http断点续传简单实现（java)

/* utQE$0F  
**SiteFileFetch.java ^u:7U4  
*/ <O?iJ=$  
package NetFox; ZBcZG  
import java.io.*; 26yv w  
import java.net.*; '73dsOTIT  
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public class SiteFileFetch extends Thread { ?a7PxD.  
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SiteInfoBean siteInfoBean = null; //文件信息Bean X7?p$!M6;B  
long[] nStartPos; //开始位置 9loWh5_1Z  
long[] nEndPos; //结束位置 8*H-</ =  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 \ZigG{  
long nFileLength; //文件长度 S WVeUL#5  
boolean bFirst = true; //是否第一次取文件 x %L2eXL  
boolean bStop = false; //停止标志 k8F<j)"  
File tmpFile; //文件下载的临时信息 I0(BKMp&  
DataOutputStream output; //输出到文件的输出流 (8qMF{  
n%"q>  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） >:Na^+c  
public SiteFileFetch(SiteInfoBean bean) throws IOException "nU5c4   
{ efy65+~GG  
siteInfoBean = bean; ?5Wjy  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); yaMNt}y-q
 
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 6,G1:BV{K  
if(tmpFile.exists ()) wxkCmrV  
{  nk>  
bFirst = false; 3DV';  
read_nPos(); ePq(:ih  
} a57Y9.H`o  
else :`2<SF^0O  
{ A)kx,,[  
nStartPos = new long[bean.getNSplitter()]; ]U!vZY@\  
nEndPos = new long[bean.getNSplitter()]; 4{(uw  
} X,IjM&o"Y  
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} 4[ M!x  
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public void run() ,3.E]_3xX  
{ L)a8W   
//获得文件长度 OKNA36cU'  
//分割文件 YFv/t=`  
//实例FileSplitterFetch FAfk;<#'n+  
//启动FileSplitterFetch线程 x9Y1v1!5Pu  
//等待子线程返回 hF s:9  
try{ 5DK>4H:  
if(bFirst) K~H)XJFF  
{ K:Wxx"  
nFileLength = getFileSize(); i6?,2\K  
if(nFileLength == -1) L@HPU;<  
{ l_hM,]T0  
System.err.println("File Length is not known!"); P,k~! F^L  
} _7'9omq@  
else if(nFileLength == -2) 8*!<,k="9  
{ mTz %;+|L  
System.err.println("File is not access!"); ]|it&4l  
} Tz4,lwuWX7  
else V%8?f,  
{ NZ
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for(int i=0;i<nStartPos.length;i++) R 5-q{  
{ "CLoM\M)  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ym9Z:2g  
} p~6/+ap  
for(int i=0;i<nEndPos.length-1;i++) "+/%s#&  
{ ?:vp3f#  
nEndPos = nStartPos[i+1]; 9un]}7^  
} n$ $^(-g@)  
nEndPos[nEndPos.length-1] = nFileLength; lqn7$
 
} 
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} 5ppO
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(9% ki$=}+  
//启动子线程 bXF>{%(}E  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; %@#+Xpa+  
for(int i=0;i<nStartPos.length;i++) ^hzlR[  
{ f uQbDb&  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), $h`(toTyF  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), !O6e,l  
nStartPos,nEndPos,i); T$T:~8tK3  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Aayh'xQ  
fileSplitterFetch.start(); gKeqf-UWKJ  
} g6{
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// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), .<
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ig<Eyr  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", v".q578 0B  
nEndPos = " + nFileLength); fftFNHP  
// fileSplitterFetch[nPos.length-1].start(); JQ=i{
9iJ  
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//等待子线程结束 g}"`@H(9r3  
//int count = 0; xI}o8GKQq  
//是否结束while循环 k"D6Vyy`  
boolean breakWhile = false; XTEC0s"F  
0D/u`-  
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while(!bStop) c[\ :^w^I6  
{ lffp\v{w  
write_nPos(); ZUP\)[~  
Utility.sleep(500); M #'br<]  
breakWhile = true; x;)bp7
 
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for(int i=0;i<nStartPos.length;i++) 0T7(c-  
{ 
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if(!fileSplitterFetch.bDownOver) %a=K:" oU[  
{ I$/*Pt];  
breakWhile = false; ^]l^q
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break; HM57b>
6  
} 1+6:K._C(m  
} ~\kJir  
if(breakWhile) s7.2EkGl=  
break; W
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b~fX=!M  
//count++; A<P3X/i  
//if(count>4) bwo-9B  
// siteStop(); KiY
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} $2B_a  
^ CVhV  
xxkUu6x#  
System.err.println("文件下载结束！"); /WlK*8C  
} Atsi}zTR\  
catch(Exception e){e.printStackTrace ();} jXA!9_L7  
} 6hDK;J J&  
b?9c\-}  
o#3?")>|  
//获得文件长度 y_EkW f  
public long getFileSize() Tlrr02>B{  
{ IN=pki|.  
int nFileLength = -1; VH[r@Pn  
try{ |T?wM/  
URL url = new URL(siteInfoBean.getSSiteURL()); sqTBlP  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Ay)q %:qx  
httpConnection.setRequestProperty("User-Agent","NetFox"); 3D_Ky Z~M+  
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int responseCode=httpConnection.getResponseCode(); 8|^
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if(responseCode>=400) L#sw@UCK  
{ \{r-e  
processErrorCode(responseCode); fm$eJu  
return -2; //-2 represent access is error t`NZ_w /  
} Dy6uWv,P  
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String sHeader; +Go(yS  
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=B4,H=7Spf  
for(int i=1;;i++) HUqG)t*c1  
{ OQzJRu)mF#  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); F*V<L   
//Utility.log(in.readLine()); <!b~7sZkTc  
sHeader=httpConnection.getHeaderFieldKey(i); r=GF*i[3  
if(sHeader!=null) q/y4HT,x  
{ _y#omEx  
if(sHeader.equals("Content-Length")) HT]W2^k  
{ #qkokV6`  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ZeewGa^r  
break; ' >(])Oq,  
} HQHFD0hv  
} 1'ne[@i^/  
else sX&.8  
break; d"3S[_U  
} tHNvb\MR$  
} 50!/%  
catch(IOException e){e.printStackTrace ();} w-2&6o<n-  
catch(Exception e){e.printStackTrace ();} QZy+`  
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Utility.log(nFileLength); / hUuQDJ  
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' JHCf  
return nFileLength; 5 o:VixZf  
} &<I*;z6%t  
*r!f! eA:  
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//保存下载信息（文件指针位置） csn/h$`-@  
private void write_nPos() D'V0
b"  
{ TDI8L\rr  
try{ wMy$T<:   
output = new DataOutputStream(new FileOutputStream(tmpFile)); }e3M5LI1L  
output.writeInt(nStartPos.length); .C^1.)  
for(int i=0;i<nStartPos.length;i++) DLMG<4Cd~  
{ e$F]t*)Xa  
// output.writeLong(nPos); z;1y7W!v  
output.writeLong(fileSplitterFetch.nStartPos); %bI(  
output.writeLong(fileSplitterFetch.nEndPos); |8I
#`  
} z0J$9hEg89  
output.close(); ^NJ]~h{n$  
} 2 qRXA  
catch(IOException e){e.printStackTrace ();} Y" 9 o  
catch(Exception e){e.printStackTrace ();} 1*S
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} p:M#F:  
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//读取保存的下载信息（文件指针位置） !:e|M|T'I*  
private void read_nPos() 7q bGA K  
{ b *IJ +  
try{ ~~:w^(s9  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); j,Sg?&"%=  
int nCount = input.readInt(); [c4.E"  
nStartPos = new long[nCount]; :V2"<]  
nEndPos = new long[nCount]; @rs(`4QEh  
for(int i=0;i<nStartPos.length;i++) R"(rL5j  
{ v-6"*EP  
nStartPos = input.readLong(); ?fv?6r  
nEndPos = input.readLong(); qGMM3a)Q  
} h&4ufx6  
input.close(); a]:tn:q  
} U$a Eby.  
catch(IOException e){e.printStackTrace ();} SsA;T5:6  
catch(Exception e){e.printStackTrace ();} _3$@s{k-TI  
} gr %8 O-n  
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private void processErrorCode(int nErrorCode) 0P`wh=")  
{ `mPmEV<  
System.err.println("Error Code : " + nErrorCode); ^_4TDC~h  
} ~ZU;0#  
C("PCD   
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'>r_.  
//停止文件下载 CG'NC\x5  
public void siteStop() &{QB}r  
{ &SS"A*xg  
bStop = true; ToNi<~  
for(int i=0;i<nStartPos.length;i++) 8?] :>  
fileSplitterFetch.splitterStop();  {ZFa +  
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} Mq) n=M  
} E#"QaI8`  
//负责部分文件的抓取 \C.%S +u  
**FileSplitterFetch.java 1"46OCu{  
*/ 9dA(f~  
package NetFox; A9PXu\%y  
q0WW^jwQ  
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import java.io.*; =/=x"q+X  
import java.net.*; 2{s ND  
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public class FileSplitterFetch extends Thread { j`Lf/S!}  
iHjo3_g)n  
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String sURL; //File URL 7=XQgbY/  
long nStartPos; //File Snippet Start Position  l|`FW  
long nEndPos; //File Snippet End Position XuJwZN!(  
int nThreadID; //Thread's ID J#*Uf>5NY  
boolean bDownOver = false; //Downing is over lEi,duS)  
boolean bStop = false; //Stop identical Fk D  
FileAccessI fileAccessI = null; //File Access interface mOwgk7s[J  
:NU-C!eT  
s#w+^Mw$  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException  N>`+{  
{ "M6a_rZ2W  
this.sURL = sURL; #1Mk9sxo  
this.nStartPos = nStart; I^Ichn  
this.nEndPos = nEnd; *
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nThreadID = id; @RotJl/>  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 etf ft8  
} La%\-o  
7UHqiA`L  
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public void run() Z_' %'&Y  
{ T
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while(nStartPos < nEndPos && !bStop) *pP"u::S  
{ 0kgK~\^,.O  
cb&y8!ci~  
t )Z2"_5  
try{ 5X&<+{bX  
URL url = new URL(sURL); Bir}X  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); oSNB\G<  
httpConnection.setRequestProperty("User-Agent","NetFox"); %9M; MK  
String sProperty = "bytes="+nStartPos+"-"; D{o1G?A  
httpConnection.setRequestProperty("RANGE",sProperty); yP0P-8  
Utility.log(sProperty); iMx+y5O  
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InputStream input = httpConnection.getInputStream(); pALB[;9g  
//logResponseHead(httpConnection); )xQxc.  
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byte[] b = new byte[1024]; ~m!>e])P?X  
int nRead; !N$4.slr<p  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) =D5@PHpv(  
{ p@i U}SUaE  
nStartPos += fileAccessI.write(b,0,nRead); qNHS 1  
//if(nThreadID == 1) w GZ(bKyO  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); *" <tFQ  
} {N5g52MN  
7~\Dzcfk"P  
4:r^6m%%  
Utility.log("Thread " + nThreadID + " is over!"); zq!2);,  
bDownOver = true; :&yRvu  
//nPos = fileAccessI.write (b,0,nRead); !Go(8`>  
} VK`_Qc#B  
catch(Exception e){e.printStackTrace ();} :EgdV  
} CW\o>yh  
} OpxVy _5,  
yD1*^~loJ  
2DQ'h}BI  
//打印回应的头信息 yE9JMi0  
public void logResponseHead(HttpURLConnection con) ?^BsR  
{ 1@)]+* F*z  
for(int i=1;;i++) gbpm::  
{ k6JB%m\E  
String header=con.getHeaderFieldKey(i); $pk3d+0B  
if(header!=null) i`&yPw  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ]kb%l"&  
Utility.log(header+" : "+con.getHeaderField(header)); vzi=[A  
else b]RCe^E1  
break; 344,mnAd  
} j,/o0k,  
} W\.f:"2qr  
>[|:cz  
#*S/Sh?Q  
public void splitterStop() 1bzPBi  
{ ;ok];4`a  
bStop = true; 6FEtq,;0w  
} aS~k.^N  
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} x?CjRvT$  
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/* eg(xN/D  
**FileAccess.java {h9#JMIA  
*//文件访问(定位，写) );))kYr  
package NetFox; 9k7|B>LT  
import java.io.*; "6Dz~5  
n
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/SMp`Q88  
public class FileAccessI implements Serializable{ S\0"G*  
:\80*[=;Z  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 #S<>+,Lk  
RandomAccessFile oSavedFile; }GkEv}~t  
long nPos; nWXI*%m5  
:Hd?0eZ|  
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public FileAccessI() throws IOException ,}{E+e5jh7  
{ =Rb,`%  
this("",0); $Fr2oSTT)  
} M8juab%y  
rcI(6P<*  
;uoH+`pf  
public FileAccessI(String sName,long nPos) throws IOException K?I@'B'  
{ 1Za\T?V  
oSavedFile = new RandomAccessFile(sName,"rw"); I">z#@CT  
this.nPos = nPos; P:*'x9`  
oSavedFile.seek(nPos); ZlO@PlZ)  
}
#{h4lte  
|{9"n<JW  
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public synchronized int write(byte[] b,int nStart,int nLen) 1M3U)U  
{ yvH:U5%  
int n = -1; d=>5%$:v  
try{ 0*g psS  
oSavedFile.write(b,nStart,nLen); uN$X3Ls_  
n = nLen; 1GEE^Eu  
} ;7m>40W  
catch(IOException e) 8l='Hl  
{ kOtC(\]5  
e.printStackTrace (); tOspDPSXX  
} $u3N',&  
4
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return n; v11mu2  
} H[>_LYZ8  

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} i6X/`XW'  
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.7)A8R7Wt  
/* gpw(j0/Fs  
**SiteInfoBean.java /u #9M {  
*/ B1Lnu
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package NetFox; *\joaw  
l,v:[N  
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public class SiteInfoBean { ,%KB\;1mn'  
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|xf%1(Rl@  
private String sSiteURL; //Site's URL tS!~>X  
private String sFilePath; //Saved File's Path gcv,]v8  
private String sFileName; //Saved File's Name N}dJ)<(2~  
private int nSplitter; //Count of Splited Downloading File pg>P]a{  
-9aht}Z  
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public SiteInfoBean() *K+*0_  
{//nSplitter的缺省值为5 G %#us3x  
//default value of nSplitter is 5 F5MWxAS,>  
this("","","",5); s#d# *pgzh  
} t8P>s})[4  
55!9U:{  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) gH_r'j  
{ +-.BF"}  
sSiteURL= sURL; 1%-?e``.
 
sFilePath = sPath; MiSFT5$v6  
sFileName = sName; Ab(bvS8r$  
this.nSplitter = nSpiltter; Cog:6Gnw  
c3 wu&*p{  
tXp)o>"  
} 2XI%4  
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,U2D&{@  
public String getSSiteURL() <v2R6cj5  
{ i5AhF\7F9  
return sSiteURL; [0~qs|27  
} >K &b,o,[  
'.d
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#Kh`ATme  
public void setSSiteURL(String value) Mq7|37(N[  
{ $K,aLcu  
sSiteURL = value; f a\cLC  
} fe0 Y^vW  
&c\8`# 6  
{==Q6BG*  
public String getSFilePath() de`6%%|  
{ ZO;]Zt]  
return sFilePath; v$mA7|(t!  
} ~cZ1=,
P  
19=Dd#Nf  
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public void setSFilePath(String value) | 'z)RFqj  
{ I+<;Dsp  
sFilePath = value; =k8
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} +L49 pv5  
~}M{[6!  

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public String getSFileName() "Km`B1f`  
{ K3Xy%pqR#  
return sFileName; *Z0}0< D@Z  
} @+2Zt%  
%(e=Q^=  
_ Po9pZ  
public void setSFileName(String value) Ec[:6}  
{ 6@$[x* V  
sFileName = value; ' 5Ieqpm9  
} au7BqV!uL  
{Ise (>V  
\agC Q&  
public int getNSplitter() ?3|ZS8y  
{ eU12*(  
return nSplitter; )l"0:1Ig  
} L*l( ~t)vF  
V*TG%V -  
b,@:eVQ7  
public void setNSplitter(int nCount) 2`},;i~[  
{ bc"{ZL!C  
nSplitter = nCount; z7K?rgH  
} "ulaF+  
} JBYQ7SsAS0  
 qJK^i.e  
2cDC6rul  
/* 
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**Utility.java ._R82gy  
*/ "d#s|_n,d)  
package NetFox; K)14v;@  
<AIsNqr  
&B.r&K&  
public class Utility { dn5v|[dJ  
eGE%c1H9a  
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public Utility() BNByaC  
{ IM#+@vv  
=?2y <B  
c]LH.  
} eJwr  
L"Gi
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//线程睡眠 *[U:'o`67  
public static void sleep(int nSecond) Po_9M4kU  
{ 4H,DG`[Mo  
try{ z_H2L"Z  
Thread.sleep(nSecond); 2Fh_  
} &p%,+|  
catch(Exception e) jmb\eOq+~V  
{ 63f/-64?7  
e.printStackTrace (); 'L m `L<`  
} G'epsD,.bX  
} b'&pJ1]]}  
w Vof_'F1  
//日志 [X I5Bu ~  
public static void log(String sMsg) Cse0!7_T  
{ \xdt|:8  
System.err.println(sMsg); p"JSYF 9]  
} EW!$D  
A
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tL5Xfd?u  
public static void log(int sMsg) }/LYI  
{ I*ej_cFQ^  
System.err.println(sMsg); }n.h)Oz  
} pta%%8":  
} 0L1P'*LRU  
;L[9[uQ[C  
i-<=nD&?t  
/* A`r9"([-A  
**TestMethod.java Ao\Vh\rQkq  
*/ 8x{vgx @M  
package NetFox; wv7jh~x(4  
cC[n~OV  
k@~-|\ooG  
public class TestMethod { B -KOf  
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79V5{2Y*U  
public TestMethod() K c<z;
 
{ ///xx/weblogic60b2_win.exe zm:=d>D..  
try{ UVLcR  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); =?lT&|"  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); <_>6a7ra  
SiteFileFetch fileFetch = new SiteFileFetch(bean); /;0>*
ft4  
fileFetch.start(); d{he  
} EH:1Z*|Z{\  
catch(Exception e){e.printStackTrace ();} q^cFD  
<Z;7=k  
&SM$oy#?  
} ^M9oTNk2  
P=@lkF!\#  
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public static void main(String[] args) Q.XsY.{  
{ ,dp?'_q{  
new TestMethod(); pxbNeqK@p  
} hK"=~\,  
} lEDHx[q  
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