http断点续传简单实现（java)

/* h*Y);mc$#  
**SiteFileFetch.java ( {H5k''  
*/ :sBg+MS  
package NetFox; n@xDFa  
import java.io.*; +]Y&las  
import java.net.*; +t
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public class SiteFileFetch extends Thread { vb}; _/#?  
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SiteInfoBean siteInfoBean = null; //文件信息Bean "}]1OL SV  
long[] nStartPos; //开始位置 pCNihZ~  
long[] nEndPos; //结束位置 M ,8r{[2  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 D!~-53f@  
long nFileLength; //文件长度 x(z[S$6Y\  
boolean bFirst = true; //是否第一次取文件 ~3.
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boolean bStop = false; //停止标志 I#kK! m1Q  
File tmpFile; //文件下载的临时信息 *Ri?mEv hF  
DataOutputStream output; //输出到文件的输出流 .foM>UOY  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） >yn%.Uoh@  
public SiteFileFetch(SiteInfoBean bean) throws IOException d9[*&[2J|  
{ elZ?>5P$}  
siteInfoBean = bean; F+_4Q  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); PqIGc  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); H>[1DH#b  
if(tmpFile.exists ()) QtQku1{  
{ +n]U3b  
bFirst = false; 8| zR8L  
read_nPos(); ;5A&[]@^^@  
} a2*WZc
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else {
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{ dx@#6Fhy  
nStartPos = new long[bean.getNSplitter()];
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nEndPos = new long[bean.getNSplitter()]; !Ljs
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} #:Di1I9<O7  
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} d+%1q
 
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public void run() 1<^"OjQ  
{ /J8AnA1  
//获得文件长度 86~HkHliv  
//分割文件 /!UuGm  
//实例FileSplitterFetch phUno2fH  
//启动FileSplitterFetch线程 0yXUVKq3  
//等待子线程返回 Zbxd,|<|  
try{ -Xkdu?6Eh  
if(bFirst) 28-6(oG  
{ *~fZ9EkD  
nFileLength = getFileSize(); |^Z1 D TAw  
if(nFileLength == -1) <oPo?r|oM|  
{ VY@uQ#&A  
System.err.println("File Length is not known!"); /g712\?M4  
} rSB"0W7  
else if(nFileLength == -2) Ywt_h;:  
{ 8UoMOeI3  
System.err.println("File is not access!"); cn=~}T@~Z  
} l2=.;7IV  
else 3~BL!e,  
{ }#q9>
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for(int i=0;i<nStartPos.length;i++) *8U+2zgfC  
{ b/'fC%o,  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); t/_w}  
} -c%GlpZw  
for(int i=0;i<nEndPos.length-1;i++) 52tIe|KwL  
{ R
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nEndPos = nStartPos[i+1]; =V_}z3b  
} $# @G!  
nEndPos[nEndPos.length-1] = nFileLength; N- ?U2V  
} 3`J?as@^8  
} Xcicqywe?  
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//启动子线程 1#Dpj.cO#  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; _$0<]O$  
for(int i=0;i<nStartPos.length;i++) jwTb09  
{ D*`|MzlQ  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ;or(:Yoc-  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), `Ten2(D  
nStartPos,nEndPos,i); Wk'KN o  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); k _hiGg  
fileSplitterFetch.start(); 18Pc4~>0  
} =XJ SE+ 7  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Q0!gTV  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); J:'c
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// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", WO)rJr!C  
nEndPos = " + nFileLength); 6t TLyI$+  
// fileSplitterFetch[nPos.length-1].start(); r`i<XGPJ%  
-Duy:C6W  
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//等待子线程结束 &m`1lxT  
//int count = 0; vML01SAi  
//是否结束while循环 ,2[laJ  
boolean breakWhile = false; u1ggLH!U  
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/lm;.7_J+  
while(!bStop) K-)_1  
{ q>%KIBh(  
write_nPos(); wtetB')yD  
Utility.sleep(500); B=7bQli}  
breakWhile = true; q+3Z3v  
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for(int i=0;i<nStartPos.length;i++) f3|ttUX  
{ L"1UUOKy  
if(!fileSplitterFetch.bDownOver) m7^aa@^m  
{ z;GnQfYG  
breakWhile = false; $=4T# W=m  
break; nu}$wLM  
} PNd]Xmv)  
} O!lZ%j@%  
if(breakWhile) R?Ki~'k=  
break; B+iVK(j'[v  
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//count++; J8J~$DU\Gv  
//if(count>4) iRS )Z)  
// siteStop(); ?zQ\u{]=  
} c\-5vw||b  
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System.err.println("文件下载结束！"); K\nN2y  
} d47b&.v8e  
catch(Exception e){e.printStackTrace ();} 5.]+K<:h"A  
} v
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//获得文件长度 ^L+*}4Dr  
public long getFileSize() b>hNkVI  
{ =;
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int nFileLength = -1; H`njKKdR  
try{ 7UejK r  
URL url = new URL(siteInfoBean.getSSiteURL()); m(s(2wq"f  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); G`8gI)$u  
httpConnection.setRequestProperty("User-Agent","NetFox"); iP~5=  
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int responseCode=httpConnection.getResponseCode(); '~VKH}b  
if(responseCode>=400) %UI.E=`n  
{ Lz2wOB1Zc+  
processErrorCode(responseCode); *j?tcxq
 
return -2; //-2 represent access is error ?!U=S=8  
} }BKEz[G(  
2S&e!d-  

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String sHeader; 4{(uw  
X,IjM&o"Y  
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for(int i=1;;i++) ^rfY9qMJr8  
{ [!]a' T#x  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); L$cNxz0$  
//Utility.log(in.readLine()); #M$[C d I$  
sHeader=httpConnection.getHeaderFieldKey(i); Jor>YB`X  
if(sHeader!=null) -ZlBg~E  
{ zIi|z}WJ  
if(sHeader.equals("Content-Length")) TUIj-HSe  
{ bTHKMaGWC  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); c$rkbbf~V  
break; 0Jm6 r4s?  
} KiT>W~  
} ,aeQXI#@  
else 8;ke,x  
break; S(
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} ~YA* RCe  
} \{t#V ~  
catch(IOException e){e.printStackTrace ();} a*$to/^r  
catch(Exception e){e.printStackTrace ();} mvO!Y
 
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Utility.log(nFileLength); _7'9omq@  
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return nFileLength; 0;2i"mzS\  
} :'91qA%Wr  
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mcy\nAf5%  
//保存下载信息（文件指针位置） L3JFQc/oh~  
private void write_nPos() Yz=(zj  
{ OXe+=Lp<  
try{ |!E>
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output = new DataOutputStream(new FileOutputStream(tmpFile));
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output.writeInt(nStartPos.length); n$ $^(-g@)  
for(int i=0;i<nStartPos.length;i++) lqn7$
 
{ 
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// output.writeLong(nPos); veAg?N<c p  
output.writeLong(fileSplitterFetch.nStartPos); RbzSQr>a\  
output.writeLong(fileSplitterFetch.nEndPos); /:3:Ky3  
} HS XS%v/Y  
output.close(); f]`#BE)V  
} n0F.Um  
catch(IOException e){e.printStackTrace ();} FRd!UqMXY  
catch(Exception e){e.printStackTrace ();} (+68s9XS7  
}
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//读取保存的下载信息（文件指针位置） u~[HC)4(0  
private void read_nPos() fuSfBtLPR#  
{ ^e:C{]S=  
try{ +%Q:  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ,A`d!{]5  
int nCount = input.readInt(); 0{^vqh.La  
nStartPos = new long[nCount]; 1rKKph  
nEndPos = new long[nCount]; u\wdb^8ds  
for(int i=0;i<nStartPos.length;i++) T]Z|Wq`bot  
{ s:3 altv  
nStartPos = input.readLong(); #"-?+F=rk  
nEndPos = input.readLong(); 5Ds/^fA  
} l*>t@:2J  
input.close(); 'KB\K)cD=3  
} 6zh<PETa03  
catch(IOException e){e.printStackTrace ();} lffp\v{w  
catch(Exception e){e.printStackTrace ();} Hy^Em  
} ;*1bTdB5a  
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private void processErrorCode(int nErrorCode) ?j;e/r.  
{ (MhC83|?  
System.err.println("Error Code : " + nErrorCode); &IsQgS7R  
} =M'M/vKD  
PLU8:H@X  
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//停止文件下载 bP\0S@1YL  
public void siteStop() A'r 3%mC  
{ E9z^#@s  
bStop = true; =y-L'z&r  
for(int i=0;i<nStartPos.length;i++) CF"$&+s9  
fileSplitterFetch.splitterStop(); rCfr&>nn  
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} %|E'cdvkX  
} _Z?{&k  
//负责部分文件的抓取 `q|&;wP.  
**FileSplitterFetch.java mAMi-9  
*/ **_`AM~  
package NetFox; D,q=?~  
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import java.io.*; Go~bQ2*'(/  
import java.net.*; BC*vG=a  
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public class FileSplitterFetch extends Thread { D FDC'E  
^,u0kMG5l  
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String sURL; //File URL sqTBlP  
long nStartPos; //File Snippet Start Position Ay)q %:qx  
long nEndPos; //File Snippet End Position :K
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int nThreadID; //Thread's ID R}Pw#*B  
boolean bDownOver = false; //Downing is over [M>Md-pj  
boolean bStop = false; //Stop identical :*bv(~FW  
FileAccessI fileAccessI = null; //File Access interface %x@ D i`
;  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException %pj6[x`@  
{ PN9^ sLx=  
this.sURL = sURL; u.;zz'|  
this.nStartPos = nStart; ^kZfE"iE2  
this.nEndPos = nEnd; "<o[X
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nThreadID = id; M S 3?#b  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 +Go(yS  
} :$k':0 n  
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public void run() 5\93-e  
{ VD}8ei  
while(nStartPos < nEndPos && !bStop) J)1:jieQ  
{ RtVy^~=G  
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try{ H`u8}{7  
URL url = new URL(sURL); ~RcI+jR)  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); KHwzQ<Z3  
httpConnection.setRequestProperty("User-Agent","NetFox"); AA][}lU:5  
String sProperty = "bytes="+nStartPos+"-"; z_qy>  
httpConnection.setRequestProperty("RANGE",sProperty); ~\= VSwJ  
Utility.log(sProperty); [A$5~/Q{U1  
&v!=\Fig4  
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InputStream input = httpConnection.getInputStream(); FTM(y CN  
//logResponseHead(httpConnection); Jf\lnJTyU8  
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byte[] b = new byte[1024]; W:Rs 0O  
int nRead; @L^Fz$S
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while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) .d< +-w2Mu  
{ <viIpz2jh%  
nStartPos += fileAccessI.write(b,0,nRead); u@|izRk  
//if(nThreadID == 1) aE}1~`  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); u\YH,  
}  V|=PaO  
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Utility.log("Thread " + nThreadID + " is over!"); DLMG<4Cd~  
bDownOver = true; e$F]t*)Xa  
//nPos = fileAccessI.write (b,0,nRead); z;1y7W!v  
} =Y`P}vI]w%  
catch(Exception e){e.printStackTrace ();} Rz}?@zh_8  
} n}==
 
} p.K
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//打印回应的头信息 KTn,}7vZ  
public void logResponseHead(HttpURLConnection con) 8 vNgePn  
{ ~;
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for(int i=1;;i++) +EJwWDJ!%  
{ +|.}oL^}G  
String header=con.getHeaderFieldKey(i); RZ)sCR  
if(header!=null) B5J!&suX  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); QS2J271E}  
Utility.log(header+" : "+con.getHeaderField(header)); [?)=3Pp  
else Gd
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break; gLv|Hu7  
} `abQlBb*  
} g*b 4N_  
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public void splitterStop() KDwz!:ye  
{ ht
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bStop = true; d_9
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} Hj ]$  
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} f`<j(.{9F
 
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gr %8 O-n  
/* I(BG%CO9  
**FileAccess.java tq=1C=h  
*//文件访问(定位，写) dDH+`;$.  
package NetFox; F\1nc"K/(  
import java.io.*; f])?Gw  
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public class FileAccessI implements Serializable{ }aYm86C]  
9@AGx<S1  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 @k~?h=o\b  
RandomAccessFile oSavedFile; ToNi<~  
long nPos; 8?] :>  
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public FileAccessI() throws IOException D^Dm, -  
{ <'A>7M~h?*  
this("",0); ?7-#iC`  
} pM~Xh ]/  
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public FileAccessI(String sName,long nPos) throws IOException 7SzY0})<U  
{ K#M h  
oSavedFile = new RandomAccessFile(sName,"rw"); g!n1]- 1  
this.nPos = nPos; ,oe e'  
oSavedFile.seek(nPos); )gd
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} || ?B1  
5A1oZ+C#  
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public synchronized int write(byte[] b,int nStart,int nLen) EQPZV K/  
{ Sp)KtMV  
int n = -1; SCeZt [  
try{ RAKQ+Y"nl  
oSavedFile.write(b,nStart,nLen); aKs!*uo0H  
n = nLen; FtN1ZZ"<*  
} ~\dpD  
catch(IOException e) >_M}l@1  
{ >V(>2eD'S  
e.printStackTrace (); .jMm-vox}  
} mFayU w  
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return n; #1Mk9sxo  
} EZ #UdK_  
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} :b>Z|7g?  
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1=#r$H  
/* $oE 4q6b  
**SiteInfoBean.java dgssX9g37  
*/ L*tXy>&b.  
package NetFox; kN9S;o@)  
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&n<jpMB  
public class SiteInfoBean {
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x$CpUy{6  
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private String sSiteURL; //Site's URL ,r5<v_  
private String sFilePath; //Saved File's Path r0G#BPgdR  
private String sFileName; //Saved File's Name d_J?i]AP|'  
private int nSplitter; //Count of Splited Downloading File iMx+y5O  
Y=X"YH|  
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public SiteInfoBean() ;t%L(J  
{//nSplitter的缺省值为5 |PH]0.m5  
//default value of nSplitter is 5 !~UI~-i'  
this("","","",5); OfTcF_%  
} xmKa8']x  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) B2d$!Any  
{ >0 !J]gK  
sSiteURL= sURL; 4\pA^%73  
sFilePath = sPath; d1e'!y}R5  
sFileName = sName; &o"Hb=k<  
this.nSplitter = nSpiltter; }=A6Jv(j  
zq!2);,  
$Fz/&;KX!  
} ([|5(Omd\  
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public String getSSiteURL() ?y<n^`  
{ XeDU ,  
return sSiteURL; 3+A 0O%0*  
} t)XV'J  
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public void setSSiteURL(String value) 6?*iIA$b  
{ dMGu9k~u  
sSiteURL = value; 3\=8tg p  
} HKOJkbVZ2^  
u MzefRN  
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public String getSFilePath() n_Um)GI>  
{ u;J=g  
return sFilePath; \(T;@r  
} :#TJ-l:#  
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9Z*`{  
public void setSFilePath(String value) R5]R pW=G  
{ %h
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sFilePath = value; #PXl*~PrQ/  
} |D]jdd@!a2  
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public String getSFileName() KH pxWq  
{ {w!}:8p
 
return sFileName; b@YSrjJ  
} rA=F:N 2  
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@2
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public void setSFileName(String value) [-
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{ qgZ(o@\  
sFileName = value; !
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} d,<ctd  
!LIWoa[ F.  
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public int getNSplitter() w-/bLg[L?$  
{ 2gt08\  
return nSplitter; Fg#*rzA  
} }d.R=A9L
 
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; UrwK  
public void setNSplitter(int nCount) DVSYH{U4  
{ SNK+U"Q  
nSplitter = nCount; AZl=w`;/O%  
} Q|5wz]!5Y(  
} (|U+(~PJ  
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/* _"WQi}
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**Utility.java `n^jU92  
*/ qk_ s"}sS  
package NetFox; bO2$0!=I  
?WAlW,H>  
$%1[<}<  
public class Utility { Q8:u1$
}  
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public Utility() 8:s3Q`O  
{ Z]SCIU @+  
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} Hlz4f+#I  
$wN'mY  
//线程睡眠 m k -" U7;  
public static void sleep(int nSecond) v0$6@K;M4G  
{ f2{4Y)  
try{ }WCz*v1Wq  
Thread.sleep(nSecond); 2o\\qEYg  
} up:e0di{  
catch(Exception e) o.Cj+`0}5  
{ .mok.f<G_m  
e.printStackTrace (); m%Ef]({I  
} 2&tGJq-E  
} u|QfCwQ  
6eS#L21*  
//日志 :=i0$k<E/  
public static void log(String sMsg) /au\OBUge  
{ q1?2 U<  
System.err.println(sMsg); x7NxHTL  
} RIJBHOa  
q!AS}rV  
|xf%1(Rl@  
public static void log(int sMsg) tS!~>X  
{ gcv,]v8  
System.err.println(sMsg); N}dJ)<(2~  
} pg>P]a{  
} -9aht}Z  
'm2,7]  
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/* <c\aZ9+V  
**TestMethod.java B]Zsn`n  
*/ LG,RF:
 
package NetFox; e,4!/|H:  
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public class TestMethod { N`zHe*=[~  
g:2/!tujL  

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public TestMethod() Zy!\=-dSm  
{ ///xx/weblogic60b2_win.exe ~Yr.0i.W  
try{ (>8fcQUBb  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); T.(SBP  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); xE)pj|  
SiteFileFetch fileFetch = new SiteFileFetch(bean); o<g (%ncr  
fileFetch.start(); )E4COw+  
} <=7p~ i5  
catch(Exception e){e.printStackTrace ();} IvO3*{k,  
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2#E;5UYu  
} *uv\V@0  
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public static void main(String[] args) d9^=
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{ pixI&iQ  
new TestMethod(); ' l!QGKz  
} fe0 Y^vW  
} &c\8`# 6  
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