http断点续传简单实现（java)

/* p~8~EQFj  
**SiteFileFetch.java ,dVCbAS@  
*/ (la<X<w  
package NetFox; sx]?^KR:  
import java.io.*; uTl:u  
import java.net.*; /kw4":{]  
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public class SiteFileFetch extends Thread { W77JXD93  
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SiteInfoBean siteInfoBean = null; //文件信息Bean
l*v([@A\  
long[] nStartPos; //开始位置 3~cOQ%#]4  
long[] nEndPos; //结束位置 7Ck;LF}>0  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 =\XAD+
 
long nFileLength; //文件长度 'oT}jI
 
boolean bFirst = true; //是否第一次取文件 d:pp,N~2o  
boolean bStop = false; //停止标志 h.?[1hT4R  
File tmpFile; //文件下载的临时信息 G0Wd"AV+  
DataOutputStream output; //输出到文件的输出流 zl: u@!'  
\B}W(^\wg;  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） c<D
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public SiteFileFetch(SiteInfoBean bean) throws IOException Ra{B8)Q  
{ k oHY AF  
siteInfoBean = bean; @\"*Z&]8z0  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); chd${ j  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); _O!D*=I  
if(tmpFile.exists ()) >}4]51s  
{ Q}=RG//0*  
bFirst = false; 3Aj_,&X.@(  
read_nPos(); Ro<!n>
H  
} eGTK^p  
else |iwTzlt*#  
{ g$ 2M|Q  
nStartPos = new long[bean.getNSplitter()]; /vPb
 
nEndPos = new long[bean.getNSplitter()]; Iyc')\W&  
} -:~`g*3#  
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#>- rKv.A  
} dt \O7Rjw8  
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public void run() W^Rb~b^?  
{ 9~; Ju^b  
//获得文件长度 H]-W$V   
//分割文件 ?s?uoZ /2  
//实例FileSplitterFetch QE#$bCw  
//启动FileSplitterFetch线程 J<BdIKCma  
//等待子线程返回 \ yOZ&qU  
try{ 4O`h%`M  
if(bFirst) z5vryhX_Z  
{ EmUxM_T/2  
nFileLength = getFileSize(); {``}TsN  
if(nFileLength == -1) ?+|tPjg$  
{ U3V<ITZI8t  
System.err.println("File Length is not known!"); 6)3eB{$;  
} =#^dG''*"  
else if(nFileLength == -2) L|Ydd!m  
{ sN g"JQ  
System.err.println("File is not access!"); ZH}NlEn  
} A;|DQR()  
else uLCU3nI  
{ u!-eP7;7  
for(int i=0;i<nStartPos.length;i++) 0*AlLwO  
{ ZF t^q/pw  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); r{TNPa6!  
} ,9pi9\S  
for(int i=0;i<nEndPos.length-1;i++) v8@dvT<  
{ ?oJ~3Kg  
nEndPos = nStartPos[i+1]; 5&kR1Bp#-  
} # R&[+1=9j  
nEndPos[nEndPos.length-1] = nFileLength;  vXvV5Oq  
} .Ep3~9TBW  
} -J30g\  
FGH>;H@  
M/DTD98'N  
//启动子线程 :3t])mL#   
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; >ahj|pm  
for(int i=0;i<nStartPos.length;i++) j41:]6  
{ z K(5&u  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), NN:TT\!v  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ;MMFF{  
nStartPos,nEndPos,i); <
/=PN1=A  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); c[y8"M5  
fileSplitterFetch.start(); U .Od  
} bGJUu#  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 5QSmim  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); @j (jOe  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", :kVV.a#g  
nEndPos = " + nFileLength); nGbrWu]w  
// fileSplitterFetch[nPos.length-1].start(); sy?>e*-{  
!kcg#+s91  
B1M/5cr.  
//等待子线程结束 FSmi.7  
//int count = 0; Za6oYM_z  
//是否结束while循环 Hj\~sR$L-  
boolean breakWhile = false; z3C^L  
ul?BKV+3E  
#~+#72+x7  
while(!bStop) asi1c y\  
{ X]fw9tZ  
write_nPos(); u
J
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Utility.sleep(500); S8=4C`>jf  
breakWhile = true; k:TfE6JZ  
SRTpE,  
8Vn6* Xn  
for(int i=0;i<nStartPos.length;i++) }$)<k
 
{ ?R(3O1,v^  
if(!fileSplitterFetch.bDownOver) :#/bA&  
{ 5);#\&B  
breakWhile = false; JqUVGEg  
break; e%U*~{m+  
} nB5[]x'  
} *lK4yI*%o  
if(breakWhile) 4BT`|(7  
break; 2mUu3fZ  
_}&]`,s>  
hNle;&*F  
//count++; JB+pFBeY  
//if(count>4) nnG2z@$-  
// siteStop(); ?6QJP|kE  
} hwzUCh 5!  
g#4gGhI  
iy]}1((hR  
System.err.println("文件下载结束！"); $3TTHS o  
} !I[n|r"  
catch(Exception e){e.printStackTrace ();} 7fay:_  
} 32iI :u  
JF*g!sV%  
f}X8|GlBo  
//获得文件长度 m-89nOls  
public long getFileSize() .A\\v6@  
{ xp&!Cl>C3\  
int nFileLength = -1; @?m8/t9.  
try{ mr!I}I7x&x  
URL url = new URL(siteInfoBean.getSSiteURL()); \.c )^QQ  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Hg`{9v  
httpConnection.setRequestProperty("User-Agent","NetFox"); mM}Ukmy  
|T_Pz&-  
@vYmkF`  
int responseCode=httpConnection.getResponseCode(); YfwJBzD  
if(responseCode>=400) 0s|LK  
{ Qs9U&*L  
processErrorCode(responseCode); rk/ c  
return -2; //-2 represent access is error X u):.0I  
} dz|*n'd  
$NT9LtT@K  
!Blk=L+p  
String sHeader; o#xg:m_py  
;a&:r7]=  
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for(int i=1;;i++) (AG  
{ r^t{Ii~  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); DME?kh>7  
//Utility.log(in.readLine()); X-1Vp_(,TP  
sHeader=httpConnection.getHeaderFieldKey(i); qb4;l\SfT  
if(sHeader!=null) $Je"z]cy-  
{ -FN6sNvIh  
if(sHeader.equals("Content-Length")) 'd^gRH<z  
{ 9JV 3  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); EQJ_$6
  
break; "O[76}I+.q  
} ^<\} Y  
} h.$__Gs  
else ky[Xf -9#  
break; .crM!{<Y  
} kc'0NE4oq  
} %Z[/U  
catch(IOException e){e.printStackTrace ();} \TB%N1^  
catch(Exception e){e.printStackTrace ();} 5^K#Tj ;2  
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Utility.log(nFileLength); r?nV Sb|[  
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'ZH<g8:=@  
return nFileLength; (kQ.tsl  
} (+LR u1z  
0BB@E(*  
6 2`PK+  
//保存下载信息（文件指针位置） NWHH.1|  
private void write_nPos() yVI;s|jG  
{ tOg 8L2  
try{ DRW.NL o  
output = new DataOutputStream(new FileOutputStream(tmpFile)); i!W8Q$V  
output.writeInt(nStartPos.length); S@xsAib0J  
for(int i=0;i<nStartPos.length;i++) z|]oM#Gt  
{ !mxh]x<e  
// output.writeLong(nPos); o9LD6$  
output.writeLong(fileSplitterFetch.nStartPos); %<C G|]W  
output.writeLong(fileSplitterFetch.nEndPos); F|Dz]ar  
} ]jVSsSv  
output.close(); pOVghllO  
} zrU$SWU  
catch(IOException e){e.printStackTrace ();} .Spi$>v  
catch(Exception e){e.printStackTrace ();} QHzX 5$IM  
} .x!7  
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//读取保存的下载信息（文件指针位置） nqxq@.L2  
private void read_nPos() BgWz<k}5M  
{ sRyw\v-=P  
try{ PyT}}UKj:  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); "
56?/ jF  
int nCount = input.readInt(); +Bq}>  
nStartPos = new long[nCount]; gLaO#cQ%  
nEndPos = new long[nCount]; jqGo-C~  
for(int i=0;i<nStartPos.length;i++) 0"
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{ aT1CpY=T|.  
nStartPos = input.readLong(); ah/6;,T  
nEndPos = input.readLong(); UI<PNQvo9  
} nE,gQHw  
input.close(); 6Sb'Otw.  
} bj7MzlGFy  
catch(IOException e){e.printStackTrace ();} ]EM)_:tRf  
catch(Exception e){e.printStackTrace ();} UiK+c30FU  
} *lerPY3 q  
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private void processErrorCode(int nErrorCode) c_z/At;4  
{ {|5$1v  
System.err.println("Error Code : " + nErrorCode); ?]\W8)  
} Vr-3M+l=O  
L`\`NNQC  
*mQDS.'AB@  
//停止文件下载 RC8)f8n  
public void siteStop() QFNz9c  
{ ^?6 W<  
bStop = true; t$y&=v  
for(int i=0;i<nStartPos.length;i++) q3x;_y^  
fileSplitterFetch.splitterStop(); Q}Ze-JIL$  
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.hQ3A"  
} =tf@4_  
} [)H,zpl  
//负责部分文件的抓取 11B{gUv.]  
**FileSplitterFetch.java Y-%l7GErhL  
*/ mF
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package NetFox; /h7>Z9T  
6t_ 3%{  

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import java.io.*; uq|vNLW26  
import java.net.*; Lov.E3S6;  
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public class FileSplitterFetch extends Thread { n~,]KdU]  
8sR  
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String sURL; //File URL Zr.\`mG4f  
long nStartPos; //File Snippet Start Position h{W$ fZc<  
long nEndPos; //File Snippet End Position } T/}0W]0  
int nThreadID; //Thread's ID (RDa,
&  
boolean bDownOver = false; //Downing is over rysP)e  
boolean bStop = false; //Stop identical )e|$K= D  
FileAccessI fileAccessI = null; //File Access interface [GR|$/(z=  
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+H[}T ]  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException s`Yu"s 8}4  
{ iJ`%yg,  
this.sURL = sURL; v7o?GQ75  
this.nStartPos = nStart; >J^7}J  
this.nEndPos = nEnd; *`+<x  
nThreadID = id; ;!l*7}5X=  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 #gX%X~w$F  
} vz;7} Zj]  
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a%Z4_ToLZ  
public void run() IS,zy+w  
{ DnNt@e2|  
while(nStartPos < nEndPos && !bStop) Hi; K"H]x1  
{ OX)#F'Sl}  
#MhNdH#  
< v|%K.yd  
try{ |t4Gz1"q=8  
URL url = new URL(sURL); Tn4W\?R  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); $z2xZqe  
httpConnection.setRequestProperty("User-Agent","NetFox"); 9{)Z5%Kz  
String sProperty = "bytes="+nStartPos+"-"; c$,c`H(~  
httpConnection.setRequestProperty("RANGE",sProperty); [Krm .)  
Utility.log(sProperty); t4f (Y,v  
zB#_:(1qK  
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InputStream input = httpConnection.getInputStream(); BKE\SWu  
//logResponseHead(httpConnection); ~rgf{oGz  


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byte[] b = new byte[1024]; mP9cBLz  
int nRead; C1X}3bB  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) d9
8))G~W  
{ &Pu+(~'Q  
nStartPos += fileAccessI.write(b,0,nRead); b$dJ?%W  
//if(nThreadID == 1) 5nMkd/  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); |MTpU@`p5  
} ruZYehu1W  
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Utility.log("Thread " + nThreadID + " is over!"); V*6l6-y~Ih  
bDownOver = true; v2/yw,  
//nPos = fileAccessI.write (b,0,nRead); gHQPhe#n  
} TqS2!/jp  
catch(Exception e){e.printStackTrace ();} /hm84La  
} u:_sTfKm&  
} [NHg&R H  

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//打印回应的头信息 8g<Q5(  
public void logResponseHead(HttpURLConnection con) ?!bd!:(N  
{ vC)"*wYB{  
for(int i=1;;i++) X}zX`]:I'  
{ Pv< QjY  
String header=con.getHeaderFieldKey(i); M0cd-Dn  
if(header!=null) ~A^E  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); G;2R]H#p  
Utility.log(header+" : "+con.getHeaderField(header)); -Nsk}Rnk*  
else siZr@g!L  
break; C-Nuy1o  
} SV
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} TRF]i/Bs  
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public void splitterStop() r0)JUc}Fyq  
{ 8 ne/=N|,  
bStop = true; 1S+;ZMk  
} >F/XZ
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} 8{R&EijC  
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/* [dl+:P:zc  
**FileAccess.java Ee{`Y0  
*//文件访问(定位，写) i~9?:plS  
package NetFox; ETM2p1ru0  
import java.io.*; K@q&HV"'.  
qOW#Q:T  
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public class FileAccessI implements Serializable{ *%:@ cbF-M  
&svx@wW  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 RG&I\DTyt  
RandomAccessFile oSavedFile; }-d)ms!  
long nPos; #":: '?,  
fi=0{  
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public FileAccessI() throws IOException ^uia`sOP4  
{ a*D,*C5}  
this("",0); v9u<F6  
} ERF,tLa!  
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public FileAccessI(String sName,long nPos) throws IOException E_~x==cb  
{ Yg/}ghF\  
oSavedFile = new RandomAccessFile(sName,"rw"); q7|:^#{av  
this.nPos = nPos; J5;5-:N  
oSavedFile.seek(nPos); xZX`%f-  
} W
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@cZ\*,T  
fb23J|"  
public synchronized int write(byte[] b,int nStart,int nLen) t\zbEN  
{ 7skljw(  
int n = -1; ZT6V/MD7T.  
try{ 0x\2#i  
oSavedFile.write(b,nStart,nLen); 7!pLK&_  
n = nLen; (qUK7$  
} cQX:%Ix=  
catch(IOException e) }g>kpa0c  
{ Y=E9zUF  
e.printStackTrace (); Rv,82iEKs  
} qYK4)JP  
@M=$qO_$9  
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return n; (VyA6a8  
} T'.[F  
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} 3E,DipHg  
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\ZMP_UU(  
/* w
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**SiteInfoBean.java Cc!
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*/ s O=4IBE  
package NetFox; HMV)U
{  
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public class SiteInfoBean { T^]7R4Fg  
/YFa ;2 W  
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private String sSiteURL; //Site's URL qEQAn/&  
private String sFilePath; //Saved File's Path b,Ke>.m  
private String sFileName; //Saved File's Name Nt~x&s  
private int nSplitter; //Count of Splited Downloading File ^LVk5l)\>g  
Umz05*  
y@3Q;~l,  
public SiteInfoBean() ePEe?o4;  
{//nSplitter的缺省值为5 :m Kxa  
//default value of nSplitter is 5 paWxanSt  
this("","","",5); TGf;_)El  
} XFQNr`  
m;o4Fu  
($62o&I  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) *g_w I%l  
{ UW6VHA>  
sSiteURL= sURL; 26.)Ur<F  
sFilePath = sPath; e[{mVhg4E  
sFileName = sName; 'w.}2(  
this.nSplitter = nSpiltter; ,hWcytzEw  
=IZ[_ /@  
RBE7485  
} 4&{!M _  
&s8<6P
7  
#byJqy&e  
public String getSSiteURL() ?v4E<iXs  
{ K(VW%hV1  
return sSiteURL; d2~l4IL)~  
} XQ?fJWLU  
\GL*0NJ  
b+{r!D}~  
public void setSSiteURL(String value) \}#@9=  
{ Z5B/|{  
sSiteURL = value; mj2Pk,,SA  
} Nqcp1J"  
z)}!e,7  
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public String getSFilePath() ? %(spV  
{ CZ(`|;BC*  
return sFilePath; k!3 cq)  
} GoIQ>n
 
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. I==-|  
public void setSFilePath(String value) \uM? S  
{ sbnjy"Z%  
sFilePath = value; }pawIf4V  
} RlRs}yF  
3vW4<:Lgy  
:q (&$
 
public String getSFileName() ',)7GY/n~  
{ g^l RG3a  
return sFileName; Ur!~<4GO  
} eT[&L @l]b  
%>zjGF<
 
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public void setSFileName(String value)  hw=GR_,  
{ 89HsPB1"t  
sFileName = value; #jA)>z\Q^  
} ,j178
EX  
?djQZ*  
o
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public int getNSplitter() pRi<cO  
{ C6jR=@42Q  
return nSplitter; zN!j%T.e  
} +Gh7^v|"  
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public void setNSplitter(int nCount) (=c1  
{ N3%*7{X 9  
nSplitter = nCount; q0./O|Dj   
} .H~Y
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} 7\Fs=\2l+'  
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fS=hpL6]@  
/* O{]9hm(tN  
**Utility.java JOD/Raq.1k  
*/ 57Z-  
package NetFox; h`Tz5% n  
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(9C<K<  
public class Utility { Kat&U19YH  
7L3ik;>  
Y; ).+si  
public Utility() gl7|H&&xV  
{ Y)|N"f;  
.`p&ATgv  
{5j66QFoo  
} fex,z%}p  
-VT+O+9_A  
//线程睡眠 )L5i&UK.  
public static void sleep(int nSecond) X.FGBR7=q  
{ w>e s  
try{ igC_)C^i>  
Thread.sleep(nSecond); c#cx>wq9  
} k)7{Y9_No  
catch(Exception e) X}A'Cg0y  
{ V/%~F6e  
e.printStackTrace (); V diJ>d[  
} #FH[hRo=6  
} "r'ozf2\  
s?C&s|'.  
//日志 @xAfZb2E  
public static void log(String sMsg) z#6?8y2-  
{ ,d_Gn!  
System.err.println(sMsg); .iwZ*b{  
} & ,hr8  
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y~ rXl  
public static void log(int sMsg) DAO]uh{6  
{ %)(Cp-b!  
System.err.println(sMsg); 3n;K!L%zMT  
} K8I$]M  
} v]VWDT `  
1iBP,:>*  
jZ*WN|FK?  
/* rS8 w\`_  
**TestMethod.java ~O6\6$3b5E  
*/ nH-V{=
**  
package NetFox; $XnPwOj  
# Su~`]  
Zjh2{ :  
public class TestMethod { cr;`Tl~}s  
,5Vt]#F5@  
[1yq{n=  
public TestMethod() ;2xO`[#  
{ ///xx/weblogic60b2_win.exe R[B?C;+(O  
try{ 5*-3? <)e  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); gABr@>Vv  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); }^kL|qmjR  
SiteFileFetch fileFetch = new SiteFileFetch(bean); *m+BuGt|  
fileFetch.start(); \wvg,j=  
} +-?/e-z")  
catch(Exception e){e.printStackTrace ();} /
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} w n|]{Ww35  
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Vr.Y/3N&'  
public static void main(String[] args) dtt~ Bd  
{ cC{"<fYF  
new TestMethod(); 0%`4px4J  
} :mcYZPX#  
} D<$Xy
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