http断点续传简单实现（java)

/* \s!x;nw[  
**SiteFileFetch.java 9TwKd0AT$&  
*/ qd<I;*WV  
package NetFox; *]nk{jo2  
import java.io.*; `>OKV;~{z  
import java.net.*; A2$05a$%  
<j3|Mh_(I  
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public class SiteFileFetch extends Thread { }7_$[r'_oI  
E()%IC/R  
0 ZSn r+  
SiteInfoBean siteInfoBean = null; //文件信息Bean rinTB|
5  
long[] nStartPos; //开始位置 WQbjq}RfI  
long[] nEndPos; //结束位置 d]MpE9@'v  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 OL_jU2,fv  
long nFileLength; //文件长度 X,{[R |  
boolean bFirst = true; //是否第一次取文件 Av4(=}M}@  
boolean bStop = false; //停止标志 ) $0>L5d:  
File tmpFile; //文件下载的临时信息 RE4WD9n  
DataOutputStream output; //输出到文件的输出流 qh6rMqq  
}0iHf'~DH*  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） Xz9[0;Q  
public SiteFileFetch(SiteInfoBean bean) throws IOException qW'L}x  
{ J~50#vHY  
siteInfoBean = bean; y|zIuI-p  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); >]o>iOz;]  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); v["_t/_  
if(tmpFile.exists ()) !~V^GlY  
{ \ FJ ae  
bFirst = false; c _!!DEe7  
read_nPos(); 6Nt/>[  
} 7p1B"%  
else z7+>G/o  
{ 0Ue~dVrM(?  
nStartPos = new long[bean.getNSplitter()]; N Hn#c3o  
nEndPos = new long[bean.getNSplitter()]; \jmZt*c  
} eN\+  
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;cZp$ xb3  
} L27WDm^)  
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public void run() USS%T<Vk  
{ X*:,|  
//获得文件长度 E0yx @Vx  
//分割文件 [rL 8L6,!  
//实例FileSplitterFetch %wI)uJ2  
//启动FileSplitterFetch线程 ;8^(Z  
//等待子线程返回 u?H.Z  
try{ U3`?Z`i(  
if(bFirst) g/i%XTX>  
{ 1 -C~C]&  
nFileLength = getFileSize(); Ob}XeN(L3  
if(nFileLength == -1) L u'<4 R  
{ B*w]yL(  
System.err.println("File Length is not known!"); p1K]m>Y{?  
} ei{tW3 H$  
else if(nFileLength == -2) 5&O%0`t  
{ Y=g]\%-PB  
System.err.println("File is not access!"); /7fd"U$Lh  
} '@Yp@ _  
else zqBzataR:  
{ \ 9iiS(e  
for(int i=0;i<nStartPos.length;i++) 7(a1@VH  
{ WW>m`RU`  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Tj{3#?]Ho  
} .wyuB;:  
for(int i=0;i<nEndPos.length-1;i++) t\TxK7i  
{ El: @l%  
nEndPos = nStartPos[i+1]; &Yc'X+'4  
} es~1@Jb  
nEndPos[nEndPos.length-1] = nFileLength; 3^xq+{\)  
} y)a)VvU":  
} &U7h9o H  
MvnQUZ  
= ^Vp \  
//启动子线程 rHk,OC  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; WiZTE(NM`  
for(int i=0;i<nStartPos.length;i++) .l5-i@=W  
{ . UH'U\M  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Nu\<Xr8  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), IV1Y+Z )  
nStartPos,nEndPos,i); Dln1 R[  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 9%"`9j~H>  
fileSplitterFetch.start(); 1uCF9P ai  
} >tx[UF@P@  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), SM2
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); r4DHALu#)  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", qvK/}  
nEndPos = " + nFileLength); <;O^3_'  
// fileSplitterFetch[nPos.length-1].start(); DdUw~n,  
*Ms"{+C  
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//等待子线程结束 6x=w-32+ y  
//int count = 0; zSU,le  
//是否结束while循环 oif|X7H;  
boolean breakWhile = false; 6-0sBB9=u  
I,`;#Q)nx  
HtiIg a 7  
while(!bStop) KfYU.Q  
{ 4d}=g]P  
write_nPos(); \7>*ULP  
Utility.sleep(500); ?6{g7S%  
breakWhile = true; t|hc`|  
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for(int i=0;i<nStartPos.length;i++) X!mJUDzh]  
{ u[Si=)`VPk  
if(!fileSplitterFetch.bDownOver) `JpFqZ'58  
{ ~zG)<S"q  
breakWhile = false; hayJgkZ'  
break; p<#aXsjy  
} LExm#T`  
} k?TZY|_  
if(breakWhile) \AH5zdK  
break; oP%5ymL%J  
0"T/a1S7bl  
&vt)7[  
//count++; o3GkTn O  
//if(count>4) H{,1-&>|  
// siteStop(); )S 4RR2Q>  
} :z&kbG  
}+G5i_a  
~{yy{  
System.err.println("文件下载结束！"); 80'@+AD  
} +,AzxP _y  
catch(Exception e){e.printStackTrace ();} xkiiQs)  
} D7JrGaF{  
$u'"C|>8  
) \TH'  
//获得文件长度 oz)4YBf  
public long getFileSize() sgGA0af  
{ a0gg<Ml  
int nFileLength = -1; V,0$mBYa  
try{ Wf"GA i  
URL url = new URL(siteInfoBean.getSSiteURL()); &rD8ng+$  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); D4|Ajeo;1  
httpConnection.setRequestProperty("User-Agent","NetFox"); /4 OmnE;  
r@q
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k ,+,,W  
int responseCode=httpConnection.getResponseCode(); PnInsf%;  
if(responseCode>=400) q5=,\S3=  
{ =~Qg(=U0U  
processErrorCode(responseCode); kp*!  
return -2; //-2 represent access is error JGTsVa2  
} m"'LT0nur  
US(RWXyg  
*<y9.\zY<  
String sHeader; SZ9DT  
3Il._]#  
E;x-O)(&  
for(int i=1;;i++) vYb4&VV  
{ W02z}"#  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); v<g=uEpN  
//Utility.log(in.readLine()); #$-?[c$>  
sHeader=httpConnection.getHeaderFieldKey(i); oYTLC@98}  
if(sHeader!=null) v;9(FLtL  
{ B5vLV@>]  
if(sHeader.equals("Content-Length")) U5H%wA['m  
{ TK[[6IB  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); njg0MZBqA  
break; zGyRzxFN  
} UH}lKc=t  
} ~jzLw@"~$^  
else W&R67ff|  
break; @48!e-W  
} R6oD  
} o5DT1>h  
catch(IOException e){e.printStackTrace ();} jOrfI-&.G  
catch(Exception e){e.printStackTrace ();} 1/w8'Kf'u  
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Utility.log(nFileLength); F0z7".)  
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return nFileLength; 8a)Brl}u  
} rf4f'cUa  
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)  
cnQ2/ZZp~  
//保存下载信息（文件指针位置） ;*j 
K!  
private void write_nPos() Z'y&11  
{ KB|mtsi  
try{ %A'mXa
tk  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Xm>zT'B_tJ  
output.writeInt(nStartPos.length); ;hO6 p  
for(int i=0;i<nStartPos.length;i++) _.V5-iN  
{ "``>ii  
// output.writeLong(nPos); ;<Hk Cd  
output.writeLong(fileSplitterFetch.nStartPos); ."^\1N(.n  
output.writeLong(fileSplitterFetch.nEndPos); 6)*fr'P  
} .!0Rh9yyl  
output.close(); k)*apc\W  
} =Q<7
[  
catch(IOException e){e.printStackTrace ();} kBcTXl  
catch(Exception e){e.printStackTrace ();} ]bh%pn  
} JG'%HJ"D  
i]? Eq?k  
d]O:VghY\  
//读取保存的下载信息（文件指针位置） v+in:\Dv  
private void read_nPos() WA43}CyAe  
{ 7:pc%Ksq  
try{ (1^;l;7H  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); F%o!+%&7  
int nCount = input.readInt(); 4jTO:aPh_  
nStartPos = new long[nCount]; R@jMFh;  
nEndPos = new long[nCount]; L{&2 P  
for(int i=0;i<nStartPos.length;i++) Q~Mkf&s  
{ [O&}Qk  
nStartPos = input.readLong(); S@u46X>  
nEndPos = input.readLong(); 0m*b9+q  
} )AkBo  
input.close(); &T0]tzk*,  
} -i{_$G8W/c  
catch(IOException e){e.printStackTrace ();} #UL75  
catch(Exception e){e.printStackTrace ();} X5/fy"g&  
} 6[ 3 K@  
k &J;,)V  
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private void processErrorCode(int nErrorCode) s.Z{mnD6  
{ xCXsyZ2h  
System.err.println("Error Code : " + nErrorCode); cYgJ}(>}  
} nng|m  
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b:hta\%/2  
//停止文件下载 (:OMt2{r  
public void siteStop() _xePh   
{ aHuMm&  
bStop = true; Qw2-Vv4!"  
for(int i=0;i<nStartPos.length;i++) jGz~}&B  
fileSplitterFetch.splitterStop(); l9Ol|Cb&  
wods   
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} u_' -vZ_  
} DoQ^caa@  
//负责部分文件的抓取 ;6pB7N  
**FileSplitterFetch.java m=@xZw<  
*/ "Ux(n
t  
package NetFox; +vxf_*0;  
\)t//0  
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import java.io.*; E!1\9wzM{  
import java.net.*; }M%3  
0>SA90Q  
\&kj#)JYA  
public class FileSplitterFetch extends Thread { M KW~rrR  
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String sURL; //File URL ]R)wBug
 
long nStartPos; //File Snippet Start Position ZwsQ}5
 
long nEndPos; //File Snippet End Position `9[n5-t  
int nThreadID; //Thread's ID B3&C&o.h  
boolean bDownOver = false; //Downing is over 8j70X <R  
boolean bStop = false; //Stop identical o"BED!/  
FileAccessI fileAccessI = null; //File Access interface NO[A00m|OL  
+&VY6(Zj+*  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException H%Vf$1/TF  
{ vA_,TS#Bo  
this.sURL = sURL; mm+V*L{x  
this.nStartPos = nStart; 5)XUT`;'){  
this.nEndPos = nEnd; ,P}7e)3  
nThreadID = id; &t<gK D  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ^uUA41o`eJ  
} }W:Z>vam+  
8,IF%Z+LI  
5|~g2Zz{;  
public void run() qqZ4K:oC,  
{ tT)s,R%  
while(nStartPos < nEndPos && !bStop) >Z_;ZMu)  
{ kEC^_sO"  
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try{ +u$JMp  
URL url = new URL(sURL); %8u9:Cl):  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); #2U#h-vI  
httpConnection.setRequestProperty("User-Agent","NetFox"); E~WbV+,3  
String sProperty = "bytes="+nStartPos+"-"; SF;\*]["f  
httpConnection.setRequestProperty("RANGE",sProperty); 0;><
@{'  
Utility.log(sProperty); Za!KM  
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+ho=0>  
InputStream input = httpConnection.getInputStream(); MnFrQC  
//logResponseHead(httpConnection); 0M;El2 P$  
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byte[] b = new byte[1024]; 5`fUR/|[  
int nRead; zo@vuB.  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 9FSa=<0wE  
{ mB>0$l y  
nStartPos += fileAccessI.write(b,0,nRead); 9HFEp-"  
//if(nThreadID == 1) PZ6R+n8  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Q`8-|(ngw  
} 98u@X:3  
$Xt""mlQ  
6T4DuF  
Utility.log("Thread " + nThreadID + " is over!"); Ey:?!  
bDownOver = true; "Y:>^F;  
//nPos = fileAccessI.write (b,0,nRead); 8*/;W&7y  
} azIhp{rHw  
catch(Exception e){e.printStackTrace ();} 0'F/z%SMj  
} C)i8XX  
} LWqKSNE;  
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//打印回应的头信息 SPlt=*C#_  
public void logResponseHead(HttpURLConnection con) dF51_Kk  
{ ~;$QSO\2h  
for(int i=1;;i++) L3oL>r'|  
{ .yfp-n4H  
String header=con.getHeaderFieldKey(i); $s}w23nB  
if(header!=null) :F"IOPfU5[  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); <& PU%^Ha  
Utility.log(header+" : "+con.getHeaderField(header)); sS{Co8EJn  
else ^wZx=kas  
break; TC<Rg?&yb  
} 6c^?DLy9B  
} t|oIzjKE/  
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public void splitterStop() i?pd|J  
{ Dom]w.W5  
bStop = true; 8%;Wyqdf]  
} 30WOH 'n  
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0U%tjYk(  
} &8i$`6wY  
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/* y7h^_D+Ce  
**FileAccess.java _/Ve~( "  
*//文件访问(定位，写) BJ3<"D{.*4  
package NetFox; |$IL:W6  
import java.io.*; f@!9~s  
$}b)EMMM  
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public class FileAccessI implements Serializable{ Kh=\YN\E<  
{06-h %qr  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 L /
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RandomAccessFile oSavedFile; P-T@'}lW  
long nPos; +`"Tn`O  
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public FileAccessI() throws IOException ML|?H1m>  
{ UZFs]z!,k  
this("",0); AEj%8jh  
} RrBG=V  
5!'1;GLs  
:D3:`P>,c  
public FileAccessI(String sName,long nPos) throws IOException  1h
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{ 93.\.&L\  
oSavedFile = new RandomAccessFile(sName,"rw"); MkGQ  
this.nPos = nPos; '")'h  
oSavedFile.seek(nPos); `"ks0@^U  
} %k?/pRv$>  
AfO.D?4x  
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public synchronized int write(byte[] b,int nStart,int nLen) NL|c5y<r  
{ 7P2(q  
int n = -1; a,4GE'  
try{ 6`'g ${U  
oSavedFile.write(b,nStart,nLen); )d3C1Pd>  
n = nLen; sbVEA  
} I&i6-xp  
catch(IOException e) PtQ[({d3R  
{ .,'4&}N}  
e.printStackTrace (); _VgFuU$h  
} o@PvA1  
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return n; oVP,ar0G  
} T[e+iv<8j
 
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} &?p(UY7'"  
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:/SGB3gb1t  
/* xv147"w'v  
**SiteInfoBean.java I8@leT\9M  
*/ '-f` 5X  
package NetFox; _&gO>G,uy  
wpN [0^M-0  
&.2
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public class SiteInfoBean { 5G'2 Wby'#  
a(fiW%eFb  
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private String sSiteURL; //Site's URL Q: -&
  
private String sFilePath; //Saved File's Path 46 0/eW\  
private String sFileName; //Saved File's Name gGCr~.5  
private int nSplitter; //Count of Splited Downloading File P5G0fq7  
Rq2bj_j  
h*<`ct xL  
public SiteInfoBean() .#tA .%  
{//nSplitter的缺省值为5 `%Kj+^|DS  
//default value of nSplitter is 5 5G2ueRVb  
this("","","",5); < <0[PJ  
} >\'}&oi  
YwH Fn+  
$!p2Kf>/Q  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) @Kt!uKrI  
{ tr0kTW$Ad  
sSiteURL= sURL; %kkDitmI{  
sFilePath = sPath; r&v!2A]:  
sFileName = sName; <x<qO=lq  
this.nSplitter = nSpiltter; J<"Z6 '0v  
&a\w+  
&'/PEOu&}G  
} 3zfiegY@wm  
~3Qa-s;g  
leSBR,C  
public String getSSiteURL() /'VuMMJ2  
{ 1bw$$QXC_  
return sSiteURL; ODpAMt"  
} {='wGx  
n]w%bKc-9  
{EoZ}I  
public void setSSiteURL(String value) )9/i
H(  
{ %(%EEt  
sSiteURL = value; AYoTCi%7E  
} "\~>[on  
M`=\ijUwN  
oWDn_GnG`h  
public String getSFilePath() `T%nGVl>\  
{ =
*-ac  
return sFilePath; GM^H )8U  
} r da: ~  
.;bU["fn)  
,Bx0  
public void setSFilePath(String value) pXQ$n:e  
{ (yEU9R$I"  
sFilePath = value; 71<4q{n  
} tmoclK-  
-c0*  
xjxX4_  
public String getSFileName() Om7 '_}  
{ MdkL_YP}.  
return sFileName; \q!TI x  
} 06pY10<>X  
nC$c.K'  
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public void setSFileName(String value) -~~R?,H'Z_  
{ vgNrHq&2q  
sFileName = value; h^WMv *2  
} C^]UK  
PK{FQ3b2{  
)P+<=8@a  
public int getNSplitter() #MMp0  
{ R5},E  
return nSplitter; O#8lJ%?  
} X,8Zn06
M  
WwKpZ67$R  
b9b`%9/L  
public void setNSplitter(int nCount) HyQ(9cn|  
{ Mg^A,8lrm  
nSplitter = nCount; 7Y4D9pw  
} Csgby(D*O  
} =@P(cFJ/  
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Vd) %qw  
/* cqb6]  
**Utility.java hJ4 A5m.  
*/ axXR
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package NetFox; ;'!h(H  
I[06R
 
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public class Utility { ^}z:FI   
/Vv)00  
~(rZ)  
public Utility() sG|,#XQ  
{ gV5mERKs  
rb>2l3g*  
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} p .~5k  
`Y '-2Fv  
//线程睡眠 %3K'[2F  
public static void sleep(int nSecond) 4;IZ}9|G  
{ >;xkiO>Y  
try{ !0X"^VB  
Thread.sleep(nSecond); I|/|\  
} eNFA.*p<  
catch(Exception e) 85FzIX-F%  
{ ^(qR({cX  
e.printStackTrace (); nu16L$]  
} P^BSl7cT  
} 3[kl` *`  
z5f3T D6,  
//日志 ; ?,'jI*1  
public static void log(String sMsg) rO,n~|YJ  
{ 7B)@ aUj$  
System.err.println(sMsg); d5W=?  
} b%j4W)Z  
uy=<n5`oNG  
#D+.z)iZn  
public static void log(int sMsg) ?/Aql_?3  
{ DxP65wU  
System.err.println(sMsg); $*9:a3>zny  
} /hGu42YG  
} 1Zp^X:(  
cgQ2Wo7tCq  
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/* mO0#xY_z  
**TestMethod.java *^\u%Ir"  
*/ Vgj[m4l  
package NetFox; 1
!ijRr  
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c 8|&Q  
public class TestMethod { 0gKSjTq
o  
~Z9
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R"71)ob4  
public TestMethod() vrsOA@ee3H  
{ ///xx/weblogic60b2_win.exe OF(tCK  
try{ KZ/2W9r_,  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Y;sN UX  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ,fs>+]UY3  
SiteFileFetch fileFetch = new SiteFileFetch(bean); \mwxV!!b$  
fileFetch.start();  !h*F58  
} wA%,_s/U  
catch(Exception e){e.printStackTrace ();} dM5N1$1,  
pA5X<)~   
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} 8{-bG8L> 5  
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3.04Toq!  
public static void main(String[] args) [sG!|@r  
{ HD}3mP  
new TestMethod(); *C^`+*}OE$  
} k/%n7 ;1  
} f87lm*wZ  
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