http断点续传简单实现（java)

/* \ZH&LPAY  
**SiteFileFetch.java |B^G:7c  
*/ xs!p|  
package NetFox; JhX=l-?  
import java.io.*; yI)~]K r  
import java.net.*; VKW|kU7Cs$  
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public class SiteFileFetch extends Thread { P8I*dvu _  
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SiteInfoBean siteInfoBean = null; //文件信息Bean *#&*`iJ(  
long[] nStartPos; //开始位置 YZE.@Rz  
long[] nEndPos; //结束位置 ~?U*6P)o  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 0X9Y~TM%  
long nFileLength; //文件长度 50~K,Jx6B  
boolean bFirst = true; //是否第一次取文件 ^gYD*K!*  
boolean bStop = false; //停止标志 CxF-Z7 '  
File tmpFile; //文件下载的临时信息 I%lE;'x  
DataOutputStream output; //输出到文件的输出流 $nPAm6mH  
-iN.Iuc{b_  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） jH*)%n5,\  
public SiteFileFetch(SiteInfoBean bean) throws IOException Q8qz*v]{  
{ uk7'K 0j  
siteInfoBean = bean; m*e YC  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ^^Jnv{)  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); EKZVF`L  
if(tmpFile.exists ()) A6"Hk0Hf  
{ }Je>;{&%  
bFirst = false; ;*cLG#&'M  
read_nPos(); \a|L/9%  
} pq!%?m]  
else #"f'7'TE  
{ x\@*60o  
nStartPos = new long[bean.getNSplitter()]; q/gB<p9  
nEndPos = new long[bean.getNSplitter()]; p{Sh F.  
} ?mYYt]R  
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} |$+5@+Zz  
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public void run() %[QV,fD'E  
{ }e]f  
//获得文件长度 39TT{>?`w  
//分割文件 ,,<PVTd  
//实例FileSplitterFetch lU2c_4  
//启动FileSplitterFetch线程 7;}l\VXHm  
//等待子线程返回 o>lmst%<  
try{ yTBS=+X  
if(bFirst) 2eP;[o  
{ TprtE.mP  
nFileLength = getFileSize(); d"Q |I
  
if(nFileLength == -1) $u9]yiY.{  
{ g:#dl\k  
System.err.println("File Length is not known!"); =VP=|g  
} e}{U7xQm1  
else if(nFileLength == -2) V'gw\mcb  
{ qE7R4>5xjO  
System.err.println("File is not access!"); !1sU>Xb4J  
} .ln8|;%  
else Iy7pt~DJ,  
{ k(s;,B\  
for(int i=0;i<nStartPos.length;i++) B]iP't\~  
{ 3OqX/z,  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); XvGA|Ekf<  
} ]!{y a8  
for(int i=0;i<nEndPos.length-1;i++) K k[`dR;  
{ LMl~yqM  
nEndPos = nStartPos[i+1]; /SR^C$h'I  
} SZ!=`a]  
nEndPos[nEndPos.length-1] = nFileLength; I9y.e++/  
} cma*Dc  
} -$a>f4]  
=(, ^du'  
jUMf6^^  
//启动子线程 xF
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; mZvG|P$}  
for(int i=0;i<nStartPos.length;i++) b"j|Bb  
{ #=,(JmQPt  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), #`SD$;  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), KLQ!b,=q  
nStartPos,nEndPos,i); 9IZu$-  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); QLq@u[A  
fileSplitterFetch.start(); 8Jr?ZDf`  
} 8<#U9]  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), )NW6?Pu"  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ]<w:V`(  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 5\4g>5PD  
nEndPos = " + nFileLength); =hH.zrI6e  
// fileSplitterFetch[nPos.length-1].start(); 5z/Er".P  
NucM+r1P  
+|RB0}hFS-  
//等待子线程结束 3{Q,hpZN  
//int count = 0; lhLGG  
//是否结束while循环 7v"lNP-?jU  
boolean breakWhile = false; 3
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":;@Hnb/  
i6PM<X,{;  
while(!bStop) '/%zi,0  
{ UVuDQ  
write_nPos(); )mcEQ-!b  
Utility.sleep(500); I4_d[O9  
breakWhile = true; <,%:   
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for(int i=0;i<nStartPos.length;i++) oR#:NtX
@  
{ K`KLC.j  
if(!fileSplitterFetch.bDownOver) H#d:kilNy  
{ i8pU|VpA  
breakWhile = false; {U11^w1"3  
break; C?Zw6M+  
} Sr.;GS5i  
} kJK,6mN  
if(breakWhile) yfNX7  
break; y&J@?Hc>  
$0Yh!L?\  
34AP(3w  
//count++; ra7uU*  
//if(count>4) ' P"g\;Ij  
// siteStop(); [IBQvL  
} yubSj*  
=!MY4&YX  
r64u31.)  
System.err.println("文件下载结束！"); ! T9
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} Yxd X#3  
catch(Exception e){e.printStackTrace ();} -p,x&h,p  
} b'@we0V@S  
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//获得文件长度  b`mj_b  
public long getFileSize() *JCQu0  
{ *wbZ;rfF  
int nFileLength = -1; 8cg`7(a  
try{ D^F{uDlb  
URL url = new URL(siteInfoBean.getSSiteURL()); 3TuC+'`G  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); \k8rxW  
httpConnection.setRequestProperty("User-Agent","NetFox"); keAcKhj  
}E^S]hdvz  
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int responseCode=httpConnection.getResponseCode(); B0UJq./`  
if(responseCode>=400) ZXb0Y2AVx  
{ hq>Csj==@  
processErrorCode(responseCode); g=)J~1&p  
return -2; //-2 represent access is error <g2_6C\j  
} %g"eV4j  
"dh:-x6  
)hKS0`$|  
String sHeader; }OShT+xeX  
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>um
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for(int i=1;;i++) `(4pu6uT  
{ XR+3j/zEQ  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); +FFG#6e  
//Utility.log(in.readLine()); 4jmK].  
sHeader=httpConnection.getHeaderFieldKey(i); S5=Udd"  
if(sHeader!=null) 4N?v  
{ I?!rOU=0  
if(sHeader.equals("Content-Length")) -0HkTY  
{ 5ua?I9fY  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ,5k-.Md>2*  
break; I0= NaZ7  
} "i)Yvh[y  
} do/)~9[4\  
else mXWTm%'[  
break; I=DLPgzO9  
} |PVt}*0"  
} M@UVpQwgv  
catch(IOException e){e.printStackTrace ();} l0]
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catch(Exception e){e.printStackTrace ();} ;.
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Utility.log(nFileLength); LX+5|u  
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return nFileLength; yWIm&Q:  
} Xo5$X7m  
|?m` xO  
tV;%J4E'  
//保存下载信息（文件指针位置） HaNboYW_K  
private void write_nPos() /)|X.D  
{ v@ C,RP9  
try{ 7()?C}Ni-  
output = new DataOutputStream(new FileOutputStream(tmpFile)); gz#4{iT~  
output.writeInt(nStartPos.length); L-i>R:N4  
for(int i=0;i<nStartPos.length;i++) ]5CNk+`'  
{ @ CsV]97`  
// output.writeLong(nPos); ,lN5,zI=S  
output.writeLong(fileSplitterFetch.nStartPos); / l>.mK()  
output.writeLong(fileSplitterFetch.nEndPos); =Ov7C[(  
} Do-^S:.  
output.close(); H3/c
aN:  
} {kB `>VS  
catch(IOException e){e.printStackTrace ();} >O`l8tM  
catch(Exception e){e.printStackTrace ();} eBW=^B"y+  
} %B2XznZ:  
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X~T/qFS  
//读取保存的下载信息（文件指针位置） C"<s/
h  
private void read_nPos() TvhJVVQ+?  
{ N0TeqOi4Y  
try{ Ibr%d2yS=  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 8Cf|*C+_'  
int nCount = input.readInt(); 6Y*;{\Rd  
nStartPos = new long[nCount]; 70W"G X&  
nEndPos = new long[nCount]; ]TpU"JD  
for(int i=0;i<nStartPos.length;i++) U\<-mXv  
{ T3J'fjY  
nStartPos = input.readLong(); C9tb\?#  
nEndPos = input.readLong(); @|-OJ4[5  
} Qc-(*}  
input.close(); ;6;H*Y0,|E  
} P~$<X  
catch(IOException e){e.printStackTrace ();} 'A{h iY  
catch(Exception e){e.printStackTrace ();} R'K/t|MC  
} >=,uau7  
F#r#}.B='U  
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private void processErrorCode(int nErrorCode) `x8Bn"  
{ 7_jE[10  
System.err.println("Error Code : " + nErrorCode); !AHAS  
} ;<Qdy` T  
_]>JB0IY  
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//停止文件下载 S\C*iGeqJ  
public void siteStop() _kraMQ>  
{ !>.vh]8g  
bStop = true; nS.G~c|  
for(int i=0;i<nStartPos.length;i++) /MTf0^9  
fileSplitterFetch.splitterStop(); Fe=8O ^\  
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} &_-](w`  
} Mhpdaos  
//负责部分文件的抓取  $g8}^1  
**FileSplitterFetch.java ^QL 877  
*/ -AD2I {C  
package NetFox; |Fln8wB  
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NlPS#  
import java.io.*; 2Oc$+St~8  
import java.net.*; {ISE'GJj  
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public class FileSplitterFetch extends Thread { (|h:h(C  
jZ9[=?   
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String sURL; //File URL ]KK`5Dv|,e  
long nStartPos; //File Snippet Start Position I.
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long nEndPos; //File Snippet End Position U@lV  
int nThreadID; //Thread's ID yyl#{Nl@t  
boolean bDownOver = false; //Downing is over Q
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boolean bStop = false; //Stop identical Cnh|D^{s  
FileAccessI fileAccessI = null; //File Access interface ,Qc.;4s-  
7XAvd-  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException F9o6V|v  
{ |m>}
%{  
this.sURL = sURL; ~1 ZD[@  
this.nStartPos = nStart; b5`KB75sbo  
this.nEndPos = nEnd; c.K =(y*  
nThreadID = id; nYw\'c  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 f=:.BR{  
} 5~VosUpe7  
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public void run() 2W$lQ;iO  
{ SG]
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while(nStartPos < nEndPos && !bStop) WStnzVe  
{ T 1Cs>#)  
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"Ai6<:ml  
try{ 1"E\C/c  
URL url = new URL(sURL); F+aQ $pQ  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); :F(9"L  
httpConnection.setRequestProperty("User-Agent","NetFox"); LJuW${Y  
String sProperty = "bytes="+nStartPos+"-"; 8C&x MA^  
httpConnection.setRequestProperty("RANGE",sProperty); 9C}qVoNu  
Utility.log(sProperty); {U @3yB  
&"S/Lt  
+<(a}6dt  
InputStream input = httpConnection.getInputStream(); &^QPkX@p  
//logResponseHead(httpConnection); AlX3Wv}  
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A" !n1P
 
byte[] b = new byte[1024]; x mo&![P  
int nRead; ZwJciT!_~  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) sBW3{uK  
{ 9YKDguG  
nStartPos += fileAccessI.write(b,0,nRead); kK[duW=6  
//if(nThreadID == 1) S!dHNA:iU  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); c~Kc7}I  
} 7`Du5>b8  
_/x&<,3  
9M2f!kJP$  
Utility.log("Thread " + nThreadID + " is over!"); v*TeTA %  
bDownOver = true; WmVVR>0V|  
//nPos = fileAccessI.write (b,0,nRead); K8Zt:yP  
} 3N%{B  
catch(Exception e){e.printStackTrace ();} (_8#YyW#  
} FmT `Oa>  
} Mtp%co)f  
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6Z
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//打印回应的头信息 lo:~aJ8  
public void logResponseHead(HttpURLConnection con) Q"}s>]k3_  
{ L3c*LL  
for(int i=1;;i++) d6b.z
P  
{ Y3oMh,  
String header=con.getHeaderFieldKey(i); i?>Hr|  
if(header!=null) lX;mhJj!  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); rg)h
5G  
Utility.log(header+" : "+con.getHeaderField(header)); #+G`!<7/@f  
else }~zO+Wf2  
break; Uf2:gLrF  
} c E76L%O  
} xqWj|jA  
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K`(#K#n  
public void splitterStop() ^KH%mSX>  
{ 42@a(#z(U  
bStop = true; fValSQc!U  
} $ I<|-]u  
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} >d%VDjk .  
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/* ]
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**FileAccess.java DTy/jaK  
*//文件访问(定位，写) M&e8zS  
package NetFox; EAyukM2  
import java.io.*; #s^s_8#&e  
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<%?uYCD  
public class FileAccessI implements Serializable{ lU$X4JBzS  
^x3EotQ\  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 z93nYY$`Y  
RandomAccessFile oSavedFile; ;&mxqY8`'  
long nPos; 6ZgNHARS  
p#<nK+6.8  
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public FileAccessI() throws IOException VM;g+RRq  
{ e6m1NH4,  
this("",0); ZR mPP  
} ?!m ma\W  
/Sj_y*x1e  
;Jo*|pju  
public FileAccessI(String sName,long nPos) throws IOException qw0~*0}  
{ fLM.kCD?u  
oSavedFile = new RandomAccessFile(sName,"rw"); +$~8)95<B  
this.nPos = nPos; Oga1u  
oSavedFile.seek(nPos); ,\>g  
} ua:9`+Dff  
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public synchronized int write(byte[] b,int nStart,int nLen) d+1x*`U|  
{ [x$;XqA  
int n = -1; f?m5pax|  
try{ %*p^$5L<  
oSavedFile.write(b,nStart,nLen); U,HS;wo;t  
n = nLen; 6vWii)O.D  
} JD-Becz  
catch(IOException e) $QffrU'  
{ '\'7yN'  
e.printStackTrace (); >3$uu+p1F  
} !Sfe{/$w  
&<t79d%{  
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return n; ](n69XX_  
} !ABLd|tP  
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} ec1Fg0Fa  
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o
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/* e sGlMq  
**SiteInfoBean.java |
is 9  
*/ Crg#6k1~EN  
package NetFox; ~=F
k/  
QU%N*bFW%P  
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public class SiteInfoBean { #'KY`&Tw&  
Tz2x9b\82  
> XZg@?Iw  
private String sSiteURL; //Site's URL ^@Y9!G=  
private String sFilePath; //Saved File's Path &gJW6<  
private String sFileName; //Saved File's Name 6ku8`WyoF  
private int nSplitter; //Count of Splited Downloading File d}pGeU'  
d4V 2[TX  
\CDAFu#  
public SiteInfoBean() P 4H*jy@?  
{//nSplitter的缺省值为5 `43vxcMg  
//default value of nSplitter is 5 uzO{{S-  
this("","","",5); % dYI5U89  
} bsMC#xT  
|&(H^<+Xp  
o KlF5I  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Qw}xGlF,  
{ ko>M&/^  
sSiteURL= sURL; pj j}K  
sFilePath = sPath; XWc|[>iO  
sFileName = sName; 69-$Wn43<  
this.nSplitter = nSpiltter; y^, "gD  
'&/(oJ;O~  
4fD`M(wv  
} Px$'(eMj^3  
ud.poh~|  
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public String getSSiteURL() .^BWR  
{ 01-p `H+  
return sSiteURL; ?3n=m%W,J*  
} e5FCqNip'  
s^obJl3
 
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public void setSSiteURL(String value) 7Y4%R`9H  
{ p-a]"l+L  
sSiteURL = value; _pJX1_vD  
} fO0-N>W'P  
*P&OxVz  
?Z5$0-g'hU  
public String getSFilePath() uAChu]  
{ MG;4M>H  
return sFilePath; IM$'J  
} LxIuxt=X|p  
`Nkx7Z~w:  
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public void setSFilePath(String value) o:h)~[n|  
{ byp.V_a}/  
sFilePath = value; W5T
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} #cR57=M}  
twAw01".  
p0"BO4({{  
public String getSFileName() U9bFUK/z  
{ TeOFAIU  
return sFileName; FW/6{tm  
} 1a \=0=[  
M_yZR^;^-  
oC5gME"2  
public void setSFileName(String value) N45s'rF  
{ OX'/?B((  
sFileName = value; qdKh6{  
} }o~Tw?z-|  
)kFme=;  
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public int getNSplitter() 5L/Yi  
{ :/ ~):tM  
return nSplitter; v\J!yz  
} =#7s+d-  
C,V|TF.i2  
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public void setNSplitter(int nCount) Kv(Y }  
{ 3xc:Y> *`  
nSplitter = nCount; 0^-z?Kb<}  
} mm3zQ!2j.  
} A)=X?x  
@oUf}rMiDa  
Z`e$~n(Bh  
/* AEBw#v!,o  
**Utility.java KB$ vQ@N  
*/ =iA"; x  
package NetFox; r9U[-CX:"  
<6~/sa4GN  
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l  
public class Utility { !.x=r  
G:H(IA7Z  
<e@I1iL37y  
public Utility() Ly@U\%.  
{ ,Gf+U7'K  
I$rW[l2  
"i;*\+x  
} j(wY/Hl  
"Wzij&WkQ  
//线程睡眠 Z3&XTsq  
public static void sleep(int nSecond) T#ecLD#  
{ vLVSZX
 
try{ Ktj(&/~}  
Thread.sleep(nSecond); T1Ln)CS?9  
} 1K
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catch(Exception e) #$9U=^Z[  
{ 2nOe^X!*  
e.printStackTrace (); 9&?tQ"@x  
} q{N lF$X  
} B{=,VwaP_  
6'3Ey'drH  
//日志 6EW"8RG`  
public static void log(String sMsg) >B|ofwm*  
{ ulJ+:zwq$  
System.err.println(sMsg); / r`Y'rm  
} 6"#Tvj~-8  
y0W`E/1t  
?Vb=4B{~  
public static void log(int sMsg) -M(58/y  
{ @DjG?yLK$  
System.err.println(sMsg); YQlpk@X`2  
} )[a?J,  
} zXA= se0U  
[bQ8A(u  
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/* [xH2n\7  
**TestMethod.java IWSEssP  
*/ av$\@4I  
package NetFox; 2g`uC}  
@=^jpSnZ  
vCrWA-q#  
public class TestMethod { .-gm"lB  
LQuYCfj|  
o>!~*b';g,  
public TestMethod() 9 ;! uV>-H  
{ ///xx/weblogic60b2_win.exe pD)/-Dgdm  
try{ W"DxIy  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); JN9HT0  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); `s]zk {x  
SiteFileFetch fileFetch = new SiteFileFetch(bean); G+%5V5GS  
fileFetch.start(); FZLzu  
} xfZ9&g  
catch(Exception e){e.printStackTrace ();} J^e|"0d  
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t2U]CI%  
} *PA1iNdKS  
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public static void main(String[] args) ~S~x@&yR  
{ _@}MGWlAPt  
new TestMethod(); <CdG[Ih  
} RaJ}>e  
} FkkZyCqZ`  
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