http断点续传简单实现（java)

/* [~3[Tu( C  
**SiteFileFetch.java Lro[ |A  
*/ B3+9G,or  
package NetFox; $+ z3  
import java.io.*; Q]JWWKt6rV  
import java.net.*; aG"j9A~ &  
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public class SiteFileFetch extends Thread { rq>}] U  
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SiteInfoBean siteInfoBean = null; //文件信息Bean Jy#c
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long[] nStartPos; //开始位置 dRdI('  
long[] nEndPos; //结束位置 wzXIEWJ  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ?QDHEC62  
long nFileLength; //文件长度 Dq [f  
boolean bFirst = true; //是否第一次取文件 F@8G,$  
boolean bStop = false; //停止标志 N('=qp9  
File tmpFile; //文件下载的临时信息 JPH! .@  
DataOutputStream output; //输出到文件的输出流  Re=()M  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） k? <.y
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public SiteFileFetch(SiteInfoBean bean) throws IOException !lVOZ%  
{ _Sq*m=  
siteInfoBean = bean; ?/M:  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ;u+k!wn  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info");  x7<2K(  
if(tmpFile.exists ()) .wU0F  
{ .tdaj6x  
bFirst = false; |rU?  
read_nPos(); CPW^pGT+i  
} $U_M|Xa  
else y%Q0* _  
{ AiP#wK;  
nStartPos = new long[bean.getNSplitter()]; ww}4  
nEndPos = new long[bean.getNSplitter()]; t5| }0ID-  
} S/itK3  
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} kB)u@`</mV  
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public void run() l&/V4V-  
{ GM~Ek]9C%  
//获得文件长度 xU1_L*tu '  
//分割文件 |rgp(;iO  
//实例FileSplitterFetch tJM#/yT  
//启动FileSplitterFetch线程 =bBV A0y  
//等待子线程返回 "
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try{ !K8Kw W|X  
if(bFirst) 9{GEq@`7  
{ _o52#Q4   
nFileLength = getFileSize(); %(uYYr 6  
if(nFileLength == -1) xekU2u}WE  
{ V0l"tr@  
System.err.println("File Length is not known!"); -;:.+1  
} K7 J RCLA  
else if(nFileLength == -2) 2 rFjYx8D!  
{ 6e;POW  
System.err.println("File is not access!"); t/wo G9N  
} qkM)zOZ^  
else g@O H,h/  
{ E0*KKo%  
for(int i=0;i<nStartPos.length;i++) q4EOI  
{ :`>$B?x+  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); k-Z:z?M  
} f7SMO-3a  
for(int i=0;i<nEndPos.length-1;i++) e7S
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{ "5!T-Z+F  
nEndPos = nStartPos[i+1]; +a'LdEp  
} Ol sX  
nEndPos[nEndPos.length-1] = nFileLength;
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} [  *~2Ts  
} 45,):U5  
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qs%UJ0tR  
//启动子线程 :#VdFMC<  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; >T#" Im-  
for(int i=0;i<nStartPos.length;i++) !X[P)/?b0+  
{ ,Y4>$:#n/  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), UhKd o  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), d=p=eUd2  
nStartPos,nEndPos,i); Nz77" kC  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); dq{+-XaEk  
fileSplitterFetch.start(); )H>?K0I  
} Kqz+:E8D  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), @<jm+f"MP  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); j"A<qI  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", l$&dTI<#  
nEndPos = " + nFileLength); Y3\EX  
// fileSplitterFetch[nPos.length-1].start(); s&4&\Aq}x#  
LVNA`|>  
nWes,K6T  
//等待子线程结束 iYf)FPET  
//int count = 0; 
#Dea$  
//是否结束while循环 fm^J-  
boolean breakWhile = false; wVq9t|V  
8:;]tt  
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while(!bStop) i-}Tt<^  
{ TILH[r&Jg  
write_nPos(); I 6'!b/  
Utility.sleep(500); p/qu4[Mm  
breakWhile = true; xi<yB0MoA  
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for(int i=0;i<nStartPos.length;i++) 1=h5Z3/fj  
{ KO\-|#3y>  
if(!fileSplitterFetch.bDownOver) ~: fSD
0  
{ Ou4 `#7FR  
breakWhile = false; 4wN5x[vp  
break; AtUtE#K  
} ~>H,~</`  
} o-o -'0l  
if(breakWhile) ?t/G@  
break; `TYC]9  
~"\WV4}`v  
#~m8zG  
//count++; Qr_0 L  
//if(count>4) e"%uOuIYX  
// siteStop(); I)kc[/^j$  
} =A*a9c2  

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System.err.println("文件下载结束！"); )}7X4g6X   
} A>8~deZ9  
catch(Exception e){e.printStackTrace ();} g=KvCqJN  
} `fOp>S^Q4  
8`wKq6
 
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//获得文件长度 UpPl-jeT  
public long getFileSize() ZWni5uF-c  
{ O')=]6CQ*  
int nFileLength = -1; h;#0
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try{ 5UJ ?1"J  
URL url = new URL(siteInfoBean.getSSiteURL()); J(K/z,4h  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); \*&?o51!e  
httpConnection.setRequestProperty("User-Agent","NetFox"); /1p5KVTKv  
6<9}>Wkf  
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int responseCode=httpConnection.getResponseCode(); @u`W(Ow  
if(responseCode>=400) U[2;Fkapi  
{ wwRPfr[  
processErrorCode(responseCode); eso-{W,D  
return -2; //-2 represent access is error ($!uBF-b  
} "TP~TjXfq  
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String sHeader; 5 1N/XEk  
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for(int i=1;;i++) Qv`: E   
{ P*B@it  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 2 6DX4  
//Utility.log(in.readLine()); Hj(K*z  
sHeader=httpConnection.getHeaderFieldKey(i); c|(J%@B)  
if(sHeader!=null) Caz5q|Oo  
{ d#XgO5eyO  
if(sHeader.equals("Content-Length")) yMu G? x+  
{ (7N!Jvg9  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); i=*H|)  
break; >tPf.xI|l  
} {8qcM8  
} 1Jdx#K  
else >kxRsiKV  
break; U?d I  
} g4Q' Fub+I  
} P(FlU]q  
catch(IOException e){e.printStackTrace ();} 5|~nX8>  
catch(Exception e){e.printStackTrace ();} 6K )K%a,9  
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Utility.log(nFileLength); XI|k,Ko<  
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return nFileLength; :4-,Ru1C"  
}
+Adk1N8  
,*dLE   
N UvVhy]{  
//保存下载信息（文件指针位置） #
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private void write_nPos() _WvVF*Q"k  
{ J}[[tl  
try{ maDWV&Db  
output = new DataOutputStream(new FileOutputStream(tmpFile)); FNuE-_  
output.writeInt(nStartPos.length); y2#"\5dC  
for(int i=0;i<nStartPos.length;i++) 0;@>jo6,!  
{ k7Qs#L  
// output.writeLong(nPos); (_!I2"Q*  
output.writeLong(fileSplitterFetch.nStartPos); 9) ,|h  
output.writeLong(fileSplitterFetch.nEndPos); {aq)Y>o5:T  
} #R:&Irh  
output.close(); m<)`@6a/
 
} +p63J  
catch(IOException e){e.printStackTrace ();} 9Bw#VQ  
catch(Exception e){e.printStackTrace ();} (CRx'R  
} j5Da53c#^  
4_iA<}>|  
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//读取保存的下载信息（文件指针位置） AX$r,KmE  
private void read_nPos() q?Csm\
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{ Axns

  
try{ S<NK!89  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); akt7rnt?i  
int nCount = input.readInt(); hrq% {!Z  
nStartPos = new long[nCount]; \?R#ZxP@  
nEndPos = new long[nCount]; EnlAgL']|  
for(int i=0;i<nStartPos.length;i++) :H3/+/x  
{ i0$*):b  
nStartPos = input.readLong(); Q.$Rhjb  
nEndPos = input.readLong(); jc)7FE  
} Ky"FL  
input.close(); ,dT
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} tuIZYp8tIN  
catch(IOException e){e.printStackTrace ();} ,pI9=e@O/z  
catch(Exception e){e.printStackTrace ();} ohqThl  
} $l"%o9ICG  
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private void processErrorCode(int nErrorCode) R'`'q1=R  
{ {pH#zs4Y  
System.err.println("Error Code : " + nErrorCode); *E
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} ~WTkX(\  
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//停止文件下载 {icTfPR4E  
public void siteStop() ~a[/l  
{ bA,Zfsr6#  
bStop = true; {R-o8N  
for(int i=0;i<nStartPos.length;i++) O+|C<;K  
fileSplitterFetch.splitterStop(); n<j+KD#a  
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} 6];3h>c]N  
} KS93v9|  
//负责部分文件的抓取 3sdL\  
**FileSplitterFetch.java qE[YZ(/f0&  
*/ Uzzm2OS`  
package NetFox; s$>n U  
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s  
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import java.io.*; X>=`l)ZR  
import java.net.*; K2yNIq_  
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public class FileSplitterFetch extends Thread { ^@AyC"K  
-)oUb=Lk{  
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String sURL; //File URL }' AY#g  
long nStartPos; //File Snippet Start Position ; $80}TY '  
long nEndPos; //File Snippet End Position EZ .3Z`
 
int nThreadID; //Thread's ID )S%t)}  
boolean bDownOver = false; //Downing is over iBAP,cR?`  
boolean bStop = false; //Stop identical z``wqK  
FileAccessI fileAccessI = null; //File Access interface /m"/#; ^l  
<A)M^,#o  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException B F<u3p??  
{ `"&Nw,C  
this.sURL = sURL; A_oZSUrR  
this.nStartPos = nStart; $xZ ~bE9  
this.nEndPos = nEnd; Pn OWQ8=  
nThreadID = id; `L`+`B  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 &;d N:F;  
} gx9Os2Z|3  
:}v-+eIQ  
;C$+8%P4  
public void run() i>YQ<A1  
{ K#wA ;  
while(nStartPos < nEndPos && !bStop) }p
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{ e9KD mX_  
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try{ '^_u5Y]  
URL url = new URL(sURL); 7:
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); hOAZvrfQ4  
httpConnection.setRequestProperty("User-Agent","NetFox"); ALTOi?  
String sProperty = "bytes="+nStartPos+"-"; +_i{4Iz~p  
httpConnection.setRequestProperty("RANGE",sProperty); N~O
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Utility.log(sProperty); dn- [Gnde  
f<@!{y2Xe  
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InputStream input = httpConnection.getInputStream(); ?x #K:a?  
//logResponseHead(httpConnection); zW%Em81Wd  
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byte[] b = new byte[1024]; Re8x!e'>  
int nRead; !Rl|o^Vw>{  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) NAvR^"I~  
{ !|&|%x6@  
nStartPos += fileAccessI.write(b,0,nRead); *tF~CG$r  
//if(nThreadID == 1) wL?Up>fr  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); v&YeQC>  
} ( *+'k1Ea  
2P"9m  
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Utility.log("Thread " + nThreadID + " is over!"); =WY'n l'  
bDownOver = true; 1z-.e$&z  
//nPos = fileAccessI.write (b,0,nRead); o?Hfxp0}  
} +;q\7*  
catch(Exception e){e.printStackTrace ();} ResU5Ce~  
} _ Ncbo#G  
} sh$-}1 ;  
%)JEYH7Z  
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//打印回应的头信息 13!@LbC  
public void logResponseHead(HttpURLConnection con) }~I!'J#)  
{ yQ[;y~W  
for(int i=1;;i++) I$xZV?d.  
{ /IUu-/ D  
String header=con.getHeaderFieldKey(i); )Fv.eIBY  
if(header!=null)  l!|c_  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); J2W-l{`r<  
Utility.log(header+" : "+con.getHeaderField(header)); ~:z.Xu5m  
else Pqomi!1  
break; p,fV .5q  
} Wm}c-GD  
} V^2_]VFj  
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+'?Qph6o,7  
public void splitterStop() {q0
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{ /sKL|]i=  
bStop = true; l/X_CM8y~  
} l'+3 6  
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} ii)#(b:V  
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/* ,&t+D-s<f  
**FileAccess.java O^@8Drg
c  
*//文件访问(定位，写) x4
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package NetFox; 7s|'NTp  
import java.io.*; I@'[>t  
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public class FileAccessI implements Serializable{ ANhtz1Fl  
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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 !/is+ xp  
RandomAccessFile oSavedFile; y7,fFUKl  
long nPos; p&<Ssc  

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public FileAccessI() throws IOException l76=6Vtb  
{ A5XMA|2_  
this("",0); c?A$Y?|9  
} v"bWVc~H  
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public FileAccessI(String sName,long nPos) throws IOException Z,).)y#B  
{ Ma^jy.  
oSavedFile = new RandomAccessFile(sName,"rw"); _\WR3Q!V  
this.nPos = nPos; ]at$ohS  
oSavedFile.seek(nPos); (g##wa)L  
} a1cX+{W  
|`T(:ZKXZ2  
CY1WT  
public synchronized int write(byte[] b,int nStart,int nLen)
+Iyyk02V  
{ r6DLShP-Ur  
int n = -1; j_8 YFz5  
try{ !vSI"$xd  
oSavedFile.write(b,nStart,nLen); B]rdgjz*  
n = nLen; s.2f'i+  
} smn
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catch(IOException e) MpCPY"WLL  
{ nQF&^1n  
e.printStackTrace (); Qd}n4KF\  
} @Kpm&vd(  
;vH2r~  
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return n; 8?yIixhw  
} .hT>a<  
O =Z}DGa+  
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} *[Hp&6f  
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/* jl,gqMn"V  
**SiteInfoBean.java /;`H )  
*/ E)v~kC}7.  
package NetFox; noZbsI4  
K.Xy:l*z  
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public class SiteInfoBean { :@L7RZ`_  
72<9xNcB!}  
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private String sSiteURL; //Site's URL BIx*t9wA  
private String sFilePath; //Saved File's Path t>bzo6cj  
private String sFileName; //Saved File's Name N1t4o~  
private int nSplitter; //Count of Splited Downloading File )&c2+Y@  
c2E /-n4K@  
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public SiteInfoBean() 4)8k?iC*  
{//nSplitter的缺省值为5 @cDB 7w\  
//default value of nSplitter is 5 fv;Q*; oC&  
this("","","",5);
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} c1H.v^Y5  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) f1'ByV'2  
{ uyj!$}4  
sSiteURL= sURL; XcJ5KTn  
sFilePath = sPath; pS?D~0Nb  
sFileName = sName; (XZ[-M7  
this.nSplitter = nSpiltter; GBz?$]6  
_J,**AZ~z  
uo:RNokjJ  
} E?w#$HS  

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public String getSSiteURL() @2Z|\ojJ  
{ iJ>=!Q  
return sSiteURL; +t7HlAXB#  
} IFLphm
5  
{j wv+6]U  
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public void setSSiteURL(String value) $Itmm/M  
{ "*lx9bvV_  
sSiteURL = value; ZU\$x<,  
} JsY,Q,D q  
}8O9WS  
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public String getSFilePath() L$ T2 bul  
{ ,EQ0""G!  
return sFilePath; }?m0bM  
} rZI63S  
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@rhS[^1wi+  
public void setSFilePath(String value) 1jC85^1Taq  
{ 5gz^3R|`f  
sFilePath = value; Q& [!+s:2J  
} H I9/  
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public String getSFileName() xU;SRB  
{ Ar%*NxX  
return sFileName; M6-uTmN:d  
} $QiMA,  
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U6JD^G=qR,  
public void setSFileName(String value) U]Q5};FK  
{ tB;PGk_6  
sFileName = value; ^gVQ6=z%  
} XfcYcN  
AbNr]w&pXC  
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public int getNSplitter() $1=7^v[U  
{ JuJW]E Q  
return nSplitter; Uw4iWcC  
} BA a:!p  
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public void setNSplitter(int nCount) 4K cEJlK5  
{ F=F84_+K  
nSplitter = nCount; ww|fqx?  
} ?>7\L'n=5I  
} 0A}XhX  
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/* 3Ei^WDJ  
**Utility.java W[jg+|  
*/ 0\i\G|5  
package NetFox; 6jpzyf=~  
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@<K<"`~H  
public class Utility { tGOJ4 =  
bWL!=  
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public Utility() ]Zb9F[  
{ yBK$2to~  
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} %LnLB  
>V.?XZ nt  
//线程睡眠 33%hZ`/>  
public static void sleep(int nSecond) b GSj?t9/  
{ wPI!i K@Ro  
try{ **P P  
Thread.sleep(nSecond); 14&|(M  
} {GtX:v#  
catch(Exception e) j*>]HNo&  
{ "OwM' n8  
e.printStackTrace (); :U\*4l
 
} |kmP#`P~  
} Jk{SlH3'  
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//日志 km>ZhsqD  
public static void log(String sMsg) /Ey%aA4v  
{ =U84*HAv  
System.err.println(sMsg); $`OyGeq"T  
} d/GSG%zB
 
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public static void log(int sMsg) C32*RNG?U  
{ f)vnm*&-  
System.err.println(sMsg); p#c41_?'e  
} YUSrZ9Yg  
} <=CABWO.  
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_"*vj-{-y  
/* |i B#   
**TestMethod.java 8Z}%,G*n  
*/ 3]S_w[Q4  
package NetFox; / 8O=3  
+M.BMS2A<l  
m +A4aQ9  
public class TestMethod { )E9c6'd  
O<fy^[r:`  
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public TestMethod() 1.%|Er 4  
{ ///xx/weblogic60b2_win.exe ]U@~vA#''  
try{ jhRr!  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); vo Et\H  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); yIiVhI?X  
SiteFileFetch fileFetch = new SiteFileFetch(bean); = 1veO0  
fileFetch.start(); RaLV@>jPm  
} Z<<=2Xl(  
catch(Exception e){e.printStackTrace ();} uPho|hDp  
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} !Th5x2  
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public static void main(String[] args) (k+*0.T&?  
{ 1q=Q/
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new TestMethod(); _{):w~zi  
} #P!<u Lc%  
} Sg%s\p]N_#  
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