http断点续传简单实现（java)

/* Y[K*57fs  
**SiteFileFetch.java _q{c##Kf  
*/ =y
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package NetFox; j"'(sW-  
import java.io.*; p~,]*y:XT  
import java.net.*; Gch[Otq]%  
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public class SiteFileFetch extends Thread { U}PiY"S<  
< !dqTJos  
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SiteInfoBean siteInfoBean = null; //文件信息Bean J_v$YwE  
long[] nStartPos; //开始位置 }XSfst5-H  
long[] nEndPos; //结束位置 }C>{uXv  
FileSplitterFetch[] fileSplitterFetch; //子线程对象  )8UWhl=  
long nFileLength; //文件长度 Oms. e  
boolean bFirst = true; //是否第一次取文件 t{WzKy  
boolean bStop = false; //停止标志 Tny%7xSx1  
File tmpFile; //文件下载的临时信息 *]VFvh  
DataOutputStream output; //输出到文件的输出流 lAJxr8 .  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） :E@3Vl#U  
public SiteFileFetch(SiteInfoBean bean) throws IOException g;8jK8Kh  
{ x\s|n{  
siteInfoBean = bean; /i-J&*6_  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); T|dY 2  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); D0#x Lh  
if(tmpFile.exists ()) isZAoYVu  
{ U9A~9"O  
bFirst = false; F>-B3x  
read_nPos(); r.>].~}4  
} kLni{IYN7  
else lobGj8uxq  
{ N.]qU d  
nStartPos = new long[bean.getNSplitter()]; N%"Y  
nEndPos = new long[bean.getNSplitter()]; }`v~I4i  
} fbL\?S,w  
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} , 'ZD=4_  
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public void run() o;=l^-  
{ ]zQo>W$  
//获得文件长度 Pp`*]Ib  
//分割文件 #z2rzM@/:  
//实例FileSplitterFetch IuOgxm~Y  
//启动FileSplitterFetch线程 bLQ ^fH4ww  
//等待子线程返回 00SbH$SU  
try{ 1}:bqI.<W  
if(bFirst) _:-ha?W$;y  
{ LX@/RAd vz  
nFileLength = getFileSize(); '`XX "_k3  
if(nFileLength == -1) <X7FMNr[  
{ ,>:;#2+og  
System.err.println("File Length is not known!"); Sk:ws&D1u  
} t0nI('LX,  
else if(nFileLength == -2) NyVnA  
{ y
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System.err.println("File is not access!"); Sz^5b!  
} ZP;j9T!  
else mN>h5G>a  
{ 1e>s{  
for(int i=0;i<nStartPos.length;i++) =7C%P%yt  
{ 8}FzZ?DRy  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Bnb#{tL  
} u)V#S:9]  
for(int i=0;i<nEndPos.length-1;i++) 9

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{ &p}$J)q  
nEndPos = nStartPos[i+1]; n%k!vJ)]  
} %c [F;ug  
nEndPos[nEndPos.length-1] = nFileLength; BwBm[jtP  
} cu%
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} @*qz(h]\  
r; xLP  
l"!Ko G7  
//启动子线程 zj/!In  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; EC\yzH*X  
for(int i=0;i<nStartPos.length;i++) 59!Fkd3  
{ 5Pd"h S  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), g+ MdHn[  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), qWx][D"  
nStartPos,nEndPos,i); |{@8m9JR  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); _x?
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fileSplitterFetch.start(); :J:,m  
}  k0  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), K\$J4~EtG  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); .'rW.'Ft  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", {fEwA8Ir  
nEndPos = " + nFileLength); u&9 r2R959  
// fileSplitterFetch[nPos.length-1].start(); ]miy/V }5  
<]T`3W9  
EM/@T}  
//等待子线程结束 \MmI`$  
//int count = 0; GQl$yZaK{  
//是否结束while循环 jU3Z*Z)zN  
boolean breakWhile = false; r.T<j.\  
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V~hlq$jn<Y  
while(!bStop) WJ d%2pO]  
{ 0k'e:AjP  
write_nPos(); qt3PXqR7:  
Utility.sleep(500); Hw|AA?,0-  
breakWhile = true; BA:
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p<&Xd}]"^W  
UTSL  
for(int i=0;i<nStartPos.length;i++) _9?I A  
{ rC7``#5  
if(!fileSplitterFetch.bDownOver) Q3 eM2i8Y  
{ r 3M1e+'fc  
breakWhile = false; `$~RxzZ g  
break; Sje wuIi1  
} ^47PLLRP  
} 8srBHslI  
if(breakWhile) [ G e=kFB  
break; oP2fX_v1x  
$Y9jrR'w  
%&Fk4Z}M  
//count++; %',F  
//if(count>4) cDoo
*  
// siteStop(); Maqf[ Vky  
} 7nVRn9Hn  
{66fG53x  
zi'Jr)n  
System.err.println("文件下载结束！"); 97,rE$bC  
} m$LVCB  
catch(Exception e){e.printStackTrace ();} /R LI,.%  
} ,=~z6[  
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{u\%hpD_  
//获得文件长度 axk"^gps  
public long getFileSize() 1 Vy,&[c~"  
{ '>k{tPi.  
int nFileLength = -1; Dw2Q 'E  
try{ npD
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URL url = new URL(siteInfoBean.getSSiteURL()); zD)pF1,7:8  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); DOQc"+  
httpConnection.setRequestProperty("User-Agent","NetFox"); !>(RK"KWq]  
OI0B:()  
@+Y8*Rj\3  
int responseCode=httpConnection.getResponseCode(); =9G;PVk|  
if(responseCode>=400) 0fs$#j  
{ @cq`:_.[  
processErrorCode(responseCode); }4>JO""  
return -2; //-2 represent access is error Zw] ?.  
} %>WbmpIyc  
`*\{.;,]#  
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String sHeader; ~/IexQB&  
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for(int i=1;;i++) (D{Ys'{q  
{ @("}]/O V:  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); \m@Y WO?L  
//Utility.log(in.readLine()); l#@&~f[  
sHeader=httpConnection.getHeaderFieldKey(i); {BO
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if(sHeader!=null) z8Q"%
@  
{ 2D([Z-<i  
if(sHeader.equals("Content-Length")) ~E=\t9r  
{ m]IysyFFK  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); (Btv ClZ  
break;
[}3cDR  
} *+8%kn`c  
} ^p_u.P  
else ^C9x.4I$)  
break; g]`bnZ7  
} $Kq<W{H3ut  
} &.*uc|{  
catch(IOException e){e.printStackTrace ();} 4w{-'M.B  
catch(Exception e){e.printStackTrace ();} M^H90GN)X  
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MB*u-N0v  
Utility.log(nFileLength); kb|eQtH  
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return nFileLength; *`KrVu 6s  
} ygvzdYd  
!*P&Eat  
9NWloK6bT  
//保存下载信息（文件指针位置） WL\^F#:  
private void write_nPos()  q{X T  
{ n9fk,3  
try{ Q
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output = new DataOutputStream(new FileOutputStream(tmpFile)); 7Qh_8
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output.writeInt(nStartPos.length); r]t )x*  
for(int i=0;i<nStartPos.length;i++) F^'v{@C  
{ ?Bu}.0ku-$  
// output.writeLong(nPos); tF`MT%{Va  
output.writeLong(fileSplitterFetch.nStartPos); m.V,I}J.q  
output.writeLong(fileSplitterFetch.nEndPos); a{_ KSg  
} O|UxFnB}  
output.close(); 8U^D(jrz  
} IT1PPm  
catch(IOException e){e.printStackTrace ();} "2mFC!  
catch(Exception e){e.printStackTrace ();} ozxYH],  
} 9bEM#Hj  
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;i9>}]6  
//读取保存的下载信息（文件指针位置）  5T/J%  
private void read_nPos() Wg(bD,  
{ aRKv+{K  
try{ a`38db(z  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); XOxB (0@  
int nCount = input.readInt(); ih!~G5Xi9i  
nStartPos = new long[nCount]; h^d\xn9GT#  
nEndPos = new long[nCount]; &Y=.D:z<  
for(int i=0;i<nStartPos.length;i++)
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{ &9@gm--b:  
nStartPos = input.readLong(); SJOmeN}4)  
nEndPos = input.readLong(); zS?n>ElI  
} .d e  
input.close(); QxA0I+i  
} R|H[lbw  
catch(IOException e){e.printStackTrace ();} I)rGOda{  
catch(Exception e){e.printStackTrace ();} 3/l\ <{  
} Lb^(E-  
wH#-mu#Yl<  
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private void processErrorCode(int nErrorCode) 5=m3J!?  
{ + lP5XY{  
System.err.println("Error Code : " + nErrorCode); )ZN(2z  
} v#-E~;CcC  
<g*.p@o  
KCl &H  
//停止文件下载 61L7 -~  
public void siteStop() {f&NStiB  
{ QP+c?ct}hF  
bStop = true; "NJ,0A  
for(int i=0;i<nStartPos.length;i++) t18UDR{  
fileSplitterFetch.splitterStop(); 6hLNJ  
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xkF$D:sP  
} >H)^6sJ;%b  
} <8g=BWA  
//负责部分文件的抓取 \ibCR~
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**FileSplitterFetch.java jk K#e$7  
*/ yLjV[qP  
package NetFox; Akv(} !g  
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import java.io.*; oG+K '(B
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import java.net.*; 5ze`IY  
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public class FileSplitterFetch extends Thread { F5<"ktnI  
Ko1AaX(I'+  
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String sURL; //File URL !S~,>,y
d  
long nStartPos; //File Snippet Start Position ~!8%_J_  
long nEndPos; //File Snippet End Position n^* >a  
int nThreadID; //Thread's ID @*CAn(@#N  
boolean bDownOver = false; //Downing is over q,<n,0)K  
boolean bStop = false; //Stop identical \?bwm&6+r  
FileAccessI fileAccessI = null; //File Access interface 3C>2x(]M  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException <{$ev&bQ  
{ :*mA,2s  
this.sURL = sURL; &eThH,w$2  
this.nStartPos = nStart; ~bQFk?ZN+  
this.nEndPos = nEnd; 2(c<U6#C'l  
nThreadID = id; c'4>D,?1  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 @?<N +qdH>  
} xaGVu0q  
xB?S#5G}  

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public void run() qWRNHUd  
{ ^tm++  
while(nStartPos < nEndPos && !bStop) fOqS|1rC  
{ Ft3N#!ubl  
/Nj:!! AN  
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try{ ^4u3Q  
URL url = new URL(sURL); ?;0nJf  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); .
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httpConnection.setRequestProperty("User-Agent","NetFox"); OmTZ-*N  
String sProperty = "bytes="+nStartPos+"-"; d8Q_6(Ar|  
httpConnection.setRequestProperty("RANGE",sProperty); l|@/?GaH  
Utility.log(sProperty); GW>7R6i  
~pd1)  
;kyL>mV{  
InputStream input = httpConnection.getInputStream(); xJ[k#?T'  
//logResponseHead(httpConnection); ^DW#  
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/%ODJ1M  
byte[] b = new byte[1024]; rZ8Y=) e  
int nRead; Q.pEUDq/  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) M5cOz|j/*R  
{ *!r\GGb  
nStartPos += fileAccessI.write(b,0,nRead); .yK\
&q[<  
//if(nThreadID == 1) 6mI_Q2  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); &J6o$i  
} F(KH-  
j$|Yd=  
[5RFQ!  
Utility.log("Thread " + nThreadID + " is over!"); we:5gK&  
bDownOver = true; ? !oVf>  
//nPos = fileAccessI.write (b,0,nRead); /+<%,c$n  
} 8}"f|6Wm  
catch(Exception e){e.printStackTrace ();} fncwe ';?  
} 7/^TwNsv  
} yNLa3mW  
MuFU?3ovG*  
 z~}StCH(  
//打印回应的头信息 ZyS;+"
 
public void logResponseHead(HttpURLConnection con) 7?Qt2tr  
{ h87L8qh9  
for(int i=1;;i++) h-2E9Z  
{ _M"$5 T  
String header=con.getHeaderFieldKey(i); 2#n$x*CY  
if(header!=null) ZHiICh|et%  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); /v bO/Mr  
Utility.log(header+" : "+con.getHeaderField(header)); uwH
)/BW)[  
else r_g\_y7ua  
break; _Y ><ih  
} [KimY  
} FQ9csUjpB  
Y&05 *
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#)PGQ)(  
public void splitterStop() YzhN|!;!k  
{ $^NWzc  
bStop = true; O&?CoA?  
} !7ZfT?&  
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} ~kj(s>xP  
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/* Za:BJ:  
**FileAccess.java YAC zznN  
*//文件访问(定位，写) i3kI2\bd/  
package NetFox; !{]v='   
import java.io.*; mk`cyN>m  
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public class FileAccessI implements Serializable{ Zs$RKJ7  
xwH|ryfs,Z  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 <1g1hqK3  
RandomAccessFile oSavedFile; %*Z2Gef?H  
long nPos; RkH oT^  
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public FileAccessI() throws IOException w`#0 Y9O  
{ q=0{E0@9({  
this("",0); f/[?5M[  
} 8apKp?~yW  
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public FileAccessI(String sName,long nPos) throws IOException zS"zb  
{ Lc:SqF  
oSavedFile = new RandomAccessFile(sName,"rw"); %qjyk=z+Z  
this.nPos = nPos; seV;f^-hR  
oSavedFile.seek(nPos); )|^<woli,  
} 5wFS.!xD  
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|8U7C\S[  
public synchronized int write(byte[] b,int nStart,int nLen) dt0E0i  
{ fJ"~XTN}T  
int n = -1; L+ETMk0  
try{ gZ>orZL'  
oSavedFile.write(b,nStart,nLen); w4MMo  
n = nLen; & Dl
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} J
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catch(IOException e) ND9>`I5  
{ rIWN!@.J  
e.printStackTrace (); Ty4%du6?d  
} ' /<b[  
*(q8?x0>  
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return n; nTy,Jml  
} b= ec?n #7  
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} .L{+O6*c  
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/* q
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**SiteInfoBean.java k+GK1Yl  
*/ 2#A9D.- h  
package NetFox; ,lS-
;.  
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public class SiteInfoBean { +ET  
)qP{X,Uf  
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private String sSiteURL; //Site's URL Q;,3W+(  
private String sFilePath; //Saved File's Path !#gE'(J;c  
private String sFileName; //Saved File's Name
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private int nSplitter; //Count of Splited Downloading File M"l rwun^  
RTA=|q  
wp GnS  
public SiteInfoBean() p6
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{//nSplitter的缺省值为5 ${6'  
//default value of nSplitter is 5 HYnqx>L ~  
this("","","",5); ,u^0V"hJ  
} (BQ3M-  
:.<TWBoV  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) r<"/P`r  
{ ~teW1lMu(  
sSiteURL= sURL; EAE\Xv  
sFilePath = sPath; TaO;r=2  
sFileName = sName; vFC=qLz:  
this.nSplitter = nSpiltter; FY}*Z=D%  
5@A=, GPUn  
 CF92AY
 
} VgTI2  
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public String getSSiteURL() ZDJWd
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{ tsVhPo]e0  
return sSiteURL; >:E-^t%  
} W2Z]?l;vQQ  
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public void setSSiteURL(String value) j|dzd<kE6  
{ '[8
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sSiteURL = value; k0Yixa  
} b/Q"j3
 
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public String getSFilePath() \ySc uT  
{ T-i]O*u  
return sFilePath; <r3n?w8  
}
:"IH*7xp  
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q#-H+7 5  
public void setSFilePath(String value) LfM(DK  
{ A|Gqjy^;@  
sFilePath = value; 5D*V%v  
} 1*b%C
"C  
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gg_(%.>  
public String getSFileName() "T=LHjE  
{ B*N8:u  
return sFileName; ) <~7<.0  
} (9|K}IM:  
[_1G\z_iE  
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public void setSFileName(String value) rdg1<Z  
{ h(sKGCG
 
sFileName = value; S-|$sV^cG  
} ^o:5B%}#[  
s:P-F0q!&  
DLZ63'  
public int getNSplitter() W>Kn*Dy8~  
{ h,G$e|[?  
return nSplitter; ElxbHQj6  
} |lY8u~%  
rtz(Jt{<  
(@9}FHJzi  
public void setNSplitter(int nCount) GvY8O|a  
{ [MG:Ym).2`  
nSplitter = nCount; p9J(,}  
} 4esf&-gG  
} H]\H'r"  
_G`aI*rKsy  
&bb*
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/* 5Jp>2d  
**Utility.java \)hmg  
*/ wqsnyP/m  
package NetFox; 'yqp  
r38CPdE;}  
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public class Utility { S5vJC-"  
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public Utility() Ghz)=3  
{ UNJ|J$T]  
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[@)|j=:i:  
} $xqphhBg  
l6RJour  
//线程睡眠 v,s]:9f`\>  
public static void sleep(int nSecond) 3ul  
{ *|cvx:GO  
try{ -95`.o  
Thread.sleep(nSecond); KW)yTE<  
} /<5/gV 1Q  
catch(Exception e) 6Dch+*4*@  
{ k0,~wn\#h  
e.printStackTrace (); /[mCK3_  
} ) ":~`Z*@  
} 7dLPy[8";t  
_g
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//日志 "8N]1q:$4  
public static void log(String sMsg) 6@ + >UZr\  
{ VFyt9:
a  
System.err.println(sMsg); A%Ao yy4E  
} jtA Yp3M-$  
mu*wX'.'  
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public static void log(int sMsg) #3.\}d)  
{ 3Z`oI#-x  
System.err.println(sMsg); lA{Sr0fTP  
} g{&ux k);  
} 3)=$BSC%  
^LZU><{';  
4ed( DSN  
/* HYtkSsXLN  
**TestMethod.java ^ c:(HUo#  
*/ #<)u%)`  
package NetFox; WL>"hkx  
>%xJ
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G.9?ApG9  
public class TestMethod { !X8:#a(  
nU/v(lN  
|d8/ZD  
public TestMethod() xl s_g/Q  
{ ///xx/weblogic60b2_win.exe 8c#u"qF  
try{ b"p,~{  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); zK33.HY  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); D=e&"V a  
SiteFileFetch fileFetch = new SiteFileFetch(bean); A|jaWZM-  
fileFetch.start(); 1Ocyrn  
} H!,#Z7s  
catch(Exception e){e.printStackTrace ();} m"`&FA  
#lNi\Lw+j  
iN_G|w[d  
} !J.qH%S5  
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public static void main(String[] args) B;L~hM  
{ \9!W^i[+  
new TestMethod(); ;g*ab
 
} POdG1;)  
} 5PG%)xff*  
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