http断点续传简单实现（java)

/* 6^p>f:5  
**SiteFileFetch.java ##NowO  
*/ +7)/SQM5  
package NetFox; w\.z-6G  
import java.io.*; <J1$s_^`  
import java.net.*; !3at(+4  
Lr(wS {  
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public class SiteFileFetch extends Thread { BtWm ZaKi  
j\@|oW0  
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SiteInfoBean siteInfoBean = null; //文件信息Bean oakm{I|k}  
long[] nStartPos; //开始位置 L@5g#mSl  
long[] nEndPos; //结束位置 Zo(QU5m0  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Uefw  
long nFileLength; //文件长度 obIYC  
boolean bFirst = true; //是否第一次取文件 h@?BA<'S  
boolean bStop = false; //停止标志 ;,_c1x/F  
File tmpFile; //文件下载的临时信息 ?jBh=X\]:  
DataOutputStream output; //输出到文件的输出流 POUD*(DqNK  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） y {1p#  
public SiteFileFetch(SiteInfoBean bean) throws IOException nxYp9,c"  
{ $3n@2 N`  
siteInfoBean = bean; (kI@U![u  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); .7GAGMNS  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ?r6uEZ  
if(tmpFile.exists ())
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{ V$ss[fX  
bFirst = false; b<rJ@1qtJ  
read_nPos(); _52BIrAO2  
} thSo,uGlW  
else )wYbcH  
{ e_pyjaY!s  
nStartPos = new long[bean.getNSplitter()]; M}6? |ir  
nEndPos = new long[bean.getNSplitter()]; $lrq*Nf9c  
} HPR*:t
 
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} ~v<,6BS<$Z  
u kKp,1xz  
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public void run() rRZ ,X%  
{ r5?qz<WW~  
//获得文件长度 7e-l`]  
//分割文件 KuO5`  
//实例FileSplitterFetch ]LhNP}c  
//启动FileSplitterFetch线程 A,qWg0A]nt  
//等待子线程返回 !Q5ip'
L  
try{ `#~HCl  
if(bFirst) 0SziTM  
{ G" Fd]'  
nFileLength = getFileSize(); ]jS+ItL@  
if(nFileLength == -1) k/#& ]8(  
{ fOyLBixR  
System.err.println("File Length is not known!"); m<;&B   
} .<`Rq'  
else if(nFileLength == -2) !>+Na~eN  
{ #_bSWV4  
System.err.println("File is not access!"); Ci ? +Sl  
} Qy@r&  
else o5FBqt  
{ obE_`u l#  
for(int i=0;i<nStartPos.length;i++) q|%(47}z  
{ ^\<1Y''  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); xe6 2gaT  
} daZY;_{"o  
for(int i=0;i<nEndPos.length-1;i++) ATU 2\Y  
{ =kvYE,,g_  
nEndPos = nStartPos[i+1]; >p 7e6%  
} RSY{I
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nEndPos[nEndPos.length-1] = nFileLength; cwxO| .m  
} &?<o692  
} 3RP}lb  
z<jWy$Ta;  
vF=d`T<  
//启动子线程 NY ZPh%x  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 89'XOX
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for(int i=0;i<nStartPos.length;i++) Z\y@rp\l  
{ eID"&SSU  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 'N0/;k0ax  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), )nS;]7pB@  
nStartPos,nEndPos,i); d\V\,%&.  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); PU^Z7T);  
fileSplitterFetch.start(); BS#@ehdig  
} f,Sybf/uHh  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), KPUc+`cN%  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); &k?Mt#J  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", <c{RY.1[  
nEndPos = " + nFileLength); RCq_FY  
// fileSplitterFetch[nPos.length-1].start(); KutR l$,
 
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tsZrn  
//等待子线程结束 J~:/,'Ea  
//int count = 0; mYN|)QVKy  
//是否结束while循环 Cj}1 )qWq  
boolean breakWhile = false; )A['+s  
.Tdl'y:..  
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while(!bStop) Px}#{fkS  
{ mMw&{7b:  
write_nPos(); U&/Jh^Yy  
Utility.sleep(500); W&6P%0G/  
breakWhile = true; B" wk:\zC  
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for(int i=0;i<nStartPos.length;i++) @M"h_Z1#  
{ pVw)"\S%  
if(!fileSplitterFetch.bDownOver) c|Nv^V*2  
{ d3(T=9;f2  
breakWhile = false; -iS\3P.  
break; mD)_quz.sk  
} oZ@_o3VG  
} Ajhrsa\~a  
if(breakWhile) gBq,So  
break; %?C{0(Z{  
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kO\(6f2|x  
//count++; JF_\A)<ki  
//if(count>4) 5sx-u!7  
// siteStop(); t_WNEZW7f  
} oG5JJpLT  
R{+Rvk  
3Cwqy#X#8  
System.err.println("文件下载结束！"); ~/hP6*  
} -X Bh\w  
catch(Exception e){e.printStackTrace ();} 1z$;>+g<  
} >0SF79-RE  
'UT 4x9&z  
~-6Kl3Y  
//获得文件长度 ~^IS{
1  
public long getFileSize() t@!X1?`w  
{ d"nE+pgE  
int nFileLength = -1; JB'q_dS}  
try{ w=3@IW  
URL url = new URL(siteInfoBean.getSSiteURL()); h&5H`CR[  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); JMOQDo  
httpConnection.setRequestProperty("User-Agent","NetFox"); dLal15Pb  
\A5cM\-  
VD+8j29  
int responseCode=httpConnection.getResponseCode(); H4 & d,8:m  
if(responseCode>=400) 4fZ$&)0&  
{ >&aFSL,f  
processErrorCode(responseCode); rG
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return -2; //-2 represent access is error xue-5 '  
} f 7et  
((Ec:(:c  
F1)Q#ThF\  
String sHeader; ,$sq]_t  
Hv<%_t_/  
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for(int i=1;;i++) iH( K[F /  
{ =2)5_/9au  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); OsAXHjX}  
//Utility.log(in.readLine()); czb(&><  
sHeader=httpConnection.getHeaderFieldKey(i); QO7> XHn  
if(sHeader!=null) 5}~*,_J2Z  
{ oFHVA!lqe  
if(sHeader.equals("Content-Length")) 91%+Bf()J6  
{ q[1H=+  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 1U~AupHE  
break; d^Ra1@0"q2  
}  #d*mG =  
} rr*",a"}m  
else @|%t<{y^I  
break; usR19_E-  
} JXGIVH?Rpu  
} av gGz8  
catch(IOException e){e.printStackTrace ();} Rmn|"ZK  
catch(Exception e){e.printStackTrace ();} X!CLOHVAa  
[lQp4xgxi  
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Utility.log(nFileLength); g 6>RyjN  
}`IN5NdYp  
,<|EoravH  
return nFileLength; )dJM  
} &EmxSYL>  
]NuY{T&:  
7l7eUy/z  
//保存下载信息（文件指针位置） vf~q%+UqK  
private void write_nPos() RXt`y62yK  
{ *2 4P T7  
try{ <jw`"L[D
 
output = new DataOutputStream(new FileOutputStream(tmpFile)); +sE81B  
output.writeInt(nStartPos.length); Vs8os+  
for(int i=0;i<nStartPos.length;i++) y*\ M7}](  
{ X&^t 8  
// output.writeLong(nPos); ~0|~Fg  
output.writeLong(fileSplitterFetch.nStartPos); L`x:Y>C(  
output.writeLong(fileSplitterFetch.nEndPos); Fmt5"3B  
} \@['V   
output.close(); rd0BvQ9TK  
} l8GziM{lp  
catch(IOException e){e.printStackTrace ();} \?GUGs  
catch(Exception e){e.printStackTrace ();} `\q4z-<-  
} j"_V+)SD  
p."pI Bd  
vV#Jl)
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//读取保存的下载信息（文件指针位置） +tdt>)a
 
private void read_nPos() (~}yt.7K  
{ =d7lrx+z  
try{ zBB4lC{q  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); "KW\:uc /  
int nCount = input.readInt(); &>@nW!n u  
nStartPos = new long[nCount]; /%Rz`}  
nEndPos = new long[nCount]; N^
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for(int i=0;i<nStartPos.length;i++) z mrk`o~  
{ uc=-+*D'I  
nStartPos = input.readLong(); 0l.+yr}PE  
nEndPos = input.readLong(); -q(,}/Xf  
} 4'Vuhqk  
input.close(); #rzxFMA"  
} a%;$l_wVT:  
catch(IOException e){e.printStackTrace ();} *J8j_-i,R  
catch(Exception e){e.printStackTrace ();} g}$]K!F  
} WsJ3zZc  
bW3e*O$V  

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private void processErrorCode(int nErrorCode) )f(#Fn  
{ -:a 9'dT  
System.err.println("Error Code : " + nErrorCode); 4rwfY<G  
} @ L%3}  
"]*0)h_  
S=krF yFw  
//停止文件下载 exTpy  
public void siteStop() eO(VSjo'`  
{ 1U@
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bStop = true; +To{Tm-  
for(int i=0;i<nStartPos.length;i++) Z\(+a
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fileSplitterFetch.splitterStop(); m,Q<4'  
2ztP'  
bzk@6jR1  
} 1xL2f&bG  
} RQ9fA1YP  
//负责部分文件的抓取 ?%;7k'0"  
**FileSplitterFetch.java %Ni)^   
*/ 46Nl];g1`  
package NetFox; tE3!;  
6}n_r}kNR  
i)+@'!6  
import java.io.*; ]*%0CDY6`N  
import java.net.*; wcsUb9(  
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public class FileSplitterFetch extends Thread { KNQX\-=  
b0PF7PEEQ  
QI=",vmau  
String sURL; //File URL SD8Q_[rY  
long nStartPos; //File Snippet Start Position V. =!^0'A  
long nEndPos; //File Snippet End Position ;[ pyKh  
int nThreadID; //Thread's ID Rzj5B\+Rk(  
boolean bDownOver = false; //Downing is over A$;U*7TJuO  
boolean bStop = false; //Stop identical eMPi ho  
FileAccessI fileAccessI = null; //File Access interface xo6-Y=c8  
Iy8Ehwejd  
`L]cJ0tAs  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException rzLpVpTaz  
{ c:>&Bg&,6T  
this.sURL = sURL; u~bk~3.I  
this.nStartPos = nStart; lyF~E  
this.nEndPos = nEnd; DN;g2R`f  
nThreadID = id; flR6^6E  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 qg'RD]a>R  
} ~>k<I:BtrT  
n0>#?ek12  
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public void run() GBHv| GO  
{ uPr@xff  
while(nStartPos < nEndPos && !bStop) +a"MSPC4w  
{ {"Van,w  
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",w@_}z:  
try{ ['tGc{4  
URL url = new URL(sURL); t}c ymX
~  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); BCJo/m  
httpConnection.setRequestProperty("User-Agent","NetFox"); fp.,MIS  
String sProperty = "bytes="+nStartPos+"-"; kHo0I8  
httpConnection.setRequestProperty("RANGE",sProperty); )_,*2|b  
Utility.log(sProperty); PUuxKW}  
\WQ\q \  
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InputStream input = httpConnection.getInputStream(); 5T:e4U&  
//logResponseHead(httpConnection); }XX)U_x  
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byte[] b = new byte[1024]; 1}Tbp_  
int nRead; +Hc[5WL  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ;;2XLkWu  
{ 5qt]~v%y  
nStartPos += fileAccessI.write(b,0,nRead); E2Q;1Re@  
//if(nThreadID == 1) mHM38T9C%
 
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); b" 1a7  
} FF0N{bY  
`J'xVq#O  
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Utility.log("Thread " + nThreadID + " is over!"); ?S~HnIn  
bDownOver = true; O6pswMhAc  
//nPos = fileAccessI.write (b,0,nRead); }JeG
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} ]e$mTRi*  
catch(Exception e){e.printStackTrace ();} M/EEoK^K@  
} P6u9Ngay  
} T&oY:1D,g  
[ %cW ?@  
a:r8Jzr  
//打印回应的头信息 f-F+Y`P  
public void logResponseHead(HttpURLConnection con) 3=RVJb  
{ |F=!0Id<  
for(int i=1;;i++) 9.{u2a\  
{ ({v$!AAv  
String header=con.getHeaderFieldKey(i); ^ |z|kc
 
if(header!=null) O:IU|INq8  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); JF!JY( U,  
Utility.log(header+" : "+con.getHeaderField(header)); Ew5(U`
]  
else j1Fy'os"!  
break; uUB,OmLN  
} umaF}}-Q{  
} Dq/_^a/1  
)a AKO`  
:.e`w#$7  
public void splitterStop() 9]<p  
{ i,r O3Jn  
bStop = true; z#ab V1 Xi  
} 5^<X:1J$  
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)_k"_VVcC  
} cKJf0S:cx-  
cXU8}>qY7  
w#vSZbh  
/* Zyt,D|eWj  
**FileAccess.java "(zvI>A  
*//文件访问(定位，写) #
tg,%*.s  
package NetFox; >Akrbmh5  
import java.io.*; 9>yLSM,!rS  
M<s16  
2~dUnskyy  
public class FileAccessI implements Serializable{ dn(I$K8  
[EI~/#;  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 }{T9`^V:h  
RandomAccessFile oSavedFile; %sxLxx_x!  
long nPos; 7r;7'X5  
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public FileAccessI() throws IOException Q&+Jeji  
{ F*m^AFjs  
this("",0); a~q_2S]h  
} nGQc;p5;  
8,B?!%FP  
%IrR+f+H  
public FileAccessI(String sName,long nPos) throws IOException eRU0gvgLu"  
{ zx` %)r  
oSavedFile = new RandomAccessFile(sName,"rw"); %J(y2 }  
this.nPos = nPos; l r80RL'_  
oSavedFile.seek(nPos); .1n=&d|  
} 701a%Jq_2  
1P4cBw%  
).U\,@[A{  
public synchronized int write(byte[] b,int nStart,int nLen) ^j]"!:h  
{ mN^w?R41m  
int n = -1; g_X-.3=2K  
try{ [.J&@96,b  
oSavedFile.write(b,nStart,nLen); wpgO09  
n = nLen; 1(%9)).K  
} p]h;M  
catch(IOException e) i7$4i|  
{ @Wgd(Ezd  
e.printStackTrace (); Lzmdy0!'  
} f@S n1c,Mk  
er@"4R0  
?QA![  
return n; F6 mc
<n  
} :rxS&5  
SnIH6k0T_  
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} v.iHgh  
?,s]5   
yP$@~L[!  
/* ~8 >Tb  
**SiteInfoBean.java (LiS9|J!  
*/ :ohGG ,`Dh  
package NetFox; a ?D]]0%  
zT<fTFJ1  
k;5$]^x  
public class SiteInfoBean { 42/MBP`
\Y  
(rKyX:Vsy  
{!RDb'Zp  
private String sSiteURL; //Site's URL f3yH4r?;w  
private String sFilePath; //Saved File's Path F/pq9  
private String sFileName; //Saved File's Name ')R+Z/hG.  
private int nSplitter; //Count of Splited Downloading File w8=&rzr8  
Vn&{yCm3  
cp1-eR_&  
public SiteInfoBean()
MzEeDN  
{//nSplitter的缺省值为5 zM+4<k_dH]  
//default value of nSplitter is 5 @jL](Mq|]  
this("","","",5); ~7p!t%;$  
} 5D]3I=kj  
^aG$9N<\  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) n[S-bzU^t  
{ \;XDPC j  
sSiteURL= sURL; ./]xn  
sFilePath = sPath; Q};n%&n&  
sFileName = sName; 7MWd(n-  
this.nSplitter = nSpiltter; 4nsc`Hu  
n!aA<  
1.9bU/X  
} (@DqKB  
!S.O~Kq  
,(u-q]8   
public String getSSiteURL() 8
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{ DCsamOA~  
return sSiteURL; *S xDwN  
} SFu]*II;
{  
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HNJR&U t  
public void setSSiteURL(String value) RWg'W,v=!  
{ /^]/ iTg  
sSiteURL = value; Ux,?\Vd  
} sYEh>%mo^C  
8Y]% S9.  
qX[{_$^Q  
public String getSFilePath() >&DC[)28  
{ pV8_i7\  
return sFilePath; a(J@]X>'  
} s.X .SJ  
N \~}`({  
')
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public void setSFilePath(String value) c@
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{ MzFFWk  
sFilePath = value; v9\U2j  
} Ucx"\/"  
z!M #  
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public String getSFileName() xH\!j  
{ eJ*u]GH U  
return sFileName; t$Bu<frQ  
} q+znb'i-x  
8J#U=q
Yei  
/[=Yv!  
public void setSFileName(String value) .@Lktc  
{ qzj.N$9]  
sFileName = value; yhkKakg,)  
} o;9 G{Xj3@  
_/czH<   
{Gr"lOi*@  
public int getNSplitter() z`qb>Y"xf3  
{ 0
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return nSplitter; eB&.
keO  
} "Xg~1)%  
;^TSla+t+  
2 \<u;9  
public void setNSplitter(int nCount) BM~6P|&qD  
{ *@{  
nSplitter = nCount; ?8do4gT+1  
} ECyG$j0  
} _l"=#i@L  
"38L ,PW0Z  
28LBvJVq@  
/* ~<.{z]*O  
**Utility.java /-knqv  
*/ 1CO
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package NetFox; ih|;H:"^  
DfU]+;AE  
x5Ue"RMl+
 
public class Utility { QuP)j1"X  
Z2L7US-  
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public Utility() v.-r %j{I  
{ D^QL.Du,  
K'}I?H~P_  
.kU}
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} U(PW$\l  
oTRidG  
//线程睡眠 A0>r]<y  
public static void sleep(int nSecond) i&1rf|  
{ c1q;  
try{ Gshy$'_e  
Thread.sleep(nSecond); EJP]E)  
} '6kD6o_p1  
catch(Exception e) E/hT/BOPK  
{ cij8'("+!  
e.printStackTrace (); oiIl\#C  
} Kx?.g#>U;  
} *;(^)Sj4Q  
}= wor~  
//日志 =:Yrb2gP_\  
public static void log(String sMsg) VP~(;H5%  
{ 52 *ii  
System.err.println(sMsg); lUaJC'~p  
} 33SCHQ  
cV"Ov@_.k  
=it@U/  
public static void log(int sMsg) qqJghV$Oj  
{ Yi]`"\  
System.err.println(sMsg); .hM t:BMf*  
} OTGy[jY"  
} Zb&pH~ 7  
!g`I*ZE+e  
w=CzPNRHH!  
/* q'/o=De  
**TestMethod.java o%f:BJS  
*/ n|pdYe8\  
package NetFox; *T#^|<.XG  
oY5`r)C7  
hj&~Dn(  
public class TestMethod { gkX7,J-0  
0VrsbkS  
{n&n^`Em  
public TestMethod() {/(.Bpld  
{ ///xx/weblogic60b2_win.exe (t\U5-
w  
try{ IRdR3X56  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 6O/c%1VHA3  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); )Fp$ *]|  
SiteFileFetch fileFetch = new SiteFileFetch(bean); S8B?uU  
fileFetch.start(); ZqdoYU'  
} nbB*d@"  
catch(Exception e){e.printStackTrace ();} , O/IY  
:5['V#(o  
u;]xAr1  
} 6" <(M@
 
]=%6n@z'  
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public static void main(String[] args) $Mj\ 3  
{ UM#.`  
new TestMethod(); {NQCe0S+p  
} Mvue>)g~>  
} $}r.fji,c  
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