http断点续传简单实现（java)

/* s
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**SiteFileFetch.java S63Zk0(25  
*/ )Q)qz$h@  
package NetFox; BFLef3~.0  
import java.io.*; 8;PkuJR_]  
import java.net.*; yNTd_XPL  
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&W `xZyb3  
public class SiteFileFetch extends Thread { UZZJtQt  
9KSi-2?H  
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SiteInfoBean siteInfoBean = null; //文件信息Bean g7oY
1;  
long[] nStartPos; //开始位置 %H{p&ms  
long[] nEndPos; //结束位置 U"oNJ8&%|  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 h}bfZL  
long nFileLength; //文件长度 E?m~DYnU  
boolean bFirst = true; //是否第一次取文件 q76POytV|  
boolean bStop = false; //停止标志 'CLZ7pV  
File tmpFile; //文件下载的临时信息 qnm_#!&uHT  
DataOutputStream output; //输出到文件的输出流  ;C]Ufk  
h}b:-a  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） xNz(LZ.c  
public SiteFileFetch(SiteInfoBean bean) throws IOException #-hO\ QdC  
{
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siteInfoBean = bean; x2"iZzQlD  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); LQ0/oYmNc  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); yNu_>!Cp5  
if(tmpFile.exists ()) {.Tx70kn  
{ ^l &lwSRVt  
bFirst = false; 6( HF
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read_nPos(); [P$Xr6#  
} n:j'0WW  
else %>_[
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{ GAGS-G#  
nStartPos = new long[bean.getNSplitter()]; f^c+M~\JKj  
nEndPos = new long[bean.getNSplitter()]; E-LkP;  
} M .#}  
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} i1iP'`
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public void run() *MF9_V)8V  
{ gGqrFh\  
//获得文件长度 p|UL<M9{a]  
//分割文件 Aoa8Q E  
//实例FileSplitterFetch H`EhsYYK  
//启动FileSplitterFetch线程 gY}In+S  
//等待子线程返回 gesbt  
try{  :Mx  
if(bFirst) 'uPAG;)m  
{ dBWny&  
nFileLength = getFileSize(); b F=MQ  
if(nFileLength == -1) s.3"2waZ=T  
{ _\!]MV  
System.err.println("File Length is not known!"); \j8vf0c5b  
} t;O)  
else if(nFileLength == -2)  tm1=  
{ pP
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System.err.println("File is not access!"); z2=bbm:  
} V>6klA}o
 
else $ {yct  
{ 4vhf!!1  
for(int i=0;i<nStartPos.length;i++)
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{ -Cf)`/  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); X1o",,N^M  
} 7*:zN
  
for(int i=0;i<nEndPos.length-1;i++) y]9R#\P/  
{ \i.]
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nEndPos = nStartPos[i+1]; dab]>% M  
} ]>3Y~KH(  
nEndPos[nEndPos.length-1] = nFileLength; )|gw5N4;  
} 6jE.X  
} &OR(]Wt0  
N['DqS =  
43=v2P0=Tj  
//启动子线程 W/'1ftn?D  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 0cG'37[  
for(int i=0;i<nStartPos.length;i++) bWPsfUn#  
{ Xfiwblg  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ]HKt7 %,  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), {q>%Sr]9  
nStartPos,nEndPos,i); 1\hLwG6Jj  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 0Tj,TF  
fileSplitterFetch.start(); CTMC78=9}  
} Nc[@QC{  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), LF|0lAr  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ^:9a1{L[  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", r"H::A  
nEndPos = " + nFileLength); 1;B~n5C.   
// fileSplitterFetch[nPos.length-1].start(); \aSP7DzqQ  
{kpad(E  
)g5?5f;  
//等待子线程结束 ;0DoZ  
//int count = 0; 84ij4ZYe  
//是否结束while循环 tBo\R?YRs  
boolean breakWhile = false; 1M ?BSH{  
-cqE^qAdX  
 Y@,iDQ  
while(!bStop) NAYLlW}A  
{ *V>?m6y/  
write_nPos(); '%$Vmf)=  
Utility.sleep(500); vPkLG*d8  
breakWhile = true;
}YwaN'3p!  
1?@HOu  
>%/x~UFc5  
for(int i=0;i<nStartPos.length;i++) yT^x0?
U  
{ CmEqo;Is  
if(!fileSplitterFetch.bDownOver) tE*BZXBlm  
{ ||+~8z#+,  
breakWhile = false;
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break; 8SRR)O[)}  
} ]n^iG7aB?  
} xoZm,Pxd  
if(breakWhile) @ @[xTyA  
break; ^eW<-n@^  
BabaKSm}LP  
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//count++; Nd8>p.iqO  
//if(count>4) QM,#:m1o  
// siteStop(); {}$9 70y  
} /=2aD5r  
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*'@Oo  
System.err.println("文件下载结束！"); ;lObqs*?
>  
} <2U#U;  
catch(Exception e){e.printStackTrace ();} ;m7V]h? R  
} >$q   
fWHvVyQ.  
17hoX4T  
//获得文件长度 fCt|8,-H  
public long getFileSize() NcA `E_3  
{ ljFq;!I5  
int nFileLength = -1; 2z>-H595az  
try{ ;"dX]":  
URL url = new URL(siteInfoBean.getSSiteURL()); }*fBHzNN  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); .n:Q~GEL  
httpConnection.setRequestProperty("User-Agent","NetFox"); sXVl4!=l6  
i>
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int responseCode=httpConnection.getResponseCode(); -K{R7  
if(responseCode>=400) "vGh/sXW  
{ H cmW  
processErrorCode(responseCode); 1>(EvY}Y\  
return -2; //-2 represent access is error :7e*- '  
} gt{kjrTv&  
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AVT% AS  
String sHeader; ^'QO!{7f  
%.Y5%TyP  
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for(int i=1;;i++) ~J\qkQ  
{ _8G w Mj  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); bBIh}aDN  
//Utility.log(in.readLine()); Hf4_zd  
sHeader=httpConnection.getHeaderFieldKey(i); {Y~>&B5  
if(sHeader!=null) }`=7%b`-?  
{ e=;A3S  
if(sHeader.equals("Content-Length")) h'y"`k-  
{ yr
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nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Vh-8pFt  
break; HT<p=o'$Z  
} =O}I{dNKZV  
} ^0]0ss;##R  
else `gSMb UgF  
break; Es>' N3A z  
} 6Bq_<3P_  
} 5CK+\MK  
catch(IOException e){e.printStackTrace ();} oh5'Isb$  
catch(Exception e){e.printStackTrace ();} sL@\,]Y  
}c G)$E  
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Utility.log(nFileLength); |>Q>d8|k  
~n=DI/AJ@-  
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return nFileLength; i1evB9FZ1z  
} $J1`.Q>)4  
y._'o7%  
dD,}i$  
//保存下载信息（文件指针位置） bi8_5I[  
private void write_nPos() j]Gn\QF  
{ !Z_+H<fi+I  
try{ e!6yxL*[@[  
output = new DataOutputStream(new FileOutputStream(tmpFile)); !wp1Df[  
output.writeInt(nStartPos.length); =$OGHc  
for(int i=0;i<nStartPos.length;i++) suEK;Bk9  
{ bM?gAY]mB8  
// output.writeLong(nPos); &S4*x|-C&  
output.writeLong(fileSplitterFetch.nStartPos); Fk=SkSky  
output.writeLong(fileSplitterFetch.nEndPos); ;nSF\X(;{  
} 7z?;z<VJ  
output.close(); |d0ZB_ci  
} Kx9u|fp5  
catch(IOException e){e.printStackTrace ();} E2DfG^sGV  
catch(Exception e){e.printStackTrace ();} YR'F]FI  
} ]:e_Y,@  
izP)t  
]bds~OY5 U  
//读取保存的下载信息（文件指针位置） l"ms:v  
private void read_nPos() fkI 5~Y|  
{ \'~ E%=Q  
try{ )tG. 9"<  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Q`F1t  
int nCount = input.readInt(); k;\gYb%L  
nStartPos = new long[nCount]; \2@J^O1,  
nEndPos = new long[nCount]; 1L,L/sOwB&  
for(int i=0;i<nStartPos.length;i++) R-%6v2;ry  
{ >YI Vi4''  
nStartPos = input.readLong(); !Cgj >=  
nEndPos = input.readLong(); _?-oPb  
}
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input.close(); 5W)ST&YPL*  
} Kk^*#vR  
catch(IOException e){e.printStackTrace ();} K]|UdNo  
catch(Exception e){e.printStackTrace ();} V'9.l6l   
} gqS9{K(f  
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private void processErrorCode(int nErrorCode) I|rb"bG  
{ i"&FW&W  
System.err.println("Error Code : " + nErrorCode); "3^tVX%$\[  
} [wQ48\^  
'=0}2sF>  
\Th<7WbR6#  
//停止文件下载 1(DiV#epG  
public void siteStop() L/"MRQ"  
{ 1<ag=D`F_"  
bStop = true; F
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for(int i=0;i<nStartPos.length;i++) 6*i**  
fileSplitterFetch.splitterStop(); `XxnQng  
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{ b$"SIg1E  
} ?=&; A  
} m,)s8_a  
//负责部分文件的抓取 Ay(p~U;gN*  
**FileSplitterFetch.java *73gp  
*/ 6qT@M0)i  
package NetFox; F` ybe\  
6:5K?Y
o  
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import java.io.*; 9rEBq&
 
import java.net.*; ~ *&\5rPb  
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public class FileSplitterFetch extends Thread {
:7K a4  
m?(8T|i  
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String sURL; //File URL B[Lm}B[  
long nStartPos; //File Snippet Start Position M FIb-*wT  
long nEndPos; //File Snippet End Position I/7!5
Z*  
int nThreadID; //Thread's ID t^'nh 1=  
boolean bDownOver = false; //Downing is over E !!,JnU  
boolean bStop = false; //Stop identical M">v4f&K1!  
FileAccessI fileAccessI = null; //File Access interface jz8u'y[n7  
k ]NZ%.  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException AA5G`LiT  
{ Um+_S@h  
this.sURL = sURL; DZ|*hQU>K  
this.nStartPos = nStart; L"ho|v9:  
this.nEndPos = nEnd; `N\ ^JAGW  
nThreadID = id; :{a< ~n`  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 pyhXET '  
}
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public void run() "VZ1LVI  
{ y`RzcXblIZ  
while(nStartPos < nEndPos && !bStop) dgP eH8_  
{ NQqw|3  
)M0`dy{1  
^BF}wQb:j  
try{ [-\Y?3  
URL url = new URL(sURL); ]r;rAOWVV  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); :^y!z1\2(7  
httpConnection.setRequestProperty("User-Agent","NetFox"); lgews"  
String sProperty = "bytes="+nStartPos+"-"; Q:q0C  +T  
httpConnection.setRequestProperty("RANGE",sProperty); kgo#JY-4  
Utility.log(sProperty); dBI-y6R  
Y|R=^ =d\  
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InputStream input = httpConnection.getInputStream(); m%L!eR  
//logResponseHead(httpConnection); }<WJR Y6j  
3l=q@72  
@V:K]M 5  
byte[] b = new byte[1024]; Wx0i_HFR  
int nRead; h@`Rk   
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) O=A R`r#u  
{ |5vcT,A  
nStartPos += fileAccessI.write(b,0,nRead); <ww D*t  
//if(nThreadID == 1) n~62
9&  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); v\
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} -H%v6E%yh  
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(}b~}X9  
Utility.log("Thread " + nThreadID + " is over!"); g!^N#o  
bDownOver = true; ~IZ-:?+S^  
//nPos = fileAccessI.write (b,0,nRead); +,spC`M6h  
} N1'"7eg/  
catch(Exception e){e.printStackTrace ();} ^ =C>  
} O::FB.k  
} jzf
~n~  
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<.)=CK  
//打印回应的头信息 c';~bYZ  
public void logResponseHead(HttpURLConnection con) d~8U1}dP  
{ =>'8<"M5z  
for(int i=1;;i++) `sm Cfh}j6  
{ M!6Fnj  
String header=con.getHeaderFieldKey(i); >n,_Aj c  
if(header!=null) Q+1ot,R  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 8fqabR  
Utility.log(header+" : "+con.getHeaderField(header)); XKGiw 2 C  
else {v*4mT  
break; |V5BL<4  
} K
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} P8c_GEna  
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public void splitterStop() FJ84'T\~  
{ bbjba36RO  
bStop = true; JM;bNW8  
} eP~
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} 4PVg?  
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/K!)}f(6  
/* 3@=<4$  
**FileAccess.java #<Y.+:  
*//文件访问(定位，写) Q%O9DCi  
package NetFox; aX.BaK6I  
import java.io.*; KJFQ)#SW!  
p>)1Z<D"a  
2- L-=0  
public class FileAccessI implements Serializable{ #:" ]-u^  
(~G*'/)  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 @zS/J,:v}  
RandomAccessFile oSavedFile; W\[E  
long nPos; P{dR pH|  
&3/`cl[+  
=-!jm? st*  
public FileAccessI() throws IOException q5g_5^csM{  
{ HZ<#H3_ix  
this("",0); NATi)A"TZ  
} :(enaHn#~  
.U(6])%;@  
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public FileAccessI(String sName,long nPos) throws IOException 5V<6_o  
{ 9y\nO)\Tv  
oSavedFile = new RandomAccessFile(sName,"rw"); w8D8\`i!"  
this.nPos = nPos; _dd_Z40R  
oSavedFile.seek(nPos); Oi?Q^ISxP  
}
TJNE2  
~^.,Ftkb@7  
{Q/@Y.~<  
public synchronized int write(byte[] b,int nStart,int nLen) 08
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{ ^I/(9KP#  
int n = -1; -rsS_[$2  
try{ cMi9 Z]  
oSavedFile.write(b,nStart,nLen); `T[yyOL/  
n = nLen; [vtDtwL  
} ?bd!JW bg`  
catch(IOException e) Mxz X@GBX  
{ ,~;`@  
e.printStackTrace (); 5%S5*c6BD  
} rKPsv*w  
}c/#WA|b  
QPVr:+\B{  
return n; _`Kh8G {e  
} ~b8.]Z^  
bY`Chb.  
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} |QzJHP @  
' Sd&I:
?  
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/* _BG`!3U+  
**SiteInfoBean.java @lB1t= D  
*/ A f?&VD4K  
package NetFox; XF{2'x_R  
LzXIqj'H7T  
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public class SiteInfoBean { yMNOjs'c {  
j+<!4 0#  
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private String sSiteURL; //Site's URL Y\!:/h]E&  
private String sFilePath; //Saved File's Path "~C\Z} ;  
private String sFileName; //Saved File's Name /XRgsF  
private int nSplitter; //Count of Splited Downloading File ^umHuAAE  
Ahd{f!  
M]\"]H?  
public SiteInfoBean() R U[  
{//nSplitter的缺省值为5 &m(eMX0lU  
//default value of nSplitter is 5 5NSXSR9c  
this("","","",5); ziW[qH {  
} 2b {Y1*  
EI9Yv>7d{  
\l6mXIn=>  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ~$a%& ]\  
{ ^1}ffE(3>  
sSiteURL= sURL; +&AU&2As  
sFilePath = sPath; u@wQ )^  
sFileName = sName; bv[*jr;45  
this.nSplitter = nSpiltter; Fo"'[`  
0A~f ^  
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} Rx<[bohio  
$AFiPH9  
e ]>{
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public String getSSiteURL() u*;53 43  
{ "2"*3R<Y  
return sSiteURL; )fZ5.W8UE]  
} JvUHoc$sI  
Us9$,(3  
BJ/#V)  
public void setSSiteURL(String value) 9.goO|~B~  
{ OQX ek@~2  
sSiteURL = value; `~t$k7wm=  
} Pb D|7IM  
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public String getSFilePath()
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@,  
{ QQjMC'  
return sFilePath; 6ud<B  
} EVmE{XlD;  
`V ++})5v  
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public void setSFilePath(String value) _jb"@TY  
{ J2#=`|t"  
sFilePath = value; 13{"sY:PT#  
} {&(bKQ  
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+ACV,GG  
public String getSFileName() ;v+CQx  
{ e;}5~dSi  
return sFileName; >Q\H1|?  
} ELNA-ZKp  
J=]w$e ?.P  
Zr2QeLQC(  
public void setSFileName(String value) FkECY  
{ B 9]sSx  
sFileName = value; {78*SR  
} {K0T%.G  
uJp}9B60_  
-+I! (?  
public int getNSplitter() <F.Ol/'h  
{ 7#|NQ=yd  
return nSplitter; Sdt2D  
} &akMj@4;R  
f&cG;Y  
3yD5u  
public void setNSplitter(int nCount) |-aj$u%~  
{ 1aMBCh<}JN  
nSplitter = nCount; |QgXSe7  
} ;%z0iZmg  
} 0Rk'sEX,  
01q7n`o#zf  
@%cJjZ5y  
/* "RX?"pB  
**Utility.java {}^ELw  
*/ LA@}{hU  
package NetFox; x}>tX
  
u!`C:C'  
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public class Utility { b~1p.J4  
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public Utility() hA\8&pI;  
{ =
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/eMZTh*1P  
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0  
} %Z5k8  
?RzT0HRd  
//线程睡眠 X9gC2iSs]  
public static void sleep(int nSecond) Z "=(uwM  
{ dO//  
try{ yEqmB4^-  
Thread.sleep(nSecond); yaR;  
} V=*J9~K  
catch(Exception e) }Voh5*$E`  
{ <d5vVn  
e.printStackTrace (); I!<v$  
} Qy/bzO  
} c_
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9G8QzIac  
//日志 EH "g`r  
public static void log(String sMsg) M>J ADt_]  
{ t5Mo'*j =  
System.err.println(sMsg); d$,i?d,  
} -pGt;  
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{n{}Y.  
public static void log(int sMsg) dGteYt
_F  
{ 3ElpS^2W  
System.err.println(sMsg); l=]vC +mU  
} XZ&v3ul  
} Yr=mLT|JN  
1;gSf.naG  
2!otVz!Mh  
/* ">QY'r  
**TestMethod.java uW
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*/ QPcB_wUqu  
package NetFox; >oNk(. %  
Z%{f[|h9}  
GDB>!ukg  
public class TestMethod { U44H/5/  
+=k|(8Js#  
*vO'Z &  
public TestMethod() oX4uRc7wR  
{ ///xx/weblogic60b2_win.exe GKtQ>39B  
try{ 5#o,]tP  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); (*x"6)`  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); k0IU~y%  
SiteFileFetch fileFetch = new SiteFileFetch(bean); `~]ReJ!X%  
fileFetch.start(); fx-*')  
} bC{8yV=)  
catch(Exception e){e.printStackTrace ();}  :Y
3?,  
m'B6qy!}6  
MX0B$yc$  
} WLl9>v^1  
j1
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public static void main(String[] args) Wd5t,8*8  
{ UIj/Id  
new TestMethod(); dZgfls  
} NLGr=*dq  
} ^e,RM_.  
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