http断点续传简单实现（java)

/* s"r*YlSp"  
**SiteFileFetch.java YJT&{jYi  
*/ ~:s>aQ`!  
package NetFox; 12b(A+M   
import java.io.*; r@H /kD  
import java.net.*; "#2a8#  
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public class SiteFileFetch extends Thread { 8V`WO6*  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 65J
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long[] nStartPos; //开始位置 V]lLw)  
long[] nEndPos; //结束位置 KQ% GIz x  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 {k TEHe  
long nFileLength; //文件长度 p>v$FiV2N  
boolean bFirst = true; //是否第一次取文件 3M[!N  
boolean bStop = false; //停止标志 s+$ Q}|?u  
File tmpFile; //文件下载的临时信息 dy%;W%   
DataOutputStream output; //输出到文件的输出流 ; F"g$_D0  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） B"1c  
public SiteFileFetch(SiteInfoBean bean) throws IOException Bq%Jh  
{ |4;Fd9q^m  
siteInfoBean = bean; ,~N/- 5  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); IL#"~D?
  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); hF~n)oQ  
if(tmpFile.exists ()) `ts$(u.w  
{ k8&;lgO'  
bFirst = false; k<CJ{u0<  
read_nPos(); 7rc0yB  
} X9W@&zQ  
else X!TpYUZ'  
{ Tztu}t]N  
nStartPos = new long[bean.getNSplitter()]; [ )Iv^ U9  
nEndPos = new long[bean.getNSplitter()]; Hw}Xbp[y  
} ?jv
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} ohGJ1  
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public void run() dd%6t  
{ /=nJRC3.  
//获得文件长度 }c,}V  
//分割文件 24 'J  
//实例FileSplitterFetch [.7d<oY  
//启动FileSplitterFetch线程 xX&+WR  
//等待子线程返回 %HhnSi1K  
try{ [Gb. JO}X  
if(bFirst) \
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{ ]vUwG--*  
nFileLength = getFileSize(); cKca;SNql1  
if(nFileLength == -1) r,73C/*&/  
{ RLjc&WhzXu  
System.err.println("File Length is not known!"); *SJ_z(CZm  
} ,aZ[R27rpL  
else if(nFileLength == -2) >C>.\  
{ gV's=c
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System.err.println("File is not access!"); s%7t"-=&  
} Uiw2oi&_  
else Cw3a0u  
{ ?=sDM& '  
for(int i=0;i<nStartPos.length;i++) J/y83@  
{ O3,jg|,  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); yLvDMPj  
} #CTE-W"|HE  
for(int i=0;i<nEndPos.length-1;i++) UERLtSQ  
{ JX;<F~{.  
nEndPos = nStartPos[i+1]; 0*3R=7_},o  
} /l~p=PK  
nEndPos[nEndPos.length-1] = nFileLength; Cv.C;H  
} lfow1WRF  
} *w`sM%]Rq  
Z"xvh81P  
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//启动子线程 vm8eZG|  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; A:%`wX}  
for(int i=0;i<nStartPos.length;i++) -l*|M(
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{ &jJL"gq"  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 6Pl<'3&  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), y'q$|  
nStartPos,nEndPos,i); AO4U}?  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 1v27;Q<+Q  
fileSplitterFetch.start(); k(nW#*N_  
} `Y$4 H,8L  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), l_d5oAh   
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); _ ]ipajT  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ",  +SU8 +w  
nEndPos = " + nFileLength); 7&)bJ@1U  
// fileSplitterFetch[nPos.length-1].start(); eu-*?]&Di  
[q[Y~1o/&H  
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//等待子线程结束 BL}\D;+t  
//int count = 0; 97*p+T<yp  
//是否结束while循环 &DX! f  
boolean breakWhile = false; ~TD0zAA&  
<)H9V-5aZ  
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while(!bStop) 0v?"tOT!  
{ %J?xRv!  
write_nPos(); Ffz,J6b  
Utility.sleep(500); JX;G
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breakWhile = true; FDs>m #e  
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for(int i=0;i<nStartPos.length;i++) n b?lTX~  
{ .|70;  
if(!fileSplitterFetch.bDownOver) |0b`fOS  
{ i[3'ec3  
breakWhile = false; [}=B8#Jl-C  
break; ![=yi tB  
} !*N@ZL&X  
} Bnxm HGP#&  
if(breakWhile) F^;ez/Gl  
break; V b?oJhR  
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//count++; m<Dy<((_I  
//if(count>4) [RhO$c$[\  
// siteStop(); |/{=ww8|  
} SY\ gXO8k  
",; H`V  

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System.err.println("文件下载结束！"); :DNY7TvZ  
} 0S!K{xyR  
catch(Exception e){e.printStackTrace ();} ,#9PxwrO  
} $%#!bV  
(uE!+2C  
@
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//获得文件长度 S4z;7z(8+  
public long getFileSize() uy$e?{Jf  
{ YU'E@t5  
int nFileLength = -1; 3F2w-+L  
try{ Wh*uaad7  
URL url = new URL(siteInfoBean.getSSiteURL()); ?CPahU  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); bROLOf4S  
httpConnection.setRequestProperty("User-Agent","NetFox"); {JMVV_}n  
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]N?kG`[  
int responseCode=httpConnection.getResponseCode(); ^u ~Q/4  
if(responseCode>=400) "+G8d'%YV  
{ 9WyhZoPD*  
processErrorCode(responseCode); !Wnb|=j  
return -2; //-2 represent access is error &
Ok)
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} lRFYx?y  
>|UOz&  
j A%u 5V  
String sHeader; 2FJ*f/  
3f{3NzN  
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for(int i=1;;i++) XW]tnrs  
{ 2P0*NQ  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); s;Q!X ?Q  
//Utility.log(in.readLine()); @\#td5'  
sHeader=httpConnection.getHeaderFieldKey(i); /PIcqg  
if(sHeader!=null) Gyc]?m  
{ (f"4,b^]  
if(sHeader.equals("Content-Length")) (*iHf"=\  
{ [{,1=AB  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); `[ir}+S  
break; MQ6KN(?\ZL  
} MQ8J<A Pf-  
} wnC81$1l~  
else $xN|5;+  
break; fNFY$:4X  
} &D*b|ilvc  
} C~/a-  
catch(IOException e){e.printStackTrace ();} wf<M)Rs|  
catch(Exception e){e.printStackTrace ();} }BP;1y6-r  
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Utility.log(nFileLength); H/M@t\$Dc  
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return nFileLength; 5=ryDrx  
} 6=Otq=WH  
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//保存下载信息（文件指针位置） `;egv*!P  
private void write_nPos() 4o[{>gW  
{ "^GGac.  
try{ \'O"~W  
output = new DataOutputStream(new FileOutputStream(tmpFile)); )Pv%#P-<  
output.writeInt(nStartPos.length); o`-msz  
for(int i=0;i<nStartPos.length;i++) 6Z"X}L,*  
{ 0o&5]lEe  
// output.writeLong(nPos); $IpccZpA  
output.writeLong(fileSplitterFetch.nStartPos); VI*$em O0  
output.writeLong(fileSplitterFetch.nEndPos); qIT@g"%}t  
} j0q&&9/Jj  
output.close(); CpTjJXb  
} 3u0RKLc\  
catch(IOException e){e.printStackTrace ();} l.M0`Cn-%  
catch(Exception e){e.printStackTrace ();} U 6)#}
 
} h/Y'<:  
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//读取保存的下载信息（文件指针位置） |2A:eI8 ^  
private void read_nPos() dk^~;m#iN  
{ K{+2G&i  
try{ KMax$  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); G 01ON0  
int nCount = input.readInt(); S,8elKH4  
nStartPos = new long[nCount]; &$H!@@09|w  
nEndPos = new long[nCount]; =7UsVn#o  
for(int i=0;i<nStartPos.length;i++) J#83 0r(-  
{ cFXp  
nStartPos = input.readLong(); [dz _R  
nEndPos = input.readLong(); B%68\  
} I7]8Y=xf  
input.close(); ftSW (og  
} v`T c}c '  
catch(IOException e){e.printStackTrace ();} Zv{'MIv&v  
catch(Exception e){e.printStackTrace ();} wC'Szni  
} -mh3DhJ,  
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private void processErrorCode(int nErrorCode) {P-):  
{ ~&uHbTq  
System.err.println("Error Code : " + nErrorCode); Dw"\/p:-3  
} 7zj{wp!  
nO-#Q=H,  
h{qgEIk&  
//停止文件下载 +b6v!7_  
public void siteStop() yB!dp;gM{  
{ |I=T@1_D  
bStop = true; -yg7;ff  
for(int i=0;i<nStartPos.length;i++) `WS&rmq&'  
fileSplitterFetch.splitterStop(); o4WDh@d5S  
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/gas2k==^  
} \OoWo  
} %a7$QF]  
//负责部分文件的抓取 e|r`/:M  
**FileSplitterFetch.java x?<FJ"8"k  
*/ mR)wX 6  
package NetFox; vP,n(reM  
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*n!J=yS  
import java.io.*; _yT Ed"$  
import java.net.*; '5tCz9}Y  
\b>]8Un"  
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public class FileSplitterFetch extends Thread { Dt1jW  
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String sURL; //File URL 2`-Bs  
long nStartPos; //File Snippet Start Position ,]D,P  
long nEndPos; //File Snippet End Position w!XD/jN  
int nThreadID; //Thread's ID QZ8IV>  
boolean bDownOver = false; //Downing is over -Qe'Y
By:  
boolean bStop = false; //Stop identical Uw:"n]G]D?  
FileAccessI fileAccessI = null; //File Access interface M3au{6y  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException hqdDm  
{ 1 -b_~DF  
this.sURL = sURL; %l%HHT  
this.nStartPos = nStart; K)P%;X  
this.nEndPos = nEnd; !@"OB~  
nThreadID = id; rZpXPI  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 QsW/X0YBv  
} %}T6]S)%u  
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public void run() ajpXL  
{ 8?C5L8)  
while(nStartPos < nEndPos && !bStop) 47B&s   
{ 5-A\9UC*@  
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try{ *K;~!P  
URL url = new URL(sURL); `0R./|bv\I  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); E(|>Ddv B&  
httpConnection.setRequestProperty("User-Agent","NetFox"); "Yy n/  
String sProperty = "bytes="+nStartPos+"-"; t`QENXA}  
httpConnection.setRequestProperty("RANGE",sProperty); Xnh8e  
Utility.log(sProperty); ##ANrG l  
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InputStream input = httpConnection.getInputStream(); T^q 0'#/  
//logResponseHead(httpConnection);
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byte[] b = new byte[1024]; p b,. r  
int nRead; :v 4]D4\o  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) y
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{ XX~,>Q}H=  
nStartPos += fileAccessI.write(b,0,nRead); ch]29  
//if(nThreadID == 1) wyG;8I  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); :Tq~8!s  
} [/ZO q  
:hA#m[  
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Utility.log("Thread " + nThreadID + " is over!"); Q@HV- (A  
bDownOver = true; c[e}w+uB  
//nPos = fileAccessI.write (b,0,nRead); 1:wQ.T  
} i6N',&jFU  
catch(Exception e){e.printStackTrace ();} tMe~vq[  
} QSj]ZA  
} xezcAwW  
\j.:3Xr  
@ .KGfNu  
//打印回应的头信息 FPTK`Gd0  
public void logResponseHead(HttpURLConnection con) |K~Nw&rZ]  
{ 2TuU2 f.  
for(int i=1;;i++) y> (w\K9W  
{ 8>%hz$no=  
String header=con.getHeaderFieldKey(i); (iGTACoF  
if(header!=null) ~{gqsuCCL  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); y?!"6t7&  
Utility.log(header+" : "+con.getHeaderField(header)); ET >](l9  
else uIrG*K  
break; |&jXp%4T  
} w=@Dv  
}  C.QO#b  
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public void splitterStop() ^W@5TkkBQq  
{ "h ^Z  
bStop = true; )CyS#j#=  
} 2BobH_H  
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} /Q )\+  
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/* (9h`3#  
**FileAccess.java GH xp7H  
*//文件访问(定位，写) BPHW}F]X  
package NetFox; yppo6HGD  
import java.io.*; Xm2'6f,  
rN{ c7/|  
kNL\m[W8$  
public class FileAccessI implements Serializable{ iyog`s c  
Xry47a )  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 RFH0  
RandomAccessFile oSavedFile; {BHO/q3  
long nPos; G#1GXFDO{  
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public FileAccessI() throws IOException 8.~kK<)!  
{ yOKI*.}  
this("",0); abEmRJTmW  
} 1i] ^{;]  
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public FileAccessI(String sName,long nPos) throws IOException w`=\5Oa.G  
{ MJrR[h]  
oSavedFile = new RandomAccessFile(sName,"rw"); 2:=  
this.nPos = nPos; <^uBoKB/f  
oSavedFile.seek(nPos); EZ`{
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} o8vug$=Z  
e0 T\tc  
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public synchronized int write(byte[] b,int nStart,int nLen) v9->nVc-  
{ zv"Z DRW  
int n = -1; x$%!U[!3  
try{ \^%}M!tan  
oSavedFile.write(b,nStart,nLen); :,I:usW"  
n = nLen; E+JqWR5  
} V2G6Kw9gt  
catch(IOException e) 4a]P7fx-  
{ SZ$Kz n  
e.printStackTrace (); IaXeRq?<  
} OBAi2Vw  
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return n; veh<R]U  
} "w.3Q96r  
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} ;d9QAN&0}  
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#N cK X  
/* C73kJa  
**SiteInfoBean.java 4_cqT/  
*/ >oe]$r  
package NetFox; IobD3:D8
W  
abLnI =W`  
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public class SiteInfoBean { I(0~n,=j  
u-5{U-^_  
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private String sSiteURL; //Site's URL xlg9TvvI  
private String sFilePath; //Saved File's Path & 9 ?\b7  
private String sFileName; //Saved File's Name 3
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private int nSplitter; //Count of Splited Downloading File t1y4 7fX6  
~`:L?Jkb6H  
$H>W|9Kg,  
public SiteInfoBean() s}% M4  
{//nSplitter的缺省值为5 X*Prll(  
//default value of nSplitter is 5 Gk /fBs  
this("","","",5); OH(waKq2I  
} s+?zL~t  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) p2$P:!Y)  
{ 3x'|]Ns  
sSiteURL= sURL; BKjS ,2C  
sFilePath = sPath; _t #k,;  
sFileName = sName; SJ>vwmA4  
this.nSplitter = nSpiltter; ~AT'[(6  
(c &mCJN  
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} <;Zmjeb+#  
DG:Z=LuJr  
czRFMYE  
public String getSSiteURL() 76h ,]xi  
{ =mp;.k95  
return sSiteURL; zsyIV!(  
} SmSH2m-  
e [mm  
'Xq|Kf (  
public void setSSiteURL(String value) FZslv"F  
{ <s<n  
sSiteURL = value; KEjWRwN  
} F%D.zvKN  
XXn67sF/  
X
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public String getSFilePath() 54R#W:t  
{ '^~{@~ ;%L  
return sFilePath; 65$+{s  
} nwRc%C``UK  
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J
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public void setSFilePath(String value) A1>OY^p3%  
{ 
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sFilePath = value; *@=/qkaJaI  
} ~^fZx5  
XXcl{1Kp!@  
Jgd'1'FOs  
public String getSFileName() co|aC!7  
{ ywm8N%]v  
return sFileName; }"%?et(  
} !1H# 6  
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public void setSFileName(String value) .p]RKS=(:  
{ lKp"xcAD  
sFileName = value; >T3-  
} ZWU)\}}_R  
qCpp6~]Um  
VfC<WVYiZ  
public int getNSplitter() {|_M #w~&  
{ (
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return nSplitter; jaMjZp;{(  
} Pz|>"'  
oiT[de\S  
{e9@-  
public void setNSplitter(int nCount) BmMGx8P  
{ ujq=F  
nSplitter = nCount; O/a4]r+_  
} #;qdY[v  
} >j(_[z|v3  
BsqP?/  
[-k  
/* |w1Bq  
**Utility.java xPk8$1meZM  
*/ #Z`q+@@]A  
package NetFox; mD0f<gJ1  
)c83/= <v  
," Wr"  
public class Utility { >WQMqQ^t@  
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&(G\[RWp\  
public Utility() l7259Ro~  
{ OgQV;at  
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zRl3KjET  
} ;R5`"`  

J^nBdofP  
//线程睡眠 W*4-.*U8a  
public static void sleep(int nSecond) YEs&  
{ @+
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try{ gA5/,wDO  
Thread.sleep(nSecond); WJndoB.f[2  
} nntuLuW  
catch(Exception e) BNl5!X^{  
{ ]Svt`0|}  
e.printStackTrace (); ?m=N]!n  
} :O?MSS;~  
} =wHVsdNCN  
wd^':  
//日志 *{@Nq=fE  
public static void log(String sMsg) TJpD{p}  
{ Ic:(Gi- %  
System.err.println(sMsg); wj<6kG  
} [f-?ymmT  
}[};IqVaK  
Ae^~Cz1qz  
public static void log(int sMsg) '&R2U_  
{ dulI&_x  
System.err.println(sMsg);
eRstD>r  
} }wjw:M  
} x{8xW0  
%2/EaaR  
"f2$w  
/* Lpz>>}  
**TestMethod.java Yty/3T3)e  
*/ 4 Y9`IgQ  
package NetFox; 4*#18<u5  
\*y-g@-{W$  
nH'e?>x~e  
public class TestMethod { K.nHii   
Y>T-af49  
l0w]`EE  
public TestMethod() sA/D]W.P  
{ ///xx/weblogic60b2_win.exe vHc%z$-d  
try{ #PW9:_BE  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); f4b/NG|  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); _QE qk@ql  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ")5":V~fN  
fileFetch.start(); 9C9oUtS  
} I)6+6pm  
catch(Exception e){e.printStackTrace ();} z`}qkbvi  
|?xN\O^#}  
<CiSK!  
} Xp% v.M  
EhvX)s  
NiK4d{E&  
public static void main(String[] args) XS{Qnx_#  
{ "ycJ:Xv49  
new TestMethod(); t+G#{n  
} fk>aqm7D!  
} RnE4<Cy  
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