http断点续传简单实现（java)

/* IS }U2d,W  
**SiteFileFetch.java }719_DF  
*/ <h1J+  
package NetFox; &}lRij&`  
import java.io.*; N'0fB`:kz  
import java.net.*; 'J#uD|9)  
is=|rY9$  
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public class SiteFileFetch extends Thread { >4AwjS}H  
coc:$Sr%  
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SiteInfoBean siteInfoBean = null; //文件信息Bean  1O@cev;  
long[] nStartPos; //开始位置 hHqsI`7
c  
long[] nEndPos; //结束位置 uBBW2  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 \AB*C_Ri  
long nFileLength; //文件长度 iMs(Ywak]  
boolean bFirst = true; //是否第一次取文件 +P"u1q*+p  
boolean bStop = false; //停止标志 %'[ pucEF  
File tmpFile; //文件下载的临时信息 %Z#[{yuFs  
DataOutputStream output; //输出到文件的输出流 D$bJs O  
<e'l"3+9(  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） SrSm%Dv  
public SiteFileFetch(SiteInfoBean bean) throws IOException yg@}j   
{ %Wb$qpa  
siteInfoBean = bean; kv?j]<WN  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); x\6i(k-  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); #h7$b@  
if(tmpFile.exists ()) AV["%$:  
{ 7:h_U9Za?$  
bFirst = false; kZvh<NFh_  
read_nPos(); J~rjI24  
} \b|Q`)TK  
else \G &q[8F\  
{ 9 kS;_(DB  
nStartPos = new long[bean.getNSplitter()]; 38(|a5  
nEndPos = new long[bean.getNSplitter()]; JWs?az  
} W|[k]A` 2  
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} N`i`[ f  
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public void run() &5;y&dh  
{ FuZLE%gP  
//获得文件长度 ( 0Z3Ksfj1  
//分割文件 l j*J|%~  
//实例FileSplitterFetch O(f&0h
!  
//启动FileSplitterFetch线程 }=^Al;W  
//等待子线程返回 4\EvJg@Z.  
try{ 'QEQyJ0EB  
if(bFirst) 7_ah1IEK  
{ KdTna6nY  
nFileLength = getFileSize(); xDBHnr}[  
if(nFileLength == -1) z6Jfu:_N!  
{ H!ISQ8{V  
System.err.println("File Length is not known!"); i3\6*$Ug  
} wPU<jAQyp  
else if(nFileLength == -2) 7u7 <"?v=  
{ >c:- ;(k  
System.err.println("File is not access!"); H(Q|qckj  
} *;C8g{  
else zE<GwVI~  
{ db.E-@W.OI  
for(int i=0;i<nStartPos.length;i++) N?;5%pG <  
{ B[Fuyy?  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); rSfvHO:R  
} 1f`=U0  
for(int i=0;i<nEndPos.length-1;i++) )Y+?)=~  
{ A4uDuB;;ZQ  
nEndPos = nStartPos[i+1]; ,\
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} k@= LR  
nEndPos[nEndPos.length-1] = nFileLength; `mTc  
} r=ds'n"  
} 7Y(ySW  
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A?sU[b6_  
//启动子线程 PNMf5'@m  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; n/]$k4h  
for(int i=0;i<nStartPos.length;i++) Yl6\}_h`  
{ O6pL )6d  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), xiPP&$mg  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), B>&eciY  
nStartPos,nEndPos,i); sZhl.[&zo  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); QWBQ0#L  
fileSplitterFetch.start(); \aO.LwYm;:  
} ]xIfgSq  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), S*1Km&  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); NCM&6<_  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", MO$dim>  
nEndPos = " + nFileLength); r?=7#/]  
// fileSplitterFetch[nPos.length-1].start(); 1y5$  
h}_1cev?  
/M "E5  
//等待子线程结束 |<ZkJR3B  
//int count = 0; !*gTC1bvB  
//是否结束while循环 e r;3TG~  
boolean breakWhile = false; 88ydAx#P  
^L<*ggw  
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while(!bStop) S qQqG3F  
{ sm>Hkci%
 
write_nPos(); k(;c<Z{?1  
Utility.sleep(500); ^f,('0p->  
breakWhile = true; P2Ja*!K]  
'.wyfSH@  
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for(int i=0;i<nStartPos.length;i++) g{cHh(S  
{ SAEr$F^  
if(!fileSplitterFetch.bDownOver) &n:F])`2  
{ yv<0fQ  
breakWhile = false;  o2ndnIL  
break;  -'|pt,)  
} Vhww-A  
} 5)yQrS !{:  
if(breakWhile) sQS2U6  
break; ~4mgYzOmD`  
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//count++; 7n~BDqT  
//if(count>4) j}
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// siteStop(); 
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} D>O{>;y[   
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System.err.println("文件下载结束！"); U!-|.N,  
} X~Li`  
catch(Exception e){e.printStackTrace ();} 1lNg} !)[K  
} T@]vjXd![  
(r^IW{IndX  

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//获得文件长度 t _Q/v
 
public long getFileSize() x=qACoq  
{ rY>{L6d  
int nFileLength = -1; 1
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try{ ` m`Sl[
6  
URL url = new URL(siteInfoBean.getSSiteURL()); Iy](?b  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 5}R/C{fs  
httpConnection.setRequestProperty("User-Agent","NetFox"); &:-`3J-  
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int responseCode=httpConnection.getResponseCode(); x c-=;|s  
if(responseCode>=400) 56o?=|  
{ m)q;eQs  
processErrorCode(responseCode); 0n_Cuh\  
return -2; //-2 represent access is error (o\:rLZu  
} 'lv\I9"S)  
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String sHeader; Y:VM5r)  
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for(int i=1;;i++) &,fBg6A%  
{ Z$,1Tk"O/s  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); vbQo8GFp}  
//Utility.log(in.readLine()); (0"9562  
sHeader=httpConnection.getHeaderFieldKey(i); oS$&jd  
if(sHeader!=null) oj<.axA,  
{ ]P ->xJ  
if(sHeader.equals("Content-Length")) m\4jiR_o  
{ <9/oqp{C4  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 7fl'nCo\"  
break; 6kjBd3  
} |J`YFv  
} u:N/aaU=  
else }_M.-Xm  
break; A{;b^IK  
} 3u7E?*{sH  
} r}QW!^F  
catch(IOException e){e.printStackTrace ();} ;=6++Oq  
catch(Exception e){e.printStackTrace ();} 8@/]ki`>  
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Utility.log(nFileLength); `2NL'O:  
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return nFileLength; x
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} [(`T*c.#.X  
d?&?$qf[  
q!<`ci,uS  
//保存下载信息（文件指针位置） ^?toTU   
private void write_nPos() _q=$L eO5  
{ /Yx 1S'5  
try{ mxQS9y
 
output = new DataOutputStream(new FileOutputStream(tmpFile)); s+^o[R T3  
output.writeInt(nStartPos.length); eF}Q8]da  
for(int i=0;i<nStartPos.length;i++) X<(h)&E  
{ 5<a)SP 0  
// output.writeLong(nPos); J C1T033 r  
output.writeLong(fileSplitterFetch.nStartPos); o&?Tz*"l  
output.writeLong(fileSplitterFetch.nEndPos); d+ih]?  
} #0L:h?L  
output.close(); !HqIi@>8  
} q`}Q[Li  
catch(IOException e){e.printStackTrace ();} f<WnPoV  
catch(Exception e){e.printStackTrace ();} OV>T}Fq  
} rP;Fh|w#  
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Y.i<7pBt  
//读取保存的下载信息（文件指针位置） KE16BjX@  
private void read_nPos() ; ZL<7tLDb  
{ dlK#V)  
try{ %o#D"  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); $}OU~d1q  
int nCount = input.readInt(); 0c7&J?"wE  
nStartPos = new long[nCount]; f;pR8  
nEndPos = new long[nCount]; UY{ Uo@k9x  
for(int i=0;i<nStartPos.length;i++) $1\<>sJH  
{ \p@,+ -gX  
nStartPos = input.readLong(); ahS*YeS7  
nEndPos = input.readLong(); L|6clGp  
} JeUFCWm  
input.close(); [4Glt>Nj>  
} F^
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catch(IOException e){e.printStackTrace ();} J`}/+WN7  
catch(Exception e){e.printStackTrace ();} G+b$WQn2t  
} @'R4zJ&+S  
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private void processErrorCode(int nErrorCode) <5[wP)K@  
{ =[t([DG  
System.err.println("Error Code : " + nErrorCode); )Ah  
} ui G7  
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yKOf]m>#  
//停止文件下载 5&2=;?EO  
public void siteStop() `W?aq]4x5  
{ '/;#{("  
bStop = true; *-_` xe  
for(int i=0;i<nStartPos.length;i++) wXXv0OzK  
fileSplitterFetch.splitterStop(); Xj+1]KRN  
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} +Z$X5Th  
} !j%)nU  
//负责部分文件的抓取 kc|`VB8L  
**FileSplitterFetch.java n?Gm 5##  
*/ x gaN0!  
package NetFox; mkj`z  
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import java.io.*; U@m<  
import java.net.*; 3$l'>v+5{  
/ )5B  
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public class FileSplitterFetch extends Thread { Gk799SDL  
t ~U&a9&Z  
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String sURL; //File URL "Oh-`C  
long nStartPos; //File Snippet Start Position $
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long nEndPos; //File Snippet End Position wOHK dQ'  
int nThreadID; //Thread's ID wc~a}0uz  
boolean bDownOver = false; //Downing is over Gu*;z% b2  
boolean bStop = false; //Stop identical faD(,H  
FileAccessI fileAccessI = null; //File Access interface nsw.\(#  
s;8J= \9W  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException )dC%g=dtc  
{ G0> 'H1Z  
this.sURL = sURL; b4ORDU  
this.nStartPos = nStart; go2:D#mf  
this.nEndPos = nEnd; 0 "pm7  
nThreadID = id; 6=A++H@  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 rx_'(  
} N[aK#o,  
{U^mL6=&v  
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public void run() 1#]tCi`  
{ 7i334iQZ  
while(nStartPos < nEndPos && !bStop) te" 8ZmJ  
{ a4g=cs<9}  
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try{ `j4ukOnG  
URL url = new URL(sURL); C&<f YCwG  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); i1 SP  
httpConnection.setRequestProperty("User-Agent","NetFox"); ?$-OdABXHK  
String sProperty = "bytes="+nStartPos+"-"; u4z]6?,"e  
httpConnection.setRequestProperty("RANGE",sProperty); uZmfvMr3  
Utility.log(sProperty); lP9a*>=a  
:Nc~rOC_  
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InputStream input = httpConnection.getInputStream(); 1/a*8vuGh  
//logResponseHead(httpConnection); 1v`<Vb%"}T  
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byte[] b = new byte[1024]; JguE#ob2  
int nRead; gA~Ih  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) oPzt1Y  
{ BR5$;-7W  
nStartPos += fileAccessI.write(b,0,nRead); wg!  
//if(nThreadID == 1) ;EL!TzL:8  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); kz,Nz09}W  
} Sm+Ek@Ax  
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 9l{r&]  
Utility.log("Thread " + nThreadID + " is over!"); Am kHVg  
bDownOver = true; C/!2q$  
//nPos = fileAccessI.write (b,0,nRead); ]>R`]U9*O  
} xiA9X]FB  
catch(Exception e){e.printStackTrace ();} _6=6 b!hD  
} .%WbXs  
} x0Tb7y`  
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bG.aV#$FIg  
//打印回应的头信息 N1#*~/sXh  
public void logResponseHead(HttpURLConnection con) <-}6X  
{ wQM(Lm#Q  
for(int i=1;;i++) C+y:<oo)  
{ y3;G<9K2c]  
String header=con.getHeaderFieldKey(i); ix7N q7!N  
if(header!=null) &)xoR4!2  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); +` Em&  
Utility.log(header+" : "+con.getHeaderField(header)); ub,Sj{Mq"  
else wG^{Jf&@$  
break; 5"XcVH4g  
} V)N9V|O'  
} IWm|6@y  
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;  
public void splitterStop() InPq1AH  
{ ;"joebZ/  
bStop = true; uo 7AU3\  
} *<Qn)Az  
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} m{R`1cN=Hg  
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/* m:p1O3[R  
**FileAccess.java Qs;bVlp!H  
*//文件访问(定位，写) !Otyu6&  
package NetFox; #[I`VA\x  
import java.io.*; n/^wzG  
#@y4/JS&2  
^
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public class FileAccessI implements Serializable{ p(U'c}@2
 
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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 )W*S6}A  
RandomAccessFile oSavedFile; 8#7z5:_  
long nPos; !\?? [1_e  
G'{4ec0<{  
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public FileAccessI() throws IOException /A<L  
{ 2,NQ(c_c$  
this("",0); 6PvV X*5T  
} c(YNv4*X  
,VJ0J!@  
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public FileAccessI(String sName,long nPos) throws IOException o1I{^7/  
{ 1{nXmtvr  
oSavedFile = new RandomAccessFile(sName,"rw"); #W!@j"8eK  
this.nPos = nPos; ~poy`h'  
oSavedFile.seek(nPos); g%RL9-z  
} a8Ci 7<V  
oqUtW3y  
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public synchronized int write(byte[] b,int nStart,int nLen) nuKjp Ap!  
{ w(.k6:e  
int n = -1; #Q$9Eq8"[  
try{ fTV:QAa;  
oSavedFile.write(b,nStart,nLen); hua{g_  
n = nLen; R:i7Rb2C  
} C4Bh#C  
catch(IOException e) \t^q@}~0Wz  
{ 0Ba-VY.H  
e.printStackTrace (); t[iE >  
} 0P%(4t$pd  
9<\wa/#  
>KM<P[BRd  
return n; In^$+l%O[  
} N55;oj_K  
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} Ojie.+'SB  
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K.b-8NIUW  
/* ddlLS  
**SiteInfoBean.java eNN%%Q  
*/ ,Iwri\  
package NetFox; Tv~<W4  
A[=)Zw "  
S37Bl5W  
public class SiteInfoBean { 5XA6IL|/l  
)}n`MRDB  
J%3S3C2*m  
private String sSiteURL; //Site's URL tC-(GDGy5  
private String sFilePath; //Saved File's Path _YO`x  
private String sFileName; //Saved File's Name @ZD1HA,h"  
private int nSplitter; //Count of Splited Downloading File *vUKh^="  
0(:"q!h  
/>K$_T/]  
public SiteInfoBean() :
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{//nSplitter的缺省值为5 xJN Jv
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//default value of nSplitter is 5 ]W-:-.prh  
this("","","",5); Zpl?zI  
} N;<<-`i  
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[  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) rK}*Uwut  
{ q.uI
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sSiteURL= sURL;
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sFilePath = sPath; \W}?4kz  
sFileName = sName; L;E9"7
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this.nSplitter = nSpiltter; ,MuLu,$/  
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}
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d!e$BiC  
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public String getSSiteURL() KzI$GU3  
{ )bw^!w)  
return sSiteURL; q ( H^H  
} 9'td}S  
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Y -
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public void setSSiteURL(String value) m:II<tv  
{ "2N3L8?k  
sSiteURL = value; VO#]IXaP  
} K=+w,H#`C  
^\{%(i9  
/|`;|0/2
 
public String getSFilePath() !|!:MYn  
{ }oj$w?Ex  
return sFilePath; Wi hQj  
} +%$!sp?  
9V[|_  
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public void setSFilePath(String value) uTBls8  
{ rsOon2|  
sFilePath = value; i2)rDek3]T  
} c*HS#C7'2  
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public String getSFileName() }!lLA4XRr  
{ [$OD+@~A2  
return sFileName; 2,E&}a|;b  
} nPR_:_^  
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QYyF6ht=!  
public void setSFileName(String value) DZRkK3  
{ HiILJyb  
sFileName = value; =36vsps=  
} | z$ba:u5  
9%>H}7=  
eIg ' !8h?  
public int getNSplitter() )=[K$>0k  
{ %* vYX0W"  
return nSplitter; c^Rz?2x  
} 3yZtyXRPn  
(ZT*EFhb(  
1sGkbfh{t  
public void setNSplitter(int nCount) s80:.B  
{ z,I7 PY& G  
nSplitter = nCount; "Yq-s$
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} fw|r{#d  
} XDz![s  
{jJUS>  
o8H<{D13  
/* < 5;0LPU  
**Utility.java UN_lK<utF  
*/ FavU"QU&|  
package NetFox; .G?7t6A  
fn&gM\<-+(  
m/cbRuPWgP  
public class Utility { UI_|VU>J  
K>,Kbs=D6  
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public Utility() wvp
\'* $  
{ hc`9Y  
!|}J{  
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} lWd)(9Kj  
V[rNJf1z  
//线程睡眠 DTl
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public static void sleep(int nSecond) Rr|VGtg  
{ =LZj6'  
try{ MDGcK/$')f  
Thread.sleep(nSecond); --Dw8FR9  
} A WMR0I  
catch(Exception e) }sd-X`lZ  
{ N 2L/A
 
e.printStackTrace (); HI,1~Jw+  
} va95/(  
} Yw\}'7  
pvDr&n9  
//日志 NA]7qb%%<  
public static void log(String sMsg) [qIi_(%o  
{ wU2y<?$\8  
System.err.println(sMsg); RR75ke[Hs  
} pIC CjA?3@  
ryW1OV6?_0  
V%<<Udu<  
public static void log(int sMsg) }rn}r4_a  
{ Kbg`
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System.err.println(sMsg); q4xB`G  
} f8lBxK  
} HP3~.1Sp  
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?0DCjh8We  
/* TEh]-x`  
**TestMethod.java 0{BPT>'  
*/ 23
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package NetFox; U#Wc!QN-t  
uQ vW@Tt  
x +q"%9.c  
public class TestMethod { ~V`D@-VND  
8v*>~E/0  
>#$(M5&}-  
public TestMethod() fh b&_T  
{ ///xx/weblogic60b2_win.exe p<Ah50!B  
try{ p27A#Uu2}  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); i74^J+xk  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); C$"jZcm,I  
SiteFileFetch fileFetch = new SiteFileFetch(bean); v|?hc'
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fileFetch.start(); nxsQDw\hy  
} mB"zyL-  
catch(Exception e){e.printStackTrace ();} 2^ ^;Q:  
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k]qZOO}  
} ,au64sH  
5caYA&R  
N>/*)Frt  
public static void main(String[] args) p87s99  
{ T 2x~fiM  
new TestMethod(); eG"iJ%I  
} %,K|v  
} V~Tjz%<  
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