http断点续传简单实现（java)

/* W} +6L|  
**SiteFileFetch.java ywa.cq  
*/ mm9S#Ya  
package NetFox;  cB{;Nh6"  
import java.io.*; o@V/37!  
import java.net.*; B2+_F"<;  
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public class SiteFileFetch extends Thread { fqp7a1qQl  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ]H@
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long[] nStartPos; //开始位置 (Gb{ckzs  
long[] nEndPos; //结束位置 XajY'+DIsz  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Jv$2wH  
long nFileLength; //文件长度 Sv]"Y/N  
boolean bFirst = true; //是否第一次取文件 Z(clw  
boolean bStop = false; //停止标志 W SeRV?+T  
File tmpFile; //文件下载的临时信息 cH8H)55F  
DataOutputStream output; //输出到文件的输出流 0eu$oel-  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） -wHGi  
public SiteFileFetch(SiteInfoBean bean) throws IOException t"@|;uPAu  
{ uZ{xt6 f  
siteInfoBean = bean; @RG3*3(  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 9~ .BH;ku  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Ra,on&OP`*  
if(tmpFile.exists ()) O8}s*}]  
{ U";Rp&\3;  
bFirst = false; }lbx  
read_nPos(); &[\arwe)  
} N pIlQaMo4  
else Fu
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{ i3\oy`GJ  
nStartPos = new long[bean.getNSplitter()]; G}O
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nEndPos = new long[bean.getNSplitter()]; 6/
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} er}'}n`@q  
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} 4w  
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public void run() YH6K-}  
{ m3ZOq B-  
//获得文件长度 Z|7I }i  
//分割文件 f#JF5>o  
//实例FileSplitterFetch !{-
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//启动FileSplitterFetch线程 x-P_}}K 79  
//等待子线程返回 ~1z8G>R  
try{ NxRiEe#m  
if(bFirst) 1JY90l$ME  
{ !Kn+*'#  
nFileLength = getFileSize(); cF6@.)  
if(nFileLength == -1) (>% Vj  
{ )FiU1E  
System.err.println("File Length is not known!"); .Sth  
} %JU23c*  
else if(nFileLength == -2) a*@Z^5f  
{ 60gn`s,,  
System.err.println("File is not access!"); mTu9'/$(  
} 5 BG&r*U  
else "alO"x8t  
{ JQv ZTwSI  
for(int i=0;i<nStartPos.length;i++) Xrs~ove1V  
{ #nL0Hx7]E  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); YmF(o  
} 2QD B'xs3  
for(int i=0;i<nEndPos.length-1;i++) T</gWW  
{ cnO4NUDv  
nEndPos = nStartPos[i+1]; HCZ%DBU96  
} :)S4MoG  
nEndPos[nEndPos.length-1] = nFileLength; z^a?t<+  
} r]vBr^kq  
}  Z~:lfCK`  
lP &%5y;  
Hw3ES  
//启动子线程 Kct +QO(  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; d:ajD  
for(int i=0;i<nStartPos.length;i++) uy28=BE  
{ t$Ji{t-  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Z%d4V<fn  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ^E,UcK;  
nStartPos,nEndPos,i); aj~@r3E;  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); {?_)m/
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fileSplitterFetch.start(); S`-IQ,*}  
} 0To 5|r  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), u+I3VK_)  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); T"lqPbK  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", rW .0_*  
nEndPos = " + nFileLength); Ft>8 YYyU  
// fileSplitterFetch[nPos.length-1].start(); l"g%vS,;`  
"TCbO`mg  
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//等待子线程结束 KAaeaiD  
//int count = 0; `qEm5+`  
//是否结束while循环 DEuW'.o>  
boolean breakWhile = false; m$j;FKz+|  
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while(!bStop) ?=Qg  
{ clV/i&]Qa  
write_nPos(); TW? MS em  
Utility.sleep(500); )W3l{T(  
breakWhile = true; a];i4lt(c  
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for(int i=0;i<nStartPos.length;i++) 5Wjp_^!e  
{ `2+52q<FO  
if(!fileSplitterFetch.bDownOver) (S{c*"}2  
{ W u{nC  
breakWhile = false; .;Yei6H  
break; AE~}^(G`  
} <T9m.:l  
} G7xjW6^T  
if(breakWhile) 7]53GGNO  
break; eeZ9 w~<  
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//count++; uQ)]g  
//if(count>4) jl7-"V>j?;  
// siteStop(); |]^! 4[!U  
} \}c50}#0  
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System.err.println("文件下载结束！"); -I<`!kH*  
} o?\Pw9Y  
catch(Exception e){e.printStackTrace ();} l^Z~^.{y  
} $RO=r90o  
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//获得文件长度 < ,n4|z)  
public long getFileSize() WVFy ZpB  
{ }7^*%$  
int nFileLength = -1; jR:Fih-}  
try{ (CwaOm{g  
URL url = new URL(siteInfoBean.getSSiteURL()); an@Ue7  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 4\iQ%fb  
httpConnection.setRequestProperty("User-Agent","NetFox"); ;bmd<1  
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int responseCode=httpConnection.getResponseCode(); s)=7tHoqB)  
if(responseCode>=400) ^4i3#}  
{ 4Yk(ldR~  
processErrorCode(responseCode); OC.@C}u  
return -2; //-2 represent access is error M1\/ueOe  
} cQb%bmBc5  
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String sHeader; T9yW# .  
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for(int i=1;;i++) |&.)_+w  
{ 4T-AWk  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); B(U`Zd  
//Utility.log(in.readLine()); /vKDlCH*  
sHeader=httpConnection.getHeaderFieldKey(i); sIe(;%[`  
if(sHeader!=null) U^I'X7`r  
{ fx5vaM!  
if(sHeader.equals("Content-Length")) pj`-T"Q  
{ pDT6>2t  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); |\ L2q/u  
break; j=LF1d
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} )i>KgX  
} BGS6uV4^>  
else ~b/>TKn+  
break; mB`r6'#=  
} &,xM;8b  
} 7v_e"[s~  
catch(IOException e){e.printStackTrace ();} Zl*!pQ  
catch(Exception e){e.printStackTrace ();} 1-fz5
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Utility.log(nFileLength); Bc@e;k@i  
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return nFileLength; 3& $E  
} J(]nPwm=.-  
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//保存下载信息（文件指针位置） cE[
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private void write_nPos() 6=
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{ OWzIea@  
try{ %K4-V5f  
output = new DataOutputStream(new FileOutputStream(tmpFile)); iD~s,  
output.writeInt(nStartPos.length); hb{(r@[WHv  
for(int i=0;i<nStartPos.length;i++) bB["Qd}
Q  
{ |9h[Q[m  
// output.writeLong(nPos); "Y+`U  
output.writeLong(fileSplitterFetch.nStartPos); ([|M,P6e)U  
output.writeLong(fileSplitterFetch.nEndPos); qJsEKuOs  
} ,??|R`S  
output.close(); p%_TbH3j`  
} AKVmUS;70  
catch(IOException e){e.printStackTrace ();} SF7Kb`>Y  
catch(Exception e){e.printStackTrace ();} Q\Eq(2p  
} @{G(.S  
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//读取保存的下载信息（文件指针位置） e;$
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private void read_nPos() %F7k| Na  
{
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try{ IM+PjYJ  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); R!=XMV3$PH  
int nCount = input.readInt(); >8##~ZuF+
 
nStartPos = new long[nCount]; v3B ^d}+.  
nEndPos = new long[nCount]; h?b{{  
for(int i=0;i<nStartPos.length;i++) \[BnAgsF  
{ E4Sp^,  
nStartPos = input.readLong(); AMr9rBd  
nEndPos = input.readLong(); Fpb1.Iz  
} Gu-Sv!4p  
input.close(); *,(`%b[  
} NNT9\JRv_  
catch(IOException e){e.printStackTrace ();} C^a~)r.h  
catch(Exception e){e.printStackTrace ();} MB)xL-jO  
} 2WoB;=  
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private void processErrorCode(int nErrorCode) \Z$*8z=  
{ n~h%K7 c  
System.err.println("Error Code : " + nErrorCode); @AwH?7(b  
} |7argk+  
j'W)Nyw$[  
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//停止文件下载 :JlJB  
public void siteStop() eNNK;xXe#  
{ zK&`&("4C  
bStop = true; Je/R'QP^8  
for(int i=0;i<nStartPos.length;i++) Y<B| e91C  
fileSplitterFetch.splitterStop(); ^l9S5 {  
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} ?^hC|IR$  
} ;tHF$1!J  
//负责部分文件的抓取 tP\Utl-0  
**FileSplitterFetch.java 5o,82Kti  
*/ B
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package NetFox; gP}M\3-O  
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import java.io.*; FY'f{gD^  
import java.net.*; 7}Gy%SJ`  
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public class FileSplitterFetch extends Thread { yk=H@`~!  
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String sURL; //File URL qU"+0t4  
long nStartPos; //File Snippet Start Position d-Sm<XHu.  
long nEndPos; //File Snippet End Position j
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int nThreadID; //Thread's ID js{ RaR=  
boolean bDownOver = false; //Downing is over ]!/1qF  
boolean bStop = false; //Stop identical (qaY,>je]D  
FileAccessI fileAccessI = null; //File Access interface wm}i+ApK  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException <_D+'[  
{ j,~h:MT  
this.sURL = sURL; %l>^q`p  
this.nStartPos = nStart; D~-
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this.nEndPos = nEnd; P63f0F-G  
nThreadID = id; O@l`D`  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 *_ "j"{  
} pvX\kX3}  
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public void run() :5ji.g* 0  
{ r!;NH3 *  
while(nStartPos < nEndPos && !bStop) !a  /  
{ O:1YG$uKa  
/V,:gLpQ  
8 }-"&-X  
try{ WKN\*N<  
URL url = new URL(sURL); hp)3@&T  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 8^O|Aa$IF:  
httpConnection.setRequestProperty("User-Agent","NetFox"); 4YKb~1qkk  
String sProperty = "bytes="+nStartPos+"-"; YYhRdU/g  
httpConnection.setRequestProperty("RANGE",sProperty); GSypdEBj+w  
Utility.log(sProperty); $Q62 7  
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InputStream input = httpConnection.getInputStream(); nH;^$b'LZ  
//logResponseHead(httpConnection); `S%pD.g,2  
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byte[] b = new byte[1024]; myH#.$=A  
int nRead; !.9NJ2'8  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) L='GsjF0}  
{ KX{S8_  
nStartPos += fileAccessI.write(b,0,nRead); 8}4V
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//if(nThreadID == 1) &QvWT+]c'0  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ^!=+$@<  
} 4PNl3N3,n  
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Utility.log("Thread " + nThreadID + " is over!"); ibEQ52  
bDownOver = true; q")}vN  
//nPos = fileAccessI.write (b,0,nRead); }E*#VA0/nY  
} wL~ dZ!,J  
catch(Exception e){e.printStackTrace ();} GQq2;%RrF  
} lE /"  
} JPmW0wM  
h T4fKc7P  
u"nyx0<  
//打印回应的头信息 tlc&Wx  
public void logResponseHead(HttpURLConnection con) !tN]OQ)'  
{ |XPT2eQ{  
for(int i=1;;i++)  QH;1*  
{ ;|66AIwDe  
String header=con.getHeaderFieldKey(i); 68d(6?OgW  
if(header!=null) \!`*F:7]-  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); `*N2x\+X  
Utility.log(header+" : "+con.getHeaderField(header)); lr=*Ty(V  
else Z>'.+OW  
break; wuI+$?  
} e:&5Cvx  
} {=pf#E=  
{~VgXkjsC  
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public void splitterStop() +tl&Jjd
m  
{ }]kzj0m  
bStop = true; {l![{  
} H>k=V<  
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} 4?;1cXXA  
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/* d.sxB}_O  
**FileAccess.java C}%g(YRhb  
*//文件访问(定位，写)  ^~?VD  
package NetFox; v:eVK!O  
import java.io.*; B]#0]-ua  
cW%F%:b  

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public class FileAccessI implements Serializable{ MYDAS-  
M
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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 ]=7}Y%6  
RandomAccessFile oSavedFile; l\J
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long nPos; Z#%4QIz?  
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public FileAccessI() throws IOException !'[f!vsyM{  
{ ^dld\t:tV7  
this("",0); [P
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} )lE]DG!  
`#E1FB2M  
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public FileAccessI(String sName,long nPos) throws IOException {O[a+r.n  
{ N.l+9L0b  
oSavedFile = new RandomAccessFile(sName,"rw"); "xi)GH]H_  
this.nPos = nPos; )L<NW{  
oSavedFile.seek(nPos); n'K,*  
} 3t)07(x_B  
P_ U[OM\  
!SMIb(~[z  
public synchronized int write(byte[] b,int nStart,int nLen) 4,`Yx s)%  
{ vg5i+ry<  
int n = -1; @/g%l1$`  
try{ aTxss:7]  
oSavedFile.write(b,nStart,nLen); P?\IlziCB  
n = nLen; q{nNWvL  
} /q0[T{Wz$  
catch(IOException e) M|w;7P}  
{ ]%!:'#  
e.printStackTrace (); M| :wC  
} _Y?p =;  
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eF823cH2x_  
return n; *0^!%Y'/4  
} T8bk\\Od  
/PafIq  
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} ~xerZQgc  
|Ah'KpL8W  
ZEYT17g]  
/* &!SdO<agZ  
**SiteInfoBean.java p8aGM-+40W  
*/ <%Zg;]2H`  
package NetFox; _Ryt|# y  
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public class SiteInfoBean { .B_LQ;0:   
jdqVS@SD  
JR] /\(  
private String sSiteURL; //Site's URL 2~h! ouleY  
private String sFilePath; //Saved File's Path fkbHfBp[(A  
private String sFileName; //Saved File's Name M_lQ^7/  
private int nSplitter; //Count of Splited Downloading File &mXJL3iN  
z~\a]MB  
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public SiteInfoBean() P MV;A{T  
{//nSplitter的缺省值为5 Xn@\p5<  
//default value of nSplitter is 5 hLK5s1#K  
this("","","",5); c5C 2xE}T  
} n;+CV~  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) v'na{"  
{ $a.fQ<,\X  
sSiteURL= sURL; k<(G)7'gm  
sFilePath = sPath; #;~`+[y?\  
sFileName = sName; (cAWT,  
this.nSplitter = nSpiltter; 50kjX}  
gT8Q:8f:  
8S/SXyS  
} {BPNb{dBKr  
?&A)%6` ~  
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public String getSSiteURL() p)2 !_0  
{ }%2hBl/
  
return sSiteURL; WRrCrXP  
}
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}.*"ezaZw  
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public void setSSiteURL(String value) +U9m  
{ b* (~8JxZ  
sSiteURL = value; nYy%=B|>  
} f4[fXP;A  
M:TN^ rA|  
0>{&8:  
public String getSFilePath() KTLq~Ru  
{ fz>3  
return sFilePath; VS` tj  
} u*}[fQ`aF  
]6s7?07m4  
8.JFQ/)i  
public void setSFilePath(String value) ^V6cx2M  
{ 76 nrDE  
sFilePath = value; +\Uq=@  
} 4f~ c#0?  
/Q]6"nY  
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public String getSFileName() ]]Bqte  
{ l$_q#Kd  
return sFileName; c+S<U*  
} J)o.@+Q}  
c?(;6$A  
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public void setSFileName(String value) skaPC#u  
{ k|uW~I)  
sFileName = value; 80m<OW1  
} fhwJ  
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public int getNSplitter()  _"0,  
{ KYw~(+gHv2  
return nSplitter; ~t=73fwB  
} t.\<Q#bN#  
Cj/J&PDQ  
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public void setNSplitter(int nCount) 9f=L'{  
{ x)}.@\&%  
nSplitter = nCount; &JUHm_wd&S  
} fI<|]c}P&J  
} 7l%]O}!d)  
9N[(f-`  
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/* O~P1d&:L  
**Utility.java xxy (#j$  
*/ b?^CnMO  
package NetFox; CU`yi.)T{  
]9A@iA  
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public class Utility { xVnk]:c  
)t#>fnN  
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public Utility() !#[B#DZc(  
{ |7CFm  
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} ^QG;:.3v  
h4,g pV>t  
//线程睡眠 q9 SV<qg  
public static void sleep(int nSecond) ~7 w"$H8  
{ aw\0\'}  
try{ )swu~Wb}U@  
Thread.sleep(nSecond); X;/5Niv32q  
} F=g+R~F  
catch(Exception e) n9H4~[JiC  
{ N+N98~Y`P  
e.printStackTrace (); Dve+ #H6N  
} "L9yG:  
} #@UzOQ>  
aam6R/
4  
//日志 S"<"e\\}"_  
public static void log(String sMsg) ?9Hs,J  
{ ~bD'QMk  
System.err.println(sMsg); ?mi1PNps#  
} t,]E5,1  
xg.o7-^M  
.P:mYC  
public static void log(int sMsg) w<|Qezi3 w  
{ Z1dLC'/b]  
System.err.println(sMsg); VN/v]  
} }!_o
fe  
} wZnv*t_  
2kfX_RK  
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/* ,9.-A-Yw  
**TestMethod.java o%SD\zk  
*/ N|-'Fu  
package NetFox; ^[g7B"`K5  
Vh}F#~BrI  
H&*KpOL  
public class TestMethod { qP5'&!s&!  
bu:%"l  
`JAM]qB"  
public TestMethod() X/qLg+X  
{ ///xx/weblogic60b2_win.exe "i^< H  
try{ `^mY*Cb e  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); BM>'w,$KL  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); vuoD~=z  
SiteFileFetch fileFetch = new SiteFileFetch(bean); [/Vi*Z  
fileFetch.start(); oYmLJzCf  
} ;&} rO.0  
catch(Exception e){e.printStackTrace ();} ^Q9!DF m  
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} WNO!6*+  
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public static void main(String[] args) ;^DG P  
{ a,ZmDkzuv  
new TestMethod(); ;)XB'  
} Hs`j6yuc9  
} /'QfLW>6  
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