http断点续传简单实现（java)

/* OADW;fj  
**SiteFileFetch.java {,u})U2  
*/ hw.>HT|.N  
package NetFox; bYoBJ #UX  
import java.io.*; s/B_  
import java.net.*; :dpwr9)  
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public class SiteFileFetch extends Thread { li,rPUCt  
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SiteInfoBean siteInfoBean = null; //文件信息Bean fs?H  
long[] nStartPos; //开始位置 ;6~5FTmV  
long[] nEndPos; //结束位置 Eh)V
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FileSplitterFetch[] fileSplitterFetch; //子线程对象 l4dG=x}M]  
long nFileLength; //文件长度 Oi zj|'  
boolean bFirst = true; //是否第一次取文件 z1]nC]2  
boolean bStop = false; //停止标志 :Nv7Wt!  
File tmpFile; //文件下载的临时信息 k'k}/Hxub  
DataOutputStream output; //输出到文件的输出流 Rj4C-X4=  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ([ -i5  
public SiteFileFetch(SiteInfoBean bean) throws IOException U1HG{u,"y  
{ ec`re+1r  
siteInfoBean = bean; +*Z'oCBJ,  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); h!v<J
  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ]Vmo>  
if(tmpFile.exists ()) gO)":!_n W  
{ zhm0J-g  
bFirst = false; CJER&"em7  
read_nPos(); a+cDH  
} lx=tOfj8  
else ]%y>l j?Y  
{ *c [^/  
nStartPos = new long[bean.getNSplitter()]; J8i,[,KcE  
nEndPos = new long[bean.getNSplitter()]; ~\8(+qIv%f  
} i/skU9  
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} 7F6B  
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public void run() s'
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{ [61*/=gWe  
//获得文件长度 K,
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//分割文件 k@un}}0r  
//实例FileSplitterFetch yi*EobP  
//启动FileSplitterFetch线程 A=5Ebu!z  
//等待子线程返回 KX]!yA  
try{ g&y^r/  
if(bFirst) %T\hL\L?  
{ $xbW*w  
nFileLength = getFileSize(); k}
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if(nFileLength == -1) I8j:{*h  
{ kaXq.  
System.err.println("File Length is not known!"); IhBc/.&RL  
} p7@R+F\.};  
else if(nFileLength == -2) ~!5=o{wy  
{ &e@)yVLL  
System.err.println("File is not access!"); 2jC`'8  
} :>2wVN&\c  
else !&>`  
{ (/N&_r4x  
for(int i=0;i<nStartPos.length;i++) q:TNf\/o  
{ pm,xGo2  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); "GQ Q8rQ  
} %^HE^
&  
for(int i=0;i<nEndPos.length-1;i++) fO&`A:JY  
{ y:}qoT_.  
nEndPos = nStartPos[i+1]; TKv!wKI  
} a!E22k?((z  
nEndPos[nEndPos.length-1] = nFileLength; N{S) b  
} |:&6eDlR  
} 8"9&x} tl-  
uT4|43< G  
nAEyL+6U  
//启动子线程 M@{#yEP  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; z__?kY  
for(int i=0;i<nStartPos.length;i++) |Z<\kx  
{ n)98NSVDbT  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ]5c(:T F  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), "mf$E|  
nStartPos,nEndPos,i); jt on\9  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ;//9,x9;t  
fileSplitterFetch.start(); U:C:ugm  
} *k}m?;esb  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ?nGiif  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); MCmb/.&wu  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", xdm\[s  
nEndPos = " + nFileLength); {]<c6*gQ  
// fileSplitterFetch[nPos.length-1].start(); gK`w|kh`  
,M;9|kE*  
Vv}R S@4U  
//等待子线程结束 ~qrSHn}+PU  
//int count = 0;  ]|.ked  
//是否结束while循环 ^0}ma*gi~  
boolean breakWhile = false; X!ruQem /  
jRg gj`o  
3WJk04r  
while(!bStop) #mw!_]  
{ @m9pb+=v  
write_nPos(); q\?s<l63  
Utility.sleep(500); {g<D:"Q  
breakWhile = true; $TXxhd 6  
ovTL'j!  
QMsq4yJ)%  
for(int i=0;i<nStartPos.length;i++) fUkqhqe  
{ 0X5cn 0L^  
if(!fileSplitterFetch.bDownOver) i
VI&  
{ {fzX2qMZ]  
breakWhile = false; bGH#s {'5  
break; j)mU`b_  
} A~bSB n: '  
} 5]N0p,f  
if(breakWhile) |(3y09  
break; #5@(^N5p`  
lx%c&~.DiB  
M\C9^DX{  
//count++; fd&Fn=!  
//if(count>4) q()o|V  
// siteStop(); T,pr&1]Lw  
} `Npa/Q  
xo_STLAw  
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System.err.println("文件下载结束！"); 'K?h6?#  
} S)WxTE9  
catch(Exception e){e.printStackTrace ();} RW. qw4  
} 2{rWAPHgz  
5-|!mSd  
DQQ]grU  
//获得文件长度 6DHK&<=D8  
public long getFileSize() +?{"Q#.>;  
{ z4:!*:.Asu  
int nFileLength = -1; )A7^LLzG  
try{ @(sz"  
URL url = new URL(siteInfoBean.getSSiteURL()); <eG|`  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 1_]X  
httpConnection.setRequestProperty("User-Agent","NetFox"); \%a0Lp{ I  
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|q*yuK/  
int responseCode=httpConnection.getResponseCode(); i-OD"5a`  
if(responseCode>=400) c,~uurVi  
{ !E 5FU *s  
processErrorCode(responseCode); 4^L;]v,|7  
return -2; //-2 represent access is error [Km{6L&  
} "/Qz?1>l+  
M%S7cIX ]F  
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String sHeader; :2?g_  
#KJ# 1  
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for(int i=1;;i++) 2?t@<M]  
{ ttsR`R1.k  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); lvke!~#  
//Utility.log(in.readLine()); q`c!!Lg  
sHeader=httpConnection.getHeaderFieldKey(i); 2LtDS?)@  
if(sHeader!=null) %} ``:  
{ yW|J`\`^T  
if(sHeader.equals("Content-Length")) ^5sA*%T4  
{ PXMd=,}  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); @
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break; HoGYgye=  
} MYS`@%ZV#k  
} F/s n"2  
else w \b+OW  
break; wXQxZuk[  
} JQ1MuE'  
} ]/=RABi  
catch(IOException e){e.printStackTrace ();} |U|>YA1[b  
catch(Exception e){e.printStackTrace ();} J\@6YU[A  
R.^]{5  
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Utility.log(nFileLength); i/9iM\2  
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return nFileLength; GTP'js  
} lmeTW0U@9(  
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n~I-mR)"  
//保存下载信息（文件指针位置） BDI|z/~&  
private void write_nPos() [H}> 2Q  
{ zZ=SAjT QP  
try{ :<J7g`f  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ^9
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output.writeInt(nStartPos.length); }4|EHhG  
for(int i=0;i<nStartPos.length;i++) ~Gu$EqQ  
{ Ek{QNlQ]4  
// output.writeLong(nPos); 6gV*G  
output.writeLong(fileSplitterFetch.nStartPos); #r'MfTr  
output.writeLong(fileSplitterFetch.nEndPos); &b} \).5E  
} <YaTr9%w  
output.close(); LiG$M{0  
} &i5@4,p y9  
catch(IOException e){e.printStackTrace ();} |.N[NY
  
catch(Exception e){e.printStackTrace ();} d_!Z /M,  
} 3`^@
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!Km[Qw k-  
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//读取保存的下载信息（文件指针位置） V]zc-gYI  
private void read_nPos() dCd~]CI  
{ <\&9Odqc  
try{ #Z%" ?RJ  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); hq=;ZI  
int nCount = input.readInt(); |7|S>h^  
nStartPos = new long[nCount]; 6'#5Dqw"r  
nEndPos = new long[nCount]; TjUwe@&Rw  
for(int i=0;i<nStartPos.length;i++) .?:*0
 
{ lFzVd N  
nStartPos = input.readLong(); =1IK"BA2?  
nEndPos = input.readLong(); }DhqzKl  
} ok:uTeJI  
input.close(); S1QMS  
} uM2@&)u  
catch(IOException e){e.printStackTrace ();} ot}erC2~  
catch(Exception e){e.printStackTrace ();} mku@n;Hl_  
} v;]rFc#Px[  
_?~%+Oz/  
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private void processErrorCode(int nErrorCode) f^F;`;z  
{ *Al@|5  
System.err.println("Error Code : " + nErrorCode); >d +
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} b$_81i  
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//停止文件下载 eAy,T<#  
public void siteStop() c{M ,K  
{ >#]A2,  
bStop = true; bU=Utniq  
for(int i=0;i<nStartPos.length;i++) gm9*z.S\'  
fileSplitterFetch.splitterStop(); 0kE[=#'.'  
i7Qb~RW  
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} .#( vx;  
} <*(Z}p  
//负责部分文件的抓取 Kip&YB%rk  
**FileSplitterFetch.java luoQ#1F?sl  
*/ MmT/J1zM  
package NetFox; I*u3
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bZ`v1d (r  
import java.io.*; K%z!#RyJ4  
import java.net.*; K\K& K~Z  
cN,*QN  
}3#\vn0gT
 
public class FileSplitterFetch extends Thread { 4XpWDfa.}  
xC`!uPk/pL  
,L<JG  
String sURL; //File URL ]+D@E2E
 
long nStartPos; //File Snippet Start Position rB[J*5v  
long nEndPos; //File Snippet End Position #mQ@4k9i  
int nThreadID; //Thread's ID 
$+4DpqJ  
boolean bDownOver = false; //Downing is over -UhpPw6  
boolean bStop = false; //Stop identical Btm,'kBG  
FileAccessI fileAccessI = null; //File Access interface 9j2t|D4uT  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException xw#CwMbbi  
{ 1:-'euA"  
this.sURL = sURL; yv,FzF}7  
this.nStartPos = nStart; 2zC4nF)>O  
this.nEndPos = nEnd; Ta?J;&<u]/  
nThreadID = id; (?4%Xtul1  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 m{q'RAw  
} (:l6R9'=  
82LE9<4A  
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public void run() eRMN=qP.q  
{ ^j}C]cq{Xg  
while(nStartPos < nEndPos && !bStop) a'VQegP(f\  
{ :kgh~mx5LF  
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try{ Df6
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URL url = new URL(sURL); #h;  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); k|;a"56F  
httpConnection.setRequestProperty("User-Agent","NetFox"); {)" 3  
String sProperty = "bytes="+nStartPos+"-"; (|QJ[@?q  
httpConnection.setRequestProperty("RANGE",sProperty); !Tnjha*  
Utility.log(sProperty); 0Ui.nz j  
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InputStream input = httpConnection.getInputStream(); 5 ^{~xOM5  
//logResponseHead(httpConnection); *Soi  
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byte[] b = new byte[1024]; B!RfPk1B<*  
int nRead; u zZ|0  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) U^PXpNQ'  
{ 3%POTAw%  
nStartPos += fileAccessI.write(b,0,nRead); <F9-$_m  
//if(nThreadID == 1) x{R440"  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); "| nXR8t.r  
} Wdd}y`lS  
 S!?T0c?>  
u({^8: AYu  
Utility.log("Thread " + nThreadID + " is over!"); .<m]j;|6  
bDownOver = true; Zl>SeTjB-  
//nPos = fileAccessI.write (b,0,nRead); ^6W}ZLp  
} k~[jk5te  
catch(Exception e){e.printStackTrace ();} LK'(OZ  
} H{}&|;0  
} E*'YxI  
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//打印回应的头信息 3fOOT7!FL  
public void logResponseHead(HttpURLConnection con) SdH=1zBc  
{ //@6w;P  
for(int i=1;;i++) 0+\725DJ  
{ gPMR,TU  
String header=con.getHeaderFieldKey(i); 88?bUA3]  
if(header!=null) Z`-$b~0  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ?1=.scmgDG  
Utility.log(header+" : "+con.getHeaderField(header)); k{vj,
#  
else PZ]tl  
break; S m(*<H  
} m H:Un{,  
} T!jh`;D+  
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public void splitterStop() {K|?i9K  
{
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bStop = true; 1H-Wk  
} hDXTC_^s  
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bm#5bhX\|  
} R}oN8
 
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(;fJXgj.  
/* Pe:)zt0  
**FileAccess.java dDS{XR  
*//文件访问(定位，写) Xqf\}p n  
package NetFox; ANm@$xO*  
import java.io.*; u|<?mA!  
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75\ZD-{T:  
public class FileAccessI implements Serializable{ j*3;G+  
S9dxrm?  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 rmg\Pa8W>  
RandomAccessFile oSavedFile; ,i_+Z |Ls  
long nPos; EZ!! V~  
=1[_#Moc6  
Zfs-M)  
public FileAccessI() throws IOException GgxPpS<ne  
{ Z=% j|xE_  
this("",0); `}Y)l:G*g  
} "dpjxH=xO  
A f`Kg-c_(  
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public FileAccessI(String sName,long nPos) throws IOException RLf-Rdx/  
{ nWK8.&{.  
oSavedFile = new RandomAccessFile(sName,"rw"); Y%i<~"k  
this.nPos = nPos; Mmz; uy_  
oSavedFile.seek(nPos); her>L3G-E  
} 3nA^s"#p  
#ed|0  
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public synchronized int write(byte[] b,int nStart,int nLen) jwwRejNV  
{ 8R)K$J$Hm  
int n = -1; DVd8Ix<  
try{ ";.j[p:gi  
oSavedFile.write(b,nStart,nLen); Hec8pL  
n = nLen; WSpF/Wwc  
} %Za}q]?  
catch(IOException e) IYn`&jS{  
{ )B]"""J  
e.printStackTrace (); wXQu%F3  
} ~2*LWH*@  
r (m3"Xu6O  
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return n; P 0\`4Cr!  
} 3nB
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z  
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} Nd(3q]{  
0^*,E/}P&  
;[o:VuTs  
/* K2*rqg  
**SiteInfoBean.java IWYQ67Yj   
*/ k*_Gg  
package NetFox; ]DnAW'm  
O#.YTTj  
=?|$}vDO[  
public class SiteInfoBean { pbKmFweq  
v,n 8$,  
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private String sSiteURL; //Site's URL Fepsa;\sU  
private String sFilePath; //Saved File's Path W9l](Ow  
private String sFileName; //Saved File's Name n\;;T1rM  
private int nSplitter; //Count of Splited Downloading File pYcs4f!?p  

#j7&2L  
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public SiteInfoBean() [%^0L~:  
{//nSplitter的缺省值为5 QE/kR!r  
//default value of nSplitter is 5 /- Gq`9Z  
this("","","",5); ]$#bNt/p  
} g]j&F65D  
~AWn 1vFc  
1Z0Qkd(  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) << =cZ.HP  
{ hXFT(J=  
sSiteURL= sURL; xjBY6Ylz  
sFilePath = sPath; KsGW@Ho:  
sFileName = sName; 9'(^Coq  
this.nSplitter = nSpiltter; j![1  
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wYe;xk`>  
} 'g<"@SS+  
<IIz-6*V  
}bihlyB&Q  
public String getSSiteURL() st??CX2  
{ n^1BtP0!  
return sSiteURL; q-CgXwU  
} }\m.~$|[  
Qu#[PDhb  
WS6Qp`c)e  
public void setSSiteURL(String value) PkFG0  
{ H3!9H  
sSiteURL = value; K91O$'J  
} Y*b$^C%2  
#[i3cn  
n
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public String getSFilePath() .
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{ ?6"U('y>n  
return sFilePath; R{[v#sF >#  
} "KF]s.  
!pj&h0CR  
BNk>D|D;  
public void setSFilePath(String value) S['rTuk  
{ !d 4DTo  
sFilePath = value; ^KD1dy3(  
} x [vbi  
n?c[ E+i;  
|L89yjhWBs  
public String getSFileName() pFs/ipZX^*  
{ ,2 xD>+=  
return sFileName; t"9r`0>  
} +9]t]Vrw  
s/t,6-~EH  
zk1]?  
public void setSFileName(String value) ZUj1vf6I  
{ \0Xq&CG=E  
sFileName = value; #'@@P6o5  
} 2f{p$YIt  
c0l?+:0M  
16N|  
public int getNSplitter() 7}NvO"u  
{ S@[NKY  
return nSplitter; 8B+C[Q:+'  
} uEh
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F<iV;+  
9s!R_R&W.  
public void setNSplitter(int nCount) ;dfIzi  
{ \PZ;y=]p}  
nSplitter = nCount; e34g=]"  
} K}N~KDW R|  
} d" 0&=/  
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Y_C6*T%  
/* ^N^s|c'  
**Utility.java OK-*TPrc  
*/ YHY*dk*|C  
package NetFox; yzl}!& E  
)b%zYD9p  
QxbG-B^)=  
public class Utility { PB*G#2W  
toU<InN  
EqBTN07dZS  
public Utility() YnU*MC}  
{ *T}c{/  
6)ysiAH?  
Jw;G_dQ[  
} eC<?g  
S&&QU#  
//线程睡眠 cb|hIn\>7  
public static void sleep(int nSecond) 1:yil9.\*  
{ #y"LFoJn  
try{ UCj<FN `  
Thread.sleep(nSecond); YuHXm3[  
} :}q)]W  
catch(Exception e) @o1#J`rv  
{ z[vu-f9  
e.printStackTrace (); *Jt+-ZM  
} LEN=pqGJ.  
} 3me&isKL  
6~>h;wC  
//日志 o*E32#l  
public static void log(String sMsg) > Xij+tt{  
{ Hj1?c,mo4  
System.err.println(sMsg); A|4 3W=  
} aMT=pGU  
C]3:&dx9  
Y~*aA&D  
public static void log(int sMsg) x&JD~,Y  
{ ~PAI0+*"q  
System.err.println(sMsg); a-nn[j  
} Gf
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} 9GT}_ ^fb  
Gr}NgyT<!D  
B+jh|@-  
/* PQ;9iv  
**TestMethod.java B>I:KGkV  
*/ _d^d1Q}V  
package NetFox; +BhJske  
S{)K_x  
|#BN!kc  
public class TestMethod { ^xScVOdP  
L&=r-\.ev  
u(hJyo}  
public TestMethod() 1`s^r+11:  
{ ///xx/weblogic60b2_win.exe 6Z=Qs=q  
try{ 92C; a5s  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); (!efaj  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); TI2K_'  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 2qVoe}F  
fileFetch.start(); 0DnOO0Nc  
} f<oU"WM  
catch(Exception e){e.printStackTrace ();} O0_RW`69  
rR/{Yx4  
'-XO;{,-R  
} C CLc,r>)  
UUvCi+W  
?'H+u[1.  
public static void main(String[] args) =\MAz[IDj  
{ mQSn*;9\T3  
new TestMethod(); )%kiM<})  
} d0Ubt  
} M} ri>o  
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