http断点续传简单实现（java)

/* >[fu&r1  
**SiteFileFetch.java y?<KN0j  
*/ P]43FPb  
package NetFox; l;lrf3  
import java.io.*; N*o{BboK;  
import java.net.*; !!y]pMjJa@  
o.{W_k/n  
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public class SiteFileFetch extends Thread { %f;dn<m=c  
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SiteInfoBean siteInfoBean = null; //文件信息Bean }KI/fh  
long[] nStartPos; //开始位置 0[MYQl`  
long[] nEndPos; //结束位置 <\^0!v  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 vYed_'_  
long nFileLength; //文件长度 C^J<qq&  
boolean bFirst = true; //是否第一次取文件 tVAi0`DV  
boolean bStop = false; //停止标志 9TW[;P2> )  
File tmpFile; //文件下载的临时信息 :ky`)F`  
DataOutputStream output; //输出到文件的输出流 %QezC+n  
q[&Kr+)j  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） +>Wo:kp3  
public SiteFileFetch(SiteInfoBean bean) throws IOException &k:xr,N=  
{ kxMvOB$  
siteInfoBean = bean; 4q}+8F`0F  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); -S'KxC  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); xXe3E&  
if(tmpFile.exists ()) 5\+*ml  
{ im<bo Mv  
bFirst = false; 4t, 2H"M  
read_nPos(); 7>N~l  
} PCviQ!X  
else !HY^QK  
{ K./qu^+k  
nStartPos = new long[bean.getNSplitter()]; yw^P
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nEndPos = new long[bean.getNSplitter()]; #Rw!a#CX.  
} 'nCVjO7o  
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}`uyOgGg*  
} F.[%0b E  
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public void run() )w7vE\n3  
{ L'+bVP{L  
//获得文件长度 Y%KowgP\  
//分割文件 4ag
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//实例FileSplitterFetch +_5*4>MC  
//启动FileSplitterFetch线程 6jq*lnA%  
//等待子线程返回 zp}7p~#k^  
try{ }z`x-(V  
if(bFirst) $qNF /rF  
{ 2js/>L0  
nFileLength = getFileSize(); dbf<k%i6  
if(nFileLength == -1) <ToS&  
{ =pL$*`]?  
System.err.println("File Length is not known!"); M':-f3aT%  
} @%4'2b  
else if(nFileLength == -2) q/s-".%P  
{ m?e/MQr  
System.err.println("File is not access!"); >Pw5!i\  
} )D8op;Fn  
else K9N31'  
{ lC5zqyG  
for(int i=0;i<nStartPos.length;i++) ,6^<Vg  
{ @Jd&[T27Lr  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 9UM)"I&k  
} u?,>yf.;s  
for(int i=0;i<nEndPos.length-1;i++) }B0[S_mw  
{ }&0LoW/  
nEndPos = nStartPos[i+1]; >|3Y+X  
} ZF7n]LgSc&  
nEndPos[nEndPos.length-1] = nFileLength; @76}d  
} nCYz];".  
} KI9Pw]]{-  
w%L4O;E]*{  
z^9oaoTl  
//启动子线程 [UwQi!^-O  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; f ,e]jw@  
for(int i=0;i<nStartPos.length;i++) =%U&$d|@G  
{ @X/ 1`Mp  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), @b(@`yz.a  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), AXbb-GK  
nStartPos,nEndPos,i); ^Gk)aX  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); pA8bFtt  
fileSplitterFetch.start(); e66Ag}Sw|  
} h1~h&F?  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), %pVsafV  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); #$UwJB]_D  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", k]ZE j/y~  
nEndPos = " + nFileLength); z</C)ObL  
// fileSplitterFetch[nPos.length-1].start(); -nGcm"'6F  
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2/3yW.C  
//等待子线程结束 V7WL Gy.,  
//int count = 0; >lIzeEW#  
//是否结束while循环 +.Vh<:?
 
boolean breakWhile = false; _i>_Sn1"  
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3$"V,_TBZ  
while(!bStop) +pYgh8w@  
{ U*+-#  
write_nPos(); k (AE%eA  
Utility.sleep(500); d'(n/9K  
breakWhile = true; hTa X@=Ra  
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< }K9 50  
for(int i=0;i<nStartPos.length;i++) @vq)Y
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{ kk5&lak2V  
if(!fileSplitterFetch.bDownOver) T"99m^y  
{ 4- QlIIf  
breakWhile = false; |ufT)+:  
break; #_^p~:  
} ~AD>@;8fG  
} 0WzoI2Q  
if(breakWhile) r.)n
>  
break; od#L
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AyQ5jkIE^{  
//count++; bbq`gEV  
//if(count>4) ^0"^  
// siteStop(); oaha5aWH  
} [? "hmSJ  
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System.err.println("文件下载结束！"); 41/civX>V  
} (~Bm\Jn  
catch(Exception e){e.printStackTrace ();} @|;[ ;:h@  
} ^5MM<73  
()j)}F#Z`  
N@_y<7#C  
//获得文件长度 FS8l}t  
public long getFileSize() Ng<ic  
{ G8]{pbX  
int nFileLength = -1; 8oUR/___  
try{ B (eXWWT_  
URL url = new URL(siteInfoBean.getSSiteURL()); SeZ+&d  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); fFVQu\  
httpConnection.setRequestProperty("User-Agent","NetFox"); %{
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int responseCode=httpConnection.getResponseCode(); A'![*O  
if(responseCode>=400) ?lqqu#;8  
{ Nq9pory^  
processErrorCode(responseCode); ^xk
4HF   
return -2; //-2 represent access is error $Vp&7OC]  
} c>
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String sHeader; rp @%0/[  
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for(int i=1;;i++) P{s1NorKDh  
{ Yrf?|,  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ^4JK4+!Zfq  
//Utility.log(in.readLine()); r#j3O}(n  
sHeader=httpConnection.getHeaderFieldKey(i); ,]qc#KDq-1  
if(sHeader!=null) >yenuqIKQv  
{ #WUN=u  
if(sHeader.equals("Content-Length")) ]ml'd  
{ UC`sq-n  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ZQR)k:k7  
break; J#w=Z>oz<  
} %26HB w=JF  
} <Qbqxw  
else 7!o
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break; \2f?)id~  
} W }Ll)7(|T  
} CyVi{"aF3  
catch(IOException e){e.printStackTrace ();} _MQh<,Z8  
catch(Exception e){e.printStackTrace ();} m-[xrVV  
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Utility.log(nFileLength); Z@JTZMN_  
/a$Zzs&xs  
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return nFileLength; 55y}t%5  
} D!)h92CIDm  
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//保存下载信息（文件指针位置） X)TZ S  
private void write_nPos() +5GC?cW  
{ PJKxh%J  
try{ kDiR2K&  
output = new DataOutputStream(new FileOutputStream(tmpFile)); qIy9{LF  
output.writeInt(nStartPos.length); w(Mi?  
for(int i=0;i<nStartPos.length;i++) kmJ<AnK  
{ d.>O`.Mu)}  
// output.writeLong(nPos); ]3U|K .G  
output.writeLong(fileSplitterFetch.nStartPos); ]'#^ ~.  
output.writeLong(fileSplitterFetch.nEndPos); tQ
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} '7]9q#{su  
output.close(); T
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} 3=Xvl 58k  
catch(IOException e){e.printStackTrace ();} ?a?] LIE8  
catch(Exception e){e.printStackTrace ();} !$-QWKD4  
} ccW{88II7w  
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//读取保存的下载信息（文件指针位置） Pj^Ccd'>=  
private void read_nPos() ,+5!1>\  
{ AUU(fy#<  
try{ 1ww~!R  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ?I.bC   
int nCount = input.readInt(); M%eTNsbNm  
nStartPos = new long[nCount]; :r_/mzR#  
nEndPos = new long[nCount]; 5e'**tbKH  
for(int i=0;i<nStartPos.length;i++) rqM_#[Y?  
{ $yZP"AsAR  
nStartPos = input.readLong(); y$|OE%S  
nEndPos = input.readLong(); #/K71Y  
} {*Qx^e`h$.  
input.close(); cn ;2&  
} $O9#4A;  
catch(IOException e){e.printStackTrace ();} 1Dm$:),^T}  
catch(Exception e){e.printStackTrace ();} N1]P3  
} `b5pa`\4  
*_uGzGB&G  
04E#d.o'  
private void processErrorCode(int nErrorCode) -fx$)d~  
{ 2CPh'7|l  
System.err.println("Error Code : " + nErrorCode); `[4{]jX+<  
} 4Cf.%f9@  
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mLeK7?GL  
//停止文件下载 u,Cf4H*xS  
public void siteStop() X gA( D  
{ xNxSgvco,  
bStop = true; kAk+Sq^n  
for(int i=0;i<nStartPos.length;i++) #Bas+8 @,  
fileSplitterFetch.splitterStop(); AhSN'gWpbF  
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} 3gba~}c)  
} $)M5@KT  
//负责部分文件的抓取 ]AB4w+6!  
**FileSplitterFetch.java Md1ePp]  
*/ nTPq|=C  
package NetFox; T [2l32  
,9~2#[|lq  
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import java.io.*; .0
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import java.net.*; r/mKuGa]  
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public class FileSplitterFetch extends Thread { 2umgF  
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String sURL; //File URL }:hN}*H  
long nStartPos; //File Snippet Start Position TK
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long nEndPos; //File Snippet End Position ?=0BU}  
int nThreadID; //Thread's ID 5Z*6,P0  
boolean bDownOver = false; //Downing is over }w/6"MJ[n  
boolean bStop = false; //Stop identical ,ftKRq  
FileAccessI fileAccessI = null; //File Access interface 78/,rp#'_  
!juh}q&}|  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException aLt2fB1)  
{ xy[aZr  
this.sURL = sURL; QNm8`1  
this.nStartPos = nStart; x3Ze\N8w  
this.nEndPos = nEnd; 4
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nThreadID = id; <#F@OU  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Q?]-/v  
} 6_kv~`"tZ  
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![j?/376  
public void run() M.?[Xpa  
{ rki0!P`  
while(nStartPos < nEndPos && !bStop) o3=pxU*  
{ JBt2R=  
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try{ 9vI<\ Xa  
URL url = new URL(sURL); 25{-GaB
 
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 4Be'w`Q {  
httpConnection.setRequestProperty("User-Agent","NetFox"); l~Rd\.O  
String sProperty = "bytes="+nStartPos+"-"; v,^W& W.  
httpConnection.setRequestProperty("RANGE",sProperty); 7oV$TAAf  
Utility.log(sProperty); ;9$71E  
" `FcW  
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InputStream input = httpConnection.getInputStream(); <sli!r
v  
//logResponseHead(httpConnection); \45F;f_r6  
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6W[~@~D=  
byte[] b = new byte[1024]; '8w>=9Xl  
int nRead; cp$GP*{@  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) yc+pNC)ue_  
{ ohna1a^  
nStartPos += fileAccessI.write(b,0,nRead); j9xu21'
!%  
//if(nThreadID == 1) v6P2v  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 2"6bz^>}  
} @L$!hT
aP  
d$hBgJe>N  
-}(2}~{e(  
Utility.log("Thread " + nThreadID + " is over!"); fPPC`d&Q3  
bDownOver = true; z3I |jy1  
//nPos = fileAccessI.write (b,0,nRead); %'OY  
} Kf
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catch(Exception e){e.printStackTrace ();} ,pIh.sk7s*  
} D$N;Qb  
} +/ rt'0o  
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-}3nIk<N  
//打印回应的头信息 F3[,6%4v  
public void logResponseHead(HttpURLConnection con) Wh)!Ha}  
{ h0$Y;=YA  
for(int i=1;;i++) p(6 sN=  
{ T@A Qe[U'v  
String header=con.getHeaderFieldKey(i); ;5DDV6  
if(header!=null) Y (pUd3y  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); y
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Utility.log(header+" : "+con.getHeaderField(header)); %=!] 1  
else Dxy^r*B  
break; X
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} 2VzYP~Jg  
} F1A40h7R$Y  
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PV:J>!]  
public void splitterStop() 5owK2  
{ jD${ZIv  
bStop = true; xHMFYt+0$G  
} L7hRFf-o  
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} j+@3.^vK
 
. P+Qu   
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/* @$~IPg[J  
**FileAccess.java BM'!odR
v  
*//文件访问(定位，写) K{{_qFj@<y  
package NetFox; *~>p;*  
import java.io.*; GbclR:G  
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- Z`RKR8C  
public class FileAccessI implements Serializable{ /-,\$@J
5)  
/0 4US5En  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 > (9\ cF{  
RandomAccessFile oSavedFile; eIfQ TV  
long nPos; -rn6ZSD)  
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public FileAccessI() throws IOException &iVdqr1,  
{ vj]>X4'i  
this("",0); ,|B-Nq  
} "X8jpg  
V*{rHp{=p  
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public FileAccessI(String sName,long nPos) throws IOException 7oWMjw\  
{ mr^3Y8$s  
oSavedFile = new RandomAccessFile(sName,"rw"); c#s
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this.nPos = nPos; qS2Nk.e]o  
oSavedFile.seek(nPos); "GZieI D  
} :#pdyJQ_  
m$kQbPlatN  
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public synchronized int write(byte[] b,int nStart,int nLen) b1KtSRLV  
{ 0n}13u=}  
int n = -1; RHg-Cg`  
try{ jk
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oSavedFile.write(b,nStart,nLen); E5d$n*A  
n = nLen; odsFgh  
} 0(D^NtB7  
catch(IOException e) fq]PKLW'  
{ pW(rNAJ!  
e.printStackTrace (); Ki2!sADd  
} by X!,  
ds(?:zx#  
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return n; N8b\OTk2  
} "y,YC M`  
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} ~ELMLwn.  
/|1p7{km  
//U1mDFT  
/* l%0bF9\  
**SiteInfoBean.java 4VWk/HK-!  
*/ 6lSz/V;  
package NetFox; <+i(CGw  
zTF{ g+  
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public class SiteInfoBean { !Rn6x $_  
_rT\?//B  
9=%zdz2_S  
private String sSiteURL; //Site's URL nqcq3o*B  
private String sFilePath; //Saved File's Path Ke\\B o,  
private String sFileName; //Saved File's Name (^d7K:-'  
private int nSplitter; //Count of Splited Downloading File QJGGce  
lLx!_h  
>='/%Ad  
public SiteInfoBean() `@~e<s`j  
{//nSplitter的缺省值为5 P[nc8z[   
//default value of nSplitter is 5 XA>W>|  
this("","","",5); 5p;AON  
} 94u{k1d x  
Ps!MpdcL3  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) XO <wK  
{ OXEk{#Uf[3  
sSiteURL= sURL; ,N.8  
sFilePath = sPath; : \+xXb{  
sFileName = sName; N:1aDr;  
this.nSplitter = nSpiltter; 8\n3 i"  
d7OygDb<  
U v2.Jo/Q  
} @I_cwUO  
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8+zW:0"[  
public String getSSiteURL() "TV'}HH  
{ 6j
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return sSiteURL; :QE5 7.  
} Dp@XAyiA[  
TR"C<&y$j  
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public void setSSiteURL(String value) @IT[-d  
{ g9_zkGc7  
sSiteURL = value; {keZ_2  
} /sE,2X*BT  
Z*,e<zNQ  
~6[?=mOi'  
public String getSFilePath() h [TwaR  
{ Wh[QR-7Ew  
return sFilePath;
YB#fAU  
} JzyCeM
=  
fqNh\~kja  
%()d$.F  
public void setSFilePath(String value) X8Z?G,[H  
{ %pC<T*f  
sFilePath = value; eV;r /4  
} A2_ut6&eb  
=u.@W98, K  
Ox3=1M0  
public String getSFileName() H4$qM_N  
{ L*@`i ]jl  
return sFileName; 5{c;I<0  
} b?H"/Mu.  
Y]z :^D  
T(J'p4  
public void setSFileName(String value) 
j\2Qe%d  
{ ClG%zE&i  
sFileName = value; 6g(;2gY  
} c[dSO(=  
Y },E3<  
!_QI<=X  
public int getNSplitter() q_MN  
{ TI>5g(:3\  
return nSplitter; ,jU>V]YC  
} yD\q4G  
^q7V%{54  
TxrW69FV7  
public void setNSplitter(int nCount) lriezI  
{ ^y<^hKjV  
nSplitter = nCount; )aS:h}zn  
} g~lv/.CnA+  
} ^e:z ul{;]  
bnxp[Qk|5  
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/* sh/,"b2!P  
**Utility.java P,v7twc0M  
*/ L+t / E`  
package NetFox; #S>N}<>  
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public class Utility { LjKxznn o  
Z{8%Cln  
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public Utility() cVi_#9u"  
{ Agcss20
.  
Bm~^d7;Cw  
1+%UZK= K  
} Kz'GAm\  
pa-*&p  
//线程睡眠 \f,<\mJ#  
public static void sleep(int nSecond) pY&6p~\p  
{ ib,`0=0= O  
try{ 757&bH|a  
Thread.sleep(nSecond); s_^`t+5  
} #X(2  
catch(Exception e) <IrhR,@M,L  
{ bTs2$81[  
e.printStackTrace (); N"9^A^w8k  
} ; _%zf5;'  
} T;u
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`E~"T0RX  
//日志 EU(e5vO  
public static void log(String sMsg) %!` %21  
{ "
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System.err.println(sMsg); XX=OyDLqP  
} O>E}Lu;|  
FH</[7f;@N  
2j f!o  
public static void log(int sMsg) uc9h}QJ*  
{ gs<~)&x  
System.err.println(sMsg); y[J9"k(@  
} R3g)LnN  
} 4m~y%> &  
S{llpp{E  
% jDH{xSMb  
/* F`KXG$  
**TestMethod.java `yR/M"u6T  
*/ >4g!ic~O  
package NetFox; x
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TY/'E#.  
public class TestMethod { hq"nRH  
5$ How!  
LYAG
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public TestMethod() 2fdN@iruB  
{ ///xx/weblogic60b2_win.exe Zl[EpXlZ  
try{ aj|3(2;Kp  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); P%B|HnG^  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ,`U>BBBLv  
SiteFileFetch fileFetch = new SiteFileFetch(bean); z<Z0/a2'1  
fileFetch.start(); ]prw=rD  
} ?121 as}z  
catch(Exception e){e.printStackTrace ();} -8)C6"V{  
8K^#$,.."  
AK lra$  
} G%Lt>5*!nE  
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public static void main(String[] args) {pQ8/Af!  
{ uv5NqL&  
new TestMethod(); NXLb'm
H~  
} <|'ETqP<+  
} Sj)?!  
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