http断点续传简单实现（java)

/* h: yJ  
**SiteFileFetch.java [~Ky{:@)[  
*/ s[GHDQ;!  
package NetFox; ZtZ3I?%U3  
import java.io.*; lEl.'X$  
import java.net.*; _1[Wv?  
A~xw:[zy$a  
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public class SiteFileFetch extends Thread { gaN/ kp  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ]Ea-MeH  
long[] nStartPos; //开始位置 JDf>Qg{  
long[] nEndPos; //结束位置 7:B/?E  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 xHt7/8wF  
long nFileLength; //文件长度 4Q!A w  
boolean bFirst = true; //是否第一次取文件 m 3UK`~ji  
boolean bStop = false; //停止标志 \k5"&]I3  
File tmpFile; //文件下载的临时信息 {9(0s| pr  
DataOutputStream output; //输出到文件的输出流 Ma!  
7;+G
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） %GTFub0F  
public SiteFileFetch(SiteInfoBean bean) throws IOException R?u(aY)P  
{
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siteInfoBean = bean; %Bw:6Y4LZ  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 'IY?=#xr'`  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); \ Bj{.
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if(tmpFile.exists ()) &]YyV.
 
{ Ck#e54gJX  
bFirst = false; T1q27I  
read_nPos(); # bHkI~  
} %16Lo<DPm  
else WOZuFS13  
{ ,c"J[$i$  
nStartPos = new long[bean.getNSplitter()]; VwH|ed$  
nEndPos = new long[bean.getNSplitter()]; {C&Uq#V  
} 1UK= t  
"dP-e  

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} ]y.V#,6e  
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public void run() #f"eZAQ {  
{ z'l HL  
//获得文件长度 ~;9n6U  
//分割文件 |K_%]1*riC  
//实例FileSplitterFetch -+{[.U<1jk  
//启动FileSplitterFetch线程 uGz)Vz&3  
//等待子线程返回 4GP?t4][  
try{ sJKr%2nVV  
if(bFirst) V?dwTc  
{ !`%j#bv  
nFileLength = getFileSize(); XA<h,ONE?  
if(nFileLength == -1) oi|N8a2R  
{ 5IUdA?  
System.err.println("File Length is not known!"); "x R6~8  
} }$z(?b  
else if(nFileLength == -2) Eu' ;f_s  
{ nQQHm6N
 
System.err.println("File is not access!"); .mfLHN%:  
} wxqX42v  
else mDK*LL5]W  
{ y>}r  
for(int i=0;i<nStartPos.length;i++) h&K$(}X  
{ nHm29{G0  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); l6#Y}<tq  
} _%R^8FjH*  
for(int i=0;i<nEndPos.length-1;i++) 7)QZ<fme  
{ Xuu&`U~%  
nEndPos = nStartPos[i+1]; ..5~x~O  
} ,z.l#hj,{  
nEndPos[nEndPos.length-1] = nFileLength; 2Snb+,o2  
} .KKecdd?=  
} r QiRhp  
Dx1(}D  
x)=l4A\  
//启动子线程 ?
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; n4!RGq.}  
for(int i=0;i<nStartPos.length;i++) .i
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{ !.,J;Qt  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), M>Q ZN  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), %d];h  
nStartPos,nEndPos,i); d7](fw@c  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ["f6Ern  
fileSplitterFetch.start(); 27fLW&b2  
} =V|jd'iwx  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), <&Xl b0  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); )Xg5=zn$  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", UH-873AK  
nEndPos = " + nFileLength); rmzzbLTu  
// fileSplitterFetch[nPos.length-1].start(); H2%Qu<Kg2  
dJ I }uQ  
OY}FtGy  
//等待子线程结束 C0[U}Y/r2  
//int count = 0; <4.Exha;=  
//是否结束while循环 !DOyOTR&3  
boolean breakWhile = false; by'KJxl[  
beo(7,=&  
h_?`ESI~  
while(!bStop) >I\B_q  
{ Q&.uL}R  
write_nPos(); 0&sa#g2  
Utility.sleep(500); %?+vtX  
breakWhile = true; +ZNOvcsV  
H;4QuB'^  
,B'=$PO%  
for(int i=0;i<nStartPos.length;i++) =tD*,2]  
{ nfF$h}<o+  
if(!fileSplitterFetch.bDownOver) \4wMv[;7  
{ #dae^UjM  
breakWhile = false; 0#OyT'~V%  
break; <~
5O-.G]  
} F:q4cfL6  
} AwNr}9`  
if(breakWhile) "W"^0To  
break; vcd
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" Bx@(  
9{OO'at?  
//count++; 6Yn>9llo}=  
//if(count>4) (*$F7oO<  
// siteStop(); 2pdeJ  
} FShjUl>m
V  
I;NW!"pU  
Ur#jJR@%3  
System.err.println("文件下载结束！"); +Mq\3  
} QO}~"lMj  
catch(Exception e){e.printStackTrace ();} SM8N*WdiU  
} zEFS\nP}E  
,e43m=Kh
K  
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//获得文件长度 $6mShp9(  
public long getFileSize() QUW`Yc  
{ r\Y,*e  
int nFileLength = -1; =F$?`q`  
try{ pgES)  
URL url = new URL(siteInfoBean.getSSiteURL()); O8.xt|  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 7 2JwG7qh  
httpConnection.setRequestProperty("User-Agent","NetFox"); I}bu  
`B@eeXa;u  
FzX ;~CA  
int responseCode=httpConnection.getResponseCode(); ?pZU'5le`  
if(responseCode>=400) 5zBA]1PY  
{ LH(P<k&  
processErrorCode(responseCode);  Kg';[G\  
return -2; //-2 represent access is error l%2VA  
} K
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7FoX)54"  
Oq~{HJ{  
String sHeader; Qw2`@P8W  
Gw3+TvwU+Q  
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for(int i=1;;i++) S'34](9n6  
{ GKIzU^f  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); n7bVL#Sq[  
//Utility.log(in.readLine()); 9JP:wE~y  
sHeader=httpConnection.getHeaderFieldKey(i); X1(ds*'Kv  
if(sHeader!=null) `15}jTi  
{ e#Ao]gc  
if(sHeader.equals("Content-Length")) }{N#JTmjB#  
{ 'O)v@p "  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); <@(\z   
break; >u> E !5O  
} b
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} :bct+J}l~  
else O80Z7  
break; B
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} OU%"dmSDk  
} g/.FJ-I*  
catch(IOException e){e.printStackTrace ();} M}o.= Iqa  
catch(Exception e){e.printStackTrace ();} zN
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Utility.log(nFileLength); 2x<BU3  
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return nFileLength; n
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}  Culv/  
>P j#?j*Y  
|_p7vl"  
//保存下载信息（文件指针位置） T3oFgzoO  
private void write_nPos() e=VSO!(rY  
{ y`zdI_!7  
try{ u W,J5!  
output = new DataOutputStream(new FileOutputStream(tmpFile)); e*T^:2oRl  
output.writeInt(nStartPos.length); aQmS'{d?^  
for(int i=0;i<nStartPos.length;i++) CrI<rD%'  
{ &'12,'8  
// output.writeLong(nPos); }Q:
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output.writeLong(fileSplitterFetch.nStartPos); wqDf\k}'v  
output.writeLong(fileSplitterFetch.nEndPos); VQ('ejv}/  
} 3y.+03 W  
output.close(); k?7"r4Vc)S  
} =Ya^PAj '}  
catch(IOException e){e.printStackTrace ();} w&H>`l06  
catch(Exception e){e.printStackTrace ();} NE#`ZUr3  
} WVyDE1K<  
uB
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.>;??BG}  
//读取保存的下载信息（文件指针位置） <!
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private void read_nPos() <7`k[~)VB  
{ O<p=&=TD7  
try{ bJMsB|r  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); t }4  
int nCount = input.readInt(); b)IQa,enH  
nStartPos = new long[nCount]; 8g8eY pG  
nEndPos = new long[nCount]; %TI3Eb  
for(int i=0;i<nStartPos.length;i++) jX4$PfOhR  
{ ^!^M Gzu  
nStartPos = input.readLong(); -sv%A7i  
nEndPos = input.readLong(); r
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} Caj H;K\  
input.close(); !4cCq_  
} &<*M{GW'&  
catch(IOException e){e.printStackTrace ();} .^A4w;jPU  
catch(Exception e){e.printStackTrace ();} D,..gsg  
} ^/?7hbr  
|s/Kb]t  
r(wf>w3  
private void processErrorCode(int nErrorCode) 40=u/\/K  
{ 4
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System.err.println("Error Code : " + nErrorCode); )kjQ W&)g  
} w|G7h=  
fPTLPcPP  
TqN@l\  
//停止文件下载 v @M6D}  
public void siteStop() }~LGq.H  
{ On O_7'4 t  
bStop = true; >.UEs8Q
V  
for(int i=0;i<nStartPos.length;i++) DW,ERQ^  
fileSplitterFetch.splitterStop(); {w3<dfJ  
J;XO1}9  
kJB:=iq/x$  
} .7 j#F  
} uDG>m7(}/h  
//负责部分文件的抓取 Fp?M@  
**FileSplitterFetch.java #@YKNS[  
*/ Ge=6l0  
package NetFox; U4dfO=  
*?Wz/OJ0  
MjQ>&fUK  
import java.io.*; 6miXaAA8  
import java.net.*; xr.;B`T0\'  
:KC]1_zqR  
x Y$x=)  
public class FileSplitterFetch extends Thread { 5hEA/G  
,^ ,R .T  
m~=VUhPd  
String sURL; //File URL B7qi|Fw  
long nStartPos; //File Snippet Start Position 1Bs t|  
long nEndPos; //File Snippet End Position j/oc+ M^  
int nThreadID; //Thread's ID rg[#(  
boolean bDownOver = false; //Downing is over +Goh`!$Rj9  
boolean bStop = false; //Stop identical |#t^D.j  
FileAccessI fileAccessI = null; //File Access interface !ckluj  
4J'0k<5S  
eI`%J3BxR  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException \5N\NN @J  
{ bhDqRM  
this.sURL = sURL; KRm)|bgE  
this.nStartPos = nStart; 9qi|)!!L  
this.nEndPos = nEnd; 07qjWo/t  
nThreadID = id; o:UNSr  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 )RFY2}  
} %! S
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GZ5DI+3  
4VF]tX?o  
public void run() ci?\W6  
{ Z
! /_H($  
while(nStartPos < nEndPos && !bStop) Yt_tAm  
{ 6&i])iH  
?gAwMP(>  
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try{ k=d_{2 ~  
URL url = new URL(sURL); sw1gpkX  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); &)q>Z!C-l  
httpConnection.setRequestProperty("User-Agent","NetFox"); $&, KZ>  
String sProperty = "bytes="+nStartPos+"-"; <a
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httpConnection.setRequestProperty("RANGE",sProperty); , DuyPBAms  
Utility.log(sProperty); W4qT]m  
F{ 4k2Izr  
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InputStream input = httpConnection.getInputStream(); ulg=,+%r  
//logResponseHead(httpConnection); yN[i6oe  
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YJz06E1 -9  
byte[] b = new byte[1024]; !6taOT>v  
int nRead; s 64@<oU<"  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) &`!H1E^  
{ \ D>!&  
nStartPos += fileAccessI.write(b,0,nRead); x^`P[>  
//if(nThreadID == 1) C.u)2[(  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Tsu\4 cL]  
} /i!/)]*-  
u1'l4VgT  
Wxj(3lg/  
Utility.log("Thread " + nThreadID + " is over!"); Wl&6T1A`"  
bDownOver = true; +sZY0(|K8  
//nPos = fileAccessI.write (b,0,nRead); FD~uUZTM  
} #Wl9[W/4  
catch(Exception e){e.printStackTrace ();} ~r})&`5  
} y9i+EV  
} `]6W*^'PD  
c.-dwz  
6~!7?FK  
//打印回应的头信息 KCa@0  
public void logResponseHead(HttpURLConnection con) W`#E[g?]  
{ %,8 "cM`D  
for(int i=1;;i++) 9QF,ynE  
{ s}gdi  
String header=con.getHeaderFieldKey(i); HN;f~EQT  
if(header!=null) +4IaX1.  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); %t.\J:WN;  
Utility.log(header+" : "+con.getHeaderField(header)); e9k$5ps  
else S}/ZHo  
break; Y)S f;  
} QUXr#!rPY|  
} XGnC8Be{4  
@&E7Pg5  
Ba%b]vp  
public void splitterStop() `ST;";7!  
{ N4yQ,tG>aa  
bStop = true; LmROG-9  
} 5C-n"8&C&  
>Zm|R|{BE  
vHymSU/J  
} <&1hJ)O  
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?[5_/0L,=  
/* sU^K5oo  
**FileAccess.java `9f7H  
*//文件访问(定位，写) Y$hLsM\%  
package NetFox; ~^~+p  
import java.io.*; '
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W\ARCcTQ  
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public class FileAccessI implements Serializable{ VRv.H8^{  
t<p4H
^  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 XPi5E"  
RandomAccessFile oSavedFile; NQbgk+&wD  
long nPos; Io7=Mc4  
y.Yni*xt/  
!1+!;R@&H>  
public FileAccessI() throws IOException Pf<BQ*n  
{ ~05(92bK  
this("",0); Oh=Kl3xs  
} c<)O#i@3/  
C !
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w^ 8^0i-  
public FileAccessI(String sName,long nPos) throws IOException f1Gyl  
{ gEq";B%?  
oSavedFile = new RandomAccessFile(sName,"rw"); g3'yqIjQL  
this.nPos = nPos; >ufN[
ab  
oSavedFile.seek(nPos); 4Z{ r  
} N?s5h?  
=fK F#^E@  
LgSVEQb6\|  
public synchronized int write(byte[] b,int nStart,int nLen) <qxqlEQT  
{ s(Fxi|v;  
int n = -1; S#ud<=@!9  
try{ 2cJ3b 0Xx  
oSavedFile.write(b,nStart,nLen); n]_<6{: U  
n = nLen; wcDb|
H&  
} +oa>k 0  
catch(IOException e) <;E>1*K}8  
{ Z#_VxA>]v  
e.printStackTrace (); $olITe"$g  
} G9c2kX.Bf  
-hO[^^i9  
='.G,aJ9  
return n; 0yKPYA*j  
} vo'{phtF)M  
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lHo
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} 4,6nk.$yN  
\8-PCD  
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/* F!6;<!&h  
**SiteInfoBean.java BIEeHN4  
*/ 8:Jc2K  
package NetFox; nc>Ae`"(  
6[C>"s}Ol  
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public class SiteInfoBean { q;qY#wD@  
JiHk`e`  
eRwm>l"fVV  
private String sSiteURL; //Site's URL ^Ea^t.c}_  
private String sFilePath; //Saved File's Path R)5zHCwOw  
private String sFileName; //Saved File's Name h<f]hJ`ep  
private int nSplitter; //Count of Splited Downloading File U3ao:2zP  
gl"1;C  
~f!iz~  
public SiteInfoBean() R`emI7|  
{//nSplitter的缺省值为5 DWar3+u&0  
//default value of nSplitter is 5 0%hOB:  
this("","","",5); 1ml{oqNj  
} bp(X\:zAy  
"+ 8Y{T  
?Kf?Z`9 *Y  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) "0A !fRI~  
{ L+$9 ,<'
[  
sSiteURL= sURL; T! fF1cpF\  
sFilePath = sPath; gJI(d6  
sFileName = sName; !T8h+3I  
this.nSplitter = nSpiltter; 9^1.nE(R&  
j.y
8H  
E6y ?DXWH  
} 73d7'Fw  
;AK@Kb  
}c0EGoU}?  
public String getSSiteURL() zJa,kN|m  
{ dWAKIBe  
return sSiteURL; 1Igo9rv  
} =L?(mNHT  
<gc\,P<ru  
qx3`5)ef  
public void setSSiteURL(String value) OBmmOswg~  
{ +zLh<q0  
sSiteURL = value; h4dT N}  
} WscNjWQ^TD  
75t5:>"[  
9zK5Y+!  
public String getSFilePath() ^ s@'nKc  
{ W"L;8u  
return sFilePath; ,~,{$\p   
} (#;<iu}  
N=P+b%%:Z  
F`\7&'I  
public void setSFilePath(String value) ZI'Mr:z4  
{ A#B6]j)  
sFilePath = value; Yhkn(k2  
} ^l"  
{:r8X  
H+ Y+8   
public String getSFileName() Kn<z<>vO  
{ vg/:q>o  
return sFileName; @`6db  
} a\m@I_r.N  
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public void setSFileName(String value) w$5#jJX\  
{ 3d|n\!1r  
sFileName = value; :. ja~Q  
} <MH| <hP  
0au\X$)Q  
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public int getNSplitter() GGR hM1II  
{ Nn;p1n dN  
return nSplitter; 'cx&:s  
} g5*Zg_G/  
M4:}`p=  
V=,VOw4  
public void setNSplitter(int nCount) u.s-/ g  
{ $zvqjT:>  
nSplitter = nCount; <U ?_-0  
} ZiS<vWa3R  
} TZ,kmk#
 
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/* s
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**Utility.java ITu6m<V  
*/ kM,$0@  
package NetFox; naT;K0T=  
. !|3a  
,\BGxGNAmV  
public class Utility { s2-p-n  
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public Utility() Q'~2,%3<  
{ Ox` +Z0)a  
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.D`""up|{  
} clZjb  
q! +?  
//线程睡眠 C?3?<FDL  
public static void sleep(int nSecond) [o=v"s't)  
{ ^sNj[%I R  
try{ \666{.a  
Thread.sleep(nSecond); /k(KA [bS  
} "c6(=FFq  
catch(Exception e)  OBY  
{ Q( C\X  
e.printStackTrace (); prC1<rm  
} }!-K)j.  
} C>vp oCA  
9*+%Qt,{B  
//日志 XD8MF)$9  
public static void log(String sMsg) tp,e:4\8Q  
{ +([ iCL  
System.err.println(sMsg); CmNd0S4v  
} NiwJ$Ah~X  
#O<2wMb2<  
s4RqMO5eI  
public static void log(int sMsg) ^uu)
|  
{ Olg@ Ri  
System.err.println(sMsg); :Qg3B ';  
} 52$7vYMto  
} "]dNN{Wka  
eJB !|  
[4qx+ypT  
/*  0~{&  
**TestMethod.java l0m\2Ttf  
*/ $~|#Rz%v  
package NetFox; :dtX^
IT  
.CClc(bO_/  
s.E}xv  
public class TestMethod { 4wZ{Z 2w  
CV~\xYY  
H h4G3h0  
public TestMethod() F]hKi`@  
{ ///xx/weblogic60b2_win.exe s:j"8ZH  
try{ ==[a7|q  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); $ePBw~yu  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); I$o^F/RH  
SiteFileFetch fileFetch = new SiteFileFetch(bean); *;~*S4/P   
fileFetch.start(); / ;U  
} B*+3A!{s  
catch(Exception e){e.printStackTrace ();} idLysxN  
QeYO)sc`  
K0#kW \4`  
} asDq(J`sQ  
lD;="b  
/-ebx~FX&  
public static void main(String[] args) (GVH#}uB  
{ Md9b_&'  
new TestMethod(); smpz/1U  
} :&#HrD[KT  
} v(vLk\K7  
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