http断点续传简单实现（java)

/* H]7;OM/g  
**SiteFileFetch.java " '/$ZpY
 
*/ ;9R;D,Gk!  
package NetFox; Jh'\ nDz@e  
import java.io.*; f}cz_"o4  
import java.net.*; B)M& FO  
$}/ !mXI5  
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public class SiteFileFetch extends Thread { S:En9E  
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SiteInfoBean siteInfoBean = null; //文件信息Bean uII:Y{G  
long[] nStartPos; //开始位置 bvMa|;f1  
long[] nEndPos; //结束位置 3:h9cO/9  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Ge>%?\  
long nFileLength; //文件长度 B|Rnh;B-  
boolean bFirst = true; //是否第一次取文件 2I#4jy/g  
boolean bStop = false; //停止标志 ]jz%])SzH  
File tmpFile; //文件下载的临时信息 [1Yx#t  
DataOutputStream output; //输出到文件的输出流 -PSI^%TR#  
w8Mi:;6  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） XKU+'Tz  
public SiteFileFetch(SiteInfoBean bean) throws IOException qi\!<clv  
{ Sh=Px9'i  
siteInfoBean = bean; R;_U BQ)  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ,rp-`E5ap  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); YEWHr>&Z  
if(tmpFile.exists ()) w-%
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{ ]r{-K63P{!  
bFirst = false; <z*SO a  
read_nPos(); w$cic  
} oO4 Wwi  
else l*|^mx^Q  
{ <
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nStartPos = new long[bean.getNSplitter()]; K`nI$l7hg  
nEndPos = new long[bean.getNSplitter()]; j3bTa|UdT  
} %7PprN0>  
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} IwIk;pB O  
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public void run() Hb3+$vJ^  
{ rdsm /^,s  
//获得文件长度 uw@z1'D[i"  
//分割文件 n2Oi< )  
//实例FileSplitterFetch {g2cm'hD  
//启动FileSplitterFetch线程 IPU'M*|Q  
//等待子线程返回 _,i]ra{%  
try{ o
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if(bFirst) FKd5]am  
{ fn zj@_{|  
nFileLength = getFileSize(); @xJ qG"  
if(nFileLength == -1) j w)Lofn  
{ ~a[]4\m;  
System.err.println("File Length is not known!"); E/<[G?  
} pC
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else if(nFileLength == -2) "msCiqF{z  
{ x=yU }lsV  
System.err.println("File is not access!"); x-0IxWD%  
} \#[W8k<Z  
else )
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{
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for(int i=0;i<nStartPos.length;i++) 9x,Aqr$t  
{ "3{xa;c  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ~pn9x;N%H  
} 6u3DxFiTm  
for(int i=0;i<nEndPos.length-1;i++) w|x=^  
{ z I`'n%n=  
nEndPos = nStartPos[i+1]; UAT46  
} _7YAF,@vT  
nEndPos[nEndPos.length-1] = nFileLength; C|Bk'<MI  
} zYdSg<[^  
} ~F*p
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//启动子线程 n37C"qJ/i  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ]<q{0.  
for(int i=0;i<nStartPos.length;i++) $V~r*#$.  
{ GA{>=Q_~  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), $EbxV"b+  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 2#LcL  
nStartPos,nEndPos,i); f)q\RJA)X  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); !Y-MUZ$f  
fileSplitterFetch.start(); kwdmw_  
} ^ 3LM%B  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), $=$I^hV  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Z9ciS";L  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", v@;:aN  
nEndPos = " + nFileLength); j-ugsV`2=*  
// fileSplitterFetch[nPos.length-1].start(); tnbaU%;|J  
L1`^~m|  
0/<}.Z]  
//等待子线程结束 [kzcsJ'/e  
//int count = 0; cD8.rRyD  
//是否结束while循环 Q{!l
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boolean breakWhile = false;  M}}9  
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{o7ibw=E)  
while(!bStop) h[3N/yP  
{ c6s*u%+},  
write_nPos(); "uCx.Q9ef  
Utility.sleep(500); T1;yw1/m5\  
breakWhile = true; B_M)<Ad  
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for(int i=0;i<nStartPos.length;i++) 673v  
{ _%!C;`3Y  
if(!fileSplitterFetch.bDownOver) F8YD:   
{ uJMF\G=nb  
breakWhile = false; $Ha?:jSc  
break; VZF/2d84&w  
} <8!mmOK1  
} e>1^i;f  
if(breakWhile) q#I/N$F  
break; C;wN>HE  
b#P,  
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//count++; sU4(ed\gI\  
//if(count>4) :q;vZ6Xd  
// siteStop(); Vlce^\s;  
} (iGk]Rtzt  
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System.err.println("文件下载结束！"); 5wRDH1z@{  
} >9F,=63A  
catch(Exception e){e.printStackTrace ();} Q <^'v>~n  
} 8;p6~&).C~  
kX\t0'=]  
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//获得文件长度 O~9 %!LAu  
public long getFileSize() 6YrkS;_HS  
{ .Q?cNSWU  
int nFileLength = -1; 2#@S6zc  
try{ )& %X AW{  
URL url = new URL(siteInfoBean.getSSiteURL()); [f.[C5f%"'  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); (p68Qe%OuG  
httpConnection.setRequestProperty("User-Agent","NetFox"); Lh"Je-x<<  
@= 6}w_  
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int responseCode=httpConnection.getResponseCode(); ,y,NVF  
if(responseCode>=400) i+Px &9o<9  
{ KI-E=<zt  
processErrorCode(responseCode); z>vz
XM  
return -2; //-2 represent access is error Ws4aCH1  
} r3hjGcpaX  
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String sHeader; bL!NT}y`  
#; E,>0  

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for(int i=1;;i++) !V
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{ :Py/d6KK  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); L/<^uO1  
//Utility.log(in.readLine()); {08UBnR  
sHeader=httpConnection.getHeaderFieldKey(i); iF{eGi  
if(sHeader!=null) 9/{+,RpC  
{ ai`fP{WlX  
if(sHeader.equals("Content-Length")) f<uLbJ6  
{ g!V;*[  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 8Y sn8  
break; Vg\EAs>f  
} M=x/PrY"R  
} WHvN6  
else @YU}0&  
break; ~ra2Xyl  
} +~ :1H.  
} b,~4O~z  
catch(IOException e){e.printStackTrace ();} ToCB*GlL  
catch(Exception e){e.printStackTrace ();} :!N 5daK  
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Utility.log(nFileLength); NV9D;g$Y  
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return nFileLength; -/B}XNW  
} E%3WJ%A  
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//保存下载信息（文件指针位置） I(s\ Q[  
private void write_nPos() Od^y&$|_%`  
{ SBAq,F'  
try{ E6NkuBQ((  
output = new DataOutputStream(new FileOutputStream(tmpFile)); MQD UJ^I$  
output.writeInt(nStartPos.length); >VE,/?71@  
for(int i=0;i<nStartPos.length;i++) L<J';#BD  
{ ]H[RY&GY  
// output.writeLong(nPos); Zu_m$Mx  
output.writeLong(fileSplitterFetch.nStartPos); Dvo.yn|kB  
output.writeLong(fileSplitterFetch.nEndPos); ;f^.7|
 
} zW!3>(L/  
output.close(); 3 {\b/NL$  
} z62
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catch(IOException e){e.printStackTrace ();} >9Fs)R]P  
catch(Exception e){e.printStackTrace ();}  |UZ#2  
} ]B:g<}5$4  
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//读取保存的下载信息（文件指针位置） vy,ER<  
private void read_nPos() FaPX[{_E  
{ Jq l#z/z  
try{ 0 4x[@f`  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); C^aP)& qt  
int nCount = input.readInt(); QSW03/_f  
nStartPos = new long[nCount]; gPT-zul  
nEndPos = new long[nCount]; 245(ajxHC  
for(int i=0;i<nStartPos.length;i++) bkceR>h%  
{ Qa5<go{  
nStartPos = input.readLong(); XGFU *g`kq  
nEndPos = input.readLong(); c`#E#  
} ]V6<h Psi  
input.close(); Ib*l{cxN  
} s!9.o_k  
catch(IOException e){e.printStackTrace ();} 5MQD:K2  
catch(Exception e){e.printStackTrace ();} !\}Dxt  
} ]~U4;  
]chcRc[!  
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private void processErrorCode(int nErrorCode) W7WHH \L/O  
{ oR[,?qu@f  
System.err.println("Error Code : " + nErrorCode); ipQJn_:2  
} wlAlIvIT  
8
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?NGM<nK;7  
//停止文件下载 9Y&n$svB  
public void siteStop() z~L4BY@z  
{ M+gQN}BAr  
bStop = true; ;'`T  
for(int i=0;i<nStartPos.length;i++) [`Ol&R4k  
fileSplitterFetch.splitterStop(); W% YJ.%I  
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} );kO27dg  
} aG%KiJ7KEN  
//负责部分文件的抓取 qy`@\)S/5  
**FileSplitterFetch.java Ih;6(5z  
*/ `ihlKFX  
package NetFox; `pn]jpW9  
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import java.io.*; _SY<(2s]B  
import java.net.*; mv/'H^"[_  
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public class FileSplitterFetch extends Thread { lf4-Ci*X  
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String sURL; //File URL yc8iT`
 
long nStartPos; //File Snippet Start Position (*;b\h  
long nEndPos; //File Snippet End Position
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int nThreadID; //Thread's ID 8Focs p2  
boolean bDownOver = false; //Downing is over )TP1i  
boolean bStop = false; //Stop identical 7m~+
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FileAccessI fileAccessI = null; //File Access interface Uq<c+4)5  
}y(1mzb  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 94=Wy-  
{ M9.jJf  
this.sURL = sURL; Om0Z\GP=  
this.nStartPos = nStart; 'v GrbmK  
this.nEndPos = nEnd; 6H+gFXIv  
nThreadID = id; Gw:8-bxS  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ;2(8&.  
} EoD;'+d  
= 7d{lK  
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public void run() w= |).qQ]  
{ ]OL O~2
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while(nStartPos < nEndPos && !bStop) <.HX_z3l  
{ TppR \[4]  
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try{ ]R32dI8N  
URL url = new URL(sURL); F"FGPk  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); $bIVD  
httpConnection.setRequestProperty("User-Agent","NetFox"); =3$JeNK9  
String sProperty = "bytes="+nStartPos+"-"; =e=sK'NvD  
httpConnection.setRequestProperty("RANGE",sProperty); 2a'b}<|[(  
Utility.log(sProperty); g VX  
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m X{_B!j^  
InputStream input = httpConnection.getInputStream(); (S$ziV  
//logResponseHead(httpConnection); \2KwF}[m  
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byte[] b = new byte[1024]; FBJw (.Jr  
int nRead; Xb6X'rY  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) xTiC[<j  
{ %$}aWzQxll  
nStartPos += fileAccessI.write(b,0,nRead); '=C)Hj[D  
//if(nThreadID == 1) OPOL-2<wiy  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); >Vc;s!R  
} *WdnP.'Y  
d|#sgGM<8  
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Utility.log("Thread " + nThreadID + " is over!"); MWTzJGRT  
bDownOver = true; $L%gQkz_  
//nPos = fileAccessI.write (b,0,nRead); z/Z 0cM#  
} }TE4)vXs  
catch(Exception e){e.printStackTrace ();} V|9<*  
} )RV.N}NU  
} uflRW+-2  
6/
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4UP#~  
//打印回应的头信息 d h5%  
public void logResponseHead(HttpURLConnection con) x[L/d"Wf  
{ ~Y;_vU  
for(int i=1;;i++) )~@iM.}S2  
{ <E/"v  
String header=con.getHeaderFieldKey(i); 4FLL*LCNX  
if(header!=null) 3>O=d>  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ,Hq*zc
c  
Utility.log(header+" : "+con.getHeaderField(header)); JSO'. [N  
else o+-G@16  
break; 3jx5Lou)&  
} BuwJR Ql.  
} {jVEstP  
LYM(eK5V  
eD<Kk 4){  
public void splitterStop() En&`m  
{ >2kjd  
bStop = true; F,
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} cow]qe6K  
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} uPZ<hG#K  
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*.g@6IkAQ  
/* ^j-w^)@T  
**FileAccess.java svT1b'=\$I  
*//文件访问(定位，写) )$Tcip`  
package NetFox; ?U^h:n  
import java.io.*; ;Nfd  
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!/]vt?v#^  
public class FileAccessI implements Serializable{ &uX|Ksq  
1ig#|v*+  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 335\0~;3  
RandomAccessFile oSavedFile; <Oyxzs  
long nPos; XwerQwO=  
97XGJ1HI  
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public FileAccessI() throws IOException =5zx]N1r  
{ ;R#:? r;t  
this("",0); +|SvJ  
} %b)~K|NEFf  
cag9f?w@V  
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public FileAccessI(String sName,long nPos) throws IOException N=?! ~n9Q-  
{ 1Vden.H*CI  
oSavedFile = new RandomAccessFile(sName,"rw"); ,vN0Jpf}\8  
this.nPos = nPos; `;'fCO!  
oSavedFile.seek(nPos); }'o[6#_*X  
} pbM"tr_A{  
bM%c*_$F7  
|ULwUi-r  
public synchronized int write(byte[] b,int nStart,int nLen) :zL.dJwa  
{ .W9/*cZV0  
int n = -1; p]7Gj&a  
try{ Q<e`0cu|p  
oSavedFile.write(b,nStart,nLen); UdS
u:V|  
n = nLen; 8G SO]R  
} cuw3}4m%  
catch(IOException e) _:tclBc8R  
{ zF F=v7[j  
e.printStackTrace (); o`@B*, @  
} 0 CJ4]mYl  
4]\t6,Cz8  
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return n; d\cwUXf J  
} kP6P/F|RcZ  
{mlJE>~%  
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} p2=Sbb  
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L
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/* zn |=Q$81  
**SiteInfoBean.java ;5*)kX  
*/ 9u'hC
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package NetFox; '(/ZJ88JP  
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public class SiteInfoBean { )
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1m/=MET]  
by {G{M`X  
private String sSiteURL; //Site's URL ,{C(<1  
private String sFilePath; //Saved File's Path GXEOgf#i  
private String sFileName; //Saved File's Name /WDz;,X  
private int nSplitter; //Count of Splited Downloading File cZRLYOC  
oE&Zf/  
y\ nR0m  
public SiteInfoBean() C { }s  
{//nSplitter的缺省值为5 4*UoTE-g$  
//default value of nSplitter is 5 {PM)D [$i  
this("","","",5); F_SkS?dB  
} tPS.r.0#^  
ksxacRA7\  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Ne]/ sQ0  
{ ;y#6Nx,:  
sSiteURL= sURL; 6TE RQ  
sFilePath = sPath; ?l_>rSly5  
sFileName = sName; Zq|oj^  
this.nSplitter = nSpiltter; ;8~`fK  
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A a2*f[  
} r +] J {k  
@o+T<}kWX  
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public String getSSiteURL() (k"oV>a|  
{ _"Q +G@@  
return sSiteURL; DytOS}/^9  
} LnJ/t(KV  
DA oOs}D  
:):=KowI  
public void setSSiteURL(String value) ,q#^_/?  
{ ]xfAdBi  
sSiteURL = value; s,^?|Eo;0  
} O0xL;@rBe  
W%09.bF  
]lF'o&v]  
public String getSFilePath() jlER_I]  
{ :^SpKe(7  
return sFilePath; NDB]8C  
} Z*kGWL  
"b*.>QuZ  
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public void setSFilePath(String value) =JyYU*G4  
{ 1fL@rR  
sFilePath = value; FTt7o'U  
} T\:3(+uK  
CF^7 {g(y_  
-8tWc]c |4  
public String getSFileName() l)z15e5X  
{ Q8M&nf  
return sFileName; %^"Tz,f  
} IxCEE5+`%  
t4?g_$>   
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public void setSFileName(String value) (FMYR8H*(  
{ *&e+z-E  
sFileName = value; 9B'l+nP  
} b]s=Uv#)  
mW 5L;>  
0+8ThZ?
n  
public int getNSplitter() %_1~z[Dv  
{ 76)(G/  
return nSplitter; j:|60hDz^  
} d\, 4Wet;#  
v?<x"XKR  
##u+[ !  
public void setNSplitter(int nCount) q yy.3-(  
{ 7F`QN18>(  
nSplitter = nCount; rK~362|mo  
} K 3&MR=#^  
} 5d
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KLqu[{y.'  
/* C3 0b}2  
**Utility.java iTD}gC  
*/ "JVzv U]  
package NetFox; +M@G 8l  
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public class Utility { F4Ft~:a  
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public Utility() p`1d'n[  
{ |gxU;"2`5~  
Xk]5*C]6<  
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} }#<Sq57n  
A>>@&c:(  
//线程睡眠 P>pkLP} Vo  
public static void sleep(int nSecond) R_vZh|  
{ )0AE*S  
try{ 'QT(TF>  
Thread.sleep(nSecond); 7!oqn'#>A  
} =oT@h 9VI  
catch(Exception e) U]hQ#a+  
{ Ffj:xZ9rk  
e.printStackTrace (); kc8GnKM&mc  
} Q(k$HP  
} wc bs-arH  
/GM-#q a  
//日志 2y_rsu\  
public static void log(String sMsg) J~gfMp.  
{ f`A  
System.err.println(sMsg); r-N2*uYtu  
} lu(G3T8  
(P`{0^O"}  
8ZG'?A+{  
public static void log(int sMsg) .2xypL8(  
{ m3_e]v3{o  
System.err.println(sMsg); P603P  
} FbFUZ^Zj  
} =#Vdz=.  
5\=9&{WjND  
ts?b[v  
/* &p;};n  
**TestMethod.java jcq(=7j  
*/ :jp?FF^j;  
package NetFox; ?783LBe  
hD>:WJ  
Fa+PN9M`?.  
public class TestMethod { =53LapTPJ  
3<mv9U(  
\|62E):i1  
public TestMethod() 87<y
_P@{  
{ ///xx/weblogic60b2_win.exe zZ32K@  
try{ 'hya#rC&(  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); w,}}mC)\*  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); [7I|8
  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ljt1:@SN(  
fileFetch.start(); 3:Z(tM&-O  
} m]"YR_  
catch(Exception e){e.printStackTrace ();} C4 Wdt  
?sS'T7r v  
-S,dG|  
} ]LSa(7>EU  
29qQ3M?  
[tD*\\IA  
public static void main(String[] args) iBo-ANnK9  
{ Uw&+zJ  
new TestMethod(); o~4n8  
} !zJ.rYZ=g`  
} ~-:CN(U  
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