http断点续传简单实现（java)

/* vCbqZdy?  
**SiteFileFetch.java N##3k-0Ao  
*/ _h@7>+vl~  
package NetFox; &sJpn*W  
import java.io.*; pVt-7AgW  
import java.net.*; 9S&6u1  
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public class SiteFileFetch extends Thread { F2oY_mA  
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SiteInfoBean siteInfoBean = null; //文件信息Bean cy^6g?ew  
long[] nStartPos; //开始位置 qdZn9i  
long[] nEndPos; //结束位置 4^70r9hV9  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 fgn*3 pg  
long nFileLength; //文件长度 kt X(\Hf!  
boolean bFirst = true; //是否第一次取文件 xE;fM\7pu  
boolean bStop = false; //停止标志 o0s+ roiD  
File tmpFile; //文件下载的临时信息 LL9Mty,  
DataOutputStream output; //输出到文件的输出流 i0p"q p  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） Jev@IORN\  
public SiteFileFetch(SiteInfoBean bean) throws IOException ?@_3B]Fs  
{ 39"8Nq|e  
siteInfoBean = bean; \+Qx}bS{  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); "M_X9n_  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ~O@V;y  
if(tmpFile.exists ()) nm %ka4  
{ Rc?wIL)  
bFirst = false; G*ym[  
read_nPos(); RFg$N@g,  
} nN@8vivP%  
else  `U(A
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{ jh\q2E~,`  
nStartPos = new long[bean.getNSplitter()]; X?4
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nEndPos = new long[bean.getNSplitter()]; SRM[IU  
} _u{D#mmO  
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} lP9a*>=a  
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public void run() 1/a*8vuGh  
{ 1v`<Vb%"}T  
//获得文件长度 _k5KJKvr  
//分割文件 vuDp_p*]S  
//实例FileSplitterFetch ! ~&X1,l1*  
//启动FileSplitterFetch线程 gA~Ih  
//等待子线程返回 quGb;)3  
try{ BR5$;-7W  
if(bFirst) qx0J}6+NlU  
{ 0Lc X7gU>  
nFileLength = getFileSize(); kz,Nz09}W  
if(nFileLength == -1) Ms^Y:,;Hi  
{ .o|Gk 5)  
System.err.println("File Length is not known!"); 2$[u&__E  
} r^*,eF  
else if(nFileLength == -2) xiA9X]FB  
{ .%WbXs  
System.err.println("File is not access!"); x0Tb7y`  
} iKp4@6an  
else bG.aV#$FIg  
{ N1#*~/sXh  
for(int i=0;i<nStartPos.length;i++) <-}6X  
{ wQM(Lm#Q  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 3@ay9!Xq  
} YroKC+4"i  
for(int i=0;i<nEndPos.length-1;i++) zUwz[^d<C  
{ %I6iXq#  
nEndPos = nStartPos[i+1]; )v
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} Qo;$iLt  
nEndPos[nEndPos.length-1] = nFileLength; jew?cnRmd  
} T=b5th}  
} :kY][_  
qr<5z. %  
Bj%{PK  
//启动子线程 Rq4\~F?  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; $ZQPf  
for(int i=0;i<nStartPos.length;i++) #FuOTBNvB  
{ '7xmj:.==  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), s`H}NjWx  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), dxMz!  
nStartPos,nEndPos,i); ~73YOGiGJH  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); '^7Sa  
fileSplitterFetch.start(); ?"qU.}kGL  
} 6wnfAli.  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), /:U\U_j  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); {CQA@p:Y}  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", lQ!6n  
nEndPos = " + nFileLength); !u\X,.h  
// fileSplitterFetch[nPos.length-1].start(); n~K_|  
!y4o^Su[  
-fG;`N5U  
//等待子线程结束 U&`M G1uHe  
//int count = 0; ajkRL|^  
//是否结束while循环 <k<  
boolean breakWhile = false; v C><N  
lv$tp,+  
gfih;i.pY  
while(!bStop) s\>$ K%!H?  
{ ]<z>YyBA  
write_nPos(); #1V vK  
Utility.sleep(500); ,Y9lp)w  
breakWhile = true; 7U?x8%H*  
']}ZI 8  
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for(int i=0;i<nStartPos.length;i++) $+7MY-9T  
{ T-|z18|!  
if(!fileSplitterFetch.bDownOver) Zf?>:P  
{ Pfi '+I`s  
breakWhile = false; AbLOq@lrK  
break; 1{nXmtvr  
} Y}nE/bmx&9  
} eCk}B$ 2  
if(breakWhile) NsWyxcty  
break; iSIj ?.  
g%RL9-z  
";s?#c  
//count++; <K4'|HU/  
//if(count>4) @uT\.W:Q2  
// siteStop(); E(TL+o  
} f&{2G2O%  
sl/#1B  
0QEVL6gw  
System.err.println("文件下载结束！"); U.?,vw'aai  
} 7M^!t X  
catch(Exception e){e.printStackTrace ();} =AZ>2P  
} (y#8z6\dx  
hQ8/-#LO_  
f5d"H6%L  
//获得文件长度 tR0o6s@v/<  
public long getFileSize() \t^q@}~0Wz  
{ ]hv4EL(zi  
int nFileLength = -1; `){*JPl  
try{ ,}`II|.oB  
URL url = new URL(siteInfoBean.getSSiteURL()); Sn
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); (AXSQI~y  
httpConnection.setRequestProperty("User-Agent","NetFox"); 3VALrb;  
m:Z=: -x  
\f@PEiARG7  
int responseCode=httpConnection.getResponseCode(); -i?!em'J  
if(responseCode>=400) SaQ_%-&#p  
{ oACuI|b  
processErrorCode(responseCode); JBi<TDm/  
return -2; //-2 represent access is error 
,$W7Q  
} [^~Fu9+"  
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>8>`-  
String sHeader; +a"Asvw2  
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for(int i=1;;i++) 7(Y!w8q&^  
{ {gK i15t  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); M/R#f9W  
//Utility.log(in.readLine()); X#gZgz ='  
sHeader=httpConnection.getHeaderFieldKey(i); MCL5a@BX)  
if(sHeader!=null) ykX}T6T  
{ ~A [ Ju%R  
if(sHeader.equals("Content-Length")) bWUo(B#*I  
{ c%Kv"Z%f  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Zpl?zI  
break; N;<<-`i  
} T4o}5sq}S  
} ZZzf+F)T  
else }c%QF  
break; waO*CjxE:  
} $>8+t>|  
} fLct!H3  
catch(IOException e){e.printStackTrace ();} f=g/_R2$xN  
catch(Exception e){e.printStackTrace ();} ^<[oKi;>  
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Utility.log(nFileLength); 2+ >.Z.pX  
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return nFileLength; .5KRi6  
} "%-HZw%X  
Xk(c2s&  
 V:F)m!   
//保存下载信息（文件指针位置） IWuR=I$t  
private void write_nPos() VU}UK$JN  
{ Y -
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try{ m:II<tv  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 5JIa?i>B  
output.writeInt(nStartPos.length); VO#]IXaP  
for(int i=0;i<nStartPos.length;i++) K=+w,H#`C  
{ Gvl-q1PVC  
// output.writeLong(nPos); X2q$i  
output.writeLong(fileSplitterFetch.nStartPos); @M:j~  
output.writeLong(fileSplitterFetch.nEndPos); c i_XcG  
} zZ Oo
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output.close(); se2+X>@>  
} )MmMs"Um  
catch(IOException e){e.printStackTrace ();} ^xu`NE8;  
catch(Exception e){e.printStackTrace ();} W&TPrB  
} rsOon2|  
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//读取保存的下载信息（文件指针位置） V,*YM  
private void read_nPos() DJ[U^dWRn  
{ j#3}nJB%#i  
try{ ^HX={(ddK  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); X -w#E3  
int nCount = input.readInt(); \SA5@.W  
nStartPos = new long[nCount]; :7@"EW  
nEndPos = new long[nCount]; |Tf}8e  
for(int i=0;i<nStartPos.length;i++) Yf7n0Etd,  
{ OT{qb!eYI  
nStartPos = input.readLong(); #@3RYx  
nEndPos = input.readLong(); b4S7Q"g  
} ) m%ghpX  
input.close(); v3Te+oLg  
} Hx62x X  
catch(IOException e){e.printStackTrace ();} z!D >l  
catch(Exception e){e.printStackTrace ();} -`&4>\o2Lx  
} ZQsE07  
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private void processErrorCode(int nErrorCode) ^['%wA%  
{ ov*zQP  
System.err.println("Error Code : " + nErrorCode); g@`14U/|  
} DUM,dFIlvF  
>.\G/'\?  
>p}d:t/  
//停止文件下载 o8H<{D13  
public void siteStop() O]4!U#A  
{ 9IN=m 5  
bStop = true; ^qy$M>  
for(int i=0;i<nStartPos.length;i++) M!;H3*  
fileSplitterFetch.splitterStop(); 1Jd82N\'  
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"7l p|0I  
} q'hMf?_  
} *8kg6v%  
//负责部分文件的抓取 hy3[MOD$G  
**FileSplitterFetch.java _+wv3? c"  
*/ 9Rb-QI  
package NetFox; &
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import java.io.*; L7wl3zG  
import java.net.*; =LZj6'  
$_@~t$  
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public class FileSplitterFetch extends Thread { Haaungb"  
<@A/`3_O)  
L!3{ASIN0  
String sURL; //File URL ^qIp+[/'  
long nStartPos; //File Snippet Start Position Op~sR^ez  
long nEndPos; //File Snippet End Position x,5$VLs\+  
int nThreadID; //Thread's ID b+[9)B)a?  
boolean bDownOver = false; //Downing is over />FrMz8;(  
boolean bStop = false; //Stop identical V`pTl3  
FileAccessI fileAccessI = null; //File Access interface *<Fz1~%*  
B[S.6"/H  
~ifq_Ag.  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException &!N5}N&  
{ )[~ #j6  
this.sURL = sURL; \#m;L/D  
this.nStartPos = nStart; g4oFUyk{  
this.nEndPos = nEnd; vD[@cm  
nThreadID = id; *jTr  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 #CW]70H`  
} ~Rs|W;  
9hmCvQgtf  
^G~W}z?-  
public void run() % 95:yyH 0  
{ 3wX{U8mr
g  
while(nStartPos < nEndPos && !bStop) ,B5
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{ 0{BPT>'  
rf@/<Wu  
<{[AG3/Zj4  
try{ dt',)i8D  
URL url = new URL(sURL); one^XYy1%  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); _B8e1an  
httpConnection.setRequestProperty("User-Agent","NetFox"); 2t< dCw  
String sProperty = "bytes="+nStartPos+"-"; f"k?Ix\ e  
httpConnection.setRequestProperty("RANGE",sProperty); lqF{Y<l  
Utility.log(sProperty); o~NeS|a  
l(v$+  
l#\z3"b  
InputStream input = httpConnection.getInputStream(); !6@xX08z  
//logResponseHead(httpConnection); h$f/NSct2  
rPaD#GA[7  
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byte[] b = new byte[1024]; 6mep|![6  
int nRead; bhOyx  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 5y(irbk7  
{ YRG+I GX  
nStartPos += fileAccessI.write(b,0,nRead); ::j'+_9  
//if(nThreadID == 1) bsuUl*l)  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); p87s99  
} T 2x~fiM  
n{r+t=X  
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Utility.log("Thread " + nThreadID + " is over!"); V~Tjz%<  
bDownOver = true; :0CR=]WM  
//nPos = fileAccessI.write (b,0,nRead); R`76Ae`R8  
} d;mQ=k 1  
catch(Exception e){e.printStackTrace ();} p? iJ'K  
} j72cSRv  
} ;wL*  
U"%k4]:A  
pvI(hjMYPk  
//打印回应的头信息 Uf4QQ`c#  
public void logResponseHead(HttpURLConnection con) >u*woNw(XM  
{ d=oOMXYa   
for(int i=1;;i++) I%e7:cs>  
{ JV36@DVQ  
String header=con.getHeaderFieldKey(i); c5;YKON  
if(header!=null) cuq7eMG6z  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Y@9L8XNP>  
Utility.log(header+" : "+con.getHeaderField(header)); TbIM{X  
else ?9H
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break; **_VNDK+  
} |GdA0y\v*}  
} +A~lPXAXW  
@ RTQJ+ms  
Pu/0<Orp7  
public void splitterStop() }td+F&l($V  
{ (pi7TSJ  
bStop = true; {)4Vv`n  
} Mky$#SI11  
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} z6Su`  
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4 3]6J]!)  
/* :e+GtN?  
**FileAccess.java e!tgWYN  
*//文件访问(定位，写) <'P|g  
package NetFox; 1G.+)*:3  
import java.io.*; xBgf)'W_Z  
y^;qT_)#  
o&(%:|  
public class FileAccessI implements Serializable{ )Bb :tz+  
VZAdc*X  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 OUI}jJw+  
RandomAccessFile oSavedFile; ry~3YYEMI0  
long nPos; M8KfC!  
/ sH*if  
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public FileAccessI() throws IOException ~{^A&#P  
{ ei\X/Z*q%P  
this("",0); Ql
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} hZ2PP ^  
7MoO2  
+QldZba  
public FileAccessI(String sName,long nPos) throws IOException =;Wkg4\5  
{ }-r"W7]k  
oSavedFile = new RandomAccessFile(sName,"rw"); D|e6$O5o  
this.nPos = nPos; yA%[u.{  
oSavedFile.seek(nPos); ~@'|R%jJ  
} {/QpEd>3+  
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xZ;';}&pj  
public synchronized int write(byte[] b,int nStart,int nLen) X\1D[n:  
{ ngm7Vs  
int n = -1; * +OAc`8  
try{ XJ?@l3D:  
oSavedFile.write(b,nStart,nLen); +Kf::[wP7  
n = nLen; J,7_5V@jJ  
} a#uJzYB0  
catch(IOException e) _^P>@ ^  
{ 5+ fS$Q  
e.printStackTrace (); Cs
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} 0 |F(qR  
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return n; da I-*  
} t:M>&r:BL  
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fcw\`.
  
} KpwUp5K  
?[m5|ty#  
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/* HnY: gu  
**SiteInfoBean.java
3_33@MM  
*/ X,y$!2QI  
package NetFox; %'g/4I  
/OxF5bN2  
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public class SiteInfoBean { jBE=Ij  
DcOu=Y> 1  
OcSLRN?t  
private String sSiteURL; //Site's URL (
>;~((2  
private String sFilePath; //Saved File's Path \H" (*["&  
private String sFileName; //Saved File's Name IL>g-  
private int nSplitter; //Count of Splited Downloading File YDmFR,047  
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public SiteInfoBean() ||!k 3t#<  
{//nSplitter的缺省值为5 ^8MgNVoJ)  
//default value of nSplitter is 5 |=h>3Z=r!  
this("","","",5); `q xg  
} As)-a5!  
,%,}[q?]d  
bjvi`jyL3k  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) wkIH<w|jb  
{ P}VD}lEyO  
sSiteURL= sURL; DD~8:\QD  
sFilePath = sPath; el[6E0!@  
sFileName = sName; w\@Anwj#L  
this.nSplitter = nSpiltter; ^3r2Q?d\  

z ,ledTl  
a(J~:wgd  
} oa9T3gQ?  
\7/xb{z|  
DAvAozM  
public String getSSiteURL() h[lh01z  
{ E4{^[=}  
return sSiteURL; 9JUlu  
} wiFckF/  
3gGF?
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|bBYJ  
public void setSSiteURL(String value) TnKe"TA|9  
{ ;e[-t/SI  
sSiteURL = value; TI*uNS;-  
} M@gm.)d  
a]ftE\99  
8<g5.$xyz  
public String getSFilePath() Nz]\%c/-  
{ ( E0be.  
return sFilePath; =UYc~VUYnT  
} 0<P -`|X  
,m:MI/)p  
4~Z\tP|Q.  
public void setSFilePath(String value) a"ht\v}1  
{ Z-/

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sFilePath = value; /[us;=CM  
} $MP'j9-S?  
3N<FG.6  
&1VC0"YJWy  
public String getSFileName() >Vg<J~[
g  
{ ^WVr@6  
return sFileName; |#MA?oz3T  
} JM!o(zbt  
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yCmiW %L4  
public void setSFileName(String value) X#pE!mT  
{ OP>'<FK  
sFileName = value; fwOvlD&e  
} m"xw5aa>  
Z$+0gm\Cnw  
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public int getNSplitter() N]5-#  
{ !rwv~9I  
return nSplitter; 0P!6 .-XU  
} QRa>W/N  
!qy/'v4  
)WBTqML[  
public void setNSplitter(int nCount) :.Np7[~{  
{ 'KXvn0
 
nSplitter = nCount; tTP"*Bb  
} CM~)\prks  
} 0A|.ch  
f4:gD*YT  
/tV)8pEj  
/* zs7K :OlkA  
**Utility.java zQD$+q5h  
*/ xy[R9_V  
package NetFox; #,$d!l @  
jtN2%w;  
RELLQpz3  
public class Utility { 8wwD\1pLS  
/(XtNtO*  
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public Utility() iGm[fxQ|  
{ L%N|8P[  
\/'u(|G  
mO]>(^c  
} h*&-[nSo  
lB3W|-Ci  
//线程睡眠 LiiQ;x  
public static void sleep(int nSecond) 347p2sK>  
{ #uFP eu:  
try{ jsc1B  
Thread.sleep(nSecond); De\&r~bTW9  
} Ll%[}C?~]?  
catch(Exception e) hQPiGIs
  
{ Xk
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e.printStackTrace (); d\D.l^  
} ^q7 fN0"6  
} \h?C G_|]  
yw$er?  
//日志
}M * Oo  
public static void log(String sMsg) wjQu3 ,Cj  
{ hH|3s-o  
System.err.println(sMsg); 9UZKL@KC  
} jL>IX`,+6  
MAQkk%6[g  
E"nIC,VZ  
public static void log(int sMsg) `(.K|l}  
{ PiP\T.XANa  
System.err.println(sMsg); y2yW91B,  
} OT&J OTk\  
} hK&jo(V  
DH
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C/\)-^  
/* iE!\)7y  
**TestMethod.java -:dUD1  
*/
^
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package NetFox; w:#yu  
5_x8!v  
6`+dP"@  
public class TestMethod { 1c8J yp  
V^As@P8,'(  
5O%Q*\(  
public TestMethod() 6DD"Asi+  
{ ///xx/weblogic60b2_win.exe nM>oG'm[n  
try{ :]v%6i.  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); sjvlnnO  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ]ECzb/  
SiteFileFetch fileFetch = new SiteFileFetch(bean); @~qlSU&  
fileFetch.start(); u`O
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} P=OHiG\z  
catch(Exception e){e.printStackTrace ();} DKx8<yEky  
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=rMT1  
} nm_]2z O  
$0~H~-  
s
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public static void main(String[] args) ?4P*,c  
{ uckag/tv  
new TestMethod(); yF8 av=<{  
} K*xqQ]&  
} LJt#c+]Li  
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