http断点续传简单实现（java)

/* )e`$'y@L$  
**SiteFileFetch.java ;LM`B^Q]s  
*/ :G\f(2@  
package NetFox; n!e4"|4~z  
import java.io.*; ;@xSJqT  
import java.net.*; o8c4h<,  
Cc7PhoPK  
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public class SiteFileFetch extends Thread { r=lhYn  
2.6%?E]  
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SiteInfoBean siteInfoBean = null; //文件信息Bean }DiMt4!ZC!  
long[] nStartPos; //开始位置 'B0= "7  
long[] nEndPos; //结束位置 5>M6lwS  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 v?Q&06PMRc  
long nFileLength; //文件长度 WZ`u"t^2V  
boolean bFirst = true; //是否第一次取文件 M:i;;)cq  
boolean bStop = false; //停止标志 Kt5;GUV  
File tmpFile; //文件下载的临时信息 QyN<o{\FD!  
DataOutputStream output; //输出到文件的输出流 <Uf?7  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） W=j  
public SiteFileFetch(SiteInfoBean bean) throws IOException H.#<&5f  
{ R@_i$Df|  
siteInfoBean = bean; |c,,*^  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); uaN0X"  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); (F9U`1~4  
if(tmpFile.exists ()) v.Wkz9 w}  
{ seO7/h_a  
bFirst = false; GqB]^snh  
read_nPos(); R+Q..9P  
} !*#2~$:  
else I[u%kir  
{ G`3/${ti  
nStartPos = new long[bean.getNSplitter()]; AB92R/  
nEndPos = new long[bean.getNSplitter()]; HAJK%zLc  
} $A"C1)d;  
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^ 'W<|  
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} *V}T}nK7  
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public void run() {T EF#iF  
{ AP*Z0OFE  
//获得文件长度 CsfGjqpf  
//分割文件 @ov*Fh  
//实例FileSplitterFetch Hxe!68{aR  
//启动FileSplitterFetch线程 dJ~AMol  
//等待子线程返回 =y)e&bj  
try{ ? I7}4i7  
if(bFirst) >S\D+1PV  
{ fX"cQ&  
nFileLength = getFileSize(); %dA6vHI,  
if(nFileLength == -1) h8#14?  
{ ft
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System.err.println("File Length is not known!"); "SGq$3D  
} );X&J:-l+  
else if(nFileLength == -2) -L=aZPW`M  
{ AG?cI@',  
System.err.println("File is not access!"); S+aXlb  
} ;jC}.] _)w  
else GZ xG!r-  
{ 3^NHVg  
for(int i=0;i<nStartPos.length;i++) WBcnE(zF  
{ h+ixl#:  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); x93t.5E6  
} yb{ud  
for(int i=0;i<nEndPos.length-1;i++) 1
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{ BllS3I}V  
nEndPos = nStartPos[i+1]; =z_.RE  
} iKs @oHW  
nEndPos[nEndPos.length-1] = nFileLength; AXbDCDA  
} @K{1O|V  
} %#5yC|o9Pn  
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//启动子线程 LHit9O[_/s  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; &d1|B`gL|  
for(int i=0;i<nStartPos.length;i++) glk-: #  
{ y;oPg4  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), :zN{>,sC  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), >iE/t$%1  
nStartPos,nEndPos,i); T["(wPrt  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 8n_!WDD  
fileSplitterFetch.start(); ep|>
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} v[-.]b*5A$  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), v D"4aw  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); @D$^- S6  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", )w3?o#@  
nEndPos = " + nFileLength); =8`!Ph@(  
// fileSplitterFetch[nPos.length-1].start(); _[J @w.l(  
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<]{$XcNm  
//等待子线程结束 e,
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//int count = 0; [WZGu6$SU  
//是否结束while循环 !'yCB9]O  
boolean breakWhile = false; VTM*=5|c  
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while(!bStop) G3[X.%g`  
{ v@_^h}h/,=  
write_nPos(); |AgdD  
Utility.sleep(500); j%_{tB  
breakWhile = true; ?%)G%2  
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for(int i=0;i<nStartPos.length;i++) ..Q$q2.  
{ )1E[CIaXK  
if(!fileSplitterFetch.bDownOver) qeM`z  
{ l:' 0  
breakWhile = false; ,q[aV 6kO  
break;
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} d'bAM{R>  
} aXOW +$,  
if(breakWhile) f}1B-  
break; kfb*|  
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//count++; ]6)~Sj$ 5  
//if(count>4) WR5@S&fU`  
// siteStop(); $9~6M*  
} H YA<  
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System.err.println("文件下载结束！"); )\xDo<@  
} >0^oC[ B  
catch(Exception e){e.printStackTrace ();} .N:& {$o:  
}  ~OdE!!  
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nu=yE$BN{  
//获得文件长度 __B`0t  
public long getFileSize()  Rix|LKk{  
{ @ OSSqH  
int nFileLength = -1; wWh)yfPh8H  
try{ .zm/GtOV@  
URL url = new URL(siteInfoBean.getSSiteURL()); M/Twtq-`H  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ON.1'Wk?  
httpConnection.setRequestProperty("User-Agent","NetFox"); AbqeZn  
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int responseCode=httpConnection.getResponseCode(); te<lCD6  
if(responseCode>=400) zYCS K~-GW  
{ JI)@h 4b  
processErrorCode(responseCode); .()|0A B&g  
return -2; //-2 represent access is error 6ct'O**k*&  
} 'MWu2L!F  
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String sHeader; w!G
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for(int i=1;;i++) "A4.2  
{ [5"F=tT7WP  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); sYMgi D  
//Utility.log(in.readLine()); jPDk
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sHeader=httpConnection.getHeaderFieldKey(i); L\GjG&Y5  
if(sHeader!=null) R&vV!d  
{ YA?46[:  
if(sHeader.equals("Content-Length")) $;k2b4u  
{ Oh&k{DWE$  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 6=aXz2.f  
break; !e<D2><^  
} .+.'TY--  
} d?9b6k?  
else /Wx({N'
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break; N(7UlS,u'  
} BQOit.  
} ,NA _pvH)  
catch(IOException e){e.printStackTrace ();} Z)Zc9SVC  
catch(Exception e){e.printStackTrace ();} 6Fe$'TP  
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Utility.log(nFileLength); nt
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return nFileLength; bE6:pGr  
} W Z_yaG$U  
&{
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//保存下载信息（文件指针位置）  mS]&  
private void write_nPos() wf,B/[,d  
{ TF[8r[93  
try{ A0A]#
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output = new DataOutputStream(new FileOutputStream(tmpFile)); LBw$K0  
output.writeInt(nStartPos.length); }w|a^=HAp  
for(int i=0;i<nStartPos.length;i++) DwNEqHi  
{ S.! n35  
// output.writeLong(nPos); W }"n*  
output.writeLong(fileSplitterFetch.nStartPos); ^U8^P]{R|  
output.writeLong(fileSplitterFetch.nEndPos); Mhwuh`v%  
} z,f  
output.close(); wk@S+Q  
} 23iMG]J&  
catch(IOException e){e.printStackTrace ();} }2!=1|}  
catch(Exception e){e.printStackTrace ();} JtbwY@R  
} |ctcY*+  
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//读取保存的下载信息（文件指针位置） ]Jum(1Bo  
private void read_nPos() kc:>[{9  
{ [" PRxl  
try{ VUQx"R9-  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); jqJ't)N  
int nCount = input.readInt(); QIWfGVc-  
nStartPos = new long[nCount]; EyK F5TP0  
nEndPos = new long[nCount]; U=vh_NHj  
for(int i=0;i<nStartPos.length;i++) G@=H=' :~  
{ NGs@z^&V  
nStartPos = input.readLong(); OH_mZA  
nEndPos = input.readLong(); Qw@_.I  
} u|T
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input.close(); ZR*Dl.GWY  
} j96\({;k  
catch(IOException e){e.printStackTrace ();} ,?KN;~t#vz  
catch(Exception e){e.printStackTrace ();} 6E))4 lW  
} 6qF9+r&e?  
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private void processErrorCode(int nErrorCode) Oe_*(q&  
{ `%<^$Ng
;  
System.err.println("Error Code : " + nErrorCode); ~6!TMVr  
} 5f-eWW]!  
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]7/6u.G7R  
//停止文件下载 8w\ZY>d  
public void siteStop() *f*o ,~8V1  
{ WW[G
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bStop = true; )d =8)9B  
for(int i=0;i<nStartPos.length;i++) $
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fileSplitterFetch.splitterStop(); D"vl$BX  
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} rsPo~nA  
} }M|,Z'@*  
//负责部分文件的抓取 6)#=@i` \  
**FileSplitterFetch.java [6}>
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*/ DRy,n)U&  
package NetFox;  jT$  
e:T8={LU2W  
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import java.io.*; L^%jR=  
import java.net.*; NU/:jr.W#  
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public class FileSplitterFetch extends Thread { uk<JV*R=  
_I<LB0kgf.  
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String sURL; //File URL Jr.4Y>;}e3  
long nStartPos; //File Snippet Start Position LR:meCOI  
long nEndPos; //File Snippet End Position o"Mhwh  
int nThreadID; //Thread's ID o4Hp|iK&0  
boolean bDownOver = false; //Downing is over UtzM+7r@  
boolean bStop = false; //Stop identical Z%9_vpWc  
FileAccessI fileAccessI = null; //File Access interface t` f.HJe  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException
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{ /^9KZj  
this.sURL = sURL; ?_BK(kL_  
this.nStartPos = nStart; yRtxh_wr9  
this.nEndPos = nEnd; [7sy}UH  
nThreadID = id; V^D!\)#  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 P;DGs]PF  
} SMIr@*R  
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public void run() :J~sz)n4  
{ wu`P=-
 
while(nStartPos < nEndPos && !bStop) D\9
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{ a%N
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try{ 79G& 0 P\  
URL url = new URL(sURL); 6ntduXeNVh  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ]zUvs6ksLG  
httpConnection.setRequestProperty("User-Agent","NetFox"); g|V
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String sProperty = "bytes="+nStartPos+"-"; HTw7l]]  
httpConnection.setRequestProperty("RANGE",sProperty); s;!Tz)  
Utility.log(sProperty); T$vDw|KSVP  
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InputStream input = httpConnection.getInputStream(); 8TV "9{ n  
//logResponseHead(httpConnection); ]<g`rR
7}  
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byte[] b = new byte[1024]; ['#3GJz-  
int nRead; )a0%62  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ;($"_h  
{ m{{8#@g  
nStartPos += fileAccessI.write(b,0,nRead); F?*ko,  
//if(nThreadID == 1) JR^#NefJ  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); yf@DaIG  
} Unc_e  
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*wNO3tP't  
Utility.log("Thread " + nThreadID + " is over!"); Di>
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bDownOver = true; /+g)J0
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//nPos = fileAccessI.write (b,0,nRead); Kjfpq!NYE  
} iW$f1=i  
catch(Exception e){e.printStackTrace ();} BELx
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} au~}s |#  
}  r]lPXj(`  
4!)=!sL;  
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//打印回应的头信息 o5`LLVif5y  
public void logResponseHead(HttpURLConnection con) = k7}[!T  
{ qEy]Rc%  
for(int i=1;;i++) ;rjd?r  
{ ]^c]*O[8  
String header=con.getHeaderFieldKey(i); 'pQ\BH  
if(header!=null) Bkh1
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//responseHeaders.put(header,httpConnection.getHeaderField(header)); Yfjp:hg/!  
Utility.log(header+" : "+con.getHeaderField(header)); {- Y.C
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else y>jP]LR4  
break; b9cY  
} 9}*<8%PSt,  
} ie9,ye"  
*C"-$WU3o  
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public void splitterStop() JVawWw0q  
{ :0'2m@x~  
bStop = true; )"4v0dv  
} *p=a-s5-  
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} "o6a{KY(  
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/* F!pgec%]'  
**FileAccess.java *!-J"h  
*//文件访问(定位，写) 9W+RUh^W  
package NetFox; KE*8Y4#9  
import java.io.*; 7,:$, bL  
9Atnnx]n  
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public class FileAccessI implements Serializable{ h.WvPZ2U  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 9zs!rlzQ  
RandomAccessFile oSavedFile; u/S{^2`b  
long nPos; &>$+O>c ,  
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(//f"c]/  
public FileAccessI() throws IOException Gr}lr gPS  
{ 3sF^6<E  
this("",0); hCFgZiH2  
} [8$
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public FileAccessI(String sName,long nPos) throws IOException >Ndck2@  
{ #cdrobJ  
oSavedFile = new RandomAccessFile(sName,"rw"); ~;uc@GGo  
this.nPos = nPos; m2h@*  
oSavedFile.seek(nPos); *%;+3SV  
} A1uo@W  
`Eq~W@';Q0  
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public synchronized int write(byte[] b,int nStart,int nLen) NPY\ >pf  
{ f&ri=VJY\T  
int n = -1; ;eQOBGX9  
try{ (m%
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oSavedFile.write(b,nStart,nLen); k
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n = nLen; I2G:jMPy  
} 5i|DJ6  
catch(IOException e) H4{CiZ  
{ G>f2E49BXt  
e.printStackTrace ();  tQSJ"Q  
} >uR0Xs;V  
=QQTHL{3  
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return n; &U7INUL  
} uW4wTAk;qh  
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} .m/$ku{/J  
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/* ]R?{9H|jwE  
**SiteInfoBean.java %f'mW2  
*/ (]gd$BgD
 
package NetFox; :+*q,lX8  

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public class SiteInfoBean { T_3JAH e  
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private String sSiteURL; //Site's URL '"Z\8;5i  
private String sFilePath; //Saved File's Path t'{IE!_  
private String sFileName; //Saved File's Name "`q:
  
private int nSplitter; //Count of Splited Downloading File g+1&liV  
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*JT,]7>  
public SiteInfoBean() Y5,[udF:O  
{//nSplitter的缺省值为5 ":!7R<t  
//default value of nSplitter is 5 NcMohpkq  
this("","","",5); vj,OX~|  
} 43m@4Yb  
6#gS`X23Y  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) mtd ,m  
{ pEp`Z,p  
sSiteURL= sURL; 2*)2c[/0F  
sFilePath = sPath; R&MdwTa  
sFileName = sName; VxA?LS`  
this.nSplitter = nSpiltter; qr<RMs  
kVeR{i<*(  
jRGslak;  
} 734f&2  
0s'h2={iI  
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public String getSSiteURL() z}z 6Vg  
{ s:ZYiZ-  
return sSiteURL; k3yA*Ec  
} =9yh<'583  
T j(MIFi|5  
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public void setSSiteURL(String value) ms%RNxU4:  
{ hteAuz4H  
sSiteURL = value; UYw=i4J'  
} <reALC  
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public String getSFilePath() >K;DBy*  
{ ^Iy'G44  
return sFilePath; 6 @A'N(I=O  
} Mv?$zV"`#  
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public void setSFilePath(String value) ?[VL 2dP0  
{ #
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sFilePath = value; &m=73RN  
} {16]8-pe  
R(AS$<p{!>  
h ]6:`5-  
public String getSFileName() H~:EPFi.(  
{ N5d)&a 7?  
return sFileName; r7^oqEp@B  
} $H8B%rT]  
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public void setSFileName(String value) f>hA+  
{ PK).)5sW  
sFileName = value; d+o.J",E  
} C2}f'  
4H4ui&|7u6  
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public int getNSplitter() E! GH$%:;  
{ J~.`  
return nSplitter; v8
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} =J
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u  
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public void setNSplitter(int nCount) u*=8s5Q[  
{ H!P$p-*.  
nSplitter = nCount; \k 6'[ln  
} H):(8/>(  
} %WF]mF T_  
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b  
*$Z,kZ^^  
/* #IR,KX3]A  
**Utility.java %E2b{Y;  
*/ P
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package NetFox; ^D8~s;?  
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public class Utility { Tx>V$+al
 
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public Utility() s[bQO1g;*  
{ \IaUsx"#o{  
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} WZM  
UR~s\m  
//线程睡眠 ub
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public static void sleep(int nSecond) NHiac(&*  
{ H1.ktG  
try{ rS8}(lf  
Thread.sleep(nSecond); .
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} -v! ;  
catch(Exception e) YeS5%?Fk  
{ s}F.D^^G  
e.printStackTrace (); qV0GpVJZU?  
} wxo*\WLe  
} MY}/h@  
A{p_I<  
//日志 I(H9-!&  
public static void log(String sMsg) Cto>~pV  
{ c] -  
System.err.println(sMsg); 7M)<Sv  
} E#R1
 
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[}HS[($  
public static void log(int sMsg) ik#ti=.  
{ H'+3
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System.err.println(sMsg); !dq$qUl/  
} *ze,
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} #mYe@[p@  
UD=[::##  
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/* 22'Ra[  
**TestMethod.java D-FT3Culw  
*/ xXlx}C  
package NetFox; `S+n,,l  
iJH?Z,Tjf  
g/frg(KF  
public class TestMethod { ~O~iP8T  
EW`3$J;  
} m"':f  
public TestMethod() .k$Yleg  
{ ///xx/weblogic60b2_win.exe
6l:uQz9  
try{ ~ mzX1[  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); B@v (ZY  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 85
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SiteFileFetch fileFetch = new SiteFileFetch(bean); _6!iv  
fileFetch.start(); lid0 YK-  
} *j(UAVp  
catch(Exception e){e.printStackTrace ();} nDcH;_<;9a  
:k-@w5(  
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} {#~A `crO  
-<L5;  
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public static void main(String[] args) &kcmkRRG  
{ R
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new TestMethod(); W[sQ_Z1C  
} z%BX^b$Hj  
} E@EP9X >  
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