http断点续传简单实现（java)

/* <M(Jqb cWa  
**SiteFileFetch.java Q_ zGs6  
*/ *h+@a  
package NetFox; Pm2T
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import java.io.*; .T*K4m{b0  
import java.net.*; :6~DOvY  
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public class SiteFileFetch extends Thread { OQ[E-%v1 R  
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SiteInfoBean siteInfoBean = null; //文件信息Bean h5+qP"n!?q  
long[] nStartPos; //开始位置 K"p$ga{  
long[] nEndPos; //结束位置 9}~WwmC
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FileSplitterFetch[] fileSplitterFetch; //子线程对象 @x9DV{j)V  
long nFileLength; //文件长度 BXNt@%  
boolean bFirst = true; //是否第一次取文件 >d.o1<  
boolean bStop = false; //停止标志 / v";u)  
File tmpFile; //文件下载的临时信息 Kd2?9gaw  
DataOutputStream output; //输出到文件的输出流 ]_cBd)3P}  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ttEQgkd`  
public SiteFileFetch(SiteInfoBean bean) throws IOException Y^zL}@  
{ Gk'j<a  
siteInfoBean = bean; <SiD m-=E  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 7@[3]c<=  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); d>ltL`xn  
if(tmpFile.exists ()) %9|}H [x  
{ p&B c<+3e  
bFirst = false; Q o}&2m  
read_nPos(); e-$U .cx  
} aE[>^~Lv}  
else z93HTy9  
{ b`x7%?Qn  
nStartPos = new long[bean.getNSplitter()]; 68m
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nEndPos = new long[bean.getNSplitter()]; ('!{kVLT-  
} ' 0iXx   
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} v3b[08 F  
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public void run() l2v4SvbX  
{ 
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//获得文件长度 ;>*l?m-S@n  
//分割文件 OBGA~E;%  
//实例FileSplitterFetch 3t  
//启动FileSplitterFetch线程 E,6(/`0H*  
//等待子线程返回 >Ab>"!/'K  
try{ Yg 8AMi  
if(bFirst) 2ckAJcpEb/  
{ B{fPj9Y0  
nFileLength = getFileSize(); J(BtGGU'  
if(nFileLength == -1) T[mo PD5  
{ !PN;XZ~{  
System.err.println("File Length is not known!"); nC^|83  
} V^O dTM  
else if(nFileLength == -2) [emUyF  
{ j, SOL9yg  
System.err.println("File is not access!"); EJ
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} =bJj;bc'5  
else #;Yn8'a~  
{ u{0'"jVJ  
for(int i=0;i<nStartPos.length;i++) 4"$K66yk@  
{ gu+c7qe  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); =NyN.^bwT  
} uzf@49m]m  
for(int i=0;i<nEndPos.length-1;i++) C-@  
{ -4P2 2  
nEndPos = nStartPos[i+1]; Evd
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} L2s)B  
nEndPos[nEndPos.length-1] = nFileLength; s1,kTde  
} <8UqV.&  
} *9"
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;p~&G"-C`  
//启动子线程 nSH A,c  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; [al,UO  
for(int i=0;i<nStartPos.length;i++) pfj%AP:  
{ d*%-r2K  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), yZf+*j/a7  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), TGnyN'P|  
nStartPos,nEndPos,i); s>Eu[uA  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Dp:u!tdbeg  
fileSplitterFetch.start(); [m*=Q  
} n\v\<mVTb7  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), b6Jv|1w'  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); z/bJDSQ  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", #(o 'G4T  
nEndPos = " + nFileLength); 
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// fileSplitterFetch[nPos.length-1].start(); )|>LSKTEl  
gi::?ET/.  
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//等待子线程结束 pdnkHR$  
//int count = 0; (k?,+jnR  
//是否结束while循环 4l! ^"=rh  
boolean breakWhile = false; +MG(YP/l  
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while(!bStop) 3}::"X  
{ zx7*Bnu0  
write_nPos(); L@*0wx`fU  
Utility.sleep(500); =>ooB/  
breakWhile = true; F(E3U'G  
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for(int i=0;i<nStartPos.length;i++) 0mB]*<x8  
{ *wW/nr=\;  
if(!fileSplitterFetch.bDownOver)
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{ :0BaEqX  
breakWhile = false; 1Yt;1k'  
break; o[AQS`  
} /p~Wk4'  
} 8" Z!: =A  
if(breakWhile) ${n=1-SMU  
break;
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//count++; Ya] qo]  
//if(count>4) V}732?Jy  
// siteStop(); G!~[+B  
} #84p
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System.err.println("文件下载结束！"); ^6v ob  
} O`e0r%SJ  
catch(Exception e){e.printStackTrace ();} DJ"O`qNV3  
} A3%s5`vNvH  
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//获得文件长度 aK'`
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public long getFileSize() jyF0asb  
{ (;=:QjaoZ  
int nFileLength = -1; SJ1 1LF3)  
try{ )L#C1DP#  
URL url = new URL(siteInfoBean.getSSiteURL()); >V:g'[b  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 7*5$=z4,1  
httpConnection.setRequestProperty("User-Agent","NetFox"); gx&BzODPd0  
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int responseCode=httpConnection.getResponseCode(); d)|{iUcW  
if(responseCode>=400) IC}?oXs5G  
{ }zVPdBRfm  
processErrorCode(responseCode); ADRjCk}I
 
return -2; //-2 represent access is error M-KjRl  
} 8;7Y}c  
$3](6  
}fw;{&s{z  
String sHeader; D%cWw0Oq  
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\
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for(int i=1;;i++) *&)<'6  
{ c8mcJAc  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); $NP5Z0v7  
//Utility.log(in.readLine()); ~~]/<d  
sHeader=httpConnection.getHeaderFieldKey(i); GDC`\
cy  
if(sHeader!=null) WAiEINQ^)  
{ 42LlR 0  
if(sHeader.equals("Content-Length")) VAf~,T]Ww  
{ '01H8er  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); |i-Qfpn  
break; xKKL4ws  
} 2A@9jl s  
} {O*<1v9<  
else '2=u<
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break; O4FW/)gq  
} '>> IMF  
} ~*D)L'`2M  
catch(IOException e){e.printStackTrace ();} e!yUA!x`u  
catch(Exception e){e.printStackTrace ();} ?}sh@;]*h  
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Utility.log(nFileLength); ?}%Gr,tj2  
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return nFileLength; Y4`MgP8t  
} NLM ]KT  
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6  
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//保存下载信息（文件指针位置） 'X{cDdS^  
private void write_nPos() L'4o
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{ N)A?*s'v~  
try{ qWe1`.o  
output = new DataOutputStream(new FileOutputStream(tmpFile)); CtVY;eG  
output.writeInt(nStartPos.length); o9M[Zr1@k  
for(int i=0;i<nStartPos.length;i++) ''!pvxA  
{ *!UY;InanX  
// output.writeLong(nPos); 5=Mm=HyI2  
output.writeLong(fileSplitterFetch.nStartPos); WMBntB   
output.writeLong(fileSplitterFetch.nEndPos); <Fb3\T L  
} 70&v
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output.close(); ^[XxE Lx  
} 5gW`;Cdbyc  
catch(IOException e){e.printStackTrace ();} HTI1eLZ2  
catch(Exception e){e.printStackTrace ();} c+AZ(6O?\  
} 1&c>v3 $2  
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//读取保存的下载信息（文件指针位置） Rk^Fasg"  
private void read_nPos() =nOV!!  
{ boo,KhW'Y  
try{ <5/r  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); h{.KPK\  
int nCount = input.readInt(); OlhfBu)~  
nStartPos = new long[nCount]; PRl\W:_t  
nEndPos = new long[nCount]; ed*Cx~rT  
for(int i=0;i<nStartPos.length;i++) joDnjz=  
{ 6cSMKbgZJ  
nStartPos = input.readLong(); @lAOi1m,,  
nEndPos = input.readLong(); b
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} ]CH@T9d5V  
input.close(); v vlfL*f  
} 4NbX!"0  
catch(IOException e){e.printStackTrace ();} S5d:?^PGg  
catch(Exception e){e.printStackTrace ();} RH ow%2D  
} )H$
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private void processErrorCode(int nErrorCode) @``kt*+K+  
{ +Uq9C-Iu  
System.err.println("Error Code : " + nErrorCode); g~.,
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} Y5=~>*e  
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//停止文件下载 +] B  
public void siteStop() *wP8)yv7  
{ %Rr!I:[ $  
bStop = true; ?AP2Opsl  
for(int i=0;i<nStartPos.length;i++) "e g`3v  
fileSplitterFetch.splitterStop(); %@$h?HP  
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}
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} b>E%&sf  
//负责部分文件的抓取
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**FileSplitterFetch.java zy4AFW  
*/ shxr^  
package NetFox; IGT~@);  
(}O)pqZ>  
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import java.io.*; 3/:O8H  
import java.net.*; 0~A<AF*t  
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public class FileSplitterFetch extends Thread { [{N i94:d  
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String sURL; //File URL  wxsJB2  
long nStartPos; //File Snippet Start Position COFs?L.`  
long nEndPos; //File Snippet End Position ]l+Bg;F#V  
int nThreadID; //Thread's ID EVNTn`J_  
boolean bDownOver = false; //Downing is over B+
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boolean bStop = false; //Stop identical )(*A1C[  
FileAccessI fileAccessI = null; //File Access interface Di9yd  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException dJ?VN!B0  
{ Y+iC/pd  
this.sURL = sURL; b@^M|h.Va  
this.nStartPos = nStart; L;nRI.  
this.nEndPos = nEnd; 52m^jT Sx  
nThreadID = id; Q6,rY(b6  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ]?-56c,  
} )]J I Q"rR  
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public void run() &[*_ -  
{ X~0l1 @!  
while(nStartPos < nEndPos && !bStop) |/arxb&  
{ aen(Mcd3bg  
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try{ Cd'P  
URL url = new URL(sURL); 9/}i6j8Z  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); s7I*=}{g0.  
httpConnection.setRequestProperty("User-Agent","NetFox"); :m5& i&  
String sProperty = "bytes="+nStartPos+"-"; )oTEB#J  
httpConnection.setRequestProperty("RANGE",sProperty); 'e3y|  
Utility.log(sProperty); u>&\@?(  
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InputStream input = httpConnection.getInputStream(); V==' 7n  
//logResponseHead(httpConnection); FtM7+>Do
.  
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byte[] b = new byte[1024]; c/;t.+g  
int nRead; Lj*FKP\{  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) }K~JM1(26  
{ <B`}18x  
nStartPos += fileAccessI.write(b,0,nRead); {tOuKnnS  
//if(nThreadID == 1) 68FxM#xR  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 6xdu}l=%  
} FPaj p  
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Utility.log("Thread " + nThreadID + " is over!"); /T#<g:   
bDownOver = true; k%hD<_:p  
//nPos = fileAccessI.write (b,0,nRead); {Hp?rY@  
} OOl{  
catch(Exception e){e.printStackTrace ();} Da-F(^E  
} IL.Jx:(0  
} m6 hA,li  
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//打印回应的头信息 7S] h:q%%  
public void logResponseHead(HttpURLConnection con) nyQFS  
{ WcH^bAY6  
for(int i=1;;i++) <$?:|  
{ -
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String header=con.getHeaderFieldKey(i); +V2a|uvEc  
if(header!=null) rA`zuYo  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); LvWU %
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Utility.log(header+" : "+con.getHeaderField(header)); GZZLX19sq  
else |]GEJUWtCd  
break; yqejd_cd  
} 'Dat.@j  
} LWVO%@)w  
wW%I <M  
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public void splitterStop() T{uktIO/  
{ @;rVB  
bStop = true; ykM#EyN  
} g,,cV+  
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'')G6-c/  
} 7y[B[$P  
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/* ,1~Zqprn  
**FileAccess.java //J:p,AF  
*//文件访问(定位，写) ]G1j\wnF  
package NetFox; t<`ar@}  
import java.io.*; HhqqJEp0  
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public class FileAccessI implements Serializable{ yLDHJ}R  
,7j`5iq[m  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节  fx;5j;  
RandomAccessFile oSavedFile; r#Pd
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long nPos; ..~{cU4Tt  
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public FileAccessI() throws IOException ?5(L.XFm  
{ Fn[~5/  
this("",0); qb"!  
} QlXy9-oJ"  
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public FileAccessI(String sName,long nPos) throws IOException (vI7qD_  
{ R(zsn;  
oSavedFile = new RandomAccessFile(sName,"rw"); wz, \zh  
this.nPos = nPos; wR;l"*
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oSavedFile.seek(nPos); N$y4>
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} EXBfzK)a  
vaQ,l6z .h  
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public synchronized int write(byte[] b,int nStart,int nLen) ~f@<]  
{ BMdr.0  
int n = -1; #t/Q4X +  
try{ &a|oJ'clz  
oSavedFile.write(b,nStart,nLen); TM"-X\e~{  
n = nLen; <=zGaU,  
} #zy%B  
catch(IOException e) 0)P
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{ Fx@ {]  
e.printStackTrace (); :EO}uP2  
} `Ch6"=t  
P\M+ZA ;  
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return n; HhpP}9P;  
} $(NfHIX  
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} kl={L{r  
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/* q@\_q!  
**SiteInfoBean.java sbs"26IE  
*/ .U1dcL6  
package NetFox; Y{O&-5H^|  
p;5WLAF  
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public class SiteInfoBean { pP r<8tm[  
>ciq4H43Q|  
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private String sSiteURL; //Site's URL 7d<v\=J
}  
private String sFilePath; //Saved File's Path z=fag'fzM  
private String sFileName; //Saved File's Name -?]ltn9!  
private int nSplitter; //Count of Splited Downloading File x)?\g{JH  
ms{R|vU%b  
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public SiteInfoBean() E??%)q  
{//nSplitter的缺省值为5 c[YjGx  
//default value of nSplitter is 5 #<~f~{x  
this("","","",5); F9<OKcXH  
} Ya_6Zd4O  
roA1=G\Q  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 4tC_W!?$t  
{ N<{`n;  
sSiteURL= sURL; esHiWHAC  
sFilePath = sPath; xL BG}C  
sFileName = sName; q)~qd$yMS  
this.nSplitter = nSpiltter;
\1Bgs^  
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Y/^<t'o&  
} K$ &wO.  
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{#%xq]r_  
public String getSSiteURL() C
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{ S3_4i;K\  
return sSiteURL; y(dS1.5F  
} Z~uKT n  
br;G5^j3?  
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public void setSSiteURL(String value) md`ToU  
{ ]/bE${W*]  
sSiteURL = value; 8F* WT|]  
} HZm i?  
X2`>@GR/>  
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public String getSFilePath() 2tv40(M:<  
{ `#f=&S?k  
return sFilePath; caP  
} |z'?3?,~  
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public void setSFilePath(String value) (*ng$zZ$  
{ V\"5<>+O  
sFilePath = value; [!le 9aNg  
} jE#8&P~  
CwvNxH#LVu  
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public String getSFileName() k)s 7Ev*  
{ 78)^vvn5~  
return sFileName; k~#|8eLv  
} TJpv"V  
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@QG1\W'  
public void setSFileName(String value) Lm|X5RVq  
{ X2[cR;;'  
sFileName = value; KV_Ga8hs  
} @"8QG^q8de  
!cb#fl  

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public int getNSplitter() J7GsNFL  
{ fYy.>m+P1  
return nSplitter; 6\;1<Sw*  
} ra>`J_  
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public void setNSplitter(int nCount) _w;+Jh  
{ :Y>]6  
nSplitter = nCount; L_mqC(vn  
} G 7]wg>*  
} kDq%Y[6Z  
3(+#^aw  
r%pFq1/'!  
/* k_>{"Rc  
**Utility.java !h!9SE  
*/ ^kvH/Y&  
package NetFox; e
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public class Utility { wG5RN;`V  
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cl{W]4*$  
public Utility() k_<{j0z.  
{ X3{1DY3@u  
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U!:!]DX(  
} oxQID  
_M[[vXH  
//线程睡眠 WgJAr73 l  
public static void sleep(int nSecond) q_y,j&  
{ ;-pvc<_c<  
try{ 'S7@+kJ  
Thread.sleep(nSecond); \Z20fh2
 
} 5w)^~#'  
catch(Exception e) 9jGuelwN  
{ n/oipiYx  
e.printStackTrace (); BddECY,z  
} NcBe|qxQ  
} ^FM9} t/U,  
]H#Rm#q  
//日志 A;-z#R#V5  
public static void log(String sMsg) q'F_j"  
{ yj'' \  
System.err.println(sMsg); 19 wqDIE0  
} <ytKf<a%e  
nX\]i~  
;[%}Xx  
public static void log(int sMsg) }u_EXP8M  
{ Pgw%SMEp  
System.err.println(sMsg); RyOT[J  
} b2X'AHK S  
} 4Sstg57x~  
8o7]XZE=)  
-*hb^MvP  
/* Di<J6xu  
**TestMethod.java `JWYPs
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*/ ]~00=nXFM/  
package NetFox; Cxk$"_  
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cbCE $  
public class TestMethod { NQ!N"C3u  
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public TestMethod() @y0bU*v7  
{ ///xx/weblogic60b2_win.exe E[3
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try{ Mj B<\g>  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Dg>'5`&  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); $wYuH9(  
SiteFileFetch fileFetch = new SiteFileFetch(bean); X!rQ@F3  
fileFetch.start(); 8jjk?PUD8  
} '!^E92  
catch(Exception e){e.printStackTrace ();} N _~KZQ11^  
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q"+ q  
} K>R;~ o  
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public static void main(String[] args) ra%R:xX  
{ w <#*O:  
new TestMethod(); ECS<l*i57&  
} ,/?%y\:J  
} "T{~,'T  
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