http断点续传简单实现（java)

/* %c [F;ug  
**SiteFileFetch.java a_ `[Lj  
*/ h~p>re  
package NetFox; o4%y>d)  
import java.io.*; C":o/;,1  
import java.net.*; t: IN,Kl4  
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public class SiteFileFetch extends Thread { ;[W"mlM  
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SiteInfoBean siteInfoBean = null; //文件信息Bean >j'ZPwj^  
long[] nStartPos; //开始位置 ooV3gj4  
long[] nEndPos; //结束位置 rN%F) q#  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 baP^<w^  
long nFileLength; //文件长度 ]]&M@FM2z  
boolean bFirst = true; //是否第一次取文件 qWx][D"  
boolean bStop = false; //停止标志 (vB<%l.&  
File tmpFile; //文件下载的临时信息 @E-\ J7 yh  
DataOutputStream output; //输出到文件的输出流 m^#rB`0;L  
d ,Y#H0`  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） &CIVL#];e  
public SiteFileFetch(SiteInfoBean bean) throws IOException un=2}@
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{ Oer^Rk  
siteInfoBean = bean; .>mr%#p  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); a9T@$:  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); !O#dV1wAa  
if(tmpFile.exists ()) 0%Z]h?EYy|  
{ .%^]9/4  
bFirst = false; :pF_GkG  
read_nPos(); A5H3%o(6k  
} Vm df8[5  
else T<L^N+<,{N  
{ Pf_S[ sm  
nStartPos = new long[bean.getNSplitter()]; E-{^E.w1  
nEndPos = new long[bean.getNSplitter()]; ;?6No(/  
} KMV=%o  
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} PZm:T+5H  
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public void run() #."Hh<C  
{ 3`#6ACF  
//获得文件长度 (lGaPMEU}  
//分割文件 N,f4*PQ  
//实例FileSplitterFetch 2PeR   
//启动FileSplitterFetch线程 E^rbcGJ  
//等待子线程返回 =Me5ftw  
try{ sj8~?O  
if(bFirst) Ht-t1q  
{ k $fGom  
nFileLength = getFileSize(); F! X}(N?t  
if(nFileLength == -1) Z{ u a=0  
{ $F/EJ
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System.err.println("File Length is not known!"); [tH-D$V  
} A5+rd{k/  
else if(nFileLength == -2) JGFt0He]  
{ =fYL}m5E  
System.err.println("File is not access!"); PT^c^{V  
} AxZD-|.  
else @_"9Dy Y%  
{ O4g+D#Lu  
for(int i=0;i<nStartPos.length;i++) s (0*  
{ 1O!/g  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); DEw8*MN  
} s%!`kWVJ.  
for(int i=0;i<nEndPos.length-1;i++) v @O&t4  
{ V=X:=  
nEndPos = nStartPos[i+1]; ; h`0ir4[A  
} )m&U#S _;  
nEndPos[nEndPos.length-1] = nFileLength; H%1$,]F  
} X<MO7I  
} c=[O `/f  
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{ K_kPgKS  
//启动子线程 x%<  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; =B];?%  
for(int i=0;i<nStartPos.length;i++) 1Fe^Qb5G  
{ (Si=m;g  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), p:OPwD+  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 2qHf'  
nStartPos,nEndPos,i); >F@qpjoQE  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ooj~&fu  
fileSplitterFetch.start(); ?+t1M
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} 8LI-gp\ 2  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), {Rear2  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); JI/_ce  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", X>I)~z}9#  
nEndPos = " + nFileLength); a|BcnYN  
// fileSplitterFetch[nPos.length-1].start(); $x#FgD(iI  
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H3H_u4_?SE  
//等待子线程结束 /R LI,.%  
//int count = 0; NJ
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//是否结束while循环 X]y)ZF26  
boolean breakWhile = false; Dl&GJ`&:p  
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while(!bStop) m,R Dr  
{ jDRe)bo4  
write_nPos(); ;c
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Utility.sleep(500); ;&b%Se@#p  
breakWhile = true; u0RS)&   
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for(int i=0;i<nStartPos.length;i++) ya -i^i\  
{ *<'M!iRC  
if(!fileSplitterFetch.bDownOver) o]LRzI  
{ /EMJSr  
breakWhile = false; "{E qhR~  
break; vZ#!uU^a:  
} f7hXQ
|$  
}  Q2p)7G  
if(breakWhile) $>R(W=Q  
break; @cq`:_.[  
&48_2Q"{  
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//count++; rxO2js  
//if(count>4) AY SSa 1}  
// siteStop(); [Qdq}FYr  
} ir:d'g1k  
 ?W0(|9  
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System.err.println("文件下载结束！");
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} R 4wr  
catch(Exception e){e.printStackTrace ();} +jqj6O@Tjr  
} jAND7&W  
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//获得文件长度 #*c F8NV-  
public long getFileSize() 'ZQWYr9R  
{ tVqmn  
int nFileLength = -1; X8<2L2:  
try{ n(lk dw  
URL url = new URL(siteInfoBean.getSSiteURL()); lM#A3/=K  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); O}#yijU3e  
httpConnection.setRequestProperty("User-Agent","NetFox"); &s)0z)mR8&  
3,);0@I  
7W9~1 .SC  
int responseCode=httpConnection.getResponseCode(); IC{F.2D  
if(responseCode>=400) Gy@7Xf  
{ :&J8.G^  
processErrorCode(responseCode); (D{Ys'{q  
return -2; //-2 represent access is error }'=h4yI  
} 0+b0<  
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String sHeader; l#@&~f[  
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for(int i=1;;i++) 1Qh`6Ya f  
{ Z0
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//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); L|^o71t|  
//Utility.log(in.readLine()); DI&MC9j(   
sHeader=httpConnection.getHeaderFieldKey(i); YCw('i(|  
if(sHeader!=null) sg'NBAo"  
{ 6U,fz#<,}  
if(sHeader.equals("Content-Length")) d `j?7Z  
{ {5Eyr$  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); c-5jYwV  
break; E/za@W  
} )Hf~d=GG  
} EX?h0Uy  
else ~4)Y#IxL  
break; qSQ@p\O~  
} -{9Gagy2&  
} LxT rG)4  
catch(IOException e){e.printStackTrace ();} PaVO"y]C  
catch(Exception e){e.printStackTrace ();} !%mi&ak(Rn  
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Utility.log(nFileLength); l_v*7d  
1.
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return nFileLength; E'%lxr  
} n=`w9qajd  
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//保存下载信息（文件指针位置） 9NWloK6bT  
private void write_nPos() kU
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{ n9fk,3  
try{ Q
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output = new DataOutputStream(new FileOutputStream(tmpFile)); '8r8%XI  
output.writeInt(nStartPos.length); :pd&dg!5  
for(int i=0;i<nStartPos.length;i++) 8Inx/>eOI  
{ (^H5EeGV{  
// output.writeLong(nPos); pN$;!  
output.writeLong(fileSplitterFetch.nStartPos); 8U^D(jrz  
output.writeLong(fileSplitterFetch.nEndPos); S?,_<GD)w  
} 6;JP76PD  
output.close(); >I-g[*  
} ?`A9(#ySM  
catch(IOException e){e.printStackTrace ();} \Hs|$   
catch(Exception e){e.printStackTrace ();} e}Q>\t45  
} vOgLEN&]  
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//读取保存的下载信息（文件指针位置）
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private void read_nPos() {NeWdC  
{ l.7d$8'\  
try{ IIaxgfhZ  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 5w-JPjH  
int nCount = input.readInt(); zKJ.Tj W  
nStartPos = new long[nCount]; _[1^
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nEndPos = new long[nCount]; kV
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for(int i=0;i<nStartPos.length;i++) QV/";A3k  
{ d +xA:  
nStartPos = input.readLong(); PEy/k.  
nEndPos = input.readLong(); 1CiA 8  
} S$K}v,8.sr  
input.close(); .b _?-Fv  
} 3G&0Ciet  
catch(IOException e){e.printStackTrace ();} ~@YQ,\Y  
catch(Exception e){e.printStackTrace ();}
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} ! o^Ic`FhS  
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private void processErrorCode(int nErrorCode) 6+Jry@  
{ V5Xi '=  
System.err.println("Error Code : " + nErrorCode); =z-5  
}  0dh#/  
?{j@6,
 
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//停止文件下载 %|jzEBz@  
public void siteStop() /=trj5h  
{ 1uC;$Aj6:  
bStop = true; ^5>du~d  
for(int i=0;i<nStartPos.length;i++) "<*nZ~nE)  
fileSplitterFetch.splitterStop(); 8;8YA1@w  
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} -? Tz.y&  
} 3]_qj*V
 
//负责部分文件的抓取 'f6PjI  
**FileSplitterFetch.java /B=l,:TnJ  
*/ (h|ch#  
package NetFox; =Pj@g/25u  
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import java.io.*; S"{GlRpd  
import java.net.*; \2Xx%SX  
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public class FileSplitterFetch extends Thread { 3/l\ <{  
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String sURL; //File URL ~BtKd*~*  
long nStartPos; //File Snippet Start Position s~)L_ p  
long nEndPos; //File Snippet End Position f^u^-l  
int nThreadID; //Thread's ID J& )#G@fRX  
boolean bDownOver = false; //Downing is over
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boolean bStop = false; //Stop identical XW^8A77H  
FileAccessI fileAccessI = null; //File Access interface 0&Qsk!-B  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException &8waih(|  
{ $mD>rx  
this.sURL = sURL; ret0z|  
this.nStartPos = nStart; 9,w}Xe=C  
this.nEndPos = nEnd; H):-!?:  
nThreadID = id; 1N>6rN  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 `LE^:a:8,  
} L!&$c&=xf  
2@4x"F]U;  
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public void run() N-D(y  
{ ,b:n1  
while(nStartPos < nEndPos && !bStop) {:3.27jQ  
{ l3BD <PB2S  
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try{ C#ZhsWS!b  
URL url = new URL(sURL); Y=3X9%v9g  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ckAsGF_B~!  
httpConnection.setRequestProperty("User-Agent","NetFox"); QP+c?ct}hF  
String sProperty = "bytes="+nStartPos+"-"; 'xsbm^n6a&  
httpConnection.setRequestProperty("RANGE",sProperty); :cEd[J
m9  
Utility.log(sProperty); G{/;AK  
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InputStream input = httpConnection.getInputStream(); E3LBPXK  
//logResponseHead(httpConnection); r7RU"H:j8  
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byte[] b = new byte[1024]; Oq[i &  
int nRead; WBy[m ?d  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) <8g=BWA  
{ !8we8)7  
nStartPos += fileAccessI.write(b,0,nRead); L#`7FaM?  
//if(nThreadID == 1) >kt~vJI  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); <s
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} >6XDX=JVI  
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bd}
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Utility.log("Thread " + nThreadID + " is over!"); y-%nJD$  
bDownOver = true; k?o^5@b/  
//nPos = fileAccessI.write (b,0,nRead); &|s+KP|d  
} &K+  
catch(Exception e){e.printStackTrace ();} ^@M[t<  
} O<4Q$|=&?  
} i
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//打印回应的头信息 hx*HY%\P  
public void logResponseHead(HttpURLConnection con) `i=JjgG@  
{ Ft)t`E'%j  
for(int i=1;;i++) qo)Q}0  
{ j p
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String header=con.getHeaderFieldKey(i); *1\z^4=a]  
if(header!=null) 1V-=$Q3 V7  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); C2CYIok$&  
Utility.log(header+" : "+con.getHeaderField(header)); <%M\7NDWDA  
else 5?Uo&e  
break; Tt{U"EFO  
} A*rZQh b[  
} -)4uYK*  
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public void splitterStop() Po'-z<}wS  
{ +ylxez
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bStop = true; }Q!h ov  
} Q^*G`&w,  
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} |sA4:Aq  
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/* rny@n^F  
**FileAccess.java q1U&vZ3]c  
*//文件访问(定位，写) i:V0fBR[>  
package NetFox; rn5"o8|  
import java.io.*; : :F!   
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public class FileAccessI implements Serializable{ 17WNJ  
7vii9Am7  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 h9w@oRp`~  
RandomAccessFile oSavedFile;
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long nPos; n33JTqX  
 KYnW7|*  
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public FileAccessI() throws IOException !S~,>,y
d  
{ O3_D~O ."  
this("",0); I++W0wa.n  
} z0T`5NG@  
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public FileAccessI(String sName,long nPos) throws IOException ^t\kLU  
{ @`w'   
oSavedFile = new RandomAccessFile(sName,"rw"); `V]egdO  
this.nPos = nPos; =nJOaXR0  
oSavedFile.seek(nPos); S1D9AcK  
} ExNj|*  
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public synchronized int write(byte[] b,int nStart,int nLen) a"`g"ZRx  
{ Iq4Kgc  
int n = -1; 3S[w'  
try{ T^/Gj|N*  
oSavedFile.write(b,nStart,nLen); }ZEfT]  
n = nLen; X@6zI-Y%  
} ke3HK9P;  
catch(IOException e) q`/amI0  
{ 7sQ]w   
e.printStackTrace (); 1$='`@8I  
} '#cT4_D^lI  
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return n; pRQfx^On  
} zCKy`u.  
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} XBfiaj  
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/* ;kyL>mV{  
**SiteInfoBean.java &%f]-=~  
*/ 5XSxQG@k^z  
package NetFox; {V]Qwz)1  
]MqH13`)A  
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public class SiteInfoBean { @e.OU(Bf  
jV,(P$ 5;  
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private String sSiteURL; //Site's URL T3u5al  
private String sFilePath; //Saved File's Path j61BP8E  
private String sFileName; //Saved File's Name M`9orq<  
private int nSplitter; //Count of Splited Downloading File }#\;np  
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public SiteInfoBean() 'f=)pc#&g  
{//nSplitter的缺省值为5 Ckl7rpY+  
//default value of nSplitter is 5 0@sr NuW  
this("","","",5); V7B=
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} fG8}=xH_&  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) #q~3c;ec  
{ *!r\GGb  
sSiteURL= sURL; :Fi%Cef|  
sFilePath = sPath; IS0HV$OI  
sFileName = sName;
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this.nSplitter = nSpiltter; zJG x5JC  
.WL\:{G8;  
 =BqaGXr  
} 5I8FD".i  
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F9u:8;\@`  
public String getSSiteURL() rB.=f[aX[  
{ I9:G9  
return sSiteURL; >?G|Yz*kEJ  
} 9z|>roNe  
L6[rvM|9_  
L5zG0mC8  
public void setSSiteURL(String value) DK@w^ZW6JA  
{ e~t}z_>F  
sSiteURL = value; :"<B@Z  
} 6PzN>+t^y  
7/^TwNsv  
~q8V<@?  
public String getSFilePath() Zv1Bju*y  
{ BqLtTo?'  
return sFilePath; BuEQ^[Ex  
} -KIVnV=&m  
A<YZBR_  
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public void setSFilePath(String value) (jo(bbpj  
{ 86^ZY
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sFilePath = value; ]df9'\  
} 9a
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:bM$;  
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public String getSFileName() RXx?/\~yd;  
{ qa0JQ_?o]  
return sFileName; r_g\_y7ua  
} Cb@S </b  
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public void setSFileName(String value) _ntW}})K  
{ 7>#L  
sFileName = value; ~G{$P'[  
} WnJLX ^;  
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#)PGQ)(  
public int getNSplitter() MOqA$b  
{ i"sYf9,  
return nSplitter; cT>z  
} U3_yEvZ  
}<\65 B$1  
\6`%NhkM_  
public void setNSplitter(int nCount) ?2<6#>(7a  
{ Ltic_cjYd?  
nSplitter = nCount; $Va]vC8?  
} }lNufu  
} H%NLL4&wu  
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/* :`>+f.)  
**Utility.java Z z;<P  
*/ #hE3~+i  
package NetFox; o$blPTN  
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 jC/JiI  
public class Utility { (;2J(GZ:$U  
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public Utility() @rK>yPhf  
{ Z'EO  
/qkIoF2  
X,!OWz:[  
} sen{f^U  
~gi( 1<#  
//线程睡眠 L$TKO,T  
public static void sleep(int nSecond) d"d)<f   
{ %\{?(baOA  
try{ Eps\iykB  
Thread.sleep(nSecond); tFST.yT>zg  
} bJ,=yB+0  
catch(Exception e) eZ.0,A*1B1  
{ MY<!\4/  
e.printStackTrace (); AXU!-er$  
} Acq>M^E3  
} ^0ZKHR(}e  
xwH|ryfs,Z  
//日志 6dS1\Y  
public static void log(String sMsg) ZnhuIAAG  
{ KEVy%AP=*h  
System.err.println(sMsg); rd
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} F{H0
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W'
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public static void log(int sMsg) R:IS4AaS  
{ |v%RjN  
System.err.println(sMsg); l3pW{p  
} 9y|&T  
} Fx88R!  
In9|n^=H@  
jVFRqT%  
/* Hj4w i|  
**TestMethod.java p4t!T=o/  
*/ ^a#&wW  
package NetFox; Q0"F>%Cn  
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public class TestMethod { (Q]Y> '  
4\'81"ei  
vzrD"  
public TestMethod() q(ET)xCeD  
{ ///xx/weblogic60b2_win.exe pffw5Tc  
try{ ZLio8  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); MoR-8vnJ  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ~lalc ^  
SiteFileFetch fileFetch = new SiteFileFetch(bean); <,cIc]eX  
fileFetch.start(); "1`i]Y\'  
} M Xt +  
catch(Exception e){e.printStackTrace ();} ]S2[eS  
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} gK#fuQ$hH  
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public static void main(String[] args) L+ETMk0  
{ gZ>orZL'  
new TestMethod(); w4MMo  
} & Dl
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} ND9>`I5  
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