http断点续传简单实现（java)

/* \O?#gW\tR  
**SiteFileFetch.java hHoc7  
*/ #]I:}Q51  
package NetFox; B$Jn|J"/6  
import java.io.*; 9VIsLk54^  
import java.net.*; ;W#G<M&n'  
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public class SiteFileFetch extends Thread { Tk/K7h^  
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SiteInfoBean siteInfoBean = null; //文件信息Bean )zt*am;  
long[] nStartPos; //开始位置 52*zX 3  
long[] nEndPos; //结束位置 ^zqz$G#  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 <?Fgm1=o  
long nFileLength; //文件长度 v}-'L#6  
boolean bFirst = true; //是否第一次取文件 BZsw(l4/0'  
boolean bStop = false; //停止标志 bn^^|i  
File tmpFile; //文件下载的临时信息 ;4XX8W1  
DataOutputStream output; //输出到文件的输出流 XLFJ?$)Tro  
~@R=]l"  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） }(J6zo9(x  
public SiteFileFetch(SiteInfoBean bean) throws IOException 1S\q\kz->D  
{ %
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siteInfoBean = bean; 9n!3yZVSe  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); H"I|dK:  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); u9m"{KnV  
if(tmpFile.exists ()) <H)h+?&~d  
{ ,[+gE\z{{u  
bFirst = false; W;IvR  
read_nPos();  7P]_03  
} ` M"Zq  
else R^dAwt`.D  
{ 2hf]XV\  
nStartPos = new long[bean.getNSplitter()]; f?[y-  
nEndPos = new long[bean.getNSplitter()]; W32mAz;  
} Ik=KEOz  
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} |!I#T  
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public void run() ngEjbCV+  
{ "v jFL9  
//获得文件长度 yBauK-7*c  
//分割文件 N+!{Bt*  
//实例FileSplitterFetch ^b;.zhp8;N  
//启动FileSplitterFetch线程 -YHlVz  
//等待子线程返回 ,/:#=TuYm  
try{ lpve Yz  
if(bFirst) d'^jekh  
{ |;{wy  
nFileLength = getFileSize(); E[2c`XFd8  
if(nFileLength == -1) &OGY?[n  
{ QS_"fsyN:  
System.err.println("File Length is not known!"); X,x{!  
} ^7TM.lE  
else if(nFileLength == -2) C/_W>H_   
{ h{J2CWJ  
System.err.println("File is not access!"); b
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} O>|Q Zd  
else A#2Fd7&  
{ n`0}g_\q  
for(int i=0;i<nStartPos.length;i++) 3boINmX  
{ @?G.6r~  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 8K6yqc H  
} 398}a!XM  
for(int i=0;i<nEndPos.length-1;i++) N\HOo-X  
{ WK/Byd.Z  
nEndPos = nStartPos[i+1]; (Pc:A!}  
} a,M7Bbx  
nEndPos[nEndPos.length-1] = nFileLength; <G\q/!@_  
} O)`R)MQ)  
} :%xiH%C>  
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/S\P=lcb  
//启动子线程 1/6G&RB  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; %{&yXi:mS  
for(int i=0;i<nStartPos.length;i++) Po(9BRd7  
{ \ tF><  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), rMfp%DMA  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Mh[;E'C6  
nStartPos,nEndPos,i);
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Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); {Z1j>h$  
fileSplitterFetch.start(); ui YZk3  
} q*?LXKi  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), PRWS[2[yk  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); #r#UO  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ^0ipM/Lg  
nEndPos = " + nFileLength); C:l /%  
// fileSplitterFetch[nPos.length-1].start(); hqD]^P>l1  
C{-e(G`Yd  
b)3dZ*cOJ  
//等待子线程结束 <k6Zx-6X<  
//int count = 0; ZnI_<iFR*  
//是否结束while循环 g"hm"m}i  
boolean breakWhile = false; a%7%NN*i  
jzdK''CHi  
Z-*L[  
while(!bStop) M7fw/i  
{ *s S7^OZ*  
write_nPos(); %W+*)u72(  
Utility.sleep(500); !d&K,k  
breakWhile = true; GO+cCNMa"  
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u! x9O8y  
for(int i=0;i<nStartPos.length;i++) +i4S^B/8i  
{ }O<=!^Y;A  
if(!fileSplitterFetch.bDownOver) 4nXS}bWf  
{ 3!,XR\`[  
breakWhile = false; }R;.~F  
break; Q
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} y5RcJM  
} 2}/Z.)^Q  
if(breakWhile) (
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break; 7Xw;TA  
# ~} 26  
bezT\F/\  
//count++; )d2<;c  
//if(count>4) k*w]a  
// siteStop(); Ky8sLm@  
} !\z:S?V  
B ;9^  
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System.err.println("文件下载结束！"); ~kD/dXt  
} (lTM5qC  
catch(Exception e){e.printStackTrace ();} 0 j:8Ve  
} wbyY?tH  
nz3j";d  
p'0jdb :S  
//获得文件长度 o6'I%Gs  
public long getFileSize() h*Rh:yCR>  
{ *}-X '_  
int nFileLength = -1; A{bt
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try{ qb]n{b2  
URL url = new URL(siteInfoBean.getSSiteURL()); UwvGw5)q  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); p&>*bF,  
httpConnection.setRequestProperty("User-Agent","NetFox"); D}>pl8ke~g  
68[3 /  
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int responseCode=httpConnection.getResponseCode(); %FDi7Rx  
if(responseCode>=400) +%OINMo.A  
{ O={4 >>F  
processErrorCode(responseCode); k?;A#L~  
return -2; //-2 represent access is error JN .\{ Y  
} +?w 7Nm`  
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String sHeader; }/n
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for(int i=1;;i++) wc*5s7_  
{ j&6,%s-M`a  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); GvF8S MO[x  
//Utility.log(in.readLine()); '_lyoVP  
sHeader=httpConnection.getHeaderFieldKey(i); zH0%; o}  
if(sHeader!=null) puF'w:I(  
{ 9z$]hl  
if(sHeader.equals("Content-Length")) Z3g6?2w6  
{ "o2p|2c  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); GpMKOjVm|  
break; o]t6u .L  
} HgvgO\`]  
} 0&mo1 k_U  
else @zL)R b%P$  
break; ! @{rkp  
} r Lg(J|^  
} vIF=kKl9,  
catch(IOException e){e.printStackTrace ();} Sf);j0G,D  
catch(Exception e){e.printStackTrace ();} w17\ \[  
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Utility.log(nFileLength); kT&-:: ^R  
,24NMv7  
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return nFileLength; ([R}s/)$  
} |5_bFB+&  
bZHuEh2w  
8c(}*,O/  
//保存下载信息（文件指针位置） bW(+
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private void write_nPos() ,d(F|5M:  
{ 8/,m8UOY  
try{ {hGr`Rh  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ! E`Tt[  
output.writeInt(nStartPos.length); vA2@Db}  
for(int i=0;i<nStartPos.length;i++) 6F6[w?   
{ \(Dq=UzQI  
// output.writeLong(nPos); l+Dl~o}  
output.writeLong(fileSplitterFetch.nStartPos); (#Z2  
output.writeLong(fileSplitterFetch.nEndPos); ,],"tzKtE  
} Fvf308[  
output.close(); S~d_SU~>`  
} IT! a)d  
catch(IOException e){e.printStackTrace ();} &I Iw>,,  
catch(Exception e){e.printStackTrace ();} 1mhX3  
} t j&+HC  
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//读取保存的下载信息（文件指针位置） a\S"d  
private void read_nPos() 5!$m3j_,]?  
{ O{zY(`[  
try{ )f-ux5  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); A
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int nCount = input.readInt(); kq6S`~J^R  
nStartPos = new long[nCount]; * t6XU  
nEndPos = new long[nCount]; %
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for(int i=0;i<nStartPos.length;i++) /ZqBO*]  
{ 1@q~(1-o  
nStartPos = input.readLong(); vCyvy^s-I  
nEndPos = input.readLong(); R$'4 d  
} m^rgzx19?  
input.close(); _I8L#4\(=  
} E/|]xKG  
catch(IOException e){e.printStackTrace ();} 5tT-[mQ*  
catch(Exception e){e.printStackTrace ();} s\i=-`  
} G;_QE<V~_  
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k@JDG]R<{  
private void processErrorCode(int nErrorCode) Mez;DKJ`  
{ &dF$:$'s  
System.err.println("Error Code : " + nErrorCode); Rn~FCj,-  
} 5W"nn  
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@*  
//停止文件下载 u.*@lGVW  
public void siteStop() LI_>fuv"8  
{ ^'.=&@i-  
bStop = true; 8:;_MBt  
for(int i=0;i<nStartPos.length;i++) bq[j4xH0X  
fileSplitterFetch.splitterStop(); *(Y
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2ME"=!&5  
} N(>a-a  
} CXks~b3SD  
//负责部分文件的抓取 g66=3c9</6  
**FileSplitterFetch.java ez=$]cln  
*/ 5%"$
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package NetFox; ?z%@;&  
/tl/%:U*.  
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import java.io.*; =Xh^@OR  
import java.net.*; {[G2{ijRz  
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public class FileSplitterFetch extends Thread { K]' 84
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String sURL; //File URL SQ|pH"  
long nStartPos; //File Snippet Start Position wLC!vX.
S  
long nEndPos; //File Snippet End Position wH=  
int nThreadID; //Thread's ID r`XIn#o  
boolean bDownOver = false; //Downing is over \s?OvqI:  
boolean bStop = false; //Stop identical V2sWcV?  
FileAccessI fileAccessI = null; //File Access interface ;ZXP*M9  
tW53&q\=  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 6eE%x?#  
{ In^MZ)?  
this.sURL = sURL; "}Kvx{L8  
this.nStartPos = nStart; dl;~-'0  
this.nEndPos = nEnd; p 2xOjS1  
nThreadID = id; Cj%SW <v|  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 D5fJuT-bp  
} W/ZmG]sZE  
#q`[(`Bx  
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public void run() '#$Y:/  
{ <h|XB}s+  
while(nStartPos < nEndPos && !bStop) VTk6.5!8  
{ ~ ui/Qf2|  
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;Q&38qI  
try{ ozH7c_ <  
URL url = new URL(sURL); W)JUMW2|  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); R5 47  
httpConnection.setRequestProperty("User-Agent","NetFox"); {9U<!  
String sProperty = "bytes="+nStartPos+"-"; @3KVYv,q  
httpConnection.setRequestProperty("RANGE",sProperty); BM=`zGh"  
Utility.log(sProperty); `?LQd2p  
ta"/R@ k*  
;tTM3W-h  
InputStream input = httpConnection.getInputStream(); 'c5#M,G~  
//logResponseHead(httpConnection); \eF5* {9  
%41dVnWB^4  
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byte[] b = new byte[1024]; -q' np0H  
int nRead; jUtrFl  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 16/+ O$#y  
{ 9\i;zpN\  
nStartPos += fileAccessI.write(b,0,nRead); q"ba~@<BEl  
//if(nThreadID == 1) T
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// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 1rh\X[@  
} Onb*nm  
 hh<5?1  
{dvrj<?  
Utility.log("Thread " + nThreadID + " is over!"); ##d\|r  
bDownOver = true; W7.O(s,32  
//nPos = fileAccessI.write (b,0,nRead); 9UTWq7KJ  
} c_clpMx=  
catch(Exception e){e.printStackTrace ();}  v'i"Q  
} LqIMU4Ex  
} J0zudbP  
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|t CD@M  
//打印回应的头信息 MV6%~T  
public void logResponseHead(HttpURLConnection con) 6-va;G9Fc  
{ qd{o64;|  
for(int i=1;;i++) pcXY6[#N  
{ HX\@Qws  
String header=con.getHeaderFieldKey(i); ;wND?:  
if(header!=null) 3U<\y6/  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 0h!2--Aur  
Utility.log(header+" : "+con.getHeaderField(header)); BF8n: }9U  
else @_^QBw0  
break; %Y%+K5;AZ  
} }u cqzdk#2  
} 4 q
}1  
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public void splitterStop() f^](D'L?D  
{ WS9n.opl}  
bStop = true; [W=%L:Ea  
} IcZ_AIjlk  
^% BD  
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} .vNfbYH(  
vW]Frb  
1Uz'=a  
/* !OWVOq8  
**FileAccess.java hKtOh  
*//文件访问(定位，写) 'KpCPOhfR  
package NetFox; D *W+0  
import java.io.*; dvxD{UH  
/-z_"G  
@iB**zR/  
public class FileAccessI implements Serializable{ ASY 
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GJWC}$#TY  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 /k<*!H]KSg  
RandomAccessFile oSavedFile; 8(ny^]v|  
long nPos; S<Q8kW:  
M['25[  
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public FileAccessI() throws IOException d|TRP,y  
{ gXI_S9z  
this("",0); v}A] R9TY  
} Y?%MPaN:  
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public FileAccessI(String sName,long nPos) throws IOException U#G uB&V  
{ S1uW`zQ!+_  
oSavedFile = new RandomAccessFile(sName,"rw"); *7oPM5J|v  
this.nPos = nPos; mkYM/*qyM&  
oSavedFile.seek(nPos); g*t.g@B<2  
} qMYR\4"$  
G39H@@ *O0  
?# >|P-4  
public synchronized int write(byte[] b,int nStart,int nLen) ^q"p8   
{ [ /*$?PXt  
int n = -1; ({D.oS  
try{ .6!]RA5!=  
oSavedFile.write(b,nStart,nLen); J&^r}6D  
n = nLen; 1w+OnJI?  
} JeMhiY}  
catch(IOException e) ,iCd6M{  
{ o"[P++qd  
e.printStackTrace (); L6BHh_*E  
} Q !5Tw  
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7qon:]b4  
return n; ERL(>)  
} X ~4^$x  
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} s .^9;%@$J  
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/* vtR<(tOu@  
**SiteInfoBean.java ^]'p927  
*/ *-Lnsi^7v  
package NetFox; ,qiS;2(  
9L%&4V}BIS  
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public class SiteInfoBean { 5gF}7D@  
JC{}iG6r+  
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private String sSiteURL; //Site's URL 'Twi @I  
private String sFilePath; //Saved File's Path '7>Vmr6  
private String sFileName; //Saved File's Name ] 5
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private int nSplitter; //Count of Splited Downloading File 'BAe>r_Pn  
po=*%Zs*T  
F xFK  
public SiteInfoBean() K!|=)G3.`  
{//nSplitter的缺省值为5 p: sn>Y  
//default value of nSplitter is 5 ;oh88,*'  
this("","","",5); Q C~~  
} "4g1I<  
i+(`"8W  
"R*B~73  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) `<HY$PAe  
{ \Zoo9Wy  
sSiteURL= sURL; !"2OcDFx  
sFilePath = sPath; \nkqp   
sFileName = sName; Km+29  
this.nSplitter = nSpiltter; fhH* R*4  
$ }B"u;:SU  
H/)=  
} A ,LAA$  
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@GnsW;$*~.  
public String getSSiteURL() 8>pFpS  
{ pKEMp&geo  
return sSiteURL; nkhM1y  
} BD4.sd+H,  
xR#hU;E}  
(Egykh>  
public void setSSiteURL(String value) /6gRoQ%j  
{ L@a-"(TN+
 
sSiteURL = value; \SLYqJ~m  
} 9D<^)ShY  
WK;p[u?~xi  
{GWcw<g.B  
public String getSFilePath() v{% /aw  
{ '2# 0UdG  
return sFilePath; =[1W.Zt  
} c |C12b[  
uT-WQ/id  
}a<MVG:>SF  
public void setSFilePath(String value) ,nHz~Xi1t  
{ +nJ}+|@
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sFilePath = value; G)<k5U4  
} \re.KB#R  
RtqW!ZZ:H  
*D<sk7  
public String getSFileName() }FM<uBKW  
{ Ccc6 ko_  
return sFileName; )@K|Co  
} Z@I%ppd  
nosEo?{  
m};
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public void setSFileName(String value) -w@fd]g  
{ PA
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sFileName = value; c,D'Hl6(%  
} ' >\*  
p{-1%jQ}]  
A<TJ3Jp]  
public int getNSplitter() ![vc/wuf  
{ 1H[lf B  
return nSplitter; |23 }~c,  
} nI
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public void setNSplitter(int nCount) jG.*tuf  
{ RMi 2Ip  
nSplitter = nCount; LXXxwIBS  
} j|[s?YJl  
} zJ9,iJyuD  
[ B (lJz  
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/* 4h~Oj y16&  
**Utility.java L7jz^g^  
*/ pt0H*quwI  
package NetFox; ol[{1KT{  
J,~)9Kh$  
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public class Utility { 2l!"OiB.P  
*|=&MU*+  
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public Utility() tICxAp:  
{ '[juPI(!  
eq@ v2o7  
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} Eui;2P~  
71A{"  
//线程睡眠 \7C >4  
public static void sleep(int nSecond) VJ$C)0xQA  
{ T\WNT#My  
try{ #qn)Nq(  
Thread.sleep(nSecond); F)%;
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} DC$ S. {n  
catch(Exception e) 3>jz3>v@  
{ dT|z)-Z`  
e.printStackTrace (); UfkRY<H  
} #|CG %w  
} PO}Q8Q3  
h:GOcLYM@X  
//日志 3] @<.  
public static void log(String sMsg) RB\WttI  
{ W4#:_R,&,  
System.err.println(sMsg); 1mjv~W  
} HOUyB's'  
/f6]XP\'`+  
>WD^)W fa  
public static void log(int sMsg) I{Kc{MXn  
{ z)]EB6uRg  
System.err.println(sMsg); TY#1Z )%  
} i5wA=K_  
} tL
).f:?  
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Sm1bDa\!=  
/* Dr2h-  
**TestMethod.java JA)gM  
*/ E8j9@BHU[r  
package NetFox; i;tA<-$-  
3jn@ [ m  
%-*vlNC)  
public class TestMethod { *K98z ?  
tEEhSG)s%  
KW;xlJz(j  
public TestMethod() a-}%R  
{ ///xx/weblogic60b2_win.exe 54;iLL  
try{ |knP  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); :^*V[77  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); vV'^HD^v  
SiteFileFetch fileFetch = new SiteFileFetch(bean); iwVra"y  
fileFetch.start(); K;97/"  
} Xo*$|9[.  
catch(Exception e){e.printStackTrace ();} R5i8cjKZ?w  
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mvL'l)  
} feopO j6~+  
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ft*0?2N~  
public static void main(String[] args) N Hh  
{ M!hby31  
new TestMethod(); $%E9^F  
} ,mX|TI<*  
} A8RT3OiXA  
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