http断点续传简单实现（java)

/* -@Z9h)G|  
**SiteFileFetch.java vAjog])9s  
*/ !-t"}^)  
package NetFox; bnN&E?{hF1  
import java.io.*; W9]0X  
import java.net.*; *0m|`- T  
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public class SiteFileFetch extends Thread { :s1.TQ;Y(  
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SiteInfoBean siteInfoBean = null; //文件信息Bean /#j)GlNp:  
long[] nStartPos; //开始位置 `5
n^DP*X  
long[] nEndPos; //结束位置 SeuDJxqopD  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 !&5|:96o  
long nFileLength; //文件长度 (
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boolean bFirst = true; //是否第一次取文件 #)s +I2  
boolean bStop = false; //停止标志 iLNO}EUL  
File tmpFile; //文件下载的临时信息 O^8=Xj#}  
DataOutputStream output; //输出到文件的输出流 (yoF  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） @2`nBtk  
public SiteFileFetch(SiteInfoBean bean) throws IOException ng9_c  
{ Wu/:ES)C  
siteInfoBean = bean; `|mV~F|  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); qDgy7kkQ  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); goNDS5}  
if(tmpFile.exists ()) bK{ VjXF  
{ &'Xgf!x  
bFirst = false; ?v`24p3PC  
read_nPos(); JW"`i   
} }GHCu
 
else ?5F;4oR2g  
{ 3Kq/V_  
nStartPos = new long[bean.getNSplitter()]; ru|*xNXKgC  
nEndPos = new long[bean.getNSplitter()]; h-
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} x4,[5N"}YK  
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} A)&CI6(  
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public void run() I9xkqj  
{ FI~=A/:  
//获得文件长度 +G+1B6S  
//分割文件 7Hj7b:3K&!  
//实例FileSplitterFetch  bDD29  
//启动FileSplitterFetch线程 E33WT{H&_'  
//等待子线程返回 Bn.5ivF3  
try{ \jZ)r>US"  
if(bFirst) ]@~%i=.7  
{ U }I#;*F  
nFileLength = getFileSize(); "p+JME(  
if(nFileLength == -1) @LSX@V   
{ u|k_OUTq  
System.err.println("File Length is not known!"); f{uS  
} ;f=.SJF  
else if(nFileLength == -2) GL,[32~C  
{ gSf>+|  
System.err.println("File is not access!"); ^z~drcR  
} 1 |/ |Lq%w  
else h")7kjM  
{ tY:,9eh7B  
for(int i=0;i<nStartPos.length;i++) _xBhMu2f  
{ Aj
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); ZE1${QFkG  
} B>sQcZ:  
for(int i=0;i<nEndPos.length-1;i++) hjhZ":I.  
{ t_Rj1U  
nEndPos = nStartPos[i+1]; JB=L{P J  
} 43<i3O  
nEndPos[nEndPos.length-1] = nFileLength; |?hsMN  
} 8k+k\V{  
} `b%^_@Fb  
D *IeG>%  

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//启动子线程 lkC|g
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; |C5{[ z  
for(int i=0;i<nStartPos.length;i++) JY,oXA6O  
{ FlY"OU*  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), j`K0D65  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ,?`kYPZ  
nStartPos,nEndPos,i); ly6dl
 
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); [Dmf.PUe  
fileSplitterFetch.start(); fwh/#V-i  
} +q+JOS]L  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), F&B E+b/#  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); m=Mk@xfQ#  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", y=jZ8+M   
nEndPos = " + nFileLength); RD;A  
// fileSplitterFetch[nPos.length-1].start(); UMT}2d%  
B\l0kiNT  
zMM~4?4  
//等待子线程结束 .u`A4;;Gw  
//int count = 0; {xOzxLB;  
//是否结束while循环 }SyK)W5Y  
boolean breakWhile = false; i6y=3k  
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q8
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while(!bStop) 3#GIZL}!x  
{  *I}_g4  
write_nPos(); qT&zg@m  
Utility.sleep(500); oel?we6  
breakWhile = true; wDW/?lT&  
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for(int i=0;i<nStartPos.length;i++) de[NIDA;`  
{ `LKf$cx(A  
if(!fileSplitterFetch.bDownOver) ;%cW[*Dw  
{ 25r3[gX9`  
breakWhile = false; '@IReMl  
break; 2=%]Ax"R  
} .9Dncsnf,`  
} N9M",(WTt}  
if(breakWhile) Vup|*d2r0E  
break; -KfMKN~  
z4zPR?%:  
:bL^S1et  
//count++; x}=Q)|)]  
//if(count>4) WM4,\$  
// siteStop(); |KO[[4b ?+  
} oa[O~z{~  
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System.err.println("文件下载结束！"); !f}D*8\f  
} KTAQ6k  
catch(Exception e){e.printStackTrace ();} &7\fj  
} fu-,<m{  
K4I/a#S'@6  
2L51H(  
//获得文件长度 M a3}w-=;  
public long getFileSize() H6Gs&yk3  
{ h##U=`x3  
int nFileLength = -1; =H}x  
try{ c>Ri6=C  
URL url = new URL(siteInfoBean.getSSiteURL()); =Lnip<t>ja  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); sM%l:Fv  
httpConnection.setRequestProperty("User-Agent","NetFox"); 8-cuaa  
D
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6\.LG4@LO  
int responseCode=httpConnection.getResponseCode(); _::ssnG3jT  
if(responseCode>=400) :@@m'zF<;  
{ L>0Pur)[  
processErrorCode(responseCode); DG&aFmC  
return -2; //-2 represent access is error B@ msGb C  
} tCA0H\';  
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String sHeader; Ug4o2n0sk  
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for(int i=1;;i++) kjXwVGK=P<  
{ s?4nR:ZC}  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); cmq4w&x/  
//Utility.log(in.readLine()); e-1G\}E  
sHeader=httpConnection.getHeaderFieldKey(i); 'q RQO(9&m  
if(sHeader!=null) +oHbAPs8  
{ NW*#./WdF8  
if(sHeader.equals("Content-Length")) 8U7dd[  
{ Lr=
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nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ,}9 tJY@E  
break; h
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} 6Tc!=lk  
} E}<i?;  
else ~&+a.@T  
break; eZ0-O /_i  
} >p" U|  
} oq|`;k   
catch(IOException e){e.printStackTrace ();} _A0X[}^K  
catch(Exception e){e.printStackTrace ();} )_?h;wh 84  
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Utility.log(nFileLength); "=JE12=u  
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return nFileLength; 7KJ0>0~Et  
} ={;+0Wj
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//保存下载信息（文件指针位置） ?{5}3abB`  
private void write_nPos() X|QokAR{$>  
{ L{&=SR.  
try{ {z;4t&5  
output = new DataOutputStream(new FileOutputStream(tmpFile)); " SP6o  
output.writeInt(nStartPos.length); A..`?oGj  
for(int i=0;i<nStartPos.length;i++) !,]c}Y{i  
{ [F(iV[n%  
// output.writeLong(nPos); {vZAOz7#  
output.writeLong(fileSplitterFetch.nStartPos); u`Y~r<?P(  
output.writeLong(fileSplitterFetch.nEndPos); d\tY-X3  
} FV,aQ#  
output.close(); Dca,IaT'  
} H0.A;`  
catch(IOException e){e.printStackTrace ();} -
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catch(Exception e){e.printStackTrace ();} Z+[W@5q  
} f/4DFs{  
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.j=mT[N,I  
//读取保存的下载信息（文件指针位置） 'op_GW  
private void read_nPos() ]<c\+9  
{ .~q>e*8AH  
try{ /^bU8E&^M  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); NA`8 ^PZ  
int nCount = input.readInt(); g-NrxyTBlx  
nStartPos = new long[nCount]; ra_v+HR7  
nEndPos = new long[nCount]; Iek]/=  
for(int i=0;i<nStartPos.length;i++) %T\2.vl  
{ J8Vzf$t};  
nStartPos = input.readLong(); Gi2Fjq/Y  
nEndPos = input.readLong(); *Tr{a_{~C  
} 8F's9c,  
input.close(); } j;es(~D  
} EQ|Wke  
catch(IOException e){e.printStackTrace ();} L.}sN.  
catch(Exception e){e.printStackTrace ();} "*(a2k3J  
} ~ tN/  
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{y%@1q%"  
private void processErrorCode(int nErrorCode) vg_PMy\  
{  x\VP X  
System.err.println("Error Code : " + nErrorCode); bka%W@Y%  
} Fdq5:v?k  
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//停止文件下载 oEj$xm_}  
public void siteStop() BW`;QF<  
{ U)Tl<l<  
bStop = true; vz1I/IdTd  
for(int i=0;i<nStartPos.length;i++) #TH(:I=[  
fileSplitterFetch.splitterStop(); .C ,dV7  
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} |B64%w>Y  
} K]|hkp&  
//负责部分文件的抓取 mQ:YHtHE.F  
**FileSplitterFetch.java a$bE2'cb  
*/ ,]das  
package NetFox; +>$Kmy[3  
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import java.io.*; t%f>*}*P*  
import java.net.*; xh!T,|IR  
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public class FileSplitterFetch extends Thread { vGI)c&C>  
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String sURL; //File URL }jdmeD:  
long nStartPos; //File Snippet Start Position Cn5;h(r  
long nEndPos; //File Snippet End Position r)Ml-r=  
int nThreadID; //Thread's ID W`TSR?4~t?  
boolean bDownOver = false; //Downing is over `gJ$fTi&  
boolean bStop = false; //Stop identical T,PN6d  
FileAccessI fileAccessI = null; //File Access interface hb)C"q=  
%[azMlp<  
*!3qO^b?  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException pZt>rv  
{ Hc8!cATQk  
this.sURL = sURL; J6rWe  
this.nStartPos = nStart; %,aSD#l`f  
this.nEndPos = nEnd;
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nThreadID = id; &yOl}?u  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 T\:*+W37  
} &Mt
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dNov= w  
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public void run() x(~V7L>"i  
{ Ap|g[J  
while(nStartPos < nEndPos && !bStop) ZW@cw}  
{ IMzt1l =7  
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a( N;|<  
try{ @uG/2'
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URL url = new URL(sURL); x;LO{S4Z  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); b5f+q:?{  
httpConnection.setRequestProperty("User-Agent","NetFox"); B+pLW/4l  
String sProperty = "bytes="+nStartPos+"-"; 'UZ i>Ta  
httpConnection.setRequestProperty("RANGE",sProperty); =@X?$>'  
Utility.log(sProperty); Y@T$O<*  
'0&HkM{ D  
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InputStream input = httpConnection.getInputStream(); %kgT=<E'  
//logResponseHead(httpConnection); j_0l'Saj  
m#RMd,'X  
+OtD@lD`!  
byte[] b = new byte[1024]; ((^vsKT  
int nRead; `Ao"fRv#  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) +$/NTUOP  
{ #yE
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nStartPos += fileAccessI.write(b,0,nRead); vu*9(t)EC  
//if(nThreadID == 1) [lK`~MlQ  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Z^mQb2e.  
} R$+"'N6p  
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Utility.log("Thread " + nThreadID + " is over!"); ^$RpP+d  
bDownOver = true; X?/32~\  
//nPos = fileAccessI.write (b,0,nRead); _.%g'=14f  
} n3 Rf:j^R  
catch(Exception e){e.printStackTrace ();} K 6,c||#<  
} Uv=)y^H~*A  
} 8p1:dTI5Pb  
d(|4 +^>  
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//打印回应的头信息 `FX?P`\@I  
public void logResponseHead(HttpURLConnection con) w]
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{ [=u@6Y  
for(int i=1;;i++) !vHCftKel  
{ &?}h)
U#:  
String header=con.getHeaderFieldKey(i); F*NHy.Y  
if(header!=null) (/t{z=  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); vy>(?[  
Utility.log(header+" : "+con.getHeaderField(header)); h96<9L  
else Lw?>1rTT/  
break; V|{~9^  
} gI@nE:(m  
} NL!xkcXO  
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public void splitterStop() 4FKgp|Y0  
{
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bStop = true; yWr&G@>G  
} r"\<+$ 7  
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} 0$U\H>r  
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M.C`nI4  
/* zW.Ltz  
**FileAccess.java
y\dx \  
*//文件访问(定位，写) oB'5':  
package NetFox; th0>u.hJ  
import java.io.*; >km$zfM2-  
pNu?DF{ 3  
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public class FileAccessI implements Serializable{ %0f*OC  
[RTo[-ci2  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 V_|
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RandomAccessFile oSavedFile; xZloEfv.B  
long nPos; U-{3HHA  
S>"
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public FileAccessI() throws IOException ^lK!tOeO  
{ yC!>7@m  
this("",0); D?H|O[  
} gs~u8"B  
piIG
SC  
(?.h<v1}  
public FileAccessI(String sName,long nPos) throws IOException ?b(DDQMf  
{ M,Lq4bz  
oSavedFile = new RandomAccessFile(sName,"rw"); f.R;<V.)  
this.nPos = nPos; R m2M  
oSavedFile.seek(nPos); n~i^+pD@  
} gDX\ p>7  
>9<rc[  
XqcNFSo)  
public synchronized int write(byte[] b,int nStart,int nLen) |UcF%VNnz1  
{ 7a.iT-*  
int n = -1; Vu<mOuh
 
try{ OSC_-[b-  
oSavedFile.write(b,nStart,nLen); Dd$8{~h"G  
n = nLen; azTiY@/  
} ZMK1V)ohn  
catch(IOException e) kkj_k:Eah  
{ $u)#-X;x  
e.printStackTrace (); fRzJiM{  
} T+!0`~`  
s>TC~d82  
x LK,Je  
return n; &Mz.i,Gh  
} /[q_f  
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} JNu+e#.Y  
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/* t*c_70|@k  
**SiteInfoBean.java g+C~}M_7  
*/ CY!H)6k  
package NetFox; Nk9w; z&  
aZta%3`)  
gf8~Zlq4v  
public class SiteInfoBean { mDWRYIuN  
 Y@b|/+  
4%u\dTg/B  
private String sSiteURL; //Site's URL #"o`'5  
private String sFilePath; //Saved File's Path ~BXy)IB6  
private String sFileName; //Saved File's Name ?.nD!S@  
private int nSplitter; //Count of Splited Downloading File _Vr}ipx-k  
uU+?:C  
!B#tJD  
public SiteInfoBean() UXHtmi|_:  
{//nSplitter的缺省值为5 P;ZVv{mT  
//default value of nSplitter is 5 %V-Hy;V  
this("","","",5); C{V,=Fo^  
} /T 4GPi\lg  
|j$$0N  
8: VRq  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) :~,V+2e  
{ k{^iv:  
sSiteURL= sURL; df$pT?o  
sFilePath = sPath; \T;(k?28HN  
sFileName = sName; R~#&xfMd.  
this.nSplitter = nSpiltter; " _TAo  
5N|hsfkx  
NRe=O*O  
} T<mP.T,$!  
*o=( w5   
2j[;M-3  
public String getSSiteURL() 2(Nf$?U@0  
{
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return sSiteURL; m;u:_4  
} s 8lfW6  
h-*h;Uyc  
+a'nP=e&  
public void setSSiteURL(String value) P0-K/_g  
{ \Iz-<:gA'  
sSiteURL = value; F=;nWQ&  
} DM{Z#b]  
"s\himoa  
Lo +H&-  
public String getSFilePath() 
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{ s09&A]G  
return sFilePath; _2<d6@}
 
} kM(,8j  
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^O3p:X4u  
public void setSFilePath(String value) |b|bL 7nx  
{ U+@rLQ.-  
sFilePath = value; :2;c@ uj  
} -L2%,.E>4  
zY&/lWW._  
I -V=Z:  
public String getSFileName() z*/}rk4i  
{ f5#VU7=1F2  
return sFileName; %){)/~e&  
} Gg5>~"pb  
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:j;_Xw  
public void setSFileName(String value) 28 ;x5m)N  
{ HgOrrewj  
sFileName = value; N<aMUVm  
} FC8#XZp  
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dca?(B!'6  
public int getNSplitter() 8?t}S2n2  
{ l'"Ici#7Ls  
return nSplitter; ztV%W6  
} ^FK-e;J  
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public void setNSplitter(int nCount) w?M` gl8r  
{ >jm^MS=  
nSplitter = nCount; x
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} Xxs0N_va&  
} b|g=&T:pp  
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1K{hj%  
/* h%U,g 9_  
**Utility.java \l/<[ZZ  
*/  *l-F  
package NetFox; ++d[YhO  
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S~.%G)R  
public class Utility { `FIS2sl/  
<
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public Utility() Dmn{ppfyb  
{ ]{pH,vk-  
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} 8>ODtKI*  
4 _Idf  
//线程睡眠 6Zq7O\  
public static void sleep(int nSecond) | <- t  
{ biAa&  
try{ nbSu|sX~r5  
Thread.sleep(nSecond); HmRmZ3~  
} ZgL]ex  
catch(Exception e) XM?C7/^k  
{ 3qrjb]E%}  
e.printStackTrace (); a*Ng+~5)6  
} p/Lk'h~  
} 0J1&6b  
Hc-Ke1+  
//日志 &^])iG,Ew  
public static void log(String sMsg) -y)g}D%  
{ OG2&=~hOz-  
System.err.println(sMsg); wXUgxa  
} LKu ,H  
IFF3gh42.  
RJA#cv~f  
public static void log(int sMsg) WlnS.P\+E  
{ )W3kBDD  
System.err.println(sMsg); D? FWSv  
} uE,j$d  
} "o$)z'q
 
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/* ~DUOL~E  
**TestMethod.java `Bv, :i  
*/ ')~[J$qz  
package NetFox; ^TCfj^FP  
-n`2>L1  
D>"!7+t|@a  
public class TestMethod { iLJBiZ+  
Ox"SQ`nSj'  
%1%@L7wP>  
public TestMethod() ]j^rJ|WTH  
{ ///xx/weblogic60b2_win.exe OJPi*i5*  
try{ c:_dW;MJ0  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ;F\sMf{  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); >&uR=Yd  
SiteFileFetch fileFetch = new SiteFileFetch(bean); $D(q  
fileFetch.start(); 2"L a}Vx2  
} aD
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catch(Exception e){e.printStackTrace ();} kaZ_ra;<  
>Mk#19j[/  
qc@v"pIz'S  
} bn0Rv  
aq%i:};  
iGsD!2  
public static void main(String[] args) h v/+  
{ |FJc'&)J"  
new TestMethod(); YfU6mQ  
} 'n!kqP  
} rd4mAX6@  
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