http断点续传简单实现（java)

/* O`0\f8/.?  
**SiteFileFetch.java _*u$U  
*/ $NwPGy?%  
package NetFox; z v:o$2Z  
import java.io.*; )W!\D/C+  
import java.net.*;  J?qikE&  
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public class SiteFileFetch extends Thread { }n?D#Pk,  
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SiteInfoBean siteInfoBean = null; //文件信息Bean o
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long[] nStartPos; //开始位置 3Hhu]5  
long[] nEndPos; //结束位置 iq3TP5%i  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 \qB.>f"%p|  
long nFileLength; //文件长度 +pbP;zu  
boolean bFirst = true; //是否第一次取文件 GT-ONwVDq  
boolean bStop = false; //停止标志 VN]"[  
File tmpFile; //文件下载的临时信息 UMlvu?u2p1  
DataOutputStream output; //输出到文件的输出流 dIk9C|-.  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） Ksvk5r&y  
public SiteFileFetch(SiteInfoBean bean) throws IOException O2oF\E_6  
{ $!\Z_:  
siteInfoBean = bean; }}4uLGu)  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); i6xzHfaYG  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); G3.\x_;k  
if(tmpFile.exists ()) k3&/Ei5  
{ /=:Fw}vt  
bFirst = false; HnY.=_G  
read_nPos(); e@g=wN"@  
} !+n'0{  
else >,c'Z<TM  
{ OZ2faf  
nStartPos = new long[bean.getNSplitter()]; 6Q}>=R^h  
nEndPos = new long[bean.getNSplitter()]; 921s'"  
} cC TTjx{  
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} XZj3x',;  
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public void run() zz-X5PFn  
{ 8n/[oDc]  
//获得文件长度 Nd**":i$  
//分割文件 M#xol/)h  
//实例FileSplitterFetch UW-`k1  
//启动FileSplitterFetch线程 ^'4I%L"  
//等待子线程返回 -z>m]YDH  
try{ SHqz&2u  
if(bFirst) N`7+]T  
{ L:Me  
nFileLength = getFileSize(); q`L}\}o  
if(nFileLength == -1) r9~IR  
{ z=qxZuFkDs  
System.err.println("File Length is not known!"); rz5@E  
} vw/GAljflu  
else if(nFileLength == -2) pm:#@sl  
{ [q(}~0{"-  
System.err.println("File is not access!"); kDc/]Zb%  
} VoNk.h"T  
else K9S(Xip  
{ XknbcA|  
for(int i=0;i<nStartPos.length;i++) |i- S}M  
{ 1N+ju"2R  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); fP{IW`t}]  
} py9`q7F  
for(int i=0;i<nEndPos.length-1;i++) >&)|fV&4  
{ g7Z3GUCGL  
nEndPos = nStartPos[i+1]; Hx ojxZwm  
} 6V-JyTcxGI  
nEndPos[nEndPos.length-1] = nFileLength; j +Ro?  
} /@6T~XY M  
} UZu.B!4  
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p}q]G
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//启动子线程  pwo @ S"  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; - 4B&{P  
for(int i=0;i<nStartPos.length;i++) 2z9N/SyN  
{ %wIb@km  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), -Vj112 fI  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), TR!7@Mu3  
nStartPos,nEndPos,i); Enqs|fkbN  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); *%2,= p  
fileSplitterFetch.start(); ?P Mi#H  
} 3q`Uq`t4mR  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 57:27d0y  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); T$tO[QR/  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 4JGU`L:~  
nEndPos = " + nFileLength); )D ':bWP  
// fileSplitterFetch[nPos.length-1].start(); h~k+!\  
lF)k4 +M  
13/U4-%b2  
//等待子线程结束 FyRr/0C>  
//int count = 0; u(4o#m  
//是否结束while循环 V#V<Kz  
boolean breakWhile = false; c~ Q5A  
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while(!bStop)
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{ ]wV_xZ)l^A  
write_nPos(); ]?~[!&h  
Utility.sleep(500); "qw.{{:tf  
breakWhile = true; [ejl #'*5  
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for(int i=0;i<nStartPos.length;i++) &u~%5
;  
{ -
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if(!fileSplitterFetch.bDownOver) .$ 5*v  
{ ~{[,0,lWU  
breakWhile = false; :bz;_DZP  
break;
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} Klqte*!  
} zCSLV>.F  
if(breakWhile) ilFS9A3P  
break; tj[-|h  
,w7ZsI4:[  
!6`&0eY  
//count++; H;RgYu2J  
//if(count>4) t&rr;W]  
// siteStop(); jQpG7H  
} k]yv#Pa  
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System.err.println("文件下载结束！"); ]}nX$xy  
} (z X&feq  
catch(Exception e){e.printStackTrace ();} C<N7zMwT  
} Px?0)^"2  
0<]]q[pr  
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//获得文件长度 ]0;,M  
public long getFileSize() wO"ezQ  
{ =+VI{~.|}  
int nFileLength = -1; &_$xMM,X  
try{ K=!?gd!Vw  
URL url = new URL(siteInfoBean.getSSiteURL()); !&Us^Q^  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); \D}$foHg  
httpConnection.setRequestProperty("User-Agent","NetFox"); 4j~WrdI*  
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int responseCode=httpConnection.getResponseCode(); ]V
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if(responseCode>=400) xO;Qr.3PX  
{  fG|+!  
processErrorCode(responseCode);  Rlx  
return -2; //-2 represent access is error @wa<nYd  
} qnf\K
}  
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String sHeader; .jRv8x b
 
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for(int i=1;;i++) QjyJmW("Z  
{ SNtOHTQ  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ()
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//Utility.log(in.readLine()); <"x *ZT  
sHeader=httpConnection.getHeaderFieldKey(i); Owm2/  
if(sHeader!=null) ;Yn_*M/*  
{ P!~B07y  
if(sHeader.equals("Content-Length")) u|\K kk  
{ @1)C3(=A  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 7kQ,D,c'  
break; 8Tm/gzx  
} mcSZ1d~,(  
} luV_  
else FSS~E [(DL  
break; J*]JH{  
} =8x-+u5}rK  
} M
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catch(IOException e){e.printStackTrace ();} .;NoKO7)  
catch(Exception e){e.printStackTrace ();}  h]?[}&  
((tWgSZ3  
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Utility.log(nFileLength); T2i\S9X  
[
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return nFileLength; 2Jn?'76`  
} a|@1RH>7H  
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//保存下载信息（文件指针位置） \t]aBT,  
private void write_nPos() JL&ni]m  
{ 'pl){aL`@u  
try{ 4t0-L]v4.*  
output = new DataOutputStream(new FileOutputStream(tmpFile)); j0IuuJ+  
output.writeInt(nStartPos.length); &}vc^
io  
for(int i=0;i<nStartPos.length;i++) B~/ejC!  
{ &3'zG)  
// output.writeLong(nPos); ?1lx8+  
output.writeLong(fileSplitterFetch.nStartPos); gj1l9>f>]a  
output.writeLong(fileSplitterFetch.nEndPos); 1A/li%  
} D[CEg2$y  
output.close(); ]e]hA@4  
} _D."KU|  
catch(IOException e){e.printStackTrace ();} ;X[23A{
 
catch(Exception e){e.printStackTrace ();} R=s^bYdoy  
} v9vY#W  
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-vBk,;^>  
//读取保存的下载信息（文件指针位置） ({p@Ay  
private void read_nPos() ,v*<yz/  
{ ED R*1!d  
try{ d)jX%Z$LC  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); +0FmeM&`h_  
int nCount = input.readInt(); 8:4`q9  
nStartPos = new long[nCount]; h_ J|uu  
nEndPos = new long[nCount]; aFwfF^\(|,  
for(int i=0;i<nStartPos.length;i++) fO$~jxR.  
{ cLCzLNyKl  
nStartPos = input.readLong(); *saO~.-;4  
nEndPos = input.readLong(); [bJAh ` I  
} {t&+abY
 
input.close(); p&,2@(Q  
} kR|(hA,$N  
catch(IOException e){e.printStackTrace ();} z}*74lhF  
catch(Exception e){e.printStackTrace ();} SZ"^>}zl=  
} Q5qQ%cu  
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private void processErrorCode(int nErrorCode) XW9 [VUW~  
{ OX/}j_8E^(  
System.err.println("Error Code : " + nErrorCode); U2VnACCUZs  
} ^LJ
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j 1#T]CDs  
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//停止文件下载 L[9]Ez$2+  
public void siteStop() s7TV@Y)  
{ JIyIQg'5i  
bStop = true; LuIs4&
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for(int i=0;i<nStartPos.length;i++) \m;"KyP+  
fileSplitterFetch.splitterStop(); xT1{O`  
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} 4>xv7  
} #3act)m  
//负责部分文件的抓取 -QUvd1S40  
**FileSplitterFetch.java [XP3  
*/ _w>9Z>PR  
package NetFox; cYMlcwS  
:N([s(}!$2  
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import java.io.*; Bn_@R`  
import java.net.*; _jCjq   
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public class FileSplitterFetch extends Thread { Dx<CO1%z-  
:X;AmLf`2u  
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String sURL; //File URL sd~T  
long nStartPos; //File Snippet Start Position RW. >;|m  
long nEndPos; //File Snippet End Position 
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int nThreadID; //Thread's ID oZ(T`5  
boolean bDownOver = false; //Downing is over {|J'd+  
boolean bStop = false; //Stop identical ?krgZ;Jj  
FileAccessI fileAccessI = null; //File Access interface I*^3 Z  
+e%U6&l{  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException .5x+FHu7  
{ /N&)r wc  
this.sURL = sURL; c0%%X!!$  
this.nStartPos = nStart; W!BIz&SY:-  
this.nEndPos = nEnd; &% \`Lwh  
nThreadID = id; ^.9I[Umua  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ard<T}|N  
} \kGi5G]  
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public void run() 4W''j[Y/  
{ ,,>b=r_r&  
while(nStartPos < nEndPos && !bStop) *.DTcV  
{ G:2m)0bW  
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try{ EO5k?k[*  
URL url = new URL(sURL); d?/?VooU  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Vuqm{bo^  
httpConnection.setRequestProperty("User-Agent","NetFox"); /WJ*ro]Hd$  
String sProperty = "bytes="+nStartPos+"-"; B^SD5  
httpConnection.setRequestProperty("RANGE",sProperty); V3u[{^^f  
Utility.log(sProperty); 6DG:imGl  
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InputStream input = httpConnection.getInputStream(); ;ip"V 0`  
//logResponseHead(httpConnection); a!>yX ex  
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byte[] b = new byte[1024]; tzhkdG  
int nRead; TKsze]/q  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Uaho.(_GP  
{ ='0f#>0Q  
nStartPos += fileAccessI.write(b,0,nRead); #~r+  
//if(nThreadID == 1) jyt#C7mj-A  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); )k8=< =s  
} *$Df)iI6  
*kXSl73 k  
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Utility.log("Thread " + nThreadID + " is over!"); c2z%|\q  
bDownOver = true; 'V5^D<1P  
//nPos = fileAccessI.write (b,0,nRead); MhNDf[W>  
} =x4:jas  
catch(Exception e){e.printStackTrace ();} bV#U&)|  
} PL#
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} \1[I(u  
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//打印回应的头信息 (c<Krc h  
public void logResponseHead(HttpURLConnection con) 2@ >04]
 
{ T7AFL=  
for(int i=1;;i++) /]Fs3uf  
{ *@q+A1P7@  
String header=con.getHeaderFieldKey(i); QM1-w^  
if(header!=null) |yi3y `f  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); \:8eN}B  
Utility.log(header+" : "+con.getHeaderField(header)); 9K@>{69WQ  
else FBM 73D@`  
break; T{={uzQeJJ  
} u":D{+wC|  
} ^IxT.g  
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,*2%6t`N?  
public void splitterStop() UlHRA[SCv  
{ zv]-(<B  
bStop = true; iAX\F`  
} j w)Lofn  
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} pC
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/* ,#1ke  
**FileAccess.java WYQJ+z5  
*//文件访问(定位，写) J<Wz3}w6  
package NetFox; aXyu%<@k  
import java.io.*; EOrWax@k$}  
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public class FileAccessI implements Serializable{ "-y\F}TE  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 N5rY*S  
RandomAccessFile oSavedFile; cWl)ZE<hM  
long nPos; (XJehdB0  
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public FileAccessI() throws IOException Bo?uwi  
{ CJ_X:Frj)  
this("",0); ~4[2{M.0>@  
} v.)'be*u  
~ X8U@f  
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public FileAccessI(String sName,long nPos) throws IOException i+yqsYKO  
{ :b;2
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oSavedFile = new RandomAccessFile(sName,"rw"); 13.v5v,l  
this.nPos = nPos; WIXzxI<)  
oSavedFile.seek(nPos); y6'Fi(2yw  
} H*3f8A&@s  
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public synchronized int write(byte[] b,int nStart,int nLen) {nT !|S)$  
{ %5*gsgeI  
int n = -1; ](NSpU|*  
try{ :tM|$TZ  
oSavedFile.write(b,nStart,nLen); .s|n}{D_i  
n = nLen; Z~8Xp  
} _> .TB\  
catch(IOException e) |v8>22y  
{ 9u1)Kr=e  
e.printStackTrace (); )_b#c+  
} 4x=rew>Ew  

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return n; *}3e'0`  
} jK\2y|&&c  
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} ;C-5R U V  
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!,Wd$UK  
/* 7|T<dfQk  
**SiteInfoBean.java %96JH YcX  
*/ je.jui"  
package NetFox; (`4^|_gw  
-:m;ePK  
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public class SiteInfoBean { +H_Jr'/  
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private String sSiteURL; //Site's URL kj
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private String sFilePath; //Saved File's Path
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private String sFileName; //Saved File's Name q^Lj)zmnK  
private int nSplitter; //Count of Splited Downloading File ^o"9f1s5  
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public SiteInfoBean() a9"x_IVU  
{//nSplitter的缺省值为5 OnF+  
//default value of nSplitter is 5 ('W#r"  
this("","","",5); KU3lAjzN  
} RX>kOp29  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) IoJkM-^H&)  
{ X.xp
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sSiteURL= sURL; W<yh{u&,  
sFilePath = sPath; x 3#1  
sFileName = sName; KwWqsuju  
this.nSplitter = nSpiltter; W+a>*#*  
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} )qD%5} t  
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public String getSSiteURL() jN 5Hku[?  
{ tHXt*tzq  
return sSiteURL; 
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} Vfp{7I$#6"  
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public void setSSiteURL(String value)  nq8mzI  
{ ]ss0~2  
sSiteURL = value; ;:cU/{W  
} oj$D3  
/`D]m?  
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public String getSFilePath() KI-E=<zt  
{ z>vz
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return sFilePath; Ws4aCH1  
} W )q^@6[d  
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public void setSFilePath(String value) bL!NT}y`  
{ #; E,>0  
sFilePath = value;
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} -&M9Yg|Se  
nmc=RK^cM  
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public String getSFileName() G#)>D$Ck#  
{ 4Me*QYD  
return sFileName; 5IBe;o  
} E0>4Q\n{  
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T
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public void setSFileName(String value) 5ts8o&|   
{ =!9+f  
sFileName = value; pJVzT,poh  
} :"3WC
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public int getNSplitter() n+rAbn5o$  
{ g*
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return nSplitter; T5-50nU,~  
} C z4"[C`;  
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public void setNSplitter(int nCount) PsEm(.z  
{ !0fpD'f!n  
nSplitter = nCount; cA`R~o"  
} R5r )01  
} 6WgGewn  
jkFS=eonK  
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/* `{N0+n  
**Utility.java #|GP]`YT  
*/ z~A||@4'  
package NetFox; <!Nj2>  
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public class Utility { E3_e~yu&  
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public Utility() e8a_)TU?  
{ xFHc+m' m~  
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} v~?d7p{  
z\oq b)a  
//线程睡眠 "7JO~T+v  
public static void sleep(int nSecond) %^p1ax  
{ &tj0Z:  
try{ n9050&_S  
Thread.sleep(nSecond); ?<#6=  
} rfkk3oy  
catch(Exception e) dum! AO  
{ {Lk~O)E  
e.printStackTrace (); ,6}HAC $  
} 9-Ikd>9  
} 0J7[n*~  
.2C}8GGC'  
//日志 Fm`hFBKW  
public static void log(String sMsg) +%7yJmMw  
{ pOyM/L   
System.err.println(sMsg); *,%H1)Tj}  
} 7F>5<Gv:-  
DFwkd/3"  
F8Rd#^9PD  
public static void log(int sMsg) 
)V!9&  
{ X'TQtI  
System.err.println(sMsg); 14]!LgH  
} YS{])+s  
} r'7;:  
q^JJ5{36e  
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/* n (C*LK  
**TestMethod.java GLcf'$l  
*/ d?oupW}uu  
package NetFox; 0 oEw1!cY  
y/$WjFj3"  
!qV{OXdrB
 
public class TestMethod { gLsl/G  
zg.'  
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public TestMethod() oA(jtX[(  
{ ///xx/weblogic60b2_win.exe ^e"BY(  
try{ 0<>I\UN0b  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); T@U_;v|rf  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); E=Ah_zKU  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ?uc=(J+6  
fileFetch.start(); hvtg_w6K  
} 6|V713\  
catch(Exception e){e.printStackTrace ();} <?yAIhgN*  
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} L Bb&av  
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public static void main(String[] args) mEa\0oPGB  
{ k_r12Bu  
new TestMethod(); pD9*WKEf*  
} yc8iT`
 
} SuB;Nb7r`  
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