http断点续传简单实现（java)

/* 0uu)0:  
**SiteFileFetch.java jG`,k*eUrJ  
*/ #.
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package NetFox; *]:J@KGf  
import java.io.*; 4I8QM&7  
import java.net.*; z&Xk~R*$  
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public class SiteFileFetch extends Thread { .hRtQU  
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SiteInfoBean siteInfoBean = null; //文件信息Bean NG8F'=<  
long[] nStartPos; //开始位置 K;ocs?rk/  
long[] nEndPos; //结束位置 !u;gGgQF  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 DQ@M?~1hp  
long nFileLength; //文件长度 biG :Xn  
boolean bFirst = true; //是否第一次取文件 qr(t_qR&  
boolean bStop = false; //停止标志 v7/k0D .  
File tmpFile; //文件下载的临时信息 $DdC|
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DataOutputStream output; //输出到文件的输出流 _jb&=f8  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类）
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public SiteFileFetch(SiteInfoBean bean) throws IOException +;,X?E]g  
{ TBZhL  
siteInfoBean = bean; |AXV4{j_i  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); [A'e7Do%'  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); WfHa  
if(tmpFile.exists ()) `>GXJ~:D["  
{ |\xTcS|d  
bFirst = false; .X5A7 m  
read_nPos();
r4ljA@L  
} X%5 `B2Wu  
else DVt^O[  
{ < lUpvr  
nStartPos = new long[bean.getNSplitter()]; l.(|&U~  
nEndPos = new long[bean.getNSplitter()]; xiV!\Z}  
} oI
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} $rJgBN  
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public void run() FOteNQTj  
{ Dw>)\\n{Kl  
//获得文件长度 `dWnu3r;  
//分割文件 7'gk=MQc  
//实例FileSplitterFetch ^%m{yf#  
//启动FileSplitterFetch线程 CfVL'  
//等待子线程返回 ,g4T>7`&U%  
try{ ~Kl"V%>  
if(bFirst) ,fhF-%Q!g  
{ ,M:[GuXD<  
nFileLength = getFileSize(); E@6gTx*  
if(nFileLength == -1) pWn]$HaoG  
{ ArScJ\/Nwv  
System.err.println("File Length is not known!"); hUX8j9N>  
} J*_^~t  
else if(nFileLength == -2) 7VskZbj\  
{ ?a*w6,y.  
System.err.println("File is not access!"); ;mg.} fI  
} H?FiZy*[Y  
else %zo 6A1Q;  
{ ^=a:{["@!  
for(int i=0;i<nStartPos.length;i++) s8'!1rHd  
{ aHb&+/HZ  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Vk*XiEfKm>  
} F+?i{$  
for(int i=0;i<nEndPos.length-1;i++) stMxlG"d  
{ J1w3g,  
nEndPos = nStartPos[i+1]; @$Yk#N;&(  
}  w%::
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nEndPos[nEndPos.length-1] = nFileLength; O9m sPb:  
} qu!x#OY+  
} F/,6Jh  
}x&XvI  
:5'hd^Q  
//启动子线程 HR?bnkv|id  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Qmb+%z  
for(int i=0;i<nStartPos.length;i++) y~Yv^'Epf  
{ -0BxZ AW=  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 9P,[MZ  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), &/:c?F?l  
nStartPos,nEndPos,i); +t&+f7  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ^hr# 1  
fileSplitterFetch.start(); I2pE}6q  
} xwW(WHdC]  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), (kyRx+gA  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); tOte[~,  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", U#- 5",X|  
nEndPos = " + nFileLength); \So)g)K  
// fileSplitterFetch[nPos.length-1].start(); .r&CIL>  
Nq^o8q_  
OoRg:"9{#  
//等待子线程结束  j=G  
//int count = 0; S,udpQ7  
//是否结束while循环 MxUQF?@6  
boolean breakWhile = false; ^CM@VmPp  
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while(!bStop) s<Nw)Ynw  
{ GMkni'pV  
write_nPos(); ,aq>9\pi  
Utility.sleep(500); N)a5~<fBG  
breakWhile = true; [Jjo H1E@  
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for(int i=0;i<nStartPos.length;i++) ^|vP").aQm  
{ :Ig9n:  
if(!fileSplitterFetch.bDownOver) &j/,8 Z*  
{ gNZ"Kr o6  
breakWhile = false; Snn4RB<(  
break; K6)IBV;
 
} @3 +   
} s jaaZx1  
if(breakWhile) A[`c+&  
break; QNv5CQ&  
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//count++; jq_4x[  
//if(count>4) W>c*\)Xk !  
// siteStop(); beT[7uVj_  
} ,%zE>^~  
#N'9F&:V$  
#Aj#C>  
System.err.println("文件下载结束！"); |oX9SUl  
} >HzTaXCR[  
catch(Exception e){e.printStackTrace ();} kp!(e0n  
} mi5bk>o  
vXSA_"0t  
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//获得文件长度 9"L!A,&'  
public long getFileSize() cg_tJ^vrY  
{ bP|-GCKM8  
int nFileLength = -1; e5lJ)_o  
try{ 6Bd:R}yZP7  
URL url = new URL(siteInfoBean.getSSiteURL()); hOs~/bM  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); /Tw $}8  
httpConnection.setRequestProperty("User-Agent","NetFox"); y1Wb/ d  
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int responseCode=httpConnection.getResponseCode(); lQt,(@7]  
if(responseCode>=400)
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{ LJ9#!r@H  
processErrorCode(responseCode); *13-)yfd  
return -2; //-2 represent access is error Q&PEO%/D  
} Y[
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#"H<k(-Cz  
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String sHeader; Q'j00/K  
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for(int i=1;;i++) D*_.4I  
{ e;"%h%'  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); [s%uE+``S  
//Utility.log(in.readLine()); >=1UhHFNI  
sHeader=httpConnection.getHeaderFieldKey(i); q%1B4 mF'  
if(sHeader!=null) b=L|GV@$  
{ JiXN"s^mcb  
if(sHeader.equals("Content-Length")) \TYH7wXDP  
{ %T;VS-f  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Qi9M4Yv  
break; N~(?g7  
} $UdFm8&  
} =;?Maexp3$  
else UVsF !0  
break; 92*"3)
  
} #,!/Cnqis  
} Rp}Sm,w(  
catch(IOException e){e.printStackTrace ();} y99|V39'  
catch(Exception e){e.printStackTrace ();} 9~l8Qa
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Utility.log(nFileLength); ),-MrL8c%  
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return nFileLength; Uo|T6N  
} DM(c :+K-  
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//保存下载信息（文件指针位置） r+h$]OJ  
private void write_nPos() U{9yfy  
{ E/>kvs%  
try{ -TNb=2en(  
output = new DataOutputStream(new FileOutputStream(tmpFile)); M-C>I;a  
output.writeInt(nStartPos.length); j[fY.>yt&  
for(int i=0;i<nStartPos.length;i++) 9t&m\J >8;  
{
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// output.writeLong(nPos); r+i=P_p  
output.writeLong(fileSplitterFetch.nStartPos); 4Jw_gOY&D  
output.writeLong(fileSplitterFetch.nEndPos); =UZQ` {  
} h)X"<a++N  
output.close(); }>'1Qg  
} 3lefB A7  
catch(IOException e){e.printStackTrace ();} 7x(z  
catch(Exception e){e.printStackTrace ();} .;;
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} y,$zSPJCi  
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//读取保存的下载信息（文件指针位置） wD $sKd  
private void read_nPos() [4\n(/  
{ l}9E0^AS  
try{ %I%OHs  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ~J|B  
int nCount = input.readInt(); CVGQ<,KVW  
nStartPos = new long[nCount]; 0G#s/u#  
nEndPos = new long[nCount]; 2zbV9Bhq  
for(int i=0;i<nStartPos.length;i++) `& ]H`KNa  
{ W JG8E7  
nStartPos = input.readLong(); :v8~'cZ  
nEndPos = input.readLong(); [R{%r^"2p  
} MtBoX*"  
input.close(); |OO2>(Fj  
} B3@\Ua)  
catch(IOException e){e.printStackTrace ();} ?w>-ya  
catch(Exception e){e.printStackTrace ();} b|u0a6  
} 4inMd![  
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private void processErrorCode(int nErrorCode) 7\EY&KI"0  
{ k\}\>&Zqu  
System.err.println("Error Code : " + nErrorCode); #CNK [y  
} ?;CMsO*q  
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//停止文件下载 L~&r.81  
public void siteStop() Og9:MFI  
{ unAu8k^  
bStop = true; fO 6Jug  
for(int i=0;i<nStartPos.length;i++) :lp V  
fileSplitterFetch.splitterStop();
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} a>BPK"K2  
} 1ac;6`  
//负责部分文件的抓取 ;hJz'&UWQ  
**FileSplitterFetch.java vALH!Kh  
*/ NrWgaPO)i  
package NetFox; 8\$u/(DX  
HkdBPMs79  
Vae=Yg=fw  
import java.io.*; e>!=)6[*  
import java.net.*; -=a,FDeR  
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3 cF4xUIZ  
public class FileSplitterFetch extends Thread { {# Vp`ji  
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String sURL; //File URL o$KW*aDp  
long nStartPos; //File Snippet Start Position }BJR/r  
long nEndPos; //File Snippet End Position b!c2j   
int nThreadID; //Thread's ID 4LkW`Sbm  
boolean bDownOver = false; //Downing is over bDT@E,cSi  
boolean bStop = false; //Stop identical ECr}7R%  
FileAccessI fileAccessI = null; //File Access interface
wlw`%z-B2  
s1%th"e [  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException {P!1VYs5  
{ ){$*<#&H  
this.sURL = sURL; 2dJP|T9H  
this.nStartPos = nStart; GVld]ioycG  
this.nEndPos = nEnd; '0 J*9  
nThreadID = id; \<W/Z.}/  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 !6*m<#Qm  
} -X_dY>>s  
VhLS*YiSY  
*dPG[ }  
public void run() e^yfoE<7  
{ Tga%-xr+  
while(nStartPos < nEndPos && !bStop) _DLELcH Y  
{ K7=>o*p  
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try{ 0N`N  
URL url = new URL(sURL);
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); @cu#rWiG  
httpConnection.setRequestProperty("User-Agent","NetFox");  SGK 5  
String sProperty = "bytes="+nStartPos+"-"; @|EWif|  
httpConnection.setRequestProperty("RANGE",sProperty); IH3Nk
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Utility.log(sProperty); H_FT%`iM  
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InputStream input = httpConnection.getInputStream(); m"GgaH3,  
//logResponseHead(httpConnection); _@OS,A  
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byte[] b = new byte[1024]; )LTX.Kg  
int nRead; K8RV=3MBLD  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) q0L\{  
{ U88gJ[$  
nStartPos += fileAccessI.write(b,0,nRead); o'K= X E  
//if(nThreadID == 1) *=X61`0  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); c'SjH".[  
} pMd!Jl#(N  
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Utility.log("Thread " + nThreadID + " is over!"); vOo-
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bDownOver = true; jx14/E+^  
//nPos = fileAccessI.write (b,0,nRead); HsKq/Oyk  
} u4|)A4n  
catch(Exception e){e.printStackTrace ();} 6G7+&g`  
} `Gh J)WA<  
} TgA>(HcO  
%#TAz7  
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//打印回应的头信息 HutQ
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public void logResponseHead(HttpURLConnection con) V-dyeb  
{ N"s"^}M\  
for(int i=1;;i++) @]etW>F_  
{ S/dj])g  
String header=con.getHeaderFieldKey(i); z||FmL{  
if(header!=null) Q7-'5s  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ;:/C.%d  
Utility.log(header+" : "+con.getHeaderField(header)); VUC_|=?dL  
else <Vl`EfA(  
break; 2TgS )  
} + cZC$lo  
} r4Xaa<  
|

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public void splitterStop() j\iNag(  
{ /9
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bStop = true; e5(c,,/  
} f.0HIc  
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\+"Jg/)ij  
} mbHMy[R  
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/* 4kR;K!@k  
**FileAccess.java `
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*//文件访问(定位，写) 8S5Q{[!  
package NetFox; KQ0f2?  
import java.io.*; =.l>Uw!  
f#-\*  
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public class FileAccessI implements Serializable{ P MI?PC[;  
\d3~kq3  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 WBR# Ux  
RandomAccessFile oSavedFile; E85TCS1  
long nPos; SNf~%B?`L  
58R.`5B  
+_jM$?:F}  
public FileAccessI() throws IOException O^8=Xj#}  
{ BZIU@^Q_Y[  
this("",0); sGE%zCB  
} yv: Op\;R  
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x]  
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public FileAccessI(String sName,long nPos) throws IOException h@J3+u<  
{ QcX&q%*0  
oSavedFile = new RandomAccessFile(sName,"rw"); kx;7/fH  
this.nPos = nPos; {asq[;]  
oSavedFile.seek(nPos); "whs
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} dh1 N/[  
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Pa"Kk9!o36  
public synchronized int write(byte[] b,int nStart,int nLen) 'j!n   
{ {XV'C@B  
int n = -1; M!X^2  
try{ w-C%,1F,/  
oSavedFile.write(b,nStart,nLen); L uW""P/  
n = nLen; ,$U~<Zd  
} RL H!f1cta  
catch(IOException e) 'T7Y5X80$j  
{ 70EH~  
e.printStackTrace (); K[x=knFO   
} `fl$ o6S/  
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return n; cucT|y  
} /lhk} y^  
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} 50a';!H  
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/* t_Rj1U  
**SiteInfoBean.java 9<kMxtk$  
*/ p*Yx1er1  
package NetFox; [ $"  
d[nz0LI|mk  
KHGUR(\Rd6  
public class SiteInfoBean {
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private String sSiteURL; //Site's URL AYfe_Dj  
private String sFilePath; //Saved File's Path N vTp1kI]  
private String sFileName; //Saved File's Name ^:,wk7  
private int nSplitter; //Count of Splited Downloading File 0QxBC7`qp  
*SlWA)9Y  
;jO+<~YP!  
public SiteInfoBean() (+<66 TO  
{//nSplitter的缺省值为5 lHHx D  
//default value of nSplitter is 5 THB[(3q  
this("","","",5); 7#X`D  
} rq\<zx]au  
[xQ.qZ[h&  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) hlz/TIP^N3  
{ 3(gOF&Uf9  
sSiteURL= sURL; [57`V&c5  
sFilePath = sPath; 8*|*@  
sFileName = sName; J HV  
this.nSplitter = nSpiltter; 6Q{OM:L/;.  
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z4zPR?%:  
} z46Sh&+  
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oa[O~z{~  
public String getSSiteURL() kf#S"[/E  
{ hzpl;Mj  
return sSiteURL; 2 zG;91^  
} %:Y(x$Qy  
J4 U]_|  
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public void setSSiteURL(String value) gA3f@7}d  
{ {XD':2E  
sSiteURL = value; _'^_9u G  
} 1N5lI97j  
KP$AT}D  
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public String getSFilePath() Vi
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{ fKtlfQG  
return sFilePath; OKk"S_`  
} !DHfw-1K  
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bQ&%6'ck  
public void setSFilePath(String value) E]S:F3  
{ q]*jT
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sFilePath = value; SwaPRAF  
} WMWUP ZsGS  
[$:L|V!{  
zz(EH<>  
public String getSFileName() $Zkk14  
{ rhly.f7N=A  
return sFileName; {+3g*s/HI  
} C}DIm&))  
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public void setSFileName(String value) BN&}g}N  
{ %?[0G,JG  
sFileName = value; ! CJ*zZ*  
} vo2GFo  
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public int getNSplitter() X|QokAR{$>  
{ hb
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return nSplitter; 4^d).{&X  
} A..`?oGj  
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public void setNSplitter(int nCount) og&h$<uOZt  
{ cqW(9A|8  
nSplitter = nCount; y0/FyQs  
} Y]uVA`%"b  
} ]mgpd}Y  
$H]NC-\+>  
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/* 8pp;" "b  
**Utility.java b*{UO  
*/ :Gx5vo  
package NetFox; ]<r.{EJ  
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public class Utility { J8Vzf$t};  
{K?e6-N(z  
8F's9c,  
public Utility() jpTk@  
{ |zd5P  
 3SPXJa\i  
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} m| 7v76(  
>B*
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//线程睡眠 9U=6l]Np  
public static void sleep(int nSecond) K\s<<dRa  
{ BW`;QF<  
try{ +ef>ek  
Thread.sleep(nSecond); 9RkNRB)8  
} Ae"|a_>fMI  
catch(Exception e) 1rLxF{,  
{ o=xMaA  
e.printStackTrace (); a$bE2'cb  
} 8LXK3D}?3  
} Z5EII[=$o  
t%f>*}*P*  
//日志 JLjs`oqh  
public static void log(String sMsg) @,]W  
{ =wD&hDn4  
System.err.println(sMsg); \$F#bIjC  
} r)Ml-r=  
4%JJ}{Ff  
5l%g3F  
public static void log(int sMsg) 40dwp*/!  
{ o&$lik  
System.err.println(sMsg); s|TO9N)pO  
} >*n4j:  
} U9awN&1([  
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/* t"e%'dFv  
**TestMethod.java 6
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*/ LZE9]Gd  
package NetFox; _?$w8 S%  
R
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8+32hg@^F  
public class TestMethod { R9QW%!:,\2  
A6   
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public TestMethod() uX&h~qE/  
{ ///xx/weblogic60b2_win.exe 7|
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try{ P:1eWP  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); -@B6$XWL  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); }h8U.k?v  
SiteFileFetch fileFetch = new SiteFileFetch(bean); R"\(a  
fileFetch.start(); X\*H7;k,  
} ,_=LV  
catch(Exception e){e.printStackTrace ();} bBGg4{  
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^$RpP+d  
} nB5^  
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public static void main(String[] args) 1CV?  
{ tq=M 9c  
new TestMethod(); ?g0dr?H  
} C]ax}P>BQ  
} Hd gABIuX  
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