http断点续传简单实现（java)

/* A,<@m2  
**SiteFileFetch.java -!R l(if  
*/ &?T${*~  
package NetFox; /hci\-8N~  
import java.io.*; [W(Y3yyY  
import java.net.*; fPz=KoN  
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public class SiteFileFetch extends Thread { Zi1YZxF`Y  
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SiteInfoBean siteInfoBean = null; //文件信息Bean g:i*O^c@  
long[] nStartPos; //开始位置 t)(v4^T  
long[] nEndPos; //结束位置 3o0IjZ=[>  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 shK&2Noan  
long nFileLength; //文件长度 \=g!$  
boolean bFirst = true; //是否第一次取文件 pqfT\Kb>  
boolean bStop = false; //停止标志 NG)7G   
File tmpFile; //文件下载的临时信息 JtmQzr0>  
DataOutputStream output; //输出到文件的输出流 b|wWHNEdb,  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ~@fanR =  
public SiteFileFetch(SiteInfoBean bean) throws IOException vKkf2 7  
{ :?#cDyW)  
siteInfoBean = bean; =t.F2'<[Z  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); L>:FGNf^H  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); m X:bA5db  
if(tmpFile.exists ()) U_Y;fSl>  
{ 7'UWRRsxUF  
bFirst = false; |"\lL9CT  
read_nPos(); %kW3hQ<$  
} qKs7WBRJy  
else 2'dG7lLu4  
{ K#)bjxz  
nStartPos = new long[bean.getNSplitter()]; va+m9R0  
nEndPos = new long[bean.getNSplitter()]; =n)#!i  
} rgn|24x  
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} =U_@zDD@V  
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public void run() -;S3|  
{ F]SIT\kBm  
//获得文件长度 4^BLSK~(  
//分割文件 %Fm`Y.l
 
//实例FileSplitterFetch QvNi8TB  
//启动FileSplitterFetch线程 1Kc{#+a^  
//等待子线程返回 q8tug=c  
try{ U%Ol^xl  
if(bFirst) jL2MW(d^Q  
{ T-!|l7V~f  
nFileLength = getFileSize(); pfNThMf  
if(nFileLength == -1) 1W7 iip,  
{ 6(sfpK'  
System.err.println("File Length is not known!"); ugRV5bUk  
} KZ @l/s  
else if(nFileLength == -2) nu(eLUU  
{ K1 6s)S'  
System.err.println("File is not access!"); EK.c+Or,  
} r3?5'S`  
else m9cj7  
{
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for(int i=0;i<nStartPos.length;i++) fl!1AKSn@N  
{ '9Qd.q7s|b  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); E.Pje@d  
} \O,j}O'  
for(int i=0;i<nEndPos.length-1;i++) -ca]Q|m8  
{ 81cv:|"  
nEndPos = nStartPos[i+1]; tUn&z?7bF  
} 5 u
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nEndPos[nEndPos.length-1] = nFileLength; R+x%r&L5F  
} '>4+WZ1w5  
} 739l%u }<  
8Q)y%7{6  
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//启动子线程 Hv+:fr"  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; [lrmuf  
for(int i=0;i<nStartPos.length;i++)
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{ UU-v;_oP  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), }v,W-gA  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 
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nStartPos,nEndPos,i); |)*m[_1  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); .Wd.)^?  
fileSplitterFetch.start(); E)RI!0Ra  
}  -kV|  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), )lE3GDAPgZ  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 4bFv"b  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Zu)i+GeG  
nEndPos = " + nFileLength); 6Lav.x\W  
// fileSplitterFetch[nPos.length-1].start(); )3+xsnv  
m]  EDuW  
{lTR/  
//等待子线程结束 H,/~=d: ^  
//int count = 0; /{49I,  
//是否结束while循环 [%7IQ4`{  
boolean breakWhile = false; 60(}_%  
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.[]{
 Q  
while(!bStop) ~mHXz  
{ ^ON-#  
write_nPos(); ]i9H_K  
Utility.sleep(500); R4[. n@  
breakWhile = true; MM/BJ  
/5a$@%  
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for(int i=0;i<nStartPos.length;i++) cob9hj#&7  
{ a-SB1-5jf  
if(!fileSplitterFetch.bDownOver) {^2({A#&  
{ 4UkP:Vz:  
breakWhile = false; zDKLo 3:  
break; )^V5*#69D  
} VGkW3Nt0  
} Xd90n>4S  
if(breakWhile) >Lo6='G  
break; 7r:nMPX  
6:8EZ'y  
}UJdE#4  
//count++; 6kgCS{MZ  
//if(count>4) ~`tJvUo0  
// siteStop(); )1X' W  
} weTK#O0@v  
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<VauJB*R  
System.err.println("文件下载结束！"); *q\HFI  
} 5)/4)0  
catch(Exception e){e.printStackTrace ();} 6i*p +S?U"  
} *m `KU+o-u  
btr x?k(  
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//获得文件长度 N9fUlXhR  
public long getFileSize() QySca(1tN  
{ )x9nED{  
int nFileLength = -1; PaU@T!v  
try{ t*ri`}a{v  
URL url = new URL(siteInfoBean.getSSiteURL()); |
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); %-0em!tUV  
httpConnection.setRequestProperty("User-Agent","NetFox"); Q_UCF'f;}  
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int responseCode=httpConnection.getResponseCode(); &@
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if(responseCode>=400) 3P=Eb!qtdD  
{ ba8-XA_~U  
processErrorCode(responseCode); ~7eUt^SD;  
return -2; //-2 represent access is error qHcY 2LV  
} q?gQ  
;mM\, {Z  
6+{nw}e8  
String sHeader; ={wjeRp  
O(:u(U7e  
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for(int i=1;;i++) JXRmu~W~l  
{ 7J)a"d^e  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Nys'4kx7  
//Utility.log(in.readLine()); J$eZLj  
sHeader=httpConnection.getHeaderFieldKey(i); ^$Me#ls!  
if(sHeader!=null) $bM#\2'  
{ P+_\}u;  
if(sHeader.equals("Content-Length")) L?/M2zc9Y  
{ &Pn%zfmMN  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ?U2g8D nFY  
break; {H"=PYR  
} WZDokSR  
} Z_hBd['!  
else A~%g"  
break; :\ON+LQr  
} XEe+&VQmY  
} k(w9vt0?  
catch(IOException e){e.printStackTrace ();} }I'>r(K  
catch(Exception e){e.printStackTrace ();} q>Ar.5&M_  
`G:qtHn"Q<  
!:!@dC%8_  
Utility.log(nFileLength); ~O7cUsAi'  
?!Th-Cc&m  
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return nFileLength; &_Xv:?  
} "KQ\F0/  
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!x!L&p  
//保存下载信息（文件指针位置） } cH"lppX  
private void write_nPos() ^ZViQ$a"h;  
{ QKuc21  
try{ ybuSqFy`$  
output = new DataOutputStream(new FileOutputStream(tmpFile)); D%";!7u  
output.writeInt(nStartPos.length); ysw6hVb  
for(int i=0;i<nStartPos.length;i++) $SD@D6`lL  
{ IWbp^l+!t  
// output.writeLong(nPos); \T#(rt\j  
output.writeLong(fileSplitterFetch.nStartPos); CI3_lWax%  
output.writeLong(fileSplitterFetch.nEndPos); '~vSH9nx/  
} D} <o<Dk  
output.close(); KE|u}M@v6  
} d .l
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catch(IOException e){e.printStackTrace ();} 9zGKQ|X)  
catch(Exception e){e.printStackTrace ();}
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} &rtz&}Z
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//读取保存的下载信息（文件指针位置） ThiPT|5u  
private void read_nPos() nr9#3Lb  
{ :?of./Df|  
try{ W*WH .1&  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); SoON@h/  
int nCount = input.readInt(); mjr{L{H=?+  
nStartPos = new long[nCount]; "u$]q1S  
nEndPos = new long[nCount]; /)OO)B-r  
for(int i=0;i<nStartPos.length;i++) |$*9j""u  
{ j$i8@]  
nStartPos = input.readLong(); =.2cZwxX$  
nEndPos = input.readLong(); 6'lT`E|  
} $;j6*,H  
input.close(); U3iy
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} `0gK;D8t  
catch(IOException e){e.printStackTrace ();} \(7#N<-  
catch(Exception e){e.printStackTrace ();} s/'hLkxI  
} tNNg[;0  
b(rBha|  
0JWD] "  
private void processErrorCode(int nErrorCode) :usBeho  
{ :s5<AT Q  
System.err.println("Error Code : " + nErrorCode); (HD>vNha1  
} K{|dt W&  
`Q_ R/9~  
HC, 0"W  
//停止文件下载 o2UJ*4  
public void siteStop() z\ $>k_  
{ gJfL$S'w  
bStop = true; 8Nq Iz  
for(int i=0;i<nStartPos.length;i++) -bX.4+U  
fileSplitterFetch.splitterStop(); !suiqP1\*  
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} YVV $g-D}  
} NGD2z.  
//负责部分文件的抓取 5oyMR_yl  
**FileSplitterFetch.java RloPP  
*/ 03jBN2[!  
package NetFox; ialk6i![  
V\8 5  
9 7qS.Z27  
import java.io.*; 'cc4Y~0s  
import java.net.*; +}Wo=R
}  
aV%rq9Tp  
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public class FileSplitterFetch extends Thread { <(lSNGv5N  
?mUu(D:7D  
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String sURL; //File URL w)>z3Lm  
long nStartPos; //File Snippet Start Position ?)<XuMh  
long nEndPos; //File Snippet End Position xb_:9  
int nThreadID; //Thread's ID 31\^9w__8  
boolean bDownOver = false; //Downing is over gMMd=  
boolean bStop = false; //Stop identical :iC\#i]6  
FileAccessI fileAccessI = null; //File Access interface VNot4 62L  
1:Gd{z  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException c|a|z}(/J  
{ `lOoT  
this.sURL = sURL; L#N.pd  
this.nStartPos = nStart; KPcuGJ  
this.nEndPos = nEnd; O lIH0  
nThreadID = id; cf3c+.o  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ;|%JvptwW%  
} r1?FH2Ns  
Qz$Dv@*y\  
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public void run() S.4YC>E  
{ Q]:%Jj2  
while(nStartPos < nEndPos && !bStop) &Rt]K  
{ W,J,h6{F  
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try{ p&27|1pZm  
URL url = new URL(sURL); 4V3 w$:,  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 1qN9bwRO  
httpConnection.setRequestProperty("User-Agent","NetFox"); T+"y8#:  
String sProperty = "bytes="+nStartPos+"-"; 1/BMs0 =  
httpConnection.setRequestProperty("RANGE",sProperty); nU *fne?  
Utility.log(sProperty); `3n*4Lz  
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InputStream input = httpConnection.getInputStream(); LK5H~FK  
//logResponseHead(httpConnection); ea+rjvm  
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byte[] b = new byte[1024]; mf'1.{  
int nRead; Jjq%cA  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) I]
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{ zPc;[uHT  
nStartPos += fileAccessI.write(b,0,nRead); .AW*7Pp`f  
//if(nThreadID == 1) 9Q1GV>j>B  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); MF(~!SOIG  
} 3%a37/|~y  
:.Sc[UI0  
8;NO>L/J]i  
Utility.log("Thread " + nThreadID + " is over!"); P9^h>sV  
bDownOver = true; =*U24B*U93  
//nPos = fileAccessI.write (b,0,nRead); ~` hcgCi%  
} K),wAZI!7j  
catch(Exception e){e.printStackTrace ();} 21j+c{O  
} h;M2ylOu.  
} O~xmz!?=  
:wAB"TCt0  
I\23as0q  
//打印回应的头信息 ufPQ~,.  
public void logResponseHead(HttpURLConnection con) TZ2f-KI  
{ 1ouTZ'c?  
for(int i=1;;i++) z\5Nni/~6D  
{ 0wcWDE 9  
String header=con.getHeaderFieldKey(i); Q[KR,k  
if(header!=null) Shd,{Z)-Tg  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); }YO}LQ-|  
Utility.log(header+" : "+con.getHeaderField(header)); w}b+vh^3Wy  
else PEl]HI_H  
break; 7A-rF U$  
} 6iWuBsal  
} vm4oaVi  
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?Sxnq#r#  
public void splitterStop() 6f>HE'N  
{ `yXy T^  
bStop = true; -9"Ls?Cu  
} |L&V-f&K  
3MVZ*'1QM\  
I,;)pWX=@  
} 8msDJ{,X  
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Oa .%n9ec  
/* O=/Tx2i;  
**FileAccess.java )Cl&"bX  
*//文件访问(定位，写) Vba}RF[b  
package NetFox; rl=_ "sd=  
import java.io.*; ](D [T  
HfiM]^  
|O?Aj1g[c?  
public class FileAccessI implements Serializable{ 9g"H9)EZ^  
]Ox.6BKjDP  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 NM Ajt>t  
RandomAccessFile oSavedFile; ENzeVtw0  
long nPos; =qvU9p2o  
z
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Z}wAh|N-  
public FileAccessI() throws IOException H5{J2M,f  
{ wSMgBRV#^  
this("",0); CHB{P\WF  
} "/"k50%  
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d6VKUAk'7>  
public FileAccessI(String sName,long nPos) throws IOException |T%/d#b~  
{ |
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oSavedFile = new RandomAccessFile(sName,"rw"); {cA )jW\'  
this.nPos = nPos; L8J/GVmj  
oSavedFile.seek(nPos); }2@$2YR[  
}
:O%O``xT  
8Bvjj|~ (@  
10&A3C(E  
public synchronized int write(byte[] b,int nStart,int nLen) m.*+0NG  
{ Q~kwUZ  
int n = -1; u4'Lm+&O  
try{ .YkKIei  
oSavedFile.write(b,nStart,nLen); >Z%^|S9  
n = nLen; :xV&%Qa1  
} /[
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catch(IOException e) HChewrUAn  
{ "<WSEs  
e.printStackTrace (); ~6nQ-  
} V1G]LM  
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return n; DxBt83e  
} K&*FI (a  
rSk $]E]Z  
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} slx^" BF^  
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h:;~)={"X  
/* L!Ro`6|7;  
**SiteInfoBean.java `6A"eDa  
*/ ]Vsze4>Z[  
package NetFox; c2nZd.SD|  
>XF@=Jp  
LHz{*`22q  
public class SiteInfoBean { L8fr uwb  
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/iK )tl|X  
private String sSiteURL; //Site's URL G-qxQD1wK  
private String sFilePath; //Saved File's Path ) l)5^7=W  
private String sFileName; //Saved File's Name jd{J3s '%  
private int nSplitter; //Count of Splited Downloading File ]~P?  
4)ISRR  
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public SiteInfoBean() 0[];c$r<  
{//nSplitter的缺省值为5 uFqH_04  
//default value of nSplitter is 5 BSz\9 eT  
this("","","",5); e.T5F`Du  
} -=RXhE_{  
2g$Wv :E3  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) j405G4BVW  
{ vcmS]$}  
sSiteURL= sURL;
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sFilePath = sPath; y^ :x2P  
sFileName = sName; [{ pc1U-  
this.nSplitter = nSpiltter; BK{8\/dg  
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R3~&|>7/T  
} 8C2t0u;Y .  
s|%</fMt9  
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public String getSSiteURL() Cur)|  
{ 01Aa.i^d(  
return sSiteURL; qr@,92_  
} Czp:y8YX-  
uxcj3xE#d  
!qR(Rn  
public void setSSiteURL(String value) 0KZ 3h|4lP  
{ Hq9(6w9w  
sSiteURL = value; iT%UfN/q=I  
} sxqXR6p{  
,LW0{(&z  
,d7@*>T&  
public String getSFilePath() +a|4XyN  
{ 09"~<W8  
return sFilePath; _RmrjDk  
} c"~TH.,d  
W%P&o}'  
^Ni)gm{?k  
public void setSFilePath(String value) +$-a:zx`l  
{ *+IUGR  
sFilePath = value; ~EN@$N^h  
} v<) }T5~r  
)Q8Q#
S  
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public String getSFileName() itP_Vxo/H  
{ ()?)Ybqss  
return sFileName; pv T!6+  
} \|(;q+n?k  
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public void setSFileName(String value) k\lj<v<vD  
{ \!PC:+uJ  
sFileName = value; wqyAEVea'8  
} ~t}:vGDj  
Q>rQ/V  
gO5;hd[l  
public int getNSplitter() J kA~Ol  
{ +bSv-i-  
return nSplitter; n33SWE(  
} {ys_uS{c*  
kO.rgW82  
._yr7uY[M  
public void setNSplitter(int nCount) 0Zq"-  
{ HwcGbbX)  
nSplitter = nCount; eAqQ~)8^  
} l YhwV\3  
} O<Kr6+ -  
gW
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/* XBc+_=)$  
**Utility.java 
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*/ "mOoGy,(  
package NetFox; ]D%[GO//!  
;gc2vDMv  
o ZAjta_4  
public class Utility { +n:#Uf)  
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$xl*P#  
public Utility() " JRlj  
{ WULj@ds\~
 
$^l=#tV  
&a0%7ea`.S  
} F^\v`l,  
Bj2rA.
M  
//线程睡眠 brFOQU?  
public static void sleep(int nSecond) 6!'yU=Z`  
{ :eO]65N  
try{ }}]Y mf  
Thread.sleep(nSecond); F-X>|oK>z  
} & #|vGhA  
catch(Exception e) rS jC/O&b  
{ qEpBzQ&gX6  
e.printStackTrace (); g&[g?L  
} 9\;EX  
} V *]!N  
qM`SN4C  
//日志 Vlf@T  
public static void log(String sMsg) 5 909O  
{  2AluH8X/  
System.err.println(sMsg); ,s2.l/5r;C  
} YK-R|z6K  
&sRyM'XI  
WP>O7[|  
public static void log(int sMsg) @s/ qOq?  
{ #B?7{#.1  
System.err.println(sMsg); &#;,P:.'  
} 9GEcs(A*  
} `+gF|o9  
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I@\{6
hw  
/* ]uZH  0  
**TestMethod.java u-W=~EO5#  
*/ 51&T`i  
package NetFox; f8j^a?d|
  
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public class TestMethod { lL^7x  
cnj_tC=zt  
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public TestMethod() nGf@zJDb  
{ ///xx/weblogic60b2_win.exe E|TzrH  
try{ 3_-#
 
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); xq{4i|d)  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); :K~7BJ(HO  
SiteFileFetch fileFetch = new SiteFileFetch(bean); WZMsmhU@T  
fileFetch.start(); iO@wqbg$6  
} ^Nu} HcC+  
catch(Exception e){e.printStackTrace ();} @Q^;qMy  
@4|/| !  

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} "gO5
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ALv\"uUNu+  
public static void main(String[] args) -1o1k-8d  
{ Mc8^{br61  
new TestMethod(); 83h3C EQ  
} v+OVZDf  
} jQDxbkIuzE  
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