http断点续传简单实现（java)

/* 2}9M7Z",2  
**SiteFileFetch.java %\1W0%w  
*/  %d0BQ|  
package NetFox; \ Ju7.3.  
import java.io.*; riSgb=7q9  
import java.net.*; l(Uwci  

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public class SiteFileFetch extends Thread { gq.l=xS  
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SiteInfoBean siteInfoBean = null; //文件信息Bean cJ'OqV F  
long[] nStartPos; //开始位置 55zy]|F"  
long[] nEndPos; //结束位置 -T>i5'2)  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ey`E E/WV  
long nFileLength; //文件长度 /Uni6O)oc  
boolean bFirst = true; //是否第一次取文件 4V'HPD>=V  
boolean bStop = false; //停止标志 T:*l+<?  
File tmpFile; //文件下载的临时信息 "6i3
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DataOutputStream output; //输出到文件的输出流 ,-SWrp
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） Bm+Ca:p%  
public SiteFileFetch(SiteInfoBean bean) throws IOException kK.[v'[>&  
{ Lv<vMIr  
siteInfoBean = bean; R|]n;*y  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); D/Py?<n-B  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); `ix&j8E22w  
if(tmpFile.exists ()) gCx#&aXS  
{ {n(/ c33  
bFirst = false; [=^Wj`;  
read_nPos(); V}Ce3wgvA  
} +77B656  
else D=}\]Krmay  
{ <sls1,  
nStartPos = new long[bean.getNSplitter()]; v4,Dt  
nEndPos = new long[bean.getNSplitter()]; +.QJZo_  
} L.:8qY  
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} ]#vi/6\J  
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public void run() l_Zx'm  
{ x kdC-S  
//获得文件长度 k`J|]99Wb  
//分割文件 T@a|*.V  
//实例FileSplitterFetch ~nApRC)0  
//启动FileSplitterFetch线程 `yO'-(@"gY  
//等待子线程返回 h=B= J  
try{ KtHkLYOCG  
if(bFirst) WWATG=  
{ MfO:BX@$  
nFileLength = getFileSize(); IL`=r6\  
if(nFileLength == -1) ER0B{b  
{ R[@}Lg7+v  
System.err.println("File Length is not known!"); fg4mP_  
} *D.Ajd.G  
else if(nFileLength == -2) ABcB-V4  
{ 2+ywl}9  
System.err.println("File is not access!"); "F[7b!>R  
} '.&Y)A6!  
else !s:e  
{ -gUp/#l1  
for(int i=0;i<nStartPos.length;i++) h J0U-m  
{ c3r`T{Kf  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); <>728;/C  
} d</F6aM\  
for(int i=0;i<nEndPos.length-1;i++) 5lM2nhlf'b  
{ o4wSt6gBcJ  
nEndPos = nStartPos[i+1]; W
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} X0REC%  
nEndPos[nEndPos.length-1] = nFileLength; U_l9CZ  
} X-#&]^d  
} 2=/-,kOL_  
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*QV"o{V  
//启动子线程 >H ?k0M`L  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 52zE -SY  
for(int i=0;i<nStartPos.length;i++) ZvMU3]
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{ *l=(?Pe<  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), C511hbF  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), UtP|<]{  
nStartPos,nEndPos,i); imeE&  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 0^sY>N"  
fileSplitterFetch.start(); G]4Ca5;Z!N  
} 1m#.f=u{R  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ixSr*+  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Gx6%Z$2n  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", >7zC-3  
nEndPos = " + nFileLength); ^ nI2<P  
// fileSplitterFetch[nPos.length-1].start(); Fx|`0LI+C  
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//等待子线程结束 N9-7YQ`D  
//int count = 0; XbB(<\0+  
//是否结束while循环 ;o9ixmT<-o  
boolean breakWhile = false; X6r0+D5AvB  
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@uldD"MJ<]  
while(!bStop) %^L{K[}  
{ S#?2E8  
write_nPos(); y<E];ub  
Utility.sleep(500); $`55
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breakWhile = true; f
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for(int i=0;i<nStartPos.length;i++) tP7<WGHd/  
{ #Uu,yHMv:;  
if(!fileSplitterFetch.bDownOver)
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{ X<$Tn60,  
breakWhile = false; {0Y6jk>I  
break; BZ1wE1t  
} YE~IO5   
} <D~hhGb  
if(breakWhile) Q(nTL WW  
break; 45sEhs[$  
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H3<tsK=:  
//count++; WSu6chz)  
//if(count>4) i[IFD]Xy!j  
// siteStop(); in<.0v9w  
} ,3Q~X$f  
 pE)NSZ  
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System.err.println("文件下载结束！"); Y~g{9 <!  
} V;xPZ2C;  
catch(Exception e){e.printStackTrace ();} FL^ _)`  
} eTvWkpK+  
j'z#V_S  
WJhTU@'  
//获得文件长度 *v+l,z4n  
public long getFileSize() QIGUi,R  
{ OR+qi*)  
int nFileLength = -1; 0]|`*f&p;  
try{ hi1Ial\Y  
URL url = new URL(siteInfoBean.getSSiteURL()); f47]gtB-  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); "kyCY9)
%  
httpConnection.setRequestProperty("User-Agent","NetFox"); f[k#Znr  
CW &z?Bra  
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int responseCode=httpConnection.getResponseCode(); I/Vw2  
if(responseCode>=400) 8~C_ng-wn  
{ 4=([v;fc  
processErrorCode(responseCode); }8ubGMr,Y  
return -2; //-2 represent access is error Ds">eNq  
} sE% $]Jp  
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String sHeader; 90<
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for(int i=1;;i++) a_>|N
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{ X/~uF9a'<  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); JI5o~;}m  
//Utility.log(in.readLine()); 4b2d(x)0X  
sHeader=httpConnection.getHeaderFieldKey(i); XDemdMy$  
if(sHeader!=null) %qoS(iO`h  
{ F^u12R)  
if(sHeader.equals("Content-Length")) t%lat./yT  
{ jzbq{#  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ,dIev<  
break; 7)lEZJK&T  
} tqGrhOt  
} @sXv5kZ
:  
else dkC[SG`  
break; SGAzeymw  
} ?_NKyiu95  
} yH/A9L,Z  
catch(IOException e){e.printStackTrace ();} :o'x?]  
catch(Exception e){e.printStackTrace ();} R=z])  
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Utility.log(nFileLength); CvoFt=c$jE  
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return nFileLength; FnO@\{M"A  
} }s~c(sL?;  
|6E_N5~  
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//保存下载信息（文件指针位置） C~ 1]  
private void write_nPos() :7v'[b  
{ IVR%H_uz  
try{ V@ >(xe7  
output = new DataOutputStream(new FileOutputStream(tmpFile)); C96/   
output.writeInt(nStartPos.length); --5F*a{R|  
for(int i=0;i<nStartPos.length;i++) G|wtl(}3  
{ n:5M E*  
// output.writeLong(nPos); \Vyys[MMY8  
output.writeLong(fileSplitterFetch.nStartPos); /LD3Bb)O  
output.writeLong(fileSplitterFetch.nEndPos); [9; @1I<x  
} XiW1X6  
output.close(); KdVKvs[  
} *1)>He$qL  
catch(IOException e){e.printStackTrace ();} n7Ao.b%uk-  
catch(Exception e){e.printStackTrace ();} ^tB1Nu%  
} [YDSS/  
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] ,|,/~  
//读取保存的下载信息（文件指针位置） Tgdy;?  
private void read_nPos() hOj{y2sc  
{ N^L@MR-  
try{ IG^@VQ%  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ]VI^
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int nCount = input.readInt(); WZ CI*'
 
nStartPos = new long[nCount]; ?.~1%l!  
nEndPos = new long[nCount]; ^6s im2  
for(int i=0;i<nStartPos.length;i++) g3^s_*A  
{
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nStartPos = input.readLong(); s(,S~  
nEndPos = input.readLong(); bZowc {!\  
} j\}.GM'8  
input.close(); h:Pfiw]  
} _){|/Zd  
catch(IOException e){e.printStackTrace ();} zIa={tU  
catch(Exception e){e.printStackTrace ();} z{XB_j6\=  
} e!u]l  
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private void processErrorCode(int nErrorCode)  5%-{r&  
{ "Q:Gd6?h;  
System.err.println("Error Code : " + nErrorCode); U,rI/'  
} j0l{Mc5  
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//停止文件下载 K^WDA]
)  
public void siteStop() teok*'b:  
{ v
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bStop = true; P(T-2Ux6  
for(int i=0;i<nStartPos.length;i++) 6wlLE5  
fileSplitterFetch.splitterStop(); `KQx#c>'  
`Vvi]>,cg`  
6,t6~Uo/  
} ^O}a,  
} cAR `{%b  
//负责部分文件的抓取 * + T(i  
**FileSplitterFetch.java XoN~d  
*/ lZk  z\  
package NetFox; %A z
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import java.io.*; )zL@h  
import java.net.*; '
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public class FileSplitterFetch extends Thread { ,dRaV</2  
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String sURL; //File URL =-sT
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long nStartPos; //File Snippet Start Position /WQ.,a  
long nEndPos; //File Snippet End Position 7xnj\9$m  
int nThreadID; //Thread's ID o\8?CNm1(  
boolean bDownOver = false; //Downing is over (Yewd/T  
boolean bStop = false; //Stop identical /A9RmTb  
FileAccessI fileAccessI = null; //File Access interface ^50dF:V(1  
qzW3MlD  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException R+LKa Z  
{ 'i+L  
this.sURL = sURL; ox-m)z `7  
this.nStartPos = nStart; b 3x|Dq.  
this.nEndPos = nEnd; NQ{(G8x9  
nThreadID = id; P%|~Ni_BTX  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 sK2N3B&6  
} #/>TuJc  
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public void run() bRvGetX  
{ D4VDWv  
while(nStartPos < nEndPos && !bStop) fJS:46  
{ ACyK#5E  
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try{ $a_y-lY  
URL url = new URL(sURL); "BQnP9  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); (p>|e\(]0  
httpConnection.setRequestProperty("User-Agent","NetFox"); E+]}KX:  
String sProperty = "bytes="+nStartPos+"-"; 3E*
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httpConnection.setRequestProperty("RANGE",sProperty); JL6$7h  
Utility.log(sProperty); </[.1&S+\  
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InputStream input = httpConnection.getInputStream(); zsp%Cz7T  
//logResponseHead(httpConnection); hTDK[4e  
#8Bh5L!SJ1  
h%/BZC^L]|  
byte[] b = new byte[1024]; J5{;+ysUMl  
int nRead; !Se0&O
b  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) p}^G#h{  
{ E0ED[d,  
nStartPos += fileAccessI.write(b,0,nRead); SA TX_  
//if(nThreadID == 1) `;85Mo:qJ  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); OHndZ$'fI  
} syw1Z*WK  
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Utility.log("Thread " + nThreadID + " is over!"); 3L&:  
bDownOver = true; :;_
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//nPos = fileAccessI.write (b,0,nRead); 9tHK_),9  
} ||:>&  
catch(Exception e){e.printStackTrace ();} @;egnXxF<  
} =+iY<~8  
} 5_(\Cd<#  
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%5e|  
//打印回应的头信息 bB$f=W!m%  
public void logResponseHead(HttpURLConnection con) {T8;-H0H  
{ :qE.(k1@5  
for(int i=1;;i++) y-hTTd"{  
{ HTL6;87w+]  
String header=con.getHeaderFieldKey(i); T?RY~GA  
if(header!=null) z"4 q%DC  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); VukbvBWPN  
Utility.log(header+" : "+con.getHeaderField(header)); 9VW/Af  
else \WiCI:  
break; X7$]qE K  
} T
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} /#00'(oD  
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public void splitterStop() DXf  
{ *J4!+GD  
bStop = true;  Gsh9D  
} DzR,ou  
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7L
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} 5M=U*BI  
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/* .'`aX 7{\  
**FileAccess.java X
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*//文件访问(定位，写) fnX[R2KZ  
package NetFox; k[8F: T-  
import java.io.*; sV#%U%un  

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public class FileAccessI implements Serializable{ $]LS!@ Rm  
N5K(yY_T  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ! \s}A7  
RandomAccessFile oSavedFile; Gbhw7 (&  
long nPos; 6 ZRc|ZQ  
(K[e=0Rf  
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public FileAccessI() throws IOException oOprzxf"+Z  
{ ;>2-  
this("",0); qcO~}MJr}^  
} 3chx4  
 B=*0  
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public FileAccessI(String sName,long nPos) throws IOException 2K_ QZ  
{ d_(>:|oh  
oSavedFile = new RandomAccessFile(sName,"rw"); k(G6` dY  
this.nPos = nPos; HIw)HYF2  
oSavedFile.seek(nPos); Vsi:O7|+ }  
} =p@2[Uo  
D,=~7/g  
&PXT$x[i  
public synchronized int write(byte[] b,int nStart,int nLen) oC" [rn  
{ wDi/oH/H  
int n = -1; 0fstEExw  
try{ >&HW6 c  
oSavedFile.write(b,nStart,nLen); PI L)(%
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n = nLen; T x Mh_  
} A)~oD_ooQ  
catch(IOException e) nZ=[6?  
{ LS*L XC  
e.printStackTrace (); [<i3l'V/[  
} KRGj6g+  
$

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return n; QN;5+p
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} |}^u<S8X  
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} i<m) s$u  
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/* e\(X:T  
**SiteInfoBean.java f\?Rhyz  
*/ /Q9
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package NetFox; R7b-/ !L  
"&XhMw4  
5G6 Pp7[  
public class SiteInfoBean { [ {"x{;  
|63uoRr  
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private String sSiteURL; //Site's URL yU(}1ZI
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private String sFilePath; //Saved File's Path i+QVs_jW  
private String sFileName; //Saved File's Name p".wqg*W  
private int nSplitter; //Count of Splited Downloading File c{`!$Z'k<  
MZ0cZv$v!~  
'/D2d  
public SiteInfoBean() 3,Z;J5VL4!  
{//nSplitter的缺省值为5 Tn,_0  
//default value of nSplitter is 5 l %zbx"%x  
this("","","",5); x| D|d}  
} 6;~V@t  
gs0
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) %q r,Ssa/  
{ F~fN7<9R  
sSiteURL= sURL; V@RdvQy  
sFilePath = sPath; 2T%sHp~qt  
sFileName = sName; 0 GFho$f  
this.nSplitter = nSpiltter; /Xc9}~t6  
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&RuTq6)r  
} ADxje%!1O  
cJ?,\@uuP  
?t}s3P!Q3w  
public String getSSiteURL() UZ<.R"aK  
{ {]|<|vc;GI  
return sSiteURL; hb0)<^xu  
} z<P?p  
uDcs2^2l  
bFG?mG:  
public void setSSiteURL(String value) 1QhQ#`$<1  
{ K)1Lg?j  
sSiteURL = value; vEG7A$Z"  
} g;q.vHvsc"  
37IHn6r\  
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public String getSFilePath() 2!9W:I7  
{ '9qyf<MlY  
return sFilePath; 5Uhxl^c  
} }U9dzU14  
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public void setSFilePath(String value)
b{<$OVc  
{ _h,X3P  
sFilePath = value; Az(,Q$"|5  
} AU}|o0Ur  
D;48VK/Q  
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public String getSFileName() 8"LM:0x  
{ [P6A$HC<  
return sFileName; V%t_,AT  
} S<*1b 6%D  
s/3sOb}sA  
VD!PF'  
public void setSFileName(String value) SEu:31k{o  
{ 1 K^-tms  
sFileName = value; [%/B"wTt  
} " :[;}f;  
GsD?Z%t~%  
F7=\*U  
public int getNSplitter() &P*r66  
{ XCgC^c'  
return nSplitter; uVX,[%*P  
} LF(S"Of  
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public void setNSplitter(int nCount) VVuNU"-  
{
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nSplitter = nCount; l;h -`( 11  
} u2':~h?l  
} C.}ho.} r  
DU5rB\!.~  
uc=u4@.>  
/* b+dmJ]c  
**Utility.java |\C.il7  
*/ >Fe=PRs  
package NetFox; ZY
6%%7?1  
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ep l1xfr  
public class Utility { ?f5||^7  
/sSif0I24  
(d[JMO^@8  
public Utility() B+'w'e$6  
{ OJ7
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I%0J=V;o{  
U71A#OD^U  
} X(>aW*q  
7+J<N@.d  
//线程睡眠 '\LU 8VC  
public static void sleep(int nSecond) Ns[.guWu-  
{  d|$-Sz  
try{ z%/<|` 7  
Thread.sleep(nSecond); koT: r  
} 1.z !u%2  
catch(Exception e) :J6FI6  
{ :N:e3$c  
e.printStackTrace (); ltmD=-]G_  
} ;UWp0d%  
} jD_B&MQz  
\'Ca
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//日志 VI^~I;M^  
public static void log(String sMsg) q&EwD(k  
{ ig:z[k?  
System.err.println(sMsg); _zFJ]7Ym.)  
} z_9qT"vF  
<p8>"~R  
]hA]o7k  
public static void log(int sMsg) C~VyM1inD  
{ L"V~MF  
System.err.println(sMsg); e\i}@]  
} D$bJs O  
} Hbz,3{o5  
ZUeA&&{  
h>jp.%oOu  
/* #h7$b@  
**TestMethod.java xT3l>9i  
*/ 7#iT
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package NetFox; ]7_O#MY1  
.2STBh.;  
:vy./83W  
public class TestMethod { WevXQ-eKm  
+jz%:D  
%c,CfhEV%&  
public TestMethod() 9IG3zMf  
{ ///xx/weblogic60b2_win.exe ZlsdO.G  
try{ Rk52K*Dc  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); cdsF<tpy  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); h2Jdcr#@FF  
SiteFileFetch fileFetch = new SiteFileFetch(bean); cK+y3`.0  
fileFetch.start(); &T/}
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} z[ N_3n  
catch(Exception e){e.printStackTrace ();} "t)|N dZm  
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} Qz?r4kR  
w*s#=]6
 
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public static void main(String[] args) 4 jeUYkJUM  
{ A?sU[b6_  
new TestMethod(); R7 *ek_  
} f~D> *<L4-  
} Qvd$fY**  
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