http断点续传简单实现（java)

/* Qy9_tvq X  
**SiteFileFetch.java h>V6}(~;.  
*/ 4Y?fbb<  
package NetFox; &~eCDlX/  
import java.io.*; [lIX&!T"  
import java.net.*; )y]Dmm  
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o+x%q<e;c  
public class SiteFileFetch extends Thread { pS8\B  
E#P#{_BR^  
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SiteInfoBean siteInfoBean = null; //文件信息Bean }h1BAKg  
long[] nStartPos; //开始位置 {eU>E/SQ  
long[] nEndPos; //结束位置 !Mw/j`*  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ,xU#uyB  
long nFileLength; //文件长度 S(3h{Y"#  
boolean bFirst = true; //是否第一次取文件 E0qJ.v  
boolean bStop = false; //停止标志 ir'<H<t2  
File tmpFile; //文件下载的临时信息 &7'=t6  
DataOutputStream output; //输出到文件的输出流 F+Kju2  
7s%D(;W_Mo  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 3z0Bg  
public SiteFileFetch(SiteInfoBean bean) throws IOException \2u7>fU!  
{ npeL1zO-$  
siteInfoBean = bean; O$z"`'&j#  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); d%}?%VH  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); $/^Y(0  
if(tmpFile.exists ()) K cex%.  
{ PoZ$3V$(Lz  
bFirst = false; M"]?'TMfXc  
read_nPos(); %x#S?GMV<  
} Ip{hg,>  
else Yjo$vQi  
{ pej-W/R&  
nStartPos = new long[bean.getNSplitter()]; dZ"}wKbO  
nEndPos = new long[bean.getNSplitter()]; '[6]W)f  
} 4r;le5@  
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} mmwc'-jU:  
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public void run() lLVD`)  
{ R)d_0Ng  
//获得文件长度 R:P),
 
//分割文件 4qDa:D"5  
//实例FileSplitterFetch g&RhPrtl  
//启动FileSplitterFetch线程 v$`3}<3-  
//等待子线程返回 [W$x5|Z}Q  
try{ E_&;.hw  
if(bFirst) ?p6@uM\Q7  
{ atZNX1LD[/  
nFileLength = getFileSize(); h_X'O3r  
if(nFileLength == -1) no\G >#  
{ 1V5N)ty  
System.err.println("File Length is not known!"); [*K9V/  
} %dw0\:P?Q  
else if(nFileLength == -2) 8F\'?7  
{ D7R;IA-w  
System.err.println("File is not access!"); %A 5s?J?  
} L?N:4/0;!  
else <> HI(6\@Z  
{ D0\*WK$  
for(int i=0;i<nStartPos.length;i++) 7.{+8#~nV  
{ F6{ O  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); _0[s]  
} QBmARQ  
for(int i=0;i<nEndPos.length-1;i++) aIT0t0.  
{ q8_E_s-U,  
nEndPos = nStartPos[i+1]; p8]XNe  
} 6I~M8Lo;  
nEndPos[nEndPos.length-1] = nFileLength; NWwKp?  
} `-s]dq  
} |@rf#,hTDp  
XwIHIG}  
PtPx(R3  
//启动子线程 xxGQXW  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; E0i!|H  
for(int i=0;i<nStartPos.length;i++) EP4?+"Z  
{ g:^Hex?Yfd  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Cjt].XR@  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), R8.@5g_  
nStartPos,nEndPos,i); c~M'O26bW  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Y}}1]}VIK  
fileSplitterFetch.start(); ER`;0#3[9u  
} H(?+-72KX  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), (eT9N_W  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 5!i\
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// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", =f=>buD  
nEndPos = " + nFileLength); {JQV~rfh`  
// fileSplitterFetch[nPos.length-1].start(); m,5m'9dj  
abVEi[nP  
X.e4pLwGK  
//等待子线程结束 uf)!SxT  
//int count = 0; Ayw {I#"  
//是否结束while循环 +IGSOWL  
boolean breakWhile = false; &mJm'Ks  
;[C_h
o  
y
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while(!bStop) aB&a#^5CI  
{ gW G>}M@  
write_nPos(); N+UBXhh
  
Utility.sleep(500);
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breakWhile = true; )CH\]>-FO  
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for(int i=0;i<nStartPos.length;i++) j%S} T)pX  
{ &x.5TDB>%  
if(!fileSplitterFetch.bDownOver) o -x=/b  
{ ^6UE/4x!y  
breakWhile = false; pmUC4=&e  
break; ],<pZ1V;  
} y
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} 9j5k=IXg#a  
if(breakWhile) Y>i Qp/k:  
break; KWVl7Kw#e  
=
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//count++; Wsw/ D  
//if(count>4) UWgPQ%}  
// siteStop(); d~CZ9h  
} :Mu]*N  
['c*<f" D2  
7?Twhs.O  
System.err.println("文件下载结束！"); GKXd"8z]  
} od/Q"5t[p  
catch(Exception e){e.printStackTrace ();} UnTvot6~  
} c=B!\J<1  
}1Hy[4B(k\  
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//获得文件长度 I~M@v59C  
public long getFileSize() ?DM!=.]  
{ AbMf8$$3SH  
int nFileLength = -1; K}dvXO@=|c  
try{ D<4cpH  
URL url = new URL(siteInfoBean.getSSiteURL()); .L
3D]  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); v00w GOpW  
httpConnection.setRequestProperty("User-Agent","NetFox"); lt C  
>{h/4T@  
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int responseCode=httpConnection.getResponseCode(); 3jM+j_nR  
if(responseCode>=400) $Ehe8,=fj  
{ ]EvK
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processErrorCode(responseCode); F$,i_7Z&6  
return -2; //-2 represent access is error ibuoq X`  
} dJ,,yA*  
=W'{xG}  
4^w`]m  
String sHeader; QL@}hw.F  
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for(int i=1;;i++) $gcC}tX  
{ YLNJ4nE  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); U'xmn$O  
//Utility.log(in.readLine()); L8$+%Gvo  
sHeader=httpConnection.getHeaderFieldKey(i); D0p>Q^w  
if(sHeader!=null) u85Uy yN  
{ X./7b{Pax  
if(sHeader.equals("Content-Length")) &Y8S! W@4  
{ d+6-ten  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); G4K3qD#+H  
break; WaDdZIz4  
} =(as{,j  
} D"s ]dQ$r  
else }C{wGK+o[  
break; -]Q6Ril  
} :8Ql(I  
} I#:4H2H6  
catch(IOException e){e.printStackTrace ();} Z'\{hL S  
catch(Exception e){e.printStackTrace ();} `< cn  
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Utility.log(nFileLength); v?#W/].C+  
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return nFileLength; 5tu 4uYp;  
} sxn^1|O;m  
qa)Qf,`  
{b]V e/\  
//保存下载信息（文件指针位置） l 1Ns~  
private void write_nPos() A:Kit_A  
{ r=^?  
try{ J*r%b+  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Xp_G9I,+  
output.writeInt(nStartPos.length); %D
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for(int i=0;i<nStartPos.length;i++) {wVJv1*l  
{ JQ"w{O  
// output.writeLong(nPos); L=-v>YL+  
output.writeLong(fileSplitterFetch.nStartPos); "s rRlu
 
output.writeLong(fileSplitterFetch.nEndPos); |7E1yu  
} jf~-;2  
output.close(); NR0fxh  
} 8\_YP3  
catch(IOException e){e.printStackTrace ();} @xPWR=Lb  
catch(Exception e){e.printStackTrace ();} <lHVch"(^$  
} <(dg^;  
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//读取保存的下载信息（文件指针位置） l]__!X  
private void read_nPos() u
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{ bZzB\FB~  
try{ _(J/$D  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); )Vnqz lI5  
int nCount = input.readInt(); 9/I|oh_ G  
nStartPos = new long[nCount]; w4\g]\  
nEndPos = new long[nCount]; T!Eyq,]  
for(int i=0;i<nStartPos.length;i++) Pa\"l'!>^  
{ .7M:AS>  
nStartPos = input.readLong(); {G4{4D }  
nEndPos = input.readLong(); t73" d#+  
} M"<B@p]rk:  
input.close(); u8i!Fxu  
} QwgP+ M+  
catch(IOException e){e.printStackTrace ();} "1%YtV5R{  
catch(Exception e){e.printStackTrace ();} e?)ic\K  
} 6]5e(J{Fz  
+*ZF52hy|  
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private void processErrorCode(int nErrorCode) u:s[6T0  
{ ya0D50m  
System.err.println("Error Code : " + nErrorCode); jxNnrIA  
} c*HWH$kB  
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@Xj6h!"R  
//停止文件下载 ;dE'# Kb  
public void siteStop() ;ax%H @o  
{ Dt\rMSjZ9  
bStop = true; "YePd*W  
for(int i=0;i<nStartPos.length;i++) ^OnZ9?C{R  
fileSplitterFetch.splitterStop(); &3%V%_  
;7w4BJcq']  
eg Zb)pP  
} 4vb
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} LP-_i}Kq  
//负责部分文件的抓取 i*ErxWzu  
**FileSplitterFetch.java 68-2EWq  
*/ g6~B|?!   
package NetFox; 86<[!ZM  
-"MB(`  
),]XN#jp(u  
import java.io.*; =E10j.r  
import java.net.*; {m7>9{`  
"`&1"*  
@eU5b63jM  
public class FileSplitterFetch extends Thread { nN$aZSb`  
'\I!RAZ  
l.`f^K=8  
String sURL; //File URL kcN#g-0  
long nStartPos; //File Snippet Start Position v3/l=e?u  
long nEndPos; //File Snippet End Position F>/"If#  
int nThreadID; //Thread's ID b'$fr6"O1  
boolean bDownOver = false; //Downing is over q7ubRak  
boolean bStop = false; //Stop identical oVYW'~OID  
FileAccessI fileAccessI = null; //File Access interface )=@SA`J  
S1D=' k]  
<9jN4hV  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 1xzOD@=dI  
{ Nr#" 5<W  
this.sURL = sURL; + tza]r:  
this.nStartPos = nStart; rwSmdJ~  
this.nEndPos = nEnd; hk.Zn.6A'  
nThreadID = id; Ir :y#  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 nb,+!)+  
} ~s4o1^6L  
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public void run() P!K;`4Ika  
{ \GEf,%U<K  
while(nStartPos < nEndPos && !bStop) bfl%yGkd/|  
{ Hm*?<o9mxC  
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try{ |VxO ,[~  
URL url = new URL(sURL); s%l`XW;v  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ?KMGk]
_<  
httpConnection.setRequestProperty("User-Agent","NetFox"); 1sN >U<  
String sProperty = "bytes="+nStartPos+"-"; (D1$&  
httpConnection.setRequestProperty("RANGE",sProperty); t0-)\kXcA  
Utility.log(sProperty); k;c>=B)e  
"{"745H5  
$>=?'wr  
InputStream input = httpConnection.getInputStream(); CZ4Nw]dtR  
//logResponseHead(httpConnection); fA{t\  
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byte[] b = new byte[1024]; E\lel4ai  
int nRead; lbUUf}   
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) U,2H) {l/  
{ 
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nStartPos += fileAccessI.write(b,0,nRead); (+lCh7.  
//if(nThreadID == 1) n0rAO
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// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); '&42E[0P  
} gUtxyW  
L j>HZS$F  
O|I)HpG;  
Utility.log("Thread " + nThreadID + " is over!"); LL"c 9jb4z  
bDownOver = true; Cr#Z.  
//nPos = fileAccessI.write (b,0,nRead); i^2-PKPg{  
} \6WVs>z  
catch(Exception e){e.printStackTrace ();} 5,Hj$v7fe  
} >IFqwh7b  
} :7Jpt3  
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kK&M>)&o#  
//打印回应的头信息 "-afHXED  
public void logResponseHead(HttpURLConnection con) (HD8Mm  
{ uXkc07 r'  
for(int i=1;;i++) F\IJim-Rh  
{ 3tu:Vc.:M  
String header=con.getHeaderFieldKey(i); ilr'<5rq  
if(header!=null) QK0-jYG^  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Oi-= Fp  
Utility.log(header+" : "+con.getHeaderField(header));  A4  
else $-ICTp  
break; [JyhzYf\  
} o~J~-$T{  
} q88;{?T1  
TQ&1!~L*  
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public void splitterStop() <7R+p;y  
{ ayK?\srw  
bStop = true; 9_ru*j\  
} !)-)*T  
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} f<;w1sM\  
-lqsFaW  
{;-wXzv`  
/* 8o%g2 P9.  
**FileAccess.java rGIf/=G^r  
*//文件访问(定位，写) $z48~nu@j  
package NetFox; TkyP_*  
import java.io.*; %=[xc?  
Kd;Iu\4hv  
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public class FileAccessI implements Serializable{ |zCT~#  
4157!w'\y  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 U *K6FWqiB  
RandomAccessFile oSavedFile; VAnP3:  
long nPos; >Sc/E}3  
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KbTd`AIL  
public FileAccessI() throws IOException unD.t  
{ u/ZV35z  
this("",0); 4];<` %  
} ,d`6 {ll  
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public FileAccessI(String sName,long nPos) throws IOException oGvk,mh"(  
{ e~P4>3  
oSavedFile = new RandomAccessFile(sName,"rw"); mIh >8))E  
this.nPos = nPos;  hSgH;k  
oSavedFile.seek(nPos); e]DuV)k&  
} VqL#w<A%  
"J"RH:$v  
H9%[! RF  
public synchronized int write(byte[] b,int nStart,int nLen) cf+EQY  
{ l?<DY$H 0  
int n = -1; 'dvi@Jx  
try{ J|=0 :G  
oSavedFile.write(b,nStart,nLen); 5`\"UC7?%  
n = nLen; /hp [+K  
} dKJ-{LV  
catch(IOException e) Zgw4[GpL  
{ LTWiCI  
e.printStackTrace (); ^Gwpx+  
} &qyXi[vw  
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;FnU[Q`M#L  
return n; C/#?S=w`4  
} aE 2=  
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} y%!zXK`cl]  
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:`B70D8ku  
/* Dn[uzY6  
**SiteInfoBean.java t>}(`0  
*/ VOGx  
package NetFox; z2~\ b3G  
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public class SiteInfoBean { Oj8xc!d'  
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F  
p)Fi{%
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private String sSiteURL; //Site's URL k
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private String sFilePath; //Saved File's Path Av>xgfX  
private String sFileName; //Saved File's Name I_5[-9  
private int nSplitter; //Count of Splited Downloading File }fZ~HqS2w  
P!u0_6  
utU;M*  
public SiteInfoBean() zK>}x=  
{//nSplitter的缺省值为5  h@CP  
//default value of nSplitter is 5 aI
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this("","","",5); Xmw%f[Xl  
} Jp"[`
m  
aNUMF  
p}p}!M|  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) }6"l`$=Ev  
{ 3FG'A[x3O  
sSiteURL= sURL; hdDL92JVg  
sFilePath = sPath; :_[pZ;-@  
sFileName = sName; y*e({fio_  
this.nSplitter = nSpiltter; UetI4`  
)nlFyWXh.  
{[~dI ~  
} #ON
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sL)7MtNwy  
2sYz$ZGC"#  
public String getSSiteURL() :u`gjj$:s  
{ ,wZq~;2  
return sSiteURL; 0@wXE\s  
} 1h3`y  
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sspGB>h8l  
public void setSSiteURL(String value) y7vA[us  
{ 4m!w<c0NL  
sSiteURL = value; H"c2kno9  
} fyEXnmB;  
VE))`?  
v;#0h7qd  
public String getSFilePath() /h 4rW>8D2  
{ B&AF(e (  
return sFilePath; MIY`"h0*  
} -oi@1g@  
.UYhj8  
=g|5VXW5  
public void setSFilePath(String value) !NMiWG4R  
{
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sFilePath = value; VV"w{#XKw  
} Uf9L*Z'6il  
'.]<lh!  
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public String getSFileName() <6&Z5mpm$w  
{ q;.LK8M  
return sFileName; y ~Fi  
} JC#5CCz  
=w7+Yt  
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public void setSFileName(String value) [IgqK5@  
{ w
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sFileName = value; e4FR)d0x  
} p\Fxt1Y@X  
3Xm> 3  
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public int getNSplitter() ;Irn{O  
{ @M6F?;  
return nSplitter; :qj7i(
  
} h0")NBRV&  
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v oO7W"  
public void setNSplitter(int nCount) vCUbbQz  
{ 7n*"9Ai(  
nSplitter = nCount; G
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} "A0y&^4B@  
} Bm;: cmB0e  
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/* Bm 4$  
**Utility.java SPm2I(at7  
*/ <j1r6.E)  
package NetFox; "JE->iD  
%~[@5<p  
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public class Utility { uSv]1m_-]  
H.[nr:  
%<`sDO6Q
?  
public Utility() _k#GjAPM  
{ GK[Hs1/  
JvkTfTE7  
#'n.az=1  
} BS%pS(  
hFnUw26P  
//线程睡眠 )Myx(w"S  
public static void sleep(int nSecond) yd[4l%G(zS  
{ IY|`$sHb  
try{ E=91k.  
Thread.sleep(nSecond); 6{I6'+K~  
} 0"Zxbgu)  
catch(Exception e) 4'td6F  
{ DB}v..  
e.printStackTrace (); 7~);,#[ky  
} 5}a.<  
} sFHqLG{/  
~[=d{M!$W  
//日志 ={51fr/C%  
public static void log(String sMsg) v`S ;.iD  
{ r;p@T8k  
System.err.println(sMsg); (}s& 84!  
} )G-u;1r
d  
ZQn>+c2%!  
6n
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public static void log(int sMsg) 5F!i%{XQvm  
{ 4*inN~cU  
System.err.println(sMsg); {R"mvB`  
} {`-AIlH(  
} Hp5.F>-  
-2'+GO7G  
CR;E*I${  
/* ^XG$?2<U  
**TestMethod.java E!uQ>'iq.  
*/ D&i,`j  
package NetFox; U.h2 (-p  
=uEpeL~d;+  
2vhP'?;K  
public class TestMethod { HD3WsIim*  
Z!*6;[]SfG  
~NLthZ(O  
public TestMethod() ouO9%)zv  
{ ///xx/weblogic60b2_win.exe &PMfAo^  
try{ gk;hpO  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); QO>';ul5  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 7]ySj<1  
SiteFileFetch fileFetch = new SiteFileFetch(bean); aX*9T8H/  
fileFetch.start(); @pH6FXVGzt  
} ]z#)XW3#i  
catch(Exception e){e.printStackTrace ();} Fnay{F8z  
)l/ .<`|  
5>UQ3hWo  
} %Y"pVBc  
?uU_N$x  
$zF%F.rln  
public static void main(String[] args) l]j;0i  
{ ]{|lGtK %  
new TestMethod(); Q [C26U  
} $$EEhy  
} 1OqVV?oz  
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