http断点续传简单实现（java)

/* _Xcn N:Rt  
**SiteFileFetch.java Kn;D?ioY  
*/ d(`AXyw  
package NetFox; '])2k@o@  
import java.io.*; O\KQl0*l\\  
import java.net.*; F/c$v  
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public class SiteFileFetch extends Thread { E; $+f  
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SiteInfoBean siteInfoBean = null; //文件信息Bean u"xJjS  
long[] nStartPos; //开始位置 K0pac6]  
long[] nEndPos; //结束位置 sM[I4.A3  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 _6@hTen`  
long nFileLength; //文件长度 UaG1c%7?X  
boolean bFirst = true; //是否第一次取文件 3riw1
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boolean bStop = false; //停止标志 UYP9c}_,4  
File tmpFile; //文件下载的临时信息
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DataOutputStream output; //输出到文件的输出流 Ter:sge7  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） zSvgKmNY  
public SiteFileFetch(SiteInfoBean bean) throws IOException *u6Y8IL1  
{ (h-*_a}F4  
siteInfoBean = bean; ,Tagj`@bHc  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); oB1>x^  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); gR^>3
n'  
if(tmpFile.exists ()) ~ (On|h  
{ LjFqZrH  
bFirst = false; t`'iU$:1f  
read_nPos(); 4\ c,)U}  
} q"qo.TPh|$  
else E\8  
{ b,TiMf9},h  
nStartPos = new long[bean.getNSplitter()]; 1S
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nEndPos = new long[bean.getNSplitter()]; r,P1^uHx  
} LA3<=R]  
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} &hIRd,1#  
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public void run() kUx&
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{ 3-Dt[0%{  
//获得文件长度 w2O!M!1  
//分割文件 2L_6x<u'  
//实例FileSplitterFetch =,!\~`^  
//启动FileSplitterFetch线程 /2M.~3gQ  
//等待子线程返回 \<0B1m  
try{ DciwQcG  
if(bFirst) =VLS/\A  
{ x3ERCqTR  
nFileLength = getFileSize(); cV{%^0?D  
if(nFileLength == -1) C8#@+Q.  
{ o ]Jv;Iy@?  
System.err.println("File Length is not known!"); s{ V*1$e~  
} ]maYUKqv}'  
else if(nFileLength == -2) UgB'[@McS  
{ 2>}xhQJ  
System.err.println("File is not access!"); C^t(^9  
} =S[yE]v^  
else 0Iud$Lu  
{ ?::NO Dg  
for(int i=0;i<nStartPos.length;i++) w(L>#?  
{ ^1:U'jIXO  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); oIGrA-T}  
} ~zm7?_"@]  
for(int i=0;i<nEndPos.length-1;i++) jUj<~:Q}3o  
{ TGuiNobD  
nEndPos = nStartPos[i+1]; V~GWl1#7  
} 1%M&CX  
nEndPos[nEndPos.length-1] = nFileLength; b1pQ`qt  
} CV$],BM  
} at!Y3VywG  
l?Y_~Wuw  
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//启动子线程 *?QE2&S:  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 3QI?[R.  
for(int i=0;i<nStartPos.length;i++) %xwIt~Y  
{ )Fd HV;K  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), rQ4*k'lA:  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 4fh^[\  
nStartPos,nEndPos,i); 0s#vwK13  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); }MR1^  
fileSplitterFetch.start(); 7;.xc{  
} -Z4{;I[Q@  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), +u@aJ_^
 
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); X.O
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// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 2c<&eX8"  
nEndPos = " + nFileLength); $=sXAK9   
// fileSplitterFetch[nPos.length-1].start(); IUGz =%[  
A>VI{  
?6Cz[5\  
//等待子线程结束 rdJm{<  
//int count = 0; |5I'CNi\  
//是否结束while循环 xy+QbDT  
boolean breakWhile = false; "O+5R(XT  
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while(!bStop) _2fkb=2@  
{ 0,*%vG?Q  
write_nPos(); qP!eJ6[Nh"  
Utility.sleep(500); P ]N [y  
breakWhile = true; Jxf~&!zR  
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;vhyhP.oM  
for(int i=0;i<nStartPos.length;i++) A6<C-1 N}j  
{ He0=-AR8  
if(!fileSplitterFetch.bDownOver) O<9~Kgd8h  
{ !DjvsG1x  
breakWhile = false; `\=Gp'&Q+  
break; g}&hl"j  
} z2ms^Y=j  
} v/uO&iQw5  
if(breakWhile) t<uYM  
break; %v5R#14[n  
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//count++; #gQ
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//if(count>4) qv 3^5d  
// siteStop(); Q_*_?yf  
} 5OM?3M  
z;]CmR@Ki  
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System.err.println("文件下载结束！"); /4=-b_2Y~  
} Ocg"M Gb  
catch(Exception e){e.printStackTrace ();} L^kp8
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} VeiElU3  
u]C`6)>  
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//获得文件长度 >QQ(m\a$  
public long getFileSize() -y) ,Y |  
{ kg5ev8  
int nFileLength = -1; k>4qkigjc  
try{ 5G}6;UY  
URL url = new URL(siteInfoBean.getSSiteURL()); h>S[^ -,  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ofc.zwH  
httpConnection.setRequestProperty("User-Agent","NetFox"); $<@\-vYvr@  
!Gs} tiMH  
}pNX@C#De  
int responseCode=httpConnection.getResponseCode(); Z{-Lc68  
if(responseCode>=400) xIbMs4'iEx  
{ XR# ;{p+b  
processErrorCode(responseCode); 8$P>wCK\l  
return -2; //-2 represent access is error KM?1/KZ/~  
} 4C_c\;d  
.;/L2Jv  
&!.HuRiuC  
String sHeader; iCG`3(xL  
!jX4`/n2  
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for(int i=1;;i++) `hh9"Ws%  
{ $FM' 3%B[  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); e&Y0}oY  
//Utility.log(in.readLine()); A//?6OJx?  
sHeader=httpConnection.getHeaderFieldKey(i); dFW=9ru+MQ  
if(sHeader!=null) c|p,/L09L  
{ O_@2;iD^^  
if(sHeader.equals("Content-Length")) V}8$p8#<@  
{ kka"C]!  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); pck>;V  
break; -<f/\U  
} =6%|?5G  
} ,krS-.  
else ~&G4)AM  
break; w*LbH]l<-  
} ,cHU)j  
} j\
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catch(IOException e){e.printStackTrace ();} `"y`AY/N  
catch(Exception e){e.printStackTrace ();} )na&"b
J  
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Utility.log(nFileLength); _g
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return nFileLength; jp<VK<s]  
} &~~s6   
f@z*3I;  
@ RR\lZ  
//保存下载信息（文件指针位置） Hhv$4;&X  
private void write_nPos() ," R>}kPli  
{ mBl7{w;Iv  
try{ /A(NuB<Pq  
output = new DataOutputStream(new FileOutputStream(tmpFile)); pG yRX_;  
output.writeInt(nStartPos.length); &sOM>^SA
D  
for(int i=0;i<nStartPos.length;i++) H~9=&p[Q  
{ F-0UdV  
// output.writeLong(nPos); %xg"Q
|  
output.writeLong(fileSplitterFetch.nStartPos); 'Ji+c  
output.writeLong(fileSplitterFetch.nEndPos); /8eW@IO.F  
} jXIE
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output.close(); s44iEh=V(I  
} {yq8<?  
catch(IOException e){e.printStackTrace ();} |-kEGLH[*V  
catch(Exception e){e.printStackTrace ();} 'U)8rR  
} !IAKVQ  
+WF.wP?y  
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//读取保存的下载信息（文件指针位置） @-6?i)  
private void read_nPos() 7:o+iP46  
{ c^S&F9/U*  
try{ :C%47qv  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 0|C[-ppr  
int nCount = input.readInt(); a$+#V=bA  
nStartPos = new long[nCount]; |=3 *;}  
nEndPos = new long[nCount]; Z=9dMND  
for(int i=0;i<nStartPos.length;i++) @hT;Bo2G]  
{ <xF?~7  
nStartPos = input.readLong(); eTZ`q_LfI1  
nEndPos = input.readLong(); 7Po/_%  
} jOl1_  
input.close(); 3wNN<R  
} 6Bdyf(t  
catch(IOException e){e.printStackTrace ();} Yq;&F0paK  
catch(Exception e){e.printStackTrace ();} tc/jY]'32  
} \X opU"  
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private void processErrorCode(int nErrorCode) rk|a'&  
{ 0*{p Oe/u  
System.err.println("Error Code : " + nErrorCode); ZOHRUm  
} {G.{ad  
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}rxFS <j  
//停止文件下载 mt.,4  
public void siteStop() v<fWc9
71  
{ 2$Y3[$  
bStop = true; }q x(z^  
for(int i=0;i<nStartPos.length;i++) b
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fileSplitterFetch.splitterStop(); 0C7"3l  
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} 73#9NZR  
} GD/nR4$  
//负责部分文件的抓取 c$.T<r)Z  
**FileSplitterFetch.java {r X5  
*/ 7x:F!0:  
package NetFox; gU*I;s>  
"lb\c  
CCwK8`%  
import java.io.*; '|+=B u  
import java.net.*; 9&[\*{  
m&{rBz0  
1 pYsjo~  
public class FileSplitterFetch extends Thread { n7'<3t  
dR?5$V(  
c{ZqQtfM  
String sURL; //File URL ^W{eO@  
long nStartPos; //File Snippet Start Position 3pzOt&T|w  
long nEndPos; //File Snippet End Position /XC;.dLA#  
int nThreadID; //Thread's ID  K oL%}u&  
boolean bDownOver = false; //Downing is over ol1AD: Ho  
boolean bStop = false; //Stop identical [kQ"6wh8  
FileAccessI fileAccessI = null; //File Access interface KN|'|2/|  
/Ir 7 DZK  
| eK,Td%  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ~n)]dFy  
{ + >Fv*lux  
this.sURL = sURL; W'8J<VBD  
this.nStartPos = nStart; P/HHWiD`D  
this.nEndPos = nEnd;
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nThreadID = id; | H5Ync[s  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 LjX&',  
} 4_Tb)?L+:  
">rsA&hN-  
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public void run() R#rh  
{ B&to&|jf  
while(nStartPos < nEndPos && !bStop) K>`m_M"LA  
{ B/[hi%~  
* ,|)~$=>  
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try{ pvK \fSr  
URL url = new URL(sURL); )2   
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); @|JPE%T   
httpConnection.setRequestProperty("User-Agent","NetFox"); /6?tgr  
String sProperty = "bytes="+nStartPos+"-"; t;bZc s  
httpConnection.setRequestProperty("RANGE",sProperty); U!3uaz'  
Utility.log(sProperty); @*AYm-k  
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InputStream input = httpConnection.getInputStream(); pRb+'v&_k  
//logResponseHead(httpConnection); _S[Rvb1e   
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byte[] b = new byte[1024];
}Etd#">  
int nRead; 
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while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop)
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{ bF8xQ<i~Y  
nStartPos += fileAccessI.write(b,0,nRead); t/EMBfLc  
//if(nThreadID == 1) 4rGO8R  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); k1@ A'n  
} "m<eHz]D  
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Utility.log("Thread " + nThreadID + " is over!"); pfT`WT  
bDownOver = true; 'IqK M  
//nPos = fileAccessI.write (b,0,nRead); E:LQ!  
} UlLM<33_)  
catch(Exception e){e.printStackTrace ();} t8a@L(J$  
} HCn]#  
} D+@/x{wX2  
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//打印回应的头信息 !D|pbzQc8  
public void logResponseHead(HttpURLConnection con) 6#lC(ko'  
{ 0wa!pE"  
for(int i=1;;i++) UVQa af  
{ m}'t'l4 c  
String header=con.getHeaderFieldKey(i); ]R3pBC"Jv  
if(header!=null) \p=W4W/  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); JCU3\39}  
Utility.log(header+" : "+con.getHeaderField(header));  h(N9RJ}  
else E]U3O>hf  
break; <PuB3PEvV  
} Qi'WV9ke  
} h1UlLy8  
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public void splitterStop() TF iM[  
{ {dr&46$p  
bStop = true; Hr8$1I$=  
} ff5 Lwf{{  
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} K1wN9D{t'  
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/* -L4G WJ~.-  
**FileAccess.java A(@gv8e[H^  
*//文件访问(定位，写) D``NQ`>A  
package NetFox; 8KELN(o$ 7  
import java.io.*; i,b7Ft:F&  
/5'<w(  
LU IT=+  
public class FileAccessI implements Serializable{ o_KcnVQ\  
Z6/~2S@  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 V<7K!<g)b  
RandomAccessFile oSavedFile; eYX_V6c
 
long nPos; OFL+Q~~C  
0<]!G|;|  
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public FileAccessI() throws IOException huD\dmQ:]  
{ _x|8U'|Ce  
this("",0); EKS<s82hF&  
} WUK.>eM0  
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public FileAccessI(String sName,long nPos) throws IOException I%b:Z  
{ _M4v1Hr48  
oSavedFile = new RandomAccessFile(sName,"rw"); @`+$d=rO`  
this.nPos = nPos; D}/.;]w<[&  
oSavedFile.seek(nPos); \ui~n:aWJ  
} }b\q<sNE{  
7<'i#E~  
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public synchronized int write(byte[] b,int nStart,int nLen) w,#W&>+&  
{ 0]w[wc <  
int n = -1; #2'&=?J1r  
try{ ^V,/4u  
oSavedFile.write(b,nStart,nLen); b0=AQ/:  
n = nLen; !J(,M)p!  
} *rKv`nva5  
catch(IOException e) _$_CR\$  
{ )w?$~q  
e.printStackTrace (); RIqxM  
} c(g^*8Pb  
}`FC
_
_  
Uk ;.Hrt.  
return n; Wv/5#
_  
} 1% %Tm"  
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} lc(iy:
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/* PCnJ2  
**SiteInfoBean.java Guc^gq}  
*/ %9)J-B  
package NetFox; w7V W  
`;2`H, G'  
0nnq/u^  
public class SiteInfoBean { buyz>ICP  
(\Zo"x;(  
.u3W]5M|  
private String sSiteURL; //Site's URL +%$V?y (  
private String sFilePath; //Saved File's Path F>R)~;Ja  
private String sFileName; //Saved File's Name &c ~)z\$  
private int nSplitter; //Count of Splited Downloading File <"%h1{V  
\1_&?(pU  
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public SiteInfoBean() T5+b{qA  
{//nSplitter的缺省值为5 D|#(zjl@  
//default value of nSplitter is 5  Jl,x~d  
this("","","",5); ,Gx=e!-N5  
} [6N39G$  
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- & r{%7  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 
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{ E zUjt)wF  
sSiteURL= sURL; G<1mj!{Vp  
sFilePath = sPath; PyE<`E  
sFileName = sName; a8$pc>2E  
this.nSplitter = nSpiltter; 
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P .(X]+  
} .JjuY'-Q  
'J$NW  
{4*%\?c,n  
public String getSSiteURL() .?NAq[H%  
{ _?<Fc8F  
return sSiteURL; XE\bZc  
} Q)&Ztw<  
x|5/#H  
Pw{+7b$  
public void setSSiteURL(String value) 0l*/_;wo  
{ u1<kdTxA N  
sSiteURL = value; |JQ05nb  
} EZV$1pa  
)cXc"aj@s  
wS4wED&a  
public String getSFilePath() x]T;W&s  
{ ZS]e}]Zwp  
return sFilePath; +a;j>hh  
} =c'LG   
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public void setSFilePath(String value) gE~31:a^  
{ ,zaveQ~l  
sFilePath = value; e
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} 0M p>X  
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public String getSFileName() xB#E&}Ho  
{ Xs/hqIXB  
return sFileName; -_(!  
} xAflcY>Ozs  
19_F\32  
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public void setSFileName(String value) |%}?*|-  
{ 4w,}1uNEf  
sFileName = value; Bv3v;^  
} Gex^\gf  
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public int getNSplitter() "M tQj}  
{ U&NOf;h$  
return nSplitter; 7~&Y"&  
} ~oI49Q&{  
uH#NJoRO  
?#'
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public void setNSplitter(int nCount) )Jc>l;G(M  
{ 8"@<s?0\"  
nSplitter = nCount; -:QyWw/d  
} h$!qb'|  
} DCm;dh  
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/* &P;x<7h$t?  
**Utility.java SCo9[EJ  
*/ A28w/=e7  
package NetFox; I4hr5M3  
#\jPBLc  
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public class Utility { k91Y"_&  
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public Utility() 1^,rS  
{ (T^aZuuS  
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R =jK3yfw  
} -{<%Wt9  
FUH1Z+9  
//线程睡眠 j04Q3d \f  
public static void sleep(int nSecond) HCP Be2  
{ 7yc:=^ )  
try{ i"b*U5k  
Thread.sleep(nSecond); V=c&QPP  
} kTzZj|l^\  
catch(Exception e) 7fVVU+y  
{ V +hV&|=  
e.printStackTrace (); {S}/LSNB  
} cB<
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} MF1u8Yl:0  
4Qw!YI#40$  
//日志 H'P
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public static void log(String sMsg) E/am^ TO`  
{ 5/(Dh![l  
System.err.println(sMsg); OZ-F+#d  
} SsaF><{5R  
E1>3[3  
4b(iGLrt0  
public static void log(int sMsg) f[z#
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{ z*R"917  
System.err.println(sMsg); Wl*\kQ}U  
} IX3r$}4  
} ^EB}e
15"  
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/* wwF20  
**TestMethod.java 2;q6~Y,  
*/ wp@c;gK7  
package NetFox;  u2DsjaL  
%7{
6>6%  
DO0["O74  
public class TestMethod { Z,
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{yJ{DU?%Y  
fc M~4yP?  
public TestMethod() ;z&p(e  
{ ///xx/weblogic60b2_win.exe =7$YBCuF  
try{ }g`A*y;t  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); R=E )j^<F  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); / ]I]  
SiteFileFetch fileFetch = new SiteFileFetch(bean); h'N,oDB)  
fileFetch.start(); /at#[Pw~01  
} nc`[fy|}  
catch(Exception e){e.printStackTrace ();} ]qrO"X=  
d`2VbZC`  
6~}=? sX4  
} $biCm$a  
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b|4h2iuM  
public static void main(String[] args) 6 Iup4sP  
{ 9g>ay-W[(  
new TestMethod(); ty(F;M(  
} /Cwt4.5  
} YRB,jwne  
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