http断点续传简单实现（java)

/* 1^$ vmULj  
**SiteFileFetch.java Q/L:0ovR  
*/ :IvKxOv  
package NetFox; ?bW|~<X~  
import java.io.*; u6;SgPw  
import java.net.*; 3l
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public class SiteFileFetch extends Thread { fn]f$n*`  
``DS?pUY  
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SiteInfoBean siteInfoBean = null; //文件信息Bean HvLvSy1U  
long[] nStartPos; //开始位置 Xb.WI\Eh  
long[] nEndPos; //结束位置 w7s+6,  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 xmsw'\  
long nFileLength; //文件长度 hv2@}<r?  
boolean bFirst = true; //是否第一次取文件 [ lW~v:W  
boolean bStop = false; //停止标志 $QN}2lJ>  
File tmpFile; //文件下载的临时信息 #[ipJ %  
DataOutputStream output; //输出到文件的输出流 oYI7 .w  
)w=ehjV^m  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） *\L\Bzm  
public SiteFileFetch(SiteInfoBean bean) throws IOException ncjtv"2R  
{ z^'3f!:3   
siteInfoBean = bean; :*k  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); V]&0"HX2r!  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); <XDYnWz  
if(tmpFile.exists ()) &3#19v7/  
{ ===M/}r  
bFirst = false; \c(R#*0,  
read_nPos(); rI23e[  
} {d|e@`"T  
else 2guWWFS  
{ 2M1}`H\  
nStartPos = new long[bean.getNSplitter()]; ;Hk{bz
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nEndPos = new long[bean.getNSplitter()]; &>,c..Ke  
} Ahv%Q%m%2  
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} INt]OPD  
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public void run() bVO{,P2o  
{ qp;eBa  
//获得文件长度 G 
|033(j  
//分割文件 Y)lYEhF  
//实例FileSplitterFetch l3[2b Qx  
//启动FileSplitterFetch线程 U|ZYoc+](  
//等待子线程返回 2SVBuV/R  
try{ }M*yE]LL;Z  
if(bFirst) ZgarxV*  
{ 3V2dN)\  
nFileLength = getFileSize(); D;
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if(nFileLength == -1) Okxuhzn>"  
{ F5s Pd  
System.err.println("File Length is not known!"); X2\1OWR0  
} j%%& G$Tfu  
else if(nFileLength == -2) 9 M>.9~  
{ dPvRbwH<  
System.err.println("File is not access!"); /z
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} ;=r_R!
d@  
else {^(h*zxn  
{ t`%Xxxu  
for(int i=0;i<nStartPos.length;i++) 3}hJ`xQ  
{ oA+/F]XJ  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); GP<PU  
} 
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for(int i=0;i<nEndPos.length-1;i++) 
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{ 0KT^V R  
nEndPos = nStartPos[i+1]; (t[sSl  
} -,YoVB!T  
nEndPos[nEndPos.length-1] = nFileLength; |YEq<wbQ  
} {/ef`MxV }  
} [P_@-:(O  
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oyC5M+shP9  
//启动子线程 VkW N1A  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; |tn.ZEgw3~  
for(int i=0;i<nStartPos.length;i++) WtS5i7:<Y  
{ w{+G/Ea  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Q7#Yw"#G!  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),
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nStartPos,nEndPos,i); 6 rp(<D/_  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); F .hA.E  
fileSplitterFetch.start(); v=8sj{g3,3  
} HAKB@h)  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), [[FDt[
l4  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); r&rip^40  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", {f1iys'Om  
nEndPos = " + nFileLength); L*(Sh2=_  
// fileSplitterFetch[nPos.length-1].start(); H;w8[ImK  
FHOF6}if  
 4>R)2g  
//等待子线程结束 Gv\39+9=  
//int count = 0; VPi*9(LS  
//是否结束while循环 &dsXK~9M>  
boolean breakWhile = false; xw
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while(!bStop) )JA9bR <  
{ y?Cq{(  
write_nPos(); z ?L]5m`H  
Utility.sleep(500); }e
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breakWhile = true; "rVf{
  
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for(int i=0;i<nStartPos.length;i++) !FA[ ]d4  
{ -4Hf5!  
if(!fileSplitterFetch.bDownOver) ZVIlVuZ}  
{ y?P4EVknM3  
breakWhile = false; >S}^0vNZX  
break; +d!"Zy2|B  
} `=%mU/v  
} i K,^|Q8  
if(breakWhile) ]iezwz`'  
break; \p.eY)>  
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//count++; %LjhK,'h  
//if(count>4) \%/Y(YVm  
// siteStop(); &"6%D|Z0  
} +bdjZD3  
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System.err.println("文件下载结束！"); 1
|XC$0  
} |SX31T9rG  
catch(Exception e){e.printStackTrace ();} RLNto5?  
} Vw";< <0HZ  
p>h&SD?b  
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//获得文件长度 Jp 7m$D%  
public long getFileSize() $+WMKv@<  
{ l1UN.l'p  
int nFileLength = -1; ~O8Xj6  
try{ b wqd`C  
URL url = new URL(siteInfoBean.getSSiteURL()); kO}QOL4  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); |%$mN{  
httpConnection.setRequestProperty("User-Agent","NetFox"); {Rtl<W0  
Y^2]*e%  
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int responseCode=httpConnection.getResponseCode(); `xsU'Wd^<  
if(responseCode>=400) *pSD[E>SU  
{ AQgagE^  
processErrorCode(responseCode); z8JdA%YBM  
return -2; //-2 represent access is error hZtJ
LY  
}
>
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? t_$C,A+  
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String sHeader; w,VUWja  
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for(int i=1;;i++) oi\e[qE  
{ QHPC?a6CD  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); wS;hC&~2  
//Utility.log(in.readLine()); Bhf4 /$  
sHeader=httpConnection.getHeaderFieldKey(i); ^GC 8^f  
if(sHeader!=null) s)5W:`MH?  
{ uePa4e!  
if(sHeader.equals("Content-Length")) + 0 |d2_]E  
{ ay>u``$R  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ,}23  
break; XK,l9 {*  
} ;@s'JSPt  
} nO;t5d  
else $E6bu4I  
break; ?bw1zYP  
} J_N`D+m  
} `3'4_@7s9  
catch(IOException e){e.printStackTrace ();} E-i<^&E  
catch(Exception e){e.printStackTrace ();} LWIPq"  
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Utility.log(nFileLength); 4n}^1eQ9  
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return nFileLength; =*=qleC3  
} Zd<8c^@  
IgNL1KRD  
dFzlcKFFD  
//保存下载信息（文件指针位置） M&ec%<lM  
private void write_nPos()
]#P>wW  
{ Q|Go7MQZ@k  
try{ <~iA{sY)O  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 'w`3( ':=  
output.writeInt(nStartPos.length); &k@r23V7r  
for(int i=0;i<nStartPos.length;i++) pa2cM%48  
{ *,#T&M7D  
// output.writeLong(nPos); [*z`p;n2D  
output.writeLong(fileSplitterFetch.nStartPos); o}6d[G>  
output.writeLong(fileSplitterFetch.nEndPos); VhX~sJ1%Gp  
} ,#hx%$f}d  
output.close(); :FWo,fq?:{  
} Kn4x_9  
catch(IOException e){e.printStackTrace ();} c~v(bK  
catch(Exception e){e.printStackTrace ();} F8OE  
} 1zWEK]2.R  
:GN7JxD#  
+?y9EZB%  
//读取保存的下载信息（文件指针位置） yGX"1Fb?;x  
private void read_nPos() X.FFBKjf[e  
{ Y4,LXuQ
 
try{ 1%k$9[!l%  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); kdp- 
|9  
int nCount = input.readInt(); +kZW:t!-  
nStartPos = new long[nCount]; xAJuIR1Hi  
nEndPos = new long[nCount]; E;Q ,{{#  
for(int i=0;i<nStartPos.length;i++) b&xlT+GN  
{ D>m!R[!o  
nStartPos = input.readLong(); qcR"i+b  
nEndPos = input.readLong(); m6YDyQC  
} obtXtqew  
input.close(); `uLH3sr  
} WN9K*Tt~o&  
catch(IOException e){e.printStackTrace ();} C ]
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catch(Exception e){e.printStackTrace ();} | x/Z qY  
} ?nV& :~eY  
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|  
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private void processErrorCode(int nErrorCode) 6rg?0\A<  
{ KQ2jeJ/pj  
System.err.println("Error Code : " + nErrorCode); +"F9yb  
} JVt(!%K}&  
vY'E+M"+@  
qgk6 \&K[  
//停止文件下载 %eQw\o,a  
public void siteStop() `AcT}.u  
{ W=ar&O~}n  
bStop = true; ;=F]{w]$+  
for(int i=0;i<nStartPos.length;i++) AD4Ot5  
fileSplitterFetch.splitterStop(); 4pC.mRu 0  
>Z&Y!w'A|u  
<
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} =6^phZ(  
} \&.]!!Q  
//负责部分文件的抓取 1k?k{Ri  
**FileSplitterFetch.java iES?}K/q  
*/ a@}A;y'd  
package NetFox; %VmHw~xyF:  
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<P#]U"?A  
import java.io.*; 8}<4f|?  
import java.net.*; {v~.zRW%]r  
5&N55?G6  
a^QyYX}\qR  
public class FileSplitterFetch extends Thread { lCC(N?%Q  
|}KNtIX\G  
Jrm 9,7/  
String sURL; //File URL TaTs-]4  
long nStartPos; //File Snippet Start Position kZJ.G  
long nEndPos; //File Snippet End Position )ND%MYJSq  
int nThreadID; //Thread's ID D0H
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boolean bDownOver = false; //Downing is over P8=!/L2?  
boolean bStop = false; //Stop identical l4smAT  
FileAccessI fileAccessI = null; //File Access interface M73d^
z  
x9s1AzM{  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException SxWK@)tP  
{ [(PD2GO+  
this.sURL = sURL; )MlT=k6S  
this.nStartPos = nStart; 
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this.nEndPos = nEnd; E[E7GsmqV  
nThreadID = id; `/\Z{j0_  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 DU=rsePWE  
} <Zn-P  
YH^h?s  
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public void run() "JJEF2e@Z  
{ eV)'@8p
 
while(nStartPos < nEndPos && !bStop) QM'Db`B  
{ 2!E@Gbhm5  
JOvRUDZ  
yo@S.7[/  
try{ rj> _L  
URL url = new URL(sURL); 8O_0x)X  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 5y%-K=d  
httpConnection.setRequestProperty("User-Agent","NetFox"); Hd9vS"TN]  
String sProperty = "bytes="+nStartPos+"-"; [9>h! khs  
httpConnection.setRequestProperty("RANGE",sProperty); Od5I:p]N  
Utility.log(sProperty); /n&Y6@W  
kjVJ!R\  
=%+O.  
InputStream input = httpConnection.getInputStream(); ()+PP}:$A  
//logResponseHead(httpConnection); 'g7eN@Wh.z  
b w2KD7  
bJ#]Xm(]D  
byte[] b = new byte[1024]; X cDu&6Dy  
int nRead; <JNiW8 PG  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) jt?.g'  
{ kvo V?<!  
nStartPos += fileAccessI.write(b,0,nRead); W`2Xn?g  
//if(nThreadID == 1)
MzudCMF  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); V.U9Q{y
"  
} rjLPX  
;%_s4  
F:B8J4/  
Utility.log("Thread " + nThreadID + " is over!"); P/
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bDownOver = true; -=)Al^V4T  
//nPos = fileAccessI.write (b,0,nRead); qPI1\!z6  
} h.ln%6:d  
catch(Exception e){e.printStackTrace ();} U81--'@y  
} 4Cn% h)w  
} MR{JMo=r  
O<EFm}Ae  
$VRVMY [q  
//打印回应的头信息 WXzSf.8p|  
public void logResponseHead(HttpURLConnection con) dW`!/OaQD  
{ GL<u#[  
for(int i=1;;i++) -fILXu  
{ iF#|Z$g-(  
String header=con.getHeaderFieldKey(i); 2V6kCy@V  
if(header!=null) eK)R=M@i  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); mIy|]e`SJ  
Utility.log(header+" : "+con.getHeaderField(header)); 8\H*Z2yF+  
else 9KgGK cy%  
break; Gi=s|vt  
} t6JM%  
} $/p/9 -  
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public void splitterStop() N">4I)  
{ eGF+@)K1"  
bStop = true; P56B~M_  
}
6 J B"qd  
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#FNSE*Y  
} o,D7$WzL  
6";ew:Ih^  
!Yi2g-(  
/* ?Xq"Q^o4#e  
**FileAccess.java |DBj<|SX  
*//文件访问(定位，写) 9N@m><N84  
package NetFox; <Mq vGXI  
import java.io.*; Vhi4_~W3j]  
><Awk~KR  
3<%ci&B  
public class FileAccessI implements Serializable{ ^_rBEyz@  
Nm.G,6<J  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 j'QPJ(`~1l  
RandomAccessFile oSavedFile; K}j["p<!  
long nPos; K275{ydN  
%p t^
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public FileAccessI() throws IOException +$;*"o  
{ 2.>aL  
this("",0); M8{J  
} `:>N.9'o  
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public FileAccessI(String sName,long nPos) throws IOException 9(AY7]6  
{ `$oy4lDKQ  
oSavedFile = new RandomAccessFile(sName,"rw"); p`I[3/$3  
this.nPos = nPos; ^1mnw@04  
oSavedFile.seek(nPos); N}\%r&KR=  
} o0}kRL  
6a!b20IZh  
@yj$  
public synchronized int write(byte[] b,int nStart,int nLen) 
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{ LuE0Hb"S8  
int n = -1; 9 7Ua,  
try{ ][TA7pDPV  
oSavedFile.write(b,nStart,nLen); iz-B)^8.  
n = nLen; \'9(zbvz9  
} uy'qIq  
catch(IOException e) Q*54!^l+_r  
{ ^(+@uuBx  
e.printStackTrace (); ]*]#I?&'Hx  
} =!N,{V_  
"969F(S$  
Z(Z$>P&4  
return n; bHK[Z5  
} f>zd,|)At  
P
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} nIEIb.-  
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/* ym;I(TC+  
**SiteInfoBean.java l0K_29^  
*/ 9'Cu9nR  
package NetFox; 
*ORa@x  
C1w6[f1+  
,~G:>q$ad  
public class SiteInfoBean { K +l-A>Ic  
U9Gg#M4tY  
vtw97G  
private String sSiteURL; //Site's URL ecMpU8}rR  
private String sFilePath; //Saved File's Path Ie7S'.Lmq  
private String sFileName; //Saved File's Name q${+I(b,  
private int nSplitter; //Count of Splited Downloading File n3_|#1Qu  
%{B4M#~  
>uP1k.z
'I  
public SiteInfoBean() ufB9\yl{~  
{//nSplitter的缺省值为5 cMoBYk  
//default value of nSplitter is 5 W_bA.zT{  
this("","","",5); XES$V15  
} qNX+!Y}y  
qoAJcr2uN  
U]PsL3:  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) kIJ=]wU|v  
{ _T(77KLn;  
sSiteURL= sURL; -?L3"rxAP  
sFilePath = sPath; #:E^($v  
sFileName = sName; =6d'/D#J  
this.nSplitter = nSpiltter; PnJA'@x  
@g]>D  
S76xEL  
} $VJE&b  
'NN3XyD
 
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public String getSSiteURL() T!1Np'12zF  
{ W2]%QN=m$  
return sSiteURL; ZK`x(h{p)  
} L.x`Jpq(3  
+%H2;8{F  
:v%iF!+.P  
public void setSSiteURL(String value) Q94p*]W"  
{ )(h<vo)-zX  
sSiteURL = value; H)pB{W/  
} V>"NVRY  
p]Q(Z  
g+QNIM>  
public String getSFilePath() 3A'9=h,lVK  
{ fiQ/ &]|5  
return sFilePath; F-<c.0;6  
} vpP8'f.  
:auq#$B  
X<uH [  
public void setSFilePath(String value) @#::C@V]  
{ @5\/L6SRfL  
sFilePath = value; fl71{jJ_  
} rW[7 _4  
)AXa.y  
{W%/?d9m  
public String getSFileName() BFPy~5W  
{ Wl{wY,u  
return sFileName; kj@m5`G  
} 66'AaA;0^i  
7,ffY/  
TL@{yJ;s  
public void setSFileName(String value) $*;ke5Dm4  
{ kjRL|qx`a;  
sFileName = value; *W<|5<<u@  
} #IxCI)!I{[  
$`txU5#vs  
#4{9l SbU  
public int getNSplitter() +.|8W!h`1  
{ lt|UehJF  
return nSplitter; rlSflcK\\(  
} |c:xK{Ik  
~c|{PZ9U  
AUwIF/>F(]  
public void setNSplitter(int nCount) fHacVjJ  
{ 4Dv42fO  
nSplitter = nCount; ILT.yxV  
} 5u
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} ^:]~6p#  
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/* bEl)/z*gy/  
**Utility.java q6zKyO
E  
*/ h9j/mUwV  
package NetFox; oT[8Iu  
d1/uI^8>  
k1_3\JO"6  
public class Utility { #3((f[  
YojYb]y+j  
S@vLh=65  
public Utility() BCw0kq@  
{ 5#$5ct  
av}pT)]\  
]y<<zQ_fhY  
} zP#%ya:I  
^ ,yh38
4  
//线程睡眠 \bumB<w(]  
public static void sleep(int nSecond) y%xn(Bn  
{ @(s"5
i.`)  
try{ P[a\Q`}L  
Thread.sleep(nSecond); {9YNv<3  
} }~$96|J  
catch(Exception e) NTL`9b  
{ (ZHEPN  
e.printStackTrace (); ?o.Q  
} .RxAYf|  
} Zn"1qLPF  
\!,qXfTMB  
//日志 |k=L&vs  
public static void log(String sMsg)  B!+`km5  
{ |\S p IFH1  
System.err.println(sMsg); 9|RR;k[  
} kc-v(WIC  
"+:~#&r  
aC=D_JJ
\  
public static void log(int sMsg) Jp]eFaqp  
{ 7cMSJM(]G  
System.err.println(sMsg); PK|"+I0  
} RE}$(T=  
} ({#M*=&"  
H}B%OFI\+  
[_?dpaTt  
/* -% Z?rn2  
**TestMethod.java 8m;tgMFO  
*/ l:H}Y3_I  
package NetFox; Ff@Cs0R  
uGMmS9v$ J  
BV01&.<|  
public class TestMethod { QL_9a,R'r  
',P E25Z  
&?gvW//L2  
public TestMethod() 7;;HP`vY  
{ ///xx/weblogic60b2_win.exe {@w!kl~8  
try{ G@Y!*ZH*f  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); O5eTkKUc  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); aZ{]t:]  
SiteFileFetch fileFetch = new SiteFileFetch(bean); #0;ULZ99aH  
fileFetch.start(); yxz"9PE/P  
} jjrhl  
catch(Exception e){e.printStackTrace ();} amH..D7_>  
q:/<^|  
`c~J&@|  
} w `0m[*  
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oWo/QNw9  
public static void main(String[] args) &KS*rHgt?  
{ !+# pGSk  
new TestMethod(); J"Z=`I)KON  
} 4]18=?r>  
} Dw6mSsC/  
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