http断点续传简单实现（java)

/* |P[w==AAf  
**SiteFileFetch.java 1j
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*/ /rMI"khB  
package NetFox; t'?.8}?)I&  
import java.io.*; PjZvQ\Z  
import java.net.*; i;]"n;>+/  
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public class SiteFileFetch extends Thread { Qr1"Tk7s  
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SiteInfoBean siteInfoBean = null; //文件信息Bean (^s>m,h  
long[] nStartPos; //开始位置 O9vQp  
long[] nEndPos; //结束位置 ,X#2\r<|  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 9G9fDG#F\I  
long nFileLength; //文件长度 "k/;[ Wt]  
boolean bFirst = true; //是否第一次取文件 w0ht  
boolean bStop = false; //停止标志 BZ:H`M`n  
File tmpFile; //文件下载的临时信息 --PtZ]Z  
DataOutputStream output; //输出到文件的输出流 A$<.a
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） Lilr0|U+  
public SiteFileFetch(SiteInfoBean bean) throws IOException l%[EXZ  
{ M*!agh  
siteInfoBean = bean; lU
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//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); b8~Bazk  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); C3*gn}[  
if(tmpFile.exists ()) I2TaT(e\  
{ >[MX:Yh  
bFirst = false; `)` n(B  
read_nPos(); <%($7VMev  
} "|Xk2U  
else Gnf~u[T6  
{ }#.L7SIJ<J  
nStartPos = new long[bean.getNSplitter()]; y603$Cv  
nEndPos = new long[bean.getNSplitter()]; ^X0P'l&D2  
} m4aB*6<lq  
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} OTy.VT|  
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public void run() txW{7+,  
{ Q?e*4ba  
//获得文件长度 (0j}-iaQEZ  
//分割文件 j:5=s%S  
//实例FileSplitterFetch }3o|EXx=  
//启动FileSplitterFetch线程 W"zab
 
//等待子线程返回 xGu r  
try{ PfreAEv,  
if(bFirst) Nd`%5%'::  
{ !;0U,!WI  
nFileLength = getFileSize(); EKA#|^Q:NX  
if(nFileLength == -1) cVubb}ou  
{ pNOwDJtK  
System.err.println("File Length is not known!"); qC}-_u7s
 
} DBPRGQ  
else if(nFileLength == -2) _(Sa4Vb=Q6  
{ H
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System.err.println("File is not access!"); Z9MdD>uwi  
} %C$%!C  
else kgnmGuka  
{ &0='r;*i  
for(int i=0;i<nStartPos.length;i++) 3|WW
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{ *FC=X)_&W  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); P\w\N2  
} k40* e\  
for(int i=0;i<nEndPos.length-1;i++) L$9.8W  
{ s~>d:'k7|  
nEndPos = nStartPos[i+1]; \n{qsf:  
} {. 2k6_1[  
nEndPos[nEndPos.length-1] = nFileLength; :E_g"_  
} z*kutZ:6Y  
} 9^,Lc1"M>  
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x$IX5:E#e  
//启动子线程 bLe<G  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; &=#[(vl  
for(int i=0;i<nStartPos.length;i++) >_o}  
{ &QDW9 Mi  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), E_k$W5  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 'SCidN(n  
nStartPos,nEndPos,i); #bMuvaP~  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); |UK}  
fileSplitterFetch.start(); K<pV  
} 4kG,*3&2  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), S/^"@?z,vE  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); X}tVmO?  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", N$h{Yvbn  
nEndPos = " + nFileLength); &0NFb^8+  
// fileSplitterFetch[nPos.length-1].start(); 'XZ)!1N  
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//等待子线程结束 T?
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//int count = 0; ])L A42|  
//是否结束while循环  '`eO\huf  
boolean breakWhile = false; KMU4n-s"o  
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while(!bStop) ]3VI|f$$  
{ -M[$Zy^  
write_nPos(); G]fRk^~  
Utility.sleep(500); %F!1  
breakWhile = true; #>%X_o-o23  
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for(int i=0;i<nStartPos.length;i++) lz"OC<D}(  
{ BlXB7q,  
if(!fileSplitterFetch.bDownOver) }RmU%IYc  
{ pcYG~pZ9  
breakWhile = false; IkBei&4F`  
break; !'mq ?C=  
} _acE:H  
} 0Uz\H0T1  
if(breakWhile) UG2nX3?  
break; ROk5]b.  
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XLAN Np%E  
//count++; FP;Ccl"s  
//if(count>4) @r#v[I  
// siteStop(); .Jt[(;  
} ;\lW5ZX  
x
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System.err.println("文件下载结束！"); Z7_m)@%;kk  
} JS*m65e  
catch(Exception e){e.printStackTrace ();} um4yF*3b9  
} 4d8B`Fa9  
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enp)-nS0  
//获得文件长度 } w 5l  
public long getFileSize() ?RK]FP"A  
{ &e;=cAXG  
int nFileLength = -1; F{eU";D  
try{ G`\f  
URL url = new URL(siteInfoBean.getSSiteURL()); Xb{ [c+.  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ^j"
.  
httpConnection.setRequestProperty("User-Agent","NetFox"); QAvir%Y9Q  
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int responseCode=httpConnection.getResponseCode(); 7PANtCFb&  
if(responseCode>=400) 4g :>[q  
{ 5e$~)
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processErrorCode(responseCode); dHK`eS$sb  
return -2; //-2 represent access is error wvbPnf^y  
} e XfZ5(na  
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String sHeader; /%&2HDA)  
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for(int i=1;;i++) yto,>Utzg  
{ -C<zF`jO  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); xZ4~Oo@@_'  
//Utility.log(in.readLine()); qe!fk?T}  
sHeader=httpConnection.getHeaderFieldKey(i); H&]gOs3So  
if(sHeader!=null) yil[gPy4B  
{ w9,iq@  
if(sHeader.equals("Content-Length")) 2 !At2P2  
{ z)9wXo#~  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Xtp"QY p  
break; ;PjQt=4K  
} &2`Fn!m  
} sFQ^2PwbS  
else M-[$L XR  
break; Zf'TJ`S  
} o>7ts&rk  
} iK12pw  
catch(IOException e){e.printStackTrace ();} Q5FM8Q
 
catch(Exception e){e.printStackTrace ();} #m[|2R  
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Utility.log(nFileLength); =:/BV
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return nFileLength; /\H>y  
} LE*h9((  
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I_xXDr  
//保存下载信息（文件指针位置） tkXEHsRT  
private void write_nPos() ;$a@
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{ '1$!jmY  
try{ q*2N{  
output = new DataOutputStream(new FileOutputStream(tmpFile)); g_G6~-.9I  
output.writeInt(nStartPos.length); e_
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for(int i=0;i<nStartPos.length;i++) :PtF+{N>  
{ pp
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// output.writeLong(nPos); jcI&w#re  
output.writeLong(fileSplitterFetch.nStartPos); YhY
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output.writeLong(fileSplitterFetch.nEndPos); ds&e|VSH;  
} /r-aPJX  
output.close(); `&-
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} uPRQU+  
catch(IOException e){e.printStackTrace ();} Ay !G1;  
catch(Exception e){e.printStackTrace ();} *Mw_0Y  
} CT1ja.\;  
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(ZY@$''  
//读取保存的下载信息（文件指针位置） V^\8BVw  
private void read_nPos() j%y$_9a7  
{ 6$ Gep  
try{ }J7zTj~{  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); <
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int nCount = input.readInt(); rtL}W__  
nStartPos = new long[nCount]; .N*Pl(<[  
nEndPos = new long[nCount]; VMCLHpSfW  
for(int i=0;i<nStartPos.length;i++) ({NAMc*  
{ dlG=Vq&Y  
nStartPos = input.readLong(); jS]><rm  
nEndPos = input.readLong(); =IUUeFv +r  
} 6<$Odd
 
input.close(); "h|'}7p  
} 9Ffp2NW`;  
catch(IOException e){e.printStackTrace ();} ;q:jl~  
catch(Exception e){e.printStackTrace ();} ?gwUwOV"  
} jaa"~5TO8  
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private void processErrorCode(int nErrorCode) XXh6^@H=  
{ 6<'21  
System.err.println("Error Code : " + nErrorCode); 8P"_#M?!  
} P1NJ
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//停止文件下载 3;8!rNN  
public void siteStop() ZvUC
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{ #rY sj-2  
bStop = true; HU9Sl*/  
for(int i=0;i<nStartPos.length;i++) )x]3Zq  
fileSplitterFetch.splitterStop(); F*.g;So  
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} {O+Kw<d  
} JMVNmq&0  
//负责部分文件的抓取 TuW/N L|  
**FileSplitterFetch.java 1Jj Y!  
*/ CEC nq3  
package NetFox; YFTjPBV  
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import java.io.*; 9{$'S4  
import java.net.*; HFqm6|  
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public class FileSplitterFetch extends Thread { +z9gbcx  
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String sURL; //File URL j+^
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long nStartPos; //File Snippet Start Position N |1>ooU[  
long nEndPos; //File Snippet End Position OKHX)"j\\  
int nThreadID; //Thread's ID ^::E
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boolean bDownOver = false; //Downing is over P1zdK0TM  
boolean bStop = false; //Stop identical ?\#N9+{W  
FileAccessI fileAccessI = null; //File Access interface <BW[1h1k5_  
ncSFj.}w]  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ^{\<N()R  
{ (708H_  
this.sURL = sURL; c)Ic#<e(  
this.nStartPos = nStart; DaH?@Q
 
this.nEndPos = nEnd; gZEi]/8_  
nThreadID = id; Uh'#izm[l  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Lgz$]Jbl8  
} 2jbIW*  
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public void run() x)UwV  
{ !J=sk4T  
while(nStartPos < nEndPos && !bStop) )I\=BPo|B  
{ a,o_`s<  
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try{ j
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URL url = new URL(sURL); #eN{!Niy&U  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); )9S>ZZF  
httpConnection.setRequestProperty("User-Agent","NetFox"); }@+NN ?P  
String sProperty = "bytes="+nStartPos+"-"; q\rC5gk>  
httpConnection.setRequestProperty("RANGE",sProperty); Q`#4W3-,  
Utility.log(sProperty); 2Sq_Tw3^  
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InputStream input = httpConnection.getInputStream(); TM8=U-A  
//logResponseHead(httpConnection); ~w</!s  
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byte[] b = new byte[1024]; K
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int nRead; yIb,,!y9{  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) \]9.zlB  
{ !m(4F(!"h  
nStartPos += fileAccessI.write(b,0,nRead); ]hud4i~  
//if(nThreadID == 1) >|Q:g,I  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); NWfAxkz{/  
} ?k[p<U
o  
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Utility.log("Thread " + nThreadID + " is over!"); fZKt%m  
bDownOver = true; kGkA:g:  
//nPos = fileAccessI.write (b,0,nRead); Y:ldR  
} `imWc"'Ej  
catch(Exception e){e.printStackTrace ();} 0GDvwy D1  
} 3u>8\|8wz  
} h7X_S4p/Mg  
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N4K8 u'f^  
//打印回应的头信息 ^+SkCO  
public void logResponseHead(HttpURLConnection con) PS S?|Vk  
{ 'O6]0l  
for(int i=1;;i++) Gq#~vr  
{ ,uz ]V1  
String header=con.getHeaderFieldKey(i); B$?qQ|0:=  
if(header!=null) XI Jlc~2  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); /Jf~25
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Utility.log(header+" : "+con.getHeaderField(header)); %~NH0oFO  
else ZAuWx@}  
break; qpJ{2Q  
} t!1$$e?`r  
} 7*wVI+  
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"Dy'Kd%,%/  
public void splitterStop() Z.i{i^/#(  
{ %b?$@H-Re  
bStop = true; o$.e^XL  
} x\s,= n3z  
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} 7:NmCpgL!  
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/* ":Edu,6O  
**FileAccess.java Lh$dzHq  
*//文件访问(定位，写) ExHAY|UA  
package NetFox; X
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import java.io.*; "k$JP  
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public class FileAccessI implements Serializable{ DZ ^1s~  
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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 HjWq[[Nz  
RandomAccessFile oSavedFile; =wi*Nd7L  
long nPos; '[P}&<ie,  
P ,eH5w"  
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public FileAccessI() throws IOException L3(^{W]|  
{ 1+y"i<3)  
this("",0); 02JL*  
} vOI[Z0Lq9h  
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*
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public FileAccessI(String sName,long nPos) throws IOException
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{ Fr
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oSavedFile = new RandomAccessFile(sName,"rw"); 0m9ZQ O  
this.nPos = nPos; ^a9 oKI9n  
oSavedFile.seek(nPos); ^ons:$0h  
} w8~K/>!f  
j%Y\A~DV  
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public synchronized int write(byte[] b,int nStart,int nLen) Ek.&Sf$cd'  
{ B`#h{)[  
int n = -1; $<)Yyi>6E  
try{ &[|VZ[  
oSavedFile.write(b,nStart,nLen); mjnUs-`W|  
n = nLen; HO|-@yOF^  
} xcCl (M]+  
catch(IOException e) I12KT~z<r  
{ {#Q\z>  
e.printStackTrace (); farDaS[\VY  
} ://U^sFL  
+zOOdSFk.  
{
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return n; U Lmg$T&  
} &;q<M_<  
eQ
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} @y~P&HUN  
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/* &w~Xa( uu  
**SiteInfoBean.java 73NZ:h%=  
*/ FY;+PY@I{  
package NetFox; >X Qv?5  
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public class SiteInfoBean { ?H;{~n?  
cHvF*A  
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private String sSiteURL; //Site's URL ( 76{2  
private String sFilePath; //Saved File's Path o#i ]"  
private String sFileName; //Saved File's Name nf%4sIQ*x  
private int nSplitter; //Count of Splited Downloading File 7$T8&Mh  
&&RA4  

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public SiteInfoBean() ij)Cm]4(2  
{//nSplitter的缺省值为5 r)l`  
//default value of nSplitter is 5 nTnRGf\T  
this("","","",5); )BV=|,j  
} 9fVj 8G  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) whkJpK(  
{ pVokgUrC  
sSiteURL= sURL; Wpm9`K  
sFilePath = sPath; H*!5e0~rR  
sFileName = sName; N7.  @FK  
this.nSplitter = nSpiltter; ;lfWuU%R  
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v  
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} EnCU4CU`  
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public String getSSiteURL() $iJnxqn  
{ V,4.$<e  
return sSiteURL; N=ifIVc  
} j=3-Qk`"/|  
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public void setSSiteURL(String value) u(vw|nj`  
{ E[S':Q  
sSiteURL = value; @W9H9PWv&  
} =:5<{J OG  
a&5g!;.  
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public String getSFilePath() Xem| o&  
{ ofwQ:0@  
return sFilePath; qC j*>D  
} *wUdC  
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public void setSFilePath(String value) gX/NtO%  
{ {[3YJkrM  
sFilePath = value; Dc:DY:L^  
} 5EhE`k4  
BMjfqX  
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public String getSFileName() >(tO QeN  
{ o>u!CL<  
return sFileName; IA4+ad'\E  
} 9v?V  
X%J%A-k]  
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public void setSFileName(String value) YC)hX'A\  
{ a!u3HS-i  
sFileName = value; R~c1)[[E  
} ,8`O7V{W  
#:W%,$9\P  
|Y{
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public int getNSplitter() B!`\L!  
{ 3/tJDb5  
return nSplitter; q!2<=:f  
} ;Uk!jQh  
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public void setNSplitter(int nCount) $h]NXC6J  
{ RUc\u93n  
nSplitter = nCount; *R!]47Y d  
} $'u\B  
} Iv1c4"  
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/* r /yHmEk&  
**Utility.java >nNl^ yqW  
*/ T{;=#rG<  
package NetFox; =+(Q.LmhC  
l'2H4W_+  
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public class Utility { x~(y "^ph  
jNqVdP]d\  
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public Utility() dqwWfn1lt  
{ iE+6UK  
a^/K?lAB8  
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} m9b(3  
o_3*;}k8  
//线程睡眠 s?+fPOF  
public static void sleep(int nSecond) f@*>P_t  
{ u7~mnl  
try{ cP('@K=p  
Thread.sleep(nSecond); M%;"c?g  
} TRCI\  
catch(Exception e) HYFN?~G  
{ g`.{K"N>!  
e.printStackTrace (); $$~a=q,P[  
} 1!s!wQgS  
} &$Ci}{{n
#  
-PXoMZx%  
//日志 7A[Ogro  
public static void log(String sMsg) $%;jk  
{ Wa{%0inZ  
System.err.println(sMsg); hJ4S3b  
} r?]
%d!   
8iOO1I?+  
VB's  
public static void log(int sMsg) y\z*p&I  
{ ( w5f(4  
System.err.println(sMsg); t@r#b67WJe  
} ;6zPiaDQ  
} ?AT(S  
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$BaK'7=3*  
/* g X8**g'  
**TestMethod.java m/KjJ"s,
 
*/ ,=x RoXYB}  
package NetFox; fxOE]d8v  
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public class TestMethod { |thad!?  
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67fIIXk&  
public TestMethod() 2
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{ ///xx/weblogic60b2_win.exe -2z,cj&E{  
try{ "C& Jwm?  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); .2/,XwIr  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); M-vC>u3Y  
SiteFileFetch fileFetch = new SiteFileFetch(bean); bbO+%-(X  
fileFetch.start(); dUZ$wbV%h  
} iW":DOdi_  
catch(Exception e){e.printStackTrace ();} ,Z?m`cx  
#[Z<=i~C  
(A2U~j?Ry}  
} -#daBx ?  
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hk/+  
public static void main(String[] args) %5`r-F  
{ +fkP+RVY  
new TestMethod(); T4vogoy  
} cu:-MpE  
} 1"M"h_4  
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