http断点续传简单实现（java)

/* !b7'>b'J<1  
**SiteFileFetch.java 3@yTzaq6  
*/ *vRI)
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package NetFox; J`r,_)J"2  
import java.io.*; {,Bb"0 \  
import java.net.*; L-z;:Ztk  
\oB'  
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public class SiteFileFetch extends Thread { z9M.e.
  
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}. xrJ52Tz  
SiteInfoBean siteInfoBean = null; //文件信息Bean B.YMP;7>  
long[] nStartPos; //开始位置 B [+(r  
long[] nEndPos; //结束位置 2Io6s'  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 v\%B  
long nFileLength; //文件长度 rv}mD  
boolean bFirst = true; //是否第一次取文件 6QII&Fg  
boolean bStop = false; //停止标志 U=kx`j>  
File tmpFile; //文件下载的临时信息 ~M ,{ _  
DataOutputStream output; //输出到文件的输出流 5pM&h~M
 
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） `*NO_K  
public SiteFileFetch(SiteInfoBean bean) throws IOException 4bi NGl~  
{ z
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siteInfoBean = bean; h`5YA89  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); J%\
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tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); AfRW=&xdT  
if(tmpFile.exists ()) X&(<G  
{ N-2([
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bFirst = false; FjZc#\^9  
read_nPos(); E.J0fwyT  
} `ke3+%uj o  
else 9c6czirwR^  
{ skIiJ'db  
nStartPos = new long[bean.getNSplitter()]; bo@,4xw  
nEndPos = new long[bean.getNSplitter()]; ^kn^CI6  
} s.yq}Q  
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p^1zIC>F  
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} JiFA]M`^Q  
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public void run() N0Efw$u  
{ 2W^B{ZS;  
//获得文件长度 H
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//分割文件 M18qa,fK{  
//实例FileSplitterFetch +Edzjf~Tt  
//启动FileSplitterFetch线程 9u,8q:I.?  
//等待子线程返回 G'f9N^w  
try{ <4bz
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if(bFirst) j8G
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{ <S1??  
nFileLength = getFileSize(); -<qxO  
if(nFileLength == -1) :dP~.ZY7  
{ SY-ez91  
System.err.println("File Length is not known!"); i;o}o*=  
} $Y6I_U  
else if(nFileLength == -2) {L@+(I  
{ 0K<x=-cCB
 
System.err.println("File is not access!"); .,3Zj /  
} ^r
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else Rj[hhSx 2  
{ &<,SV^wag  
for(int i=0;i<nStartPos.length;i++) l~bKBz  
{ Jyj0Gco  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 6HoqEku/Q  
} [X,A'Q  
for(int i=0;i<nEndPos.length-1;i++) AR%hf  
{ "8N"Udu  
nEndPos = nStartPos[i+1]; C
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} R?cUy8?'S  
nEndPos[nEndPos.length-1] = nFileLength; _!n}P5  
} QR<`pmB~y  
} OJAx:&]3  
<lMg\T?K  
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//启动子线程 LA-_3UJx  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; B?LXI3sQZ  
for(int i=0;i<nStartPos.length;i++) q-3]jHChh  
{ ddsUz1%l  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 0$6*o}N%  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), b'i'GJBQ+$  
nStartPos,nEndPos,i); .~3kGf":  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); CRFCqmevR  
fileSplitterFetch.start(); v"Me{+  
} 6*IpA
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// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 0n3D~Xzd  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); XCDSmZ  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 9tn;L"#&N  
nEndPos = " + nFileLength); #G_F`&  
// fileSplitterFetch[nPos.length-1].start(); 6*u,c^a  
F|9+ +)  
Bv$UFTz  
//等待子线程结束 ;7Y[c}V1^  
//int count = 0; jM~Bu.7 i6  
//是否结束while循环 TyF{tuF  
boolean breakWhile = false; 2i\Q@h  
17}$=#SX  

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while(!bStop) =SAV|  
{ dpwD8Q< U  
write_nPos(); !@G)$g=<  
Utility.sleep(500); }j4
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breakWhile = true; #'@ilk/.  
P z ?m>>#  
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for(int i=0;i<nStartPos.length;i++) %}q.cV  
{ @6 /yu>%  
if(!fileSplitterFetch.bDownOver) xCWz\-;  
{ %aU4,j^],o  
breakWhile = false; xjo;kx\y^  
break; -gS"pE^1  
} jin db#)bz  
} B5ea(j  
if(breakWhile) wu)Wg-dT  
break; i9rS6<
V'  
A>=E{  
+4et7  
//count++; %,\=s.~1  
//if(count>4) xRum*}|4  
// siteStop(); !KcWH9  
} i|]7(z#OyI  
R(k}y,eh.`  
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System.err.println("文件下载结束！"); /b5>Qp  
} Z) Wnow  
catch(Exception e){e.printStackTrace ();} `0bP0^w  
} mN*?%t  

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tx"LeZZ  
//获得文件长度 x)SralWb  
public long getFileSize() m:uPEpcU  
{ yto[8;)_  
int nFileLength = -1; [:h5}  
try{ ;HNq>/{  
URL url = new URL(siteInfoBean.getSSiteURL()); c 6"Ib)  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ;au*V5a%  
httpConnection.setRequestProperty("User-Agent","NetFox"); ,zhJY ?sk  
2N5`'  
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int responseCode=httpConnection.getResponseCode(); :^i^0dC  
if(responseCode>=400) p[9s<lEh  
{ 7"4z+w  
processErrorCode(responseCode); -)v@jlg02  
return -2; //-2 represent access is error d(-EcY>?  
} \OQkZ.cU;  
R_ ZK0ar  
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String sHeader; c6&Q^p|CF  
0 Y>M=|  
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for(int i=1;;i++) B
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{ o.m:3!RW  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); B(_WZa!  
//Utility.log(in.readLine()); k()$:-V  
sHeader=httpConnection.getHeaderFieldKey(i); 0|c}p([~  
if(sHeader!=null) f>2MI4nMG  
{ r^0F"9eOL  
if(sHeader.equals("Content-Length")) +1rkq\{l  
{ 7b[wu~'( n  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 5'KA'>@  
break; aUc|V{Jp  
} pTJX""C  
} i
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else E5</h"1  
break; M
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} Z hd#:d  
} MSw$_d  
catch(IOException e){e.printStackTrace ();} %Ip*Kq-  
catch(Exception e){e.printStackTrace ();} GbI-SbE  
H1/?+N}(  
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Utility.log(nFileLength); YJ_\Ns+Ow  
zmI]cD@G  
*JX;|S  
return nFileLength; z//VlB  
} ?'s6Xmd  
s58C2  
:o46rBs  
//保存下载信息（文件指针位置） q?):oJ  
private void write_nPos() KC`q#&dt  
{ =LkR!R=  
try{ 'Gl&Pa1g?  
output = new DataOutputStream(new FileOutputStream(tmpFile)); kD5!}+y  
output.writeInt(nStartPos.length); }}&#|)Yq  
for(int i=0;i<nStartPos.length;i++) ^uBxgWIC  
{ ? *>]")[>  
// output.writeLong(nPos); *.#oxcll  
output.writeLong(fileSplitterFetch.nStartPos); >UDd @  
output.writeLong(fileSplitterFetch.nEndPos); - e"jw#B  
} .,0bE  
output.close(); =WIJ>#Go<  
} 1vzb8.  
catch(IOException e){e.printStackTrace ();} X]%itA  
catch(Exception e){e.printStackTrace ();} *v ?m6R=)h  
} A A^{B  
2ZcKK8X;7  
zK|i='XSf  
//读取保存的下载信息（文件指针位置） c(#;_Ve2P  
private void read_nPos() MUnEuhXTr  
{ [F!Y%Zp  
try{ w[tmCn
+  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); U8.7>ENnP&  
int nCount = input.readInt(); _>+8og/%@  
nStartPos = new long[nCount]; ]hos+;4p  
nEndPos = new long[nCount]; +{<#(}  
for(int i=0;i<nStartPos.length;i++) >-8cU_m7s  
{ 6;'dUGvH  
nStartPos = input.readLong(); d?wc*N3  
nEndPos = input.readLong(); rf~Y
6U?7  
} 8N&+7FK  
input.close(); 7%f&M>/  
} L){iA-k;Ec  
catch(IOException e){e.printStackTrace ();} Q7Iw[=;\  
catch(Exception e){e.printStackTrace ();} fGhn+8VfX  
} GZI`jS"lU  
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wX >*H  
private void processErrorCode(int nErrorCode) -Eu6U`"(  
{ ~5FW[_  
System.err.println("Error Code : " + nErrorCode); #Cpd9|  
} @+3kb.P%7  
wLc4Dm*V  
1 zw*/dp  
//停止文件下载 Ym%xx!9  
public void siteStop() ls@i".[  
{ h8Yx#4  
bStop = true; p sL?Y  
for(int i=0;i<nStartPos.length;i++) #(An6itl  
fileSplitterFetch.splitterStop(); P3$Q&^?  
OnQdq^UB  
>B]'fUt5a  
} 1`ayc|9BR  
} q$I:`&  
//负责部分文件的抓取 WSuw
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**FileSplitterFetch.java !;?+>R)h  
*/ nt*Hc1I  
package NetFox; R2Zgx\VV'  
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}=c85f~i  
import java.io.*; AbZKYF P  
import java.net.*; aDO!  
'%q$`KDb  
(L^]Lk x)  
public class FileSplitterFetch extends Thread { a~'a  
(=7Cs  
lOtDqb&  
String sURL; //File URL KQB
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long nStartPos; //File Snippet Start Position 0c}  }Q  
long nEndPos; //File Snippet End Position Z&;uh_EC  
int nThreadID; //Thread's ID *S2ypzwRZ,  
boolean bDownOver = false; //Downing is over [Xb@Wh:yG  
boolean bStop = false; //Stop identical nBk)WX&[K  
FileAccessI fileAccessI = null; //File Access interface uj :%#u  
` ,SiA-3*  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException v`M3eh@$A  
{ dKdj`wB  
this.sURL = sURL; d_IAs  
this.nStartPos = nStart; &mb{.=  
this.nEndPos = nEnd; Na:w]r:y  
nThreadID = id; ,7<f9 EVY  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 tQS5hwm*  
} : |>Gc39`t  
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public void run() O)[1x4U  
{ vM5k_D  
while(nStartPos < nEndPos && !bStop) 8ji_#og  
{ gLOEh6  
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try{ zAiXo
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URL url = new URL(sURL); rx]  @A  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); G K
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httpConnection.setRequestProperty("User-Agent","NetFox"); ?#fu.YE\  
String sProperty = "bytes="+nStartPos+"-"; ;qm D50:%  
httpConnection.setRequestProperty("RANGE",sProperty); Y'8?.a
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Utility.log(sProperty); 9jw\s P@  
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p,eTY[k?  
InputStream input = httpConnection.getInputStream(); Ft&]7dT{W  
//logResponseHead(httpConnection); B

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*{L)dW+:  
#3gp6*R  
byte[] b = new byte[1024]; dw*_(ys  
int nRead; XCBL}pNkR  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) >Wv;R2|  
{ A<??T[  
nStartPos += fileAccessI.write(b,0,nRead); h2XfC.f  
//if(nThreadID == 1) 7eAX*Kgt<_  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ,%M$0poKM  
} mWsI}2  
K~R`%r_  
z*a:L}$  
Utility.log("Thread " + nThreadID + " is over!"); / G7vwC  
bDownOver = true;  |'B7v i)  
//nPos = fileAccessI.write (b,0,nRead); d>mo~  
} NA~V
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catch(Exception e){e.printStackTrace ();} eQ]~dA8>  
} 5fd]v<  
} ~5}*
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//打印回应的头信息 ppVHLrUh  
public void logResponseHead(HttpURLConnection con) ;EP:
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{ }f6HYU  
for(int i=1;;i++) oYH^_V  
{ ,Ge
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String header=con.getHeaderFieldKey(i); .nx2";oi  
if(header!=null) ` 2V19
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//responseHeaders.put(header,httpConnection.getHeaderField(header)); oYm[V<nIl  
Utility.log(header+" : "+con.getHeaderField(header)); nH[yJGZYSA  
else Wa{`VS  
break; @eKec1<  
} ddJe=PUb  
} ! t?iXZ  
:%,:"  
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public void splitterStop() J;8IY=  
{ ,)Znb=  
bStop = true; Y,^@P  
} ).`1+b  
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} d,B:kE0Y  
sN9&,&W1  
s;01u_  
/* {#?N  
**FileAccess.java Ac2n  
*//文件访问(定位，写) {Tq_7,8  
package NetFox; LnH?dy  
import java.io.*; CYY=R'1:G{  
$QLcH;+7t  
Ch<[l8;K  
public class FileAccessI implements Serializable{ "&G/T ?4  
Ku5\]  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ,9zjFI  
RandomAccessFile oSavedFile; #P0&ewy  
long nPos; Whm,F^  
) l:[^$=,  
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public FileAccessI() throws IOException g| I6'K!<  
{ O;:mCt _H  
this("",0); z[L8
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} !Prg_6 `  
v$?+MNks  
| *2w5iR  
public FileAccessI(String sName,long nPos) throws IOException 1WxK#c-)  
{ $P/~rZ@M@  
oSavedFile = new RandomAccessFile(sName,"rw"); Vc\MV0lr  
this.nPos = nPos; rWa2pO  
oSavedFile.seek(nPos); !Qu"BF  
} &=] ~0$  
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public synchronized int write(byte[] b,int nStart,int nLen) r*2+xDoEi  
{ )rxX+k+b/  
int n = -1; I9_RlAd  
try{ ;g+N&)n  
oSavedFile.write(b,nStart,nLen); [+T.at  
n = nLen; 4xjPiHd<  
} h-q3U%R4}@  
catch(IOException e) [9evz}X  
{ %[Wh [zZy  
e.printStackTrace (); C~,a!qY  
} EE&K0<?T|:  
1"MhGNynB>  
riY~%9iV'  
return n; %*A0#F  
} .sh
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#rMlI3;  
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} _.tVSVp  
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/* 2=,lcWr  
**SiteInfoBean.java |W,& Hl7  
*/ } gyj0  
package NetFox; z+0I#kM"1  
md)c0Bg8~  
LG{,c.Qj*  
public class SiteInfoBean { %9KldcQ}~  
N7b8m?!  
{f3YsM;]C  
private String sSiteURL; //Site's URL 3%#3iZ=_  
private String sFilePath; //Saved File's Path +rd|A|hRq  
private String sFileName; //Saved File's Name vyNxT*,[K  
private int nSplitter; //Count of Splited Downloading File kbX8$xTM  
i1ixi\P{0  
6tgt>\y  
public SiteInfoBean() -`*a'p-=  
{//nSplitter的缺省值为5 ~7*.6YnI  
//default value of nSplitter is 5 6iVxc|Ia  
this("","","",5); 6M @[B|Q(  
} n4;.W#\  
}aa'\8  
Q 3hKk$Y  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) I667Gz$j5  
{ kJ'
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sSiteURL= sURL; :;t:H] f  
sFilePath = sPath; ^me-[ 5  
sFileName = sName; u%&`}g  
this.nSplitter = nSpiltter; dyz2.ZY~2  
Yg]-wQrH  
M8kPj8}{  
} +nrbShV  
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public String getSSiteURL() ~ (|5/ p7t  
{ d[@X%  
return sSiteURL; {j.bC@hWw  
} Ec3}_`  
| k&Ck  
\(?rQg@U  
public void setSSiteURL(String value) CM/H9Kz.  
{ $O&b``  
sSiteURL = value; 9&-dTayIz  
} zqimR#u  
cvn@/qBq*t  
B nFwlw  
public String getSFilePath() 1{)5<!9!l  
{ K[I=6  
return sFilePath; N]>=p.#j  
} zGb|)A~,  
F+YZE[h%  
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public void setSFilePath(String value) \j@OZ  
{ 1!xQ=DU"  
sFilePath = value; 6dq(T_eG  
} ne>pOK<vZ  
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(yH'{6g\  
public String getSFileName() )Kc<j!8-[  
{ $SlIr<'*"  
return sFileName; %f&/E"M  
} K0u|U`  
,;EIh}  
 :|>h7v  
public void setSFileName(String value) G)EU_UE9  
{ 0M_ DB=  
sFileName = value; h{)kQLuzT  
} ep!Rf:  
H[6:_**?o  
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public int getNSplitter() H*d9l2,KZS  
{ ]AINKUI0  
return nSplitter; k0OYJ/  
} Y+kfBvxyf  
-$pzl,^ h  
j@n)kPo,1  
public void setNSplitter(int nCount) k$
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{ Z+*9#!?J  
nSplitter = nCount; 9g9HlB&Ze  
} >~''&vdsk\  
} z6KCv(zvB  
:y'Ah#  
v"y-0$M  
/* A!od9W6  
**Utility.java 52@C9Q,  
*/ ]i|h(>QWP  
package NetFox; rJ`!:f  
p)KheLiZ  
&y\prip  
public class Utility { 1h^:[[!c  
m]'#t)B_m  
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public Utility() 0pZ4BZdT|  
{ {j{u6i  
8o3E0k1  
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} ..IfP@  
VpE*(i$  
//线程睡眠 ~8PZ5;g  
public static void sleep(int nSecond) L^r#o-H<  
{ GB23\
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try{ >@U*~Nz  
Thread.sleep(nSecond); ] ]u s %  
} GoJ.&aH $  
catch(Exception e) KI.q@zO6|  
{ ,kyJAju>  
e.printStackTrace (); .N,bIQnj  
} _'#n6^Us<  
} ayn)5q/z  
:">!r.Q  
//日志 Uf1!qP/H?  
public static void log(String sMsg) T(#J_Y  
{ R}-(cc%5  
System.err.println(sMsg); 4zXFuTr($  
} aHV;N#Lx3  
3(="YbZ  
qz"}g/;?  
public static void log(int sMsg) xipU8'ac/  
{ Jz\%%C  
System.err.println(sMsg); 6gL#C&  
} C(eTR1  
} a4mn*,  
4R#chQ  
?fQ'^agq  
/* @bi}W`  
**TestMethod.java RF`.xQ26=  
*/ S4Pxc ]!  
package NetFox; (9tX5$e6N  
EGGWrl}1  
4n#M  
public class TestMethod { .8 2P(}h  
XD!W: uvb  
]tim,7s  
public TestMethod() ?U%qPv:  
{ ///xx/weblogic60b2_win.exe >1.X*gi?-  
try{ dph{74Dc  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); '3R`lv   
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); $By<$  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 8^kGS-+^  
fileFetch.start(); /}((l%UE.  
} u0}vWkn\4  
catch(Exception e){e.printStackTrace ();} L 8c0lx}Nn  
B |5]Jm]  
kGH}[w  
} s%vis{2  
/
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^+*N%yr  
public static void main(String[] args) 5 )A1\  
{ *1ilkmL%  
new TestMethod(); >,v`EIg  
} eln)BW#  
} y|jl[pyg)  
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