http断点续传简单实现（java)

/* ,9C~%c0Pw  
**SiteFileFetch.java U<*8KiI  
*/ @N-P[.qL"  
package NetFox; %fyah}=  
import java.io.*; O*ql!9}E{  
import java.net.*; C;6N
u W  
%;r0,lN|II  
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public class SiteFileFetch extends Thread { z[I3k  
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SiteInfoBean siteInfoBean = null; //文件信息Bean -Pr1
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long[] nStartPos; //开始位置 K; +w'/{  
long[] nEndPos; //结束位置 &ZRriqsQg  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 .ZB(!v/2  
long nFileLength; //文件长度 /Y>$w$S  
boolean bFirst = true; //是否第一次取文件 ;ss,x  
boolean bStop = false; //停止标志 =
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File tmpFile; //文件下载的临时信息 FKOTv2  
DataOutputStream output; //输出到文件的输出流 V4PV@{G  
O{^ET:K@  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ^rmcyy8;g  
public SiteFileFetch(SiteInfoBean bean) throws IOException QD6in>+B@  
{ P@m_tA%  
siteInfoBean = bean; 3:XF7T  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); YQ&Ww|xe  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); !5hNG('f  
if(tmpFile.exists ()) INd:_cT4l  
{ 8+>r!)Q+  
bFirst = false; SpM|b5c5  
read_nPos(); LovVJ^TD0i  
} zJH#J=O  
else Y-Zw'  
{ [f^:V:){  
nStartPos = new long[bean.getNSplitter()]; dOm@cs  
nEndPos = new long[bean.getNSplitter()]; )<?^~"h  
} F ka^0  
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} /E/Z0<l7  
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public void run() y_>l'{w3^  
{ n#2tFuPE  
//获得文件长度 ^~3u|u  
//分割文件 @B@`V F  
//实例FileSplitterFetch "Cj{Z@n  
//启动FileSplitterFetch线程 &tNnW  
//等待子线程返回 )Vn(J#s
 
try{  }de{-  
if(bFirst) Yq6e=?-  
{ <sALA~p|0  
nFileLength = getFileSize(); 7Rba@ cs9  
if(nFileLength == -1) Xjy5
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{ U?bQBHIC  
System.err.println("File Length is not known!"); PQu_]cXI  
} E%[2NsOM]  
else if(nFileLength == -2) Hwz.5hV"  
{ <}\!FuC  
System.err.println("File is not access!"); V<:)bG4;d  
} F9Hxqa#1T  
else St1Ny,$yU  
{ >@g+%K]  
for(int i=0;i<nStartPos.length;i++) HX;JO[0  
{ '7oW
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); ;p/
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} S%^*h{9u"  
for(int i=0;i<nEndPos.length-1;i++) ~t>i+{JKE  
{ LU-,B?1  
nEndPos = nStartPos[i+1]; ]4uY<9VL  
} Q7!";ol2  
nEndPos[nEndPos.length-1] = nFileLength; &>@  
} "^Ax}Jr  
} L[D<e?j  
e5}KzFZmZ  
IO@Ti(,  
//启动子线程 z]twh&^1L  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 33M10 1X{6  
for(int i=0;i<nStartPos.length;i++) z0jF.ub  
{ tL#]G?0d  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), CDT%/9+-  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), pzQWr*5a  
nStartPos,nEndPos,i); nNEIwlj;  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 'm4v)w<y#  
fileSplitterFetch.start(); sTb@nrRxH  
} ~jpdDV&u\  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Dcep^8'  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); q-3e^-S*  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ?BEO(;'  
nEndPos = " + nFileLength); G
@N-+  
// fileSplitterFetch[nPos.length-1].start(); smJ#.I6/L  
~Pm[Ud  
;bMmJ>[l-  
//等待子线程结束 ju8DmC5  
//int count = 0; ng-rvr  
//是否结束while循环 |EjMpRNE  
boolean breakWhile = false; 79bt%P  
H!
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while(!bStop) !D!1%@ e  
{ P'Gf7sQt7  
write_nPos(); RHIGNzSz  
Utility.sleep(500); 'Cp]Q@]\  
breakWhile = true; PX$_."WA  
Yo^9Y@WDW  
*@-a{T}  
for(int i=0;i<nStartPos.length;i++) AnD#k
]  
{ # VAL\Z  
if(!fileSplitterFetch.bDownOver) iuGly~  
{ 8ED}!;ZU  
breakWhile = false; Es^=&2''  
break; Q\qI+F2?  
} 5_yu4{@;y  
} Z<4Du  
if(breakWhile) +W}dO#  
break; 4*Y`Pn@  
z<~yns`Y.  
w dpd`  
//count++; f8vWN  
//if(count>4) *_,: &Ur  
// siteStop(); Ce.*yO<-  
} pLtAusx  
hVLVMqd  
0V!@*Z  
System.err.println("文件下载结束！"); 3$#=*Zp  
} Pgh)+>ON  
catch(Exception e){e.printStackTrace ();} '1NZSiv+C?  
} T{B\1|2w  
mzH3Q564  
zYZ^/7)  
//获得文件长度 _uQxrB"9  
public long getFileSize() +h?Rb3=S  
{ G$7!/O%#_  
int nFileLength = -1; e00s*LdC  
try{ u7G9 eN  
URL url = new URL(siteInfoBean.getSSiteURL()); d:GAa   
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 7a5G,C#QQ  
httpConnection.setRequestProperty("User-Agent","NetFox"); 9zac[tno  
'joE-{  
vWq/A.  
int responseCode=httpConnection.getResponseCode(); ~z&H
o  
if(responseCode>=400) yTpvKCC  
{ ^QbaMX  
processErrorCode(responseCode); bG&vCH;}%  
return -2; //-2 represent access is error cjyb:gAO  
} :(Uz`k7   
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String sHeader; snti*e4"V  
aX,ux9#  
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for(int i=1;;i++) F?.J1]  
{ m[E#$JZtG  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ?CHFy2%Y  
//Utility.log(in.readLine()); \L4+Dv<z  
sHeader=httpConnection.getHeaderFieldKey(i); >#8J@=iuqv  
if(sHeader!=null) GJP\vsaQ  
{ +8eW/Bs@2  
if(sHeader.equals("Content-Length")) +E8}5pDt  
{ kf>L  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); [>xGynU0  
break; O}cg1Q8p  
} BzyzOtBp3L  
} +~cW0z  
else +t`QHvxv  
break; UCDvN  
} & GM&,  
} zyF[I6Gs  
catch(IOException e){e.printStackTrace ();} `|
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catch(Exception e){e.printStackTrace ();} ?>
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Utility.log(nFileLength); -YfpfNt  
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return nFileLength; ?Rg8u  
} B}A7Usm  
Bvy(vc=UDW  
q"%;),@  
//保存下载信息（文件指针位置） "i3Q)$"S  
private void write_nPos() FdVWj 5 $a  
{ 1> wt  
try{ r-SQk>Y}  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 2 bQC2  
output.writeInt(nStartPos.length); ee5QZ,  
for(int i=0;i<nStartPos.length;i++) EPMdR6
6  
{ ? 
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// output.writeLong(nPos); TRSR5D[  
output.writeLong(fileSplitterFetch.nStartPos); Tr@}  
output.writeLong(fileSplitterFetch.nEndPos); a|\ZC\(xI  
} I%q&4L7pj  
output.close(); Mb#-I GZ  
} j)[ wX  
catch(IOException e){e.printStackTrace ();} 4lqowg0  
catch(Exception e){e.printStackTrace ();} WF{rrU:  
} V/jEMJNks  
]/y&5X  
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//读取保存的下载信息（文件指针位置） (!^(74  
private void read_nPos() WV'FW)%  
{ <Hq|<^_K  
try{ M6+_Mi.  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); L*VO2YI  
int nCount = input.readInt(); f/:XIG  
nStartPos = new long[nCount]; %kg%ttu7  
nEndPos = new long[nCount]; !a[1rQH  
for(int i=0;i<nStartPos.length;i++) ^dzg'6M  
{ JRC+>'}Xj  
nStartPos = input.readLong(); i-b++R/WN  
nEndPos = input.readLong(); b]NSCu*)s  
} @qfVt  
input.close(); }cL9`a9j  
} :(|;J<R%_  
catch(IOException e){e.printStackTrace ();} n~#%>C
7  
catch(Exception e){e.printStackTrace ();} x_JCH7-  
} L.[ H   
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private void processErrorCode(int nErrorCode) CE$c/d[N.  
{ R^.oM1qu|  
System.err.println("Error Code : " + nErrorCode); 24)3^1P\V  
} (o1*7_]e  
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%r0yBK2uOp  
//停止文件下载 _91g=pM   
public void siteStop() Bf;dp`(/
 
{ n# %mL<  
bStop = true; 3%]%c6  
for(int i=0;i<nStartPos.length;i++) d7y`AS@q6  
fileSplitterFetch.splitterStop(); gL(ny/Ob9  
?v>!wuiP  
l
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} 2Y)3Ue  
} *7Ct#GC  
//负责部分文件的抓取 +s:!\(BM  
**FileSplitterFetch.java }@Ij}Ab>  
*/ a W`q  
package NetFox; _-&\~w  
~Cx07I_lf  
YK/?~p9:  
import java.io.*; |hjm^{!TpW  
import java.net.*; ~n$VCLa  
$ZD1_sJ.  
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public class FileSplitterFetch extends Thread { :A\8#]3  
~a:0Q{>a  
r^
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String sURL; //File URL 8,pnm  
long nStartPos; //File Snippet Start Position hBf0kl  
long nEndPos; //File Snippet End Position l+'@y (}Q  
int nThreadID; //Thread's ID K14e"w%6rs  
boolean bDownOver = false; //Downing is over <FIc!  
boolean bStop = false; //Stop identical Gpws_jw  
FileAccessI fileAccessI = null; //File Access interface 2r2qZ#I}  
QAigbSn]  
`Ym7XF&  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException epsh&)5a*  
{ Q# w`ZQX3  
this.sURL = sURL; |*5Kfxq  
this.nStartPos = nStart; ?(el6J}  
this.nEndPos = nEnd; %|$h<~  
nThreadID = id; tCAh?nR  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 k{<]J5{7  
} f"zXiUV  
&v7$*n27  
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public void run() :?%$
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{ Hn5:*;N  
while(nStartPos < nEndPos && !bStop) l2"{uCcA  
{ +jePp_3$O  
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try{ ld8E!t[  
URL url = new URL(sURL); {<{ O!  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); !63
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httpConnection.setRequestProperty("User-Agent","NetFox"); 7U>Xi'?  
String sProperty = "bytes="+nStartPos+"-"; tLXwszR0r  
httpConnection.setRequestProperty("RANGE",sProperty); ;uj&j1  
Utility.log(sProperty); QFMR~6 ?  
C?jk#T  
>58N P1[k  
InputStream input = httpConnection.getInputStream(); j+He8w-4  
//logResponseHead(httpConnection); <rZ(B>$  
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9P;}P!W  
byte[] b = new byte[1024]; S)T]>Ash  
int nRead; { O+d7,C  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) @
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{ r>4HF"Nm  
nStartPos += fileAccessI.write(b,0,nRead); h+)XLs  
//if(nThreadID == 1) TbqH-R3W  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); o$]wd*+  
} (_h<<`@B  
C7#ji"t  
b^[Ab:`}[V  
Utility.log("Thread " + nThreadID + " is over!"); ~.99H  
bDownOver = true; qPeaSv]W  
//nPos = fileAccessI.write (b,0,nRead); u;f${Wn'3  
} @X@?jj&  
catch(Exception e){e.printStackTrace ();} wVU.j$+_#  
} -FRMal4Pg0  
} :.wR*E  
mw2/jA7  
]X y2km]  
//打印回应的头信息 q1!45a  
public void logResponseHead(HttpURLConnection con) W^{zlg  
{ Ws%@SK  
for(int i=1;;i++) Dv~W!T i  
{ 0LEJnl  
String header=con.getHeaderFieldKey(i); 84g$V}mp  
if(header!=null) \)KLm  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); RCM;k;@8V  
Utility.log(header+" : "+con.getHeaderField(header)); 1vKAJ<4W  
else FXMrD,qVg  
break; Qh*"B  
} En01LrC?  
} {m%]`0
 
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zh8\ _>+  
public void splitterStop() +9LIpU&5  
{ HK_Vk\e  
bStop = true; = BcKWC  
} []^fb,5a  
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} S7i,oP7  
8EbJ5wu/%S  
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/* 'cp
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**FileAccess.java CK[w0VCT  
*//文件访问(定位，写) ,#n$YT7  
package NetFox; N@}5Fnk-  
import java.io.*; EWz,K]_'  
1eod;^AP9  
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public class FileAccessI implements Serializable{ i2bkgyzB.  
Xy(8}  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 `Hlv*" w$  
RandomAccessFile oSavedFile; ZC7ZlL_  
long nPos; $2!|e,x  
;t6)(d4z?  
}EJAC*W,  
public FileAccessI() throws IOException |
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{ b}&2j3-n,  
this("",0); 4~8!3JH39  
} Dk^,iY(u  
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E4}MU}C#[  
public FileAccessI(String sName,long nPos) throws IOException E^ub8  
{ 0c{-$K}  
oSavedFile = new RandomAccessFile(sName,"rw"); A^L8"  
this.nPos = nPos; Y8i'=Po%,  
oSavedFile.seek(nPos); 9Rf})$o+  
} @%"+;D  
3lh^maQ]  
L0^rw|Z%'  
public synchronized int write(byte[] b,int nStart,int nLen) Nw3K@Ge  
{ [hh
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int n = -1; ve3-GWT{C  
try{ PiL[&_8g  
oSavedFile.write(b,nStart,nLen); Hl|EySno  
n = nLen; -F->l5  
} cc0e(\  
catch(IOException e) v35!? 5{  
{ gdj,e ^  
e.printStackTrace (); :,8eM{.Q  
} E]MyP=g$  
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return n; ]K<mkUpY  
} Xi  8rD"v  
;rvZ!/  
(Zi,~Wqm$  
} U"T>L  
s[dq-pc"  
+.3,(l  
/* a_V.mu6h6p  
**SiteInfoBean.java K?J?]VCw  
*/ f.e4 C,  
package NetFox; sjW;Nsp  
*K#Ci1Q  
bnZ`Wc*5b  
public class SiteInfoBean { _~}n(?>  
}f;cA  
&sA@!  
private String sSiteURL; //Site's URL Y^(Nz
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private String sFilePath; //Saved File's Path 35}]U=  
private String sFileName; //Saved File's Name <jz\U7TBf  
private int nSplitter; //Count of Splited Downloading File ?S2!'L  
{Gi:W/jJ  
b^dBX  
public SiteInfoBean() 9zKbzT]  
{//nSplitter的缺省值为5  K0 6 E:  
//default value of nSplitter is 5 Om,M8!E  
this("","","",5); 5^0K5R6GQf  
} #J w\pOn  
#Zq[.9!q{  
\X]  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) VT:m!<^  
{ b&g`AnYT  
sSiteURL= sURL; kN8?.V%Utw  
sFilePath = sPath; x7!YA>  
sFileName = sName; m&I5~kD  
this.nSplitter = nSpiltter; q% pjY  
/4{.J=R}  
egHvI&w"o  
} n[c/L8j  
&{=`g+4n  
V|T3blG?D  
public String getSSiteURL() uc?`,;8{`  
{ p}K\rpvJpu  
return sSiteURL; $ 0
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} s9.nU  
<x->
.R_  
:/6gGU>pu  
public void setSSiteURL(String value) dt1,!sHn  
{ )K>2  
sSiteURL = value; =5D@~?W ZG  
} Z.{r%W{2  
"v[?`<53^l  
-MTO=#5z  
public String getSFilePath() r4wnfy  
{ _VFL}<i  
return sFilePath; Z#_+yw  
} (cpaMn@)g  
cuUlr  
noSBwP|v*  
public void setSFilePath(String value) bqI| wGCA"  
{ ?]Z EK8c  
sFilePath = value; O ]Stf7]%;  
} O~u@J'4  
'boAv%1_sa  
RxrUnM
F  
public String getSFileName() c ;@k\6  
{ YA'_Ba(v)  
return sFileName; `mo>~c7  
} w@Gk#  
:d`8:gv?  
KGq4tlM6  
public void setSFileName(String value) bR&<vrMmrA  
{ F
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sFileName = value; F3,djZq  
} dq U.2~9  
*JmU",X  
<Q%:c4N  
public int getNSplitter() ?
[~)D}] j  
{ v>]^wH>/"  
return nSplitter; N \Wd0b  
} W*D].|  
ypA)G/;  
NX5NE2@^qH  
public void setNSplitter(int nCount) AfOq?V  
{ ?&>H^}gDZ  
nSplitter = nCount; }y P98N5o  
} /{7we$+,p  
} AYLCdCoK.  
 l6uUS  
K-f\nr  
/* q1O}dSPwX  
**Utility.java VN[i;4o:|  
*/ .jps6{  
package NetFox; 3NA G}S  
*iW$>Yjb  
M!E#T-)  
public class Utility { |Je+y;P7  
M_monj}Z  
eOI#T'
5  
public Utility() cojbuo  
{ 8OW504AD  
h1uD>heGl  
xB&6f")  
} JHCV7$RS  
lS:R##  
//线程睡眠 $xsmF?Dsx5  
public static void sleep(int nSecond) {x8UL7{  
{ bAl0z)p
 
try{ %=O$@.%Zc  
Thread.sleep(nSecond); HxmCKW
!  
} YvP u%=eF  
catch(Exception e) /|. |y S9  
{ _Mis-K:]{?  
e.printStackTrace (); Fo1|O&>  
} mlmXFEC  
} 1n86Mp1.e  
$EuWQq7OI2  
//日志 {=Ku9\  
public static void log(String sMsg) v8L&F9 o  
{ +v}R-gNR  
System.err.println(sMsg); (KDv>@5  
} w'b|*_Q4Q  
xp>p#c  
95G*i;E  
public static void log(int sMsg) 9ywPWT[^  
{ .+"SDtoX  
System.err.println(sMsg); T'TxC)  
} s`$px2Gw  
} vs)1Rm  
@Fl&@ $  
cKj6tT"=O  
/* [Bz'c1  
**TestMethod.java uPtHC
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*/ sa71Vh{  
package NetFox; &2!F:L  
.7nr:P  
W2a9P_  
public class TestMethod { XU}sbbwu  
]GS@ub  
.2jG~_W[  
public TestMethod() pSq3\#Twr  
{ ///xx/weblogic60b2_win.exe )n[ oP%  
try{ GAlAFsB  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 5^\f[}  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); rl,6ru  
SiteFileFetch fileFetch = new SiteFileFetch(bean); :_qgpE<  
fileFetch.start(); >Tm|}\qEb  
} zJfoU*G/B  
catch(Exception e){e.printStackTrace ();} TZ7{cekQ  
 t: =  
Q.Kr;64G  
} srN>pO8u~  
#6tb{ws3  
ly d[GfJ  
public static void main(String[] args) ;5P>R[p  
{ tN5brf  
new TestMethod(); Rp2~d  
} FJN,er~T[  
} !
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