http断点续传简单实现（java)

/* ZAv,*5&<  
**SiteFileFetch.java  Fy`(BF\  
*/ iz8Bf;  
package NetFox; zA$k0p  
import java.io.*; E=e*VEjy  
import java.net.*; l^|UCgRn  
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k 8UO9r[  
public class SiteFileFetch extends Thread { 1u: gFUb  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 5&v~i\Q  
long[] nStartPos; //开始位置 RRRCS]y7$t  
long[] nEndPos; //结束位置 MYla OT  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ^Wc@oa`  
long nFileLength; //文件长度 0Uo\wyd  
boolean bFirst = true; //是否第一次取文件 FrTi+& <  
boolean bStop = false; //停止标志 AWP"b?^G|  
File tmpFile; //文件下载的临时信息 ]|MEx{BG-  
DataOutputStream output; //输出到文件的输出流 A%`[mc]4#  
k\WR ]  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 1#.>a$>  
public SiteFileFetch(SiteInfoBean bean) throws IOException G'6@+$ppS  
{ Qp/QaVQ+  
siteInfoBean = bean; BRlT7grgq  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 2^^`n1?'  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 9?0^ap,T  
if(tmpFile.exists ()) =at@Vp/y  
{ vg3=8>#  
bFirst = false; _9=Yvc=  
read_nPos(); &Q>k7L!  
} !P)O(i=  
else [-\%4  
{ ^:#D0[  
nStartPos = new long[bean.getNSplitter()]; h{
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nEndPos = new long[bean.getNSplitter()]; >sK!F$  
} f>W-  
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} |QU <e  
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public void run() f7=((
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{ {5F-5YL+>  
//获得文件长度 ^ q<v{_  
//分割文件 :a$\/E=  
//实例FileSplitterFetch m|{3),#V  
//启动FileSplitterFetch线程 ~C>?W[Y  
//等待子线程返回 w+yC)Rmz  
try{ F)W:  
if(bFirst) !{^PO<9  
{ R~)\3] "2m  
nFileLength = getFileSize(); @7?#Y|`  
if(nFileLength == -1) DpUbzr41+k  
{ {vuZ{IJa  
System.err.println("File Length is not known!"); ;j^H)."A\  
} E=>FjCsu<-  
else if(nFileLength == -2) .ox8*OO<  
{ %d?cP}V  
System.err.println("File is not access!"); 1XD,uoxB  
} a{R%#e\n  
else P%#<I}0C  
{ hRs&t,{&  
for(int i=0;i<nStartPos.length;i++)  CCL  
{ QKr,g  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ^~3SSLS4"  
} r]b_@hT',  
for(int i=0;i<nEndPos.length-1;i++) ~S8*t~  
{ !t gi  
nEndPos = nStartPos[i+1]; mT.u0KUIy  
} [/e<l&y  
nEndPos[nEndPos.length-1] = nFileLength; JwAYG5W  
} Ib+Y~ XYR  
} qYlhlHD  
T~Gvp0r}h  
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//启动子线程 #MRMNL@   
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; )pq;*~IBI  
for(int i=0;i<nStartPos.length;i++) Bh;7C@dq  
{ w-Da~[J  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), vTJ}8  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), %k'!Iq+  
nStartPos,nEndPos,i); @Ub"5Fl4  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); J/[=p<I)  
fileSplitterFetch.start(); 0cJWJOj&  
} yuat" Pg  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), @te
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); .=X}cJ]`[  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", EUN81F?  
nEndPos = " + nFileLength); $shoasSuI  
// fileSplitterFetch[nPos.length-1].start(); :9^;Qv*  

&(xH$htv1  
i 7x7xtq  
//等待子线程结束 L{h%f4Du#  
//int count = 0; A29gz:F(  
//是否结束while循环 |j#C|V%kV  
boolean breakWhile = false; m]5Cq6  
F.w5S!5Q  
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while(!bStop) FW/W%^  
{ STxKE %l  
write_nPos(); 9J9)AV  
Utility.sleep(500); sB c (gr  
breakWhile = true; Q\ U:~g3  
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for(int i=0;i<nStartPos.length;i++) ?kB2iU_f+  
{ N4L|;?  
if(!fileSplitterFetch.bDownOver) j(RWO  
{ j^^Ap  
breakWhile = false; =jX8.K4]  
break; 1:f9J  
} L1Iz<>  
} }>
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if(breakWhile) E#ul IgD  
break; }Ub6eXf(2  
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9hOJvQ2U]  
//count++; %we u 1f  
//if(count>4) +eFFSt  
// siteStop(); y5do1Z  
} <
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System.err.println("文件下载结束！"); iy14mh\ ~  
} UG'9*(*  
catch(Exception e){e.printStackTrace ();} XVvK2(  
} WXmn1^"kK}  
~:3QBMk::  
HA2k[F@3^  
//获得文件长度 ,]+z)   
public long getFileSize() \hM|(*DL  
{ Bc6|n :;u  
int nFileLength = -1; q.2ykL  
try{ ; =X P&  
URL url = new URL(siteInfoBean.getSSiteURL()); K)\M5id]  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); $aN&nhoO<  
httpConnection.setRequestProperty("User-Agent","NetFox"); 21< j\ M  
5lm<%  
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int responseCode=httpConnection.getResponseCode(); c2e tc8  
if(responseCode>=400) ?zQA
  
{ K9OY
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processErrorCode(responseCode); xv&Q+HD  
return -2; //-2 represent access is error q
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} V\^EfQ  
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String sHeader; Qt/8r*Oe  
Z| V`B `  
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for(int i=1;;i++) z&{5;A}Q@  
{ p\JfFfC  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); /k<WNZM  
//Utility.log(in.readLine()); C\di7z:  
sHeader=httpConnection.getHeaderFieldKey(i); !kE-_dY6)  
if(sHeader!=null) ;ByOth|9P  
{ e(I=^#u6  
if(sHeader.equals("Content-Length")) hrhb!0  
{ Xt#4/>dlR  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); DXa-rk8  
break; ~R&;v3  
} #_(jS+lP?k  
} t| 'N+-T3  
else `$B3X  
break; {WPobP"  
} Qbyv{/  
} R8T]2?Q1  
catch(IOException e){e.printStackTrace ();} '*k'i;2/1  
catch(Exception e){e.printStackTrace ();} !X<~-G2)l  
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Utility.log(nFileLength); Hv\-_>}K  
7?kIVP1r  
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return nFileLength; o4zM)\;F  
} H)>;/#!r-  
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//保存下载信息（文件指针位置） .?!N^_ Ez3  
private void write_nPos() V`7FKL@"  
{ ^pe{b9c  
try{  R#DwF,  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 5GPo*Qpl  
output.writeInt(nStartPos.length); 8G5m{XTS(  
for(int i=0;i<nStartPos.length;i++) hDp6YV,q  
{ ^4`Px/&  
// output.writeLong(nPos); =@8H"&y`
 
output.writeLong(fileSplitterFetch.nStartPos); * C6a?]  
output.writeLong(fileSplitterFetch.nEndPos); i![dPM  
} sSQs#+&=[  
output.close(); r,Nq7Txn?  
} A%{W{UP8N  
catch(IOException e){e.printStackTrace ();} LJ(1RK GCz  
catch(Exception e){e.printStackTrace ();} n Ml%'[u  
} mK [0L  
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//读取保存的下载信息（文件指针位置） i6 (a@KRY  
private void read_nPos() ZU9c 5/J  
{ A6pj
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try{ y:vxE8$Q  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); DANw1_X\  
int nCount = input.readInt(); P b]3&!a  
nStartPos = new long[nCount]; 4)<~4 '  
nEndPos = new long[nCount]; (Gw,2-A  
for(int i=0;i<nStartPos.length;i++) }Iz7l{al  
{ x"CZ]p&m  
nStartPos = input.readLong(); o)[2@fRC(  
nEndPos = input.readLong(); \C`~S7jC  
} ?&^?-S% p  
input.close(); a /:@"&Y  
} bgK<pi)d  
catch(IOException e){e.printStackTrace ();} pOrWg@<\L  
catch(Exception e){e.printStackTrace ();} Xe^
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} z8J."27ND  
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private void processErrorCode(int nErrorCode) )5.C]4jol  
{ L:k9#6  
System.err.println("Error Code : " + nErrorCode); ph#tgLJ  
} @j4U^"_QB  
Eb=#9f%y>&  
jh.@-  
//停止文件下载 kee|42E  
public void siteStop() k~|-gfFP  
{ D K
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bStop = true; (}
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for(int i=0;i<nStartPos.length;i++) h#hxOVl%x  
fileSplitterFetch.splitterStop(); 2*w:tT8+X  
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} &k1T08C*  
} R3!@?mcr  
//负责部分文件的抓取 Cua%1]"4w  
**FileSplitterFetch.java 1 `7<2w  
*/ E3*\ ^Q_  
package NetFox; ,~);EC=`  
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2]c{P\  
import java.io.*; ee/&/Gt  
import java.net.*; c.A|Ir  
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public class FileSplitterFetch extends Thread { 7 uarh!  
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String sURL; //File URL D>!6,m2  
long nStartPos; //File Snippet Start Position n3`&zY  
long nEndPos; //File Snippet End Position SgEBh  
int nThreadID; //Thread's ID tL+OCLF;  
boolean bDownOver = false; //Downing is over `+/H
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boolean bStop = false; //Stop identical wO>L#"X^v  
FileAccessI fileAccessI = null; //File Access interface !P$'#5mr  
(?*BB3b`  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 3s>'hn  
{ "z*:'8;E  
this.sURL = sURL; ?~QIALA  
this.nStartPos = nStart; 4\&  
this.nEndPos = nEnd; x5Z-{"  
nThreadID = id; EOoZoVdzx  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 O`$#Pg  
} 34QfgMyH  
}elH75[64  
tyDY'W\]  
public void run() yt+}K)Hz  
{ 7DfTfTU6  
while(nStartPos < nEndPos && !bStop) "W#t;;9Wz  
{ pfd#N[c  
)){xlFA}  
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try{ |Cdvfk  
URL url = new URL(sURL); Kwhdu<6  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); XIWm>IQ[)  
httpConnection.setRequestProperty("User-Agent","NetFox"); o."rxd  
String sProperty = "bytes="+nStartPos+"-"; Sc]P<F7N]  
httpConnection.setRequestProperty("RANGE",sProperty); a0*2) uL}  
Utility.log(sProperty); 8:.nEo'  
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InputStream input = httpConnection.getInputStream(); 4{qB X?  
//logResponseHead(httpConnection); i\H+X   
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byte[] b = new byte[1024]; =_[Z W  
int nRead; vSW L$Y2  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) [ "xn5lE  
{ X[W]=yJJ  
nStartPos += fileAccessI.write(b,0,nRead); ]=!P
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//if(nThreadID == 1) I@l>w._.  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); D0;tcm.$  
} !?[oIQ)h  
'ho{eR@d  
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Utility.log("Thread " + nThreadID + " is over!"); @S 6u9v  
bDownOver = true; D^Ys)- d  
//nPos = fileAccessI.write (b,0,nRead); 0 3~Ikll  
} r Db>&s3  
catch(Exception e){e.printStackTrace ();} o/
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} t?^9HP1b_  
} M_``'gw  
{?{U,&  
2BzqY`O  
//打印回应的头信息 $cVi;2$p  
public void logResponseHead(HttpURLConnection con) @1R8-aa-r  
{ w.N,)]h  
for(int i=1;;i++)  0v^:  
{ T[Pa/j{  
String header=con.getHeaderFieldKey(i); s{/qS3=  
if(header!=null) \Z/k;=Sla  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ZB5?!.ND  
Utility.log(header+" : "+con.getHeaderField(header)); =ex'22  
else 5A&y]5-Q`  
break; V8O.3fo`[`  
} &!35/:~uD  
} Ih1|LR/c  
*T4<&  
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public void splitterStop() '9J|=z9.  
{ Napf"Av  
bStop = true; 2@vj!U8  
} W>spz~w%j  
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} v&3O&y/1v  
}iIbc
A  
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/* J<JBdk  
**FileAccess.java )'q%2%Ak  
*//文件访问(定位，写) /'y5SlE[J  
package NetFox; v@G4G*x\  
import java.io.*; | W#~F&{]  
OYf{?-QD  
,2WH/"  
public class FileAccessI implements Serializable{ m%QqmTH  
|ia@,*KD  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节
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RandomAccessFile oSavedFile; GoE#Mxhxo  
long nPos; Su8'$CFz$.  
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public FileAccessI() throws IOException 9u wL{P&  
{ ] mj v;C  
this("",0); )u@t.)ChAV  
} b"8FlZ$  
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public FileAccessI(String sName,long nPos) throws IOException R9.HD?H@  
{ U 5`y  
oSavedFile = new RandomAccessFile(sName,"rw"); @~jxG%y86  
this.nPos = nPos; ~uPk  
oSavedFile.seek(nPos); >zL|8f  
} ~Sy-gaJ  
I{dl%z73  
i=QqB0  
public synchronized int write(byte[] b,int nStart,int nLen) +Z?[M1g  
{ q|q::q*  
int n = -1; [Hcaw   
try{ eX<K5K.B  
oSavedFile.write(b,nStart,nLen); $ u2Cd4  
n = nLen; _1JmjIH)M  
} Wp*sPZ  
catch(IOException e) ) YSh D  
{ 5_G'68;OV  
e.printStackTrace (); L? ;/cO^  
} ,0T)Oc|HL/  
- 8syjKTg  
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return n; ^now}u9S6  
} NyJnO
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} *1;23BiH-  
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/* |t\KsW  
**SiteInfoBean.java ci7~KewJ*  
*/ U5rxt^  
package NetFox; 0]a15  
u~71l)LA  
'P/taEi=R  
public class SiteInfoBean { [&n|\!  
;4d.)-<No_  
*IlQ5+3I  
private String sSiteURL; //Site's URL e<'U8|}hc{  
private String sFilePath; //Saved File's Path *?Wtj  
private String sFileName; //Saved File's Name
}'j
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private int nSplitter; //Count of Splited Downloading File Kcn\g.  
 EW5]!%  
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public SiteInfoBean() J%4HNW*p  
{//nSplitter的缺省值为5 70<K.T<b  
//default value of nSplitter is 5 /s-d?  
this("","","",5); /:6Q.onmLn  
} zZYH
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-ddOh<U>  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ew"m!F#  
{ B_@7IbB  
sSiteURL= sURL; 6ZHv,e`?  
sFilePath = sPath; )
b (X  
sFileName = sName; kt<@H11  
this.nSplitter = nSpiltter; #! @m y  
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,$i<@2/=m  
} Qrz*Lvle h  
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public String getSSiteURL() | W?[,|e  
{ i-V0Lm/  
return sSiteURL; -t b;igv  
} tD^a5qPh  
^HoJ.oC/  
5|m9:Hv[#  
public void setSSiteURL(String value) J]]\&MtaO  
{ ,A?v,Fs>O[  
sSiteURL = value; >;.*  
} <|dj^.^  
C!kbZTO[p"  
]h!*T{
:  
public String getSFilePath() ~6fRS2u  
{ eb7UoZw  
return sFilePath; DsG !S*  
} Vdy\4 nu(  

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I,z"_[^G  
public void setSFilePath(String value) a5I%RY  
{ kpY%&  
sFilePath = value; 5z[6rT=a  
} 7\ZL  
.n=xbx:=  
tJG (*  
public String getSFileName() hf[IEK  
{ "#J}A0  
return sFileName; SOYDp;j  
} Vg) ^|  
6<Be#Y]b  
h?3f5G*&H  
public void setSFileName(String value) t.u{.P\Md\  
{ T)O]:v  
sFileName = value; 9Iy[E,j  
} X~#@rg!"  
`;T?9n  
_BCT.ual  
public int getNSplitter() *ig5Q(b*N  
{ ur`V{9g  
return nSplitter; 0Mq6yu^  
} hAYQ6
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&,Uc>L%m  
6vZt43"m?\  
public void setNSplitter(int nCount) IBF.&[[S  
{ $&NbLjeS  
nSplitter = nCount; [y$j9  
} =1_jaDp  
} gFgcxe6  
H.f9d.<W%  
g')?J<z  
/* 8Y]u:v  
**Utility.java mURX I'JkX  
*/ OHQ3+WJ  
package NetFox; ~'|&{-<  
bwT"$Ee  
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public class Utility { jeyaT^F(   
) +*@AME  
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public Utility() KS8\F0q  
{ _GRv  
7?*~oV
ZW  
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} r]xdhR5  
s'_$j$1  
//线程睡眠 "F04c|oR<X  
public static void sleep(int nSecond) FUH*]U  
{ Pm'.,?"  
try{ $d
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Thread.sleep(nSecond); ]q@rGD85K  
} 7?)m(CFy  
catch(Exception e) )bF)RLZ  
{ if\k[O 1T6  
e.printStackTrace (); &Qz"nCvJ  
} ^D0/H N   
} /o~ @VF:  
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//日志 >f3k3XWRT  
public static void log(String sMsg) t,UW&iLK  
{ cC*zj\O  
System.err.println(sMsg); \0xzBs1!  
} %Td+J`|U+  
oo"JMD)  
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public static void log(int sMsg) kemr@_  
{ H7 o$O  
System.err.println(sMsg); `=WzG"  
} ^2P;CAjj-  
} Yf%[6Y{  
2-/YYe;C  
}d$vcEI$3  
/* Q
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**TestMethod.java a2IV!0x  
*/ L|vaTidc0  
package NetFox; Bx_8@+  
1WZKQeOo  
fte!Ll'  
public class TestMethod { \L&qfMjW"Z  
ZfF`kD\  
=t <:zLe  
public TestMethod() \q>e1-  
{ ///xx/weblogic60b2_win.exe 4c9-[KKCV  
try{ l93
Q"*_  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); .XZ 71E  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 9e|{z9z[l  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 7zi^{]  
fileFetch.start(); s7X~OF(#  
} K[Ws/yc^a  
catch(Exception e){e.printStackTrace ();} oc,U4+T  
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JRcuw'8+q  
} Fb$5&~d  
?.|wfBI  
:$u{  
public static void main(String[] args) F\YcSDM  
{ cPa 0n4  
new TestMethod(); ACMpm~C8Gu  
} 8O}A/*1FJ  
} &)/H?S;yN  
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