http断点续传简单实现（java)

/* bkRLC_/d  
**SiteFileFetch.java +20G>y=+  
*/ QemyCCP+  
package NetFox; j*d yp  
import java.io.*; :{{F *FM;  
import java.net.*; 97Lte5c6r  
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public class SiteFileFetch extends Thread { 5CuuG<0  
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SiteInfoBean siteInfoBean = null; //文件信息Bean =NpYFKmMhV  
long[] nStartPos; //开始位置 FW.7'7G@n  
long[] nEndPos; //结束位置 z Eq GD2"  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 57aXQ8u{  
long nFileLength; //文件长度 K)6rY(x >  
boolean bFirst = true; //是否第一次取文件 :X"?kK0V  
boolean bStop = false; //停止标志 v0ujdp,B  
File tmpFile; //文件下载的临时信息  vx\r!]  
DataOutputStream output; //输出到文件的输出流 ih)zG  
$Y;U[_l#  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） v/@^Q1G/:  
public SiteFileFetch(SiteInfoBean bean) throws IOException y>:N{|  
{ 1}S S+>`  
siteInfoBean = bean; rUwZMli  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); bw(a6qKK  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 'QJ:`)z  
if(tmpFile.exists ()) 90Pl$#cb2  
{ dMP
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bFirst = false; c>,KZ!  
read_nPos(); 9 *xR6  
} H-WJp<_  
else !]42^?GH  
{ &\#sI9  
nStartPos = new long[bean.getNSplitter()]; 1Rq,
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nEndPos = new long[bean.getNSplitter()]; B|Du@^$  
} fJ5
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} 
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public void run() )}g(b=  
{ *RDn0d[  
//获得文件长度 2SD`OABf#  
//分割文件 Ut*`:]la  
//实例FileSplitterFetch tankR9(o  
//启动FileSplitterFetch线程 [O$Wa:< 0x  
//等待子线程返回 VdPtPq1  
try{ ?OId\'q  
if(bFirst) \?w2a$?6w  
{ !6n_}I-W  
nFileLength = getFileSize(); l#m#c6;=  
if(nFileLength == -1) vV6<^W:9F  
{ Sw:7pByjI  
System.err.println("File Length is not known!"); &[_g6OL  
} Jk&3%^P{m  
else if(nFileLength == -2) neB\q[
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{ 6q*9[<8  
System.err.println("File is not access!"); ;i8g41qjF  
} . kQkC:~9  
else M*y)6H k~  
{ ^({})T0wu  
for(int i=0;i<nStartPos.length;i++) %
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{ 3e #p@sB  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); +:8fC$vVfC  
} -mAUo;O  
for(int i=0;i<nEndPos.length-1;i++) Q8C_9r/:N>  
{ WM Fb4SUR  
nEndPos = nStartPos[i+1]; C`K?7v3$m  
} nv GF2(;l  
nEndPos[nEndPos.length-1] = nFileLength; 4<9=5
q]  
} BYpG  
} 
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} bQ  
//启动子线程 5BWH-2HsB  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; >5_2_Y$"  
for(int i=0;i<nStartPos.length;i++) "/)#O
~  
{ 
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fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 2!0c4a^z  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),  ;ZH3{  
nStartPos,nEndPos,i); yaD~1"GA'O  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ,C K{F  
fileSplitterFetch.start(); Ed"h16j?z  
} e63uLWDT  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 4h~iPn'Wl  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); +$u$<z3Q  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", g@rb  
nEndPos = " + nFileLength); VkvB<3  
// fileSplitterFetch[nPos.length-1].start(); E4xj?m^(y=  
|P[w==AAf  
4F)-"ck  
//等待子线程结束 .)RzT9sg  
//int count = 0; vo`2\R.  
//是否结束while循环 05z,b]>l  
boolean breakWhile = false; kr+D,h01  
6tB+JF  
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while(!bStop) Ci?Ss+|  
{ t|a2;aq_  
write_nPos(); 8u"!dq  
Utility.sleep(500); Vc_'hz]Z  
breakWhile = true; T~--92[  
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for(int i=0;i<nStartPos.length;i++) {K <iih  
{ jB`,u|FG  
if(!fileSplitterFetch.bDownOver) `rgn<I"  
{ RzBF~2 >i  
breakWhile = false; _XG/Pp)  
break; XDsx3Ws  
} esHg'8?U  
} U@g4w!$r  
if(breakWhile) )+l\w3^6  
break; nKS7Q1+  
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//count++; lH#u  
//if(count>4) |L-]fjBbF  
// siteStop(); K17j$o^6KK  
} h^?\xm|  
{ WIJC',Y  
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System.err.println("文件下载结束！"); UADFnwR[R  
} IT(lF
 
catch(Exception e){e.printStackTrace ();} Rd2qe /  
} #,,d>e  
[ad@*KFxy3  
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//获得文件长度 I`p+Qt  
public long getFileSize() C3eR)Yh  
{ Inn@2$m~  
int nFileLength = -1; txW{7+,  
try{ Q?e*4ba  
URL url = new URL(siteInfoBean.getSSiteURL()); QOjqQfmM;  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); qLw{?sH}J/  
httpConnection.setRequestProperty("User-Agent","NetFox"); #i@;J]x(  
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int responseCode=httpConnection.getResponseCode(); ?,p;O  
if(responseCode>=400) +,2:g}5  
{ plUZ"Tr  
processErrorCode(responseCode); RMK"o?  
return -2; //-2 represent access is error eb.O#Y  
} 3x5JFM  
[baiH|5>  
!+1<E*NQ S  
String sHeader; uZc`jNc\  
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#z&&M"*a|  
for(int i=1;;i++) '>&^zgr  
{ } ~h3c
|  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); M*z~gOZ  
//Utility.log(in.readLine()); U@gn;@\  
sHeader=httpConnection.getHeaderFieldKey(i); d\p,2  
if(sHeader!=null) #N#
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{ FuVnk~g
q  
if(sHeader.equals("Content-Length")) .$Ik`[+Z  
{ (&}i`}v_  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ,a gc  
break; qDv93  
} 9F4Dm*_<  
} <\Eh1[F  
else 'ixw
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break; {XNREjhm  
} )f}YW/'  
} R<[qGt|L  
catch(IOException e){e.printStackTrace ();} :A1{d?B  
catch(Exception e){e.printStackTrace ();} Qy.w=80kf  
"5-^l.CKH  
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Utility.log(nFileLength); N F2/B#q  
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return nFileLength; 1y-y6q  
} /4c\K-Z;  
 Jd%H2`  
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//保存下载信息（文件指针位置） f#?fxUH~  
private void write_nPos() h!&prY
x  
{ 94+KdHAo^M  
try{ wT `a3Ymm  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Q7R~{5r>W  
output.writeInt(nStartPos.length); ZT,B(#m  
for(int i=0;i<nStartPos.length;i++) T?
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{ j:k[90  
// output.writeLong(nPos);  '`eO\huf  
output.writeLong(fileSplitterFetch.nStartPos); KMU4n-s"o  
output.writeLong(fileSplitterFetch.nEndPos); I2 j}Am  
} 4G$|Rx[{,  
output.close(); l7W 6qNB  
} <1FC%f/  
catch(IOException e){e.printStackTrace ();} E0u~i59Z  
catch(Exception e){e.printStackTrace ();} D[^m{ 9_  
} 5!l0zLQPo  
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//读取保存的下载信息（文件指针位置） LUuZ9$t0J"  
private void read_nPos() J13>i7]L%  
{ hJDi7P  
try{ :Qumb  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); >iD )eB  
int nCount = input.readInt(); pV20oSJNt  
nStartPos = new long[nCount]; T'4z=Z]w  
nEndPos = new long[nCount]; zY,r9<I8_x  
for(int i=0;i<nStartPos.length;i++) )6+eNsxMlC  
{ _C(m<n  
nStartPos = input.readLong(); c}y [[EX  
nEndPos = input.readLong(); !X"K=zt"  
} <(-3_s6-  
input.close(); !OA]s%u  
} Q.]}]QE   
catch(IOException e){e.printStackTrace ();} c8L~S/t  
catch(Exception e){e.printStackTrace ();} %7"X(Ts7B  
} cJ1#ge%4  
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private void processErrorCode(int nErrorCode) b
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{ D+]a.& {p  
System.err.println("Error Code : " + nErrorCode); cgm81+[%r  
}
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//停止文件下载 Au4yBm u  
public void siteStop() r41\r
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{ pcT:]d[1)  
bStop = true; `t_W2y
  
for(int i=0;i<nStartPos.length;i++) ,!dh2xNH
^  
fileSplitterFetch.splitterStop(); j:E<p_T  
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} YN`H BFH  
} A-4h  
//负责部分文件的抓取 J.ck~;3  
**FileSplitterFetch.java _Y
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*/ ^@qvl
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package NetFox; Y}uCP1v  
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import java.io.*; 7b<je=G6PA  
import java.net.*; ai nG6Y<O`  
=|I>G?g-  
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public class FileSplitterFetch extends Thread { \>CYC|  
@6mBqcE'?  
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String sURL; //File URL xZ4~Oo@@_'  
long nStartPos; //File Snippet Start Position Z00+!Tnd  
long nEndPos; //File Snippet End Position P?t"jKp'  
int nThreadID; //Thread's ID qIY~dQ|  
boolean bDownOver = false; //Downing is over =!`j7#:  
boolean bStop = false; //Stop identical h\nI!{A0  
FileAccessI fileAccessI = null; //File Access interface NGOqy+Ty{f  
\hhmVt@@  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException EI:w aIr  
{
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this.sURL = sURL; mml<
9fbH  
this.nStartPos = nStart; 6(G?MW.  
this.nEndPos = nEnd; Gi "941zVl  
nThreadID = id; <L`"!~Q  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 7.Z@Wr?  
} B<~ NS)w  
(;
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public void run() n84GZ5O>7  
{ |fSe>uVZ  
while(nStartPos < nEndPos && !bStop) U7I qST  
{ x\J#]d.  
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try{ E;1Jh(58)b  
URL url = new URL(sURL); I_xXDr  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 2n `S5(
V  
httpConnection.setRequestProperty("User-Agent","NetFox"); =k/IaFg 6w  
String sProperty = "bytes="+nStartPos+"-";  b^p"|L  
httpConnection.setRequestProperty("RANGE",sProperty); fH)YFn/  
Utility.log(sProperty); D<Zp!J1o  
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InputStream input = httpConnection.getInputStream(); 7{I h_.#  
//logResponseHead(httpConnection); 1[jb)j1  
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byte[] b = new byte[1024]; 7c~u=U"  
int nRead; +reor@h  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ~i21%$  
{ v@wb"jdFi$  
nStartPos += fileAccessI.write(b,0,nRead); [+OnV&  
//if(nThreadID == 1) D<V~f B  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); =e8bNg  
} 2'5]~  
vq!_^F<  
7f~Sf  
Utility.log("Thread " + nThreadID + " is over!"); _L@2_
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bDownOver = true; ,2j.<g&
  
//nPos = fileAccessI.write (b,0,nRead); 5vw{b
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} ^|TG$`M(w
 
catch(Exception e){e.printStackTrace ();} xCYE B}o9r  
} Gkp<o  
} dlG=Vq&Y  
jS]><rm  
=IUUeFv +r  
//打印回应的头信息 bzvh%RsW  
public void logResponseHead(HttpURLConnection con) 8 O67  
{ :_@JA0n  
for(int i=1;;i++) UQ[B?jc  
{ fm^@i;D  
String header=con.getHeaderFieldKey(i); z8[yt282  
if(header!=null) 2KQoy;  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); cZ<A0  
Utility.log(header+" : "+con.getHeaderField(header)); KX}Rr
7a  
else RKPD4e>%  
break; |U_]vMq  
} IN,(yaC  
} v$=QA:!U  
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,9P:Draxs`  
public void splitterStop() IXb}AxBf  
{ =&},;VOh  
bStop = true; \4AM*lZ  
} ?_ dIIQ  
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} yB3;  
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/* bcAvM;  
**FileAccess.java l27\diKPJ  
*//文件访问(定位，写) TuW/N L|  
package NetFox; 6:]*c[7  
import java.io.*; 06Gt&_Q  
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public class FileAccessI implements Serializable{ MCT'Nw@A  
qVdwfT{1J  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 B}eA\O4}I  
RandomAccessFile oSavedFile; UK{irU|\  
long nPos; F {B\kq8  
>/#KI~}'N  
& u!\<\  
public FileAccessI() throws IOException %J8|zKT5t  
{ @?[1_g_'P  
this("",0); !=y]Sv~h  
} rLU/W<F8  
A"aV'~>  
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public FileAccessI(String sName,long nPos) throws IOException 2QNNp:`6  
{ i@][rdhT  
oSavedFile = new RandomAccessFile(sName,"rw"); -kS~xVS|  
this.nPos = nPos; 9m-)Xdoy  
oSavedFile.seek(nPos); 8v7
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} 93<:RV  
dVQ-
k  
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public synchronized int write(byte[] b,int nStart,int nLen) fl;s9:<  
{ jA(>sz  
int n = -1; zSE<"(a  
try{ :=9]c17=  
oSavedFile.write(b,nStart,nLen); @m?QR(LJ  
n = nLen; !I\!;b  
} &h~Xq^  
catch(IOException e) 4HAp{
a1  
{ ||zb6|7I4  
e.printStackTrace (); :iiw3#]  
} >I<r)w]  
j
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return n; 0A:n0[V:]  
} fGv#s X  
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} 8_&CT :u>  
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/*
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**SiteInfoBean.java |ea~'N1  
*/ }dxDtqb  
package NetFox; Bk}><H  
{}o>{&X  
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public class SiteInfoBean { Fxc)}i`   
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private String sSiteURL; //Site's URL hfcIvs/!  
private String sFilePath; //Saved File's Path lc6iKFyG  
private String sFileName; //Saved File's Name h8G5GRD  
private int nSplitter; //Count of Splited Downloading File /j"sS2$U  
"C?5f]T  
F/1#l@qN  
public SiteInfoBean() + <c^=&7Lq  
{//nSplitter的缺省值为5 Eh|.  
//default value of nSplitter is 5 f(D_FTTO  
this("","","",5); +Ug/rtK4  
} Kd3?I5t  
0Y
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ~dHM4lGY  
{ |B
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sSiteURL= sURL; WS2osBc  
sFilePath = sPath; ^Cv^yTj;&  
sFileName = sName; q@hp.(V  
this.nSplitter = nSpiltter; >O/D!j|  
!'=15&5@  
}<jb vCeK  
} mfny4R
1_  
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public String getSSiteURL() ^O^:$nXhYy  
{ h5kPn~  
return sSiteURL; /$"[k2 N  
} rs=q! P"u[  
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public void setSSiteURL(String value) YYg)  
{ ~Cc.cce5  
sSiteURL = value; % p?brc  
} r$wZt  
+]:2\TTGI  
*FR$vL
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public String getSFilePath() iv(5&'[p  
{ "tS'b+SJ-S  
return sFilePath; ZiFooA  
} JM.XH7k  
'rb'7=z5  
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public void setSFilePath(String value) (IbW;bV  
{ [O ",  
sFilePath = value; vQ@2FZzu>  
} iO1nwl !#  
w(nHD*nm  
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public String getSFileName() rAdacnZV  
{ Gi^Ha=?J%
 
return sFileName; .wrL3z_  
} $\a5&1rl  
T:asm1BC[  
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public void setSFileName(String value)  1;eX&  
{ /"qcl7F  
sFileName = value; V_U'P>_I  
} M~6@20$oW  
O$!*%TL  
!wLg67X$ -  
public int getNSplitter() k /EDc533d  
{ %bb~Y"  
return nSplitter; ~:sE:9$z  
} o[6y+<'o  
;/AG@$)  
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public void setNSplitter(int nCount) J?:[$C5  
{ |f2A89  
nSplitter = nCount; YJ7V`Np  
} !$XHQLqF2  
} ZC^C  
}UyQ#U  
3mt%!}S  
/* 6\dX
 
**Utility.java Md;/nJO~{  
*/ V
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package NetFox; nw'-`*'rj  
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public class Utility { #$'"cfRxc  
j;P+_Hfe/E  
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public Utility() Sj 3oV  
{ i&+w _hD  
>N`6;gn*l  
_94s(~g:  
} IvBGpT"(I  
*8g<R  
//线程睡眠 ]Nk!4"  
public static void sleep(int nSecond) X.|Ygx  
{ v1[_}N9f>H  
try{ 0^!Gib  
Thread.sleep(nSecond); hY\{|  
} p_terD:  
catch(Exception e) dXu{p  
{ CVKnTEs  
e.printStackTrace (); E%k7wM {  
} ddpl Pzm#  
} FbSa~uN  
*crw^e  
//日志 0~E 6QhV:  
public static void log(String sMsg) DR+,Y2!_GT  
{ ]YD(`42x  
System.err.println(sMsg); Y\t_&px  
} I ,FqN}  
M?6;|-HH  
x(r+P9f\<  
public static void log(int sMsg) cz.3|Lby  
{ 5h_5Z
~  
System.err.println(sMsg); 6nw&$I  
} ,a(O`##Bn  
} jqoPLbxT
 
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[Z}B"  
/* T[Q"}&bB  
**TestMethod.java Gi$gtLtNh  
*/ bejGfc  
package NetFox; d?Y-;-|8Qh  
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public class TestMethod { c;V D}UD'  
P1d,8~;  
03E3cp"  
public TestMethod() m4**>!I  
{ ///xx/weblogic60b2_win.exe O2#S: ~h  
try{ :I
/  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); W%8+t)
 
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); kO3`54  
SiteFileFetch fileFetch = new SiteFileFetch(bean); H@!#;w  
fileFetch.start(); D9,! %7i  
} &:vscOl  
catch(Exception e){e.printStackTrace ();} ^87
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} V/H@vKN2  
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T Oy7?;|=  
public static void main(String[] args) 8W{~wg`  
{ G' Hh{_:  
new TestMethod(); u6_jn
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} fPE?hG<x  
} q) _r3   
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