http断点续传简单实现（java)

/* UAT46  
**SiteFileFetch.java I?v)>||Q  
*/ XnQd(B`M  
package NetFox; ,9q=2V[GP  
import java.io.*; h'<}
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import java.net.*; F_!6C-z  
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public class SiteFileFetch extends Thread { $V~r*#$.  
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SiteInfoBean siteInfoBean = null; //文件信息Bean z12[vN  
long[] nStartPos; //开始位置 pr\yc  
long[] nEndPos; //结束位置 kL^
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FileSplitterFetch[] fileSplitterFetch; //子线程对象 )#MKOsOct  
long nFileLength; //文件长度 |2XEt\P  
boolean bFirst = true; //是否第一次取文件 Dn _D6H  
boolean bStop = false; //停止标志 UM7Ft"  
File tmpFile; //文件下载的临时信息 ics  
DataOutputStream output; //输出到文件的输出流 ]nN']?{7PW  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） p8
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public SiteFileFetch(SiteInfoBean bean) throws IOException FyYQ4ov0&o  
{ )1O *~%  
siteInfoBean = bean; __c:$7B/4U  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); |v8>22y  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 9u1)Kr=e  
if(tmpFile.exists ()) )_b#c+  
{ yw5MlZ4P=  
bFirst = false;
Mk= tS+  
read_nPos(); Hjli)*ev  
} M|FwYF^  
else T1;yw1/m5\  
{ P"_x/C(]@J  
nStartPos = new long[bean.getNSplitter()]; &by,uVb=|{  
nEndPos = new long[bean.getNSplitter()]; m^h"VH,   
} BnqAv xX  
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} SY["(vP%#  
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public void run() 6}IOUWLB@  
{ 8iD_md_[  
//获得文件长度 h$~ NPX  
//分割文件 %|Gi'-'|b$  
//实例FileSplitterFetch YWM$%  
//启动FileSplitterFetch线程 zY(*Xk  
//等待子线程返回 .txgb  
try{ j*Q/
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if(bFirst) y<k-d
br  
{ Gu~y/CE'  
nFileLength = getFileSize(); N2;T\xx,  
if(nFileLength == -1) |A7Yv  
{ :D-d`OyjG>  
System.err.println("File Length is not known!"); Ka2U@fK"  
} `8\pihww  
else if(nFileLength == -2) QY-P!JD  
{ >Fz_]z   
System.err.println("File is not access!"); b`E0tZcJ  
} gPe*M =iF  
else SS O$.rp  
{ k\Oy\z@  
for(int i=0;i<nStartPos.length;i++) ):&A\nb  
{ I'BoP  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 2j H`  
} Tx0/3^\>8A  
for(int i=0;i<nEndPos.length-1;i++) 17H_>a
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{ 1@E<5rp o  
nEndPos = nStartPos[i+1]; 1;SW%\M  
} *f.eyg#  
nEndPos[nEndPos.length-1] = nFileLength; !y'LKze+G  
} 0 '~Jr\4  
} 6=90 wu3  
?;+=bKw0  
sL~TV([6/  
//启动子线程 f`p`c*  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; FM0)/6I'x  
for(int i=0;i<nStartPos.length;i++) ZN~:^,PO/  
{ \sEq r)\k  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 3V?JX5X\  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 8)s}>:}  
nStartPos,nEndPos,i); `Xc~'zG  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); dZFf/BXU  
fileSplitterFetch.start(); ;+'x_'a  
} NTASrh  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 5D8V)i  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); @Hw#O33/'  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", =Bcwd7+  
nEndPos = " + nFileLength); {u{n b3/jl  
// fileSplitterFetch[nPos.length-1].start(); U$Z)v1&{  
\HF|&@}hU  
7m~.V[l
1  
//等待子线程结束 \XFF(  
//int count = 0; +)k%jIi!  
//是否结束while循环 =e=sK'NvD  
boolean breakWhile = false; 3.Z}2F]  
|k1(|)%G  
Azvj(j  
while(!bStop) : KhAf2A  
{ 9_)*b  
write_nPos(); ~~!iDF\  
Utility.sleep(500); @W[`^jfQ  
breakWhile = true; %ZF47P%6  
kG@~;*;l  
9dn~nnd'n  
for(int i=0;i<nStartPos.length;i++) Jz(wXp  
{ btoye \rl  
if(!fileSplitterFetch.bDownOver) JnQ5r>!>3  
{ _LU]5$\
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breakWhile = false; =&jLwy  
break; =Y Je\745  
} 0Mpc#:a%1  
} A:Pp;9wl  
if(breakWhile) {Z%4Pg  
break; }iZO0C  
2L Kpwz?  
L}NckL  
//count++; P>n}\"z4  
//if(count>4) 
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// siteStop(); FC[8kq>Hk  
} `1k0wT(  
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MWTzJGRT  
System.err.println("文件下载结束！"); = i9|lU"Va  
} (Qq;ySZ#  
catch(Exception e){e.printStackTrace ();} %ub\+~  
} f|Dq#(^\  
HjCcfOej  
{ZQ|Ydpk  
//获得文件长度 V|9<*  
public long getFileSize() D32~>J.F  
{ '*gY45yT`  
int nFileLength = -1; n=Qz7N(M  
try{ !o+[L  
URL url = new URL(siteInfoBean.getSSiteURL()); 6/
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); zr#n^?m  
httpConnection.setRequestProperty("User-Agent","NetFox"); 6?8x[l*5M  
7bJAOJ'_  
s[6y|{&ze  
int responseCode=httpConnection.getResponseCode(); v3>jXf  
if(responseCode>=400) $0+n0*fp  
{ $bSnbU<  
processErrorCode(responseCode); &(&5ao)5  
return -2; //-2 represent access is error 6WUP
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} L-SWs8  
 {}x{OP  
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String sHeader; "A?&`}%  
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for(int i=1;;i++) qcpAjjK  
{ a2Q_K2t  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 4FLL*LCNX  
//Utility.log(in.readLine()); c*R?eLt/  
sHeader=httpConnection.getHeaderFieldKey(i); 3>O=d>  
if(sHeader!=null) (.[HE ~ s?  
{ U&x)Q  
if(sHeader.equals("Content-Length")) ^q{=mf`  
{ KlOL5"3  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); sUl/9VKl  
break; wP-BaB$_  
} Y243mq-  
} L{)*evBL  
else ]rAaErB';  
break; N-C=O  
} lHl1Ny\?  
} J+IkTq
w  
catch(IOException e){e.printStackTrace ();} @ootKY`  
catch(Exception e){e.printStackTrace ();} ]&;M78^6  
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Utility.log(nFileLength); F,
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return nFileLength; jbrx)9Z+%  
} slPLc  
t^ax:6;"|  
 a@mMa {  
//保存下载信息（文件指针位置） %v)m&VUi%  
private void write_nPos() Fke_ms=I^  
{ vdS)
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try{ RxUABF8b  
output = new DataOutputStream(new FileOutputStream(tmpFile)); *.g@6IkAQ  
output.writeInt(nStartPos.length); %p wpRD@  
for(int i=0;i<nStartPos.length;i++) QVEGd"WvvO  
{ (}^Qo^Vr  
// output.writeLong(nPos); @-d0~.S  
output.writeLong(fileSplitterFetch.nStartPos); )$Tcip`  
output.writeLong(fileSplitterFetch.nEndPos); XH
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} (A<'{J#5,  
output.close(); (bT3 r_  
} iRwlK5(&  
catch(IOException e){e.printStackTrace ();} F@C^nX9  
catch(Exception e){e.printStackTrace ();} A]x'!qa@=  
} 4|yZA*Q^  
@20~R/vh  
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//读取保存的下载信息（文件指针位置） cwK+{*ZH/
 
private void read_nPos() ;`p!/9il  
{ %+Az X  
try{ %BV2 q  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); <Oyxzs  
int nCount = input.readInt(); :f9O3QA  
nStartPos = new long[nCount]; c+_F}2)  
nEndPos = new long[nCount]; '5:P,1tWU  
for(int i=0;i<nStartPos.length;i++) 6e%|.}U  
{ ]E8S`[Vn  
nStartPos = input.readLong(); yEvuTgDv  
nEndPos = input.readLong(); DnY7$']"|  
} PNn-@=%  
input.close(); 4R8W ot  
} +|SvJ  
catch(IOException e){e.printStackTrace ();} +0)zB;~7  
catch(Exception e){e.printStackTrace ();} F~qiNV  
} (";{@a %  
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private void processErrorCode(int nErrorCode) gJn_Z7MgJ  
{ 'J0Erk8(  
System.err.println("Error Code : " + nErrorCode); ,:G3Y )  
} kJy bA  
71$MhPvd<  
i*q!
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//停止文件下载 Vv]81y15Q;  
public void siteStop() q%^vx%aL\  
{ MZ/PXY  
bStop = true; `U~Y{f_!H  
for(int i=0;i<nStartPos.length;i++) tWo MUp  
fileSplitterFetch.splitterStop(); "q'9-lk  
 `LWZ!Q  
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} 1zz.`.R2U  
}
1!;}#m7v  
//负责部分文件的抓取 #"Wh$x%  
**FileSplitterFetch.java GNv5yWQ@  
*/ jNO8n)a&p  
package NetFox; C6"bGA  
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import java.io.*; WecJ^{g>r{  
import java.net.*; *C0gpEf9S  
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public class FileSplitterFetch extends Thread { 7+h*&f3>  
wn$:L9"YN  
4-YXXi}  
String sURL; //File URL c=-2c&=&  
long nStartPos; //File Snippet Start Position q|8p4X}/]  
long nEndPos; //File Snippet End Position "eH~/6A  
int nThreadID; //Thread's ID I8<s4q   
boolean bDownOver = false; //Downing is over .QhH!#Y2D  
boolean bStop = false; //Stop identical !iOuIYjV  
FileAccessI fileAccessI = null; //File Access interface V r0-/T  
D(GAC!|/]  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException j&S8x|5  
{ 4't@i1Ll(  
this.sURL = sURL; yL&_>cV  
this.nStartPos = nStart; u D.E>.B  
this.nEndPos = nEnd; ;-G!jWt6Zi  
nThreadID = id; qwb`8o  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 -CTsB)=\,  
} >Kd(.r[Er  
(5"BKu1t  
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public void run() $j~oB:3n7  
{ _n3Jf<Y  
while(nStartPos < nEndPos && !bStop) Oc]&1>M  
{ l7]$Wc[  
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try{ VH{SE7  
URL url = new URL(sURL); y %k`  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); '(/ZJ88JP  
httpConnection.setRequestProperty("User-Agent","NetFox"); {d;eZt `  
String sProperty = "bytes="+nStartPos+"-"; ,]N!I%SI  
httpConnection.setRequestProperty("RANGE",sProperty); SZ
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Utility.log(sProperty); =f)S=0UF  
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InputStream input = httpConnection.getInputStream(); X-Sso9/q.  
//logResponseHead(httpConnection); EO|r  
))n7.pB9/  
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byte[] b = new byte[1024]; mne^PSI:  
int nRead; ?-FSDNQ  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) u+]v.Mt  
{ |wf:|%  
nStartPos += fileAccessI.write(b,0,nRead); zS:89y<  
//if(nThreadID == 1) lPS
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// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); t9&z|?Vz  
} E(T6s^8  
xNNoB/DR  
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Utility.log("Thread " + nThreadID + " is over!"); -5NP@  
bDownOver = true; B[ f{Ys  
//nPos = fileAccessI.write (b,0,nRead); B;8YX>r  
} I(8,D[G.m  
catch(Exception e){e.printStackTrace ();} pGi "*oZD  
} ? OBe!NDf  
} o} #nf$v(  
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bOCdf"!g  
//打印回应的头信息 N(?yOB4gt  
public void logResponseHead(HttpURLConnection con) ?ng?>!  
{ =+{.I,g}g@  
for(int i=1;;i++) *@Z/L26s;=  
{ ]xfAdBi  
String header=con.getHeaderFieldKey(i); x8T5aS  
if(header!=null) Ep}KIBBO  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); "F+ 9xf&r  
Utility.log(header+" : "+con.getHeaderField(header)); k@5,6s:  
else .2hQ!)+  
break; q[]!V0Ek10  
} $ 8w eh3p  
} r0kA47  
!^ 6x64r  
3V`K^X3  
public void splitterStop() q*A2>0O  
{ <Ebkb3_  
bStop = true; UD*#!H  
} ~}4o=O(  
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} ;,'!  
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/*  | qHWM  
**FileAccess.java z$-/yT"M  
*//文件访问(定位，写) _\"P<+!  
package NetFox; -p ) l63  
import java.io.*; CBSJY&:K  
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public class FileAccessI implements Serializable{ {H $\,  
5G){7]P+r"  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 D{.%Dr?  
RandomAccessFile oSavedFile; 7^KQQ([  
long nPos; {L$b$u$7:  
\\hZlCV,  
ynM{hN.+H  
public FileAccessI() throws IOException A i9*w?C  
{ 1y0.tdI(  
this("",0); 'xStA  
} 9qXHdpb#g"  
4PD"[a="  
r=L9x/r  
public FileAccessI(String sName,long nPos) throws IOException rxa"ji!)  
{ YhLtf(r  
oSavedFile = new RandomAccessFile(sName,"rw"); J~gfMp.  
this.nPos = nPos; _5 tw1 >  
oSavedFile.seek(nPos); -ZQ3^'f:0J  
} bvG").8$  
tsfOPth$*  
tx
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public synchronized int write(byte[] b,int nStart,int nLen) W]
2;5`MM  
{ 2z0HB+Y}x  
int n = -1; `Q(ac| 0  
try{ 'b661,+d  
oSavedFile.write(b,nStart,nLen); '12|:t&7  
n = nLen; @z/]!n\~  
} qZ\zsOnp  
catch(IOException e) @%\ANM$S  
{ +o'. !sRH  
e.printStackTrace (); q`$QroZT"  
} MqoQs{x  
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return n; BLaXp0  
} 'dU$QO  
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=l7
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} sM5 w~R>Y  
^G2vA8%  
3lL:vD5(  
/* B.P64"w  
**SiteInfoBean.java "BFW&<1  
*/ '|XP}V0I  
package NetFox; e/Q[%y.X  
5\4>H6  
<q[*kr  
public class SiteInfoBean { 'E&K%/d  
~:t2@z4p  
p\-.DRwT`  
private String sSiteURL; //Site's URL s}z,{Y$-t  
private String sFilePath; //Saved File's Path A+F-r_]}db  
private String sFileName; //Saved File's Name yPQ{tS*t  
private int nSplitter; //Count of Splited Downloading File GrQl3 Xi  
8V|-BP5^  
zfo.S[R@  
public SiteInfoBean() _-!
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{//nSplitter的缺省值为5 O4E2)N  
//default value of nSplitter is 5 |@ldXuYb  
this("","","",5); w5*18L=O\  
} ^U`q1Pg5  
<=7)t.  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) |Q I3H]T7  
{  +;
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sSiteURL= sURL; WX=+\`NyJ(  
sFilePath = sPath; P)\f\yb  
sFileName = sName; %@xYg{  
this.nSplitter = nSpiltter; KdR&OBm  
<.v6w*+{/  
n9J>yud|  
} [KE4wz+s{  
BuvBSLC~  
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public String getSSiteURL() CD tYj  
{ Q-au)R,  
return sSiteURL; 7>~iS@7GV  
} 5Y&@ :Y  
4[-9$ r  
j?mJ1J5  
public void setSSiteURL(String value) _0f[.vN  
{ 3AL.UBj&}  
sSiteURL = value; $I/p6  
} Y$Ke{6 4  
/vV 0$vg  
.Lp-'!i  
public String getSFilePath() d{trO;%#f  
{ LtU+w*Gj  
return sFilePath; wS^-o  
} v6n(<0:  
T*ic?!  
c"$_V[m  
public void setSFilePath(String value) -)Vj08aP  
{ [<`+9R  
sFilePath = value; Aa Ma9hvT!  
} 0x &^{P~  
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i~9)Hz
;!  
public String getSFileName() Cn<kl^!Q-  
{ |S8pq4eKJ_  
return sFileName; C,]Ec2  
} GGuLxc?(  
<@=NDUI3*,  
C;ye%&g>  
public void setSFileName(String value) W9D)QIqbvW  
{ l
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sFileName = value; 19vD(KC<  
} Mzd}9x$'J  
:W&\})  
fI|1@e1  
public int getNSplitter() ?c+;  
{ CMr`n8M  
return nSplitter; B::?  
} "osYw\unI  
dWUu3  
=3:ltI.'*I  
public void setNSplitter(int nCount) ~;W%s  
{ W{h7+X]Y  
nSplitter = nCount; RW)C<g  
} L;  ~=(  
} pi{ahuI#_o  
+ ThKqC_  
-5[GX
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/* ;$i'A&)OC  
**Utility.java )/JC.d#  
*/ a
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package NetFox; 6p@ts`#  
\2`U$3Q  
u&Fm}/x  
public class Utility { 6uyf  
dB5DJ:$W$  
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public Utility() U&XoT-p$L  
{ ]VME`]t`  
1}pR')YL[  
iiTUhO )  
} &)l:m.  
Xy{+=UY  
//线程睡眠 uE$o4X  
public static void sleep(int nSecond) ?1uAY.~ZZB  
{ K
0\WN"ua;  
try{ &g!/@*[Nhh  
Thread.sleep(nSecond); 9PAp*`J@kr  
} p1nA7;B-m  
catch(Exception e) 2&m7pcls  
{ L7-n
PH  
e.printStackTrace (); nM`)`!/  
} 3^Zi/r  
} ?q P}=nJ  
:9b RuUm  
//日志 >g&`g}xZQ  
public static void log(String sMsg) +*V; f,  
{ 7yp*I[1Qf>  
System.err.println(sMsg); $#r(1 Ev  
} 1N+#(<x@,
 
^n/uY94E)p  
l_c?q"X  
public static void log(int sMsg) lu_Gr=#O  
{ 5
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System.err.println(sMsg); Jy_'(hG  
} d eg>m?Y  
} v,&2!Zv  
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n  
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/* .D.Rn/  
**TestMethod.java l5FQ!>IM  
*/ umzYJ>2t  
package NetFox; Pcs@`&}7r  
|BW,pT  
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public class TestMethod { _LNPB$P  
7;NV 1RV  
2#3R]zIO  
public TestMethod() y`\Mhnj  
{ ///xx/weblogic60b2_win.exe 8GldVn.u  
try{ >Il`AR;D  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); +0Gep}&z.  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); @nu/0+8h{  
SiteFileFetch fileFetch = new SiteFileFetch(bean); TXcKuo=  
fileFetch.start(); YW<2:1A|  
} F6p1 VFs  
catch(Exception e){e.printStackTrace ();} WFP\;(YV  
h86={@Le  
w|C~{  
}
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t5h_Q92N  
>U?Bka!  
public static void main(String[] args) lWvd"Vlt  
{ gQWX<  
new TestMethod(); 2
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} Gq/6{eRo\  
} k5D'RD  
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