http断点续传简单实现（java)

/* 8pf]M&  
**SiteFileFetch.java NRG06M  
*/ $Tv~ *|a  
package NetFox; ,d*1|oUw  
import java.io.*; A",}Ikh='`  
import java.net.*; oj.J;[-  
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public class SiteFileFetch extends Thread { ae-tAA[1Y  
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SiteInfoBean siteInfoBean = null; //文件信息Bean EdqB4-#7  
long[] nStartPos; //开始位置 _t"[p_llo  
long[] nEndPos; //结束位置 g||EjCsp  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 6:S, {@G  
long nFileLength; //文件长度 
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boolean bFirst = true; //是否第一次取文件 i._RMl5zg  
boolean bStop = false; //停止标志 Fs~*-R$  
File tmpFile; //文件下载的临时信息 x>mI$K(6M  
DataOutputStream output; //输出到文件的输出流 wQhuU  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） g]JJ!$*1  
public SiteFileFetch(SiteInfoBean bean) throws IOException Z" H;t\P  
{ *tT}N@<%  
siteInfoBean = bean; PA803R74  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); .7 )oWd!  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); SIm1fC  
if(tmpFile.exists ()) qZE3T:S  
{ A@_>9;   
bFirst = false; ~9APc{"A  
read_nPos(); R}w}G6"\  
} z &P1C,n)  
else 5m'AT]5Tn_  
{ d3\?:}o,  
nStartPos = new long[bean.getNSplitter()]; %^E7Iqc  
nEndPos = new long[bean.getNSplitter()]; _(?`eWo  
} K_ymA,&()  
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} j&/+/s9N  
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public void run() OO?N)I
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{ :4
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//获得文件长度 &`s{-<t<L  
//分割文件 :qqG%RB  
//实例FileSplitterFetch nu+^D$ait  
//启动FileSplitterFetch线程 3rFku"zT$  
//等待子线程返回 |xZu?)M4  
try{ `peR,E  
if(bFirst) " wT?$E  
{ xv2c8g~vD  
nFileLength = getFileSize(); ^/}4M'[w  
if(nFileLength == -1) cy(w*5Upu  
{ {T^D&i# o  
System.err.println("File Length is not known!"); KyT=:f V  
} Q5dqn"?  
else if(nFileLength == -2) P-[})Z=  
{ !pRu?5  
System.err.println("File is not access!"); ?[bE/Ya+S  
} 2V%z=  
else kl~/tbf
 
{ yU/?4/G!  
for(int i=0;i<nStartPos.length;i++) 9 4H')(  
{ t\QLj&h}E  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); $X-PjQb1Bb  
} &R.5t/x_  
for(int i=0;i<nEndPos.length-1;i++) <Qv/# k  
{ \reVA$M[  
nEndPos = nStartPos[i+1]; tboQn~&4  
} '{~[e**  
nEndPos[nEndPos.length-1] = nFileLength;  WvF{`N  
} `Rq|*:LV  
} Q_fgpjEh/t  
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PHT<]:"`<  
//启动子线程 'l!\2Wv2  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; l,Y5VGiH#  
for(int i=0;i<nStartPos.length;i++) Wk3-J&QbS  
{ 2brY\c
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fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), r{d@74  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), CeOA_M  
nStartPos,nEndPos,i); Go:(R {P  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); !nJl.Y$  
fileSplitterFetch.start(); am3JzH  
} #E=8kbD7  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), i" u|119  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); i Pr(X  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", VfJ{);   
nEndPos = " + nFileLength); A9SL|9Q  
// fileSplitterFetch[nPos.length-1].start(); n2-+.9cY  
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//等待子线程结束 2+)h!y]  
//int count = 0; mh[,E8'd  
//是否结束while循环 `{K-eHlrM9  
boolean breakWhile = false; b@4UR<  
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while(!bStop) =ZU!i0 K  
{ W\Scak>  
write_nPos(); a]P%Y.?r  
Utility.sleep(500); <4;, y*"n  
breakWhile = true; bp?TO]LH  
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[R8BcO(  
for(int i=0;i<nStartPos.length;i++) r9bAbE bI  
{ C_ d|2C6  
if(!fileSplitterFetch.bDownOver) aw lq/
 
{ 52# *{q}  
breakWhile = false; ND?
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break; E]&N'+T
 
} %nq<nfDT  
} 2P'Vp7f6 Y  
if(breakWhile) :+QNN<  
break; .j,xh )v"  
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$
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//count++; tAep_GR  
//if(count>4) T>1#SWQ/9  
// siteStop(); @V^.eVM\R  
} $U7/w?gc'  
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System.err.println("文件下载结束！"); P%yL{  
} kzUj)  
catch(Exception e){e.printStackTrace ();} Oz_CEMcy  
} 3;}YW^oXq  
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//获得文件长度 p}!)4EI=  
public long getFileSize() 5z3WRg
 
{ IRk)u`  
int nFileLength = -1; j?$B@Zk  
try{ rDwd!Jet  
URL url = new URL(siteInfoBean.getSSiteURL()); [{xY3WS  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 6.45^'t]  
httpConnection.setRequestProperty("User-Agent","NetFox"); <
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int responseCode=httpConnection.getResponseCode(); AriV4 +  
if(responseCode>=400) Citumc)E  
{ IN1n^f$:  
processErrorCode(responseCode); #2Q%sE?  
return -2; //-2 represent access is error %j17QD8  
} |SMigSu r`  
#>_fYj
T  
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String sHeader; hF^JSCDz l  
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for(int i=1;;i++) B$JPE7h@[P  
{ 9dszn^]T  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); mqJD+ K  
//Utility.log(in.readLine()); `'r]Oe  
sHeader=httpConnection.getHeaderFieldKey(i); '#j6ZC/?  
if(sHeader!=null) KdHkX+-R  
{ }>y~P~`S:  
if(sHeader.equals("Content-Length")) !(Y|Vm'  
{ n 78!]O  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ]moBVRd  
break; p\'X%R  
} Mx93D   
} dXY}B=C  
else P*?2+.  
break; r SoT]6/   
} }/NjZ*u  
} p.4Sgeh#  
catch(IOException e){e.printStackTrace ();} ^HP$r*  
catch(Exception e){e.printStackTrace ();} MGwXZ7?E  
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Utility.log(nFileLength); *Y53bZ  
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return nFileLength; q(s0dkrj  
} {t0!N]'  
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//保存下载信息（文件指针位置） T72Z<h|<  
private void write_nPos() Avljrds+7  
{ zKYN5|17  
try{ 5>1c4u`x  
output = new DataOutputStream(new FileOutputStream(tmpFile)); F)'_,.?0  
output.writeInt(nStartPos.length); Bgsi$2hI  
for(int i=0;i<nStartPos.length;i++) }L{GwiDMDl  
{ =.m/X>  
// output.writeLong(nPos); srImk6YD  
output.writeLong(fileSplitterFetch.nStartPos); #z_.!E  
output.writeLong(fileSplitterFetch.nEndPos); bccf4EyQ Y  
}  UiK)m:NU  
output.close(); 8r,0Qic2K  
} T|YMU?4  
catch(IOException e){e.printStackTrace ();} Z>1yLt@ls  
catch(Exception e){e.printStackTrace ();} [["eK9}0  
} ]4*E:  
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//读取保存的下载信息（文件指针位置） 4uE/!dT  
private void read_nPos() >K%+h)%kI  
{ 4 l+z  
try{ V%M@zd?u.  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Iz#jR2:yn  
int nCount = input.readInt(); JGzEm>_m  
nStartPos = new long[nCount]; 0H'G./8
  
nEndPos = new long[nCount]; !14v Ovj4{  
for(int i=0;i<nStartPos.length;i++) cZ.p  
{ @v/Ae_q!  
nStartPos = input.readLong(); &;vMJ   
nEndPos = input.readLong(); )T(1oK(g  
} 3ox|Mz<aZX  
input.close(); h:z$uG  
} daQJ{Cd,w  
catch(IOException e){e.printStackTrace ();} dt<P6pK-  
catch(Exception e){e.printStackTrace ();} &)!N5Veb  
} `v/p4/  
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private void processErrorCode(int nErrorCode) e<u~v0r
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{ Fb{HiU9<!  
System.err.println("Error Code : " + nErrorCode); 1[RI 07g7*  
} vBY?3p,0p  
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//停止文件下载 _w5c-\-PUM  
public void siteStop() ;t.)A3 PL  
{ te>Op 1R  
bStop = true; x+Ly,9nc$  
for(int i=0;i<nStartPos.length;i++) RtaMrG=D  
fileSplitterFetch.splitterStop(); \:Hh'-77q  
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} [|YuT:Cp  
} (I1^nrDP.  
//负责部分文件的抓取 h)r=+Q\'(S  
**FileSplitterFetch.java QT"o"B  
*/ .36]>8  
package NetFox; Ob|tA  
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import java.io.*; [XA:pj;rg'  
import java.net.*; vcOw`oS  
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public class FileSplitterFetch extends Thread { |Yi_|']#  
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String sURL; //File URL +5Y;JL<%/  
long nStartPos; //File Snippet Start Position >+[{m<Eq  
long nEndPos; //File Snippet End Position g
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int nThreadID; //Thread's ID $cO-+Mr-~  
boolean bDownOver = false; //Downing is over Gx%f&H~Z^  
boolean bStop = false; //Stop identical ch/DBu  
FileAccessI fileAccessI = null; //File Access interface 5*y6{7FLp  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException <
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{ v +?'/Q%  
this.sURL = sURL; gp^xl>E  
this.nStartPos = nStart; )Y=ti~?M(  
this.nEndPos = nEnd; }A<fCm7  
nThreadID = id;  7"])Y  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 G/_8xmsU  
} ]rO/I
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public void run() 1L_(n  
{ h7}P5z0F  
while(nStartPos < nEndPos && !bStop) ;'4Kg@/  
{ }~ga86:n0  
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try{ |f[:mO
  
URL url = new URL(sURL); U;U19[]  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 7I:<i$)V  
httpConnection.setRequestProperty("User-Agent","NetFox"); "
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String sProperty = "bytes="+nStartPos+"-"; DPlmrN9@=  
httpConnection.setRequestProperty("RANGE",sProperty); XiyL563gh  
Utility.log(sProperty); ,LDdL  
#4^D'r>pJ  
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InputStream input = httpConnection.getInputStream(); *iVv(xXgN  
//logResponseHead(httpConnection); <TEDs4 C  
8H{9  
8-Z|$F"  
byte[] b = new byte[1024]; 0(|36;x  
int nRead; )KN]"<jB  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) h]
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{ =#?=Lh  
nStartPos += fileAccessI.write(b,0,nRead); E@)9'?q  
//if(nThreadID == 1) ]7%+SH,RdD  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); TmgSV#G  
} EvDg{M}  
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BbNl:`  
Utility.log("Thread " + nThreadID + " is over!"); 1lHBg  
bDownOver = true; t[bZg9;  
//nPos = fileAccessI.write (b,0,nRead); V_H0z  
} frbeCBP&)  
catch(Exception e){e.printStackTrace ();} k{+Gv}Y  
} m^1'aO_;q  
} 9Qc=D
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//打印回应的头信息 q>dERN&  
public void logResponseHead(HttpURLConnection con) I- WR6s=  
{ x1 1ug  
for(int i=1;;i++) !MD uj  
{ 
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String header=con.getHeaderFieldKey(i); PA${<wyBR_  
if(header!=null) +C`zI~8  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); R"{oj]d;$F  
Utility.log(header+" : "+con.getHeaderField(header)); ,) 3Eog\-  
else 0d #jiG  
break; EceD\}  
} A@ 4Oq  
} Qr*7bE(a  
+bc
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public void splitterStop() Ku]<$uo  
{ 95BRZ!ts  
bStop = true; xayd_RB9  
} :@sjOY  
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} N5@l[F7I  
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/* =_9grF-  
**FileAccess.java N/
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*//文件访问(定位，写) z%[^-l-  
package NetFox; 5^GrG|~  
import java.io.*; qM0Df0$?x  
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public class FileAccessI implements Serializable{ HmVp
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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 oD
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RandomAccessFile oSavedFile; _[ufH*  
long nPos; >$N ?\\#  
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?wbf)fbq  
public FileAccessI() throws IOException WxF0LhM  
{ bWfT-Jewh  
this("",0); 35fsr=  
} Uk=L?t  
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public FileAccessI(String sName,long nPos) throws IOException C!S(!Z,  
{ Tyt1a>!qA  
oSavedFile = new RandomAccessFile(sName,"rw"); JAP4Vwj%j  
this.nPos = nPos; s<fzk1LZ  
oSavedFile.seek(nPos); n*vhCeL  
} Ox}a\B8  
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SW*Yu{  
public synchronized int write(byte[] b,int nStart,int nLen) }Jk=ZBVjT7  
{ {N 0i 3e s  
int n = -1; Vh5Z'4N  
try{ 2f7]=snCG  
oSavedFile.write(b,nStart,nLen); zUd{9B$  
n = nLen; f|-%.,  
} uUI@!)@2  
catch(IOException e) PvqG5-L~W  
{ " )/febBS  
e.printStackTrace (); Y8%*S%yO  
} 0N4+6k|  
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return n; @DA.$zn&  
} >p@v'h/Cr  
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} c:sk1I,d~^  
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@6:J$B~)u  
/* ,)7y?*D}  
**SiteInfoBean.java a) 5;Od  
*/ Vo:Gp  
package NetFox; =hDFpb,mr  
m #}%l3$  
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public class SiteInfoBean { rk .tLk  
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private String sSiteURL; //Site's URL ;$$.L bb8  
private String sFilePath; //Saved File's Path 9a lMC  
private String sFileName; //Saved File's Name ;ZowC#j  
private int nSplitter; //Count of Splited Downloading File f<v:
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public SiteInfoBean() a>XlkkX  
{//nSplitter的缺省值为5 T9=55tpG9  
//default value of nSplitter is 5 m*Q*{M_e  
this("","","",5); bf1EMai"  
} "fX9bh^  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter)
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{ <m!(eLm+B  
sSiteURL= sURL; 47 *,  
sFilePath = sPath; {m
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sFileName = sName; mDJ
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this.nSplitter = nSpiltter; Xj("  
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} FF7  
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!<I3^q  
public String getSSiteURL() S@PAtB5  
{ t;e+WZkV  
return sSiteURL; T.kQ] h2ZG  
} 6e.?L  
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public void setSSiteURL(String value) Y] "_}  
{ ZAcH`r*  
sSiteURL = value; @ATJ|5.gr  
} )`B n"=  
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public String getSFilePath() _yJAn\  
{ R#0Z  
return sFilePath; b9gezXAcd  
} H^N 5yOj/  
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public void setSFilePath(String value) EA+}Rf6}  
{ slWO\AYiO  
sFilePath = value; tjIT4  
} Yf=Puy}q  
3Sb'){.MT+  
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public String getSFileName() //_aIp  
{ h<8.0  
return sFileName; cXY;Tw45  
} mqFo`Ee  
c Oi:bC@  
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public void setSFileName(String value) ,J63?EQ3  
{ vOl<  
sFileName = value; ~p0M|  
} bm:"&U*tu'  
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public int getNSplitter() '**dD2 n  
{ .3QX*]{  
return nSplitter; QFS5P
Z  
} Ja@zeD)f"  
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public void setNSplitter(int nCount) E"l/r4*f@  
{ Xi~%,~  
nSplitter = nCount; 2l#c?]TA  
} YAoGVey  
} f,_EPh>  

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/* ZFNn
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**Utility.java &rmXz6F  
*/ l9eCsVQ~V  
package NetFox; dvl'Sq<  
g} /efE  
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public class Utility { -~'{WSJ  
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public Utility() +=Q/'g   
{ |\W9$V  
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1  
} +%%Ef]  
}+{? Ms  
//线程睡眠 } qf=5v  
public static void sleep(int nSecond) f=L&>X  
{ Q*J8`J:#^R  
try{ ~5Cid)Q}@o  
Thread.sleep(nSecond); &Is}<Ew  
} &*4C{N  
catch(Exception e) nbECEQ:|B  
{ dpPu&m+  
e.printStackTrace (); ZHWxU  
} PqJB&:ZV  
} yDil  
d}Y\;'2,  
//日志 'Cv>V"X: `  
public static void log(String sMsg) Uf ?._&:  
{ &I|\AG"X}  
System.err.println(sMsg); \pVmSac,  
} z{N~AaY  
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,L.*95,  
public static void log(int sMsg) @> ]O6P2  
{ ;;zQVD )X  
System.err.println(sMsg); Pd"=&Az|  
} z3bRV{{YqN  
} nN]G
O}  
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w I7iE4\vz  
/*
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**TestMethod.java NZTG)<  
*/ UCz\SZ{za  
package NetFox; }^@Q9<P^E  
iaAj|:  
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public class TestMethod { 5x=aJl;G  
@5rl;C  
s IE2a0+  
public TestMethod() ^]cl:m=*  
{ ///xx/weblogic60b2_win.exe =,])xzG%  
try{ T{"[Ih3Mbl  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); %lbDcEsf9  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); A%[BCY_  
SiteFileFetch fileFetch = new SiteFileFetch(bean); s.#%hPX{  
fileFetch.start(); JdK'~-L  
} pXy'Ss@y  
catch(Exception e){e.printStackTrace ();} U{JD\G8m  
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~v$1@DQ}  
} Y_gMoo  
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public static void main(String[] args) w!j'k|b>  
{ sMn)[k vX  
new TestMethod(); AVnH|31dC~  
} j TyR+#Wn  
} ?^Q8#Y^M  
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