http断点续传简单实现（java)

/* n\Z!ff/  
**SiteFileFetch.java ! `  
*/ \=VtHu92=  
package NetFox; :C(=&g<]D  
import java.io.*; ^me-[ 5  
import java.net.*; u%&`}g  
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public class SiteFileFetch extends Thread { (9''MlGd%  
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SiteInfoBean siteInfoBean = null; //文件信息Bean PS)4 I&;U  
long[] nStartPos; //开始位置 pnl{&<$C%C  
long[] nEndPos; //结束位置 jwc
)Lj}  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 E:UW#S%A f  
long nFileLength; //文件长度 fiK6@,  
boolean bFirst = true; //是否第一次取文件 }"nItcp.1  
boolean bStop = false; //停止标志 YqhAZp<  
File tmpFile; //文件下载的临时信息 'nzg6^I7g  
DataOutputStream output; //输出到文件的输出流 $p1(He0 2  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） nsu@h  
public SiteFileFetch(SiteInfoBean bean) throws IOException Xb|:vr\v  
{ B]nEkO'a:  
siteInfoBean = bean; Y071Y:  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath()));  ~^NtO  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); u1J0$  
if(tmpFile.exists ()) Ec!"O3%!M^  
{ .0zY}`  
bFirst = false; ?&8^&brwG  
read_nPos(); {fPy=,>Nb  
} f(>p=%=O  
else J{.{f  
{ NW~N}5T  
nStartPos = new long[bean.getNSplitter()]; so,t  
nEndPos = new long[bean.getNSplitter()]; NO*u9YH?  
} ((YMVe  
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} l.67++_  
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public void run() ~Otq %MQ  
{ #{\J Nb+w%  
//获得文件长度 FvaUsOy
"  
//分割文件 [>jbhV'  
//实例FileSplitterFetch 0at/c-K`  
//启动FileSplitterFetch线程 jZu[n)u'C  
//等待子线程返回 {3|t;ZHk  
try{ |B?cVc0  
if(bFirst) g#"zQvON  
{ HZ aV7dOZ8  
nFileLength = getFileSize(); 1T"`vtR  
if(nFileLength == -1) F|'>NL-=  
{ &p'Y^zL-  
System.err.println("File Length is not known!"); hr#M-K  
} 4`4kfi
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else if(nFileLength == -2) Tm~" IB*  
{ \o z#l'z  
System.err.println("File is not access!"); -R|,9o^  
} 6hno)kd{=  
else ;"a=gr  
{ AFq~QXmr)  
for(int i=0;i<nStartPos.length;i++) M1k{t%M+S  
{ Kr?TxhUHd  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 5#HW2"7  
} iowTLq!?  
for(int i=0;i<nEndPos.length-1;i++) 4GkWRu1  
{ C'>|J9~Gz  
nEndPos = nStartPos[i+1]; !S$:*5=&  
} 8v:T.o;<  
nEndPos[nEndPos.length-1] = nFileLength; %"q9:{m  
} e),q0%5  
} ahJ`T*)
HY  
J9\Cm!H  
2]z8:a  
//启动子线程 prWk2_D;*  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; K?6jXJseb  
for(int i=0;i<nStartPos.length;i++) eQ$Y0qH1E  
{ !44/sr'  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), sfpZc7  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Q)~aiI0  
nStartPos,nEndPos,i); b:U$x20n$  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); t;|@o\  
fileSplitterFetch.start(); Xc=Y  
} MU($|hwiL  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), _('=b/  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); .e
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// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ST|x23|O]  
nEndPos = " + nFileLength); ^P[e1?SZG  
// fileSplitterFetch[nPos.length-1].start(); g?c xp+  
NN%*b yK  
h){0rX@:&  
//等待子线程结束 @D]5civm_  
//int count = 0; [u =+3b  
//是否结束while循环 X
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boolean breakWhile = false; &xU[E!2H%  
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while(!bStop) Q$a{\*[:+  
{ +! ]zA4x  
write_nPos(); DEBB()6,  
Utility.sleep(500); .6ylZ  
breakWhile = true; evya7^,F  
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for(int i=0;i<nStartPos.length;i++) +vw\y  
{ qFicBpB  
if(!fileSplitterFetch.bDownOver) G'nmllB`]  
{ j%Y#(Q>  
breakWhile = false; =Z{O<xw'  
break; =T3<gGM  
} |.(dq^  
} ]Oe2JfJwx  
if(breakWhile) r7RIRg_  
break; t=BUN  
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)~G
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//count++; E:,/!9n  
//if(count>4) sv2A-Dld  
// siteStop(); l?E{YQq]  
} H[NSqu.s  
7!evm;A  
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System.err.println("文件下载结束！"); v3*_9e  
} D.r<QO~6B
 
catch(Exception e){e.printStackTrace ();} 2+RUTOv/d  
} VRVO-Sk  
.Hescg/S  
Rm2yPuOU}A  
//获得文件长度 ~G)S   
public long getFileSize() I )~GZ  
{ ;d@#XIS&-(  
int nFileLength = -1; !`M,XSp(  
try{ 3#
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URL url = new URL(siteInfoBean.getSSiteURL()); h!M  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); %Si6]3-^@  
httpConnection.setRequestProperty("User-Agent","NetFox"); To\QjP-  
X1:V<,}"  
aFl;BhM  
int responseCode=httpConnection.getResponseCode(); i"1Mfz~e  
if(responseCode>=400) O+nEXS\rQ  
{ jkQ*D(;p  
processErrorCode(responseCode); k)i3   
return -2; //-2 represent access is error W6^5YH%  
} jqz ux[6{  
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String sHeader; 
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for(int i=1;;i++) pg6cF  
{ S~<$Hy*kh  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); aJSO4W)P  
//Utility.log(in.readLine()); D+#E-8  
sHeader=httpConnection.getHeaderFieldKey(i); *-#&K\  
if(sHeader!=null) Ij 79~pn  
{ rExnxQ<e  
if(sHeader.equals("Content-Length")) -fM1nH&  
{ b\ X@gq  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ~b(i&DVK  
break; @tF\p  
} \|n- O=}=2  
} gGR"Z]DBk  
else EHSlK5bD,  
break; OP;v bZ  
} _Mi5g_  
} j9m_jv  
catch(IOException e){e.printStackTrace ();} q'+)t7!  
catch(Exception e){e.printStackTrace ();} 7( #:GD  
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Utility.log(nFileLength); ['b}QW@Fx  
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return nFileLength; 0}<|7?  
} 3t.l5m Rg5  
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//保存下载信息（文件指针位置） CVDV)#JA  
private void write_nPos() 36.Z0Z1'F>  
{ ke!?BZx  
try{ 2"COP>  
output = new DataOutputStream(new FileOutputStream(tmpFile)); MO[2~`,Q!  
output.writeInt(nStartPos.length); q~rEq%tk  
for(int i=0;i<nStartPos.length;i++) ]yV!  
{ )"qa kT  
// output.writeLong(nPos); c& <Fr[AK  
output.writeLong(fileSplitterFetch.nStartPos); dLH(D: `  
output.writeLong(fileSplitterFetch.nEndPos); Upx G@b  
} .Q<>-3\K  
output.close(); "x%Htq@  
} nz%DM<0$  
catch(IOException e){e.printStackTrace ();} %J#YM'g  
catch(Exception e){e.printStackTrace ();} G3C~x.(f
 
} "RedK '7g  
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//读取保存的下载信息（文件指针位置） 3N8t`N  
private void read_nPos() zh%#Y_[R  
{ PoNi"Pv  
try{ <<UB ^v m  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 6o^,@~:R  
int nCount = input.readInt(); `34zkPB??  
nStartPos = new long[nCount]; j 'FVz&  
nEndPos = new long[nCount]; ?}qttj  
for(int i=0;i<nStartPos.length;i++) '|ad_M  
{ y~(h>gi,x  
nStartPos = input.readLong(); ?llXd4  
nEndPos = input.readLong(); i|c'Lbre`  
} U1Q:= yD  
input.close(); rUTcpGH  
} eJ,/:=QQ{  
catch(IOException e){e.printStackTrace ();} r=Gks=NX"  
catch(Exception e){e.printStackTrace ();} oL-]3TY~  
} Y=%tn8<  
MvuQz7M#d  
% BVs47g  
private void processErrorCode(int nErrorCode) Y$o<6[7  
{ z__EYh  
System.err.println("Error Code : " + nErrorCode); 4Xgg%@C  
} >1s* at/h  
>/{@C  
9K.V
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//停止文件下载 &]V.S7LC#  
public void siteStop() 7Sf bx~48  
{ H[m:0eF'5  
bStop = true; 2uzW+D6J  
for(int i=0;i<nStartPos.length;i++) f0A{W/0n  
fileSplitterFetch.splitterStop(); 'SO %)B  
:8I9\eet3  
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} Ha(c'\T(\  
} dW_KU}  
//负责部分文件的抓取 j >Ht@Wi  
**FileSplitterFetch.java i
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*/ #TeG-sFJg@  
package NetFox; ]"r&]qx7  
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import java.io.*; ]5mnew  
import java.net.*; Jlri*q"hE  
6wPaJbRtaM  
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public class FileSplitterFetch extends Thread { %fc!2E9|  
ng[Ar`  
8G9s<N}5&u  
String sURL; //File URL H=@}=aPf  
long nStartPos; //File Snippet Start Position [I0:=yJ+  
long nEndPos; //File Snippet End Position dFRsm0T  
int nThreadID; //Thread's ID 6RG)`bu  
boolean bDownOver = false; //Downing is over iyA'#bE-  
boolean bStop = false; //Stop identical VQ"hUX8  
FileAccessI fileAccessI = null; //File Access interface 8H;t_B  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException P !AEf#1  
{ 3("_Z%  
this.sURL = sURL; f6EZ( v  
this.nStartPos = nStart; Mh~q//  
this.nEndPos = nEnd; Olt`:;j-  
nThreadID = id; ) dn(G@5  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 T m,b
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} 2-&k^Gl!:  
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public void run() =w;F<M|Y  
{ :Uz|3gq  
while(nStartPos < nEndPos && !bStop) \O}E7-  
{ ?*2CpM&l  
&?W0mW(  
2I%MAb&1@  
try{ %;cddLQ\xY  
URL url = new URL(sURL); %.vQU @2A  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); .nB0 h  
httpConnection.setRequestProperty("User-Agent","NetFox"); dOa+(f
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String sProperty = "bytes="+nStartPos+"-"; RtGWG*v4]  
httpConnection.setRequestProperty("RANGE",sProperty); u0 P|0\  
Utility.log(sProperty); bmJ5MF]_fG  
_|iSF2f,X  
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InputStream input = httpConnection.getInputStream(); wi;Br[d  
//logResponseHead(httpConnection); 6{
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byte[] b = new byte[1024]; rk&IlAE  
int nRead; MV<^!W  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) wL;lQ&  
{ "*($cQ$v  
nStartPos += fileAccessI.write(b,0,nRead); )n+Lo&C<  
//if(nThreadID == 1) wy yWyf
  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); QXL'^u
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} ,eOB(?Ku
 
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Utility.log("Thread " + nThreadID + " is over!"); %Da8{%{`Pc  
bDownOver = true; kr+D,h01  
//nPos = fileAccessI.write (b,0,nRead); 6tB+JF  
} E;,u2[3  
catch(Exception e){e.printStackTrace ();} $g/S
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} .}&`TU  
} } uO);k5H  
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0vFD3}~>  
//打印回应的头信息 Qi^Z11  
public void logResponseHead(HttpURLConnection con) 7"aN#;&  
{ 4\y/'`xm)6  
for(int i=1;;i++) 2w59^"<,  
{ mlixIW2  
String header=con.getHeaderFieldKey(i); ?a8^1:  
if(header!=null) <d,b'<z s  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); LwrUQ)  
Utility.log(header+" : "+con.getHeaderField(header)); cFaaLUZk  
else Jzj1w}?H  
break; M1 :uJkO.  
} b8~Bazk  
} C3*gn}[  
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d_CKP"TA  
public void splitterStop() 0>C T=(A  
{ n.T&}ZPz\v  
bStop = true; ,#Iu 7di  
} EwuO&q  
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@*OZx9  
} @<&5J7fb  
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~T9/#-e>BF  
/* QFw  +cy  
**FileAccess.java *vflscgt  
*//文件访问(定位，写) _I:~@  
package NetFox; e^d0zl{  
import java.io.*; Ai:BEPKe  
{/"2Vk<H8  
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public class FileAccessI implements Serializable{ 9bP^`\K[N  
q-.,nMUF  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 SNfr"2c'h~  
RandomAccessFile oSavedFile; Px$/ _`H  
long nPos; 0TCBQ~"  
{aY%gk?y#>  
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public FileAccessI() throws IOException ugo.@   
{ b6}H$Sx~  
this("",0); t?q@H8  
} h?rp|uPQ  
'h/CoTk@,  


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public FileAccessI(String sName,long nPos) throws IOException =x!2Ak/)  
{ .uuO>:  
oSavedFile = new RandomAccessFile(sName,"rw"); /s?r`'j[  
this.nPos = nPos; %`O
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oSavedFile.seek(nPos); o}W%I/s  
}  `dFq:8v  
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public synchronized int write(byte[] b,int nStart,int nLen) PK;*u,V  
{ }2<r,  
int n = -1; Anscr  
try{ [K9'<Qnu  
oSavedFile.write(b,nStart,nLen); \n{qsf:  
n = nLen; {. 2k6_1[  
} <Fi%iA  
catch(IOException e) @W vatD V  
{ >=RmGS  
e.printStackTrace (); gg[WlRQK4A  
} p<zSJLN  
p;._HJ(  
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return n; q<\
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} 3AQZRul  
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} ]vgB4~4#LP  
;ado0-VQi'  
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/* LJ*q1 ;<E  
**SiteInfoBean.java 86(I^=  
*/ h!&prY
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package NetFox; {U!8|(  

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GqWB{$J;"  
public class SiteInfoBean { 2W/?q!t  
\]=7!RQ\  
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private String sSiteURL; //Site's URL ,=
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private String sFilePath; //Saved File's Path |p><'Q%*  
private String sFileName; //Saved File's Name dik:4;  
private int nSplitter; //Count of Splited Downloading File b /@#}Gc  
0(mkeIzJt/  
7bk%mQk  
public SiteInfoBean() u:[vaBh91  
{//nSplitter的缺省值为5 V\u>"3BQw  
//default value of nSplitter is 5 X=hYB}}nu  
this("","","",5); BDq%'~/^  
} 9:,V5n=  
&Rx{.9  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) <4_X P.N  
{ >iD )eB  
sSiteURL= sURL; pV20oSJNt  
sFilePath = sPath; T'4z=Z]w  
sFileName = sName; *8#i$w11M  
this.nSplitter = nSpiltter; %1O;fQL  
p$
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_h X]%  
} ;cPy1  
>)spqu]  
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public String getSSiteURL() Sg6"WV{<  
{ V#cqRE3XNi  
return sSiteURL; x
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} ]T;EdK-  
{) Q@c)'  
R,F[XI+=N  
public void setSSiteURL(String value) q>mE< (-M  
{ 0BH_'ZW  
sSiteURL = value; KcK>%%  
} VwOW=4`6  
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public String getSFilePath() c3:,Ab|  
{ UVw~8o9s  
return sFilePath; pcT:]d[1)  
} EX?MA6U  
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public void setSFilePath(String value) blTo5NLX  
{ 1E73i_L  
sFilePath = value; 9[m6Li  
} mf}O-Igte  
t?9v^vFR  
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public String getSFileName() ~.UrL(l=  
{ 4eikLRD,  
return sFileName; 5dB'&8DX  
} <5NF;  
\8<BLmf4U  
$)RNKMZC}A  
public void setSFileName(String value) yto,>Utzg  
{ -C<zF`jO  
sFileName = value; (*oL+ef-C  
} l-ct?T_@  
&_"]5/"(  
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public int getNSplitter() B x (uRj  
{ ?Rj~f{%g  
return nSplitter; hir4ZO%Zt  
} \T<$9aNb  
2I&o69x?  
>y[oP!-|P  
public void setNSplitter(int nCount) 9'{}!-(xR  
{ l2l(_$@3  
nSplitter = nCount; q|8{@EMT  
} #|*F1K  
} Q($Z%1S  
)hk   
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/* G3rj`Sg^c  
**Utility.java JaK}|  
*/ ,t`Kv1  
package NetFox; 0#ClWynjRO  
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public class Utility { |37 g ~  
K91)qI;BD  
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public Utility() nS&3?lx9_  
{ zxf"87
se  
f-5:wM&  
VY)9|JJCO  
} z}{afEb  
#{=;NuP  
//线程睡眠 x-?{E
  
public static void sleep(int nSecond) %-<'QYYP  
{ #/I[Jqf  
try{ ]|sAK%/  
Thread.sleep(nSecond); nv0]05.4  
} t`+'r}=d  
catch(Exception e) h}]fnA  
{ ~M\I;8ne  
e.printStackTrace (); TpHfS]W-P  
} @DZB9DDR  
} CT1ja.\;  
2At
LyN'.  
//日志 %/YcL6o(  
public static void log(String sMsg) [-)r5Dsdq  
{ 6$ Gep  
System.err.println(sMsg); 40|,*wi  
} 1}tbH[  
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S  
5cEcTJL[C  
public static void log(int sMsg) Y_]De3:V0B  
{ 1!.(4gV  
System.err.println(sMsg); kiRa+w:  
} CYKr\DA  
} jiYmb8Q4D  
ZKXo-~=>  
fgBM_c&9T  
/* 1&P<  
**TestMethod.java cKn`/\.H  
*/ 'w14sr%  
package NetFox; 1*dRK6  
Bf$_XG3  
#?XQ7Im  
public class TestMethod { l2&`J_"  
#hlCs  
P9S2?Q  
public TestMethod() |QMhMGjV  
{ ///xx/weblogic60b2_win.exe V=lfl1Ev0J  
try{ *bxzCI7b  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); > ]8a3x  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); "3<da*D1  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Zr-U&9.`  
fileFetch.start(); JR@.R ,rII  
} j~FD{%4N  
catch(Exception e){e.printStackTrace ();} ~j-cS J3  
#Jna6  
HmZ{L +"  
} yB3;  
l/Vo-#  
@]![o %  
public static void main(String[] args) hRq3C1mR  
{ !wWJ^Oz=  
new TestMethod(); ]r-C1bKD`  
} 11,!XD*"  
} efD)S92  
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