http断点续传简单实现（java)

/* dJ9v/k_  
**SiteFileFetch.java Y-s6Z\  
*/ W9G1w
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package NetFox; E)iX`Xq|0{  
import java.io.*; xG1(vn83gq  
import java.net.*; ri1;i= W  
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public class SiteFileFetch extends Thread { KIGMWS^^  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 4J{W8jX  
long[] nStartPos; //开始位置 `uof\D<']  
long[] nEndPos; //结束位置 ^4~?]5Y\  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ]^0mh["  
long nFileLength; //文件长度 ANRZQpnXQ  
boolean bFirst = true; //是否第一次取文件 LL_@nvu}M  
boolean bStop = false; //停止标志 >H,5MM!  
File tmpFile; //文件下载的临时信息 HoO1_{q"  
DataOutputStream output; //输出到文件的输出流 }F';"ybrU)  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） emMk*l,  
public SiteFileFetch(SiteInfoBean bean) throws IOException lyzM?lK-  
{ .3CQFbHF  
siteInfoBean = bean; `$Y%c1;  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); <64#J9T^  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); _&RGhA  
if(tmpFile.exists ()) fP/;t61Z  
{ ;3\'}2^|l  
bFirst = false; 8xt8kf*k  
read_nPos(); 4jw q
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} _/NPXDL  
else c{3P|O&.  
{ U.Fs9F4M#  
nStartPos = new long[bean.getNSplitter()]; F*JbTEOn  
nEndPos = new long[bean.getNSplitter()]; jGUegeq  
} b=kY9!GN,v  
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} Dn48?A[v  
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public void run() #!C|~=  
{ o0_H(j?  
//获得文件长度 n(9$)B_y  
//分割文件 ~cf
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//实例FileSplitterFetch K?u:-
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//启动FileSplitterFetch线程 Ie}7#>S  
//等待子线程返回 sitgz)Ki^  
try{ rrSFmhQUk  
if(bFirst) ^[VEr"X  
{ t9r R>Y9  
nFileLength = getFileSize(); r2\}_pIj  
if(nFileLength == -1) Flaqgi/j  
{ \rY\wa  
System.err.println("File Length is not known!"); 2S//5@~_m  
} sWKv>bx  
else if(nFileLength == -2) kbSl.V%)  
{ n]8*yoge  
System.err.println("File is not access!");
{S`Rr/E|%  
} N}Or+:"O:q  
else NNBT.k3)  
{ nK`H;k  
for(int i=0;i<nStartPos.length;i++) U45-R-  
{ P! P` MX  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); DAy|'%rF1-  
} Y=@iD\u  
for(int i=0;i<nEndPos.length-1;i++) gZ us}U  
{ ir5e
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nEndPos = nStartPos[i+1]; ]/|D
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} b?/Su<q  
nEndPos[nEndPos.length-1] = nFileLength; \[ W`hhJ  
} 1 J[z ![Tf  
} @9lGU#  
~FVbL-2  
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//启动子线程 uT YG/O  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; A:\_ \B%<  
for(int i=0;i<nStartPos.length;i++) e 8^%}\F  
{ .*?)L3n+t  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ]dT]25V  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), (`<B#D;  
nStartPos,nEndPos,i); nv3TxG  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ?4t~z 1.f  
fileSplitterFetch.start(); MfraTUxIo/  
} 212 =+k  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), X7SSTcA  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 88}04  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 2
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nEndPos = " + nFileLength); mhF@S@  
// fileSplitterFetch[nPos.length-1].start(); _)~|Z~  
xR;z!Tg)  
)>]SJQ!k  
//等待子线程结束 @h5Q?I  
//int count = 0; +!t *LSF  
//是否结束while循环 a?)g>e HN  
boolean breakWhile = false; kdMB.~(K=  
{"0n^
!  
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while(!bStop) Is97>aid  
{ UJ`%uLR~  
write_nPos(); sA }X)aP  
Utility.sleep(500); Cyu
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breakWhile = true; G }M!  
\rCdsN2H  
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for(int i=0;i<nStartPos.length;i++) S;BMM8U  
{ p+2uK|T9  
if(!fileSplitterFetch.bDownOver) Y'y$k  
{ &#@"^(} 6  
breakWhile = false; ,88%eX|  
break; Pd(n|t3[8  
} YGi_7fTyc=  
} cSj(u%9}  
if(breakWhile) SNV;s,  
break; mN#&NA  
K4^B~0~  
?hW(5]p|  
//count++; lb]k"L%KU7  
//if(count>4) Lya?b  
// siteStop(); Kt_HJ!  
} [ <Q{  
V.[b${  
|h:3BV_  
System.err.println("文件下载结束！"); R xWD>:  
} }Ub "Vb  
catch(Exception e){e.printStackTrace ();} n4zns,:)/  
} os(}X(   
/`w'X/'VJ  
-Q!?=JNtQ  
//获得文件长度 ezd@>(hJ  
public long getFileSize() Kw>gg  
{ E}]SGU"  
int nFileLength = -1; _xdttO^N  
try{ ;~s@_}&  
URL url = new URL(siteInfoBean.getSSiteURL()); 73M;-qnU  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); EKT"pL-EY  
httpConnection.setRequestProperty("User-Agent","NetFox"); U9AtC.IG!  
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+Jc-9Ko\c;  
int responseCode=httpConnection.getResponseCode(); '`p0T%w  
if(responseCode>=400) vaZ?>94  
{ BimM)4g  
processErrorCode(responseCode); a[gN+DX%L  
return -2; //-2 represent access is error |nO}YU\E  
} Iq47^  
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String sHeader; 3lNw*M|")  
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for(int i=1;;i++) Xg97[I8/  
{ < YuI}d~'  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); \y/+H  
//Utility.log(in.readLine()); JDC,]  
sHeader=httpConnection.getHeaderFieldKey(i); 5TdI  
if(sHeader!=null) wT\dzp>/  
{ F^');8~L  
if(sHeader.equals("Content-Length")) @yjui  
{ ;Y16I#?;Kh  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); t,;b*ZR  
break; jdVdz,Y  
} j! cB  
} wmPpE_{  
else *-9b!>5eD  
break; n1c Q#u  
} M,UYDZ',  
} O4 Y;  
catch(IOException e){e.printStackTrace ();} Va'K~$d_  
catch(Exception e){e.printStackTrace ();} iAWoKW  
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Utility.log(nFileLength); <kor;exeJ  
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return nFileLength; >:P3j<xTv  
} RwwX;I"o%  
:Zd# }P  
^SRa!8z$W  
//保存下载信息（文件指针位置） 1vxh3KS.  
private void write_nPos() (.
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{
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try{ R:JS)>B  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ( ]o6Pi  
output.writeInt(nStartPos.length); iJE|u  
for(int i=0;i<nStartPos.length;i++) [G|2m_  
{ h Tn^:%(  
// output.writeLong(nPos); PZl(S}VY  
output.writeLong(fileSplitterFetch.nStartPos); =
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output.writeLong(fileSplitterFetch.nEndPos); u]cnbm  
} UoxF00H@!  
output.close(); s^{j  
} Jq`fD~
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catch(IOException e){e.printStackTrace ();} V1;Qt-i  
catch(Exception e){e.printStackTrace ();} ,K6]Q|U@r  
} {1YT a:evl  
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73(T+6`  
//读取保存的下载信息（文件指针位置） "$8<\k$LGT  
private void read_nPos() et]*5Y6  
{ bvR*
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try{ $Y0bjS2J  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); M+^K,  
int nCount = input.readInt(); #(*WxVE  
nStartPos = new long[nCount]; /ADxHw`k  
nEndPos = new long[nCount]; IJXH_H_%*  
for(int i=0;i<nStartPos.length;i++) LDvF)Eg  
{ =-pss 47  
nStartPos = input.readLong(); JnY3]  
nEndPos = input.readLong(); AQ 7e  
} ^! ZjK-$A<  
input.close(); cCV"(Oo[H|  
} {Q(6 .0R  
catch(IOException e){e.printStackTrace ();} P[nWmY  
catch(Exception e){e.printStackTrace ();} |2 wff?  
} xD?{Hw>QT#  
/9w}[y*E  
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private void processErrorCode(int nErrorCode) PewPl0  
{ X7c*T /  
System.err.println("Error Code : " + nErrorCode); Yhw* `"X  
} khv!\^&DD  
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}\DQxHG  
//停止文件下载 \ bT]?.si  
public void siteStop() n"K7@[d  
{ Z ''P5B;  
bStop = true; YJ16vb9  
for(int i=0;i<nStartPos.length;i++) 5!ReW39c;  
fileSplitterFetch.splitterStop(); /?XfVhA:A  
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4!}fC
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} >6DY3\  
} B?%D  
//负责部分文件的抓取 j'J*QK&Q  
**FileSplitterFetch.java \+AH>I;vO  
*/ VYAe!{[  
package NetFox; 4COf H7Al9  
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import java.io.*;  xBG1up<z  
import java.net.*; "\=_
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public class FileSplitterFetch extends Thread { gq@."wHU  
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String sURL; //File URL v/haUPWF\  
long nStartPos; //File Snippet Start Position XbOL/6V ^[  
long nEndPos; //File Snippet End Position BmJ?VJ}Y  
int nThreadID; //Thread's ID 5#F+-9r  
boolean bDownOver = false; //Downing is over j{
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boolean bStop = false; //Stop identical /(0d{  
FileAccessI fileAccessI = null; //File Access interface zXCIn  
PYf`a`dH  
:gVjBF2  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException "}EbA3  
{ O&s6blD11  
this.sURL = sURL; D_)vGvv3;.  
this.nStartPos = nStart; 3*TS 4xX  
this.nEndPos = nEnd; -&A[{m<,>  
nThreadID = id; ^>p [b  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 <XagkD  
} .2P?1H
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@6!JW(,]\  
public void run() >`uSNY"tO  
{ M Sj0D2H  
while(nStartPos < nEndPos && !bStop) !tdfTf$  
{ 1W g8jr's  
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try{ ;Z_C3/b  
URL url = new URL(sURL); ;^*!<F%t9R  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 9-^p23.@[j  
httpConnection.setRequestProperty("User-Agent","NetFox"); *La =7y:  
String sProperty = "bytes="+nStartPos+"-"; Q ?t  
httpConnection.setRequestProperty("RANGE",sProperty); `[&2K@u  
Utility.log(sProperty); /<$"c"UQ  
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InputStream input = httpConnection.getInputStream(); 5uer [1A  
//logResponseHead(httpConnection); }j1Zk4}[x  
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byte[] b = new byte[1024]; 0AKwZ' &H  
int nRead; *"\Q ~#W  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 9VE;I:NO3  
{ i)i)3K2  
nStartPos += fileAccessI.write(b,0,nRead); h.;CL#s  
//if(nThreadID == 1) ~,68S^nP)H  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Ne7{{1  
} EiN)TB^]  
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)  
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Utility.log("Thread " + nThreadID + " is over!"); }>~>5jc/Pg  
bDownOver = true; U]0)$OH5e  
//nPos = fileAccessI.write (b,0,nRead); \]A;EwC4C  
} _vV&4>  
catch(Exception e){e.printStackTrace ();} vqOLSE"t*O  
} tC:,!4 P$  
} TrU@mYnE  
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//打印回应的头信息 q{/Jw"e  
public void logResponseHead(HttpURLConnection con) l6c%_<P|  
{ uO(guA,C  
for(int i=1;;i++) \%Rta$O?S  
{ F^t?*   
String header=con.getHeaderFieldKey(i); ,l .U^d6>  
if(header!=null) N%A`rY}u  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); y!N)@y4  
Utility.log(header+" : "+con.getHeaderField(header)); `L#?eQ{  
else 2^#UO=ct  
break; ;sR6dT)  
} ?_>^<1I1  
} .00=U;H%`  
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public void splitterStop() 1bZiPG{  
{ |cGeL[  
bStop = true; #S%Y;ilq  
} ^;$a_$|  
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} !u{"] T:  
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/* Z3So|M{v  
**FileAccess.java
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*//文件访问(定位，写) - (_e=3$  
package NetFox; +^DRto=  
import java.io.*; +1Rrkok  
eSX[J6  
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public class FileAccessI implements Serializable{ cYM~IA  
U+PCvl=x  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Cz@FZb8  
RandomAccessFile oSavedFile; TDFO9%2c  
long nPos; ^b!7R <>~  
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public FileAccessI() throws IOException `X<`j6zaG  
{ [s{r$!Gl  
this("",0); 4:Xj-l^D  
} "Z2Tc)  
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public FileAccessI(String sName,long nPos) throws IOException *e3L4 7"G  
{ |\%F(d330  
oSavedFile = new RandomAccessFile(sName,"rw"); 3> \fP#oQ  
this.nPos = nPos; C8qTz".5$  
oSavedFile.seek(nPos); 0L0Jc,(F+  
} 3Wb2p'V7$?  
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public synchronized int write(byte[] b,int nStart,int nLen) r=DHt&x=  
{ PM-PP8h  
int n = -1; Q6.*"`  
try{ qTTn51  
oSavedFile.write(b,nStart,nLen); ";_K x={  
n = nLen; PG6L]o^  
} 7mn,{2  
catch(IOException e) #5-A&  
{ Xvu)  
e.printStackTrace (); P 0Efh?oZ  
} Y$x"4=~  
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return n; G&@-R{i  
} I[=Wmxa?r  
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} 0Q$~
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/* B9LSxB  
**SiteInfoBean.java R2N^'  
*/
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package NetFox; jy!f{dsC  
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public class SiteInfoBean { 3q#"i&  
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private String sSiteURL; //Site's URL "J P{Q  
private String sFilePath; //Saved File's Path T/wM(pr'   
private String sFileName; //Saved File's Name Mu'^OX82  
private int nSplitter; //Count of Splited Downloading File +MNSZLP]  
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public SiteInfoBean() JlC<MQ?  
{//nSplitter的缺省值为5 J[}gku?C;  
//default value of nSplitter is 5 8Wdkztp/S  
this("","","",5); Ii~; d3.  
} 0{0;1.ZP  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) h4XcKv+  
{ WYwzo V-  
sSiteURL= sURL; _x\-!&[p  
sFilePath = sPath; +R "AA_A?  
sFileName = sName; S)"##-~`T  
this.nSplitter = nSpiltter; YKP=0 j3,  
|?x^8e<*  
7$+P|U
 
} >oft :7p  
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public String getSSiteURL() /rIm7FW)  
{ yy1>r }L  
return sSiteURL; <G\ <QV8W  
} 6sYV7w,'@  
7o;x
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>"cr-LB  
public void setSSiteURL(String value) s.^c..e75C  
{ Z$!C=  
sSiteURL = value; OM20-KDc5  
} :v#k&Uh3y  
W *YW6  
j6n2dMRvSE  
public String getSFilePath() #"Fg%36Zd  
{ '1CD- Bu  
return sFilePath; L"[IOV9S  
} oy2(Ag\  
T(Y}V[0+  
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public void setSFilePath(String value) iY0,WT}&n  
{ 13ipaz  
sFilePath = value; 4dW3'"R"L  
} yDd=& T   
4JGE2ArR  
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public String getSFileName() u=vh Z%A]  
{ /GsSrP_?]  
return sFileName; o*%3[HmV  
} *Jb_=
j*)  
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public void setSFileName(String value) j
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{ &nQRa?3,   
sFileName = value; mYjf5  
} 5\VxXiy0  
%z1{Kus  
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public int getNSplitter() S&n[4*  
{ q z=yMIy=  
return nSplitter; b![t6-f^z  
} U8YO0}_z  
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public void setNSplitter(int nCount) 0;vtdM[_  
{ PT mf  
nSplitter = nCount; >P(eW7RL  
} :OHSxb>[  
}  q4_**  
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/* F b1EMVu  
**Utility.java `Gf{z%/  
*/ 9^oo-,Su_  
package NetFox; y0;,dv]  

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(%i!%{!]  
public class Utility { O-Dc[t%  
gyC^K3}  
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public Utility() -eUV`&[4  
{ NzAQ@E2d:  
9KXym
}  
QS\Uq(Ja\  
}
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SAP;9*f1\  
//线程睡眠 8AryIgy>@  
public static void sleep(int nSecond) D^nxtuT*  
{ >Z}@7$(7!~  
try{ B-$+UE>%  
Thread.sleep(nSecond); XHy?  
} Y7-*2"!  
catch(Exception e) 4*iHw+%mq  
{ 9-b 8`|s  
e.printStackTrace (); R^w}o,/  
} M]1;  
} GN0duV  
N.jA 8X  
//日志 Hv3W{
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public static void log(String sMsg) (e(Rr4  
{ )R~a;?T_c0  
System.err.println(sMsg); 2@fa rx:  
} +1x)z~q=  
zFOL(s.h|0  
!Pw$48cg  
public static void log(int sMsg) 1ADv?+j)A/  
{ ^L ]B5,}-  
System.err.println(sMsg); N^lAG"Jao[  
} wajZqC2yg  
} 4x(F&0  
bhn5Lz$z  
ZlrhC= 0  
/* s*f1x N<  
**TestMethod.java qT$)Rb&  
*/ <iRWd  
package NetFox; X3AwM%,!  
zLL)VFCJW  
b) Ux3PB  
public class TestMethod { of=ql  
I :@|^PYw  
`&H04x"Y$>  
public TestMethod() Y_+ SA|s  
{ ///xx/weblogic60b2_win.exe hl**zF  
try{ 5\&]J7(  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Uh}+"h5  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ]'tJ S
]  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 4b=
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fileFetch.start(); \KCWYi]  
} i$["aP~G  
catch(Exception e){e.printStackTrace ();} D!S8oKW  
^@K WYAAW5  
8]HY. $E  
} %{U"EZ]D!  
5*Btb#:  
;7L;  
public static void main(String[] args) 3 &Sp@,  
{ k1RV'  
new TestMethod(); /eb-'m  
} !O8.#+  
} ^iuo^
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