http断点续传简单实现（java)

/* Cdz&'en^  
**SiteFileFetch.java 0!\C@wnH  
*/ 2`$*HPj+G  
package NetFox; gT+g@\u[
  
import java.io.*; a|7C6#iz$  
import java.net.*; /:4J  
@.eN+o9|  
@ep.wW  
public class SiteFileFetch extends Thread { N>H@vt~  
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SiteInfoBean siteInfoBean = null; //文件信息Bean =6[.||9  
long[] nStartPos; //开始位置 u?Ffqt9'  
long[] nEndPos; //结束位置 ?s^qWA  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 )j36Y =r3  
long nFileLength; //文件长度 ,<
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boolean bFirst = true; //是否第一次取文件 h+Co:pr  
boolean bStop = false; //停止标志 */;7Uv7  
File tmpFile; //文件下载的临时信息 ,TQec:B  
DataOutputStream output; //输出到文件的输出流 IgX &aW
 
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） jq,M1  
public SiteFileFetch(SiteInfoBean bean) throws IOException &jF'2D^_  
{ *-nO,K>y`  
siteInfoBean = bean; Te+(7 Z  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); *4U_MM#rX  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); gZ,h95
'  
if(tmpFile.exists ()) odhS0+d^  
{ g-sNYd%?a  
bFirst = false; /4an@5.\C  
read_nPos(); p3=Py7iz  
} m)tu~neM  
else JQ1MuE'  
{ Ss>pNH@c  
nStartPos = new long[bean.getNSplitter()]; |U|>YA1[b  
nEndPos = new long[bean.getNSplitter()]; J\@6YU[A  
} R.^]{5  
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} RpivO,   
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public void run() {rKC4:  
{ h3
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//获得文件长度 SOOVUMj  
//分割文件 u<edO+  
//实例FileSplitterFetch WO qDW~  
//启动FileSplitterFetch线程 a2Ak?W1  
//等待子线程返回 -l= 4{^pK  
try{ w|9 >4  
if(bFirst) "2cOSPpQL  
{ 8fXiadP#  
nFileLength = getFileSize(); !Y~UO)u2  
if(nFileLength == -1) Y2r}W3F=  
{ Q@W/~~N  
System.err.println("File Length is not known!"); cRT'?w`}  
} 9
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else if(nFileLength == -2) ?\V#^q-  
{ B6 0  
System.err.println("File is not access!"); e(0OZ_w  
} Ehx9-*]
 
else Tv=lr6t8  
{ (7Z+De?  
for(int i=0;i<nStartPos.length;i++) `8!9Fp  
{ h=#w< @  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); `B)@  
} _,J+b R+b  
for(int i=0;i<nEndPos.length-1;i++) |MwV4^  
{ I1<WHq  
nEndPos = nStartPos[i+1]; 6'#5Dqw"r  
} TjUwe@&Rw  
nEndPos[nEndPos.length-1] = nFileLength; .?:*0
 
} lFzVd N  
} =1IK"BA2?  
ok:uTeJI  
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//启动子线程 uM2@&)u  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; AF'<  
for(int i=0;i<nStartPos.length;i++) %(YQ)=w  
{ `Lr], >aG  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), /|?$C7%a\D  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), h&0zR#t  
nStartPos,nEndPos,i); cC/h7odY  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); PgkU~68`  
fileSplitterFetch.start(); |+nmOi,z  
} \&Yn)|!  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), eAy,T<#  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); .&^
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// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 6w^P{%ul  
nEndPos = " + nFileLength); (/]'e}  
// fileSplitterFetch[nPos.length-1].start(); Z8SwW<{ $  
 2v{WX  
FLi'}C  
//等待子线程结束 6<lo0PQ"Z  
//int count = 0; x92^0cMf  
//是否结束while循环 y]h0c<NP  
boolean breakWhile = false; !..<_qfw  
:K| H/kht  
'PF>#
X''  
while(!bStop) 5u!\c(TJ+  
{ eEZgG=s  
write_nPos(); f$lb
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Utility.sleep(500); 0S{23L4C  
breakWhile = true; -|.NwGh  
8 .%0JJ.3  
)3h\QE!z  
for(int i=0;i<nStartPos.length;i++) sYKx3[V/  
{ AQ,lLn+  
if(!fileSplitterFetch.bDownOver) ;(i6 X)  
{ +mo
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breakWhile = false; (nqry[g&  
break; *ID=X!v  
} 94tfR$W;-  
} kdNo<x1o  
if(breakWhile) FGV L[\  
break; a"jE\OZ{+s  
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j9 nw,x
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//count++; <%)vl P#@  
//if(count>4) L
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// siteStop(); `5Y*) q  
} f?5>V   
/QXUD.( 8  
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System.err.println("文件下载结束！"); z CLaHx!  
}  t`o"K  
catch(Exception e){e.printStackTrace ();} $_.t'8F  
} 5Tl5T&  
b| L;*<KU  
<C`bf$ak  
//获得文件长度 EFX2>&mWo8  
public long getFileSize() [q9B"@X  
{ 0*{(R#  
int nFileLength = -1; \YvG+7a  
try{ Dz}i-tw+  
URL url = new URL(siteInfoBean.getSSiteURL()); [ws _ g,/  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); &N}"4  
httpConnection.setRequestProperty("User-Agent","NetFox"); e9LX0=  
~` tuPk~l  
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int responseCode=httpConnection.getResponseCode(); i2<z"v63  
if(responseCode>=400) u&zY>'}zm  
{ 5 ^{~xOM5  
processErrorCode(responseCode); *Soi  
return -2; //-2 represent access is error Tz,-~mc  
} 5Kzt8Tv[  
{ZeY:\G~  
Fd9[Pe@?`  
String sHeader; Ud/>oaW?s  
m\>gOTpA4  
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for(int i=1;;i++) `D+zX
 
{ Olzw)Wj
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//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 5%,3)H{;t  
//Utility.log(in.readLine()); pCKP{c=6Q  
sHeader=httpConnection.getHeaderFieldKey(i); /2K"Mpf8  
if(sHeader!=null) K6v~!iiK$  
{ I5"wa:Z  
if(sHeader.equals("Content-Length")) ^+(5[z  
{ Q>1BOH1by  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Z=Y29V8  
break; <nk|Z'G E  
} Nc+0_|,  
} >G`p T#  
else hU
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break; %1#\LRA(  
} '{d_q6,%  
} ,3:f4e\<  
catch(IOException e){e.printStackTrace ();} T~UDD3  
catch(Exception e){e.printStackTrace ();} +5y^c|L0  
";/]rwHa)  
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Utility.log(nFileLength); ZKi&f,:  
'w:ugb9]  
6P{bUom?  
return nFileLength; y [Vd*8  
} +<E#_)}`D6  
P'~`2W0sz  

>2#<gp3  
//保存下载信息（文件指针位置） er3Mvw  
private void write_nPos() 6))":<J  
{ v`4w=!4  
try{ 9^*RK6  
output = new DataOutputStream(new FileOutputStream(tmpFile)); %H\b5& _y  
output.writeInt(nStartPos.length); HI5NWd
fRl  
for(int i=0;i<nStartPos.length;i++) t'_EcYNS  
{ 2}^=NUM\NX  
// output.writeLong(nPos); {6u)EJ  
output.writeLong(fileSplitterFetch.nStartPos); kff N0(MR  
output.writeLong(fileSplitterFetch.nEndPos); #S7oW@  
} >LPb>t5%p  
output.close(); 7-S?RU]g  
} !8@yi"n  
catch(IOException e){e.printStackTrace ();} P>_O :xD  
catch(Exception e){e.printStackTrace ();} 2Bt/co-~4  
} yi8vD~aA[  
i#:To |\u  
b!H1|7>  
//读取保存的下载信息（文件指针位置） gJ l^K  
private void read_nPos()  +P(*S  
{ Gamn
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try{ <EC"E #p  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); aImzK/  
int nCount = input.readInt(); t jM9EP  
nStartPos = new long[nCount]; rxp|[>O<  
nEndPos = new long[nCount]; C^q|(G)  
for(int i=0;i<nStartPos.length;i++)
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{ &g?GF\Y  
nStartPos = input.readLong(); g1t6XVS$9  
nEndPos = input.readLong(); 3,i j@P  
} ld(60?z>FH  
input.close(); i9 aR#  
} !Yc:yF  
catch(IOException e){e.printStackTrace ();} !gI0"p?  
catch(Exception e){e.printStackTrace ();} o@A`AA9  
}  ~&~4{  
c|<F8n  
hNc8uV{r=  
private void processErrorCode(int nErrorCode) CVO_F=;  
{ xa`xHh{0  
System.err.println("Error Code : " + nErrorCode); ,!> ~izB  
} 4Uny.C]  
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t'K+)OK  
//停止文件下载 ;"D}"nL  
public void siteStop() d- ZUuw  
{ L

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bStop = true; +  }"+  
for(int i=0;i<nStartPos.length;i++) 2*snMA  
fileSplitterFetch.splitterStop(); mc]+j,d  
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} 1e\cJ{B  
} [>NMuwtG  
//负责部分文件的抓取 %Za}q]?  
**FileSplitterFetch.java IYn`&jS{  
*/ )B]"""J  
package NetFox; wXQu%F3  
~2*LWH*@  
]{=y8]7  
import java.io.*; -gGw_w?)(  
import java.net.*; M2%@bETJ  
jNxTy UU  
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public class FileSplitterFetch extends Thread { #GGa,@O  
kO)Y|zQ  
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String sURL; //File URL X!h>13fW  
long nStartPos; //File Snippet Start Position !$98U~L  
long nEndPos; //File Snippet End Position { {?-& yA  
int nThreadID; //Thread's ID J>R$K  
boolean bDownOver = false; //Downing is over ^.J_w  
boolean bStop = false; //Stop identical SB%D%Zx6'%  
FileAccessI fileAccessI = null; //File Access interface POk5+^  
=.s0"[%   
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException cPcH 8Vd  
{ i>S@C@~  
this.sURL = sURL; /@ emE0  
this.nStartPos = nStart; W(s5mX,Kv  
this.nEndPos = nEnd; 1*A^v  
nThreadID = id; bF9.k  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 &Sb)a  
} ]6(%tU  
8}yrsF#  
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public void run() XR]bd  
{ ;):;H?WS|A  
while(nStartPos < nEndPos && !bStop) &wDZ@{h  
{ <e! TF@  
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try{ _'!qOt7D  
URL url = new URL(sURL); .+(ED  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); h,y_^cf  
httpConnection.setRequestProperty("User-Agent","NetFox"); UD14q~ (1Z  
String sProperty = "bytes="+nStartPos+"-"; :YLs]JI<  
httpConnection.setRequestProperty("RANGE",sProperty); Wx}-H/t'2  
Utility.log(sProperty); -e$ T}3IV  
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InputStream input = httpConnection.getInputStream(); 4Kt0}W  
//logResponseHead(httpConnection); =zH)R0!eG  
F u5zj\0J  
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byte[] b = new byte[1024]; ~;6^n  
int nRead; *_YH}U  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 0vEQgx>  
{ qbQdxKk  
nStartPos += fileAccessI.write(b,0,nRead); .0,G4k/yv  
//if(nThreadID == 1) a{ke%
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// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); &W3srJo  
} t[;-gi,,  
5OPvy,e6  
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Utility.log("Thread " + nThreadID + " is over!"); v~x`a0  
bDownOver = true; c)Ng9p  
//nPos = fileAccessI.write (b,0,nRead); cGs&Kn;h  
} PE;<0Cz\  
catch(Exception e){e.printStackTrace ();} 3 }sy{Mx%9  
} fP 3eR>e  
} ]Ky`AG`2~  
N MkOx$  
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//打印回应的头信息 Qn$YI9t  
public void logResponseHead(HttpURLConnection con) W $mw9  
{ d lAb`ne  
for(int i=1;;i++) l?b*T#uIk  
{ '_Q';T_n99  
String header=con.getHeaderFieldKey(i); )Ko~6.:5H  
if(header!=null) z(,j)".  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); +P+h$gQ  
Utility.log(header+" : "+con.getHeaderField(header)); >KQ/ c  
else <iH
   
break; L{1[:a)']B  
} $ r-rIW5\  
} djoP`r  
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public void splitterStop() IR3+BDE)>  
{ N`d%4)|{  
bStop = true; _s<BXj  
} 'A3*[e|OS  
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} d" 0&=/  
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/* ^N^s|c'  
**FileAccess.java )l(DtU!E  
*//文件访问(定位，写) NZG ^B/  
package NetFox; |F\fdB}?S:  
import java.io.*; U:@tdH+A7  
jT]R"U/Q  
./zzuKO8XK  
public class FileAccessI implements Serializable{ ;FuST  
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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  `wIWK7i  
RandomAccessFile oSavedFile; C2b<is=H:  
long nPos; k|RY; 8_  
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public FileAccessI() throws IOException ,jW a&7  
{ I\-M`^@  
this("",0); UCj<FN `  
} YuHXm3[  
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@o1#J`rv  
public FileAccessI(String sName,long nPos) throws IOException "9X!Ewm"P  
{ vqVwo\oEdU  
oSavedFile = new RandomAccessFile(sName,"rw"); Kv:.bHN}  
this.nPos = nPos; pI.8Ip_r  
oSavedFile.seek(nPos); u^i3@JuX  
} .qf~t/o  
4\ElMb[]  
}fef*>>}  
public synchronized int write(byte[] b,int nStart,int nLen) 5zZQt+Ip  
{ BhjDyB  
int n = -1; BaUuDo/ZO  
try{ Q t>|TGz  
oSavedFile.write(b,nStart,nLen); ]R!YRu  
n = nLen; <EE^ KR96  
} M(C$SB>  
catch(IOException e) vxi_Y\r=T  
{ !?J-Y  
e.printStackTrace (); 5-H"{29  
} PQ;9iv  
B>I:KGkV  
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return n; +BhJske  
} S{)K_x  
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} Hj`\Fm*A  
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/* RU/SJ1wM"  
**SiteInfoBean.java I#]pk!  
*/ 6f t6;*,  
package NetFox; >Y\?v-^~;  
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@.)[U:N  
public class SiteInfoBean { xzFQ)t&  
[wJ\.9<Oa  
/ $s(OFbi#  
private String sSiteURL; //Site's URL M^e}w!U  
private String sFilePath; //Saved File's Path 5yj#9H  
private String sFileName; //Saved File's Name OTAe#]#  
private int nSplitter; //Count of Splited Downloading File O:~J_Wwl!  
MXDCOe~07  
 !I&,!$  
public SiteInfoBean() P1^|r}  
{//nSplitter的缺省值为5 3xdJ<Lrq  
//default value of nSplitter is 5 Q Wc^}#!!  
this("","","",5); %\
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} AOwmPHEL  
IAN={";p  
0S&J=2D!  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) mfffOG  
{ E.0J94>iM  
sSiteURL= sURL; `|v/qk7 ^?  
sFilePath = sPath; z;/8R7L&  
sFileName = sName; D6fd(=t1Z  
this.nSplitter = nSpiltter; 'qG-
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R>&8%%#  
} \L}7.fkb8  
l,3,$  
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public String getSSiteURL() 62Tel4u  
{ xpu2RE  
return sSiteURL; f<|*^+  
} 3zc;_U2  
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public void setSSiteURL(String value) xsy45az<ip  
{ ;R<V-gab  
sSiteURL = value; ,!PV0(F(  
} B&1E&Cv_8  
f#7=N
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\  
public String getSFilePath() GDiyFTr  
{ ,Jn` qvmi  
return sFilePath; 4M6[5RAW{  
} w-NTw2x,&  
Tdz#,]Q   
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public void setSFilePath(String value) 3J/l>1[  
{ )iK:BL*Nw  
sFilePath = value; cW"DDm g  
} jP2#w{xq  
|b^UPrz)VS  
$A/?evJi8R  
public String getSFileName() d%nX;w,   
{ 1A#/70Mo  
return sFileName; OQKc_z'"  
} ,q7FK z{  
7|
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3-1a+7fD  
public void setSFileName(String value) .j>MsQP#\C  
{ OA} r*Wz  
sFileName = value; 23,pVo  
} J6>tGKa+e  
_%\%  
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public int getNSplitter() WB<MU:.Vc  
{ gf9U<J#&C  
return nSplitter; S;D]
ym  
} bGy|T*@  
@de0)AJG6  
9HlWoHuC  
public void setNSplitter(int nCount) a'n17d&  
{ d+ZXi'  
nSplitter = nCount; cD)9EFo  
} dD~H ft  
} f5{|_]q]  
<r>Sj/w<D  
WiQVZ{  
/* o1*P|.`  
**Utility.java 3p?nQ O)L  
*/ C+%eT&
OO  
package NetFox; DnG9bVm>  
z}Us+>z+jc  
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public class Utility { F+ RE  
b353+7"|  
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public Utility() i3d2+N`  
{ 0w< ilJ  
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} iWFtb)3B  
>ke.ZZV?  
//线程睡眠 oR,zr  
public static void sleep(int nSecond) _iEnS4$A8  
{ "O|.e`C%^  
try{ | WTWj  
Thread.sleep(nSecond); .jC5 y&  
} kt\,$.
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catch(Exception e) EA9.?F  
{ jENC1T(  
e.printStackTrace (); _O11SiP]  
} d<HO~+9  
} jAv3qMQA  
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//日志  4~ L1~Gk  
public static void log(String sMsg) . &`Y
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{ >}2 ,2  
System.err.println(sMsg); 0E,QOF{o  
} fR+{gazk n  
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KhX)maQ  
public static void log(int sMsg) fE&s 6w&  
{ nt-_)4Fm  
System.err.println(sMsg); r:E4Wi{\  
} }[drR(]`dO  
} _8F;-7Sz  
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;3xi.^=B  
/* gy~2LY!}  
**TestMethod.java `-R&4%t%  
*/ v}
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package NetFox; *QIYq  
wJp1Fl~  
I|>.&nb  
public class TestMethod { J7aYi]vI  
/me ]sOkn  
@p}_"BHYWt  
public TestMethod() %hw4IcWJ|  
{ ///xx/weblogic60b2_win.exe KIR3m )  
try{ LpSF*xm  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 2QEH!)lvr  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); .J&89I]U  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 5} ur,0{  
fileFetch.start(); <sM_zoprc  
} U>bIQk"4  
catch(Exception e){e.printStackTrace ();} 'irwecd8  
` "-P g5  
e8oAGh"  
} ~Cw7.NA{3  
!$ii*}  
=h +SZXe<r  
public static void main(String[] args) }Qe(6'l_  
{ D^P0X:T]  
new TestMethod(); %zRuIDmv  
} r!eW]M  
} N;BuBm5K  
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