http断点续传简单实现（java)

/* Z{BK@Q4z  
**SiteFileFetch.java |'1.ajxw  
*/ ,*U-o}{8C?  
package NetFox; Y
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import java.io.*; %hN>o)  
import java.net.*; \1gAWUt('  
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public class SiteFileFetch extends Thread { K<:%ofB"S  
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|f @A-d X  
SiteInfoBean siteInfoBean = null; //文件信息Bean LwRzzgt  
long[] nStartPos; //开始位置 }=)u_q  
long[] nEndPos; //结束位置 8^+|I,  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 G-2~$ u  
long nFileLength; //文件长度 ;
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boolean bFirst = true; //是否第一次取文件 iB(?}SaAZ  
boolean bStop = false; //停止标志 j@(S7=^C6%  
File tmpFile; //文件下载的临时信息 v~Dobk/n  
DataOutputStream output; //输出到文件的输出流 Ar~/KRK  
:AFW=e@<  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） EBW*v '  
public SiteFileFetch(SiteInfoBean bean) throws IOException "lu^  
{ ]:D&kTc  
siteInfoBean = bean; C(v'7H{4cW  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 6Aqv*<1=62  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Qc-W2%  
if(tmpFile.exists ()) 9)]`le  
{ Y\_mqd  
bFirst = false; S+[,\>pY  
read_nPos(); M !"Q7>d  
} XchD3p+uB  
else hfLe<,  
{ `Zo5!"'  
nStartPos = new long[bean.getNSplitter()]; /<LjD  
nEndPos = new long[bean.getNSplitter()]; &$CyT6mb^  
} aC1 xt(  
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} |tI{MztJ"c  
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public void run() ;:[P/eg  
{ T<7}IH$6xE  
//获得文件长度 4IfkYM  
//分割文件 /rD9)
 
//实例FileSplitterFetch OI)k0t^;D  
//启动FileSplitterFetch线程 `O3#/1+  
//等待子线程返回 sOWP0xY  
try{ !lEV^SQJs  
if(bFirst) b4$.uLY  
{ v8E:64  
nFileLength = getFileSize(); ]A-LgDsS  
if(nFileLength == -1) 4xs>X7  
{ UVi9}zr  
System.err.println("File Length is not known!"); u_ :gqvC=  
} e'npa*.e  
else if(nFileLength == -2) 8[^b8^  
{ T[},6I|!  
System.err.println("File is not access!"); ZyC[w7$I2  
} O>X!78]#K  
else d<\
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{ x51p'bNy  
for(int i=0;i<nStartPos.length;i++) ^JIs:\g<<  
{ }FV_jJ  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); @&G %cW(  
} S,+|A)\#  
for(int i=0;i<nEndPos.length-1;i++) \3U.;}0_X  
{ kbz+6LcV  
nEndPos = nStartPos[i+1]; y>UQm|o<W  
} %tkL<e  
nEndPos[nEndPos.length-1] = nFileLength; uZ1G,9  
} p_g8d&]V  
} fk5pPm|MiL  
`$;%%/tx  
G\f:H%[5[  
//启动子线程 M|z4Dy  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; +>mU4Fwp  
for(int i=0;i<nStartPos.length;i++) a!x?Apww  
{ kafj?F  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), [DSzhi]  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), W6*5e{  
nStartPos,nEndPos,i); ",E$}= ,Z  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ^j_t{h)W(0  
fileSplitterFetch.start(); /LCRi  
} MIAC'_<-e  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), )!`>Q|]}Zd  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); /Q9iO&Vu  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", G`jJKiC  
nEndPos = " + nFileLength); [*=UH*:'N  
// fileSplitterFetch[nPos.length-1].start(); c$%I^f}'  
9;pD0h|  
%Zu+=IZ  
//等待子线程结束 'F8:|g  
//int count = 0; za4:Jdr  
//是否结束while循环 6$$ku  
boolean breakWhile = false; <m?/yREK2  
r?n3v[B  
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while(!bStop) s\1c.  
{ ivl
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write_nPos(); `>}e 5  
Utility.sleep(500); Nj4^G ~_  
breakWhile = true; 5l(NX  
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for(int i=0;i<nStartPos.length;i++) >9]i#So^  
{ 4^BHJOvs  
if(!fileSplitterFetch.bDownOver) +D+Rf,D  
{ SE!0f&  
breakWhile = false; `zRm
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break; {f)"F;]V  
} y 4jelg  
} 0j|JyS:}G  
if(breakWhile) ?qjlWCV|e  
break; DWRq \`P  
gkDlh{  
0V:PRq;v0  
//count++; L9)
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//if(count>4) u~^d5["T  
// siteStop(); 09u@
-  
} |d8x55dk  
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System.err.println("文件下载结束！"); | sio:QP  
} ep2#a#&'  
catch(Exception e){e.printStackTrace ();} uCNi&
.  
} T"$yh2tSY  
<U() *0  
ta 66AEc9  
//获得文件长度 hzjEO2  
public long getFileSize() Lk|%2XGO&  
{ <);Nc1  
int nFileLength = -1; x:)8+Rn}  
try{ *^&2L,w  
URL url = new URL(siteInfoBean.getSSiteURL()); ,2YkQ/>  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ^/kn#1H7&  
httpConnection.setRequestProperty("User-Agent","NetFox"); B@W`AD1^{  
)!&7XL[  
pkL&j<{  
int responseCode=httpConnection.getResponseCode(); IPhV|7
 
if(responseCode>=400) hs"=>(P)  
{ *h>KeIB;  
processErrorCode(responseCode); }QL 2#R  
return -2; //-2 represent access is error }t[?g)"M#-  
} }G#TYF}  
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String sHeader; 1 f;k)x  
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for(int i=1;;i++) =hO0@w  
{ B9RB/vHH  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); =;9*gDfD  
//Utility.log(in.readLine()); KU> $=Rd  
sHeader=httpConnection.getHeaderFieldKey(i); f@%H"8w!  
if(sHeader!=null) E K)7g~  
{ jQp7TdvLE$  
if(sHeader.equals("Content-Length")) jcWv&u|  
{ D,rF?t>=S  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ^f-?xXPx  
break; u2SnL$A7  
} ,3t('S
E  
} hDp -,ag{  
else \)=X=yn2  
break; El~x$X*  
} q89#Ftkt  
} <wt#m`Za  
catch(IOException e){e.printStackTrace ();} xbFoXYqgP  
catch(Exception e){e.printStackTrace ();} ]}_@!F)  
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Utility.log(nFileLength); P~V0<$C  
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return nFileLength; 30(O]@f~  
} 5TqT`XTz
m  
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jh  
//保存下载信息（文件指针位置） ]wg+zOJu]+  
private void write_nPos() l I&%^>  
{ Ds4n>V,o  
try{ :xitV]1.   
output = new DataOutputStream(new FileOutputStream(tmpFile)); 6% @@~"  
output.writeInt(nStartPos.length); qm
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for(int i=0;i<nStartPos.length;i++) ;Ocih<4k  
{ TbqED\5@9w  
// output.writeLong(nPos); 8}3dwr;-  
output.writeLong(fileSplitterFetch.nStartPos); j$h.V#1z  
output.writeLong(fileSplitterFetch.nEndPos); / vI sX3v  
} ?\dY!  
output.close(); +'9l 2DI;  
} HhN;&67~Z  
catch(IOException e){e.printStackTrace ();} | I_,;c  
catch(Exception e){e.printStackTrace ();} =.9L/74@  
} `+[e]dH  
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//读取保存的下载信息（文件指针位置） {=WTAgP  
private void read_nPos() ^EGe%Fq*x]  
{ fcd
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try{ 7mipj]
 
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 0z@KkU{Z  
int nCount = input.readInt(); {VBx;A3*I  
nStartPos = new long[nCount]; 1b:3'E.#w  
nEndPos = new long[nCount]; eMk?#&a)  
for(int i=0;i<nStartPos.length;i++) Fp>iwdjFg  
{ iUl5yq  
nStartPos = input.readLong(); C~PrIM?  
nEndPos = input.readLong(); FA-""]  
} \ct)/  
input.close(); |~b.rKQt[  
} QiB^U^f  
catch(IOException e){e.printStackTrace ();} *oAv:8"iY  
catch(Exception e){e.printStackTrace ();} ^vXMX^*  
} 2GNtO!B.  
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private void processErrorCode(int nErrorCode) ?N2/;u>  
{ 4fPbwiKj  
System.err.println("Error Code : " + nErrorCode); KE3/sw0  
} vL"U=Q+/eY  
a+!#cQl  
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//停止文件下载 M>hHTa?W  
public void siteStop() l:v:f@M&
 
{ Rg3 Lo ?  
bStop = true; BX :77?9,+  
for(int i=0;i<nStartPos.length;i++) c,%9Fh?(  
fileSplitterFetch.splitterStop(); 1"J\iwN3  
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} 5MsE oLg  
} 7Io]2)V  
//负责部分文件的抓取 AfmGA9  
**FileSplitterFetch.java *sI`+4h[  
*/ 5~Vra@iab:  
package NetFox; smEKQHB  
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import java.io.*; >SO !{  
import java.net.*; T_ifDQX;  
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public class FileSplitterFetch extends Thread { '@1oM1  
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String sURL; //File URL .{+<o  
long nStartPos; //File Snippet Start Position <4,hr
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long nEndPos; //File Snippet End Position l \~w(8g<A  
int nThreadID; //Thread's ID ~\A(xmW}  
boolean bDownOver = false; //Downing is over c>+l3&`  
boolean bStop = false; //Stop identical p9w<|ZQ]:  
FileAccessI fileAccessI = null; //File Access interface (S/f!Dk&3  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException _@I<H\^  
{ S]3K5Z|  
this.sURL = sURL; TJS/O~=  
this.nStartPos = nStart; _l$
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this.nEndPos = nEnd; @]r,cPx0Y  
nThreadID = id; 6t9Q,+nJ  
fileAccessI = new FileAccessI(sName,nStartPos);//定位  QDCu  
} "~~Js~  
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public void run() FncK#hZ.  
{ >`Xikn(  
while(nStartPos < nEndPos && !bStop) J})G l  
{ MY>mP  
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try{ '0QrM,B9  
URL url = new URL(sURL); e1$T%?(&[  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); V8`o71p  
httpConnection.setRequestProperty("User-Agent","NetFox"); ^NZq1c  
String sProperty = "bytes="+nStartPos+"-"; vmW >$P  
httpConnection.setRequestProperty("RANGE",sProperty); AD_RU_a9  
Utility.log(sProperty); 0mcZe5RS  
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InputStream input = httpConnection.getInputStream();
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//logResponseHead(httpConnection); d:08@~#  
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byte[] b = new byte[1024]; V$U#'G>m  
int nRead; {%g]Ym=  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) z ((Y\vP  
{ ^P30g2gv>  
nStartPos += fileAccessI.write(b,0,nRead); +T]/4"^M  
//if(nThreadID == 1) Nl~'W  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); J1P jM
b}  
} ^0oOiZs  
P)7:G?OTx  
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Utility.log("Thread " + nThreadID + " is over!"); (jj=CLe  
bDownOver = true; vjNP  
//nPos = fileAccessI.write (b,0,nRead); ]w7wwU^^*U  
} pC=kvve  
catch(Exception e){e.printStackTrace ();}  ! @EZ  
} Er@'X0n  
} < cNJrer  
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2
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//打印回应的头信息 ,x(?7ZW>  
public void logResponseHead(HttpURLConnection con) p./9^S  
{ e`]x?t<U4/  
for(int i=1;;i++) lVb{bO9-O  
{ 2c)Ez?  
String header=con.getHeaderFieldKey(i); {|!> {  
if(header!=null) Epo/}y  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); z89
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Utility.log(header+" : "+con.getHeaderField(header)); o8uak*"{  
else \0)v5u  
break; 4%refqWK  
} VD.wO%9?)  
} :v$][jZ2  
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public void splitterStop() K9\r2w'T'  
{ +f
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bStop = true; TUy 25E  
} C-
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} AHB_[i'>7  
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/* /#Fz K  
**FileAccess.java 
c^F@9{I  
*//文件访问(定位，写) m#Y[EPF=|  
package NetFox; WALK@0E  
import java.io.*; 8T523VI  
H`T8ydNXa  
%(}%#-X  
public class FileAccessI implements Serializable{ )\PPIY>iP  
NG+%H1!$_  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 P*!~Z*"  
RandomAccessFile oSavedFile; `ElJL{Rn  
long nPos; KFhnv`a.0  
7W.z8>p  
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public FileAccessI() throws IOException n!?^:5=s  
{ zqCr'$  
this("",0); =38
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} XjFaP {  
bbG!Fg=qQ?  
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public FileAccessI(String sName,long nPos) throws IOException c~)H" n  
{ j V'~>  
oSavedFile = new RandomAccessFile(sName,"rw"); W<\*5oB%H  
this.nPos = nPos; GLiD,QX<  
oSavedFile.seek(nPos); GswV/V+u  
} rCsH 0:l8P  
h[& \OD,P  
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public synchronized int write(byte[] b,int nStart,int nLen) AVO$R\1YR  
{ .2f0e[J  
int n = -1; S<o\.&J  
try{ ]L;X Aj?  
oSavedFile.write(b,nStart,nLen); 7J|eL yj  
n = nLen; {1}p+dEK  
} um=qT)/D  
catch(IOException e) }&Ul(HR  
{ C<E;f]d  
e.printStackTrace (); 9RQw6rL  
} .B_a3K4'{^  
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P~@.(hed  
return n; +"3K)9H  
} dk.VH!uVb  
[J6q(}f  
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} EViDMp"  
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/* q/dja  
**SiteInfoBean.java lQt* LWd[  
*/ v0W/7?D  
package NetFox; 8gXf4A(N  
GcHZ&m4  
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public class SiteInfoBean { o]WG8Mo-  
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private String sSiteURL; //Site's URL ,H:{twc   
private String sFilePath; //Saved File's Path a{4RG(I_  
private String sFileName; //Saved File's Name  $&to(  
private int nSplitter; //Count of Splited Downloading File 4qg] oiT  
!~a1xI~s  
1'YksuYx6f  
public SiteInfoBean() V38v2LI  
{//nSplitter的缺省值为5 #RVN7-x  
//default value of nSplitter is 5 )jm u*D5N  
this("","","",5); Z)dE#A_X  
} wf/DLAC  
%z5P%F'5   
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) =7 ${bp!  
{ 3PRK.vf  
sSiteURL= sURL; {aYCrk1  
sFilePath = sPath;  &&sCaNb  
sFileName = sName; p<AzpkU,A  
this.nSplitter = nSpiltter; 8~eYN-#W&  
\ 0aa0=  
5d5q0bb  
} |c3Yh,Sv  
 mIkc+X  
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public String getSSiteURL() hwB>@r2  
{ DgRA\[c  
return sSiteURL; =d`/BDD  
} [;8vO=Z  
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public void setSSiteURL(String value) mZb[Fi  
{ ?j-;;NNf  
sSiteURL = value; @T8$/  
} ;OY*`(Id  
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{wyf>L0j  
public String getSFilePath() k=r)kkO)  
{ 6<+8[o  
return sFilePath; {fAj*,pzl  
} Q2 @Ugt$  
*d;D~"E<@  
- |j4u#z  
public void setSFilePath(String value) /ng+IC3  
{ [
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sFilePath = value; L#X!.  
} >djTJ>dl_u  
E#A}J:  
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public String getSFileName()  LAfv1  
{ KD)+&69  
return sFileName; X__>r ?oJ  
} _aLml9f W  
oiY&O]}  
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public void setSFileName(String value) #pm0T1+jW  
{ \"^.>+  
sFileName = value; j/Rm~!q  
} M,j3z#  
I:9jn"  
}xE}I<M  
public int getNSplitter() HLml:B[F(  
{ _6,Tb]  
return nSplitter; >84:1`  
} 39zwPoN>  
%juR6zB%8  
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public void setNSplitter(int nCount) aur4Ky> :  
{ [~_()i=Y  
nSplitter = nCount; U`h>[9  
} TaN]{k  
} Z?}yPsOb  
]E/~PV  
!04zWYHo  
/* _~_E(rTn  
**Utility.java ejuw+@ _  
*/ $<N!2[I L  
package NetFox; ^Td_B03)  
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(T]<  
public class Utility { }F~4+4B^  
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public Utility() 8A3pYW-  
{ }#h>*+Q  
t@(`24  
=Hs[peO*  
} .h;PMY+  
Bh\>2]~@a  
//线程睡眠 ue;o:>G  
public static void sleep(int nSecond) :~1sF_  
{ 'l| e}eti>  
try{ (pFPuV  
Thread.sleep(nSecond); j$z<
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} ]$VYzE2e  
catch(Exception e) 1sT%g}w@|  
{ |Qe#[Q7  
e.printStackTrace (); .<Lbv5m  
} ;F;"Uw  
} ;GgW&*|  
Zss `##  
//日志 GWU"zWli]z  
public static void log(String sMsg) fuQb h  
{ 6_s_2cr  
System.err.println(sMsg); PU6Sa-fQ2,  
} Hik :Sqpox  
tL;!!vg#V  
1gTW*vLM\  
public static void log(int sMsg) [= GVK  
{ 2KUm(B.I  
System.err.println(sMsg); ia!b0*<   
} Imi#$bF6  
} mF?GQls`  
k[6xuyY]  
z DP  
/* >brf7h  
**TestMethod.java oBm^RHTZ  
*/ #ZPU.NNT?  
package NetFox; Y~</vz+H  
^zMME*G  
7h3#5Y  
public class TestMethod { h#o3qY  
H.D1|sU  
/-.i=o]b  
public TestMethod() JMUk=p<\  
{ ///xx/weblogic60b2_win.exe /lC&'hT  
try{ [&Z3+/lR*  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ^+ hJ& 9W  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); :< )"G&  
SiteFileFetch fileFetch = new SiteFileFetch(bean); wClX3l>y  
fileFetch.start(); Z=B6fu*  
} :`9hgd/9  
catch(Exception e){e.printStackTrace ();} y}fF<qih'>  
{EoRY/]  
n>_EEw2/  
} -7^A_
!.  
?HP54G<{xz  
QJcaOXyMS  
public static void main(String[] args) Y\.ds%G  
{ cmzu @zq  
new TestMethod(); ]kN<N0;\d  
} bN,>,hj  
} /-#1ys#F=  
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