http断点续传简单实现（java)

/* tkm@&e=e%  
**SiteFileFetch.java 4/{pz$  
*/ OH`zeI,[*  
package NetFox; {~]5QKg.  
import java.io.*; l#C<bDw  
import java.net.*; 1F>8#+B/W  
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public class SiteFileFetch extends Thread { n&&C(#mBC  
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SiteInfoBean siteInfoBean = null; //文件信息Bean vK/`or3U  
long[] nStartPos; //开始位置 5h Sd,#:  
long[] nEndPos; //结束位置 #s(ob `0|  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 bZUw^{~)D  
long nFileLength; //文件长度 OR+_s @Yg  
boolean bFirst = true; //是否第一次取文件 &b,A-1`w_  
boolean bStop = false; //停止标志 QsPg4y3?D  
File tmpFile; //文件下载的临时信息 \s)$
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DataOutputStream output; //输出到文件的输出流 X!6dg.n5  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 8[,R4@  
public SiteFileFetch(SiteInfoBean bean) throws IOException vv)O+xt  
{ }vx 46  
siteInfoBean = bean; q;QasAQS`p  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); #F3'<(j  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); <i]-.>&J  
if(tmpFile.exists ()) s^6,"C  
{ 2N |iOog  
bFirst = false; ,>qtnwvlHP  
read_nPos(); +8"8s  
} tUJe-3,  
else e]>=;Zn  
{ Ui"$A/  
nStartPos = new long[bean.getNSplitter()]; .PT7  
nEndPos = new long[bean.getNSplitter()]; F@ |(  
} @6|0H`kv  
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} +>eX1WoTy  
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public void run() b^<7a&  
{ r91i :  
//获得文件长度 sqF.,A,  
//分割文件 CD#U`jf  
//实例FileSplitterFetch /W f.Gt9[  
//启动FileSplitterFetch线程 #D(=[F  
//等待子线程返回 |;aZi?Ek[  
try{ "ivVIq2  
if(bFirst) t:oq'
t  
{ BINHCZ  
nFileLength = getFileSize(); =^
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if(nFileLength == -1) #~m^RoE  
{ wNl6a9#  
System.err.println("File Length is not known!"); AK'3N1l`  
} !.iFU+?V  
else if(nFileLength == -2) #68$'Rl"o1  
{ bM_fuy55Op  
System.err.println("File is not access!"); @@R&OR  
} l| \ -d  
else ettBque  
{ vd^Z^cpip  
for(int i=0;i<nStartPos.length;i++) Xg
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{ {Z
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); 1)~9Eku6K  
} n/BoK6g  
for(int i=0;i<nEndPos.length-1;i++) .MDSP/s  
{ ['>r tV  
nEndPos = nStartPos[i+1]; Zs0;92WL  
} pwSkwJ]  
nEndPos[nEndPos.length-1] = nFileLength; {#@[ttw$U  
} ~z41$~/  
} 1S+T:n  
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//启动子线程 zcOm"-E-  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ^I6Vz?0Jl  
for(int i=0;i<nStartPos.length;i++) c9nv=?/}f  
{ )FA:
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fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 9P#kV@%(0c  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), m4~~q[t  
nStartPos,nEndPos,i); R;U4a2~  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 2Z"\%ZD  
fileSplitterFetch.start(); F
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} N48X[Q*  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ox.kL  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); MR@Qn[RdM  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 0[uOKFgE  
nEndPos = " + nFileLength); 9&kPcFX B  
// fileSplitterFetch[nPos.length-1].start(); ^*y1Fn0  
48;b  
c\szy&W  
//等待子线程结束 RMs8aZCa  
//int count = 0; KdTWi;mV2-  
//是否结束while循环 4}0YLwgJ  
boolean breakWhile = false; ]H`pM9rC  
w!d(NA<|0]  
!w!k0z]  
while(!bStop) %bdBg  
{ _D+J3d(Pjk  
write_nPos(); DV({! [EP  
Utility.sleep(500); `4Z:qh+fJ  
breakWhile = true; NVom6K  
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for(int i=0;i<nStartPos.length;i++) Lcy6G%A  
{ AEFd,;GF  
if(!fileSplitterFetch.bDownOver) eAQ-r\h'2  
{ Z)3oiLmD  
breakWhile = false; |hDN$By  
break; 0x&L'&SpN  
} x>4p6H{]0'  
} 3RlNEc%)  
if(breakWhile) lF7".  
break; NUh%\{  
NP!LBB)=Y  
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//count++; Az?^4 1r8  
//if(count>4) VS~+W
=5}  
// siteStop(); ~
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} 66MUrNW  
PCH$)F4^  
 Cz&t*i/  
System.err.println("文件下载结束！"); ]R09-s 0$7  
} 3:OqD~,zy  
catch(Exception e){e.printStackTrace ();} ka`}lR  
} p~(STHDe#  
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//获得文件长度 N /;Vg^Wx  
public long getFileSize() ~xJr|_,gp  
{ c|iTRco  
int nFileLength = -1; 11A$#\,  
try{ 5@W63!N  
URL url = new URL(siteInfoBean.getSSiteURL()); @6;ZP1  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 0uGTc[^^M  
httpConnection.setRequestProperty("User-Agent","NetFox"); cp`ZeLz2^  
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int responseCode=httpConnection.getResponseCode(); Xoq
-  
if(responseCode>=400) Smh=Q4,W  
{ $p}q,f.  
processErrorCode(responseCode); T$DFTr\\  
return -2; //-2 represent access is error G8Ow;:Ro  
} ':=20V  
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String sHeader; ).tTDZ   
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for(int i=1;;i++) )2jH&}K  
{  z'5  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ?cK67|%W  
//Utility.log(in.readLine()); x.I?)x!C'  
sHeader=httpConnection.getHeaderFieldKey(i); @Rd
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if(sHeader!=null) DoN]v  
{ #,
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if(sHeader.equals("Content-Length")) u0ZMrIJ  
{ U4iVI#f  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); je%y9*V  
break; ?|Wxqo  
} 95/;II  
} A=D G+z''  
else SK@lr  
break; }n,LvA@[0  
} 1:{+{Yl7  
} =[TXH^.0  
catch(IOException e){e.printStackTrace ();} + =U9<8  
catch(Exception e){e.printStackTrace ();} ,o3`O|PiK  
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Utility.log(nFileLength); ?'t
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return nFileLength; F*4G@)  
} zRR^v&.9K  
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//保存下载信息（文件指针位置） J!QIMA4{  
private void write_nPos() -(#`JT8  
{ btDTC
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try{ Izfq`zS+\s  
output = new DataOutputStream(new FileOutputStream(tmpFile)); O? 7hT!{  
output.writeInt(nStartPos.length); _~y-?(46K  
for(int i=0;i<nStartPos.length;i++) mF
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{ |uJjO>8]|  
// output.writeLong(nPos); nbDjoZZ4  
output.writeLong(fileSplitterFetch.nStartPos); IY@N  
output.writeLong(fileSplitterFetch.nEndPos); OskQ[ e0  
} H<*n5r(c  
output.close(); 5VGZ5,+<<  
} 7e)j|a-!<  
catch(IOException e){e.printStackTrace ();} EgOiJH  
catch(Exception e){e.printStackTrace ();} ~UwqQD1p
 
} \`*]}48Z  
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//读取保存的下载信息（文件指针位置） y XCZs  
private void read_nPos() L*{E-m/  
{ Yg;7TKy  
try{ ;
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DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); LS<*5HWX  
int nCount = input.readInt(); ,jy9\n*<t9  
nStartPos = new long[nCount]; Q_k'7Z\g$  
nEndPos = new long[nCount]; Z v 7}C  
for(int i=0;i<nStartPos.length;i++) ]-OF3+l4  
{ zpcO7AY~  
nStartPos = input.readLong(); @|d`n\%x  
nEndPos = input.readLong(); IL%P\Zs  
} 7v`~;}5  
input.close();
d @b ]/  
} e,*@+E\4  
catch(IOException e){e.printStackTrace ();} aL8Z|*  
catch(Exception e){e.printStackTrace ();} K[q-[q#yc  
} PD^Cj?wm  
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private void processErrorCode(int nErrorCode) 8`|Z9umW*  
{ /!hxW}>^  
System.err.println("Error Code : " + nErrorCode); gjB(Pwx  
} @M(+YCi:e@  
~yY5pnJ  
{w v{"*Q9Q  
//停止文件下载 UrdSo"%  
public void siteStop() ERfSJ  
{ -Y>QKS  
bStop = true; 'lgS;ItpKu  
for(int i=0;i<nStartPos.length;i++) VH~ZDZ1P  
fileSplitterFetch.splitterStop(); `I(5Aj"  
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} A-u}&}l<  
} yk2XfY  
//负责部分文件的抓取 fTi5Ej*/?)  
**FileSplitterFetch.java X$SXDb~G  
*/ sGGi7%  
package NetFox; CmtDfE  
58PL@H~@0  
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import java.io.*; r<$"T  
import java.net.*; T?{F7  
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public class FileSplitterFetch extends Thread { J+qcA}  
v2vtkYQN  
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String sURL; //File URL *>jJ<8!  
long nStartPos; //File Snippet Start Position Z07SK 'U  
long nEndPos; //File Snippet End Position |bk$VT4\  
int nThreadID; //Thread's ID =qww|B92  
boolean bDownOver = false; //Downing is over 9y;zk$O8  
boolean bStop = false; //Stop identical jjg[v""3|  
FileAccessI fileAccessI = null; //File Access interface W'5c%SI  
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:?\Je+iA  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException a=*JyZ.2  
{ KtaoU2s  
this.sURL = sURL; F7`[r9 $  
this.nStartPos = nStart; T{*!.+E  
this.nEndPos = nEnd; W"5VqN6v  
nThreadID = id; S8;5|ya  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 s 5F?m  
} ^7Z.~A y  
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public void run() >2#F5c67  
{ v<gve<]  
while(nStartPos < nEndPos && !bStop) BBj>ML\X  
{ 3Sn# M{wH  
Q'Y7PG9m~  
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try{  9-Xr  
URL url = new URL(sURL); (6i.>%|_  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); =la~D]T*g  
httpConnection.setRequestProperty("User-Agent","NetFox"); ;2547b[]  
String sProperty = "bytes="+nStartPos+"-"; @E?o~jO(e  
httpConnection.setRequestProperty("RANGE",sProperty); &xS] ;Fr  
Utility.log(sProperty); mz3Dt>  
;<BMgO}N  
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InputStream input = httpConnection.getInputStream(); o AM)<#U>  
//logResponseHead(httpConnection); P"Y7N?\](  
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byte[] b = new byte[1024];  $kY ]HI  
int nRead; \C"hL(4-  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) {0\9HI@  
{ jR^_1bu  
nStartPos += fileAccessI.write(b,0,nRead); 1-8G2e  
//if(nThreadID == 1) *NoixV1>  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); w*gG1BV  
} XK/bE35%^!  
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Utility.log("Thread " + nThreadID + " is over!"); lT;uL~j  
bDownOver = true; Di&XDW/  
//nPos = fileAccessI.write (b,0,nRead); j2=|,AmC  
} n?8xRaEf  
catch(Exception e){e.printStackTrace ();} 1oL3y;>iL  
} h&:XO9dY  
} ?GeMD /]  
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hfRxZ>O2  
//打印回应的头信息 0!q@b  
public void logResponseHead(HttpURLConnection con) yjIA`5^  
{ kB_T9$0e#  
for(int i=1;;i++) =$\9t$A  
{ SF[}suL  
String header=con.getHeaderFieldKey(i); :[ll$5E.  
if(header!=null) J{PNB{v  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); .c\iKc#  
Utility.log(header+" : "+con.getHeaderField(header)); *Jg&:(#}<J  
else (vwKC D&  
break; nYy+5u]FG  
} 8l >Xbz  
} |L(h+/>aWX  
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*JiI>[  
public void splitterStop() qR9!DQc'  
{ uevhW  
bStop = true; !
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} #?7g_  
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} af}JS2=$  
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/* REJHh\:.77  
**FileAccess.java #bGYd}BfD  
*//文件访问(定位，写) WUGFo$xA  
package NetFox; 8_T9[]7V8  
import java.io.*; \n^;r|J7k  
mQ^SpK #  
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public class FileAccessI implements Serializable{ & DhdB0Hjf  
{ukQBu#}<  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 'm.+S8  
RandomAccessFile oSavedFile; |P7FP
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long nPos; t
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'j\mz5#s  
public FileAccessI() throws IOException v>0} v)<v  
{ b8|<O:]Hp  
this("",0); YhL^kM@c  
} q5\iQ2f{WV  
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| &/_{T  
public FileAccessI(String sName,long nPos) throws IOException 05o<fa2HE  
{ W;|%)D)y
 
oSavedFile = new RandomAccessFile(sName,"rw"); 'q1cc5(ueV  
this.nPos = nPos; +nL#c{  
oSavedFile.seek(nPos); j5rMY=|F  
} DY1"t7 9E  
Hh* KcIRX  
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public synchronized int write(byte[] b,int nStart,int nLen) #q6#nfi"  
{ >O~   
int n = -1; lg*?w/JX+  
try{ Hd_,`W@
 
oSavedFile.write(b,nStart,nLen); 0e(4+:0  
n = nLen; +6:jm54  
} i'[! 'HY  
catch(IOException e) :jFZz%   
{ $0Un'"`S  
e.printStackTrace (); {TaYkuWS  
} F[>Y8e<[  
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return n; eQ<Vky^SJ  
} %<<JWoB  
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} .pIO<ZAFT  
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+NVXFjPC  
/* Cm9#FA  
**SiteInfoBean.java 2IXtIE  
*/ 5RyxVC0<  
package NetFox;  vPAL,  
h
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5 hW#BB  
public class SiteInfoBean { Ugme>60`'k  
&FWz7O>1  
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private String sSiteURL; //Site's URL WG +]  
private String sFilePath; //Saved File's Path ~bz$]o-<  
private String sFileName; //Saved File's Name 9K-,#a  
private int nSplitter; //Count of Splited Downloading File uobQS!  
vb3hDy  
8WC_CAP  
public SiteInfoBean() 0bteI*L  
{//nSplitter的缺省值为5 ZtY?X- 4_  
//default value of nSplitter is 5 ~Gl5O`w(  
this("","","",5);
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} :"cKxd  
8y;gs1d;A  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) mSGpxZ,IE  
{ *0'< DnGW  
sSiteURL= sURL; GU]kgwSfi  
sFilePath = sPath; I8k+Rk*  
sFileName = sName; ~cV";cD5  
this.nSplitter = nSpiltter; X6xs@tgQ  
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Y++n0sK5<  
} ll*Ez"  
}:(;mW8 D  
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public String getSSiteURL() `nY.&YT  
{ >X*Y jv:r  
return sSiteURL; \{v-Xe&d^  
} lv+: `  
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public void setSSiteURL(String value) Y7;=\/SV  
{ tl`x/  
sSiteURL = value; zR)/h   
} O^@F?CG :1  
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public String getSFilePath() Y(gai?  
{ |XV`A)=f  
return sFilePath; N?O^
"  
} stiYC#bI:  
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public void setSFilePath(String value) p3e=~{v*  
{ ^tIYr<I  
sFilePath = value; 4/OmgBo'  
} tlB-s;  
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a  
public String getSFileName() $F NH:r<  
{ N%%trlDXD  
return sFileName; Lcf?VV}  
} U2CC#,b!(  
8fktk?|  
q/ (h{cq  
public void setSFileName(String value) Y*IKPnPot2  
{ ,aIkiT  
sFileName = value; `G%h=rr^c  
} 1DGl[k/zv  
Z[>fFg~N4  
8U}+9  
public int getNSplitter() I'[;E.KU  
{ Rtlc&Q.b  
return nSplitter; VP<LY/'f  
} QL*RzFAD3  
(G(M"S SC  
>XX93  
public void setNSplitter(int nCount) `I(ap{  
{ |;&I$'i  
nSplitter = nCount; r! [Qpb-:  
} xzOn[.Fi  
} :#cJZ\YH  
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+ R~!G  
/* y=Z[_L!xr  
**Utility.java &WOm[]Q4  
*/ +\?+
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package NetFox; /U-+ClZi@  
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public class Utility { o-JB,^TE  
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_>;{+XRX[  
public Utility() XVb9)a  
{ L-9;"]d~|  
+ej5C:El_}  
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} ?@kz`BY  
I!SIy&=W  
//线程睡眠 xM@s`s|n  
public static void sleep(int nSecond) ]9c{qm}y  
{ Mpco8b-b  
try{ G~ LQM  
Thread.sleep(nSecond); l/"!}wF  
} &N]e pV>  
catch(Exception e) %~k
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{ YY
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e.printStackTrace (); 9c[b
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} 53d`+an2  
} Cl3L)  
Br.UN~q  
//日志 V<?0(esgR  
public static void log(String sMsg) |WSpWsr,  
{ RC
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System.err.println(sMsg); At !:d3  
} *'tGi_2?(  
/I{K_G@  
f2&6NC;  
public static void log(int sMsg) 5.DmMG[T^=  
{ GG-b)64h`  
System.err.println(sMsg); [:qJ1^UU  
} f6nuh&!-  
} UZmo?&y  
d|)ARRW  
#p]V?  
/* uy~$ :0o  
**TestMethod.java IKaW],sr#  
*/ =e0MEV#s.  
package NetFox; C'{B  
-$Kc"rX  
g9NE>n(3  
public class TestMethod { s@GE(Pu7  
1ox#hQBoS  
XsDZ<j%x89  
public TestMethod() >< P<k&  
{ ///xx/weblogic60b2_win.exe 7=Pj}x)  
try{ j>l  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); hJ8%r_  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); vK+!m~kDu  
SiteFileFetch fileFetch = new SiteFileFetch(bean); .o,-a>jL  
fileFetch.start(); 2v;&`04V<  
} Bj9FSKiH  
catch(Exception e){e.printStackTrace ();} _HjB'XNr(  
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33wVP}e5  
} MPn/"Fij$  

+$xw0)|  
7i'clB9!  
public static void main(String[] args) cfRUVe  
{ ^:mKTiA-  
new TestMethod(); ~4Mz:h^  
} g0;
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} ld):Am}/o  
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