http断点续传简单实现（java)

/* E 5kF^P  
**SiteFileFetch.java ( tn< VK.  
*/ \|+/0USn  
package NetFox; >[3X]n,0  
import java.io.*; uW[3G  
import java.net.*; oX|?:MS:  
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public class SiteFileFetch extends Thread { };SV!'9s?~  
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SiteInfoBean siteInfoBean = null; //文件信息Bean "3y}F  
long[] nStartPos; //开始位置 zl)&U=
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long[] nEndPos; //结束位置 YN#XmX%  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 sv=^k(d3  
long nFileLength; //文件长度 WN0c%kz=  
boolean bFirst = true; //是否第一次取文件 ;QPy:x3  
boolean bStop = false; //停止标志 f-+.;`H)T  
File tmpFile; //文件下载的临时信息 )Qr6/c8}  
DataOutputStream output; //输出到文件的输出流 h3 @s2 fK  
p{C9`wi)  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） _t.FL@3e  
public SiteFileFetch(SiteInfoBean bean) throws IOException fOBN=y6x  
{ %cj58zO|y  
siteInfoBean = bean; |\{Nfm=:%  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); R+Lk~X^*l'  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); >l2w
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if(tmpFile.exists ()) 5P\N"Yjx'  
{ _;G=G5r  
bFirst = false; tp+=0k2i  
read_nPos(); <IH*\q:7  
} /co%:}ln  
else j`9Nwa  
{ BTs0o&}e  
nStartPos = new long[bean.getNSplitter()]; "_)|8|gN  
nEndPos = new long[bean.getNSplitter()]; #JS`e_3Rr  
} SsRVd^=;x  
 1ZNNsB  
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} 9HKf^+';n  
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public void run() \^s2W:c  
{ ]wf|PU~nr  
//获得文件长度 u:5IjOb2^  
//分割文件 $3:X+X  
//实例FileSplitterFetch )[ b#g(Y(  
//启动FileSplitterFetch线程 @LC~*_y   
//等待子线程返回 UT;4U;a,m  
try{ ~
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if(bFirst) xppkLoPK  
{ %yhI;M^  
nFileLength = getFileSize(); >;}]pI0T  
if(nFileLength == -1) K P6PQgc  
{ LaT8l?q q  
System.err.println("File Length is not known!"); v>:=w|.HC  
} ?%;B`2 nDR  
else if(nFileLength == -2) L5C2ng>  
{ w .l|G,%=  
System.err.println("File is not access!"); o'^phlX  
} Z"N(=B  
else x_|>n<Z  
{ qOgtGN}k  
for(int i=0;i<nStartPos.length;i++) bQV("~#  
{  2$)mC9  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 1gk0l'.z  
} X#7}c5^Y  
for(int i=0;i<nEndPos.length-1;i++) PvuAg(?  
{ *k[kV  
nEndPos = nStartPos[i+1]; _Z.;u0Zp8  
} c.-cpFk^L&  
nEndPos[nEndPos.length-1] = nFileLength; .t:DvB  
} bN!u}DnN  
} \ %_)_"Q  
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//启动子线程 #~*XDWvIS~  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 6d};|
#}  
for(int i=0;i<nStartPos.length;i++) k%!VP=c4s  
{ v*XkWH5  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), uZ<%kV1B  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ,| <jjq)  
nStartPos,nEndPos,i); -[<vYxX:h:  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); K+-zY[3  
fileSplitterFetch.start(); N+hedF@ZU  
} *LEu=3lp%>  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), bkkSIl+Q  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); _y"a2M  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", p4y6R4kyT  
nEndPos = " + nFileLength); ]p\u$VY9  
// fileSplitterFetch[nPos.length-1].start(); 15JsmA*Q  
<B=[hk!  
_ flgQ  
//等待子线程结束 i<Q&
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//int count = 0; OMi02tSm  
//是否结束while循环 p&QmIX]BZ  
boolean breakWhile = false; W1;=J^<&1  
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while(!bStop) pOX$4$VR<  
{ eL_^: -   
write_nPos(); Jxf}b}^T  
Utility.sleep(500); %B0w~[!4}  
breakWhile = true; 1O23"o5=  
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for(int i=0;i<nStartPos.length;i++) &b!vWX1N  
{ L2<+#O#  
if(!fileSplitterFetch.bDownOver) Mc!2mE%47m  
{ ),MU+*`  
breakWhile = false; QYH."7X >  
break; tz"5+uuu  
} (;C$gnr.C  
} 2c"/QT  
if(breakWhile) '1Y<RD>x  
break; T<XfZZ)l<`  
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//count++; [#7D~Lx/  
//if(count>4) f!mE1,eBEe  
// siteStop(); ruzMag)  
} "-28[a3q  
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System.err.println("文件下载结束！"); $1b]xQ  
} ]&' jP  
catch(Exception e){e.printStackTrace ();} /i> ?i@O-  
} %7iUlO}}V  
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//获得文件长度 Z(l9>A7!  
public long getFileSize() %Fs*
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{ K?$9N}+  
int nFileLength = -1; a^%8QJW  
try{ i[o&z$JO  
URL url = new URL(siteInfoBean.getSSiteURL()); sN"p5p  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); /4(Z`e;0  
httpConnection.setRequestProperty("User-Agent","NetFox"); 'lxLnX  
}!eF
  
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int responseCode=httpConnection.getResponseCode(); !p-'t]  
if(responseCode>=400) 2;3x,<Cg  
{ M\9at\$  
processErrorCode(responseCode); l#tS.+B7  
return -2; //-2 represent access is error ?OdV1xB  
} UB5}i('L  
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String sHeader; {bW"~
_6}  
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for(int i=1;;i++) 7ytm.lU  
{ .L~fFns/  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); n'! -Pv  
//Utility.log(in.readLine()); O)Xd3w'  
sHeader=httpConnection.getHeaderFieldKey(i); k,a,h^{}j  
if(sHeader!=null) Lr K9F^c  
{ "1_{c *ck  
if(sHeader.equals("Content-Length")) yW%&_s0  
{ >oVc5}  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); czXI?]gg,  
break; <+ -V5O^  
} 7^n,Tig  
} &*X3
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else (PRaiE  
break; z\X60T  
} H?rSP0.  
} cZPbD;e:  
catch(IOException e){e.printStackTrace ();} cjCE3V9X  
catch(Exception e){e.printStackTrace ();} zG&WWc`K  
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Utility.log(nFileLength); bv.EM  
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return nFileLength; ;:v]NZtc  
} Q,[rrG;?@  
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#N<s^KYG-  
//保存下载信息（文件指针位置） }T?i%l  
private void write_nPos() >:3xi{  
{ e-nWD  
try{ (2\li{$e  
output = new DataOutputStream(new FileOutputStream(tmpFile)); `=_7I?  
output.writeInt(nStartPos.length); 0L3Bo3:k  
for(int i=0;i<nStartPos.length;i++) gubb .EY  
{ =YS!soO  
// output.writeLong(nPos);
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output.writeLong(fileSplitterFetch.nStartPos); s98: *o3  
output.writeLong(fileSplitterFetch.nEndPos); D<+ bzC  
} E#yCcC!wMY  
output.close(); [X0k{FR  
} uYG #c(lc  
catch(IOException e){e.printStackTrace ();} )_Z]=5Ds  
catch(Exception e){e.printStackTrace ();} BsoFQw4$9  
} Y2RxD\!Z  
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//读取保存的下载信息（文件指针位置） 9'L1KQ  
private void read_nPos() ^N*pIVLC  
{ |HKHN?)  
try{ 8cYuzt]..  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); z6GL,wo#  
int nCount = input.readInt(); ~$ cm9>  
nStartPos = new long[nCount]; C=xo&I7  
nEndPos = new long[nCount]; A"P\4  
for(int i=0;i<nStartPos.length;i++) 842Mydom  
{ E9~&f^f  
nStartPos = input.readLong(); ;Xnk+  
nEndPos = input.readLong(); f~n' Ki+'  
} RW|UQY#  
input.close(); Yke<Wy1  
} {[(W4NAlH  
catch(IOException e){e.printStackTrace ();} \t&n jMWpZ  
catch(Exception e){e.printStackTrace ();} r9p?@P\:[  
} -o!saX<  
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private void processErrorCode(int nErrorCode) \?5[RR  
{ *g/I&'^  
System.err.println("Error Code : " + nErrorCode); ND)M3qp2(  
} YyX^lL_  
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[A.eVuV;+  
//停止文件下载 Rx_,J%0Fq  
public void siteStop() rm7*l<v6  
{ 'tq\<y
 
bStop = true; M8^ziZY  
for(int i=0;i<nStartPos.length;i++) )[^:]}%r
 
fileSplitterFetch.splitterStop(); ThT.iD[  
(
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} #=)?s 8T
 
} P~b%;*m}8  
//负责部分文件的抓取 vl#V-UW$4P  
**FileSplitterFetch.java DbPBgD>Q  
*/ r&j+;JM5  
package NetFox; YV2pERl  
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*`\4j*$^  
import java.io.*; 0*]<RM  
import java.net.*; qZyt>SAx  
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public class FileSplitterFetch extends Thread { IAt+S-q0  
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rsq'60  
String sURL; //File URL T^f&58{ 7  
long nStartPos; //File Snippet Start Position ] BP^.N=  
long nEndPos; //File Snippet End Position !Cv<>_N).  
int nThreadID; //Thread's ID [8om9 Z3  
boolean bDownOver = false; //Downing is over BhhK|U/  
boolean bStop = false; //Stop identical ;r2b@x:<_  
FileAccessI fileAccessI = null; //File Access interface CM@"l
V_  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException i >/@]2  
{ st1M.}  
this.sURL = sURL; r(/P||`l  
this.nStartPos = nStart; $7k04e@]  
this.nEndPos = nEnd; QVA!z##  
nThreadID = id; M\$<g  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 }!J/ 9WKgU  
} .,iw2:  
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public void run() PHB\)/  
{ )Sh;UW  
while(nStartPos < nEndPos && !bStop) Qg8eq_m(  
{ U%SNROj  
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try{ iaq:5||,  
URL url = new URL(sURL); ES:p^/=*  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); *^&iw$Qx3  
httpConnection.setRequestProperty("User-Agent","NetFox"); Q=9VuTE  
String sProperty = "bytes="+nStartPos+"-"; ,"HpV  
httpConnection.setRequestProperty("RANGE",sProperty); n B|C-.F  
Utility.log(sProperty); ;tIIEc  
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InputStream input = httpConnection.getInputStream(); E`Zh\u)  
//logResponseHead(httpConnection); )="g?E3  
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byte[] b = new byte[1024]; }e;p8)]Wl  
int nRead; 9"l%tq_  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 9ixnf=$Jp  
{ Zq6ebj  
nStartPos += fileAccessI.write(b,0,nRead); @rDv (W  
//if(nThreadID == 1) {
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// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); N'1[t  
} ,hcBiL/  
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Utility.log("Thread " + nThreadID + " is over!"); kv`3Y0R-"  
bDownOver = true; R|
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//nPos = fileAccessI.write (b,0,nRead); VE+p&0  
} xdSj+507  
catch(Exception e){e.printStackTrace ();} iOA3x 8J  
} v+, w{~7RH  
} {gq:sj>  
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//打印回应的头信息 vN[m5)aT  
public void logResponseHead(HttpURLConnection con) @x\gk5  
{ (4/`@;[  
for(int i=1;;i++) P24  
{ [+5SEr}  
String header=con.getHeaderFieldKey(i); k@X As  
if(header!=null) [O =)FiY-  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); "q#g/T  
Utility.log(header+" : "+con.getHeaderField(header)); yyYbB]D  
else s</ktPtu  
break; iS^^Z ZyR  
} dYttse'  
} 1 bx^Pt)  
dXr !_)
i  
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public void splitterStop() PfMOc+ q  
{ NhaeAD $e  
bStop = true; % w/1Uo24  
} r:b.>5CS)  
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}
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/* LHGK!zI  
**FileAccess.java XwqfWd
_  
*//文件访问(定位，写) (%^TTe  
package NetFox; !N2 n@bo  
import java.io.*; <Ucfd G&Lp  
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public class FileAccessI implements Serializable{ ;Z0cD*Jb  
j-\^ }K.&  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 +=F);;!  
RandomAccessFile oSavedFile; oA^ ]x>  
long nPos; JL+[1=uE1L  
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public FileAccessI() throws IOException 5+PBS)pJ]%  
{ /VOST^z!  
this("",0); RAJ|#I1  
} Kwmo)|7uPU  
;bu;t#  
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public FileAccessI(String sName,long nPos) throws IOException sjbC~Te--  
{ eT \Q  
oSavedFile = new RandomAccessFile(sName,"rw"); olW`.3f  
this.nPos = nPos; #hiDZ>nr  
oSavedFile.seek(nPos); %y~]3XWik  
} h.0&)t\q"  
0hr)tYW,G  
LGue=Hkp  
public synchronized int write(byte[] b,int nStart,int nLen) &Fr68HNmj  
{ fXR_)d  
int n = -1; )=y6s^}  
try{ |Szr=[  
oSavedFile.write(b,nStart,nLen); \d8=*Zpz7  
n = nLen; oEf^o*5(  
} $XzlW=3y  
catch(IOException e) Qpu2RfP  
{ {@`Uf;hPAX  
e.printStackTrace (); (4gQe6tA  
} :re(khZq#  
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return n; eyp\h8!u_  
} @Pg@ltUd  
#8HXR3L5=!  
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} Or~6t}f  
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U-N/
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/* b-gVRf#F  
**SiteInfoBean.java Ol
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*/ fu;B?mIn  
package NetFox; -s84/E4Y*  
/1@m#ZxA:  
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public class SiteInfoBean { vWga>IGM  
LU=)\U@Q  
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private String sSiteURL; //Site's URL Z1}zf(JU  
private String sFilePath; //Saved File's Path ooxzM `  
private String sFileName; //Saved File's Name _^A NJ7  
private int nSplitter; //Count of Splited Downloading File _Pm}]Y:_  
`^Sq>R!;  
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public SiteInfoBean() meWq9:z  
{//nSplitter的缺省值为5
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//default value of nSplitter is 5 QAw,XZ.K^  
this("","","",5); lt"*y.%@b  
} [l{e
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) c3BL2>c  
{
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sSiteURL= sURL;
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sFilePath = sPath; 1Ac1CsK*  
sFileName = sName; g0$k_  
this.nSplitter = nSpiltter; f@g  
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} CR=MjmH  
%P6!vx:&^b  
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public String getSSiteURL() +5
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{ ,_-*/- 7;8  
return sSiteURL; d8I:F9  
} ]jrxrUl  
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public void setSSiteURL(String value) .`RC,R`C  
{ %05a>Rf&  
sSiteURL = value; _L.yt5_  
} v%Xe)D   
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public String getSFilePath() e@By@r&nql  
{ %j; cXN  
return sFilePath; G-<~I#k  
} aC` c^'5  
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public void setSFilePath(String value) C_)>VPD  
{ iB-s*b<`~  
sFilePath = value;  K>eG5tt  
} 1=.?KAXR  
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public String getSFileName() ?8/h3xV;  
{ _\[G7  
return sFileName; ,oil}N(  
} /L^dHI]Q  
}5Uf`pM8  
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public void setSFileName(String value) dG+xr!  
{ *
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sFileName = value; zBfBYhS-  
} [t
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//|Vj | =  
public int getNSplitter() Hq$|j,&?  
{ 2T9Z{v  
return nSplitter; vS#]RW&j  
} :P~Owz  
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w (1a{m?ht  
public void setNSplitter(int nCount) >d\I*"C+d  
{ kvn6 NiU  
nSplitter = nCount; 470Pig>I8  
} <i-RF-*S  
} sn%fE  
*Yw6UCO  
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/* wxxC&
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**Utility.java WTx;,TNG  
*/ L8Q!6oO=<  
package NetFox; Y`uCDfcQ  
(Bz(KyD[  
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public class Utility { 3}+ \&[  
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public Utility() 1wt]J!hgV  
{ X*Zv,Wm  
$)!Z"2T  
r^)<Jy0|r  
} =B1!em|  
;Lu|fQ#u*  
//线程睡眠 \BW(c)Q  
public static void sleep(int nSecond) QR4o j  
{ M;R>]wP"V  
try{ Tx_LH"8  
Thread.sleep(nSecond); 7Z_iQ1  
} )SuJK.IF  
catch(Exception e) 3]acfCacC  
{ VbjW$?  
e.printStackTrace (); p WHu[Fu  
} .anL}OA_q  
} uHYI :(O  
q`hg@uwA{`  
//日志 wlJ1,)n^2  
public static void log(String sMsg) #A!0KN;GC2  
{ cf9y0  
System.err.println(sMsg); {;U:0BPI3  
} Nsq%b?#  
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p  
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public static void log(int sMsg) ^&Bye?`5  
{ _17"T0  
System.err.println(sMsg); mD!i
mq%=  
} _ sd?l  
} CfU)+20  
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/* 6c:$[owC  
**TestMethod.java ?9:\1)]  
*/ ?jbam!A  
package NetFox; W2RS G~|  
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public class TestMethod { jolCR-FDu  
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im
\  
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public TestMethod() $1e@3mzM  
{ ///xx/weblogic60b2_win.exe H\T h4teE  
try{ `8I&(k<wLe  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ?4_;9MkN  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); _[x(p6Xp  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ?k#%AM  
fileFetch.start(); qF?S[Z;  
} <qBPN{'a"  
catch(Exception e){e.printStackTrace ();} dZ*o H#
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} pmC@ fB  
vd~O:=)4  
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public static void main(String[] args) =GF+hM/~  
{ deNU[  
new TestMethod(); wP%;9y2B  
} <:?&}'aA  
} X*T9`]l6  
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