http断点续传简单实现（java)

/* QD>"]ap,o  
**SiteFileFetch.java =>! Y{: y(  
*/ q+vx_4  
package NetFox; d:U9pC$  
import java.io.*; B[4KX  
import java.net.*; mFZ?hOyP.  
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6 M*O{f
 
public class SiteFileFetch extends Thread { 4zo5}L`Y  
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SiteInfoBean siteInfoBean = null; //文件信息Bean \9g+^vQ
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long[] nStartPos; //开始位置 !f+H,]D"  
long[] nEndPos; //结束位置 e;[F\ov%  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 "UJ S5[7$  
long nFileLength; //文件长度 ixT:)|'i  
boolean bFirst = true; //是否第一次取文件 CLJ;<  
boolean bStop = false; //停止标志 W!>.$4Q9  
File tmpFile; //文件下载的临时信息 rq/I` :  
DataOutputStream output; //输出到文件的输出流 2mGaD\?K  
]f({`&K5  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） b8LLr;oQw  
public SiteFileFetch(SiteInfoBean bean) throws IOException (X3Tav  
{ hs$GN
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siteInfoBean = bean; +lMX{es\O  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); @("a.;1#o  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ;kJu$U  
if(tmpFile.exists ()) hG_?8:W8HT  
{ N|Sf=q?Ko  
bFirst = false; Go&D[#
 
read_nPos(); 033T>qY  
} +~ #U7xgq/  
else `+/H
^  
{ u?[ q=0.J7  
nStartPos = new long[bean.getNSplitter()]; \@;\t7~  
nEndPos = new long[bean.getNSplitter()]; ~kCwJ<E  
} }BmS)Jq  
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} G8IY#  
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public void run() =]>NDWqpHN  
{ =ORf%f5"'  
//获得文件长度 XIWm>IQ[)  
//分割文件 c:l]=O   
//实例FileSplitterFetch I=O
y-  
//启动FileSplitterFetch线程 ^MmC$U^n  
//等待子线程返回 4{qB X?  
try{ T|"7sPgGR  
if(bFirst) xc?}TPpt  
{ s(_+!d6  
nFileLength = getFileSize(); w^1Fi8+  
if(nFileLength == -1) X[W]=yJJ  
{ IOK}+C0e  
System.err.println("File Length is not known!"); p[2GkP  
} kHJ96G  
else if(nFileLength == -2) M3z
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{ lr2rQo>  
System.err.println("File is not access!"); s^T+5E&}  
} zEw>SP1,  
else 4UA
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{ E-1"+p  
for(int i=0;i<nStartPos.length;i++) .~}z4r  
{ T[Pa/j{  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Z v0C@r  
} <3hA!$o~  
for(int i=0;i<nEndPos.length-1;i++) FXo2Y]K3`L  
{ Vj; vo`T  
nEndPos = nStartPos[i+1]; ~k'V*ERNSj  
} :
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nEndPos[nEndPos.length-1] = nFileLength; |)W!jC&k  
} W>spz~w%j  
} !ax;5@J  
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g$j6n{Yl  
//启动子线程 A2x;fgi  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; #Nte^
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for(int i=0;i<nStartPos.length;i++) rdj@u47  
{ j.3o W  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), wAbp3hX  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), H]&!'\aUz  
nStartPos,nEndPos,i); GoE#Mxhxo  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); dyQh:u -  
fileSplitterFetch.start(); FQf#*  
} U |F>W~%  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), b2h":G|s  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); H?}wl%  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Nm8w/Q5D`  
nEndPos = " + nFileLength); =8{*@>CX  
// fileSplitterFetch[nPos.length-1].start(); ~SVQ;U)-  
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//等待子线程结束 <<3+g"enno  
//int count = 0; W._G0b4}  
//是否结束while循环 7;HUE!5,^l  
boolean breakWhile = false; p[YWSjf  
(Cj,\r  
5_G'68;OV  
while(!bStop) s!h5hwBY  
{ dE>v\0 3!8  
write_nPos(); X*D5y8<  
Utility.sleep(500); 9;'>\ImI  
breakWhile = true; +K @J*W 1  
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for(int i=0;i<nStartPos.length;i++) R;N>#_9HU  
{ KG7X8AaK#  
if(!fileSplitterFetch.bDownOver) CgaB)`.  
{ (W{rv6cq  
breakWhile = false; ]ys4  
break; UwzE'#Q-  
} 'R-JQE-]  
} ACMpm~C8Gu  
if(breakWhile) g@N=N  
break; a93d'ZE-X  
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8
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//count++; l)2HHu<  
//if(count>4) cfQh  
// siteStop(); *
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} Vf\?^h(tP  
)x5$io   
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System.err.println("文件下载结束！"); t8wz'[z  
} OM#OPB rB  
catch(Exception e){e.printStackTrace ();} 1&>nL`E[3  
} E|6Z]6[  
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//获得文件长度 Dk.9&9mz  
public long getFileSize() jd*%.FDi{  
{ PSrt/y!  
int nFileLength = -1; &t=>:C$1Y  
try{ N!4xP.Ps  
URL url = new URL(siteInfoBean.getSSiteURL()); K:Xrfn{s  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); `Mh<S+/  
httpConnection.setRequestProperty("User-Agent","NetFox"); c`N`xU+z  
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7;#dX~>@{  
int responseCode=httpConnection.getResponseCode(); v
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if(responseCode>=400) qjRiTIp9q  
{ ![."xHVeL  
processErrorCode(responseCode); =Q8^@i4[&D  
return -2; //-2 represent access is error 9gIJX?  
} QW"6]  

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String sHeader; u=UM^C!
 
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for(int i=1;;i++) <raqp Oo&  
{ Exo`Z`m`U  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 2b&
;Y/z  
//Utility.log(in.readLine()); '9F{.]  
sHeader=httpConnection.getHeaderFieldKey(i); 06W=(fY  
if(sHeader!=null) qt&"cw  
{ |&pz,"(  
if(sHeader.equals("Content-Length")) y:``|*+  
{ p<nBS"/  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); r.G/f{=<@  
break; })u}PQ  
} m ?tnk?oX  
} _q 9lr8hx  
else ,,j=RG_  
break; T_B.p*\BM  
} ?g*T3S"  
} 8gKR<X.G  
catch(IOException e){e.printStackTrace ();} t>`LO  
catch(Exception e){e.printStackTrace ();} Jn[ K0GV  
9@EnmtR  
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Utility.log(nFileLength); h swMy  
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return nFileLength; Wjk;"_"gd  
} fQA)r  
={0{X9t?'j  
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-  
//保存下载信息（文件指针位置） PC7.+;1  
private void write_nPos() \ozy_s[  
{ .W.U:C1  
try{ M!XFb  
output = new DataOutputStream(new FileOutputStream(tmpFile)); K}(n;6\  
output.writeInt(nStartPos.length); ~\IDg/9Cj  
for(int i=0;i<nStartPos.length;i++) toZI.cSg4  
{ q5?mP6
 
// output.writeLong(nPos); &rWJg6/  
output.writeLong(fileSplitterFetch.nStartPos); TB[2!ZW  
output.writeLong(fileSplitterFetch.nEndPos); s;f u  
} 9)hC,)5  
output.close(); IL"#TKKv  
} }4MG114j  
catch(IOException e){e.printStackTrace ();} zO]dQ$r\Z  
catch(Exception e){e.printStackTrace ();} 7B2Og{P  
} g%P4$|C9i  
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//读取保存的下载信息（文件指针位置） sjkl? _  
private void read_nPos() e|9Bzli{  
{ Rp9iX~A`e  
try{ PS]XLz  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); U}Fk%Jj  
int nCount = input.readInt(); yYtki  
nStartPos = new long[nCount]; V$D d 7  
nEndPos = new long[nCount]; =#fvdj  
for(int i=0;i<nStartPos.length;i++) "t`e68{Ls  
{ .lS6KBf@  
nStartPos = input.readLong(); VO/" ot  
nEndPos = input.readLong(); kce+aiv|u  
} ~g~z"!K  
input.close(); \HV%579  
} /DJyNf*  
catch(IOException e){e.printStackTrace ();} S_ e }>-  
catch(Exception e){e.printStackTrace ();} LH3PgGi,  
} j ]F  Zy  
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private void processErrorCode(int nErrorCode) 5!N
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{ J}nE,U
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System.err.println("Error Code : " + nErrorCode); r,EIOcz:  
} VD<W  
t%/Y^N;  
wBA[L}   
//停止文件下载 W,}HQ  
public void siteStop() \:'=ccf  
{ y8D'V)B
  
bStop = true; *U)!9DvA  
for(int i=0;i<nStartPos.length;i++) =ugxPgn  
fileSplitterFetch.splitterStop(); "
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} ezY _7  
} !dv  
//负责部分文件的抓取 mh2t ' O  
**FileSplitterFetch.java ,9`sC8w|  
*/ >u4%s7v  
package NetFox; {]n5h#c 5*  
"Rf8#\Y/<  
tT ~}lW)Y  
import java.io.*; Mp:tcy,*  
import java.net.*; 
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public class FileSplitterFetch extends Thread { k+f!)7_  
Q?B5@J  
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String sURL; //File URL  !NUsfd  
long nStartPos; //File Snippet Start Position Em N0K'x  
long nEndPos; //File Snippet End Position )Fe-C  
int nThreadID; //Thread's ID qrsPY d  
boolean bDownOver = false; //Downing is over G9TK)Nz  
boolean bStop = false; //Stop identical R%Gh4y\nF  
FileAccessI fileAccessI = null; //File Access interface 0C#1/o)o  
5P9hm[  
z
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException kL 6f^MoL  
{ k6_RJ8I  
this.sURL = sURL; 0K <@?cI  
this.nStartPos = nStart; C\Qor3];  
this.nEndPos = nEnd; vz</|s  
nThreadID = id; 8l-+ 4~mH  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 oj /:  
} *A':^vgk  
()6)|A<^U  
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public void run() (9]`3^_,J  
{ WHk/Rg%<  
while(nStartPos < nEndPos && !bStop) (.-3q;)6  
{ uvz}qH@j/Q  
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try{ "FhC"}N  
URL url = new URL(sURL); x!vyjp  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); C9!FnvH
 
httpConnection.setRequestProperty("User-Agent","NetFox"); SS24@:"{  
String sProperty = "bytes="+nStartPos+"-"; MX?UmQ'  
httpConnection.setRequestProperty("RANGE",sProperty); =tY%`e  
Utility.log(sProperty); mdQe)>  
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InputStream input = httpConnection.getInputStream(); :-lq Yd5^  
//logResponseHead(httpConnection); ~l?c.CSd  
7E#h(bt j  
:Ny[?jtc  
byte[] b = new byte[1024]; UZmUYSu;  
int nRead; 63_#*6Pv28  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) p&u\gSo  
{ `HnZ{PKf  
nStartPos += fileAccessI.write(b,0,nRead); 0v9i43[S|J  
//if(nThreadID == 1) e=p_qhBt  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 9Iq<*\V 4  
} ZMr[:,Jp  
n7Bv~?DM  
$T:;KcW)  
Utility.log("Thread " + nThreadID + " is over!"); zY@0R`{@p  
bDownOver = true; I$x<B7U  
//nPos = fileAccessI.write (b,0,nRead); +-SO}P  
} bA2[=6  
catch(Exception e){e.printStackTrace ();} w|6?A-  
} ;&f(7 Q+T_  
} iPY)Ew`Im  
lq]8zm<\)]  
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//打印回应的头信息 ` ~^My~f  
public void logResponseHead(HttpURLConnection con)
w8
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{ P*>?/I`G  
for(int i=1;;i++) ~`^kP.()  
{ W"pHR sf  
String header=con.getHeaderFieldKey(i); ]q4LNo  
if(header!=null) R.l
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//responseHeaders.put(header,httpConnection.getHeaderField(header)); &iq'V*+-\  
Utility.log(header+" : "+con.getHeaderField(header)); AS:k&t  
else !};Ll=dz  
break; lKU{jWA  
} }.U(Gxu$  
} mA%}ijR6y  
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{~R?f$}""j  
public void splitterStop() GUM-|[~  
{ xXI WEZA  
bStop = true; fk6=;{  
} .xp|w^  
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} Z/ypWoV(  
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/* ?)~j>1"S  
**FileAccess.java
Kc:} Ky  
*//文件访问(定位，写) I2wT]L UV  
package NetFox; E0i_sB~T  
import java.io.*; >xt*(j&}  
fii\&p7z  
:
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public class FileAccessI implements Serializable{ '0xJp|[xVP  
UT9=S21  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 9$xEktfV  
RandomAccessFile oSavedFile; j8G>0f)  
long nPos; V!SB9t`E  
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public FileAccessI() throws IOException 3\,TI`^C  
{ QsmG(1=  
this("",0); wBcDL/(>  
} y(RbW_ ?  
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"gCSbMq(Vq  
public FileAccessI(String sName,long nPos) throws IOException A&5$eGe9  
{ ubhem(p#  
oSavedFile = new RandomAccessFile(sName,"rw");  <C4^Vem  
this.nPos = nPos; %;9eh'  
oSavedFile.seek(nPos); ,gU9ywg  
} U6=m4]~Z  
%a/O7s6  
kmW!0hm;e  
public synchronized int write(byte[] b,int nStart,int nLen) ?<w +{  
{ t:M({|m Y  
int n = -1; _>5BFQ_  
try{ xuelo0h,  
oSavedFile.write(b,nStart,nLen); qc\o>$-:`  
n = nLen; 1&YP}sg)  
} ,)L.^<  
catch(IOException e) [uRsB5  
{ p,D/ Pb8  
e.printStackTrace (); TF^]^XS'  
} xDr *|d  
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return n; l!iB -?'u  
} .yWdlq##  
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. ~|^du<X  
} N=+Up\h
  
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/* w\t{'  
**SiteInfoBean.java |J}~a8o  
*/ E$G"R=  
package NetFox; G#% =R`k/  
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public class SiteInfoBean { 9)YG)A~<  
rWvJ{-%  
Vfw$>og!  
private String sSiteURL; //Site's URL 3]VTQl{P  
private String sFilePath; //Saved File's Path d7G'
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private String sFileName; //Saved File's Name :!A@B.E  
private int nSplitter; //Count of Splited Downloading File $K G?d>wx  
ZK'I$p]b  
X>wQYIi  
public SiteInfoBean() a,tP.Xsl  
{//nSplitter的缺省值为5 L]tyL)  
//default value of nSplitter is 5 o4Ba l^=[  
this("","","",5); p' gv5\u[w  
} HxM-VK'  
!9N%=6\  
QTyl=z7  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Z2@&4_P  
{ [,e_2<  
sSiteURL= sURL; Yp;x  
sFilePath = sPath; `150$*K&B  
sFileName = sName; PRUGUHY  
this.nSplitter = nSpiltter; (C:rH  
oyd{}$71d  
A
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} #QB`'2)vw  
 )Ob{]  
>]`x~cE.5  
public String getSSiteURL() b13>>'BMB  
{ WgL!@
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return sSiteURL; D *tBbV  
} 3A9|{Vaz+6  
YJ0[BcZ  
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public void setSSiteURL(String value) :`|,a(  
{ Ylf4q/-  
sSiteURL = value; .6hH}BM  
} (+@.L7>m+t  
M1i|qjb:l  
oa4}GNH  
public String getSFilePath() -/</7I  
{ BCj&z{5"7e  
return sFilePath; ;CrA  
} Em7q@  
4>W`XH  
4j*}|@x  
public void setSFilePath(String value) )<|TEp4r-  
{ DjKjEZHgM  
sFilePath = value; 6IX!9I\sT  
} `#]\Wnp~y  
p#kC#{<nE  
a !IH-XJ2  
public String getSFileName() YJy*OS_&  
{ r~TT c)2  
return sFileName; EI;\of2,  
} NR*SEbUU*  
A0XFu}  
V~=)#3]`[  
public void setSFileName(String value) W)#`4a^xj7  
{ ~g{,W  
sFileName = value; w.8~A,5}Dh  
} WdT|xf.Q&  
>$y >  
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public int getNSplitter() ZwMw g t  
{ x3Ud0[(  
return nSplitter; nR7\ o(!  
} #-;BU{3*  
]c)SVn$6  
Ps7%:|K]
  
public void setNSplitter(int nCount) IfcFlXmt2  
{ OLrD4 e  
nSplitter = nCount; V%ch'  
} W%1S:2+Kl  
} `y}
d)"!  
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/* Bt,Xe~$z-  
**Utility.java x/=j$oA  
*/ vNC0M:p,  
package NetFox; yr>bL"!CA  
"|%9
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public class Utility { \#aVu^`eX  
^>Y%L(>  
YJ$ewK4E#.  
public Utility() $hSZ@w|IF  
{ %7msAvbk  
86#mmm)  
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} hli10p$  
|lxy< C4V  
//线程睡眠 ?Z>.G{Wm@  
public static void sleep(int nSecond) "Vq]|j,B/c  
{
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try{ W(h8!}  
Thread.sleep(nSecond); }4SSo)Uv/  
} xGfDz*t  
catch(Exception e) JGcD{RU|  
{ vQ"s  
e.printStackTrace (); ~AanU1U<  
} O[)]dD&'  
} eJw
="  
&
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//日志 $-Pqs ^g  
public static void log(String sMsg) _1<'"u#6w  
{ BD7@Mj*|  
System.err.println(sMsg); pXh~#o6V  
} d-;9L56{P  
`E5"Pmg  
rLh9`0|D  
public static void log(int sMsg) X@qk>/  
{ R pI<]1
  
System.err.println(sMsg); s)YP%vn#  
} u:$x6/t  
} 96pk[5lj{?  
kAN;S<jSE  
y[p$/$bgC5  
/* 3z)"U  
**TestMethod.java $54=gRo^  
*/ .S!>9X,  
package NetFox; Q"|kW[Sg  
%gu$_S  
P$18Xno{  
public class TestMethod { :vK(LU0K  
oY%"2PW1B  
')5L_$  
public TestMethod() _t|G@D{   
{ ///xx/weblogic60b2_win.exe e
" Eqi-
 
try{ 8jggc#.  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); wI! +L&Q  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); M_h8#7{G  
SiteFileFetch fileFetch = new SiteFileFetch(bean); VJN/#   
fileFetch.start(); ^p 2.UW  
} 9$o<  
catch(Exception e){e.printStackTrace ();} ]D LZ&5pv  
r+{d!CHq}  
]bTzbu@  
} m']9Q3-  
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public static void main(String[] args) 7`IUM
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{ jq57C}X}2  
new TestMethod(); 4D^ M<Xn  
} #%?FM>  
} Z}8k[*.  
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