2; //-2 represent access is error oB5\^V$  
} F|> 3gW  
G!$~'o%/  
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String sHeader; FulFEnSV  
].xSX0YQ%  
%:`v
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for(int i=1;;i++) o]&q'>Rf  
{ /jJD {  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 6:|;O  
//Utility.log(in.readLine()); `$JvWN,kB  
sHeader=httpConnection.getHeaderFieldKey(i); ?
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if(sHeader!=null) R&(OWF;~,  
{ WcqR; Nm  
if(sHeader.equals("Content-Length")) EQlb:;j  
{ :lo5,B;k  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); lFt!  
break; xk~gGT&  
} *nU5PSs  
} 0yC~"u[N Y  
else n',X,P
0  
break; !1I# L!9  
} GalSqtbmDt  
} {Ia1H  
catch(IOException e){e.printStackTrace ();} QnOgF3t  
catch(Exception e){e.printStackTrace ();} k"cMAu.  
;]1t|td8  
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Utility.log(nFileLength); }nPt[77U_7  
*$%~/Q@]  
+ GQ{{B  
return nFileLength; $,by!w'e:l  
} ?:9y !Q=  
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V WZpEi  
//保存下载信息（文件指针位置） 2o<*rH  
private void write_nPos() gq+0t  
{ >I4BysR  
try{ T2Z$*;,>T  
output = new DataOutputStream(new FileOutputStream(tmpFile)); HI|egf@  
output.writeInt(nStartPos.length); =nCA=-Jv  
for(int i=0;i<nStartPos.length;i++) dj(&"P  
{ -(TC'  
// output.writeLong(nPos); *Lrrl  
output.writeLong(fileSplitterFetch.nStartPos); 4dFr~ {  
output.writeLong(fileSplitterFetch.nEndPos); {2:baoG-  
} ?aTH<  
output.close(); QEqYqAGzu|  
} Mu`_^gG  
catch(IOException e){e.printStackTrace ();} eG(YORkR  
catch(Exception e){e.printStackTrace ();} /~'C!so[v  
} Wo&22,
EB  
+I5\`By=  
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//读取保存的下载信息（文件指针位置） QDYuJ&!h  
private void read_nPos() ]>)shH=Yx
 
{ l[[`-f8j  
try{ H][TH2H1  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); :MF`q.:X  
int nCount = input.readInt(); `uPO+2  
nStartPos = new long[nCount]; xL_QTj  
nEndPos = new long[nCount]; wry`2_c  
for(int i=0;i<nStartPos.length;i++) ."dT6uE  
{ 9
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nStartPos = input.readLong(); 5(CInl  
nEndPos = input.readLong(); 
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} BEb?jRMjLg  
input.close(); i5le0lM  
}
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catch(IOException e){e.printStackTrace ();} ?0X$ox  
catch(Exception e){e.printStackTrace ();} @Un/,-ck  
} ;/+<N  
[/hoNCH!  
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private void processErrorCode(int nErrorCode) Ld_uMe?Z  
{ LI}e_=E  
System.err.println("Error Code : " + nErrorCode); 19GF%+L ,  
} <$?#P#A  
)R `d x  
83vZR
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//停止文件下载 >b\|%=(x!*  
public void siteStop() v0) %S  
{ 0);5cbV7i  
bStop = true; -<x%  
for(int i=0;i<nStartPos.length;i++) ,?m@Ko7Y  
fileSplitterFetch.splitterStop(); YC%xW*  
dl=)\mSFjF  

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} Y~*p27@fR  
} oO[eer_S-  
//负责部分文件的抓取 Hz,Gn9:p  
**FileSplitterFetch.java GtmoFSZ  
*/ Y{j~;G@Wl  
package NetFox; `/m]K~~  
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import java.io.*; FYik}
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import java.net.*; >yn?@ve@  
5,XEN$^  
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public class FileSplitterFetch extends Thread { a+z>pV|  
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String sURL; //File URL AUF[hzA  
long nStartPos; //File Snippet Start Position n+=7u[AZi  
long nEndPos; //File Snippet End Position ).,twf58  
int nThreadID; //Thread's ID Nz{q
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boolean bDownOver = false; //Downing is over &0T7Uv-`  
boolean bStop = false; //Stop identical ZJbaioc\  
FileAccessI fileAccessI = null; //File Access interface -{*3<2rFK  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException pR0!bgC  
{ >Q=e9L=  
this.sURL = sURL; u=@zYA(  
this.nStartPos = nStart; hH>a{7V  
this.nEndPos = nEnd; #QlxEs#%  
nThreadID = id; B7C<;`5TiD  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 0K"+u9D^  
} i885T'  
:twp95{R1  
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public void run() cyd_xB5K  
{ A#q.)8  
while(nStartPos < nEndPos && !bStop) lu>G=uCJ  
{ s +S6'g--  
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try{ &Pv$nMB$I  
URL url = new URL(sURL); |a[" ^ 2  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); A-vYy1,'  
httpConnection.setRequestProperty("User-Agent","NetFox"); a>#$&&oQ0  
String sProperty = "bytes="+nStartPos+"-"; aTHf+;  
httpConnection.setRequestProperty("RANGE",sProperty); .y
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Utility.log(sProperty);  3k6Dbz  
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L1lDDS#  
InputStream input = httpConnection.getInputStream(); F_@` <d!  
//logResponseHead(httpConnection); %eHr^j~w$  
cc=_KYZ1k  
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byte[] b = new byte[1024]; }<
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int nRead; #Z]Cq0=  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) CPsl/.$tC  
{ {1UU `d  
nStartPos += fileAccessI.write(b,0,nRead);
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//if(nThreadID == 1) p `oB._ R  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ,lCFe0>k!=  
} Xq"9TYf$  
V=1yg24B<  
Y -BZV |  
Utility.log("Thread " + nThreadID + " is over!"); KvPLA{  
bDownOver = true; H^B,b!5i  
//nPos = fileAccessI.write (b,0,nRead); xV`)?hEXFh  
} -{?xl*D  
catch(Exception e){e.printStackTrace ();} "{S4
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} *.$ov<E.  
} &j'k9C2p  
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* kL>9  
//打印回应的头信息 ):+^893)  
public void logResponseHead(HttpURLConnection con) k|]l2zlT  
{ "j&p3  
for(int i=1;;i++) =RWY0|f  
{ DKlHXEt
>  
String header=con.getHeaderFieldKey(i); 01aw+o  
if(header!=null) RM%Z"pc Y6  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); mT j  
Utility.log(header+" : "+con.getHeaderField(header)); qncZpXw^  
else us8ce+  
break; H-WNu+  
} l)KN5V  
} SzG %%CXH_  
(7~vOWs:[  
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public void splitterStop() ][OkydE  
{ +K=RMqM-8  
bStop = true; geM`O|Np  
} sSiZG  
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} \"yR[.Q?   
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/3"S_KE1@+  
/* &7,/^ >">  
**FileAccess.java M-!#-l  
*//文件访问(定位，写) Z +<Y.*6  
package NetFox; FNl^ lj`Y  
import java.io.*; rhQO#_`  
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}ZwnG=7T?  
public class FileAccessI implements Serializable{ &t@ $]m(  
phwq#AxQ  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 X5tV Xd  
RandomAccessFile oSavedFile; Df1eHa5-7  
long nPos; zcEpywNP  
</fTn_{2s8  
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public FileAccessI() throws IOException 1-!|_<EW1  
{ kl&_O8E+K  
this("",0); iIo>]\Pw  
} ,*p(q/kJh~  
!<-+}X+o8$  
b DF_  
public FileAccessI(String sName,long nPos) throws IOException YWq{?'AaR
 
{ @zix%x  
oSavedFile = new RandomAccessFile(sName,"rw"); sg]g;U  
this.nPos = nPos; PO2]x:  
oSavedFile.seek(nPos); r7)iNTQ1  
} E?mW4?  
.e:+Ek+  
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public synchronized int write(byte[] b,int nStart,int nLen) 8,m:  
{ 8HSGOs =8  
int n = -1; F|WH
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try{ %N<>3c<8P  
oSavedFile.write(b,nStart,nLen); C|ou7g4'p  
n = nLen; \ItAc2,Fl  
} ~1{~iB2G  
catch(IOException e)  ~#zb  
{ L\<J|87p?  
e.printStackTrace (); %cMayCaI!@  
} J=DD/Gp  
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AWmJm)  
return n; qSVg.<+   
} `,wX&@sN  
l%xeM!}  
495(V(+5  
} h"N#/zQ  
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/* gE!`9#..  
**SiteInfoBean.java t`4o&vsj=  
*/ jRdW=/q+(  
package NetFox; U09@pne8  
RKz _GEH)  
y|D-W>0cX3  
public class SiteInfoBean { `VOLw*Ci  
3j$,x(ua9  
VzFzVeJ  
private String sSiteURL; //Site's URL dU"C=c(w\  
private String sFilePath; //Saved File's Path _k W:FB  
private String sFileName; //Saved File's Name xJ|Z]m=d   
private int nSplitter; //Count of Splited Downloading File x\(yjNZH  
TGPHjSZ1  
7o M]qLF  
public SiteInfoBean() EY!
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{//nSplitter的缺省值为5 $%J$  
//default value of nSplitter is 5 o Bp.|8-  
this("","","",5); 5s2/YG=  
} >5]w\^QN9_  
"[]J[!}x  
4>[tjz.?k  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) B.[5N;c  
{ ["?WVXCF8|  
sSiteURL= sURL; < 'qtqUL\  
sFilePath = sPath; k
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sFileName = sName; V=H}Ecd  
this.nSplitter = nSpiltter; `_+m3vHG  
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} p$%g$K  
 PYYO-Twg  
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public String getSSiteURL() - e"XEot~  
{ 1HNX6  
return sSiteURL; z0&I>P
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} ]r1
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public void setSSiteURL(String value) o!t1EPJE*  
{ -wV0Nv(V8  
sSiteURL = value; wZUR  
} 3H
47 vm(`  
[
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\8X8NCM  
public String getSFilePath() (vf5qF^  
{ FwGMrJW  
return sFilePath; c'6$`nC  
} F1o"H/:n  
NBZ>xp[U  
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public void setSFilePath(String value) #8jH_bi  
{ \OXKK<^$uK  
sFilePath = value; }GTy{Y*&  
} 3/hAxd  
0=J69Yd  
U_,K_6vj  
public String getSFileName() &U/~*{  
{ QCWk[Gx  
return sFileName; cM'5m  
} 9^c"HyR  
$$G^#t1=XZ  
"ae55ft//  
public void setSFileName(String value) yo0?QRT  
{ _j2h3lCT  
sFileName = value; !P26$US%P  
} rJm%qSZz  
{n%U2LVL  
$yb8..+  
public int getNSplitter() Q-N.23\1  
{  qz:_T  
return nSplitter; H{T)?J~  
} dfq5P!'  
YR`Mi.,Sfm  
\ o&i63u  
public void setNSplitter(int nCount) !kfnqe?|  
{ [}_ar  
nSplitter = nCount; 7e"(]NC84  
} uNY]%[AnJ  
} !f\6=Z?>3  
DEC,oX!bI1  
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/* 3?uP$(l  
**Utility.java T't^pO-`  
*/ v+=_  
package NetFox; J=U7m@))Y#  
Q$9`QY*6"p  
b\\?aR |  
public class Utility { vu.f B4  
KXFa<^\o  
!<2*B^   
public Utility() ':w6{b  
{ n%<.,(.(S  
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F<w/@.&m  
} &,&oTd.  
i9M6%R1m}E  
//线程睡眠 m%E7V{t  
public static void sleep(int nSecond) ,O(XNA(C  
{ 4"j5@bppJ  
try{ }H,A T  
Thread.sleep(nSecond); ()>\D  
} j{P,(-  
catch(Exception e) :7!/FBd  
{ 8LwbOR"  
e.printStackTrace (); #PA"l`"  
} 6CU8BDN  
} 1.H"$D>TC  
^HL#)fK2I  
//日志 XfsCu>  
public static void log(String sMsg) X>|.BvY|  
{ ]3QQ"HLcp  
System.err.println(sMsg); _L!"3  
} 6<t\KMd  
73.o{V  
6v1#i  
public static void log(int sMsg) %9NGVC  
{ g}qK$>EPS  
System.err.println(sMsg); xD1B50y U  
} IW1]H~1w  
} ,?#-1uIGL>  
+dh]k=6  
tXKhkt`  
/* y9)l,@D  
**TestMethod.java Qw5M\   
*/ xHr  
package NetFox; h=4{.EegG&  
9Jk(ID'c  
v @N8v  
public class TestMethod { "3j0)  
G:e}>'  
3^su%z_%  
public TestMethod() IB*%PMTF  
{ ///xx/weblogic60b2_win.exe U0N[~yW(t1  
try{ ]aakEU  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); -GKelz?h>  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); LbYI{|_Js  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ?n@PZL= ]  
fileFetch.start(); (%fGS
.TR  
} kkOYC?zE?  
catch(Exception e){e.printStackTrace ();} Mc6Cte]3|  
nC&rQQFF  
@xkM|N?  
} ?I@3`?'  
wc,y+C#V  
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public static void main(String[] args) &1':s|c  
{ Jc%>=`f  
new TestMethod(); &&<^wtznO  
} mifYk>J^9  
} #uXOyiE  
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