http断点续传简单实现（java)

/* }%7NF*  
**SiteFileFetch.java nKa$1RMO  
*/ i|`dWOVb  
package NetFox; z2_6??tS/c  
import java.io.*; Fz#X=gmG  
import java.net.*; rf~Y
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public class SiteFileFetch extends Thread { i4Lc$20?d  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 4}+/F}TbJ5  
long[] nStartPos; //开始位置 g0R~&AN!g  
long[] nEndPos; //结束位置 h/?l4iR*  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 wE+${B03  
long nFileLength; //文件长度 '3zc|eJt&  
boolean bFirst = true; //是否第一次取文件 )nL`H^  
boolean bStop = false; //停止标志 OC-gA}FZ-}  
File tmpFile; //文件下载的临时信息 I:K"'R^  
DataOutputStream output; //输出到文件的输出流 WSuw
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） =UUU$hq2  
public SiteFileFetch(SiteInfoBean bean) throws IOException -f*P nxg  
{ rj(T~d4  
siteInfoBean = bean; X}+>!%W!}  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 3EJt%}V$k  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); (=7Cs  
if(tmpFile.exists ()) If\fLhM  
{ 8Z(Mvq]f&  
bFirst = false; /p8dZ
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read_nPos(); n{6G"t:^l  
} uj :%#u  
else L4!{h|  
{ JvY
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nStartPos = new long[bean.getNSplitter()]; j4qJ.i  
nEndPos = new long[bean.getNSplitter()]; |JQQU!x  
} Q~Hy%M%R3  
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} \[y`'OD~  
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public void run() zAiXo
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{ [eC2"&}  
//获得文件长度 )ubiB^g'm  
//分割文件 *s:(j
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//实例FileSplitterFetch xL\0B,]  
//启动FileSplitterFetch线程 UEguF&  
//等待子线程返回 $m/)FnU/  
try{ Q\ 0cvmU  
if(bFirst) abyo4i5T  
{ [Al&  
nFileLength = getFileSize(); b45-:mi!&#  
if(nFileLength == -1) iv4H#rJ  
{ <i&_ooX  
System.err.println("File Length is not known!"); 4rLL[??  
} z*a:L}$  
else if(nFileLength == -2) ]x(!&y:h  
{ c9&xe"v  
System.err.println("File is not access!"); ~XOTs  
} >&}%+r\  
else 0eDHu  
{ f=WDR m]  
for(int i=0;i<nStartPos.length;i++) =`H@%  
{ 67Th;h*sh  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); R8a3 1&  
} y.< m#Zzt  
for(int i=0;i<nEndPos.length-1;i++) -#N.X_F  
{ }E50>g  
nEndPos = nStartPos[i+1]; ^f4s"T  
} hvsWs.;L'  
nEndPos[nEndPos.length-1] = nFileLength; Z/Dx,zIR  
} huh6t !  
} t*1fLumXR  
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//启动子线程 rrik,qyv6  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; z`f($t[  
for(int i=0;i<nStartPos.length;i++) {#?N  
{ f'EuY17w  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), LnH?dy  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), CVL3VT1j0  
nStartPos,nEndPos,i); .$+#1-  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 5YeM%%-S  
fileSplitterFetch.start(); b*c*r dTx  
} gd`!tRcNY  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), P-yjN  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); QI'Oz{vE  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", $
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nEndPos = " + nFileLength); \fz<.l]  
// fileSplitterFetch[nPos.length-1].start(); 4%>$-($  
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< $lCkSx<Q  
//等待子线程结束 hKL4cpK4  
//int count = 0; &^}1O:8e  
//是否结束while循环 DgId_\Ze  
boolean breakWhile = false; r1 !@hT  
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while(!bStop) [+T.at  
{ i&bA2p3+d  
write_nPos(); 4i)1'{e  
Utility.sleep(500); @E7DyU|  
breakWhile = true; EE&K0<?T|:  
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for(int i=0;i<nStartPos.length;i++) x<tb  
{ .o(fe\KHf  
if(!fileSplitterFetch.bDownOver) le|~BG hL  
{ }~e8e 
 
breakWhile = false; B+P(M!m3  
break; #A1%gIw<v2  
} +%
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} ^oBtfN>4  
if(breakWhile) +h|`/ &,  
break;  VA6}  
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//count++; sBj(Qd  
//if(count>4) _mqL8ho  
// siteStop(); SYAyk  
} cLpYW7vZ[  
#xsE3Wj-X  
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System.err.println("文件下载结束！"); $v4.sl:x  
} '.IW.{;$  
catch(Exception e){e.printStackTrace ();} Vz~{UHH6  
} R1adWBD>  
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//获得文件长度 l%k\JY-  
public long getFileSize() v|XTr,#  
{ [%"|G9  
int nFileLength = -1; [L3=x;U  
try{ 'nzg6^I7g  
URL url = new URL(siteInfoBean.getSSiteURL()); 8g@<d^8@  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); a#cCpE  
httpConnection.setRequestProperty("User-Agent","NetFox"); t6bV?nc  
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int responseCode=httpConnection.getResponseCode(); Jj; L3S  
if(responseCode>=400) f%is~e~wc  
{ ],@rS9K  
processErrorCode(responseCode); ($q-_m  
return -2; //-2 represent access is error i?p$H0bn  
} m|SUV  
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String sHeader; v,FU
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for(int i=1;;i++) ]FJjgu<  
{ JrJo|0Q  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); `l\7+0W  
//Utility.log(in.readLine()); }~YA5^VQ$  
sHeader=httpConnection.getHeaderFieldKey(i); +%+tr*04O  
if(sHeader!=null) _F6OM5F"N  
{ ?h$NAL?  
if(sHeader.equals("Content-Length")) S3q&rqarC%  
{ ]0Y4U7W  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); \o z#l'z  
break; 52@C9Q,  
} H`*LBqDk  
} +^` I?1\UF  
else vNyf64)  
break; Zd3S:),&  
} .M qP_Z',  
} ]N~2 .h  
catch(IOException e){e.printStackTrace ();} h0(BO*cy  
catch(Exception e){e.printStackTrace ();} bg!/%[ {M  
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Utility.log(nFileLength); Ow+GS{-q  
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return nFileLength; Q)~aiI0  
} S8kCp;  
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//保存下载信息（文件指针位置） .e
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private void write_nPos() PIJr{6B/PA  
{ Mer/G2#&  
try{ +>8'mf  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 8+~ >E  
output.writeInt(nStartPos.length); NG=@ -eu  
for(int i=0;i<nStartPos.length;i++) -"R2  
{ -z ID x  
// output.writeLong(nPos); J!AgBF N4  
output.writeLong(fileSplitterFetch.nStartPos); TtJH7  
output.writeLong(fileSplitterFetch.nEndPos); TYy?KG>:'  
} A
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output.close(); 3$9s\<j  
} j%Y#(Q>  
catch(IOException e){e.printStackTrace ();} ?U%qPv:  
catch(Exception e){e.printStackTrace ();} '50OgF'  
} '3R`lv   
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//读取保存的下载信息（文件指针位置） zUt'QH7E.  
private void read_nPos() B |5]Jm]  
{ &9.Cl;I  
try{ zv|2:4H  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); =%BSKSG.  
int nCount = input.readInt(); Z|&MKG24  
nStartPos = new long[nCount]; Ja|5 @  
nEndPos = new long[nCount]; |O{m2Fi  
for(int i=0;i<nStartPos.length;i++) _jvxc'6  
{ RaO-H  
nStartPos = input.readLong(); !`M,XSp(  
nEndPos = input.readLong(); 4`lLf  
} /?wtF4  
input.close(); EZgq ?l~5O  
} 0XOp3  
catch(IOException e){e.printStackTrace ();} 1;JEc9#h  
catch(Exception e){e.printStackTrace ();} 
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} J9..P&c\  
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private void processErrorCode(int nErrorCode) V"[g.%%Y  
{ l?\jB\,  
System.err.println("Error Code : " + nErrorCode); 'I`&Yo~c9  
} aJSO4W)P  
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//停止文件下载 }cM}Oavh  
public void siteStop() 2\R'@L*  
{  FK^p")i  
bStop = true; m1j*mtu  
for(int i=0;i<nStartPos.length;i++) Av$]|b  
fileSplitterFetch.splitterStop(); 2d
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} t;){D:]k  
} :vYYfs&  
//负责部分文件的抓取 /hpY f]t  
**FileSplitterFetch.java N'F77 .  
*/ J;S (>c  
package NetFox;  52Yq  
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import java.io.*; BIH-"vTy  
import java.net.*; T!uM+6|Y  
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public class FileSplitterFetch extends Thread { GmK^}=frj  
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9U7nKJ+iby  
String sURL; //File URL md+nj{Ib  
long nStartPos; //File Snippet Start Position bjyZk_\  
long nEndPos; //File Snippet End Position '-wj9OU  
int nThreadID; //Thread's ID evenq$ H  
boolean bDownOver = false; //Downing is over "WlZ)wyF%  
boolean bStop = false; //Stop identical {GvJZ!,RCg  
FileAccessI fileAccessI = null; //File Access interface Ii6<b6-  
65L6:}#  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException K~uXO  
{ .nTwPrG  
this.sURL = sURL; r`$OO,W  
this.nStartPos = nStart; vjLJinJ/  
this.nEndPos = nEnd; '-QwssE  
nThreadID = id; Ltv]pH}YN  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 AJt+p&I[J  
} AW%50V  
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public void run() "Hya6k>j  
{ D{!6Y*d6&s  
while(nStartPos < nEndPos && !bStop) 1Vsz4P"O $  
{ 5
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try{ ksc;X$f&4  
URL url = new URL(sURL); PvzcEV  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); B|Du@^$  
httpConnection.setRequestProperty("User-Agent","NetFox"); ks&*O!h  
String sProperty = "bytes="+nStartPos+"-"; Yf:IKY  
httpConnection.setRequestProperty("RANGE",sProperty); ZLc -RM  
Utility.log(sProperty); 7jxs
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InputStream input = httpConnection.getInputStream(); t

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//logResponseHead(httpConnection); kh!FR u h  
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byte[] b = new byte[1024]; #[,IsEpDO1  
int nRead; l#m#c6;=  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) :=}BN  
{ &[_g6OL  
nStartPos += fileAccessI.write(b,0,nRead); v;BV@E0}x  
//if(nThreadID == 1) 6q*9[<8  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Mh~q//  
} "76]u)  
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Utility.log("Thread " + nThreadID + " is over!"); g~ZvA(`  
bDownOver = true; Q8C_9r/:N>  
//nPos = fileAccessI.write (b,0,nRead); gRrL[z  
} bT\1>  
catch(Exception e){e.printStackTrace ();} c
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} ;t'5},(FP  
} u&1q [0y  
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//打印回应的头信息 .Fs7z7?Y  
public void logResponseHead(HttpURLConnection con) m/Oh\KlIl  
{ :a^t3s  
for(int i=1;;i++) 5*E]ETo@R  
{ N6>(;ugJ1-  
String header=con.getHeaderFieldKey(i); c$ao:nP)D  
if(header!=null) gaQdG=G8$
 
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 9K
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Utility.log(header+" : "+con.getHeaderField(header)); fo5i
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else vo`2\R.  
break; ]*vdSr-J  
} t'VV>;-RO=  
} T3~k>"W  
Z LB4m`  

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public void splitterStop() j\,EO+ZQCv  
{ ?: N@!jeJ  
bStop = true; <nE>XAI_7  
} AB=daie  
--PtZ]Z  
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} &{ay=Mj  
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/* C3*gn}[  
**FileAccess.java &7<TAo;O  
*//文件访问(定位，写) 0>C T=(A  
package NetFox; h^?\xm|  
import java.io.*; EwuO&q  
UADFnwR[R  
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public class FileAccessI implements Serializable{ (mgS"zPS  
aAJU`=u
q  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ]or>?{4g  
RandomAccessFile oSavedFile; e91aK  
long nPos; i'4B3  

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{ D^{[I  
public FileAccessI() throws IOException u\ #"L  
{ 0KYEb%44  
this("",0); F5?m6`g?  
} M\sN@+  
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public FileAccessI(String sName,long nPos) throws IOException y<HO:kZ8`  
{ G"\`r* O  
oSavedFile = new RandomAccessFile(sName,"rw"); f%Ns[S~r  
this.nPos = nPos; M*z~gOZ  
oSavedFile.seek(nPos); 74H)|Dkx  
} #N#
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public synchronized int write(byte[] b,int nStart,int nLen) [K9'<Qnu  
{ M:-.o  
int n = -1; s>0't  
try{ x97 j  
oSavedFile.write(b,nStart,nLen); p;._HJ(  
n = nLen; *+-}P|S:  
} e<
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catch(IOException e) ]%|GmtqZs,  
{ v5By:z  
e.printStackTrace (); K<pV  
} vY%d  
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x  
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return n; MZlk0o2  
} cc#gEm)3C  
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} ? i( %  
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z  
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/* A3|Dz&@:  
**SiteInfoBean.java G>wqt@%r9  
*/ (@t(?Js  
package NetFox; RnhL< Ywu  
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public class SiteInfoBean { >+
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}*lUah,@  
oN{Z+T :  
private String sSiteURL; //Site's URL 11<Qxu$rL  
private String sFilePath; //Saved File's Path I3,= 0z  
private String sFileName; //Saved File's Name /G5d|P  
private int nSplitter; //Count of Splited Downloading File $/.zm;D  
h&`e) a>+  
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public SiteInfoBean() y>72{  
{//nSplitter的缺省值为5 | \'rP_I>  
//default value of nSplitter is 5 Ytz)d/3T  
this("","","",5); VwOW=4`6  
} #;%JT   
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) BO~PT,QrF  
{ l~6?kFy9h  
sSiteURL= sURL; +RnkJ* l  
sFilePath = sPath; ]@uE#a:[  
sFileName = sName; A-4h  
this.nSplitter = nSpiltter; mf}O-Igte  
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} AgFVv5  
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public String getSSiteURL() 5m9*85Ib  
{ -C<zF`jO  
return sSiteURL; .Fnwm}  
} &_"]5/"(  
.G+Pe'4a  
h\nI!{A0  
public void setSSiteURL(String value) 2 !At2P2  
{ wi4=OU1L)a  
sSiteURL = value; O2BW6Wc  
} :_t}QP"  
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public String getSFilePath() rFC" Jx  
{ co9 .wB@  
return sFilePath; 9nH?l{As  
} `;)\u  
r=6v`)Qr  
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public void setSFilePath(String value) 'A:x/iv}^  
{ cZT({uYGL  
sFilePath = value; s1e:v+B]  
} #/I[Jqf  
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public String getSFileName() PJ2qfYsH=>  
{ $d
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return sFileName; v>
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} e0J6Ae4V[  
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public void setSFileName(String value) 7f~Sf  
{ Z7RiPSdxp  
sFileName = value; ?}m']4p  
} ,}:G\u*Fu  
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04*6(L)h*  
public int getNSplitter() (sQr X{~  
{ \#rI
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return nSplitter; {'AWZ(  
} >-O/U5<!  
i| ZceX/  
kWNV%RlSx  
public void setNSplitter(int nCount) !YP@m~  
{ 0 s70r  
nSplitter = nCount; |QMhMGjV  
} 4WE6fJ2X  
} > ]8a3x  
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/* (I@rLvZr{  
**Utility.java V13BB44  
*/ Vur bW=~g  
package NetFox; =i(?deR  
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public class Utility { EaWS. eK  
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public Utility() 9{$'S4  
{ B}eA\O4}I  
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} 9W8]8sUeG  
3( ]M{4j  
//线程睡眠 !=y]Sv~h  
public static void sleep(int nSecond) Ed:eGm }  
{ IJJ%$%F/  
try{ @&"Pci+-|  
Thread.sleep(nSecond); 8v7
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} TI !a)X  
catch(Exception e) {>"
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{ 8`b`QtGf  
e.printStackTrace (); ^0#;YOk  
} /1 RAAa  
} 3b YCOqG  
!J=sk4T  
//日志 \@>b;4Fb+N  
public static void log(String sMsg) :iiw3#]  
{ =0- $W5E  
System.err.println(sMsg); #eN{!Niy&U  
} ql GW.jY.  
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public static void log(int sMsg) 2Sq_Tw3^  
{ uHIiH@S  
System.err.println(sMsg); TM8=U-A  
} b7/AnSR~Jt  
} }P3tn  
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/* )>7%pz  
**TestMethod.java `p'Q7m2y/b  
*/ u4"SH(  
package NetFox; x"4} isp<  
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kGkA:g:  
public class TestMethod { y{9~
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nJ?^?M'F%  
public TestMethod() 1ZJQs6  
{ ///xx/weblogic60b2_win.exe =TP( UJ  
try{ IkzTJ%>  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); fnCItK~y  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); !TAp+b  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 8wH.et25k  
fileFetch.start(); {m8+Wju}  
} U Q@7n1  
catch(Exception e){e.printStackTrace ();} h5kPn~  
m6
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} qP!P +'B  
~Cc.cce5  
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public static void main(String[] args) ?@6/Alk  
{ @OV-KT[>  
new TestMethod(); "tS'b+SJ-S  
} W2-=U@  
} V2|3i}V"  
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