http断点续传简单实现（java)

/* ebB8.(k9G3  
**SiteFileFetch.java uy=E92n3  
*/ M4}zRr([.5  
package NetFox; +0n,>eDjg^  
import java.io.*; d7L|yeb"  
import java.net.*; k.#[h@Pm  
#K[6Ai=We}  
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public class SiteFileFetch extends Thread { ,6^V)F  
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SiteInfoBean siteInfoBean = null; //文件信息Bean )%(H'omvl  
long[] nStartPos; //开始位置 NE!]  
long[] nEndPos; //结束位置 uB3Yl
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FileSplitterFetch[] fileSplitterFetch; //子线程对象 @>hXh +!2h  
long nFileLength; //文件长度 --|L?-2k,  
boolean bFirst = true; //是否第一次取文件 u]QG^1.qYe  
boolean bStop = false; //停止标志 'xc=N  
File tmpFile; //文件下载的临时信息 o7s<G8;?  
DataOutputStream output; //输出到文件的输出流 UL\gcZ Zkl  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） QU^?a~r  
public SiteFileFetch(SiteInfoBean bean) throws IOException w<=-n;2  
{ se]QEd7]7  
siteInfoBean = bean; YH$whJ`W0  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); w,zgYX&  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); KH76Vts  
if(tmpFile.exists ()) +K*_=gHF.  
{ {FNq&)#`  
bFirst = false; r
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read_nPos(); -VRKQNT  
} $t42?Z=N&z  
else *6P)HU@  
{ {(qH8A  
nStartPos = new long[bean.getNSplitter()]; wg 6
 
nEndPos = new long[bean.getNSplitter()]; _,]@xFCOH  
} a6.0$'  
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} R//S(eU68\  
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public void run() ]5i]2r1  
{ (e6KSRh2fF  
//获得文件长度 S?LUSb  
//分割文件 iQ_^MzA  
//实例FileSplitterFetch i?pC[Ao-_  
//启动FileSplitterFetch线程 Z%O>|ozpq  
//等待子线程返回 8qQrJFm|3*  
try{ +%RB&:K7,  
if(bFirst) q|7$@H^*  
{ 0w ] pDj  
nFileLength = getFileSize(); gpzZs<ST  
if(nFileLength == -1) SI@Yct]<g  
{ !7fVO2m T  
System.err.println("File Length is not known!"); 9Kd:7@U  
} *%`jcF  
else if(nFileLength == -2) Hs6}~d  
{ B#;0{  
System.err.println("File is not access!"); [}bPkD  
} 7FD.3/  
else E'4dI:  
{ 66shr  
for(int i=0;i<nStartPos.length;i++) ,2_!hm/  
{ dsUY[X-<6  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 04cNi~@m  
} r:uW(<EP^  
for(int i=0;i<nEndPos.length-1;i++) _q dLA  
{ 2 VGGSLr  
nEndPos = nStartPos[i+1]; fE/|U|5L[  
} 8NzXe 7  
nEndPos[nEndPos.length-1] = nFileLength; U/I+A|S[  
} `h|>;u   
} 1$
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//启动子线程 h9 &V   
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; nH^RQ'19  
for(int i=0;i<nStartPos.length;i++) F|t_&$Is?  
{ O:3DIT1#>  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), i(@<KH  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), bZsg7[: C  
nStartPos,nEndPos,i); 3teanU`  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); f.SmCgG  
fileSplitterFetch.start(); =3?"s(9  
} =c(3EI'w  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), P",E/beV  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 2DbM48\E  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", +4%:q~C  
nEndPos = " + nFileLength); trC+Etc  
// fileSplitterFetch[nPos.length-1].start(); y()Si\9v  
E
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//等待子线程结束 \9t6#8  
//int count = 0; \4e6\6 +  
//是否结束while循环 nmrYBw>  
boolean breakWhile = false; Bpw<{U  
,"W.A  
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while(!bStop) Du2v,n5@  
{ !HP/`R  
write_nPos(); vAMr&[  
Utility.sleep(500); jL[ hB  
breakWhile = true; Y2,\WKa  
$"&U%3  
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for(int i=0;i<nStartPos.length;i++) hMiuv_EO!  
{ B=`"!?we  
if(!fileSplitterFetch.bDownOver) 9&`ejeD  
{ )c$)am\I{  
breakWhile = false; Z*r
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break; Ut xe  
} d@72z r  
} ^BFD -p  
if(breakWhile) op%?V:  
break;
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//count++; XiB]I5(hcc  
//if(count>4) g$f;  
// siteStop(); CxOBH89(  
} HBFuA.",  
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]'/ZSy,  
System.err.println("文件下载结束！"); ~t~5ctJ@  
} 4U*
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catch(Exception e){e.printStackTrace ();} H}$hk  
} E0i_sB~T  
;|Ja|@82  
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//获得文件长度 \#A=twp  
public long getFileSize() P00pSRQHD  
{ K{&b "Ba1  
int nFileLength = -1; 42m}c1R  
try{ Qb|.;_  
URL url = new URL(siteInfoBean.getSSiteURL()); CXsi  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); &Tf R].  
httpConnection.setRequestProperty("User-Agent","NetFox"); S}hg*mWn{$  
69v[*InSd  
]cv|A^  
int responseCode=httpConnection.getResponseCode(); E+&]96*Lby  
if(responseCode>=400) ewn/@;E  
{ d[9NNm*htC  
processErrorCode(responseCode); ,A>i)b
rc  
return -2; //-2 represent access is error CKTD27})  
} X; gN[  
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String sHeader; -^(NIl'  
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for(int i=1;;i++) N -]m <z>  
{ cg,_nG]i  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); }<wj~f([  
//Utility.log(in.readLine()); 8elT/Wl  
sHeader=httpConnection.getHeaderFieldKey(i); DT=!  
if(sHeader!=null) Ccocv>=Q&J  
{
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if(sHeader.equals("Content-Length")) /rNY;qXM  
{ pr-{/6j6  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); QsmG(1=  
break; L#e|t0'#  
} .~5cNu'#m  
} (!';  
else Oed&B  
break; 7#,
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} B%Yb+
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} N[}XLhbt  
catch(IOException e){e.printStackTrace ();} V,uhBMT#
  
catch(Exception e){e.printStackTrace ();} _W: S>ij(  
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 \~  
Utility.log(nFileLength); RU`TzD  
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return nFileLength; `.dTkL
 
} ^}8_tZs8\  
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//保存下载信息（文件指针位置） e<^tY0rR&  
private void write_nPos() 0nAeeVz|  
{ ,>
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try{ H[x9 7r  
output = new DataOutputStream(new FileOutputStream(tmpFile)); T^GdN_qF  
output.writeInt(nStartPos.length); 4(JxZ49  
for(int i=0;i<nStartPos.length;i++) GX_Lxc_<f  
{ {\t:{.F A  
// output.writeLong(nPos); y|KDh'Y  
output.writeLong(fileSplitterFetch.nStartPos); ^d"tymDd  
output.writeLong(fileSplitterFetch.nEndPos); E"Xi  
} :;"3k64  
output.close(); ,`|KNw5  
} d*3R0Q|#{  
catch(IOException e){e.printStackTrace ();} cf@#a@7m9  
catch(Exception e){e.printStackTrace ();} qRB7I:m-Wi  
} 7k3":2:  
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/KKX;L[D(  
//读取保存的下载信息（文件指针位置） v *:m|wl  
private void read_nPos() A|>a Gy  
{ wCvD4C.WH  
try{ kX1hcAa  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); zMrZ[AU  
int nCount = input.readInt(); t*Q12Q  
nStartPos = new long[nCount]; fWm;cDM H  
nEndPos = new long[nCount]; PfrW,R~r  
for(int i=0;i<nStartPos.length;i++) JsPuxu_  
{ kd\G>  
nStartPos = input.readLong(); .yWdlq##  
nEndPos = input.readLong(); Fr%KO)s2  
} uR"]w7=  
input.close(); +[2lS54"W4  
} `bC_J,>_  
catch(IOException e){e.printStackTrace ();} u gfV'  
catch(Exception e){e.printStackTrace ();} 5o~Z>  
} dbZPt~S'$  
Q|G[9HBI  
'`o+#\,b^%  
private void processErrorCode(int nErrorCode) m@c2'*&Y  
{ ;pB?8Z  
System.err.println("Error Code : " + nErrorCode); E/GI:}YUy_  
} DTIy/  
m dC. FO-  
j#p3
c  
//停止文件下载 G#% =R`k/  
public void siteStop() % 9WWBxS  
{ *
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bStop = true; *gT TI;:  
for(int i=0;i<nStartPos.length;i++) n(o Jb  
fileSplitterFetch.splitterStop(); %)aDh }  
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^$#Q_Y|  
} Y66 vJ<lM  
} o!H"~5Trv!  
//负责部分文件的抓取 E>V8|Hz;  
**FileSplitterFetch.java 3]VTQl{P  
*/ t1~*q)!Mo  
package NetFox; P7
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import java.io.*; $K G?d>wx  
import java.net.*; *@Qt*
f  
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public class FileSplitterFetch extends Thread { Ahebr{u  
X>wQYIi  
]CL70+[^9  
String sURL; //File URL L]tyL)  
long nStartPos; //File Snippet Start Position 6a,YxR\  
long nEndPos; //File Snippet End Position P2Eyqd8  
int nThreadID; //Thread's ID |F=^Cu,  
boolean bDownOver = false; //Downing is over 54)}^ftY^  
boolean bStop = false; //Stop identical yi%B5KF~Al  
FileAccessI fileAccessI = null; //File Access interface 7xd}J(l  

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7v:;`6Jb  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException PHOW,8)dZh  
{ WMC6dD_6e  
this.sURL = sURL; 0+H"$2/  
this.nStartPos = nStart; {l1;&y?  
this.nEndPos = nEnd; @O(\TIg  
nThreadID = id; ``\H'^{B  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 7:;V[/  
} FJ[(dGKeE  
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P~*fZ)\}F@  
public void run() qj/P4*6E  
{ EagI)W!s[  
while(nStartPos < nEndPos && !bStop) Fq3;7Cq=hD  
{ lk'RWy"pw  
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try{ L@ay4,e.bz  
URL url = new URL(sURL); s-DtkO  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); l;C_A;y\  
httpConnection.setRequestProperty("User-Agent","NetFox"); &S{F"z  
String sProperty = "bytes="+nStartPos+"-"; oc?VAF  
httpConnection.setRequestProperty("RANGE",sProperty); T<?;:MO88  
Utility.log(sProperty); D;E&;vP6%  
doa$ ;=wg  
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InputStream input = httpConnection.getInputStream(); XU54sk
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//logResponseHead(httpConnection); 93rE5eGs  
8;5/_BwMu  
+l#2u#e  
byte[] b = new byte[1024]; !`WuLhB`  
int nRead; .6hH}BM  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) B?4\IXek  
{ 8BN'fWl&E  
nStartPos += fileAccessI.write(b,0,nRead); Nf~<xK  
//if(nThreadID == 1) -Z@p   
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); O| 2Q- @D  
} r5"/EMieh  
E0|aI4S4  
*!Dzst-J3  
Utility.log("Thread " + nThreadID + " is over!"); bM'AD[  
bDownOver = true; ;Cy@TzO/|  
//nPos = fileAccessI.write (b,0,nRead); 3m^BYr*y^  
} ~:@H6Ke[  
catch(Exception e){e.printStackTrace ();} 4j*}|@x  
} l1??b  
} :)z_q!$j  
B?M+`;  
y/FisX  
//打印回应的头信息 )v9[/ ]*P  
public void logResponseHead(HttpURLConnection con) qq`RfZjL  
{ BAhC-;B#R  
for(int i=1;;i++) M Q6Y^,B  
{ ,y>Na{@Y  
String header=con.getHeaderFieldKey(i); @K/Ia!Lw  
if(header!=null) 4|(?Wt)5  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); j.
6kjQN  
Utility.log(header+" : "+con.getHeaderField(header)); 2*|]#W
 
else UdGoPzN  
break; \x!>5Z Y  
} LWI~m2  
} @FTi*$Ix  
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public void splitterStop() V~=)#3]`[  
{ y AWDk0bx  
bStop = true; Yx"z&J9p  
} --9mTqx  
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} X=3@M_Jzo  
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/* )>fi={!=c  
**FileAccess.java e-VLU;  
*//文件访问(定位，写) !r
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package NetFox; j#&  
import java.io.*; >=V+X"\Z  
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a3;.{6el)H  
public class FileAccessI implements Serializable{ H[D/Sz5`  
]c)SVn$6  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 BGX@n#:  
RandomAccessFile oSavedFile; }]I?vyQ#V  
long nPos; )hug<D *h  
#*!$!c{  
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public FileAccessI() throws IOException K>[H@|k\k  
{ GHy#D]Z  
this("",0); `y}
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} q8Dwu3D  
i7rq;t<  
9QMn%8=j  
public FileAccessI(String sName,long nPos) throws IOException ))`Zv=y"  
{ 9^u?v`!  
oSavedFile = new RandomAccessFile(sName,"rw"); qN@a<row&~  
this.nPos = nPos; o!~
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oSavedFile.seek(nPos); to3J@:V8e  
} d<'xpdxc  
A
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+&
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public synchronized int write(byte[] b,int nStart,int nLen) Q(UGwd1  
{ S F>D:$a  
int n = -1; .jp]S4~  
try{ \#aVu^`eX  
oSavedFile.write(b,nStart,nLen); ?^~"x.<nr  
n = nLen; E0Q"qEvU  
} R(sM(x5a`  
catch(IOException e) 0?SLRz8  
{ Jdn*?hc+  
e.printStackTrace (); d 4]%Wdvf  
} g5Rm!T+@I<  
s{e(- 7'  
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return n; $)Yog]}  
}  3Mx@  
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} pGY]VwY  
7X(]r1-+\  
:OCuxSc%5  
/* \'Ta8  
**SiteInfoBean.java zU~..;C  
*/ <im<(=m9  
package NetFox; M"^Vf{X^  
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public class SiteInfoBean { _wNPA1q0J  
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|*KS<iHr%  
private String sSiteURL; //Site's URL P]"deB|  
private String sFilePath; //Saved File's Path P/Kit?kngS  
private String sFileName; //Saved File's Name hFMst%:y$  
private int nSplitter; //Count of Splited Downloading File V:BX"$J1  
nud=uJ"(  
iIaT1i4t.  
public SiteInfoBean() ex\W]5  
{//nSplitter的缺省值为5 H@E")@92  
//default value of nSplitter is 5
_}OJPahw  
this("","","",5); GQ2PmnV+  
} @b\ S.  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) b$O_L4CP  
{ 9
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sSiteURL= sURL; lt6
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sFilePath = sPath; UZP6x2:=  
sFileName = sName; ;#s}b1  
this.nSplitter = nSpiltter; liqR#<  
iN_D8dI  
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} _1<'"u#6w  
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public String getSSiteURL() p*`SGX  
{ ^Opy6Bqb  
return sSiteURL; neh;`7~5@K  
} H:-A; f!Z  
x$GsDV  
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public void setSSiteURL(String value) l(#ke  
{ Hpi%9SAM  
sSiteURL = value; `n`"g<K)Q  
} oD#>8Aws  
@f{_=~+  
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public String getSFilePath() vA"niO  
{ RP,:[}mPl  
return sFilePath; H [Lt%:r  
} ouVjZF@kS  
;,=h59`  
F|?'9s*;6G  
public void setSFilePath(String value) :e]9T3Q  
{ pp]_/46nN  
sFilePath = value; +K%pxuVh  
} pzq;vMr  
{HHh.K  
eKVALUw  
public String getSFileName() w,Zx5bBg%  
{ 0<@KDlF  
return sFileName; dA1 C)gLi  
} dHG Io  
8b:clvh  

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public void setSFileName(String value) )p<fL  
{ AB"1(PbG  
sFileName = value; ZSPgci  
} W 9Vz[  
*el(+ib%  
yYToiW *  
public int getNSplitter() n<?SZ^X{,/  
{ sr+gD*@h  
return nSplitter; #_?TIY:h  
} dGsS<@G  
3X$Q,  
iog # ,  
public void setNSplitter(int nCount) 8jggc#.  
{ 5, -pBep<  
nSplitter = nCount; wI! +L&Q  
} t0e{|du  
} M_h8#7{G  
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/* \ I^nx+l  
**Utility.java W""*hJ  
*/ O[IR|  
package NetFox; q*[!>\Z8  

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N )zPxQ  
public class Utility { U[
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public Utility() /WgPXEB  
{ =Y&9 qt  
?aFr8i:)M  
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} 5[,+\  
0{?:FQ#  
//线程睡眠 <E>7>ZL  
public static void sleep(int nSecond) 5=Kq@[(4  
{ C}mYt/
  
try{ eC6>yD6D  
Thread.sleep(nSecond); Y^R?Q'  
} {gFAvMj#  
catch(Exception e) %/l-A pu  
{ 'y4zBLY  
e.printStackTrace (); g.I(WJX0  
} -ca7x`yo  
} .[T'yc:=  
EkJVFHfh  
//日志 nW|'l^&  
public static void log(String sMsg) |}K  
{ E?Zb~xk  
System.err.println(sMsg); +65oC x  
} \G$QNUU  
@[MO,J&h  
kSB  
public static void log(int sMsg) VK2@2`$  
{ [D3+cDph  
System.err.println(sMsg); v:rD3=M-  
} 6exI_3A4jh  
} YBX)eWslK  
(U|)xA]y!  
XC|*A$x,  
/* |',M_ e]  
**TestMethod.java m`hGDp3  
*/ f).*NX  
package NetFox; CifA,[l34  
x3Nkp4=Xd  
4|[<e-W  
public class TestMethod { TC qkm^xv  
NWEhAj<w  
7\I
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public TestMethod() tNK^z7Dm  
{ ///xx/weblogic60b2_win.exe oW0gU?Rr)u  
try{ vO\:vp4fH  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 7\mDBG  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); :?HSZocf  
SiteFileFetch fileFetch = new SiteFileFetch(bean); %'N$lF"]  
fileFetch.start(); ,H>
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} XZ.7c{B<  
catch(Exception e){e.printStackTrace ();} wJ6_I$>  
:qxm !P  
RX:R*{]-  
} -Q6(+(7_|  
9khjwt  
{!L=u/qs"  
public static void main(String[] args) vR7ctav  
{ xEjx]w/&  
new TestMethod(); U+-F*$PO+  
} Pp,Um(  
} mge#YV::  
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