http断点续传简单实现（java)

/* yXCH
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**SiteFileFetch.java X?'pcYSL  
*/ wT+\:y  
package NetFox; rw[Ioyr-  
import java.io.*; pz

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import java.net.*; JD]uDuE  
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public class SiteFileFetch extends Thread { vywpX^KPv  
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SiteInfoBean siteInfoBean = null; //文件信息Bean +77B656  
long[] nStartPos; //开始位置 b[~
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long[] nEndPos; //结束位置 NJg )S2]7  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 4-oaq'//BT  
long nFileLength; //文件长度 x!n8Wx  
boolean bFirst = true; //是否第一次取文件 ]$I}r= Em  
boolean bStop = false; //停止标志 /z: mi  
File tmpFile; //文件下载的临时信息 =G`g-E2  
DataOutputStream output; //输出到文件的输出流 dEZlJo@J  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ;KT5qiqYH  
public SiteFileFetch(SiteInfoBean bean) throws IOException &W{v(@  
{ wJh/tb=$o  
siteInfoBean = bean; ?HeUU  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); <,y> W!  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Y
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if(tmpFile.exists ()) Yw_!40`  
{ ZWQ/BgKB  
bFirst = false; W"&,=wvg2  
read_nPos(); [OR"9W&  
} d-TpY*v  
else (
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{ 6i%Xf i  
nStartPos = new long[bean.getNSplitter()]; .sD=k3d  
nEndPos = new long[bean.getNSplitter()]; ~nApRC)0  
} S1U[{R?,  
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} KtHkLYOCG  
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public void run() S q{@4F}d  
{ -_XTy!I  
//获得文件长度 /y(0GP4A  
//分割文件 q}W})  
//实例FileSplitterFetch
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//启动FileSplitterFetch线程 ~ 7<M6F  
//等待子线程返回 I+ Y{_yw"f  
try{ oXUb_/  
if(bFirst) L+}<gQJ(  
{ LL==2KNUo  
nFileLength = getFileSize(); w/*m_O\!  
if(nFileLength == -1) fElFyO
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{ nkf7Fq}  
System.err.println("File Length is not known!"); 2+ywl}9  
} ?hViOh$.  
else if(nFileLength == -2) lSc=c-iOv  
{ :aH5=@[!y  
System.err.println("File is not access!"); gFsqCx<q  
} Eihn%Esa  
else KD?b|y@  
{ <T&v\DN  
for(int i=0;i<nStartPos.length;i++) '.&Y)A6!  
{ D}Sww5ZmP  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); /Q_Dd  
} <. *bJ  
for(int i=0;i<nEndPos.length-1;i++) u08QE,
 
{ h J0U-m  
nEndPos = nStartPos[i+1]; $tej~xZK  
} KC)}Mzt6_  
nEndPos[nEndPos.length-1] = nFileLength; r-.>3J  
} YrV@k*O*  
}
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E;[Uhh|78!  
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//启动子线程 'by+hXk  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; # 1dg%  
for(int i=0;i<nStartPos.length;i++) AQmHa2P  
{ _,/~P)  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), @w`wJ*I4,  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), _*MK"  
nStartPos,nEndPos,i); EX#AJ>?V(  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ]Y!x7  
fileSplitterFetch.start(); eze%RjO}  
} 2=/-,kOL_  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(),
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Qj*.Z4ue  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", xF@&wg  
nEndPos = " + nFileLength); `.J17mQe"  
// fileSplitterFetch[nPos.length-1].start(); >H ?k0M`L  
A\#z<h[>  
1GK>&;  
//等待子线程结束 3&nN;4~Zx6  
//int count = 0; 2;0eW&e   
//是否结束while循环 N$
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boolean breakWhile = false; : ]
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} `5k^J$x  
tym:C7v%~  
while(!bStop) 5n{d jP  
{ lRb>W31"  
write_nPos(); Z&U:KrFH  
Utility.sleep(500); M&/%qF15  
breakWhile = true; MX8|;t  
@`dlhz  
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for(int i=0;i<nStartPos.length;i++) tRZ4\Bu  
{ K/K-u  
if(!fileSplitterFetch.bDownOver) m uy^>2p  
{ Q$v00z]f*  
breakWhile = false; -J8Hsqf@  
break; ixSr*+  
} =*"8N-FU  
} >0W P:-\*  
if(breakWhile) %qiVbm0  
break; +vaA P=  
8'%m
!  
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//count++; ][ IOlR  
//if(count>4) sRA2O/yKCE  
// siteStop(); N9-7YQ`D  
} m|F1_Ggz  
^6z"@+;*  
`;J`O02  
System.err.println("文件下载结束！"); Y
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} ,
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catch(Exception e){e.printStackTrace ();} !ltq@8#_|  
} fBj)HoHQW  
>36,lNt  
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//获得文件长度 6-fv<Pn  
public long getFileSize() R$8{f:Pj  
{ ,(pp+hNq  
int nFileLength = -1; 3h d30o  
try{ 6#!CBY^{  
URL url = new URL(siteInfoBean.getSSiteURL()); $`55
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); f!`?_  
httpConnection.setRequestProperty("User-Agent","NetFox"); N)GHQlgH  
G(TFv\`vH  
9$HBKcO  
int responseCode=httpConnection.getResponseCode(); )c{>@WM~  
if(responseCode>=400)
rpK&OR/  
{ )N8b
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processErrorCode(responseCode); h]s~w  
return -2; //-2 represent access is error {;u,04OVK  
} PPr Pj^%z=  
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String sHeader; kuD$]A Q`&  
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for(int i=1;;i++) @,TIw[p  
{ fy4zBI@  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Q_|}~4_+  
//Utility.log(in.readLine()); 8c+V$rH_  
sHeader=httpConnection.getHeaderFieldKey(i); "(7y%TFt:  
if(sHeader!=null) A*?PH`bY  
{ d\l{tmte  
if(sHeader.equals("Content-Length")) Syy{ ^Ae}  
{ rZJJ\ , |  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); j2<+[h-  
break; ~TEn +  
} .R)P |@z L  
} m^}|LB:5  
else Cl<!S`  
break; 3HpqMz  
} M7cD!s@'I  
} r)pt(*KHo  
catch(IOException e){e.printStackTrace ();} Sb/?<$>  
catch(Exception e){e.printStackTrace ();} Sv{n?BYq  
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:5,~CtF5 `  
Utility.log(nFileLength); 95z|}16UK  
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return nFileLength; '-YiV  
} B_Q{B|eEt&  
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 4d5c]%  
//保存下载信息（文件指针位置） aC\f;&P>  
private void write_nPos() ;v@
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{ 6r<a
  
try{ q
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output = new DataOutputStream(new FileOutputStream(tmpFile)); Zek@xr;]  
output.writeInt(nStartPos.length); #dUKG8-HJ  
for(int i=0;i<nStartPos.length;i++) {MUiK5:  
{
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// output.writeLong(nPos); BX0lk  
output.writeLong(fileSplitterFetch.nStartPos); $h{m")]  
output.writeLong(fileSplitterFetch.nEndPos); :^3)[.m  
} KD &nLm!  
output.close(); cQj`W *  
} I"88O4\@  
catch(IOException e){e.printStackTrace ();} +9b{Y^^~T  
catch(Exception e){e.printStackTrace ();} KHML!f=mu  
} I.jqC2G  
S@HC$  
uI7n{4W*x  
//读取保存的下载信息（文件指针位置） w~b:9_reY  
private void read_nPos() v"o"W[  
{ \mc0fY  
try{ >0{}tRm-P&  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); FtIcA"^N  
int nCount = input.readInt(); U.Mfu9}#:  
nStartPos = new long[nCount]; )OV0YfO  
nEndPos = new long[nCount]; f[k#Znr  
for(int i=0;i<nStartPos.length;i++) iH }-  
{ q5SPyfE[  
nStartPos = input.readLong(); *=!e,  
nEndPos = input.readLong(); .P)lQk\  
} [ ulub|  
input.close(); pXSShU#  
} e c&Y2  
catch(IOException e){e.printStackTrace ();} 4|`>}Nu  
catch(Exception e){e.printStackTrace ();} +twoUn{#  
} ?7aZU  
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private void processErrorCode(int nErrorCode) W\~^*ny P6  
{ H`CID*Ji  
System.err.println("Error Code : " + nErrorCode); V%oZT>T3  
} 0hemXvv1  
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{-\U)&6#v  
//停止文件下载 MN
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public void siteStop() q*&R&K;q
 
{ ~(^P(  
bStop = true; 2IJK0w@  
for(int i=0;i<nStartPos.length;i++) =b%}x >>  
fileSplitterFetch.splitterStop(); \;X7DK2  
+lx&$mr?  
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} 4b2d(x)0X  
} kXSX<b<%  
//负责部分文件的抓取 uAn}qrqE9  
**FileSplitterFetch.java ,2S!$M  
*/ ]c/E7|0Q  
package NetFox; 2FIL@f|\7z  
q Q\j  
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import java.io.*; la3B`p  
import java.net.*; )\akIA  
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public class FileSplitterFetch extends Thread {
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String sURL; //File URL 5?7AzJl>  
long nStartPos; //File Snippet Start Position Du+W7]yCl  
long nEndPos; //File Snippet End Position %\m"Yi]  
int nThreadID; //Thread's ID ;,&cWz  
boolean bDownOver = false; //Downing is over 3v8LzS3@  
boolean bStop = false; //Stop identical vgwpuRL5b  
FileAccessI fileAccessI = null; //File Access interface YMX9Z||  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException '#'noB;,  
{ 4VJUu`[  
this.sURL = sURL; o!M8V ^
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this.nStartPos = nStart; 4Z)s8sDKW  
this.nEndPos = nEnd; ~bLx2=-"  
nThreadID = id; p%Z:SZZ  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 +=3=%%?C  
} ;g|Vt}a&4  
<Y]LY_(  
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public void run() sK}AS;:  
{ 'C[tPP  
while(nStartPos < nEndPos && !bStop) 4ijtx)SA  
{ N''QQBUD  
Hb)FeGsd).  
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try{ /{^k8 Q  
URL url = new URL(sURL); @Vm*b@  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); AFrJzh:V[  
httpConnection.setRequestProperty("User-Agent","NetFox"); 9bM\ (s/  
String sProperty = "bytes="+nStartPos+"-"; <Riz!(G  
httpConnection.setRequestProperty("RANGE",sProperty); 5C Dk5B_  
Utility.log(sProperty); K zWo}tT  
&`r/+B_W  
uz8LF47@:-  
InputStream input = httpConnection.getInputStream(); n#(pT3&  
//logResponseHead(httpConnection); U+Y(:  
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byte[] b = new byte[1024]; 9wvlR6z;u  
int nRead; c[h~=0UtJ  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 6mM9p)"$  
{ * ,hhX psa  
nStartPos += fileAccessI.write(b,0,nRead); cLtVj2Wb  
//if(nThreadID == 1) /LD3Bb)O  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); t3;Zx+Br  
} R;< q<i_l  
2Rk}ovtD[  
=oBpS=<7  
Utility.log("Thread " + nThreadID + " is over!"); KdVKvs[  
bDownOver = true; X6HaC+P  
//nPos = fileAccessI.write (b,0,nRead); 02-ql F@i  
} MEDh  
catch(Exception e){e.printStackTrace ();} /F0q8j0  
} PYkhY;*  
} UL+Txc  
|+#Zuq  
I?e5h@uE  
//打印回应的头信息 Tgdy;?  
public void logResponseHead(HttpURLConnection con) -k'<6op  
{ G@8)3 @  
for(int i=1;;i++) H[=\_X1o(  
{ G3.a
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String header=con.getHeaderFieldKey(i); `w@:h4f  
if(header!=null) /"{d2  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); rAenxZ,tF  
Utility.log(header+" : "+con.getHeaderField(header)); hG1:E:}  
else 86ao{l6lC  
break; .U1wVIM  
} \x<8   
} g)X3:=['  
/fI}QY1  
1dH|/9  
public void splitterStop() ^? fOccfQ{  
{ 8w0~2-v.?V  
bStop = true; %8'8XDq^8  
} VBhUh~:Om  
oTw!#Re)  
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} DHO]RRGV  
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<FT7QO$I  
/* yJA~
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**FileAccess.java +}:Z9AAMy  
*//文件访问(定位，写) S$mv(C  
package NetFox; !=[Y yh  
import java.io.*; q}{E![ZTu  
) c@gRb~  
&jqaW2  
public class FileAccessI implements Serializable{ VvhfD2*T  
1Bh"'9-!JT  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ho\1[xS  
RandomAccessFile oSavedFile; fM=o?w6v  
long nPos; MxE]EJZ  
`|t,Uc|7!  
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public FileAccessI() throws IOException &YhAB\Rw  
{ }k^uup*{  
this("",0); p Cz6[*kC  
} ]J7qs
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(v]%kXy/G  
3?93Pj3oPt  
public FileAccessI(String sName,long nPos) throws IOException 3[m~-8  
{ @r"\bBi  
oSavedFile = new RandomAccessFile(sName,"rw"); mqSVd^  
this.nPos = nPos; }lZEdF9GhG  
oSavedFile.seek(nPos); GBJLB  
} cO?*(e1m=  
QPlU+5Cx  
i<QDV W9  
public synchronized int write(byte[] b,int nStart,int nLen) "[)G{VzT  
{ egoR])2>  
int n = -1; "{0G,tdA  
try{ Ot=>~(u0  
oSavedFile.write(b,nStart,nLen); .3 EZk86  
n = nLen; ;n&95t1$  
} 8_Oeui(i  
catch(IOException e) s^kG]7  
{ &Vlno*  
e.printStackTrace (); eg[EFI.h  
} (:oF\  
^~4]"J};M  
N?\X2J1  
return n; (Y1*Bs[l  
} <A3%182  
ni;_Un~  
?ANWI8'_j  
} ~f<']zXv  
~
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8Z  
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/* 15:9J
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**SiteInfoBean.java 66=[6U9 *  
*/ %4~"$kE  
package NetFox; Jqoo&T")  
Yh<F-WOo2  
!(d]f0  
public class SiteInfoBean { h&"9v~  
V)$!WPL@  
C5~#lNC  
private String sSiteURL; //Site's URL a&s34Pd  
private String sFilePath; //Saved File's Path kWzp*<lWe  
private String sFileName; //Saved File's Name ~ 'ZwD/!e  
private int nSplitter; //Count of Splited Downloading File ~Ntk-p  
*>m[ZJd%=  
g/GI'8EMj  
public SiteInfoBean() y0%@^^-Ru  
{//nSplitter的缺省值为5 } z'Jsy[s  
//default value of nSplitter is 5 [LVXXjkFI  
this("","","",5); |$WH
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} 9*"  
-]3K#M)s  
pqG>|#RG  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) x@#>l8k?  
{ ?2@^O=I  
sSiteURL= sURL; jWdviS9&g  
sFilePath = sPath; h.<f%&)F  
sFileName = sName; d`sZ"8}j  
this.nSplitter = nSpiltter; vC]X>P5Px  
*byUqY3(
 
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} W;u.@I&  
\Ec<ch[)c  
sI,cX#h&Y  
public String getSSiteURL() tU4#7b:Y  
{ ( 5LCy?-6  
return sSiteURL; P1F-Wy1  
} -}7$;QK&a  
dL42)HP5  
{"o9pIh{~  
public void setSSiteURL(String value) *@rA7zPFf  
{ ]d
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sSiteURL = value; ^ :VH?I=  
} CHnclT  
K V5 '-Sv1  
W8W7<ml0A  
public String getSFilePath() >a"J);p  
{ !vz'zy)7  
return sFilePath; hFV,FBsAO  
} rS@/@jKZE  
[6VB&   
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public void setSFilePath(String value) 1/$PxQ  
{ -2hirA<^  
sFilePath = value; .n\JY;"  
} xe@e#9N$  
@eYpARF  
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public String getSFileName() CE"/&I  
{ .s{"NqRA  
return sFileName; x`6MAZ  
} BlJiHz!  
p4T$(]7  
4\z@Evm  
public void setSFileName(String value) h&4s%:_4  
{ LL<xyg
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sFileName = value; t$BjJ -G  
} x?AG*' h&  
yY VR]HH  
.fWy\r0  
public int getNSplitter() f:-)S8OJ  
{ sH6;__e  
return nSplitter; (.-4Jn  
} :jTSOd[r  
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public void setNSplitter(int nCount) $>)0t@[f  
{ 7. F'1oEf  
nSplitter = nCount; \ eHOHHAGW  
} ZSf &M  
} ^50dF:V(1  
TFXBN.?9T  
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/* 'jt7H{M  
**Utility.java 9E7G%-  
*/ t}+/GSwT  
package NetFox; TpU\IQ  
mCO1,?  
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public class Utility { P~ObxY|  
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"L3mW=!*  
public Utility() LS~at.3zX  
{ Ph3;;,v '  
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F`g(vD>  
} H07\z1?.K  
yGR{-YwU!  
//线程睡眠 *OLqr/
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public static void sleep(int nSecond) 1Q@]b_"Xh  
{ ImN'o4vo  
try{ /8GdCac  
Thread.sleep(nSecond); /1OCK=  
} c~<;}ve^z  
catch(Exception e) J&8KIOz14Z  
{ -,8LL@_  
e.printStackTrace (); 8lusKww  
} SAP/jD$5]>  
} N{%7O
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Vk{
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//日志 zYzV!s2^  
public static void log(String sMsg) 6n]+(=  
{ 3U<m\A1  
System.err.println(sMsg); G)amng/  
}  sS-dHa  
9q"kM  
4l 67B]o  
public static void log(int sMsg)
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{ <YvXyIs  
System.err.println(sMsg); E+]}KX:  
} zud_BOq{f  
} Im;%.J  
;e?M;-  
:[CV_ME.;  
/* }$_@yt<{W@  
**TestMethod.java 8?Zhh.  
*/ ]PS`"o,pF$  
package NetFox; 9@|52dz%  
5%jhVys23  
.!3e$mhV  
public class TestMethod { zsp%Cz7T  
%7ngAIg  
hTDK[4e  
public TestMethod() {s8c@-'  
{ ///xx/weblogic60b2_win.exe w;lpJB\  
try{ /h>g-zb  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); z:\9t[e4  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ZDW9H6ux  
SiteFileFetch fileFetch = new SiteFileFetch(bean); i.mv`u Dm  
fileFetch.start(); M@ U>@x;  
} ?c#s}IH  
catch(Exception e){e.printStackTrace ();} -Q20af-  
1'&.6{)P  
Y5aG^wE[:  
} JI>Y?1i0O  
$cSUB  
}a;xs};X;  
public static void main(String[] args) R1zt6oY  
{ $7q3[skH  
new TestMethod(); 4aHogheg  
} neFwxS?  
} oxxuw Dcl  
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