http断点续传简单实现（java)

/* n
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**SiteFileFetch.java {t9U]hX%A[  
*/ )Dv"seH.  
package NetFox; 6/GhQ/T%D  
import java.io.*; '2%hc\P6P  
import java.net.*; 1pc|]9B  
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public class SiteFileFetch extends Thread { <1hwXo  
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SiteInfoBean siteInfoBean = null; //文件信息Bean <,LeFy\zW  
long[] nStartPos; //开始位置 4=1lyw  
long[] nEndPos; //结束位置 u52@{@Ad  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 s cn!,  
long nFileLength; //文件长度 *yt/ Dj  
boolean bFirst = true; //是否第一次取文件 `RjcJ?r  
boolean bStop = false; //停止标志 H-I*;  
File tmpFile; //文件下载的临时信息 N'^ 0:zK:  
DataOutputStream output; //输出到文件的输出流 [V1gj9t=,  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） S;CT:kG6Y{  
public SiteFileFetch(SiteInfoBean bean) throws IOException ~kYF/B2*  
{ smWA~Aq  
siteInfoBean = bean; [T
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//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); [t ^|l?  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); /0(4wZe~?  
if(tmpFile.exists ()) XbHcd8N T  
{ AjZT- Q0L  
bFirst = false; IPJs$PtKok  
read_nPos(); 0V1kZ.  
} J H$  
else 5m_@s?P[  
{ oE5+   
nStartPos = new long[bean.getNSplitter()]; #?aR,@n  
nEndPos = new long[bean.getNSplitter()]; fF>H7  
} qT}&XK`Q^  
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} J,IOp-  
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public void run() gAR];(*  
{ mTcLocx  
//获得文件长度
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//分割文件 <KJ18/  
//实例FileSplitterFetch iPHMyxT+S  
//启动FileSplitterFetch线程 J
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//等待子线程返回 EQ7cK63  
try{ uV;Z  
if(bFirst) `UeF3~)>E  
{ O" T1=4  
nFileLength = getFileSize(); _I@dt6oF  
if(nFileLength == -1) +LrW#K;  
{ h#;yA"j1&  
System.err.println("File Length is not known!"); K5k,47"  
} ukri7 n
*  
else if(nFileLength == -2) @89mj{  
{ /ZD/!YD&R  
System.err.println("File is not access!"); ay4|N!ExO  
} ^B5Hjf9  
else QAX+oy  
{ 1)k))w9  
for(int i=0;i<nStartPos.length;i++) uE/qraA  
{ g|2D(J  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); #
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}  6W3}6p  
for(int i=0;i<nEndPos.length-1;i++) 3fBq~Q  
{ J|3CG;+  
nEndPos = nStartPos[i+1]; bEPXNN  
} s'/ug  
nEndPos[nEndPos.length-1] = nFileLength; LZ^sc  
} Av/|={i  
} d'DS7F(c{  
I|BLAm6j  
783a Z8  
//启动子线程 ,/Xxj\i  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length];  E?%k  
for(int i=0;i<nStartPos.length;i++) SR8[ 7MU  
{ F[9IHT6{  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), SUx\
qz)  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ab 2V.S  
nStartPos,nEndPos,i); mQ1QJ_;  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); d{DlW |_  
fileSplitterFetch.start(); WukCE  
} s;$ eq);  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), !a1jc_  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ]%NCKOM  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ]>x674H  
nEndPos = " + nFileLength); 1q/z&@+B  
// fileSplitterFetch[nPos.length-1].start(); <f:b%Pm7  
AvH/Q_-b  
ZP?](RV>xg  
//等待子线程结束 ][TS|\\  
//int count = 0; hu6)GOZbv  
//是否结束while循环 |[xi"E\  
boolean breakWhile = false; _Z9I')  
8f#YUK sW=  
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while(!bStop) nEs l  
{ Vd|/]Zj  
write_nPos(); -BNW\]}  
Utility.sleep(500); E6BW&Xp  
breakWhile = true; vUj7rDT|  
'O2{0  
];oED?I  
for(int i=0;i<nStartPos.length;i++) w/Ia`Tx$  
{ <sd Qvlx$-  
if(!fileSplitterFetch.bDownOver) XMuZ
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{ im*XS@Uj  
breakWhile = false; 9/^4W.  
break; Ip?Ueaei  
} <o p !dS  
}
'L=g(  
if(breakWhile) E-n!3RQ(w  
break; >oLM2VJ  
c-`&e-~XKL  
Br-
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//count++; >iaZGXje  
//if(count>4) hLO nX<%a  
// siteStop(); ]_5C5m  
} |h8C}P&Z  
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System.err.println("文件下载结束！"); E&]S No<  
} :90DS_4  
catch(Exception e){e.printStackTrace ();} $g5pKk
  
} *:)#'cenI  
gl00$}
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qCIZW  
//获得文件长度 LvE|K&R|  
public long getFileSize() )]rGGN
F*  
{ Bxz{rR0XV  
int nFileLength = -1; -08Ys c  
try{ %!LrC!6P4  
URL url = new URL(siteInfoBean.getSSiteURL()); ]ujH7T  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 4AUY8Pxp  
httpConnection.setRequestProperty("User-Agent","NetFox"); 0p&:9|'z  
])0&el3-  
@4hxGk=
 
int responseCode=httpConnection.getResponseCode(); *$uKg zv3  
if(responseCode>=400) ^8E/I]-  
{ P0UMMn\-#  
processErrorCode(responseCode); awo=%vJ&  
return -2; //-2 represent access is error b(K.p?bt  
} mrk Q20D  
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String sHeader; SlsMMD  
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for(int i=1;;i++) vk.Y2 :  
{ #P18vK5  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); vy6NH5Q  
//Utility.log(in.readLine()); >0B[  
sHeader=httpConnection.getHeaderFieldKey(i); p8o%H-Xk
 
if(sHeader!=null) }?8K
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{ R3%T}^;f  
if(sHeader.equals("Content-Length")) $ 'HiNP {c  
{ {h|3P/?7  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ;%Jp@'46  
break; QMHeU>  
} m,qU})  
} 69\0$O  
else !=I:Uc-Y  
break; T3wR0,  
} ,tmo6D62  
} I0GL/a4s  
catch(IOException e){e.printStackTrace ();} B% BO  
catch(Exception e){e.printStackTrace ();} kRZ(
 
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Utility.log(nFileLength); Qa(u+  
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return nFileLength; Cg8{NNeD  
}
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//保存下载信息（文件指针位置） .|x0du|  
private void write_nPos() b<Pjmb+  
{ sRt|G  
try{ D)4p8-=t  
output = new DataOutputStream(new FileOutputStream(tmpFile)); yu3EPT!~  
output.writeInt(nStartPos.length); v;jrAND  
for(int i=0;i<nStartPos.length;i++) u&r@@p.  
{ 5as';1^P&*  
// output.writeLong(nPos); HwM:bY N  
output.writeLong(fileSplitterFetch.nStartPos); >/ HC{.k  
output.writeLong(fileSplitterFetch.nEndPos); RSzp-sKB  
} E8#y
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output.close(); v>7tJ[s  
} Pr@EpO  
catch(IOException e){e.printStackTrace ();} e7pN9tXGf  
catch(Exception e){e.printStackTrace ();} B_c(3n-"  
} 9`-ofwr'|  
]^ZC^z;H  
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//读取保存的下载信息（文件指针位置） =@w};e#D  
private void read_nPos() `[57U,v  
{ ;,@3bu>r  
try{ ]-L/Of6F)|  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); B~yD4^  
int nCount = input.readInt(); ]wdudvS@6r  
nStartPos = new long[nCount]; C'*1
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nEndPos = new long[nCount]; #q(BR{A>t  
for(int i=0;i<nStartPos.length;i++) SS(jjpe&,  
{ 75I*&Wl  
nStartPos = input.readLong(); {%b>/r  
nEndPos = input.readLong(); umI#P,%[  
} QO%>RG  
input.close(); [sACPn$f  
} {l\v J#r:  
catch(IOException e){e.printStackTrace ();}
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catch(Exception e){e.printStackTrace ();} {RwwSqJ  
} &hjrJ/'^  
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private void processErrorCode(int nErrorCode) WNlWigwYl  
{ ls 'QfJm  
System.err.println("Error Code : " + nErrorCode); QBai;
p{  
} 0v+5&Jk  
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-}PD0Pzg;=  
//停止文件下载 {K_YW  
public void siteStop() /0Zwgxt4?7  
{ q\d'}:kfu  
bStop = true; |44CD3A%
 
for(int i=0;i<nStartPos.length;i++) ++Az~{W7  
fileSplitterFetch.splitterStop(); gaTI:SKzc  
h#;fBQ]   
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} $?wX*  
}
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//负责部分文件的抓取
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**FileSplitterFetch.java ~)sb\o  
*/ AO>K 6{  
package NetFox; C0KP,JS&  
*kZJ  
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import java.io.*; AkT_ZU>  
import java.net.*; cg$7`/U  
#HM0s~^w&  
]5rEwPB  
public class FileSplitterFetch extends Thread { DV{Qbe#In  
EC?!%iO`  
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String sURL; //File URL %w'@:~0  
long nStartPos; //File Snippet Start Position S WYiI  
long nEndPos; //File Snippet End Position nVs0
$?}  
int nThreadID; //Thread's ID "4n_MV>p  
boolean bDownOver = false; //Downing is over kw}J~f2  
boolean bStop = false; //Stop identical 8%vk"h:u:  
FileAccessI fileAccessI = null; //File Access interface JF24~Q4P  
V"T;3@N/4  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException vV8y_  
{ kmo3<'
j{  
this.sURL = sURL; {jggiMwo.v  
this.nStartPos = nStart; {IqbO>|"O_  
this.nEndPos = nEnd; UAUo)VVi"  
nThreadID = id; oAvL?2  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 cz&FOP+!  
} Ex
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.VTHZvyn  
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:  
public void run() !oM1  
{ FkKx~I:  
while(nStartPos < nEndPos && !bStop) V&)-u(s_S/  
{ *hFT,1WE=+  
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try{ gd/W8*NFR  
URL url = new URL(sURL);  Ur]5AJ  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 9K FWa0G  
httpConnection.setRequestProperty("User-Agent","NetFox"); olQ;XTa01F  
String sProperty = "bytes="+nStartPos+"-"; k\zNh<^  
httpConnection.setRequestProperty("RANGE",sProperty); >E[cl\5$E  
Utility.log(sProperty); 6M259*ME  
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v3.JG]zLpP  
InputStream input = httpConnection.getInputStream(); TpZ)v.w~l7  
//logResponseHead(httpConnection); d}ue/hdw  
@ ;rU#  
/v=MGX@r  
byte[] b = new byte[1024]; .i
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int nRead; ECU:3KH>MF  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ? 0nbvV5v7  
{ gQ
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nStartPos += fileAccessI.write(b,0,nRead); /':kJOk<[  
//if(nThreadID == 1) )P\ec  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); b_cD >A  
} ,58D=EgFy  
k((_~<$2K  
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Utility.log("Thread " + nThreadID + " is over!"); [ V/*{Z  
bDownOver = true; b.;F)(  
//nPos = fileAccessI.write (b,0,nRead); ks 3<zW(  
} mi<V(M~p  
catch(Exception e){e.printStackTrace ();} b^6Ooc/-k  
} }|AUV  
} Hco[p+  
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//打印回应的头信息 b@z/6y!  
public void logResponseHead(HttpURLConnection con) hPD2/M  
{ dhsQfWg#}  
for(int i=1;;i++) <E!M<!h  
{ 'd0]`2tVg4  
String header=con.getHeaderFieldKey(i); O62H4oT  
if(header!=null) ?5jkb  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); A$[@AY$MI  
Utility.log(header+" : "+con.getHeaderField(header)); trtI^^/%  
else Z5_U D  
break; DHgEhf]  
} qZCA16  
} ZIkXy*<
(  
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6'+3""\  
public void splitterStop() Y2QlK1.8V  
{ [p[Kpunr{l  
bStop = true; ~48Uch\LG:  
} |f?tyQ  
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} [bH6>{3u  
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/* 0bS\VUB(  
**FileAccess.java N3 07lGb  
*//文件访问(定位，写) :74)nbS  
package NetFox; ;~#rdL  
import java.io.*; oG3>lqBwD2  
k0!b@ c  
)TBBYCL3  
public class FileAccessI implements Serializable{ YRAWylm  
8b[^6]rM  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 %Nzg~ZPbmT  
RandomAccessFile oSavedFile; AEe*A+  
long nPos; _;L9&>!p6  
i|)<#Ywl  
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public FileAccessI() throws IOException _Cj u C`7  
{ AQQeLdTq  
this("",0); s(r(! FZ  
} q.g<gu]  
L6J=m#Ld  
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public FileAccessI(String sName,long nPos) throws IOException BC9rsb  
{ <Gr{h>b  
oSavedFile = new RandomAccessFile(sName,"rw"); Qt+ K,LY  
this.nPos = nPos; |Q?IV5%$  
oSavedFile.seek(nPos);
w8%<O^wN,  
} 1|q$Wn:*  
)$]_;JFr  
uIiE,.Uu}  
public synchronized int write(byte[] b,int nStart,int nLen) v<HhB.t.  
{ {^1D|y  
int n = -1; \%K< S  
try{ #\GWYWkR  
oSavedFile.write(b,nStart,nLen); a=.A/;|0*  
n = nLen; "z1\I\ ^  
} GxuFO5wz  
catch(IOException e) sFT-aLpL@V  
{ )F8G q,  
e.printStackTrace (); r**u=q%p  
} 4S`2")V  
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return n; #9F=+
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} F%UyFUz  
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} CC;T[b&  
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/* y9cW&rDH  
**SiteInfoBean.java kid3@  
*/  Cdin"  
package NetFox; mg;+Th&  
C{`+h163\  
)[.FUx  
public class SiteInfoBean { $8k
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)+'FTz` c  
private String sSiteURL; //Site's URL @{_[bKg  
private String sFilePath; //Saved File's Path -R?~Yysd7K  
private String sFileName; //Saved File's Name +[<|T
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private int nSplitter; //Count of Splited Downloading File 7q&Ru|T33  
.z^ePZ|mV  
}te\) Yk.N  
public SiteInfoBean() Uf}s6#  
{//nSplitter的缺省值为5 U3}r.9/  
//default value of nSplitter is 5 u]lf~EE  
this("","","",5); kAsYh4[  
} q"7rd?r52  
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dMK|l   
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) JS]6jUB<B  
{ /o Q^j'v  
sSiteURL= sURL; 9D#"Ey  
sFilePath = sPath; %SaC[9=?  
sFileName = sName; j"{|* _6E_  
this.nSplitter = nSpiltter; ?W:YS82  
-r)Q|U  
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} 2R66 WKQ  
2Z;wU]  
_Q_"_*e  
public String getSSiteURL() xE`uFHuS}  
{ u(iEuF;7  
return sSiteURL; +F=j1*'&  
} `CP#S7W^  
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public void setSSiteURL(String value) `irz'/"p  
{ }F=scbpXj  
sSiteURL = value; r`Y[XzT9  
} M S$^m2  
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public String getSFilePath() 1Tz5tU9kR  
{ p_pI=_:  
return sFilePath;
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} s tvI  
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public void setSFilePath(String value) 0%$E^`  
{ {>$i)B  
sFilePath = value; pB*8D  
} US3rkkgDO  
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T
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public String getSFileName() :)hS-*P  
{ +0)s{?  
return sFileName; \ t4:(Jp 3  
} O75^(keW  
@AET.qGC  
X!#rw= Q  
public void setSFileName(String value) v0Ww~4|],  
{ M+4>l\  
sFileName = value; fl%X>\i/7  
} {6d)|';%  
vcm66J.14  
,v(K|P@  
public int getNSplitter() Awy-kou[C  
{ qYjR  
return nSplitter; GF]V$5.ps  
} 7L2$(
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|&!04~s;E  
0*G =~:  
public void setNSplitter(int nCount) 6?GR+;/  
{ |e49F  
nSplitter = nCount; 5~)m6]-6  
} H809gm3(Z  
} %N``EnF2  
I2"
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;>%@  
/* P|c[EUT  
**Utility.java )lB 3U  
*/ YhQ;>Ko  
package NetFox; nM]Sb|1:  
-!w({rP  
qI (<5Wxl  
public class Utility { :K J#_y\rt  
)> >Tj7  
=@BVO@z@  
public Utility() W>[0u3  
{ ;J<K/YdI  
4I&e_b< 30  
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} l}\q }7\)  
qkHdr
2  
//线程睡眠 NHI(}Ea|]  
public static void sleep(int nSecond) Js{X33^Ju  
{ KYe@2 6   
try{ r5#8Vzr  
Thread.sleep(nSecond); Z]VmTB  
} m3Ma2jLWC  
catch(Exception e) !mX-g]4E  
{ 2GRL`.1  
e.printStackTrace (); MLVrL r t  
} ~%.<rc0  
} J9buf}C[  
xb6y=L  
//日志 xhq-$"B  
public static void log(String sMsg) c_p7vvI&c0  
{ 60RYw9d%0  
System.err.println(sMsg); ]!% p21e  
} )H HBf<  
[yFf(>B  
8Qm%T7]UFb  
public static void log(int sMsg) k+nfW]UNF  
{ ~6bf-Wg'X  
System.err.println(sMsg); ! J7ExfEA  
} 5}v<?<l9\  
} TDqH"q0  
)7`2FLG  
3fdx&}v/  
/* -(ev68'}W  
**TestMethod.java A.[~}ywH  
*/ %t.L;G  
package NetFox; cZVVJUF  
+c&oF,=}!P  
]x12_+  
public class TestMethod { '=eG[#gy  
lxVA:tz0  
C~o\Q#*j  
public TestMethod() V$OZC;4  
{ ///xx/weblogic60b2_win.exe P84uEDY  
try{ *{K?JB#W  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 1ha 8)L  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); P
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SiteFileFetch fileFetch = new SiteFileFetch(bean); !=/w
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fileFetch.start(); ;kE
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} Of@LEEh6  
catch(Exception e){e.printStackTrace ();} \x(ILk|'c  
[v%j?  
p$S\l]
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} f[wA]&
 
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public static void main(String[] args) |``rSEXYs  
{ L9"yQD^R7?  
new TestMethod(); gS VWv9+  
} 78u9>
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} iYPlgt/Y!  
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