http断点续传简单实现（java)

/*  J2Qt!-  
**SiteFileFetch.java 5Z=GFKf|  
*/ ZzP&Zrm  
package NetFox;
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import java.io.*; 4RH>i+)pS\  
import java.net.*; 5s>>] .%  
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public class SiteFileFetch extends Thread { +Z]}ce u"  
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SiteInfoBean siteInfoBean = null; //文件信息Bean tC.etoh  
long[] nStartPos; //开始位置 !HeQMz  
long[] nEndPos; //结束位置 u7 <VD  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 *uKYrs [  
long nFileLength; //文件长度 u_FN'p=.  
boolean bFirst = true; //是否第一次取文件 wbg?IvY[  
boolean bStop = false; //停止标志 K1&t>2=%  
File tmpFile; //文件下载的临时信息 _3#_6>=M  
DataOutputStream output; //输出到文件的输出流 $)KNpdXh  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） rMw$T=Oi  
public SiteFileFetch(SiteInfoBean bean) throws IOException k"m+i  
{ ~3%aEj  
siteInfoBean = bean; abS3hf  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 0w vAtK|Q  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 8I<j"6`+Q  
if(tmpFile.exists ()) Z&7Yl(|  
{ I$XwM  
bFirst = false; p1T0FBV L  
read_nPos(); 6 B7F  
} |qU~({=b  
else 7$8DMBqq  
{ 7loWqZ  
nStartPos = new long[bean.getNSplitter()]; 1qp
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nEndPos = new long[bean.getNSplitter()]; ]u:Ij|.'y0  
} Yjl:i*u/  
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} ]LMtZUz  
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public void run() GgE 38~A4  
{ qa4j>;  
//获得文件长度 pr1kYMrqri  
//分割文件 dqi31e{*2\  
//实例FileSplitterFetch jLw|F-v-l<  
//启动FileSplitterFetch线程 zQ(`pld  
//等待子线程返回 dl6Ju  
try{ 6QNZ/Ox:  
if(bFirst) ,pUB[w\  
{ o@L '|#e  
nFileLength = getFileSize(); :!FGvR6  
if(nFileLength == -1) $2a_!/  
{ &y-z[GR[{  
System.err.println("File Length is not known!"); '>Thn{  
} <y#@v  G  
else if(nFileLength == -2) <X?xr f  
{ P~PM$e  
System.err.println("File is not access!"); /PG%Y]l0b  
} ViUx^e\
  
else a|k*A&5u2  
{ Fw^^sB  
for(int i=0;i<nStartPos.length;i++) .Y }k@T40a  
{ :*cd$s  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); pi/&WMZ<  
} /74)c~.W  
for(int i=0;i<nEndPos.length-1;i++) -oY8]HrXfK  
{ OD?y  
nEndPos = nStartPos[i+1]; c4bvJy8  
} PK&X
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nEndPos[nEndPos.length-1] = nFileLength; .g.glQ_~=  
} Vygh|UEo  
} /sqfw,h@  
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//启动子线程 V=Z%y$1Bc  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; jV<5GWq  
for(int i=0;i<nStartPos.length;i++) Wxi;Tq9C@_  
{ 51ILR9 Bc_  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), q35=_'\W  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), TjpAJW@-  
nStartPos,nEndPos,i); INRRA  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); r>rL[`p(2  
fileSplitterFetch.start(); 7}(YCZny5  
} }$* z:E  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), gA19f  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ~W3t(\B'  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 8sq0 BH  
nEndPos = " + nFileLength); "po;[ Ia2  
// fileSplitterFetch[nPos.length-1].start(); SXV2Y-  
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//等待子线程结束 -:Q"aeC5  
//int count = 0; BiZYGq  
//是否结束while循环 +KIBbXF7  
boolean breakWhile = false; `'pfBVBz  
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while(!bStop) f^Q)lIv  
{ M1*x47bN  
write_nPos(); $M1;d1e6'  
Utility.sleep(500); V! .I>  
breakWhile = true; i{r[zA]$  
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for(int i=0;i<nStartPos.length;i++) =$_kkVQ$  
{ FWLLbL5t  
if(!fileSplitterFetch.bDownOver) D$`$4mX@hP  
{ ( ;KTV*1  
breakWhile = false; /5Yl, P  
break; O`;o"\P<  
} Z0M|Bv9_  
} w(Q{;RNM;  
if(breakWhile) u!McPM8Yk  
break; ]zI*}(adu  
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//count++; R l)g[s  
//if(count>4) OZe`>Q6  
// siteStop(); 0.B'Bvn=s2  
} >ffQ264g=i  
:6Gf@Z&+  
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System.err.println("文件下载结束！"); c >xHaA:V  
} 6L-3cxqf\  
catch(Exception e){e.printStackTrace ();} NHhKEx0Gtu  
} C0&ZQvvy1:  
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//获得文件长度 eqyUI|e  
public long getFileSize() gc W'  
{ Z jXn,W]~  
int nFileLength = -1; 9]|C$;kw@  
try{ 2hb>6Z;r]K  
URL url = new URL(siteInfoBean.getSSiteURL()); pwNF\ ={  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ,fhK  
httpConnection.setRequestProperty("User-Agent","NetFox"); IG!(q%Gf  
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int responseCode=httpConnection.getResponseCode(); ]5e|W Q>*X  
if(responseCode>=400) >ni0:^vp  
{ )p{,5"0u  
processErrorCode(responseCode); SjvSnb_3  
return -2; //-2 represent access is error :VX2&*  
} _DYe<f.  
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String sHeader; perhR!#J  
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for(int i=1;;i++) H2yPVJ\Y)"  
{ cEGR?4z  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Y,-!QFS#  
//Utility.log(in.readLine()); *EFuK8 ;  
sHeader=httpConnection.getHeaderFieldKey(i); JcC2Zn6  
if(sHeader!=null) `X(H,Q}*;  
{ NH+N+4dEO  
if(sHeader.equals("Content-Length")) ~e686L0j  
{ E=ObfN"ge  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); >oapw5~5  
break; oKPG0iM:  
} !^Q4ZL,-  
} r<DPh5ReY  
else D4T(Dce  
break; H?;@r1ZAn  
} ~NIqO4 D  
} _:KeSskuO  
catch(IOException e){e.printStackTrace ();} 96%N  
catch(Exception e){e.printStackTrace ();} n m.5!.  
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Utility.log(nFileLength); L#N]1#;  
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return nFileLength; -`PLewvX  
} MTn}]blH  
3o#K8EL  
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//保存下载信息（文件指针位置） SOluTFxUw  
private void write_nPos() vtRz;~,Z  
{ !4
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try{ e+y%
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output = new DataOutputStream(new FileOutputStream(tmpFile)); 5IbCE.>iU  
output.writeInt(nStartPos.length); wif1|!aL  
for(int i=0;i<nStartPos.length;i++) 5.l
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{ -5@hU8B'a  
// output.writeLong(nPos); va!fJ  
output.writeLong(fileSplitterFetch.nStartPos); B
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output.writeLong(fileSplitterFetch.nEndPos); 2>m"CG  
} ;6`7 \  
output.close(); Kn}Y7B{  
} pAyUQe;X#  
catch(IOException e){e.printStackTrace ();} Us3zvpy)o  
catch(Exception e){e.printStackTrace ();} DKG;up0  
} Zk5AZ R!|  
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//读取保存的下载信息（文件指针位置） 0<nW nD,z  
private void read_nPos() y_T%xWK5  
{ <4N E)!#  
try{ Q;kl-upn~8  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ix 5\Y  
int nCount = input.readInt(); 5Trc#i<\  
nStartPos = new long[nCount]; 7Kti&T  
nEndPos = new long[nCount]; a
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for(int i=0;i<nStartPos.length;i++) \psO$TxF=  
{ \# 1p  
nStartPos = input.readLong(); e?;  
nEndPos = input.readLong(); :d@RN+U  
} y4Nam87;/?  
input.close(); VA%4ssy  
} 3Q_)Xs r`  
catch(IOException e){e.printStackTrace ();} M+7jJ?n  
catch(Exception e){e.printStackTrace ();}
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} avUdvV-  
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private void processErrorCode(int nErrorCode) t!0 IQ9\[*  
{ |C7=$DgwY  
System.err.println("Error Code : " + nErrorCode); % xBQX  
} }1NNXxQ  
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//停止文件下载 N'?#g`*KW  
public void siteStop() K\5/||gi  
{ ge%tj O  
bStop = true; m21H68y  
for(int i=0;i<nStartPos.length;i++) }jYVB|2  
fileSplitterFetch.splitterStop(); 'fY29Xr^  
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} m4G))||9Q  
} K^%ONultv  
//负责部分文件的抓取 4"Mq]_D  
**FileSplitterFetch.java 3GXmyo:o$  
*/ aF.fd2k  
package NetFox; I%CrsEo  
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import java.io.*; SI7r`'7A'  
import java.net.*; _]us1  
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public class FileSplitterFetch extends Thread { ?qb
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String sURL; //File URL ~FnY'F<35  
long nStartPos; //File Snippet Start Position E+Dcw  
long nEndPos; //File Snippet End Position 9M@,BXOt  
int nThreadID; //Thread's ID @[]#[7  
boolean bDownOver = false; //Downing is over %4Yq (e  
boolean bStop = false; //Stop identical 2FE
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FileAccessI fileAccessI = null; //File Access interface w+hpi
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException eU\_m5xl"  
{ &PFK0tY  
this.sURL = sURL; TmJXkR.5  
this.nStartPos = nStart; fj[Kbo 7!h  
this.nEndPos = nEnd; E*QLw*H  
nThreadID = id; ;+lsNf  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 VBK|*Tl  
} yER  
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public void run() Y9B"yV  
{ l_zTpyOZ  
while(nStartPos < nEndPos && !bStop) Cw~fP[5XMF  
{ t_\&LMD  
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try{ ^t,haO4  
URL url = new URL(sURL); [iC]Wh%  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); .L.9e#?3  
httpConnection.setRequestProperty("User-Agent","NetFox"); iK8jX?  
String sProperty = "bytes="+nStartPos+"-"; Myh?=:1~(c  
httpConnection.setRequestProperty("RANGE",sProperty); f\H1$q\p\  
Utility.log(sProperty); 4j<[3~:0 o  
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InputStream input = httpConnection.getInputStream(); ]6,D9^{;  
//logResponseHead(httpConnection); 3]kN9n{  
>C`#4e?}  
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byte[] b = new byte[1024]; #j"GS/y"  
int nRead; f0*_& rP  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) =:\5*  
{ SA?1*dw)  
nStartPos += fileAccessI.write(b,0,nRead); =D)ADZ\<r  
//if(nThreadID == 1) T2|os{U  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 8( bK\-b  
} @QF;m  
ul!q)cPb{  
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Utility.log("Thread " + nThreadID + " is over!"); ^,` L!3  
bDownOver = true; `tl-] ^Y2  
//nPos = fileAccessI.write (b,0,nRead); Wl]XOUZ  
} kR{$&cE^  
catch(Exception e){e.printStackTrace ();} CW+gZ!  
} uFFC.w  
} `)Y 5L}c=  
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//打印回应的头信息 BJ{?S{"6%G  
public void logResponseHead(HttpURLConnection con) t;_1/mt  
{ XY<KLO%  
for(int i=1;;i++) o8SP#ET"n  
{ 3V<c4'O\W  
String header=con.getHeaderFieldKey(i); 2m9qg-W  
if(header!=null) 1G'pT$5&  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ,Qj\_vr@  
Utility.log(header+" : "+con.getHeaderField(header)); olK*uD'`  
else >S%}HSPKq  
break; NWj4U3x  
} !
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} ^!x qOp!  
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public void splitterStop() {*nE8+..A  
{ \\35} 9  
bStop = true; Ii>#
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} P1<McQ  
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} @.pr}S/  
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/* wV,=hMTd&\  
**FileAccess.java {vur9L  
*//文件访问(定位，写) 3M>y.MS  
package NetFox; 7<k@{xI/  
import java.io.*; 2hTsjJ!'  
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public class FileAccessI implements Serializable{ !"'@c  
#q8/=,3EG  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 l>)+HoD  
RandomAccessFile oSavedFile; %m$t'?  
long nPos; /K_*Drk>  
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public FileAccessI() throws IOException =q[ynZ8O\w  
{ 1"T&B0G3l  
this("",0); B0^:nYko  
} ~O 4@b/!4  
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public FileAccessI(String sName,long nPos) throws IOException _V` QvnT}  
{ ~L.5;8a3Pe  
oSavedFile = new RandomAccessFile(sName,"rw"); ZQmg;L&7  
this.nPos = nPos; &+/$~@OK  
oSavedFile.seek(nPos); Htep
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} 1h`#H:  
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public synchronized int write(byte[] b,int nStart,int nLen) lT'V=,Y t  
{ FQcm=d_s  
int n = -1; %t$)sg]  
try{ #:
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oSavedFile.write(b,nStart,nLen); jjg&C9w T  
n = nLen; w# ;t$qz}  
} l!IN#|{(  
catch(IOException e) Ub[UB%(T  
{ ictOCF  
e.printStackTrace (); (
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} r1sA^2g.  
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return n; j)}TZx4~  
} Y }8HJTMB  
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} $EZr@n  
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/* dz?Ey~;M  
**SiteInfoBean.java wT:mfS09N  
*/ Fh.ZsPn,m  
package NetFox; R#/0}+-M  
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public class SiteInfoBean { 'WwD$e0=  
;5}"2hU>  
5WI0[7  
private String sSiteURL; //Site's URL pwV{@h!  
private String sFilePath; //Saved File's Path gn[h:+H
&  
private String sFileName; //Saved File's Name N0fmC*1-  
private int nSplitter; //Count of Splited Downloading File >n>gX/S<C  
 j g_;pn  
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public SiteInfoBean() f
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{//nSplitter的缺省值为5 KPa&P:R3  
//default value of nSplitter is 5 wr2F]1bh@  
this("","","",5); 9>d~g
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} ;*e$k7}F  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) QC+BEN$  
{ 58Z,(4:E  
sSiteURL= sURL; _i0,?U2C  
sFilePath = sPath; OI)/J;[-e  
sFileName = sName; Xyw;Nh!!d  
this.nSplitter = nSpiltter; )(`,!s,8)  
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} @34CaZ$k  
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public String getSSiteURL() y?V#LW[^E  
{ wU5= '  
return sSiteURL; K<"Y4O#]  
} ,in"8aT}~  
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public void setSSiteURL(String value) 
(%
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{ )}T0SGY  
sSiteURL = value; 9'h4QF+Y  
} U9yR~pw  
x5!lnN,#  
J ?H|"  
public String getSFilePath() zvh&o*\2<d  
{ +q)B4A'J!  
return sFilePath; hkR Jqta)  
} bOdyrynh  
i>AKXJ+  
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public void setSFilePath(String value) YN5p@b=FX  
{ <@H=XEn  
sFilePath = value; PH]ui=  
} c"CF&vTp  
REKv&^FLN  
;NrU|g/ksX  
public String getSFileName() 5\P3JoH:Yg  
{ <Z9N}wY,8  
return sFileName; oA
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} 9y5nG  
vhu5w#]u*  
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public void setSFileName(String value)
t[?O*>  
{  FR1se  
sFileName = value; ]iVoF N}^  
} D*o[a#2_  
gAViwy9{  
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public int getNSplitter() ao.v]6a  
{ @;H1s4OZ  
return nSplitter; b>"=kN/  
} 334tg'2]  
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9='=wWW  
public void setNSplitter(int nCount) jCv%[H7  
{ .#$D\cwV  
nSplitter = nCount; 4?9cyv4H  
} ,mW-O!$3W  
} 5qx$=6PT  
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h>A}vI*:  
/* f8
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**Utility.java \3v}:E+3  
*/ 2zN%Z!a#J  
package NetFox; ?.b.mkJ  
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public class Utility { h$eVhN&Vv  
oN6 '%   

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public Utility() J`x!c9zg7  
{ t|y`Bl2  
$6p|}
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} 5(sWV:_2  
gXI8$W>  
//线程睡眠 F),wj8#~>-  
public static void sleep(int nSecond) a4iq_F#NF  
{ 2Sg,b8  
try{ wth*H$iF  
Thread.sleep(nSecond); -v7O*xm"  
} W6[# q%o  
catch(Exception e) z?i{2Fz6  
{ X6g{qzHg_  
e.printStackTrace (); 8o4?mhqV  
}
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} N3}jLl/  
X0QLT:J b  
//日志 zL,B?  
public static void log(String sMsg) (77EZ07%  
{ G`" 9/
FI7  
System.err.println(sMsg); ]aF!0Fln~  
} 2gnmk TyF  
hB)TH'R{:  
XLNR%)l  
public static void log(int sMsg) M;Dk$B{;R  
{ 8 k%!1dyMB  
System.err.println(sMsg); h (1 }g/  
} 8S_v} NUm  
} +`)4jx)r/  
6
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/* GE{u2<%@  
**TestMethod.java PLmf.hD\  
*/ *3>$f.
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package NetFox; Z-D4~
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public class TestMethod { 'U"ub2j  
}JKK"d}U  
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public TestMethod() ZdP2}w  
{ ///xx/weblogic60b2_win.exe -Ob89Z?2A  
try{ h7h[!>  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); LT ZoO9O  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Y79{v nlGk  
SiteFileFetch fileFetch = new SiteFileFetch(bean); LYv$U;*+  
fileFetch.start(); 3LaqEj  
} /?,c4K,ap  
catch(Exception e){e.printStackTrace ();} Bco_\cpt]z  
&>. w*  
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} aF~ 0\XC  
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public static void main(String[] args) 4x'N#m{p  
{ U%~L
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new TestMethod(); [N-t6Z*  
} k}yUD 0Y  
} uS%Y$v  
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