http断点续传简单实现（java)

/* "b;k.Fx  
**SiteFileFetch.java KqY>4tb  
*/ s.ey!ew  
package NetFox; ^ N_`^m  
import java.io.*; ZArf;&8  
import java.net.*; n(# c`t*  
@f'AWeJ2  
?(M\:`G'  
public class SiteFileFetch extends Thread { lMPbLF%_  
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SiteInfoBean siteInfoBean = null; //文件信息Bean h!;MBn`8  
long[] nStartPos; //开始位置 ceI [hM  
long[] nEndPos; //结束位置 &:,fb]p  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 4w2L?PDMi  
long nFileLength; //文件长度 Ae3#>[]{  
boolean bFirst = true; //是否第一次取文件 9&[\*{  
boolean bStop = false; //停止标志 3~8AcX@  
File tmpFile; //文件下载的临时信息 ri;r7Y9V9`  
DataOutputStream output; //输出到文件的输出流 '4Y*-!9  
@) ]t8(  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ~l@%=/m  
public SiteFileFetch(SiteInfoBean bean) throws IOException a\|X^%2g  
{ B)(w%\M4^  
siteInfoBean = bean; "URVX1#(r  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); kfIbgya  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); &A#90xzF  
if(tmpFile.exists ()) D`5: JR-{  
{ ]n/jJ_[  
bFirst = false; m';|}z'  
read_nPos(); JCBnFrP  
}  K oL%}u&  
else 0c{Gr 0[>  
{ p@`4 Qz  
nStartPos = new long[bean.getNSplitter()]; %hrsE5k^,  
nEndPos = new long[bean.getNSplitter()]; RH1U_gp4 ]  
} KN|'|2/|  
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} )z|_*||WU^  
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.|tQ=l@I  
public void run() iNMLYYq]l  
{ o<Ke3?J\  
//获得文件长度 8~rT  
//分割文件 .jy)>"h0  
//实例FileSplitterFetch P/HHWiD`D  
//启动FileSplitterFetch线程 y0lLFe~  
//等待子线程返回 SlM>";C\  
try{ aj+zmk~-  
if(bFirst) I%C]>ZZh  
{ _LLW{^V  
nFileLength = getFileSize(); N>h]mX6  
if(nFileLength == -1) 1j8/4:  
{ VN1#8{  
System.err.println("File Length is not known!"); LH1BZ(5g  
} +X{cN5Y K  
else if(nFileLength == -2) d;IJ0xB+by  
{ F12S(5Z0%  
System.err.println("File is not access!"); yRSy(/L^+  
} oKZ[0(4<  
else WIhIEU7/  
{ UEk|8yq  
for(int i=0;i<nStartPos.length;i++) 7UY('Q[  
{ ^!XU+e+:0  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); HE4`9$kVLr  
} w`2_6[,9  
for(int i=0;i<nEndPos.length-1;i++) g5?r9e  
{ ~r7DEy|+  
nEndPos = nStartPos[i+1]; "`H=AX0  
} )2   
nEndPos[nEndPos.length-1] = nFileLength; Sf#\6X<B  
} |8b$x|
B  
} |Sy}d[VKsZ  
+<vqkc  
)@?Qt2  
//启动子线程 fLf#2EA  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; jauc*347  
for(int i=0;i<nStartPos.length;i++) &^"s=g.  
{ +A;n*DF2  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), +;{rU&  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ,=x.aX Spz  
nStartPos,nEndPos,i); ixoMccU0  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); zSX'  
fileSplitterFetch.start(); S+4I[|T]Y  
} Ta!m%=8  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), }j]<&I}  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); $NH`Iu9t  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ~QQEHx\4zZ  
nEndPos = " + nFileLength); 50O7=  
// fileSplitterFetch[nPos.length-1].start(); ([z<TS#Md  
4'7 v!I9  
#w[q.+A  
//等待子线程结束 7cJO)cm0'  
//int count = 0; 2\kC_o97  
//是否结束while循环 bs4fyb  
boolean breakWhile = false; W,L>'$#pM  
l[ZQ7$kL  
!IQ
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while(!bStop)
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{ 'npT+p$V  
write_nPos(); F5om-tzy  
Utility.sleep(500); 6jQ&dN{=qB  
breakWhile = true; ;+#za?w  
M,=@
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{g23[$X]N  
for(int i=0;i<nStartPos.length;i++) I{Y {
  
{ xP|%rl4  
if(!fileSplitterFetch.bDownOver) c+YYM :S  
{ Xv<;[vq}F  
breakWhile = false; v{\n^|=])  
break; Es ZnGuY  
} iLI.e rm  
} I=3B 5u  
if(breakWhile) ".Q!8j"@f  
break; 96([V|5K  
7J</7\  
?3KR(6D  
//count++; %$!R]B)  
//if(count>4) 9Le/'ovq  
// siteStop(); n8
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} R-0_226  
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System.err.println("文件下载结束！"); !Barc,kA  
} C$]%1<-Iv]  
catch(Exception e){e.printStackTrace ();} W6!4Qyn  
} U- UV<}  
2rE~V.)%  
&d &oP  
//获得文件长度 {O3oUE+  
public long getFileSize() yScov)dp(  
{ F"HI>t)>  
int nFileLength = -1; 0'`8HP  
try{ iMY0xf8l  
URL url = new URL(siteInfoBean.getSSiteURL()); '"G %0y  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); +h9l%Pz  
httpConnection.setRequestProperty("User-Agent","NetFox"); +X|m>9  
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int responseCode=httpConnection.getResponseCode(); p.W*j^';Q  
if(responseCode>=400) \p=W4W/  
{ `!>dbR&1  
processErrorCode(responseCode); Jr*S2z<*  
return -2; //-2 represent access is error U
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} Z2pN<S{5  
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Rs(CrB/M  
String sHeader; H--*[3".  
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for(int i=1;;i++) Eg-Mm4o  
{ 6pdl,5[x-  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Lb3K};SIV  
//Utility.log(in.readLine()); +8@`lDnr  
sHeader=httpConnection.getHeaderFieldKey(i); +e3WwU
x  
if(sHeader!=null)
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{ *Yk8Mj^_h  
if(sHeader.equals("Content-Length")) e7)%=F/)  
{ (8eNZ*+mO  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); N@du.d:  
break; 1p"EE~v  
} XCi]()TZ_  
} j*Wh;I+h  
else q MT.7n:  
break; -GkK[KCH  
} E+m"yQp{  
} RNrYT|  
catch(IOException e){e.printStackTrace ();} ek.WuOs  
catch(Exception e){e.printStackTrace ();} _)Z7Le:f!  
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;h(;(  
Utility.log(nFileLength); .0*CT:1=0  
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return nFileLength; :,z3:PL  
} D``NQ`>A  
*e"GQd?  
_2Xu1q.6~5  
//保存下载信息（文件指针位置） _=^hnv  
private void write_nPos() U"Ob@$ROFy  
{ R_*D7|v  
try{ j?KB8oY`TP  
output = new DataOutputStream(new FileOutputStream(tmpFile));
$?JLCa  
output.writeInt(nStartPos.length); ]ieA?:0Hi  
for(int i=0;i<nStartPos.length;i++) -$MC  
{ (l!D=qy  
// output.writeLong(nPos); sq(063l  
output.writeLong(fileSplitterFetch.nStartPos); en#g<on  
output.writeLong(fileSplitterFetch.nEndPos); )PoI~km  
} U.j\u>a  
output.close(); S%gO6&
^  
} SlJ/OcAf#  
catch(IOException e){e.printStackTrace ();} j6d"8oH _  
catch(Exception e){e.printStackTrace ();} T_9ZI|Jx  
} 4l!Yop0h  
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WQmiG=Dw^  
//读取保存的下载信息（文件指针位置） ~Z/`W`  
private void read_nPos() ~JRuMP  
{ 8sjHQ)<  
try{ 6l]?%0[*  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ~aR='\<  
int nCount = input.readInt(); ysT!^-&p  
nStartPos = new long[nCount]; c:_i)":  
nEndPos = new long[nCount]; a.U:B [v`  
for(int i=0;i<nStartPos.length;i++) Gv nclnG  
{ V7'x? pt  
nStartPos = input.readLong(); ?9okjLp1n  
nEndPos = input.readLong(); D}/.;]w<[&  
} gx9sBkoq5D  
input.close(); KA{DN!  
} GvtI-\h]  
catch(IOException e){e.printStackTrace ();} V5@[7ncVf  
catch(Exception e){e.printStackTrace ();} <l s/3!  
} >W]"a3E  
-:p1gg&  
nu%Nt"~[%  
private void processErrorCode(int nErrorCode) Dt'e<d Is  
{ CZ%"Pqy&1L  
System.err.println("Error Code : " + nErrorCode); SR8Kzk{  
} #2'&=?J1r  
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)n[Mh!mn  
//停止文件下载 <mgTWv  
public void siteStop() WuZn|j'  
{ iZUz6  
bStop = true; \bl,_{z?  
for(int i=0;i<nStartPos.length;i++) *rKv`nva5  
fileSplitterFetch.splitterStop(); <21^{ yt1  
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} R
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} 0Lz56e'j  
//负责部分文件的抓取 AS"|r  
**FileSplitterFetch.java tYNt>9L|  
*/ Wq&c,H  
package NetFox; !4.^@^L|\  
"8dnFrE  
(s*Uz3sq  
import java.io.*; 1% %Tm"  
import java.net.*; @!NHeH=pR  
e[&3K<  
MW@b;=(  
public class FileSplitterFetch extends Thread { $,#IPoi~X  
lc(iy:
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String sURL; //File URL H0NyxG<  
long nStartPos; //File Snippet Start Position ZoReyY2  
long nEndPos; //File Snippet End Position R:m=HS_  
int nThreadID; //Thread's ID QD VA*6F  
boolean bDownOver = false; //Downing is over D)cwttH  
boolean bStop = false; //Stop identical ZGvNEjff  
FileAccessI fileAccessI = null; //File Access interface #@"rp]1xv  
>ZsK5v  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException S2SQ;s-t_  
{ Z'bMIdV  
this.sURL = sURL; {v/6|  
this.nStartPos = nStart; <rmV$_  
this.nEndPos = nEnd; @<JQn^M  
nThreadID = id; 4DM|OL`w  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ]-LE'Px|  
} 5)i0g  
?S:_J!vX{  
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public void run() +%$V?y (  
{ kakWXGeR  
while(nStartPos < nEndPos && !bStop) $gK>R5^G>  
{ ${eh52)`  
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6{WT;W>WT:  
try{ 640V&<+v  
URL url = new URL(sURL); TBYL~QQD\C  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); L(S.  
httpConnection.setRequestProperty("User-Agent","NetFox"); Z}StA0F_  
String sProperty = "bytes="+nStartPos+"-"; F
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httpConnection.setRequestProperty("RANGE",sProperty); p}X87Zq  
Utility.log(sProperty); - $/{V&?t  
,Gx=e!-N5  
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InputStream input = httpConnection.getInputStream(); 3iL&;D  
//logResponseHead(httpConnection); iiB$<b.((I  
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byte[] b = new byte[1024]; M)Q+_c2*  
int nRead; 
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while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) @eU/g![u  
{ UbH=W(%  
nStartPos += fileAccessI.write(b,0,nRead); $ayD55W4  
//if(nThreadID == 1) P*sCrGO%  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Sd11ZC6  
} e 3oIoj4o  
IvH+94[)  
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Utility.log("Thread " + nThreadID + " is over!"); El}z^e  
bDownOver = true; _%!hk
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//nPos = fileAccessI.write (b,0,nRead); F\<i>LWT'  
} Sp:de,9@  
catch(Exception e){e.printStackTrace ();} .?:~s8kB  
} _zwuK
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} M/;g|J jM  
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6nhB1Aei  
//打印回应的头信息 8;rS"!
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public void logResponseHead(HttpURLConnection con) {4*%\?c,n  
{ \zyGJyy.  
for(int i=1;;i++) xbA2R4|  
{ n_glYSV!  
String header=con.getHeaderFieldKey(i); &t4(86Bmq  
if(header!=null) Vd~k4  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); +N:%`9}2V  
Utility.log(header+" : "+con.getHeaderField(header)); Zv7)+Q  
else h 42?^mV4?  
break; ;Yj&7k1  
} <0}'#9>O  
} z0Hh8*  
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aR $P}]H  
public void splitterStop() +M:Q!'  
{ |05LH
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bStop = true; @DR&e^Zz  
} 9hU@VPB~  
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)cXc"aj@s  
} z>~3*a9&  
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/* Gx)D~7lz  
**FileAccess.java P]GGnT
(!  
*//文件访问(定位，写) ]f?LQCTq<b  
package NetFox; 0g\&3EvD  
import java.io.*;
.EQFHStr  
ln7.>.F  

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public class FileAccessI implements Serializable{ 0kfw8Lon  
[U0c
 
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 9mZ1 a6,x  
RandomAccessFile oSavedFile; 0Jr<>7Q1  
long nPos; nceF4Ty  
^xrR3m*d  
&-A7%"  
public FileAccessI() throws IOException 1;V5b+b  
{ g&V.o5jIhc  
this("",0); Xqk$[peS  
} oGZ9@Y)(T  
~MX@-Ff  
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public FileAccessI(String sName,long nPos) throws IOException 3ssio-X  
{ p"Y=  
oSavedFile = new RandomAccessFile(sName,"rw"); H Vy^^$  
this.nPos = nPos; 0a5P@;"a  
oSavedFile.seek(nPos); '`u1,h  
} kcb'`<B  
\N)FUYoHg  
=k z;CS+  
public synchronized int write(byte[] b,int nStart,int nLen) ?}.(k/  
{ {U9jA
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int n = -1; (Lp-3Xx  
try{ Gex^\gf  
oSavedFile.write(b,nStart,nLen); %oo&
M;  
n = nLen; =zKp(_[D  
} x$E l7=.  
catch(IOException e) pFuQ!7Uk  
{ $O#h4
L_  
e.printStackTrace (); kH'Cx^=c6h  
} '%,Re-8O  
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return n; ='FEC-f95  
} <~3 aaO  
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} h;6@-\6  
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:Z)s'd.  
/* T-\
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**SiteInfoBean.java gM8eO-d  
*/ c8u0\X,  
package NetFox; >,v~,<3 i  
*VUXw@  
<KpQu%2(  
public class SiteInfoBean { y.Py>GJJ1S  
_:z~P<%s  
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private String sSiteURL; //Site's URL ) E\pQ5&  
private String sFilePath; //Saved File's Path VXa]L4jJ9  
private String sFileName; //Saved File's Name 1#V0g Q  
private int nSplitter; //Count of Splited Downloading File B
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public SiteInfoBean() $2.DZ  
{//nSplitter的缺省值为5 3Rm$  
//default value of nSplitter is 5 AYi$LsLhO  
this("","","",5); hug12Cu  
} ,ZSuo4  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) >dM
'
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{ Wwz>tE  
sSiteURL= sURL; ps]6,@uyB  
sFilePath = sPath; xqr`T0!&  
sFileName = sName; UaBR;v-.B3  
this.nSplitter = nSpiltter; kBTuM"  
b7
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`XnFc*L 1  
} Bw$-*FYE  
ns3k{l#  
oTL "]3`'  
public String getSSiteURL() ,uw&)A  
{ kahv1s-  
return sSiteURL; ?z6C8T~+  
} L=$P  
fkYQ3d,`  
OV[-m;h|  
public void setSSiteURL(String value) Zwcb5\Q  
{ ovl@[>OB  
sSiteURL = value; yP-Dj ,  
} I}:/v$btM  
*n47.(a2i  
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public String getSFilePath() 'fB`e]_  
{ dcA0k  
return sFilePath; IoX(Pa  
} ql4T@r3l}3  
c*h5lM'n6  
,kP{3.#Q  
public void setSFilePath(String value) _w26
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{ _k}b  
sFilePath = value; ("aYjKk  
} * n[6H  
=:b/z1-v  
#: F)A_Y  
public String getSFileName() 3lJK[V{'#'  
{ A;g[G>J  
return sFileName; pSAXp#g  
} >8VJ!Kg4  
Ua:EI!`  
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public void setSFileName(String value)  LKm5U6  
{ BP7_o63/G  
sFileName = value;  A=,
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} YP6+o#==  
)KNFS,5  
#qPk,a  
public int getNSplitter() .B)v "Sw#  
{ ":Q70*xSm  
return nSplitter; us]ah~U6A  
} xj}N;FWo  
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public void setNSplitter(int nCount) V}(%2W5X+  
{ K+7xjFoDIR  
nSplitter = nCount; [;2v[&
Po  
} u66w('2  
} Cr&ua|%F  
&8(2U-  
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/* G6 GXC`^+  
**Utility.java c" l~=1Dr  
*/ rUyT5Vf  
package NetFox; )yK!EK\  
#*~ (  
d ][E;$  
public class Utility { IL~yJx_11  
iD\joh-C  
+EFurdX\  
public Utility() J@$>d  
{ uIR_p\)  
X@cV']#V  
"ZH1W9A  
} =gj]R  
)FB)ZK;  
//线程睡眠 4Qw!YI#40$  
public static void sleep(int nSecond) :!|xg!|y  
{ (R0  
try{ H'P
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Thread.sleep(nSecond); c"|^Lo.  
} cO<x:{`  
catch(Exception e) 7#RW4ZM  
{ Ghj6&K%b0  
e.printStackTrace (); ,
^'
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} KLxg  
} v\<`"  
:s4CWEd  
//日志 A*$vk
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public static void log(String sMsg) wM|-u/9+  
{ %~eZrG.  
System.err.println(sMsg); CocvEoE*z  
} E1>3[3  
~r{Nc j  
gh~C.>W}q+  
public static void log(int sMsg) R&-bA3w$  
{ s0\X%U("  
System.err.println(sMsg); R)H@'X  
} ~"LOw_BRh  
} dx~F [  
:gR
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<}e<Zf!  
/* 1mB6rp  
**TestMethod.java U$-FQRM4K  
*/ jW6@U%[!b  
package NetFox; wOOPuCw?  
kt@+UK."  
:>cJ[K?0  
public class TestMethod { x|Q6[Y  
F:\y#U6"J  
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public TestMethod() JY /Cd6\  
{ ///xx/weblogic60b2_win.exe KsHMAp3  
try{ F6fm{  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ;A|6&~E0G  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 8`im4.~#%  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 1sgoT f%  
fileFetch.start(); fc M~4yP?  
} #$8tBo  
catch(Exception e){e.printStackTrace ();} `a<G7  
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} h5Z%|J>;
0  
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public static void main(String[] args) 4YdmG.CU  
{ {6~W2zX&  
new TestMethod(); 6-<r@{m$  
} n0EKNMO  
} Ble <n6  
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