http断点续传简单实现（java)

/* v0)I rO  
**SiteFileFetch.java !t/I j~o  
*/ R{"Kh2q_  
package NetFox; }t}y  
import java.io.*; {2Jo|z  
import java.net.*; NO5\|.,Z  
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public class SiteFileFetch extends Thread { <7-:flQz~  

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SiteInfoBean siteInfoBean = null; //文件信息Bean o?zA'5q  
long[] nStartPos; //开始位置 ]E/^(T-O  
long[] nEndPos; //结束位置 M4[(.8iE  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 !Au'WJfE  
long nFileLength; //文件长度 5Fa.X|R~  
boolean bFirst = true; //是否第一次取文件 wq$+m(  
boolean bStop = false; //停止标志 
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File tmpFile; //文件下载的临时信息 @I_
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DataOutputStream output; //输出到文件的输出流 (JV [7u -  
1.
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 4mYJi#e6x  
public SiteFileFetch(SiteInfoBean bean) throws IOException !R@v\Eu  
{ Z!HQ|')N5  
siteInfoBean = bean; &c[.&L,w4  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath()));
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tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); /j%(Z/RM  
if(tmpFile.exists ()) QX`Qnk|Y  
{ Cn6<I{`\  
bFirst = false; 2z*EamF  
read_nPos(); u*n%cXY;J/  
} 4WspPHj  
else 3i
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{ n:dnBwY  
nStartPos = new long[bean.getNSplitter()]; f%#q}vK-  
nEndPos = new long[bean.getNSplitter()]; 'P'f`;'_DC  
} ":
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} 7LotN6H  
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public void run() ]*/%5ZOI&
 
{ sKu/VAh x  
//获得文件长度 +g.lLb*#  
//分割文件 *
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//实例FileSplitterFetch eHX;*~e6)  
//启动FileSplitterFetch线程 <rQ+ErDA  
//等待子线程返回 opaRk.p  
try{ 7&O0  
if(bFirst) T~D2rt\  
{ uv#."_Va  
nFileLength = getFileSize(); )\O;Rt(  
if(nFileLength == -1) kg/<<RO  
{ 8cKP_Ec  
System.err.println("File Length is not known!"); n?a?U:  
} >^!)G^B  
else if(nFileLength == -2) 1@}s:  
{ *'l|ws  
System.err.println("File is not access!"); f3;.+hJ])  
} bz'#YM  
else *@+E82D  
{ Z@1vJH6IbA  
for(int i=0;i<nStartPos.length;i++) PS:"mP7n  
{ ",,W1]"%  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 6B8gMO  
} &m5FYm\  
for(int i=0;i<nEndPos.length-1;i++) ^}Wk  
{ yiO/0nMp  
nEndPos = nStartPos[i+1]; +H**VdM6s  
} %3kS;AaA  
nEndPos[nEndPos.length-1] = nFileLength; Y[~Dj@Q<  
} zm~sq_=^  
} %mFZ!(  
<>71;%e;'  
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//启动子线程 fUKi@*^ZUa  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ^.gBHZ  
for(int i=0;i<nStartPos.length;i++) UlD]!5NO  
{  I?R?rW
 
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), bnzIDsw!Q  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), !,Uzt1K:  
nStartPos,nEndPos,i); v\ <4y P  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); O[<YYL0  
fileSplitterFetch.start(); Neb")  
} [sc4ULS &  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), {kOTQG?y  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 8M6wc394  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", &P:2`\'  
nEndPos = " + nFileLength); :jHDeF.A  
// fileSplitterFetch[nPos.length-1].start(); 5fDp"-  
'UFPQ  
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//等待子线程结束 NK!#K>AO  
//int count = 0; /6@$^paB  
//是否结束while循环 H"b}lf  
boolean breakWhile = false; crlCN  
pPH"6   
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while(!bStop) 0\KDa$'1k  
{ &6O0h0Vy  
write_nPos(); \Y$@$)   
Utility.sleep(500); D:=Q)Uh0I  
breakWhile = true; ^
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for(int i=0;i<nStartPos.length;i++) ., =\/ C<  
{ c2~oPUj  
if(!fileSplitterFetch.bDownOver) [kKg?I$D@B  
{ H[[#h=r0f  
breakWhile = false; LXq0hI  
break; +Ua.\1"6  
} q]rqFP0C  
} e13' dCG  
if(breakWhile) 78h!D[6  
break; VlFhfOR6
t  
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//count++; =2OLyZDI  
//if(count>4) )u>/:  
// siteStop(); La8D%N  
} YgR}y+q^6  
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System.err.println("文件下载结束！"); |y DaFv  
} EHH+)mlo  
catch(Exception e){e.printStackTrace ();} E5Zxp3N  
} P;V5f8r?  
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9?I?;l{  
//获得文件长度 k`=&m"&#  
public long getFileSize() bZCNW$C3l  
{ ZRn!z`.0  
int nFileLength = -1; PL*1-t?#  
try{ i:n1Di1~E  
URL url = new URL(siteInfoBean.getSSiteURL()); I*EHZctH  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); |'!9mvt=  
httpConnection.setRequestProperty("User-Agent","NetFox"); M d.^r5r  
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int responseCode=httpConnection.getResponseCode(); q vGP$g  
if(responseCode>=400) =v6qr~  
{ JLh{>_Rr  
processErrorCode(responseCode);
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return -2; //-2 represent access is error V*%Lc9<d  
} r68d\N`.  
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String sHeader; 4;)aGN{e  
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for(int i=1;;i++) 3Q2z+`x'  
{ TQ69O +  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); i/j eb*d0  
//Utility.log(in.readLine()); Jk_}y  
sHeader=httpConnection.getHeaderFieldKey(i); .2x`Fj;o1  
if(sHeader!=null) v@Bk)Z  
{ +P|Z1a -jB  
if(sHeader.equals("Content-Length")) 7CSd}@71\  
{ ( P\oLr9  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); &w{: qBa  
break; =q<t,UP8  
} ^ Q  
} #sb@)Q  
else LDYk\[81  
break; x.ucsb  
} w'&QNm>  
} Q+zy\T  
catch(IOException e){e.printStackTrace ();} VskdC?yIp  
catch(Exception e){e.printStackTrace ();} ~!#2s'  
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Utility.log(nFileLength); Wq"^{  
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return nFileLength; *x@.$=NF"  
} XpT+xv1`;  
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//保存下载信息（文件指针位置） ~vw$Rnotz  
private void write_nPos() [zr2\(  
{ N(Xg#m  
try{ kA{eT  
output = new DataOutputStream(new FileOutputStream(tmpFile)); E=RX^ 3+}  
output.writeInt(nStartPos.length); KCi0v  
for(int i=0;i<nStartPos.length;i++) gmdA1$c  
{ >L,Pw1Y0W[  
// output.writeLong(nPos); VdF<#(
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output.writeLong(fileSplitterFetch.nStartPos); 25/M2u?  
output.writeLong(fileSplitterFetch.nEndPos); ?;ovh nY)  
} 4rH:`494  
output.close(); F+285JK  
} m?`?T   
catch(IOException e){e.printStackTrace ();} bI+ TFOP  
catch(Exception e){e.printStackTrace ();} 68nBc~iAm  
} Q=#@g  
*9|*21  
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//读取保存的下载信息（文件指针位置） FGu#Pa  
private void read_nPos() L /V;;  
{ xAu&O\V  
try{ Zz^!QlF  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); `c/mmS  
int nCount = input.readInt(); >m4HCs>  
nStartPos = new long[nCount]; mM\jU5P:^  
nEndPos = new long[nCount]; 57`9{.HB  
for(int i=0;i<nStartPos.length;i++) ;\rKkH"K8n  
{ {:ZsUnzm  
nStartPos = input.readLong(); FSA"U9 w<  
nEndPos = input.readLong(); Bw4 _hlm  
} K%(DRkj)  
input.close(); w?"s6L3  
}
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catch(IOException e){e.printStackTrace ();} /tu\q  
catch(Exception e){e.printStackTrace ();} {]3Rk  
} ~s-"u *>  
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private void processErrorCode(int nErrorCode) *IV_evgM7  
{ DRmN+2I  
System.err.println("Error Code : " + nErrorCode); N\W
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} ,&0iFUwN_  
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//停止文件下载 $-"V 2  
public void siteStop() F.@U X
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{ %617f=(E?!  
bStop = true; X$9 "dL  
for(int i=0;i<nStartPos.length;i++) +=g9T`YbE  
fileSplitterFetch.splitterStop(); (VB-5&b  
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} o 76QQ+hP  
} OE5JA8/H  
//负责部分文件的抓取 [hXnw'Im/  
**FileSplitterFetch.java )=6o,  
*/ #({ 9M  
package NetFox; Gu5%Pou  
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import java.io.*; mFW/xZwR,5  
import java.net.*; Z Ne(sg~G  
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public class FileSplitterFetch extends Thread { P= nu&$;  
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String sURL; //File URL ;
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long nStartPos; //File Snippet Start Position #/2W RN1L  
long nEndPos; //File Snippet End Position N!YjMx)P  
int nThreadID; //Thread's ID 0mYKzJi  
boolean bDownOver = false; //Downing is over
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boolean bStop = false; //Stop identical O+*<^*YyD  
FileAccessI fileAccessI = null; //File Access interface t7qzAr  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ^UiSezcI  
{ i[rXs/]  
this.sURL = sURL; O cJ(i#Q~<  
this.nStartPos = nStart; hH*/[|z  
this.nEndPos = nEnd; O&ZVu>`g  
nThreadID = id; bbAJ5EqL  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 7B8.;0X$W  
} xa$p,_W:'  
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public void run() aOK,Mm:iO  
{ NI33lp$V  
while(nStartPos < nEndPos && !bStop) 026|u|R  
{ ebmU~6v k  
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try{ .Q$/\E  
URL url = new URL(sURL); +u]L#].;  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 3tAX4DnYrq  
httpConnection.setRequestProperty("User-Agent","NetFox"); mCQn '{)  
String sProperty = "bytes="+nStartPos+"-"; XWNDpL`j5  
httpConnection.setRequestProperty("RANGE",sProperty); {Bm7'%i  
Utility.log(sProperty); @l^BW*BCo  
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InputStream input = httpConnection.getInputStream(); H6/C7  
//logResponseHead(httpConnection); KQv97#n1  
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byte[] b = new byte[1024]; 'H.,S_v1x  
int nRead; TOvpv@?-  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ._5"FUg  
{ "[M k5tM  
nStartPos += fileAccessI.write(b,0,nRead); l7M![Ur  
//if(nThreadID == 1) gW(7jFl  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); u&\QZW?  
} 3I%F,-r  
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Utility.log("Thread " + nThreadID + " is over!"); 9]^ CD
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bDownOver = true; R}VEq gq  
//nPos = fileAccessI.write (b,0,nRead); ZclZD{%8J  
} QGI_aU  
catch(Exception e){e.printStackTrace ();} DS]C`aM9  
} 4kqgZtg.  
} dB%q`7O  
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//打印回应的头信息 \yNe5  
public void logResponseHead(HttpURLConnection con) oGa8#>  
{ 1`z^Xk8vt  
for(int i=1;;i++) A(dWAe,  
{ $b=4_UroS  
String header=con.getHeaderFieldKey(i); :SD^?.W\iT  
if(header!=null) t3b64J[A{  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); k~+(X|!5w  
Utility.log(header+" : "+con.getHeaderField(header)); @& vtY._  
else s)<^YASg  
break; yQ{xRtNO  
} V(A p|I:G  
} >nA6w$  
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public void splitterStop() E"{2R>mU~  
{ aHzS>  
bStop = true; j4hi
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} /Q8glLnM  
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} ',<Bo{  
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/* ?h*Ngb
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**FileAccess.java "\]NOA*  
*//文件访问(定位，写) OB{d^e}  
package NetFox; 1aQR9zg%  
import java.io.*; f4Yn=D=_  
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public class FileAccessI implements Serializable{ G?t<4MTv  
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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 A_mVe\(*M  
RandomAccessFile oSavedFile; $aFCe}3b<  
long nPos; >#Obhs|S{C  
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public FileAccessI() throws IOException {+&qC\YF  
{ fA k]]PU  
this("",0); 4%(\y"T  
} y]veqa  
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public FileAccessI(String sName,long nPos) throws IOException c9c_7g'q-  
{ "Y> #=>8  
oSavedFile = new RandomAccessFile(sName,"rw"); (pl|RmmDz  
this.nPos = nPos; dV( "g],  
oSavedFile.seek(nPos); l|z0aF;z  
} 7t@r}rC,K  
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public synchronized int write(byte[] b,int nStart,int nLen) ]hPu  
{ b85r=tm   
int n = -1; zB?} {@  
try{ p:GB"e9>H  
oSavedFile.write(b,nStart,nLen); 8-2e4^ g(  
n = nLen; yyj?hR@rZ  
} w4m)lQM  
catch(IOException e) <h*r  
{ R.FC3<TTv  
e.printStackTrace (); - DO  
} / X #4  
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return n; kma)DW  
} 0Q]ZS  
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} ?OYK'p.  
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/s'7[bSv  
/* )H'SU_YU  
**SiteInfoBean.java %]2hxTV  
*/ mip2=7M|C  
package NetFox; $ e<108)]  
8$+mST'4N  
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public class SiteInfoBean { c,K)*HB  
h2b,(  
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private String sSiteURL; //Site's URL 8%@![$q<g  
private String sFilePath; //Saved File's Path ?nLlZpZ2v  
private String sFileName; //Saved File's Name C
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private int nSplitter; //Count of Splited Downloading File W7_j;7'  
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_{]\} =@  
public SiteInfoBean() x'4q`xDa  
{//nSplitter的缺省值为5 .d JX,^  
//default value of nSplitter is 5 GV+K] KDI  
this("","","",5); ;yvx-  
} rF3QmR?l  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) J|uxn<E<>  
{ va>u1S<lO  
sSiteURL= sURL; BrHw02G  
sFilePath = sPath; V>$A\AWw  
sFileName = sName; ?F^$4
:  
this.nSplitter = nSpiltter; }f~:>N#  
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%
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} wNk 0F7Ck  
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public String getSSiteURL() _+OnH!G0  
{ qM$4c7'4P6  
return sSiteURL; zeHf(N  
} un)YK  
3>~W_c9@  
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public void setSSiteURL(String value) Rz #&v  
{ d7f{2  
sSiteURL = value; 4R(H@p%+r2  
} 1I=>
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^5MPK@)c,/  
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public String getSFilePath() UgVLHwkvk  
{ @26gP:Um  
return sFilePath; TZl^M h[a  
} V1P]mUs{1  
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public void setSFilePath(String value) \Nvu[P  
{ }MCh$  
sFilePath = value; D(' w<9.  
} i40'U?eG~6  
+E7Os|m  
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public String getSFileName() **D3.-0u&  
{ NMM$ m!zg  
return sFileName; K&\ q6bU  
}  W0&x0  
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public void setSFileName(String value) XK";-7TZt  
{ =o!1}'1}}  
sFileName = value; Q[wTV3d  
} xA&RMu&  
#80[q3  
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public int getNSplitter() 5}+&Em":  
{ yMd<<:Ap  
return nSplitter; o#^(mGj_.  
} 9tMaOm  
^%qe&Pe2  
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public void setNSplitter(int nCount) Fuz'!  
{ +n)_\@aQ  
nSplitter = nCount; !jySID?q  
} ZNKopA(=|%  
} r*r3QsO  
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/* P,eP>55'K  
**Utility.java 4eRV?tE9  
*/ 2m*g,J?ql  
package NetFox; (\I9eBm  
pef)c,U$  
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public class Utility { <73dXTZ0  
\C&[BQ\  
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public Utility() AW R  
{ 5Y3L  
4ZX6=-u^  
_=\J:r|Y:  
}  EL$"/ptE  
\Zgc [F  
//线程睡眠 WXj iKW(  
public static void sleep(int nSecond) \{@n>Mh  
{ Gkr]8J  
try{ `xq/<U;i  
Thread.sleep(nSecond); *B3 4  
} ,u<oAI`  
catch(Exception e) gB)Cmw*  
{ L%CBz]`  
e.printStackTrace (); ,bGYixIfYZ  
} 8k0f&Cak=  
} QF74'  
S=@bb$4-T  
//日志 7;i [  
public static void log(String sMsg) dc+U#]tS  
{ nn?h;KzB  
System.err.println(sMsg); y!kU0  
} %`# HGji)  
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public static void log(int sMsg) i[#XYX'\  
{ _no;B_m~  
System.err.println(sMsg); 1zP)~p3a  
} Gpb<,v_3  
} g.wDg  
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L>>RboR}  
/* 0zHMtC1,  
**TestMethod.java |lG7/\A  
*/ J/(^Z?/~P!  
package NetFox; w~%Rxdh?8W  
n([9U0!gu  
)s~szmJoVD  
public class TestMethod { /n3Qcht  
u==`]\_@  
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public TestMethod() ; "K"S[  
{ ///xx/weblogic60b2_win.exe >3qfo2K0  
try{ csd~)a nb  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); GD-cP5$  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ?lPyapA]  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 8JFvz(SK>  
fileFetch.start(); 4/?@%  
} hR+\,P#G[  
catch(Exception e){e.printStackTrace ();} wV\.NQtS  
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} 5kx-s6`!  
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public static void main(String[] args) ]I[\Io1  
{ H2JKQm_  
new TestMethod(); C)?tf[!_6  
} 'o]kOp@q  
} 8n"L4jb(:  
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