http断点续传简单实现（java)

/* hLb;5u&!kW  
**SiteFileFetch.java aO8
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*/ ]y3pE}R  
package NetFox; #TMm#?lC  
import java.io.*; 9=t#5J#O  
import java.net.*; ,CJAzGBS  
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[YC=d1F5  
public class SiteFileFetch extends Thread { qbS'|--wH  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 9[cp7
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long[] nStartPos; //开始位置 uYFMv=>j  
long[] nEndPos; //结束位置 
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FileSplitterFetch[] fileSplitterFetch; //子线程对象 [Q4_WKI0T  
long nFileLength; //文件长度 wYZT D*A2h  
boolean bFirst = true; //是否第一次取文件 C=fsJ=a5;  
boolean bStop = false; //停止标志 L
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File tmpFile; //文件下载的临时信息 FH)t:!#  
DataOutputStream output; //输出到文件的输出流 CzYGq  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） $o]r]#B+  
public SiteFileFetch(SiteInfoBean bean) throws IOException :w@F?:C  
{ ^vJ"-{  
siteInfoBean = bean; 7OB%A&  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); v#  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info");  }10\K  
if(tmpFile.exists ()) ,Pn-ZF  
{ (2U
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bFirst = false; 4L8z>9
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read_nPos(); mDE'<c`b4  
} "r u]?{v  
else EQ4#fAM)  
{ 'eDJ@4Xm  
nStartPos = new long[bean.getNSplitter()]; 9]"S:{KSCn  
nEndPos = new long[bean.getNSplitter()]; ac9q
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} M70c{s`w5  
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vt//)*(.$  
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} K
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public void run() {@?G 9UypA  
{ #Mh{<gk%ax  
//获得文件长度 X*i/A<Y`=  
//分割文件 / /'Tck  
//实例FileSplitterFetch dd]?9  
//启动FileSplitterFetch线程 {jjSJIV1  
//等待子线程返回 >*IN  
try{ rah,dVE]  
if(bFirst) 7W"/N#G  
{ x<)G( Xe*  
nFileLength = getFileSize(); }^9]jSq5  
if(nFileLength == -1) l71gf.4g  
{ BT]ua]T+  
System.err.println("File Length is not known!"); 0
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} !=3Rg-'d1  
else if(nFileLength == -2) Guh%eR'Wt  
{ rz6uDJ"  
System.err.println("File is not access!");  {@gAv!  
} \#CM <%  
else &uv0G'"\  
{ U[R@x`  
for(int i=0;i<nStartPos.length;i++) 2R]&v;A  
{ J{`eLmTu  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Z`Pd2VRp  
} 6SVqRD<`  
for(int i=0;i<nEndPos.length-1;i++) j Fma|y  
{ EM@;3.IO  
nEndPos = nStartPos[i+1]; ibJHU@l  
} 2#3^skj  
nEndPos[nEndPos.length-1] = nFileLength; v!H:^!z  
} #Z\
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} Cp#)wxi6[y  
FXV`9uq}Z  
$J.T$0pFa  
//启动子线程 nU(DYHc+l  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; I^D0<lHl~  
for(int i=0;i<nStartPos.length;i++) M`vyTuO3SO  
{ dt_e  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), m 41t(i  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 'Hw4j:pS  
nStartPos,nEndPos,i); nBN&.+3t  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); q@n^ZzTx  
fileSplitterFetch.start(); AVG>_$<  
} `2`fiKm  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), +
Ng0WS_0  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ahJ1n<  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", B<7/,d'  
nEndPos = " + nFileLength); =oX>Ph+ P  
// fileSplitterFetch[nPos.length-1].start(); >E:<E'L  
eWvo,

4  
@m~RtC-Q  
//等待子线程结束 ?7jg(`Yh  
//int count = 0; !"Q}R p  
//是否结束while循环 _n"Ae?
TP  
boolean breakWhile = false; &.Q8Mi aT  
ymWgf6r<  
fQ+\;iAU  
while(!bStop) cX:HD+wO  
{ u=r`t(Z1H  
write_nPos(); [Il~K  
Utility.sleep(500); -kpswP  
breakWhile = true; ""{|3XJe  
)zq.4  
y{d^?(-  
for(int i=0;i<nStartPos.length;i++) ,Q/Ac{C  
{ W2Luz;(U  
if(!fileSplitterFetch.bDownOver) G^wtE90  
{ @ {#mpDX  
breakWhile = false; V-!"%fO.s  
break; Kmz7c|  
} 4=Gph  
} uS+k^ #  
if(breakWhile) l&$$w!n0w  
break; T[?6[,.  
PUdM[-zjh  
;n6b%,s  
//count++; -x`G2i  
//if(count>4) 1mH%H*#  
// siteStop(); R}:KE&tq  
} uj|BQ`k  
~u87H?  
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System.err.println("文件下载结束！"); -n5 B)uw=  
} wGsRS[  
catch(Exception e){e.printStackTrace ();} Z5(enTy-  
} nkDy!"K  
|3hY6aty  
{g6Qv-  
//获得文件长度 ;AJTytE>%  
public long getFileSize() Ucdj4[/,h  
{ T]T;$  
int nFileLength = -1; >dzsQ^Nj  
try{ E7zm{BX]  
URL url = new URL(siteInfoBean.getSSiteURL()); (08I  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ,#]t$mzbQ(  
httpConnection.setRequestProperty("User-Agent","NetFox"); x3pND  
?7MqeR4/E  
=Gk/k}1  
int responseCode=httpConnection.getResponseCode(); \5)htL1F  
if(responseCode>=400) :_kAl? eJ  
{ J;$N{"M  
processErrorCode(responseCode); ,`A?!.K$  
return -2; //-2 represent access is error " =] -%B  
} *&Lq!rFS  
Cx_Q:6T  
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String sHeader; o4b~4h{%  
]aryV?!6  
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for(int i=1;;i++) C0*@0~8$9  
{ 6t'l(E +  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); f~{}zGTM:  
//Utility.log(in.readLine()); {yA$V0`N{  
sHeader=httpConnection.getHeaderFieldKey(i); Q&'}BeUbm  
if(sHeader!=null) X+k}2HvNG  
{ 8ho[I]  
if(sHeader.equals("Content-Length")) qU6nJi+-I  
{ US [dkbKo  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Gfp1mev  
break; +;}#B~:  
} L I>(RMv  
} JPn$FQD  
else k>jbcSY(z<  
break; W5L iXM  
} $_H`   
} I zbU)ud  
catch(IOException e){e.printStackTrace ();} e
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catch(Exception e){e.printStackTrace ();} `#-P[q<v-  
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Utility.log(nFileLength); 6]
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=qy=-j]  
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return nFileLength; {O<l[|Ip  
} r7]zQIE  
c#IYFTz  
}N0Qm[
R  
//保存下载信息（文件指针位置） PQKaqv}N  
private void write_nPos() Cxod[$8  
{ K$K^=>I"o  
try{ @H>@[+S#  
output = new DataOutputStream(new FileOutputStream(tmpFile)); K_?W\Yg   
output.writeInt(nStartPos.length); >odbOi+X  
for(int i=0;i<nStartPos.length;i++) me6OPc;:!  
{ cRd0S*QN2  
// output.writeLong(nPos); ps .]N   
output.writeLong(fileSplitterFetch.nStartPos); 'J&f%kx"  
output.writeLong(fileSplitterFetch.nEndPos); v[plT2"s  
} :0)3K7Q  
output.close(); {j5e9pg1L|  
} cKb)VG^  
catch(IOException e){e.printStackTrace ();} ]ul$*  
catch(Exception e){e.printStackTrace ();} x_Jwd^`t!  
} R" )bDy?  
%CUGm$nH  
'I;!pUfVp  
//读取保存的下载信息（文件指针位置） ;w|b0V6  
private void read_nPos() ]lw|pvtd  
{ Hn>B!Bm*  
try{ r
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DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 7QKr_  
int nCount = input.readInt(); K{b(J Nd  
nStartPos = new long[nCount]; &[NG]V!Oc  
nEndPos = new long[nCount]; 8t@p@Td|  
for(int i=0;i<nStartPos.length;i++) ZCKka0*
 
{ bl_H4  
nStartPos = input.readLong(); cLPkK3O\=  
nEndPos = input.readLong(); K
7Rpr.p  
} >9RD_QG7  
input.close(); bY}eUL2i4  
} 'XY`(3q  
catch(IOException e){e.printStackTrace ();} YEkh3FrbwH  
catch(Exception e){e.printStackTrace ();} .<tquswg  
} W^3uEm&l!)  
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private void processErrorCode(int nErrorCode) r]
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{ JpsPNa  
System.err.println("Error Code : " + nErrorCode); O+}qQNe<  
} _k8A$s<d  
ebPgYxVZR  
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//停止文件下载 yV_4?nh  
public void siteStop() AU-n&uX  
{ "qc6=:y}  
bStop = true; d*)CT?d
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for(int i=0;i<nStartPos.length;i++) nhIa175'  
fileSplitterFetch.splitterStop(); kJWN.  
%dQxJMwj  
+f*OliMD  
} 5~mh'<:  
} Z2im@c67{  
//负责部分文件的抓取 ,`ZYvF^%  
**FileSplitterFetch.java +)2s-A f-  
*/ ^Y-]*8;]  
package NetFox; T\w?$ s  
kP/M<X"  
v1a6?-  
import java.io.*; asY[8r?U  
import java.net.*; \(t@1]&jw  
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CR6R?R3b  
public class FileSplitterFetch extends Thread { /dv<qp  
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vjjSKP6B  
String sURL; //File URL ,+~rd4a  
long nStartPos; //File Snippet Start Position pb#?l6x$+  
long nEndPos; //File Snippet End Position r5!/[_l  
int nThreadID; //Thread's ID }$bF 5&  
boolean bDownOver = false; //Downing is over <dW]\h?)  
boolean bStop = false; //Stop identical %W@v2  
FileAccessI fileAccessI = null; //File Access interface wywQ<n  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException sP^R/z|Y  
{ E;<l(.Ar  
this.sURL = sURL;
ox+ 3U  
this.nStartPos = nStart; <7-J0btV  
this.nEndPos = nEnd; 0P\$2lk  
nThreadID = id; Z*-g[8FO  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 S[7WW$lF  
} TDd{.8qf  
6xD#?  
s}N#n(  
public void run() * S=\
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{ &3yD_P_3  
while(nStartPos < nEndPos && !bStop) %/9 EORdeH  
{ kWdi595  
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qhT@;W/X  
try{ 7O,U?p  
URL url = new URL(sURL); !9xp c
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ~ o1x;Y6  
httpConnection.setRequestProperty("User-Agent","NetFox"); i\W/C  
String sProperty = "bytes="+nStartPos+"-"; ` AY_2>7  
httpConnection.setRequestProperty("RANGE",sProperty); -eX5z  
Utility.log(sProperty); C+|b1/N-  
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y#XbJuN/  
InputStream input = httpConnection.getInputStream(); }#X8@  
//logResponseHead(httpConnection); It{;SKeo  
 A^p[52`  
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byte[] b = new byte[1024]; qL,tYJ<m%  
int nRead; Y5F]:gs@  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) :]J Ye*  
{ sP ls zC[  
nStartPos += fileAccessI.write(b,0,nRead); +|tC'gCnV  
//if(nThreadID == 1) N5 $c]E  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); }[M`uZ  
} :UQTEdc{  
RIIitgV_  
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Utility.log("Thread " + nThreadID + " is over!"); ATR!7i\|  
bDownOver = true; +wkjS r`e  
//nPos = fileAccessI.write (b,0,nRead); +zy=50,   
} /{|fyKo\?  
catch(Exception e){e.printStackTrace ();}
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} o`Ta("9^  
} rD*sl}  
.w]GWL  
XP@1~$  
//打印回应的头信息 8stwg'  
public void logResponseHead(HttpURLConnection con) =9j8cC5y  
{ F+@5C:<?  
for(int i=1;;i++) t*?0D\b 2  
{ %JLk$sP9y`  
String header=con.getHeaderFieldKey(i); y
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if(header!=null) !%c'$f/  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); .-<k>9S7_  
Utility.log(header+" : "+con.getHeaderField(header)); IKi5 v~bE  
else B9wPU1  
break; 8cA~R-  
} X=>=5'  
} {RF-sqce  
&B|D;|7H  
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public void splitterStop() $]8
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{ $jg*pmR-  
bStop = true; ;INW`b~  
} AZmb!}m+d  
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} 2Y7)WPn  
+=:#wzK@  
# 0Lf<NZ  
/* ;s52{>&F]  
**FileAccess.java 9k6r_G"  
*//文件访问(定位，写) ^.>jGI%rB  
package NetFox; i@4~.iZ8  
import java.io.*; ?2oHZ%G  
E<c9#I=  
Pcw6!xH  
public class FileAccessI implements Serializable{ LGl2$#x  
A*um{E+  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 kS!viJwtT  
RandomAccessFile oSavedFile; LA`*_|}qcR  
long nPos; ak;*W  
Ovj^IjG-`  
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public FileAccessI() throws IOException !=N"vD*  
{ fXcm|U,ho  
this("",0); Lliqj1&  
} N"3b{Qio  
B` k\EL'  
HB7;0yt`:  
public FileAccessI(String sName,long nPos) throws IOException 1n@8Kv  
{ PnoPbk[<  
oSavedFile = new RandomAccessFile(sName,"rw"); Yc'kvj)_M  
this.nPos = nPos; yfm^?G|sW  
oSavedFile.seek(nPos); n-%s8aaVf  
} APO>y  
&0`) Q
 
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public synchronized int write(byte[] b,int nStart,int nLen) ^g`&7tX  
{ %wSj%>&-R  
int n = -1; cra+T+|>Kc  
try{ U\R}`l  
oSavedFile.write(b,nStart,nLen); kP?KXT3y  
n = nLen; et }T%~T  
} GxKqD;;u?=  
catch(IOException e) R[;zX(y  
{ V#`fs|e;y  
e.printStackTrace (); sxt-Vs7+6  
} *;Ed*ibf  
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return n; /IM#.v  
} ,j$Vvz  
)'4k|@8|  
#/Eb*2C`b  
} W]5USFan  
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8A+SjJ4$  
/* m`FNIY  
**SiteInfoBean.java UNkCL4N  
*/ Ba/Yl  
package NetFox; u,w:SM@*(  
`4~H/'%QB  
n;:rf7hGY  
public class SiteInfoBean { - h9?1vc7  
wy}k1E'M  

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private String sSiteURL; //Site's URL 9t#S= DP  
private String sFilePath; //Saved File's Path 2!$gyu6bpG  
private String sFileName; //Saved File's Name yd?x=|  
private int nSplitter; //Count of Splited Downloading File &w1P\4?G  
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public SiteInfoBean() ^)W[l!!<)  
{//nSplitter的缺省值为5 ()3
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//default value of nSplitter is 5 iX4Iu3  
this("","","",5);  z~>pVs
  
} INyk3`FT  
sn?]n~z  
_`pD`7:aI^  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) \} ^E`b  
{ [mPjP%{=@  
sSiteURL= sURL; @!8ZPiW<  
sFilePath = sPath; d:i;z9b@to  
sFileName = sName; Jyqc2IH  
this.nSplitter = nSpiltter; #Z<a  
6KOlY>m]  
1"e)5xI  
} mI>,.&eo  
-P]sRl3O;  
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public String getSSiteURL() ^tCd L@$AS  
{ ]C:l,I  
return sSiteURL; <&:=z?30"  
} E_bO9nRHV  
Y
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public void setSSiteURL(String value) R?
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{ {4-[r#R<M  
sSiteURL = value; Yp:KI7  
} q.()z(M7  
v= N!SaK{  
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public String getSFilePath() QurW
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{ ZPD[5)~  
return sFilePath; Cj?L@%"  
} RJ$7XCY%`*  
NZ3/5%We/  
+r<0zh,n.  
public void setSFilePath(String value) [o<VVtB.Gk  
{ tyDM'|p  
sFilePath = value; 5T:i9h  
} I'@Ydt2  
Q(\4]i< S  
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public String getSFileName() k
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{ e~"f
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return sFileName; $]q8, N|1  
} Bk+{RN(w  
v%RP0%%{s  
A2nqf^b{#  
public void setSFileName(String value) is@b&V]  
{ M_%B|S {  
sFileName = value; l3IWoa&sh  
} >(snII  
bl'z<S, '  
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public int getNSplitter() YX_gb/A  
{ v$ub~Q6W  
return nSplitter; $/7pYl\n  
} m-jHze`D3  
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public void setNSplitter(int nCount) c-Pw]Ju  
{ +L5\;  
nSplitter = nCount; e0$=!QlPr  
} =dx1/4bZl|  
} !XzF67  
> z^#  
HdLH2+|P;D  
/* Ii:>xuF&  
**Utility.java {iq3|x2[:  
*/ -<_Ww\%8M  
package NetFox; {H{X[p8  
#-GJ&m8  
XduV+$03  
public class Utility { E(i[o?  
+z$pg  
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public Utility() W\L`5CW  
{ R9!Uo  
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} .%82P(  
Kn?lHH*w7  
//线程睡眠 e*.b3z  
public static void sleep(int nSecond) VnT>K9&3  
{ SnYLdwgl  
try{ H&yD*@  
Thread.sleep(nSecond); XB[<;*Iz  
} 0j_bh,zG#  
catch(Exception e) gp-T"l  
{ nIvJrAm4k  
e.printStackTrace (); Z'k|u4ZC  
} 9Mgq1Z  
} d|iy#hy"_  
Q*XE h  
//日志 q}FVzahv  
public static void log(String sMsg) aBzszp]l+  
{ @+WQ ^  
System.err.println(sMsg); C8L'si  
} +L=*:e\j  
y8\S}E0  
>~\89E02  
public static void log(int sMsg) MJ\eh>v&  
{ %riK+  
System.err.println(sMsg); k'PQ} ,Vb  
} d;+[i  
} Zx$ol;Yd  
W#Qmv^StZ  
_aPh(qprc  
/* ]0r|_)s  
**TestMethod.java 3or\:  
*/ #YSF&*  
package NetFox; &ciN@nJ|$z  
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8/"fWm
/  
public class TestMethod { q-Qxbg[>e  
Vj!
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wP/A^Rs  
public TestMethod() Eaqca{%/^  
{ ///xx/weblogic60b2_win.exe ?J,AB #+  
try{ j.:h5Y^N  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); x3zj?-  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); D\H/
  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ayBRWT0  
fileFetch.start(); AE@NOM7u  
} Urgtg37  
catch(Exception e){e.printStackTrace ();} TH&
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5#E |R  
} wJlX4cT4YV  
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m~'? /!!  
public static void main(String[] args) Yh)Isg|0>  
{ :L 3&FA  
new TestMethod(); sFDG)  
} W~Z<1[  
} a83g\c5   
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