http断点续传简单实现（java)

/* Cc+
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**SiteFileFetch.java s@&`f{  
*/ 3}TaF~  
package NetFox; >Ea8G,  
import java.io.*; ~
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import java.net.*; :~b3^xhc^  
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public class SiteFileFetch extends Thread { f2Klt6"9  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ZXqSH${Tp  
long[] nStartPos; //开始位置 B8.P
n  
long[] nEndPos; //结束位置 ] bM)t<  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 \rx3aJl  
long nFileLength; //文件长度 ;(f)&Yom  
boolean bFirst = true; //是否第一次取文件 .*@;@06?
 
boolean bStop = false; //停止标志 FOv=!'So  
File tmpFile; //文件下载的临时信息 *W4m3Lq  
DataOutputStream output; //输出到文件的输出流 9_
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） J`peX0Stl  
public SiteFileFetch(SiteInfoBean bean) throws IOException 3 R=,1<  
{ `YFtL  
siteInfoBean = bean; 4x{0iav  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 5L+>ewl  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); oRm L {UDZ  
if(tmpFile.exists ()) 0LPig[  
{ 3QV*%  
bFirst = false; nHnK)9\N  
read_nPos(); $:=A'd2  
} 7]U"Z*  
else h;C5hU4P  
{ L"E7#}  
nStartPos = new long[bean.getNSplitter()]; 54gBJEhg  
nEndPos = new long[bean.getNSplitter()]; 0Iw
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} ?Nup1!D  
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} _7Rr=_1}  
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public void run() iQ tNAj  
{ dT`
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//获得文件长度 6CV* Z\b  
//分割文件 |jQ:~2U|  
//实例FileSplitterFetch =}lh_  
//启动FileSplitterFetch线程 3AHlSX  
//等待子线程返回 G! ]k#.^A,  
try{ WQ~;;.v#  
if(bFirst) <Y*+|T+&d  
{ :=}US}H$  
nFileLength = getFileSize(); `>gd&u  
if(nFileLength == -1) K$&s=Hm  
{ ~xA-V4.  
System.err.println("File Length is not known!"); o9|nJ;  
} X^T:8npxt  
else if(nFileLength == -2) (X $=Q6  
{ %zA;+s$l  
System.err.println("File is not access!"); q 0$,*[PH  
} sNj)ZWgd>  
else 3*]eigi)  
{ *S]Ci\{_  
for(int i=0;i<nStartPos.length;i++) Q}1 R5@7  
{ [
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); &R[ Mc-2  
} -d~4A  
for(int i=0;i<nEndPos.length-1;i++) FK:;e lZ  
{ dU6ou'pf  
nEndPos = nStartPos[i+1];
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} 2"0es40;0  
nEndPos[nEndPos.length-1] = nFileLength; 7Fz
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} Of-Rx/
 
} t|H^`Cv6  
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//启动子线程 9*2[B"5  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; C\3y
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for(int i=0;i<nStartPos.length;i++) w&$`cD  
{ 1_o],?Q  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), fRrvNj0{V  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), w:%o?pKet1  
nStartPos,nEndPos,i); hXfQ)$J  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); H(R1o~  
fileSplitterFetch.start(); I CZ4A{I  
} CpA|4'#  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), qS403+Su1=  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); dq7x3v^"ZG  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", bHPYp5UwN  
nEndPos = " + nFileLength); ;'?l$ ._  
// fileSplitterFetch[nPos.length-1].start(); )`SES."  
!Nu<xq@!  
?p9VO.^5  
//等待子线程结束 fdxLAC  
//int count = 0; 1Q
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//是否结束while循环 RS"H8P4W  
boolean breakWhile = false; e>7]w,*|  
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while(!bStop) 2VF%@p  
{ B268e  
write_nPos(); FYOD Upn  
Utility.sleep(500); ^@I   
breakWhile = true; pM^9c7@!:  
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for(int i=0;i<nStartPos.length;i++) <A<{,:5C  
{ (hTCK8HK  
if(!fileSplitterFetch.bDownOver) x4g3rmp  
{ NS9B[*"Jl  
breakWhile = false; wHsYF`  
break; 3Vsc 9B"w  
} dA-2%uJ  
} nIAx2dh?  
if(breakWhile) 8yRJD[/S  
break; r>dwDBE  
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f_wvZ&  
//count++; *"R|4"uy  
//if(count>4) 2Gz}T _e  
// siteStop(); * 1T&  
} -|kA)M[  
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System.err.println("文件下载结束！"); z3`-plE  
} I'\kFjc  
catch(Exception e){e.printStackTrace ();} QZ4v/
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} n?A6u\sQ  
+~'865{  
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//获得文件长度 P1zKsY,l$<  
public long getFileSize() rW0kA1=E  
{ 3j,Q`+l/6d  
int nFileLength = -1; A54N\x,  
try{ Dakoqke  
URL url = new URL(siteInfoBean.getSSiteURL()); >C7r:%  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); xgABpikC^  
httpConnection.setRequestProperty("User-Agent","NetFox"); rE iKi  
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int responseCode=httpConnection.getResponseCode(); 3Th'paMG  
if(responseCode>=400) 09dK0H3(  
{ m/v9!'cMI  
processErrorCode(responseCode); /4tj3B,  
return -2; //-2 represent access is error gfX\CSGy  
} (H)2s Y  
4 d;|sI@  
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String sHeader; QN@CPuy  
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&?VQ,+[<
 
for(int i=1;;i++) tDSJpW'd  
{ kV?y0J.  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 9w"h  
//Utility.log(in.readLine()); MA;1;uI,  
sHeader=httpConnection.getHeaderFieldKey(i); U2{ dN>  
if(sHeader!=null) "Weg7mc#  
{ +hvO^?4j  
if(sHeader.equals("Content-Length")) `1'6bp`Z  
{ i\1TOP|h  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); T~QWRBO  
break; TS/.`.gT  
} P6!jRC"52'  
} X'%E\/~u  
else M9EfU  
break; Lk~ho?^`  
} 8*8Zc/{  
} pF&(7u  
catch(IOException e){e.printStackTrace ();} pcau}5 .  
catch(Exception e){e.printStackTrace ();} !g Z67  
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Utility.log(nFileLength); Sczc5FG  
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return nFileLength; 1=#q5dZ]  
} /3;4#:Kkw  
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//保存下载信息（文件指针位置） 
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private void write_nPos() yMyE s8  
{ $SM#< @  
try{ O?U'!o=  
output = new DataOutputStream(new FileOutputStream(tmpFile)); XID<(HBA"!  
output.writeInt(nStartPos.length); |3F02
 
for(int i=0;i<nStartPos.length;i++) A6GE,FhsG  
{ cU ?0(z7  
// output.writeLong(nPos); M(jgd  
output.writeLong(fileSplitterFetch.nStartPos); GN
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output.writeLong(fileSplitterFetch.nEndPos); fNb`X  
} ,$;yY)x7U  
output.close(); , FhekaA  
} '6Ay&A3N]  
catch(IOException e){e.printStackTrace ();} CF+_/s#j^  
catch(Exception e){e.printStackTrace ();} 350_CN,  
} u`y><w4i  
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//读取保存的下载信息（文件指针位置） ObLly%|i  
private void read_nPos() I"Ms-zs  
{ #?q&r_@@  
try{ j;s"q]"x]  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); !6s"]WvF  
int nCount = input.readInt(); b'J'F;zh>  
nStartPos = new long[nCount]; t=_J9|  
nEndPos = new long[nCount]; )jkXSTZ  
for(int i=0;i<nStartPos.length;i++) dYSr4pb  
{ \cC%!4  
nStartPos = input.readLong(); I?"q/Ub~h  
nEndPos = input.readLong(); Vl%^H[]  
} ._8KsuJG  
input.close(); A]YVs  
} \]P!.}nX#  
catch(IOException e){e.printStackTrace ();} _Dym{!t  
catch(Exception e){e.printStackTrace ();} A$#p%yb  
} 6fd+Q /  
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private void processErrorCode(int nErrorCode) jov:]Bic  
{ }| J79s2M  
System.err.println("Error Code : " + nErrorCode); {Z3dF)>  
} |~'IM3Jw(Y  
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j'%$XvI  
//停止文件下载 z|asa*  
public void siteStop()
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{ )t$,e2FY  
bStop = true; @fs`=lL/  
for(int i=0;i<nStartPos.length;i++) vz^<YZMu  
fileSplitterFetch.splitterStop(); q-]`CW]n  
*H?!;u=8  
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} N5]0/,I
}  
} }b=}uiR#  
//负责部分文件的抓取 :T]o)  
**FileSplitterFetch.java xEf'Bmebk  
*/ VYt!U
  
package NetFox; (>`5z(X  
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import java.io.*; {Zh>mHW3  
import java.net.*; G 16!eDMt  
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public class FileSplitterFetch extends Thread { qHNE8\9  
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String sURL; //File URL ua5OGx  
long nStartPos; //File Snippet Start Position Kv.>Vf.T}_  
long nEndPos; //File Snippet End Position .so[I
 
int nThreadID; //Thread's ID jy giG&H  
boolean bDownOver = false; //Downing is over =+-Yxh|*  
boolean bStop = false; //Stop identical jeGj<m  
FileAccessI fileAccessI = null; //File Access interface ]wKzE4Z/  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Nluv/?<  
{ Pcu#lWC$  
this.sURL = sURL; $aN-Y?U%  
this.nStartPos = nStart; N@Y ljz|  
this.nEndPos = nEnd; )RO<o O  
nThreadID = id; <$F\Nk|x  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 KN tt  
} JJ{9U(`_y6  
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public void run() p98~&
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{ $BFvF ,n  
while(nStartPos < nEndPos && !bStop) ?t+5s]  
{ ow0!%|fO  
U Z|HJ8_  
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try{ hQ(q
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URL url = new URL(sURL); 'ihhoW8  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Qu}W/j|3  
httpConnection.setRequestProperty("User-Agent","NetFox"); 1Wm)rXW[x  
String sProperty = "bytes="+nStartPos+"-"; *+uHQgn(  
httpConnection.setRequestProperty("RANGE",sProperty); RRGWC$>?  
Utility.log(sProperty); FBpH21|/y  
1gmt2>#v%  
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InputStream input = httpConnection.getInputStream(); d
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//logResponseHead(httpConnection); J|X 6j&-  
$ &P>r  
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byte[] b = new byte[1024]; A |3tI  
int nRead; G
7)Fk%>  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) p=C%Hmd5E  
{ m;D- u>o  
nStartPos += fileAccessI.write(b,0,nRead); Wm);C~Le  
//if(nThreadID == 1) $KLD2BAL  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); I!>\#K  
} {X[ HCfJd  
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Utility.log("Thread " + nThreadID + " is over!"); `ORECg)  
bDownOver = true; e"'#\tSG  
//nPos = fileAccessI.write (b,0,nRead); zG
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} n+BJxu?  
catch(Exception e){e.printStackTrace ();} 3/b;7\M  
} +,yK;^b  
} zoDH` h_  
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//打印回应的头信息 I j$lDJS  
public void logResponseHead(HttpURLConnection con) ,_X/Gb6)  
{ zfwS  
for(int i=1;;i++) &BtK($  
{ N.
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String header=con.getHeaderFieldKey(i); Zum0J{l h  
if(header!=null) +=]!P#  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Hewd4k  
Utility.log(header+" : "+con.getHeaderField(header)); zCOgBT~p  
else X^\>:<  
break; t9Y=m6  
} cwm_nQKk  
} b:R-mg.VT{  
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public void splitterStop() "H&"(=  
{ j:}DBk  
bStop = true; H-3Eo
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} B%KG3]  
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} w|CZ7|6  
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/* N<QjdD&  
**FileAccess.java DhX#E&  
*//文件访问(定位，写) A<6%r7&B'  
package NetFox; q~@]W=  
import java.io.*; eeHP&1= 7  
6<'rG''  
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public class FileAccessI implements Serializable{ <H
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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 `xz<>g9e  
RandomAccessFile oSavedFile; 6Z`R#d #I  
long nPos; >7roe []-|  
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public FileAccessI() throws IOException *]h`KxuO  
{ }hYZ" A~  
this("",0); $''9K  
} +rIL|c}J  
})w*m  
7HVZZ!>~  
public FileAccessI(String sName,long nPos) throws IOException kGL1!=>  
{ l^d[EL+  
oSavedFile = new RandomAccessFile(sName,"rw"); +4\U)Z/\  
this.nPos = nPos; S}f?.7  
oSavedFile.seek(nPos); =C
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} 1yV: qp  
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sz @p_Z/  
public synchronized int write(byte[] b,int nStart,int nLen) }gkM^*$:%  
{ <" @zn  
int n = -1; vsL[*OeI  
try{ ?88`fJ@tk?  
oSavedFile.write(b,nStart,nLen); UxD5eJJ  
n = nLen; Kf 2jD4z}  
} fK&e7j`qO  
catch(IOException e) @:tj<\G]  
{ G&;j6<hl  
e.printStackTrace (); be e5  
} XyMG.r-,  
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,*]d~Y  
return n; BSq)RV/3  
} Z_gC&7+  
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} *cTO7$\[  
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`:O\dN>ON  
/* eUl/o1~mXa  
**SiteInfoBean.java w#N?l!5  
*/ AF43$6KZP$  
package NetFox; YUQtMf9  
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public class SiteInfoBean { kkvtB<<Y  
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private String sSiteURL; //Site's URL dr{y0`CCN  
private String sFilePath; //Saved File's Path NNG}M(/V  
private String sFileName; //Saved File's Name hh~n#7w~IR  
private int nSplitter; //Count of Splited Downloading File g\GdkiI
j  
+>7$4`Nb2  
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public SiteInfoBean() :Vg}V"QR  
{//nSplitter的缺省值为5 ?3Ij*}
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//default value of nSplitter is 5 1!p/6  
this("","","",5); sA9&/p/  
} w62=06`@  
FFEfp.T1M  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) j<pw\k{i  
{ PN$ .X"D8  
sSiteURL= sURL; 5FC4@Ms`  
sFilePath = sPath; dSIH9D  
sFileName = sName; 4R>zPEo  
this.nSplitter = nSpiltter; ig0u^BC  
9umGIQHnil  
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} t ]c{c#N/  
kllQca|$4  
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public String getSSiteURL() -{|`H[nmD  
{ %;z((3F  
return sSiteURL; IGFGa@C  
} +TeFt5[)h  
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public void setSSiteURL(String value) {OT:3SS7  
{ j1Yq5`ia  
sSiteURL = value; 7.<^j[?  
} WW@"Z}?k  
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n  
}tST)=M`  
public String getSFilePath() DE{h
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{ 2aNT#J"_  
return sFilePath; i(2y:U3[@  
} TTI81:fku  
++[5q+b  
]*%+H|l  
public void setSFilePath(String value) q]4pEip  
{ Jd 3@cLCe-  
sFilePath = value; KA]*ox6j;  
} NB8&   
v.Ogf5  
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public String getSFileName() ,*,sw:=2  
{ (N~$x  
return sFileName; H*e'Cs/  
} ro| vh\y  
?~ULIO'  
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public void setSFileName(String value) WXUkuO  
{ t Y1Et0  
sFileName = value; e(\I_  
} |ek ak{js  
T|'&K:[TJ  
6`nR5fh  
public int getNSplitter() -
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{ M^SuV  
return nSplitter; KS>$`ax,
  
} Iz\1
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4L:>4X[T  
public void setNSplitter(int nCount) $Tl<V/  
{ `ti8-  
nSplitter = nCount; #1Z7&#R/  
} Ky9W/dCR  
} Q</h-skLZ  
H7IW"UkBR  
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/* Enj_tJs  
**Utility.java |XcH]7Ai"  
*/ LdWc X`K  
package NetFox; fD6GQ*  
5:gj&jt;)7  
3IyZunFT  
public class Utility { 9Q[>.):  
W);W.:F  
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public Utility() fi=?n{e'  
{ sv=^k(d3  
;QPy:x3  
1X:&*a"5  
} 05)|"EX)  
j.& ;c'V$.  
//线程睡眠 ~gt3Om
h  
public static void sleep(int nSecond) P6HGs? *  
{ W78o*z[O  
try{ $^$ECDOTB  
Thread.sleep(nSecond); NhDA7z`b'J  
} [$:@X V(  
catch(Exception e) QNJ\!+,HV  
{ SsRVd^=;x  
e.printStackTrace (); UPO^V:.R
4  
} kH2oK:lN  
} k`@w(HhS  
,i![QXZ  
//日志 Lh!z>IWjOG  
public static void log(String sMsg) \\s?B K  
{ @LC~*_y   
System.err.println(sMsg); s!`H  
} T/Q==Q{W:  
u\w2S4c  
LaT8l?q q  
public static void log(int sMsg) AA.Ys89V  
{ V0T<eH<  
System.err.println(sMsg); @#CF".fuN>  
} WVkG2  
} fp-m.d:|  
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fO+UHSC  
/* pj@Yqg/  
**TestMethod.java c.-cpFk^L&  
*/ z.j4tc9F/5  
package NetFox; wzbz}P>  
/Mx.:.A&$  
1W0.Ufl)  
public class TestMethod { &58 {  
OsB?1;:  
r hZQQOQ  
public TestMethod() r8F{A6iN  
{ ///xx/weblogic60b2_win.exe D2Vv\f  
try{ uYabJqV  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); HoV{Uzm  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Vp\80D&
  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 3M
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fileFetch.start(); _ Q{T';  
} /t$*W\PL@  
catch(Exception e){e.printStackTrace ();} IQ=CNby:  
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} C~{xL>I  
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public static void main(String[] args) !2#\| NJk  
{ 7 TmK  
new TestMethod(); @|E;}:?u  
} r)c+".0d^  
} ,YQ=Zk)w  
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