http断点续传简单实现（java)

/* dZYS5_wr  
**SiteFileFetch.java ;x7SY;0*  
*/ L_A|  
package NetFox; i&KbzOY  
import java.io.*; 6Q>w\@lF  
import java.net.*; VEpQT Qp  
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public class SiteFileFetch extends Thread { ,on
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SiteInfoBean siteInfoBean = null; //文件信息Bean cK?t]%S  
long[] nStartPos; //开始位置 U?rfE(!  
long[] nEndPos; //结束位置 lWdE^-  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Gmc"3L  
long nFileLength; //文件长度 +pV3.VMH0  
boolean bFirst = true; //是否第一次取文件 tJn2:}-s  
boolean bStop = false; //停止标志 4 IHl'*D[#  
File tmpFile; //文件下载的临时信息 z/TZOFaM  
DataOutputStream output; //输出到文件的输出流 dEL>Uly  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） E }yxF.  
public SiteFileFetch(SiteInfoBean bean) throws IOException :I7MP  
{ $ OR>JnV  
siteInfoBean = bean; 4+~+`3;~v  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); B\mdOTLQ  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); )I<.DN&  
if(tmpFile.exists ()) +Q '|->#  
{ xtnB:3  
bFirst = false; urN&."c  
read_nPos(); 7

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} '2vlfQ@8a~  
else $@NZ*m%?JQ  
{ WV6vM()#!C  
nStartPos = new long[bean.getNSplitter()]; C$hsR&  
nEndPos = new long[bean.getNSplitter()]; Ry(!<w,  
} vS0P]AUo  
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} }Yt0VtL
t  
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public void run() {P]l{W@li  
{ SAoqq  
//获得文件长度 {L+?n*;CA  
//分割文件 b)V[
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//实例FileSplitterFetch g&za/F  
//启动FileSplitterFetch线程 SUx0!_f*R  
//等待子线程返回 S*]IR"YL  
try{ mI.*b(Irp  
if(bFirst) 'Hg(N?1"  
{ JE j+>  
nFileLength = getFileSize(); fT@#S}t  
if(nFileLength == -1) %d
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{ 0#q_LB  
System.err.println("File Length is not known!"); '[HFIJ0K!  
} 5P! ZJ3C  
else if(nFileLength == -2) *n*OVI8L  
{ $nVTN.k  
System.err.println("File is not access!"); REt()$ 7~  
} 55;xAsG  
else -r,J>2`l  
{ IlE! zRA  
for(int i=0;i<nStartPos.length;i++) [$./'-I]  
{ [qy@g5`  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); dRu@5 :BP  
} YF;8il{p  
for(int i=0;i<nEndPos.length-1;i++) >GjaA1,  
{ \Lc pl-;?  
nEndPos = nStartPos[i+1]; qBpY3]/  
} eg}|%GG  
nEndPos[nEndPos.length-1] = nFileLength; KomF)KQ2r  
} o~}q@]]  
} +EpT)FJX  
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h?TE$&CL?  
//启动子线程 fb#Ob0H  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; nc31X  
for(int i=0;i<nStartPos.length;i++) |S4yol  
{ S`R ( _eD@  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 5!5P\o  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), n3)g{K^  
nStartPos,nEndPos,i); W=|B3}C?  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); -_2=NA?t  
fileSplitterFetch.start(); IUZsLNW  
} 2L,e\]2Z  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), }FFW,x  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Vb1@JC9b  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 3wr~P  
nEndPos = " + nFileLength); O<+C$J|  
// fileSplitterFetch[nPos.length-1].start(); :H?p^d e  
1LE8,Gm&  
*m|]c4  
//等待子线程结束 SKYS6b  
//int count = 0; ypml22)kz  
//是否结束while循环 bg$e80  
boolean breakWhile = false; }q~A( u  
!|`YNsR  
7{b|+0W  
while(!bStop) |d Soq~Vz  
{ ;`xu)08a  
write_nPos(); AQFx>:in  
Utility.sleep(500); ]`|bf2*eA  
breakWhile = true; \"f}Fx  
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for(int i=0;i<nStartPos.length;i++) ?$o8=h  
{ IP~g7`Y  
if(!fileSplitterFetch.bDownOver) c shZR(b  
{ 
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breakWhile = false; `yxk Sb  
break; -Y+[`0$'  
} *EDzj&  
} u{\`*dNx  
if(breakWhile) 7u!p.kN  
break; xxedezNko  
"PlM{ZI\  
]{;K|rCR-  
//count++; 5:AAqMa  
//if(count>4) nhy3E  
// siteStop(); ?C4a,%  
} aUJ&  
3"<{YEj8U  
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System.err.println("文件下载结束！"); "3!4 hiU9  
} @@! R Iq!  
catch(Exception e){e.printStackTrace ();} :qnRiK]  
} bbnAF*7s8  
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//获得文件长度 578Dl(I#)  
public long getFileSize() 6v.*%E*P  
{ TpnkJygIm  
int nFileLength = -1; VGe/;&1h  
try{ 0$
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URL url = new URL(siteInfoBean.getSSiteURL()); xo?f90+(  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); n RXf\*"3  
httpConnection.setRequestProperty("User-Agent","NetFox"); QPGssQR6  
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int responseCode=httpConnection.getResponseCode(); G*
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if(responseCode>=400) E|ZY2&J`4  
{  g\n@(T$)  
processErrorCode(responseCode); fOrqY,P'  
return -2; //-2 represent access is error =:#$_qR  
} bk"` hq  
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)L^WD$"'Q  
String sHeader; N>@AsI  
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for(int i=1;;i++)
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{ B9+oI cO  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); :y]l`Mo -  
//Utility.log(in.readLine()); PN<Y&/fB  
sHeader=httpConnection.getHeaderFieldKey(i); =<FFFoF*C_  
if(sHeader!=null) Vrz<DB^-e  
{ 0
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if(sHeader.equals("Content-Length")) >6(nW:I0y  
{ `qX'9e3VP+  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader));
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break; gpO@xk$  
} |f`!{=?  
} fFiFc^  
else G!%1<SLi.  
break; Nnx"b 5I}n  
} BYwG\2?~  
} /k7`TUK  
catch(IOException e){e.printStackTrace ();} r@wWGbQ|L  
catch(Exception e){e.printStackTrace ();} ?^k-)V  
5>/,25 99  
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Utility.log(nFileLength);  ~)WE  
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return nFileLength; 3+Xz5>"a  
} ,7tN&R_  
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//保存下载信息（文件指针位置） %vyjn
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private void write_nPos() Qp%kX@Z'  
{ ~"{Kjr#R  
try{ ]Kil/Y  
output = new DataOutputStream(new FileOutputStream(tmpFile)); HOXqIZN85  
output.writeInt(nStartPos.length); }1epn#O_4  
for(int i=0;i<nStartPos.length;i++) 8(&C0_yD  
{ 3u-j`7  
// output.writeLong(nPos); BQt!L1))  
output.writeLong(fileSplitterFetch.nStartPos); (;cbgHo%}  
output.writeLong(fileSplitterFetch.nEndPos); =3""D{l  
} ~M,n
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output.close(); g9
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} !P#lTyz  
catch(IOException e){e.printStackTrace ();} 0=7C-A1(D  
catch(Exception e){e.printStackTrace ();} N2=gSEY  
} .2G
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//读取保存的下载信息（文件指针位置） "'dt"x)  
private void read_nPos() =as]>
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{ sj
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try{ e-\J!E'1F  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); sR'rY[^/|  
int nCount = input.readInt(); ym8\q:N(R  
nStartPos = new long[nCount]; ; #e-pkV  
nEndPos = new long[nCount]; r'k-*I  
for(int i=0;i<nStartPos.length;i++) !dSY?1>U<  
{ 8_m
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nStartPos = input.readLong(); ^MDBJ0 I.  
nEndPos = input.readLong(); %e:VeP~  
} ^]AjcctGr  
input.close(); {.;MsE  
} ]%F3 xzOk  
catch(IOException e){e.printStackTrace ();} |OuZaCJG  
catch(Exception e){e.printStackTrace ();} GP[;+xMBh  
} (m~MyT#S  
ub./U@1
 
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private void processErrorCode(int nErrorCode) Nl PP|=o  
{ NuW9.6$Jrf  
System.err.println("Error Code : " + nErrorCode); n"d~UV^Uw  
} + ECV|mkk  
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}=;N3Q" #y  
//停止文件下载 s%;18V:pi  
public void siteStop() x>p=1(L  
{ C5 ^_R  
bStop = true; +2MsyA?6_  
for(int i=0;i<nStartPos.length;i++) nEyPNm)  
fileSplitterFetch.splitterStop(); NNb17=q_v  
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} pA"pt~6  
} rh/3N8[6  
//负责部分文件的抓取 ,5H$Tm,6\S  
**FileSplitterFetch.java 'xvV;bi  
*/ 2mVH*\D  
package NetFox; i#
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!5Z?D8dcx  
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import java.io.*; U7bG(?k)  
import java.net.*; el5F>)  
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public class FileSplitterFetch extends Thread { "n:L<F,g  
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String sURL; //File URL }0}J  
long nStartPos; //File Snippet Start Position 5rfGMk<  
long nEndPos; //File Snippet End Position JrYpZ.Nh  
int nThreadID; //Thread's ID ZO W{rv]  
boolean bDownOver = false; //Downing is over XZJ}nXy  
boolean bStop = false; //Stop identical ZLxe$.V_  
FileAccessI fileAccessI = null; //File Access interface hDjsGB|Fz  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException |#f P8OK  
{ Z:)\j.  
this.sURL = sURL; %[Ia#0'Y@  
this.nStartPos = nStart; C}Ewi-  
this.nEndPos = nEnd; L)HuQVc g  
nThreadID = id; L'z;*N3D  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 6EP5
n  
} G2 xYa$&][  
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public void run() jFbz:aUF  
{ t.485L%  
while(nStartPos < nEndPos && !bStop) I^0bEwqZ~  
{ u.1u/o1"  

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]%"Z[R   
try{ ~|R"GloUw  
URL url = new URL(sURL); OKxPf]~4E  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); gXc&uR0S  
httpConnection.setRequestProperty("User-Agent","NetFox"); xBR2tDi%  
String sProperty = "bytes="+nStartPos+"-"; b;Q cBGwKT  
httpConnection.setRequestProperty("RANGE",sProperty); HaJD2wvr  
Utility.log(sProperty); 80c\O-{  
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InputStream input = httpConnection.getInputStream(); I]jVnQ>&  
//logResponseHead(httpConnection); /vwGSuk._  
}NiJDs  
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byte[] b = new byte[1024]; ) l0=jb  
int nRead; FwmE1,  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) on\0i{0l8  
{ =/Vr,y$  
nStartPos += fileAccessI.write(b,0,nRead); >eWHPO  
//if(nThreadID == 1) gj$gqO`B  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); #0hX)7(j  
} //_v"dqP{)  
X;6&:%ZL@^  
4$1sBY/  
Utility.log("Thread " + nThreadID + " is over!"); [[LCEw  
bDownOver = true; xH; 4lw  
//nPos = fileAccessI.write (b,0,nRead); ){L`hQ*=w  
} cQS}pQyYN  
catch(Exception e){e.printStackTrace ();}  UTHGjE  
} V)_mo/D!D  
} /8Ca8Ju  
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//打印回应的头信息 y[.0L!C {  
public void logResponseHead(HttpURLConnection con) Cq}LKiu  
{ "<txg%j\J  
for(int i=1;;i++) .' 3;Z'%"g  
{ pU<->d;->  
String header=con.getHeaderFieldKey(i); fL' 42  
if(header!=null) y3))I\QT  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); +Y'(,J  
Utility.log(header+" : "+con.getHeaderField(header)); rF>:pS,`&  
else C4#'`8E  
break; $NT{ssh  
} Qm^N}>e  
} ERCW5b[RT  
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public void splitterStop() !!DHfAV]  
{ KokmylHu  
bStop = true; ]geO%m  
} ^W3xw[{  
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} =uMoX -  
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/* f*p=]]y  
**FileAccess.java o%RyE]pw,  
*//文件访问(定位，写) AL3zE=BL  
package NetFox; {[NBTT9&  
import java.io.*; -YJ7ne]  
OqHD=D[  
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public class FileAccessI implements Serializable{ M,3sK!`>  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 6- s/\  
RandomAccessFile oSavedFile; tb"
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long nPos; v`*!Bhc-  
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= 0
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public FileAccessI() throws IOException ./rNq!*a  
{ yAW%y  
this("",0); <x53b/ft  
} @'7'3+ c  
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public FileAccessI(String sName,long nPos) throws IOException >#)^4-e  
{ !QSL8v@c  
oSavedFile = new RandomAccessFile(sName,"rw"); Jx.Jx~  
this.nPos = nPos; "tn]s>iAd=  
oSavedFile.seek(nPos); pbl;n|  
} >E^sZmY[f-  
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%f*8JUE16  
public synchronized int write(byte[] b,int nStart,int nLen) [yW0U:m  
{ q~T*R<S  
int n = -1; !Hr~B.f7  
try{ &
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oSavedFile.write(b,nStart,nLen); HX7"w   
n = nLen; 1\$xq9  
} OtBVfA:[  
catch(IOException e) R]/3`X9!d>  
{ qa.nm4"6+  
e.printStackTrace (); +%UfnbZ  
} T9}G:6  
kL*
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return n; L(fOe3 v  
} @_J~zo  
[?Cv^t${+  
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} C-V,3}=*2  
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4%Z!*W*  
/* xVfAlN37(  
**SiteInfoBean.java h-].?X,]Q  
*/ tMR&>hM  
package NetFox; &'
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*GH`u*C_  
public class SiteInfoBean { f(6`5/C  
/q^)thJ~  
$BXZFC_1S  
private String sSiteURL; //Site's URL qRZv[T%*Q  
private String sFilePath; //Saved File's Path &5h{XSv  
private String sFileName; //Saved File's Name iqreIMWz  
private int nSplitter; //Count of Splited Downloading File idPx! fe  
A,Wwt [Qw  
;6KcX\g-  
public SiteInfoBean() "v@Y[QI  
{//nSplitter的缺省值为5 NTbmI$(  
//default value of nSplitter is 5 ]bLI!2Kr  
this("","","",5); u!hY bCB  
} gFizw:l
 
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) HkVnTC  
{ Tty_P,  
sSiteURL= sURL; MKf|(6;~  
sFilePath = sPath; O2g9<H  
sFileName = sName; ;h<(vc3@f  
this.nSplitter = nSpiltter; aMe]6cWHV>  
]V0V8fU|  
Z$LWZg  
} dWqKt0uh!  
`<2k.aW4e8  
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public String getSSiteURL() `u$  Rd  
{ H=RzY-\a%  
return sSiteURL; LeRyS]  
}
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public void setSSiteURL(String value) <:/Lap#D^  
{ &W+lwEu  
sSiteURL = value; ;)$bhNFHx  
} o&0fvCpW  
;-sZaU;  
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public String getSFilePath() E6JfSH
#  
{ =1sGT;>  
return sFilePath; 0)F.Y,L  
} ?1w{lz(P  
\kWL:uU  
iZY4+
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public void setSFilePath(String value) (+uM |a  
{ PkX4 !  
sFilePath = value; |ecK~+  
} 0,~||H{  
k
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+q n[F70}  
public String getSFileName() ,2oFt\`.r  
{ 3r^Ls[ey  
return sFileName; S!WG|75B  
} C0C2]xx{  
bpP-wA^Hd  
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public void setSFileName(String value) dhrh "x_?:  
{ b3.  
sFileName = value; [l44,!Z
&  
} E$SYXe[,  
c"KN;9c,  
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public int getNSplitter() t2x2_;a  
{ zVt1Ta:j  
return nSplitter; lCafsIB  
} `A\,$(q+  
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public void setNSplitter(int nCount) $40G$w  
{ 'h}(>%  
nSplitter = nCount; aa2 vk)~  
} o8_))  
} W(5XcP(  
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C)UL{n  
/* OSoIH`tA  
**Utility.java LV2#w_^I  
*/ |7%has3"  
package NetFox; [}$jO,H5r  
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ca=sc[ $+  
public class Utility { R?{f:,3R  
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public Utility() [#@\A]LO  
{ i+qtL3  
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} YCl&}/.pA  
E)3Ah!  
//线程睡眠 ZLDO&}  
public static void sleep(int nSecond) "DO|B=EejP  
{ |N5r_V  
try{ ~=GwNo_  
Thread.sleep(nSecond); UuS6y9@v  
} dNu?O>=  
catch(Exception e) joz0D!-"#  
{ 2dsXG$-W2  
e.printStackTrace (); =jEVHIYt  
} ^[x6p}$  
} KvjsibI/Y  
S>Z07d6&  
//日志 g^l~AR  
public static void log(String sMsg) aD^jlt  
{ LZtO Q__B)  
System.err.println(sMsg); *iX PG9XZ  
} lVv'_9yg  
lvAKL>qX  
qnb#~=x^  
public static void log(int sMsg) .oS[ DTn5S  
{ &w!(.uDO  
System.err.println(sMsg); 8]K+,0m6  
} )%q!XM  
} FMX^k  

,ZI#p6  
|A.nP9hW  
/* dVMduo  
**TestMethod.java S awf]/  
*/ :F8h}\a*  
package NetFox; mxnu\@}(  
dQn,0  
=AcK9?%5  
public class TestMethod { }}qY,@eeX  
2BKiA[ ;;  
kyi"U A82  
public TestMethod() 1l5'N=hL  
{ ///xx/weblogic60b2_win.exe J#IVu?B
  
try{ ;il+C!6zpf  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 00B,1Q HP  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 82)%`$yZw[  
SiteFileFetch fileFetch = new SiteFileFetch(bean); e'yw
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fileFetch.start(); g@'2 :'\  
} C2CR#b=)i  
catch(Exception e){e.printStackTrace ();} {[4.<|2
6  
Up1n0
  
llN/  
} x4i&;SP0  
\kZ@2.pN  
$."DOZQ3U  
public static void main(String[] args)

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{ n8E3w:A-  
new TestMethod(); +B[XTn,Cru  
} Q#F9&{'l  
} Aj8zFt]  
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