http断点续传简单实现（java)

/* L7buY(F(  
**SiteFileFetch.java ?# FYF\P  
*/ UzaAL9
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package NetFox; 4z(B`t~7  
import java.io.*; xRacgny:I  
import java.net.*; \XV8t|*  
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public class SiteFileFetch extends Thread { ]b%U9hmL^f  
}W}(k2r  
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SiteInfoBean siteInfoBean = null; //文件信息Bean fm-m?=  
long[] nStartPos; //开始位置 IxCesh  
long[] nEndPos; //结束位置 d-1D:Hs?  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 igA?E56?  
long nFileLength; //文件长度 NT5=%X]  
boolean bFirst = true; //是否第一次取文件 u'#/vT#l  
boolean bStop = false; //停止标志 !;|#=A9  
File tmpFile; //文件下载的临时信息 }WIkNG4{Z  
DataOutputStream output; //输出到文件的输出流 E,.PT^au  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） tW|0_m>{  
public SiteFileFetch(SiteInfoBean bean) throws IOException i,<'AL )  
{ Itr4Pr  
siteInfoBean = bean; #%nV\ Bl  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 9n\>Yieu  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 2sIt~ Gn  
if(tmpFile.exists ()) $3 -QM  
{ Anyy
 
bFirst = false; r_$*euh@  
read_nPos(); @,.D]43  
} ?K7uy5Y  
else r6uN6XCM  
{ "NA<^2W@J  
nStartPos = new long[bean.getNSplitter()]; XyN " Jr  
nEndPos = new long[bean.getNSplitter()]; $+GDPYm'  
} }wiyEVAh{  
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@ !su7  
k*N!U[]  
}
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public void run() cdL]s^z  
{ 5e,u*J]  
//获得文件长度 |3e+ 
K.  
//分割文件 l%_K
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//实例FileSplitterFetch $aJ6i7C,j}  
//启动FileSplitterFetch线程 L$_%T  
//等待子线程返回 3f^Pr  
try{ \h=*pAf  
if(bFirst) vq(#I
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{ L#K`F8Wi=  
nFileLength = getFileSize(); vx($o9  
if(nFileLength == -1) XjL3Ar*  
{ &j1-Ouy  
System.err.println("File Length is not known!"); $L0sBW&  
} I m I$~q'  
else if(nFileLength == -2) 8k-]u3  
{ I?PqWG!O  
System.err.println("File is not access!"); X$6NJ(2G  
} 2T+-[}*  
else ^4$4x  
{ i \
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for(int i=0;i<nStartPos.length;i++) ]Pe>T&  
{ :po6%}hn  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ;: _K,FU  
} SZe55mK`  
for(int i=0;i<nEndPos.length-1;i++) ;@qS#7SRB  
{ _"
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nEndPos = nStartPos[i+1]; M#o.O?.`  
} ``jNj1t{}  
nEndPos[nEndPos.length-1] = nFileLength; 1!(lpp
 
} Y}R$RDRL  
} 2 G_KTYJ  
+U<YM94?  
B@M9oN
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//启动子线程 <9X@\uvU.<  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; yR|2><A  
for(int i=0;i<nStartPos.length;i++) uFSU|SDd.  
{ M]6+s`?r  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), \78^ O  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), n?cC]k;P~  
nStartPos,nEndPos,i); 082iEG  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); dVB#Np  
fileSplitterFetch.start(); *KDTBd  
} [pTdeg;QE  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), c|.te]!ds  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); {Cm!5QYy  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ,L-/7}"VHA  
nEndPos = " + nFileLength);
#T8o+tv  
// fileSplitterFetch[nPos.length-1].start(); YRVh[Bqg`  
qI7KWUR  
td7(444]  
//等待子线程结束 Vxap+<m  
//int count = 0; b3-j2`#  
//是否结束while循环 +7w5m  
boolean breakWhile = false; rZdOU?U  
Lp:VU-S  
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while(!bStop) #[9UCX^=  
{ lfDd%.:q4S  
write_nPos(); :a/rwZ[r  
Utility.sleep(500); 13F]7l-#  
breakWhile = true; C5ILVQ  
1z7+:~;l  
^ 34Ng  
for(int i=0;i<nStartPos.length;i++) jw{N#QDh  
{ `ZEFH7P  
if(!fileSplitterFetch.bDownOver) ,z
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{ c6vJ;iz  
breakWhile = false; dQ{qA(m  
break; C8|Ls(4Ck  
} ]'Eg2(wy  
} zGU MH7 M  
if(breakWhile) ~*1>)P8]#  
break; ;6PU  
VI4mEq,V  
UZs '[pm)  
//count++; Jkj
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//if(count>4) 9*s8%pL  
// siteStop(); | CFG<]  
} QxW+|Gt._  
}O~D3z4l0  
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System.err.println("文件下载结束！");  sG#Os  
} ?1\I/'E9  
catch(Exception e){e.printStackTrace ();} B(Yg1jAe  
} 4_-&PZ,d  
3LfF{ED@  
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//获得文件长度 wp1O*)/q  
public long getFileSize() qc,EazmU  
{ `&c[s%0  
int nFileLength = -1; XlF,_  
try{ W'@G5e  
URL url = new URL(siteInfoBean.getSSiteURL()); H.l0kBeG  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); &q|
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httpConnection.setRequestProperty("User-Agent","NetFox"); W[J2>`k9  
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int responseCode=httpConnection.getResponseCode(); tZ62T{, a  
if(responseCode>=400) f91]0B`C  
{ Bv~^keuj3t  
processErrorCode(responseCode); `?=3[  
return -2; //-2 represent access is error $=\=80u/  
} ]*a(^*}A%  
0O'M^[=d.8  
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String sHeader; {'zS8  
)XonFI  
r&R~a9+)  
for(int i=1;;i++) )R `d x  
{ 83vZR
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//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); >b\|%=(x!*  
//Utility.log(in.readLine()); v0) %S  
sHeader=httpConnection.getHeaderFieldKey(i); E!}'cxb^  
if(sHeader!=null) g0biw?  
{ fsOlg9  
if(sHeader.equals("Content-Length")) l,Q`;v5|  
{ 31^/9lb  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 90+Vw`Gz=  
break; /'{vDxZf R  
} <fBJ@>  
} tBzE(vW  
else =AaF$R  
break; JQbaD-  
} +?6]Vu&|f  
} SPb`Q"  
catch(IOException e){e.printStackTrace ();} g~21|Sa$[  
catch(Exception e){e.printStackTrace ();} pSQ2wjps  
qdk!.A{  
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Utility.log(nFileLength); bl!
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return nFileLength; +/$&P3  
} ^-?^iWQG  
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C\"C12n{  
//保存下载信息（文件指针位置） %6fnL~A  
private void write_nPos() Nz{q
u}dt  
{ _gK}Gi?|  
try{ ZJbaioc\  
output = new DataOutputStream(new FileOutputStream(tmpFile)); -{*3<2rFK  
output.writeInt(nStartPos.length); ]+ub R;  
for(int i=0;i<nStartPos.length;i++) 1^NC=IS9z  
{ BIMX2.S1o  
// output.writeLong(nPos); [Y
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output.writeLong(fileSplitterFetch.nStartPos); $H@
  
output.writeLong(fileSplitterFetch.nEndPos); oAN,_1v)  
} ~-sgk"$  
output.close(); ozS'n]8*  
} `>KNa"b%$  
catch(IOException e){e.printStackTrace ();} &'e+`\  
catch(Exception e){e.printStackTrace ();} aO |@w"p8  
} =
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//读取保存的下载信息（文件指针位置） z
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private void read_nPos() ysp,:)-%G@  
{ =1>G* ,  
try{ c9H6\&  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); bp8sZK"z  
int nCount = input.readInt(); dh{py  
nStartPos = new long[nCount]; Da! fwth  
nEndPos = new long[nCount]; /C`AA/@  
for(int i=0;i<nStartPos.length;i++) ~^Al#@  
{ s$f9?(,.Ay  
nStartPos = input.readLong(); se3EI1
e  
nEndPos = input.readLong(); ec^{ez@`  
} kQ\l7xd  
input.close(); o\tw)_ >  
} s!gVY!0  
catch(IOException e){e.printStackTrace ();} F_@` <d!  
catch(Exception e){e.printStackTrace ();} %eHr^j~w$  
} cc=_KYZ1k  
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}<
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private void processErrorCode(int nErrorCode) v^/<2/E"?4  
{ h3>u[cX%  
System.err.println("Error Code : " + nErrorCode); b't6ekkN  
} :L:] 3L  
\A!Iln  
&>.QDO  
//停止文件下载 :O,,fJ<x.O  
public void siteStop() uUBUUr  
{ WM$Z?CN%KB  
bStop = true; 'YN:c
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for(int i=0;i<nStartPos.length;i++) n~>b}DY  
fileSplitterFetch.splitterStop(); -H\j-k  
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} *.$ov<E.  
} &j'k9C2p  
//负责部分文件的抓取 kMzDmgoxNg  
**FileSplitterFetch.java * kL>9  
*/ ):+^893)  
package NetFox; k|]l2zlT  
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import java.io.*; M?gZKdj  
import java.net.*; $y<`Jy]+)~  
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public class FileSplitterFetch extends Thread { kiin78W  
iRW5*-66f  
.aK=z)  
String sURL; //File URL [;toumv  
long nStartPos; //File Snippet Start Position (Ze\<Y#cv  
long nEndPos; //File Snippet End Position `"~X1;  
int nThreadID; //Thread's ID 7|J&fc5BP  
boolean bDownOver = false; //Downing is over i7\>uni  
boolean bStop = false; //Stop identical a(JtGjTf&  
FileAccessI fileAccessI = null; //File Access interface y </i1qM  
{c1wJ  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException !"08TCc<  
{ guy!/zQ>A  
this.sURL = sURL; @[/!e`]+  
this.nStartPos = nStart; %<q"&]e,  
this.nEndPos = nEnd; )5<dmK@  
nThreadID = id; Vz5<Gr  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 DAN"&&  
} nu|?F\o!  
>NpW$P{'  
@6U&7
!  
public void run() u7p:6W  
{ 0eCjK.  
while(nStartPos < nEndPos && !bStop) v!mP9c j  
{ phwq#AxQ  
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try{ 4uVyf^f\]f  
URL url = new URL(sURL); -x/g+T-  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ~F~hgVS5  
httpConnection.setRequestProperty("User-Agent","NetFox"); ov>`MCS,v  
String sProperty = "bytes="+nStartPos+"-"; ,b+Hy`t  
httpConnection.setRequestProperty("RANGE",sProperty); ws]d,]  
Utility.log(sProperty); BIvz55g  
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InputStream input = httpConnection.getInputStream(); 127@ TN"  
//logResponseHead(httpConnection); QX-M'ur99  
~vR<UQz  
;ZrFy=Iv  
byte[] b = new byte[1024]; 5kv]k?   
int nRead; q 7+|U%!9  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) yg4ILL  
{ G_5NS<JE"S  
nStartPos += fileAccessI.write(b,0,nRead); +A_jm!tJS(  
//if(nThreadID == 1) 1@<>GDB9  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); B7'2@+(  
} *EtC4sP  
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Utility.log("Thread " + nThreadID + " is over!"); `\-MpNw  
bDownOver = true; 6z67%U*8r  
//nPos = fileAccessI.write (b,0,nRead); KkHlMw
v  
} 1[dQVJqMp(  
catch(Exception e){e.printStackTrace ();} dp1t]  
} W?@+LQa??  
} 
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tki
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_..5G7%#%  
//打印回应的头信息 l?beqw:  
public void logResponseHead(HttpURLConnection con) Cmj `WSSa  
{ 'ka"0~:NS{  
for(int i=1;;i++) stCFLYox  
{ yD ur9Qd6  
String header=con.getHeaderFieldKey(i); lzZ=!dG  
if(header!=null) 5g4c1K  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); jmnrpXaAx  
Utility.log(header+" : "+con.getHeaderField(header)); jRdW=/q+(  
else U09@pne8  
break; RKz _GEH)  
} y|D-W>0cX3  
} `VOLw*Ci  
]JHY(H
2|  
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public void splitterStop() 'seuO!5  
{ (pQ$<c  
bStop = true; ^m^,:]I0P  
} ]h&?^
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IRDD   
} .rbKvd?-}  
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/* >5]w\^QN9_  
**FileAccess.java "[]J[!}x  
*//文件访问(定位，写) L2y{\<JC"  
package NetFox; |.U- yyz  
import java.io.*; ,%]s:vk[u  
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3qH`zYg
h  
public class FileAccessI implements Serializable{ 3_k3U  
N_8L8ds5  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 }A_>J7w  
RandomAccessFile oSavedFile; ~f%AbDye  
long nPos; cE]#23  
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public FileAccessI() throws IOException ;%aWA  
{ }=."X8zOI8  
this("",0); jLf87  
} 1
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r;aP`MVO<  
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public FileAccessI(String sName,long nPos) throws IOException vui{["  
{ 38q0iAH  
oSavedFile = new RandomAccessFile(sName,"rw"); 'r?Oz
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this.nPos = nPos; g7W\ &  
oSavedFile.seek(nPos); I*)eP||  
} ma4r/8Q  
gbRdng7(}  
/-)|dP  
public synchronized int write(byte[] b,int nStart,int nLen) -`ykVHgg  
{ U^X8{,8O  
int n = -1; -?<L"u  
try{ 5Bc)QKh`l|  
oSavedFile.write(b,nStart,nLen); ? &;d)TQ  
n = nLen; ed)!Snz   
} N[,/VCW  
catch(IOException e) pV))g e\  
{ 6ypqnOTr  
e.printStackTrace (); V_7xXuM/  
} :`P;(h  
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return n; EMejvPnZO  
} $$G^#t1=XZ  
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} *8CE0;p'k  
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6.'+y1yS)  
/* |]H2a;vUJR  
**SiteInfoBean.java Wh>Y_ k  
*/ 9qQFIw~S  
package NetFox; @V-CG!  
&_E*]Sj\  
#0WO~wL  
public class SiteInfoBean { cBA2;5E  
$T0|zPK5  
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private String sSiteURL; //Site's URL ]g;K_>@  
private String sFilePath; //Saved File's Path W}1h~rNy  
private String sFileName; //Saved File's Name |KC
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private int nSplitter; //Count of Splited Downloading File Kn9,N@bU_  
CQ3{'"b  
w65 $ R  
public SiteInfoBean()
i=<(fq  
{//nSplitter的缺省值为5 <!|2Ru  
//default value of nSplitter is 5 GS3ydN<v  
this("","","",5); 2WOdTM{u  
} 7iKbd  
XfT6,h7vFL  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) .ODtduURe  
{ =;$&:Zjy/%  
sSiteURL= sURL; kB]|4CG{
 
sFilePath = sPath; n%<.,(.(S  
sFileName = sName; hTn }AsfLY  
this.nSplitter = nSpiltter; g `B?bBg  
#zt+U^#)  
vP'R7r2Yx  
} 3-8Vw$u  
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public String getSSiteURL() {ersXQ
:  
{ e"|9%AW@<  
return sSiteURL; 8YN+
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} wL 5).`oq  
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public void setSSiteURL(String value) <STjB,_s  
{ CsR~qQ 5  
sSiteURL = value; uYMW5k_,>  
} {hRAR8  
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95
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public String getSFilePath() %r!  
{ T+4Musu{V  
return sFilePath; j`'=K_+nU  
} W3 8=fyD  
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public void setSFilePath(String value) M3F8@|2  
{ a<gzI  
sFilePath = value; n(f&uV_):  
} |ns^'q  
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public String getSFileName() Hab9~v ]  
{ xG}eiUbM`  
return sFileName; +ic~Sar  
} *}w.xt  
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public void setSFileName(String value) T)Nis~  
{ >v<}$v6D~  
sFileName = value; ,.}PZL  
} uV 6f~cQ  
cW GU?cv}  
3iEcLhe"4  
public int getNSplitter() BS|-E6E<  
{ dadMwe_l0  
return nSplitter; w pCS]2  
} (x$k\H  
_mkI;<d]$T  
63u'-Z"4  
public void setNSplitter(int nCount) )sS<%Xf  
{ @e0Q+
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nSplitter = nCount; $0W0+A$  
} 'b^:"\t'Rh  
} t=e0z^2i+  
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/* 6|dUz*Pr|\  
**Utility.java >I
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*/ ev guw*u  
package NetFox; yauP j&^R  
d,)F #;^5  
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public class Utility { <m6I)}K  
p$%h!.~99T  
ca-n:1  
public Utility() u('OHPqq  
{ 0'~b<>G%  
XWUTb\@  
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} n `Xz<Q!  
2E1TJ.[BS  
//线程睡眠 =91'.c<  
public static void sleep(int nSecond) vaxg^n|v9  
{ G[^G~U\+!  
try{ &S-& 'ZAY  
Thread.sleep(nSecond); 0,A?*CO  
} O#U
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catch(Exception e) ) k2NF="o  
{ JZnWzqFw  
e.printStackTrace (); 0Its;|  
} mcXakWmi  
} jh?7+(Cw  
qlxW@|  
//日志 uE|[7,D7;u  
public static void log(String sMsg) -*Pt78
1  
{ eS=k 48'U  
System.err.println(sMsg); ?7p| F^  
} X}=f{/\S  
i|O7nB@  
<&Uk!1Jd  
public static void log(int sMsg) G
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{ [uY2Nh  
System.err.println(sMsg); 7r<>^j'  
} j`GbI0,bT  
} ,6bMfz  
ppD~xg]  
9}mp,egV  
/* E9:hK  
**TestMethod.java 0X-2).nu  
*/ \O?B9_  
package NetFox; stG&(M  
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*u>\&`h=  
public class TestMethod { iQIw]*h^  
`;qZ$HH  
:&-}S>pC  
public TestMethod() (R}X(u  
{ ///xx/weblogic60b2_win.exe yfW^wyDd2o  
try{ IjRmpVcwN  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); M^f1D&A  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); S3w?Zk3hO  
SiteFileFetch fileFetch = new SiteFileFetch(bean); C
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fileFetch.start(); ;X6y.1N~  
} [Z+,)-ke  
catch(Exception e){e.printStackTrace ();} #dt2'V- ,  
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} 11T\2&Q  

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public static void main(String[] args) \@3  
{ &NQR*Tn  
new TestMethod(); eM"mP&TTL  
} ]."c4S_)|  
} W>
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