http断点续传简单实现（java)

/* lfr^NxOU  
**SiteFileFetch.java <KE%|6oER  
*/ K;>9K'n  
package NetFox; jBd=!4n  
import java.io.*;  J2Qt!-  
import java.net.*; h*3{IHAQ  
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public class SiteFileFetch extends Thread { _c(h{dn  
%:OX^^i;  
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SiteInfoBean siteInfoBean = null; //文件信息Bean E*s _Y  
long[] nStartPos; //开始位置 Zt9ld=T  
long[] nEndPos; //结束位置 _!w69>Nj  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 9Q7342  
long nFileLength; //文件长度 Zvr
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boolean bFirst = true; //是否第一次取文件 u EERNo&  
boolean bStop = false; //停止标志 +HgyM0LFg  
File tmpFile; //文件下载的临时信息 ^SM5
oK  
DataOutputStream output; //输出到文件的输出流 {Eqx'j  
*uKYrs [  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） u_FN'p=.  
public SiteFileFetch(SiteInfoBean bean) throws IOException {]dvzoE]  
{ !"'6$"U\K  
siteInfoBean = bean; t oM+Bd:Y  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); RS@G.|  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); :u)Qs#'29  
if(tmpFile.exists ()) YHxQb$v)  
{ qt4%=E;[  
bFirst = false; ,4;'s  
read_nPos(); Mq#Hi9SKY  
} .LbAR u  
else 46B'Ec  
{ Q:'r p  
nStartPos = new long[bean.getNSplitter()]; BH}M]<5  
nEndPos = new long[bean.getNSplitter()]; tGSXTF}G  
} KUUZN  
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} 6 B7F  
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public void run() 64^l/D(  
{ i<q_d7-W'  
//获得文件长度 PI"6d)S2  
//分割文件 h<n2pz}  
//实例FileSplitterFetch kUr/*an  
//启动FileSplitterFetch线程 6]4=8! J  
//等待子线程返回 8m#y>`  
try{ $I<\Yuy-M9  
if(bFirst) %_~1(Glz  
{ {!!8 *ix  
nFileLength = getFileSize(); (`R heEg@f  
if(nFileLength == -1) _x$\E  
{ }FX:sa?5  
System.err.println("File Length is not known!"); .B'ws/%5\  
} m/< @Qw  
else if(nFileLength == -2)  lsgZ  
{ K@{R?j/+  
System.err.println("File is not access!"); xqauSW  
} d ]#`?}  
else [<>%I#7ulG  
{  @l&{ j  
for(int i=0;i<nStartPos.length;i++) :'[ha$  
{ gJg+ ]-h/  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); \tP*Pz  
} NceK>::56  
for(int i=0;i<nEndPos.length-1;i++) n]>L"D,  
{ =c%gV]>G  
nEndPos = nStartPos[i+1]; #RKd>ig%  
} _<l)4A3rS  
nEndPos[nEndPos.length-1] = nFileLength; o WAy[  
} FtDF
}  
} 3FMYs&0r4  
^Cj3\G4,  
|D[LU[<C  
//启动子线程 Or55_E  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; zy|h1.gd  
for(int i=0;i<nStartPos.length;i++) qa4j>;  
{ aY DM)b}  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), =4OV }z=I  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), }C$D-fH8sW  
nStartPos,nEndPos,i); `3z6y&dmx  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ]?NiY:v  
fileSplitterFetch.start(); tg9{(_t/W  
} G'wyH[ d/  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), $J0o%9K   
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); eQMa9_  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", nB}eJD|  
nEndPos = " + nFileLength); PtGFLM9R  
// fileSplitterFetch[nPos.length-1].start(); ke)<E98DC  
~3|)[R=+p1  
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//等待子线程结束 9"}5jq4*  
//int count = 0; o :j'd  
//是否结束while循环 >D_)z/v?"  
boolean breakWhile = false; s%A?B8,  
aPX'CG4m  
=<AG}by![  
while(!bStop) j!@,r^(  
{ `H9!Z$7G  
write_nPos(); F'@9kdp  
Utility.sleep(500); j@4]0o  
breakWhile = true; '>Thn{  
n8FIxl&u  
j{/5i`5m  
for(int i=0;i<nStartPos.length;i++) /!60oV4p0  
{ Q@*9|6-  
if(!fileSplitterFetch.bDownOver) (^]3l%Ed  
{ /PG%Y]l0b  
breakWhile = false; z9v70 q  
break; vOl3utu7  
} 2Tv W 6  
} //bQD>NBO  
if(breakWhile) Fw^^sB  
break; R''2o_F6  
)r(e\_n  
s~c cx"HH  
//count++; %UG|R:  
//if(count>4) 8
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// siteStop(); 3~LNz8Z*  
} G)gb5VW k  
aFL<(,~r  
o<5+v^mt#  
System.err.println("文件下载结束！"); 'L^M"f^I  
} f{|n/j;n=C  
catch(Exception e){e.printStackTrace ();} 'vKae  
} TeyF
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//获得文件长度 T^ #1T$  
public long getFileSize() L:.Rv0XT  
{ {yMkd4v  
int nFileLength = -1; V8Z@y&ny  
try{ ZbH_h]1$D  
URL url = new URL(siteInfoBean.getSSiteURL()); V=Z%y$1Bc  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); iaQFVROu  
httpConnection.setRequestProperty("User-Agent","NetFox"); ^__P;Gr`  
QJI]@3 Y  
:]LW,Eql  
int responseCode=httpConnection.getResponseCode(); HaF&ooI5+  
if(responseCode>=400) !lp7}[k<y  
{ sGa "  
processErrorCode(responseCode); Vq^b_^  
return -2; //-2 represent access is error yP34h*0B  
} /)4Q%Zp  
{&FOa'bP  
@2>c
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String sHeader; BLm}mb#/{  
1\
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.73sY5hdTN  
for(int i=1;;i++) x@x5|8:ga  
{ !"ydl2  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); @}'?o_/C  
//Utility.log(in.readLine()); ~W3t(\B'  
sHeader=httpConnection.getHeaderFieldKey(i); I,r0K]  
if(sHeader!=null) .fK~IKA  
{ 8mO_dQ
 
if(sHeader.equals("Content-Length")) c#@L~<  
{ \t? ;p-+ta  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); r/QI-Cf&  
break; I}awembw g  
} u5`b")a  
} T ^/\Rr  
else qr~zTBT] E  
break; P75@Yu(  
} *~.'lE%[U  
} ~x J#NC+  
catch(IOException e){e.printStackTrace ();} Xod/GYG  
catch(Exception e){e.printStackTrace ();} Q{ {=  
A^4#6],%v  
#.LI`nYA  
Utility.log(nFileLength);
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return nFileLength; "DRiJ.|APs  
} B.);Ju  
-y/Y%]%0  
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//保存下载信息（文件指针位置） Ze?H  
private void write_nPos() }xgs]\^,73  
{ dX-j3lM:#  
try{ FQ/z,it_i  
output = new DataOutputStream(new FileOutputStream(tmpFile)); K'[kl'  
output.writeInt(nStartPos.length); )W1[{?  
for(int i=0;i<nStartPos.length;i++) q%XjJ -s:  
{ @J6V,  
// output.writeLong(nPos); C *7x7|z  
output.writeLong(fileSplitterFetch.nStartPos); cxIAI=JK  
output.writeLong(fileSplitterFetch.nEndPos); $6d5W=u$H  
} K)
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output.close(); oYWHO<b  
} U:|:Y=O?Q  
catch(IOException e){e.printStackTrace ();} =vL >&$  
catch(Exception e){e.printStackTrace ();} yx7y3TSq  
} ]Bz.6OR  
Z/OERO   
V\AF%=6}  
//读取保存的下载信息（文件指针位置） Z0M|Bv9_  
private void read_nPos() fyq%-Tj  
{ 02^Nf
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try{ ;rXZ?"  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); `mquGk|)  
int nCount = input.readInt(); tHFUV\D;,  
nStartPos = new long[nCount]; ;NGSJfn  
nEndPos = new long[nCount]; R-Y 7I  
for(int i=0;i<nStartPos.length;i++) V7k!;0u v  
{ HUel  
nStartPos = input.readLong(); Q@Cy\l  
nEndPos = input.readLong(); d[p?B-7%  
} 1W7ClT_cQ  
input.close(); "_\77cqpTh  
} 9CZEP0i7  
catch(IOException e){e.printStackTrace ();} \WZSY||C|_  
catch(Exception e){e.printStackTrace ();} &B$%|~Y5  
} M2A_T.F=H  
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private void processErrorCode(int nErrorCode)
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{ gbu)bqu2x  
System.err.println("Error Code : " + nErrorCode); Mp@dts/|  
} =ibKdPtTh^  
L; <Pod  
.gCun_td#  
//停止文件下载 hh-sm8  
public void siteStop() |gfG\fL3V  
{ |8akp  
bStop = true; |
  
for(int i=0;i<nStartPos.length;i++) Q%0 N\  
fileSplitterFetch.splitterStop(); \CYKj_c  
&p55Cg@e)  
B06W(y,3Q>  
} 1:q`KkJx  
} VzWH9%w  
//负责部分文件的抓取 )c.!3n/pb  
**FileSplitterFetch.java 2UTmQOm  
*/ -LlS9[r0  
package NetFox; k jx<;##R8  
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< WQ ~X<1D  
import java.io.*; ?p>m;Aq  
import java.net.*; "lB%"}  
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public class FileSplitterFetch extends Thread { zo1fUsK?  
.Z@iz5  
@ b}-<~  
String sURL; //File URL gdg "g6b  
long nStartPos; //File Snippet Start Position p }3$7CR/  
long nEndPos; //File Snippet End Position R^yh,  
int nThreadID; //Thread's ID 43!E>mq  
boolean bDownOver = false; //Downing is over Rvd'uIJ  
boolean bStop = false; //Stop identical (:RYd6i  
FileAccessI fileAccessI = null; //File Access interface L!Gpk)}[i  
nlc$"(eA[H  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException {-hu""x>  
{ Yd<9Y\W%?  
this.sURL = sURL; ~8)l/I=`);  
this.nStartPos = nStart; I-W,C&J>  
this.nEndPos = nEnd; pR!m  
nThreadID = id; |Pv)&'B"  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 j$P`/-N  
} $@~sO0q  
z#6(PZC}  
,]tMZ?n8  
public void run() =RHIB1  
{ l(8@?t^;  
while(nStartPos < nEndPos && !bStop) Xj<xen(  
{ 4@M`BH`  
9dva]$^:*1  
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try{ :,.HJ[Vg&  
URL url = new URL(sURL); vJ>o9:(6  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ((6?b5[  
httpConnection.setRequestProperty("User-Agent","NetFox"); ~e686L0j  
String sProperty = "bytes="+nStartPos+"-"; EU'P U  
httpConnection.setRequestProperty("RANGE",sProperty); `KieN/d%  
Utility.log(sProperty); m~gcc  

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InputStream input = httpConnection.getInputStream(); @u:
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//logResponseHead(httpConnection); &pHXSU  
6|1*gl1_LD  
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byte[] b = new byte[1024]; Tzfk_h3hE  
int nRead; -(zw80@&  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) i({MID)/_  
{ ^$y`Q@-9  
nStartPos += fileAccessI.write(b,0,nRead); P9M%B2DQ6f  
//if(nThreadID == 1) *,,:;F^  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); hcR^?  
} y]
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!14l[k+\  
">q?(i\  
Utility.log("Thread " + nThreadID + " is over!"); .i1|U8"X  
bDownOver = true; 88l{M[B2  
//nPos = fileAccessI.write (b,0,nRead); Qa"4^s  
} "J2v8c  
catch(Exception e){e.printStackTrace ();} A$l  
} }&^1")2t  
} pbGv\SF  
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;7(vqm<V2~  
//打印回应的头信息 wNMA)S  
public void logResponseHead(HttpURLConnection con) vg5fMH9ZZ  
{ e4;h*
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for(int i=1;;i++) Q$Q:Jm53  
{ a@!O}f*  
String header=con.getHeaderFieldKey(i); |wyua@2  
if(header!=null) Ib"fHLWA^!  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); p@wtT"Y  
Utility.log(header+" : "+con.getHeaderField(header)); A%~t[
H  
else "P$')uwE  
break; va!fJ  
} fH%C&xj'&  
} ,W>-MPJn[8  
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public void splitterStop() (Vt5@25JW  
{ %:7/ym[  
bStop = true; jV#1d8qm  
} WPPDvB  
/`7G7pQ+  
J!yK/*sO,  
} M[L@ej  
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5[P^O6'  
/* AH^'E
 
**FileAccess.java 6df`]sc  
*//文件访问(定位，写) WmE4TL^8?  
package NetFox; AA}+37@2I  
import java.io.*; n`p/;D=?  
m[Qr>="  
^CB@4$!   
public class FileAccessI implements Serializable{ X rut[
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. Fm| $x  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 q0@b d2}  
RandomAccessFile oSavedFile; }{.V^;  
long nPos; \# 1p  
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public FileAccessI() throws IOException B XO,  
{ 9/O\769"'  
this("",0); m [BV{25  
} \mw5 ~Rf;  
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public FileAccessI(String sName,long nPos) throws IOException |Rb8/WX  
{ #2%8@?_-M  
oSavedFile = new RandomAccessFile(sName,"rw"); *\^(-p~M  
this.nPos = nPos; gKRlXVS  
oSavedFile.seek(nPos); |j4;XaG)  
} _+ >V(,{G  
_FN#Vq2  
Qi|k,1A0  
public synchronized int write(byte[] b,int nStart,int nLen) y~wN:  
{ ;z~j%L%b  
int n = -1; D+7[2$:z  
try{ gY_AO1  
oSavedFile.write(b,nStart,nLen); kuv+TN  
n = nLen; la`f@~Bbr1  
} vh^?M#\  
catch(IOException e) ,+FiP{`  
{ +aOX{1w  
e.printStackTrace (); 3*oZol/  
} m4G))||9Q  
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4"Mq]_D  
return n; LKst QP!I  
} 'Kd-A:K2g  
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} 8/-hODoT_  
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R  
9\%`/tJM  
/* _]us1  
**SiteInfoBean.java (_fovV=  
*/ aQ0pYk~(  
package NetFox; ?qb
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,6x>gcR  
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public class SiteInfoBean { ~P"o
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l2kUa'O-  
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private String sSiteURL; //Site's URL u3IhB8'  
private String sFilePath; //Saved File's Path "
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private String sFileName; //Saved File's Name LPkl16yZ  
private int nSplitter; //Count of Splited Downloading File |^gnT`+  
MK <\:g  
P5v;o9B&  
public SiteInfoBean() `?SLp  
{//nSplitter的缺省值为5 ]vH:@%3U  
//default value of nSplitter is 5 &,$N|$yK}|  
this("","","",5); ra^"Vr  
} Jl ?_GX}ZY  
^(7Qz&q  
, jCE hb  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) kk}_AZ0eK  
{ A1B%<$|pz  
sSiteURL= sURL; ;G*)7fi  
sFilePath = sPath; ]qiX"<s>~C  
sFileName = sName; F:LrQu  
this.nSplitter = nSpiltter; [$Jsel<T=  
0m4'm<2m  
2Vxx  
} >*$Xbj*  
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vHb^@z=  
public String getSSiteURL() [iC]Wh%  
{ .L.9e#?3  
return sSiteURL; ?B<.d8i  
} Myh?=:1~(c  
f\H1$q\p\  
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public void setSSiteURL(String value) 1eI_F8I U  
{ @su!9]o  
sSiteURL = value; l$m}aQ%h  
} 7hT@,|(j  
NdC5w-WY  
T `o
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public String getSFilePath() ~gg&G~ET  
{ gq~"Z[T  
return sFilePath; =0SJf 3  
} j2mMm/kq\  
Qki
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I 1Yr{(ho  
public void setSFilePath(String value) Nr`v|_U  
{ @IOl0db  
sFilePath = value; i\=I` Yn+  
}  I^G6aw  
@QF;m  
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public String getSFileName() `)TgGny01  
{ $}=r45e0K  
return sFileName; M%7|7V<o)^  
} AsI.8"
 
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6#HnA"I2n  
public void setSFileName(String value) =Ea,8bpn  
{ hz5t/
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sFileName = value; Q<(aU{  
} SME]C')7  
c,#Nd@  
@[{5{ y  
public int getNSplitter() rVp^s/A^;  
{ @?& i   
return nSplitter; (t,mtdD#1  
} :0Fc E,1  
;

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18]Q4s8E  
public void setNSplitter(int nCount) u/FC\xJc  
{ (iht LFp  
nSplitter = nCount; ..=lM:13|  
} 'h[7AZ&)#  
} Mo4c8wp&SM  
@2TfW]6  
n2Q?sV;m  
/* x!u6LDq0  
**Utility.java e1hf{:&/G@  
*/ ,Bj]j -\Y  
package NetFox; vgi`.hk  
.I%B$eH  
f4vdJ5pV  
public class Utility {
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4G RHvA.  
/bmkt@$-0  
public Utility()
UU '9  
{ Y]i:$X]C?X  
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} #hXuGBZEI  
!04^E  
//线程睡眠 }&%&0$%  
public static void sleep(int nSecond) |*L/ m0'L  
{ 845\u&  
try{ (@S9>z4s  
Thread.sleep(nSecond); |I3&a=,  
} ,<[x9 "3\  
catch(Exception e)  JY_!G  
{ %cASk>
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e.printStackTrace (); Bo ??1y  
} a~zh5==QD  
} e'
|c59E  
2hTsjJ!'  
//日志 (A-Uo   
public static void log(String sMsg)  1 K]  
{ kqGydGh*"  
System.err.println(sMsg); !"'@c  
} #q8/=,3EG  
_,w*Rv5=  
FPEab69  
public static void log(int sMsg) Ad4-aWH  
{ ^$<:~qq!  
System.err.println(sMsg); }{v0}-~@  
} 4 &0MB>m  
}
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ZL9|/ PY  
/* ,.&D{$1W  
**TestMethod.java 3w! NTvp  
*/ r$%,k*X^ k  
package NetFox; mOFp!(  
2t7=GA+j  
[ *
!0DW`  
public class TestMethod { f?"909&  
fLV@~T|  
][~rk?YY  
public TestMethod() |^#Z!Hp_Y  
{ ///xx/weblogic60b2_win.exe uNpa2{S'  
try{ EpENhC0  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); B'6(Ao=3/  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 9W j9=  
SiteFileFetch fileFetch = new SiteFileFetch(bean); %t$)sg]  
fileFetch.start(); #:
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} {3 >`k.w  
catch(Exception e){e.printStackTrace ();} ,f
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T? ,Q=.  
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} wL&[Vi_j{  
:BblH0
'  
M$3/jl*#}  
public static void main(String[] args) fg GTm:   
{ )XYCr<s2"  
new TestMethod(); 7s;*vd>  
} $-
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} V
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