http断点续传简单实现（java)

/* +pqM ^3t|y  
**SiteFileFetch.java OuIv e>8  
*/ #G3N(wV3  
package NetFox; 6Gn4aso
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import java.io.*; > 7`&0?  
import java.net.*; f"&Xr!b.h  
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public class SiteFileFetch extends Thread { }1+%_|Y-E  
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SiteInfoBean siteInfoBean = null; //文件信息Bean U=Bn>F}y\  
long[] nStartPos; //开始位置 >qT'z$  
long[] nEndPos; //结束位置 klWYuStZ  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 +
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long nFileLength; //文件长度 ;_<)JqUh  
boolean bFirst = true; //是否第一次取文件 JhR W[~  
boolean bStop = false; //停止标志 rVAL|0;3  
File tmpFile; //文件下载的临时信息 nv5u%B^  
DataOutputStream output; //输出到文件的输出流 -+U/Lrt>8  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 8 |h9sn;P  
public SiteFileFetch(SiteInfoBean bean) throws IOException oUW<4l  
{ u}H$-$jE  
siteInfoBean = bean; 2pyt&'NJua  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); \+qOO65/+  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ;7
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if(tmpFile.exists ()) i+M*J#'  
{ -.vDF?@G  
bFirst = false; 4f1D*id*`#  
read_nPos(); qJ[@:&:  
} 9EF~l9`'U  
else L~FTr  
{ ACBQ3  
nStartPos = new long[bean.getNSplitter()]; 1
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nEndPos = new long[bean.getNSplitter()]; rcbP$tvz  
} w.kCBDL  
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} 7S2C/f  
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public void run() WBppKj_M  
{ 5)lW  
//获得文件长度 RSWcaATZN  
//分割文件 fB#XhO  
//实例FileSplitterFetch !jh%}JJ  
//启动FileSplitterFetch线程 u39FN?<^  
//等待子线程返回 "zV']A>4H  
try{ ?=
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if(bFirst) F>Y9o-o2  
{ /BHepD}  
nFileLength = getFileSize(); Di??Q_$ak  
if(nFileLength == -1) f?0s &Xo  
{ k7bl'zic  
System.err.println("File Length is not known!"); lg/sMF>z\f  
} `B#Z;R  
else if(nFileLength == -2) -2NwF4VL  
{ h$h]%y  
System.err.println("File is not access!"); Ge}$rLu]0  
} Ob&W_D^=N  
else y' tRANxQ  
{ LC
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for(int i=0;i<nStartPos.length;i++) \K`jCsT  
{ q6[}ydV  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); P79R~m`  
} M4<+%EV}  
for(int i=0;i<nEndPos.length-1;i++) Xm[Czd]%  
{ ch,|1}bi  
nEndPos = nStartPos[i+1]; .S vyj  
} -Z?Ck!00  
nEndPos[nEndPos.length-1] = nFileLength; F RH&B5w  
} |>sv8/!  
} 44C+h    
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//启动子线程 H%.zXQ4}n  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; .98.G4J>  
for(int i=0;i<nStartPos.length;i++) ul}'{|4  
{ q,,j',8kq/  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), tyXl}$)y  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), dF2@q@\.+  
nStartPos,nEndPos,i); t.z$j  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); <3#<I)#  
fileSplitterFetch.start(); :,C%01bH|l  
} utd:&q|}  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), +{&+L0DfH~  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); y\_wWE  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", tP]q4i
 
nEndPos = " + nFileLength); ^-L{/'[8M  
// fileSplitterFetch[nPos.length-1].start(); ?N#[<kd  
6:RMU  
|e"/Mf[  
//等待子线程结束 OWV/kz5'H  
//int count = 0; +v1-.z  
//是否结束while循环 Dm4B  
boolean breakWhile = false; F^sw0 .b  
97x%2.\:  
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while(!bStop) s-5wbi.C  
{ RO(iHR3cA  
write_nPos(); :1BM=_WwI  
Utility.sleep(500); Zi3T~:0p:  
breakWhile = true; ^n71'MW  
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for(int i=0;i<nStartPos.length;i++) :C}Hy  
{ yam}x*O\xn  
if(!fileSplitterFetch.bDownOver) _>Ln@  
{ {jG.=}/Dk  
breakWhile = false; <rMv0y+r  
break; #`58F
.  
} "8_,tYAH  
} GXEcpc08  
if(breakWhile) 4@))OD^x  
break; 4f  jC  
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//count++; SauHFl8?  
//if(count>4) zkG>u,B}  
// siteStop(); ,]U[W  
} GRQ_+K  
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System.err.println("文件下载结束！"); 7%tR&F -u  
} THr8o V5  
catch(Exception e){e.printStackTrace ();} Dpj-{q7C  
} ]F_r6*<  
#ZF>WoC@e?  
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//获得文件长度 -XLo0  
public long getFileSize() o]p#%B?mZ  
{ pDmK  
int nFileLength = -1; l<n5gfJ  
try{ DOT=U _  
URL url = new URL(siteInfoBean.getSSiteURL()); 59K}  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Zr9d&|$  
httpConnection.setRequestProperty("User-Agent","NetFox"); W1<.OO\J  
?to1rFrU  
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int responseCode=httpConnection.getResponseCode(); 9[,s4sxH  
if(responseCode>=400) - &NQ\W  
{ 86#-q7aX  
processErrorCode(responseCode); 'FqEB]gu  
return -2; //-2 represent access is error km}MqBQl  
} A~XOK;sB  
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String sHeader; \{:%v#ZZ  
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for(int i=1;;i++) )]tvwEo  
{ 8T<@ @6`T  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); >6k}HrS1V  
//Utility.log(in.readLine()); "'~|}x1Uv  
sHeader=httpConnection.getHeaderFieldKey(i); =9fEv,Jk  
if(sHeader!=null) NA=#>f+U%  
{ x!`b'U\  
if(sHeader.equals("Content-Length")) zw,-.fmM#  
{ \a?K?v|8  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); RP(a,D|  
break; KS?mw`Nr  
} JxnuGkE0[#  
} l:q8Pg)  
else P3i^S_  
break; "*+\KPCU  
} TbMdQbj}  
} !5? m  
catch(IOException e){e.printStackTrace ();} _/ct=  
catch(Exception e){e.printStackTrace ();} pFEZDf}:  
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Utility.log(nFileLength); M5F(<,n;  
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return nFileLength;
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} |.Em_*VG  
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//保存下载信息（文件指针位置） G5Je{N8W  
private void write_nPos() 2YE7 23H=Z  
{ 3IGCl w(  
try{ :fRmUAK%  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Z^{+,$H@  
output.writeInt(nStartPos.length); ix^gA
ot  
for(int i=0;i<nStartPos.length;i++) E2kW=6VO>|  
{ ;*W=c  
// output.writeLong(nPos); TeKC} NW  
output.writeLong(fileSplitterFetch.nStartPos); H_Iim[v#  
output.writeLong(fileSplitterFetch.nEndPos); Jc`Rs"2  
} \Bt=bu>Z  
output.close(); gxI&f  
} ~:T3|  
catch(IOException e){e.printStackTrace ();} r}ZLf  
catch(Exception e){e.printStackTrace ();} c6t2Q6zV  
} >6OCKl  
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//读取保存的下载信息（文件指针位置） ``+c`F?5  
private void read_nPos() cES;bwQ  
{ $pjf#P8U  
try{ ]{(l;k9=e  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); m dC`W&r  
int nCount = input.readInt(); i
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nStartPos = new long[nCount]; Y 5Qb4Sa  
nEndPos = new long[nCount]; z<n"{%  
for(int i=0;i<nStartPos.length;i++) CdDH1[J  
{ =x=1uXQv5  
nStartPos = input.readLong(); nrF%wH/5  
nEndPos = input.readLong(); T_uNF8Bh  
} O;UiYrXU  
input.close(); 8n;kK?  
} @55bE\E?@  
catch(IOException e){e.printStackTrace ();} ^I@ey*$  
catch(Exception e){e.printStackTrace ();} ]Mn&76fu  
} `<S/?I8  
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private void processErrorCode(int nErrorCode) mr@_%U  
{ ftO+.-sm<  
System.err.println("Error Code : " + nErrorCode); {-o7w0d_  
} D}mo\  
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//停止文件下载 4Y`! bT`  
public void siteStop() c=jcvDQ6W  
{ NR;q`Xe-  
bStop = true; '&N: S-  
for(int i=0;i<nStartPos.length;i++) 2_Pz^L  
fileSplitterFetch.splitterStop(); ^a086n  
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} axWM|Bw<+  
} mG>T`c|r3  
//负责部分文件的抓取 =t@:F
 
**FileSplitterFetch.java h~,x7]
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*/ Bh\ [CY  
package NetFox; g!p+rq_f  
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import java.io.*; 8o!  
import java.net.*; )WaX2uDA?  
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public class FileSplitterFetch extends Thread { pZc9q8j3  
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String sURL; //File URL bs:C1j\&  
long nStartPos; //File Snippet Start Position 3Qqnw{*  
long nEndPos; //File Snippet End Position -X`~;=m>U  
int nThreadID; //Thread's ID gcX5Q^`a=  
boolean bDownOver = false; //Downing is over }W- K  
boolean bStop = false; //Stop identical d8xk&za  
FileAccessI fileAccessI = null; //File Access interface \7|s$ XQ\  
7'-)/Pk  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException
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{ +#|'|}j  
this.sURL = sURL; ;6DR.2}?>  
this.nStartPos = nStart; M
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this.nEndPos = nEnd; Zr
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nThreadID = id; 0lLr[  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 N%|^;4}k  
} 0z#l0-NdQ  
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public void run() ?3]h~(=  
{ I>N-95  
while(nStartPos < nEndPos && !bStop) *D,v>(  
{ [,\'V0  
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try{ sq8tv]  
URL url = new URL(sURL); N&R '$w  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); U92B+up-  
httpConnection.setRequestProperty("User-Agent","NetFox"); 27h/6i3  
String sProperty = "bytes="+nStartPos+"-"; t9KH|y  
httpConnection.setRequestProperty("RANGE",sProperty); Up]VU9z  
Utility.log(sProperty); a(Gk~vD;"  
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InputStream input = httpConnection.getInputStream(); :vn0|7W4  
//logResponseHead(httpConnection); UQC'(>.}  
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byte[] b = new byte[1024]; asm[-IB2u  
int nRead; \GjXsR*b5  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ,Ut!u)  
{ #Pe\Z/  
nStartPos += fileAccessI.write(b,0,nRead); kphy7>Km  
//if(nThreadID == 1) <a4
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// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); /ieu)m:2  
} ^L*VW gi9  
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Utility.log("Thread " + nThreadID + " is over!"); z1}tC\9'%  
bDownOver = true; 4YU1Kr4  
//nPos = fileAccessI.write (b,0,nRead); @O  @|M'  
} @&am!+z  
catch(Exception e){e.printStackTrace ();} aT`02X  
}  6Dr$
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} U 8qKD  
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2uI`$A:  
//打印回应的头信息 ie$fMBIq  
public void logResponseHead(HttpURLConnection con) e!:?_z."  
{ .@x"JI>;  
for(int i=1;;i++) 'vf,T4uQ"  
{ PBPJ/puW  
String header=con.getHeaderFieldKey(i); #b]}cwd!  
if(header!=null) ;6\Ski0=l  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); `9G$p|6  
Utility.log(header+" : "+con.getHeaderField(header)); +v`^_  
else Z3u""oM/  
break; H|(*$!~e  
} CwCo"%E8}  
} Bv |jo&0n  
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public void splitterStop() \8C*O{w  
{ egIS rmL+X  
bStop = true; 34O+#0<y~  
} f|[5&,2<  
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} 'nmYB:&!  
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/* $48[!QE  
**FileAccess.java >Y*iy  
*//文件访问(定位，写) !O%f)v?  
package NetFox; P[J qJi/H  
import java.io.*; XQ|j5]  
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public class FileAccessI implements Serializable{ .q;RNCUt  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 802]M  
RandomAccessFile oSavedFile; D?&w:C\&@z  
long nPos; :h](;W>H  
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public FileAccessI() throws IOException ~9{-I{=  
{ 2Dwt4V  
this("",0); -7Y'6''~W.  
} 9M-]~.O  
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public FileAccessI(String sName,long nPos) throws IOException 5SP
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{ 0ju wDd  
oSavedFile = new RandomAccessFile(sName,"rw"); }M"'K2_Z  
this.nPos = nPos; 0"D?.E"$r  
oSavedFile.seek(nPos); #ui%=ja[:~  
} YJtOdgG|q  
jWb\"0)  
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public synchronized int write(byte[] b,int nStart,int nLen) y^Xxa'y  
{ $K>d\{@+7  
int n = -1; a!6OE"?QQ  
try{ iz|9a|k6x  
oSavedFile.write(b,nStart,nLen); *^$N$t/2  
n = nLen; e715)_HD  
} 66y,{t
  
catch(IOException e) ^SL}wC x  
{ (UiH3Q9C]%  
e.printStackTrace (); g5TLX&Bd  
} 3T#3<gqM[  
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return n; 7$!Bq#  
} uS+b* :  
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} 0BU:(o
&  
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/* XajY'+DIsz  
**SiteInfoBean.java Jv$2wH  
*/ Sv]"Y/N  
package NetFox; cF>;f(X  
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public class SiteInfoBean { oFx gR9  
f\%X7.  
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private String sSiteURL; //Site's URL u*YuU%H=  
private String sFilePath; //Saved File's Path L bK1CGyA  
private String sFileName; //Saved File's Name K {N;k-  
private int nSplitter; //Count of Splited Downloading File hQRc,d6x5  

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public SiteInfoBean() Y&:\s8C  
{//nSplitter的缺省值为5 }jy7,+  
//default value of nSplitter is 5 Z-r0 D  
this("","","",5); g
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} N pIlQaMo4  
;]ZHD$g  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) E52:c]<'m  
{ ZCq\Zk1O&  
sSiteURL= sURL; ,}xC) >  
sFilePath = sPath; 5Szo5  
sFileName = sName; Hrc
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this.nSplitter = nSpiltter; l~>rpG  
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} fwGz00C/U  
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public String getSSiteURL() $7ME a"a  
{ (Y?yGq/  
return sSiteURL; 6I'VXdeN  
} @n y{.s+  
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public void setSSiteURL(String value) u(Q(UuI  
{ _!T$|,a  
sSiteURL = value; p5 PON0dS  
} Z-=7QK.\{  
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+.Ukzu~s  
public String getSFilePath() P>cJ~FM  
{ Lgw@y!Llij  
return sFilePath; kxiyF$ 9  
} (W6\%H2u  
m^&mCo,  
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public void setSFilePath(String value) Gf$>!zXr  
{ ojI"<Q~g  
sFilePath = value; v*p)"J *  
} &~6O;}\  
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public String getSFileName() G&B}jj  
{ 
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return sFileName; ZI*A0_;L  
} `9)2nkJk'z  
lP &%5y;  
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public void setSFileName(String value) , 0ja_  
{ d:ajD  
sFileName = value; uy28=BE  
} 8i~'~/x  
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public int getNSplitter() k3eN;3#&  
{ zm.sX~j  
return nSplitter; U*l>8  
} J*k=|+[  
>I;#BE3  
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public void setNSplitter(int nCount) eJdQ7g[>  
{ 7Et(p'  
nSplitter = nCount; =I3U.^:  
} BuO J0$  
} ^@cX0_  
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/* D($UbT-v  
**Utility.java *m/u3.\  
*/ PhdL@Mr  
package NetFox; BAed
[  
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public class Utility { 5.;$9~d  
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public Utility() vIv3rN=5vB  
{ rI$10R$+H  
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} ,o6: V]a  
7hE=+V8  
//线程睡眠 H*<dte<  
public static void sleep(int nSecond) U}TQXYAg  
{ wYM{x!D  
try{ p =O1aM  
Thread.sleep(nSecond); NX/)Z&Fx:  
} }e|]G,NZO  
catch(Exception e) `&
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{ ;f*xOdi*k  
e.printStackTrace (); ~Dh}E9E:
 
} |EA1+I.&x  
} %ua5T9H Z  
$^GnY7$!>  
//日志 8`<Gp
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public static void log(String sMsg) :RG6gvz  
{ p8bTR!rvz  
System.err.println(sMsg); TR7TF]itb  
} $l0w{m!P  
EPf
VS  
ZmF32Ir  
public static void log(int sMsg) 6f1Y:qK'@  
{ (b5af_ c  
System.err.println(sMsg); 3_:k12%p  
} Ue%5 :Sdr  
} ]>j_ Y,  
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/* -hfY:W`Dz  
**TestMethod.java NyN
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*/ :a`m
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package NetFox; w Nnb@  
s)=7tHoqB)  
^4i3#}  
public class TestMethod { WR%iUO40  
|'#NDFI>}  
-JkO[IF  
public TestMethod() %&NK|M
+n  
{ ///xx/weblogic60b2_win.exe ^hJ,1{o  
try{ efm<bJB2  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); C\K--  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); X[}%iEWzT  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ponvi42u  
fileFetch.start(); (d\bSo$]  
} Vh&KfYY  
catch(Exception e){e.printStackTrace ();} ,@MPzpH  
%hh8\5l.:  
~CscctD{;  
} ?U[AE -*  
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6
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public static void main(String[] args) irS62Xe  
{ [0emOS  
new TestMethod(); 75ob1h"  
}  (w fZ!  
} =XB)sC%  
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