http断点续传简单实现（java)

/* kmP]SO?tx  
**SiteFileFetch.java ZX9TYN  
*/ a_f
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package NetFox; cW@Zd5&0S  
import java.io.*; +Elf
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import java.net.*; /Z'L^L
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public class SiteFileFetch extends Thread { &Sw%<N*r  
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}B\a<0L/  
SiteInfoBean siteInfoBean = null; //文件信息Bean g{OwuAC_  
long[] nStartPos; //开始位置 z> Rsi  
long[] nEndPos; //结束位置 dCi?SIN  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 $'BSH4~|.  
long nFileLength; //文件长度 P
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boolean bFirst = true; //是否第一次取文件 e:fy#,HEj{  
boolean bStop = false; //停止标志 EofymAi%  
File tmpFile; //文件下载的临时信息 >,gg5<F-E  
DataOutputStream output; //输出到文件的输出流 >s>1[W@*  
52:HNA\E/  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） R!\_rc1/  
public SiteFileFetch(SiteInfoBean bean) throws IOException vK|E>nL  
{ 8@i7pBl@  
siteInfoBean = bean; $WyD^|~SF  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); l=S35og  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); e6@=wnoX u  
if(tmpFile.exists ()) n.'8A(,r3  
{ x+Ttl4  
bFirst = false; H?<N.Dq  
read_nPos(); #lmB AL~3  
} >`Y.+4mE  
else ^Cu\VV  
{ ?pr9f5  
nStartPos = new long[bean.getNSplitter()]; PF)jdcX  
nEndPos = new long[bean.getNSplitter()]; adCU61t  
} `^u>9v-+'  
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} 27 ]':A4_  
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public void run() _4"mAPt  
{ }Lc-7[/  
//获得文件长度 bLlKe50  
//分割文件 ~ELNyI11  
//实例FileSplitterFetch 2`7==?  
//启动FileSplitterFetch线程 UW N*j_9i  
//等待子线程返回 Oft-w)cYz,  
try{ -I*^-+>H  
if(bFirst) qkt0**\  
{ Y2a5bc P  
nFileLength = getFileSize(); zKw`Md  
if(nFileLength == -1) qaiNz S@q  
{ E
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System.err.println("File Length is not known!"); |L%Z,:yO  
} aoM
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else if(nFileLength == -2) ~zHjMo2  
{ =5J7Hw&K  
System.err.println("File is not access!"); e<3K;Q  
} K&vF0*gN3  
else R<\F:9  
{ od IV:(  
for(int i=0;i<nStartPos.length;i++) fsJ9bQm/  
{ U{7w#>V .  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ]RPs|R?  
} ;YA(|h<  
for(int i=0;i<nEndPos.length-1;i++) Dd'm U  
{ WKC.$[T=  
nEndPos = nStartPos[i+1]; /(u}KMR!f  
} jr)1(**  
nEndPos[nEndPos.length-1] = nFileLength; (!ZM{Js%  
} Huy5-[)15  
} .<jr0,i  
}Mstjm  
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//启动子线程 $;
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; "S8uoSF`>  
for(int i=0;i<nStartPos.length;i++) vMA]j>>  
{ n!YKz"$  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), hBS.a6u1'd  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 'Q|M'5'  
nStartPos,nEndPos,i); [b6R%  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 1pt%Kw*@j  
fileSplitterFetch.start(); {K+icTL3  
} (KFCs^x7wG  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), %SX|o-B~.o  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); iX0i2ek  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", \]</w5 Pi,  
nEndPos = " + nFileLength); 4lr(,nPRD  
// fileSplitterFetch[nPos.length-1].start(); n"c)m%yZ  
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$w)!3c4  
//等待子线程结束 J2::'Hw*s  
//int count = 0; =Q+;=-1  
//是否结束while循环 NG--6\  
boolean breakWhile = false; n,jKmA  
hlV=qfc  
Z'4./  
while(!bStop) Wi*.TWz
3  
{ s%qF/70'  
write_nPos(); tX5"UQA  
Utility.sleep(500); wb]%m1H`:  
breakWhile = true; /M|262%  
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for(int i=0;i<nStartPos.length;i++) ,=UK}*e"  
{ E0Y-7&Fv  
if(!fileSplitterFetch.bDownOver) RTE8Uq36  
{ WlB  
breakWhile = false; b<a4'M  
break; 24E}<N,g  
} /JFUU[W  
} + ,%&e  
if(breakWhile) \SN&G`o<  
break; ZjgsR|i  
I%r{]-Obr-  
!F1M(zFD  
//count++; R@/"B8H  
//if(count>4) 9{(.Il J>  
// siteStop(); 
d9B]fi}  
} GR +[UG  
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System.err.println("文件下载结束！"); "]"|"0#i  
} 1M}5>V{  
catch(Exception e){e.printStackTrace ();} /.3}aj;6  
} Gf,`  
IEXt:  
}@;ep&b*  
//获得文件长度 UELy"z R  
public long getFileSize() q#T/  
{ 01}C^iD  
int nFileLength = -1; Q~OxH'>>(  
try{ H| 8Qp*  
URL url = new URL(siteInfoBean.getSSiteURL()); >d,jKlh^.%  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Z1 Bp+a3  
httpConnection.setRequestProperty("User-Agent","NetFox"); 6A>dhU  
b6Wqr/  
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int responseCode=httpConnection.getResponseCode(); 8kU!8^mH  
if(responseCode>=400) G+%zn|  
{ M@`;JjtSA  
processErrorCode(responseCode); pk^K:Xs}  
return -2; //-2 represent access is error ;g@4|Ro  
} T?x[C4wf+  
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&7`^i.fh)  
String sHeader; JTr vnA  
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nSW=LjrO~<  
for(int i=1;;i++) eCqHvMp  
{ K%a%a6k`  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); t/cY=Wp  
//Utility.log(in.readLine()); $"FQj4%d  
sHeader=httpConnection.getHeaderFieldKey(i); jBgP$g  
if(sHeader!=null) @ o3T  
{ jF0jkj1&/[  
if(sHeader.equals("Content-Length")) {)BTR
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{ gu0j.XS^  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); \9cG36  
break; eM$
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} [Jogt#Fj ]  
} ?\t#1"d  
else %/|9@er  
break; eO?p*"p"F  
} } ud0&Oe{  
} Fx;QU)1l3  
catch(IOException e){e.printStackTrace ();} $})g?Q  
catch(Exception e){e.printStackTrace ();} K? y[V1,  
x[$z({Yf  
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Utility.log(nFileLength); 4x  
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return nFileLength; $oj:e?
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} PmKeF}  
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//保存下载信息（文件指针位置） PcA2/!a  
private void write_nPos() )TVFtI=,NN  
{ mS~o?q-n  
try{ <,[cQ
I/  
output = new DataOutputStream(new FileOutputStream(tmpFile)); J%x\=Sv  
output.writeInt(nStartPos.length); BQ=PW|[  
for(int i=0;i<nStartPos.length;i++) yzerOL  
{ *M:B\D  
// output.writeLong(nPos); n/SwP  
output.writeLong(fileSplitterFetch.nStartPos); 3QG7C{  
output.writeLong(fileSplitterFetch.nEndPos); %kS(LlL+6  
} +
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output.close(); 1guJG_;z  
} `%+Wz0(K  
catch(IOException e){e.printStackTrace ();} QR%mj*@Wle  
catch(Exception e){e.printStackTrace ();} $wo?!gt  
} ~8GFQ ph  
)%`^xR  
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//读取保存的下载信息（文件指针位置） k@/sn(x  
private void read_nPos() fh](K'P#^  
{ p-Kz-+A[  
try{ CIb2J)qev  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ti I.W  
int nCount = input.readInt(); M luVx'  
nStartPos = new long[nCount]; GBRa.;Kk  
nEndPos = new long[nCount]; /atW8 `&  
for(int i=0;i<nStartPos.length;i++) Q36qIq_0e  
{ V:VO[e<e  
nStartPos = input.readLong(); ~GL]wF2#  
nEndPos = input.readLong(); G LIi6  
} aqj@Cjk4Z  
input.close(); gk"$,\DI  
} (NF~Ck$#q  
catch(IOException e){e.printStackTrace ();} _3TY,l~  
catch(Exception e){e.printStackTrace ();} )N7Y^CN~  
} Qa-K$dm%  
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private void processErrorCode(int nErrorCode) L)@?e?9  
{ J|~MC7#@q  
System.err.println("Error Code : " + nErrorCode); B56L1^7  
} 3E!|<q$z  
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//停止文件下载 7f0lQ  
public void siteStop() 3'cE\u  
{ &Low/Y'.jJ  
bStop = true; |}(`kW  
for(int i=0;i<nStartPos.length;i++) FaDjLo2'o  
fileSplitterFetch.splitterStop(); mP0yk
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,*7 (%k^`  
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} (Iaf?J5{  
} -o$QS,  
//负责部分文件的抓取 '}B+r@YCN  
**FileSplitterFetch.java Cjc6d4~  
*/ Gn ~6X-l  
package NetFox; r76
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@ycDCB(D}  
;/r1}tl+3>  
import java.io.*; xKuRh}^K  
import java.net.*; 8~J(](QA  
@zU6t|mhz  
.J)I | '  
public class FileSplitterFetch extends Thread { __|+w<]  
.QZaGw=,z  
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String sURL; //File URL i36eBjT  
long nStartPos; //File Snippet Start Position  SL#0kc0x  
long nEndPos; //File Snippet End Position _"bHe/'CI  
int nThreadID; //Thread's ID &jslyQ#  
boolean bDownOver = false; //Downing is over mID"^NOi#  
boolean bStop = false; //Stop identical 60J;sGW  
FileAccessI fileAccessI = null; //File Access interface H!5\v
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException E\as@pqo\p  
{ YjxF}VI~<  
this.sURL = sURL; 3%E }JU?MM  
this.nStartPos = nStart; +a^nlW9g  
this.nEndPos = nEnd; }o(zj=7  
nThreadID = id; MvK !u  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 PIu1+k.r?  
} !g5
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public void run() p i %<Sy  
{ {^CY..3 A  
while(nStartPos < nEndPos && !bStop) G6/p1xy>o:  
{ |iE50,  
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try{ ==3dEJS  
URL url = new URL(sURL); Tn*9lj4  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); >qS9PX  
httpConnection.setRequestProperty("User-Agent","NetFox"); 8Kg n"M3  
String sProperty = "bytes="+nStartPos+"-"; j|U#)v/  
httpConnection.setRequestProperty("RANGE",sProperty); b
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Utility.log(sProperty);
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InputStream input = httpConnection.getInputStream(); eJxw)zd7  
//logResponseHead(httpConnection); qf!p 9@4F[  
#_6I w`0  
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byte[] b = new byte[1024]; :=u?Fqqws  
int nRead; 6-z%633DL  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) xTj|dza  
{ _ba>19csq%  
nStartPos += fileAccessI.write(b,0,nRead); #gz M|  
//if(nThreadID == 1) 9$cWU_q{  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); [@J/eWB  
} X-6de>=  
F Sw\_[^CQ  
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Utility.log("Thread " + nThreadID + " is over!"); [fAV5U  
bDownOver = true; GFeQ%l`7F  
//nPos = fileAccessI.write (b,0,nRead); Qw-~>d  
} 2%LLSa  
catch(Exception e){e.printStackTrace ();} YB(Q\hT~\;  
} p1Jh0o8  
} ar__ Pf6r  
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B8": 2HrW$  
//打印回应的头信息 9^oKtkoDZ  
public void logResponseHead(HttpURLConnection con) yXSFjcoB  
{ =/s>Q l  
for(int i=1;;i++) s/$?^qtyC  
{ )bS yB29S  
String header=con.getHeaderFieldKey(i); ~Sj9GxTe  
if(header!=null) sDPs G5q<  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); |TS>hwkI  
Utility.log(header+" : "+con.getHeaderField(header)); '[AlhBX  
else w>pq+og&  
break; ED=V8';D  
} XGYbnZ
~   
} RL!Oi|8  
)
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 gbF+WE  
public void splitterStop() L2\#w<d  
{ #M9~L[nFS  
bStop = true; "I3@m%qv  
} $"+djI?E9  
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} \k.{-nh  
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/*

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**FileAccess.java nyQ&f'<  
*//文件访问(定位，写) wPQH(~k:  
package NetFox; cG[l!Z  
import java.io.*; 0)Uce=t`  
8&GBV_`I  
- Ajo9H  
public class FileAccessI implements Serializable{ ] eotc2?u  
jyZ  (RB  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 aS{|uE]  
RandomAccessFile oSavedFile; l3Xfc2~ 2  
long nPos; Sc\*W0m  
@$ne{2J3  
$ `ov4W  
public FileAccessI() throws IOException zd2)M@  
{ pmuvg6@h  
this("",0); ~ksi</s  
} Ka
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|:nn>E}ZA/  
cz >V8  
public FileAccessI(String sName,long nPos) throws IOException /)YNs7gR  
{ 8<X#f !  
oSavedFile = new RandomAccessFile(sName,"rw"); B,?T%  
this.nPos = nPos; %KsEB*'"  
oSavedFile.seek(nPos); m8A#~i .  
} 6eLR2  
%Qmn-uZ  
;D3C>7y  
public synchronized int write(byte[] b,int nStart,int nLen) gwLf'  
{ YmL06<Mh  
int n = -1; NP0\i1P>.?  
try{ T$>WE= Y  
oSavedFile.write(b,nStart,nLen); 9]k @Q_  
n = nLen; h}[-'>{  
} e%svrJ2   
catch(IOException e) \nXtH}9ZF  
{ =$u! 59_dE  
e.printStackTrace (); <CS(c|7  
} l{5IUuUi  
@Xt*Snd  
T. }1/S"m  
return n; I3aNFa}  
} 6/5YjO|a  
nr95YSH  
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} H3z:

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/* m4**~xfC  
**SiteInfoBean.java Z/W:97M  
*/ x3hB5p$q  
package NetFox; .!Oo|m`V@  
R cAwrsd  
CuFSeRe  
public class SiteInfoBean { UbXh,QEG*  
{&cJDqz5=  
pV9IHs}  
private String sSiteURL; //Site's URL &q3"g*q  
private String sFilePath; //Saved File's Path FEW14U'O  
private String sFileName; //Saved File's Name  DGRXd#  
private int nSplitter; //Count of Splited Downloading File fa-IhB1!K  
qB~rQPa  
,kiv>{  
public SiteInfoBean() y`VyQWW  
{//nSplitter的缺省值为5 ),0g~'I~D  
//default value of nSplitter is 5 d?ex,f.  
this("","","",5); gR&Q3jlIV  
} R_ B7EP  
B~6&{7xc%  
P
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 0@[$lv;OS  
{ 8*W#DH!  
sSiteURL= sURL; .I7pA5V{#  
sFilePath = sPath; *T-<|zQ  
sFileName = sName; UvJ}b  
this.nSplitter = nSpiltter; @'w"R/,n-@  
:G [|CPm-  
c?tBi9'Y]  
} q_Q/3rh  
)mg:_K  
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public String getSSiteURL() |N4.u _hM  
{ h`]I
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return sSiteURL; s(5Y  
} ]GMe\n  
n D0K).=Q  
*M[?bk~~  
public void setSSiteURL(String value) 9{'N{  
{ aAZZ8V  
sSiteURL = value; HU1h8E$-  
} n
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;%B(_c  
bk[
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public String getSFilePath() Pj[PIz  
{ wu7Lk3  
return sFilePath; srPWE^&  
} VEH&&@d  
%<)2/|lCd  
<C_jF  
public void setSFilePath(String value) w;;BSJ]+[  
{ |EIng0a  
sFilePath = value; 9/{(%XwX  
} rxVanDb=W  
FTH|9OP
  
1A?W:'N  
public String getSFileName() mf
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{ tGD6AI1"I  
return sFileName; )#EGTRdo  
} g%ndvdb m  
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++bf#qS<8D  
public void setSFileName(String value) v6[!o<@"a  
{ [/,)  
sFileName = value; 8{|8G-Mi  
} 0Be<X  
)s)I2Z+  
6|
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public int getNSplitter() d:_t-ZZo  
{ 0m7Y>0wC6T  
return nSplitter; S(o#K
|)>  
} \(3y7D  
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#Z}Rfk(~  
public void setNSplitter(int nCount) )mI05
 
{ }Q)#[#e  
nSplitter = nCount; ~t@cO.c  
} XpIklL7  
} Km%]1X7T6  
IrR7"`.i  
V8e>l[tH  
/* @y e4q.m  
**Utility.java G[B=>Cy  
*/ V("{)0~O  
package NetFox; d)B@x`  
@*F"Q1 wI  
>L|;|X!m9\  
public class Utility { CWf /H)~  
\(~y?l  
v:EB*3n5  
public Utility() ]O Z5fd  
{ *w$W2I>b7  
w:??h4lt  
IW)()*8;/  
} LnFdhrB@x  
7WZr
SC  
//线程睡眠 B5gj_^  
public static void sleep(int nSecond) LZ\q37UV  
{ }xKP~h'F  
try{ +cWLjPD/}  
Thread.sleep(nSecond); PvR6 z0  
} <z+t,<3D  
catch(Exception e) 7.-V-?i  
{ anuL1fXO  
e.printStackTrace (); &*sP/z  
} 68bQ;Dv  
}
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h~A/y!s  
//日志 *zNYZ#  
public static void log(String sMsg) V @rI`~$  
{ {qDSPo  
System.err.println(sMsg); 9 ^o-EC!_  
} VJ84?b{c W  
y9_V  
~aw.(A?MI  
public static void log(int sMsg) Dw|}9;5:A  
{ ioaU*%  
System.err.println(sMsg); OHv[#xGuV?  
} BK*x] zG$  
} |o,YCzy|5  
SD#]$v  
K*\'.~[6  
/* 909?_v  
**TestMethod.java 6.FY0.i  
*/ MU>k,:[  
package NetFox; "
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< |e,05aM  
p$SX  
public class TestMethod { T _M!<J  
JgG$?n\  
agkA}O  
public TestMethod() 5NBV[EP  
{ ///xx/weblogic60b2_win.exe #XK2Ien)Z  
try{ X$%'  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); nvca."5y  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ?m![Pg%  
SiteFileFetch fileFetch = new SiteFileFetch(bean); PxF<\pu&  
fileFetch.start(); U!T~!C^  
} WJ)z6m]  
catch(Exception e){e.printStackTrace ();} w'L\?pI  
~L]|?d"  
|].pDwgt  
} \Fl+\?~D  
X(!Cfb8+5  
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public static void main(String[] args) u,F nAh?"  
{ 2*rH?dz8E  
new TestMethod(); >O1[:%Z1  
} g$n7CXoT  
} ^F>cp ,x  
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