http断点续传简单实现（java)

/* Vc8w[oS  
**SiteFileFetch.java 5z.Y}  
*/ $GD Q1&Z  
package NetFox; u`*1OqU  
import java.io.*; 0\1g-kc!v  
import java.net.*; S""F58H n  
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public class SiteFileFetch extends Thread { B?d+^sz]  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ]0")iY_  
long[] nStartPos; //开始位置 E
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long[] nEndPos; //结束位置 ,H/BW`rL]#  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 N.V5>2  
long nFileLength; //文件长度 $%1oZ{&M  
boolean bFirst = true; //是否第一次取文件 ] $F%  
boolean bStop = false; //停止标志 uOx"oR|  
File tmpFile; //文件下载的临时信息 BWkTQd<t  
DataOutputStream output; //输出到文件的输出流 z|<?=c2P  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） b:x~Jz#%2  
public SiteFileFetch(SiteInfoBean bean) throws IOException 8wCB}qC  
{  ,}^FV~  
siteInfoBean = bean; Rz<'&Z>;  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); "!#KQ''R  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); yi<H }&  
if(tmpFile.exists ()) q^}iXE~  
{ G,b*Qn5#  
bFirst = false; cj|Urt  
read_nPos(); EiPOY'  
} h\|T(597.  
else >4?735f=x  
{ 6"2IV  
nStartPos = new long[bean.getNSplitter()]; 8&y#LeM1TT  
nEndPos = new long[bean.getNSplitter()]; <,t6A?YoMP  
} Go7 oj'"  
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} i@ehD@.dH  
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public void run() 3g3Znb  
{ Ee{Y1W  
//获得文件长度 rDLgQ{Sea  
//分割文件 @,q<CF@Y  
//实例FileSplitterFetch >%c>R'~h  
//启动FileSplitterFetch线程 l(Uwci  
//等待子线程返回 rrs0|=  
try{ pvdCiYo1r  
if(bFirst) 50Ov>(f@7  
{ C|S~>4`  
nFileLength = getFileSize(); \[]4rXZN0  
if(nFileLength == -1) N}'2GBqfU4  
{ I$ ?.9&.&  
System.err.println("File Length is not known!"); =<r1sqf  
} XJA];9^  
else if(nFileLength == -2) Z1U@xQj  
{ I(qFIV+HR  
System.err.println("File is not access!"); "8\2w]"  
} Lr*\LP6jx3  
else [$`%ve  
{ .|KBQMI  
for(int i=0;i<nStartPos.length;i++) /Uni6O)oc  
{ OyIIJ!(  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); dlioaYc  
} d*LW32B@  
for(int i=0;i<nEndPos.length-1;i++) zCmx1Djz  
{ .i3_D??  
nEndPos = nStartPos[i+1]; xC 4L`\  
} m(^nG_eX  
nEndPos[nEndPos.length-1] = nFileLength; /PEL[
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} :CP,DO
 
} ka*#O"}L8  
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WIw*//nw  
//启动子线程 5p~hUP]tT  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; SnY{|  
for(int i=0;i<nStartPos.length;i++) sV]I]DR  
{ D/Py?<n-B  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 2~%^y6lR  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), *_K*GCy  
nStartPos,nEndPos,i); /1b7f'  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); /sdZf
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fileSplitterFetch.start(); sE[ Yg8yAt  
} h*\u0yD)  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), [-VIojs+u  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); @jKB[S;JSn  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", "-Wb[*U;  
nEndPos = " + nFileLength); f7&9IW`7F^  
// fileSplitterFetch[nPos.length-1].start(); c6VyF=2q  
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">vi=Tr  
//等待子线程结束 #GzowI'  
//int count = 0; 9u%(9Ae  
//是否结束while循环 Dv~jVIXu  
boolean breakWhile = false; @DSKa`  
!1/F71l DX  
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while(!bStop) ]l,,en5V  
{ f'TEua_`  
write_nPos(); v4F+^0?  
Utility.sleep(500); P7$/yBI U  
breakWhile = true; dd*p_4;  
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for(int i=0;i<nStartPos.length;i++) =X7_!vSv  
{ $ByP 9=|  
if(!fileSplitterFetch.bDownOver) a`>H69(bU  
{ }ldpudU  
breakWhile = false; KCnm_4  
break; 6i@* L\ Dl  
} -s]@8VJA"  
} M[(
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if(breakWhile) $CZ'[`+  
break; <T]ey  
"egpc*|]  
?/8V%PL~$  
//count++; w^NQLV S  
//if(count>4) ~7m+N)5  
// siteStop(); "C
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} -,2CMS#N  
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/y(0GP4A  
System.err.println("文件下载结束！"); q}W})  
} )W&{OMr  
catch(Exception e){e.printStackTrace ();} W:K'2j  
} PlCj<b1D:  
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K|I<kA~!H  
//获得文件长度 |q
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public long getFileSize() /*MioaQB}p  
{ ]'pL*&"X  
int nFileLength = -1; M~~)tJYsu  
try{ t(jE9t|2e6  
URL url = new URL(siteInfoBean.getSSiteURL()); w"C,oo3  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); M{4XNE]m  
httpConnection.setRequestProperty("User-Agent","NetFox"); l z-I[*bA  
}
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'  
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int responseCode=httpConnection.getResponseCode(); }_5R9w]"  
if(responseCode>=400) Udq!YXE0  
{ \>X!n2rLZe  
processErrorCode(responseCode); x,ZF+vE  
return -2; //-2 represent access is error w^U{e xo  
} [v\m)5  
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String sHeader; SmIcqM  
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for(int i=1;;i++) 6&il>  
{ @_1cY#!  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); m.<u!MI  
//Utility.log(in.readLine()); Qxk& J  
sHeader=httpConnection.getHeaderFieldKey(i); o4wSt6gBcJ  
if(sHeader!=null) jcb&h@T8kv  
{ |gIE$rt-~W  
if(sHeader.equals("Content-Length")) 5{
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{ O8SE)R~  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); _ j`tR:  
break; SZ}=~yoD(  
} k81%$E  
} ESYF4-d+  
else V@[C=K
  
break; {Wu[e,p  
} n4y]h  
} fP\q?X@]E  
catch(IOException e){e.printStackTrace ();} 8KYIHw  
catch(Exception e){e.printStackTrace ();} 8QoxU" c&  

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Utility.log(nFileLength); .ws86stFSb  
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return nFileLength; C511hbF  
} G? XS-oSv  
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//保存下载信息（文件指针位置） 1GqSY|FSGp  
private void write_nPos() Ka_;~LS>(  
{ Fk^N7EJ:$  
try{ *UJ4\  
output = new DataOutputStream(new FileOutputStream(tmpFile)); }>d  
output.writeInt(nStartPos.length); }}i'8  
for(int i=0;i<nStartPos.length;i++) G]4Ca5;Z!N  
{ *} ?  
// output.writeLong(nPos); n,2   
output.writeLong(fileSplitterFetch.nStartPos); =^i K^)  
output.writeLong(fileSplitterFetch.nEndPos); mEsb_3?#+  
} D:f=Z?L)>  
output.close(); |`t 6lVO,Z  
} X%3?sH  
catch(IOException e){e.printStackTrace ();}
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catch(Exception e){e.printStackTrace ();} 
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} cR_pC 9z  
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//读取保存的下载信息（文件指针位置） R TpNxr{[  
private void read_nPos() P^Owgr=Y  
{ ;81,1 Ie<~  
try{ q\~ #g.}  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); -z0;4O (K]  
int nCount = input.readInt(); iER@_?  
nStartPos = new long[nCount]; tH44\~  
nEndPos = new long[nCount]; >6HGh#0(p  
for(int i=0;i<nStartPos.length;i++) ;RRw-|/Wm  
{ 
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nStartPos = input.readLong(); zX4RqI  
nEndPos = input.readLong(); N+@ Ff3M  
} %^L{K[}  
input.close(); w.a9}GC  
} ,(pp+hNq  
catch(IOException e){e.printStackTrace ();} 3h d30o  
catch(Exception e){e.printStackTrace ();} 6#!CBY^{  
} -(]CFnD_N  
f!`?_  
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private void processErrorCode(int nErrorCode) G(TFv\`vH  
{ b&mA1w[W]  
System.err.println("Error Code : " + nErrorCode); #Pp:H/b  
} Rd5_{F  
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}b&lHr'Uw  
//停止文件下载 ?VmgM"'md  
public void siteStop() oV0T   
{ 9K/EteS
 
bStop = true;  2Y23!hw  
for(int i=0;i<nStartPos.length;i++)
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fileSplitterFetch.splitterStop(); 5dI=;L>D  
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} XhHgXVVGG<  
} OyF=G^w  
//负责部分文件的抓取 h_[
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**FileSplitterFetch.java }!oEjcX'  
*/ .i I{  
package NetFox; T+ZA"i+   
$3G^}A"  
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import java.io.*; 3Iv^  
import java.net.*; KF_fz   
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/*T^7Y&  
public class FileSplitterFetch extends Thread { "TZY)\{L  
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String sURL; //File URL c '
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long nStartPos; //File Snippet Start Position 
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long nEndPos; //File Snippet End Position H.ksI;,  
int nThreadID; //Thread's ID uBx\xeI  
boolean bDownOver = false; //Downing is over $jg[6`L$  
boolean bStop = false; //Stop identical #Az#_0=  
FileAccessI fileAccessI = null; //File Access interface m0TVi]v  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Y b3ckktY  
{ rs{)4.I  
this.sURL = sURL; Sk cK>i.[  
this.nStartPos = nStart; X]
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this.nEndPos = nEnd; O
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nThreadID = id; q
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fileAccessI = new FileAccessI(sName,nStartPos);//定位 Zek@xr;]  
} WJhTU@'  
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public void run() gHBvQ1g  
{ 1fS&KO{a  
while(nStartPos < nEndPos && !bStop) >] 'oN  
{ {x_.QWe5  
0N$7(.  
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try{ LBCH7@V1yR  
URL url = new URL(sURL); >nghFm  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); S@HC$  
httpConnection.setRequestProperty("User-Agent","NetFox"); uI7n{4W*x  
String sProperty = "bytes="+nStartPos+"-"; w~b:9_reY  
httpConnection.setRequestProperty("RANGE",sProperty); $:F+Nf 8  
Utility.log(sProperty); \mc0fY  
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InputStream input = httpConnection.getInputStream(); LUMbRrD-  
//logResponseHead(httpConnection); iAu/t  
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byte[] b = new byte[1024]; Z)`)9]*  
int nRead; Kq3c Kp4  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) xR0T'@q  
{ I/Vw2  
nStartPos += fileAccessI.write(b,0,nRead); t^~vi'bB  
//if(nThreadID == 1)  @./h$]6  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); H~+A6g]T  
} ~i5YqH0  
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3Tl<ST\  
Utility.log("Thread " + nThreadID + " is over!"); \9VF)Y.ke  
bDownOver = true; Q6qW?*Y  
//nPos = fileAccessI.write (b,0,nRead); (4+P7Z,Nc  
} E{|B&6$[}  
catch(Exception e){e.printStackTrace ();} H`CID*Ji  
} V%oZT>T3  
} 0hemXvv1  
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//打印回应的头信息 k."p&  
public void logResponseHead(HttpURLConnection con) \~ D(ww  
{ WPL@
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for(int i=1;;i++) xak)YOLRV  
{ }L_YpG7  
String header=con.getHeaderFieldKey(i); Lb/GL\J)  
if(header!=null) p@Y=6Bw  
//responseHeaders.put(header,httpConnection.getHeaderField(header));
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Utility.log(header+" : "+con.getHeaderField(header)); ':vZ&  
else QhZg{v[d  
break; vV}w>Ap[  
} k8w\d+!v  
} 8z#Qp(he  
F^u12R)  
>NKJ@4Y  
public void splitterStop() m\`>N_4*9  
{ e2O6q05 ?Q  
bStop = true; WA`A/`taT  
} :-1|dE)U  
R/hIXO  
~lw9sm*2v2  
} *S.U8;*Xj  
5?7AzJl>  
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/* &?@C^0&QV  
**FileAccess.java S[Du >  
*//文件访问(定位，写) }D#:NlMp  
package NetFox; DzAZv/h76  
import java.io.*; ;V}:0{p
 
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public class FileAccessI implements Serializable{ 4VJUu`[  
3Z b]@n  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 d
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RandomAccessFile oSavedFile;  /|0-O''  
long nPos; BX >L7n  
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public FileAccessI() throws IOException hYW9a`Ht/  
{ }|DspO  
this("",0); 1t
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} !"L.gu-'  
m{/7)2.  
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public FileAccessI(String sName,long nPos) throws IOException YZol4q|ic  
{ y}?|+/ dN  
oSavedFile = new RandomAccessFile(sName,"rw"); OEW'bT)  
this.nPos = nPos; ETp?RWXX  
oSavedFile.seek(nPos); uZ+bo&  
} IzP,)!EE  
:7v'[b  
BQ-x#[%s  
public synchronized int write(byte[] b,int nStart,int nLen) &`r/+B_W  
{ V@ >(xe7  
int n = -1; Cr.YSWg)4  
try{ 0,%{
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oSavedFile.write(b,nStart,nLen); N,(!
 
n = nLen; 8z9{H  
} #{cy(&cz  
catch(IOException e) @aIgif+v  
{ @5>#<LV=E#  
e.printStackTrace (); cLtVj2Wb  
} /LD3Bb)O  
t3;Zx+Br  
}%|ewy9|CW  
return n; J&xZN8jW   
} .GrOdDK$ns  
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} '75T2Ud  
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`'YX>u/  
/* idI w7hi4  
**SiteInfoBean.java a1Fx|#! mq  
*/ $V~@w.
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package NetFox; Lljn\5!r<  
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public class SiteInfoBean { s)^/3a  

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private String sSiteURL; //Site's URL y* +y&  
private String sFilePath; //Saved File's Path Y}?8  
private String sFileName; //Saved File's Name ula
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private int nSplitter; //Count of Splited Downloading File ')m!48  
jP
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public SiteInfoBean() &2tfj(ms  
{//nSplitter的缺省值为5 TKDG+`TyZ  
//default value of nSplitter is 5 7N$2N!I(  
this("","","",5); \-\>JPO~<  
} B~Sj#(WEa  
&
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&uq.k{<p\  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) &K^0PzWWof  
{ EZUaYp~M  
sSiteURL= sURL; fQ<sq0'e\  
sFilePath = sPath; RZa/la*  
sFileName = sName; [|(|"dh@^H  
this.nSplitter = nSpiltter; mQ[$U  
<FT7QO$I  
/3b*dsYsl  
} SDnl^a  
2b"*~O;  
qE
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public String getSSiteURL() E7Cobpm  
{ 8U{D)KgS  
return sSiteURL; 5zl+M`  
} ;4F6 $T'I  
R/hf"E1  
r4yz{^G  
public void setSSiteURL(String value) eM7@!CdA9q  
{ vW+6_41ZM  
sSiteURL = value; `ecseBn3d  
} ({uW-%  
]Ry9{:  
NRRJlY S  
public String getSFilePath() _7c3=f83  
{ s(,S~  
return sFilePath; =ZgueUz,  
} iE%"Q? Q/  
x 
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~A0]vcP  
public void setSFilePath(String value) :'%6
  
{ 'Y?-."eKh  
sFilePath = value; X=)V<2WO  
} bLc5$U$!I  
CoN[Yf3\  
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public String getSFileName() ipSMmpB  
{ +H-=`+,  
return sFileName; Eb3ZM#  
} o_:v?Y>0  
)%(ZFn}   
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public void setSFileName(String value) oF%m
  
{ kg/B<w'  
sFileName = value; i VSNara  
} :5YIoC  
]N>ZOV,>  
#:)'D?,  
public int getNSplitter() )V1X
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{ t@%w:*&  
return nSplitter; ^~4]"J};M  
} N?\X2J1  
(Y1*Bs[l  
}\a#e^-xQ+  
public void setNSplitter(int nCount) is.t,&H4P]  
{ =EJ&=t  
nSplitter = nCount; ]7HR U6$  
} s:T%,xS  
} !3b& S4  
:.:^\Q0  
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/* GS;GJsAs  
**Utility.java pc`P;Eui  
*/ j<AOC?  
package NetFox; P{Nvt/%  
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public class Utility { {yn,u)@r9S  
, ZsZzZ#  
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public Utility() ff--y8h  
{ iI GK"}  
*|rdR2R!  
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} O&Y;/$w  
%ZVYgtk;*  
//线程睡眠 WjVBz   
public static void sleep(int nSecond) JVAyiNIH>M  
{ :H}iL*  
try{ (KQLh,h7  
Thread.sleep(nSecond); bT:u|/I  
} >8Oa(9n  
catch(Exception e) S_lGrk\j  
{ Fa("Gok[  
e.printStackTrace (); :6Ri% Nb  
} /|EdpHx0  
} 4D65VgVDM  
1*O|[W  
//日志 0]d;)_`@  
public static void log(String sMsg) [YvS#M3T  
{ M9"Bx/  
System.err.println(sMsg); U9 iI2$  
} H,> }t S  
d) -(C1f  
jcCAXk055  
public static void log(int sMsg) b4L7M1l  
{ 196aYLE  
System.err.println(sMsg); u
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} GQ(Y#HSq  
} jCqz^5=$  
teok*'b:  
J/]%zwDwS  
/* %" iX3  
**TestMethod.java }dc0ZRKgx  
*/ A
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package NetFox; E'6>3n  
"L>'X22ed  
N{Sp-J>  
public class TestMethod { @IG's-  
!)a_@d.;i  

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public TestMethod() Du_5iuMh  
{ ///xx/weblogic60b2_win.exe ay8]"sa  
try{ cAR `{%b  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); :Xw|v2z%3  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); -2.7Z`*(  
SiteFileFetch fileFetch = new SiteFileFetch(bean); VEps|d3,,  
fileFetch.start(); |\(uO|)ju  
} a`wjZ"}'[  
catch(Exception e){e.printStackTrace ();} 3kxo1eb  
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7Kw'Y8  
} 4[lFurH  
!2t7s96  
I%d=c0>%  
public static void main(String[] args) -y.cy'$f  
{ >LBA0ynh {  
new TestMethod(); e-dkvPr  
} a_N7X  
} ]B/>=t"E  
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