http断点续传简单实现（java)

/* zd[k|lj  
**SiteFileFetch.java F- -g?Q^  
*/ rp4D_80q  
package NetFox; R0qZxoo  
import java.io.*; C$[iduS  
import java.net.*; $0 .6No_|  
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public class SiteFileFetch extends Thread { OdFF)-K>~  
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SiteInfoBean siteInfoBean = null; //文件信息Bean LL e*|:  
long[] nStartPos; //开始位置 GM2}]9  
long[] nEndPos; //结束位置 )zxb]Pg+  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 L(y
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long nFileLength; //文件长度 MAYb.>X#>  
boolean bFirst = true; //是否第一次取文件 8n5~K.;<  
boolean bStop = false; //停止标志 R:f!ywj%  
File tmpFile; //文件下载的临时信息 <XLaJ;j  
DataOutputStream output; //输出到文件的输出流 d0)]^4HT|y  
?+.mP]d_  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） #A5X,-4G  
public SiteFileFetch(SiteInfoBean bean) throws IOException J>v[5FX+  
{ Md~SzrU  
siteInfoBean = bean; aM $2lR])J  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ')v,<{  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); +UDt2  
if(tmpFile.exists ()) {`D]%e
RO  
{ ~Y`ys[Z m  
bFirst = false; Ibz9juY  
read_nPos(); yo[Sh6r/9b  
} |^-D&C(Eu  
else 7nT|yL?  
{ Nqj@p<y/q  
nStartPos = new long[bean.getNSplitter()]; &j:e<{@  
nEndPos = new long[bean.getNSplitter()]; :O413#8  
} Pp }Z"  
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} B/l^=u+-  
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public void run() dI\_I]  
{ _+48(QF<  
//获得文件长度 ;J|t-$Z  
//分割文件 Az@@+?,%Y  
//实例FileSplitterFetch X[$h &]  
//启动FileSplitterFetch线程 he~8V.$  
//等待子线程返回 $\ZWQct  
try{ fJ8>nOh  
if(bFirst) Q`*U U82!  
{ <5G(Y#s/?  
nFileLength = getFileSize(); )f$4:Pq  
if(nFileLength == -1) L6CI9C;-b  
{ bIGcszWr  
System.err.println("File Length is not known!"); -m}'I8  
} [RKk-8I  
else if(nFileLength == -2) ufk2zL8y  
{ = vqJ0!  
System.err.println("File is not access!"); b4L7]&  
} !AXLoq$SY  
else >0@w"aKn  
{ R|*0_!O:[  
for(int i=0;i<nStartPos.length;i++) CtMqE+j^  
{
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); {v
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} ]D;*2Lw4&  
for(int i=0;i<nEndPos.length-1;i++) d(|?gN^  
{ h rSH)LbJ  
nEndPos = nStartPos[i+1]; J\@g3
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} B{=DnB6  
nEndPos[nEndPos.length-1] = nFileLength; SWw!s&lP&  
} J.JD8o9sa  
} 'a0M.*f}G  
,iYhD-"'  
>rlUV"8jY;  
//启动子线程 ynw(wSH=  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; =)Hu
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for(int i=0;i<nStartPos.length;i++) nam]eW  
{ Jw5@#
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fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), oo;<I_#07  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), \bT0\ (Js\  
nStartPos,nEndPos,i); }*bp4<|  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); EeMKo  
fileSplitterFetch.start(); =7e!'cF[  
} Ze>R@rK  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), P Ptmh. }e  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); |a03SZx  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", +JYb)rn$^  
nEndPos = " + nFileLength); t
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// fileSplitterFetch[nPos.length-1].start(); "y~*1kBu  
Iq%<E:+GL  
Vj4 h#NN$  
//等待子线程结束 564L.^$@|  
//int count = 0; />E ILPPb  
//是否结束while循环 q`PA~C];  
boolean breakWhile = false; _w\i~To!  
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7yu-xnt3s  
while(!bStop) B?&0NpVD  
{ W#!AZ!  
write_nPos(); WYF8?1dt +  
Utility.sleep(500); FR6 W-L  
breakWhile = true; 6IRRRtO(  
p#qla'  
MS#"TG/)  
for(int i=0;i<nStartPos.length;i++) A-1KTD  
{ z&0[F`U  
if(!fileSplitterFetch.bDownOver) &Ih}"  
{ <_8bAO8\  
breakWhile = false; )SP"V~^Wn  
break; 'y!qrmMRr  
} 5|0/$ SWd*  
} 6p  }a!  
if(breakWhile) +x

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break; >}f!. i  
o]tfvGvU*  
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//count++; vTFG*\Cq  
//if(count>4) ##''d||u  
// siteStop(); ZRYlm$C  
} YGPb8!  
Zgh~7Z/  
" 4#&tNQ  
System.err.println("文件下载结束！"); .n+ ;&5  
} w=?nD6Xhz  
catch(Exception e){e.printStackTrace ();} kwaZn~  
} 3|w$gG;Y  
Z[VrRT,\c  
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//获得文件长度 I}u\ov_Su  
public long getFileSize() 0`.&U^dG  
{ |WS@q'
  
int nFileLength = -1; i 1w]j  
try{ evZP*N~G  
URL url = new URL(siteInfoBean.getSSiteURL()); p#w8$Qjp  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); u
9Adu`  
httpConnection.setRequestProperty("User-Agent","NetFox"); B&B4 P  
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zjA#8;h~w  
int responseCode=httpConnection.getResponseCode(); e8f7*S8  
if(responseCode>=400) DjaXJ?'  
{ pjS##pgVq  
processErrorCode(responseCode); n;. M5}O  
return -2; //-2 represent access is error Q3& ?28  
} H(K!{k  
%CnVK1u!  
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String sHeader; `D=OEc  
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for(int i=1;;i++) \i[N";K  
{ CR.d3!&28  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 3/usgw1  
//Utility.log(in.readLine()); a0]GQyIG  
sHeader=httpConnection.getHeaderFieldKey(i); wQ+il6  
if(sHeader!=null) 837:;<T  
{ @i'D)6sC  
if(sHeader.equals("Content-Length")) tk-)N+M.  
{ GIYdI#0RC  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); !wE% <Fh  
break; >pZ_  
} "LDNkw'  
} L'$\[~Ug  
else yj'lHC  
break; > .}G[C  
} X} V]3  
} ~0024B[G  
catch(IOException e){e.printStackTrace ();} Q'cWqr  
catch(Exception e){e.printStackTrace ();} x])j]k  
GGwwdB\x'  
Yur}<>`(  
Utility.log(nFileLength); D@sMCR  
n%\\1  
K!(WcoA&2i  
return nFileLength; C$q-WoTM(  
} a}` M[%d7  
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fA?Wf[`x  
//保存下载信息（文件指针位置） 4MDVR/Z7  
private void write_nPos() 'HfI~wN  
{ :T PG~`k(  
try{ SF:{
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output = new DataOutputStream(new FileOutputStream(tmpFile)); w<!&%  
output.writeInt(nStartPos.length); SkipP
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for(int i=0;i<nStartPos.length;i++) cEp/qzAiD%  
{ g3vbskY|  
// output.writeLong(nPos); ,1|=_M31  
output.writeLong(fileSplitterFetch.nStartPos); i)cG  
output.writeLong(fileSplitterFetch.nEndPos); 7o+VhW<|5  
} 3Jda:  
output.close(); &q4~WRnzJk  
} H/W&a2R^P  
catch(IOException e){e.printStackTrace ();} ~FI} [6Dd  
catch(Exception e){e.printStackTrace ();} 8KP  
} uCW}q.@4  
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//读取保存的下载信息（文件指针位置） ?vD<_5K;I  
private void read_nPos() d_:tiHw$  
{ *a_QuEw_k  
try{ _u_|U  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ZA_~o#0%  
int nCount = input.readInt(); p+Bvfn  
nStartPos = new long[nCount]; tIBEja^l  
nEndPos = new long[nCount]; {hO|{vz  
for(int i=0;i<nStartPos.length;i++) Y8s-cc(  
{ @:'E9J06  
nStartPos = input.readLong(); 26_PFHQu4  
nEndPos = input.readLong(); ;$!0pxL)s  
} MD1d  
input.close(); <;+QK=f  
}
P:'y}a-  
catch(IOException e){e.printStackTrace ();} <;b  
catch(Exception e){e.printStackTrace ();} 7~MWp4.  
} ByWad@-6i  
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;F,6]LH!  
private void processErrorCode(int nErrorCode) -jTK3&5  
{ >i1wB!gc8  
System.err.println("Error Code : " + nErrorCode); A}pe>ja  
}  q_;#EV  
8BS$6Pa  
:/Y4I)'  
//停止文件下载 =5pwNi_S  
public void siteStop() )d {8Cu6  
{ Y'6P ~C;v  
bStop = true; 1U~'8=-  
for(int i=0;i<nStartPos.length;i++) ;rCCkA6  
fileSplitterFetch.splitterStop(); V^9%+L+E5  
~te{9/   
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} ~fgS"F^7n  
} ,tBc%&.f  
//负责部分文件的抓取 +x:VIi  
**FileSplitterFetch.java k8.,id  
*/ OnW,R3eg  
package NetFox; 5oD%~Fk l  
P!~&Ei  
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import java.io.*; giddM2'  
import java.net.*; OJcI0(G  
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public class FileSplitterFetch extends Thread { ON_GD"  
]=0D~3o3  
+w3k_^X9c  
String sURL; //File URL x4_FG{AIu  
long nStartPos; //File Snippet Start Position 7 Uu  
long nEndPos; //File Snippet End Position 9JC8OSjJ  
int nThreadID; //Thread's ID !.{{QwZ  
boolean bDownOver = false; //Downing is over i6h0_q
8 >  
boolean bStop = false; //Stop identical CBx5:}t  
FileAccessI fileAccessI = null; //File Access interface |-AR)Smt  
c*>SZ'T\  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 6^p>f:5  
{ v".u#G'u  
this.sURL = sURL; n-lDE}K9%B  
this.nStartPos = nStart; $J:~jY/J  
this.nEndPos = nEnd; w\.z-6G  
nThreadID = id; <J1$s_^`  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 !3at(+4  
} Lr(wS {  
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public void run() Zf`ddT  
{ j~9,Ct  
while(nStartPos < nEndPos && !bStop) QNm.8c$  
{ Zo(QU5m0  
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try{ ;,_c1x/F  
URL url = new URL(sURL); ?jBh=X\]:  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); POUD*(DqNK  
httpConnection.setRequestProperty("User-Agent","NetFox"); 9o5_QnGE  
String sProperty = "bytes="+nStartPos+"-"; y {1p#  
httpConnection.setRequestProperty("RANGE",sProperty); nxYp9,c"  
Utility.log(sProperty); $3n@2 N`  
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InputStream input = httpConnection.getInputStream(); ?r6uEZ  
//logResponseHead(httpConnection);
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ze%)fZI0f  
b<rJ@1qtJ  
byte[] b = new byte[1024]; _52BIrAO2  
int nRead; W%7m3/d  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) u
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{ h|'T'l&z  
nStartPos += fileAccessI.write(b,0,nRead); d~J4&w  
//if(nThreadID == 1) wms8z  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); U5wO;MA  
} 'xp&)gL  
Q|}Pc>ae  
[I` 6F6  
Utility.log("Thread " + nThreadID + " is over!"); lN^} qg><  
bDownOver = true; #(NkbJ5ka  
//nPos = fileAccessI.write (b,0,nRead); BK:S:  
} _-I0f##.  
catch(Exception e){e.printStackTrace ();} 3F0:v,+;  
} y/@.T\p  
} I806I@ix  
a<X<hxW:  
^^Tu/YC9x  
//打印回应的头信息 pb5'5X+  
public void logResponseHead(HttpURLConnection con)  Dy@f21+  
{ *m sW4|=^2  
for(int i=1;;i++) D~Y3\KP  
{ xem:#>&r  
String header=con.getHeaderFieldKey(i); bP 2IX  
if(header!=null) "i1~YE  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); >m{)shBX  
Utility.log(header+" : "+con.getHeaderField(header));  HRKe 7#e  
else 3E361?ubM  
break; Z*|qbu)  
} v2Bks2  
} r'q9N  
,2%>e"%  
)rs);Pl  
public void splitterStop() S|%f<zAtJ  
{ "syf@[tz7  
bStop = true; /\KB*dX  
} MW+]w~7_Q  
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} lLT;V2=osX  
m+Yj"RMx&  
g.N~81A
 
/* \TrhJ  
**FileAccess.java ~WJEH#  
*//文件访问(定位，写) B/Lx,

 
package NetFox; _6 ~/`_(KP  
import java.io.*; (k..ll p~  
J,E'F!{  
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public class FileAccessI implements Serializable{ d\V\,%&.  
PU^Z7T);  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 s!2pOH!u
 
RandomAccessFile oSavedFile; h30~2]hH  
long nPos; ds4)Nk4%O  
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08S|$_  
public FileAccessI() throws IOException f[!QR  
{ @&]j[if(s  
this("",0); C/+8lA6NV  
} #IP<4"Hf  
W<3nF5!  
3L4lk8Dd  
public FileAccessI(String sName,long nPos) throws IOException #{l+I(M  
{ ?'h<yxu]u0  
oSavedFile = new RandomAccessFile(sName,"rw"); qf9.S)H1Z  
this.nPos = nPos; #]|9aVrr  
oSavedFile.seek(nPos); dQt*/]{q  
} d*T;RBk  
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public synchronized int write(byte[] b,int nStart,int nLen) /9WR>NUAO  
{ *IGgbg[0  
int n = -1; n5%rsNxg  
try{ eGblQGRS  
oSavedFile.write(b,nStart,nLen); SN'LUwaMp!  
n = nLen; 2`l$uEI3oJ  
} F#Oqa^$(  
catch(IOException e) Eq.?Ga  
{ '@Y@H
,  
e.printStackTrace (); 5_nkN`x  
} b'^-$  
UPPDs"  
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return n; Sj}@5 X6 C  
} y^:g"|q  
>'8.>f  
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}  OXzJ%&h  
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1z$;>+g<  
/* >0SF79-RE  
**SiteInfoBean.java w'.ny<Pe  
*/ Vl?R?K=`~J  
package NetFox; OlFls 8#>  
7+j@0v\  
'd1E~A  
public class SiteInfoBean { #Qy*zU#9  
s%J|r{F6  
abCcZ<=|b  
private String sSiteURL; //Site's URL aIZ@5w"7  
private String sFilePath; //Saved File's Path z8= Gc$w!  
private String sFileName; //Saved File's Name >OwVNG  
private int nSplitter; //Count of Splited Downloading File cu|#AW  
r+>E`GGQ  
KC?hsID{  
public SiteInfoBean() [cru+c+O:  
{//nSplitter的缺省值为5 E'&UWDh  
//default value of nSplitter is 5 7##nY3",^  
this("","","",5); ^`\c;!)F<  
} IX^k<Jqr  
z(3mhMJY  
yGH'|`  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ZqkP# ]+Y'  
{ ?G
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sSiteURL= sURL; 3b{8c8N^  
sFilePath = sPath; &H,j .~a&l  
sFileName = sName; Hv<%_t_/  
this.nSplitter = nSpiltter; l8%x(N4  
M{:gc7%  
,ibI@8;#~'  
} x"v5'EpL  
-(qoz8H5  
b2H!{a"  
public String getSSiteURL() jfS?#;T)  
{ i,FG?\x@  
return sSiteURL; hX 9.%-@sR  
} 0:h;ots'  
RoLUPy9U  
]^&DEj{  
public void setSSiteURL(String value) McxJ C<  
{ _W]2~9  
sSiteURL = value; .?_wcp=  
} N*lq)@smq  
#2I[F  
(OYR, [*  
public String getSFilePath() vP3Fb;  
{ <=cj)  
return sFilePath; 3>0/WbA:7E  
} Xe*@`&nv@  
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-t?S:9[w  
public void setSFilePath(String value) g;\zD_":l  
{ e&7GW9FSg  
sFilePath = value; x7l)i!/$  
} /!JpmI  
JQsS=m7Et  
o]MQ)\r  
public String getSFileName() }%y_LcL  
{ xh@H@Q\  
return sFileName; t_3)}  
} zScV 9,H1  
h^~eTi;c]Q  
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public void setSFileName(String value) A,lcR:@w  
{ ePIBg(  
sFileName = value; KHcfP7  
} ^P:9iu)+]~  
`\q4z-<-  
j"_V+)SD  
public int getNSplitter() . ~G>vVb  
{ h}z^NX  
return nSplitter; 1<<`T%&  
} jLD=EJ  
d~S.PRg=  
-C
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public void setNSplitter(int nCount) o,D>7|h  
{ {^"c>'R  
nSplitter = nCount; }N2T/U  
} nrwb6wj  
} X LA  
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6peO9]Zy  
/* JF%+T yMe  
**Utility.java u~1[nH:  
*/ 2y ~]Uo  
package NetFox; eAu3,qoM  

q'3=  
*FK!^
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public class Utility { Z?XE~6aP>  
vj[ .`fY  
$62ospR^Y  
public Utility() 9j:?s;B  
{ GZXUB0W\@)  
l K}('7\  
L;fhJ~r  
} O#Xq0o  
I#Iu:,OT  
//线程睡眠 7,j}]  
public static void sleep(int nSecond) 1reJ7b0  
{ ut& RKr3  
try{ +S^Uw'L$=T  
Thread.sleep(nSecond); a`q">T%q  
} cEve70MV  
catch(Exception e) h+,zfVJu  
{ 2B=yT8  
e.printStackTrace (); [% |i  
}  Cj_cu  
} UR1U; k  
7AV!v`  
//日志 u{ JAC!  
public static void log(String sMsg) ud'r?QDM  
{ f/*Xw{s#  
System.err.println(sMsg); _D$|lk-  
} Ga.a"\F.V  
}4#%0x`w  
!j%v
Ue;t  
public static void log(int sMsg) @,i:fY  
{ MHI0>QsI  
System.err.println(sMsg); ~BrERUk  
} c/x ^I{b*  
} t$]lK6  
|M)'@s:  
BtVuI5*h  
/* 'r(}7>~fC  
**TestMethod.java -XkCbxZ  
*/ !RFl
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package NetFox; ,K+K`"Oy  
(/v(.t  
9{'GrL  
public class TestMethod { Jq<&`6hn  
Ad9'q!_en  
J6n@|L!yO  
public TestMethod() (](:0H  
{ ///xx/weblogic60b2_win.exe ,m8l /wG  
try{ xs.>+(@|;  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Br`Xw^S  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); < :<E~anH  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 9Fv1D  
fileFetch.start(); XBF#ILJ  
} owmV7E
1  
catch(Exception e){e.printStackTrace ();} |@sUN:G4k  
CS:j->  
k9.@S  
} vCFMO3  
^UEI`_HO0  
t}c ymX
~  
public static void main(String[] args) BCJo/m  
{ QuT8(s1Q!  
new TestMethod(); (Z,v)TOXjV  
} PUuxKW}  
} k_ UY^vz.  
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