http断点续传简单实现（java)

/* 3A\Hiy!{F  
**SiteFileFetch.java Pb@$RAU63  
*/ 1ahb:Mjv  
package NetFox; (t,|FkVLV  
import java.io.*; ?DNeL;6  
import java.net.*; &,]yqG 2  
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y] $-:^  
public class SiteFileFetch extends Thread { ,qdZ6bv,]|  
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SiteInfoBean siteInfoBean = null; //文件信息Bean |l?*' =  
long[] nStartPos; //开始位置 k9&pX8#  
long[] nEndPos; //结束位置 mT1Q7ta*P  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 n{c-3w.uD  
long nFileLength; //文件长度 |B),N f|a  
boolean bFirst = true; //是否第一次取文件 '1\UFz  
boolean bStop = false; //停止标志 f{]W*!VV-  
File tmpFile; //文件下载的临时信息 GMob&0l8_  
DataOutputStream output; //输出到文件的输出流 ~@D!E/
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） Y3'dV)  
public SiteFileFetch(SiteInfoBean bean) throws IOException oYeFOw`  
{ &v+Hl^  
siteInfoBean = bean; cn_*,\}  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); LQ"xm  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); H.2aoZ-w  
if(tmpFile.exists ()) m W4tW  
{ v(jZ[{x@  
bFirst = false; @Z9>E+udQ  
read_nPos(); }iB>3|\  
} Z2k5qs7g  
else ` B+Pl6l)F  
{ TiI3<.a!  
nStartPos = new long[bean.getNSplitter()]; 
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nEndPos = new long[bean.getNSplitter()]; piPV&ytI  
} Jqt|'G3  
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} 7{ QjE  
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public void run() xEe3,tb'e  
{ 5|oi*b  
//获得文件长度 yrrP#F  
//分割文件 ]-u>HO g\  
//实例FileSplitterFetch ]i'gU(+;`  
//启动FileSplitterFetch线程 (_~Dyvo  
//等待子线程返回 "eKM<S  
try{ 5cC)&}I  
if(bFirst) *3!ixDX[r  
{ 3#c0p790  
nFileLength = getFileSize(); t3aDDu  
if(nFileLength == -1) L>2gx$f  
{ 4:XVu
  
System.err.println("File Length is not known!"); j|(bdTZY:  
} `[.4SIah  
else if(nFileLength == -2) G%fNGQwT  
{ Kdb:Q0B  
System.err.println("File is not access!"); ^g N?I
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} _~E_#cNn  
else 0Y ld!L  
{ ltG|#(  
for(int i=0;i<nStartPos.length;i++) k|_LF[*Z  
{ ^9*Jz{e  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ?rububDT{  
} nA XWbavY  
for(int i=0;i<nEndPos.length-1;i++) @?<1~/sfL  
{ 7.1FRxS  
nEndPos = nStartPos[i+1]; ~C;gEE-  
} EcmyY,w  
nEndPos[nEndPos.length-1] = nFileLength; Ezw<  
} Zk 9i}H  
} x?-kt.M  
.&c!k1kH  
@RVj~J.A  
//启动子线程 Pt%Ey
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; BYsQu.N  
for(int i=0;i<nStartPos.length;i++) 6SmawPPP  
{ yDBMm^  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), &GLe4zEh  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), }q[IhjD%  
nStartPos,nEndPos,i); U10:@Wzh  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); H=7Nh6v  
fileSplitterFetch.start(); RB/;qdqR  
} 2o9IP>#u  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), D,;6$Pvg^  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); G_n~1?  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Z"g6z#L&  
nEndPos = " + nFileLength); bjGQ04da  
// fileSplitterFetch[nPos.length-1].start(); 1 gx(L*y,  
{'eF;!!Dy  
]5i]2r1  
//等待子线程结束 (e6KSRh2fF  
//int count = 0; _'DZoOH|VE  
//是否结束while循环 iQ_^MzA  
boolean breakWhile = false; }{m.\O  
g|V0[Hnq6  
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while(!bStop) ( G#W6  
{ ^6I8a"  
write_nPos(); Q?TXM1Bp  
Utility.sleep(500); c,RY j  
breakWhile = true; P0^7hSo  
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for(int i=0;i<nStartPos.length;i++) n!t][d/g+  
{ LuW^Ga"E  
if(!fileSplitterFetch.bDownOver) ,Taq~  
{ ?{*/VJl$  
breakWhile = false; .LHzaeJCX  
break; Y]Y]"y$1  
} rpO>l  
} nfzKUJY  
if(breakWhile) DANndXQLH  
break; 07tSXl5!  
b_j8g{/9  
23=SXA!  
//count++; ZpQ8KY$5  
//if(count>4) /A~+32B  
// siteStop(); LS4|$X4H`!  
} _q dLA  
I &I q  
fE/|U|5L[  
System.err.println("文件下载结束！"); 8NzXe 7  
} U/I+A|S[  
catch(Exception e){e.printStackTrace ();} y153ax  
} qJrMr4:F  
G@;I^_gN  
PFnq:G^L  
//获得文件长度 ;Q} H'Wg,  
public long getFileSize() 4Gm(P~N  
{ N:Zf4  
int nFileLength = -1; gR:21*&cz  
try{ |Zrkk>GW:  
URL url = new URL(siteInfoBean.getSSiteURL()); R~&i8n.  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); -6u#:pVpU  
httpConnection.setRequestProperty("User-Agent","NetFox"); qo"_w%{  
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!~~j&+hK\  
int responseCode=httpConnection.getResponseCode(); gC qQ~lWZ  
if(responseCode>=400) >E3 lY/[  
{ Co#_Cyxg=9  
processErrorCode(responseCode); *=ymK*  
return -2; //-2 represent access is error r@m2foaO  
} 2r|!:^'?W  
wk"zpI7L  
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String sHeader; #XlE_XD  
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for(int i=1;;i++) N>}2&'I  
{ [5Dg%?x  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); *PV
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//Utility.log(in.readLine()); +w pe<T  
sHeader=httpConnection.getHeaderFieldKey(i); dECH/vJ^  
if(sHeader!=null) HGjGV]N5  
{ :'LG%E:b  
if(sHeader.equals("Content-Length")) =wy
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{
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nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); IN%04~=H  
break; `e!hT@Xxa  
} 2dF:;k k  
} /o_h'l|PS  
else b|HH9\  
break; Qe )#'$T  
} axW4cS ?  
} hj.Du+1  
catch(IOException e){e.printStackTrace ();} )tV^)n[w  
catch(Exception e){e.printStackTrace ();} Z|kMoB  
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9  
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Utility.log(nFileLength); $ (gR^L  
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return nFileLength; t[
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} !F|iL  
!B3lsXLSY  
hoQ?8}r:  
//保存下载信息（文件指针位置） c.\J_^  
private void write_nPos() fii\&p7z  
{ -^JGa{9*  
try{ *I}_
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output = new DataOutputStream(new FileOutputStream(tmpFile)); *G{Zo*2< i  
output.writeInt(nStartPos.length); G Riu]   
for(int i=0;i<nStartPos.length;i++) Q4;br?2H  
{ RO"*&o'K'  
// output.writeLong(nPos); HGgw<Os-k  
output.writeLong(fileSplitterFetch.nStartPos); \O7?!i  
output.writeLong(fileSplitterFetch.nEndPos); Tcglt>tj"  
} Ht'jm(  
output.close(); {:3XP<hqN  
} `f2m5qTP%  
catch(IOException e){e.printStackTrace ();} ,j('QvavJ  
catch(Exception e){e.printStackTrace ();} ]PnE%  
} :-f"+v  
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r]=3aebR.  
//读取保存的下载信息（文件指针位置） j{nkus2  
private void read_nPos() Vo%UiVHy  
{ 79^on8k}  
try{ A_t<SG5  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); O;A/(lPW+  
int nCount = input.readInt(); ]rh)AE!Y(  
nStartPos = new long[nCount]; "iof -b=ys  
nEndPos = new long[nCount]; T'*.LpNP,  
for(int i=0;i<nStartPos.length;i++) Z6cG<,DQ  
{
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nStartPos = input.readLong(); (8r?'H8ZO  
nEndPos = input.readLong(); IpxFME%!  
} Q#bFW?>y,  
input.close(); i#jCf3%+ h  
} ^saJfr
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catch(IOException e){e.printStackTrace ();} 5m+:G
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catch(Exception e){e.printStackTrace ();} g"3h#SMb  
} , "zS  pN  
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private void processErrorCode(int nErrorCode) Ej1 [ry  
{ Dz&4za+{  
System.err.println("Error Code : " + nErrorCode); b)u9#%Q  
} d]e`t"Aj  
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)N-+,Ms  
//停止文件下载 UY**3MK  
public void siteStop() na FZ<'t>&  
{ XEZ6%Q_  
bStop = true; $Mx.8FC +  
for(int i=0;i<nStartPos.length;i++) kmW!0hm;e  
fileSplitterFetch.splitterStop(); lb1(1|#  
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} B`hxF(_p/  
} LFSOHJj  
//负责部分文件的抓取 su=.4JcK  
**FileSplitterFetch.java xuelo0h,  
*/ "0L@cOyG  
package NetFox; /]xd[^  
%!rsu-W:Y  
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import java.io.*; Pr<?E[  
import java.net.*; #U/B,`= >  
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public class FileSplitterFetch extends Thread { q@(N 38D  
]?)zH:2)  
PJAir8  
String sURL; //File URL raJyo>xXb5  
long nStartPos; //File Snippet Start Position `T9
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long nEndPos; //File Snippet End Position o7 !@WOeZ3  
int nThreadID; //Thread's ID ,iPkx(  
boolean bDownOver = false; //Downing is over ijhMJ?3  
boolean bStop = false; //Stop identical {/7'uD\ H  
FileAccessI fileAccessI = null; //File Access interface Mdwh-Cis/  
!s)2H/KM8  
>5 5/@+^  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 0/KNXz  
{ iCx'`^H
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this.sURL = sURL; g1J]z<&  
this.nStartPos = nStart; f\(Kou$  
this.nEndPos = nEnd; jv0e&rt  
nThreadID = id; # |UrHK;  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ;U`HvIch  
} 0XozYyq  
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public void run() [=E<iPl  
{ .Yu,&HR  
while(nStartPos < nEndPos && !bStop) d&'6l"${  
{ 50H[u|  
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try{ 98O z  
URL url = new URL(sURL); 1g/mzC
  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Bv=Z*"Fv  
httpConnection.setRequestProperty("User-Agent","NetFox"); alu`T c~  
String sProperty = "bytes="+nStartPos+"-"; /|DQ_<*  
httpConnection.setRequestProperty("RANGE",sProperty); jY?%LY@5I  
Utility.log(sProperty); *smo{!0Gg  
&FanD  
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InputStream input = httpConnection.getInputStream(); lMO0d_:b1  
//logResponseHead(httpConnection); Q'=!1^&  
q5RLIstQ\  
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byte[] b = new byte[1024]; Sdt @"6  
int nRead; ,vhR99g{  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) xjX5PQu  
{ OIWo* %  
nStartPos += fileAccessI.write(b,0,nRead); Ql V:8:H$  
//if(nThreadID == 1) ]CL70+[^9  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); L]tyL)  
} G/`_$ c  
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7PvuKAv?k  
Utility.log("Thread " + nThreadID + " is over!"); [wOO)FjT  
bDownOver = true; O>>8%=5Q  
//nPos = fileAccessI.write (b,0,nRead); yi%B5KF~Al  
} QWP_8$Q  
catch(Exception e){e.printStackTrace ();}
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} 7v:;`6Jb  
} PHOW,8)dZh  
WMC6dD_6e  
4v?S`w:6  
//打印回应的头信息 !kz\ {  
public void logResponseHead(HttpURLConnection con) k4l72 'P  
{ [j/-(?+  
for(int i=1;;i++) (nzzX?`nY  
{ D6m>>&E['  
String header=con.getHeaderFieldKey(i); r:o!w7C:a  
if(header!=null) \4&g5vE  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); oyd{}$71d  
Utility.log(header+" : "+con.getHeaderField(header)); :dj@i6  
else d8K^`k+x  
break; l%:_#1?isf  
} l{3utQH-=z  
} /za,&7sf  
]Lh\[@#1f  
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public void splitterStop() NdZ: 
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{ r9U1O@c  
bStop = true; 9PBmBP~  
} a|>MueJ  
}qg!U
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} >w'6ZDA*X  
n#R!`*[  
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/* Owr`ip\  
**FileAccess.java G@;aqe[dB  
*//文件访问(定位，写) p[$I{F*a  
package NetFox; Z~R i%XG  
import java.io.*; O//e0?]W  
#-`lLI:w0  
g=%&p?1@E  
public class FileAccessI implements Serializable{ *!Dzst-J3  
ubQ(O uM"  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ;CrA  
RandomAccessFile oSavedFile; A4^+p0@  
long nPos; 3m^BYr*y^  
'ZDclz9}  
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public FileAccessI() throws IOException C+mU_g>  
{ f0F$*"#G  
this("",0); kmS8>O  
} )eFK@goGeb  
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s6$3[9Vh&9  
public FileAccessI(String sName,long nPos) throws IOException Y:a(y*y<  
{ oK>,MdB  
oSavedFile = new RandomAccessFile(sName,"rw"); t&xx-4  
this.nPos = nPos; C/bttd  
oSavedFile.seek(nPos); P8jK yo  
} fin15k  
x\%egw  
xv:?n^yt.[  
public synchronized int write(byte[] b,int nStart,int nLen) jBC9Vt;B  
{ A>?fbY2n  
int n = -1; oxzNV&D[{`  
try{ L`#+ZLo  
oSavedFile.write(b,nStart,nLen); kpdFb7>|  
n = nLen; ^WNJQg'  
} A=$oYBB  
catch(IOException e) W)#`4a^xj7  
{ Y!L jy [/  
e.printStackTrace (); ?Z=v&d[o)  
} VC.?]'OqD  
qEAF!iB]L  
-:,h8JyMP  
return n; r>Ln*R,9D  
} I?>#neHc6  
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} q :bKT#\  
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8VZ-`?p  
/* zCHr  
**SiteInfoBean.java x3Ud0[(  
*/
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package NetFox; "YL-!P  
:3B\,inJ  
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public class SiteInfoBean { my1kF%?  
a%dx\&K  
pd#/;LT  
private String sSiteURL; //Site's URL b5DrwX{Ff  
private String sFilePath; //Saved File's Path L,6Y=?  
private String sFileName; //Saved File's Name HhL%iy1  
private int nSplitter; //Count of Splited Downloading File 0U>Q<I}  
FT~^$)8=  
4i,SiFKB  
public SiteInfoBean() Bu1z$#AC  
{//nSplitter的缺省值为5 #lF<="y%X  
//default value of nSplitter is 5 K(gj6SrjV  
this("","","",5); i.sq^]j  
} HhvG
#Sam!  
{<kG{i/  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 8|({ _Z
 
{ MxRU6+a  
sSiteURL= sURL; D@^ZpN8r  
sFilePath = sPath; $T6Qg(p  
sFileName = sName; GcR`{ 3hO  
this.nSplitter = nSpiltter; vgj^-  
9#<Og>t2y  
5-^%\?,x  
} ^%&x{F.  
%K"%Qm=Tl  
Jdn*?hc+  
public String getSSiteURL() d 4]%Wdvf  
{ g5Rm!T+@I<  
return sSiteURL; s{e(- 7'  
} Ug21d42Z4  
$)Yog]}  
 3Mx@  
public void setSSiteURL(String value) hli10p$  
{ %v[Kk-d  
sSiteURL = value; 1v&Fo2ML  
} ?Z>.G{Wm@  
"!tw ,Gp  

6[.Mx}h6  
public String getSFilePath() A+I&.\QAR  
{ J\3} il N  
return sFilePath; #[y<h3f]  
} N}fUBX4k  
,:4DN&<  
t1jlxK  
public void setSFilePath(String value) ht)nx,e=  
{ m>ycN  
sFilePath = value; s&hA  
} S |>$0P4W(  
P/Kit?kngS  
hFMst%:y$  
public String getSFileName() V:BX"$J1  
{ nud=uJ"(  
return sFileName; \oX8/-0f  
} R:<@+z^A[  
_-]!;0EIV  
*W12Rb2  
public void setSFileName(String value) o^Ysp&#p  
{ vQ"s  
sFileName = value; `8;,&<U'`  
} hF"g91P  
QO{=Wi-  
V wVQ|UH  
public int getNSplitter() PgLS\_B  
{ "F$o!Vk  
return nSplitter; [fi'=Cb  
} ShJK&70O  
cEc,e
q|  
F,M"/hnPT  
public void setNSplitter(int nCount) P4j8`}&/  
{ ,6;xr'[o*  
nSplitter = nCount; }b+QYSt  
} #we>75l{+R  
} _]xt65TL  
RR!!hY3 K  
]<T8ZA_Y;  
/* l(,;w
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**Utility.java ;{f??G  
*/ 0^_
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package NetFox; EB5_;  
!?o$-+a|  
2l@"p!ar=  
public class Utility { oD#>8Aws  
kq~[k.  
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public Utility() ,LW+7yD  
{ c5E#QV0&v~  
[OZ=iz.  
rN1U.FRe/
 
} ^8NLe9~p3?  
HCG@#W<wc  
//线程睡眠 B>Cs&}Y!  
public static void sleep(int nSecond) xs'kO=  
{ O R<"LTCL  
try{ Ae j   
Thread.sleep(nSecond); K- I\P6R`  
} D!}K)T1~R  
catch(Exception e) /.)[9bQ<  
{ -~\.n  
e.printStackTrace (); 6f?BltFaN  
} 5m^Hi}S_  
} 4b2mtLn_  
Mf:M3H%YV+  
//日志 pAil]f6  
public static void log(String sMsg) E8-fW\!F  
{ W 9Vz[  
System.err.println(sMsg); 'Z.OF5|eGT  
} aLKMDiT  
v0`qM
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h zZ-$IX X  
public static void log(int sMsg) cc41b*ci$  
{ R6q4 ["  
System.err.println(sMsg); iog # ,  
} 8jggc#.  
} 5, -pBep<  
wI! +L&Q  
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/* M_h8#7{G  
**TestMethod.java hB?,7-  
*/ VJN/#   
package NetFox; O:;OR'N9  
-4e)N*VVu  
9K;k%  
public class TestMethod { 4r1<,{gCS  
NTm<6Is`  
>; &s['H  
public TestMethod() PNbcy!\U  
{ ///xx/weblogic60b2_win.exe #9D/jYK1X  
try{ .QXG"R  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); >'aG/(  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); d$fvg8^  
SiteFileFetch fileFetch = new SiteFileFetch(bean); "($Lx  
fileFetch.start(); 9jO`gWxV8*  
} &_9YLXtMi;  
catch(Exception e){e.printStackTrace ();} 'u(=eJ@1  
VyecTU"W  
C5es2!^-]O  
} "H>r-cyh  
jq57C}X}2  
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public static void main(String[] args) |5=~(-I>@  
{ =
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new TestMethod(); #%?FM>  
} #)^^_  
} ]8$#qDS@  
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