http断点续传简单实现（java)

/* -?1R l:rM  
**SiteFileFetch.java L?|
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*/ (j@c946z""  
package NetFox; l/nBin&YGv  
import java.io.*; {`M\}(E  
import java.net.*; e&T-GL  
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public class SiteFileFetch extends Thread { @uV]7d"z(  
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SiteInfoBean siteInfoBean = null; //文件信息Bean !Z\Gv1  
long[] nStartPos; //开始位置 3`{ vx  
long[] nEndPos; //结束位置 J| wk})?  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 FF^h(E
a  
long nFileLength; //文件长度 1Vz^?t:  
boolean bFirst = true; //是否第一次取文件 XM
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boolean bStop = false; //停止标志 ,66(*\xT  
File tmpFile; //文件下载的临时信息 VR
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DataOutputStream output; //输出到文件的输出流 $*N(feAs  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） NV(jp'i~  
public SiteFileFetch(SiteInfoBean bean) throws IOException $]};EI#  
{ SKNHLE}  
siteInfoBean = bean; Rsq EAdZw[  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); E24}?t^|  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); F[jqJzCz  
if(tmpFile.exists ()) k1yqerA  
{ v
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bFirst = false; .L%pWRxA[  
read_nPos(); ,38M6yD  
} QbSLSMoL  
else acUyz2x  
{ ZWS:-]P.  
nStartPos = new long[bean.getNSplitter()]; - uO(qUa#  
nEndPos = new long[bean.getNSplitter()]; *6AqRE  
} 45[,LJaMd  
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} tg 'gR  
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public void run() qj:[NPwaM  
{ keD?#yY  
//获得文件长度 [Rq|;p  
//分割文件 II _CT=  
//实例FileSplitterFetch XA>uCJf  
//启动FileSplitterFetch线程 XI$W  
//等待子线程返回 *Od?>z  
try{ ]:2Ro:4Yv  
if(bFirst) . bUmT!  
{ ~fL`aU&  
nFileLength = getFileSize(); kRwY#  
if(nFileLength == -1) bk=;=K  
{ 2g5 4<G*e  
System.err.println("File Length is not known!"); V,c^Vqy  
} '?.']U,: $  
else if(nFileLength == -2) Ho(}_Q&  
{ I H#CaD  
System.err.println("File is not access!"); *>[q*SF  
} KI*bWe  
else seAEv0YWz  
{ <Pe'&u  
for(int i=0;i<nStartPos.length;i++) #"TYk@whWf  
{ >b0Bvx-  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); />:$"+gKo  
} N:pP@o  
for(int i=0;i<nEndPos.length-1;i++) RZq_}-P,.c  
{ $K\e Pfk  
nEndPos = nStartPos[i+1]; 2{l|<'  
} izl-GitP  
nEndPos[nEndPos.length-1] = nFileLength; Jc5YGj7  
} z.)*/HGJm  
} @QnKaZ8jW  
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e~># M$  
//启动子线程 r+#g  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ]Y->EME:W  
for(int i=0;i<nStartPos.length;i++) :TKx>~`  
{ Uh1UZ r  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ';.y`{/  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), }c=Y<Cdh  
nStartPos,nEndPos,i); \0;w7tdo  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); g co;8e_  
fileSplitterFetch.start(); n,-*$~{  
} Mkt_pr  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), %M8Q6  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); #a|r ^%D  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ~@<o-|#  
nEndPos = " + nFileLength); N^F5J  
// fileSplitterFetch[nPos.length-1].start(); m@D :t5  
kDRxu!/  
@_c&lToj_  
//等待子线程结束 g.;2N9  
//int count = 0; 1_9Ka V  
//是否结束while循环 #ifjQ7(:  
boolean breakWhile = false; wNFx1u^/)  
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]JmE(Y1(1  
while(!bStop) n^qwE
 
{ `)w=@9B)"  
write_nPos(); G'wW-|  
Utility.sleep(500); b rDyjh  
breakWhile = true; ^aJ]|*m  
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*h
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for(int i=0;i<nStartPos.length;i++) xa?auv!  
{ e_rEu'[av  
if(!fileSplitterFetch.bDownOver) /yUKUXi  
{ $6r> Tc](  
breakWhile = false; &:g1*+  
break; e&[~}f?  
} w_QWTD0  
} UIIsgNca  
if(breakWhile) ]*)l_mut7  
break; i"DyXIrk2  
ZN'B@E=p  
# M3d=  
//count++; _|MK0'+f  
//if(count>4) [(8s\>T  
// siteStop(); <5FGL96  
} {VM^K1  
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System.err.println("文件下载结束！"); N0K <zxR  
} -Fop<q\b  
catch(Exception e){e.printStackTrace ();} nS.qK/.s  
} g86^Z%c(k  
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//获得文件长度 |x _jpR  
public long getFileSize() q!5`9u6  
{ bG.`>   
int nFileLength = -1; K^b'<} $|p  
try{ 4Uwcc):f  
URL url = new URL(siteInfoBean.getSSiteURL()); v`7~#Avhz  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ~ `{{Z&  
httpConnection.setRequestProperty("User-Agent","NetFox"); A&-2f]L tl  
,^v_gc  
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int responseCode=httpConnection.getResponseCode(); 4VsttT  
if(responseCode>=400) 'XYjo&w  
{ )7E7K%:b,  
processErrorCode(responseCode); k%N$eO$  
return -2; //-2 represent access is error Vm I Afe  
} Z{F^qwne  
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String sHeader; 0NvicZ7VR  
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for(int i=1;;i++) ] J|#WtS  
{ ^Vc(oa&;  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); /kO%aN  
//Utility.log(in.readLine()); RWJyd=  
sHeader=httpConnection.getHeaderFieldKey(i); 9:E.Iy  
if(sHeader!=null) 4a.8n!sys  
{ \y7\RV>>3b  
if(sHeader.equals("Content-Length")) Oo>U
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{ \x8'K  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Gch3|e  
break; DsHm,dZ  
} x IL]Y7HWM  
}  Qk.[#  
else >ca`0gu  
break; S1i~r+jf  
} @'J[T:e  
} h}o
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catch(IOException e){e.printStackTrace ();} %;GRR (K  
catch(Exception e){e.printStackTrace ();} #Qu|9Q[QH  
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Utility.log(nFileLength); TD!c+${w  
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return nFileLength; 6\QsK96_  
} Vk1 c14i>  
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//保存下载信息（文件指针位置） wu}Z
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private void write_nPos() %=vU Z4  
{ U[ogtfv`
m  
try{ {'?PGk%v
 
output = new DataOutputStream(new FileOutputStream(tmpFile)); 97}l`z;Z  
output.writeInt(nStartPos.length); *44E'Dxv  
for(int i=0;i<nStartPos.length;i++) O%} hNTS"  
{ @< 0c  
// output.writeLong(nPos); S'IQbH
z*  
output.writeLong(fileSplitterFetch.nStartPos); 5~i}!n  
output.writeLong(fileSplitterFetch.nEndPos); 3#`Sk`z<  
} Te>m9Pav  
output.close(); 9N<TJp,q  
} Z =*h9,MY  
catch(IOException e){e.printStackTrace ();} J$yJ2G  
catch(Exception e){e.printStackTrace ();} ?y~"\iP  
} k& ]I;Aq  
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r!p:73L8  
//读取保存的下载信息（文件指针位置） "3Ckc"G@  
private void read_nPos() R\u5!M$::  
{ 0\o5+  
try{ qcBamf  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); *OY Nx4k  
int nCount = input.readInt(); +3R/g@n  
nStartPos = new long[nCount]; _U~~[I  
nEndPos = new long[nCount]; &&sm7F%  
for(int i=0;i<nStartPos.length;i++) bI)%g  
{ lygv#s-T  
nStartPos = input.readLong(); q9$K.=_5  
nEndPos = input.readLong(); ,e*WJh8k[  
} AIM
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input.close(); 'W p~8}i@  
} mbIHzzW>  
catch(IOException e){e.printStackTrace ();} A] f^9F@  
catch(Exception e){e.printStackTrace ();} %^;rYn3  
} *adwCiB  
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private void processErrorCode(int nErrorCode) h,i=Y+1  
{ 2)|G%f_lS  
System.err.println("Error Code : " + nErrorCode); Okd7ua-f  
} @u-CR8^  
gt(!I^LHYc  
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//停止文件下载 .fNLhyd  
public void siteStop() Ot~buf'|  
{ %?O$xQ.<  
bStop = true; {jEEAH)  
for(int i=0;i<nStartPos.length;i++) &f/"ir[8i  
fileSplitterFetch.splitterStop(); wQOIUvd  
OT3
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} #nS crs@  
} 9f3rMPVh(  
//负责部分文件的抓取 +!-U+W  
**FileSplitterFetch.java -EWC3,3  
*/ 4FJA+  
package NetFox; )H*BTfmt  
ded:yho  
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import java.io.*; O|&SL03Z8  
import java.net.*; aydf# [F  
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public class FileSplitterFetch extends Thread { ua%j
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String sURL; //File URL cx*$GaMk  
long nStartPos; //File Snippet Start Position 5Ln !>,  
long nEndPos; //File Snippet End Position qo:t"x^  
int nThreadID; //Thread's ID _qSVYVJ u  
boolean bDownOver = false; //Downing is over XlxM
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boolean bStop = false; //Stop identical wF{M"$am  
FileAccessI fileAccessI = null; //File Access interface LcmZ"M6  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException -)!;45  
{ #9]O92t2UV  
this.sURL = sURL; <*db%{  
this.nStartPos = nStart; F<Z13]|  
this.nEndPos = nEnd; idY Xv)R  
nThreadID = id; +-MieiKv  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 _>Oc>.MB  
} qGECw#  
D4U<Rn6N_5  
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public void run() wl%I(Cw{]  
{ B3&ETi5NTU  
while(nStartPos < nEndPos && !bStop) d@+u&xrd  
{ X->` ~-aj  
dwUs[v  
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try{ Q6%Pp_$k  
URL url = new URL(sURL); X/A(8rvCr  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); fv
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httpConnection.setRequestProperty("User-Agent","NetFox"); qXB5wDJg  
String sProperty = "bytes="+nStartPos+"-"; e+wIN
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httpConnection.setRequestProperty("RANGE",sProperty); _/h<4G6A  
Utility.log(sProperty); a} :2lL%  
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InputStream input = httpConnection.getInputStream(); UZ7ukn-  
//logResponseHead(httpConnection); ryt`yO  
/3qKsv#  
$NwPGy?%  
byte[] b = new byte[1024]; !~ZAm3GwL  
int nRead; 3U[:N &Jb  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) | =tGrHL  
{ j%fi*2uX  
nStartPos += fileAccessI.write(b,0,nRead); UkM#uKr:  
//if(nThreadID == 1) *\$ko)x?c  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ffem7eQ  
} [g$
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9]^NAlno  
5_4=(?<  
Utility.log("Thread " + nThreadID + " is over!"); v)LSH;<  
bDownOver = true; O\}w&BE:h  
//nPos = fileAccessI.write (b,0,nRead); g ~>nT>6  
} P+Sgbtc  
catch(Exception e){e.printStackTrace ();} lO8GnkLE  
} H8qWY"<Vd  
} )Xice=x9  
:Oi}X7\  
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//打印回应的头信息 X-cP'"  
public void logResponseHead(HttpURLConnection con) `/o|1vv@_  
{ %H=^U
8WB  
for(int i=1;;i++) M8f[ck  
{ \}; 4rm}V  
String header=con.getHeaderFieldKey(i); |pR'#M4j4A  
if(header!=null) !s[
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//responseHeaders.put(header,httpConnection.getHeaderField(header)); 8,]wOxwqi  
Utility.log(header+" : "+con.getHeaderField(header)); FOS*X  
else /7K7o8g  
break; *xDV8iu_  
} GCp90  
} d"}lh:L9  
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public void splitterStop() -5,+gakSk  
{ sJm v{wM  
bStop = true; 6Bn
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} Dx.hM[  
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8FgF6ip  
} r ['zp=9  

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/* s"X0Jx}
 
**FileAccess.java X92I==-w  
*//文件访问(定位，写) nC#SnyUO  
package NetFox; {"\pMY'7  
import java.io.*; X^d}eWP`I  
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public class FileAccessI implements Serializable{ PH=O>a`a_O  
oX?~  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 gg$:U  
RandomAccessFile oSavedFile; *)Pb-c
 
long nPos; VoNk.h"T  
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public FileAccessI() throws IOException 1N+ju"2R  
{ fP{IW`t}]  
this("",0); bl4I4RB  
} $A>]lLo0  
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public FileAccessI(String sName,long nPos) throws IOException 7h\U}!  
{ QX+&[G!DZH  
oSavedFile = new RandomAccessFile(sName,"rw"); [B%:!Q)@  
this.nPos = nPos; {N@tJ,Fh{  
oSavedFile.seek(nPos); D1cnf"y^  
} ~oeX0l>F  
6tup^Rlo;$  
#x(3>}  
public synchronized int write(byte[] b,int nStart,int nLen) ]9hhAT44  
{ y1Y  
int n = -1; ccgV-'IG9  
try{ NeniQeR  
oSavedFile.write(b,nStart,nLen);
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n = nLen; I<hMS6$<LE  
} 7:wf!\@I  
catch(IOException e) 3s_$.  
{ |7b@w;q,D  
e.printStackTrace (); OdtS5:L  
} y@dTdR2Wc  
9+:<RFJ  
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return n; Zu/1:8x  
} Z xR  
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8%^W<.Y  
} r&nEM6  
6o]>lQ}  
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/* iG=XRctgj)  
**SiteInfoBean.java }dG>_/3  
*/ 1yjP`N  
package NetFox; DK(8Ml:k  
Ikgia:/-Z  
i/F].Sag  
public class SiteInfoBean { (2r808^2  
\7 }{\hY-  
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private String sSiteURL; //Site's URL 3 /LW6W|  
private String sFilePath; //Saved File's Path 6?= ^8  
private String sFileName; //Saved File's Name tflUy\H>  
private int nSplitter; //Count of Splited Downloading File 4_o+gG%HaM  
49dN~k=  
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public SiteInfoBean() zc!q a"4yM  
{//nSplitter的缺省值为5 yz_xWx#9  
//default value of nSplitter is 5 jW]Fx:mQi  
this("","","",5); ;ZR^9%+y9  
} 0]l9x}  
BDPF>lPf<  
vPx#TXY=b}  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ;f2<vp;U  
{ 
CV*  
sSiteURL= sURL; 2yndna-  
sFilePath = sPath; $ZnVs@:S  
sFileName = sName; G/V0Yn""  
this.nSplitter = nSpiltter; C<N7zMwT  
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} fl<j]{*v  
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public String getSSiteURL() eLk:
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{ }~! D]/B  
return sSiteURL; vf['$um  
} K2-nP2Go?  
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public void setSSiteURL(String value) ,~7+r#q7  
{ .KF(_ 92  
sSiteURL = value; 'z">4{5  
} "IJcKoB  
~JohcU}d  
]H=P(Z-  
public String getSFilePath() \-I)dMm[  
{ ;;n=(cM|z  
return sFilePath; _H$Z}2g<z  
} ~D!Y] SK  
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public void setSFilePath(String value) *jo1?  
{ )iCg,?SSw=  
sFilePath = value; V-zF'KI[  
} :*)b<:4  
k1;Jkq~  
[N1[khY`  
public String getSFileName() UQCond+K  
{ WvWZzlw  
return sFileName; a,\GOy(q{  
} +(vL~  
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vQDkZ  
public void setSFileName(String value) u9%AK g}~  
{ &Ef6'  
sFileName = value; |~YhN'OJ  
} t)b /c:ql  
6>-Gi  
+g8uV hC  
public int getNSplitter() L'}^Av_+  
{ Oa-~}hN  
return nSplitter; [
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} B-aJn8>/  
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public void setNSplitter(int nCount) 4mF=A$Q_/  
{ ,4kipJ!,yK  
nSplitter = nCount; QlWkK.<Z3_  
} ?+y# t?
 
} pt8#cU
\  
7'TXR[  
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/* $ iU~p  
**Utility.java ;q" ,Bs  
*/ > V%3w7  
package NetFox; v
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public class Utility { EO\@#",a  
Fs1ms)  
Gm'Ch}E  
public Utility() 9Q*zf@w  
{ Pna2IB+  
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yy$7{9!  
} ekO*(vQ~  
-Khb  
//线程睡眠 'C\knQ  
public static void sleep(int nSecond) LQ=Fck~[r  
{ i+B
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try{ -xc'P,`  
Thread.sleep(nSecond); Q4&<RWbT^  
} ^W
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catch(Exception e) |Xa|%f  
{ K6z-brvw"  
e.printStackTrace (); VWcR@/3  
} 1F }mlyS  
} O,!4 W\s  
6'vt '9  
//日志 ?kM53zbT#  
public static void log(String sMsg) `PvGfmYOl  
{ T
1pMe{  
System.err.println(sMsg); }8&L?B;90  
} O8S"B6?$~'  
j8#B  
>l|dLyiae  
public static void log(int sMsg) K>fY9`Whm  
{ @ei:/~y3  
System.err.println(sMsg);
+Ek('KOF  
} vt-53fa|  
} [:\8Ug8  
.6#Y-iJqc  
;l'kPUv([  
/* ,R;wk=k  
**TestMethod.java OQZ\/~o 5  
*/ EL-1o02-  
package NetFox; IEJ
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[!E~pW%|n  
public class TestMethod { ;yK:.Vg  
Z]Iyj 97  
Gn%gSH/  
public TestMethod() [sH[bmLR  
{ ///xx/weblogic60b2_win.exe JK9}Kb};  
try{ {BKr/) H  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); :ift{XR'  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); gAgP("  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Gr?[s'Ze  
fileFetch.start(); (~FLG I  
} j(maj  
catch(Exception e){e.printStackTrace ();} +R?d6IjH  
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)51
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} 8y, ]>n  
bbO1`b-  
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public static void main(String[] args) 4?{e?5)  
{ 7T3ub3\  
new TestMethod(); +#!! 'XP  
} 5=--+8[ bV  
} lj!f\C}d  
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