http断点续传简单实现（java)

/* t.y-b`v  
**SiteFileFetch.java HxSq&j*F  
*/ ~jC+6v  
package NetFox; ];xDXQd  
import java.io.*; qYoB;gp  
import java.net.*;
^G|*=~_  
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public class SiteFileFetch extends Thread { ;3x*pjLG:Q  
b:Z&;A|"{  
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SiteInfoBean siteInfoBean = null; //文件信息Bean y+3+iT@i  
long[] nStartPos; //开始位置 E75/EQ5p]p  
long[] nEndPos; //结束位置 v5>A1\  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 [?%q,>F  
long nFileLength; //文件长度 >)F "lR:o  
boolean bFirst = true; //是否第一次取文件 zD)/QFILy  
boolean bStop = false; //停止标志 ]Hp>~Zvbb  
File tmpFile; //文件下载的临时信息 XeX\u3<D  
DataOutputStream output; //输出到文件的输出流 n{u\t+f  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） B (Ps/  
public SiteFileFetch(SiteInfoBean bean) throws IOException H2H`7 +I,  
{ *Nm$b+  
siteInfoBean = bean; Mg#yl\v  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); I4W@t4bZ  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); !O,Sq/=.  
if(tmpFile.exists ()) _%q~K (::  
{ J
s
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bFirst = false; c {/J.  
read_nPos(); sUF9_W5z  
} ]{oZn5F  
else \yl|*h3  
{ @-}*cQ4u?  
nStartPos = new long[bean.getNSplitter()]; !_vxbfZO  
nEndPos = new long[bean.getNSplitter()]; SE'!j]6jI  
} +D@5zq:5  
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} QF)\\D[  
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public void run() /a'1W/^2  
{ h);^4cU  
//获得文件长度 M?!@L:b[  
//分割文件 ^|H={pd'c0  
//实例FileSplitterFetch y~fKLIoz"  
//启动FileSplitterFetch线程 w9{C"K?u=  
//等待子线程返回 As<B8e]  
try{ +x(#e'6p  
if(bFirst) R*:>h8  
{ V:$+$"|  
nFileLength = getFileSize(); RN[I%^$"  
if(nFileLength == -1) SRwD`FF  
{ #
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System.err.println("File Length is not known!"); T5 (|{-  
} tLBtE!J$[  
else if(nFileLength == -2) #obRr#8  
{ @@)2 12  
System.err.println("File is not access!"); 1>"-!ADm  
} MfP)Pk5  
else PD)"od  
{ G@.MP| 2  
for(int i=0;i<nStartPos.length;i++) x2rAB5r6  
{ < cvh1~>(  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 0V4B Q:v  
} n:,mo}?X  
for(int i=0;i<nEndPos.length-1;i++) e"ehH#i  
{ =5q<_as  
nEndPos = nStartPos[i+1]; d=/0A\O  
} l
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nEndPos[nEndPos.length-1] = nFileLength; Ut;`6t  
} ")T\_ME  
} LWyr  
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//启动子线程 X` zWw_i  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; gv''A"  
for(int i=0;i<nStartPos.length;i++) unLhI0XW  
{ TIWR[r1!  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), (k?HT'3)  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), G3~`]qf  
nStartPos,nEndPos,i); [ QiG0D_'=  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); H"#ITL  
fileSplitterFetch.start(); f#\YX tR,k  
} &EfQ%r}C  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), l~6K}g?  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); %GHGd'KO&  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", KwuucY  
nEndPos = " + nFileLength); Upe}9
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// fileSplitterFetch[nPos.length-1].start(); ]mTBD<3\  
>2'"}np
*  
w G%W{T$  
//等待子线程结束 c+ oi8G  
//int count = 0; TmsIyDcD~  
//是否结束while循环 /|IPBU 5  
boolean breakWhile = false; vrkY7L3\  
/ad9Q~nJ  
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while(!bStop) x4oWZEd  
{ =]Vz=<  
write_nPos(); |A%9c.DG.  
Utility.sleep(500);  lN,?N{6s  
breakWhile = true; j]Jgz<  
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8]ZzO(=@{  
for(int i=0;i<nStartPos.length;i++) .T| }rB<c  
{ 0zaK&]oY0  
if(!fileSplitterFetch.bDownOver) #c^V%  
{ `*C=R  _  
breakWhile = false; +$
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break; [_,as  
} *doNPp)m  
} [9 W@<p  
if(breakWhile) Smr{+m a  
break; |A8@r&  
2cR[~\_9.  
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//count++; IS2cU'  
//if(count>4) hH %>  
// siteStop(); &{}Mds  
} jJy:/!i  
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System.err.println("文件下载结束！"); )cqD">vs  
} CU'JvVe3  
catch(Exception e){e.printStackTrace ();} l~c[}wv  
} CMa6':~  
t`Kbm''d[
 
6b2UPI7m~  
//获得文件长度 @ZjT_  
public long getFileSize() lQn" 6o1  
{
|9CikLX)7  
int nFileLength = -1;  I//=C6  
try{ g.lTNQm$u  
URL url = new URL(siteInfoBean.getSSiteURL()); WYP;s7_  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); %6UF%dbYH`  
httpConnection.setRequestProperty("User-Agent","NetFox"); h>-P
/  
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int responseCode=httpConnection.getResponseCode(); XL
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if(responseCode>=400) {]0e=#hw  
{ $></%S2g  
processErrorCode(responseCode); ?'
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return -2; //-2 represent access is error JMb_00r  
} dftBD  
s]arNaaA  
bSB%hFp=Cp  
String sHeader; SmRlZ!%e  
4,9$udiGY  
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for(int i=1;;i++) fab'\|Y   
{ ,X4e?$7g  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); d2rs+-  
//Utility.log(in.readLine()); asT-=p_ 0.  
sHeader=httpConnection.getHeaderFieldKey(i); -@orIwA&  
if(sHeader!=null) }9~^}99}  
{ I6>J.6luF9  
if(sHeader.equals("Content-Length")) $#Pxf  
{ JK k0f9)  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); &m5zd$6  
break; U7r8FLl  
} nbi7rcT  
} z _!ut  
else B`*,L\LZ*  
break; swKkY`g  
} +vBi7#&  
} Y G+|r  
catch(IOException e){e.printStackTrace ();} Syk)S<  
catch(Exception e){e.printStackTrace ();} \Wbmmd}8  
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Utility.log(nFileLength); :^;c(>u{  
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return nFileLength; Sj9fq*  
} jr6_|(0 i6  
)vp0X\3q`  
1!#85SMx  
//保存下载信息（文件指针位置） %y1!'R:ZW  
private void write_nPos() jc^QWK*q  
{ Lb*KEF%s  
try{ +H)'(<  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Q8p6n  
output.writeInt(nStartPos.length); .Y)[c.,j  
for(int i=0;i<nStartPos.length;i++) !Ok(mgV$/  
{ j8Z,:op  
// output.writeLong(nPos); U1RU2M]v  
output.writeLong(fileSplitterFetch.nStartPos); Q$jEmmm%V[  
output.writeLong(fileSplitterFetch.nEndPos); Up9{aX  
} s#2t\}/  
output.close(); %fS9F^AK  
} 7
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catch(IOException e){e.printStackTrace ();} U|^xr~q!f-  
catch(Exception e){e.printStackTrace ();} $=aO*i  
} @6u/)>rI  
7|rH9Bc{U  
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//读取保存的下载信息（文件指针位置） 20:F$d  
private void read_nPos() IqOg{#sm  
{ .sMs_ 5D  
try{ s**<=M GK  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Fq9YhR  
int nCount = input.readInt(); Y.:R-|W  
nStartPos = new long[nCount]; sI ,!+  
nEndPos = new long[nCount]; $Y/9SD  
for(int i=0;i<nStartPos.length;i++) Jt~Ivn,  
{ hI[} -  
nStartPos = input.readLong(); &2'-v@kK  
nEndPos = input.readLong(); .@1+}0  
} -m@o\9Ic  
input.close(); uuzV,q  
} .*O*@)}Ud  
catch(IOException e){e.printStackTrace ();} L/3A g* ]  
catch(Exception e){e.printStackTrace ();} .RD<]BxJ  
} =c8}^3L~7  
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private void processErrorCode(int nErrorCode) _O9V"DM  
{ Rr) 5[  
System.err.println("Error Code : " + nErrorCode); B2`S0 H  
} }gp@0ri%5  
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WT *"V<Z  
//停止文件下载 ^-o{3Q(w  
public void siteStop() /:dLqyQ_V  
{ }nmlN  
bStop = true; 2YD\KXDo  
for(int i=0;i<nStartPos.length;i++) iFI74COam  
fileSplitterFetch.splitterStop(); #]#9Xq  
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} i'tMpS3  
}  W!Tx%  
//负责部分文件的抓取 m/HT3<F  
**FileSplitterFetch.java pR0[qsQM  
*/ ,Oo`*'a[o7  
package NetFox; QcegT/vO  
0K!3Ny9(  
4GYi'  
import java.io.*; lExQp2E  
import java.net.*; %6K7uvTq  
t)SZ2G1r  
|IxHtg3>6{  
public class FileSplitterFetch extends Thread { r]B8\5|<d  
2y[Q  
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String sURL; //File URL {Jr1K,  
long nStartPos; //File Snippet Start Position :X2_#qW#C  
long nEndPos; //File Snippet End Position -4Qub{Uym  
int nThreadID; //Thread's ID -V$|t<  
boolean bDownOver = false; //Downing is over jNZ.Fb  
boolean bStop = false; //Stop identical }F08o,`?  
FileAccessI fileAccessI = null; //File Access interface 4pmeu:26  
oO}g~<fYG  
[4KQcmJc#  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException u@a){A(P  
{ {v={q1  
this.sURL = sURL; _H]\  
this.nStartPos = nStart; @T1G#[C~t  
this.nEndPos = nEnd; ]m1fo'  
nThreadID = id; UpoSC  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 -@Ap;,=  
} Y,]Lk<Hm3  
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public void run() ?0qVyK_
1  
{ s 6Wp"V(  
while(nStartPos < nEndPos && !bStop) 0TN28:hcD  
{ so))J`ca)  
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try{ +LHU}'|  
URL url = new URL(sURL); *CN *G"  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); j?T'N:Qd  
httpConnection.setRequestProperty("User-Agent","NetFox"); iUkUo x  
String sProperty = "bytes="+nStartPos+"-"; `IHP_IfR  
httpConnection.setRequestProperty("RANGE",sProperty); )W\)37=.  
Utility.log(sProperty); I| TNo-!$  
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InputStream input = httpConnection.getInputStream(); UB~K/r`.|
 
//logResponseHead(httpConnection); e02Hf{eOfw  
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F
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byte[] b = new byte[1024]; 44CZl{
pt  
int nRead; [8ZDMe  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) jaS<*_~#R
 
{ ammi4k/  
nStartPos += fileAccessI.write(b,0,nRead); fe .=Z&  
//if(nThreadID == 1) c!w[)>v  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); '1u?-2  
} i?L=8+9f  
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/*C!]Z>.  
Utility.log("Thread " + nThreadID + " is over!"); \p!UY3'  
bDownOver = true; >N&{DJmD  
//nPos = fileAccessI.write (b,0,nRead); ^}  {r@F  
} *F$@!ByV  
catch(Exception e){e.printStackTrace ();} TE`5i~R*  
} Va!G4_OT  
} ^[hAj>7_8$  
=OufafZb  
hs6pp/h>  
//打印回应的头信息 M+"6VtZH  
public void logResponseHead(HttpURLConnection con) #p+iwW-  
{ HDm]njF%qQ  
for(int i=1;;i++) 2gWR2 H@  
{ wd:Yy  
String header=con.getHeaderFieldKey(i);  9qX$  
if(header!=null) YS3~sA  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); '}agi.z  
Utility.log(header+" : "+con.getHeaderField(header)); w4L()eP#?=  
else hcVu`Bn  
break; k?=1q[RQH  
} bH+NRNI]  
} VQIvu)I  
[;m@A\F  
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public void splitterStop() dv+Gv7&2/  
{ x,nl PU  
bStop = true; LhG\)>Y%  
} {S0-y  
.2I?^w&j+  
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} D5gj*/"  
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%9YY \a {  
/* "#)|WVa=BM  
**FileAccess.java /xX7:U b  
*//文件访问(定位，写) f@}>:x  
package NetFox; f y2vAwl  
import java.io.*; )\])?q61  
@x `X|>&  
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public class FileAccessI implements Serializable{ l]G iz&  
628iN%[-  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 NV5qF/<M  
RandomAccessFile oSavedFile; #cQ5-R-1  
long nPos; (iKJ~bJ  
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public FileAccessI() throws IOException |!FQQ(1b  
{ l/3=o}8q  
this("",0); ^cZ< .d2  
} b}TvQ+W]2  
yjT>bu]  
-1Tr!I:1  
public FileAccessI(String sName,long nPos) throws IOException AL":j6!OQ  
{ 20I`F>-*  
oSavedFile = new RandomAccessFile(sName,"rw"); 2]kGDeSr  
this.nPos = nPos; k"#gSCW$  
oSavedFile.seek(nPos); 4?Y7.:x  
} /<_!Gz.@uG  
WIU]>_$.  
!<TkX/O  
public synchronized int write(byte[] b,int nStart,int nLen) zgY VB
}  
{ nlpEkq  
int n = -1; VL)<u"d4  
try{ H!*ypJ  
oSavedFile.write(b,nStart,nLen); U/'l"N[  
n = nLen; G^B>C  
} RB4n>&Y  
catch(IOException e) k86TlQRh  
{ 7"eK<qJ  
e.printStackTrace (); 89>}`:xS^  
} af<h2r  
np2&W'C/i  
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return n; *AV%=  
} mr7Oi `dE  
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} NsI.mTc2  
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/* 3IRur,|'  
**SiteInfoBean.java OxDqLX  
*/ e6MBy\*n  
package NetFox; nA0%M1a  
.@fA_8  
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public class SiteInfoBean { ]I)ofXu]  
W,EIBgR(R5  
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private String sSiteURL; //Site's URL ?j8!3NCl}  
private String sFilePath; //Saved File's Path s,r|p@^  
private String sFileName; //Saved File's Name `U|7sLR  
private int nSplitter; //Count of Splited Downloading File Xfg3q.q  
t Cb34Wpf  
(rFiHv5  
public SiteInfoBean()  <O7!(  
{//nSplitter的缺省值为5 c2NB@T9'v  
//default value of nSplitter is 5 =/K)hI!u  
this("","","",5); WzstO}?P(  
} inh:b .,B  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) *EGzFXa  
{ g"748LY>=p  
sSiteURL= sURL; |\dv$`_T  
sFilePath = sPath; fV4rVy8  
sFileName = sName; z'l HL  
this.nSplitter = nSpiltter; ~;9n6U  
{
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-+{[.U<1jk  
} uGz)Vz&3  
4GP?t4][  
|dQz(z&6{5  
public String getSSiteURL() !-tw  
{ M~\dvJ$cH  
return sSiteURL; ATqblU>D  
} O|sk"YXF  
y5F+~z}{  
KANR=G  
public void setSSiteURL(String value) hlL$3.]  
{ 2$Xof  
sSiteURL = value; (m
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} oc)`hg2=  
1N(#4mE=  
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public String getSFilePath() l6#Y}<tq  
{ V\m"Hl>VIU  
return sFilePath; .O"a:^i  
} kf>3T@  
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=q0V%h{  
public void setSFilePath(String value) ( 0/M?YQF  
{ [3bPoAr\  
sFilePath = value; 7zCJ3p  
} 2`*w*  
~\(c;J*Ir  
[ne51F5_  
public String getSFileName() }0pp"
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{ /%g9g_rt#  
return sFileName; _|US`,kfc  
} 5H.~pc
2y  
hy~[7:/<I&  
%IBT
85{  
public void setSFileName(String value) R/x3+_.f  
{ !b_(|~7Lc  
sFileName = value; ["f6Ern  
} 27fLW&b2  
=V|jd'iwx  
c45s #6  
public int getNSplitter() r<fcZ)jt|  
{ P}~MO)*1  
return nSplitter; m6[}KkW  
} rmzzbLTu  
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public void setNSplitter(int nCount) C0[U}Y/r2  
{ s1Acl\l-uF  
nSplitter = nCount; HhQ0>  
} j~>{P=_}  
} ^Zz^h@+  
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2c]"*Pb  
/* Ez~5ax7x  
**Utility.java "7y,d%H  
*/ 2|^@=.4\  
package NetFox; :.ZWYze  
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public class Utility { &PE%tm  
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public Utility() 0#OyT'~V%  
{ <~
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} 'Z~ZSu  
U4=l`{5on  
//线程睡眠 f2x!cL|Kx?  
public static void sleep(int nSecond) '27$x&6>S  
{ xx!8cvD4?  
try{ SPE)db3  
Thread.sleep(nSecond); v^@)&,  
}
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catch(Exception e) ,5v'hG  
{ =xm7i#1  
e.printStackTrace (); I
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} q  
} '(@q"`n  
J-tq
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//日志 +o`%7r(R  
public static void log(String sMsg) {WV"]O8IV  
{ RJ@79L*#  
System.err.println(sMsg);
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} Mc.{I"c@  
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pFS@yHs  
public static void log(int sMsg) Uo >aQk  
{ (0.oE%B",1  
System.err.println(sMsg); [tkx84M8  
} f;^ +q-Q  
} _ +DL   
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>[aR8J/U  
/* ^g*Sy, A  
**TestMethod.java ={%'tv`  
*/ )iw-l~y;  
package NetFox;  B`e/ /  
Ck )W=  
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public class TestMethod { J[:#(c&c!1  
^(^P#EEG  
m@XX2l9:9  
public TestMethod() xR0*w7YE  
{ ///xx/weblogic60b2_win.exe _">F]ptI;  
try{ UDr1t n  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); v_5qE  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ru 6`Z+p  
SiteFileFetch fileFetch = new SiteFileFetch(bean); [<@T%yq  
fileFetch.start(); (G>su  
} Q,5PscE6&k  
catch(Exception e){e.printStackTrace ();} _C5i\Y
)  
\)/qCeiZ  
e#Ao]gc  
} 9<?w9D.1  
<&b,%O  
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public static void main(String[] args) ^slIR!L  
{ LSc^3=X  
new TestMethod(); 8_!qoW@B  
} ,nYa+
e  
} ?I^$35  
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