http断点续传简单实现（java)

/* 0Uk@\[1ox  
**SiteFileFetch.java &UCsBqIY  
*/ klgy;jSEr  
package NetFox; 0$+fkDf  
import java.io.*; G0O#/%%  
import java.net.*; jn >d*9u  
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65h @}9,U  
public class SiteFileFetch extends Thread { {U<xdG  
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SiteInfoBean siteInfoBean = null; //文件信息Bean vx_o(wof  
long[] nStartPos; //开始位置 +YLejjQ  
long[] nEndPos; //结束位置 zA+~7;7E  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 $N:Vo(*  
long nFileLength; //文件长度 N,2s?Y_!  
boolean bFirst = true; //是否第一次取文件 
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boolean bStop = false; //停止标志 )irRO8  
File tmpFile; //文件下载的临时信息 Y HSYu  
DataOutputStream output; //输出到文件的输出流 m-^8W[r+_  
Y)N-V ]5L  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） o&AM2U
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public SiteFileFetch(SiteInfoBean bean) throws IOException 5zFR7/p{  
{ dVB~Smsr  
siteInfoBean = bean; "s!7dKXI"  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); <<=WY_m}  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); #P]#9Ty:  
if(tmpFile.exists ()) D`J6h,=2l/  
{ J_Ltuso  
bFirst = false; #ET/=  
read_nPos(); LK6; ?m  
} A;\7|'4  
else Q#h 9n]5  
{ %AOja+  
nStartPos = new long[bean.getNSplitter()]; I$E.s*B9  
nEndPos = new long[bean.getNSplitter()]; ~%?`
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} ]EwVpvTw  
|-V&O=!^+  
1]
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} `wF8k{Pb  
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public void run() ;nC.fBu  
{ V=fEPM  
//获得文件长度 it]E-^2>  
//分割文件 p!k7C&]E  
//实例FileSplitterFetch b'6-dU%  
//启动FileSplitterFetch线程 5_XV%-wM  
//等待子线程返回 xss`Y,5?  
try{ !mWiYpbU+  
if(bFirst) yG Wnod'
 
{ `
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nFileLength = getFileSize(); f2,jh}4  
if(nFileLength == -1) >pU:Gr  
{ *@d&5  
System.err.println("File Length is not known!"); Y"OG
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} GA7}K:LP'k  
else if(nFileLength == -2) Y0D}g3`  
{ c
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System.err.println("File is not access!"); cZ)}LX  
} DW)2 m;  
else DJgTA]$&  
{ <SI}lQ'i  
for(int i=0;i<nStartPos.length;i++) OKFtl  
{ /-#I_>:8'  
nStartPos = (long)(i*(nFileLength/nStartPos.length));
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} &\apwD  
for(int i=0;i<nEndPos.length-1;i++) /-bO!RTwf  
{ aW!@f[%~F  
nEndPos = nStartPos[i+1]; 
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} dt2$`X18  
nEndPos[nEndPos.length-1] = nFileLength; (@iMLuewK  
} ^"J8r W6[  
} ]E]2o  
1"pw  
i1S>yV^l  
//启动子线程 +3KEzo1=)  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; :1Q!$  m  
for(int i=0;i<nStartPos.length;i++) ChCrL[2  
{ keB&Bjd&  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), UQB"v3Z  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), a33TPoj  
nStartPos,nEndPos,i); _/wV;h~R  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); < yC  
fileSplitterFetch.start(); u|4$+QiD  
} ;j4?>3  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), fu90]upz~  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); X^WrccNX  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", R
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nEndPos = " + nFileLength); 7"8hC
  
// fileSplitterFetch[nPos.length-1].start(); +[5.WC7J  
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qIld;v8w"g  
//等待子线程结束 -WYAN:s  
//int count = 0; !qX_I db\  
//是否结束while循环 B/` !K  
boolean breakWhile = false; i86>]  
?.D3'qv  
=zyC-;r!  
while(!bStop) 5Kkdo!z  
{ n> ^[T[.S  
write_nPos(); <Qxh)@ N  
Utility.sleep(500); H@ t'~ZO
 
breakWhile = true; _6wFba@>/n  
}N*_KzPIa  
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for(int i=0;i<nStartPos.length;i++) gdkwWoN.  
{ Unsogd  
if(!fileSplitterFetch.bDownOver) rL}YLR  
{ 92^w8Z.  
breakWhile = false; -YsLd 9^4  
break; Y+Fljr*  
} _cu:aktf2  
} ij?  
if(breakWhile) IEU^#=n  
break; C:H
oq(  
Zfy
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+"1NC\<
*  
//count++; {l |E:>Q2  
//if(count>4) T8^5=/  
// siteStop(); 23h% < ,  
} 7U"[Gf  
ZcaX'5}!S  
s>^dxF!+  
System.err.println("文件下载结束！"); %JLk$sP9y`  
} ;X?mmv'  
catch(Exception e){e.printStackTrace ();} clk[/'1  
} ,mj@sC>  
~V$|i"  
\|K;-pL  
//获得文件长度 _r2J7&  
public long getFileSize() ai{Sa U  
{ x:QgjK  
int nFileLength = -1; ;$z$@@WC  
try{ P LueVz  
URL url = new URL(siteInfoBean.getSSiteURL()); uV=Qp1~  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); lEV]4 t_H  
httpConnection.setRequestProperty("User-Agent","NetFox"); 9-rNw?7  
0=K9`=5d0  
4n4?4BEn  
int responseCode=httpConnection.getResponseCode(); hiUD]5Kp  
if(responseCode>=400) 8H_l:Z[:i  
{ D_x+
:1(  
processErrorCode(responseCode); 4T=u`3pD7l  
return -2; //-2 represent access is error 6,9o>zT%H  
} ~j<+k4I~  
3"P }n  
Yh>]-SCw  
String sHeader; 1CHeufQ  
`P9XqWr  
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for(int i=1;;i++) 6qp%$>$Vt;  
{ wR^RM(1  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); -e8}Pm "  
//Utility.log(in.readLine()); Hbpqyl%O>  
sHeader=httpConnection.getHeaderFieldKey(i); Qm/u h  
if(sHeader!=null) DoeiW=  
{ 0fYj4`4=n  
if(sHeader.equals("Content-Length")) &Sr
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{ CjiVnWSz<  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); d$ ^ ,bL2p  
break; ?`4+cx}n  
} zSFDUZ]A3  
} phgm0D7
 
else aAB`G3  
break; A7n\h-b  
} CXC`sPY  
} f{FDuIln  
catch(IOException e){e.printStackTrace ();} 8)4P Ll  
catch(Exception e){e.printStackTrace ();} o";Z$tAJkC  
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Utility.log(nFileLength); %%4t~XC#  
%wSj%>&-R  
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return nFileLength; pbU!dOU~e  
} =X.9,$Y  
;dzL}@we  
/jRRf"B  
//保存下载信息（文件指针位置） }|XtypbL  
private void write_nPos() Q^#;
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{ B|&"#Q  
try{ V?=8".GiX  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 9F*+YG!  
output.writeInt(nStartPos.length); ETXZ?\<a5  
for(int i=0;i<nStartPos.length;i++) !Uq^7Mw  
{ @0SC"CqM  
// output.writeLong(nPos); v_nj$1dY6  
output.writeLong(fileSplitterFetch.nStartPos); uNHF'?X  
output.writeLong(fileSplitterFetch.nEndPos); R>(@ZM&  
} 1Y]TA3:  
output.close(); /=gOa\k|p  
} 2^l[(N  
catch(IOException e){e.printStackTrace ();} =hMY2D  
catch(Exception e){e.printStackTrace ();} -
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} ]~E0gsq  
%y%j*B!%  
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//读取保存的下载信息（文件指针位置） ANps1w#TP  
private void read_nPos() nTz6L
VF  
{ rhb@FE)Mc  
try{ ZAXN6h  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 3fh8$A  
int nCount = input.readInt(); #jxe%2'Ot  
nStartPos = new long[nCount]; q2et|QCru  
nEndPos = new long[nCount]; ^)W[l!!<)  
for(int i=0;i<nStartPos.length;i++) |\g5+fv9  
{ a!u rew#  
nStartPos = input.readLong(); j<)9dEM'  
nEndPos = input.readLong(); INyk3`FT  
} )}_a 0bt  
input.close(); XQ~Ke-QW)  
} \} ^E`b  
catch(IOException e){e.printStackTrace ();} pf_mf.  
catch(Exception e){e.printStackTrace ();} T.qNCJmB  
} npNB{J[  
/
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as>L[jyG/  
private void processErrorCode(int nErrorCode) ^J\~XYg{7  
{ txPIG/  
System.err.println("Error Code : " + nErrorCode);  BouTcC  
} FTeu~<KpM  
$O*O/iG  
xQp|;oW;z  
//停止文件下载 ]hbyELs  
public void siteStop() ._+J_ts  
{ B0ndcB-  
bStop = true; QQV~?iW{~  
for(int i=0;i<nStartPos.length;i++) izx#
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fileSplitterFetch.splitterStop(); X 51Yfr  
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T0]*{k(FR  
} xSBc-u#< G  
} 
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//负责部分文件的抓取 -^ C=]Medl  
**FileSplitterFetch.java [V) L  
*/ <bD>m[8,  
package NetFox; EVNY*&p  
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import java.io.*; gL3"Gg3  
import java.net.*; 5efpeu  
$&2UTczp  
j8sH#b7Z  
public class FileSplitterFetch extends Thread { Zw~
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uy}%0vLo  
:,DM*zBVp  
String sURL; //File URL Q pmsOp|  
long nStartPos; //File Snippet Start Position Q"7Gy<  
long nEndPos; //File Snippet End Position (~J^3O]Fo  
int nThreadID; //Thread's ID 4DOK4{4?5  
boolean bDownOver = false; //Downing is over |#*'H*W  
boolean bStop = false; //Stop identical tu5*Qp\  
FileAccessI fileAccessI = null; //File Access interface H~E(JLcU  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException shMSN]S_x  
{ A<B=f<N3gV  
this.sURL = sURL; 7k(Kq5w.  
this.nStartPos = nStart; t&(PN%icD  
this.nEndPos = nEnd; gy;+_'.j  
nThreadID = id; :Pv*,qHE  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 3q?\r` a  
} ?]4>rl}  
o,P.&m{?  
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public void run() =ID 2  
{ >X51$wBL  
while(nStartPos < nEndPos && !bStop) %b^OeWip  
{ MW+b;0U`#  
A3ZY~s#Iv  
YQS5P#  
try{ i>joT><B  
URL url = new URL(sURL); z-c}N
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); N72Yq)(  
httpConnection.setRequestProperty("User-Agent","NetFox"); L=8+_0  
String sProperty = "bytes="+nStartPos+"-"; ?Q72;/$  
httpConnection.setRequestProperty("RANGE",sProperty); i:l<C  
Utility.log(sProperty); ":nQgV\9  
}>[G5[\  
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InputStream input = httpConnection.getInputStream(); 1=]kWp`i  
//logResponseHead(httpConnection); 0Ld@H)  
 <Tot|R;  
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byte[] b = new byte[1024]; ,<Q~b%(
3  
int nRead; W'on$mB5<  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) -D^}S"'  
{ 5
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nStartPos += fileAccessI.write(b,0,nRead); UQ.7>Ug+8s  
//if(nThreadID == 1) ZlojbL@|4  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Eut
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} \t|M-%&)4  
NzW`B^p  
_A~4NW{U7  
Utility.log("Thread " + nThreadID + " is over!"); :(_+7N[KA  
bDownOver = true; X@|&c]]  
//nPos = fileAccessI.write (b,0,nRead); d O~O |Xsb  
} fkSwD(  
catch(Exception e){e.printStackTrace ();} ILic.@st  
} GAc{l=vT'  
} 0W%@gs5d
&  
> MH(0+B*  
E~kG2x{a  
//打印回应的头信息 dHk
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public void logResponseHead(HttpURLConnection con)
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{ {bPV)RL:  
for(int i=1;;i++) HQ9X7[3  
{ W<<9y  
String header=con.getHeaderFieldKey(i); ~RD+.A  
if(header!=null) aSP4a+\*  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); uZi.HG{<)  
Utility.log(header+" : "+con.getHeaderField(header)); W8g'lqc|  
else h},oF!,  
break; p\Lq}tk<  
} {W\T"7H  
} SAY f'[|w  
4R8G&8b  
_pH{yhA  
public void splitterStop() T{}fHfM  
{ &''WRgZ}  
bStop = true; K]xa/G(  
} Cb:gH}j  
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|0z;K:5s
 
} "Y=+Ls(3o(  
>5 b/or  
5IKL#V`3a  
/* 5#E |R  
**FileAccess.java wJlX4cT4YV  
*//文件访问(定位，写) pN&c(=If  
package NetFox; m~'? /!!  
import java.io.*; D.%B$Y;G  
qSx(X!YS  
J# kl 7
 
public class FileAccessI implements Serializable{ vJ`.iRU|  
;<Km3  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 {5|(
"0[F  
RandomAccessFile oSavedFile; |([R'Orm  
long nPos; /1`cRyS  
}!TL2er_  
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public FileAccessI() throws IOException z5]bia,  
{ *{o UWt  
this("",0); ,pBh`av  
} T$=4O9G  
Q7bq  
pA4*bO+  
public FileAccessI(String sName,long nPos) throws IOException ]h9!ei [  
{ QjPj[c  
oSavedFile = new RandomAccessFile(sName,"rw"); $t-n'Qh^2  
this.nPos = nPos; \b*X:3g*  
oSavedFile.seek(nPos); ueG|*[  
} 26n^Dy>}  
UMN*]_'+;b  
(.3'=n|kE  
public synchronized int write(byte[] b,int nStart,int nLen) s4H2/E
C  
{ '!1$9o^$  
int n = -1; [/RM=4Nh5  
try{ bq
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oSavedFile.write(b,nStart,nLen); l?*r5[O>n  
n = nLen; ZlKw_Sq:  
} W9zE{)Sc~  
catch(IOException e) iK_c.b  
{ 5y4u5Tm-%  
e.printStackTrace (); _;RVe"tR#  
} {I{:GcS  
$ex!!rqN|  
{0YAzZ7  
return n; N{d@^Yj  
} 6*@yE  
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} :1)DqoAJ  
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/* as"N=\N  
**SiteInfoBean.java /\Q*MLwD  
*/ =wq;@'U  
package NetFox; r(2R<A  
'PWQnt
_U  
s4T}Bsr  
public class SiteInfoBean { =sOo:s
 
&GWkq>  
v$w++3H  
private String sSiteURL; //Site's URL eUO9a~<  
private String sFilePath; //Saved File's Path Z%gx%$  
private String sFileName; //Saved File's Name >P. 'CU  
private int nSplitter; //Count of Splited Downloading File ~9$X3.+  
o'%eI  
}PeZO!K  
public SiteInfoBean() ,,=apyr#&  
{//nSplitter的缺省值为5 sP$Ks#/  
//default value of nSplitter is 5 "t(wG{RxY  
this("","","",5); 2}t&iG|0/  
} gd^Js1Z  
{b!7 .Cd=  
qS8B##x+=  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ZYtiMBJ  
{ DHfB@/q#  
sSiteURL= sURL; 7uI#L}y  
sFilePath = sPath; x|~zHFm6  
sFileName = sName; $GF]/;\m  
this.nSplitter = nSpiltter; 5@u~3jPd  
^O%9yEo
  
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} XY+y}D %  
X,v4d~>]  
msk/p>{O  
public String getSSiteURL() $->d!  
{ Q1tpC
T  
return sSiteURL; 6/mF2&&g  
} rj
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s'_,:R\VM>  
public void setSSiteURL(String value) ms~8QL  
{ )fh0&Y; R  
sSiteURL = value; et$uP  
} S]2 {ZDP  
\3PE+$  
cBEHH4U  
public String getSFilePath() t;#Gmo  
{ zX5G;,_  
return sFilePath; fnH3CE  
} #o[\Dwu  
Dl;d33  
KAb(NZK  
public void setSFilePath(String value) ,{<p  
{ F,v7ifo#f  
sFilePath = value; OV5e#AOy)  
} ESDB[ O+`x  
:):zNn_>`  
VO`"<  
public String getSFileName() bsO@2NP'  
{ 8sw,k   
return sFileName; HcJE0-"  
} l C\E  
mtw9AoO  
g"y?nF.&F  
public void setSFileName(String value) BXTN>d27  
{ +Z+ExS<#z  
sFileName = value; 8B@JFpg^  
} #@_1f
E  
(K!4Kp^m  
SFO&=P:U  
public int getNSplitter() D<nxr~pQ  
{ !A[S6-18%-  
return nSplitter; c#\-%h  
} ac6*v49  
~Fx&)kegTo  
iVeQ]k(u  
public void setNSplitter(int nCount) ="B n=>  
{ .5g}rxO8  
nSplitter = nCount; Kpg:yrc['  
} oBw}hH,hp  
} n>llSK  
+"L$ed(=nJ  
"=A|K~b  
/* B| Q6!  
**Utility.java rl|Q)A{  
*/ ~t9Mh^gij  
package NetFox;  ? ICDIn  
/J;]u3e|  
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public class Utility { fq Y1ggL  
N5\{yV21",  
#Wx=v$"  
public Utility() OROqT~6G  
{ ylkqhs&  
d;g-3Pf  
(9z|a,  
}  ^Fp=y
,D  
,o)4p\nV  
//线程睡眠 VR v02m5  
public static void sleep(int nSecond) *8206[y  
{ KW>VOW<.  
try{ "%kGRHq  
Thread.sleep(nSecond); c *1S}us  
} RHXvee55  
catch(Exception e) Dqr9Vv  
{ 6UI>
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e.printStackTrace (); B"[{]GP BY  
} bm6hZA|  
} F '#^`G9  
` @>ZGL:  
//日志 xA9V$#d|  
public static void log(String sMsg) lWlUWhLnP  
{ jZ/+~{<  
System.err.println(sMsg); 0s!N@ ,T  
} ux&:Rw\  
) MBS  
"V
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public static void log(int sMsg) MHNe>C-!q  
{ t 2G1[j!  
System.err.println(sMsg); u#VweXyU  
} 8GW ut=D  
} SW=aHM  
*2#FRA#q  
6puVw-X  
/* z'e1"Y.  
**TestMethod.java O3&
|}:<  
*/ <O bHf`Q  
package NetFox; M1gP R  
X{'wWWZC  
9;pzzZ  
public class TestMethod { ^Yr|K  
IrUi Eq  
{DS\!0T-X  
public TestMethod() dh?S[|='  
{ ///xx/weblogic60b2_win.exe XqX I(q^  
try{ s+N^PX3  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); dv[\.T`LY  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); J5-rp|  
SiteFileFetch fileFetch = new SiteFileFetch(bean); .f+9 A>  
fileFetch.start(); RSFJu\0}N  
} jDJ.  
catch(Exception e){e.printStackTrace ();} Hz5;Ruw'  
B%y! aQep  
>eu `!8  
} 8k%H[Smn:  
Yd.027  
X-v~o/r7  
public static void main(String[] args) UCn
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{ 5{HtJ?sKc5  
new TestMethod(); 6s&qZ+v-  
} { $X X  
} Jtpa@!M  
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