http断点续传简单实现（java)

/*  Hi#hf"V  
**SiteFileFetch.java X-=49)  
*/ >HyZ~M  
package NetFox; "d%o%  
import java.io.*; W2'u]1bs  
import java.net.*; N^v"n*M0|  
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public class SiteFileFetch extends Thread { UZz/v#y~  
';Y0qitGB  
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SiteInfoBean siteInfoBean = null; //文件信息Bean !ap}+_IA7^  
long[] nStartPos; //开始位置 9!;/+P  
long[] nEndPos; //结束位置 1N,</<"  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ]V^ >aUlj  
long nFileLength; //文件长度 `p#tx.o  
boolean bFirst = true; //是否第一次取文件 a[I :^S  
boolean bStop = false; //停止标志 $i1$nc8  
File tmpFile; //文件下载的临时信息 ?L x*MJZ  
DataOutputStream output; //输出到文件的输出流 shKTj5s?  
}2
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） id+ ~ V  
public SiteFileFetch(SiteInfoBean bean) throws IOException 4 Fl>XM  
{ F$M^}vsjGx  
siteInfoBean = bean; !Ah v07SI  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); HAwdu1$8  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); nvbzCtC  
if(tmpFile.exists ()) u.;l=tzz  
{ i]9C"Kw$L  
bFirst = false; {>g{+Eq  
read_nPos(); Y \Gx|  
} Np7+g`nG  
else 2DUY4Ti  
{ 'hR0JXy  
nStartPos = new long[bean.getNSplitter()]; jh(T?t$&  
nEndPos = new long[bean.getNSplitter()]; $7"
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} C~Hhi-Xl)  
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} {8>g?4Q#  
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public void run() [;H-HpBaa  
{ R:4@a ':H  
//获得文件长度 JkhWLQ>o  
//分割文件 i-PK59VZ8f  
//实例FileSplitterFetch Bv<aB(c  
//启动FileSplitterFetch线程 Qk? WX (`B  
//等待子线程返回 1w~PHH`~  
try{ 9U8x&Z]P  
if(bFirst) 3\2%i6W6  
{ @R%*;)*F  
nFileLength = getFileSize(); ,OWk[
0/  
if(nFileLength == -1) f0vO(@I  
{ .fbY2b([  
System.err.println("File Length is not known!"); ^s6}[LDW>@  
}  9u^M{6  
else if(nFileLength == -2) "
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{ {CV+1kz  
System.err.println("File is not access!"); M!+
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} ^3
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else NB1KsvD{  
{ b"WF]x|^  
for(int i=0;i<nStartPos.length;i++) Q7rBc wm5  
{ MA,*$BgZ  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); U$mDAi$  
} 6#7hMQ0&;O  
for(int i=0;i<nEndPos.length-1;i++) yUj`vu2  
{ >ei~:z]R  
nEndPos = nStartPos[i+1]; k:I,$"y4  
} JcUU#>  
nEndPos[nEndPos.length-1] = nFileLength; T?Kh'  
} g3].STz6w  
} ]L97k(:Ib  
]f#s`.A~  
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//启动子线程 XHekz
6_  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; QuqznYSY{  
for(int i=0;i<nStartPos.length;i++) GA[Ebzi  
{ '{cSWa| #  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), @oE 5JM  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ?OLd }8y  
nStartPos,nEndPos,i); ]R_R`X?  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); x>}ml\R  
fileSplitterFetch.start(); gzIx!sc  
} 'g!T${  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), K_;vqi^1^&  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ?D6uviQg  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", `wXK&R<`  
nEndPos = " + nFileLength); :ZM9lBYh  
// fileSplitterFetch[nPos.length-1].start(); uR ?W|a  
(iX
8YP$%  
:D*U4
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//等待子线程结束 ux<|8S  
//int count = 0; l)9IgJ|<b  
//是否结束while循环 . :Skc  
boolean breakWhile = false; eCYPd-d  
5Jbwl$mZ  
iX$G($[l(  
while(!bStop) SI=$s>1  
{ ,B[j{sE  
write_nPos(); <{isWEW9]3  
Utility.sleep(500); !?nbB2,  
breakWhile = true; TI'v /=;)  
2)n`Bd  
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for(int i=0;i<nStartPos.length;i++) cD0rU8x  
{ (-gomn  
if(!fileSplitterFetch.bDownOver) M76p=*  
{ CIx(SeEF  
breakWhile = false; t>[W]%op  
break; I8Aq8XBw  
} lI<jYd 0fZ  
} Nap[=[rv  
if(breakWhile) }|.<EkA  
break; &BRk<iwV  
<rBW6o7  
e$Ksn_wEq  
//count++; 6kYluV+j  
//if(count>4) ,^:{!?v  
// siteStop(); suY47DCX)  
} .
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UIC  
+<a\0FsD  
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System.err.println("文件下载结束！"); xDo0bR(  
} lU{)%4e`  
catch(Exception e){e.printStackTrace ();} 5(+9a   
} =Hg!@5]H  
<T}^:2G|  
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//获得文件长度 ek][^^4o  
public long getFileSize() w:5?ofC  
{ V$?6%\M^*  
int nFileLength = -1; qYK^S4L  
try{ /j~~S'sw  
URL url = new URL(siteInfoBean.getSSiteURL()); csy6_q(  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ?2]fE[SqY  
httpConnection.setRequestProperty("User-Agent","NetFox"); \Y4(+t=4  
ui%#f1Iq
 
}J#HIE\RG  
int responseCode=httpConnection.getResponseCode(); OG5{oH#K  
if(responseCode>=400) q3x"9i `  
{ e$[O J<t  
processErrorCode(responseCode); Nx 42k|8  
return -2; //-2 represent access is error Uu_qy(4  
} i!a!qE.1  
if*V-$[I  
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String sHeader; Z>g72I%X  
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for(int i=1;;i++) //&3{B  
{ D_l$"35?  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); `i`P}W!F  
//Utility.log(in.readLine()); Wd'}YbC  
sHeader=httpConnection.getHeaderFieldKey(i); 'gY?=,dF>  
if(sHeader!=null) o@)Fy51DD  
{ G<CD4:V  
if(sHeader.equals("Content-Length")) d]E=w6+;Q  
{ Zz0er|9]Q  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); y4kn2Mw;  
break; 9C7Npf?~M  
} ntIR#fB  
} v?He]e'  
else y3efie {J  
break; OC&BJNOi  
} -C2!`/
U  
} 5Ew( 0K[  
catch(IOException e){e.printStackTrace ();} z};|.N}  
catch(Exception e){e.printStackTrace ();} )7.)fY$  

=
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Utility.log(nFileLength); X5o*8Bg4M  
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return nFileLength; lf-.c$.>  
} g[~{iu_$d  
ndFVP;q  
G&h@   
//保存下载信息（文件指针位置） oaj.5hM  
private void write_nPos() :Quep-:fy<  
{ Wrp~OF0k  
try{ nReIi;pi  
output = new DataOutputStream(new FileOutputStream(tmpFile)); VP!4Nob  
output.writeInt(nStartPos.length); 4rDVCXE  
for(int i=0;i<nStartPos.length;i++) T'6`A<`3  
{ 6?xF!VIL  
// output.writeLong(nPos); ;8<HB1 &,  
output.writeLong(fileSplitterFetch.nStartPos); 6D| F1UFU  
output.writeLong(fileSplitterFetch.nEndPos); 4Q!
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} %f<>Kwr`2  
output.close(); GJWGT`"  
} '9QEG
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catch(IOException e){e.printStackTrace ();} N4x5!00  
catch(Exception e){e.printStackTrace ();} ^Zvb3RJg  
} jUD^]
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//读取保存的下载信息（文件指针位置） 8AW}7.<5  
private void read_nPos() Rk5#5R n  
{ t<dFH}U`w  
try{ 4Q#{,y944  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); i+(>w'=m  
int nCount = input.readInt(); }J?,?>Z  
nStartPos = new long[nCount]; 7#wB  
nEndPos = new long[nCount]; 5`3x(=b  
for(int i=0;i<nStartPos.length;i++) HT/!+#W.  
{ @_t=0Rc  
nStartPos = input.readLong(); [PN
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nEndPos = input.readLong(); --diG$x.  
} A3.I|/  
input.close(); )^8[({r~  
} HPu+ 4xQV  
catch(IOException e){e.printStackTrace ();} y=sae  
catch(Exception e){e.printStackTrace ();} }Tk:?U{  
} 0Sk~m4fj(  
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private void processErrorCode(int nErrorCode) [f\Jcjc  
{ pq
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System.err.println("Error Code : " + nErrorCode); J;<dO7j5  
} t]Ln(r  
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//停止文件下载 B#
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public void siteStop() "c} en[  
{ LK4NNZf7  
bStop = true; >l
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for(int i=0;i<nStartPos.length;i++) '4d4i  
fileSplitterFetch.splitterStop(); W%5))R$  
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[>>_%T\I  
} #5h_{q4l  
} @C^x&Sjm  
//负责部分文件的抓取 A",}Ikh='`  
**FileSplitterFetch.java "*/IP9?]  
*/ `%~
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package NetFox; 5nBJj  
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import java.io.*; _'Jjt9@S  
import java.net.*; MCTJ^g"D  
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public class FileSplitterFetch extends Thread { 3n)Kzexh  
9;I%Dv  
\:s%;s51  
String sURL; //File URL \VEnP=*:W  
long nStartPos; //File Snippet Start Position %'g)MK!e  
long nEndPos; //File Snippet End Position 2gklGDJD  
int nThreadID; //Thread's ID |15!D  
boolean bDownOver = false; //Downing is over AH/^v;-  
boolean bStop = false; //Stop identical vO$cF*  
FileAccessI fileAccessI = null; //File Access interface 49>b]f,Vc  
#%ld~dgz-  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException raOu
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{ fBZLWfp9  
this.sURL = sURL; "CC"J(&a  
this.nStartPos = nStart; V:j^!*  
this.nEndPos = nEnd; LHx ")H?,  
nThreadID = id; fsK=]~<g  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Dz$w6d  
} 0+qC_ISns  
:4 z\Q]  
]!!?gnPd5  
public void run() KyT=:f V  
{ /N%i6t<xU  
while(nStartPos < nEndPos && !bStop) 
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{ U!Zj%H1XQ0  
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try{ jyF*JQjK4  
URL url = new URL(sURL); e(^I.`9z  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); _3%:m||,XP  
httpConnection.setRequestProperty("User-Agent","NetFox"); !hfpa_5  
String sProperty = "bytes="+nStartPos+"-"; )lt1I\n*k  
httpConnection.setRequestProperty("RANGE",sProperty); "1a!]45+  
Utility.log(sProperty); 1}c/l<d  
S-\wX.`R1  
'l!\2Wv2  
InputStream input = httpConnection.getInputStream(); \WnTpl>B  
//logResponseHead(httpConnection); s&o9LdL  
4P)#\$d:  
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byte[] b = new byte[1024]; =$bF[3D  
int nRead; >Ho=L)u  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) =AzkE]  
{ 'l\PL1  
nStartPos += fileAccessI.write(b,0,nRead); n2-+.9cY  
//if(nThreadID == 1) %=
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// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 2+)h!y]  
} ;xw9#.d#D  
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Utility.log("Thread " + nThreadID + " is over!"); d)biMI}<5  
bDownOver = true; u=s,bt,"5  
//nPos = fileAccessI.write (b,0,nRead); !wd wo0  
} e~)4v  
catch(Exception e){e.printStackTrace ();} q Sv!5&u  
} g%]<sRl:-  
} 2P`./1L  
+?3RC$jyw  
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//打印回应的头信息 "WGKwi=W  
public void logResponseHead(HttpURLConnection con) .WN&]yr,  
{ s/J7z$NEU  
for(int i=1;;i++) 7=X6_AD  
{ T>1#SWQ/9  
String header=con.getHeaderFieldKey(i); iKu3'jZ/O  
if(header!=null) S=V  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); P%yL{  
Utility.log(header+" : "+con.getHeaderField(header)); Yyd}>+|<,  
else AIQ {^:  
break; RWM~7^JA  
} G.XxlI}  
} ;}S_PnwC@  
}0H<G0  
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public void splitterStop() 1#"wfiW  
{ 7u^wO<  
bStop = true; ,mCf{V]#  
} F:<+}{Av  
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} buzpmRoN)  
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<)O#Y76s  
/* V?^qW#AG  
**FileAccess.java JF}i=}
 
*//文件访问(定位，写) }mZCQJ#`  
package NetFox; @g#| srYD  
import java.io.*; (kK8 OxfF  
Fv/{)H<:y  
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public class FileAccessI implements Serializable{ :Zq?V`+M  
Edh9=sxL  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 V5h_uGOD  
RandomAccessFile oSavedFile; c??m9=OX1  
long nPos; 30Q77,Nsny  
9_&]7ABV  
@*op5qVw  
public FileAccessI() throws IOException %(?;`  
{ E:\#Ur2  
this("",0); +ZE"pA^C  
} ],R\oMYy|P  
9 s2z=^  
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public FileAccessI(String sName,long nPos) throws IOException id`9,IJx  
{ TK>~)hc}  
oSavedFile = new RandomAccessFile(sName,"rw"); 4T)`%Oo<}  
this.nPos = nPos; v,rKuvc'  
oSavedFile.seek(nPos); |z}VP-L  
} <7ag=IgDy  
9K&YHg:1  
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public synchronized int write(byte[] b,int nStart,int nLen) Uul5h8F  
{ y?}<SnjP:  
int n = -1; mSFA i  
try{ "x_G6JE4tv  
oSavedFile.write(b,nStart,nLen); VeFfkg4  
n = nLen; KUq(&H7  
} pwVGe|h%,  
catch(IOException e) pnv)D}"  
{ NZ^hp\q  
e.printStackTrace (); YB{'L +Wbw  
} 9I1`*0A  
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return n; AQ"r
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} mI^S%HT  
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\/Zo*/  
} UD2l!)rW  
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/* ronZa0  
**SiteInfoBean.java @GQtyl;q  
*/ .36]>8  
package NetFox; 1l}fX}5%I;  
u@4khN: ^p  
6*tky;  
public class SiteInfoBean { OR10IS  
(gutDUO;  
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private String sSiteURL; //Site's URL d&DQ8Gm ^  
private String sFilePath; //Saved File's Path ]6WP;.[  
private String sFileName; //Saved File's Name .  
private int nSplitter; //Count of Splited Downloading File 'L%)B-,n  
4"+v:t)z6{  
y(**F8>?xE  
public SiteInfoBean() Ige*tOv2  
{//nSplitter的缺省值为5 )Y=ti~?M(  
//default value of nSplitter is 5 4_ZHY?VRd  
this("","","",5); drB$q[Ak9  
} '^:q|h  
P`n"E8"ab<  
//
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ;'4Kg@/  
{ `6*1mE1K&  
sSiteURL= sURL; sFRQFX0XoY  
sFilePath = sPath; kl5Y{![/&f  
sFileName = sName; H<3ayp$  
this.nSplitter = nSpiltter; 7}Jn`^!  
ENZYrWl  
#\O?|bN'q  
} ]ex2c{ G  
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public String getSSiteURL()  9E  
{ 8ao>]5Rs3  
return sSiteURL; ^ Mq8jw(2  
} J/A UOInh  
']>/$[!  
5S%#3YHY2  
public void setSSiteURL(String value) V_H0z  
{ vsbD>`I  
sSiteURL = value; e:iqv?2t  
} +2^Mz&I@b  
@?[}\9dW  
I- WR6s=  
public String getSFilePath() x^!LA,`j  
{ FmtV[C#  
return sFilePath; E"t79dD  
} )9V8&,  
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public void setSFilePath(String value) gib;> nuBK  
{ C +S>;1  
sFilePath = value; 2~W8tv0^b2  
} _!E/em  
d
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public String getSFileName() o<i\1<eI  
{ "v5jYz5M  
return sFileName; 43o!Vr/S  
} PQ4)k
VT  
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:LX (9f   
public void setSFileName(String value) &l(PWU  
{ C4t@;U=x  
sFileName = value; vo]$[Cp|4  
} 1<&nHFJ;[  
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public int getNSplitter() APL #-`XC  
{ !1ZrS  
return nSplitter; +p_>fO  
} $|!@$Aj  
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1A;f[Rze  
public void setNSplitter(int nCount) Nd61ns(N  
{ JAP4Vwj%j  
nSplitter = nCount; .V\:)\<|  
} ttA0* >'  
} !ZTBiC5R  
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/* j+QE~L  
**Utility.java Sv|jR r'  
*/ !d3:`l<  
package NetFox; Qwu~{tf+'  
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public class Utility { ,l
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{{ /-v3n  
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public Utility() 
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{ ! )PV-[2  
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} 8:)itYE  
k&SI-jxj  
//线程睡眠 Z^SF $+UN  
public static void sleep(int nSecond) a C<  
{ Q=Y1kcTOn  
try{ ^Y- S"Ks  
Thread.sleep(nSecond); !Au9C   
} $g+q;Y~i0  
catch(Exception e) :ZP`Y%dt'
 
{ ,CA3Q.y>|  
e.printStackTrace (); _vgFcE~E@  
} j9]H~:g$d  
} <m!(eLm+B  
DQRr(r~2Kj  
//日志 |$aTJ9 Iq:  
public static void log(String sMsg) 9$oU6#U,h  
{ bQ6<R4  
System.err.println(sMsg); t (>}  
} +U];  
 (:ObxJ*  
$wx)/t<  
public static void log(int sMsg) H|i39XV  
{ "<5su5]  
System.err.println(sMsg); |'" 17c&  
} SBynu  
} HHU0Nku@ho  
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/* S
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**TestMethod.java l
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*/ 4OOH 3O  
package NetFox; bQFMg41*w7  
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x."/+/  
public class TestMethod { 4C
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Ug1n4X3FKn  
d5O_~xf&  
public TestMethod() <B%s9Zy  
{ ///xx/weblogic60b2_win.exe ExDv7St1(k  
try{ jx7b$x]  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 6*]g~)7`Q~  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); $x'p+&n\  
SiteFileFetch fileFetch = new SiteFileFetch(bean); D#I^;Xg0h  
fileFetch.start(); _R 6+bB$  
} 7eyVm;LQD  
catch(Exception e){e.printStackTrace ();} 71GyMtX   
&+v!mw>  
WK<:(vu.  
} ;I^+u0ga  
SL O~  
iE;D_m.>`O  
public static void main(String[] args) m\hzQ9  
{ /P>t3E2c  
new TestMethod(); :4V8Iz 71  
} SZhW)0  
} I\DH  
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