http断点续传简单实现（java)

/* |P~TZ  
**SiteFileFetch.java keCM}V`?"  
*/ 6fQQKM@a|  
package NetFox; h<.&,6R  
import java.io.*; \%rX~UhZ=  
import java.net.*; ;v>2z!M  
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public class SiteFileFetch extends Thread { BWz*!(   
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SiteInfoBean siteInfoBean = null; //文件信息Bean 8@Y]dzgjj  
long[] nStartPos; //开始位置 
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long[] nEndPos; //结束位置 ~B|K]&/]  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 c?j/H$  
long nFileLength; //文件长度 &F)P3=  
boolean bFirst = true; //是否第一次取文件 pz#oRuujY  
boolean bStop = false; //停止标志 ->$Do$  
File tmpFile; //文件下载的临时信息 )Q&:$]  
DataOutputStream output; //输出到文件的输出流 `A3"*,|z
 
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） E0Ig/ j  
public SiteFileFetch(SiteInfoBean bean) throws IOException S0,p:Wey  
{ `a98+x?JF  
siteInfoBean = bean; @e3O=_m-  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); =P-kb^s  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); $5s?m\!jZz  
if(tmpFile.exists ()) ^4h/6^b0c  
{ M&:[3u-  
bFirst = false; +t,JCY6  
read_nPos(); tNG0ft%a  
} K;k&w; j  
else I?EtU/AD  
{ (O"Wa  
nStartPos = new long[bean.getNSplitter()]; 9jCn|+  
nEndPos = new long[bean.getNSplitter()]; pa`"f&JO  
} "+~La{POc  
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} OB.TAoH:  
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public void run() a;r,*zZ="  
{ Lf4c[[@%gd  
//获得文件长度 dmgoVF_qR  
//分割文件 [u`v'*0d  
//实例FileSplitterFetch o $7:*jU  
//启动FileSplitterFetch线程 ?suxoP%  
//等待子线程返回 ^7G@CBi
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try{ z'z_6]5  
if(bFirst) U(4>e!  
{ 2_'{f1bVxz  
nFileLength = getFileSize(); ANR?An  
if(nFileLength == -1) 1MkQ$v7m  
{ F=?0:2P0bD  
System.err.println("File Length is not known!"); 0<d9al|J  
} C2OBgM+  
else if(nFileLength == -2) ,U
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{ (,*e\o  
System.err.println("File is not access!"); :08b&myx  
} J$Uj@M  
else 
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{ U.g7'`Z<  
for(int i=0;i<nStartPos.length;i++) xn|M]E1)  
{ =BW;n]ls  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); }TfZ7~o[  
} .dM4B'OA?  
for(int i=0;i<nEndPos.length-1;i++) $2I^ ;5r[  
{ %P@V7n  
nEndPos = nStartPos[i+1]; zmaf@T
 
} h\dq]yOl  
nEndPos[nEndPos.length-1] = nFileLength; wyWe2d  
} *f<+yF{=A  
} X0G6Wp  
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"Bn8WT2?  
//启动子线程 $o}Ao@WkO  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; >(T)9
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for(int i=0;i<nStartPos.length;i++) pe%$(%@v  
{ `_"F7Czn  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), F%|F-6  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), :qlc
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nStartPos,nEndPos,i); T'C^,,if  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); r2!\Ts5v  
fileSplitterFetch.start(); b~oQhU??"  
} Uphme8SX  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 'tyblj C  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); K3g<NC  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", g_8A1lt  
nEndPos = " + nFileLength); #
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// fileSplitterFetch[nPos.length-1].start(); '\g-z  
<?8aM7W7  
2&b?NqEeZ  
//等待子线程结束 ;-]' OiS;  
//int count = 0; "|k 4<"]  
//是否结束while循环 "2m (*+  
boolean breakWhile = false; ."X}A t  
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|J:|56kVZq  
while(!bStop) kMS&"/z  
{ IJ[r!&PY  
write_nPos(); h&|PHI  
Utility.sleep(500); oeKVcVP|'&  
breakWhile = true;
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for(int i=0;i<nStartPos.length;i++) n5qg6(Tl]  
{ 6,~Y(#  
if(!fileSplitterFetch.bDownOver) fV(WUN+  
{ ovXU +8  
breakWhile = false; 4it^-M  
break; s;!_'1pi@  
} 4AWL::FU5  
}
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if(breakWhile) ye^*Z>|  
break; u5Tu~  
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//count++; gVscdg5  
//if(count>4) 1OI/,y8}  
// siteStop(); h<0&|s*a)  
} &02I-lD4+  
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System.err.println("文件下载结束！"); \?_M_5Nb  
} }nx5  
catch(Exception e){e.printStackTrace ();} N|5fkx<d^  
} b2r]>*Vc  
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`
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//获得文件长度 xg;I::hE7X  
public long getFileSize() 3YO%$  
{ % B^BN|r  
int nFileLength = -1; F%ffnEJg  
try{ oAprM Z7Y  
URL url = new URL(siteInfoBean.getSSiteURL()); X#Sgf|$  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ]tx/t^&/\u  
httpConnection.setRequestProperty("User-Agent","NetFox"); %M5{-pJ|C  
or qL0i  
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int responseCode=httpConnection.getResponseCode(); 'ju'O#A9  
if(responseCode>=400) ,^1B"#0{C<  
{ #V$h?`qhwr  
processErrorCode(responseCode); @L,4JPk  
return -2; //-2 represent access is error [pxC3{|d$  
} #ZyY(S1.  
 SH6+'7  
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String sHeader; b*)F7{/Z  
,(3oAj\  
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for(int i=1;;i++) Tf40lv+{  
{ +5x{|!Pn  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); "lRxatM  
//Utility.log(in.readLine()); \C<'2KZR,  
sHeader=httpConnection.getHeaderFieldKey(i); QV[#^1  
if(sHeader!=null) L\zyBfK}  
{ G{74o8  
if(sHeader.equals("Content-Length")) hem>@Bp'V  
{ A5E^1j}h@  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); B9dc*  
break; h?Lp9VF  
} VA5f+c
/ %  
} 2. q\!V}yQ  
else j6WDh}#  
break; K=1prv2  
} _<%YLv  
} O>"T*   
catch(IOException e){e.printStackTrace ();} Vg(FF"  
catch(Exception e){e.printStackTrace ();} ^'p!#\T;H  
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;}H*|"z;!  
Utility.log(nFileLength); ?G[=pY:=  
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{>Hn:jW<.  
return nFileLength; 3 MCV?"0  
} mu2|%$C;$  
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//保存下载信息（文件指针位置） d&lT/S  
private void write_nPos() E/<n"'0ek  
{ h_Ssm{C\  
try{ z.|[g$F  
output = new DataOutputStream(new FileOutputStream(tmpFile)); hU3sEOm>  
output.writeInt(nStartPos.length); &4wwp!J  
for(int i=0;i<nStartPos.length;i++) i|rCGa0}  
{ Lvrflx*Q  
// output.writeLong(nPos); JS/~6'uB  
output.writeLong(fileSplitterFetch.nStartPos); \opcn\vW  
output.writeLong(fileSplitterFetch.nEndPos); A;k#8&;  
} ;9<?~S  
output.close(); Yx&d\/9  
} #qARcxbK|  
catch(IOException e){e.printStackTrace ();} b2H-D!YO^  
catch(Exception e){e.printStackTrace ();} kQp*+ras  
} 2UIZ<#|D>s  
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//读取保存的下载信息（文件指针位置） 3:)_oHq  
private void read_nPos() uPC(|U%  
{ n5#QQk2  
try{ |h\A5_0_  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); RXo6y(^  
int nCount = input.readInt(); =?_:h`}  
nStartPos = new long[nCount]; >[&ser  
nEndPos = new long[nCount]; 2Da0*xn{  
for(int i=0;i<nStartPos.length;i++) bM2x (E\
O  
{ ?M^qSo=/~  
nStartPos = input.readLong(); v(6[z)A0  
nEndPos = input.readLong(); RY3=UeoF  
} =:t<!dp  
input.close(); @NL37C  
} #M<YNuE#"  
catch(IOException e){e.printStackTrace ();} m2&Vm~Py6b  
catch(Exception e){e.printStackTrace ();} D2J)qCK1)  
}  vY"I  
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private void processErrorCode(int nErrorCode) _~'M
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{ WJI}~/z;C  
System.err.println("Error Code : " + nErrorCode); pNZ3vTs6  
} r;{ggwY&J  
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//停止文件下载 2b
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public void siteStop() C,%Dp0  
{ J1w3g,  
bStop = true; Udf\;G@  
for(int i=0;i<nStartPos.length;i++) VbTX;?  
fileSplitterFetch.splitterStop(); 0d+b<J,  
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} feH&Ug4?G  
} Ujqnl>l  
//负责部分文件的抓取 ;#+I"Ow  
**FileSplitterFetch.java EQk omjv  
*/ 4sX?O4p  
package NetFox; _zzT[}  
:fnJp9c  
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import java.io.*; gPA8A
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import java.net.*; vbX.0f "n  
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public class FileSplitterFetch extends Thread { _/
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_|4QrZ$n(  
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String sURL; //File URL WnU2.:  
long nStartPos; //File Snippet Start Position mKyF<1,m  
long nEndPos; //File Snippet End Position S,udpQ7  
int nThreadID; //Thread's ID ^UhqV"[7k  
boolean bDownOver = false; //Downing is over Wb#<ctM>  
boolean bStop = false; //Stop identical I[gPW7&S@  
FileAccessI fileAccessI = null; //File Access interface c6=XJvz  
:7X{s4AU6  
{.0I!oWv  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException @HnahD  
{ [Jjo H1E@  
this.sURL = sURL; Cs,Cb2[  
this.nStartPos = nStart; qsN_EMgbdn  
this.nEndPos = nEnd; ydRS\l  
nThreadID = id; \VI0/G)L
 
fileAccessI = new FileAccessI(sName,nStartPos);//定位 gNZ"Kr o6  
} T,Q7 YI  
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public void run() ;PqC*iz  
{ ~(NFjCUY?  
while(nStartPos < nEndPos && !bStop) E7.{SGH}  
{ Uqx@9z(  
bE=[P}E  
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try{ 1W-kZ(e  
URL url = new URL(sURL); m;IKV,  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 7|bBC+;(  
httpConnection.setRequestProperty("User-Agent","NetFox"); 0LIXkF3^1  
String sProperty = "bytes="+nStartPos+"-";  BPKrRex  
httpConnection.setRequestProperty("RANGE",sProperty); q$s)(D  
Utility.log(sProperty); Yt_t>  
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InputStream input = httpConnection.getInputStream(); hYA1N&yz@  
//logResponseHead(httpConnection); HCYy9  
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byte[] b = new byte[1024]; Uxe]T  
int nRead; Y(ClG*6 ++  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) "]=XB0)  
{ \q^dhY>)  
nStartPos += fileAccessI.write(b,0,nRead); d7x6r3J$  
//if(nThreadID == 1) ycEp,V;[Z  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); CG J_k?h  
} zP@\rZ@4  
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Utility.log("Thread " + nThreadID + " is over!"); \[8uE,=|  
bDownOver = true; Xg;<?g?k  
//nPos = fileAccessI.write (b,0,nRead); @00&J~D  
} 0&Iu+hv  
catch(Exception e){e.printStackTrace ();} =NPo<^Lae  
} >Il{{{\>  
} "
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~  
 3L4v@  
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//打印回应的头信息 6$csFW3R  
public void logResponseHead(HttpURLConnection con) K!-iDaVI  
{ B7%m7GM  
for(int i=1;;i++) ZKB27D_vg>  
{ ,ob)6P^rw  
String header=con.getHeaderFieldKey(i); >{0,dGm  
if(header!=null) uw`J5TND  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); \@^` G  
Utility.log(header+" : "+con.getHeaderField(header)); C6D Eq>v  
else <#T#+uO  
break; -9s&OKo`({  
} Q[aBxy (  
} K2tOt7M!  
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,
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public void splitterStop() ;M*G  
{ HLq2avs\  
bStop = true; P4s,N|bs`  
} ^Uik{x  
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} Y}r UVn  
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 '^,|8A2  
/*  `EVy  
**FileAccess.java iR'Pc3  
*//文件访问(定位，写) KFM)*Icg\8  
package NetFox; [R/'hH5  
import java.io.*; {9nH#yv  
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public class FileAccessI implements Serializable{ ^'hh?mL  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 1@^*tffL:  
RandomAccessFile oSavedFile; @$o^(my  
long nPos; L:UPS&)  
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public FileAccessI() throws IOException "J%dI9tM{  
{ vu_ u\2d  
this("",0); 7JLjA\k
  
} a,?u 2  
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public FileAccessI(String sName,long nPos) throws IOException Z$Vd8U;  
{ 2U'Vq  
oSavedFile = new RandomAccessFile(sName,"rw"); OUtMel_
 
this.nPos = nPos;
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oSavedFile.seek(nPos); WCwM+D  
} [xl+/F7  


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public synchronized int write(byte[] b,int nStart,int nLen) aHSl_[  
{ 7DWHADr  
int n = -1; e!1am%aE  
try{ )'ax
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oSavedFile.write(b,nStart,nLen); 7\EY&KI"0  
n = nLen; k6^!G"  
} >~rytg]f  
catch(IOException e) ew|e66Tw$  
{ c7t.  
e.printStackTrace (); h0zv@,u  
} 78FLy7  
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return n; c"`CvQO64  
} Ag0)> PD^  
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} U$=#yg2 :  
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/* oO&R3z
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**SiteInfoBean.java 2#xz,RM.  
*/
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package NetFox; Ae_:Kc6  
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w ;xbQZ|+  
public class SiteInfoBean { G^qt@,n$;  
9]PMti  
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private String sSiteURL; //Site's URL @XN|R  
private String sFilePath; //Saved File's Path .[C@p`DZ  
private String sFileName; //Saved File's Name sJ5Ws%q  
private int nSplitter; //Count of Splited Downloading File cX4I+Mf  
%SN"<O!  
s1%th"e [  
public SiteInfoBean() tu5T^"BqO  
{//nSplitter的缺省值为5 1Y(NxC0P=g  
//default value of nSplitter is 5 =R
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this("","","",5); c,FZ{O@  
} agp7zw=N  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 'QC'*Hl  
{ kKz>
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sSiteURL= sURL; B2l5}"{`  
sFilePath = sPath; ,qT+Vqpr{  
sFileName = sName; ';KWHk8C  
this.nSplitter = nSpiltter; {YF(6wVl  
_o'a|=Osx>  
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} YWF Hv@  
Y4{/P1F  
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public String getSSiteURL() XS=f>e1<W  
{ W}'l8z]   
return sSiteURL; g<g$c<sm  
} {wv
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public void setSSiteURL(String value) UT_kw}1o  
{ <HH\VG\H6  
sSiteURL = value; V)A7q9Bum  
} q0L\{  
RwUosh\W  
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public String getSFilePath() 1'f&  
{ ;e0-FF+  
return sFilePath; (Rh$0^)A  
} G.]'pn  
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public void setSFilePath(String value) %\T#Ik~3  
{ L [&|<<c  
sFilePath = value; Egmp8:nZl@  
} 13fyg7^JP  
SvQ!n4 $  
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w  
public String getSFileName() M}]4tAyT  
{ KzQuLD(e  
return sFileName; ^ddC a  
} yM('!iG*/  
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public void setSFileName(String value) ]z8Th5a?o  
{ jHk.]4&0  
sFileName = value; -J>f,zA  
} >4bWXb'S}C  
%E[ $np>  
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public int getNSplitter() !m8T< LtMl  
{ N?IdaVLj  
return nSplitter; N ;Cs? C  
} Z-3("%_$/  
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^%O$7*  
public void setNSplitter(int nCount) C!Jy
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{ *onVG5<  
nSplitter = nCount; NfZC}  
} 9M-W 1prb  
} b^A7R{G7  
3gYtu-1  
r,q.RWuII  
/* 
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**Utility.java =.l>Uw!  
*/ F^&@[k7WW  
package NetFox; D;z!C ys  
P MI?PC[;  
8%p+:6kP5  
public class Utility { G=l:v  
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public Utility() Gp=V%w\FDW  
{ r@PVSH/  
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} &3SmTg %  
NTSIClm}U
 
//线程睡眠 bK{ VjXF  
public static void sleep(int nSecond) $01~G?:]`  
{ i=&]%T6Qk  
try{ HkY#i;%N  
Thread.sleep(nSecond); ru|*xNXKgC  
} rr>6;  
catch(Exception e) 5Q:%f  
{ CZ>Ujw=&k  
e.printStackTrace (); {XV'C@B  
} olKM0K  
} @z:E]O}  
+G+1B6S  
//日志 Cxe(iwa.
 
public static void log(String sMsg) C=2DxdZG  
{ rC_saHo>#R  
System.err.println(sMsg); K[x=knFO   
} $LcMG,8%_  
A`"?~_pHC  
B ]sVlbt  
public static void log(int sMsg) /SyAjZ  
{ 4J?\JcGs  
System.err.println(sMsg);  ?$y/b}8  
} 50a';!H  
} BB_(!omq[  
:Ys ;)W+R  
BqDsf5}jpA  
/* 9<kMxtk$  
**TestMethod.java JIqg[Mao  
*/ t;u)_C,bmP  
package NetFox; L+eK)Q  
 m3^D~4  
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public class TestMethod { 1QnaZhu'  
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n xR\tBv  
public TestMethod() T0.sL9  
{ ///xx/weblogic60b2_win.exe _>r(T4}]  
try{ r;E5e]w*-  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Ndyo)11z
 
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); lR
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SiteFileFetch fileFetch = new SiteFileFetch(bean); }SyK)W5Y  
fileFetch.start(); Y kvEQ=  
} ~yV?*"Hi  
catch(Exception e){e.printStackTrace ();} edZBQmx+#  
ln":j?`  
9
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} Qz_4Ms<o  
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public static void main(String[] args) fhNJB0  
{ Ekh)l0 l  
new TestMethod(); zAev@+.ld  
} x?od_M;*8;  
} DF-.|-^9I  
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