http断点续传简单实现（java)

/* *%6NuZ  
**SiteFileFetch.java iY_E"$}P  
*/ q3Tp/M.  
package NetFox; <~D-ew^BU  
import java.io.*; $w%n\t>B  
import java.net.*; 1j4(/
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public class SiteFileFetch extends Thread { ^6c=[N$aW  
?7n(6kmj4Q  
(?[^##03MN  
SiteInfoBean siteInfoBean = null; //文件信息Bean E6 glR  
long[] nStartPos; //开始位置 \l$gcFXb  
long[] nEndPos; //结束位置 x.J% c[Q8  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 'a1%`rzm  
long nFileLength; //文件长度 @-9u;aL  
boolean bFirst = true; //是否第一次取文件 HH`G/(a  
boolean bStop = false; //停止标志 JrZ"AId2  
File tmpFile; //文件下载的临时信息 >U?U;i  
DataOutputStream output; //输出到文件的输出流 L&*/s&>b  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） [ QHSCF5  
public SiteFileFetch(SiteInfoBean bean) throws IOException %#g9d  
{ 9#C hn~ \  
siteInfoBean = bean; LY>-kz]  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 8~q%H1[I\N  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ;}/@ar7s3  
if(tmpFile.exists ()) R> r@[$z+  
{ vbXZZ  
bFirst = false; _@-D/g  
read_nPos(); IG}`~% Z  
} KB3zQJY  
else 0H<&*U_V  
{ qQzf&"  
nStartPos = new long[bean.getNSplitter()]; "otks\I<  
nEndPos = new long[bean.getNSplitter()]; gA`x-`  
} qhNY<  
7*D*nY4+  
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*cNqgw#\qL  
} eJh4hp;x  
_4H}OGZI  
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public void run()  3)5Gzn  
{ 6L`{oSX!  
//获得文件长度 wTT_jyH)  
//分割文件 g`(' k5=  
//实例FileSplitterFetch =SY5E{`4p  
//启动FileSplitterFetch线程 aN\psg  
//等待子线程返回 yW3X<  
try{ X[F<sxw  
if(bFirst) XI>|"*-l  
{ 
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nFileLength = getFileSize(); 2d%j6D  
if(nFileLength == -1) IIn0w2:i  
{ .Fdqn?c|+  
System.err.println("File Length is not known!"); Q"2t:  
} F.nJXZnJ  
else if(nFileLength == -2) UD0via  
{ [#}A]1N  
System.err.println("File is not access!"); }4 p3m]  
} .Vy*p")"  
else Y;JPr  
{ }YPW@g  
for(int i=0;i<nStartPos.length;i++) fWr6f`de  
{ }=d]ke9_  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); J?Y1G<&  
} t")+L{  
for(int i=0;i<nEndPos.length-1;i++) %&D,|Yl6  
{ ?2#!63[Kg  
nEndPos = nStartPos[i+1]; h}vzZZ2,  
} pWU3
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nEndPos[nEndPos.length-1] = nFileLength; UIpW#t  
} je9eJUKE  
} q?Jd.r5*  
kPh;SCr{  
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//启动子线程 V
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 2!6+>nvO  
for(int i=0;i<nStartPos.length;i++) =N_7DT  
{ FW?zJ  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ,34|_  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), l~f>ve|  
nStartPos,nEndPos,i); jGM+  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); bu;3Ib3\  
fileSplitterFetch.start(); $~#N1 
 
} 5kX#qT=  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), y;0k |C
 
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); /3MTutM|<X  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", zjyj,jP  
nEndPos = " + nFileLength); 6]GEn=t  
// fileSplitterFetch[nPos.length-1].start(); 6usy0g D  
@B<B#  
A5d(L4Q]a(  
//等待子线程结束 Hh/Z4`&yi  
//int count = 0; =y5~7&9'  
//是否结束while循环 P)7_RE*gY  
boolean breakWhile = false; IW48Sg  
a$Lry?pb  
C'iJFfgR  
while(!bStop) M<f=xY2$v  
{ =Mg/m'QI  
write_nPos(); HA +EuQE"  
Utility.sleep(500); hq5=>p  
breakWhile = true; aFI?^"L  
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for(int i=0;i<nStartPos.length;i++) ?[[K6v}q{  
{ %h"+J  
if(!fileSplitterFetch.bDownOver) 9Y9pKTU  
{ oB3,"zY  
breakWhile = false; Ek!$Ary  
break; 2>s@2=Aq  
} myp}DI(  
} Y,v8eOo45S  
if(breakWhile) kg2?IL  
break; ?}QHEk:H  
}m?1IU%q  
bLx70$  
//count++; GN36:>VWb  
//if(count>4) OG#7Va  
// siteStop(); [zO
   
} 3@k;"pFa<  
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91oIxW  
System.err.println("文件下载结束！"); =4RBHe
8`  
} F",S}cK*MH  
catch(Exception e){e.printStackTrace ();} <h_lc}o/  
} ;pU#3e+P8  
L{>XT
 
]rEFWA  
//获得文件长度 gE,i
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public long getFileSize() R5QSf+/T4  
{ 48.2_H<  
int nFileLength = -1; D`r^2(WW  
try{ GHQa{@m2V  
URL url = new URL(siteInfoBean.getSSiteURL()); G0sg\]  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); *+p9u 1B5  
httpConnection.setRequestProperty("User-Agent","NetFox"); O,Xf.O1c  
AT^?PD_  
*iSsGb\M%  
int responseCode=httpConnection.getResponseCode(); _ ?f~UvK  
if(responseCode>=400) K5x&:z  
{ PI7M3\z  
processErrorCode(responseCode); ojO<sT:by  
return -2; //-2 represent access is error 6&% c  
} (rcH\   
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F+vgkqs@9  
String sHeader; w'q}aQS  
)W&H{2No  
2Y&QJon)  
for(int i=1;;i++) NQq$0<7.=W  
{ B7qm;(?X&  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); kV7c\|N9  
//Utility.log(in.readLine()); <C\snB  
sHeader=httpConnection.getHeaderFieldKey(i); I:s#,!>  
if(sHeader!=null) 6xSdA;<+]  
{ pg69mKZ$  
if(sHeader.equals("Content-Length")) 9)p VDS  
{ u\zRWX  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); VsOn j~@  
break; e:IUO1#  
} yG?,8!/]  
} \H+/D &M  
else Ip]-OVg  
break; S?nXpYr  
} EBS04]5ul  
} \R45#. P6X  
catch(IOException e){e.printStackTrace ();} L.bR\fE   
catch(Exception e){e.printStackTrace ();} M xUj7ae  
%-?HC
jT  
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Utility.log(nFileLength); <#w0=W?  
O3#4B!J$E  
c[@-&o`  
return nFileLength; +_uT1PsBY  
} JB(~O`  
A?8f 6  
XoM+"R"  
//保存下载信息（文件指针位置） %^xY7!{  
private void write_nPos() F*hOa|7/  
{ ZRO   
try{ 7Zp'}Om<I  
output = new DataOutputStream(new FileOutputStream(tmpFile)); \I; lgz2  
output.writeInt(nStartPos.length); 92+LY]jS  
for(int i=0;i<nStartPos.length;i++) ?:OL8&0  
{ ZLe@O~f;%  
// output.writeLong(nPos); hdtb.u~  
output.writeLong(fileSplitterFetch.nStartPos); n= yT%V.l  
output.writeLong(fileSplitterFetch.nEndPos); ;1}~(I#Y  
} qsX
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output.close(); jdV E/5  
} WlU^+ctS  
catch(IOException e){e.printStackTrace ();} b Mi,z3z  
catch(Exception e){e.printStackTrace ();} Iz^~=yV)  
} vMK
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2'tZ9mK  
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//读取保存的下载信息（文件指针位置） s%"3F<\  
private void read_nPos() #\1;d8h  
{ 49&p~g  
try{ : 'M$:ZJ  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); QkUq%}_0  
int nCount = input.readInt(); NxVqV5'  
nStartPos = new long[nCount]; l'T3RC,\  
nEndPos = new long[nCount]; .r+u pY  
for(int i=0;i<nStartPos.length;i++) !'(bwbd  
{ Epsc2TuH7  
nStartPos = input.readLong(); s2)a8<  
nEndPos = input.readLong(); _7?o/Q?F%  
} *[@lp7  
input.close(); D%kY  
} P31}O2 Nh  
catch(IOException e){e.printStackTrace ();} Q+gd|^Vc9  
catch(Exception e){e.printStackTrace ();} fdGls`H  
} U
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private void processErrorCode(int nErrorCode) p't>'
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{ l'HrU 1_7Y  
System.err.println("Error Code : " + nErrorCode); gJ cf~@s  
} }5-^:}gL
 
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//停止文件下载 ^yg`U(  
public void siteStop() i>i@r ;:|  
{ 'S\YNLqQ  
bStop = true; @x?7J@:  
for(int i=0;i<nStartPos.length;i++) #rM/  
fileSplitterFetch.splitterStop(); hu.c&Q>  
_x_om#~n  
EaGh`*"w(7  
} c*$&MCh  
}  bz'V
50  
//负责部分文件的抓取 =z^v)=uhp  
**FileSplitterFetch.java G\&4_MS  
*/ i]!CH2\  
package NetFox; UbKdB  
8?!=/Sc  
oUXu;@l  
import java.io.*; -Wc'k 2oU  
import java.net.*; AGkk|`  
5CH9m[S
 
#jn6DL@[{  
public class FileSplitterFetch extends Thread { Lw<?e;  
]}H;`H  
4
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String sURL; //File URL <&E3QeK  
long nStartPos; //File Snippet Start Position H/'tSb  
long nEndPos; //File Snippet End Position ,\zp&P"p  
int nThreadID; //Thread's ID +"rZ<i  
boolean bDownOver = false; //Downing is over LM}0QL m?  
boolean bStop = false; //Stop identical *&{M,  
FileAccessI fileAccessI = null; //File Access interface {
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException zk= 3L} C  
{ T<kyxbjR  
this.sURL = sURL; JTB
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this.nStartPos = nStart; e8O[xM  
this.nEndPos = nEnd; m,',luQ  
nThreadID = id; j/_@~MJBt  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 =FUORj\O  
} i{TErJ{}e  
I@~hz%'  
s,>1n0a  
public void run() Z'p7I}-qr  
{ LyRto  
while(nStartPos < nEndPos && !bStop) ?LAKH$t  
{ 7bOL,S  
;hU56lfZ)X  
"MZj}}l  
try{ zbn0)JO  
URL url = new URL(sURL); !^BXai/  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); L9[? qFp  
httpConnection.setRequestProperty("User-Agent","NetFox"); 95jJ"4a+  
String sProperty = "bytes="+nStartPos+"-"; kuq3QW<  
httpConnection.setRequestProperty("RANGE",sProperty); o!EPF-:  
Utility.log(sProperty); Qa~dd{?  
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.6S]\dp7~  
InputStream input = httpConnection.getInputStream(); +Z[(s!  
//logResponseHead(httpConnection); /~*U'.V  
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byte[] b = new byte[1024]; f!2`N  
int nRead; w A<JJ_R  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) L/9f"%kZ  
{ uV?[eiezD0  
nStartPos += fileAccessI.write(b,0,nRead); R06q~>  
//if(nThreadID == 1) sXxF5&AF0  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); OO5k_J  
}
@*jd.a`  
`~Nd4EA)2  
=;Gy"F1 dp  
Utility.log("Thread " + nThreadID + " is over!"); "pTyQT9P  
bDownOver = true; oW3{&vfz  
//nPos = fileAccessI.write (b,0,nRead); 9NvV{WI-1  
} 4jE
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catch(Exception e){e.printStackTrace ();} j&)"a,f  
} 6KP"F[8I  
} 6-C9[[g<  
0]3%BgZ(a8  
n| =k9z<y8  
//打印回应的头信息 OV ~|@{6T  
public void logResponseHead(HttpURLConnection con) i~ D,  
{ @(2DfrC  
for(int i=1;;i++) fwB+f`w`  
{  13(JW  
String header=con.getHeaderFieldKey(i); >i=^Mh-bm  
if(header!=null) oyV@BHJO@  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); xgP/BK2"  
Utility.log(header+" : "+con.getHeaderField(header)); 44axOk!G[/  
else TIlBT{A<  
break; b?`8-g  
} <*u[<  
} &scHyt  
Qk?;nF  
#7K&x.w$  
public void splitterStop() !Tuc#yFw  
{ gf2<dEff  
bStop = true; ZVu&q{s,  
} .nX+
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* Zb-
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} P_)h8-!+ $  
}|>mR];  
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/* (.Yt| "j  
**FileAccess.java Q.:SIBP  
*//文件访问(定位，写) Yy]^_,r  
package NetFox; Fa78y
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import java.io.*; #MYhKySku  
t.B%7e  
+Mth+qgw  
public class FileAccessI implements Serializable{ !l1UpJp  
v~i/e+.h>y  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 hQ`g B.DR  
RandomAccessFile oSavedFile; M;*f(JY$  
long nPos; {2?o:  
qv|geBW  
7N0V`&}T  
public FileAccessI() throws IOException .} <$2.  
{  J5PXmL  
this("",0);
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} a!YpSFr  
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<}x_F)E[t  
public FileAccessI(String sName,long nPos) throws IOException eglcf z%  
{ A+i|zo5p=k  
oSavedFile = new RandomAccessFile(sName,"rw"); :/'2@M  
this.nPos = nPos; 3n-~+2l  
oSavedFile.seek(nPos); 9fR`un)f}  
} y\7 -!  
vL~nJv  
- `^594  
public synchronized int write(byte[] b,int nStart,int nLen) "e<Z$"7i  
{ J*s!(J |Q  
int n = -1; V;$ME4B\{  
try{ $,R QA^gxW  
oSavedFile.write(b,nStart,nLen); 6rlafISvO  
n = nLen; h3y0bV[g=  
} FWpcWmS`s  
catch(IOException e) m":lKXpQ  
{ Zhb)n
 
e.printStackTrace (); F8{"Rk}  
} :[f2iZ"  
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return n; A?I/[zkc  
} ,YzrqVY  
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} _(=[d  
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/* --*Jv"/0  
**SiteInfoBean.java t,|`#
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*/ _kR);\V.8  
package NetFox; yxq+<A4,a  
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d%tF~|#A%  
public class SiteInfoBean { K^0cL%dB  
KICy! "af  
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private String sSiteURL; //Site's URL tHgn-Dhzr  
private String sFilePath; //Saved File's Path ge*(w{|x  
private String sFileName; //Saved File's Name +RLHe]9&  
private int nSplitter; //Count of Splited Downloading File \[</|]'[  
=ZdP0l+V=k  
Sb@:ercC,  
public SiteInfoBean() xW92ZuzSH  
{//nSplitter的缺省值为5 ?2h)w=dO
 
//default value of nSplitter is 5 D=*3Xd  
this("","","",5); /~`4a
  
} [7d>c  
26n+v(re  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) @64PdM!L  
{ 20glz(  
sSiteURL= sURL; t# cm|  
sFilePath = sPath; .ET@J`"M  
sFileName = sName; $kPC"!X\  
this.nSplitter = nSpiltter; >|h$d:~n  
8BP.VxX  
Ak(_![Q:q\  
} .{,
PC  
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public String getSSiteURL() p'PHBb8I  
{ aH6{_eY  
return sSiteURL; ]ADj9  
} 9I3vW]0x[  
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public void setSSiteURL(String value) #
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{ WDznhMo  
sSiteURL = value; b[}f]pB@n  
} 1
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R%7* )3$&r  
9a_B   
public String getSFilePath() # `}(x;ge  
{ Vgzw['L}  
return sFilePath; M=vRy|TL  
} IK#W80y  
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(J!FW(Ma|=  
public void setSFilePath(String value) Mf [v7\  
{ '9O4$s1  
sFilePath = value; uCX+Lw+As  
} Skm$:`u;  
HoA[UT  
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public String getSFileName() >kK!/#ZA  
{ Co`O{|NS}!  
return sFileName; VK/@jrL+  
} GTvp)^h  
]`[r=cG  
RZwjc<T  
public void setSFileName(String value) $:|z{p  
{ ldEZ_g^  
sFileName = value; C?IvXPlV  
} 8=XfwwWHy<  
AawK/tfs  
 U~%V;*|4  
public int getNSplitter() BK,h$z7#6  
{ T)QZ9a  
return nSplitter; 0UV5}/2rP  
} JY$B%R4;]  
/`d|W$vN  
ARcPHV<(2  
public void setNSplitter(int nCount) A\{dq:  
{ L`$m<9w'  
nSplitter = nCount; J$Huzs#  
} pVuJ4+`  
} }d<x
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=  
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/* wW5:p]<Y  
**Utility.java AGxtmBB;  
*/ B.:DW3  
package NetFox; dy>iIc>  
RL0#WBR  
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public class Utility { P<Wtv;Z1Z  
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public Utility() ohI>\  
{ eVRFb#EU0e  
-K+" :kiS  
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} @y)'h]d  
r3OTU$t?  
//线程睡眠 'g3!SdaLF  
public static void sleep(int nSecond) FbvwzZ  
{ S1_X@[t  
try{ v=-8} S  
Thread.sleep(nSecond); |
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} -Oj}PGj$e\  
catch(Exception e) #Y)Gos  
{ Z^Y_+)
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e.printStackTrace (); +4[L_  
} v };r  
} S4n~wo  
%}t<,ex(yO  
//日志 -}2'P)Xp  
public static void log(String sMsg) f7y a0%N  
{ 0RaE!4)!;  
System.err.println(sMsg); dE0 `tX  
} Oa[G #  
>Ln/)j  
?]JTrv"zp  
public static void log(int sMsg) [^iQE  
{ 6\8 lx|w  
System.err.println(sMsg); s)?=4zJ  
} J;?#Zt]`L  
} SV-M8Im73z  
QG~4<zy  
egOZ.oV  
/* H;#3S<  
**TestMethod.java =(!&8U9  
*/ XYBvM]  
package NetFox; jzRfD3_s  
fgmu*\x<  
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public class TestMethod { /h)_Q;35S;  
p i;,?p-  
Idq&0<I  
public TestMethod() BhO*Pfs  
{ ///xx/weblogic60b2_win.exe 80i-)a\n  
try{ #>I*c_-  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ~Ibq,9i  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); )qgcz<p?W  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 0?]Y^:  
fileFetch.start(); $L~?!u&N  
} J>H$4t#HX  
catch(Exception e){e.printStackTrace ();} i{#5=np H  
^jY'Hj.Bs  
RnvPqNs  
} oCl $ 0x  
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.@#GNZe  
public static void main(String[] args) %Tc P[<  
{ [M:ag_rm+f  
new TestMethod(); `y1nex-0  
} jFa
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} \Lp|S:u  
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