http断点续传简单实现（java)

/* MLwh&I9)  
**SiteFileFetch.java Fy:CG6@X  
*/ |a9d]^  
package NetFox; QOXG:?v\  
import java.io.*; q?} /q  
import java.net.*; NG3!09eY  
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public class SiteFileFetch extends Thread { :[![9JS/  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 32h}+fd  
long[] nStartPos; //开始位置 l;{
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long[] nEndPos; //结束位置 %N5gQXg  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 :/YHU3~Y  
long nFileLength; //文件长度 @BQJKPF*  
boolean bFirst = true; //是否第一次取文件 x\(@v  
boolean bStop = false; //停止标志 4 mj\wBp  
File tmpFile; //文件下载的临时信息 >YG1sMV-J  
DataOutputStream output; //输出到文件的输出流 0u[Vd:()v(  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） &b :u~puM  
public SiteFileFetch(SiteInfoBean bean) throws IOException NGQBOV  
{ A|jmp~@K)+  
siteInfoBean = bean; P?|F+RoX$  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); hr@c7/L  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Zo$,{rl  
if(tmpFile.exists ()) ^`M,ju  
{ 2J?ON|2M  
bFirst = false; 9*s''=  
read_nPos(); u|]{|Ya'%  
} 6/{V#.(  
else FuqMT`  
{ {qxFRi#\k  
nStartPos = new long[bean.getNSplitter()]; ."`mh&+`  
nEndPos = new long[bean.getNSplitter()]; >]b>gc?3  
} sVXIR  
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} `FS)i7-o6  
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public void run() )?_x$GKY  
{ `D *U@iJ  
//获得文件长度 _8zZ.~)  
//分割文件 T}fH  
//实例FileSplitterFetch Nf@-i`  
//启动FileSplitterFetch线程 dKk\"6 o  
//等待子线程返回 *=G~26*!V  
try{ )|52B;yZx  
if(bFirst) GFA D  
{ YdgDMd-1  
nFileLength = getFileSize(); NT(gXEZ  
if(nFileLength == -1) S
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{ Ug}dw a  
System.err.println("File Length is not known!"); 5&Y%N(  
} D,$!.5OA  
else if(nFileLength == -2) j%w}hGW%,  
{ k@}?!V*l  
System.err.println("File is not access!"); Evjvaa^  
} 0EWov~Y?  
else AQ}(v,DOb  
{ lI,lR  
for(int i=0;i<nStartPos.length;i++) Q4~/Tl;  
{ [Eq7!_3  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); KImBQ2^Tu  
} NY(z
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for(int i=0;i<nEndPos.length-1;i++) HACY  
{ p*'%<3ml  
nEndPos = nStartPos[i+1]; 3bWYRW  
} 
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nEndPos[nEndPos.length-1] = nFileLength; /5**2Kgv1  
} DJWm7 t  
} yW=I*f  
! .q,m>?+  
wP|Amn+;  
//启动子线程 SRP.Mqg9  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; CIt%7 \c  
for(int i=0;i<nStartPos.length;i++) tVUC@M>'  
{ <bvbfS  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 4z;@1nN_8a  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), \zx &5a #  
nStartPos,nEndPos,i); {zckY  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 4J~ZZ  
fileSplitterFetch.start(); bUcEQGHcZ=  
} bU3P;a(  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), {4C/ZA{|l  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); crwui8  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", B,xohT  
nEndPos = " + nFileLength); \Fh#CI  
// fileSplitterFetch[nPos.length-1].start(); bmid;X|  
q.}M^iDe  
+VSq[P  
//等待子线程结束 jV|j]m&t  
//int count = 0; ~10>mg  
//是否结束while循环 s^&Oh*SP*  
boolean breakWhile = false; =/#+,  
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while(!bStop) :cE6-Fv  
{ 6x.ZS'y  
write_nPos(); e=H,|)P  
Utility.sleep(500); 8h?):e  
breakWhile = true; NMy+=GZu^  
-%G}T}"_  
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for(int i=0;i<nStartPos.length;i++) If*+yr|  
{ }G/#Nb)  
if(!fileSplitterFetch.bDownOver) )%zOq:{\5  
{ 7Rq|N$y.3  
breakWhile = false; n5NwiSE  
break; sC}p_'L  
} 15l{gbCW  
} IG(1h+5R(  
if(breakWhile) %U uVD  
break; dSP~R  
W2`/z)[*>  
\/8oua_)  
//count++; m~f J_  
//if(count>4) .7K<9K+P  
// siteStop(); L,/(^0;  
} Ovhd%qV;Y  
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System.err.println("文件下载结束！"); l~C=yP(~  
} w=Yc(Y:h  
catch(Exception e){e.printStackTrace ();} K2o\+t  
} US'rhSV  
Chs#}=gzi  
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//获得文件长度 n5U-D0/Q  
public long getFileSize() !7>~=n_,L.  
{ 0|chRX  
int nFileLength = -1; }od5kK;  
try{ EpCT !e  
URL url = new URL(siteInfoBean.getSSiteURL());  %>z)Q  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); lh]Q\  
httpConnection.setRequestProperty("User-Agent","NetFox"); -tH^Deo  
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int responseCode=httpConnection.getResponseCode(); +FBUB  
if(responseCode>=400) "q]r{0  
{ 
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processErrorCode(responseCode); h?-*SLT  
return -2; //-2 represent access is error P 5_l&  
} ;!9-I%e  
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 N3m~nEj  
String sHeader; it)!-[:bm  
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for(int i=1;;i++) Z1Pdnc7S[  
{ *p.70,5,  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); mM;5UPbZ  
//Utility.log(in.readLine()); sKniqWi  
sHeader=httpConnection.getHeaderFieldKey(i); r"hogmFD;  
if(sHeader!=null) }{SpV  
{ ]m=2 $mK  
if(sHeader.equals("Content-Length")) q_b,3Tp  
{ YsA.,  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); G9AQIU%ii  
break; M@a=|N~  
} 6!A+$"  
} -oMp@2\e  
else
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break; gCP f1z  
} g&?RQ  
} "V>p  
catch(IOException e){e.printStackTrace ();} C#oH7o+_.  
catch(Exception e){e.printStackTrace ();} [eLU}4v{  
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Utility.log(nFileLength); >mCS`D8  
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return nFileLength; "bmWr)  
} /DE`>eJY  
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//保存下载信息（文件指针位置） H6V!W\:s  
private void write_nPos() +A
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{ PCX X[N  
try{ h7 c  
output = new DataOutputStream(new FileOutputStream(tmpFile)); $/|2d4O:{  
output.writeInt(nStartPos.length); >`)IdX  
for(int i=0;i<nStartPos.length;i++) 9 lH00n+'  
{ TYu(;~  
// output.writeLong(nPos); Q$:>yveR*  
output.writeLong(fileSplitterFetch.nStartPos); lEr_4!h$rZ  
output.writeLong(fileSplitterFetch.nEndPos); jr3FDd]  
} b75en{aDi*  
output.close(); ?5Q_G1H&  
} Br}0dha3E  
catch(IOException e){e.printStackTrace ();} Y
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catch(Exception e){e.printStackTrace ();} .]y"04@]  
} )o N#%%SB<  
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//读取保存的下载信息（文件指针位置） v?<Tkw ^F  
private void read_nPos() "3e1 7dsY  
{ *<#$B}!{  
try{ IRY/0v  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile));  .H7xG'$  
int nCount = input.readInt(); F&)(G\  
nStartPos = new long[nCount]; P+(q38f[  
nEndPos = new long[nCount]; jImw_Q  
for(int i=0;i<nStartPos.length;i++) up )JU [  
{ @3W
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nStartPos = input.readLong(); pUm|e5  
nEndPos = input.readLong(); 5K[MKfT  
} 1Farix1YDq  
input.close(); 5o2vj8::  
} hw)#TEt   
catch(IOException e){e.printStackTrace ();} 'E_~>  
catch(Exception e){e.printStackTrace ();} WP ~]pduT  
} _2wH4^Vb  
vf/|b6'y  
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private void processErrorCode(int nErrorCode) mY0FewwTy  
{ bX'.hHR  
System.err.println("Error Code : " + nErrorCode); "[Hn G(gA  
} |L%d^m  
z3C@0v=u>  
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//停止文件下载 SE0&CV4  
public void siteStop() ]h4r@L3  
{ V4tObZP3Ff  
bStop = true; AB[#
  
for(int i=0;i<nStartPos.length;i++) K/IG6s;Xj  
fileSplitterFetch.splitterStop();  zPW_  
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} g;._Q  
} 6sz:rv}  
//负责部分文件的抓取 c]>LL(R-7)  
**FileSplitterFetch.java #8sv*8&  
*/ zTb,h  
package NetFox; Qzq3{%^x_  
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import java.io.*;  mm9xO%  
import java.net.*; L/7YI\C2  
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public class FileSplitterFetch extends Thread { #@8JYzMq%  
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String sURL; //File URL 0o_wy1O1,  
long nStartPos; //File Snippet Start Position -_+,HyJP  
long nEndPos; //File Snippet End Position
>Q% FW  
int nThreadID; //Thread's ID v|@1W Uc,g  
boolean bDownOver = false; //Downing is over N5jJ,iz  
boolean bStop = false; //Stop identical tVqc!][  
FileAccessI fileAccessI = null; //File Access interface m$WN"kV`,9  
U?&&yynK  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException (hn;C>B  
{ PCZ%<>v  
this.sURL = sURL; i[40p!~  
this.nStartPos = nStart; *G(ZRj@33  
this.nEndPos = nEnd; T)tf!v3v  
nThreadID = id; K</="3 HK  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 b|E1>TkY  
} *7
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-I*NS6  
%h"%G=:  
public void run() Y2>0Y3yM  
{ .XPPd?R  
while(nStartPos < nEndPos && !bStop) c(r8 F[4w  
{ eiwPp9[0
8  
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) ={ H  
try{
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URL url = new URL(sURL); X\HP&;Wd  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); M.0N`NmS  
httpConnection.setRequestProperty("User-Agent","NetFox"); SPo}!&p$~  
String sProperty = "bytes="+nStartPos+"-"; 87q~ nk  
httpConnection.setRequestProperty("RANGE",sProperty); bC0DzBnM;  
Utility.log(sProperty); <0!)}O  
,;~@t:!c  
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InputStream input = httpConnection.getInputStream(); jrZH1dvE  
//logResponseHead(httpConnection); +hUz/G+3  
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byte[] b = new byte[1024]; WNWtQ2]  
int nRead; BX-fV|  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) >%i]p  
{ |tdsg  
nStartPos += fileAccessI.write(b,0,nRead); =At)
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//if(nThreadID == 1) "
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// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); .qD=u1{p9  
} E0aJ~A(Hv  
v%!'vhf_K  

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Utility.log("Thread " + nThreadID + " is over!"); #!R=h|  
bDownOver = true; 3iBUIv  
//nPos = fileAccessI.write (b,0,nRead); 7]lUPLsl  
} *!&,)
''  
catch(Exception e){e.printStackTrace ();} J[jzkzSu`  
} `|f1^C^  
} $.T\dm
-  
}CB9H$FkCY  
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//打印回应的头信息 j5V{,lf  
public void logResponseHead(HttpURLConnection con) WdJJt2'  
{ r>Cv@4/j  
for(int i=1;;i++) . E?a  
{ Fd1jElt  
String header=con.getHeaderFieldKey(i); L]#b=Y  
if(header!=null) <z R CT  
//responseHeaders.put(header,httpConnection.getHeaderField(header));  #[yZP9  
Utility.log(header+" : "+con.getHeaderField(header)); =L&dV]'4P  
else 9 gWqs'  
break; 5[|ZceY  
} 'NSfGC%7R  
} &9Xn:<"`)  
t2RL|$>F1  
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public void splitterStop() ~Zo;LSI  
{ @JU Xp  
bStop = true; prO
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} rhj_cw  
#?klVK&e/  
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} H.#zbKj  
!A'3Mw\Nm  
f=T&$tZ<  
/* NEff`mwm5)  
**FileAccess.java X^7n/|%*.  
*//文件访问(定位，写) 3eR c>^wh  
package NetFox; 0^mCj<g  
import java.io.*; B(,j*,f  
`tH:oP0=  
MD>xRs   
public class FileAccessI implements Serializable{ OXD*ZKi8  
BT*{&'\/  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 VJOB+CKE  
RandomAccessFile oSavedFile; Y20T$5{#  
long nPos; ]qO*(m:}o  
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t 4>\;  
public FileAccessI() throws IOException %eW2w@8]  
{  LXf*  
this("",0); ~w"e 2a  
} +r$M 9  
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mV#U=zqb!S  
public FileAccessI(String sName,long nPos) throws IOException
\VHRI<$+5  
{ 7[It  
oSavedFile = new RandomAccessFile(sName,"rw");  .F/
0:)  
this.nPos = nPos; A&L2&ofV&q  
oSavedFile.seek(nPos); Wh^wKF~%  
} X{tfF!+iy  
rL|9Xru  
.9@y*_9  
public synchronized int write(byte[] b,int nStart,int nLen) g![?P"i^t  
{ &Rt^G  
int n = -1; 'W*ODAz6  
try{ ~As_O6JI  
oSavedFile.write(b,nStart,nLen); ,QPo%{:p  
n = nLen;
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} n |Q'>  
catch(IOException e) }$@EpM  
{ i9v|*ZM"  
e.printStackTrace (); _l=X?/
 
} "J>8ZUP  
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return n; yt#~n_  
} 2!?=I'uMA  
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} C(&3L[  
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,
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/* #r'S@:[  
**SiteInfoBean.java 2k+u_tj>  
*/ )uC5  
package NetFox; r
nRWL4  
y;=/S?L
.:  
"GB493=v  
public class SiteInfoBean { U[|o!2$  
8XD_p);Oy  
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private String sSiteURL; //Site's URL N7-LgP  
private String sFilePath; //Saved File's Path S#N4!"  
private String sFileName; //Saved File's Name PZk"!I<oN  
private int nSplitter; //Count of Splited Downloading File C~R,,  
cHX~-:KOr  
0`Y"xN`'i  
public SiteInfoBean() @o>3 Bv.  
{//nSplitter的缺省值为5 #PQhgli  
//default value of nSplitter is 5 2-beq<I  
this("","","",5);
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} zszx~LSvIT  
h~s h!W8  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) :Hj #1-U  
{ QSyPtjg]  
sSiteURL= sURL; +
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sFilePath = sPath; PH>`//D%n?  
sFileName = sName; Qq3UC%Z1  
this.nSplitter = nSpiltter; I
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{QVs[ J1  
 >f*Zf(F  
} gXe`G(w  
ZiC~8p
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tC\(H=ecP  
public String getSSiteURL() !YIW8SP)  
{ H0-v^H>^  
return sSiteURL; La r9}nx0  
} 4nKlW_{,  
o "1X8v  
WT jy"p*  
public void setSSiteURL(String value) g[(Eh?]Sc  
{ *Qy,?2  
sSiteURL = value; aRcVoOq  
} 0gH;y+\=*  
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Y?\PU{O  
public String getSFilePath() DhN<e7c`  
{ *H~&hs>k  
return sFilePath; 3M5wF6nY[[  
}  I}u&iV`  
qkBCI,X_Y  
GuKiNYI_  
public void setSFilePath(String value) `NCH^)  
{ J }|6m9k!  
sFilePath = value; i=jYl  
} @.} @K  
m.Ki4NUm  
lQ#='Jqfp  
public String getSFileName() Zty9O8g  
{ 23/;W|   
return sFileName; naVbcY  
} v$#l]A_D  
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public void setSFileName(String value) i!yE#z
ew  
{ G$VE o8Blb  
sFileName = value; 8dwKJ3*.  
} 6Cgc-KNbk  
.q|k459oi  
 NR98]X  
public int getNSplitter() :H>0/^Mg0  
{ w+iIay  
return nSplitter; a;=IOQ  
}  bU$M)  
gjn1ha"h%.  
^J)0i_RS  
public void setNSplitter(int nCount) "x O+  
{ GrI<w.9X  
nSplitter = nCount; wicW9^ik  
} dZCnQIS  
} v(=E R%  

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/* 7KN+ @6!x  
**Utility.java mX[J15  
*/ {_UOS8j7  
package NetFox; GQDW}b8  
A+hA'0isF@  
;Q0H7)t:  
public class Utility { 5em*9Ko  
j7~Rw"(XQc  
e?+&2zMq  
public Utility() 5 Q/yPQN  
{ %Ot*k%F  
}J $\<ZT  
BT"n;L?[  
} ]Rj?OSok  
\k5 sdHmI[  
//线程睡眠 h}Lrpr2r  
public static void sleep(int nSecond) GK1oS  
{ 395`Wkv  
try{ Q096M 0m  
Thread.sleep(nSecond); y7x*:xR[  
} 6N[X:F 3`,  
catch(Exception e) \|
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{ h)Ol1[y`  
e.printStackTrace (); zBc |
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} !o\e/HGc!  
} W0<2*7s  
 vURgR  
//日志 Xn02p,,  
public static void log(String sMsg) pO)5NbU  
{ 9ePom'1f1  
System.err.println(sMsg); 77-G*PI*I  
} p$mt&,p  
KPA.5,ai  
N
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public static void log(int sMsg) qWD(rq+9  
{ O bc>f|l]  
System.err.println(sMsg); Z=oGyA  
} 0+/ew8~$  
} I.it4~]H  
1rON8=E  
rTqGtmulG  
/* z fu)X!t^  
**TestMethod.java U:bnX51D4  
*/ )FN$Jlo  
package NetFox; E6zPN?\ <  

F>eo.|'  
9 dK`  
public class TestMethod { !C ZFbz~:  
}=|plz}  
Ey%KbvNv  
public TestMethod() gux?P2f  
{ ///xx/weblogic60b2_win.exe Re*_Dt=r  
try{ u:H:N]  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); e xkPu-[W  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); h4Xz"i{z  
SiteFileFetch fileFetch = new SiteFileFetch(bean); PJ\k|
 
fileFetch.start(); *,28@_EwY  
} 6Ad=#MM  
catch(Exception e){e.printStackTrace ();} L%+mD$@u  
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$laUkD#vz  
} ;vy<!@Y;8  
J,\e@  
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public static void main(String[] args) je%D&ci$  
{ b@O{eQB  
new TestMethod(); H4$f+  
} NryOdt tI  
} jB`:(5%RO  
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