http断点续传简单实现（java)

/* |Mlh;  
**SiteFileFetch.java Ox
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*/ *H*\gaSh  
package NetFox; F(0Z ]#+  
import java.io.*; u_Zm1*'?B  
import java.net.*; g< )72-h  
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public class SiteFileFetch extends Thread { ^2JPyyZa  
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:B^mV{~  
SiteInfoBean siteInfoBean = null; //文件信息Bean `vX4!@Tw  
long[] nStartPos; //开始位置 {9;eH'e  
long[] nEndPos; //结束位置 >]?Jrs  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 U#"WrWj  
long nFileLength; //文件长度 :p$EiR  
boolean bFirst = true; //是否第一次取文件 D"`[6EN[  
boolean bStop = false; //停止标志 N
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File tmpFile; //文件下载的临时信息 *
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DataOutputStream output; //输出到文件的输出流 -fQX4'3R  
*I/A,#4r  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） gPp(e j7  
public SiteFileFetch(SiteInfoBean bean) throws IOException /.)2d8,  
{ N1s.3`  
siteInfoBean = bean; u#!GMZJN  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); H9:%6sds  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 8>dq=0:  
if(tmpFile.exists ()) `$f2eB&   
{ ##2`5i-x  
bFirst = false; "B?R| Xg  
read_nPos(); ~zj"OG"zOw  
} S|) J{~QH  
else jQs*(=ls  
{ 1W0.Ufl)  
nStartPos = new long[bean.getNSplitter()]; sSy$(%  
nEndPos = new long[bean.getNSplitter()]; >\&=
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} NkoofhZ  
Z !Z,M' "  
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} lT3|D?sF  
*LEu=3lp%>  
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public void run() *bU% @O
 
{ p4y6R4kyT  
//获得文件长度 ]p\u$VY9  
//分割文件 -B,cB  
//实例FileSplitterFetch ZGzc"r(r:#  
//启动FileSplitterFetch线程 Vp\80D&
  
//等待子线程返回 oL)lyUVT  
try{ =kF?_KN  
if(bFirst) 1oB$u!6P  
{ LVoyA/F  
nFileLength = getFileSize(); $)l2G;&  
if(nFileLength == -1) >mew"0Q  
{ KZZOi:  
System.err.println("File Length is not known!"); L1rAT  
} Pwg/Vhfh  
else if(nFileLength == -2) :+<t2^)rD  
{ "B~WcC  
System.err.println("File is not access!"); _Ws#UL+Nq  
} 4*H(sq  
else zF=#6  
{ +*: }p  
for(int i=0;i<nStartPos.length;i++) L2<+#O#  
{ Mc!2mE%47m  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ),MU+*`  
} QYH."7X >  
for(int i=0;i<nEndPos.length-1;i++) tz"5+uuu  
{ ~ t"n%SgY  
nEndPos = nStartPos[i+1]; )G^p1o;\  
} ,T/GW,?  
nEndPos[nEndPos.length-1] = nFileLength; &+,:u*%  
} ~K_]N/ >  
} ,cPkx~w0  
[
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//启动子线程 tI"wVr  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; h)7v1,;w'  
for(int i=0;i<nStartPos.length;i++) $1b]xQ  
{ kHGeCJe\{  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ZMP?'0h=  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 3Hy%SN(  
nStartPos,nEndPos,i); L,E-z_<p  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 5d>nIKW  
fileSplitterFetch.start(); Z(l9>A7!  
} W;q#ZD(;  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), )nJzSN=>$  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 1bT'u5&  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ]"C| qR*  
nEndPos = " + nFileLength); D xe-XKNc.  
// fileSplitterFetch[nPos.length-1].start(); -|6V}wHg~  
KBd7|,j  
!NILpimi  
//等待子线程结束 .mC~Ry+t  
//int count = 0; '_k>*trV  
//是否结束while循环 ful]OLV+  
boolean breakWhile = false; >-UD]?>  
BvSdp6z9Iv  
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while(!bStop) ~K4k'   
{ $,}Qf0(S  
write_nPos(); 7zOhyl?  
Utility.sleep(500); h_AJI\{"  
breakWhile = true; #8S [z5 `  
2;dM:FHLhO  
7qW.h>%WE  
for(int i=0;i<nStartPos.length;i++) ~o}moE/ ;O  
{ 0@o;|N"i  
if(!fileSplitterFetch.bDownOver) ])+Sc"g4k  
{ MP6 \r  
breakWhile = false; @=02  
break; x&QNP  
} /;zZnF\e  
} un.G6|S  
if(breakWhile) xWd9%,mDNR  
break; }*xC:A%aS  
N5[_a/  
~l;yr @  
//count++; (PRaiE  
//if(count>4) s4!|v`+$M  
// siteStop(); H?rSP0.  
} cZPbD;e:  
1-4   
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System.err.println("文件下载结束！"); ]R97n|s_  
} =~,$V<+c  
catch(Exception e){e.printStackTrace ();} \/? ! 6~  
} sZ0g99eX  
_JfJ%YXy  
l*~"5f03  
//获得文件长度
=4YbVA+(  
public long getFileSize() j:3A;r\  
{ _Cu[s?,kS  
int nFileLength = -1; OI)&vQ5k  
try{ <1ztj
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URL url = new URL(siteInfoBean.getSSiteURL()); pP?<[ql[w  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); *5ka.=Qs  
httpConnection.setRequestProperty("User-Agent","NetFox"); @C!JtgO%  
}`+O$0A  
dL1~]Z y  
int responseCode=httpConnection.getResponseCode(); _Ym&UY.u#  
if(responseCode>=400) >VpP/Qf  
{ ^G]KE8  
processErrorCode(responseCode); M>`?m L  
return -2; //-2 represent access is error DR.3 J`?K  
} nEjo,   
aL_;`@4  
?AqrlR]5  
String sHeader; BZ]&uD|f  
@t{{Q1  
6Y0/i,d*  
for(int i=1;;i++) ?7r
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{ {jj]K
.&  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ;`X`c  
//Utility.log(in.readLine()); J>,'P^  
sHeader=httpConnection.getHeaderFieldKey(i); |U;w!0  
if(sHeader!=null) gJWlWVeq$  
{ Mqrt-VPh  
if(sHeader.equals("Content-Length")) ` 4s#5g  
{ >=Rd3dgDG  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); bAA'=z<  
break; d +*T@k]>M  
} mI{CM: :  
} \t&n jMWpZ  
else r9p?@P\:[  
break; -o!saX<  
} 2c*VHIl;  
} ~m,mvRS  
catch(IOException e){e.printStackTrace ();} \?5[RR  
catch(Exception e){e.printStackTrace ();} JCCx 5  
ND)M3qp2(  
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Utility.log(nFileLength); i]hR7g<  
>X@.f1/5X  
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return nFileLength; fzPgX  
} *YiD B?Si  
H4K(SGx  
S[\cT:{OE  
//保存下载信息（文件指针位置） 8ESkG  
private void write_nPos() m%BMd  
{ jS5t?0  
try{ #=)?s 8T
 
output = new DataOutputStream(new FileOutputStream(tmpFile)); UC?2mdLt^  
output.writeInt(nStartPos.length); @n~ND).  
for(int i=0;i<nStartPos.length;i++) RN cI]oJ  
{ <E(-QJ  
// output.writeLong(nPos); o$qFa9|Ec?  
output.writeLong(fileSplitterFetch.nStartPos); Yp?a=R  
output.writeLong(fileSplitterFetch.nEndPos); L@^!(  
} ]9~#;M%1  
output.close(); <+mO$0h"r  
} l1`c?Y  
catch(IOException e){e.printStackTrace ();} MRxo|A{  
catch(Exception e){e.printStackTrace ();}  t`&s  
} 5BGv^Qb_2  
BhhK|U/  
7\Yq]:;O  
//读取保存的下载信息（文件指针位置） SbQ{ >  
private void read_nPos() n=#[Mi $Y  
{ fR{WS:Pv  
try{ QKL]O*  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); @Z1?t%1  
int nCount = input.readInt(); 37<GG)  
nStartPos = new long[nCount]; l*V72!Mv  
nEndPos = new long[nCount]; +MZ2e^\F  
for(int i=0;i<nStartPos.length;i++) @)M.u3{\  
{ F0o18k_"  
nStartPos = input.readLong(); .jG.90  
nEndPos = input.readLong(); 07HX5 Hd  
}  :L+zUlsf  
input.close(); :;gwdZ  
} )I0g&e^Tzy  
catch(IOException e){e.printStackTrace ();} B+e~k?O]1  
catch(Exception e){e.printStackTrace ();} *TMM:w|1  
} ='l6&3X  
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private void processErrorCode(int nErrorCode) r%?}5"*  
{ BM}a?nnoc  
System.err.println("Error Code : " + nErrorCode); A5J#x6@  
} L:];[xa%  
,hcBiL/  
Y_ u7 0@`  
//停止文件下载 D/!G
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public void siteStop() ohG43&g~  
{ c9TkIe  
bStop = true; bgx5{!A  
for(int i=0;i<nStartPos.length;i++) _M[[o5{  
fileSplitterFetch.splitterStop(); >?Y3WPB<F  
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u  
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} WW Kr & )  
} "Mu$3w  
//负责部分文件的抓取 .cnw?EI  
**FileSplitterFetch.java E"vi+'(v  
*/ 8CHf.SXh  
package NetFox; 'J<zVD}0  
|@uhq>&  
Hwi7oXP  
import java.io.*; :Y&W)V-  
import java.net.*; ?F:C!_  
O"w_sw  
n$VPh/  
public class FileSplitterFetch extends Thread { enO=-#  
Vf* B1Zb  
]4pC\0c  
String sURL; //File URL Y K62#;  
long nStartPos; //File Snippet Start Position kKTED1MW&W  
long nEndPos; //File Snippet End Position ;?[+vf")  
int nThreadID; //Thread's ID G;.u>92r|  
boolean bDownOver = false; //Downing is over ZJ'H y5?  
boolean bStop = false; //Stop identical \~m%4kzG8J  
FileAccessI fileAccessI = null; //File Access interface LHGK!zI  
XwqfWd
_  
7qdl,z  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException "gVH;<&]  
{ QrRCsy70  
this.sURL = sURL; (inwKRH  
this.nStartPos = nStart; v6(l#,  
this.nEndPos = nEnd; gl4 f9Ff  
nThreadID = id; )e$-B]>7z  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ~<Qxw>S#  
} EwJn1Mvq  
; yC`5  
aIyY%QT  
public void run() MhXm-<4  
{ c;fyUi  
while(nStartPos < nEndPos && !bStop) (3HgI  
{ K0bmU(Xxp  
~V)VGGOL$v  
&S`'o%B  
try{ :1Yd;%>92  
URL url = new URL(sURL); jfhDi6N  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); jF2GHyB  
httpConnection.setRequestProperty("User-Agent","NetFox"); #pxet  
String sProperty = "bytes="+nStartPos+"-"; #hiDZ>nr  
httpConnection.setRequestProperty("RANGE",sProperty); xH.q  
Utility.log(sProperty); krT!AfeV  
dtXJ<1:  
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InputStream input = httpConnection.getInputStream(); )HiTYV)]'  
//logResponseHead(httpConnection); v8M#
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[UrS%]OSR  
\d8=*Zpz7  
byte[] b = new byte[1024]; oEf^o*5(  
int nRead; $XzlW=3y  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Qpu2RfP  
{ {@`Uf;hPAX  
nStartPos += fileAccessI.write(b,0,nRead); =*G'.D /*  
//if(nThreadID == 1) <{~UKi  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); WUQh[A41  
} Fd=`9N9  
@g` ,'r  
tWy<9TF  
Utility.log("Thread " + nThreadID + " is over!"); 'cCj@bZ9X  
bDownOver = true; [WSIC *|;  
//nPos = fileAccessI.write (b,0,nRead); X"r$,~  
} ?d'9TOlD  
catch(Exception e){e.printStackTrace ();} x"=q+sA  
} ~ZIRCTQ"  
} P_Ja?)GT  
Tm,L?Jh  
xVo)!83+Q  
//打印回应的头信息 [Cr~gd+q  
public void logResponseHead(HttpURLConnection con) 8-#2?=  
{ sX?7`n1U  
for(int i=1;;i++) UjK&`a;V  
{ ^d=@RTyo/  
String header=con.getHeaderFieldKey(i); Jm^jz  
if(header!=null) nf^k3QS\  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); t|,Ex7  
Utility.log(header+" : "+con.getHeaderField(header)); e;Z`&  
else +opN\`  
break; 9`VF [* 9  
} =1?yS3  
} X+BSneu  
`)P_X4e]`  
TniKH(w/  
public void splitterStop() `cRB!w=KHV  
{ T`G"2|ISS  
bStop = true; L-TVe  
} 'Z9F0l"Nr  
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+`[Sv%v&L  
} P.P>@@+d  
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/* XOFaS '.  
**FileAccess.java H2KY$;X[  
*//文件访问(定位，写) )o,0aGo>Of  
package NetFox; @=1``z#  
import java.io.*; }Elce}  
1#uw^{n  
w#b2iE+Bw  
public class FileAccessI implements Serializable{ BS.6d}G4  
.`RC,R`C  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 %05a>Rf&  
RandomAccessFile oSavedFile; _L.yt5_  
long nPos; v%Xe)D   
w\4m-Z{  
!X_~|5.  
public FileAccessI() throws IOException xo+z[OIlF  
{ 1MSu]) W  
this("",0); &d;$k  
} y?hW#l~#X  
{HDlv[O%  
z#/*LP#oY  
public FileAccessI(String sName,long nPos) throws IOException c^k. <EA  
{ -qF|Y f  
oSavedFile = new RandomAccessFile(sName,"rw"); u{z{3fW_  
this.nPos = nPos; 'kK%sE   
oSavedFile.seek(nPos); oPBjsQ  
} x=)$sD-3  

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_XPc0r:?>  
public synchronized int write(byte[] b,int nStart,int nLen) u&bU !ZI  
{ tsD^8~ t|h  
int n = -1; 55\
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try{ JH#?}L/0Fe  
oSavedFile.write(b,nStart,nLen); 
!}7m^  
n = nLen; lY`<-`{I_  
} S#dS5OX  
catch(IOException e) }IL@j A
 
{ Awh)@iTL  
e.printStackTrace (); mws.)  
} eW%jDsC  
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return n; eo[^ij  
} W aU_Z/{0  
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} AJu.  
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/* "N_?yA#(j  
**SiteInfoBean.java tAUMSr|?  
*/ nc)`ISI  
package NetFox; K%;yFEZ  
~O6=dR  
Is
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public class SiteInfoBean { ":ycyN@g  
79_MP  
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private String sSiteURL; //Site's URL 9m{rQ P/  
private String sFilePath; //Saved File's Path *Q?HaG|S  
private String sFileName; //Saved File's Name dGe  
private int nSplitter; //Count of Splited Downloading File CS49M  
yk/XfwQ5  
rB]/N,R  
public SiteInfoBean() u.6%n.g  
{//nSplitter的缺省值为5 FReK   
//default value of nSplitter is 5 T*
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this("","","",5); QTH yH  
} ?%(*bRV -  
Pl4d(2 7  
;nE}%lT  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ;]!  
{ _NFJm(X.  
sSiteURL= sURL; FBsw\P5w  
sFilePath = sPath; [@;Z xs  
sFileName = sName; :|Cf$2k7  
this.nSplitter = nSpiltter; 9tO_hhEQ@  
Ai;Pht9qi  
_1ins;c52  
} Qsa2iw{  
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yr?\YKV)I  
public String getSSiteURL() 566EMy|  
{ Wj&s5;2a  
return sSiteURL; &n|gPp77$  
} *
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i{2KMa{K  
public void setSSiteURL(String value) P;34Rd  
{ YQ/*|  
sSiteURL = value; z5I<,[`  
} _PF><ODX2  
$)3/N&GXR  
{+;8dtZ)x  
public String getSFilePath() ?jbam!A  
{ W2RS G~|  
return sFilePath; kVY@q&p  
} C;` fOCz^  
jolCR-FDu  
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im
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public void setSFilePath(String value) ]+AI:  
{ $1e@3mzM  
sFilePath = value; H\T h4teE  
} 15COwc*k  
?4_;9MkN  
_[x(p6Xp  
public String getSFileName() 8'y|cF%U  
{ 8Bhng;jX  
return sFileName; u8*0r{kOH  
} mN{$z<r  
dn Xc- <  
)lbF'.i  
public void setSFileName(String value) pmC@ fB  
{ vd~O:=)4  
sFileName = value; x{m)I<.:  
} =GF+hM/~  
deNU[  
4{|lzo'&  
public int getNSplitter()
J [1GP_  
{ x;+,lP  
return nSplitter; (H$eXW7  
} \ys3&<;b  
2.6,c$2tB  
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public void setNSplitter(int nCount) #xmUND`@  
{ -Jhf]  
nSplitter = nCount; }~7>S5  
} IAfYlS#<yD  
} @:Ns`+ W*  
&HWH UWB  
/<mc~S7  
/* \sk,3b
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**Utility.java 1xw},y6T2  
*/ Z1Ms~tch  
package NetFox; :!%oQQO  
X**w
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public class Utility { 6c2fqAF>i  
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\1tce`+  
public Utility()
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{ |aZ^K\yIF  
{Z|C  
?}W:DGudZ  
} ?B-aj  
,yB-jk?  
//线程睡眠 D!:Qy@Zw  
public static void sleep(int nSecond) bc+'n  
{ hJ|z8Sy@1  
try{ TqWvHZX  
Thread.sleep(nSecond); ag3T[}L z  
} B$\5=[U  
catch(Exception e) 9U+^8,5  
{ 2-$R@ SVy  
e.printStackTrace (); 9qw~]W~Nm  
} ^!A{ 4NV  
} }Iu6]?|'  
Va1|XQ<CL  
//日志 "MyYu}AD  
public static void log(String sMsg) 7
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{ hVd63_OO  
System.err.println(sMsg); QPBf++|  
} +'[iyHBJ  
3mx7[Q  
~WVrtYJu  
public static void log(int sMsg) m^TkFt<BM  
{ ;$W|FpR2  
System.err.println(sMsg); +ux,cx.U"  
} (j2]:BVu  
} [x@iqFO9  
9{+B lNZ  
&)rm
v  
/* 3iY`kf  
**TestMethod.java Z!*Wn`d-k  
*/ /ZAEvdO*P  
package NetFox; " I:j a7  
'06[@Cw  
,\Cy'TSz  
public class TestMethod { 6n>+cX>E  
&e
d.%:  
P*\.dAi  
public TestMethod() }APf^Ry  
{ ///xx/weblogic60b2_win.exe f9;M"Pd  
try{ $[IuEdc/  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); _v_ak4m>  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); T;I a;<mfE  
SiteFileFetch fileFetch = new SiteFileFetch(bean); CnJO]0Op3  
fileFetch.start(); q'PA2a:  
} m,-:(82  
catch(Exception e){e.printStackTrace ();} J.~$^
-&!  
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} KpSHf9!&[  
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[7$.)}Q-  
public static void main(String[] args) '#^ONnSTn  
{ =T9QmEBm  
new TestMethod(); qRTy}FU1  
} T'FRnC^~  
} iQ:]1H s  
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