http断点续传简单实现（java)

/* f@,hO5h(_|  
**SiteFileFetch.java * wQZ'  
*/
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package NetFox; ; HR\R  
import java.io.*; TZ`]#^kU  
import java.net.*; 1.ugXD  
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public class SiteFileFetch extends Thread { :&\E\9  
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SiteInfoBean siteInfoBean = null; //文件信息Bean Kuzy&NI^w  
long[] nStartPos; //开始位置 2#Q"@  
long[] nEndPos; //结束位置 XEe+&VQmY  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 SFm.<^6  
long nFileLength; //文件长度 BLYk <m  
boolean bFirst = true; //是否第一次取文件 (p#;6Xhf  
boolean bStop = false; //停止标志 &*?!*+!,i  
File tmpFile; //文件下载的临时信息 Vq;{+j(  
DataOutputStream output; //输出到文件的输出流 IhFw{=2*  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） PPIG?fK)  
public SiteFileFetch(SiteInfoBean bean) throws IOException 83O^e&Bt  
{ QKuc21  
siteInfoBean = bean; [^"(%{H  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Y-q,Ovf!  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); &VBD2_T  
if(tmpFile.exists ()) ~{]m8a/ `6  
{ @bVh?T0~F,  
bFirst = false; Wb
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read_nPos(); 1:~m)"?I_^  
} &,gryBN  
else 9zGKQ|X)  
{ oXZ@*   
nStartPos = new long[bean.getNSplitter()]; '| Q*~Lh  
nEndPos = new long[bean.getNSplitter()]; -|iA!w#31  
} ;V(}F!U\z  
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} w<^2h}5  
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public void run() "u$]q1S  
{ d'@H@  
//获得文件长度 TKs@?Q,J  
//分割文件 $S-;M0G x  
//实例FileSplitterFetch 'MM~~:  
//启动FileSplitterFetch线程 Jj _+YfIM  
//等待子线程返回 LRlk9:QD>  
try{ oDiv9jm  
if(bFirst) zyQEz#O  
{ ~$
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nFileLength = getFileSize(); O%h 97^%k  
if(nFileLength == -1) O5n]4)<  
{ l4.@YYzbp.  
System.err.println("File Length is not known!"); u2Z^iY  
} )RKhEm%Vr2  
else if(nFileLength == -2) Tqh Rs  
{ @^jLYu|W  
System.err.println("File is not access!"); gJfL$S'w  
} MvwJ(3  
else H;8]GE2n  
{ _=$!T;}lE  
for(int i=0;i<nStartPos.length;i++) p:n^c5  
{ 7^e}|l  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); XA^:n+Yo  
} ee?Mo`  
for(int i=0;i<nEndPos.length-1;i++) 0r&9AnnWu+  
{ *LQY6=H  
nEndPos = nStartPos[i+1]; bM_(`]&*  
} f9bz:_;W_  
nEndPos[nEndPos.length-1] = nFileLength; PSw+E';  
} DG FvRB  
} !d@`r1t  
%*; 8m'  
8WQ%rN={8  
//启动子线程 0cU^ue%  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; { qx,X.5$  
for(int i=0;i<nStartPos.length;i++) vrDRSc6_  
{ uzA'D~)P  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), *F&&rsb  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), <plR<iI.  
nStartPos,nEndPos,i); %dR./{txT  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 7
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fileSplitterFetch.start(); ~n 9DG>a  
} JNl+UH:.  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), / kGX 6hh  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ><7`$2Or  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", <Tu
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nEndPos = " + nFileLength); &4
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// fileSplitterFetch[nPos.length-1].start(); rl7Y
=*Dv  
JH;DVPX9z  
[SvwJIJJ  
//等待子线程结束 :_zKUv]  
//int count = 0; wpI4P:  
//是否结束while循环 8PS:yBkA|  
boolean breakWhile = false; ![tI(TPq  
c[7qnSH  
;~;St>?\R\  
while(!bStop) t1^96@m^  
{ *p!dd?
8  
write_nPos(); ~.PYS!" +  
Utility.sleep(500); 1ouTZ'c?  
breakWhile = true; FCPRg^=<!~  
c y$$}  
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for(int i=0;i<nStartPos.length;i++) Qd?P[xm  
{ uy{KV"%"^g  
if(!fileSplitterFetch.bDownOver) BI]t}7  
{ d`/{0:F  
breakWhile = false; ISmnZ@  
break; B)dynGF8i  
} N!,l4!M\N  
} 0k 8SDRWU  
if(breakWhile) /K<Nlxcm  
break; 0]~n8mB>  
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ja
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//count++; )^+$5OR\c  
//if(count>4) wP9C\W;  
// siteStop(); '5--eYG  
} *1n:  
IM/\t!*7  
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System.err.println("文件下载结束！"); d6VKUAk'7>  
} [PT_y3'%  
catch(Exception e){e.printStackTrace ();} Y# #J  
} ?`>yl4  
@\R)k(F  
elN3B91\6r  
//获得文件长度 ;Z*RCuwg  
public long getFileSize() );[`rXH_  
{ Su7?-vY  
int nFileLength = -1; SccU@3.X~  
try{ q.7CPm+  
URL url = new URL(siteInfoBean.getSSiteURL()); ?H`LrL/k  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); N\?iU8w=  
httpConnection.setRequestProperty("User-Agent","NetFox"); lI 8"o>-~  
^9nM)[/C?  
}!LYV  
int responseCode=httpConnection.getResponseCode(); l O^h)hrR  
if(responseCode>=400) slx^" BF^  
{ D
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processErrorCode(responseCode); jDoWSYu4tY  
return -2; //-2 represent access is error d<Di;5  
} PD?H5W3@  
/d4xHt5a  
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String sHeader; 9HE)!Col  
) l)5^7=W  
+uA<g`4  
for(int i=1;;i++) l;2bBx7vW  
{ Oq("E(z+f  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); +*dJddz  
//Utility.log(in.readLine()); DF~w20+  
sHeader=httpConnection.getHeaderFieldKey(i); ,y.0Cb0  
if(sHeader!=null)
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{ y^ :x2P  
if(sHeader.equals("Content-Length")) X DX_c@U  
{ P7o6B,9  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); V)`?J)  
break; 7mN?;X33  
} ft7wMi  
} .28*vkH%C=  
else k"Is.[I?^  
break; r,}Zc W+  
} V= _8G3  
} R Q8okA  
catch(IOException e){e.printStackTrace ();} /~yqZD<O  
catch(Exception e){e.printStackTrace ();} ";~#epPkX  
k5($b{  
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Utility.log(nFileLength); y8L:nnSj  
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return nFileLength; @MM|.# ~T  
} K!9=e7|P  
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N 8OPeY  
//保存下载信息（文件指针位置） 8,R]R=  
private void write_nPos() uC3$iY:_e  
{ Ymw
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try{ ?YS`?Rr  
output = new DataOutputStream(new FileOutputStream(tmpFile)); a'\`Mi@rb  
output.writeInt(nStartPos.length); Li'T{0)1)  
for(int i=0;i<nStartPos.length;i++) >GcFk&x  
{ YZk&'w  
// output.writeLong(nPos); zx!1jS  
output.writeLong(fileSplitterFetch.nStartPos); z}&<DYD  
output.writeLong(fileSplitterFetch.nEndPos); Frml'Vfq7  
} 
}bHpFe  
output.close(); KDhHp^IXQ  
} =_XcG!"  
catch(IOException e){e.printStackTrace ();} jfWIPN  
catch(Exception e){e.printStackTrace ();} ~vXul`x  
} J7xZo=@k  
BgRiJFa.d[  
+vuW9  
//读取保存的下载信息（文件指针位置） j]P|iL  
private void read_nPos() H5 -I}z  
{ k X-AC5]  
try{ jzV#%O{`  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Bm?Ku7}.  
int nCount = input.readInt(); %>bwpN  
nStartPos = new long[nCount]; 5 909O  
nEndPos = new long[nCount]; (lm/S_U$  
for(int i=0;i<nStartPos.length;i++) LgaJp_d>9*  
{ <(iOzn  
nStartPos = input.readLong(); Vg3&:g5 /  
nEndPos = input.readLong(); 1Zecl);O{  
} 9O)>>1}*S  
input.close(); oM VJ+#[x  
} KIS.4nt#d"  
catch(IOException e){e.printStackTrace ();} sPw(+m*C   
catch(Exception e){e.printStackTrace ();} Ns $PS\  
} DXiD>1(q  
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private void processErrorCode(int nErrorCode) ~)Z`Q  
{ -lp_~)j^  
System.err.println("Error Code : " + nErrorCode); .3!4@l\9C  
} XC$~!  
@Q^;qMy  
Jq!($PdA  
//停止文件下载 Y}6)jzBV  
public void siteStop() `7j,njCX.  
{ HT]ubw]rJ  
bStop = true; `MD/CFl4  
for(int i=0;i<nStartPos.length;i++) u2eqVrY  
fileSplitterFetch.splitterStop(); -
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)Ga6O2:  
} >"[u.1J_'I  
} fP|\1Y?CS  
//负责部分文件的抓取 8ah]D  
**FileSplitterFetch.java c~ SI"  
*/ h(L5MZs  
package NetFox; kel {9b=i  
*" )[Srbg  
)\(pDn$W  
import java.io.*; kr?|>6?  
import java.net.*; V6k9L*VP  
c>g%oE  
#59zv=  
public class FileSplitterFetch extends Thread { H,}?YW  
I?"5i8E  
8n)Q^z+ K  
String sURL; //File URL $enh45Wy  
long nStartPos; //File Snippet Start Position ,&-[$,  
long nEndPos; //File Snippet End Position -%.V0
=G(Z  
int nThreadID; //Thread's ID Ir'f((8:  
boolean bDownOver = false; //Downing is over a|NU)mgEI  
boolean bStop = false; //Stop identical vpDs5tUl  
FileAccessI fileAccessI = null; //File Access interface 55,-1tWs  
ry0 =N^  
cF2/}m]  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException N[-)c,O  
{ |>4{4  
this.sURL = sURL; =m:W  
this.nStartPos = nStart; K="+2]{I  
this.nEndPos = nEnd; m5Kx}H~  
nThreadID = id; wLbngO=VG  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 =S,<yQJ  
} u W T[6R  
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public void run() 5b,98Q  
{ $b} +5  
while(nStartPos < nEndPos && !bStop) In&vh9Lw  
{ 9:o3JGHSc  
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8H?AL RG  
try{ V{{x~Q9  
URL url = new URL(sURL); 3iw9jhK!W  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection ();  ZsZ1  
httpConnection.setRequestProperty("User-Agent","NetFox"); Fev3CV$  
String sProperty = "bytes="+nStartPos+"-"; =6&D4~R  
httpConnection.setRequestProperty("RANGE",sProperty); DlI5} Jh  
Utility.log(sProperty); ]6 wi  
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3G^Ed)JvE  
InputStream input = httpConnection.getInputStream(); |T*qAJ8c  
//logResponseHead(httpConnection); Sj?sw]3  
<
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#LJ-IDuF!  
byte[] b = new byte[1024]; 'OCo1|iK~  
int nRead; 3:1 c_  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) b_yXM  
{ Q
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nStartPos += fileAccessI.write(b,0,nRead); oE1]vX  
//if(nThreadID == 1) D5u"4\g<&  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); (}1f]$V  
} -FV'%X$i  
u^%')Ncp  
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Utility.log("Thread " + nThreadID + " is over!"); RI3{>|*  
bDownOver = true; TZNgtR{q  
//nPos = fileAccessI.write (b,0,nRead); j9'XZq}  
} -i5g 8t'  
catch(Exception e){e.printStackTrace ();} Ag0_^  
} Gcz@ze  
} gecT*^  
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//打印回应的头信息 )=nPM`Jn.  
public void logResponseHead(HttpURLConnection con) )+4}Ix/q  
{ SoU'r]k1x  
for(int i=1;;i++) %W',cu  
{ \Rqh|T<D  
String header=con.getHeaderFieldKey(i); ."Ix#\|x  
if(header!=null) =GKYroNM  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); $1zeY6O  
Utility.log(header+" : "+con.getHeaderField(header)); XW_xNkpL5c  
else 9$V_=Bo  
break; a {$k<@Ww  
} iz>y u[|  
} pkfOM"5'  
*a,.E6C*  
7h9[-d6  
public void splitterStop() [S&O-b8A  
{ "Xk%3\{P  
bStop = true; roj04
|  
} G<-9U}~76  
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NU&^7[!yl  
} 4:eq{n  
1;kG[z=A  
ciGpluQF  
/* +>:_kE]?nX  
**FileAccess.java ?I2k6%a  
*//文件访问(定位，写) Q@W|GOH3  
package NetFox; Z:lB:U'o  
import java.io.*; fJ&<iD)6  
RTgA[O4J  
MpIw^a3(r  
public class FileAccessI implements Serializable{ 3Da,]w<  
WW[`E  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 e8ULf~I  
RandomAccessFile oSavedFile; T7lj39pJq  
long nPos; zJuRth)(,  
'/u:,ar  
3:~l2KIP4  
public FileAccessI() throws IOException 3$$5Mk(&  
{ hViprhC  
this("",0); s la*3~?*  
} L* khj3;  
%uz|NRB=  
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public FileAccessI(String sName,long nPos) throws IOException 4C,kA+P  
{ Sqdc1zC
 
oSavedFile = new RandomAccessFile(sName,"rw"); ;zZ,3pl-E  
this.nPos = nPos; o%Uu.P  
oSavedFile.seek(nPos); OAW=Pozr9  
} |.Nr.4Yp  
wuIsO;}/9  
-- i&"  
public synchronized int write(byte[] b,int nStart,int nLen) qab) 1ft  
{ Ws^+7u  
int n = -1; Mt[Bq6}ZD  
try{ om".j  
oSavedFile.write(b,nStart,nLen); u\()E|?p  
n = nLen; 8S.')<-f  
} ~A[YnJYA#  
catch(IOException e) 4Q$j]U&b  
{ 8^<c,!DM  
e.printStackTrace (); |'U,/
 
} kZU"Xn  
~@[(N]=q  
->&BcPLn  
return n; E6'8Zb  
} ERp:EZ'  
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} j}|N^A_ S  
&Q'\
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YH<$ +U  
/* VFilF<jvu  
**SiteInfoBean.java V.K70)]  
*/ F3r S6_  
package NetFox; a
);O3N/*I  
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((-aC`  
public class SiteInfoBean { H<V+d^qX\w  
DapQ}2'_  

!(W[!%  
private String sSiteURL; //Site's URL vx04h~  
private String sFilePath; //Saved File's Path t*o7,  
private String sFileName; //Saved File's Name NlA*\vco  
private int nSplitter; //Count of Splited Downloading File !?BW_vY  
f|X[gL,B  
*w=z~Jq^R"  
public SiteInfoBean() u
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{//nSplitter的缺省值为5 rQ=xcn[A  
//default value of nSplitter is 5 5XzrS-I+X@  
this("","","",5); `ajx hp  
} '/Cg*o/  
uP
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_mw13jcN]  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) !-KCFMvT  
{ 2y^U
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sSiteURL= sURL; ah 4kA LO  
sFilePath = sPath; zs4>/9O  
sFileName = sName; u06tDJ[  
this.nSplitter = nSpiltter; !K!)S^^Po?  
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et@">D%;]  
} .H ,pO#{;  
Z#CxQ D%\  
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public String getSSiteURL() <BZ_ (H  
{ %=y;L:S\p  
return sSiteURL; F@g17aa  
} P=2wkzeJj  
]Fxku<z7|  
9p5= _  
public void setSSiteURL(String value) gRHtgR)T3  
{ hMv2"V-X  
sSiteURL = value; '[%jjUU  
} Jl\'V
  
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87pnSj/X"  
public String getSFilePath() YDW|-HIF  
{ 5~QhX22  
return sFilePath; TM)u?t+[  
} WXLK89ev\  
TopHE  
3+e4e  
public void setSFilePath(String value) C1tb`  
{ Sg_O?.r  
sFilePath = value; 0',[J  
} (nq^\ZdF  
+N7"EROc  
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public String getSFileName() C\OECVT  
{ c+~LpSQ  
return sFileName; #,TELzUVE  
} qIz}$%!A  
zz&vfO31J  
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public void setSFileName(String value) ;I+H>$%jZ  
{ "-P/jk  
sFileName = value; Je 31".  
} ?,>5[Ha^?  
zSKKr?{  
-R:X<eb  
public int getNSplitter() ] opto  
{ IkQe~;Y  
return nSplitter; Kr]z]4.d@  
} I>aGp|4  
z+ ZG1\  
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public void setNSplitter(int nCount) WFem#hq  
{ I|T7+{
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nSplitter = nCount; AuXs B  
} j;+["mi  
} j`9Qzi1  
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*QE"K2\5  
/* 1x{kl01m%  
**Utility.java 7&foEJ3q  
*/ ~)?|J  
package NetFox; K{2h9 ]VF  
,56;4)cv  
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public class Utility { i
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public Utility() =) }nLS3t  
{
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n"Z |e tZ4  
*)D1!R<\,R  
} RG1\=J$:E  
O|e}   
//线程睡眠 m#n]Wgp'  
public static void sleep(int nSecond) x<>YUw8`  
{ d.AC%&W  
try{ 7&|6KN}c  
Thread.sleep(nSecond); v2>Z^  
} QC7k~I8  
catch(Exception e) 12OlrU  
{ oY.\)eJ~>  
e.printStackTrace (); 4Jykos2  
} 3{RL \gh$"  
} !8/gL  
+zp0" ,2B  
//日志 6bL~6-h%)  
public static void log(String sMsg) W.[BPR  
{ !_x*m
@/  
System.err.println(sMsg); s)w9%  
} X"<|Z]w  
Ep ">v>"  
{7X~!e|w  
public static void log(int sMsg) IU9, (E  
{ 1~Mn'O%  
System.err.println(sMsg); ;?~ 9hN!  
} "% Y u wMY  
} "b%F
mM  
A*i_|]Q  
*eGM7o*\X  
/* h(N=V|0  
**TestMethod.java M-Sv1ZLh  
*/ '5rUe\k  
package NetFox; yL&/m~{s  
;k}H(QI  
c<jB6|.=2  
public class TestMethod { E{>`MNj  
q-IWRb0j%a  
F1c&0*_A  
public TestMethod() Xw^X&Pp  
{ ///xx/weblogic60b2_win.exe c#pj:f*H  
try{ 1JeJxzv>C  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); o, LK[Q  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); <'2u a  
SiteFileFetch fileFetch = new SiteFileFetch(bean); x+:zq<0|  
fileFetch.start(); #U@| J}a  
} zYr z08PJ  
catch(Exception e){e.printStackTrace ();} qjLo&2)  
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xa#gWIP*  
} ;BVDt  
I
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g+|Bf&_  
public static void main(String[] args) &t6Tcy  
{ 9v~5qv;  
new TestMethod(); oMc1:=EG  
} %nQmFIt  
} M/B/b<['  
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