http断点续传简单实现（java)

/* qYLOq`<f  
**SiteFileFetch.java U{n< n8  
*/ 2)(P;[m^o  
package NetFox; r J'm>&Ps  
import java.io.*; vB(tpki|  
import java.net.*; H@%Y!z@\  
* bx%hX  
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public class SiteFileFetch extends Thread { lgp-/O"T  
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SiteInfoBean siteInfoBean = null; //文件信息Bean PEZ~og:w  
long[] nStartPos; //开始位置 [|<2BQX  
long[] nEndPos; //结束位置 RGy4p)z*+  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 }|>mR];  
long nFileLength; //文件长度 zM?JLNs]<{  
boolean bFirst = true; //是否第一次取文件 Vh1{8'GQ  
boolean bStop = false; //停止标志 `iuo([E d  
File tmpFile; //文件下载的临时信息 }ybveZxv5A  
DataOutputStream output; //输出到文件的输出流 @+1-_Q`s/R  
m'H%O-h\  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） v7"' ^sZ?  
public SiteFileFetch(SiteInfoBean bean) throws IOException Wi]Mp7b  
{ ]0<T,m Z  
siteInfoBean = bean; cd,)GF  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); s\g"~2+  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); gd3~R+Kd  
if(tmpFile.exists ()) 6u^MfOc  
{ rxtp?|v9  
bFirst = false; M;*f(JY$  
read_nPos(); {2?o:  
} n`<YhV  
else %|md0  
{ E?san;Ku  
nStartPos = new long[bean.getNSplitter()]; g2p/#\D\J  
nEndPos = new long[bean.getNSplitter()]; 4r5trquC  
} !uoU 8Ki9  
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} '&4W@lvyz  
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public void run() P wL]v.:  
{ d>@&[C!28  
//获得文件长度 @MMk=/WDw  
//分割文件 DEEQ/B{  
//实例FileSplitterFetch p<IMWe'tP  
//启动FileSplitterFetch线程 7,U^v}$  
//等待子线程返回 ?:F#WDD  
try{ Z^w11}  
if(bFirst) U6V+jD}L]  
{ g2;!AI5f  
nFileLength = getFileSize(); #`R`!4  
if(nFileLength == -1) )=6|G^  
{ ~_^#/BnAl  
System.err.println("File Length is not known!"); k fS44NV  
} 0 =#)-n  
else if(nFileLength == -2) /Zs;dam  
{ 1s5FjD?M  
System.err.println("File is not access!"); QV/o;  
} WO{V,<;  
else hd*bPj;  
{ Kp[
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for(int i=0;i<nStartPos.length;i++) Ul#||B .c{  
{ @C7iflo6  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ht _fbh(l  
} rMkoE7n  
for(int i=0;i<nEndPos.length-1;i++) !#P|2>>u  
{ 63R?=u@  
nEndPos = nStartPos[i+1]; _kR);\V.8  
} yxq+<A4,a  
nEndPos[nEndPos.length-1] = nFileLength; kGbtZ} W  
} d%tF~|#A%  
} K^0cL%dB  
c zTr_>
  
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//启动子线程 lt 74`9,f  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; e@[9WnxYe  
for(int i=0;i<nStartPos.length;i++) &qfnCM0Y  
{ *3 .+19Q  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), gaeMcL_^a  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 8!87p?Mz  
nStartPos,nEndPos,i); R_iQLBr
d  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); D{1k{/cF  
fileSplitterFetch.start(); oJ}!qrrH  
} Qu4Bd|`(k  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), et[n;nl>V  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 6`(x)Q9  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", w6ZyMR,T  
nEndPos = " + nFileLength); Y>v(UU  
// fileSplitterFetch[nPos.length-1].start(); bs{i@1$  
];cJIa  
+ ;u<tA  
//等待子线程结束 )+ }\NCFh  
//int count = 0; D*!p8J8Ku  
//是否结束while循环 Ak(_![Q:q\  
boolean breakWhile = false; {s^vAD<~x3  
s~OGlPK  
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while(!bStop) MVe:[=VOT|  
{ w
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write_nPos(); C>\0 "}iD  
Utility.sleep(500); d&mSoPf  
breakWhile = true; " sh%8 <N  
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$Pw@EC]  
for(int i=0;i<nStartPos.length;i++) t As@0`x9  
{ K/)*P4C-  
if(!fileSplitterFetch.bDownOver) ' fXBWi6  
{ 72J@Dc  
breakWhile = false; Y`$dtg {  
break; 3/+r*lv>X  
} qfF/X"#
0  
} 1CS[%)-c  
if(breakWhile) 3q +C8_:  
break; t;?M#I\,{  
;+pS-Zb 6  
N>8pA)  
//count++; Z4+S4cqnh  
//if(count>4) d4'*K1m   
// siteStop(); Gwl]sMJ  
} /F#_~9JXG  
h>jLhj<07W  
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System.err.println("文件下载结束！"); tu.Tvtudzj  
} & w%%{lM  
catch(Exception e){e.printStackTrace ();} RY8Ot2DWi  
} 46U?aHKW@|  
"Me)'  
Snm m(.  
//获得文件长度 R.KqTEs<k  
public long getFileSize() <zmtVE*>g  
{ 0#K?SuY.eN  
int nFileLength = -1; ;%u'w;sgq  
try{ +C`h*%BW  
URL url = new URL(siteInfoBean.getSSiteURL()); Grot3a  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); :-Gf GL>]  
httpConnection.setRequestProperty("User-Agent","NetFox"); a;},y|'E  
879x(JII  
O0|**Km\+  
int responseCode=httpConnection.getResponseCode(); -p|JJx?r  
if(responseCode>=400) ]#)1(ZE  
{ RPH]@  
processErrorCode(responseCode); Ps<6kQ(  
return -2; //-2 represent access is error !Db0r/_:G  
} P(H,_7 4  
?|Q[QP  
_oOEMQb  
String sHeader; 9wR-0E )  
vkFfHzR$  
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for(int i=1;;i++) @|yRo8|  
{ 8&q|*/2  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 2|J>e(&akY  
//Utility.log(in.readLine()); F_KPhe$  
sHeader=httpConnection.getHeaderFieldKey(i); kzZdYiC  
if(sHeader!=null) N*d )<8_  
{ m53XN  
if(sHeader.equals("Content-Length")) HH_w!_f  
{ %O9kq  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); +o{]0~y  
break; -N'xQ(#n3q  
} bf~gWzA  
} m(~5X0  
else \W"N{N  
break; ;QMRm<CLV  
} Gp}:U>V)  
} #;4afj:2g  
catch(IOException e){e.printStackTrace ();} Z0fl]3p  
catch(Exception e){e.printStackTrace ();} K|"97{*|2  
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Utility.log(nFileLength); a'sa{>  
/^#8z(@B  
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return nFileLength; G@4ro<  
} {|Ew]Wq  
{Ac5(li_  
@fDWp/  
//保存下载信息（文件指针位置） ZS\jbii8  
private void write_nPos() K YSyz)M}  
{ BQ&G7
V  
try{ u!NY@$Wc  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ([Gb]0  
output.writeInt(nStartPos.length); v%mAU3M  
for(int i=0;i<nStartPos.length;i++) ze%kP#c6!  
{ `RRC8]l  
// output.writeLong(nPos); RTHe#`t  
output.writeLong(fileSplitterFetch.nStartPos); %Se@8d8  
output.writeLong(fileSplitterFetch.nEndPos); 6fP"I_c  
} v0~'`*|&  
output.close(); wUnz D)  
} ?Hb5<,1u3  
catch(IOException e){e.printStackTrace ();} p&Os5zw;|  
catch(Exception e){e.printStackTrace ();} D{%l 4og  
} fgmu*\x<  
Fpz)@0K;  
Equj[yw%@  
//读取保存的下载信息（文件指针位置） /h)_Q;35S;  
private void read_nPos() <"Ox)XG3]W  
{ eB]cPo4gW  
try{ tbx* }uy2  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ^h q?E2-  
int nCount = input.readInt(); W u4` 3  
nStartPos = new long[nCount]; 
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nEndPos = new long[nCount]; }N^A (`L  
for(int i=0;i<nStartPos.length;i++) Idy{(Q  
{ vr/O%mD
p  
nStartPos = input.readLong(); )qgcz<p?W  
nEndPos = input.readLong(); ^qn,b/>L  
} 3~Qvp )~  
input.close(); ?Cg",k'  
} \KBE+yj  
catch(IOException e){e.printStackTrace ();} ~/R,oQ1!g}  
catch(Exception e){e.printStackTrace ();} O'<5PwhG  
} @P
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4#pn]  
[| \Z"   
private void processErrorCode(int nErrorCode) -k$
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{ r2KfZ>tWg"  
System.err.println("Error Code : " + nErrorCode); g{t)I0xm  
} '}\#bMeObg  
h.A@o#x  
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//停止文件下载 \Lp|S:u  
public void siteStop() 3LxhQVx2  
{ (?9@nS  
bStop = true; })I_@\q  
for(int i=0;i<nStartPos.length;i++) !B&OK&*  
fileSplitterFetch.splitterStop(); M Y2=lT  
a>3#z2#  
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} #84<aM  
} )#^5$5  
//负责部分文件的抓取 -r.Qy(}p  
**FileSplitterFetch.java .7h:/d Y:  
*/ &#keI.,  
package NetFox;  j|Q*L<J  
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@ m' zm:  
import java.io.*; xJ2DkZ  
import java.net.*; +#|| w9p  
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public class FileSplitterFetch extends Thread { aan)yP  
O{4G'CgN(  
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String sURL; //File URL **oaR  
long nStartPos; //File Snippet Start Position mz|#K7:  
long nEndPos; //File Snippet End Position M_<? <>|  
int nThreadID; //Thread's ID T
#HW{3  
boolean bDownOver = false; //Downing is over ]c67zyX=%  
boolean bStop = false; //Stop identical D*!UB5<>/t  
FileAccessI fileAccessI = null; //File Access interface I}?+>cf  
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}bU1wIW9I  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Bl\/q83(  
{ B)q 5m y  
this.sURL = sURL; 7GY3_`  
this.nStartPos = nStart; Ne 2tfiI`  
this.nEndPos = nEnd; *B$$6'hi`  
nThreadID = id; 91|0{
1  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 !Vtj:2PQL  
} 'Gr}<B$A3  
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public void run() OoG Nij  
{ 5<Lal^c D  
while(nStartPos < nEndPos && !bStop) 2 Nr*  
{ &d!Q%  
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try{ iSiez'  
URL url = new URL(sURL); _4Ciai2Ql  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); " R=,W{=  
httpConnection.setRequestProperty("User-Agent","NetFox"); #it)  
String sProperty = "bytes="+nStartPos+"-"; 2YS1%<-g*  
httpConnection.setRequestProperty("RANGE",sProperty); T>$S&U  
Utility.log(sProperty);
^ UB*Q  
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InputStream input = httpConnection.getInputStream(); <-Hw@g  
//logResponseHead(httpConnection); PP]Z~ne0X  
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byte[] b = new byte[1024]; Te\i;7;4u  
int nRead; lR
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while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) qHU=X"rn  
{ {.,-lFb\  
nStartPos += fileAccessI.write(b,0,nRead); 2@W'q=+0  
//if(nThreadID == 1) 3Z taj^v  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); pA~eGar_J  
} +\Zr\fOe|%  
j\/Rjn+:[  
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Utility.log("Thread " + nThreadID + " is over!"); .%\lYk]  
bDownOver = true; i_[nW  
//nPos = fileAccessI.write (b,0,nRead); $,s"c(pv[,  
} :iKk"r,2P[  
catch(Exception e){e.printStackTrace ();} xE0'eC5n^  
} 0@BhRf5  
} ::&hfHR*P  
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n'i~1pM,?  
//打印回应的头信息 1kX>sajp~  
public void logResponseHead(HttpURLConnection con) ,; 81FK  
{ bvR0?xnq  
for(int i=1;;i++) !_a@autj  
{ RTXl3 jq  
String header=con.getHeaderFieldKey(i); /:BM]K  
if(header!=null) q]^Q?r<g::  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); /'g/yBY  
Utility.log(header+" : "+con.getHeaderField(header)); `P(Otr[6  
else pS) &d4i  
break; ]b&"](A  
} vz87]InI  
} zCuN8  
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public void splitterStop() 5GHW~q!Zo\  
{ FN>ns,  
bStop = true; usFhcU  
} K+F]a]kld  
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} i& phko}  
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/* "m'roU  
**FileAccess.java KhWt9=9  
*//文件访问(定位，写) sf(2~BMQI  
package NetFox; U6sPJc<  
import java.io.*; bS2)L4MQY  
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#]MV  
public class FileAccessI implements Serializable{ Y!0ZwwW  
:5 zXW;s  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 {0?]weN*  
RandomAccessFile oSavedFile; ;vkk$ -  
long nPos; ]NRQM8\  
:jP4GCxU|  
%s(Ri6R&  
public FileAccessI() throws IOException D'UYHc{  
{ ;bh[TmQTJ  
this("",0); uJg|  
} |GqKa  
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g"P!KPrf1p  
public FileAccessI(String sName,long nPos) throws IOException 4Ww.CkRG  
{ V39`J*fI  
oSavedFile = new RandomAccessFile(sName,"rw"); D(YNa  
this.nPos = nPos; :OFL@byS  
oSavedFile.seek(nPos); wgV?1S>Z  
} >oOZDuj  
<aVfgVS  
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public synchronized int write(byte[] b,int nStart,int nLen) )=EJFQ*v  
{ '{I YANVT  
int n = -1; 5m(V(@a3  
try{ fcLVE  
oSavedFile.write(b,nStart,nLen); TQjM3Ri=V  
n = nLen; p>#QFd"m  
} S@WzvM  
catch(IOException e) x_eR/B>  
{ 0.4Q-?J  
e.printStackTrace (); &|j^?ro6  
} tXu_o6]  
-sqoE*K[8  
UwQyAD]Ht  
return n; $SAk|  
} Y{v\m(D  
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to%n2^^K  
} @4ECz>Q  
!JOM+P:  
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/* g~Hmka_fD1  
**SiteInfoBean.java
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*/ ^@a|s Sb  
package NetFox; XSDudL  
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public class SiteInfoBean { m@2;9  
+:#x!i;W8[  
v_s(  
private String sSiteURL; //Site's URL G
i9s*v,s  
private String sFilePath; //Saved File's Path QaAWO  
private String sFileName; //Saved File's Name 'nR'o /!  
private int nSplitter; //Count of Splited Downloading File "7RnT3  
.V.x0  
nxZ[E.-\  
public SiteInfoBean() 2TxHY|4  
{//nSplitter的缺省值为5 dEuts*@Q  
//default value of nSplitter is 5 #y4+O;{  
this("","","",5); Ki_8
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} O*%@(w6  
',g'Tl^E  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) j1Q"s(  
{ i[\`]C{gf  
sSiteURL= sURL; DGY?4r7>y  
sFilePath = sPath; S.$/uDwo  
sFileName = sName; #rs]5tx([  
this.nSplitter = nSpiltter; b+rn:R  
6_#:LFke  
=iEQE  
} `r$c53|<u  
k:JlC(^h  
cI
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public String getSSiteURL() 9R6]OL)p  
{ /O$7A7Tl
 
return sSiteURL; 6$k"B/k  
} k9|8@3(h  
y))) {X  
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public void setSSiteURL(String value) TTSyDl  
{ 1[&V6=n  
sSiteURL = value; }kK6"]Tj  
} %x2_njDd  
]3/_?n-"`  
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public String getSFilePath() &P,z$H{o@  
{ ZNX=]]HM<n  
return sFilePath; 6k@(7Mw8A  
} m
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btV Tt5  
nR2pqaKc  
public void setSFilePath(String value) $ZEwz;HNo  
{ :w+2L4lGs  
sFilePath = value; ]LE  
} `YinhO:Z  
OlwORtWzZ  
^ rB7&96C,  
public String getSFileName() 2[;4D/`*  
{ GqT0SP  
return sFileName; jLy3c@Dp  
} Y>l92=G  
ee+*&CT)  
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public void setSFileName(String value) 2VgDM6h  
{ d>f.p"B.gj  
sFileName = value; i7UE9Nyl*  
} >cE@m=[  
.e,(}_[[<  
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public int getNSplitter() cp&- 6 w+  
{ @-ms_Z  
return nSplitter; UDUj  
} wj$J}F  
5jb/[i^V  
"iC*Eoz#.  
public void setNSplitter(int nCount) \~O}V~wE  
{ AdWLab;  
nSplitter = nCount; @2>j4Sc  
} P`$"B0B)  
} yL#bZ9W }  
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#go!"HL  
/* l\NVnXv:>  
**Utility.java P0 va=H  
*/ zxV,v*L)  
package NetFox; -q}c;0vL-a  
9PM\D@A{  
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public class Utility { =(-oQ<@v  
@/w($w"  
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public Utility()
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{ -ST[!W V  
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c~0hu*&  
} r/32pY  
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//线程睡眠 Rpi@^~aPE  
public static void sleep(int nSecond) *_aeK~du.  
{ x2KIGG^  
try{ O$2'$44HX  
Thread.sleep(nSecond); b\dzB\,&  
} etPb^&#$  
catch(Exception e) EzXGb  
{ J=*X%^jX9Z  
e.printStackTrace (); <H,q( :pM  
} ^zv,VD  
} .+'`A"$8  
LWpM-eW1q  
//日志 c5($*tTT  
public static void log(String sMsg) has \W\(  
{ ^F*G  
System.err.println(sMsg); h5x_Vjj  
} +].Zs<  
T/A[C  
qNH= W?T8.  
public static void log(int sMsg) $eI=5
 
{ Fk(+S:{yQ  
System.err.println(sMsg); CflGj0oy8  
} 7<ZP(I5X  
} \G!TC{6  
"'@iDq%y  
cr&sI=i  
/* SXA`o<Ma  
**TestMethod.java iEtnwSt  
*/ L~,x~sLd  
package NetFox; mX2(SFpJar  
}! jk  
~ PO)>;  
public class TestMethod { <Ag`pZ<s  
N<e=!LV  
'\&t3?;  
public TestMethod() Oc51|[ Wj  
{ ///xx/weblogic60b2_win.exe W[dK{?RB  
try{ 4FWb5b!A=  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); <vP{U  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 2itJD1;  
SiteFileFetch fileFetch = new SiteFileFetch(bean); =lE_ Q[P  
fileFetch.start(); vw;GbQH(  
} sO5~!W>Z  
catch(Exception e){e.printStackTrace ();} (sXR@Ce$  
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0E6tH& ;>  
} Jvk!a~e  
nkv+O$LXP  
dK5|tWJX  
public static void main(String[] args) Q :<&<i=I  
{ ^UB<U#8,  
new TestMethod(); ':}  
} xXCSaBS~  
} g3}K  
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