http断点续传简单实现（java)

/* u,So+%  
**SiteFileFetch.java B[GC@]HE  
*/ p%>sc  
package NetFox; 8%#8PLB2  
import java.io.*; X]
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import java.net.*; O
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public class SiteFileFetch extends Thread { #dUKG8-HJ  
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SiteInfoBean siteInfoBean = null; //文件信息Bean BX0lk  
long[] nStartPos; //开始位置 ]O"f%  
long[] nEndPos; //结束位置 M/=36{,w-  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ,r
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long nFileLength; //文件长度 /B@{w-N  
boolean bFirst = true; //是否第一次取文件 a31
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boolean bStop = false; //停止标志 !Ud'(iGa  
File tmpFile; //文件下载的临时信息 l5{60$g  
DataOutputStream output; //输出到文件的输出流 UrizZ5a  
0]|`*f&p;  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） @F<{/|P  
public SiteFileFetch(SiteInfoBean bean) throws IOException Wn(!6yid  
{ U]sAYp^$  
siteInfoBean = bean; SWV*w[X<X  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); U.Mfu9}#:  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); )OV0YfO  
if(tmpFile.exists ()) [! $NTt_  
{ iH }-  
bFirst = false; Xkhd"Axi  
read_nPos(); a.Z@Z!*  
} noxJr/A]  
else eut2x7Z(c  
{ o:AfEoH"~  
nStartPos = new long[bean.getNSplitter()]; %;k Hnl  
nEndPos = new long[bean.getNSplitter()]; `s CwgY+  
} qg oB}n%  
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} k
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public void run() Ik0g(-d  
{ (?|M'gZ  
//获得文件长度 \"a{\E,{;  
//分割文件 aV'bI  
//实例FileSplitterFetch q*3OWr  
//启动FileSplitterFetch线程 {JgY-#R?{(  
//等待子线程返回 gm-[x5O"  
try{ d&j  
if(bFirst) ukSv70Ev  
{ G tI )O}  
nFileLength = getFileSize(); F}nwTras  
if(nFileLength == -1) 7Bp7d/R-  
{ H#SQ>vyAV  
System.err.println("File Length is not known!"); A`Z/B[)  
} M/?,Qii  
else if(nFileLength == -2) uAn}qrqE9  
{ 5daq}hsQs  
System.err.println("File is not access!"); @L3XBV2  
} 2FIL@f|\7z  
else y/Xs+ {x  
{ 'k,2*.A  
for(int i=0;i<nStartPos.length;i++) la3B`p  
{ jzbq{#  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); R@o&c%K"  
}  'o-4'  
for(int i=0;i<nEndPos.length-1;i++)
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{ 0B`X056|"|  
nEndPos = nStartPos[i+1]; *S.U8;*Xj  
} 5?7AzJl>  
nEndPos[nEndPos.length-1] = nFileLength; Du+W7]yCl  
} puC91  
} ;,&cWz  
==dKC;  
MET9rT  
//启动子线程 FH~:&;  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; !T`oHs  
for(int i=0;i<nStartPos.length;i++) Xqf,_I=V  
{ |THpkfW  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), yajdRU  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ` =>}*GS  
nStartPos,nEndPos,i); M13HD/~O  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); VzP az\e  
fileSplitterFetch.start(); -'&/7e6>y  
} [;u#79aE
 
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), MR#*/Iw~  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ))"gWO  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 3:+9H}Q  
nEndPos = " + nFileLength); %_OjmXOfe  
// fileSplitterFetch[nPos.length-1].start(); ^#Ii=K-[^  
I^
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UY',n,  
//等待子线程结束 ^jL '*&l  
//int count = 0; R BYhU55B  
//是否结束while循环 $h#sb4ek  
boolean breakWhile = false; o`bc/3!  
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while(!bStop) mO>L]<O  
{ Pyo|Sgk  
write_nPos(); b:dN )m  
Utility.sleep(500); |toP86  
breakWhile = true; Cr.YSWg)4  
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KF.{
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for(int i=0;i<nStartPos.length;i++) 4{P+p!4  
{ 2cMCZuO  
if(!fileSplitterFetch.bDownOver) L+am-k:T~  
{ 3Ua?^2l  
breakWhile = false; NAR6q{c  
break; :viW  
} (>al-vZ6A  
} }%|ewy9|CW  
if(breakWhile) 2Rk}ovtD[  
break; s2<!Zb4  
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l=~!'1@L}  
//count++; YF5}~M ymF  
//if(count>4) MEDh  
// siteStop(); /F0q8j0  
} PYkhY;*  
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System.err.println("文件下载结束！"); 5hrI#fpOR  
} H"A%mrb  
catch(Exception e){e.printStackTrace ();} MGg(d  
} ]fyfL|(;  
)Qbd/zd\U  
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//获得文件长度 }p)K6!J0  
public long getFileSize() @oXGa>Ru  
{ Y}?8  
int nFileLength = -1; ula
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try{ DR#" 3  
URL url = new URL(siteInfoBean.getSSiteURL()); 5UEZpxnv  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ~7]V^tG  
httpConnection.setRequestProperty("User-Agent","NetFox"); *8}b&4O~  
{r^_g(.q  
:Jd7q.  
int responseCode=httpConnection.getResponseCode(); ^6s im2  
if(responseCode>=400) c!6D{(sfh  
{ U+S=MP }:  
processErrorCode(responseCode); n]4E>/\  
return -2; //-2 represent access is error =xI;D,@S  
} IKD{3cVL  
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String sHeader; F? #3  
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for(int i=1;;i++) RN$vKJk  
{ ,B
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//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); yaUtDC.|  
//Utility.log(in.readLine()); \v2!5z8|  
sHeader=httpConnection.getHeaderFieldKey(i); E>~R P^?Uz  
if(sHeader!=null) z0 "DbZ;d  
{ _7Y h[I4  
if(sHeader.equals("Content-Length")) kCB
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{
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nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); T+Oqd\05.+  
break; 1Bh"'9-!JT  
} ho\1[xS  
} fM=o?w6v  
else Z\!,f.>g  
break; D!j/a!MaKk  
} xl}rdnf}  
}
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catch(IOException e){e.printStackTrace ();} }k^uup*{  
catch(Exception e){e.printStackTrace ();} .;? Bni  
{U5
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Utility.log(nFileLength); dY1t3@E  
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return nFileLength; q<YM,%mgj  
} B%F]K<  
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*$Q>Om]  
//保存下载信息（文件指针位置） iq&3S0  
private void write_nPos() oi #B7  
{ wuq
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try{ (NJ{>@&  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 2#wnJdr6E  
output.writeInt(nStartPos.length); bWe2z~dP  
for(int i=0;i<nStartPos.length;i++) w\buQ6pR)  
{ B,>02EZ  
// output.writeLong(nPos); V DF
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output.writeLong(fileSplitterFetch.nStartPos); ^C>kmo3J  
output.writeLong(fileSplitterFetch.nEndPos); !:(+#  
} qGinlE&\  
output.close(); ~D52b1f  
} }M07-qIX{  
catch(IOException e){e.printStackTrace ();} d4Uw+3ikW  
catch(Exception e){e.printStackTrace ();} j7I=2xnTWu  
} -gn0@hS0  
v+ $3
  
}\a#e^-xQ+  
//读取保存的下载信息（文件指针位置） 'Ru(`" 1|  
private void read_nPos() qCs/sW  
{ I%T+H[,  
try{ pbMANZU[  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); (,Y[2_Zv  
int nCount = input.readInt(); -&/?&{Q0  
nStartPos = new long[nCount]; (i&+=+"wn  
nEndPos = new long[nCount]; XC<fNK  
for(int i=0;i<nStartPos.length;i++) l+ }=D@l  
{ $AK ^E6  
nStartPos = input.readLong(); >y%H2][  
nEndPos = input.readLong(); w2LnY1A  
} y_X6{}Ke  
input.close(); 7[ ovEE54  
} n Kkpp-  
catch(IOException e){e.printStackTrace ();} =s\$i0A2  
catch(Exception e){e.printStackTrace ();} $|$@?H>K  
} >S5J^c  
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private void processErrorCode(int nErrorCode) (5T>`7g8  
{ 0R?1|YnB  
System.err.println("Error Code : " + nErrorCode); (HNc9QVC'W  
} e!u]l  
)5|9EXh  
91R#/i  
//停止文件下载 **q8vhJM  
public void siteStop() fUw:jExz  
{ kowS| c#  
bStop = true; f;E#CjlTL  
for(int i=0;i<nStartPos.length;i++) J*@pM  
fileSplitterFetch.splitterStop(); ^t0!Dbx3SE  
196aYLE  
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} jCqz^5=$  
} 1RAkqw<E  
//负责部分文件的抓取 #Xg;E3BM  
**FileSplitterFetch.java P(T-2Ux6  
*/ 5/.W-Q\pl}  
package NetFox; \h ~_<)  
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import java.io.*; TQ
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import java.net.*; CJ<nUIy'z  
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public class FileSplitterFetch extends Thread { k*1Lr\1  
\M`qaFan5^  
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String sURL; //File URL zTng]Mvx  
long nStartPos; //File Snippet Start Position a`wjZ"}'[  
long nEndPos; //File Snippet End Position [ycX)iM  
int nThreadID; //Thread's ID |/,SNE  
boolean bDownOver = false; //Downing is over "uH>S+%|b  
boolean bStop = false; //Stop identical 0i~U(qoI  
FileAccessI fileAccessI = null; //File Access interface l7QxngWw  
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 +n1!xv]  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException y 4i3m(S  
{ R ]Ev=V'U  
this.sURL = sURL; fe\lSGmf  
this.nStartPos = nStart; :9&c%~7B9  
this.nEndPos = nEnd; }geb959  
nThreadID = id; ,dRaV</2  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 93*csO?Db  
} p%I)&- 8  
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public void run() eo+<@83  
{ V.Hv6  
while(nStartPos < nEndPos && !bStop) N,Y)'s<  
{ Zc7;&cz  
7|}4UXr7y  
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try{ %a/3*vz/I%  
URL url = new URL(sURL); /A9RmTb  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); SVU>q:ab  
httpConnection.setRequestProperty("User-Agent","NetFox"); joY7Vk!<o  
String sProperty = "bytes="+nStartPos+"-"; .SC*!,  
httpConnection.setRequestProperty("RANGE",sProperty); xs= ~N  
Utility.log(sProperty); 7I3_$uF  
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InputStream input = httpConnection.getInputStream(); TpU\IQ  
//logResponseHead(httpConnection); tF;0P\i  
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byte[] b = new byte[1024]; |k.'w<6mb9  
int nRead; ]p!{   
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) xXJ*xYn"}  
{ eiK_JPFA-  
nStartPos += fileAccessI.write(b,0,nRead); b 3x|Dq.  
//if(nThreadID == 1) ^hLr9k   
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); _LJF:E5L  
} Sa g)}6+  
W )FxN,  
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Utility.log("Thread " + nThreadID + " is over!"); #E]K*mE'  
bDownOver = true; zQ,rw[C"W  
//nPos = fileAccessI.write (b,0,nRead); R4p Pt  
} ]-gyXE1.r  
catch(Exception e){e.printStackTrace ();} z0[@O)Sj  
} KF(H >gs  
} 4aO/^Hl  
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$tZ {>!N  
//打印回应的头信息 8lusKww  
public void logResponseHead(HttpURLConnection con) SAP/jD$5]>  
{ N{%7O
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for(int i=1;;i++) Vk{
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{ zYzV!s2^  
String header=con.getHeaderFieldKey(i); 6n]+(=  
if(header!=null) C|ZPnm>f30  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); G)amng/  
Utility.log(header+" : "+con.getHeaderField(header));  sS-dHa  
else 9q"kM  
break; 4l 67B]o  
}
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} <YvXyIs  
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public void splitterStop() Im;%.J  
{ ;e?M;-  
bStop = true; ?[JP[ qS  
} }$_@yt<{W@  
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} 9@|52dz%  
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/* zsp%Cz7T  
**FileAccess.java %7ngAIg  
*//文件访问(定位，写) A-!e$yz>  
package NetFox; {s8c@-'  
import java.io.*; w;lpJB\  
/h>g-zb  
}zGx0Q  
public class FileAccessI implements Serializable{ |.k'?!  
g*YDgY  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 J5{;+ysUMl  
RandomAccessFile oSavedFile; a0|hLqI  
long nPos; V_h&9]RL  
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public FileAccessI() throws IOException s+:|b~  
{ n\+c3  
this("",0); afrF%!  
} `;85Mo:qJ  
#Y=^4U`  
gH//@`6  
public FileAccessI(String sName,long nPos) throws IOException T]tP!a;K  
{
+p%3pnj:K  
oSavedFile = new RandomAccessFile(sName,"rw"); bv4umL /  
this.nPos = nPos; ^L%_kL_7  
oSavedFile.seek(nPos); t\,Y<9{w  
} n{gEIUo
#  
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-`faXFW'  
public synchronized int write(byte[] b,int nStart,int nLen) 9L>?N:%5  
{ COw"6czX/  
int n = -1; T8+[R2_  
try{ `G$>T#Dq  
oSavedFile.write(b,nStart,nLen); ~$y"Ldrp  
n = nLen; QP\9#D~  
} ?oYO !  
catch(IOException e) IAO5li3  
{ 5_(\Cd<#  
e.printStackTrace (); `vBBJ@f4)  
} Wj.t4XG!  
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return n; bB$f=W!m%  
} p]kEH\ sh  
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}#^Cj;  
} 9"P+K.%  
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6 - 3?&+  
/* d]0:r]e  
**SiteInfoBean.java w;,34qbf  
*/ T?RY~GA  
package NetFox; m}l);P^  
<H^jbK  
27!FB@k-  
public class SiteInfoBean { {4S UGo>  
~uhW~bT  
k{2Gq1S{  
private String sSiteURL; //Site's URL 33~MP;  
private String sFilePath; //Saved File's Path >`
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private String sFileName; //Saved File's Name <1*kXTN(  
private int nSplitter; //Count of Splited Downloading File Tf3CyH!k  
I~6) Gk&  
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public SiteInfoBean() RZHfT0*jL  
{//nSplitter的缺省值为5 {.LJ(|(Mz  
//default value of nSplitter is 5 RL}?.'!  
this("","","",5); OJm ]gb7  
} @\?HlGWEf  
/5sn*,  
{8.Zb NEJ  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) >J;TtNE:  
{ /NQrE#pb  
sSiteURL= sURL; We y*\@  
sFilePath = sPath; RsDSsux  
sFileName = sName; ,NGHv?.N  
this.nSplitter = nSpiltter; ~|"Vl<9  
Q^ W,)%  
%V=%ARP|  
} DzR,ou  
<6(0ZO%,C!  
0BXr[%{`  
public String getSSiteURL() eay|>xa2  
{ Un]wP`  
return sSiteURL; 2.Z#\6Vj  
} ^;F/^_  
{<{VJGY7T  
8-<F4^i_i  
public void setSSiteURL(String value) S})f`X9_}  
{ qU#A,%kcV  
sSiteURL = value; .'`aX 7{\  
} u.yR oZ8/!  
i`+w.zJOH8  
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public String getSFilePath() 2B4.o*Q\  
{ TyV~2pcN  
return sFilePath; {H/%2  
} I7_8oq\3D  
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2{j$1EdI@-  
public void setSFilePath(String value) _|\X8o_  
{ 0f5
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sFilePath = value; W/UA%We3+L  
} 0m3hL~0(a  
$TK*w8@:  
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public String getSFileName() "" UyfC[  
{ !Q"L)%)'A  
return sFileName; -Y524   
} }a
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public void setSFileName(String value) p l^;'|=M  
{ ,6]ID1o:y  
sFileName = value; YH58p&up  
} %fF,Fnf2  
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v(;yy{>8"  
public int getNSplitter() ]?]M5rP  
{ Z=8&`  
return nSplitter; 6-\Mf:%B  
} ~+{*KPiD  
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s O#cJAfuu  
public void setNSplitter(int nCount) fDDpR=  
{ <h#7;o  
nSplitter = nCount; o1#3A  
} #)}BY"C%  
} C]Fw*t   
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+7%?p"gEY\  
/* o<A-ETx<  
**Utility.java _1?uAQ3,  
*/ 29grbP  
package NetFox;  B=*0  
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public class Utility { [NE!  
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public Utility() 2W0nA t  
{ @Nb/
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/$%&fo\[  
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} KK 7}q<&i  
=p@2[Uo  
//线程睡眠 8qkQ*uJP  
public static void sleep(int nSecond) eTjPztdJbx  
{ z(c8]Wu#  
try{ 9wCgJ$te  
Thread.sleep(nSecond); %qcCv9  
} {3KY:%6qj  
catch(Exception e) &FmTT8"l  
{ t8Pf~v  
e.printStackTrace (); *JImP9SE  
} mD> J,E  
} f-#:3k*7S  
PI L)(%
X  
//日志 W'9{2h6u(  
public static void log(String sMsg) TAh'u|{u2  
{ H,c1&hb/w  
System.err.println(sMsg); *-*V>ntvT$  
} _886>^b@  
RCfeIHL  
>A{e,&  
public static void log(int sMsg) Z?S?O#FED  
{ kj2qX9Ms  
System.err.println(sMsg); R<1%Gdz  
} waz5+l28  
} d(}? \|  
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2wO8;wiA  
/* Wj3i*x$  
**TestMethod.java [[_>DM  
*/ Z[[*:9rY|  
package NetFox; ag8)^p'9  
b,:^\HKC  
VS4Glx73  
public class TestMethod { .qe+"$K'n  
;^s|n)F#c  
\x$`/  
public TestMethod() mKTF@DED  
{ ///xx/weblogic60b2_win.exe ;fV"5H)U\  
try{ _b>z'4_'  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); vy2<'V*y}  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); \6GNKeN  
SiteFileFetch fileFetch = new SiteFileFetch(bean); V%[t'uh  
fileFetch.start(); fqbWD)L]  
} 0X99D2c  
catch(Exception e){e.printStackTrace ();} jSBz),.XU}  
6t!=k6`1  
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} uB\UIz)e  
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public static void main(String[] args) z z]~IxQ  
{ A]Hz?i  
new TestMethod(); y)LX?d  
} _GY2|x2c  
} cb'Y
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