http断点续传简单实现（java)

/* aL\PGdgO  
**SiteFileFetch.java lf`{zc r:  
*/ B9_X;c  
package NetFox; (' (K9@}  
import java.io.*; N@4w! HpJ  
import java.net.*; "m):Y;9iQ?  
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public class SiteFileFetch extends Thread { I.(,hFx;  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 5+4IN5o]=  
long[] nStartPos; //开始位置 -vo})lO  
long[] nEndPos; //结束位置 vQG5*pR*w  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 zy?|ODM  
long nFileLength; //文件长度 b<[Or^X ]  
boolean bFirst = true; //是否第一次取文件 5+0gR &|j  
boolean bStop = false; //停止标志 [-1^-bb  
File tmpFile; //文件下载的临时信息 4/~E4"8  
DataOutputStream output; //输出到文件的输出流 x3=A:}t8  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ,$L4dF3  
public SiteFileFetch(SiteInfoBean bean) throws IOException aH(J,XY  
{ S/hQZHZHg,  
siteInfoBean = bean; .&iawz  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); #<"~~2?  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); w>&aEv/f  
if(tmpFile.exists ()) / y40(l?  
{ 8P\G
}  
bFirst = false; 5X$jl;6  
read_nPos(); fCn^=8KOZ  
} r| wS<cA2  
else ij`w} V  
{ ea2ayT  
nStartPos = new long[bean.getNSplitter()]; r EE1sy/#  
nEndPos = new long[bean.getNSplitter()]; wo{gG?B  
} )gUR@V>e2  
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} LKB$,pR~1l  
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public void run() OX0%C.K)hZ  
{ i v38p%Zm  
//获得文件长度 :uS\3toj  
//分割文件 :gibfk]C  
//实例FileSplitterFetch /)>3Nq4Zx  
//启动FileSplitterFetch线程 Ms#M+[a  
//等待子线程返回 "Qc7dRmSxm  
try{ 1~_{$5[X?  
if(bFirst) #$07:UJ  
{ B)g[3gQ  
nFileLength = getFileSize(); h 0Q5-EA  
if(nFileLength == -1) .o^l z 9:  
{ OU_g
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System.err.println("File Length is not known!"); M#6W(|V/  
} 7hcYD!DS  
else if(nFileLength == -2) kd(8
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{ O"9\
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System.err.println("File is not access!"); oxA<VWUNT
 
} zT]8KA   
else Af2( 5]  
{ e{K 215  
for(int i=0;i<nStartPos.length;i++) ;7V%#-  
{ L|7R9+ZG  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); prF%.(G2)  
} g3/W=~r  
for(int i=0;i<nEndPos.length-1;i++) 3z?> j]  
{ L|xbR#v  
nEndPos = nStartPos[i+1]; {rw|#Z>A  
} ;bib/  
nEndPos[nEndPos.length-1] = nFileLength; I"<\<^B<  
} E6ElNgL  
} t\,PB{P
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//启动子线程 K7:)nv E  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; )9`qG:b'  
for(int i=0;i<nStartPos.length;i++) ,T$U'&;  
{ xF'EiX~  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), zKJ#`OhT  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), )23H1  
nStartPos,nEndPos,i); Ckuh:bs  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); x2\qXN/R  
fileSplitterFetch.start(); [!#L6&:a8  
} 6Y?|w3f   
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ;))+>%SGCt  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); l4YJ c  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", dOH&  
nEndPos = " + nFileLength); P* BmHz4KL  
// fileSplitterFetch[nPos.length-1].start(); k)=s>&hl  
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//等待子线程结束 rcG"o\g@+  
//int count = 0; CxW>~O:  
//是否结束while循环 T_5H&;a  
boolean breakWhile = false;
mL{6L?  

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while(!bStop) %pL''R9VF  
{ .g<DD)`  
write_nPos(); #f]SK[nR  
Utility.sleep(500); Moza".fiN  
breakWhile = true; wc4{)qDE  
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for(int i=0;i<nStartPos.length;i++) s*]}QmRpr  
{ KRRdXx\~  
if(!fileSplitterFetch.bDownOver) qq
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{ oAeUvmh  
breakWhile = false; 2uW; xfeY  
break; 0IBSRFt$g&  
} (iX+{a%"  
} Y\8)OBZ  
if(breakWhile) Om2d.7S  
break; ?NsW|w_  
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//count++; 0~/_|?]`7  
//if(count>4) 7[XRd9a5(  
// siteStop(); +\ .Lp 5  
} jm/`iXnMf  
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System.err.println("文件下载结束！"); 0 /U{p,r6`  
} Kis
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catch(Exception e){e.printStackTrace ();} i<Zc"v;  
} BW*rIn<?G  
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//获得文件长度 ENs&RZ;  
public long getFileSize() t-bB>q#3>  
{ UySZbmP48  
int nFileLength = -1; 7~.9=I'A  
try{ V {ddr:]
4  
URL url = new URL(siteInfoBean.getSSiteURL()); Dp-z[]})1  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ]Q)OL  
httpConnection.setRequestProperty("User-Agent","NetFox"); DsCcK3 k  
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int responseCode=httpConnection.getResponseCode(); JP[K;/  
if(responseCode>=400) y}ev ,j  
{ >U27];}y  
processErrorCode(responseCode); fJ!R6D  
return -2; //-2 represent access is error >!1-lfa8
 
} vV-`jsq20H  
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String sHeader; ]jp6k<KF  
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for(int i=1;;i++)
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{ R8Fv{7]c  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); #?- wm  
//Utility.log(in.readLine()); Q sCheHP  
sHeader=httpConnection.getHeaderFieldKey(i); B*Dz{a^.:  
if(sHeader!=null) oQ[f,7
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{ ;+
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if(sHeader.equals("Content-Length")) v;D~Pa  
{ YO}<Ytx  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); /!XVHkX[  
break; LBDjIpR6  
} HvJs1)Wo&  
} _ *Pf  
else +Q"4Migbe@  
break; FP4P|kl/9'  
} 5D//*}b,  
} 7Kxp=-k  
catch(IOException e){e.printStackTrace ();} 3{sVVq5Y  
catch(Exception e){e.printStackTrace ();} T'Dv.h  
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Utility.log(nFileLength); G mA< g  
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return nFileLength; |[b{)s?x  
} t!7-DF|N  
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//保存下载信息（文件指针位置） ^v7gIC  
private void write_nPos() 5">Z'+8  
{ D_zZXbNc  
try{ suDQ~
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output = new DataOutputStream(new FileOutputStream(tmpFile)); R.yvjPwJ  
output.writeInt(nStartPos.length); V+9 MoT?8  
for(int i=0;i<nStartPos.length;i++) CB}2j  
{ SSMHoJGm  
// output.writeLong(nPos); J)p l|I  
output.writeLong(fileSplitterFetch.nStartPos); q9s=~d7  
output.writeLong(fileSplitterFetch.nEndPos); Jij*x>K>y  
} T</F 0su|  
output.close(); 6?c7$Y  
} p9{mS7R9T  
catch(IOException e){e.printStackTrace ();} )MTO
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catch(Exception e){e.printStackTrace ();} #Ki[$bS~6  
} 28d'7El$  
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//读取保存的下载信息（文件指针位置） m^;f(IK5  
private void read_nPos() Q*ft7$l&  
{ }b.%Im<3R  
try{ v"Es*-{B  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); U z>+2m(  
int nCount = input.readInt(); s|r3Gv|G  
nStartPos = new long[nCount]; h>m"GpF x  
nEndPos = new long[nCount]; :,6\"y-  
for(int i=0;i<nStartPos.length;i++) _E.>`Q  
{ V)N%WXG  
nStartPos = input.readLong(); kc&U'&RgY  
nEndPos = input.readLong(); \(2sW^fY  
} sD#.Oq4&]y  
input.close(); .U]-j\  
} 49HZ2`Y  
catch(IOException e){e.printStackTrace ();} pIqeXY  
catch(Exception e){e.printStackTrace ();} c'yxWZEv  
} nZYBE030  
/f;~X"!  
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private void processErrorCode(int nErrorCode) KJ4.4Zq{c  
{ P( 8OQL:  
System.err.println("Error Code : " + nErrorCode); Qq|57X)P*  
} FVJGL  
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2g! +<YZ~  
//停止文件下载 j|#Bo:2km  
public void siteStop() 9p(.A$  
{ %._.~V  
bStop = true; H"WprHe  
for(int i=0;i<nStartPos.length;i++) c9h6C  
fileSplitterFetch.splitterStop(); Wvf ^N(  
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} z-)O9PV  
} 1yu4emye4  
//负责部分文件的抓取 [`7ThHX  
**FileSplitterFetch.java mc\"yC
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*/ B^^#D0<  
package NetFox; }-=|^  
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import java.io.*; 5$C-9  
import java.net.*; T9  
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public class FileSplitterFetch extends Thread { $qj2w"'  
I b5rqU\  
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String sURL; //File URL Er?&Y,o  
long nStartPos; //File Snippet Start Position r_A$DaC]  
long nEndPos; //File Snippet End Position vx5Zl&6r  
int nThreadID; //Thread's ID ~Z'?LV<t  
boolean bDownOver = false; //Downing is over )+9Uoe~6  
boolean bStop = false; //Stop identical i=2N;sAl  
FileAccessI fileAccessI = null; //File Access interface }0Ed]  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException }@d@
3  
{ }k.Z~1y  
this.sURL = sURL; L~
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this.nStartPos = nStart; 1bwOmhkS  
this.nEndPos = nEnd; ysY*k`5  
nThreadID = id; j?4qO]_Wx+  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 5`p.#  
} uoh7Sz5!^  
]:J$w]\  
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public void run() AFwdJte9e  
{ uQKT  
while(nStartPos < nEndPos && !bStop) 63IM]J  
{ a9Zq
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]Zh%DQ  
try{ SOA,kwHRe  
URL url = new URL(sURL); 5\VWCI  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); c@L< Z`u  
httpConnection.setRequestProperty("User-Agent","NetFox"); U|R_OLWAg  
String sProperty = "bytes="+nStartPos+"-"; H0vfUF53l  
httpConnection.setRequestProperty("RANGE",sProperty); 8Z=R)asGS  
Utility.log(sProperty); |M;7>'YNC*  
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8zW2zkv2|#  
InputStream input = httpConnection.getInputStream(); =41?^1\  
//logResponseHead(httpConnection); <lJ345Q  
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byte[] b = new byte[1024]; (X*^dO  
int nRead; 1T n}
 
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ?(_08O  
{ QQc -Ya!v  
nStartPos += fileAccessI.write(b,0,nRead); 1EX;MW-p<T  
//if(nThreadID == 1) E}Uc7G  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); *MW\^PR?  
} >uEzw4w  
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="l/klYV  
Utility.log("Thread " + nThreadID + " is over!"); b^vQp
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bDownOver = true; )Hr`MB  
//nPos = fileAccessI.write (b,0,nRead); k)TpnH! "  
} XfIJ4ZM5  
catch(Exception e){e.printStackTrace ();} $U-0)4yf  
} =~LJ3sIX  
} Z*6IW7#  
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&m;*<}X  
//打印回应的头信息 Bdpy:'fJn  
public void logResponseHead(HttpURLConnection con) l,aay-E  
{ V0a3<6@4  
for(int i=1;;i++) w7&A0M  
{ k$:|-_(w  
String header=con.getHeaderFieldKey(i); C\hM =%  
if(header!=null) i SQu#p@  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); B&"Q\'c  
Utility.log(header+" : "+con.getHeaderField(header)); -MBxl`JU  
else [0("Q;Ec[j  
break; XW92gI<O  
} 9H1rO8k  
} +:/%3}
`  
:7;@ZEe  
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public void splitterStop() "_?nN"A7  
{ pEz_qy[#  
bStop = true; _+3::j~;m  
} 0JujesUw(  
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x}  
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} m+$VVn3Z}  

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/* V>3X\)qu  
**FileAccess.java XQw9~$  
*//文件访问(定位，写) )0k53-h&  
package NetFox; }c:M^Ff  
import java.io.*; G=bCNn<  
[()koU#w.  
uCB=u[]y4  
public class FileAccessI implements Serializable{ ;722\y(Y  
z\4.Gm-  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ;q>ah!"k  
RandomAccessFile oSavedFile; o^wqFX(Y  
long nPos; X2"/%!65{  
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{id4:^u&;  
public FileAccessI() throws IOException u)Whr@m  
{ %!#azI  
this("",0); ]hV*r@d  
} &BSn?  
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hgE71H\s  
public FileAccessI(String sName,long nPos) throws IOException w&.aQGR#  
{ Gav$HLx  
oSavedFile = new RandomAccessFile(sName,"rw"); h;'~,xA  
this.nPos = nPos; 0b 54fD=  
oSavedFile.seek(nPos); #T"4RrR  
} qZZK#,Qb  
)QJUUn#  
(**oRwr%  
public synchronized int write(byte[] b,int nStart,int nLen) ]eV8b*d6  
{ K:WDl;8(d  
int n = -1; 62NsJ<#>  
try{ b#o|6HkW  
oSavedFile.write(b,nStart,nLen); ]/{)bpu  
n = nLen; q1ma%
eiN  
} PZzMHK?hP  
catch(IOException e) f%8C!W]Dm  
{ "ocyK}l.?  
e.printStackTrace (); zKK9r~ M  
} b~cZS[S  
l%=;  
y<.5xq5_3  
return n; ez[Vm:2K  
} 4mbBmQV$#  
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} 8x
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/* EhBKj |y  
**SiteInfoBean.java Ws12b$  
*/ 5Yndc)Z  
package NetFox; [_:nHZb  
)YI(/*+]  
A?0Nm{O;3v  
public class SiteInfoBean { O33`+UV"W  
^kSqsT"  
0IWf!Sk ]  
private String sSiteURL; //Site's URL BL4-7  
private String sFilePath; //Saved File's Path A/?7w   
private String sFileName; //Saved File's Name Fs^Mw go  
private int nSplitter; //Count of Splited Downloading File MfkN]\Jyw  
kSo"Ak!  
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public SiteInfoBean() o,wUc"CE  
{//nSplitter的缺省值为5 ;9'OOz|+1  
//default value of nSplitter is 5 . 'yCw#f  
this("","","",5); $`'/+x"%  
} ^/k*h J{  
>5 BJ
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#,v{Ihn  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Z #m+ObHK1  
{ BLJj(-  
sSiteURL= sURL; wS3'?PRX  
sFilePath = sPath; a09<!0Rp  
sFileName = sName; 9Gz=lc[!7  
this.nSplitter = nSpiltter; >5SSQ\2~a  
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} 9o!Bzy+_  
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8a"%0d#  
public String getSSiteURL() xe$_aBU  
{ ,"0:3+(8;  
return sSiteURL; Q=dy<kg']  
} >`D:-huNeE  
7IM@i>p%  
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public void setSSiteURL(String value) {(?4!rh  
{ -35;j'a  
sSiteURL = value; SZCze"`[  
} K"@M,8hb  
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28u_!f[  
public String getSFilePath() h zn6kbv  
{ Ssg&QI  
return sFilePath; YZJyk:H\  
} 9-m=*|p  
Qe(
:|q_  
_h1mF<\ X^  
public void setSFilePath(String value) S
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{ _PR4`C*  
sFilePath = value; ={Qi0Pvt  
} MnW+25=N  
-`6+UkOV[x  
(&x['IR  
public String getSFileName() `~q<N  
{ Rbv;?'O$L  
return sFileName; o#1 $q`Z  
} /; 85i6  
IMONgFBS  
lU8Hd|@-  
public void setSFileName(String value) ENY+^7  
{ 3"\lu?-E  
sFileName = value; x'R`. !g3  
} o2\8OxcA  
x]ot 2  
<1M-Ro?5k  
public int getNSplitter() }*"p?L^p{  
{
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return nSplitter; ^K@C"j?M/  
} ;,e2egC'  
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public void setNSplitter(int nCount) ,s;UfF  
{ z2>lI9D4V  
nSplitter = nCount; Ooy7*W';  
} =odFmF  
} >[*qf9$  
(dSL7nel;L  
0{R=9wcc  
/* sD wqH.L  
**Utility.java 2jhxQL  
*/ Q]>.b%s[  
package NetFox; VP]%Hni]  
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public class Utility { !C:$?oU  
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public Utility() L;I]OC^J  
{ Q'0d~6n&{  
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} g}',(tPMZ  
'."ed%=MC  
//线程睡眠 @sC`!Rmy'-  
public static void sleep(int nSecond) oILZgNe'  
{ pIX`MlBdF  
try{ BF{Y"8u$  
Thread.sleep(nSecond); s-T\r"d=j  
} )I.$=s  
catch(Exception e) |# 2.Q:&  
{ Npy:!  
e.printStackTrace (); G<v&4/\p`M  
} WI-1)1t  
} ?<'}r7D   
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@_  
//日志 SI-Ops~e  
public static void log(String sMsg) 'SF<_aS(  
{ NHZz _a=  
System.err.println(sMsg); s,&Z=zt0R  
} JnM["Q=`  
'(|ofJe!  
_zi|  
public static void log(int sMsg) WEi2=3dV  
{ @2 fg~2M1  
System.err.println(sMsg); E09:E  
} iAIuxO  
} | h#u^v3  
W|63Ir67  
7E~;xn;  
/* fS78>*K  
**TestMethod.java Z}Ft:7   
*/ DN57p!z
 
package NetFox; o
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Z@PmM4F@S  
+!.^zp21  
public class TestMethod { F@B]et7  
?+}_1x`  
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public TestMethod() k_nql8H  
{ ///xx/weblogic60b2_win.exe ;@Y;g(bw:  
try{ e h?zNu2=  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ExL0?FemWV  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); -4{<=y?"a  
SiteFileFetch fileFetch = new SiteFileFetch(bean); lp%pbx43s  
fileFetch.start(); CN8Y\<Ar  
} H*'IK'O  
catch(Exception e){e.printStackTrace ();} JO6)-U$7UG  
KF!Yf\  
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} R)s:rJQ=p  
-**g~ty)  
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public static void main(String[] args) o9yJf#-En  
{ = x)-u8P  
new TestMethod(); '$]97b7G  
} O`t&ldU  
} y(yHt=r  
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