http断点续传简单实现（java)

/* */]1?M@P)  
**SiteFileFetch.java rI:]''PR  
*/ F7p`zf@O]  
package NetFox; X bV?=  
import java.io.*; =F*{O=  
import java.net.*; 0Oq5;5  
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public class SiteFileFetch extends Thread { v|kL7t)}  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ,"5p=JX`  
long[] nStartPos; //开始位置 [yAR%]i
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long[] nEndPos; //结束位置 <>1*1%m  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 U&tR1v'  
long nFileLength; //文件长度 :;x#qtv~Iz  
boolean bFirst = true; //是否第一次取文件 K)oN^  
boolean bStop = false; //停止标志 iu,Bmf^oD  
File tmpFile; //文件下载的临时信息 _`94CC:  
DataOutputStream output; //输出到文件的输出流 )3_g&&  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） X?"Ro`S  
public SiteFileFetch(SiteInfoBean bean) throws IOException *r3u=oWb  
{ hmd,g>J:<  
siteInfoBean = bean; U#_rcu  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); +%RXV~  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); |c>A3 P$=B  
if(tmpFile.exists ()) Q ?W6  
{ jZY9Lx8o  
bFirst = false; >
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read_nPos(); Y-,1&$&
 
} *SZ*S%oS3  
else fx4X!(w!B  
{ I-q@@!=  
nStartPos = new long[bean.getNSplitter()]; <tTn$<b  
nEndPos = new long[bean.getNSplitter()]; cYTX)]^u  
} ex2*oqAdX  
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} "|"bo5M:   
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public void run() Im_`q\i  
{ MgLz:2 :F  
//获得文件长度 qx/GioPU  
//分割文件  /m*v
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//实例FileSplitterFetch uEuK1f`  
//启动FileSplitterFetch线程 Fx0<!_tY-  
//等待子线程返回 [OsW  
try{ >b/0i$8  
if(bFirst) L*VGdZ
 
{ ;z7iUke0%  
nFileLength = getFileSize(); 'bg%9}  
if(nFileLength == -1) 9W7H",
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{ B)
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System.err.println("File Length is not known!"); ~c3CyOab  
} ZAii"F  
else if(nFileLength == -2) o*QhoDjc  
{ ^f1}:g  
System.err.println("File is not access!"); @*l}2W  
} Oox5${#^  
else !/$BXUrd  
{ 5,qfr!hN,  
for(int i=0;i<nStartPos.length;i++) &e%y|{Y  
{ Wm.SLr,o0  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); rq6(^I  
} p2
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for(int i=0;i<nEndPos.length-1;i++) I)O-i_}L&K  
{ cEw/F0  
nEndPos = nStartPos[i+1]; {N;XjV1x  
} 5kJ>pb$/  
nEndPos[nEndPos.length-1] = nFileLength; Md[nlz  
} ?(U> )SvF  
} U1rh[A>  
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//启动子线程 9!FV.yp%F  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; zYj8\iER  
for(int i=0;i<nStartPos.length;i++) Q_1EAxt  
{ Vo(d)"m?  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), +]|J  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 8F4#
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nStartPos,nEndPos,i); nS'0i&<{1  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); w];t]q|  
fileSplitterFetch.start(); iygdX2  
} 8'#%7+ "=!  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), R{6.O+j`  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Tj*zlb4  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", -D.6@@%Kc}  
nEndPos = " + nFileLength); JT<Ia  
// fileSplitterFetch[nPos.length-1].start(); >1mCjP  
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//等待子线程结束 Khw!+!(H  
//int count = 0; IEeh)aj[  
//是否结束while循环 Q:kpaMA1P  
boolean breakWhile = false; %r~TMU2"  
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while(!bStop) I[
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{ 35jP</  
write_nPos(); s
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Utility.sleep(500); F/RV{} 17E  
breakWhile = true; [N#2uo  
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for(int i=0;i<nStartPos.length;i++) 9[6*FAFJPP  
{ rxCuV  
if(!fileSplitterFetch.bDownOver) ^X0<ZI  
{ lcIX l&  
breakWhile = false; 59T:{d;~  
break; S]{K^Q),  
} 18ci-W#p  
} ybf`7KEP2A  
if(breakWhile) GXRK+RHuBi  
break; =`vUWO
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Fv5@-&y$W  
//count++; XF{}St~(  
//if(count>4) 31YzTbl[H  
// siteStop(); )Cyrs~  
} }QG6KJh_%  
HHoh//(\  
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System.err.println("文件下载结束！"); WRFzb0;01  
} D,1S-<  
catch(Exception e){e.printStackTrace ();} uj;-HN)6  
} <tgJ-rnL  
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//获得文件长度 ,n~H]66n  
public long getFileSize() A*
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{ &gcKv1a\  
int nFileLength = -1; i6(y Bn  
try{  +<AX 0(  
URL url = new URL(siteInfoBean.getSSiteURL()); `;4zIBJ  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); t~ Q{\!  
httpConnection.setRequestProperty("User-Agent","NetFox"); 0rA&_K[#-<  
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int responseCode=httpConnection.getResponseCode(); 0sk*A0HX-  
if(responseCode>=400) )UZ 's>O  
{ oXV  
processErrorCode(responseCode); ~n|*-rca  
return -2; //-2 represent access is error ],&WA?>G  
} hq$:62NYg  
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String sHeader; Uq0RJ<n  
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for(int i=1;;i++) m[Px|A5{  
{ x"5/1b3aq  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); XrtB&h|C  
//Utility.log(in.readLine()); }N*6xr*X+  
sHeader=httpConnection.getHeaderFieldKey(i); i@Q)
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if(sHeader!=null) 4wMKl6mL  
{ -&D~TL#  
if(sHeader.equals("Content-Length")) "F}anPY  
{ x:"_B  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); :kflq  
break; T
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} q9yY%  
} ^cDHyB=v4d  
else .0cm mpUNq  
break; W<u63P  
} $ ;~G  
} P0DvZV8  
catch(IOException e){e.printStackTrace ();} _)zSjFX9  
catch(Exception e){e.printStackTrace ();} HpuHJ#l  
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Utility.log(nFileLength); 5A Vo#}&\  
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return nFileLength; VL
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} *pyi;  
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//保存下载信息（文件指针位置） 73rr"> 9#0  
private void write_nPos() S3`zB?7,  
{ ke
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try{ 0^5SL/2  
output = new DataOutputStream(new FileOutputStream(tmpFile)); `\(Fax  
output.writeInt(nStartPos.length); 7?qRY9Qu  
for(int i=0;i<nStartPos.length;i++) uf^"Y3  
{ 89U<9j   
// output.writeLong(nPos); P+wV.pF|  
output.writeLong(fileSplitterFetch.nStartPos); Wb68")$  
output.writeLong(fileSplitterFetch.nEndPos); yfnqu4Cn  
} uK="#1z cC  
output.close(); +k
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}
}aR
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catch(IOException e){e.printStackTrace ();} 959&I0=g"  
catch(Exception e){e.printStackTrace ();} J}hi)k  
} G5Y 8]N  
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//读取保存的下载信息（文件指针位置） e 9U\48  
private void read_nPos() T8JM4F  
{ Gyw@+
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try{ `QC{}Oo^  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); n1a;vE{!  
int nCount = input.readInt(); ~*ZB2  
nStartPos = new long[nCount]; L8Z[Ly+_  
nEndPos = new long[nCount]; 8tK8|t5+  
for(int i=0;i<nStartPos.length;i++) /KO!s,Nk  
{ s{2BG9s
 
nStartPos = input.readLong();
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nEndPos = input.readLong(); l&dHH_m3  
} yrs![u  
input.close(); u7UqN  
} pj6Q0h)  
catch(IOException e){e.printStackTrace ();} Ge8&_7  
catch(Exception e){e.printStackTrace ();} /Tv=BXL-  
} uB>NwCL
;  
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private void processErrorCode(int nErrorCode) -P]J:7*0?\  
{ M3Q#=yy$D$  
System.err.println("Error Code : " + nErrorCode); G9<pYt{:  
} 403%~  
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//停止文件下载 vHZw{'5y  
public void siteStop() K8$Hg:Ky-/  
{ !Ui3}  
bStop = true; f9cS^v_:  
for(int i=0;i<nStartPos.length;i++) E<1^i;F  
fileSplitterFetch.splitterStop(); c BQ|mA  
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} ?"$W=*P\o  
} Wct +T,8  
//负责部分文件的抓取 L"rL
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**FileSplitterFetch.java y/K%F,WMf  
*/ @]1E~  
package NetFox; VjS %!P  
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import java.io.*; l!ltg
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import java.net.*; Hv>A$x$q  
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public class FileSplitterFetch extends Thread { h6}oRz9=g  
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String sURL; //File URL )#l &F$  
long nStartPos; //File Snippet Start Position m0t5oO  
long nEndPos; //File Snippet End Position [
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int nThreadID; //Thread's ID *,-)4)7d  
boolean bDownOver = false; //Downing is over : FF:{&d  
boolean bStop = false; //Stop identical wh l)^D  
FileAccessI fileAccessI = null; //File Access interface ;Z:z'';Lm  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException *YZ'Uy?  
{ 41>Bm*if  
this.sURL = sURL; :Qh5ZO&G0  
this.nStartPos = nStart; NDgl
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this.nEndPos = nEnd; CsS0(n(x  
nThreadID = id; 0I* ^VGZ  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Z`v6DfK}  
} O66\s q  
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public void run() 2/RK pl &  
{
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while(nStartPos < nEndPos && !bStop) G'q7@d{'  
{ <~!7?ak  
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try{ RX4O1Z0  
URL url = new URL(sURL); )/PvaL  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Hq8<g$  
httpConnection.setRequestProperty("User-Agent","NetFox"); zh2$U dZ|M  
String sProperty = "bytes="+nStartPos+"-"; TKvUBy  
httpConnection.setRequestProperty("RANGE",sProperty); yc8FEn!)&  
Utility.log(sProperty); =\e}fyuK  
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}P#%aE&-  
InputStream input = httpConnection.getInputStream(); X0^gj>GI|  
//logResponseHead(httpConnection); b[$%Wg  
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byte[] b = new byte[1024]; $]:I1I  
int nRead; k$y(H;XA  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) [4]lAxrRF  
{ d{0b
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nStartPos += fileAccessI.write(b,0,nRead); @riCR<fF  
//if(nThreadID == 1) DKm`  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 9Gfm?.O5  
} 1el?f>  
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Utility.log("Thread " + nThreadID + " is over!"); @4^5C-  
bDownOver = true; L^yQb4$&M  
//nPos = fileAccessI.write (b,0,nRead); E D*=8s2  
} Ij(S"P@  
catch(Exception e){e.printStackTrace ();} YN_#x  
} RQWVjF#  
} t }
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//打印回应的头信息 " E72j.  
public void logResponseHead(HttpURLConnection con) 5s8S;Pb]<  
{ 3hab51J  
for(int i=1;;i++) k:4 Zc3  
{ >};,Byv!%  
String header=con.getHeaderFieldKey(i); ~` @dI  
if(header!=null) e'[T5HI  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); *#;8mM  
Utility.log(header+" : "+con.getHeaderField(header)); yZ~<! 5.P  
else EXH{3E54)`  
break; h>sz@\{  
} "5 PP<A,F(  
} n{d}]V@  
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q#LwM]<.@>  
public void splitterStop() 7s;<5xc  
{ Y;6<AIx>  
bStop = true; 5'@J}7h  
} [&|Le;h  
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} (9*s:)zD-  
@ \J RxJ  
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/* Wy@Z)z?  
**FileAccess.java q~p,A>K  
*//文件访问(定位，写) "h_]it};C  
package NetFox; zwR@^ 5^6  
import java.io.*; Wv_5sPqLW  
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public class FileAccessI implements Serializable{ V]L$
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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 tBtJRi(  
RandomAccessFile oSavedFile; nT`NfN  
long nPos; </t_<I0{  
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public FileAccessI() throws IOException 'G>Ejh@t  
{ x5v^@_: jr  
this("",0); *h1Zqb  
} WGN[`D"  
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public FileAccessI(String sName,long nPos) throws IOException H.uflO  
{ hghtF  
oSavedFile = new RandomAccessFile(sName,"rw"); B, xrZs  
this.nPos = nPos; L$zT
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oSavedFile.seek(nPos); W=5+k0Q
 
} JmrQDO_(  
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public synchronized int write(byte[] b,int nStart,int nLen) B h@R9O<  
{ "M v%M2'c  
int n = -1; _t6siB_u  
try{ THJ KuWy  
oSavedFile.write(b,nStart,nLen); cx|[P6d  
n = nLen; j8zh^q  
} EhEn|%S
 
catch(IOException e) ABNsi$]r0  
{ -le:0NUwI  
e.printStackTrace (); LnZ*,>1Z  
} /4#.qq0\{c  
F){f{-@)  
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return n; vxUJ4|Qz  
} yZHQql%J O  
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} 4v3
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/* *`ehI_v :  
**SiteInfoBean.java V J){@  
*/ &|%z!x6f  
package NetFox; h?.6e9Y4  
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+ h`:qB  
public class SiteInfoBean { Z@ h<xo*r  
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private String sSiteURL; //Site's URL EYGJDv(S  
private String sFilePath; //Saved File's Path TnL%_!V!  
private String sFileName; //Saved File's Name MgHyKn'rL  
private int nSplitter; //Count of Splited Downloading File WaWT 5|A  
{ YJ.BWr  
Xu3^tH-b<  
public SiteInfoBean() _M:)x0("  
{//nSplitter的缺省值为5 tFwQ /  
//default value of nSplitter is 5 \b.2f+;3  
this("","","",5); eQcy'GA06  
} A&$!s)8z  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) mb0${n~fz  
{ cIl^5eE^Pq  
sSiteURL= sURL; ;ZjQy,H%  
sFilePath = sPath; j0=`Jf  
sFileName = sName; wa<@bub  
this.nSplitter = nSpiltter; J2aA"BhdC"  
n.$<D
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} gD=s~DgN)  
bT[Q:#GL  
m oFK/5cJ  
public String getSSiteURL() z9h`sY~  
{ 'QeqWn  
return sSiteURL; 5y=X?hF~)  
} iA^w2K  
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public void setSSiteURL(String value) 6 Y&OG>_\  
{ '
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sSiteURL = value; n9bX[+#d  
} ji A$6dZU  
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public String getSFilePath() b ";#qVv C  
{ 8C,?Ai<ro  
return sFilePath; "kP.Kx!  
} L2{tof  
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public void setSFilePath(String value) E'XFn'  
{ e{=7,DRH<  
sFilePath = value; RF6(n8["MW  
} J'@I!Jc  
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public String getSFileName() gQ?>%t]  
{
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return sFileName; q n=6>wP  
} gjo\gP@  
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public void setSFileName(String value) bI]1!bi]i  
{ Q=e?G300#L  
sFileName = value; 71K6] ~<  
} ]PUyX8'~  
s4~c>voQB  
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public int getNSplitter() ik&loM_  
{ ,Oxdqxu7  
return nSplitter; @Z3b
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} 6K`frt
 
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public void setNSplitter(int nCount) mXhr: e  
{ E8%O+x}  
nSplitter = nCount; _$cQAH0 E  
} 1-w1k^e  
} #7Qn\C2  
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/&kZ)XOi  
/* (6 0,0|s  
**Utility.java BAm{Gb  
*/ &]#D`u  
package NetFox; j:<E=[Kl  
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public class Utility { -(:BkA  
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public Utility() 3c9v~5og4  
{ &2QN^)q  
m{b(^K9}  
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} \BJnJk!%  
w'L;`k;Q  
//线程睡眠 &X|z(vSJ$  
public static void sleep(int nSecond) {jk {K6 }  
{ [;|g2\  
try{ <~: g  
Thread.sleep(nSecond); _^SNI~  
} X-n'?=  
catch(Exception e) m1+DeXR_g  
{ W9eR3q  
e.printStackTrace ();
_ZR2?y-M  
} bZ3CJ f&mE  
} |$1j;#h  
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//日志 anl?4q3;9  
public static void log(String sMsg) k U3] eh\I  
{ Ma{|+\Q.Z  
System.err.println(sMsg); oO= 6Kd+T  
} 1%1-j  
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&<!I]:Y  
public static void log(int sMsg) >TL0hBaaR  
{ VaQ}XM  
System.err.println(sMsg); 4AP<mo  
} :=~([oSNW"  
} >@rp]xx  
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/* qPzgGbmD9  
**TestMethod.java *B3` #t  
*/ JNMZn/  
package NetFox; 2OK%eVba  
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public class TestMethod { )ZiJl5l@  
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public TestMethod() u
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{ ///xx/weblogic60b2_win.exe 6J&L5E  
try{ xY_/CR[,  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); "I+wU`AIek  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); yYF80mnJz  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ;PLby]=O  
fileFetch.start(); -ud!j  
} /B1NcRS  
catch(Exception e){e.printStackTrace ();} r--"JO%
2  
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} [kC-g
@  
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public static void main(String[] args) FQ O6w'  
{ 53l9s<bOQ  
new TestMethod(); :r#FI".qx  
} a2p<HW;)m  
} (wbG0lu  
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