http断点续传简单实现（java)

/* vtRz;~,Z  
**SiteFileFetch.java it->)?"(6  
*/ m" ]VQnQ  
package NetFox; zRB LkrC  
import java.io.*; {&nDm$KTD  
import java.net.*; QM{B(zH  
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public class SiteFileFetch extends Thread { H:mcex  
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SiteInfoBean siteInfoBean = null; //文件信息Bean B
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long[] nStartPos; //开始位置 2>m"CG  
long[] nEndPos; //结束位置 G~/*!?&z  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 1{G@'#(  
long nFileLength; //文件长度  k.\4<}  
boolean bFirst = true; //是否第一次取文件 4Td)1~zc3  
boolean bStop = false; //停止标志 !)(To  
File tmpFile; //文件下载的临时信息 ,t39~w  
DataOutputStream output; //输出到文件的输出流 /`7G7pQ+  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） [o.#$(   
public SiteFileFetch(SiteInfoBean bean) throws IOException 8]WcW/1r !  
{ s 4n<k]d  
siteInfoBean = bean; i1!Y{  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 6df`]sc  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); o}yA{<"  
if(tmpFile.exists ()) |oR#j `  
{ n`p/;D=?  
bFirst = false; m[Qr>="  
read_nPos(); ix 5\Y  
} [!4V_yOb  
else 1czU$!MV  
{ sAjN<P  
nStartPos = new long[bean.getNSplitter()]; a
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nEndPos = new long[bean.getNSplitter()]; *]ME]2qP  
} 8x9;3{R  
9 $zx<O  
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} `8;\}6:"1  
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public void run() u89Q2\z~"M  
{
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//获得文件长度 ~jJe|zg>  
//分割文件 t!0 IQ9\[*  
//实例FileSplitterFetch /L` +  
//启动FileSplitterFetch线程 )~#3A@  
//等待子线程返回
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try{ DK#Tr: 7  
if(bFirst) QV _aM2  
{ cgR8+o  
nFileLength = getFileSize(); t]xR`Rr;X  
if(nFileLength == -1) UhSaqq  
{ }L>0}H  
System.err.println("File Length is not known!"); Q1x=@lXR  
} wLo<gA6;  
else if(nFileLength == -2)
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{ cq8JpSB(  
System.err.println("File is not access!"); kM3#[#6$!  
} _"82W^Wi  
else Nk?/vMaw  
{ ]F"@+_E  
for(int i=0;i<nStartPos.length;i++) v5*JBW+c*  
{ 2D"aAI<P  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 3GXmyo:o$  
} aF.fd2k  
for(int i=0;i<nEndPos.length-1;i++) }q:4Zh'l!  
{ (1%A@4  
nEndPos = nStartPos[i+1]; c`7dNx  
} PsN_c[+  
nEndPos[nEndPos.length-1] = nFileLength; nsu RG  
} 3u9}z+q  
} y.::d9v  
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_:!7M^IU  
//启动子线程 ;;Jx1Q  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Pe`jNiI  
for(int i=0;i<nStartPos.length;i++) `Yyi;!+0  
{ |zOwC9-6  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), aX.//T:':?  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), tQ`|MO&o  
nStartPos,nEndPos,i); H1$n6J  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); l<yYfGO  
fileSplitterFetch.start(); &cy<"y  
} Gl9,!"A  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), eU\_m5xl"  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); &PFK0tY  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", _[N*k"  
nEndPos = " + nFileLength); fj[Kbo 7!h  
// fileSplitterFetch[nPos.length-1].start(); M} Mgz  
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{
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//等待子线程结束 S4 s#EDs  
//int count = 0; </_.+c [  
//是否结束while循环 |q Pu*vR  
boolean breakWhile = false; 2 e&M/{  
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while(!bStop) p+${_w>pl{  
{ '>t'U?7w<  
write_nPos(); 5`q#~fJ2  
Utility.sleep(500); 9yj'->dL  
breakWhile = true; XjTu`?Na;  
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for(int i=0;i<nStartPos.length;i++) )oZ2,]us!  
{ iK8jX?  
if(!fileSplitterFetch.bDownOver) Myh?=:1~(c  
{ f\H1$q\p\  
breakWhile = false; -f"{%<Q  
break; /?*ut
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} ix
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} Twk<<  
if(breakWhile) Ka$lNL3<j  
break; s$ ?;C  
40 zO4  
mcxD#+H 3  
//count++; xggF:El3{  
//if(count>4) \9]-(j6[H  
// siteStop(); n'!x"O7  
}  Au*1-  
xxOhGA)  
593!;2/@  
System.err.println("文件下载结束！"); ,Uy;jk  
} Ei89Ngp\}  
catch(Exception e){e.printStackTrace ();} 3Qu-X\  
} D0h6j0r5  
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//获得文件长度 `)TgGny01  
public long getFileSize() P[jh^!<j  
{ IaO*{1re  
int nFileLength = -1; q&^H" fF  
try{ 6I
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URL url = new URL(siteInfoBean.getSSiteURL()); kR{$&cE^  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); CW+gZ!  
httpConnection.setRequestProperty("User-Agent","NetFox"); uFFC.w  
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chM-YuN|  
int responseCode=httpConnection.getResponseCode(); {d> 6*b  
if(responseCode>=400) cvYKZB  
{ :c(#03w*C  
processErrorCode(responseCode); l0tFj>q"  
return -2; //-2 represent access is error l)V646-O,~  
} (*\y  
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String sHeader; TW=N+ye^1(  
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for(int i=1;;i++) ypx`!2Q$  
{ A>\3FeU>UC  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); >S%}HSPKq  
//Utility.log(in.readLine()); NWj4U3x  
sHeader=httpConnection.getHeaderFieldKey(i); !
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if(sHeader!=null) }sp?@C,Z  
{ AnpO?+\HF  
if(sHeader.equals("Content-Length")) ;Hb"SB  
{ =>7czw:S1  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); /Z]hX*QR  
break; 4G RHvA.  
} /bmkt@$-0  
} xM/WS':V  
else P1<McQ  
break; c)c_Qv  
} z2q!_ ~  
} U@:l~xJ  
catch(IOException e){e.printStackTrace ();} <"av 
/`;  
catch(Exception e){e.printStackTrace ();} @.pr}S/  
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Utility.log(nFileLength); R S] N%`]  
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return nFileLength; qJw\<7m  
} 2FGCf} ,  
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2~hQ   
//保存下载信息（文件指针位置） s:I 8~Cc  
private void write_nPos() JC}T*h>Ee  
{ y8]vl;88yY  
try{ CS0q#?  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 5'_:>0}  
output.writeInt(nStartPos.length); kqGydGh*"  
for(int i=0;i<nStartPos.length;i++) 0UQ DB5u  
{ m`jGBSlw_  
// output.writeLong(nPos); l I2UpfkBP  
output.writeLong(fileSplitterFetch.nStartPos); l>)+HoD  
output.writeLong(fileSplitterFetch.nEndPos); %m$t'?  
} 2 S2;LB  
output.close(); ,/[1hhP@  
} Ld=6'C8ud  
catch(IOException e){e.printStackTrace ();} Vc+~yh.)  
catch(Exception e){e.printStackTrace ();} ;}k_  
} T;i+az{N:V  
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//读取保存的下载信息（文件指针位置） =UxKa`  
private void read_nPos() },#AlShZu  
{ ZT+{8,  
try{ 8an_s%,AW  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); DXK\3vf Ot  
int nCount = input.readInt(); \p)eY#A  
nStartPos = new long[nCount]; h{ eQ\iI  
nEndPos = new long[nCount]; 8'u,}b)  
for(int i=0;i<nStartPos.length;i++) w7~&Xxa/  
{ _HkQv6fXpE  
nStartPos = input.readLong(); F0'8n6zj  
nEndPos = input.readLong(); lT'V=,Y t  
} f1U:_V^d  
input.close(); =-G4BQ  
} Sf t,$  
catch(IOException e){e.printStackTrace ();} ")w~pZE&+  
catch(Exception e){e.printStackTrace ();} w# ;t$qz}  
} Vb?_RE_H  
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private void processErrorCode(int nErrorCode) d/E0opv  
{ +@<@x4yt  
System.err.println("Error Code : " + nErrorCode); axv-UdE;  
} F^Mt}`O  
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8vUq8[[  
//停止文件下载 DhG{hQ[[  
public void siteStop() DMT2~mh  
{ z{qn|#}  
bStop = true; h5[.G!  
for(int i=0;i<nStartPos.length;i++) :Y)G-:S+  
fileSplitterFetch.splitterStop(); :kucDQE({?  
mm N$\2  
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} 5%"0  
} Vje LPbk)  
//负责部分文件的抓取 d^`n/"Ice  
**FileSplitterFetch.java /-g%IeF  
*/ #}8gHI-9%  
package NetFox; NaeG)u#+  
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import java.io.*; Y+3r{OI  
import java.net.*; 
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public class FileSplitterFetch extends Thread { ] -G~  
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String sURL; //File URL , ins/-3  
long nStartPos; //File Snippet Start Position h8HA^><Xr  
long nEndPos; //File Snippet End Position z4(Q.0x7  
int nThreadID; //Thread's ID Xyw;Nh!!d  
boolean bDownOver = false; //Downing is over )(`,!s,8)  
boolean bStop = false; //Stop identical #:nds,  
FileAccessI fileAccessI = null; //File Access interface !^w}Sp  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException wdEQB-d
A  
{ /^Zgv-n  
this.sURL = sURL; 0+_:^z  
this.nStartPos = nStart; q7zHT=@$  
this.nEndPos = nEnd; PL*kjrLu7  
nThreadID = id; vrXNa8,L  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ffh3okyW0  
} 2tdr1+U?g  
;5=5HYx%  
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public void run() [1.>9ngj  
{ ](^BQc  
while(nStartPos < nEndPos && !bStop) 50`<[w<J q  
{ vv`,H~M6  
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try{ W sDFui  
URL url = new URL(sURL); YXTd^M~@D  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); [f-<M@id/  
httpConnection.setRequestProperty("User-Agent","NetFox"); >^d+;~Q;  
String sProperty = "bytes="+nStartPos+"-"; fvw&y+|y!  
httpConnection.setRequestProperty("RANGE",sProperty); :JG2xtn  
Utility.log(sProperty); YDiru  
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InputStream input = httpConnection.getInputStream(); qISzn04  
//logResponseHead(httpConnection); ?r(Bu  
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byte[] b = new byte[1024]; N`!=z++G  
int nRead; 98t|G5  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) "\x\P)j0>  
{ 2]-xmS>|b  
nStartPos += fileAccessI.write(b,0,nRead); `Z~\&r=  
//if(nThreadID == 1) JJE0q5[  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); REKv&^FLN  
} ;NrU|g/ksX  
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Utility.log("Thread " + nThreadID + " is over!"); T\$r|  
bDownOver = true; oA
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//nPos = fileAccessI.write (b,0,nRead); H%`|yUE(  
} /mFa*~dj2  
catch(Exception e){e.printStackTrace ();}
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} mi$*,fz  
} ~JxAo\2i  
#kL4Rm;  
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//打印回应的头信息 .g95E<bd  
public void logResponseHead(HttpURLConnection con)  FR1se  
{ `1)n2<B  
for(int i=1;;i++) 7%Ii:5Bp  
{ (%f2ZNen  
String header=con.getHeaderFieldKey(i); (= ,w$  
if(header!=null) rQD7ZN_ R  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ,#QLc  
Utility.log(header+" : "+con.getHeaderField(header)); gIaPS0Q
 
else =[V  
break; Z\P&i#  
} ,[0rh%%j  
} <{b#nPc!,#  
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public void splitterStop() 00(#_($  
{ MbeO(Q  
bStop = true; Xw[|$#QKM  
} XveG#oyiU  
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} MnymV;y"  
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/* m;"dLUb  
**FileAccess.java {`CmE/`{  
*//文件访问(定位，写) E0Jk=cq  
package NetFox; .f]2%utHB  
import java.io.*; [ZkK)78}k  
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public class FileAccessI implements Serializable{ - d(RK_  
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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 G%RhNwm  
RandomAccessFile oSavedFile; S`?cs^?  
long nPos; gw);b)&mx  
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public FileAccessI() throws IOException +XN/ bT  
{ b".e6zev  
this("",0); WF0[/Y  
} F),wj8#~>-  
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public FileAccessI(String sName,long nPos) throws IOException .kkrU  
{ KQ(7%W  
oSavedFile = new RandomAccessFile(sName,"rw"); 1P+Te,I  
this.nPos = nPos; i VIpe  
oSavedFile.seek(nPos); b#[7A  
} IHlTp0?
  
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public synchronized int write(byte[] b,int nStart,int nLen) 51lN,VVD  
{ =/jCDY  
int n = -1; z4yV1  
try{ c_YP#U  
oSavedFile.write(b,nStart,nLen); j? P=}_Ru  
n = nLen; XKq}^M&gy  
} <X,0\U!lL  
catch(IOException e) 8~
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{ R7xEE7p
 
e.printStackTrace (); J|A:C[7 2  
} 4BgrG[l)  
zU$S#4/C  
hB)TH'R{:  
return n; Ei[>%Ah  
} 8bIwRVA2\  
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} 8 k%!1dyMB  
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/* 1SYBq,[])  
**SiteInfoBean.java 9L^:N)-  
*/ +Y  
package NetFox; )mVpJYt;  
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public class SiteInfoBean { ') -Rv]xe  
)+ss)LEC  
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private String sSiteURL; //Site's URL Os#
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private String sFilePath; //Saved File's Path J_=42aHO  
private String sFileName; //Saved File's Name M)1?$'Aq  
private int nSplitter; //Count of Splited Downloading File T@ecWRro  
uqg#(ADy?R  
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public SiteInfoBean() zz1e)W/  
{//nSplitter的缺省值为5 ]VU a$$  
//default value of nSplitter is 5 g,N"o72)  
this("","","",5); Mmu>&C\  
} 7u9!:}Tu  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) g^dPAjPQ  
{ zsZP\  
sSiteURL= sURL; $stBB  
sFilePath = sPath; hnbF}AD  
sFileName = sName; C/{tvY /o  
this.nSplitter = nSpiltter; eZ^-gk?  
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{IlX@qWr  
} `1
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public String getSSiteURL() !VJ5(b  
{ 9<ev]XaSl  
return sSiteURL; rprtp5Cg  
} xxN=,p  
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mz~aSbb|  
public void setSSiteURL(String value) 0DFxVH_xN  
{ mar BVFz~  
sSiteURL = value; eaI!}#>R+  
} P{-f./(JD  
F
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public String getSFilePath() KF#,Q  
{ 3'H 1T  
return sFilePath; y~cDWD<h  
} *Q@%<R  
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>lRa},5(  
public void setSFilePath(String value) ]ctlK'.  
{ n2JwZ?  
sFilePath = value; uD2v6x236  
} Ris5)*7  
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public String getSFileName() b@yGa%Gz@  
{ T@ [
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return sFileName; <3;Sq~^  
} ) DzbJ}  
,c%>M^d  
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public void setSFileName(String value) Zljj  
{ `nxm<~-\  
sFileName = value; =vv4;az X  
} xt%-<%s%f  
4EO,9#0  
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public int getNSplitter() .5',w"R  
{ f,?P1D\  
return nSplitter; ]&')#YO  
} Ighd,G-  
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public void setNSplitter(int nCount) )PRyDC-  
{ c teUKK.|)  
nSplitter = nCount; f\ wP}c'  
} d{UyiZm\  
} ^b{w\HZ  
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/* w+P
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**Utility.java u'o."J^&'  
*/ VFZ_Vw  
package NetFox; Wgt[ACioN  
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public class Utility { z8SrZ#mg  
/mb?C/CI  
;$Eg
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public Utility() *20$u% z2  
{ <_S>-;by  
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=AhXEu^  
} 6n{`t/  
~mqiXr8  
//线程睡眠 9Ytf7NpR  
public static void sleep(int nSecond) !^dvtv`K  
{ H5f>Q0jq  
try{ +Mb;;hb  
Thread.sleep(nSecond); uY,(3x  
} TNA?fm  
catch(Exception e) 1rr\l`  
{ t,mD{ENm&  
e.printStackTrace (); (RP"VEVR  
} B?qLXRv  
} $YM>HZe-  
Pa.D+  
//日志 OC$Y8Ofr  
public static void log(String sMsg) pg\Ylk"T  
{ Q3t9J"=1g  
System.err.println(sMsg); ZSKSMI%D  
} a&6e~E$K2  
9V]\,mD=  
y#'|=0vTvP  
public static void log(int sMsg) V^a]@GK:  
{ J2"n:  
System.err.println(sMsg); TG\3T%gH/s  
} 0] 'Bd`e  
} b<|l*\  
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}u=-Y'!#]  
/*  6j FD|  
**TestMethod.java -lKk.Y.}r  
*/ L'dR;T[;  
package NetFox; }uJH!@j  
!
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- J9K  
public class TestMethod { 'N?,UtG R  
>tfy\PY:  
'%@fW
:r~  
public TestMethod() ,O[HX?>  
{ ///xx/weblogic60b2_win.exe }B=`nbgIG7  
try{ ?U~9d"2=  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); #$&!)13  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); k_p4 f%9  
SiteFileFetch fileFetch = new SiteFileFetch(bean); xef@-%mcoy  
fileFetch.start(); 50:gk*hy  
} ;aJBx  
catch(Exception e){e.printStackTrace ();} S&y(A0M  
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} E2M|b  
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public static void main(String[] args) 8+ P)V4}  
{ >z'kCv
  
new TestMethod(); _e%jM[  
} Ccmo(W+0  
} }g1V6`8&  
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