http断点续传简单实现（java)

/* =K:[26  
**SiteFileFetch.java N[cIr{XBGN  
*/ {YiMd oMhg  
package NetFox; jj`#;Y  
import java.io.*; N}5  
import java.net.*; d}O\:\}y  
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public class SiteFileFetch extends Thread { {z>!Fw  
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SiteInfoBean siteInfoBean = null; //文件信息Bean bpc1>?  
long[] nStartPos; //开始位置 8oE`>Y  
long[] nEndPos; //结束位置 J!om"h  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 sV#%U%un  
long nFileLength; //文件长度 5$ik|e^:y  
boolean bFirst = true; //是否第一次取文件 u4hn9**a1  
boolean bStop = false; //停止标志 o%'1=d3R1Q  
File tmpFile; //文件下载的临时信息 YXp\C"~g  
DataOutputStream output; //输出到文件的输出流 vN(~}gOd\  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） uBts
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public SiteFileFetch(SiteInfoBean bean) throws IOException bkdXBCBx?  
{ 5ih>x3S1/  
siteInfoBean = bean; ~B[e*|d  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 6c!
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tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); #H7 SLQr\  
if(tmpFile.exists ()) JLm3qIC  
{
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bFirst = false; Pyuul4(  
read_nPos(); )<HvIr(xr  
} = 9Yfo,F  
else lZAGoR;0Ra  
{ v(;yy{>8"  
nStartPos = new long[bean.getNSplitter()]; ]?]M5rP  
nEndPos = new long[bean.getNSplitter()]; Z=8&`  
} ,<Cl^ ^a,  
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} 4AL,=C3  
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public void run() At@0G\^  
{ |"K%Tvxe  
//获得文件长度 Do(G;D`h+_  
//分割文件 ,~cK]!:>s  
//实例FileSplitterFetch 1)c{;x&W  
//启动FileSplitterFetch线程 \SmsS^z(]  
//等待子线程返回 WT\wV\Pu  
try{ mW]dhY 3X  
if(bFirst) X_'tgP9  
{ 6{;6~?U  
nFileLength = getFileSize(); GDCp@%xW  
if(nFileLength == -1) ;#zteqn  
{ %( OP  [  
System.err.println("File Length is not known!"); n=j)M  
} FV9{u[3m  
else if(nFileLength == -2) X[
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{ D 6'd&U{_  
System.err.println("File is not access!"); Vsi:O7|+ }  
} u)h {"pP  
else 1^^{;R7N  
{ jS]Saqd  
for(int i=0;i<nStartPos.length;i++) h<LS`$PK;E  
{ Zsapu1HoL\  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 97 SS0J  
} 5@l5exuG*m  
for(int i=0;i<nEndPos.length-1;i++) {$EX :ID  
{ s2L]H  
nEndPos = nStartPos[i+1]; 5 v.&|[\k  
} nY MtK  
nEndPos[nEndPos.length-1] = nFileLength; ]+`K\G ^X  
} TNh&g.  
} V^tD@N  
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//启动子线程 Z5'^Hj1,  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; a4uy}@9z  
for(int i=0;i<nStartPos.length;i++) :V6 [_VaF  
{ Up%XBA  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), _t,aPowX  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Ngx2N<$<*g  
nStartPos,nEndPos,i); qy?$t:*pp  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); q/:]+  
fileSplitterFetch.start(); rbOJ;CK  
} j8Mt"B  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), `~\SQ EY$  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); dlyGgaV*X  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", kT   
nEndPos = " + nFileLength); rZ,3:x-
:  
// fileSplitterFetch[nPos.length-1].start(); Uy=yA  
>7@,,~3  
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//等待子线程结束 #<Y3*^~5d  
//int count = 0; CSjd&G*ZB  
//是否结束while循环 3_G0eIE"u  
boolean breakWhile = false; Ma\%uEgTD  
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while(!bStop) h)s
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{ 'r=2f6G>cP  
write_nPos(); vg?(0Gasm*  
Utility.sleep(500); 6{d?3Jk  
breakWhile = true; f\?Rhyz  
:!Z|_y{b  
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for(int i=0;i<nStartPos.length;i++) ~c&sr5E  
{ prM)t8S

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if(!fileSplitterFetch.bDownOver) \aPH_sf,  
{ w8S pt  
breakWhile = false; ,y"vf^BE.  
break; +EA ")T<l  
} A]Hz?i  
} y)LX?d  
if(breakWhile) _GY2|x2c  
break; cb'Y
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//count++; ]~$@x=p2e  
//if(count>4) 1 39T*0C  
// siteStop(); k]gPMhe  
} p".wqg*W  
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System.err.println("文件下载结束！"); XU<owk  
} C&@'oLr  
catch(Exception e){e.printStackTrace ();} 1LFad>`  
} D',7T=C   
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//获得文件长度 *:\[;69[  
public long getFileSize() 8S#&XS>o  
{ nQ'NS  
int nFileLength = -1; sBWyUD  
try{ Qd~7OH4Lp  
URL url = new URL(siteInfoBean.getSSiteURL()); %qJg
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Qu/f>tJN;  
httpConnection.setRequestProperty("User-Agent","NetFox"); r9-ayp#pC  
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int responseCode=httpConnection.getResponseCode(); YG?4DF  
if(responseCode>=400) &B:L9^  
{ rpEIDhHv  
processErrorCode(responseCode); 2T%sHp~qt  
return -2; //-2 represent access is error [ZG>FJDl8  
} |0p@'X1  
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String sHeader; H{_D#It  
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for(int i=1;;i++) GGLSmfb)  
{ ,|8aDL?
 
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); irw5<l  
//Utility.log(in.readLine()); 3XUVUd~  
sHeader=httpConnection.getHeaderFieldKey(i); Xsn M}  
if(sHeader!=null) ]ZR` 6|"VO  
{ c#
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if(sHeader.equals("Content-Length")) *>2FcoN;  
{ {]|<|vc;GI  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); V]]!0ugvk(  
break; uZf 6W<a  
} O.Te"=^"F  
} 19% "F!^i  
else s 7%iuP  
break; P1L+Vnfu  
} D@5h$
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} w|I5x}ZFG  
catch(IOException e){e.printStackTrace ();} c#
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catch(Exception e){e.printStackTrace ();} 1H%p|'FKA  
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Utility.log(nFileLength); vEG7A$Z"  
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return nFileLength; @b2?BSdUp  
} 1Xh@x  
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//保存下载信息（文件指针位置） K}n.k
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private void write_nPos() ~[aV\r?  
{ U7fNA7#x"  
try{ O\oRM2^u}  
output = new DataOutputStream(new FileOutputStream(tmpFile)); dA2@PKK  
output.writeInt(nStartPos.length); [".94(qs  
for(int i=0;i<nStartPos.length;i++) 5Uhxl^c  
{ GaJE(N  
// output.writeLong(nPos); VqD_FS;E  
output.writeLong(fileSplitterFetch.nStartPos); ]4')H;'y  
output.writeLong(fileSplitterFetch.nEndPos); RV]QVA*i  
} $6ucz'  
output.close(); EHl~y=9  
}
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catch(IOException e){e.printStackTrace ();}  MkdC*|  
catch(Exception e){e.printStackTrace ();} \Lbwfd=  
} t\2-7Ohj6  
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//读取保存的下载信息（文件指针位置） 2cS94h  
private void read_nPos() TZn5s~t  
{ G&Yo2aADR  
try{ xVI"sBUu  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); DHhty qm  
int nCount = input.readInt(); ^?q
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nStartPos = new long[nCount]; .R4,fCN  
nEndPos = new long[nCount]; TR `C|TV>  
for(int i=0;i<nStartPos.length;i++) bF;|0X$ x  
{  { /8s`m  
nStartPos = input.readLong(); 'm<L}d  
nEndPos = input.readLong(); ]A+t@/k  
} EronNtu8i  
input.close(); QiqRx  
}  SN}3  
catch(IOException e){e.printStackTrace ();} Xrc{wDn  
catch(Exception e){e.printStackTrace ();} wT3D9N.  
} 1Qjc*+JzO.  
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private void processErrorCode(int nErrorCode) )Fqtb;W=  
{ _ Fk^lDI-  
System.err.println("Error Code : " + nErrorCode);  YOfYa  
} 6/'X$
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b;vVlIG  
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//停止文件下载 1?"Zrd  
public void siteStop() _S*QIb
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{ hr&UD|E=  
bStop = true; m<;MOS  
for(int i=0;i<nStartPos.length;i++) ^4[QX -_2  
fileSplitterFetch.splitterStop(); ~dgFr6  
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} U`{
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} !af;5F  
//负责部分文件的抓取 {)kL7>u]^V  
**FileSplitterFetch.java :a=]<_*x  
*/ Ir
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package NetFox; )5x$J01S  
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import java.io.*; XCez5Q1  
import java.net.*; Xz/aytp~A  
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public class FileSplitterFetch extends Thread { ,d HAD  
"HJQAy?W  
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String sURL; //File URL ^Y8G}Z|  
long nStartPos; //File Snippet Start Position ;ae6h [  
long nEndPos; //File Snippet End Position ^R+CkF4l l  
int nThreadID; //Thread's ID !_dW `  
boolean bDownOver = false; //Downing is over {=Py|N\\t  
boolean bStop = false; //Stop identical e)L!4Y44K  
FileAccessI fileAccessI = null; //File Access interface "`pg+t&  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ,yfJjV*I  
{ JmBMc}54  
this.sURL = sURL; xKT;1(Mk  
this.nStartPos = nStart; :X1Y  
this.nEndPos = nEnd; N>@.(f&w  
nThreadID = id; +\vN#xDz  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 cvpZF5mL]U  
} (5RZLRn  
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)1)&fN41i#  
public void run() f\:I1y  
{ Z#GR)
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while(nStartPos < nEndPos && !bStop) L'"od;(6R  
{ 1@+&6UC  
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try{ @3I?T Q1  
URL url = new URL(sURL); 9q
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); /sSif0I24  
httpConnection.setRequestProperty("User-Agent","NetFox"); C+C1(b;1  
String sProperty = "bytes="+nStartPos+"-"; e.|t12)L "  
httpConnection.setRequestProperty("RANGE",sProperty); E/d\ebX|  
Utility.log(sProperty); `K2vG`c  
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InputStream input = httpConnection.getInputStream(); D]V&
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//logResponseHead(httpConnection); #hEU)G'$+  
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byte[] b = new byte[1024]; hg `N`O  
int nRead; ,nw5 M.D_  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ]/mRMm9"3h  
{ 6x@]b>W  
nStartPos += fileAccessI.write(b,0,nRead); 368H6 Jj  
//if(nThreadID == 1) Bf,
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// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); gdqED}v  
} t.7_7`bin~  
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Utility.log("Thread " + nThreadID + " is over!"); y8|}bd<Sr  
bDownOver = true; iz`ys.Fu  
//nPos = fileAccessI.write (b,0,nRead); 
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} :O*62olC5  
catch(Exception e){e.printStackTrace ();} uD`Z\@Z  
} hnv0Loe.IW  
} H|cxy?iJ  
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mldY/;-H!1  
//打印回应的头信息 G;AV~1i:~  
public void logResponseHead(HttpURLConnection con) !j0iLYo(*  
{ *x.gPG  
for(int i=1;;i++) v;" pc)i  
{ c{/KkmI  
String header=con.getHeaderFieldKey(i); ;:Y/"5h  
if(header!=null) k%LsjN.S  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); NB&zBJ#  
Utility.log(header+" : "+con.getHeaderField(header)); CyJZip  
else :-b-)*TC;  
break; R9Y{kk0M  
} S`[r]msw  
} d 4
;   
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public void splitterStop() < 'r<MA<  
{ X*M--*0q'  
bStop = true; j1dz'G}hj  
} w8-L2)Q}I  
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} Ozc9yy!%  
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/* HK.Si]:  
**FileAccess.java 7+J<N@.d  
*//文件访问(定位，写) I]N!cEr;@-  
package NetFox; '\LU 8VC  
import java.io.*; pR~"p#Y  
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public class FileAccessI implements Serializable{ qo}u(pOj|  
5{M$m&$1  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 8
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RandomAccessFile oSavedFile; l8N5}!N  
long nPos; x>[ gShAV!  
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public FileAccessI() throws IOException 1);E!D[  
{ G)7J$4R  
this("",0); 2}#VB;B  
} `>{S?t<  
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public FileAccessI(String sName,long nPos) throws IOException -.7UpDg~  
{ <D(|}5qR  
oSavedFile = new RandomAccessFile(sName,"rw"); ~fly6j|u  
this.nPos = nPos; L(kW]  
oSavedFile.seek(nPos); cN#f$  
} 9B1bq#  
x/#.%Ga#T  
!Ka~X!+\  
public synchronized int write(byte[] b,int nStart,int nLen) eLop}*k  
{ .+CMm5T  
int n = -1; <+; cgF!+  
try{ VI^~I;M^  
oSavedFile.write(b,nStart,nLen); -<q@0IYyi  
n = nLen; $ 4A!Y  
} {Gr"oO`&"  
catch(IOException e) V?z
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{ ]4&B*
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e.printStackTrace (); A,GJ6qp3  
} yI*h"?7T  
qyYf&VC}  
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return n; (I(k$g[>  
} Y@V6/D} 1  
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} +Ram%"Zwh  
/Oa.@53tK6  
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/* %Z#[{yuFs  
**SiteInfoBean.java D$bJs O  
*/ <e'l"3+9(  
package NetFox; SrSm%Dv  
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public class SiteInfoBean { / , .rUn1  
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^VlPnx8y=  
private String sSiteURL; //Site's URL 'd|E>8fejG  
private String sFilePath; //Saved File's Path <=!|U0YV  
private String sFileName; //Saved File's Name ?nx 1{2[  
private int nSplitter; //Count of Splited Downloading File Q02:qn?T  
#+PfrS=  
82Nw6om6i  
public SiteInfoBean() .1?7)k v  
{//nSplitter的缺省值为5 <<9Y=%C+  
//default value of nSplitter is 5 3 p9LVa  
this("","","",5); oJ)v6"j  
} rZ7)sE5L  
3`Q>s;DjIU  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) kn7Qvk[+  
{ e!*%U=[Q  
sSiteURL= sURL; u:O6MO9^  
sFilePath = sPath; jj"?#`cW  
sFileName = sName; E 5bo60z  
this.nSplitter = nSpiltter; Z~Z+Yt;,9a  
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>dqeGM7Np>  
} Kkz2N  
;Ajy54}
7  
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public String getSSiteURL() e.^Y4(  
{ $;%dQ!7*  
return sSiteURL; QCk(qlN'h9  
} Z8_QKw>  
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IpMZ{kJlv`  
public void setSSiteURL(String value) _79 ?,U]  
{ ^5![tTJ  
sSiteURL = value; #o-CG PE  
} VNLggeX'U  
n`)wD~mk  
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public String getSFilePath() 2VNfnk  
{ 66~]7w  
return sFilePath; Dhe ]f#d  
} Lg
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Z ]WA-Q6n  
public void setSFilePath(String value) Sk,9<@  
{ 8q&*tpE  
sFilePath = value; 2Md'<.  
} IKV:J
9  
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public String getSFileName() (">gLr  
{ "ZyWU f  
return sFileName; ~h*p A8^L  
} xiPP&$mg  
`L=$,7`  
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public void setSFileName(String value) sZhl.[&zo  
{ l6Q75i)eF  
sFileName = value; #GHLF  
} :+>:>$ao  
Z"fnjH
 
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public int getNSplitter() 2<@27C5  
{ s GP}>w-JZ  
return nSplitter; 1y5$  
} h}_1cev?  
;Q =EI%_tv  
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public void setNSplitter(int nCount) jHx<}<  
{ :i6k6=  
nSplitter = nCount; -cHX3UAEI  
} ?geEq'  
} O$=)  
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H19C
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/* 97um7n  
**Utility.java 5PQs1B  
*/ [af<FQ{
  
package NetFox; emV@kN.  
#?z1cgCg  
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public class Utility { a,U =irBA  
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public Utility() -R;.Md_  
{ q#RVi8('  
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} o?J>mpC  
ZC1U  
//线程睡眠 z.[ Ok  
public static void sleep(int nSecond) m dC.M$  
{ ntSPHK|'  
try{ F=hfbCF5x  
Thread.sleep(nSecond); 8F<Qc*'  
} imtW[y+4  
catch(Exception e) oWpy^=D_  
{ ,diV;d  
e.printStackTrace (); BV&}(9z  
} LTY@}o]\U  
} >Tld:  
0=8.8LnN(  
//日志 F^=|NlU&%  
public static void log(String sMsg) ]*^mT&$7  
{ P$)9osr  
System.err.println(sMsg); |Js96>B:  
} [j5^Zb&0  
V&_5q`L  


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public static void log(int sMsg) 3Lq?Y7#KQp  
{ `\&qk)ZP  
System.err.println(sMsg); XQk9 U  
} &,fBg6A%  
} Z$,1Tk"O/s  
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"$#x+|PyC  
/* -{ZTp8P>  
**TestMethod.java AdB5D_ Ir  
*/ .l*]W!L]  
package NetFox; j~"X`:=  
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public class TestMethod { yi7-[W}  
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public TestMethod() u9>.x zYG  
{ ///xx/weblogic60b2_win.exe "wxs  
try{ q]5"V>D \  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); FI~)ZhE)]  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); QHsS|\u  
SiteFileFetch fileFetch = new SiteFileFetch(bean); jjz<V(Sk  
fileFetch.start(); "31GC7  
} ^$_a_ft#  
catch(Exception e){e.printStackTrace ();} 9\Mesf1$o  
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x
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} 0pu])[P]_[  
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public static void main(String[] args) $RK
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{ c?e
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new TestMethod(); \GbT^!dj  
} m{x!uq  
} >lyUr*4PX  
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