http断点续传简单实现（java)

/* sYY=MD  
**SiteFileFetch.java 0!,)7  
*/ N0
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package NetFox; z/t:gc.  
import java.io.*; /WIHG0D  
import java.net.*; -Fs^^={Q  
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public class SiteFileFetch extends Thread { 2F#R;B#2  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ?#X`Eu  
long[] nStartPos; //开始位置 @OPyT  
long[] nEndPos; //结束位置 )SYZ*=ezl.  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ;j/-
ndd&&  
long nFileLength; //文件长度 6'N!)b^-  
boolean bFirst = true; //是否第一次取文件 )04lf*ti  
boolean bStop = false; //停止标志 ';?b99  
File tmpFile; //文件下载的临时信息 /A) v$Bv=  
DataOutputStream output; //输出到文件的输出流 a4M`Bk;mb  
]]Da/^K=Z  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） +kTa>U<?  
public SiteFileFetch(SiteInfoBean bean) throws IOException _;+N=/l0  
{ $0K%H  
siteInfoBean = bean; 0IEFCDeCO  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ^R4eW|H  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); k6 f;A  
if(tmpFile.exists ()) |79!exVMBp  
{  ]=g|e  
bFirst = false; x9NLJI21/  
read_nPos(); (FAd'$lhX}  
} 6\9 9WQ  
else d/OIc){tD  
{ <WGl4#(k  
nStartPos = new long[bean.getNSplitter()]; cnOk  
nEndPos = new long[bean.getNSplitter()]; wp,z~raaS  
} :B'}#;8_  
:{tvAdMl7  
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} :22IY>p  
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public void run() oa?
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{ $V)LGu2(m  
//获得文件长度 ]4>[y?k34  
//分割文件 b
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//实例FileSplitterFetch ^9UF Pij"  
//启动FileSplitterFetch线程 HYPFe|t/  
//等待子线程返回 +B@NSEy/+  
try{
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if(bFirst) VBssn]w  
{ 3EcmNwr
 
nFileLength = getFileSize(); <z|?C  
if(nFileLength == -1) u-h3xj  
{ 0PnW|N0  
System.err.println("File Length is not known!"); TUEEwDK-  
} '.@R_sj
  
else if(nFileLength == -2) j]<T\O>t>  
{ 0\jOg  
System.err.println("File is not access!"); 3Fn26Rij  
} 7 v<$l  
else #?i#q%q  
{ y=\jQ6Fc  
for(int i=0;i<nStartPos.length;i++) Tc)T0dRP  
{ %f&(U/  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); mor
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} |pp@  
for(int i=0;i<nEndPos.length-1;i++) ?8(`tS(_?  
{ S~F:%@,*  
nEndPos = nStartPos[i+1]; T}[W')[s  
} As (C8C<  
nEndPos[nEndPos.length-1] = nFileLength; h& (@gU`A  
} 2`vCQV  
} Q[p0bD
:  
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)B*?se]LJ  
//启动子线程 ?4Z0)%6  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; jl2nRo  
for(int i=0;i<nStartPos.length;i++) )
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{ S_:(I^  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), @6$r|:]G-  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ooIMN =  
nStartPos,nEndPos,i); >UJ&noUD#:  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ),\>'{~5&  
fileSplitterFetch.start(); `z)!!y  
} }]zmp/;a  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), GGF;T&DWad  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); {zUc*9  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", "\BP+AF  
nEndPos = " + nFileLength); Whd4-pR8  
// fileSplitterFetch[nPos.length-1].start(); }C7tlA8,7  
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#s
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//等待子线程结束 G-3.-  
//int count = 0; #K!Df%,<  
//是否结束while循环 pLzsL>6h  
boolean breakWhile = false; *!9/`zW  
:/vB,JC  
U&3*c+B4  
while(!bStop) hDlk! #*  
{ RC (v#G  
write_nPos(); Ti3BlWQH  
Utility.sleep(500); {u.V8%8  
breakWhile = true; bOck^1Hky  
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for(int i=0;i<nStartPos.length;i++) &OhKx  
{ o@LjSQ5!  
if(!fileSplitterFetch.bDownOver) &"tce6&
 
{ \ @N>38M  
breakWhile = false; ?3}UO:B  
break; EJWMr`zdn  
} 38q@4U=aiw  
} ,uKvE`H  
if(breakWhile) &{]%=stI  
break; @su{Uno8/  
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F|  
fSqbGoIQ  
//count++; dBlOU.B  
//if(count>4) U*&ZQw  
// siteStop(); {yb\p9q{Yo  
} YRp\#pVnZ  
J82{PfQ"  
~2H7_+.#  
System.err.println("文件下载结束！"); Jl]]nOBQ/  
} kmc9P&  
catch(Exception e){e.printStackTrace ();} u=E?N:I~F  
} '-i tn  
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p fBO5Ys  
//获得文件长度 _kY5
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public long getFileSize() zi?'3T%Ie  
{ 3yKI2en"  
int nFileLength = -1; AVyZ#`,  
try{ MW`a>'0t?  
URL url = new URL(siteInfoBean.getSSiteURL()); /a$+EQ$  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); D`t
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httpConnection.setRequestProperty("User-Agent","NetFox"); rmMO-!s  
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int responseCode=httpConnection.getResponseCode(); jujx3rnK?  
if(responseCode>=400) D} .t  
{ /XSPVc<  
processErrorCode(responseCode); tJwF h6  
return -2; //-2 represent access is error l#~FeD  
} r0X2cc  
/M3D[aR<d  
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EHc)  
String sHeader; }a9C/t3  
p_z"Uwp  
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for(int i=1;;i++) &16bZw  
{ ,{Ab=xV  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); X#3<hN*v  
//Utility.log(in.readLine()); )2FO+_K?T  
sHeader=httpConnection.getHeaderFieldKey(i); fjWh}w8  
if(sHeader!=null) gNqV>p  
{ 2YN`:"  
if(sHeader.equals("Content-Length")) '.K,EM!-~h  
{ Wl#^Eu\g1W  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); {;4PP463  
break; Qi[D&47XO  
} t<|s&  
} .u*].As=  
else t~M<j|]k  
break; y[|g!9Rp  
} =+"'=o  
} ;yZ N "r  
catch(IOException e){e.printStackTrace ();} +E [bLz^  
catch(Exception e){e.printStackTrace ();} *(`.h\+  
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Utility.log(nFileLength); &!a2%%1#N  
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return nFileLength; 5HbTgNI  
} - X_w&  
6J 5)4^bk  
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//保存下载信息（文件指针位置） 'YR5i^:t  
private void write_nPos() w+37'vQ  
{ yo.SPd="Vx  
try{ "<2bjy  
output = new DataOutputStream(new FileOutputStream(tmpFile)); {T.Vu]L80  
output.writeInt(nStartPos.length); v 2GhR*  
for(int i=0;i<nStartPos.length;i++) O<h#|g1  
{ z`5I1#PVA  
// output.writeLong(nPos); Ozv.;}SE  
output.writeLong(fileSplitterFetch.nStartPos); vs@:L)GW\  
output.writeLong(fileSplitterFetch.nEndPos); spx;QLo  
} 2SJh
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output.close(); %^l&fM*  
} u}1vn}F{  
catch(IOException e){e.printStackTrace ();} )/Xrhhx  
catch(Exception e){e.printStackTrace ();} / 3k\kkv!  
}
5lxq-E3  
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//读取保存的下载信息（文件指针位置） x!~OK::o8  
private void read_nPos() %~5Q^3$O  
{ GF!{SO4  
try{ GnOo+hB  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); W`'|&7~  
int nCount = input.readInt(); V 3]p3  
nStartPos = new long[nCount]; )M N yOj  
nEndPos = new long[nCount]; tKeO+6l  
for(int i=0;i<nStartPos.length;i++) XC1lo4|  
{ erP>P  
nStartPos = input.readLong(); 9,5II0N L  
nEndPos = input.readLong(); 62x< rph  
} &&]!+fTZ\(  
input.close(); vEe  
} ++!E9GU{  
catch(IOException e){e.printStackTrace ();} &{/>Sv!6#  
catch(Exception e){e.printStackTrace ();} i`aG  
} (YJAT  
#=H}6!18  
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private void processErrorCode(int nErrorCode) -b)zira  
{ G`#
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System.err.println("Error Code : " + nErrorCode); ,A!e
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} b<(UmRxx3  
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9;Pu9s[q2  
//停止文件下载 ) .-(-6=R  
public void siteStop() A Wh*<H  
{ :$cSQ(q9a  
bStop = true; a H|OA\<  
for(int i=0;i<nStartPos.length;i++) 
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fileSplitterFetch.splitterStop(); _{`'{u  
@ U8}sH^  
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} e=]oh$]  
} h NOYFH  
//负责部分文件的抓取 "4k=(R?  
**FileSplitterFetch.java 1xdESorX(  
*/ _IKP{WNB  
package NetFox; @j\?h$A/  
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({_:^$E\  
import java.io.*; ?J@?,rZQ^V  
import java.net.*; x$5nLS2.  
;*4tVp,  
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public class FileSplitterFetch extends Thread { FP'u)eU&3  
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String sURL; //File URL &iND&>?  
long nStartPos; //File Snippet Start Position Xq^y<[  
long nEndPos; //File Snippet End Position ^z%o];  
int nThreadID; //Thread's ID }M9DqZ;I  
boolean bDownOver = false; //Downing is over Nzi/3r7m  
boolean bStop = false; //Stop identical R3{*v =ov  
FileAccessI fileAccessI = null; //File Access interface %AEK[W+0  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException t1:
S!@  
{ 8/>wgY  
this.sURL = sURL; 3^A/`8R7K  
this.nStartPos = nStart; ,F?~'-K  
this.nEndPos = nEnd; 28Ssb|  
nThreadID = id; ;x3 ]4^  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 J<($L}T*$  
} nhQ44qRgQ  
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public void run()  ny  
{ 3dX=xuQ%/  
while(nStartPos < nEndPos && !bStop) @1/}-.(n  
{ jgo<#AJ/E  
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try{ !7kLFW  
URL url = new URL(sURL); H81.p  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); PX69  
httpConnection.setRequestProperty("User-Agent","NetFox"); /_:T\`5uO  
String sProperty = "bytes="+nStartPos+"-"; @O<@f8-  
httpConnection.setRequestProperty("RANGE",sProperty); #lyM+.
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Utility.log(sProperty); K[#v(<)  
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InputStream input = httpConnection.getInputStream(); |auX*hb9  
//logResponseHead(httpConnection); 1O]5/Eu  
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byte[] b = new byte[1024]; rAlh& ?X  
int nRead; i!.I
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while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Wlr&g xZ  
{ h=K36a)  
nStartPos += fileAccessI.write(b,0,nRead); e\^g|60f_  
//if(nThreadID == 1) w]W`R.  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); PzMlua  
} ~E<PtDab  
^EC)~HP@C  
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@  
Utility.log("Thread " + nThreadID + " is over!"); :tjgg]  
bDownOver = true; 409x!d~it  
//nPos = fileAccessI.write (b,0,nRead); <uBhi4  
} #Cg}!38  
catch(Exception e){e.printStackTrace ();} +#-kIaU  
} ^&`
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} Mz/]DJ8  
+gbX}jF0%  
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//打印回应的头信息 )]c]el@y  
public void logResponseHead(HttpURLConnection con) LXh@o1  
{ KJ0xp hf  
for(int i=1;;i++) (^DLCP#*  
{ WA]%,6  
String header=con.getHeaderFieldKey(i); :Wyn+  
if(header!=null) P0'e"\$  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); H})Dcg3  
Utility.log(header+" : "+con.getHeaderField(header)); i14[3bPLk!  
else VjA wn}eO  
break; 7]/dg*A )C  
} K9e~Wl<3  
} 2YE;m&  
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public void splitterStop() 2~G,Ia  
{ W"b&M%y|  
bStop = true; QMXD9H0{  
} O8K@&V
p  
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} Xmap9x  
Q vv\+Jp^  
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/* rxs~y{Xi  
**FileAccess.java Z&+NmOY4  
*//文件访问(定位，写) /v}P)&  
package NetFox; 5u2{n rc  
import java.io.*; XKz;o^1a^  
)z2|"Lp  
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public class FileAccessI implements Serializable{ 4zo4H~@gk  
rao</jN.9  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ?1GY%-  
RandomAccessFile oSavedFile; ^lHb&\X  
long nPos; 1fz*SIjG  
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public FileAccessI() throws IOException fOa6,  
{ kZV^F*7  
this("",0); |?OdV<5C  
} fH{9]TU_:  
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public FileAccessI(String sName,long nPos) throws IOException &Q\_;  
{ ! (2-(LgA  
oSavedFile = new RandomAccessFile(sName,"rw"); 9 9Ba{qj  
this.nPos = nPos; !MZ+-dpK  
oSavedFile.seek(nPos); RL?u n}Qa  
} u] F70C^~  
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public synchronized int write(byte[] b,int nStart,int nLen) L8K0^~Mk  
{ 4`'8fe/"  
int n = -1; [8,PO  
try{ O0@w(L-  
oSavedFile.write(b,nStart,nLen); 6eOrs-ty  
n = nLen; I\}|Y+C$d/  
} z=ML(1c=  
catch(IOException e) OJv}kwV  
{ |BwRlE2CFO  
e.printStackTrace (); El~-M`Gf  
} UH5w7M  
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return n; +O)]^"TG  
} 3^!Hl8P7  
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}  DZ^=*.  
X Y~;)<s_  
.qSBh hH\  
/* "Kyifw?  
**SiteInfoBean.java /nc~T3j  
*/ {*N^C@  
package NetFox; .4wTjbO6  
fJX\'Rc\  
 KR&s?  
public class SiteInfoBean { }0$mn)*k  
2< p{z  
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private String sSiteURL; //Site's URL fs&,
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private String sFilePath; //Saved File's Path ]\OWZ{T'j  
private String sFileName; //Saved File's Name W@l+ciZ_  
private int nSplitter; //Count of Splited Downloading File 3@&bxYXm  
o>2e!7  
c\M#5+1j  
public SiteInfoBean() 6^Ph '  
{//nSplitter的缺省值为5 {]=v]O|,  
//default value of nSplitter is 5 IQT cYl  
this("","","",5); 3=Z<wD s  
} {] O`gG  
,:^ N[b   
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) x
;Gz6|  
{ IeVLn^?+:  
sSiteURL= sURL; JL.5QzA  
sFilePath = sPath; NjbwGcH%\  
sFileName = sName; z+jh;!i  
this.nSplitter = nSpiltter; tG/1p

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8 4z6zFv?Q  
} 2 #KoN8%  
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public String getSSiteURL() {1~9vHAZ  
{ 9SY(EL  
return sSiteURL; JX{KYU  
} .8]Y-  
6
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Kh)FyV  
public void setSSiteURL(String value) BBvZeG $Y  
{ L!gDFZr  
sSiteURL = value; jPnO@H1  
} z!:'V]  
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:lK4 db  
public String getSFilePath() p'&*r2_ram  
{ ob'n{T+lZ  
return sFilePath; 
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} ;W0]66&  
+
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2/@D7>F&g  
public void setSFilePath(String value) >\ZR*CS  
{ k5@d! }#c  
sFilePath = value; 8a9RML}G<  
} =<{ RX8  
{rC~P  
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public String getSFileName() kg3ppt  
{ h~w4, T  
return sFileName; ~s#e,Kav"  
} X2gz6|WJ  
^Gq5ig1rxy  
8%[HYgd5)  
public void setSFileName(String value) B;!f<"a8  
{ +yWR#[`n  
sFileName = value; RZO5=L9E  
} 6Nt
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(;}tf~~r  
#.<V^  
public int getNSplitter() 6^;^rUlm  
{ '"'Btxz  
return nSplitter; H] k'?;  
} jJ~Y]dQi  
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0+EN@Y^dAV  
public void setNSplitter(int nCount) Uki9/QiX>  
{ 8Bpip  
nSplitter = nCount; .^[_V  
} .$Bwb/a  
}  ]>Si0%  
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/* 7yI`e*EOD  
**Utility.java dn,gZ"<  
*/ $D'^t(  
package NetFox; WA.AFt  
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public class Utility { >|3a 9S  
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public Utility() Km3&N  
{ DA"}A`HfI  
@T&t.|`  
:EZQ'3X  
} Y-p<qL|_  
\k@Z7+&7  
//线程睡眠 dB;3.<S=  
public static void sleep(int nSecond) "&lN\&:  
{ Z0ReWrl;`  
try{ ~ y;y(4<  
Thread.sleep(nSecond); j7 d:v7+_  
} J!h^egP  
catch(Exception e) '<@=vGsye  
{ dTGA5c  
e.printStackTrace (); 7zDiHac  
} = .oHnMX2M  
} *Oo &}oAj  
}nud  
//日志 NQ9Ojj{#  
public static void log(String sMsg) w#(RW7":F  
{ [f!O6moR6  
System.err.println(sMsg); c8A`<-\MfB  
} &|5GB3H=  
},c,30V'  
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public static void log(int sMsg) kWL.ewTiex  
{ 4;KWG}~[o  
System.err.println(sMsg); 0JY WrPR  
} [VSU"AJ
Y  
} EO)%UrWnC  
+.Bmkim  
&uM^0eM  
/* GXX+}=b7qO  
**TestMethod.java SwH2$:f  
*/ &ZJgQ-Pc(m  
package NetFox; ^#e~g/  
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'v&}(  
public class TestMethod { O~@fXMthh  
8
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>UHa  
public TestMethod() C!%:o/  
{ ///xx/weblogic60b2_win.exe ;sPzOS9  
try{ #[ -\lU|  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); @5<CXTdF9c  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); D59T?B|BdD  
SiteFileFetch fileFetch = new SiteFileFetch(bean); PRs@zkO  
fileFetch.start(); J]pa4C`  
} eThy+  
catch(Exception e){e.printStackTrace ();} I@ \#up}  
"5!BU&   
.g% Y@r)=5  
} vtxvS3   
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public static void main(String[] args) >V;,#5F_  
{ qv+R:YYOq  
new TestMethod(); Bjj<\8^M  
} UUtbD&\  
} <I=$ry6 8  
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