http断点续传简单实现（java)

/* P(gID  
**SiteFileFetch.java 5In8VE !P  
*/ h,RUL  
package NetFox; !B38! L  
import java.io.*; "oGM>@q=B  
import java.net.*; r:\5/0(  
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public class SiteFileFetch extends Thread { m"> =QP  
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SiteInfoBean siteInfoBean = null; //文件信息Bean Ydd>A\v\;  
long[] nStartPos; //开始位置 i)^ZH#Gp  
long[] nEndPos; //结束位置 | 3/p8  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Bv|9{:1%X}  
long nFileLength; //文件长度 !-}*jm p<  
boolean bFirst = true; //是否第一次取文件 UK9MWC5g9  
boolean bStop = false; //停止标志 o[+|n[aT)3  
File tmpFile; //文件下载的临时信息 9;WOqBD  
DataOutputStream output; //输出到文件的输出流 :FgRe,D  
x@RA1&c  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） CjukD%>sde  
public SiteFileFetch(SiteInfoBean bean) throws IOException ;w&yGm  
{ 7)8}8tY^{  
siteInfoBean = bean; k=/|?%  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 2dlV'U_g  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); .KMi)1L)  
if(tmpFile.exists ()) E3C[o! 5  
{  `:  
bFirst = false; \EfwS% P  
read_nPos(); blkJm9]v  
} &@Gu~)^(  
else m.g@S30  
{ ~;4k UJD  
nStartPos = new long[bean.getNSplitter()]; +W3>Yg%)X  
nEndPos = new long[bean.getNSplitter()]; B*?PB]  
} >+LgJo R  
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} "ddH7:(k<  
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public void run() 'ah0IYe  
{ '/*rCB  
//获得文件长度 ?cxK~Y\  
//分割文件 }4ju2K  
//实例FileSplitterFetch a9_KQ=&CI  
//启动FileSplitterFetch线程 JBJ7k19;  
//等待子线程返回 40sLZa)e  
try{ P+|8MT0  
if(bFirst) %H~gN9Vn#@  
{ #\;w
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nFileLength = getFileSize(); s7.*o@G  
if(nFileLength == -1) ; SM^  
{ :NyEd<'  
System.err.println("File Length is not known!"); YD.^\E4o  
} :|mkI#P.  
else if(nFileLength == -2) ~F6gF7]z  
{ 4gNRln-
 
System.err.println("File is not access!"); ~,65/O  
} 6OW-Dif^AG  
else JX<W[P>M  
{ n^)9QQ  
for(int i=0;i<nStartPos.length;i++) %4KJ&R (>[  
{ *w,gi.Y3  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); T1di$8  
} EKw\a  
for(int i=0;i<nEndPos.length-1;i++) !27]1%Aw  
{ U:jf9L2  
nEndPos = nStartPos[i+1]; (`Mz.VN  
} ?YykCJJ ~@  
nEndPos[nEndPos.length-1] = nFileLength; +E[
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} w[G_w:$a  
} ~,1q :Kue  
6EWB3.x19  
{EN@,3bA  
//启动子线程 BT#g?=n#`  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; }f'1x%RS^  
for(int i=0;i<nStartPos.length;i++) @O @yJ{(I  
{ ,#O8:s  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ?C2;:ol  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), j7+t@DqQ  
nStartPos,nEndPos,i); vp9<.*h  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); _7.y4zQJ  
fileSplitterFetch.start(); jch8d(`?d  
} ay|{!MkQ  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Y6PA\7Y\  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); xJGeIh5  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", s@iCfXU  
nEndPos = " + nFileLength); nv{4 U}&P  
// fileSplitterFetch[nPos.length-1].start(); x7@HPf  
?zu{&aOX|  
qE:DJy<  
//等待子线程结束 *
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//int count = 0; W-QPO  
//是否结束while循环 X5<.%@Z  
boolean breakWhile = false; xB+H7Ya  
[wG%@0\  
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while(!bStop) ]w_)Spo.  
{ c/U6K yiK  
write_nPos(); @v=q,A8_  
Utility.sleep(500); fMaNv6(  
breakWhile = true; VrxH6Y  
BAHx7x#(  
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for(int i=0;i<nStartPos.length;i++) kR(=VM JU  
{ 2f4c;YS  
if(!fileSplitterFetch.bDownOver) lHqx}n@e  
{ jy2nn:1#^  
breakWhile = false; 1iDo$]TEK  
break; Af<>O$$6  
} "6QMa,)D  
} d]`,}vi#E9  
if(breakWhile) *)I1gR~  
break; @E;pT3; )  
b15qy?`y  
j #YFwX4.  
//count++; f|0QN#$  
//if(count>4) 4
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// siteStop(); =fo/+m5  
} gAP}KR#T  
,+9r/}K]/  
 gVkI=J  
System.err.println("文件下载结束！"); uJ[Vv4N%9  
} xrnH=>.;m  
catch(Exception e){e.printStackTrace ();} $SR]7GZ  
} AgJ~6tK  
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>6+K"J-@  
//获得文件长度 3wl>a#
f  
public long getFileSize() X+8p2xSO|  
{ /)T
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int nFileLength = -1; }}1Q<puM  
try{ V}-o):dI|  
URL url = new URL(siteInfoBean.getSSiteURL()); V p{5K
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Y_sVe  
httpConnection.setRequestProperty("User-Agent","NetFox"); ]'/]j  
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int responseCode=httpConnection.getResponseCode(); ;$< ek(i7  
if(responseCode>=400) 4N j?UDa  
{ )7J>:9h  
processErrorCode(responseCode); 5zOSb$;  
return -2; //-2 represent access is error B,,d~\  
} >,Z{wxzJ  
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String sHeader; Bnq\Gg  
yw!`1#3.  
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for(int i=1;;i++) w-Fk&dC69  
{ xS1|Z|&
 
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); e]?S-J'z  
//Utility.log(in.readLine()); F2'cL@E3  
sHeader=httpConnection.getHeaderFieldKey(i); [hbp#I~*[  
if(sHeader!=null) #57z-x[1  
{ 0+LloB  
if(sHeader.equals("Content-Length")) t@M] ec  
{ IIiN1 Lu,5  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); iZk``5tPE  
break; G9Tix\SpF  
} pr(\?\a  
} taaAwTtk?A  
else DU8LU*q'  
break; S '+"+%^tj  
} k1zt|  
} U{(07GNm#  
catch(IOException e){e.printStackTrace ();} aS G2K0  
catch(Exception e){e.printStackTrace ();} ts>}>}@vc  
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Utility.log(nFileLength); ]i2\2MTW8  
(=V[tI+Ngt  
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return nFileLength; c@M@t0WT[  
} b0 `9wn  
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//保存下载信息（文件指针位置） Pc==]H(  
private void write_nPos() :j4 [_9\  
{ uF"`y&go  
try{ *!@x<Hf<  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 7g+]  
output.writeInt(nStartPos.length); #SNI dc>9\  
for(int i=0;i<nStartPos.length;i++) Fg_s'G,`  
{ ,5*xE\9G  
// output.writeLong(nPos); uiA:(2AQ  
output.writeLong(fileSplitterFetch.nStartPos); 5T#D5Z<m  
output.writeLong(fileSplitterFetch.nEndPos); RQNi&zX/  
} 4LJ}>e  
output.close(); X{9o8 *V  
} j],.`Y  
catch(IOException e){e.printStackTrace ();} tta0sJ8i  
catch(Exception e){e.printStackTrace ();} tdF[2@?+  
} F:GKnbY  
;@~*z4U  
:Xh`.*{EX  
//读取保存的下载信息（文件指针位置） QC,(rB  
private void read_nPos() KdsvZim0>  
{ :9#{p^:o  
try{ l?_!eA  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); \RyA}P5S  
int nCount = input.readInt(); -wMW@:M_  
nStartPos = new long[nCount]; b)^ZiRW``  
nEndPos = new long[nCount]; -GVG1#5  
for(int i=0;i<nStartPos.length;i++) HWOs@!cL  
{ [qMdOY%jx  
nStartPos = input.readLong(); ?4Juw?  
nEndPos = input.readLong(); 2_b'mepV  
} %v:h]TA  
input.close(); K/m)f#  
} u@u.N2H
.%  
catch(IOException e){e.printStackTrace ();} FD+PD:cQn  
catch(Exception e){e.printStackTrace ();} TFDCo_>o  
} }h h^U^ia  
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private void processErrorCode(int nErrorCode) w*}yw"gP*0  
{ [iy;}5XK  
System.err.println("Error Code : " + nErrorCode); ~c$ts&Cl  
} C?|3\@7  
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//停止文件下载 |ZlT>u  
public void siteStop() 166c\QO  
{ ]pTw]SK  
bStop = true; .ASwX  
for(int i=0;i<nStartPos.length;i++) '?3z6%
 
fileSplitterFetch.splitterStop(); pt
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} 'oQP:*Btl3  
} s Xk?.A_D  
//负责部分文件的抓取 )pn7DIXG  
**FileSplitterFetch.java rtmt3  
*/ 15o *r  
package NetFox; ,Ysl$^\  
,T*_mDVY  
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import java.io.*; %7d@+ .  
import java.net.*; m&0BbyE.z  
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public class FileSplitterFetch extends Thread { ,xD*^>!  
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String sURL; //File URL iZ6C8HK&&  
long nStartPos; //File Snippet Start Position s_Oh >y?Aq  
long nEndPos; //File Snippet End Position ;Pqyu ?  
int nThreadID; //Thread's ID q&d&#3Rh  
boolean bDownOver = false; //Downing is over 3H}~eEg,  
boolean bStop = false; //Stop identical }>X\"  
FileAccessI fileAccessI = null; //File Access interface SA+%c)j29  
L[Yp\[#-q  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException s?x>Yl %  
{ 'BdmFKy1  
this.sURL = sURL; oT (:33$  
this.nStartPos = nStart; 0mD;.1:  
this.nEndPos = nEnd; Y!1^@;)^  
nThreadID = id; cm 9oG  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 VIYksv   
} P[GX}~_k  
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public void run() 2]aZe4H.  
{ x+y!P  
while(nStartPos < nEndPos && !bStop) j YIV^o 0  
{ }8F$& AFt  
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try{ !Xx<~lIC  
URL url = new URL(sURL); hp]ng!I{\u  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); +fP/|A8P  
httpConnection.setRequestProperty("User-Agent","NetFox"); l^UJ
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String sProperty = "bytes="+nStartPos+"-"; 7?!Z+r  
httpConnection.setRequestProperty("RANGE",sProperty); -Xxu/U})%  
Utility.log(sProperty); <\d|=>;  
$,e?X}4  
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InputStream input = httpConnection.getInputStream(); f{^M.G@  
//logResponseHead(httpConnection); k#Ez  
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byte[] b = new byte[1024]; x !:9c<  
int nRead; !` M;#  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 3q|cZQK!1  
{ >4|c7z4  
nStartPos += fileAccessI.write(b,0,nRead); lKV\1(`  
//if(nThreadID == 1) kBiBXRt  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); l'7Mw%6{  
} *L;pcg8{  
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Utility.log("Thread " + nThreadID + " is over!"); -q&7J' N  
bDownOver = true; "0H56#eW  
//nPos = fileAccessI.write (b,0,nRead); oWx_O-_._  
} ;]&~D +XH  
catch(Exception e){e.printStackTrace ();} bQdSX8: !R  
} 5Q$r@&qp  
} eN]>l  
)zW%\s*
'  
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//打印回应的头信息 4P4 Fo1  
public void logResponseHead(HttpURLConnection con) Zc%foK
{  
{ P!FEh'.  
for(int i=1;;i++) kByrhK5U  
{ Q$3\ /mz  
String header=con.getHeaderFieldKey(i); oEQ{m5O9  
if(header!=null) i[2bmd!H
 
//responseHeaders.put(header,httpConnection.getHeaderField(header)); s^g.42?u  
Utility.log(header+" : "+con.getHeaderField(header)); .L^pMU+!^  
else p2Dh3)&  
break; <g3du~  
} rQcRjh+E H  
} UR1JbyT  
5e#&"sJ.1  
8R\>FNk;  
public void splitterStop() \]T=j#.S$  
{ fou_/Nrue  
bStop = true; 2&.n  
} =sE2}/g  
#*Yi4Cn<  
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}
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/* 7b&JX'`Mb  
**FileAccess.java X-)RU?  
*//文件访问(定位，写) fO^e+Mz  
package NetFox; cBLR#Yu;O5  
import java.io.*; 4{;8:ax&w  
([,vX"4  
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public class FileAccessI implements Serializable{ =My}{n[  
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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 0%xR<<gir  
RandomAccessFile oSavedFile; 3XeXzPj  
long nPos; 9;0V  /y  
)-+\M_JK5  
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public FileAccessI() throws IOException <%d51~@={I  
{ gDQkn {T.%  
this("",0); nT.L}1@  
} aO.\Qe+j  
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h4CTTe)  
public FileAccessI(String sName,long nPos) throws IOException =tr1*s{  
{ RzA2*]%a  
oSavedFile = new RandomAccessFile(sName,"rw"); E`Jp(gK9F  
this.nPos = nPos; &W=V%t>Z  
oSavedFile.seek(nPos); <w0NPrS]  
} -{X<*P4p  

ixIV=#  
|SGgy|/a#  
public synchronized int write(byte[] b,int nStart,int nLen) (Wd_G-da  
{ << 3 a<I  
int n = -1; :+~KPn>w5  
try{ _PXG AS  
oSavedFile.write(b,nStart,nLen); q>_vE{UB  
n = nLen; =n@F$/h  
} $; Q$W9+  
catch(IOException e) vkd[:CC  
{ KX?o nsZ  
e.printStackTrace (); %55@3)V8Rf  
} <eB<^ &nd  
I jZ]_*^!  
$_Y/'IN`k  
return n; J=I:T2bV&s  
} WnD^F>  
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} XB0a dp  
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h ?uqLsRl  
/* ;% 2wGT  
**SiteInfoBean.java )!tCC-Cr  
*/ B\Xh3l]+j  
package NetFox; kTnOmAw  
>qR7'QwP  
vB[~pQ;Z  
public class SiteInfoBean { <,\ `Psa)N  
W7H&R,  
P @zz"~f7  
private String sSiteURL; //Site's URL  }10\K  
private String sFilePath; //Saved File's Path ,Pn-ZF  
private String sFileName; //Saved File's Name (2U
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private int nSplitter; //Count of Splited Downloading File z0#-)AeS  
HbcOTd)=5  
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public SiteInfoBean() o4$Ott%Wm  
{//nSplitter的缺省值为5 gfi AK%  
//default value of nSplitter is 5 KX!i\NHz  
this("","","",5); 6gXIt9B.h$  
} <lUOJV{&\  
_`H.h6h  
K
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) <"W?<VjO  
{ ))!Bg?t-  
sSiteURL= sURL; #Mh{<gk%ax  
sFilePath = sPath; X*i/A<Y`=  
sFileName = sName; wMGk!N  
this.nSplitter = nSpiltter; {jjSJIV1  
>*IN  
rah,dVE]  
} 7W"/N#G  
x<)G( Xe*  
 >1A*MP4  
public String getSSiteURL() OA[&Za#w  
{ 9Gca6e3  
return sSiteURL; - ay5  
} O`WIkBV!  
>
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public void setSSiteURL(String value) Z,K7Ot0  
{ (:5G#?6,  
sSiteURL = value; 9qK
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} Y$g}XN*)E  
`-_N@E1'>  
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public String getSFilePath() 98fu>>*G{  
{ ;imRh'-V6  
return sFilePath; f/,tgA  
} h35Hu_c&  
'0:i<`qv#g  
77V .["=7  
public void setSFilePath(String value) 9}5K6aQ  
{ bLqy!QE  
sFilePath = value;  B$^7h!  
} R[LsE^  
i(*I@ku  
*5e+@rD`  
public String getSFileName() Bd@'e7{  
{ Zk&h:c  
return sFileName; w5*Z!  
} Jic}+X*0  
{^5?)/<  
9XX>A*  
public void setSFileName(String value) !Vheq3"q/  
{ RW_q~bA9  
sFileName = value; 1S0pd-i  
} 4,G w#@  
|ETiLR=&  
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public int getNSplitter() 'xnnLCm.
 
{ X<]qU3k5  
return nSplitter; XX6 T$pA6  
} n,j$D62[  
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public void setNSplitter(int nCount) Ri#H.T<'  
{ B@O@1?c[  
nSplitter = nCount; at6149B\)  
} #`;/KNp 9  
} WZZ4]
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-Xz&}QA  
/* 5l DFp9  
**Utility.java ]X
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*/ C5W>W4EM  
package NetFox; S[,8TErz  
Vw#{C>  
:!fG; )
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public class Utility { *1{S*`|cJy  
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public Utility() K-eY|n  
{ ifK%6o6  
~]'pY  
U7iuY~L  
} jN0k9O>  
%O%=rUD  
//线程睡眠 pFsc}R/0/8  
public static void sleep(int nSecond) 93O;+Z5J  
{ O7t(,uox3y  
try{ Vp}
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Thread.sleep(nSecond); in-C/m#  
} Q;u SWt<{  
catch(Exception e) ]3Dl)[R   
{ ,xI%A, (,;  
e.printStackTrace (); 'b/<x|  
} 7@}$|u:JUF  
} 28andfl  
gNpJ24QK  
//日志 ;WU<CKYG*  
public static void log(String sMsg) >dzsQ^Nj  
{ AeuX Qt  
System.err.println(sMsg); (08I  
} ,#]t$mzbQ(  
j'0r'  
?7MqeR4/E  
public static void log(int sMsg) =Gk/k}1  
{ &~e$:8+  
System.err.println(sMsg); :_kAl? eJ  
} J;$N{"M  
} wsU V;S*X%  
" =] -%B  
QK`i%TXJ  
/* Cx_Q:6T  
**TestMethod.java !0,Mp@ j/  
*/ ,TJD$^  
package NetFox; EGq;7l6u&?  
nqVZqX@oE  
kcie}Be  
public class TestMethod { 8>WVodv  
V DS23Bo  
)yK[Zb[  
public TestMethod() HO)/dZNU  
{ ///xx/weblogic60b2_win.exe 4Kwh?8.  
try{ WQNE2Q  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); f:B>zp;N  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 9Z5D\yv?H  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 5kNzv~4B,;  
fileFetch.start(); SLfFqc+n0  
} 'CZa3ux  
catch(Exception e){e.printStackTrace ();} X|D!VX>#!  
YW\0k5[  
R%D'`*+  
} U$dh1;  
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public static void main(String[] args) WKz> !E%  
{ 9`//^8G:=  
new TestMethod(); -u!FOD/  
} `1OgYs  
} 2lKV#9"  
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