http断点续传简单实现（java)

/* -d:Jta!}{  
**SiteFileFetch.java |#N&akC  
*/ _v]MsT-q  
package NetFox; d m%8K6|  
import java.io.*; ^_
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import java.net.*; }*"p?L^p{  
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public class SiteFileFetch extends Thread { y"wShAR  
BIL Lq8)  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 4H]L~^CD  
long[] nStartPos; //开始位置 M
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long[] nEndPos; //结束位置 k|d+#u[Mj@  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Owk|@6!  
long nFileLength; //文件长度 <Q?F?.^e  
boolean bFirst = true; //是否第一次取文件 >[*qf9$  
boolean bStop = false; //停止标志 _:27]K:  
File tmpFile; //文件下载的临时信息 Yg1X  
DataOutputStream output; //输出到文件的输出流 |ZBI *  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 1|wL\I  
public SiteFileFetch(SiteInfoBean bean) throws IOException q5:N2Jmo?z  
{ I~XSn>-H  
siteInfoBean = bean; "'\$ g[k  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); \)|hogI|f  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); d6 5L!4  
if(tmpFile.exists ()) 5XBH$&Td  
{ V "h +L7T  
bFirst = false; v_-dx  
read_nPos(); OI*Xt`  
} G'A R`"F  
else BThrO d  
{ =C.$ UX  
nStartPos = new long[bean.getNSplitter()]; D d</`iUq  
nEndPos = new long[bean.getNSplitter()]; ixD)VcD-f  
} w+CA1q<  
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} b1?'gn~  
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public void run() Y/zj[>  
{ @J`"[%U  
//获得文件长度 '1s0D]  
//分割文件 "1M[5\Ax  
//实例FileSplitterFetch r\V ={p  
//启动FileSplitterFetch线程 @6T/Tdz  
//等待子线程返回 hZ  
try{ `RL"AH:+  
if(bFirst) wDe& 1(T^  
{ ~FG]wNgS  
nFileLength = getFileSize(); ut7zVp<"  
if(nFileLength == -1) 81 sG  
{ 4@# `t5H  
System.err.println("File Length is not known!"); DN57p!z
 
} ^,T(mKS  
else if(nFileLength == -2) ckE-",G  
{ Qn)a/w-  
System.err.println("File is not access!"); eV?2LtT#5  
} + @s"zp;F  
else @QPz#-  
{ YGCL2Y  
for(int i=0;i<nStartPos.length;i++) {[?(9u7R  
{ _.Uh)-yR  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Cd}<a?m,  
} 'kO!^6=4M  
for(int i=0;i<nEndPos.length-1;i++) nk's_a*Z  
{ ~%kkeh\j  
nEndPos = nStartPos[i+1]; fHd#u%63K  
} %2V?,zY@  
nEndPos[nEndPos.length-1] = nFileLength; -fW*vE:  
} z/@slT  
} ,M ^<CJ  
p]2128kqx  
K} X&AJ5A  
//启动子线程 Wf>R&o6tr  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Sw,+p  
for(int i=0;i<nStartPos.length;i++) ud@%5d  
{ 5IjGm  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 4yA+h2  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), EDl!w:  
nStartPos,nEndPos,i); 8\A#CQ5b  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 84zSK)=Y  
fileSplitterFetch.start(); -3Z,EaG^  
} 
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// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ~YWQ2]  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); w;:*P  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", B7E:{9l~s{  
nEndPos = " + nFileLength); j@3Q;F0ba  
// fileSplitterFetch[nPos.length-1].start(); ShP^A"Do  
LG|fq/;  
jZkcBIK2  
//等待子线程结束 1FL~ndJs  
//int count = 0; u(F_oZ~  
//是否结束while循环 h_3E)jc  
boolean breakWhile = false; 3J|F?M"N7  
qvKG-|j  
A>
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while(!bStop) ?(F6#"
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{ sW'AjI  
write_nPos(); Y0dEH^I  
Utility.sleep(500); Y>dzR)~3[  
breakWhile = true; '9Xu p  
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=M[bnq*\  
for(int i=0;i<nStartPos.length;i++) i
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{ 4=.89T#<  
if(!fileSplitterFetch.bDownOver) !v_|zoCEj  
{ #3@rS  
breakWhile = false; x$.^"l-vX  
break; $)ijN^hV  
} dI@(<R  
} %XoiVl
T@:  
if(breakWhile) 03qQ'pq  
break; bL+_j}{:N  
FF(#]vz'  
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//count++; CR`Q#Yi  
//if(count>4) u=?.}Pj  
// siteStop(); BB!THj69a6  
} Ms5ap<q#  
6azGhxh  
WwBOM~/`2  
System.err.println("文件下载结束！"); j@U]'5EVB  
} r?lf($D*  
catch(Exception e){e.printStackTrace ();} ll<Xz((o  
} 0y" $MC v  
DJXmGt]  
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//获得文件长度 0w\
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public long getFileSize()
:uq\+(9  
{ QQ*hCyw!  
int nFileLength = -1;
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try{ p$NQyS5C"S  
URL url = new URL(siteInfoBean.getSSiteURL()); Ustv{:7v  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Q_Q''j(r6b  
httpConnection.setRequestProperty("User-Agent","NetFox"); jk; clwyz/  
[#<-ZC#T*  
?wiCQ6*$  
int responseCode=httpConnection.getResponseCode(); fcRxp{*zO  
if(responseCode>=400) <CYd+! (  
{ g:'xae/]S  
processErrorCode(responseCode); *
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return -2; //-2 represent access is error H1pO!>M  
} _(W+S`7Z  
'8RsN-w  
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String sHeader; <ktrPlNuM  
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xaq-.IQAM$  
for(int i=1;;i++) $<dH?%!7  
{ ?>D+ge  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Xy|So|/bKd  
//Utility.log(in.readLine()); <Dl*l{zba  
sHeader=httpConnection.getHeaderFieldKey(i); Xk~D$~4<  
if(sHeader!=null) =V,mtT  
{ =1FRFZI!j  
if(sHeader.equals("Content-Length")) ?/
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{ &=@IzmA  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 3Gp$a;g  
break; fIx+ILs  
} GfxZ'VIn  
} >a!/QMh  
else m)ky*"(  
break; Go`vfm"S  
} vjbASFF0=  
} 9tU]`f  
catch(IOException e){e.printStackTrace ();} tVYF{3BhA  
catch(Exception e){e.printStackTrace ();} }Sm(]y  
SB;&GHq"n  
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Utility.log(nFileLength); 7X`g,b!  
IA fcT!{  
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return nFileLength; uanhr)Ys  
} aq>kTaz  
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JK7G/]j+Ez  
//保存下载信息（文件指针位置） D
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private void write_nPos() m<<+  
{ A]_7}<<N  
try{ \0^Kram>
 
output = new DataOutputStream(new FileOutputStream(tmpFile)); |0&IXOW"XF  
output.writeInt(nStartPos.length); ]{;gw<T  
for(int i=0;i<nStartPos.length;i++) wm+};L&_  
{ Hc;[Cs0  
// output.writeLong(nPos); =Pyj%4Rs  
output.writeLong(fileSplitterFetch.nStartPos); <v"R.<  
output.writeLong(fileSplitterFetch.nEndPos); 7m47rJyW4  
} E'f{i:O"~  
output.close(); 3p$?,0ELH  
} 0.Q Ujw  
catch(IOException e){e.printStackTrace ();} PF0_8,@U  
catch(Exception e){e.printStackTrace ();} s-NX 
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} B5,N7z34F  
Gf%~{@7=u  
(=FRmdeYl1  
//读取保存的下载信息（文件指针位置） (fhb0i-  
private void read_nPos() 8$]1M,$r  
{ xf'V{9*  
try{ mn'A9er  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); K,tQ!kk  
int nCount = input.readInt(); L@rcK!s,lD  
nStartPos = new long[nCount]; xEa\f[.An  
nEndPos = new long[nCount]; 7kC^ 30@T3  
for(int i=0;i<nStartPos.length;i++) mwO6g~@`  
{ NYhB'C2  
nStartPos = input.readLong(); ~kV/!=  
nEndPos = input.readLong(); b8H{8{wi|  
} `T1  
input.close(); M^A48u{,"  
} ,S\CC{!  
catch(IOException e){e.printStackTrace ();} n5|fHk^s  
catch(Exception e){e.printStackTrace ();} {aZ0;  
} "mo?* a$Sk  
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private void processErrorCode(int nErrorCode) oE6tauQn  
{ mb1FWy=3  
System.err.println("Error Code : " + nErrorCode); iG$!6;w<  
} -+-?w|}qV  
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~"gA,e-)  
//停止文件下载 p;a,#IJu  
public void siteStop() vN}#Kc\  
{ DmK57V4L^  
bStop = true; VCYwzB  
for(int i=0;i<nStartPos.length;i++) \eTwXe]Pv  
fileSplitterFetch.splitterStop(); _r#Z}HK  
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Y+pHd\$-4  
} _=r6=.  
} 3l]lwV  
//负责部分文件的抓取 RIR\']WN  
**FileSplitterFetch.java A.F%Ycq  
*/ Lpkyoh v  
package NetFox; ';k5?^T  
rCEyQ)R_}  
 y`iBFC;_  
import java.io.*;
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import java.net.*; z9f-.72"X  
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public class FileSplitterFetch extends Thread { UsG~row:!  
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String sURL; //File URL `?H]h"{7Q  
long nStartPos; //File Snippet Start Position _oL?*ks  
long nEndPos; //File Snippet End Position AF{\6<m  
int nThreadID; //Thread's ID iO{h
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boolean bDownOver = false; //Downing is over PN%zIkbo  
boolean bStop = false; //Stop identical sfH_5 #w  
FileAccessI fileAccessI = null; //File Access interface r+!YIk  
D
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException y
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{ J-:.FKf\5l  
this.sURL = sURL; Eh`7X=Z7E  
this.nStartPos = nStart; ?PxP% $hS  
this.nEndPos = nEnd; _RYxD"my  
nThreadID = id; L- iy  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 l9~e". ~'  
} .<?GS{6 N  
$p8xEcQdU#  
t,Lrfv])  
public void run() hNiE\x  
{ g'f@H-KCD  
while(nStartPos < nEndPos && !bStop) ;>hO+Wo  
{ >=lC4Tu  
;}WeTA_-[  
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try{ f5"k55}  
URL url = new URL(sURL); f)rq%N &  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); }Bh8=F3O Q  
httpConnection.setRequestProperty("User-Agent","NetFox"); HWAdhDZ  
String sProperty = "bytes="+nStartPos+"-"; gaxsv[W>^  
httpConnection.setRequestProperty("RANGE",sProperty); ;;Y!^^g  
Utility.log(sProperty); uc{Ihw  
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{W`%g^Z|H  
InputStream input = httpConnection.getInputStream(); 8%mu8l  
//logResponseHead(httpConnection); P5V}#;v  
/HE
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(/YHk`v2  
byte[] b = new byte[1024]; Es`Px_k  
int nRead; g-k|>-h
 
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) *R,5h2;  
{ 7+cO_3AB  
nStartPos += fileAccessI.write(b,0,nRead); **0~K";\  
//if(nThreadID == 1)
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// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); AN m d!  
} aK~8B_5k8  
[aLI '  
;1=1:S8  
Utility.log("Thread " + nThreadID + " is over!"); 2.y-48Nz  
bDownOver = true; iVr JQ  
//nPos = fileAccessI.write (b,0,nRead); Dpac^ST  
} U>SShpmZA  
catch(Exception e){e.printStackTrace ();} :Ov6_x]*  
} Q\vpqE!9  
} e{H=dIa+  
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I][*j  
//打印回应的头信息 !|uWH  
public void logResponseHead(HttpURLConnection con) W*:.Gxv]  
{ *>}@7}f  
for(int i=1;;i++) S13nL^=i  
{ gJ+'W1$/  
String header=con.getHeaderFieldKey(i); %2{ye  
if(header!=null) RP|`HkP-2  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); R\f+SvE  
Utility.log(header+" : "+con.getHeaderField(header)); e`s ~.ZF  
else 1I6px$^E\  
break; TX/Xt7#R:  
} v1JzP#  
} M_f:A  
.{^5X)  
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public void splitterStop() g
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{ Z{d^-  
bStop = true; %1L,Y  
} C) s5D  
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q2j{tP#  
} Q&;9x?e  
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"sCRdx]_  
/* eByz-,{P  
**FileAccess.java b%`1cV  
*//文件访问(定位，写) 6 "sSoj  
package NetFox; x,-75  
import java.io.*; {P./==^0  
p l0\2e)  
reWot&;  
public class FileAccessI implements Serializable{ )akoa,#%6c  
p2](_}PK  
//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; +6\Zj)  
long nPos; \2$|Ei7  
M }D}K\)  
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public FileAccessI() throws IOException >GRxHK@G  
{ h]gp^?=  
this("",0); pnOAs&QAm  
} abjQ)=u  
t{96p77)=  
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public FileAccessI(String sName,long nPos) throws IOException 6&x@.1('z  
{ wHy!CP%  
oSavedFile = new RandomAccessFile(sName,"rw"); R/YqyT\SM  
this.nPos = nPos; Rm( "=(  
oSavedFile.seek(nPos); :o3N;*o>)0  
} 3w'tH4C[Y  
L8B!u9%  
w?[upn:K  
public synchronized int write(byte[] b,int nStart,int nLen) ms]sD3z/W+  
{ mzgfFNm^G)  
int n = -1; (9a^$C
*  
try{ ZECfR>`x  
oSavedFile.write(b,nStart,nLen); fJg+Ryo  
n = nLen; !Uo4,g6r+  
} @VEb{ w[H  
catch(IOException e) yWSGi#)1  
{ GbI/4<)l}  
e.printStackTrace (); 2?Vd5xkt  
} uY To9A  
hZb_P\1X  
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return n; ?r4>"[  
} >t+P(*u  
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} OyIw>Wfv  
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/* HoAy_7-5  
**SiteInfoBean.java .%-8 t{dt  
*/ V7/Rby Q  
package NetFox; i|kRK7[6B  
#'}*dy/  
{!`6zBsP  
public class SiteInfoBean { EU#^7  
|.dRily+  
7tp36TE  
private String sSiteURL; //Site's URL '"s@enD0y  
private String sFilePath; //Saved File's Path XjBD{m(  
private String sFileName; //Saved File's Name rJB}qYD  
private int nSplitter; //Count of Splited Downloading File 1Y,Z %d  
e3\T)x&=  
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public SiteInfoBean() Zd+bx*rD  
{//nSplitter的缺省值为5  \=o-  
//default value of nSplitter is 5 k?}Zg*  
this("","","",5); hbn([+xY  
} V]^$S"Tv  
HaYo!.(Fv  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) []T8k9g/-  
{ 7:@'B|  
sSiteURL= sURL; Ys7]B9/1O  
sFilePath = sPath; 7EJ+c${e.-  
sFileName = sName; *1"+%Z^  
this.nSplitter = nSpiltter; 8Fub<UhJ  
4M T 7`sr  
fQFk+C  
} 'ga/  
9BB=YnKE  
y`Z\N   
public String getSSiteURL() Y-9I3?ar  
{ .)3<Q}>  
return sSiteURL; HZOMlOZ  
} OrW  
JGZBL{8  
"M0z(NkH  
public void setSSiteURL(String value) 4Tc~b3\!Y  
{ IGgL7^MF  
sSiteURL = value; s#MPX3itK  
} }B^tL$k  
E`J@hl$N  
]@TCk8d$0  
public String getSFilePath() (?];VG  
{ +ai< q>+  
return sFilePath; ^^Vg~){4  
} F[MFx^sT{  
R-14=|7a-  
r|Z{-*`  
public void setSFilePath(String value) ABkl%m6xf  
{ s[N@0  
sFilePath = value; ,//S`j$S  
} SWLo|)@[/  
0{mex4  
0\$2X- c  
public String getSFileName() `_h&glMJ,q  
{ `u\n0=go  
return sFileName; 4K74=r),i  
} JS77M-Ac  
`h;[TtIX4  
=M-p/uB]  
public void setSFileName(String value) X?Au/  
{ pot~<d`:K"  
sFileName = value; 7z-[f'EIUI  
} V.Mry`9-  
GthYzd:'hJ  
WhDJ7{D  
public int getNSplitter() _B0L.eF  
{ Pc9H0\+Xk  
return nSplitter; ]f3>-)$*  
} +|rj4j)L&'  
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o  
public void setNSplitter(int nCount) W>LR\]Ti@  
{ E'8;
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nSplitter = nCount; 1&2>LE/P  
} 4I7>f]=)  
} nP$9CA  
54/=G(F  
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/* ])!*_  
**Utility.java Y$zSQ_k;U  
*/  @8 6f  
package NetFox; NO3/rJ6-  
g+lCMW\  
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public class Utility { ME dWLFf  
[gB+C84%%  
u&NV,6Fj2[  
public Utility() b]y2+A.
n  
{ |{8Pb3#U  
{8OCXus3m  
a =QCp4^  
} /o[w4d8  
4Up/p&1@  
//线程睡眠 Vc2`b3"Br  
public static void sleep(int nSecond) C]#,+q*  
{ }*-@!wc-N  
try{ l\mPHA23  
Thread.sleep(nSecond); ]oxZ77ciL  
} &vJH$R  
catch(Exception e) G?ZXWu.  
{ 9my^Y9B  
e.printStackTrace (); ! z**y}<T  
} @VBcJ{e,  
} Y}/-C3)  
. ^u,.  
//日志 >bxS3FCX  
public static void log(String sMsg) ""H?gsL[  
{ s>en  
System.err.println(sMsg); p[-O( 3Y  
} '7/)Ot(  
w@pPcZ>z/  
j6YO
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public static void log(int sMsg) 74u&%Rj  
{ nEfK53i_  
System.err.println(sMsg); rUl+  
} :+Z%; Dc  
} j [a(#V{  
ebq4g387X  
#QPjkR|\  
/* ;j7#7MN2_E  
**TestMethod.java Bwrx*J  
*/ TseGXYH  
package NetFox; s.#`&Sd>  

@co S+t  
B[}6-2<>?C  
public class TestMethod { >usL*b0%  
==B6qX8T  
S@Y39  
public TestMethod() i1085ztN  
{ ///xx/weblogic60b2_win.exe  bLL2  
try{ [?gP;,  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); i@q&5;%%  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); YQ}o?Q$z  
SiteFileFetch fileFetch = new SiteFileFetch(bean); H+#FSdy#  
fileFetch.start(); -4K5-|>O  
} I'Hf{Erw  
catch(Exception e){e.printStackTrace ();} TzZq(?V  
_GPe<H  
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} KoRV%@I  
7^Uv7<pw  
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public static void main(String[] args) h1RSVp+?n  
{ <q836]aaA  
new TestMethod(); W)/#0*7  
} ("@!>|H  
} =M1I>  
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