http断点续传简单实现（java)

/* 2eC`^  
**SiteFileFetch.java xxy (#j$  
*/ #!.26RM:P  
package NetFox; ]9A@iA  
import java.io.*; SHow~wxw  
import java.net.*; vQH6CB"  
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public class SiteFileFetch extends Thread { ]S0tK  
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SiteInfoBean siteInfoBean = null; //文件信息Bean [[XbKg`"?  
long[] nStartPos; //开始位置 wjzR 8g0bQ  
long[] nEndPos; //结束位置 |7#S0Ca@  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 r+RFDg/  
long nFileLength; //文件长度 ~7 w"$H8  
boolean bFirst = true; //是否第一次取文件 2/dvCt6 N  
boolean bStop = false; //停止标志 0 k(su  
File tmpFile; //文件下载的临时信息 8el\M/u{  
DataOutputStream output; //输出到文件的输出流 uD=FTx  
*`]#ntz9  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ITssBB9  
public SiteFileFetch(SiteInfoBean bean) throws IOException /LK,:6  
{ 2%Mgg,/~  
siteInfoBean = bean; $-w&<U$E  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); "7z1V{ ;Y  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info");  j1~'[  
if(tmpFile.exists ()) Mn<#rBE B  
{ e+~Q58oD  
bFirst = false; L,\wB7t  
read_nPos(); b[/uSwvi  
} ^]zC~LfG  
else ']&rPvkL  
{ zz m[sX}  
nStartPos = new long[bean.getNSplitter()]; x{_3/4  
nEndPos = new long[bean.getNSplitter()]; q)f-z\  
} w7E7r?)Wl|  
Ze.\<^-t  
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} }7HR<%<7  
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public void run() +1pY^#A  
{ 5H^"  
//获得文件长度 BG9.h!  
//分割文件 h0z>dLA#2  
//实例FileSplitterFetch JwNB)e D  
//启动FileSplitterFetch线程 WV&grG|
 
//等待子线程返回 V48o+O  
try{ PRi1 `%d  
if(bFirst) Dt~ |)L+  
{ /%{
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nFileLength = getFileSize(); "8l&m6`U-  
if(nFileLength == -1) b?]Lx.l-  
{ /H'F4->  
System.err.println("File Length is not known!"); [bh8Nj\E  
} /^\UB fE  
else if(nFileLength == -2) U9t-(`[j?  
{ I&JjyR  
System.err.println("File is not access!"); &UxI62[k  
} H"vkp~u]I  
else ,!>1A;~wT  
{ cCBYM  
for(int i=0;i<nStartPos.length;i++) G
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{ mx=2lL`  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); xgq `l#  
} n6C]JWG\/U  
for(int i=0;i<nEndPos.length-1;i++) _%gu<Ys  
{ EQ%,IK/  
nEndPos = nStartPos[i+1]; De`p@`+<#~  
} 5H79-QLd  
nEndPos[nEndPos.length-1] = nFileLength; = P@j*ix  
} |y$8!*S~(  
} | k?r1dj%O  
i$gH{wn\`  
]t)#,'$^[W  
//启动子线程 `|`Qrv4}  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ,a'Y^[4k?  
for(int i=0;i<nStartPos.length;i++) J^gElp  
{ v[XTH 2  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), _eZ*_H,\  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Ql]+,^kA@  
nStartPos,nEndPos,i); ~]V}wZt>h  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 8nE}RD7bx  
fileSplitterFetch.start(); 0K'^g0G  
} ]AB'POa  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), rH
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); FMEW['  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", k0@*Up3{7  
nEndPos = " + nFileLength); BN%;AQV  
// fileSplitterFetch[nPos.length-1].start(); [Ol~}@gV  
,GUOq!z  
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//等待子线程结束 N9cCfB\`  
//int count = 0; U["-`:>jfp  
//是否结束while循环 DkJ "#8Yl=  
boolean breakWhile = false; JU3to_Io  
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0WI@BSHnM  
while(!bStop) HY2*5#T  
{ 7'zXf)!  
write_nPos(); g:eqB&&  
Utility.sleep(500); ^\Epz*cL  
breakWhile = true; e1/{bX5  
AU4K$hC^  
t.pn07$  
for(int i=0;i<nStartPos.length;i++) z(eAhK}6?  
{ AlA:MO]NM  
if(!fileSplitterFetch.bDownOver) f)19sjAJk  
{ ~A@HW!*
Z@  
breakWhile = false; ,X}Jpi;/  
break; wAKm]?zB>  
} Bdr'd? u<A  
} >K n7A  
if(breakWhile) &>A<{J@VL  
break; i_f\dkol  
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Ox%p"xuP,  
//count++; (sqI:a  
//if(count>4) e#odr{2#4u  
// siteStop(); *!MMl]gU?  
} 2bu>j1h  
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m[DCA\Mo@  
System.err.println("文件下载结束！"); 9>k_z&<  
} 4l'`q+^-  
catch(Exception e){e.printStackTrace ();} *2>kic aH  
} W9!K~
g_  
{RC&Ub>  
:5[1Iepdn  
//获得文件长度 K_ Odu^  
public long getFileSize() v3b+Ddp  
{ DHQs_8Df  
int nFileLength = -1; <O0
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try{ 3|(<]@ $  
URL url = new URL(siteInfoBean.getSSiteURL()); t.Yf8Gy  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); (v}4,'dS  
httpConnection.setRequestProperty("User-Agent","NetFox"); K~6u5a9s  
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T#.pi@PF>  
int responseCode=httpConnection.getResponseCode(); Ajm4q_
  
if(responseCode>=400) 'E"W;#%  
{ :nS$cC0x*  
processErrorCode(responseCode); u{&#Gci  
return -2; //-2 represent access is error 2EiE5@  
} $X,dQ]M  
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+~$pkxD"  
String sHeader; G^Va$ike  
Mp?L9  

hsHbT^Qm  
for(int i=1;;i++) 8Dkq+H93  
{ ,lcSJ^yr  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Y?ZzFd,i&  
//Utility.log(in.readLine()); NXX/JJ+w  
sHeader=httpConnection.getHeaderFieldKey(i); z/,&w_8,:  
if(sHeader!=null) B \LmE+a>  
{ SW}?y%~  
if(sHeader.equals("Content-Length")) `\$EPUM  
{ MdDL?ev  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 5?q6g  
break; Y94S!TbB  
}
Z&of-[)  
} &B\ sG=  
else 0X:$ASocU  
break; Y@Ur}  
}
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} K3k{q90   
catch(IOException e){e.printStackTrace ();} h [@}}6  
catch(Exception e){e.printStackTrace ();} Lp)P7Yt-  
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Utility.log(nFileLength); 14DhJUV"b  
8Si3 aq3  
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return nFileLength; Ab6R?mUM  
} 2ZEDyQM  
b
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@'<=EAXe  
//保存下载信息（文件指针位置） qrf90F)  
private void write_nPos() J7Mbv2
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{ IN75zn*%  
try{ Tje(hnN  
output = new DataOutputStream(new FileOutputStream(tmpFile)); -3u ;U,}  
output.writeInt(nStartPos.length); <eZ*LK?  
for(int i=0;i<nStartPos.length;i++) [HI$[:[  
{ U!(es0rX  
// output.writeLong(nPos); _2Mpzv  
output.writeLong(fileSplitterFetch.nStartPos); U C_$5~8p  
output.writeLong(fileSplitterFetch.nEndPos); GvZ[3GT  
} {isL<  
output.close(); 2u$r
loc$b  
} W{c Z7$d  
catch(IOException e){e.printStackTrace ();} GVhy }0|  
catch(Exception e){e.printStackTrace ();} )<lQJ#L86a  
} z'7XGO'Lo  
~1{ppc+  
p-r[M5;-^Q  
//读取保存的下载信息（文件指针位置） MdN0 Y@Ll  
private void read_nPos() F
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{ 2;(+]Ad<  
try{ w+wtr[;wwL  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); d<6m_!L  
int nCount = input.readInt(); CXi[$nF3  
nStartPos = new long[nCount];  md,KRE  
nEndPos = new long[nCount]; A$i^/hJs  
for(int i=0;i<nStartPos.length;i++) q[GDK^-g  
{ LmytO$?2(  
nStartPos = input.readLong(); fm L8n<1  
nEndPos = input.readLong(); d8iq9AP\o  
} 6bPl(.(3  
input.close(); 0U~*uDU  
} Mi;Pv*  
catch(IOException e){e.printStackTrace ();} o{hX?,4i  
catch(Exception e){e.printStackTrace ();} B$n1k45  
} SgYMPBh  
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private void processErrorCode(int nErrorCode) :yRv:`r3Lt  
{ yO}5.  
System.err.println("Error Code : " + nErrorCode); lu8*+.V  
} 3=yfbO<-  
tcO{CI  
Z #T  
//停止文件下载 050,S`%<g8  
public void siteStop() ]x{.qTtw  
{ Lx tgf2r  
bStop = true; @mmnr?_w  
for(int i=0;i<nStartPos.length;i++)
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fileSplitterFetch.splitterStop(); y/5GY,z%aL  
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} .
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} #?V rt,n  
//负责部分文件的抓取 Inn{mmz 1  
**FileSplitterFetch.java %pxO<O  
*/ *\(z"B  
package NetFox; +VNk#Z i  
=~k c7f{  
9?8PMh.  
import java.io.*; b+|3nc!  
import java.net.*; 2:_6nWl  
=#v? }JG  
fvcS=nR
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public class FileSplitterFetch extends Thread { ?^M,Mt  
*yaS^k\  
0y6M;"&~E  
String sURL; //File URL &!OEd]  
long nStartPos; //File Snippet Start Position dFF
=-_O>  
long nEndPos; //File Snippet End Position yIrJaS-  
int nThreadID; //Thread's ID eZaSV>27  
boolean bDownOver = false; //Downing is over I/%v`[  
boolean bStop = false; //Stop identical  ?C#E_  
FileAccessI fileAccessI = null; //File Access interface GB35ouE  
#c
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N+h05`  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException l?=\9y  
{ jj1\
oyQ8  
this.sURL = sURL; '3Lu_]I-  
this.nStartPos = nStart; OQ7 `n<I<)  
this.nEndPos = nEnd; .w;kB}$YC  
nThreadID = id; -^5467  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 K)BQ0v.:[  
} 0/b  _T  
h%krA<G9  
t*=[RS*  
public void run() ](A2,F 9(U  
{ T*f/M  
while(nStartPos < nEndPos && !bStop) >WIc"y.  
{ xbm%+  

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try{ %VH,(}i  
URL url = new URL(sURL); nuXL{tg6  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); =o~GLbsER  
httpConnection.setRequestProperty("User-Agent","NetFox"); sVK?sBs]  
String sProperty = "bytes="+nStartPos+"-"; p,goYF??  
httpConnection.setRequestProperty("RANGE",sProperty); lQ-<T<g  
Utility.log(sProperty); Jsysk $R  
!R"W2Z4h  
\gk.[={^P  
InputStream input = httpConnection.getInputStream(); -}9^$}PR  
//logResponseHead(httpConnection); mAtqF %V  
EU%,tp   
^>?=L\[  
byte[] b = new byte[1024]; !:^q_q4  
int nRead; %'yrIR  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) <;6{R#Tuh  
{ {]< G=]'  
nStartPos += fileAccessI.write(b,0,nRead); }=5>h' <  
//if(nThreadID == 1) eHuJFM  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); M'PZ{6;  
} njF$1? )sq  
Lr:Qc#2  
?: yz/9(  
Utility.log("Thread " + nThreadID + " is over!"); {aUnOyX_  
bDownOver = true; [mA-s
l]  
//nPos = fileAccessI.write (b,0,nRead); A^>@6d $2  
} G{3|d/;Bt  
catch(Exception e){e.printStackTrace ();} O\ZC$XF  
} G aV&y  
} IWQ0I&tzdx  
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//打印回应的头信息 y|2<Vc  
public void logResponseHead(HttpURLConnection con) x,!Dd  
{ @kW
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for(int i=1;;i++) +e-F`k  
{ x#J9GP.  
String header=con.getHeaderFieldKey(i); gSz<K.CT  
if(header!=null) x9"Cm;H%  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); }OpUG  
Utility.log(header+" : "+con.getHeaderField(header)); STp9Gh-  
else RpQeQM=  
break; vR!+ 8sy$  
} QQM:[1;RT  
} kAQ(8xV  
"lI-/G  
V4:/LNq_]  
public void splitterStop() Io1j%T#ZT  
{ eQuu\/z*H  
bStop = true; 5#,H&ui\  
} Vxh39eW  
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} "' JnFM  
/MGapmqV9  
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/* ~U0%}Bbh  
**FileAccess.java Qt>K{ >9Cf  
*//文件访问(定位，写) l88=  
package NetFox; 2R[v*i^S  
import java.io.*; a!9'yc  
b=
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#ibwD:{  
public class FileAccessI implements Serializable{ fp)SZu_*  
 g2vm]j  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 U?*zb  
RandomAccessFile oSavedFile; 3~~X,ZL  
long nPos; Mg;pNK\n  
~_
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public FileAccessI() throws IOException ]pn U"  
{ |U%NPw5  
this("",0); 'J,UKK\5  
} LwC?t3n
 
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qGk.7wf%  
public FileAccessI(String sName,long nPos) throws IOException k=]e7~!  
{ Zhfp>D  
oSavedFile = new RandomAccessFile(sName,"rw"); Uwc%'=@  
this.nPos = nPos; Lce,]z\_  
oSavedFile.seek(nPos); g\q .  
} xMJ-=  
.xT?%xSi/  
(a[BvJf  
public synchronized int write(byte[] b,int nStart,int nLen) @t%da^-HS"  
{ .U!EA0B  
int n = -1; p<mL%3s0  
try{ :Y99L)+=/  
oSavedFile.write(b,nStart,nLen); cNWmaCLN$  
n = nLen; $*C }iJsF  
} w2s`9  
catch(IOException e) WLUgiW(0$  
{ T3wTMbZ!VK  
e.printStackTrace (); :zHSy&i`  
} q"VmuQ  
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return n; \.i7(J]  
} '12m4quO  
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} )s!A\a`vEd  
,U{dqw8E{  
+^AdD8U  
/* opfnIkCe  
**SiteInfoBean.java /TMVPnvz.  
*/ F5*-HR  
package NetFox; ]46h!@~aC  
v;(cJ,l  
V IzIl\<aM  
public class SiteInfoBean { C*YQ{Mz(f  
(JbRhcg  
+6WjOcu  
private String sSiteURL; //Site's URL dn h qg3Y  
private String sFilePath; //Saved File's Path .\b.l@O<Z  
private String sFileName; //Saved File's Name b `P6Ox3  
private int nSplitter; //Count of Splited Downloading File jJ2rfdfj  
6()Jx%  
!X}+JeU'  
public SiteInfoBean() MT{1/A;`)  
{//nSplitter的缺省值为5 *
).  
//default value of nSplitter is 5 z 0?MeH#  
this("","","",5); [J2evi?  
} zZ[kU1Fyv  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Hcf"u&%  
{ Y1Ql_  
sSiteURL= sURL; {MtJP:8Jp  
sFilePath = sPath; RPX.?;":  
sFileName = sName; \#[DZOI~  
this.nSplitter = nSpiltter; [vr"FLM|9  
 ]!ZZRe  
_N5pxe`  
} 27Gff(  
|;J`~H"K  
1feVFRx'  
public String getSSiteURL() Sstz_t  
{ BsA4/Bf  
return sSiteURL; Bl>m`/\1i  
} ;1~n|IY  
DcxT6[  
5%TSUU+<I  
public void setSSiteURL(String value) &&;.7E  
{ s(X\7Hz_nC  
sSiteURL = value; `C4(C4u  
} >:.c?{%g*  

^2dQVV.  
x}ZXeqt{{  
public String getSFilePath() @0@WklAJA  
{ /
R|?v{S1  
return sFilePath; Da<`| l  
} @Mya|zb  
B}7j20:Z  
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public void setSFilePath(String value) 1!zd#TX  
{ F*G]Na@6D  
sFilePath = value; c6b51)sQ"  
} bM'F8Fi  
+184|nJ<2  
n%WjU)<  
public String getSFileName() I?1BGaAA  
{ blomB2vQ  
return sFileName; ce$[H}rDB  
} $JOtUB{  
y:E$n!  
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public void setSFileName(String value) U^}7DJ  
{ ?* +>T@MH  
sFileName = value; |

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} wKJ|;o4;L  
_ow7E\70  
\Ec*Gq?.  
public int getNSplitter() n:a~=^IV  
{ MHp:".1  
return nSplitter; oHfr glGX  
} #)L}{mHLM-  
E\}A<r  
r7R39#  
public void setNSplitter(int nCount) n"?*"Ya  
{ ~|<'@B!6  
nSplitter = nCount; 3ylSO73R  
} ;pL!cG@  
} %V
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/* <0Y<9+g!  
**Utility.java p! k~ufU  
*/ M4|ION  
package NetFox; k^d^Todq.  
qQfNT.  
O:'qwJ#~  
public class Utility { $J<WFDn9  
%$Fe
[#1  
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public Utility() l_;6xkv4  
{ %INkuNa8\  
y<HNAGj  
o;DK]o>kH  
} By9CliOy:  
7'At_oG  
//线程睡眠 EajJv>X7  
public static void sleep(int nSecond) d %FLk=]  
{ HS*Y%*  
try{ (:]+IjnE  
Thread.sleep(nSecond); %*K zP{  
} /:!l&1l:p  
catch(Exception e) 5MYdLAjV  
{ UvU@3[fw  
e.printStackTrace (); T++q.oFc  
} @#^Y# rxb  
} "Uf1;;b  
/V cbT >=  
//日志 Jza?DhSAZ  
public static void log(String sMsg) @+nCNXK  
{ ]H{*Z3S  
System.err.println(sMsg); O46v  
} 0s Jp,4Vv  
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YvuE:ia  
public static void log(int sMsg) V60"j(  
{ [
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System.err.println(sMsg); a;Pn.@NVq  
} '.N}oL<gP  
} CY.92I@S  
S~H>MtX(<  
EUh_`R  
/* x|AND]^Q  
**TestMethod.java .nNZdta&=  
*/ $y.0h(  
package NetFox; #Muh|P]%\  
7;Lv_Y"b  
pUqNB_  
public class TestMethod { g'w"U9tjO  
"1XTgCu\  
)/[L)-~y~  
public TestMethod() XM"Qs.E  
{ ///xx/weblogic60b2_win.exe j[mII5e7g  
try{ |c2sJyj*  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); \ntUxPox.  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); [n&ES\o#(  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 2wPc yD  
fileFetch.start(); \M|:EG%  
} G; exH$y  
catch(Exception e){e.printStackTrace ();} *"Iz)Xzc`  
D vU1+y  
hbr3.<o1lY  
}  y<m[9FC}  
]t&^o**  
\Wg_ gA  
public static void main(String[] args) qQ3pe:n?  
{ 2"shB(:z>  
new TestMethod(); QBi]gT@&g  
} }CZw'fhVWO  
} JC9$"0d7  
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