http断点续传简单实现（java)

/* r%9Sx:F  
**SiteFileFetch.java IM/\t!*7  
*/ K~>kruO";  
package NetFox; BKEB,K=K@  
import java.io.*; 5EUkp6Y  
import java.net.*; W| p?KJk)  
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public class SiteFileFetch extends Thread { ![V- e  
@:I/lg=Qd  
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SiteInfoBean siteInfoBean = null; //文件信息Bean HPQ,tlp6j  
long[] nStartPos; //开始位置 @\R)k(F  
long[] nEndPos; //结束位置 ^-_!:7TH]  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 (XH)1 -Z!  
long nFileLength; //文件长度 f@mM&e=f  
boolean bFirst = true; //是否第一次取文件 2srz) xEe  
boolean bStop = false; //停止标志 );[`rXH_  
File tmpFile; //文件下载的临时信息 K\q/JuDfc  
DataOutputStream output; //输出到文件的输出流 tWFJ
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ^ytd~iK8  
public SiteFileFetch(SiteInfoBean bean) throws IOException +}Pa/8ybJ  
{ wkGF&U  
siteInfoBean = bean; n_<]9  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); DxBt83e  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); &}uO ]0bR  
if(tmpFile.exists ()) pK`rm"6G  
{ 9[!
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bFirst = false; *)1,W+A5L  
read_nPos(); {IVqV6:  
} b/EvcN8 }  
else )+G(4eIT  
{ Q7\Ax0  
nStartPos = new long[bean.getNSplitter()]; jDoWSYu4tY  
nEndPos = new long[bean.getNSplitter()]; %WNy=V9txp  
} oKac~}_KL  
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} lVdExR>H  
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public void run() vC7sJIch2<  
{ ZttL*KK  
//获得文件长度 _W+TZa@_  
//分割文件 rW^&8E[  
//实例FileSplitterFetch ec=C7M |  
//启动FileSplitterFetch线程 I2dt#  
//等待子线程返回  ,Y!)V  
try{ 'K1w.hC<  
if(bFirst) =aCv Xa&,  
{ aE"t['  
nFileLength = getFileSize(); Wac8x%J  
if(nFileLength == -1) 2g$Wv :E3  
{ gLH(Wr~(a  
System.err.println("File Length is not known!"); NJp;t[v.^  
} t^'1Ebg  
else if(nFileLength == -2) DM&"oa50  
{ #FcYJH  
System.err.println("File is not access!"); CeQcnJU  
} X DX_c@U  
else ,'j5tU?c  
{ ;@L#0  
for(int i=0;i<nStartPos.length;i++) ObCwWj^qO  
{ %>.v[d1c  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); bQ)r8[o!  
} "@n$(-.  
for(int i=0;i<nEndPos.length-1;i++) qH ~usgqB7  
{ bchhokH
  
nEndPos = nStartPos[i+1]; Di6:r3sEO  
} QUNsS9  
nEndPos[nEndPos.length-1] = nFileLength; Nl+2m4  
} <L-L}\-I"  
} pmS=$z;I  
n'gfB]H[  
?`r/_EKNv  
//启动子线程 ^vPa{+N  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; f6XWA_[i@  
for(int i=0;i<nStartPos.length;i++) uO6_lOT9n  
{ S8y4 p0mV  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), im'0^  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Ov9.qNT  
nStartPos,nEndPos,i); NF.SGga  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); "*
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fileSplitterFetch.start(); $=bN=hE  
} pUmB h  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), yE7pCgXt  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Np<Aak  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ^Z!W3q Q  
nEndPos = " + nFileLength); I/tz
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// fileSplitterFetch[nPos.length-1].start(); jsR1jou6  
\Q6Ip@?  
W1
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//等待子线程结束 (|x->a  
//int count = 0; DW-LkgfA  
//是否结束while循环 ,QQ:
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boolean breakWhile = false; *
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2Zm*f2$xM  
fZZ!kea[  
while(!bStop) E'ZWSpP  
{ ~ce.&C7cR  
write_nPos(); p|((r?{  
Utility.sleep(500); =4[zt^WX"  
breakWhile = true; O[]+v  
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1pn167IQL  
for(int i=0;i<nStartPos.length;i++) .D)}MyKnu  
{ 1>2397  
if(!fileSplitterFetch.bDownOver) JUE>g8\b  
{ uPqPoI>N!  
breakWhile = false; w+}dm^X  
break; 'i,<j s3\f  
} uYl ?Q  
} My ^pQ]@  
if(breakWhile) ^v},Sa/ot]  
break; z}&<DYD  
eQc!@*:8U  
Frml'Vfq7  
//count++; N*
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//if(count>4) ^;2L`U@5  
// siteStop(); }$o%^"[  
} v!x[1[  
-or9!:8  
R%Z} JR.  
System.err.println("文件下载结束！"); Fg~,1[8w<  
} kA3kh`l  
catch(Exception e){e.printStackTrace ();} O$$N{  
} '!0CwZ 7  
jIl-}/2  
(=X16}n:>  
//获得文件长度 -P?} qy^j(  
public long getFileSize() Z+}SM]m  
{ +vuW9  
int nFileLength = -1; yT>T Vq/e  
try{ ;?cUF78#  
URL url = new URL(siteInfoBean.getSSiteURL()); nQ+{1 C  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); MT*b+&1e  
httpConnection.setRequestProperty("User-Agent","NetFox"); 48DsRy  
k X-AC5]  
k >MgrtJI  
int responseCode=httpConnection.getResponseCode(); H!A^ MI  
if(responseCode>=400) V>%%2"
&C  
{ vQh'C.  
processErrorCode(responseCode); X6;aF;"5  
return -2; //-2 represent access is error Y~CS2%j  
} EKt-C_)U  
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]gEfm
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String sHeader; zbnQ
CLs  
'FVT"M~  
<L`R!}  
for(int i=1;;i++) OJK/>  
{ +VeLd+Q}  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); crT[;w  
//Utility.log(in.readLine()); qm '$R3g  
sHeader=httpConnection.getHeaderFieldKey(i); p?`N<ykF<  
if(sHeader!=null) ,Q:dAe[ZsX  
{ _#+9)*A  
if(sHeader.equals("Content-Length"))
.{}t[U  
{ 2rH6ap  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); |N
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break; 3o?Lz7L  
} "6}+|!"$  
} >5j/4Ly  
else (-#{qkA  
break; +`+a9+
=  
} D3Mce|t^  
} aT0 y  
catch(IOException e){e.printStackTrace ();} k"U4E J{  
catch(Exception e){e.printStackTrace ();} 3ZVfZf  
;~K($_#H  
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Utility.log(nFileLength); 3_-#
 
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}_;nln?t(  
return nFileLength; N.<hZ\].=
 
} r~;N(CG  
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//保存下载信息（文件指针位置） +!<`$+W
 
private void write_nPos() W)_B(;$]  
{ k9,"`dk@  
try{ Y}6)jzBV  
output = new DataOutputStream(new FileOutputStream(tmpFile)); UvI!e4_  
output.writeInt(nStartPos.length); aZ^lI 6@+4  
for(int i=0;i<nStartPos.length;i++) ^>"?!lv  
{ :b=0_<G
 
// output.writeLong(nPos); bcZonS  
output.writeLong(fileSplitterFetch.nStartPos); 1
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output.writeLong(fileSplitterFetch.nEndPos); Ob+&!XTp?0  
} 9f@)
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output.close(); 0(kp>%mbB  
} /?GBp[(0  
catch(IOException e){e.printStackTrace ();} vZxy9Wmc
 
catch(Exception e){e.printStackTrace ();} 0jmlsC>  
} ?m!F
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1-n
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//读取保存的下载信息（文件指针位置） +~@Y#>+./l  
private void read_nPos() l\5NuCgRY  
{ IlrmXSr  
try{ ' 4"L;){:L  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); O^GXFz^  
int nCount = input.readInt(); 7'I
7  
nStartPos = new long[nCount]; 7jPmI  
nEndPos = new long[nCount]; lDpi1]2  
for(int i=0;i<nStartPos.length;i++) E=E<l?ob  
{ AM[:Og S  
nStartPos = input.readLong(); Ef!F;De)A  
nEndPos = input.readLong(); ]'G7(Y\)f  
} d !H)voX  
input.close(); :NLNxK  
} *O;N"jf  
catch(IOException e){e.printStackTrace ();} Nm~#$orI|  
catch(Exception e){e.printStackTrace ();} 9Dl \SF[  
} w&{J9'~  
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private void processErrorCode(int nErrorCode) q mB@kbt  
{ :wZZ 1qa  
System.err.println("Error Code : " + nErrorCode); .EcMn  
} |2# Ro*  
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mo  
//停止文件下载 J3]m*i5A  
public void siteStop() $enh45Wy  
{ ;w>B}v;RE  
bStop = true; <wC1+/]  
for(int i=0;i<nStartPos.length;i++) yiOF&  
fileSplitterFetch.splitterStop(); ^kq!/c3r  
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} (0+m&, z  
} iCS/~[  
//负责部分文件的抓取 !xI![N^  
**FileSplitterFetch.java =Vs<DO{|4q  
*/ H[r0jREK  
package NetFox; lg1D>=(mY  
f"Iyo:Wt  
2?j1~]DvZ  
import java.io.*; ,3j7Y5v  
import java.net.*; BP6Shc|C  
f/yK|[g~  
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public class FileSplitterFetch extends Thread { }#J}8.  
F'I6aE%  
K="+2]{I  
String sURL; //File URL NSq=_8  
long nStartPos; //File Snippet Start Position 5glGlD6R  
long nEndPos; //File Snippet End Position 0YL0Oa+7  
int nThreadID; //Thread's ID MF`'r#@:wa  
boolean bDownOver = false; //Downing is over yKJ^hv"#  
boolean bStop = false; //Stop identical YLGLr@:q  
FileAccessI fileAccessI = null; //File Access interface Q)>'fZ)  
EMG*8HRI>r  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException -
+>am?  
{ u
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this.sURL = sURL; jq)|Uq'6  
this.nStartPos = nStart; bed+Ur&  
this.nEndPos = nEnd; t3G'x1  
nThreadID = id; UZra'+Wb  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 $w\, ."y  
} V*}zwms6  
m##=iB|
;  
9:o3JGHSc  
public void run() AHGcWS\,X  
{ mQd?Tyvn  
while(nStartPos < nEndPos && !bStop) @ni~ij  
{ B5G$o{WM  
}^7V^W  
/3]|B%W9  
try{ 3)Y:c2  
URL url = new URL(sURL); 7krA+/Qr(  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); d}_c(  
httpConnection.setRequestProperty("User-Agent","NetFox"); 7w,FA  
String sProperty = "bytes="+nStartPos+"-"; =*jcO119L  
httpConnection.setRequestProperty("RANGE",sProperty); x3|'jmg  
Utility.log(sProperty); DlI5} Jh  
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}c%y0)fL
 
InputStream input = httpConnection.getInputStream(); ?C35   
//logResponseHead(httpConnection); ?M^t4nj  
"Ycd$`{Vgt  
3G^Ed)JvE  
byte[] b = new byte[1024]; *.g?y6d  
int nRead; EB<q.  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) mC`! \"w  
{ q;.]e#wvh  
nStartPos += fileAccessI.write(b,0,nRead); G>QTPXcD  
//if(nThreadID == 1) LnS>3$t*  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); MFuI&u!g:  
} +`-a*U94  
/MH@>C _  
i:ZA{hA`c  
Utility.log("Thread " + nThreadID + " is over!"); Ah{pidUx  
bDownOver = true; AW5g (  
//nPos = fileAccessI.write (b,0,nRead); QE2^.|d{  
} -QDgr`%5  
catch(Exception e){e.printStackTrace ();} 6/ipdi[ _  
} \DK*>
k  
} &,]+>  
D|9fHMg%  
vWs c{9  
//打印回应的头信息 (}1f]$V  
public void logResponseHead(HttpURLConnection con) 3:lp"C51  
{ nX%'o`f  
for(int i=1;;i++) EG4bFmcs  
{ 9'g{<(R]  
String header=con.getHeaderFieldKey(i); 2j1v.%  
if(header!=null) 3ohcHQ/a  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); (y*X8  
Utility.log(header+" : "+con.getHeaderField(header)); |wQZ~Ux:  
else ue<<Y"NR  
break; P1stL,  
} F t/ x5  
} s$x] fO  
}TJ|d=  
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public void splitterStop()  **w~  
{ % T\N@  
bStop = true; =@=R)C4f*  
} k=2l9C3Z  
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} ?3,tG z)  
OB^?cA>  
5dw@g4N %^  
/* oh0|2I
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**FileAccess.java D*'M^k|1  
*//文件访问(定位，写) A>%UYA  
package NetFox; h^kNM8  
import java.io.*; GY]6#
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}, &,Dt  
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public class FileAccessI implements Serializable{ %yM' Z[-  
N3p 7 0  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 {JCz^0DV  
RandomAccessFile oSavedFile; g*?+~0"`Y  
long nPos; =GKYroNM  
GtJ*&=(  
ANQa2swM  
public FileAccessI() throws IOException )-
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{ m_02"'  
this("",0); \}QuNwc  
}
2$zq (  
a& aPBv1  
>"g<-!p@  
public FileAccessI(String sName,long nPos) throws IOException 8~(+[[TQ@  
{ >ydb?
 
oSavedFile = new RandomAccessFile(sName,"rw"); [=ak>>8  
this.nPos = nPos; 'ag6B(0Z  
oSavedFile.seek(nPos); dIa(</ }  
} m4U+,|Fa  
s/vOxGc  
X#I`(iHY  
public synchronized int write(byte[] b,int nStart,int nLen) m2q;^o:J  
{ 'h6}cw+K  
int n = -1; fMEv85@JL  
try{ aU<D$I  
oSavedFile.write(b,nStart,nLen); *8X9lv.Z  
n = nLen; \.;ct  
} =>}.W:=  
catch(IOException e) dwbY"t[9  
{ *RbOQ86vP  
e.printStackTrace (); (&S[R{=^j  
} 4Re@QOZ  
n
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return n; G q:4rG|  
} T~~[a|bLa  
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} 2C33;?M  
M|5]
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^Ii \vk  
/* 5 (21gW9  
**SiteInfoBean.java 4 ^~zN"6]  
*/ r>:L$_]L  
package NetFox; *- IlF]  
RJ}yf|d-C  
JdUz!=I  
public class SiteInfoBean { RTgA[O4J  
Ns|V7|n]  
3pTS@  
private String sSiteURL; //Site's URL O`[iz/7m  
private String sFilePath; //Saved File's Path ;Ma/b=Y  
private String sFileName; //Saved File's Name 8LQ59K_WX  
private int nSplitter; //Count of Splited Downloading File ?F87C[o  
Y =g>r]2  
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public SiteInfoBean() =SK+\j$  
{//nSplitter的缺省值为5 w{e3U7;  
//default value of nSplitter is 5 jQxPOl$-  
this("","","",5); <qq'h  
} '6.>Wdd  
VU`z|nBW@  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) /,Dwu?Lcqp  
{ ]o[X+;Tj|  
sSiteURL= sURL; 3:~l2KIP4  
sFilePath = sPath; y@kcXlY  
sFileName = sName; 3$$5Mk(&  
this.nSplitter = nSpiltter; juYA`:qE&  
gN, k/U8  
I`"-$99|t1  
} ZO%fS'n  
Q@e*$<3  
4kaE}uKU  
public String getSSiteURL() 9QOr,~~s  
{ h8#5vO2  
return sSiteURL; dE5 5  
} ~~xyFT+{F  
4C,kA+P  
QxL@'n#5   
public void setSSiteURL(String value) zr3q>]oma  
{ <;z[+6T  
sSiteURL = value; $#G6m`V  
}
'Vm5Cs$  
z)&naw.  
4/HY[FT  
public String getSFilePath() ?z5ne??  
{ !c4)pMd  
return sFilePath; sP6 ):h  
} ZTh?^}/  
1Nl&4YLO  
Q/QQ:t<XUi  
public void setSFilePath(String value) qab) 1ft  
{ VBbUl|X\  
sFilePath = value; %="~\1y  
} 5Cc6, ]  
XN~#gm#  
g{A3W) [ b  
public String getSFileName() <ELziE~>V  
{ BcZEa^^~os  
return sFileName; 42Aje  
} TV1e bH7q  
6K4`;  
?jNF6z*M6  
public void setSFileName(String value) w69>tC  
{ wGOMUWAt  
sFileName = value; FG>;P]mvp  
}
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pAJ=f}",]E  
:u>W&D  
public int getNSplitter() 9E
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{ m\*&2Na  
return nSplitter; ~:/%/-^  
} ``(}4a  
[^?13xMb  
;f".'9 l^
 
public void setNSplitter(int nCount) }.fL$,7a  
{ E/wQ+rv  
nSplitter = nCount; ,_.@l+BM.  
} 6C:x6'5[  
} $kxu;I
 
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Yw~;g:
=  
/* 6?%]odI#  
**Utility.java ov\Ct%]  
*/ o5N]((9  
package NetFox; 0M#N=%31  
dr|| !{\  
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public class Utility { X+`ddX  
-@%t"8  
PU^[HC*K  
public Utility() W:VW_3  
{ *C4~}4WT\  

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} I$aXnd6)  
yD"]{  
//线程睡眠 s~'9Hv9  
public static void sleep(int nSecond) f*{M3"$E  
{ <)_:NRjBF&  
try{ X!U]`Qh  
Thread.sleep(nSecond); 6PiEa(  
} McT\ R{/  
catch(Exception e) ky'|Wk6   
{ a<f;\$h]  
e.printStackTrace (); zo_k\K`{@  
} ijvNmn1k  
} r@|R-Binz  
T1lXYhAWS  
//日志 IS
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public static void log(String sMsg) eZynF<i  
{ :6 Uk)  
System.err.println(sMsg);  AGh~8[  
} 536^PcJlN  
S8*^ss>?^R  
5+y@ ]5&g  
public static void log(int sMsg) *w=z~Jq^R"  
{ /t$rX3A  
System.err.println(sMsg); u
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} i%xI9BO9  
} OF-E6bc  
~@%(RMJm&  
'GrRuT<  
/* ?$<SCN=  
**TestMethod.java jVX._bEGX  
*/ s0gJ f[  
package NetFox; <Cu'!h_nL  
B:e.gtM5  
vAi"$e  
public class TestMethod { NV:>a  
Mx^y>\X)v  
kXigX
-  
public TestMethod() b+W)2rFO  
{ ///xx/weblogic60b2_win.exe ah 4kA LO  
try{ *]Fg
fttES  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 'n>K^rA  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); cL?\^K)  
SiteFileFetch fileFetch = new SiteFileFetch(bean); D._{E*vg  
fileFetch.start(); U%Dit  
} j -#E?&2  
catch(Exception e){e.printStackTrace ();} 0xN!DvCg>.  
(2: N;  
: @s8?eg  
} +:}kZDl@ X  
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ex.+'m<g  
public static void main(String[] args) &8Zeq3~  
{ T0g0jr{  
new TestMethod(); 1JIG+ZNmd  
} }|A
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} L?C\Q^0"`G  
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