http断点续传简单实现（java)

/* 6vE#$(n#a&  
**SiteFileFetch.java (PGw{_  
*/ R2-F@_  
package NetFox; 3e1-w$z&S  
import java.io.*; Uuu2wz3O0  
import java.net.*; :Hm'o}  
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public class SiteFileFetch extends Thread { ZCc23UwI  
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SiteInfoBean siteInfoBean = null; //文件信息Bean j7gTVfO  
long[] nStartPos; //开始位置 >A-{/
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long[] nEndPos; //结束位置 un-%p#  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 H{=G\N{  
long nFileLength; //文件长度 d<Q%h?E  
boolean bFirst = true; //是否第一次取文件 ]3f[v:JQ  
boolean bStop = false; //停止标志 &;P\e  
File tmpFile; //文件下载的临时信息 u^{p'a'  
DataOutputStream output; //输出到文件的输出流 js <Up/1  
@
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） >Jx=k"Kv+  
public SiteFileFetch(SiteInfoBean bean) throws IOException =d^hiR!GN  
{ W&|?8%"l]  
siteInfoBean = bean; sRT H_]c  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Ti_G  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); \X%FM"r  
if(tmpFile.exists ()) ``VE<:2+  
{ i.)n#@M2  
bFirst = false; !<=zFy[J.9  
read_nPos(); n(eo_.W2|  
} 5!qf{4j  
else *p\Zc*N;%  
{ z`E=V  
nStartPos = new long[bean.getNSplitter()]; K2xHXziQ  
nEndPos = new long[bean.getNSplitter()]; : q%1Vi  
} tNzO1BK  
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* BR#^Wt  
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} Zf!Q4a"  
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public void run() g*YA~J@  
{ u$[8Zmgzz  
//获得文件长度 59l9_yFJ  
//分割文件 AmDOv4  
//实例FileSplitterFetch a<r,LE  
//启动FileSplitterFetch线程 X5J)1rL  
//等待子线程返回 ?i#x13  
try{ `j)56bR  
if(bFirst) @XzfuuE]  
{ JP6 Noia  
nFileLength = getFileSize(); A~a 3bCX+"  
if(nFileLength == -1) mKO~`Wq%@  
{ U.t][#<3  
System.err.println("File Length is not known!"); ]3Ia>i  
} !Ea!"}  
else if(nFileLength == -2) Q`Al
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{ 1#_pj eG  
System.err.println("File is not access!"); 2h51zG#qd  
} sa o&  
else h>GbJ/^  
{ :AztHf?X  
for(int i=0;i<nStartPos.length;i++) ~<VxtcEBz  
{ w$f_z*/  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); HSG Ln906  
} H6 x  
for(int i=0;i<nEndPos.length-1;i++) Y3:HQ0w`|  
{ W)Y`8&,  
nEndPos = nStartPos[i+1]; 6&SNFOX{@  
} zytN leyc  
nEndPos[nEndPos.length-1] = nFileLength; Q2m
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} m6BUKX\m  
} ~210O5^  
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9 CZ@IFS  
//启动子线程 _^GBfM.  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; h092S|iY  
for(int i=0;i<nStartPos.length;i++) |U{~t<BF#  
{ +CBN[/Z^i  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), d>)=|  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), c{y'&3\  
nStartPos,nEndPos,i); |f$+|9Q?  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); jH<Sf: Y(  
fileSplitterFetch.start(); SEzjc ~@3  
} dR\yRC]I  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), y<- ]'Yts  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); gtMR/P:S  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Fik;hB  
nEndPos = " + nFileLength); "0;WYw?  
// fileSplitterFetch[nPos.length-1].start(); A)
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,S`n?.&& 7  
//等待子线程结束 5O]tkHYR  
//int count = 0; p )JR5z  
//是否结束while循环 @Drl5C}+  
boolean breakWhile = false; SQK82/  
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!|4]V}JQ  
while(!bStop) _dk[k@5W{'  
{ Pa d)|  
write_nPos();
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Utility.sleep(500); Ij4q &i
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breakWhile = true; Posz|u<x  
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for(int i=0;i<nStartPos.length;i++) '1b8>L  
{ Bcv{Y\x;ko  
if(!fileSplitterFetch.bDownOver) RA<ky*^dr  
{ oA-,>:}g{  
breakWhile = false; v4|TQ8!wR  
break; m\jjj^f a  
} *> nOL  
} bskoi;)u  
if(breakWhile) p#P<V%  
break; Sq,>^|v4&e  
#b428-  
1ds4C:M+<  
//count++; ^\B4]'+^j  
//if(count>4) G9okl9;od  
// siteStop(); *Xk5H,:  
} |33t5}we  
a~LA&>@  
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System.err.println("文件下载结束！"); c8mh
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} OV;VsF  
catch(Exception e){e.printStackTrace ();} |VaJ70\o  
} 3^ UoK  
P/ 6$TgQ  
v?]a tb/h`  
//获得文件长度 ^TZmc{i  
public long getFileSize() hL/u5h%$  
{ -|}?+W  
int nFileLength = -1; 9rz$c, Y(  
try{ UJqh~s  
URL url = new URL(siteInfoBean.getSSiteURL()); IowXVdm@6  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 084Us s  
httpConnection.setRequestProperty("User-Agent","NetFox"); T<Xw[PEnP  
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o

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int responseCode=httpConnection.getResponseCode(); ].J;8}  
if(responseCode>=400) &D{!zF  
{ ZlC+DXg#S  
processErrorCode(responseCode); ?'f  
return -2; //-2 represent access is error b3>zdS]Q  
} cd1-2-4U  
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String sHeader; D%3$"4M7!  
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for(int i=1;;i++) Ua|iAD1  
{ :X}SuM?c  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); #lqH/>`>  
//Utility.log(in.readLine()); SN{A@dyt  
sHeader=httpConnection.getHeaderFieldKey(i); =C,DR4xh  
if(sHeader!=null) 0
^V<,CAV  
{ U{ 0~&  
if(sHeader.equals("Content-Length")) a"YVr'|  
{ &Cj~D$kDEu  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); P,m+^,  
break; _PPC?k{z!  
} j$_?g!I=gK  
} ^cPVnl  
else lbt8S.fx  
break; D1-w>Y#  
}
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} R2~y<^.V`Y  
catch(IOException e){e.printStackTrace ();} 5>%^"f  
catch(Exception e){e.printStackTrace ();} NX%1L! #  
6|q"lS*$S  
q j21#q .  
Utility.log(nFileLength); `.JW_F)1  
}a!|n4|`  
H?;+C/-K`_  
return nFileLength; dpS@:  
} x*F-d2D  
Mx,5  
/q>ExXsEC  
//保存下载信息（文件指针位置） bf.+Ewb(  
private void write_nPos() ,8Q0AkG  
{ QChWy`x  
try{ 9*FA=E  
output = new DataOutputStream(new FileOutputStream(tmpFile)); U}X'
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output.writeInt(nStartPos.length); JXkx!X_{  
for(int i=0;i<nStartPos.length;i++) vjGJRk|XED  
{ <Ez@cZ"  
// output.writeLong(nPos); 0$`pYW]  
output.writeLong(fileSplitterFetch.nStartPos); ku*k+4rz  
output.writeLong(fileSplitterFetch.nEndPos); qk'&:A  
} {ST8'hY  
output.close(); ZMMx)}hS  
} A3 TR'BFw-  
catch(IOException e){e.printStackTrace ();} 0B9FPpx?:  
catch(Exception e){e.printStackTrace ();} Ji,;ri2
i  
} nT=%3_.
 
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//读取保存的下载信息（文件指针位置） P]^8Enp
 
private void read_nPos() B0yGr\KJ  
{ 1t/c@YUTy  
try{ xzY/$?  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); C[znUI>  
int nCount = input.readInt(); sx+k V A  
nStartPos = new long[nCount]; '=+N )O  
nEndPos = new long[nCount]; :,p3&2I  
for(int i=0;i<nStartPos.length;i++) P]}:E+E<.I  
{ 11QZ- ^  
nStartPos = input.readLong(); j^
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nEndPos = input.readLong(); L T`T~|pz  
} 9HN&M*}  
input.close(); :tFcPc'  
} yO8@.-jb  
catch(IOException e){e.printStackTrace ();} e^\(bp+83  
catch(Exception e){e.printStackTrace ();} ]6v7iuvI  
} |wb_im  
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I&15[:b=-  
private void processErrorCode(int nErrorCode) ,ynN801\m  
{ lgVT~v{U`n  
System.err.println("Error Code : " + nErrorCode); T7ShE-X  
} In%FOPO  
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#+6j-^<_6  
//停止文件下载  7Tr '<(A  
public void siteStop() V+>RF  
{ Vo{ ~D:)  
bStop = true; jl7>  
for(int i=0;i<nStartPos.length;i++) 0[ "CP:u  
fileSplitterFetch.splitterStop(); hA/Es?U]  
F3!6}
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&-NGVPk81`  
} W=S^t_F  
} ^oC>,%7  
//负责部分文件的抓取 *dB3Gu{ +  
**FileSplitterFetch.java D?Ol)aj?  
*/ ?T%"Jgy8  
package NetFox; 0nI*9  
`3[
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import java.io.*; ~a7@O^q4  
import java.net.*; \hlS?uD\  
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 K\ pZ  
public class FileSplitterFetch extends Thread { A9Ea}v9:  
7w5l[a/  
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String sURL; //File URL ; 1?L  
long nStartPos; //File Snippet Start Position yP-$@Ry  
long nEndPos; //File Snippet End Position Gl{2"!mt=  
int nThreadID; //Thread's ID &u"mFweS  
boolean bDownOver = false; //Downing is over $@{d\@U  
boolean bStop = false; //Stop identical &?@U_emLi  
FileAccessI fileAccessI = null; //File Access interface Wkb>JnPo  
~9!@BL\  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException +('xzW  
{ e5FF'~A%]  
this.sURL = sURL; uW}M1kq?+l  
this.nStartPos = nStart; ):=8w.yC  
this.nEndPos = nEnd; fK@UlMC]7  
nThreadID = id; 2WKIO|'  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Ygfy;G%  
} rwwyYIlEg  
'R$/Qt;uA  
[UdJ(cGf  
public void run() t]3:vp5N]  
{ H,/=<Th;i  
while(nStartPos < nEndPos && !bStop) `7``1TL  
{ *6_>/!ywI  
%ID48_>*  
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try{ 's"aPqF?  
URL url = new URL(sURL); #cD$ DA  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); )cOBP}j+  
httpConnection.setRequestProperty("User-Agent","NetFox"); ]U4C2}u  
String sProperty = "bytes="+nStartPos+"-"; Ttb?x<)+8  
httpConnection.setRequestProperty("RANGE",sProperty); @1k-h;`,  
Utility.log(sProperty); tnb'\}Vn  
a(-t"OL\  
6]!Jo)BF  
InputStream input = httpConnection.getInputStream(); :W-xsw  
//logResponseHead(httpConnection); $RRh}w\0^  
- sq=|  
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byte[] b = new byte[1024]; h}m9L!+n8  
int nRead; |U~\;m@  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ?v+el,  
{ GIkVU6Q}  
nStartPos += fileAccessI.write(b,0,nRead); '|%\QWuZ  
//if(nThreadID == 1) u8x#XESR7  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); b
9Eb"  
} 70R_O&f-k  
\<}e?Yx%  
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>^  
Utility.log("Thread " + nThreadID + " is over!"); mX@xV*  
bDownOver = true; xf:|lQf  
//nPos = fileAccessI.write (b,0,nRead); tOQnxKzu  
} C2hB7?UGN  
catch(Exception e){e.printStackTrace ();} >IKIe  
} 6SAYe%e  
} zP!j {y4w  
7;#o?6!7  
PMj!T \B|  
//打印回应的头信息 $U^ Ms!'L  
public void logResponseHead(HttpURLConnection con) r/+~4W5  
{ );p:[=$71  
for(int i=1;;i++) @&Af[X4s  
{ a8y*Jz-E  
String header=con.getHeaderFieldKey(i); i Hcy,PBD  
if(header!=null) 5cr\ JR  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 6099w0fR`  
Utility.log(header+" : "+con.getHeaderField(header)); ; jJ%<  
else F'@[b   
break; }f6_7W%5  
} ~f8:sDJ  
}
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I<&)P#"  
y 5Kr<cF^  
public void splitterStop() =#I/x=
L:  
{ KW3
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bStop = true; ph7]*W-  
} )*BG-nM u  
^{O1+7d[.  
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} V$MMK  
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/* ML1/1GK*i+  
**FileAccess.java R8, g^N  
*//文件访问(定位，写) cEPqcy *  
package NetFox; Pfg.'Bl  
import java.io.*; n8)eC2A  
@PKY>58)  
[_tBv" z  
public class FileAccessI implements Serializable{ D'_w *  
7}fT7tsN  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 HAcC& s8  
RandomAccessFile oSavedFile; g % 8@pjk  
long nPos; MF5o\-&dN  
E^Z?X2Z  
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public FileAccessI() throws IOException 7Y1FFw|  
{ @_"Z]Y ,D0  
this("",0); Dgz^s^fxU  
} tNDv[I
F  
/V>yF&p  
`+T"^{ Z  
public FileAccessI(String sName,long nPos) throws IOException IKeO&]k  
{ f2M}N  
oSavedFile = new RandomAccessFile(sName,"rw");
6"c(5#H  
this.nPos = nPos; Zx%6pZ(.  
oSavedFile.seek(nPos); e:;u_be~  
} r)f+j@KF  
Wtj*Z.=:  
3c[TPD_:  
public synchronized int write(byte[] b,int nStart,int nLen) 3ZL<6`YF  
{ 8]% e[  
int n = -1; J@(69&  
try{ lD1m<AC  
oSavedFile.write(b,nStart,nLen); <L<d_  
n = nLen; 5wm(gF_t  
} 6tBe,'*  
catch(IOException e) u'"]{.K>fb  
{ {bO O?pp  
e.printStackTrace (); |Y;[)s =q  
} >B+!fi'SS>  
B5/
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j:'8yFi_  
return n; 43BqNQ0  
} D'\gy$9m1  
 s{T6qJ  
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} F+m;y  
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X32{y973hT  
/* %1kIaYZ  
**SiteInfoBean.java <2fgao&-n  
*/ 7NQEnAl  
package NetFox; LZ1)zoJ  
/n8\^4{fP{  
C\gKJW^]y@  
public class SiteInfoBean { ;^|:*  
/zIUYY  
OCbwV7q:  
private String sSiteURL; //Site's URL }6 MoC0  
private String sFilePath; //Saved File's Path DDp\*6y3l  
private String sFileName; //Saved File's Name t,308Z  
private int nSplitter; //Count of Splited Downloading File h=MEQ-3jg  
-~`)V`@  
18G=j@k7
  
public SiteInfoBean() RfzYoBN  
{//nSplitter的缺省值为5 e4Q2$Q@b  
//default value of nSplitter is 5 yuq2)  
this("","","",5); #,Cz+k*4  
} Mk!bmFZOZ  
QEc4l[^{.B  
sff4N>XAl<  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) J3_Ou2cF`  
{ L4or*C^3  
sSiteURL= sURL; 1SSS0&  
sFilePath = sPath; 80 ckh  
sFileName = sName; OzAxnd\.N  
this.nSplitter = nSpiltter; A/88WC$v  
g,s^qW0vds  
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} ZMO ym=  
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.pyNET  
public String getSSiteURL() sI6coe5n  
{ y1 a1UiHGP  
return sSiteURL; 
r>B|JPm  
} :?SD#Vvrh.  
!TLJk]7uC  
)F,z pGG  
public void setSSiteURL(String value) %`}nP3  
{ @IV,sze  
sSiteURL = value; qpV"ii  
} /n1L},67h  
Q+ZZwqyxD  
hd@jm^k  
public String getSFilePath() 3>mAZZL5[  
{ j?1wP6/NP  
return sFilePath; 1x^Vv;K  
} QAX3*%h  
heQ
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PP8627uP  
public void setSFilePath(String value) %F13*hOu  
{ 8T8
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sFilePath = value; /cZTj!M  
} }/MmuPp  
lE
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^o4](l  
public String getSFileName() &1ZUMc  
{ oqbhb1D1<  
return sFileName; >35W{d  
} H`1q8}m  
=:'\wx X  
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public void setSFileName(String value) st)qw]Dn;Y  
{ i@mS8%|l  
sFileName = value; i(> WeC+  
} 3!vnSX(iv  

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z! :0%qu  
public int getNSplitter() WV}HN  
{ IYv.~IQO  
return nSplitter; CV)K=Br5&_  
} a9NIK/9  
"EwzuM8f  
8J:=@X^}  
public void setNSplitter(int nCount) 6B+?X5-6DH  
{ nWA>u J5  
nSplitter = nCount; w@pJ49  
}
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} ]A%~bQ7  
\}W !  
>R5A@0@d5  
/* `\GRY @cg  
**Utility.java \,'4eV  
*/ w)&?9?~  
package NetFox; 3^5h:OaT  
6-FM<@H{  
aJ}hlM>  
public class Utility { oU se~  
)!~,xl^j{}  
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public Utility() WyRSy-{U(}  
{ FC WF$'cO  
F)4I70vG  
n|Ts:>`V  
} 'KDt%?24  
3aU5rbi|B  
//线程睡眠 t~<HFY*w  
public static void sleep(int nSecond) ) ]DqK<-  
{ 0s79rJ  
try{ &2S-scP  
Thread.sleep(nSecond); k(o(:-+x  
} Rh#`AM`)j  
catch(Exception e) S|af?IW  
{ ;hF}"shJN  
e.printStackTrace (); z[6avW"q  
} ,4Q8r:_ u  
} 2|ej~}Y  
U({
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//日志 X}Om)WCr  
public static void log(String sMsg) n.t5:SW  
{ ;M~9Yr=1  
System.err.println(sMsg); Y>atJ  
} <@[;IX`YN  
6lT< lzT  
6TTu[*0NT  
public static void log(int sMsg) aRElk&M  
{ 8!YQ9T[  
System.err.println(sMsg); 'n=bQ"bQu  
} yEk|(6+^  
} }ice*3'3  
B!&y>Z^$  
K1o>>388G  
/* r+h%a~A#>  
**TestMethod.java Xu E' %;:  
*/ !&:
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package NetFox; ?8/r=  
zliMG=6  
/q}(KJX  
public class TestMethod { _>BYUPY  
HDTA`h?t;  
hnH<m7  
public TestMethod() }a#T\6rY  
{ ///xx/weblogic60b2_win.exe ||fw!8E  
try{ yYSmmgrX0  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Ghc U~  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); %?, 7!|Ls  
SiteFileFetch fileFetch = new SiteFileFetch(bean); !#~KSO}zW2  
fileFetch.start(); m.!LL]]  
} bI|{TKKN&P  
catch(Exception e){e.printStackTrace ();} TGU7o:2  
J9OL>!J  
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} d
3 i(UN]  
:y`LF<  
\F-n}Z  
public static void main(String[] args) ,|A6l?iV  
{ ?@Q0;LG  
new TestMethod(); <T;V9(66  
} *C0a,G4  
} ,A $IFE  
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