http断点续传简单实现（java)

/* hMtf.3S7c  
**SiteFileFetch.java ]l8^KX'  
*/ tBpC: SG  
package NetFox; JU&+c6>  
import java.io.*; ~i 7^P9  
import java.net.*; Jaz?Ys|S  
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public class SiteFileFetch extends Thread { s.8{5jVG  
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SiteInfoBean siteInfoBean = null; //文件信息Bean gCyW Vp  
long[] nStartPos; //开始位置 6Cp]NbNrq  
long[] nEndPos; //结束位置 5ZBKRu  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 <tioJG{OT  
long nFileLength; //文件长度 r7qh>JrO  
boolean bFirst = true; //是否第一次取文件 kBN+4Dr/$  
boolean bStop = false; //停止标志 n?V+dC=F}  
File tmpFile; //文件下载的临时信息 kwsp9 0)  
DataOutputStream output; //输出到文件的输出流 0
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ge8/``=  
public SiteFileFetch(SiteInfoBean bean) throws IOException iQ"XLrpl  
{ f7}*X|_Y  
siteInfoBean = bean; )+fh-Ui  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); |ZQ@fmvL/p  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Rn@#d}  
if(tmpFile.exists ()) _Zr.ba  
{ P
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bFirst = false; +]Y,
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read_nPos(); 8,uB8C9  
} +zs4a96[  
else H$6`{lx,  
{ 3)RsLI9  
nStartPos = new long[bean.getNSplitter()]; 3'X.}>o  
nEndPos = new long[bean.getNSplitter()]; 4 uQT5  
} F;>!&[h}G  
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} Ox-|JJ=  
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{*ob_oc  
public void run() `HBf&Z  
{ m?&1yU9  
//获得文件长度 )Dz+X9;g+  
//分割文件 KSrx[q  
//实例FileSplitterFetch n\Lb.}]1~  
//启动FileSplitterFetch线程 uDZT_c'Y  
//等待子线程返回 c}0@2Vf  
try{ x|5k<CiA  
if(bFirst) c?@T1h4  
{ fS`$'BQ  
nFileLength = getFileSize(); +U3m#Y)k  
if(nFileLength == -1) RZCq{|L  
{ H8On<C=  
System.err.println("File Length is not known!"); x_dy~(*  
} =3v]gOcO  
else if(nFileLength == -2) to$h2#i_  
{ 6w@ Ii;  
System.err.println("File is not access!"); @n": w2^B  
} \0gM o&  
else 9U%N@Dq`Z  
{ ^) s2$A:L  
for(int i=0;i<nStartPos.length;i++) cx0*X*  
{ Dmu/RD5X:  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); $81*^  
} w/K_B:s  
for(int i=0;i<nEndPos.length-1;i++) =i7`ek  
{ 
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nEndPos = nStartPos[i+1]; q')R4=0 K  
} [2{1b`
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nEndPos[nEndPos.length-1] = nFileLength; Ck|8qUz-  
} \R;`zuv  
} qhz]Wm P   
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//启动子线程 r'*}TM'8  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; yu/`h5&*  
for(int i=0;i<nStartPos.length;i++) .?Gd'Lp  
{ g'm+/pU)w)  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), #*(td<Cp  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), :B:"NyPA  
nStartPos,nEndPos,i); ^~A>8CQOU  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); &sL&\+=<(  
fileSplitterFetch.start(); <N9[?g)  
} JQ@E>o7_  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ?n ZY)  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); *NClfkZ  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", CtSl  
nEndPos = " + nFileLength); 3z&Fi;<+j  
// fileSplitterFetch[nPos.length-1].start(); }dd8N5b  
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H?X|(r|+  
//等待子线程结束 g #6E|n  
//int count = 0; k|H:  
//是否结束while循环 WV_.Tiy<  
boolean breakWhile = false; k<\$Oo
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bk  
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while(!bStop) 5w@4:$=I  
{ sH[ROm  
write_nPos(); I]EbodAyZ,  
Utility.sleep(500); Y1J=3Y  
breakWhile = true; % V8U(z  
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for(int i=0;i<nStartPos.length;i++) Xn%pNxUL  
{ L|}lccpI  
if(!fileSplitterFetch.bDownOver) ~15N7=wCM  
{ J\M>33zu  
breakWhile = false; h9G RI  
break; "pRtczxOgR  
} suzZdkMA  
} vz7J-CH  
if(breakWhile) cZ2kYn8  
break; ry`z(f  
/VN f{p  
CyXRi}W.  
//count++; "\o+v|;  
//if(count>4) z-.+x3&o @  
// siteStop(); m~-K[+ya`D  
} 5Ezw ~hn  
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System.err.println("文件下载结束！"); < F.hZGss7  
} O4V.11FnW  
catch(Exception e){e.printStackTrace ();} j+uLV{~g6  
} n4R(.N00  
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)]H-BIuGm  
//获得文件长度 .@@?Pj?)  
public long getFileSize() m;GbLncA  
{ P
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int nFileLength = -1; :lPb.UCY  
try{ 2;DuHO1  
URL url = new URL(siteInfoBean.getSSiteURL()); G(G{RAk>  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); EkjN{$*  
httpConnection.setRequestProperty("User-Agent","NetFox"); rzm:Yx  
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int responseCode=httpConnection.getResponseCode(); 5?3Me59  
if(responseCode>=400) Vt".%d/`7  
{ yl7&5)b#9  
processErrorCode(responseCode); mR?5G:W~R  
return -2; //-2 represent access is error I uMQ9&  
} 2Q/4bJpd  
a!"$~y$*  
!`,Sfqij  
String sHeader; 4'a=pnE$  
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for(int i=1;;i++) ;h*K}U  
{ =WyZX 7@R  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); -xEXN[\S  
//Utility.log(in.readLine()); ymx>i~>7J  
sHeader=httpConnection.getHeaderFieldKey(i); 4{rZppm  
if(sHeader!=null) 0 yuW*z  
{ }%'?p<^M  
if(sHeader.equals("Content-Length")) #xQr<p$L6  
{ O&4SCVZp  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); JGsx_V1t  
break; X[PZg{   
}
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} T_@K&<  
else Sjyoc<Uo  
break; {=!b/l;@  
} W&&;:Fr  
} |"/8XA  
catch(IOException e){e.printStackTrace ();} TgmnG/Z  
catch(Exception e){e.printStackTrace ();} )FF>IFHG  
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Utility.log(nFileLength); ZniB]k1  
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return nFileLength; H%UL%l$  
} J'SZ  
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//保存下载信息（文件指针位置） E*V`":efS  
private void write_nPos() bx{$Y_L+p  
{ fPn>v)lN{  
try{ / ';0H_  
output = new DataOutputStream(new FileOutputStream(tmpFile)); =vDEfO/T  
output.writeInt(nStartPos.length); @z4*.S&tz  
for(int i=0;i<nStartPos.length;i++) `\T]ej}zvI  
{ ]>LhkA@V  
// output.writeLong(nPos); 3DiLk=\~  
output.writeLong(fileSplitterFetch.nStartPos); !}v=N";c  
output.writeLong(fileSplitterFetch.nEndPos); u frW\X  
} s%C)t6`9  
output.close(); )uj Ex7&c  
} /'].lp  
catch(IOException e){e.printStackTrace ();} ~$:|VHl  
catch(Exception e){e.printStackTrace ();} bJRN;g  
} Szq/hv=Q  
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Bg5Wba%NK  
//读取保存的下载信息（文件指针位置） iOR_[y,  
private void read_nPos() 3L833zL  
{ zLD0RBj7p  
try{ 3 Nreqq  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); xy5lE+E_U  
int nCount = input.readInt(); tZ=E')!\  
nStartPos = new long[nCount]; \m7-rV6r  
nEndPos = new long[nCount]; cik!GA  
for(int i=0;i<nStartPos.length;i++) $@^pAP   
{ 2z6yn?'&L  
nStartPos = input.readLong(); K/tRe/t}  
nEndPos = input.readLong(); ORyE`h
 
} Z*y`R XE  
input.close(); )PG6gZYW  
} u.d).da  
catch(IOException e){e.printStackTrace ();} C8[&S&<_<  
catch(Exception e){e.printStackTrace ();} &Q;sSIc  
} Ss~;m']68  
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!/}O>v~o  
private void processErrorCode(int nErrorCode) =Z P%mW&;}  
{ WM| dKF  
System.err.println("Error Code : " + nErrorCode); |uqf:V`z:  
} #w,Dwy  
"^w]_^GD$d  
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//停止文件下载 q*\x0"mS/  
public void siteStop() p<TpK )  
{ ?]Pmxp H}  
bStop = true; &<wuJ%'>)Z  
for(int i=0;i<nStartPos.length;i++) QW$G  
fileSplitterFetch.splitterStop(); oFy=-p+C  
`tHvD=`m.  
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} |zQ4u  
} P;P%n  
//负责部分文件的抓取 %MrWeYd1  
**FileSplitterFetch.java 0'V5/W  
*/ )2V:  
package NetFox; eoai(&o0$  
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!n* +(lZ  
import java.io.*; 9Wnn'T@Tl  
import java.net.*; +?u~APjNN  
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]
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public class FileSplitterFetch extends Thread { .q `Hjmg<  
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String sURL; //File URL Fs{x(_LOr  
long nStartPos; //File Snippet Start Position q;<h[b?  
long nEndPos; //File Snippet End Position _CW(PsfY  
int nThreadID; //Thread's ID _AQb6Nb  
boolean bDownOver = false; //Downing is over ]8Q4BW  
boolean bStop = false; //Stop identical k 8UO9r[  
FileAccessI fileAccessI = null; //File Access interface 1u: gFUb  
6
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Svondc 4  
{ LXbP 2  
this.sURL = sURL; t?}zdI(4  
this.nStartPos = nStart; Min ^>  
this.nEndPos = nEnd; 7on.4/;M  
nThreadID = id; ?Cl%{2omO  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 |K.mP4CKY  
} Qa.<K{m#?  
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public void run() f!s=(H;  
{ Zb1<:[  
while(nStartPos < nEndPos && !bStop) q:dHC,
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{ t.laO. 3  
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R{ a"Y$  
try{ Q^ pmQ  
URL url = new URL(sURL); B[V+ND'(  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); U<CTubF  
httpConnection.setRequestProperty("User-Agent","NetFox"); p1&b!*o-&  
String sProperty = "bytes="+nStartPos+"-"; 7g%E`3)"  
httpConnection.setRequestProperty("RANGE",sProperty); Z?%zgqTXb  
Utility.log(sProperty); `&D|>tiz  
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InputStream input = httpConnection.getInputStream(); xYmxc9)2  
//logResponseHead(httpConnection); '7+4`E  
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byte[] b = new byte[1024]; ^ q<v{_  
int nRead; eu(:`uu  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) pL{U `5S  
{ (CsD*U`h  
nStartPos += fileAccessI.write(b,0,nRead); p4'G$]#  
//if(nThreadID == 1) .u4 W /  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); #7MUJY+ 9  
} ?)u@Rf9>  
#)C[5?{SNq  
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Utility.log("Thread " + nThreadID + " is over!"); P%#<I}0C  
bDownOver = true; CitDm1DXt/  
//nPos = fileAccessI.write (b,0,nRead); Kac' ;
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} ^R# E:3e  
catch(Exception e){e.printStackTrace ();} B]uc<`f  
} w]]8dz  
} jV4\A  
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//打印回应的头信息 tE)suU5Y  
public void logResponseHead(HttpURLConnection con) /+@p7FqlE  
{ jpO7'ivG  
for(int i=1;;i++) ,M^P!  
{ MP!d4  
String header=con.getHeaderFieldKey(i); nv@8tdrc  
if(header!=null) cVv;Jn  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); J/[=p<I)  
Utility.log(header+" : "+con.getHeaderField(header)); ~v6OsH%vx  
else J2'Nd'  
break; UFp,a0|  
} \lZf<f  
} z@B=:tf  
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public void splitterStop() 2vAQ  
{ _nbBIaHN{  
bStop = true; 9J9)AV  
} `Ye\p6v!+  
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8]M_z:F7F  
} il:$sd  
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/* }>
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**FileAccess.java v?& -xH-S  
*//文件访问(定位，写) 6P5Ih  
package NetFox; ENGg ~D  
import java.io.*; y5do1Z  
=gJb^ Gx(w  
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public class FileAccessI implements Serializable{ #m{UrTC  
;)!Sp:mHX  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 X&0 uI*r  
RandomAccessFile oSavedFile; G|( ]bvJ?  
long nPos; p' +  
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public FileAccessI() throws IOException }RwSp!}C  
{ 0o9 3iu=&  
this("",0); '+$EhFwD  
}
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public FileAccessI(String sName,long nPos) throws IOException lsy?Ac  
{ K9OY
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oSavedFile = new RandomAccessFile(sName,"rw"); xYhrO  
this.nPos = nPos; 1. rj'  
oSavedFile.seek(nPos); [BT/~6ovrZ  
} /C4^<
k\  
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public synchronized int write(byte[] b,int nStart,int nLen) il \$@Bn  
{ nSkPM5\TI  
int n = -1; !kE-_dY6)  
try{ R0L&*Bjm  
oSavedFile.write(b,nStart,nLen); ,;(PwJe  
n = nLen; -*m+(7G\  
} hb^7oq"a  
catch(IOException e) 'ul~7h;n  
{ 82]vkU  
e.printStackTrace (); yRiP{$E  
} tWoh''@#  
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return n; 9$|Gfyv  
} tc!wLnhG  
&b
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}  R#DwF,  
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^4`Px/&  
/* cPU/tkc  
**SiteInfoBean.java =n' 4?W@  
*/ l+g9 5mjP  
package NetFox; X0M1(BJgGo  
3neIR@W  
ulER1\W  
public class SiteInfoBean { }GZ}Q5  
@;H,gEH^  
{nvLPUL  
private String sSiteURL; //Site's URL wlEo"BA  
private String sFilePath; //Saved File's Path 1[t=XDz/e  
private String sFileName; //Saved File's Name ?w+Ix~k  
private int nSplitter; //Count of Splited Downloading File 
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public SiteInfoBean() }QsZ:J.  
{//nSplitter的缺省值为5 nYt/U\n!  
//default value of nSplitter is 5 XxaGp95so  
this("","","",5); 5n ^TR
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} z8J."27ND  
W":PG68  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) F1Hh7 F  
{ JB&\i#  
sSiteURL= sURL; `r_m+
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sFilePath = sPath; KV*xApb9y  
sFileName = sName; QZ?=M@|f  
this.nSplitter = nSpiltter; %Jf<l&K.`  
|/|  
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} 03iv
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$\"9<o|h  
public String getSSiteURL() <uc1D/~^:  
{ v
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return sSiteURL; toaYsiIkzW  
} {h KjD"?  
"aFhkPdWn  
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public void setSSiteURL(String value) wM_ 6{  
{ &l?+3$q  
sSiteURL = value; z 8*8OWM  
} 3F#+~^2  
8p!*?RRme[  
P N*JR  
public String getSFilePath() 7 ua6l[c  
{ /n4pXT  
return sFilePath; RuG-{NF{F  
} (LtkA|:  
zLD|/`  
)){xlFA}  
public void setSFilePath(String value) 6UE(f@  
{ Xm4CKuU@  
sFilePath = value; `PL[lP-<  
} 3[XQR8o  
#2:a[ ~Lf  
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public String getSFileName() T|"7sPgGR  
{ xc?}TPpt  
return sFileName; E&B{5/rv  
} Y?#i{ixX6n  
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public void setSFileName(String value) D0;tcm.$  
{ ~B$b)`*  
sFileName = value; !eJCM`cp  
} |8)Xc=Hz  
c {I"R8  
somfv$'B  
public int getNSplitter() oH2!5;A|  
{ 2BzqY`O  
return nSplitter; oY`qInM_  
} .~}z4r  
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%So]3;'  
public void setNSplitter(int nCount) )uP[!LV[e  
{ 5A&y]5-Q`  
nSplitter = nCount; *wi}>_\  
} !6w{(Rc(C  
} >m_v5K  
[$ :  
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/* YYRT.U'  
**Utility.java WP-jtZ?!"  
*/ }iIbc
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package NetFox; |xr32gs  
J
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public class Utility { F?Or;p5`Y  
J?P]EQU  
~_!ts{[E  
public Utility() SvK1.NUa  
{
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;Mj002.\G  
4Y tk!oS`  
} Xy#VQ{!  
iUr xJh  
//线程睡眠  }sMW3'V  
public static void sleep(int nSecond) #Y[H8TW  
{ /~}_hO$S  
try{ jeDlH6X'  
Thread.sleep(nSecond); J(d2:V{h  
} gwQvao  
catch(Exception e) 7dD.G/'  
{ p q
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e.printStackTrace (); wsg//Ec]  
} Rlw9$/D!Z  
} oA3d^%(c  
J0Four#MD  
//日志 1<uwU(  
public static void log(String sMsg) R!{7OkC  
{ *d l"wH&  
System.err.println(sMsg); xbC~C~#  
} hU,$|_WDy  
+ x_wYv  
rh$1-Y  
public static void log(int sMsg) ug6r]0]  
{ $T*KaX\{B  
System.err.println(sMsg); 3%NE/lw1  
} *IlQ5+3I  
} * NMQ  
*?Wtj  
H!JWc'(<$  
/* 0=m&^Jpp  
**TestMethod.java A;%kl`~iyz  
*/ (^S5Sc=  
package NetFox; ,#%SK;1<  
jI#z/a!j:  
-ddOh<U>  
public class TestMethod { UQdyv(jXq  
ocP*\NR  
|Y4q+sDW  
public TestMethod() ZPYH#gC&T  
{ ///xx/weblogic60b2_win.exe 0HPO"x3-O  
try{ a&:>Ped"  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); !>|`ly$6  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 2^bgC~2C1  
SiteFileFetch fileFetch = new SiteFileFetch(bean); [5LMt*Y  
fileFetch.start(); tz8
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}  f}-v  
catch(Exception e){e.printStackTrace ();} %9YA^ri  
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<|dj^.^  
} }u7D9_KU  
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public static void main(String[] args) ?7 X3P  
{ j5A\y^Kv  
new TestMethod(); kpY%&  
} ^B6`e^<  
} tpz=}q  
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