http断点续传简单实现（java)

/* ,b!!h]t  
**SiteFileFetch.java `vs= CYs  
*/ O]rAo  
package NetFox; Bwv@D4bii  
import java.io.*; h&d%#6mB  
import java.net.*; Qwl=/<p1  
}
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public class SiteFileFetch extends Thread { ."9t<<!  
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SiteInfoBean siteInfoBean = null; //文件信息Bean Fr/3Qp@S  
long[] nStartPos; //开始位置 ^~~&[wY  
long[] nEndPos; //结束位置 .XD7};g  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 *{/ ww9fT  
long nFileLength; //文件长度 OL+dx`Y  
boolean bFirst = true; //是否第一次取文件 $U=E7JO  
boolean bStop = false; //停止标志 q0|u vt"  
File tmpFile; //文件下载的临时信息 h&Thq52R  
DataOutputStream output; //输出到文件的输出流 >'IFr9&3  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 242dT/j  
public SiteFileFetch(SiteInfoBean bean) throws IOException ($a ?zJr  
{ :EOx>Pf_9)  
siteInfoBean = bean; 9$[I~I#z  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 0uX"KL]Elf  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); v^;-w~?3  
if(tmpFile.exists ()) WXz'H),
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{ |X&.+RI  
bFirst = false; c`:
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read_nPos(); {z)&=v@  
} ~3k& =3d]  
else `m
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{ BQYj"Wi  
nStartPos = new long[bean.getNSplitter()]; 1 o<l;:  
nEndPos = new long[bean.getNSplitter()]; Gok8:,  
} .yz-o\,gF%  
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} ftBbO8e  
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public void run()  LW?Zd=  
{ 5rG&Z5  
//获得文件长度 >r Nff!Ow
 
//分割文件 en\shc{R]`  
//实例FileSplitterFetch [hy:BV6H+  
//启动FileSplitterFetch线程  y!6+jrI  
//等待子线程返回 !3~VoNh,  
try{ :uM2cc^  
if(bFirst) `x;8,7W;B  
{ Z2z"K<Z W  
nFileLength = getFileSize(); :,.g_@wvG  
if(nFileLength == -1)  U)oH@/q  
{ eF8!}|*N  
System.err.println("File Length is not known!"); k~|nU  
} oicett=5  
else if(nFileLength == -2) $`q8-+{  
{ S<n3wR"^  
System.err.println("File is not access!"); rE?(_LI  
} %(4G[R[  
else sA18f2  
{ BKoc;20;  
for(int i=0;i<nStartPos.length;i++) M1._{Jw5  
{ StUiL>9T#  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); aQax85  
} x
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for(int i=0;i<nEndPos.length-1;i++) ; n2|pC^  
{ 4m++>q  
nEndPos = nStartPos[i+1]; c"ukV_6~J  
} m35Blg34  
nEndPos[nEndPos.length-1] = nFileLength; j7;v'eA`;7  
} bH7[6#
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} @Z$`c{V<  
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//启动子线程 %hK?\Pg3=E  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; G~ZDXQ>5CP  
for(int i=0;i<nStartPos.length;i++) < 4DWH  
{ f~Dl;f~H_;  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), s{q)m@  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 
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nStartPos,nEndPos,i); S=O/W(ZB  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); +Q, 0kv  
fileSplitterFetch.start(); G'XlsyaWrb  
} &J|3uY,'j  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 02X~' To"  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); s~$kzEtjjU  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", L1
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nEndPos = " + nFileLength); ie$QKoE  
// fileSplitterFetch[nPos.length-1].start(); bo&!oY#  
8WWRKP1V  
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//等待子线程结束 woZ'T  
//int count = 0; ErF;5ec  
//是否结束while循环 ]I"
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boolean breakWhile = false; R!xs;|]  
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8?W!U*0aS  
while(!bStop) rWbuoG+8  
{ =mCUuY#  
write_nPos(); P]2M  
Utility.sleep(500); [(tgoh/  
breakWhile = true; iR4CY-  
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for(int i=0;i<nStartPos.length;i++) '6{q;Bxo  
{ ?[Q;275  
if(!fileSplitterFetch.bDownOver) yY*OAC  
{ ,*0>CBJvv  
breakWhile = false; 3a#637%  
break; Z5Ao3O@  
} 6KhHS@Z  
} ?7G?uk]3,@  
if(breakWhile) .CI]8O"3y  
break; 7&NRE"?G  
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//count++; MLmc]nL=  
//if(count>4) r0QjCFSF=  
// siteStop(); iUA2/ A  
} +n9&q#ah  
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*%ZfE,bu8<  
System.err.println("文件下载结束！"); 9`.b   
} ci
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catch(Exception e){e.printStackTrace ();} 0"u*Kn  
} 9R>A,x(
  
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S=[K/Kf-  
//获得文件长度 NNutpA}s  
public long getFileSize() D.qbzJz  
{ t>&$_CSWK  
int nFileLength = -1; <3HW!7Ad1  
try{ o'myo.k{  
URL url = new URL(siteInfoBean.getSSiteURL()); /c/!13|  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); xi;SKv;p  
httpConnection.setRequestProperty("User-Agent","NetFox"); 3X0^xUA6  
+ls *04  
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int responseCode=httpConnection.getResponseCode(); K"Nq_Ddwd  
if(responseCode>=400) kp<9o!?)  
{ $g#X9/+<  
processErrorCode(responseCode); o [ar.+[  
return -2; //-2 represent access is error )^%,\l-!  
} `Up<;  
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String sHeader; yuFuYo&[?v  
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for(int i=1;;i++) O|7q,bEm^  
{ *PL+)2ob  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); A!iH g__/t  
//Utility.log(in.readLine()); J[LGa:``  
sHeader=httpConnection.getHeaderFieldKey(i); s}|IRDpp  
if(sHeader!=null) ]o,)#/' $  
{ (jY.S|%  
if(sHeader.equals("Content-Length")) An]*J|nFIY  
{ c~RElL  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); N@Slc 0  
break; z_JZx]*/  
} Ku,Efr  
} j?w7X?1(  
else qf
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break; zb9d{e  
} .^JID~<?#  
} 0C3Yina9 *  
catch(IOException e){e.printStackTrace ();} 0pkU1t~9  
catch(Exception e){e.printStackTrace ();} rK=[&
k  
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Utility.log(nFileLength); vNE91  
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return nFileLength; Pq7YJ"Z?:  
} x(mY$l,il  
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//保存下载信息（文件指针位置） S'3l<sY  
private void write_nPos() C=PBF\RkKu  
{ ,3fw"P$  
try{ $: Qi9N
 
output = new DataOutputStream(new FileOutputStream(tmpFile)); $)7-wCl</  
output.writeInt(nStartPos.length); Y;#P"-yH  
for(int i=0;i<nStartPos.length;i++) u{>5  
{ ,C=Fgxw(  
// output.writeLong(nPos); ?FMHK\  
output.writeLong(fileSplitterFetch.nStartPos); I9>1WT<Yy  
output.writeLong(fileSplitterFetch.nEndPos); (#Y2H  
} y\x!Be;6Z.  
output.close(); 5vP*oD  
} ]^Q`CiKd  
catch(IOException e){e.printStackTrace ();} /1MO]u\  
catch(Exception e){e.printStackTrace ();}  d(v )SS  
} p(Qm\g<  
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5%4:)s{4|  
//读取保存的下载信息（文件指针位置） 1YM04*H  
private void read_nPos() ?J<4IvL/  
{ pazFVzT  
try{ y@_4OkR@  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); `+* Mr  
int nCount = input.readInt(); .`,YUr$.  
nStartPos = new long[nCount]; PeE'#&wn  
nEndPos = new long[nCount]; MR+ndB<  
for(int i=0;i<nStartPos.length;i++) C=hE@  
{ gCwg ;c-  
nStartPos = input.readLong(); pQEHWq"Q  
nEndPos = input.readLong(); k#&y
  
} V (X)Qu@R  
input.close(); I{1w8m4O6  
} ?}lCS7&  
catch(IOException e){e.printStackTrace ();} vx-u+/\  
catch(Exception e){e.printStackTrace ();} ]Fjz+CGg  
} jRq>Sz{8  
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private void processErrorCode(int nErrorCode) L'['7  
{ YjG0: 9  
System.err.println("Error Code : " + nErrorCode); !_V*VD  
} n|^-qy'w  
jkPXkysm  
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//停止文件下载 +F67g00T|  
public void siteStop() 1>|p1YZ"  
{ pGsVO5M?  
bStop = true; t/q\Ne\\,  
for(int i=0;i<nStartPos.length;i++) wmT3 >  
fileSplitterFetch.splitterStop(); 9prG@  
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} #UGbSOoCtn  
} Dy8Go4
  
//负责部分文件的抓取 QR^pu.k@  
**FileSplitterFetch.java -G*u2i_*  
*/ u,'c:RMV  
package NetFox; @];Xbbw+c  
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import java.io.*; :!aFfb["  
import java.net.*; {`1zVTp[<  
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public class FileSplitterFetch extends Thread { SZyPl9.b  
9Uk9TG5  
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String sURL; //File URL 9K%E+_7b  
long nStartPos; //File Snippet Start Position %7L'2/Y2x  
long nEndPos; //File Snippet End Position ,@>B#%Nz  
int nThreadID; //Thread's ID xi|iV1A  
boolean bDownOver = false; //Downing is over NP|U |zn  
boolean bStop = false; //Stop identical V:IoeQ]-  
FileAccessI fileAccessI = null; //File Access interface 0 J ANj  
.>H7i`1D`  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 2>s:wABb /  
{ c.d*DM}W  
this.sURL = sURL; 7Qq>?H -  
this.nStartPos = nStart; O0~[]3Y[=  
this.nEndPos = nEnd; 1_<'S34  
nThreadID = id; )b5MP1H  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 xx41Qw>\W  
} I-+D+DhRx  
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public void run() y+X%qT
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{ \d v9:X$  
while(nStartPos < nEndPos && !bStop) 3pl.<;9r  
{  BeP0lZ  
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try{ V_Y SYG9f  
URL url = new URL(sURL); kbOo;<X9A  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); oBIKtS*L  
httpConnection.setRequestProperty("User-Agent","NetFox"); LoNz 1KJL  
String sProperty = "bytes="+nStartPos+"-"; qzV:N8+,`  
httpConnection.setRequestProperty("RANGE",sProperty); n {^D_S  
Utility.log(sProperty); 9I.="b=J)  
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}X}fX#[  
InputStream input = httpConnection.getInputStream(); Rrk3EL  
//logResponseHead(httpConnection); j63w(Jv/  
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byte[] b = new byte[1024]; 3O$Q>.0w/  
int nRead; LD#]"k  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ~ dmyS?Or  
{ ]LNP"vi;  
nStartPos += fileAccessI.write(b,0,nRead); &K|CH? D  
//if(nThreadID == 1) uvZ|6cM  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); +ZXk0sP_<  
} QiB:K Pz[  
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* 4
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Utility.log("Thread " + nThreadID + " is over!"); Q<Utwk?nL  
bDownOver = true; )I`B+c:  
//nPos = fileAccessI.write (b,0,nRead); 8CwgV  
} F&I^bkvh  
catch(Exception e){e.printStackTrace ();} ={8ClUV#  
} 7e>n{rl  
} \%rX~UhZ=  
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//打印回应的头信息 dN;C-XF3s  
public void logResponseHead(HttpURLConnection con) YV 2T$#7u  
{ mI?AI7DqK  
for(int i=1;;i++) O`Nzn~),x  
{ _ jF, k>F  
String header=con.getHeaderFieldKey(i); jD'\\jAUdm  
if(header!=null) I`zn#U'  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); F0]NtKaH  
Utility.log(header+" : "+con.getHeaderField(header)); MhWmY[  
else 2NqlE  
break; 1kvBQ1+  
} lP\7=9rh^x  
} jt=mK,%  
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public void splitterStop() .@.O*n#K  
{ .$L'Jt
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bStop = true; &mp=jGR  
} VuPa'2  
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} }e&   
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/* 7[.aAGTZ;  
**FileAccess.java MCjf$pZN]  
*//文件访问(定位，写) MXq+aS{  
package NetFox; <`+U B<K  
import java.io.*; Myg &H(~  
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public class FileAccessI implements Serializable{ )C|[j@MD  
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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 xf_NHKZ)  
RandomAccessFile oSavedFile; ,-rOfk\u  
long nPos; 2I3MV:5  
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public FileAccessI() throws IOException iOYC1QFi?  
{ >;-.rJFr
 
this("",0); XJ^dX]4  
} q@1b{q#C5  
PJ5~,4H-4  
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public FileAccessI(String sName,long nPos) throws IOException (J I4ibP  
{ z/dpnGX  
oSavedFile = new RandomAccessFile(sName,"rw"); (&H-v'a}3  
this.nPos = nPos; k)U9%Pr  
oSavedFile.seek(nPos); dUegHBw_`R  
} >> yK_yg  
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4! ]28[2B6  
public synchronized int write(byte[] b,int nStart,int nLen) He @d~9M  
{ ve|ig]$5g<  
int n = -1; c5Fl:=h  
try{ [Q9#44@{S;  
oSavedFile.write(b,nStart,nLen); Gi]R8?M  
n = nLen; ' 5`w5swbc  
} M
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catch(IOException e) 0'j/ 9vm  
{ X` r~cc  
e.printStackTrace (); rWsUWA T*  
} 4BF \-lq~  
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return n; 'b1k0 9'  
} jRdmQmTJ  
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} CNU,\>J@$  
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/* `_"F7Czn  
**SiteInfoBean.java F%|F-6  
*/ :qlc
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package NetFox; l5
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public class SiteInfoBean { olLVT<  
vT1StOx<V  
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private String sSiteURL; //Site's URL LeP;HP|  
private String sFilePath; //Saved File's Path 5ub|r0&M  
private String sFileName; //Saved File's Name 4zo^ b0v  
private int nSplitter; //Count of Splited Downloading File Yf&P|I
iw  
%m
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public SiteInfoBean() 9szUN;:ZZ  
{//nSplitter的缺省值为5 k4i*80  
//default value of nSplitter is 5 |!Ryl}Oi  
this("","","",5); LZR x>q^  
} SLsw '<  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) AT{rg/oSf  
{ UA0j#  
sSiteURL= sURL; ~6nY5  
sFilePath = sPath; THN//}d  
sFileName = sName; A.YXK%A%  
this.nSplitter = nSpiltter; f$y`tT %o  
u2 a#qU5*  
3bU(ea^e$  
} 'r0kX||  
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](@HPAG]  
public String getSSiteURL() K`vc&uf  
{ &2P=74\=  
return sSiteURL; I5%#A/|z  
} /XVjcD66c  
:HiAjaA1pg  
rWMG6+Scb  
public void setSSiteURL(String value) E:$EK_?:t  
{ wJAJ
/  
sSiteURL = value; _TbQjE&6  
} 3QF/{$65!  
!E@4^A80\W  
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public String getSFilePath() qG)M8xk  
{ G2y
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return sFilePath; )Vf!U"  
} B?gFFU61  
Q94Lq~?YF  
7cQFH@SC  
public void setSFilePath(String value) WcHL:38  
{ )q|a
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sFilePath = value; PP-U.  
} fMm.V=/+  
+bDBc?HZ{$  
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public String getSFileName() @>Bgld&vl  
{ :9~LY
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return sFileName; dJ(<zz+;b  
} j;yKL-ycB  
r "uQ|
 
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public void setSFileName(String value) +l27y0>t  
{ HT%'dZ1  
sFileName = value; w.o>G2u  
} 90Bn}@t=Q  
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public int getNSplitter() 7U1^=Y@t}  
{ 1:;S6
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return nSplitter; N?s`a;Q[=  
} 34F;mr"yp  
5ktFL<^5T  
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public void setNSplitter(int nCount) 8pXqgIbmb  
{ -P:o ^_)g  
nSplitter = nCount; 83!{?EPE  
} 85:KlBe%+  
} po@Agyg5  
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8RA  
/* lBzfBmEB  
**Utility.java qM18Ji*  
*/ Oq*;GR(Q  
package NetFox; H7 "r^s]D  
:MihVLF  
: "^/?Sd  
public class Utility { 2jF}n*[OW  
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public Utility() 6~OJB!  
{ 8ly6CP+^B  
wvmcD%   
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} ?vP6~$*B  
`96MXP  
//线程睡眠 WP{U9YF2  
public static void sleep(int nSecond) [jR>.H'  
{ /?NfU.+K  
try{ {>Hn:jW<.  
Thread.sleep(nSecond); EXsVZg"#  
} A,EuUp  
catch(Exception e) y~'%PUN  
{ y@(EGfI  
e.printStackTrace (); I9e3-2THfj  
} O^n\lik  
} WmOu#5*;  
 7LB%7~{<  
//日志 ^Y%<$I
FG  
public static void log(String sMsg) WfHa  
{ ibn\&}1  
System.err.println(sMsg); |\xTcS|d  
} U|<>xe*|%  
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public static void log(int sMsg) Yx&d\/9  
{
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System.err.println(sMsg); N2 t`  
} 22*~CIh~x  
} 'w=aLu5dY  
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 @{Dfro  
/* Tb!FO"o  
**TestMethod.java ?zf3AZ9  
*/ x`Wb9[u8  
package NetFox; ]Ot=At  
9fWR8iV  
jZH4]^De  
public class TestMethod { '#>Fe`[  
>[&ser  
P@Fx6  
public TestMethod() $3gM P+  
{ ///xx/weblogic60b2_win.exe D< kf/hj  
try{ \}\# fg  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ,J
=lHj  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); h/2@4XKj  
SiteFileFetch fileFetch = new SiteFileFetch(bean); "$P/ek  
fileFetch.start(); ; K,5qs  
} 3dJiu  
catch(Exception e){e.printStackTrace ();} m2&Vm~Py6b  
$$SJLV
  
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} 0+[3>Ny0  
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^/cqE[V~,  
public static void main(String[] args) [e_<UF@A*  
{ )L7[;(gQ  
new TestMethod(); *
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} s8'!1rHd  
} CpK:u! Dn  
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