http断点续传简单实现（java)

/* qC;1ND  
**SiteFileFetch.java Kx[u9MD  
*/ wE*jN~  
package NetFox; ;3 |Z}P  
import java.io.*; "B9aJo  
import java.net.*; _pM~v>~*+  
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public class SiteFileFetch extends Thread { !rwe|"8m?u  
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SiteInfoBean siteInfoBean = null; //文件信息Bean y;1 'hP&  
long[] nStartPos; //开始位置 s'Op|`&X  
long[] nEndPos; //结束位置 oI/jGyY;  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 LEJ8 .z6$  
long nFileLength; //文件长度 9"%ot=)  
boolean bFirst = true; //是否第一次取文件 ;uK">L[u'  
boolean bStop = false; //停止标志 nGvWlx  
File tmpFile; //文件下载的临时信息 `EjPy>kM  
DataOutputStream output; //输出到文件的输出流 Fy!-1N9|l  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） :fW\!o8Z2  
public SiteFileFetch(SiteInfoBean bean) throws IOException c/bIt  
{ N9s ,..  
siteInfoBean = bean; H|]~(.w 1}  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); XNm%O  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); J#L"kz  
if(tmpFile.exists ()) M1sR+e$"  
{ K$K6,54y  
bFirst = false; &1k2J   
read_nPos(); Pn;Tg7oz  
} R,'` A.Kk  
else GNI
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{ _#2AdhCu  
nStartPos = new long[bean.getNSplitter()]; Q,1TD2)h  
nEndPos = new long[bean.getNSplitter()]; 9N?BWv}  
} DQ a0S7I  
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{8YNmxF#  
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} 2G4OK7x  
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public void run() 'Itsu~fza  
{ /6$8djw  
//获得文件长度 `!t+sX-n  
//分割文件 v o9Fj  
//实例FileSplitterFetch O_n) 2t(c?  
//启动FileSplitterFetch线程 acXB vs  
//等待子线程返回 `QIYnokL  
try{ w&F/P]1  
if(bFirst) |D ?}6z  
{ ) C?emTih  
nFileLength = getFileSize(); :
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if(nFileLength == -1) HRPNZ!B  
{ h9B^U?<wT  
System.err.println("File Length is not known!"); "AAzBWd/  
} qxR7;/@j)  
else if(nFileLength == -2) :W++`f&  
{ 0i4X,oHjG  
System.err.println("File is not access!"); ?'I[[KuG  
} i5QG_^X&  
else ebuR-9  
{ Ki"o0u  
for(int i=0;i<nStartPos.length;i++) $xWebz0  
{ e{8j(` (;#  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 9w%|Nk>=>  
} X9d~r_2&m<  
for(int i=0;i<nEndPos.length-1;i++) /61P`1y(J  
{ f"8!uE*;  
nEndPos = nStartPos[i+1]; JDIQpO"Qji  
} &$!'Cw`,  
nEndPos[nEndPos.length-1] = nFileLength; J#pl7q)^w  
} ~BSE8M+r  
} n<. T6  
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//启动子线程 kCq]#e~wq  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; &vy/Vd  
for(int i=0;i<nStartPos.length;i++) )Apg  
{ 8\85Wk{b  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), [ NSsT>C  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), X)tf3M {J@  
nStartPos,nEndPos,i); \U1fUrw$*  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); s /?&H-  
fileSplitterFetch.start(); cP4K9:k  
} )AX0x1I|E  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), PhS`,I^Z  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); NVTNjDF%s  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", cvf@B_iN9  
nEndPos = " + nFileLength); YRkp(}*!\  
// fileSplitterFetch[nPos.length-1].start(); $SP*hkU  
]T3dZ`-(  
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//等待子线程结束 J5J$qCJq  
//int count = 0; k]vrqjn Q  
//是否结束while循环 jmcb-=ts  
boolean breakWhile = false; Or0
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 QTN _Z#'  
while(!bStop) '}`|
QJ  
{ V ifQ@  
write_nPos(); R"au8f.  
Utility.sleep(500); 2hjR'6h"Y  
breakWhile = true; 1D,$Az~.  
^Ms)T3dM  
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for(int i=0;i<nStartPos.length;i++) S<
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{ "iCR68e  
if(!fileSplitterFetch.bDownOver) ]m#.MZe  
{ J|orvnkK  
breakWhile = false; 09f:%!^u  
break; Al^n&Aa+\  
} 7VF^&6  
} yMQuM:d  
if(breakWhile) H?dmNwkPY  
break; /ry#q%?  
6~ *w~U  
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//count++; VtR?/+8X  
//if(count>4) 5a
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// siteStop(); KP
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} `Z3Qx~fx  
CvCk#:@HM  
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System.err.println("文件下载结束！"); YU89m7cc'  
} ZWC-<QO"<  
catch(Exception e){e.printStackTrace ();} 6,"fH{Bd  
} ^lqcF.  
AxaabS$\  
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//获得文件长度 Xwg|fr+p  
public long getFileSize() iY=M67V  
{ lWv3c!E`  
int nFileLength = -1; _]"5]c&*3  
try{ 'L*nC T;  
URL url = new URL(siteInfoBean.getSSiteURL()); OIF0X!  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); &&0,;r,-)  
httpConnection.setRequestProperty("User-Agent","NetFox"); FuOP+r!H  
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int responseCode=httpConnection.getResponseCode(); ?|8QL9Q"|  
if(responseCode>=400) dOm#NSJVd  
{ f`5e0;zm  
processErrorCode(responseCode); vG(Gs=.U  
return -2; //-2 represent access is error iOB]72dh  
} }+[H~8)5  
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String sHeader; ^A8'YTl  
Ni5~Buf  
la ~T)U7  
for(int i=1;;i++) pV#~$e  
{ ?_e2)+q8YG  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Y[A
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//Utility.log(in.readLine()); tJ>OZ  
sHeader=httpConnection.getHeaderFieldKey(i); v;S7i>\  
if(sHeader!=null) G<kslTPyq  
{ r
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if(sHeader.equals("Content-Length")) JM5w`=  
{ p
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nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 1 l'Wb2g>A  
break; %nJ^0X_]  
} t[B\'f!  
} aU]A#g   
else r5qp[Ss3F  
break; NymS8hxR  
} k zhek >  
} x+zz:^yHYf  
catch(IOException e){e.printStackTrace ();} esH>NH_  
catch(Exception e){e.printStackTrace ();} nXDU8|"  
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Utility.log(nFileLength); 5Sd+Cc  
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return nFileLength; +#gJ[Cc  
} +'abAST t  
:\x)
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//保存下载信息（文件指针位置） +tL]qOBP  
private void write_nPos() 8\m_.e  
{ d`LBFH,  
try{ .jRp.U  
output = new DataOutputStream(new FileOutputStream(tmpFile)); etdI:N*x  
output.writeInt(nStartPos.length); UQ#"^`=R<  
for(int i=0;i<nStartPos.length;i++) ql5NSQ>{  
{ sE$!MQb  
// output.writeLong(nPos); sQrP,:=r#  
output.writeLong(fileSplitterFetch.nStartPos); D 8^wR{-;J  
output.writeLong(fileSplitterFetch.nEndPos); A4.Q\0  
} WJ$D]7  
output.close(); * B!uYP  
} YC#N],#  
catch(IOException e){e.printStackTrace ();} j 
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catch(Exception e){e.printStackTrace ();} +E7s[9/r  
} w-?_U7'  
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4l+"J:,  
//读取保存的下载信息（文件指针位置） V6Kw71'9  
private void read_nPos() oLEqy  
{ m72r6Yq2@  
try{ 53d8AJ_@X  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Qvh:
hkR  
int nCount = input.readInt(); v*'dA^Q  
nStartPos = new long[nCount]; S6gg(nNe  
nEndPos = new long[nCount]; bX%9'O[-  
for(int i=0;i<nStartPos.length;i++) :T(3!}4  
{ H8+7rM  
nStartPos = input.readLong(); /t`s.!k  
nEndPos = input.readLong(); dieGLA<5_X  
} l
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input.close(); MXsSF|-  
} N;ed_!  
catch(IOException e){e.printStackTrace ();} b f.__3{  
catch(Exception e){e.printStackTrace ();} 5LU8QHj3  
} d^sS{m\  
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private void processErrorCode(int nErrorCode) )IQa]A  
{ A{mv[x-XN  
System.err.println("Error Code : " + nErrorCode); BtS#I[-p_  
} bhaIi>W~G  
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\
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//停止文件下载 4$LVl  
public void siteStop() G9ku(2cq  
{ +CL`]'~;E-  
bStop = true; BwwOaO@L  
for(int i=0;i<nStartPos.length;i++) SW|{)L,  
fileSplitterFetch.splitterStop(); 25%[nkO4  
[F4]pR(  
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} CAdqoCz|  
} S%zn
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//负责部分文件的抓取 T9.3  
**FileSplitterFetch.java $eUI.j(HU  
*/ c8!q_H~  
package NetFox; T:&  
Eb66GXF[  
o.IJ4'}aN  
import java.io.*; c3,YA,skb!  
import java.net.*; 4SRX@/ #8*  
R&Y+x;({  
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public class FileSplitterFetch extends Thread { 7}>7@W8  
`R@1Sc<*|  
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String sURL; //File URL ^$-ID6  
long nStartPos; //File Snippet Start Position 9?$Qk0jc  
long nEndPos; //File Snippet End Position 3oX\q/$  
int nThreadID; //Thread's ID <7-:flQz~  
boolean bDownOver = false; //Downing is over X6I"&yct  
boolean bStop = false; //Stop identical "NR`{1f:O  
FileAccessI fileAccessI = null; //File Access interface *@`Sx'5!  
Fd!Np7xw  
D4nYyj1O3  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException qKu/~0a/  
{ A)"?GK{*  
this.sURL = sURL; PhTMXv<cE  
this.nStartPos = nStart; J?VMQTa/+  
this.nEndPos = nEnd; /U\k<\1~m  
nThreadID = id; s`Z| A  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 S"+X+Oxp7?  
} jroR2*  
2wR?ON=Q  
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public void run() )5n*4A  
{ V0 70o
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while(nStartPos < nEndPos && !bStop) BN??3F8C  
{ s6=jHrdvv  
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oPP`)b$x  
try{ G
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URL url = new URL(sURL); 66ULR&D8  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); M&auA  
httpConnection.setRequestProperty("User-Agent","NetFox"); fCC^hB]'  
String sProperty = "bytes="+nStartPos+"-";
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httpConnection.setRequestProperty("RANGE",sProperty); X0a)6HZ{  
Utility.log(sProperty); 8SH&b8k<<  

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InputStream input = httpConnection.getInputStream(); H!N`hEEj>  
//logResponseHead(httpConnection); m5i?<Ko@  
'x/pV5[hQ  
KV&4Ep#  
byte[] b = new byte[1024]; 7dxTyn=  
int nRead; zsM3 [2E*  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) D@.+B`bA  
{ ~)ut"4  
nStartPos += fileAccessI.write(b,0,nRead); >~_oSC)E
 
//if(nThreadID == 1) {\:"OcP #  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); r xlKoa  
} T,G38  
)>-94xx|  
-d'swx2aZ!  
Utility.log("Thread " + nThreadID + " is over!"); [%?ViKW  
bDownOver = true; R3 Zg,YM  
//nPos = fileAccessI.write (b,0,nRead); 3+:F2sjt  
} s>pM+PoGYd  
catch(Exception e){e.printStackTrace ();} ^HiI
   
} hB[VU ";  
} |azdFf6A:[  
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r@WfZZ  
//打印回应的头信息 `I
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public void logResponseHead(HttpURLConnection con) 2Q bCH}  
{ N$&)gI:  
for(int i=1;;i++) W"3YA+qpI  
{ u7>{#]  
String header=con.getHeaderFieldKey(i); Uw!N;QsC  
if(header!=null) kH4xP3. i  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); UO~Xzx!e  
Utility.log(header+" : "+con.getHeaderField(header)); /9QC$Z):<  
else /&>vhpZ}  
break; X0FTD':f  
} *OM+d$l!  
} OdSglB  
8bTE#2+-  
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public void splitterStop() b
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{ AQ)DiH  
bStop = true; 1\u{1 V  
} q0sdL86  
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2=]Xe#5J=  
} [H4)p ,R  
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tDWoQ&z2t_  
/* P >>VBh?  
**FileAccess.java UI]UxEJ  
*//文件访问(定位，写) ?GT,Y5  
package NetFox; b fj]Q  
import java.io.*; q+ZN$4m  
OyG#
 
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public class FileAccessI implements Serializable{ xq@_' 3X  
G4<M@ET  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 S4O'N x  
RandomAccessFile oSavedFile; fUKi@*^ZUa  
long nPos; oVAY}q|wU  
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1`q>*S](  
public FileAccessI() throws IOException +3d.JQoKl  
{ =zsA@UM0  
this("",0); O[<YYL0  
} O'.sK pXe  
%=*nJvYS  
*]K/8MbiF  
public FileAccessI(String sName,long nPos) throws IOException JqTR4[`Z\  
{ Dkyw3*LCn%  
oSavedFile = new RandomAccessFile(sName,"rw"); ;N?raz2mEi  
this.nPos = nPos;  8?4/  
oSavedFile.seek(nPos); -Cc2|~n  
} :ceT8-PBRx  
Va-.  
1e)5D& njS  
public synchronized int write(byte[] b,int nStart,int nLen) -qs R,H  
{ L"[>tY  
int n = -1; 3uy^o  
try{ 0 zn }l6OS  
oSavedFile.write(b,nStart,nLen); qe_qag9  
n = nLen; {oVoN>gp  
} Qj3l>O
 
catch(IOException e) =N^j:t  
{ U UY
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e.printStackTrace (); /cC4K\M  
} H[J5A2b  
., =\/ C<  
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return n; .|c=]_{  
} *-,jIaL;  
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} njGZ#{"eC  
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8S#TOeQ  
/* S%IhpTSe6  
**SiteInfoBean.java VlFhfOR6
t  
*/ s$ZKd  
package NetFox; neBc
S[  
qBF}-N_  
hOM#j  
public class SiteInfoBean { J/>9
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["BD,mB  
Xf%wW[~  
private String sSiteURL; //Site's URL ojbms>a  
private String sFilePath; //Saved File's Path i~ITRi@  
private String sFileName; //Saved File's Name m ?#WQf  
private int nSplitter; //Count of Splited Downloading File Jq8:33s  
z;lWr(-x  
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public SiteInfoBean() /#Lm)-%G  
{//nSplitter的缺省值为5 Sej(jJX1  
//default value of nSplitter is 5
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this("","","",5); &'"dYZj{  
} $TY1'#1U;  
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w\%AR1,rs  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) F-GrQd:O=  
{ 8c<OX!  
sSiteURL= sURL; Noi+mL  
sFilePath = sPath; z+{Q(8'b]  
sFileName = sName;
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this.nSplitter = nSpiltter; V*%Lc9<d  
r68d\N`.  
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} 3Bbd2[<W  
4;)aGN{e  
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public String getSSiteURL() NxrfRhaU3  
{ 3Q2z+`x'  
return sSiteURL; TQ69O +  
} .9$ 7 +  
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public void setSSiteURL(String value) ueLdjASJ  
{ >vZ^D  
sSiteURL = value; {O5(O oDa  
} c;doxNd6  
R=<uf:ca  
G~{#%i  
public String getSFilePath() @ayrI]m#>,  
{ Z ItS(oJ.  
return sFilePath; -m_H]<lWZ  
} 8^5@J)R8  
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public void setSFilePath(String value) zc&i 4K  
{ u$ a7  
sFilePath = value; ';KZ.D  
} !Nx'4N`&l  
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Ak+MREG  
public String getSFileName() g&fq)d  
{ <4RP:2#  
return sFileName;
sG:tyvln  
} A ^X1  
H'x)[2  
Q)93+1]  
public void setSFileName(String value) W3]?>sLE*  
{ 6GsB*hW  
sFileName = value; 2<TpNGXM_  
} U$EQeb  
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public int getNSplitter() >L,Pw1Y0W[  
{ VdF<#(
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return nSplitter; 25/M2u?  
} ?;ovh nY)  
4rH:`494  
F+285JK  
public void setNSplitter(int nCount) U^d!*9R  
{ bI+ TFOP  
nSplitter = nCount; [f#7~  
} (x1 #_~  
} hs?cV)hDS  
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/* s E0ldN"  
**Utility.java /5j]laYK)  
*/ a4x(lx&  
package NetFox; `c/mmS  
fB`7f $[  
o>@9[F,h+  
public class Utility { U%l<48@8  
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public Utility() A?ij  
{ !"s~dL,7  
D |9ItxYu  
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} Bw4 _hlm  
'WcP+4c  
//线程睡眠 Z l
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public static void sleep(int nSecond) CNrK]+>  
{ -(l/.yE{X  
try{ p[:E$#W~;  
Thread.sleep(nSecond); {/q4W; D  
} G&dz<f
 
catch(Exception e) vl:V?-sY  
{ k_](u91  
e.printStackTrace (); Gp}}MGk  
} z1m$8-4  
} Ue!~|:  
#Y<(7  
//日志 TRku(w1f  
public static void log(String sMsg) N\W
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{ 4<q'QU#l<  
System.err.println(sMsg); gYW  
} TUM7(-,9  
ZGC*BP/  
3#~w#Q0%  
public static void log(int sMsg) +JPHQx'W  
{ f~v@;/HL  
System.err.println(sMsg); nW!pOTJq21  
} &ngG_y8}&  
} (VB-5&b  
NG\^>.8  
">!<OB  
/* o 76QQ+hP  
**TestMethod.java F92et<y.  
*/ 4NRG{FZ9  
package NetFox; F8>J(7On  
K&UTs$_cI  
$pfN0/`(  
public class TestMethod { Z{rD4S@^  
,Ep41v;T%`  
8 CCA}lOG  
public TestMethod() v)-:0f  
{ ///xx/weblogic60b2_win.exe y4`uU1=  
try{ )~=g}&  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); N^xk.O_TO  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); AlhPT (  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ~WX40z  
fileFetch.start(); 2pV@CT  
} ]2@g 5H}M  
catch(Exception e){e.printStackTrace ();} 3p#BEH<re  
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hp!. P1b  
} ]97`=,OUg  
'X/(M<c  
7MhN>a;A\  
public static void main(String[] args) CZ}%\2>-v  
{ V jZx{1kCR  
new TestMethod(); Fv2U@n6'v  
} I'a&n}jx  
} O+*<^*YyD  
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