http断点续传简单实现（java)

/* YnzhvE  
**SiteFileFetch.java b!7*bFTt  
*/ AUm"^-@x#>  
package NetFox; c0
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import java.io.*; .BR2pf|R  
import java.net.*; Ip0~  
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/Jjub3>Q  
public class SiteFileFetch extends Thread { ;|.^_Xs  
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SiteInfoBean siteInfoBean = null; //文件信息Bean wMB. p2  
long[] nStartPos; //开始位置 ?9Eshw2  
long[] nEndPos; //结束位置 <GbF4\ue  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 S~9K'\vO  
long nFileLength; //文件长度 3:Mq40]x  
boolean bFirst = true; //是否第一次取文件 w@&4dau  
boolean bStop = false; //停止标志 _bi]Bpxf  
File tmpFile; //文件下载的临时信息 %8_bh8g-  
DataOutputStream output; //输出到文件的输出流 qW1d;pt  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） (|<e4HfZL  
public SiteFileFetch(SiteInfoBean bean) throws IOException <,r|*pkhp~  
{ %MQU&H9[  
siteInfoBean = bean; s\k4<d5  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); H6Mqy}4W  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); E,S[3+  
if(tmpFile.exists ()) 6V"|  
{ 3++}4%w  
bFirst = false; R aVOZ=^-  
read_nPos(); hmRnr=2N  
} =ZE]jmD4P  
else Df\~ ZWs!  
{ csceu+IA  
nStartPos = new long[bean.getNSplitter()]; ;#F/2UgHB  
nEndPos = new long[bean.getNSplitter()]; #mI{D\UR  
} 5/vfmDt3'G  
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} A{[joo  
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public void run() )U?Tmh  
{ u3"0K['3  
//获得文件长度 ?s=O6D&   
//分割文件 Vq'\`$_  
//实例FileSplitterFetch *Kpk1  
//启动FileSplitterFetch线程 KW* 2'C&  
//等待子线程返回 {`FkiB` i  
try{ SXYH#p  
if(bFirst) yqEX0|V%  
{ X"4:#s  
nFileLength = getFileSize(); B-oQ 9[~  
if(nFileLength == -1) fgiOYvIS2m  
{ 
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System.err.println("File Length is not known!"); RZ(*%b<C  
} %h}Qf&U_  
else if(nFileLength == -2) TzaR{0 1  
{ WR&>AOWAD  
System.err.println("File is not access!"); F/ZB%;O9  
} ae1?8man  
else zn,y'},  
{ "!ZQ`yl  
for(int i=0;i<nStartPos.length;i++) HHT_}_?  
{ R&>G6jZ?8  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); <G9HVMiP  
} .!fhy[%o:D  
for(int i=0;i<nEndPos.length-1;i++) :y/1Jf'2f  
{ 03ol6y )C  
nEndPos = nStartPos[i+1]; #ujry.m  
} J`E,
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nEndPos[nEndPos.length-1] = nFileLength; `D44I;e^1;  
} q*L>MV  
} (Dy6I;S  
"!V-@F$@N  
R`[jkJrc  
//启动子线程 B]KR*  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; {iGy@?d)zt  
for(int i=0;i<nStartPos.length;i++) a
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{ Dq [f  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), F@8G,$  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), N('=qp9  
nStartPos,nEndPos,i); [>2iz  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); s6q6)RD"  
fileSplitterFetch.start(); I_1(jaY  
} I7@|{L1|FB  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), jR1o<]
?  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); J0ysZ]  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", lOp7rW]$  
nEndPos = " + nFileLength); Oe)d|6=  
// fileSplitterFetch[nPos.length-1].start(); &kR*J<)V  
8t1XZ  
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//等待子线程结束 \;!}z3Ww  
//int count = 0; J?wCqA  
//是否结束while循环 h23"<  
boolean breakWhile = false; TpAE9S  
-w dbH`2Z"  
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while(!bStop) WE{fu{x  
{ XIGz_g;#'w  
write_nPos(); H*m3i;"4p\  
Utility.sleep(500); ~+A(zlYr~  
breakWhile = true; -wh?9?W  
h
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for(int i=0;i<nStartPos.length;i++) l&/V4V-  
{ GM~Ek]9C%  
if(!fileSplitterFetch.bDownOver) z#[PTqD-_  
{ L@5j? N?F  
breakWhile = false; t)4><22of  
break; ]<3n;*8k?  
} HzMr  
} 9{GEq@`7  
if(breakWhile) |erG cKk  
break; yTxrbE  
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)+ V)]dS@%  
//count++; o=nF.y  
//if(count>4) qj7}]T_  
// siteStop(); &G|^{!p/G  
} x5(6U>-Y  
Y&XO:jB  
0h=}BCb+i  
System.err.println("文件下载结束！"); WYUel4Z  
} (GW"iL#.  
catch(Exception e){e.printStackTrace ();}  [HEljEv  
} /E39Z*  
y}F;~H~P  
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//获得文件长度 ;!+-fn4C  
public long getFileSize() %lnVzGP  
{ b9xvLR8  
int nFileLength = -1; l(y,lK=YP1  
try{ )ZW[$:wA  
URL url = new URL(siteInfoBean.getSSiteURL()); \ xJ_)r  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); YMU2^,3  
httpConnection.setRequestProperty("User-Agent","NetFox"); %/4_|.8u  
]vflx^<?  
xZ]QT3U+  
int responseCode=httpConnection.getResponseCode(); +n%d,Pz  
if(responseCode>=400) @DNwzdP  
{ Y#5v5  
processErrorCode(responseCode); IAHQT<]  
return -2; //-2 represent access is error Hl#?#A5  
} T,oZaJ<  
*mJ\Tzc)  
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String sHeader; f<{f/lU@  
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for(int i=1;;i++) i'QR-B&Z  
{ .iC!Ttr  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); N/!(`Z,  
//Utility.log(in.readLine()); ]$,3vYBf  
sHeader=httpConnection.getHeaderFieldKey(i); oF~+L3&X  
if(sHeader!=null) :4r{t?ytXw  
{ |ms.  
if(sHeader.equals("Content-Length")) lhC^Upqw  
{ GJ{XlH  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); I&6M{,rnM  
break; r;9 V7
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} {4$aA*  
} Q!!u=}GYK  
else %a?\y_a=b  
break; n
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} I 6'!b/  
} p/qu4[Mm  
catch(IOException e){e.printStackTrace ();} P6I<M}p  
catch(Exception e){e.printStackTrace ();} (!PsK:wc  
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Utility.log(nFileLength); 0v,fY2$c  
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8OMMV,QF  
return nFileLength; AQ?;UDqU  
} nMJ(tQ  
f5Hv![x  
>"+ho  
//保存下载信息（文件指针位置） 5\EnD,y  
private void write_nPos() R,s}<N$  
{ r1Hh @sxn  
try{ lWn}afI  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 6V"uovN2  
output.writeInt(nStartPos.length); T/.UMw  
for(int i=0;i<nStartPos.length;i++) O^!Bc}$  
{  "D'rsEh  
// output.writeLong(nPos); !9{hbmF#  
output.writeLong(fileSplitterFetch.nStartPos); )MF 4b][  
output.writeLong(fileSplitterFetch.nEndPos); :-WNw n  
} 2q(gWhcj  
output.close(); }4T`)  
} yk'L_M(=  
catch(IOException e){e.printStackTrace ();} sYfm]Faz  
catch(Exception e){e.printStackTrace ();} )vUS).;S`  
} VJP
#  
JeN]sK)8x  
% H<@Y$r  
//读取保存的下载信息（文件指针位置） &Dt=[yqeG  
private void read_nPos() m] yUcj{F  
{ .^2.h  
try{ ZXN`8!]&  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); <5"&]! .  
int nCount = input.readInt(); &8pGq./lr=  
nStartPos = new long[nCount];
+_{cq@c  
nEndPos = new long[nCount]; {P,hH~!  
for(int i=0;i<nStartPos.length;i++) %gQUog  
{ V'gJtF  
nStartPos = input.readLong(); lQiw8qD  
nEndPos = input.readLong(); &Z3%UOY  
} 8f1M
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input.close(); Bd 0oA )i  
} kBLFK3i  
catch(IOException e){e.printStackTrace ();} 6"o=`Sq  
catch(Exception e){e.printStackTrace ();} c&P/v
#U_  
} 1V9AnzwX  
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private void processErrorCode(int nErrorCode) k<P`
 
{ *~YdL7f)J  
System.err.println("Error Code : " + nErrorCode); /CH]'u^j  
} a0+q^*\d\R  
f_$hK9I  
x[$KZGK+GL  
//停止文件下载 a6gPJF[Jo  
public void siteStop() m+(g.mvK>  
{ # S/n3  
bStop = true; _!VtM#G[  
for(int i=0;i<nStartPos.length;i++) ~-[!>1!%  
fileSplitterFetch.splitterStop(); 5Po:$(  
+$#<gp"  
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} "O-X*>?f  
} EADN   
//负责部分文件的抓取 #t;]s<  
**FileSplitterFetch.java xMNQT.A  
*/ O9zMD8  
package NetFox; Dn@ZS_f  
!H@HgJ -  
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import java.io.*; 9-V'U\}L  
import java.net.*; /t`,7y3T  
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public class FileSplitterFetch extends Thread { .>#O'Z&q9  
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4`)r1D!U  
String sURL; //File URL c-5AI{%bl6  
long nStartPos; //File Snippet Start Position \b%c_e  
long nEndPos; //File Snippet End Position FNuE-_  
int nThreadID; //Thread's ID y2#"\5dC  
boolean bDownOver = false; //Downing is over 0;@>jo6,!  
boolean bStop = false; //Stop identical k7Qs#L  
FileAccessI fileAccessI = null; //File Access interface (_!I2"Q*  
vb?.`B_>&  
9od*N$  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException c_S~{a44Ud  
{ #;~HoOK*#  
this.sURL = sURL; dt@c,McN|Q  
this.nStartPos = nStart; XVqkw@Ia4!  
this.nEndPos = nEnd; @8>bp#x/1  
nThreadID = id; _k26(rdI@-  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 .D ^~!A  
} =R'O5J  
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_tX=xAO9  
public void run() Y2XxfZj  
{ AEaN7[PQx|  
while(nStartPos < nEndPos && !bStop) |nWEuKHy  
{ ?T_MP"  
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De^
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try{ [520!JhZY  
URL url = new URL(sURL); \eNB L[  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); M;Pry3J  
httpConnection.setRequestProperty("User-Agent","NetFox");
lq"X_M$  
String sProperty = "bytes="+nStartPos+"-"; -z+,j(@  
httpConnection.setRequestProperty("RANGE",sProperty); 8U(o@1PT  
Utility.log(sProperty); [tof+0Y6  

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InputStream input = httpConnection.getInputStream(); ZIa,pON  
//logResponseHead(httpConnection); MTCfs~}m  
tB"9%4](  
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byte[] b = new byte[1024]; 2b"Dk
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int nRead; ,8Po _[  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) .l_
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{ p*,T~(A6  
nStartPos += fileAccessI.write(b,0,nRead); ssx#|InY  
//if(nThreadID == 1) B7[d^Y60B  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); OqIXFX"  
} X*@
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iLZY6?_^  
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Utility.log("Thread " + nThreadID + " is over!"); /P@%{y  
bDownOver = true; 6QY;t:/<  
//nPos = fileAccessI.write (b,0,nRead); ap )B%9  
} ur8+k4]\"  
catch(Exception e){e.printStackTrace ();} M Zz21H  
} FMeBsI9pL  
} p>+9pxx~U  
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U< Xdhgo?
 
//打印回应的头信息 -)oUb=Lk{  
public void logResponseHead(HttpURLConnection con) g?v
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{ ').)0;  
for(int i=1;;i++) KH;~VR8"/  
{ z``wqK  
String header=con.getHeaderFieldKey(i); $\h-F8|JMX  
if(header!=null) F!EiF&[\J  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); iOURS  
Utility.log(header+" : "+con.getHeaderField(header)); WM ?a1j  
else `L`+`B  
break; $N)G:=M!s  
} N5=BjXSAg  
} i>YQ<A1  
Pn">fWRCx  
}l7+W4~  
public void splitterStop() X%5eZ"1{x  
{ F=e9o*z  
bStop = true; 50N4J  
} (~^fx\
-S  
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} ~< bpdI0  
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/* NAvR^"I~  
**FileAccess.java  '/.Dxib  
*//文件访问(定位，写) b/z-W`gw  
package NetFox; Bxm,?=h  
import java.io.*; 1^WGJ"1  
T(7`$<TQ  
DQXUh#t\(]  
public class FileAccessI implements Serializable{ ResU5Ce~  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 pd'0|  
RandomAccessFile oSavedFile; yv[j Pbe  
long nPos;  lln"c  
j HHWq>=d  
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public FileAccessI() throws IOException +H2Jhgi  
{ /e'3\,2_  
this("",0); QF"7.~~2  
} <xy@%  
Q*smH-Sw  
PdcIHN  
public FileAccessI(String sName,long nPos) throws IOException l'+3 6  
{ &n k)F<  
oSavedFile = new RandomAccessFile(sName,"rw"); V*4Z.3/E5  
this.nPos = nPos; i?6&4  
oSavedFile.seek(nPos); !wy _3a
 
} dE7x SI  
9*)&hhBs,  
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public synchronized int write(byte[] b,int nStart,int nLen) ;l@94)@0  
{ ;}46Uc#WS  
int n = -1; JtL>mH  
try{ ~R!1{8HP  
oSavedFile.write(b,nStart,nLen); NfgXOLthM  
n = nLen; v/`D0g-uX)  
} (u,)v_Oo]a  
catch(IOException e) c?A$Y?|9  
{ ?Z#N9Z~\  
e.printStackTrace (); OsgPNy0  
} !Z!)$3bB  
*d1BpR%  
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return n; rQjk   
} G$<(>"Yr~$  
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} Q]k<Y  
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/* [
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**SiteInfoBean.java ;.>*O oe&  
*/ /%T/@y  
package NetFox; !m@cTB7i   
fzSkl`K}  
/7AHd ;  
public class SiteInfoBean { BPY7O  
;KL7SM%g4  
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private String sSiteURL; //Site's URL NdXHpq;  
private String sFilePath; //Saved File's Path CsO!Y\'FY  
private String sFileName; //Saved File's Name RM2Ik_IH[l  
private int nSplitter; //Count of Splited Downloading File w 3t,S3!  
6V;Dcfvi  
/UCBoQ$/]  
public SiteInfoBean() HsCL%$k  
{//nSplitter的缺省值为5 b;i*}4h!  
//default value of nSplitter is 5 :@L7RZ`_  
this("","","",5); x5lVb$!G  
} 3q]0gU&??  
/vQ)$;xf#  
|+cz\+  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Ua1&eCZi  
{ D;,p?]mgO~  
sSiteURL= sURL;
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sFilePath = sPath; {]CZgqE{  
sFileName = sName; 46?z*~*G  
this.nSplitter = nSpiltter; 529;_|  
#VQZ"7nI@  
i$Y#7^l%k  
} 1[egCC\Mo_  
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uYC^&siS<s  
public String getSSiteURL() 9{pT)(Wnb  
{ YD4I2'E  
return sSiteURL; %['NPs%B  
} 1mFH7A($  
,N$Q']Td  
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public void setSSiteURL(String value) #$WnMJ@  
{ v`h>5#_[  
sSiteURL = value; (B#FLoK  
} dle\}Sy=  
]OpGD5jZ  
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public String getSFilePath() igu1s}F  
{ qnP4wRpr  
return sFilePath; MW
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} X}#vt?mu  
MTYV~S4/  
^#5'` #t  
public void setSFilePath(String value) HNkOPz+d&8  
{ r/h\>s+N  
sFilePath = value; }s2CND  
} :(q4y-o6  
;D'm=uOl  
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public String getSFileName() FBE|pG7  
{ +Xg:*b9So  
return sFileName; c!@|yE,  
} x8lBpr  
~&:-c v  
?y|&Mz'XJ(  
public void setSFileName(String value) Zbo4{.#  
{ ZK4V-?/[6  
sFileName = value; p5]W2i.,  
} ivo3pibk%  
2I:P}!  
091m$~r*  
public int getNSplitter() .{gDw  
{ ;(K/O?nrJ  
return nSplitter; P$'PB*5d|  
} gwB,*.z  
#X]*kxQ<  
T4x%3-4;  
public void setNSplitter(int nCount) .XgY&5Qk  
{ ^E%R5JN  
nSplitter = nCount; w&@tP^`  
} :h,}yBJ1L  
} KXMf2)pa  
.*NPoW4Kv  
&pK0>2  
/* oDS7do  
**Utility.java #~Xj=M%
 
*/ H[w';u[%  
package NetFox; FqyxvL.  
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public class Utility { Z6B$\Q5Od  
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public Utility() %nJo:/  
{ #2|biTJ  
/ 8O=3  
+M.BMS2A<l  
} e R[B0;c  
(x% 4*  
//线程睡眠 FVNTE+LW  
public static void sleep(int nSecond) lDBAei3iB  
{ v2gk1a&  
try{ RaLV@>jPm  
Thread.sleep(nSecond); V+D<626o  
} q4X(_t  
catch(Exception e) Lapeh>1T  
{ ,g'>
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e.printStackTrace (); =XYc2.t  
} 7Z9'Y?[m  
} =LY`K#  
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//日志 z-3.%P2g  
public static void log(String sMsg) #Fo#f<bp  
{ *Mg@j;+5s  
System.err.println(sMsg); Z@Q/P(t  
} ;4dFL\KU  
>r X$E<B\  
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public static void log(int sMsg) yk!K5  
{ f4,|D |  
System.err.println(sMsg); pC,Z=+:  
} bGB$a0  
} >aVtYp B  
@}PXBU   
M_+W5Gz<  
/* 8wO4;  
**TestMethod.java vr"Pr4z4i  
*/ k:7Gb7\  
package NetFox; a:GM|X  
WnGi;AGH=1  
~u!V_su]GY  
public class TestMethod { #oiU|>3Y  
W=g'Xu!|!2  
9:g]DIL  
public TestMethod() ho6hjhS|u  
{ ///xx/weblogic60b2_win.exe QSzht$8  
try{ / j "}e_Q  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); [< g9jX5  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); s%rmfIp"  
SiteFileFetch fileFetch = new SiteFileFetch(bean); MrUjqv6a[  
fileFetch.start(); Y6Y"fb%K  
} C(h<s e?  
catch(Exception e){e.printStackTrace ();} i@D4bd9lR  
#?\(l%  
7MZH'nO  
} |_g7k2oLY  
T9J&^I  
E;`^`T40  
public static void main(String[] args) lq.]@zlSO  
{ +VQD'  
new TestMethod(); QoUdTIIL  
} 'y>Y*/  
} SHSfe{n  
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