http断点续传简单实现（java)

/* Za>0&Fnf  
**SiteFileFetch.java z0v|%&IK  
*/ _[kZ:#  
package NetFox; x=7qC#+)  
import java.io.*; Wpdn^=dhL  
import java.net.*; p bT sn  
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public class SiteFileFetch extends Thread { 0&W*U{0F\  
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SiteInfoBean siteInfoBean = null; //文件信息Bean zDD1EycH  
long[] nStartPos; //开始位置 SXJ]()L?[v  
long[] nEndPos; //结束位置 (c'kZ9&  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 T
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long nFileLength; //文件长度 k
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boolean bFirst = true; //是否第一次取文件 
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boolean bStop = false; //停止标志 aOOkC&%  
File tmpFile; //文件下载的临时信息  (H*EZ  
DataOutputStream output; //输出到文件的输出流 z+=wql*Eo  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） d$;1%rRj8  
public SiteFileFetch(SiteInfoBean bean) throws IOException v<Ozr:lL  
{ #% 1|$V*:  
siteInfoBean = bean; %z_L}L  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); RoY"Haa  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); XSv)=]{  
if(tmpFile.exists ()) jW<aAd  
{ )d^b\On  
bFirst = false; w%NT 0J  
read_nPos(); Ia'm9Z*  
} 8euh]+  
else O\5q_>]  
{ IuW5LS  
nStartPos = new long[bean.getNSplitter()]; H+O^el  
nEndPos = new long[bean.getNSplitter()]; "AayU  
} )2YZ [~3  
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} q]}1/JZS  
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public void run() 2\'5LL3  
{ UomO^P  
//获得文件长度 @:M?Re`L  
//分割文件 |E7)s;}D  
//实例FileSplitterFetch *qN(_  
//启动FileSplitterFetch线程 uA1DTr?z  
//等待子线程返回 @0qDhv s  
try{ yrgb6)]nm@  
if(bFirst) HEMq4v4  
{ WokQ X"  
nFileLength = getFileSize(); k@RIM(^t  
if(nFileLength == -1) %CaUC'  
{ }2;{}J  
System.err.println("File Length is not known!"); D_(K{?KU  
} 1oVjx_I5y  
else if(nFileLength == -2) L74Sx0nk=  
{ 28jm*Cl8  
System.err.println("File is not access!"); L(ni6-  
}
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else D,)^l@UP  
{ I,Z'ed..  
for(int i=0;i<nStartPos.length;i++) (+=TKI<=  
{ ;xl_9Ht/  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); noLb  
} rjJ-ZRs\  
for(int i=0;i<nEndPos.length-1;i++) v."0igMO  
{ P?Fm<s:  
nEndPos = nStartPos[i+1]; s(3iGuT  
} /EXubU73  
nEndPos[nEndPos.length-1] = nFileLength; {W5
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} l*0`{R  
} TXDb5ZCzM  
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//启动子线程 ,VTX7
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; yS2[V,vS7  
for(int i=0;i<nStartPos.length;i++) SB<09|2  
{ <e%~K4KH  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), aDr
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Dn9AOi!  
nStartPos,nEndPos,i); /[|ODfY
 
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); .}6Mj]7?i  
fileSplitterFetch.start(); rcyq+wY #  
} fmv8)$W#U  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), &
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); SyWLPh  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", g0n 5&X  
nEndPos = " + nFileLength); {k#RWDespy  
// fileSplitterFetch[nPos.length-1].start(); 4\?GA`@  
-?K?P=B;X  
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//等待子线程结束 *wY { ~zh  
//int count = 0; e52y}'L  
//是否结束while循环 $sTvXf:g  
boolean breakWhile = false; 4CdST3  
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while(!bStop) a|s64+  
{ #ivN-WKCl  
write_nPos(); /j`vN  
Utility.sleep(500); j& x=?jX  
breakWhile = true; ]*Tnu98G}  
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for(int i=0;i<nStartPos.length;i++) >aaHN1Ca  
{ _H(:$=$Q  
if(!fileSplitterFetch.bDownOver) HR> X@g<c  
{ [61T$.  
breakWhile = false; WV8?zB1  
break; >dTJ  
} ,cqZb0VP{t  
} mI[$c"!BD  
if(breakWhile) J% t[{  
break; :.k)!  
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//count++; L
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//if(count>4) R>YDn|cWI  
// siteStop(); \B<A.,i4  
} .eSMI!Y=  
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V L&5TZtz  
System.err.println("文件下载结束！"); ,PyA$Z  
} \EC=#E(  
catch(Exception e){e.printStackTrace ();} p
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} D#~S<>u@  
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b3,&R
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//获得文件长度 o9Z!Z^  
public long getFileSize() f/&k$,w  
{ WRWcB  
int nFileLength = -1; mu!hD^fw  
try{ H:DTvv8e{  
URL url = new URL(siteInfoBean.getSSiteURL()); mh4`,N  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Y.<&phv  
httpConnection.setRequestProperty("User-Agent","NetFox"); p^s k?E  
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int responseCode=httpConnection.getResponseCode(); #O |Z\|n  
if(responseCode>=400) Fk 5;  
{ U/|H%b  
processErrorCode(responseCode); =R>%}5  
return -2; //-2 represent access is error w<uK-]t  
} qC%[J:RwF  
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String sHeader; d/Z258  
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for(int i=1;;i++) ;8G( l   
{ LD~s@}yH>  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); #0+`dI_5/  
//Utility.log(in.readLine()); PUdJ>U
 
sHeader=httpConnection.getHeaderFieldKey(i); NB z3j
  
if(sHeader!=null) FZEK-
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{ rX*ATN  
if(sHeader.equals("Content-Length")) M99gDN  
{ 2|1s!Q  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 0> 6;,pd"  
break; 3gn)q>Xj$  
} 4rh*&'  
} `y26OYo  
else DM-8azq $  
break; es` A<  
} n tfwR#j  
} Vo\RtM/6{  
catch(IOException e){e.printStackTrace ();} XQ
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catch(Exception e){e.printStackTrace ();} UI*^$7z1 +  
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Utility.log(nFileLength);  _`bH$  
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return nFileLength; G*;}6 bj|?  
} +!I7(gL  
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~)zoIM\  
//保存下载信息（文件指针位置） A-GRuC  
private void write_nPos() CZ/bO#~  
{ S[b)`Wi D  
try{ 9Q#eu~R  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 6!,Am^uXM  
output.writeInt(nStartPos.length); _Gf.1Bsf@S  
for(int i=0;i<nStartPos.length;i++) oH/4opV  
{ _/W[=c   
// output.writeLong(nPos); n: ~y]  
output.writeLong(fileSplitterFetch.nStartPos); C6XTId=y#_  
output.writeLong(fileSplitterFetch.nEndPos); [3s p  
} vu%:0p`K  
output.close(); }@*Me+
 
} !*0\Yi,6  
catch(IOException e){e.printStackTrace ();} R?Dbv'lp>  
catch(Exception e){e.printStackTrace ();} ~ E)[!y  
} K8`M~P.  
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3sk$B%a>Z  
//读取保存的下载信息（文件指针位置） I$Q%iZ{  
private void read_nPos() i4Y_5  
{ *ay>MlcV2=  
try{ ?,JN?  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Dj<]eG]  
int nCount = input.readInt(); yn0OPjH
 
nStartPos = new long[nCount]; ZD9UE3-  
nEndPos = new long[nCount]; EBY=ccGE{  
for(int i=0;i<nStartPos.length;i++) !OJ@ =y`i  
{ ,t+5(qi  
nStartPos = input.readLong(); 3gW4\2|T  
nEndPos = input.readLong(); K)Nbl^6x  
} ob  
input.close(); v5|X=B>&>  
} k
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catch(IOException e){e.printStackTrace ();} ,KlTitJl\+  
catch(Exception e){e.printStackTrace ();} |5wuYG  
} g& yR-  
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9})!~r;|  
private void processErrorCode(int nErrorCode) 41<.e`{  
{ 8t$a8 PE  
System.err.println("Error Code : " + nErrorCode); t5z6{`  
} `L(AvSR  
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^|6%~jkD5  
//停止文件下载 B)F2SK<@  
public void siteStop() 5#zwdoQ  
{ }2.^n{Y  
bStop = true; v hUn3|  
for(int i=0;i<nStartPos.length;i++) 
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fileSplitterFetch.splitterStop(); s D]W/  
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u
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}  0gBD  
} rO% |PRP  
//负责部分文件的抓取 ?Uzs^rsb  
**FileSplitterFetch.java D<[4}og&]  
*/ \A\a=A[  
package NetFox; xo0",i f8  
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import java.io.*; ui4H(A'}  
import java.net.*; =:U63  
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public class FileSplitterFetch extends Thread { 5Qp5JMK  
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String sURL; //File URL ;p"G<n  
long nStartPos; //File Snippet Start Position 5=g{%X  
long nEndPos; //File Snippet End Position G
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int nThreadID; //Thread's ID H#8]Lb@@:  
boolean bDownOver = false; //Downing is over p+ymtPF  
boolean bStop = false; //Stop identical OHzI!,2]  
FileAccessI fileAccessI = null; //File Access interface m :ROq  
br"p D-}  
+
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException uXuMt a*Y  
{ o<e AZ  
this.sURL = sURL; +XU*NAD,!  
this.nStartPos = nStart; NYD#I{h  
this.nEndPos = nEnd; VdR5ZP  
nThreadID = id; CTt3W>'=+  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 06I'#:]  
} $|!VP'VI  
{A4"KX(U  
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public void run() M_V\mYC8I  
{ "k\W2,q[  
while(nStartPos < nEndPos && !bStop) VrhG=CK  
{ b1>%%#  
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try{ vBd^=O  
URL url = new URL(sURL); TuphCu+Oh  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 4YkH;!M>ji  
httpConnection.setRequestProperty("User-Agent","NetFox");  o@_pV  
String sProperty = "bytes="+nStartPos+"-"; U]dz_%CRP  
httpConnection.setRequestProperty("RANGE",sProperty); "])X0z yM  
Utility.log(sProperty); $=n|MbFl  
/Cr0jWu _  
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InputStream input = httpConnection.getInputStream(); A>^\jIB>  
//logResponseHead(httpConnection); i% k`/X;  
:|oH11y  
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byte[] b = new byte[1024]; )Y@  
int nRead; ^;GJ7y&,d  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) \;p5Pagx0-  
{ FsZF>vaV  
nStartPos += fileAccessI.write(b,0,nRead); ^r^cMksB*  
//if(nThreadID == 1) `9eE139V='  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); \1f$]oS  
} ?gjM]Ki%:  

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Utility.log("Thread " + nThreadID + " is over!"); gNl@T  
bDownOver = true; gOa'o<  
//nPos = fileAccessI.write (b,0,nRead); PdJtJqA8h\  
} yowvq4e  
catch(Exception e){e.printStackTrace ();} JP9eNc[  
} R{kZKD=  
} wQ[~7 ,o  
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//打印回应的头信息 {Q^P<  
public void logResponseHead(HttpURLConnection con) ]*U\ gm%  
{ DM{7x77  
for(int i=1;;i++) AV AF!Z  
{ q~.\NKc  
String header=con.getHeaderFieldKey(i); =jip* E^  
if(header!=null) ,JRYG<O_T  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); -]\%a=]  
Utility.log(header+" : "+con.getHeaderField(header)); URm
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else gKcP\m  
break; `DO`c>>K  
} 0U ?1Yh7 m  
} mkT
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|4
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public void splitterStop() ^~|P[}  
{ _;$VH4(BI  
bStop = true; 'Wl))lB  
} &fq-U5zH  
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} / O6n[qj|  
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/* ;%odN d  
**FileAccess.java 3zY"9KUN  
*//文件访问(定位，写) ?s#DD,  
package NetFox; "P.7FD  
import java.io.*; VR2BdfKU,  
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il\#R%';5  
public class FileAccessI implements Serializable{ Lo @mQ  
0@{K'm/  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 X !NH?0)  
RandomAccessFile oSavedFile; ;2kiEATQ 1  
long nPos; `,Q uO  
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public FileAccessI() throws IOException `Z>4}<~+  
{ :}FMauHh  
this("",0); . [+ObF9=  
} Y(78qs1w  
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public FileAccessI(String sName,long nPos) throws IOException FVT_%"%C9  
{ ]plg@  
oSavedFile = new RandomAccessFile(sName,"rw"); T/MbEqAf  
this.nPos = nPos; KQaw*T[Q3w  
oSavedFile.seek(nPos); fyYT#r  
} c^}gJ  
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public synchronized int write(byte[] b,int nStart,int nLen) DY^q_+[V  
{ ?QwDV`  
int n = -1; K=M5d^K<E  
try{ 724E(?>J  
oSavedFile.write(b,nStart,nLen); rOE[c  
n = nLen; }:5r#Cd  
} +dSe"W9  
catch(IOException e) i>_V?OT#5  
{ ;n00kel$  
e.printStackTrace (); 0^*4LM|z  
} ?Q="w5OOD  
w
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return n; :g}WN  
} <tMiI)0%  
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} IX']s;b  
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/* jAfUz7@  
**SiteInfoBean.java zK(9k0+s  
*/ }?$d~]t)  
package NetFox; fBR,Oneo  
9(QY~F  
*eH[~4  
public class SiteInfoBean { HY~\e|o  
q!$ZBw-7>A  
m!er"0  
private String sSiteURL; //Site's URL pi q%b]  
private String sFilePath; //Saved File's Path I?lQN$A.E  
private String sFileName; //Saved File's Name 320Wm)u>:  
private int nSplitter; //Count of Splited Downloading File ,jQkR^]j-  
-1Yt3M&  
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public SiteInfoBean()
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{//nSplitter的缺省值为5 p )etl5  
//default value of nSplitter is 5 ba1zu|@w  
this("","","",5); 6vQAeuz<Fq  
} KVvIo1$N  
 MScj
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 8&qCH>Cf  
{ t(?m!Z?tb  
sSiteURL= sURL; eVjr/nm  
sFilePath = sPath; 2BS2$#c>  
sFileName = sName; S)C =Q~&  
this.nSplitter = nSpiltter; T12?'JL^r  
:[#HP66[O5  
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} f7)}A/$4+  
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&"BmCDOq  
public String getSSiteURL() ?=dyU(  
{ &Y\Vh}  
return sSiteURL; k`
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} {oy(08`6  
yyPkjUy[  
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public void setSSiteURL(String value) AA;\7;k{  
{ eG72=l)Mz  
sSiteURL = value; puG$\D-[  
} ^6Q(he  
/FJAI  
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public String getSFilePath() y>'^<xk  
{ OthQ)&pqX  
return sFilePath; 30
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} W
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public void setSFilePath(String value) UO5^4  
{ ,}2M'DSWa  
sFilePath = value; 9`f]Rf"  
} >:4}OylhM  
tQ< ou,  

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public String getSFileName() BEPeK  
{ ,@tYD(Z  
return sFileName; \m1r(*Ar  
} ls
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3Ew-Ia%A  
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public void setSFileName(String value) ~P 1(%FZ  
{ K||9m+  
sFileName = value; ^&am]W;T  
} ^*#5iT8/  
tj;<Z.  
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public int getNSplitter() TFb9gOTJ  
{ +yiGZV/X  
return nSplitter; rBye%rQRq  
} 1/c7((]7(,  
'IY?7+[  
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public void setNSplitter(int nCount) P#\L6EO.  
{
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nSplitter = nCount; ~b+4rYNxU_  
} }o0R`15dA  
} i64a]=  
*F1!=:&s  
{(U?)4@  
/* EpB2?XGA  
**Utility.java `YVdIDl]  
*/ YK!nV ,  
package NetFox; >KH.~Jfy  
<]eWr:;  
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public class Utility { n"N!76  
~Os"dAgZFY  
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public Utility() 75v 5/5zRn  
{ Bwj^9J/ob  
} 1^/[?  
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} 2Vas`/~u~  
`*mctjSN  
//线程睡眠 jq yqOhb4  
public static void sleep(int nSecond) *kY\,r&!P  
{ AP'UcA  
try{ v]& )+0  
Thread.sleep(nSecond); XrS.[  
} -^]8wQU  
catch(Exception e) Ch%W C,  
{ 57k@]3 4  
e.printStackTrace (); kA1]o  
} |6'(yn  
} ?lW-NPr  
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//日志 -'
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public static void log(String sMsg) 0ubT/  
{ 6S)$wj*
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System.err.println(sMsg); WF,<7mx=-  
} }u:@:}8K  
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j|gQe .,1  
public static void log(int sMsg) 28[hp[<  
{ ,l^; ZE  
System.err.println(sMsg); |=
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} ^2%_AP0=  
} :IlRn`9X`  
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,*$L_itL  
/* `WQz_}TqB  
**TestMethod.java /yPFts_q  
*/ ,~u5SR  
package NetFox; F$<>JEdX  
Nd'+s>d0
 
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public class TestMethod { M}=X/*T  
" 2A`M~  
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public TestMethod() & 9}L +/,  
{ ///xx/weblogic60b2_win.exe (jd)sf6Tj[  
try{ by!1L1[JTt  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); j oDY   
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Zz}Wg@&  
SiteFileFetch fileFetch = new SiteFileFetch(bean); >Eg/ir0  
fileFetch.start(); t0h@i`  
} nI7G"f[%r;  
catch(Exception e){e.printStackTrace ();} Sm-gi|A  
gw' uY$  
^kJ(bBY  
} ^0vK >  
z+,l"#Vv  
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public static void main(String[] args) x>:~=#Vi  
{ *"Yz"PK  
new TestMethod(); ,rj_P  
} Qz)1wf'y  
} xj`ni G  
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