http断点续传简单实现（java)

/* LUB${0BrA  
**SiteFileFetch.java wLc4Dm*V  
*/ HY)-/  
package NetFox; *(C(tPhC  
import java.io.*; HK`I\,K  
import java.net.*; ZKHG!`X0  
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public class SiteFileFetch extends Thread { fU=B4V4@  
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SiteInfoBean siteInfoBean = null; //文件信息Bean iQDx{m3]  
long[] nStartPos; //开始位置 {|I;YDA  
long[] nEndPos; //结束位置 Z}$TKO*u  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 )W/;=K  
long nFileLength; //文件长度 cufH?Xg<  
boolean bFirst = true; //是否第一次取文件 UMAgA!s  
boolean bStop = false; //停止标志 dXF^(y]l  
File tmpFile; //文件下载的临时信息 p w8 s8?  
DataOutputStream output; //输出到文件的输出流 ,) J~,^f6  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 93Co}@Y;Y+  
public SiteFileFetch(SiteInfoBean bean) throws IOException 3EJt%}V$k  
{ (=7Cs  
siteInfoBean = bean; 9$2/MT't  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 0a80 LAK  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); R(q~ -3~  
if(tmpFile.exists ()) &=VDASEu  
{ +
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bFirst = false; %CK^Si%+  
read_nPos(); ^fZ&QK  
} s"t$0cH9  
else >=[(^l  
{ 'Lu__NfN  
nStartPos = new long[bean.getNSplitter()]; '7XIhN9  
nEndPos = new long[bean.getNSplitter()]; H$y-8-&)  
} 0`^&9nR  
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} (1#J%  
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public void run() '&\kxNglJ  
{ h*-Pr8  
//获得文件长度 \[y`'OD~  
//分割文件 PYGRsrcFd#  
//实例FileSplitterFetch ~]QHk?[wc  
//启动FileSplitterFetch线程 /5u<78GW1  
//等待子线程返回 oH_;4QU4y  
try{ =3L;Z[^9  
if(bFirst) =weSyZ1~  
{ -3Hy*1A.  
nFileLength = getFileSize(); Mnscb  
if(nFileLength == -1) gP;&e:/3  
{ Q)IKOt;N]  
System.err.println("File Length is not known!"); xL\0B,]  
} thI F&  
else if(nFileLength == -2) >r!|sC  
{ RJd(~1  
System.err.println("File is not access!"); Ymg|4
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} )c)vTZy  
else [n:<8ho  
{ }hhGu\  
for(int i=0;i<nStartPos.length;i++) !O<)\)|g  
{ "g1)f"pL  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); T\D}kQM  
} ,^2>k3=  
for(int i=0;i<nEndPos.length-1;i++) `hQ5VJo  
{ Fvbh\m ~  
nEndPos = nStartPos[i+1]; tNbN7yI  
} !6*"(  
nEndPos[nEndPos.length-1] = nFileLength; R^Y <RI  
} |&zz,
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} s+<Yg
$)  
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//启动子线程 g\&g N  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; >s<^M|S07  
for(int i=0;i<nStartPos.length;i++) ivN&HAxI@  
{ f=WDR m]  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 0"f\@8r(  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), G;l_|8<t#\  
nStartPos,nEndPos,i); .oeX"6K  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); oU.R2\Q  
fileSplitterFetch.start(); zd >t-?g  
} <nT +$   
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), R8a3 1&  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); .nx2";oi  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ?gt l)q  
nEndPos = " + nFileLength); %5"9</a&G  
// fileSplitterFetch[nPos.length-1].start(); G$F<$  
Wa{`VS  
@eKec1<  
//等待子线程结束 ddJe=PUb  
//int count = 0; ! t?iXZ  
//是否结束while循环 :%,:"  
boolean breakWhile = false; #ML%ij 1  
]H+8rY%+  
,)Znb=  
while(!bStop) 4\8+9b\9"  
{ 1cpiHZa  
write_nPos(); !ug8SAOaz/  
Utility.sleep(500); 5>D>% iaHv  
breakWhile = true; Q7jb'y$ozO  
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for(int i=0;i<nStartPos.length;i++) KUlp"{a`,K  
{ 3sy (vC  
if(!fileSplitterFetch.bDownOver) ;;6uw\6 O  
{ V{/?FO?E  
breakWhile = false; a%/9v"}  
break; s@K4u^$A  
} 8 Hg+H=?  
} 2fn&#kw/  
if(breakWhile) 
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break; \J
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//count++; ^:^9l1]  
//if(count>4) =5~jx  
// siteStop(); FQ<Ju.  
} [+n*~
  
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System.err.println("文件下载结束！"); mwHB(7YS,  
} ^/I 7|u]  
catch(Exception e){e.printStackTrace ();} < $lCkSx<Q  
} 7&jTtKLj  
K*LlW@  
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//获得文件长度 ,Z&xNBX  
public long getFileSize() -#u=\
8  
{ %)zodf  
int nFileLength = -1; r*2+xDoEi  
try{ )rxX+k+b/  
URL url = new URL(siteInfoBean.getSSiteURL()); I9_RlAd  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); D#cyOrzy  
httpConnection.setRequestProperty("User-Agent","NetFox"); RzE_K'M  
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int responseCode=httpConnection.getResponseCode(); SJb&m-  
if(responseCode>=400) ZxGJzakB5$  
{ }YGV\Nu  
processErrorCode(responseCode); ayR-\mZ  
return -2; //-2 represent access is error &^ 1$^=  
} ,8U&?8l  
snE8 K}4  
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String sHeader; x<tb  
i[7\[  
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for(int i=1;;i++) =Y{(%sn  
{ <\rT%f}3^  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); >E;uU[v)I  
//Utility.log(in.readLine()); \A 2r]  
sHeader=httpConnection.getHeaderFieldKey(i); qeVfE_<  
if(sHeader!=null) @ym v< Mo  
{ <wN}X#M  
if(sHeader.equals("Content-Length")) Y,<{vLEC  
{ ^oBtfN>4  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); tqE6>"jD  
break; JVvs-bK5
 
} Ns
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} +~m46eI  
else XixL 
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break; ?uzRhC_)!  
} 7zXvnxYE  
} )WNzWUfn=z  
catch(IOException e){e.printStackTrace ();} 4Tb #fH%  
catch(Exception e){e.printStackTrace ();}
HSjlD{R  
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Utility.log(nFileLength); Q{sH3Y#l  
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return nFileLength; 9UdM`v)(  
} HJ=
:8:  
!![DJ  
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//保存下载信息（文件指针位置） w1EXh  
private void write_nPos() -;s|  
{ xI#9  
try{ Qp)v?k ]  
output = new DataOutputStream(new FileOutputStream(tmpFile)); oR)Jznmi}  
output.writeInt(nStartPos.length); @Q)OGjaq  
for(int i=0;i<nStartPos.length;i++) @'#,D!U  
{ \FQRNj?'_  
// output.writeLong(nPos); PS)4 I&;U  
output.writeLong(fileSplitterFetch.nStartPos); 2V- 16Q'%  
output.writeLong(fileSplitterFetch.nEndPos); Z3"%`*Tmq-  
} (5$!MUS~9  
output.close(); EU2$f  
} |7'df&CA  
catch(IOException e){e.printStackTrace ();} *v;2PP[^  
catch(Exception e){e.printStackTrace ();} CM/H9Kz.  
} $O&b``  
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//读取保存的下载信息（文件指针位置） b z`+k,*  
private void read_nPos() B nFwlw  
{ dP9qSwTa  
try{ Q3kdlxXR  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); -]0OKE&  
int nCount = input.readInt(); .5^cb%B*  
nStartPos = new long[nCount]; hQ,ch[j'  
nEndPos = new long[nCount]; pNG:0  
for(int i=0;i<nStartPos.length;i++) y;35WtDVb  
{ j+i\bks  
nStartPos = input.readLong(); G,&<<2{(f;  
nEndPos = input.readLong(); Ep9nsX*   
} ;km`P|
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input.close(); zJq~!#pZ  
} Rvqq.I8aC  
catch(IOException e){e.printStackTrace ();} RD!&LFz/}  
catch(Exception e){e.printStackTrace ();} *RI]?j%B  
} l.67++_  
)tC5Hijq,  
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private void processErrorCode(int nErrorCode) LdYB7T,  
{ v> LIvi|]  
System.err.println("Error Code : " + nErrorCode); "3X2VFwo
J  
} VACQ+  
R3 -n>
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//停止文件下载 Vh'P&W?[  
public void siteStop() F%@A6'c  
{ E-T)*`e  
bStop = true; }n]
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for(int i=0;i<nStartPos.length;i++) ;,hwZZ
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fileSplitterFetch.splitterStop(); @:oXN]+ _  
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} Yxr>"KH6a  
} :y'Ah#  
//负责部分文件的抓取 ,82S=N5V!  
**FileSplitterFetch.java A!od9W6  
*/ Y>dF5&(kb  
package NetFox; /K+r? ]kf  
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import java.io.*; &fDIQISC  
import java.net.*; +5w))9@  
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public class FileSplitterFetch extends Thread { Gj1&tjK  
0\X\izQ5  
!S$:*5=&  
String sURL; //File URL 8v:T.o;<  
long nStartPos; //File Snippet Start Position 3U<cWl@  
long nEndPos; //File Snippet End Position e),q0%5  
int nThreadID; //Thread's ID dcDyK!zz"  
boolean bDownOver = false; //Downing is over !8TlD-ZT/  
boolean bStop = false; //Stop identical _zR+i]9   
FileAccessI fileAccessI = null; //File Access interface +Z
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException T-'OwCB1q  
{ 8V~k5#&Ow  
this.sURL = sURL; P@,XEQRd`  
this.nStartPos = nStart; ,kyJAju>  
this.nEndPos = nEnd; $jjfC  
nThreadID = id; [8Y:65  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 _'#n6^Us<  
} 
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tP:lP#9  
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public void run() 9e<.lb^tP  
{ `fA@hK   
while(nStartPos < nEndPos && !bStop) ^7w+l @  
{ r)Ma3FL0;  
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try{ >Rl"  
URL url = new URL(sURL); 8+~ >E  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); wy<\Tg^J  
httpConnection.setRequestProperty("User-Agent","NetFox"); uu-PJTNZ  
String sProperty = "bytes="+nStartPos+"-"; -"R2  
httpConnection.setRequestProperty("RANGE",sProperty); #Vnkvvv  
Utility.log(sProperty); kDEXN  
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InputStream input = httpConnection.getInputStream(); Y[ j6u\y  
//logResponseHead(httpConnection); f&=AA@jLv  
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byte[] b = new byte[1024]; qFicBpB  
int nRead; G'nmllB`]  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Q3XpHnufu+  
{ 1rNzJ;'  
nStartPos += fileAccessI.write(b,0,nRead); `}D,5^9]  
//if(nThreadID == 1) kI,yU}<Fq  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Q{O+  
} Giid~e33  
Z]A{ d[  
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Utility.log("Thread " + nThreadID + " is over!"); M-$%Rzl_  
bDownOver = true; lXx=But  
//nPos = fileAccessI.write (b,0,nRead); L 8c0lx}Nn  
} sG(~^hJ_  
catch(Exception e){e.printStackTrace ();} ]vz%iv_  
} M=8.Bp|Ye  
} ZFiee|,q  
](Xb_xMf  
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//打印回应的头信息 fnpYT:%fG  
public void logResponseHead(HttpURLConnection con) Y@NNrGDkT*  
{ \e:7)R2<!x  
for(int i=1;;i++) wVvF^VHV^  
{ %h hf
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String header=con.getHeaderFieldKey(i); O;+ m
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if(header!=null) NyaQI<5D  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); n"h`5p5'  
Utility.log(header+" : "+con.getHeaderField(header)); 6gkV*|U,e  
else `:ArT}F  
break; $r^GE  
} On8v//=&  
} "x#-sZ=  
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public void splitterStop() raW>xOivR  
{ *zaQx+L  
bStop = true; p99]  
} <3oWEm  
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} {IjF+@I  
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/* !-g{[19\  
**FileAccess.java ]dF ,:8  
*//文件访问(定位，写) 9G9t" {  
package NetFox; UgRhWV~f0  
import java.io.*;  |{&{  
d.[8c=$  
#?RU;1)Cw  
public class FileAccessI implements Serializable{ 2\R'@L*  
_1!7V3|^  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 xn?a. 3b'  
RandomAccessFile oSavedFile; m1j*mtu  
long nPos; QpF;:YX^3  
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public FileAccessI() throws IOException b k~(^!R  
{ N(O9&L*4fm  
this("",0); %9 SJ E  
} i9rN9Mq?O  
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;B|{  
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public FileAccessI(String sName,long nPos) throws IOException @Rg/~\K  
{  nI[os  
oSavedFile = new RandomAccessFile(sName,"rw"); >R|/M`<ph  
this.nPos = nPos; n"$jG:AQJ  
oSavedFile.seek(nPos); R%Hi+#/dr-  
} +[
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public synchronized int write(byte[] b,int nStart,int nLen) LmRy1T,act  
{ Dxtp2wu%t  
int n = -1; S};#+ufgTt  
try{ SbcS]H5Sk  
oSavedFile.write(b,nStart,nLen); .[YuRLGz  
n = nLen; ]GUvV&6@(  
} 
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catch(IOException e) f<GhkDPm>?  
{ 1}"++Z73P  
e.printStackTrace (); a a<8,;  
} 0`Kj25  
] ;KJ6  
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return n; m.hkbet/R  
} V#v`(j%  
b}\N;D.{  
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} 6=kEyJT'  
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/* SfA\}@3  
**SiteInfoBean.java SQ@y;|(  
*/ x;w6na  
package NetFox; tE.FrZS  
G`+T+  
A4Rug\p]  
public class SiteInfoBean { #HYr0Tw6`  
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private String sSiteURL; //Site's URL PYQ;``~x  
private String sFilePath; //Saved File's Path W=lyIb{?^0  
private String sFileName; //Saved File's Name \1d(9jR  
private int nSplitter; //Count of Splited Downloading File Ltv]pH}YN  
=pr`'  
"7U4'Y:E  
public SiteInfoBean() 1f%1*L0>@  
{//nSplitter的缺省值为5 T _r:4JS  
//default value of nSplitter is 5 oVnvO iAc  
this("","","",5); 60P<4
 
} "33Fv9C#bK  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 'QJ:`)z  
{ V4hiGO[  
sSiteURL= sURL;  Fiv3 {.  
sFilePath = sPath; ,ZaRy$?  
sFileName = sName; p5Z"|\  
this.nSplitter = nSpiltter; <5d~P/,  
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} svsqg{9z  
-#7'r<I9@  
,NOsFO-`<  
public String getSSiteURL() ~Io7]  
{ j_/>A=OD  
return sSiteURL; Yf:IKY  
} 5c9^-|-T  
^"2i   
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public void setSSiteURL(String value) ?:pP8/y  
{ ~Uj=^leYO  
sSiteURL = value; *RDn0d[  
} 2SD`OABf#  
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public String getSFilePath() u$h 4lIl  
{ QaS1
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return sFilePath; 8k2?
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} F7 5#*  
67VL@ ]  
# Nk;4
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public void setSFilePath(String value) *7:>EP  
{ \jh'9\  
sFilePath = value; >/g#lS 5  
} +"x,x  
wHzEMwY_  
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public String getSFileName() f6EZ( v  
{ \"qY"V  
return sFileName; Vl5`U'^qx  
} ) dn(G@5  
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2-&k^Gl!:  
public void setSFileName(String value) <x@}01~  
{ YO#M/%^j  
sFileName = value; =w;F<M|Y  
} pyH:#5  
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public int getNSplitter() 9l|@v=gw.  
{ 6TYY UM"&  
return nSplitter; xRJ\E }/7  
} M.Y~1c4f  
8R2QZXJb-  
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public void setNSplitter(int nCount) cU RkP`  
{  0bz'&  
nSplitter = nCount; ?@BTGUK"C  
} .Fs7z7?Y  
} M:XSQ["6>V  
U [*FCD!~  
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/* c(J!~7  
**Utility.java 1cx
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*/ lAi6sPG)0  
package NetFox; c$ao:nP)D  
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public class Utility { FFV `P  
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public Utility() `lQ3C{}  
{ $Oq^jUJ  
]*vdSr-J  
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} tU4s'J  
R,gR;Aarw  
//线程睡眠 \Npxv  
public static void sleep(int nSecond) mIurA?&7!  
{ 3cFf#a#  
try{ AZ0;3<FfLp  
Thread.sleep(nSecond); H+1-]'g`  
} Y?S!8-z  
catch(Exception e) ahuGq'  
{ ?/BqD;{?I  
e.printStackTrace (); wr5AG<%(  
} +s(HO
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} &]8P1{  
9zZr^{lUl  
//日志 ,.rs(5.z8/  
public static void log(String sMsg) !HrKXy0{  
{ l9}3XI.=  
System.err.println(sMsg); q'|rgT  
} pczug-nB  
lH#u  
|L-]fjBbF  
public static void log(int sMsg) K17j$o^6KK  
{ RLw;(*(g  
System.err.println(sMsg); h^?\xm|  
} { WIJC',Y  
} g>Y|9Y  
UADFnwR[R  
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/* Rd2qe /  
**TestMethod.java #,,d>e  
*/ [ad@*KFxy3  
package NetFox; aAJU`=u
q  
I`p+Qt  
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public class TestMethod { Inn@2$m~  
txW{7+,  
Q?e*4ba  
public TestMethod() QOjqQfmM;  
{ ///xx/weblogic60b2_win.exe qLw{?sH}J/  
try{ #i@;J]x(  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); gGr^@=;YC  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Px$/ _`H  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 0TCBQ~"  
fileFetch.start(); {aY%gk?y#>  
} GKOD/,  
catch(Exception e){e.printStackTrace ();} ugo.@   
b6}H$Sx~  
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} h?rp|uPQ  
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public static void main(String[] args) =x!2Ak/)  
{ .uuO>:  
new TestMethod(); |kw)KEi}H  
} UF?H>Y&  
} iTFdN}
U  
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