http断点续传简单实现（java)

/* +Mijio  
**SiteFileFetch.java 8O]`3oa>  
*/ T 'c39  
package NetFox; B2j1GJEO  
import java.io.*; -c]AS[(  
import java.net.*; ciODTq?  
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[s[ZOi!;I  
public class SiteFileFetch extends Thread { E>]K#H  

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SiteInfoBean siteInfoBean = null; //文件信息Bean -MS#YcsV  
long[] nStartPos; //开始位置 ]87BP%G  
long[] nEndPos; //结束位置 0)Ephsw  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 !Nx1I  
long nFileLength; //文件长度 SC~k4&xy  
boolean bFirst = true; //是否第一次取文件 r~)fAb?  
boolean bStop = false; //停止标志 T8A(W
 
File tmpFile; //文件下载的临时信息 3:nBl?G<  
DataOutputStream output; //输出到文件的输出流 %\<b{x# G  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） w1"+HJd  
public SiteFileFetch(SiteInfoBean bean) throws IOException A/<u>cCW  
{ 4{F1GW  
siteInfoBean = bean; Kb(11$U  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); edo)W mn  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); gEj#>=s  
if(tmpFile.exists ()) *KvD$(ny  
{ c$ZVvu  
bFirst = false; =^u;uS[IW  
read_nPos(); J;obh.}u"{  
} dW4jkjap  
else [y@*vQw  
{
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nStartPos = new long[bean.getNSplitter()]; iv$YUM+  
nEndPos = new long[bean.getNSplitter()]; i$E [@  
} T3P9  
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} 'M>m$cCMZ  
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public void run() /jGBQ-X  
{ @M"gEeI9  
//获得文件长度 )k,n}  
//分割文件 p@G7}'|eyA  
//实例FileSplitterFetch nU_O|l9  
//启动FileSplitterFetch线程 )6)bI.BY  
//等待子线程返回 pjFO0h_Y  
try{ y,nmPX?]n  
if(bFirst) VQla.Y  
{ V_SH90@)+  
nFileLength = getFileSize(); z/{X
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if(nFileLength == -1) h) Wp  
{ ^-Od*
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System.err.println("File Length is not known!"); qazA,|L!  
} +\Vm t[v  
else if(nFileLength == -2) RHC ZP  
{ 3{3@>8{w  
System.err.println("File is not access!"); gY~r{  
} GjhTF|  
else |[>@Kk4  
{ <PpvVDy3  
for(int i=0;i<nStartPos.length;i++) :ZrJL&  
{ "OjAhKfG  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); *XTd9E^tXq  
} tVn?cS  
for(int i=0;i<nEndPos.length-1;i++) |EE1S{!24m  
{ 6^Wep- $  
nEndPos = nStartPos[i+1]; &|>~7(
 
} i 6G40!G=)  
nEndPos[nEndPos.length-1] = nFileLength; _!',%+  
} yU v YV-7  
} C.j
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//启动子线程 =hKAwk/^  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Z0Z6aZeb  
for(int i=0;i<nStartPos.length;i++) {]^Ixm-,f  
{ ?mg@zq8  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 0\%g@j-aD  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ]P?<2,  
nStartPos,nEndPos,i); |ri)-Bk ,  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 9wWBE<}>u  
fileSplitterFetch.start(); $"kPzo~B_  
} 3gi)QCsk  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), E^i]eK*"  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); :skR6J  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", aas.-NT  
nEndPos = " + nFileLength); v=N?(6T  
// fileSplitterFetch[nPos.length-1].start(); GD
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//等待子线程结束 ,L/x\_28  
//int count = 0; lgOAc,  
//是否结束while循环 _>- D*l  
boolean breakWhile = false; FO2e7p^Q  
vQEV,d1  
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while(!bStop) -* ,CMw  
{ $O%{l.-O  
write_nPos(); @[n#-!i  
Utility.sleep(500); rpT.n-H>%A  
breakWhile = true; W'[V
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for(int i=0;i<nStartPos.length;i++) XNJ4T]><  
{ t7+A!7b{  
if(!fileSplitterFetch.bDownOver) EA& 3rI>U)  
{ xl\Kj2^  
breakWhile = false;
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break; Jxe+LG  
} l[}4 X/  
} c2npma]DZ  
if(breakWhile) tq3_az ~1  
break; y}odTeq  
C ^Y\?2h1  
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//count++; 4V,.Oi  
//if(count>4) gF)9a_R%p  
// siteStop(); "%-Vrb=:Y  
} 5>x_G#W  
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System.err.println("文件下载结束！"); 8`q7Yss6F  
} _Iy\,<  
catch(Exception e){e.printStackTrace ();} 8%[pno |0I  
} @Wu-&Lb  
L:G#>  
d?2
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//获得文件长度 Y %JQ  
public long getFileSize() V'vR(Wx  
{ AcH-TIgM/  
int nFileLength = -1; H9cPtP~a)  
try{ @]=40Yj~w  
URL url = new URL(siteInfoBean.getSSiteURL()); WgtLKRZ\  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); $]2)r[eA)  
httpConnection.setRequestProperty("User-Agent","NetFox"); Y2H-D{a27  
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int responseCode=httpConnection.getResponseCode(); jj5S+ >4  
if(responseCode>=400) EApKN@<"  
{ Z>rY9VvWD  
processErrorCode(responseCode); nr!N%Hi  
return -2; //-2 represent access is error g52a vG  
} L44m!%q  
AJPvwu}D  
;P@]7vkff  
String sHeader; oUv26t~  
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for(int i=1;;i++) ,erw(7}'.  
{ @A/k"Ax{r  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 1vj/6L  
//Utility.log(in.readLine());  F!omkN  
sHeader=httpConnection.getHeaderFieldKey(i); 4U}qrN~=  
if(sHeader!=null) [0H0%z#tU&  
{ oo5=5s6 3}  
if(sHeader.equals("Content-Length")) c`a(  
{ d1j9{  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 2QfN.<[-  
break; drq3=2  
} ]R__$fl`8  
} )pnyVTKt  
else +&EXTZ@o  
break; FfoOJzf~o  
} zsFzg.$3&  
} ;XKe$fsa~?  
catch(IOException e){e.printStackTrace ();} mB?x_6#d9  
catch(Exception e){e.printStackTrace ();} .fA*WQ!lb  
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#+I'V\[  
Utility.log(nFileLength); kx
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return nFileLength; j)A#}4jd  
} {1W:@6tl  
ccD+AGM.  
WyL+HB}  
//保存下载信息（文件指针位置） Fnw:alWr  
private void write_nPos() Ha'[uEDb  
{ Rj8%% G-pt  
try{ P]_d;\ !"v  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 8%?y)K^ D  
output.writeInt(nStartPos.length); K1B9t{T  
for(int i=0;i<nStartPos.length;i++) MmuT~d/  
{ ^J!q>KJs  
// output.writeLong(nPos); bx@l6bpQ  
output.writeLong(fileSplitterFetch.nStartPos); V~J5x >O  
output.writeLong(fileSplitterFetch.nEndPos); qQ&uU7,#  
} -yYdj1y;  
output.close();
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} `8:0x?X  
catch(IOException e){e.printStackTrace ();} qUe _B  
catch(Exception e){e.printStackTrace ();} pSZ2>^";  
} 6cQgp]%  
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//读取保存的下载信息（文件指针位置） U|(+-R8Z  
private void read_nPos() d0cL9&~qW  
{ Qzi?%&  
try{ em$pU*`P  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); y_]+;%w:  
int nCount = input.readInt(); @ZKf3,J0  
nStartPos = new long[nCount]; mkl{Tp*  
nEndPos = new long[nCount]; ,$P,x  
for(int i=0;i<nStartPos.length;i++) FR&`
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{ _T=g?0 q  
nStartPos = input.readLong(); VFHd2Ea(  
nEndPos = input.readLong(); 4w4B\Na>l  
} YO6BzS/~  
input.close(); VJh8`PVX  
} SC{m@  
catch(IOException e){e.printStackTrace ();} 1J@Iekat  
catch(Exception e){e.printStackTrace ();} P&-o>mM  
} <Au2e  
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private void processErrorCode(int nErrorCode) niVR!l  
{ !xM5 A[f  
System.err.println("Error Code : " + nErrorCode); 7*/{mK)  
} 5=dL`  
B@,9Cx564  
k$EVr([  
//停止文件下载 K|& f5w  
public void siteStop()
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{ Mf}M/Fh  
bStop = true; wBPo{  
for(int i=0;i<nStartPos.length;i++) 8~sP{V%  
fileSplitterFetch.splitterStop(); )8Va%{j  
9 _d2u#  
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} xo:kT)  
} "L~(%Nx3  
//负责部分文件的抓取 6|TSH$w_  
**FileSplitterFetch.java b}J%4Lx%m  
*/ CSk]c9=  
package NetFox; 4#U}bN  
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import java.io.*; 1^iBS  
import java.net.*; ?b7\m":'  
7>JYwU{  
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public class FileSplitterFetch extends Thread { U=>S|>daR  
. ,7bGY 1$  
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String sURL; //File URL ~%{2Z_t$  
long nStartPos; //File Snippet Start Position n ]ikc|  
long nEndPos; //File Snippet End Position XtF m5\U  
int nThreadID; //Thread's ID DwD$T%kF  
boolean bDownOver = false; //Downing is over b7Y g~Lw  
boolean bStop = false; //Stop identical 74s{b]jN'-  
FileAccessI fileAccessI = null; //File Access interface @hLkU4S  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException \& JZ >h  
{ jDzQw>TX  
this.sURL = sURL; (8nv&|  
this.nStartPos = nStart; ]@q%d
sz  
this.nEndPos = nEnd; xNz(LZ.c  
nThreadID = id; #-hO\ QdC  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 v=`yfCX-qX  
} x2"iZzQlD  
8:cbr/F<  
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public void run() 5&Oc`5QD  
{ 4aayMS!#  
while(nStartPos < nEndPos && !bStop) Hl*v
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{ ^xo<$zn
 
.nV2n@SR  
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try{ 5/H,UL  
URL url = new URL(sURL); ,'#TdLe  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); |d
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httpConnection.setRequestProperty("User-Agent","NetFox"); 3"fDFR  
String sProperty = "bytes="+nStartPos+"-"; A_9WSXR  
httpConnection.setRequestProperty("RANGE",sProperty); f~IJ4T2#N  
Utility.log(sProperty); Z\0Rw>#  
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InputStream input = httpConnection.getInputStream(); _1" ecaA  
//logResponseHead(httpConnection); XTol|a=  
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byte[] b = new byte[1024]; J0G@]H  
int nRead; ">uN={Iy  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) z^Q'GBoBA  
{ [K{{P|(q  
nStartPos += fileAccessI.write(b,0,nRead); y@P%t9l  
//if(nThreadID == 1) De$AJl  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); "W<Y1$Y=Y  
} 5=>1>HYM  
9>}&dQ8  
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Utility.log("Thread " + nThreadID + " is over!"); b F=MQ  
bDownOver = true; s.3"2waZ=T  
//nPos = fileAccessI.write (b,0,nRead); 3G})$y3m  
} ,5DJ54B!  
catch(Exception e){e.printStackTrace ();} b|#=kPVgL}  
} A^U84kV=  
} 'C+cQLig@  
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//打印回应的头信息 hU)t5/h;K  
public void logResponseHead(HttpURLConnection con) %Ymi,o>  
{ HB07 n4 |  
for(int i=1;;i++) =C %)(|  
{ bQ<qdGa  
String header=con.getHeaderFieldKey(i); <'y<8gpM  
if(header!=null) }\4yU=JPK  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); AGhenDNV  
Utility.log(header+" : "+con.getHeaderField(header)); *X5)9dq  
else Pz4#>tP  
break; "k
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} *D5 xbkH=.  
} blc?[ [,!  
[-~pDkf:  
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public void splitterStop() {gMe<y  
{ k %I83,+  
bStop = true; 8
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} ]ua3I}_B6v  
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} ]uXJjS f  
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Z
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/* V"Q\7,_k.  
**FileAccess.java <z Gh}.6v  
*//文件访问(定位，写) E^8|xT'h6  
package NetFox; D 0Xl`0"'  
import java.io.*; p1N}2]e  
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;
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public class FileAccessI implements Serializable{ y^2#;0W  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 VKa+[  
RandomAccessFile oSavedFile; *V>?m6y/  
long nPos; F:j@JMpQ  
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h nydH-;cz  
public FileAccessI() throws IOException *ug~LK5Y.  
{ v^"\e&XL  
this("",0); E@VQxB7+  
} (s8b?Ol/  
J[/WBVFDf  
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public FileAccessI(String sName,long nPos) throws IOException S-t#d7'B  
{ *-VRkS-G  
oSavedFile = new RandomAccessFile(sName,"rw"); eORXyh\K  
this.nPos = nPos; k1&9 bgI  
oSavedFile.seek(nPos); `46~j  
} g`fG84  
*s6x  
zs$r>rlO  
public synchronized int write(byte[] b,int nStart,int nLen) G e;67  
{ }'[>~&/"  
int n = -1; 7QO/; zL  
try{ G
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oSavedFile.write(b,nStart,nLen); _^ hg7&dF  
n = nLen; W>3S%2d  
} -^&=I3bp  
catch(IOException e) hSehJjEoM  
{ :{u`qi  
e.printStackTrace (); |q`NJ  
} dT|XcVKg  
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return n; ~yv7[`+Tgg  
} b]u$!W  
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} *)m:u:  
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/* ?N kKDvv  
**SiteInfoBean.java ^'3c%&Zf3  
*/ jY6GWsh:9  
package NetFox; %QP[/
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*_D/_Rp7  
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public class SiteInfoBean { MA .;=T  
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private String sSiteURL; //Site's URL 2w|5SK_  
private String sFilePath; //Saved File's Path n%E,[JT  
private String sFileName; //Saved File's Name /HIyQW\Ki-  
private int nSplitter; //Count of Splited Downloading File %.Y5%TyP  
9f~qD&~  
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public SiteInfoBean() *p/,Z2f  
{//nSplitter的缺省值为5 ^h?fr`  
//default value of nSplitter is 5 G'|ql5Zw  
this("","","",5); Q68~D.V%r  
} C?qRZB+W#  
xG!~TQ  
^ `LqNG  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) P2n8HFi  
{ cSL6V2F  
sSiteURL= sURL; IQ_6DF  
sFilePath = sPath; ; Y/nS  
sFileName = sName; j!+jLm!l  
this.nSplitter = nSpiltter; %q5dV<X'c  
[,;Y5#Y[5  
!*]i3 ,{7v  
} 4DL;Y  
SZGR9/*^  
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public String getSSiteURL() ns~]a:1yh  
{ ?%3dgQB'  
return sSiteURL; ; Z:[LJd  
} @i ~A7L0/  
+4yre^gC  
`v-[&  
public void setSSiteURL(String value) "Enb   
{ 4cQP+n  
sSiteURL = value; KV0*dB;  
} e!6yxL*[@[  
 Bx45yaT  
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public String getSFilePath() bM?gAY]mB8  
{ 7O1MC 8{  
return sFilePath; 8N&'n  
}
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XG|N$~N+2  
} =OE.cf@  
public void setSFilePath(String value) Kx9u|fp5  
{ y:)^*2GA-B  
sFilePath = value; *JK0X  
} ]:e_Y,@  
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public String getSFileName() L:HvrB
~  
{ B[8bkFS>]  
return sFileName; s{b\\$Rb  
} Jc":zR@
5  
^N7H~CT"  
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public void setSFileName(String value) 8"%Es  
{ Q6m8N
 
sFileName = value; q|*^{(tWs  
} $0$sM/%  
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0AHQ(+Ap  
public int getNSplitter() tV!?Ol  
{ t:2DB)  
return nSplitter; $udhTI#,  
} 44KoOY_  
4jXo5SkEJ  
& /8Tth86  
public void setNSplitter(int nCount) 40?RiwwD  
{ mx^Ga=: ?  
nSplitter = nCount; \3hA_{ w  
} T'pL&@,Q  
} m-t:'B  
)Qb,zS6  
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/* #*bmwb*i  
**Utility.java y#'hOSR2  
*/ )$]lf }  
package NetFox; 4r(0+SO  
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\Th<7WbR6#  
public class Utility { y,5qY}P+  
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/\%<VBx ?q  
public Utility() rZ?:$],U!  
{ JpS}X\]i  
JP4DV=}L  

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} ET.jjV  
c)#P}Ai  
//线程睡眠 X+!+&RAN*  
public static void sleep(int nSecond) JmCMFqB9  
{ DFMpU.BN W  
try{ uzdPA'u  
Thread.sleep(nSecond); T^ktfgXq  
} :)#;0o5  
catch(Exception e) $z=%e#(!I  
{ 7}&:07U  
e.printStackTrace (); u%C oo  
} n#+EG3  
} F` ybe\  
xFF!)k #  
//日志 v@zi?D K  
public static void log(String sMsg) BpIyw  
{ 4]r_K2.cc  
System.err.println(sMsg); M!,H0(@G  
} D|q~n)TW5  
_)45G"M  
O|H:  
public static void log(int sMsg) &vrQ *jX  
{ s70Z&3A  
System.err.println(sMsg); DMUirA;  
} +Kk1[fh-  
} 8n3]AOc'~-  
poBeEpbs  
6nTM~]5.  
/* WJq>%<#  
**TestMethod.java c9+G Qp  
*/ j*>J1M3E  
package NetFox; [1rQ'FBB^1  
=muQ7l:(  
"'CvB0>  
public class TestMethod { |<Ls;:5.  
-m@c{&r  
 Qxz[  
public TestMethod() h  /  
{ ///xx/weblogic60b2_win.exe _r-LX"  
try{  w*`:v$  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); z_>~=Mm  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); v +4v  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 2W+~{3[#  
fileFetch.start(); vzSb(  
} DvH-M3  
catch(Exception e){e.printStackTrace ();} W_B=}lP@x  
g@#he95 }  
+RJ{)Nec  
} 0%bCP/  
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l>\EkUT  
public static void main(String[] args) ^BF}wQb:j  
{ &ZD@-"@  
new TestMethod(); 8xB-cE  
} u[)X="-e#  
} m4m-JD|v  
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