http断点续传简单实现（java)

/* "&/:"~r  
**SiteFileFetch.java BcaMeb-Z  
*/ t1p}
  
package NetFox; )&di c6r  
import java.io.*; LO@.aJpp  
import java.net.*; J<x?bIetj  
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public class SiteFileFetch extends Thread { $Gb] K{e  
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SiteInfoBean siteInfoBean = null; //文件信息Bean X1U7$/t  
long[] nStartPos; //开始位置 pq[RH-{  
long[] nEndPos; //结束位置 R?Y#>K  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 <apsG7(7
 
long nFileLength; //文件长度 d;&'uiS  
boolean bFirst = true; //是否第一次取文件 U#G[#sd> K  
boolean bStop = false; //停止标志 V-a/%
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File tmpFile; //文件下载的临时信息 =W)Fa6P3j(  
DataOutputStream output; //输出到文件的输出流 +7?p&-r)x  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） S/-[OA>N  
public SiteFileFetch(SiteInfoBean bean) throws IOException {\22C `9t  
{ _3<J!$]&p  
siteInfoBean = bean; E>Ukxi1  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); m`C(y$8fU  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); QytqO{B^  
if(tmpFile.exists ()) TF 6_4t6  
{ q@;WXHO0  
bFirst = false; `we2zT  
read_nPos(); lZCvH1&"  
} \{J gjd  
else aNb=gjLpt  
{ pH.wCD:
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nStartPos = new long[bean.getNSplitter()]; c38RE,4U  
nEndPos = new long[bean.getNSplitter()]; =zXpeo&|m  
} +]
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} qgrRH
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public void run() NylN-X7[#  
{ !zLd,`  
//获得文件长度 _Hi;Y  
//分割文件 "L.)ML  
//实例FileSplitterFetch 9'3%%o  
//启动FileSplitterFetch线程 QU16X  
//等待子线程返回 )hK5_]"lmj  
try{ t3u"2B7o
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if(bFirst) ,eOOV@3C  
{ :gDIGBK,  
nFileLength = getFileSize(); r<V]MwO=  
if(nFileLength == -1) Da1BxbDeI  
{ *MW)APw=  
System.err.println("File Length is not known!"); >x@]wsj  
} _
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else if(nFileLength == -2) 1i#uKKwE  
{ hXM8`iFW5  
System.err.println("File is not access!"); cyA|6Ltg%  
} JV(eHuw  
else 4>>{}c!nf  
{ &#v^y3r  
for(int i=0;i<nStartPos.length;i++) PXm{GLXRS;  
{ ]B=B@UO@.  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 67%eAS  
} lxj_(Uo  
for(int i=0;i<nEndPos.length-1;i++) 5+rYk|*D+k  
{ J|_&3@r  
nEndPos = nStartPos[i+1]; A?|KA<&m#u  
} &>0=v  
nEndPos[nEndPos.length-1] = nFileLength; LW?] ~|  
} %75|+((fC  
} 5p"n g8nR  
 dKDtj:  
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//启动子线程 cy*Td7)/  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; h'^7xDw  
for(int i=0;i<nStartPos.length;i++) XV1#/@H;  
{ vi@a87w>  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), w_@NT}  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), (ZQ{%-i?qR  
nStartPos,nEndPos,i); O^G/(  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); kLMg|48fdI  
fileSplitterFetch.start(); dG.s8r*?M  
} '@2pOq  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), cKh
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); !FipKX  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 8U0y86q>)E  
nEndPos = " + nFileLength); "p.MJxH  
// fileSplitterFetch[nPos.length-1].start(); ncb
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//等待子线程结束 !tCw)cou  
//int count = 0; :N\*;>  
//是否结束while循环 '[I_Iu#,  
boolean breakWhile = false; h|yv*1/|  
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while(!bStop) yU\&\fD>j  
{ + htTrHjt  
write_nPos(); );@Dr!H  
Utility.sleep(500); )s,L:{<  
breakWhile = true; qW6a|s0}  
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for(int i=0;i<nStartPos.length;i++) $6XSW  
{ rK)So#'  
if(!fileSplitterFetch.bDownOver) wg^#S  
{ vvv~n
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breakWhile = false; j;<Yje&Wz  
break; apF!@O^}y  
} cn v4!c0  
} *I`Sc|A  
if(breakWhile) UAnq|NJO  
break; 699z@>$}
 
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//count++; 
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//if(count>4) <>A:
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// siteStop(); xYc)iH
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} oR5hMu;j+  
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System.err.println("文件下载结束！"); Y]{<IF:  
} =2s5>Oz+  
catch(Exception e){e.printStackTrace ();} ~7Kqc\/H&I  
} /[VafR!  
Id *Gs>4U  
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//获得文件长度 ro6|N?'  
public long getFileSize() ] ^tor
 
{ 5UVQ48aT  
int nFileLength = -1; sD1L 
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try{ ^uW](2  
URL url = new URL(siteInfoBean.getSSiteURL()); _K)B  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 9.qIhg  
httpConnection.setRequestProperty("User-Agent","NetFox"); ;tf1#6{  
k sJz44  
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int responseCode=httpConnection.getResponseCode(); Cmm"K[>Rx  
if(responseCode>=400) T3[\;ib}  
{ wp-5B= #:{  
processErrorCode(responseCode); 8JAA?0L"'  
return -2; //-2 represent access is error HelC_%#^  
} =5b5d  
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String sHeader; KwN o/x| v  
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for(int i=1;;i++) }Jk.c~P)  
{ l$z[Vh^UU<  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); p>Ju)o  
//Utility.log(in.readLine()); Cnd*%CPZ  
sHeader=httpConnection.getHeaderFieldKey(i); }
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if(sHeader!=null) >MUwT$szs  
{ qBpv[m  
if(sHeader.equals("Content-Length")) "6~pTHT  
{ ]cc4+}L~  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); NZe3 m  
break; HW|c -\t
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} 2}'qu)  
} |H2{%!  
else n4 KiC!*i0  
break; /SY40;k:  
} LXVm0IOFF  
} :M`|*~V~$  
catch(IOException e){e.printStackTrace ();} K)]7e?:Wu  
catch(Exception e){e.printStackTrace ();} ;8JJ#ED  
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Utility.log(nFileLength); Xf:CGR8_  
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return nFileLength; -fj;9('YJ  
} ~4U[p 50  
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//JF$o=)D  
//保存下载信息（文件指针位置） F] +t/
 
private void write_nPos() ?f1%)]>   
{ 76c4~IG#  
try{ r4gkSwy  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ,YSQog  
output.writeInt(nStartPos.length); Fw+JhIVP  
for(int i=0;i<nStartPos.length;i++) @!Il!+^3  
{ 9|v  
// output.writeLong(nPos); fm;1Iu#  
output.writeLong(fileSplitterFetch.nStartPos); BtBo%t&  
output.writeLong(fileSplitterFetch.nEndPos); 2 L%d,Ta>  
} C@buewk  
output.close(); j5R= K*y  
} FMwT4]y  
catch(IOException e){e.printStackTrace ();} |^S[Gr w  
catch(Exception e){e.printStackTrace ();} )3.udx  
} !.+iA=K{  
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//读取保存的下载信息（文件指针位置） X-3L4@T:?  
private void read_nPos() 1|;WaO1Q  
{ $B~a*zZ7  
try{ Aw4Qm2Kf  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); #Q^mdv?  
int nCount = input.readInt(); c500:OSB  
nStartPos = new long[nCount]; _( w4\]  
nEndPos = new long[nCount]; y@~.b^?_u  
for(int i=0;i<nStartPos.length;i++) f4/!iiS}r  
{ \Wt&z,  
nStartPos = input.readLong(); k|BY 7C  
nEndPos = input.readLong(); U>e@m?  
} l2gI2Cioa  
input.close(); m]Z+u e  
} csRba;Z[  
catch(IOException e){e.printStackTrace ();} 1Lqs>*  
catch(Exception e){e.printStackTrace ();} g|"z'_  
} ?TMo6SU  
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private void processErrorCode(int nErrorCode) !h?N)9e  
{ y|.wL=;  
System.err.println("Error Code : " + nErrorCode); AW+4Vm_!l  
} mrFMdpaHl%  
hYi-F.Qtq  
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//停止文件下载 Jfo|/JQ  
public void siteStop() 3`^]#Dh  
{ [DGq{(
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bStop = true; jd]MC*%  
for(int i=0;i<nStartPos.length;i++) tDy1Gh/c  
fileSplitterFetch.splitterStop(); x~Se-#$  
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} ai#EFo+#  
} eFsku8$<  
//负责部分文件的抓取 ut3jIZ1]  
**FileSplitterFetch.java 0AR4/5.  
*/ SkvKzV.R;  
package NetFox; (ter+rTv  
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import java.io.*; g=i|D(".  
import java.net.*; xs.[]>nQN  
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public class FileSplitterFetch extends Thread { YH<@->Ip  
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String sURL; //File URL %}'sFum`  
long nStartPos; //File Snippet Start Position <6v7_  
long nEndPos; //File Snippet End Position `f6Qd2\  
int nThreadID; //Thread's ID | @di<d@  
boolean bDownOver = false; //Downing is over yv$MQ~]  
boolean bStop = false; //Stop identical @o;m!CYB  
FileAccessI fileAccessI = null; //File Access interface qn+mlduU  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Bu6t3  
{ oL VtP  
this.sURL = sURL; *}[@*  
this.nStartPos = nStart; /Zm@.%.  
this.nEndPos = nEnd; 1$xt=*.u|  
nThreadID = id; XZKOBq B]  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ZQ~?  
} 'JkK0a2D  
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public void run() tH W"eag  
{ |/p^e  
while(nStartPos < nEndPos && !bStop) n`^</0  
{ ?d_<S0j-)  
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try{ vW]BOzK  
URL url = new URL(sURL); JBU qZ  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); _a.Q@A4'  
httpConnection.setRequestProperty("User-Agent","NetFox"); #p_ ~L4iW  
String sProperty = "bytes="+nStartPos+"-"; E)Hp.  
httpConnection.setRequestProperty("RANGE",sProperty); /CX<k gz@  
Utility.log(sProperty); Jwa2Y0  
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InputStream input = httpConnection.getInputStream(); Ay56@_d2  
//logResponseHead(httpConnection); TF{ xFb)  
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byte[] b = new byte[1024]; $ Q2|{*  
int nRead; -><?q t  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ?[T&y ,ln  
{ _N*4 3O`  
nStartPos += fileAccessI.write(b,0,nRead); nR ,j1IUF  
//if(nThreadID == 1) VqYe0-^=P  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Y
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} xpSMbX{e  
7v=Nh  

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Utility.log("Thread " + nThreadID + " is over!"); *[ A%tj%  
bDownOver = true; YE0s5bB6  
//nPos = fileAccessI.write (b,0,nRead); f+F /`P%  
} yfaXScbE  
catch(Exception e){e.printStackTrace ();} KU$.m3A>  
} O(!wDnhc  
} }l_) d  
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?)JW}3<.  
//打印回应的头信息 4}=]QQoE  
public void logResponseHead(HttpURLConnection con) kOkgsQQ  
{ 1Z*-@%RX  
for(int i=1;;i++) WE
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{ p-zLi!  
String header=con.getHeaderFieldKey(i); }rOO[,?Y  
if(header!=null) /Nxy?g|,  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); #t{?WkO[  
Utility.log(header+" : "+con.getHeaderField(header)); ]Nm_<%lT  
else uTn(fs)D  
break; Bz]64/  
} ?hmj0i;XC  
} =f{r+'[;^  
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public void splitterStop() \O\onvEa  
{ D'
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bStop = true; U3p=H^MB.  
} qzmY]N+w|  
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} ~|fd=E%  
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/* &9TG&~(+  
**FileAccess.java |} .Y&1@U  
*//文件访问(定位，写) '{Iv?gh"  
package NetFox; L?0dZY-"  
import java.io.*; ~ ]o .Mv a  
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public class FileAccessI implements Serializable{ ~` #t?1SP  
iB[%5i-  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 \
6nWt6M  
RandomAccessFile oSavedFile;  #*?5  
long nPos; =V%s^  
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public FileAccessI() throws IOException EPdR-dC^wE  
{ [o\O^d  
this("",0); \ $z.x-U  
} kS3wa3bT  
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public FileAccessI(String sName,long nPos) throws IOException JdFMSmZ@  
{ El]Rrku  
oSavedFile = new RandomAccessFile(sName,"rw"); wD}[XE?S  
this.nPos = nPos; [2.pZB  
oSavedFile.seek(nPos); I
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} `'.u$IBW  
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public synchronized int write(byte[] b,int nStart,int nLen) H2|&  
{ q"`1cFD  
int n = -1; 8H3|^J  
try{ ^|-xmUC  
oSavedFile.write(b,nStart,nLen); ki=-0G*]  
n = nLen; q-X)tH_+w@  
} :C_\.p
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catch(IOException e) 8%>  Ls  
{ %Mz(G-I.\  
e.printStackTrace (); E(>RmPP=7  
} 7bCTR2e\@w  
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return n; a]BnHLx  
}  lrU}_`  
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} T/dchWG  
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/* j'#W)dp(  
**SiteInfoBean.java k2_ "  
*/  #/MUiV  
package NetFox; Dwe_ytjpc  
w}K<,5I>  
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public class SiteInfoBean { g\OPidY  
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private String sSiteURL; //Site's URL l;b5v]~  
private String sFilePath; //Saved File's Path K%1'zSAyK  
private String sFileName; //Saved File's Name 7-nwfp&|$  
private int nSplitter; //Count of Splited Downloading File +8]}'6m  
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public SiteInfoBean() yOxJx7uD  
{//nSplitter的缺省值为5 ?r"m*fY
%  
//default value of nSplitter is 5 K%Vl:2#F  
this("","","",5);
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} "|gNNmr  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) &|LZ%W0Fb  
{ Q Bc\=}  
sSiteURL= sURL; wBTnI>l9[  
sFilePath = sPath; P`v%< 9~  
sFileName = sName; q%]0%S?  
this.nSplitter = nSpiltter; _1VtVfiZ{  
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#6[FGM  
} SuMK=^>%  
,ic.b @u1  
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public String getSSiteURL() =P!SN]nFeP  
{ MW=2GhD=  
return sSiteURL; n9B1NM5 \  
} N1jj\.nB  
3b 
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public void setSSiteURL(String value) Nc()$Nl8  
{ 1C6H\;  
sSiteURL = value; n{J<7I e"*  
} B8NOPbT  
_'JKPD[  
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public String getSFilePath() mWZoo/xtT  
{ k%?wNk>  
return sFilePath; RcitW;{|Kg  
} ^n"ve2  
`PnB<rf:*1  
-
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public void setSFilePath(String value) i|0H {q  
{ }A'QXtI/G  
sFilePath = value; g!(j.xe  
} ZC'(^liAp  
$/ew'h9q  
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public String getSFileName() 5K|1Y#X  
{ yf(VwU, x  
return sFileName; #lRkp.e  
} j4$XAq~W  
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y)X1!3~(  
public void setSFileName(String value) %Ak"d+OH4  
{ );$_|]#  
sFileName = value; l  3bo  
} (dvCejc^p  
}A;J-7g6  
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public int getNSplitter() s|.V:%9e  
{ d#cw`h<c~  
return nSplitter; 1nhC! jDD  
} `j{5$X  
^noKk6Aaa  
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public void setNSplitter(int nCount) #)QR^ss)iw  
{ 3Z;`n,g  
nSplitter = nCount; %GQPiWu  
} ,rx?Ig}kz  
} J=|PZ2"  
. S4Xw2MS  
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/* Z_Ffiw(p  
**Utility.java PMC5qQ%x  
*/ s ki'I  
package NetFox; EUevR/S  
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public class Utility { *o <S{  
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public Utility() 9}LcJ  
{ E0]B=-  
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1\K%^<QY  
} }xXUCU<  
mDZ/Kp{  
//线程睡眠 .BP@1K  
public static void sleep(int nSecond) 5nC#<EE  
{ r&6X|2@  
try{ k'Is]=3  
Thread.sleep(nSecond); R"%zmA@o=  
}  1$nlRQi  
catch(Exception e) V
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{ EY'kIVk  
e.printStackTrace (); eU/o I}A  
} &/o4R:i  
} t&m8 V$Q  
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//日志 ((OQs.  
public static void log(String sMsg) 5qZe
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{ IkW8$>  
System.err.println(sMsg); (SMnYh4  
} R.nAD{>h*  
PX!$
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^\o3V<  
public static void log(int sMsg) SLI(;, s  
{ R#QOG}  
System.err.println(sMsg); ]k0Pe;<  
} b2rlj6d  
} m/M=.\]  
S)`%clN}J  
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/* e'"2yA8dh"  
**TestMethod.java ~1xfE C/  
*/ 2H\}N^;f  
package NetFox; lQ5d.}O&  
sn>2dRW{  
tNk.|}  
public class TestMethod { YCMXF#1  
9x4%M&<Z9a  
hD)'bd  
public TestMethod() }.ZT?p\  
{ ///xx/weblogic60b2_win.exe ML:Zm~A1U  
try{ R%%Uw %`  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); X%>nvp  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); u4eA++eT  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 3rdrNc  
fileFetch.start(); ab-z 7g  
}  ,>C`|  
catch(Exception e){e.printStackTrace ();} :}B=Bk/q  
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@XJzM]*w&  
} 5I`_SOa!  
6y0CEly>3#  
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public static void main(String[] args) UR{OrNg*  
{ JKjVrx> @  
new TestMethod(); `T#Jiq E  
} &eA!h  
} $*\GZ$y>  
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