http断点续传简单实现（java)

/* "uG@gV  
**SiteFileFetch.java fwz-)?   
*/ {M P(*N  
package NetFox; *n2le7  
import java.io.*; ^,6c9Dxy  
import java.net.*; "\l#q$1h  
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public class SiteFileFetch extends Thread { lD@`xq.M;  
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SiteInfoBean siteInfoBean = null; //文件信息Bean
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long[] nStartPos; //开始位置 2~)r,.,  
long[] nEndPos; //结束位置 %%hG],w  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ,p9>/)l  
long nFileLength; //文件长度 R}HNi(%"  
boolean bFirst = true; //是否第一次取文件 dNT
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boolean bStop = false; //停止标志 G"nGaFT~  
File tmpFile; //文件下载的临时信息 H.*aVb$  
DataOutputStream output; //输出到文件的输出流 +VRM:&  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 2HF_kYZ  
public SiteFileFetch(SiteInfoBean bean) throws IOException Y3?)*kz%  
{ XSe\@t~&g  
siteInfoBean = bean; B
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//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); b!c2j   
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); I9O%/^5^[w  
if(tmpFile.exists ()) ]T1\gv1~  
{ )5/,B-+O"  
bFirst = false; $Lt'xW`8  
read_nPos(); p{oc}dWin  
} LV`tnt's  
else cOvdC4   
{ s1%th"e [  
nStartPos = new long[bean.getNSplitter()]; O("13cU  
nEndPos = new long[bean.getNSplitter()]; /DoSU>%hK  
} 91ndr@*|  
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} ]Wx?k7T  
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public void run() EdC/]  
{  } @4by<  
//获得文件长度 w>TTu: 7  
//分割文件 qcGsx2  
//实例FileSplitterFetch -DL"Yw}  
//启动FileSplitterFetch线程 dd:vQOF;  
//等待子线程返回 ZXC_kmBN/  
try{ J)._&O$  
if(bFirst) 0Q!/A5z  
{ !YENJJ  
nFileLength = getFileSize(); cN%@ nW0i  
if(nFileLength == -1) KK, t!a  
{ -xL^UcG0  
System.err.println("File Length is not known!"); |wGmu&fY  
} EClx+tz;`  
else if(nFileLength == -2) F-%Hw  
{ -SUK[<=X  
System.err.println("File is not access!"); aXh~w<5F  
} )8*}-z  
else <N,:w`g#  
{ L-1#n  
for(int i=0;i<nStartPos.length;i++) uo-1.[9ds  
{ }0AoV&75  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); @|EWif|  
} DAf0bh"  
for(int i=0;i<nEndPos.length-1;i++) jhH&}d9  
{ 3#N`n |UgC  
nEndPos = nStartPos[i+1]; g+3_ $qIQ+  
} A\ r}V-  
nEndPos[nEndPos.length-1] = nFileLength; tX~*.W:  
} *NCkC ~4  
} ?ZP@H _w6}  
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//启动子线程 qijQRxS  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ,Rdw]O  
for(int i=0;i<nStartPos.length;i++) (CInt_dBw~  
{ o^v]d7I8b  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Nj=0bg"Qg5  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), rr]-$]Q  
nStartPos,nEndPos,i); p9![8VU  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); cyBm,!  
fileSplitterFetch.start(); K@tELYb  
} -S7i':  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), O'h f8w  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); dF$&fo%  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", /p$+oA+  
nEndPos = " + nFileLength); TGHyBPJb  
// fileSplitterFetch[nPos.length-1].start(); (Rh$0^)A  
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y 'Ah
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//等待子线程结束 !3`X Gg  
//int count = 0; jx14/E+^  
//是否结束while循环 qi$nG_<<Z  
boolean breakWhile = false; %>Mcme>(W  
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while(!bStop) *JF7
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{ `Gh J)WA<  
write_nPos(); pU1miA '  
Utility.sleep(500); I(>j"H)cAF  
breakWhile = true; m ;yIFO  
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for(int i=0;i<nStartPos.length;i++) = ( 4l  
{
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if(!fileSplitterFetch.bDownOver) h?p!uQ  
{ {LBL8sG  
breakWhile = false; lf#5X)V  
break; = OzpI  
} jEn9T  
} $bl<mG%#9  
if(breakWhile) p %hv
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break; 9Y+7o%6e  
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OmlM9cXm^4  
//count++; BvP++,a&Sa  
//if(count>4) ]z8Th5a?o  
// siteStop(); '&/~Sh$%  
} |_OoD9,M  
z}F^HQ1  
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System.err.println("文件下载结束！"); P"+R:O\!g  
} XZT|ID_u"  
catch(Exception e){e.printStackTrace ();} j{
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} #J^ >7v  
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//获得文件长度 gts09{"}Y  
public long getFileSize() l ;S_J^S  
{ )j!%`g  
int nFileLength = -1; YmD~&J  
try{ e[6Me[b  
URL url = new URL(siteInfoBean.getSSiteURL()); s
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); }=A+W2D  
httpConnection.setRequestProperty("User-Agent","NetFox"); IZuP{7p$  
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int responseCode=httpConnection.getResponseCode(); \+"Jg/)ij  
if(responseCode>=400) [9yd29pQ]  
{ ]e$n;tuW  
processErrorCode(responseCode); .E;}.X  
return -2; //-2 represent access is error Ld 0j!II(  
} |XmzqX%  
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String sHeader; GJ:oUi  
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for(int i=1;;i++) z{/#/,V5D4  
{ 
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//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); vAjog])9s  
//Utility.log(in.readLine()); h+w1 D}*  
sHeader=httpConnection.getHeaderFieldKey(i); WW-}c;cnK  
if(sHeader!=null) JFq<sY!  
{ >7z(?nQYT^  
if(sHeader.equals("Content-Length")) lo-VfKvy  
{ 5a4i)I63o  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); %~P3t=r  
break; ,YRBYK:  
} #Q BW%L  
} ),H1z`c&I  
else <) -]'@*c  
break; 5=V29  
} SNf~%B?`L  
} 5"bg8hL  
catch(IOException e){e.printStackTrace ();} [AYJ(H/  
catch(Exception e){e.printStackTrace ();} zb s7G  
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Utility.log(nFileLength); (yoF  
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return nFileLength; 7Kpv fyL{  
} G?!8T91;  
*+(eH#_2/  
AC!yc(^<  
//保存下载信息（文件指针位置） nI] zRduC  
private void write_nPos() S5r.so
 
{ ^S 45!mSb  
try{ n8JM 0 U-  
output = new DataOutputStream(new FileOutputStream(tmpFile)); > w SI0N  
output.writeInt(nStartPos.length); MRT<hB  
for(int i=0;i<nStartPos.length;i++) ]Bs{9=2  
{ k%iwt]i%  
// output.writeLong(nPos); "whs
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output.writeLong(fileSplitterFetch.nStartPos); fcy4?SQ.<i  
output.writeLong(fileSplitterFetch.nEndPos); /N,\st  
} ,eSpt#M  
output.close(); 7jGfQ  
} 5mZwg(si  
catch(IOException e){e.printStackTrace ();} CZ>Ujw=&k  
catch(Exception e){e.printStackTrace ();} qRz /$|.  
} nRT]oAi  
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//读取保存的下载信息（文件指针位置） w-C%,1F,/  
private void read_nPos() TaF;PGjVw  
{  QB !%  
try{ <U8w#dc  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); T7o7t5*  
int nCount = input.readInt(); q s:T
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nStartPos = new long[nCount]; NC iBn>=:  
nEndPos = new long[nCount]; bf.yA:~U  
for(int i=0;i<nStartPos.length;i++) 70EH~  
{ hZWkw{c  
nStartPos = input.readLong(); eU.C<Tv:8  
nEndPos = input.readLong(); 2B
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} x:h)\%Dg<  
input.close(); c2L\m*^o  
} !#W3Q  
catch(IOException e){e.printStackTrace ();} B ]sVlbt  
catch(Exception e){e.printStackTrace ();} M.bkFuh  
} PDLps[a  
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private void processErrorCode(int nErrorCode) "'/+}xM"5  
{ aj=-^iGG  
System.err.println("Error Code : " + nErrorCode); BkY#wJ'  
} ab#z&jg!  
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//停止文件下载 :Ys ;)W+R  
public void siteStop() X":2o|R  
{ KTwP.!<v  
bStop = true; GkI{7GD:z  
for(int i=0;i<nStartPos.length;i++) JIqg[Mao  
fileSplitterFetch.splitterStop(); t;u)_C,bmP  
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} /c6]DQ<?  
} o)$eIu}Wg  
//负责部分文件的抓取 8VuLL<\|  
**FileSplitterFetch.java -BWWaL  
*/ cl |}0Q5  
package NetFox; "xn,'`a  
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import java.io.*; x(p/9$.#  
import java.net.*; m\E=I5*/  
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public class FileSplitterFetch extends Thread { y=jZ8+M   
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String sURL; //File URL B\l0kiNT  
long nStartPos; //File Snippet Start Position zMM~4?4  
long nEndPos; //File Snippet End Position .u`A4;;Gw  
int nThreadID; //Thread's ID {xOzxLB;  
boolean bDownOver = false; //Downing is over \Co Z+  
boolean bStop = false; //Stop identical i6y=3k  
FileAccessI fileAccessI = null; //File Access interface e@S\7Ks  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException EMdU4YnE"  
{ qT&zg@m  
this.sURL = sURL; . ~a~(|  
this.nStartPos = nStart; h cu\c+
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this.nEndPos = nEnd; ?6L8#"=  
nThreadID = id; 9
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fileAccessI = new FileAccessI(sName,nStartPos);//定位 d`%7Pk  
} b!teSf  
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public void run() 8@|{n`n]  
{ \< a^5'  
while(nStartPos < nEndPos && !bStop) T)Q_dF.N  
{ 6Q{OM:L/;.  
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try{ $BG]is,&5  
URL url = new URL(sURL); 91DevizXx  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); z46Sh&+  
httpConnection.setRequestProperty("User-Agent","NetFox"); tV4wkS=R|  
String sProperty = "bytes="+nStartPos+"-"; =h+-1zp{M^  
httpConnection.setRequestProperty("RANGE",sProperty); =kzHZc  
Utility.log(sProperty); _1WA:7$C  
.Yz^r?3t  
/zr)9LQY0  
InputStream input = httpConnection.getInputStream(); _a_T`fE&de  
//logResponseHead(httpConnection); Bgp%hK  
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byte[] b = new byte[1024]; JNP6qM  
int nRead; c0w1 N]+Ne  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ps:E(\  
{ n36iY'<)G  
nStartPos += fileAccessI.write(b,0,nRead); "9N;&^I  
//if(nThreadID == 1) gA3f@7}d  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); }]<|`FNc  
} fN:FD`  
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H ]!P[?  
Utility.log("Thread " + nThreadID + " is over!"); ;lt8~ea  
bDownOver = true; c `.BN(  
//nPos = fileAccessI.write (b,0,nRead); 77wod}h!:  
} ,DEcCHr,  
catch(Exception e){e.printStackTrace ();} ^g"p}zf L"  
} Vi
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} QjYw^[o  
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//打印回应的头信息 .CNwuN\  
public void logResponseHead(HttpURLConnection con) aSgKh  
{ rEbH<|  
for(int i=1;;i++) .'h^  
{ oiD{Z  
String header=con.getHeaderFieldKey(i); ml!c0<  
if(header!=null) BxZ7Bk  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); kpNp}b8']  
Utility.log(header+" : "+con.getHeaderField(header)); 'Z%1Ly^b  
else ->7zVAX  
break; 0F%?<: &  
} yL -}E  
} O`aNNy  
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public void splitterStop() sI09X6)  
{ rfzzMV  
bStop = true; rhly.f7N=A  
} ;E>#qYC6  
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} `0MQL@B  
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/* xuVc1jJH  
**FileAccess.java 17 
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*//文件访问(定位，写) 7#7|+%W0  
package NetFox; x"cB8bZ!$  
import java.io.*; IYH4@v/#  
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public class FileAccessI implements Serializable{ H$pgzNL  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 DF g
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RandomAccessFile oSavedFile; 8U4In[4  
long nPos; ~[~#PO  
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public FileAccessI() throws IOException 4^d).{&X  
{ c++q5bg@)  
this("",0); JZE@W-2  
} j%J>LeTca  
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public FileAccessI(String sName,long nPos) throws IOException Ww#!-,*]o  
{ +Yc
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oSavedFile = new RandomAccessFile(sName,"rw"); wjgFe]  
this.nPos = nPos; \'iy(8i  
oSavedFile.seek(nPos); (hIo0.  
} 9wO2`e )  
/NobS'd  
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public synchronized int write(byte[] b,int nStart,int nLen) ?,%PemN  
{ whrDw1>(  
int n = -1; BNFYUcVP  
try{ S_RP&+!7  
oSavedFile.write(b,nStart,nLen); |Q";a:&$  
n = nLen; ,e'"SVQc  
} M=SrZ,W  
catch(IOException e) >J_P[v  
{ {))Cb9'  
e.printStackTrace (); |YfJ#Agm+  
} ?[Ma" l>  
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return n; {K?e6-N(z  
} >J)4e~9EJ2  
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} y=[{:
 
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/* rls{~ZRl  
**SiteInfoBean.java u]ps-R_$G  
*/ N%
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package NetFox; UdA,.C0  
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public class SiteInfoBean { Fdq5:v?k  
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private String sSiteURL; //Site's URL *&R|0I{>  
private String sFilePath; //Saved File's Path V)ag ss w?  
private String sFileName; //Saved File's Name v$5D&Tv  
private int nSplitter; //Count of Splited Downloading File { 9\/aXPS  
2t45/:,  
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public SiteInfoBean() b.kV>K"X3  
{//nSplitter的缺省值为5 H\9ePo\b~  
//default value of nSplitter is 5 P_75-0G  
this("","","",5); i*A_Po  
}
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) &n0Ag]$P  
{ =Mxu,A  
sSiteURL= sURL; /g!Xe]Ss  
sFilePath = sPath; $&Z#2 X.  
sFileName = sName; NVB#=!
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this.nSplitter = nSpiltter; P7l3ZH( g  
t -fmA?\  
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} AI9922}*  
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public String getSSiteURL() z3>4 xn{  
{ ap
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return sSiteURL; EVA&By6_k  
} UQ@szE  
&0J8ICd=  
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public void setSSiteURL(String value) ,^eOw
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{ U%;E:|  
sSiteURL = value; A* Pz-z>z  
} D*sL&Rt][Y  
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Bqb`WX[<`  
public String getSFilePath() 'R42N3|F  
{ zvdIwV&oT  
return sFilePath; S1C#5=  
} "I{Lcn~!@  
i<=2 L?[.I  
6
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public void setSFilePath(String value) z92Xc  
{ >!tfvM2X{  
sFilePath = value; kV!1k<f  
} D-x*RRkpp  
R
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public String getSFileName() [ <k&]Kv  
{ BJ fBYH,M  
return sFileName; B7oUS}M  
} 2=1qmQE  
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s
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public void setSFileName(String value) ?wn<F}UH  
{ OqmW lN.?  
sFileName = value; ,6"[vb#*3  
} aOsc_5XDR;  
%e|UA-(  
{]N7kY.W  
public int getNSplitter() N$.ls48a4-  
{ 7;]IlR6  
return nSplitter; `Ao"fRv#  
} +$/NTUOP  
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cFuQ>xR1  
public void setNSplitter(int nCount) ?MFXZ/3(ba  
{ Q7/Jyx|  
nSplitter = nCount; bBGg4{  
} 7_rDNK@e  
} u bZ`Y$  
e:_[0#  
mmCGIX  
/* EZhk(LE  
**Utility.java mGoC8t}iP  
*/
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package NetFox; P4c}@Mq3  
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public class Utility { ,JPDPI/a  
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public Utility() _)4zm  
{ BIg2`95F|  
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} s5MG#M 9  
KxfH6:\RB  
//线程睡眠 k RSY;V  
public static void sleep(int nSecond) U<'z,P
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{ IA}.{zY~|  
try{ 2|`Mb~E;  
Thread.sleep(nSecond); s=z$;1C  
} u~mpZ"9$ 3  
catch(Exception e) %O7?:#_  
{ ?}u][akM  
e.printStackTrace (); [d>2F  
} H$ :BJ$x@  
} !thFayq  
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//日志 T/J1 b-  
public static void log(String sMsg) oDGBC  
{ F:.8O ,%u  
System.err.println(sMsg); v^[!NygShs  
} l SuNZYaO  
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]xIgP%  
public static void log(int sMsg) c]ga)A(  
{ ww'B!Ml>F  
System.err.println(sMsg); ,I,Zl.5  
} [g+WL\1  
} =OKUSHu@V  
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?;w\CS^Qu  
/* &iy7It  
**TestMethod.java 5D3&6DCH  
*/ M[_Ptqjb  
package NetFox; X[?E{[@Z  
zNEN[  
t!>0^['g4  
public class TestMethod { 8Kn}o@Yd  
ICTjUQP  
/~?[70B}E  
public TestMethod() yV&]i-ey  
{ ///xx/weblogic60b2_win.exe Oj2=&uz  
try{ Q H>g-@  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ";n%^I}  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); RGY#0.Z}  
SiteFileFetch fileFetch = new SiteFileFetch(bean); bPl'?3  
fileFetch.start(); /u"Iq8QA  
} 7a.iT-*  
catch(Exception e){e.printStackTrace ();} Vu<mOuh
 
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} \z.p [;'ir  
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[[}ukG4  
public static void main(String[] args) -,$:^4  
{ oiz]Bd  
new TestMethod(); z34+1d  
} Z_T~2t  
} *r6v9  
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