http断点续传简单实现（java)

/* pY~/<lzW  
**SiteFileFetch.java }Quk
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*/ U ;%cp  
package NetFox; R$|"eb5  
import java.io.*; {s7 3(B"  
import java.net.*; pie8 3Wy>  
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public class SiteFileFetch extends Thread { n^lr7(!6  
[r#m +R"N  
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SiteInfoBean siteInfoBean = null; //文件信息Bean z7X,5[P  
long[] nStartPos; //开始位置 Ndz'^c  
long[] nEndPos; //结束位置 {*PbD;/f  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 `R!%k]$  
long nFileLength; //文件长度 UdOO+Z_K%  
boolean bFirst = true; //是否第一次取文件 GBY-WN4sc[  
boolean bStop = false; //停止标志 #3knKBH  
File tmpFile; //文件下载的临时信息 +HT?>k  
DataOutputStream output; //输出到文件的输出流 Ur9L8EdC  
|Vo{ {
)  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） =]fOQN`  
public SiteFileFetch(SiteInfoBean bean) throws IOException .du2;`[$r  
{ 0FcG;i+  
siteInfoBean = bean; E[ttamU  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ]3Y J a  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); dQs>=(|t  
if(tmpFile.exists ()) r_hs_n!6  
{ Nu;?})tF  
bFirst = false; Ya `$.D  
read_nPos(); dKQu  
} .% 79(r^  
else %"Ia]0  
{ /.WIED}>  
nStartPos = new long[bean.getNSplitter()]; FnPn#Cv>*  
nEndPos = new long[bean.getNSplitter()]; z2lT4SAv+  
} }X/>WiGh:  
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} %i) 0sET  
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public void run() y(wb?86#W5  
{ >a;LBQ0  
//获得文件长度 ?PYZW5  
//分割文件 7~~suQ{F4  
//实例FileSplitterFetch |'``pq/}_  
//启动FileSplitterFetch线程 ;$67GK  
//等待子线程返回 yAFt|<  
try{ *nK4XgD  
if(bFirst) 29^(weT"]  
{ mT/^F{c  
nFileLength = getFileSize(); 'YJ~~o  
if(nFileLength == -1) cw,|,uXq 6  
{ PXG@]$~3  
System.err.println("File Length is not known!"); A34O(fE  
} D_?dy4\  
else if(nFileLength == -2) ;jJ4H+8  
{ <iBn-EG l>  
System.err.println("File is not access!"); @?jbah
#  
} g~2=he\C  
else  ^Kl*}  
{ DL#y_;#3_  
for(int i=0;i<nStartPos.length;i++)
@ULd~  
{ $o.;}  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); k8!:`jG  
} +,g!xv4Q  
for(int i=0;i<nEndPos.length-1;i++) DS9-i2  
{ (+6N)9rj`/  
nEndPos = nStartPos[i+1]; oWx^_wQ-=  
} A)gSOC{3F)  
nEndPos[nEndPos.length-1] = nFileLength; p({Lp}'  
} ]a`"O  
} {6O}E9  
;Ea8>  
N{}8Zh4op  
//启动子线程 V(XZ7<& {  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ]0O3kiVQ  
for(int i=0;i<nStartPos.length;i++) &grvlK  
{ 0_AIKJrL  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), {>PEl;,-  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), LqO=wK~  
nStartPos,nEndPos,i); cml~Oepf  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); aI=Q_}8-  
fileSplitterFetch.start(); DAg*  
} ,)N/2M\B-  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), &E
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); `A
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// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", acar-11_o/  
nEndPos = " + nFileLength); \3]O?'  
// fileSplitterFetch[nPos.length-1].start(); 1M6^Brx  
:x
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;y{(#X#  
//等待子线程结束 ..k8HFz>"  
//int count = 0; 6tjV^sjs  
//是否结束while循环 u.G aMl4 (  
boolean breakWhile = false; {;th~[  
@nMVs6  
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while(!bStop) ,jtaTG.
>  
{ X&| R\v=}  
write_nPos(); m`n~-_  
Utility.sleep(500); Q&+)Kp]A  
breakWhile = true; Xh}D_c  
|lZJt  
,%BDBZ  
for(int i=0;i<nStartPos.length;i++) >4-9 @i0FV  
{ hg:$H9\%  
if(!fileSplitterFetch.bDownOver) |:Maa6(W  
{ s[dIWYs#  
breakWhile = false; pq\N2d  
break; #D%6b  
} 4e;$+!dlV  
} * hS6F  
if(breakWhile) |W$|og'wC  
break; !f&hVLs0  
x,cvAbwS  
g]c6_DMfb1  
//count++; >M!LC  
//if(count>4) >dJ~  
// siteStop(); $-~"G,;F  
} nHH FHnFf  
~(yW#'G  
RLL%l  
System.err.println("文件下载结束！"); LH=^3Gw  
} NI.ROk1{+4  
catch(Exception e){e.printStackTrace ();} =$L+J O  
} =J]EVD   
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//获得文件长度 _dz ZS(7M6  
public long getFileSize() VCiq'LOR,<  
{ 5*-RIs! 2  
int nFileLength = -1; wfEL .h  
try{ )8eb(!}7  
URL url = new URL(siteInfoBean.getSSiteURL()); 5GgH6  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); rFkZ'rp74b  
httpConnection.setRequestProperty("User-Agent","NetFox"); `-{? !  
_x3=i\O,  
J~ome7L  
int responseCode=httpConnection.getResponseCode(); QxxPImubB  
if(responseCode>=400)
nnN$?'%~6  
{ IbL'Z   
processErrorCode(responseCode); G!=(^G@J;  
return -2; //-2 represent access is error ceD6q~)  
} %8%|6^,  
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~Dz:n]Vk/  
String sHeader; iWC}\&i  
@>.aQE  
iM;Btv[|  
for(int i=1;;i++) C4`&_yoP4-  
{ TQNdBq5I6  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 5
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//Utility.log(in.readLine()); 8!3q:8y8  
sHeader=httpConnection.getHeaderFieldKey(i); K@xMPB8in  
if(sHeader!=null) sJ^Ff  
{ aXQAm$/ >  
if(sHeader.equals("Content-Length")) -3~S{)  
{ \}u/0UF97  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 77sG;8HE  
break; pY3/AO=  
} #>\
SK  
} km5gO|V>m  
else );}M"W8  
break; &08dW9H  
} AB,(%JT/2{  
} E<u(Yw6=  
catch(IOException e){e.printStackTrace ();} E'D16Rhp  
catch(Exception e){e.printStackTrace ();} D_$N2>I-  
"eOl(TSu/  
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Utility.log(nFileLength); '%ZKvZ-  
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"nfi:A1  
return nFileLength; _z%~m2SP  
} qUmSB"#Z  
/ar0K9`c  
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//保存下载信息（文件指针位置） ni2 [K`  
private void write_nPos() $M0l (htR  
{ K;rgLj0m  
try{ v?6*n>R  
output = new DataOutputStream(new FileOutputStream(tmpFile)); +cYDz#3%  
output.writeInt(nStartPos.length); N#RC;  
for(int i=0;i<nStartPos.length;i++) W.cc!8  
{ nsXG@CS:  
// output.writeLong(nPos); 'm|T"Ym~  
output.writeLong(fileSplitterFetch.nStartPos); m;rr7{7X  
output.writeLong(fileSplitterFetch.nEndPos); b&4JHyleF  
} 8EdaqF  
output.close(); J?dz>3Rhx9  
} 4|5;nxkGm8  
catch(IOException e){e.printStackTrace ();} H<q|je}e  
catch(Exception e){e.printStackTrace ();} 09P2<oFLn  
} SDSP4W5  
c/^:vTF  
|Rx+2`6Dp  
//读取保存的下载信息（文件指针位置） R<Mp$K^b  
private void read_nPos() sUmpf4/  
{ 0[<'ygu  
try{ o$%KbfXO]  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); B:UPSX)A  
int nCount = input.readInt(); D$H&^,?N  
nStartPos = new long[nCount]; Eu
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nEndPos = new long[nCount]; HOH5_E>d  
for(int i=0;i<nStartPos.length;i++) "SQyy  
{ HN/YuP03[  
nStartPos = input.readLong(); :(/1,]bF  
nEndPos = input.readLong(); {E)tzBI;^  
} L8'4d'N+>  
input.close(); a_[+id  
} sm G?y
~  
catch(IOException e){e.printStackTrace ();} L[Y$ `e{zd  
catch(Exception e){e.printStackTrace ();} x5smJ__/  
} gN(kRhp  
:2NV;7Wke6  
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private void processErrorCode(int nErrorCode) Gx4uf  
{ &dj/
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System.err.println("Error Code : " + nErrorCode); {|<r7K1<  
} IQ~Anp^R  
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@V1FBw9S!@  
//停止文件下载 !nsr( 7X2  
public void siteStop() n[y^S3}%;  
{ ngd4PN>{4  
bStop = true; pBBKfv  
for(int i=0;i<nStartPos.length;i++) vfhoN]v  
fileSplitterFetch.splitterStop(); *M:p[.=1  
2Z<S^9O9  
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} eL)m(  
} 'aD"v>  
//负责部分文件的抓取 V8o, e  
**FileSplitterFetch.java NL-PQ%lUA  
*/ J?Q@f  
package NetFox; ;BWWafZ  
<.BY=z=H  
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import java.io.*; ef
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import java.net.*; Tb:'M:dM"  
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public class FileSplitterFetch extends Thread { UaQW<6
+  
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+mKII>{  
String sURL; //File URL h.- o$+Sa  
long nStartPos; //File Snippet Start Position r"x}=# b!  
long nEndPos; //File Snippet End Position i \lr KA  
int nThreadID; //Thread's ID Z.aeE*Hs$  
boolean bDownOver = false; //Downing is over ?G&J_L=@Y  
boolean bStop = false; //Stop identical ^$oEM0h  
FileAccessI fileAccessI = null; //File Access interface #q&Nd2y  
UA0( cK  
i#4E*B_-  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException vZ=dlu_t  
{ gMZrtK`<  
this.sURL = sURL; OH 88d:  
this.nStartPos = nStart; pm=s  
this.nEndPos = nEnd; _R ;$tG,  
nThreadID = id; 'Q*lp!2>  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 "zFTPL"  
} O=!EqaExW  
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('=Q[ua7-(  
public void run() 1x+w|h  
{ !|"LAr9u  
while(nStartPos < nEndPos && !bStop) ah!RQ2hDrV  
{ =`V9{$i  
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k)9 pkPl  
try{ cI<T/~P  
URL url = new URL(sURL); nqcD#HUv  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); = o1&.v2j  
httpConnection.setRequestProperty("User-Agent","NetFox");
q\fai^_  
String sProperty = "bytes="+nStartPos+"-"; ?V)M
!  
httpConnection.setRequestProperty("RANGE",sProperty); dW|S\
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Utility.log(sProperty); _uk
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>T29kgF2  
k]A$?C0Q<%  
InputStream input = httpConnection.getInputStream(); Bjb8#n04  
//logResponseHead(httpConnection); r$!  
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byte[] b = new byte[1024]; F4&`0y:  
int nRead; nqib`U@"  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) {'f=*vMI  
{ D}pNsQ  
nStartPos += fileAccessI.write(b,0,nRead); lXrAsm$  
//if(nThreadID == 1) 'c/Z
W  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); p=f8A71  
} m'L8z fX  
J|WkPv2  
/p[lOg  
Utility.log("Thread " + nThreadID + " is over!"); SBG.t:  
bDownOver = true; OjY#xO+'  
//nPos = fileAccessI.write (b,0,nRead); /q6 ^.>b  
} 2E=vMAS  
catch(Exception e){e.printStackTrace ();} ,Je9]XT  
} l Gy`{E|  
} ?\T):o;/  
!XrnD#  
&UoQ8&  
//打印回应的头信息 soB5sFt&]  
public void logResponseHead(HttpURLConnection con) sQr |3}I(  
{ w!/se;_H+w  
for(int i=1;;i++) L[p[m~HjG^  
{ Z3nmC-NE  
String header=con.getHeaderFieldKey(i); oi/bp#(fa  
if(header!=null) "_36WX  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Bis'59?U_  
Utility.log(header+" : "+con.getHeaderField(header)); pe7R1{2Q_s  
else YWUCrnr  
break; '/H+  
} d"hW45L  
} -PH!U Hg  
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A@k`$xevVj  
public void splitterStop() j`$d W H/2  
{ >z1q\cz  
bStop = true; d(8X?k.S  
} p$OkWSi~
 
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8 ,<F102(  
} xHY#"
 
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/* lZ` CFZR0
 
**FileAccess.java \z>L,U  
*//文件访问(定位，写) =]
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package NetFox; GH!Lu\y\  
import java.io.*; &e~g}7  
ct#3*]  
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public class FileAccessI implements Serializable{ MTxe5ob`$Q  
hs  m%o\  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 TUV&9wKXo  
RandomAccessFile oSavedFile; Nn%[J+
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long nPos; {"x8q  
o> i`Jq&  
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public FileAccessI() throws IOException a J&)-ge  
{ @L ,hA v^  
this("",0); 2!+saf^-,  
} qz .{[l  
?onTW2cG;  
i)pAFv<$,  
public FileAccessI(String sName,long nPos) throws IOException '*6S0zt  
{ !^:)zORYR  
oSavedFile = new RandomAccessFile(sName,"rw"); ;$Q&2}L[  
this.nPos = nPos; 9+o`/lk1  
oSavedFile.seek(nPos); n%J{Tcn6  
} U)n+j}vi  
^mA^7jB  
G(~ s(r{%I  
public synchronized int write(byte[] b,int nStart,int nLen) SQ_w~'(  
{ uGxh}'&  
int n = -1; M' d ,TV[  
try{ dfss_}R  
oSavedFile.write(b,nStart,nLen); XsVp7zk\  
n = nLen; -t:~d:  
} {xzs{)9|Y4  
catch(IOException e) #@#/M)  
{ !X5~!b^*  
e.printStackTrace (); Q,.[y"m9Y.  
} m1mA:R\zM  
7vRFF@eq}  
{O4y Y=G  
return n; cM= ?{W7~  
} |@a.dgz,  
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} &ZmHR^Flz  
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nsRZy0@$t  
/* =Qa*-*  
**SiteInfoBean.java yO7xAb  
*/ +EtL+Y(U  
package NetFox; U',9t  
? ^EB"{  
=sR]/XSK  
public class SiteInfoBean { }3"FQ/6C  
"o=*f/M  
: " ([i"  
private String sSiteURL; //Site's URL f^tCD'Vmi  
private String sFilePath; //Saved File's Path [%8t~zg  
private String sFileName; //Saved File's Name zSpL^:~  
private int nSplitter; //Count of Splited Downloading File ?\ qfuA9.  
qB`-[A9HPe  
&m>yY{be  
public SiteInfoBean() y?t2@f]!XK  
{//nSplitter的缺省值为5 RY>BP[h  
//default value of nSplitter is 5 #~ :j< =o  
this("","","",5); ]w3-No  
} AjTkQ)  
`W3;LTPEb  
b V)mO@N~w  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) b"au9:F4@7  
{ 7 +RsZu  
sSiteURL= sURL; [a\
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sFilePath = sPath; k63]Qf=5?N  
sFileName = sName; ]6`]+&  
this.nSplitter = nSpiltter; F~N
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NA%(ZRSg(  
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} DNP%]{J  
 h:[8$]  
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public String getSSiteURL() :'L^zGf  
{ yFIB/ln:  
return sSiteURL; VSK!Pc.G}
 
} *PXlbb  
$.a4Og2  
;1S~'B&1Q  
public void setSSiteURL(String value) @~4Q\^;NX  
{ F,t ,Ja  
sSiteURL = value; QY]^^f  
} 
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@Axwj
  
public String getSFilePath() r%M.rYLG{  
{ RXM
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return sFilePath; T-0[P;  
} $ekB+ t:cj  
W?a{3B   
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public void setSFilePath(String value) "pb$[*_@$  
{ eR'Df"+  
sFilePath = value; uXs.7+f  
} )c'5M]V  
x%acWeV5  
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public String getSFileName() kC=e>v  
{ < ag|
#  
return sFileName; VDCG 5QP6(  
} f0uzoeL<%  
QZcdfJck=+  
6m#V=4e*  
public void setSFileName(String value) 0?)U?=>]p  
{ ;Z\1PwT  
sFileName = value; KO`ftz3 +  
} G_GPnKdd  
OnNWci|7  
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public int getNSplitter() 9:|z^r  
{ j2V"w&>b}  
return nSplitter; _:hrm%^  
} %LeQpbyOR  
&PHejG_#  
]*I:N  
public void setNSplitter(int nCount) #;9I3,@/Y  
{ ^[K3]*!@  
nSplitter = nCount; <eU1E}BDQ  
} .\r=1HZ3  
} V$y6=Q<c  
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\8Mn[G9TL  
/* pGQ
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**Utility.java YCv)DW;  
*/ 6OBe^/ZRt  
package NetFox; ]V|rOtxb  
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/RVy?)hVT#  
public class Utility { gN2$;hb?  
~SI`%^L  
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public Utility() $]V,H"  
{ (HNxo{t  
D{-h2=V  
s)Gnj;  
} nkI+"$Rz0  
!n;0%"(FH  
//线程睡眠 f`ro{p  
public static void sleep(int nSecond) 4?+K:e #F  
{ @vsgm
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try{ #'poDX?  
Thread.sleep(nSecond); oRf.34  
} Hrjry$t/J  
catch(Exception e) ,;3bPjey  
{ to2;. ~X  
e.printStackTrace (); 1M1
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} $|kq{@<  
} <x Q
vS^|[  
o,-p[1b  
//日志 /{)}y  
public static void log(String sMsg) UB5CvM28  
{ Sb2hM~  
System.err.println(sMsg); _Y
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} 0+-"9pED>E  
+3>)r{#k  
QN4{xf:}S  
public static void log(int sMsg) .uh>S!X, ]  
{ CP]nk0  
System.err.println(sMsg); 0W_olnZ  
} :EGvI  
} O]-)?y/  
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/* W u C2LM  
**TestMethod.java ;JuBybJb  
*/ J-UqH3({Z,  
package NetFox; {yzo#"4Oy  
1"\^@qRv#  
0hNgr'  
public class TestMethod { /` ;rlH*  
^P!(*k#T  
>P9|?:c  
public TestMethod() e,?qwZK:y  
{ ///xx/weblogic60b2_win.exe ;aj4V<@  
try{ A"3"f8P8a  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 5i0vli/L  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); yI{4h $c  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ]lqe,>  
fileFetch.start(); !MyCxM6  
} <"hq}B  
catch(Exception e){e.printStackTrace ();} .)g7s? K  
Fa0NHX2:  
, 3&DA  
} S'_2o?fs  
4=nh' U38  
s~NJy'Y  
public static void main(String[] args) :|HCUZ*H(T  
{ <~bvfA=  
new TestMethod(); jmBsPSGIC  
} &SW~4{n:  
} [BTOs4f  
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