http断点续传简单实现（java)

/* Xpa;F$VI  
**SiteFileFetch.java v:vA=R2  
*/ ^X_%e|  
package NetFox; W&*{j;e9%I  
import java.io.*; t4JGd)r  
import java.net.*; J,q:  
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public class SiteFileFetch extends Thread { JN8k x;@  
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SiteInfoBean siteInfoBean = null; //文件信息Bean oZ8SEC"]  
long[] nStartPos; //开始位置 AG9U2x  
long[] nEndPos; //结束位置 =*(d+[_  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 xQD#; 7  
long nFileLength; //文件长度 G's/Q-'[\  
boolean bFirst = true; //是否第一次取文件 D~%cf  
boolean bStop = false; //停止标志 )q=1<V44d  
File tmpFile; //文件下载的临时信息 JRo{z{!O6  
DataOutputStream output; //输出到文件的输出流 V,Gt5lL&/!  
aI\VqOt]  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） O{dx+f  
public SiteFileFetch(SiteInfoBean bean) throws IOException 2N]y)S_<V  
{ Ny~;"n  
siteInfoBean = bean;
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//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); M.128J+xfS  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); -S|L+">=Z  
if(tmpFile.exists ()) ,{oANqP  
{ d3![b1  
bFirst = false; 5(F!*6i>  
read_nPos(); :J<S-d=  
} \e=@h!p  
else P_?1Rwm-45  
{ [lnN~#(Y  
nStartPos = new long[bean.getNSplitter()]; t4<#k=  
nEndPos = new long[bean.getNSplitter()]; QHQj6]
 
} % ,X(GwX  
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} kO5KZ;+N-  
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public void run() J L Z  
{ \Js9U|lY  
//获得文件长度 =X1$K_cN  
//分割文件 t=pG6U  
//实例FileSplitterFetch #uH1!UQb  
//启动FileSplitterFetch线程 HD`%Ma Yhc  
//等待子线程返回 hyBSS,I  
try{ ;w+A38N$J  
if(bFirst) ;WzT"yW)T  
{ j`#|z9`(pB  
nFileLength = getFileSize(); H,?MG  
if(nFileLength == -1) : i(h[0  
{ :Ert57@l  
System.err.println("File Length is not known!"); Wm\f:|U5`  
} `"bm Hs7  
else if(nFileLength == -2) ())|x[>JS+  
{ oZ=e/\[K  
System.err.println("File is not access!"); G>!"XK:fB  
} Lr+2L_/v`  
else 7f(UbO@BD  
{ QvqBT  
for(int i=0;i<nStartPos.length;i++) ~+d]yeDrhx  
{ i|=XW6J%  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); cvC;QRx  
} Npu;f>g0_  
for(int i=0;i<nEndPos.length-1;i++) :2?'mKa7  
{ %TR->F  
nEndPos = nStartPos[i+1]; q)%C
|  
} /TB_4{  
nEndPos[nEndPos.length-1] = nFileLength; 6^
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} C :e 'wmA  
} 2z-&Ya Qu  
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//启动子线程 dXOjaS# ~  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; {6KU.'#iF  
for(int i=0;i<nStartPos.length;i++) 5i#B?+Y  
{ Y
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fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 9sRP8Nj|  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ?,Hk]Rl3  
nStartPos,nEndPos,i); -x RsYYw  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); UIyOn` d"  
fileSplitterFetch.start(); |M0TG  
} *Lufz-[1  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(),
`t8e2?GH  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 6qw_|A&g  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", aTPpE9Pa&  
nEndPos = " + nFileLength); vCi:cIp/  
// fileSplitterFetch[nPos.length-1].start(); d }]b  
k"n
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//等待子线程结束 Ig6s'^
  
//int count = 0; pGOS'.K%t8  
//是否结束while循环 %+'&
$  
boolean breakWhile = false; UM#]olh  
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}??q{B@v  
while(!bStop) ~L1N1Z)Kk  
{ p@^2.O+  
write_nPos(); jLEU V  
Utility.sleep(500); =N3~2=g~A  
breakWhile = true; Mr&]RTEE  
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for(int i=0;i<nStartPos.length;i++) 9\"
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{ Mc\lzq8\ 1  
if(!fileSplitterFetch.bDownOver) &hF>}O  
{ mg3jm  
breakWhile = false; iffU}ce  
break; E O}(MXS  
} p3Gj=G  
} L,:U _\HQ  
if(breakWhile) Ea3tF0{  
break; G{s ,Y^  
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//count++; H37Z\x
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//if(count>4) ?Jma^ S  
// siteStop(); q!7\`>.2:{  
} kC#;j=K?  
v<-D>iJ  
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%  
System.err.println("文件下载结束！"); ROfmAc  
} .Kv@p jOr  
catch(Exception e){e.printStackTrace ();} O}%=c\Pb  
} <Q8bn?Z  
NR3IeTd  
)-sEm`(`I9  
//获得文件长度 eygyVhJ  
public long getFileSize() ES+&e/G"ds  
{ @.gCeMlOf  
int nFileLength = -1; .)o5o7H  
try{ 'IgtBd|K>  
URL url = new URL(siteInfoBean.getSSiteURL()); a@X'oV`(2b  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); LRmO6>y  
httpConnection.setRequestProperty("User-Agent","NetFox"); |n~v_V2.0  
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int responseCode=httpConnection.getResponseCode(); '|+_~ZO*d  
if(responseCode>=400) =GpLlJ`-  
{ mHhm~u  
processErrorCode(responseCode); ]A\n>Z!;  
return -2; //-2 represent access is error {!="PnB  
} %?g]{  
{7;TQ?/  
|;].~7^  
String sHeader; Lf,gS*Tg?  
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for(int i=1;;i++)
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{ _,'UP>
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//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); m1cyCD  
//Utility.log(in.readLine()); 7z$+ *]9-  
sHeader=httpConnection.getHeaderFieldKey(i); v:+se6HY?p  
if(sHeader!=null) 4SOj>(a#  
{ ]F_u  
if(sHeader.equals("Content-Length")) S !e0:  
{ ]f\rB8k|&  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); o 1b#q/  
break; 8=e\^Q+  
} z4<h)hh"k6  
} A76=^iw  
else R:fu n,  
break; O=mJ8W@  
} i44`$ps  
} >,y QG+  
catch(IOException e){e.printStackTrace ();} c[YC}@l%a  
catch(Exception e){e.printStackTrace ();} Xak~He  
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Utility.log(nFileLength); U-Iwda8v  
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return nFileLength; abK/!m[q  
} B^OhL!*tI  
IQ|~d08}  
t]m#k%)  
//保存下载信息（文件指针位置） 
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private void write_nPos() B>'\g O\2  
{ C2VZE~U+  
try{ i^W\YLE  
output = new DataOutputStream(new FileOutputStream(tmpFile)); .d*vfE$  
output.writeInt(nStartPos.length); g,1\Gj%y  
for(int i=0;i<nStartPos.length;i++) _7;#0B  
{
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// output.writeLong(nPos); #8(@a Y  
output.writeLong(fileSplitterFetch.nStartPos); ugL$W@   
output.writeLong(fileSplitterFetch.nEndPos); C{,nDa?|  
} d9^h YS{  
output.close(); `Ffn:=Do  
} 8<o(z'&y  
catch(IOException e){e.printStackTrace ();} mT9TSW}  
catch(Exception e){e.printStackTrace ();} R{WG>
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} $`riB$v  
^yfT7050  
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//读取保存的下载信息（文件指针位置） 0 8U:{LL  
private void read_nPos() F!Uk`[L  
{ .z9JoQ  
try{ #A|MNJ%m  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Axcm~!uf  
int nCount = input.readInt(); i\3
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nStartPos = new long[nCount]; R` N-^x  
nEndPos = new long[nCount]; BEY}mR]  
for(int i=0;i<nStartPos.length;i++) )S5Q5"j&=f  
{ U2h?l `nP  
nStartPos = input.readLong(); LsmC/+7r$1  
nEndPos = input.readLong(); YS/DIH{9e  
} <?I~ +  
input.close(); 1M
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} ^,rbA>/L  
catch(IOException e){e.printStackTrace ();} m!PN1$9V  
catch(Exception e){e.printStackTrace ();} h qxe  
} m=#2u4H4  
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private void processErrorCode(int nErrorCode) BeVQ[  
{ a~{mRh  
System.err.println("Error Code : " + nErrorCode); r..Rh9v/=E  
} HWc=.Q
q  
8'f:7KF  
*f,EDSN1@d  
//停止文件下载 +DU}f;O8v  
public void siteStop() 8J@REP4  
{ jbG #__#_  
bStop = true; .<tb*6rX>  
for(int i=0;i<nStartPos.length;i++) VbZZ=q=Kd  
fileSplitterFetch.splitterStop(); :*\JJ w  
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} ? 1_*ct=g9  
} khyVuWN  
//负责部分文件的抓取 y0z}[hZ  
**FileSplitterFetch.java jPFA\$To  
*/ U/TF,JUI  
package NetFox; yJ?4B?p(  
d#A.A<p*  
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import java.io.*; +.zriiF]i  
import java.net.*; RCsd  
+H+OYQ>^  
9/0<Z_b2  
public class FileSplitterFetch extends Thread { [5,#p$R  
7q(RQQp  
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String sURL; //File URL O>}aK.
H  
long nStartPos; //File Snippet Start Position 3Hr ZN+D  
long nEndPos; //File Snippet End Position p6sXftk  
int nThreadID; //Thread's ID ]r|X[9  
boolean bDownOver = false; //Downing is over SkS vu}  
boolean bStop = false; //Stop identical Id9hC<8$dq  
FileAccessI fileAccessI = null; //File Access interface teET nz_L  
N 0`)WLW  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException X\uN:;?#W{  
{ l].dOso$`  
this.sURL = sURL; O,hT< s "  
this.nStartPos = nStart; VBy=X\w]  
this.nEndPos = nEnd; V:yia^1  
nThreadID = id; \]GBd~i<  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 j]YS(Y@AY  
} >+&524xc  
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public void run() =r#of|`Q  
{ \y{C>!WX4  
while(nStartPos < nEndPos && !bStop) @/7tN3O  
{ eR=P  
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try{ g&X$)V4C  
URL url = new URL(sURL); 4y:yFTp  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); |&3[YZY  
httpConnection.setRequestProperty("User-Agent","NetFox"); y&UcTE2;%(  
String sProperty = "bytes="+nStartPos+"-"; N<9CV!_  
httpConnection.setRequestProperty("RANGE",sProperty); R9^Vk*`gFU  
Utility.log(sProperty); RYy_Ppn96f  
+AO(e  
A-qdTJP  
InputStream input = httpConnection.getInputStream(); pm@Mlwg`1  
//logResponseHead(httpConnection); zcy!YB  
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byte[] b = new byte[1024]; +q6/'ErN]m  
int nRead; A+_361KH  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop)  GMrjZ  
{ B&VruOP0  
nStartPos += fileAccessI.write(b,0,nRead); ~4<xTP\*  
//if(nThreadID == 1) >2tYw,m  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); VMZ\9IwI  
} ~#C7G\R  
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Utility.log("Thread " + nThreadID + " is over!"); wL\OAM6R  
bDownOver = true; "@#^/m)  
//nPos = fileAccessI.write (b,0,nRead); Rq|7$O5  
} >;LXy  
catch(Exception e){e.printStackTrace ();} M2l0x @|  
} 'H0uvvhOp  
} k+t?EZ6L  
j KGfm9|zj  
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//打印回应的头信息 ;=fOyg  
public void logResponseHead(HttpURLConnection con) \oA>%+]5  
{ 3rBSwgRl  
for(int i=1;;i++) gY|f[M|  
{ \!x~FVA  
String header=con.getHeaderFieldKey(i); ~=67#&(R  
if(header!=null) bnIl@0Y  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); &e0BL z  
Utility.log(header+" : "+con.getHeaderField(header)); m&a.i B  
else W US[hx,  
break;  qr~P$  
} Jz
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} 98'/yZ  
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public void splitterStop() piULIZ0  
{ ])`w_y(>  
bStop = true; %Ya%R@b}  
} W8,4LxH  
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} `ECY:3"$KA  
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/* <hkSbJF  
**FileAccess.java ]ie38tX$  
*//文件访问(定位，写) B>C+qj@  
package NetFox; =S+*=jA  
import java.io.*;  Z(F['Zf  
[ICFPY6  
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public class FileAccessI implements Serializable{ IyK^` y  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 8z1#Q#5  
RandomAccessFile oSavedFile; WVZ](D8Gc]  
long nPos; [`J91=  
lDsT?yHS`Z  
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public FileAccessI() throws IOException O2{~Q{p  
{  ddK\q!0  
this("",0); iq1HA.X(  
} .bYZkO:oy  
/{Mo'.=Z  
03
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public FileAccessI(String sName,long nPos) throws IOException <fSWX>pR  
{ aW=c.Q.  
oSavedFile = new RandomAccessFile(sName,"rw"); @I"&k!e<2  
this.nPos = nPos; 0{Uc/  
oSavedFile.seek(nPos); Eqizx~eqq  
} pKZRgA#kN  
RW-)({  
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public synchronized int write(byte[] b,int nStart,int nLen) c~``)N  
{ f4 k  
int n = -1; e'I/}J  
try{ (/gv U80  
oSavedFile.write(b,nStart,nLen); cV$an  
n = nLen; $Z|
HFV{  
} FP=up#zl  
catch(IOException e) ,ArHS  
{ qPQ6`rD\  
e.printStackTrace (); Nwwn #+  
} )fy-]Ky *  
r{>`"  
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return n; 2x5^kN7  
} (n{x"rLy/  
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} &zR\Rmpt  
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/* 9epMw-)k  
**SiteInfoBean.java
/9pN.E  
*/ YjCHKI"e  
package NetFox; o;TS69|D  
VQ"Z3L3-4  
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public class SiteInfoBean { ?kIyo  
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private String sSiteURL; //Site's URL -1{f(/  
private String sFilePath; //Saved File's Path 'Z*`~,Q  
private String sFileName; //Saved File's Name +0ALO%G;G"  
private int nSplitter; //Count of Splited Downloading File Tbp;xv_qo  
v!`:{)2C  
&HQ_e$1  
public SiteInfoBean() $PstE
L  
{//nSplitter的缺省值为5 ?:tk8Kgf  
//default value of nSplitter is 5 %lk^(@+ T  
this("","","",5); DFkDlx  
} bN\;m^xfu  
u\{MQB{T  
{^D; ($lm  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) z+Guu8  
{ v,'k2H  
sSiteURL= sURL; ;kI)j ?  
sFilePath = sPath; 4Ei8G]O $_  
sFileName = sName; t[r6jo7  
this.nSplitter = nSpiltter; Sa[?B  
=X1oB,W{  
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} `w&?SXFO8  
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public String getSSiteURL() Kf-XL),3l  
{ O3V.4tp  
return sSiteURL; ZO!h!2*  
} F EUfskv  
AGl#f\_^  
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public void setSSiteURL(String value) s~QIs  
{ 7Ll?#eun  
sSiteURL = value; Q45gC28x  
} QQ`tSYgex  
m@Dra2Cv'@  
o~<jayqU  
public String getSFilePath() D<hX%VJ%M  
{ TMGYNb%<bX  
return sFilePath; ihJ!]#Fbm  
} \gu8 ~zK  
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public void setSFilePath(String value) mGDy3R90  
{ 8.G<+
.  
sFilePath = value; R$!]z(  
} [+d~He  
4{Q$^wD+.  
W__Y^\~  
public String getSFileName() ?0'e_s  
{ *LMzq9n3o  
return sFileName; =0L%<@yA  
} `YUeVz>q?  
_&(L{cFx6  
b*W,8HF4,  
public void setSFileName(String value) 7;c^*"Ud  
{ d~MY z6"  
sFileName = value; |"PS e~ u  
} GSs?!BIC  
V?Q45t Ae  
4X",:B}  
public int getNSplitter() ,Ne9x\F  
{ (t){o>l  
return nSplitter; # >I_  
} :@@`N_2?  
=jKu=!QPq  
15VvZ![$V  
public void setNSplitter(int nCount) W\($LD"X  
{ Yecdw'BW?  
nSplitter = nCount; {sxdDl  
} )3A+Ell`  
} eIy:5/s  
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/* <& 3[|Ca  
**Utility.java [ #ih o(/  
*/ fN@ZJ~F%j  
package NetFox; P*i'uN  
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public class Utility { AFM+`{Cq  
-[J4nN&N  
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public Utility() </Y(4Xwf=  
{ #6 ni~d&0  
$IS!GS&:  
J5{  
} Wuo:PX'/9  
#'},/Lm@  
//线程睡眠 qO38vY){  
public static void sleep(int nSecond) lxCAZa\  
{ FaWDAL=Vhk  
try{
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Thread.sleep(nSecond); ;w+  
} +*xc4  
catch(Exception e) r`"T{o\e   
{ %sPze]  
e.printStackTrace (); wd32q7lGo1  
} j^;P=L0=  
} N@Oe[X8  
<7>1Z 82)  
//日志
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public static void log(String sMsg) vNs`UkA  
{ p;'.7_1  
System.err.println(sMsg); Kxa1F
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} }Xk_ xQVt{  
Sk"hqF.2  
~QlF(@ue  
public static void log(int sMsg) #AP;GoIf"j  
{ Z m%,L$F*L  
System.err.println(sMsg); $=,pQ q  
}
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} 7QnWw0  
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1=5HQ~|[TO  
/* Z9NN
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**TestMethod.java si)>:e  
*/ Nd"IW${Kg  
package NetFox; *!TQC6b$  
@%*2\8}C!  
!s^XWsb8  
public class TestMethod { z. X hE \  
M9o/6  
fzw:[z:%  
public TestMethod() X`EVjK  
{ ///xx/weblogic60b2_win.exe bM5V=b_H  
try{ k0N>J8y  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); po'b((q  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 1<Mb@t  
SiteFileFetch fileFetch = new SiteFileFetch(bean); < qab\M0W  
fileFetch.start(); ]P#W\LZp  
} :!Dm
,PP%  
catch(Exception e){e.printStackTrace ();} :*h1ik4t  
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} h,B4Tg'  
AG}j'   
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public static void main(String[] args) ,`Z4fz:  
{ gE$Uv*Gj  
new TestMethod(); rr2!H%:
 
} <`"  
} z/h]Jos  
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