http断点续传简单实现（java)

/* +=.W<b
 
**SiteFileFetch.java A@sZ14+f  
*/ V}SBuQp"  
package NetFox; <K8\n^i~c  
import java.io.*; wyQzM6:,yX  
import java.net.*; OujCb^Rm  
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public class SiteFileFetch extends Thread { qUOKB6
 
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SiteInfoBean siteInfoBean = null; //文件信息Bean VxXzAeM  
long[] nStartPos; //开始位置 ]Yvga!S"C  
long[] nEndPos; //结束位置 H<}^'#"p  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ;uW}`Q
<  
long nFileLength; //文件长度 tPGJ<30  
boolean bFirst = true; //是否第一次取文件 rwG CUo6Z  
boolean bStop = false; //停止标志 86\S?=J-b  
File tmpFile; //文件下载的临时信息 U)o$WH.b  
DataOutputStream output; //输出到文件的输出流 U )l,'y2  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） Fm #w2o  
public SiteFileFetch(SiteInfoBean bean) throws IOException JM\m)RH0  
{ r%.do;5  
siteInfoBean = bean; sRrzp=D  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 9M1d%jT  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); "sl1vzRN  
if(tmpFile.exists ()) 7g(F#T?;'  
{ o4zM)\;F  
bFirst = false; 4y5UkU9|  
read_nPos(); )JNSZB  
} Ldl5zc  
else y!!E\b=  
{ E Kz'&Gu  
nStartPos = new long[bean.getNSplitter()]; ^pe{b9c  
nEndPos = new long[bean.getNSplitter()]; +{L<? "  
} YBP:q2H  
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} D*YM[sN`  
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public void run() i7utKj*57  
{ bLd#xXl  
//获得文件长度 X0M1(BJgGo  
//分割文件 SJ};TEA  
//实例FileSplitterFetch vJU*>U,  
//启动FileSplitterFetch线程 K a(J52  
//等待子线程返回 lME)?LOI  
try{ /M*a,o  
if(bFirst) zdEPDdB  
{ }LijnHH.  
nFileLength = getFileSize(); LI6hEcM=  
if(nFileLength == -1) Wf&W^Q  
{ BZXUwqEh  
System.err.println("File Length is not known!"); =T7A]U]  
} 4)<~4 '  
else if(nFileLength == -2) (Gw,2-A  
{ }Iz7l{al  
System.err.println("File is not access!"); _+^ 2^TW  
} S9>0t0  
else acw4
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{ 3,Q^& 1  
for(int i=0;i<nStartPos.length;i++) #zRbx  
{ ?
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); q=DN {a:  
} h'$9C  
for(int i=0;i<nEndPos.length-1;i++) &09U@uc$  
{ lZrVY+D  
nEndPos = nStartPos[i+1]; YTjkPj:  
} W":PG68  
nEndPos[nEndPos.length-1] = nFileLength; `St.+6^J  
} fS"Hr0  
} v,\R,{0  
+\{
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//启动子线程 WMBm6?54  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; `r_m+
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for(int i=0;i<nStartPos.length;i++) k~|-gfFP  
{  =Mb1o[  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), (}
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), h#hxOVl%x  
nStartPos,nEndPos,i);
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Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); I6s3+x;O  
fileSplitterFetch.start(); &V<W>Y>|l*  
} 7oR:1DXw|  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ) 9oH,gZ  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); )#}mH@  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", KPpHwcYxT  
nEndPos = " + nFileLength); DtEwW
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// fileSplitterFetch[nPos.length-1].start(); $L2%u8}8:  
nxJee=qH  
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//等待子线程结束 B=@ jWz"  
//int count = 0; bLnrbid  
//是否结束while循环 PccB]  
boolean breakWhile = false; hG_?8:W8HT  
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while(!bStop) 7lo|dg80  
{ QERU5|.wc  
write_nPos(); F>X-w+b4r  
Utility.sleep(500); 5&f{1M6l>  
breakWhile = true; +~ #U7xgq/  
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for(int i=0;i<nStartPos.length;i++) 62>zt2=  
{ P\&! ]  
if(!fileSplitterFetch.bDownOver) KHDZ  
{ 8p!*?RRme[  
breakWhile = false; D
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break; tdF9NFMD  
} QQpP#F|w  
} L}yyaM)  
if(breakWhile) gBf4's  
break; 8V-\e?&^  
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//count++; +]@Az.E  
//if(count>4) lI/0:|l  
// siteStop(); 7DfTfTU6  
} "W#t;;9Wz  
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}N*>QR5K  
System.err.println("文件下载结束！"); L@^~N$G&u  
} =ORf%f5"'  
catch(Exception e){e.printStackTrace ();} "|m|E/Z-9  
} ZCg`z
  
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Cj*-[EL<  
//获得文件长度 dtAbc7
 
public long getFileSize() SxjCwX">  
{ ./p|?pu  
int nFileLength = -1; do-c1;M  
try{ CWO=0_>2  
URL url = new URL(siteInfoBean.getSSiteURL()); mga6[E<  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Se!)n;?7Sw  
httpConnection.setRequestProperty("User-Agent","NetFox"); Fn^C{p^  
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- /c7nF  
int responseCode=httpConnection.getResponseCode(); %k0EpJE%  
if(responseCode>=400) dS`Bk6Y  
{ X[W]=yJJ  
processErrorCode(responseCode); ]=!P
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return -2; //-2 represent access is error k?VQi5M  
} V5D`eX9  
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String sHeader; M"_FrIO  
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for(int i=1;;i++) <TNk?df7  
{ ^\:2}4Uj_  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); jvzBh-!  
//Utility.log(in.readLine()); * \HRw +cL  
sHeader=httpConnection.getHeaderFieldKey(i); ;:m&#YJV  
if(sHeader!=null) M)cGz$Q|  
{ /dDzZ%/@  
if(sHeader.equals("Content-Length")) Yn9j-`  
{ A.Bk/N1G  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); IwpbfZ  
break; Qeb}!k2A  
} &D#+6M&LK{  
} +[m8c){  
else iQ^: ])m>  
break; 89cVJ4]g~!  
} !~
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} ,PWj_}|L[  
catch(IOException e){e.printStackTrace ();} *wi}>_\  
catch(Exception e){e.printStackTrace ();} Q;nAPS  
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Utility.log(nFileLength); +ySY>`1k~  

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return nFileLength; 0p fnV%  
} cbKL$|  
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//保存下载信息（文件指针位置） &k T"oK  
private void write_nPos() Y(GN4@`S  
{ |xr32gs  
try{ i9UI,b%X  
output = new DataOutputStream(new FileOutputStream(tmpFile)); LNQSb4  
output.writeInt(nStartPos.length); wUi(3g|A  
for(int i=0;i<nStartPos.length;i++) sa1mC  
{ 30FykNh  
// output.writeLong(nPos); ,2WH/"  
output.writeLong(fileSplitterFetch.nStartPos); m%QqmTH  
output.writeLong(fileSplitterFetch.nEndPos); |ia@,*KD  
}
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output.close(); .V%*{eHLL  
} >kdM:MK  
catch(IOException e){e.printStackTrace ();} OR+A_:c.D  
catch(Exception e){e.printStackTrace ();} C]`eH*z~8  
} /hdf{4  
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//读取保存的下载信息（文件指针位置） "7?js $  
private void read_nPos() OoP@-D"e  
{ MB:n~>ga  
try{ M@?"t_e1  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Q:S\0cI0  
int nCount = input.readInt(); )-&nxOP  
nStartPos = new long[nCount]; >,h1N$A+  
nEndPos = new long[nCount]; s?O&ZB2GM[  
for(int i=0;i<nStartPos.length;i++) b?kPN:U#N/  
{ ]5|z3<K^  
nStartPos = input.readLong(); Goj4`Hc  
nEndPos = input.readLong(); j$eCe<.3  
} gJ\%>r7h  
input.close(); Ugi5OKdj7)  
} ~HP LV  
catch(IOException e){e.printStackTrace ();} eX<K5K.B  
catch(Exception e){e.printStackTrace ();} wsg//Ec]  
} FU@uH U5fd  
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private void processErrorCode(int nErrorCode) U($^E}I2(  
{ L? ;/cO^  
System.err.println("Error Code : " + nErrorCode); ,0T)Oc|HL/  
} o_yRn16  
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//停止文件下载 NyJnO
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public void siteStop() 4/L>&%8V  
{ umDtp\  
bStop = true; *1;23BiH-  
for(int i=0;i<nStartPos.length;i++) #J+\DhDEPO  
fileSplitterFetch.splitterStop(); uFe'$vI  
/!bx`cKG  
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} R^9"N?Q7;`  
} ,o&<WMD  
//负责部分文件的抓取 96W4c]NT  
**FileSplitterFetch.java md6*c./Z  
*/ 3%NE/lw1  
package NetFox; K<,Y^3]6?  
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import java.io.*; Dy
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import java.net.*; $DV-Ieb  
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public class FileSplitterFetch extends Thread { '?R=
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String sURL; //File URL ^"`Z1)V  
long nStartPos; //File Snippet Start Position (^S5Sc=  
long nEndPos; //File Snippet End Position `9EVB;  
int nThreadID; //Thread's ID L;C|ow^c  
boolean bDownOver = false; //Downing is over _z:Qhe  
boolean bStop = false; //Stop identical $Z7:#cZ Y  
FileAccessI fileAccessI = null; //File Access interface |B1Af  
!?r/ 4  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Ao!=um5D J  
{ -eYL*P
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this.sURL = sURL; nE<J`Wo$f  
this.nStartPos = nStart; RQ5P}A 3H  
this.nEndPos = nEnd; K|~AA"I;  
nThreadID = id; jmPp-}tS7  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 S%V%!803!  
} nB}e1 /_y  
/a%KS3>V*  
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public void run() ZX]
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{ -$tCF>,  
while(nStartPos < nEndPos && !bStop) F=5kF/}x-z  
{ Ko-QR(  
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try{ coO.kTO;  
URL url = new URL(sURL); ULbP_y>(Y  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); #x|VfN5f  
httpConnection.setRequestProperty("User-Agent","NetFox"); MZiF];OY  
String sProperty = "bytes="+nStartPos+"-"; GsRt5?X/*  
httpConnection.setRequestProperty("RANGE",sProperty); 7?]!Ecr"  
Utility.log(sProperty); P59uALi  
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InputStream input = httpConnection.getInputStream(); `L">"V`$Bj  
//logResponseHead(httpConnection); /]l f>\x1  
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byte[] b = new byte[1024]; 5YLho2h38!  
int nRead; 5z[6rT=a  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 7\ZL  
{ .n=xbx:=  
nStartPos += fileAccessI.write(b,0,nRead); tJG (*  
//if(nThreadID == 1) hf[IEK  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); "#J}A0  
} ^1vq{/ X  
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;lkf+,;  
Utility.log("Thread " + nThreadID + " is over!"); 6%z`)d  
bDownOver = true; rOhA*_EG  
//nPos = fileAccessI.write (b,0,nRead); nO%<;-=u\  
}
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catch(Exception e){e.printStackTrace ();} )rS^F<C  
} 2PI #ie4  
} b__n~\q_  
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//打印回应的头信息 `ITDTZ J  
public void logResponseHead(HttpURLConnection con) 34]%d<
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{ _]Z$YM  
for(int i=1;;i++) 1(D1}fcul  
{ q2D`1nT  
String header=con.getHeaderFieldKey(i); SaTEZ.  
if(header!=null) 7~ILRj5Nq  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); \J\vp0[nO}  
Utility.log(header+" : "+con.getHeaderField(header)); g<;Nio  
else r$Kh3EEF`E  
break; rufRaar  
} 8Q+TE;  
} :hi$}xHa  
'fXer!L}  
F}\[eFf[  
public void splitterStop() d!FONi  
{ jeyaT^F(   
bStop = true; Psg +\14  
} N/`g?B[  
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} oF`-cyj"  
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/* baA HP"  
**FileAccess.java V}p*HB@:  
*//文件访问(定位，写) 9n-RXVL+  
package NetFox; <`^>bv9  
import java.io.*; FP0<-9DO  
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public class FileAccessI implements Serializable{ VK"[=l  
oM m/!Dc  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ]ZBgE\[  
RandomAccessFile oSavedFile; r(748Qc4f?  
long nPos; ,2Sv1v$  
\0xzBs1!  
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public FileAccessI() throws IOException oo"JMD)  
{ us(sZG  
this("",0); Nj"_sA p  
} ZzSJm+&'  
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public FileAccessI(String sName,long nPos) throws IOException P1vF{e  
{ axt6u)4%7:  
oSavedFile = new RandomAccessFile(sName,"rw"); k0Oc,P`'*  
this.nPos = nPos; Va&KIHw  
oSavedFile.seek(nPos); m
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} zhD`\&G.  
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ZzwZ,(  
public synchronized int write(byte[] b,int nStart,int nLen) 9~*_(yjF  
{ r5<e}t-  
int n = -1; zcbA)
  
try{ 9;'>\ImI  
oSavedFile.write(b,nStart,nLen); J:k@U42  
n = nLen; 4?*`:  
} ]*t*/j;N  
catch(IOException e) [7CH(o1a&  
{ as\)S?0`.  
e.printStackTrace (); t~udfOvY  
} =iPd@f"$  
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^[SbV^DOL  
return n; F\YcSDM  
} gs)%.k[BqG  
8O}A/*1FJ  
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} ~gcst;  
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/* p>w~T#17  
**SiteInfoBean.java jn#N7%{Mk  
*/ M2;(+8 b  
package NetFox; 8EVF<@{]  
/(z0I.yE  
'44nk(hM69  
public class SiteInfoBean { lMI ix0sSj  
{{#a%O  
}rb ]d'|  
private String sSiteURL; //Site's URL 4YB7og%P  
private String sFilePath; //Saved File's Path CgPZvB[  
private String sFileName; //Saved File's Name `)xU;-  
private int nSplitter; //Count of Splited Downloading File %i JU)N!  
kAKqW7,q"  
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public SiteInfoBean() LQ&d|giA  
{//nSplitter的缺省值为5  *
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//default value of nSplitter is 5 1V?Sj
  
this("","","",5); FZ'>LZ  
} C.TCDl  
bQnwi?2  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 7;#dX~>@{  
{ 1rzq$,O  
sSiteURL= sURL; "Jv,QTIcS  
sFilePath = sPath; `peJ s~V  
sFileName = sName; @|*Z0bn'  
this.nSplitter = nSpiltter; 9@&Z`b_  
}'M1(W  
>c'_xa?^G  
} K5c7>I%k  
s }R:
q  
*R~(:z>>  
public String getSSiteURL() Q`wA"mw6k  
{ MZ+IorZl  
return sSiteURL; b<H6D}  
} HjY-b*B  
(NWN&  
0 VgnN
  
public void setSSiteURL(String value) 06W=(fY  
{ YKS'#F2  
sSiteURL = value; $@f3=NJ4k  
} mUY:S |  
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Q Fqv,B\<  
public String getSFilePath() !Z2n;.w  
{ #dm@%~B{.  
return sFilePath; 7VZ JGRnn  
} s&_O2
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<rI$"=7  
7G=P|T\  
public void setSFilePath(String value) 4uVmhjT:X  
{ =y(YMWGS  
sFilePath = value; >^ 1S2
6  
} pnw4QQ9  
<T% hfW
 
nv[Sb%/  
public String getSFileName() $0C/S5b  
{ xla^A}{  
return sFileName; $YQ&\[pDA  
} X@4d~6k?  
$u.T1v  
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public void setSFileName(String value) p. ~jo  
{ PC7.+;1  
sFileName = value; TS8E9#1a  
} dw}3B8]  
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U)1qsUDF  
public int getNSplitter() Llc|j&yHQ  
{ aC]l({-0  
return nSplitter; M<m64{m1  
} Xz@;`>8i  
EUS]Se2  
!VTS $nJ4  
public void setNSplitter(int nCount) 3n)iTSU3  
{ =w?cp}HW  
nSplitter = nCount; Elk$9 <<  
} H#`?toS  
} I}A#*iD
 
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`IQC\DSl/  
/* <aD+Ki6  
**Utility.java Ri0+nJ6  
*/ M_)T=s *  
package NetFox; P[oB'  
&4iIzw`  
*Yjs$'_2  
public class Utility { F RUt}*  
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En_8H[<%  
public Utility() b4PK  
{ tR/ J
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%LW~oI.  
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} lv&wp@  
3A
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//线程睡眠 5Ozj&Zq  
public static void sleep(int nSecond) (o=iX,@'2  
{ _{);n$`  
try{ \MPy"uC  
Thread.sleep(nSecond); w$H
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} 7w({ GZ  
catch(Exception e) @L7rE)AU.  
{ /UAj]U  
e.printStackTrace (); 5G[^ah<Tg  
} $a1.c;NE'  
} Z)0R$j`2  
!4fL|0  
//日志 )[.URp&  
public static void log(String sMsg) pqX=l%{4ES  
{ v4^VYi,.-  
System.err.println(sMsg); c5u?\  
} ;[ojwcK[ZF  
~Q\[b%>J  
Yr@@ty  
public static void log(int sMsg) d4tVK0 ~  
{ =*N(8j>y
 
System.err.println(sMsg); E2cmT$6  
} WX9BS$}0  
} \!Pm^FD .  
)JON&~C  
IYPI5qCR  
/* [;
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**TestMethod.java 7EUaf;d^  
*/ Ft7l/  
package NetFox; :a2?K5  
i=rW{0c%  
PT=%]o]  
public class TestMethod { :mL.Y em*'  
J<D =\  
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public TestMethod() 8[V!e[  
{ ///xx/weblogic60b2_win.exe iZF{9@  
try{ A2 rRYzN;  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 2*N# %ZUX  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); "wc $'7M  
SiteFileFetch fileFetch = new SiteFileFetch(bean); e5Z\v0  
fileFetch.start(); &x}JC/u]fd  
} LBzpaLd  
catch(Exception e){e.printStackTrace ();} 0td;Ag  
GU9
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} 5 ,HNb
 
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GZo^0U,;  
public static void main(String[] args) o3yZCz  
{ S<44{ oH  
new TestMethod(); pc #^{-  
} `|4{|X*U.  
} - >2ej4C  
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