http断点续传简单实现（java)

/* K3Sa6"U  
**SiteFileFetch.java hXAgT!ZD  
*/  L- '{
  
package NetFox; k vuSE  
import java.io.*; pqT+lai)#  
import java.net.*; ]3KMFV}  
hRU5CH/!  
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public class SiteFileFetch extends Thread { CjQ)Bu*
4  
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SiteInfoBean siteInfoBean = null; //文件信息Bean (GCeD-  
long[] nStartPos; //开始位置 e>zv+9'Q  
long[] nEndPos; //结束位置 Wx8oTN  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Z&Qz"V>$  
long nFileLength; //文件长度 Y5/SbQYf1  
boolean bFirst = true; //是否第一次取文件 Y^Y1re+}  
boolean bStop = false; //停止标志 w'r?)WW$  
File tmpFile; //文件下载的临时信息 /%9Ge AAs  
DataOutputStream output; //输出到文件的输出流 Xn%ty@8  
H{d;,KfX  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） #9/^)^k  
public SiteFileFetch(SiteInfoBean bean) throws IOException 7]8nW!h;  
{ Y3
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siteInfoBean = bean; ZFxa2J~;  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 7{BTtUMAC  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); &^7^7:Y=?  
if(tmpFile.exists ()) Yk^clCB{A(  
{ lSG"c+iV  
bFirst = false; W5SCm(QS5  
read_nPos(); vyA `Z1  
} Gi+ZI{)  
else W2`/z)[*>  
{ yKhN1kY  
nStartPos = new long[bean.getNSplitter()]; 2=%R>&]*  
nEndPos = new long[bean.getNSplitter()]; )IFFtU~,  
} Cu $mb}@  
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} F,.dC&B
 
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public void run() uD0<|At/  
{ i]
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//获得文件长度 >qL-a*w:a  
//分割文件 j*fs [4  
//实例FileSplitterFetch H[DBL  
//启动FileSplitterFetch线程 [-p?gyl  
//等待子线程返回 Z(|'zAb^  
try{ IQ]tcSQl  
if(bFirst) sy(8-zbI  
{ L60Sc  
nFileLength = getFileSize(); +oRBSAg-  
if(nFileLength == -1) s#* DY  
{ %+bw2;a6  
System.err.println("File Length is not known!"); - %'ys  
} F8pP(Wl  
else if(nFileLength == -2) \:5M
0  
{ =U`9_]~1c@  
System.err.println("File is not access!"); R^f-j-$o]  
} \1MMz Z4rf  
else oD8X]R, H  
{ .kqH}{hf  
for(int i=0;i<nStartPos.length;i++) T*"*##c  
{ 7i##g,  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); LDgGVl  
} Oh'C[  
for(int i=0;i<nEndPos.length-1;i++) 6V&HlJH  
{ [rO TWN  
nEndPos = nStartPos[i+1]; rYfN  
} y{#9&ct&  
nEndPos[nEndPos.length-1] = nFileLength; \\(3gB.Gd  
} HxnWM\p  
} sMDHg
 
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//启动子线程 -V
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; \(4kEB2s$  
for(int i=0;i<nStartPos.length;i++) @\?QZX(H  
{ "~,3gNTzV  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Mrly(*!U"@  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), sIz*r Gz  
nStartPos,nEndPos,i); E5.@=U,c  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); tg"NWp6  
fileSplitterFetch.start(); G|+naZ  
} yk0#byW`  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), SLjSNuOP  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); (
> VD#n  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 5tUN'KEbN  
nEndPos = " + nFileLength); 7\<}378/^  
// fileSplitterFetch[nPos.length-1].start(); HlgkW&}c^  
caD|*.b  
f}ES8Hh[  
//等待子线程结束 +2 x|j>  
//int count = 0; aTi,gJ;*  
//是否结束while循环 7blo<|9  
boolean breakWhile = false; 4iC=+YUn  
d3&l!DoX  
kNC]q,ljt5  
while(!bStop) Z9p`78kYyh  
{ *Hed^[sO  
write_nPos(); Rdj/n :  
Utility.sleep(500); oaGpqjBGQ  
breakWhile = true; qu+Zl1~$]  
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for(int i=0;i<nStartPos.length;i++) c0.? d]  
{ !McRtxq?~  
if(!fileSplitterFetch.bDownOver) Scz/2vNi`  
{ Z_WJgH2c  
breakWhile = false; 586lN22xM  
break; q6AL}9]9  
} z$b'y;k  
} )Q)H!yin  
if(breakWhile) $guaUe[x  
break; yN:U"]glC  
9^2l<4^Z  
]MaD7q>+R  
//count++; JL:\\JT.  
//if(count>4) ,cwjieM  
// siteStop(); cIB[D.  
} -esq]c%3  
Y8@TY?  
gK",D^6T*Y  
System.err.println("文件下载结束！"); m5kt O^EU  
} GI[XcK^*w  
catch(Exception e){e.printStackTrace ();} `\M}~  
} aC,?FWm  
,4Qct=%L_  
.:A&5Y-  
//获得文件长度 v7#`b}'W  
public long getFileSize() h%+6y  
{ O]-s(8Oo3  
int nFileLength = -1; x!;;;iS  
try{ $Y=xu2u)  
URL url = new URL(siteInfoBean.getSSiteURL()); `#y?:s]e  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Ojs^-R_  
httpConnection.setRequestProperty("User-Agent","NetFox"); >A*BRX"4C  
uK5 C-  
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int responseCode=httpConnection.getResponseCode(); i564<1`x  
if(responseCode>=400) h:~ 8WV|  
{ *jrQ-'<T  
processErrorCode(responseCode); +GFK!Pf  
return -2; //-2 represent access is error ^M7pCetjdW  
} Q'R*a(pm  
K/IG6s;Xj  
pGT?=/=*  
String sHeader; i+4!nf{K  
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for(int i=1;;i++) 6sz:rv}  
{ c]>LL(R-7)  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); #8sv*8&  
//Utility.log(in.readLine()); B4
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sHeader=httpConnection.getHeaderFieldKey(i); Qzq3{%^x_  
if(sHeader!=null) O0=}:HM  
{ Fh U*mAX)  
if(sHeader.equals("Content-Length")) WLA LXJ7  
{ atYe$Db  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); m=Fk  
break; XTS%:S  
} ?A2jj`N1x  
} hVf;{p &  
else P`]p&:  
break; q-R'5p\C?|  
} (^9dp[2  
} 2x<4&^  
catch(IOException e){e.printStackTrace ();} 0o_wy1O1,  
catch(Exception e){e.printStackTrace ();} xQ~N1Y2W  
4>}qdR1L4  
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Utility.log(nFileLength); R~!md  
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return nFileLength; U_61y;Q"  
} \+VQoB/  
#"KaRh  
F,/yK-9  
//保存下载信息（文件指针位置） %(i(Cf8@  
private void write_nPos() 1 TA\6a}  
{ 1`v$R0`!  
try{ 9ELRn@5.  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Io\tZXB  
output.writeInt(nStartPos.length); -H9WwFk  
for(int i=0;i<nStartPos.length;i++) u7}C):@H  
{ a1 .+L  
// output.writeLong(nPos); LR Dj!{k{  
output.writeLong(fileSplitterFetch.nStartPos); ' i<}/l  
output.writeLong(fileSplitterFetch.nEndPos); qJq!0F  
} <EM'|IR?  
output.close(); 2{I+H'w8:  
} rUWC=?Q  
catch(IOException e){e.printStackTrace ();} ^<w3i?KPW  
catch(Exception e){e.printStackTrace ();} {1m.d;(1  
} XO,gEn&6V  
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}4XXNYH  
//读取保存的下载信息（文件指针位置） _(0GAz%9  
private void read_nPos() B~7]x;8h  
{ WeE1 \  
try{ 141XnAb)I  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); st-I7K\v  
int nCount = input.readInt(); SPo}!&p$~  
nStartPos = new long[nCount]; P2=u-{?~  
nEndPos = new long[nCount]; ew 4pAav  
for(int i=0;i<nStartPos.length;i++) q:-1ul  
{ cC7&]2X +f  
nStartPos = input.readLong(); w i=&W  
nEndPos = input.readLong(); 1qd(3A41  
} d6+{^v$#  
input.close(); [$FiXH J  
} 4">
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catch(IOException e){e.printStackTrace ();} Jx
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catch(Exception e){e.printStackTrace ();} p$1y8Zbor  
} Mv7=ZAm  
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private void processErrorCode(int nErrorCode) NK$BF(HBi  
{ =At)
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System.err.println("Error Code : " + nErrorCode); "
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} .qD=u1{p9  
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//停止文件下载 
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public void siteStop() #!R=h|  
{ 3iBUIv  
bStop = true; ;noZmPa  
for(int i=0;i<nStartPos.length;i++) *!&,)
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fileSplitterFetch.splitterStop(); J[jzkzSu`  
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I.hy"y2&  
} }CB9H$FkCY  
} |P(8T'  
//负责部分文件的抓取 j5V{,lf  
**FileSplitterFetch.java WdJJt2'  
*/
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package NetFox; s]Qo'q
2  
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|rwx;+  
import java.io.*; ~xU\%@I\  
import java.net.*; m`6=6(_p  
3"p'WZ>  
]=?.LMjnH  
public class FileSplitterFetch extends Thread { :3.!?mOe2  
`i{p6-U3  
!X ={a{<,T  
String sURL; //File URL
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long nStartPos; //File Snippet Start Position c);vl%  
long nEndPos; //File Snippet End Position V6uh'2  
int nThreadID; //Thread's ID L#Rj~&U  
boolean bDownOver = false; //Downing is over 8
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boolean bStop = false; //Stop identical R&FO-{S  
FileAccessI fileAccessI = null; //File Access interface ^+rI=c 0  
S- JD}+9  
#?klVK&e/  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException yLEAbd%+  
{ Pm==m9  
this.sURL = sURL; H.#zbKj  
this.nStartPos = nStart; !A'3Mw\Nm  
this.nEndPos = nEnd; f=T&$tZ<  
nThreadID = id; NEff`mwm5)  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ?C*}NM  
}  wjfc9z  
VX]Ud\(  
)kvrQ6  
public void run() _<6B.{$\7m  
{ `=19iAp.  
while(nStartPos < nEndPos && !bStop) zr^"zcfz&  
{ E?cf#;2h8m  
Bz4;R9_%I  
;(Kj-,>  
try{ rB}2F*eT  
URL url = new URL(sURL); ^C70b)68  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); mae@L  
httpConnection.setRequestProperty("User-Agent","NetFox"); \.Z /  
String sProperty = "bytes="+nStartPos+"-"; n7(/ml+Q_  
httpConnection.setRequestProperty("RANGE",sProperty); ?#Y1E~N  
Utility.log(sProperty); "mB /"  
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bD
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InputStream input = httpConnection.getInputStream(); H-jxH,mJmW  
//logResponseHead(httpConnection); (Ky$(Ubb#6  
.'zcD^  
,)Z1&J?  
byte[] b = new byte[1024]; *Z2#U?_  
int nRead; +XpQ9Cd  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) !MEA@^$#  
{ cg_j.=M-  
nStartPos += fileAccessI.write(b,0,nRead); rHJtNN8$k  
//if(nThreadID == 1) (Z?g^kjq)  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Dgm"1+  
} (gjCm0#_%  
b0uWUI(=  
uy8mhB+]  
Utility.log("Thread " + nThreadID + " is over!"); !m6=Us  
bDownOver = true; s(cC;  
//nPos = fileAccessI.write (b,0,nRead); W ![*0pL  
} ?$~5ti#\  
catch(Exception e){e.printStackTrace ();} ^EcwY- Qr  
} 5;X3{$y  
} qv)%)n  
g [c^7  
67]!xy  
//打印回应的头信息 a}V
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public void logResponseHead(HttpURLConnection con) x/uC)xm  
{ O]80";Uv  
for(int i=1;;i++) Nbd[xs-lw  
{ sDP8!  
String header=con.getHeaderFieldKey(i); } bm ^`QY  
if(header!=null) .wf$]oQQ  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); =&#t("  
Utility.log(header+" : "+con.getHeaderField(header)); I\Pw`  
else M+-1/vR *@  
break; A?"/ >LM  
} m4,inA:o  
} l\HtP7]  
+%?\#EQJ  
Y} crE/  
public void splitterStop() \ k &ZA  
{ e,Sxu[2  
bStop = true; l^
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} Mu/hTTiNx  
]. 0;;v6)  
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} J Mm'JK?  
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C~R,,  
/* cHX~-:KOr  
**FileAccess.java 0`Y"xN`'i  
*//文件访问(定位，写) @o>3 Bv.  
package NetFox; #PQhgli  
import java.io.*; ky I~  
>DoP2]  
/-&2>4I  
public class FileAccessI implements Serializable{ ="P&!lu  
5#Et.P'  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 {~EPP .  
RandomAccessFile oSavedFile; 8SoTABHV  
long nPos; q+W*?a)  
U(5Yg  
4q*mEV  
public FileAccessI() throws IOException 5U6b\jxX  
{ Zqj EVVB  
this("",0); /7igPNhx  
} :I8HRkp  
G3j'A{  
VvTi>2(.  
public FileAccessI(String sName,long nPos) throws IOException ='Yg^:n  
{ |'](zEwq  
oSavedFile = new RandomAccessFile(sName,"rw"); MS;^@>|wj  
this.nPos = nPos; F?XiP.`DR  
oSavedFile.seek(nPos); qz8Jvgu?  
} W~Q;R:y  
oa6&?4K?F  
 _:HQ4s@  
public synchronized int write(byte[] b,int nStart,int nLen) 6xoCB/]  
{ 'Xu3]'m*  
int n = -1; j.+}Z |  
try{ ?63ep:Q
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oSavedFile.write(b,nStart,nLen); pMzlpmW;P  
n = nLen; Aaz2._:/-m  
} KN".0WU  
catch(IOException e) Bb.U4#  
{ liPaT  
e.printStackTrace (); +^ `n- m  
} JzmX~|=Xi  
<\oD4EE_  
X9;51JV  
return n; ;nAI;Qw L  
} Zx)gLDd  
}X~"RQf9  
fT.MglJcb  
} ^CW{`eBwk  
F[*/D/y(  
S#nW )=   
/* B!((N{4H+  
**SiteInfoBean.java "mc ]^O  
*/ o8fY!C)  
package NetFox; }A&
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%PC8}++  
nIGElt]  
public class SiteInfoBean { G{gc]7\=Cd  
_FkIg>s  
f"t+r /d  
private String sSiteURL; //Site's URL i0rh{Ko  
private String sFilePath; //Saved File's Path +!$]a^3l  
private String sFileName; //Saved File's Name "~L$oji  
private int nSplitter; //Count of Splited Downloading File dz1kQzOU*  
))4RgS$  
1t}  
public SiteInfoBean() "x O+  
{//nSplitter的缺省值为5 GrI<w.9X  
//default value of nSplitter is 5 czT]XF  
this("","","",5); >tE6^7B*  
} #,9#x]U#v  
qm< mw"]  
_ O;R  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) \`R8s_S  
{ Fb6d1I^wR  
sSiteURL= sURL; #~[{*[B+  
sFilePath = sPath; ^Vg-fO]V  
sFileName = sName; xB5QM #w\  
this.nSplitter = nSpiltter; u,./,:O%=  
#@J{ )  
$'3'[Nr(;t  
} v(p<88.!m  
A~H@0>1  
}!N/?A5  
public String getSSiteURL() p{AX"|QM"  
{ e'r-o~1eN  
return sSiteURL; !vq|*8  
} '<xV]k|v  
D+y?KihE  
Hz j%G>  
public void setSSiteURL(String value) cVli^*se  
{ DA>TT~L  
sSiteURL = value; v {)8QF]  
} CI=M0  
^.c<b_(=h  
~>XqR/v  
public String getSFilePath() NRazI_Z  
{ (Ta(Y=!uq  
return sFilePath; Wpc8T="q  
} Ll, U>yo  
X'j9l4Ph7  
i5SDy(?r  
public void setSFilePath(String value) _pxurq{  
{ 5]zH!>-F  
sFilePath = value; J~AmRo0!k  
} p# |} o9  
Sl'{rol'  
sY:=bU^P  
public String getSFileName() 4+MaV<!tU^  
{ M2I*_pI  
return sFileName; 3Scc"9]  
} TQth"Cv2:  
cp6I]#X  
\-
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public void setSFileName(String value) O=oIkvg  
{ j<
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sFileName = value; sfk;c#K  
} *!ecb1U5  
pA6A*~QE  
9I(00t_  
public int getNSplitter() Y]DC; ,  
{ mJYD"WgY
 
return nSplitter; kW=!RX[&  
} <==6fc>s  
gBOF#"-  
Hyi'z
1  
public void setNSplitter(int nCount) ?}#Iu
-IA  
{ g}pD%  
nSplitter = nCount; %e:[[yq)G  
} h4Xz"i{z  
} PJ\k|
 
} L_Zmi$  
\\;y W~  
/* [_: GQ  
**Utility.java /0Mt-8[  
*/ yW&ka3j
\  
package NetFox; [Y.=bfV!  
""*g\  
,c&gw tdl  
public class Utility { ^I)+u>fJ  
^0-e.@  
]n3!%0]\  
public Utility() 28vQ  
{ =_CH$F!U  
q
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wF3 MzN=%  
} r"|.`$:B  
C[5dhFZ  
//线程睡眠 ^PUB~P/  
public static void sleep(int nSecond) 3-'3w,  
{ Jhfw$DF  
try{ E6z&pM8<8  
Thread.sleep(nSecond); (T%Ue2zlY  
} k5Su&e4]]  
catch(Exception e) s6'=4gM  
{
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e.printStackTrace (); vM50
H
 
} Wb[k2V  
} Hg$7[um  
).AMfBQ=;  
//日志 "Q{l])N  
public static void log(String sMsg) | AiMx2  
{ t7Mq>rFB  
System.err.println(sMsg);  0T^0)c  
} )?pnV":2Y  
)j\_*SoH  
q@tym5  
public static void log(int sMsg) _07$TC1  
{ =3!o_  
System.err.println(sMsg); p$uPj*  
} |(AFU3~  
} 7iyx_gyo  
VJ?>o  
+bT[lJ2O>G  
/* T#wG]DH;  
**TestMethod.java Cc;8+Z=a?G  
*/ vPc*x5w-  
package NetFox; $HtGB]  
9Q!Z9n"8~)  
AyPtbrO  
public class TestMethod { @DF7j|]tV  
ZCViZWo  
64]8ykRD-  
public TestMethod() DEbMb6)U  
{ ///xx/weblogic60b2_win.exe `WnsM;1Y"  
try{ dFA1nn6{  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); sN2m?`?"G  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); x,zYNNx5g  
SiteFileFetch fileFetch = new SiteFileFetch(bean); @b,6W wc  
fileFetch.start(); lQBEq"7$  
} 7?{y&sf  
catch(Exception e){e.printStackTrace ();} /V63yzoY  
MTKNIv|  
k>7bPR5Mw  
} n1PBpM9!  
W6_rSVm  
 !Q*w]  
public static void main(String[] args) xVgm 9s$"c  
{ ]:b52Z  
new TestMethod(); b*H*(}A6"'  
} g7a446QR\K  
} +I3O/=)  
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