http断点续传简单实现（java)

/* ^v!im\ r  
**SiteFileFetch.java b!]0mXU  
*/ )@qup _M@  
package NetFox; (a}
  
import java.io.*; P=^#%7J/l  
import java.net.*; QP%kL*=8  
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public class SiteFileFetch extends Thread { tQ~<i %;  
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SiteInfoBean siteInfoBean = null; //文件信息Bean m*!f%}T  
long[] nStartPos; //开始位置 ^$IZLM?E~  
long[] nEndPos; //结束位置 14D7U/zer  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 *w/WHQ`xI  
long nFileLength; //文件长度 /u)Rppu  
boolean bFirst = true; //是否第一次取文件 :B=8_M  
boolean bStop = false; //停止标志 NGD*ce"w  
File tmpFile; //文件下载的临时信息 Q0cY/'>4  
DataOutputStream output; //输出到文件的输出流 x48'1&m  
7B(bH8  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） `4%;qLxngP  
public SiteFileFetch(SiteInfoBean bean) throws IOException `\jTpDV_W  
{ h.V]fS
 
siteInfoBean = bean; YN@6}B#1  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); NLQE"\#a  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 'e]HP-Y<  
if(tmpFile.exists ()) @ EmGexLPM  
{ d9Z&qdxTKq  
bFirst = false; ZCQ<%f  
read_nPos(); 90s;/y(  
} T|@#w%c''  
else Cqgk  
{ %f(S'<DhC  
nStartPos = new long[bean.getNSplitter()]; JzMZB"Z?  
nEndPos = new long[bean.getNSplitter()]; pDq#8*q+v  
} #9`rXEz  
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} #SQvXMT  
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public void run() tqf&N0*  
{ 0||"r&:X  
//获得文件长度 4;C*Fa  
//分割文件 dC`tN5  
//实例FileSplitterFetch _1sMYhI  
//启动FileSplitterFetch线程 L)F1NuR  
//等待子线程返回 $;Vc@mYGW;  
try{ BWUt{,?KU  
if(bFirst) j1YH9T#|D  
{ a@#Q:O)4  
nFileLength = getFileSize(); ]U,CKJF%/  
if(nFileLength == -1) fxDj+Q1p  
{ )nwZ/&@  
System.err.println("File Length is not known!"); qL| 5-(P  
} B6bOEPQ  
else if(nFileLength == -2) H`m:X,6}
 
{ oYz!O]j;a  
System.err.println("File is not access!"); tAqA^f*{  
} ~BZXt7DE  
else j z~[5m}J  
{ QCOLC2I  
for(int i=0;i<nStartPos.length;i++) ja[OcR-tX  
{ Vkr
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); '{[!j6wt\  
} y"^yYO  
for(int i=0;i<nEndPos.length-1;i++) Di*]ab  
{ (0i'Nb"  
nEndPos = nStartPos[i+1]; n%/i:Whs  
} ImIqD&a-h  
nEndPos[nEndPos.length-1] = nFileLength; 1^C|k(t  
} _>Pk8~m  
} iJdP>x  
H9RGU~q4s[  
3Y z]8`C  
//启动子线程 5W+{U8\  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; +UxI{,L  
for(int i=0;i<nStartPos.length;i++) {A|bBg1!  
{ =fl%8"%N&  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), SLkuT`*  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), XHsd-  
nStartPos,nEndPos,i); }^"0T-ua  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); %}C9
  
fileSplitterFetch.start(); &1wpGJqm  
} rA,CQypo  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Xv0F:1  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1);
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// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", +W9]ED  
nEndPos = " + nFileLength); %3M95UZ2  
// fileSplitterFetch[nPos.length-1].start(); TPHYz>D]  
|olNA*4  
0p-#f|ET  
//等待子线程结束 F
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//int count = 0; IX9K.f  
//是否结束while循环 0[/vQ+O]2  
boolean breakWhile = false; -kl;!:'.3  
A 4j<\xL  
3gpo %  
while(!bStop)
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{ sAi&A9"*   
write_nPos(); `(!NYx  
Utility.sleep(500); j 1(T )T  
breakWhile = true; *>k!hq;
j  
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for(int i=0;i<nStartPos.length;i++) )1f+ld%R  
{ o(qEkR:4kd  
if(!fileSplitterFetch.bDownOver) c3] C:t+  
{ XLm@etf  
breakWhile = false; I}+;ME|<2  
break; $jG4pPG  
} :#{-RU@PS  
} (/K5!qh  
if(breakWhile) D`Gt  
break; ^agj4$  
=EW3&+Lt  
vX+.e1m  
//count++; qD-fw-,:  
//if(count>4) [ ?iqqG.  
// siteStop(); ^av6HFQ  
} G>%AZr{M  
?*H9-2W@  
@9 )}cg  
System.err.println("文件下载结束！"); mb\
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} txq~+'A:+  
catch(Exception e){e.printStackTrace ();} e.l!3xY2'  
} L/?]^!.  
3OP.12^  
p
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//获得文件长度  (
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public long getFileSize() !v9lk9SV  
{ )TU<:V  
int nFileLength = -1; h
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try{ tPU-1by$  
URL url = new URL(siteInfoBean.getSSiteURL()); Uoji@  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); s<vs:jna  
httpConnection.setRequestProperty("User-Agent","NetFox"); t
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vXdZmYrC  
X|
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int responseCode=httpConnection.getResponseCode(); 5ZK&fKeCF  
if(responseCode>=400) \}JrFc%O  
{ #Qh>z%Mn^3  
processErrorCode(responseCode); dl0FQNz8@B  
return -2; //-2 represent access is error -$JO8'TP  
} >w.'KR0L  
`T"rG}c  
c@R; /m:R  
String sHeader; \a))  
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8>NwCjN  
for(int i=1;;i++) !msNEE@[  
{ {%b }Z2  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Jdj?I'XtY  
//Utility.log(in.readLine()); |QMA@Mx  
sHeader=httpConnection.getHeaderFieldKey(i); oM,- VUr  
if(sHeader!=null) 2z_2.0/3  
{ 3c#s|qW  
if(sHeader.equals("Content-Length")) XErUS80  
{ |g-b8+.=]  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); e1
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break; n ~,tQV  
} m\vmY  
} pSfYu=#f  
else ? \m3~6y  
break; @{d\j]Nw  
} <7)Fh*W@  
} s0C:m  
catch(IOException e){e.printStackTrace ();} mR+Jws'  
catch(Exception e){e.printStackTrace ();} *1A&'T2  
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Utility.log(nFileLength); /ty?<24ko  
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return nFileLength; S8vV!xO  
} UE :HMn6  
XOy2lJ/  
w%a8XnW]1  
//保存下载信息（文件指针位置） GABQUmtH  
private void write_nPos() PJLR<9  
{ {fDTSr?/  
try{ vF4]ux&  
output = new DataOutputStream(new FileOutputStream(tmpFile)); |L
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output.writeInt(nStartPos.length); #X`8dnQZ  
for(int i=0;i<nStartPos.length;i++) aeP[+I9  
{ cpZc9;@IC  
// output.writeLong(nPos); S%mfs!E>  
output.writeLong(fileSplitterFetch.nStartPos); Ug%_@t/?  
output.writeLong(fileSplitterFetch.nEndPos); jQh^WmN  
} 5[gh|I;D  
output.close(); !EBY@ Y1  
} 0Scm?l3  
catch(IOException e){e.printStackTrace ();} \9{F5Sz  
catch(Exception e){e.printStackTrace ();} 6GL=)0Ah  
} T!2=*~A  
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3 hKBc0  
//读取保存的下载信息（文件指针位置） }< 5F  
private void read_nPos() C~4PE>YtTv  
{
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try{ zsXpA0~3s  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); E JK0  
int nCount = input.readInt(); #8h;Bj  
nStartPos = new long[nCount]; r8/l P}(F  
nEndPos = new long[nCount]; aM=D84@  
for(int i=0;i<nStartPos.length;i++) ?GT@puJS-  
{ Di5(9]o2  
nStartPos = input.readLong(); [A2`]CE<@  
nEndPos = input.readLong(); (Ddp|a"b  
} .12aUXo(  
input.close(); </"4 zD|  
} w:i:~f .  
catch(IOException e){e.printStackTrace ();} )?aaBaN$  
catch(Exception e){e.printStackTrace ();} C$yq\C+I  
} 1zxq^BI  
0CExY9@Wq  
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private void processErrorCode(int nErrorCode) ,*svtw:2')  
{ !Ng=Yk>3  
System.err.println("Error Code : " + nErrorCode); ~P*4V]L^  
} /t%u"dP"T~  
O9M{  ).  

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//停止文件下载 9N8I ip]w  
public void siteStop() M8&}j  
{ MCTsi:V>+  
bStop = true; 'lz"2@4{  
for(int i=0;i<nStartPos.length;i++) kOL'|GgK  
fileSplitterFetch.splitterStop(); DKL@wr}8  
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} N)2f7j4C&  
} L1{GL #qV  
//负责部分文件的抓取 5z}w}zdg  
**FileSplitterFetch.java 23F/\2MSG  
*/ u.XQ&  
package NetFox; p=Q0!!_r  
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import java.io.*; LNYKm~cN  
import java.net.*; =='Td[  
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public class FileSplitterFetch extends Thread { D;}xr_  
pKUP2m`MW  
%r\n%$@_  
String sURL; //File URL 2
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long nStartPos; //File Snippet Start Position Dim> 7Wbh  
long nEndPos; //File Snippet End Position "r4AY  
int nThreadID; //Thread's ID N2r/ho}8  
boolean bDownOver = false; //Downing is over [lzN !!B!  
boolean bStop = false; //Stop identical op2Of<{h  
FileAccessI fileAccessI = null; //File Access interface F9"w6;hh  
x
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException \>. LW9  
{ 1/+C5Bp*  
this.sURL = sURL; }|OaL*|u  
this.nStartPos = nStart; >SF Uy\3  
this.nEndPos = nEnd; 1$/MrPT(b  
nThreadID = id; &F *'B|n  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 zET^T5>:  
} B(g_Gm<  
Q#I"_G&{  
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public void run() K7knK  
{ 4S"\~><  
while(nStartPos < nEndPos && !bStop) \W5O&G-C  
{ `3H4Ajzcc  
} p FQRSOZ  
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try{ 96cJ8I8  
URL url = new URL(sURL); {6
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); GYxM0~:$k  
httpConnection.setRequestProperty("User-Agent","NetFox"); 8
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String sProperty = "bytes="+nStartPos+"-"; ]B"'}%>ez  
httpConnection.setRequestProperty("RANGE",sProperty); z}QwP~Z  
Utility.log(sProperty); H(c72]@Vg  
lf{e[!ML'  
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InputStream input = httpConnection.getInputStream(); k %e^kej  
//logResponseHead(httpConnection); <P[T!gST  
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byte[] b = new byte[1024]; XgN` 7!Z  
int nRead; h+p*=|j`  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) @+vXMJ$  
{ >WJf=F`_H  
nStartPos += fileAccessI.write(b,0,nRead); K5ZC:Ks  
//if(nThreadID == 1) (s<Dd2&.H  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ;7]u!Q  
} iXu]e;6  
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Utility.log("Thread " + nThreadID + " is over!"); 6*4's5>?D  
bDownOver = true; 0]KraLu"N  
//nPos = fileAccessI.write (b,0,nRead);  Amr[wx  
} ]xC#rwHUC  
catch(Exception e){e.printStackTrace ();} Ac2(O6  
} q5h*`7f  
} `g8E1-]l  
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fH`P[^N  
//打印回应的头信息 =ph&sn$;L  
public void logResponseHead(HttpURLConnection con) ,g-EW jN  
{ rk+#GO{  
for(int i=1;;i++) ~7~~S*EQ  
{ ](tx<3h  
String header=con.getHeaderFieldKey(i); {2/LRPT  
if(header!=null) <DKS
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//responseHeaders.put(header,httpConnection.getHeaderField(header)); m }a|FS  
Utility.log(header+" : "+con.getHeaderField(header)); Y$N)^=7  
else />¬$>  
break; B]m@:|Q  
} 4c oJRqf=  
} 0&qr  
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public void splitterStop() Qy<[7  
{ IDkWGh  
bStop = true; /27Jev
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} {Q+gZcu  
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} vS\%3A4^+5  
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/*  tz#gClo  
**FileAccess.java mRB  
*//文件访问(定位，写) xe7O/',pa=  
package NetFox; FMkOo2{  
import java.io.*; >fH=DOz$&  
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public class FileAccessI implements Serializable{ `cPywn@uGZ  
REZJ}%}/  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 S3L~~X/=  
RandomAccessFile oSavedFile; d(g^M1m  
long nPos; F+E|r6'i  
*f,DhT/P  
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public FileAccessI() throws IOException z0|&W&&D  
{ O+%WR  
this("",0); W@yJAQ  
} c/B'jPt  
66^ycZCH  
&1+X\c+tb  
public FileAccessI(String sName,long nPos) throws IOException '9c2Q/  
{ jiF?fX@  
oSavedFile = new RandomAccessFile(sName,"rw"); U4 13?
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this.nPos = nPos; 'J,T{s1J  
oSavedFile.seek(nPos); !61Pl/uQ  
} !LkWzn3  
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public synchronized int write(byte[] b,int nStart,int nLen) p>_;^&>&  
{ Vy_2
.  
int n = -1; JG9`h#  
try{ VmzbZTup  
oSavedFile.write(b,nStart,nLen); 5{n*"88  
n = nLen; 5K|"\  
} Ed9Z9  
catch(IOException e) }I@L}f5N  
{ )DYI .  
e.printStackTrace (); "t^URp3  
} hJzxbr <  
<hwy*uBrD  
a0Ik`8^`  
return n; O?<&+(uMTT  
} _EF&A-kX|u  
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} + >cBVx6  
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/* ^ wY[3"{  
**SiteInfoBean.java <>m }}^  
*/ 
!QDQ_  
package NetFox; 7\ nf:.  

9CCkqB/  
)5|I_PXB  
public class SiteInfoBean { ='TE,et@d  
6sa"O89  
~G27;Npy  
private String sSiteURL; //Site's URL Z}|(FRVk  
private String sFilePath; //Saved File's Path %*#n d  
private String sFileName; //Saved File's Name ;<0LXYL;  
private int nSplitter; //Count of Splited Downloading File >5Wlc$bc  
SZJ$w-<z  
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public SiteInfoBean() Mwgu93?  
{//nSplitter的缺省值为5 lo'W1p  
//default value of nSplitter is 5 q5>v'ZSo  
this("","","",5); F@R1:M9*  
} 3s"0SLS4  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) tDr#H!2 3  
{ WcC?8X2  
sSiteURL= sURL; JWA@+u*k  
sFilePath = sPath; `# sTmC)  
sFileName = sName; F4Y@ B  
this.nSplitter = nSpiltter; %T7nO%p  
5s{ABJ\@V  
0euuT@_$  
} 5MzFUv0)  
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v=('{/^~>  
public String getSSiteURL() 8p-=&cuo\@  
{ H5D*|42  
return sSiteURL; -48vJR*tC  
} pIbdN/z  
wO2_DyMm@  
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public void setSSiteURL(String value) aTf`BG{kw  
{ "TH6o:x  
sSiteURL = value; Bo5ZZY  
} 8( btZt  
z"*/mP2  
7z~_/mAI  
public String getSFilePath() -R{V-   
{ y1=NF  
return sFilePath; c*UvYzDZL  
} qH['09/F6  
`Y?87f:SP  
<, 3ROo76  
public void setSFilePath(String value) c^`]`xiX  
{ %7O?JI[  
sFilePath = value; uI
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} k
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#2iD'>bQ  
wp7!>%s{  
public String getSFileName() xUfbW;;]UU  
{ V]EtwA  
return sFileName; 5s?Hxn  
} _{jjgQJ5  
"`asFg  
1He{v#  
public void setSFileName(String value) @AYRiOodi  
{ J~(Wf%jM~  
sFileName = value; 7^T^($+6s&  
} zS]8V?`  
7)%+=@  
67y Tvr@a  
public int getNSplitter() US  
{ hQNe;R5  
return nSplitter; ;l}- Z@! /  
} ;O<9|?  
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public void setNSplitter(int nCount) 5{$LsL  
{ OxGE
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nSplitter = nCount; X>?b#Eva  
}
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} ^T~gEv  
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/* /s
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**Utility.java >&!RWH9*q  
*/ vy,&N^P  
package NetFox; Bvt@X   
;60.l!  
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public class Utility { }KhjlPhx  
bq
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public Utility() u{z``]  
{ `]Ppau  
0P>OJYFr'  
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} 34!dYr%  
2DD:~Tbi  
//线程睡眠 Nm):9YQ/  
public static void sleep(int nSecond) 1N2,mo?2  
{ _Jv 9F8v  
try{ &Z?ut*%S  
Thread.sleep(nSecond); 6oSQQhge  
} c%*($)#  
catch(Exception e) l^J75$7  
{ OGiV{9U  
e.printStackTrace (); 8P: Rg%0)  
} *Ei|fe$sa  
} 0q\7C[R_  
`"@X.}\  
//日志 ~ d^<_R  
public static void log(String sMsg) ;6 +}z~  
{ .Wi{lt  
System.err.println(sMsg); {G*A.$-d  
} >u%]6_[  
PCnQ_A-Q  
PM":Vd/  
public static void log(int sMsg) a{Esw`  
{ ;IK[Y{W/  
System.err.println(sMsg); Jx#k,Z4  
} . |*f!
w}5  
} }bU8G '  
)EyI0R]5  
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/* sS TPMh  
**TestMethod.java aAu>Tn86D.  
*/ 8vk..!7n}  
package NetFox; ,7,g%?_P
 
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e4OeoQ@ >  
public class TestMethod { _ .i3,-l)  
>\ST-7
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public TestMethod() ~"Gf<3^y+  
{ ///xx/weblogic60b2_win.exe d7Ur$K\=y  
try{ 1xf=_F0`&  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); \n0Oez0z!B  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); A~nf#(!^]  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 56hA]O29O  
fileFetch.start(); NvjJb-u  
} ?t@v&s  
catch(Exception e){e.printStackTrace ();} h;lirvO|  
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avp;*G}  
} ydv
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public static void main(String[] args) a:YI"*S  
{ !2:3MbtR  
new TestMethod(); iAMtejw  
} 6{d6s#|%  
} U-wLt(Y<  
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