http断点续传简单实现（java)

/* ;%U`lE0  
**SiteFileFetch.java ?rHc%H  
*/ ]`:Fj|>  
package NetFox; O`Z>Oon?  
import java.io.*; $wX5`d1  
import java.net.*; ^s24f?3  
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public class SiteFileFetch extends Thread { F /t;y\)  
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SiteInfoBean siteInfoBean = null; //文件信息Bean uYO?Rb&}  
long[] nStartPos; //开始位置 7 H<_ wW  
long[] nEndPos; //结束位置 cJH7zumM)  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 (cA=~Bw[=  
long nFileLength; //文件长度 S liF$}J  
boolean bFirst = true; //是否第一次取文件 VDQ&BmJE  
boolean bStop = false; //停止标志 LU%g>?m.]  
File tmpFile; //文件下载的临时信息 `D GO~RMp9  
DataOutputStream output; //输出到文件的输出流 hr)TC-  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） r{Fu|aoa;5  
public SiteFileFetch(SiteInfoBean bean) throws IOException 6|9];)  
{ iOD9lR`s  
siteInfoBean = bean; wePMBL1P*  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); w|$;$a7)  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); + ^~n09  
if(tmpFile.exists ()) iAXx`>}m  
{ A 7TP1  
bFirst = false; 3HfT9  
read_nPos(); 2@A7i<p  
} ;N4mR6  
else wV(_=LF  
{ n}._Nb 5  
nStartPos = new long[bean.getNSplitter()]; 9Uk9TG5  
nEndPos = new long[bean.getNSplitter()]; V#sANi?mpo  
} Q2k\8i  
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}  (+Er  
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public void run() _39b8s{  
{ 1M<'^(t3d  
//获得文件长度 cvc.-7IO  
//分割文件 E7j]"\~i  
//实例FileSplitterFetch V:l; 2rW  
//启动FileSplitterFetch线程 "h)+fAT|,  
//等待子线程返回 6:h!gY  
try{ [%bshaY:  
if(bFirst) gE8>5_R|  
{ u/hD9g~H7K  
nFileLength = getFileSize(); AoTL)',  
if(nFileLength == -1) Ho\z^w+T`  
{ v'Lckw@G4  
System.err.println("File Length is not known!"); f5`exfdHE  
} _<5> E  
else if(nFileLength == -2) ^mG-O  
{ 2#|Q=rWB  
System.err.println("File is not access!"); xx41Qw>\W  
} beO*|  
else hQX|wWh  
{ /~AajLxu3W  
for(int i=0;i<nStartPos.length;i++) P:CwC"z>sS  
{ U[Z1@2zLx  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); #<l;YT8  
} @n})oAC,  
for(int i=0;i<nEndPos.length-1;i++) LeO5BmwHR  
{ }.e*=/"MB  
nEndPos = nStartPos[i+1]; ^>]p4Q3 6  
} bD49$N?>  
nEndPos[nEndPos.length-1] = nFileLength; F1MPo;e  
} ,!Ah+x  
} !f"@pR6  
o<%Sr*  
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//启动子线程 )%UO@4  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 9#pl BtQ**  
for(int i=0;i<nStartPos.length;i++) !QC->  
{ N!H
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fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), aIJ[K  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), a*??!  
nStartPos,nEndPos,i); LoNz 1KJL  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); A"w 1GBx  
fileSplitterFetch.start(); %Wu3$b  
} ~2=B:;  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), CQ13fu+|6  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ucB<  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ]k>S0  
nEndPos = " + nFileLength); N)&3(A@  
// fileSplitterFetch[nPos.length-1].start(); _L&C4 <e'  
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XB^z' P{-Y  
//等待子线程结束 -S9$C*t  
//int count = 0; \}G/F
!  
//是否结束while循环 D(L%fK`+  
boolean breakWhile = false; o
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&{l?j>|TM  

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while(!bStop) 3O$Q>.0w/  
{ l$.C40v  
write_nPos(); z`{Ld9W  
Utility.sleep(500); @YV-8;hO  
breakWhile = true; cojuU=i  
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for(int i=0;i<nStartPos.length;i++) =[vT=sHz7  
{ Q- j+#NGc  
if(!fileSplitterFetch.bDownOver) l
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{ u'P@3'P  
breakWhile = false; +FyG{1?<  
break; R%54!f0 %  
} Hz+edMUL  
} H@MUzV  
if(breakWhile) oGXT,38*  
break; e|xRK?aVBu  
r@k&1*&  
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//count++; !=eui$]  
//if(count>4) s_p?3bKu  
// siteStop(); +
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} m<TKy_C`  
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System.err.println("文件下载结束！"); )*$'e<?`  
} u9sffX5x[J  
catch(Exception e){e.printStackTrace ();} xUzfBn  
} -*+7-9A I  
mWCY%o@  
Q
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//获得文件长度 8 w^i  
public long getFileSize() \*a7DuVw  
{ o{nBtxZ"  
int nFileLength = -1; aElEV e3  
try{ iv:[]o  
URL url = new URL(siteInfoBean.getSSiteURL()); B-'Xk{  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 57rc|]C  
httpConnection.setRequestProperty("User-Agent","NetFox"); yj"+!g  
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m[(2  
int responseCode=httpConnection.getResponseCode(); I}$Y[Jve  
if(responseCode>=400) n$B=Vt,  
{ Ws.F=kS>h  
processErrorCode(responseCode); I@7^H48\  
return -2; //-2 represent access is error #.#T+B+9  
} WXaLKiA*(  
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String sHeader; zc\e$MO  
c9r, <TR9  
3Sf<oYF  
for(int i=1;;i++)
)>C,y`,  
{ FdzsWm  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); G-9]z[\#  
//Utility.log(in.readLine()); mGwBbY+5n  
sHeader=httpConnection.getHeaderFieldKey(i); 7WKb| /#;  
if(sHeader!=null) dI{)^  
{ K'Bq@6@C g  
if(sHeader.equals("Content-Length")) @aWvN;v  
{ W=%}~7*  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Mp}aJzmkB;  
break; j^mAJ5  
} YN.rj-;^+  
} L
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else .Hc]?R]  
break; +Ae4LeVzc  
} 349W0>eOT  
} #1&wfI$  
catch(IOException e){e.printStackTrace ();} GUJx?V/[  
catch(Exception e){e.printStackTrace ();} MG<F.u  
/87?U; |V  
yM=%a3  
Utility.log(nFileLength); ,J!G-?:@n  
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return nFileLength; IBo)fE\O  
} ~\
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//保存下载信息（文件指针位置） U#G0  
private void write_nPos() bb}|"m.  
{ n&pi  
try{ ,n-M!y  
output = new DataOutputStream(new FileOutputStream(tmpFile)); :Fm;0R@/k  
output.writeInt(nStartPos.length); N/4`afiV.  
for(int i=0;i<nStartPos.length;i++) .|G([O^H  
{ vB hpD  
// output.writeLong(nPos); QcU&G*   
output.writeLong(fileSplitterFetch.nStartPos); u|BD
=4*  
output.writeLong(fileSplitterFetch.nEndPos); !Z3iu  
} Sbc  
output.close(); /YKg.DA|  
} Q~MV0<{  
catch(IOException e){e.printStackTrace ();} x4r\cL1!  
catch(Exception e){e.printStackTrace ();} d *!)wt  
} j;WZ[g#t  
+Vl\lL -  
:&S6AP  
//读取保存的下载信息（文件指针位置） h
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private void read_nPos() |$f.Qs~?  
{ 9o@5:.b<j  
try{ >ZTRwy`_(  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); XJ^dX]4  
int nCount = input.readInt(); ?>92OuG%W?  
nStartPos = new long[nCount]; ^7G@CBi
c"  
nEndPos = new long[nCount]; f!|7j}3  
for(int i=0;i<nStartPos.length;i++) 8'
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{ ]DHB'NOh,  
nStartPos = input.readLong(); eG55[V<!  
nEndPos = input.readLong(); kc Q~}uFB  
} |_xU{Pu  
input.close(); k?zw4S  
} Oe:+%p  
catch(IOException e){e.printStackTrace ();} |08b=aR6ro  
catch(Exception e){e.printStackTrace ();} 1MkQ$v7m  
} p6VS<L  
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private void processErrorCode(int nErrorCode) ecfw[4B`  
{ G~b/!clN  
System.err.println("Error Code : " + nErrorCode); o EXN$SIs  
} 4! ]28[2B6  
5?9K%x'b  
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//停止文件下载 |=&[sC  
public void siteStop() j>Ce06G  
{ o/I'Qi$v-  
bStop = true; 2uujA* ^  
for(int i=0;i<nStartPos.length;i++) Kx==vq%39  
fileSplitterFetch.splitterStop(); >1q W*  
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} 0&XdCoIe  
} E]Dcb*t  
//负责部分文件的抓取 n]{sBI3  
**FileSplitterFetch.java sl?> X)}  
*/ rWsUWA T*  
package NetFox; v/gxQy+l  
j N":9+F  
&m<:&h& b  
import java.io.*; 90<z*j$EK  
import java.net.*; 2%o@?Rp  
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public class FileSplitterFetch extends Thread { i286 J.  
mu`:@7+Yp  
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String sURL; //File URL T)4pLN E  
long nStartPos; //File Snippet Start Position CNP!v\D  
long nEndPos; //File Snippet End Position [[ {L#  
int nThreadID; //Thread's ID t,H=;U#  
boolean bDownOver = false; //Downing is over O\0]o!  
boolean bStop = false; //Stop identical &q8oalh  
FileAccessI fileAccessI = null; //File Access interface Y]MB/\gj  
drRi<7 i  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException pe%$(%@v  
{ W5a7HkM  
this.sURL = sURL; '$nm~z,V  
this.nStartPos = nStart; 5jMI33D  
this.nEndPos = nEnd; fib#)KE  
nThreadID = id; d!>.$|b  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 8);G'7O  
} l5
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public void run() H 5\k`7R  
{ hJ|zX  
while(nStartPos < nEndPos && !bStop) uUmkk  
{ -]hk2Q0   
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try{
=*2_B~`  
URL url = new URL(sURL); *z852@  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 
^W8kt  
httpConnection.setRequestProperty("User-Agent","NetFox"); zH)M,+P  
String sProperty = "bytes="+nStartPos+"-"; qK=uSLo\+  
httpConnection.setRequestProperty("RANGE",sProperty); nev@ykP6  
Utility.log(sProperty); o,(]w kF  
V7~tIhuJH  
=o_Ua^mr  
InputStream input = httpConnection.getInputStream(); ]]"O)tWHj  
//logResponseHead(httpConnection); ^qR2!fwm<  
;-]' OiS;  
,/%@:Fh4  
byte[] b = new byte[1024]; SHcFnxEAIH  
int nRead; cJ^{iOQ+  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) FUTD/y]Lu  
{ u([|^~H]  
nStartPos += fileAccessI.write(b,0,nRead); [T}Lq~  
//if(nThreadID == 1) *h([ai"1-  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); LZR x>q^  
} fGtYvl O-5  
~9ZW~z'  
"/ 9EUbca  
Utility.log("Thread " + nThreadID + " is over!"); Qvc$D{z  
bDownOver = true; 3fBV SFVS  
//nPos = fileAccessI.write (b,0,nRead); =(aA`:Nl  
} qz_'v{uAj  
catch(Exception e){e.printStackTrace ();} >v?&&FhHK<  
} "O (N=|b  
} \5 S^~(iL  
),!1B%  
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//打印回应的头信息 L|hoA9/]  
public void logResponseHead(HttpURLConnection con) m.6O%jD  
{ i$?$X,  
for(int i=1;;i++) C 9{8!fYp  
{ `xXpP"*o}  
String header=con.getHeaderFieldKey(i); uCB>".'kM  
if(header!=null) 3bU(ea^e$  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Bz+zEXBC  
Utility.log(header+" : "+con.getHeaderField(header)); R"2wop  
else %$Smei
 
break; 5|<jPc  
} ](@HPAG]  
} 7$zeRYD+  
#Ch*a.tI@  
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public void splitterStop() {3LAK[C  
{ [C-4*qOaa2  
bStop = true; .91@T.  
} q}xYme4  
$S6%a9m   
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^>  
} {VmJVO]S  
gJFx#s0?6.  
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/* 7{JIHY+  
**FileAccess.java >}7Ml  
*//文件访问(定位，写) '
qy LQ:6  
package NetFox; o'?[6B>oj  
import java.io.*; h<0&|s*a)  
, RKl  
a #`Y(R'  
public class FileAccessI implements Serializable{ G2y
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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 6k9cvMs%H  
RandomAccessFile oSavedFile; g15~+;33N  
long nPos; YQ-!>3/)-  
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@{q:179w^  
public FileAccessI() throws IOException cF V[k'F  
{ +Y! P VMF  
this("",0); V] 0T P#  
} y>! 8mDvZ  
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public FileAccessI(String sName,long nPos) throws IOException ,j!%,!n o  
{ cp
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oSavedFile = new RandomAccessFile(sName,"rw"); Q8Fqf ;4  
this.nPos = nPos; <zWMTVaC  
oSavedFile.seek(nPos); W/@-i|v  
} Kt5k_9
 
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public synchronized int write(byte[] b,int nStart,int nLen) [,0[\NC  
{ xf4CM,Z7(  
int n = -1; =THRyZCH  
try{ oAprM Z7Y  
oSavedFile.write(b,nStart,nLen); MHqk-4Mz  
n = nLen; g-LMct8$  
} q|zips,  
catch(IOException e) G%F}H/|R  
{ `UD
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e.printStackTrace (); =@ d/SZ|(E  
} or qL0i  
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return n; zL!}YR@&u"  
} S&J>15oWM`  
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} xOt {Vsv  
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@L,4JPk  
/* ty\F~]Oo  
**SiteInfoBean.java .%G>z"Xx  
*/ SpC6dkxD\  
package NetFox; [/Sk+ID  
I} .9  
jB"IJ$cD  
public class SiteInfoBean { JKTn  
w| eVl{~p  

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private String sSiteURL; //Site's URL t2LX@Q"  
private String sFilePath; //Saved File's Path I~F]e|Ehqr  
private String sFileName; //Saved File's Name Ay@/{RZz  
private int nSplitter; //Count of Splited Downloading File 83!{?EPE  
-!QVM\t  
;DgQ8"f  
public SiteInfoBean() "t)$4gERK  
{//nSplitter的缺省值为5 (91 YHhk{  
//default value of nSplitter is 5 "lRxatM  
this("","","",5); e'|IRhr  
} zQ#2BOx1  
6L<QKE=  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) e'A1%g)  
{ HChlkj'7w0  
sSiteURL= sURL; d6e$'w@(\T  
sFilePath = sPath; M2Jb<y]  
sFileName = sName; hem>@Bp'V  
this.nSplitter = nSpiltter; n
{I1ZlEeh  
,L=lg,lH^  
: "^/?Sd  
} B|K^:LUk9  
MxDqp;  
]@!3os,CNF  
public String getSSiteURL() l:+$Ks  
{ v^dQ%+}7>  
return sSiteURL; jG`,k*eUrJ  
} m.68ctaa  
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public void setSSiteURL(String value) O>"T*   
{ ~"VM_Lz]5  
sSiteURL = value; ue1g(;  
} n0QHrIf{  
b!<)x}-t>  
?c
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public String getSFilePath() \h/)un5  
{ fTt\
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return sFilePath; &NX7  
} Qp9QSyMs}  
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public void setSFilePath(String value) eD|"?@cE  
{ !u;gGgQF  
sFilePath = value; 3 MCV?"0  
} ${e5Ka  
hmB`+?,z*  
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public String getSFileName() }wZsM[
NDB  
{ :JU$6  
return sFileName; ;+1ooeU  
} 2^%O%Pc  
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J1w,;T\55  
public void setSFileName(String value) seVT|z  
{ }.1}yz^y  
sFileName = value; +;,X?E]g  
} %\L{Ud%7  
5+2qx)FZ  
:F_>`{  
public int getNSplitter() '~VF
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{ rZ&li/Z
 
return nSplitter; WRrg5&._q  
} z31g"  
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public void setNSplitter(int nCount) ,Jx.Kj.,  
{ Pk;1q?tGw  
nSplitter = nCount; w"O{@2B3:H  
} ^{YK'60  
} {e5-  
Jn%Etz-  
e8M0Lz#}  
/* DVt^O[  
**Utility.java
D`fIw` _  
*/ _>bk'V7  
package NetFox; TK0WfWch  
>)HKruSW.  
'nS>'yYH#  
public class Utility { T 0qM"  
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public Utility()  A"1%E.1  
{ .7M.bpmqE  
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*zMt/d*<&  
} Jpc%i8  
/A+5q\8G  
//线程睡眠 n5#QQk2  
public static void sleep(int nSecond) hj\A-Yf  
{ bYmk5fpRG  
try{ &fsk ESV0  
Thread.sleep(nSecond); T7-yZSw-m  
} Dw>)\\n{Kl  
catch(Exception e) QQ=Kj%R  
{ <\$?.tTZ{  
e.printStackTrace (); &Xc=PQ:I  
} hkRqtpYK  
} OdOn wY  
b`JS&E  
//日志 v4K! BW  
public static void log(String sMsg) WM%w_,Z  
{ #xfav19{.  
System.err.println(sMsg); $KhD>4^jL  
} RY3=UeoF  
+~|Jn_:A f  
G.$KP  
public static void log(int sMsg) Dbb=d8utE  
{ e}n(mq  
System.err.println(sMsg); mmG]|Cl@  
} o+L[o_er  
} m2&Vm~Py6b  
^Nu j/  
KEdqA/F>  
/* J*_^~t  
**TestMethod.java 0+[3>Ny0  
*/ =A
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package NetFox; _~'M
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H?FiZy*[Y  
s8 u`v1  
public class TestMethod { DMTc{  
q#1G4l.  
| O9b  
public TestMethod() s8'!1rHd  
{ ///xx/weblogic60b2_win.exe G$luGxl[  
try{ ]o8yZ x  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); fqBz"l>5A  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); }{kn/m/  
SiteFileFetch fileFetch = new SiteFileFetch(bean); :S}ZF$ $j%  
fileFetch.start(); /0!.u[t)~  
} zqURnsJ  
catch(Exception e){e.printStackTrace ();} ).0p\.W~  
K7C!ZXw~  
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} Vk2%yw>  
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TU;AO%5  
public static void main(String[] args) _yF@k~ h  
{ @=2u;$.  
new TestMethod(); Hzc}NyJ  
} 4E_u.tJ  
} }gFa9M<  
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