http断点续传简单实现（java)

/* , R.+-X  
**SiteFileFetch.java UB&S 2
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*/ E!}-qbH^  
package NetFox; 7ck0S+N'b  
import java.io.*; 2p3u6\y  
import java.net.*; H8t{ >C)]  
!{]v='   
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public class SiteFileFetch extends Thread { Ji}IV  
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SiteInfoBean siteInfoBean = null; //文件信息Bean zIYr0k*%  
long[] nStartPos; //开始位置 (fGJP*YO  
long[] nEndPos; //结束位置 P=sK+}5`q  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 h&k^l,  
long nFileLength; //文件长度 .{]c&Ef+f  
boolean bFirst = true; //是否第一次取文件 0Li'a{n2  
boolean bStop = false; //停止标志 w7t"&=pF7  
File tmpFile; //文件下载的临时信息 )V$!  
DataOutputStream output; //输出到文件的输出流 #PLB$
$  
,md7.z]U~  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） kJ<Xq   
public SiteFileFetch(SiteInfoBean bean) throws IOException ! ?U^+)^$  
{ CTbhwY(/  
siteInfoBean = bean; p4t!T=o/  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); d$pf[DJQo  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 7E75s)KH  
if(tmpFile.exists ())
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{ p:Ld)U*  
bFirst = false; $:gSc&mx  
read_nPos(); SSsQu^A  
} !q6V@&  
else f({-j%m  
{ )Q  
nStartPos = new long[bean.getNSplitter()]; M Xt +  
nEndPos = new long[bean.getNSplitter()]; $?AUk  
} _:=OHURc  
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} M>H^<N}'A  
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public void run() er7/BE&  
{ }
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//获得文件长度 ]-Y]Q%A4  
//分割文件 E0B2>V  
//实例FileSplitterFetch HYYx*CJ)  
//启动FileSplitterFetch线程 Qbt>}?-  
//等待子线程返回 ^sn>p}T
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try{ ;3?J#e6;  
if(bFirst) V45Udwp^  
{ (kNTXhAr4  
nFileLength = getFileSize(); ABe^]HlH  
if(nFileLength == -1) 2#A9D.- h  
{ iGeT^!N  
System.err.println("File Length is not known!"); 7(USp#"  
} oS|~\,p"  
else if(nFileLength == -2) MG5Sn*(C  
{ iK:qPrk-  
System.err.println("File is not access!"); a;owG/\p  
} ^5 =E`q".  
else KY34 'Di  
{ P7.8tM2}  
for(int i=0;i<nStartPos.length;i++) w|FVqX  
{ ;Owu:}  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); qg:I+"u  
} Y~SlipY_  
for(int i=0;i<nEndPos.length-1;i++) n*4X/K  
{ B|$13dHfa  
nEndPos = nStartPos[i+1]; ,u^0V"hJ  
} i\4"FO?v  
nEndPos[nEndPos.length-1] = nFileLength; R9-JjG2v  
} @`8 B} C  
} ot<o&  
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//启动子线程 E0A|+P '?  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Vd>.fb\U2  
for(int i=0;i<nStartPos.length;i++) =&/a\z!  
{ GJ_)Cl+5E  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Vg~ kpgB
 
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Y"rV[oe  
nStartPos,nEndPos,i); FY}*Z=D%  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); J6Nw-qF  
fileSplitterFetch.start(); EI+/%.,  
} 9v,8OK)  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), mqT0^TNPcl  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1);  CF92AY
 
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", (KImqB$i.  
nEndPos = " + nFileLength); CWsv#XOg]  
// fileSplitterFetch[nPos.length-1].start(); n(xlad  
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//等待子线程结束 A1}+j-D7!y  
//int count = 0; ZDJWd
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//是否结束while循环 h`rjDd  
boolean breakWhile = false; 6="&K_Q7  
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f
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while(!bStop) }v,P3  
{ @W- f{V  
write_nPos(); W2Z]?l;vQQ  
Utility.sleep(500); ;rAW3  
breakWhile = true; c7!`d.{90  
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for(int i=0;i<nStartPos.length;i++) 0)a?W,+O  
{ k0Yixa  
if(!fileSplitterFetch.bDownOver) gt(nZ
  
{ 0-f-  
breakWhile = false; 6mpUk.M"  
break; >&Q. .`q  
} tKG
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} d'fpaLV  
if(breakWhile) _cN)q  
break; `
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//count++; f(o`=% k8  
//if(count>4) $_5v^QL  
// siteStop(); # |[@Due  
} }"H900WE|  
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System.err.println("文件下载结束！"); Bd[Gsns  
} wVtBeZa  
catch(Exception e){e.printStackTrace ();} N6%q%7F.:  
} x:lf=DlA  
&r!>2$B\  
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//获得文件长度 .6#2i <oPW  
public long getFileSize() _>64XUZ<n  
{ k]5L\]>y  
int nFileLength = -1; @$G K<jl  
try{ t}l<#X5  
URL url = new URL(siteInfoBean.getSSiteURL()); S-|$sV^cG  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); d^^>3L!h  
httpConnection.setRequestProperty("User-Agent","NetFox"); CZ}tQx5ga  
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int responseCode=httpConnection.getResponseCode(); epm|pA*  
if(responseCode>=400) y&]D2"I  
{ >UH=]$0N  
processErrorCode(responseCode); M -TK  
return -2; //-2 represent access is error P'k39  
} A79SAheX#  
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String sHeader; H
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for(int i=1;;i++) IYN`q'%|  
{ v)EJ|2`  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); j)Gr@F>  
//Utility.log(in.readLine()); K)ib{V(50  
sHeader=httpConnection.getHeaderFieldKey(i); (@9}FHJzi  
if(sHeader!=null) \g/E4U.+  
{ me" <+6  
if(sHeader.equals("Content-Length")) St<\qC  
{ /qG?(3  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); u05O[>w  
break; q~C6+  
} b-XBs7OAx  
} ~8K~@e$./  
else |kD?^Nx  
break; ?jnEHn  
} on|>"F`pb  
} ?##GY;#  
catch(IOException e){e.printStackTrace ();} $ a7
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catch(Exception e){e.printStackTrace ();} K\PS
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Utility.log(nFileLength); "]% L{aP  
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return nFileLength; 3.Qwn.  
} dc*#?G6^  
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$: -Ptm@  
//保存下载信息（文件指针位置） [@)|j=:i:  
private void write_nPos() R?k1)n   
{ Cv3H%g+as  
try{ =y ff.3mW\  
output = new DataOutputStream(new FileOutputStream(tmpFile)); %pdfGM9g  
output.writeInt(nStartPos.length); 4YJs4CB  
for(int i=0;i<nStartPos.length;i++) ;a|A1DmZ  
{ \AG,dMS  
// output.writeLong(nPos); 59LIK&w  
output.writeLong(fileSplitterFetch.nStartPos); y}|zH  
output.writeLong(fileSplitterFetch.nEndPos); 4V=dD<3m  
} [69aTl>/  
output.close(); =+u$ZZ0+]o  
} HV>Wf"1  
catch(IOException e){e.printStackTrace ();} k0,~wn\#h  
catch(Exception e){e.printStackTrace ();} _-^@Jx[
 
} +r '  
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//读取保存的下载信息（文件指针位置） ='f>p+*c%  
private void read_nPos() G$q=WM!%#s  
{ 5p750`n  
try{ ~ohW9Z1  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); m{' q(w}  
int nCount = input.readInt(); edch'H^2+P  
nStartPos = new long[nCount]; X|b~,X%N  
nEndPos = new long[nCount]; s%Z3Zj(,8(  
for(int i=0;i<nStartPos.length;i++) sUA)I%Q!  
{
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nStartPos = input.readLong(); dJ$}]   
nEndPos = input.readLong(); #fwG~Q(  
} [scPs,5Y  
input.close(); ,5nrovv  
} ^LZU><{';  
catch(IOException e){e.printStackTrace ();} _M7AQ5  
catch(Exception e){e.printStackTrace ();} [!v:fj  
} 4bmp
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private void processErrorCode(int nErrorCode) H>VuUH|  
{ >Z/,DIn,I
 
System.err.println("Error Code : " + nErrorCode); sLCL\dWT  
} {&3n{XrF(  
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//停止文件下载 CFVe0!\  
public void siteStop() ]NN9FM.2b/  
{ b"p,~{  
bStop = true; Z$T1nm%lo:  
for(int i=0;i<nStartPos.length;i++) z"R-Sme  
fileSplitterFetch.splitterStop(); Hl]3F^{  
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} C^.:{  
} UnGG%  
//负责部分文件的抓取 Cdc6<8  
**FileSplitterFetch.java TR]~r2z  
*/ ;g*ab
 
package NetFox; 9"oc.ue.2D  
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import java.io.*; R
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import java.net.*; m@)K]0g<f  
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public class FileSplitterFetch extends Thread { YX,y7Uhn  
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String sURL; //File URL ?$v#;n?@I  
long nStartPos; //File Snippet Start Position B$sB1M0q  
long nEndPos; //File Snippet End Position ggfL d r  
int nThreadID; //Thread's ID {!@Pho)Q  
boolean bDownOver = false; //Downing is over XX#YiG4|J  
boolean bStop = false; //Stop identical 1 f).J  
FileAccessI fileAccessI = null; //File Access interface x<4-Q6'{S  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException W/OZ}ky}^  
{ }>>lgW>n,;  
this.sURL = sURL; e}D#vPaSY  
this.nStartPos = nStart; aHvTbpJ  
this.nEndPos = nEnd; g`k_o<'JC  
nThreadID = id; ;JFy 8Rj  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 +h.$<=  
} G$<FQDvs  
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public void run() 9K-=2hvv  
{ ppP7jiGo  
while(nStartPos < nEndPos && !bStop) J*IC&jH:  
{ )<nr;n  
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try{  [R:\  
URL url = new URL(sURL); Q{F*
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); i'aV=E5  
httpConnection.setRequestProperty("User-Agent","NetFox"); /X>Fn9mM  
String sProperty = "bytes="+nStartPos+"-"; ('BFy>@  
httpConnection.setRequestProperty("RANGE",sProperty); L8sHG$[  
Utility.log(sProperty); (lBgW
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# Un>g4>Rh  
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InputStream input = httpConnection.getInputStream(); 'S]7:/CI  
//logResponseHead(httpConnection); +c$]Q-(  
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}#va#Nb(,  
byte[] b = new byte[1024]; ~7a(KJgvd"  
int nRead; xLhN3#^m  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) PEqO<a1Z8  
{ +s?0yH-%p  
nStartPos += fileAccessI.write(b,0,nRead); m!{Xuy  
//if(nThreadID == 1) r:Uqtqxh  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); R+,eXjz"  
} owHV&(Go(B  
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Utility.log("Thread " + nThreadID + " is over!"); baJ(Iy$XT  
bDownOver = true; ;o*n*N  
//nPos = fileAccessI.write (b,0,nRead); AfAg#75q  
} ZuF"GNUC  
catch(Exception e){e.printStackTrace ();} >b9nc\~  
} 4JF)w;X}  
} sDNV_
} h  
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//打印回应的头信息 =fk+"!-i%"  
public void logResponseHead(HttpURLConnection con) R1$O)A}k  
{ f44b=,Lry5  
for(int i=1;;i++) hF`e>?bN  
{ pe(31%(h  
String header=con.getHeaderFieldKey(i); Th1/Bxb:  
if(header!=null) 7)iB6RBK  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); N$#518  
Utility.log(header+" : "+con.getHeaderField(header)); Ut"~I)S{LT  
else z@@w?>*  
break; 8Q $fXB  
} 8&?kr/_Vr  
} QEd>T"@g  
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public void splitterStop() _3_d;j#G U  
{ gcLwQ-  
bStop = true; a`SQcNBf*  
} kaSi sjd  
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} 3@u<
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/* |Ld/{&Qr  
**FileAccess.java ?_
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*//文件访问(定位，写)
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package NetFox; F_8< tA6  
import java.io.*; w h4WII  
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public class FileAccessI implements Serializable{ V*an0@  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节
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RandomAccessFile oSavedFile; zj G>=2  
long nPos; 4[@`j{  
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public FileAccessI() throws IOException lWYZAF>?Ym  
{ [3Qu @;"&  
this("",0); Z1V%pg>]*  
} 9C-!I,  
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public FileAccessI(String sName,long nPos) throws IOException EH;w <LvT  
{ ,^dyS]!d$  
oSavedFile = new RandomAccessFile(sName,"rw"); l.tNq$3pS  
this.nPos = nPos; }=kf52Am,}  
oSavedFile.seek(nPos); D@[Mk
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} =F>@z4[P-  
f< A@D"m/  
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public synchronized int write(byte[] b,int nStart,int nLen) z"`q-R }m  
{ wKe$(>d"L  
int n = -1; &_Py{Cv@Dw  
try{ XY(3!>/eQ[  
oSavedFile.write(b,nStart,nLen); 3q*y~5&I  
n = nLen; ]ZkhQ%  
} E\U6n""]  
catch(IOException e) Vc!` BiH  
{ AF5$U
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e.printStackTrace (); y=!"++T]B<  
} ]<z4p'F1%  
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return n; $+` YP  
} 5@3[t`n'  
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} }wmn v  
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/* g|*2O}<  
**SiteInfoBean.java xZjl_bJ  
*/ Q\G8R^9j p  
package NetFox; rDkAeX0  
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public class SiteInfoBean { $
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private String sSiteURL; //Site's URL ($*bwqp]}  
private String sFilePath; //Saved File's Path cSCO7L2E18  
private String sFileName; //Saved File's Name E",s]  
private int nSplitter; //Count of Splited Downloading File RWmQP%A}aw  
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21GjRPs\  
public SiteInfoBean() ) Ph.  
{//nSplitter的缺省值为5 9Ue3
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//default value of nSplitter is 5 uyP)5,  
this("","","",5); ^7v}wpwX\  
} /b,+YyWi%  
vC~];!^  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) L>$yslH;b  
{ P(G$@},W  
sSiteURL= sURL; L*bUjR,C  
sFilePath = sPath; |Hg)!5EJ  
sFileName = sName; (V@g?|LZ  
this.nSplitter = nSpiltter; {EbR =  
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} 6XUcJ0  
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public String getSSiteURL() .6SdSB^M  
{ w[\*\'Vm0  
return sSiteURL; XyJ*>;q  
} G_zJuE$V  
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public void setSSiteURL(String value) s`xp6\$  
{ Gm^@lWzG  
sSiteURL = value; '#xxjhF^  
} `x$d8(1J`#  
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public String getSFilePath() r&)/3^S '  
{ 0!veLXeK!  
return sFilePath; +`9 ]L]J]4  
} q7mqzMDk  
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public void setSFilePath(String value) 3 8pw  
{ rZ 9bz}K  
sFilePath = value; }$#e&&)n  
} nH}api^0A  
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public String getSFileName() l"o@.C}f/  
{ W+BM|'%}|  
return sFileName; 'VFxg,  
} ma@ws,H  
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public void setSFileName(String value) y/mxdPw  
{ Ks@S5:9sp  
sFileName = value; y;Q_8|,F  
} LdR}v%EH  
I!9u](\0  
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public int getNSplitter() $EW31R5h<s  
{ '@2pOq  
return nSplitter; ,& =(DJ  
} Sd' uXX@  
u91;GBY  
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public void setNSplitter(int nCount) wfM$JYfI  
{ ] M"{=z  
nSplitter = nCount; K8Gc5#OF  
} ,Bp\ i  
} !cE>L~cza  
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/* v~q2D"  
**Utility.java t9&)9,my  
*/ Nz#T)MGO`  
package NetFox; c 6}d{B[  
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public class Utility { mC n,I  
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public Utility() &BqRyUM$F  
{  IKKd  
qCSJ=T
;  
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} 7]d396%  
9'o!9_j  
//线程睡眠 T.<eriv  
public static void sleep(int nSecond) -_ .f&l8  
{ l]W
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try{ .UakO,"z  
Thread.sleep(nSecond); 
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} ,]i ^/fT  
catch(Exception e) N)lzX X  
{ |rH;}t|un  
e.printStackTrace (); 4wX{N   
} _Hl[Fit<j1  
} Z_}vjk~s  
R5ZnkPEA  
//日志 r*N:-I~z  
public static void log(String sMsg) M-K<w(,X
 
{ Vg#s  
System.err.println(sMsg); [
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} 5UVQ48aT  
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A,
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public static void log(int sMsg) CCDoiTu!4  
{ l:a+o gm3  
System.err.println(sMsg); 9hHQWv7TgK  
} a^<  
} {W3%n*q  
0L$v7
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wp-5B= #:{  
/* TgSU}Mf)a  
**TestMethod.java o*:VG\#Z6  
*/ .6!IO^`[  
package NetFox; j2cLb  
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public class TestMethod { O_nk8  
5@tpJ8E8$  
! W$u~z  
public TestMethod() @CP"AYB #  
{ ///xx/weblogic60b2_win.exe V2ypmkn8&  
try{ >@[`,  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); %/,PY>:|  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 'd]9u9u  
SiteFileFetch fileFetch = new SiteFileFetch(bean); kWF4k  
fileFetch.start(); q#pBlJ.LK  
} q =b.!AZy  
catch(Exception e){e.printStackTrace ();} b\7-u-   
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} { Y|h;@j$  
#-'=)l}i1A  
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public static void main(String[] args) A]Zp1XEG  
{ h.%VWsAO7  
new TestMethod(); W([)b[-*  
} <.HHV91  
} yH|ucN~k5S  
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