http断点续传简单实现（java)

/* r|0wIpi6Q  
**SiteFileFetch.java L=-v>YL+  
*/ KFn[  
package NetFox; 0r'<aA`=I  
import java.io.*; aiwKkf`\  
import java.net.*; J4^aD;j  
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public class SiteFileFetch extends Thread { 0X4%Ccs  
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SiteInfoBean siteInfoBean = null; //文件信息Bean Jhr3[A  
long[] nStartPos; //开始位置 ;=E!xfp5U  
long[] nEndPos; //结束位置 o"e]9{+<  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 x`gsD3C  
long nFileLength; //文件长度 4
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boolean bFirst = true; //是否第一次取文件 Qj',&b  
boolean bStop = false; //停止标志 .l u
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File tmpFile; //文件下载的临时信息 e"ur+7  
DataOutputStream output; //输出到文件的输出流 |qX[Dk  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 4l
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public SiteFileFetch(SiteInfoBean bean) throws IOException s&~i S[  
{ -
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siteInfoBean = bean; qK12:  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); je^=gnq  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); $Z{Xt*  
if(tmpFile.exists ()) 2<8JY4]!]  
{ ' lMPI@C6r  
bFirst = false; `\5u/i'Ca!  
read_nPos(); ?*2Uw{~}  
} zDx*R3%  
else };s8xGW:k3  
{ 7xy[;  
nStartPos = new long[bean.getNSplitter()]; 1;N5@0%p  
nEndPos = new long[bean.getNSplitter()]; E [b6k&A  
} l5esx#([*R  
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} %[H|3  
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public void run() zKX|m-i|2  
{ !;s5\91  
//获得文件长度 t*{B
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//分割文件 r*XEne  
//实例FileSplitterFetch i*ErxWzu  
//启动FileSplitterFetch线程 68-2EWq  
//等待子线程返回 l#k&&rI5x.  
try{ 4<Q^/-W  
if(bFirst) Rx%SeM2  
{ ;<)<4N"  
nFileLength = getFileSize(); )$7-CNWr~  
if(nFileLength == -1) Emx`+9  
{ KBkS>0;X  
System.err.println("File Length is not known!"); Cqc5jx0)  
} 0mD=Rjb*a  
else if(nFileLength == -2) \zGmZZ  
{ f?|cQ[#t!\  
System.err.println("File is not access!"); z*B-`i.  
}
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else b'$fr6"O1  
{ p`2w\P3;)  
for(int i=0;i<nStartPos.length;i++) uKE?VNC]  
{ EX9os  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); |v31weD8  
} t1MK5B5jH  
for(int i=0;i<nEndPos.length-1;i++) N#zh$0!8bJ  
{ TZYz`l+v  
nEndPos = nStartPos[i+1]; ~gJJ@j 0n  
} <b$.{&K  
nEndPos[nEndPos.length-1] = nFileLength; t2 0Es  
} U+wfq%Fz  
} }10ZPaHjl+  
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oQ"J>`',  
//启动子线程 ~|5B   
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; #<EMG|&(  
for(int i=0;i<nStartPos.length;i++) >0Gdxj]\  
{ bL9vjD'}  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ;'~GuZ#I  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 9E-]S'Z  
nStartPos,nEndPos,i); r; pS_PV  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); [OK(  
fileSplitterFetch.start(); W5_aS2$  
} VYC$Q;Z  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), @^UnrKSd  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); l11+sqg  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", $>=?'wr  
nEndPos = " + nFileLength); 1}Mdo&:t  
// fileSplitterFetch[nPos.length-1].start(); fA{t\  
.tH[A[/1 a  
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//等待子线程结束 ]mSkjKw  
//int count = 0; t],5{UF  
//是否结束while循环 Z/~7N9?m(  
boolean breakWhile = false; cH>3|B*y  
yON";|*\m  
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while(!bStop) }G53"  
{ B9i<="=p  
write_nPos();  "yA=Tw  
Utility.sleep(500); I@jXW>$  
breakWhile = true; oW\kJ>!  
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for(int i=0;i<nStartPos.length;i++) u
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{ W34_@,GD  
if(!fileSplitterFetch.bDownOver) GZCX
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{ 0V[`zOO(o  
breakWhile = false; #$;i 4a  
break; ll8Zo+-[  
}  L$Yg*]\  
} CS|al(?~  
if(breakWhile) R7Z7o4jg  
break; "B3&v%b  
\~~y1.,U.  
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//count++; +fRABY5C  
//if(count>4) Wi%e9r{hU  
// siteStop(); +\/1V`  
} Wt 1]9{$  
#[$zbZ(I>:  
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System.err.println("文件下载结束！"); TQ&1!~L*  
} '%y5Dh  
catch(Exception e){e.printStackTrace ();} Q$lgC v^M  
} <7R+p;y  
ayK?\srw  
9_ru*j\  
//获得文件长度 !)-)*T  
public long getFileSize() g;mX{p_@  
{ >pRC$'Usx  
int nFileLength = -1; f<;w1sM\  
try{ Y~"5HP|  
URL url = new URL(siteInfoBean.getSSiteURL()); c[<>e#s+;  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 8o%g2 P9.  
httpConnection.setRequestProperty("User-Agent","NetFox"); xixdv{M<FF  
&V77WnOY  
YQ$EN>.eO  
int responseCode=httpConnection.getResponseCode(); _CImf1  
if(responseCode>=400) w8iXuRv  
{ /*kc|V  
processErrorCode(responseCode); i2&I<:  
return -2; //-2 represent access is error jL]Y;T8  
} #Bo3:B8  
(N[R`LN
  
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String sHeader; 2PTAIm Rq  
J_`a}ox  
aPRXK1  
for(int i=1;;i++) %|AXVv7IN>  
{ Y6:b  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); \qZ>WCp>r  
//Utility.log(in.readLine()); PL|zm5923  
sHeader=httpConnection.getHeaderFieldKey(i); &@[pJ2  
if(sHeader!=null) 7
,7-E&d  
{ Ouos f1  
if(sHeader.equals("Content-Length")) #ni:Bwtl{  
{ Da-U@e!  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); V ah&)&n  
break; R8bKE(*rxj  
} R>T9 H0  
} CAa&,ZR  
else PP&9ORG  
break; tTE]j-uT  
} Xc8 XgZk  
} p>9|JMk  
catch(IOException e){e.printStackTrace ();} aExt TE  
catch(Exception e){e.printStackTrace ();} u?7^+z  
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Utility.log(nFileLength); 8.ej65r*  
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return nFileLength; ?XllPnuKt%  
} M.3ULt8  
2|\WaH9P  
FxdWJ|rN9D  
//保存下载信息（文件指针位置） /1h ${mo~  
private void write_nPos() ^/ZNdwx  
{ t>}(`0  
try{ UZRN4tru6  
output = new DataOutputStream(new FileOutputStream(tmpFile)); z2~\ b3G  
output.writeInt(nStartPos.length); dJ.up*aR  
for(int i=0;i<nStartPos.length;i++) 6`WI S4  
{ Mi)h<lY  
// output.writeLong(nPos); ?*L{xNC#  
output.writeLong(fileSplitterFetch.nStartPos); Z>PS>6  
output.writeLong(fileSplitterFetch.nEndPos); `R 
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} Xf{ht%b  
output.close(); e4LJ3y&z"  
} p1!-|Sqq  
catch(IOException e){e.printStackTrace ();} vI \8@97  
catch(Exception e){e.printStackTrace ();} }uiD8b{I  
} 3g87ir  
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p\22_m_wd  
//读取保存的下载信息（文件指针位置） 5$&',v(  
private void read_nPos() hV}C.- 6h  
{ C8
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try{  {HbSty  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); '37 <+N  
int nCount = input.readInt(); pmc)$3u  
nStartPos = new long[nCount]; ib%'{?Q.  
nEndPos = new long[nCount]; K1CgM1v  
for(int i=0;i<nStartPos.length;i++) 4 z^7T  
{ oer3DD(  
nStartPos = input.readLong(); I(uM`g  
nEndPos = input.readLong(); +:3s f%0  
} N{#9gr3zi  
input.close(); QB"+B]rV  
} ~A_1he~  
catch(IOException e){e.printStackTrace ();} a"m-&mN  
catch(Exception e){e.printStackTrace ();} 3?Fe(!@  
} #H;1)G(/  
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private void processErrorCode(int nErrorCode) WI1DL&*B@<  
{ snP]&l+  
System.err.println("Error Code : " + nErrorCode); 2(km]H^  
} N{H#j6QW  
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8Om4G]*|,  
//停止文件下载 0-:dzf  
public void siteStop() sspGB>h8l  
{ zNM*xPgS  
bStop = true; L, 2;-b|  
for(int i=0;i<nStartPos.length;i++) zmFS]IOv$  
fileSplitterFetch.splitterStop(); !@>q^_Gez  
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} %gu|  
} rN'8,CV  
//负责部分文件的抓取 8&SWQ  
**FileSplitterFetch.java Q})&c.L  
*/ h{: ]'/@~  
package NetFox; Y-+JDrK  
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import java.io.*; K0|:+s@u  
import java.net.*; Ctbc!<@o  
:A+}fBIN  
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public class FileSplitterFetch extends Thread { mhI  
+z<GycIc?K  
y ~Fi  
String sURL; //File URL JC#5CCz  
long nStartPos; //File Snippet Start Position 70{B/ ($  
long nEndPos; //File Snippet End Position ?Kg_bvoR  
int nThreadID; //Thread's ID SN]Na<P  
boolean bDownOver = false; //Downing is over Lt
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boolean bStop = false; //Stop identical R-tZC9 @  
FileAccessI fileAccessI = null; //File Access interface y1B'_s  
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%WPyc%I  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException [Pl''[  
{ j>G|Xv  
this.sURL = sURL; 5|Oj\L{  
this.nStartPos = nStart; {E.A?yej9  
this.nEndPos = nEnd; '4}8WYKQ  
nThreadID = id; +1^L35\@  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 "sT)<Wc  
}  v>s,*  
Bm;: cmB0e  
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public void run() tBVtIOm9  
{ K/_"ybR7  
while(nStartPos < nEndPos && !bStop) 3|%0
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{ a7aj:.wi  
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try{ pJIJ"o'>.9  
URL url = new URL(sURL); o%*C7bU  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); H.[nr:  
httpConnection.setRequestProperty("User-Agent","NetFox"); %<`sDO6Q
?  
String sProperty = "bytes="+nStartPos+"-"; >J#/IjCW  
httpConnection.setRequestProperty("RANGE",sProperty); GK[Hs1/  
Utility.log(sProperty); JvkTfTE7  
#'n.az=1  
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InputStream input = httpConnection.getInputStream(); hFnUw26P  
//logResponseHead(httpConnection); )Myx(w"S  
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byte[] b = new byte[1024]; IY|`$sHb  
int nRead; `VF_rC[?  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) yb,$UT"]  
{ :KqSMuKR  
nStartPos += fileAccessI.write(b,0,nRead); <sSH^J4QqX  
//if(nThreadID == 1) Tj}%G  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); FiSx"o  
} ~V0 GRPnI  
\jb62Jp  
+No` 89Y  
Utility.log("Thread " + nThreadID + " is over!"); #kE8EhQZ  
bDownOver = true; Gd$!xN%O  
//nPos = fileAccessI.write (b,0,nRead); /x<uv_"  
} F$i 6
 
catch(Exception e){e.printStackTrace ();} 39I|.B"  
} < <F  
} \-sW>LIA  
s>%.bAxc  
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//打印回应的头信息 ;.^! 7j  
public void logResponseHead(HttpURLConnection con) (}s& 84!  
{ c}s#!|E0v  
for(int i=1;;i++) dH'0
2[;  
{ ZQn>+c2%!  
String header=con.getHeaderFieldKey(i); BAi`{?z$<  
if(header!=null) FAX[|p  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 8_py
fb  
Utility.log(header+" : "+con.getHeaderField(header)); nJ$2RN  
else TpI8mDO\W  
break; FL4BdJ\  
} '6\ZgO
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} pH(X;OC9S  
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public void splitterStop() %Y,Ru)5}  
{ 8l'W[6  
bStop = true; PXML1.r$Q  
} e,d}4 jy  
@
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} }R%*J  
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/* 'Yd
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**FileAccess.java JSID@ n<b?  
*//文件访问(定位，写) *IIA"tC  
package NetFox; )2#qi/  
import java.io.*; [XubzZ9  
7U-}Y  
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public class FileAccessI implements Serializable{ PjXiYc&  
OUFy=5(%:  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 G6lC[eK  
RandomAccessFile oSavedFile; Xk1uCVUe5  
long nPos; j<`3xd'  
8(\J~I[^  
7SNdC8GZ~  
public FileAccessI() throws IOException lBm`W]3T  
{ 3,2$Ny3N  
this("",0); w'XN<RWA  
} j\zlp  
r^H,H'BohJ  
/^v!B`A@  
public FileAccessI(String sName,long nPos) throws IOException 9JX@ck  
{ {:3:GdM6  
oSavedFile = new RandomAccessFile(sName,"rw"); %3AE2"  
this.nPos = nPos; pvb&vtp  
oSavedFile.seek(nPos); 1.PN_9%  
} ?\(qA+iP0  
m*YfbOhs#  
FnI}N;"  
public synchronized int write(byte[] b,int nStart,int nLen) #)@#Qd  
{ ZJm$7T)V  
int n = -1; 0-;>O|U3  
try{ =vvd)og  
oSavedFile.write(b,nStart,nLen); (h=]Ox  
n = nLen; /W .G-|:  
} 5#s],h  
catch(IOException e) Ab>Kfr#  
{ ]mz'(t
  
e.printStackTrace (); qkz|r?R)  
} [h !
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return n; "K$c9Z8
 
} &[ ],rT  
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} '[HQ}Wvn  

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/* kjB'WzZ8  
**SiteInfoBean.java Qe-Pg^PS]  
*/ D~Ef%!&  
package NetFox; d{t@+}0.u  
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ue  
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public class SiteInfoBean { #sB
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0 f$96sl  
G 9(*F  
private String sSiteURL; //Site's URL JtsXMZz  
private String sFilePath; //Saved File's Path l'@!'  
private String sFileName; //Saved File's Name B3D}'<  
private int nSplitter; //Count of Splited Downloading File VBS}2>p  
MkjB4:"  
"'@D\e}  
public SiteInfoBean() 7Z~JuTIZ  
{//nSplitter的缺省值为5 *9xxX,QT8Q  
//default value of nSplitter is 5 <2L,+  
this("","","",5); %{pjC7j#  
} Q672iR\#)  
~d1=_p:~T  
x X[WX#'f  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) GQk/ G0*&  
{ e$WAf`*  
sSiteURL= sURL; 6({)O1Z  
sFilePath = sPath; []aw;\7}Y  
sFileName = sName; %<+uJ'pj  
this.nSplitter = nSpiltter; 3$q#^UvD  
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4b((,u$  
} @"A 5yD5
  
WT")tjVKA  
_|cSXZ|  
public String getSSiteURL() TQ:5@1aT  
{ %3"3V1  
return sSiteURL; 85)C7tJ-g  
} F$jy~W_  
&|}QdbW  
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public void setSSiteURL(String value) 2boyBz}=S  
{ }9
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sSiteURL = value; Vdefgq@<  
} Y`{62J8oy  
,c$tKj5ulQ  

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public String getSFilePath() (*=>YE'V{  
{ g6aqsa  
return sFilePath; @ S[As~9X  
} YVvE>1z  
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public void setSFilePath(String value) 4lpcJ+:o  
{ AXte
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sFilePath = value; t 4zUj%F  
} {r$Ewc$Yb7  
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public String getSFileName() E>i<2  
{ FG{,l=Z0  
return sFileName; xV`l6QS  
} 4 qY  
`-
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1KGf @u%-1  
public void setSFileName(String value) .9=4Af  
{ .5!`wwVi  
sFileName = value; ,7:-V<'Yv  
} ef&8L  
!.q99DB  
hcRe,}wJ  
public int getNSplitter() jP_s(PQ  
{ ~_"V7  
return nSplitter; [>pBz3fn,  
} +WR?<*_  
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@Lf&[_  
public void setNSplitter(int nCount) >`a^E1)  
{ Vp~ cN  
nSplitter = nCount; 6| o S 5  
} v<g~EjzCf  
} febn?|@  
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/* |[mmEYc  
**Utility.java <%%)C>l  
*/ Qk>U=]U  
package NetFox; (`E`xb@E,=  
%,z;W-#gnY  
4%8den,|  
public class Utility { cuumQQ  
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public Utility() %xG
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{ nh5=0{va|L  
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} b
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tJ6Q7 J;n  
//线程睡眠 ~8mz.ZdY  
public static void sleep(int nSecond) hgW1g#
  
{ ^,
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try{ ]1>R8   
Thread.sleep(nSecond); TIl 'Z7  
} 4@Db $PHs  
catch(Exception e) U*\K<fw   
{ l4r>#n\yj  
e.printStackTrace (); ];6955I!  
} Ai[@2AyU  
} K$qY^oyQFw  
3(t,x  
//日志 z#PaQ
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public static void log(String sMsg) ru9@|FgAE  
{ (>ze{T|  
System.err.println(sMsg); F<6(Hw#>  
} }v|_]   
+_pfBJ_$%  
XR7v
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public static void log(int sMsg) rFzj\%xa[  
{ tN\I2wm  
System.err.println(sMsg); o@.{|j  
} w}OBp^V^  
} cUG^^3!  
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/Mw;oP{&b  
/* dm=?o  
**TestMethod.java r"
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*/ 8UgogNR\  
package NetFox; "]q xjs^3?  
^<cJ;u*0  
o/VT"cT  
public class TestMethod { Z:
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aZ_3@I{d`  
f sh9-iY8e  
public TestMethod() lkJxb~S  
{ ///xx/weblogic60b2_win.exe ,K\7y2/  
try{ %]0?vw:;j  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); et)n`NlcK  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); D
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SiteFileFetch fileFetch = new SiteFileFetch(bean); 1Hr1Ir<KR  
fileFetch.start(); W]7<PL*u  
} i\/'w]  
catch(Exception e){e.printStackTrace ();} L8h!%56s  
)~R[aXkvY  
Cx/J_Ro#  
} R?:Q=7K  
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public static void main(String[] args)
vWESu4W`L  
{ ~!PWJ~U  
new TestMethod(); L YB@L06a  
} EZI#CLT[  
} $<2d|;7r  
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