http断点续传简单实现（java)

/* X/BcS[a  
**SiteFileFetch.java AW<"3 !@  
*/ sS{!z@\Lf  
package NetFox; M 8NWQ^Y  
import java.io.*; 4.e0k<]N`  
import java.net.*; %y|L'C,ge"  
MLT^7'y  
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public class SiteFileFetch extends Thread { r "uQ|
 
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SiteInfoBean siteInfoBean = null; //文件信息Bean 5<$8.a#  
long[] nStartPos; //开始位置 J?%ecCN  
long[] nEndPos; //结束位置 3j7Na#<tL3  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 @#QaaR;4  
long nFileLength; //文件长度 `e[>S  
boolean bFirst = true; //是否第一次取文件 <Toy8-kj  
boolean bStop = false; //停止标志 6>NK2} `  
File tmpFile; //文件下载的临时信息 ){I!orQ  
DataOutputStream output; //输出到文件的输出流 q@&6&cd  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） {2.zzev'  
public SiteFileFetch(SiteInfoBean bean) throws IOException OK" fFv  
{ ?1.WF}X'  
siteInfoBean = bean;
7CwQmVe+  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Ib(G!oO:E-  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); (.pi,+Ws  
if(tmpFile.exists ()) n@$("p  
{ 6PyW(i(bs  
bFirst = false; N;` jz(r  
read_nPos(); U ATF}x  
} S;^'Ek"Z.  
else @%"r69\  
{ LsxRK5  
nStartPos = new long[bean.getNSplitter()]; BZOB\Ym  
nEndPos = new long[bean.getNSplitter()]; lx{ ' bzv  
} 3|Y2BAd  
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} pEp$J;   
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public void run() G{74o8  
{ . e_VPKF|  
//获得文件长度 |,Kk#`lW<f  
//分割文件 :MihVLF  
//实例FileSplitterFetch ~%
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//启动FileSplitterFetch线程 tx7B?/5D  
//等待子线程返回 {BY(zsl  
try{ %n^ugm0B  
if(bFirst) : G'a
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{ LeV";=_n  
nFileLength = getFileSize(); <Rfx`mn  
if(nFileLength == -1) k&9[}a*  
{ Bn{i+8I  
System.err.println("File Length is not known!"); wx8Qz,Z  
} Q9Vj8JO"{  
else if(nFileLength == -2) 4Opf[3]  
{ 4I8QM&7  
System.err.println("File is not access!"); /'a\$G"%6  
} w0X})&,{`m  
else cD t|v~  
{ 12@Ge]  
for(int i=0;i<nStartPos.length;i++) ~gdnD4[G  
{ ?c
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); SUDvKP  
} WP{U9YF2  
for(int i=0;i<nEndPos.length-1;i++) 9aBz%* xo  
{ w>e+UW25Y  
nEndPos = nStartPos[i+1]; NG8F'=<  
} L{0\M`B-  
nEndPos[nEndPos.length-1] = nFileLength; {>Hn:jW<.  
} MZ?+I~@  
} TVF:z_M9  
hmB`+?,z*  
@<3kj R?j  
//启动子线程 }wZsM[
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; :JU$6  
for(int i=0;i<nStartPos.length;i++) ;+1ooeU  
{ d&lT/S  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), S$=caZ?  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), -/:!AxIH  
nStartPos,nEndPos,i); NiYT%K%  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 5<M$ XT  
fileSplitterFetch.start(); \dbaY:(  
} pVM1%n:#  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 7 lSR  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); N/eus"O;  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", " {X0&  
nEndPos = " + nFileLength); \D1@UyE  
// fileSplitterFetch[nPos.length-1].start(); `!xI!Y\  
\5-Dp9vG  
E`Br#"/Bl  
//等待子线程结束 .kTOG'K\e  
//int count = 0; ;ojJXH~$}  
//是否结束while循环 g
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boolean breakWhile = false; A2!pbeG  
e8M0Lz#}  

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while(!bStop) i91k0q*di  
{ TR%8O;  
write_nPos(); yg6o#;  
Utility.sleep(500); wq|7sk{  
breakWhile = true; Nza@6nI"  
oI
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for(int i=0;i<nStartPos.length;i++) 6n|][
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{ 4+89 M  
if(!fileSplitterFetch.bDownOver) [_`@V4  
{ k;K-6<^h  
breakWhile = false; 0+k..l  
break; C~WWuju'  
} A-, hm=?  
} 6E2#VT>@/  
if(breakWhile) |h\A5_0_  
break; _4T7Vg''  
KAi_+/]K_  
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//count++; #ro$$I;  
//if(count>4) 4];>
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// siteStop(); lavy?tFer  
} $1Fn
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hkRqtpYK  
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System.err.println("文件下载结束！"); b`JS&E  
} v4K! BW  
catch(Exception e){e.printStackTrace ();}
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} "Th;YJu  
*\B(-  
6ma.FvSIM  
//获得文件长度 `(DHa=s1  
public long getFileSize() mM~&mAa+Z  
{ JmeE}:5lpj  
int nFileLength = -1; U5OFw+J  
try{ #M<YNuE#"  
URL url = new URL(siteInfoBean.getSSiteURL()); M& )yr^  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); i(Zz
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httpConnection.setRequestProperty("User-Agent","NetFox"); HCx0'|J  
~'|^|*}~Dj  
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int responseCode=httpConnection.getResponseCode(); 4l>U13~#  
if(responseCode>=400) Z|fi$2k0!  
{ 4TyzD%pOw  
processErrorCode(responseCode); AAqfp/DC  
return -2; //-2 represent access is error B%`|W@v  
}  FLZ9Rg  
s:cJF  
?2R!n"m-d  
String sHeader; 76]Z~^Y  
zl|+YjR  
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for(int i=1;;i++) $Ld-lQsL  
{ 2 6 >9$S  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); hL&7D@  
//Utility.log(in.readLine()); Vk*XiEfKm>  
sHeader=httpConnection.getHeaderFieldKey(i); s>1\bio*I  
if(sHeader!=null) :S}ZF$ $j%  
{ C,%Dp0  
if(sHeader.equals("Content-Length")) zqURnsJ  
{ ).0p\.W~  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); K7C!ZXw~  
break; j&U7xv  
} Vk2%yw>  
} @4KKm@(p85  
else w `+.F;}s  
break; -x:7K\=$SX  
} ,%qP   
} !T2{xmHKv$  
catch(IOException e){e.printStackTrace ();} $5\!ws<cZ  
catch(Exception e){e.printStackTrace ();}
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Utility.log(nFileLength); y
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97<Z,q72Y  
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return nFileLength; C~
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} (D6ks5Uui  
_00}O+GLM4  
[mNum3e  
//保存下载信息（文件指针位置） wkx#WC  
private void write_nPos() $at\aJ  
{ +t&+f7  
try{ Z[l+{  
output = new DataOutputStream(new FileOutputStream(tmpFile)); bKsEXS  
output.writeInt(nStartPos.length); `Y+R9bd  
for(int i=0;i<nStartPos.length;i++) 9Y2.ob!$}  
{ D=Nt0y  
// output.writeLong(nPos); oB>#P-V  
output.writeLong(fileSplitterFetch.nStartPos); /x]^Cqe  
output.writeLong(fileSplitterFetch.nEndPos); LN5BU,4=  
} hN*v|LFf1  
output.close(); $=#Lf[|f=  
} m-a':  
catch(IOException e){e.printStackTrace ();} '4D7:  
catch(Exception e){e.printStackTrace ();} *3OlWnZ?  
} Bn%?{z)  
*_mER`  
Q[%G`;e#  
//读取保存的下载信息（文件指针位置） J_j4Zb% K  
private void read_nPos() >e(@!\ x  
{ O_GHvLO=  
try{ >wL!`:c'"  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); "=KFag  
int nCount = input.readInt(); MRZN4<}9  
nStartPos = new long[nCount]; ZsCwNZR  
nEndPos = new long[nCount]; Nf2lw]-G4  
for(int i=0;i<nStartPos.length;i++) 7xY&7 x(v  
{ :7X{s4AU6  
nStartPos = input.readLong(); Vq/hk
  
nEndPos = input.readLong(); 1|s`z  
} +fKV/tSWi  
input.close(); ;8 *"c  
} %rf6>  
catch(IOException e){e.printStackTrace ();} __1Hx?f  
catch(Exception e){e.printStackTrace ();} XMykUr e|  
} ~|"uuA1/#O  
6i~<,;Cn  
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private void processErrorCode(int nErrorCode) ydRS\l  
{ :8
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System.err.println("Error Code : " + nErrorCode); &j/,8 Z*  
} /J Y6S  
1}SON4U  
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//停止文件下载 Os].
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public void siteStop() :oYSvK7>  
{ 3q@H8%jcw  
bStop = true; ]/3!t=La  
for(int i=0;i<nStartPos.length;i++) s jaaZx1  
fileSplitterFetch.splitterStop(); <lU(9) L;&  
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} 8Fbt >-N<\  
} S$P=;#r  
//负责部分文件的抓取 ;9-J=@KY4  
**FileSplitterFetch.java 0,):;OI  
*/ jq_4x[  
package NetFox; jeO`45O  
n=0^8QQ  
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import java.io.*; ,J<+Wxz  
import java.net.*; w@YPG{"j  
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public class FileSplitterFetch extends Thread { aI}htb{m`  
FP
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@at*E%T[  
String sURL; //File URL "(~fl<;  
long nStartPos; //File Snippet Start Position OwgPgrV  
long nEndPos; //File Snippet End Position D vN0h(?  
int nThreadID; //Thread's ID paYS<8In  
boolean bDownOver = false; //Downing is over G9#3 |B-?  
boolean bStop = false; //Stop identical _5p]Arg?}&  
FileAccessI fileAccessI = null; //File Access interface E@l@f
 
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException jROh3kq  
{ X4Uy3TV>  
this.sURL = sURL; _{}^]ZB  
this.nStartPos = nStart; [Z;H=`  
this.nEndPos = nEnd; jaVx9FR+  
nThreadID = id; U[q39FR  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 1N{ >00  
} h+cOOm-)  
P!)F1U]!  
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public void run() ^)$T`  
{ 7s{['t  
while(nStartPos < nEndPos && !bStop) )7AjRtb!/  
{ _W,?_"[R=  
.lI.I  
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try{ xk,1D
 
URL url = new URL(sURL); RUut7[r  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); bGwj` lue  
httpConnection.setRequestProperty("User-Agent","NetFox"); B4c;/W-  
String sProperty = "bytes="+nStartPos+"-"; 5nmE*(  
httpConnection.setRequestProperty("RANGE",sProperty); f{\[+>  
Utility.log(sProperty); 8{7'w|/;.{  
Q&PEO%/D  
;Yg/y  
InputStream input = httpConnection.getInputStream(); N ;n55N  
//logResponseHead(httpConnection); N[DKA1Ei  
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byte[] b = new byte[1024]; `d x.<R#,  
int nRead; qjf4G[]!  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) O -p^S  
{ V4
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nStartPos += fileAccessI.write(b,0,nRead); WS1Y maV  
//if(nThreadID == 1) V.yDZ"  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); uMZ<i}  
} qA25P<  
- s{&_]A~  
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Utility.log("Thread " + nThreadID + " is over!"); hsQ*ozv[)  
bDownOver = true; l~@ -oE  
//nPos = fileAccessI.write (b,0,nRead); MQy,[y7I  
} EIg:@o&Jj  
catch(Exception e){e.printStackTrace ();} ?8<R)hJa<  
} B7%m7GM  
} THy   
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//打印回应的头信息 M{Vi4ehOq  
public void logResponseHead(HttpURLConnection con) 3XUsw1,[  
{ C [8='i26  
for(int i=1;;i++) N]|)O]/[  
{ lZ`@ }^&  
String header=con.getHeaderFieldKey(i); ;H]]H!  
if(header!=null) />7G  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); UVsF !0  
Utility.log(header+" : "+con.getHeaderField(header)); fnFIw=d  
else 1=~##/at  
break; `YBHBTG'o!  
} `#j;\  
} PBwKRD[I  
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public void splitterStop() 9~l8Qa
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{ xR&Le/3+  
bStop = true; 1nE`Wmo.2  
} <bywi2]z  
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} Bv6~!p  
"""eU,"  
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/* 9; aOUs:<  
**FileAccess.java X}&Y(kOT  
*//文件访问(定位，写) gzyi'K<  
package NetFox; \YsLVOv%:d  
import java.io.*; v.Q+4 k  
5hlS2fn  
N_VWA.JHt  
public class FileAccessI implements Serializable{ @4]
dv> Z  
#/hXcF  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 IBh?vh  
RandomAccessFile oSavedFile; )hfI,9I~  
long nPos; uC 2
{ Mmy  
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public FileAccessI() throws IOException |W|RX3D  
{ <VT|R~  
this("",0); okbW. ~  
} [R/'hH5  
!XF:.|  
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public FileAccessI(String sName,long nPos) throws IOException -&np/tEu&  
{ ;7m
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oSavedFile = new RandomAccessFile(sName,"rw"); N6!9QIu~i  
this.nPos = nPos; ^4a|gc  
oSavedFile.seek(nPos); h)X"<a++N  
} X`k#/~+0  
OkQtM nq  
oUN;u*  
public synchronized int write(byte[] b,int nStart,int nLen) 1@^*tffL:  
{ kAAD&t;w  
int n = -1; kY~o3p<  
try{ 6CNxb
  
oSavedFile.write(b,nStart,nLen); IvB)d}p  
n = nLen; 
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} A_|X54}w&  
catch(IOException e) Twk,R. O  
{ \U HI%1^  
e.printStackTrace (); xG,L*3c{o  
} OH`|aqN  
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return n; U#(#U0s*-  
} %I%OHs  
\7*"M y*  
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} EN@<z;  
7)l+hZ  

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/* C\1x3  
**SiteInfoBean.java `4t*H>:y  
*/ 5uL!Ae  
package NetFox; $1bzsB|^  
Y:]m~-T  
tS3{y*yi  
public class SiteInfoBean { WCwM+D  
~JDVoS;>jU  
w\5;;9_#  
private String sSiteURL; //Site's URL 9S<atMB  
private String sFilePath; //Saved File's Path !<4=@  
private String sFileName; //Saved File's Name SG-Xgr@  
private int nSplitter; //Count of Splited Downloading File rSNaflYAr  
RhSoD.Da  
[?VkwFD0  
public SiteInfoBean() 7DWHADr  
{//nSplitter的缺省值为5 42.y.LtZ  
//default value of nSplitter is 5 ::p(ViYG  
this("","","",5);  <4D.H  
} .2QZe8"  
)t$o0!  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) (aSY.#;  
{ _F tI2G9  
sSiteURL= sURL; crr#tad.  
sFilePath = sPath; .=/TT|eMS  
sFileName = sName; >VB*Xt\C&  
this.nSplitter = nSpiltter; !2]'S=Y  
})5I/   
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} DM3 %+ xY  
7H_*1_%ZQ  
*T
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public String getSSiteURL() 3KN})
*1  
{ t@3y9U$  
return sSiteURL; OEXa^M4x   
} >vfbXnN  
rHD_sC*  
fwz-)?   
public void setSSiteURL(String value) 2D'$  
{ 3 UG UZ  
sSiteURL = value; e c4vX  
} .v_-V?7  
*dX 7  
t4r%EP|Zt  
public String getSFilePath() U6LENY+Ja  
{ Ec l/2  
return sFilePath; LAU\.d  
} 1t< nm)  
|)b:@q3k+n  
lD@`xq.M;  
public void setSFilePath(String value) ;&ypvKG  
{ )LjW=;(b  
sFilePath = value; 'XW9+jj)/  
} e>!=)6[*  
p[7?0 (  
=~ [RG  
public String getSFileName() ]seOc],4  
{ ?j@(1",=&  
return sFileName; R9)"%SO<y  
} \'-E[xNcWI  
V8"m_  
9]PMti  
public void setSFileName(String value) 2HF_kYZ  
{ Y3?)*kz%  
sFileName = value; y}GFtRNG  
} B
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)^LiALh  
%O\zYtQR  
public int getNSplitter() \??20iz  
{ Q;y)6+VU4  
return nSplitter; 3u~V&jl  
} %v,a3^Qu  
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P|QM0GI  
public void setNSplitter(int nCount) -5d^n\CDK  
{ J @^Ypq  
nSplitter = nCount; tu5T^"BqO  
} 0^>b=a  
} 4-JyK%m,0  
W9/HM!  
S$ Z?T  
/* }ISc^W) t  
**Utility.java VrnZrQj<  
*/ Ktn:6=,  
package NetFox; #-8%g{  
 -wQ@z6R  
5LJ0V  
public class Utility { }5]7lGR  
9oTtH7%  
7)dCdO  
public Utility() b;IzK'  
{ J)._&O$  
0Q!/A5z  
!YENJJ  
} cN%@ nW0i  
KK, t!a  
//线程睡眠 _o'a|=Osx>  
public static void sleep(int nSecond) g1&>.V}!  
{ EClx+tz;`  
try{ \x
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Thread.sleep(nSecond); T*jQzcm~?  
} 6}>CP
i#  
catch(Exception e) i>%A0.9  
{ (DY&{vudF  
e.printStackTrace (); uo-1.[9ds  
} eNu]K,rT  
} @|EWif|  
sr-tZ^d5S?  
//日志 jhH&}d9  
public static void log(String sMsg) ) m(!lDz3  
{ g+3_ $qIQ+  
System.err.println(sMsg); A\ r}V-  
} <7_s'UAL!  
?ZP@H _w6}  
vE&K!k`  
public static void log(int sMsg) 9NeHN@D)  
{ Y@ X>ejk"  
System.err.println(sMsg); )LTX.Kg  
} N^f_hL|:9  
} .,<w_=  
q0L\{  
*>E_lWW.  
/* W:
JR\KKU  
**TestMethod.java o'K= X E  
*/ |o<c`:;kt  
package NetFox; sQBKzvFO3  
jr/IU=u*v  
`APeS=< &  
public class TestMethod { G.]'pn  
!3`X Gg  
jx14/E+^  
public TestMethod() qi$nG_<<Z  
{ ///xx/weblogic60b2_win.exe %>Mcme>(W  
try{ u4|)A4n  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 5O[\gd-  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); #@L5yy2  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 1|:'jK#gE  
fileFetch.start(); /<1zzeHRSD  
} +h@ZnFp3  
catch(Exception e){e.printStackTrace ();} ca<OG;R^  
DdqE6qE  
xM=?ES  
} Jk;dtLL}4  
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public static void main(String[] args) 1>L8EImx]V  
{ Zmm6&OZ%  
new TestMethod(); kK=f@
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} mcTC'. 9  
} z||FmL{  
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