http断点续传简单实现（java)

/* R>|{N9  
**SiteFileFetch.java pp?D7S  
*/ m[osg< CR_  
package NetFox; @)F)S7  
import java.io.*; eSn+B;  
import java.net.*; 1y&\5kB  
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public class SiteFileFetch extends Thread { -]Bq|qTH[(  
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SiteInfoBean siteInfoBean = null; //文件信息Bean b#c:u2  
long[] nStartPos; //开始位置 &N9 a<w8+  
long[] nEndPos; //结束位置 Yu/ID!`Z  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 krxo"WgD  
long nFileLength; //文件长度 OG~gFZr)6  
boolean bFirst = true; //是否第一次取文件 n)/z0n!\  
boolean bStop = false; //停止标志 r+!YIk  
File tmpFile; //文件下载的临时信息 \
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DataOutputStream output; //输出到文件的输出流 -/B+T>[nTb  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） uh_RGM&  
public SiteFileFetch(SiteInfoBean bean) throws IOException *tFHM &a  
{ "s-"<&>a(  
siteInfoBean = bean; a~`eQ_ND  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); k8yE
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tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Eh`7X=Z7E  
if(tmpFile.exists ()) Ufj`euY  
{ m,28u3@r  
bFirst = false; ;]puq  
read_nPos(); _RYxD"my  
} %Qgw7p4  
else l9~e". ~'  
{ h8j.(  
nStartPos = new long[bean.getNSplitter()]; OnziG+ak  
nEndPos = new long[bean.getNSplitter()]; $p8xEcQdU#  
} T~?Ff|qFC  
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} [^n.Pns  
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public void run() >=lC4Tu  
{ YDsb3X<0'  
//获得文件长度 ;V_e>TyG  
//分割文件 GAzU?a{S  
//实例FileSplitterFetch H'5)UX@LP  
//启动FileSplitterFetch线程 eIF5ZPSZi  
//等待子线程返回 ?,Xw[pR  
try{ je-!4r,  
if(bFirst) y1DL,%j  
{ B IEO,W|  
nFileLength = getFileSize(); +480 l}  
if(nFileLength == -1) ,pfG  
{ M^Yh|%M  
System.err.println("File Length is not known!"); R{4^t97wH{  
} #Pau\|e_  
else if(nFileLength == -2) uc{Ihw  
{ g/_5unI}u  
System.err.println("File is not access!"); !TH) +zi  
} Kn{4;Xk\  
else 3NqB <J  
{ \\ij(>CI  
for(int i=0;i<nStartPos.length;i++) :G=fl)!fE  
{ Ny7S  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 5I;&mW`1,`  
} /<k/7TF`  
for(int i=0;i<nEndPos.length-1;i++) (/YHk`v2  
{ <nf@U>wlw  
nEndPos = nStartPos[i+1]; ]
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} m~ABC#,2  
nEndPos[nEndPos.length-1] = nFileLength; wm@@$  
} .LZ?S"z$w  
} h*
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//MUeTxR  
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//启动子线程 sdrfsrNvB-  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; %0?
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for(int i=0;i<nStartPos.length;i++) xu%k~4cB,  
{ 9RL`<,Q  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), aK~8B_5k8  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 8`{:MkXP  
nStartPos,nEndPos,i); (m}'4et~L  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); a!SiX  
fileSplitterFetch.start(); pF
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} }&D WaO]J7  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), {WS;dX4  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); uMv,zO5  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", bWS&Yk(  
nEndPos = " + nFileLength); FxY}m  
// fileSplitterFetch[nPos.length-1].start(); lFj]4  
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E=Bf1/c\  
//等待子线程结束 RC"MdcD:]y  
//int count = 0; :,7hWs
 
//是否结束while循环 ttQGo
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boolean breakWhile = false; {fM'6;ak  
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while(!bStop) )q4[zv9  
{ B-Hrex]  
write_nPos(); #%2rP'He  
Utility.sleep(500); UDFDJm$  
breakWhile = true; R w\gTo  
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for(int i=0;i<nStartPos.length;i++) ]N]!o#q}L  
{ gVuFHHeUz  
if(!fileSplitterFetch.bDownOver) n8[!pH~6  
{ %2{ye  
breakWhile = false; Q{>k1$fkV  
break; T763
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} ?j.,Nw4FC  
} R\f+SvE  
if(breakWhile) 3,w_".m`#  
break; H8jpxzXv  
1GRCV8"Z^  
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//count++; J)>c9w  
//if(count>4) _LnpnL:  
// siteStop(); .Efk
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} v1JzP#  
~ Iuf}D;  
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System.err.println("文件下载结束！"); s8Q 5ui]  
} :-Z2:
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catch(Exception e){e.printStackTrace ();} qR{=pR  
} hfTY.  
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//获得文件长度 gQuw1  
public long getFileSize() [|L<_.8  
{ B6 ;|f'e!  
int nFileLength = -1; 0+ '&`Q
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try{ j (d~aqW  
URL url = new URL(siteInfoBean.getSSiteURL()); =qIp2c}Rx  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); B$K=\6o  
httpConnection.setRequestProperty("User-Agent","NetFox"); Q&;9x?e  
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int responseCode=httpConnection.getResponseCode(); EZGIf/ 3  
if(responseCode>=400) *^4"5X@  
{ eByz-,{P  
processErrorCode(responseCode); e*C(q~PQ  
return -2; //-2 represent access is error JQI: sj  
} q;CiV  
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String sHeader; J@'wf8Ub  
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for(int i=1;;i++) 3 i0_hZ  
{ BWrxunHO  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); BU_nh+dF  
//Utility.log(in.readLine()); AT3Mlz~7#  
sHeader=httpConnection.getHeaderFieldKey(i); kzLsoZ!I  
if(sHeader!=null) X_h}J=33Q  
{ cT,sh~
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if(sHeader.equals("Content-Length")) bE..P&"  
{ m s\}  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); {
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break; =T@1@w  
} )
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} <'*LRd$1  
else 0~S^
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break; ;^*W+,4WB  
} *)Zdz9E'1(  
} u#.2w)!D  
catch(IOException e){e.printStackTrace ();} x;d6vBTUb  
catch(Exception e){e.printStackTrace ();} 6{b>p+U  
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Utility.log(nFileLength); oPM96 (  
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return nFileLength; T
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} i.m^/0!  
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//保存下载信息（文件指针位置） TeM|:o  
private void write_nPos() QW
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{ lo+A%\1  
try{ Xv^
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output = new DataOutputStream(new FileOutputStream(tmpFile)); i/4>2y9/F4  
output.writeInt(nStartPos.length); tD)J*]G  
for(int i=0;i<nStartPos.length;i++) ga+dt  
{ y)@wjH{6  
// output.writeLong(nPos); K0>zxqY  
output.writeLong(fileSplitterFetch.nStartPos); !|(NgzDP/  
output.writeLong(fileSplitterFetch.nEndPos); N6:`/f+A>T  
} 1+s;FJ2}  
output.close(); sgFEK[w.y  
} k,*XG$2h  
catch(IOException e){e.printStackTrace ();} *2l7f`K  
catch(Exception e){e.printStackTrace ();} 0H:X3y+  
} WsB?C&>x  
7[)E>XRE  
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//读取保存的下载信息（文件指针位置） ktIFI`@w)  
private void read_nPos() UK!(G  
{ !Uo4,g6r+  
try{ $UwCMPs X  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ]f_p8?j"  
int nCount = input.readInt(); bt?5*ETA  
nStartPos = new long[nCount]; ~xFkU#  
nEndPos = new long[nCount]; z{QqY.Gu{G  
for(int i=0;i<nStartPos.length;i++) W=?<<dVYD  
{ ?J0y|  
nStartPos = input.readLong(); z24q3 3O  
nEndPos = input.readLong(); 2?Vd5xkt  
} 'g\4O3&_  
input.close(); _[BP0\dPW  
} /n&&Um\  
catch(IOException e){e.printStackTrace ();} jP.
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catch(Exception e){e.printStackTrace ();} 5 qA'  
} TWTb?HP  
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private void processErrorCode(int nErrorCode) i%?*@uj  
{ YmG("z  
System.err.println("Error Code : " + nErrorCode); $`8wJf9@w  
} ]SEZaT  
LS[]=Mk@1  
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//停止文件下载 QT}tvm@PMq  
public void siteStop() <P<z N~i9j  
{ .%-8 t{dt  
bStop = true; c+ie8Q!  
for(int i=0;i<nStartPos.length;i++) X?Q4}Y  
fileSplitterFetch.splitterStop(); h";L  
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} :`sUt1Fw.  
} hy!3yB@  
//负责部分文件的抓取 HzJz+ x:  
**FileSplitterFetch.java ]?4hyN  
*/ Fr-SvsNFB  
package NetFox; 7tp36TE  
3so%gvY.'  
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import java.io.*; zt%Mx>V@  
import java.net.*; WIGi51yC.x  
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public class FileSplitterFetch extends Thread { 8P`"M#fI  
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String sURL; //File URL *qq+jsA6wH  
long nStartPos; //File Snippet Start Position XWw804ir  
long nEndPos; //File Snippet End Position Zd+bx*rD  
int nThreadID; //Thread's ID
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boolean bDownOver = false; //Downing is over Hn:Crl y#  
boolean bStop = false; //Stop identical b.938#3,  
FileAccessI fileAccessI = null; //File Access interface <UCl@5g&  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException O6Y0XL  
{ 9+N-eW_U  
this.sURL = sURL; :T~[  
this.nStartPos = nStart; EQ_aa@M7  
this.nEndPos = nEnd; h+,@G,|D  
nThreadID = id; gqR(.Pu  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 :Dp0?&_  
} F'Z,]b'st3  
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)
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public void run() lhJ'bYI  
{ uAk.@nfiEv  
while(nStartPos < nEndPos && !bStop) p ll)Y  
{ $[|mGae  
*1"+%Z^  
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try{ 9YGY,sx  
URL url = new URL(sURL); Y/oHu@ _  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); +C)~bb*  
httpConnection.setRequestProperty("User-Agent","NetFox"); XPPdwTOr  
String sProperty = "bytes="+nStartPos+"-"; X3& Jb2c2  
httpConnection.setRequestProperty("RANGE",sProperty); 1~gCtBRM  
Utility.log(sProperty); PY'2h4IL  
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InputStream input = httpConnection.getInputStream(); !x)R=Z/C  
//logResponseHead(httpConnection); k7^5Bp8=  
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byte[] b = new byte[1024]; /{2,zW  
int nRead; kxCSs7J/  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) a9Vi];  
{ Y0> @vTUX  
nStartPos += fileAccessI.write(b,0,nRead); zm# ?W  
//if(nThreadID == 1) iow"n$/  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Ul#
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} $VR{q6[0S?  
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Utility.log("Thread " + nThreadID + " is over!"); XP}<N&j  
bDownOver = true; A}w/OA97RO  
//nPos = fileAccessI.write (b,0,nRead); ?A0)L27UE&  
} sos5Y}  
catch(Exception e){e.printStackTrace ();} E`J@hl$N  
} 6~+
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} |[lKY+26:{  
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//打印回应的头信息 BLFdHB.$T  
public void logResponseHead(HttpURLConnection con) 8,|kao:  
{ I 6O  
for(int i=1;;i++) g{LP7D;6  
{ )PZT4jTt  
String header=con.getHeaderFieldKey(i); V~
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if(header!=null) d=^z`nt !R  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ~Gw*r\\+  
Utility.log(header+" : "+con.getHeaderField(header)); 3XKf!P  
else 1mJHued=6  
break; sRf
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} zeRyL3fnmb  
} m+9#5a-  
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public void splitterStop() hGrdtsH?  
{ Zd&S@Z  
bStop = true; ('~LMu_  
} @nf
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`u\n0=go  
} M%#e1"n  
31)&vf[[  
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/* d5d@k  
**FileAccess.java `h;[TtIX4  
*//文件访问(定位，写) TZ`SZDc7_  
package NetFox; 6:2vP NF  
import java.io.*; rlD8D|ZG  
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\NC3'G:Ii  
public class FileAccessI implements Serializable{ Mihg:  
P;*(hY5&  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 :EyD+!LJ  
RandomAccessFile oSavedFile; E"0>yl)  
long nPos; >d6|^h'0  
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.(vwIb8\_  
public FileAccessI() throws IOException %)wjR/o  
{ Hv, LS;W  
this("",0); 45oR=Atn  
} ^}r1;W?n  
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public FileAccessI(String sName,long nPos) throws IOException 28nFRr  
{ SAz   
oSavedFile = new RandomAccessFile(sName,"rw"); =">NQ)98u  
this.nPos = nPos; 9FX-1,Jx  
oSavedFile.seek(nPos); ~s{$WL&  
} svSVG:48  
E'8;
10s  
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public synchronized int write(byte[] b,int nStart,int nLen) g78^9Y*1  
{ E.f%H(b  
int n = -1; cZ06Kx..  
try{ W8<%[-r  
oSavedFile.write(b,nStart,nLen); ,vDbp?)'U  
n = nLen; d'2A,B~_*  
} HTtnXBJ)*H  
catch(IOException e) saAF+H/=  
{ YS ][n_  
e.printStackTrace (); qWw=8Bq  
} o(HbGHIP  
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 @8 6f  
return n; A=4OWV?  
} /
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} xkn;,`t^lJ  
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/* Ls%MGs9PI  
**SiteInfoBean.java w(rE`IgW  
*/ _Y!IEAU/#  
package NetFox; 8-i#8'/x  
n|;Im&,  
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public class SiteInfoBean { $u.z*b_yy  
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private String sSiteURL; //Site's URL M}Sv8D]I  
private String sFilePath; //Saved File's Path "oD[v  
private String sFileName; //Saved File's Name $^P0F9~0  
private int nSplitter; //Count of Splited Downloading File ZW}_DT0  
}'.m*#Y  
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public SiteInfoBean() ;aBG,dr}i  
{//nSplitter的缺省值为5 `9 L>*  
//default value of nSplitter is 5 PM+[,H  
this("","","",5); =}*0-\QG  
} <qSC#[xu  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) kFB  
{ vbNBLCwug  
sSiteURL= sURL; 2|L&DF:G  
sFilePath = sPath; PdCEUh\>y  
sFileName = sName; 9my^Y9B  
this.nSplitter = nSpiltter; yw!{MO  
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} $k?>DP4  
Y}/-C3)  
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public String getSSiteURL() : 'c&,oLY  
{ xmG<]WF>E  
return sSiteURL; {FGj]*  
} ""H?gsL[  
hj:,S|  
#?E"x/$Y6  
public void setSSiteURL(String value) 9FvFhY  
{ g*Ph
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sSiteURL = value; '7/)Ot(  
} y^k$Us  
/,dz@  
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public String getSFilePath() S:Hl/:iV  
{ 74u&%Rj  
return sFilePath; <[phnU^ 8  
} yuVs YV@"  
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public void setSFilePath(String value) :+Z%; Dc  
{ =I4lL]>  
sFilePath = value; >Q/Dk7#  
} VQs5"K"  
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#QPjkR|\  
public String getSFileName() qLCR] _*  
{ 2|,VqVb  
return sFileName; C+]I@Go'Tk  
} -} +[  
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~@!bsLSMU  
public void setSFileName(String value) I|OoRq  
{ 92c HwWZ!  
sFileName = value; T+$[eWk"a  
} B[}6-2<>?C  
H.;Q+A,8^  
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public int getNSplitter() @L`jk+Y0vF  
{ K'xV;r7Nt  
return nSplitter; S@Y39  
} 7nSxi+6e  
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5N]
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public void setNSplitter(int nCount) jylD6IT  
{ ye97!nIg@  
nSplitter = nCount; RNL9>7xV  
} "|NI]
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} wq{hF<  
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Q
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/* [KQi.u  
**Utility.java Kq!3wb;  
*/ }b}m3i1  
package NetFox; yVfC-Z  
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public class Utility { _GPe<H  
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public Utility() [ )F<V!  
{ N#]ypl  
f^e)O$N9]  
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} 7=uj2.J6  
iCoX&"lb  
//线程睡眠 "tZe>>I  
public static void sleep(int nSecond) e.%nRhSs3  
{ 8|^7ai[am  
try{ WxDh;*am:  
Thread.sleep(nSecond); "
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} l]vm=7:  
catch(Exception e) _aphkeqd  
{ xk5]^yDp  
e.printStackTrace (); jdN`mosJ  
} YUb_y^B^  
} RCrCs  
;a/E42eN;  
//日志 :0/7,i  
public static void log(String sMsg) #4:?gfIj  
{ o-\[,}T)M  
System.err.println(sMsg); `^vE9nW7  
} km(Po}  
Wqnc{oq|$  
Sz~OX6L  
public static void log(int sMsg) PnTu  
{ +q4O D$}  
System.err.println(sMsg); [^)g%|W  
} OI*H,Z"  
} wkq 
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.}t e
>]A*  
kstIgcI  
/* ?< />Z)
  
**TestMethod.java 3Vwh|1?  
*/ l} /F*  
package NetFox; hxx.9x>ow  
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public class TestMethod { ' QG?nu  
7pd$\$  
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public TestMethod() K'bP@y_cq  
{ ///xx/weblogic60b2_win.exe Z;i:](  
try{ Dv"9qk  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); sK{e*[I>W  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 9x8fhAy}4  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Q8NX)R  
fileFetch.start(); QZs!{sZ  
} 4Ig;3 ^%71  
catch(Exception e){e.printStackTrace ();} 7/H)Az@i45  
uH]OEz\H'  
_w{Qtj~s|  
} KXy6Eno  
$`c:&  
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public static void main(String[] args) +0&/g&a\R  
{ osRy e3  
new TestMethod(); 2T35{Q!=F  
} }6#  
} 1^}+=~  
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