http断点续传简单实现（java)

/* @7j AL-  
**SiteFileFetch.java P! #[mio  
*/ T <ET )
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package NetFox; Q|?L*Pq2I  
import java.io.*; Y^EcQzLw  
import java.net.*; s{\8om'-  
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public class SiteFileFetch extends Thread { 0*D$R`$  
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SiteInfoBean siteInfoBean = null; //文件信息Bean "8jf81V*  
long[] nStartPos; //开始位置 fN^8{w/O  
long[] nEndPos; //结束位置 ]{m
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FileSplitterFetch[] fileSplitterFetch; //子线程对象 9c,'k#k  
long nFileLength; //文件长度 dufu|BL|}  
boolean bFirst = true; //是否第一次取文件 1+{{EOZ4  
boolean bStop = false; //停止标志 9} M?
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File tmpFile; //文件下载的临时信息 .Una+Z  
DataOutputStream output; //输出到文件的输出流 X296tA>C`  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） a:IC)]j$_  
public SiteFileFetch(SiteInfoBean bean) throws IOException EF}\brD1  
{ nIy}#MUd|q  
siteInfoBean = bean; Y}|X|!0x  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); vJc-6EO
 
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 'RYIW/a  
if(tmpFile.exists ()) `
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{ rkCx{pe9  
bFirst = false; ]e>w}L(gV  
read_nPos(); >kDQkhZ  
} dkBIx$t  
else 1.{z3_S21:  
{ {|_M #w~&  
nStartPos = new long[bean.getNSplitter()]; *>'V1b4}  
nEndPos = new long[bean.getNSplitter()]; Yz"#^j}Kg  
} })8N5C+KU  
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} GmEJhr.3`=  
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public void run() JZ*/,|1}EC  
{ BmMGx8P  
//获得文件长度 6x[}g  
//分割文件 A_ N;   
//实例FileSplitterFetch ZC`wO%,  
//启动FileSplitterFetch线程 %wvdn  
//等待子线程返回 yyRiP|hJ  
try{ '(yAfL 9}  
if(bFirst) a#y;d
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{ 5Y'qaIFR  
nFileLength = getFileSize(); lVR~Bh  
if(nFileLength == -1) ?2;&O`x*  
{ *
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System.err.println("File Length is not known!"); R_ ,UMt  
} K'Tm_"[u  
else if(nFileLength == -2) eH3JyzzP,  
{ x?p1 HUK  
System.err.println("File is not access!"); [.'|_l  
} +]A:M6P:{v  
else Ym{tR,g7  
{ \y)rt )  
for(int i=0;i<nStartPos.length;i++) zRl3KjET  
{ k_q
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); N^ds RYC  
} H*QIB_  
for(int i=0;i<nEndPos.length-1;i++) #ASz;$P  
{ )}]g] g  
nEndPos = nStartPos[i+1]; *1 ]uH e  
} WJndoB.f[2  
nEndPos[nEndPos.length-1] = nFileLength; nntuLuW  
} BNl5!X^{  
}
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//启动子线程 \H~T>j{N  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; t#/YN.@r  
for(int i=0;i<nStartPos.length;i++) VT%NO'0  
{  &)Tdc  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), }bpQq6ZF  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), vNY{j7l/W  
nStartPos,nEndPos,i); Gg3,:A_ w  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); C'@i/+  
fileSplitterFetch.start(); E7Ul;d  
} @=Uh',F  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), s1$nvTzBr  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); }b"yU#`Q\  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", +I:Unp  
nEndPos = " + nFileLength); cAqLE\h  
// fileSplitterFetch[nPos.length-1].start(); (KD RkE|=  
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//等待子线程结束 |`,2ri*5A  
//int count = 0; |=ba9&q  
//是否结束while循环 ufZDF=$
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boolean breakWhile = false; 7P5)Z-K[  
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while(!bStop) Ugt/rf5n  
{ gNrjo=  
write_nPos(); [{,T.;'<j  
Utility.sleep(500); Apag{Z]^B  
breakWhile = true; L>NL:68yN  
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for(int i=0;i<nStartPos.length;i++) 5iw<>9X*  
{ fLD,5SN  
if(!fileSplitterFetch.bDownOver) ~i{(<.he  
{ >d*@_kJM  
breakWhile = false; !bx;Ta.  
break; e8!5I,I  
} 8oseYH  
} ")5":V~fN  
if(breakWhile) Al^d$FaF  
break; J26VnK  
{n.PF8A5X  
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//count++; 9Cp-qA%t  
//if(count>4) )5JFfp)#  
// siteStop(); |?xN\O^#}  
} EIAc@$4  
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System.err.println("文件下载结束！"); beGa#JH,  
} Rz/
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catch(Exception e){e.printStackTrace ();} P[ck84F/  
} *?>T,gx}  
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//获得文件长度 TnA-;Ha  
public long getFileSize() J#(LlCs?@c  
{ D& i94\vVa  
int nFileLength = -1; }W8;=$jr  
try{ |O+H[;TB6  
URL url = new URL(siteInfoBean.getSSiteURL()); >J?fl8  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); D|p9qe5%  
httpConnection.setRequestProperty("User-Agent","NetFox"); qkY:3O
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int responseCode=httpConnection.getResponseCode(); ~<5!?6Yt  
if(responseCode>=400) yYYSeH  
{ @ioJ]$o7  
processErrorCode(responseCode); NB#OCH1/9  
return -2; //-2 represent access is error g2ixx+`?|:  
} wo/\]5  
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String sHeader; N!=v4f  
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for(int i=1;;i++) iy!=6  
{ n'LrQU  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Uz8
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//Utility.log(in.readLine()); #A/  
sHeader=httpConnection.getHeaderFieldKey(i); Rsk4L0  
if(sHeader!=null) $GcqBg-Hi  
{ ]p GL`ge5  
if(sHeader.equals("Content-Length")) q`7PhA
  
{ :\c ^*K(9  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ie95rZp  
break; a#k6&3m&  
} P|E| $)m  
} rJ4S%6w  
else FVbb2Y?R  
break; f~R(D0@  
} R+z2}}Z!`  
} Y\P8v  
catch(IOException e){e.printStackTrace ();} #p&qUw  
catch(Exception e){e.printStackTrace ();} 7Q9 w?y~c  
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Utility.log(nFileLength); ?e4YGOe.  
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return nFileLength; ,w4(kcg%iQ  
} : *#-%0  
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//保存下载信息（文件指针位置） AV]2euyn  
private void write_nPos() my1@41 H  
{ JyK3{wYS  
try{ 3;9^  
output = new DataOutputStream(new FileOutputStream(tmpFile)); WE#^a6  
output.writeInt(nStartPos.length); V2EUW!gn 2  
for(int i=0;i<nStartPos.length;i++) f'RX6$}\1X  
{ R) h#Vc(  
// output.writeLong(nPos); 'JE`(xD  
output.writeLong(fileSplitterFetch.nStartPos); };zFJ6I8  
output.writeLong(fileSplitterFetch.nEndPos); _;
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} Gb6'n$g  
output.close(); d7y[0<xM  
} Bkc4TO  
catch(IOException e){e.printStackTrace ();} >Cp0.A:UC#  
catch(Exception e){e.printStackTrace ();} uH^-R_tQ  
}  8dA~\a  
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//读取保存的下载信息（文件指针位置） (5YM?QAd  
private void read_nPos() vA{-{Q  
{ F/{!tx  
try{ T'9'G M  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Sz`,X0a  
int nCount = input.readInt(); RtS+<^2a;  
nStartPos = new long[nCount]; ? OM!+O  
nEndPos = new long[nCount]; 1CZgb  
for(int i=0;i<nStartPos.length;i++) \gaw6S>n}  
{ Wn2NMXK  
nStartPos = input.readLong(); ^^$s%{ep"  
nEndPos = input.readLong(); IEi^kJflU  
} U7F!Z( 9  
input.close(); 90rol~M&  
} =UQ3HQD  
catch(IOException e){e.printStackTrace ();} T!#GW/?  
catch(Exception e){e.printStackTrace ();} CAhXQ7w'Z  
} r l%  
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private void processErrorCode(int nErrorCode) $s:aW^k  
{ \M^bD4';>  
System.err.println("Error Code : " + nErrorCode); Qw*|qGvy^  
} C&%_a~  
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CHX#^0m.  
//停止文件下载 Wac&b  
public void siteStop() XpHrt XD  
{ va@Lz&sAE%  
bStop = true; wP@(?z  
for(int i=0;i<nStartPos.length;i++) kTgEd]^&D  
fileSplitterFetch.splitterStop(); gwMNYMI  
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} ;A*]l'[-  
} oMa6(3T?E  
//负责部分文件的抓取 I\ob7X'Xu!  
**FileSplitterFetch.java lymCH  
*/ NXrlk  
package NetFox; W${Ue#w77  
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import java.io.*; :"c*s4  
import java.net.*; TvbE2Q;/UL  
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public class FileSplitterFetch extends Thread { )y$(AJx$  
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String sURL; //File URL li.;IWb0+)  
long nStartPos; //File Snippet Start Position " H\k`.j  
long nEndPos; //File Snippet End Position UCjld  
int nThreadID; //Thread's ID X \/#@T  
boolean bDownOver = false; //Downing is over NBGH_6DROw  
boolean bStop = false; //Stop identical kuP(r  
FileAccessI fileAccessI = null; //File Access interface sXPe/fWo  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException |CyE5i0  
{ 5$k:t  
this.sURL = sURL; [4f{w%~^  
this.nStartPos = nStart; j\M?~=*w  
this.nEndPos = nEnd; ?=Kduef  
nThreadID = id; > ~O.@|  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Gd85kY@w7  
} JWxwJex  
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public void run() @q)d  
{ lThB2/tV\  
while(nStartPos < nEndPos && !bStop) [7y]n;Fy  
{ 8":Q)9;%  
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try{ WpvhTX  
URL url = new URL(sURL); %pCT
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); es7=%!0  
httpConnection.setRequestProperty("User-Agent","NetFox"); &oMh]Z*:  
String sProperty = "bytes="+nStartPos+"-"; "w<#^d_6  
httpConnection.setRequestProperty("RANGE",sProperty); kAUymds;O  
Utility.log(sProperty); f!X[c?Xy"  
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InputStream input = httpConnection.getInputStream(); p!%pP}I  
//logResponseHead(httpConnection); OjA,]Gv6  
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byte[] b = new byte[1024]; C3g_!dUs  
int nRead; VIf.q)_k  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ;O,jUiQ  
{ qHsA1<wg  
nStartPos += fileAccessI.write(b,0,nRead); N;%6:I./  
//if(nThreadID == 1) f$QNg0v  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); v3>UV8c'  
} JucY[`|JV  
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Utility.log("Thread " + nThreadID + " is over!"); \9EjClfo  
bDownOver = true; E]r?{t`]  
//nPos = fileAccessI.write (b,0,nRead); w0unS`\4  
} |R:'\+E  
catch(Exception e){e.printStackTrace ();} wMN]~|z>  
} &K,i f  
} Vxt+]5X  
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//打印回应的头信息 5"H=zJ=r  
public void logResponseHead(HttpURLConnection con) \~wMfP8  
{ $ocdI
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for(int i=1;;i++) 9lE_nc  
{ >yDZ
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String header=con.getHeaderFieldKey(i); Y_P!B^z3  
if(header!=null) |y!A&d=xYn  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ,/unhfs1q  
Utility.log(header+" : "+con.getHeaderField(header)); DtnEi4h,  
else ],].zlN  
break; EoDA]6?Lj  
} -UT}/:a  
} O#r%>;3*  
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public void splitterStop() hE-M$LmN@  
{ g9F?z2^  
bStop = true; bg0

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} \l3h0R  
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} > Nr#O  
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/* +"@ .8m  
**FileAccess.java 2J;g{95z  
*//文件访问(定位，写) /Ci<xmP  
package NetFox; ;A[Q2(w+  
import java.io.*; $ME)#(  
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public class FileAccessI implements Serializable{ 9cm#56  
{(}By/_  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Y <qm{e  
RandomAccessFile oSavedFile; 9_s`{(0?  
long nPos; ?bu>r=oIO]  
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public FileAccessI() throws IOException ct}9i"H#1  
{ Xha..r  
this("",0); A5w6]:f2  
} gZ1?G-Q  
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public FileAccessI(String sName,long nPos) throws IOException <0?W{3NqI  
{ DlNX 3  
oSavedFile = new RandomAccessFile(sName,"rw"); |^H5^k "Bv  
this.nPos = nPos; ;*&-C9b  
oSavedFile.seek(nPos); Yz<1 wt7;  
} @s^-.z  
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public synchronized int write(byte[] b,int nStart,int nLen) @\I#^X5lv  
{ Rws3V"{`[  
int n = -1;
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try{ *uvQ\.  
oSavedFile.write(b,nStart,nLen); Xn\jO>[Ef  
n = nLen; #R RRu2  
} >lM l  
catch(IOException e) &jr3B;g!C  
{ KY
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e.printStackTrace (); N,U8YO  
} ;jTN| i'  
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return n; Y[S1$(K&*  
} >@AB<$A  
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} M& CqSd  
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/* 76` .Y  
**SiteInfoBean.java ,,|^%Ct']  
*/ ei5~&  
package NetFox; n?K  
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public class SiteInfoBean { #LN`X8Wz'  
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private String sSiteURL; //Site's URL t);/'3|  
private String sFilePath; //Saved File's Path Vs{|xG7WD  
private String sFileName; //Saved File's Name '$QB$2~V  
private int nSplitter; //Count of Splited Downloading File G9@0@2aY8  
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public SiteInfoBean() BDZ?Ez\Sg  
{//nSplitter的缺省值为5 xi;`ecqS<  
//default value of nSplitter is 5 RY*U"G0#w  
this("","","",5); qb` \)X]9  
}
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) dcWD(-  
{ jm r"D>  
sSiteURL= sURL; Q.c\/&  
sFilePath = sPath; ROZF)|l  
sFileName = sName; @!d{bQd,  
this.nSplitter = nSpiltter; *G9V'9  
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} !_Z&a  
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public String getSSiteURL() 01(AK%e  
{ *siFj CN<  
return sSiteURL; R,=fv  
} i
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public void setSSiteURL(String value) t.\dpBq  
{ %BB%pC  
sSiteURL = value; s=/v';5J2!  
} 57'4ljvYi  
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public String getSFilePath() yyy|Pw4:Z  
{ I[X772K  
return sFilePath; &~U ]~;@  
} N_q|\S>t/  
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public void setSFilePath(String value) 'a.qu9PJ  
{ 2Q:+
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sFilePath = value; ^&Y#)II  
} _``=cc  
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public String getSFileName() F`]2O:[  
{ _ZkI)o
 
return sFileName; GF=g<H M  
} Uq`'}Vo  
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public void setSFileName(String value) c6]D-YNFG  
{ FH+s s
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sFileName = value; \v)+.m?n  
} gCY';\f!  
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public int getNSplitter() kt$jm)UI~l  
{ XACm[NY_  
return nSplitter; ]-QA'Lq  
} qPfQy  
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public void setNSplitter(int nCount) hODWB&b  
{ 'Ne@e)s9  
nSplitter = nCount; 1c{DY  
} pBA7,z"`mP  
} ~Vjl7G\7i  
q.`NtsW!\+  
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/* h2;F
 
**Utility.java yd
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*/ 'u<juFr  
package NetFox; y;@:ulv[  
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public class Utility { QWHu
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public Utility() "vE4E|  
{ LOV)3{m  
.];=Pu^  
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} X1vd'
>  
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//线程睡眠 M}v/tRI  
public static void sleep(int nSecond) |64~K\X  
{ YcK|.Mq':  
try{ =h73s0]  
Thread.sleep(nSecond); F;0}x;:>  
} AoL2@C.C%D  
catch(Exception e) :yjKL^G>  
{ WWHoi{q  
e.printStackTrace (); ?R.j^S^  
} )iK6:s#  
} pOG1jI5<{8  
2'MZ s]??w  
//日志 Ffta](Z;  
public static void log(String sMsg) 7,9=uk>0\  
{ M,mvys$  
System.err.println(sMsg); L"Olwwmk  
} 8k1Dj1@0z  
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public static void log(int sMsg) (|1A?@sJ#h  
{ nq8C'Fo!6T  
System.err.println(sMsg); __GqQUQ  
} VUR|OV%  
} |02gupqqi  
i|*)I:SHU  
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/* \<TXS
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**TestMethod.java eHNyNVz  
*/ \%N!5>cZ{  
package NetFox; Oh6fj}eK  
5 -RsnF  
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public class TestMethod { RMWHN:9  
 =`s!;  
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public TestMethod() 2/=l|!JKLz  
{ ///xx/weblogic60b2_win.exe O]Qd<%V'x  
try{ =\:qo'l  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); s?,Ek  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); q0r>2c-d  
SiteFileFetch fileFetch = new SiteFileFetch(bean); |kV*Jc k  
fileFetch.start();
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} Zu("#cA.H  
catch(Exception e){e.printStackTrace ();} xx9 g
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} OCaq3_#tZ  
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public static void main(String[] args) !1{e|p 7  
{ q0R -7O(  
new TestMethod(); .-oxb,/  
} ?FF4zI~  
} kw
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