http断点续传简单实现（java)

/* CL )%p"[x  
**SiteFileFetch.java g!\QIv1D  
*/ 4NI'(#l  
package NetFox; 6<+8}`@B>G  
import java.io.*;
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import java.net.*; vS2(Q0+TZi  
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public class SiteFileFetch extends Thread { "|\94  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ]svw CPu C  
long[] nStartPos; //开始位置 zM)M_L  
long[] nEndPos; //结束位置 I>!|3ElT  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 .$OjUlzr-H  
long nFileLength; //文件长度 5 5a@)>h  
boolean bFirst = true; //是否第一次取文件 + p'\(Z(  
boolean bStop = false; //停止标志  @}Pw0vC  
File tmpFile; //文件下载的临时信息 s?HsUD$b  
DataOutputStream output; //输出到文件的输出流 r@
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） sgR 9d  
public SiteFileFetch(SiteInfoBean bean) throws IOException zEAx:6`c  
{ 4bWfx_0W  
siteInfoBean = bean; }el,^~  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); &4[<F"W>47  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); `c>A
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if(tmpFile.exists ()) )~G8 LZ  
{ NCp%sGBmG  
bFirst = false; x9TuweG  
read_nPos(); cFe V?a  
} ;,R[]B01u  
else E=3#TBd  
{ \?[O,A  
nStartPos = new long[bean.getNSplitter()]; Jr|K>  
nEndPos = new long[bean.getNSplitter()]; YALyZ.d  
} w:n(pLc<  
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} Y{`3`Pg&N  
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public void run() &qG?[R{  
{ |YJ$c@  
//获得文件长度 rUGZjLIGqz  
//分割文件 -<H ri5  
//实例FileSplitterFetch 6Uch0xha!  
//启动FileSplitterFetch线程 p^}L  
//等待子线程返回 ^"PfDTyA  
try{ :A,O(   
if(bFirst) e?|d9;BO  
{ ~>lOl/n5  
nFileLength = getFileSize(); nqBG]y aI  
if(nFileLength == -1) RT1{+:l  
{ [9'|7fdU  
System.err.println("File Length is not known!"); -Cg`x=G;z  
} @263)`9G  
else if(nFileLength == -2) !^n1  
{ eUi> Mp  
System.err.println("File is not access!"); PV5-^Y"v  
} &IIJKn|_  
else D:+)uX}MOf  
{ >B@i E  
for(int i=0;i<nStartPos.length;i++) R994R@gz  
{ MYKs??]Y1  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); "h^A]t;qe  
} ,ZsYXW  
for(int i=0;i<nEndPos.length-1;i++) 7g{g}  
{ Cij$GYkv  
nEndPos = nStartPos[i+1]; >aNbp  
} B:B0p+$I  
nEndPos[nEndPos.length-1] = nFileLength; nD^{Q[E6=  
} ]t
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} JI28O8  
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9[6G8;<D&  
//启动子线程 r_{)?B  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; j=`y  @~  
for(int i=0;i<nStartPos.length;i++) qiF@7i  
{ V.O<|tl.  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), "it`X B.  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), UwvGr h  
nStartPos,nEndPos,i); *##QXyyg  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); u?LW+o  
fileSplitterFetch.start(); "H wVK  
} BT y]!%r'  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), v4nvZ6  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 0(Yh~{  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", oAIY=z  
nEndPos = " + nFileLength); *93l${'  
// fileSplitterFetch[nPos.length-1].start(); Tw`
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we6+2  
//等待子线程结束 (CKhY~,/u  
//int count = 0; Vu_7uSp,)  
//是否结束while循环 My'9S2Y8nv  
boolean breakWhile = false; ^K1~eb*K  
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while(!bStop) xMO[3D&D  
{ g] 7{5  
write_nPos(); /y+;g{  
Utility.sleep(500); vWPM:1A  
breakWhile = true; 'Qp&,xK  
\}]=?}(  
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for(int i=0;i<nStartPos.length;i++) Y3 Pz00x  
{ :pL1F)-*  
if(!fileSplitterFetch.bDownOver) r_qncy,F  
{ ^=4I|+P,6.  
breakWhile = false; {ziYd;Ys1  
break; =rf)yp-D  
} (Von;U  
} W>aQ tT  
if(breakWhile) :8\*)"^E  
break; 1[fkXO{  
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//count++; L@d]RMNv  
//if(count>4) Q{ |+3!!'  
// siteStop(); -$sl!%HO%  
} K#m\qitb  
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System.err.println("文件下载结束！"); xr7-[)3Q$  
} 0{U]STj  
catch(Exception e){e.printStackTrace ();} tWCv]*  
} JN;TGtB^p  
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//获得文件长度 L~?,6  
public long getFileSize() ArEH%e  
{ )sY$\^'WY  
int nFileLength = -1; 9^b7jw  
try{ e$p1Th*|]4  
URL url = new URL(siteInfoBean.getSSiteURL()); Sh~ 8jEk  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); JWUv H  
httpConnection.setRequestProperty("User-Agent","NetFox"); 1%]{0P0?[  
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int responseCode=httpConnection.getResponseCode(); f//j{P[  
if(responseCode>=400) oJ4mxi@|#  
{ n{qa]3  
processErrorCode(responseCode); "R\\\I7u  
return -2; //-2 represent access is error ~]6Oz;~<3  
} 0IT20.~  
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String sHeader; {=pP`HD0  
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for(int i=1;;i++) V;[__w  
{ y$r?t0
 
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); G}9bCr,  
//Utility.log(in.readLine()); Zo}\gg3  
sHeader=httpConnection.getHeaderFieldKey(i); (A
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if(sHeader!=null) g O\f:Pg  
{ |aOnV,}  
if(sHeader.equals("Content-Length")) }{w_>!ee  
{ +i q+  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); $J;=Ux)$  
break; Q%AS;(d  
} 2jrX  
} am$-sh72  
else =`7)X\i@z  
break; C7fi1~  
} !kHyLEV  
} 8YJqM,t5)  
catch(IOException e){e.printStackTrace ();} u6bB5(s`&  
catch(Exception e){e.printStackTrace ();} s6eq?1l3  
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Utility.log(nFileLength); 4o)\DB?!  
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return nFileLength; W&~iO   
} 6
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//保存下载信息（文件指针位置） Tr}$Pb1  
private void write_nPos() S9ak '  
{ 9{]r+z:  
try{ sP8-gkkor  
output = new DataOutputStream(new FileOutputStream(tmpFile)); "#eNFCo7k  
output.writeInt(nStartPos.length); pFv[z':&Q  
for(int i=0;i<nStartPos.length;i++) >/OXC+=^4  
{ _ /28Cw  
// output.writeLong(nPos); {]/Jk07  
output.writeLong(fileSplitterFetch.nStartPos); Q,M/R6i-  
output.writeLong(fileSplitterFetch.nEndPos); 2dV\=vd  
} #9W5
 
output.close(); PUFW^"LV  
} W<Vzd4hR  
catch(IOException e){e.printStackTrace ();} w]+BBGYQKb  
catch(Exception e){e.printStackTrace ();} ?
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} ZC\.};.  
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//读取保存的下载信息（文件指针位置） S;AnpiBM8  
private void read_nPos() &0<R:K?>N  
{ BoiIr[ (  
try{ kvO`]>#;$?  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); $xn%i\  
int nCount = input.readInt(); (=&bo p  
nStartPos = new long[nCount]; dW=D]  
nEndPos = new long[nCount]; {i7Fu+xZj  
for(int i=0;i<nStartPos.length;i++) nY5n%>8  
{ F#37Qv  
nStartPos = input.readLong(); cI4qgV  
nEndPos = input.readLong(); Z=/L6Zb  
} 'r?HL;,q  
input.close(); lt(-,md  
} kk\zZC <  
catch(IOException e){e.printStackTrace ();} 9
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catch(Exception e){e.printStackTrace ();} uL
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} Vwh&^{Eh  
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private void processErrorCode(int nErrorCode) p$!+2=)gY  
{ -9<yB  
System.err.println("Error Code : " + nErrorCode); ,tv9+n@x  
}
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//停止文件下载 A =Az[  
public void siteStop() @.]K6qC  
{ ", Rw%_  
bStop = true; MKhL^c-  
for(int i=0;i<nStartPos.length;i++) 0-MasI&b  
fileSplitterFetch.splitterStop(); +mQC:B7>  
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} g#<?OFl  
} DBh/V#* D  
//负责部分文件的抓取 &T/9yW[L  
**FileSplitterFetch.java -0J<R;cVs  
*/ AiHDoV+-  
package NetFox; LGgx.Z  
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import java.io.*; Va[dZeoy  
import java.net.*; <Phr`/  
)*<d1
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public class FileSplitterFetch extends Thread { snzH}$Ls  
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String sURL; //File URL G;#t6bk  
long nStartPos; //File Snippet Start Position DdZ_2B2  
long nEndPos; //File Snippet End Position `YU:kj<6  
int nThreadID; //Thread's ID &#\7w85$  
boolean bDownOver = false; //Downing is over 5}^08Xl  
boolean bStop = false; //Stop identical i2R]lE8  
FileAccessI fileAccessI = null; //File Access interface UU~;B  
D@1
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ia.B@u1/  
{ z8[|LF-dx  
this.sURL = sURL; h] TVi$J  
this.nStartPos = nStart; P##(V!YR  
this.nEndPos = nEnd; u2m{Y
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nThreadID = id; ~ilBw:L-3  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 .?)oiPW#  
} <+JFal  
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public void run() Jt^JE{m9%  
{ 7(iRz  
while(nStartPos < nEndPos && !bStop) hQLx"R$  
{ f6A['<%o  
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try{ ?U[nYp}"v  
URL url = new URL(sURL); $W]guG  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); TZ_'nB~  
httpConnection.setRequestProperty("User-Agent","NetFox"); *1]k&#s  
String sProperty = "bytes="+nStartPos+"-"; _[Wrd?Z  
httpConnection.setRequestProperty("RANGE",sProperty); 4U1fPyt  
Utility.log(sProperty); 4!W?z2ly~R  
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InputStream input = httpConnection.getInputStream(); bH]!~[  
//logResponseHead(httpConnection); @MH]s [{o\  
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byte[] b = new byte[1024]; D_kzR  
int nRead; XQ y|t"Vq>  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) on&=%tCAL  
{ *wyLX9{:  
nStartPos += fileAccessI.write(b,0,nRead); [4yQbqe;  
//if(nThreadID == 1) #EK8Qe_  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Mp}NUQHE  
} d(tf:@  
PS;*N8  
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Utility.log("Thread " + nThreadID + " is over!"); 3sIM7WD?  
bDownOver = true; m8A1^ R  
//nPos = fileAccessI.write (b,0,nRead); k(Xv&Zn  
} TmH13N]  
catch(Exception e){e.printStackTrace ();} hds4_  
} eTHh  
} 6u3(G j@  
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//打印回应的头信息 ai9,4  
public void logResponseHead(HttpURLConnection con) *%+buHe  
{ f=Y9a$.:M  
for(int i=1;;i++) ;P#*R3   
{ tO;W?g  
String header=con.getHeaderFieldKey(i); HBGA lZ  
if(header!=null) Upen/1bA  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); m3e49 bP  
Utility.log(header+" : "+con.getHeaderField(header)); LZ:\V)5+  
else ZO$T/GE6%  
break; 5ml}TSMu'  
} @y&,e,3!  
} X}^gmu<Vla  
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public void splitterStop() bd;f@)X  
{ <OB~60h"  
bStop = true; %*}f<k{6  
} <7) 6*u  
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2 -8:qmP(  
} fbkjK`_q  
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/* C{^@.8:  
**FileAccess.java iP_Xr~w  
*//文件访问(定位，写) ^<+heX  
package NetFox; ^Z+D7Q  
import java.io.*; >1zzDd_  
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fdW={}~  
public class FileAccessI implements Serializable{ 6GvnyJ{[  
o)WSMV(&f  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ,Yz+?SmSZ&  
RandomAccessFile oSavedFile; =1Jo-!{{  
long nPos; VHNiTp  
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public FileAccessI() throws IOException NQ=YTRU  
{ Dw,f~D$+ic  
this("",0); kJFHUR  
} E
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public FileAccessI(String sName,long nPos) throws IOException _gh7_P^H=d  
{ 3/05ee;|  
oSavedFile = new RandomAccessFile(sName,"rw"); Bk<P~-I  
this.nPos = nPos; pQ8+T|0x  
oSavedFile.seek(nPos); GrC")Z|3u  
} 7C^ nk z  
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h (2k;M^s  
public synchronized int write(byte[] b,int nStart,int nLen) gp2)35  
{ {*Pp^r  
int n = -1; " z{w^k  
try{ _r'M^=yx[  
oSavedFile.write(b,nStart,nLen); 3J<,2
 
n = nLen; {Wo7=a
R  
} 1fZ:^|\  
catch(IOException e) 1YL5 ![T  
{ bux-t3g7+  
e.printStackTrace (); k*^W lCZ3  
} #w6CL  
"-%H</  
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return n; iSHl_/I<  
} U)8]pUI+/P  
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} |e>-v  
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/* |&7,g  
**SiteInfoBean.java oJ:J'$W(  
*/ AF6'JxG7  
package NetFox; ba13^;fm#  
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public class SiteInfoBean { 67?5Cv  
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v'tk:Hm1  
private String sSiteURL; //Site's URL *2F}e4v  
private String sFilePath; //Saved File's Path zdE^v{}|  
private String sFileName; //Saved File's Name /+msrrpD  
private int nSplitter; //Count of Splited Downloading File $}fA;BP  
2Fi*)\{  
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public SiteInfoBean() (i8t^  
{//nSplitter的缺省值为5 %3j5Q   
//default value of nSplitter is 5 )VC) }  
this("","","",5); PQ>JoRs  
} (6nw8vQ  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) F04Etf 2k  
{ R8l9i2  
sSiteURL= sURL; xJCpWU3wM  
sFilePath = sPath; {W]jVh p  
sFileName = sName; AK HH{_  
this.nSplitter = nSpiltter; g:U ul4  
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} O [/~V=  
iq$/6!t  
/eQn$ZRP,  
public String getSSiteURL() V_!i KEU  
{ @V)WJ{  
return sSiteURL; q]x@q  
} n9fk{"y'G  
,"o\_{<z  
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public void setSSiteURL(String value) I?QKd@  
{ K@m^QioMj  
sSiteURL = value; N"TD$NrK\  
} OjZ@_V:  
PW}.`  
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public String getSFilePath() EeO{G*pq  
{ W=
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return sFilePath; 9[`6f8S_$  
} :9}*p@  
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n[@Ur2&)  
public void setSFilePath(String value) 9!LAAE`  
{ jJ|;Nwm<[  
sFilePath = value; w8qI7/  
} ,v"A}g0"  
:Lx]`dSk  
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public String getSFileName() *D,T}N  
{ E'Bt1u  
return sFileName; amRtFrc|  
} W4<}w-AoEp  
*q RQN+%  
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public void setSFileName(String value) {% P;O ?  
{ YdFCYSiS  
sFileName = value; Y*Pr

 
} 8/:\iPk0  
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public int getNSplitter() x?3p3[y  
{ DxlX-  
return nSplitter; {)mlXo(On  
} ,O}zgf*H;  
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public void setNSplitter(int nCount) -8IiQRS  
{ g=)@yZ3>v  
nSplitter = nCount; ;bX{7j  
} .qZ<ROZ  
} b|NEU-oy  
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+ '`RJ,K+[  
/* 5GKz@as8  
**Utility.java 9g7T~|P  
*/ }^H_|;e1p  
package NetFox; *b&|  
7%hMf$KQ  
sd
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public class Utility { 7$'ja  
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public Utility() _/Hu'9432  
{ L,i-T:Z~=  
}sFHb[I &  
IoC,\$s,  
} [K5afnq`  
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//线程睡眠 S7bSR?~L[  
public static void sleep(int nSecond) 8:f(PN  
{ v[m>;Ubg&  
try{ [Y[|:_+5  
Thread.sleep(nSecond); fA8 ,wy|>  
} ?g 3sv5\u  
catch(Exception e) #u~8Txt  
{ R#0UwRjeF  
e.printStackTrace (); %n^]1R#  
} #r\uh\Cy  
} =#W6+=YN8  
v
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//日志 L(.5:&Y=`  
public static void log(String sMsg) k20tn ew  
{ |K]tJi4fz  
System.err.println(sMsg); dQ<EDtap  
} >">-4L17m  
139_\=5|U/  
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public static void log(int sMsg) hGsYu)  
{ },l3N K  
System.err.println(sMsg); }q^CR(h (R  
} MD+Q_  
} +7=3[K  
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/* #soWX_>  
**TestMethod.java #(OL!B  
*/ bS*9eX=K  
package NetFox; >6c{CYuT  
#<{sP0v*  
cG.4%Va@s_  
public class TestMethod { +B
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Lx.X#n.]T  
8IO4>CMkv  
public TestMethod() HM`;%0T0(  
{ ///xx/weblogic60b2_win.exe 2gA6$s7  
try{ _T1|_9b  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); &Mol8=V)  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); q:fkF^>  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 8q_nOG
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fileFetch.start(); `On%1%k8  
} :V&#Oo  
catch(Exception e){e.printStackTrace ();} -LUKYG
BK  
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} $. Ih-  
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public static void main(String[] args) m}rUc29cS,  
{ XOU 9r(  
new TestMethod(); 4h-tR  
} X4gs{kx}|  
} +5voAx!  
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