http断点续传简单实现（java)

/* 1\y@E  
**SiteFileFetch.java XC2FF&B&  
*/ cv]BV>=E  
package NetFox; M
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import java.io.*; Jr]gEBX  
import java.net.*; *!w25t  
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public class SiteFileFetch extends Thread { *,&S',S-  
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SiteInfoBean siteInfoBean = null; //文件信息Bean x}|+sS,g  
long[] nStartPos; //开始位置 I>aGp|4  
long[] nEndPos; //结束位置 +j.qZ8  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 .;g}%C  
long nFileLength; //文件长度 Lc%xc`n8B  
boolean bFirst = true; //是否第一次取文件 e^8BV;+c  
boolean bStop = false; //停止标志 ?2ItTrlB  
File tmpFile; //文件下载的临时信息 )b9_C O}  
DataOutputStream output; //输出到文件的输出流 r8,om^N6  
@D]lgq[  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） yPN+W8}f  
public SiteFileFetch(SiteInfoBean bean) throws IOException "Vy WT  
{ l sr?b  
siteInfoBean = bean; H{%H^t>  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); T pD;  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); *{|$FQnR>(  
if(tmpFile.exists ()) oqYt/4^Q  
{ ceG&,a$\  
bFirst = false; A?r^V2+j  
read_nPos(); *gDl~qNRoS  
} NH4?q!'G  
else SO_>c+Dw  
{ qe%
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nStartPos = new long[bean.getNSplitter()]; #Kl}= 1 4  
nEndPos = new long[bean.getNSplitter()]; [,b)YjO~Xd  
} #1gO?N(<=  
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} W-m"@<Z  
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public void run() `XgFga)  
{ B`1kGEx .  
//获得文件长度 En\Z#0,V  
//分割文件 8kH<$9  
//实例FileSplitterFetch 3+V#[JBJv  
//启动FileSplitterFetch线程 `[Sl1saZ$S  
//等待子线程返回 (A4&k{C_  
try{ e2wvc/gG6  
if(bFirst) F&az":  
{ h/?6=D{  
nFileLength = getFileSize(); SY T$3|a  
if(nFileLength == -1) ;MPKJS68@  
{ 9go))&`PJL  
System.err.println("File Length is not known!"); oj@g2H5P  
} CmnHh~%  
else if(nFileLength == -2)
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{ ;7j,MbU  
System.err.println("File is not access!"); *|KVN&#  
} x<>YUw8`  
else M4:s;@qZ.  
{ l!@ 1u^v2  
for(int i=0;i<nStartPos.length;i++) (O0byu}  
{ E}YIWTX  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); hZU1O  
} kceyuD$3G  
for(int i=0;i<nEndPos.length-1;i++) ]r959+\$  
{ 8UM0vNk  
nEndPos = nStartPos[i+1]; nNQ-
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} ShGp^xVj  
nEndPos[nEndPos.length-1] = nFileLength; ) EXJ   
} ]0-<>  
} 4Jykos2  
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//启动子线程 x<F$aXOS  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; iRve)  
for(int i=0;i<nStartPos.length;i++) ix*muVBj.  
{ tvpN/p  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 0T9.M(  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), " "%#cDR  
nStartPos,nEndPos,i); LGVlc@0'  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); |,sMST%  
fileSplitterFetch.start(); `D2Mss$!  
} ArXl=s';s4  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), t9` Ed>a  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Ct!S T
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// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", !*vBW/  
nEndPos = " + nFileLength); vD26;S.y[a  
// fileSplitterFetch[nPos.length-1].start(); "~\*If  
N RSU+D-z  
PeNF+5s/K  
//等待子线程结束 [h-norB((  
//int count = 0; OZOb1D  
//是否结束while循环 niWx^gKb$  
boolean breakWhile = false; Pm?B 9S  
T*+A.G@L"  
A3q*$.[  
while(!bStop) ch })ivFP[  
{ >nM%p4E  
write_nPos(); -nR\,+N  
Utility.sleep(500); 28UVDG1?  
breakWhile = true; A*i_|]Q  
 S^j,f'2  
jQ$BPEG&X  
for(int i=0;i<nStartPos.length;i++) zP nC=h|g  
{ PGX+p+wB  
if(!fileSplitterFetch.bDownOver) Uw <{i  
{ M-Sv1ZLh  
breakWhile = false; fM^<+o@  
break; '5rUe\k  
} 9o_-=>(  
} 7'eh)[T  
if(breakWhile) u-.L^!k  
break; ;k}H(QI  
~L'nzquF  
f#OQ (WTJE  
//count++; ZqK]jT6V/X  
//if(count>4) i@,]Z~]  
// siteStop(); T4GW1NP  
} E474l  
( 3;`bvYH"  
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System.err.println("文件下载结束！"); =x H~ww (D  
} 6N3@!xtpi  
catch(Exception e){e.printStackTrace ();} *Hu
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} *s\sa+2al  
/80YZ   
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//获得文件长度 3dm'xetM  
public long getFileSize() Ef,Cd[]b  
{ ~ 5"J(  
int nFileLength = -1; [hHG.  
try{ /s`;9)G]9  
URL url = new URL(siteInfoBean.getSSiteURL()); %g w{[ /[A  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); g^j7@dum  
httpConnection.setRequestProperty("User-Agent","NetFox"); Funj!x'uE  
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int responseCode=httpConnection.getResponseCode(); aYVDp{_  
if(responseCode>=400) eqhAus?)  
{ o](.368+4  
processErrorCode(responseCode); Euu ,mleM  
return -2; //-2 represent access is error `%y5\!X  
} y<M]dd$  
:hP58 }Q$  
q%S8\bt  
String sHeader; !<r8~A3!(  
[H^ X"D  
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for(int i=1;;i++) d?7BxYa
a  
{ r/Dd&x  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); (}~ucI<~  
//Utility.log(in.readLine()); x6e+7"#~  
sHeader=httpConnection.getHeaderFieldKey(i); {^m5#f 0"  
if(sHeader!=null) P(;Mb{  
{ ]o*$h$?s  
if(sHeader.equals("Content-Length")) v{koKQ'Y()  
{ CZ tiWZ  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); M/B/b<['  
break; &+- e  
} v#Upw\!  
} 2AK}D%jfc  
else #r}uin*jD  
break; =v0~[E4  
} m6MaX}&zv  
} S@A<6  
catch(IOException e){e.printStackTrace ();} usH%dzKK  
catch(Exception e){e.printStackTrace ();} ]l&'k23~p  
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Utility.log(nFileLength); }Vl^EAR  
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return nFileLength; @p]UvqtB@  
} 8\_*1h40s  
qTy v.#{y  
KPggDKS  
//保存下载信息（文件指针位置） +WLD  
private void write_nPos() XhA4:t  
{ Q>%E
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try{ u){S$</  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ~U%j{8uH  
output.writeInt(nStartPos.length); `]{Psc6_=  
for(int i=0;i<nStartPos.length;i++) ,`)OEI|1d  
{ kfK[u/<i  
// output.writeLong(nPos); (9
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output.writeLong(fileSplitterFetch.nStartPos); 4(|yD;  
output.writeLong(fileSplitterFetch.nEndPos); 0BDS_Rx  
} pVz*ZQ[]  
output.close(); PWG;&ma  
} 7LdzZS0OM  
catch(IOException e){e.printStackTrace ();} fTgbF{?xh  
catch(Exception e){e.printStackTrace ();} }4KW@L[g  
} '!@A}&]  
8Fx]koP.  
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//读取保存的下载信息（文件指针位置） /.@x 4cdS  
private void read_nPos() . s-5N\  
{ ^O \q3HA_4  
try{ :D4];d>1  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); T 9MzUV&  
int nCount = input.readInt(); UM\}aq=,  
nStartPos = new long[nCount]; #JFYws  
nEndPos = new long[nCount]; 'M-)Os"  
for(int i=0;i<nStartPos.length;i++) )Y[/!  
{ l7~Pa0qD  
nStartPos = input.readLong(); }5hZo%w[n  
nEndPos = input.readLong(); 6>u
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} 453 }S  
input.close(); kQ[Jo%YT?E  
} |Eu*P  
catch(IOException e){e.printStackTrace ();} mtX31M4  
catch(Exception e){e.printStackTrace ();} Gw`/.0
 
} tvCcyD%w  
-R8/`M8GbD  
//tT8HX  
private void processErrorCode(int nErrorCode) -#OwJ*-U  
{ b=G4MZQ  
System.err.println("Error Code : " + nErrorCode); b~9`]+  
} mF~ys{"t  
q;No"_aAd  
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//停止文件下载 QH:>jmC{1h  
public void siteStop() cqjl5UB  
{ 6kR -rA  
bStop = true; Rv,Mu3\~#c  
for(int i=0;i<nStartPos.length;i++) 1q`k}KMy  
fileSplitterFetch.splitterStop(); )*W=GY*  
RUqO!s~#rY  
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} *?p ^6vO  
} $r):d  
//负责部分文件的抓取 Lz?*B$h  
**FileSplitterFetch.java 6"%@L{UQ  
*/ Z,SY N?@  
package NetFox; z6 a,0&;-L  
bl`D+/V   
iel-<(~  
import java.io.*; 6N?#b66  
import java.net.*; 1y~L8!:L  
zF?31\GOX  
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public class FileSplitterFetch extends Thread { @o60c  
?0uOR*y'  
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String sURL; //File URL ovbEmb  
long nStartPos; //File Snippet Start Position +\srZ<67  
long nEndPos; //File Snippet End Position 
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int nThreadID; //Thread's ID L7<+LA)s0  
boolean bDownOver = false; //Downing is over r(]98a]o~  
boolean bStop = false; //Stop identical _tA7=*@8  
FileAccessI fileAccessI = null; //File Access interface %6N)G!P  
S7Znz@  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException drbe#FObX  
{ "A]?M<R  
this.sURL = sURL; ovB
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this.nStartPos = nStart; Y}S.37|+^  
this.nEndPos = nEnd; f&f`J/(  
nThreadID = id; 9QC< E|  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 D(!;V KH  
} hRa\1Jt>a  
*^uGvJXF  
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public void run() @K7ebYr?  
{ <o~t$TH  
while(nStartPos < nEndPos && !bStop) &{BBxv)y  
{ ?THa5%8f  
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try{ KM5jl9Vv  
URL url = new URL(sURL); y2GQN:X  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Qg[heND  
httpConnection.setRequestProperty("User-Agent","NetFox"); ?vMK'"  
String sProperty = "bytes="+nStartPos+"-"; /q T E  
httpConnection.setRequestProperty("RANGE",sProperty); b-2pzcK{#  
Utility.log(sProperty); hr%U>U9F  
)sRN
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(v]P<3%  
InputStream input = httpConnection.getInputStream(); uW ) \,  
//logResponseHead(httpConnection); Ywmyr[Uh'  
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byte[] b = new byte[1024]; x!O
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int nRead; EG%I1F%  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Y
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{ PL9<*.U"=  
nStartPos += fileAccessI.write(b,0,nRead); ZTr:xX{R6  
//if(nThreadID == 1) Wa(W&]  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); c$.
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} 9z+vFk`  
0,:iE\
 
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Utility.log("Thread " + nThreadID + " is over!"); +I*k0"gj6  
bDownOver = true; h]<GTWj  
//nPos = fileAccessI.write (b,0,nRead); _cR6ik zW(  
} eR7qE) h  
catch(Exception e){e.printStackTrace ();} ?0 HR(N(z!  
} m\_+)eI|  
} L7X7Zt8%  
0K&_D)  
>ze>Xr'm5=  
//打印回应的头信息 BHEs+e0  
public void logResponseHead(HttpURLConnection con) xT:qe  
{ ;&RUE  
for(int i=1;;i++) pi|\0lH6W  
{ t#a.}Jl  
String header=con.getHeaderFieldKey(i); cZ6?P`X  
if(header!=null) b*cW<vX}~  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); :b.3CL\.6  
Utility.log(header+" : "+con.getHeaderField(header)); a:=q8Qy  
else $[)6H7!U)  
break; ThjUiuWe  
}
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} _2wAaJvA  
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public void splitterStop() MKV=m8G=  
{ C_6GOpl  
bStop = true; cR,'o'V/  
} 65'`uuPx  
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} eVJ= .?r  
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c'"#q)  
/* ,jAx%]@,I  
**FileAccess.java !>CE(;E>z  
*//文件访问(定位，写) V+Y|4Y&  
package NetFox; R 4DM_u  
import java.io.*; XPar_8I  
d^ 2u}^kG  
uCY(:;[<  
public class FileAccessI implements Serializable{ W/#KX}4  
Kl4isGcr]  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 7h(HG?2Y  
RandomAccessFile oSavedFile; ) ~ l\  
long nPos; VI(RT-S6  
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public FileAccessI() throws IOException aeEw#  
{ OG0r4^6Ly  
this("",0); 7xX;MB&  
} `Af{H/qiI  
/p[|DJoM  
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public FileAccessI(String sName,long nPos) throws IOException AQE eIFH  
{ Y'tqm&}  
oSavedFile = new RandomAccessFile(sName,"rw"); 6"BtfQ")  
this.nPos = nPos; Q&oC]u(="&  
oSavedFile.seek(nPos); j9{O0[v  
} ^>3tYg&7  
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public synchronized int write(byte[] b,int nStart,int nLen) x, G6\QmA  
{ i}.{m Et  
int n = -1; qzuQq94k  
try{ pWWL{@J  
oSavedFile.write(b,nStart,nLen); &{X{36  
n = nLen; Yh}zt H  
} uPa/,"p  
catch(IOException e) F?*Dr  
{ h$E\2lsE  
e.printStackTrace (); \4[c}l  
} )B-MPuB  
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return n; UN cYu9[  
} xI=}z
 
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} P5'iYahCq_  
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/* b:N^Fe
 
**SiteInfoBean.java ioE66-n  
*/ +)/Rql(lY  
package NetFox; 08TaFzP81  
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public class SiteInfoBean { `_
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private String sSiteURL; //Site's URL W?*Xy6",JF  
private String sFilePath; //Saved File's Path  ET >S  
private String sFileName; //Saved File's Name [@,OG-"&  
private int nSplitter; //Count of Splited Downloading File />dB%*  
r1[E{Tpz  
RB S[*D  
public SiteInfoBean() ,pQ'w7  
{//nSplitter的缺省值为5 3::3r}g  
//default value of nSplitter is 5 D

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this("","","",5); h(C#\{V  
} :zizca4  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) viW~'}^k7  
{ "D ts*  
sSiteURL= sURL; Wrf^O2  
sFilePath = sPath; _&k'j)rg  
sFileName = sName; 7Y-FUZ.`>  
this.nSplitter = nSpiltter; U^E  
p9FA_(`^  
uE,i-g0$Id  
} blKDQ~T2  
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public String getSSiteURL() Nz(c"3T;  
{ VxUvvJ{-v  
return sSiteURL; Uv @!i0W  
} .4S^nP  
_aXP ;kFMi  
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public void setSSiteURL(String value) KKeb ioW  
{ SY!`a:It  
sSiteURL = value; 4_6W s$x  
} C:'WX*W  
]p4`7@@)*  
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public String getSFilePath() &^CL]&/  
{ 2.fyP"P L  
return sFilePath; T[Z <bW~0  
} 2]of SdM  
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public void setSFilePath(String value) ?G~/{m.  
{ WrE-Zti  
sFilePath = value; W%Y.SP$Y  
} H{ n>KZ]\  
.c=$ bQ>^  
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public String getSFileName() E)&NP}k-P  
{ !#,-  
return sFileName; 8!`7-  
} 'Yaf\Hp  
&X#x9|=&O  
[M7iJcwt  
public void setSFileName(String value)  |0C|$2  
{ Z`-)1!  
sFileName = value; ^F0k2
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} 2- Npw%;  
x*loACee.  
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public int getNSplitter() OBKC$e6I  
{ hQg,#r(JE4  
return nSplitter; C&gOA8nf  
} eeI9[lTw  
|kBg8)
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public void setNSplitter(int nCount) 2-"Lxe65f  
{ |!4BWt  
nSplitter = nCount; s]nGpA[!  
} C;58z5*,  
} <eud#v  
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/* 7})!>p )  
**Utility.java )9A<fwpN  
*/ V',m $   
package NetFox; ^td!g1"<  
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public class Utility { 0]:*v?  
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public Utility() J]=aI>Ow  
{ 3%vx'1h[  
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} 1eE]4Z4Q  
JhMrm%  
//线程睡眠 9AVK_   
public static void sleep(int nSecond) $.r}g\43P  
{ X_0{*!v8  
try{ oSu|Yn  
Thread.sleep(nSecond); y7;XOPm  
} AXNszS%4  
catch(Exception e) a!^-~pH:  
{ }OX>(  
e.printStackTrace (); G(7\
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} o3TBRn,  
} XqE55Jclp  
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//日志 eBSn1n  
public static void log(String sMsg) 6,g5To#vw  
{ r$3~bS$]  
System.err.println(sMsg); T,xVQ4J?  
} fr,CH{Uq  
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public static void log(int sMsg) ys.!S.k+  
{ :nbW.B3GV  
System.err.println(sMsg); $E4O^0%/p  
} X('Q;^`  
} `3
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)K\k6HC.  
/* 6&OonYsP  
**TestMethod.java uc"[qT(X  
*/ H z< M  
package NetFox; Skk3M?  
HhQPgjZ/  
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public class TestMethod { Op$J"R  
*]>OCGsr  
[hv3o0".  
public TestMethod() n_xQSVI0F  
{ ///xx/weblogic60b2_win.exe .2(@jx,[  
try{ <-oRhi4  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5);
(W}i287  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); !g8.8(/t)  
SiteFileFetch fileFetch = new SiteFileFetch(bean); d'g{K]=tF  
fileFetch.start(); 0|DG\&?  
} D)/XP  
catch(Exception e){e.printStackTrace ();} z5o9\.y({  
Fb<\(#t  
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} w_z^5\u0  
a,0o{*(u$  
?w5nKpG#RI  
public static void main(String[] args) )Ido|!]0d  
{ )H37a  
new TestMethod(); z7l;|T  
} `aWwF} +Y  
} 2h? r![  
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