http断点续传简单实现（java)

/* 7Ab&
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**SiteFileFetch.java 0vuL(W
8)  
*/ f.JZ[+  
package NetFox; mE'y$5ZxY  
import java.io.*; ye:pGa w  
import java.net.*; (4cWq!ax<$  
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@w
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public class SiteFileFetch extends Thread { {e\Pd!D?|  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 11[[HkX@  
long[] nStartPos; //开始位置 reR><p  
long[] nEndPos; //结束位置 C,~wmS )@  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 1j0OV9-|  
long nFileLength; //文件长度 1rKKph  
boolean bFirst = true; //是否第一次取文件 u\wdb^8ds  
boolean bStop = false; //停止标志 T]Z|Wq`bot  
File tmpFile; //文件下载的临时信息 s:3 altv  
DataOutputStream output; //输出到文件的输出流 #"-?+F=rk  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 0D/u`-  
public SiteFileFetch(SiteInfoBean bean) throws IOException (|)`~z  
{ c[\ :^w^I6  
siteInfoBean = bean; 4YDK`:4I~  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ~XN--4%Q  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); =}>wxO  
if(tmpFile.exists ()) Ls{z5*<FM  
{ ~\kJir  
bFirst = false; =y-L'z&r  
read_nPos(); IhnHNY]<g  
} e8g"QDc  
else uMVM-(g%  
{ _a1 =?  
nStartPos = new long[bean.getNSplitter()]; 28FC@&'H  
nEndPos = new long[bean.getNSplitter()]; u$ C@0d  
} !+T\}1f7d  
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;,P-2\V/  
} uT'_}cw  
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public void run() KiW4>@tY  
{ Vcn04j#Q  
//获得文件长度 <"A|Xv'Q  
//分割文件 AQn>K{M  
//实例FileSplitterFetch hoY.2 B_  
//启动FileSplitterFetch线程 7'u<)V  
//等待子线程返回 h/~:}Bof  
try{ !wiW#PR  
if(bFirst) RtVy^~=G  
{ _y#omEx  
nFileLength = getFileSize(); C yg e  
if(nFileLength == -1) gXr"],OM;  
{ [Du@go1C  
System.err.println("File Length is not known!"); T}} 0hs;  
} AA][}lU:5  
else if(nFileLength == -2) GMmz`O XN  
{ 50!/%  
System.err.println("File is not access!"); kN3T/96  
} u I$|M  
else dw %aoe  
{ d:/8P985  
for(int i=0;i<nStartPos.length;i++) vZV+24YWb  
{ 
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); D|8vS8p  
} m-f"EFmP  
for(int i=0;i<nEndPos.length-1;i++) A ?"(5da.  
{ _&S?uz m  
nEndPos = nStartPos[i+1]; ;>^oe:@  
} iku8T*&uc  
nEndPos[nEndPos.length-1] = nFileLength; _XT],"  
} '[#a-8-JY_  
} ~3}Gu^@  
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//启动子线程 %bI(  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; |8I
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for(int i=0;i<nStartPos.length;i++) 8r '  
{ .DSn H6O  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Zgp]s+%E  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ^l1tQnj)7  
nStartPos,nEndPos,i); 0_yE74i  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); shW$V93<  
fileSplitterFetch.start(); U3r[ysf  
} ( Lj{V}^  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), \)'nxFKqV  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); `|K,E  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", b?Wg|D  
nEndPos = " + nFileLength); 3L/qU^`  
// fileSplitterFetch[nPos.length-1].start(); =ark?<E  
(H*-b4]/  
"8K>Yu17  
//等待子线程结束 R'a%_sACj>  
//int count = 0; wu?ahNb.`Y  
//是否结束while循环 AH`n  
boolean breakWhile = false; @rs(`4QEh  
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while(!bStop) ?fv?6r  
{ qGMM3a)Q  
write_nPos(); ';`fMcN  
Utility.sleep(500); Ke-Q>sm2Q  
breakWhile = true; M0!;{1  
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for(int i=0;i<nStartPos.length;i++) \~xI#S@  
{ kg[u@LgvoN  
if(!fileSplitterFetch.bDownOver) Ke[doQ#c  
{ .(o]d{ '-}  
breakWhile = false; Li ,B,  
break; E_&Hje|J_[  
} ".L+gn}u-  
} ^q6H =Dl  
if(breakWhile) OJE<2:K  
break; :PtpIVAosg  
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//count++; XfA3Ez,}  
//if(count>4) E/cA6*E[.<  
// siteStop(); 70_T;K6  
} CCKg,v  
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System.err.println("文件下载结束！"); xO'I*)  
} ~45u a  
catch(Exception e){e.printStackTrace ();} E#"QaI8`  
} \C.%S +u  
1A^iUC5)  
i} 96,{  
//获得文件长度 P8NKpO\  
public long getFileSize() Rde_I`Ru  
{ >4TJH lB}8  
int nFileLength = -1; FzmCS@yA  
try{ k*|dX.C:  
URL url = new URL(siteInfoBean.getSSiteURL()); 2rHw5Wn]~  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Wu)ATs}  
httpConnection.setRequestProperty("User-Agent","NetFox"); iU^ 4a  
O;M_?^'W  
#oMbE<//"  
int responseCode=httpConnection.getResponseCode(); q!W~>c!  
if(responseCode>=400) ':#?YQ}2  
{ 20m6-rkI<}  
processErrorCode(responseCode); P Y +~,T2  
return -2; //-2 represent access is error d$ Mk  
} ezTu1-m  
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String sHeader; `XYT:'   
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for(int i=1;;i++) l^xkXj  
{ V5rnI\:7  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ^7q=E@[e
 
//Utility.log(in.readLine()); *pP"u::S  
sHeader=httpConnection.getHeaderFieldKey(i); 0kgK~\^,.O  
if(sHeader!=null) YN] w_=  
{ }7hpx!s,  
if(sHeader.equals("Content-Length")) ]SrKe-*:U  
{ [e)81yZG>  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); :w_F<2d0 0  
break; !boKrSw  
} 9CJUOB>]  
} Af=%5%  
else cNC\w%  
break; yWIieztp  
} GG"0n{>0  
} Js+d4``W  
catch(IOException e){e.printStackTrace ();} ^FgNg'"[3  
catch(Exception e){e.printStackTrace ();} J'9&dt  
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Utility.log(nFileLength); yG&kP:k<  
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return nFileLength; q<>2}[W  
} UEo,:zeN[  
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dQM# -t4*  
//保存下载信息（文件指针位置） js
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private void write_nPos() JmNeqpbB`w  
{ oE#HI2X  
try{ P},S[GaZ  
output = new DataOutputStream(new FileOutputStream(tmpFile)); %fP^Fh  
output.writeInt(nStartPos.length); ~b\7qx_a9  
for(int i=0;i<nStartPos.length;i++) JoW*)3Z  
{ p8s2#+/  
// output.writeLong(nPos); UShn)3F  
output.writeLong(fileSplitterFetch.nStartPos); U]vNcQj  
output.writeLong(fileSplitterFetch.nEndPos); (/YC\x
?  
} mk\U wv  
output.close(); i?=3RdP/R1  
} {DNc7G  
catch(IOException e){e.printStackTrace ();} rShi"Yw  
catch(Exception e){e.printStackTrace ();} *(?YgV  
} O#O~A|  
#a#~YSnG  
Aog3d\1$  
//读取保存的下载信息（文件指针位置） 0nx <f>n  
private void read_nPos() C,2IE
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{ h83ho  
try{ D\({]oj]  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 1+eC'&@Xjt  
int nCount = input.readInt(); -D:J$d 6R<  
nStartPos = new long[nCount]; CyG@  
nEndPos = new long[nCount]; %c^]Rdl  
for(int i=0;i<nStartPos.length;i++) h>mQ; L  
{ ItM?nyA  
nStartPos = input.readLong(); c09]Cp<  
nEndPos = input.readLong(); {w!}:8p
 
} um,/^2A  
input.close(); N)poe2[  
} ]`m|A1(  
catch(IOException e){e.printStackTrace ();} nr&G4t+%Hv  
catch(Exception e){e.printStackTrace ();} z*yN*M6t  
} {h9#JMIA  
);))kYr  
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private void processErrorCode(int nErrorCode) "6Dz~5  
{ n
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System.err.println("Error Code : " + nErrorCode); yE"hgdL  
} Slv}6at5  
~fCD#D2KU  
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//停止文件下载 0RoI`>j'  
public void siteStop() PtgUo,P  
{ SF_kap%JM  
bStop = true; sK?[1BI  
for(int i=0;i<nStartPos.length;i++) S}Mxm2  
fileSplitterFetch.splitterStop(); 8(3vNuyP  
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}  g<,v2A  
} ][G<CO`k  
//负责部分文件的抓取 ZLL0 6p   
**FileSplitterFetch.java Kq{s^G  
*/ ~S-x-cZ  
package NetFox; ?WAlW,H>  
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import java.io.*; ?R,^prW{  
import java.net.*; fd+
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h)y"?Jj  
:hMuxHr  
public class FileSplitterFetch extends Thread { m@zxjIwT  
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String sURL; //File URL _&F6As !{  
long nStartPos; //File Snippet Start Position /o|@]SAe.  
long nEndPos; //File Snippet End Position #ml
lVQ  
int nThreadID; //Thread's ID vjXvjv{t  
boolean bDownOver = false; //Downing is over ir]uFOj  
boolean bStop = false; //Stop identical PFPfLxna  
FileAccessI fileAccessI = null; //File Access interface 1Eg}qU,:  
8:t-I]dzk  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException i(c2NPbX  
{ tkuN$Jl  
this.sURL = sURL; l>=c]  
this.nStartPos = nStart; R8],}6,;E}  
this.nEndPos = nEnd; 'kh%^_FH7  
nThreadID = id; 4yBe(&N-d  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 #e9B|Y?b  
} ,%KB\;1mn'  
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public void run() tS!~>X  
{ H<NYm#a"  
while(nStartPos < nEndPos && !bStop) 1/&j'B  
{ *:&fw'vd,  
@#T?SNIL5  
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try{ 5T  
URL url = new URL(sURL); ?L'k2J  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); F5MWxAS,>  
httpConnection.setRequestProperty("User-Agent","NetFox"); s#d# *pgzh  
String sProperty = "bytes="+nStartPos+"-"; ZnJnjW PQ  
httpConnection.setRequestProperty("RANGE",sProperty); x(t}H8q  
Utility.log(sProperty); 55!9U:{  
^MddfBwk  
@8CD@SDv  
InputStream input = httpConnection.getInputStream(); ;<MaCtDt  
//logResponseHead(httpConnection); x%(!+  
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byte[] b = new byte[1024]; _OrE{  
int nRead; nEGku]pCH{  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) -Z;:_"&9  
{ Q`//
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nStartPos += fileAccessI.write(b,0,nRead); G)e 20Mst  
//if(nThreadID == 1) /4T%&#6s  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ?v")Z0 ~  
} IvO3*{k,  
,]cd%w9  
2#E;5UYu  
Utility.log("Thread " + nThreadID + " is over!"); *=sU+x&X  
bDownOver = true; *uv\V@0  
//nPos = fileAccessI.write (b,0,nRead); :ZzG5[o3  
} O!j@8~='  
catch(Exception e){e.printStackTrace ();} P0z "Eq0S  
} buhxC5i%  
} yqBu7E$X  
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//打印回应的头信息 b#y}VY)?  
public void logResponseHead(HttpURLConnection con) QWxQD'L'  
{ N\Hd3Om  
for(int i=1;;i++) pD>3c9J'^F  
{ J`x9XWYw  
String header=con.getHeaderFieldKey(i); kh5V&%>?  
if(header!=null) d")r^7  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 8WyG49eic  
Utility.log(header+" : "+con.getHeaderField(header)); ##n\9ipD  
else P,%|(qB
  
break; .9ROa#7U;n  
} S3=J1R,  
} *Zc-&Dk:Ir  
h5Z\9`f[  
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public void splitterStop() !PQRlgcG  
{ Mr1pRIYMd  
bStop = true; ' 5Ieqpm9  
} A9R}74e4g  
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} '+eP%Y[W%  
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/* S4(IYnwN  
**FileAccess.java S_QDYnF)`  
*//文件访问(定位，写) t^[{8,N  
package NetFox; L{Th>]X  
import java.io.*; bc"{ZL!C  
zH_q6@4  
*CG2sAeB  
public class FileAccessI implements Serializable{ Hv=coS>g:  
\.{JS>!  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 H}$#aXEAn  
RandomAccessFile oSavedFile; T8\,2UWsj2  
long nPos; %sq=lW5R{b  
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:{AN@zC0\  
public FileAccessI() throws IOException 4 '+)9&g  
{ ~W#f,mf  
this("",0); $K iMu  
} kQb0pfYs  
*\`C!r
 
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public FileAccessI(String sName,long nPos) throws IOException  [:k'VXL  
{ _m&VdIPO  
oSavedFile = new RandomAccessFile(sName,"rw"); ,S8Vfb &  
this.nPos = nPos; ysa"f+/  
oSavedFile.seek(nPos); 6RF01z|~_  
} ENmo^O#,u  
e}?t[aK4#  
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public synchronized int write(byte[] b,int nStart,int nLen) y
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{ a=J?[qrx  
int n = -1; 0N}5sF  
try{ s,}<5N]U  
oSavedFile.write(b,nStart,nLen); sDF J  
n = nLen; YU"Am !  
} 22
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catch(IOException e) \?g%>D:O;  
{ (r|T&'yK  
e.printStackTrace (); 7q?YdAUz  
} < d]|5  
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s=$7lYX  
return n; _5)#{o<  
} M{S7ia"s  
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} JC#@sJ4az)  
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G^R;~J*TDE  
/* Y}Dp{  
**SiteInfoBean.java DYl^6]  
*/ _(jE](,  
package NetFox; UqHOS{\Sz  
Ao\Vh\rQkq  
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public class SiteInfoBean { 9,Mp/.T"\  
k@~-|\ooG  
B -KOf  
private String sSiteURL; //Site's URL -{wuF0f  
private String sFilePath; //Saved File's Path H )}WWXK  
private String sFileName; //Saved File's Name bDkE*4SRX  
private int nSplitter; //Count of Splited Downloading File 8N`$7^^  
*"5a5.`%,  
`%Ghtm*  
public SiteInfoBean() y"hM6JI  
{//nSplitter的缺省值为5 MT5A%|He
 
//default value of nSplitter is 5 I%&9`ceWY  
this("","","",5); xo%iL  
} PHXP1)^}S  
t2:c@)  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) P=@lkF!\#  
{ w(U/(C7R  
sSiteURL= sURL; D6]$P%t9  
sFilePath = sPath; D7.
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sFileName = sName; K4yYNlY  
this.nSplitter = nSpiltter; =gn}_sKNE  
3oKGeB;Ja  
[0LqZ<\5  
} vz:0"y  
g?VME]:  
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public String getSSiteURL() kziBHis!  
{ a(~YrA%~  
return sSiteURL; u s0'7|{q  
} =tNiIU  
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l!y _P  
public void setSSiteURL(String value) D5>~'N3b  
{ (0Qq rNs  
sSiteURL = value; J9FNjM[qe  
} 5jQP"^g  
Fdw[CYHz  
,OCTm%6e  
public String getSFilePath() xdM#>z`;  
{ =Q}mJs  
return sFilePath; hn|E<  
} eh>E).  
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713M4CtJ  
public void setSFilePath(String value) nc~d*K\!  
{ 4sQAR6_SW~  
sFilePath = value; {?y7'  
} +E~`H^  
Z ~9N  
aTm.10{^  
public String getSFileName() weV#%6=5\  
{ pCUOeQL(  
return sFileName; zrO|L|F&P  
} ss{=::#  
ws?s  
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public void setSFileName(String value) m#$za7  
{ RM1uYFs<  
sFileName = value; 1$VI\}  
} (VAL.v*  
Pu*HZW3l
 
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public int getNSplitter() {l&2Kd*  
{ +fQL~0tA  
return nSplitter; =k=2~ j  
}  KdJx#Lc  
8{fz0H.<?  
50aWFJYw  
public void setNSplitter(int nCount) W+ '}O<  
{ zZc@;S#  
nSplitter = nCount; @1&;R  
} m'(;uR`  
} &9_\E{o%]  
Z)i1?#  
\seG2vw$  
/* "E|r3cN  
**Utility.java AOx3QgC^NO  
*/ $:E}Nj]{&  
package NetFox; j$8|ym^OX  
,PMb9O\B  
+%qSB9_>N{  
public class Utility { Qy^z*s  
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tc  
nuO3UD3  
public Utility() E'^]zW=9  
{ "gvw0)  
-V u/TT0  
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} e9`uD|KAS|  
$#7J\=GZ+  
//线程睡眠 b;J0'o^G|  
public static void sleep(int nSecond) Ls>u`hG  
{ 8yWu{'G
 
try{ 5\w=(c9A  
Thread.sleep(nSecond); .p(6' TYnI  
} s1Tl.p5  
catch(Exception e) a()6bRc~T  
{ ('
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e.printStackTrace (); [CDXCV-z  
} KZ!N{.Jk  
} g|._n  
-Y8ks7  
//日志 5fegWCJ  
public static void log(String sMsg) (K*/Vp  
{ gVa+.x]  
System.err.println(sMsg); -7k|6"EwM  
} Tr+h$M1_Ja  
Ld\LKwo  
@L[PW@:SZ  
public static void log(int sMsg) /lr1hW~Dbk  
{ jSie&V@px  
System.err.println(sMsg); x
&R9${e%  
} (ET ;LH3  
} @.Z
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+~w?Xw,  
<V$Y6(uMs  
/* 8tLT'2+H#  
**TestMethod.java \!UF|mD^tG  
*/ obAs<nk  
package NetFox; d; mmM\3]  
8! H8[J  
@],6SKbG6  
public class TestMethod { :BL'>V  
U|Bsa(?nx  
T_
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public TestMethod() p.rdSv(8'  
{ ///xx/weblogic60b2_win.exe mUrS&&fu8  
try{ ?w]"~   
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); /nC{)s?S'  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); [$( sUc(%  
SiteFileFetch fileFetch = new SiteFileFetch(bean); YN,y0t/cQ  
fileFetch.start(); vzY'+9q1.  
} ]aC':55(  
catch(Exception e){e.printStackTrace ();} %[]"QbF?  
oLrkOn/aY  
DKy>]Hca  
} {{V;:+62  
});cX$  
^))PCn_zb  
public static void main(String[] args) u}K5/hC  
{ MzEm*`<  
new TestMethod(); BIxV|\k  
} Ku<b0<`  
} bz,Da  
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