http断点续传简单实现（java)

/* oM)4""|
 
**SiteFileFetch.java !nyUAZ9 :  
*/ iXFN|ml  
package NetFox; p/.[cH  
import java.io.*; e6igx  
import java.net.*; ICB'?yZ,  
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public class SiteFileFetch extends Thread { c;1Xu1  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ZsepTtY  
long[] nStartPos; //开始位置 f1}b;JJTsv  
long[] nEndPos; //结束位置 8nOent0a  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 9Z;"9$+M  
long nFileLength; //文件长度 M8iI e:{ c  
boolean bFirst = true; //是否第一次取文件 Aq"<#:  
boolean bStop = false; //停止标志 $09PZBF,i  
File tmpFile; //文件下载的临时信息 ;,F:.<P  
DataOutputStream output; //输出到文件的输出流 CXfPC[o  
'*,P33h9<!  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类）
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public SiteFileFetch(SiteInfoBean bean) throws IOException f+j-M|A  
{ hp)k[|u;  
siteInfoBean = bean; 3# r`e  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); R=u!RcvR  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); + c"$-Jr  
if(tmpFile.exists ()) }_"<2
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{ lVc':,z  
bFirst = false; _4h[q4Z  
read_nPos(); >zY~")|R(  
} mzh7E[S_,i  
else Wo8.tu-2  
{ z'd*z[L~  
nStartPos = new long[bean.getNSplitter()]; NamO5(1C  
nEndPos = new long[bean.getNSplitter()]; !JC!GS"M5  
} Mk$Pt  
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"
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} wUBug  
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public void run() Q]oCzSi  
{ (S4[,Sx6E  
//获得文件长度 CEr*VsvjsU  
//分割文件 gm}[`GMU  
//实例FileSplitterFetch T)"LuC#C
 
//启动FileSplitterFetch线程 o\7q!  
//等待子线程返回 o$,Dh?l  
try{ I3$/#  
if(bFirst) C~#ndl Ij  
{ C=|X]"*:u0  
nFileLength = getFileSize(); H[KTM
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if(nFileLength == -1) D%NVqk|  
{ BavGirCp  
System.err.println("File Length is not known!"); {s/u[T_D2  
} 't:s6  
else if(nFileLength == -2) -32?]LN}  
{ m^rrbU+HM?  
System.err.println("File is not access!"); iS%md  
} K4>nBvZ?v  
else >4N=
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{ _wMYA8n  
for(int i=0;i<nStartPos.length;i++) pJpTOq\h  
{ rAZsVnk?  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); cw)'vAE  
} ubvXpK:.  
for(int i=0;i<nEndPos.length-1;i++) &z"sT*3  
{ loPBHoE3@H  
nEndPos = nStartPos[i+1]; q&`>&k  
} O=LiCSNEV  
nEndPos[nEndPos.length-1] = nFileLength; >
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} o}4J|@Hi|4  
} uk)6%  
=
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Sd0y=!Pj=  
//启动子线程 v%6mH6V  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; :n t\uwh  
for(int i=0;i<nStartPos.length;i++) g9$P J:  
{ hy?e?^  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), kbF+aS  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), NDv_@V(D  
nStartPos,nEndPos,i); )Ap0" ?q  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); sF=8E8qa  
fileSplitterFetch.start(); D+:}D*_&  
} t/HUG#W{  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), %ymM#5A  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); j%y)%4F8  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", !e"TWO*X  
nEndPos = " + nFileLength); -P5M(Rt  
// fileSplitterFetch[nPos.length-1].start(); \X?GzQkr  
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/  
yF#:*Vz>  
//等待子线程结束 O]nZr  
//int count = 0; 6+;B2;*3  
//是否结束while循环 m{)F9F  
boolean breakWhile = false; \HsrUZ~  
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while(!bStop) 'Oe}Ja  
{ "ccP,#Y  
write_nPos(); }N6r/ VtOQ  
Utility.sleep(500); d^Jf(NE0Yo  
breakWhile = true; 4}\Dr %US  
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for(int i=0;i<nStartPos.length;i++) w[
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{ b&$sY!iU  
if(!fileSplitterFetch.bDownOver) [qEd`8V(  
{ h5.>};"@'  
breakWhile = false; lN-[2vT<  
break; !]-ET7  
} X+*"FKm S.  
} B
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if(breakWhile) uWSfr(loX  
break; QE8aYPSFf  
eT|"6WJ:{  
< x==T4n/  
//count++; 34$qV{Y%y  
//if(count>4) Lb>UraUvL  
// siteStop(); bz=B&YR  
} 8+irul{H_  
[7:(e/&  
F9SkEf]99  
System.err.println("文件下载结束！"); mJ3|UClPS  
} <CJ`A5N  
catch(Exception e){e.printStackTrace ();} {{\ d5CkX  
} pM^r8kIH  
zeZ}P>C  
iB:](Md'r  
//获得文件长度 F5#P{zk|  
public long getFileSize() 9Fkzt=(E~  
{ S1R:/9 z  
int nFileLength = -1; nDhD"rc  
try{ y^SDt3Am  
URL url = new URL(siteInfoBean.getSSiteURL()); V+M=@Pvp9  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); #!WD1a?L  
httpConnection.setRequestProperty("User-Agent","NetFox"); pd[?TyVK;  
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int responseCode=httpConnection.getResponseCode(); 5V^+;
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if(responseCode>=400) zoU-*Rs6  
{ -zq_W+)ks  
processErrorCode(responseCode); Z3)l5JG)  
return -2; //-2 represent access is error 7:h8b/9  
} iA^GA8dn  
XA$Z7_gu3  
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String sHeader; f0^DsP  
iYyJq;
S   
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for(int i=1;;i++) uH6QK\  
{ 0PK*ULwSN  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 3r)<:4a u&  
//Utility.log(in.readLine()); ^_cR  
sHeader=httpConnection.getHeaderFieldKey(i); c%|18dV  
if(sHeader!=null) ;L
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{ 5DHFxym'  
if(sHeader.equals("Content-Length")) Ny.s u?E  
{ F`3J=AJOJ  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); L0Fhjbc  
break; (oYM}#Q  
} V=@M!;'<  
} :d7tzYT ^  
else M]+FTz  
break; Ier0F7]I  
} !i|]OnJY  
} ZS-O,[  
catch(IOException e){e.printStackTrace ();} 5F8sigr/h  
catch(Exception e){e.printStackTrace ();} bOi`JJ^  
{!B^nCSL  
8?L7h\)-  
Utility.log(nFileLength); g]=w_  
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return nFileLength; u_C/Y[ik  
} /uc*V6Xd (  
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6<h?%j(  
//保存下载信息（文件指针位置） v\Y362Xv  
private void write_nPos() 6%K,3R-d  
{ gCMwmanX  
try{ @q?zh'@;  
output = new DataOutputStream(new FileOutputStream(tmpFile)); O>=D1no*  
output.writeInt(nStartPos.length); )V}u}5  
for(int i=0;i<nStartPos.length;i++) uKI2KWU?2  
{ 6QCU:2IiL  
// output.writeLong(nPos); BCE}Er&  
output.writeLong(fileSplitterFetch.nStartPos); i#@3\&{J>  
output.writeLong(fileSplitterFetch.nEndPos); v.08,P
{b  
} .{-&3++WZ  
output.close(); ]#C;)Vy  
} Vp;^_,
  
catch(IOException e){e.printStackTrace ();} *g}(qjl<  
catch(Exception e){e.printStackTrace ();} X0=#e54  
} ;OlC^\e  
2Mc}>UI?eO  
::\7s  
//读取保存的下载信息（文件指针位置） (W<n<sl:-  
private void read_nPos() p+O2:  
{ 6wzTX8  
try{ X]?qns7  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 6$}hb|j  
int nCount = input.readInt(); YGBVGpE9  
nStartPos = new long[nCount]; Y5}<7s\UDO  
nEndPos = new long[nCount]; `&.]>H)N*  
for(int i=0;i<nStartPos.length;i++) AeqxH1%  
{ Z
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nStartPos = input.readLong(); pU4B6
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nEndPos = input.readLong(); O\64)V 0  
} YQzs0t ,  
input.close(); D&0@k'  
} Y7{9C*>  
catch(IOException e){e.printStackTrace ();} I/ pv0  
catch(Exception e){e.printStackTrace ();} K<HF!YU#I2  
} \X5>HPB  
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: QK )Ym  
private void processErrorCode(int nErrorCode) qwlIz/j  
{ 7|A9  
System.err.println("Error Code : " + nErrorCode); FK MuRy|  
} PYldqY   
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O
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//停止文件下载 MPINxS  
public void siteStop() \($EYhx  
{ "y_A xOH  
bStop = true; &;~x{q]3  
for(int i=0;i<nStartPos.length;i++) o}XbFLn  
fileSplitterFetch.splitterStop(); `%lgT+~T  
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} S7cxEOfAu  
} P +U=/$o  
//负责部分文件的抓取 26fbBt8nP  
**FileSplitterFetch.java rBv  
*/ S!0ocS!t  
package NetFox; {wWh;  
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:I(-@2?{  
import java.io.*; $V$|"KRcs  
import java.net.*; Sm
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public class FileSplitterFetch extends Thread { 3YyB0BMW  
"(uEcS2<  
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String sURL; //File URL 4}:a"1P"  
long nStartPos; //File Snippet Start Position t_@xzt10y  
long nEndPos; //File Snippet End Position 'H0b1t1S%  
int nThreadID; //Thread's ID o(iN}.c  
boolean bDownOver = false; //Downing is over ;~Eb Q  
boolean bStop = false; //Stop identical $:I~y| !1  
FileAccessI fileAccessI = null; //File Access interface @D!KFJ  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException uf;^yQi  
{ $9v:(:!Bm  
this.sURL = sURL; y6|&bJ @  
this.nStartPos = nStart; T<*i($ [  
this.nEndPos = nEnd; ~Uw**PT3M  
nThreadID = id; 6,j6,Q(67  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 qGtXReK  
} =;.#Bds  
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public void run() m2[q*k]AtS  
{ v~>^c1:  
while(nStartPos < nEndPos && !bStop) =F2e*?a3  
{ FL5u68  
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try{ sidSY8j  
URL url = new URL(sURL); ar
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 7dl]f#uZU  
httpConnection.setRequestProperty("User-Agent","NetFox"); JV|GEn\@N  
String sProperty = "bytes="+nStartPos+"-"; C<CE!|sfr  
httpConnection.setRequestProperty("RANGE",sProperty); k$nQY  
Utility.log(sProperty); RsJj*REO  
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InputStream input = httpConnection.getInputStream(); 0r=:l/Pz  
//logResponseHead(httpConnection); Y|FJ1x$r  
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byte[] b = new byte[1024]; /[YH W]  
int nRead; M9{?gM9  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) b?-Ep?G'\  
{ )>q.!
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nStartPos += fileAccessI.write(b,0,nRead); 7_ g}t!b`  
//if(nThreadID == 1) 8=x{>&Jr&#  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); D T^3K5  
} Ilvz@=  
oXG,8NOdC  
N%{&%C6{  
Utility.log("Thread " + nThreadID + " is over!"); ;+XiDEX0}  
bDownOver = true; "J(#|v0  
//nPos = fileAccessI.write (b,0,nRead); iivuH2/~?[  
} pX ]K-  
catch(Exception e){e.printStackTrace ();} mc_`:I=  
} wXf_2qB9  
} is`Eqcj`dr  
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//打印回应的头信息 gCAWRNp  
public void logResponseHead(HttpURLConnection con) Wd'wL"6De  
{ o >bf7+D  
for(int i=1;;i++) Eh;SH^&6  
{ !h&A^sAc  
String header=con.getHeaderFieldKey(i); (v*$ExF  
if(header!=null) 9,y*kC  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); #"%=7(

 
Utility.log(header+" : "+con.getHeaderField(header)); _A%} >:q  
else R*I{?+  
break; VJ P]Jy_  
} ^+cf  
} )`]w\s #  
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public void splitterStop() RrSo`q-h+  
{ yjZxD[ Z  
bStop = true; \3w=')({  
} n'ft@7>%h  
{'8a'
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} :|xV}  
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/* A][\L[8X  
**FileAccess.java jJ86Ch  
*//文件访问(定位，写) Pb=J4Lvz(d  
package NetFox; (</cu$w>H)  
import java.io.*; Dt\F]\6sd  
}ex2tkz  
niY9`8  
public class FileAccessI implements Serializable{ ='<0z?Af  
4;8 Z?.  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 C#X|U2$  
RandomAccessFile oSavedFile; =if
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long nPos; qJ!&H  
D 4^2F(YRX  
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public FileAccessI() throws IOException ?fcQd6-}  
{ U.UN=uv_  
this("",0); 2'W3:   
} nE)?P*$3Z  
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public FileAccessI(String sName,long nPos) throws IOException I$v*SeVHE  
{ ,o\vumx  
oSavedFile = new RandomAccessFile(sName,"rw"); !u@e^J{Ao  
this.nPos = nPos; 09pnM|8A  
oSavedFile.seek(nPos); G (Fi  
} %c)^8k;I  
+/*,%TdQ4  
GQO}E@W6C  
public synchronized int write(byte[] b,int nStart,int nLen) io^^f|  
{ Ul7)CT2:  
int n = -1; 7a 4G:  
try{ W\gu"g`u  
oSavedFile.write(b,nStart,nLen); U#R=y:O?  
n = nLen; ]Ow A>fb  
} 7:t+  
catch(IOException e)  6!])\Ay  
{ d4F3!*@(  
e.printStackTrace (); +s.r!?49+  
} 6}A1^RB+w  
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return n; p7}xgUxX  
} 
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} xpt*S~  
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/* wYK-YY:Q3  
**SiteInfoBean.java !8M]n  
*/ vx /NG$  
package NetFox; jHq.W95+P  
hb'S!N5m  
&m_4#  
public class SiteInfoBean { \&|)?'8rS  
H->J.5~,K  
V9qA.NV2  
private String sSiteURL; //Site's URL ,[&@?  
private String sFilePath; //Saved File's Path 0q(}nv  
private String sFileName; //Saved File's Name EOWLGleD1  
private int nSplitter; //Count of Splited Downloading File pme5frM|  
'v iF8?_  

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public SiteInfoBean() l -us j%\  
{//nSplitter的缺省值为5 -bT1Qh X  
//default value of nSplitter is 5 -v#0.3zm  
this("","","",5); -R@mnG 5  
} #x!h BS!  
2bwf(  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) fF37P8Ir  
{ ={y Mk  
sSiteURL= sURL; @w|'ip5@  
sFilePath = sPath; dBkw.VOW  
sFileName = sName; u*0Ck*pZ  
this.nSplitter = nSpiltter; FjD`bhw-  
vfPL;__{Y]  
.XQ_,  
} ;:NW  
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public String getSSiteURL() 9q;n@q:29  
{ "pGSz%i-  
return sSiteURL; }S|~^  
} 3(l^{YC+[7  
d[(KgX9  
N0h
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public void setSSiteURL(String value) 'N#,,d/G  
{ H$Om{r1j  
sSiteURL = value; }DiMt4!ZC!  
} 9BgR@b  
QQ^P IQj  
]Z%9l(  
public String getSFilePath() ~Qjf-|  
{ 7:'7EqM  
return sFilePath; V'y,{YpP  
} $6Z@0H@X  
9M{z@H/  
nw|ls2  
public void setSFilePath(String value) jt5en;AA[  
{ dHjJLs_  
sFilePath = value; WBdC}S }3t  
} k!-(Qfz  
uBp"YX9rx  
ea!_/Y  
public String getSFileName() ,q$'hYTaJ  
{
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return sFileName; MBZ/Pzl~  
} *mH+
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public void setSFileName(String value) AB92R/  
{ HAJK%zLc  
sFileName = value; CYD&#+o  
} 8wJfGY  
;G!JKg  
N
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public int getNSplitter() . AJ(nJ)  
{ rbfP6t:c3  
return nSplitter; NVqJN$z  
} ^5n"L29V  
}cUq1r-bW  
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public void setNSplitter(int nCount) stn/  
{ .;#Wf@V  
nSplitter = nCount; I6!~(ND7  
} ?86q8E3;&  
} A"Q6GM2;Io  
LDilrG)  
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/* ft
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**Utility.java "SGq$3D  
*/ );X&J:-l+  
package NetFox; -L=aZPW`M  
>9F&x>~  
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public class Utility { ;jC}.] _)w  
};{V]f 0  
BC|=-^(  
public Utility() [Aqy%mbG  
{ :Y/>] tS4  
VHwAO:+-  
dV_ClH &)  
} EC
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_J' _9M?>  
//线程睡眠 Vu6$84>-,  
public static void sleep(int nSecond) A{3VTe4TV  
{ 3.[ fTrzJ  
try{ J0xV\O !e  
Thread.sleep(nSecond); )?es3Ehqq  
} 4KH8dau.fF  
catch(Exception e) .;),e#  
{ ']]Czze  
e.printStackTrace (); N$cm;G=]  
} fGK=lT$  
} >iE/t$%1  
T["(wPrt  
//日志 8n_!WDD  
public static void log(String sMsg) H?\b   
{ wrtJ8O(  
System.err.println(sMsg); -B+Pl*  
} ~cC=DeX  
SxyXz8+e[  
^t X}5i`P  
public static void log(int sMsg) O}$@|w(8;  
{ V5ve  
System.err.println(sMsg); ST'eJ5P7!5  
} ^ud-N;]MKs  
} LmCr[9/  
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R<* c  
/* J3 Y-d7=|  
**TestMethod.java k :KN32%  
*/ 3W&f^*  
package NetFox; #Tm^$\*h\]  
}q8|t3  
"$@>n(w  
public class TestMethod { Q&Q$;s3|Y  
TU-aL  
. #+N?D<  
public TestMethod() }K<% h  
{ ///xx/weblogic60b2_win.exe }bkQr)us  
try{ qeM`z  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); k 5~#_D>  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); h`{agWB  
SiteFileFetch fileFetch = new SiteFileFetch(bean); k&oq6!ix  
fileFetch.start(); o p{DPUO0  
} No
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catch(Exception e){e.printStackTrace ();} fLGZ@-qA0  
pv LA:LW2  
^v5v7\!  
} P|0dZHpT  
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$9~6M*  
public static void main(String[] args) yaDK_fk  
{ kK62yz,  
new TestMethod(); <in#_Of{E  
} 0ZRIi70u  
} *!mT#Vm^  
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