http断点续传简单实现（java)

/* 8.{5c6G  
**SiteFileFetch.java wcsUb9(  
*/ C[& \Xq  
package NetFox; ,hT t]w  
import java.io.*; KNQX\-=  
import java.net.*; b0PF7PEEQ  
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public class SiteFileFetch extends Thread { V. =!^0'A  
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SiteInfoBean siteInfoBean = null; //文件信息Bean (gvaYKvr  
long[] nStartPos; //开始位置 "CT'^d+  
long[] nEndPos; //结束位置 QC \8Zy  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 dL |D  
long nFileLength; //文件长度 ,K+K`"Oy  
boolean bFirst = true; //是否第一次取文件 (/v(.t  
boolean bStop = false; //停止标志 9{'GrL  
File tmpFile; //文件下载的临时信息 -+Kx^V#'R  
DataOutputStream output; //输出到文件的输出流 8"N<g'Yl,  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） w%S\)wjS  
public SiteFileFetch(SiteInfoBean bean) throws IOException [,8@oM#  
{ a7%5Qg9B;  
siteInfoBean = bean; nP0|nPWz#  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 9,`WQ+OI  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); %%G2w63M  
if(tmpFile.exists ()) (O\5gAx  
{  zy  
bFirst = false; $FNj>1  
read_nPos(); ;} Ty b  
} Z8z.Xn  
else ",w@_}z:  
{ .,o=#  
nStartPos = new long[bean.getNSplitter()]; crz )F"  
nEndPos = new long[bean.getNSplitter()]; aVNRhnM  
} *q=pv8&*s  
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} =n cu#T]  
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public void run() Ha[Bf*  
{ brl(7_2  
//获得文件长度 Y]Vt&*{JV  
//分割文件 u+&BR1)C  
//实例FileSplitterFetch
7!]$XGz[  
//启动FileSplitterFetch线程 0x4Xs  
//等待子线程返回 K``MS  
try{ )U`
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if(bFirst) \5_+6  
{ &;&i#ZO  
nFileLength = getFileSize(); (]w_}E]N  
if(nFileLength == -1) Oq7M1|{  
{ "4<RMYQ  
System.err.println("File Length is not known!"); Qo4]_,kR  
} kl?U2A.=  
else if(nFileLength == -2) re2M!m6k5  
{ 4`I2tr  
System.err.println("File is not access!"); S*Qip,u  
} %\6|fKB4<  
else :"5
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{ n!2"pRIi  
for(int i=0;i<nStartPos.length;i++) AME3hA  
{ )^qM%k8  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); cV\(Z6u  
} xdFm-_
\-  
for(int i=0;i<nEndPos.length-1;i++) |F=!0Id<  
{ YiJnh47  
nEndPos = nStartPos[i+1]; }%c2u/PQ  
} ^ |z|kc
 
nEndPos[nEndPos.length-1] = nFileLength; O:IU|INq8  
} ai)S:2  
} Ew5(U`
]  
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//启动子线程 umaF}}-Q{  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ]i(tou-[i  
for(int i=0;i<nStartPos.length;i++) '-oS=OrZ  
{ v8Vw.Ce`f  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), N7Kq$G2O  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 9]<p  
nStartPos,nEndPos,i); Se.\wkl#Y  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); #k&"Rv;,  
fileSplitterFetch.start(); VCSHq&p8  
} i ?&t@"'  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), twv|,kM  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); :hJHjh  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", n+QUT   
nEndPos = " + nFileLength); Ebw1 %W KC  
// fileSplitterFetch[nPos.length-1].start(); cKJf0S:cx-  
cXU8}>qY7  
@<=xfs  
//等待子线程结束 Uy2NZ%rnt  
//int count = 0; "(zvI>A  
//是否结束while循环 )h6hN"#V5  
boolean breakWhile = false; gHdNqOy c  
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while(!bStop) VT8PV5z  
{ ?oana%  
write_nPos(); gqV66xmJ3  
Utility.sleep(500); m5m}RWZ#  
breakWhile = true; B>Tfyo  
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for(int i=0;i<nStartPos.length;i++) sU!h^N$  
{ 7#d>a=$h  
if(!fileSplitterFetch.bDownOver) Cuu yG8  
{ d` %8qLIW  
breakWhile = false; 1/X@~  
break; r<VZEbm)  
} kW#,o9f\  
} #hG0{_d7  
if(breakWhile) 1N6.r:wg)%  
break; h DpIwzJ  
7=i8$v&GX  
-AnQZy  
//count++; wNo2$>*  
//if(count>4) Q6blX
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// siteStop(); (3cJ8o>&  
} hgIqr^N9  
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System.err.println("文件下载结束！"); mApn[)?tv  
} Y-!~x0-H  
catch(Exception e){e.printStackTrace ();} \|e>(h!l;  
} rPhx^ QKH2  
PD #9Z=Hj  
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//获得文件长度
"NEg]LB5  
public long getFileSize() }L mhM  
{ !dnCrR  
int nFileLength = -1; <A|X4;  
try{ 3y^PKIIrt  
URL url = new URL(siteInfoBean.getSSiteURL()); %Ms"LoK  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); X$*MxMNs  
httpConnection.setRequestProperty("User-Agent","NetFox"); dbn9t7'{  
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int responseCode=httpConnection.getResponseCode(); %+ln_lgD:  
if(responseCode>=400) ot\  FZ  
{ UWU(6J|Fk  
processErrorCode(responseCode); q4u,pm,@  
return -2; //-2 represent access is error xgDd5`W  
} 5OEo(&  
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#IJm*_J<  
String sHeader; 4
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*JnY0xP  
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for(int i=1;;i++) 7Qdf#DG  
{ U ?iw  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); /q|r!+  
//Utility.log(in.readLine()); `wI$  
sHeader=httpConnection.getHeaderFieldKey(i); jej.!f:H  
if(sHeader!=null) ~[8n+p+&X  
{ rR Kbs@1M  
if(sHeader.equals("Content-Length")) ^}SP,lg'  
{ JJ:pA_uX  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); SjosbdD  
break; Vz.G!*>Dg  
} 5D]3I=kj  
} ak,KHA6u  
else ^aG$9N<\  
break; e p jb  
} 7eNLs  
} n[S-bzU^t  
catch(IOException e){e.printStackTrace ();} \;XDPC j  
catch(Exception e){e.printStackTrace ();} ./]xn  
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Utility.log(nFileLength); <`$svM  
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return nFileLength; m+UWvUB)  
} G2$<Q+UYs?  
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//保存下载信息（文件指针位置） A<h^.{  
private void write_nPos() ai7R@~O:_k  
{ "D\>oFu  
try{ BGd# \2  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Bd'X~Vj<  
output.writeInt(nStartPos.length); ?"F9~vx&G  
for(int i=0;i<nStartPos.length;i++) !dQmg'_V  
{ nx
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// output.writeLong(nPos); ~<N9ckK  
output.writeLong(fileSplitterFetch.nStartPos); =K)[3mXX  
output.writeLong(fileSplitterFetch.nEndPos); {EfA#{x  
} eOoqH$ i  
output.close(); i)iK0g"2  
} g6 H}a  
catch(IOException e){e.printStackTrace ();} mjQZ"h0  
catch(Exception e){e.printStackTrace ();} 6i+<0b}!/  
} ~dO+kD  
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//读取保存的下载信息（文件指针位置） (ZPl~ZO  
private void read_nPos() !>:SPt l  
{ _<E.?K$gbU  
try{ ZZ>"LH  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); {|d28!8w  
int nCount = input.readInt(); ^B_SAZ&%%  
nStartPos = new long[nCount]; kYhV1I  
nEndPos = new long[nCount];
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for(int i=0;i<nStartPos.length;i++) F?z:[1(:  
{ vfd<qdi3p(  
nStartPos = input.readLong(); )3IUKz%\6p  
nEndPos = input.readLong(); ,i jB3J  
} oVTXn=cYDp  
input.close(); uTdx`>M,O  
} "MvSF1  
catch(IOException e){e.printStackTrace ();} 4se6+oJe  
catch(Exception e){e.printStackTrace ();} E<ILZpP
 
} 1> v(&;K  
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private void processErrorCode(int nErrorCode) 5tI#UBha  
{ zfD@/kU  
System.err.println("Error Code : " + nErrorCode); &cWC&Ws"  
} {wDq*va  
+/[L-&,  
 bUsX~R-  
//停止文件下载 *rg
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public void siteStop() ?f$U8A4lp  
{ -Qn l)JB  
bStop = true; 4VHWoN"U  
for(int i=0;i<nStartPos.length;i++) dWx@<(`OC  
fileSplitterFetch.splitterStop(); i z
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ih|;H:"^  
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} x5Ue"RMl+
 
} :GN++\1pw  
//负责部分文件的抓取 Z2L7US-  
**FileSplitterFetch.java MQQQaD:v  
*/ NEUr w/  
package NetFox; e^<'H  
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import java.io.*; m-6&-G#  
import java.net.*; ~ulcLvm:i  
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public class FileSplitterFetch extends Thread { m*L5xxc!  
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%)72glB  
String sURL; //File URL Ge @qvP_  
long nStartPos; //File Snippet Start Position ^AShy`o^X  
long nEndPos; //File Snippet End Position Z l;TS%$  
int nThreadID; //Thread's ID 1:iB1TclP  
boolean bDownOver = false; //Downing is over ny%$BQM=  
boolean bStop = false; //Stop identical (j~T7og  
FileAccessI fileAccessI = null; //File Access interface =:Yrb2gP_\  
VP~(;H5%  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException lUaJC'~p  
{ 33SCHQ  
this.sURL = sURL; l}iQ0v@  
this.nStartPos = nStart; 3GNcnb  
this.nEndPos = nEnd; =it@U/  
nThreadID = id; jXVvVv  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 qqJghV$Oj  
} M}j[{wW3  
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public void run() em95ccs'-  
{ =W;e9 6#  
while(nStartPos < nEndPos && !bStop) ,N_/J4Us  
{ wMw}3qX$j  
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try{ v k=|TE  
URL url = new URL(sURL); oeZUd}P  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); HYmUD74FR  
httpConnection.setRequestProperty("User-Agent","NetFox"); lu6iU  
String sProperty = "bytes="+nStartPos+"-"; t`'jr=e,~  
httpConnection.setRequestProperty("RANGE",sProperty); LXWI'nxV  
Utility.log(sProperty); qcouZO  
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InputStream input = httpConnection.getInputStream(); xFekSH7[F  
//logResponseHead(httpConnection); (c&%1bJ  
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byte[] b = new byte[1024]; ZqdoYU'  
int nRead; s_}6#;  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ZPY&q&R  
{ >&Oql9_  
nStartPos += fileAccessI.write(b,0,nRead); u;]xAr1  
//if(nThreadID == 1) `a:3S@n(}  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); k$ T  
} ;Xa N  
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Utility.log("Thread " + nThreadID + " is over!"); ar\K8mj  
bDownOver = true; *7-rm  
//nPos = fileAccessI.write (b,0,nRead); ' tHa5`  
}  VM:|I~gJ  
catch(Exception e){e.printStackTrace ();} }JWkV1  
} uO-|?{29  
} ,[T/O\k  
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$=Ns7Sbup  
//打印回应的头信息 zd)QCq  
public void logResponseHead(HttpURLConnection con) ?G,gP
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{ .j
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for(int i=1;;i++) Qclq^|O0  
{ UX[s5#  
String header=con.getHeaderFieldKey(i); _G-y{D_S&  
if(header!=null) RjH68=n  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); dWQB1Y*N  
Utility.log(header+" : "+con.getHeaderField(header)); !V(r p80  
else s*_fRf:  
break; _~MX~M3MB  
} wPm  
} |`Noj+T47I  
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public void splitterStop() /:Gy .  
{ 'e' p`*  
bStop = true; 7i{(,:  
} 8!cHRtqK  
'<YBoU{e*  
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} Ncsh{.
  
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/* },#7  
**FileAccess.java p}h.2)PO  
*//文件访问(定位，写) :\qapFV  
package NetFox; +
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import java.io.*; x~R,rb   
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public class FileAccessI implements Serializable{ '2i !RT-  
rm9>gKN;#  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 q^sZP\i,*;  
RandomAccessFile oSavedFile; 4oH ,_sr  
long nPos; :{ZwzJ  
Q!qD3<?5  
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public FileAccessI() throws IOException ppNMXbXR  
{ NN=^4Xpc:  
this("",0); 23i2y
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} G`kz 0Vk  
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public FileAccessI(String sName,long nPos) throws IOException "O0xh_Nr  
{ 8{/.1:  
oSavedFile = new RandomAccessFile(sName,"rw"); D>7J[ Yxg-  
this.nPos = nPos; J{prI;]K  
oSavedFile.seek(nPos); OqDP{X:  
} Jy%?"wn  
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+)WU:aKI  
public synchronized int write(byte[] b,int nStart,int nLen) JffaT_"\  
{ -,b+tC<V)0  
int n = -1; =#[oi3k  
try{ ;m#4Q6k)V?  
oSavedFile.write(b,nStart,nLen); prN+{N8YC  
n = nLen; q)Nw$dW<  
} b^C27s  
catch(IOException e)
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{ .kg 3>*  
e.printStackTrace (); *j&)=8Y|   
} t1o 6;rK  
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return n; WEe7\bWF  
} c+e?xXCEAz  
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} eBnx$  
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6(d6Uwc`  
/* <A8>To<  
**SiteInfoBean.java 6V]m0{:E  
*/ :,aY|2si  
package NetFox; Sk>=C0f:  
!|xB>d q?  
t~j6wsx;  
public class SiteInfoBean { `3i>e<m~  
<MkvlLu((o  
~Ay)kv;  
private String sSiteURL; //Site's URL HrvyI)4{  
private String sFilePath; //Saved File's Path WIf.;B)L  
private String sFileName; //Saved File's Name :M6v<Kg{;  
private int nSplitter; //Count of Splited Downloading File =dDPQZEin  
`sT;\  
,P`NtTN-  
public SiteInfoBean() jL^@;"/XhC  
{//nSplitter的缺省值为5 {<gv1Yht  
//default value of nSplitter is 5 >x;\H(g  
this("","","",5); aF^NYe  
} 94ruQ/   
iLuC_.'u=  
}8
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) (vZ-0Ep}  
{ m =b7 r  
sSiteURL= sURL; i83
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sFilePath = sPath; oC>J{z  
sFileName = sName; mXp#6'a  
this.nSplitter = nSpiltter; zT78FliY6  
=;uMrb4  
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} d2#
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ai sa2#  
public String getSSiteURL() pvyEs|f=%  
{ #\l
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return sSiteURL; F5 ]<=i  
} j9[I6ko5'  
$YEm(:v$  
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public void setSSiteURL(String value) mYgfGPF`  
{ Mi8)r_l%O  
sSiteURL = value; p lnH  
} +mVAmG@  
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)xV37]  
public String getSFilePath() ]E<Z5G1HD  
{ 'l.tV7  
return sFilePath; )dhR&@r*w  
} w!20  
Ldz]FB|  
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public void setSFilePath(String value) *{w0=J[15  
{ M<w
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sFilePath = value; K/ On|C  
} !\7`I}:  
'37 {$VHw  
J#Hh4Kc  
public String getSFileName() H **tMq  
{ uH9Vj<E$K  
return sFileName; O0qG 6a  
} [G|.  
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public void setSFileName(String value) <x^$Fu
 
{ ~o^|>]  
sFileName = value; H:~p5t  
}  9BtGzI\  
b}R_@_<u  
~rBFP)  
public int getNSplitter() _ l`F}v  
{ rV%68x9  
return nSplitter; _Rii19k  
} ,_kw}_n=  
jy!]MAP#Gk  
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public void setNSplitter(int nCount) Df4O~j$U"s  
{ &IUA[{o~e  
nSplitter = nCount; ~][~aEat;V  
} 03fOm  
} /(BS<A  
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#Zm`*s`  
/* PK:Lv15"r  
**Utility.java eVfD&&@  
*/ y]jx-wc3O  
package NetFox; );.$`0  
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public class Utility { b\(f
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public Utility() .4CDQ&B0K  
{ m0bxVV^DK!  
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} !.j{vvQ/  
y$R8J:5f  
//线程睡眠 W/2y;@  
public static void sleep(int nSecond) ]vQa~}  
{ _R\F
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try{ ?C2(q6X+s  
Thread.sleep(nSecond); Wa^Wn +r  
} #'&-S@/nQs  
catch(Exception e) -w"I  
{ o!BC
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e.printStackTrace (); %>*?uO`z[  
} UJ}}H}{  
} R@3HlGuRKw  
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//日志 $Lstq_x+  
public static void log(String sMsg) ejV`W7U  
{ YdCl  
System.err.println(sMsg); (sKg*G2  
} j-1V,V=  
~%*l>GkP*  
U%@
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public static void log(int sMsg) ">Qxb.Y}  
{ mx}5":}  
System.err.println(sMsg); h~
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} \ZcI{t'a  
} >k"O3Pc@  
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/* QwhO/  
**TestMethod.java |^8ND#x  
*/ rd->@s|4mT  
package NetFox; En&7e  
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_K#7#qp2  
public class TestMethod { K7&]|^M9  
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6h/!,j0:t_  
public TestMethod() l5w^rj  
{ ///xx/weblogic60b2_win.exe tQzbYzG
b7  
try{ @M\JzV4 A[  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); C,W@C  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); c:K/0zY  
SiteFileFetch fileFetch = new SiteFileFetch(bean); zdJPMNHg  
fileFetch.start(); Nt8"6k_  
} \*CXXp`  
catch(Exception e){e.printStackTrace ();} c_
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)$^xbC#j`3  
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} %t&Lq}e  
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public static void main(String[] args) $CB&>?~  
{ -J63'bb7oi  
new TestMethod(); bsu?Q'q  
} eFs5l  
} |5;,]lbt  
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