http断点续传简单实现（java)

/* [FLRrTcE  
**SiteFileFetch.java l1}=>V1  
*/ i6wLM-.)  
package NetFox; @dE|UZ=(  
import java.io.*; 9d{iq"*R  
import java.net.*; %RA8M- d  
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:9H=D^J  
public class SiteFileFetch extends Thread { f?: o  
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SiteInfoBean siteInfoBean = null; //文件信息Bean fk-zT
 
long[] nStartPos; //开始位置 W6f?/{Oo8  
long[] nEndPos; //结束位置 [*zB vj}G
 
FileSplitterFetch[] fileSplitterFetch; //子线程对象 HFYN(nz}[  
long nFileLength; //文件长度 qPsf
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boolean bFirst = true; //是否第一次取文件 YCod\}
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boolean bStop = false; //停止标志 >0kn&pe7#T  
File tmpFile; //文件下载的临时信息 =YlsJ={h  
DataOutputStream output; //输出到文件的输出流 ZrJAfd\5c  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） B6&PYMFK?*  
public SiteFileFetch(SiteInfoBean bean) throws IOException ^qXc%hjg  
{ B[jCe5!w  
siteInfoBean = bean; oiYI$ql3L  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); fR<_4L  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); >?K@zsv}  
if(tmpFile.exists ()) F VBuCi?W  
{ ("UcjB^62  
bFirst = false; "w] Bq0  
read_nPos(); R,[dEP  
} $%!'c# F  
else -'btKz*9  
{ $p@V1"x  
nStartPos = new long[bean.getNSplitter()]; }MBxfZ4I  
nEndPos = new long[bean.getNSplitter()]; dcUaZfON  
} W/COrgbW  
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cLl=?^DB  
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} Ft)7Wx" S  
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public void run() Xy[O  
{ ) jBPt&  
//获得文件长度 K?0f)@\nx  
//分割文件 Z 4,
nl  
//实例FileSplitterFetch @q0\oG4L  
//启动FileSplitterFetch线程 p^PAbCP'|3  
//等待子线程返回 lA}(63j+b  
try{ 0NlC|5ma)  
if(bFirst) LAqmM3{fA  
{ M3- bFIt  
nFileLength = getFileSize(); F|\^O[#R  
if(nFileLength == -1) x*GGO)r  
{ nxH+XHv  
System.err.println("File Length is not known!"); TZ8:3ti  
} Y?G9d6]Lk6  
else if(nFileLength == -2) _E0XUT!rA  
{ S*,DX~vig  
System.err.println("File is not access!"); BUR96YN.  
} ?B> {rj  
else Wt=QCutt  
{ `
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for(int i=0;i<nStartPos.length;i++) tow0/Jt  
{ nojJGeW%  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 4D(5WJ&  
} !p$z8~  
for(int i=0;i<nEndPos.length-1;i++) h:{rjXK  
{ 4%#Y)zo.e  
nEndPos = nStartPos[i+1]; V<&x+?>S  
} x {Z_rD  
nEndPos[nEndPos.length-1] = nFileLength;  A.nU8  
} c*LB=;npI  
} f5p>oXo4b  
Pi|WOE2  
# +OEO  
//启动子线程 Q/'jwyj_  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; K,f*}1$qM  
for(int i=0;i<nStartPos.length;i++) M*ZR+pq,  
{ )`;Q]?D   
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), c^$_epc*  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), LLE\;,bv  
nStartPos,nEndPos,i); dO/iL7K&  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); rH@{[~p  
fileSplitterFetch.start(); m~`d<RM/  
} rqJ'm?>cr  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), cm`Jr#kl{  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 
B!:%^S  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", yV`H_iC  
nEndPos = " + nFileLength); -Zs.4@GH  
// fileSplitterFetch[nPos.length-1].start(); Q+L;k R  
"9W]TG  
PvW {g5)S  
//等待子线程结束 \*] l'>x1  
//int count = 0; FvX<(8'#a  
//是否结束while循环 HLMcOuj  
boolean breakWhile = false; 5P=3.Mk  
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i=Nq`BoQf  
while(!bStop)
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{ -!d'!; ]  
write_nPos(); ^d2#J  
Utility.sleep(500); e5\/:HpI  
breakWhile = true; kn2s,%\`<p  
@PH`Wn#S  
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for(int i=0;i<nStartPos.length;i++) ]B8`b  
{ lG[@s 'j  
if(!fileSplitterFetch.bDownOver) =j,2  
{ -G\svwv@)  
breakWhile = false; $;GH -+  
break; Vl"20):  
} <%d/"XNg[D  
} |"}F cS y  
if(breakWhile) e:W]B)0/e  
break; `^3N|76Y  
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{J#SpG 7  
//count++; 0j{Rsy  
//if(count>4) =K#5I<x  
// siteStop(); JATW'HWC|I  
} dJvT2s.t[  
m |Isi  
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System.err.println("文件下载结束！"); l', +l{\Z  
} j@g`Pm%u`  
catch(Exception e){e.printStackTrace ();} ^,-2";2Xh  
} gX29
c  
RCZ"BxleU  
r{+P2MPW  
//获得文件长度 hJ~Na\?w  
public long getFileSize() :V,agAMn  
{ (!cG*FrN  
int nFileLength = -1; R1sWhB99  
try{ g|STegg  
URL url = new URL(siteInfoBean.getSSiteURL()); sd5%Szx  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ??Lda='  
httpConnection.setRequestProperty("User-Agent","NetFox"); E;`@S  
exW|c~|m{A  
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int responseCode=httpConnection.getResponseCode(); D*T*of G  
if(responseCode>=400) Ms4~P6;%  
{ gc<w nm|  
processErrorCode(responseCode); B3AWJ1o  
return -2; //-2 represent access is error /RG
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} k
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+8xC%eE  
String sHeader; !=uaB.  
G 6r2 "  
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for(int i=1;;i++) .ei5+?V<i  
{ a:v5(@8  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); LE@<)}Au^  
//Utility.log(in.readLine()); QUQw/  
sHeader=httpConnection.getHeaderFieldKey(i); Am'%tw ~  
if(sHeader!=null) M6nQ17\{  
{ b((>?=hh  
if(sHeader.equals("Content-Length")) Jn:h;|9w  
{ S4ys)!V1V  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); T]_]{%z  
break; ?)-#\z=6G  
} \&8 61A;  
} yg@8&;bP`  
else o=zr]vv  
break; =)c^ik%F&  
} {sOWDM5  
} #Sc9&DfX  
catch(IOException e){e.printStackTrace ();} o=]\Jy  
catch(Exception e){e.printStackTrace ();} MlKSjKl" !  
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Utility.log(nFileLength); aPToP.e  
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return nFileLength; M*gbA5  
} ln1!%B;  
+0l-zd\  
Q\W?qB_  
//保存下载信息（文件指针位置） {*PbD;/f  
private void write_nPos() WGwIc7  
{ 1IPRI<1U  
try{ '< .gKo  
output = new DataOutputStream(new FileOutputStream(tmpFile)); {j8M78}3  
output.writeInt(nStartPos.length); [4 v1 N  
for(int i=0;i<nStartPos.length;i++) cM_!_8o  
{ x DiGN Jc  
// output.writeLong(nPos); cjp~I/U  
output.writeLong(fileSplitterFetch.nStartPos); ,f@\Fs~n  
output.writeLong(fileSplitterFetch.nEndPos); xNd p]u  
} Oq9
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output.close(); B&+)s5hh  
} ,,c+R?D  
catch(IOException e){e.printStackTrace ();} ?E}9TQ  
catch(Exception e){e.printStackTrace ();} 1/3<u::  
} J#?`l,  
*'cyFu$  
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//读取保存的下载信息（文件指针位置） /(u# D[  
private void read_nPos() k>)Uyw$!  
{ J kxsua  
try{ hiKyU!)Hv  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); (f
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int nCount = input.readInt(); 6Zl#$>P  
nStartPos = new long[nCount]; wnU-5r&!]  
nEndPos = new long[nCount]; JfsvK2I  
for(int i=0;i<nStartPos.length;i++) ]iYO}JuX  
{ ]!X[[w)  
nStartPos = input.readLong(); S
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nEndPos = input.readLong(); dKQu  
} 3}}8ukq  
input.close(); 6_L<&RmLg  
} ^WkqRs  
catch(IOException e){e.printStackTrace ();} -A,UqEt  
catch(Exception e){e.printStackTrace ();} u[
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} /# d^  
9$#@Oe8*  
]++,7Z\AU  
private void processErrorCode(int nErrorCode) ,m Nd#  
{ d{Cg3v`Rd  
System.err.println("Error Code : " + nErrorCode); 9|WV28PK:  
} ][dst@?8Oz  
60G(jO14  
cTBUj  
//停止文件下载 tR\cS)  
public void siteStop() ZmDM
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{ cE^Ljk  
bStop = true; L0)w~F ?m  
for(int i=0;i<nStartPos.length;i++) %Jji<M]  
fileSplitterFetch.splitterStop(); fuU 3?SG  
USg,=YM  
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} \1O wZ@  
} GOsOFs"I  
//负责部分文件的抓取 #p<(2wN  
**FileSplitterFetch.java _fdD4-2U  
*/ =pBr_pGz=  
package NetFox; 9tWpxrig%  
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PA*1]i#2M=  
import java.io.*; 7_R[=t  
import java.net.*; ?3%r:
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public class FileSplitterFetch extends Thread { PLJDRp 2o  
..R JHa6B  
q`3HHq  
String sURL; //File URL eH V#Mey[  
long nStartPos; //File Snippet Start Position UX'q64F!  
long nEndPos; //File Snippet End Position ?_B'#,tI  
int nThreadID; //Thread's ID Zu*7t<W  
boolean bDownOver = false; //Downing is over G{!(2D4!  
boolean bStop = false; //Stop identical 4F"%X&$  
FileAccessI fileAccessI = null; //File Access interface u+O"c  
KF6N P  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Rk-G|52g  
{ zE Ly1v\"  
this.sURL = sURL; EbeSl+iMx_  
this.nStartPos = nStart; -,Js2+QZ#  
this.nEndPos = nEnd; ~z(0XKq0d  
nThreadID = id; nsM.`s@V  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 %d%FI"!K  
} *'*,mfk[  
?OPuv5!pI  
|~@yXc5a  
public void run() P!SsMo6n  
{ V,%K"b=  
while(nStartPos < nEndPos && !bStop) vJ{F)0 K  
{ F1S0C>N?5  
v 8EI   
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try{ (f2r4Io|}  
URL url = new URL(sURL); /#z"c]#  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 9C8 G(r  
httpConnection.setRequestProperty("User-Agent","NetFox"); $o.;}  
String sProperty = "bytes="+nStartPos+"-"; r0@s3/  
httpConnection.setRequestProperty("RANGE",sProperty); xSqr=^  
Utility.log(sProperty); *&tTiv{^  
2*< PmKI  
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InputStream input = httpConnection.getInputStream(); H& $M/`  
//logResponseHead(httpConnection); 6HPuCP  
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jZQ{XMF  
byte[] b = new byte[1024]; nly}ly Q/  
int nRead; 9f/l"  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) wwet90_g  
{ gi>W&6  
nStartPos += fileAccessI.write(b,0,nRead); 0e07pF/!  
//if(nThreadID == 1) IEd?-L  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); F-F1^$]k  
} H]W'mm  
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)H`V\H[0P  
Utility.log("Thread " + nThreadID + " is over!"); %Eugy  
bDownOver = true; ;n.h!wmJ}  
//nPos = fileAccessI.write (b,0,nRead); Nobu= Z  
} g<ov` bF  
catch(Exception e){e.printStackTrace ();} "[rz*[o8I  
} &grvlK  
} H )>3c1  
lWH#/5`h  
Bt#'6::  
//打印回应的头信息 @FZ_[CYg  
public void logResponseHead(HttpURLConnection con) ~N/a\%`  
{ ZNl1e'  
for(int i=1;;i++) Vc6 >i|"-O  
{ +*Fe   
String header=con.getHeaderFieldKey(i); D>^g2!b:  
if(header!=null) lD->1=z  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ^QjkZ^<dD  
Utility.log(header+" : "+con.getHeaderField(header)); 4e?bkC  
else H DD)AM&p  
break; &E
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} >j7]gi(  
} t
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.beqfcj"  
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public void splitterStop() ?bu=QV@  
{ p5py3k  
bStop = true; )*R';/zaI  
} MIyT9",Pl  
,
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} .LDp.#d9r1  
LitdO>%#2  
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/* +sTPTCLE  
**FileAccess.java 4<vi@,s  
*//文件访问(定位，写) I(WIT=Wi<  
package NetFox; $RB p!7  
import java.io.*; @nMVs6  
^7*7^<  
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public class FileAccessI implements Serializable{ )p
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LE)$_i8gX  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 @Kn@j D;  
RandomAccessFile oSavedFile; *z#du*f[  
long nPos; )m[<lJbw  
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s&'FaqE  
public FileAccessI() throws IOException |lZJt  
{ Fa\jVFIQ  
this("",0); ?Z4%u8Krvz  
} Vy|4k2
 
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public FileAccessI(String sName,long nPos) throws IOException AlG5n'  
{ i~AReJxt7  
oSavedFile = new RandomAccessFile(sName,"rw"); Gg]Jp:GF  
this.nPos = nPos; %rgW}Z5  
oSavedFile.seek(nPos); =F Y2O`%a  
} pq\N2d  
ASrRMH[  
qJf\,7m
i  
public synchronized int write(byte[] b,int nStart,int nLen) 8h4]<T  
{ "nb.!OG~(  
int n = -1; ~R~.D  
try{ ~)`\j  
oSavedFile.write(b,nStart,nLen); @$ju Qm  
n = nLen; ].5q,A]  
} *9w-eK1{  
catch(IOException e) M#-E  
{ x,cvAbwS  
e.printStackTrace (); $cc]Av4c2  
} z]C=nXbk  
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L, #|W  
return n; C@Go]*c  
} ;"ESN)*|i  
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} nT+ZSr  
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Y  
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/* lKQevoy'  
**SiteInfoBean.java c#`IF6qj  
*/ dFhyT.Y?  
package NetFox; m[iQ7/  
md? cvGDE  
#qR6TM&;  
public class SiteInfoBean { 5XzsqeG|  
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'RF`XX  
private String sSiteURL; //Site's URL @V:Y%#%  
private String sFilePath; //Saved File's Path z}.6yHS  
private String sFileName; //Saved File's Name Rm79mh9  
private int nSplitter; //Count of Splited Downloading File } XhL`%  
?*yB&(a:8  
*h=>*t?I2  
public SiteInfoBean() q86}'dFw{  
{//nSplitter的缺省值为5 vD:J!|hs(  
//default value of nSplitter is 5 :ir3u  
this("","","",5); YTmHht{j#  
} \%bJXTK&W  
(=fLWK{8  
Lj#xZ!mQS  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) qO8:|q1%;\  
{ V/#J>-os}W  
sSiteURL= sURL; rIYO(}Fl  
sFilePath = sPath; HS ]c~  
sFileName = sName; /':64#'  
this.nSplitter = nSpiltter; /'E[03I~  
J~ome7L  
{fHY[8su0  
} NWPT89@l  
/{jt]8/;7  
yzT1Zg_ER  
public String getSSiteURL() 2kDv (".  
{ -K(d]-yv  
return sSiteURL; Zlh 2qq  
} C& XPn;f  
_j3rs97@|  
#Ha"rr46p  
public void setSSiteURL(String value)  bKK'U4  
{ %eW7AO>  
sSiteURL = value; jb,a>9]p  
} 4b;*:C4?  
]h' 38W  
.-mIU.Nwi  
public String getSFilePath() 3N+B|WrM  
{ j[FB*L1!D  
return sFilePath; b]Kb ~y|  
} 9L3P'!Z  
~o|sma5.  
o@_i&4[MW  
public void setSFilePath(String value) ]B3+&g  
{ 2yZ~j_AF[  
sFilePath = value; m ie~. "  
} XTk :lzFH  
|2n*Ds'  
im9EV|;  
public String getSFileName() pU<J?cU8N  
{ b
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return sFileName; w+)wrJTtm  
} zTfjuI|R  
~6Fh,S1?  
Q&w_kz.  
public void setSFileName(String value) -3~S{)  
{ 2RF3pIFrm  
sFileName = value; [g<gu~  
} ;<''oY  
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X[H.t$w5A  
public int getNSplitter() 7-n HP
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{ V9}\0joM  
return nSplitter; eq8faC5  
} S{8-XiL,  
<t
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+v5f-CBu  
public void setNSplitter(int nCount) skan1wQ  
{ RMpiwO^  
nSplitter = nCount; WN%,  
} *{k
{  
} IDw`k[k  
%saP>]o  
DbB<8$  
/* \b"|p%CL8  
**Utility.java hEZo{0:b"  
*/ 9I [:#,zdf  
package NetFox; 50Gu~No6  
!\d~9H%`B  
^>!&]@  
public class Utility { *S}CiwW>/  
)m8Gbkj<  
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public Utility() SFtcO  
{ (G} }h  
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} /ar0K9`c  
&Z!y>k%6
 
//线程睡眠 yih|6sd$F  
public static void sleep(int nSecond) 2Og5e  
{ ,xrA2  
try{ cT@| $A  
Thread.sleep(nSecond); >eo[)Y  
} ||TZ[l  
catch(Exception e) ):Z#!O<  
{ oMLs22Do?  
e.printStackTrace (); p^q/u  
} pV(Mh[ }P  
} YU+P+m2X  
N#RC;  
//日志 1,$"'lKwt  
public static void log(String sMsg) X[$|I9  
{ %g5#q64  
System.err.println(sMsg); J!6w9,T_  
} >b9J!'G,(  
*q,nALs  
 E^5  
public static void log(int sMsg) mS;WNlm\  
{ -}j(_]t  
System.err.println(sMsg); )p;t '
*]  
} 8EdaqF  
} [bX^_ Y  
dyf>T}Iy  
FW;}S9u3  
/* -:'%YHxX  
**TestMethod.java NT5##XOB  
*/ hWFOed4C  
package NetFox; >Z3>  
:*[mvF  
4 $Kzh  
public class TestMethod { ._A4:  
&J|I&p   
2-ksr}
:  
public TestMethod() |Rx+2`6Dp  
{ ///xx/weblogic60b2_win.exe g{sp<w0  
try{ 4Hb
"yp$  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); {` bX*]  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); eFf9T@  
SiteFileFetch fileFetch = new SiteFileFetch(bean); q&&"8.w-  
fileFetch.start(); U&Atgv  
} U=j`RQ 9,  
catch(Exception e){e.printStackTrace ();} "+qZv
(  
>FHx],  
ZlE=P4`X:  
} :8}Qt^p  
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public static void main(String[] args) R=, pv'  
{ xW9R-J\W  
new TestMethod(); k'&1,78[l  
} mC\<fo-u  
} ?6ssSjR}  
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