http断点续传简单实现（java)

/* jL}v9$  
**SiteFileFetch.java 8z\xrY  
*/ ]Hv[IodJ  
package NetFox; GQ ;;bcj&  
import java.io.*; B9S@(/"7  
import java.net.*; lyhiFkO iH  
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public class SiteFileFetch extends Thread { BZ^}J!Q'*  
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SiteInfoBean siteInfoBean = null; //文件信息Bean lp8v0e
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long[] nStartPos; //开始位置 dj%!I:Q>u  
long[] nEndPos; //结束位置 <1!O1ab  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 #g!.T g'  
long nFileLength; //文件长度 X@F
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boolean bFirst = true; //是否第一次取文件 8 Fbo3  
boolean bStop = false; //停止标志 hi[pVk~B)  
File tmpFile; //文件下载的临时信息 5!9zI+S|=`  
DataOutputStream output; //输出到文件的输出流 Flb&B1  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） \'j|BJ~L f  
public SiteFileFetch(SiteInfoBean bean) throws IOException %&bY]w  
{ ,hmL/K0"(5  
siteInfoBean = bean; *X}`PF   
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); sDV Q#}a  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Cgc\ ah  
if(tmpFile.exists ()) =2x^nW  
{ w4Z'K&d=  
bFirst = false; f
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read_nPos(); poFg1  
} ybUaTD@?}b  
else 4B][S'f  
{ P!k{u^$L  
nStartPos = new long[bean.getNSplitter()]; #X"@<l4F  
nEndPos = new long[bean.getNSplitter()]; kG*~|ma  
} Oow2>F%
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} <a+Z;>  
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public void run()
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{ tLmTjX .6  
//获得文件长度 e>7i_4(C  
//分割文件 4KrL{Z+}  
//实例FileSplitterFetch u#SWj,X  
//启动FileSplitterFetch线程 3+bt~J0  
//等待子线程返回 Aiea\jBv  
try{ Wm5dk9&x  
if(bFirst) rVsJ`+L  
{ Af{"pzY  
nFileLength = getFileSize(); Rx}Gz$
 
if(nFileLength == -1) A5w6]:f2  
{ p
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System.err.println("File Length is not known!"); bN@ l?w  
} NaCy@  
else if(nFileLength == -2) u<&m]]*  
{ H>@+om  
System.err.println("File is not access!"); .%QXzIa3F  
} CJI~_3+K  
else W@!S%Y9  
{ ;9g2?-svw  
for(int i=0;i<nStartPos.length;i++) OZ!^ak  
{ L8 @1THY  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 3f;>" P}  
} " 2Dngw  
for(int i=0;i<nEndPos.length-1;i++) FxtI"g\0  
{
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nEndPos = nStartPos[i+1]; VLN_w$iEq  
} e?f IXk~b  
nEndPos[nEndPos.length-1] = nFileLength; #R RRu2  
} 7=, ;h  
} wec)Ctj+  
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//启动子线程 s"?3]P  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; sn>~O4"  
for(int i=0;i<nStartPos.length;i++) }:#P)8/v>%  
{ WMP,\=6k0  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ,6W>can  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), S 6,.FYH  
nStartPos,nEndPos,i); B?o7e<l[  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Xb,3Dvf  
fileSplitterFetch.start(); BFW&2  
} GvlS%  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), OK gqT!  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); A.w:h;7  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", vVcob}ZH  
nEndPos = " + nFileLength); ei5~&  
// fileSplitterFetch[nPos.length-1].start(); 4nz35BLr  

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2)  
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//等待子线程结束 dnuu&Rv  
//int count = 0; ua `
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//是否结束while循环 *4_Bd=5(U  
boolean breakWhile = false; s(roJbJ_;  
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while(!bStop) gKCX|cULY  
{ FNId;  
write_nPos(); ]jRfH(i  
Utility.sleep(500); o,3a4nH;  
breakWhile = true; 8sK9G` k  
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for(int i=0;i<nStartPos.length;i++) bK-
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{ maR"t+  
if(!fileSplitterFetch.bDownOver) cPc</[x[W  
{ ]]j;
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breakWhile = false; {2"zVt#h  
break; dcWD(-  
} jm r"D>  
} ##4HYQ%E  
if(breakWhile) Mh 7DV  
break; )sQ*Rd@t[8  
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//count++; m<2M4u   
//if(count>4) BJo*'US-Q  
// siteStop(); mU9kVx1+  
} ^L&iR0  
, SnSW-P  
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System.err.println("文件下载结束！"); 63x?MY6  
} '>C5-R:O  
catch(Exception e){e.printStackTrace ();} i
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} Ok\7y-w^  
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//获得文件长度 %C_HXr@  
public long getFileSize() ',5ky{  
{ =zs`#-^8  
int nFileLength = -1; t9IW/Q  
try{ 57'4ljvYi  
URL url = new URL(siteInfoBean.getSSiteURL()); 2jCfT>`3  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection ();
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httpConnection.setRequestProperty("User-Agent","NetFox"); yyy|Pw4:Z  
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int responseCode=httpConnection.getResponseCode(); QUQ'3  
if(responseCode>=400) `,*5wBC  
{ 1D!<'`)AY  
processErrorCode(responseCode); #@nezu2  
return -2; //-2 represent access is error LC!bIm5'  
} LvYB7<zk>  
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String sHeader; J`1rJ  
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for(int i=1;;i++) WQO) =n  
{ G9<X_  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); /fV;^=:8c  
//Utility.log(in.readLine()); q?/a
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sHeader=httpConnection.getHeaderFieldKey(i); "|KP'<8%  
if(sHeader!=null) w_u\sSQ`!  
{ OJy#w{4  
if(sHeader.equals("Content-Length")) 3>VL}Ui}  
{ CF5`-wj/#  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 0>Z_*U~6  
break; *%@h(js  
} (Px OE  
} Vj>8a)"B5a  
else \v)+.m?n  
break; gCY';\f!  
} "kgdbAZ  
} [QT#Yf0  
catch(IOException e){e.printStackTrace ();} i@M[>~  
catch(Exception e){e.printStackTrace ();} Y,zxbXZv'5  
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Utility.log(nFileLength); B~Xw[q  
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return nFileLength; XAL1|]S  
} y7Df_|Z  
#|PS&}6wU  
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//保存下载信息（文件指针位置） ~Vjl7G\7i  
private void write_nPos() q.`NtsW!\+  
{ 5(HG|  
try{ x{
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output = new DataOutputStream(new FileOutputStream(tmpFile)); `$aZ0+  
output.writeInt(nStartPos.length); Wbq
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for(int i=0;i<nStartPos.length;i++) _~iw[*#u  
{ SQt4v"  
// output.writeLong(nPos);
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output.writeLong(fileSplitterFetch.nStartPos); Aj+F |l  
output.writeLong(fileSplitterFetch.nEndPos); pr UM-u8  
}  t[ C/  
output.close(); xAMW-eF?d  
} r<Kx0`y  
catch(IOException e){e.printStackTrace ();} 3HY9\'t6  
catch(Exception e){e.printStackTrace ();} ZSd4z:/  
} PdtvU-(  
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//读取保存的下载信息（文件指针位置） JbQ) sp  
private void read_nPos() 63
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{ =^50FI|  
try{ <1\Nb
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DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); *N'p~LJ  
int nCount = input.readInt(); tS8u  
nStartPos = new long[nCount]; ?o#%Xs  
nEndPos = new long[nCount]; o"R7,N0rB  
for(int i=0;i<nStartPos.length;i++) LW_f  
{ ?R.j^S^  
nStartPos = input.readLong(); @A^;jk  
nEndPos = input.readLong(); k-OPU,  
} =xx]@  
input.close(); 'qX|jtdM  
} G<rHkt@[  
catch(IOException e){e.printStackTrace ();} #d2.\X}A"3  
catch(Exception e){e.printStackTrace ();} z]D69O b  
} *w0%d1  
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private void processErrorCode(int nErrorCode) SPmq4  
{ a8Nh
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System.err.println("Error Code : " + nErrorCode); mmRJ9OhS  
} =k`Cr0aPF  
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//停止文件下载 i|*)I:SHU  
public void siteStop() 'o>B'$  
{ -"60d @.  
bStop = true; =CVBBuVy  
for(int i=0;i<nStartPos.length;i++) }"!I[Ek> y  
fileSplitterFetch.splitterStop(); q\p:X"j|  
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} vJOw]cwq  
} XtSkh] #z!  
//负责部分文件的抓取 t+T4-1 3a  
**FileSplitterFetch.java !6>~?gNd  
*/ o@i#|kx,  
package NetFox; 6 EC*  
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import java.io.*; C-6F]2:  
import java.net.*; lHe{\N[C  
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public class FileSplitterFetch extends Thread { c?&X?<  
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String sURL; //File URL 7f!YoW;1  
long nStartPos; //File Snippet Start Position ^mO~W!"  
long nEndPos; //File Snippet End Position |My4SoOF  
int nThreadID; //Thread's ID \k!{uRy'  
boolean bDownOver = false; //Downing is over 8=uu8-l8g  
boolean bStop = false; //Stop identical x$Oq0d{
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FileAccessI fileAccessI = null; //File Access interface kH7(@Pa  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException OGg>#vj,s  
{ Y^}Z>  
this.sURL = sURL; 3L}!RB  
this.nStartPos = nStart; p &"`RS#Z  
this.nEndPos = nEnd; W~9tKT4  
nThreadID = id; qjdMqoOCjl  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 (
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} eMY<uqdw  
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public void run() v)t:|Q{I  
{ Zxs|%bQ  
while(nStartPos < nEndPos && !bStop) !()
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{ ^^as'Dk  
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try{ 6vNrBB  
URL url = new URL(sURL); %Iv,@}kvT+  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); KZ ;k)O.Ov  
httpConnection.setRequestProperty("User-Agent","NetFox"); ,J^b0@S  
String sProperty = "bytes="+nStartPos+"-"; +&( Mgbna  
httpConnection.setRequestProperty("RANGE",sProperty); qr4pR-Gdr  
Utility.log(sProperty); ^!ZC?h!rG  
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InputStream input = httpConnection.getInputStream(); q?DTMKx  
//logResponseHead(httpConnection); :xv!N*Le  
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byte[] b = new byte[1024]; ]X5 9  
int nRead; Vjp1RWb  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) *4+"Lh.KS  
{ C=)A6 ;=se  
nStartPos += fileAccessI.write(b,0,nRead); P.;aMRMR  
//if(nThreadID == 1) u:gN?O/G  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 9- YwkK#z  
} ^O<&fD  
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Utility.log("Thread " + nThreadID + " is over!"); TKY*`?ct  
bDownOver = true; ,t9^j3Ixg  
//nPos = fileAccessI.write (b,0,nRead); y4I6  
} NS%xTLow-  
catch(Exception e){e.printStackTrace ();} IE&!YP(U(  
} t2I5hSf  
} v99B7VH4  
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//打印回应的头信息 dzsmIV+  
public void logResponseHead(HttpURLConnection con) gL[yA?GoM  
{ =2zJ3&9  
for(int i=1;;i++) hp*/#
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{ E.ly#2?  
String header=con.getHeaderFieldKey(i); ceM6{N<_U  
if(header!=null) |_*O'#jx  
//responseHeaders.put(header,httpConnection.getHeaderField(header));  TYmP)  
Utility.log(header+" : "+con.getHeaderField(header)); =/Mq5.  
else -pa )K"z  
break; ?_$=l1vf  
} PMh^(j[  
} m-*i>4;  
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public void splitterStop() 0Lc9M-Lg  
{ Lz!,kwg  
bStop = true; !?
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} 6c"0})p  
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} RIXMJ7e7  
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/* TRQF^P3o  
**FileAccess.java 0]=i}wL 8  
*//文件访问(定位，写)  ,^;)<[  
package NetFox; =aA+~/~8%  
import java.io.*; =aj/,Q]  

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public class FileAccessI implements Serializable{ an
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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 /X(t1+  
RandomAccessFile oSavedFile; 8X`tU<A
b  
long nPos; pr#z=vqH  
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public FileAccessI() throws IOException ? glSC$b  
{ IOoz^/'  
this("",0); j!4et;  
} =fve/_Q~  
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public FileAccessI(String sName,long nPos) throws IOException ?~;:jz|9<'  
{ ]dk8lZ;bo  
oSavedFile = new RandomAccessFile(sName,"rw"); YZ7|K<   
this.nPos = nPos; 8` @G;o  
oSavedFile.seek(nPos); zG9Y!
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} !n$tr  
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public synchronized int write(byte[] b,int nStart,int nLen) I1\a[Xe8E  
{ Z@&Dki  
int n = -1; Ucm :S-  
try{ C;`XlQG `  
oSavedFile.write(b,nStart,nLen); 6290ZNvr  
n = nLen; 7#U^Dx\yh  
} mG`e3X6@-  
catch(IOException e) T[4<R 5}  
{ )h|gwERj  
e.printStackTrace (); eDJfU  
} ~aOuG5XK  
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return n; {h2TD P  
} pT1[<X!<s  
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} &jczO-R^  
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/* w'fT=v
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**SiteInfoBean.java DUe&r,(4O  
*/ ~L_hZso4  
package NetFox; ;3@YZM'wt  
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public class SiteInfoBean { @qjfZH@  
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private String sSiteURL; //Site's URL s^|.Zr;,>  
private String sFilePath; //Saved File's Path 3g~^[&
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private String sFileName; //Saved File's Name T<@cd|`  
private int nSplitter; //Count of Splited Downloading File TsUOpEuX  
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public SiteInfoBean() k`9)=&zX+  
{//nSplitter的缺省值为5 `S.ZS}~!F  
//default value of nSplitter is 5 )0e2ic/  
this("","","",5); d]i(h~?_  
} RQp|T5Er*  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) !!V#v9{  
{ +:-57  
sSiteURL= sURL; ^1x*lLf  
sFilePath = sPath; npyAJp  
sFileName = sName; nG,U>)  
this.nSplitter = nSpiltter; ls`,EFF  
+|{RE.DL  
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} $GQ-(/  
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public String getSSiteURL() )VK }m9Ae  
{ Za7q$7F7Bc  
return sSiteURL; P^Q[-e{  
} maY4g&'f  
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public void setSSiteURL(String value) (?kl$~&|  
{ l|+BC  
sSiteURL = value; ?D)<,  
} TLf9>= OVh  
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public String getSFilePath() pdb1GDl0q  
{ CGP3qHrXt  
return sFilePath; %?hsoj&k  
} m8JR@!t7  
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public void setSFilePath(String value) nL}5cPI  
{ <0.$'M~E  
sFilePath = value; KZe)K_1[  
} tYqs~B3  
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public String getSFileName() .E~(h*NW  
{ d~_`M
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return sFileName; u@P[Vb   
} >Aq870n  
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public void setSFileName(String value) GOB(#vu  
{ 4Kv[
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sFileName = value; F;!2(sPS  
} Koln9'tB  
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public int getNSplitter() ,kp\(X[J  
{ @l(vYJ:f  
return nSplitter; T\# *S0^  
} G>Em!4h  
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public void setNSplitter(int nCount) o:dR5v  
{ i=32KI(%  
nSplitter = nCount; V'2EPYB  
} ^Ori| 4}'  
} l n}}5Q  
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/* Uo_tUp_Q  
**Utility.java ]Lqt(c  
*/ p'?w2YN/  
package NetFox; xaKst p  
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public class Utility { DV]7.Bm  
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public Utility() N(3R|Ii  
{ r\9TMg`C  
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} /WnE:3G  
]y)Q!J )Q  
//线程睡眠 baoD(0d  
public static void sleep(int nSecond) ]`w}+B'/  
{ dd7 =)XT+  
try{ 2#/p|$;Ec'  
Thread.sleep(nSecond); 2$zU&p7sV  
} Q\J,}1<`6  
catch(Exception e) }yEoEI`  
{ 9<]a!:!^  
e.printStackTrace (); :Px\qh}K  
} oeL5}U6>g  
} 4`2$_T$F  
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//日志 e}cnX`B  
public static void log(String sMsg) mf|pNiQ,  
{ -05U%l1e  
System.err.println(sMsg); TL)O-  
} ?Zyok]s  
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public static void log(int sMsg) eE/%6g  
{ {rkn q_;0  
System.err.println(sMsg); azb=(l-  
} oBlzHBn>0  
} 8!h'j  
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/* "g
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**TestMethod.java <3 j~=-  
*/ hK}bj  
package NetFox; }Pg' vJW  
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public class TestMethod { Ha ZFxh-(  
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public TestMethod() D?+ RJs
  
{ ///xx/weblogic60b2_win.exe >4![&&  
try{ >3 Ko.3&  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); e.6Dl_  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); `h;}3r#R{  
SiteFileFetch fileFetch = new SiteFileFetch(bean); n2;9geq+  
fileFetch.start(); fEu9Jk  
} +>3]%i-\  
catch(Exception e){e.printStackTrace ();} It 2UfW  
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} a0zG(7.D  
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public static void main(String[] args) +6%7CC6  
{ l6B.6 '4)w  
new TestMethod(); T~Yg5J  
} Cals?u#U=  
} B {i&
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