http断点续传简单实现（java)

/* A+AqlM+$i  
**SiteFileFetch.java lbMb  
*/ 1aKY+4/G  
package NetFox; hH>t  
import java.io.*; (c_E*>c)  
import java.net.*; HI55):Eb  
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public class SiteFileFetch extends Thread { sdrALl;w|  
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SiteInfoBean siteInfoBean = null; //文件信息Bean f
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long[] nStartPos; //开始位置 ki39$A'8  
long[] nEndPos; //结束位置 Y}QtgZEt  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 aVEg%8  
long nFileLength; //文件长度 ;>bcI).  
boolean bFirst = true; //是否第一次取文件 e~oI0%xl^  
boolean bStop = false; //停止标志 cE'MSB  
File tmpFile; //文件下载的临时信息 (U4]d`  
DataOutputStream output; //输出到文件的输出流 -Z9e}$q$,  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 7vZznN8e  
public SiteFileFetch(SiteInfoBean bean) throws IOException 63 F@Ft  
{ <;G.(CK@n  
siteInfoBean = bean; |bA\>%~  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); @uXF(KDX  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); gm'8,ZL  
if(tmpFile.exists ()) 7Rwn{]r  
{ Jsde+G,N  
bFirst = false; k"7l\;N  
read_nPos(); 4CCtLHb  
} rE)lt0m
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else  *Yj!f68  
{ yy8h8{=g  
nStartPos = new long[bean.getNSplitter()]; k  <SFl  
nEndPos = new long[bean.getNSplitter()]; 8iQ8s;@S&>  
} <A"[Wk  
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} EbXWCD  

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public void run() `3GYV|LeQ  
{ 4Cm+xAXG  
//获得文件长度 l7vU{Fd-h^  
//分割文件 $IUe](a{d  
//实例FileSplitterFetch K FMx(fD  
//启动FileSplitterFetch线程 JlaT -j  
//等待子线程返回 !'#Y-"=ypk  
try{ ,0k3Qi%  
if(bFirst) <9Sg,ix't  
{ jxeZ,w o  
nFileLength = getFileSize(); cug=k  
if(nFileLength == -1) ol#| .a2O  
{ z"D'rHxy  
System.err.println("File Length is not known!"); `YL)[t? V  
} xQA6!j  
else if(nFileLength == -2) mLGbwm'K  
{ :^bjn3b  
System.err.println("File is not access!"); L JW0UF|  
} i?^lEqy[  
else uz U2)n3y  
{ D05JQ*  
for(int i=0;i<nStartPos.length;i++) 0[L)`7  
{ Le,e,#hiY  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ip)gI&kN`z  
} 3+~m9:9  
for(int i=0;i<nEndPos.length-1;i++) u"hv _ml  
{ .^hk^r  
nEndPos = nStartPos[i+1]; n.L/Xp@gc  
} lJ>OuSd  
nEndPos[nEndPos.length-1] = nFileLength; K."%PdC  
} QP?eKW9 :  
} nA1059B  
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//启动子线程 sR;^7(f!m  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length];
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for(int i=0;i<nStartPos.length;i++) (Vz\02,K  
{ _@] uHp|  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(),
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), fg?4/]*T6  
nStartPos,nEndPos,i); 9jkaEn>m^  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); z\g6E/%%  
fileSplitterFetch.start(); P70]
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} hH.X_X?d%  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), #t8{z~t3  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); SSrYFu"  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 0YsBAfRG  
nEndPos = " + nFileLength); P;' xa^Y  
// fileSplitterFetch[nPos.length-1].start(); V!&O5T(~  
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n-)Xs;`2  
//等待子线程结束 ;)7GdR^K  
//int count = 0; u6#FG9W7  
//是否结束while循环 @a]O(S>Ub  
boolean breakWhile = false; y/9aI/O'
  
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while(!bStop) \ )'`F; P  
{ 0D.qc8/V4.  
write_nPos(); *f ;">(`o*  
Utility.sleep(500); ZIr&_x#e  
breakWhile = true; +=o?&  
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for(int i=0;i<nStartPos.length;i++) ipi^sCYp  
{ bsosva+  
if(!fileSplitterFetch.bDownOver) uW{;
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{ 40i]I@:JK  
breakWhile = false; u|eV'-R)s  
break; w$fP$ \+  
} -:]-g:;/  
} 2Y-NxW^]  
if(breakWhile) ~u^MRe|`  
break; G\4*6iw:  
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//count++; XI/LVP,.  
//if(count>4) .W*"C  
// siteStop(); yzH[~O7  
} knb 9s`wR  
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System.err.println("文件下载结束！"); tQYkH$e`/{  
} YQ _]Jv k  
catch(Exception e){e.printStackTrace ();} lk/[xQ/  
} E/5/5'gBJO  
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//获得文件长度 +`]AutNv  
public long getFileSize() %Ix   
{ 6aq=h`Y  
int nFileLength = -1; Z^_-LX:%  
try{ 8nKb mjM  
URL url = new URL(siteInfoBean.getSSiteURL()); D.:6X'hp  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); tOT(!yz  
httpConnection.setRequestProperty("User-Agent","NetFox"); vOV$Hle  
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int responseCode=httpConnection.getResponseCode(); s"-gnW  
if(responseCode>=400) l1#F1q`^t  
{ zg+6< .
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processErrorCode(responseCode); j.O+e|kxU  
return -2; //-2 represent access is error <Y"h2#M"  
} 3-6Lbe9H  
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String sHeader; e4mAKB s!  
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for(int i=1;;i++) (@nEe?  
{ )8@|+'q  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 0T7c=5z4W  
//Utility.log(in.readLine()); ms/!8X$Mz  
sHeader=httpConnection.getHeaderFieldKey(i); t;/s^-}  
if(sHeader!=null) @0[#XA_>  
{ IDn$w^"  
if(sHeader.equals("Content-Length")) RTQtXv6m
D  
{ ;w(tXcXZ  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 5e|yW0o  
break; ^=@`U_(,G  
} ({!S!k  
} sp8P[W1a  
else Ra)AQ n  
break; 2Y1y;hCK  
} q<Z`<e  
} ["N_t:9I  
catch(IOException e){e.printStackTrace ();} peD7X:K\s  
catch(Exception e){e.printStackTrace ();} <Gw>}/-^  
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Utility.log(nFileLength); n"
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return nFileLength; .8]buM5_G  
} WWgJ !Uz  
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//保存下载信息（文件指针位置） opfg %*  
private void write_nPos()
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{ =Ohro'   
try{ 9(pF!}1%\  
output = new DataOutputStream(new FileOutputStream(tmpFile)); c@|f'V4  
output.writeInt(nStartPos.length); (MzThGJK_  
for(int i=0;i<nStartPos.length;i++) vB Vg/  
{ 'BX U'  
// output.writeLong(nPos); 1TlMB  
output.writeLong(fileSplitterFetch.nStartPos); p>h}k_s  
output.writeLong(fileSplitterFetch.nEndPos); 4L
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} 5
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output.close(); IylfMwLC  
} <V1y^EW0  
catch(IOException e){e.printStackTrace ();} e!N%  
catch(Exception e){e.printStackTrace ();} uFnq3m^u  
} <Gj]XAoe%  
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//读取保存的下载信息（文件指针位置） EYR%u'&7'  
private void read_nPos() t*wV<b  
{ YJB/*SV^  
try{ 1 &-%<o  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Pf#DBW*  
int nCount = input.readInt(); F5 7Kr5X  
nStartPos = new long[nCount];
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nEndPos = new long[nCount]; 0,1)Sg*  
for(int i=0;i<nStartPos.length;i++) Yv"
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{ nJR(lXWO  
nStartPos = input.readLong(); p+}eP|N  
nEndPos = input.readLong(); U"OA m
}  
} %9b TfX"  
input.close(); seiE2F[  
} % |G"ZPO?  
catch(IOException e){e.printStackTrace ();} plgiQr #  
catch(Exception e){e.printStackTrace ();} kb[+II  
} 1O+$"5H  
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private void processErrorCode(int nErrorCode) !m?W+z~J  
{ N{?Qkkgx  
System.err.println("Error Code : " + nErrorCode); ;aImz*1%t  
} 9 =D13s(C  
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cdTG ]n  
//停止文件下载 `o6T)49  
public void siteStop() # 66vkf*  
{ K-n]m#U4o  
bStop = true; O6]X\Cwj%  
for(int i=0;i<nStartPos.length;i++) Am=O-; b'8  
fileSplitterFetch.splitterStop(); 8_{XrTw(  
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} VL2ACv(  
} m_b_)/  
//负责部分文件的抓取 9ZG__R3B1\  
**FileSplitterFetch.java N[wyi&m4  
*/ YLid2aF  
package NetFox; zfK3$|  
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import java.io.*; L87=*_!B;  
import java.net.*; ?}<Wmy2A  
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public class FileSplitterFetch extends Thread { O>>%lr|  
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String sURL; //File URL GL3olKnL  
long nStartPos; //File Snippet Start Position wu19Pg?F  
long nEndPos; //File Snippet End Position !N\i9w}  
int nThreadID; //Thread's ID `:5W1D(  
boolean bDownOver = false; //Downing is over &I?d(Z=:\  
boolean bStop = false; //Stop identical 'Ug-64f>  
FileAccessI fileAccessI = null; //File Access interface 92g&,Wb  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Q3aZB*$
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{ U&L?IT=x  
this.sURL = sURL; $GX9-^og=T  
this.nStartPos = nStart; ThYHVJ[;  
this.nEndPos = nEnd; =
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nThreadID = id; "U iv[8B  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 C%;J9(r  
} z>O=. Ku6  
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public void run() T<~?7-O"  
{ u;=a=>05IR  
while(nStartPos < nEndPos && !bStop) R;F z"
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{
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try{ mY!&*nYn|  
URL url = new URL(sURL); z#t;n  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); #H&`wMZZ:  
httpConnection.setRequestProperty("User-Agent","NetFox"); _sC kBDl-  
String sProperty = "bytes="+nStartPos+"-"; ]B9Ut&mF;  
httpConnection.setRequestProperty("RANGE",sProperty); nVv=smVOt  
Utility.log(sProperty); rWxQ;bb#  
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InputStream input = httpConnection.getInputStream(); p^?]xD(  
//logResponseHead(httpConnection); "D.`:9sk0  
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byte[] b = new byte[1024]; KPB^>,T2{  
int nRead; E~'Q
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while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) {igVuZ(>en  
{ S_Ug=8r4  
nStartPos += fileAccessI.write(b,0,nRead); h-=lZ~W~  
//if(nThreadID == 1) 1g bqHxWI  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); A#8Dv&$Pr  
} 2^T`> ?{X  
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Utility.log("Thread " + nThreadID + " is over!"); +
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bDownOver = true; yfCdK-9+B  
//nPos = fileAccessI.write (b,0,nRead); x
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} XonI   
catch(Exception e){e.printStackTrace ();} ;-@v1I;  
} LGF5yRk  
} (| X?  
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//打印回应的头信息 LFT)_DG7(  
public void logResponseHead(HttpURLConnection con) D}6~2j  
{ B kWoK/f4  
for(int i=1;;i++) ;&MI M`&$  
{ 3F|#nq  
String header=con.getHeaderFieldKey(i); 89X`U)W
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if(header!=null) 3CArUP  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); '}.Z' %;  
Utility.log(header+" : "+con.getHeaderField(header)); |*-&x:p7O  
else C le
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break; B0#JX MX9  
} '+*{u]\  
} Qfd4")zhG  
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public void splitterStop() D4e!A@LJ  
{ d1=fA%pJ  
bStop = true; yPhTCr5pK  
} ^-GzWT  
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} }*s%|!{H  
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/* >^q7:x\  
**FileAccess.java haW*W=kv)  
*//文件访问(定位，写) `bx}!;{lx  
package NetFox; ~v+A6N:qC  
import java.io.*; ]E!b&  
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public class FileAccessI implements Serializable{ xvx+a0 A  
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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 P>s3Rh3:  
RandomAccessFile oSavedFile; uiQRRT  
long nPos; u~y0H  
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public FileAccessI() throws IOException u^Sa{Jk=  
{ 6)_svtg  
this("",0); 7_*k<W7|  
} !9ytZR*  
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public FileAccessI(String sName,long nPos) throws IOException 6mAaFDI,R  
{ Q"+)xj  
oSavedFile = new RandomAccessFile(sName,"rw"); z;#]xCV  
this.nPos = nPos; ;:5Ahfo \  
oSavedFile.seek(nPos); rE[:j2HF  
} WY)*3?  
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public synchronized int write(byte[] b,int nStart,int nLen)  ^D.u   
{ 2Sg^SZFH+o  
int n = -1; Z>t,B%v  
try{ HJ]9e  
oSavedFile.write(b,nStart,nLen); Q?uHdmY*X  
n = nLen; MaS"V`NI  
} X}@'FxIF  
catch(IOException e) \J0fr'(S  
{ aHR&6
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e.printStackTrace (); T4lE-g2%M  
} M8p6f)l3  
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return n; A<$w }Fy;  
} {I:nza  
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} N" =$S|Gs  
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/* @?!&M c2  
**SiteInfoBean.java EK=PY  
*/ cq#=Vb  
package NetFox; &hco3HfW  
j :$Ruy  
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public class SiteInfoBean { #P)(/>nF  
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private String sSiteURL; //Site's URL 'Xb
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private String sFilePath; //Saved File's Path )ld`2) 4  
private String sFileName; //Saved File's Name qvN`46c  
private int nSplitter; //Count of Splited Downloading File >5c38D7k)  
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public SiteInfoBean() :|PI_ $4H  
{//nSplitter的缺省值为5 Y0Bd[  
//default value of nSplitter is 5 n{8v^x  
this("","","",5); Q@aDa8Z  
} eX3|<Bf  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 3^-yw`  
{
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sSiteURL= sURL; 9JBVG~m+  
sFilePath = sPath; >uy(N  
sFileName = sName; ^P~NE#p5  
this.nSplitter = nSpiltter; qtYVX:M@,  
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} GX,)~Syw*  
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public String getSSiteURL() *DS>#x@3*i  
{ V:*6R/Ft  
return sSiteURL; {T'M4y=)i  
} gt|:K)[,6  
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public void setSSiteURL(String value) }Jm~b9j  
{ *)xjMTJ%  
sSiteURL = value; )7;E,m<:tO  
} i{2ny$55h  
nz_1Fu>g|  
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public String getSFilePath() 56 [+;*  
{ `Ti?hQm/  
return sFilePath; }+dDGFk  
} rGUu K0L&  
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public void setSFilePath(String value) D5$|vv1  
{ vHM,_I{  
sFilePath = value; cu )w6!f  
} cVuT|b^  
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public String getSFileName() gvCQ![  
{ LyNLz m5  
return sFileName; HtAO9  
} 6O| rI>D  
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public void setSFileName(String value) N"-U)d-.  
{ eiJ~1HX)  
sFileName = value; [|tlTk  
} 2 i97  
vNSeNS@jxC  

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public int getNSplitter() L.Tu7+M4  
{ Rg\D-F6:  
return nSplitter; Yc2dq e>  
}  ?~=5x  
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public void setNSplitter(int nCount) Apbgm[m|{  
{ "/0Vvy_|  
nSplitter = nCount; E@CK.-N|  
} nl+8C}=u  
} 5j>olz=n}  
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BXa.XZ<n(  
/* O\q-Ai  
**Utility.java 5nS}h76mZ  
*/ n0%5mTUN  
package NetFox; {VT**o  
tNC;CP#R+  
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public class Utility { bsdT>|gW  
7_CX6:  
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public Utility() DSL3+%KF#  
{ pIl[)%F  
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} e`bP=7`
0  
nQ08(8  
//线程睡眠 J!d=aGY0-  
public static void sleep(int nSecond) _|wnmeL*  
{ 'H-hp   
try{ SlI wLv^  
Thread.sleep(nSecond); ui<Mnm_T;d  
} =?[:Nj636  
catch(Exception e) Ib2n Bg>j  
{ `2hLs _  
e.printStackTrace (); j026CVL  
} &EJ/Rl
 
} EL(BXJrx{  
&?Z<"+B8S  
//日志 Kj/Lcx;bh  
public static void log(String sMsg) B_S))3   
{ :4[_&]H  
System.err.println(sMsg); E'^ny4gL  
} <$Djags,F  
eqk.+~^  
@nOuFX4  
public static void log(int sMsg) h
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{ 2?kVbF  
System.err.println(sMsg); )0zg1z  
} vQ8$C 3  
}  T
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/* : `,#z?Rk  
**TestMethod.java ^f9>tI{  
*/ &(h@]F!  
package NetFox; i4lB]k  
8@r>`c  
P5__[aTD  
public class TestMethod { J3hhh(  
s:oj
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2/ejU,S  
public TestMethod() F%$lcQ04%  
{ ///xx/weblogic60b2_win.exe &Z%'xAOGR  
try{ o.wXaS8  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); `2`h4[^ [X  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); :PNhX2F  
SiteFileFetch fileFetch = new SiteFileFetch(bean); (dP9`Na]  
fileFetch.start(); 
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} x LGMN)@r  
catch(Exception e){e.printStackTrace ();} 1rV9dM#F  
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} d?><+!a  
`HILsU=|  
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public static void main(String[] args) d>wG6Z,|  
{ 'y7<!uo?  
new TestMethod(); n<Ki.;-ZE  
} 4KY@y?H g  
} }[OEtd{  
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