http断点续传简单实现（java)

/* UB(8N7_/  
**SiteFileFetch.java &,K;F'  
*/ ]Q)TqwYF  
package NetFox; 3EzI~Zsx  
import java.io.*; G%4vZPA  
import java.net.*; VoP(!.Ua>7  
i44KTC"sB  
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public class SiteFileFetch extends Thread { {qh`8  
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3 #jPQ[+  
SiteInfoBean siteInfoBean = null; //文件信息Bean "h)+fAT|,  
long[] nStartPos; //开始位置 tb_
}w@:kU  
long[] nEndPos; //结束位置 6%:'2;xM  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Ou,B3kuQ+  
long nFileLength; //文件长度 &Cdd  
boolean bFirst = true; //是否第一次取文件 67f#Z&r2k  
boolean bStop = false; //停止标志 mk[=3!J  
File tmpFile; //文件下载的临时信息 O0~[]3Y[=  
DataOutputStream output; //输出到文件的输出流 =I*"vwc?  
7eu7ie6  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） EI/_=.d  
public SiteFileFetch(SiteInfoBean bean) throws IOException ;,9|;)U?u  
{ 0WYVt"|;}c  
siteInfoBean = bean; _YbHnb  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); NEK;'"~  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); v|n.AGn  
if(tmpFile.exists ()) OZ7MpQ  
{ ~omX(kPzK  
bFirst = false; ^yBx.GrQc  
read_nPos(); R=PjLH&)  
} i%-c/ lop  
else AMtFOXx%I  
{ 33 N5>}  
nStartPos = new long[bean.getNSplitter()]; TNiFl hq  
nEndPos = new long[bean.getNSplitter()]; F1MPo;e  
}  BeP0lZ  
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} )%UO@4  
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public void run() N!H
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{ 'm-s8]-W  
//获得文件长度 a*??!  
//分割文件 LoNz 1KJL  
//实例FileSplitterFetch w'U;b  
//启动FileSplitterFetch线程 O^`Y>>a  
//等待子线程返回 ~2=B:;  
try{ IWKQU/l!  
if(bFirst) 9I.="b=J)  
{ ]k>S0  
nFileLength = getFileSize(); [?]s((A~B  
if(nFileLength == -1) _L&C4 <e'  
{ Q2iu}~  
System.err.println("File Length is not known!"); {t9'8
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} "z7.i{  
else if(nFileLength == -2) <!4'?K-N  
{ T;.#=h  
System.err.println("File is not access!"); +vZ-o{}.jO  
} -_A0<A.  
else LD#]"k  
{ *Q5/d9B8TN  
for(int i=0;i<nStartPos.length;i++) l"O=xt`m{  
{ ~hz]x^:  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); N"FQMxqm  
} &K|CH? D  
for(int i=0;i<nEndPos.length-1;i++) Qs</.PO  
{ opdi5e)jK  
nEndPos = nStartPos[i+1];
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} IDwneFO  
nEndPos[nEndPos.length-1] = nFileLength; QiB:K Pz[  
} i wK,XnIR  
} K]Ed-Tz8QZ  
YHg4WW$  
C#vU'RNpl  
//启动子线程 kg9ZSkJr  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; |P~TZ  
for(int i=0;i<nStartPos.length;i++) Z>M0[DJ_  
{ 8CwgV  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), F8/4PB8-  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Q>= :$I  
nStartPos,nEndPos,i); 8"RX~Igf  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); APy&~`  
fileSplitterFetch.start(); h<.&,6R  
} M%yT?R+  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), :C>slxY  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); D0tI
  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 1^Ci$ra  
nEndPos = " + nFileLength); E3sl"d;~  
// fileSplitterFetch[nPos.length-1].start(); X_O(j!h  
i>>_S&!9p  
A"i40 @+  
//等待子线程结束 XeJx/'9o{  
//int count = 0; "J7=3$CA  
//是否结束while循环
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boolean breakWhile = false; YzsHec  
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OG/R6k.  
while(!bStop) $)z(4Ev  
{ 
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write_nPos(); W 4~a`D7  
Utility.sleep(500); n
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breakWhile = true; ,Q2`N{f  
.kGg}  
<.+hV4,3  
for(int i=0;i<nStartPos.length;i++) M|7xI  
{ FL"7u2rh,  
if(!fileSplitterFetch.bDownOver) "J3@Z,qW  
{ oB#KR1 >%7  
breakWhile = false; ^Jsx^?  
break; jt=mK,%  
} r1JKTuuo
 
} 1i^
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if(breakWhile) 
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break; XwE(&ZCf'b  
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{3@/@jO?  
//count++; Gpo(Zf?  
//if(count>4) $hn#T#J3  
// siteStop(); &mp=jGR  
} ebp18_a|  
ixp(^>ZN  
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System.err.println("文件下载结束！"); )lBke*j~  
} .Hc]?R]  
catch(Exception e){e.printStackTrace ();} +Ae4LeVzc  
} N'=8Dj  
#1&wfI$  
2LEf"FH0~  
//获得文件长度 MG<F.u  
public long getFileSize() /87?U; |V  
{ 7[.aAGTZ;  
int nFileLength = -1; }&bO;o&>  
try{ 5@F1E8T  
URL url = new URL(siteInfoBean.getSSiteURL()); z~UqA1r  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); &X }GJLC3  
httpConnection.setRequestProperty("User-Agent","NetFox"); Mx4 <F "9  
4&&((H  
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int responseCode=httpConnection.getResponseCode(); n2Q~fx<6%  
if(responseCode>=400) CcG{+-=H)  
{ v&(PM{3o  
processErrorCode(responseCode); 71Q-_Hi  
return -2; //-2 represent access is error DUFfk6#X}  
} +pkX$yz  
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mr,IP=e~  
String sHeader; ncuqo'r  
Q~MV0<{  
h2QoBGL5  
for(int i=1;;i++) @6~r7/WD  
{ +Vl\lL -  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); :&S6AP  
//Utility.log(in.readLine()); Cd?aC  
sHeader=httpConnection.getHeaderFieldKey(i); |$f.Qs~?  
if(sHeader!=null) 9o@5:.b<j  
{ /xUTm=w7u  
if(sHeader.equals("Content-Length")) {U=Mfo?AH  
{ D C{l.a.  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); b MZ-{<+i  
break; ]4^9Tw6 _b  
} wrSw>sE"  
} S8(Y+jgk;a  
else g\[?U9qN  
break; ABuK`(f.  
} R7+3$F5B  
} 2? 9*V19yu  
catch(IOException e){e.printStackTrace ();} LZG?M|(6D  
catch(Exception e){e.printStackTrace ();} _lcx?IV  
^`XQ>-wWue  
V^sZXdDNL  
Utility.log(nFileLength); e`27 ?  
qb'4x){  
Ha>Hb`  
return nFileLength; Ka%u#};  
} gY9HEfB  
&FHzd/  
8b\XC%k  
//保存下载信息（文件指针位置） /@h)IuW  
private void write_nPos() `@!4#3H  
{ 5 Sm9m*/  
try{ GTgG0Ifeh  
output = new DataOutputStream(new FileOutputStream(tmpFile)); JVy-Y  
output.writeInt(nStartPos.length); I.As{0cc  
for(int i=0;i<nStartPos.length;i++) _V
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{ C^oj/}^  
// output.writeLong(nPos); v50w}w'  
output.writeLong(fileSplitterFetch.nStartPos); BC.~wNz6  
output.writeLong(fileSplitterFetch.nEndPos); R~TzZ(Ah]  
} )(V|d$n  
output.close(); .dM4B'OA?  
} "jS@ug  
catch(IOException e){e.printStackTrace ();} %xv }  
catch(Exception e){e.printStackTrace ();} j N":9+F  
} V9
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90<z*j$EK  
2%o@?Rp  
//读取保存的下载信息（文件指针位置） b/"&E'5-`\  
private void read_nPos() "V|&s/9  
{ i286 J.  
try{ mu`:@7+Yp  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); NNDW)@p6z  
int nCount = input.readInt(); }h{
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nStartPos = new long[nCount]; CNP!v\D  
nEndPos = new long[nCount]; b`:n i   
for(int i=0;i<nStartPos.length;i++) 4k%y*L  
{ jMFLd  
nStartPos = input.readLong(); G)5R iRcs  
nEndPos = input.readLong(); sKDsps^$  
} LkvR]^u0  
input.close(); &/wd_;d^A  
} &gGh%:`B  
catch(IOException e){e.printStackTrace ();} 0G?*i_u\  
catch(Exception e){e.printStackTrace ();} +h*-9  
} 55LW[Pc  
@s7ZfV??  
N(ov.l;  
private void processErrorCode(int nErrorCode) [9N
>*dKB  
{ !C]2:+z-MF  
System.err.println("Error Code : " + nErrorCode); 'Z;8-1M?O  
} :]]#X ~J  
X0\O3l*j  
5 1&||.  
//停止文件下载 olLVT<  
public void siteStop() Z@sDxYt9  
{ X"hdCY%  
bStop = true; pb8sx1.j;  
for(int i=0;i<nStartPos.length;i++) ' 5tk0A  
fileSplitterFetch.splitterStop(); q)N]*~  
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KAkD" (!  
} =Pj+^+UM  
} 4zo^ b0v  
//负责部分文件的抓取 #M/^n0E  
**FileSplitterFetch.java 76 ]X  
*/ P6G&3yPt  
package NetFox; #LU<v  
"|k 4<"]  
NAg9EaWja{  
import java.io.*; HgY [Q}7s  
import java.net.*; ,ICn]Pdz@  
2?c##Izn  
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public class FileSplitterFetch extends Thread { LZR x>q^  
.R";2f3  
~9ZW~z'  
String sURL; //File URL z.vERP56  
long nStartPos; //File Snippet Start Position Qvc$D{z  
long nEndPos; //File Snippet End Position 3fBV SFVS  
int nThreadID; //Thread's ID =(aA`:Nl  
boolean bDownOver = false; //Downing is over qz_'v{uAj  
boolean bStop = false; //Stop identical >v?&&FhHK<  
FileAccessI fileAccessI = null; //File Access interface "O (N=|b  

sd m4zV]&  
),!1B%  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException H\vd0DD;  
{ [uLwr$N<%L  
this.sURL = sURL; NP#6'eH\  
this.nStartPos = nStart; UgD|tuz]  
this.nEndPos = nEnd; 1U?,}w  
nThreadID = id; k.5(d.*(  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 uCB>".'kM  
} Ez)hArxns  
w ag^Sk  
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public void run() %$Smei
 
{ 5|<jPc  
while(nStartPos < nEndPos && !bStop) nY)H-u^  
{ 7$zeRYD+  
#Ch*a.tI@  
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try{ {3LAK[C  
URL url = new URL(sURL); [C-4*qOaa2  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); KHO@"+  
httpConnection.setRequestProperty("User-Agent","NetFox"); q}xYme4  
String sProperty = "bytes="+nStartPos+"-"; .Ld{QPa  
httpConnection.setRequestProperty("RANGE",sProperty); *"qS  
Utility.log(sProperty); 1-=ZIHW  
KkJrh@lk  
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/  
InputStream input = httpConnection.getInputStream(); *DUP$@}k  
//logResponseHead(httpConnection); =:"wU  
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byte[] b = new byte[1024]; %a\L^w)Xn  
int nRead; my]t[%Q{  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) WeiDg,]e$b  
{ |PNPOj0  
nStartPos += fileAccessI.write(b,0,nRead); E;MelK<8(  
//if(nThreadID == 1) })F.Tjf*  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); fw3P?_4;*  
} ]. E/s(p  
G4;5$YGG  
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Utility.log("Thread " + nThreadID + " is over!"); e0z(l/UB  
bDownOver = true; Q94Lq~?YF  
//nPos = fileAccessI.write (b,0,nRead); 2 ":W^P  
} 3 BQZ[%0@  
catch(Exception e){e.printStackTrace ();} ?se\?q  
} ks|c'XQb  
} JYw_Z*L=m  
b4?]/Uy+/  
^:cc3wt'3[  
//打印回应的头信息 "tF#]iQQ u  
public void logResponseHead(HttpURLConnection con) /?Y]wY  
{ |MMaaW^"  
for(int i=1;;i++) ;@<Rh^g]  
{
rNN,!  
String header=con.getHeaderFieldKey(i); 3YO%$  
if(header!=null) J\l'nqS"  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); [k<.BCE  
Utility.log(header+" : "+con.getHeaderField(header)); P _x(`H  
else 2 r';)8:  
break; =nff;Xu  
} {A`J0ol<B9  
} E (.~[-K4  
`k.0d`3(  
I83 _x|$FZ  
public void splitterStop() 5<$8.a#  
{ =9!|%j  
bStop = true; k-!Jww  
} `8lS)R!  
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>[0t@Tu,D  
} :\F1S:&P  
b!4Z~d0=  
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/* #V$h?`qhwr  
**FileAccess.java up!54}
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*//文件访问(定位，写) 8G )O,F7z  
package NetFox; snicVzvA  
import java.io.*; ^61;0   
wx*03(|j;  
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public class FileAccessI implements Serializable{ 6Z#$(oC  
G0Y]-*1  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 f\vMdY  
RandomAccessFile oSavedFile; b*)F7{/Z  
long nPos; 3EV?=R  
9<Ks2W.N  
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public FileAccessI() throws IOException mW=9WV  
{ eh;L])~C  
this("",0); 85:KlBe%+  
} +5x{|!Pn  
Y(&rlL(sPK  
eq(1'?7]`G  
public FileAccessI(String sName,long nPos) throws IOException :|%1i>O  
{ 8RA  
oSavedFile = new RandomAccessFile(sName,"rw"); -2B3 xIZJ  
this.nPos = nPos; _$KEE|9  
oSavedFile.seek(nPos); nrV!<nNBk  
} "F:V$,mJ  
1|dXbyUd  
N c(f+8  
public synchronized int write(byte[] b,int nStart,int nLen) \7PC2IsT3  
{ -&EU#Wqh  
int n = -1; A5E^1j}h@  
try{ P%a
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oSavedFile.write(b,nStart,nLen); ?*^HZ~O1  
n = nLen; 37b6w6{D  
} 5t,X;  
catch(IOException e) i`}!<
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{ WBWIHv{j  
e.printStackTrace (); 8?hZ5QvA(j  
} _0|@B8!J?  
4^Og9}bm  
Z+Cjg#+  
return n; _BoYyJQH  
} _<%YLv  
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w0X})&,{`m  
} FQ"ED:lks  
= N^Ec[u(l  
~gdnD4[G  
/* ?sv[vR(  
**SiteInfoBean.java .hRtQU  
*/ Dkg^B@5Xr  
package NetFox; M%Zh{  
A|(!\J0  
39~te%;C7  
public class SiteInfoBean { []G@l. ]W  
Q7]bUPDO  
GuC 9h^[=M  
private String sSiteURL; //Site's URL M5:j)oW  
private String sFilePath; //Saved File's Path ~ycWcZi>  
private String sFileName; //Saved File's Name 2f6BZ8H+Z  
private int nSplitter; //Count of Splited Downloading File BvS
!P8  
NJCSo(O  
&2nICAN[  
public SiteInfoBean() L[^.pO  
{//nSplitter的缺省值为5 y@(EGfI  
//default value of nSplitter is 5 /r8sL)D+  
this("","","",5); ^^g u  
} "R\D:Olb#  

,3 [FD9  
t?H sfN  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) mNlbiB  
{ TBZhL  
sSiteURL= sURL; @KRia{  
sFilePath = sPath; `CRF E5  
sFileName = sName; 0oe2X1.%  
this.nSplitter = nSpiltter; j;I(w [@P  
fohZ&f|>  
DzIV5FG  
} 1)3'Y2N*  
Wuk!\<T{  
$Wu|4]o>9  
public String getSSiteURL() EE*|#  
{ :31?Z(fQ  
return sSiteURL; .u'MMe>^  
} D&x
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8JXS:J.|v  
KGGnypx`  
public void setSSiteURL(String value) TR%8O;  
{ 7m%[$X`  
sSiteURL = value; J!}\v=Rn  
} ~iPXn1  
T7|=`~  
E#Ol{
6  
public String getSFilePath() "
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{ p,tkVedR  
return sFilePath; \E'z+0  
} 9 e|[9  
] &SmeTe  
?Yx2q_KZk  
public void setSFilePath(String value) !DUOi4I  
{ CM6! 1 7  
sFilePath = value; [{>3"XJ'  
} FOteNQTj  
1p$*N  
/l+"aKW 2  
public String getSFileName() :2V|(:^'  
{ 1,7 }ah_  
return sFileName; <rvM)EJv|  
} hkRqtpYK  
MdFFt:y:  
b`JS&E  
public void setSFileName(String value) v4K! BW  
{ WM%w_,Z  
sFileName = value; #xfav19{.  
} $KhD>4^jL  
RY3=UeoF  
+~|Jn_:A f  
public int getNSplitter() G.$KP  
{ fQ
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return nSplitter; e}n(mq  
} mmG]|Cl@  
F8#MI G   
 Vvp
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public void setNSplitter(int nCount) I2-ue 63 ?  
{ KEdqA/F>  
nSplitter = nCount; 7H|0.  
} 4l>U13~#  
} Z|fi$2k0!  
4TyzD%pOw  
{?q`9[Z  
/* ?]aVRmL  
**Utility.java s:cJF  
*/ #K*p1}rf  
package NetFox; pNZ3vTs6  
*
>HS>#S  
!E|R3eX_  
public class Utility { DliDBArxZ  
aHb&+/HZ  
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public Utility() (N/-blto  
{ x iz+R9p  
p&#ju*i6z  
&g>MZ"Z|  
} 4"\x#  
Udf\;G@  
//线程睡眠 9Zf  
public static void sleep(int nSecond) :hcOceNz  
{ .wUnN8crQ  
try{ K:% MhH-  
Thread.sleep(nSecond); auqN8_+=  
} 7HQL^Q  
catch(Exception e) 5!pNo*QK  
{ bSn={O"M  
e.printStackTrace (); rCsC}2O  
} }@/Ox  
} y
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Qmb+%z  
//日志 ;JgSA&'e  
public static void log(String sMsg) 1]Cbi7  
{ xFJT&=Af W  
System.err.println(sMsg); wWSw0 H/  
} a8v\H8@X  
>rSCf=  
C1(RgY|  
public static void log(int sMsg) bxO[y<|XL  
{ :'xZF2  
System.err.println(sMsg); {<a)+S.6U  
} sva-Sd8  
} [z"oi'"fQ  
)2q r^)  
4F6I7lu  
/* P: L6Zo-J  
**TestMethod.java ,7Ejb++/M,  
*/ U#- 5",X|  
package NetFox; S6\E  I5S  
$=#Lf[|f=  
m-a':  
public class TestMethod { '4D7:  
*3OlWnZ?  
|'uBkL0q  
public TestMethod() ueg%D+u  
{ ///xx/weblogic60b2_win.exe #T8jHnI  
try{ 7h2/8YUgQ  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); m:Rm(ga9  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); O_GHvLO=  
SiteFileFetch fileFetch = new SiteFileFetch(bean); >wL!`:c'"  
fileFetch.start(); "=KFag  
} 9YB?wh'S[  
catch(Exception e){e.printStackTrace ();} t-n'I/^5  
Nf2lw]-G4  
7xY&7 x(v  
} dd;rnev+  
t;0]d7ey'  
N})vrB;1  
public static void main(String[] args) I 9?X  
{ \zBZ$5 rE  
new TestMethod(); !KT.p2\  
} #;lEx'lKN  
} T+t7/PwC;  
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