http断点续传简单实现（java)

/* iSd?N}2,I  
**SiteFileFetch.java 9s $PrF  
*/ *)%dXVf  
package NetFox; i_Ar<9a~  
import java.io.*; ?M"HX
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import java.net.*; IQ{?_'  
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3}4#I_<$F@  
public class SiteFileFetch extends Thread { @&:VKpu\  
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SiteInfoBean siteInfoBean = null; //文件信息Bean )k%M.{&bji  
long[] nStartPos; //开始位置 u9}!Gq  
long[] nEndPos; //结束位置 \dNhzd#  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 "t+r+ipf])  
long nFileLength; //文件长度 N9*UMVU  
boolean bFirst = true; //是否第一次取文件 zlMlMyG4  
boolean bStop = false; //停止标志 cs5ix"1A  
File tmpFile; //文件下载的临时信息 8nu> gA  
DataOutputStream output; //输出到文件的输出流 @W)/\AZ3  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） "yri[X  
public SiteFileFetch(SiteInfoBean bean) throws IOException 2fBYT4*P;  
{ 9Z9l:}bO  
siteInfoBean = bean; .\4l'THn,0  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); K{FhT9R'  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Z!)f*  
if(tmpFile.exists ())
rIPl6,w~  
{ `r.N  
bFirst = false; ?d,M.o{0]  
read_nPos(); 5ZUy:  
} 65"uD7;  
else J" wKRy  
{ {e6KJ@H6  
nStartPos = new long[bean.getNSplitter()]; %#4 +!  
nEndPos = new long[bean.getNSplitter()]; 0%;MVMH  
} GWh|FEqUbf  
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} ~bFdJj 1*  
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public void run() r4S=I  
{ k) 3s
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//获得文件长度 \d$Rd")w  
//分割文件 /sH0x,V  
//实例FileSplitterFetch yjR)Z9t  
//启动FileSplitterFetch线程 |P~q/Wff  
//等待子线程返回 kpWzMd &RK  
try{ L B<UC?e  
if(bFirst) wJ(8}eI  
{ "_oLe;?$c  
nFileLength = getFileSize(); .SBc5KX  
if(nFileLength == -1) jRwa0Px(  
{ QP<FCmt8  
System.err.println("File Length is not known!"); s!i:0}U  
} 2i"HqAB  
else if(nFileLength == -2) @oA0{&G{  
{ [^Q&suy  
System.err.println("File is not access!"); $&Ac5Zo%}  
}
`M6YblnJZ  
else 1zR/HT  
{ ac3_L$X[  
for(int i=0;i<nStartPos.length;i++) g X8**g'  
{ m/KjJ"s,
 
nStartPos = (long)(i*(nFileLength/nStartPos.length)); @%%bRY  
} e+x*psQ  
for(int i=0;i<nEndPos.length-1;i++) oB3q AP  
{ {[N?+ZJD*L  
nEndPos = nStartPos[i+1]; }eI`
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}
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nEndPos[nEndPos.length-1] = nFileLength; lf;~5/%wMG  
} " C&x,Ic  
} IF^[^^v+H  
xLZMpP5c  
@,GjeF]!  
//启动子线程 tz3]le|ml  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; QWQ!Ak  
for(int i=0;i<nStartPos.length;i++) %L28$c3p  
{ u5/t2}^T  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), r /^'X
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), D|"sE>  
nStartPos,nEndPos,i); h2AGEg'g2[  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 2>ys2:z  
fileSplitterFetch.start(); #*\
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} 5W|u5AIw  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), DYkC'+TEX  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ^b:Xo"q#H  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", we }#Ru*  
nEndPos = " + nFileLength);  Hl!1h%  
// fileSplitterFetch[nPos.length-1].start(); $>|?k$(x  
(%Ng'~J\|  
1"M"h_4  
//等待子线程结束 y>%W;r)  
//int count = 0; nQ!N}5[z'  
//是否结束while循环 /^~p~HKtx  
boolean breakWhile = false; -S
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\?r$&K]4  
while(!bStop) jm4)gmC  
{ sK#H4y+<  
write_nPos(); iY}QgB< M  
Utility.sleep(500); |^>u<E5  
breakWhile = true; IC\E,m  
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for(int i=0;i<nStartPos.length;i++) l<s :%%CX  
{ " S ?Km  
if(!fileSplitterFetch.bDownOver) _dJp 3D  
{ ys/`{:w8p  
breakWhile = false; MkkA{p  
break; F{kG  
} 6|%^pjX5  
} JThk Wx  
if(breakWhile) <xXiJU+  
break; *h>OW  
{`tHJ|8  
vY4WQbz(  
//count++; w4NZt|>5j;  
//if(count>4) pb~Ps#"Zg  
// siteStop(); PkjT&e)  
} is64)2F](  
#)Ep(2  
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System.err.println("文件下载结束！"); )~1.<((<  
} o`oRG)QC  
catch(Exception e){e.printStackTrace ();} 3D{82*&  
} }<E sS  
[5x+aW%ql  
/\6}SG;  
//获得文件长度 H
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public long getFileSize() Dr4
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{ WW)_Wh  
int nFileLength = -1; oZ?IR#^
 
try{ X*_ SHt  
URL url = new URL(siteInfoBean.getSSiteURL()); :8GlyN<E  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); U+:S7z@j?  
httpConnection.setRequestProperty("User-Agent","NetFox"); { +i;e]c  
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=c :lS&B  
int responseCode=httpConnection.getResponseCode(); >ly&+3S  
if(responseCode>=400) "(9=h@@Y"  
{ wa9'2a1?  
processErrorCode(responseCode); ?IL! X-xx  
return -2; //-2 represent access is error Sn;/;^@(\  
} n%7A;l!{  
}w;Q^EU  
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String sHeader; b>GqNf!  
>^M!@=/?J  
I|Vk.,  
for(int i=1;;i++) jB}_Slh1j  
{ :_W0Af09  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Tb>IHoil  
//Utility.log(in.readLine()); 8:;u v7p  
sHeader=httpConnection.getHeaderFieldKey(i); ;}UIj{sj*  
if(sHeader!=null) 3(oZZz  
{ " 8~f  
if(sHeader.equals("Content-Length")) V#n?&-{V  
{ B^E2UNRA  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 8A`p  
break; }dV9%0s!  
} uJ2C+$=Ul  
} \9&YV;Ct  
else :< KSf#O  
break; 6)tB{:h&~0  
} YzforM^F  
} yHa:?u6  
catch(IOException e){e.printStackTrace ();} FCS5@l,'<  
catch(Exception e){e.printStackTrace ();} U'f$YVc  
5$(b3]  
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Utility.log(nFileLength); p,_6jdz  
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return nFileLength; "<g?x`iz  
} ]
%vGC^  
.j'@K+<45  
#dxJ#  
//保存下载信息（文件指针位置） !W+p<F1i  
private void write_nPos() mR!&.R?  
{ Q6s5#7h'"  
try{ yg-L^`t+B5  
output = new DataOutputStream(new FileOutputStream(tmpFile)); x mrugNRg  
output.writeInt(nStartPos.length); WrIL]kJw^  
for(int i=0;i<nStartPos.length;i++) 6Zl.Lh  
{ +73=2.C0  
// output.writeLong(nPos); =:
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output.writeLong(fileSplitterFetch.nStartPos); `\WcF7  
output.writeLong(fileSplitterFetch.nEndPos); ai<MsQQ:=  
} (50[,:#  
output.close(); /ej/&x15  
} A*-]J=:E {  
catch(IOException e){e.printStackTrace ();} ILu0J`;}  
catch(Exception e){e.printStackTrace ();} I8pv:>EhC  
} .f?qUg  
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//读取保存的下载信息（文件指针位置） =+SVzK,+3  
private void read_nPos() YI? C-,  
{ } Y7W1$he  
try{ $9 &Q.Kpq>  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); VDb,$i.Z0  
int nCount = input.readInt(); 8VAYIxRv  
nStartPos = new long[nCount]; T9U2j-lA?  
nEndPos = new long[nCount]; E9Qd>o  
for(int i=0;i<nStartPos.length;i++) 3& fIO  
{ /z.7:<gZ(  
nStartPos = input.readLong(); /I`bh  
nEndPos = input.readLong(); 'Z(MV&  
} Npf7p  
input.close(); 5* o\z&*L  
} T?p`Y| gl  
catch(IOException e){e.printStackTrace ();} yccuTQvz  
catch(Exception e){e.printStackTrace ();} Wzf1-0t  
} t^bdi}[  
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GWA!Ab'<U  
private void processErrorCode(int nErrorCode) mv9E{m  
{ !txELA~24  
System.err.println("Error Code : " + nErrorCode); N.Wdi  
} Ndug9j\2  
a2klOX{  
nDoiG#N0  
//停止文件下载 HqnKpZ  
public void siteStop() N8MlT \+r  
{ #?b^B~ #  
bStop = true; zv
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for(int i=0;i<nStartPos.length;i++) 8KL_PwRX_f  
fileSplitterFetch.splitterStop(); ;ow~vO,x  
7S~9E2N  
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} 44fq1<.K  
} _:fO)gs|1  
//负责部分文件的抓取 -'p@ lk  
**FileSplitterFetch.java gw&#X~em  
*/ r PRuSk-f  
package NetFox; ma]F%E+$  
~QEXB*X-g'  
8.;';[  
import java.io.*; P9tQS"Rs  
import java.net.*; SJ WP8+  
'Kso@St`o  
E23 Yk?"  
public class FileSplitterFetch extends Thread { >fZ/09&3  
\w0b"p  
k1$2a8ja  
String sURL; //File URL /Vm}+"BCS  
long nStartPos; //File Snippet Start Position 2dd:5L,  
long nEndPos; //File Snippet End Position Jn <^Q7N  
int nThreadID; //Thread's ID 8HRPJSO~g  
boolean bDownOver = false; //Downing is over pJ*#aH[ySP  
boolean bStop = false; //Stop identical Oih2UrF  
FileAccessI fileAccessI = null; //File Access interface ("JV:u.L+  
1J{z}yPHc  
gt t
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException w#G=Z_Tt  
{ _AFt6
\  
this.sURL = sURL; %[\Ft  
this.nStartPos = nStart; !qw=I(  
this.nEndPos = nEnd; $qUta<o2@  
nThreadID = id; \gI:`>- x  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 h@m n GE  
} :2UC{_  
b-(UsY:  
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public void run() FskJyB[  
{ ng&EGM  
while(nStartPos < nEndPos && !bStop) 8$
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{ J"2ODB5"  
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c
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try{ WO(&<(?  
URL url = new URL(sURL); C"Y]W-Mgg  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 3Llj_lf  
httpConnection.setRequestProperty("User-Agent","NetFox"); Zqs-I
8y  
String sProperty = "bytes="+nStartPos+"-"; L]}RSE2  
httpConnection.setRequestProperty("RANGE",sProperty); 2bn@:71`  
Utility.log(sProperty); P7k$^n  
k@";i4}A  
gy
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InputStream input = httpConnection.getInputStream(); Ualq>J5-m-  
//logResponseHead(httpConnection); _hyxKrm' 6  
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h^_taAdS`  
byte[] b = new byte[1024]; ,pa&he  
int nRead; |Q)w3\S$  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) M+R)P+  
{ j.'"CU  
nStartPos += fileAccessI.write(b,0,nRead); f~"V  
//if(nThreadID == 1) FvNSu"O~K1  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); GWqY$YT  
} =

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3 cW"VrFy9  
Utility.log("Thread " + nThreadID + " is over!"); g\{! 2
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bDownOver = true; Mm7n?kb6  
//nPos = fileAccessI.write (b,0,nRead); %1?V6&  
} vBYT)S  
catch(Exception e){e.printStackTrace ();} CygV_q
  
} &P{p\v2Y  
} BSu)O~s  
G*~*2>~  
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//打印回应的头信息 ^'I5]cRa  
public void logResponseHead(HttpURLConnection con) M7<#=pX&  
{ @o
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for(int i=1;;i++) o`8+#+@f7  
{ /e?ux~f|  
String header=con.getHeaderFieldKey(i); HJ1\FO9\  
if(header!=null) +$QL0|RL  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); =U7D}n hS-  
Utility.log(header+" : "+con.getHeaderField(header)); 9H%xZ(`vN  
else Y$$?8xr ~  
break; 2l(j 4~g  
} j% USu+&  
} 8(/f!~  
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07"Oj9NlA  
public void splitterStop() W]}V<S$  
{ fQ.>G+0I>  
bStop = true; zcWxyLifl0  
} 7RFkHME  
IS 9q 5/]  
p>tdJjnt  
} d<'Yt|zt  
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s
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/* MHyl=5  
**FileAccess.java 2-c0/?_4  
*//文件访问(定位，写) d~Ry>   
package NetFox; H'\EA(v+  
import java.io.*; bl>b/u7/6  
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public class FileAccessI implements Serializable{ J9=0?^v-:B  
:aqskeT  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 EM w(%}8w  
RandomAccessFile oSavedFile; })SdaZ  
long nPos; T_%]#M  
!K~$-jlT  
yj+b/9My   
public FileAccessI() throws IOException sfPN\^k2  
{ Q!e0Vb  
this("",0); 49fq6ZhO  
} <m:wuNEM  
M*6@1.n  
LbbQ3$@WD  
public FileAccessI(String sName,long nPos) throws IOException {bW3%iU  
{ Dj.+5f'  
oSavedFile = new RandomAccessFile(sName,"rw"); "s<lLgi  
this.nPos = nPos; _O,ZeES  
oSavedFile.seek(nPos); Jv.R?1;8i  
} UBHQzc+,  
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4^ 6L])y  
public synchronized int write(byte[] b,int nStart,int nLen) Tn-]0hWkP  
{ ]]o[fqD-Zn  
int n = -1; 
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try{ B]F7t4Y!  
oSavedFile.write(b,nStart,nLen); "I FGW4FnL  
n = nLen; PM>
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} AHD%6 \$  
catch(IOException e) hBE>ea  
{ []!r|R3  
e.printStackTrace (); YY~=h5$  
} `#8R+c=$  
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* .VZ(wX  
return n; 1+}Ud.v3VW  
} ~'.yhPog  
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9?$!=4  
} RAbq_^Q  
%<|KJb4?  
m e{SVG{  
/* HWOH8q{f!  
**SiteInfoBean.java K61os&K  
*/ N4jLb
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package NetFox; BQ0\+  
=T}uQ$X  
J4#]8!A  
public class SiteInfoBean { xumv I{  
 "1Aus  
8mLU ~P |  
private String sSiteURL; //Site's URL `3oP^#  
private String sFilePath; //Saved File's Path :?k=Yr  
private String sFileName; //Saved File's Name lFY8^#@  
private int nSplitter; //Count of Splited Downloading File A'(F%0NF6  
h18y?e7MU  
U/o}{,$A  
public SiteInfoBean() Nb/%>3O@  
{//nSplitter的缺省值为5 i]?xM2(N  
//default value of nSplitter is 5 17MjIX  
this("","","",5); Qo *]l_UO;  
} ACltV"dB^  
}*R6p?L5  
9W$)W  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) eJp-s" %  
{ 9'h^59  
sSiteURL= sURL; !OgoV22  
sFilePath = sPath; [`\Qte%UH  
sFileName = sName; 'FFc"lqj  
this.nSplitter = nSpiltter; :K:gyVrC  
.Kwl8xRg  
%([H*sLX  
} *=@pdQkR  
0|;=mYa4M  
rNyK*Wjt  
public String getSSiteURL() MV\zwH  
{ TLgVuY  
return sSiteURL; p n>`v  
} R,1,4X
T  
^0-=(JrC  
pk1M.+  
public void setSSiteURL(String value) hiHp@"l<  
{ ?='9YM  
sSiteURL = value; 1tpD|  
} #sZes  
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&[5az/Hj*  
public String getSFilePath() L{p-'V  
{ ht9b=1wd%s  
return sFilePath; H]X)@n>  
} EPy/6-5b  
hGV/P94  
Q#KjX;No  
public void setSFilePath(String value) 4/>={4Y9  
{ lej{VcG  
sFilePath = value; 0{F.DDiNT  
} glgk>83I+  
Y\sjm]_  
UXHFti/A<  
public String getSFileName() @1@WB]mQQ  
{ tO3 ;;%  
return sFileName; 063
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} e,8-P-h~T  
cC.DBYV+-  
R0}%   
public void setSFileName(String value) sXu+F2O  
{ dZmq  
sFileName = value; y>8?RX8  
} q3`t0eLZ  
vE(Hy&Q&  
Dzr5qP?#  
public int getNSplitter() jq{
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{ {AUEVt  
return nSplitter; )K~nZLULY  
} ]mA?TwD  
YyIt-fPZ  
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public void setNSplitter(int nCount) `l#g`~L  
{ 8t%1x|!  
nSplitter = nCount; )3sb2 #  
} mN02T@R-  
} za7wNe(s  

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/* C.<4D1}P  
**Utility.java bAp`lmFI  
*/ \ua.%|  
package NetFox; :xCobMs_/  
ny=iAZM>q  
F1>,^qyG6  
public class Utility { 9lv2  
x}d\%*B  
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public Utility() s8Oz^5p(  
{ #SueT"F  
WM
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1~
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} ~\P.gSiz  
1 <+^$QL  
//线程睡眠 mLE`IKgd]  
public static void sleep(int nSecond) =xoTH3/,>  
{ 7|rT*-Ia  
try{ 1o%Hn"uG
 
Thread.sleep(nSecond); 7f>n`nq?  
} rtm28|0H'  
catch(Exception e) 4hIC&W~f  
{ t At+5H  
e.printStackTrace (); kWFR(J&R  
}
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y  
} K4BMa]/U  
S[M$>  
//日志 \X!!(Z;6A  
public static void log(String sMsg) P;Ox|  
{ WlUE&=|Oz2  
System.err.println(sMsg); #Z :r  
} xpz Jt2S  
P}gh-5x  
#LiC@>  
public static void log(int sMsg) \Z8!iruN  
{ \B)<<[ $  
System.err.println(sMsg); wr`eBPu  
} v|6fqG+Q\  
} N*fN&0r  

?=/l@d  
C$8=HM3  
/* e 6*=Si}V  
**TestMethod.java *3|KbCX  
*/ # V+e  
package NetFox; * 7CI q  
_),@^^&x  
A Ho<E"R\  
public class TestMethod { eIJQ|p<v  
vJ!t.Vou  
R-ci?7dt3  
public TestMethod() /-T%yuU  
{ ///xx/weblogic60b2_win.exe lI9 3{!+>  
try{ y03l_E,  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); c!zu0\[Id  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); W8)GT`\  
SiteFileFetch fileFetch = new SiteFileFetch(bean); n):VuOjm  
fileFetch.start(); Ap/WgVw;  
} D+OkD-8q  
catch(Exception e){e.printStackTrace ();} FwyPmtBj  
]l`DR4 =  
2bqwnRT}  
} VrpYBU  
{PZe!EQ  
3iB8QO;pp  
public static void main(String[] args) Nbr{)h  
{ `g7' )MSy  
new TestMethod(); Ks4TBi&J   
} nN[,$`JD,  
} [yz;OoA:;  
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