http断点续传简单实现（java)

/* ",&^ f  
**SiteFileFetch.java $wnK"k%G  
*/ haTmfh_|  
package NetFox; #GoZH?MAF  
import java.io.*; 7S^ba  
import java.net.*; wg-qq4Q\  
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public class SiteFileFetch extends Thread { ')G,+d^  
=17d7#-  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 04o>POR  
long[] nStartPos; //开始位置 w8(8n&5  
long[] nEndPos; //结束位置 jg)+]r/hS  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 3:H[S_q  
long nFileLength; //文件长度 Mk=
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boolean bFirst = true; //是否第一次取文件 r1pj-   
boolean bStop = false; //停止标志 {Sl#z}@s  
File tmpFile; //文件下载的临时信息 w^BF.Nu  
DataOutputStream output; //输出到文件的输出流 ML:Zm~A1U  
w?;j5[j  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ]{.iv_I  
public SiteFileFetch(SiteInfoBean bean) throws IOException  kD}w5 U  
{ ZwzN=03T  
siteInfoBean = bean; u4eA++eT  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); *P:!lO\|  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); /w|!SZB  
if(tmpFile.exists ()) 5)@UpcjUA  
{ q7#4e?1  
bFirst = false; o54/r#~fi  
read_nPos(); Yee% <<S  
} )c6t`SBwi  
else @XJzM]*w&  
{ 0pfgE=9  
nStartPos = new long[bean.getNSplitter()]; z*oeho  
nEndPos = new long[bean.getNSplitter()]; Xh5&J9pw   
} EOj.Jrs~  
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} (=\))t8J  
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public void run() -f&m4J} E  
{ #TUuk  
//获得文件长度 kq$0~lNI$  
//分割文件 )/:j$aq  
//实例FileSplitterFetch l b9O  
//启动FileSplitterFetch线程 > r %:!o  
//等待子线程返回 |XrGf2P9u  
try{ ow<z @^ 3'  
if(bFirst) q2{Aq[  
{ $wm.,Vb  
nFileLength = getFileSize(); ##QKXSD  
if(nFileLength == -1) .EfGL_  
{ /:=,mWoO  
System.err.println("File Length is not known!"); .wpp)M.w;H  
} .Ce0yAl~  
else if(nFileLength == -2) y$,j'B:;4m  
{ =".sCV9"N  
System.err.println("File is not access!"); q
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} #;(Q \  
else F'^y?UP[  
{ `Q1;Y  
for(int i=0;i<nStartPos.length;i++) h 7/wkv\y9  
{ ^[=1J  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); s +Q'\?  
} LLV1W0VO=P  
for(int i=0;i<nEndPos.length-1;i++) yhsbso,5 a  
{ <)]j;Tl  
nEndPos = nStartPos[i+1]; o4qB0h  
} .-mlV ^  
nEndPos[nEndPos.length-1] = nFileLength; Qd"R@+i  
} ^ZD0rp(l  
} 3?x}48  
9O{b8=\}  
V9\y*6#Y,  
//启动子线程 D/`b~Yl  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ?y|8bw<  
for(int i=0;i<nStartPos.length;i++) CkeqK  
{ |h 3`z  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), X-']D_f|,  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), +\GuZ5`  
nStartPos,nEndPos,i); ']^
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Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); +eVm+4WK  
fileSplitterFetch.start(); ":vF[6K6  
} 3bK=Q3N  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 8h{;*Wr-  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 1\LK[tvh  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", @tfatq+q  
nEndPos = " + nFileLength); /I@`B2  
// fileSplitterFetch[nPos.length-1].start(); Y{`hRz`  
*USzzLq  
XJguw/[wm  
//等待子线程结束 +rOfQ'lQ  
//int count = 0; Pm=i(TBS/  
//是否结束while循环 q+1SU6x'm  
boolean breakWhile = false; 52v@zDY  
A5 <T7~U  
nK>D& S_!  
while(!bStop) (@3?JJ]1  
{ hNL_e3  
write_nPos(); J]gtgt^   
Utility.sleep(500); ZK?:w^Z  
breakWhile = true; j=V2~ xA6  
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for(int i=0;i<nStartPos.length;i++) g7`uWAxZa  
{ lfe^_`ij(+  
if(!fileSplitterFetch.bDownOver) "*oN~&flc  
{ 'l41];_  
breakWhile = false; ;Ebpf J  
break; &^JYIRn1\  
} VCCG_
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} yiAusl;  
if(breakWhile) Zoyo:vv&  
break; n1@ Or=5  
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_/RP3"#  
//count++; ;o?Wn=J  
//if(count>4) l EsE]f  
// siteStop(); I%# e\  
} n,
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System.err.println("文件下载结束！"); Ku<_N]9  
} &k0c|q]  
catch(Exception e){e.printStackTrace ();} gt:Ot0\7  
} (IIOVv 1J  
=:pN82.G  
.,( ,<  
//获得文件长度 J>S`}p  
public long getFileSize() s[tFaB1  
{ ("rIz8b  
int nFileLength = -1; ~8^)[n+)x  
try{ * ~4m!U_s  
URL url = new URL(siteInfoBean.getSSiteURL()); -"X} )N2  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Rss=ihlM  
httpConnection.setRequestProperty("User-Agent","NetFox"); ko<VB#pOMr  
d){Al(/  
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int responseCode=httpConnection.getResponseCode(); GcA!I!j/  
if(responseCode>=400) WgC*bp{  
{ CJ 9tO#R  
processErrorCode(responseCode); ]J6+nA6)  
return -2; //-2 represent access is error bmu<V1[W  
} ,';+
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String sHeader; Mb[4G>-v=  
PdD|3B&  
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for(int i=1;;i++) H=k`7YN  
{ MB]Y|Vee  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ());  {r?qI  
//Utility.log(in.readLine()); )bPF@'rF2  
sHeader=httpConnection.getHeaderFieldKey(i); -"Q[n,"Y  
if(sHeader!=null) Y'S9   
{ #p^r)+\3=  
if(sHeader.equals("Content-Length")) g+iV0bbT  
{ !B\[Q$  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); QWWoj[d#  
break; gHzjI[WI  
} L7qlvS Q  
} R WU,v{I9  
else qnZ`]?  
break; ;o0o6pF  
} 7f`x-iH!]7  
} )gAFz+  
catch(IOException e){e.printStackTrace ();} w_ po47S4  
catch(Exception e){e.printStackTrace ();} m%?b"kxL[  
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Utility.log(nFileLength); _*w}"\4_  
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return nFileLength; xuDn:  
} e`Z3
{H}  
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1yIo'i1  
//保存下载信息（文件指针位置） 6uH1dsD  
private void write_nPos() 7J%v""\1!  
{ o ) FjWf;  
try{ FE/2.!]&o  
output = new DataOutputStream(new FileOutputStream(tmpFile)); y|+ltAK  
output.writeInt(nStartPos.length); Y;e
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for(int i=0;i<nStartPos.length;i++) ]Zf@NY  
{ xR,;^R|C  
// output.writeLong(nPos); R.)U<`||  
output.writeLong(fileSplitterFetch.nStartPos); SEXLi8;/  
output.writeLong(fileSplitterFetch.nEndPos); i#~1|2  
} ~Zd n#z\  
output.close(); r,4V SyZF\  
} tK|hC[  
catch(IOException e){e.printStackTrace ();} cMEM}Qh T  
catch(Exception e){e.printStackTrace ();} TIa`cU`  
} (u >:G6K  
].2it{gF?b  
= *A_{u;E  
//读取保存的下载信息（文件指针位置） rHtT>UE=  
private void read_nPos() "lf_`4  
{ ]41G!'E=  
try{ )LYj,do  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ab 1\nzpd  
int nCount = input.readInt(); N>Pufr  
nStartPos = new long[nCount]; \g}FoN&  
nEndPos = new long[nCount]; g/q$;cB  
for(int i=0;i<nStartPos.length;i++) EN%Xs578  
{ Te#wU e-|  
nStartPos = input.readLong(); ^IGTGY]s  
nEndPos = input.readLong(); +Hb6j02#  
} G\H@lFh  
input.close(); @$79$:q N  
} (t9qwSS8z  
catch(IOException e){e.printStackTrace ();} Tj{!Fx^H  
catch(Exception e){e.printStackTrace ();} 7,e=|%7.  
} *3
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private void processErrorCode(int nErrorCode) uu>[WFh  
{ f41!+W=  
System.err.println("Error Code : " + nErrorCode); 00G[`a5  
} QLH s 3eM  
`4&\ %9  
<!zItFMD[m  
//停止文件下载 +WwQ!vWWd  
public void siteStop() \Rp)n=|  
{ DrltxI)  
bStop = true; C_#0Y_O  
for(int i=0;i<nStartPos.length;i++) F ,{nG[PL  
fileSplitterFetch.splitterStop(); m`
9)DsR N  
%'* |N[  
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} vfegIoZ  
} |U^ ff^]  
//负责部分文件的抓取 2uWzcy ?F  
**FileSplitterFetch.java ,[bcyf  
*/ 'EREut,>'  
package NetFox; h3p 3~xq  
kQIWDN  
fINM$ 6  
import java.io.*; [-$&pB>w8'  
import java.net.*; $Y,]D*|"K  
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public class FileSplitterFetch extends Thread { U)p2PTfB  
{djOU 9]  
oT|E\wj  
String sURL; //File URL u(ZS sftat  
long nStartPos; //File Snippet Start Position 1"odkM  
long nEndPos; //File Snippet End Position BJj~fNm1Zr  
int nThreadID; //Thread's ID i}<R>]S  
boolean bDownOver = false; //Downing is over SsznV}{^  
boolean bStop = false; //Stop identical mk4%]t"  
FileAccessI fileAccessI = null; //File Access interface jd2Fh):q  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException rP`\<}a.  
{ u>S&?X'a  
this.sURL = sURL;  ]NAPvw#p  
this.nStartPos = nStart; O~,^x$ve  
this.nEndPos = nEnd; X\%],"9%  
nThreadID = id; \Y!Z3CK  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 {.,OPR"\  
} ydns_Z  
TTE#7\K~B  
+]]wf'w  
public void run() g'Xl>q  
{ 7FDraEr#f  
while(nStartPos < nEndPos && !bStop) T>uLqd{hH  
{ )cqhbR  
)edM@beY_  
}(tGjx]  
try{ Wt3\&.n  
URL url = new URL(sURL); 6!"15dPN  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ZTmdS  
httpConnection.setRequestProperty("User-Agent","NetFox"); Z@ws,f^e  
String sProperty = "bytes="+nStartPos+"-"; v8%]^` '  
httpConnection.setRequestProperty("RANGE",sProperty); i^IvT  
Utility.log(sProperty); cE*|8'rSf  
>M1/m=a  
pb{P[-f  
InputStream input = httpConnection.getInputStream(); _~cmR<  
//logResponseHead(httpConnection); VS).!;>z  
,OasT!Sr  
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byte[] b = new byte[1024]; E>g'!  
int nRead; "Z{^i3gN  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 5;^8wh(  
{
u%h<5WNh<  
nStartPos += fileAccessI.write(b,0,nRead); i5n'f6C  
//if(nThreadID == 1) lpp'.HTP  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 1QN]9R0`#7  
} R*[ACpxr  
J`mp8?;%  
cKfYkJ)A'  
Utility.log("Thread " + nThreadID + " is over!"); <K0lS;@K  
bDownOver = true; AjlG_F  
//nPos = fileAccessI.write (b,0,nRead); !c&^b@ yw  
} c"z%AzUV'  
catch(Exception e){e.printStackTrace ();} U=y
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} ZE
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} -Qgfo|po  
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7Ow7|  
//打印回应的头信息 =0:hrg+Zgx  
public void logResponseHead(HttpURLConnection con) S77Gc:[;8  
{ E+2y-B)E  
for(int i=1;;i++) Z~nl{P#  
{ };+s0:H  
String header=con.getHeaderFieldKey(i); zyR pHM$E  
if(header!=null) C}>&#)IH  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 5Ci}w|c/>  
Utility.log(header+" : "+con.getHeaderField(header)); zV&3l9?U  
else 9e=*jRs]l^  
break; PT4`1Oy}/1  
} 7RLh#D|  
} ]S[r$<r$  
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public void splitterStop() ec0v
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{ UEeqk"t^  
bStop = true; uJO
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} /Yh([P>  
Ya. $x~  
us cR/d  
} .Sn1YAhE  
f65Sr"qB3  
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/* Gt%ko
k  
**FileAccess.java 3edAI&a5  
*//文件访问(定位，写) =,'Z6?%p  
package NetFox; gMvvDP!Wp  
import java.io.*; lrE0)B5F  
M,@SUu v"  
CL*%06QyE  
public class FileAccessI implements Serializable{ '!I?C/49k  
at*
=#?M1?  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 (NQ[AypMI  
RandomAccessFile oSavedFile; e)7)~g54  
long nPos; cm3Y!p{p"  
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m)  
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public FileAccessI() throws IOException 3u^TJt)  
{ (wfg84  
this("",0); p\WUk@4  
} 7S`H?},sR  
VJ"3G;;  
~<%cc+;`  
public FileAccessI(String sName,long nPos) throws IOException U)!AH^{32  
{ 8if"U xV(  
oSavedFile = new RandomAccessFile(sName,"rw"); v(^rq  
this.nPos = nPos; ,54<U~Lg:  
oSavedFile.seek(nPos); Wg%-m%7O  
} t>fB
@xHBB  
{<2ZbN?  
|$t0cd  
public synchronized int write(byte[] b,int nStart,int nLen) =gIYa  
{ LTe7f8A  
int n = -1; w(j9[  
try{ =I(s7=Liu  
oSavedFile.write(b,nStart,nLen); hvyN8We  
n = nLen; 6&Dvp1`m  
}
a)1,/:7'  
catch(IOException e) b {5|2&=  
{ r2th6hl~  
e.printStackTrace (); Lk9>7xY  
} b{rmxtx  
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return n; CA4-&O"  
} + LwoBn>6  
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} bwJi[xF  
o zYI/b^  
]SL&x:/-  
/* l.x }I"tf  
**SiteInfoBean.java !iVFzG @m  
*/ )ta5y7np  
package NetFox; ([Aq  
ry ?2 o!  
@:&+wq_>A^  
public class SiteInfoBean { O[y`'z;C  
?/(K7>`  
b-?o?}*  
private String sSiteURL; //Site's URL kA
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private String sFilePath; //Saved File's Path ~@D%qbN  
private String sFileName; //Saved File's Name 6bcrPf}  
private int nSplitter; //Count of Splited Downloading File <.b$ gX  
|S{P`)z%f  
lF(!(>YZ  
public SiteInfoBean() Q/c WV  
{//nSplitter的缺省值为5 Wts{tb  
//default value of nSplitter is 5 `4bd,  
this("","","",5); shT[|@"C  
} >@U<?
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U  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) N o(f0g.  
{ 2.D!4+&  
sSiteURL= sURL; /8}+#h)[  
sFilePath = sPath; Ye2];(M  
sFileName = sName; V(u2{4gZ  
this.nSplitter = nSpiltter; C|\^uR0  
d~jtWd|?  
aT#{t{gkA  
} hPz df*(8  
{*;]I?9Al  
1gm/{w6O  
public String getSSiteURL() O&w3@9KJ?  
{ {@5WeWlz~  
return sSiteURL; cWO )QIE  
} @$d\5Q(G  
i\;&CzC:  
`E=rh3 L0o  
public void setSSiteURL(String value) cqY.^f.  
{ \>Rwg=Lh  
sSiteURL = value; .)>/!|i  
} N&APq
T  
sBtG}Mo)  
~'J 
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public String getSFilePath() LGROEn<*d  
{ P0ltN  
return sFilePath; )O@^H  
} !X%!7wsc  
5 ?~-Vv31s  
"42$AaS  
public void setSFilePath(String value) o U}t'WU  
{ 1qj%a%R  
sFilePath = value; >zg8xA1zL  
} &]6K]sWJK{  
(4ci=*3=  
J(0=~Z[  
public String getSFileName() a^c,=X3  
{ N~5WA3xd  
return sFileName; :F>L;mp  
} s.;KVy,=Bu  
G^rh*cb K  
l~4e2xoT  
public void setSFileName(String value) /;nO<X:XV  
{ N~}v:rK>g  
sFileName = value; V\K m% vP  
} n5k^v$'  
}gi1?a59  
"gN*J)!x  
public int getNSplitter() p (xD/E  
{ _jrA?pY  
return nSplitter; Z"~6yF  
} ,}IER  
P}+|`>L  
xUo)_P\_  
public void setNSplitter(int nCount) ys[i`~$  
{ |<3Q+EB^  
nSplitter = nCount; K;y\[2;}e,  
} b6!Q!:GO&  
} J4Z<Yt/  
k[ffs}  
:qCm71*  
/* x|v[Dxf]  
**Utility.java }8V;s-1  
*/ H]i+o6  
package NetFox; Iz?Wtm }  
p=-B~:  
%<=vbL9  
public class Utility { !v5sWVVR  
86[RH!e  
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public Utility() UQ$\ an'  
{ ;%rs{XO9  
oX2DFgz  
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} GrLM${G  
c(Uj'uLc  
//线程睡眠 U)`3[fo  
public static void sleep(int nSecond) cB|Cy{%
 
{ hDB
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try{ 7:VEM;[d  
Thread.sleep(nSecond); Xw*%3'  
} ;ad9{":J#B  
catch(Exception e) h2/dhp  
{ GwMUIevO_  
e.printStackTrace (); .}$`+h8WT  
} n^JUZ8  
} Pzk[^z$C  
MOp=9d+N~  
//日志 @dE 3  
public static void log(String sMsg) dS3>q<J*a  
{ o}mhy`}  
System.err.println(sMsg); xyS2_Q  
}
8V=HyF#  
v E3{H  
!X\sQNp  
public static void log(int sMsg) 0{"dI;b%  
{ } Jdh^t.  
System.err.println(sMsg); yRq8;@YGY  
}  u]1-h6  
} AF*ni~  
]xJ'oBhy  
^Kw&=u  
/* a8bX"#OR&N  
**TestMethod.java u,Q_WR-wJ  
*/ nj~$%vmA  
package NetFox; {hs2?#p  
, `[Z`SUk`  
Ypn%[sSOp  
public class TestMethod { >tmnj/=&   
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I5TQ>WJbf  
public TestMethod() u:Af
HZ  
{ ///xx/weblogic60b2_win.exe CzzUi]*Ac{  
try{ w| -0@  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); x%IXwP0  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 5A2Y'ms,/  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 0,1L e$)6  
fileFetch.start(); @wYQLZ  
} PEX26==  
catch(Exception e){e.printStackTrace ();} }{#;;5KrB  
ONr?.MJ6j  
E,*JPK-A x  
} *c~'0|r  
KD,^*FkkL  
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public static void main(String[] args) G
_2gKkIK-  
{ DGa#d_I  
new TestMethod(); ~J:$gu~`  
} g)Vq5en*  
} ]b0zkoD9<  
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