http断点续传简单实现（java)

/* :(S/$^U  
**SiteFileFetch.java [6/%V>EM  
*/ T`RQUJO  
package NetFox; "oj
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import java.io.*; )l[7;ZIw$  
import java.net.*; l;][Q]Z@V  
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v @I^:I  
public class SiteFileFetch extends Thread { <'4!G"_EP  
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SiteInfoBean siteInfoBean = null; //文件信息Bean #LNB@E  
long[] nStartPos; //开始位置 L2/<+Zw  
long[] nEndPos; //结束位置 <7
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FileSplitterFetch[] fileSplitterFetch; //子线程对象 pRk'GR]`  
long nFileLength; //文件长度 _uy5?auQ  
boolean bFirst = true; //是否第一次取文件 |V~(mS747:  
boolean bStop = false; //停止标志 7,&]1+n  
File tmpFile; //文件下载的临时信息 .>gU 9A(Nk  
DataOutputStream output; //输出到文件的输出流 hF=V
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） h.s<0.  
public SiteFileFetch(SiteInfoBean bean) throws IOException g8iB;%6   
{ /kviO@jm4(  
siteInfoBean = bean; $Zu4tuXA  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 7PQj7&m  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); g)r,q&*  
if(tmpFile.exists ()) )/N Xh'  
{ xdTzG4  
bFirst = false; U0|j^.)  
read_nPos(); m?R+Z6c[  
} U}vtVvx  
else (EF$^FYPK  
{ I;":O"ij\  
nStartPos = new long[bean.getNSplitter()]; |)P;%Fy9  
nEndPos = new long[bean.getNSplitter()]; ^x1D]+  
} x+)hL D[ n  
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} Lw2YP[CR  
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public void run() Rp@}9qijb  
{ k f K"
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//获得文件长度 ZsK'</7  
//分割文件 +[l{C+p  
//实例FileSplitterFetch I}Gl*@K&O  
//启动FileSplitterFetch线程 )*L?PT  
//等待子线程返回 ;Wrd=)Ka  
try{  d7-F&!sQ  
if(bFirst) $lG--s  
{ 7[?}kG   
nFileLength = getFileSize(); >8mW-p  
if(nFileLength == -1) #<V
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{ 5bqYi  
System.err.println("File Length is not known!"); :-'ri Ry  
} LM`tNZ1Fc!  
else if(nFileLength == -2) cF<DUr)Ve  
{ pcxl2I  
System.err.println("File is not access!"); ()IgSj?,  
} #
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else qP.VK?jF|  
{ );.<Yf{c  
for(int i=0;i<nStartPos.length;i++) qaSv]k.  
{ 1p5q}">z  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 93p9?4;n-  
} RkXLE"G'  
for(int i=0;i<nEndPos.length-1;i++) !
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{ FUv)<rK  
nEndPos = nStartPos[i+1]; $YO]IK$  
} 6I.+c
 
nEndPos[nEndPos.length-1] = nFileLength; '~6CGqU*  
} 0PX@E-n  
} 1ZH8/1gWI  
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//启动子线程 Z.Y8z#[xg  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Zo6a_`)d  
for(int i=0;i<nStartPos.length;i++) ^J=txsx  
{ sAAIyPJts  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ewlc ^`  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), &7y1KwfXn  
nStartPos,nEndPos,i); oTa+E'q  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); I3=Sc^zz&V  
fileSplitterFetch.start(); Wv'B[;[)  
} Vblf6qaBs  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 5suSR;8  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); hdDI%3vk3  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", a+Qj[pS  
nEndPos = " + nFileLength); pDS4_u  
// fileSplitterFetch[nPos.length-1].start(); fHp#Gi3Lz  
\Hx#p`B%  
 k`zK  
//等待子线程结束 (HgdmN%  
//int count = 0; f2K3*}P  
//是否结束while循环 $fpDABf  
boolean breakWhile = false; '`VO@a  
;iI2K/ 3  
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while(!bStop) SxQDqoA~  
{ ;@\JscNJ|  
write_nPos(); x~,?Zj)n?C  
Utility.sleep(500); ll^O+>1dO  
breakWhile = true; e/I{N0SR  
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for(int i=0;i<nStartPos.length;i++) IaqN@IlWb  
{ 6E%k{ r  
if(!fileSplitterFetch.bDownOver) .:Xe*Q  
{ ?fwr:aP~  
breakWhile = false; t-{OP?c
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break; jS)-COk  
} )n61IqrW  
} c^UM(bW  
if(breakWhile) Tfs9<k>G#  
break; j[ YTg]  
9_^V1+   
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//count++; %ieAY-<"  
//if(count>4) w0OK.fj  
// siteStop(); ({62GWnn_  
} T>?1+mruM  
: .e
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System.err.println("文件下载结束！"); z@LP9+?dE  
} E 4(muhY  
catch(Exception e){e.printStackTrace ();} 5WX2rJ8z  
} nsn,8a38  
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//获得文件长度 P=i |{vv(  
public long getFileSize() JIk
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{ :zZM&r>  
int nFileLength = -1; z>q_]U0  
try{ gC:E38u  
URL url = new URL(siteInfoBean.getSSiteURL()); "A$Y)j<#G  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ^E8Hv  
httpConnection.setRequestProperty("User-Agent","NetFox"); L^Af3]]2  
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int responseCode=httpConnection.getResponseCode(); z(a:fL{/XG  
if(responseCode>=400) g7ROA8xu  
{ $a]dxRkz  
processErrorCode(responseCode); D{}\7qe  
return -2; //-2 represent access is error eS+LFS7*k  
} =swcmab;  
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String sHeader; N($]))~3&  
=sJHnWL[  
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for(int i=1;;i++) =1uI >[aN  
{ Np)!23 "  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); {RO=4ba{J  
//Utility.log(in.readLine()); -4a&R=%p  
sHeader=httpConnection.getHeaderFieldKey(i); YRXe j  
if(sHeader!=null) l#:Q V:  
{ r#}%sof  
if(sHeader.equals("Content-Length")) mcracj[B  
{ Q?q m~wD  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); m]vr|:{6/  
break; Sy~Mh]{E  
} %?y`_~G  
} {hR23eE)#  
else \/GY0s  
break; Gj?q+-d!(5  
} ]].21  
} O2B$c\pw  
catch(IOException e){e.printStackTrace ();} r3)t5P*_  
catch(Exception e){e.printStackTrace ();} %dQX d]  
w,$17+]3  
@ vudeaup  
Utility.log(nFileLength); [HfFC3U  
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return nFileLength; <WmCH+>?r  
} )<&QcO_  
;U4X U  
Hs` '](  
//保存下载信息（文件指针位置） HBu>BSv:  
private void write_nPos() YG|T;/-  
{ }Z=Qy;zk  
try{ pq`MO .R  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 1x)%9u}  
output.writeInt(nStartPos.length); aV.<<OS   
for(int i=0;i<nStartPos.length;i++) .j.=|5nVo4  
{ c eX*|B@=  
// output.writeLong(nPos); BcWReyO<M  
output.writeLong(fileSplitterFetch.nStartPos); >oNs_{  
output.writeLong(fileSplitterFetch.nEndPos); w5Z3e^g  
} gsH_pG-jU  
output.close(); CaMG$X&O  
} VP&lWPA}\$  
catch(IOException e){e.printStackTrace ();} ShP V!$0  
catch(Exception e){e.printStackTrace ();} `.XU|J*z,  
} Ab)7hCUW  
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//读取保存的下载信息（文件指针位置） M`FL&Ac  
private void read_nPos() GKr L  
{ 8Sa<I.l  
try{
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DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ,`b9c=6;  
int nCount = input.readInt(); I`l<}M  
nStartPos = new long[nCount]; #e[5O|V~  
nEndPos = new long[nCount]; +{Ttv7l_2  
for(int i=0;i<nStartPos.length;i++) a6C~!{'nW  
{ K9iR>put  
nStartPos = input.readLong(); G.8ZISN/  
nEndPos = input.readLong(); N 2\,6<  
} |BR&p)7)  
input.close(); M'sJ5;^5  
} d!cx%[  
catch(IOException e){e.printStackTrace ();} &H6Fkza;4  
catch(Exception e){e.printStackTrace ();} QQJcvaQ  
} FrS>.!OFn  
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private void processErrorCode(int nErrorCode) b~-9u5.L1  
{ =:DNb(  
System.err.println("Error Code : " + nErrorCode); IN"qJ3<k  
} ?p]w_l  
+9t@eHJT1  
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//停止文件下载 ]v#Q\Q8>  
public void siteStop() uzOZxW[e  
{ ul E\>5O4h  
bStop = true;  *hba>LZ  
for(int i=0;i<nStartPos.length;i++) sE% n=Ww  
fileSplitterFetch.splitterStop(); _kfApO)O  
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} c8'?Dd  
} ;XjKWM;  
//负责部分文件的抓取 TSeAC[%pL  
**FileSplitterFetch.java 3't?%$'5  
*/ wp$=lU{B  
package NetFox; TX;|g1K  
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import java.io.*; Xv9CD  
import java.net.*; };
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public class FileSplitterFetch extends Thread { 7ORwDR,`5  
<5 okwcJ^  
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String sURL; //File URL 0W@C!mD~  
long nStartPos; //File Snippet Start Position `KZ}smMA  
long nEndPos; //File Snippet End Position r~X6qC  
int nThreadID; //Thread's ID NGNn_1  
boolean bDownOver = false; //Downing is over I>:'
5V  
boolean bStop = false; //Stop identical Xo P]PR`cQ  
FileAccessI fileAccessI = null; //File Access interface lw7wvZD  
0 }q/VH57  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException f_}55?i0  
{ K/altyj`  
this.sURL = sURL; 0@2%pIq\  
this.nStartPos = nStart; s`TfNwDvU  
this.nEndPos = nEnd; _:T\[sz5  
nThreadID = id; 18~j>fN  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 C)`/Q(^  
} rz4S"4  
:E.mU{  
*fl1 =Rfr  
public void run() !JJY(o  
{ "p<f#s}  
while(nStartPos < nEndPos && !bStop) wI)W:mUZZ  
{ ]RV6(|U4_  
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try{ _uDtRoI8  
URL url = new URL(sURL); @qeI4io-n  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); kj>XKZL10  
httpConnection.setRequestProperty("User-Agent","NetFox"); ?P}7AF A(W  
String sProperty = "bytes="+nStartPos+"-"; Q16RDQ*  
httpConnection.setRequestProperty("RANGE",sProperty); s:M:Ff  
Utility.log(sProperty); VXC_Y  
*<J**FhcMu  
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InputStream input = httpConnection.getInputStream(); j5AW}  
//logResponseHead(httpConnection); 9+pnpaZB0  
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byte[] b = new byte[1024]; 07n=H~yU  
int nRead; W Qe>1   
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ]ko>vQ4]3  
{ `CW=*uBH  
nStartPos += fileAccessI.write(b,0,nRead); M^H357r%  
//if(nThreadID == 1) Xod#$'M>  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); _bW#* Y5  
} m%akx@{WL  
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Utility.log("Thread " + nThreadID + " is over!"); (g5T2(_6L  
bDownOver = true; 6ZX{K1_q  
//nPos = fileAccessI.write (b,0,nRead); d^4!=^HN  
} 8g$pfHt|e  
catch(Exception e){e.printStackTrace ();} :0r@o:H  
} gmt`_Dpm$  
} B\BP:;"  
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"H6DiPh.E  
//打印回应的头信息 .F |yxj;I7  
public void logResponseHead(HttpURLConnection con) L ej3? k  
{ sOv:/'
 
for(int i=1;;i++) %<P&"[F]v@  
{ b16\2%Ea1  
String header=con.getHeaderFieldKey(i); zK?[6n89f  
if(header!=null) $5(co)C  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); .a?GC(  
Utility.log(header+" : "+con.getHeaderField(header)); %vgn>A?]1  
else pf[bOjtR  
break; aR+vY1d"  
} uPt({H  
} 8KN0z<  
/ F9BbG{  
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public void splitterStop() ] vQn*T"^  
{ kk& ([xqU  
bStop = true; ("ql//SL  
} SK#;/fav6  
*$
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} x+47CDDu3  
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/* FZO}+ P  
**FileAccess.java p{NVJ^!+  
*//文件访问(定位，写) VM88#^  
package NetFox; ~}+F$&  
import java.io.*; gM&XVhQJ\  
*i?#hTw  
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public class FileAccessI implements Serializable{ "K;f[&xO,o  
|L,_QXA2  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Onz@A"  
RandomAccessFile oSavedFile; c7Jfo x V  
long nPos; V9bn  
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public FileAccessI() throws IOException )lwxFP;  
{ \AQ*T`Dq  
this("",0); ~nDbWv"  
} ?)X0l  
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public FileAccessI(String sName,long nPos) throws IOException K!g!tA$  
{ %=e^MN1  
oSavedFile = new RandomAccessFile(sName,"rw"); fAYp\k  
this.nPos = nPos; .Yg7V'R1  
oSavedFile.seek(nPos); (.^KuXd  
} 4sMA'fG  
>sGIpER7  
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public synchronized int write(byte[] b,int nStart,int nLen) OXDEU.  
{ =e*S h0dK  
int n = -1; <aSjK#  
try{ l^!raoH]q  
oSavedFile.write(b,nStart,nLen); jJbS{1z  
n = nLen; [+;>
u|  
} \8Y62  
catch(IOException e) cb82k[L6  
{ xaI)d/  
e.printStackTrace (); vX30Ijm  
} *{<460`!q  
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return n; xlIVLv6dO  
} *jCHv  
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} T0|hp7WM  
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/* #kQ1,P6,(  
**SiteInfoBean.java C[R|@9NI  
*/ yU|=)p5  
package NetFox; Lrjp  
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public class SiteInfoBean { 0JE*|CtK  
6DVHJ+WTV  
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private String sSiteURL; //Site's URL ?Gx-q+H  
private String sFilePath; //Saved File's Path %6Y\4Fe  
private String sFileName; //Saved File's Name VXPsYR&  
private int nSplitter; //Count of Splited Downloading File ^6@6BYf)  
n#PXMD*  
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public SiteInfoBean() Z6fR2A~Q[  
{//nSplitter的缺省值为5 B-p ].  
//default value of nSplitter is 5 "G!,gtA~  
this("","","",5); o0kKf+[  
} nmw#4yHYy:  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 8;i
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{ \SooIEl@  
sSiteURL= sURL; goZw![4l  
sFilePath = sPath; 5Z>+NKQ  
sFileName = sName; w""  
this.nSplitter = nSpiltter; Rhzcm`"  
\iH\N/  
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} v*&WqVg  
}F-,PSH Ml  
.*Axr\x3  
public String getSSiteURL() vMYEP_lhK,  
{ Nazr4QU  
return sSiteURL; vv1W<X0e<  
} Bgs,6:  
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7 V=%&+  
public void setSSiteURL(String value) m }\L i]  
{ FTh/1"a  
sSiteURL = value; Q[.d  
} V4. }wz_Y  
:@,UPc-+  
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public String getSFilePath() $yZ(ws  
{ lj %k/u  
return sFilePath; L8cPNgZ   
} 6AKT-r.  
}/VSIS@Z  
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public void setSFilePath(String value) tVHQ$jJY%  
{ 1-}$sO c  
sFilePath = value; W C3b_ia  
} ^"4u1  
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public String getSFileName() oT^r  
{ l`vr({A  
return sFileName; $F~hL?"?  
} V5]:^=  
)}SiM{g  
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public void setSFileName(String value) )q'~<QxI\  
{ J.pe&1  
sFileName = value; OuU]A[r  
} E']Gh  
bn8?-  
}$1Aw%p^  
public int getNSplitter() P8;f^3V(+/  
{ fa;GM7<e)  
return nSplitter; O:(%m  
} :@q9ll`6u  
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public void setNSplitter(int nCount) JulxFjC  
{ (r )fx  
nSplitter = nCount; cRC)99H
P  
} IXmO1*o@  
} !Y
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/* }V %b  
**Utility.java ]qk/V:H:  
*/ cP MUu9du  
package NetFox; "227 U)Q  
7<VfE`Q3  
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public class Utility { )04lf*ti  
^NTOZ0x~#
 
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public Utility() c~UYs\  
{ id.W"5+  
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} R4|<Vp<U2  
4r [Tpb  
//线程睡眠 o s HE4x  
public static void sleep(int nSecond) WwDxZ>9jw  
{ -j_J1P0,  
try{ &p$SFH?s  
Thread.sleep(nSecond); B1A5b=6G<  
} UI:{*N**Z  
catch(Exception e) a4}2^K  
{ b_ |  
e.printStackTrace (); ]4>[y?k34  
} z,oqYU\:  
} Yn}_"FO'  
xW,(d5RtZ  
//日志 f.=4p^  
public static void log(String sMsg) Zh.fv-Ecp  
{ tH"SOGfSt  
System.err.println(sMsg); %zyMWC  
} 3HA$k[%7P  
5b[:B~J  
^F~e?^s  
public static void log(int sMsg) #?i#q%q  
{ 5@Q4[+5&_  
System.err.println(sMsg); K0\a+6kh  
} z[S,hD\w  
} 
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As (C8C<  
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/* 7Yxy2[  
**TestMethod.java <E BgHD)  
*/ vd /_`l.D  
package NetFox; KF'H|)!K  
ooIMN =  
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public class TestMethod { Ytx+7OLe  
=,[46 ;q  
H8K<.RY  
public TestMethod() Xx|&%b{{r  
{ ///xx/weblogic60b2_win.exe 4'54  
try{ 5.[{PJ]bq  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5);  cJ8F#t  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); fsjA7)/  
SiteFileFetch fileFetch = new SiteFileFetch(bean); *-|+phim  
fileFetch.start(); 7^iF,
N  
} NTL#!  
catch(Exception e){e.printStackTrace ();} @LL&ggV?  
}h_Op7.5D  
a LmVOL{  
} D?\K~U* >  
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public static void main(String[] args) Xp} vJl   
{ 2hJ{+E.m  
new TestMethod(); U*&ZQw  
} dWqFP  
} M@'V4oUz  
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