http断点续传简单实现（java)

/* tK3$,9+  
**SiteFileFetch.java 2+&;jgBP  
*/ BZ?w}%-MO  
package NetFox; [j6]!p]S$  
import java.io.*; 2XR!2_)O5  
import java.net.*; 2 5~Z%_?  
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public class SiteFileFetch extends Thread { JG;}UuHYM  
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SiteInfoBean siteInfoBean = null; //文件信息Bean "09v
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long[] nStartPos; //开始位置 "]eB2k_>  
long[] nEndPos; //结束位置 ja9u?UbW  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Mi.#x_  
long nFileLength; //文件长度 dk7x<$h-h0  
boolean bFirst = true; //是否第一次取文件 v~OMm\  
boolean bStop = false; //停止标志 o(tJc}Mh+(  
File tmpFile; //文件下载的临时信息 ,1I-%6L  
DataOutputStream output; //输出到文件的输出流 vAM1|,U  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 9wx]xg4l"  
public SiteFileFetch(SiteInfoBean bean) throws IOException &<><4MQ  
{ 6$OmOCA%  
siteInfoBean = bean; {J"]tx9 ]  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); V?OTP&+J%  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); GbLHzw  
if(tmpFile.exists ()) {`):X_$T  
{ "`;-5dg  
bFirst = false; XVNJK-B  
read_nPos(); (&.T  
} m^FKE:  
else %oqKpD+  
{ E,d<F{=8,o  
nStartPos = new long[bean.getNSplitter()]; GG%;~4#2  
nEndPos = new long[bean.getNSplitter()]; 8Y-*rpLy  
} e;v"d!H/  
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} sSh." H  
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public void run() KC"S06  
{ B.=n U  
//获得文件长度 Zb_A(mnzh  
//分割文件 T 9`AL  
//实例FileSplitterFetch J<L\IP?%  
//启动FileSplitterFetch线程 K bQXH!J  
//等待子线程返回 u3Z]!l
 
try{ r?u4[ Oe#  
if(bFirst) Qq6'[Od  
{ 0e&&k  
nFileLength = getFileSize(); X> 98`  
if(nFileLength == -1) >!qtue7B  
{ aoz+Th3  
System.err.println("File Length is not known!"); [*u\S  
} :ek^M
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else if(nFileLength == -2) 6|lsG6uf  
{ |11vm
#  
System.err.println("File is not access!"); 9_
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}
!
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else ^O<v'\!z-  
{ ;ZuHv {=  
for(int i=0;i<nStartPos.length;i++) 'DXT7|Df  
{ 3f$n8>mq  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); KaMg[G  
} J0vQqTaT  
for(int i=0;i<nEndPos.length-1;i++) rRe^7xGe7  
{ sMAj?]hI$  
nEndPos = nStartPos[i+1]; 4S*ifl  
} /JRZ?/<1  
nEndPos[nEndPos.length-1] = nFileLength; vCej( ))  
} DZmVm['l  
} G1
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//启动子线程 @C^x&Sjm  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 66-\}8f8a  
for(int i=0;i<nStartPos.length;i++) #-Mr3  
{ *jQ$\|Y  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), [(g2u@  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),
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nStartPos,nEndPos,i); Uc_}="  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); (Z @dz  
fileSplitterFetch.start(); i`f!)1  
} Fs~*-R$  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), .fqy[qrM  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); lvODhoT  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", LUxDP#~7  
nEndPos = " + nFileLength); BUwL?  
// fileSplitterFetch[nPos.length-1].start(); i,"Xw[H*s  
huA?*fat   
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//等待子线程结束 ~9APc{"A  
//int count = 0; ?fP3R':s  
//是否结束while循环 <sm"3qs"_  
boolean breakWhile = false; CG@Fn\J  
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while(!bStop) bh5P98s  
{ raOu
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write_nPos(); f?^-JZ  
Utility.sleep(500); :zo5`[P  
breakWhile = true; &`s{-<t<L  
2!}F+^8'P  
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for(int i=0;i<nStartPos.length;i++) " wT?$E  
{ ^S;{;c+'  
if(!fileSplitterFetch.bDownOver) !^y;|9?O  
{ p),*4@2<  
breakWhile = false; _kRc"MaB  
break; FXY>o>K%h  
} gCsN\z  
} OESKLjFt  
if(breakWhile) `WCL-OoZc5  
break; F4-rPv  
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//count++; kmTYRl )j  
//if(count>4) tboQn~&4  
// siteStop(); -,;woOG  
} IEm~^D#<=  
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System.err.println("文件下载结束！"); QPLWRZu@  
} -Wmb M]Z  
catch(Exception e){e.printStackTrace ();} vOCaru?~h  
} @$5~`?  
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//获得文件长度 =$bF[3D  
public long getFileSize() CDtL.a\  
{ 2.Ww(`swL  
int nFileLength = -1; |[5;dt_U/  
try{ YR~e_cA:  
URL url = new URL(siteInfoBean.getSSiteURL()); 8;"%x|iBoL  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); vvY?8/  
httpConnection.setRequestProperty("User-Agent","NetFox"); w0nbL^f  
/@ g 8MUq7  
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int responseCode=httpConnection.getResponseCode(); OSUiS`k  
if(responseCode>=400) bp?TO]LH  
{ 0&|M/  
processErrorCode(responseCode); _8K8Ai-~.>  
return -2; //-2 represent access is error A0A|cJP
 
} lU=VCuW!  
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String sHeader; 2P'Vp7f6 Y  
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for(int i=1;;i++) 7=X6_AD  
{ Cb<7?),vK  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); MW+DqT.h  
//Utility.log(in.readLine()); hmLI9TUe6  
sHeader=httpConnection.getHeaderFieldKey(i); )$f?v22  
if(sHeader!=null) kzUj)  
{ $,r%@'=&  
if(sHeader.equals("Content-Length")) "#0P
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{ +ru`Zw5,  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); =z9,=rR4  
break; ./7-[d  
} }0H<G0  
} B/lIn'=  
else D1>*ml  
break; fM]nP4K`  
} x%@M*4
:&  
} 2w1Mf<IXPo  
catch(IOException e){e.printStackTrace ();} b9i_\  
catch(Exception e){e.printStackTrace ();} g]44|9x(W  
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Utility.log(nFileLength); AZNo%!)o  
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return nFileLength; `'r]Oe  
} SV ~QH&0'  
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//保存下载信息（文件指针位置） Z(4/;v <CT  
private void write_nPos() ;{iTSsb  
{ (qc<'$o  
try{ P*?2+.  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 5)k/4l '  
output.writeInt(nStartPos.length); j/T@-7^0  
for(int i=0;i<nStartPos.length;i++) *CF80
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{ UDcr5u eKn  
// output.writeLong(nPos); 3~WI3ZIR  
output.writeLong(fileSplitterFetch.nStartPos); Eqny'44  
output.writeLong(fileSplitterFetch.nEndPos); w\Q(wH'  
} MB>4Y]rtU  
output.close(); F!C<^q~!  
} r_'];  
catch(IOException e){e.printStackTrace ();} ~k 6V?z}  
catch(Exception e){e.printStackTrace ();} sKiy
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} qIzv|Nte  
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//读取保存的下载信息（文件指针位置） _Eq,udCso  
private void read_nPos() 1)N#  
{ e*D,2>o  
try{ Opy{i#>  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 5?j#  
int nCount = input.readInt(); iY sQ:3s  
nStartPos = new long[nCount]; mSFA i  
nEndPos = new long[nCount]; 3<a|_(K  
for(int i=0;i<nStartPos.length;i++) pF~aR]Q  
{ $Zrc-tkV  
nStartPos = input.readLong(); 
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nEndPos = input.readLong(); /b4>0DXT5  
} PP_ar{|7  
input.close(); `v/p4/  
} eVbT<9k  
catch(IOException e){e.printStackTrace ();} /(s N@kt  
catch(Exception e){e.printStackTrace ();} O6q5qA  
} ?FZ) LZM  
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private void processErrorCode(int nErrorCode) -7I%^u  
{ #V[Os!ns  
System.err.println("Error Code : " + nErrorCode); shY8h   
} mLHl]xs4  
(I1^nrDP.  
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//停止文件下载 '?mky,:HT  
public void siteStop() ZtI@$ An  
{ Nfl5tI$U:  
bStop = true; &_]bzTok  
for(int i=0;i<nStartPos.length;i++) u$"Ew^C  
fileSplitterFetch.splitterStop(); ZzT"u1,&  
9.Sv"=5gz  
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} /EVXkf0  
} JWxSN9.X  
//负责部分文件的抓取 }%,LV]rGEZ  
**FileSplitterFetch.java #\LYo{op/.  
*/ - l0X]&Ex  
package NetFox; <
+<,$jGC-  
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import java.io.*; gYw=Z_z  
import java.net.*; 5%fR9?)  
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public class FileSplitterFetch extends Thread { h7}P5z0F  
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String sURL; //File URL jXyK[q&O&  
long nStartPos; //File Snippet Start Position *nY$YwHB  
long nEndPos; //File Snippet End Position Ec!R3+  
int nThreadID; //Thread's ID MBFn s/  
boolean bDownOver = false; //Downing is over Ehtb`Ms  
boolean bStop = false; //Stop identical t)l^$j!h@  
FileAccessI fileAccessI = null; //File Access interface };~I#X  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException u< 5{H='6  
{ ztaSIMZ  
this.sURL = sURL; Q~)A fa{  
this.nStartPos = nStart; $w! v  
this.nEndPos = nEnd; ']>/$[!  
nThreadID = id; 5S%#3YHY2  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ju/#V}N  
} b5UIX Kim  
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public void run() 24d{ol)  
{ >m`<AynJ  
while(nStartPos < nEndPos && !bStop) 8G_KbS  
{ A}0u-W  
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try{ ,) 3Eog\-  
URL url = new URL(sURL); Wg=4`&F^  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); YR0.m%U,  
httpConnection.setRequestProperty("User-Agent","NetFox"); Vg1MA  
String sProperty = "bytes="+nStartPos+"-"; G/_9!lE  
httpConnection.setRequestProperty("RANGE",sProperty); XbW 1`PH  
Utility.log(sProperty); .^!uazPE0  
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InputStream input = httpConnection.getInputStream(); Hu7WU;w  
//logResponseHead(httpConnection); sFonc  
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byte[] b = new byte[1024]; @"B
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int nRead; |Ht~o(]&&/  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ]*pro|  
{ q `^5<  
nStartPos += fileAccessI.write(b,0,nRead); 6^hCW`jG  
//if(nThreadID == 1) a3E.rr;b  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); U jB5Xks  
} >$N ?\\#  
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Utility.log("Thread " + nThreadID + " is over!"); pwr]lV$w  
bDownOver = true; +p_>fO  
//nPos = fileAccessI.write (b,0,nRead); 'jd fUB  
} =F90SyzTy  
catch(Exception e){e.printStackTrace ();} g.eMGwonTJ  
} }#QYZ nR  
} Lsz)\yIPj  
.V\:)\<|  
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//打印回应的头信息 QB#rf='  
public void logResponseHead(HttpURLConnection con) C:<TJ  
{ K._* ~-A  
for(int i=1;;i++) 2sNV09id  
{ _t;Mi/\P  
String header=con.getHeaderFieldKey(i); 04QY x}a  
if(header!=null) Y8%*S%yO  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); rQ287y{  
Utility.log(header+" : "+con.getHeaderField(header)); Y@R9+7!  
else |GnqfD  
break; %LeZd}v  
} 8+OcM ;0  
} k<!xOg  
/yO|Q{C}M8  
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public void splitterStop() QPT%CW61M  
{ Ym/y2B(  
bStop = true; {/PiX1mn  
}  VqK/GWg  
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} c6f[^Q%#j  
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/* sDzlNMr?P+  
**FileAccess.java bf1EMai"  
*//文件访问(定位，写) %_%/ym  
package NetFox; %+e% RZ3  
import java.io.*; Z/w "zCd  
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S,%BhQ[  
public class FileAccessI implements Serializable{ Ec;{N  
[[;vZ  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 i#W0  
RandomAccessFile oSavedFile; Dhy@!EOS  
long nPos; EAi!"NJ  
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public FileAccessI() throws IOException {#X]D~;s+  
{ Y] "_}  
this("",0); OD\F*Ry~  
} &]mZp&  
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public FileAccessI(String sName,long nPos) throws IOException <qpDAz4k  
{ g<&n V>wF  
oSavedFile = new RandomAccessFile(sName,"rw"); vsL)E:0  
this.nPos = nPos; G(6MLh1  
oSavedFile.seek(nPos); C/L+gU&  
} Yf=Puy}q  
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public synchronized int write(byte[] b,int nStart,int nLen) sq~9 l|F  
{ mqFo`Ee  
int n = -1; G^Q8B^Lg  
try{ rbw5.NU  
oSavedFile.write(b,nStart,nLen); V<%eWT)x7C  
n = nLen; |JD"iP:  
} ;5(ptXX1W  
catch(IOException e) sS5:5i  
{ m5/d=k0l  
e.printStackTrace (); C%l+<wpXO  
} R&`; C<6}D  
8r46Wr7Q  
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return n; +4Uxq{.K  
} [G/ti&Od^  
:g`j gn0  
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} m\hzQ9  
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/* n8dJ6"L<"  
**SiteInfoBean.java R rtr\a  
*/ qP}187Q
1  
package NetFox; sD!)=t_  
7|/Ct
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vTdJe  
public class SiteInfoBean { g$N/pg2>cT  
8wXnc%  
sG6ts,={  
private String sSiteURL; //Site's URL :47bf<w|Y  
private String sFilePath; //Saved File's Path Zr%,F[j?  
private String sFileName; //Saved File's Name +6$|No  
private int nSplitter; //Count of Splited Downloading File ?b8 :  
7l~d_<h  
h'tb  
public SiteInfoBean() abW[hp  
{//nSplitter的缺省值为5 Gz,?e]ZV  
//default value of nSplitter is 5 pp2,d`01[L  
this("","","",5); 0S%xm'|N  
} M:9 6QM~  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) oE
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{ T|%pvTIe  
sSiteURL= sURL; 5C|Y-G  
sFilePath = sPath; fVXZfq6  
sFileName = sName; E<~Fi.M;\  
this.nSplitter = nSpiltter; /~O>He  
,DZoE~  
OABMIgX  
} j+9;Cp]NV  
\{8?HjJEM  
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public String getSSiteURL() zarxv| }$  
{ 5p}ri,Y<  
return sSiteURL; c&mLK1A6  
} <y}9Twdy  
jGSY$nt9  
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public void setSSiteURL(String value) zFba("E Z  
{ RXD*;B$v  
sSiteURL = value; c;13V(Djy  
} :Rftn6!  
(^@rr[.o7  
[qL{w&R  
public String getSFilePath() u{'|/g&  
{ .DX-biX,  
return sFilePath; JH|]B|3  
} zJ $&`=  
1o8C4?T&  
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public void setSFilePath(String value) F<+!28&h  
{ z8@[]6cW  
sFilePath = value; Img$D*BM  
} hE;|VSdo  
l"rX'g?  
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public String getSFileName() JE*d-  
{ ;xl0J*r  
return sFileName; PU2^4h/[`  
} _yRD*2 !;  
;Zy[2M  
lS96Z3k"SB  
public void setSFileName(String value) }WV}in0
 
{ YZk.{#^c  
sFileName = value; (UB?UJ
c  
} FX1H2N(  
dJjkH6%}  
&e6!/y&  
public int getNSplitter() 3OB=D{$V  
{ q"e]\Tb=we  
return nSplitter; b]b+PK*h  
} |JLXgwML  
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bP Q=88*  
public void setNSplitter(int nCount) M5kw3Jy5  
{ we/sv9v}n  
nSplitter = nCount; )`BKEaf  
} yu>o7ie+;Y  
} 4D}hYk$eP0  
)~0TGy|  
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/* EeR}34  
**Utility.java t$e'[;w  
*/ GO)5R,  
package NetFox; !(HPx@_  
b
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ek"Uq RY  
public class Utility { 4a=QTq0p  
.b?Aq^i8  
2FcNzAaV  
public Utility() `W:z#uNG]  
{ +BVY9U?\"  
TM5 Y(Q*  
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} 2){O&8
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<aLS4  
//线程睡眠 O6ph_$nt.  
public static void sleep(int nSecond) .e5d#gE0  
{ UqD ]@s`  
try{ 4T-"\tmg/  
Thread.sleep(nSecond); nV`U{}x  
} BwkY;Ur/AL  
catch(Exception e) N%?R(  
{ |BUgsE  
e.printStackTrace (); :(\JY?+w  
} = N;5T  
} 84!Hd.H  
F{4v[WP)  
//日志 58d[>0Xa[g  
public static void log(String sMsg) 1F_$[iIX]  
{ H,c`=Ii3  
System.err.println(sMsg); `^] D;RfE  
} B 6z 'Q  
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*7E#=xb  
public static void log(int sMsg) Y]7503J  
{ d@p#{ -  
System.err.println(sMsg); 2]<.m]  
} L9<\vJ
 
} 1BEs> Sm  
`yP`
5a/  
+TyN;e  
/* #N"u 0  
**TestMethod.java jo^c>ur  
*/ T9I$6HAi  
package NetFox; yIcTc  
-r_,
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7nPcm;Er  
public class TestMethod { %ioVNbrR7  
d!UxFY@  
j!w{  
public TestMethod() uorX;yekC  
{ ///xx/weblogic60b2_win.exe _3:%b6&Pz  
try{ 6UqAs<
c9  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Av?R6  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); !:m.-TE  
SiteFileFetch fileFetch = new SiteFileFetch(bean); .>eRX%  
fileFetch.start(); hHhDs>tB  
} EG`6T  
catch(Exception e){e.printStackTrace ();} 2QRO$NieV  
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tsJR:~  
} -iS^VzI|I  
eb}P/  
-2; 6Pwmv  
public static void main(String[] args) 9OV@z6
  
{ W} i6{Vh  
new TestMethod(); L2,2Sn*4i  
} e`s1z|h  
} 4`,7tj  
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