http断点续传简单实现（java)

/* hp%|n:.G  
**SiteFileFetch.java nDkyo>t.  
*/ %QVX1\>]  
package NetFox; bb$1RLyRL  
import java.io.*; oS/<)>\Gv  
import java.net.*; VZ}^1e  
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1G=1FGvP  
public class SiteFileFetch extends Thread { sn+i[  
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SiteInfoBean siteInfoBean = null; //文件信息Bean hc"+6xc  
long[] nStartPos; //开始位置 H"WkyvqXb  
long[] nEndPos; //结束位置 82YTd(yB
 
FileSplitterFetch[] fileSplitterFetch; //子线程对象 $s/N;E!t  
long nFileLength; //文件长度 9-Ikd>9  
boolean bFirst = true; //是否第一次取文件 0J7[n*~  
boolean bStop = false; //停止标志 4G;+ETp  
File tmpFile; //文件下载的临时信息 f%an<>j^w  
DataOutputStream output; //输出到文件的输出流 G=jdb@V/?  
WT;=K0W6&  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） u!k\W{  
public SiteFileFetch(SiteInfoBean bean) throws IOException S3MMyS8  
{ G{knO?BK  
siteInfoBean = bean; KY!  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); sI@m"A  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ZQD_w#0j  
if(tmpFile.exists ()) }wC pr.@  
{ T3@wNAAU  
bFirst = false; $`i$/FE  
read_nPos(); b~Y
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} fk5!/>X  
else R KFz6t  
{ % rRYT8  
nStartPos = new long[bean.getNSplitter()]; m_W\jz??k  
nEndPos = new long[bean.getNSplitter()]; ;? '`XB!  
} %q;3bfq@N  
8
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} z~L4BY@z  
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public void run() [`Ol&R4k  
{ d8C?m*3J  
//获得文件长度 !?DPI)  
//分割文件 4+:Q"  
//实例FileSplitterFetch );kO27dg  
//启动FileSplitterFetch线程 aG%KiJ7KEN  
//等待子线程返回 ~x)Awdlu  
try{ QjWv?tm  
if(bFirst) 'aBX>M  
{ z[M LMf[c  
nFileLength = getFileSize(); .6z#o{n  
if(nFileLength == -1) U-QK   
{ %ErLL@e  
System.err.println("File Length is not known!"); L Bb&av  
} Cl7IP<.  
else if(nFileLength == -2) 1tDd4r?Y  
{ m>x.4aO1  
System.err.println("File is not access!"); \;&j;"c,W  
} :2^%^3+V  
else =W.b7 6_  
{ fZ`b~ZBwIj  
for(int i=0;i<nStartPos.length;i++) JX7_/P  
{ |qH-^b.F  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Sqed*  
} Lp5LRw  
for(int i=0;i<nEndPos.length-1;i++) |P$tLOrG  
{ lE78Yl]  
nEndPos = nStartPos[i+1]; UA!-YTh  
} AY5%<CWj8  
nEndPos[nEndPos.length-1] = nFileLength; .5p"o-:D  
} }N]|zCEj  
} R3TdQ6j  
7Y&W^]UZ0t  
r,(rWptf4  
//启动子线程 T\:Vu{|  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; rZLTai}`>  
for(int i=0;i<nStartPos.length;i++) |_&vW
\  
{ v,bes[Ik  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), w,SOvbAxX2  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), `{c %d  
nStartPos,nEndPos,i); =5l7{i*`  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); EoD;'+d  
fileSplitterFetch.start(); #~^#%G
 
} y#F( xm+L  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), -8-  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); x~j>Lvw L  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 'H`aQt+  
nEndPos = " + nFileLength); e[$=5
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// fileSplitterFetch[nPos.length-1].start(); 8)s}>:}  
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oS 7q#`  
//等待子线程结束 0j %s H  
//int count = 0; -|\V'  
//是否结束while循环 ;+'x_'a  
boolean breakWhile = false; c~3OK_k  
V2Q2(yvdJ  
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while(!bStop) ]R32dI8N  
{ "-C.gqoB  
write_nPos(); \L>3E#R-Q  
Utility.sleep(500); RZ#b)
l  
breakWhile = true; 5<wIJ5t  

1//d68*"  
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for(int i=0;i<nStartPos.length;i++) ~2@+#1[g8z  
{ LX[<Wh_X(  
if(!fileSplitterFetch.bDownOver) @;_xFL;{g  
{ K'kWL[Ut!  
breakWhile = false; .:A9*,  
break; 8C7$8x]mM  
} -`sK?*[{J  
} :V*c9,>ZO  
if(breakWhile) wa-#C,R\_#  
break; sgu#`@o  
HJ?p,V q5_  
9gVu:o1/  
//count++; v^1_'PAXu  
//if(count>4) k%YvJXL  
// siteStop(); ShbW[*5  
} V]dzKNFi  
lK;|ciq"c7  
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System.err.println("文件下载结束！"); Xb6X'rY  
}
}K1v=k  
catch(Exception e){e.printStackTrace ();} ad+@2-Y  
} P /|
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hg
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//获得文件长度 %"B+;{y(5  
public long getFileSize() L9ECF;)  
{ MKzIY:ug  
int nFileLength = -1; O W`yv  
try{ M6
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URL url = new URL(siteInfoBean.getSSiteURL()); J:Lw
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); d|#sgGM<8  
httpConnection.setRequestProperty("User-Agent","NetFox"); 6yH(u}!.  
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int responseCode=httpConnection.getResponseCode(); q;a"M7  
if(responseCode>=400) YaU)66=u  
{ Ox
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processErrorCode(responseCode); l&#&}3M  
return -2; //-2 represent access is error +LFh}-X{_  
} NrA?^F  
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String sHeader; t M?3oO  
<*k]Aa3y  
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for(int i=1;;i++) ;%wQ
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{ *%'nlAX6%  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); KYBoGCS>  
//Utility.log(in.readLine()); 3"afrA  
sHeader=httpConnection.getHeaderFieldKey(i); d h5%  
if(sHeader!=null) /
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{ q$IgkL  
if(sHeader.equals("Content-Length")) Jd#g"a>zZ  
{ "g}mxPe  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); x[L/d"Wf  
break; >F7v'-*{  
} vU|=" #  
} ]$7dkP  
else 4:m/w!q$  
break; d0ZbusHHb  
} 4'EC(NR7N  
} kq+`.  
catch(IOException e){e.printStackTrace ();} 2smQD8t  
catch(Exception e){e.printStackTrace ();} k6.<zs0  
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Utility.log(nFileLength); EhJpJb[Z  
-aj)
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return nFileLength; fbv%&z  
} \ k&(D*u  
o+-G@16  
>Vp#  
//保存下载信息（文件指针位置） ~t0\Q; @($  
private void write_nPos() 1:{BC2P  
{ =6Z$nc R  
try{ P:Nj;Cxh  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Vm6 0aXm_  
output.writeInt(nStartPos.length); .]gY{_|x  
for(int i=0;i<nStartPos.length;i++) /D@(o`a  
{ N5m+r.<;  
// output.writeLong(nPos); x,LQA0  
output.writeLong(fileSplitterFetch.nStartPos); 0=g~ozEW&  
output.writeLong(fileSplitterFetch.nEndPos); P[q`{TdV  
} `]*BDSvE  
output.close(); 7l+>WB_]  
} d4(!9O.\  
catch(IOException e){e.printStackTrace ();} w+MCOAB  
catch(Exception e){e.printStackTrace ();} w&U>w@H^  
} 4<c#3]  
( q8uB  
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//读取保存的下载信息（文件指针位置） 6,J:sm\  
private void read_nPos() $<c;xDO&t  
{ 1UyQ``v/  
try{ 0J \hku\  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); (}^Qo^Vr  
int nCount = input.readInt(); @-d0~.S  
nStartPos = new long[nCount]; xNLvK:@0p  
nEndPos = new long[nCount]; IgxZ_2hO  
for(int i=0;i<nStartPos.length;i++) O\;R (  
{ 9pY`_lxa>  
nStartPos = input.readLong(); @ckOLtxE>  
nEndPos = input.readLong(); @)h
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} s"jNS1B  
input.close(); T][r'jWQ  
} cx_.+R  
catch(IOException e){e.printStackTrace ();} ccCe@1RI  
catch(Exception e){e.printStackTrace ();} 335\0~;3  
} ]Sl]G6#Iwv  
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private void processErrorCode(int nErrorCode) 4=b{k,kzgA  
{ 97XGJ1HI  
System.err.println("Error Code : " + nErrorCode); Td|x~mZv:  
} P. V #  
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qYi<GI*|@  
//停止文件下载 #"3az8u  
public void siteStop() ,?zIt6Z  
{ -( d,AX  
bStop = true; M?yWFqFt9m  
for(int i=0;i<nStartPos.length;i++) ? FlV<nE"J  
fileSplitterFetch.splitterStop(); h_w_OCC&2  
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oJ<Wh @  
} fD>0  
} _mi(:s(  
//负责部分文件的抓取 fxR}a,a  
**FileSplitterFetch.java $ 2/T]  
*/ BAQ;.N4  
package NetFox; 4t Z. T9d  
Wd0$t   
#!h +K"wX  
import java.io.*; [+j39d.Q  
import java.net.*; pbM"tr_A{  
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public class FileSplitterFetch extends Thread { Xy;!Q`h(  
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NbDfD3 1GK  
String sURL; //File URL G0u3*.  
long nStartPos; //File Snippet Start Position s</llJ$  
long nEndPos; //File Snippet End Position -_>g=a@&  
int nThreadID; //Thread's ID !edgziuO  
boolean bDownOver = false; //Downing is over Sn_zhQxG  
boolean bStop = false; //Stop identical tG{?  
FileAccessI fileAccessI = null; //File Access interface x:Nd>Fb  
:2n(WXFFI  
1.5lJ:[G  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ' YONRha  
{ SdI/  
this.sURL = sURL; N]p|c3D  
this.nStartPos = nStart; <;?&<qMo,P  
this.nEndPos = nEnd; HOb-q|w  
nThreadID = id; UpA{$@  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 JMT?+/Qbu  
} kOe~0xoT@u  
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public void run() `Al[gG?/!  
{ O>![IH(L  
while(nStartPos < nEndPos && !bStop) 0M?nXHA[  
{ vG
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rLzYkZ  
;[_w&"[6a  
try{ )~](qLSl  
URL url = new URL(sURL); ^1%gQ@P  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); M?UlC   
httpConnection.setRequestProperty("User-Agent","NetFox"); OoFQ@zE7%  
String sProperty = "bytes="+nStartPos+"-"; 1qs~[7{C1  
httpConnection.setRequestProperty("RANGE",sProperty); $=97M.E  
Utility.log(sProperty); E"[^^<I  
Wv  
[|sKu#yW  
InputStream input = httpConnection.getInputStream(); b=#3p  
//logResponseHead(httpConnection); \E'Nk$V3  
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byte[] b = new byte[1024]; `R}D@  
int nRead; 3xW;qNj:!l  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) }}GBCXAf_  
{ 'z#{'`$a  
nStartPos += fileAccessI.write(b,0,nRead); (VPT% l6  
//if(nThreadID == 1) Yg;g!~
  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); q5$z:'zE  
} %;.|?gR  
%5_eos&<^)  
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Utility.log("Thread " + nThreadID + " is over!"); ==psPyLF@  
bDownOver = true; i*9l  
//nPos = fileAccessI.write (b,0,nRead); `TkIyGr  
} x*#F|N4~',  
catch(Exception e){e.printStackTrace ();} 1%L* 9>e  
} 6,Q{/  
} %Km_Sy[7']  
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n\2VrUQ)M  
//打印回应的头信息 cLQvzd:h=  
public void logResponseHead(HttpURLConnection con) /~_Cb=7  
{ YkcX#>,  
for(int i=1;;i++) ;3n0 bKDY  
{ }*n(RnCn  
String header=con.getHeaderFieldKey(i); lQ%]](a6  
if(header!=null) c;w~-7Q*|  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); JH~ve  
Utility.log(header+" : "+con.getHeaderField(header)); HrA6wn\O  
else Xu1l6jr_  
break; u.gh04{5  
} *JG?^G"l  
} 6e@ O88=  
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~6'6v8  
public void splitterStop() P,"z  
{ {Izg1N  
bStop = true; xG_ ;F  
} {rWu`QT  
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} b`n+[UCPtn  
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{uO8VL5+Qx  
/* 9p!V?cH#8  
**FileAccess.java n=RAE^[
M  
*//文件访问(定位，写) k=[!{I  
package NetFox; -[#Mx}%  
import java.io.*; vd-`?/,||  
k@5,6s:  
xZ@H{):  
public class FileAccessI implements Serializable{ b?oT|@  
q[]!V0Ek10  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 $JTy`g0>x  
RandomAccessFile oSavedFile; (Jfi 3 m  
long nPos; v&(X&q  
2 G_*Pqc  
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public FileAccessI() throws IOException qH6DZ|  
{ QEM")(  
this("",0); 9AJ!7J#v"  
} gFJ&t^yL  
-e%=Mpq.  
fH
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public FileAccessI(String sName,long nPos) throws IOException t4?g_$>   
{ (0W%YZ!&  
oSavedFile = new RandomAccessFile(sName,"rw"); ,"PwNv  
this.nPos = nPos; iQ-;0<=G  
oSavedFile.seek(nPos); Bh*~I_Ta>  
} Z`"UT#^SI  
,ewg3mYHC&  
%_1~z[Dv  
public synchronized int write(byte[] b,int nStart,int nLen) /-$`GT?l  
{ Fm-W@  
int n = -1; 3h"; 2  
try{ 1X2oz  
oSavedFile.write(b,nStart,nLen); C[rYV
a .  
n = nLen; Y[T;j p(k  
} Ii*v(`2b  
catch(IOException e) )?pin|_x  
{ hzPx8sO  
e.printStackTrace (); 5vYh~|  
} "h7-nwm  
hC]c =$=7  
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return n; .,,?[TI  
} 5%?La`C9[  
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} 5DyN=[b  
c ~YD|l  
^V_acAuS^  
/* V{Idj\~Jh  
**SiteInfoBean.java KN~E9oGs  
*/ |gxU;"2`5~  
package NetFox; Xk]5*C]6<  
X@9_ukdpu  
2k"a%#H8  
public class SiteInfoBean { /~7H<^}  
:c)<B@NqNo  
30>TxL=&  
private String sSiteURL; //Site's URL K;6K!6J:[  
private String sFilePath; //Saved File's Path tb/u@}")  
private String sFileName; //Saved File's Name *&UVr  
private int nSplitter; //Count of Splited Downloading File y%TR2CvT  
Jkm\{;  
 2WE  
public SiteInfoBean() I6y&6g  
{//nSplitter的缺省值为5 yc]ni.Hz  
//default value of nSplitter is 5 0 nWV1)Q0=  
this("","","",5); rxa"ji!)  
} v_c'npC  
![abDT5![  
{,APZ`q|  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) c#"\&~. P  
{ _5 tw1 >  
sSiteURL= sURL; 5B2x# m|8  
sFilePath = sPath; bHS2;K~  
sFileName = sName; K!I]/0L  
this.nSplitter = nSpiltter; `yYgL@Zt  
Oku4EJFJ  
m3_e]v3{o  
} P603P  
FbFUZ^Zj  
=#Vdz=.  
public String getSSiteURL() d*A>P  
{ 1uV_C[:  
return sSiteURL; ,C&h~uRi#f  
} 6^{ hY^Z  
lBG*P>;  
82J0t}
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public void setSSiteURL(String value) '12|:t&7  
{ wmo'Pl  
sSiteURL = value;  QV .A.DK  
} &@+K%qW[e  
gP(-Op  
@/$mZ]|T  
public String getSFilePath() F|P2\SPL  
{ 1v2wP2]|;  
return sFilePath; sgX}`JH?z  
} w,}}mC)\*  
n"FOCcTIs  
g+k6pi*  
public void setSFilePath(String value) ejr"(m(Xe  
{ cWRB=`=qz  
sFilePath = value; !+hX$_RT  
} VpVw:Rh>  
huKz["]z[  
p*npY"}v  
public String getSFileName() YSa:"A  
{ hq,;H40%/  
return sFileName; [tD*\\IA  
} iBo-ANnK9  
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<q[*kr  
public void setSFileName(String value) 'E&K%/d  
{ ~:t2@z4p  
sFileName = value; p\-.DRwT`  
} oC7#6W:@w  
_ZS<zQ'  
t9`NCng 5  
public int getNSplitter() <BU|?T6~  
{ (B$FX<K3  
return nSplitter; *e>:K$r  
} e0$m
u?wd-  
bR8)s{p6  
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public void setNSplitter(int nCount) OT *W]f  
{ .ERO*Tj  
nSplitter = nCount; 2~`dV_  
} ,o}[q92@w  
} Y4714  
&9ZIf#R  
c''O+,L1+  
/* rSJ}qRXwU  
**Utility.java =VY4y]V
 
*/ {VNeh  
package NetFox; ,3n}*"K  
ffB]4  
xK y<o  
public class Utility { A&M/W'$s  
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public Utility() `q@~78`  
{ EV(/@kN2  
A!Yqj~  
eoL)gIM%  
} ttKfZ0  
hN:Z-el  
//线程睡眠 lLDHx3+  
public static void sleep(int nSecond) iIF'!K=q  
{ mY AFruN  
try{ @'rO=(-b  
Thread.sleep(nSecond); % (.PRRI  
} 3PEs$m9e  
catch(Exception e) }GC{~ SZ4  
{ aLq;a  
e.printStackTrace (); 0=5i\*5 p  
} B~ez>/H^  
} 'H9~rq7  
:Aa^afjJw  
//日志 lxz %bC@  
public static void log(String sMsg) e5/_Vga  
{ .o8Gi*PEY  
System.err.println(sMsg); 1k~jVC
2VA  
} 8xv\Zj+  
o{hKt
?  
i:$g1  
public static void log(int sMsg) .)GVb<w  
{ >mV""?r]  
System.err.println(sMsg); SeTU`WLEm  
} y5ExEXa  
} <?g{Rn  
Rq9gtx8,=  
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/* <@=NDUI3*,  
**TestMethod.java C;ye%&g>  
*/ W9D)QIqbvW  
package NetFox; l
m\u(3_$  
19vD(KC<  
Mzd}9x$'J  
public class TestMethod { 2uHp%fv;  
fI|1@e1  
?c+;  
public TestMethod() CMr`n8M  
{ ///xx/weblogic60b2_win.exe B::?  
try{ "osYw\unI  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); dWUu3  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); =3:ltI.'*I  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ~;W%s  
fileFetch.start(); W{h7+X]Y  
} RW)C<g  
catch(Exception e){e.printStackTrace ();} L;  ~=(  
pi{ahuI#_o  
+ ThKqC_  
} -5[GX
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;$i'A&)OC  
)/JC.d#  
public static void main(String[] args) a
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{ 6p@ts`#  
new TestMethod(); %xRS9A4  
} ^n]s}t}csV  
} 9<ayQ*  
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