http断点续传简单实现（java)

/* )-7(Hv
1  
**SiteFileFetch.java A UO0  
*/ d`rDEa
 
package NetFox; _KlPbyLU  
import java.io.*; Uu<sntyv  
import java.net.*; 9HBx[2&  
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public class SiteFileFetch extends Thread { ,@j&q  
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SiteInfoBean siteInfoBean = null; //文件信息Bean @C6DOB  
long[] nStartPos; //开始位置 Ay. q
)  
long[] nEndPos; //结束位置 2LK*Cv[  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 {s^n|b}  
long nFileLength; //文件长度 r_2VExk  
boolean bFirst = true; //是否第一次取文件 D_`)T;<Sp  
boolean bStop = false; //停止标志 0DjBqh$  
File tmpFile; //文件下载的临时信息 fxCPGj  
DataOutputStream output; //输出到文件的输出流 <Ucfd G&Lp  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） &ppZRdq]  
public SiteFileFetch(SiteInfoBean bean) throws IOException -)c"cgx.  
{ MhXm-<4  
siteInfoBean = bean; +]2~@=<@  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Kwmo)|7uPU  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); %.}  
if(tmpFile.exists ()) i
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{ |r!Qhb
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bFirst = false; HGMH g  
read_nPos(); {.[,ee-)9  
} yru}f;1  
else FKTP0e7=9  
{ s.Ic3ITd,  
nStartPos = new long[bean.getNSplitter()]; s~'C'B?  
nEndPos = new long[bean.getNSplitter()]; "pJEzC  
} <cd%n-  
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} 1T^L) %&p_  
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public void run() nqW:P$  
{ L{ ^@O0S  
//获得文件长度 fu;B?mIn  
//分割文件 8-#2?=  
//实例FileSplitterFetch |I<-x)joIK  
//启动FileSplitterFetch线程 (9lx5  
//等待子线程返回 {N`<e>A]{  
try{ y.NArN|%  
if(bFirst) {;~iq  
{ soCHwiE  
nFileLength = getFileSize(); u 9TlXn  
if(nFileLength == -1) 3`!KndY1  
{ `cRB!w=KHV  
System.err.println("File Length is not known!"); nlnJJM&J$  
} jv^L~<u  
else if(nFileLength == -2) 73<yrBxp  
{ Kt0Tuj@CY  
System.err.println("File is not access!"); 6XU5T5+P^  
} )SLs  [  
else N*-Z Jv  
{ &1Iy9&y  
for(int i=0;i<nStartPos.length;i++) {NDe9
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{ xz'd5 re%  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); tfQq3#  
} %05a>Rf&  
for(int i=0;i<nEndPos.length-1;i++) AXI:h"so  
{ 
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nEndPos = nStartPos[i+1]; '1nU[,Wj  
} e8v=n@0  
nEndPos[nEndPos.length-1] = nFileLength; y?hW#l~#X  
} xUoY|$fI  
} -qF|Y f  
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>$F]Ss)$  
//启动子线程 B.jYU  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; B/}>UHM  
for(int i=0;i<nStartPos.length;i++) 6Fb~`J~s  
{ Y6a|\K|  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), E]Q)pZ{Jb  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), \:7EKzQ  
nStartPos,nEndPos,i); .|-y+9IP  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); yL-L2  
fileSplitterFetch.start(); ?CDq^)T[  
} 8E{>czF"  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), -%|I  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Q!v[b{]8  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 9~yuyv4$  
nEndPos = " + nFileLength); ZxQP,Ys_Y  
// fileSplitterFetch[nPos.length-1].start(); 5$X{{j2  
1\uS~RR  
htaLOTO;A  
//等待子线程结束 aT#|mk=\  
//int count = 0; XLT<,B}e  
//是否结束while循环 &@+;]t  
boolean breakWhile = false; \\JXY*DA:+  
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while(!bStop) v#xF;@G  
{ M;R>]wP"V  
write_nPos(); q-#fuD^  
Utility.sleep(500); "/5b3^a  
breakWhile = true; lRb)Tz6SE  
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for(int i=0;i<nStartPos.length;i++)
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{ "2J;~  
if(!fileSplitterFetch.bDownOver) =[kv@
p  
{ 9}N*(PI  
breakWhile = false; @Klj!2cv$  
break; &BkNkb0  
} J']W7!p  
} novZ<?7 5;  
if(breakWhile) -84Z8
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break; A:f+x|[  
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//count++; 2k_Bo~.  
//if(count>4) 4/b#$o<I?  
// siteStop(); 0Ko,S(M_  
} @OpcS>:R  
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System.err.println("文件下载结束！"); dx^3(#B  
} aozk,{9-  
catch(Exception e){e.printStackTrace ();} y$WS;#  
} Nn$$yUkMX  
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99 ["I:  
//获得文件长度 sb1/4u/W  
public long getFileSize() *;Vq0a!  
{ *M{1RMc  
int nFileLength = -1; \vI_%su1N  
try{ rP'oUV_  
URL url = new URL(siteInfoBean.getSSiteURL()); zMa`olTZ  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); (/%}a`2#o  
httpConnection.setRequestProperty("User-Agent","NetFox"); 1g;3MSn~  
1
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>,DR{A2hSB  
int responseCode=httpConnection.getResponseCode(); 4AGc2e'u  
if(responseCode>=400) 8)i\d`  
{ m>iuy:ti  
processErrorCode(responseCode); vjHbg#0%  
return -2; //-2 represent access is error _2|,j\f;L  
} >@t]M`#&h
 
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String sHeader; +G?3j,a\  
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for(int i=1;;i++) , 7}Ri  
{ ^!A{ 4NV  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Cnn,$R=/s  
//Utility.log(in.readLine()); NWKD:{  
sHeader=httpConnection.getHeaderFieldKey(i); 7
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if(sHeader!=null) &B))3WFy  
{ L|c01  
if(sHeader.equals("Content-Length")) ;N)qNiJY  
{ QII>XJ9  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); [P 8e=;  
break; le*pd+>j  
} &)rm
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} RNm/&F1C$  
else 9;:
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break; -1fT2e  
} I+}h+[W  
} HIF.;ImG^  
catch(IOException e){e.printStackTrace ();} |`,%%p|T%  
catch(Exception e){e.printStackTrace ();} (Y-
7B  
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Utility.log(nFileLength); 3Y>!e#  
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return nFileLength; 1,Y-_e)  
} +
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//保存下载信息（文件指针位置） 0&Zm3(}  
private void write_nPos() j:rGFd  
{ e3&R3{  
try{ u PjJ>v  
output = new DataOutputStream(new FileOutputStream(tmpFile)); mL ]zkD_  
output.writeInt(nStartPos.length); |_Z(}% <o  
for(int i=0;i<nStartPos.length;i++) m\[r6t]V  
{ ?PLf+S  
// output.writeLong(nPos); @"];\E$sI  
output.writeLong(fileSplitterFetch.nStartPos); zuXJf+]  
output.writeLong(fileSplitterFetch.nEndPos); IrJCZsk  
} !fjDO!,!  
output.close(); rD fUTfv|Q  
} "4|D"|wI)  
catch(IOException e){e.printStackTrace ();} L3,p8-d9Z  
catch(Exception e){e.printStackTrace ();} Fd9ypZs  
} `q".P]wtKN  
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//读取保存的下载信息（文件指针位置） +.:- :  
private void read_nPos() QVsOB$  
{ `~
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try{ EE=!Y NP]  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); LW 8LD|@  
int nCount = input.readInt(); { owK~  
nStartPos = new long[nCount]; s,)Z8H  
nEndPos = new long[nCount]; p<: b
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for(int i=0;i<nStartPos.length;i++) ^giseWR(  
{ sFuB[ JJ}  
nStartPos = input.readLong(); &;DK^ta*P  
nEndPos = input.readLong(); ,C1}gPQ6<  
} Q,S~+bD(z  
input.close(); JmjqA Dex  
} fucG
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catch(IOException e){e.printStackTrace ();} _o`+c wc  
catch(Exception e){e.printStackTrace ();} UJ* D  
} P>j^w#$n  
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T
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private void processErrorCode(int nErrorCode) 3copJS  
{ V(3^ev/  
System.err.println("Error Code : " + nErrorCode); agp`<1h9  
} |WwC@3)  
x]{
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z3x/Y/X$S  
//停止文件下载 3}~.#`QeY  
public void siteStop() -j9Wf=  
{ $P rji  
bStop = true; Mtq\xF,/+  
for(int i=0;i<nStartPos.length;i++) nI]8w6eCV  
fileSplitterFetch.splitterStop(); &y_Ya%Z3*e  
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} i7D[5!  
} L8R{W0Zr>!  
//负责部分文件的抓取 W cOyOv  
**FileSplitterFetch.java rMr:\M]t  
*/ /5M0[C E  
package NetFox; S7a05NO  
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s R/z)U_  
import java.io.*; i
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import java.net.*; .Nk'y
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public class FileSplitterFetch extends Thread { YF8
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String sURL; //File URL T8^`<gr.  
long nStartPos; //File Snippet Start Position Mbm'cM&}  
long nEndPos; //File Snippet End Position 0nr5(4h  
int nThreadID; //Thread's ID ICdfak  
boolean bDownOver = false; //Downing is over ^k J>4  
boolean bStop = false; //Stop identical >G9YYt~  
FileAccessI fileAccessI = null; //File Access interface ibP IT!5c  
l6_dVK;s  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Phq"A[4=O  
{ Q6PaT@gs  
this.sURL = sURL; mP*Ct6628n  
this.nStartPos = nStart; 1VKu3  
this.nEndPos = nEnd; 56JxHQu  
nThreadID = id; 3QI.|;X  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 _.%U}U  
} E]O/'-
 
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public void run() Y6 <.]H  
{ vc%=V^)N7U  
while(nStartPos < nEndPos && !bStop) iV5S[uy72.  
{ v?Zo5uVoq  
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try{ 7!F -.kG  
URL url = new URL(sURL); dL]wu!wE  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); =odKi"-6  
httpConnection.setRequestProperty("User-Agent","NetFox"); 8'PK}heBU  
String sProperty = "bytes="+nStartPos+"-"; f"z;'  
httpConnection.setRequestProperty("RANGE",sProperty); }Uu#N H  
Utility.log(sProperty); S2jn  pf}  
,!O]c8PcU  
:85QwN]\  
InputStream input = httpConnection.getInputStream(); + )n}n5  
//logResponseHead(httpConnection); ZaYUf  
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byte[] b = new byte[1024]; NTo[di\_  
int nRead; Wl7S<>hg4  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Hqtv`3g  
{ Q@1SqK#-DQ  
nStartPos += fileAccessI.write(b,0,nRead); Vx{   
//if(nThreadID == 1) #-i#mbZ e  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ?bPW*A82{q  
} ]O>AD6P  
mp)+wZAN&  
aoQ$"PF9  
Utility.log("Thread " + nThreadID + " is over!"); z=TOGP(  
bDownOver = true; 1Va=.#<  
//nPos = fileAccessI.write (b,0,nRead); naM~>N  
} u#y#(1 =  
catch(Exception e){e.printStackTrace ();} Qz89=#W  
} |/ji
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} h=qT@)h1>  
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//打印回应的头信息 AB{zkEuK  
public void logResponseHead(HttpURLConnection con) YG /@=Z.  
{ )~Gn7  
for(int i=1;;i++) [mQdc?n\  
{ ]9PG"<^k  
String header=con.getHeaderFieldKey(i); `8r$b/6  
if(header!=null) G3 |x%/Fbp  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ^ir)z@P?V  
Utility.log(header+" : "+con.getHeaderField(header)); ~<-mxOe  
else t3!OqM  
break; t(dVd%  
}
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} %|%eGidu  
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public void splitterStop() 4AKr.a0q  
{ "h #
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bStop = true; j0j!oj)7I  
} l p(D@FT  
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} LF @_|oI  
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/* 73]8NVm  
**FileAccess.java ^{{a v?h  
*//文件访问(定位，写) (w{T[~6  
package NetFox; :8]8
[  
import java.io.*; / Y
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_5H~1G%q  
h_{f_GQ"  
public class FileAccessI implements Serializable{ D(;+my2  
wViTMlq  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 iC5HrOl6U  
RandomAccessFile oSavedFile; $8i`h}AM  
long nPos; E N%{ $  
ErJ/h?+  
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public FileAccessI() throws IOException ,(a~vqNQW3  
{ !mTq6H12 !  
this("",0); Lui6;NY  
} {lH'T1^m  
:IBP "  
;l~a|KW0  
public FileAccessI(String sName,long nPos) throws IOException -seLa(8F  
{ !yPy@eP~  
oSavedFile = new RandomAccessFile(sName,"rw"); Y.) QNTh  
this.nPos = nPos; !L8q]]'XM  
oSavedFile.seek(nPos); l?2  
} u6F>o+Td)  
R6BbkYWrX  
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public synchronized int write(byte[] b,int nStart,int nLen) 'G~i;o 2  
{ _S7?c^:~  
int n = -1; _AFje  
try{ T0")Ryu  
oSavedFile.write(b,nStart,nLen); vD9\i*\2  
n = nLen; v0dzM/?*  
} p0 X%^A,4  
catch(IOException e) y>x"/jzF#  
{ <uv`)Q9  
e.printStackTrace (); %6 Av1cv  
} u-|%K.A  
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K=o {  
return n;
3))CD,|  
} Ewp2 1  
&hkD"GGe  

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} ~`&4?c3p  
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/* "lu^  
**SiteInfoBean.java +58^{_k+%  
*/ .eg'Z@o  
package NetFox; ~y"R{-%uS  
SF*mY=1  
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public class SiteInfoBean { Ncbe{}<md  
^_Lnqk6  
FT~c|ep.  
private String sSiteURL; //Site's URL  *\xRNgEQ  
private String sFilePath; //Saved File's Path XchD3p+uB  
private String sFileName; //Saved File's Name @H$am  
private int nSplitter; //Count of Splited Downloading File Od;k}u6;<  
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public SiteInfoBean() d7b`X<=@s  
{//nSplitter的缺省值为5 M5+R8ttc  
//default value of nSplitter is 5 Q+K]:c  
this("","","",5); <ZZfN@6  
} SGZYDxFC@  
c/bT5TIEWs  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ?:60lCqj  
{ UV;I6]$}A7  
sSiteURL= sURL; $<Gt^3e  
sFilePath = sPath; :%mlsNw  
sFileName = sName; wjX0r7^@  
this.nSplitter = nSpiltter; nY1PRX\  
[*)2Ou  
u SZfim@Z7  
} EiM\`"o  
mXJG &EA  
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public String getSSiteURL() S?v;+3TG  
{ 2i6P<&@  
return sSiteURL; }o GMF~  
} O[1Q#  
?j!/Hc/b4  
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public void setSSiteURL(String value) <Vyl*a{%  
{ YL;*%XmAG  
sSiteURL = value; 'zt}\ Dt  
} pDr/8HEh  
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public String getSFilePath() >
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{ \@6w;tyi  
return sFilePath; ,+n{xI2  
} m:;`mBOc3  
QA!'p1{#  
[9CBTSr  
public void setSFilePath(String value) BXl Y V"  
{ $*0XWrE  
sFilePath = value; pi*?fUg!W  
} ug`Jn&x!  
kf",/?s2Z  
_32 o7}!x  
public String getSFileName() /LCRi  
{ 1NlpOVq:)  
return sFileName; )!`>Q|]}Zd  
} Q@l.p-:^U  
t+WUz#i"  
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public void setSFileName(String value) #5IfF~*i  
{ ( v=Z$#l  
sFileName = value; Mg^3Y'{o  
} CM%
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1,G f;mcQ  
{ r8H5X  
public int getNSplitter() H 4W4#\M  
{ _ <pO<S  
return nSplitter; #J c)v0_  
} :+S~N)0j^  
+Xr87x;  
 %?:eURQ  
public void setNSplitter(int nCount) ..ht)Gex  
{ o{ \r1<D  
nSplitter = nCount; Q(YQ$i"S  
} yy3-Xu4  
} Z
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=dI2j@}c  
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/* `zRm
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**Utility.java {[.<BU-  
*/ SA16Ng  
package NetFox; 7j L.\O  
8(A+"H(  

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public class Utility { vwQ6=  
! .|\}=[e  
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public Utility() )[hQK_e]  
{ 4 '6HX#J  
R k).D6  
({AqL#x`u  
} P ".[=h  
ueazAsk3g  
//线程睡眠 5}t}Wc8  
public static void sleep(int nSecond) m2"~
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{ 9nPc>O$  
try{ PKM8MYvo  
Thread.sleep(nSecond); mN:p=.& <  
} r/vRaOg>X  
catch(Exception e) @eGJ_
J  
{ Xy(o0/7F9  
e.printStackTrace (); Bzw!,(u/ "  
} sh%snLw  
} nZ 0rxx[V?  
Sc zYL?w^  
//日志 }XiV$[xHd  
public static void log(String sMsg) >~sAa+Oxi  
{ 5h2@n0  
System.err.println(sMsg); "NamP\hj  
} ]D;X"2I2'b  
^sp+ sr :  
'bXm,Ed  
public static void log(int sMsg) _cY!\'  
{ &O5W  
System.err.println(sMsg); 6:(*
u{  
} 5@6%/='I q  
} [y}0X^9,E  
n~g,qEI;<x  
;U=RV&  
/* n%>c4*t  
**TestMethod.java 2%'iTXF  
*/ x05yU  
package NetFox; L)cy&"L|  
EVW{!\8[  
_BV'J92.  
public class TestMethod { `H5n_km  
h98_6Dw(]  
s^]F4'  
public TestMethod() S&A, Q'  
{ ///xx/weblogic60b2_win.exe X/_e#H0  
try{ Jbud_.h9  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); R)AFaP |  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); o!`.LL%  
SiteFileFetch fileFetch = new SiteFileFetch(bean); (=d%Bn$6b  
fileFetch.start(); 5JE8/CbH  
} }vRs n-E@  
catch(Exception e){e.printStackTrace ();} $q]:m+Fm
 
0Dj<-n{9  
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} )p&FDK#ob=  
d~](S<k  
7-"ml\z  
public static void main(String[] args) )&"l3*x  
{ :*aBiX"  
new TestMethod(); pm+_s]s,  
} 4#$~gTc@  
} ^mLZT*
  
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