http断点续传简单实现（java)

/* N7%=K9  
**SiteFileFetch.java I*%&)Hj~  
*/ Di]Iy  
package NetFox; `,<>){c|  
import java.io.*; K1CMLX]m  
import java.net.*; g=)U_DPRi  
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tauP1&%oH{  
public class SiteFileFetch extends Thread {  W"#j7p`d  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ZhxfI?i)l  
long[] nStartPos; //开始位置 w4>:uyE  
long[] nEndPos; //结束位置 h?M'7Lti  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 a'(lVZA;  
long nFileLength; //文件长度 DRS;lJ2  
boolean bFirst = true; //是否第一次取文件 ZfF`kD\  
boolean bStop = false; //停止标志 4p0IBfVG  
File tmpFile; //文件下载的临时信息 uugzIV)  
DataOutputStream output; //输出到文件的输出流 E}E7VQjM  
!^Qb[ev  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） cJ1{2R  
public SiteFileFetch(SiteInfoBean bean) throws IOException AF07KA#  
{ K[Ws/yc^a  
siteInfoBean = bean; k N uN4/  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); j8F~j?%!  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); @vDgpb@TM  
if(tmpFile.exists ()) xf{C'uF/  
{ bTI&#Hu  
bFirst = false; 1yY'hb,0  
read_nPos(); &)/H?S;yN  
}
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else S(YHwH":  
{ 0n=9TmE  
nStartPos = new long[bean.getNSplitter()]; {&Gk.ODI7  
nEndPos = new long[bean.getNSplitter()]; vf/$`IJ  
} }r\SP3  
8EVF<@{]  
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} A,A-5l<h]?  
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public void run() U_=wL  
{  Cq~ah  
//获得文件长度 jwtXI\@MS  
//分割文件 y("0Xve  
//实例FileSplitterFetch S'H0nJ3  
//启动FileSplitterFetch线程 4jZi62  
//等待子线程返回 `U?H^,FVA  
try{ "ZK5P&d
 
if(bFirst) h-)A?%Xt  
{ 1V?Sj
  
nFileLength = getFileSize(); K:Xrfn{s  
if(nFileLength == -1) `'tw5}  
{ IQ27FV|3  
System.err.println("File Length is not known!"); F.* snF  
} \?`d=n=  
else if(nFileLength == -2) xF:poi  
{ C">=2OO  
System.err.println("File is not access!"); wW)&Px n  
} ]mGsNQ ].H  
else ,uD*FSp>  
{ L)//- k9  
for(int i=0;i<nStartPos.length;i++) QW"6]  
{ :Pp;{=J  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); E'kQ  
} 3YNkT"~T  
for(int i=0;i<nEndPos.length-1;i++) KzH}5:qI  
{ RAkFgC~  
nEndPos = nStartPos[i+1]; &Bdt+OQ ;  
} g)G7 kB/<p  
nEndPos[nEndPos.length-1] = nFileLength; 0?*I_[Y  
} R`3>0LrC8  
} g>oYEFFJ  
z E7ocul  
i:Ct6[  
//启动子线程 <OO/Tn'a  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; (P!reYyM  
for(int i=0;i<nStartPos.length;i++) mUY:S |  
{ an5kR_=  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), LB ^^e"  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), a0j.\g  
nStartPos,nEndPos,i); 0tL/:zID  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); OL9C#er  
fileSplitterFetch.start(); RxeRO2  
} 7JwWM2N?V  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), z=h5  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); WBIB'2:m  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", [/,6O  
nEndPos = " + nFileLength); |JQP7z6j]  
// fileSplitterFetch[nPos.length-1].start(); c\
rbLr}l)  
i&G`ah>  
<`p'6n79  
//等待子线程结束 =FJ9wiL  
//int count = 0; "._WdY[  
//是否结束while循环 z4`n%~w1b  
boolean breakWhile = false; Wjk;"_"gd  
l@F e(^5E  
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while(!bStop) A,[m=9V  
{ P FFw$\j  
write_nPos(); )Ua2x@j'C@  
Utility.sleep(500); q9(}wvtr  
breakWhile = true; =F-^RnO%\  
Id
7  
%~VIxY|d  
for(int i=0;i<nStartPos.length;i++) ;xH'%W9z  
{ qtQ:7WO  
if(!fileSplitterFetch.bDownOver) _~q^YZ  
{ <%f%e4 [  
breakWhile = false; C$;s+ALy[  
break; SF=|++b1f  
} WbzL!zLd!  
} * rANf&y  
if(breakWhile) jCv+m7Z  
break; zate%y  
> V}NG  
eh(]'%![/  
//count++; .7rsbZzs  
//if(count>4) &.4a  
// siteStop(); .Vjpkt:H  
} rz7b
%
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/7)G"qG~F~  
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System.err.println("文件下载结束！"); *Yjs$'_2  
} iW$i%`>  
catch(Exception e){e.printStackTrace ();} uCr  
} 8+|Lph`/?  
eajL[W^>  
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//获得文件长度 ;BvWU\!  
public long getFileSize() 0evZg@JP`  
{ `<Nc Y*  
int nFileLength = -1; &bx,6dX  
try{ J>v>6OC6i  
URL url = new URL(siteInfoBean.getSSiteURL()); Wm_-T]#_  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); `Yve  
httpConnection.setRequestProperty("User-Agent","NetFox"); C@W0fz  
UG$i5PV%i  
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int responseCode=httpConnection.getResponseCode(); <O&s 'A[  
if(responseCode>=400) `-2`UGB-  
{ x7>sy,c  
processErrorCode(responseCode); $OuA<-  
return -2; //-2 represent access is error ~!u94_:  
} jqmP^ZS  
`Y9@?s Q  
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String sHeader; Yuck]?#0  
c6.|; 4  
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for(int i=1;;i++) lPP7w`[PA  
{ 2x CGr>X  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ::w%rv  
//Utility.log(in.readLine()); KDk^)zv%!  
sHeader=httpConnection.getHeaderFieldKey(i); #,
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if(sHeader!=null) vzPrG%Uu7g  
{ p};<l@  
if(sHeader.equals("Content-Length")) +bU(-yRy5o  
{ 3f x!\  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 
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break; \WEC1+@  
} *2Kte'+q  
} =s<QN*zJB0  
else T%F'4_~No  
break; N0NMRU]zT  
} n&lLC&dL  
} 4}`MV.  
catch(IOException e){e.printStackTrace ();} iuRXeiG8  
catch(Exception e){e.printStackTrace ();} pK%'S  
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}z6HxB]$  
Utility.log(nFileLength); W%x#ps5%  
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[ q}WS5Cp  
return nFileLength; e5Z\v0  
}  [iz  
7Uh}|6PU  
'=5N?)  
//保存下载信息（文件指针位置） ?0F#\0  
private void write_nPos() .x&>H  
{ . x$` i  
try{ 1RLSeT  
output = new DataOutputStream(new FileOutputStream(tmpFile)); e3.TGv7=  
output.writeInt(nStartPos.length); m`|+_{4[n  
for(int i=0;i<nStartPos.length;i++) >ObpOFb%  
{ :Wln
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// output.writeLong(nPos); vv3?ewr y  
output.writeLong(fileSplitterFetch.nStartPos); 9;jfg|x1[  
output.writeLong(fileSplitterFetch.nEndPos); TD@'0MaQ#  
} ^gy(~u  
output.close(); am=56J$ig  
} mdwY48b  
catch(IOException e){e.printStackTrace ();} 5M3QRJ!  
catch(Exception e){e.printStackTrace ();} YV9%^ZaN7  
} G:UdU{  
$JOIK9+3z#  
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//读取保存的下载信息（文件指针位置） a&&EjI  
private void read_nPos() PO#FtG  
{ ~0`Pe{^*  
try{ ]l4\/EW6  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 3|C"F-'<  
int nCount = input.readInt(); >?5`F
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nStartPos = new long[nCount]; oR~+s&c  
nEndPos = new long[nCount]; ;9rQN3J$gn  
for(int i=0;i<nStartPos.length;i++) /H)l\m +  
{ TYp{nWwi  
nStartPos = input.readLong(); i''dY!2  
nEndPos = input.readLong(); E-RbFTVBA  
} 3B,nHU  
input.close(); (7"qT^s3  
} wM><DrQ  
catch(IOException e){e.printStackTrace ();} lps  
catch(Exception e){e.printStackTrace ();} &#WTXTr0=  
} r`lgK2r\  
!-: a`Vs+  
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private void processErrorCode(int nErrorCode) a].Bn#AH!C  
{ Dq\#:NnKvx  
System.err.println("Error Code : " + nErrorCode); y};qo'dlt  
}  X(bb1  
j,Mp["X&  
\4V'NTjB  
//停止文件下载  -"<eq0  
public void siteStop() J9/w_,,R$  
{ z\fk?Tj<ro  
bStop = true; 9~N7hLT  
for(int i=0;i<nStartPos.length;i++) UF}fmDi  
fileSplitterFetch.splitterStop(); u+{5c5_  
5e/%Tue.  
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} o#;w>-  
} bBjVot  
//负责部分文件的抓取 2t_E\W7w+  
**FileSplitterFetch.java :5;[Rg5 2  
*/ g-6!+>w*>e  
package NetFox; T `N(=T^*  
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tEb2>+R  
import java.io.*; 7 0KZXgBy_  
import java.net.*; m"u 9AOHk  
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| YvO$4=s  
public class FileSplitterFetch extends Thread {
}P^{\SDX  
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iTD{  
String sURL; //File URL 594$X@!v  
long nStartPos; //File Snippet Start Position G$ipWi  
long nEndPos; //File Snippet End Position F YcC2TM  
int nThreadID; //Thread's ID ARslw*SJ  
boolean bDownOver = false; //Downing is over yl|+D]  
boolean bStop = false; //Stop identical  c,x2  
FileAccessI fileAccessI = null; //File Access interface K&Zdk (l)  
3&_(D)+  
;b(/PH!O  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException h%#@Xd>.  
{ 9'O<d/xj/  
this.sURL = sURL; %N>@( .  
this.nStartPos = nStart; ,v(G2`Z  
this.nEndPos = nEnd; #uKHw2N  
nThreadID = id; }K0.*+M  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 m_oBV|v{  
} ==Ju2D?%  
`Q}.9s_ri  
U.d*E/OR5  
public void run() 8&H1w9NrX_  
{ +HUI1@ql  
while(nStartPos < nEndPos && !bStop) bSBI[S  
{ Dr<%Lr  
#kk_iS>8  
h|_G2p^J+"  
try{  5Gg`+o  
URL url = new URL(sURL); 'Zk&AD ~  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ykM(` 1`m  
httpConnection.setRequestProperty("User-Agent","NetFox"); 7-bU9{5  
String sProperty = "bytes="+nStartPos+"-"; R>#T{<<L  
httpConnection.setRequestProperty("RANGE",sProperty); "!r7t4  
Utility.log(sProperty); H<dm;cU  
zI(b#eUF  
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InputStream input = httpConnection.getInputStream(); uflp4_D   
//logResponseHead(httpConnection); X=_N7!  
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v:<u0B-)$  
byte[] b = new byte[1024]; 8%I4jL<  
int nRead; ,!PNfJA2  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ;w[|IRa  
{ F71.%p7C8"  
nStartPos += fileAccessI.write(b,0,nRead); %q(n'^#Z.y  
//if(nThreadID == 1) bQEQHqY5  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); )=ZWn,ZB  
} MvJEX8M  
kQwBrb4  
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Utility.log("Thread " + nThreadID + " is over!"); o=4d2V%m  
bDownOver = true; &`0heJ 5Yn  
//nPos = fileAccessI.write (b,0,nRead); FtT+Q$q=  
} WZ;f3 "  
catch(Exception e){e.printStackTrace ();} g@KS\.m]  
} tb^3-ZUb  
} -.i1l/FzP  
9kQ~)4#  
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//打印回应的头信息 OT\[qaK  
public void logResponseHead(HttpURLConnection con) \KDOI7  
{ xsV(xk4  
for(int i=1;;i++) kT!FC0E{  
{ f4CwyL6ur  
String header=con.getHeaderFieldKey(i); i{ eDV  
if(header!=null) n"-cX)  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); }vPDCUZ  
Utility.log(header+" : "+con.getHeaderField(header)); _hM3p  
else \<]nv}1O  
break; &=xm>;`3  
} e(,sFhR  
} r[JgCj+$&  
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public void splitterStop() 7P.C~,+D%P  
{ t/#[At5p=  
bStop = true; r,EIOcz:  
} 4JT9EKo
 
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} d {T3  
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"fL:scq@0  
/* 5kof
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**FileAccess.java d/j$_NQ&!  
*//文件访问(定位，写) =ugxPgn  
package NetFox; +79?}|  
import java.io.*; r}+U1l3#2  
&zynfj#
o  
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public class FileAccessI implements Serializable{ r~si:?6:  
'@3hU|jO!  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ez"Xb 7  
RandomAccessFile oSavedFile; > 't=r  
long nPos; }`{aeVHT  
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public FileAccessI() throws IOException 0-oR { {  
{ Mp:tcy,*  
this("",0); [ft#zxCJ  
} SYOND>E  
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D ?1$I0=  
public FileAccessI(String sName,long nPos) throws IOException pE[ul  
{ 3U!\5Nsby  
oSavedFile = new RandomAccessFile(sName,"rw"); 35%'HFt_  
this.nPos = nPos; HW;,XzP=  
oSavedFile.seek(nPos); Em N0K'x  
} wyzj[PDS  
):  
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public synchronized int write(byte[] b,int nStart,int nLen) 2M3.xUS  
{ Yc/Nz(m  
int n = -1; A% 9TS/-p  
try{ )@DH&  
oSavedFile.write(b,nStart,nLen); E5w.wx  
n = nLen; )q&=x2`  
} RMMx6L|-:  
catch(IOException e) K'+GK S7.  
{ -ve{
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e.printStackTrace (); #/Y t
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} 7^4F,JuJO  
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return n; 6UXa 5t  
} ()6)|A<^U  
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} 5M4mFC6  
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/* W2G`
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**SiteInfoBean.java Ml1yk)3G  
*/ 3/+9#  
package NetFox; >Ip>x!wi  
D$ zKkPYI  
p:U9#(v)  
public class SiteInfoBean { )eop:!m  
/.l8Jb4  
]
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private String sSiteURL; //Site's URL S/Pffal  
private String sFilePath; //Saved File's Path n&Bolt(tO  
private String sFileName; //Saved File's Name 2qLRcA=R  
private int nSplitter; //Count of Splited Downloading File PXof-W  
>H?l[*9  
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public SiteInfoBean() 1A"h!;0  
{//nSplitter的缺省值为5 %p6"Sg*  
//default value of nSplitter is 5 ;A7
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this("","","",5); q[`)A?Ae  
} xjB2?:/2  
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+O>!x#)&"  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter)
6Ko[[?Lf[  
{ 0i/l2&x*k]  
sSiteURL= sURL; Fn.wd`'0  
sFilePath = sPath; Rs,\{#  
sFileName = sName; nQ2V  
this.nSplitter = nSpiltter;
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} RO"c+|Py  
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public String getSSiteURL() ieXhOA  
{ rt)70=  
return sSiteURL; G&$+8r  
} }w .[ZeP  
@9~a3k|  
w=5D>]  
public void setSSiteURL(String value) F`KA^ZI  
{ t:NTk(  
sSiteURL = value; +>mbBu!7  
} {E`[`Kf  
UUi@ U  
}PdS?[R  
public String getSFilePath()
,tJ%t#  
{ ZlD\)6 dZ  
return sFilePath; !i=LQUi.  
} 7.)e4  
\x?q!(;G2  
[mX/]31  
public void setSFilePath(String value) >a7'_n_o  
{ F0h`>{1%  
sFilePath = value; WBT/;),}:  
} ?,~B@Kx  
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;v%Fw!b032  
public String getSFileName() ?u.&BP  
{ 5ZeE& vG2  
return sFileName; /W&Ro5-  
} _aa3
;kT_  
tSX<^VER7  
iq'hel  
public void setSFileName(String value)
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{ -U/"eVM  
sFileName = value; KW.*LoO  
} /
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A;~lG3j4  
:xOne<@  
public int getNSplitter() +-tvNX%IJ  
{ ~\_aT2j0  
return nSplitter; +oa\'.~?  
} ?/ xk  
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i#Tm] ++  
public void setNSplitter(int nCount) (iub\`  
{ RsV<4$  
nSplitter = nCount; egQB!%D  
} ?sfas57&y  
} Zzy!D  
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/* Q9,H0r-%  
**Utility.java 8m%+O#  
*/ "|P8L| @*  
package NetFox; \Tf[% Kt x  
6*yt^[W  
_}MO.&Y  
public class Utility { zN}1Qh  
hM}rf6B  
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public Utility() -|E|-'  
{ #p'Xq }]  
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.|>zQ(7YC  
} \XDc{c]  
S$9>9!1>*  
//线程睡眠 u!kC+0Y  
public static void sleep(int nSecond) <}e2\x  
{ V>"nAh]}.  
try{ u,h,;'J  
Thread.sleep(nSecond); VVY#g%(K
 
} mOiA}BGw  
catch(Exception e) IE/F =Wr  
{ 3FWl_d~uD  
e.printStackTrace (); {NmpTb  
} tE&@U$0>o  
} :|j,x7&/{  

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//日志 | %E\?-TK  
public static void log(String sMsg) ]J<2a`IK!  
{ )=,%iL-  
System.err.println(sMsg); ]IX6>p,  
} j_=A)B?  
>lyX";X#  
:exgdm;N  
public static void log(int sMsg) *g0}pD;r  
{ _
8*}S=
 
System.err.println(sMsg); 2'R;z<_  
} P''5A6#5  
} )C?bb$ G  
\*>r[6]*&5  
3Z,J&d`[  
/* &b!L$@6  
**TestMethod.java aQ@9(j> F  
*/ Cxn<#Kf\-<  
package NetFox; e_eNtVq  
!Q-h#']~L  
w$ zX.;s  
public class TestMethod { %[1\d)  
gmCW__oR  
M84{u!>[  
public TestMethod() "nkj_pC  
{ ///xx/weblogic60b2_win.exe 5m.{ayE  
try{ G9`;Z^<L  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); {zTo[i  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); $0uh8RB  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 4CUoXs'  
fileFetch.start(); A&HN7C%X  
} |rjHH<  
catch(Exception e){e.printStackTrace ();} U8f!yXF'  
Xv1SRP#  
nRP|Qt7>  
} DC&3=Nd  
h=:*cqp4  
{P'_s]B)  
public static void main(String[] args) 0_!')+  
{ /G{;?R  
new TestMethod(); \a_75^2  
} %l4;-x<e  
} 2)iwAu   
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