http断点续传简单实现（java)

/* e7(iMe  
**SiteFileFetch.java KL8G2"Z  
*/ 2k}" 52  
package NetFox; P@m_tA%  
import java.io.*; )e$}sw{t  
import java.net.*; |(Bc0sgw}  
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public class SiteFileFetch extends Thread { Vg6/1I  
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SiteInfoBean siteInfoBean = null; //文件信息Bean i58&o@.H<u  
long[] nStartPos; //开始位置 VuOZZ7y  
long[] nEndPos; //结束位置 O]>FNsh!  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 J\kGD  
long nFileLength; //文件长度 P9Yw\   
boolean bFirst = true; //是否第一次取文件 Y~P1r]piB  
boolean bStop = false; //停止标志 {
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File tmpFile; //文件下载的临时信息 6z6\-45  
DataOutputStream output; //输出到文件的输出流 s7A3CY]->  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 29xm66  
public SiteFileFetch(SiteInfoBean bean) throws IOException x.+r.cAXH  
{ m+t<<5I[-  
siteInfoBean = bean; F ka^0  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); (9#$za>  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); |L@&plyB-  
if(tmpFile.exists ()) 00?_10x)  
{ aDV~T24  
bFirst = false; oTtJ]`T  
read_nPos(); pf\ Ybbs  
} x:7"/H|  
else Y+,ii$Ce~  
{ }=dUASL  
nStartPos = new long[bean.getNSplitter()]; &%@b;)]J  
nEndPos = new long[bean.getNSplitter()]; "~1{|lj|)  
} Y ,Iv<Hg  
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} H{}Nr 4  
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public void run() Oy,7>vWQI  
{ !O`a
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//获得文件长度 EO&PabZWR  
//分割文件 Ft&ARTsa*  
//实例FileSplitterFetch 7s2 l3  
//启动FileSplitterFetch线程 Y$vobi$  
//等待子线程返回 #-]!;sY>  
try{ :>:F6Db"U  
if(bFirst) FZt a  
{ FZvh]ZX  
nFileLength = getFileSize(); :7WeR0*%  
if(nFileLength == -1) BHNcE*U}@?  
{ b"DV8fdX  
System.err.println("File Length is not known!");
|61W-9;  
} 5f~49(v]  
else if(nFileLength == -2) AYVkJq?  
{ I"=a:q  
System.err.println("File is not access!"); qG]G0|f  
}
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else AHo4% 5  
{ ?M}W;Z  
for(int i=0;i<nStartPos.length;i++) M$jU-;hRH  
{ _d[4EY  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); -4%{Jb-1  
} g< F7UA  
for(int i=0;i<nEndPos.length-1;i++) b1*5#2rs.  
{ C[-M ~yIL  
nEndPos = nStartPos[i+1]; 'lsG?  
} !OCb^y  
nEndPos[nEndPos.length-1] = nFileLength; \CY_nn|&g  
} ujLz<5gKuO  
} 7f$ hg8  
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//启动子线程 0qCx.<"p8#  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; [P3].#"]M=  
for(int i=0;i<nStartPos.length;i++) }akF=/M  
{ aqw;T\GI+~  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), )S8fFV  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), pV^(8!+  
nStartPos,nEndPos,i); &OMe'P  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); e5GJ:2sH  
fileSplitterFetch.start(); 6T qs6*  
} 7)i6L'r  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ;VS\'#{e  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); (lzZ=T  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ",
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nEndPos = " + nFileLength); fz[-pJ5[  
// fileSplitterFetch[nPos.length-1].start(); _Nx#)(
x  
[ r<0[  
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//等待子线程结束 1MPn{#Ff  
//int count = 0; 1v?|n8  
//是否结束while循环 @ptE&
m  
boolean breakWhile = false; MYlPG1X=?  
ta*6xpz-\Q  
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while(!bStop) OgOs9=cE{  
{ k-;A9!^h  
write_nPos(); f]*TIYicc  
Utility.sleep(500); @hG]Gs[,o  
breakWhile = true; ;bMmJ>[l-  
`{B<|W$=  
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for(int i=0;i<nStartPos.length;i++) Qp5Y
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{  j1sgvh]D  
if(!fileSplitterFetch.bDownOver) $Lc-}m9n  
{ }jI=*  
breakWhile = false; 4#fgUlV  
break; }vXf}2C  
} <CIy|&J6  
} @((Y[<  
if(breakWhile) mC,:.d  
break; a9sbB0q-K@  
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//count++; m35$4  
//if(count>4)  (%\tE  
// siteStop(); RHIGNzSz  
} dBG5IOD  
'Cp]Q@]\  
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System.err.println("文件下载结束！"); EqjaD/6Y`  
} a^>e|Eq|  
catch(Exception e){e.printStackTrace ();} H7}@56  
} .zQ'}H1.C  
'k1vV  
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//获得文件长度 .}4^b\  
public long getFileSize() 4r-CF#o  
{ .1@8rVp7  
int nFileLength = -1; TEEt]R-y  
try{ {*NM~yQ  
URL url = new URL(siteInfoBean.getSSiteURL()); upc-Qvk  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); +W}dO#  
httpConnection.setRequestProperty("User-Agent","NetFox"); dSkx*#FEE  
-nL!#R{e  
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int responseCode=httpConnection.getResponseCode(); !=B=1th4  
if(responseCode>=400) S4!}7NOh  
{ #sJL"GB  
processErrorCode(responseCode); D3.$Vl,.  
return -2; //-2 represent access is error G1?m}{D)  
} 7+c}D>/`:  
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String sHeader; hVLVMqd  
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for(int i=1;;i++) v9K=\ j  
{ FC&841F  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); }u&,;]  
//Utility.log(in.readLine()); 8oxYgj&~X  
sHeader=httpConnection.getHeaderFieldKey(i); <3WaFi u  
if(sHeader!=null) rT/4w#_3  
{ U3rpmml  
if(sHeader.equals("Content-Length")) RGC DC*
\  
{ L8.u7(-#  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 032PR;]  
break; A` )A=L  
} _uQxrB"9  
} qQ^bUpk0  
else tFrNnbmlQ  
break; \O G`+"|L  
} _WB*ArR  
} CWx_9b zk  
catch(IOException e){e.printStackTrace ();} dxk~  
catch(Exception e){e.printStackTrace ();} gg+!e#-X  
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Utility.log(nFileLength); ^sb+|b  
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return nFileLength; &l;wb.%ijW  
} Bm:N@wg  
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//保存下载信息（文件指针位置） /vrjg)fer  
private void write_nPos() ki<4G  
{ }:9UI  
try{ yTpvKCC  
output = new DataOutputStream(new FileOutputStream(tmpFile)); <52)  
output.writeInt(nStartPos.length); -l i71.M  
for(int i=0;i<nStartPos.length;i++) 3uJ>:,~r  
{ =cKrp'  
// output.writeLong(nPos); T.B}k`$  
output.writeLong(fileSplitterFetch.nStartPos); *R8qnvE\()  
output.writeLong(fileSplitterFetch.nEndPos); M7. fz"M  
} 1Uf8ef1,  
output.close(); <cNg_ZZ;8  
} gVU&Yl~/^  
catch(IOException e){e.printStackTrace ();} oV,lEXz  
catch(Exception e){e.printStackTrace ();} #1VejeTi  
} jB-wJNP/  
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//读取保存的下载信息（文件指针位置） l>{+X )  
private void read_nPos() (rB?
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{ g'nN#O  
try{ wfY]J
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DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); y_A7CG"^  
int nCount = input.readInt(); NI)q<@ju
 
nStartPos = new long[nCount]; a,~}G'U  
nEndPos = new long[nCount]; y - Ge"mY  
for(int i=0;i<nStartPos.length;i++) _;8+L\  
{ o:nh3K/YJ  
nStartPos = input.readLong(); NUb:5tL  
nEndPos = input.readLong(); 0{zA6Xu  
} +E8}5pDt  
input.close(); e_z"<yq  
} ^e4y:#Nu  
catch(IOException e){e.printStackTrace ();} IP-}J$$1  
catch(Exception e){e.printStackTrace ();} jSMs<ox  
} =[x @BzH  
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private void processErrorCode(int nErrorCode) = }6l.9  
{ s\dhQZw3  
System.err.println("Error Code : " + nErrorCode); $bo 5:c  
} /Q*c
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//停止文件下载 D`fi\A  
public void siteStop() T*irCe  
{ .BqSE  
bStop = true; &Dw8GU}1  
for(int i=0;i<nStartPos.length;i++) ~ @Au<  
fileSplitterFetch.splitterStop(); .pd_SQ~  
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`
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} u>I;Cir4  
} N,Ys}qP  
//负责部分文件的抓取 "H!2{l{  
**FileSplitterFetch.java =`y.L5  
*/ *3r{s'm  
package NetFox; G>H',iOI  
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import java.io.*; T.R(  
import java.net.*; hp6%zUR  
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2 bQC2  
public class FileSplitterFetch extends Thread { {S;/+X,  
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String sURL; //File URL DGllJ_/Z  
long nStartPos; //File Snippet Start Position w+Cs=!  
long nEndPos; //File Snippet End Position |e#ea~/b  
int nThreadID; //Thread's ID +ysP#uAA  
boolean bDownOver = false; //Downing is over \JX.)&> -  
boolean bStop = false; //Stop identical glvtumv  
FileAccessI fileAccessI = null; //File Access interface 2~BId&]  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Q?\rwnW?U  
{ 2n`OcXCh/  
this.sURL = sURL; T-L;iH~0  
this.nStartPos = nStart; "0yO~;a  
this.nEndPos = nEnd; kb>/R/,9  
nThreadID = id; beM}({:`  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ]\Tcy[5  
} U]h5Q.<SG  
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public void run() jSyF]$"  
{ L>qLl_.  
while(nStartPos < nEndPos && !bStop) 1vF^<{%v  
{ u4kg#+H  
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try{ $A/$M\:  
URL url = new URL(sURL); Wi?37EHr  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); b-x,`s  
httpConnection.setRequestProperty("User-Agent","NetFox"); +R_w- NI  
String sProperty = "bytes="+nStartPos+"-"; ZxR
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httpConnection.setRequestProperty("RANGE",sProperty); ,.ln  
Utility.log(sProperty); =Qcz:ng  
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InputStream input = httpConnection.getInputStream();
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//logResponseHead(httpConnection); 3Hli^9&OX_  
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byte[] b = new byte[1024]; `<C/-Au  
int nRead; B0^0d*8t|@  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) B0KZdBRx}  
{ 7xOrG],E  
nStartPos += fileAccessI.write(b,0,nRead); wER>a (  
//if(nThreadID == 1) JKkR963 O  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); P*#H]Pv  
} yBPaGZ{f  
`.FvuwP  
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Utility.log("Thread " + nThreadID + " is over!"); d2x|PpmH  
bDownOver = true; $Qv+*%c  
//nPos = fileAccessI.write (b,0,nRead); ~8-Z=-  
} H?P:;1A]c  
catch(Exception e){e.printStackTrace ();} C NNyz$  
} mGXjSWsd  
} Z5
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( *(#;|m  
//打印回应的头信息 eoS8e$}  
public void logResponseHead(HttpURLConnection con) \wxS~T<&L  
{ ]Xur/C2A  
for(int i=1;;i++) R18jju>Zr  
{ ov=[g l  
String header=con.getHeaderFieldKey(i); K>h=  
if(header!=null) 8gv\
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//responseHeaders.put(header,httpConnection.getHeaderField(header)); aIv>X@U}  
Utility.log(header+" : "+con.getHeaderField(header));
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else McgTTM;E  
break; XF{ g~M  
} Xz'pZ*Hr$v  
} z\,g %u41  
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public void splitterStop() n# %mL<  
{ u6AReL'f  
bStop = true; IRemF@  
} JRkC~fv  
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} Uj)~>V'  
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*v[WJ"8@  
/* y#:_K(A" k  
**FileAccess.java krPwFp2[*  
*//文件访问(定位，写) )QGj\2I  
package NetFox; c|lo%[]R!  
import java.io.*; 6uCa iPV  
&+\J "V8  
$!L'ZO1_r  
public class FileAccessI implements Serializable{ 3[E3]]OVa  
bu[v[U4  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 $ZD1_sJ.  
RandomAccessFile oSavedFile; {$,e@nn  
long nPos; :A\8#]3  
~a:0Q{>a  
8. [TPiUn'  
public FileAccessI() throws IOException 8,pnm  
{ hBf0kl  
this("",0); Fu0 dYN  
} NKD<VMcqw  
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public FileAccessI(String sName,long nPos) throws IOException QCFLi n+r  
{  `Nn=6[]  
oSavedFile = new RandomAccessFile(sName,"rw"); Z5re F
ok  
this.nPos = nPos; NDW6UF
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oSavedFile.seek(nPos); #Jv|zf5Z  
} 6f
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public synchronized int write(byte[] b,int nStart,int nLen) MzRwsf  
{ D.zEE-cGyb  
int n = -1; Vv4
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try{ k/A8|  
oSavedFile.write(b,nStart,nLen); 4k5X'&Q  
n = nLen; _jOu`1w  
} Ah,X?0+  
catch(IOException e) GsG.9nd  
{ )-q#hY  
e.printStackTrace (); ]a)o@FI  
}  ")MjR1p  
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return n; S>isWte  
} iB;EV8E  
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} #T1py@b0zA  
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F!*u}8/_!  
/* duCxYhh|  
**SiteInfoBean.java <R)%K);  
*/ p R=FH#  
package NetFox; z^z_!@7v   
\ s^a4l2  
q(sEN!^L`  
public class SiteInfoBean { =e2|:Ba!  
sdF;H[  
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private String sSiteURL; //Site's URL (3Hz=k_  
private String sFilePath; //Saved File's Path R57>z`;  
private String sFileName; //Saved File's Name @>n7  
private int nSplitter; //Count of Splited Downloading File kR2kV"-l  
DPCB=2E  
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public SiteInfoBean() n qSjP5  
{//nSplitter的缺省值为5 ME"B1Se\  
//default value of nSplitter is 5 n1+1/  
this("","","",5); #zflU99d  
} F!DDlYUz.  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Y5nj _xQJL  
{ ~NT2QY5!K  
sSiteURL= sURL; eT33&:n4  
sFilePath = sPath; )Qe<XJH!  
sFileName = sName; [=k$Q (.3  
this.nSplitter = nSpiltter; f]Jn\7j4  
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;}v#hKC~  
} ] TY$  
dm8
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86pujXjc'  
public String getSSiteURL() lrqu%:q  
{ xNlxi  
return sSiteURL; {nvF>  
} ctI
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public void setSSiteURL(String value) i\~@2  
{ NWnUXR  
sSiteURL = value; ^3re*u4b=  
} M)sM G C  
$*N^bj  
*AK{GfP_  
public String getSFilePath() ]fxYSm  
{ Z:>)5Z{'  
return sFilePath; t}FwS6u  
} =PU!hZj"L  
`sW+R=  
P/%5J3_,  
public void setSFilePath(String value) yN-o?[o  
{ X5[.X()M4  
sFilePath = value; v\&C]W]  
} %?<Y&t  
D,R"P }G  
>3aB{[[N  
public String getSFileName() \ @XvEx%  
{ B^|^hZZ>  
return sFileName; vndD#/lXq  
} CMu/n]?c  
ckDWY<@v  
t`F<lOKj  
public void setSFileName(String value) >|j8j:S[  
{ i|N%dl+T=  
sFileName = value; SZ$~zT;c  
} K=Q<G:+&V  
Bs?B\k=  
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public int getNSplitter() i&K-|[3{g  
{ %=w@c  
return nSplitter; o2'^MxKb T  
} Dx1f<A1  
IOL5p*:gz  
79HKfG2+KB  
public void setNSplitter(int nCount) ZMp5d4y5  
{ g>gVO@"b2  
nSplitter = nCount; Qqm$Jl!  
} 9:\#GOg  
} P5?M"j0/^  
qoZUX3{  
6h5DvSO  
/* 5vP=Wf cW  
**Utility.java d ,"L8  
*/ G~.bi<(v  
package NetFox; fx74h{3u  
c]Z@L~WW  
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public class Utility { KU;d[Z@g  
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public Utility() bM@8[&ta  
{ Ca]V%
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v% c-El%  
} vV$6fvS  
aG*Mj;J  
//线程睡眠 +uqP:z  
public static void sleep(int nSecond) F/ si =%  
{ pw, <0UhV  
try{ :Vnus @#r  
Thread.sleep(nSecond); T[(4z@d`5  
} a_V.mu6h6p  
catch(Exception e) S\jIs[Dz  
{ 9coN >y  
e.printStackTrace (); }57d3s  
} +$CO  
} #Y_v0.N  
E9N.b.Q)  
//日志 *B*dWMh  
public static void log(String sMsg) UL3++bt  
{ c{(4s6D  
System.err.println(sMsg); Bk yW
 
} ^`*p;&(K\^  
'Dx_n7&=  
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public static void log(int sMsg) Z*Lv!6WS  
{ h*lU&8)m\  
System.err.println(sMsg); uP.[,V0@^  
} HYcwtw6  
} i_'u:P<t  
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 \LP?,<  
/* 4*9WxhJ ]0  
**TestMethod.java 6 _n~E e  
*/ b!l/O2 G  
package NetFox; Jc9BZ`~i  
3:
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_/pdZM,V  
public class TestMethod { %Y
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u.!<)VIJx  
8]2j*e0xV  
public TestMethod() ^`f( Pg!  
{ ///xx/weblogic60b2_win.exe wK*b2r}0/  
try{ 0(h'ZV  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); -;s-*$I  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ^2<nn op  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 6>e YG<y{  
fileFetch.start(); uc?`,;8{`  
} {!av3Pz\  
catch(Exception e){e.printStackTrace ();} $ 0
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} :/6gGU>pu  
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public static void main(String[] args) =5D@~?W ZG  
{ |)pgUI2O[  
new TestMethod(); "v[?`<53^l  
} -MTO=#5z  
} r4wnfy  
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