http断点续传简单实现（java)

/* %|R]nB  
**SiteFileFetch.java wF6a*b@v  
*/ #X{lV]Z  
package NetFox; [(8s\>T  
import java.io.*; <5FGL96  
import java.net.*; CL(D&8v8~  
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mB bGj3u;  
public class SiteFileFetch extends Thread { N0K <zxR  
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SiteInfoBean siteInfoBean = null; //文件信息Bean mmNn,>AO!  
long[] nStartPos; //开始位置 -J]N &[  
long[] nEndPos; //结束位置 6
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FileSplitterFetch[] fileSplitterFetch; //子线程对象 1[a#blL6W  
long nFileLength; //文件长度 Ts=TaRwWf  
boolean bFirst = true; //是否第一次取文件 \qG` ts  
boolean bStop = false; //停止标志 CA$|3m9)NM  
File tmpFile; //文件下载的临时信息 ose)\rM'  
DataOutputStream output; //输出到文件的输出流 w#L`|cYCm  

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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） o9]!*Y!RA  
public SiteFileFetch(SiteInfoBean bean) throws IOException j/ARTaO1]"  
{ ~@}n}aV'!  
siteInfoBean = bean; ?AI`,*^  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); brqmi<*9"[  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 6HVX4Z#VH  
if(tmpFile.exists ()) 4~nf~  
{ gKWUHlQY  
bFirst = false; v806f8  
read_nPos(); \vL{f;2J  
} !L)|N<  
else 3|URlz  
{ @lh]?|*[  
nStartPos = new long[bean.getNSplitter()]; Y31e1   
nEndPos = new long[bean.getNSplitter()]; !0KNA1w,  
} =C)2DWJ1  
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} f{(D+7e}  
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public void run() 7<?Aou  
{ S[&yO-=p6  
//获得文件长度 oHu7<r  
//分割文件 hb)8
3mH}  
//实例FileSplitterFetch  [cfXcl  
//启动FileSplitterFetch线程 ,x[~|J!  
//等待子线程返回 X:(t,g*7  
try{ iE ,"YCK  
if(bFirst) P}!pmg6V  
{ /(}YjeS  
nFileLength = getFileSize(); PvxU.  
if(nFileLength == -1) PL3oV<\4s>  
{ 6\QsK96_  
System.err.println("File Length is not known!"); Qgo|\=  
} ExOSHKU,e  
else if(nFileLength == -2) Vg"vC  
{ ]==S?_.B3n  
System.err.println("File is not access!"); D*wY,\  
} *44E'Dxv  
else 2kFP;7FO  
{ t6%zfm   
for(int i=0;i<nStartPos.length;i++) P@Pe5H"o  
{ IfCa6g<&(  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); PiNf;b^
9  
} kNrd=s,-]D  
for(int i=0;i<nEndPos.length-1;i++) fQ2U|  
{ GM0pHmC  
nEndPos = nStartPos[i+1]; {-)I2GJav  
} _=I&zUF  
nEndPos[nEndPos.length-1] = nFileLength; |q\Rvt$d  
} <7MxI@\  
} v 5&8C  
#b;TjnC5{$  
~8lB#NuN  
//启动子线程 A] f^9F@  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; `k9a$@X
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for(int i=0;i<nStartPos.length;i++) 9%?a\#C  
{ >#5jO9  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), G4n-}R&'  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), *
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nStartPos,nEndPos,i); '=ydU+X  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); @dhnpR:L  
fileSplitterFetch.start(); ?T>)7Y)  
} $< .wQ8:Q  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), mfgUf  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); GrM`\MIO  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", &^F'ME  
nEndPos = " + nFileLength); !<5Wi)*  
// fileSplitterFetch[nPos.length-1].start(); 4 :M}Vz-  
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.  
//等待子线程结束 N9PEn[t@  
//int count = 0; yO J|t#  
//是否结束while循环 j=PM]  
boolean breakWhile = false; <*HsJwr)u  
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\{}5VVw-S?  
while(!bStop) r]bG,?|  
{ VO7&<Y}{x  
write_nPos(); "1-z'TV=  
Utility.sleep(500); S2~im?^21  
breakWhile = true; f2i9UZ$=e!  
e
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for(int i=0;i<nStartPos.length;i++) X[1w(dU[  
{ ##yH*{/&  
if(!fileSplitterFetch.bDownOver) zQsW*)L  
{ :gx]zxK  
breakWhile = false; i [2bz+Z?  
break; :eR\0cn  
} dPF*G$  
} 6'1Lu1w  
if(breakWhile) 0$.;EGP  
break; Zy^ wS1io  
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//count++; M HKnHPv  
//if(count>4) f(*iagEy  
// siteStop(); <-=g)3_  
} tjcG^m} _  
{[r}gS%  
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System.err.println("文件下载结束！"); g"X!&$
&  
} O7zj8  
catch(Exception e){e.printStackTrace ();} ?q}:ojrs1  
} \|C~VU@  
{:`XhPS<B  
YZ/2:[b  
//获得文件长度 'F Cmbry  
public long getFileSize() )bK3%>H#  
{ }ykc AK3U  
int nFileLength = -1; Y?JB%%WWI  
try{
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URL url = new URL(siteInfoBean.getSSiteURL()); ?2Sm f  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); kntULI$`  
httpConnection.setRequestProperty("User-Agent","NetFox"); %[k"A  
j.SE'a_  
~.J{yrJ&  
int responseCode=httpConnection.getResponseCode(); aoU5pftC  
if(responseCode>=400) ~p\r( B7G  
{ +Al*MusS  
processErrorCode(responseCode);
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return -2; //-2 represent access is error -}"nb-RR\  
} ffem7eQ  
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String sHeader; J
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for(int i=1;;i++) -n6e;p]  
{ He}"e&K  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); h%Uq  
//Utility.log(in.readLine()); (
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sHeader=httpConnection.getHeaderFieldKey(i); dRXrI  
if(sHeader!=null) LCok4N$o  
{ D #C\| E:  
if(sHeader.equals("Content-Length")) O2oF\E_6  
{ Twpk@2=l  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); }}4uLGu)  
break; i6xzHfaYG  
} F[~~fm_  
} k3&/Ei5  
else C@9K`N[*  
break; "Q;Vy t  
} ;H"OZRQ  
} 4gn|zSe>^  
catch(IOException e){e.printStackTrace ();} km6O3>p5r  
catch(Exception e){e.printStackTrace ();} 4}*V=>z  
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Utility.log(nFileLength); I\('b9"*  
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return nFileLength; LN=#&7=$c  
} a!;CY
1>  
#[y2nK3zF  
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//保存下载信息（文件指针位置） Dx.hM[  
private void write_nPos() DN|+d{^lN  
{ 8FgF6ip  
try{ r ['zp=9  
output = new DataOutputStream(new FileOutputStream(tmpFile)); )4jS}  
output.writeInt(nStartPos.length); @Qd5a(5WM  
for(int i=0;i<nStartPos.length;i++) s"X0Jx}
 
{ H=*2A!O[_  
// output.writeLong(nPos); {&pBy  
output.writeLong(fileSplitterFetch.nStartPos); ,-1d2y  
output.writeLong(fileSplitterFetch.nEndPos); M0woJt[&  
} q`HK4~i,  
output.close(); $QaEU="Z  
} S vW{1  
catch(IOException e){e.printStackTrace ();} h`Xl~=
 
catch(Exception e){e.printStackTrace ();} xhncQhf\  
} FF#?x@N:  
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//读取保存的下载信息（文件指针位置） cEEnR1  
private void read_nPos() 2\G[U#~bi  
{ r,wC5%&Za  
try{ Q-||A  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Q57Z~EsF  
int nCount = input.readInt(); ?7w7Y;FuR  
nStartPos = new long[nCount]; HVNX"`]"  
nEndPos = new long[nCount]; HUx-8<ws  
for(int i=0;i<nStartPos.length;i++) L%/atl!  
{ ky[^uQ>0  
nStartPos = input.readLong(); QX+&[G!DZH  
nEndPos = input.readLong(); [B%:!Q)@  
} {N@tJ,Fh{  
input.close(); D1cnf"y^  
} *.+N?%sAP)  
catch(IOException e){e.printStackTrace ();} 6tup^Rlo;$  
catch(Exception e){e.printStackTrace ();} #x(3>}  
} ]9hhAT44  
/rv=mlpRL  
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private void processErrorCode(int nErrorCode) TR!7@Mu3  
{ v8K4u)  
System.err.println("Error Code : " + nErrorCode); X9#i!_*  
} *%2,= p  
}Hb_8P  
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//停止文件下载 +xBM\Dz8  
public void siteStop() !$fF3^8-  
{ 4JGU`L:~  
bStop = true; )D ':bWP  
for(int i=0;i<nStartPos.length;i++) h~k+!\  
fileSplitterFetch.splitterStop(); _j|U>s   
13/U4-%b2  
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} J%8hf%!ud  
} l,ra
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//负责部分文件的抓取 EP8R[Q0_"  
**FileSplitterFetch.java >!#or- C  
*/ Ej'N!d.  
package NetFox; 6KKQ)DNu_  
]?~[!&h  
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import java.io.*; [ejl #'*5  
import java.net.*; `B7?F$J  
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public class FileSplitterFetch extends Thread { ;>jOB>b{h  
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String sURL; //File URL l"9$lF}
 
long nStartPos; //File Snippet Start Position uar[D|DcD"  
long nEndPos; //File Snippet End Position -FQS5Zb.!  
int nThreadID; //Thread's ID poXT)2^)  
boolean bDownOver = false; //Downing is over MMf_  
boolean bStop = false; //Stop identical Io<L! =>  
FileAccessI fileAccessI = null; //File Access interface 9D51@b6k  
~lH2#u>g  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ie<m)  
{ Vet<,;Te  
this.sURL = sURL; h($Jo  
this.nStartPos = nStart;
{D4N=#tl  
this.nEndPos = nEnd; / 2h
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nThreadID = id; (0zYS_mA  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 l#|M.V6G  
} &F|Wk,y  
qQCds}<w  
Z/b,aZhB  
public void run() B-tLRLWn   
{ ^-7-jZ@jz  
while(nStartPos < nEndPos && !bStop) [};?;YN  
{ Q@.%^1Mp  
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|=EwZmj-c  
try{ 1Ewg_/R  
URL url = new URL(sURL); ~}s0~j~  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); B{lL}"++0  
httpConnection.setRequestProperty("User-Agent","NetFox"); (t"rzH  
String sProperty = "bytes="+nStartPos+"-"; wy?Hp*E  
httpConnection.setRequestProperty("RANGE",sProperty); @gihIysf  
Utility.log(sProperty); (:|1h@K/R  
"oT]_WHqo  
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InputStream input = httpConnection.getInputStream(); PF:E{_~  
//logResponseHead(httpConnection); :6}cczQE|O  
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1:Xg&4s  
byte[] b = new byte[1024]; !4mAZF b  
int nRead; |@*   
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) UymhBh  
{ QjyJmW("Z  
nStartPos += fileAccessI.write(b,0,nRead); SNtOHTQ  
//if(nThreadID == 1) ()
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// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); <"x *ZT  
} Owm2/  
+c\uBrlZQ;  
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Utility.log("Thread " + nThreadID + " is over!"); 8YkCTJfBGu  
bDownOver = true; i-Ri;E  
//nPos = fileAccessI.write (b,0,nRead); _O"C`]]  
} [,q^\T  
catch(Exception e){e.printStackTrace ();} $EPDa?$*  
} /G#W/Q  
} rvBKJ!b0  
/V!gF+L  
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//打印回应的头信息 ]8EkZC  
public void logResponseHead(HttpURLConnection con) BaE}|4  
{ SRc|9W5t*J  
for(int i=1;;i++) @RLlkWGc  
{ -/J2;AkGH  
String header=con.getHeaderFieldKey(i);
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if(header!=null) 4I3)eS%2  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); R|dSjEs  
Utility.log(header+" : "+con.getHeaderField(header)); Z%I9:(  
else E0"DHjR  
break; Xe\,:~  
} kF7`R4Sz  
} ,4kipJ!,yK  
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public void splitterStop() 'pl){aL`@u  
{ 4t0-L]v4.*  
bStop = true; j0IuuJ+  
} !6{b)P  
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} M@O<b-  
_@ @"'  
cUM#|K#6  
/* ,ikn%l#cm  
**FileAccess.java
/BfCh(B  
*//文件访问(定位，写) B,RHFlp{  
package NetFox; ~n!7 ?4%U  
import java.io.*; C~:!WRCz  
iVb#X#  
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public class FileAccessI implements Serializable{ }J\KnaKo  
8:t1%O$  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 %'<m[wf^ o  
RandomAccessFile oSavedFile; >`+-Yi$(\  
long nPos; 407;M%?'A  
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public FileAccessI() throws IOException hOF>Dj  
{ Y%]&h#F  
this("",0); Cr%6c3aQ  
} Nyo,6 AA  
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t&Z:G<;  
public FileAccessI(String sName,long nPos) throws IOException qf6}\0   
{ SZ"^>}zl=  
oSavedFile = new RandomAccessFile(sName,"rw"); v0S7 ]?_  
this.nPos = nPos; ShRkL<  
oSavedFile.seek(nPos); ];G$~[  
} 0P6< 4  

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&fWYQ'\>  
public synchronized int write(byte[] b,int nStart,int nLen) OL)M`eVQ'  
{  p(Bn!  
int n = -1; |p{FSS  
try{ \.jT"Z~  
oSavedFile.write(b,nStart,nLen); ZVmgQ7m  
n = nLen; OQZ\/~o 5  
} EL-1o02-  
catch(IOException e) IEJ
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{ 
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e.printStackTrace (); WXC}Ie  
} } ~#^FFe  
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return n; "Crm\UI6  
} dLI`\e<r&[  
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} 3Q"4-pd  
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1ssEJ;#s  
/* r)SwV!b  
**SiteInfoBean.java /R44x\nhr  
*/ L(!mm  
package NetFox; gKGM|0u|r  
A1,- qv1s  
#.n%$r  
public class SiteInfoBean { <xeo9'k6&  
y*5bF0  
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private String sSiteURL; //Site's URL )#l,RJ(  
private String sFilePath; //Saved File's Path @7aSq-(_l*  
private String sFileName; //Saved File's Name _ s[v:c  
private int nSplitter; //Count of Splited Downloading File zn|/h,.  
@}cZxFQ!C  
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public SiteInfoBean() A_WtmG_9  
{//nSplitter的缺省值为5 &u/T,jy`  
//default value of nSplitter is 5 zWh[U'6  
this("","","",5); ]o]*&[C  
} cCH2=v4hU  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) e-#!3j!'  
{ 7}<057Xn'  
sSiteURL= sURL; s$ 2@|;  
sFilePath = sPath; @n##.th  
sFileName = sName; /hMD Me  
this.nSplitter = nSpiltter; 'M#'BQQ5  
|VL(#U  
IL]VY1'#  
} &zYo   
,??%["R  
F
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public String getSSiteURL() B)M& FO  
{ $}/ !mXI5  
return sSiteURL; bLysUj5[5  
} HwH Wi  
93npzpge  
 TVP.)%  
public void setSSiteURL(String value) i>C:C>~  
{ ;ip"V 0`  
sSiteURL = value; hd2 X/"  
} N}3$1=@Y  
6h|@Bz/A  
r%g?.4o*b  
public String getSFilePath() +0Rr5^8u  
{ 0/."R;  
return sFilePath; ;_lEu" -  
} 8@|rB3J  
}'KVi=qnHb  
VBIY[2zf  
public void setSFilePath(String value) x^|J-
  
{ YEWHr>&Z  
sFilePath = value; [~ sXjaL8  
} *8uSy/l  
GP5Y5)  
pCQB<6&1N  
public String getSFileName() =x4:jas  
{ ,xew3c'(W  
return sFileName; b&;1b<BwD  
} XK (y ?Y1  
l0 H,TT~2  
3 G?^/nB  
public void setSFileName(String value) pH%cbBm  
{ Ab<4F7  
sFileName = value; oOhm`7iy  
} e4V4%Q
w  
AT:T%a:G?  
d))(hk:  
public int getNSplitter() .3%eSbt0  
{ :Gh* d)
 
return nSplitter; rdsm /^,s  
} $Gs&' yR  
->oQ,ezB  
pHFh7-vj  
public void setNSplitter(int nCount) }*~EA=YN;  
{ 7 N?x29  
nSplitter = nCount; `MgR/@%hr  
} `CI9~h@k  
} \guZc}V]:\  
.[hQ#3)W  
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/* 6rEt!v #K[  
**Utility.java *Rv e
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*/ !<!sB)  
package NetFox; kSH3)CC P  
b'^OW  
O/wl";-  
public class Utility { I72UkmK`  
}ZEh^zdz8  
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public Utility() M#JOX/  
{ SzR0Mu3uK  
[IVT0 i  
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} z I`'n%n=  
UAT46  
//线程睡眠 %Yg;s'F>#q  
public static void sleep(int nSecond) j=)Cyg3_%  
{ z0Vd(QL  
try{ ,9q=2V[GP  
Thread.sleep(nSecond); h'<}
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} ch<Fi%)  
catch(Exception e) GV1\8OG7  
{ QeA)@x.p  
e.printStackTrace (); K6kPNi  
} kx'ncxN~  
} &J_|P43  
YNbs*i&  
//日志 
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public static void log(String sMsg) +vkqig  
{ 5nr}5bum  
System.err.println(sMsg); lnW/T--  
} sJX/YGHt  
>U^AIaW  
!arcQ:T@G  
public static void log(int sMsg) YWeEvo(,=  
{ %*<k5#Yq  
System.err.println(sMsg); <pGPuw|~I  
} g# :|Mjgh  
} {a9Z<
P  
??{(.`}R~  
-8qLshQ  
/* 9Ps:]Kp!vN  
**TestMethod.java fcb:LPk;  
*/ k+44ud.j  
package NetFox; qFW- ~T  
^aDos9SyV  
gLQWL}0O  
public class TestMethod {  x;LyR  
:7IL|bA<  
P"_x/C(]@J  
public TestMethod() &by,uVb=|{  
{ ///xx/weblogic60b2_win.exe 71cc6T  
try{ ?]f+)tCMs  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); =2bW"gs I  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); je.jui"  
SiteFileFetch fileFetch = new SiteFileFetch(bean); (`4^|_gw  
fileFetch.start(); -:m;ePK  
} 4QK([q  
catch(Exception e){e.printStackTrace ();} JiP]FJ;  
6}IOUWLB@  
8iD_md_[  
} h$~ NPX  
%|Gi'-'|b$  
YWM$%  
public static void main(String[] args) zY(*Xk  
{ .txgb  
new TestMethod(); j*Q/
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} Gp$[u4-6M6  
} nTY`1w.;  
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