http断点续传简单实现（java)

/* Q{ |+3!!'  
**SiteFileFetch.java XZUB*P}]D  
*/ /h}wM6pg  
package NetFox; 7$Z)fkx.  
import java.io.*; T2/v}  
import java.net.*; 46
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public class SiteFileFetch extends Thread { )zk?yY6  
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SiteInfoBean siteInfoBean = null; //文件信息Bean L~?,6  
long[] nStartPos; //开始位置 8S[<[CH  
long[] nEndPos; //结束位置 /Gh x2B  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 l\A}lC0?J  
long nFileLength; //文件长度 ".*a)  
boolean bFirst = true; //是否第一次取文件 ;Wfv+]n9  
boolean bStop = false; //停止标志 l"~h1xk~  
File tmpFile; //文件下载的临时信息 vJ#rW8y  
DataOutputStream output; //输出到文件的输出流 5~ *'>y  
wHo#%Y,Nmi  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） vMW-gk  
public SiteFileFetch(SiteInfoBean bean) throws IOException flm,r<*}  
{ P@! Q1pr  
siteInfoBean = bean; 4:
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//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ^=-*
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tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); k`iq<b  
if(tmpFile.exists ()) 's7SZ$(  
{ M rH%hRV6R  
bFirst = false; qw Kh,[]  
read_nPos(); gOES2 4$2  
} g#9*bF  
else K\Y6 cj  
{ fxtYo,;$  
nStartPos = new long[bean.getNSplitter()]; @'NaA SB  
nEndPos = new long[bean.getNSplitter()]; n'x`oI)-  
} XSHwE)m  
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} iBPdCp%]`  
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public void run() x9{Sl[2&  
{ HPd+Bd  
//获得文件长度 EkgN6S`}  
//分割文件 BHRrXC\  
//实例FileSplitterFetch 8YJqM,t5)  
//启动FileSplitterFetch线程 u6bB5(s`&  
//等待子线程返回 wzLiVe-  
try{ CpP$HrQ  
if(bFirst) B 3,ig9  
{ Fm[?@Z&wP  
nFileLength = getFileSize(); Vqv2F @.  
if(nFileLength == -1) DY+8m8!4H  
{ e) /u>I  
System.err.println("File Length is not known!"); yW6[Fpw  
} a s<q  
else if(nFileLength == -2) Lu#@~  
{ /KJxn6  
System.err.println("File is not access!"); MRl*rK  
} /S=;DxZ,r  
else 2}xFv2X  
{ |Z^c#R  
for(int i=0;i<nStartPos.length;i++) )lngef /D_  
{ 1+PNy d  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); gp|7{}Q{  
} 'k(~XA}X:  
for(int i=0;i<nEndPos.length-1;i++) Q+%m+ /Zq  
{ ~1wdAq`'a  
nEndPos = nStartPos[i+1]; >FMT#x t  
} TF}4X;3Dsy  
nEndPos[nEndPos.length-1] = nFileLength; \ /X!tlwxh  
} WHD/s  
} :xUl+(+  
iYfLo">  
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//启动子线程 {dSU \':  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; iR}i42Cu  
for(int i=0;i<nStartPos.length;i++) S;AnpiBM8  
{ A](}"Pi!n  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), JXR/K=<^  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), @*`UOgP7
 
nStartPos,nEndPos,i); 2"{]A;@  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); :Ro" 0/d  
fileSplitterFetch.start(); wGQhr="  
} 5)zh@aJ@  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); F*jjcUk  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 4`5Qt=}  
nEndPos = " + nFileLength); o!_
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// fileSplitterFetch[nPos.length-1].start(); R;-FZ@u/  
[{!j9E?(  
!&:W1Jkp(  
//等待子线程结束 /*p?UW<*4  
//int count = 0; 2.L6]^N p(  
//是否结束while循环 63dtO{:4  
boolean breakWhile = false; M0IqQM57N  
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while(!bStop) h*X%:UbW  
{ yLa5tv/  
write_nPos(); "E[*rnsLN  
Utility.sleep(500); n YMf[kW  
breakWhile = true; Cq;K,B9  
<IkD=X  
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for(int i=0;i<nStartPos.length;i++) YHv,Z|.w  
{ MVU'
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if(!fileSplitterFetch.bDownOver) U!UX"r  
{ qxCL  
breakWhile = false; 2dJ)4  
break; `r0 qn'*  
} 3/|{>7]1  
} % |Gzht\  
if(breakWhile) X|lmH{k
f  
break; \U =>  
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//count++; uXW. (x7"f  
//if(count>4) i$<v*$.o  
// siteStop(); U,3K6AZA 7  
} nsw8[pk  
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System.err.println("文件下载结束！"); K~~*M?.Z  
} H.G^!0j;  
catch(Exception e){e.printStackTrace ();} ia.B@u1/  
} [&}<!:9'  
;%.k}R%O@  
|q b92|?  
//获得文件长度 ?|rw=%  
public long getFileSize() Gg,k  
{ T`0gtSS  
int nFileLength = -1; {.8)gVBmA  
try{ 3K]0sr  
URL url = new URL(siteInfoBean.getSSiteURL()); WD`{kq
c  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); GM56xZ!2T  
httpConnection.setRequestProperty("User-Agent","NetFox"); ~=gH7V  
u^.k"46hn  
:qKY@-t7H  
int responseCode=httpConnection.getResponseCode(); 00x^zu?N  
if(responseCode>=400) Q2WrB+/  
{ 8}b[Q/h!  
processErrorCode(responseCode); ~=]@],{  
return -2; //-2 represent access is error k 5kX  
} iYs?B0*JWK  
3\~fe/z'I  
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String sHeader; >N"PLSY1  
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for(int i=1;;i++) p" W0$t.  
{ z`{zqP:  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); l]=$<  
//Utility.log(in.readLine()); EF{'J8AQ  
sHeader=httpConnection.getHeaderFieldKey(i); d33Nx)No  
if(sHeader!=null) 7027@M?A?  
{ `5jB|
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if(sHeader.equals("Content-Length")) fszeJS}Dw  
{ X51$5%  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Fd.d(  
break; PS;*N8  
} dV*rnpN  
} 3sIM7WD?  
else jJC((1|  
break; JT_B@TO\  
} $d[:4h~  
} lD=j/  
catch(IOException e){e.printStackTrace ();} `r$WInsDu  
catch(Exception e){e.printStackTrace ();} UoT}m^ G  
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Utility.log(nFileLength); w:(7fu=  
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return nFileLength; vK~KeZ\,p=  
} 4?uG> ;V  
UwT$IKR  
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//保存下载信息（文件指针位置） YhR"_  
private void write_nPos() ,QAp5I%3=  
{ Y}z?I%zL  
try{ nit7|T@^  
output = new DataOutputStream(new FileOutputStream(tmpFile)); *dgN
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output.writeInt(nStartPos.length); !Hj)S](F  
for(int i=0;i<nStartPos.length;i++) |^!@
  
{ 5W-M8dc6  
// output.writeLong(nPos); ;itg>\p3  
output.writeLong(fileSplitterFetch.nStartPos); rmJ847%y`  
output.writeLong(fileSplitterFetch.nEndPos); <Wq{ V;$  
} /hR]aw  
output.close(); Mc^7FWkw  
} ?LM'5  
catch(IOException e){e.printStackTrace ();} f_Bf}2Eedj  
catch(Exception e){e.printStackTrace ();} DMW:%h{  
} (fb\A6  
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//读取保存的下载信息（文件指针位置） C{^@.8:  
private void read_nPos() iP_Xr~w  
{ ^<+heX  
try{ ^Z+D7Q  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); >1zzDd_  
int nCount = input.readInt(); zt}p-U2I  
nStartPos = new long[nCount]; ,KaWP  
nEndPos = new long[nCount]; EOC"a}Cq-  
for(int i=0;i<nStartPos.length;i++) fdW={}~  
{ bd}SB-D  
nStartPos = input.readLong(); ?QVI'R:Z
?  
nEndPos = input.readLong(); W<l(C!{  
} brot&S2P><  
input.close(); T6#GlO)8)  
} 11+_OC2-   
catch(IOException e){e.printStackTrace ();} !7?wd^C'f  
catch(Exception e){e.printStackTrace ();} L<`g}iw  
} 9x,+G['Zt  
C =U4|h~W  
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private void processErrorCode(int nErrorCode) OO>2oH  
{ pBLO  
System.err.println("Error Code : " + nErrorCode); ??Ac=K\  
} 1^dWmxUZH  
L,L7WObA  
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//停止文件下载 v:;cTX=x`#  
public void siteStop() 5!*a,$S  
{ q>X2=&1  
bStop = true; D3ad2vH  
for(int i=0;i<nStartPos.length;i++) 4F!d V;"Z(  
fileSplitterFetch.splitterStop(); [N)M]u  
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} G> >_G<x  
} !CKUkoX  
//负责部分文件的抓取 h65j,v6B  
**FileSplitterFetch.java rg
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*/ H)tDfk sq\  
package NetFox; F{tSfKy2  

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import java.io.*; RGmpkQEp  
import java.net.*; Ymom 0g+f  
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public class FileSplitterFetch extends Thread { O6]~5&8U.  
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(z7#KJ1+Aw  
String sURL; //File URL Y2n*T KXI,  
long nStartPos; //File Snippet Start Position 566Qikw2  
long nEndPos; //File Snippet End Position qzz'v  
int nThreadID; //Thread's ID Ip0q&i<6  
boolean bDownOver = false; //Downing is over X Rn=;gK%J  
boolean bStop = false; //Stop identical 5@ug1F&  
FileAccessI fileAccessI = null; //File Access interface ): 6d_g{2  
`Fj(g!`  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException nCU4a1rZ  
{ se[};t:  
this.sURL = sURL; x#D=?/~/Kv  
this.nStartPos = nStart; & j43DYw4  
this.nEndPos = nEnd; o*_D  
nThreadID = id; cht#~d  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 s9iM hCu|  
} kns]P<g  
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public void run() zKNk(/y  
{ sXu]k#I^"  
while(nStartPos < nEndPos && !bStop) n>WS@b/o  
{ OjZ@_V:  
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try{ fvDwg  
URL url = new URL(sURL); }wVrmDh \  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 9!LAAE`  
httpConnection.setRequestProperty("User-Agent","NetFox"); (Gcl,IW  
String sProperty = "bytes="+nStartPos+"-"; J}JnJV8|G  
httpConnection.setRequestProperty("RANGE",sProperty); S4w/ kml3  
Utility.log(sProperty); 5S1m&s5k  
a;K:~R+@,  
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InputStream input = httpConnection.getInputStream(); _D~a4tgS  
//logResponseHead(httpConnection); 5j]%@]M$Z  
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byte[] b = new byte[1024]; U^xFqJY6  
int nRead; nV,a|V5Xm  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) `d8TA#|`  
{ 3r\QLIr L8  
nStartPos += fileAccessI.write(b,0,nRead); P1t5-q  
//if(nThreadID == 1) \4ZQop  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); <x/&Ml+  
} <6@Db$-  

>2a~hW|,  
/W9=7&R0  
Utility.log("Thread " + nThreadID + " is over!");
*$QUE0  
bDownOver = true; "k.<"p
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//nPos = fileAccessI.write (b,0,nRead); B4kIcHA  
} N$?qAek  
catch(Exception e){e.printStackTrace ();} Jps!,Mflc  
} <%5ny!]  
} -8
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//打印回应的头信息 ^#nAS2w7U  
public void logResponseHead(HttpURLConnection con) ||hd(_W8  
{ mwt3EV5  
for(int i=1;;i++) (j(6%U  
{ n'SnqJ&}  
String header=con.getHeaderFieldKey(i); RW'QU`N[Y  
if(header!=null) |q?A8@\u  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); |.YL2\  
Utility.log(header+" : "+con.getHeaderField(header)); ='(:fHhhX  
else )/UkJ/}j  
break; |g~.]2az  
} 8"+Kz  
} !^y'G0  
*cf#:5Nl  
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public void splitterStop() j s
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{ 4oJ0,u  
bStop = true; :p89J\  
} KcHW>IBxdv  
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} d%iMjY`~[g  
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7"1M3P5*8  
/* rAgb<D@,H  
**FileAccess.java &4L
rV+`$V  
*//文件访问(定位，写) Z<`QDBN"4  
package NetFox; @I9A"4Im  
import java.io.*; F&^u1RYz  
H
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J%{>I  
public class FileAccessI implements Serializable{ q>t#5Z81  
MGK%F#PM  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 !IcPO  
RandomAccessFile oSavedFile; T< D&%)  
long nPos; cJMp`DQzc  
*y0TtEd;  
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public FileAccessI() throws IOException S/V%<<[>p]  
{ }Ge$?ZFH  
this("",0); Dc2H<=];  
} xcty  
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JD9)Qelw^$  
public FileAccessI(String sName,long nPos) throws IOException dSkMA  
{ `p#tx.o  
oSavedFile = new RandomAccessFile(sName,"rw"); !cW6dc^  
this.nPos = nPos; vhvFBx0  
oSavedFile.seek(nPos); yvv]iRk<  
} 7_HFQT1.N  
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]l
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public synchronized int write(byte[] b,int nStart,int nLen) ]Q$Sei5  
{ FF#T"y0Y  
int n = -1; 7H.3.j(L  
try{ XlLG/N  
oSavedFile.write(b,nStart,nLen); 5If.[j{  
n = nLen; *O_>3Hgl  
} F/V-@SF  
catch(IOException e) 6dgwsl~  
{ ^p)#;$6b  
e.printStackTrace (); [n4nnmM  
} j<'ftK
k  
f*}}Az.4  
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return n; M0yv=g  
} uP G\1  
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} Me79:+d  
z
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/* A3)"+`&PUl  
**SiteInfoBean.java eSQkW  
*/ p4V*%A&w  
package NetFox; {]2^b)  
]VL} eHZ  
4sRM"w;  
public class SiteInfoBean { 9 ,:#Q<UM  
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private String sSiteURL; //Site's URL yts@cd`$  
private String sFilePath; //Saved File's Path ?5FlbiT  
private String sFileName; //Saved File's Name %N)B8A9kh  
private int nSplitter; //Count of Splited Downloading File qg{gCG  
6R,Y.srR  
d(|q&b
:  
public SiteInfoBean() oUwo!n}  
{//nSplitter的缺省值为5 )X-'Q-  
//default value of nSplitter is 5 $33E-^  
this("","","",5); <l(n)|H1P  
} d7Vp^^}(  
O 2-n-  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) /cb`%"Z  
{ ?h6|N%U'  
sSiteURL= sURL; {;DAKWm@T  
sFilePath = sPath; ]L97k(:Ib  
sFileName = sName; <Xl#}6II  
this.nSplitter = nSpiltter; uLa
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0u1ZU4+EC  
jB(+9?;1${  
} ydyTDn  
ss[`*89  
D3cJIVM  
public String getSSiteURL() PFuhvw~?  
{ "aOs#4N  
return sSiteURL; GuO}CQs^W  
} /kY9z~l  
l3sF/zkH  
jd](m:eG  
public void setSSiteURL(String value) _;BwP  
{ -T,?'J0 2  
sSiteURL = value; .Q%Hi7JMi  
} ux<|8S  
l)9IgJ|<b  
. :Skc  
public String getSFilePath() eCYPd-d  
{ 5Jbwl$mZ  
return sFilePath; iX$G($[l(  
} hI'WfF!X  
`Gqe]ZE#"  
tw_o?9  
public void setSFilePath(String value) jc&k-d>=G  
{ j{%;n40$  
sFilePath = value; _K o#36.S  
} j|t=%*  
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public String getSFileName() UGSZg|&6#*  
{ d5$D[,`1  
return sFileName; I8Aq8XBw  
} 5dePpFD5  
IMkE~0x4</  
oX|T&"&  
public void setSFileName(String value) L[x`i'0B  
{ XOvJlaY)'.  
sFileName = value; BS9VwG<Z  
} ,U~A=bsa  
=rA?,74  
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public int getNSplitter() G-d7}Uz?  
{ z`zz8hK.  
return nSplitter; aV\i3\da  
} 2? qC8eC  
PVIOe}N  
P8eCaZg?(3  
public void setNSplitter(int nCount) O] @E8<?^  
{ #L*\^ c  
nSplitter = nCount; 1Gsh%0r3  
} IRN,=  
}
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o701RG~)  
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/* @7Ec(]yp  
**Utility.java t7f(%/] H0  
*/ wlXs/\es  
package NetFox; -8 uS#  
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bf_ >?F^  
public class Utility { {KG}m
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\n{#r`T  
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public Utility() #Zdh<.   
{ K(+=V)'Dz  
JWNN5#=fQ  
@Tu`0=8  
} C m:AU;  
w){B$X
  
//线程睡眠 zDvV%+RW)  
public static void sleep(int nSecond) ``/L18  
{ j9fBl:Fr  
try{ nt2b}u>*  
Thread.sleep(nSecond); > "hP  
} jwI2T$  
catch(Exception e) JN8Rh  
{ |Yli~Qx  
e.printStackTrace (); 9C7Npf?~M  
} ntIR#fB  
} v?He]e'  
HM% +Y47a  
//日志 RvR.t"8  
public static void log(String sMsg) f&vMv.  
{ n*[ZS[I  
System.err.println(sMsg); T6/P54S  
} ]!TE  
ef
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;-3&yQ7N)  
public static void log(int sMsg) 
Q&I #  
{ Z66Xj-o  
System.err.println(sMsg); "~VKUvDu  
} 6.]~7n  
} B2NIV
7  
(PPC?6s  
uihH")Mo  
/* 3FvVM0l"  
**TestMethod.java ! VT$U6  
*/ ;gL{*gR]S  
package NetFox; GJ
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.c>6}:ye  
public class TestMethod { >)D=PvGlmp  
|cd"cx+  
%f<>Kwr`2  
public TestMethod() B*:I-5  
{ ///xx/weblogic60b2_win.exe 6D]fDeH\  
try{ _p"u~j~%-  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); zHKP$k8  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); )&E]  
SiteFileFetch fileFetch = new SiteFileFetch(bean); i=/hLE8T*  
fileFetch.start(); RR=WD-l  
} %KVmpWku  
catch(Exception e){e.printStackTrace ();} l[~$9C'ji  
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i+(>w'=m  
} I
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HT/!+#W.  
public static void main(String[] args) /*;a6S8q  
{ Zr
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new TestMethod(); oAifM1*0  
} z#Qe$`4&  
} \A^8KVE!  
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