http断点续传简单实现（java)

/* oChf&W 8u  
**SiteFileFetch.java q#8z%/~k  
*/ !:_krLB<  
package NetFox; !l9#a{#6l  
import java.io.*; 6Tq2WZ}<'  
import java.net.*; Pi%-bD/w  
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public class SiteFileFetch extends Thread { l`:-B'WM  
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SiteInfoBean siteInfoBean = null; //文件信息Bean COH.`Tv{*  
long[] nStartPos; //开始位置 #S|On[Q!  
long[] nEndPos; //结束位置 [eDRghK  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 g)<
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long nFileLength; //文件长度 /pGx!  
boolean bFirst = true; //是否第一次取文件 i-sm9K'ns  
boolean bStop = false; //停止标志 TP`"x}ACa?  
File tmpFile; //文件下载的临时信息 K$$%j"s
 
DataOutputStream output; //输出到文件的输出流 j{m{hVa  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） /sSif0I24  
public SiteFileFetch(SiteInfoBean bean) throws IOException tU8aPiUl  
{ e.|t12)L "  
siteInfoBean = bean; :yOJL [x  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Hjy4tA7,l  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); xfqu=z8X  
if(tmpFile.exists ()) ,`$2  
{ 2\Yv;J+;  
bFirst = false; |fn%!d`2  
read_nPos(); U71A#OD^U  
} RS7J~Q  
else Vl:M6d1  
{ A<[w'"  
nStartPos = new long[bean.getNSplitter()]; <.@w%rvG  
nEndPos = new long[bean.getNSplitter()]; Sh<A936/E  
} (B].ppBii  
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} ;|CG9|p
 
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public void run() oIKuo~  
{ kChCo0Q>
1  
//获得文件长度 uD`Z\@Z  
//分割文件 =?hbi]  
//实例FileSplitterFetch .R@euIva
 
//启动FileSplitterFetch线程 
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//等待子线程返回 EmV ZqW  
try{ 9lX+?m~ ~  
if(bFirst) >>>MTV f  
{ ,0n=*o@W  
nFileLength = getFileSize(); sDy~<$l?  
if(nFileLength == -1) cdfnM%`>\  
{ SsIN@  
System.err.println("File Length is not known!"); zOL*XZ0c  
} 8w3Wy<}y  
else if(nFileLength == -2) T(*A0  
{ uq]E^#^  
System.err.println("File is not access!"); 5=.mg6:  
} @N\ Ht'f  
else H4e2#]*i7  
{ 42 rIIJ1A  
for(int i=0;i<nStartPos.length;i++) uU8L93  
{ l{3ZN"`I  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); jTok1k  
} l @r`NFWD@  
for(int i=0;i<nEndPos.length-1;i++) N*Xl0m(Q  
{ A)f/ww)Q  
nEndPos = nStartPos[i+1]; 1h?:gOig  
} tkhEjTZ  
nEndPos[nEndPos.length-1] = nFileLength; -k3WY&9,  
} &_Gu'A({J  
}  #U/L8  
|Lz7}g=6  
.@f)#2  
//启动子线程 |Fzt| \  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length];
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for(int i=0;i<nStartPos.length;i++) $K!6T  
{ rK cr1VFy  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), zm^5WH  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), z%/<|` 7  
nStartPos,nEndPos,i); Dl=vv9
 
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); yc@:*Z  
fileSplitterFetch.start(); bKPjxN?!9  
} #r80FVwiD  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), rj;~SC{  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); `
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// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ?Q}3X-xy  
nEndPos = " + nFileLength); M_F4I$V4  
// fileSplitterFetch[nPos.length-1].start(); DOWZhD  
T;B/Wm!x  
:J6FI6  
//等待子线程结束 l65Qk2<YC  
//int count = 0; t?_{  
//是否结束while循环 `qr.@0whP  
boolean breakWhile = false; lJBZ0  
:j% B(@b  
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while(!bStop) yI$MqR  
{ unkA%x{W;  
write_nPos(); X0%BE!  
Utility.sleep(500); qnU$Pd  
breakWhile = true; vXc
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1?#Wg>7'  
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for(int i=0;i<nStartPos.length;i++) qk\LfRbj  
{ Z+! 96LR  
if(!fileSplitterFetch.bDownOver) -<gQ>`(0  
{ _1HEGX\  
breakWhile = false; !o/;"'&E  
break; Yk#$-"c/a  
} ' ui`EL%  
} &ETPYf%#  
if(breakWhile) v1Jg8L=  
break; SCD;(I~4  
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6
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//count++; 5lakP?  
//if(count>4) ;F>I+l_X  
// siteStop(); Y]HtO^T2  
} )N]%cO(^  
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[r=U-  
System.err.println("文件下载结束！"); *uZ'MS  
} lyrwm{&  
catch(Exception e){e.printStackTrace ();} M%FKg/  
} m}fY5r<<;/  
t)*A#
  
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//获得文件长度 0'tm.,  
public long getFileSize() Dlu]4n[LB  
{ /pnQKy.  
int nFileLength = -1; C)qP9uW  
try{ ,DWC=:@X  
URL url = new URL(siteInfoBean.getSSiteURL()); |:d:uj/  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); mi{ r7.e5I  
httpConnection.setRequestProperty("User-Agent","NetFox"); jh.e&6  
1"HSM=p  
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int responseCode=httpConnection.getResponseCode(); 7)v`l1  
if(responseCode>=400) q e;O Ox  
{ N`i`[ f  
processErrorCode(responseCode); %c,CfhEV%&  
return -2; //-2 represent access is error STQ~mFs"  
} {_*$X  
ffE>%M*  
JQWW's}  
String sHeader; =)y=39&;/  
lIL{*q(  
jp QmKX  
for(int i=1;;i++) Kkz2N  
{ AZjj71UE  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); I~I$/j]e`  
//Utility.log(in.readLine()); &T/}
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sHeader=httpConnection.getHeaderFieldKey(i); vH9Gf  
if(sHeader!=null) 'l3K*lck  
{ {V9}W<  
if(sHeader.equals("Content-Length")) (Qys`D   
{ }X*.Vv A  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ) "Toh=x]  
break; /2PsC*y  
} k34!*(`q
  
} qfzT8-Y  
else ;Cqjg.wkB  
break; N?;5%pG <  
} B[Fuyy?  
} rSfvHO:R  
catch(IOException e){e.printStackTrace ();} O1K~]Nt  
catch(Exception e){e.printStackTrace ();} )Y+?)=~  
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,\
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Utility.log(nFileLength); E8.xmTq  
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return nFileLength; M.R]hI  
} VpMPTEZ*L  
b/Z0{38  
Z'sO9Sg8>  
//保存下载信息（文件指针位置） ?*8HZ1m#  
private void write_nPos() 5Pl~du  
{ ,0Y5O?pu\  
try{ 4?^t=7N  
output = new DataOutputStream(new FileOutputStream(tmpFile)); F DCHB~D  
output.writeInt(nStartPos.length); B>&eciY  
for(int i=0;i<nStartPos.length;i++) .8%mi'0ud  
{ )vFZl
]  
// output.writeLong(nPos); (e;9,~u)  
output.writeLong(fileSplitterFetch.nStartPos); P>t[35/1  
output.writeLong(fileSplitterFetch.nEndPos); ZXj;ymC'  
} Tse Pdkk  
output.close(); XK5q
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} = A !;`G  
catch(IOException e){e.printStackTrace ();} t7p`A8
&  
catch(Exception e){e.printStackTrace ();} _}B:SM  
} R?Or=W)i  
|O]oX[~  
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//读取保存的下载信息（文件指针位置） -f-2!1&<3h  
private void read_nPos() :J}@*>c  
{
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try{ 5CsJghTw  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); J12ZdC'O  
int nCount = input.readInt(); #}A >B  
nStartPos = new long[nCount]; =Gq 'sy:h  
nEndPos = new long[nCount]; k(;c<Z{?1  
for(int i=0;i<nStartPos.length;i++) ^f,('0p->  
{ XHlx89v7  
nStartPos = input.readLong(); vK\;CSk  
nEndPos = input.readLong(); oGLSk(T&I  
} K>`7f]?H*e  
input.close(); )ccdfSe  
} 4%I(Z'*Cx  
catch(IOException e){e.printStackTrace ();} FT* o;&_QS  
catch(Exception e){e.printStackTrace ();} jbqhNsTNK  
} :oH"  
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.#b!#  
private void processErrorCode(int nErrorCode) $bU|'}QR  
{ x6ig,N~AO  
System.err.println("Error Code : " + nErrorCode); \8!&XcA  
} .#;;pu7W  
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?7cF_Zvve  
//停止文件下载 M9
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public void siteStop() @:. 6'ji,`  
{ o"x&F  
bStop = true; U!-|.N,  
for(int i=0;i<nStartPos.length;i++) j]"Yzt~u  
fileSplitterFetch.splitterStop(); URW'*\Xjb  
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} K`@GNT&  
} i%W,Y8\uf*  
//负责部分文件的抓取 `C`_2y8  
**FileSplitterFetch.java OwQ 9y<v  
*/ :!1B6Mc  
package NetFox; q
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H3.WAg[`  
import java.io.*; $2^V#GWo  
import java.net.*; 'Z7oPq6  
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public class FileSplitterFetch extends Thread { '7W?VipU  
m4nJ9<-  
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String sURL; //File URL +MQf2|--  
long nStartPos; //File Snippet Start Position A;h0BQ
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long nEndPos; //File Snippet End Position I,AI$A
 
int nThreadID; //Thread's ID UJ)\E ^Hp  
boolean bDownOver = false; //Downing is over t9PS5O ;  
boolean bStop = false; //Stop identical ?#\?&uFJ}  
FileAccessI fileAccessI = null; //File Access interface hSD)|  
 { Lt\4h  
f
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException r&\}E+  
{ +gOCl*L  
this.sURL = sURL; KTk%Np  
this.nStartPos = nStart; =? xA*_^  
this.nEndPos = nEnd; B{|P}fN5}  
nThreadID = id; c*_I1}l  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 _-Aw`<_*-  
} fZXJPy;n  
?/{ qRz'C<  
xGqe )M>8?  
public void run() a'Qy]P}'Ug  
{ LIVVb"V|,  
while(nStartPos < nEndPos && !bStop) /PIU@$DV  
{ A"C%.InZ  
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try{ \nx^=4*yk  
URL url = new URL(sURL); Xt8;Pl  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 1(!!EcU_  
httpConnection.setRequestProperty("User-Agent","NetFox"); o)?"P;UhJX  
String sProperty = "bytes="+nStartPos+"-"; q[q#cY:0  
httpConnection.setRequestProperty("RANGE",sProperty); KI$?0O  
Utility.log(sProperty); |zvxKIW;wd  
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InputStream input = httpConnection.getInputStream(); N:clwmo  
//logResponseHead(httpConnection); [ WZ<d^L  
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byte[] b = new byte[1024]; $Kb-mFR  
int nRead; FWdSpaas Q  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) >9=Y(`  
{ TRAs5I%  
nStartPos += fileAccessI.write(b,0,nRead); q?Q"Ab  
//if(nThreadID == 1) n\*>mp)  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); `
/]8C&u  
} =X>3C"]  
42Vy#t/HC  
*s?&)][  
Utility.log("Thread " + nThreadID + " is over!"); 8{JTR|yB  
bDownOver = true; : Ot\l  
//nPos = fileAccessI.write (b,0,nRead); _:M6~XHo  
} pLBp[GQ  
catch(Exception e){e.printStackTrace ();} J*,Ed51&7  
} c1CP12  
} Z5-"a?{Y  
$}OU~d1q  
0c7&J?"wE  
//打印回应的头信息 f;pR8  
public void logResponseHead(HttpURLConnection con) ~?-U J^#  
{ {*t'h?b  
for(int i=1;;i++) \p@,+ -gX  
{ ahS*YeS7  
String header=con.getHeaderFieldKey(i); }PyAmh$@  
if(header!=null) >}O1lsjW:z  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); X'jEI{1w  
Utility.log(header+" : "+con.getHeaderField(header)); nf/iZ &  
else [CRy>hfV  
break; cGsxfwD  
} 6l [TQ  
} lbT<HWzNH  
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public void splitterStop() xJ>hN@5}i  
{ c2?(.UV  
bStop = true; 52l|  
} MY9?957F  
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} z=>]E1'RL  
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/* #B`"B  
**FileAccess.java ?*,N ?s(U  
*//文件访问(定位，写) %~^R Iwm  
package NetFox; wxo(  
import java.io.*; w:'$Uf8]  
s.C-II?e  
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public class FileAccessI implements Serializable{ 5[X^1
 
;5"r)F+P  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ]ueq&|  
RandomAccessFile oSavedFile; [:g6gAuh,  
long nPos; Sqc*u&W  
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(sJ{27b_  
public FileAccessI() throws IOException :;{U2q+  
{ qdZn9i  
this("",0); Iy|]U&`  
} .yi.GRk  
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public FileAccessI(String sName,long nPos) throws IOException X_Y$-I$qd  
{ i0p"q p  
oSavedFile = new RandomAccessFile(sName,"rw"); MV9{>xX  
this.nPos = nPos; .__X[Mzth3  
oSavedFile.seek(nPos); b*dRNu  
} c0!bn b  
;?zb (2  
(.%:Q0i1  
public synchronized int write(byte[] b,int nStart,int nLen) 0~Yg={IKhK  
{ |`qur5h`  
int n = -1; ?PyI#G   
try{ /o8`I m   
oSavedFile.write(b,nStart,nLen); [^ 7^&/0  
n = nLen; <&l3bL  
} A8c'CMEm  
catch(IOException e) D9#e2ex]  
{ <po(7XB  
e.printStackTrace (); )]>=Uo  
} ]Z<{ ~  
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return n; Om>6<3n  
} JWMIZ{/M  
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} T{sw{E*  
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vx!nC}f"k`  
/*
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**SiteInfoBean.java !c(B^E  
*/ 7:M%w'oR  
package NetFox; qx0J}6+NlU  
I \vu?$w  
6G@_!i*2F  
public class SiteInfoBean { Ms^Y:,;Hi  
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private String sSiteURL; //Site's URL |P5?0{  
private String sFilePath; //Saved File's Path 86IAAO`#  
private String sFileName; //Saved File's Name eSa ]6  
private int nSplitter; //Count of Splited Downloading File xiA9X]FB  
_6=6 b!hD  
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public SiteInfoBean() ^Y #?@  
{//nSplitter的缺省值为5 0qJ(3N  
//default value of nSplitter is 5 bG.aV#$FIg  
this("","","",5); N1#*~/sXh  
} $D9JsUij  
F P mLost  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) YroKC+4"i  
{ zUwz[^d<C  
sSiteURL= sURL; %I6iXq#  
sFilePath = sPath; )v
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sFileName = sName; fKrOz!b  
this.nSplitter = nSpiltter; jew?cnRmd  
T=b5th}  
[(#ncR8B  
} iCl,7$[*  
Bj%{PK  
%\r4c*O1q  
public String getSSiteURL() 1!vR 8.  
{ (O&ooM* o  
return sSiteURL; P}?
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} U6.$F#n  
~73YOGiGJH  
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public void setSSiteURL(String value) bE]2:~  
{ M5Pvc  
sSiteURL = value; ]dk~C?H  
} lW^RwNcd  
_5.7HEw>/  
1S.nqOfx  
public String getSFilePath() (q:L_zFj>"  
{ lD !^MqK  
return sFilePath; <k<  
} v C><N  
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public void setSFilePath(String value) :j?Lil%R  
{ HlI*an  
sFilePath = value; q ,}W.
 
} 7*@qd&  
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public String getSFileName() q\mVZyj  
{ 6I_W4`<VeZ  
return sFileName; tM{t'WU  
} &*MwKr<y  
Qy@chN{eP  
zy+|)^E  
public void setSFileName(String value) a7OD%yQ  
{ 10}\7p8  
sFileName = value; &#;UKk~)Of  
} 0[9A*  
":eHR}Hzx  
XY0Gjo0  
public int getNSplitter() }1d 6d3b  
{ HAN#_B1.  
return nSplitter; `C] t2^  
} _j<46^  
#Du1(R  
7c4
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public void setNSplitter(int nCount) cq@8!Eu w]  
{ h7I_{v8  
nSplitter = nCount; qrm~=yU%  
} mpXco *!_  
} Ay2Vz>{  
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<P}{0Y~@*W  
/* >RF[0s'-  
**Utility.java $S=lm {  
*/ /-G;#Wm  
package NetFox; ~G5)ya-  
<\2,7K{{+;  
j"J2&Y2  
public class Utility { EV2whs2g  
ldi'@
^  
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public Utility() M/R#f9W  
{ J<u,Y= -~  
6D3fkvcZ  
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} Q[`_Y3@j  
RK"
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//线程睡眠 2$=?;~  
public static void sleep(int nSecond) 1&Nk  
{ Ok2k; +l  
try{ aq,&W q@  
Thread.sleep(nSecond); 6-QTqb?U;N  
} D8BK/E-  
catch(Exception e) MDl  
{ SDDs}mV  
e.printStackTrace (); HrEZ]iQ@O0  
} ?Z*LTsPr  
} Ny p5=  
%HwPOEJ  
//日志 >L?/Ph%d  
public static void log(String sMsg) K,?M5n '  
{ WLv( K_3Y  
System.err.println(sMsg); L?4c8!Q  
} _"##p  
gWv/3hWWB  
!T6oD]x3  
public static void log(int sMsg) <yE(p  
{ >77 /e@  
System.err.println(sMsg); qW$IpuK  
} G@ BrU q  
} <;phc~0+  
kO~xE-(=  
IAhyGD{b  
/* !`)
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**TestMethod.java T_y 'cvh  
*/ ) ?+-Z2BwA  
package NetFox; dkLc"$(O
 
>c5Vz^uM{4  
eIg ' !8h?  
public class TestMethod { zp,f}  
bx!Sy0PUJ  
'O \YL(j_e  
public TestMethod() 8/ZJkI  
{ ///xx/weblogic60b2_win.exe ^['%wA%  
try{ k2,n:7  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); -gv@ .#N  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); K>w}(td  
SiteFileFetch fileFetch = new SiteFileFetch(bean); <!-8g!  
fileFetch.start(); 2JUX29rER  
} xJJlVP  
catch(Exception e){e.printStackTrace ();} .G?7t6A  
-TjYQ  
"7l p|0I  
} J &u&G7#S  
*{)[:;  
C W7E2 ^P$  
public static void main(String[] args) FWq6e,  
{ gE`G3kgn{  
new TestMethod(); Rr|VGtg  
} vXq=f:y4  
} aVO5zR./)  
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