http断点续传简单实现（java)

/* wQy~5+LE  
**SiteFileFetch.java `Ze$Bd\  
*/ iEtR<R>=  
package NetFox; @~ke=w6&pe  
import java.io.*; uVU)LOx  
import java.net.*; &M?b08  
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"M iJM+,  
public class SiteFileFetch extends Thread { U~ a\v8l~  
#btf|\D  
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SiteInfoBean siteInfoBean = null; //文件信息Bean pIK:$eN!/  
long[] nStartPos; //开始位置 :~"myn,  
long[] nEndPos; //结束位置 >^g2Tg:  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 8h=m()Eu  
long nFileLength; //文件长度 i3|xdYe$  
boolean bFirst = true; //是否第一次取文件 ]h`*w  
boolean bStop = false; //停止标志 ]FVJQS2h  
File tmpFile; //文件下载的临时信息 '62_q8:  
DataOutputStream output; //输出到文件的输出流 Het"x  
>fP;H}S6  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） d38o*+JCf  
public SiteFileFetch(SiteInfoBean bean) throws IOException :B5*?x  
{ nrev!h  
siteInfoBean = bean; %zGv+H?  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); LhAW|];  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); y]@JkF(  
if(tmpFile.exists ()) c;q=$MO`  
{ >&+V[srfD  
bFirst = false; l@GJcCufE  
read_nPos(); BSHS)_xs  
} |VaJ70\o  
else ER9{D$  
{ Lwi"K8.u  
nStartPos = new long[bean.getNSplitter()]; {u y^Bui}  
nEndPos = new long[bean.getNSplitter()]; uQ_C<ii"W  
} dI%jR&.e;  
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} o

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{c3FJ5:  
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public void run() )ddJ\:  
{ J2x}@p  
//获得文件长度 iupkb  
//分割文件 up['<Kt+a  
//实例FileSplitterFetch .>TG{>sH  
//启动FileSplitterFetch线程 FD E?O]^  
//等待子线程返回 3]kM&lK5\  
try{ VS ECD;u4c  
if(bFirst) ,h1\PT9ULY  
{ I>nYI|o1  
nFileLength = getFileSize(); V]J"v#!{  
if(nFileLength == -1) !\{2s!l~  
{ ^cPVnl  
System.err.println("File Length is not known!"); #'KM$l,P  
} E-Xz  
else if(nFileLength == -2) @a]cI  
{ %>+lr%B  
System.err.println("File is not access!"); :^`j:B  
} &D[M<7T  
else y>t:flD*  
{ \i,H1a  
for(int i=0;i<nStartPos.length;i++) x*F-d2D  
{ 46)[F0,$r  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Ws3z-U>j  
} rG~W=!bj  
for(int i=0;i<nEndPos.length-1;i++) \9p.I?=  
{ Ih5Y7<8b~  
nEndPos = nStartPos[i+1]; U3B&3K} ~  
} =/a`X[9vI  
nEndPos[nEndPos.length-1] = nFileLength; 5|eX@?QF58  
} 8i;drvf  
} N e{=KdzT  
rMJ@oc  
v `/nX->  
//启动子线程 -a_qZ7  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; \6a' p Q,  
for(int i=0;i<nStartPos.length;i++) mIG>`7`7N  
{ ulN1z  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 1yF9zKs&_  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), H74'I}  
nStartPos,nEndPos,i); p@Os  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); H(n fHp.3  
fileSplitterFetch.start(); "Y^Fn,c  
} 3
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// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 11QZ- ^  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); & ;5f/  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", KQ9w>!N[  
nEndPos = " + nFileLength); dbEXlm  
// fileSplitterFetch[nPos.length-1].start(); EmUt/]  
+|S)Mm8-  
:n~Mg{j3  
//等待子线程结束 Z-CA9&4Uh  
//int count = 0; }T}c%p  
//是否结束while循环 wsrdBxd5  
boolean breakWhile = false; !p\ @1?  
Iw?^  
#+6j-^<_6  
while(!bStop) M-Vz$D/aed  
{ J:uFQWxZ   
write_nPos(); ) xV>Va8)  
Utility.sleep(500); ;dZZOocV1  
breakWhile = true; 3VMaD@nYa  
[m< jM[w{  
^oC>,%7  
for(int i=0;i<nStartPos.length;i++) *j,noHUT~>  
{ h8.(Q`tli  
if(!fileSplitterFetch.bDownOver) (]mBAQ#hw  
{ |,n(9Ix  
breakWhile = false; !Y UT*  
break; _z]v;Q  
} ?t\GHQ$$?  
} L28wT)D-  
if(breakWhile) G^<m0ew|  
break; m>[G-~0?kI  
$@{d\@U  
15|gG<-  
//count++; \N?lG q  
//if(count>4) $i8oLSRV  
// siteStop();  874j9ky[  
} ri3*~?k00  
I`@>v%0  
56C'<#  
System.err.println("文件下载结束！"); c2GTN"  
} tQxAZ0B^  
catch(Exception e){e.printStackTrace ();} SJ8 ~:"\P  
} [UdJ(cGf  
@Py'SH!-  
+m}D.u*cp  
//获得文件长度 /NPx9cLW^  
public long getFileSize() bS|h~B]rd  
{ vsA/iH.  
int nFileLength = -1; Y>nQ<  
try{ ?g
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URL url = new URL(siteInfoBean.getSSiteURL()); A5}N[|z  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); A$P Oc<  
httpConnection.setRequestProperty("User-Agent","NetFox"); :%fnJg(
 
|t$%kpp  
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int responseCode=httpConnection.getResponseCode(); /^si(BuC^*  
if(responseCode>=400) bWCtRli}  
{ "0>AefFd#  
processErrorCode(responseCode); JGhK8E  
return -2; //-2 represent access is error s/;S2l$`  
} nGJ+.z  
X*)DpbWd  
"[_gRe*2  
String sHeader; +WxD=|p;  
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se_Oi$VZ{  
for(int i=1;;i++) oC!z
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{ *L<<S=g$2  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); O+DYh=m*p  
//Utility.log(in.readLine()); EUPc+D3  
sHeader=httpConnection.getHeaderFieldKey(i); &]KA%Db2  
if(sHeader!=null) )DQcf]I  
{ R C!~eJG!  
if(sHeader.equals("Content-Length")) '2p,0Bk9i  
{ ( ~>-6Nb 5  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); cGg~+R2P  
break; )h%tEY$
AJ  
} IV`+B<3  
} pe\]}&  
else #("E)P  
break; N
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} UQT=URS  
} Qyj:!-o  
catch(IOException e){e.printStackTrace ();} ~NK|q5(I  
catch(Exception e){e.printStackTrace ();} &x[V<
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%$R]NL|  
Utility.log(nFileLength); p"Di;3!y!  
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return nFileLength; }SW>ysw'm  
} FCt %of#  
N<HJ}geC"  
[:{HX U7y  
//保存下载信息（文件指针位置） l4E0/F  
private void write_nPos() Gd[:&h  
{ D'_w *  
try{ _s0;mvz'  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Yc>.P  
output.writeInt(nStartPos.length); =|3*Y0  
for(int i=0;i<nStartPos.length;i++) y>JSo9[@  
{ cs Gd}2V
E  
// output.writeLong(nPos); ]RI+:f  
output.writeLong(fileSplitterFetch.nStartPos); KN\tRE  
output.writeLong(fileSplitterFetch.nEndPos); ]6?6 k4@  
} `+T"^{ Z  
output.close(); -h&KC{Xab  
} oMb@)7
 
catch(IOException e){e.printStackTrace ();} V.kf
@  
catch(Exception e){e.printStackTrace ();} R\lUE,o]<q  
} Wtj*Z.=:  
qZh}gu*>  
z7O$o/E-*  
//读取保存的下载信息（文件指针位置） c"S{5xh0&  
private void read_nPos() 2?(dS  
{ p y%RR*4#  
try{ X:OUu;  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Jw -3G3h  
int nCount = input.readInt(); /G!M\teeF  
nStartPos = new long[nCount]; jtQ}   
nEndPos = new long[nCount]; <3[0A;W=1  
for(int i=0;i<nStartPos.length;i++) *skmTioj&  
{ 0{.[#!CSk  
nStartPos = input.readLong(); o+FDkqEN  
nEndPos = input.readLong(); ![aa@nOSa  
} CdNb&Nyz  
input.close(); 3|1v)E  
} 63pd W/\j  
catch(IOException e){e.printStackTrace ();} ]R]%c*tA  
catch(Exception e){e.printStackTrace ();} '0jn|9l58  
} _ v3VUm#  
*f3?0w  
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private void processErrorCode(int nErrorCode) /yTPb  
{ Na$[nv8qh  
System.err.println("Error Code : " + nErrorCode); Ws:MbZyr  
} 5/m}v'S%  
'DtC=  
9%^O-8!  
//停止文件下载 <4%vl+qW  
public void siteStop() |sPUb;&~  
{ o6)U\z  
bStop = true; >AUzsQ  
for(int i=0;i<nStartPos.length;i++) ow K)]t  
fileSplitterFetch.splitterStop(); fsUZG6  
VqnM>||  
F%G} >xn  
} `clp#l.ii  
} a<lDT_2b  
//负责部分文件的抓取 9}aEV 0 V|  
**FileSplitterFetch.java i&\cDQ 3  
*/ O#x=iZI  
package NetFox; -s9()K(vZG  
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t-)d*|2n}o  
import java.io.*; zAH6SaI$  
import java.net.*; cng166}1A  
Pd;Gc@'~  
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public class FileSplitterFetch extends Thread { 4XIc|a Aa  
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w L4P-4'  
String sURL; //File URL eR:C?v  
long nStartPos; //File Snippet Start Position EjP9/VG@=  
long nEndPos; //File Snippet End Position d
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int nThreadID; //Thread's ID ~
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boolean bDownOver = false; //Downing is over Ar'k6NX  
boolean bStop = false; //Stop identical %`}nP3  
FileAccessI fileAccessI = null; //File Access interface 5+
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/o9 0O&  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException )8;At'q}  
{ x%T.0@
!8  
this.sURL = sURL; 1G)I|v9R  
this.nStartPos = nStart; 5Kw?#  
this.nEndPos = nEnd; |G/WS0  
nThreadID = id; -9(pOwN |m  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 fw)Q1"|  
} }/MmuPp  
(h'Bz6K  
aATNeAR  
public void run() L5r02VzbD
 
{ DcN!u6sJ  
while(nStartPos < nEndPos && !bStop) 'zOB!QqA`v  
{ U<<XeSp  
bD.KD)5  
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try{ 8&yI1XM|  
URL url = new URL(sURL); 17-B'Gl!<%  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); B_ bZ
a  
httpConnection.setRequestProperty("User-Agent","NetFox"); :Q8*MJ3&V  
String sProperty = "bytes="+nStartPos+"-"; ~bsdy2&/q  
httpConnection.setRequestProperty("RANGE",sProperty); D!&]jkUN  
Utility.log(sProperty); I>{o]^xw-D  
6B+?X5-6DH  
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InputStream input = httpConnection.getInputStream(); aNP\Q23D  
//logResponseHead(httpConnection); d'iSvd.  
<Yg6=e  
~ +h4i'  
byte[] b = new byte[1024]; a[p$e?gka  
int nRead; 8*Ty`G&v  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) S_?sJwM  
{ MV]`[^xQ5  
nStartPos += fileAccessI.write(b,0,nRead); oRZe?h^r#  
//if(nThreadID == 1) J&&)%&h'I  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); NS-0-o|4#  
} Iw?*y.z|  
\i+Ad@)  
&OA6Zw/A  
Utility.log("Thread " + nThreadID + " is over!"); FC WF$'cO  
bDownOver = true; uU%Z%O  
//nPos = fileAccessI.write (b,0,nRead); YQb503W"d~  
} sDAP'&  
catch(Exception e){e.printStackTrace ();} ubRhJ~XB  
} BS(jC  
} q;*'V9#  
bM.$D-?dF*  
e=3C*+lq\  
//打印回应的头信息 2_ 1RJ
 
public void logResponseHead(HttpURLConnection con) &XCP@@T  
{ 8 Vf#t!t  
for(int i=1;;i++) f@[)*([  
{ TU':Rt  
String header=con.getHeaderFieldKey(i); UA4c4~$S  
if(header!=null) T?RN} @D  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); aRElk&M  
Utility.log(header+" : "+con.getHeaderField(header)); ]>1`Fa6_  
else :,fT^izew  
break; ^VW]Qr!  
} $B7c\MR j  
} r+h%a~A#>  
oUO3,2bn  

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public void splitterStop() ]#W7-Q;]  
{ ?XP4kjJ  
bStop = true;  ;u[:J  
} [+QyKyhTO  
0U:X[2|)  
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} v 2p  
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m.!LL]]  
/* 5*+DN U@  
**FileAccess.java `Tf}h8*  
*//文件访问(定位，写) LT>_Y`5>  
package NetFox; d2V\T+=  
import java.io.*; P{9wJ<  
8)>T>-os  
dQ~GE}[  
public class FileAccessI implements Serializable{ cJbv,RV<  
tzfyS#E  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 qA\&%n^j]  
RandomAccessFile oSavedFile; ,X1M!'  
long nPos; ah f,- ?S  
U<;{_!]  
{[`(o 0@(  
public FileAccessI() throws IOException ^*4#ZvpG2  
{ mtkZF{3Jx  
this("",0); QV.>Cy  
} a'/C)fplL  
A
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J%|;  
public FileAccessI(String sName,long nPos) throws IOException _>]/.w2=  
{ Y0kcxpK/  
oSavedFile = new RandomAccessFile(sName,"rw"); `xHpL8i$5  
this.nPos = nPos; 8(l0\R,%+z  
oSavedFile.seek(nPos); ZMZWO$"K1  
} YgjW%q   
aMGh$\Pg  
fZr{x$]N0  
public synchronized int write(byte[] b,int nStart,int nLen) qTRP2rH,L&  
{ rPBsr<k#5  
int n = -1; :RukW.MR  
try{ DJ7ak>
"R  
oSavedFile.write(b,nStart,nLen); qdwo2u  
n = nLen; wJJ|]^0.  
} #<B?+gzFM{  
catch(IOException e) +X+R8  
{ ~Q Q1
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e.printStackTrace (); 568M4x
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} :Zkjtr.\  
<dE~z]P  
==?%
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return n; #:yAi_Ct  
} Z.Z31yF:f  
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} ZL0k  
LgX2KU"  
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/* a6ryyt 5  
**SiteInfoBean.java .pe.K3G&  
*/ /6[vF)&  
package NetFox;
c)N_"#&  
bA Yp }  
2B6u) 95  
public class SiteInfoBean { 7Dl^5q.|  
B/K=\qmm  
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private String sSiteURL; //Site's URL 4IB`7QJq  
private String sFilePath; //Saved File's Path n} !')r  
private String sFileName; //Saved File's Name {yT<22Fl  
private int nSplitter; //Count of Splited Downloading File @ YWuW
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] s 2ec  
[]N&,2O  
public SiteInfoBean() g0a!auWM  
{//nSplitter的缺省值为5 k5bv57@  
//default value of nSplitter is 5 qFDy)4H)  
this("","","",5); 2,B^OZmw  
} pp*MHM)x|q  
ASMItT  
}3XjP55  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter)
s5{H15  
{ xDekC~Zq  
sSiteURL= sURL; 9"1=um=  
sFilePath = sPath; oz:J.<j24Z  
sFileName = sName; ujX
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this.nSplitter = nSpiltter; /i Xl]<  
1yU!rEH  
I 6<LKI/  
} U:MZN[Cc[  
FU}- .Ki  
e*( _Cvxp  
public String getSSiteURL() iK'A m.o+  
{ p((.(fx  
return sSiteURL; T}XJFV  
} r[kHVT8  
Ud>hDOJ3  
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public void setSSiteURL(String value) e*Nm[*@UW  
{ UQ^ )t ]  
sSiteURL = value; 98<^!mwF  
} _Bn8i(  
5y0LkuRR:  
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public String getSFilePath() }!s$ /Kn  
{ r[j@@[)"  
return sFilePath; I]m&h!  
} cx)x="c  
l~kxK.Ru  
b_~KtMO  
public void setSFilePath(String value) &\/}.rF  
{ rHjR 4q  
sFilePath = value; }_Sg
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} ;%u)~3B$JK  
W"xRf0\V
 

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public String getSFileName() #?\|)y4i  
{ cetlr  
return sFileName; uA%F0oM  
} )GC[xo4bg  
6XVJ/q
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\nVoBW(  
public void setSFileName(String value) zq#gf  
{ *qIns/@  
sFileName = value; +w@/$datI  
} O}lqY?0*  
n^epC>a"b  
$:DhK  
public int getNSplitter() _j_c&  
{ QO,ge<N+N  
return nSplitter;  bqR0./V  
} OPKmYzf@b  
90$`AMR  
]b&
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public void setNSplitter(int nCount) V3\}]5  
{ !{oP'8Ax$  
nSplitter = nCount; >LR+dShG  
} kca  Y  
} pC)S
9Kl  
qSL~A-  
UDa\*  
/* 04z2gAo  
**Utility.java GwlAEhP  
*/ pM@0>DVi  
package NetFox; H*dQTy,  
kI$X~s$r  
MXpj_+@  
public class Utility { ( e(<4-&  
<.6$zcW  

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public Utility() ;0++):30V  
{ }
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8,
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} 8c'E  
DcLx[C  
//线程睡眠 j2{ '!  
public static void sleep(int nSecond) $;+`sVG  
{ Bbx.RL.V  
try{ "PPn^{bYm  
Thread.sleep(nSecond); [kq+a]q  
} [5kaF"  
catch(Exception e) C{):jH,Rf  
{ v~>4c<eG  
e.printStackTrace (); -{fbZk&A  
} +EgQj*F*  
} %7rWebd-  
^k?Ig.m  
//日志 <El6?ml@  
public static void log(String sMsg) F D6>[W  
{ Kth^WHL  
System.err.println(sMsg); )zVD!eG_9  
} "ealYve
u  
"n@=.
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mYzq[p_|j  
public static void log(int sMsg) C"ZCX6p+$  
{ 7nHlDPps)  
System.err.println(sMsg); XA:v:JFS  
} /z+}xRS  
} `795K8  
%k3a34P@  
5fBW#6N/  
/* u37@9  
**TestMethod.java %8+'L4  
*/ "U&
 
package NetFox; PF- sb&q  
S<LHNZu|^A  
PTvP;  
public class TestMethod { D|n`9yv a  
w_I}FPT<(:  
2,<!l(X  
public TestMethod() w]\O3'0Js  
{ ///xx/weblogic60b2_win.exe LE!3'^Zq  
try{ c>r0N[  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); {j E}mzi  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 3&-BO%i
 
SiteFileFetch fileFetch = new SiteFileFetch(bean); h^bbU.  
fileFetch.start(); F/}PN1#T  
} ^r$P&}Z\b  
catch(Exception e){e.printStackTrace ();} [ua{qJ9  
Jh[fFg]  
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} b07 MTDFH7  
-q\1Tlc]3  
/'}O-h  
public static void main(String[] args) 9[B*CD|  
{ V5RfxWtm:  
new TestMethod(); aC$hg+U$G  
} ek#{!9-  
} f|_iHY  
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