http断点续传简单实现（java)

/* H gNUr5p  
**SiteFileFetch.java bq[Q  
*/ <?qmB}Y  
package NetFox; J-?\,N1R7  
import java.io.*; N>ct`a)BD/  
import java.net.*; 
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-#gb {vj  
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public class SiteFileFetch extends Thread { {K3\S 0L  
dN |w;|M  
//ZB B,[@  
SiteInfoBean siteInfoBean = null; //文件信息Bean GeHDc[7  
long[] nStartPos; //开始位置 -&,NM  
long[] nEndPos; //结束位置 aE#ZTc=  
FileSplitterFetch[] fileSplitterFetch; //子线程对象  h*%T2  
long nFileLength; //文件长度 7U.g4x|<  
boolean bFirst = true; //是否第一次取文件 N%r}0  
boolean bStop = false; //停止标志 7=QV^G  
File tmpFile; //文件下载的临时信息 D4'XBXmb  
DataOutputStream output; //输出到文件的输出流 f!LZT!y  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） :WA o{|&  
public SiteFileFetch(SiteInfoBean bean) throws IOException 'R]Z9h  
{ mnmwO(.  
siteInfoBean = bean; oN `tZ;a  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); #mkr]K8A4  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); m qw!C  
if(tmpFile.exists ()) lmmyDg1R  
{ [7I|8
  
bFirst = false; )&dhE^ O  
read_nPos(); d}l^yln  
} cC}s
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else @bqCs^U35  
{ ?sS'T7r v  
nStartPos = new long[bean.getNSplitter()]; -S,dG|  
nEndPos = new long[bean.getNSplitter()]; ]LSa(7>EU  
} 29qQ3M?  
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} 4uftx1o   
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public void run() rXm!3E6JL  
{ \~?s= LT  
//获得文件长度 (B$FX<K3  
//分割文件 4l$8lYi  
//实例FileSplitterFetch _-!
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//启动FileSplitterFetch线程 FBY~Z$o0.  
//等待子线程返回 ]@8=e'V  
try{ vy#c(:UQR  
if(bFirst) X^.r@tT  
{ ;XtDz  
nFileLength = getFileSize(); WX=+\`NyJ(  
if(nFileLength == -1) \!^o<$s.G  
{ ?x[>g!r  
System.err.println("File Length is not known!"); n9J>yud|  
} >u/yp[Ky  
else if(nFileLength == -2) nb|MHtPX  
{ Q-au)R,  
System.err.println("File is not access!"); ^CE:?>a$  
} cq=R  
else C=b5[, UCB  
{ mY AFruN  
for(int i=0;i<nStartPos.length;i++) b gDDys  
{ *7vPU:Q[  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); #rC/y0niH  
} +]e4c;`ko}  
for(int i=0;i<nEndPos.length-1;i++) Hb$q}1+y  
{ wS^-o  
nEndPos = nStartPos[i+1]; }dR*bG  
} MmK\|CtV  
nEndPos[nEndPos.length-1] = nFileLength; }rQ*!2Y?  
} &p%ctg  
} Wm,,OioK  
4HHf3j!5  
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//启动子线程 Fi`:G}   
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; eo80L  
for(int i=0;i<nStartPos.length;i++) (BGipX4  
{ BY d3rI  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), >6dgf
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), aF=VJ+5  
nStartPos,nEndPos,i); o MAK[$k;  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); =ht@7z8QM  
fileSplitterFetch.start(); k$2Y)   
} zN:752d^+r  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), +W1rm$Q  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); &Xav$6+Z1J  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Ll`apKr  
nEndPos = " + nFileLength); $d=lDN  
// fileSplitterFetch[nPos.length-1].start(); zW _'sC  
YH>n{o;- ?  
tc',c},h~,  
//等待子线程结束 k);!H+  
//int count = 0; 3YRzBf:h  
//是否结束while循环 r__M1 !3  
boolean breakWhile = false; %Fv)$ :b  
#?*jdN:  
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while(!bStop) +x2xQ8#|~~  
{ P:vy  
write_nPos(); O+N-x8W{  
Utility.sleep(500); <gy'@w?  
breakWhile = true; 0d2%CsMS"D  
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for(int i=0;i<nStartPos.length;i++) KOQTvJ_#  
{ Bz{ g4!ku  
if(!fileSplitterFetch.bDownOver) /b|sv$BN  
{ xpk|?/6  
breakWhile = false; {;zPW!G  
break; ||4Dtg K  
} 7`}z7nk  
} P33E\O  
if(breakWhile) kYAvzuGRb  
break; nGVqVSxKT  
+9X[gef8  
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//count++; Fk(5y)  
//if(count>4) [;I8ZVE  
// siteStop(); gg(U}L ]:  
} #<o#kJL  
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System.err.println("文件下载结束！"); 66*o2D\Q*G  
} {E/TC%  
catch(Exception e){e.printStackTrace ();} kXr%73s  
} ^XM;D/Gp~  
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//获得文件长度 Q
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public long getFileSize() lu_Gr=#O  
{ DtZm|~)a  
int nFileLength = -1; g&>Hy!v,  
try{ Eg*3**gTO  
URL url = new URL(siteInfoBean.getSSiteURL());  Z-@}~#E  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); !UTJ) &  
httpConnection.setRequestProperty("User-Agent","NetFox"); >$DqG$D  
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int responseCode=httpConnection.getResponseCode(); +$t%L  
if(responseCode>=400) eXK`%'  
{ 9K|lU:,  
processErrorCode(responseCode); }U9jsm  
return -2; //-2 represent access is error N6;Z\\&0^q  
} j,XKu5w)Oi  
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String sHeader;
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for(int i=1;;i++) TXcKuo=  
{ l'QR2r7&.  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); TeJ `sJ  
//Utility.log(in.readLine()); iC]lO  
sHeader=httpConnection.getHeaderFieldKey(i); w>uZ$/  
if(sHeader!=null) >{a,]q*  
{ )*
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if(sHeader.equals("Content-Length")) =]e^8;e9  
{ +pvJ?"J  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); M>@R=f  
break; W1Qc1T8  
} $4 Uy3C+6  
} !\1W*6U8;  
else Oq6n.:8g"  
break; T;@>O^  
} ]'(7T#  
} tHbPd.^  
catch(IOException e){e.printStackTrace ();} 9eiBj  
catch(Exception e){e.printStackTrace ();} l,wN@Nk  
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Utility.log(nFileLength); G:`Jrh  
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return nFileLength; \F~Cbj+'Nu  
} G4' U;  
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//保存下载信息（文件指针位置） 9Z'eBp  
private void write_nPos() X vMG09  
{ PU5mz.&0'  
try{ A@(h!Cq  
output = new DataOutputStream(new FileOutputStream(tmpFile)); T+RI8.#o  
output.writeInt(nStartPos.length); '*u;:[73  
for(int i=0;i<nStartPos.length;i++) \_nmfTr
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{ yPYJc  
// output.writeLong(nPos); ?4e6w  
output.writeLong(fileSplitterFetch.nStartPos); #Hi]&)p_  
output.writeLong(fileSplitterFetch.nEndPos); JWHt|zBg  
} 3^>a TU<Z  
output.close(); od*Z$Hb>'  
} vN:[  
catch(IOException e){e.printStackTrace ();} )C]&ui~1  
catch(Exception e){e.printStackTrace ();} xY2_
*#{.  
} ROS"VV<  
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//读取保存的下载信息（文件指针位置） h6y4Ii  
private void read_nPos() f\|?_k]  
{ {@__%=`CCS  
try{ J+jmSK%z  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Cfo 8gX*  
int nCount = input.readInt(); Lo5@zNt%W  
nStartPos = new long[nCount]; P
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nEndPos = new long[nCount]; w/5^R  
for(int i=0;i<nStartPos.length;i++) D"4&9"CU  
{ V9u\;5oL  
nStartPos = input.readLong(); 9zYiG3 d  
nEndPos = input.readLong(); NjN?RB/5  
} L8wcH  
input.close(); @[tV_Z%,b  
} 8sIA;r%S  
catch(IOException e){e.printStackTrace ();} AAq=,=:R<  
catch(Exception e){e.printStackTrace ();} F(9 Y/UXH  
} .*-w UBr  
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private void processErrorCode(int nErrorCode) 'z}M[h K]  
{ 68<Z\WP  
System.err.println("Error Code : " + nErrorCode); ~X<cG=p~u  
} 7[v@*/W@  
!{tiTA  
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//停止文件下载 F4E3c4 81  
public void siteStop() rjHIQC C  
{ uk[< 6oxz  
bStop = true; nIQ&gbfO  
for(int i=0;i<nStartPos.length;i++) 2?- 0
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fileSplitterFetch.splitterStop(); L3GC[$S  
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} x2;i< |  
} .um&6Q=2<  
//负责部分文件的抓取 ^M"z1B]  
**FileSplitterFetch.java bk"k&.C^+  
*/ 15
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package NetFox; M&/aJRBS  
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import java.io.*; ,ah*!Zm.kk  
import java.net.*; k l!?/M  
+6hl@Fm(  
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public class FileSplitterFetch extends Thread { u}}9j&^Xa  
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String sURL; //File URL yvd `nV  
long nStartPos; //File Snippet Start Position #CA%]*l
*F  
long nEndPos; //File Snippet End Position y(nsyA  
int nThreadID; //Thread's ID VP%i1|XZJ  
boolean bDownOver = false; //Downing is over %7v@n+Q  
boolean bStop = false; //Stop identical kg: uGP9  
FileAccessI fileAccessI = null; //File Access interface Fu4EEi  
5rmlAq  
t'Eb#Nup3  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException S6T!qH{6  
{ 7AO3-; l]  
this.sURL = sURL; ]oeuIRyQ  
this.nStartPos = nStart; hB7pR"P  
this.nEndPos = nEnd; ^0~c7`k`V  
nThreadID = id; 'ZC}9=_g  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 |ck ZyDA  
} UV']NHh  
lH)em.#  
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public void run() h;%i/feFg  
{ :'y{dbKp"  
while(nStartPos < nEndPos && !bStop) <r<Dmn|\a  
{ j!x<QNNX  
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try{ J1tzH
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URL url = new URL(sURL); ) \-96 xd  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); cophAP  
httpConnection.setRequestProperty("User-Agent","NetFox"); HkdN=q  
String sProperty = "bytes="+nStartPos+"-"; au~]  
httpConnection.setRequestProperty("RANGE",sProperty); -VWCD,c  
Utility.log(sProperty); @A2/@]HBm  
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InputStream input = httpConnection.getInputStream(); Y9i9Uc.]  
//logResponseHead(httpConnection); 7|QGY7Tf  
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byte[] b = new byte[1024]; j|[(*i%7|  
int nRead; 4ZI!,lv*  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) tw'hh@7-Y  
{ ?7yQ&p  
nStartPos += fileAccessI.write(b,0,nRead); jby~AJf%  
//if(nThreadID == 1) OL=ET)Y  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 8:HSPDU.  
} 9Hh~ nR?  
X`yNR;>  
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Utility.log("Thread " + nThreadID + " is over!"); 3(!/["@7  
bDownOver = true; IXZ(]&we
 
//nPos = fileAccessI.write (b,0,nRead); Vk-W8[W 7  
} ~reQV6oQua  
catch(Exception e){e.printStackTrace ();} -F"d0a,  
} / R_ u\?k(  
} ;TL(w7vK  
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//打印回应的头信息 Q[J [=  
public void logResponseHead(HttpURLConnection con) _0,"vFdj  
{ 8 7RHA $?  
for(int i=1;;i++) :be:-b%K  
{ (R_CUH  
String header=con.getHeaderFieldKey(i); ?R;nL{  
if(header!=null) zmf"I[)  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); /Hv*K&}M  
Utility.log(header+" : "+con.getHeaderField(header)); ,b<9?PM  
else of8mwnZR  
break; <ROpuY\!l  
} cMDRWh  
} Ia=_78MgZ  
<S]KaDu^  
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public void splitterStop() HEBqv+bG  
{ Z)m
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bStop = true; v9%nau4  
} /Q?~Q0{)es  
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} i?F[||O"$  
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/* XtCoX\da  
**FileAccess.java %_R$K#T^,  
*//文件访问(定位，写) *(k%MTG  
package NetFox; i"L}!5  
import java.io.*; }0QN[$H!  
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public class FileAccessI implements Serializable{ !w q4EV  
i90}Xyt  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 @l'G[jN5  
RandomAccessFile oSavedFile; 1Gsw-a;a  
long nPos; !:(C"}5wM  
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public FileAccessI() throws IOException nO~b=q
O  
{ dM Y 0K  
this("",0); <eY%sFq,  
} [s~JceUyX  
zI:(33)  
eUt=n)*`  
public FileAccessI(String sName,long nPos) throws IOException );nz4/V  
{ kI%peb?  
oSavedFile = new RandomAccessFile(sName,"rw"); aD2*.ln><  
this.nPos = nPos; tM)Iir*U#  
oSavedFile.seek(nPos); QU.0Elw  
} ,jy<o+!  
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public synchronized int write(byte[] b,int nStart,int nLen) X~lZOVmS  
{ #e/2C  
int n = -1; !\^jt%e&  
try{ 3:lDL2  
oSavedFile.write(b,nStart,nLen); 9`B0fv Q&  
n = nLen; XYe~G@Q Z  
} ,yICNtP  
catch(IOException e) RlrZxmPV>O  
{ id^|\hDR  
e.printStackTrace (); 6 }!Z"  
} v dU%R\  
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return n; h3kaD  
} q +R*Hi  
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} A:eFd]E{(  
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/* L}$z/jo  
**SiteInfoBean.java +{.780|  
*/ }X]\VSF{  
package NetFox; Kq&qE>Ju  

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public class SiteInfoBean { %:3'4;jh%  
?6f7ld5  
03EV%Vc  
private String sSiteURL; //Site's URL |jT2W  
private String sFilePath; //Saved File's Path %x2uP9  
private String sFileName; //Saved File's Name n!G.At'JP  
private int nSplitter; //Count of Splited Downloading File |O-`5_z$r  
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public SiteInfoBean() Q".g.k  
{//nSplitter的缺省值为5 =q+R   
//default value of nSplitter is 5 BFWi(58q  
this("","","",5); WuM C^  
} p&^J=_O  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Z~p!C/B  
{ y<uAp  
sSiteURL= sURL;
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sFilePath = sPath; M+poB+K.  
sFileName = sName; <~{du ?4n  
this.nSplitter = nSpiltter; *%\mZ,s"  
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jvHFFSK  
} uvnI>gv  
r|G
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public String getSSiteURL() zrRFn `B  
{ *}cSE|S%  
return sSiteURL; #f{lC0~vA  
} :+ Jt^ 6  
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public void setSSiteURL(String value) +;Cr];b3  
{ Icx7.Y  
sSiteURL = value; mnjs(x<m  
} u5Up&QE!>q  
0{+.H_f`  
+q{[\#t5  
public String getSFilePath() Vr=OYI'A  
{ PD6_)PXn  
return sFilePath; 6e
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} "AC^ rz~U  
"(`2eXR
n  
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public void setSFilePath(String value) (ChD]PWQ  
{ E.`6oX\L|  
sFilePath = value; !_~UvxM+  
} 5\hd4  
m#e*c[*G  
V`#.7uUP  
public String getSFileName() UDEj[12S  
{ tfYB_N  
return sFileName; bg
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} O_;Dk W  
0;<)\Wt=i9  
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public void setSFileName(String value) ^/@jwZ  
{ w1`QIv  
sFileName = value; $f$|6jM  
} sy/nESZs  
sOBu7!G%  
f>polxB%N  
public int getNSplitter() Kj3?ve~  
{ t"vRc4mf  
return nSplitter; hyg8wI  
} DM{ 4@*]  
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public void setNSplitter(int nCount) -!e7L>w  
{ 2`?!+")  
nSplitter = nCount; 0w=R_C)
s  
} //f  
} t2>fmQIQ  
7Nzbz3  
% 0T+t.  
/* k;ZxY"^  
**Utility.java 4x;_AN  
*/ ABh&X+YD  
package NetFox; !w39FfU{  
p{D4"Qn+P9  
~P.I<  
public class Utility { IkPN?N  
k*mt4~KLT8  
7zemr>sIh  
public Utility() 5jB*fIz  
{ UUc8*yU)  
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}
>&:NFq-  
)%d*3\Tsd  
//线程睡眠 ntVS:F
 
public static void sleep(int nSecond) vBcq_sbo  
{ 2`GOJ,$  
try{ eE GfM0  
Thread.sleep(nSecond); vy9 w$ls  
} jszK7$]^  
catch(Exception e) [ic87
0_  
{ O@V%Cu  
e.printStackTrace (); AlXNg!j;5K  
} J aTp}#  
} "A$!, PX6  
n+;6=1d7ZW  
//日志 'Ft0Ry<OL  
public static void log(String sMsg) vw,rF`LjZ  
{ "VG+1r+]4  
System.err.println(sMsg); %Dg0fL  
} @Fp_^5  
}7E^ZZ]f  
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public static void log(int sMsg) o1cErI&q"  
{ ~Wo)?q8UY,  
System.err.println(sMsg); aFz5leD  
} 5,-U.B}  
} a2'^8;U*_  
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aE;le{|!({  
/* scLn=  
**TestMethod.java }X*Riu7gk  
*/ li~d?>  
package NetFox; I M-L'9  
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public class TestMethod { nD5 gP  
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tg]x0#@s  
public TestMethod() 26&'X+n&  
{ ///xx/weblogic60b2_win.exe +_XzmjnDd  
try{ ?qCK7$j  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); h3LE>}6D  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); <:SZAAoIV  
SiteFileFetch fileFetch = new SiteFileFetch(bean); &wD;SMr<  
fileFetch.start(); h 3]wL.V  
} sl]_M  
catch(Exception e){e.printStackTrace ();} +s- lCz  
}:X*7 n(&  
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} Ec
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,lZB96r0  
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public static void main(String[] args) _%5Ro6  
{ ]]Cb$$Td  
new TestMethod();  GB$;n?  
} GGnpjwXeH  
} \"X!2  
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