http断点续传简单实现（java)

/* f6`GU$H  
**SiteFileFetch.java :\His{%  
*/ %60 OS3  
package NetFox; 'OziP  
import java.io.*; d`B<\Y#{Us  
import java.net.*; 8iJB'#''*  
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public class SiteFileFetch extends Thread { qclc--fsE  
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SiteInfoBean siteInfoBean = null; //文件信息Bean &.*UVc2+Y  
long[] nStartPos; //开始位置 4.jRTL5-oj  
long[] nEndPos; //结束位置 /]xa}{^B  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 )XK\[tL  
long nFileLength; //文件长度 $P0q!  
boolean bFirst = true; //是否第一次取文件 '!Hs"{~{  
boolean bStop = false; //停止标志 6,3o_"J!  
File tmpFile; //文件下载的临时信息 gaY&2
  
DataOutputStream output; //输出到文件的输出流 >dt*^}*  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） gK[;"R)4o@  
public SiteFileFetch(SiteInfoBean bean) throws IOException tZ9i/=S  
{ $Xu3s~:S  
siteInfoBean = bean; Ytlzn%  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 3$k#bC  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); e;6KxvX~  
if(tmpFile.exists ()) SE]5cJ'>  
{ 4F~^RR"  
bFirst = false; 3Hom0g,V4  
read_nPos(); w#9KtW,tt  
} =L" 0]4K  
else PFh ^Z L  
{ /^BC Qaj  
nStartPos = new long[bean.getNSplitter()]; f`uRC-B/  
nEndPos = new long[bean.getNSplitter()]; 2(xC|  
} -y+>^45  
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} "S%t\  
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public void run() `S@TiD*  
{ )O~[4xV~  
//获得文件长度 .z`70ot?  
//分割文件 s3Vb2C*  
//实例FileSplitterFetch XWp8[Cxs  
//启动FileSplitterFetch线程 Iv6 q(c  
//等待子线程返回 {q?&h'#y  
try{ EMW6'  
if(bFirst) KeQcL4<  
{ YZBh}l6t  
nFileLength = getFileSize(); kW g.-$pp  
if(nFileLength == -1) 3`HK^((o  
{ @0?!bua_|  
System.err.println("File Length is not known!"); >0IZ%Wiz  
} C|$qVh>  
else if(nFileLength == -2) 6gg8h>b  
{ $E\|\g  
System.err.println("File is not access!"); d!
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} <=q} Nd\  
else ' [ 4;QYw  
{ G21o@38e  
for(int i=0;i<nStartPos.length;i++) yp.K-  
{ ^"/^)Lb!@M  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Cl}nPUoL  
} Nz,yd%ua  
for(int i=0;i<nEndPos.length-1;i++) 9B: 3Ha=  
{ DZ8
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nEndPos = nStartPos[i+1]; ` R6`"hx$  
} \2i7\U  
nEndPos[nEndPos.length-1] = nFileLength; #&&T1;z"#  
} _>;Wz7  
} !L
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IY`p7 )#i  
//启动子线程 =?fz-HB  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; $<^t][{  
for(int i=0;i<nStartPos.length;i++) Dm>"c;2  
{ IU
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fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), NI >%v  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 4>hHUz[_  
nStartPos,nEndPos,i); WlMcEje  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); S(Yd.Sp  
fileSplitterFetch.start(); E $@W~).!  
} u/zBz*zh  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), :S+K\  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); [. 5m}V  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", T #\  
nEndPos = " + nFileLength); "ZuuSi  
// fileSplitterFetch[nPos.length-1].start(); &XP(D5lf`B  
Bh>L"'.2  
d8j1L/e  
//等待子线程结束 P#,u9EIJ  
//int count = 0; QHEtG2  
//是否结束while循环 kmI0V
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boolean breakWhile = false; q+ $6D;9  
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while(!bStop) {4Of.  
{ Hcq.Lq;2:  
write_nPos(); 'rD6MY  
Utility.sleep(500); La26"C"X  
breakWhile = true; P3$eomX'  
<B"sp r&1  
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for(int i=0;i<nStartPos.length;i++) /0h *(nL  
{ <j'V}|3  
if(!fileSplitterFetch.bDownOver) p\6cpf  
{ aV3:{oL  
breakWhile = false; vJkc/7  
break; N%y i4  
} ]b/]^1-(b  
} )*,/L <  
if(breakWhile) @ D+ft
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break; 'Wonz<{'  
UkV?,P@l  
(C2 XFg_  
//count++; Nk`UQ~g$  
//if(count>4) Hd|l6/[xz  
// siteStop(); p5Q]/DhG  
} f^WTsh]  
--$o$EP`  
1^p/#jt  
System.err.println("文件下载结束！"); iTVe8eI  
} I$n=>s  
catch(Exception e){e.printStackTrace ();} d"$8-_K  
} "n-'?W!  
S;Bk/\2  
y}Ky<%A!P  
//获得文件长度 n\#YGL<n  
public long getFileSize() 29R-Up!SVN  
{ WL$^B@gXQ  
int nFileLength = -1; INZVe(z  
try{ yqK4 "F&  
URL url = new URL(siteInfoBean.getSSiteURL()); qfkHGW?1/j  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); |.IH4 K  
httpConnection.setRequestProperty("User-Agent","NetFox"); ,b+NhxdZ  
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int responseCode=httpConnection.getResponseCode(); mYBEjZB  
if(responseCode>=400) /'O8RUjN  
{ ^ k^y|\UtZ  
processErrorCode(responseCode); 97}]@xN=  
return -2; //-2 represent access is error BxY t*b%  
} h$>F}n j  
!,J# r  
73WSW/^F  
String sHeader; H#-3  
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.b:!qUE^  
for(int i=1;;i++) \>L,X_DL  
{ 5/48w-fnZ  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); q>q:ZV  
//Utility.log(in.readLine()); 0bNvmZ$  
sHeader=httpConnection.getHeaderFieldKey(i); bm588UQ  
if(sHeader!=null) +Qs]8*^?;  
{ >%JPgr/ 8  
if(sHeader.equals("Content-Length")) Otn,UoeeB  
{ ?I.9?cQXZ  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); x^f<G 6z  
break; FB=oGgwwq  
} R{hX--|j  
} bIKg>U'5d  
else od;-D~  
break; JuRoeq.  
} 'Pz%c}hJ  
} ]AP1+ &9fN  
catch(IOException e){e.printStackTrace ();} GnV0~?  
catch(Exception e){e.printStackTrace ();} <?jdNM  
93-Y(Xx)bY  
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Utility.log(nFileLength); >&L|oq7$  
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return nFileLength; <QtZ6-;_f  
} |J`EM7qMK  
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:-&|QVH  
//保存下载信息（文件指针位置） ?-??>& z  
private void write_nPos() .@dC]$2=  
{ U%{GLO   
try{ wI#8|,]"z  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 7AG|'s['=  
output.writeInt(nStartPos.length); WlL(NrVA@@  
for(int i=0;i<nStartPos.length;i++) l,wlxh$}(  
{ tz1@s nes  
// output.writeLong(nPos); T.q2tC[bR  
output.writeLong(fileSplitterFetch.nStartPos); Re%[t9F&  
output.writeLong(fileSplitterFetch.nEndPos); e~h>b.~  
} )W@ug,y  
output.close(); 6|97;@94  
} pMF vL  
catch(IOException e){e.printStackTrace ();} S"Al[{  
catch(Exception e){e.printStackTrace ();} vwR_2u  
} 5
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//读取保存的下载信息（文件指针位置） ?7{U=1gb$  
private void read_nPos() 5Z=4%P*I  
{ *%-<Ldv  
try{ .soCU8i3  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); }A9#3Y|F  
int nCount = input.readInt(); A`c22Ls]  
nStartPos = new long[nCount]; ,"qCz[aDN1  
nEndPos = new long[nCount]; "EW8ll7r  
for(int i=0;i<nStartPos.length;i++) M,G
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{ :XKYfc_y  
nStartPos = input.readLong(); ~G@NWF?7  
nEndPos = input.readLong(); $+gQnI3w  
} Ht`fC|E  
input.close(); /iW+<@Mas  
} ]kh]l8t^
 
catch(IOException e){e.printStackTrace ();} Rq4;{a/j  
catch(Exception e){e.printStackTrace ();} >Wg=
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} Y#U.9>h  
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private void processErrorCode(int nErrorCode) <y 4(!z"  
{ `RTxc  
System.err.println("Error Code : " + nErrorCode); @uSO~.7  
} Jcw^
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6#w>6g4V~R  
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//停止文件下载 QE<Z@/V*a  
public void siteStop() OqGp|`  
{ (qcFGM22U  
bStop = true; $C16}^  
for(int i=0;i<nStartPos.length;i++) OT#@\/>  
fileSplitterFetch.splitterStop(); +)jUA]hJ/  
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} l;F"m+B!$  
} ZvY"yl?e  
//负责部分文件的抓取 ,%i Scr,z  
**FileSplitterFetch.java T2{e1 =Z7  
*/ V:0IB
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package NetFox; }_Bo:*9B-o  
lH fZw})d  
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import java.io.*; ]aN9mT N  
import java.net.*; ,@"yr>Q9#6  
*i#2>=)  
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public class FileSplitterFetch extends Thread { VPN 9 Ql=  
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String sURL; //File URL A#>wbHjWF  
long nStartPos; //File Snippet Start Position 5-dt0I@<  
long nEndPos; //File Snippet End Position g&RpE41x  
int nThreadID; //Thread's ID "2e3 <:$  
boolean bDownOver = false; //Downing is over l;$F[/3a  
boolean bStop = false; //Stop identical "$BkO[IS  
FileAccessI fileAccessI = null; //File Access interface }gSoBu  
*oO%+6nL  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException r#-  
{ \F _1C=  
this.sURL = sURL; bLT3:q#s  
this.nStartPos = nStart; N2h5@*1Y  
this.nEndPos = nEnd; "|\hTRQ  
nThreadID = id; j/V_h'}  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 a)O"PA}2  
} as07~Xvp-  
-]%EX:bm  
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public void run() ,>|tQ'  
{ 2%/F`_XbP  
while(nStartPos < nEndPos && !bStop) O:]']' /  
{ 1N/4W6  
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try{
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URL url = new URL(sURL);
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 0+&WIs  
httpConnection.setRequestProperty("User-Agent","NetFox"); &Vj@){  
String sProperty = "bytes="+nStartPos+"-"; _ep&`K  
httpConnection.setRequestProperty("RANGE",sProperty); [[T7s(3  
Utility.log(sProperty); ,~L*N*ML  
=i~ = |K!  
ZllmaI  
InputStream input = httpConnection.getInputStream(); /cS8@)e4  
//logResponseHead(httpConnection); 'm0WPS/6E  
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byte[] b = new byte[1024]; /.:1
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int nRead; -6MPls+  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) _ $PeFE2  
{ lh-.I]>&`  
nStartPos += fileAccessI.write(b,0,nRead); l4gH]!/@  
//if(nThreadID == 1) q\tr&@4iC  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); /OKp(u;)z  
} VnuG^)S  
eKP>}`  
za>%hZf\  
Utility.log("Thread " + nThreadID + " is over!"); hu-]SGb6  
bDownOver = true; \ZnA%hC  
//nPos = fileAccessI.write (b,0,nRead); 1P]J3o  
}
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catch(Exception e){e.printStackTrace ();} /{R ^J#  
} DzC`yWstP  
} dX\OP>  
=K@LEZZ'/<  
f}dlQkZ(  
//打印回应的头信息 l_yy;e  
public void logResponseHead(HttpURLConnection con) F,YPIl  
{ &4E|c[HN
  
for(int i=1;;i++) ['QhC({  
{ $y;w
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String header=con.getHeaderFieldKey(i); II^Rp],>  
if(header!=null) ~U+<
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//responseHeaders.put(header,httpConnection.getHeaderField(header)); eg~ Dm>Es  
Utility.log(header+" : "+con.getHeaderField(header)); y0O(n/  
else UAjN  
break; Wv>`x?W  
} hGFi|9/-u  
} <\*)YKjn/@  
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public void splitterStop() $7X;FmlG&  
{ *Y1s4FXu2  
bStop = true; do`'K3a"  
} }51QUFhL0  
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} D~inR3(}  
~N/%R>(v  
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/* %X\J%Fj  
**FileAccess.java QM!UMqdj  
*//文件访问(定位，写) yS)k"XNb  
package NetFox; !/`AM<`o  
import java.io.*; r E1ouz!D  
l="(Hp%b  
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public class FileAccessI implements Serializable{ *K>2B99TXu  
5I*1CIO  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 .aL%}`8l?  
RandomAccessFile oSavedFile; 2w8YtM3+"z  
long nPos; j %MY6"  
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public FileAccessI() throws IOException {\?f|mmq  
{ gy1kb,MO  
this("",0); )YCH>Za  
} r<]^.]3zj  
Y&VypZ"G>  
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public FileAccessI(String sName,long nPos) throws IOException daY0;,>  
{ 4o''C |ND  
oSavedFile = new RandomAccessFile(sName,"rw"); qZQm*q(jM  
this.nPos = nPos; B'Nvl#  
oSavedFile.seek(nPos); FpttH?^  
} 6 y"r'  
h*4wi.-  
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public synchronized int write(byte[] b,int nStart,int nLen) ;8F6a:\v  
{ <)cmI .J3  
int n = -1; ,:.8s>+i  
try{ <-d-. 8  
oSavedFile.write(b,nStart,nLen); NgGpLdaC2v  
n = nLen; r
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} `,  |l  
catch(IOException e) 82
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{ |/-# N  
e.printStackTrace (); AED 9vDE  
} D9(4%^HxV1  
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return n; z:n JN%Qb  
} R]kH$0`  
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} T~>&m~} +  
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/* Mc  
**SiteInfoBean.java JjAO9j%  
*/ }WQ:Rmi  
package NetFox; $~EY:  
.GnoK?  
3,+UsB%  
public class SiteInfoBean { RXPl~]k#i  
;?o"{mbb  
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private String sSiteURL; //Site's URL a`||ePb|W~  
private String sFilePath; //Saved File's Path (ds*$]  
private String sFileName; //Saved File's Name fQU_
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private int nSplitter; //Count of Splited Downloading File a0FU[*q  
?!34qh  
E;a9RV|  
public SiteInfoBean() WsM/-P1Y  
{//nSplitter的缺省值为5 bF@iO316H  
//default value of nSplitter is 5 t5p#g<$  
this("","","",5); "MT{t><  
} m<9W#
 
,g)9ZP.F  
w68VOymD/  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) I>3G"[t
 
{ RML'C:1  
sSiteURL= sURL; Zfr?(y+3  
sFilePath = sPath; * 8D(Lp1  
sFileName = sName; I8hmn@ce  
this.nSplitter = nSpiltter; *u<@_Oa  
"jl`FAu)q  
3TD!3p8
  
} l5k]voG  
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2wh{[Q2f  
public String getSSiteURL() 5al44[  
{ Ks7k
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return sSiteURL; hWu#}iN  
} -E!V;Tgc%U  
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public void setSSiteURL(String value) |B*`%7{+  
{ CV,[x[L#{  
sSiteURL = value; qoD M!~  
} @l2AL9z$m>  
"2/VDB4!FG  
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public String getSFilePath() -Kf'02  
{ +%RXV~  
return sFilePath; `!T
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} kA:cz$)  
!NOvKC!  
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public void setSFilePath(String value) ">RDa<H]  
{ <$;fOp  
sFilePath = value; Z.0^:rVp~  
} >G+?X+9  
*SZ*S%oS3  
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public String getSFileName() ZGOI8M]@  
{ 7" cgj#  
return sFileName; RT2a:3f  
} dQFx]p3L  
$}7WJz:  
KH&xu,I  
public void setSFileName(String value) \oGZM0j  
{ D9&FCCiUE  
sFileName = value; aI8K*D )@  
} `Uw^,r  
P3YG:*  
bsmnh_YRj  
public int getNSplitter() 5k}UXRB?  
{ o' DXd[y  
return nSplitter; W,
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} ',* 6vbII  
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public void setNSplitter(int nCount) s.I=H^T  
{ f;%4
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nSplitter = nCount; m[u 6<C  
} S,v9\wN.  
} ^Q_0Zq^H  
*%cI,}%   
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/* I|$_[Sw  
**Utility.java [H)p#x  
*/ n
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package NetFox; A! 1>  
Hp":r%)  
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public class Utility { |^@TA
=_  
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public Utility() $y>J=  
{ r jL%M';  
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} p<6pmW3  
z{^XU"yB  
//线程睡眠 1}!f.cWV(  
public static void sleep(int nSecond) =RUKN38  
{
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try{ hD l+  
Thread.sleep(nSecond); *Qg/W?"m  
} Ph.$]yQCc]  
catch(Exception e) /^0Hi4+\  
{ J]|-.Wv1  
e.printStackTrace (); 5R,/X  
} U1rh[A>  
} Y6fU;  
JX/rAnc@  
//日志 9!FV.yp%F  
public static void log(String sMsg) zYj8\iER  
{ Q_1EAxt  
System.err.println(sMsg); Vo(d)"m?  
} +]|J  
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nS'0i&<{1  
public static void log(int sMsg) w];t]q|  
{ iygdX2  
System.err.println(sMsg); 8'#%7+ "=!  
} ,)Z^b$H]  
} Mi'eViH  
.'7o,)pJ<  
dmrM %a}W-  
/* #ZGWU_l}  
**TestMethod.java TiF$',WMv  
*/ }kXF*cVg  
package NetFox; wEzLfZ Oz/  
JVTG3:zD  
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mh  
public class TestMethod { oChcEx%  
WE`Y!  
|2c'0Ibu  
public TestMethod() Q9#$4  
{ ///xx/weblogic60b2_win.exe O*yc8fUI  
try{ ]Wv\$JXI  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); **0Y*Ax@  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); l=EIbh  
SiteFileFetch fileFetch = new SiteFileFetch(bean); } "y{d@  
fileFetch.start(); 6z=:x+m  
} I%*o7"  
catch(Exception e){e.printStackTrace ();} iAWPE`u4  
&g@?{5FP  
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}  D
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:fpYraBM  
/k}vm3  
public static void main(String[] args) %t%+;(M9  
{ b9w9M&?fT  
new TestMethod(); D 7H$!(F>  
} Ty#L%k}-t  
} g4j?E{M?  
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