http断点续传简单实现（java)

/* fOrH$?  
**SiteFileFetch.java 0mVNQxHI  
*/ Z{d^-  
package NetFox; ~~P5k:  
import java.io.*;
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import java.net.*; Zx@a/jLO[n  
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public class SiteFileFetch extends Thread { $PPi5f}HD  
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SiteInfoBean siteInfoBean = null; //文件信息Bean j$:~Rek  
long[] nStartPos; //开始位置 00y!K m_D  
long[] nEndPos; //结束位置 uzPVTo|=  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 #{6/ (X  
long nFileLength; //文件长度 xo&_bMO  
boolean bFirst = true; //是否第一次取文件 mJnIwdW*  
boolean bStop = false; //停止标志 BxmWIItz  
File tmpFile; //文件下载的临时信息 ;'K5J9k  
DataOutputStream output; //输出到文件的输出流 w&#]
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*fxG?}YT  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） @.l@\4m  
public SiteFileFetch(SiteInfoBean bean) throws IOException {P./==^0  
{ aXYY:;  
siteInfoBean = bean; e T{ 4{  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); xCTML!H  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); RqrdAkg  
if(tmpFile.exists ()) P@B]

 
{ \\qZl)P_  
bFirst = false; 59A}}.@?m  
read_nPos(); )akoa,#%6c  
} LL!Dx%JZ  
else 7}>EJ  
{ ki!0^t:9  
nStartPos = new long[bean.getNSplitter()]; "^-a M  
nEndPos = new long[bean.getNSplitter()]; WT=;:j  
} SnfYT)Ph  
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} niyV8
v  
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public void run() Otuf]B^s  
{ +\9NDfYIA  
//获得文件长度 H <l7ZS:  
//分割文件 a=2%4Wmz  
//实例FileSplitterFetch ##*3bDf$-5  
//启动FileSplitterFetch线程 R 9\*#c  
//等待子线程返回 +<C!U'  
try{ K%oG,-wdg  
if(bFirst) D,feF9  
{ ?tbrbkx  
nFileLength = getFileSize(); 5j(k:a+!H  
if(nFileLength == -1) ~>|ziHx  
{ 8Z~EwY*  
System.err.println("File Length is not known!"); %h@EP[\  
} &8lZNv8;(p  
else if(nFileLength == -2) e7 o.x
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{ 3w'tH4C[Y  
System.err.println("File is not access!"); K0>zxqY  
} g- gV
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else k,*XG$2h  
{ mzgfFNm^G)  
for(int i=0;i<nStartPos.length;i++) Zy/_ E@C}u  
{ KWHY4  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 7[)E>XRE  
} 4WB
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for(int i=0;i<nEndPos.length-1;i++) fJg+Ryo  
{ UK!(G  
nEndPos = nStartPos[i+1]; n[rCQdM&U"  
} $UwCMPs X  
nEndPos[nEndPos.length-1] = nFileLength; ]f_p8?j"  
} 9*M,R,y  
} @yYkti;4-  
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//启动子线程 l/5 hp.  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ^cWnF0)j.  
for(int i=0;i<nStartPos.length;i++) oB7_O-3z  
{ _[BP0\dPW  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), hZb_P\1X  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), /n&&Um\  
nStartPos,nEndPos,i); @0''k  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ;uGv:$([g  
fileSplitterFetch.start(); *;FdD{+  
} "AqB$^S9t  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ~xTt204S  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); KI.hy2?e  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", d'> x(Yi  
nEndPos = " + nFileLength); ~W/z96' 5  
// fileSplitterFetch[nPos.length-1].start(); *-X[u
:  
-{vD:Il=6  
L~3Pm%{@A  
//等待子线程结束 7tp36TE  
//int count = 0; ]4e;RV-B  
//是否结束while循环 /-s6<e!  
boolean breakWhile = false; zQ PQ  
=_^X3z0  
Ny#^&-K  
while(!bStop) LP=)~K
<  
{ J}t%p(mb  
write_nPos(); 7+*WH|Z@  
Utility.sleep(500); dh\P4  
breakWhile = true; O6Y0XL  
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for(int i=0;i<nStartPos.length;i++) xSu >  
{ 6LhTBV
 
if(!fileSplitterFetch.bDownOver) ~LC-[&$  
{ 30{ gI0jk  
breakWhile = false; ;{6~Bq9  
break; "N#Y gSr  
} 6u%&<")4HP  
} ~J]qP#C  
if(breakWhile) <3 uNl  
break; m {}Lm)M  
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P<-@h1p,  
//count++; +[ZY:ZQ  
//if(count>4) Q{/Ef[(a@  
// siteStop(); ^z\cyT%7t  
} \.S/|  
F"kAkX>3}  
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System.err.println("文件下载结束！"); N>E_%]Ch  
} IGgL7^MF  
catch(Exception e){e.printStackTrace ();} FTldR;}(  
} sos5Y}  
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]@TCk8d$0  
//获得文件长度 (?];VG  
public long getFileSize() BLFdHB.$T  
{ 3$/IC@+  
int nFileLength = -1; tBSW|0  
try{ SfR%s8c`  
URL url = new URL(siteInfoBean.getSSiteURL()); v^PO|Z  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 0}9h]X'  
httpConnection.setRequestProperty("User-Agent","NetFox"); _dg\\c  
}2oc#0  
(%9$!v{3  
int responseCode=httpConnection.getResponseCode(); T{'RV0%   
if(responseCode>=400) P {'b:C  
{ [hsds\  
processErrorCode(responseCode); $Q0n  
return -2; //-2 represent access is error ]'S^]  
} Wl4%GB  
.C(tMF]D,  
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String sHeader; /RF
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}WV:erg`  
w =KPT''!  
for(int i=1;;i++) adw2x pj  
{ 11lsf/IP  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); EV?z`jE9  
//Utility.log(in.readLine()); Xr{v~bf  
sHeader=httpConnection.getHeaderFieldKey(i); 0$njMnB2l  
if(sHeader!=null) gZ5 |UR<  
{ g .\[o@H  
if(sHeader.equals("Content-Length")) <vP=zk  
{ r :dTz  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 'PHl$f*k  
break; fR|A(u#9  
} 4I7>f]=)  
} nP$9CA  
else d'2A,B~_*  
break; y)*RV;^  
} YS ][n_  
} olcDt&xv]  
catch(IOException e){e.printStackTrace ();} j<x_&1  
catch(Exception e){e.printStackTrace ();} P*o9a  
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Utility.log(nFileLength); e;jdqF~v!  
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return nFileLength; `2snz1>!j  
} _j3fAr(V  
@.C2LIb  
>V~E]P%@  
//保存下载信息（文件指针位置） a =QCp4^  
private void write_nPos() $C\BcKlmv  
{ HP=+<]?{G  
try{ z@Y;r=v  
output = new DataOutputStream(new FileOutputStream(tmpFile)); xA
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output.writeInt(nStartPos.length); ]tD]Wx%  
for(int i=0;i<nStartPos.length;i++) KSvE~h[#+  
{ l\mPHA23  
// output.writeLong(nPos); pUTr!fR  
output.writeLong(fileSplitterFetch.nStartPos); +0~YP*I`/  
output.writeLong(fileSplitterFetch.nEndPos); :>*7=q=  
} PdCEUh\>y  
output.close(); Ib`XT0k  
} ]3gSQ7  
catch(IOException e){e.printStackTrace ();} E3i4=!Y  
catch(Exception e){e.printStackTrace ();} dscgj5b1~  
} +H.`MZ=  
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//读取保存的下载信息（文件指针位置） ~`/V(r;o  
private void read_nPos() R@0R`Zs  
{ /mMV{[  
try{ 1,~D4lD|  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); KP"+e:a%  
int nCount = input.readInt(); SIllU  
nStartPos = new long[nCount]; Th%zn2R B  
nEndPos = new long[nCount]; R=dC4;  
for(int i=0;i<nStartPos.length;i++) GmG5[?)  
{ nu^436MSOa  
nStartPos = input.readLong(); =I4lL]>  
nEndPos = input.readLong(); >0gW4!7Y  
} [e q&C_|D  
input.close(); ),)lzN%!  
} @,}UWU  
catch(IOException e){e.printStackTrace ();} cR{#V1Z  
catch(Exception e){e.printStackTrace ();} S3#>9k;p  
} : +u]S2u{  
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private void processErrorCode(int nErrorCode) H.;Q+A,8^  
{
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System.err.println("Error Code : " + nErrorCode); LscGTs,  
} O2+6st  
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.d*8C,  
//停止文件下载 us.~G  
public void siteStop() RNL9>7xV  
{ Y@v>FlqI{  
bStop = true; ;|RTx  
for(int i=0;i<nStartPos.length;i++) .X&9Q9T=#  
fileSplitterFetch.splitterStop(); {_}I!`opr$  

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} b$7 +;I;  
} @ZJS&23E  
//负责部分文件的抓取 'R)Tn!6  
**FileSplitterFetch.java [;N'=]`  
*/ yu|>t4#GT  
package NetFox; zCA2X !7F  
m'U0'}Ld};  
y7{?Ip4[  
import java.io.*; ;"I^ZFYX  
import java.net.*; @iiT
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public class FileSplitterFetch extends Thread { TpaInXR  
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String sURL; //File URL s.rm7r@#  
long nStartPos; //File Snippet Start Position A,]h),b  
long nEndPos; //File Snippet End Position V#HuIgf-  
int nThreadID; //Thread's ID Sz~OX6L  
boolean bDownOver = false; //Downing is over :s,Z<^5a)g  
boolean bStop = false; //Stop identical [^)g%|W  
FileAccessI fileAccessI = null; //File Access interface zA 3_Lx!  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 4*L_)z&4;  
{ (Z*!#}z`  
this.sURL = sURL; +vH4MwG$.&  
this.nStartPos = nStart; gi8FHSU|G  
this.nEndPos = nEnd; '91/md5  
nThreadID = id; ?[AD=rUC  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 /z!%d%"  
} w]H->B29C  
:/#rZPPF  
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public void run() XX@ZQcN  
{ Y73C5.dNcE  
while(nStartPos < nEndPos && !bStop) do%&m]#;  
{ |>Vb9:q9Po  
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try{ eDMO]5}Ht  
URL url = new URL(sURL); 6<
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); . vV|hSc  
httpConnection.setRequestProperty("User-Agent","NetFox"); \G[$:nS  
String sProperty = "bytes="+nStartPos+"-"; q'DW~!>qX  
httpConnection.setRequestProperty("RANGE",sProperty); M7T5 ~/4  
Utility.log(sProperty); bsX[UF
  
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ZH8,KY"  
InputStream input = httpConnection.getInputStream(); DF= *_,2/  
//logResponseHead(httpConnection); >
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byte[] b = new byte[1024]; w}KkvP^  
int nRead; Oz95  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Nc`L;CP  
{ %Zi} MPx  
nStartPos += fileAccessI.write(b,0,nRead); +rd+0 `}C  
//if(nThreadID == 1) ]/Pn EU[  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); WJ#[LF!e  
} siI;"?  
A&VG~r$  
*pq\MiD/  
Utility.log("Thread " + nThreadID + " is over!"); \dVO
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bDownOver = true; HtFDlvdy]  
//nPos = fileAccessI.write (b,0,nRead); :> '+"M2r  
} icgfB-1|i  
catch(Exception e){e.printStackTrace ();} uFE)17E  
} U6K|fYN`  
} Vksuu@cch  
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aUp g u"
 
//打印回应的头信息 r@V!,k#S  
public void logResponseHead(HttpURLConnection con) vN:Ng  
{ Y4-t7UlS;  
for(int i=1;;i++) d=(mw_-
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{ ^[[P*NX3  
String header=con.getHeaderFieldKey(i); K0~rN.C!0  
if(header!=null) Tk
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//responseHeaders.put(header,httpConnection.getHeaderField(header)); DQ3<$0  
Utility.log(header+" : "+con.getHeaderField(header)); ~$'awY  
else N7"W{"3D  
break; Vr}'.\$  
} 3`g^  
} )5,v!X)  
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public void splitterStop() c{|p.hd  
{ m0wDX*Qn  
bStop = true; la!~\wpa  
} G{}VPcrbC  
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V gWRW7Se  
} 1}x%%RD_  
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+(Ae4{z"1+  
/* K+eM   
**FileAccess.java 4(+PD&_J  
*//文件访问(定位，写) Z@HEj_n  
package NetFox; q V=!ORuj  
import java.io.*; vh^VxS  
(.:e,l{U%  
XFl6M~ c  
public class FileAccessI implements Serializable{ 7!1S)dup  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ?<!|  
RandomAccessFile oSavedFile; wk^B"+Uhy  
long nPos; 6k%f  
HMXE$d=[  
*dQSw)R  
public FileAccessI() throws IOException Gc?a+T  
{ z{ dEC %  
this("",0); )~>YH*g  
} "oyo#-5z  
yi[x}ffdE  
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public FileAccessI(String sName,long nPos) throws IOException )%TmAaj9d  
{
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oSavedFile = new RandomAccessFile(sName,"rw"); }MySaL>  
this.nPos = nPos; W?&%x(6M  
oSavedFile.seek(nPos); k$VlfQ'+  
} 4g/d
P^  
h[ ZN+M  
Py<}S-:  
public synchronized int write(byte[] b,int nStart,int nLen) u8^lB7!e/  
{ T{"(\X$  
int n = -1; BT$_@%ea&  
try{ ?dTD\)%A  
oSavedFile.write(b,nStart,nLen);
rv;3~'V  
n = nLen; y =@N|f!  
} 7<4qQ.deE  
catch(IOException e) )b)zm2;  
{ \8tsDG(1 '  
e.printStackTrace (); +ZYn? #IQ  
} UiWg<_<t  
3|7QUld  
]:;&1h3'7  
return n; AA_%<zK  
} ]9-\~Mwh  
M|-)GvR$J  
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} 2%1hdA<  
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/* & kIFcd@  
**SiteInfoBean.java y(Td/rY.  
*/ 6*?F@D2&  
package NetFox; 0(Ij%Wi,  
i4Jc.8^9$  

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public class SiteInfoBean { =41xkAMnk  
X]=t>
 
!k%#R4*>  
private String sSiteURL; //Site's URL )"LJ hLg  
private String sFilePath; //Saved File's Path ijcm2FJcG  
private String sFileName; //Saved File's Name n%-0V>  
private int nSplitter; //Count of Splited Downloading File g`^x@rj`E  
$M#>9QHhc  
0c&+|>!  
public SiteInfoBean() l2d{ 73h  
{//nSplitter的缺省值为5 d _ e WcI  
//default value of nSplitter is 5 wzaV;ac4K  
this("","","",5); *"kM{*3:v  
} hph4`{T  
\jA~9  
>7r!~+B"9'  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) #g=XUZ/"  
{ Q&&@v4L  
sSiteURL= sURL; *VeRVaBl  
sFilePath = sPath; g>sSS8RO  
sFileName = sName; ^.G$Q#y,  
this.nSplitter = nSpiltter; *A< 5*Db:F  
fnY.ao1-s[  
DMS!a$4  
} ]9XDS[<2`  
_
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/bEAK-  
public String getSSiteURL() fh{`Mz,o  
{ 2oU_2P  
return sSiteURL; 9cgUT@a  
} ;
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/>Nt[o[r  
fV:83|eQ  
public void setSSiteURL(String value) ^(<f/C)i  
{ iUwzs&frd  
sSiteURL = value; S$k&vc(0  
} Wf<LR3  
bfO=;S
]b!  
{U1m.30n  
public String getSFilePath() kl,3IKHa  
{ nd(S3rct&  
return sFilePath; ~4"dweu?  
} m3ff;,  
<1pEwI~  
J=L5=G7(  
public void setSFilePath(String value) B;WCTMy}  
{ 66 Tpi![  
sFilePath = value; iCyfOh  
} v@Ox:wl>  
6r_)sHf  
LF7SS;&~f  
public String getSFileName() Ve=b16H  
{ Df#l8YK#  
return sFileName; &[SC|=U'M  
} MW{8VH6+  
QM]YJr3rE  
4OX^(  
public void setSFileName(String value) `lPfb[b  
{ |)81
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sFileName = value; D6^6}1WI  
} VD:/PL  
\;-|-8Q  
C-[1iW'  
public int getNSplitter() qw8Rlws%  
{ $g7<Y*t[  
return nSplitter; ]:f%l mEy  
} gNhQD*+>{  
LK"69Qx?5q  
UDni]P!E  
public void setNSplitter(int nCount) p$>l7?h  
{ Q&V;(L62!  
nSplitter = nCount; A9JdU&  
} /=, nGk>  
} kwA$Z!Rn  
%#}Zy   
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/* O<\@~U  
**Utility.java h@h!,;  
*/ V_:&S2j  
package NetFox; r4f~z$QK  
)Beiu*  
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public class Utility { ${)b[22":  
,=:D  
]cN1c}  
public Utility() 6DWgl$[[  
{ BCcjK6'  
eN~=*Mn(za  
pBPl6%C.X-  
} U3:j'Su4H?  
e*n@j  
//线程睡眠 orvp*F{7[H  
public static void sleep(int nSecond) Y5d\d\e/  
{  65m"J'  
try{ EU/8=JA1  
Thread.sleep(nSecond); W"3ph6[eW  
} i2^>vYCsl  
catch(Exception e) Ip]KPrwp  
{ Pco'l#:  
e.printStackTrace (); Jdp3nzM^^@  
} 7`hP?a=  
} ;
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2,P^n4~A?w  
//日志 K!]/(V(}  
public static void log(String sMsg) hDq`Z$_+KX  
{ @Pz
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System.err.println(sMsg); ED& `_h7?  
} I15{)o(8$  
Y7[jqb1D  
F
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public static void log(int sMsg) 4X(H;  
{ wuJ4kW$  
System.err.println(sMsg); [=]4-q6UN  
} +XYE{E5  
} '-/xyAzS  
#`X?=/q  
KFkoS0M5|  
/* G<^{&E+=  
**TestMethod.java X/M4!L}\  
*/ LAe6`foW/  
package NetFox; Clb@$,  
}k G9!sf  
_Z,\Vw:\F  
public class TestMethod { +V^;.P</  
\A6B,|@  
y[_Q-   
public TestMethod() ~PahoRS  
{ ///xx/weblogic60b2_win.exe 84pFc;<  
try{ W#C*5@8  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); )sp4Ie  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ^J8lBLqe  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 'xg Lt(  
fileFetch.start(); j;iAD:nf  
} =-lb)Z"d  
catch(Exception e){e.printStackTrace ();} +|89>}w4  
#7YY<) xt}  
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} a1y-3z  
cFnDmtI:  
&wE%<"aRAl  
public static void main(String[] args) c[1oww  
{ BC<^a )D=  
new TestMethod(); O,h;hQZ  
} f|lU6EkU  
} zY!j:FT1HY  
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