http断点续传简单实现（java)

/* T+4Musu{V  
**SiteFileFetch.java sinG $=  
*/ 8a)EL*LH`  
package NetFox;
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import java.io.*; }}(~'
 
import java.net.*; Qw5M\   
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public class SiteFileFetch extends Thread { +ic~Sar  
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SiteInfoBean siteInfoBean = null; //文件信息Bean JrL/LGY  
long[] nStartPos; //开始位置 a*IJ)'S  
long[] nEndPos; //结束位置 BkqIfV%O  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 BS|-E6E<  
long nFileLength; //文件长度 |_=jXf\TL  
boolean bFirst = true; //是否第一次取文件 @xkM|N?  
boolean bStop = false; //停止标志 *
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File tmpFile; //文件下载的临时信息 &1':s|c  
DataOutputStream output; //输出到文件的输出流 *,
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） dnaf>G3  
public SiteFileFetch(SiteInfoBean bean) throws IOException _RmE+Xg2  
{ i~FCt4  
siteInfoBean = bean; ev guw*u  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); W>Rv  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Z.mV fy%  
if(tmpFile.exists ()) v S+~4Q41  
{ 1)PR]s:-m@  
bFirst = false; c,~44Z  
read_nPos(); z vYDE]  
} ' R@<4Ib|  
else X%F9.<4  
{ /1>  
nStartPos = new long[bean.getNSplitter()]; jN<]yhqf  
nEndPos = new long[bean.getNSplitter()]; BxT~1SBFq  
} P<&/$x6  
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} P3 Evv]sB@  
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public void run() m{5$4v,[
 
{ AP7W)S  
//获得文件长度 E0hp%:  
//分割文件 #<e7 Y0  
//实例FileSplitterFetch ,6bMfz  
//启动FileSplitterFetch线程
;' W5|.ZN  
//等待子线程返回 xq)/QR  
try{ y,>m#6hx#  
if(bFirst) 9M=K@a  
{ "$'~=' [  
nFileLength = getFileSize(); &sgwY  
if(nFileLength == -1) 3d<HIG^W}  
{ Q(IS=

 
System.err.println("File Length is not known!"); '9dtIW6E  
} eEh0T%9K  
else if(nFileLength == -2) M^f1D&A  
{ MB 5[Js|  
System.err.println("File is not access!"); U:|v(U$"?  
} H7=z%Y9y  
else |K-lgrA  
{ 6V?RES;X  
for(int i=0;i<nStartPos.length;i++) FlG^'UD  
{ \@3  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Y fA\#N0;3  
} sN}@b8o@  
for(int i=0;i<nEndPos.length-1;i++) 1Qu,]i`  
{ c):*R ]=  
nEndPos = nStartPos[i+1]; 90ag!  
} $?-o  
nEndPos[nEndPos.length-1] = nFileLength; {wXN kq  
} ')-(N um  
} Hu7zmh5
FF  
mO> M=2A  
CEq]B:[IC  
//启动子线程 tuUXW5!/  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ,O)\,tg  
for(int i=0;i<nStartPos.length;i++) )YtL=w?L'  
{ RbM~E~$  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), pe%)G6@G  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), cgeS)C7  
nStartPos,nEndPos,i); Ux T[  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ] *VF Ws  
fileSplitterFetch.start(); )o</gt)  
} U(=9&
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// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), O9X:1>a@i  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); D>e\OfTR:  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", l1Q+hz5"*U  
nEndPos = " + nFileLength); Pq>[q?>?  
// fileSplitterFetch[nPos.length-1].start(); I 47GQho  
g Pj0H&,.  
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//等待子线程结束 (zDk68=v  
//int count = 0; @h$0S+?:  
//是否结束while循环
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boolean breakWhile = false; dd7nO :]  
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while(!bStop) `A _8nW)  
{ 9PqgBq   
write_nPos(); U"Hquo  
Utility.sleep(500); 3t{leuO'  
breakWhile = true; @H%=%ZwpO  
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for(int i=0;i<nStartPos.length;i++) ls7A5 <  
{ [ky6E*dV`  
if(!fileSplitterFetch.bDownOver) ![]I%'s  
{ )c >B2
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breakWhile = false; /+t[,  
break; &:I +]G/W  
} kF,\bM  
} =&VXn{e  
if(breakWhile) 3|+f si)x  
break; H..ZvGu  
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//count++; !GGGh0Bj  
//if(count>4) niHL/\7u  
// siteStop(); jJ"EGFa8  
} s P4,S(+e  
71"JL",  
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System.err.println("文件下载结束！"); 53t-'K0l  
} 8Cs
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catch(Exception e){e.printStackTrace ();} [&qbc#L  
} a950M7  
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//获得文件长度 /4 LR0`A'  
public long getFileSize() 42>m,fb2[  
{ iqednk%  
int nFileLength = -1; %L13Jsw  
try{ Kxl,] |e>  
URL url = new URL(siteInfoBean.getSSiteURL()); V}|v!h[O8  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); zYG,x*IH  
httpConnection.setRequestProperty("User-Agent","NetFox"); "8muMa8Q%  
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int responseCode=httpConnection.getResponseCode(); yLz,V}  
if(responseCode>=400) z34>,0  
{ CC>fm1#i\  
processErrorCode(responseCode); >U~|R=*  
return -2; //-2 represent access is error DqzA U7  
} .?0>5-SfY  
ljJz#+H2_  
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String sHeader; >GznG[Ku  
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for(int i=1;;i++) N8XC~Dh{  
{ J,1osG<6x  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); +~4bB$6*4)  
//Utility.log(in.readLine()); R@<_Hb;Aeb  
sHeader=httpConnection.getHeaderFieldKey(i); 0/:=wn^pg  
if(sHeader!=null) uPFHlT  
{ II-$WJy  
if(sHeader.equals("Content-Length")) zd9]qo  
{ inBPT~
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nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 0Ox|^V  
break; ]`@]<6  
} *F szGn<  
} r6n5Jz  
else Aa`MK$29F  
break; T")i+
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} \+{t4Im  
} r9] rN  
catch(IOException e){e.printStackTrace ();} v:"m  
catch(Exception e){e.printStackTrace ();} Y%/ YFO2vb  
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Utility.log(nFileLength); {M@@)27gW  
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return nFileLength; _3.G\/>[K  
} p/hvQyE  
w<Yv`$-`  
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//保存下载信息（文件指针位置） W`N}  
private void write_nPos() W]
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{ -MrtliepW*  
try{ Eq=wdI  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 7 DY WdDX  
output.writeInt(nStartPos.length); /bmXDDYH4  
for(int i=0;i<nStartPos.length;i++) feI./E  
{ +mc[S  
// output.writeLong(nPos); l`b1%0y  
output.writeLong(fileSplitterFetch.nStartPos); Uvh~B^6  
output.writeLong(fileSplitterFetch.nEndPos);
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}
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output.close(); Y$`eg|$  
} I7fb}j`/  
catch(IOException e){e.printStackTrace ();} *#1y6^  
catch(Exception e){e.printStackTrace ();} rBD(2M  
} 2$ |]Vj*Zs  
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//读取保存的下载信息（文件指针位置） FjZc#\^9  
private void read_nPos() V06CCy8n  
{ `ke3+%uj o  
try{ D0/DI  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); dn
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int nCount = input.readInt(); S9G+#[.|  
nStartPos = new long[nCount]; /2;dH]o0  
nEndPos = new long[nCount]; E dn[c
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for(int i=0;i<nStartPos.length;i++) Xnv@H:$mxk  
{ (#6AKr9K  
nStartPos = input.readLong(); &~~aAg  
nEndPos = input.readLong(); `KpFH.k.K  
} c~}={4M]  
input.close(); bVoU|`c  
} 76-jMcGi  
catch(IOException e){e.printStackTrace ();} 7G5y)Qb  
catch(Exception e){e.printStackTrace ();} 0n:?sFY>  
} TN35CaSmq  
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private void processErrorCode(int nErrorCode) >
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{ ~x|aoozL  
System.err.println("Error Code : " + nErrorCode); ~:>AR` 9G  
} L[?nST18%  
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//停止文件下载 q,B3ru.?d  
public void siteStop() e~{^oM  
{ FR x6c  
bStop = true; _eJXi,  
for(int i=0;i<nStartPos.length;i++) w6T[hZ 9  
fileSplitterFetch.splitterStop(); &{%MjKJ._  
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} }q%jO  
} 2_;]  
//负责部分文件的抓取 nPcS3!7B#  
**FileSplitterFetch.java  i"vawxm  
*/ 9!9> ?Z  
package NetFox; \dRzS@l  
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import java.io.*; ' .B.V?7  
import java.net.*; Q%ruQ#  
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public class FileSplitterFetch extends Thread { yN*:.al  
o=pt_!i/  
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String sURL; //File URL R7K!A %  
long nStartPos; //File Snippet Start Position B?LXI3sQZ  
long nEndPos; //File Snippet End Position 25:Z;J>  
int nThreadID; //Thread's ID x#VyQ[ok  
boolean bDownOver = false; //Downing is over 0$6*o}N%  
boolean bStop = false; //Stop identical *5'.!g('  
FileAccessI fileAccessI = null; //File Access interface [oV{83f  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 6*IpA
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{ \PpXL*.  
this.sURL = sURL; 7K&}C;+  
this.nStartPos = nStart; ?d$"[lKX  
this.nEndPos = nEnd; E
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nThreadID = id; 9
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fileAccessI = new FileAccessI(sName,nStartPos);//定位 }g`Gh|
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} }e 9!xA  
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public void run() n`q2s'Pc  
{ rH&G<o&,  
while(nStartPos < nEndPos && !bStop) aD9rp V  
{ mwh{"FL(  
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try{ rK7W(D
}  
URL url = new URL(sURL); '0|o`qoLzA  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 7JUbVa%  
httpConnection.setRequestProperty("User-Agent","NetFox"); +t98@  
String sProperty = "bytes="+nStartPos+"-"; DkgUvn/S  
httpConnection.setRequestProperty("RANGE",sProperty); z8HsYf(!  
Utility.log(sProperty); Yd:Q`#7A  
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InputStream input = httpConnection.getInputStream(); {Oj7  
//logResponseHead(httpConnection); |uI?ySF  
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byte[] b = new byte[1024]; `>6T&  
int nRead; MRfb[p3Cx  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) -DP*q3  
{ !9;)N,  
nStartPos += fileAccessI.write(b,0,nRead); ,_jC$  
//if(nThreadID == 1) @x1%)1  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); @o>EBZ7MS  
} 22 &'@C>  
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Utility.log("Thread " + nThreadID + " is over!"); S]^`woD  
bDownOver = true; dAc ?O-~  
//nPos = fileAccessI.write (b,0,nRead); 2*[QZ9U[@  
} ~i ,"87$[  
catch(Exception e){e.printStackTrace ();} 0,_b)  
} ;o0#(xVz  
} }7ehF6  
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//打印回应的头信息 ,2L$G&?  
public void logResponseHead(HttpURLConnection con) X32C}4-B  
{ gl{B=NN  
for(int i=1;;i++) {tw+#}T a  
{ \'Ssn(s  
String header=con.getHeaderFieldKey(i); wN97_Y=`n  
if(header!=null) %{!R l@  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); C&+6>L@  
Utility.log(header+" : "+con.getHeaderField(header)); Fv8f+)k)Z~  
else /7D<'MF  
break; ,\YAnKn6_  
} mM_ k^4:  
} qnChM;)  
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public void splitterStop() , sjh^-;  
{ thc <xxRP  
bStop = true; _Mk7U@j+9  
} *27*>W1  
}rq9I"/L  
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} KkcXNjPVS  
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zF`3gl.  
/* rf.`h{!!  
**FileAccess.java 8)L*AdDAW!  
*//文件访问(定位，写) /@"Y^  
package NetFox; :"Y*<=x#2  
import java.io.*; I|9 SiZ0  
7B7&9<gc  
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public class FileAccessI implements Serializable{ E5</h"1  
M
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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 Z hd#:d  
RandomAccessFile oSavedFile; OhVs#^  
long nPos; %Ip*Kq-  
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public FileAccessI() throws IOException B07v^!Z>  
{ YJ_\Ns+Ow  
this("",0); zmI]cD@G  
} *JX;|S  
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hI}
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public FileAccessI(String sName,long nPos) throws IOException s58C2  
{ :e<7d8E5n{  
oSavedFile = new RandomAccessFile(sName,"rw"); b[I8iSkfi  
this.nPos = nPos; l(;Kij  
oSavedFile.seek(nPos); */^QH@P  
} cPDQ1qre!  
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public synchronized int write(byte[] b,int nStart,int nLen) :9|\Z|S(I  
{ I%j_"r9-I  
int n = -1; PPkx4S_>  
try{ =K\r-'V  
oSavedFile.write(b,nStart,nLen); ~PnTaAPJ  
n = nLen; Fv74bC%  
} h[o6-f<D  
catch(IOException e) zZ=pP5y8  
{ #P<N^[m  
e.printStackTrace (); Hnk:K9u.B:  
} "ZwKk G  
,<-G<${  
#|[ M?3  
return n; 6eFp8bANN#  
} 7aV%=_  
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} vS\Nd1~?  
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f>`dF?^6  
/* HpZ1xT  
**SiteInfoBean.java N@ \&1I`c$  
*/ EU7|,>a  
package NetFox; V!v:]E  
f| _u7"OX  
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public class SiteInfoBean { jhu07HX_  
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private String sSiteURL; //Site's URL yAL[[  
private String sFilePath; //Saved File's Path GZI`jS"lU  
private String sFileName; //Saved File's Name >NYW{(j  
private int nSplitter; //Count of Splited Downloading File wX >*H  
#$1Z
 
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public SiteInfoBean() I[)%,jd  
{//nSplitter的缺省值为5 Od f[*  
//default value of nSplitter is 5 7xRl9  
this("","","",5); &xRo^iV?  
} Q></`QWpoB  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) "&/-N[is  
{ c\a_VRN>r  
sSiteURL= sURL; '5&s=M_  
sFilePath = sPath; .<@8gNm3  
sFileName = sName; #@<9S{F  
this.nSplitter = nSpiltter; [8tL"G6s  
jCbV,0)^  
_SW3_8SuM.  
} ;rc`OZyE  
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public String getSSiteURL() -f*P nxg  
{ sMu] /'7  
return sSiteURL; ]a5 f2lE  
} X}+>!%W!}  
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public void setSSiteURL(String value) '!/<P"5t  
{ hzk
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sSiteURL = value; UQ{L{H   
} Z&;uh_EC  
vZ.x{
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public String getSFilePath() ``wS
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{ s"t$0cH9  
return sFilePath; ,l<6GB2\  
} 'Lu__NfN  
H$y-8-&)  
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public void setSFilePath(String value) &Z`#cMR{H  
{ hCC<?5q  
sFilePath = value; (1#J%  
} T}8Y6N<\m  
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public String getSFileName() ?Y@N`S  
{ z CvKDlL  
return sFileName; zux{S;:?  
} iyg*Xbmi~.  
A!h`]%0B  
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public void setSFileName(String value) @nux9MX
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{ v%q0OX>9X"  
sFileName = value; .ev?"!Vpp9  
} _H5o'>=  
HS
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1fpQLaT  
public int getNSplitter() 8P|D13- Q  
{ DAXX;4  
return nSplitter; e J6$-r  
} q^Y-}=w  
'IwNTM  
u fw]=h)  
public void setNSplitter(int nCount) RS8Hf~0G  
{ \SBc;  
nSplitter = nCount; b:TLV`>/&  
} N<XNTf  
} E"5*Ei)^3  
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d~i+ I5  
/* NfjE`  
**Utility.java >Z'NXha  
*/ / G7vwC  
package NetFox; ^zQ/mo,Z  
a6uJYhS~  
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public class Utility { =w{Z@S(ukz  
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public Utility() _sTROd)Vh  
{ )8$=C#qC[  
^G}47(  

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} =Jyu4j *}  
iMDM1}b  
//线程睡眠 ~kEI4}O  
public static void sleep(int nSecond) uFinv2Z'  
{ ~v|>xqWV  
try{ `u&Rsz&^  
Thread.sleep(nSecond); @U& QI*  
} #Up86(Z  
catch(Exception e) q1d}{DU  
{ 9,:l8  
e.printStackTrace (); -C(crn  
} v0H@Eg_  
} SC)g^E#  
dtRwTUMe?  
//日志 paCV!tP  
public static void log(String sMsg) %z,mB$LY  
{ rWR}Stc@
]  
System.err.println(sMsg); 7%x[q}  
} qKr8)}h  
~d|A!S`  
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public static void log(int sMsg) JR@`2YP-  
{ hG12ZZD  
System.err.println(sMsg); EVsC>rz  
} Pg
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} Lh!J >  
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/* T[UN@^DP(  
**TestMethod.java svcK?^ HTe  
*/ F%@aB<Nu  
package NetFox; BBwy,\o#  
 3KlbP  
gd`!tRcNY  
public class TestMethod { i@"@9n~  
+M\`#i\g>  
q_A!'sm@)  
public TestMethod() Vt:~q{9*k  
{ ///xx/weblogic60b2_win.exe iTgt}]L  
try{ su{poQ}K  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); <lx
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//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); &8Cu#^3  
SiteFileFetch fileFetch = new SiteFileFetch(bean); mwHB(7YS,  
fileFetch.start(); $P^q!H4D  
} < $lCkSx<Q  
catch(Exception e){e.printStackTrace ();} YNKHN2E8  
chM%]|gey  
&^}1O:8e  
} a|t$l=|DD  
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9
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public static void main(String[] args) `{3<{wgw  
{ L*xhGoC=  
new TestMethod(); cQy2"vtU  
} zPn+V7F  
} "O3tq=Q  
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