http断点续传简单实现（java)

/* d2L&Z_
}  
**SiteFileFetch.java uCB=u[]y4  
*/ ;722\y(Y  
package NetFox; z\4.Gm-  
import java.io.*; `uTmw^pZX  
import java.net.*; >+T)#.wo&  
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public class SiteFileFetch extends Thread { b|(:[nB  
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SiteInfoBean siteInfoBean = null; //文件信息Bean `kS
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long[] nStartPos; //开始位置 `XDl_E+>l  
long[] nEndPos; //结束位置 RT8 ?7xFc  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 G^@5H/)  
long nFileLength; //文件长度 9W);rL|5  
boolean bFirst = true; //是否第一次取文件 M D#jj3y  
boolean bStop = false; //停止标志 AQ^u  
File tmpFile; //文件下载的临时信息 + >!;i6|  
DataOutputStream output; //输出到文件的输出流 #4;wjcGWw  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） )QJUUn#  
public SiteFileFetch(SiteInfoBean bean) throws IOException (**oRwr%  
{ |k9 C/  
siteInfoBean = bean; B`sAk %  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ?gXp*>Kg[  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 1{.9uw"2S  
if(tmpFile.exists ()) pTuS*MYz  
{ QTnP'5y  
bFirst = false; ksm~<;td  
read_nPos(); ,`sv1xwd  
} UC$ppTCc?  
else yWf`rF{  
{ zKK9r~ M  
nStartPos = new long[bean.getNSplitter()]; b~cZS[S  
nEndPos = new long[bean.getNSplitter()]; l%=;  
} IAyp2  
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} ?&uu[y  
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public void run() lmhLM. 2  
{ 2 ? 4!K.  
//获得文件长度 \}G^\p6?M  
//分割文件 gI`m.EH}}N  
//实例FileSplitterFetch >.D4co>  
//启动FileSplitterFetch线程 u]G\H!WkQ  
//等待子线程返回 H%{+QwzZ[j  
try{ A?0Nm{O;3v  
if(bFirst) f,Ghb~y  
{ bN=P*hdf  
nFileLength = getFileSize(); -7|H}!DFT  
if(nFileLength == -1) $Z>'Jp  
{ o;RI*I  
System.err.println("File Length is not known!"); A<fG}q1#  
} 8l">cVo]T  
else if(nFileLength == -2) [.}oyz;}N  
{ TJ*T:?>e  
System.err.println("File is not access!"); \^1E4C\":  
} . 'yCw#f  
else $`'/+x"%  
{ ABYcH]m  
for(int i=0;i<nStartPos.length;i++) *n"{J(Jt`  
{ d0 /#nz  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ll?X@S  
} m)D|l1AtF  
for(int i=0;i<nEndPos.length-1;i++) |+"(L#wk  
{ ]{>,rK[So  
nEndPos = nStartPos[i+1]; %xt^698&X  
} V^~:F  
nEndPos[nEndPos.length-1] = nFileLength; W!(LF7_!  
} "^iYLQOC  
} &Hnz8Or!  
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uvS)
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//启动子线程 E<*xx#p  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; wUM0M?_p[  
for(int i=0;i<nStartPos.length;i++) ,"0:3+(8;  
{ Q=dy<kg']  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), >`D:-huNeE  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 7IM@i>p%  
nStartPos,nEndPos,i); yaV|AB$v  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); {(?4!rh  
fileSplitterFetch.start(); pmYHUj #  
} !Xw5<J3L-  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), +qdEq_m  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 3T0"" !Q  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", f|oh.z_R  
nEndPos = " + nFileLength); t.C5+^+%  
// fileSplitterFetch[nPos.length-1].start(); < FAheE+  
{+b7sA3
 
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//等待子线程结束 Y`wSv NU  
//int count = 0; bi;1s'Y<D  
//是否结束while循环 g< .qUBPKX  
boolean breakWhile = false; Rbv;?'O$L  
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while(!bStop) Eu04e N  
{ see
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write_nPos(); ZqO^f*F>h  
Utility.sleep(500); 18:%~>.!  
breakWhile = true; 0+b1vhQ  
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for(int i=0;i<nStartPos.length;i++) )@bQu~Y  
{ #:%/(j  
if(!fileSplitterFetch.bDownOver) "U"Z 3*  
{ |#N&akC  
breakWhile = false; \Y}8S/]  
break; mpJ#:}n  
} Wo=jskBrQ  
} `Ryp% Bn  
if(breakWhile) <1M-Ro?5k  
break; ;t`&n['N>  
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//count++; r",GC]  
//if(count>4) sCHJ&>m5-  
// siteStop(); Q&bM\;Ml  
} ]e@Oiq  
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System.err.println("文件下载结束！"); R*r#E{!V;  
} c~ V*:$F  
catch(Exception e){e.printStackTrace ();} 5l*&>C[(i  
} G,w(d@  
VY\&8n}e(  
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//获得文件长度 R{T$[$6S  
public long getFileSize() $iz|\m  
{ 4+ Z]3oIRE  
int nFileLength = -1; 5/Uy{Xt  
try{ {Y9q[D'g.  
URL url = new URL(siteInfoBean.getSSiteURL()); '2^Q1{ :\  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); H<N,%G  
httpConnection.setRequestProperty("User-Agent","NetFox"); i K? w6  
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int responseCode=httpConnection.getResponseCode(); pz>>)c`  
if(responseCode>=400) 4HA<P6L  
{ A^<iL  
processErrorCode(responseCode); PwLZkr@4^  
return -2; //-2 represent access is error -3Vx76Y  
} 4{`{WI{  
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String sHeader; V "h +L7T  
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for(int i=1;;i++) [ibu/W$  
{ ~$?ZK]YOrx  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ea')$gR  
//Utility.log(in.readLine()); C3YT1tK  
sHeader=httpConnection.getHeaderFieldKey(i); w`zTR0`  
if(sHeader!=null) ~Jz6O U*z  
{ ixD)VcD-f  
if(sHeader.equals("Content-Length")) S^\Vgi(  
{ /t"3!Z?BOv  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); _aT5jR=  
break; E~oOKQ5W  
} pIX`MlBdF  
} )+2hl  
else Jg|XH L)  
break; emN*l]N  
} }9fTF:P  
} dlTt_.  
catch(IOException e){e.printStackTrace ();} )hfpwdQ  
catch(Exception e){e.printStackTrace ();} oM
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Utility.log(nFileLength); `+Q%oj#FF  
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return nFileLength; ?<'}r7D   
} #4 pB

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hQDXlFHT  
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//保存下载信息（文件指针位置） OpYY{f  
private void write_nPos() I9hK}
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{ kpN)zxfk  
try{ |8tilOqI  
output = new DataOutputStream(new FileOutputStream(tmpFile)); `RL"AH:+  
output.writeInt(nStartPos.length); hx]?&zT@  
for(int i=0;i<nStartPos.length;i++) N[ Og43Y  
{ A2jUmK.&  
// output.writeLong(nPos); q5)O%l!  
output.writeLong(fileSplitterFetch.nStartPos); fmDCPkj  
output.writeLong(fileSplitterFetch.nEndPos); DlMW(4(  
} 81 sG  
output.close(); v,>Dbxn  
} @t_=Yl2
;  
catch(IOException e){e.printStackTrace ();} W v+?
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catch(Exception e){e.printStackTrace ();} A{D];pE`  
} Fy-t T]Q9  
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//读取保存的下载信息（文件指针位置） P me^l%M  
private void read_nPos() |4 0`B% Z  
{ ,wAF:7'  
try{ :^B1~p(?sK  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); O[JL+g4  
int nCount = input.readInt(); 6G""I]uT  
nStartPos = new long[nCount]; o]I\6,T/|  
nEndPos = new long[nCount]; %/#NK1&M  
for(int i=0;i<nStartPos.length;i++) {[?(9u7R  
{ 1NA.nw.  
nStartPos = input.readLong(); ^sLdAC  
nEndPos = input.readLong(); Cd}<a?m,  
} 68WO~*  
input.close(); CdjI`  
} lchPpm9  
catch(IOException e){e.printStackTrace ();} sN01rtB(UT  
catch(Exception e){e.printStackTrace ();} 6zuTQ^pz  
} t=W}SH  
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private void processErrorCode(int nErrorCode) hy"\RW  
{ }*pi<s  
System.err.println("Error Code : " + nErrorCode); <k'h:KB?`  
} @O^6&\s>  
:(*V?WI  
]Ntmy;Q  
//停止文件下载 jkF
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public void siteStop() =R$u[~Xl2X  
{ @>Km_Ax  
bStop = true; -Cc^d!::  
for(int i=0;i<nStartPos.length;i++) "n5N[1bk  
fileSplitterFetch.splitterStop(); Ig0VW)@  
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} EaY?aAuS:  
} ra gXn  
//负责部分文件的抓取 O`t&ldU  
**FileSplitterFetch.java ]Wlco
 
*/ p}pjfG  
package NetFox; eF-."1  
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import java.io.*; !Pfr,a  
import java.net.*; wIaony  
j[J-f@F \Y  
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public class FileSplitterFetch extends Thread { wc^tgE  
">,|V-H  
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String sURL; //File URL +.b,AqJ/  
long nStartPos; //File Snippet Start Position b&N'C9/8  
long nEndPos; //File Snippet End Position 9x9T<cx  
int nThreadID; //Thread's ID u(F_oZ~  
boolean bDownOver = false; //Downing is over 9ZsVy
 
boolean bStop = false; //Stop identical w4{<n/"  
FileAccessI fileAccessI = null; //File Access interface U,{eHe ?>T  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException \aUC(K~o\;  
{ V1`o%;j  
this.sURL = sURL; RmeD$>7  
this.nStartPos = nStart; SBk4_J/_  
this.nEndPos = nEnd; k:#!zK}  
nThreadID = id; [ =9T*Sp  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 #:U%mHT(_  
} )e=D(qd  
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public void run() $$;M^WV^?.  
{ s.QwSbw-g  
while(nStartPos < nEndPos && !bStop) d_E/8R_$L  
{ rCbDu&k]  
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try{ 3-qr)h  
URL url = new URL(sURL); b)5uf'?-  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 4ber!rJM  
httpConnection.setRequestProperty("User-Agent","NetFox"); G+"t/?/  
String sProperty = "bytes="+nStartPos+"-"; /1V xc 6  
httpConnection.setRequestProperty("RANGE",sProperty); )9'K($  
Utility.log(sProperty); 7<#U(,YEA  
;oKZ!ND  

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InputStream input = httpConnection.getInputStream(); p\tm:QWD;  
//logResponseHead(httpConnection); qHplJ "  
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byte[] b = new byte[1024]; N06OvU2>xU  
int nRead; %G/hD  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ^?7-r6  
{ +-U- D?-  
nStartPos += fileAccessI.write(b,0,nRead);  Rn(ec  
//if(nThreadID == 1) < #}5IQ5`Z  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ~IfJwBn-i  
} tGh~!|P  
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Utility.log("Thread " + nThreadID + " is over!"); bz2ztH9 n  
bDownOver = true; i$:*Pb3mV  
//nPos = fileAccessI.write (b,0,nRead); v6M6>&RR|  
} Vl/+;6_  
catch(Exception e){e.printStackTrace ();} wc NOLUl  
} HJLG=mU  
} G )trG9 .a  
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//打印回应的头信息 mAj?>;R2$2  
public void logResponseHead(HttpURLConnection con) :bu/^mW[  
{ V6&!9b  
for(int i=1;;i++) Yz/md1T$  
{ +`7i'ff  
String header=con.getHeaderFieldKey(i); %S@ZXf~:  
if(header!=null) \K{0L  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 9N%We|L,c  
Utility.log(header+" : "+con.getHeaderField(header)); n.`($yR_  
else 6xe*E[#k\  
break; 7$vYo _  
} \Fbv
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} :0j?oY~e  
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public void splitterStop() jk; clwyz/  
{ +,TRfP Fb  
bStop = true; 85|OGtt  
} U0 Yll4E  
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} 1MP~dRZ$  
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/* !*
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**FileAccess.java W#4 7h7M  
*//文件访问(定位，写) @;zl  
package NetFox; w;[NH/A^a  
import java.io.*; _(W+S`7Z  
@Q ]
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public class FileAccessI implements Serializable{ *v jmy/3  
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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 B4c]}r+  
RandomAccessFile oSavedFile; |"X*@s\'  
long nPos; xaq-.IQAM$  
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public FileAccessI() throws IOException AW%#O\N  
{ ?>D+ge  
this("",0); (Du@ S  
} Zw 26  
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public FileAccessI(String sName,long nPos) throws IOException Xk~D$~4<  
{ ~9,,~db  
oSavedFile = new RandomAccessFile(sName,"rw"); =V,mtT  
this.nPos = nPos; DbBcQ%  
oSavedFile.seek(nPos); ~9a<0Mc?  
} I+%[d^,  
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[64:4/<}  
public synchronized int write(byte[] b,int nStart,int nLen) Sxt"B  
{ 7{e 4c  
int n = -1; r_)' Ps  
try{ P%V'4pc  
oSavedFile.write(b,nStart,nLen); k_L7 kvpt  
n = nLen; ~RW+GTe  
} |B?m,U$A!  
catch(IOException e) X:f UI4  
{ h0*!;Z7  
e.printStackTrace (); u:6Ic)7'  
} 59LZv-l  
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return n; 9tU]`f  
} .KB^3pOpx  
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} `&r+F/Ap2  
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/* !fV+z%:  
**SiteInfoBean.java Avge eJi  
*/ #5Qpu  
package NetFox; |PvPAPy)uu  
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public class SiteInfoBean { *<$*"p  
+xh`Q=A  
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private String sSiteURL; //Site's URL =m]v8`g  
private String sFilePath; //Saved File's Path !j
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private String sFileName; //Saved File's Name ,Q3T Tno ,  
private int nSplitter; //Count of Splited Downloading File m<<+  
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public SiteInfoBean() ~dyTVJ$  
{//nSplitter的缺省值为5 bbDZ#DK"  
//default value of nSplitter is 5 8 `v-<J  
this("","","",5); n2"a{Ofhlf  
} gldAP:  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) HDz5&7* .  
{ aG-vtld  
sSiteURL= sURL; $f$SNx)),  
sFilePath = sPath; f%A;`4`q  
sFileName = sName; #>a\>iKQ2q  
this.nSplitter = nSpiltter; ]vB$~3||  
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} :p1u(hflS  
7zl5yKN  
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public String getSSiteURL() ^Y?k0z  
{ G~]Uk*M q  
return sSiteURL; B5,N7z34F  
} =bAx,,D#  
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public void setSSiteURL(String value) dUD[e,?  
{ WSPI|#Xr%  
sSiteURL = value;
"syI#U{  
} n.}ZkG0`  
7RQR)DG  
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public String getSFilePath() &.F4b~A7  
{ SjK  
return sFilePath; 1;* cq  
} <q)#  
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public void setSFilePath(String value) j\ZXG=j  
{ b3P+H r  
sFilePath = value; Yz9owe8}[  
} !@5 9)  
[XN={  
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public String getSFileName() qfX6TV5J}!  
{ 44J]I\+  
return sFileName; Mg+2. 8%  
} A_rGt?i  
i[i4h"$0  
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public void setSFileName(String value) 6u?>M9  
{ E[OJ+ ;c  
sFileName = value; 1Te%F+7  
} !OZy7  
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public int getNSplitter() #j;^\rSv-  
{ &Hrj3E  
return nSplitter; eB2a
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} )J=!L\  
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public void setNSplitter(int nCount) oE6tauQn  
{ S*pGMuui  
nSplitter = nCount; Xa[.3=bV?  
} y4yhF8E>;U  
} ^"E^zHM(  
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/* )w em|:H  
**Utility.java rDtY[  
*/ =&6eM2>P  
package NetFox; JhYe6y[q  
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public class Utility { b\f O8{k  
#x@$lc=k3  
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public Utility() ]dVGUG8  
{ 4>YR{  
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} 0J*??g-n  
yHYsZ,GE  
//线程睡眠 i%iL[id:w  
public static void sleep(int nSecond) xH4m|  
{ q~Hn-5H4Q  
try{ _{ue8kGt  
Thread.sleep(nSecond); ,O5NLg-  
} E*&vy  
catch(Exception e) Ha#=(9.  
{ d2FswF$C  
e.printStackTrace (); -12UN(&&Z  
}  ,i NXK  
} @)F)S7  
eSn+B;  
//日志 Vsr.=Nd=  
public static void log(String sMsg) 1NFsb-<u  
{ J6"9v;V  
System.err.println(sMsg); -]Bq|qTH[(  
} >tS'Q`R
 
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public static void log(int sMsg) iO{h
A  
{ 'ycJMYP8  
System.err.println(sMsg); Ep_HcX`  
} OG~gFZr)6  
} p>,|50|  
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@)+AaC#-  
/* gk4;>}  
**TestMethod.java Z3e| UAif  
*/ 8LJ8 }%*  
package NetFox; &,vcJ{.  
,oe <  
u]wZQl#-  
public class TestMethod { .8g)av+  
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8$cLG*=h4  
public TestMethod() CZe ]kXNv  
{ ///xx/weblogic60b2_win.exe .~db4d]  
try{ KM0ru  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); L<S9  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); qArM|\l1  
SiteFileFetch fileFetch = new SiteFileFetch(bean); *U-4Sy  
fileFetch.start(); ~Gp[_ %K  
} .<?GS{6 N  
catch(Exception e){e.printStackTrace ();} yF:1( 4  
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} Rh2+=N<X  
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public static void main(String[] args) o 11jca|  
{ Xq4O@V  
new TestMethod(); iXkF1r]i  
} qbr$>xH  
} ^6
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