http断点续传简单实现（java)

/* +n7?S~R$  
**SiteFileFetch.java XfKo A0  
*/ 5bA)j!#)|X  
package NetFox; TO-nD>  
import java.io.*; ,:%"-`a%  
import java.net.*; ) /v6l  
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public class SiteFileFetch extends Thread { qVdwfT{1J  
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SiteInfoBean siteInfoBean = null; //文件信息Bean fd#jY}  
long[] nStartPos; //开始位置 e4G4GZH8  
long[] nEndPos; //结束位置 '*Almv{  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Q43|U4a  
long nFileLength; //文件长度 E7Ulnvd  
boolean bFirst = true; //是否第一次取文件 4]/7 )x?R  
boolean bStop = false; //停止标志 p2N:;lXM  
File tmpFile; //文件下载的临时信息 Ed:eGm }  
DataOutputStream output; //输出到文件的输出流 0x9x@gF  
?\#N9+{W  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） <BW[1h1k5_  
public SiteFileFetch(SiteInfoBean bean) throws IOException ncSFj.}w]  
{ k2xHH$+{#=  
siteInfoBean = bean; 7y`}PMn  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 9<vWcq*4  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); (4@lKKiU%H  
if(tmpFile.exists ()) 5o/&T"]@  
{ 1pCieTz!PN  
bFirst = false; fl;s9:<  
read_nPos(); jA(>sz  
} kvh&d|  
else .c#y%S  
{ )~V4+*<  
nStartPos = new long[bean.getNSplitter()]; X{^}\,cVtG  
nEndPos = new long[bean.getNSplitter()]; TyKWy0x-3  
} 720)VzT  
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} 0I{
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public void run() nkv(~ej(  
{ @vMA=v7a  
//获得文件长度 QaGlR`Y  
//分割文件 9 C{;h  
//实例FileSplitterFetch 8_&CT :u>  
//启动FileSplitterFetch线程 
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//等待子线程返回 BI:k
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try{ n9;;x%6.I  
if(bFirst) 9=,uq;  
{ huudBc A[  
nFileLength = getFileSize(); 5`]UE7gT  
if(nFileLength == -1) [DHoGy,P  
{ p7ir*r/2  
System.err.println("File Length is not known!"); K
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} 4 V1bLm  
else if(nFileLength == -2) ,+;:3gRk9  
{ {u[V{XIUh  
System.err.println("File is not access!");
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} !vn1v)6  
else ^VT1vu %03  
{ efG6v  
for(int i=0;i<nStartPos.length;i++) "C?5f]T  
{
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); ?%O3Oi Xz  
} 9e U[*S  
for(int i=0;i<nEndPos.length-1;i++) _al|'obomy  
{ =&dW(uyzY  
nEndPos = nStartPos[i+1]; 7DKz;o  
} Kd3?I5t  
nEndPos[nEndPos.length-1] = nFileLength; iU+nqY'  
} aS}1Q?cU  
} &t(0E:^TRU  
N4K8 u'f^  
^+SkCO  
//启动子线程 IkzTJ%>  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; OquAql:   
for(int i=0;i<nStartPos.length;i++) =N);v\ Q$!  
{ O9(r{Vu7u  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), jxgj,h"}9`  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), GFk1
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nStartPos,nEndPos,i); zciCcrJ  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); K1?Gmue#I  
fileSplitterFetch.start(); -S%x wJKM  
} <P%}|@  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), '<
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); pbHsR^  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", to"'By{9  
nEndPos = " + nFileLength); P%Ay3cR+E  
// fileSplitterFetch[nPos.length-1].start(); 7{oe ->r  
YYg)  
3E^M?N2oc  
//等待子线程结束 T88Y qI  
//int count = 0; x\s,= n3z  
//是否结束while循环 mgZf3?,)  
boolean breakWhile = false; @OV-KT[>  
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while(!bStop) /cFzotr"9  
{ Fk=}iB#(  
write_nPos(); Hqz?E@bc@  
Utility.sleep(500); O)R(==P26P  
breakWhile = true; rC[6lIP  
02AI%OOH  
 6qo^2  
for(int i=0;i<nStartPos.length;i++) >cL{Ya}Rz  
{ uk`8X`'  
if(!fileSplitterFetch.bDownOver) qIwV q!=  
{ iF+RnWX\  
breakWhile = false; p3^jGj@  
break; "()sb?&  
} }i!pL(8;  
} nL]^$J$  
if(breakWhile) P5QQpY{<I  
break;  1;eX&  
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IO.<q,pP!_  
//count++; o**yZ2  
//if(count>4) Wx)K*9  
// siteStop(); 4YU/uQm  
} _DPOyR2  
Fr
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System.err.println("文件下载结束！"); {Z{o"56f  
} '_+9y5  
catch(Exception e){e.printStackTrace ();} (3,.3)%`  
} &B{8uge1
 
|-2}j2'  
+$z]w(lbT  
//获得文件长度 t@bt6J .{  
public long getFileSize() !$XHQLqF2  
{ ZC^C  
int nFileLength = -1; '3l$al:H^  
try{ 3mt%!}S  
URL url = new URL(siteInfoBean.getSSiteURL()); 6\dX
 
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); )E7 FA|  
httpConnection.setRequestProperty("User-Agent","NetFox"); T9y;OG  
zjX7C~h^Q  
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int responseCode=httpConnection.getResponseCode(); ~KIDv;HSb[  
if(responseCode>=400) jkrx]`A{~  
{ zxZtz  
processErrorCode(responseCode); zz$q5[n  
return -2; //-2 represent access is error Xwu.AVsr  
} {6vEEU  
|@VF.)_  
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String sHeader; }3/~x  
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*ftC_v@p5  
for(int i=1;;i++) ]Nk!4"  
{ {gy+3  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); q{4|Kpx@  
//Utility.log(in.readLine()); (hZ:X)E>  
sHeader=httpConnection.getHeaderFieldKey(i); +`| *s3M  
if(sHeader!=null) f!GHEhQ9  
{ F#q&(  
if(sHeader.equals("Content-Length")) Db03Nk>#  
{ zDBD.5R;  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); :pKG\A  
break; - HOnB=  
} Mn^zYW|(  
} f$xhb3Qn  
else d;suACW  
break; 0my9l;X   
} ML!
9:vz  
} H"YL k  
catch(IOException e){e.printStackTrace ();} M[
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catch(Exception e){e.printStackTrace ();} <4?*$  
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~  
Utility.log(nFileLength); Uxl(96  
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return nFileLength; b6W#SpCF  
} {K.rl%_|N  
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H*U`  
//保存下载信息（文件指针位置） ]O{_O&w  
private void write_nPos() NtZ6$o<Y  
{ hH4o;0rqJ  
try{ Sni=gZK  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 6mG3fMih.  
output.writeInt(nStartPos.length); 71iRG*O  
for(int i=0;i<nStartPos.length;i++) $AwZ2HY  
{ 03E3cp"  
// output.writeLong(nPos); C!UEXj`l9  
output.writeLong(fileSplitterFetch.nStartPos); _-a|VTM  
output.writeLong(fileSplitterFetch.nEndPos); QPg2Y<2  
} C6k4g75U2  
output.close(); ?n*fy  
} i!~>\r\6\  
catch(IOException e){e.printStackTrace ();} lCFU1 GHH  
catch(Exception e){e.printStackTrace ();} _nX%#/{  
} .ewZV9P)t  
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%-^}45](q  
//读取保存的下载信息（文件指针位置） *wUdC  
private void read_nPos() @l,{x|00  
{ _g6wQdxT  
try{ |zMqJ.qu  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); jU$Y>S>l  
int nCount = input.readInt(); 0BC`iql5  
nStartPos = new long[nCount]; zzf7S%1I  
nEndPos = new long[nCount]; NWISS  
for(int i=0;i<nStartPos.length;i++) [ -12]3  
{ 9s $PrF  
nStartPos = input.readLong(); i[=C_+2  
nEndPos = input.readLong(); .~<]HAwq  
} u5E/m  
input.close(); XtW_  
} 4I ,o&TK  
catch(IOException e){e.printStackTrace ();} A+2oh3  
catch(Exception e){e.printStackTrace ();} qc-C>Ra  
} 6UB6;-  
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private void processErrorCode(int nErrorCode) QN #)F  
{ q!2<=:f  
System.err.println("Error Code : " + nErrorCode); ;Uk!jQh  
} u%aFb*  
E4m:1=Nd~]  
%MNk4UsV  
//停止文件下载 ~^7  
public void siteStop() "`]'ZIx[R/  
{ PN9^[X  
bStop = true; <UK5eVQn  
for(int i=0;i<nStartPos.length;i++) Ld~4nc$H8  
fileSplitterFetch.splitterStop(); 0Q3YN(  
?H0m<jO8~  
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} 8_awMVAy  
} ~h|m&XK+Q  
//负责部分文件的抓取 5ZUy:  
**FileSplitterFetch.java 65"uD7;  
*/ J" wKRy  
package NetFox; {e6KJ@H6  
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import java.io.*; dqwWfn1lt  
import java.net.*; iE+6UK  
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public class FileSplitterFetch extends Thread { (olLB  
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String sURL; //File URL 7uA\&/ ,  
long nStartPos; //File Snippet Start Position '{W3j^m7  
long nEndPos; //File Snippet End Position M/)B" q  
int nThreadID; //Thread's ID *s36OF!  
boolean bDownOver = false; //Downing is over 1O9$W?)Q  
boolean bStop = false; //Stop identical ,#Ln/;  
FileAccessI fileAccessI = null; //File Access interface j #es2;  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 1!s!wQgS  
{ &$Ci}{{n
#  
this.sURL = sURL; -PXoMZx%  
this.nStartPos = nStart; .SBc5KX  
this.nEndPos = nEnd; jRwa0Px(  
nThreadID = id; m/" J s  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 \3: L Nt  
} ?GfxBZ
WJ  
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public void run() {)uU6z {'  
{ @oA0{&G{  
while(nStartPos < nEndPos && !bStop) #\0TxG5'QA  
{ d{l{P]nr  
-UTV:^  
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try{ k)Zn>  
URL url = new URL(sURL); ac3_L$X[  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); g X8**g'  
httpConnection.setRequestProperty("User-Agent","NetFox"); m/KjJ"s,
 
String sProperty = "bytes="+nStartPos+"-"; @%%bRY  
httpConnection.setRequestProperty("RANGE",sProperty); e+x*psQ  
Utility.log(sProperty); oB3q AP  
{[N?+ZJD*L  
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InputStream input = httpConnection.getInputStream();
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//logResponseHead(httpConnection); e-jw^   
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byte[] b = new byte[1024]; n'Bmz  
int nRead; :`;(p{  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) gDMAc/V`l  
{ %db3f z  
nStartPos += fileAccessI.write(b,0,nRead); <qr^Nyo4  
//if(nThreadID == 1) Qz# 3p3N?  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); s?5d  
} nc-Qz  
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Utility.log("Thread " + nThreadID + " is over!"); q'by
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bDownOver = true; ([1=>Jw"  
//nPos = fileAccessI.write (b,0,nRead); V15q01bE#  
} # UjEY9"M  
catch(Exception e){e.printStackTrace ();} .byc;9M%  
} ~U/8 @gR  
} va@XbUC  
?${V{=)*X'  
3L*+8a  
//打印回应的头信息 x{~_/;\p3  
public void logResponseHead(HttpURLConnection con) e{:86C!d)  
{ '}@e5^oL  
for(int i=1;;i++)  &Q<EfB  
{ AVU7WU{  
String header=con.getHeaderFieldKey(i); $m{{,&}k  
if(header!=null) OX`?<@6  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); X1O65DMr`g  
Utility.log(header+" : "+con.getHeaderField(header)); wXP_]-  
else /#@LRN<oCq  
break; o}d2N/T  
} PVZEB  
} QXsfp  
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public void splitterStop() j-j'phK  
{ RFhU#  
bStop = true; gYRq
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} MPqY?KF  
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} LH bZjZ2  
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/* )iT.A  
**FileAccess.java )~1.<((<  
*//文件访问(定位，写) nR(#F9  
package NetFox; mi*:S%;h  
import java.io.*; XSD"/_xD  
FpwlV}:  
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public class FileAccessI implements Serializable{ Rd`{qW  
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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 Dm&lSWW`/  
RandomAccessFile oSavedFile; e6Wl7&@6  
long nPos; b(g_.1[  
Ar\IZ_Q  
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public FileAccessI() throws IOException U+:S7z@j?  
{ u!hq
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this("",0); Bidqf7v  
} 6(\q< fx  
q]2}UuM|U  
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public FileAccessI(String sName,long nPos) throws IOException ['Hp?Q|k  
{ Ej-=y2j{g  
oSavedFile = new RandomAccessFile(sName,"rw"); ;JMOsn}
8  
this.nPos = nPos; /%2:+w  
oSavedFile.seek(nPos); \Sz4Gr0g3Z  
} \Mobq  
---Ks0\V  
dw|-=~  
public synchronized int write(byte[] b,int nStart,int nLen) U@1#!ZZ6  
{ qpluk!  
int n = -1; Lr!L}
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try{ s?4%<jz  
oSavedFile.write(b,nStart,nLen); de3yP,  
n = nLen; J
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} s@*,r@<  
catch(IOException e) X; e`y:9  
{ CUAg{]  
e.printStackTrace (); KfJ c  
} 7vB9K_wCI  
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return n; :< KSf#O  
} p{\qSPK  
]w1BJZa36  
n_e}
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} u*#-7   
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/* *y":@T  
**SiteInfoBean.java %[+a[/  
*/ 4GmSG,]  
package NetFox; wN/*|?`Z  
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public class SiteInfoBean { p*(U*8Q  
M ,.0[+  
)'/nS$\E:  
private String sSiteURL; //Site's URL j\jL[hG_  
private String sFilePath; //Saved File's Path s[vPH8qb  
private String sFileName; //Saved File's Name vTe$77n
 
private int nSplitter; //Count of Splited Downloading File >*<6 zQf  
+73=2.C0  
i9f7=-[U_  
public SiteInfoBean() Q]2sj:  
{//nSplitter的缺省值为5 UH1S_:6  
//default value of nSplitter is 5 &deZ  
this("","","",5); U{U:8==  
} gKm@B{rC  
YiY&;)w  
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+  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) JsWq._O{/  
{ W>t&N  
sSiteURL= sURL; 1DI"LIL  
sFilePath = sPath; R9|2&pfm(M  
sFileName = sName; 3
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this.nSplitter = nSpiltter; 3<~2"@J  
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3& fIO  
} /z.7:<gZ(  
{8*d;[X50  
[EW$7 se~  
public String getSSiteURL() )$Dcrrj  
{ N c&i) qh  
return sSiteURL; y.ivz  
} &?5{z
\;1"  
6S&

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9wDBC~.  
public void setSSiteURL(String value) u]>>B>KOJ7  
{
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sSiteURL = value; 67KRM(S  
} b[&,%Sm+6  
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&ttv4BC^r  
public String getSFilePath() _L `N^I.  
{ [Q.4]K2  
return sFilePath; a|6x!p2X  
} "JQt#[9l
 
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public void setSFilePath(String value) 4,*^QK  
{ bN7UO  
sFilePath = value; aJa^~*N/Aa  
} bCaPJ!ZO  
Jv4D^>yj[  
:+%h  
public String getSFileName() 5shu76  
{ 33,JUQ2u  
return sFileName; 9,EaN{GM  
} _w5~/PbWt  
Ph
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*
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public void setSFileName(String value) ek;&<Z_ ]  
{ N|Cy!E=d  
sFileName = value; #@\NdW\  
} rO?x/{;ai  
$bi_i|?  
+GPT:\*q6  
public int getNSplitter()
,;=( )-  
{ :hhE=A>X  
return nSplitter; jcv1z v.  
} BtNW5'^  
v<J;S9u=  

1uS>{M  
public void setNSplitter(int nCount) b]g&rwXYt  
{ t+4Y3*WeGF  
nSplitter = nCount; (HrkUkw  
} N5rG.6K  
} i\Q"a B"r  
|n6Q  
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/* u0oYb_Yv  
**Utility.java 6nWx>R<  
*/ :rs\ydDUF  
package NetFox; `j!2uRFe>  
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public class Utility { 6 XOu~+7  
9M7(_E;)B  
t{S{!SF4  
public Utility() $Z%aGc*  
{ M}oFn}-T9a  
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X,Q=n2X?3  
} 
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`7qp\vYL  
//线程睡眠 ;Y|~!%2~  
public static void sleep(int nSecond) SX=0f^  
{ \Af|$9boHz  
try{ CpqSn/
 
Thread.sleep(nSecond); v.LUK  
} .kKwdqO+zB  
catch(Exception e) -^jLU FC  
{ zI:5I@ X  
e.printStackTrace (); Gxa.<E^k  
} &P{p\v2Y  
} \;:@=9`  
73z|'
0.  
//日志 6p=xgk-q  
public static void log(String sMsg) ?! _pP|  
{ .f<VmUca  
System.err.println(sMsg); 8~Hs3\Hp  
} +ZA\M:^b  
Q.2nUT`  
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public static void log(int sMsg) 07"Oj9NlA  
{ W]}V<S$  
System.err.println(sMsg); ;ld~21#m  
} 2[&-y[1  
} $~@096`QL<  
PW//8
lsR  
iN4'jD^oP  
/* Qp{-!*  
**TestMethod.java 6ym)F!t8l  
*/ |wb(rua  
package NetFox; hG;=ci3EE  
y'O{8Q8T  
Cl.T'A$  
public class TestMethod { j"sO<Q{6%  
J'c9577$  
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public TestMethod()

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{ ///xx/weblogic60b2_win.exe ^r :A^q  
try{ w:zC/5x`  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Y <k,E  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); UYrzsUjg&  
SiteFileFetch fileFetch = new SiteFileFetch(bean); yi;t  
fileFetch.start(); &FF. Ddt{  
} ?[B[ F  
catch(Exception e){e.printStackTrace ();} 2\tj
eg  
htrj3$q(4  
6SO7iFS  
} 6%INNIyAWa  
;L%~c4`l~m  
;OJ0}\*iP8  
public static void main(String[] args) swq!Sp  
{ fToI,FA
 
new TestMethod(); 5t?2B]  
} "[S 6w  
} gbf=H8]  
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