http断点续传简单实现（java)

/* ""{|3XJe  
**SiteFileFetch.java -h#mn2U~3r  
*/ y#v"GblM  
package NetFox; <YFY{VC(  
import java.io.*; 6_gnEve h  
import java.net.*; 15{Y9
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; |L<:x/  
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public class SiteFileFetch extends Thread { g> S*<  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 8i}< k$S  
long[] nStartPos; //开始位置 GX&b;N  
long[] nEndPos; //结束位置  U4
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FileSplitterFetch[] fileSplitterFetch; //子线程对象 vyI%3+N@  
long nFileLength; //文件长度 ,RxYd6  
boolean bFirst = true; //是否第一次取文件 d2S~)/@S  
boolean bStop = false; //停止标志 VR5fqf|*  
File tmpFile; //文件下载的临时信息 (*\jbK
 
DataOutputStream output; //输出到文件的输出流 i)ASsYG!  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） in-C/m#  
public SiteFileFetch(SiteInfoBean bean) throws IOException hWo=;#B*  
{ ]3Dl)[R   
siteInfoBean = bean; LfLFu9#:w  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ;heHefbvvd  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); x;\wY'  
if(tmpFile.exists ()) 28andfl  
{ X|DO~{-au  
bFirst = false; fNu'((J-  
read_nPos(); /mM2M-  
} ?!VIS>C(  
else v$wBxCY  
{ q<#>HjC  
nStartPos = new long[bean.getNSplitter()]; 2F`cv1M  
nEndPos = new long[bean.getNSplitter()]; FG@-bV  
} !xIm2+:(  
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}
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public void run() !0,Mp@ j/  
{ ,TJD$^  
//获得文件长度 ;z~n.0'  
//分割文件 nqVZqX@oE  
//实例FileSplitterFetch kcie}Be  
//启动FileSplitterFetch线程 =*vM
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//等待子线程返回 2[fN\e{  
try{ MZJ]Dwt]  
if(bFirst) &w8)* T  
{ Wu6<\^A  
nFileLength = getFileSize(); $,>@o=)_  
if(nFileLength == -1) b6(p  
{ ]iNEw9  
System.err.println("File Length is not known!"); -62'}%?A<C  
} eP.Vd7ky  
else if(nFileLength == -2) qFQ8  
{ NS)}6OI3~"  
System.err.println("File is not access!"); 6$fYt&1  
} &k7;DO  
else 4)>FS'=  
{ KInk^`C/H  
for(int i=0;i<nStartPos.length;i++) y! .J  
{ jjM\.KL]  
nStartPos = (long)(i*(nFileLength/nStartPos.length));
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} C[!MS5  
for(int i=0;i<nEndPos.length-1;i++) wCf~O'XLw  
{ {O<l[|Ip  
nEndPos = nStartPos[i+1]; C:8_m1Y{  
} c#IYFTz  
nEndPos[nEndPos.length-1] = nFileLength; b1XRC`Gy  
} r|e-<t4.9L  
} D]a<4a18  
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//启动子线程 D?yG+%&9  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; |t iUej  
for(int i=0;i<nStartPos.length;i++) &N~ZI*^  
{ C;QAT  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), jn >d*9u  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ^.k |SK`U  
nStartPos,nEndPos,i); BBG3OAyg_  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Io4(f  
fileSplitterFetch.start(); @yXfBML?]  
} ofYlR
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// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), p Dx-2:}  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); e!Y0-=?nf#  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", B+C);WQ,  
nEndPos = " + nFileLength); 8}X5o]Mv  
// fileSplitterFetch[nPos.length-1].start(); uXDq~`S  
g,o?q:FL  
'0y9MXRT  
//等待子线程结束 "<_0A f]  
//int count = 0; iRg7*MQu  
//是否结束while循环 =[\s8XH,  
boolean breakWhile = false; DypFl M*  
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while(!bStop) :ISMPe3'  
{ r78TE@d  
write_nPos(); P0H6mn*  
Utility.sleep(500); b"!Q2S~  
breakWhile = true; "YdEE\  
8:BIbmtt5  
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for(int i=0;i<nStartPos.length;i++) w.,Q1\*rPp  
{ Le<wR  
if(!fileSplitterFetch.bDownOver) :1t~[-h^  
{ 3d<HN6&U  
breakWhile = false; L-B<nl  
break; M?&h~V1OI~  
} %sHF-n5P  
} / XnhmqWm%  
if(breakWhile) qd8n2f  
break; ?bM_q_5  
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//count++; _k8A$s<d  
//if(count>4) ebPgYxVZR  
// siteStop(); iyj+:t/  
} ?4H i-  
it]E-^2>  
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System.err.println("文件下载结束！"); |FD}e)  
} 5_XV%-wM  
catch(Exception e){e.printStackTrace ();} xss`Y,5?  
} !mWiYpbU+  
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//获得文件长度 f2,jh}4  
public long getFileSize() >pU:Gr  
{ *@d&5  
int nFileLength = -1; EkGQ(fZ1|  
try{ #2r}?hP/m  
URL url = new URL(siteInfoBean.getSSiteURL());  /'31w9  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); +w=AJdc  
httpConnection.setRequestProperty("User-Agent","NetFox"); o9cM{ya/>  
5M9 I,  
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int responseCode=httpConnection.getResponseCode(); DjSbyXvrg  
if(responseCode>=400) 'v]u#/7a  
{ U|g:`v7  
processErrorCode(responseCode); sdQkT#%y  
return -2; //-2 represent access is error A^q[N  
} j"AU z)x  
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String sHeader; nLV9<M Zm  
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for(int i=1;;i++) L%>n>w  
{ R(n^)^?  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); =gcM%=*'  
//Utility.log(in.readLine()); lFTF ,G  
sHeader=httpConnection.getHeaderFieldKey(i); o] mD
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if(sHeader!=null) 2h[85\4  
{ x3PD1JUf  
if(sHeader.equals("Content-Length")) YZ%Hu)  
{ J>u
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nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); {uGP&c
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break; 6oF7:lt  
} Ok n(pJ0  
} 2Ry1b+\  
else 5Ri6Z#qm  
break; F <hJp,q9  
} kWdi595  
} vDH>H^9Y  
catch(IOException e){e.printStackTrace ();} qhT@;W/X  
catch(Exception e){e.printStackTrace ();} k?2k'2dy  
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Utility.log(nFileLength); i\W/C  
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return nFileLength; C+|b1/N-  
} Yv:55+e!|  
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~#kT_*sw)  
//保存下载信息（文件指针位置） _x!7}O#k  
private void write_nPos() QR1{ w'c  
{ d>{nQF;c  
try{ 44-
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output = new DataOutputStream(new FileOutputStream(tmpFile)); <vXGi  
output.writeInt(nStartPos.length); 8P=o4lO+  
for(int i=0;i<nStartPos.length;i++) gks{\H]  
{ CZ nOui  
// output.writeLong(nPos); $z+8<?YD  
output.writeLong(fileSplitterFetch.nStartPos); b, :QT~g=  
output.writeLong(fileSplitterFetch.nEndPos); `F/Tv 5@L  
} yz0zFfiX  
output.close(); A<W6=5h  
} 6 ~>FYX  
catch(IOException e){e.printStackTrace ();} e^O(e  
catch(Exception e){e.printStackTrace ();} 3Kn_mL3V-  
} f]`vRvbe  
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//读取保存的下载信息（文件指针位置） qG<$Ajiin  
private void read_nPos() &gjF4~W]  
{ T8^5=/  
try{ < P`u}  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 7U"[Gf  
int nCount = input.readInt(); ",!1m7[wF  
nStartPos = new long[nCount]; 4fe7U=#;Y  
nEndPos = new long[nCount]; Fy.\7CL>  
for(int i=0;i<nStartPos.length;i++) %JLk$sP9y`  
{ y
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nStartPos = input.readLong(); !%c'$f/  
nEndPos = input.readLong(); `\+@Fwfx  
} ~V$|i"  
input.close(); Kw#i),M  
} 7^g&)P  
catch(IOException e){e.printStackTrace ();} Aj0Tfdxy  
catch(Exception e){e.printStackTrace ();} Ps 8%J;  
} CP6LHkM9  
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private void processErrorCode(int nErrorCode) n/h,Lr)Z  
{ %?m$`9yU  
System.err.println("Error Code : " + nErrorCode); HQB(*  
} 8H_l:Z[:i  
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8HP6+c%  
//停止文件下载 6,9o>zT%H  
public void siteStop() ~j<+k4I~  
{ 3"P }n  
bStop = true; Yh>]-SCw  
for(int i=0;i<nStartPos.length;i++) 1CHeufQ  
fileSplitterFetch.splitterStop(); Ry|!p
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} xe*aC  
} ak;*W  
//负责部分文件的抓取 A]DTUdL  
**FileSplitterFetch.java 4)("v-p  
*/ !=N"vD*  
package NetFox; *guoWPA|Ij  
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import java.io.*; YJo["Q  
import java.net.*; E>}4$q[r  
t1%_DPD%W  
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public class FileSplitterFetch extends Thread { +Xemf?  
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String sURL; //File URL )4&cph';  
long nStartPos; //File Snippet Start Position ~t~-A,1  
long nEndPos; //File Snippet End Position oIefw:FE,a  
int nThreadID; //Thread's ID WH= EPOR,  
boolean bDownOver = false; //Downing is over u&n' ITH  
boolean bStop = false; //Stop identical uh?>- ]r`  
FileAccessI fileAccessI = null; //File Access interface }6@pJG  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Q*b]_0Rb  
{ w.0qp)}  
this.sURL = sURL; D)d~3`=#  
this.nStartPos = nStart; >>5NX"{  
this.nEndPos = nEnd; WASU0
 
nThreadID = id; (t4&,W_spA  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 +9")KQT  
} ~SnSEhE  
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public void run() QI3Nc8t_2  
{ 1[yq0^\]M[  
while(nStartPos < nEndPos && !bStop) ('hEr~&  
{ $t6e2=7  
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try{ m`FNIY  
URL url = new URL(sURL); /,!B2  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); kJ Mf  
httpConnection.setRequestProperty("User-Agent","NetFox"); Ba/Yl  
String sProperty = "bytes="+nStartPos+"-"; g2T -TG'd  
httpConnection.setRequestProperty("RANGE",sProperty); [!U?}1YQ  
Utility.log(sProperty); .;*s`t  
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InputStream input = httpConnection.getInputStream(); .3MIcj=p  
//logResponseHead(httpConnection); ,Y>Bex_v  
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byte[] b = new byte[1024]; r9ww.PpNk#  
int nRead; "1HRLci  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) k+DR]icv  
{ 'FS?a  
nStartPos += fileAccessI.write(b,0,nRead); gR}35:$Z-  
//if(nThreadID == 1) 1)[]x9]^q'  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); G3{=@Z1  
} 
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Utility.log("Thread " + nThreadID + " is over!"); T9879[ZU\  
bDownOver = true; >G~R,{6U  
//nPos = fileAccessI.write (b,0,nRead);  ,qYJioWX  
} eR3$i)5  
catch(Exception e){e.printStackTrace ();} ryFxn|4  
} ti<;7Yb  
} f0BdXsV#g  
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//打印回应的头信息 Z%n(O(^L  
public void logResponseHead(HttpURLConnection con) ZE/o?4k*c1  
{ FTeu~<KpM  
for(int i=1;;i++) $O*O/iG  
{ xQp|;oW;z  
String header=con.getHeaderFieldKey(i); ]hbyELs  
if(header!=null) ._+J_ts  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); -G|G_$9  
Utility.log(header+" : "+con.getHeaderField(header)); /0eYMG+K=  
else rQaxr!  
break; 37RLE1Yf  
} "|HDGA5  
} HuVJ\%.  
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public void splitterStop() 7ek&[SJ>,/  
{ MG{YrX)oi  
bStop = true;
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} m,t|IgDh  
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} + Q6l*:<|c  
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/* :,DM*zBVp  
**FileAccess.java Q pmsOp|  
*//文件访问(定位，写) E=#0I]v[  
package NetFox; %bdjBa}  
import java.io.*; (~J^3O]Fo  
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public class FileAccessI implements Serializable{ nQ/E5y  
25&J7\P*  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 |eWjYGwJa  
RandomAccessFile oSavedFile; l#}.^71+  
long nPos; SC- $B  
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public FileAccessI() throws IOException KW7UUXL  
{ cDI [PJ9  
this("",0); c?%(DpE  
} LvEnXS  
]]"jw{W}A  
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public FileAccessI(String sName,long nPos) throws IOException Z?O*'#yn  
{ {b@KYR9K  
oSavedFile = new RandomAccessFile(sName,"rw"); G
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this.nPos = nPos; np4+"  
oSavedFile.seek(nPos); =?-ye!w  
} IO/4.m-aN#  
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}`NU@O#  
public synchronized int write(byte[] b,int nStart,int nLen) kVD(Q~<  
{ %G?;!Lz  
int n = -1; ;q1A*f\:#  
try{ .m`y><.5  
oSavedFile.write(b,nStart,nLen); kMsnW}Nu  
n = nLen; ymNnkFv  
} NVl [kw  
catch(IOException e) zR32PG>9  
{ yu;SH[{Wi  
e.printStackTrace (); _kY#D;`:r  
} W.w)H@]7m  
sQ8s7l0D  
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return n; E[^ {w  
} mB0l "# F  
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} %xQ
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/* X@|&c]]  
**SiteInfoBean.java d O~O |Xsb  
*/ fkSwD(  
package NetFox; ILic.@st  
GAc{l=vT'  
1HPx|nmE]  
public class SiteInfoBean { u@3y&b  
A?*o0I  
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private String sSiteURL; //Site's URL d;+[i  
private String sFilePath; //Saved File's Path o#[ KS:Y  
private String sFileName; //Saved File's Name Q_vW3xz  
private int nSplitter; //Count of Splited Downloading File U #~;)fZ  
:>81BuMvg  
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public SiteInfoBean() H-p
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{//nSplitter的缺省值为5 K)_WL]RJ.4  
//default value of nSplitter is 5 9V.u-^o&  
this("","","",5); \`w4|T  
} u(!&:A9JFd  
oW;6h.  
]LZ`LL'#Y_  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) emW:C-/h/@  
{ v~/~@jv  
sSiteURL= sURL; d HJhFw  
sFilePath = sPath; 9*:gr#(5  
sFileName = sName; (7DXRcr<  
this.nSplitter = nSpiltter; 5ZY)nelc  
-<#!DjV6(  
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} =KT7nl  
.6~`Ubr}E  
1w"8~Z:UXV  
public String getSSiteURL() g`>og^7g  
{ _Zc%z@}  
return sSiteURL; vEG'HOP  
} fKtV'/X;Q  
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HWm#t./  
public void setSSiteURL(String value) syzdd an  
{ 4"=Vq5  
sSiteURL = value; _3Cn{{ A0  
} U,Mx@KdV  
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public String getSFilePath() ?U7) XvQ  
{ aTzDew  
return sFilePath; A%\tiZe  
} cubUq5  
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public void setSFilePath(String value) >ulY7~wUv  
{ \b*X:3g*  
sFilePath = value; ]8;n{ }X  
} #;#3%?  
`8\Ja$ =  
/VHi>  
public String getSFileName() T5O _LCIws  
{ NcM>{{8  
return sFileName; bY~@}gC**@  
} [/RM=4Nh5  
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public void setSFileName(String value) nIfCF,
6,  
{ Wn|&cG9  
sFileName = value; xdy^^3"  
} y/c%+Ca/  
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public int getNSplitter() D,ly#Nn  
{ OVk~N)  
return nSplitter; uENdI2EY8y  
} M*pRv  
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R\s!*)  
public void setNSplitter(int nCount)
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{ [XlB<P=|>  
nSplitter = nCount; "'Z- UV  
} 0F;,O3Q  
} 1f(DU4h  
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G"y.Z2$  
/* PKq
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**Utility.java 8X&Ya =  
*/ "?.~/@  
package NetFox; <1~^C  
%"A_!<n@*`  
[{&jr]w`|  
public class Utility { q\9d6u=Gm  
I]}>|  
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public Utility() }PeZO!K  
{ ,,=apyr#&  
sP$Ks#/  
"t(wG{RxY  
} >adV(V<  
Ov9Q?8KzM  
//线程睡眠 .+K S`  
public static void sleep(int nSecond) B>TSdn={>  
{ RM*f|j  
try{ 0&fl#]oCE  
Thread.sleep(nSecond); /owO@~G  
} #^mqQRpgq  
catch(Exception e) ^~L}<]  
{ ?Hy+'sq[  
e.printStackTrace (); rlznwfr7+  
} Bo\D.a(T  
} 2>hz_o{5',  

2RppP?M!  
//日志 V{Q kN7-  
public static void log(String sMsg) ]re'LC!d  
{ %c6E-4b  
System.err.println(sMsg); "<l<& qp  
} G5'_a$  
b7h+?!H]R  
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public static void log(int sMsg) qSiWnN8D t  
{ \3PE+$  
System.err.println(sMsg); cBEHH4U  
} t;#Gmo  
} zX5G;,_  
fnH3CE  
#o[\Dwu  
/* Dl;d33  
**TestMethod.java KAb(NZK  
*/ ^b53}f8H  
package NetFox; OV5e#AOy)  
[!?wyv3  
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public class TestMethod { QB 77:E  
bsO@2NP'  
8sw,k   
public TestMethod() HcJE0-"  
{ ///xx/weblogic60b2_win.exe l C\E  
try{ i7eI=f-
Q  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); e.X@] PQJQ  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); n,KA&)/s  
SiteFileFetch fileFetch = new SiteFileFetch(bean); aR:<<IF\  
fileFetch.start(); LV.&>@*  
} [b`6v`x  
catch(Exception e){e.printStackTrace ();} ')nnWlK  
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}  Tb#
  
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2a[9h#  
public static void main(String[] args) En5!"w|j  
{ KU2$5[~j  
new TestMethod(); fI11dE9&?[  
} $!`L"szqD*  
} 5G?.T?  
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