http断点续传简单实现（java)

/* pz^<\  
**SiteFileFetch.java VUU]Pu &  
*/ > Vb@[  
package NetFox; yWPIIWHx!  
import java.io.*; tEd.'D8 s  
import java.net.*; qgt[~i*  
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public class SiteFileFetch extends Thread { z~6y+  
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}`VDD?M  
SiteInfoBean siteInfoBean = null; //文件信息Bean R  
long[] nStartPos; //开始位置 N8cAqr  
long[] nEndPos; //结束位置 >>dm}X  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 9D\4n  
long nFileLength; //文件长度 AT Zhr. H  
boolean bFirst = true; //是否第一次取文件 ;|%dY{L-  
boolean bStop = false; //停止标志 n]W_e  
File tmpFile; //文件下载的临时信息 ewNz%_2  
DataOutputStream output; //输出到文件的输出流 \h
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） qr\!*\9  
public SiteFileFetch(SiteInfoBean bean) throws IOException oj,lz?  
{ '&O/g<Z}q  
siteInfoBean = bean; jd`},X/  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); O^>jdl!TZ  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); {Ee>n^1  
if(tmpFile.exists ()) _;A $C(  
{ [mxTa\  
bFirst = false; ExSe=4q#  
read_nPos(); /T^ JS  
} ylf[/='0K  
else !%<
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{ _?7#MWe&  
nStartPos = new long[bean.getNSplitter()]; /e\{   
nEndPos = new long[bean.getNSplitter()]; egR9AEJvz  
} <<9Va.  
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} +YOKA*  
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public void run() >4m'tZ8  
{ M x5`yT7  
//获得文件长度 Hs"(@eDV&J  
//分割文件 gMWBu~;!  
//实例FileSplitterFetch u/
b7Z`yX}  
//启动FileSplitterFetch线程 :H6FPV78  
//等待子线程返回 X C86-b)E  
try{ L(;WxHL  
if(bFirst) wmNHT _  
{ 3OyS8`  
nFileLength = getFileSize(); ~jU/<~s  
if(nFileLength == -1) 87!C@XlK_  
{ n>,L=wV  
System.err.println("File Length is not known!"); .Hhhi  
} foF19_2 ,  
else if(nFileLength == -2) {s?M*_{|  
{ )/ Ud^wi  
System.err.println("File is not access!"); ]e:/"  
} JE5  
else ;?fS(Vz~  
{ _Jz8{` "  
for(int i=0;i<nStartPos.length;i++) RT/o$$  
{ 4rK{-jvh>m  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); %z]U LEYrZ  
} h<<>
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for(int i=0;i<nEndPos.length-1;i++) u*S=[dq  
{ dhg~$CVO  
nEndPos = nStartPos[i+1]; gie
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} 6dH }]~a  
nEndPos[nEndPos.length-1] = nFileLength; z2gk[zY&  
} !2\ r LN  
} E"iUq  
Kr'f-{  
p=GWq(S6  
//启动子线程 t9 \x%=  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; DDT_kK;  
for(int i=0;i<nStartPos.length;i++) zIC;7 5#  
{ qL6c`(0  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), +i ?S  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), M$4k;  
nStartPos,nEndPos,i); ?PA$Ur21lw  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 1sE?YJP-  
fileSplitterFetch.start(); z't??6  
} CHd9l]Rbe  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), (YBMsh  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); T#%/s?_>.  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 5*PYT=p}  
nEndPos = " + nFileLength); #&<)! YY5  
// fileSplitterFetch[nPos.length-1].start(); N- e$^pST  
TlAR.cV  
;Mm7n12z C  
//等待子线程结束 ]$afC!Z  
//int count = 0; AT2v!mNyCw  
//是否结束while循环 G)#$]diNuX  
boolean breakWhile = false; !f>d_RG  
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while(!bStop) 7*j (*  
{ M)*\a/6?{  
write_nPos(); @uo ~nFj,  
Utility.sleep(500); tMj;s^P1  
breakWhile = true; 5tJ,7
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}nt* [:%  
for(int i=0;i<nStartPos.length;i++) |r ue=QZ  
{ z"D.Bm~]  
if(!fileSplitterFetch.bDownOver) 7\_o.(g#-  
{ I8oo~2Qw  
breakWhile = false; ly% F."v  
break; aKU*j9A?;Z  
} "~UUx"Y  
} 0CSv10Tg  
if(breakWhile) Z,B
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break; C]^H&  
/TS=7J#  
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//count++; ?!qY,9lhH  
//if(count>4) '`'GK&)  
// siteStop(); yA{W  
} B?VhIP e  
V"cKJ;s  
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System.err.println("文件下载结束！"); **69rN  
} tx?dIy;  
catch(Exception e){e.printStackTrace ();} v}WR+)uFQ  
} 6c0>gUQx-  
>#ZUfm{k$  
5SCKP<rb  
//获得文件长度 "~TA SX_?  
public long getFileSize() KfF!{g f  
{ 8* Jw0mSw  
int nFileLength = -1; %s19KGpA  
try{ Z{?G.L*/  
URL url = new URL(siteInfoBean.getSSiteURL()); q7u'_R,;  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); (8_\^jJ  
httpConnection.setRequestProperty("User-Agent","NetFox"); \.M*lqI  
1;<R#>&,*  
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int responseCode=httpConnection.getResponseCode(); hY`\&@  
if(responseCode>=400) OtFh,}E  
{ hy|b6wF&  
processErrorCode(responseCode); 9@+5LZR  
return -2; //-2 represent access is error z3?o|A}/W  
} HSq}7S&U  
vloF::1  
}@.|?2b +  
String sHeader; "Ks,kSEzu  
+SJd@y@fR  
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for(int i=1;;i++) Jmx Ko+-  
{ Sp@-p9#  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); +^;JS3p@\  
//Utility.log(in.readLine()); [$[:"N_  
sHeader=httpConnection.getHeaderFieldKey(i); k{t`|BnPKB  
if(sHeader!=null) ~i 7^P9  
{ >LDhU%bH  
if(sHeader.equals("Content-Length")) #c2ymQm  
{ Y`?-VaY  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); l&?ii68/  
break; r&FDEBh  
} $MJm*6h  
} e1P"[|9>R  
else sJNFFOz  
break; orb_"Qw  
} 5ZBKRu  
} $8BPlqBIZ  
catch(IOException e){e.printStackTrace ();} "Wx]RN:  
catch(Exception e){e.printStackTrace ();} =FD;~  
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Utility.log(nFileLength); 4
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return nFileLength; &\_iOw8  
} mkR2i>  
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/t(C>$ }p  
//保存下载信息（文件指针位置） }}<z/zN&^  
private void write_nPos() Rn@#d}  
{ Q$fmD  
try{ !^ _"~  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Q`D_|L  
output.writeInt(nStartPos.length); Od|$Y+@6  
for(int i=0;i<nStartPos.length;i++) "!EcbR  
{ HJY2#lSha6  
// output.writeLong(nPos); =Qn ;_+Ct  
output.writeLong(fileSplitterFetch.nStartPos); '}9JCJ  
output.writeLong(fileSplitterFetch.nEndPos); W|o'&
 
} #BSTlz  
output.close(); 'PP#^aI,  
} 0P]E6hWgg  
catch(IOException e){e.printStackTrace ();} h?pkE  
catch(Exception e){e.printStackTrace ();} FJd]D[h  
} FLY Ca  
c;'[W60  
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//读取保存的下载信息（文件指针位置） Hik3wPnp  
private void read_nPos() }C|dyyr  
{ *Aa?yg:=  
try{ wKsT7c'  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Cn[0(s6  
int nCount = input.readInt(); kTvd+TP4  
nStartPos = new long[nCount]; Kde9 $  
nEndPos = new long[nCount]; 2rZxSg  
for(int i=0;i<nStartPos.length;i++) /Js7`r=Rx  
{ fS`$'BQ  
nStartPos = input.readLong(); o-Ga3i 8  
nEndPos = input.readLong(); NhYLtw^u  
} Kx%Sku<F'  
input.close(); jNC4_q&  
} -bU oCF0  
catch(IOException e){e.printStackTrace ();} NW&b&o  
catch(Exception e){e.printStackTrace ();} {qa Aq%'  
} x UD-iSY  
)d>!"JB-  
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private void processErrorCode(int nErrorCode) +PuPO9jKO@  
{ }O4
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System.err.println("Error Code : " + nErrorCode); w4d--[Q  
} ]:~OG
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$ <#KA3o\  
//停止文件下载 X7g1:L1Ys  
public void siteStop() >:|q&|x-  
{ ;/rXQe1  
bStop = true; : 7`[$<~E  
for(int i=0;i<nStartPos.length;i++) +@/"%9w
 
fileSplitterFetch.splitterStop(); n .RhxgC<  
#
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} \<)9?M
:  
} AlIpsJ[UU  
//负责部分文件的抓取 o$Z6zmxO  
**FileSplitterFetch.java [YcG(^^  
*/ d|yAs5@  
package NetFox; '`uwJ&@  
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@>U-t{W  
import java.io.*; f|tjsZxQ  
import java.net.*; A?pbWt~
}  
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public class FileSplitterFetch extends Thread { 
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String sURL; //File URL j_
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long nStartPos; //File Snippet Start Position ] A+?EE2/  
long nEndPos; //File Snippet End Position T]=r Co  
int nThreadID; //Thread's ID {>)#H
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boolean bDownOver = false; //Downing is over }=]M2}  
boolean bStop = false; //Stop identical yLQ*"sw\  
FileAccessI fileAccessI = null; //File Access interface n@,G8=J?  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException FK5<6n,U  
{ n4#;k=mA  
this.sURL = sURL; pv Gf\pu  
this.nStartPos = nStart; b7p@Dn?E  
this.nEndPos = nEnd; {*I``T_+  
nThreadID = id; uW}s)j.  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 RpD=]y!5_  
} <yH4HY  
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io{@^1ab  
public void run() In<n&ib  
{ [c|]f_ZdK  
while(nStartPos < nEndPos && !bStop) ?1K#dC52#  
{ l)&X$3?tz  
jGpN,/VQa  
/*X2c6<d  
try{ O4V.11FnW  
URL url = new URL(sURL); 75/(??2  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); jT]0WS-b  
httpConnection.setRequestProperty("User-Agent","NetFox"); &N\jG373  
String sProperty = "bytes="+nStartPos+"-"; s)6U_  
httpConnection.setRequestProperty("RANGE",sProperty); ov_j4j>6P  
Utility.log(sProperty); z;|A(*Y  
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InputStream input = httpConnection.getInputStream(); #x 177I\  
//logResponseHead(httpConnection); q$B>|y U  
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byte[] b = new byte[1024]; \b?" b  
int nRead; &)AVzN+*h  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) IpcNuZo9&  
{ $+Z)  
nStartPos += fileAccessI.write(b,0,nRead); <~n"m  
//if(nThreadID == 1) pxCK;]  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); '+?"iVVo  
} OHb[qX\  
!`,Sfqij  
4'a=pnE$  
Utility.log("Thread " + nThreadID + " is over!"); ]<cK";  
bDownOver = true; odjT:Vr  
//nPos = fileAccessI.write (b,0,nRead); ujR_"r|l  
} w~"KA6^  
catch(Exception e){e.printStackTrace ();} ToXki,  
} $Bs {u=+w  
} kT"Kyd  
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//打印回应的头信息 \KQ71yqY  
public void logResponseHead(HttpURLConnection con) YkniiB[/  
{ 'E/^8md>  
for(int i=1;;i++) vdx0i&RiL  
{ $o0iLFIX/  
String header=con.getHeaderFieldKey(i); jv%kOovj  
if(header!=null) {=!b/l;@  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); &]v4@%<J  
Utility.log(header+" : "+con.getHeaderField(header)); \Zqng  
else HkUWehVm  
break; x7:s]<kE  
} )FF>IFHG  
} uW@oyZ

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public void splitterStop() aJ-K?xQ  
{ i|w81p^o  
bStop = true; h_:C+)13`x  
} q)S^P>  
*W0y: 3dB3  
vY }A  
} OWjk=u2Lz  
E:JJ3X|  
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/* )vjh~ybZ  
**FileAccess.java @SJL\{_  
*//文件访问(定位，写) ]iN'x?Fo  
package NetFox; \W1,F6&
j  
import java.io.*; R?~Yp?B^  
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public class FileAccessI implements Serializable{ P&9Gga^I  
-+ SF  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 <j*;.yyC  
RandomAccessFile oSavedFile; %{AO+u2i  
long nPos; !%^^\,  
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public FileAccessI() throws IOException J pFfzb  
{ M m[4yP%  
this("",0); Pz>s6 [ob  
} K`iv c N"  
#E?(vA1  
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public FileAccessI(String sName,long nPos) throws IOException @.b+av4J  
{ d F9!G;V  
oSavedFile = new RandomAccessFile(sName,"rw"); ,uo'c_f(e  
this.nPos = nPos; mef<=5t  
oSavedFile.seek(nPos); %\D)u8}  
} :=/85\P0SU  
<,Ue 0  
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public synchronized int write(byte[] b,int nStart,int nLen) xC*6vH]?  
{ lG4H:[5V  
int n = -1; l)Pu2!Ic  
try{ *AoR==:ya  
oSavedFile.write(b,nStart,nLen); QW$G  
n = nLen; 6|aKL[%6  
} ^* J2'X38I  
catch(IOException e) =U#dJ^4P  
{ $ et0s;GBv  
e.printStackTrace (); ]Y2RqXA*  
} *of3:w  
\R|4( +]x  
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return n; 7![,Q~Fy  
} lzYEx  
,_Z5m;  
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} ^aH\7J@Y  
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/* jDy-)2<  
**SiteInfoBean.java 4*Q#0`um  
*/ 99:C"`E{  
package NetFox; {DU`[:SQZg  
EQf[,  
x|mqL-Q f  
public class SiteInfoBean { J3n-`k8  
H*[M\gN$  
I_<I&{N>  
private String sSiteURL; //Site's URL x7~r,x(xM  
private String sFilePath; //Saved File's Path /lo2y?CS*  
private String sFileName; //Saved File's Name -amBB7g  
private int nSplitter; //Count of Splited Downloading File >sK!F$  
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K{[%7AM  
public SiteInfoBean() Zy o[(`y  
{//nSplitter的缺省值为5 R $&o*K`?  
//default value of nSplitter is 5 byTh/H  
this("","","",5); $e*ce94  
} G*-b}f
 
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) jg.QRny^  
{
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sSiteURL= sURL; c
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sFilePath = sPath; (+B5|_xQu  
sFileName = sName; <$X3Hye  
this.nSplitter = nSpiltter; a'2$
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} 8P1=[i]  
*T5!{  
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public String getSSiteURL() 1(|'W
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{ JwAYG5W  
return sSiteURL; ;i<|9
{;  
} eD*A)  
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;4.!H,d  
public void setSSiteURL(String value) l]8D7(g   
{
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sSiteURL = value; {=F/C,-  
} yF"1#{*y  
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OH">b6>\  
public String getSFilePath() Hm%;=`:'  
{ .6`9H 1  
return sFilePath; XpBj%e:  
} wid;8%m  
|j#C|V%kV  
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public void setSFilePath(String value) A?-oL='  
{ t.`@{R$hoA  
sFilePath = value; L$IQuy
 
} r[lF<2&*R  
<N_+=_  
@U3Vc|  
public String getSFileName() N6 (  
{ A-T]9f9  
return sFileName; Z|5?7v;h5  
} C4~;yhz  
:9$F'd\  
9Hc$G{[a  
public void setSFileName(String value) ev#;t@^
 
{ x)rM/Kq  
sFileName = value; \H=&`?  
} #m{UrTC  
;)!Sp:mHX  
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public int getNSplitter() .)<(Oj|4  
{ ~:3QBMk::  
return nSplitter; 'J6 M*vO  
} B:!W$<  
JWMpPzs  
b#K:_ac5
 
public void setNSplitter(int nCount) ],RdySN&  
{
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nSplitter = nCount; .h>8@5/s  
} WnGGo'
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} 6bBB/yd  
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J,AR5@)1  
/* Er+nk`UR_  
**Utility.java 2U; t(,dn'  
*/ |m80]@>  
package NetFox; H Ge0hl[n  
zJ)*Z,7  
=9"W@n[>W  
public class Utility { dO4
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Oh'Y0_oB>  
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public Utility() 
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{ DXa-rk8  
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^",ACWF4Sk  
} IjR'Qou5  
R8T]2?Q1  
//线程睡眠 .F(i/)vaq|  
public static void sleep(int nSecond) /l<<_uk$  
{ hYM@?/(q  
try{ ;Hj~
n+  
Thread.sleep(nSecond); * ;Cy=J+  
} ijdXU8  
catch(Exception e) /Ne<V2AX  
{ S}ECW,K  
e.printStackTrace (); !Z5[QNVaV  
} 8G5m{XTS(  
} >+ 4huRb  
,$ ^C4I  
//日志 vMs$ceq  
public static void log(String sMsg) `A,g] 1C:  
{ X0M1(BJgGo  
System.err.println(sMsg); ]<q[Do8k  
} KhW;RD  
NU*fg`w  
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public static void log(int sMsg) f}@jFhr'<  
{ S.d^T](  
System.err.println(sMsg); %bD}m!  
} =pznu+,  
} )"m!YuSY  
NSFs\a@1  
sqS=qC  
/* zBP>jM(8  
**TestMethod.java YNBHBK4;  
*/ n9\]S7]52  
package NetFox; ^+1#[E
  
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%O<%UmR  
public class TestMethod { >N?2""  
vQa'S-@u  
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public TestMethod() a+9*@z2  
{ ///xx/weblogic60b2_win.exe s9>(Jzcf9  
try{ 2AVa(  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); H-xFiF  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); yj$TPe_BW  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 1 `7<2w  
fileFetch.start(); ;_(PVo  
} wV)}a5+  
catch(Exception e){e.printStackTrace ();} j}AFE  
2EK
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2Gs$?}"a  
} ~6I)|^Z  
rJo"fx  
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public static void main(String[] args) _HA$ j2  
{ NKmoG\*  
new TestMethod(); :~ A%#  
} 5c;h&  
} !8@*F  
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