http断点续传简单实现（java)

/* hYQ%|CBXBR  
**SiteFileFetch.java ku8Z;ONeH  
*/  6}ewBAq%  
package NetFox; mTu9'/$(  
import java.io.*; ]-]@=qYu  
import java.net.*; e5y`CXX  
#nL0Hx7]E  
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public class SiteFileFetch extends Thread { ;5S7_p2]j  
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SiteInfoBean siteInfoBean = null; //文件信息Bean B3=/iOb#  
long[] nStartPos; //开始位置 )%W2XvG  
long[] nEndPos; //结束位置 z~;qDf|I  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 sm <kb@g  
long nFileLength; //文件长度 %=>x
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boolean bFirst = true; //是否第一次取文件 }Qu 7o  
boolean bStop = false; //停止标志 aj~@r3E;  
File tmpFile; //文件下载的临时信息 :D7!6}%  
DataOutputStream output; //输出到文件的输出流 JVYYwA^.  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 7Et(p'  
public SiteFileFetch(SiteInfoBean bean) throws IOException BNUf0;
 
{ =hb87g.  
siteInfoBean = bean; h(K4AiGE  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); (8/xSOZ[  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); p5w g+K  
if(tmpFile.exists ()) UeTp,  
{ >sY+Y22U  
bFirst = false; EnAw8Gm*  
read_nPos(); ;0{*V5A  
} 6XqO'G  
else X~b+LG/  
{ b .@dUuKz-  
nStartPos = new long[bean.getNSplitter()]; "lAS <dq  
nEndPos = new long[bean.getNSplitter()]; .;Yei6H  
} +#9 (T  
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} uQ)]g  
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public void run() )8PL7P84  
{ A>S2BL#=  
//获得文件长度 l;i u`  
//分割文件 cE?
J]5#^  
//实例FileSplitterFetch I<f M8t.Y>  
//启动FileSplitterFetch线程 >@W#@W*I@  
//等待子线程返回 KLB?GN?Pb  
try{ ax}Xsk_  
if(bFirst) ]P5u:~U  
{

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nFileLength = getFileSize(); YkbLf#2AE|  
if(nFileLength == -1) u{^Kyo#v  
{ H2-
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System.err.println("File Length is not known!"); bBL"F!.  
} }3e+D  
else if(nFileLength == -2) \6L=^q=  
{ P40eK0e6  
System.err.println("File is not access!"); S d -+a  
} *8+YR  
else ru L
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{ }
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for(int i=0;i<nStartPos.length;i++) b?,y%D)'  
{ AG%aH=TKp  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); /qr
8  
} l1-FL-1  
for(int i=0;i<nEndPos.length-1;i++) >^}z  
{ C5?M/xj  
nEndPos = nStartPos[i+1];
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} 6=D;K.!  
nEndPos[nEndPos.length-1] = nFileLength; *a4eL [  
} U^I'X7`r  
} C7:Ry)8'I  
0>Nq$/!  
iddT.   
//启动子线程 $cedO']  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; v'=APl+_  
for(int i=0;i<nStartPos.length;i++) )i>KgX  
{ BGS6uV4^>  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ~b/>TKn+  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), mB`r6'#=  
nStartPos,nEndPos,i); &,xM;8b  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 7v_e"[s~  
fileSplitterFetch.start(); A>k;o0r  
} 1lM0pl6M  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), oB@C-(M  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); h !1c(UR  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", {I ,
'  
nEndPos = " + nFileLength); g*uO IF  
// fileSplitterFetch[nPos.length-1].start(); 1d6pQ9 N  
|ouk;r24V  
Uw!v=n3#!  
//等待子线程结束 WF7RMQ51j  
//int count = 0; 8jk*N  
//是否结束while循环 J\BdC];  
boolean breakWhile = false; =W=%!A\g  
#</yX5!V  
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while(!bStop) C}Q2UK-:  
{ 2I  
write_nPos(); 195(Kr<5$  
Utility.sleep(500); $qqusa}`K  
breakWhile = true; [%pZM.jFO  
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+  
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for(int i=0;i<nStartPos.length;i++) f~Su F,o@h  
{ O(VV-n7U  
if(!fileSplitterFetch.bDownOver) X"]ZV]7(]s  
{ 'n=D$j]X  
breakWhile = false; }Z|a?J@CZm  
break; slbV[xR  
} ~F-,Q_|-  
} gQ[4{+DSf  
if(breakWhile)
%WR  
break; - U|4`{PP  
s]qfLC  
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b<  
//count++; ur|2FS7  
//if(count>4) hI yfF  
// siteStop(); %k~=iDk@  
} iDA`pemmi&  
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System.err.println("文件下载结束！"); Hs9uDGWp  
} RB!g
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catch(Exception e){e.printStackTrace ();} Gu-Sv!4p  
} *,(`%b[  
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/i<g>*82  
//获得文件长度 [3s~Z8 pP  
public long getFileSize() nz(OHh!}u  
{ `'/8ifKz  
int nFileLength = -1; Z-p_hNb  
try{ \Z$*8z=  
URL url = new URL(siteInfoBean.getSSiteURL()); n~h%K7 c  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); @AwH?7(b  
httpConnection.setRequestProperty("User-Agent","NetFox"); |7argk+  
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int responseCode=httpConnection.getResponseCode(); :JlJB  
if(responseCode>=400) eNNK;xXe#  
{ zK&`&("4C  
processErrorCode(responseCode); Je/R'QP^8  
return -2; //-2 represent access is error Y<B| e91C  
} ^l9S5 {  
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String sHeader; ?^hC|IR$  
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for(int i=1;;i++) ojaZC,}  
{ B
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//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); gP}M\3-O  
//Utility.log(in.readLine()); ,T]okN5uI  
sHeader=httpConnection.getHeaderFieldKey(i); $I.'7 &h;  
if(sHeader!=null) FY'f{gD^  
{ MKbW^:  
if(sHeader.equals("Content-Length")) a^22H  
{ -6?5|\  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); @c/~qP4  
break; o,29C7Ii  
} @'S-nn,sO  
} y,aASy!Q  
else /+rHy7(\  
break; .e6:/x~p*  
} O_E[FE:+  
} {AZW."?  
catch(IOException e){e.printStackTrace ();} az w8BK  
catch(Exception e){e.printStackTrace ();} 51~:t[N|  
@~"0|,6VC  
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Utility.log(nFileLength); P^ a$?  
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return nFileLength; 8NLk`/  
} Eq|_>f@@8  
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//保存下载信息（文件指针位置） rn(
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private void write_nPos() [u<1DR  
{ ?xy~N?N  
try{ v8LKv`I's  
output = new DataOutputStream(new FileOutputStream(tmpFile)); )0NA*<Q+.  
output.writeInt(nStartPos.length); us/x.qPy2  
for(int i=0;i<nStartPos.length;i++) n04Zji(F@  
{ 7y:J@fh<  
// output.writeLong(nPos); 5[0n'uH  
output.writeLong(fileSplitterFetch.nStartPos); wL:3RZB  
output.writeLong(fileSplitterFetch.nEndPos); 8^O|Aa$IF:  
} 4YKb~1qkk  
output.close(); oM< 9]jK}  
} 3o z]  
catch(IOException e){e.printStackTrace ();} [z?<'Tj  
catch(Exception e){e.printStackTrace ();} #SO9e.yhI  
} 2
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//读取保存的下载信息（文件指针位置） f7mI\$CN  
private void read_nPos() ^)X^Pcx  
{ [~x Ql  
try{ Oq[tgmf  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); CYz]tv}g:  
int nCount = input.readInt(); 4/$]wK`  
nStartPos = new long[nCount]; 3^8%/5$v  
nEndPos = new long[nCount]; CT/`Kg_  
for(int i=0;i<nStartPos.length;i++) a6[bF  
{ Jcm"i~  
nStartPos = input.readLong(); ^"l4  
nEndPos = input.readLong(); /KH3v!G0  
} dqcf
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input.close(); s@0#w*N  
} r6"t`M  
catch(IOException e){e.printStackTrace ();} [gU z9iU  
catch(Exception e){e.printStackTrace ();} EyozhIV  
} i: 1V\q%  
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o[_{\  
private void processErrorCode(int nErrorCode) ?!b}Ir<1j
 
{ UL(#B TK  
System.err.println("Error Code : " + nErrorCode); $6R<)]6  
} |NL$? %I  
^ygN/a>rr  
eQA89 :j,  
//停止文件下载 xCGvLvFn  
public void siteStop() k}~|jLu@g  
{ f~9
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bStop = true; @va6,^)  
for(int i=0;i<nStartPos.length;i++) 7|*|xLrVY  
fileSplitterFetch.splitterStop(); ]^R;3kU4Q  
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} wtaeF+u-R-  
} *joM[ML` 6  
//负责部分文件的抓取 iN<Tn8-YH6  
**FileSplitterFetch.java a>6!?:Rj  
*/ *SLv$A  
package NetFox; 5s`NR<|2L  
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import java.io.*; d-lC|5U%  
import java.net.*; p^^
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public class FileSplitterFetch extends Thread { J1hc :I<;  
*o`bBdZ  
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String sURL; //File URL u<:
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long nStartPos; //File Snippet Start Position "4zTP!Ow  
long nEndPos; //File Snippet End Position }"E?#&^  
int nThreadID; //Thread's ID !Hxx6/  
boolean bDownOver = false; //Downing is over P'
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boolean bStop = false; //Stop identical 7C F
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FileAccessI fileAccessI = null; //File Access interface ?FxxH*>"  
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}qRYXjS  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException bR(rZu5  
{ H4MFTnJ{  
this.sURL = sURL; d?.e
wsC  
this.nStartPos = nStart; 8W9kd"=U  
this.nEndPos = nEnd; Y 8EL  
nThreadID = id; 8N'[)Jw  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 n'K,*  
} 3t)07(x_B  
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!SMIb(~[z  
public void run() 4,`Yx s)%  
{ XnV*MWv  
while(nStartPos < nEndPos && !bStop) k7'_  
{ "l"zbW WOH  
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try{ KQ9~\No]  
URL url = new URL(sURL); W c{<DE?J  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); )k&<D*5s  
httpConnection.setRequestProperty("User-Agent","NetFox"); \GO^2&g(  
String sProperty = "bytes="+nStartPos+"-"; S=*rWh8)%<  
httpConnection.setRequestProperty("RANGE",sProperty); 7LbBS:@3z_  
Utility.log(sProperty); hQv~C4Wfrf  
79^Y^.D  
_8v8qT}O~4  
InputStream input = httpConnection.getInputStream(); >,yE;zuw  
//logResponseHead(httpConnection); tt$DWmm  
9@9(zUS|  
,6uON@  
byte[] b = new byte[1024]; |#^wYZO1U  
int nRead; iimTr_TEt  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) C4Z}WBS(  
{ 9nN$%(EO5;  
nStartPos += fileAccessI.write(b,0,nRead); _0Qp[l-  
//if(nThreadID == 1) 2v\,sHw+-  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); `q@5d&d`j  
} 0z1m!tr  
.B_LQ;0:   
|3<tDq@+  
Utility.log("Thread " + nThreadID + " is over!"); 0K<y }  
bDownOver = true; 5|z>_f.^pS  
//nPos = fileAccessI.write (b,0,nRead); >x]b"@Hkw  
} CoO..  
catch(Exception e){e.printStackTrace ();} gi\2bzWkbX  
} S~X&^JvT  
} ~)xg7\k  
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,@!io  
//打印回应的头信息 {]BP
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public void logResponseHead(HttpURLConnection con) ek\8u`GC  
{ +i HZ*  
for(int i=1;;i++) z~fZg6  
{ +GqK$B(x7  
String header=con.getHeaderFieldKey(i); 'Z5l'Ac  
if(header!=null) 7)SG#|v[$  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ]/g&y
5RG  
Utility.log(header+" : "+con.getHeaderField(header)); wFI2(cQ  
else K9O%SfshF  
break; xVw9_il2a  
} 5#|D1A  
} tUU`R{=(  
8S/SXyS  
*'[8FZ|dQ  
public void splitterStop() @-ps[b`z  
{ Hj(ay4
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bStop = true; Lu?MRF f  
} G%5bQ|O  
@D1}).  
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} r{2V`h1/|  
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l ld,&N8  
/* T6mbGE*IeE  
**FileAccess.java pV:;!+  
*//文件访问(定位，写) KTLq~Ru  
package NetFox; RBuerap  
import java.io.*; d?[gd(O  
0#Ivo<V  
_C"=Hy{  
public class FileAccessI implements Serializable{ +\Uq=@  
4f~ c#0?  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 /Q]6"nY  
RandomAccessFile oSavedFile; ,j
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long nPos; 3T1t !q4/5  
m{#?fR=9  
;|yd}q=p  
public FileAccessI() throws IOException @}K|/  
{ n0)0"S|y1  
this("",0); S:5vC{  
} ]? 2xS?vd  
\G4L+Q/13  
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public FileAccessI(String sName,long nPos) throws IOException 0nOkQVMk>  
{ SfTTB'9  
oSavedFile = new RandomAccessFile(sName,"rw");  _"0,  
this.nPos = nPos; KYw~(+gHv2  
oSavedFile.seek(nPos); 0c}pg:XT  
} R;d)I^@  
0+3_CS++r  
>;qAj!'  
public synchronized int write(byte[] b,int nStart,int nLen) Q' b@5o  
{
,i]X^z5!  
int n = -1; I}^Q u0ub  
try{ r,cz yE/  
oSavedFile.write(b,nStart,nLen); `|
uwR5  
n = nLen; uy'I#^Bt  
} ;r8< Ed
  
catch(IOException e) OKo)p`BX  
{ QH>e_  
e.printStackTrace (); Th.Mn}1%L  
} RKi11z  
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return n; C\`*_t  
} |(eRv?Qy@  
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} #3~hF)u&/  
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/* y@Gl'@-O  
**SiteInfoBean.java 3*(w=;y  
*/ 57|RE5]|!  
package NetFox; 1ze\ U>  
@LyCP4  
BT*z^ZH  
public class SiteInfoBean { (_0r'{`  
e'l@M$^  
q 3nF\Me0  
private String sSiteURL; //Site's URL l/i7<q  
private String sFilePath; //Saved File's Path x*#9\*@EI  
private String sFileName; //Saved File's Name N\{{:<Cp\  
private int nSplitter; //Count of Splited Downloading File <sncW>?!~  
?y/LMja  
#@UzOQ>  
public SiteInfoBean() aam6R/
4  
{//nSplitter的缺省值为5 S"<"e\\}"_  
//default value of nSplitter is 5 ?9Hs,J  
this("","","",5);
O~*`YsL9  
} P->.eo#VG  
hU|TP3*  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ']&rPvkL  
{ fbrCl!%P  
sSiteURL= sURL; }!_o
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sFilePath = sPath; (hzN(Dh  
sFileName = sName; "n!yK
  
this.nSplitter = nSpiltter; i/ilG3m>  
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/9w>:i81  
} AC) M2;  
7Gc{&hp*  
d,"LZ>hNY*  
public String getSSiteURL() l]R0r{{  
{ ATNOb  
return sSiteURL; *glZb;_  
} []>'Dw_r  
I0)`tQ+  
KQdIG9O+6  
public void setSSiteURL(String value) $1an#~  
{ _IDZ.\'>$  
sSiteURL = value; =?fz-HB  
} $<^t][{  
W7i|uTM  
t;&XIG~  
public String getSFilePath() ,S8K!  
{ <\aeC2~M  
return sFilePath; =Ph8&l7~sp  
} ut{T:kT  
j9+$hu#a  
p T(M>LP83  
public void setSFilePath(String value) Ux[<g%F"  
{ V2YK T,5  
sFilePath = value; _IYaMo.n  
} %BqaVOKJ"f  
k9^Hmhjw  
0s#72}n  
public String getSFileName() ,5}U H  
{ |\5^ub,m  
return sFileName; 0lfK} a  
} tMIYVHGy  
]A#lV$  
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public void setSFileName(String value) \hB BG8=
&  
{ `2s!%
/  
sFileName = value; +K57. n{  
} 'rD6MY  
La26"C"X  
P3$eomX'  
public int getNSplitter() wl Oeoi  
{ tli.g  
return nSplitter; )ZJvx%@i  
} /Rp]"S vt  
[I $+wWW_  
C|
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public void setNSplitter(int nCount) nV;'UpQw  
{ AKNx~!%2  
nSplitter = nCount; bf3!|Um  
} L"L3n,%F  
} mCtS_"W  
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)&DAbB!O  
/* =BsV`p7rU  
**Utility.java +jN}d=N-  
*/ f0Q6sVZHa  
package NetFox; dj|5'<l2  
]|;+2@kDR  
da{]B5p\  
public class Utility { $EMOz=)I#  
s:`i~hjq  
85{m+1O~  
public Utility() H#-3  
{ I-7LT?r  
.b:!qUE^  
$|4C]Me (  
} l?Y^3x}j  
t<%0eu|  
//线程睡眠 8Of
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public static void sleep(int nSecond) '[F:uA  
{ +)T
e)^&v%  
try{ 1C[9}}  
Thread.sleep(nSecond); y!e]bvN  
} }fpya2Xt  
catch(Exception e) fGgt[f[  
{ ajbe7#}  
e.printStackTrace (); ijI/z5  
} k15vs  
} )fH Q7  
-!\3;/  
//日志 \?:L>-&h8  
public static void log(String sMsg) T?9D?u?]  
{ *P()&}JK  
System.err.println(sMsg);
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} @0`A!5h?u  
TFVQfj$r  
&}ZmT>q`$  
public static void log(int sMsg) N,ht<l\  
{ > =>/~dIb  
System.err.println(sMsg); ,m=F H?5  
}  K +7  
} H/8^Fvd  
]5W$EvZ9)  
lwnO  
/* }ze+ tf  
**TestMethod.java wak26W>I3  
*/ x_PO;  
package NetFox; A#uU]S  
WlL(NrVA@@  
l,wlxh$}(  
public class TestMethod { tz1@s nes  
(su,=Z  
b`0tfXzS5  
public TestMethod() KaIKb=4L|  
{ ///xx/weblogic60b2_win.exe gW,
[X(  
try{ 5'lVh/  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 0V%c%]PH  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 6K2e]r  
SiteFileFetch fileFetch = new SiteFileFetch(bean);  *7Dba5B  
fileFetch.start(); $QX$rN  
} @xG&K{j  
catch(Exception e){e.printStackTrace ();} Z\$HgG  

f^%3zWp|-  
(1/Sf&2i  
} OhF55,[  
DF%d/a{]  
3)OZf{D[  
public static void main(String[] args) #86N !&x  
{ %cNN<x8  
new TestMethod(); ;5a$OM  
} mrGV{{.  
} -15e  
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