http断点续传简单实现（java)

/* ,9ueHE  
**SiteFileFetch.java `C>h]H(  
*/ \;0pjxq=  
package NetFox; d8: $ll  
import java.io.*; EcH
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import java.net.*; Hj >fg2/  
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public class SiteFileFetch extends Thread { fh =R  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ;b [>{Q;  
long[] nStartPos; //开始位置 Q I";[  
long[] nEndPos; //结束位置 co\?SgE35  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 q,fp DNo  
long nFileLength; //文件长度 oX)a6FXK>  
boolean bFirst = true; //是否第一次取文件 &;ddnxFI  
boolean bStop = false; //停止标志 8x1!15Wiz  
File tmpFile; //文件下载的临时信息 @].s^ss9_  
DataOutputStream output; //输出到文件的输出流 Kc]cJ`P4.  
:j+E]|d(~6  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） |h $Gs2  
public SiteFileFetch(SiteInfoBean bean) throws IOException =&pR=vl  
{ TSFrv8L  
siteInfoBean = bean; Q3ZGN1aX<  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); %. ((4 6)  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); :c]y/lQmV  
if(tmpFile.exists ()) 9ls1y=M8J  
{ ;VCV%=W<  
bFirst = false; 6T4"m  
read_nPos(); iOa<=  
} <6]Hj2  
else MDa[bQNM  
{ FsUH/Y y  
nStartPos = new long[bean.getNSplitter()]; 0*:n<T9  
nEndPos = new long[bean.getNSplitter()]; Z=
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} 9hK8dJw  
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V  
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} bL<H$DB6  
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public void run() EO'+r[Y  
{ n)cc\JPQ  
//获得文件长度 br0\O  
//分割文件 f(}&8~&  
//实例FileSplitterFetch miBCq
l@x  
//启动FileSplitterFetch线程 bg3kGt0  
//等待子线程返回 m?Jnb\0  
try{ e+Mm!\;`  
if(bFirst) :zC=JvKT  
{ 7 HL Uk3  
nFileLength = getFileSize(); U#Kw+slM  
if(nFileLength == -1) +:#g6(P]  
{ 4myikeUR_  
System.err.println("File Length is not known!"); 9[{q5  
} #/(L.5d[  
else if(nFileLength == -2) z4.|N  
{ x6T$HN/2  
System.err.println("File is not access!"); T8L
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} LUx'Dm"  
else ^l(,'>Cn  
{ k?pNmKVJM  
for(int i=0;i<nStartPos.length;i++) Qc9
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{ RionKi
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); 7}=MVp] )S  
} 2Sy:wt  
for(int i=0;i<nEndPos.length-1;i++) $43CNnf3N  
{ `ER#S_}  
nEndPos = nStartPos[i+1]; H6#SP~V  
} 6jal5<H  
nEndPos[nEndPos.length-1] = nFileLength; 5=poe@1g  
} }/xdHt  
} z1e+Ob&  
&@&^k$du8q  
0,LUi*10  
//启动子线程 ,;= S\  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; "g!/^A!!  
for(int i=0;i<nStartPos.length;i++) TTxSl p2=;  
{ o5z&sRZ  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), IgF#f%|Q  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), \Zk<|T61$  
nStartPos,nEndPos,i); d D^?%,a  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); YBk* CW9  
fileSplitterFetch.start(); j1@PfKh  
} H#`&!p  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ,+_gx.H2j  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 6`'KM/  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", SkXx:@  
nEndPos = " + nFileLength); 3t]0  
// fileSplitterFetch[nPos.length-1].start(); >F!X'#Iv  
L!W5H2Mc  
du=[r  
//等待子线程结束 wlX K2D  
//int count = 0; ubi6=  
//是否结束while循环 TP/bPZY  
boolean breakWhile = false; +Kg3qS"  
|VX0o2  
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while(!bStop) E+aE5wmr  
{ ]O68~+6  
write_nPos(); ?Qh[vcF7`  
Utility.sleep(500); FiNB$A  
breakWhile = true; cp 7;~i3  
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'~Gk{'Nx"  
for(int i=0;i<nStartPos.length;i++) .$-%rU:*}  
{ 8F`799[p  
if(!fileSplitterFetch.bDownOver) T+<OlXpL  
{ Zv1/J}+  
breakWhile = false; {&Sr<d
5  
break; u!VY6y7p  
} F|W(_llfM  
} `lq[6[n  
if(breakWhile) ,G(bwE9~  
break; _;5N@2?  
!p"Ijz5  
TYr"yZ([
 
//count++; Ja6PX P]'  
//if(count>4) 9ioV R  
// siteStop(); IDv|i.q3  
} B6a   
0--0+?  
<q#/z&F!  
System.err.println("文件下载结束！"); P&]PJt5  
} f<~S0[H  
catch(Exception e){e.printStackTrace ();} < {dV=  
} 9l9|w4YJs  
MDKiwT@#  
L%O( I  
//获得文件长度 Lv?e[GA  
public long getFileSize() (!`]S>_w9  
{
vErlh:~e  
int nFileLength = -1;
rN^P//  
try{ T8rf+B/.L  
URL url = new URL(siteInfoBean.getSSiteURL()); v5o@l
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); -( ,iwFb  
httpConnection.setRequestProperty("User-Agent","NetFox"); t{)J#8:g  
DN;An0 {MK  
.!hB t
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int responseCode=httpConnection.getResponseCode(); ;iEFG^'tG  
if(responseCode>=400) 0<T/P+|  
{ ~'l.g^p bv  
processErrorCode(responseCode); F[SY
s/M  
return -2; //-2 represent access is error !EQMTF=(  
} oUwu:&<Orm  
:X6A9jmd  
6-@n$5W0  
String sHeader; SQB[d3f  
h0fbc;l  
o!+jPwEU  
for(int i=1;;i++) Q@lJ|  
{ M6b; DQ  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); h[
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//Utility.log(in.readLine()); T;%ceLD  
sHeader=httpConnection.getHeaderFieldKey(i); wz P")}[0  
if(sHeader!=null) \;>idbV  
{ b}[W[J}`  
if(sHeader.equals("Content-Length")) -l!;PV S|  
{ PiRbdl  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); An e.sS  
break; ZdD]l*.\i  
} ^r<bi%@C$  
} q)uq?sZe  
else {]}}rx'|P  
break; J8x>vC  
} P2`!)teN  
} F:CqB|  
catch(IOException e){e.printStackTrace ();} EK^ld!g(  
catch(Exception e){e.printStackTrace ();} 7 C5m#e3  
@])q
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dfo{ B/+  
Utility.log(nFileLength); j_?U6$xi  
yp=2nU"o  
* SG0-_S  
return nFileLength; Xa2QtJq  
} m(Cn'@i`"0  
sYt8NsQ  
o(. PxcD  
//保存下载信息（文件指针位置） (s,*soAN  
private void write_nPos() ]y,6  
{ D'>yu"  
try{ |/g\N,]  
output = new DataOutputStream(new FileOutputStream(tmpFile)); hIw<gb4J%  
output.writeInt(nStartPos.length); %cD7}o:u  
for(int i=0;i<nStartPos.length;i++) e/WR\B'1  
{ "~4ULl<i'  
// output.writeLong(nPos); bf `4GD(  
output.writeLong(fileSplitterFetch.nStartPos); M[0@3"}}  
output.writeLong(fileSplitterFetch.nEndPos); Frt_X%  
} YXH9Q@Gn  
output.close(); v!ULErs  
} "6n~,$  
catch(IOException e){e.printStackTrace ();} J%3%l5/  
catch(Exception e){e.printStackTrace ();} LD WFc_  
} er}/~@JJ  
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:JSOj@s  
//读取保存的下载信息（文件指针位置） ~)}npS;  
private void read_nPos() #zXkg[J6d  
{ OFCOMM  
try{ "7RQrz  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); PKu+$  
int nCount = input.readInt(); !E> *Mn  
nStartPos = new long[nCount]; 8@qYzSx[  
nEndPos = new long[nCount]; L '342(  
for(int i=0;i<nStartPos.length;i++) 4)iSz>  
{ X#(?V[F]  
nStartPos = input.readLong(); =_8  
nEndPos = input.readLong(); 8|?$KLz?F>  
} @q2Yka  
input.close(); #P-S.b  
} &M~*w~w`  
catch(IOException e){e.printStackTrace ();} 0W9,uC2:N  
catch(Exception e){e.printStackTrace ();} ^l ~i>:V  
} ycRy!0l  
[X=-x=S,  
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private void processErrorCode(int nErrorCode) )=;0  
{ A5+vzu^  
System.err.println("Error Code : " + nErrorCode); ^!1mChf  
} zO2Z\E'%.  
6Ez}A|i  
wCvtw[6  
//停止文件下载 |~CN]N  
public void siteStop() f5Zx:g  
{ (H<S&5[  
bStop = true; 2Q)"~3  
for(int i=0;i<nStartPos.length;i++) mKPyM<Q  
fileSplitterFetch.splitterStop(); Z= dEk`  
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} E:(flW=  
} ;_,=  
//负责部分文件的抓取 ykxjT@[  
**FileSplitterFetch.java 0CQ\e1S,#  
*/ AIF?+i%H}  
package NetFox;
V(A6>0s$|  
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d /jO~+jP  
import java.io.*; *n N;!*J  
import java.net.*; UC;_}>  
7:I` ~ @m  
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public class FileSplitterFetch extends Thread { L=Fm:O'#2  
T#Qn\8  
0~H(GG$VH  
String sURL; //File URL #q%xJ[  
long nStartPos; //File Snippet Start Position vdYd~>w  
long nEndPos; //File Snippet End Position A{Z=[]r1`E  
int nThreadID; //Thread's ID d3+pS\&IX?  
boolean bDownOver = false; //Downing is over 9l@VxX68M  
boolean bStop = false; //Stop identical :O{`!&[>L  
FileAccessI fileAccessI = null; //File Access interface ync2X{9D  
9Y- Sqk+  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException s@E"EWp0  
{ YW}q@AY7  
this.sURL = sURL; Bl2y~fCA  
this.nStartPos = nStart; KTD# a1W  
this.nEndPos = nEnd; En&ESWN  
nThreadID = id; AKC';J  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Aj#CB.y  
} E9;cd$}K  
Vz!W(+  

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public void run() 'xm_oGWE  
{ ~z$vF  
while(nStartPos < nEndPos && !bStop) 57Q^"sl  
{ ".O+";wk  
\]e"#"v}}_  
 `@b+'L  
try{ D'F=v\P  
URL url = new URL(sURL); UJ1iXV[h"  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 5m!FtHvm1  
httpConnection.setRequestProperty("User-Agent","NetFox"); B?'`\q)UL  
String sProperty = "bytes="+nStartPos+"-"; W
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httpConnection.setRequestProperty("RANGE",sProperty); 4pq@o  
Utility.log(sProperty); dkt'~  
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0
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InputStream input = httpConnection.getInputStream(); Mdsn"Y V  
//logResponseHead(httpConnection); r5h}o)J  
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byte[] b = new byte[1024]; Ol1[o  
int nRead; 0tv"tA;  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) "rOe J~4 X  
{ SCs@Q  
nStartPos += fileAccessI.write(b,0,nRead); >!MOgLO3  
//if(nThreadID == 1) >j5) MF{"  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); x*Y&s<  
} _]a8lr+_-  
'VcZ_m:  
{L5!_]6  
Utility.log("Thread " + nThreadID + " is over!"); D0Yl?LU3  
bDownOver = true; Z{s&myd  
//nPos = fileAccessI.write (b,0,nRead); [`nY/g:  
} u@tJu'X  
catch(Exception e){e.printStackTrace ();} 6!bp;iLKy  
} mr dG-t(k  
} /. GHR  
3e4; '5q;  
,_@C(O  
//打印回应的头信息 99w;Q 2k  
public void logResponseHead(HttpURLConnection con) _xT=AF9~o  
{ "| 0g 1rd  
for(int i=1;;i++) ?K%&N99c!  
{ V#["Z}  
String header=con.getHeaderFieldKey(i); \g<9_  
if(header!=null) xP%`QTl\  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ~SgW+sDFu  
Utility.log(header+" : "+con.getHeaderField(header)); ]L#6'|W  
else hfT HP  
break; c`}-i6  
} /nEt%YYh;x  
} P=PcO>  
~nJcHJ1nb4  
Tap=K|b ]  
public void splitterStop() D-\WS^#  
{ ,_;+H*H>
"  
bStop = true; os6p1"_\f  
} d\Cx(Lb[  
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} 5N "fD{v{  
0!X;C!v;  
>^}nk04  
/* -;pZC}Nd3  
**FileAccess.java #eSVFD5ZU  
*//文件访问(定位，写) ^2Sa_.  
package NetFox; <Y~?G:v6+  
import java.io.*; lg` Qi&  
%\6ns  
#;FHyKx  
public class FileAccessI implements Serializable{ tYV%izE  
n5CjwLgu\b  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 M`IiK+IoU  
RandomAccessFile oSavedFile; U:6 J~  
long nPos; z d 9Gi5&  
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public FileAccessI() throws IOException -L e:%q2  
{ YT!QY@qw  
this("",0); _22;hnG<iy  
} XQC
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public FileAccessI(String sName,long nPos) throws IOException R^zTgyr  
{ @Dc?fyY*o<  
oSavedFile = new RandomAccessFile(sName,"rw"); `L<f15][  
this.nPos = nPos; `:W
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oSavedFile.seek(nPos); Cb}hE ro  
} 9^l[d<  
I)$`@.  
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public synchronized int write(byte[] b,int nStart,int nLen) {SH+lX0]{  
{ dhl[JC~ _  
int n = -1; W[S4s/)mg  
try{ NJJsg^'  
oSavedFile.write(b,nStart,nLen); 0l#{7^e  
n = nLen; Qx,?v|Xg  
} Jej P91  
catch(IOException e) \(UEjlo  
{ :`BZ,j_  
e.printStackTrace (); =XWew*  
} hpJ[VKe  
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9( ;lcOz  
return n; Id8^6FLw  
} 4-^LC<}k  
|RT#ZMJek  
G=4Da~<ij  
} j^A0[:2  
y7M"Dr%t^  
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/* ,ry2J,IT7  
**SiteInfoBean.java .S/W_R  
*/ l'YpSO~l7  
package NetFox; 3\eb:-B:@  
?8wFT!J  
]>h2h?2te  
public class SiteInfoBean { \ B 0xL,o<  
u?[P@_i<  
k,0RpE  
private String sSiteURL; //Site's URL I^
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private String sFilePath; //Saved File's Path /$zYSP)YT  
private String sFileName; //Saved File's Name Zcd!y9]#  
private int nSplitter; //Count of Splited Downloading File =!3G,qV  
-05zcIVo  
!Dp4uE:Pq  
public SiteInfoBean() $x;wnXXXM  
{//nSplitter的缺省值为5 ~X;r}l=k<  
//default value of nSplitter is 5 NC::;e  
this("","","",5); `WF?87l1  
} SZJ~ktXC-V  
mMO:m8W  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ) ^PY-~o[  
{ }8 A]  
sSiteURL= sURL; Er} xB~<t  
sFilePath = sPath; !]qwRB$5  
sFileName = sName; K'N`rx.7  
this.nSplitter = nSpiltter; qNER 6  
>69xl^Gd  
p"ht|x  
} ZQND^a:  
w#k'RuOw5  
$A6'YgK  
public String getSSiteURL() M5 ep\^  
{ hfP}+on%  
return sSiteURL; VkFTIyt  
} l){l*~5zl2  
]qL#/ 
 
->&AJI0  
public void setSSiteURL(String value) LKY4rY!|@d  
{ 2;.7c+r0  
sSiteURL = value; D8slSX`6j  
} 6d"dJV.\  
6grJoim|  
PH97O`"  
public String getSFilePath() iOm1U_S  
{ 3nf+imAF  
return sFilePath; mIq6\c$  
} 0wXfu"E{  
OM{-^  
i%>]$*  
public void setSFilePath(String value) 3(%hHM7DM  
{ 9a2Ga
 
sFilePath = value; s@ m A\  
}
(:].?o  
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+SkD/"5ng  
public String getSFileName() %yJL-6U  
{ l*("[?>I  
return sFileName; BIDmZU9tL  
} //`heFuc]>  
g"
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public void setSFileName(String value) +[`
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{ D|9C|
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sFileName = value; g}|a-  
} =|S8.|r+  
rX%#Q\
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:+ @-F>Q  
public int getNSplitter() 3lhXD_Y  
{ q`E6hm  
return nSplitter; HcUiv
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} ?+D_*'65D  
@jN!j*Y H  
X&MO}  
public void setNSplitter(int nCount) !;pmql  
{ %Ub"V\1  
nSplitter = nCount; ly%$>BRU  
} idvEE
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} pnca+d  
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EyI 9$@4  
/* y7wy9+>l  
**Utility.java WTA0S}pT  
*/ *W y0hnr;]  
package NetFox; VvSD&r^qI  
g?A4C`l6iy  
PkF B.  
public class Utility { pwT|T;j*  
^TVy:5Ag  
8xDSeXh;  
public Utility() ?'P8H^K6u  
{ r-^
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i cQsA  
g % q7  
} z[0L?~$  
0fxA*]h  
//线程睡眠 :(} {uG  
public static void sleep(int nSecond) m=z-}T5y!T  
{ !lm^(SSv  
try{ _:+W0YS  
Thread.sleep(nSecond); =\J^_g4-l  
} vpvPRwJ  
catch(Exception e) <'v?WV_  
{ D}HW7Hnu^  
e.printStackTrace (); ']u w,b  
} j8M}
*1  
} /(BQzCP9O;  
w?Nvm?_]  
//日志 t#&^ -;  
public static void log(String sMsg) @Q!f^  
{ *^=`HE89S  
System.err.println(sMsg); 6JmS9ho  
} zbddn4bW9  
mdypZ1f_  
r|fJ~0z  
public static void log(int sMsg) p!AQ
  
{ ZajQ B  
System.err.println(sMsg); UB|Nx(V s  
} `dMOBYV  
} M< *5Y43  
t.j q]L  
isj<lnQ  
/* xh#ef=Bw  
**TestMethod.java P{)&#HXUVb  
*/ 8|dlt$  
package NetFox; NJz8ANpro$  
b}9K"GT  
U/&?rY^|  
public class TestMethod { 4_&$isq  
.7g^w+W  
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public TestMethod() %HL@O]ftS  
{ ///xx/weblogic60b2_win.exe #fG!dD42  
try{ m589C+7  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); :?RooJ~#  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Fng":28o  
SiteFileFetch fileFetch = new SiteFileFetch(bean); [bJ"*^M)  
fileFetch.start(); '@AK0No\W  
} gD
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catch(Exception e){e.printStackTrace ();} EqUiC*u8{I  
.<u<!fL2  
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} "2'nLQ""q  
y:iE'SRRK6  
A8e b{
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public static void main(String[] args) _Y|k \|'  
{ Nq9Qsia&  
new TestMethod(); w{F8]N>0<  
} @-kzSm  
} 6b-d#H/1Y  
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