http断点续传简单实现（java)

/* ij),DbWd  
**SiteFileFetch.java Tk:y>P!%a  
*/ lb('r"*.  
package NetFox; "
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import java.io.*; M@3H]t?  
import java.net.*; :U>
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public class SiteFileFetch extends Thread { VQ;=-95P  
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( FRf.mv{  
SiteInfoBean siteInfoBean = null; //文件信息Bean l]Sui_+ZU  
long[] nStartPos; //开始位置 8K/lpqw  
long[] nEndPos; //结束位置 D.e*IP1R  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ZjK~s)RC  
long nFileLength; //文件长度 90!Ib~7zH  
boolean bFirst = true; //是否第一次取文件 +A3H#'  
boolean bStop = false; //停止标志 a*8}~p,  
File tmpFile; //文件下载的临时信息 ;FBc^*q  
DataOutputStream output; //输出到文件的输出流 |"< I\Vs:  
!|/fVWH  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） N@$%0!  
public SiteFileFetch(SiteInfoBean bean) throws IOException )em.KbsPPF  
{ Z0=OR^HjA  
siteInfoBean = bean; uwka 2aSS  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); |<0@RCgM  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); #rwR)9iC0  
if(tmpFile.exists ()) *GhRU5  
{ BTyVfq sx  
bFirst = false; >R<fm  
read_nPos(); [C6?:'}FA  
} \zUsHK?L"t  
else NC}#P<U  
{ ){:aGGtko  
nStartPos = new long[bean.getNSplitter()]; v
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nEndPos = new long[bean.getNSplitter()]; O#\>j  
} =.c"&,c?L  
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} K;PpS*!  
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public void run() O~el2  
{ I1~g?jpH  
//获得文件长度 bRK9Qt#3  
//分割文件 Tjqn::~D  
//实例FileSplitterFetch B .mV\W  
//启动FileSplitterFetch线程 M}Mzm2d#`  
//等待子线程返回 *@nUas2"  
try{ ?s]`G'=>V`  
if(bFirst) JPG!c
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{ [ UJj*n  
nFileLength = getFileSize(); )QD}R36Ic  
if(nFileLength == -1) C.-a:oQ[  
{ o{p_s0IX;S  
System.err.println("File Length is not known!"); 3XtGi<u  
} 9_3M}|V$^e  
else if(nFileLength == -2) &?6w2[}  
{ \tx/!tA  
System.err.println("File is not access!"); Cj+=9Dc  
} v_0!uT5~NE  
else #8jd,I%L  
{ k Dt)S$N4n  
for(int i=0;i<nStartPos.length;i++) MavO`m&Cg  
{ (SK5pU  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ]w>fnew  
} N sL"p2w~  
for(int i=0;i<nEndPos.length-1;i++) uw!|G>  
{ "S:N-Tf%U  
nEndPos = nStartPos[i+1]; 8A.7=C' z  
} 'wrpW#  
nEndPos[nEndPos.length-1] = nFileLength; tqCg<NH.!m  
} [@Y q^.6t  
} C6~dN&q  
/p0LtUMu  
us%RQ8=k  
//启动子线程 zQ}N mlk  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; CaBS0' n  
for(int i=0;i<nStartPos.length;i++) %LHV0u  
{ rbbu
SI  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), [i7)E]*oTA  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ^;Q pE  
nStartPos,nEndPos,i); H~]o]uAi"  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); qhtAtP>i"  
fileSplitterFetch.start(); {W<-f?  
} jqWvLBU!  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ^6>|!  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); =osw3"ng  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", :j<JZs>`R  
nEndPos = " + nFileLength); ZiYzsn  
// fileSplitterFetch[nPos.length-1].start(); 0\@|M@X=  
C/Bx_j((  
? M_SNv  
//等待子线程结束 ZS]f+}0/}  
//int count = 0; `r(J6,O  
//是否结束while循环 /ASI0h  
boolean breakWhile = false; P'9io!
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while(!bStop) `0|&T;7  
{ L$Ar]O)  
write_nPos(); J6D$ i+  
Utility.sleep(500); Ilb |:x"L  
breakWhile = true; N06O.bji  
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for(int i=0;i<nStartPos.length;i++) }yDq\5s Q[  
{ v:1Vli.  
if(!fileSplitterFetch.bDownOver) 9mphj)`d;#  
{ _C=[bI@  
breakWhile = false; >0#q!H,X  
break; arVf"3a  
} JBAK*g  
} XYF~Q9~  
if(breakWhile) VQMd[/  
break; |o=ST  
t`t:qko  
5XO'OSdYq  
//count++; yc=#Jn?S  
//if(count>4) q<[ke   
// siteStop(); }IkEyJsk  
} h_
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W;]UP$5l  
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System.err.println("文件下载结束！"); ]V^.!=gh$  
} 6v O)s!b  
catch(Exception e){e.printStackTrace ();} 6-14Htsk6  
} 4Olv8nOe<  
aw%v
u  
)"jn{%/t  
//获得文件长度 ]{+M>i[  
public long getFileSize() [k7N+W8  
{ fUKdC\WL  
int nFileLength = -1; LY:?OGh  
try{ ?mfWm{QTt  
URL url = new URL(siteInfoBean.getSSiteURL()); 8!Mzr1:  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ,xe@G)a  
httpConnection.setRequestProperty("User-Agent","NetFox"); %aE7id>v6  
(`.qG &6p  
G:C6`uiy`  
int responseCode=httpConnection.getResponseCode(); <&EO=A  
if(responseCode>=400) "|r^l  
{ s1 ^mk]  
processErrorCode(responseCode); !vVjZ  
return -2; //-2 represent access is error p2DNbY\]  
} as|c`4r\O  
;6 6_G Sjz  
}rA+W-7  
String sHeader; m
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)LrCoI =|  
( WtE`f;Q  
for(int i=1;;i++) .P:f  
{ EJ;0ypbG  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); n.6 0$kR`  
//Utility.log(in.readLine()); U2>dwn  
sHeader=httpConnection.getHeaderFieldKey(i); Fif^V  
if(sHeader!=null) h)l&K%4;  
{ qb&NS4#  
if(sHeader.equals("Content-Length")) eTRx6Fri(  
{ <Bb<?7q$ld  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); n5*{hi  
break; Fp6[W5>(-  
} +'Y(V&  
} +;wqX]SD&  
else = EChH@3  
break; %OTA5  
} 'Kzr-)JS  
} SAE'?_  
catch(IOException e){e.printStackTrace ();} cvXI]+`<3\  
catch(Exception e){e.printStackTrace ();} +s(IQt  
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Utility.log(nFileLength); 6|>\&Y!Q  
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return nFileLength; KgTGxCH  
} G<^]0`"+)t  
:UDn^(#  
0B$7S,2  
//保存下载信息（文件指针位置） ~UJu @M  
private void write_nPos() <,4R2'  
{ vXM/nw|5  
try{ fov=Yd!  
output = new DataOutputStream(new FileOutputStream(tmpFile)); +x9"#0|k;  
output.writeInt(nStartPos.length); Q#ZD&RZ9.  
for(int i=0;i<nStartPos.length;i++) yK%GsCJd:  
{ <X I35\^  
// output.writeLong(nPos); 4>"cc@8&~  
output.writeLong(fileSplitterFetch.nStartPos); 4lh   
output.writeLong(fileSplitterFetch.nEndPos); p-'6_\F.Ke  
} q4
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output.close(); 'f?&EsIV?  
} eFj6p
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catch(IOException e){e.printStackTrace ();} _z(5e  
catch(Exception e){e.printStackTrace ();} Ad`[Rt']kI  
} B`?N0t%X  
.xLF}{u  
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//读取保存的下载信息（文件指针位置） *n*N|6+  
private void read_nPos() PZ!dn%4jy  
{ yhtvr5z1  
try{ <`p75B  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); u_6B
HsU  
int nCount = input.readInt(); ueE?"Hk  
nStartPos = new long[nCount]; 4/`h@]8P  
nEndPos = new long[nCount]; A M1C $  
for(int i=0;i<nStartPos.length;i++) 4I#eC#"  
{ mj(&`HRs4  
nStartPos = input.readLong(); Mi/ &$"=  
nEndPos = input.readLong(); ]Ic?:lKN  
} V^`?8P8d  
input.close(); 4$?wD <  
} |:(23O  
catch(IOException e){e.printStackTrace ();} :B*vkwT  
catch(Exception e){e.printStackTrace ();} =(|xU?OL  
} C7jc6(>m  
JwI`"$>w  
;la#Vf:]  
private void processErrorCode(int nErrorCode) s7.p$r  
{ FfYd+]+?  
System.err.println("Error Code : " + nErrorCode); E&];>3C  
} s=nVoc{Yt  
,h@R' f!  
0Y6q$h>4  
//停止文件下载 gP%|:"  
public void siteStop() znQ'm^h  
{ `j}_BW_  
bStop = true; _Vo)<--+I  
for(int i=0;i<nStartPos.length;i++) 'Wf?elB+  
fileSplitterFetch.splitterStop(); 1A?\BJ"  
5U)ab3:  
}#ep}h  
} PHRGhKJW})  
} 9b"9m*gC  
//负责部分文件的抓取 `s>UU- 9  
**FileSplitterFetch.java 4{*tn"y  
*/ |ilv|UV  
package NetFox; XJ:>UNf5;  
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0~Iu7mPY  
import java.io.*; P>{US1t  
import java.net.*; J+}+"h~.  
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public class FileSplitterFetch extends Thread { |%'6f}fnE  
"+n4c'  
_}I(U?Q-C  
String sURL; //File URL H:q)^$s  
long nStartPos; //File Snippet Start Position a@fE46o6<  
long nEndPos; //File Snippet End Position z29qARiX  
int nThreadID; //Thread's ID pK6e/eC  
boolean bDownOver = false; //Downing is over mfeMmKFu\  
boolean bStop = false; //Stop identical HBh` 2Q  
FileAccessI fileAccessI = null; //File Access interface ggm2%|?X  
" K 8&{=  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ^])e[RN7?n  
{ zd*3R+>U'>  
this.sURL = sURL; $N}/1R^?r  
this.nStartPos = nStart; tjZ\h=  
this.nEndPos = nEnd; i<4>\nc  
nThreadID = id; 9^ >M>f"  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 :M22P`:  
} fJ)N:q`  
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 JJ/1daj  
public void run() ,&.W6sW  
{ [F/^J|VMV  
while(nStartPos < nEndPos && !bStop) ;dqk@@O"(  
{ JQ)4}t  
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try{ >aEL;V=}P  
URL url = new URL(sURL); G3RrjWtO  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); dSOlD/c  
httpConnection.setRequestProperty("User-Agent","NetFox"); 6X@mPj[/  
String sProperty = "bytes="+nStartPos+"-"; 10C 2=  
httpConnection.setRequestProperty("RANGE",sProperty); ;YK!EMM4!h  
Utility.log(sProperty); Aautih@LX  
Q'Jv}'eK_  
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InputStream input = httpConnection.getInputStream(); 9z5"y|$  
//logResponseHead(httpConnection); ,c4c@|Bh?  
"El^38Ho  
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byte[] b = new byte[1024]; 8{R_6BS  
int nRead; Qs|OG  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) )
\{'fF  
{ IK*oFo{C=K  
nStartPos += fileAccessI.write(b,0,nRead); m"lE&AM64p  
//if(nThreadID == 1) UF@IBb}
0  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); #*!
+b  
} t*{,Gk  
![^EsgEB*  
%ZujCZn  
Utility.log("Thread " + nThreadID + " is over!"); _9D|u<D  
bDownOver = true; #|qm!aGs  
//nPos = fileAccessI.write (b,0,nRead); z^4KU\/JK  
} FE/$(7rM  
catch(Exception e){e.printStackTrace ();} zuUT S[  
} i]it5  
} <=q*N;=T,  
puFXPw.3  
+
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//打印回应的头信息 G1}~.%J  
public void logResponseHead(HttpURLConnection con) ?VFM]hO  
{ w[ Axs8N'  
for(int i=1;;i++) ,LhEshf  
{ -#hK|1]  
String header=con.getHeaderFieldKey(i); Q]< (bD.7  
if(header!=null) +"'F B
e  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); y^2#9\}K  
Utility.log(header+" : "+con.getHeaderField(header)); tf4*R_6;1$  
else ecn}
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break; :/+>e IE  
} 2 9q?$V(  
} >&bv\R/  
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public void splitterStop() \X&]FZ(*  
{ @u,+F0Yd  
bStop = true; KwS`3 6:  
} zQ,f5x  
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} egfi;8]E  
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/* GGH;Z WSe  
**FileAccess.java 8KFj<N>'  
*//文件访问(定位，写) hQXxG/yFm  
package NetFox; P3G:th@j=  
import java.io.*; aSUsy
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l1&5uwuF  
DL,[k (  
public class FileAccessI implements Serializable{ |VK:2p^ u  
|V lMmaz  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 8=:A/47=J  
RandomAccessFile oSavedFile; AWO0NWTB  
long nPos; PC|'yAN:  
C5Xof|#p|  
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public FileAccessI() throws IOException ?4,@, ae&  
{ sH%&+4!3  
this("",0); s}wO7Df=+  
} :AZp}  
$57\u/(  
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public FileAccessI(String sName,long nPos) throws IOException T)8p:}P!  
{ ' PELf P8  
oSavedFile = new RandomAccessFile(sName,"rw"); >)LAjwhBp  
this.nPos = nPos; 
u*hH}  
oSavedFile.seek(nPos); d<#p %$A4  
} QO2Ut!Y  
0C]4~F x~  
o5P&JBX<  
public synchronized int write(byte[] b,int nStart,int nLen) 3Y`>
6A=  
{ zO%w_7w  
int n = -1; :<|Z.4}kJb  
try{ [UoqIU  
oSavedFile.write(b,nStart,nLen); Rs2-94$!5  
n = nLen; M+0x;53nz  
} wazP,9W?  
catch(IOException e) Wm(:P  
{ 6+iK!&+=  
e.printStackTrace (); n'yl)HA~>`  
} #7o0dE;Kg9  
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return n; YZ< NP  
} 7aQn;  
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:9`qogF>  
} 4`s)ue  
`y2ljIWJ  
\#++s&06  
/* 3w6&&R9  
**SiteInfoBean.java X'@'/[?  
*/ *Rq`*D>:U}  
package NetFox; 3T1P$E" m  
+C_*Vs@4  
RyuEHpN}  
public class SiteInfoBean { t@)my[!  
8"i/wMP]  
ENq"mwV|  
private String sSiteURL; //Site's URL r{S=Z~J  
private String sFilePath; //Saved File's Path =UNT.]  
private String sFileName; //Saved File's Name )pS8{c)E  
private int nSplitter; //Count of Splited Downloading File g2=}G<*0  
\-OC|\{32  
D"cKlp-I6|  
public SiteInfoBean() Z(HZB
  
{//nSplitter的缺省值为5 D-pX<0-y  
//default value of nSplitter is 5 >! oF0R_<  
this("","","",5); cz#_<8'N  
} Fj^AWv^/  
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vL$|9|W(  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter)  %}h`+L  
{ "y$ qrN-  
sSiteURL= sURL; ^wJEfac  
sFilePath = sPath; )|RZa|`-G  
sFileName = sName; f&c]LH_  
this.nSplitter = nSpiltter; vU}: U)S  
$6!iBX@  
`VZZ^K9zR  
} C`0%C7  
|{f~Ks%  
VjB*{,  
public String getSSiteURL() #h N.=~  
{ .!yq@Q|=u  
return sSiteURL; 4fty~0i=z  
} DWrb
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]_u`EvEx6  
Fg=v6j4W  
public void setSSiteURL(String value) o@3B(j;J`  
{ /UHp [yod  
sSiteURL = value;  eu9w|g  
} Rg&19}BU  
-NzTqLBn
 
ZMdW2_*F   
public String getSFilePath() SA+d&H}Fc  
{ _CE9B e\  
return sFilePath; M/#U2!iFk  
} &z>q#'X;.  
O>AFF@=  
Pq?*C;D  
public void setSFilePath(String value) v9rVpYc"  
{ Q#pnj thM  
sFilePath = value; h<% U["   
} dIJGB==  
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C3}Aq8$6  
public String getSFileName() Dtt-|_EMS  
{ X*O9JGh  
return sFileName; N09KVz2Q  
} >vVw!.fJ  
-:SIS`0s  
El (/em  
public void setSFileName(String value) 8l23%iWxe  
{ JZ=5Bpw  
sFileName = value; {ma;G[!  
} GV8)Kor%  
kA^A mfba  
a,n93-m(m  
public int getNSplitter() jNc<~{/  
{ GNU;jSh5  
return nSplitter; $.:3$et@/  
} sPCMckt  
|>2:eH  
)gXTRkmw  
public void setNSplitter(int nCount) _~A~+S}  
{
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nSplitter = nCount; A1-qtAO]  
} ZEGd4_ux  
} /{X_ .fv<v  
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cZi[(
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/* w>vH8f  
**Utility.java KlUqoJ;"  
*/ d#\W hRE  
package NetFox; "2;N2=~7  
x=,8[W#XT  
0H[LS  
public class Utility { T~J?AKx  
]l[2hy= cV  
?9e]   
public Utility() }bMWTT  
{ 2xTT)9Tq*  
IN^_BKQt  
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} uV~e|X "9s  
:woa&(wN;1  
//线程睡眠 _M5Xk?e=  
public static void sleep(int nSecond) ;|TT(P:d  
{ K@r*;T  
try{  %+wF"  
Thread.sleep(nSecond); hhmGv9P  
} 2-v\3voN  
catch(Exception e) RH1uVdJ1  
{ YwAnqAg  
e.printStackTrace (); kon=il<@  
} Ei~f`{i  
} QlD6i-a  
7lU.Nit  
//日志 ow.j+<M  
public static void log(String sMsg) oT3Y!Y3=<  
{ ` X}85  
System.err.println(sMsg); / Z!i;@Wf  
} o:UXPAj  
/2@["*^$  
|4Ha?W  
public static void log(int sMsg) &71e5<(dG  
{ (F8AL6  
System.err.println(sMsg); {oWsh)[x2  
} c_1/W{  
} sX:lE^)-z  
XnXb&@Y  
!Iq{ 5:  
/* Wsm`YLYkt!  
**TestMethod.java bGv4.:)  
*/ p4>,Fwy2  
package NetFox; Qb`C)Nh:  
-3hCiKq  
Hr }k5'  
public class TestMethod { ow.6!tl0=h  
m mw-a0  
Q6^
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public TestMethod() >n!ni(  
{ ///xx/weblogic60b2_win.exe ~HDdO3  
try{ Np)aS[9W  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); dWR1cvB(wY  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); HomN/wKh  
SiteFileFetch fileFetch = new SiteFileFetch(bean); i&Kz*,pt  
fileFetch.start(); $(q8y/,R*-  
} G;]:$J  
catch(Exception e){e.printStackTrace ();} _N'75  
)|]Z>>%t  
@2' %o<lF  
} (ZPXdr  
7ZFJexN]  
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public static void main(String[] args) TnE+[.Qu  
{ &KqVN]1+^  
new TestMethod(); ^M|K;jt>  
} oJY[{-qW  
} #@Y/{[s|@  
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