http断点续传简单实现（java)

/* xsWur(>]  
**SiteFileFetch.java KNH1#30 K  
*/ v<Bynd-  
package NetFox; u2 `b'R9  
import java.io.*; 2]%h$f+  
import java.net.*; Bl=tYp|a  
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public class SiteFileFetch extends Thread { ^CwR!I.D}4  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 2^?:&1:  
long[] nStartPos; //开始位置 v4@Z(M  
long[] nEndPos; //结束位置 n3J53| %v  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 cwGbSW$t  
long nFileLength; //文件长度 NcY608C  
boolean bFirst = true; //是否第一次取文件 }9nDo*A"}  
boolean bStop = false; //停止标志 9"g6C<  
File tmpFile; //文件下载的临时信息 c-.t>r&  
DataOutputStream output; //输出到文件的输出流 $-[CG7VgX%  
1S@vGq}  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） JxyB(
 
public SiteFileFetch(SiteInfoBean bean) throws IOException q^6+!&"  
{ B]tIi^  
siteInfoBean = bean; 1sYEZO;  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); m3o,@=b  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); O%r;5kP  
if(tmpFile.exists ())
;WldHaZ9r  
{ ^MBm==heL  
bFirst = false; =4h+ M$2  
read_nPos(); JEE{QjTh  
} fGmT_C0t  
else SNY~9:;]f  
{ *Q1~S]g  
nStartPos = new long[bean.getNSplitter()]; ]9\!;Bz^J  
nEndPos = new long[bean.getNSplitter()]; P./VmY'  
} c6Y\n%d&  
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} ? w^-  
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public void run() ETB6f  
{ O:da-xWJ  
//获得文件长度 p ;|jI1  
//分割文件 I$8" N]/C  
//实例FileSplitterFetch NH3cq  
//启动FileSplitterFetch线程 z $MV%F  
//等待子线程返回 S4=R^];l  
try{ `9 {mr<  
if(bFirst) 
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{ s|D>-  
nFileLength = getFileSize(); LdB($4,  
if(nFileLength == -1) 3"rzb]=R  
{ 1h.)#g?{  
System.err.println("File Length is not known!"); wY"Q o7  
} 7.j[a*^  
else if(nFileLength == -2) .;&# )l
 
{ '?({;/L  
System.err.println("File is not access!"); %$TGzK1  
} p019)X|vx  
else }2ZsHM^]%  
{ Ko^c|}mh*!  
for(int i=0;i<nStartPos.length;i++) Vx @|O%  
{ Yq/.-4y  
nStartPos = (long)(i*(nFileLength/nStartPos.length));  YBnA+l*  
} 'g9"Qv?0{`  
for(int i=0;i<nEndPos.length-1;i++) [V}S<Xp  
{ ]D,MiDph  
nEndPos = nStartPos[i+1]; frBX{L  
} !Kv@\4  
nEndPos[nEndPos.length-1] = nFileLength; A19;1#$=  
} Ja ,Cvt  
} k^OV56  
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//启动子线程 t+Op@*#%  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; p6vKoI#T  
for(int i=0;i<nStartPos.length;i++) /y>>JxAEb  
{ mA{~PpSb  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), [xKd7"d/n  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), iPrLwheb  
nStartPos,nEndPos,i); N:9>dpP}O  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 8|$3OVS  
fileSplitterFetch.start(); Ka,^OW}<%q  
} B4]`-mahO  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ]~\sA
  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); qgDRu]ba  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", }mZwd_cK  
nEndPos = " + nFileLength); <r3J0)r
}  
// fileSplitterFetch[nPos.length-1].start(); JCW\ *R  
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//等待子线程结束 It75R}B  
//int count = 0; pa{re,O"e  
//是否结束while循环 KWWa&[ev)  
boolean breakWhile = false; 1nu^F,M  
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while(!bStop) mLL340c#\  
{ 1LJUr"6]  
write_nPos(); >fIk;6
<{  
Utility.sleep(500); mJM_2Ab  
breakWhile = true; ?)\a_Tn  
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for(int i=0;i<nStartPos.length;i++) b?eu jxqg  
{ _A0w[n  
if(!fileSplitterFetch.bDownOver) r$wxk 4%Rz  
{ ~gu3g^<0v  
breakWhile = false; 6[]]Y,Y  
break; !`7B^RZ  
} ~0b O}  
} Zo{$  
if(breakWhile) 5#QXR+ T   
break; 4npqJ1  
\);4F=h}f  
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//count++; Sv;_HZ  
//if(count>4) m%PC8bf`S  
// siteStop(); l|hUw  
} d,by/.2  

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System.err.println("文件下载结束！"); 7L^%x3-|&  
} Xo*
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catch(Exception e){e.printStackTrace ();} sp*Vqd  
} 03j]d&P%d  
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//获得文件长度 |g3?y/l  
public long getFileSize() JBnKK  
{ 'L{8@gqi  
int nFileLength = -1; AL5Vu$V~n}  
try{ z(\4M==2O  
URL url = new URL(siteInfoBean.getSSiteURL()); 7w1wr)qSB  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 0dh=fcb  
httpConnection.setRequestProperty("User-Agent","NetFox"); 8 B**8yg.  
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int responseCode=httpConnection.getResponseCode(); !s@Rok  
if(responseCode>=400) ^3hn0DVQ  
{ %e@HZ"V  
processErrorCode(responseCode); |!F5.%PY  
return -2; //-2 represent access is error [NFNzwUB  
} &)oOeRwi].  
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String sHeader; _`#3f1F@[  
&5L<i3BX  
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for(int i=1;;i++) b}Zd)2G  
{ Wpc|`e<  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); _{|D  
//Utility.log(in.readLine()); 2On_'^O  
sHeader=httpConnection.getHeaderFieldKey(i); fQP{|+4  
if(sHeader!=null) q{ /3V  
{ Pm$q]A~  
if(sHeader.equals("Content-Length")) I7&_Xr  
{ }y%oT P&  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); [{r}u  
break; ai*f F  
} i>[_r,-\[  
} 0 u?{\  
else vF?5].T  
break; [ 4;Ii  
} HV/cc"  
} dik9 >*"|o  
catch(IOException e){e.printStackTrace ();} = P   
catch(Exception e){e.printStackTrace ();} TO-$B8*nq  

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Utility.log(nFileLength); |+$%kJR=  
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return nFileLength; 3/#:~a9Q  
} cJgBI(S5  
,TRTRb;  
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//保存下载信息（文件指针位置） .%zy`n  
private void write_nPos() GQ_p-/p R  
{ Erk?}E  
try{ 0<TD/1wN  
output = new DataOutputStream(new FileOutputStream(tmpFile)); vS;1/->WD  
output.writeInt(nStartPos.length); F} d  
for(int i=0;i<nStartPos.length;i++) QORN9SY  
{ ?:Y#Tbi3  
// output.writeLong(nPos); S!{t6'8K  
output.writeLong(fileSplitterFetch.nStartPos); Jl "mL  
output.writeLong(fileSplitterFetch.nEndPos); n8hRaNHl2  
} Zatf9yGD  
output.close(); )NR Q2  
} BA=,7y&;j  
catch(IOException e){e.printStackTrace ();} R<x'l=,D(  
catch(Exception e){e.printStackTrace ();} e:AHVepj{  
} {s3z"OV  
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//读取保存的下载信息（文件指针位置） S60IPya  
private void read_nPos() ?6!]Nl1gr  
{ dSCzx .c  
try{ }oJAB1'k  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); MV=9!{`  
int nCount = input.readInt(); {_U Kttp  
nStartPos = new long[nCount]; I-ag
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nEndPos = new long[nCount]; it2 a  
for(int i=0;i<nStartPos.length;i++) rfw-^`&{  
{ tb?YLxMV  
nStartPos = input.readLong(); tDDy]==E  
nEndPos = input.readLong(); Il`tNr  
} U=8@@yE  
input.close(); i*eAdIi  
} 4'p=p#o  
catch(IOException e){e.printStackTrace ();} )fdE6  
catch(Exception e){e.printStackTrace ();} *;|`E(  
} 0hZ1rqq8C  
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private void processErrorCode(int nErrorCode) *1@:'rJ  
{ { BEo &  
System.err.println("Error Code : " + nErrorCode); C!C|\$)-  
} ",>H(wJ8  
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u =gt<1U  
//停止文件下载 t4K~cK  
public void siteStop() 'lZ.j&  
{ dC}`IR  
bStop = true; /=?ETth @  
for(int i=0;i<nStartPos.length;i++) +%\oO/4Fs  
fileSplitterFetch.splitterStop(); 8j1ekv  
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} -6sW6;Q  
} Y\v-,xPm  
//负责部分文件的抓取 @DC)]C2  
**FileSplitterFetch.java k n8N,,+  
*/ m+itno  
package NetFox; X bkb5EkA  
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import java.io.*; }1-I[q6  
import java.net.*; V[a[i>,Z  
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@ \2#Dpr  
public class FileSplitterFetch extends Thread { amQz^
^  
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String sURL; //File URL  uIMe  
long nStartPos; //File Snippet Start Position ~2u\  
long nEndPos; //File Snippet End Position buk=p-oi  
int nThreadID; //Thread's ID l2
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boolean bDownOver = false; //Downing is over `:M^8SYrL  
boolean bStop = false; //Stop identical "8V{5e!%j'  
FileAccessI fileAccessI = null; //File Access interface V,%L~dI  
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}jSj+*  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException u&QKwD Uh  
{ ngi<v6i  
this.sURL = sURL; e~v(eK_  
this.nStartPos = nStart; dRvin[R8  
this.nEndPos = nEnd; y33~HsOJ  
nThreadID = id; + E"[  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 bXM/2Z?6  
} }jF+`!*
!  
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public void run() u1K\@jlw  
{ ^Jp*B;  
while(nStartPos < nEndPos && !bStop) 0"[`>K~7a8  
{ *Dr5O9Y  
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try{ M,:Bl}  
URL url = new URL(sURL); 5|$a =UIR  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); wb"RB A9  
httpConnection.setRequestProperty("User-Agent","NetFox"); LZ
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String sProperty = "bytes="+nStartPos+"-"; f"&Xr!b.h  
httpConnection.setRequestProperty("RANGE",sProperty); /&ygiH{^  
Utility.log(sProperty); ;mAhY  
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InputStream input = httpConnection.getInputStream(); UEzi*"-v2  
//logResponseHead(httpConnection); !d9AG|  
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byte[] b = new byte[1024]; &d`^E6#  
int nRead; 3]E(mRX  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) xk~Nmb}  
{ '4;6u]d)2  
nStartPos += fileAccessI.write(b,0,nRead); -pTI?  
//if(nThreadID == 1) )"O{D`uX  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 6&2LWaWMo$  
} +_HdX w#  
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Utility.log("Thread " + nThreadID + " is over!"); 7y*ZXT]f  
bDownOver = true; ,=[*Lo>O  
//nPos = fileAccessI.write (b,0,nRead); $R{8z-,Q  
} A~-#@Z  
catch(Exception e){e.printStackTrace ();} B94 &elu  
} dGgP_S  
} Gg0#H^s( (  
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//打印回应的头信息 |k-
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public void logResponseHead(HttpURLConnection con) YT2'!R 1  
{ 1
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for(int i=1;;i++) rcbP$tvz  
{ w.kCBDL  
String header=con.getHeaderFieldKey(i); heD,&OX  
if(header!=null) [^PCm Z6n  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); @Hr+/52B  
Utility.log(header+" : "+con.getHeaderField(header)); 7S2C/f  
else c8'Cq7  
break; J l7z|QS
 
} =L0fZf  
} fU*C/ d3  
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public void splitterStop() 6GOcI#C9C  
{ V;9 }7mw  
bStop = true; Ht=$] Px  
} J^H=i)A  
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} j.c8}r&  
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/* {tzxA_  
**FileAccess.java 8@7AE"  
*//文件访问(定位，写) q9}2  
package NetFox; shi Hy*(v  
import java.io.*;
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public class FileAccessI implements Serializable{ {Jx7_T&  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 P%GkcV  
RandomAccessFile oSavedFile; %RFYm  
long nPos; ch,|1}bi  
.S vyj  
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public FileAccessI() throws IOException WV_`1hZX  
{ 52<~K  
this("",0); {^&k!H2  
} ;mJkqbVol  
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public FileAccessI(String sName,long nPos) throws IOException G\/IM  
{ nu 7lh6o=  
oSavedFile = new RandomAccessFile(sName,"rw"); Lpm?#g uR  
this.nPos = nPos; b:B[3|  
oSavedFile.seek(nPos); T]2U fi.  
} U1^l+G^,~  
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!
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public synchronized int write(byte[] b,int nStart,int nLen) tBl#o ^  
{ /VtlG+dLl  
int n = -1; w4OW4J#  
try{ UA0tFeH  
oSavedFile.write(b,nStart,nLen); YmCbxYa7  
n = nLen; 4_< nQ9K  
} 4[
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catch(IOException e) <$C<Ba?;?  
{ !1-&Y'+  
e.printStackTrace (); V [4n'LcE  
} FU]4oKx  
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return n; $n*%v85  
} 9[f%;WaS  
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} zv9MHC &  
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& >b+loF  
/* Riq|w+Q  
**SiteInfoBean.java xK!DtR
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*/ E(/ sXji!  
package NetFox; 104!!m  
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public class SiteInfoBean { iwkJ~(5z  
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7%opzdS#  
private String sSiteURL; //Site's URL z"av|(?d  
private String sFilePath; //Saved File's Path d qpgf@  
private String sFileName; //Saved File's Name 0:PSt_33F  
private int nSplitter; //Count of Splited Downloading File w7ZG oh(  
3*2I$e!Jt  
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public SiteInfoBean() W2n*bNI  
{//nSplitter的缺省值为5 [edH%S}\  
//default value of nSplitter is 5 r+TK5|ke  
this("","","",5); aL 8Gnqf2  
} ;&7,73!  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 8qmkn
JC  
{ (7ijt  
sSiteURL= sURL; mLULd}g/o  
sFilePath = sPath; 4n4j=x]@  
sFileName = sName; OT%V{hD  
this.nSplitter = nSpiltter; :r^klJ(m  
9^p32G  
@jKDj]\  
} ,N0uR@GN  
)8bFGX7|  
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public String getSSiteURL() 'FqEB]gu  
{ 5Fr;  
return sSiteURL; A~XOK;sB  
} >.LgsMRIKi  
RCQAtBd  
 /+N|X  
public void setSSiteURL(String value) >.n;mk  
{ ennR@pg  
sSiteURL = value; ?Oqzd$
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} V 1*Ad  
44Q9*."  
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public String getSFilePath() ki`8(u6l  
{ H)`@2~Y  
return sFilePath; yz8-&4YRNd  
} J2'W =r_#  
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public void setSFilePath(String value) {&0mK"z_  
{ 6SV7\,2M  
sFilePath = value; k*O
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} %`
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/Ht/F)&P  
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public String getSFileName() @~s~/[  
{ h)^dB,~  
return sFileName; RA}U#D:$i  
} wLpkUa  
}$<^wt  
k)|'JDm  
public void setSFileName(String value) ZWFG?8lJ  
{ #n=A)#'my  
sFileName = value; [f=.!\0\  
} MSK'2+1T@g  
})KJ60B  
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public int getNSplitter() di--:h/  
{ ,TEuM|  
return nSplitter; @W#fui<<}Y  
} ENO? ;  
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public void setNSplitter(int nCount) !O 4<I_EY{  
{ >dyhox2*"  
nSplitter = nCount; eN2dy-0  
} G l_\Vy  
} oPCrD.s  
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/*  oHOW5  
**Utility.java Q!YF!WoBX  
*/ 0r0c|*[+4z  
package NetFox; \QliHm!  
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public class Utility { <{E;s)hD?  
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w2 /* `YO  
public Utility() g})6V  
{ '!Hhd![\=|  
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} ,.[.SU#V  
P`p6J8}4  
//线程睡眠 vc )9Re$  
public static void sleep(int nSecond) Cca6L9%  
{ `b#/[3  
try{ `'*F1F  
Thread.sleep(nSecond); 2H[=lY  
} D!X>O}
  
catch(Exception e) "Ys_ \  
{ M8\G>0Hc6  
e.printStackTrace (); I<c@uXXV;!  
} kmmL>fCV"M  
} "|F.'qZrm  
xy$vYDAFw  
//日志 PP!l  
public static void log(String sMsg) ,wEM Jh  
{
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System.err.println(sMsg); 1po"gVot  
} "fRlEO[9  
^CfM|L8>  
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public static void log(int sMsg) *C5:#A0  
{ F='Xj@&O  
System.err.println(sMsg); ;&K3[;a  
} #D= tX  
} P\,F1N_?r  
v$[ @]`  
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/* EW ~*@H  
**TestMethod.java |VTWw<{LX  
*/ V/`#B$6  
package NetFox; l{nB.m2  
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=]!8:I?C<  
public class TestMethod { ,D:iQDG^  
$/NGNkl[  
C]yvK}  
public TestMethod() kSLSxfR  
{ ///xx/weblogic60b2_win.exe Pbc`LN/s|  
try{ L.SDMz  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); iSOD&J_  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); UVc>i9,0  
SiteFileFetch fileFetch = new SiteFileFetch(bean); PZKbnu  
fileFetch.start(); [Xs}FJ  
} WH{cJ7wCL  
catch(Exception e){e.printStackTrace ();} 
\#uqD\DE  
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} 5JQd)[Im  
g@$0FY{Q  
bq c;.4$  
public static void main(String[] args) /Lq;w'|I  
{ x%b]ea  
new TestMethod(); b%=1"&JI:  
} 4aj[5fhb-  
} t9-_a5>E\}  
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