http断点续传简单实现（java)

/* wJF Fg :  
**SiteFileFetch.java $N`uM  
*/ ?FRQ!R  
package NetFox; fl18x;^I  
import java.io.*; u#m(Py  
import java.net.*; BlvNBB1^  
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public class SiteFileFetch extends Thread { u:7=Yy :  
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SiteInfoBean siteInfoBean = null; //文件信息Bean UZUG?UUM  
long[] nStartPos; //开始位置 .1C|J  
long[] nEndPos; //结束位置 3`aJ"qQE  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ,*$/2nB^  
long nFileLength; //文件长度 Bt^];DjH  
boolean bFirst = true; //是否第一次取文件 K\GIh8L  
boolean bStop = false; //停止标志 ,Uv8[ci%9  
File tmpFile; //文件下载的临时信息 f{[,
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DataOutputStream output; //输出到文件的输出流 YJ{d\j  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） .DkDMg1US  
public SiteFileFetch(SiteInfoBean bean) throws IOException L5*,l`lET  
{ "yCe
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siteInfoBean = bean; TAt9+\'  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ,`JXBI~  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); oFeflcSz  
if(tmpFile.exists ()) B<Ynx_95  
{ ;ckv$S[p  
bFirst = false; d#eHX|+  
read_nPos(); :`ysq  
} w5(GRAH  
else Z0e+CEzq  
{
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nStartPos = new long[bean.getNSplitter()]; IJnr^S8  
nEndPos = new long[bean.getNSplitter()]; J}.y+b>8
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} fV.43E  
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} OQh36BM  
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public void run() 6YZ&>`a^  
{ ,
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//获得文件长度 /m;w~-N  
//分割文件 Vy:ER  
//实例FileSplitterFetch NB&u^8b  
//启动FileSplitterFetch线程 | We @p  
//等待子线程返回 'ga1SbA]  
try{ 1*x4T%RF$  
if(bFirst) +Hb6j02#  
{ G\H@lFh  
nFileLength = getFileSize(); @$79$:q N  
if(nFileLength == -1) j1>77C3  
{ ^~5tntb.  
System.err.println("File Length is not known!"); NoJo-vo*  
} -7">A~c  
else if(nFileLength == -2) MQ>vHapr  
{ '+X9MzU*\  
System.err.println("File is not access!"); 3A} ntA!  
} J 6S  
else I#Tl  
{ Hf %;FaJ=  
for(int i=0;i<nStartPos.length;i++) ^aZ Wu|p  
{ +>OEp
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); DZXv3gnX  
} nu$LWC-  
for(int i=0;i<nEndPos.length-1;i++) `z3?ET  
{ kx1-.~)p(z  
nEndPos = nStartPos[i+1]; d~|qx  
} _V{WXsOx(  
nEndPos[nEndPos.length-1] = nFileLength; =dX*:An  
} zoOm[X=?3  
} ?XGZp?6  
%p2C5z?  
 aG\m3r  
//启动子线程 0{PK]qp7  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; d<6L&8)<  
for(int i=0;i<nStartPos.length;i++) _uHyE }d  
{ kQIWDN  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), fINM$ 6  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), cx2s|@u0  
nStartPos,nEndPos,i); ~9oS~fP?I  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); =
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fileSplitterFetch.start(); Sjr(e}*  
} F;ONo.v;  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), TL7-uH  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); O|j5ulO}&"  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 8XJ%Yuu  
nEndPos = " + nFileLength); @;<w"j`r  
// fileSplitterFetch[nPos.length-1].start(); ]jHB'Y  
317Buk  
]V@!kg(p8  
//等待子线程结束 NE9e brK  
//int count = 0; I/WnF"yP  
//是否结束while循环 r 'jVF'w  
boolean breakWhile = false; _n}!1(xYa`  
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59^@K"J  
while(!bStop) '*3+'>  
{ iMp)g%Ng  
write_nPos(); 2 yP#:T/z  
Utility.sleep(500); \k1Wh-3  
breakWhile = true; Gcs+@7!b  
9$DVG/  
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for(int i=0;i<nStartPos.length;i++)  74Q?%X  
{ g>im2AD+e  
if(!fileSplitterFetch.bDownOver) ^1cqx]>E  
{ Y5MHd>m  
breakWhile = false; m'qMcCE  
break; ^m1Rw|  
} .X2mEnh  
} c>UITM=!I  
if(breakWhile) 2CxdNj  
break; ?|hzAF"U  
0KDDAkR5R  
,Fr{i1Ky  
//count++; -~(0:@o ;  
//if(count>4) u8<=FV3  
// siteStop(); x:2[E-  
} iqoPD4A  
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t'Q48QAb?  
System.err.println("文件下载结束！"); _ _)Z Q  
} IeU.T@ $  
catch(Exception e){e.printStackTrace ();} x9_ Lt4  
} H7SqM D*y9  
+Zr03B  
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//获得文件长度 "Z{^i3gN  
public long getFileSize() nlY ^  
{ W;-Qze\D  
int nFileLength = -1;
u%h<5WNh<  
try{ }dXL= ul  
URL url = new URL(siteInfoBean.getSSiteURL()); v%FV
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); lpp'.HTP  
httpConnection.setRequestProperty("User-Agent","NetFox"); J5o"JRJ"  
So8P8TCK  
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int responseCode=httpConnection.getResponseCode(); 7CIje=u.q  
if(responseCode>=400) Zwt!nh  
{ 
,5\n%J:  
processErrorCode(responseCode); gEe}xI  
return -2; //-2 represent access is error 8@qahEgQ  
} MoX*e  
n
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;  
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String sHeader; A!f0AEA,  

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for(int i=1;;i++) NPc%}V&C(u  
{ pj )I4C)  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); T5Fah#-4  
//Utility.log(in.readLine()); w}1)am&pD  
sHeader=httpConnection.getHeaderFieldKey(i); Sph+kiy|  
if(sHeader!=null) =_1" d$S&  
{ ld?M,Qd  
if(sHeader.equals("Content-Length")) 2~@=ua[|=5  
{ sS|zz,y  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 4Ek< 5s[  
break; .6"7Xxe]<  
} an7N<-?
 
} f@}(<#  
else o+t?OG/0  
break; zm}
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} evs2dz<e
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} -(iJ<  
catch(IOException e){e.printStackTrace ();} {e@1,19  
catch(Exception e){e.printStackTrace ();} p&\uF#I;  
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}F.1j!71L  
Utility.log(nFileLength); vP?yl "U  
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-?(RoWv@X&  
return nFileLength; a@a1/3  
} /0c&!OP  
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4J_%quxO  
//保存下载信息（文件指针位置） 1)R)+`y  
private void write_nPos() z%KC
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{ w#1dO~  
try{ t}tKm  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 4Klfnki  
output.writeInt(nStartPos.length); QXz!1o+"  
for(int i=0;i<nStartPos.length;i++) S&Sf}uK  
{ zXD@M{  
// output.writeLong(nPos); 4[ra  
output.writeLong(fileSplitterFetch.nStartPos); S'O0'5U@  
output.writeLong(fileSplitterFetch.nEndPos);
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} + ND9###  
output.close(); .3&m:P8zV  
} ;H=6u  
catch(IOException e){e.printStackTrace ();} %;5hHRA  
catch(Exception e){e.printStackTrace ();} TGNeEYr  
} $>
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}:mI6zsNj  
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//读取保存的下载信息（文件指针位置） $!f$R`R^Q\  
private void read_nPos() h$&XQq0T  
{ t5k&xV=~ #  
try{ )yP>}ME  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 7" [;M  
int nCount = input.readInt(); ts]7 + 6V  
nStartPos = new long[nCount]; .9xGLmg  
nEndPos = new long[nCount]; Ae#6=]V+^  
for(int i=0;i<nStartPos.length;i++) hF~B&^dd.  
{ (Gn[T1p?  
nStartPos = input.readLong(); $ZU(bEUOG  
nEndPos = input.readLong(); ~c^-DAgB  
} {P-PH$ E-  
input.close(); ]G B},  
} `9+EhP$RS  
catch(IOException e){e.printStackTrace ();} IO#W#wW$M  
catch(Exception e){e.printStackTrace ();} XbC8t &Q],  
} &J b.OCf  

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["}A#cO652  
private void processErrorCode(int nErrorCode) Cf7\>U->  
{ x\rZoF.NQ  
System.err.println("Error Code : " + nErrorCode); [f0HUbPX  
} }'W^Ki$  
| #Pc e  
qM0MSwvC=  
//停止文件下载 +joE  
public void siteStop() ECScx02  
{ !iVFzG @m  
bStop = true; )ta5y7np  
for(int i=0;i<nStartPos.length;i++) 6dL>Rzl$Dk  
fileSplitterFetch.splitterStop(); qt(:bEr^6b  
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} 4AYc8Z#'  
} Xoy1Gi?  
//负责部分文件的抓取 zq.&Mw
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**FileSplitterFetch.java FW DuH`-5  
*/ O+?zn:  
package NetFox; kPH^X}O$  
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import java.io.*; ~ ""MeaM8[  
import java.net.*; q4i8Sp>  
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public class FileSplitterFetch extends Thread { #!jRY!2Vt  
>!1f`  
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String sURL; //File URL fWyDWU  
long nStartPos; //File Snippet Start Position :dN35Y]a  
long nEndPos; //File Snippet End Position /8}+#h)[  
int nThreadID; //Thread's ID Ye2];(M  
boolean bDownOver = false; //Downing is over V(u2{4gZ  
boolean bStop = false; //Stop identical >k}/$R+  
FileAccessI fileAccessI = null; //File Access interface Y:%)cUxA  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException e:LZs0  
{ dyzwJ70K  
this.sURL = sURL; }+ 2"?f|]  
this.nStartPos = nStart; *\KMkx  
this.nEndPos = nEnd; <IyL
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nThreadID = id; w3qf7{b  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 rA,Y_1b *  
} d7J[.^\  
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public void run() H?j-=Zka  
{ 4AOS}@~W  
while(nStartPos < nEndPos && !bStop) U;{,l
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{ MQ(/l_=zQ  
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try{ CQ.4,S}6'  
URL url = new URL(sURL); Y-q@~vZ]  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 5 ?~-Vv31s  
httpConnection.setRequestProperty("User-Agent","NetFox"); "42$AaS  
String sProperty = "bytes="+nStartPos+"-"; o U}t'WU  
httpConnection.setRequestProperty("RANGE",sProperty); P9"D[uz  
Utility.log(sProperty); v*~%x  
E#$_uZ4  
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InputStream input = httpConnection.getInputStream(); ./nYXREO|  
//logResponseHead(httpConnection); @MZ6E$I  
#)mkD4  
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byte[] b = new byte[1024]; x_y>j)  
int nRead; l8xd73D)8  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) +<\cd9  
{ RA/ =w&  
nStartPos += fileAccessI.write(b,0,nRead); 8U<.16+5Q  
//if(nThreadID == 1) mXU?+G0  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); aI{@]hCo  
} ~|Ih JzDt  
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Utility.log("Thread " + nThreadID + " is over!"); #4_O;]{'  
bDownOver = true; 7tl)4A6  
//nPos = fileAccessI.write (b,0,nRead); k]$E8[.t  
} 9hR:y.  
catch(Exception e){e.printStackTrace ();} K~Au?\{  
} r,.95@  
} J;=aIiN]R  
)_b@~fC  
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//打印回应的头信息 Ec*--]j*c  
public void logResponseHead(HttpURLConnection con) y>7VxX0xi  
{ <Xs@ \  
for(int i=1;;i++) ?%dCU~ z  
{ bpF@}#fT  
String header=con.getHeaderFieldKey(i); |T$a+lHMD  
if(header!=null) /[|}rqX(  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 
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Utility.log(header+" : "+con.getHeaderField(header)); )|Vg

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else b*FU*)<4.  
break; SEQO2`]e:  
} bm tJU3Rm  
} ?mYV\kDt\  
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public void splitterStop() cB|Cy{%
 
{ Jl}!CE@-  
bStop = true; |,a%z-l  
} LTYuxZ  
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} g~Nij~/  
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/* 5gc:Y`7t  
**FileAccess.java ]*g ss'N  
*//文件访问(定位，写) "lU]tIpCu  
package NetFox; K{=r.W  
import java.io.*; [I++>4  
7dufY }}  
gQI(=in  
public class FileAccessI implements Serializable{ tv@Z5  
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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 3Y1TQ;i,wQ  
RandomAccessFile oSavedFile; c<+g|@A#  
long nPos; zfP[1  
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2
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public FileAccessI() throws IOException 4[5lX C  
{ Sr ztTfY  
this("",0); g/U$!d_  
} 9{9#AI.G  
}j5R@I6P  
/\,
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public FileAccessI(String sName,long nPos) throws IOException Io,/ +#|  
{ {p#l!P
/  
oSavedFile = new RandomAccessFile(sName,"rw"); K)9j je  
this.nPos = nPos; H#kAm!H
 
oSavedFile.seek(nPos); 8"?Vcw&  
} SgCqxFii  
q(Z
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RR~sEUCo{  
public synchronized int write(byte[] b,int nStart,int nLen) w L/p.@  
{ k Z+q  
int n = -1; zH=/.31Q  
try{ vu_>U({. T  
oSavedFile.write(b,nStart,nLen); =A0"0D{\  
n = nLen; Z9J =vzsHE  
} !~lVv&YO  
catch(IOException e) 3P+4S|@q(4  
{ 3xmiX{1e  
e.printStackTrace (); r%Q8)
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} hkmTpH1<M  
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="5k\1W1M  
return n; r/N[7*i  
} tAb;/tM3I  
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} 7~!I2DV_  
==-7F3QP  
l#2r.q^$|  
/* #[k~RYS3  
**SiteInfoBean.java o ;[C(OS  
*/ YiIddQ  
package NetFox; sW]yuu!/  
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public class SiteInfoBean { I<D&,LFH*w  
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vKU]80T  
private String sSiteURL; //Site's URL dp"<KcP_  
private String sFilePath; //Saved File's Path ]97Xu_  
private String sFileName; //Saved File's Name .iOw0z  
private int nSplitter; //Count of Splited Downloading File LKK{j,g7  
<_BqpZ^`  
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public SiteInfoBean() ^w;o

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{//nSplitter的缺省值为5 _qC+'RE3  
//default value of nSplitter is 5 [<en1  
this("","","",5); yM(_P0  
} #6*V7@9]3|  
ZfFIX5Qd\  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) m+D2hK*  
{ .;<7424(%  
sSiteURL= sURL; pX>ua5Z  
sFilePath = sPath; 7%:??*"~  
sFileName = sName; Qq`3S>  
this.nSplitter = nSpiltter; NDB*BmG  
SKB@  
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} (,- 5(fW  
g2[K<  
L0X&03e=e:  
public String getSSiteURL() ]uBT &  
{ !pd7@FwC  
return sSiteURL; X0^zw^2W  
} X)FL[RO%q  
_N>wzkJ  
kN'|,eKH4  
public void setSSiteURL(String value) w;N{>)hv  
{ w"fCI13  
sSiteURL = value; +}Kk
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} a6;gBoV  
"_nX5J9  
+G5'kYzJ  
public String getSFilePath() 4ggVj*{v  
{ ]h #WkcXQ  
return sFilePath; GIl:3iB49  
} |RHO+J  
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EsT0"{  
public void setSFilePath(String value) ggrI>vaw  
{ jG+
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sFilePath = value; y,'FTP9?  
} <h'8w  
#Y;.>mF  
PRMZfYc  
public String getSFileName() 21.YO]Et  
{ !&@2  
return sFileName; 1P5*wNF  
} ~GNyE*t/Y  
GYFgEg}  
-(6eVI  
public void setSFileName(String value) .[edln  
{ pO\S#GnX  
sFileName = value; b0r,h)R  
} Ro$j1Aw(  
|C~Sr#6)7  
l)}<#Ri  
public int getNSplitter() /DLr(  
{ 4qqF v?O[r  
return nSplitter; x2sN\tOh^  
} @; W<dJ<X  
ceqFQ  
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public void setNSplitter(int nCount) $`^H:Djr  
{ ZkwJ.SuU  
nSplitter = nCount; B#J{F  
} $`E4m8fX  
} V78Mq:7d  
x*:n4FZ7b  
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/* !?yxh/>lM  
**Utility.java ^%-NPo<  
*/ 7^c2e*S  
package NetFox; kJ/+IGV^v  
A$/KP\0Y2  
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public class Utility { g* %bzfk=|  
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<MRC%!.  
public Utility() G?>qd}]y0L  
{ K3
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%wOOzp`  
y@q1c*|  
} QxKAXq@)i  
[.M  
//线程睡眠 ty':`)  
public static void sleep(int nSecond) QyTh!QM~`  
{ h!QjpzQe  
try{ &u&2D$K,tp  
Thread.sleep(nSecond);  }K?F7cD  
} )sqaR^  
catch(Exception e) 8^i\Y;6  
{ 5@K\c6  
e.printStackTrace (); bC6X?m=  
} c qv.dC  
} L%f
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aWdUu
id  
//日志 nZe\5`  
public static void log(String sMsg) AmZuo_  
{ bG52s  
System.err.println(sMsg); ~H
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} cnbo+U  
 /;+oz  
5Lw{0uLr  
public static void log(int sMsg) 2ed@HJu  
{ d"Bo8`_  
System.err.println(sMsg); .Xi2G@D  
} T
)`gm{T  
} #uB[&GG}W  
9-B@GFB;8  
D^N[=q99&e  
/* X@cSP7b  
**TestMethod.java ?b
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*/ eVTO#R*'|  
package NetFox; }&mj.
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{798=pC<.  
AYt*'Zeg!s  
public class TestMethod { !`Le`c  
CK=ARh#|  
Vfb<o"BQk  
public TestMethod() @?m+Z"o|z  
{ ///xx/weblogic60b2_win.exe `nK
JR'QC  
try{ >;m{{nj  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); #iiwD|  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); $khrWiX  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ej<`CQ  
fileFetch.start(); y`({ .L  
} }N@n{bu+  
catch(Exception e){e.printStackTrace ();} )TM!ms+K  
%U-Qsy8|D)  
$]Jf0_  
} 5|5=Y/  
A^8x1ydZ  
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public static void main(String[] args) -gB{:UYi3  
{ !1("(Eb  
new TestMethod(); _$!`VA%  
} pVY4q0@  
} D
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