http断点续传简单实现（java)

/* <zm:J4&>T  
**SiteFileFetch.java ZYt1V"2VJ  
*/ _sn<"B%>  
package NetFox; eVd:C8q  
import java.io.*; kgI8PybY  
import java.net.*; NkoyEa/^[  
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public class SiteFileFetch extends Thread { +F.@n_}p-I  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ^\[c][fo  
long[] nStartPos; //开始位置 N,UUM|?9_  
long[] nEndPos; //结束位置 m6'9Id-:L  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 b7'l3mQjk  
long nFileLength; //文件长度 %{rPA3Xoy  
boolean bFirst = true; //是否第一次取文件 _SkiO}c8  
boolean bStop = false; //停止标志 9
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File tmpFile; //文件下载的临时信息 
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DataOutputStream output; //输出到文件的输出流 L={\U3 __k  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ' 6)Yf}I  
public SiteFileFetch(SiteInfoBean bean) throws IOException O{\%{XrW  
{ >cpv4Pgm  
siteInfoBean = bean; $@l=FV_;  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); l%xTF@4e  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ?op;#/Q(  
if(tmpFile.exists ()) \4>w17qng  
{ eSHsE3}h  
bFirst = false; <Mu T7x-  
read_nPos(); xel|,|*Yq  
} 5V~vND* s  
else x$t2Y<_  
{ *3
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nStartPos = new long[bean.getNSplitter()]; Kz
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nEndPos = new long[bean.getNSplitter()]; ;kWWzg  
} l*{Bz5hc  
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/ !y~Q|<|=  
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} (P=WKZMPN  
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public void run() e"*1l>g  
{ $:# :"  
//获得文件长度 4GH&u,  
//分割文件 +XSe;xk;rD  
//实例FileSplitterFetch aXzb]">  
//启动FileSplitterFetch线程 |ICn/r~  
//等待子线程返回 L8H:,} 2  
try{ `7'^y  
if(bFirst) 2h#.:!/SMw  
{ T1R~^x1  
nFileLength = getFileSize(); ~]].i~EV(  
if(nFileLength == -1) _CTg")0o  
{ ng~LCffpY  
System.err.println("File Length is not known!"); Z"qJil}  
} ^Bo'87!.  
else if(nFileLength == -2) +FAxqCkA  
{ nLmF5.&  
System.err.println("File is not access!"); o4OB xHKy  
} *]}F=dtR k  
else `'*4B_.  
{ :_]0 8  
for(int i=0;i<nStartPos.length;i++) MppT"t  
{ z}B8&*>  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); {'[VL;k  
} V;^N:I\js  
for(int i=0;i<nEndPos.length-1;i++) FFcIOn  
{ >56fa6=3@  
nEndPos = nStartPos[i+1]; WW+F9~S  
} XR3 dG:  
nEndPos[nEndPos.length-1] = nFileLength; >I<}:=  
} I3b*sx$  
} uMpuS1  
+IWf~|s  
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//启动子线程 p_%,JD  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; SAj#+_db  
for(int i=0;i<nStartPos.length;i++) cNFHbMd  
{ j
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fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ; yE.R[I  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), WPrBK{B`o  
nStartPos,nEndPos,i); E:k]Z  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); e igVT4  
fileSplitterFetch.start(); ^*+M9e9Z  
} z@o6[g/*Q  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), (C1~>7L  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); CE!cZZ  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", >,tJq%  
nEndPos = " + nFileLength); bfEH>pQ>#  
// fileSplitterFetch[nPos.length-1].start(); $7]?P;$  
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xIW]e1pu=(  
//等待子线程结束 a7uL{*ZR  
//int count = 0;
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//是否结束while循环 _Pa@%/  
boolean breakWhile = false; \jV2":[%c  
9<iM2(IW{  
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while(!bStop) &j ;91wEn  
{ 7E#h(bt j  
write_nPos(); 7'65+c[&  
Utility.sleep(500); "EA =auN{  
breakWhile = true; C[hNngb7R  
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j
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for(int i=0;i<nStartPos.length;i++) L+T'TC:  
{ =hd0Ui>x  
if(!fileSplitterFetch.bDownOver) N6p
0`
 
{ TQ:e! 32  
breakWhile = false; I Z*)  
break; 3-6M
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} zY@0R`{@p  
} I$x<B7U  
if(breakWhile) +-SO}P  
break; ^c/3!"wK  
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//count++; %X^qWKix}m  
//if(count>4) vJct)i  
// siteStop(); | oM`  
} 2A =Y  
(CH6Q]Wi_!  
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System.err.println("文件下载结束！"); !>ZBb\EyK  
} %K8YZc(&  
catch(Exception e){e.printStackTrace ();} R.l
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} &iq'V*+-\  
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8.^`~ta  
//获得文件长度 hR:i!  
public long getFileSize() ]Ol w6W?%  
{ \6.dGKK  
int nFileLength = -1; .I]v D#o  
try{ {~R?f$}""j  
URL url = new URL(siteInfoBean.getSSiteURL()); GUM-|[~  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Wd(|w8J{a  
httpConnection.setRequestProperty("User-Agent","NetFox"); \fSruhD  
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int responseCode=httpConnection.getResponseCode(); VKu_l  
if(responseCode>=400) <0hVDk~  
{ ubsv\[:C  
processErrorCode(responseCode); 7bE`P[  
return -2; //-2 represent access is error >gq=W5vN(  
} $G}k'[4C  
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String sHeader; Er8F_,M+  
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for(int i=1;;i++) Xt:j~cVA  
{ lA4J#  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 38l:Y"  
//Utility.log(in.readLine());  xiQc\k$  
sHeader=httpConnection.getHeaderFieldKey(i); "?<`]WG\  
if(sHeader!=null) /#"9!8%V  
{ yLnTIE3)  
if(sHeader.equals("Content-Length")) X}h}3+V  
{ fpjFO&ML  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); .wWf#bB  
break; 8@rF~^-_  
} .#a7?LUH  
} OI:=>Bk  
else 0$Zh4Y  
break; )@y'$)5s  
} NU{eoqaT  
} 0pB'^Q{  
catch(IOException e){e.printStackTrace ();} P@n rcgM.  
catch(Exception e){e.printStackTrace ();} 3BLHd<  
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Utility.log(nFileLength); 5^l-3s?M  
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return nFileLength; dvY3=~'  
} i!JSEQ_8  
'&gUAt  
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//保存下载信息（文件指针位置） $(OL#>9Ly  
private void write_nPos() G%i&C)jZ  
{ !^1oH*
*  
try{ @^-f+o  
output = new DataOutputStream(new FileOutputStream(tmpFile)); }095U(@  
output.writeInt(nStartPos.length); nHfAx/9!  
for(int i=0;i<nStartPos.length;i++) h]
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{ i1b3>H*3  
// output.writeLong(nPos); u8<Fk !  
output.writeLong(fileSplitterFetch.nStartPos); uV'C_H  
output.writeLong(fileSplitterFetch.nEndPos); **6X9ZIX[  
} eUgKwu;  
output.close(); xs"\c7pC  
} 6 {3ql:  
catch(IOException e){e.printStackTrace ();} 9NU-1vd~  
catch(Exception e){e.printStackTrace ();} RJN LcIm  
}  Spo[JQ%6  
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#0#
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//读取保存的下载信息（文件指针位置） %F;uW[4r  
private void read_nPos() NB( G
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{ (~b0-3s  
try{ jt9@aN.mJN  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); xFp9H'j{  
int nCount = input.readInt(); "68=dC  
nStartPos = new long[nCount]; A/j'{X!z  
nEndPos = new long[nCount]; 1ahb:Mjv  
for(int i=0;i<nStartPos.length;i++) XFww|SG$  
{ $uK[[k~=S  
nStartPos = input.readLong(); PbMvM  
nEndPos = input.readLong(); W%9"E??c  
} 5(Xq58nhxI  
input.close(); 9w\C vO&R  
} 5y~B/.YY  
catch(IOException e){e.printStackTrace ();} 1py>[II@  
catch(Exception e){e.printStackTrace ();} %.{xo.`a[  
} zKG]7  
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private void processErrorCode(int nErrorCode) U/rFH9e$  
{ ,/Y$%.Rp  
System.err.println("Error Code : " + nErrorCode); _
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} 
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//停止文件下载 -N2m|%B  
public void siteStop() -PiZvge  
{ ZQ#AEVI,  
bStop = true; cW^u4%f't'  
for(int i=0;i<nStartPos.length;i++) 3+D4$Y"  
fileSplitterFetch.splitterStop(); |q_Hiap#a  
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} :Ui'x8yt  
} u$x'P <b  
//负责部分文件的抓取 o-]8)G>~M  
**FileSplitterFetch.java o1<Z;2#  
*/ Xkp`1UTH  
package NetFox; ]#$rTWMl'  
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import java.io.*; ]5eZLXM  
import java.net.*; yfe4}0}  
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public class FileSplitterFetch extends Thread { bLz('mUY  
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String sURL; //File URL t~]tw  
long nStartPos; //File Snippet Start Position 3W?H^1t  
long nEndPos; //File Snippet End Position DEpn>   
int nThreadID; //Thread's ID =,W~^<\"  
boolean bDownOver = false; //Downing is over 8';huq@C{  
boolean bStop = false; //Stop identical [\ppKC  
FileAccessI fileAccessI = null; //File Access interface JB!KOzw  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException N*>&XJ#  
{ IeE6?!,)  
this.sURL = sURL; T7Xbb
U  
this.nStartPos = nStart; D4QLlP  
this.nEndPos = nEnd; A4VVy~sd  
nThreadID = id; zLVk7u{e  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 :}fIu?hCA  
} "NO*(<C.R  
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public void run() bRc~e@  
{ [Z+E_Lbz  
while(nStartPos < nEndPos && !bStop) (0bX
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{ Jd/XEs?<q  
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try{ 1VO>Bh.Wm  
URL url = new URL(sURL); g6<D 1r  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); [ST7CrwC  
httpConnection.setRequestProperty("User-Agent","NetFox"); VaylbYUCT/  
String sProperty = "bytes="+nStartPos+"-"; }kb6;4>c
 
httpConnection.setRequestProperty("RANGE",sProperty); 14rX:z  
Utility.log(sProperty); [c#?@S_  
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InputStream input = httpConnection.getInputStream(); o_%gFV[q  
//logResponseHead(httpConnection); 'tzN.p1O  
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G!m;J8#m(  
byte[] b = new byte[1024]; NpxND0  
int nRead; ~-2q3U Py  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) >WW5;7$  
{ e5.sqft  
nStartPos += fileAccessI.write(b,0,nRead); 1FmqNf:V7I  
//if(nThreadID == 1) eop7=!`-~~  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); C2Af$7c  
} cP(is!  
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Utility.log("Thread " + nThreadID + " is over!"); LDq(WPI1#  
bDownOver = true; &$E.rgtg  
//nPos = fileAccessI.write (b,0,nRead); )u(Dqu\t  
} bmGtYv  
catch(Exception e){e.printStackTrace ();} Ewczq1%l:  
} 5_Opx=  
} ALnE[}N6,  
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"+KAYsVtU  
//打印回应的头信息 /s~&$(d59o  
public void logResponseHead(HttpURLConnection con) c9N5c  
{ e't1.%w  
for(int i=1;;i++) !mRDzr7  
{ 3k?|-js  
String header=con.getHeaderFieldKey(i); XYsU)(;j  
if(header!=null) !V;glx[  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); >>HC|  
Utility.log(header+" : "+con.getHeaderField(header)); >qjV(_?F-  
else [i)G:8U  
break; 9jTm g%  
} Z }Z]["q  
} *f( e`3E  
}=JuC+#~n  
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public void splitterStop() ?513A>U  
{ Cu+u'&U!  
bStop = true; M-+=t8  
} nfzKUJY  
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07tSXl5!  
} b_j8g{/9  
23=SXA!  
,}_uk]AQ  
/* \Zms  
**FileAccess.java #mcU);s  
*//文件访问(定位，写) dX:#KdK  
package NetFox; maTZNzy  
import java.io.*; _Zs]za.#)|  

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p?zh4:\F+  
public class FileAccessI implements Serializable{ C1KO]e>  
-$m?ShDd  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ^L;k  
RandomAccessFile oSavedFile; Q.Ljz Z  
long nPos; &SE+7HXw  
5!)_"u3  
!2Q>  
public FileAccessI() throws IOException 9F"Q2^l'  
{ /*yPy?  
this("",0); L=WB'*N  
} @n:.D9  
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9  
6$^dOJ_"  
public FileAccessI(String sName,long nPos) throws IOException H0.,h
;  
{ }8cX0mZ1j  
oSavedFile = new RandomAccessFile(sName,"rw"); gELb(Y\ak  
this.nPos = nPos; <"XDIvpc%L  
oSavedFile.seek(nPos); F"M$ "rC]  
} %/x%hs;d  
znl_~:.4]X  
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public synchronized int write(byte[] b,int nStart,int nLen) N$SJK  
{ !,3U_!  
int n = -1; ^ M4-O~  
try{ ~ U,a?LR/  
oSavedFile.write(b,nStart,nLen); kwd)5J  
n = nLen; h*GU7<F:a  
} AE"E($S`  
catch(IOException e) L/R ES  
{ kbkq
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e.printStackTrace (); |r=.}9 -  
} ib%x&?||  
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return n; pD>^Dfd  
} "gP
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MjHjL~Tg  
} )d|hIW]7(  
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SLze) ?.  
/* ?)~j>1"S  
**SiteInfoBean.java $ (gR^L  
*/ @GiR~bKZ  
package NetFox; D< 4!7*9%  
%aszZP  
:9E_L2M  
public class SiteInfoBean { 5vso%}c  
FiQx5}MMhu  
5E+k}S]M$  
private String sSiteURL; //Site's URL KQ x<{-G6  
private String sFilePath; //Saved File's Path +i[w& P  
private String sFileName; //Saved File's Name Xkv+"F=-  
private int nSplitter; //Count of Splited Downloading File Qb|.;_  
CXsi  
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public SiteInfoBean() S}hg*mWn{$  
{//nSplitter的缺省值为5 nd]AvVS  
//default value of nSplitter is 5 7BX%z$_)A  
this("","","",5); {:3XP<hqN  
} (1vmtg.O  
CKTD27})  
0CD2o\`8  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) G"BoD5m  
{ ):_x  
sSiteURL= sURL; "p\XaClpz  
sFilePath = sPath; >)N}V'9  
sFileName = sName; Mlpq2I_x  
this.nSplitter = nSpiltter; _5nQe !  
"F+Wo&  
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} %V$ujun`  
N!fp;jvG  
TLL.Ch|#Y  
public String getSSiteURL() e< Ee2pGX  
{ Z6cG<,DQ  
return sSiteURL;
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} (8r?'H8ZO  
[)gvP'  
6wWA(![w"  
public void setSSiteURL(String value) k*4?fr  
{ o4kNDXP#S  
sSiteURL = value; m,u? ^W  
} >oc7=F<8lS  
Lh &L5p7  
c3lfmTT6^  
public String getSFilePath() |yI?}zyR  
{ ^yRCR] oT  
return sFilePath; WPE@yI(  
}  \~  
RU`TzD  
 FFgy=F  
public void setSFilePath(String value) Jz#ZDZkm  
{ qi7wr\XNW  
sFilePath = value; is}Fy>9i  
} na FZ<'t>&  
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$ZDh8 *ND  
public String getSFileName() Iw"?%k\U  
{ }
}qR~.[  
return sFileName; 8IC((  
} nm'm*sU\  
t:M({|m Y  
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public void setSFileName(String value) #k=!>%+E  
{ f|VP_o<  
sFileName = value; CRWO R pP  
} )m[!HE`cZ  
PyHE>C%  
!*%3um  
public int getNSplitter() !9o8v0ZI  
{ )K2n!Fbd  
return nSplitter; NUL~zb  
} #G#gB   
O!f*@  
]?)zH:2)  
public void setNSplitter(int nCount) PJAir8  
{ m$J'nA  
nSplitter = nCount; rI]:| k  
} )KRO=~Y  
} q#\eL~k  
WaMn
[/{  
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/* Iz{AA-  
**Utility.java ((dG<  
*/ c
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package NetFox; 0t4i'??  
6!Isz1.re  
N7#GK]n%/}  
public class Utility { gdC=SFb b  
)QZ?Bf  
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public Utility() fQx 4/4j  
{ R4qk/@]t  
DTIy/  
5?vIkf  
} j#p3
c  
G#% =R`k/  
//线程睡眠 56':U29.]  
public static void sleep(int nSecond) Nq~bO_-I  
{ kD;BwU[  
try{ ]c5GG!E-g  
Thread.sleep(nSecond); orU4{.e  
} 1g/mzC
  
catch(Exception e) Bv=Z*"Fv  
{ rfPJBD{Ve  
e.printStackTrace (); *pWswcV/  
} !E7/:t4  
} Ta[}k/zW  
@/7Rp8Fr  
//日志 "{0kg'fU  
public static void log(String sMsg) 3S5Qq
Am  
{ /r?X33D!  
System.err.println(sMsg); E{Q^ZSV3B  
} ZK'I$p]b  
03#_ (  
yz+r@I5  
public static void log(int sMsg) uC;@Yi8  
{ ss2:8up 99  
System.err.println(sMsg); 6% ,Q  
} 9SFiL#1  
} %Bo Jt-v  
):[[Ch_  
$Y4 Ao-@  
/* TMRXl.1  
**TestMethod.java G![1+2p:Tq  
*/ \m.{^Xd~  
package NetFox; 0bd.e
ss  
0s4j>  
^Ta"Uk'  
public class TestMethod { 1IsR}uLh  
FQ4rA 4  
0+H"$2/  
public TestMethod() {l1;&y?  
{ ///xx/weblogic60b2_win.exe hmi15VW  
try{ [j/-(?+  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); (nzzX?`nY  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); l:[=M:#p  
SiteFileFetch fileFetch = new SiteFileFetch(bean); N!va12  
fileFetch.start(); [lJ[kr*7  
} bBQp:P?E  
catch(Exception e){e.printStackTrace ();} bIhL!Ty T.  
+*!!  
RcE%?2lD  
} ]zm6;/S  
2-CK:)n/#  
2]'ozs$|v  
public static void main(String[] args) w])Sz*J  
{ &S{F"z  
new TestMethod(); oc?VAF  
} &KB{,:)?  
} U9q*zP_jV  
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