http断点续传简单实现（java)

/* 1(7.V-(G  
**SiteFileFetch.java wW! r}I#  
*/ tDHHQ  
package NetFox; Yj7= T%5  
import java.io.*; JBEgiQ/  
import java.net.*; >dvWa-rNUT  
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public class SiteFileFetch extends Thread { v&b.Q:h*'  
>{qK]xj  
i,Wm{+H-O  
SiteInfoBean siteInfoBean = null; //文件信息Bean rjAkpAT  
long[] nStartPos; //开始位置 Zjic"E1  
long[] nEndPos; //结束位置 nB@iQxcz  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 j YIV^o 0  
long nFileLength; //文件长度 Ma=6kX]  
boolean bFirst = true; //是否第一次取文件 >yA,@%X  
boolean bStop = false; //停止标志 ~d7Wjn$@  
File tmpFile; //文件下载的临时信息 J6( RlHS;  
DataOutputStream output; //输出到文件的输出流 y.*=Ww+  
8Z4?X%  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） Q^MXiEO+  
public SiteFileFetch(SiteInfoBean bean) throws IOException $,e?X}4  
{ =Kt9,d08x  
siteInfoBean = bean; /q"d`!h)w  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 4$zFR}f  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Jm(&G  
if(tmpFile.exists ()) /#qs(! d  
{ bxhg*A  
bFirst = false; lKV\1(`  
read_nPos(); i+X2M-[Ls  
} 5h|m4)$  
else ( ztim  
{ yXTK(<'  
nStartPos = new long[bean.getNSplitter()]; #mRFUA  
nEndPos = new long[bean.getNSplitter()]; I)XOAf$6  
} WE.$at{*h  
m/<F 5R  
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} q M_/  
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5qd_>UHp  
public void run() o4/I1Mq  
{ #6N+5Yx_[  
//获得文件长度 1qLl^
DW  
//分割文件 s^g.42?u  
//实例FileSplitterFetch &}nBenYp  
//启动FileSplitterFetch线程 pM&]&
Nk  
//等待子线程返回 -3G 4vRIo  
try{ +^4BO`   
if(bFirst) a/QtJwIV  
{
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nFileLength = getFileSize(); SE;Tujwhqi  
if(nFileLength == -1) C(V[wvL  
{ b46[fa  
System.err.println("File Length is not known!"); BKC7kDK3H  
} g|K6iY  
else if(nFileLength == -2) =f4[=C$&`  
{  (# 6<k  
System.err.println("File is not access!"); |*tWF! D6`  
} RIy5ww}3|  
else MX!u$ei  
{ &Y54QE".  
for(int i=0;i<nStartPos.length;i++) _{LN{iqDv  
{ *L%6qxl`V  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 7Wwp )D  
} #`jE%ONC  
for(int i=0;i<nEndPos.length-1;i++) N5 SLF4R1  
{ -?< Ww{  
nEndPos = nStartPos[i+1]; aho'|%y)  
} Q_&}^  
nEndPos[nEndPos.length-1] = nFileLength; RzA2*]%a  
} 4M @oj  
} `Yx-~y5X  
2;r]gT~  
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//启动子线程 lx\qp`w  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ?EI'^xg  
for(int i=0;i<nStartPos.length;i++) _PXG AS  
{ hLb;5u&!kW  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), g.64Id  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), };&HhBc
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nStartPos,nEndPos,i); ]\CU9J|H8  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Qq#Ff\|4u(  
fileSplitterFetch.start(); ([:]T$0 #  
} 9$7&URwSDI  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), &w+;N5}3  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ]43alf F#  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", W8w3~  
nEndPos = " + nFileLength); Y,k(#=wg  
// fileSplitterFetch[nPos.length-1].start(); L|&'jH)  
wL4ZW8_  
3
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//等待子线程结束 duX0Mc.0P  
//int count = 0; e8$l0gzaD  
//是否结束while循环 ;wJ~haC  
boolean breakWhile = false; T}C2e! _O  
<,\ `Psa)N  
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while(!bStop) NF6X- ,cd  
{ 41u*w2j  
write_nPos(); &!ED# gs  
Utility.sleep(500); HbcOTd)=5  
breakWhile = true; Ls&+XlrX8  
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for(int i=0;i<nStartPos.length;i++) M70c{s`w5  
{ P Q7A~dw9  
if(!fileSplitterFetch.bDownOver) _`H.h6h  
{ )h#]iGVN}  
breakWhile = false; dXmV@ Noo  
break; ,Du@2w3Cq  
} lWW+5  
} [`d$X^<y;  
if(breakWhile) WzjL-a(  
break; -;^;2#](g  
F8H'^3`b`U  
+ :Vrip  
//count++; zbN
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//if(count>4) BT]ua]T+  
// siteStop(); /RGNAHtIi  
} ~4Pc_%&i  
"< v\M85&  
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System.err.println("文件下载结束！"); 9qK
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} n-$VUo  
catch(Exception e){e.printStackTrace ();} 9:5:`'b  
} =+Im*mgNn  
XAPYpBgm  
tAjx\7IX  
//获得文件长度 Ow3P-UzU3  
public long getFileSize() 9Y/L?km_(  
{ #O~XVuvF0  
int nFileLength = -1; $J.T$0pFa  
try{ scW'AJJq  
URL url = new URL(siteInfoBean.getSSiteURL()); M`vyTuO3SO  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); w5*Z!  
httpConnection.setRequestProperty("User-Agent","NetFox"); 6-B 9na  
;#TaZN  
$+cAg>  
int responseCode=httpConnection.getResponseCode(); t|V0x3X  
if(responseCode>=400) *:_P8G;  
{ Y#FO5O%W  
processErrorCode(responseCode); ][d,l\gu+s  
return -2; //-2 represent access is error eWvo,

4  
} HRB[GP+  
!"Q}R p  
iEIg
:  
String sHeader; |%1?3Mpn  
/R
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for(int i=1;;i++) ]"F5;p;y  
{ "CQw/qZw  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); f?56=& pHY  
//Utility.log(in.readLine()); zP!J/}z  
sHeader=httpConnection.getHeaderFieldKey(i); `TtXZ[gP}  
if(sHeader!=null) %+-C3\'  
{ ; |L<:x/  
if(sHeader.equals("Content-Length")) {_#yz\j  
{ Xl_Uz8Hp  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); K-eY|n  
break; 5,pSg  
} !:CJPM6j3  
} ]XA4;7  
else 0)!Ll*L!p  
break; M
+`Hg_#Q  
} ]"~51HQZ  
} ~u87H?  
catch(IOException e){e.printStackTrace ();} dQb.BOI)h  
catch(Exception e){e.printStackTrace ();} wGsRS[  
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Utility.log(nFileLength); [
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return nFileLength; O 5Nb  
} awewYf$li  
bEV<iZDq%  
^Q+i=y{W  
//保存下载信息（文件指针位置） SC &~s
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private void write_nPos() 27F~(!n  
{ qTQ!jN  
try{
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output = new DataOutputStream(new FileOutputStream(tmpFile)); H ?M/mGP  
output.writeInt(nStartPos.length); DI|:p!
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for(int i=0;i<nStartPos.length;i++) 5S{7En~zUE  
{ 8}e,%
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// output.writeLong(nPos); CjIu[S1%
 
output.writeLong(fileSplitterFetch.nStartPos); Q,h7Sk*  
output.writeLong(fileSplitterFetch.nEndPos); MZJ]Dwt]  
} p&-'|'![l  
output.close(); e`>{$t  
} _c$9eAe  
catch(IOException e){e.printStackTrace ();} x35cW7R}T_  
catch(Exception e){e.printStackTrace ();} {<>K]P~wD  
} qFQ8  
J?UQJ&!@O  
U$dh1;  
//读取保存的下载信息（文件指针位置） CSPKP#,B0[  
private void read_nPos() <"D=6jqZ  
{ CzCQFqXI  
try{ z+a%5J  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Em 6Qe  
int nCount = input.readInt(); xM[Vc  
nStartPos = new long[nCount]; iJ' xh n  
nEndPos = new long[nCount]; ^ci3F<?Q=  
for(int i=0;i<nStartPos.length;i++) 0Uk@\[1ox  
{ ;Vik5)D2D  
nStartPos = input.readLong(); @+F4YJmB?l  
nEndPos = input.readLong(); [Y
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} ~9)"!  
input.close(); 5 <wnva  
} :j')E`#   
catch(IOException e){e.printStackTrace ();} mGUO6>g  
catch(Exception e){e.printStackTrace ();} @yXfBML?]  
} ]ul$*  
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private void processErrorCode(int nErrorCode) zA+~7;7E  
{ CC\*?BKj"  
System.err.println("Error Code : " + nErrorCode); N,2s?Y_!  
} \)K^=jM  
 z@|GC_L  
7QKr_  
//停止文件下载 53-v|'9'  
public void siteStop() G7--v,R1x  
{ P0H6mn*  
bStop = true; kr$b^"Ku  
for(int i=0;i<nStartPos.length;i++) t5)+&I
2  
fileSplitterFetch.splitterStop(); J_Ltuso  
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} t#%R q  
} .s+aZwTMT  
//负责部分文件的抓取 F":r4`5D"K  
**FileSplitterFetch.java r]
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*/ !RyO\>:q  
package NetFox; H$G0`LP0/a  
n,$IfC"  
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import java.io.*; '47P|t  
import java.net.*; AU-n&uX  
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54 >-  
public class FileSplitterFetch extends Thread { Og=*R6i  
k} ]T;|h]  
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String sURL; //File URL >^XBa*4;Y  
long nStartPos; //File Snippet Start Position Hwo$tVa:=  
long nEndPos; //File Snippet End Position Fu&EhGm6  
int nThreadID; //Thread's ID nqwAQhzy(  
boolean bDownOver = false; //Downing is over PJcwH6m  
boolean bStop = false; //Stop identical gTA%uRBa  
FileAccessI fileAccessI = null; //File Access interface DjSbyXvrg  
[<'-yQ{l\  
V& C/Z}\  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException `--TP  
{ GnP|x}YM  
this.sURL = sURL; ?c0xRO%y  
this.nStartPos = nStart; ,V*%V;  
this.nEndPos = nEnd; (@iMLuewK  
nThreadID = id; 71vkyn@"  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ]E]2o  
} V+I|1{@i0  
C@jJ.^ <<  
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public void run() ChCrL[2  
{ S[7WW$lF  
while(nStartPos < nEndPos && !bStop) SM`w;?L:?  
{ s}N#n(  
}:Z#}8  
F <hJp,q9  
try{ `'V4PUe  
URL url = new URL(sURL); meOMq1  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Zh_|m#)  
httpConnection.setRequestProperty("User-Agent","NetFox"); )Tk1 QHU  
String sProperty = "bytes="+nStartPos+"-"; #!)n {
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httpConnection.setRequestProperty("RANGE",sProperty); I4&::y^C  
Utility.log(sProperty); %;.;>Y(-  
!qX_I db\  
,_"AT!r  
InputStream input = httpConnection.getInputStream(); K~22\G`  
//logResponseHead(httpConnection); JwJ7=P=c  
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byte[] b = new byte[1024]; :]J Ye*  
int nRead; hGiz)v~  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) +|tC'gCnV  
{ Unsogd  
nStartPos += fileAccessI.write(b,0,nRead); Yot?=T};3{  
//if(nThreadID == 1) R58-wUto  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Br`IW  
} b!)<-|IK  
/PLn+-  
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Utility.log("Thread " + nThreadID + " is over!"); L:9F:/G  
bDownOver = true; .w]GWL  
//nPos = fileAccessI.write (b,0,nRead);
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} j\m_o% 4  
catch(Exception e){e.printStackTrace ();} P{u0ftyX}  
} 9]e V?yoA8  
} _U/!4A  
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{#{DH?=^)u  
//打印回应的头信息 lg(bDKm  
public void logResponseHead(HttpURLConnection con) aXL{TD:]  
{ |m2X+s9  
for(int i=1;;i++) Q9Q|lO  
{ f4BnX(1u  
String header=con.getHeaderFieldKey(i); v'BZs   
if(header!=null) O)"gS!,  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); rta:f800z  
Utility.log(header+" : "+con.getHeaderField(header)); Y*!qG  
else D_x+
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break; EI^06q4x  
} Yb
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} (7r<''  
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public void splitterStop() Jej` ;I  
{ -e8}Pm "  
bStop = true; >$ e9igwe  
} q=#} yEG  
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} 65Cg]Dt71  
$ >EY
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/* PnoPbk[<  
**FileAccess.java nH<eR)0  
*//文件访问(定位，写) n-%s8aaVf  
package NetFox; g]c6&Y,#  
import java.io.*; qv@$ZLR  
M{*Lp6h  
? 8LXP  
public class FileAccessI implements Serializable{ $k2*[sn,  
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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 ,JEFGI{  
RandomAccessFile oSavedFile; V#`fs|e;y  
long nPos; WASU0
 
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public FileAccessI() throws IOException PoT`}-9  
{ %b"\bHH  
this("",0); pi ,eIm  
} L*~J%7  
iySRY^  
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public FileAccessI(String sName,long nPos) throws IOException  0gfA#|'  
{ oDU ;E  
oSavedFile = new RandomAccessFile(sName,"rw"); ]~E0gsq  
this.nPos = nPos; k0Uyf~p~  
oSavedFile.seek(nPos); {1b Zg  
} (4Zts0O\  
$9ky{T?YG  
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public synchronized int write(byte[] b,int nStart,int nLen) b%S62(qP  
{ H `(exa:w  
int n = -1; I:d[Q s  
try{ T"0,r$
3:  
oSavedFile.write(b,nStart,nLen);  z~>pVs
  
n = nLen; pe{;~-|6  
} _`pD`7:aI^  
catch(IOException e) =F;.l@:  
{ T.qNCJmB  
e.printStackTrace (); YR;^hs?  
} as>L[jyG/  
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return n; 6l4mS~/  
} b&5lYp"d  
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} }ga@/>Sl&  
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/* iT)z_  
**SiteInfoBean.java $]rj73p^tH  
*/ 
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package NetFox; {je-I9%OK  
"^1L'4'S  
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public class SiteInfoBean { uSR~@Lj ~  
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private String sSiteURL; //Site's URL Zw~
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private String sFilePath; //Saved File's Path k
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private String sFileName; //Saved File's Name Q pmsOp|  
private int nSplitter; //Count of Splited Downloading File H/"lAXfb  
(~J^3O]Fo  
kn/Ao}J74z  
public SiteInfoBean() _{ZqO;[u  
{//nSplitter的缺省值为5 d%0~c'D8a  
//default value of nSplitter is 5 &RTX6%'KY  
this("","","",5); S*sT] J`!  
} mSo_} je(  
XyOl:>%L!P  
fhCc! \  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) +d%L\^?F  
{ \{EpduwZ  
sSiteURL= sURL; V$uk6#  
sFilePath = sPath; @GvztVYo  
sFileName = sName; -> J_ ~  
this.nSplitter = nSpiltter; <2nZ&M4/s{  
A3ZY~s#Iv  
?SC[G-
b  
} A=
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public String getSSiteURL() a:_I
  
{ T_lsGu/  
return sSiteURL; hbcuK&  
} MBXBog7U  
JO@|*/mL  
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public void setSSiteURL(String value) W'on$mB5<  
{ ,p9i%i  
sSiteURL = value; 0j_bh,zG#  
} +GAf O0  
Z'k|u4ZC  
VG>vn`x>a  
public String getSFilePath() Q*XE h  
{ x[Wwq=~  
return sFilePath; aceZ3U>W  
} w\19[U
3  
n\ Hs@.  
> MH(0+B*  
public void setSFilePath(String value) ^Eo=W/   
{ W k}AmC  
sFilePath = value;
zY|klX})  
} -`Y:~q1
 
@K:N,@yq  
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public String getSFileName() W8g'lqc|  
{ 1+7GUSIb  
return sFileName; JO'>oFv_W  
} dgo3'ZO  
Bu]t*$  
?J,AB #+  
public void setSFileName(String value) d HJhFw  
{ 'r\ V.4  
sFileName = value; ,]5Ic.};p  
} %5*@l vy  
BtY%r7^o  
>Ng)k]G  
public int getNSplitter() pDhse2  
{  a1j.fA  
return nSplitter; &J!aw  
} dC1V-x10ju  
n& $^04+i  
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public void setNSplitter(int nCount) 3u33a"nL8  
{ Xes|[*Y!V  
nSplitter = nCount; 9,]5v+  
} [= "r<W0  
} aTzDew  
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J`*iZvW#Bx  
/* <:|3rfm#  
**Utility.java ~LQ[4h<J !  
*/ ggb|Ew  
package NetFox; ]8;n{ }X  
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>`jU`bR@  
public class Utility { 19q{6X`x  
4ujvD^  
,DnYtIERo  
public Utility() e&9F\e  
{ OJ4SbI  
ug`NmIQP  
5y4u5Tm-%  
} JmpsQ,,  
"gW7<ilw   
//线程睡眠 Rb}KZ+o"Z  
public static void sleep(int nSecond) -p-0;Hy  
{ pe&UQ C^  
try{ Bf4%G,o5  
Thread.sleep(nSecond); O3NWXe<  
} AAUyy :  
catch(Exception e) T{vR,  
{ <EO<x D=:  
e.printStackTrace (); ] q~<=  
} s4T}Bsr  
} jQj,q{eA  
9x`4
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//日志 %"A_!<n@*`  
public static void log(String sMsg) KbxR Lx]w  
{ ~9$X3.+  
System.err.println(sMsg); 5c-N0@\  
} sNU}n<J-  
g2p"LWex-  
BC\S/5~k  
public static void log(int sMsg) eR!G[Cw-  
{ /2NSZO  
System.err.println(sMsg); >[a<pm!  
} G\iyJSj[P  
} +'03>!V  
t"s5\;IJ  
:wgfW .w  
/* kB\kpW  
**TestMethod.java QYT
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*/ 3 EYiQ`  
package NetFox; V{Q kN7-  
[B6DC`M  
Jfg7\&|  
public class TestMethod { )%JD8;[Jq  
Yr&Ka:  
8V5a%2eV  
public TestMethod() aU<s<2O)  
{ ///xx/weblogic60b2_win.exe cBEHH4U  
try{ AZZRa69=  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); fnH3CE  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5);  U w Eiz  
SiteFileFetch fileFetch = new SiteFileFetch(bean); #s+X+fe  
fileFetch.start(); 0rzVy/Z(  
} kR6A3?[  
catch(Exception e){e.printStackTrace ();} F=&;Y@t  
vD=%`G[m  
t=dO  
} WD?Jk9_F  
*_)E6Y?9  
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public static void main(String[] args) !dv-8C$U  
{ C+l?k2  
new TestMethod(); vg^M
yn   
} k:P$LzIB  
} Vm!i  
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