http断点续传简单实现（java)

/* kxH` c  
**SiteFileFetch.java uA[c$tBe  
*/ H3>49;`  
package NetFox; (jp!q,)  
import java.io.*; :\F1S:&P  
import java.net.*; {oftZXwf  
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public class SiteFileFetch extends Thread { %'w?fqk  
@L,4JPk  
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SiteInfoBean siteInfoBean = null; //文件信息Bean .%G>z"Xx  
long[] nStartPos; //开始位置 SpC6dkxD\  
long[] nEndPos; //结束位置 u
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FileSplitterFetch[] fileSplitterFetch; //子线程对象 $W;f9k@C!  
long nFileLength; //文件长度 jB"IJ$cD  
boolean bFirst = true; //是否第一次取文件 %7hf6Xo=  
boolean bStop = false; //停止标志 ,<s/K  
File tmpFile; //文件下载的临时信息 (yK@(euG  
DataOutputStream output; //输出到文件的输出流 t2LX@Q"  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） [x{Ai( /T^  
public SiteFileFetch(SiteInfoBean bean) throws IOException M(U<H;Csk  
{ 4DgH/Yo  
siteInfoBean = bean; ]%2y`Jrl^W  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); f=hT o!i  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); VOSq%hB  
if(tmpFile.exists ()) 
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{ uGpLh0  
bFirst = false; 8RA  
read_nPos(); -2B3 xIZJ  
} QV[#^1  
else 25Uw\rKeO  
{ ER,!`C]  
nStartPos = new long[bean.getNSplitter()]; lO
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nEndPos = new long[bean.getNSplitter()]; <nU8.?\?~  
} $1y8X K7r  
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} 43,baeG  
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public void run() L/?jtF:o  
{ 7/
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//获得文件长度 0at['zw  
//分割文件 }R!t/8K  
//实例FileSplitterFetch Ou`;HN;
[  
//启动FileSplitterFetch线程 4I8QM&7  
//等待子线程返回 wvmcD%   
try{ $It3}?>C'  
if(bFirst) '{w[).c.  
{ k=4C"   
nFileLength = getFileSize(); l5nm.i<M  
if(nFileLength == -1) zF@[S  
{ qVW3oj<2  
System.err.println("File Length is not known!"); WK5B8u*<  
} 4\E1M[6  
else if(nFileLength == -2) u'T?e
+=  
{ `=lo.c  
System.err.println("File is not access!"); /?NfU.+K  
} @E4ya$A)F  
else Q`!^EyRA:^  
{ M5:j)oW  
for(int i=0;i<nStartPos.length;i++) ~ycWcZi>  
{ f#McTC3C  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); wb>"'%  
} qr(t_qR&  
for(int i=0;i<nEndPos.length-1;i++) i9Eh1A3Y  
{ AC*SmQ\>!  
nEndPos = nStartPos[i+1]; $DdC|
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} R|92T*h  
nEndPos[nEndPos.length-1] = nFileLength; pJJO
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} lNz1|nS(Kd  
} Y;"jsK{$  
y&V%xE/  
+4+czfz  
//启动子线程 ^CK D[s  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; hU3sEOm>  
for(int i=0;i<nStartPos.length;i++) :F_>`{  
{ '~VF
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fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 6_&S ?yA  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), "E@A~<RKP  
nStartPos,nEndPos,i); z31g"  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); nRyx2\Py+  
fileSplitterFetch.start(); 6rM{r>  
} RivhEc1h%  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), mV0u:ws  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 7x]q>Y8T  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", -jzoGzC3  
nEndPos = " + nFileLength); U]W"  
// fileSplitterFetch[nPos.length-1].start(); 
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//等待子线程结束 < lUpvr  
//int count = 0; b2H-D!YO^  
//是否结束while循环 0p+36g  
boolean breakWhile = false; a'g&1N0Rc  
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while(!bStop) CzIs_/  
{ Cj=_WWo  
write_nPos(); o;21|[z  
Utility.sleep(500); Tb!FO"o  
breakWhile = true; yg4#,4---b  
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,  
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for(int i=0;i<nStartPos.length;i++) 5jv*C]z  
{ ]Ot=At  
if(!fileSplitterFetch.bDownOver) N_G84wxx  
{ 4aKppj  
breakWhile = false; RXo6y(^  
break; \t%iUZ$  
} '#>Fe`[  
} :2V|(:^'  
if(breakWhile) &Xc=PQ:I  
break; At'M? Q@v  
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//count++; <g&.UW4  
//if(count>4) 2PSkLS&IM  
// siteStop(); }=B~n0  
} ,J
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System.err.println("文件下载结束！"); =:t<!dp  
} 1<cx!=w'  
catch(Exception e){e.printStackTrace ();} ; K,5qs  
} |)br-?2  
A H=%6oT2  
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//获得文件长度 RN}joKV  
public long getFileSize() $$SJLV
  
{
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int nFileLength = -1; +_25E.>ml  
try{ KdD~;Ap$  
URL url = new URL(siteInfoBean.getSSiteURL()); TRJTJM_k  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); M`7[hr  
httpConnection.setRequestProperty("User-Agent","NetFox"); n/`!G?kvI  
)L7[;(gQ  
@ 'c(q=K;  
int responseCode=httpConnection.getResponseCode(); !/ dH"h  
if(responseCode>=400) XB@i
{/6K  
{ [XH,~JZJj  
processErrorCode(responseCode); CpK:u! Dn  
return -2; //-2 represent access is error I!}V+gu=  
} (N/-blto  
:S}ZF$ $j%  
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String sHeader; zqURnsJ  
';}:*nZ//_  
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for(int i=1;;i++) C(UWir3mW?  
{ !Pt4\  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Spu;  
//Utility.log(in.readLine()); l8:!{I?s=  
sHeader=httpConnection.getHeaderFieldKey(i); -x:7K\=$SX  
if(sHeader!=null) kd_!S[  
{ !T2{xmHKv$  
if(sHeader.equals("Content-Length")) $5\!ws<cZ  
{
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nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); !&cfX/y8  
break; [k75+#'  
} y
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} Qmb+%z  
else epG]$T![  
break; 1]Cbi7  
} xFJT&=Af W  
} 4sX?O4p  
catch(IOException e){e.printStackTrace ();} -m[ tYp,q  
catch(Exception e){e.printStackTrace ();} !vVW8hbp  
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Utility.log(nFileLength); =[[I<[BZq  
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return nFileLength; >o%X;U 3  
} vbX.0f "n  
p!)PbSw#  
2pvby`P4  
//保存下载信息（文件指针位置） S4c-i2Rq  
private void write_nPos() 9UV}`UM3V  
{ L@jpid95  
try{ 
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output = new DataOutputStream(new FileOutputStream(tmpFile)); e>6W ^ )  
output.writeInt(nStartPos.length); w~+\Mfz  
for(int i=0;i<nStartPos.length;i++) Jr%F#/  
{ WnU2.:  
// output.writeLong(nPos); qrjSG%i~J7  
output.writeLong(fileSplitterFetch.nStartPos);  j=G  
output.writeLong(fileSplitterFetch.nEndPos); 
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} YMy**  
output.close(); >wL!`:c'"  
} B*E"yB\NV  
catch(IOException e){e.printStackTrace ();} I[gPW7&S@  
catch(Exception e){e.printStackTrace ();} 8r:T
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} smn(q)tt  
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//读取保存的下载信息（文件指针位置） 8|$g"?CU  
private void read_nPos() qT:`F  
{ +?*.Emzl@  
try{ J5O/c,?g  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Hwtoa,  
int nCount = input.readInt(); |/c-~|%  
nStartPos = new long[nCount]; T+t7/PwC;  
nEndPos = new long[nCount]; W5e>Z&&  
for(int i=0;i<nStartPos.length;i++) A|@d{g  
{ .W$9nbly  
nStartPos = input.readLong(); :Ig9n:  
nEndPos = input.readLong(); YHke^Ind
 
} ux*G*QZ  
input.close(); *b!.9pK  
} 7/fJQM  
catch(IOException e){e.printStackTrace ();} T,Q7 YI  
catch(Exception e){e.printStackTrace ();} "vkM*HP  
} uZ@qlq8  
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private void processErrorCode(int nErrorCode) 7
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{ ^^24a_+2  
System.err.println("Error Code : " + nErrorCode); WP Gp(Xw  
} ar'VoL}  
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//停止文件下载 <VQ@I  
public void siteStop() blP8"(U  
{ |oX9SUl  
bStop = true;  BPKrRex  
for(int i=0;i<nStartPos.length;i++) >{A)d<  
fileSplitterFetch.splitterStop(); D5xTuv9T  
:uqEGnEut  
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} 6/p9ag]  
} M?<iQxtyb}  
//负责部分文件的抓取 .:B0(4Mj  
**FileSplitterFetch.java {K|ds($ 5  
*/ >MhZ(&iD  
package NetFox; BLt_(S?Z`  
(JE&1 @  
/}%C'  
import java.io.*; q[Ey!h)xq  
import java.net.*; Nr"GxezU+A  
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public class FileSplitterFetch extends Thread { Y(ClG*6 ++  
/Tw $}8  
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String sURL; //File URL EiDpy#f}  
long nStartPos; //File Snippet Start Position V' i@N  
long nEndPos; //File Snippet End Position zxd<C
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int nThreadID; //Thread's ID _g D9oK  
boolean bDownOver = false; //Downing is over 31M'71s  
boolean bStop = false; //Stop identical $bBUL C  
FileAccessI fileAccessI = null; //File Access interface CSwB+yN  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException onS4ZE3B  
{ *13-)yfd  
this.sURL = sURL; ~H[_=  
this.nStartPos = nStart; V,\}|_GY  
this.nEndPos = nEnd; .#K\u![@N  
nThreadID = id; .%\||1F<  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 RaymSh  
} DGz}d,ie  
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public void run() 5l(@p7_+  
{ ~X'hRNFx~  
while(nStartPos < nEndPos && !bStop) (9] =;)  
{ S3QX{5t\  
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try{ !NKPy+v  
URL url = new URL(sURL); w2`JFxQ^x  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); g(S4i%\  
httpConnection.setRequestProperty("User-Agent","NetFox"); |uRYejj#j  
String sProperty = "bytes="+nStartPos+"-";  ZLf(m35  
httpConnection.setRequestProperty("RANGE",sProperty); A9Pq}3U  
Utility.log(sProperty); K!-iDaVI  
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InputStream input = httpConnection.getInputStream(); =~dXP  
//logResponseHead(httpConnection); K8QEHc:  
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byte[] b = new byte[1024]; jT-tsQ .,  
int nRead; Go~3L8 '  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) :/fT8KCwo  
{ :D !/.0  
nStartPos += fileAccessI.write(b,0,nRead); F7=&CW 0  
//if(nThreadID == 1) k4"O}jQO  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); _gCi@uXS3  
} Rp}Sm,w(  
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Utility.log("Thread " + nThreadID + " is over!"); COH>B1W@  
bDownOver = true; &>ykkrY  
//nPos = fileAccessI.write (b,0,nRead); _w%{yF6   
} A{DE7gp!
 
catch(Exception e){e.printStackTrace ();} Z[\nyj  
} }|c-i.0=
 
} }
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//打印回应的头信息 id1gK(F8H  
public void logResponseHead(HttpURLConnection con) 'puiahA  
{ i/,IG+4vI  
for(int i=1;;i++) 2rS`ViicD  
{ CraD  
String header=con.getHeaderFieldKey(i); v0pev;C  
if(header!=null) x!?$y_t  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 0j' Xi_uM  
Utility.log(header+" : "+con.getHeaderField(header)); Y1{*AV6ev6  
else eTY(~J#'  
break;  `EVy  
} {iTA=\q2O  
} 5F1P|t#  
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public void splitterStop() u#$sO;8s  
{ ]"\sd"  
bStop = true; Cs^'g'  
} w?R#ly  
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@ |(Tg  
} MQo/R,F }  
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q]P$NeEiZ"  
/* uCf _O~  
**FileAccess.java *p^*>~i9)  
*//文件访问(定位，写) K|rG&#1J  
package NetFox; 7x(z  
import java.io.*; 0?'v|5}  
/f!ze|  
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public class FileAccessI implements Serializable{ iE"+-z\U  
z'k@$@:0XD  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 {6;S= 9E\
 
RandomAccessFile oSavedFile; oJ0ZZu?{D  
long nPos; mX@!O[f%9e  
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public FileAccessI() throws IOException 5?Rzyfwk|  
{ V<t!gT#&o!  
this("",0); SD1M`PI  
} jg(cpo d  
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public FileAccessI(String sName,long nPos) throws IOException 1u_< 1X3  
{ "pQ)5/e  
oSavedFile = new RandomAccessFile(sName,"rw");  Y?IXV*J  
this.nPos = nPos; p}yp!(l  
oSavedFile.seek(nPos); b3+F~G-I"  
} A04E <nr  
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public synchronized int write(byte[] b,int nStart,int nLen) <;zcz[~  
{ dZ,~yV  
int n = -1; tP|ox]  
try{ Xm~N Bt  
oSavedFile.write(b,nStart,nLen); j>|mpfU  
n = nLen; m+pFU?<|  
} |j!U/n.%w  
catch(IOException e) $6*6%T5}  
{ x^6b$>1  
e.printStackTrace (); Q=F4ZrNqD  
} ^wb$wtL('  
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return n; N/r8joi#  
} aQL$?,  
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} I{uwT5QT-  
H.!\j&4j  
Bx ru7E"  
/* &>
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**SiteInfoBean.java Og9:MFI  
*/ vptBDfzz  
package NetFox; _"S1>s)X?j  
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public class SiteInfoBean { W=!di3IA  
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c"`CvQO64  
private String sSiteURL; //Site's URL fzW!-  
private String sFilePath; //Saved File's Path 71OQ?fc  
private String sFileName; //Saved File's Name ,g{Ob{qT  
private int nSplitter; //Count of Splited Downloading File 1ac;6`  
G q2@37
U  
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public SiteInfoBean() vALH!Kh  
{//nSplitter的缺省值为5 x\'95qU  
//default value of nSplitter is 5 #A9rI;"XI  
this("","","",5); oO&R3z
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} *QP+p,L*  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) gEkH5|*Y  
{ E}8wnrxf  
sSiteURL= sURL; 3 cF4xUIZ  
sFilePath = sPath; bTW# f$q:4  
sFileName = sName; m"RSDM!  
this.nSplitter = nSpiltter; !6l}s$1i|  
rtZEK:.#  
V D.T=(  
} fW3NH7aUG  
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N2$uw@s  
public String getSSiteURL() %O\zYtQR  
{ KU*XRZu)  
return sSiteURL; Q;y)6+VU4  
} 3u~V&jl  
%v,a3^Qu  
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public void setSSiteURL(String value) P|QM0GI  
{ 4~Jg\@  
sSiteURL = value; +vO;J  
} /DoSU>%hK  
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public String getSFilePath() ^H~g7&f9?N  
{ ISi^BFU  
return sFilePath; W|AK"vf  
} GVld]ioycG  
agp7zw=N  
EdC/]  
public void setSFilePath(String value)  } @4by<  
{ TWSx9ii!M:  
sFilePath = value; JbLHW26pl  
} i.0.oy>  
W>y&  
}5]7lGR  
public String getSFileName() 9oTtH7%  
{ /#g P#Z%  
return sFileName; B*AB@  
} o3(:R0  
JXF0}T)C  
!YENJJ  
public void setSFileName(String value) %ZM"c  
{ 1}ws@hU  
sFileName = value; -xL^UcG0  
} |wGmu&fY  
^:Fj+d  
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public int getNSplitter() -SUK[<=X  
{ aXh~w<5F  
return nSplitter; )8*}-z  
} p&k%d, *  
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public void setNSplitter(int nCount) PM`iqn)@  
{ ;C,t`(  
nSplitter = nCount; JiFB<Q\  
} &.[I}KH|B  
} 4n6t(/]b<  
,C0D|q4/!.  
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/* =hi{J M  
**Utility.java qijQRxS  
*/ ,Rdw]O  
package NetFox; !24PJ\~I  
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public class Utility { z^u*e  
/B)`pF.n  
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public Utility() lx:.9>  
{ KpC!C9  
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} wWQt  
C2H2*"  
//线程睡眠 zx7A}rs3oX  
public static void sleep(int nSecond) $g_|U:,  
{ m2[]`Ir^@  
try{ 0( q:K6zI}  
Thread.sleep(nSecond); |cgc^S/~H  
} WOi+y   
catch(Exception e) }U|0F#0$  
{ T'!p{Fbg;  
e.printStackTrace (); HutQ
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} 4Q:r83#  
} +<bvh<]Od  
^
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//日志 KzQuLD(e  
public static void log(String sMsg) rlY n"3%  
{ jEn9T  
System.err.println(sMsg); $bl<mG%#9  
} -+[~eqRB  
>?[?W|k7V  
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public static void log(int sMsg) OV|n
/~  
{ l~mj>$  
System.err.println(sMsg); Zi{vEI]  
} U#:N/ts*(  
} X 4\V4_  
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/* UJ><B"  
**TestMethod.java b8**M'k  
*/ %E[ $np>  
package NetFox; 8ib e#jlg  
|

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public class TestMethod { >Se-5QtLcf  
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/0b7"Kr  
public TestMethod() N ;Cs? C  
{ ///xx/weblogic60b2_win.exe ySHpN>U  
try{ 
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SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); iy|;xBI,  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); `NfwW
:  
SiteFileFetch fileFetch = new SiteFileFetch(bean); JA% y{Wb  
fileFetch.start(); 08/Tk+  
} q);oO\<  
catch(Exception e){e.printStackTrace ();} 0{/
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`+i/rc1.  
} :-$TD('F  
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zEh&@{u?  
public static void main(String[] args) `
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{ b^A7R{G7  
new TestMethod(); q8MyEoc:n  
} \+Y5b}  
} ^UBzX;|p  
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