http断点续传简单实现（java)

/* I3xx}^V  
**SiteFileFetch.java .Lrdw3(  
*/ `@{qnCNQ  
package NetFox; A$RN7#  
import java.io.*; Ms*;?qtrR  
import java.net.*; *xs8/?  
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public class SiteFileFetch extends Thread { P 7 [p$Z
 
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SiteInfoBean siteInfoBean = null; //文件信息Bean yZaQ{]"  
long[] nStartPos; //开始位置 x3L3K/qMg  
long[] nEndPos; //结束位置 $-VW)~Sl  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 SvH=P!`+  
long nFileLength; //文件长度 l_LfVON  
boolean bFirst = true; //是否第一次取文件 AA}M"8~2  
boolean bStop = false; //停止标志 O{rgZ/4Au  
File tmpFile; //文件下载的临时信息 Rww"Z=F  
DataOutputStream output; //输出到文件的输出流 r+HJ_R,5A  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） >Lanuv)O  
public SiteFileFetch(SiteInfoBean bean) throws IOException `xkJ.,#Io  
{ kTG
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siteInfoBean = bean; r]'AdJFt  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); \z8TYx@  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Z94D<X"  
if(tmpFile.exists ()) kX{c+qHM  
{ ^!|BKH8>f%  
bFirst = false; WKpHb:H  
read_nPos(); 6
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} K/Axojo  
else G7C9FV bR  
{ x>5#@SX J  
nStartPos = new long[bean.getNSplitter()]; $cH'9W}3K  
nEndPos = new long[bean.getNSplitter()]; Tk/K7h^  
} *Yov>lO  
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} -4b9(  
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public void run() kaUH#;c>_  
{ =#1iio&  
//获得文件长度 D6_16PJE  
//分割文件 dOqwF iO  
//实例FileSplitterFetch xJ%b<y{@  
//启动FileSplitterFetch线程 8Md*9E#J("  
//等待子线程返回 <"CG%RGP  
try{ 0_Etm83Wq6  
if(bFirst) dW!T.S
 
{ e&F,z=XJ}  
nFileLength = getFileSize(); ? Z8_(e0U  
if(nFileLength == -1) av wU)6L  
{ RKIqg4>E  
System.err.println("File Length is not known!"); QsI>_<r  
} ,[+gE\z{{u  
else if(nFileLength == -2) vC\]7]mC  
{ b#k$/A@  
System.err.println("File is not access!"); R^dAwt`.D  
} 2hf]XV\  
else  2c!?!:s  
{ vyqlP;K  
for(int i=0;i<nStartPos.length;i++) ^l_W9s  
{ BWL~)Hx  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); qVJV9n  
} IcPIOCmOc  
for(int i=0;i<nEndPos.length-1;i++) $9*Xfb
/  
{ :!3CoC.X|c  
nEndPos = nStartPos[i+1]; i/oaKpPN  
} S! ,.#e(Y  
nEndPos[nEndPos.length-1] = nFileLength; EEn}Gw  
} ~|Gtm[9Ru  
} !=cW+=1  
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//启动子线程 v"_hWJ)  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; &hd+x5  
for(int i=0;i<nStartPos.length;i++) YG?W8)T  
{ #)=P/N1  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), rq}ew0&/  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), bbiDY  
nStartPos,nEndPos,i); $}W=O:L+D  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ;% !'K~  
fileSplitterFetch.start(); nd_d tsp#  
} GRO[&;d`  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), OMO.-p  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); u Dm=W36  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", &bs/a]?Z7  
nEndPos = " + nFileLength); .0.Ha}{6b  
// fileSplitterFetch[nPos.length-1].start(); gGe `w  
|nz,srr~  
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//等待子线程结束 gjL>FOe8u  
//int count = 0; lXW.G  
//是否结束while循环 (Pc:A!}  
boolean breakWhile = false; *"O7ml
]  
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while(!bStop) :%xiH%C>  
{ gHvxmIG  
write_nPos(); /S\P=lcb  
Utility.sleep(500); 1/6G&RB  
breakWhile = true; vy1:>N?#5  
id&;

 
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for(int i=0;i<nStartPos.length;i++) Z!~~6Sq  
{ sh:sPzQ%Jv  
if(!fileSplitterFetch.bDownOver) ga6M8eOI  
{ >=6tfLQ  
breakWhile = false; l>7`D3  
break; =4m?RPb~b  
} JQi)6A?J  
} ggJn oL  
if(breakWhile) O|?>rK  
break; ~F+{P4%`<  
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//count++; B Lw ssr.  
//if(count>4) <k6Zx-6X<  
// siteStop(); ZnI_<iFR*  
} F^3Q0KsT  
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System.err.println("文件下载结束！"); dilRL,  
} M7fw/i  
catch(Exception e){e.printStackTrace ();} *s S7^OZ*  
} %W+*)u72(  
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//获得文件长度 z6A
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public long getFileSize() u! x9O8y  
{ +i4S^B/8i  
int nFileLength = -1; #fRhG^QKp  
try{ 4nXS}bWf  
URL url = new URL(siteInfoBean.getSSiteURL()); "qIO,\3T  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); lBgf' b3$  
httpConnection.setRequestProperty("User-Agent","NetFox"); @i$9c)D  

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int responseCode=httpConnection.getResponseCode(); /al(=zf  
if(responseCode>=400) 1ePZs$   
{ l~!\<, !  
processErrorCode(responseCode); /3L1Un*  
return -2; //-2 represent access is error #dtYa  
} JC_Y#kN@z  
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String sHeader; 4=%Uv^M  
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for(int i=1;;i++) =^|^"
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{ Zq}w}v  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); V; Yl:*  
//Utility.log(in.readLine()); z\sy~DM;>  
sHeader=httpConnection.getHeaderFieldKey(i); 8G6PcTqv"  
if(sHeader!=null) .Xc, Gq{  
{ +=)< Su.  
if(sHeader.equals("Content-Length")) cWA9n}Z  
{ #Ne<=ayS  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 2+s_*zM-  
break; SWNi@  
} |ITp$_S  
} {W)Kz_  
else " 2Dz5L1v  
break; (Ub=sC  
} N&]v\MjI62  
} M$B
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catch(IOException e){e.printStackTrace ();} _*>bf G  
catch(Exception e){e.printStackTrace ();} +\fr3@Yc  
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Utility.log(nFileLength); m$ )yd~  
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return nFileLength; me_DONW  
} =!w5%|r.  
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//保存下载信息（文件指针位置） '_lyoVP  
private void write_nPos() zH0%; o}  
{ puF'w:I(  
try{ &=Gz[1 L  
output = new DataOutputStream(new FileOutputStream(tmpFile)); >XcbNZV  
output.writeInt(nStartPos.length); W2D^%;mw  
for(int i=0;i<nStartPos.length;i++) GpMKOjVm|  
{ AON";&dLq-  
// output.writeLong(nPos); HgvgO\`]  
output.writeLong(fileSplitterFetch.nStartPos); ?l!L )!2  
output.writeLong(fileSplitterFetch.nEndPos); ig4wwd@|  
} %0fF
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output.close(); `KqMcAW  
} Dd-
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catch(IOException e){e.printStackTrace ();} +FfT)8@W  
catch(Exception e){e.printStackTrace ();} d rnqX-E;  
} 5+vCuVZ  
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//读取保存的下载信息（文件指针位置） jV]'/X<  
private void read_nPos() 3FT%.dV^  
{ ^1s!OT Is  
try{ )G\23P  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 1P#bR`I >  
int nCount = input.readInt(); 1L]7*NJe  
nStartPos = new long[nCount]; WPygmti}Be  
nEndPos = new long[nCount]; G~1#kg  
for(int i=0;i<nStartPos.length;i++) nd3=\.(P  
{ g0
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nStartPos = input.readLong(); rlT[tOVAY  
nEndPos = input.readLong(); XSyCT0f08  
} PVP,2Yq!  
input.close(); %C\Q{_AS  
} QZB2yK3]h  
catch(IOException e){e.printStackTrace ();} ^m;dEe&@F  
catch(Exception e){e.printStackTrace ();} ` wuA}v3!  
} ?VrZ
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private void processErrorCode(int nErrorCode) q>/# P5V  
{ 8Y*SZTzV  
System.err.println("Error Code : " + nErrorCode); $e&( ncM  
} l>`N+ pZ$  
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)SQ*"X4"  
//停止文件下载
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public void siteStop() L+LxS|S+M  
{ Vc.A
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bStop = true; Rp4EB:*  
for(int i=0;i<nStartPos.length;i++) !%5ae82~3  
fileSplitterFetch.splitterStop(); 4!p~Mr[E  
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} RIOR%~U  
} F,Y@  
//负责部分文件的抓取 +M
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**FileSplitterFetch.java -}`ES]  
*/ rUEoz|e4a  
package NetFox; @
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import java.io.*; py`RH)  
import java.net.*; F(
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public class FileSplitterFetch extends Thread { R#i|n<x  
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String sURL; //File URL `,i'vb`W#b  
long nStartPos; //File Snippet Start Position fZL%H0&  
long nEndPos; //File Snippet End Position zvf:*Na")  
int nThreadID; //Thread's ID ;F9<Yv  
boolean bDownOver = false; //Downing is over oEbgyT gB  
boolean bStop = false; //Stop identical |Ak>kQJ(1z  
FileAccessI fileAccessI = null; //File Access interface P1;T-.X~&  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException MzT#1~  
{ \?c0XD  
this.sURL = sURL; "u5Hm ^H  
this.nStartPos = nStart; .CdaOWM7  
this.nEndPos = nEnd; 4J0{$Xuu0  
nThreadID = id; ?P@fV'Jo  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ztf VXmi'  
} Bzn{~&i?W:  
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public void run() /tl/%:U*.  
{ _5%SYxF*y  
while(nStartPos < nEndPos && !bStop) s,m+q)  
{ kF.!U/C  
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try{ O&l
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URL url = new URL(sURL); *')BP;|V`  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); p8K4^H  
httpConnection.setRequestProperty("User-Agent","NetFox"); hm3,?FMbq  
String sProperty = "bytes="+nStartPos+"-"; O=LS~&=,  
httpConnection.setRequestProperty("RANGE",sProperty); jIJVl \i]  
Utility.log(sProperty); 4v9z
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InputStream input = httpConnection.getInputStream(); V2sWcV?  
//logResponseHead(httpConnection); !Rk1q&U5  
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byte[] b = new byte[1024]; 6eE%x?#  
int nRead; In^MZ)?  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) "}Kvx{L8  
{ dl;~-'0  
nStartPos += fileAccessI.write(b,0,nRead); p 2xOjS1  
//if(nThreadID == 1) *F*c  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); D5fJuT-bp  
} EW*
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Utility.log("Thread " + nThreadID + " is over!"); au7%K5  
bDownOver = true; .+>w0FG.  
//nPos = fileAccessI.write (b,0,nRead); :,"dno7OQ  
} )hmU/E@  
catch(Exception e){e.printStackTrace ();} geU-T\1[l  
} i3t=4[~oL  
} LSb3w/3M  
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r)Ts(#Z  
//打印回应的头信息 }Uki)3(  
public void logResponseHead(HttpURLConnection con) r|4jR6%<'m  
{ BM=`zGh"  
for(int i=1;;i++) t^ LXGQ  
{ c_c]0Tm  
String header=con.getHeaderFieldKey(i); ;tTM3W-h  
if(header!=null) ,!t1( H  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); B04%4N.g"X  
Utility.log(header+" : "+con.getHeaderField(header)); %41dVnWB^4  
else 6l&m+!i  
break; -q' np0H  
} jUtrFl  
} 16/+ O$#y  
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public void splitterStop() KK4>8zGR  
{ 1rh\X[@  
bStop = true; Onb*nm  
}  hh<5?1  
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p 7IJ3YY  
} loN!&YceW  
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/* %HSS x+2oR  
**FileAccess.java #S2LQ5U  
*//文件访问(定位，写) @QI]P{  
package NetFox; k1Zu&4C\  
import java.io.*; Oh6_Bci  
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public class FileAccessI implements Serializable{ qd{o64;|  
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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 #n%?}  
RandomAccessFile oSavedFile; nN>D=a"&F  
long nPos; 3U<\y6/  
o/buU{)y  
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public FileAccessI() throws IOException S+>&O3m  
{ `%;nHQ"  
this("",0); MK9?81xd  
} Fn$/ K  
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public FileAccessI(String sName,long nPos) throws IOException f/Km$#xOr  
{ jENarB^As  
oSavedFile = new RandomAccessFile(sName,"rw"); cd{3JGgB  
this.nPos = nPos; !+& NG&1  
oSavedFile.seek(nPos); h9
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} Ht? u{\p@  
C.L5\"%  
,{ CgOz+Ul  
public synchronized int write(byte[] b,int nStart,int nLen) VOwt2&mZ  
{ ?2[=llS4  
int n = -1; y2>v'%]2  
try{ T~8`{^  
oSavedFile.write(b,nStart,nLen); AbUU#C7  
n = nLen; 8OH<ppi  
} ASY 
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catch(IOException e) 6CO>Tg:%  
{ /k<*!H]KSg  
e.printStackTrace (); 8(ny^]v|  
} S<Q8kW:  
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return n; d|TRP,y  
} seY0"ym&e  
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} L
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/* 3Zg=ZnF  
**SiteInfoBean.java S;NC
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*/ WhE5u&`  
package NetFox; OzBo*X/p  
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<kn#`w1U'  
public class SiteInfoBean { LW_Y  
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private String sSiteURL; //Site's URL ^i&Qr+v  
private String sFilePath; //Saved File's Path )ZzwD]  
private String sFileName; //Saved File's Name ]]o7ej  
private int nSplitter; //Count of Splited Downloading File i051qpj  
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rsBF\(3b~  
public SiteInfoBean() e;x`C  
{//nSplitter的缺省值为5 5{#9b^  
//default value of nSplitter is 5 &k\
7fvF  
this("","","",5); z QoMHFL3  
} +;#hED;8  
. )Fn]x"<  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) QC~B8]  
{ SynxMUlA  
sSiteURL= sURL; l1jS2O(  
sFilePath = sPath; X X{:$f+  
sFileName = sName; 6`NsX  
this.nSplitter = nSpiltter; =N<Hc:<t4  
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} ;Iw'TF   
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8v1asFxs.  
public String getSSiteURL() ]gTaTY  
{ )_+"  
return sSiteURL; _kH#{4`Hw  
} la)f\Nk  
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public void setSSiteURL(String value) |:!#kA  
{ -iBu:WyY$  
sSiteURL = value; tt|U,o  
} AEPgQ9#E  
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public String getSFilePath() j /-p3#c  
{ )t&|oQ3sVG  
return sFilePath; C'n 9n!hR  
} N$Gx$u3Cd  
b_V)]>v+  
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public void setSFilePath(String value) PG<N\  
{ 7bsW7;C  
sFilePath = value; =6  
} HH^{,53%  
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public String getSFileName() Zu%_kpW  
{ &o4L;A#&  
return sFileName; _I{&5V~z  
} b%$S6.  
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A ,LAA$  
public void setSFileName(String value) C+5^[V  
{ @GnsW;$*~.  
sFileName = value; 8>pFpS  
} 42z9N\ f  
/unOZVr(
 
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public int getNSplitter() IZAbW  
{ GmAE!+"  
return nSplitter; apY m,_  
} Q7=J[,V:2  
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public void setNSplitter(int nCount) sE/9~L  
{ aOYd"S}u  
nSplitter = nCount;  }O1F.5I1  
} r`<evwIe  
} r.K4<ly-N  
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/* \re.KB#R  
**Utility.java RtqW!ZZ:H  
*/ *D<sk7  
package NetFox; }FM<uBKW  
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public class Utility { xVl90ak  
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public Utility() 3\(s=-vh  
{ ?: meix  
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k*!J,/=k  
} B=Zo0p^  
b7>;UX  
//线程睡眠 2>EIDRLJ-  
public static void sleep(int nSecond) ~NTpMF  
{ aD&10b9`  
try{ efbt\j6@%2  
Thread.sleep(nSecond); vG\Wr.h0!=  
} W_DO8nX  
catch(Exception e) v>nJy~O]  
{ 10[~ki-1;  
e.printStackTrace (); LXXxwIBS  
} p19Zxh  
}
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[ B (lJz  
//日志 ]a:kP,  
public static void log(String sMsg) a:;*"p[R  
{ Y7{|EI+@  
System.err.println(sMsg); pt0H*quwI  
} ol[{1KT{  
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5
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public static void log(int sMsg) 2l!"OiB.P  
{ *|=&MU*+  
System.err.println(sMsg); r?[mn^Bo5  
} tICxAp:  
} 6u.b?_u  
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be764do  
/* Eui;2P~  
**TestMethod.java 3p^WTQ>(  
*/ d&ZwVF!  
package NetFox; 4\$Ze0tv  
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$PTedJ}*Y  
public class TestMethod { 7H[+iS0  
)0GnTB;5Z  
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public TestMethod() tlcA\+%)  
{ ///xx/weblogic60b2_win.exe XsR%_eT  
try{ +2?0]6EQ  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); jOuv\$  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); m+u>%Ys`  
SiteFileFetch fileFetch = new SiteFileFetch(bean); )5&m:R9  
fileFetch.start(); sO  
} vj_oMmjKw  
catch(Exception e){e.printStackTrace ();} k|lxJ^V#  
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} &U,f~KJ  
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public static void main(String[] args) T.|0;Eb  
{ Q3/q%#q>  
new TestMethod(); 9M!_D?+P?  
} 57j:Lw~   
} ~/#?OLj(T  
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