http断点续传简单实现（java)

/* /#SfgcDt  
**SiteFileFetch.java 1]5k lJ  
*/ < W`gfpzO  
package NetFox; G
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import java.io.*; mqHH1}  
import java.net.*; /$]S'[5uF  
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public class SiteFileFetch extends Thread { F?"Gln~;  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ],[<^=|  
long[] nStartPos; //开始位置 [Gv8Fn/aG  
long[] nEndPos; //结束位置 g6aqsa  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 !bCL/[  
long nFileLength; //文件长度 !lL `L\  
boolean bFirst = true; //是否第一次取文件 q :~/2<o  
boolean bStop = false; //停止标志 iY?#R&  
File tmpFile; //文件下载的临时信息 lMh>eX  
DataOutputStream output; //输出到文件的输出流 s]6;*mI2  
tU2#Z=a  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） vnVT0)Lel  
public SiteFileFetch(SiteInfoBean bean) throws IOException 4X7J~  
{ n1JV)4Mv  
siteInfoBean = bean; }CMGK
{  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ~@PD\  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); =M4:nt  
if(tmpFile.exists ()) 8#tuB8>  
{ }uC]o@/  
bFirst = false; [>pBz3fn,  
read_nPos(); _'1 ]CoR  
} )*XWe|H_  
else *`wz  
{ @RszPH1B  
nStartPos = new long[bean.getNSplitter()]; vzbGLap#  
nEndPos = new long[bean.getNSplitter()]; !G[%; d  
} 0gW{6BtPWm  
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} ]Q0bL  
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public void run() 0%[IG$u)|  
{ 9kF0H a}J  
//获得文件长度 8q{|nH  
//分割文件 ^xNzppz`]C  
//实例FileSplitterFetch "M-';;  
//启动FileSplitterFetch线程 M
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//等待子线程返回 ){#INmsF  
try{ -ZSN0Xk  
if(bFirst) 3
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{ |94o P>d  
nFileLength = getFileSize(); dL'oKh,  
if(nFileLength == -1) v6=%KXSF  
{ o@.{|j  
System.err.println("File Length is not known!"); {5X,xdzR  
} D]*|Zmr+}  
else if(nFileLength == -2) %dW;P[0  
{ ,<#Rk'y$  
System.err.println("File is not access!"); uI?Z_  
} DW9MX`!Xc  
else n YUFRV$  
{ P;z\vq<h  
for(int i=0;i<nStartPos.length;i++) RC1bTM  
{ 82EvlmD  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); *'A*!=5(  
} #;^UW  
for(int i=0;i<nEndPos.length-1;i++) 0?/gEr  
{
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nEndPos = nStartPos[i+1]; E' `;  
} V~/-e- 9u  
nEndPos[nEndPos.length-1] = nFileLength; "p;tj74O9  
} 1`L.$T,1!  
} P)f8lU^z  
2 G*uv+=  
|k*bWuXgLs  
//启动子线程 u1y>7,Z6W  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; PpG;5  
for(int i=0;i<nStartPos.length;i++) ^Ld5<  
{ H.;}%id  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), y6d!?M(0U  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), G]k[A=dg  
nStartPos,nEndPos,i); _,(s  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); j?|V
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fileSplitterFetch.start(); RDHK'PGA  
} >I~Q[  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), [@VzpVhXz  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 5,^DT15a4P  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", >M{98NH  
nEndPos = " + nFileLength); BRY/[QRqZ  
// fileSplitterFetch[nPos.length-1].start(); -['& aey}a  
rL"]m_FK  
8g_kZ^<[  
//等待子线程结束 0<@['W}G  
//int count = 0; xsRkO9x  
//是否结束while循环 #>:S&R?2t  
boolean breakWhile = false; E+XS7':I  
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while(!bStop) z)^.ai,:0  
{ qCrpc=  
write_nPos(); .EHq.cd
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Utility.sleep(500); qfCZ [D  
breakWhile = true; Jv3G\9_  
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for(int i=0;i<nStartPos.length;i++) QbHX
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{ )O+Zbn  
if(!fileSplitterFetch.bDownOver) o@360#njF  
{ #=y)Wuo=  
breakWhile = false; fP4P'eI  
break; fCY??su*   
}  9Ca0Tu  
} LD?\gK"  
if(breakWhile) c9jS !uDMK  
break; G/3T0d+-  
zTMLE~w  
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//count++; MYVVI1A  
//if(count>4) +\ "NPK@3  
// siteStop(); l}(HE+?  
} nJv=kk1|o  
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System.err.println("文件下载结束！"); ~cO
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} ZZHQ?p-  
catch(Exception e){e.printStackTrace ();} n ei0LAD  
} (AjgLNB  
Z6Mjc/  
$i<+O,@-  
//获得文件长度 JBc*m  
public long getFileSize() T3=h7a %=  
{ l SKq  
int nFileLength = -1; wS,fj gX  
try{ \X(*JNQ  
URL url = new URL(siteInfoBean.getSSiteURL()); |%XcI3@*  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); lq3D!+m  
httpConnection.setRequestProperty("User-Agent","NetFox"); ) 5Ij  
qo\9,<  
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int responseCode=httpConnection.getResponseCode(); 6/g 82kqpk  
if(responseCode>=400) 3jW&S  
{ -Mrt%1g  
processErrorCode(responseCode); (#85<|z  
return -2; //-2 represent access is error Pz D30VA  
} ct,;V/Dx  
M?('VOy)  
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String sHeader; /G]/zlUE  
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for(int i=1;;i++) iC!6g|]X  
{ "G*$#  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ui`EODhA(  
//Utility.log(in.readLine()); 6
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sHeader=httpConnection.getHeaderFieldKey(i); yeIS}O  
if(sHeader!=null) >y#qn9rV1  
{ uxKO"  
if(sHeader.equals("Content-Length")) Pq{p\Qkj  
{ 6#
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nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 3gJZlH5IR  
break; (igB'S5wf  
} 6,~1^g*  
} Tu}EAr  
else ,|zzq@fk  
break; d2U?rw_  
} ^ )!eiM  
} o
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catch(IOException e){e.printStackTrace ();} CHO_3QIz  
catch(Exception e){e.printStackTrace ();} p9\*n5{  
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Utility.log(nFileLength); BOA7@Zaa$p  
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a
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return nFileLength; {(Mmv[y  
} `Z{s,!z  
Ii/{xVMD  
-h ^MX  
//保存下载信息（文件指针位置） \4<|QE  
private void write_nPos() rp1+K4]P  
{ >XiT[Ru
 
try{ 2w+4
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output = new DataOutputStream(new FileOutputStream(tmpFile)); {0/2Hw n  
output.writeInt(nStartPos.length); 8gt*`]I  
for(int i=0;i<nStartPos.length;i++) Bzt:9hr6BO  
{ qJonzFp7  
// output.writeLong(nPos); \x4:i\Fx@  
output.writeLong(fileSplitterFetch.nStartPos); DVg$rm`  
output.writeLong(fileSplitterFetch.nEndPos); ?Oy0p8  
} cCx{ ")  
output.close(); ,-(D(J;}1  
} Ayn$,  
catch(IOException e){e.printStackTrace ();} NZ!I >  
catch(Exception e){e.printStackTrace ();} 1#+|RL4o  
} f4d-eXGwx`  
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//读取保存的下载信息（文件指针位置） l1L8a I,8  
private void read_nPos() Cv*K.T  
{ ^Ojg}'.Ygv  
try{ `pDTjJ  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); B#5[PX  
int nCount = input.readInt(); FK-q-PKO#.  
nStartPos = new long[nCount]; jpW_q+^?  
nEndPos = new long[nCount]; gyh8  
for(int i=0;i<nStartPos.length;i++) V=1zk-XC  
{ jr#*;go  
nStartPos = input.readLong(); E&@#*~   
nEndPos = input.readLong(); <_=O0 t|6  
} g$hEVT  
input.close(); b<"jmB{  
} WMWMb3  
catch(IOException e){e.printStackTrace ();} vLq%k+D#  
catch(Exception e){e.printStackTrace ();} SlT>S1`rnG  
} Wy-y-wi:p  
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R  
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private void processErrorCode(int nErrorCode) ~MYE8xrId  
{ o"A)t=  
System.err.println("Error Code : " + nErrorCode); Q^05n$ tI  
} BYa#<jXtAT  
a+~b3  
$o
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//停止文件下载 /<k5"C%z  
public void siteStop() %Kp^wf#o9  
{ VUHf-bKl  
bStop = true; E GZiWBr  
for(int i=0;i<nStartPos.length;i++) 7#
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fileSplitterFetch.splitterStop(); $T7 qd  
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} L=C#E0{i  
} :!?Fq/!  
//负责部分文件的抓取 t6\--lk_  
**FileSplitterFetch.java #mK?:O\-1  
*/ Gui[/iY,F  
package NetFox; uf (_<~  
hJk:&!M=T  
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import java.io.*; Vw`Q:qo0:b  
import java.net.*; -XwS?*O  
%,ScGQE  

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public class FileSplitterFetch extends Thread { Rxlv:  
V U5</si+  
SK 5]7C2  
String sURL; //File URL v
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long nStartPos; //File Snippet Start Position +StsSZ  
long nEndPos; //File Snippet End Position w&J_c8S  
int nThreadID; //Thread's ID 8ZCA vEy  
boolean bDownOver = false; //Downing is over .4$F~!aj9  
boolean bStop = false; //Stop identical [*0M$4  
FileAccessI fileAccessI = null; //File Access interface )vVf- zU  
WQD:~*C:  
1cRF0MI  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException HNj;_S  
{ h9iQn<lp4.  
this.sURL = sURL; 5tZ0zr  
this.nStartPos = nStart; =#<bB)59  
this.nEndPos = nEnd; X{6a  
nThreadID = id; BB(v,W  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 DVKb`KJ"  
} `R.Pz _
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UTN[!0[  
public void run() .P?n<n#  
{ 2Yd@V}  
while(nStartPos < nEndPos && !bStop) [cl+AV "  
{ 9e vQQN6D|  
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try{ N`N?1!fM<}  
URL url = new URL(sURL); Zkqq<  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); *W>, 98  
httpConnection.setRequestProperty("User-Agent","NetFox"); Q1|zX@,  
String sProperty = "bytes="+nStartPos+"-"; 19!;0fe=  
httpConnection.setRequestProperty("RANGE",sProperty); X(3| (1;sV  
Utility.log(sProperty); T.-tV[2  
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9$C?)XKXB  
InputStream input = httpConnection.getInputStream(); X')l04P@%  
//logResponseHead(httpConnection); Ck"db30.  
u&UmI-}  
R osU~OK  
byte[] b = new byte[1024]; O/d]2<V  
int nRead; suGd&eP|  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) T0)b
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{ )EKWsGNe/  
nStartPos += fileAccessI.write(b,0,nRead); hdSP#Y'-  
//if(nThreadID == 1) qfxEo76'  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); DQc\[Gq&  
} LXhR"PWZM\  
s@y;b0
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Utility.log("Thread " + nThreadID + " is over!"); .c0u##/0  
bDownOver = true; v9S=$Aj  
//nPos = fileAccessI.write (b,0,nRead); #Er"i  
} (uhE'IQ{(  
catch(Exception e){e.printStackTrace ();} X7`-dSVE  
} 6-J}ZfGj  
} y'>JT/Q5  
o8hE.pf&  
6?C';1  
//打印回应的头信息 dG]B-(WTC  
public void logResponseHead(HttpURLConnection con) ?K:.Pa  
{ c=9A d
 
for(int i=1;;i++) &1&OXm$  
{ ^yq}>_  
String header=con.getHeaderFieldKey(i); vNl)ltzJF  
if(header!=null)
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//responseHeaders.put(header,httpConnection.getHeaderField(header)); BGwD{6`U  
Utility.log(header+" : "+con.getHeaderField(header)); kN8B,  
else ?TK`sGy  
break; X!'C'3X  
} t,*1=S5  
} 5;XYF0  
UwF-*(#41  
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public void splitterStop() kS9;Tjcx  
{ Md~._@`|K  
bStop = true; YhfQpe  
} /`DKX }  
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} K9p<PL
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/* Tcc83_Iq  
**FileAccess.java ']+!i a  
*//文件访问(定位，写)  G +41D  
package NetFox; \b8#xT}  
import java.io.*; BmccSC;o4  
"e8EA!Ipte  
Hc8He!X*#  
public class FileAccessI implements Serializable{ ``$$yS~d};  
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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 Dc$q0|N=z  
RandomAccessFile oSavedFile; kD%MFT4  
long nPos; I}0?d  
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public FileAccessI() throws IOException \ERxr   
{ *i:8g(  
this("",0); !t"/w6X1I  
} ^v cnDi  
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public FileAccessI(String sName,long nPos) throws IOException CsycR@[  
{ L[Z^4l_!  
oSavedFile = new RandomAccessFile(sName,"rw"); ly0L)L]\  
this.nPos = nPos; ]BbV\#  
oSavedFile.seek(nPos); ?QJx!'Y,p  
} +ZW>JjP*  
t,8?Tf+i  
knG:6tQ  
public synchronized int write(byte[] b,int nStart,int nLen) ?hc=w2Ci  
{ )$9wKk\F  
int n = -1; hp(MKfhH  
try{ /}>8|#U3y  
oSavedFile.write(b,nStart,nLen); xt pY*  
n = nLen; Fs $FR-x  
} %M'`K  
catch(IOException e) g_P98_2f.k  
{ kwT)j(pp<  
e.printStackTrace (); Tc||96%2^  
} /4pYhJ8S  
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return n; =0Y0o_  
} nKr'cb  
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} !]g[u3O  
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/* >TCit1yD  
**SiteInfoBean.java )r
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*/ Tb?XKO,  
package NetFox; db_?da;!`  
6IT6EkiT  
gsM$VaF(  
public class SiteInfoBean { Oi:
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private String sSiteURL; //Site's URL Y#V(CIDe  
private String sFilePath; //Saved File's Path (EWGX |QA  
private String sFileName; //Saved File's Name *'aJO}$  
private int nSplitter; //Count of Splited Downloading File NwYQ6VEA  
af>i  
We}9'X}  
public SiteInfoBean() }DjVZ48  
{//nSplitter的缺省值为5 }[PwA[k'  
//default value of nSplitter is 5 8w[O%  
this("","","",5); > _sSni  
} URm<Ji  
jJ<&!=  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) z-We>KX  
{ Z.@n7G  
sSiteURL= sURL; NkBvN\CQ  
sFilePath = sPath; Y&=DjKoVh  
sFileName = sName; [T7&)p  
this.nSplitter = nSpiltter; &4WA/'>R  
^C^I  
iY@
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} ~s'}_5;VY  
(_}q>3  
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public String getSSiteURL()  bV(BwWm  
{ a6z0p%sIZ  
return sSiteURL; wVf 7<@/y  
} #M w70@6  
v ))`U,Gm  
_UkBOJ:G$H  
public void setSSiteURL(String value) r>bgCQ#-n  
{ \^y~w~g?  
sSiteURL = value; [Nm?qY  
} RZpjr !R  
0$Mxu7 /  
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public String getSFilePath() 4|\M`T  
{ ^2rj);{V  
return sFilePath; _/P;`
@  
} Xqm?@JN  
'NjeF&#6  
4`oKvL9  
public void setSFilePath(String value) i}>EGmv m  
{ 1 <T|  
sFilePath = value; %K\B)HR
 
} e&ZTRgYdi  
{y@8E>y5$  
"X?Zw$gRud  
public String getSFileName() SufM~9Ll  
{ Z&H_+u3j  
return sFileName; Snmv  
} ircL/:  
NzhWGr_x'  
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public void setSFileName(String value) wS7Vo{#@\  
{ C{l-l`:  
sFileName = value; tJtp1$h  
} L*6<h  
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*&_A4)  
public int getNSplitter() o(v7&m;  
{ }NV<k
 
return nSplitter; y[cc<wm$  
} {4[
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public void setNSplitter(int nCount) EXW?)_pg  
{ Mjl,/-0 w  
nSplitter = nCount; qOyS8tA.H  
} b/#<::D `  
} m\ qR myO  
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/* 4RQ38%> >j  
**Utility.java F$:mGyl5_  
*/ drwxrZt   
package NetFox; RJT55Rv{  
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FO]f 4@  
public class Utility { P6v@ Sn  
j~;y~Cx?  
EjEXev<]  
public Utility() %2G3+T8*x  
{ )kKeA  
cZWW[i  
3],(oQq^  
} VWCC(YRU|$  
9/#b1NGv  
//线程睡眠 :2{ [f+  
public static void sleep(int nSecond) `"iPJw14  
{ 7d_"4;K)  
try{ p1z^i(  
Thread.sleep(nSecond); dsK^-e6:5  
} 8h|~>v  
catch(Exception e) _B}QS"A  
{ `E>o:tff  
e.printStackTrace (); UyNP:q:  
} itO1ROmu  
} bG)6p05Oa  
>4T7DMy  
//日志 CTX%~1_`O  
public static void log(String sMsg) ;/^O7KM-  
{ iW?NxP  
System.err.println(sMsg); #Pq6q.UB  
} /q`f3OV"  
mj2sbRiSR=  
Vf(n  
public static void log(int sMsg) {JcMJZ3  
{ dSzq}w4xY  
System.err.println(sMsg);  qJj5_  
} &gvX<X4e  
} -n$hm+S  
6rAenK-%  
t\<*Q3rl-  
/* ]G=^7O]`C!  
**TestMethod.java 4+0:(=>[%  
*/ LoS%FI  
package NetFox; }e,*'mCC*  

EPeV1$  
8DlRD$_:&  
public class TestMethod { Uw>g^[V;  
w
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_d3/="=  
public TestMethod() X]%n#\t,]  
{ ///xx/weblogic60b2_win.exe , @6_sl  
try{ :B4X/  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); sMb+4{W&6  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); zQ,ymfT  
SiteFileFetch fileFetch = new SiteFileFetch(bean); {UEZ:a  
fileFetch.start(); N6S}u@{J~N  
} +p)kemJ~  
catch(Exception e){e.printStackTrace ();} +P 9h%/Yk  
E.rfS$<1  
KZTT2KsYl  
} ais"xm
<V  
25`6V>\  
'd=B{7k@  
public static void main(String[] args) ]1n =O"vE  
{ 9.$k^|~  
new TestMethod(); UPJ3YpK  
} <al/>7z' O  
} IG~d7rh"  
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