http断点续传简单实现（java)

/* uSR~@Lj ~  
**SiteFileFetch.java nM0[P6p  
*/ Zw~
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package NetFox; 59Gk3frk(  
import java.io.*; $]q8, N|1  
import java.net.*; 2^^=iU=!<|  
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public class SiteFileFetch extends Thread { Y!T %cTK)a  
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SiteInfoBean siteInfoBean = null; //文件信息Bean "kA*Vc#  
long[] nStartPos; //开始位置 eBJUv]o %  
long[] nEndPos; //结束位置 Q8_ d)t|  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 @GvztVYo  
long nFileLength; //文件长度 HdLH2+|P;D  
boolean bFirst = true; //是否第一次取文件 CQpC
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boolean bStop = false; //停止标志 =?-ye!w  
File tmpFile; //文件下载的临时信息 =Z+nX0qF  
DataOutputStream output; //输出到文件的输出流 Tt>8?  
}E7:ihy  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） k}#;Uy=5  
public SiteFileFetch(SiteInfoBean bean) throws IOException Tdc3_<1  
{ 1=]kWp`i  
siteInfoBean = bean; yu;SH[{Wi  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); `~W-Xx  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); g38&P3/
 
if(tmpFile.exists ()) Kb^>-[Yx  
{ Y1arX^Zb  
bFirst = false; "rAY.E]  
read_nPos(); NzW`B^p  
} :F?x)"WoQ+  
else 8+Bu+|c%f  
{ aceZ3U>W  
nStartPos = new long[bean.getNSplitter()]; *;XWLd#  
nEndPos = new long[bean.getNSplitter()]; wlPx,UqZ  
} 2+Wzf)tB  
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} U #~;)fZ  
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public void run() P%MfCpyj  
{ v{<[)cr  
//获得文件长度 P6Mhbmt9*  
//分割文件 zW8*EE+,  
//实例FileSplitterFetch [0UGuj
  
//启动FileSplitterFetch线程 K]xa/G(  
//等待子线程返回 wIf {6z{  
try{ |0z;K:5s
 
if(bFirst) hwqbi "o  
{ Y+qQIMZ  
nFileLength = getFileSize(); dz[ bm<T7  
if(nFileLength == -1) m~'? /!!  
{ ! <WBCclX  
System.err.println("File Length is not known!"); fKtV'/X;Q  
} HWm#t./  
else if(nFileLength == -2) 3u33a"nL8  
{ j(#%tIv  
System.err.println("File is not access!"); %5\3Aw  
} *XWq?hi  
else -]:GL>b  
{ fj,m  
for(int i=0;i<nStartPos.length;i++) Q# ?wXX47  
{ [
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); 
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} ]8;n{ }X  
for(int i=0;i<nEndPos.length-1;i++) yA[({2%  
{ Pj?Dmk~   
nEndPos = nStartPos[i+1]; CCDDK L]N:  
} !SsHAE|  
nEndPos[nEndPos.length-1] = nFileLength; !q"CV  
} &2I*0  
} ,LOQDIyn  
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//启动子线程 F&;   
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; VzlDHpG  
for(int i=0;i<nStartPos.length;i++) 6*@yE  
{ W0cgI9=9  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), insY(.N  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), o0z67(N&g  
nStartPos,nEndPos,i); "'Z- UV  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); YH:8<O,{-  
fileSplitterFetch.start(); cyd~2\Kv~  
} SJgY  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), l|/:Ot  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); iz"3\{aN  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 3,aN8F1;C  
nEndPos = " + nFileLength); f0Hq8qAF;^  
// fileSplitterFetch[nPos.length-1].start(); 5c-N0@\  
o!&WsD  
V7t!?xOL  
//等待子线程结束 bb=uF1  
//int count = 0; @=uN\) 1  
//是否结束while循环 B>TSdn={>  
boolean breakWhile = false; o`r(`6@  
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while(!bStop) 8}BBOD  
{ .gYt0raSY  
write_nPos(); ~S(^T9R  
Utility.sleep(500); S-Ai3)t6  
breakWhile = true; 5^)_B;.f  
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for(int i=0;i<nStartPos.length;i++) i</J@0}y  
{ ;6DnId2Zh  
if(!fileSplitterFetch.bDownOver) Rs$5PdH  
{ 7!2 HNg  
breakWhile = false; CB*/ =Y  
break; RazBc.o<  
} Q;26V4  
} d\]O'U)s  
if(breakWhile) u3dsQU  
break; QB1M3b  
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//count++; Jyu`-=It  
//if(count>4) lfS;?~W0k  
// siteStop(); |Cf mcz(56  
} Fh`-(,e?5  
#/WAzYt{  

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System.err.println("文件下载结束！"); elbG\qXBp  
} vR]mSX3)?  
catch(Exception e){e.printStackTrace ();} |NEd@  
} iVeQ]k(u  
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//获得文件长度 sb'p-Mj  
public long getFileSize() R`Qpd3  
{ G?[-cNdk  
int nFileLength = -1; ]p$zvMf}  
try{ UB&2f>  
URL url = new URL(siteInfoBean.getSSiteURL()); @+dHF0aXd  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Ed=}PrE  
httpConnection.setRequestProperty("User-Agent","NetFox"); eU~?p|Np
 
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 ^Fp=y
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int responseCode=httpConnection.getResponseCode(); BkT-m'I?  
if(responseCode>=400) E$T(Qu<-  
{ ji##$xC  
processErrorCode(responseCode); ]BfR.,,  
return -2; //-2 represent access is error %Qd3BZ  
} 2[BA(B  
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String sHeader; HPTHF  
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for(int i=1;;i++) 1t%<5O;R  
{ +{Gw9h"5g*  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); <O bHf`Q  
//Utility.log(in.readLine()); um}N%5GAa  
sHeader=httpConnection.getHeaderFieldKey(i); QqjTLuN  
if(sHeader!=null) <THUsY`3P&  
{ voH4  
if(sHeader.equals("Content-Length")) s+N^PX3  
{ cb4b,Ri  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); $~TfL{$  
break; FSVS4mtiX\  
} 2| $k`I,  
} QglYU  
else F*X%N_n  
break; w0$R`MOR+  
} 9kUV1?  
} Z3Gm  
catch(IOException e){e.printStackTrace ();} *<?XTs<  
catch(Exception e){e.printStackTrace ();} &E`9>&~J  
< )Alb\Z  
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Utility.log(nFileLength); A mvw`u>  
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return nFileLength; phe"JNML  
} yIlV[_  
E+:.IuXW$  
!>q?dhw@  
//保存下载信息（文件指针位置） ,v|CombIc.  
private void write_nPos() }]tFz}E\  
{ jjYM3LQcdP  
try{ kz$(V(k<  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Euqjxz  
output.writeInt(nStartPos.length); VVgsLQd  
for(int i=0;i<nStartPos.length;i++) Q;=6ag'  
{ |x*{fXdMhr  
// output.writeLong(nPos); vP-3j  
output.writeLong(fileSplitterFetch.nStartPos); 3.B4(9:>,  
output.writeLong(fileSplitterFetch.nEndPos); r+SEw ;  
} a4L
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output.close(); umqLKf=x!  
} G]1(X38[si  
catch(IOException e){e.printStackTrace ();} IPwj_jvw  
catch(Exception e){e.printStackTrace ();} ^}>zYt  
} ;5-R=e(KA  
+}kO;\  
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//读取保存的下载信息（文件指针位置） c6f|y_2  
private void read_nPos() mu 2 A%"7  
{ <'yf|N
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try{ $+A%ODv  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); qPL^zM+  
int nCount = input.readInt(); |if~i;VKL  
nStartPos = new long[nCount]; dK[*
 
nEndPos = new long[nCount]; PbbXi  
for(int i=0;i<nStartPos.length;i++) lb-S0plw  
{ ,}eRnl
\  
nStartPos = input.readLong(); @47[vhE  
nEndPos = input.readLong(); 14mXx}O  
} j2< !z;2  
input.close(); ^fFtI?.6jI  
} hO5K
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catch(IOException e){e.printStackTrace ();} Vf"O/o}hq,  
catch(Exception e){e.printStackTrace ();} Uzan7A  
} IOSuaLH^  
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private void processErrorCode(int nErrorCode) %'RI3gy  
{ PN1(j|  
System.err.println("Error Code : " + nErrorCode); Wv6z%r<  
} pe\Txg
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MV Hz$hy
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//停止文件下载 k7:GS
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public void siteStop() 3I'M6WA  
{ 34X(J-1\|i  
bStop = true; %E4$ZPSW  
for(int i=0;i<nStartPos.length;i++) ?l)}
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fileSplitterFetch.splitterStop(); @4G.(zW  
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} ?&whE!  
} )![f\!'PI  
//负责部分文件的抓取 ^2&O3s
  
**FileSplitterFetch.java g\ 8#:@at  
*/ Q\&AlV  
package NetFox;
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3EbnZb  
import java.io.*; sDzD 8as  
import java.net.*; .fio<mqi  
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public class FileSplitterFetch extends Thread { \j,v/C@c-  
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String sURL; //File URL q3,P|&T  
long nStartPos; //File Snippet Start Position <6d{k[7fz)  
long nEndPos; //File Snippet End Position (5f5P84x  
int nThreadID; //Thread's ID USnD7I/b  
boolean bDownOver = false; //Downing is over *3w/`R<\  
boolean bStop = false; //Stop identical .LeF|EQU\@  
FileAccessI fileAccessI = null; //File Access interface "6`)vgI~  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException gTmUK{y'  
{ !#@4xeBPo  
this.sURL = sURL; Vz7w{HY  
this.nStartPos = nStart; \,@Yl.,+  
this.nEndPos = nEnd; 9sfB+]}h  
nThreadID = id; [T}%q"<  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 +eV4g2w)  
} .J<qfQ  
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public void run() *uI hxMX  
{ NE;(..  
while(nStartPos < nEndPos && !bStop) ReHd~G9  
{ ^H\-3/si*  
}<}`Q^Mlk  
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try{ 8Y{}p[UFT  
URL url = new URL(sURL); Y1Gg (z  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 0w'y#U)&8  
httpConnection.setRequestProperty("User-Agent","NetFox"); V~]'+A q>  
String sProperty = "bytes="+nStartPos+"-"; xnhDW7m  
httpConnection.setRequestProperty("RANGE",sProperty); J1c&"Oh  
Utility.log(sProperty); RV#uy]  
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InputStream input = httpConnection.getInputStream(); 9(N)MT5F  
//logResponseHead(httpConnection); A&}nRP9  
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O=#/DM;  
byte[] b = new byte[1024]; :m)Rmwn_  
int nRead; ^qId]s  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) yqVaA 'w5  
{ k`2B9,z  
nStartPos += fileAccessI.write(b,0,nRead); Mc$v~|i6  
//if(nThreadID == 1) lU50.7<08  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); %)6:eIS  
} ,# jOf{L*  
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2=/g~rp*  
Utility.log("Thread " + nThreadID + " is over!"); a`@<ZsR  
bDownOver = true;
#/B~G.+(  
//nPos = fileAccessI.write (b,0,nRead); 'De'(I  
} ,QHx*~9  
catch(Exception e){e.printStackTrace ();} )q]j?Z.  
} C_^R_  
}
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//打印回应的头信息 $Pb[c%'  
public void logResponseHead(HttpURLConnection con) ^K77V$v  
{ 1O3<%T#LOZ  
for(int i=1;;i++) 1TxhEXB  
{ I|3v&E1  
String header=con.getHeaderFieldKey(i); C#?d
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if(header!=null) sm&rR=b  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); :J4C'N  
Utility.log(header+" : "+con.getHeaderField(header)); %wjU^Urya  
else LN6JH!  
break; LWb}) #E  
} fN*4(yw  
} jf)JPa_  
;,B@84'  
= cI\OsV&?  
public void splitterStop() ;k41+O:f@  
{ {8bY7NH|  
bStop = true; HG3>RcB  
} DwrCysIK  
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} /h.3<HI."*  
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/* }9Dv\"
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**FileAccess.java xo_k"'f+  
*//文件访问(定位，写) &$z1
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package NetFox; dv9Pb5i  
import java.io.*; w>q_8V_K  
+VW]
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public class FileAccessI implements Serializable{ .Zt/e>K&  
 iIEIGQx  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 QEHZ=Yg%3  
RandomAccessFile oSavedFile; r|F,\fF  
long nPos; 8}0y)aJ  
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public FileAccessI() throws IOException HY|SLk/E  
{ .&Gtw _  
this("",0); L8K3&[l%  
} n2hsG.4  
]{U*+K%,J  
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public FileAccessI(String sName,long nPos) throws IOException VM|)\?Q  
{ cWy0N  
oSavedFile = new RandomAccessFile(sName,"rw"); Cv7RCjMw  
this.nPos = nPos; %t
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oSavedFile.seek(nPos); C)^\?DH  
} W",jZ"7  
p;Ok.cXVp  
2}\sj'0&  
public synchronized int write(byte[] b,int nStart,int nLen) J;Xz'0
 
{ \mit&EUh}  
int n = -1; um;U;%?Q  
try{ ?gP/XjToMg  
oSavedFile.write(b,nStart,nLen); EMH}VigR  
n = nLen; Jpnp'  
} 2qR@:^  
catch(IOException e) UiN ^x  
{ .shI%'V  
e.printStackTrace (); n,%^R  
} dM.Ow!j  
>'g60R[  
^w}Ib']X  
return n; S?WUSx*N  
} o%Q'<0d  
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} l%w|f`B:  
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/* 2a}_|#*  
**SiteInfoBean.java 9uo\&,,  
*/ V:
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package NetFox; ../(gG9  
!LESRh?  
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public class SiteInfoBean { N#qoKY(#  
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private String sSiteURL; //Site's URL ,peFNpi  
private String sFilePath; //Saved File's Path MQI=  
private String sFileName; //Saved File's Name p[I
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private int nSplitter; //Count of Splited Downloading File \Bf{/r5x  
N* QI>kzU  
L>*|T[~  
public SiteInfoBean() }:Akpm
 
{//nSplitter的缺省值为5 HKf3eC  
//default value of nSplitter is 5 {K}+$jzGVt  
this("","","",5); }\*|b@)]  
} FL}8h/  
83|/sWrvh  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ~Y$1OA8  
{ l$NEx0Dffz  
sSiteURL= sURL; dv:
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sFilePath = sPath; @B <_h+  
sFileName = sName; 8;@eY`0(  
this.nSplitter = nSpiltter; PI?[  
r>OE[C69  
uhLW/?q.  
} :2+:(^l  
O\z%6:'M  
/vU31_eZt  
public String getSSiteURL() }r[BME  
{ UHwrssX&3  
return sSiteURL; 3Hr%G4  
} qxNV~aK  
x3 <Lx^;  
xae
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public void setSSiteURL(String value) bL<cgtz7)  
{ yCVBG  
sSiteURL = value; ]cK@
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} Sr0mA M  
z%z$'m  
x4(WvQ%O#  
public String getSFilePath() /nNHI34  
{ )ALcmC?!#  
return sFilePath; p_( NLJ%  
} W&nVVV8s@  
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%vI]"a@  
public void setSFilePath(String value) c s>W6  
{ x :s-\>RcA  
sFilePath = value; 78kk"9h'  
} 4?cg6WJ'6  
0&)4^->c  
.#SWfAb2h  
public String getSFileName() u=5^xpI<D
 
{ G!uxpZ   
return sFileName; BC3I{Y|  
} <_}u5E)7(  
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public void setSFileName(String value) qohUxtnTK>  
{ xE:p)B-]  
sFileName = value; *Zln\Sx  
} W/+0gh7`,(  
o{/D:B  
L))
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public int getNSplitter() L3S,*LnA  
{ 7_LE2jpC,5  
return nSplitter; I#0$5a},u^  
} oVs&r?\Z  
*l}q,9iQ-  
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public void setNSplitter(int nCount) q;U[
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{ ?%?@?W>s@  
nSplitter = nCount; ;G?_^ 0  
} K.k=\N  
} #u>JCPz  
JA&w"2X*E  
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/* :`d& |BB  
**Utility.java $?7}4u,  
*/ ,JR7N_"I  
package NetFox; UGIyNMY  

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r__uPyIMG/  
public class Utility { {min9  
3.Y/ZWON  
3]T2Zp&;  
public Utility() y5>H>NS  
{ `.@N9+Aj  
N[Fz6,ZG _  
SNcaIzbr  
} HyB!
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`6'fX[j5  
//线程睡眠  'y1=Z  
public static void sleep(int nSecond) [H!V  
{ ) "'J]6  
try{ !-[e$?-  
Thread.sleep(nSecond); XvWUJ6M  
} qWdL|8  
catch(Exception e) wTG6>l]H  
{ kd2+k4@#  
e.printStackTrace (); v#F
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} (Zp'|hx8o  
} cl[rgj  
? 3T
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//日志 =98@MX%P  
public static void log(String sMsg) #Fq6-]y1")  
{ !CUrpr/*  
System.err.println(sMsg); THC34u]  
} n1X7T0'  
}}@xx&  
y\]:&)?&C^  
public static void log(int sMsg) Bg{"{poy  
{ |4UW.dGHPo  
System.err.println(sMsg);
:T.j;~  
} M, f6UYo=  
} 4vC { G.  
Qt`}$]
 
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/* O8qA2@,  
**TestMethod.java yP.,Dh s  
*/ Jsde+G,N  
package NetFox; ye4 T2=  
K 0R<a~  
i|2CZ  
public class TestMethod { 5o-WA1  
ZjLuqo  
  
public TestMethod() L;6L@D6  
{ ///xx/weblogic60b2_win.exe Xy0*1$IS]  
try{ 9\y\{DHd  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); :@K1pAh4  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ;hzm&My  
SiteFileFetch fileFetch = new SiteFileFetch(bean); @'P\c   
fileFetch.start(); v"-@'qN'  
} vuN!7*d+  
catch(Exception e){e.printStackTrace ();} Ls51U7  
?o$ hlX  
,%Sf,h?"^  
} _=$:<wIE[  
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public static void main(String[] args) `?P)RS30  
{ nz
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new TestMethod(); O S?S$y  
} 4+?d0  
} Ct@OS227x  
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