http断点续传简单实现（java)

/* cH\.-5NQ  
**SiteFileFetch.java e?!A]2  
*/ Y[ toN9,  
package NetFox; i!EN/Bd  
import java.io.*; ?e!mv}B_  
import java.net.*; \*$''`b)j  
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public class SiteFileFetch extends Thread { c4n]#((%a  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 6N'v`p8  
long[] nStartPos; //开始位置 '\.fG\xD  
long[] nEndPos; //结束位置 (y!<^Q  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 1-60gI1)  
long nFileLength; //文件长度 (Y%pk76d  
boolean bFirst = true; //是否第一次取文件 MHkTN  
boolean bStop = false; //停止标志 OfGMeN6  
File tmpFile; //文件下载的临时信息 W-+~r  
DataOutputStream output; //输出到文件的输出流 Qyoly"b
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ^X/[x]UOT@  
public SiteFileFetch(SiteInfoBean bean) throws IOException ;y"quJ'O  
{ 8n^v,s>  
siteInfoBean = bean; N v,Yikf  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); h"{Z%XPX#  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info");  &(Ot
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if(tmpFile.exists ()) {\+!@?  
{ [vs5e3B)  
bFirst = false; ^ LTKX`p  
read_nPos(); 0]3#3TH  
} BHh%3Q  
else ?tLBEoUmKT  
{ yBwgLn  
nStartPos = new long[bean.getNSplitter()]; `w J^   
nEndPos = new long[bean.getNSplitter()];
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} H#luG_)  
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} A[@xTqs{{  
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public void run() E6  2{sA^  
{ .6m%/-whS  
//获得文件长度 I8C(z1(N  
//分割文件 ;LM,<QJ  
//实例FileSplitterFetch R
7)2@;i  
//启动FileSplitterFetch线程 h`0'27\C  
//等待子线程返回 hqA6%Y^k  
try{ `is."]%f  
if(bFirst) z+>FKAF  
{ +p:#$R)MW  
nFileLength = getFileSize(); I'M,p<B  
if(nFileLength == -1) ppjS|l*`  
{ 7n,*3;I  
System.err.println("File Length is not known!"); %B&y^mZv*\  
} ]D@_cxud3  
else if(nFileLength == -2) jW^@lH EU  
{ $y\\?  
System.err.println("File is not access!"); cg-\|H1  
} Z9MT, "  
else bcp+7b(IB  
{ 2cy: l03  
for(int i=0;i<nStartPos.length;i++) .]_ (>^6  
{ y my/`%  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 9%i|_c}  
} G(2(-x"+  
for(int i=0;i<nEndPos.length-1;i++) nwOT%@nw  
{ Z Sj[GI  
nEndPos = nStartPos[i+1]; |2#)lGA  
} gZI88Q  
nEndPos[nEndPos.length-1] = nFileLength; o& g01t  
} sOegR5?;  
} G1t{a:  
bG`aF*10)!  
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//启动子线程 &R? \q*  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; %s}c#n)N  
for(int i=0;i<nStartPos.length;i++) EZ6\pyNB0#  
{ 8<gYB$* S  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 0}a="`p#<  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), VM 3~W  
nStartPos,nEndPos,i); ){u/v[O9"  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); z+RA  
fileSplitterFetch.start(); `Ap<xT0H  
} gLyXe,Jp  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), >5rb4  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); z}>q/!q  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", '<}N`PS#N  
nEndPos = " + nFileLength); ws!pp\F  
// fileSplitterFetch[nPos.length-1].start(); 8F?6Aq1B  
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//等待子线程结束 T1\LS*~!  
//int count = 0; h!k[]bt5  
//是否结束while循环 rD"$,-h  
boolean breakWhile = false; k/6Qwb#  
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while(!bStop) us/}_r74N*  
{ nY]5pOF:  
write_nPos(); %25GplMT  
Utility.sleep(500); xL-]gwq  
breakWhile = true; ZDQc_{e{  
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for(int i=0;i<nStartPos.length;i++) Owe"x2D\  
{ ,;&j*qFi  
if(!fileSplitterFetch.bDownOver) M>eMDCB\  
{ i?{cB!7  
breakWhile = false; XLu Y  
break; XfYMv38(  
} 6cO36  
} Mj9Mv<io  
if(breakWhile)

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break; F gi&CJ8Q  
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//count++; <8 $fo  
//if(count>4) ZOAHM1ci  
// siteStop(); +D3w2C
 
} ^k*h  
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System.err.println("文件下载结束！"); vYPZVqF_$  
} -Lo3@:2i  
catch(Exception e){e.printStackTrace ();} Em<B9S  
} Whd\Ub8(  
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//获得文件长度 X[e:fW[e)  
public long getFileSize() k1.h|&JJN  
{ (C3:_cM5  
int nFileLength = -1; ~W>3EJghR,  
try{ V*Q!J{lj^#  
URL url = new URL(siteInfoBean.getSSiteURL()); s"'ns  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); !l(O$T9T  
httpConnection.setRequestProperty("User-Agent","NetFox"); J,W<vrKOcN  
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int responseCode=httpConnection.getResponseCode(); Pg''>6w>  
if(responseCode>=400) E',z<S  
{ u3G.xlHH[  
processErrorCode(responseCode); p.ks jD  
return -2; //-2 represent access is error D;Bij=  
} =$wQA  
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String sHeader; _?I6[Mz  
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for(int i=1;;i++) (g*mC7 HN  
{ v;WfcpWq2  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); r,r"?}Z  
//Utility.log(in.readLine()); 0^25uAD=  
sHeader=httpConnection.getHeaderFieldKey(i); 1C5~GI`  
if(sHeader!=null) %W8*vSbx  
{ uBUT84i  
if(sHeader.equals("Content-Length")) g9.y`o}c  
{ A=f)ntH~  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 8+n*S$  
break; [W8"Mc|ve  
}  oB8LJZ;  
} Q>yO,H|  
else }v`Z.?|Z  
break; sLOkLz"x  
} cl{kCSZo.z  
} GTocN1,Z~a  
catch(IOException e){e.printStackTrace ();} XEL~y  
catch(Exception e){e.printStackTrace ();} (RBB0CE  
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Utility.log(nFileLength); L$3{L"/   
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return nFileLength; iI$;%uY3g  
} y;VmA#k`  
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//保存下载信息（文件指针位置） mum4Uj  
private void write_nPos() [l*;+N+  
{ X?z CB  
try{ vVFT0_  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ?2<V./2F  
output.writeInt(nStartPos.length); Ol)
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for(int i=0;i<nStartPos.length;i++) M6lNdK  
{ G7YBo4v  
// output.writeLong(nPos); 'p&q}IO  
output.writeLong(fileSplitterFetch.nStartPos); *EF`s~  
output.writeLong(fileSplitterFetch.nEndPos); CPLsSv5  
} jJK@i\bU_  
output.close(); |o#pd\  
} mc|8t0+1`  
catch(IOException e){e.printStackTrace ();} ]owcx=5q%'  
catch(Exception e){e.printStackTrace ();} '"9Wt@ .  
} )P#xny2  

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//读取保存的下载信息（文件指针位置） UJ^-T+fut  
private void read_nPos() **~1`_7~*  
{ 4Ep6vm X  
try{ W744hq@P%  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); FJIo]p  
int nCount = input.readInt(); `e}6/~R`  
nStartPos = new long[nCount]; DxzNg_E]  
nEndPos = new long[nCount]; }3S6TJ+  
for(int i=0;i<nStartPos.length;i++) iz:O]kI  
{ znNv;-q  
nStartPos = input.readLong(); hEfFMi=a`  
nEndPos = input.readLong(); 9@8)ZHf  
} T%@qlEmf  
input.close(); wQrD(Dv(yA  
} ~?:Xi_3Lo
 
catch(IOException e){e.printStackTrace ();} DX<xkS[P  
catch(Exception e){e.printStackTrace ();} 1V;
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} JA "  
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private void processErrorCode(int nErrorCode) 0T<DHPQ1  
{ `E5vO1Pl  
System.err.println("Error Code : " + nErrorCode); )B5(V5-!|  
} c\N-B,m&  
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//停止文件下载 xwZ7I  
public void siteStop() ziG]BZ  
{ 

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bStop = true; LO;Z3Q>#0  
for(int i=0;i<nStartPos.length;i++) V1\x.0Fs  
fileSplitterFetch.splitterStop(); hG>3y\!#  
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} U66zm9 3&  
} FW!1 0K?  
//负责部分文件的抓取 =f-.aq(G/  
**FileSplitterFetch.java  u9,ZY>  
*/ ] KR\<MJK  
package NetFox; \&1Di\eL  
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import java.io.*; I DtGtkF  
import java.net.*; ~riV9_-  
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public class FileSplitterFetch extends Thread { o_DZ  
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String sURL; //File URL pxO?:B  
long nStartPos; //File Snippet Start Position 8A3!XA  
long nEndPos; //File Snippet End Position |h75S.UY  
int nThreadID; //Thread's ID WMXk-?v4  
boolean bDownOver = false; //Downing is over Ex3V[v+D(  
boolean bStop = false; //Stop identical >XiTl;UU  
FileAccessI fileAccessI = null; //File Access interface Y]!{ nW  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ILq"/S.  
{ vTF_`X  
this.sURL = sURL; PgF7ug%,@C  
this.nStartPos = nStart; ,c\3b)ax  
this.nEndPos = nEnd; "lJ[H=\  
nThreadID = id; .}zpvr8YP  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 _& qM^  
} .ko}m{  
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public void run() /\&Wk;u3  
{ .|g67PH=  
while(nStartPos < nEndPos && !bStop) X#!oG)or  
{ #aV2+`d  
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try{ umD[4aP~;  
URL url = new URL(sURL); zxt&oT0Q  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); :Sj r  
httpConnection.setRequestProperty("User-Agent","NetFox"); "Lp"o  
String sProperty = "bytes="+nStartPos+"-";
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httpConnection.setRequestProperty("RANGE",sProperty); $2j?Z.yEG  
Utility.log(sProperty); .g6DKjy>  
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InputStream input = httpConnection.getInputStream(); 4vk^=  
//logResponseHead(httpConnection); }m6j6uAR6)  
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byte[] b = new byte[1024];  FGP~^Dr/  
int nRead; m%hUvG| i  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) gZs UX^%  
{ H' [#x2  
nStartPos += fileAccessI.write(b,0,nRead); A%G \ AT  
//if(nThreadID == 1) gTp){  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); - :0{  
} 'e(`
2  
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Utility.log("Thread " + nThreadID + " is over!"); : Jh  
bDownOver = true; Z-!W#   
//nPos = fileAccessI.write (b,0,nRead); /Nh:O  
} +=y ktf  
catch(Exception e){e.printStackTrace ();} VvO/  
} U 6y ;V  
} I\0m
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#<7ajmr  
//打印回应的头信息 psg}sl/  
public void logResponseHead(HttpURLConnection con) o'3t(dyyH  
{ xpf\S10e  
for(int i=1;;i++) jF'azlT  
{ ZcXqH7`r  
String header=con.getHeaderFieldKey(i); hwmpiyu  
if(header!=null) ?^F#}>C  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 'y#kRC=G:  
Utility.log(header+" : "+con.getHeaderField(header)); VxOrrs7Z  
else }31z 35  
break; Sdc;jK 9d!  
} {.We%{
4V  
} h-1eDxK6  
VY'#>k}}  
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public void splitterStop() P]Z}% 8^O  
{ t/,k{5lX  
bStop = true; T|p$Ddt`+  
} |5}{4k~9J  
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} ku*|?uF  

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/* BCya5!uy  
**FileAccess.java snTj!rV/_  
*//文件访问(定位，写) bQk5R._got  
package NetFox; XcA4EBRj  
import java.io.*; EIl _QV6  
1$f
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mp~\ioI*d  
public class FileAccessI implements Serializable{ >Lanuv)O  
-aGv#!aIl  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 f#414ja  
RandomAccessFile oSavedFile; |B4dFI?  
long nPos; `3r*Ae  
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public FileAccessI() throws IOException 7,|-%!p[  
{ Hux#v>e  
this("",0); SZc6=^$  
} (~{7e/)r  
:$[m[y7i  
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public FileAccessI(String sName,long nPos) throws IOException Zx5vIm  
{ 0;e>kz3o  
oSavedFile = new RandomAccessFile(sName,"rw"); vVKiE 6^  
this.nPos = nPos; z]\0]i  
oSavedFile.seek(nPos); =Ze~6vS,  
} Jx_ OT C  
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public synchronized int write(byte[] b,int nStart,int nLen) ,[+gE\z{{u  
{ Qd]-i3^0  
int n = -1; RsVba!x@  
try{ 2hf]XV\  
oSavedFile.write(b,nStart,nLen); 34]f[jJ|  
n = nLen; p%J,af  
} /5
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catch(IOException e) Pp3t
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{ KWy4}7a@,s  
e.printStackTrace (); ngEjbCV+  
} ~|Gtm[9Ru  
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._  
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return n; (sO;etW  
} Z'WoChjM  
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} $}W=O:L+D  
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/* im%'S6_X4  
**SiteInfoBean.java 3boINmX  
*/ Jh M.P9  
package NetFox; 0l^-[jK)  
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public class SiteInfoBean { cRT@Cu  
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private String sSiteURL; //Site's URL Bz9!a
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private String sFilePath; //Saved File's Path GvF~h0wMt  
private String sFileName; //Saved File's Name 8WZM}3x$f{  
private int nSplitter; //Count of Splited Downloading File bb+-R_3Kd  
[=7|LHjU  
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public SiteInfoBean() #r#UO  
{//nSplitter的缺省值为5 4[Hf[.  
//default value of nSplitter is 5 cZZ-K?_  
this("","","",5); b)3dZ*cOJ  
} ,>`wz^z  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) mcpM<vY/H  
{ B;2os^*  
sSiteURL= sURL; ^6Hfq^ejt  
sFilePath = sPath; ujmO'blO  
sFileName = sName; +i4S^B/8i  
this.nSplitter = nSpiltter; a~9U{)@F  
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# 0dN!l;  
} go@UE2qw  
,L6d~>=41  
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public String getSSiteURL() ZXFM_>y5  
{ z
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return sSiteURL; ,<d[5;7x  
} C~yfuPr\B  
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public void setSSiteURL(String value) _b&Mrd  
{ +=)< Su.  
sSiteURL = value; o6'I%Gs  
} mawomna  
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public String getSFilePath() 4h@jJm  
{ ~>VEg3#F  
return sFilePath; SsIy;l  
} C5CUMYU  
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public void setSFilePath(String value) j\B]>PP5  
{ d(3F:dbk  
sFilePath = value; =;W"Pi;*  
} j&6,%s-M`a  
@{iws@.  
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public String getSFileName() $3[IlQ?  
{ "o2p|2c  
return sFileName; 5|my}
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} w},' 1  
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public void setSFileName(String value) Nwr.mtvh  
{ 5+vCuVZ  
sFileName = value; }fpK{db  
} an_qE}P  
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*;"N kCf  
public int getNSplitter() 8c(}*,O/  
{ 7!+kyA\}r^  
return nSplitter; (~:k70V5  
} +c.A|!-  
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public void setNSplitter(int nCount) 1sl^+)z8  
{ ?VrZ
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nSplitter = nCount; 8 !Pk1P  
} T)&J}^j  
} $e&( ncM  
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/* nF~</>  
**Utility.java 7Bm 18  
*/ kq6S`~J^R  
package NetFox; X|K"p(N  
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public class Utility { R$'4 d  
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public Utility() ["- pylhK  
{
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} @P#uH5U  
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//线程睡眠 g <^Y^~+E  
public static void sleep(int nSecond) +5H9mk  
{ \?c0XD  
try{ "'h?O*V]u{  
Thread.sleep(nSecond); La48M'u  
} ztf VXmi'  
catch(Exception e) :_JZn`Cab  
{ jLX{$,  
e.printStackTrace (); j8
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} s|
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} x7K   
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//日志 O&l
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public static void log(String sMsg) bhe~ekb  
{ v39`ct=e  
System.err.println(sMsg); hDJq:g wD  
} TU$PAwn=  
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public static void log(int sMsg) ,Q4U<`ds!  
{ g\)+ LX  
System.err.println(sMsg); X).UvPZ/  
} *F*c  
} r \H+=2E'  
7Ipt~K}  
R~8gw^w![  
/* \kcJF'JFA0  
**TestMethod.java v1<gNb)`  
*/ ;Q&38qI  
package NetFox; E@TX>M-&  
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@3KVYv,q  
public class TestMethod { 'E
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7IW:,=Zk8+  
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public TestMethod() IK5FSN]s/  
{ ///xx/weblogic60b2_win.exe W"S,~y  
try{ DfwxPt#
 
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); :0IxnK(r&  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 6cz%>@  
SiteFileFetch fileFetch = new SiteFileFetch(bean); (q`Jef  
fileFetch.start(); u\=gps/Z  
} J XKps#,(#  
catch(Exception e){e.printStackTrace ();} !Sr^4R+Z  
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} xb\(>7M6Y  
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public static void main(String[] args) ^4(CO[|c~  
{ GjZ@fnF  
new TestMethod(); S_LY>k?  
} q88p~Ccoa  
} S+>&O3m  
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