http断点续传简单实现（java)

/* U(.Ln@sq  
**SiteFileFetch.java ->$Do$  
*/ ^Jsx^?  
package NetFox; jt=mK,%  
import java.io.*; r1JKTuuo
 
import java.net.*; ?neXs-'-p  
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public class SiteFileFetch extends Thread { -05#/-Z=  
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SiteInfoBean siteInfoBean = null; //文件信息Bean h@@2vs2  
long[] nStartPos; //开始位置 D3|y|Dr  
long[] nEndPos; //结束位置 @e3O=_m-  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 8v5cQ5Lc  
long nFileLength; //文件长度 ##EMJ
i  
boolean bFirst = true; //是否第一次取文件 [f&ja[m q  
boolean bStop = false; //停止标志 ~UEft  
File tmpFile; //文件下载的临时信息 ^4h/6^b0c  
DataOutputStream output; //输出到文件的输出流 <jY"+@rF  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ggXg4~WL  
public SiteFileFetch(SiteInfoBean bean) throws IOException z3[ J>  
{ |ILj}4ZA7  
siteInfoBean = bean; \Om.pOz  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); yiWBIJ2Wu9  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); r`HtN{6r  
if(tmpFile.exists ()) ezgP\ct  
{ ][I}yOD70  
bFirst = false; dzKI?i)x  
read_nPos(); x9p,j  
} >01&3-r  
else w0q.cj@nd  
{ oGu-:X=`9  
nStartPos = new long[bean.getNSplitter()]; 4D0=3Vy  
nEndPos = new long[bean.getNSplitter()]; T:q!>"5  
} tF+m/}PM^  
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} xf_NHKZ)  
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public void run() _gEojuaN  
{ $Wjx$fD  
//获得文件长度 $rJgBN  
//分割文件 ?Yx2q_KZk  
//实例FileSplitterFetch CM6! 1 7  
//启动FileSplitterFetch线程 [{>3"XJ'  
//等待子线程返回 ;U3K@_  
try{ =?_:h`}  
if(bFirst) j`+{FCB7  
{ 9Wg;M#c2Y|  
nFileLength = getFileSize(); &Xc=PQ:I  
if(nFileLength == -1) IgRi(q^b-  
{ P4LiU2C  
System.err.println("File Length is not known!"); bM2x (E\
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} 96S$Y~G#&  
else if(nFileLength == -2) !K+hXQE1  
{ 1h#/8X  
System.err.println("File is not access!"); HA0F'k  
} lbGPy'h<rt  
else '-mzt~zGOY  
{ ?mF:L"i  
for(int i=0;i<nStartPos.length;i++) F&lH5  
{ @NL37C  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 1!yd(p=cL  
} 5A^8?,F@  
for(int i=0;i<nEndPos.length-1;i++) $inKI  
{ 1]Cdfj6@  
nEndPos = nStartPos[i+1]; z "z  
} Mf !S'\  
nEndPos[nEndPos.length-1] = nFileLength; \qTp#sF  
} ^y%8_r&  
} JDW/Mc1bh  
;mg.} fI  
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//启动子线程 aHb&+/HZ  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; IwOL1\'T4  
for(int i=0;i<nStartPos.length;i++) S(^YTb7  
{ &kn?=NW  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), BS?i!Bm7  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 72
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nStartPos,nEndPos,i); -8vGvI>  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Y;i
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fileSplitterFetch.start(); ] _W'-B  
} s Ytn'&$\  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 4>2\{0r  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); O9m sPb:  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", <WnIJum  
nEndPos = " + nFileLength); #DARZhU)  
// fileSplitterFetch[nPos.length-1].start(); m%UF{I,  
^6Zx-Mf\  
66sgs16k  
//等待子线程结束 feH&Ug4?G  
//int count = 0; g-,lY|a  
//是否结束while循环 WncHgz  
boolean breakWhile = false; i[MBO`FF  
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.Wr7*J[V.  
while(!bStop)  !VXy67  
{ +Z-{6C  
write_nPos(); }2\Hg
 
Utility.sleep(500); ,% 'r:@'  
breakWhile = true; .JTRFk{W  
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for(int i=0;i<nStartPos.length;i++) 4=`1C-v?q  
{ t=My=pG  
if(!fileSplitterFetch.bDownOver) V|F/ynJfA  
{ s&+`>  
breakWhile = false; q(WGvl^r  
break;  Lsai8 B  
} |eg8F$WU  
} xi
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if(breakWhile) G$)tp^%]  
break; PW iuM=E  
.:
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j?T>S]xOX  
//count++; BHS@whj  
//if(count>4) q2OF-.rE  
// siteStop(); }}u`*&,g  
} <%W&xk  
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System.err.println("文件下载结束！"); O_GHvLO=  
} >wL!`:c'"  
catch(Exception e){e.printStackTrace ();} B.smQt  
} MRZN4<}9  
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4E}Q<?UYSt  
//获得文件长度 b|G~0[g  
public long getFileSize() xls US'Eo  
{ nr8#;D  
int nFileLength = -1; ,aq>9\pi  
try{
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URL url = new URL(siteInfoBean.getSSiteURL()); b|may/xWH  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); %rf6>  
httpConnection.setRequestProperty("User-Agent","NetFox"); /VP #J<6L  
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int responseCode=httpConnection.getResponseCode(); 6i~<,;Cn  
if(responseCode>=400) UUM:*X  
{ "pcr-
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processErrorCode(responseCode); :8
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return -2; //-2 represent access is error &j/,8 Z*  
} /J Y6S  
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String sHeader; Os].
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for(int i=1;;i++) Xr4k]'Mg  
{ lPC{R k.\C  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); WX`wz>KK^  
//Utility.log(in.readLine()); R#?atL$(  
sHeader=httpConnection.getHeaderFieldKey(i); 8Fbt >-N<\  
if(sHeader!=null) G(o6/  
{ Fi7~JZZ  
if(sHeader.equals("Content-Length")) *lu*h&Y  
{ O*N:.|dUw  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 1W-kZ(e  
break; :/Z1$xS  
} 0B2f[A  
} "4T36b  
else <VQ@I  
break; &oJ[ *pQ  
} a@9W'/?igk  
} |mdf 
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catch(IOException e){e.printStackTrace ();} Xk:3w
,  
catch(Exception e){e.printStackTrace ();} q$s)(D  
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Utility.log(nFileLength); /xr75|-8  
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return nFileLength; .
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} ZEpu5`  
>* F#ZZv}p  
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//保存下载信息（文件指针位置） bP|-GCKM8  
private void write_nPos() \<y|[   
{ -]YsiE?r  
try{ pe).  
output = new DataOutputStream(new FileOutputStream(tmpFile)); _j{)%%?r  
output.writeInt(nStartPos.length); `r}a:w-  
for(int i=0;i<nStartPos.length;i++) Y(ClG*6 ++  
{ *_Ih@f H  
// output.writeLong(nPos); 74(bo\  
output.writeLong(fileSplitterFetch.nStartPos); qC=ZH#  
output.writeLong(fileSplitterFetch.nEndPos); z,@R jaX  
} Dr(;A>?qG  
output.close(); Ra^c5hP:.E  
} ycEp,V;[Z  
catch(IOException e){e.printStackTrace ();} hh.`Yu L  
catch(Exception e){e.printStackTrace ();} LW/> %  
} ]n'.}"8Kn  
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//读取保存的下载信息（文件指针位置） ?i!d00X  
private void read_nPos() >>;He7  
{ >m=
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try{ JuRWR0@`  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); An,TunX  
int nCount = input.readInt(); w*(1qUF#%  
nStartPos = new long[nCount]; ,w
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nEndPos = new long[nCount]; Ly1t'{"7  
for(int i=0;i<nStartPos.length;i++) bI
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{ M?n}{0E4  
nStartPos = input.readLong(); =NPo<^Lae  
nEndPos = input.readLong(); /nt%VLms%  
} !HW?/-\,O  
input.close(); O-~cj7 0\  
} MRK3Cey}%  
catch(IOException e){e.printStackTrace ();} g(S4i%\  
catch(Exception e){e.printStackTrace ();} 1p SEr6  
}  ZLf(m35  
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private void processErrorCode(int nErrorCode) z_y@4B6>}  
{ &##JZ  
System.err.println("Error Code : " + nErrorCode); Z^KWYe'w  
} YPw=iF]  
nA=E|$1  
v
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//停止文件下载 9om}j
  
public void siteStop() 9IacZ  
{ /de~+I5AB~  
bStop = true;  %Rm
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for(int i=0;i<nStartPos.length;i++) hs
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fileSplitterFetch.splitterStop(); UVsF !0  
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} FuFICF7+C  
} Rp}Sm,w(  
//负责部分文件的抓取 Q[aBxy (  
**FileSplitterFetch.java H^$7=  
*/ 5<oV>|*@{  
package NetFox; Ik=bgEF  
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import java.io.*; Z[\nyj  
import java.net.*; ),-MrL8c%  
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public class FileSplitterFetch extends Thread { 8Urj;KkD  
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String sURL; //File URL UGA``;f  
long nStartPos; //File Snippet Start Position i/,IG+4vI  
long nEndPos; //File Snippet End Position 2rS`ViicD  
int nThreadID; //Thread's ID 'W~6-c9y  
boolean bDownOver = false; //Downing is over <2^ F'bQV  
boolean bStop = false; //Stop identical x!?$y_t  
FileAccessI fileAccessI = null; //File Access interface zogl2e+  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 4L
&Rs;  
{ o&?:pE  
this.sURL = sURL; |W|RX3D  
this.nStartPos = nStart; <VT|R~  
this.nEndPos = nEnd; okbW. ~  
nThreadID = id; ( D
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fileAccessI = new FileAccessI(sName,nStartPos);//定位 Qf}}/k|)k  
} TM,Fab &  
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public void run() ):5H,B+Vr&  
{ zf[KZ\6H  
while(nStartPos < nEndPos && !bStop) n55s7wzM  
{ LJ*W&y(2>Q  
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*p^*>~i9)  
try{ K|rG&#1J  
URL url = new URL(sURL); 7x(z  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 0?'v|5}  
httpConnection.setRequestProperty("User-Agent","NetFox"); /f!ze|  
String sProperty = "bytes="+nStartPos+"-"; R]TS5b-  
httpConnection.setRequestProperty("RANGE",sProperty); ?!n0N\|i]  
Utility.log(sProperty); NH8\&#}nAK  
9?+?V}o  
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InputStream input = httpConnection.getInputStream(); H+VjY MvK  
//logResponseHead(httpConnection); z?C&,mv
 
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byte[] b = new byte[1024]; wf,w%n  
int nRead; ()(/9t  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) VCvFCyAz  
{ ~J|B  
nStartPos += fileAccessI.write(b,0,nRead); jd}-&DN  
//if(nThreadID == 1) XchVsA  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); SbD B[O%  
} Z$Vd8U;  
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Utility.log("Thread " + nThreadID + " is over!"); W7q!F  
bDownOver = true;  dm{/  
//nPos = fileAccessI.write (b,0,nRead); RjGJfN{  
} &MP +  
catch(Exception e){e.printStackTrace ();} zdN(r<m9"  
} V7,;N@FL  
} Uk0 0lPG.U  
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//打印回应的头信息 B3@\Ua)  
public void logResponseHead(HttpURLConnection con) zd{\XW  
{ C+aL8_(R  
for(int i=1;;i++) s.>;(RiJd  
{ =_vW7-H  
String header=con.getHeaderFieldKey(i); s)7sgP  
if(header!=null) 3;wOA4ur  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); bA(-7l?  
Utility.log(header+" : "+con.getHeaderField(header)); @[hD;xO  
else 4So ,m0v  
break; je5GZFQw  
} ^:^8M4:  
} :<R"
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]+@I]\S4  
$/$ 5{<  
public void splitterStop() ^<+V[=X  
{ YiTVy/  
bStop = true; -X,[NI3  
} T9-2"M=|<  
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} Qjd<%!]+\  
/fC8jdp&  
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/* v|;}}ol  
**FileAccess.java g I@I.=y  
*//文件访问(定位，写) 1\%2@NR  
package NetFox; Kb*X2#;*  
import java.io.*; A%%Vyz  
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public class FileAccessI implements Serializable{ 
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Q
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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 05Y4=7,!  
RandomAccessFile oSavedFile; |&AZ95v   
long nPos; 9"b =W@  
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public FileAccessI() throws IOException TX$4x~:  
{ :a'[4w  
this("",0); Ae_:Kc6  
} L3'$"L.|u  
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3 cF4xUIZ  
public FileAccessI(String sName,long nPos) throws IOException 6~!l7HqO  
{ +$\/HO  
oSavedFile = new RandomAccessFile(sName,"rw"); m"RSDM!  
this.nPos = nPos; !6l}s$1i|  
oSavedFile.seek(nPos); P,={ C6*  
} ja+PVf  
]r(s02  
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public synchronized int write(byte[] b,int nStart,int nLen) L_Lhmtm}m  
{ @agxu-Y  
int n = -1; KU*XRZu)  
try{ )5/,B-+O"  
oSavedFile.write(b,nStart,nLen); UA(&_-C\  
n = nLen; F`RPXY`ux  
} %SN"<O!  
catch(IOException e) tqwAS)v=  
{ b+e9Pi*\  
e.printStackTrace (); USJk *  
} ((mR'A|`  
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?[c{pb,|  
return n; F$te5 `a  
}
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} g&?{^4t]  
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/* \<W/Z.}/  
**SiteInfoBean.java F6gU9=F1<  
*/ 'QC'*Hl  
package NetFox; H_d^Xk QZ  
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public class SiteInfoBean { )h`8</#m{  
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private String sSiteURL; //Site's URL OI
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private String sFilePath; //Saved File's Path L^xh5{  
private String sFileName; //Saved File's Name w,eW?b  
private int nSplitter; //Count of Splited Downloading File Y>SpV_H%  
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s%i \z }/  
public SiteInfoBean() 7&3
  
{//nSplitter的缺省值为5 H_>9'(  
//default value of nSplitter is 5 <KBS ;t="1  
this("","","",5);
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} xzz0uk5  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) @|EWif|  
{ sr-tZ^d5S?  
sSiteURL= sURL; jhH&}d9  
sFilePath = sPath; ) m(!lDz3  
sFileName = sName; Wg\MaZ6Di  
this.nSplitter = nSpiltter; BI+x6S>d  
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m"GgaH3,  
} C_S2a0?  
3wN{k\ns  
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public String getSSiteURL() @Io@1[kj  
{ '9@AhiNV  
return sSiteURL; #T++5G  
} K8RV=3MBLD  
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=B0AG9Fz  
public void setSSiteURL(String value) U88gJ[$  
{ !nL>Ly  
sSiteURL = value; O'h f8w  
} dF$&fo%  
[,sm]/Xlc  
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public String getSFilePath() ti!kJ"q  
{ G.]'pn  
return sFilePath; mv>-XJ+  
} qW`DCZu  
$ D.*r*c6  
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public void setSFilePath(String value) ^j7>Ul,  
{ *JF7
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sFilePath = value; `Gh J)WA<  
} pU1miA '  
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m ;yIFO  
public String getSFileName() 3v~[kVhoG  
{ Q'rgh+6  
return sFileName; lP*p7Y '  
} Vp&"[rC_z  
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N"s"^}M\  
public void setSFileName(String value) mC} b>\  
{ wizLA0W  
sFileName = value; eI98J"h%?  
} ~DP5Qi  
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public int getNSplitter() F0tcVdv  
{ OV|n
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return nSplitter; s*R UYx  
} XbIxGL  
U#:N/ts*(  
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public void setNSplitter(int nCount) >dXB)yl  
{ (L`IL e*  
nSplitter = nCount; UJ><B"  
} o:`^1  
} %E[ $np>  
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|

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/* ce:wF#Qs
 
**Utility.java >Se-5QtLcf  
*/ Kx02 2rgDU  
package NetFox; /0b7"Kr  
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public class Utility { 
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}=A+W2D  
public Utility() eOahr
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{ 1BSn#Dnj  
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} 6Ev+!!znu  
5xQ5)B4k  
//线程睡眠 WO$8j2!~#  
public static void sleep(int nSecond) F`>qg2wO  
{ ?}HZJ@:lB  
try{ `
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Thread.sleep(nSecond); b^A7R{G7  
} 2 SU  
catch(Exception e) \+Y5b}  
{ ^UBzX;|p  
e.printStackTrace (); ~:*V'/2k  
} a:s$[+'Y  
} @6*eS+t\  
3zv0Nwb,  
//日志 {LT2^gy=  
public static void log(String sMsg) f#-\*  
{ h-fm)1S_  
System.err.println(sMsg); qe/5'dw  
} u qA!#E
 
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/ 2MhP=
,  
public static void log(int sMsg) WBR# Ux  
{ "n{JH9sA:  
System.err.println(sMsg); l!": s:/'  
} bl{W{?QI  
} !Ej?9LHo  
[LrO"9q(  
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/* jQ8 T  
**TestMethod.java y5XFJj  
*/ ^4xl4nbx  
package NetFox; U+aiH U9  
&{q<  
t"OP*  
public class TestMethod { $ago  
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,+X:#$  
public TestMethod() J!">L+Zcx  
{ ///xx/weblogic60b2_win.exe
j
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try{ Kd\d>&b  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); JW"`i   
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Q_dMuoI  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 93
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fileFetch.start(); V."cmtf  
} /N,\st  
catch(Exception e){e.printStackTrace ();} [fY7|  
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} 7>F[7_  
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public static void main(String[] args) "~KTLf  
{ J&B5Ll  
new TestMethod(); I9xkqj  
} FI~=A/:  
} +G+1B6S  
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