http断点续传简单实现（java)

/* T~4N+fK  
**SiteFileFetch.java yuhnYR\`m  
*/ XYrJ/!*.  
package NetFox; )"+2Z^1-  
import java.io.*; $?P22"/p  
import java.net.*; 6#@ f'~s  
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public class SiteFileFetch extends Thread { &#yR;{  
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SiteInfoBean siteInfoBean = null; //文件信息Bean nh>K`+>co  
long[] nStartPos; //开始位置 cV{o?3<:B  
long[] nEndPos; //结束位置 m3<+yz$!r  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 oXXC@[??}N  
long nFileLength; //文件长度 2*iIjw3g  
boolean bFirst = true; //是否第一次取文件 $*R/tJ.  
boolean bStop = false; //停止标志 {0"YOS`3AX  
File tmpFile; //文件下载的临时信息 *%/~mSx  
DataOutputStream output; //输出到文件的输出流 ^-z=`>SrS"  
W ~f(::  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） H<EQu|f&x  
public SiteFileFetch(SiteInfoBean bean) throws IOException \>QF(J [8  
{ GL{57  
siteInfoBean = bean; /3B $(  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); re?s.djT  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ~{,X3-S_H  
if(tmpFile.exists ()) 6/V3.UP-  
{ y:m_tv0~0  
bFirst = false; e]=lKxFh&l  
read_nPos(); a^d8I  
} :j }fC8'  
else zOgTQs"ZH  
{ 03E4cYxt5  
nStartPos = new long[bean.getNSplitter()]; 4k-+?L!/G  
nEndPos = new long[bean.getNSplitter()]; YjOs}TD lx  
} ' Z0r>.  
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} jO*l3:!~\  
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public void run() :0& X^]\  
{ k@ZLg9  
//获得文件长度 YQJ==C1  
//分割文件 yeDsJ/L  
//实例FileSplitterFetch ^V$Ajt  
//启动FileSplitterFetch线程 ivDGZI9  
//等待子线程返回 ;{h CF  
try{ +6wiOHB`  
if(bFirst) ,C%eBna4Iq  
{ EI!6MC)  
nFileLength = getFileSize(); < -W*$?^  
if(nFileLength == -1) MUfG?r\t  
{ Q'_z<V  
System.err.println("File Length is not known!"); `\Hf]b  
} A+hT3;lp  
else if(nFileLength == -2) $/!{OU.t`  
{ H"ZZ.^"5FV  
System.err.println("File is not access!"); 5p.rwNE  
} 7qTE('zt  
else "BX!  
{ EdZ\1'&/9  
for(int i=0;i<nStartPos.length;i++) U- )i+}Ng  
{ J{^RkGF  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); E4m`  
} C4TE-OM8  
for(int i=0;i<nEndPos.length-1;i++) Y"A/^]   
{ UfS%71l.$  
nEndPos = nStartPos[i+1]; p+)YTzzc  
} ~3uP6\F  
nEndPos[nEndPos.length-1] = nFileLength; V<k8N^  
} C8z{XSo  
} o,|[GhtHqs  
[1.+HyJ}  
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//启动子线程 UTXSeNP  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; OS8q( 2z?s  
for(int i=0;i<nStartPos.length;i++) (?nCyHC%g  
{ 0RoU}r@z4  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ^Q+g({  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), /0Ax*919j  
nStartPos,nEndPos,i); Z+@2"%W  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); E Cyyl  
fileSplitterFetch.start(); U8 nH;}i  
} +TXX$)3%  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), "etPT@gF  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); j~*L~7  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 8#vc(04(  
nEndPos = " + nFileLength); / X1 x  
// fileSplitterFetch[nPos.length-1].start(); _a1x\,R|DB  
N<~ku<nAU  
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//等待子线程结束 F_CYYGZ  
//int count = 0; +SwR+H)?  
//是否结束while循环 JQ"U4GVp  
boolean breakWhile = false; ~6p[El#tS  
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while(!bStop) *QH28%^  
{ ynbuN x*  
write_nPos(); t.;LnrY  
Utility.sleep(500); ~?(N  
breakWhile = true; r?/'!!4  
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for(int i=0;i<nStartPos.length;i++) 2k=#om19  
{ <i,U )Tt^C  
if(!fileSplitterFetch.bDownOver) A{A\RSZ0  
{ ?!+MM&c-n  
breakWhile = false; [UH||qW  
break; NX}<*
b/  
} R6(oZph  
} 9g<7i  
if(breakWhile) EKO[!,  
break; AB4(+S*LA  
:8OZ#D_Hl  
M]J^N#  
//count++; HPZ}*m'  
//if(count>4) Ft
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// siteStop(); ')$+G152  
} 4qk9NK2 U  
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System.err.println("文件下载结束！");  a24"yT  
} o7$'cn  
catch(Exception e){e.printStackTrace ();} !4X f~P  
} I"ok&^t^}  
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//获得文件长度 5rU[Tir  
public long getFileSize() :>C2gS@  
{ 0.@&_XTPl  
int nFileLength = -1; "/wyZ  
try{ y2^Y/)   
URL url = new URL(siteInfoBean.getSSiteURL()); =o$sxb E(  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); +8R
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httpConnection.setRequestProperty("User-Agent","NetFox"); VcXq?f>\  
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int responseCode=httpConnection.getResponseCode(); V)[@98T_4?  
if(responseCode>=400) j3{D^|0bP  
{ yjF1}SQ  
processErrorCode(responseCode); N u<_}  
return -2; //-2 represent access is error $adbCY\  
} 6V7B;tB  
)!P)U(*v  
:qd`zG3  
String sHeader; T[g[&K1Y  
5?]hd*8  
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for(int i=1;;i++) _I:/ZF5  
{ f,kZ\Ia'r  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ']2E {V  
//Utility.log(in.readLine()); ;6>2"{N
W  
sHeader=httpConnection.getHeaderFieldKey(i); ]7Tkkw$  
if(sHeader!=null) YTUZoW2  
{ 7+\+DujE$  
if(sHeader.equals("Content-Length")) =4FXBPoQK  
{ xHD=\,{ig  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 2#c<\s|C  
break; OCBgR4I  
} JzQ)jdvp  
} uM_wjP  
else @`q:IIgW  
break; EK6:~  
} Bu#VMkchJ  
} 6\g cFfo  
catch(IOException e){e.printStackTrace ();} 7$CBx/X50)  
catch(Exception e){e.printStackTrace ();} HTX?,C_  
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u  
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Utility.log(nFileLength); wea-zN  
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return nFileLength; --$ 4Q(#  
} ;DFSzbF`  
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//保存下载信息（文件指针位置） 1_PoqD!q  
private void write_nPos() ;:\<gVi:  
{ <G|(|E1  
try{ >\KNM@'KI  
output = new DataOutputStream(new FileOutputStream(tmpFile)); u{['<r;I  
output.writeInt(nStartPos.length); UQ?XqgUM  
for(int i=0;i<nStartPos.length;i++) Ya3C#=  
{ F8jd'OR  
// output.writeLong(nPos); -p]1=@A<}  
output.writeLong(fileSplitterFetch.nStartPos); I|
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output.writeLong(fileSplitterFetch.nEndPos); &$`P,i 1)  
} F\KjEl0  
output.close(); vq(0OPj8r[  
} aX)I3^ar  
catch(IOException e){e.printStackTrace ();} gG<~-8uQ  
catch(Exception e){e.printStackTrace ();} M2OIBH4!  
} !dyXJQ  
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//读取保存的下载信息（文件指针位置） ON=@O  
private void read_nPos() 7%Gwc?[x  
{ J??-j  
try{ J:CXW%\ <q  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); K1 EynU I  
int nCount = input.readInt(); I>]oS(GNT  
nStartPos = new long[nCount]; [>8}J"  
nEndPos = new long[nCount]; k/#&qC>]  
for(int i=0;i<nStartPos.length;i++) #`CA8!j!!  
{ f
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nStartPos = input.readLong(); 7puFz4+f  
nEndPos = input.readLong(); ObVGV  
} X[]m _@v  
input.close(); G_bG  
} We$:&K0  
catch(IOException e){e.printStackTrace ();} n}F&1Z  
catch(Exception e){e.printStackTrace ();} 3!XjtVhK?I  
} de.&`lPRf  
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private void processErrorCode(int nErrorCode) l{I6&^!KS  
{ ($au
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System.err.println("Error Code : " + nErrorCode); Cl;oi}L  
} Rdvk ml@@  
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//停止文件下载 Q sZx) bO  
public void siteStop() dP#|$1  
{ JD)(oK%C  
bStop = true; <*16(!k0  
for(int i=0;i<nStartPos.length;i++) {> eXR?s/  
fileSplitterFetch.splitterStop(); mn, =i  
}zkHJxZgE  
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} I4/8 _)b^  
} "6MVvpy"  
//负责部分文件的抓取 QdT}wkX  
**FileSplitterFetch.java z>58dA@f  
*/ N60rgSzI  
package NetFox; _4"mAPt  
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import java.io.*; sF!($k;!  
import java.net.*; G_;)a]v8)  
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public class FileSplitterFetch extends Thread { 2D75:@JL}|  
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7!@-*/|!S9  
String sURL; //File URL EYtL_hNp}I  
long nStartPos; //File Snippet Start Position 4 !i
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long nEndPos; //File Snippet End Position wQqb`l7+  
int nThreadID; //Thread's ID .{ocV#{
s  
boolean bDownOver = false; //Downing is over j
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boolean bStop = false; //Stop identical msP{l^%0  
FileAccessI fileAccessI = null; //File Access interface UtPLIal  
!}YAdZJ  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException [B+yyBtx  
{ JJP08oP  
this.sURL = sURL;
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this.nStartPos = nStart; ]$ L|  
this.nEndPos = nEnd; 'n{Nvt.c  
nThreadID = id; 7&t-pv92*  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 <'qeXgi  
} {@eJtF+2  
1C<uz29  
>p)MawT]  
public void run() l1T m`7}  
{ 7E!IF>`  
while(nStartPos < nEndPos && !bStop) ^8 zR  
{ rf $QxJ  
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try{ 4" Cb/y3  
URL url = new URL(sURL); "S8uoSF`>  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); "fG8?
)d;  
httpConnection.setRequestProperty("User-Agent","NetFox"); n!YKz"$  
String sProperty = "bytes="+nStartPos+"-"; !TA

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httpConnection.setRequestProperty("RANGE",sProperty); f%SZg!+t  
Utility.log(sProperty); DK$X2B"cV  
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InputStream input = httpConnection.getInputStream(); >"|B9Woc  
//logResponseHead(httpConnection); I;e=0!9U  
\n$u)Xj~6^  
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byte[] b = new byte[1024]; W#^2#sjO  
int nRead; 0t Fkd  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ^A!Qc=#
z}  
{ ;T"zV{;7BR  
nStartPos += fileAccessI.write(b,0,nRead); _"E%xM*r  
//if(nThreadID == 1) E)TN,@%  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 6VS4y-N  
} ~D<IB#C  
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Utility.log("Thread " + nThreadID + " is over!"); T ?$:'XJ  
bDownOver = true; 5]NqRI^0  
//nPos = fileAccessI.write (b,0,nRead); {9?
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} uD}2<$PP  
catch(Exception e){e.printStackTrace ();} fm
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} iL7DRQ1  
} R9'b-5q  
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//打印回应的头信息 kO,zZF&  
public void logResponseHead(HttpURLConnection con) V}J)\VZ2#  
{ <vUbv  
for(int i=1;;i++) Z3#P,y9@  
{ U}6B*Xx'  
String header=con.getHeaderFieldKey(i); 6ys &zy  
if(header!=null) 4A8;tU$&  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); G'oG</A  
Utility.log(header+" : "+con.getHeaderField(header)); S0B|#O%Z  
else 4,sJE2"[9  
break; ]Y%Vio  
} 9`1O"R/  
} .LZwuJ^;  
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public void splitterStop() 4[.oPK=i  
{ 4[;X{ !  
bStop = true; F<L EQ7T  
} ZG>PQA  
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}j^i}^Du,  
} N9jH\0nG  
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7Nk!1s
:  
/* }RzWJ@QD<  
**FileAccess.java xC{qV,  
*//文件访问(定位，写) xfpa
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package NetFox; ,5|&A  
import java.io.*; **$LR<L  
)we}6sE"  
v:!Z=I}>  
public class FileAccessI implements Serializable{ A;*d}Xe&J  
S#MZV@nGF  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 PMNjn9d  
RandomAccessFile oSavedFile; M!/Cknm  
long nPos; ]!I7Y.w6  
$*AYcy7  
n&"B0ycF  
public FileAccessI() throws IOException P,xKZ{(  
{ +_; l|uhT;  
this("",0); -n=^U  
} Ont%eC\  
`}(b2Hc>  
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public FileAccessI(String sName,long nPos) throws IOException e8pG"`wM8  
{ F ~^Jmp7Y  
oSavedFile = new RandomAccessFile(sName,"rw"); qyF{f8pzq  
this.nPos = nPos; luo  
oSavedFile.seek(nPos); '^No)n\`  
} O_ChxX0KP  
QWD'!)Zb  
-*$HddD  
public synchronized int write(byte[] b,int nStart,int nLen) L\@I*QP  
{ UJM1VAJ0  
int n = -1; V8rx#H~  
try{ fDT%!  
oSavedFile.write(b,nStart,nLen); W8ouO+wK  
n = nLen; `-(|>5wWS  
} :pGaFWkvO  
catch(IOException e) Ove<mFI\  
{ l|/ep:x8  
e.printStackTrace (); 7s/u(~d)  
} .@(6Y
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^lA=* jY(  
return n; ~F4fFQ-yy  
} qAn!RkA  
pi Z[Y 5OE  
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} >4#)r8;dx  
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/* `8AR_7i  
**SiteInfoBean.java hp#W9@NR  
*/ %k;|\%B`  
package NetFox; (Tn- >).AO  
0w)^)  
l:j4Ft 8  
public class SiteInfoBean { N'^&\@)xiU  
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U.DDaT1  
private String sSiteURL; //Site's URL M%ICdIc'  
private String sFilePath; //Saved File's Path 6^eV"&+@  
private String sFileName; //Saved File's Name I aGq]z  
private int nSplitter; //Count of Splited Downloading File LIcM3_.  
lu<xv  
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public SiteInfoBean() q35f&O;  
{//nSplitter的缺省值为5 7]b
lrN]  
//default value of nSplitter is 5 4)A#2  
this("","","",5); ,Wk?I%>  
} ]j`c]
2EuP  
~:Ll&29i  
SKkUU^\#R`  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) j`~Ms>  
{ kQEy#JQmB  
sSiteURL= sURL; tasUZ#\6  
sFilePath = sPath; BW 4%l  
sFileName = sName; 9{ >Ui  
this.nSplitter = nSpiltter; .P[ _<8  
Cj{1H([-  
}+C2
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} KY51rw.  
:
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xa<UM5eI  
public String getSSiteURL() n)^i/ nXb'  
{ uI1
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return sSiteURL; XCU7xi$d  
} "|qqUKJZ  
orWbU UC  
;[M}MFc/`  
public void setSSiteURL(String value) 7Rd'm'l)  
{ {bJ`~b9e  
sSiteURL = value; 4nh>'v%pD  
} >`A9[`$n  
n:yTeZ=-s4  
;c4gv,q@  
public String getSFilePath() &Low/Y'.jJ  
{ KG|n  
return sFilePath; }a/x._[s  
} J&.{7YF  
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xI($Uu}S  
public void setSFilePath(String value) /5Oa,NS7  
{ 1*9U1\z  
sFilePath = value; ki?S~'a  
} d$ x"/A]<  
gm igsXQ  
g
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public String getSFileName() ZWc]$H?  
{ ykV 5  
return sFileName; 05b_)&4R  
} 57umx`m  
jRJn+  
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public void setSFileName(String value) CGY]r.O*  
{ -f%'  
sFileName = value; q*_/to  
}  %oZ6l*  

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glM$R&/  
public int getNSplitter() 7UVzp v  
{ s$Z _48  
return nSplitter; l49*<nkmq  
} .Le?T&_  
WtG~('g>&  
@+Si?8\  
public void setNSplitter(int nCount) BJM.iXU)[  
{ `*_mP<Ag  
nSplitter = nCount; [lWQ'DZ  
} lDYyqG4  
} VF?<{F  
[RLN;(0n  
=5/9%P8j9  
/* 8<8:+M}  
**Utility.java pTPi@SBaP{  
*/ lI*o@wQg  
package NetFox; = \'}g?  
n `&/D  
:N4t49i  
public class Utility { Z4S!NDMm~  
~<_2WQ/$  
*h!28Ya(~  
public Utility() W6?pswQ  
{ v"b+$*  
}1Gv)l7  
1*'HL#  
} *>|gxM8  
@D{KdyW  
//线程睡眠 o
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public static void sleep(int nSecond) g!lWu[d  
{ $Tu61zq  
try{ iV'k}rXC  
Thread.sleep(nSecond); N/%WsQp  
} /178A;Jy  
catch(Exception e) H*ow\ Ct  
{ 'p>Ra/4  
e.printStackTrace (); mZSD(  
} _jLL_GD  
} o]yl;I  
QZ6D7tUc8  
//日志 pR(jglm7-  
public static void log(String sMsg) NidIVbT.A  
{ v|uAzM{73  
System.err.println(sMsg); tnH2sHby  
} "e.jZcN*  
7 n8"/0kc:  
fI&t]  
public static void log(int sMsg) U>]$a71  
{ _I@9HC 4  
System.err.println(sMsg); Fv~20G(O  
} <0b)YJb4M  
} c~z82iXNO  
l`oZ)?ur  
)bS yB29S  
/* ~Sj9GxTe  
**TestMethod.java sDPs G5q<  
*/ |TS>hwkI  
package NetFox; '[AlhBX  
w>pq+og&  
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public class TestMethod { `uOT+B%R  
\MyLc/Gh5  
11o.c;  
public TestMethod() vdAr|4^qB  
{ ///xx/weblogic60b2_win.exe #|L8tuWW  
try{ +R3k-' >  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 39:bzUIF  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); >V-A;S:  
SiteFileFetch fileFetch = new SiteFileFetch(bean); [@VP?74  
fileFetch.start(); */sS`/Lx  
} ojcA<60 '  
catch(Exception e){e.printStackTrace ();} 8aK)#tNWN  
eD,.~Y#?=  
 _zY#U9  
} &dqLP95  
C _'%NlJ'  
.+PI}[g  
public static void main(String[] args) &S~zNl^m  
{ z* ^_)Z  
new TestMethod(); tr<Nm6!  
} Hx"ob_^'7  
} nV"~-On  
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