http断点续传简单实现（java)

/* Rpou.RrXR7  
**SiteFileFetch.java c^W \0  
*/ C~q&  
package NetFox; 9Pjw<xt  
import java.io.*; |N%#;7  
import java.net.*; 1qN+AT  

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public class SiteFileFetch extends Thread { ty-erdsP  
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SiteInfoBean siteInfoBean = null; //文件信息Bean Rt3/dw(p  
long[] nStartPos; //开始位置 #J|DW C!#d  
long[] nEndPos; //结束位置 !rPU5y*  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 u~\l~v^mj  
long nFileLength; //文件长度 @; 0t+  
boolean bFirst = true; //是否第一次取文件 ~xakz BE  
boolean bStop = false; //停止标志 1b`WzoJgH  
File tmpFile; //文件下载的临时信息 L2`a| T=  
DataOutputStream output; //输出到文件的输出流 7>!Rg~M  
l2 mO{'|C  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） dH_g:ocA  
public SiteFileFetch(SiteInfoBean bean) throws IOException 3}gf%U]L  
{ vq-#%o  
siteInfoBean = bean; CCp&+LRvR  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ql2O%B.6?  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); *Fu;sR2y%:  
if(tmpFile.exists ()) la{Iqm{i  
{ GPLq$^AH  
bFirst = false; >A ?{cbJ  
read_nPos(); &N:`Rler  
} NhF<2[mt  
else {/}p"(
^  
{ ~LSD\+  
nStartPos = new long[bean.getNSplitter()]; iiD}2yb  
nEndPos = new long[bean.getNSplitter()]; ZxU3)`O  
} *G(ZRj@33  
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} CA5q(
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public void run() 'Z82+uU%  
{ Vk?US&1q}  
//获得文件长度 P-)`FB  
//分割文件 }4XXNYH  
//实例FileSplitterFetch _(0GAz%9  
//启动FileSplitterFetch线程 vuO~
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//等待子线程返回 =5u;\b>*  
try{ (8jQdbZU
 
if(bFirst) st-I7K\v  
{ f\h|Z*Bv  
nFileLength = getFileSize(); m(p0)X),_i  
if(nFileLength == -1) cC7&]2X +f  
{ J8#3?Lp  
System.err.println("File Length is not known!"); Dx>~^ ^<  
} 3Q~zli:  
else if(nFileLength == -2) +?bjP6w_g  
{ z,IUCNgM  
System.err.println("File is not access!"); H:!pFj  
} 4$MV]ldUI  
else ,@r 0-gL  
{ 'q, L*  
for(int i=0;i<nStartPos.length;i++) !B:wzb_  
{ +MvO+\/  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Rn5{s3?F~2  
} YW'l),Z  
for(int i=0;i<nEndPos.length-1;i++) {LoNp0i1a  
{ *4?%Y8;bF6  
nEndPos = nStartPos[i+1]; 5%;=(Oig  
} N5|wBm>m  
nEndPos[nEndPos.length-1] = nFileLength; \>p\~[cxt  
} |[/'W7TV%?  
} r9!,cs  

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//启动子线程 IXof-I%8  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; @lTd,V5f  
for(int i=0;i<nStartPos.length;i++) jV~+=(w)  
{ bm#/ KT_8  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Yrmd hSY  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), PIZK*Lop  
nStartPos,nEndPos,i); KAR **Mp+  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); #s
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fileSplitterFetch.start(); JYO("f  
} :BpXi|n;  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), }E&48$0h  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); MVOWJaT(Aq  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", -i*]Sgese  
nEndPos = " + nFileLength); /j;HM[  
// fileSplitterFetch[nPos.length-1].start(); erd
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#v}pn2g%>  
+5qY*$dn  
//等待子线程结束 uE-|]QQo  
//int count = 0; ~U<=SyZYo  
//是否结束while循环 WIYWql>*  
boolean breakWhile = false; dj5@9X  
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while(!bStop) ]y~"M  
{ H.#zbKj  
write_nPos(); +!eh\.u|]  
Utility.sleep(500); ;kR+jC(  
breakWhile = true; pz,iQUs_o  
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 wjfc9z  
for(int i=0;i<nStartPos.length;i++) VX]Ud\(  
{ -E>LB\[t)  
if(!fileSplitterFetch.bDownOver) `tH:oP0=  
{ A!IZIT5)m  
breakWhile = false; E5 uk<e_  
break; :@K~>^+U  
} $_Q]3"U  
} Fb<fQIa  
if(breakWhile) gRg8D{  
break; Q1[EiM3  
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.  
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//count++; UIK4]cYC'  
//if(count>4) iPdR;O'  
// siteStop(); "V{v*Aei0  
} Bnh*;J0  
RKD$'UWX  
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System.err.println("文件下载结束！"); |)+45e  
} bEli!N$
  
catch(Exception e){e.printStackTrace ();} #@}wl  
} \vF*n Z5/  
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rHJtNN8$k  
//获得文件长度 (Z?g^kjq)  
public long getFileSize() Dgm"1+  
{ lc\%7
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int nFileLength = -1; b0uWUI(=  
try{ uy8mhB+]  
URL url = new URL(siteInfoBean.getSSiteURL()); !m6=Us  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); s(cC;  
httpConnection.setRequestProperty("User-Agent","NetFox"); W ![*0pL  
?$~5ti#\  
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int responseCode=httpConnection.getResponseCode(); 5;X3{$y  
if(responseCode>=400) qv)%)n  
{ g [c^7  
processErrorCode(responseCode); {"mb)zr  
return -2; //-2 represent access is error >N-l2?rE  
} ".sRi  
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String sHeader; `Tc"a_p9t  
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for(int i=1;;i++) To =JE}jzo  
{ #D .hZ=!  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Oj#/R?%,X  
//Utility.log(in.readLine()); e|eWV{Dsz  
sHeader=httpConnection.getHeaderFieldKey(i); $Qcr8~+a  
if(sHeader!=null) q*7:L  
{ z,c=."<z  
if(sHeader.equals("Content-Length")) H-t"Z}  
{ FZx.Yuv  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); q" @%WK  
break; SY$%)(c8kL  
} %OJq(}  
} MQq!<?/  
else 2 sK\.yS  
break; <8BNqbX  
} %:yVjb,Yf  
} CtE <9?  
catch(IOException e){e.printStackTrace ();}  J7p?9  
catch(Exception e){e.printStackTrace ();} Vw+RRi(  
+k\cmDcb  
}TRVCF1  
Utility.log(nFileLength); ][B>`gC-  
b]
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return nFileLength; 5Yr$tl\k  
} bFsJqA.A  
}xpo@(e  
RKb (  
//保存下载信息（文件指针位置） |vgYi  
private void write_nPos() Zb$P`~(%  
{ 7uq^TO>9f  
try{ Ny G?^  
output = new DataOutputStream(new FileOutputStream(tmpFile)); #]z_pp:  
output.writeInt(nStartPos.length); \CrWKBL  
for(int i=0;i<nStartPos.length;i++) =`.OKUAn  
{ wW|[Im&  
// output.writeLong(nPos); Xd5uF/w  
output.writeLong(fileSplitterFetch.nStartPos); M`H@ % M  
output.writeLong(fileSplitterFetch.nEndPos); tC\(H=ecP  
} \-CL}Z}S  
output.close(); H0-v^H>^  
} La r9}nx0  
catch(IOException e){e.printStackTrace ();} SHRn$<  
catch(Exception e){e.printStackTrace ();} WB3YN+Xl3  
} Lc_cB`  
);d"gv(]D  
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//读取保存的下载信息（文件指针位置） aRcVoOq  
private void read_nPos() 0gH;y+\=*  
{ e@{Rlz  
try{ Y?\PU{O  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); DhN<e7c`  
int nCount = input.readInt(); K[l5=)G0L  
nStartPos = new long[nCount]; 3M5wF6nY[[  
nEndPos = new long[nCount];  I}u&iV`  
for(int i=0;i<nStartPos.length;i++) qkBCI,X_Y  
{ GuKiNYI_  
nStartPos = input.readLong(); `NCH^)  
nEndPos = input.readLong(); -ju}I  
} i=jYl  
input.close(); @.} @K  
} m.Ki4NUm  
catch(IOException e){e.printStackTrace ();} lQ#='Jqfp  
catch(Exception e){e.printStackTrace ();} !7Nz_d~n  
} 23/;W|   
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private void processErrorCode(int nErrorCode) T9bUt|  
{ lsKQZ@LN`  
System.err.println("Error Code : " + nErrorCode); i!yE#z
ew  
} G$VE o8Blb  
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//停止文件下载 f0+vk'Z  
public void siteStop()  NR98]X  
{ :H>0/^Mg0  
bStop = true; w+iIay  
for(int i=0;i<nStartPos.length;i++) ^y[- e9O|  
fileSplitterFetch.splitterStop(); .1jeD.l  
, FR/X/8  
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} aole`PD,l  
} m^>v~Q~~  
//负责部分文件的抓取 Pxf/*z  
**FileSplitterFetch.java Suy +XHV  
*/ RKy!=#;17  
package NetFox; y#i` i  
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import java.io.*; Xo3@-D_c!c  
import java.net.*; &/(JIWc1su  
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public class FileSplitterFetch extends Thread { t"P:}ps{?  
+aN"*//i  
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String sURL; //File URL z/wwe\ a5  
long nStartPos; //File Snippet Start Position 3L9@ELY4  
long nEndPos; //File Snippet End Position /6:qmh2  
int nThreadID; //Thread's ID p{AX"|QM"  
boolean bDownOver = false; //Downing is over e'r-o~1eN  
boolean bStop = false; //Stop identical !vq|*8  
FileAccessI fileAccessI = null; //File Access interface '<xV]k|v  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Hz j%G>  
{ cVli^*se  
this.sURL = sURL; GOD{?#
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this.nStartPos = nStart; [F 24xC+  
this.nEndPos = nEnd; g0#w 4rGF)  
nThreadID = id; i?f;C_w  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 !V-(K_\t  
} * 'Bu-
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public void run() 7G%:ckg  
{ [DvQk?,t  
while(nStartPos < nEndPos && !bStop) =3dd1n;8>  
{ wH+| &C  
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try{ k|^`0~E  
URL url = new URL(sURL); Z29aRi  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); B`:l;<&jX  
httpConnection.setRequestProperty("User-Agent","NetFox"); f o idneus  
String sProperty = "bytes="+nStartPos+"-"; TQth"Cv2:  
httpConnection.setRequestProperty("RANGE",sProperty); cp6I]#X  
Utility.log(sProperty); \-
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InputStream input = httpConnection.getInputStream(); sfk;c#K  
//logResponseHead(httpConnection); *!ecb1U5  
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>4J(\'}m|  
byte[] b = new byte[1024]; xtut S  
int nRead; xqfIm%9i}  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) A2SD
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{ L~C:1VG5  
nStartPos += fileAccessI.write(b,0,nRead); -_= m j  
//if(nThreadID == 1) <u/(7H
 
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Cv[1HO<  
} nPk&/H%5hn  
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Utility.log("Thread " + nThreadID + " is over!"); AWi+xo|  
bDownOver = true; Kl<NAv%j  
//nPos = fileAccessI.write (b,0,nRead); )KOIf{  
} }i J$&CJ  
catch(Exception e){e.printStackTrace ();} tVh"C%Vkr  
} ] !n3j=*  
} Pbt7T Q  
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//打印回应的头信息 '$[%x  
public void logResponseHead(HttpURLConnection con) =|dHD  
{ V>D}z8w7  
for(int i=1;;i++) ,&L}^Up  
{ y
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String header=con.getHeaderFieldKey(i); a'A<'(yv  
if(header!=null) D@kf^1G  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ;=WwJ Np~  
Utility.log(header+" : "+con.getHeaderField(header)); '4CD }  
else C[5dhFZ  
break; ^PUB~P/  
} OY2u,LF9H  
} ]^,!;do  
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@9R78Zra  
public void splitterStop() )S;3WnQ)  
{ txE+A/>i9  
bStop = true; :(@P *"j  
} )_Z^oH ]<  
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} M6GiohI_"P  
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).AMfBQ=;  
/* "Q{l])N  
**FileAccess.java | AiMx2  
*//文件访问(定位，写) t7Mq>rFB  
package NetFox; JKy~'>Q  
import java.io.*; pw`'q(ad  
UmY{2 nzY  
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public class FileAccessI implements Serializable{ Ubgn^+AI  
7D1$cmtH  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 3_`)QYU'  
RandomAccessFile oSavedFile; \0vs93>?  
long nPos; jAU&h@  
hRMya#%-  
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public FileAccessI() throws IOException {e q378d  
{ 9M5W4&  
this("",0); R_\o`v5  
} @DF7j|]tV  
vn!3Z!dm(  
jw`05rw:  
public FileAccessI(String sName,long nPos) throws IOException sG)aw`_j  
{ jOzi89  
oSavedFile = new RandomAccessFile(sName,"rw"); ^bP`Iv  
this.nPos = nPos; y#th&YC_b  
oSavedFile.seek(nPos); 1z4_QZZ.NG  
} -y{(h%6  
pb)kN%  
gS8+S\2
 
public synchronized int write(byte[] b,int nStart,int nLen) %V+"i_{m  
{ - Ry+WS=  
int n = -1; ;<_a ,5\Q  
try{ k61mRO  
oSavedFile.write(b,nStart,nLen); [cco/=c  
n = nLen; lcy<taNu)  
} 3zu6#3^  
catch(IOException e) *ra>Kl0   
{ vbd)L$$20+  
e.printStackTrace (); /'5d0' ,M  
} kD?@nx>  
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return n; JgA{1@h  
} R PoBF~>  
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} AI Kz]J0;  

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/* 'O\
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**SiteInfoBean.java ^i_+ugJX  
*/ W`NF40)  
package NetFox; <oV[[wl  
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public class SiteInfoBean { (CY D]n  
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private String sSiteURL; //Site's URL =QGmJ3  
private String sFilePath; //Saved File's Path N5,LHO  
private String sFileName; //Saved File's Name mC$y*G  
private int nSplitter; //Count of Splited Downloading File y_w  <3  
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public SiteInfoBean() 'Grii,  
{//nSplitter的缺省值为5 ge:a{L  
//default value of nSplitter is 5 &)gc{(4$  
this("","","",5); =y_KL
  
} )GAlj;9A$  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) CbC[aVA=  
{ /e|Lw4$@S  
sSiteURL= sURL; u!5q)>Wt(  
sFilePath = sPath; `[g$EXX  
sFileName = sName; ES AX}uF  
this.nSplitter = nSpiltter; 2xflRks  
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} , ?U)mYhI  
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public String getSSiteURL() ZTV)D  
{ t!*[nfR  
return sSiteURL; ]& ckq  
} lnHY?y7{  
peBHZJ``RX  
#qYgQ<TM!  
public void setSSiteURL(String value) PA ?2K4  
{ <%Nf"p{K  
sSiteURL = value; t(6]j#5   
} }DS%?6}Sy  
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public String getSFilePath() "nCK%w=  
{ n]`]gLF\i  
return sFilePath; #IvKI+"  
} GdI,&|/  
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public void setSFilePath(String value) gBv!E9~l  
{ [,,@>nyD  
sFilePath = value; $"W[e"Q  
} {$hWz(  
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,v K%e>e&  
public String getSFileName() o>C,Db~L/  
{ 2HmK['(  
return sFileName; ch]Q
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} T`":Q1n  
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public void setSFileName(String value) PdqvXc  
{ ?Y3i-jY
  
sFileName = value; Zf3(! a[  
} Ig}hap]G  
5=I({=/>  
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public int getNSplitter() BInSS*L  
{ ?
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return nSplitter; :rQDA=Ps  
} eN.6l2-  
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*6` ^8Y\  
public void setNSplitter(int nCount) jmwN1Se>  
{ tj~r>SRb+  
nSplitter = nCount; pNOE KiJ  
} ~6n|GxR.[  
} PiM(QR  
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/* Awxm[:r>^  
**Utility.java -Yse^(^"s  
*/ mc%. 8i  
package NetFox; n
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public class Utility { ftTD-d  
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public Utility() 5@%Gq)z5  
{ \ Y
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}
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[-VH%OM  
//线程睡眠 j!i*&  
public static void sleep(int nSecond) 3-hcKE  
{ >y#MEN>?  
try{ V'=;M[&  
Thread.sleep(nSecond); x)dLY.'|  
} !AE;s}v)0{  
catch(Exception e) &,%n  
{ JseKqJ?g  
e.printStackTrace (); aUZ?Ue9l>2  
} a5/, O4Q  
} )jgz(\KZ  
#rX^)2  
//日志 "=s}xAM|A  
public static void log(String sMsg) |
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{ Y+Z+Y)K
  
System.err.println(sMsg); tqh)yr;  
} ,\"x#Cc f  
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@
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public static void log(int sMsg) ^UKY1Q.  
{ Q2ne]MI  
System.err.println(sMsg); k{;
?>=FH!  
} mz.,j(Ks-  
} m<3. X"-  
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'+/mt_re=  
/* 9ns( F:  
**TestMethod.java wsB-( 0-  
*/ {l$)X  
package NetFox; A4@z+ebb l  
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drjNK!XL@  
public class TestMethod { 
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9D\E0YG X/  
98R/^\  
public TestMethod() D? %*L  
{ ///xx/weblogic60b2_win.exe W)r|9G8T  
try{ mv:@D  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ;~:Z~8+{c  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ,^c-}`!K  
SiteFileFetch fileFetch = new SiteFileFetch(bean); V=+|]`  
fileFetch.start(); ,)xtl`fc  
} Ne|CWUhO  
catch(Exception e){e.printStackTrace ();} $!9U\Au>2  
A}9^,C$#  
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} 1YMi4.  
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public static void main(String[] args) Xk%eU>d  
{ vo }4N[]Sb  
new TestMethod(); Kn$E{F\  
} <`SA>P  
} 83V\O_7j  
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