http断点续传简单实现（java)

/* V6ECL6n  
**SiteFileFetch.java &<#1G u_  
*/ ~7j-OWz9  
package NetFox; jX'pUO  
import java.io.*; @|<nDd{2  
import java.net.*; %vf;qVoA~  
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WSeiW  
public class SiteFileFetch extends Thread { M7Z&t'=  
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SiteInfoBean siteInfoBean = null; //文件信息Bean .AX%6+o  
long[] nStartPos; //开始位置 cuG;1,?b  
long[] nEndPos; //结束位置 S+6YD0  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 y#Nrq9r:  
long nFileLength; //文件长度 S]T71W<i  
boolean bFirst = true; //是否第一次取文件 p}GTOJT}  
boolean bStop = false; //停止标志 ;>>:7rdYt  
File tmpFile; //文件下载的临时信息 H.n|zGQTB  
DataOutputStream output; //输出到文件的输出流 b;;y|H  
6,CK1j+tZ  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） S=< ]u  
public SiteFileFetch(SiteInfoBean bean) throws IOException LfrjC@_y  
{ ;
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siteInfoBean = bean; 8zeD%Uv  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 4;Hm%20g  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); h\)ual_r[j  
if(tmpFile.exists ()) 4K;0.W;~|  
{ 26_PFHQu4  
bFirst = false; ;$!0pxL)s  
read_nPos(); MD1d  
} c}=[r1M*  
else &,XPMT  
{ zYPvpZV/  
nStartPos = new long[bean.getNSplitter()]; _6nza)OFH  
nEndPos = new long[bean.getNSplitter()]; WpI5C,3Z!l  
} WV|9d}5  
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} \n#l+
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public void run() m`XaY J  
{ r 3T#Nv  
//获得文件长度 M tDJ1I%  
//分割文件 J{EK}'  
//实例FileSplitterFetch rA_r$X  
//启动FileSplitterFetch线程 _cfAJ)8=  
//等待子线程返回 |~D~#Nz  
try{ ~te{9/   
if(bFirst) /oM&29 jy  
{ ~fgS"F^7n  
nFileLength = getFileSize(); ,tBc%&.f  
if(nFileLength == -1) %HZ!s `w_  
{ \=W t{  
System.err.println("File Length is not known!"); {2|sk9?W  
} lQ.3_{"s  
else if(nFileLength == -2) /KJWo0zo  
{ Tc;BE  
System.err.println("File is not access!"); 9fSX=PVRmQ  
} uTrGb:^  
else Tkf4`Gxd  
{ %%O_:@9x,  
for(int i=0;i<nStartPos.length;i++) Zq}Cl'f  
{ 7,9zj1<  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); X.)1>zk  
} #>$w9}gFi  
for(int i=0;i<nEndPos.length-1;i++) | qf8y  
{ vs.}Bou]  
nEndPos = nStartPos[i+1]; LrV4^{9(  
} V SH64  
nEndPos[nEndPos.length-1] = nFileLength; w$I$xup  
} Zf\It<zT5  
} oP<E)  
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o648 xUP  
//启动子线程 <_Po/a!c3  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; W.b?~  
for(int i=0;i<nStartPos.length;i++) U./1OZ&  
{ BA0.B0+"  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), dG]s_lb9H  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), kmL~H1qd  
nStartPos,nEndPos,i); +Mh9Jf  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); A832z`  
fileSplitterFetch.start(); pK2n'4 C  
} _UeIzdV9  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(),
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); k{$Mlt?&-  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", w~9=6|_  
nEndPos = " + nFileLength); {I_I$x_  
// fileSplitterFetch[nPos.length-1].start(); <~qhy{hRn  
9_S>G$
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|a Ht6F  
//等待子线程结束 8|#p
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//int count = 0; !;C *Wsp}  
//是否结束while循环 2KmPZ&r  
boolean breakWhile = false; 9ev"BO  
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while(!bStop) F_Mi/pB^`9  
{ G@n%P~  
write_nPos(); 5/{gY{  
Utility.sleep(500); =l9H]`T/  
breakWhile = true; =}AwA5G  
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for(int i=0;i<nStartPos.length;i++) SA$1rqU=  
{ 4q5bW+$Xj  
if(!fileSplitterFetch.bDownOver) ?l<u%o  
{ FmRa]31W  
breakWhile = false; e6?h4}[+*  
break; ;yH1vX  
} vN4g#,<  
} s*j0uAq)up  
if(breakWhile) M%2F7 FY  
break; XmoS$/#"  
%sLij*  
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//count++; o93A:fc  
//if(count>4) _7zER6#}  
// siteStop(); 4 p(KdYc  
} 
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M
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System.err.println("文件下载结束！"); :3Z"Qk$uR  
} /\9X0a2h|E  
catch(Exception e){e.printStackTrace ();} l;g8_uyjv7  
} aTy&"  
f&ym'S  
!>+Na~eN  
//获得文件长度 J5Tl62}  
public long getFileSize() =r:-CRq(  
{ cy6P=k*  
int nFileLength = -1; x~tG[Y2F?  
try{ 7MT[fA8^  
URL url = new URL(siteInfoBean.getSSiteURL()); k iCg+@nT  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); )rs);Pl  
httpConnection.setRequestProperty("User-Agent","NetFox"); ~T[m{8uh  
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/\KB*dX  
int responseCode=httpConnection.getResponseCode(); MW+]w~7_Q  
if(responseCode>=400) %h%^i   
{ s^$zOp9  
processErrorCode(responseCode); lLT;V2=osX  
return -2; //-2 represent access is error xCV3HnZ  
} =ITMAC\  
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String sHeader; h&vq}  
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#9Z*.  
for(int i=1;;i++) 5xHl6T+  
{ pr[[)[]/  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); T(^<sjOs  
//Utility.log(in.readLine()); %o+VZEH3  
sHeader=httpConnection.getHeaderFieldKey(i); $CVbc%  
if(sHeader!=null) )*iSN*T8q  
{ P$\vD^  
if(sHeader.equals("Content-Length")) GIDC'  
{ <Ep-aRI  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); }IGr%C(3%  
break; x=bAR%i~  
} dOe|uQXyD  
} >w?O?&Q$  
else J~:/,'Ea  
break; w7"Z@$fs  
} KwRO?G9&  
} )A['+s  
catch(IOException e){e.printStackTrace ();} .Tdl'y:..  
catch(Exception e){e.printStackTrace ();} y@G5I>v  
,bCPO`45  
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Utility.log(nFileLength); U&/Jh^Yy  
W&6P%0G/  
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return nFileLength; 2Fce| Tn  
} It4J\S
 
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//保存下载信息（文件指针位置） Q<r O5 -K  
private void write_nPos() b#.hw2?a`  
{ -iS\3P.  
try{ 8+uwzBNZ:  
output = new DataOutputStream(new FileOutputStream(tmpFile)); \,E;b{PQo6  
output.writeInt(nStartPos.length); "@E1^
  
for(int i=0;i<nStartPos.length;i++) W]n%$a  
{ k"V3FXC)  
// output.writeLong(nPos); 3 $Uv  
output.writeLong(fileSplitterFetch.nStartPos); [Qv%  
output.writeLong(fileSplitterFetch.nEndPos); `{/z\  
} fdN-Zq@'  
output.close(); N@^
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} ])a?ri  
catch(IOException e){e.printStackTrace ();} ]RQQg,|D  
catch(Exception e){e.printStackTrace ();} V2'(}k  
} #T n~hnW  
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//读取保存的下载信息（文件指针位置） t}`|\*a  
private void read_nPos() 'UT 4x9&z  
{ !o&Mw:d  
try{ `yHV10  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ~^IS{
1  
int nCount = input.readInt(); /z,sM"d  
nStartPos = new long[nCount]; !w98[BE7  
nEndPos = new long[nCount]; +tOBt("5/  
for(int i=0;i<nStartPos.length;i++) s%J|r{F6  
{ r 06}@7  
nStartPos = input.readLong(); X1i6CEa<  
nEndPos = input.readLong(); :*6tbUp  
} 6A/Nlk.  
input.close(); Zcz)FP#  
} xZL`<3?  
catch(IOException e){e.printStackTrace ();} 7Z"mVh}  
catch(Exception e){e.printStackTrace ();} Lqbu]  
} W9Bl'e  
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private void processErrorCode(int nErrorCode) "a6 wd  
{ lbgnO s,  
System.err.println("Error Code : " + nErrorCode); >3X!c"#l  
} %dS7u$Rnh  
(ZjIwA9>  
?G
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//停止文件下载 .7Ys@;>B  
public void siteStop() @=b0>^\m  
{ C&3#'/&  
bStop = true; #* 
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for(int i=0;i<nStartPos.length;i++) or~o'  
fileSplitterFetch.splitterStop(); B.K"1o  
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} #v')iR"  
} X c,UR.  
//负责部分文件的抓取 ^Q4w<sX'  
**FileSplitterFetch.java 3.Qf^p  
*/ ~7b
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package NetFox; s+tS4E?  
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import java.io.*; $ZXy&?4  
import java.net.*; r['T.yo  
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public class FileSplitterFetch extends Thread { :4<+)r26  
s>"=6gb  
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String sURL; //File URL ph30/*8  
long nStartPos; //File Snippet Start Position l`gRw4/$  
long nEndPos; //File Snippet End Position Cr4shdN34  
int nThreadID; //Thread's ID IL}pVa00{n  
boolean bDownOver = false; //Downing is over +yS"pOT  
boolean bStop = false; //Stop identical e&7GW9FSg  
FileAccessI fileAccessI = null; //File Access interface ~VU
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException o]MQ)\r  
{ }%y_LcL  
this.sURL = sURL; xh@H@Q\  
this.nStartPos = nStart; t_3)}  
this.nEndPos = nEnd; zScV 9,H1  
nThreadID = id; h^~eTi;c]Q  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Otn,(j;u  
} k^]+I%?Q  
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public void run() @p|[7'  
{ KHcfP7  
while(nStartPos < nEndPos && !bStop) ^P:9iu)+]~  
{ `\q4z-<-  
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try{ s3_i5,y  
URL url = new URL(sURL); Z=R>7~H  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Trbgg  
httpConnection.setRequestProperty("User-Agent","NetFox"); =d7lrx+z  
String sProperty = "bytes="+nStartPos+"-"; zBB4lC{q  
httpConnection.setRequestProperty("RANGE",sProperty); y$*Tbzp  
Utility.log(sProperty); &>@nW!n u  
/%Rz`}  
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InputStream input = httpConnection.getInputStream(); z mrk`o~  
//logResponseHead(httpConnection); =:6Y<ftC  
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byte[] b = new byte[1024]; @XDU!<N  
int nRead; #rzxFMA"  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) R7x
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{ *J8j_-i,R  
nStartPos += fileAccessI.write(b,0,nRead); 2y ~]Uo  
//if(nThreadID == 1) WsJ3zZc  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); #R305  
} 3r+v
pyu  
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Y  
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Utility.log("Thread " + nThreadID + " is over!"); iIcO_ZyA  
bDownOver = true; "]kaaF$U%  
//nPos = fileAccessI.write (b,0,nRead); V`S6cmwdc\  
} 8
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catch(Exception e){e.printStackTrace ();} uzho>p[ae  
} H`),PY2  
} +X cB5S>  
q^([ & +  
l]T|QhiVd  
//打印回应的头信息 ZaH<\`=%  
public void logResponseHead(HttpURLConnection con) qK.8^{b  
{ jf*M}Q1jHE  
for(int i=1;;i++)  7I^(vQ  
{ G5"UhnOD'  
String header=con.getHeaderFieldKey(i); e]uk}#4  
if(header!=null) U,[vfSDGr  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ztgSd8GGE  
Utility.log(header+" : "+con.getHeaderField(header)); yew9bn0a=  
else B\KvKT|\  
break; , YTuZS  
} 1f~unb\Gg  
} o`M7:8G  
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D7[ 8*^  
public void splitterStop()  #XQEfa  
{ C[& \Xq  
bStop = true; Et
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} _;v4]MU  
b0PF7PEEQ  
{]Nvq9?  
} x}AWWmXv  
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/* Rzj5B\+Rk(  
**FileAccess.java A$;U*7TJuO  
*//文件访问(定位，写) "CT'^d+  
package NetFox; fg*IHha  
import java.io.*; p
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tL 3]9qfj  
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public class FileAccessI implements Serializable{ Cbx/  
*S:^3{.m=  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ;pBSGr9  
RandomAccessFile oSavedFile; &P&M6v+  
long nPos; Zh{Pzyp  
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public FileAccessI() throws IOException flVQG@  
{ deQ0)A 4g  
this("",0);  zy  
} 3RXq/E  
oa}-=hG  
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public FileAccessI(String sName,long nPos) throws IOException }_@*,  
{ 9=ns.r  
oSavedFile = new RandomAccessFile(sName,"rw"); U;`N:~|p#  
this.nPos = nPos; ?`uY*+u  
oSavedFile.seek(nPos); Eu l,1yR  
} (6^v`SZ  
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rs]%`"&=  
public synchronized int write(byte[] b,int nStart,int nLen) g&`e2|[7  
{ q$(aMO&J  
int n = -1; k9~NIvnB`  
try{ !L2R0Y:a  
oSavedFile.write(b,nStart,nLen); L1VUfEG-  
n = nLen; Ha[Bf*  
} brl(7_2  
catch(IOException e) r0+lH:G*q  
{ u+&BR1)C  
e.printStackTrace ();
7!]$XGz[  
} 0x4Xs  
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return n; \5_+6  
} 3 i Id>  
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} |j^^*z@  
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$.a<b^.Xi  
/* o:.={)rX  
**SiteInfoBean.java ~4
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*/ P%8 Gaa=  
package NetFox; sG=D(n1  
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public class SiteInfoBean { aqQ YU5l4~  
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private String sSiteURL; //Site's URL ZgP=maQk  
private String sFilePath; //Saved File's Path s )POtJ<  
private String sFileName; //Saved File's Name +0{m(
%i  
private int nSplitter; //Count of Splited Downloading File Qj.]I0d  
MRR5j;4GK  

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public SiteInfoBean() jV2L;APCq  
{//nSplitter的缺省值为5 6}6;%{p"Gu  
//default value of nSplitter is 5
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this("","","",5); @%d g0F}h  
} B8F.}M-!  
|L}zB,  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter)  0w>V![  
{ `O?Kftv*  
sSiteURL= sURL; V7U&8UPb  
sFilePath = sPath; )h]~< fU  
sFileName = sName; |`+kZ-M*  
this.nSplitter = nSpiltter; ]v(8i3P84  
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,m;S-Im_Xr  
} Jr$,w7tQn@  
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tJ>%Xop  
public String getSSiteURL() N:?U
A  
{ GvSSi'q~B  
return sSiteURL; mk(O..)2  
} 4y\qJw)~U  
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R4"*<%1  
public void setSSiteURL(String value) @}eEV[Lli  
{ ^,*ED Yz  
sSiteURL = value; `Fnl<C<  
} t2skg
  

!~Gx@Ro  
I@Pp[AyG  
public String getSFilePath() -sO[,  
{ sU!h^N$  
return sFilePath; 7#d>a=$h  
} cyrVz4_a  
d` %8qLIW  
^0)Mc"&{  
public void setSFilePath(String value) BmR++?L  
{ a~q_2S]h  
sFilePath = value; fFDI qX  
} O'm><a>8  
7=i8$v&GX  
wNo2$>*  
public String getSFileName() (3cJ8o>&  
{ hgIqr^N9  
return sFileName; H'KCIqo  
} \d"JYym  
h1}U#XV  
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public void setSFileName(String value) p7et>;WRx  
{ =1Nz*
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sFileName = value; aF*KY<w  
} sB!#`kh  
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6  
public int getNSplitter() W>f q 9  
{ \9"  
return nSplitter; KuBN_bd  
} 4'3do>!  
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public void setNSplitter(int nCount) 0RHKzk6~c  
{ `9;0Y  
nSplitter = nCount; LLyw9y1  
} 7egE."  
} aa|u*afWQ  
UWU(6J|Fk  
q4u,pm,@  
/* xgDd5`W  
**Utility.java 5OEo(&  
*/ a8 X}r.  
package NetFox; e"}JHXs  
4
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public class Utility { /{1sU}k-  
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A]0A
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public Utility() &10l80vj  
{ M3XG s|gw  
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} -e_91WI  
*Bfo"["0.  
//线程睡眠 \c')9g@  
public static void sleep(int nSecond) /80H.|8O  
{ ]MD,{T9l\>  
try{ zM+4<k_dH]  
Thread.sleep(nSecond); LZ#=Ks  
} pbCj ^  
catch(Exception e) EdL2t``  
{ {F!/\2a  
e.printStackTrace (); S?b^g'5m  
} TxJoN]Z.  
} m^k$Z0  
V}3'0  
//日志 tIK`/)w,  
public static void log(String sMsg) zH"a>+st=  
{ }K.Rv(m  
System.err.println(sMsg); |>^5G@e
 
} gB _/(  
1JQ5bB"  
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public static void log(int sMsg) Pj-.oS2dA  
{ G]]"Jc  
System.err.println(sMsg); ]ilQq~X  
} 1.9bU/X  
} 
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y+\kZIqX  
C/$bgK[ev  
/* s5bqS'%  
**TestMethod.java oACbZ#/@n  
*/ 6|mHu2qXm  
package NetFox; sLKk1A  
,`Keqfx  
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public class TestMethod { ?^whK<"]  
,?>{M  
NX[-Y]t  
public TestMethod() ]OSq}ul  
{ ///xx/weblogic60b2_win.exe K`=9"v'f+  
try{ HVJq
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SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Iuyq!R4:7  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ZUyS+60  
SiteFileFetch fileFetch = new SiteFileFetch(bean); z*a-=w0  
fileFetch.start(); z@g%9|U  
} f+cN'jH E  
catch(Exception e){e.printStackTrace ();} 3"BSP3/[l  
~'V&[]nh8  
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} 1[yy/v'q  
p4F%FS:`  
$:?Dyu(Il  
public static void main(String[] args) vfd<qdi3p(  
{ /0swrt.  
new TestMethod(); ~6"=d  
} {q/;G!ON.S  
} $`A{-0=x\U  
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