http断点续传简单实现（java)

/* qg9VK'
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**SiteFileFetch.java 6o=Q;Mezl  
*/ HqoCl  
package NetFox; fUa[3)I  
import java.io.*; \R
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import java.net.*; (^mpb  
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public class SiteFileFetch extends Thread { tL}_kK_!  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ZxU3)`O  
long[] nStartPos; //开始位置 5rlZ'>I.  
long[] nEndPos; //结束位置 Fa-F`U@h(m  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 X3l? YA  
long nFileLength; //文件长度 Wj"GS!5  
boolean bFirst = true; //是否第一次取文件 qfa[KD)!aB  
boolean bStop = false; //停止标志 zelM}/d  
File tmpFile; //文件下载的临时信息 ~?<VT k  
DataOutputStream output; //输出到文件的输出流 C*&FApG  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） B0$.oavC  
public SiteFileFetch(SiteInfoBean bean) throws IOException SJ).L.Cm6  
{ ZP;WXB`  
siteInfoBean = bean; <nbc RO.  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); E=L1q)  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ]o2 Z14  
if(tmpFile.exists ()) uG{/yJeU  
{ o6c>sh  
bFirst = false; B(qwTz 51  
read_nPos(); t:yJ~En]=  
} 7xoq:oP-}N  
else t>%+[7?6  
{ R(W}..U0R"  
nStartPos = new long[bean.getNSplitter()]; 8;Eg>_cL:  
nEndPos = new long[bean.getNSplitter()]; 7]lUPLsl  
} <g'0q*qE  
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} [6cf$FS9  
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#s
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public void run() 1}"Prx-  
{ 3"p'WZ>  
//获得文件长度 -i*]Sgese  
//分割文件 $ nHf0.V
1  
//实例FileSplitterFetch hL}AgY@  
//启动FileSplitterFetch线程 EVW\Z 2N.  
//等待子线程返回 CjZIBMGc  
try{ H rI(uZ]  
if(bFirst) Twq,6X-  
{ !1[ZfTX^a  
nFileLength = getFileSize();  re@;6o  
if(nFileLength == -1) +!eh\.u|]  
{ :?f^D,w_B  
System.err.println("File Length is not known!"); c%5Suu(J6  
} T/iZ"\(~w  
else if(nFileLength == -2) Z@6xu;O  
{ ,^@z;xF  
System.err.println("File is not access!"); :@K~>^+U  
} JlhI3`X;/  
else }
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{ "`Y.5
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for(int i=0;i<nStartPos.length;i++) buA/G-<e  
{ 0i~?^sT'  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); bD
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}
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for(int i=0;i<nEndPos.length-1;i++) >\'gIIs  
{ QR{>]I  
nEndPos = nStartPos[i+1]; X{tfF!+iy  
} k293
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nEndPos[nEndPos.length-1] = nFileLength; CMC9%uq  
} 6
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} L&G5 kY`  
Z!*k0<Z  
Hk@LHC  
//启动子线程 37 d-!  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ; ~#uH7k  
for(int i=0;i<nStartPos.length;i++) $\q}A:  
{ 67]!xy  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ".sRi  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), /kNS
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nStartPos,nEndPos,i); yt#~n_  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); UNyk, #4  
fileSplitterFetch.start(); wPxtQv  
}  wkKSL  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ]:svR@E  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); l\HtP7]  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ->`R[k  
nEndPos = " + nFileLength); lX/:e=  
// fileSplitterFetch[nPos.length-1].start(); U[|o!2$  
5v"Sv  
lD6PKZ\RIj  
//等待子线程结束 lt& c/xi_  
//int count = 0; gfQ1p?  
//是否结束while循环 %s ">:  
boolean breakWhile = false; Y InPmR  
s_cur-  
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while(!bStop) n..R'vNj  
{ {~EPP .  
write_nPos(); ')>D*e  
Utility.sleep(500); . 
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breakWhile = true; 5U6b\jxX  
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for(int i=0;i<nStartPos.length;i++) 8y'.H21:;  
{ hE;BT>_dn  
if(!fileSplitterFetch.bDownOver) lS/l iI'Y  
{ U:uFrb,  
breakWhile = false; o "1X8v  
break; =6gi4!hE  
} A$-\Er+f  
} N `[ ?db-%  
if(breakWhile) qqSFy>`P  
break; yny1i9 y  
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+^ `n- m  
//count++; #7=- zda5  
//if(count>4) J }|6m9k!  
// siteStop(); G#j~8`3X  
} t^"8 v3
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bp>M&1^KY  
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System.err.println("文件下载结束！"); T9bUt|  
} }A&
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catch(Exception e){e.printStackTrace ();} ^wz 2e  
} yZc#@R[0  
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//获得文件长度 2*a5pFkb  
public long getFileSize() >1hhz  
{ id[caP=`  
int nFileLength = -1; Fhga^.5U&  
try{ gl 27&'?E*  
URL url = new URL(siteInfoBean.getSSiteURL()); k(M(]y_  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); xM![  
httpConnection.setRequestProperty("User-Agent","NetFox"); Xo3@-D_c!c  
.+&M,% x  
8/R9YiY5*  
int responseCode=httpConnection.getResponseCode(); JC iB;!y  
if(responseCode>=400) a?@lX>Z  
{ BH0s` K"  
processErrorCode(responseCode); 3EH7HW  
return -2; //-2 represent access is error }J $\<ZT  
} #]r'?GN  
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String sHeader; GOD{?#
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for(int i=1;;i++) >Q:h0b_$U  
{ R#ZO<g%'  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ());  vURgR  
//Utility.log(in.readLine()); i5SDy(?r  
sHeader=httpConnection.getHeaderFieldKey(i); DB(!*6#?  
if(sHeader!=null) eVj7%9  
{ 10^FfwRfM  
if(sHeader.equals("Content-Length")) YT6dI"48  
{ G\K!7k`)!  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); slaH2}$xR  
break; a3L-
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} mDO! o  
} b4P
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else ~SS3gLv  
break; A_crK`3  
} 6zI}?KZf
 
} nO#x"  
catch(IOException e){e.printStackTrace ();} KW/LyiP#  
catch(Exception e){e.printStackTrace ();} e xkPu-[W  
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Utility.log(nFileLength); Yr[&*>S  
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return nFileLength; @2;cv?i)  
} U+zntB  
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//保存下载信息（文件指针位置） 3,n"d-  
private void write_nPos() d4p6.3  
{ 1iqgVby  
try{ ]r'D  
output = new DataOutputStream(new FileOutputStream(tmpFile)); .A0fI"
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output.writeInt(nStartPos.length); s6'=4gM  
for(int i=0;i<nStartPos.length;i++) rAE5.Q!u  
{ 0o:R:*  
// output.writeLong(nPos); >dgz/n?:v  
output.writeLong(fileSplitterFetch.nStartPos); -hc8IS
 
output.writeLong(fileSplitterFetch.nEndPos); ^tGAJ_b79  
} &q
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output.close(); DxNob-Fr  
} i0K 2#}=^  
catch(IOException e){e.printStackTrace ();} [0y,K{8t  
catch(Exception e){e.printStackTrace ();} 4@3\Ihv  
} 5=I({=/>  
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//读取保存的下载信息（文件指针位置） 1C{0
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private void read_nPos() oSD=3DQ;  
{ `e<IO_cg  
try{ &uRT/+18W3  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); O}zHkcL  
int nCount = input.readInt(); PiM(QR  
nStartPos = new long[nCount]; @I?,!3`jS  
nEndPos = new long[nCount]; )/@KdEA:  
for(int i=0;i<nStartPos.length;i++) #%k_V+o3  
{ yO7y`;Q(sF  
nStartPos = input.readLong(); `WOoC  
nEndPos = input.readLong(); y EfAa6  
} >^Wpc  
input.close(); \ Y
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} -LR
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catch(IOException e){e.printStackTrace ();} jyW={%&  
catch(Exception e){e.printStackTrace ();} Mb2a;s  
} _ikKOU^8  
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private void processErrorCode(int nErrorCode) %<nGm\  
{ Yq00<kIDJ  
System.err.println("Error Code : " + nErrorCode); E/oLE^yL  
} T90O.]S  
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tqh)yr;  
//停止文件下载 y4jiOhF<d  
public void siteStop() -@>]iBl  
{ W vB]Rs  
bStop = true; 8iY.!.G#|  
for(int i=0;i<nStartPos.length;i++) m<3. X"-  
fileSplitterFetch.splitterStop(); ^-PYP:*  
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}
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} yJC: bD1xi  
//负责部分文件的抓取 rhPv{6Z|7  
**FileSplitterFetch.java ZrEou}z(*  
*/ W)r|9G8T  
package NetFox; >$rH,Er  
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import java.io.*; A]0R?N9wb_  
import java.net.*; 3lWGa7<4Z  
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public class FileSplitterFetch extends Thread { $m5Iv_  
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String sURL; //File URL 81|[Y'f  
long nStartPos; //File Snippet Start Position XkqsL0\  
long nEndPos; //File Snippet End Position SHPDbBS  
int nThreadID; //Thread's ID -!~pa^j  
boolean bDownOver = false; //Downing is over j7g>r/1eE  
boolean bStop = false; //Stop identical +7
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FileAccessI fileAccessI = null; //File Access interface -2}ons(  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException B=W#eu <1  
{ <e 9d5-2  
this.sURL = sURL; uYlyU~M:D  
this.nStartPos = nStart; ~u0<c:C^  
this.nEndPos = nEnd; w8q 2f-K-  
nThreadID = id; )g8Kicox5  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 \>oy2{=;'  
} EVqqOp1$v4  
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public void run() R>Ox(MG  
{ h]i vXF*  
while(nStartPos < nEndPos && !bStop) ^ux'-/  
{ b~<V}tJ  
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try{ dhP")@3K;p  
URL url = new URL(sURL); PL31(!`@d  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); j)ln"u0R^B  
httpConnection.setRequestProperty("User-Agent","NetFox"); #$U/*~m $  
String sProperty = "bytes="+nStartPos+"-"; <M5fk?n,|  
httpConnection.setRequestProperty("RANGE",sProperty); ]T5\LNyN  
Utility.log(sProperty);  Jc]k\U  
#:Q\   
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InputStream input = httpConnection.getInputStream(); p/LV^TQ  
//logResponseHead(httpConnection); k`'*niz  
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byte[] b = new byte[1024]; lOb(XH
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int nRead; @!ja/Y^  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 
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{ /={N^8^=x  
nStartPos += fileAccessI.write(b,0,nRead); /VEK<.,aMv  
//if(nThreadID == 1) hfc~HKLC  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); )3|a_   
} |eye) E:  
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Utility.log("Thread " + nThreadID + " is over!"); )Xt#coagS  
bDownOver = true; ]sP  
//nPos = fileAccessI.write (b,0,nRead); !"hzGgOOX  
} nu|,
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catch(Exception e){e.printStackTrace ();} Ks^wX  
} mL#$8wUdt{  
} 5~[][VV^  
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//打印回应的头信息 i3L2N~:V  
public void logResponseHead(HttpURLConnection con) T.%yeJiE  
{ ]70ZerQ~L  
for(int i=1;;i++) Ne3YhCC>  
{ <wd;W;B  
String header=con.getHeaderFieldKey(i); p7izy$Wc  
if(header!=null) r1=j$G  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); *].qm g%  
Utility.log(header+" : "+con.getHeaderField(header)); qMA";Frt3N  
else d}|z+D  
break; 
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} G%!i="/9  
} >xF&>SDC  
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public void splitterStop() LU@1Gol  
{ `6#s+JA[  
bStop = true; +`$$^x  
} HvZSkq^
  
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} g"c7$  
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/* B"5xs  
**FileAccess.java !HhF*Rlr  
*//文件访问(定位，写) UV{})T*s  
package NetFox; 4? rEO(SZ  
import java.io.*; >@-.rkd(  
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public class FileAccessI implements Serializable{ 7A$mZPKh  
V|awbff:  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 iO18FfM_  
RandomAccessFile oSavedFile; J*:_3Wsy  
long nPos; k;SKQN  
[a~@6*=  
0=40}n&`  
public FileAccessI() throws IOException !tx.2m*5  
{ x'6i9]+r  
this("",0); Qs8yJH`v  
} OCCC' k  
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public FileAccessI(String sName,long nPos) throws IOException T@zp'6\H  
{ wM-H5\9n  
oSavedFile = new RandomAccessFile(sName,"rw"); 1L?W+zMO  
this.nPos = nPos; /_8nZVu  
oSavedFile.seek(nPos); 55Mtjqfp  
} z-sq9Qp&x  
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E4.A$/s8[  
public synchronized int write(byte[] b,int nStart,int nLen) MFWkJbZV  
{ *{p:C  
int n = -1; VrhHcvnZ  
try{ {aK
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oSavedFile.write(b,nStart,nLen); ]zI
Ii%  
n = nLen; iHQ$L# 7  
} t9lf=+%s  
catch(IOException e) N{M25ucAHl  
{ &Rz-;66bN  
e.printStackTrace (); i;IhsKO0R  
} OekE]`~w  
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`
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return n; z|(<Co8#.  
} 34_ V&8  
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} A2P.5EN  
=
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/* |S:erYE,G  
**SiteInfoBean.java TDy$Mv=y  
*/ [.CP,Ly  
package NetFox; |=:hUp Jp  
@zLyG#kHY  
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public class SiteInfoBean { z;N`jqo   
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private String sSiteURL; //Site's URL it-2]N
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private String sFilePath; //Saved File's Path z+zEH9.'  
private String sFileName; //Saved File's Name ^^a%Lz)U  
private int nSplitter; //Count of Splited Downloading File tv: mjS  
BV}sN{  
Tv~Ho&LS  
public SiteInfoBean() %<U0  
{//nSplitter的缺省值为5 WQBV~.<Yv  
//default value of nSplitter is 5 K\mFb  
this("","","",5); aH_
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} W
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PO:sF]5  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) gplrJaH@  
{ ,,7hVw  
sSiteURL= sURL; vRDs~'f  
sFilePath = sPath; J(P'!#z^  
sFileName = sName; >Dz8+y  
this.nSplitter = nSpiltter; $)6M@S  
s'Qmrs a  
d-8{}Q  
} l701$>>  

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x&$8;2&.  
public String getSSiteURL() LKZv#b[h  
{ _{GD\Ai_W  
return sSiteURL; `7.$ A U  
} [fs.D /  
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O(:/&`)  
public void setSSiteURL(String value) \3hFb,/4k  
{ Q@"!uB.e  
sSiteURL = value; GC(QV}9z"  
} zhY]!  
Pj5:=d8z(  
"#h/sAIs  
public String getSFilePath() 9S<V5$}  
{ kPO+M~+n  
return sFilePath; " BU4\QF-  
} =dp`4
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V|/N-3M  
jY ;Hdb''  
public void setSFilePath(String value) c@KNyBy2  
{ ~b%dBn]n>  
sFilePath = value; vtc%MG1  
} i1GQ=@  
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public String getSFileName() b{ tp qNm~  
{ $F]*B `  
return sFileName; =6=l.qyYK  
}
" ^!=e72  
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vorb?iVf>  
public void setSFileName(String value) Ml
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{ n} ]gAX  
sFileName = value; f{|n/j;n=C  
} 7Oi<_b  
]1I-e2Q-J  
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public int getNSplitter() g3Ul'QJ  
{ l(}l([rdQ  
return nSplitter; SjcX|=S  
} ZbH_h]1$D  
:J+ANIRI  
l>("L9  
public void setNSplitter(int nCount) :]LW,Eql  
{ QHtN_
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nSplitter = nCount; FR\r/+n:t0  
} OfeM;)  
} ~$1g"jIw  
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/* {<
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**Utility.java vJ;0%;eu[!  
*/ Ia:M+20n  
package NetFox; q~{O^,4S  
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public class Utility { VI.Cmw~S  
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#=Whh 9-d  
public Utility() 1b@]^Ue  
{ %xC}#RDf  
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} dSS Ai |}  
|WgFLF~k  
//线程睡眠 9q2x}  
public static void sleep(int nSecond) v}@Uc-(  
{ `*B6T7p1  
try{ 8]4W@~c  
Thread.sleep(nSecond); e_FoN
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} QO4eDSW  
catch(Exception e) #zc$cr  
{ (62Sc]  
e.printStackTrace (); 3RI%OCGF  
} c2PBYFCyC  
} EIOP+9zP  
:GM3n$  
//日志 6-\M }xq?  
public static void log(String sMsg) "}0)~,{xB  
{ ^[q/w<_j~  
System.err.println(sMsg); d\tA1&k71  
} 9CZEP0i7  
rt\.|Hr4s  
c >xHaA:V  
public static void log(int sMsg) P[H 4Yp  
{ Qo80u?*  
System.err.println(sMsg); (?P\;yDG  
} =ibKdPtTh^  
} yz%o?%@  
{G=|fgz  
161IWos  
/* $8Gj9mw4e'  
**TestMethod.java &p55Cg@e)  
*/ H$6;{IUz~  
package NetFox; pwNF\ ={  
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k jx<;##R8  
public class TestMethod { y`pgJO  
K>#QC  
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public TestMethod() zo1fUsK?  
{ ///xx/weblogic60b2_win.exe 26=G%F6  
try{ QF$s([  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); \ns} M3  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Rvd'uIJ  
SiteFileFetch fileFetch = new SiteFileFetch(bean);  wKbU}29c  
fileFetch.start(); QGnUPiD
^  
} 5GURfG3{  
catch(Exception e){e.printStackTrace ();} Dt'bbX'edw  
-.5R.~@  
m=60a@o]  
} RvyCc!d  
$Q=S`z=  
jN/snU2\0  
public static void main(String[] args) x}uDW   
{ ]#W9l\  
new TestMethod(); bj@f<f`  
} QvlVjDIy  
} ,2mq}u>WU  
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