http断点续传简单实现（java)

/* {&+M.Xn  
**SiteFileFetch.java 7<su8*?  
*/ XP)^81i|  
package NetFox; 9)wYSz'  
import java.io.*; sSU|N;"Y  
import java.net.*; wG49|!l6T  
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public class SiteFileFetch extends Thread { ].s;Yxz  
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SiteInfoBean siteInfoBean = null; //文件信息Bean =mXC,<]  
long[] nStartPos; //开始位置 $wAR cS  
long[] nEndPos; //结束位置 Ba[,9l[  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 W
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long nFileLength; //文件长度 - VJx)g  
boolean bFirst = true; //是否第一次取文件 loIb}8  
boolean bStop = false; //停止标志 a <C?- g|  
File tmpFile; //文件下载的临时信息 JOuyEPy  
DataOutputStream output; //输出到文件的输出流 opH!sa@U  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 3RaW\cWzg  
public SiteFileFetch(SiteInfoBean bean) throws IOException _^W;J/He  
{ ;qaPK2a8  
siteInfoBean = bean; :(]fC~G~  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); pq`uB  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ,NQ!d4~D  
if(tmpFile.exists ()) F`7v  
{ g `s|]VNt  
bFirst = false; 0h A:=r  
read_nPos(); >Lo\?X~  
} >e {1e  
else bL xZ5C7t  
{ aVu!Qk=Z/  
nStartPos = new long[bean.getNSplitter()]; SE\?8cs]-  
nEndPos = new long[bean.getNSplitter()]; d3:GmB .  
} ,!_6X9N-h  
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} c*rH^Nz  
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public void run() @dv8 F "v  
{ ?JZ$M  
//获得文件长度 >eA@s}_8  
//分割文件 e@vtJaSu  
//实例FileSplitterFetch ]mMJ6n  
//启动FileSplitterFetch线程 42
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//等待子线程返回 #_.JkY  
try{ l~"T>=jq3  
if(bFirst) SAdT#0J  
{ 2 `>a(  
nFileLength = getFileSize(); BP9#}{kE  
if(nFileLength == -1) %rb$tKk  
{ 4`
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System.err.println("File Length is not known!"); )I&.6l!#  
} ~)f^y!PMQ  
else if(nFileLength == -2) ./ {79  
{ Kn:Ml4[;  
System.err.println("File is not access!"); #DgHF*GG+>  
} e%cTFwX?n  
else 3SIqod;%  
{ +4-T_m/W/  
for(int i=0;i<nStartPos.length;i++) U,P>P+\@  
{ Ms|c"?se  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Qn8xe,  
} I]C
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for(int i=0;i<nEndPos.length-1;i++) XSC=qg$  
{ Z$/76  
nEndPos = nStartPos[i+1]; 'TS_Am?o  
} iv>MIdIm  
nEndPos[nEndPos.length-1] = nFileLength; 3A`Gx#  
}
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} ^m%#1Zd  
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//启动子线程 ?Ujg.xo\  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; gl+d0<Rzw  
for(int i=0;i<nStartPos.length;i++) ZjmQ  
{ d 5yEgc;z  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), mxqD'^n#  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), {|u"I@M*O  
nStartPos,nEndPos,i); @#4-4.6I<x  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 2yK">xYY@  
fileSplitterFetch.start(); ]^C 8Oh<  
} 1_TuA(  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), qf(mJlU  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); cuN]}=D  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", tQ{/9bN?P  
nEndPos = " + nFileLength); ;+wB!/k,  
// fileSplitterFetch[nPos.length-1].start(); nmU1xv_  
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//等待子线程结束 H<Sf0>OA  
//int count = 0; %[$HX'Y  
//是否结束while循环 7,SQz6]  
boolean breakWhile = false; Kd-
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while(!bStop) N; }$!sNIm  
{ |@AXW   
write_nPos(); Y_CVDKdcY  
Utility.sleep(500); V^,gpTyv*  
breakWhile = true; _4N.]jr5  
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for(int i=0;i<nStartPos.length;i++) S-Y{Vi"2  
{ P{9:XSa%  
if(!fileSplitterFetch.bDownOver) #r9+thyC  
{ <(KCiM=E$  
breakWhile = false; -iiX!@  
break; Y$L` G  
} 1w=.vj<d8  
} 7z$Z=cs  
if(breakWhile) 2{h2]F  
break; 8b?nr;@  
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//count++; U"7o;q  
//if(count>4) 4fKvB@O@.  
// siteStop(); c6[m'cy  
} >B{qPrmI  
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System.err.println("文件下载结束！"); ]W?cy  
} z}Cjk6z@  
catch(Exception e){e.printStackTrace ();} @4;'>yr(  
} lBfthLBa  
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//获得文件长度 H7'42J@  
public long getFileSize() \$_02:#  
{ "zcAYg^U  
int nFileLength = -1; $jMA(e`Ye0  
try{ U:*rlA@_.  
URL url = new URL(siteInfoBean.getSSiteURL()); <~dfp  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); QG*hQh  
httpConnection.setRequestProperty("User-Agent","NetFox"); aA4RC0'  
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int responseCode=httpConnection.getResponseCode(); lWc[Q1  
if(responseCode>=400) nDvfb*\  
{ sc]#T)xG  
processErrorCode(responseCode); qefp3&ls  
return -2; //-2 represent access is error QKP #wR  
} =wX;OK|U(^  
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String sHeader; q(qm3OxYo  
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for(int i=1;;i++) }p?,J8=-  
{ l?)>"^  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Wq3PN^  
//Utility.log(in.readLine()); KRxJ2  
sHeader=httpConnection.getHeaderFieldKey(i); G|jHic!  
if(sHeader!=null) >l 0aME@-0  
{ (/uN+  
if(sHeader.equals("Content-Length")) H}r]j\  
{ h>bjG  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 2;sTSGDG  
break; d[?RL&hJO  
} 4vL\t uoz  
} O + aK#eF  
else qVh?%c1.Y  
break; MX]#|hEeQ  
} Lz1KDXr`)+  
} "=Z=SJ1D  
catch(IOException e){e.printStackTrace ();} h~Ir=JV  
catch(Exception e){e.printStackTrace ();} |$/#,Dv7  
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Utility.log(nFileLength); oqvu8"  
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return nFileLength; UhJS=YvT  
} lai@,_<GV  
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//保存下载信息（文件指针位置） 0dwD ?GG2  
private void write_nPos() ^JxVs 7  
{ 6/cm TT$i  
try{ w(bvs&`{uC  
output = new DataOutputStream(new FileOutputStream(tmpFile)); (tA[]ne2  
output.writeInt(nStartPos.length); jkl dr@t  
for(int i=0;i<nStartPos.length;i++) _8$xsj4_  
{ A@~9r9Uf  
// output.writeLong(nPos); pzRVX8  
output.writeLong(fileSplitterFetch.nStartPos); jy~hLEt7  
output.writeLong(fileSplitterFetch.nEndPos); NCg("n,jx  
} 2XyyU}.$  
output.close(); >0SG]er@  
} |34k;l]E  
catch(IOException e){e.printStackTrace ();} 2.nT k  
catch(Exception e){e.printStackTrace ();} |m\7/&@<  
} " :e <a?  
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//读取保存的下载信息（文件指针位置） .?#Q(eLj  
private void read_nPos() \0lQ1FrY  
{ N#-%b"(  
try{ -5e8m4*
 
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); L2Cb/!z`c  
int nCount = input.readInt(); !]R>D{""  
nStartPos = new long[nCount]; B0RVtbK  
nEndPos = new long[nCount]; v"2A?  
for(int i=0;i<nStartPos.length;i++) MX*4d{l  
{ lre(]oBXA  
nStartPos = input.readLong(); \=RV?mI3?  
nEndPos = input.readLong(); IV&5a]j  
} :{eYm|2-  
input.close(); !}|'1HIC  
} [GCaRk>b,  
catch(IOException e){e.printStackTrace ();} D+AkV|  
catch(Exception e){e.printStackTrace ();} !|9@f$Jv  
} i*l=xW;bM  
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private void processErrorCode(int nErrorCode) "$5cKbJ  
{ QX?moW6UW  
System.err.println("Error Code : " + nErrorCode); r+Sv(KS4i^  
} ^VzhjKSu  
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//停止文件下载 DQObHB8L  
public void siteStop() = <A0;  
{ l^tRy_T:-  
bStop = true; yEB#*}K?  
for(int i=0;i<nStartPos.length;i++) \Dr( /n  
fileSplitterFetch.splitterStop(); ,W'P8C  
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} B!x6N"  
} BQ,749^S  
//负责部分文件的抓取  f^}n#  
**FileSplitterFetch.java 4<<eqxI$|  
*/ Wf?[GO  
package NetFox; ?W dY{;&  
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import java.io.*; ,y0 &E8Z  
import java.net.*; kxrYA|x  
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public class FileSplitterFetch extends Thread { (uHyWEHt  
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String sURL; //File URL 3 %BI+1&T_  
long nStartPos; //File Snippet Start Position F1}d@^K 7d  
long nEndPos; //File Snippet End Position o]]tH  
int nThreadID; //Thread's ID Rc93Fb-Zp  
boolean bDownOver = false; //Downing is over u>] )q7s  
boolean bStop = false; //Stop identical oG hMO  
FileAccessI fileAccessI = null; //File Access interface s,mt%^
x[  
/ZL6gRRA|  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 3:w_49~:~  
{ |A
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this.sURL = sURL; )yz)Fw|&  
this.nStartPos = nStart; Bs '=YK$  
this.nEndPos = nEnd; kTzO4s?  
nThreadID = id; [@pumH
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fileAccessI = new FileAccessI(sName,nStartPos);//定位 Z"l].\= F  
} 0}` -<(  
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public void run() i$.!8AV6  
{ ]l=CiG4!M  
while(nStartPos < nEndPos && !bStop) r0OP !u  
{ D\-DsT.H  
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try{ I~HA ad,k  
URL url = new URL(sURL); Yp3y%n  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Te3 ?
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httpConnection.setRequestProperty("User-Agent","NetFox"); y(a>Y! dgU  
String sProperty = "bytes="+nStartPos+"-"; all2?neK  
httpConnection.setRequestProperty("RANGE",sProperty); ([SJ6ff]&  
Utility.log(sProperty); ,1t|
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InputStream input = httpConnection.getInputStream(); ;i [;%  
//logResponseHead(httpConnection); oFzmH!&ED  
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byte[] b = new byte[1024]; .Y!dO@$:  
int nRead; ]R^xO;g'  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 1;,<UHF8N  
{ N3)n**  
nStartPos += fileAccessI.write(b,0,nRead); d|gfp:Z`a  
//if(nThreadID == 1) H4wDF:n0H  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ~XXNzz]?  
} JCB3 BZg7&  
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Utility.log("Thread " + nThreadID + " is over!"); =RM]/O9  
bDownOver = true; IQ$6}.  
//nPos = fileAccessI.write (b,0,nRead); |~v2~   
} ]XX>h~0  
catch(Exception e){e.printStackTrace ();} {EV
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} ^mut-@ N9  
} !F Zg' 9  
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//打印回应的头信息 fU.z_T[@  
public void logResponseHead(HttpURLConnection con) (_N(K`4#W  
{ U9\w)D|+eE  
for(int i=1;;i++) DdeKZ)8  
{ ]Ee$ulJ02  
String header=con.getHeaderFieldKey(i); eT2Tg5Etc  
if(header!=null) #op0|:/

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//responseHeaders.put(header,httpConnection.getHeaderField(header)); .WBp!*4  
Utility.log(header+" : "+con.getHeaderField(header)); v@fy*T\3  
else cQ`0d3  
break; s?Gv/&  
} s=K?-O  
} CLuQ=-[
|  
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public void splitterStop() h>Z`&  
{ _0
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bStop = true; (7$BF~s:,  
} Nn?$}
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} ]1[:fQF7/L  
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/*
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**FileAccess.java n7/&NiHxv/  
*//文件访问(定位，写) nYBa+>3BDf  
package NetFox; ^nFP#J)_5  
import java.io.*; ?1LRR ;-x  
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public class FileAccessI implements Serializable{ 4#t-?5"  
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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 U?5G%o(q  
RandomAccessFile oSavedFile; :FmH=pI!=  
long nPos; m|OB_[9  
lO0}  
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public FileAccessI() throws IOException e:rbyzf#  
{ ]8'PLsS9<w  
this("",0); t4hc X[  
} $e uI  
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public FileAccessI(String sName,long nPos) throws IOException )NqRu+j  
{ z"Cyjmg"  
oSavedFile = new RandomAccessFile(sName,"rw");
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this.nPos = nPos; `'pAiu  
oSavedFile.seek(nPos); a#9pN?~  
} y(^\]-fE  
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public synchronized int write(byte[] b,int nStart,int nLen) G9GLRdP  
{ ekmWYQ ~  
int n = -1; u
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try{ :V_UJ3xf  
oSavedFile.write(b,nStart,nLen); F'B0\v=  
n = nLen; J`{o`>  
} n@q-f-2  
catch(IOException e) N8J(RR9O  
{ S a
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e.printStackTrace (); cz|?j  
} @*|T(068&  
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return n; 3Y&4yIx  
} =([4pG  
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} +!$`0v
  
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/* deTD|R  
**SiteInfoBean.java dT (i*E\j  
*/ ^r mQMjF  
package NetFox; <~
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public class SiteInfoBean { i` ay9J8N  
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private String sSiteURL; //Site's URL kJNwA8 7  
private String sFilePath; //Saved File's Path h@y>QhYU0  
private String sFileName; //Saved File's Name (Fq:G
) $  
private int nSplitter; //Count of Splited Downloading File 9b@yDq3hQ  
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public SiteInfoBean() t%<y^Wa=  
{//nSplitter的缺省值为5 >[~7fxjK-  
//default value of nSplitter is 5 dep"$pys>  
this("","","",5); j0(jXAc;UB  
} J(wFJg\/  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 1-&L-c.  
{ fc[_~I'  
sSiteURL= sURL; }6=)w@v  
sFilePath = sPath; A5%$<  
sFileName = sName; gFTlP  
this.nSplitter = nSpiltter; }d;6.~Gw  
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} NSH4 @x  
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public String getSSiteURL() U4yl{?  
{ =)gdxywoC  
return sSiteURL; KC9e{  
} ?)(-_N&T  
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public void setSSiteURL(String value) p(8@  
{ *c&|2EsZ  
sSiteURL = value; x}
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} ^H{YL
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public String getSFilePath() nAAv42j[  
{ fFWi 3.  
return sFilePath; Hrph>v  
} 6 .)Xeb"  
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public void setSFilePath(String value) B&0W P5OF  
{ %~gI+0HK  
sFilePath = value; 7mM
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} cO5zg<wF  
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ed  
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public String getSFileName() 22U`1AD3U  
{ S6a\KtVa  
return sFileName; (Cfb8\~  
} QCE7VV1Rw  
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public void setSFileName(String value) X{OWDy  
{ !2Z"Lm  
sFileName = value; i1-%#YYF(  
} /]MelW  
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public int getNSplitter() Gn_DIFa  
{ (V]3w  
return nSplitter; P)J-'2{  
} w^$C\bCbh  
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public void setNSplitter(int nCount) hp
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{ y$SUYG'v  
nSplitter = nCount; |5O>7~Tp  
} $~W5! m  
} &}
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/*
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**Utility.java El;"7Qn  
*/ <r
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package NetFox; g=Vu'p 3u  
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public class Utility { &ah%^Z4um  
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public Utility() nReld :#T  
{ vZ"gCf3#?3  
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} \y]K]iv  
dnU-v7k,{  
//线程睡眠 .hR <{P  
public static void sleep(int nSecond) 4n7Kz_!SVf  
{ ._^ne=Lx  
try{ L-C^7[48=  
Thread.sleep(nSecond); 9Ffam#  
} zIjfxK  
catch(Exception e) tm^joK[{|J  
{ ZL\^J8PRK  
e.printStackTrace (); Q47R`"  
} J 3C^tV  
} RO,TNS~  
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//日志 \&;y:4&l8  
public static void log(String sMsg) $5)#L$!,]  
{ UGy3B)  
System.err.println(sMsg);
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} ,.>9$(s  
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public static void log(int sMsg) 4^l9d  
{ 4oiE@y&{4  
System.err.println(sMsg); L%is"NZh  
} d$3md<lIB  
} >{tn2Fkg>  
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/* 0P9\;!Y  
**TestMethod.java dR1IndZl  
*/ *YvtT(Gt  
package NetFox; ;'8P/a$  
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H/x0'  
public class TestMethod { x"e;T,c  
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public TestMethod() *$fM}6}  
{ ///xx/weblogic60b2_win.exe xsj,l@Ey  
try{ K6p\ >J  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); nsU7cLf"^V  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); N'WTIM3W  
SiteFileFetch fileFetch = new SiteFileFetch(bean); vHcl7=)Q  
fileFetch.start(); RdWn =;  
} KYm8|]'g  
catch(Exception e){e.printStackTrace ();} s0f+AS|}  
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} u0&R*YV  
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public static void main(String[] args) Uq#2~0n>  
{ ~&D =;M/  
new TestMethod(); v.Bwg7R3  
} A&t8C8,  
} `+n#CWZ"Y  
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