http断点续传简单实现（java)

/* RVatGa0  
**SiteFileFetch.java z3+@[I$  
*/ .d1ff];  
package NetFox; 9;e!r DW,#  
import java.io.*; k
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import java.net.*; f$xXR$mjf  
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public class SiteFileFetch extends Thread { yDafNH  
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SiteInfoBean siteInfoBean = null; //文件信息Bean z$%twBg}#  
long[] nStartPos; //开始位置 eIkKsgr>  
long[] nEndPos; //结束位置 Food<(!.>  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Y~I<Locv  
long nFileLength; //文件长度 Jbu2y'zE  
boolean bFirst = true; //是否第一次取文件 oFWb.t9<  
boolean bStop = false; //停止标志 1#A$&'&\J;  
File tmpFile; //文件下载的临时信息 53])@Mmus  
DataOutputStream output; //输出到文件的输出流 3PNdc}h&#  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） faQmkO  
public SiteFileFetch(SiteInfoBean bean) throws IOException !RI _Uph  
{ rm[C{Pn  
siteInfoBean = bean; j<p.#jkT  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); I%3[aBz4  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); M|*YeVs9#  
if(tmpFile.exists ()) pZnp!!G  
{ D<SC
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bFirst = false; a `R%\@1  
read_nPos(); JX
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} w>%@Ug["  
else &?@C^0&QV  
{ jW'YQrj{<Y  
nStartPos = new long[bean.getNSplitter()]; SGAzeymw  
nEndPos = new long[bean.getNSplitter()]; vgwpuRL5b  
} n3a.)tcC  
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} :o'x?]  
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public void run() |./mPV r  
{ G4)~p!TSQ  
//获得文件长度 vY4sU@+V  
//分割文件 %_OjmXOfe  
//实例FileSplitterFetch Fv$tl)p*  
//启动FileSplitterFetch线程 4ijtx)SA  
//等待子线程返回 N''QQBUD  
try{ Hb)FeGsd).  
if(bFirst) ax&?Z5%a  
{ /{^k8 Q  
nFileLength = getFileSize(); }Pcm'o_wT  
if(nFileLength == -1) 2d&F<J<sU  
{ ;k<dp7^  
System.err.println("File Length is not known!"); 80=0S^gEZ  
} :7v'[b  
else if(nFileLength == -2) b:dN )m  
{ 2*:q$c  
System.err.println("File is not access!"); aGD< #]  
} C96/   
else R_!.vGhkN  
{ jeC=s~  
for(int i=0;i<nStartPos.length;i++) QQ(}71U  
{ L+am-k:T~  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 3Ua?^2l  
} NAR6q{c  
for(int i=0;i<nEndPos.length-1;i++) :viW  
{ (>al-vZ6A  
nEndPos = nStartPos[i+1]; lzEynMO+  
} qe0D[L  
nEndPos[nEndPos.length-1] = nFileLength; .GrOdDK$ns  
} `/8@Fj  
} u^Q`xd1  
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n7Ao.b%uk-  
//启动子线程 SMN.AJ J  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 9d5$cV  
for(int i=0;i<nStartPos.length;i++) Tc WCr  
{ QNNURf\[(  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), -#v~;Ci  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), da$FY7  
nStartPos,nEndPos,i); zxyl+tU &  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); :`bC3Mr  
fileSplitterFetch.start(); +jLy>=u  
} ^b8~X [1J_  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), $Z]&3VxxY  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); "=h1gql'  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", xcB\Y:   
nEndPos = " + nFileLength); vSgT36ZF  
// fileSplitterFetch[nPos.length-1].start(); P?0X az  
t<H"J__&  
At Wv9  
//等待子线程结束 t-\+t<;
 
//int count = 0; *6Wiq5M>.  
//是否结束while循环 (V{/8%mWc  
boolean breakWhile = false; 8Y($ F2  
eADCT  
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while(!bStop) LPvp (1  
{ EZUaYp~M  
write_nPos(); fQ<sq0'e\  
Utility.sleep(500); RZa/la*  
breakWhile = true; [|(|"dh@^H  
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for(int i=0;i<nStartPos.length;i++) ,B
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{ (5yM%H8:  
if(!fileSplitterFetch.bDownOver) :/5m D  
{ pjeNBSu6  
breakWhile = false; sZ `Tv[  
break; AxEyXT(h5  
} =?i?-6M  
} &W<7!U:2m  
if(breakWhile) #ArrQeO 5_  
break; 6h:QSVfx  
d ^bSV4  
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//count++; OH`a3E{e  
//if(count>4) \6b~$\~B  
// siteStop(); u$nzpw0=H  
} k&Pt\- 9on  
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System.err.println("文件下载结束！"); h@,ja  
} ]J7qs
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catch(Exception e){e.printStackTrace ();} =KE7NXu]-  
} SuE~Wb5&  
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//获得文件长度 &[E\2 E  
public long getFileSize() u64#,mC[*  
{ bC{4a_B  
int nFileLength = -1; *$Q>Om]  
try{ iq&3S0  
URL url = new URL(siteInfoBean.getSSiteURL()); ipSMmpB  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); +H-=`+,  
httpConnection.setRequestProperty("User-Agent","NetFox"); (NJ{>@&  
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int responseCode=httpConnection.getResponseCode(); BA;r%?MRL  
if(responseCode>=400) (.J/Ql0Y  
{ MO`Y&<g~A  
processErrorCode(responseCode); T.bFB+'E|  
return -2; //-2 represent access is error J Enjc/  
} qGinlE&\  
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String sHeader; d4Uw+3ikW  
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for(int i=1;;i++) @6 he
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{ }\a#e^-xQ+  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); g"-j/ c  
//Utility.log(in.readLine()); K
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sHeader=httpConnection.getHeaderFieldKey(i); Cfi{%,em  
if(sHeader!=null) Jh"[ug  
{ !3b& S4  
if(sHeader.equals("Content-Length")) :.:^\Q0  
{ oW^b,{~V  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); -#\T  
break; &;PxDlY5  
} 8Km&3nCv$Q  
} Gek?+|m  
else PGTEIptX7  
break; LjZlKB5C  
} C5~#lNC  
} t{k:H4  
catch(IOException e){e.printStackTrace ();} !I7$e&Uz@  
catch(Exception e){e.printStackTrace ();} ff--y8h  
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Utility.log(nFileLength); F^dJ{<yX  
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return nFileLength; =*UK!y?n  
} ;d
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//保存下载信息（文件指针位置） %i9S"  
private void write_nPos() ;,{_=n>  
{ E$"NOR  
try{ @@Ib^sB%  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ?9 huuJs7  
output.writeInt(nStartPos.length); (4H\ho8+mp  
for(int i=0;i<nStartPos.length;i++) SioeIXU  
{ h.<f%&)F  
// output.writeLong(nPos); [S6u:;7  
output.writeLong(fileSplitterFetch.nStartPos); fUw:jExz  
output.writeLong(fileSplitterFetch.nEndPos); "Q:Gd6?h;  
} x^s,<G  
output.close(); NaR} 0  
} t{})
6  
catch(IOException e){e.printStackTrace ();} ,,H5zmgA  
catch(Exception e){e.printStackTrace ();} VDxm|7  
} k1
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9<mMU:  
//读取保存的下载信息（文件指针位置） Wn<?_}sa|z  
private void read_nPos() l*ltS(?  
{ ,TBOEu."4  
try{ _c>iux;  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); B
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int nCount = input.readInt(); b(K"CL\p  
nStartPos = new long[nCount]; /k.0gYD  
nEndPos = new long[nCount]; E'6>3n  
for(int i=0;i<nStartPos.length;i++) "L>'X22ed  
{ #*(}%!rD*  
nStartPos = input.readLong(); ;4O[/;i  
nEndPos = input.readLong(); OVL
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} HLyAzB~r  
input.close(); [6VB&   
} Z`TfS+O6  
catch(IOException e){e.printStackTrace ();} 1/$PxQ  
catch(Exception e){e.printStackTrace ();} -2hirA<^  
} * + T(i  
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private void processErrorCode(int nErrorCode) y##h(y  
{ ,{*g Q%7  
System.err.println("Error Code : " + nErrorCode); 2ZK]}&yC  
} UyGo0POW  
]J Yz(m[   
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//停止文件下载 q1ysT.{p,  
public void siteStop() )zL@h  
{ dGZie.Zx  
bStop = true; J2O,wb)U  
for(int i=0;i<nStartPos.length;i++) KjGu !B
 
fileSplitterFetch.splitterStop(); a>j}@8[J  
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} u^MKqI  
} ~&Z>fgOTJ  
//负责部分文件的抓取 J3yK^@&&  
**FileSplitterFetch.java e#[Klh$]EW  
*/ s^u Y  
package NetFox; (.-4Jn  
-
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import java.io.*; h
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import java.net.*; l>6tEOXt  
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public class FileSplitterFetch extends Thread { M+ [ho]  
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String sURL; //File URL %`]+sg[i  
long nStartPos; //File Snippet Start Position UytMnJ88  
long nEndPos; //File Snippet End Position 56AC%_ g>  
int nThreadID; //Thread's ID t}+/GSwT  
boolean bDownOver = false; //Downing is over NK|UeL7ght  
boolean bStop = false; //Stop identical B&cIx~+  
FileAccessI fileAccessI = null; //File Access interface >)M{^  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Xs2}n^#i  
{ x^1udK^re  
this.sURL = sURL; U[wx){[|  
this.nStartPos = nStart; +M"j#H  
this.nEndPos = nEnd; &%OY"Y~bI!  
nThreadID = id; .UPh  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 G9:XEEN  
} bRvGetX  
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public void run() a=2.Y?  
{ Y4k2=w:D  
while(nStartPos < nEndPos && !bStop) wm~7`&  
{ "3RFyi  
3
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try{ xF8r+{_J)  
URL url = new URL(sURL); qFmw9\Fn  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); "\wMs  
httpConnection.setRequestProperty("User-Agent","NetFox"); ]oP1c-GEk  
String sProperty = "bytes="+nStartPos+"-"; K1@Pt}  
httpConnection.setRequestProperty("RANGE",sProperty); Z"8lW+r*  
Utility.log(sProperty); $INB_/RE  
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InputStream input = httpConnection.getInputStream(); 7P1Pk?pxy  
//logResponseHead(httpConnection); '|[!I!WB`  
/h>g-zb  
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byte[] b = new byte[1024]; i.mv`u Dm  
int nRead; `*s:[k5k  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 3RaduN]  
{ @:>]jp}uq  
nStartPos += fileAccessI.write(b,0,nRead); JI>Y?1i0O  
//if(nThreadID == 1) SA TX_  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); `;85Mo:qJ  
} =v:?rY}  
H$%MIBz>$  
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Utility.log("Thread " + nThreadID + " is over!"); |Y uf/G%/  
bDownOver = true; $yx\2  
//nPos = fileAccessI.write (b,0,nRead); kyHli~Nr"  
} av'm$I|O  
catch(Exception e){e.printStackTrace ();} _w
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} sT?{  
} e"hfeNphz  
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//打印回应的头信息 ?oYO !  
public void logResponseHead(HttpURLConnection con) xSud
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{ LhL |ETrJ  
for(int i=1;;i++) e\6H.9=  
{ ^*AI19w!Ys  
String header=con.getHeaderFieldKey(i); U<'N=#A J  
if(header!=null) {T8;-H0H  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); SW9 C 8Q  
Utility.log(header+" : "+con.getHeaderField(header));  {b!{~q  
else YdhV a!Y  
break; "W(D0oy  
} g}W`LIasv  
} E+\?ptw  

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it}h8:^<  
public void splitterStop() o898pg  
{ <D|&)/#  
bStop = true; mz0{eO  
} f\ P0%  
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} >`
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/* $9YQ aN%  
**FileAccess.java aBC5?V*e%  
*//文件访问(定位，写) 4v_Ac;2m&  
package NetFox; wa[L[mw  
import java.io.*; s~7a-J  
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public class FileAccessI implements Serializable{ { {\oC$  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 KPToyCyR1  
RandomAccessFile oSavedFile; A}lxJ5h0  
long nPos; 'pt(  
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public FileAccessI() throws IOException /bykIUTKI  
{ 5qM$ahN3wH  
this("",0); lc <V_8  
} :of([e|u6  
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public FileAccessI(String sName,long nPos) throws IOException DZqG7p$u4i  
{ Sn[xI9}O  
oSavedFile = new RandomAccessFile(sName,"rw"); 5M=U*BI  
this.nPos = nPos; DQ8/]Z{H  
oSavedFile.seek(nPos); 0h1u W26^  
} x+Yo#u22  
yhKH} kR  
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public synchronized int write(byte[] b,int nStart,int nLen) ?;RY/[IX6  
{ uqcG3Pi  
int n = -1; U$5x#{AFp  
try{ J?V$V >d  
oSavedFile.write(b,nStart,nLen); byI" ?  
n = nLen; TyV~2pcN  
} L!:NL#M  
catch(IOException e) :|(YlNUv  
{ )Ra:s>  
e.printStackTrace (); eQi^d/yi  
} L]MWdD  
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return n; 0m3hL~0(a  
} Zv}F?4T~:  
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"" UyfC[  
} !Q"L)%)'A  
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}a
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/* 8Ay7I  
**SiteInfoBean.java 8(Az/@=n  
*/ ~g!!#ad  
package NetFox; p*PzfSLN  
,6]ID1o:y  
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public class SiteInfoBean { IN/$b^Um  
(EcP'F*;;y  
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private String sSiteURL; //Site's URL 79 4UY  
private String sFilePath; //Saved File's Path N&G'i.w/  
private String sFileName; //Saved File's Name 
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private int nSplitter; //Count of Splited Downloading File At@0G\^  
|"K%Tvxe  
Do(G;D`h+_  
public SiteInfoBean() '|gsmO  
{//nSplitter的缺省值为5 7l7VT
?<:  
//default value of nSplitter is 5 _1?uAQ3,  
this("","","",5); T"P}`mT  
} ~U w<e~  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) :uAL(3pQ  
{ (^W}uDPCB  
sSiteURL= sURL; cS Lj\'`b  
sFilePath = sPath; q5r7KYH{  
sFileName = sName; q+[ )i6!?  
this.nSplitter = nSpiltter; .=YV  
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+FNGRL  
} ;uAh)|;S#  
>e;jGk?-  
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public String getSSiteURL() h<LS`$PK;E  
{ Zsapu1HoL\  
return sSiteURL; lrc%GU):  
} k% \;$u=%  
:sw5@JdJ  
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public void setSSiteURL(String value) 8/p ]'BLf  
{ ->pU!f)\X  
sSiteURL = value; _f2rz+  
} jy0aKSn8  
mKtMI!FR  
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public String getSFilePath() h];H]15&  
{ 9Pg6,[*u  
return sFilePath; xppnBnu$7  
} +8ib928E  
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public void setSFilePath(String value) N'{Yhx u  
{ ~I N g9|  
sFilePath = value; :kcqf,7  
} &(<>} r  
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o.Ww.F  
public String getSFileName() QN;5+p
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{ Mm,\e6#*  
return sFileName; 3US`6Y"  
} YCP D+  
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public void setSFileName(String value) CV HKP[-  
{ %wl:>9]
 
sFileName = value; v9J1Hha#  
} w!*ZS~v/r  
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public int getNSplitter() Wk^{Tn/]  
{ B{0]v-w  
return nSplitter; FnVW%fh  
} B!<B7Q  
|{|B70v3Co  
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public void setNSplitter(int nCount) OE[7fDe'  
{ 5X3JQ"z  
nSplitter = nCount; tHaHBx1P  
} bkR~>F]FAu  
} 0-OKbw5%=b  
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/* 7Z+Fjy-B  
**Utility.java kqX%y  
*/ noaR3)  
package NetFox; ]~$@x=p2e  
1 39T*0C  
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public class Utility { U`N?<zm<oO  
Ax|'uvVAPT  
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public Utility() f3,LX]zKA  
{ dVq9'{[3  
Jo qhmn$j  
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} KiMlbF.~V  
*eD[[HbKX  
//线程睡眠 l %zbx"%x  
public static void sleep(int nSecond) s`Z.H5V>\  
{ V!*1F1  
try{ [< 9%IGH  
Thread.sleep(nSecond); fb0)("_
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} %qJg
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catch(Exception e) Qu/f>tJN;  
{ _&G_SNa  
e.printStackTrace (); +
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} 8T+o.w==  
} A'}!'1
  
V@RdvQy  
//日志 u1kCvi#N  
public static void log(String sMsg) H!FaI(YZl  
{ V*?QZ;hCP  
System.err.println(sMsg); Mx0~^l
 
} t?^!OJ:L  
[Ous|a[)o  
[[w-~hHH-  
public static void log(int sMsg) Ymnh%wS  
{ Qru&lAYc<  
System.err.println(sMsg); 3XUVUd~  
} Xsn M}  
} sJQ~:p0e  
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/* VNz?e&>  
**TestMethod.java ;9#W#/B  
*/ v}5YUM0H`  
package NetFox; m' j1  
g"!cO^GkT  
}/tf^@  
public class TestMethod { 2>.b~q@  
mo tW7|p.e  
ZL
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public TestMethod() "7fEL:|j  
{ ///xx/weblogic60b2_win.exe 
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try{ ,. ht ~AE  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); F;/^5T3wI  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); fGH
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SiteFileFetch fileFetch = new SiteFileFetch(bean); #u"@q< )  
fileFetch.start(); FP y}Wc*UA  
} 6]GHC
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catch(Exception e){e.printStackTrace ();} st.{AEv@  
(-;(wCEE  
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} "`S?q G  
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public static void main(String[] args) 04-@c  
{ jpXbFWgN  
new TestMethod(); 9!r0uU"  
} f;+.j/ +  
}
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