http断点续传简单实现（java)

/* I#OZ:g^  
**SiteFileFetch.java #N][-i  
*/ WOO3z5 La  
package NetFox; L(
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import java.io.*; "]eB2k_>  
import java.net.*; kXL0  
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public class SiteFileFetch extends Thread { ;` L%^WZ;-  

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SiteInfoBean siteInfoBean = null; //文件信息Bean |sGJum&=  
long[] nStartPos; //开始位置 ,a>Dv@$Y  
long[] nEndPos; //结束位置 pLu5x<  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ;pm/nu  
long nFileLength; //文件长度 ;MQl.?vj  
boolean bFirst = true; //是否第一次取文件 N:B<5l '  
boolean bStop = false; //停止标志 t^&hG7L_m,  
File tmpFile; //文件下载的临时信息 l;q]z  
DataOutputStream output; //输出到文件的输出流 
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） \`y:#N<c  
public SiteFileFetch(SiteInfoBean bean) throws IOException N8nt2r<h  
{ UlWmf{1%]?  
siteInfoBean = bean; >,,`7%Rv  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Ar)EbGId  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); |Ua);B~F  
if(tmpFile.exists ()) _)j\ b  
{ ?GX@&_
  
bFirst = false; :i{M1z I  
read_nPos(); |OLXb+7X  
} r`-8+"P  
else T'6`A<`3  
{ }k.yLcXM  
nStartPos = new long[bean.getNSplitter()]; 6"_pCkn;c<  
nEndPos = new long[bean.getNSplitter()]; 1L`V{\_0s  
} ,hf W2}  
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} w<~[ad}  
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public void run() 0=&S?J#!  
{ H`M|B<.  
//获得文件长度 bGwOhd<.  
//分割文件 BvvjaC  
//实例FileSplitterFetch {_!,T%>+1  
//启动FileSplitterFetch线程 p"P+8"`  
//等待子线程返回 ^U?Ac=  
try{ UIU Pi gd  
if(bFirst) m=n79]b:N  
{ ;%0kzIvP  
nFileLength = getFileSize(); bj`GGxzOb  
if(nFileLength == -1) KC"S06  
{ B.=n U  
System.err.println("File Length is not known!"); t<dFH}U`w  
} XZN@hXc9:v  
else if(nFileLength == -2) T 9`AL  
{ jW7ffb `O  
System.err.println("File is not access!"); ;o'>`=Y  
} K bQXH!J  
else xq.kH|bH  
{ aA$\iFYA  
for(int i=0;i<nStartPos.length;i++) P$z%:Q  
{ ;i.MDW^N  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); tQG'f*4  
} PCwc=  
for(int i=0;i<nEndPos.length-1;i++) N( 7(~D=)B  
{ 5$!idfDr|m  
nEndPos = nStartPos[i+1]; +UWv}|  
} ?#a&eW  
nEndPos[nEndPos.length-1] = nFileLength; Jqzw94  
} 2ih}?
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} Syseiw  
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q{V e%8$"  
//启动子线程 /t`|3Mw  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ..Dm@m}  
for(int i=0;i<nStartPos.length;i++) /&\V6=jA1  
{ Pm#/j;  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), )a0l:jEOc  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ;HAvor=?  
nStartPos,nEndPos,i); Q\zaa9P  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); %7-(c  
fileSplitterFetch.start(); ;ZuHv {=  
} xtCMK1# x  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), J;<dO7j5  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); fn/?I\  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ,){#
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nEndPos = " + nFileLength); X*MK(aV3  
// fileSplitterFetch[nPos.length-1].start(); Z^Um\f  
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//等待子线程结束 s[a\m,  
//int count = 0; G0m$bi=z  
//是否结束while循环 4S*ifl  
boolean breakWhile = false; v6DjNyg<x  
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while(!bStop) 74N_>1!j  
{ S@!_{da  
write_nPos(); q{G8Po$z'  
Utility.sleep(500); }fk3a9j9u  
breakWhile = true; gFuK/]gzI  
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for(int i=0;i<nStartPos.length;i++) @C^x&Sjm  
{ SVZ@'X\[M  
if(!fileSplitterFetch.bDownOver) F#yn'j8  
{ Pc&dU1  
breakWhile = false; X]9<1[f  
break; lH?jqp
  
} q{}5wM  
} 3]'ab-,Vp  
if(breakWhile) 2.</n}g  
break; zOA~<fhT  
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P<Z` 8a[  
//count++; &ZMQ]'&  
//if(count>4) |wJdp,q R  
// siteStop(); i`f!)1  
} G6{'|CV  
}D!tB  
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System.err.println("文件下载结束！"); 7bbFUUUG"  
} HCrQ+r{g  
catch(Exception e){e.printStackTrace ();} LUxDP#~7  
} CAviP61T  
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//获得文件长度 uWClT):  
public long getFileSize() JFc,f  
{ &/Gn
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int nFileLength = -1; F (kq  
try{ F{QOu0$cA4  
URL url = new URL(siteInfoBean.getSSiteURL()); "0nsYE  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); AH/^v;-  
httpConnection.setRequestProperty("User-Agent","NetFox"); [?:MIl#!  
!_3b#Caf  
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int responseCode=httpConnection.getResponseCode();
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if(responseCode>=400) q9_AL8_  
{ C7R3W,  
processErrorCode(responseCode); I6;6x  
return -2; //-2 represent access is error yKrbGK*=_  
} BI%~0Gj8  
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String sHeader; *k#"@  
f*"T]AX0  
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for(int i=1;;i++) XM+.Hel  
{ i"n_oO  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 0+1!-
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//Utility.log(in.readLine()); Xu~N97\G  
sHeader=httpConnection.getHeaderFieldKey(i); L?;UcCB  
if(sHeader!=null) Kyk{:UnI  
{ G"m0[|XH  
if(sHeader.equals("Content-Length")) oB!Y)f6H1  
{ UkD\ma  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); [O^/"Qk  
break; T=~d.&J  
} /N%i6t<xU  
} li?@BHEf  
else +\%]<YO  
break; ox<&T|  
} 2G-"HOG  
} /kyO,g$9  
catch(IOException e){e.printStackTrace ();} H;_Ce'oU(  
catch(Exception e){e.printStackTrace ();} 6W1+@ q  
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Utility.log(nFileLength); 4qE4 i:b  
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return nFileLength; V.$tq  
} urkuG4cY  
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//保存下载信息（文件指针位置） 2`;XcY4A  
private void write_nPos() 1}c/l<d  
{ *2~WP'~PQd  
try{ mE{QTZS  
output = new DataOutputStream(new FileOutputStream(tmpFile)); H[s+.&^  
output.writeInt(nStartPos.length); T?[;ej:  
for(int i=0;i<nStartPos.length;i++) vOCaru?~h  
{ mX.mX70|J  
// output.writeLong(nPos); Bca$%3
M  
output.writeLong(fileSplitterFetch.nStartPos); @}Ry7H0O  
output.writeLong(fileSplitterFetch.nEndPos); |6?s?tC"u  
} xc@$z*w  
output.close(); d>I)_05t  
} NTZ3Np`  
catch(IOException e){e.printStackTrace ();} kq(
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catch(Exception e){e.printStackTrace ();} F~E)w5?\O  
} <G<5)$ S  
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//读取保存的下载信息（文件指针位置） :ln|n6X  
private void read_nPos() Z R=[@Oi  
{ 2uT6M%OC  
try{ UE5,Ml~X  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ;xw9#.d#D  
int nCount = input.readInt(); _~CJitR3  
nStartPos = new long[nCount]; z8S]FpM6  
nEndPos = new long[nCount]; Z/:
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for(int i=0;i<nStartPos.length;i++) E Lq1   
{ ;c]O*\/  
nStartPos = input.readLong(); 6
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nEndPos = input.readLong(); ]Oo!>iTQi  
} :epB:r  
input.close(); p`7d9MV^  
} ]<YS7.pT  
catch(IOException e){e.printStackTrace ();} q Sv!5&u  
catch(Exception e){e.printStackTrace ();} r9bAbE bI  
} C_ d|2C6  
aw lq/
 
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private void processErrorCode(int nErrorCode) ND?
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{ E]&N'+T
 
System.err.println("Error Code : " + nErrorCode); %nq<nfDT  
} 2P'Vp7f6 Y  
:+QNN<  
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//停止文件下载 s/J7z$NEU  
public void siteStop() $
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{ tAep_GR  
bStop = true; T>1#SWQ/9  
for(int i=0;i<nStartPos.length;i++) @V^.eVM\R  
fileSplitterFetch.splitterStop(); 3j$,L(  
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} P%yL{  
}  Jn|<G  
//负责部分文件的抓取 ^9hc`.5N&?  
**FileSplitterFetch.java -*w2<DCn  
*/ q3/4l%"X
 
package NetFox; yr>J^Et%_  
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import java.io.*; x~Z7p)D_<  
import java.net.*; HES$.a  
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public class FileSplitterFetch extends Thread { |p+FIr+  
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String sURL; //File URL 1z2v[S&pk  
long nStartPos; //File Snippet Start Position IN1n^f$:  
long nEndPos; //File Snippet End Position #2Q%sE?  
int nThreadID; //Thread's ID rs>,p)  
boolean bDownOver = false; //Downing is over g]44|9x(W  
boolean bStop = false; //Stop identical !U(S?:hvW  
FileAccessI fileAccessI = null; //File Access interface hV`?, ~K  
hF^JSCDz l  
>zJkG9a  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ;XZN0A2  
{ B$JPE7h@[P  
this.sURL = sURL; 9dszn^]T  
this.nStartPos = nStart; mqJD+ K  
this.nEndPos = nEnd; `'r]Oe  
nThreadID = id; JF}i=}
 
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ?Y\WSI?i  
} g9g ]X  
J'=s25OWU  
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public void run() ]moBVRd  
{ p\'X%R  
while(nStartPos < nEndPos && !bStop) d@JavcR  
{ gV':Xe  
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try{ $`0^E#Nl  
URL url = new URL(sURL); FChW`b&S  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); xk8NX-:  
httpConnection.setRequestProperty("User-Agent","NetFox"); G;t<dJ8  
String sProperty = "bytes="+nStartPos+"-"; ]+qd|}^  
httpConnection.setRequestProperty("RANGE",sProperty); g_tEUaiK  
Utility.log(sProperty); p'
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InputStream input = httpConnection.getInputStream();  L=!h`k  
//logResponseHead(httpConnection); <$uDN].T4  
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byte[] b = new byte[1024]; Y@ ;/Sf$Q  
int nRead; qB
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while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) |4aU&OX  
{
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nStartPos += fileAccessI.write(b,0,nRead); 9 s2z=^  
//if(nThreadID == 1) FRPdfo37  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 6,~ %  
} id`9,IJx  
5 8U
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Utility.log("Thread " + nThreadID + " is over!"); O6-';H:I]L  
bDownOver = true; 9ucoQ@  
//nPos = fileAccessI.write (b,0,nRead); $V<fJpA  
} $'*{&/
@  
catch(Exception e){e.printStackTrace ();} _Eq,udCso  
} 5
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} ~U8#yo  
9K&YHg:1  
\Z~@/OVc
  
//打印回应的头信息 tg/!=g  
public void logResponseHead(HttpURLConnection con) Uul5h8F  
{ Ix=(f0|  
for(int i=1;;i++) !]7L9TGn  
{ 3dtL[aV
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String header=con.getHeaderFieldKey(i); @WKJ7pt`'N  
if(header!=null) !,7)ZW?*8  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); r:U<cLT[9  
Utility.log(header+" : "+con.getHeaderField(header)); h;cw=G  
else KUq(&H7  
break; ^\VVx:]  
} ]nxSVKE4p  
} '2<N_)43$  
}b<w\9AF  
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public void splitterStop() X1u\si%.4S  
{ &,/-<y-S  
bStop = true; 1F2(MKOo!  
} j{ri]?p  
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v]q"{c/  
} O6q5qA  
VF<VyWFC0`  
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/* \)g}  
**FileAccess.java iNL>TVUM  
*//文件访问(定位，写)  ? EhIK  
package NetFox; ="g9>  
import java.io.*; KC<K*UHPAH  
>dDc
m  
P!&yYR\  
public class FileAccessI implements Serializable{ ,;h}<("q  
X4bZ4U*  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ?*QL;[n1  
RandomAccessFile oSavedFile; b^P
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long nPos; |gGD3H  
Q'^$;X~-<  
~!Rf5QA85  
public FileAccessI() throws IOException b|.<rV'BTt  
{ B-$ps=G+z  
this("",0); }qhND-9#@  
} OR10IS  
"@xL9[d  
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public FileAccessI(String sName,long nPos) throws IOException W=K+kB  
{ sg<
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oSavedFile = new RandomAccessFile(sName,"rw"); a7z%)i;Z  
this.nPos = nPos; Nqj5,9*c  
oSavedFile.seek(nPos); w(odgD  
} z Hl+P*)  
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%LnG^L  
public synchronized int write(byte[] b,int nStart,int nLen) kxY9[#:<fB  
{ ( d8rfet  
int n = -1; `P*PCiZos  
try{ NQd0$q  
oSavedFile.write(b,nStart,nLen); \Dx)P[Ur  
n = nLen; v@:m8Y(t  
} 5lE9UoG[Q  
catch(IOException e) @`SlOKz!=  
{ 5%fR9?)  
e.printStackTrace (); "(;t`,F  
} ;Z&w"oSJ  
j|r$!gV  
'81WogH:  
return n; _E^ !,Wz  
} *Y ?&N2@c  
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} 1(a+|  
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%/K;!'7  
/* Mbxrj~ue  
**SiteInfoBean.java }pT>dbZ
  
*/ @.v{hkM`  
package NetFox; ].N%A07  
[ldx_+xa:E  
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public class SiteInfoBean { |OBZSk1jp  
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private String sSiteURL; //Site's URL pxQh;w  
private String sFilePath; //Saved File's Path 0(|36;x  
private String sFileName; //Saved File's Name )KN]"<jB  
private int nSplitter; //Count of Splited Downloading File h]
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public SiteInfoBean() ]7%+SH,RdD  
{//nSplitter的缺省值为5 -lI6!a^  
//default value of nSplitter is 5 $w! v  
this("","","",5); YM +4:P2  
} %uy?@e  
fSm|anuKZe  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) v,)vW5jGI  
{ SM
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sSiteURL= sURL; {mB &xz:b  
sFilePath = sPath; ;#dzw!+Y  
sFileName = sName; (=QiXX1r  
this.nSplitter = nSpiltter; G-R
E  
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} 22v= A6 =  
HVM(LHm=:  
NYF 7Ep; _  
public String getSSiteURL() 4]ETF+   
{ q<Wz9lDMNR  
return sSiteURL; [gE2;J0*  
} d>`s+B9K0  
Jgzg[6  
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public void setSSiteURL(String value) qfB!)Y  
{ Vg1MA  
sSiteURL = value; d)v'K5  
} :.F;LF&  
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public String getSFilePath() bB
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{ 2@$`xPg   
return sFilePath; r[kmgPld  
} 3rVWehCv  
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public void setSFilePath(String value) P&9&/0r=_  
{ k(3FT%p  
sFilePath = value; sKGR28e  
} \t']Lf  
bc*CP0t|  
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C  
public String getSFileName() FK`M+ j  
{ l=ZX9<3  
return sFileName; JReJlDu  
} } !RBH(m%  

8H2A<&3i  
a3E.rr;b  
public void setSFileName(String value) MDOP2y`2i  
{ +>o} R?xj  
sFileName = value; JI[9c,N  
} sGFC?1r?\  
OA8iTn  
aX(Y `g)|  
public int getNSplitter() OW1\@CC-69  
{ OmC F8:\/  
return nSplitter; \kVi&X=q:  
} R\n*O@E v3  
>R2o7~  
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public void setNSplitter(int nCount) 1A;f[Rze  
{ @N+6qO}  
nSplitter = nCount; XiN@$  
} _
6{XqvWqb  
} {x/)S*:Z  
=9cN{&qf  
Ox}a\B8  
/* J={IGA  
**Utility.java l*>,:y  
*/ SOo}}a0  
package NetFox; YV/JZc f  
RI-)Qx&!f  
?UV!^w@L:0  
public class Utility { g)Dg=3+>  
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'7/c7m/$X<  
public Utility() x"n)y1y  
{ &{H LYxh  
<&p0:S
7  
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} "o>gX'm*  
56^#x  
//线程睡眠 !Di*y$`}b  
public static void sleep(int nSecond) s!F` 0=J^  
{ 2]f?c%)I  
try{ EiWsVic[  
Thread.sleep(nSecond); .]H1uoci|  
} 2vx1M6a)L  
catch(Exception e) ! )PV-[2  
{ AWn$od`#s  
e.printStackTrace (); 4]%v%64U  
} },(Ln
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} 
~xV|<;  
Ym/y2B(  
//日志 0X[uXf  
public static void log(String sMsg) s2Hx
?~  
{ Z^SF $+UN  
System.err.println(sMsg); !_#2$J*s^D  
}  /DN!"  
2C_/T8  
*Z C$DW!-  
public static void log(int sMsg) Hlye:.$  
{ KJ;N
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System.err.println(sMsg); !Au9C   
} \rY<DxtOq  
} K"U[OZC`  
@Zov&01  
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/* ,CA3Q.y>|  
**TestMethod.java ]\Q9j7}37+  
*/ %+e% RZ3  
package NetFox; Or*e$uMIY  
.cA'6J"Bm\  
52>,JHq  
public class TestMethod { K~ShV  
{m
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mDJ
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public TestMethod() Xj("  
{ ///xx/weblogic60b2_win.exe JVk"M=c  
try{ -cW'g  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); dpWBY3(7a  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); +U];  
SiteFileFetch fileFetch = new SiteFileFetch(bean); {Wp5Ane  
fileFetch.start(); $MB/j6#j  
} /agX! E4s  
catch(Exception e){e.printStackTrace ();} l!^+Xeg~  
s`Z'5J;S  
v<c@bDZ>  
} d0MF\yxh  
kz+OUA@~  
;&v~tD7  
public static void main(String[] args) ri?>@i-9=  
{ uy^vQ/  
new TestMethod(); "o.g}Pv  
} p{BBqKv  
} FqT2+VO~  
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