http断点续传简单实现（java)

/* gT0yI;g]  
**SiteFileFetch.java |T$?vIG[  
*/ g(9*!g  
package NetFox; ux
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import java.io.*; ~abyjM  
import java.net.*; X!K>.r_Dg  
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public class SiteFileFetch extends Thread { Te L&6F$  
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SiteInfoBean siteInfoBean = null; //文件信息Bean #Zw:&' QB  
long[] nStartPos; //开始位置 Bh'fkW3  
long[] nEndPos; //结束位置 :MY=Q]l  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 :>JfBJ]|  
long nFileLength; //文件长度 P*BRebL:  
boolean bFirst = true; //是否第一次取文件 n)"JMzjQ<  
boolean bStop = false; //停止标志 -f&vH_eK  
File tmpFile; //文件下载的临时信息 `DF49YP"~  
DataOutputStream output; //输出到文件的输出流 e}1Q+h\  
\.}T_,I  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） G(.G>8pf  
public SiteFileFetch(SiteInfoBean bean) throws IOException Ba8=nGa4KY  
{  Q&xH  
siteInfoBean = bean; '"E!av>  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); I51]+gEN  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); I2WP/  
if(tmpFile.exists ()) ^J#*sn  
{ H" `'d  
bFirst = false; 'k[qx}  
read_nPos(); ,\iHgsZ  
} 0(wu  
else (Fon!_$:  
{ KCyV |,+n  
nStartPos = new long[bean.getNSplitter()]; sdZ$3oE.  
nEndPos = new long[bean.getNSplitter()]; BP@tI|  
} P?/JyiO}  
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} 6!"wiM"]  
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public void run() vvv'!\'#  
{ |Q
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//获得文件长度 &L$9Ii  
//分割文件 ZI!:  
//实例FileSplitterFetch }6%XiP|  
//启动FileSplitterFetch线程 r[i^tIv6As  
//等待子线程返回 qIQ=OY=6  
try{ B223W_0"o  
if(bFirst) (l^7EpNs  
{ MGm*({%  
nFileLength = getFileSize(); )1 T2u  
if(nFileLength == -1) ]}!@'+=  
{ iVn4eLK^v  
System.err.println("File Length is not known!"); JkJ @bh Eu  
} `^SRg_rH=`  
else if(nFileLength == -2) P-Y_$Nv0g  
{ yO1 7C  
System.err.println("File is not access!"); g,._3.D  
} YUEyGhkMV{  
else 6/S.sj~  
{ y|ZL<L  
for(int i=0;i<nStartPos.length;i++) #j
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{ }8x+F2i  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); "a)6g0gw  
} oL@-<;zKO  
for(int i=0;i<nEndPos.length-1;i++) T<pG$4_  
{ w-pgtO|Us  
nEndPos = nStartPos[i+1]; \t7yH]:>@  
} !6'N-b1  
nEndPos[nEndPos.length-1] = nFileLength; Dhn7N8(LF!  
} 4-.K<-T%D  
} b!@PS$BTxq  
^7spXfSAd  
HXa[0VOx  
//启动子线程 7x6M]1F  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; X>[i<ei  
for(int i=0;i<nStartPos.length;i++) (0NffM1  
{ mp
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fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), "5V;~}=S  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 60!%^O =  
nStartPos,nEndPos,i); _eiqs  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); i7.8H*z'  
fileSplitterFetch.start(); tRdf:F\X  
} T"z<D+pN  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Jr
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); tdH[e0x B  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", gPKf8{#%e  
nEndPos = " + nFileLength); r& a[
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// fileSplitterFetch[nPos.length-1].start(); Pz2 b  
wu.l-VmGp)  
[j0[c9.p[  
//等待子线程结束 +=8wZ]  
//int count = 0; mF;mJq<d  
//是否结束while循环 1 jidBzu<  
boolean breakWhile = false; BI`)P+K2  
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,~d0R4)  
while(!bStop) N@c GjpQ  
{ +-<G(^  
write_nPos(); <}RI<96  
Utility.sleep(500); e
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;&  
breakWhile = true; %v8&  
}#ZRi}f2VJ  
]#
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for(int i=0;i<nStartPos.length;i++) &|k=mxox\  
{ $os]$5(  
if(!fileSplitterFetch.bDownOver) ;Sivu-%  
{ %1Q:{m  
breakWhile = false; 0A)0Zw  
break; py'vD3Q  
} Gw<D'b)!  
} !l $d^y345  
if(breakWhile) =PRQ3/?5  
break; ,-AF8BP  
n?@
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s=n4'`y1  
//count++; ^w^e~0 S  
//if(count>4) #<*.{"T  
// siteStop(); s?EQ  
} -O *_+8f  
t<Acq07  
e3 v^j$  
System.err.println("文件下载结束！"); 1nAm\/&  
} rC-E+%y  
catch(Exception e){e.printStackTrace ();} oPmz$]_Z  
} u8zL[]>  
;l*%IMB  
+\T8`iCFB  
//获得文件长度 o`S``?`^)^  
public long getFileSize() PeIx41. +s  
{ r W`7<3  
int nFileLength = -1; 5b}w  
try{ "bhK%N;  
URL url = new URL(siteInfoBean.getSSiteURL()); .2E/(VM  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); NuQ!huh  
httpConnection.setRequestProperty("User-Agent","NetFox"); s>J5.Z7"'j  
-MTk9<qnT  
F$as#.7FF  
int responseCode=httpConnection.getResponseCode(); C.S BJ  
if(responseCode>=400) MI`qzC*%  
{ zIrOMh  
processErrorCode(responseCode); nc;eNB  
return -2; //-2 represent access is error C1D:Xi-  
} y47N(;vy  
rexf#W)  
_Xd"'cXw  
String sHeader; (.:*GUg  
A]|w1nq  
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for(int i=1;;i++) a}%f+`z  
{ sq2:yt  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); /2Wg=&H  
//Utility.log(in.readLine()); `7=$I~`  
sHeader=httpConnection.getHeaderFieldKey(i); AmF[#)90P  
if(sHeader!=null) vu+g65"  
{ Ah2 {kK  
if(sHeader.equals("Content-Length")) _2jL]mB  
{ PB@IPnB-  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); VgNB^w  
break; N\PdX$  
} Ur])*#  
} b{<?E };%  
else YCDH0M  
break; SI!A?34  
} |P>
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} #sw4)*v  
catch(IOException e){e.printStackTrace ();} o.ZR5`.  
catch(Exception e){e.printStackTrace ();} v#Rh:#7O%U  
qzZ/%{Ak  
t<UJR*R=L  
Utility.log(nFileLength); nFQuoU]ux  
JVIFpN"`  
vIRT$W' O}  
return nFileLength; Ey:68yU  
} '[WL8,.Q  
9f! M1  
~$u9  
//保存下载信息（文件指针位置） }:2##<"\t  
private void write_nPos() Og1-LP|X  
{ 2Xe1qzvo  
try{ v[Q)L!J1  
output = new DataOutputStream(new FileOutputStream(tmpFile)); i#la'ICwJ  
output.writeInt(nStartPos.length); QCb
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for(int i=0;i<nStartPos.length;i++) %R>n5m  
{ CGi;M=xr  
// output.writeLong(nPos); "Pwa}{  
output.writeLong(fileSplitterFetch.nStartPos); 5GM-*Ak@  
output.writeLong(fileSplitterFetch.nEndPos); wyy 1M+  
} K83'`W^  
output.close(); HV~Fe!J_  
} 9O 'j+?(`@  
catch(IOException e){e.printStackTrace ();} >:-e  
catch(Exception e){e.printStackTrace ();} uN)c!='I  
} {32m&a  
7+P;s,mi7  
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//读取保存的下载信息（文件指针位置） lEHx/#qt9  
private void read_nPos() *6?mZ*GYY  
{ fmixWL7.Zg  
try{ R,BJr y  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Z[nHo'  
int nCount = input.readInt(); p}QDX*/sSu  
nStartPos = new long[nCount]; #^L&H oo6  
nEndPos = new long[nCount]; ^s{Ff+]W  
for(int i=0;i<nStartPos.length;i++) 0#WN2f, <:  
{ ?b+Y])SJK  
nStartPos = input.readLong(); y^C5_w(^jZ  
nEndPos = input.readLong(); NF
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} U 3< 3T  
input.close(); RB %+|@c  
} t1w]L  
catch(IOException e){e.printStackTrace ();} WK6,K92  
catch(Exception e){e.printStackTrace ();} -zFJ)!/?  
} 6Hnez@d  
?z.?(xZ 6  
!`e`4y*N  
private void processErrorCode(int nErrorCode) 5!?5S$>  
{ e6taQz@}  
System.err.println("Error Code : " + nErrorCode); w x]?D%l  
} Onq^|r's&  
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//停止文件下载
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public void siteStop() oJ4HvrUO  
{ KM;H '~PZi  
bStop = true; A^,E~Z!x  
for(int i=0;i<nStartPos.length;i++) jc"sPrv5  
fileSplitterFetch.splitterStop(); ~LuGfPO^  
6=/sEzS'  
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} &<;T$Y  
} vqN/crJ@  
//负责部分文件的抓取 DP@1to@  
**FileSplitterFetch.java /Z6lnm7wJ  
*/ B/;>v  
package NetFox; *V kaFQZ$,  
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import java.io.*; q5_zsUR=  
import java.net.*; :XhF:c[.:  
I#2$CSJ  
qj;i03 +@  
public class FileSplitterFetch extends Thread { =_`q;Tu=  
X\m\yv}}  
/F;2wT;  
String sURL; //File URL &ww-t..  
long nStartPos; //File Snippet Start Position ,Wd=!if  
long nEndPos; //File Snippet End Position @
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int nThreadID; //Thread's ID *F1TZ_GS  
boolean bDownOver = false; //Downing is over U,WMP<5&  
boolean bStop = false; //Stop identical ^UKAD'_#%O  
FileAccessI fileAccessI = null; //File Access interface FygNWI'  
>pp/4Ia!  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException C>Hdp_Lm  
{ i6WPf:#wr  
this.sURL = sURL; *>a=ku:?  
this.nStartPos = nStart; R0qZxoo  
this.nEndPos = nEnd; C$[iduS  
nThreadID = id; \oWpyT _  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 `D(V_WZ  
} \ UrD%;sq  
08xo_Oysq  
X:UlL"G  
public void run() ]owgsR  
{ th73eC'  
while(nStartPos < nEndPos && !bStop) ^W$R{`  
{ Hl}lxK,]  
:f[ w  
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try{ LL e*|:  
URL url = new URL(sURL); 71@eJQ  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); .jD!+wv{9  
httpConnection.setRequestProperty("User-Agent","NetFox"); HX2u{
2$  
String sProperty = "bytes="+nStartPos+"-"; *F%1~  
httpConnection.setRequestProperty("RANGE",sProperty);  ?^Aj\z>  
Utility.log(sProperty); yzK<yvN  
%Lh%bqGz  
hZ1enej)  
InputStream input = httpConnection.getInputStream(); lNxP  
//logResponseHead(httpConnection); |p/*OFC6  
/p<9C?
 
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byte[] b = new byte[1024]; l+6c|([  
int nRead; 8e-nzc,]  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) A8.noV  
{ +UDt2  
nStartPos += fileAccessI.write(b,0,nRead); {`D]%e
RO  
//if(nThreadID == 1) ~Y`ys[Z m  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); D`@a*YIq  
} wKpBH}  
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O(I^:_eH  
Utility.log("Thread " + nThreadID + " is over!"); Xr K29a  
bDownOver = true; ^<!R%"o-  
//nPos = fileAccessI.write (b,0,nRead); A{s-
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} t[TM\j0jW  
catch(Exception e){e.printStackTrace ();} iQ" LIeD  
} 3g4=as4w  
} 4wSZ'RTSR  
B/l^=u+-  
n,FyK`x  
//打印回应的头信息 o:{Sws(=  
public void logResponseHead(HttpURLConnection con) 3*I\#Z4p1  
{ ?+EAp"{j  
for(int i=1;;i++) UWO3sZpU  
{ /V*SI!C<f  
String header=con.getHeaderFieldKey(i); F% n}vA`  
if(header!=null) {LjzkXs  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ^>E>\uz0v  
Utility.log(header+" : "+con.getHeaderField(header)); ~u$cX1M  
else !U% |pa  
break; 1\( N,'h  
} [TA.|7&  
} /!
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Xb:* KeZq  
 x(HHy,  
public void splitterStop() -ZE YzZqY  
{ qfXt%6L  
bStop = true; {{G3^ysa  
} l1T`[2  
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oIO@#   
} b\JU%89  
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[lML^CYQ  
/* ZY,$oFdsi  
**FileAccess.java 'l(s)Oa{M:  
*//文件访问(定位，写) zI[<uvxzW`  
package NetFox; /lR*ab  
import java.io.*; 8a*&,W  
P@@MQ[u?!.  
C:No ^nH>  
public class FileAccessI implements Serializable{ Evj%$7H1L1  
SAq.W"ri  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 8TpYt)]S  
RandomAccessFile oSavedFile; ((`\i=-o5  
long nPos; Z&>Cdgt*  
?u#s?$Y?  
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public FileAccessI() throws IOException m Z +dr[  
{ EHq;eF  
this("",0); HXT"&c|  
} )w4U]inJ$"  
HlX~a:.7  
3:xx:Jt  
public FileAccessI(String sName,long nPos) throws IOException <O=0^V  
{ l| uiC%T  
oSavedFile = new RandomAccessFile(sName,"rw"); Rw `ezC#  
this.nPos = nPos;  [{2v}  
oSavedFile.seek(nPos); ;-"!
p  
} k~AtnI  
i ZPNss  
F_0D)H)N@  
public synchronized int write(byte[] b,int nStart,int nLen) 564L.^$@|  
{ IT:WiMD
Q}  
int n = -1; CN(-Jd.b  
try{ _w\i~To!  
oSavedFile.write(b,nStart,nLen); *Zg=cI@)(  
n = nLen; m19\H  
} c/88|k  
catch(IOException e) JYj*.Q0  
{ e1XKlgl  
e.printStackTrace (); tXA?[ S  
} 6IRRRtO(  
p#qla'  
MS#"TG/)  
return n; A-1KTD  
} z&0[F`U  
&Ih}"  
<_8bAO8\  
} w tGS"L  
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fsPsP`|  
/* Q\s+w){f%  
**SiteInfoBean.java @_"cMU!  
*/ nGWy4rY2S  
package NetFox; F(.`@OO  
oUsfO-dET^  
7:F0?l*  
public class SiteInfoBean { 43h06X`  
HqsqUS3[  
[2xu`HT02  
private String sSiteURL; //Site's URL Y[)mHs2  
private String sFilePath; //Saved File's Path nHeJ20  
private String sFileName; //Saved File's Name xO:h[  
private int nSplitter; //Count of Splited Downloading File ?8kFAf~  
4u*n7di$9d  
!pU^?Hy=  
public SiteInfoBean() l[_antokn  
{//nSplitter的缺省值为5 G~C-tAB  
//default value of nSplitter is 5 U}:+Hz9
  
this("","","",5); [Y!HQ9^LEp  
} *=B<S/0  
9c4p9b!  
7L/LlO/  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 6X9$T11Vc  
{ m$W2E.-$'#  
sSiteURL= sURL; clyp0`,7  
sFilePath = sPath; _;^x^  
sFileName = sName; jFg19C{=X  
this.nSplitter = nSpiltter; ^!exH(g  
du}HTrsC  
~M* UMF^  
} ~]no7O4  
y`$qcEw  
7;@YR
 
public String getSSiteURL() PW%ith1)<  
{ bA0H  
return sSiteURL; %"c;kvw  
} yqK_|7I+  
jtfC3E,U  
B>'J5bZsw  
public void setSSiteURL(String value) %!-t7K^mFq  
{ gktlwiCZ  
sSiteURL = value; H@zZ[  
} ?>ZrdfTwz,  
Fv,
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XFs7kTY  
public String getSFilePath() fA?Wf[`x  
{ Y ?~n6<  
return sFilePath; D`Vb3aNB=L  
} 'bZw-t!M@  
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JcP<@bb>B  
public void setSFilePath(String value) o6 NmDv5  
{ ,1|=_M31  
sFilePath = value; tjV63`LD  
} M7Z&t'=  
$B>L_~cS  
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public String getSFileName() S+6YD0  
{ ~ cu+QR)  
return sFileName; d_:tiHw$  
} .'+JA:3R  
+NB5Fd4  
;
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public void setSFileName(String value) lr)MySsu#H  
{ s#0m  
sFileName = value; N/0Q`cQ-  
} ?OO
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M>RLS/r>d  
|M<R{Tt}nf  
public int getNSplitter()  wN0?~  
{ YE"MtL {  
return nSplitter; $1Z3yb^  
} k ;vOPcw  
S=w~bz,/  
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public void setNSplitter(int nCount) |SJ%Myy  
{ iu+H+_  
nSplitter = nCount; hoPh#? G  
} n n8N 9w  
} ZZ0b!{qj3  
W89J]#v)k  
ac4dIW{$3  
/* X~; *zYd5  
**Utility.java +(q r{G?  
*/ 2)^T[zHe  
package NetFox; eLN(NSPoS  
E&W4`{6K4  
P/9|mYmsq  
public class Utility { 7,9zj1<  
!Nhq)i  
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public Utility() }<P%W~  
{ zgpvI~Ck  
H&ZsMML/%  
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} oP<E)  
1\,wV,  
//线程睡眠 l>>,~  
public static void sleep(int nSecond) lFM'F[-?-  
{ 5th\_n}N2/  
try{ BtWm ZaKi  
Thread.sleep(nSecond); xF9PjnWF=  
} 0.t1p(x;  
catch(Exception e) iuq%Q\0@w  
{ N(&/ Ud  
e.printStackTrace (); !}uev  
} F a'2i<  
} &4l>_  
9_S>G$
9D  
//日志 Ed~2Qr\65  
public static void log(String sMsg) lhV'Q]s@6  
{ }NJ? .Y  
System.err.println(sMsg); d5B96;3  
} F_Mi/pB^`9  

v:] AS:  
VlFDMw.4.+  
public static void log(int sMsg) S)\%.~ n  
{ u>-!5=D8  
System.err.println(sMsg); ?l<u%o  
} ddD $
4+  
} s8N\cOd#i  
7[ra#>e8'  
!23#Bz7  
/* mM7S9^<UH  
**TestMethod.java $.@)4Nu!_  
*/ MoP0qNk  
package NetFox; A5ps|zidI  
~FV Z0%+,  
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public class TestMethod { >m{)shBX  
9m fYB  
cy6P=k*  
public TestMethod() pJ#R :#P  
{ ///xx/weblogic60b2_win.exe 6!n%SUt  
try{ S|%f<zAtJ  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); @kLpK  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); A%s"WSx,  
SiteFileFetch fileFetch = new SiteFileFetch(bean); |3MqAvPJ  
fileFetch.start(); Ot]P
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} G =+sW  
catch(Exception e){e.printStackTrace ();} ~WJEH#  
U>^-Db
]  
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l&1  
} h^5'i}@u  
of^N4  
d\V\,%&.  
public static void main(String[] args) k]"Rg2
>%  
{ T%xB|^lf  
new TestMethod(); &k?Mt#J  
} 4PEJ}BW  
} @&]j[if(s  
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