http断点续传简单实现（java)

/* _s/5oRHA  
**SiteFileFetch.java dC$z q~q  
*/
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package NetFox; K]{Y >w  
import java.io.*; yF-EHNNf  
import java.net.*; WleE$ ,  
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public class SiteFileFetch extends Thread { (*>%^C?  
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2 5DXJb^:  
SiteInfoBean siteInfoBean = null; //文件信息Bean iYi3x_A`  
long[] nStartPos; //开始位置 wJs#rkW  
long[] nEndPos; //结束位置 7{%_6b"  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 );o2eV  
long nFileLength; //文件长度 ~)XyrKw  
boolean bFirst = true; //是否第一次取文件 u]K&H&AxT  
boolean bStop = false; //停止标志 4NaL#3  
File tmpFile; //文件下载的临时信息 7JvBzD42  
DataOutputStream output; //输出到文件的输出流 %l4LX~-:  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） zO BLF|L=  
public SiteFileFetch(SiteInfoBean bean) throws IOException e5/f%4YX  
{ `52+.*J+%  
siteInfoBean = bean; +yvtd]D$2W  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); !7C[\No(
 
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); R_IUuz$e  
if(tmpFile.exists ()) ,@mr})s  
{ ?RyeZKf  
bFirst = false; &M p??{g  
read_nPos(); =P}ob eY  
} $l05VZ  
else 9Z.Xo kg  
{ 7>#?-, B  
nStartPos = new long[bean.getNSplitter()];
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nEndPos = new long[bean.getNSplitter()]; TPjElBh  
} {z~n`ow  
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}
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public void run() 5f;6BP  
{ zl?Gd4  
//获得文件长度 hk6(y?#  
//分割文件 !&'GWQY{(  
//实例FileSplitterFetch :w|ef;  
//启动FileSplitterFetch线程 [D
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//等待子线程返回 BvQMq5&  
try{ 1b^e4  
if(bFirst) ,sw
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{ ?A4zIJ\  
nFileLength = getFileSize(); N|JML  
if(nFileLength == -1) `fTH"l1zn  
{ "Y%fk/
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System.err.println("File Length is not known!"); '%Cc!63t*  
} :1>h,NKC>  
else if(nFileLength == -2) ;a"g<v  
{ H(L.k;B  
System.err.println("File is not access!"); ?4k/V6n@y  
} .|\}]
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else ~quof>  
{ 'q3<R%^Q   
for(int i=0;i<nStartPos.length;i++) _C`&(?}  
{ z$64Ep#  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); +D7>$&BD  
} x*H,eY3  
for(int i=0;i<nEndPos.length-1;i++) * {avx  
{ 8 5 L<  
nEndPos = nStartPos[i+1]; GkwdBy+  
}
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nEndPos[nEndPos.length-1] = nFileLength; #)}K
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} 7:[u.cd  
} s#Os?Q?  
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//启动子线程 )RUx  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ` nd/N#  
for(int i=0;i<nStartPos.length;i++) 7
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{ [3K& cX}B  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), pc/x&VY%  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), \#50; 8VJ  
nStartPos,nEndPos,i); ~F [V  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); %C[#:>'+  
fileSplitterFetch.start(); WiU-syNh  
} '6g;UOx^=  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), lJHU1 gu  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); @\*`rl]  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", .ZOG,h+8  
nEndPos = " + nFileLength); PJfADB7Y  
// fileSplitterFetch[nPos.length-1].start(); Y0z)5),[U:  
8SZZ_tS3r  
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//等待子线程结束 8}M-b6RV  
//int count = 0; @23?II$=@  
//是否结束while循环 I K9plsd*  
boolean breakWhile = false; ,=a+;D]'  
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while(!bStop) "xI70c{  
{ QLm#7ms*y  
write_nPos(); t6q7w  
Utility.sleep(500); dDg[ry  
breakWhile = true; yac4\%ze  
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for(int i=0;i<nStartPos.length;i++) c9ye[81  
{ 2%?Kc]JY9  
if(!fileSplitterFetch.bDownOver) *KV^X(/  
{ >sm~te$5  
breakWhile = false; w,T-vf  
break; g+j\wvx0  
} 7_9^nDU  
} r@t \a+  
if(breakWhile) 2tw3 =)  
break; 9]L4`.HM  
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(.J6>"K<  
//count++; M!`&Z9N  
//if(count>4) 7VIfRN{5n  
// siteStop(); &q7}HO/ @  
} !#Pr'm/,mu  
{EjzJr>  
SgWLs%B  
System.err.println("文件下载结束！"); +;Pkpuu  
} xeB-fy)5+  
catch(Exception e){e.printStackTrace ();} []-<-TqJ  
} 5_\1f|,  
1rIL[(r4  
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//获得文件长度 !59,<N1Iu  
public long getFileSize() Q<Q?#v7NX  
{ 0 wjL=]X1e  
int nFileLength = -1; 'u#c_m!9  
try{ 5oe{i/#di  
URL url = new URL(siteInfoBean.getSSiteURL()); F2>W{-H+  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection ();  \4j(el  
httpConnection.setRequestProperty("User-Agent","NetFox"); kp-`_sDg  
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int responseCode=httpConnection.getResponseCode(); *kt|CXxAS8  
if(responseCode>=400) ;uho.)%N`F  
{ wii.0~p  
processErrorCode(responseCode); YJ!jdE}  
return -2; //-2 represent access is error FJp<J  
} 7\AoMk}  
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String sHeader; 6{w'q&LYcE  
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for(int i=1;;i++) N^{}Qvrr  
{ _oHxpeM  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); b
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//Utility.log(in.readLine()); %0zp`'3Y  
sHeader=httpConnection.getHeaderFieldKey(i); mKLWz1GZ  
if(sHeader!=null) cte Wl/v  
{ 12V-EG i  
if(sHeader.equals("Content-Length")) M_O)w^ '  
{ ~#dfZa&   
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ^KJi|'B  
break; A6I^`0/  
} +V9(4la  
} 4nXemU=  
else L0R$T=~%)  
break; %KPQ|^WE  
} F@KtRUxE  
} #h#_xh'  
catch(IOException e){e.printStackTrace ();} bt"5.nm  
catch(Exception e){e.printStackTrace ();} "H9q%S,FH  
,*sKr)9)  
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Utility.log(nFileLength); ;*{Ls#  
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return nFileLength; ZkBWVZb  
} QBCEDv&j  
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//保存下载信息（文件指针位置） ?r}2JHvN  
private void write_nPos() ( m7qc  
{ l15Z8hYhj  
try{ 6H!l>@a7v  
output = new DataOutputStream(new FileOutputStream(tmpFile)); yb-4[C:i  
output.writeInt(nStartPos.length); @zJiR{Je-U  
for(int i=0;i<nStartPos.length;i++) wn.UjxX.  
{ xS;tmc  
// output.writeLong(nPos); #"-DE-I[  
output.writeLong(fileSplitterFetch.nStartPos); FP")$ ,=s  
output.writeLong(fileSplitterFetch.nEndPos); Q?bC'147O  
} hG}
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output.close(); ctPT=i60  
} &"=O!t2  
catch(IOException e){e.printStackTrace ();} / <+F/R'=O  
catch(Exception e){e.printStackTrace ();} }&]T0U`@  
} `[h&Q0Du6  
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//读取保存的下载信息（文件指针位置） %v0;1m  
private void read_nPos() ";upu  
{ w3;T]R*  
try{ |+Xh ^E  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); hbSKlb0d  
int nCount = input.readInt(); y"iK)SH  
nStartPos = new long[nCount]; 94?/Rhs5  
nEndPos = new long[nCount]; h(i_'P?  
for(int i=0;i<nStartPos.length;i++) 8g?2( MT;  
{ s~A:*2\  
nStartPos = input.readLong(); F5+!Gb En  
nEndPos = input.readLong(); a :CeI  
} !FQS9SoO9  
input.close(); O' Mma5  
} @P">4xVX{  
catch(IOException e){e.printStackTrace ();} z"*3p8N  
catch(Exception e){e.printStackTrace ();} u63Q<P<  
} As??_=>4  
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private void processErrorCode(int nErrorCode) 2gW+&5;4  
{ EiS2-Uh*TT  
System.err.println("Error Code : " + nErrorCode); z3M6<.K  
} ?[.g~DK,  
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//停止文件下载 
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public void siteStop() M(:_(4~  
{ AgWG4C=  
bStop = true; A{wk$`vH
  
for(int i=0;i<nStartPos.length;i++) >+%p}l:<\  
fileSplitterFetch.splitterStop(); WV;[vg]  
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} PI)uBA;  
} %htbEKWR  
//负责部分文件的抓取 <U}2
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**FileSplitterFetch.java KssIoP
 
*/ zomg$@j  
package NetFox; ;(s.G-9S  
}<q=Zq+  
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import java.io.*; @9g!5dcT  
import java.net.*; ^t[br6G  
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public class FileSplitterFetch extends Thread { &>Z p}.V  
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String sURL; //File URL !H4uc  
long nStartPos; //File Snippet Start Position S/6I9zOP  
long nEndPos; //File Snippet End Position XRn+6fn|  
int nThreadID; //Thread's ID _mDvRFq  
boolean bDownOver = false; //Downing is over R/&C}6Gn  
boolean bStop = false; //Stop identical }S9uh-j6l  
FileAccessI fileAccessI = null; //File Access interface zU# OjvNk  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException t`0(5v  
{ ^ |>)
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this.sURL = sURL; 30h1)nQ$h}  
this.nStartPos = nStart; R[2h!.O8  
this.nEndPos = nEnd; `4"&_ltD  
nThreadID = id; 9-?kamA  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 `(L<Q%  
} e(k$k>?  
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public void run() Ec['k&*7,  
{ 3M{b:|3/q  
while(nStartPos < nEndPos && !bStop) s`,.&  
{ fQ,(,^!;  
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try{ <~Tfi*^+  
URL url = new URL(sURL); 7@i2Mz/eV  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); [oS.B\Vc  
httpConnection.setRequestProperty("User-Agent","NetFox"); JmVha!<
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String sProperty = "bytes="+nStartPos+"-"; ;%PdSG=U  
httpConnection.setRequestProperty("RANGE",sProperty); ]I0(_e|z}  
Utility.log(sProperty); \8SHX
 
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InputStream input = httpConnection.getInputStream(); V
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//logResponseHead(httpConnection); 'p(I!]"uo  
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byte[] b = new byte[1024]; 2n5{H fpY  
int nRead; :6Sb3w5h  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) U_e e3KKA  
{ +yu^Z*_  
nStartPos += fileAccessI.write(b,0,nRead); h>K%OxR  
//if(nThreadID == 1) .e2K\o  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Jx= v6==7  
} "a>a "Ei  
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Utility.log("Thread " + nThreadID + " is over!");
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bDownOver = true; O:G-I$F|  
//nPos = fileAccessI.write (b,0,nRead); !yX4#J(  
} z
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catch(Exception e){e.printStackTrace ();} x^]1m%  
} ppM^&6x^  
} '^.}5be&  
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}g[(h=Qi  
//打印回应的头信息 #oD*H:%*  
public void logResponseHead(HttpURLConnection con) ^k}jPc6  
{ }[I|oV5*+&  
for(int i=1;;i++) ^<O:`c6_  
{ & pS5_x  
String header=con.getHeaderFieldKey(i); {!vz 6QDS  
if(header!=null) Fu!sw]6xx  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); CI6qDh6  
Utility.log(header+" : "+con.getHeaderField(header)); Gu136
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else Qw
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break; z"lRfOWI  
} 1~P ^g`  
} \muC_9ke  
)|@UY(VZ^  
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public void splitterStop() T5di#%: s  
{ 2*1s(Jro  
bStop = true; ~2*8pb 4  
} gT6@0ANq  
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} 0UT2sM$  
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/* a<K@rgQ  
**FileAccess.java f<0nj?  
*//文件访问(定位，写) ~8G<Nw4
*\  
package NetFox; 7|Tu@0XXA  
import java.io.*; o$DJL11E  
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public class FileAccessI implements Serializable{ .v:K`y;f\(  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 W=EvEx^?%  
RandomAccessFile oSavedFile; 3QrYH @7zx  
long nPos; Xpd^^  
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public FileAccessI() throws IOException TBYRY)~f  
{ Pc4FEH/  
this("",0); 3q.O^`y FU  
} L_YVe(dT  
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public FileAccessI(String sName,long nPos) throws IOException *:}NS8hP  
{ <j.bG 7  
oSavedFile = new RandomAccessFile(sName,"rw"); :d<;h:^_  
this.nPos = nPos; Dyj5a($9"{  
oSavedFile.seek(nPos); f9g#pyH4  
} 0iX;%SPYz  
\Podyh/;?  
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public synchronized int write(byte[] b,int nStart,int nLen) O9k9hRE]z  
{ aMFUJrXo
 
int n = -1; n(b(H`1n  
try{ ##!)}i  
oSavedFile.write(b,nStart,nLen); wKCHG/W  
n = nLen; y$At$i>u  
} XY8s\D
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catch(IOException e) 5u\si4BL{  
{ 5"5D(  
e.printStackTrace (); ( {H5k''  
} Rt<8&.m4  
t "J"G@1)  
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return n; 1;[\xqJ  
} o~F @1  
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} "Kz=ZC  
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/* EIwTx:{F  
**SiteInfoBean.java V>j6Juh  
*/ lV-7bZ  
package NetFox; )dJaF#6j  
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 # a 'h,  
public class SiteInfoBean { 9psX"*s  
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9(Vq@.;Z`j  
private String sSiteURL; //Site's URL /}Y>_87  
private String sFilePath; //Saved File's Path [BHf>  
private String sFileName; //Saved File's Name Mrp'wF D  
private int nSplitter; //Count of Splited Downloading File qDO4&NO  
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public SiteInfoBean() PqIGc  
{//nSplitter的缺省值为5 H>[1DH#b  
//default value of nSplitter is 5 QtQku1{  
this("","","",5); +n]U3b  
} ]S
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;5A&[]@^^@  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) {
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{ dx@#6Fhy  
sSiteURL= sURL;
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sFilePath = sPath; !Ljs
9 =UF  
sFileName = sName; #:Di1I9<O7  
this.nSplitter = nSpiltter; |$":7)eH!  
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} 'N],d&fu^^  
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public String getSSiteURL() f8)D|  
{ 8f% @  
return sSiteURL; k'wF+>  
} LQ?J r>4  
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public void setSSiteURL(String value) Wy,DA^\ef  
{ "TKf"z
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sSiteURL = value; 2s;/*<WM  
} C8y 3T/G  
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hZ.Sj~>7`  
public String getSFilePath() _Q/D%7[pa  
{ (^Xp\dyZL  
return sFilePath; kqSCKY1  
} {!x
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&~
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public void setSFilePath(String value) Tn/T:7C  
{ iqghcY)  
sFilePath = value; !'B.ad  
} i)\`"&.j>N  
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public String getSFileName() \CB{Ut+s  
{ LS4c|Dv  
return sFileName; oDx*}[/  
}  o)cd!,h  
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public void setSFileName(String value) /9|1eSUa  
{ )dG7$,g  
sFileName = value; X^?<, Y)1.  
} )m"NO/sJ2  
(zBa2Vmmv  

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public int getNSplitter() 0kpRvdEr-  
{ ?)7uwJsH  
return nSplitter; RP7e)?5$s  
} /+P 4cHv]F  
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*(s+u~, I  
public void setNSplitter(int nCount) Q<d\K(<3?:  
{ 4*lS
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nSplitter = nCount; ,|"tLN*m  
} T^aEx.`O}`  
}
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/* f/?# 1  
**Utility.java 4 Yc9Ij  
*/ vd SV6p.d  
package NetFox; 4<70mUnt  
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public class Utility { S,lJ&Rsu  
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v@LK3S/!3  
public Utility() >yg mE`g  
{ 9cWl/7;zXO  
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]/HSlT=  
} g[44YrRD  
kG &.|  
//线程睡眠
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public static void sleep(int nSecond) X(?.*m@+TB  
{ z6B/H2  
try{ '[~NRKQJ  
Thread.sleep(nSecond); utQE$0F  
} nE+sbfC   
catch(Exception e) *pk*ijdB  
{ r{$ip"f  
e.printStackTrace (); bAeC=?U  
} F5wCl2I  
} _$NFeqLww  
=ILs[p  
//日志 V? w;YTg  
public static void log(String sMsg) 8uM>UpX  
{ :f ybH)*  
System.err.println(sMsg); ,<zGvksk  
} )~T)$TS  
Av^{$9yl  
 3p"VmO  
public static void log(int sMsg) h$DFp  
{ OlK3xdg7  
System.err.println(sMsg); ~+A?!f;-J  
} "L|Ew#  
} @T._   
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/* pB&3JmgR$)  
**TestMethod.java Nlx7"_R"Q  
*/ JaXT B"e  
package NetFox; 75r>~@)*  
VljAAt  
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public class TestMethod { sk\U[#ohH  
1%]|O  
%UI.E=`n  
public TestMethod() Lz2wOB1Zc+  
{ ///xx/weblogic60b2_win.exe *j?tcxq
 
try{ ;RflzY|D  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); :`2<SF^0O  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); fB:9:NX  
SiteFileFetch fileFetch = new SiteFileFetch(bean); hq6fDR
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fileFetch.start(); f'0n^mSP  
} aA-A>z  
catch(Exception e){e.printStackTrace ();} 4!i`9w$$"  
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} L$cNxz0$  
#M$[C d I$  
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public static void main(String[] args) -ZlBg~E  
{ zIi|z}WJ  
new TestMethod(); TUIj-HSe  
} &W-L`aFd0  
} wOOBW0tj  
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