http断点续传简单实现（java)

/* qqe2
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**SiteFileFetch.java Y%/ YFO2vb  
*/ f#v#)Gp+  
package NetFox; ]<q}WjXD'  
import java.io.*; 7rdw`  
import java.net.*; L%WME8PB  
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public class SiteFileFetch extends Thread { jJUGZVM6)  
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SiteInfoBean siteInfoBean = null; //文件信息Bean /^'Bgnez  
long[] nStartPos; //开始位置 U=kx`j>  
long[] nEndPos; //结束位置 *qPdZ  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Uvh~B^6  
long nFileLength; //文件长度 CZyz;Jtk  
boolean bFirst = true; //是否第一次取文件 .kc"E  
boolean bStop = false; //停止标志 0iJ!K;A2%  
File tmpFile; //文件下载的临时信息 fVDDYo2\  
DataOutputStream output; //输出到文件的输出流 jC%35bi  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ufw3H9F(O  
public SiteFileFetch(SiteInfoBean bean) throws IOException z.3<{-n}0i  
{ Qz@IK:B}  
siteInfoBean = bean; oTCzYY  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); `/O`OrZ1K  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Tm)GC_  
if(tmpFile.exists ()) OJP5k/U$  
{ <b d1  
bFirst = false; 8K0X[-hs8  
read_nPos(); q^a|
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} D<U 9m3  
else bmOqeUgB  
{ OXHvT/L`  
nStartPos = new long[bean.getNSplitter()]; C$<"w,  
nEndPos = new long[bean.getNSplitter()]; VEj$^bpp5s  
} S]&8St  
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} O' +"d%2'  
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public void run() Kt W6AZJ  
{ "z^(dF|  
//获得文件长度 q,B3ru.?d  
//分割文件 e>l,(ql  
//实例FileSplitterFetch i:o}!RZ>  
//启动FileSplitterFetch线程 ZFS7{:  
//等待子线程返回
nbI=r+  
try{ A4G,}r *n  
if(bFirst) (CdJ;-@D  
{ VF)uu[ f9  
nFileLength = getFileSize(); Y1{B c<tC  
if(nFileLength == -1) D ]OD.  
{ HA6G)x  
System.err.println("File Length is not known!"); .
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} QsiJ%O Q  
else if(nFileLength == -2) Q}kfM^i  
{ P+<BOG|m  
System.err.println("File is not access!"); ^P`NMSw  
} wV\%R,bZj  
else iF!mV5#  
{ Sd},_Kh  
for(int i=0;i<nStartPos.length;i++) /X4yB"J>  
{ zfhTc=(/  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ?c!:81+\  
} Q48+O?&  
for(int i=0;i<nEndPos.length-1;i++) F4Zn5&.)  
{ 3VmI0gsm.>  
nEndPos = nStartPos[i+1]; b~7Jh:%@;  
} 1Cm~X$S.  
nEndPos[nEndPos.length-1] = nFileLength; %*lp< D  
} Q1Ux!$_  
} E&*: jDg  
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//启动子线程 '>@4(=I  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; V vu(`9u]  
for(int i=0;i<nStartPos.length;i++) |h}B{D  
{ <FY&h#  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), x(8n 9Q>  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), >1 @Ltvm  
nStartPos,nEndPos,i); `
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Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ueDvMP  
fileSplitterFetch.start(); St@l]u9  
} Ekv89swl`i  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), <I;5wv  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); B2 c@kru  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", e,HMwD  
nEndPos = " + nFileLength); j{"z4Y4  
// fileSplitterFetch[nPos.length-1].start(); +$47v$p
 
}j4
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//等待子线程结束 P z ?m>>#  
//int count = 0; 1dFa@<5  
//是否结束while循环 +\0T\;-Xe  
boolean breakWhile = false; OL'P]=U  
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while(!bStop) |uI?ySF  
{ =m7H)z)i*J  
write_nPos(); igDG}q3jG  
Utility.sleep(500); `>6T&  
breakWhile = true; a2`%ghW3  
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for(int i=0;i<nStartPos.length;i++) =O!|IAe#  
{ @x1%)1  
if(!fileSplitterFetch.bDownOver) !Xj#@e  
{ qI%&ay"/  
breakWhile = false; .2.qR,"j  
break; u-JpI-8h  
} #)s!}X^  
} { p;shs5  
if(breakWhile) 3e%nA8?  
break; FJeiY#us  
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//count++; 3J~0O2  
//if(count>4) W@.Ji B  
// siteStop(); j8++R&1f]  
} f'X9HU{Cz  
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System.err.println("文件下载结束！"); 2N5`'  
} e_.Gw"/Yl  
catch(Exception e){e.printStackTrace ();} :^i^0dC  
} rh!;|xB|+  
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//获得文件长度 p@~ic#X  
public long getFileSize() P
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{ >oGiIYq  
int nFileLength = -1; _V2xA88
 
try{ |A\a4f'G  
URL url = new URL(siteInfoBean.getSSiteURL()); "?3`  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); #Exp51  
httpConnection.setRequestProperty("User-Agent","NetFox"); ;),"M{"v  
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int responseCode=httpConnection.getResponseCode(); jq-l5})h  
if(responseCode>=400) h|D0z_f  
{ ;W]\rft[  
processErrorCode(responseCode); +lE90y  
return -2; //-2 represent access is error 8)L*AdDAW!  
} /@"Y^  
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String sHeader; s@8w-]"  
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for(int i=1;;i++) 3Fs5RC~a  
{ X6\ sF"E  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); CrC=A=e  
//Utility.log(in.readLine()); H1/?+N}(  
sHeader=httpConnection.getHeaderFieldKey(i); B07v^!Z>  
if(sHeader!=null) YJ_\Ns+Ow  
{ zmI]cD@G  
if(sHeader.equals("Content-Length")) *JX;|S  
{ z//VlB  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ?'s6Xmd  
break; - +>1r  
} :o46rBs  
} q?):oJ  
else 1yQejw  
break; =LkR!R=  
} 'Gl&Pa1g?  
} C0jj(ku&  
catch(IOException e){e.printStackTrace ();} }}&#|)Yq  
catch(Exception e){e.printStackTrace ();} GZip\S4Y  
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Utility.log(nFileLength); piy`zc-yu  
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return nFileLength; 3
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} 30>3 !Xqa
 
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//保存下载信息（文件指针位置） #]P9b@@e  
private void write_nPos() nUS| sh  
{ !3X0FNGq  
try{ y5r4+2B  
output = new DataOutputStream(new FileOutputStream(tmpFile)); T 20&F  
output.writeInt(nStartPos.length); -I.d}[  
for(int i=0;i<nStartPos.length;i++) t.p~\6
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{ 5Xn.CBd]  
// output.writeLong(nPos); 8[vc?+>&  
output.writeLong(fileSplitterFetch.nStartPos); @$9'@")  
output.writeLong(fileSplitterFetch.nEndPos); F$BbYf2i  
} */:uV B,b2  
output.close(); >-8cU_m7s  
} 6;'dUGvH  
catch(IOException e){e.printStackTrace ();} qz?mh4Oh  
catch(Exception e){e.printStackTrace ();} M(x$xAiD  
} b~=0[Rv  
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//读取保存的下载信息（文件指针位置） &>d:R_Q]  
private void read_nPos() ApBWuXp|u  
{ F8-?dpf'  
try{ R^?/' dr  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 2c6g>?  
int nCount = input.readInt(); #Cpd9|  
nStartPos = new long[nCount]; ?;[w
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nEndPos = new long[nCount]; wLc4Dm*V  
for(int i=0;i<nStartPos.length;i++) 1 zw*/dp  
{ Ym%xx!9  
nStartPos = input.readLong(); wE+${B03  
nEndPos = input.readLong(); .*m>\>Gsgw  
} 7d LuX   
input.close(); ;AO#xv+#  
} IxLhU45  
catch(IOException e){e.printStackTrace ();} q9Y9w(  
catch(Exception e){e.printStackTrace ();} .7K7h^*F  
} `]Q:-h  
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private void processErrorCode(int nErrorCode) q`-;AG|xF  
{ /1Ue?)g  
System.err.println("Error Code : " + nErrorCode); X 1 57$  
} okbQ<{9  
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//停止文件下载 }gJ(DbnV  
public void siteStop() T5a*z}L5  
{ h1'\:N`  
bStop = true; lpz2 m\  
for(int i=0;i<nStartPos.length;i++) PRHCrHs  
fileSplitterFetch.splitterStop(); Fu!RhsW5j  
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} dFKM 8_jH  
} sI{ M  
//负责部分文件的抓取 phM>.y_  
**FileSplitterFetch.java |*}4 m'c  
*/ BD(Z5+EU1  
package NetFox; L4!{h|  
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import java.io.*; 1t)il^p4[;  
import java.net.*; Y "/]|'p  
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public class FileSplitterFetch extends Thread { 7(pF[LCF  
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String sURL; //File URL dq]0X?[6  
long nStartPos; //File Snippet Start Position rzt Ru  
long nEndPos; //File Snippet End Position ZIQ [bE7  
int nThreadID; //Thread's ID %}%Qc6.H  
boolean bDownOver = false; //Downing is over Z]B~{!W1  
boolean bStop = false; //Stop identical @nux9MX
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FileAccessI fileAccessI = null; //File Access interface v%q0OX>9X"  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException HS
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{ 1fpQLaT  
this.sURL = sURL; 8P|D13- Q  
this.nStartPos = nStart; DAXX;4  
this.nEndPos = nEnd; e J6$-r  
nThreadID = id; q^Y-}=w  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 'IwNTM  
} <ZNzVnVA  
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public void run() y!_C/!d  
{ [5SD_dN  
while(nStartPos < nEndPos && !bStop) z*a:L}$  
{ MB]<Dyj,  
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try{ |>dI/_'  
URL url = new URL(sURL); fTK3,s1=  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ?`PvL!'  
httpConnection.setRequestProperty("User-Agent","NetFox"); lE4HM$p
 
String sProperty = "bytes="+nStartPos+"-"; $w`=z<2yo1  
httpConnection.setRequestProperty("RANGE",sProperty); =`H@%  
Utility.log(sProperty); 'F9jq  
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InputStream input = httpConnection.getInputStream(); Xg;}R:g '  
//logResponseHead(httpConnection); cWe"%I  
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byte[] b = new byte[1024]; VgZsB$Ori  
int nRead; q1d}{DU  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 9,:l8  
{ F^];U+J  
nStartPos += fileAccessI.write(b,0,nRead); <+?7H\b  
//if(nThreadID == 1) mc? Vq  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); dtRwTUMe?  
} woGAf)vV#  
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Utility.log("Thread " + nThreadID + " is over!"); $#9;)8J  
bDownOver = true; .uMn0PE   
//nPos = fileAccessI.write (b,0,nRead); o<pf#tifv  
} +|n*b  
catch(Exception e){e.printStackTrace ();} JR@`2YP-  
} hG12ZZD  
} EVsC>rz  
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//打印回应的头信息 VJ]JjB j  
public void logResponseHead(HttpURLConnection con) CVL3VT1j0  
{ T[UN@^DP(  
for(int i=1;;i++) svcK?^ HTe  
{ 5YeM%%-S  
String header=con.getHeaderFieldKey(i); I 8`VNA&b  
if(header!=null)  3KlbP  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); gd`!tRcNY  
Utility.log(header+" : "+con.getHeaderField(header)); i@"@9n~  
else M_/7D|xl/T  
break; q_A!'sm@)  
} Vt:~q{9*k  
} iTgt}]L  
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public void splitterStop() 4%>$-($  
{ s(/;U2"e  
bStop = true; ^/I 7|u]  
} 7&jTtKLj  
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} zPn+V7F  
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+
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/* qouhuH_WtJ  
**FileAccess.java ! >(7+B3E*  
*//文件访问(定位，写) #Z?A2r!1  
package NetFox; xpV|\2C  
import java.io.*; pjKWtY@=X  
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#+ 0M2Sa  
public class FileAccessI implements Serializable{ 4":KoS`,j  
} gyj0  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 p& y<I6a,  
RandomAccessFile oSavedFile; ey7 f9  
long nPos; c}lb%^;)E  
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public FileAccessI() throws IOException Aza /6OL  
{ 4KhV|#-;k  
this("",0);
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} [kVS O  
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public FileAccessI(String sName,long nPos) throws IOException [M]  
{ Q 3hKk$Y  
oSavedFile = new RandomAccessFile(sName,"rw");
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this.nPos = nPos; -;s|  
oSavedFile.seek(nPos); u%&`}g  
} ^S4d:-.3  
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public synchronized int write(byte[] b,int nStart,int nLen) SE@LYeC}dE  
{ (5$!MUS~9  
int n = -1; =)0,#9k U]  
try{ n,vct<&z@  
oSavedFile.write(b,nStart,nLen); \:%(q/v"X  
n = nLen; sXLq*b?  
} F&4rO\aC"/  
catch(IOException e) yZ0-wI  
{ ^n*)7K[  
e.printStackTrace (); }^ApJS(FQ  
} {fPy=,>Nb  
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return n; ;km`P|
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} wL+s8#{  
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} 3@etRd;]Kr  
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"  
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/* K^ vIUZ>  
**SiteInfoBean.java Y+kfBvxyf  
*/ g#"zQvON  
package NetFox; L O}@dL  
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public class SiteInfoBean { {BP{C=p  
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private String sSiteURL; //Site's URL 3atBX5  
private String sFilePath; //Saved File's Path vNyf64)  
private String sFileName; //Saved File's Name Zd3S:),&  
private int nSplitter; //Count of Splited Downloading File Gj1&tjK  
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public SiteInfoBean() `LrHKb aP  
{//nSplitter的缺省值为5 DBo%fYst  
//default value of nSplitter is 5 \Z?9{J  
this("","","",5); ~uj#4>3T  
} 6|gCuT4  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) g{7.r-uu  
{ _'#n6^Us<  
sSiteURL= sURL; B7VH<;Z  
sFilePath = sPath; Uf1!qP/H?  
sFileName = sName; `fA@hK   
this.nSplitter = nSpiltter; RFi S@.7  
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&xU[E!2H%  
} C(eTR1  
?j'7l=94A  
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public String getSSiteURL() iJ ($YvF4  
{ Y[ j6u\y  
return sSiteURL; f&=AA@jLv  
} XPavReGf  
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public void setSSiteURL(String value) .r|tSfm6  
{ &pP;Neh;  
sSiteURL = value; 034iK[ib"  
} |T<_5Ik  
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public String getSFilePath() /74QMx?  
{ ;nI] !g:  
return sFilePath; 0%32=k7O[  
} ]V[q(-Jk  
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public void setSFilePath(String value) fZ6MSAh  
{ yjO1 Ol  
sFilePath = value; .Hescg/S  
} \Q {m9fE  
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public String getSFileName() B+$%*%b  
{ n"h`5p5'  
return sFileName; MH =%-S   
} OstQqV%@  
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public void setSFileName(String value) O+nEXS\rQ  
{ jkQ*D(;p  
sFileName = value; t^UxR@l<K|  
} ud63f`W]4  
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public int getNSplitter() ~jWn4 \  
{ @CNi{. RX
 
return nSplitter; bc7/V#W  
} 3BzNi'  
!-g{[19\  
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public void setNSplitter(int nCount) <S5BDk  
{ UgRhWV~f0  
nSplitter = nCount;  |{&{  
} d}OTO10  
} ,xw#NG6  
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/* !({}(!P .  
**Utility.java a`wc\T^
 
*/ FW;m\vu  
package NetFox; , |0}<%  
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public class Utility {
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public Utility() \0A3]l  
{ hl;u'_AB  
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} [Hx0`Nc K  
0}<|7?  
//线程睡眠 3t.l5m Rg5  
public static void sleep(int nSecond) Z3%}ajPu[  
{ #^#PP
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try{ CVDV)#JA  
Thread.sleep(nSecond); 36.Z0Z1'F>  
} _PPy44r2  
catch(Exception e) 2"COP>  
{ MO[2~`,Q!  
e.printStackTrace (); q~rEq%tk  
} QER?i;-wb  
} H h4WMZJG  
at@G/?  
//日志 *$#W]bO  
public static void log(String sMsg) <g-9T-Ky  
{ .Q<>-3\K  
System.err.println(sMsg); "x%Htq@  
} 3v(*5  
=-tw5], L  
3\AU 72-  
public static void log(int sMsg) YP 6`L  
{ -<6\1J  
System.err.println(sMsg); } j<)L,  
} __uA}fZp  
} _,
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:{{F *FM;  
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/* rr/B=O7  
**TestMethod.java XWnVgY s  
*/ N1}c9}  
package NetFox; MlcR"gl*  
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|U~<3.:m:  
public class TestMethod { lVd^ ^T*fh  
*FWMn.  
+2(I1  
public TestMethod() iyN:%ofh  
{ ///xx/weblogic60b2_win.exe 'Jiw@t<o3`  
try{ 9y6-/H ,  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ,y1PbA0m  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); # q~e^A b  
SiteFileFetch fileFetch = new SiteFileFetch(bean); xg30xC[  
fileFetch.start(); Gw=B:kGk  
} ?yZ+D z\  
catch(Exception e){e.printStackTrace ();} N%kt3vmQ_  
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} #||}R[~P"  
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public static void main(String[] args) m&xW6!x  
{ Y)1PB+  
new TestMethod(); lvdf^b/ j  
} A8x
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} P|^f0Rw3.  
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