http断点续传简单实现（java)

/* zP:cE  
**SiteFileFetch.java '=E3[0W  
*/ { F'Kk\f%:  
package NetFox; ?\U!huu  
import java.io.*; Wxkx,q?  
import java.net.*; Nrah;i+H\o  
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public class SiteFileFetch extends Thread { 9D 0dg(  
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SiteInfoBean siteInfoBean = null; //文件信息Bean uK("<u|  
long[] nStartPos; //开始位置 Aj9Ji"18za  
long[] nEndPos; //结束位置 ?f*Q>3
S)  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ewuXpv%vwW  
long nFileLength; //文件长度 ="%W2  
boolean bFirst = true; //是否第一次取文件 `gpQW~*R-;  
boolean bStop = false; //停止标志 ExSO|g]%
 
File tmpFile; //文件下载的临时信息 ZUp\Ep}  
DataOutputStream output; //输出到文件的输出流 Y4F6qyP)"  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） z305{B:Y  
public SiteFileFetch(SiteInfoBean bean) throws IOException ;' nL:\  
{ :s-o0$PlJ  
siteInfoBean = bean; EQIUSh)M  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); `p0ypi3hn  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 2$ !D* <  
if(tmpFile.exists ()) wNNB;n`l  
{ K9[e>  
bFirst = false; 1z*kc)=JF8  
read_nPos(); b?Pj< tA  
} "BKeot[""p  
else Z,c,G2D  
{ Eq^uK
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nStartPos = new long[bean.getNSplitter()]; v8/6wy?  
nEndPos = new long[bean.getNSplitter()]; TwvAj#j  
} LF?P> 1%-  
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} ?/M_~e.P  
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public void run() mxFn7.|r~  
{ =q(GHg;'  
//获得文件长度 'R9g7,53R  
//分割文件 maSgRf[g  
//实例FileSplitterFetch J^m<*  
//启动FileSplitterFetch线程 sT1&e5`W  
//等待子线程返回 ~vgA7E/XV  
try{ aF8k/$u  
if(bFirst) /}5B&TZ=(3  
{ _2hXa!yO  
nFileLength = getFileSize(); k$Rnj`*^  
if(nFileLength == -1) wU`!B<,j  
{ yg;_.4TpIO  
System.err.println("File Length is not known!"); k_GP>b\"k  
} YCy22@C  
else if(nFileLength == -2) 8I+d)(:  
{ g):]'  
System.err.println("File is not access!"); ?Qqd "=k4  
} va|rO#.=  
else 'GJVWpvUU  
{ MR'o{?{e`  
for(int i=0;i<nStartPos.length;i++) ~2
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{ U5/qf8)yO  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); uXQ >WI@eF  
} ?4z8)E9Ju  
for(int i=0;i<nEndPos.length-1;i++) ohc1 ~?3b  
{ F6S~$
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nEndPos = nStartPos[i+1]; 4B-yTyO  
}  0=6/yc  
nEndPos[nEndPos.length-1] = nFileLength; nhdTTap&9  
} jN/C'\QL  
} Nm]% }  
(A/0@f1#  
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//启动子线程 v })Q  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; |G=[5e^s[  
for(int i=0;i<nStartPos.length;i++) GlR~%q-jiQ  
{ Y/U{Qc\6  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ivrXwZ7jT  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), h ?#@~  
nStartPos,nEndPos,i); jB@4b'y  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); !rTmR@e$/  
fileSplitterFetch.start(); (:\LWJX0=  
} (paf2F
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// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), S7n"3.k  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); yu&Kh4AP  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 8SnS~._9  
nEndPos = " + nFileLength);  oYX{R  
// fileSplitterFetch[nPos.length-1].start(); *j*Du+  
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+nZRi3yu=  
//等待子线程结束 BIWD/|LQ  
//int count = 0; qeaA&(|5  
//是否结束while循环 QV)}3pW  
boolean breakWhile = false;
T{ nQjYb?  
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e 2*F;.)  
while(!bStop) ZKsQ2"8{M  
{ DB Xm  
write_nPos(); a#R%8)  
Utility.sleep(500); m3%
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breakWhile = true; n`#+L~X  
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for(int i=0;i<nStartPos.length;i++) T+BIy|O  
{ ^^Bm$9  
if(!fileSplitterFetch.bDownOver) NV(fN-L  
{ 3#<'[TF00t  
breakWhile = false; b#}t:yy  
break; G*Ib^;$u  
} 0
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} ;:^ Lv  
if(breakWhile) ox JGJ  
break; t_Z _!Qy  
z-)*Q  
|3"NwM>  
//count++; WxDb3l~  
//if(count>4) <q1'Li)_R  
// siteStop(); &V FjHW  
} I<9n(rA  
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System.err.println("文件下载结束！"); E.U0q
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} Flne=ij6g  
catch(Exception e){e.printStackTrace ();} p( HyRCH  
} 3P3:F2S R  
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//获得文件长度 Y)5)s0}  
public long getFileSize() U"/yB8!W  
{ QQSH +  
int nFileLength = -1; D@}St:m}  
try{ KWtu,~O_u  
URL url = new URL(siteInfoBean.getSSiteURL()); T&mbXMN  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); IMw
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httpConnection.setRequestProperty("User-Agent","NetFox"); CF,8f$:2  
#%:`p9p.S  
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int responseCode=httpConnection.getResponseCode(); .wM:YX'[G  
if(responseCode>=400) !k%l+I3J[  
{ 4LJ]l:m  
processErrorCode(responseCode); zuUQ."#i  
return -2; //-2 represent access is error b-,]A2.  
} ;K>{_kf  
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String sHeader; rL.<Z@-  
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for(int i=1;;i++) Zm`'MsgFr  
{ C,9)V5!tP2  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); D9e+  
//Utility.log(in.readLine()); :h^O{"au^  
sHeader=httpConnection.getHeaderFieldKey(i); [vZfH!vLP  
if(sHeader!=null) YG-Z.{d5Z  
{ T$#FAEz  
if(sHeader.equals("Content-Length")) iLjuE)6-$  
{ d3\OHkM0^  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); t5I^
1u6  
break; ',L{CQA?c  
} s$
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} k, $I59  
else 97['VOh0  
break; 6#OL ;Y]_  
} bnAT,v{  
} YJ&lB&xH  
catch(IOException e){e.printStackTrace ();} <GbnPG?  
catch(Exception e){e.printStackTrace ();} W?SP .-I  
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Utility.log(nFileLength); i5ajM,i/K  
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return nFileLength; ~ >&I^4  
} #Nu%]  
:;" aUHU'  
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//保存下载信息（文件指针位置） 6ctHL<^  
private void write_nPos() J-@o@!o  
{ ?/o2#iJx  
try{ {m?K2]](  
output = new DataOutputStream(new FileOutputStream(tmpFile)); U:s}/to  
output.writeInt(nStartPos.length); 5KL9$J9k  
for(int i=0;i<nStartPos.length;i++) c
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{ 3bT6W,J4T  
// output.writeLong(nPos); [0mFy)6  
output.writeLong(fileSplitterFetch.nStartPos); @Fm{6^  
output.writeLong(fileSplitterFetch.nEndPos); NqQM!B]  
} ^8o_Iz)r,  
output.close(); B2ek&<I7N  
} 0A) Vtj$  
catch(IOException e){e.printStackTrace ();} Yio>ft&g]  
catch(Exception e){e.printStackTrace ();} xI/{)I1f  
} v>x {jZkFL  
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//读取保存的下载信息（文件指针位置） W\ 1bE(AwZ  
private void read_nPos() o<C]+Nt,@  
{ 3i@ "D  
try{ PfwI@%2  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Fg
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int nCount = input.readInt(); &=+cov(3  
nStartPos = new long[nCount]; ]Ssw32yn  
nEndPos = new long[nCount]; +cPE4(d  
for(int i=0;i<nStartPos.length;i++) ,7n;|1`  
{ >z fq*_  
nStartPos = input.readLong(); 4y
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nEndPos = input.readLong(); @%I_&!d  
} 0?J|C6XM#4  
input.close(); E<X{72fb>  
} 0)6i~MglY  
catch(IOException e){e.printStackTrace ();} IGh !d?D  
catch(Exception e){e.printStackTrace ();} Z@>=&  
} 7G<KrKal  
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private void processErrorCode(int nErrorCode) 5
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{
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System.err.println("Error Code : " + nErrorCode); !I~C\$^U  
} 0Y38T)k  
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//停止文件下载 c&| '3i+  
public void siteStop() hJC p0F9O  
{ L&!g33J&  
bStop = true; q 2_N90u  
for(int i=0;i<nStartPos.length;i++) &viwo}ls0  
fileSplitterFetch.splitterStop(); QoT3;<r}  
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} Tdk2436=  
} bo~{<UT  
//负责部分文件的抓取 ?d>P
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**FileSplitterFetch.java "2#-xOCO  
*/ 2$SofG6D}  
package NetFox; i&}zcGC  
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import java.io.*; QKUBh-QFK  
import java.net.*; uK4'n+_>\  
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public class FileSplitterFetch extends Thread { 
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7 BnenHD  
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String sURL; //File URL +s/N@]5nW  
long nStartPos; //File Snippet Start Position AihL>a%  
long nEndPos; //File Snippet End Position qmue!Fv#g  
int nThreadID; //Thread's ID H/p-YtY  
boolean bDownOver = false; //Downing is over O#Zs3k  
boolean bStop = false; //Stop identical \CJx=[3(  
FileAccessI fileAccessI = null; //File Access interface bCE7hutl  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 7q2"b?|h  
{ Zy!)8<Cgm'  
this.sURL = sURL; ?sjZ13 SUa  
this.nStartPos = nStart; :cmI"Bo  
this.nEndPos = nEnd; aCYm$6LmA  
nThreadID = id; v0hfY   
fileAccessI = new FileAccessI(sName,nStartPos);//定位 w.T=Lzp  
} .j:.WnW  
@ (u?=x;  
},Y; (n'  
public void run() JXSqtk
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{ )v!lPpe8  
while(nStartPos < nEndPos && !bStop) %!HnGwv-  
{ SILvqm  
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try{ 3w<j:\i  
URL url = new URL(sURL); ,SJK  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); /n(bThDH  
httpConnection.setRequestProperty("User-Agent","NetFox"); fw:^Lyn9$  
String sProperty = "bytes="+nStartPos+"-"; \@}$Wjsl  
httpConnection.setRequestProperty("RANGE",sProperty); 0r$hPmvv8  
Utility.log(sProperty); 4
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InputStream input = httpConnection.getInputStream(); O"J.k&C<,  
//logResponseHead(httpConnection); "{ry 9?z  
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byte[] b = new byte[1024]; mBpsgm:g^  
int nRead; 4_m /_Z0x  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ]|$$:e^U9  
{ NW4 s'roP  
nStartPos += fileAccessI.write(b,0,nRead); 2YE]?!   
//if(nThreadID == 1) WKrZTPD'm  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 1$!RKqT  
} 
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Utility.log("Thread " + nThreadID + " is over!"); Am0.c0h
  
bDownOver = true; gh #w%g1g  
//nPos = fileAccessI.write (b,0,nRead); z$BnEd.y=:  
} P15*VPy  
catch(Exception e){e.printStackTrace ();} |YGiATD4DG  
} 18/
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} +&N&D"9A  
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//打印回应的头信息 ;&^"q{m  
public void logResponseHead(HttpURLConnection con) /6+%(f}7l  
{ 9;v"bcQ  
for(int i=1;;i++) nog\,NT  
{ *r?51
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String header=con.getHeaderFieldKey(i); + $a:X  
if(header!=null) Obc3^pV&  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Ae_ E;
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Utility.log(header+" : "+con.getHeaderField(header)); ;gW|qb+#)j  
else {O&liU4  
break;  wpdEI(  
} vYt:}$AE  
} 9c;lTl^4;  

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public void splitterStop() gAUQQ  
{ 1707  
bStop = true; 645C]l  
} y0&HXX#\  
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} F+$@3[Q`N  
@[b:([  
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/* lPN< rgg  
**FileAccess.java z3jzpmz  
*//文件访问(定位，写) y yR8VO{  
package NetFox; _
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import java.io.*; Dw ;vDK  
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public class FileAccessI implements Serializable{ Y6Qb_X:  
VUv.Tx]Z[  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 K9M.+d4  
RandomAccessFile oSavedFile; .@3u3i64'  
long nPos; !BikF4Y1L&  
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public FileAccessI() throws IOException u[|S*(P  
{ -Us% 
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this("",0); U?^|>cMr  
} P_g0G#`4  
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public FileAccessI(String sName,long nPos) throws IOException =XBXSW8)DJ  
{ x-#9i  
oSavedFile = new RandomAccessFile(sName,"rw"); Mh.eAM8_  
this.nPos = nPos; #DRtMrfat  
oSavedFile.seek(nPos); -*q2Y^A^l  
} bfI -!,  
u R%R]X  
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public synchronized int write(byte[] b,int nStart,int nLen) l(
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{ KC-aLq/  
int n = -1; kGqf@ I+  
try{ ,L:)ZZgN  
oSavedFile.write(b,nStart,nLen); [k=9 +0p  
n = nLen; }Z?[Ut  
} (l_de)N7  
catch(IOException e) r=||sZs  
{ rtF6Lg
 
e.printStackTrace (); <r`Jn49  
} >~>[}d;glw  
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return n; RF2XJJ  
} >,Bu^] C  
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} =l'_*B8  
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/* GXK?7S0H  
**SiteInfoBean.java <
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*/ +<WT$ddK=5  
package NetFox; KR(ftG'  
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public class SiteInfoBean { :tG".z  
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private String sSiteURL; //Site's URL 1WN93SQ=  
private String sFilePath; //Saved File's Path LHz<=]?@  
private String sFileName; //Saved File's Name W}_}<rlF  
private int nSplitter; //Count of Splited Downloading File HU+H0S~g  
_rJSkZO  
)tch>.EQ_  
public SiteInfoBean() 0i`Zy!  
{//nSplitter的缺省值为5 +5mkMZ  
//default value of nSplitter is 5 CscJy0dB  
this("","","",5); qm5pEort  
} 1O7ss_E  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Z|dZc wo  
{ WA5kX SdIb  
sSiteURL= sURL; ;l?(VqX_E  
sFilePath = sPath; NS;8&  
sFileName = sName; I_*>E
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this.nSplitter = nSpiltter; u.Yb#?  
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6lAo`S\)eX  
} )9Ojvp=#r:  
~(]DNXB8I`  
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public String getSSiteURL() 8HA=O?Cg  
{ j5^b~F%  
return sSiteURL; M':.b+xN  
} ZSt ww{Z
 
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*
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public void setSSiteURL(String value) ~At.V+  
{ 'oL[rO~j  
sSiteURL = value; Li^!OHro.  
} c6)zx b  
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/k"P4\P`+Q  
public String getSFilePath() %~2m$#)  
{ ^v|!(h\ZC  
return sFilePath; Hv*O9!cC  
} 'Pu;]sC  
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public void setSFilePath(String value) e"/X*xA  
{ rep"xV&|>o  
sFilePath = value; w!7/;VJ3d  
} ;rL$z;}8  
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public String getSFileName() =ApT#*D)o  
{ FQ)Ekss~C  
return sFileName; ".<p R} qp  
} e'&{KD,-T  
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public void setSFileName(String value) BZshTP[`  
{ 5xUPqW%3  
sFileName = value; wJkkc9Rh'(  
} 2]ljm]\l  
+]vl8, 4@  
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public int getNSplitter() [rsAY&.  
{ cA2]VL.r>C  
return nSplitter; # t Ki6u  
} V'/%)oU\"  
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public void setNSplitter(int nCount) N*>; '  
{ 7^=jv~>wP  
nSplitter = nCount; rnE'gH(V'  
} Su#1yw>  
} +-d>Sl (  
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/* U$bM:d  
**Utility.java )wd~639U  
*/ +ETw:i9!?  
package NetFox; C\D4C]/8  
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public class Utility { 0in6z  
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public Utility() 8 K!a:{  
{ +Wc[$,vk  
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do7{  
} xE_[=7=  
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//线程睡眠 b\Ub<pE  
public static void sleep(int nSecond) 1| DI'e[X  
{ c3dZ1v  
try{ +i =78  
Thread.sleep(nSecond); {o`5&EoM  
} [4yQ-L)]e  
catch(Exception e) a\E]ueVD2j  
{ _Ar,]v  
e.printStackTrace (); ;@hP*7Lm  
} r1]^#&V;MC  
} lc7]=,qyF  
qa0Zgn5q  
//日志 H l@rS  
public static void log(String sMsg) b}*hodzF  
{ f *vziC<m  
System.err.println(sMsg); eS
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} d+'+z %s%  
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Z*  

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public static void log(int sMsg) [&:oS35O  
{ n>UvRn.7kz  
System.err.println(sMsg); 7Wu2gky3  
} jBbc$|O4SY  
} \ PqV|
 
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/* <T]kpP<lC  
**TestMethod.java )FLp
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*/ ;r']"JmF,  
package NetFox; [>86i  
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public class TestMethod { e|P60cd /  
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public TestMethod() p\K5B,  
{ ///xx/weblogic60b2_win.exe 4dP_'0]9A:  
try{ )LG/n  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); {ex]_V>  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); rIb{=';  
SiteFileFetch fileFetch = new SiteFileFetch(bean); :.,I4>b2  
fileFetch.start(); ghl9gFFj  
} +#no$m.bH  
catch(Exception e){e.printStackTrace ();} 3'wBX  
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} x@=7M'vr%  
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public static void main(String[] args) rgCId@R  
{ eMwf'*#  
new TestMethod(); r[x7?cXsW  
} 5tL6R3  
} *QX$Mo^E  
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