http断点续传简单实现（java)

/* Blzvn19'h  
**SiteFileFetch.java G$i)ELs  
*/ 950N\Y@u  
package NetFox; %|(c?`2|  
import java.io.*; WsV"`ij#  
import java.net.*; p 4>ThpX  
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public class SiteFileFetch extends Thread { {s0%XG1$  
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SiteInfoBean siteInfoBean = null; //文件信息Bean H\ejW@<;h  
long[] nStartPos; //开始位置 TSP%5v;Dh  
long[] nEndPos; //结束位置 0Xh_.PF  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 edp I?  
long nFileLength; //文件长度 VjM3M<!g>M  
boolean bFirst = true; //是否第一次取文件 h
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boolean bStop = false; //停止标志 h.>SVQzU  
File tmpFile; //文件下载的临时信息 ,\\ba_*z  
DataOutputStream output; //输出到文件的输出流 ~Xxmj!nOf  
#%p44%W  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） <(lA C
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public SiteFileFetch(SiteInfoBean bean) throws IOException tf~B,?  
{ Kk8}m;  
siteInfoBean = bean; ~U&NY7.@  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); AYA{_^#+3  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); C.92FiC  
if(tmpFile.exists ()) !lgL=Ys(  
{ H>EM3cFU  
bFirst = false; TBBnsj6e  
read_nPos(); {'O><4  
} SO0\d0?u  
else $
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{ !RmVb}m  
nStartPos = new long[bean.getNSplitter()]; j HHWq>=d  
nEndPos = new long[bean.getNSplitter()]; R#d~a;j  
} Zok{ndO@|f  
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} :*''ci  
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public void run() Q4"\k. ?  
{ n(F!t,S1i  
//获得文件长度 q`<:CfCt  
//分割文件 P9cx&Hk9  
//实例FileSplitterFetch 2^WJ1: A  
//启动FileSplitterFetch线程 l/X_CM8y~  
//等待子线程返回 l'+3 6  
try{ S:_Ms{S  
if(bFirst) C$y6^/7)  
{ YvU%OO-+,  
nFileLength = getFileSize(); 15g!Q *v  
if(nFileLength == -1) ,&t+D-s<f  
{ te+}j7SU  
System.err.println("File Length is not known!"); V,&%[H [  
} l$;"yVdks  
else if(nFileLength == -2) 9*)&hhBs,  
{ ff#7}9_mh  
System.err.println("File is not access!");
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} X8|H5Y:  
else RPz[3y  
{ ~`OX}h/Z  
for(int i=0;i<nStartPos.length;i++)  ?.?)5 &4  
{ e%\^V\L  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); p&<Ssc  
} 
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for(int i=0;i<nEndPos.length-1;i++) buGBqx[  
{ Ia&*JYM[  
nEndPos = nStartPos[i+1]; OpUfK4U)  
} bWswF<y-  
nEndPos[nEndPos.length-1] = nFileLength; 7AqgX0)  
} Tru{8]uMH  
} 7Q .Su  
\
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*d1BpR%  
//启动子线程 kt6x"'"1  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; _\WR3Q!V  
for(int i=0;i<nStartPos.length;i++) Dh I{&$O/  
{ ) O0Cz n  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 8MJJ w;  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), AjVC{\Ik  
nStartPos,nEndPos,i); m!V,W*RNr  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); hLO)-ueb  
fileSplitterFetch.start(); yE$PLM  
} %6m/ve  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), uwNJM  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); |#TU"$;  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", @?,x3\N-  
nEndPos = " + nFileLength); )(}[S:`  
// fileSplitterFetch[nPos.length-1].start(); -H-U8/WC  
uC'-: t#  
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//等待子线程结束 D#g-mqar:  
//int count = 0; E'QAsU8pP  
//是否结束while循环 ;vH2r~  
boolean breakWhile = false; 0]DOiA  
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while(!bStop) Q"QRF5Ue  
{ E2e"A I.h  
write_nPos(); F]$ Nu  
Utility.sleep(500); mrTf["K  
breakWhile = true; Ni_H1G  
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for(int i=0;i<nStartPos.length;i++) y~9wxK  
{ ~MG6evm &  
if(!fileSplitterFetch.bDownOver) 42Z:J 0  
{ O=0p}{3l  
breakWhile = false; !dqC6a  
break; r&u1-%%9[  
} Za|7gt];l  
} _H
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if(breakWhile) +b|F_  
break; P3oYk_oW  
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L!Jx`zM^  
//count++; pzF_g-B  
//if(count>4) [OC(~b  
// siteStop(); y1V}c,  
} W{,fpm  
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System.err.println("文件下载结束！"); A4j,]hOD  
} 49qa  
catch(Exception e){e.printStackTrace ();} TegdB|y7O  
} ]cRvdUGv  
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+t7HlAXB#  
//获得文件长度 3D|Lb]=  
public long getFileSize() Gs
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{ [L%Ltmx  
int nFileLength = -1; ']}-;m\  
try{ Tuvs}  
URL url = new URL(siteInfoBean.getSSiteURL()); a"(Ws]K  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); WIWo4[(  
httpConnection.setRequestProperty("User-Agent","NetFox"); b_+o1Zy`  
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int responseCode=httpConnection.getResponseCode(); [@K'}\U^+  
if(responseCode>=400)
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{ ?$pNduE  
processErrorCode(responseCode); rz|T2K  
return -2; //-2 represent access is error &8VH m?h  
} !)M}(I}  
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String sHeader; Q& [!+s:2J  
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for(int i=1;;i++) c)EYXo  
{ z%}"=  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); o$@/@r  
//Utility.log(in.readLine()); `I7s|9-=  
sHeader=httpConnection.getHeaderFieldKey(i); XT^=v6^H  
if(sHeader!=null) ]}`t~#Irz  
{ `xM*cJTZ  
if(sHeader.equals("Content-Length")) MTYV~S4/  
{ w,1N ;R&  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 9SC1A-nF  
break; ^gVQ6=z%  
} XfcYcN  
} < F5VJ  
else _a&gbSQv  
break; wBt7S!>G  
} rfDGS%!O%  
} |q4=*Xq  
catch(IOException e){e.printStackTrace ();} g$Tsht(rHD  
catch(Exception e){e.printStackTrace ();} TOiLv.Dor  
{aE[h[=r  
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Utility.log(nFileLength); b^R:q7ea  
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return nFileLength; p5]W2i.,  
} ;adZ*'6u  
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//保存下载信息（文件指针位置） 3]S*p ErY  
private void write_nPos() :$I"n\  
{ 0\i\G|5  
try{ 6jpzyf=~  
output = new DataOutputStream(new FileOutputStream(tmpFile)); &>-'|(m+2  
output.writeInt(nStartPos.length); u^Cls!C  
for(int i=0;i<nStartPos.length;i++) 8wWp+Hk  
{ f@sC~A. 9\  
// output.writeLong(nPos); mx
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output.writeLong(fileSplitterFetch.nStartPos); '@t,G,FJ  
output.writeLong(fileSplitterFetch.nEndPos); w/NT5  
} \BBs;z[/  
output.close(); kQI'kL8>  
} :V(C+bm *  
catch(IOException e){e.printStackTrace ();} X -1r$.
  
catch(Exception e){e.printStackTrace ();} LR&MhG7  
} 2IJniS=[>  
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//读取保存的下载信息（文件指针位置） Q`i@['?p  
private void read_nPos() $2FU<w$5  
{ U*nB= =  
try{ x)80:A}  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); "1|geO|  
int nCount = input.readInt(); h.-L_!1B7  
nStartPos = new long[nCount]; &._"rhz  
nEndPos = new long[nCount]; `K VSYC  
for(int i=0;i<nStartPos.length;i++) 39^+;Mev  
{ )EMlGM'2q  
nStartPos = input.readLong(); $`OyGeq"T  
nEndPos = input.readLong(); d/GSG%zB
 
} @o[ZJ4>*  
input.close(); m 70r'b]  
} Q'U!  
catch(IOException e){e.printStackTrace ();} gZHgL7@  
catch(Exception e){e.printStackTrace ();} 
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} AXcmN  
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private void processErrorCode(int nErrorCode) Xf ^_y(?  
{ ttr`  
System.err.println("Error Code : " + nErrorCode); &SIf|IX.  
} e!Z}aOeE  
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//停止文件下载 \<I&utn  
public void siteStop() /y1+aTiJ  
{ L%[>z'Zp  
bStop = true; @nqM
#  
for(int i=0;i<nStartPos.length;i++) [<r.M<3  
fileSplitterFetch.splitterStop(); b4:{PD~Mh  
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]U@~vA#''  
} q1HJ_y  
} KrP?*yk  
//负责部分文件的抓取 'Rnzu0<lF  
**FileSplitterFetch.java #^9bBF/  
*/ o5/BE`VD5c  
package NetFox; aF/DFaiYv  
xd `MEOY  
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import java.io.*; o w(9dB&E  
import java.net.*; wMgF*  
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public class FileSplitterFetch extends Thread { ~%lUzabMa  
{$t*XTY6R  
%1 RWF6  
String sURL; //File URL _{):w~zi  
long nStartPos; //File Snippet Start Position |WUM=g7PC  
long nEndPos; //File Snippet End Position ,e|"p[z~T  
int nThreadID; //Thread's ID B0 A`@9  
boolean bDownOver = false; //Downing is over z\FBN=54z  
boolean bStop = false; //Stop identical 4'3;{k$z  
FileAccessI fileAccessI = null; //File Access interface {1=|H$wKg  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException tvno3"  
{ v?8i;[  
this.sURL = sURL; PcbhylKd  
this.nStartPos = nStart; /\Cf*cJ  
this.nEndPos = nEnd; jD<xpD  
nThreadID = id; 6 o  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 5{W A
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} erv94acq  
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public void run() t<c7%i#Od  
{ IkmEctAU  
while(nStartPos < nEndPos && !bStop) k|>yFc  
{ @}PXBU   
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try{ a/s5Oit2'X  
URL url = new URL(sURL); Y8%l)g  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); $XcH
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httpConnection.setRequestProperty("User-Agent","NetFox"); 5'DY)s-K  
String sProperty = "bytes="+nStartPos+"-"; LV1drc  
httpConnection.setRequestProperty("RANGE",sProperty); ;t9!<L  
Utility.log(sProperty); UM0Ws|qx&  
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InputStream input = httpConnection.getInputStream(); A ?tna6W:  
//logResponseHead(httpConnection); *BrGh
 
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byte[] b = new byte[1024]; 2Y9u9;ah  
int nRead; i@D4bd9lR  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) #?\(l%  
{ atd;)o0*0  
nStartPos += fileAccessI.write(b,0,nRead); ,j{tGj_  
//if(nThreadID == 1) EF$ASN
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// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); UsA fZg8  
} E,ilJl\  
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Utility.log("Thread " + nThreadID + " is over!"); ]Hl{(v\HO  
bDownOver = true; f tl$P[T  
//nPos = fileAccessI.write (b,0,nRead); K@:omT  
} IP{$lC  
catch(Exception e){e.printStackTrace ();} >h:'Z*9  
} ^uG^>Om*  
} ]Ue aXwaU  
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}'}n~cA.{  
//打印回应的头信息 %${$P+a`D  
public void logResponseHead(HttpURLConnection con) /Q)I5sL@E  
{ `<~=6H  
for(int i=1;;i++) ~}{_/8'5  
{ vP#*if[V5  
String header=con.getHeaderFieldKey(i); B R  
if(header!=null) 4 7mT  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ZXo;E  
Utility.log(header+" : "+con.getHeaderField(header)); ~s-gnp  
else <-' !I&  
break; s8's(*]  
} )2l @%?9  
} Yj bp:  
{7DXSe4  
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public void splitterStop() IIT[^_g  
{ R|$b\3  
bStop = true; iOZ#}"  
} i?b9zn
  
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}=\?]9`  
} CV=qcD  
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/* WcT= 5G  
**FileAccess.java u23_*W\  
*//文件访问(定位，写) ;!VxmZ:j[  
package NetFox; |.m)UFV  
import java.io.*; S:i#|T."  
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public class FileAccessI implements Serializable{ Id`V`|q  
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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 Sx J0Y8#z  
RandomAccessFile oSavedFile; HnjA78%i  
long nPos; \1<|X].jNY  
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public FileAccessI() throws IOException 5y g`

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{ $v#`2S(7  
this("",0);
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} 7q;`~tbC  
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public FileAccessI(String sName,long nPos) throws IOException (y6}xOa(  
{ :Cx|(+T  
oSavedFile = new RandomAccessFile(sName,"rw"); _[E+D0A  
this.nPos = nPos;
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oSavedFile.seek(nPos); k]$oir  
} P%Vq#5  
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public synchronized int write(byte[] b,int nStart,int nLen) \X\f~CB  
{ | ?vm.zp  
int n = -1; K,! V _  
try{ Z- a
  
oSavedFile.write(b,nStart,nLen); Djc-f  
n = nLen; vK+reXE  
} d8agM/F*/  
catch(IOException e) 6|B9kh}  
{ 1,) yEeHjU  
e.printStackTrace (); 8TAJ#Lm  
} <B0f  
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return n; \5!7zPc  
} NZ i3U  
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} a,S;JF)v  
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8 I_  
/* 4c(Em+4  
**SiteInfoBean.java *@PM,tS;  
*/ {]}94T~/k  
package NetFox; 7mdd}L^h Z  
K
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public class SiteInfoBean { 6*>Lud  
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private String sSiteURL; //Site's URL Ky%lu^  
private String sFilePath; //Saved File's Path D@68_sn  
private String sFileName; //Saved File's Name mrnPZf i  
private int nSplitter; //Count of Splited Downloading File |]@Pq[Hn|  
/QyKXg6)l  
!*"fWahv  
public SiteInfoBean() HBOyiIm Q  
{//nSplitter的缺省值为5 P][jB  
//default value of nSplitter is 5 T{3nIF   
this("","","",5); lcm[l  
} fM"*;LN!N  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) A|+QUPD  
{ /IRXk[  
sSiteURL= sURL; KB](W  
sFilePath = sPath; _,T 4DS6  
sFileName = sName; -GCo`PR?b  
this.nSplitter = nSpiltter; BXYH&2]Q  
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} ,n8\y9{
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public String getSSiteURL() kc^,V|Nbq6  
{ @pYEzizP7  
return sSiteURL; aU_Hl+;  
} LO{Axf%  
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public void setSSiteURL(String value) + tMf&BZ  
{ [MFnS",7c  
sSiteURL = value; s||" } l  
} :NF4[
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,?|$DY+=  
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public String getSFilePath() WrGnLE kiV  
{ MqAi}z%  
return sFilePath; vW=L{8zu  
} .N qXdari  
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public void setSFilePath(String value) I} jgz  
{ 3@gsKtA&H4  
sFilePath = value; Ck Nl;g l  
} }<0N)dpT  
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public String getSFileName() ;Nj9,Va(t  
{ aE`d[dSG  
return sFileName; c[,h|~K/_?  
} 6UeYZ g  
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public void setSFileName(String value) O1
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{ 'f-r 6'_ZX  
sFileName = value; 06S R74  
} ~Ba=nn8Cq  
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public int getNSplitter() x)~i`$  
{ {p84fR1P  
return nSplitter; tR|dnC4U  
} a]T:wUYG'  
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public void setNSplitter(int nCount) I x%>aee  
{ kUf i  
nSplitter = nCount; Mqr_w!8d  
} 3T2]V?   
} @b,Az{EH  
gA!@oiq@  
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/* pd|KIs%jl  
**Utility.java y QW7ng7D0  
*/ "B_3<RSL  
package NetFox; zsg\|=P  
@KQ.tF*  
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public class Utility { Tnp P'  
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public Utility() .5(YL8d  
{ c1yRy|  
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} !bE-&c  
\VNu35* J|  
//线程睡眠 7FG;fJ;&NZ  
public static void sleep(int nSecond) S(zp_  
{ E~%n-A  
try{ h1w({<q*ov  
Thread.sleep(nSecond); l6/VJ~(}'  
} K92j BR  
catch(Exception e) m4mE7Wn.3  
{
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e.printStackTrace (); s?w2^<P  
} 1xB}Ed*k  
} [eX]x  
rAH!%~  
//日志 bhqSqU}6~  
public static void log(String sMsg) yQK{ +w  
{ tVAi0`DV  
System.err.println(sMsg); heVkCM :  
} "v8p<JfB`  
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public static void log(int sMsg) NKu[6J?)  
{ )}ev;37<C  
System.err.println(sMsg); >'*%wf[{  
} 6 c
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} jRJG .hcB5  
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/* Q^(CqQo!<  
**TestMethod.java kxMvOB$  
*/ $w0TEO!  
package NetFox; $DY#04Je\=  
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public class TestMethod { @/z\p7e  
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:os8"  
public TestMethod() *f[5rr4  
{ ///xx/weblogic60b2_win.exe ABWn49c.  
try{ @Zt~b'n  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ;c!> =  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); =;Gq:mHi
 
SiteFileFetch fileFetch = new SiteFileFetch(bean); Vrt$/ d  
fileFetch.start(); F9fLJol  
} 5,"c1[`-  
catch(Exception e){e.printStackTrace ();} 2XP }:e  
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UA>=# $  
} u]yy%@U1  
"q=Cye  
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public static void main(String[] args) Q{[@n  
{ wQhNQ(H~\  
new TestMethod(); `i.BB jx`  
} ,mHME~  
} Y^fw37b  
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