http断点续传简单实现（java)

/* O;f^'N  
**SiteFileFetch.java )VJAs|  
*/ ?+GbPG~  
package NetFox; +-'qI_xo  
import java.io.*; E xKH%I  
import java.net.*; rfYu8-  
c }ivYH?`w  
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public class SiteFileFetch extends Thread { EG&^;uU  
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SiteInfoBean siteInfoBean = null; //文件信息Bean B+
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long[] nStartPos; //开始位置 p\:_E+lsU  
long[] nEndPos; //结束位置 "*l
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FileSplitterFetch[] fileSplitterFetch; //子线程对象 y4
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long nFileLength; //文件长度 *)ed(+b  
boolean bFirst = true; //是否第一次取文件 J:f>/  
boolean bStop = false; //停止标志 l}335;(  
File tmpFile; //文件下载的临时信息 <,Sy:>:"  
DataOutputStream output; //输出到文件的输出流 0ang~_  
vQ+}rHf`[  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） T =3te|fv  
public SiteFileFetch(SiteInfoBean bean) throws IOException /`\-.S9  
{ Jl Q%+$  
siteInfoBean = bean; yr&oJYM  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); YC&iH>jO3  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); _|DP  
if(tmpFile.exists ()) %%c0UaV  
{ vIU+ZdBw  
bFirst = false; r{)d?Ho=  
read_nPos(); p$f#W  
} (J.(Fl>^  
else ^K@r!)We  
{ 6\ux;lksn*  
nStartPos = new long[bean.getNSplitter()]; vc6UA%/f  
nEndPos = new long[bean.getNSplitter()]; tt[P{mMQ  
} [2
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} ZyCAl9{p  
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public void run() au"HIyi?k  
{ P:lvZ   
//获得文件长度 kSU5  }  
//分割文件 KrMIJA4>  
//实例FileSplitterFetch H4l:L(!D  
//启动FileSplitterFetch线程 bw%1*;n)  
//等待子线程返回 )FWF T:P~  
try{ dadOjl)S)
 
if(bFirst) =e$ #m;  
{ zIF &ZYP  
nFileLength = getFileSize(); lUUq|Qr  
if(nFileLength == -1) `Kym{og  
{ (n" )  
System.err.println("File Length is not known!"); P7egT,Z  
}
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else if(nFileLength == -2) :m#vvH  
{ MFW?m,It)  
System.err.println("File is not access!"); hp-<8Mf  
} ,z1# |Y  
else enG6T  
{ YL){o$-N"J  
for(int i=0;i<nStartPos.length;i++) U%oI*  
{ N#7]xL  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 3 %DA{  
} X&
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for(int i=0;i<nEndPos.length-1;i++) 4bAgbx-^  
{ ,;/4E
 
nEndPos = nStartPos[i+1]; NnHwk)'  
} V]q{N-Iq  
nEndPos[nEndPos.length-1] = nFileLength; u:HKmP;  
} )V@qH]  
} }S#.Pw%  
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//启动子线程 ]XPGlM  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; d[~c-G6  
for(int i=0;i<nStartPos.length;i++) 7[D0n7B@  
{ C{!Czz.N  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), N"r ;d+LTL  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), _'I9rGlx3  
nStartPos,nEndPos,i); '')G6-c/  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 7y[B[$P  
fileSplitterFetch.start(); M<ad>M  
} l$zNsf.  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ,1~Zqprn  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); >F+:ej  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ]G1j\wnF  
nEndPos = " + nFileLength); HhqqJEp0  
// fileSplitterFetch[nPos.length-1].start(); <U~P-c tN  
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$hKgTf?  
//等待子线程结束 \&TTe8  
//int count = 0; E32z(:7M  
//是否结束while循环 `/HygC6  
boolean breakWhile = false; 3_h%g$04s  
PA,j;{,(b  
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while(!bStop) ?5(L.XFm  
{ 9tx
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write_nPos(); Ys<wWfW  
Utility.sleep(500); QlXy9-oJ"  
breakWhile = true; Rp@u.
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for(int i=0;i<nStartPos.length;i++) R(zsn;  
{ wz, \zh  
if(!fileSplitterFetch.bDownOver) wR;l"*
j  
{ EXBfzK)a  
breakWhile = false; ~(Tz <  
break; ~f@<]  
} BMdr.0  
} AoR`/tr,  
if(breakWhile) &a|oJ'clz  
break; TM"-X\e~{  
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i
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//count++; [=9R5.)c  
//if(count>4) .Z^g 7 *s  
// siteStop(); B}MJ?uvA  
} %]R#}amW  
^#=L?e  
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System.err.println("文件下载结束！"); 8odVdivh  
} xO.7cSqgw  
catch(Exception e){e.printStackTrace ();} $(NfHIX  
} ~Fx[YPO,  
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kl={L{r  
//获得文件长度 - a=yid  
public long getFileSize() %bimcRX#W  
{ q@\_q!  
int nFileLength = -1; sbs"26IE  
try{ .U1dcL6  
URL url = new URL(siteInfoBean.getSSiteURL()); Y{O&-5H^|  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); p;5WLAF  
httpConnection.setRequestProperty("User-Agent","NetFox"); b9YpUm7#  
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6 %=BYDF  
int responseCode=httpConnection.getResponseCode(); {10ms_s  
if(responseCode>=400) tS9m8(Hr%Q  
{ [qXpi'q[  
processErrorCode(responseCode); 7d<v\=J
}  
return -2; //-2 represent access is error -m@s 9k  
} 1]<!Xuk^f  
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String sHeader; 0GR9opZtA  
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for(int i=1;;i++) p']AXJ`Z  
{ ]S:@=9JB'  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); [_0g^(`  
//Utility.log(in.readLine()); jG2w(h/"  
sHeader=httpConnection.getHeaderFieldKey(i); [D,:=p`  
if(sHeader!=null) |u+&xX7  
{ D#$gdjZ  
if(sHeader.equals("Content-Length")) U;nC)'~YW9  
{ UQ8x#(`ak  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); NV gLq@F  
break; ~mp$P+M(%p  
} t,+S~Cj|  
} iWCV(!  
else s +GF-kJ*  
break; IN"vi|1  
} N:<O  
} Y]lqtre*Y  
catch(IOException e){e.printStackTrace ();} $"i690  
catch(Exception e){e.printStackTrace ();} vqs~a7E-P  
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Utility.log(nFileLength); 6Te}"t>  
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)  
return nFileLength; [s/@z*,M1  
} cDx
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n,F00YR  
% n{W

  
//保存下载信息（文件指针位置） ${+.1"/[  
private void write_nPos() !lF^~x  
{ :qbG%_PJ  
try{ 'l:2R,cP  
output = new DataOutputStream(new FileOutputStream(tmpFile)); J4vKfxEg  
output.writeInt(nStartPos.length); A1q^E(}O  
for(int i=0;i<nStartPos.length;i++) P&GZe/6Y  
{ p4t)Z#0  
// output.writeLong(nPos); sfV.X:ev  
output.writeLong(fileSplitterFetch.nStartPos); x.yL'J\)  
output.writeLong(fileSplitterFetch.nEndPos); *p3P\ H^5  
} SSXS  
output.close(); 64lEB>VNm  
} eTc`FXw`  
catch(IOException e){e.printStackTrace ();} ETOc4h
MO  
catch(Exception e){e.printStackTrace ();} hkJZqUA  
} jE#8&P~  
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wb[(_@eZ  
//读取保存的下载信息（文件指针位置） X W)A~wPBs  
private void read_nPos() =5`@:!t7  
{ #H`y1zm  
try{ 2FzS_\":I  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); RV`j>1  
int nCount = input.readInt(); RuZ;hnE&  
nStartPos = new long[nCount]; CiuN26>  
nEndPos = new long[nCount]; }#8uXA  
for(int i=0;i<nStartPos.length;i++) m'tk#C  
{ 50&F#v%YB  
nStartPos = input.readLong(); 9ojhI=:  
nEndPos = input.readLong(); gcxk'd  
} sQZ8<DpB  
input.close(); f>dkT'4  
}
,7P^]V1  
catch(IOException e){e.printStackTrace ();} }^[@m#  
catch(Exception e){e.printStackTrace ();} 1VFqT'  
} pCc7T-"og  
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!j9i=YDb  
private void processErrorCode(int nErrorCode) .Qt3!ek  
{ gN(hv.nQ  
System.err.println("Error Code : " + nErrorCode); c0&'rxi(B  
} v|@n8ED|@K  
'I]"=O,  
]5fM?:<l  
//停止文件下载 ts<dUO  
public void siteStop() "6yiQ\`J  
{ Td*Oljj._U  
bStop = true; bFezTl{M  
for(int i=0;i<nStartPos.length;i++) 5V~p@vCx  
fileSplitterFetch.splitterStop(); 6# ";W2  
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>UY_:cW4%m  
} 9M]"%E!s  
} |"qB2.[  
//负责部分文件的抓取 ~C'nBV  
**FileSplitterFetch.java FH8mK)  
*/ `uVW<z{l  
package NetFox; ;6nZ  
cl{W]4*$  
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import java.io.*; -5 /v`  
import java.net.*; ~[TKVjyO  
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public class FileSplitterFetch extends Thread { b',bi.FH  
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String sURL; //File URL Tki/d\!+  
long nStartPos; //File Snippet Start Position PbUcbb17  
long nEndPos; //File Snippet End Position ,'CWt]OS'  
int nThreadID; //Thread's ID 4V|z)=)A  
boolean bDownOver = false; //Downing is over yM:~{;HLF  
boolean bStop = false; //Stop identical h#>L:Wf5E  
FileAccessI fileAccessI = null; //File Access interface i i
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F.pHL)37  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 9C}aX}`  
{ 4c[)}8\  
this.sURL = sURL; 6BU0hV  
this.nStartPos = nStart; ^>8]3@ Nh  
this.nEndPos = nEnd; &17,]#3  
nThreadID = id; ](>7h_2B  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Xm:=jQn  
} iWM7,=1+  
~}-p5q2  
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public void run() c48J!,jCd'  
{ %;(|KrUN  
while(nStartPos < nEndPos && !bStop) OI_/7@L  
{ U
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try{ Of7) A  
URL url = new URL(sURL); 7Sz'vyiz  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); >'-w%H/  
httpConnection.setRequestProperty("User-Agent","NetFox"); 6~h1iY_~  
String sProperty = "bytes="+nStartPos+"-"; M1]6lg[si  
httpConnection.setRequestProperty("RANGE",sProperty); YD46Z~$  
Utility.log(sProperty); "Dl9<EZ  
?ey&Un"  
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InputStream input = httpConnection.getInputStream(); b^,Mw8KsO  
//logResponseHead(httpConnection); x)VIA]  
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byte[] b = new byte[1024]; 8#]7`o  
int nRead; i\Pr3 7 "  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ^UvK~5tBV  
{
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nStartPos += fileAccessI.write(b,0,nRead); T]#,R|)d  
//if(nThreadID == 1) @SC-vc  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); O/Mz?$8J  
} J4[x,(iq(  
))IgB).3M  
r($_>TS&"  
Utility.log("Thread " + nThreadID + " is over!"); foz5D9sQ  
bDownOver = true; kyxSIQ^  
//nPos = fileAccessI.write (b,0,nRead); ?$J7%I@  
} |c oEBFG  
catch(Exception e){e.printStackTrace ();} F7Dc!JNa  
} Jn<e"  
} LPapD@Z  
t
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//打印回应的头信息 we\b]  
public void logResponseHead(HttpURLConnection con) 2JA&{c
h  
{ %<w
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for(int i=1;;i++) u3M`'YCb  
{ ^\vfos  
String header=con.getHeaderFieldKey(i); N8kb-2  
if(header!=null) )_9e@~,  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); v$)@AE  
Utility.log(header+" : "+con.getHeaderField(header)); /=muj9|+s  
else D]pK=247  
break; s-GleX<  
} b#p~F}qT  
} S:p.W=TAB  
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!$p2z_n$@.  
public void splitterStop() ti{H(;;@  
{ ?)?IZ Qj  
bStop = true; V#zhGAMy.  
} ]{AOh2Z.hv  
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} vn0cKz@  
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/* mEB2RLCM  
**FileAccess.java vJTfo#C|  
*//文件访问(定位，写) c#{Ywh  
package NetFox; ~mXZfG/D  
import java.io.*; ^A *]&%(h  
(:.Q\!aZ1  
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public class FileAccessI implements Serializable{ P~Te+ -jX}  
*xX(!t'  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 [GR]!\!%~  
RandomAccessFile oSavedFile; ]cF1c90%  
long nPos; e8d5(e  
9C557$nS^  
9n>$}UI\  
public FileAccessI() throws IOException #1QX!dK+  
{ 1u"R=D9p,=  
this("",0); %rpR-}j  
} , @%C8Z  
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public FileAccessI(String sName,long nPos) throws IOException ?ID* /u|X  
{ N?qIpv/a.  
oSavedFile = new RandomAccessFile(sName,"rw"); hmK8jl<6  
this.nPos = nPos; j+_S$T8w  
oSavedFile.seek(nPos); \6`v.B&v  
} 2 ) TG  
$ZQlIJZ  
6QN1+MwB  
public synchronized int write(byte[] b,int nStart,int nLen) 8- dRdQu]  
{ YPF&U4CN  
int n = -1; Bii6Z@kS  
try{ sg3h i"Im  
oSavedFile.write(b,nStart,nLen); N<KKY"?I'  
n = nLen; {PN:bb  
} \We"
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catch(IOException e) 98ca[.ui  
{ 6#E]zmXO2  
e.printStackTrace (); 0s860Kn  
} 0zeUP{MQ  
!(kX~S  
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return n; wl7 MfyU  
} 2Ryp@c&r^  
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} q{a#HnZo"  
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yJnPD/i  
/* ]UK`?J=t2g  
**SiteInfoBean.java :&Qb>PH[  
*/ 'n~fR]
h}  
package NetFox; sS C?io  
60`+9(^  
fph-v-cl  
public class SiteInfoBean { e Wc_N  
y7CWBTH0>  
5B}3GBA  
private String sSiteURL; //Site's URL (FM4 ^#6  
private String sFilePath; //Saved File's Path Hab!qWK`  
private String sFileName; //Saved File's Name OZ
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private int nSplitter; //Count of Splited Downloading File 66oK3%[  
zLh Fbyn(  
{J{1`@  
public SiteInfoBean() ;!'qtw"CB  
{//nSplitter的缺省值为5 m'd^?Qc
 
//default value of nSplitter is 5 ;xL67e%?  
this("","","",5); h]qT1(I  
} GA.BI"l  
SV&kWbS  
!d\t:0;  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ,,S9$@R  
{ K6E}";;  
sSiteURL= sURL; !]yQ1@)*'  
sFilePath = sPath; "cwR^DoD&  
sFileName = sName; f:xUPH?+  
this.nSplitter = nSpiltter; [1NaH  
i#k-)N _$  
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} _HwpPRVP/  
*%3oyWwCd  
,NDh@VYe  
public String getSSiteURL() :#WEx_]  
{ >b'w'"  
return sSiteURL; qB+n6y%  
} &(g|="T  
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G=1m]>I8  
public void setSSiteURL(String value) -)X{n?i  
{ w5,6$#  
sSiteURL = value; NW)M?f+6  
} rw
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}f0u5:;Zth  
JfkTw~'R  
public String getSFilePath() q'.;W@m  
{ (]OFS;%  
return sFilePath; f7Zf}1|  
} "MTWjW*6  
Lj iI+NJ  
zHV|-R  
public void setSFilePath(String value) Hr6wgYPi  
{ H"O$&  
sFilePath = value; '|&,E#`  
} 8hZwQ[hr  
q8/ihA6:  
xo(k?+P>.  
public String getSFileName() l2(.>-#  
{ dN<5JQql  
return sFileName; wk@yTTnb  
} +5-]iKh  
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8
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public void setSFileName(String value) vb %T7  
{ ;,dkJ7M  
sFileName = value; iOll WkF  
} [%jxf\9jJ_  
Q&gPa]z]}  
@HvScg*Y  
public int getNSplitter() d5:tSO  
{ K@6`-|I  
return nSplitter; dnwdFsf  
} O4E(R?wd  
l~['[Ub0)
 
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public void setNSplitter(int nCount) [^M|lf   
{ x<@kjfm5  
nSplitter = nCount; HVGr-/  
} v J-LPTB  
} g?V&mu  
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XCm\z9F  
/* P_}/#N{C  
**Utility.java 7b46t2W<  
*/ y:,9I`aW  
package NetFox; 8?1o<8hV  
Ft) lp>3gv  
5z~\5x  
public class Utility { \yG`Sfu2  
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public Utility() ]^ #`j  
{ zP&q7 t;>  
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} H_Os4}  
Yx),6C3  
//线程睡眠 ?q!FG(  
public static void sleep(int nSecond) ~.6|dw\p!  
{ uY;R8CiD  
try{ Fu%X  
Thread.sleep(nSecond); :+:6_x  
} On&L#pf  
catch(Exception e) -\Z `z}D  
{ /EU; ?O  
e.printStackTrace (); .=XD)>$  
} 7)J6/('  
} {a@>6)  
#Qd'+M  
//日志 k" YHsn  
public static void log(String sMsg) !| xZ6KV  
{ 4LsHs
 
System.err.println(sMsg); KDD@%E  
} @rwU 1T33  
xGRT"U(  
VNj@5s  
public static void log(int sMsg) ]'k[u  
{ ?'sXgo.}  
System.err.println(sMsg); ru{f]|  
} mM5|K@0|  
} IqUp4}  
Z>2]Xx% \  
HabzCH  
/* @Tr&`Hi  
**TestMethod.java %hINpZMr  
*/ #)]c0]p  
package NetFox; SY1GR n  
0^#DNq*NQ  
p7C!G1+z  
public class TestMethod { CCqT tp  
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[bjN f2  
public TestMethod() xo  Gb  
{ ///xx/weblogic60b2_win.exe yN\e{;z`  
try{ :wipE]~4t  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); XdsJwn F  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ooE{V*Ie  
SiteFileFetch fileFetch = new SiteFileFetch(bean); O k7zpq  
fileFetch.start(); 2
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} (A{NF(   
catch(Exception e){e.printStackTrace ();} r5 yO5W  
Oq+E6"<y;?  
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} z(H?VfJo  
q4ipumy*  
2a`J%A  
public static void main(String[] args) l>&sIX  
{ .Xd0 Q=1h  
new TestMethod(); 8!zbF<W9  
} -(IC~   
} y ~AmG~  
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