http断点续传简单实现（java)

/* v0~'`*|&  
**SiteFileFetch.java
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*/ D{%l 4og  
package NetFox; HM'P<<  
import java.io.*; /h)_Q;35S;  
import java.net.*; FiN^}Kh  
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public class SiteFileFetch extends Thread { 2WKYf0t  
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SiteInfoBean siteInfoBean = null; //文件信息Bean )qgcz<p?W  
long[] nStartPos; //开始位置 X\?PnD`,  
long[] nEndPos; //结束位置 hJuR,NP  
FileSplitterFetch[] fileSplitterFetch; //子线程对象
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long nFileLength; //文件长度 HnDz4eD  
boolean bFirst = true; //是否第一次取文件 oCl $ 0x  
boolean bStop = false; //停止标志 J$9`[^pV  
File tmpFile; //文件下载的临时信息 PS" ,  
DataOutputStream output; //输出到文件的输出流 Ro&s\T+d  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） v[3QI7E3  
public SiteFileFetch(SiteInfoBean bean) throws IOException zz4TJ('  
{ pN-l82]'  
siteInfoBean = bean; m :6.  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); J(k\Pz*  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); X/=*o;":  
if(tmpFile.exists ()) n^HKf^]  
{ M Y2=lT  
bFirst = false; a>3#z2#  
read_nPos(); O
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} U Bo[iZ|%  
else F\!Va  
{ -r.Qy(}p  
nStartPos = new long[bean.getNSplitter()]; .7h:/d Y:  
nEndPos = new long[bean.getNSplitter()]; 7Ya4>*B  
} Ya%-/u  
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} R2]2#3`  
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public void run() k<bA\5K  
{ ?3f-"K_r  
//获得文件长度 L7\rx
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//分割文件 'U9l   
//实例FileSplitterFetch M_<? <>|  
//启动FileSplitterFetch线程 X?2ub/Nr#Y  
//等待子线程返回 D*!UB5<>/t  
try{ I}?+>cf  
if(bFirst) 5_|Sm=  
{ XZ|%9#6  
nFileLength = getFileSize(); G*oqhep  
if(nFileLength == -1) (%bqeI!ob  
{ )D_\~n/5  
System.err.println("File Length is not known!"); 5:oteNc
3  
} X9|={ng)g#  
else if(nFileLength == -2) +,"O#`sy<  
{ S:.Vt&+NJ  
System.err.println("File is not access!"); <)f1skJsP  
} bgi B*`z  
else 6RA4@bIG  
{ 
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for(int i=0;i<nStartPos.length;i++) y4jJ&  
{ RM5$O+"  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); IB'gY0*  
} |%V-|\GJ~j  
for(int i=0;i<nEndPos.length-1;i++) g>@T5&1q*  
{ O]|T !  
nEndPos = nStartPos[i+1]; l\Q--

 
} W8@o7svrh  
nEndPos[nEndPos.length-1] = nFileLength; M%U1?^
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} .B9i`)0  
} | Ns-l (l  
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//启动子线程 C0RnBu  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; KOYU'hw  
for(int i=0;i<nStartPos.length;i++) p3Ey[kURp  
{ >Y3ZK{b  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), &8w MGahp  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), j'2:z#  
nStartPos,nEndPos,i); s-S#qGZ  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); bhqV2y*'  
fileSplitterFetch.start(); a 8(mU%  
} +NM`y=@@  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), >EVY,  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); pA~eGar_J  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", +\Zr\fOe|%  
nEndPos = " + nFileLength); 4s <|8  
// fileSplitterFetch[nPos.length-1].start(); "DpgX8lG_  
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//等待子线程结束 gwAZ2w  
//int count = 0; [M;B 9-2$  
//是否结束while循环 K6..N\7  
boolean breakWhile = false; eG\|E3Cb9  
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while(!bStop) 9i8 ~  
{ 54^2=bp  
write_nPos(); OG!+p}yD]  
Utility.sleep(500); W%&[gDp  
breakWhile = true; Z(~v{c %<  
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for(int i=0;i<nStartPos.length;i++) M%aA1!@/  
{ E U# M.  
if(!fileSplitterFetch.bDownOver) hFiJHV  
{ v\#1&</qd^  
breakWhile = false; mO?yrM *  
break; :m{;<LRV  
} Bh%Yu*.f  
} ah8xiABa  
if(breakWhile) d i;Fj  
break; HW"';M%  
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d[t+iBP;)  
//count++; xGBp+j1H  
//if(count>4) vgyv~Px]AW  
// siteStop(); A4|L;z/A[h  
} H[;\[3  
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System.err.println("文件下载结束！"); kJfMTfl,  
} Jh6 z5xUV  
catch(Exception e){e.printStackTrace ();} 1>"Yw|F-|3  
} aj\ zc I  
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//获得文件长度 B=,j$uH  
public long getFileSize() .!><qVg  
{ IT5a/;J  
int nFileLength = -1; =D}]
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try{ (&=gM  
URL url = new URL(siteInfoBean.getSSiteURL()); =0" Zse,  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 6M)4v{F  
httpConnection.setRequestProperty("User-Agent","NetFox"); ]?/7iM  
:jP4GCxU|  
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int responseCode=httpConnection.getResponseCode(); D'UYHc{  
if(responseCode>=400) ;bh[TmQTJ  
{ uJg|  
processErrorCode(responseCode); [\|p~Qb)s  
return -2; //-2 represent access is error P&2/J%@zG  
} (vXes.|+t  
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String sHeader; 4w)aAXK  
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for(int i=1;;i++) nN|1cJ'.Fk  
{ `{ 6K~(  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); jeLC)lQ*  
//Utility.log(in.readLine()); {YT@$K]w,  
sHeader=httpConnection.getHeaderFieldKey(i); !92zC._  
if(sHeader!=null) c1CUG1i  
{ mY& HK)  
if(sHeader.equals("Content-Length")) [$+N"4  
{ &nXa/XIZ_  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); CEMe2~  
break; Ga9^+.j  
} 7L"Pe'Hw  
} +bC=yR  
else r'/H3  
break; x]X!nx6G  
} {r.yoI4e  
} 9[7Gxmf  
catch(IOException e){e.printStackTrace ();} So^;5tG  
catch(Exception e){e.printStackTrace ();} lA1l  
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Utility.log(nFileLength); /E|Ac&Qk  
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return nFileLength; /#]4lF
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} b+DBz}L4  
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//保存下载信息（文件指针位置） d#OE) ,`  
private void write_nPos() d_r1}+ao  
{ ,FP<# 0F*a  
try{ ,vE)/{:d  
output = new DataOutputStream(new FileOutputStream(tmpFile)); <T0+-]i  
output.writeInt(nStartPos.length); !U?Z<z
h  
for(int i=0;i<nStartPos.length;i++) OY?x'h  
{ ]!=,8d
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// output.writeLong(nPos); D$W
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output.writeLong(fileSplitterFetch.nStartPos); tc2e)WZP  
output.writeLong(fileSplitterFetch.nEndPos); N*CcJp{Q  
} lgL|[ik`  
output.close(); n\x@~ SzrX  
} JF%_8Ye5  
catch(IOException e){e.printStackTrace ();} M6mJ'Q482  
catch(Exception e){e.printStackTrace ();} ZY Ci&l  
} p~!UE/V  
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//读取保存的下载信息（文件指针位置） G$HXc$OY  
private void read_nPos() /GQN34RD  
{ JXa5snh{h  
try{ Lao
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DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); S7fX1y[  
int nCount = input.readInt(); ]=EYju@  
nStartPos = new long[nCount]; @UG%B7  
nEndPos = new long[nCount]; +LEU|#  
for(int i=0;i<nStartPos.length;i++) @|hn@!YK  
{ f(r=S Xa*  
nStartPos = input.readLong(); )t#v55M  
nEndPos = input.readLong(); ja_.{Zv  
} [$bK%W{f  
input.close(); UW?(-_8  
} =Co[pt  
catch(IOException e){e.printStackTrace ();} q0a8=o"|  
catch(Exception e){e.printStackTrace ();} s;[OR  
} 0K*|B.O  
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private void processErrorCode(int nErrorCode) )>X C_ R  
{ r`8>@2sW1  
System.err.println("Error Code : " + nErrorCode); /eI]!a  
} ET[vJnReC  
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//停止文件下载 N
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public void siteStop() *Mg. *N  
{ [Jjb<6[o  
bStop = true; ;94e   
for(int i=0;i<nStartPos.length;i++) 3tZC&!x?  
fileSplitterFetch.splitterStop(); !eH9LRp  
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} 9jC>OZ0s  
} MS~|F^g  
//负责部分文件的抓取 %9qG|A,cA  
**FileSplitterFetch.java F6$QEiDu@  
*/ J_H=GHMp}  
package NetFox; e~+VN4D&b>  
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import java.io.*; E7K(I ?  
import java.net.*; NGYUZ\m  
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public class FileSplitterFetch extends Thread { 6*({ZE  
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String sURL; //File URL }0 BKKU+  
long nStartPos; //File Snippet Start Position :{YOJD
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long nEndPos; //File Snippet End Position <Z -d5D>  
int nThreadID; //Thread's ID 1l(_SD;90t  
boolean bDownOver = false; //Downing is over u*aFWl]=  
boolean bStop = false; //Stop identical  >>n
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FileAccessI fileAccessI = null; //File Access interface e7cqm*Qi  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 4 )U,A~!  
{ 0bt"U=x4  
this.sURL = sURL; Y\sSW
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this.nStartPos = nStart; Z^ e?V7q  
this.nEndPos = nEnd; %v_w"2x;  
nThreadID = id;
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fileAccessI = new FileAccessI(sName,nStartPos);//定位 JQp::,g
 
} ,vnHEY&  
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public void run() xMb)4cw}  
{ 64hl0'67y  
while(nStartPos < nEndPos && !bStop) 9~En;e  
{ !}TZmwf'  
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try{ aIA
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URL url = new URL(sURL); eVVm"96Q.;  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); xXJl Qbs  
httpConnection.setRequestProperty("User-Agent","NetFox"); 9MmAoLm  
String sProperty = "bytes="+nStartPos+"-"; *&m{)cTs  
httpConnection.setRequestProperty("RANGE",sProperty); '|9fDzW"]  
Utility.log(sProperty); `h:$3a:5  
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InputStream input = httpConnection.getInputStream(); nVp*u9]  
//logResponseHead(httpConnection); NFEF{|}BM  
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byte[] b = new byte[1024]; RJz$$,RU  
int nRead; h5x_Vjj  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) #:Tb(R   
{ 
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nStartPos += fileAccessI.write(b,0,nRead); #})OnM^],  
//if(nThreadID == 1) Mu>GgQSZ  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); w,<nH:~  
} xux
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Utility.log("Thread " + nThreadID + " is over!"); <ah!!  
bDownOver = true; .sO.Y<-fl  
//nPos = fileAccessI.write (b,0,nRead); %B,>6 `[  
} h^tU*"   
catch(Exception e){e.printStackTrace ();} xw)$).yc  
} 
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} Yb~[XS |p  
/hojm6MM  
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//打印回应的头信息 +~E;x1&'  
public void logResponseHead(HttpURLConnection con) |fJpX5W-l  
{ *G<K@k  
for(int i=1;;i++) S:*.,zC  
{ ?dJ[?<aG  
String header=con.getHeaderFieldKey(i); 6zJ<27  
if(header!=null) h7}D//~p  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); <vP{U  
Utility.log(header+" : "+con.getHeaderField(header)); g.&n X/  
else %LH~Im=  
break; vw;GbQH(  
} xcF:moL  
} VdVUYp  
*kliI]BF]  
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public void splitterStop()  <|Pw*L$  
{ x9,X0JO  
bStop = true; lf<?k  
} &L88e\ c+  
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} KfSI6 Y_  
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7_HJ|QB  
/* Y5 BWg  
**FileAccess.java O0"u-UX{  
*//文件访问(定位，写) : J3_g<@  
package NetFox; GW]b[l
 
import java.io.*;
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public class FileAccessI implements Serializable{ G,VTFM6  

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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 <"93  
RandomAccessFile oSavedFile; \c"{V-#o\  
long nPos; %Km^_JM  
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public FileAccessI() throws IOException yX^/Oc@j  
{ Rh[%UNl  
this("",0); @Kx@ 2#~b  
} w:|BQ,  
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public FileAccessI(String sName,long nPos) throws IOException Rl. YF+YH  
{ p~n62(  
oSavedFile = new RandomAccessFile(sName,"rw"); B4hT(;
k  
this.nPos = nPos; [VD)DO5  
oSavedFile.seek(nPos); 4x`.nql  
} h
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*J ]2"~_.  
public synchronized int write(byte[] b,int nStart,int nLen) Ju0W  
{ F8c^M</  
int n = -1; yX-h|Cr"  
try{ s+EJXoxw  
oSavedFile.write(b,nStart,nLen); H pZD^h?L  
n = nLen; MJ=(rp=YU9  
} _iJ8*v8A  
catch(IOException e) jD`p;#~8  
{ 9S.J%*F7  
e.printStackTrace (); ;tBc&LJ?  
} WOv m%sX  
{^Y0kvnd  
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return n; $KmhG1*s  
} 
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} '@{'T LMCi  
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/* c]u^0X?&  
**SiteInfoBean.java "JH /ODm  
*/ [m}58?0~x  
package NetFox; da'7* &/  
QR.]?t;1  
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public class SiteInfoBean { \Q CH.~]  
<b5J"i&m  
4v=NmO}  
private String sSiteURL; //Site's URL \Y>!vh X  
private String sFilePath; //Saved File's Path 3I" <\M4x  
private String sFileName; //Saved File's Name yY3Mv/R  
private int nSplitter; //Count of Splited Downloading File 6r|BiHP  
=GP~h*5es  
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public SiteInfoBean() OdZLJt?g  
{//nSplitter的缺省值为5 g[#4`Q<.  
//default value of nSplitter is 5 Zx1I&K\Cd  
this("","","",5); (_9cL,v  
} nVO|*Bnf)  
@CxXkR  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ^Hdru]A$2  
{ UC u4S >  
sSiteURL= sURL; /+11`B0
9  
sFilePath = sPath; KMhEU**  
sFileName = sName; YgeU>I|v  
this.nSplitter = nSpiltter; h rksPK"s2  
A.5N<$l  
.y)Y20=o!  
} NV[_XXTv7  
>h[ {_+  
0cpI2  
public String getSSiteURL() |?kZfr&9q  
{ "1-|ahW  
return sSiteURL; ThvVLK  
} 3RW3<n  
tW=,o&C=  
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public void setSSiteURL(String value) RfZZqeU  
{ G;'=#c ^  
sSiteURL = value; kY$vPHZpN  
} &ND8^lR=Y;  
p5`d@y\hj  
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public String getSFilePath() dV:vM9+x  
{ /IkSgKJiz\  
return sFilePath; %.zcE@7*  
} ^<}>]F_  
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public void setSFilePath(String value) bSKe@4C  
{ ]xYm@%>6  
sFilePath = value; X-Q;4M-CJ  
} 1>$}N?u:T  
`4&a"`&$  
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public String getSFileName() lwhVP$q}  
{ Z,? T`[4B  
return sFileName; --32kuF&(  
} w|;kL{(W  
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public void setSFileName(String value) p?#c
n   
{ fFBD5q(n  
sFileName = value; c'678!r9 P  
} Za&.sg3RG  
W8/8V,  
S]P80|!|  
public int getNSplitter() 0D\b;ju<  
{ =N+Ou5D  
return nSplitter; H=f'nm]dQ  
} 5z$>M3  
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public void setNSplitter(int nCount) 7n_'2qY  
{ ZgXn8O[a  
nSplitter = nCount; T9N&Nh7 3  
} Ao%;!(\I%  
} `2j \(N,  
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/* e/h2E dY  
**Utility.java ?;//%c8,.  
*/ TDMyZ!d  
package NetFox; WC?}a^
8  
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public class Utility { 9
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{
  
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public Utility() ^J([w~&  
{ uAWmg8  
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} z_jTR[dY  
@\!9dK-W  
//线程睡眠 icX$<lD  
public static void sleep(int nSecond) 6L2Si4OGjG  
{ vfh0aW-O  
try{ K]b_JDEk  
Thread.sleep(nSecond); azUEp8`|  
} NWGSUUa  
catch(Exception e) /f:)I.FUm  
{ [~ Wiy3n  
e.printStackTrace (); `F#<qZSR  
} R]-$]koQO  
} NW$C1(oT  
OZw<YR  
//日志 7\q_^  
public static void log(String sMsg) 05|,-S  
{ wc-ll&0Z  
System.err.println(sMsg); qlUw;{;p  
} 7jb{E+DrG  
BBub'  
Qe~2'Hw#9  
public static void log(int sMsg) Qoj}]jve  
{ 8Jz/'  
System.err.println(sMsg); a-`OE"  
} is3nLm(  
} %PsDS  
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/* t*fG;YOg  
**TestMethod.java +3c!.] o;  
*/ x bG'![OX  
package NetFox; wGqQR)a  
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a=55bEn  
public class TestMethod { '.@'^80iQ  
U#B,Q6~  
n&. bs7N2  
public TestMethod() T4W"!4[  
{ ///xx/weblogic60b2_win.exe jU#/yM"Y  
try{ Z66b>.<8  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); kXj%thDx  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); IZm_/  
SiteFileFetch fileFetch = new SiteFileFetch(bean); iwHy!Vi-5  
fileFetch.start(); _HT
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} 0I.9m[<Fc  
catch(Exception e){e.printStackTrace ();} I6]|dA3G  
g5EdW=Dt,  
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} b}G4eXkuj  
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public static void main(String[] args) ;w(]z  
{ <JA`e+Bi  
new TestMethod(); BO5g
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} @-z#vJ5Qe{  
} QK5y%bTSA  
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