http断点续传简单实现（java)

/* 8PQ$X2)  
**SiteFileFetch.java ly^F?.e-  
*/ IE,g  
package NetFox; `qfVgT=2  
import java.io.*; 'z!I#Y!Y  
import java.net.*; xQmk2S` y  
Y %<B,3  
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public class SiteFileFetch extends Thread { .Qi`5C:U  
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4!monaB"e  
SiteInfoBean siteInfoBean = null; //文件信息Bean wS:323 !l$  
long[] nStartPos; //开始位置 YemOP9  
long[] nEndPos; //结束位置 rc;| ,\  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 0<^K0>lm p  
long nFileLength; //文件长度 !\"C
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boolean bFirst = true; //是否第一次取文件 %K%8 ~B  
boolean bStop = false; //停止标志 D|+H!f{k  
File tmpFile; //文件下载的临时信息 6.By)L  
DataOutputStream output; //输出到文件的输出流 }Y-f+qX*  
2&=;$2?}  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ^
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public SiteFileFetch(SiteInfoBean bean) throws IOException PHz/^p3F  
{ #G]s.by('  
siteInfoBean = bean; }}Q|O]e  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); TuX#;!p6  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 2 3>lE}^G  
if(tmpFile.exists ()) pR~PB  
{ v#nFPB=z  
bFirst = false; %GHHnf%2Z  
read_nPos(); v3hNvcMpf  
} GLk7#Y  
else %r|fuwwJO  
{ .oSKSld  
nStartPos = new long[bean.getNSplitter()]; P~]BB.tog  
nEndPos = new long[bean.getNSplitter()]; t#<q O6&B  
} ^ ]`<nO  
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} d B?I(  
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public void run() nYE_WXY3V  
{ ^]Gt<_  
//获得文件长度 X|8Yz3:o  
//分割文件 ~ae68&L6  
//实例FileSplitterFetch qAG0t{K  
//启动FileSplitterFetch线程 Z\@vN[[  
//等待子线程返回 -;Hd_ ~O>j  
try{ SYl:X  
if(bFirst) }3vB_0[r  
{
2-{8+*_'  
nFileLength = getFileSize(); \8<bb<`  
if(nFileLength == -1) ]YwIuz6]  
{ 4jar5Mz  
System.err.println("File Length is not known!"); a
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} _ sM$O>  
else if(nFileLength == -2) fC(lY4,H3R  
{ d5bj$oH  
System.err.println("File is not access!"); @$tQz  
} Z1q'4h=F.  
else m6g+ B>  
{ g#Yqw  
for(int i=0;i<nStartPos.length;i++) Hm4lR{A  
{ 6 rmK_Y  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); mp@JsCU  
} o F@{&  
for(int i=0;i<nEndPos.length-1;i++) X'iki4  
{ W+1V&a}E  
nEndPos = nStartPos[i+1]; J }JT%SW  
} e6{/e+/R  
nEndPos[nEndPos.length-1] = nFileLength; MR8-xO'w  
} "
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} qr6WSBc  
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V1j&>-]]9*  
//启动子线程 AKL~F|t  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; zwAuF%U  
for(int i=0;i<nStartPos.length;i++) @*_#zU#g  
{ "hQV\|!\  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ]=h Ts%]w  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), O|av(F9  
nStartPos,nEndPos,i); Wx:_F;  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); <2,@rYe/  
fileSplitterFetch.start(); |a'Q^aT  
} 36lIV,YnU  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), [i&
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); (U-p&q>z  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", RV&2y=eb  
nEndPos = " + nFileLength); z.[L1AGa|s  
// fileSplitterFetch[nPos.length-1].start(); Jbs:}]2  
_+^3<MT  
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//等待子线程结束 5X~ko>  
//int count = 0; r$0=b -  
//是否结束while循环 FeCQGT  
boolean breakWhile = false; xaSkn  
-3KB:K<  
6"%[s@C  
while(!bStop) R[#5E|` `9  
{ oNiS"\t  
write_nPos(); hvpn=0@M  
Utility.sleep(500); KAUYE^  
breakWhile = true; 85s{;3  
A"9aEOX-?i  
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for(int i=0;i<nStartPos.length;i++) Y!Z@1V`  
{ J-X5n 3I&  
if(!fileSplitterFetch.bDownOver) vTB*J,6.  
{ sCnZ\C@u  
breakWhile = false; hO(HwG?8t  
break; sIELkF?.  
} ^,`Lt *  
} 6+LXoR'  
if(breakWhile) XK&#K? M  
break; p
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 sRoZvp5  
//count++; }]?RngTt  
//if(count>4) @MN>ye'T  
// siteStop(); +{#BQbx6  
} W]y$6P  
[s7I.rdGzz  
|-e=P9,  
System.err.println("文件下载结束！"); />n0&~k[h  
} se)I
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catch(Exception e){e.printStackTrace ();} tB1Qr**  
} oxad}Y  
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neZ_TT/
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//获得文件长度 fnXl60C%  
public long getFileSize() m\~[^H~g  
{ bUqO.FZ[  
int nFileLength = -1; E8-p ,e,  
try{ E+3~w?1  
URL url = new URL(siteInfoBean.getSSiteURL()); ^Xb!dnT.*a  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); B1p9pr  
httpConnection.setRequestProperty("User-Agent","NetFox"); j+Tk|GRab  
5 wc&0h  
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int responseCode=httpConnection.getResponseCode(); 9ge$)q
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if(responseCode>=400) 2.:b  
{ w]%r]PwU+  
processErrorCode(responseCode); j#~4JGZt  
return -2; //-2 represent access is error ")o.x7
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} OPjscc5  
|]B]0J#_  
zd;xbH//)b  
String sHeader; oYqC"g&4Z  
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for(int i=1;;i++) .^v7LF]Q  
{ %EVg.k$  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ~ 01]VA  
//Utility.log(in.readLine()); :
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sHeader=httpConnection.getHeaderFieldKey(i); 6!gGWn5>}  
if(sHeader!=null) dkVVvK  
{ +~[19'GH  
if(sHeader.equals("Content-Length")) , D&FCs%v  
{ W>,b1_k c  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); @lBH@HR=C  
break; I]$kVa1iN  
} {`}RYfZ
 
} CP?\'a"Kt  
else >MhkNy  
break; &MKv_  
} =Of#Ps
)  
} 0u0Hl%nl  
catch(IOException e){e.printStackTrace ();} |Rab'9U^  
catch(Exception e){e.printStackTrace ();} "w7:{E5e  
"%Rx;xw|  

i\PN  
Utility.log(nFileLength); EM([N*8o  
#}vcffgZ  
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return nFileLength; *.K}`89T  
} 8m6L\Z&  
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VWNmqeP  
//保存下载信息（文件指针位置） }ShZ4 xMz  
private void write_nPos() yC _X@o-n  
{ 7aU*7!U  
try{ 9:esj{X  
output = new DataOutputStream(new FileOutputStream(tmpFile)); FB</~ g  
output.writeInt(nStartPos.length); -MU^%t;-  
for(int i=0;i<nStartPos.length;i++) |E}N8\Gr  
{ +XIN
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// output.writeLong(nPos); t[DXG2&  
output.writeLong(fileSplitterFetch.nStartPos); Yt{Y)=_t  
output.writeLong(fileSplitterFetch.nEndPos); 1 8&^k|  
} T0Gu(c`1d  
output.close(); @ 8SYV}0H  
} [NuayO
3  
catch(IOException e){e.printStackTrace ();} AFY;;_Xks  
catch(Exception e){e.printStackTrace ();} (yZ^Y'0  
} N8!B2uPQ  
Lu<'A4Q1  
#q=?Zu^Da  
//读取保存的下载信息（文件指针位置） x JepDCUJ>  
private void read_nPos() ^h' wZ7-\  
{ A\?O5#m:$  
try{ }5%!:=  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); )v'DQAL  
int nCount = input.readInt(); fdPg{3x*k  
nStartPos = new long[nCount]; [g%oo3`A  
nEndPos = new long[nCount]; kgA')]  
for(int i=0;i<nStartPos.length;i++) |D<~a(0  
{ .m4K ]^m  
nStartPos = input.readLong(); 0Uybh.dC  
nEndPos = input.readLong(); udw5A*Ls  
} PvO>}(=  
input.close(); j:fL_1m  
} bhFzu[B  
catch(IOException e){e.printStackTrace ();} Z*leEwgz  
catch(Exception e){e.printStackTrace ();} gB&'MA!  
} > ^D10Nf*  
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private void processErrorCode(int nErrorCode) G<>`O;i  
{ o^lKM?t  
System.err.println("Error Code : " + nErrorCode); /#.6IV(  
} F9Mv$g79  
xeZ,}YP)  
)<!y_;$A  
//停止文件下载 Xd{"+'29  
public void siteStop() 5B"j\TwQ  
{ {E>kFeg  
bStop = true; |2^cPnv?G&  
for(int i=0;i<nStartPos.length;i++) 9.>v ;:vL  
fileSplitterFetch.splitterStop(); #Z8<H  
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8/]5h%  
} D4[t@*m>7  
} E{1O<qO<  
//负责部分文件的抓取 }Vk#w%EJ  
**FileSplitterFetch.java `@-H ;  
*/ qm8[ ^jO&  
package NetFox; #M%-q8  
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s [@II]  
import java.io.*; D1#fy=u69|  
import java.net.*; "1WwSh}Z  
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public class FileSplitterFetch extends Thread { 1iig0l6\m  
5Z1b9.;.,  
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String sURL; //File URL \"|E8A6/  
long nStartPos; //File Snippet Start Position SW# 5px`  
long nEndPos; //File Snippet End Position o[&*vc)  
int nThreadID; //Thread's ID @tR:}J*9s  
boolean bDownOver = false; //Downing is over FK{Vnj0  
boolean bStop = false; //Stop identical 5Ta<$t  
FileAccessI fileAccessI = null; //File Access interface Y{6y.F*Q#  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException tp7cc;0  
{ fH}#.vy  
this.sURL = sURL; r[ni{&  
this.nStartPos = nStart; criOJ-  
this.nEndPos = nEnd; 4'Potv@/  
nThreadID = id; .}=gr+<bf  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 F4`ud;1H  
} lhZXq!2p  
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public void run() =c8xg/  
{ Psm5J80}n  
while(nStartPos < nEndPos && !bStop) >cpT_M&C,  
{ vz[oy|{F  
+" |?P  
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try{ R6eKI,y\"  
URL url = new URL(sURL); <$metN~9j  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); |KY6IGcqV  
httpConnection.setRequestProperty("User-Agent","NetFox"); o"wvP~H  
String sProperty = "bytes="+nStartPos+"-"; !8~A
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httpConnection.setRequestProperty("RANGE",sProperty); EX@wenR  
Utility.log(sProperty); UNY O P{  
5 6w6=Is  
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InputStream input = httpConnection.getInputStream(); {8p<iY- %  
//logResponseHead(httpConnection);
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byte[] b = new byte[1024]; Lp31Y .4  
int nRead; O2N7qV3U,  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) inQ1$  
{ 5y^I~"_i  
nStartPos += fileAccessI.write(b,0,nRead); &"lSq2  
//if(nThreadID == 1) 9 n0?0mk  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); V) xwlvX  
} Y(mnGaVn  
%/;*Ewwb  
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Utility.log("Thread " + nThreadID + " is over!"); -<0xS.^  
bDownOver = true; -qyhg-k6  
//nPos = fileAccessI.write (b,0,nRead); Z; 6N7U  
} U\y:\+e l  
catch(Exception e){e.printStackTrace ();} s$g3_
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} nz2`YyR  
} CWdpF>En  
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//打印回应的头信息 .D3k(zZ  
public void logResponseHead(HttpURLConnection con) \JLea$TM:  
{ h~`^H9?M  
for(int i=1;;i++) mE"(d*fe'  
{ )Szn,  
String header=con.getHeaderFieldKey(i); 4$oDq  
if(header!=null) n:"0mWnL$y  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); joA>-k04  
Utility.log(header+" : "+con.getHeaderField(header)); 7TW&=(  
else (&i c3/-  
break; */'j[uj  
} Yr)<1.K4,M  
} 2`^M OGYk  
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public void splitterStop() O$ARk+  
{ #g#[|c.  
bStop = true; i~"lcgoO  
} y9Pw'4R  
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} K-b`KcX  
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9 lXnNK |]  
/* ;$vVYC  
**FileAccess.java f"-3'k
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*//文件访问(定位，写) 3Yf~5csY  
package NetFox; &3Ry0?RET  
import java.io.*; V'FKgzd  
O/.8;.d;4Y  
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public class FileAccessI implements Serializable{ LfvNO/:,  
q*<FfO=eQ  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 e7yn"kd  
RandomAccessFile oSavedFile; :z`L)  
long nPos; rRXF@  
P N(<=v&E  
FI@kE19  
public FileAccessI() throws IOException W[LQ$uj  
{ ^7Ebg5<  
this("",0); ~zoZ{YqP  
} _xM}*_<VP  
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public FileAccessI(String sName,long nPos) throws IOException )0\D1IFJ  
{ v2ab84 C*  
oSavedFile = new RandomAccessFile(sName,"rw"); ;y
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this.nPos = nPos; 1QbD]"=n  
oSavedFile.seek(nPos); ?NxaJ^  
} O{Z bpa^  
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Cy5M0{  
public synchronized int write(byte[] b,int nStart,int nLen) ~3$:C#"Dl  
{ f9HoQDFsM  
int n = -1; $VeQvm*  
try{  n[7=  
oSavedFile.write(b,nStart,nLen); t; @T~%  
n = nLen; BO>[\!=y  
} .X"\ Mg  
catch(IOException e) ;It1i`!R  
{
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e.printStackTrace (); op,mP0b  
} X CHN'
l'  
+ 7nA; C  
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return n; ,[
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} AQs_(L
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} X1="1{8H  
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/* ~Dj_N$_+9  
**SiteInfoBean.java CMfR&G,)  
*/ {W
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package NetFox; > M4QEv  
TYedem<$  
(Zu8WyT2  
public class SiteInfoBean { %)L|7v<  
b@[\+P] "  
A"B[F#
  
private String sSiteURL; //Site's URL -l$-\(,M`#  
private String sFilePath; //Saved File's Path ETaLE[T%1  
private String sFileName; //Saved File's Name }#E~XlX^  
private int nSplitter; //Count of Splited Downloading File Es+BV+x[.c  
/pz(s+4=  
p"q4R2_/jh  
public SiteInfoBean() !{4bC  
{//nSplitter的缺省值为5 I< Rai"  
//default value of nSplitter is 5 FhMl+Ou  
this("","","",5); -;U3$[T,J7  
} -42jeJS  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) #VM-\02o  
{ k&3'[&$I*,  
sSiteURL= sURL; A@OSh6/{h  
sFilePath = sPath; g}
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sFileName = sName; &;oWmmvz{  
this.nSplitter = nSpiltter; 8(0q,7)y  
fAV=O%^  
f*ZIBTb 9  
} O$ ;:5zT  
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j?P8&Fm<  
public String getSSiteURL() 0x8aKq\'  
{ 3}X;WE `  
return sSiteURL; )6Qk|gIu(  
} OcGHMGdn  
4)~GHb  
N;d@)h(N!  
public void setSSiteURL(String value) N}j^55M_]  
{ 6GtXM3qtS  
sSiteURL = value; qddP-uN  
} [vY? !  
rWMG_eP:  
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public String getSFilePath() C/x<_VJzN/  
{ l/w<R  
return sFilePath; :$>TeCm  
} @AU<'?k  
P(&9S`I  
B?)=d,E  
public void setSFilePath(String value) GS4 HYF  
{ RAW(lZ(  
sFilePath = value; 0 SeDBs  
} z`[q$H7?  
t
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Y l1sAf/  
public String getSFileName() 'Nbae-pf  
{ #7~M1/eH=t  
return sFileName; KW.QVBuVO#  
} \#; -C<[b  
;/8oP ;X2  
Z;#Ei.7p|  
public void setSFileName(String value) +\a`:QET  
{ ymLhSF][  
sFileName = value; RjS&^uaP  
} 5B'};AQ  
N{<=s]I%x  
JS<4%@  
public int getNSplitter() w3=Bj  
{ RrDNEwAr  
return nSplitter; j&.MT@  
} HV??B :  
\e/'d~F  
8U07]=Bt<  
public void setNSplitter(int nCount) {{?[b^  
{ e'c~;Z\A
 
nSplitter = nCount; / ` 7p'i  
} q.OkZI0n  
} rI5)w_E?  
.`OdnLGy  
1YA_`_@w  
/* Ny>tJ~I  
**Utility.java 5CxD ys&<  
*/ k@eU #c5c  
package NetFox; u$N2uFc  
Z%Nl<i  
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public class Utility { 8}0W_CU,  
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public Utility() JBCcR,\kM*  
{ kne{Tp  
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k=<,A'y-/  
} ;(Q4x"?I  
qJj;3{X2  
//线程睡眠 H[guJ)4#@  
public static void sleep(int nSecond) ;/W;M> ^  
{ Y?2I /  
try{ U3 e3  
Thread.sleep(nSecond); c,1Yxg]|  
} xn&G`  
catch(Exception e) 1pC!F ;9Oo  
{  =uZ[  
e.printStackTrace (); adh=Kp e!w  
} gRuNC=sR  
} I)AV  
pq6}q($Rk  
//日志 bE2^sx`(  
public static void log(String sMsg) DD\:glo  
{ 0A@'w*=  
System.err.println(sMsg); mu2r#I  
} EZz Ox(g  
udDh
J?  
=yiR
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public static void log(int sMsg) zR/d:P
?  
{ "w0>  
System.err.println(sMsg); (b Q1,y  
} P=eVp(/x  
}  *ta ``q  
"P=OpFV  
ja}_u}:  
/* eOjoxnD-$  
**TestMethod.java imAsE;:  
*/ 
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package NetFox; >v@R]9  
_niXl&C  
]S4kWq{Y  
public class TestMethod { V2cLwQ'0  
v`MCV29!}  
}s=D,_}m  
public TestMethod() 7wsn8_n9  
{ ///xx/weblogic60b2_win.exe '<~l%q  
try{ dJM)~Ay-  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 4mJ4)  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); " 4#V$V  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Ln0rm9FV-  
fileFetch.start(); V&<vRIsN  
} =vMFCp;mv  
catch(Exception e){e.printStackTrace ();} 2J =K\ L  
~U#afGH$  
G=!1P]M{  
} q'77BRD3  
:}0y[qc3  
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public static void main(String[] args) BB5(=n+  
{ @dQIl#  
new TestMethod(); C Fq3  
} e.jrX;;$!&  
} z9pv|  
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