http断点续传简单实现（java)

/* s|:
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**SiteFileFetch.java _znn`_N:v  
*/ AC?a:{./  
package NetFox; Y5mk*Q#q  
import java.io.*; 97}l`z;Z  
import java.net.*; !}"PHby5N  
]99;7  
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public class SiteFileFetch extends Thread { 5N2`e3:I  
*E/CNMn=E  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ~yRKNH*M  
long[] nStartPos; //开始位置 J p0j  
long[] nEndPos; //结束位置 o4B%TW  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 U\"FYTC  
long nFileLength; //文件长度 S\2@~*{-
8  
boolean bFirst = true; //是否第一次取文件 j>hBNz  
boolean bStop = false; //停止标志 *OY Nx4k  
File tmpFile; //文件下载的临时信息 xl(R|D))  
DataOutputStream output; //输出到文件的输出流 u&o<>d
;)  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） [XNDYaF8
 
public SiteFileFetch(SiteInfoBean bean) throws IOException AIM
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{ 0T:U(5Y9  
siteInfoBean = bean; A] f^9F@  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ev5m(wR  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); $ 3.Y2&$T  
if(tmpFile.exists ()) s`dUie}y<  
{ R, UYwI  
bFirst = false; @u-CR8^  
read_nPos(); !z+'mF?V+X  
} 42PA?^xPw  
else CYhSCT!-?  
{  KzZRFEA_  
nStartPos = new long[bean.getNSplitter()]; D[K!xq  
nEndPos = new long[bean.getNSplitter()]; rJCu6  
} L\t?^u  
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)!=X?fz,O  
4 :M}Vz-  
} Ce@"+k+w  
)p 8P\Rl  
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public void run() BvpUcICJ  
{ >q1rdq  
//获得文件长度 %VO>6iVn  
//分割文件 #>">fs]  
//实例FileSplitterFetch ,y[w`Q\  
//启动FileSplitterFetch线程 k6|/ik9C  
//等待子线程返回 Vx=tP.BO]  
try{ 6oq/\D$6~  
if(bFirst) A7GWU{i  
{ Ak@y"!wnM  
nFileLength = getFileSize(); $gaGaB  
if(nFileLength == -1) 7_
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{ HurF4IsHk  
System.err.println("File Length is not known!"); Zy^ wS1io  
} qGECw#  
else if(nFileLength == -2) }?,Eb~q  
{ )3)f
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System.err.println("File is not access!"); 1<pb=H  
} D#d \1g  
else 7m;<b$  
{ O7zj8  
for(int i=0;i<nStartPos.length;i++) IMHt#M`  
{ LOe l6Ui  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); KzLkT7,y+  
} 0Q:l,\lY  
for(int i=0;i<nEndPos.length-1;i++) =nG>aAG  
{ \m~Oaf;$  
nEndPos = nStartPos[i+1]; ?2Sm f  
} \_t[\&.a}  
nEndPos[nEndPos.length-1] = nFileLength; .-.b:gdO(  
} /3qKsv#  
} (bGk=q=M  
3U[:N &Jb  
 J?qikE&  
//启动子线程 UkM#uKr:  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; kC/An@J^#  
for(int i=0;i<nStartPos.length;i++) T)Pr%kF  
{ 7J5Yzu)D  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), J
'
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), rVDOco+w  
nStartPos,nEndPos,i); zKNac[:  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); F|?}r3{aJ  
fileSplitterFetch.start(); UMlvu?u2p1  
} lO8GnkLE  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), jluv}*If  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); rnM C[  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 7O'u5N  
nEndPos = " + nFileLength); rh6 e  
// fileSplitterFetch[nPos.length-1].start(); Ft?Yc 5  
$~'G<YYF4  
|pR'#M4j4A  
//等待子线程结束 !+n'0{  
//int count = 0; 9oj0X>| 1  
//是否结束while循环 Bn*QT:SKC  
boolean breakWhile = false; ->J5|c#  
IgKrcpK#}?  
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while(!bStop) a#+;BH1  
{ @[j%V ynf  
write_nPos(); HK`r9frn  
Utility.sleep(500); 8n/[oDc]  
breakWhile = true; jN!sLW  

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\1#~]1~ s  
for(int i=0;i<nStartPos.length;i++) `i6q\-12n  
{ #QiNSS  
if(!fileSplitterFetch.bDownOver) Fhs/<w-  
{ "QM2YJ55m`  
breakWhile = false; S vW{1  
break; PH=O>a`a_O  
} Hh &s.ja  
} z"V`8D  
if(breakWhile) 1c:/c|shQ_  
break; JUTlJyx8  
e(jD[q  
|O[ I=!  
//count++; 9oVprd>%@  
//if(count>4) K(_8oB784  
// siteStop(); ]O&yy{yYK  
} j +Ro?  
[B%:!Q)@  
u\=yY.   
System.err.println("文件下载结束！"); ^fti<Lw5  
} c1g'l.XL 3  
catch(Exception e){e.printStackTrace ();} M>@PRb:Oc  
} U6~79Hnt  
U (A#}  
v8K4u)  
//获得文件长度 NeniQeR  
public long getFileSize() {$v>3FG  
{ Y2(,E e2  
int nFileLength = -1; x24&mWgU  
try{ *TYOsD**9  
URL url = new URL(siteInfoBean.getSSiteURL()); I
6[=tB  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); _j|U>s   
httpConnection.setRequestProperty("User-Agent","NetFox"); 8lF:70wia  
u(4o#m  
8%^W<.Y  
int responseCode=httpConnection.getResponseCode(); Lg+cHaA  
if(responseCode>=400) u$+nl~p[&  
{ R3E|seR  
processErrorCode(responseCode); +}NQ|y V  
return -2; //-2 represent access is error USbFUHdDc  
} M/jdMfU  
(2r808^2  
1f0maN  
String sHeader;
>@q4Uez  
:bz;_DZP  
)Z63 cr/  
for(int i=1;;i++) sKDL=c;?j  
{ MMf_  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); }1Pv6L(o)  
//Utility.log(in.readLine()); ,w7ZsI4:[  
sHeader=httpConnection.getHeaderFieldKey(i); _ Zzne  
if(sHeader!=null) Q=#!wWVP  
{ h($Jo  
if(sHeader.equals("Content-Length")) ` NWmwmWB"  
{ !-q)9K?  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ?^{Ey[)'(  
break; (h%xqXs  
} ou[Wz{  
} fl<j]{*v  
else 3y-P-NI~=  
break; =+VI{~.|}  
} |=EwZmj-c  
} u1/q8'RW  
catch(IOException e){e.printStackTrace ();} pcPRkYT[M  
catch(Exception e){e.printStackTrace ();} j4Y] 8  
5!7vD|6  
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Utility.log(nFileLength); ~JohcU}d  
k:CSH{s5{  
seNH/pRb  
return nFileLength; RBOhV/f  
} =B ts  
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F1&7m )f$l  
//保存下载信息（文件指针位置） T$s)aM  
private void write_nPos() n16TQe"8  
{ ;Yn_*M/*  
try{ gOm%?sg  
output = new DataOutputStream(new FileOutputStream(tmpFile)); U<U?&hB\@  
output.writeInt(nStartPos.length); a,\GOy(q{  
for(int i=0;i<nStartPos.length;i++) 7dXh,sD  
{ hVu~[ 'Me  
// output.writeLong(nPos); R!7a;J}  
output.writeLong(fileSplitterFetch.nStartPos); zl["}I(*n  
output.writeLong(fileSplitterFetch.nEndPos); ]`eJSk.  
} dhI+_z   
output.close(); x DX_s:A  
} u %&4[zb  
catch(IOException e){e.printStackTrace ();} rOXh?r  
catch(Exception e){e.printStackTrace ();} $q$\  
} 60%EmX ;  
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//读取保存的下载信息（文件指针位置） QlWkK.<Z3_  
private void read_nPos() 1Yy*G-7}  
{ 5fud:k  
try{ ]\oE}7K%r  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); T!gq Z  
int nCount = input.readInt(); }o9(Q8  
nStartPos = new long[nCount]; Y# ?M%I%j  
nEndPos = new long[nCount]; 1A/li%  
for(int i=0;i<nStartPos.length;i++) KS(Ms*k;'  
{ F` ]s  
nStartPos = input.readLong(); 0+"P1/  
nEndPos = input.readLong(); s&Qil07Vl  
} >)S'`e4Gu  
input.close(); )lB*] n`Z]  
} wvg>SfV,e  
catch(IOException e){e.printStackTrace ();} B<?fD  
catch(Exception e){e.printStackTrace ();} S[oRq   
} 407;M%?'A  
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private void processErrorCode(int nErrorCode) [[d@P%X&  
{ "Kt[jV;6  
System.err.println("Error Code : " + nErrorCode); &|) (lX  
} YM]ZL,8  
SZ"^>}zl=  
vxx7aPjC  
//停止文件下载 Y4n;[nHQ(  
public void siteStop() NI% ()  
{ oi}\;TG  
bStop = true; D1<$]r,  
for(int i=0;i<nStartPos.length;i++) b-,]21  
fileSplitterFetch.splitterStop(); k84JDPu#  
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} @Xe[5T  
} Ok2>%e  
//负责部分文件的抓取 p&ml$N9fd  
**FileSplitterFetch.java ;R.l?Bg  
*/ #3act)m  
package NetFox; JK9}Kb};  
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import java.io.*; k,nRC~Irh  
import java.net.*; ,zY!EHpx  
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public class FileSplitterFetch extends Thread { d>qxaX;  
xkzC+ _A  
y*5bF0  
String sURL; //File URL mf)o1O&B  
long nStartPos; //File Snippet Start Position U4@W{P02  
long nEndPos; //File Snippet End Position \aG:l.IM0  
int nThreadID; //Thread's ID wFJ?u?b0Q  
boolean bDownOver = false; //Downing is over `Dco!ih  
boolean bStop = false; //Stop identical /N&)r wc  
FileAccessI fileAccessI = null; //File Access interface 13nXvYo'  
Fv6<Cz6L  
D>Qc/+  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 9 6'{ES9D  
{ *0`oFTJ  
this.sURL = sURL; Z{ A)  
this.nStartPos = nStart; " '/$ZpY
 
this.nEndPos = nEnd; 0UB,EI8  
nThreadID = id; F
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fileAccessI = new FileAccessI(sName,nStartPos);//定位 d?/?VooU  
} ?Q)z5i'g#  
B^SD5  
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public void run() 6*<=(SQI  
{ Z)zWfv}  
while(nStartPos < nEndPos && !bStop) iPxhDn<B  
{ .hxcx>%  
JL4\%
 
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try{ Z;{3RWV  
URL url = new URL(sURL); N'nqVYTU  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Sh=Px9'i  
httpConnection.setRequestProperty("User-Agent","NetFox"); I%NPc4p  
String sProperty = "bytes="+nStartPos+"-"; ,HxsU,xiG  
httpConnection.setRequestProperty("RANGE",sProperty); I9`R LSn  
Utility.log(sProperty); btK| U  
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InputStream input = httpConnection.getInputStream(); o
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//logResponseHead(httpConnection); j3bTa|UdT  
?5qo>W<7  
uLsGb=m%b  
byte[] b = new byte[1024]; -T4{PM  
int nRead; AT:T%a:G?  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) p0xd c3  
{ an 3"y6.8  
nStartPos += fileAccessI.write(b,0,nRead); 7RmL#f`  
//if(nThreadID == 1) d]OoJK9&&  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); VJX{2$L  
} g< cR/  
*=1;HN3  
fn zj@_{|  
Utility.log("Thread " + nThreadID + " is over!"); .[hQ#3)W  
bDownOver = true; ~a[]4\m;  
//nPos = fileAccessI.write (b,0,nRead); 8z^?PZ/  
} _M+'30  
catch(Exception e){e.printStackTrace ();} sD$ \!7:b  
} \#[W8k<Z  
} aXyu%<@k  
q
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//打印回应的头信息 [IVT0 i  
public void logResponseHead(HttpURLConnection con) 2,O-/A;tW*  
{ )EYsqj  
for(int i=1;;i++) J'4{+Q_pa  
{ 0Ng6Xg(QHc  
String header=con.getHeaderFieldKey(i); BciwS_Qx  
if(header!=null) OE-$P  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); cve(pkl  
Utility.log(header+" : "+con.getHeaderField(header)); Jp.Sow  
else ?#xNz=V  
break; BBw`8!  
} J"8bRp=/|  
} /d5_-AB(v  
lnW/T--  
^ 3LM%B  
public void splitterStop() !arcQ:T@G  
{ $Trkow%F]  
bStop = true; p2
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} -9/YS  
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} a J[VX)"J  
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{o7ibw=E)  
/* M|FwYF^  
**FileAccess.java z.eqOPW  
*//文件访问(定位，写) f3U#|(%(*  
package NetFox; ?V#%^ 57p  
import java.io.*; jHBn^Nly  
0G9@A8LU  
]c+qD,wqt>  
public class FileAccessI implements Serializable{ +Bv{A3E9  
"j3Yu4_ks  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 skdSK7 n  
RandomAccessFile oSavedFile; $I-$X?  
long nPos; BgD;"GD*W  
@g[p>t> *  
d6
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public FileAccessI() throws IOException WDKj)f9cy  
{ N2;T\xx,  
this("",0); WE4
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} Ka2U@fK"  
OCo=h|qBp  
:q;vZ6Xd  
public FileAccessI(String sName,long nPos) throws IOException ?AyG!F  
{ 5|xFY/%  
oSavedFile = new RandomAccessFile(sName,"rw"); Pf6rr9  
this.nPos = nPos; I'BoP  
oSavedFile.seek(nPos); (SoV2[|  
} uwQ{y>SG  
O~9 %!LAu  
*FR Eh@R
 
public synchronized int write(byte[] b,int nStart,int nLen) }0?642 =-  
{ "Z }'u2%\m  
int n = -1;
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try{ 3w ?)H  
oSavedFile.write(b,nStart,nLen); +uKlg#wqc  
n = nLen; '\l(.N
 
} W )q^@6[d  
catch(IOException e) :doP66["!  
{ 3A4?9>g)KU  
e.printStackTrace (); kxhvy,t  
} -&M9Yg|Se  
7&:gvhw  
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return n; QZ"Lh  
} Bca\grA
 
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} Vg\EAs>f  
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0D/j2cT("k  
/* X
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**SiteInfoBean.java 0DIaXdOdW+  
*/ * ?rw'  
package NetFox; \5k[ "8~  
:!N 5daK  
X/];*='Q  
public class SiteInfoBean { _V1O =iu-  
UALwr>+VJ  
OlRBvfoh8  
private String sSiteURL; //Site's URL E[Tz%x=P  
private String sFilePath; //Saved File's Path tKo^A:M  
private String sFileName; //Saved File's Name IpoZ6DB$  
private int nSplitter; //Count of Splited Downloading File 4.|]R8Mn  
E6NkuBQ((  
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public SiteInfoBean() G! zV=p  
{//nSplitter的缺省值为5 2!-ZNd:(+  
//default value of nSplitter is 5 dU3UCD+2y  
this("","","",5); R6h(mPYA  
} oS/<)>\Gv  
p` B48TW  
8QE0J$d5  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ]B:g<}5$4  
{ :7e2O!zH_  
sSiteURL= sURL; R4_4FEo  
sFilePath = sPath; Um4 }`  
sFileName = sName; ?2 u_E "  
this.nSplitter = nSpiltter; *["9;_KD  
4G;+ETp  
@%O"P9;s  
} &0It"17Ej  
ot;j6eAH~E  
"k)( ,  
public String getSSiteURL() F8Rd#^9PD  
{ `D>PU@s$nT  
return sSiteURL; /wljbb/s  
} gkI(B2,/  
?#<Fxme  
R KFz6t  
public void setSSiteURL(String value) e/6WhFN#  
{ ipQJn_:2  
sSiteURL = value; d?oupW}uu  
} k*J}/HO  
(W
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public String getSFilePath() rG:IS=  
{ WQ\'z?P  
return sFilePath; f h)Cz)  
} x4CrWm  
~x)Awdlu  
o*_[3{FU  
public void setSFilePath(String value) A@Z&ZBDg  
{ 9b``l-rO  
sFilePath = value; Y1rU  
} "w*VyD  
_'ltz!~  
lf4-Ci*X  
public String getSFileName() 5,:>.LRA  
{ yc8iT`
 
return sFileName; #|v\UJ:Pf/  
} [uT&sZxmg  
izebQVQO*  
>to NGGU=~  
public void setSFileName(String value) N$aLCX  
{ :UoZ`O~  
sFileName = value; cWl  
} G!RbM.6  
Om0Z\GP=  
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public int getNSplitter() .2q7X{4=  
{ >2x[ub%$L  
return nSplitter; \zR@FOl`q  
} skh6L!6*<  
{VE\}zKF  
?[hIv6c  
public void setNSplitter(int nCount) -8-  
{ iOkRBi  
nSplitter = nCount; OIGu`%~js  
} \hai  
} EdlU}LU  
o9(:m   
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/* U$Z)v1&{  
**Utility.java )cJ9YKKy  
*/ L9M0vkgri  
package NetFox; O68/Hf1W  
}dQW-U  
@d:TAwOI'  
public class Utility { .:A9*,  
~2+J]8@I]  
:V*c9,>ZO  
public Utility() R*VRxQ,h6+  
{ 0"o%=i;  
kG@~;*;l  
LG0+A}E=C  
} Aj((tMJNOw  
FBJw (.Jr  
//线程睡眠 h)fJ2]JW8W  
public static void sleep(int nSecond) 3qwi)nm  
{ f40xS7-Q0  
try{ J5e  
Thread.sleep(nSecond); eLWD?-v%  
} L9ECF;)  
catch(Exception e) i eQQ{iGJH  
{ 8MqKS}\H  
e.printStackTrace (); Y` t-Bg!~  
} 6..G/,T
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} +AkAMZ"Mg  
TR}ztf[e  
//日志 Ox
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public static void log(String sMsg) Q
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{ }GI8p* ]o=  
System.err.println(sMsg); ZmU7tK  
} g:<2yT  
n=Qz7N(M  
F7[ 55RcP  
public static void log(int sMsg) F|9:$Jpw!  
{ 4+46z|  
System.err.println(sMsg); 0}v_usP  
} }\Kki  
} Jd#g"a>zZ  
|uL"/cMW7  
>F7v'-*{  
/*  {}x{OP  
**TestMethod.java 'PiQ|Nnb|  
*/ <uq#smY  
package NetFox; fP 4  
MoAZ!cF8  
,F^Rz.  
public class TestMethod { K`%{(^}.  
<;)qyP  
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public TestMethod() @px4[  
{ ///xx/weblogic60b2_win.exe luLt~A3H$  
try{ QxUsdF?p  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); fu 0]BdM  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 6IRzm6d  
SiteFileFetch fileFetch = new SiteFileFetch(bean); j\SvfZ0"  
fileFetch.start(); )S~ySiJ<U  
} .]gY{_|x  
catch(Exception e){e.printStackTrace ();} lJ y\Ky(*  
8"
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iH&BhbRu_  
} V'n4iM  
FH Hi/yh  
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public static void main(String[] args) &v}c3wL]  
{ U_\3preF  
new TestMethod(); R>|)-"b( `  
} `)Z+]5:  
} 1UyQ``v/  
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