http断点续传简单实现（java)

/* CY1Z'  
**SiteFileFetch.java vt8By@]:  
*/ TxD#9]Q`  
package NetFox; ~a:  
import java.io.*; qna8|3
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import java.net.*; XZ7Lk)IR  
 )2.Si#  
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public class SiteFileFetch extends Thread { XwmL.Gg:]7  
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SiteInfoBean siteInfoBean = null; //文件信息Bean KPF1cJ2N  
long[] nStartPos; //开始位置 QV!up^Zso  
long[] nEndPos; //结束位置 Sc0w.5m6  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 r;{.%s7  
long nFileLength; //文件长度 C_Dn{  
boolean bFirst = true; //是否第一次取文件 U/U
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boolean bStop = false; //停止标志 t0S1QC+  
File tmpFile; //文件下载的临时信息 t_^4`dW`  
DataOutputStream output; //输出到文件的输出流  e
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） mt .sucT  
public SiteFileFetch(SiteInfoBean bean) throws IOException KoT\pY^7\  
{ f#;>g  
siteInfoBean = bean; @dKTx#gZ  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); J5
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tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); _)8s'MjA:&  
if(tmpFile.exists ()) ,bi^P>X  
{ 9w"*y#_  
bFirst = false; 4 KiY6
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read_nPos(); 6m93puY
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} V0@=^Bls  
else .A
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{ [JiH\+XLPs  
nStartPos = new long[bean.getNSplitter()]; CJ}%W#  
nEndPos = new long[bean.getNSplitter()]; 1zv'.uu.,  
} 4RO}<$Nx}  
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} 3fj4%P"  
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public void run() <~)P7~$d?p  
{ +7Gwg  
//获得文件长度 [n@] r2g)3  
//分割文件 %b$>qW\*&  
//实例FileSplitterFetch [txE .7p  
//启动FileSplitterFetch线程 )9g2D`a4  
//等待子线程返回 Lbgi7|&  
try{ y[;>#j$  
if(bFirst) 1EK*g;H  
{ ="+#W6bZT  
nFileLength = getFileSize(); Txu/{M,  
if(nFileLength == -1) 2/?|&[  
{ P.cyO3l  
System.err.println("File Length is not known!"); KlEpzJ98  
} Jy)/%p~  
else if(nFileLength == -2) 5pX6t  
{ _BufO7`.  
System.err.println("File is not access!"); ("KF'fp&M2  
} 1MFbQs^  
else [Xkx_B  
{ hN_]6,<\  
for(int i=0;i<nStartPos.length;i++) =;L|gtH"  
{ $xsd~L&  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); wYea\^co  
} c<~H(k'+c  
for(int i=0;i<nEndPos.length-1;i++) U{mYTN*:j$  
{ }MySaL>  
nEndPos = nStartPos[i+1]; "]*tLL:`  
} k$VlfQ'+  
nEndPos[nEndPos.length-1] = nFileLength; >P(.:_^p  
} [),ige  
} (3e2c  
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//启动子线程 WH\d| 1)  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; I
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for(int i=0;i<nStartPos.length;i++) ib m4fa  
{
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fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ~*7]r`6\@  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 'u658Tj  
nStartPos,nEndPos,i); y_,bu^+*  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); *8q.YuZ  
fileSplitterFetch.start(); 4-w{BZuS  
} DG/Pb)%Y  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), KvSG;  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); [ ~,AfY  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", (H]AR8%W  
nEndPos = " + nFileLength); 1YA% -~  
// fileSplitterFetch[nPos.length-1].start();
[aS*%Heu  
& kIFcd@  
'qi}|I  
//等待子线程结束 :gT4K-Oj  
//int count = 0; E^PB)D(.  
//是否结束while循环 J,G lIv.A  
boolean breakWhile = false; =41xkAMnk  
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|{;G2G1[  
while(!bStop)
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{ ivPg9J1S  
write_nPos(); $( )>g>%  
Utility.sleep(500); Bx!-"e  
breakWhile = true; ;4a{$Lw~^9  
!wNO8;(  
VL^EHb7  
for(int i=0;i<nStartPos.length;i++) f::Dx1VcX  
{ Mtv?
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if(!fileSplitterFetch.bDownOver)  OSJ$d  
{ \jA~9  
breakWhile = false; >7r!~+B"9'  
break; #g=XUZ/"  
} Q&&@v4L  
} xPgBV~  
if(breakWhile) E9}C #  
break; DJir{ \F  
F?cK-.  
23?rEhKe  
//count++; F/Pep?'  
//if(count>4) Wm|lSisY  
// siteStop(); h1{3njdr  
} H:G1BZjq  
iCyfOh  
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System.err.println("文件下载结束！"); <ih[TtZ  
} b[7]F  
catch(Exception e){e.printStackTrace ();} %bfZn9_m  
} 2-b6gc7  
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XUw/2"D'?  
//获得文件长度 wAd
9  
public long getFileSize() fzA9'i`  
{ "\=U)CJ  
int nFileLength = -1; =2 kG%9  
try{ rbpSg7}Q  
URL url = new URL(siteInfoBean.getSSiteURL()); _2nx^E(pd  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); $A`VYJtt#  
httpConnection.setRequestProperty("User-Agent","NetFox"); %IRi1EmN8  
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int responseCode=httpConnection.getResponseCode(); ;GhNKPY
 
if(responseCode>=400) :@)>r9N  
{ ? qA]w9x  
processErrorCode(responseCode); =ruao'A  
return -2; //-2 represent access is error }T$p)"  
} :eg4z )  
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9S-9.mvop  
String sHeader; B]$GSEB  
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for(int i=1;;i++) `KQvJjA6  
{ P2*<GjV`S/  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); F/A|(AH'  
//Utility.log(in.readLine()); H4JTGt1"  
sHeader=httpConnection.getHeaderFieldKey(i); 9M9?%N:ra  
if(sHeader!=null) T5:G$-q
L(  
{ F3N6{ysK#  
if(sHeader.equals("Content-Length")) Ki~1qu:  
{ @<Yy{~L|  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); pBPl6%C.X-  
break; n}77##+R&C  
} _7)n(1h[3b  
} ~WN:DXn  
else D)'bH5  
break; L~>i,  
} ;Z
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} 0C*7K?/  
catch(IOException e){e.printStackTrace ();} -o.:P>/  
catch(Exception e){e.printStackTrace ();} zA"`!}*  
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Utility.log(nFileLength); 9<)NvU^-r  
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return nFileLength; s|B3~Q]  
} CsifKHI  
PAOJ\U  
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//保存下载信息（文件指针位置） o7LuKRl   
private void write_nPos() 5
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:  
{ f0aKlhEC  
try{ ]}(H0?OQR  
output = new DataOutputStream(new FileOutputStream(tmpFile)); l?^4!&Nm  
output.writeInt(nStartPos.length); U!Z,xx[]  
for(int i=0;i<nStartPos.length;i++) SG4%}wn%  
{ %-e 82J1  
// output.writeLong(nPos); g2/8~cn8z  
output.writeLong(fileSplitterFetch.nStartPos); xpx\=iAe  
output.writeLong(fileSplitterFetch.nEndPos); :Qf '2.h)  
} :TC@tM~Oy  
output.close(); NS6:yX,/  
} Q'mM3pq4r  
catch(IOException e){e.printStackTrace ();} !o[7wKrXb  
catch(Exception e){e.printStackTrace ();} Oh\<VvZuN  
} 0tB0@Wj  
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_M5|Y@XN-  
//读取保存的下载信息（文件指针位置） HuKc9U'7A  
private void read_nPos() f &wb  
{  H =^`!  
try{ usL* x
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DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); \qK&q  
int nCount = input.readInt(); =+MPFhvg!  
nStartPos = new long[nCount]; g]yBA7/S"  
nEndPos = new long[nCount]; %O;bAC_M  
for(int i=0;i<nStartPos.length;i++) bl(RyAgA  
{ JNUt$h  
nStartPos = input.readLong(); B=A [ymm  
nEndPos = input.readLong(); pDCeQ6?  
} e?ly
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input.close(); w+E,INdi  
} pWsDzb6?%  
catch(IOException e){e.printStackTrace ();} QM#4uI55B  
catch(Exception e){e.printStackTrace ();} )Z?Ym.0/  
} )fSOi||C  
:|8M`18lZ  
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private void processErrorCode(int nErrorCode) tX %5BTv  
{ '>ssqBnI  
System.err.println("Error Code : " + nErrorCode); Z//+Gw<'  
} vf%&4\ib  
Q_X.rUL0w  
!XCm>]R  
//停止文件下载 "z=SO1  
public void siteStop() l +OFw)8od  
{ thM4vq  
bStop = true; Uu(SR/R}  
for(int i=0;i<nStartPos.length;i++) os={PQRD  
fileSplitterFetch.splitterStop(); :G2k5xD/E  
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/M4{Wc  
} ,TN 2  
} 72y0/FJ  
//负责部分文件的抓取 Z}l3l`h!  
**FileSplitterFetch.java pDIVZC  
*/ ^_u kLzP9  
package NetFox; DSk/q-'u  
khrb-IY@  
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import java.io.*; DhT>']Z  
import java.net.*; OJ$]V,Z00x  
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public class FileSplitterFetch extends Thread { ^1aAjYFn  
7-T{a<g  
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String sURL; //File URL xz{IH,?IG  
long nStartPos; //File Snippet Start Position %\r!7@Q  
long nEndPos; //File Snippet End Position oK%K}{`  
int nThreadID; //Thread's ID ?Ovqp-sw  
boolean bDownOver = false; //Downing is over ]U7KLUY>:  
boolean bStop = false; //Stop identical dwd:6.J(  
FileAccessI fileAccessI = null; //File Access interface u(t#Ze~Y1  
:`2=@.  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException [[Y
0  
{ ['*8IWg  
this.sURL = sURL; OdY=z!Fls  
this.nStartPos = nStart; DHT&,=  
this.nEndPos = nEnd; k`p74MWu  
nThreadID = id; {TRsd  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 _#}n~}d  
} 01. &>Duw  
SdwS= (e6  
]B]*/  
public void run() Z)xaJGbw  
{ t2iv(swTe  
while(nStartPos < nEndPos && !bStop) xvSuPP4 m  
{ 3y~r72J  
S
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try{ [kgdv6E  
URL url = new URL(sURL); \y{Tn@7  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); rf%7b8[v  
httpConnection.setRequestProperty("User-Agent","NetFox"); p/ >`[I  
String sProperty = "bytes="+nStartPos+"-"; [e4]"v`N  
httpConnection.setRequestProperty("RANGE",sProperty); 2kUxD8BcN  
Utility.log(sProperty); y tf b$;|  
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InputStream input = httpConnection.getInputStream(); 7 +@qB]Bi<  
//logResponseHead(httpConnection); #vqo -y7@  
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byte[] b = new byte[1024]; VCcr3Dx()F  
int nRead; e~T@~(fft  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) K!mOr  
{ %D`,k*X  
nStartPos += fileAccessI.write(b,0,nRead); 0G2g4DSKD  
//if(nThreadID == 1) 5Fm=/o1  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Wi}FY }f  
} pBC<u  
5Y3i|cj  
;!T{%-tP  
Utility.log("Thread " + nThreadID + " is over!"); cubk]~VD  
bDownOver = true; S-nlr@w8  
//nPos = fileAccessI.write (b,0,nRead); Z_1*YRBY;  
} ^R$'eG 4L?  
catch(Exception e){e.printStackTrace ();} -n? g~(/
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} p=QYc)3F  
} jUqy8q&  
+"g~"<  
4E:bp   
//打印回应的头信息 ksjUr1o  
public void logResponseHead(HttpURLConnection con) 9(!]NNf!  
{ xDO7A5  
for(int i=1;;i++) mty1p'^KQ  
{ ,A5)<}  
String header=con.getHeaderFieldKey(i); )OsLrq/  
if(header!=null) (HN4g;{  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ,`8Y8  
Utility.log(header+" : "+con.getHeaderField(header)); 
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else "MiD8wX-  
break; h.whjiCFa  
} )J3kxmlzQ  
} HpexH{.u)  
#rYENR[  
H%z@h~s>  
public void splitterStop() em]xtya  
{ T_OF7?  
bStop = true; K.SeK3(  
} 5GAy "Xd  
1:= `Y@.S  
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} =<<3
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/* H*W):j}8  
**FileAccess.java =J|sbY"]  
*//文件访问(定位，写) y?N Nz0  
package NetFox; +EASAq  
import java.io.*; Eo{EKI1  
G"S5ki`o  
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public class FileAccessI implements Serializable{ F1A1@{8bN  
9[|4[3K  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 BGjb`U#%3  
RandomAccessFile oSavedFile; j.QHkI1.  
long nPos; +*t|yKO>[  
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public FileAccessI() throws IOException K~>jApZ%  
{ U4_"aT>My  
this("",0); b
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} 1-$P0  
vbn>mg5  
cjg=nTsBA  
public FileAccessI(String sName,long nPos) throws IOException d1NE%hg3  
{ YMAQ+A!  
oSavedFile = new RandomAccessFile(sName,"rw"); 8t9aHla  
this.nPos = nPos; O:u%7V/  
oSavedFile.seek(nPos); YkbO&~.  
} 6`"ZsO  
U,3d) ]Zy&  
Cj$H[K}>  
public synchronized int write(byte[] b,int nStart,int nLen) FT_k
^CC  
{ R`C.ha  
int n = -1; l%bq2,-%  
try{ Y\u_+CG*  
oSavedFile.write(b,nStart,nLen); 0Uaem  
n = nLen; n1)'cS5}  
} &enlAV'#)O  
catch(IOException e) oUS,+e  
{ AJWLEc4XK  
e.printStackTrace (); QX/]gX  
} B'/Icg.T  
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={xqNRVd  
return n; 83xd@-czgh  
} *cy.*@d  
>%i9oI<)  
,^!Zm^4,  
} GFY-IC+fc  
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K*[0dza$  
/* 9H8=eJd  
**SiteInfoBean.java \y,;Cfl<  
*/ T/5nu?v  
package NetFox; m^c%]5$  
K5+!(5V~  
l^BEFk;  
public class SiteInfoBean { 0c-QIr}m  
_jk|}IB;X  
F94V5_[  
private String sSiteURL; //Site's URL o8m
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private String sFilePath; //Saved File's Path pV_}Or_  
private String sFileName; //Saved File's Name tc5M$b3^2  
private int nSplitter; //Count of Splited Downloading File F1/6&u9I  
frk7^5  
9c:5t'Qt5.  
public SiteInfoBean() 2kC^7ZAwu  
{//nSplitter的缺省值为5 Za34/ro/T  
//default value of nSplitter is 5 # e$\~cPd  
this("","","",5); 0U9+  
} nO-d"S*  
M2a}x+5'  
x ru(Le}E  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) M3)v-"  
{ _dz+2au  
sSiteURL= sURL; fHW-Je7mG  
sFilePath = sPath; W&WB@)ie  
sFileName = sName;  9F/|`  
this.nSplitter = nSpiltter; J: L-15  
R A*(|n>  
#^"hqNwA  
} \-DM-NrZ1U  
7^`RP e^a+  
aS3P(s L  
public String getSSiteURL() ks)fQFSbu  
{ YmdsI+DbIu  
return sSiteURL; oM/B.U2a  
} (*LTqC  
?S+/QyjcfJ  
W,0KBkkp  
public void setSSiteURL(String value) sxf}Mmsk  
{ `#-p,NElV  
sSiteURL = value; 4da^d9ZOy  
} E!r4AjaC  
O@G<B8U,K  
tsCz+MP  
public String getSFilePath() s0x@ u  
{ L5hQdT/b$  
return sFilePath; {"qW~S90YO  
} ;igEIGR  
\ x>NB  
wWp?HDl"M  
public void setSFilePath(String value) o{s4.LKK  
{ NB~*sP-l&  
sFilePath = value; &lOXi?&"  
} 1q;I7_{ 2
 
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public String getSFileName() J tn&o"C  
{ :Kt{t46)  
return sFileName; arpJiG~JR  
} &q"uy:Rd  
rzc 3k~@  
'6Rs0__  
public void setSFileName(String value) C5W-B8>  
{ lcuH]z  
sFileName = value; F~11 _  
} RMs1{64:  
06j)P6Iju  
d@`-!"  
public int getNSplitter() EHE6-^F  
{ AmrJ_YP/t~  
return nSplitter; l.Lc]ZpB  
} AH ?MJKY@Z  
b W`)CWd  
)2*
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public void setNSplitter(int nCount)  t}*
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{ +L<w."WG  
nSplitter = nCount; pB{ f-M:D  
} +LU).  
} Xl '\krz  
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^{:[^$f:l  
/* ,m_&eF  
**Utility.java hKH Q!`&v  
*/ [s& y_[S  
package NetFox; 2oNPR+ -  
itvy[b-*  
:O_<K&  
public class Utility { e^K=8IW  
,YuWz$aF{  
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public Utility() K<fq=:I3  
{ okW)s*7  
G5
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-$Z-hxs^  
} ~(L<uFU V  
:8/M6-EK  
//线程睡眠 .LVOaxT  
public static void sleep(int nSecond) . KSr@Gz  
{ `5aypJf1  
try{ S7~l%G>]b  
Thread.sleep(nSecond); 9\;/-0P  
} _}%#Yz  
catch(Exception e) Zm'::+tl  
{ X+G*Q}5  
e.printStackTrace (); BsG[#4KM:  
} =u1w\>(2Y  
} 5v03<m0`y  
0GLB3I >  
//日志 H@bm
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public static void log(String sMsg) [/`Hz]R  
{ 7m)ykq:?  
System.err.println(sMsg); \<
+47+  
} 2ZFKjj  
Z.#glmw^=R  
SNV+.xN  
public static void log(int sMsg) BY2txLLB  
{ :JG}%  
System.err.println(sMsg); _|#|mb4Fe  
} \.-y LS.  
} FbT&w4Um=  
].+G-<.:  
-2~yc2:>A  
/* ]cY'6'}Hz  
**TestMethod.java wAwH8xLU  
*/ i3!$M/_]  
package NetFox; ?At-   
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L&k$4,Z9  
public class TestMethod { %Q4w9d  
w%u[~T7OI  
PqeQe5  
public TestMethod() 2PW3S{Dt  
{ ///xx/weblogic60b2_win.exe .aRxqFi_  
try{ 1;9E*=  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); uy%PTi+A  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); -5B([jHgR  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 43]&SXprH  
fileFetch.start(); oU6g5  
} ~Q\uP(!D  
catch(Exception e){e.printStackTrace ();} { J%$.D(/  
DcM+K@1E4^  
`SbX`a0p2  
} T$B4DQ  
eEFT(e5.>3  
eWs^[^c.<  
public static void main(String[] args) jWCC`0 T  
{ <qiap2  
new TestMethod(); #FM 'S|  
} E8 )*HOT_T  
} 30-wTcG  
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