http断点续传简单实现（java)

/* 1P(|[W1  
**SiteFileFetch.java jq+A-T}@  
*/ Gkp<o  
package NetFox; dlG=Vq&Y  
import java.io.*; c wOJy>  
import java.net.*; $*kxTiG!
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public class SiteFileFetch extends Thread { 9Ffp2NW`;  
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SiteInfoBean siteInfoBean = null; //文件信息Bean !vk|<P1  
long[] nStartPos; //开始位置 mWyqG*-Hb  
long[] nEndPos; //结束位置 %~jkB.\* )  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 <D::9c j  
long nFileLength; //文件长度 H_0/f8GwnG  
boolean bFirst = true; //是否第一次取文件 RKPD4e>%  
boolean bStop = false; //停止标志 |U_]vMq  
File tmpFile; //文件下载的临时信息 -CRQ&#p1]  
DataOutputStream output; //输出到文件的输出流 gq"gUaz  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） a\%xB >LX  
public SiteFileFetch(SiteInfoBean bean) throws IOException |gsE2vV  
{ [p2H=  
siteInfoBean = bean; ~j-cS J3  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); +Y V|ij  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); o,xxh  
if(tmpFile.exists ()) h(F<h_  
{ =i(?deR  
bFirst = false; QMsHC%l3b  
read_nPos(); 2CzaL,je[  
} AQc,>{Lm  
else ?X5]i#j[  
{ ki{3IEOr}  
nStartPos = new long[bean.getNSplitter()]; z.CywME<)t  
nEndPos = new long[bean.getNSplitter()]; YG8>czC  
} >y}M.Mm  
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} UK{irU|\  
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|Xw/E)jA  
public void run() &<+ A((/i  
{ 3mSXWl^?  
//获得文件长度 PC qZNBN  
//分割文件 (D 9Su^:1  
//实例FileSplitterFetch $-&BB(-{E&  
//启动FileSplitterFetch线程 #
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//等待子线程返回 [y0O{,lI  
try{ Dk='+\  
if(bFirst) sO5?aB&  
{ jn:
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nFileLength = getFileSize();
@
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if(nFileLength == -1) Hk7q{`:N  
{ zz^F k&  
System.err.println("File Length is not known!"); k64."*X  
} JMCW}bA  
else if(nFileLength == -2) qiZO _=0  
{ gh>>Ibf  
System.err.println("File is not access!"); 1lsLJ4P  
} IQ!\w-  
else gaf$uT2  
{ /1 RAAa  
for(int i=0;i<nStartPos.length;i++) \V>?Do7  
{ x)UwV  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); !J=sk4T  
} 4HAp{
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for(int i=0;i<nEndPos.length-1;i++) ||zb6|7I4  
{ h!#:$|Q  
nEndPos = nStartPos[i+1]; J|3E-p\o  
} 0oh]61gC  
nEndPos[nEndPos.length-1] = nFileLength; i%{3W:!4t  
} Z--@.IYoJ  
} #UtFD^h  
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//启动子线程 $HG}[XD?  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; fA=#Fzk2  
for(int i=0;i<nStartPos.length;i++) ?DH"V7bs  
{ '&99?s`u  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), KIeT!kmDl  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 5*\\J&H  
nStartPos,nEndPos,i); kSc{^-<R  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ^ZM0c>ev=l  
fileSplitterFetch.start(); +p8BGNW,  
} P"lBB8\eku  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Fxc)}i`   
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); dDDGM:]  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", kF;5L)o  
nEndPos = " + nFileLength); X1tXqHJF}  
// fileSplitterFetch[nPos.length-1].start(); t |W)  
Jd,)a#<j  
f1PN|  
//等待子线程结束 >\ u<&>i  
//int count = 0; }YOL"<,:o  
//是否结束while循环 S?{/hy  
boolean breakWhile = false; .d?%;2*{q  
Eh|.  
K\^ 0_F K  
while(!bStop) l/
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{ 0GDvwy D1  
write_nPos(); muW!xY  
Utility.sleep(500); I5AO?BzJ  
breakWhile = true; T<-=nX  
y[@\j9Hq  
93IFcmO.H@  
for(int i=0;i<nStartPos.length;i++) H +bdsk  
{ idRD![!UI  
if(!fileSplitterFetch.bDownOver) <?0~1o\Ur  
{ <e%F^#y_
 
breakWhile = false; J!ntXF  
break; f&4,?E;6%  
} zNSu  
} ];+#i"l  
if(breakWhile) i{^Z1;Yl  
break; -xg2q V\c  
>%Ee#m  
m6
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//count++; ]v G{kAnH  
//if(count>4) W/=|/-\]/  
// siteStop(); f-2$ L  
} E^hHH?w+  
k#}g,0@  
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System.err.println("文件下载结束！"); !5}l&7:(MN  
} ?@6/Alk  
catch(Exception e){e.printStackTrace ();} |DF9cd^  
} iv(5&'[p  
utlpY1#q/  
r
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3  
//获得文件长度 R)Mt(gFZT_  
public long getFileSize() Xl |1YX1&m  
{ ~Z$bf>[(R7  
int nFileLength = -1; rSP_:}  
try{ iP3Z  
URL url = new URL(siteInfoBean.getSSiteURL()); 02AI%OOH  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection ();  6qo^2  
httpConnection.setRequestProperty("User-Agent","NetFox"); >cL{Ya}Rz  
uk`8X`'  
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int responseCode=httpConnection.getResponseCode(); iF+RnWX\  
if(responseCode>=400) p3^jGj@  
{ "()sb?&  
processErrorCode(responseCode); }i!pL(8;  
return -2; //-2 represent access is error nL]^$J$  
} P5QQpY{<I  
 1;eX&  
Cup@TET35  
String sHeader; IO.<q,pP!_  
o**yZ2  
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for(int i=1;;i++) 4YU/uQm  
{ _DPOyR2  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ());  PWgDFL?  
//Utility.log(in.readLine()); smAC,-6]~  
sHeader=httpConnection.getHeaderFieldKey(i); bzmr"/#D3  
if(sHeader!=null) _'x
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{ ^b?2N/m@  
if(sHeader.equals("Content-Length")) 24\gbv<  
{ PHM:W%g:  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); "L&k)J  
break; g+z
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} u3tZ[Y2 c  
} |I[7,`C~  
else '3l$al:H^  
break; 3mt%!}S  
} 6\dX
 
} )E7 FA|  
catch(IOException e){e.printStackTrace ();} T9y;OG  
catch(Exception e){e.printStackTrace ();} zjX7C~h^Q  
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~KIDv;HSb[  
Utility.log(nFileLength); jkrx]`A{~  
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return nFileLength; Xwu.AVsr  
} D>T],3U(H  
|@VF.)_  
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//保存下载信息（文件指针位置） }3/~x  
private void write_nPos() J>S3sP  
{ %.x@gi q  
try{ h!]"R<QQdu  
output = new DataOutputStream(new FileOutputStream(tmpFile)); X.|Ygx  
output.writeInt(nStartPos.length); v1[_}N9f>H  
for(int i=0;i<nStartPos.length;i++) 3-wD^4)O,  
{ {0jI
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// output.writeLong(nPos); d}0qJoH4  
output.writeLong(fileSplitterFetch.nStartPos); &y_? rH  
output.writeLong(fileSplitterFetch.nEndPos); W5DbFSgB  
} CSn<]%GL  
output.close(); .5tg4%l  
} ddpl Pzm#  
catch(IOException e){e.printStackTrace ();} FbSa~uN  
catch(Exception e){e.printStackTrace ();} 7$T8&Mh  
} &&RA4  
^3I'y UsY  
/r$&]C:Fi  
//读取保存的下载信息（文件指针位置） -]"T^wib  
private void read_nPos() 2g`[u|  
{ E)'8U
 
try{ }B!cv{{  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); qJs[i>P[W  
int nCount = input.readInt(); p%RUHN3G[  
nStartPos = new long[nCount]; oFg'wAO.  
nEndPos = new long[nCount]; ,r+"7$  
for(int i=0;i<nStartPos.length;i++) Etnb3<^[t  
{ s^C;>  
nStartPos = input.readLong(); c]m! G'L_/  
nEndPos = input.readLong(); F$6?t.@J  
} .;Y x*]  
input.close(); ]O{_O&w  
} J 3?Dj  
catch(IOException e){e.printStackTrace ();} hH4o;0rqJ  
catch(Exception e){e.printStackTrace ();} J1 tDO?  
} 6mG3fMih.  
:k"rhI  
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private void processErrorCode(int nErrorCode) 03E3cp"  
{ C!UEXj`l9  
System.err.println("Error Code : " + nErrorCode); _-a|VTM  
} QPg2Y<2  
u(vw|nj`  
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//停止文件下载 ?n*fy  
public void siteStop() (:}<xxl  
{ zHFTCL>"  
bStop = true; 5RhF+p4  
for(int i=0;i<nStartPos.length;i++) X ]s"5ju|t  
fileSplitterFetch.splitterStop(); P>htQ  
V/H@vKN2  
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} I6w/0,azC  
} Qb@eK$wo}  
//负责部分文件的抓取
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**FileSplitterFetch.java BjD&>gO)  
*/ jU$Y>S>l  
package NetFox; m "]!I~jd  
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import java.io.*; 6&],WGz  
import java.net.*; 46ChMTt  
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public class FileSplitterFetch extends Thread { syFI$rf _  
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String sURL; //File URL 2v^lD('  
long nStartPos; //File Snippet Start Position YC)hX'A\  
long nEndPos; //File Snippet End Position 1o#vhk/"+  
int nThreadID; //Thread's ID i<:p.ug-O  
boolean bDownOver = false; //Downing is over u9}!Gq  
boolean bStop = false; //Stop identical AF[>fMI  
FileAccessI fileAccessI = null; //File Access interface  1~EO+  
:0dfB&7  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 0WS|~?OR@  
{ *f*f&l%  
this.sURL = sURL; !rHx}n{rw  
this.nStartPos = nStart; @U7Dunu*f  
this.nEndPos = nEnd; +E#PJ_H=F8  
nThreadID = id; z[biK|YL  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 $B ?? Ip?P  
} Y UZKle  
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public void run() [D9
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{ "i''Ui\H  
while(nStartPos < nEndPos && !bStop) 2lJZw@  
{ y*|L:!   
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try{ J(hA^;8:  
URL url = new URL(sURL); dqwWfn1lt  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); iE+6UK  
httpConnection.setRequestProperty("User-Agent","NetFox"); u2,H ]-  
String sProperty = "bytes="+nStartPos+"-"; E@]sq A  
httpConnection.setRequestProperty("RANGE",sProperty); ]W|RtdF3.N  
Utility.log(sProperty); K Dz]wNf  
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InputStream input = httpConnection.getInputStream(); i"fCpkAP  
//logResponseHead(httpConnection); ;r=?BbND?  
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byte[] b = new byte[1024]; a'^0.1  
int nRead; |P~q/Wff  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 777rE[\@b  
{ EFv4=OWB  
nStartPos += fileAccessI.write(b,0,nRead); :'ihE\j  
//if(nThreadID == 1) um{e&5jk  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); f:FpyCo=9  
} :4]J
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}_vM&.GFlL  
Utility.log("Thread " + nThreadID + " is over!"); F b2p(.  
bDownOver = true; )?9\$^I  
//nPos = fileAccessI.write (b,0,nRead); U>1b9G"_  
} mR!rn^<l  
catch(Exception e){e.printStackTrace ();} #\0TxG5'QA  
} [{/$9k-aF?  
} k)Zn>  
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A
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//打印回应的头信息 ~Q_F~0y  
public void logResponseHead(HttpURLConnection con) lnjL7x  
{ 6w@,I;  
for(int i=1;;i++) CJ:uYXJJ:z  
{ AO^]>/7ed  
String header=con.getHeaderFieldKey(i); 0+p 5/5  
if(header!=null) ` )]lUvR  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); :`;(p{  
Utility.log(header+" : "+con.getHeaderField(header)); :5G$d%O=2  
else %db3f z  
break; +{'lZa  
} s?5d  
} >Rr!rtc'x  
.dt#2a_5q  
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public void splitterStop() i5Eeg`NMl  
{ F],TG&>5  
bStop = true; 2S'AIuIew
 
} ~U/8 @gR  
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?${V{=)*X'  
} TdNsyr}JG  
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e{:86C!d)  
/* '}@e5^oL  
**FileAccess.java  &Q<EfB  
*//文件访问(定位，写) 8b{U tT  
package NetFox; f8R+7Ykx  
import java.io.*; /%-o.hT  
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public class FileAccessI implements Serializable{  .fbYB,0w  
l'W3=,G[?  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 /(y4
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RandomAccessFile oSavedFile; _d/GdeLs  
long nPos; rtcJ=`)0`  
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public FileAccessI() throws IOException Vn@A]Jx^  
{ D\n>*x  
this("",0); ,zc"udpKF  
} bJANZn|H  
H&w(]PDh  
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public FileAccessI(String sName,long nPos) throws IOException $#TID=  
{ o.p+j  
oSavedFile = new RandomAccessFile(sName,"rw"); O.]_Ry\OXA  
this.nPos = nPos; md.*  
oSavedFile.seek(nPos); }R4(B2vup  
} m2jwqx{G  
~WzMK  
)J{.Cx<E  
public synchronized int write(byte[] b,int nStart,int nLen) GU2]/\W*a  
{ aeLBaS  
int n = -1; 1hF2eNh  
try{ 2Y9y5[K,F)  
oSavedFile.write(b,nStart,nLen); "tqS|ok.  
n = nLen; unx;m$-c  
} 3S;>ki4(0  
catch(IOException e) muW`pm  
{ Bi'I18<  
e.printStackTrace (); J11dqj  
} Pw0{.W~r  
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@\#'oIc|  
return n; ?psOj%  
} ]!n*V
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} &z7N\n  

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9OE_?R0c!  
/* se4w~\/  
**SiteInfoBean.java F! |TW6)gv  
*/ I|Vk.,  
package NetFox; N )b|  
:_W0Af09  
gvow\9{|C  
public class SiteInfoBean { 8:;u v7p  
k#{lt-a/  
9\\@I =;  
private String sSiteURL; //Site's URL ~nLkn#Z  
private String sFilePath; //Saved File's Path f'7d4  
private String sFileName; //Saved File's Name .Y=Z!Q  
private int nSplitter; //Count of Splited Downloading File K8e4ax  
pZni,<Q  
S
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public SiteInfoBean() g?k#wj1uH  
{//nSplitter的缺省值为5 yt]Oj*nn0K  
//default value of nSplitter is 5 Fm-q=3  
this("","","",5); &!3VqHQ`  
} `
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!  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) d;@E~~o?B]  
{ ^sr:N5~z`  
sSiteURL= sURL; C*Y :w  
sFilePath = sPath; _47j9m]f  
sFileName = sName; \i&vO
H'  
this.nSplitter = nSpiltter; 8u7K$Q
 
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V1UUAvN7s  
} >"PqQO  
'@3a,pl  
?=pZmvQg  
public String getSSiteURL() 1{;[q3a  
{ =Qjw.6@  
return sSiteURL; \4]zNV ~x  
} &r5&6p  
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hIE%-
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public void setSSiteURL(String value) \N-|
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{ ZC9.R$}Kl  
sSiteURL = value; UH1S_:6  
} &deZ  
U{U:8==  
4EaSg#  
public String getSFilePath() .O@q5G  
{ {7
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return sFilePath; o|p;6  
} KV)Hywl`  
mTI\,x%<OC  
$)kBz*C[  
public void setSFilePath(String value) #NVF\  
{ =:
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sFilePath = value; VDb,$i.Z0  
} 8VAYIxRv  
T9U2j-lA?  
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public String getSFileName() D:RBq\8  
{ /z.7:<gZ(  
return sFileName; {8*d;[X50  
} [EW$7 se~  
)$Dcrrj  
%Mb( c+7  
public void setSFileName(String value) .5#tB*H  
{ |R &3/bEr  
sFileName = value; $jUS[.S_|I  
} b0zx
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U||w6:W5  
#sm_.?P  
public int getNSplitter() 6|"!sW`%N  
{ ="'P=Xh!8  
return nSplitter; J6^Ct  
} JPoK\-9NT  
9 z8<[>  
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public void setNSplitter(int nCount) iz%A0Z+`bg  
{ Vm,f3~  
nSplitter = nCount; "Wn?8vR  
} P!4{#'_
}  
} x(/@Pt
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6yl;o_6:  
/* KWn
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**Utility.java &xiDG=I#  
*/ 6Qzu
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package NetFox; LGo@F;!n  
+~i+k~{`H  
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public class Utility { ~y-vKCp|  
y T1Qep  
,GXfy9x7U  
public Utility()
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{ ]ZryY EB  
&Lt$a_y>  
u6S0t?Udap  
} 4htSwK+  
tMPXvE  
//线程睡眠 L/iVs`qF  
public static void sleep(int nSecond) _{Q?VQvZ  
{ mJDKxgGK  
try{ :C:N]6_{SZ  
Thread.sleep(nSecond); >$S,>d_k`  
} yzM+28}L<I  
catch(Exception e) eE.5zXU3R  
{ a+>W  
e.printStackTrace (); ?:''VM.  
} mP$G9R  
} *_).UAP.  
gHh.|PysW  
//日志 @;n$caw  
public static void log(String sMsg) VgZaDd;  
{ EDidg"0p  
System.err.println(sMsg); }MavI'  
} w[$nO#  
,M/#Q6P0}  
va/4q+1GfH  
public static void log(int sMsg) MkNURy>
n&  
{ `2(R}zUHN  
System.err.println(sMsg); D"] [&m  
} `2mbF^-4  
} ZAM+4#@  
$Z%aGc*  
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/* gM5p1?E  
**TestMethod.java @<TfA>*VJ  
*/ X-N$+[#  
package NetFox; IL6f~!  
};|PFWs  
5 *pN<S  
public class TestMethod { ks#Z~6+3  
/jn3'q_,  
&pY G  
public TestMethod()
u g:G9vjQ  
{ ///xx/weblogic60b2_win.exe i(f;'fb*  
try{ 6[h$r/GXh"  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); f~"V  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); FvNSu"O~K1  
SiteFileFetch fileFetch = new SiteFileFetch(bean); v.LUK  
fileFetch.start(); wAOVH].  
} V&+$Vq  
catch(Exception e){e.printStackTrace ();} eeJt4DV8v  
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Nb!6YY=Ez-  
} ;7n*PBUJJ  
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public static void main(String[] args) PUZXmnB  
{ F%+rOT<5  
new TestMethod(); 6u, 0y$3  
} ~B*\k^
t`  
} aq,)6P`  
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