http断点续传简单实现（java)

/* @CaD8%j{  
**SiteFileFetch.java ]EM)_:tRf  
*/ +:"6`um|  
package NetFox; L.0} UXd  
import java.io.*; :Q r7:$S^  
import java.net.*; P"=UI$HN  
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public class SiteFileFetch extends Thread { Wt+y-ES  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 1&% d  
long[] nStartPos; //开始位置 Y!
a+#N!  
long[] nEndPos; //结束位置 a0?iR5\  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 t$y&=v  
long nFileLength; //文件长度 q3x;_y^  
boolean bFirst = true; //是否第一次取文件 lNaez3  
boolean bStop = false; //停止标志 Ie2w0Cs28  
File tmpFile; //文件下载的临时信息 .hQ3A"  
DataOutputStream output; //输出到文件的输出流 CFBUQMl>  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 2-6.r_  
public SiteFileFetch(SiteInfoBean bean) throws IOException /G)KkB
C  
{ 7/&C;"  
siteInfoBean = bean; -[f"r`  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); sw$R2K{y  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); !k:zLjtp  
if(tmpFile.exists ()) @vdc)vN[/  
{  UL)"  
bFirst = false; 8)W?la8'p  
read_nPos(); ^/%o%J&Hz  
} 17i<4f#  
else z<oE!1St  
{ TRk ?8  
nStartPos = new long[bean.getNSplitter()]; co<2e#p;  
nEndPos = new long[bean.getNSplitter()]; 4aalhy<j  
} 1=/doo{^  
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} =M1a0i|d  
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public void run() q'%[[<  
{ .Yu<%  
//获得文件长度 3^02fy  
//分割文件 >}<29Ii  
//实例FileSplitterFetch |t&G&)~:  
//启动FileSplitterFetch线程 0NCOz(L/  
//等待子线程返回 bl" (<TM  
try{ 3@PUg(M  
if(bFirst) +p9LE4g7Q  
{ U^[cYT
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nFileLength = getFileSize(); lruF96C/Y  
if(nFileLength == -1) VQy9Y  
{ M.xhVgFf)  
System.err.println("File Length is not known!"); Hi; K"H]x1  
} ]k'#g Z$  
else if(nFileLength == -2) #MhNdH#  
{ < v|%K.yd  
System.err.println("File is not access!"); u8-a-k5<  
} MtpU~c  
else MiSja#"+A  
{ ]5} -y3  
for(int i=0;i<nStartPos.length;i++) lL:KaQ0E  
{ A~6%,q@^jh  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Qb!!J4|!  
} z'?7]C2b  
for(int i=0;i<nEndPos.length-1;i++) 5T$
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{ saGRP}7?  
nEndPos = nStartPos[i+1]; -T
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} hsTFAfa'  
nEndPos[nEndPos.length-1] = nFileLength; }mKGuCoH>  
} hFsA_x+L;  
} jzl?e[qPA  
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//启动子线程 :`+|'*b(A  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; S
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for(int i=0;i<nStartPos.length;i++) IvEMg2f}  
{ 2YL`3cgfb  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Q3'fz 9v  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 0hrCG3k.91  
nStartPos,nEndPos,i); 0V<Aub[${  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); x r-;,W  
fileSplitterFetch.start(); _7Xd|\Zc  
} ZB~l2  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), rnnX|}J  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); "%{,T  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Tg"'pO  
nEndPos = " + nFileLength); ]LEoOdDN"C  
// fileSplitterFetch[nPos.length-1].start(); 6uu^A9x  
7))y}N:p
 
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//等待子线程结束 FX%t  
//int count = 0; ^~ Ekg:`  
//是否结束while循环 N@k3$+ls  
boolean breakWhile = false; d>lt  
+<S9E'gT3V  
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while(!bStop) &?SX4c~?u  
{ W3D
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write_nPos(); C:]/8l  
Utility.sleep(500); M:R8<.{  
breakWhile = true; P7's8K
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for(int i=0;i<nStartPos.length;i++) dv"as4~%  
{ f'1(y\_fb  
if(!fileSplitterFetch.bDownOver) c*N50%=4  
{ Iq)(UfaSve  
breakWhile = false; ctp?y  
break; rpUy$qrRc  
} mbF(tSy  
} rei 8LW  
if(breakWhile) dX_!0E[c  
break; L<bYRGz  
J"diFz+20  
fx<FIj7  
//count++; sB?2*S"X)<  
//if(count>4) 8$\Za,)g  
// siteStop(); 6tOCZ'f  
} ?Fce!J  
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System.err.println("文件下载结束！"); i][f#e4  
} F4GP7]  
catch(Exception e){e.printStackTrace ();} gh TcB  
} 8jRs=I  
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//获得文件长度 wAw42{M  
public long getFileSize() 8h@q
 
{ },ra
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int nFileLength = -1; e,EK,,iY5  
try{ |)9thIQF  
URL url = new URL(siteInfoBean.getSSiteURL()); 1hR (N  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); -^yXLa;D  
httpConnection.setRequestProperty("User-Agent","NetFox"); QS^~77q  
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int responseCode=httpConnection.getResponseCode(); xZX`%f-  
if(responseCode>=400) s8^~NX(xdy  
{ 88 {1mA,v  
processErrorCode(responseCode); fO6[!M(  
return -2; //-2 represent access is error xPt*CB  
} 7skljw(  
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String sHeader; 7!pLK&_  
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for(int i=1;;i++) }g>kpa0c  
{ Y=E9zUF  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Rv,82iEKs  
//Utility.log(in.readLine()); qYK4)JP  
sHeader=httpConnection.getHeaderFieldKey(i); @M=$qO_$9  
if(sHeader!=null) IhE9snJ[  
{ (VyA6a8  
if(sHeader.equals("Content-Length")) T'.[F  
{ rIVvO  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); JT04vm4  
break; 3E,DipHg  
} FqwIJ|ct  
} \ZMP_UU(  
else Z ] 
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break; r?pZ72q  
} s O=4IBE  
} HMV)U
{  
catch(IOException e){e.printStackTrace ();} :N2E}hx
k  
catch(Exception e){e.printStackTrace ();} P[FV2R~  
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Utility.log(nFileLength); Q/py qe G  
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return nFileLength; }~F~hf>s  
} ^LVk5l)\>g  
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]boE{R!I  
//保存下载信息（文件指针位置） L6+C]t}>6  
private void write_nPos() 9/@ &*  
{ paWxanSt  
try{ TGf;_)El  
output = new DataOutputStream(new FileOutputStream(tmpFile)); XFQNr`  
output.writeInt(nStartPos.length); +Rqbf  
for(int i=0;i<nStartPos.length;i++) |c0,  
{ 4z_n4=  
// output.writeLong(nPos); @r<b:?u  
output.writeLong(fileSplitterFetch.nStartPos); =WK04\H  
output.writeLong(fileSplitterFetch.nEndPos); e[{mVhg4E  
} 89Z#|#uM5  
output.close(); d;=u  
} !^iwQ55e2A  
catch(IOException e){e.printStackTrace ();} _{$fA6C  
catch(Exception e){e.printStackTrace ();} qfYG.~`5  
} w{`Acu  
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//读取保存的下载信息（文件指针位置） 59<hV?  
private void read_nPos() zsVcXBz  
{ =((yWn+t  
try{ OPuj|%Wgw  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); OxQYNi2  
int nCount = input.readInt(); 6\n?48x}  
nStartPos = new long[nCount]; zTY;8r+  
nEndPos = new long[nCount];
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for(int i=0;i<nStartPos.length;i++) jO8X:j09A  
{ 8KMvAc  
nStartPos = input.readLong(); ETfF5i}  
nEndPos = input.readLong(); ? %(spV  
} }G'XkoI&  
input.close(); k!3 cq)  
} GoIQ>n
 
catch(IOException e){e.printStackTrace ();} O~PChUU*Y  
catch(Exception e){e.printStackTrace ();} 0Z HDBh  
} &94W-zh  
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private void processErrorCode(int nErrorCode) aQUGNa0+d  
{ pOA!#Aj)  
System.err.println("Error Code : " + nErrorCode); BpH%STEN  
} VEs5;]#<2D  
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//停止文件下载 g^l RG3a  
public void siteStop() Ur!~<4GO  
{ d1]i,C~Y  
bStop = true; YQd:M%$  
for(int i=0;i<nStartPos.length;i++) wL3,g2-L  
fileSplitterFetch.splitterStop(); $a(`ve|  
1~\M!SQ)  
|m;L?)
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} m`}{V5;  
} xu\eXx6H  
//负责部分文件的抓取 n]yEdL/1  
**FileSplitterFetch.java ashar&'  
*/ x[i`S8D  
package NetFox; PeTA$Yl  
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import java.io.*; |V|+lx'sc  
import java.net.*; %3o`j<  
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public class FileSplitterFetch extends Thread { 3t"4TjAy  
6BAW  
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String sURL; //File URL ;ME)Og  
long nStartPos; //File Snippet Start Position gzdG6"  
long nEndPos; //File Snippet End Position ;Vu5p#,O<M  
int nThreadID; //Thread's ID u0 y 1  
boolean bDownOver = false; //Downing is over 2@khSWV  
boolean bStop = false; //Stop identical 4kl Ao$  
FileAccessI fileAccessI = null; //File Access interface X`JVR"=4  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException gl7|H&&xV  
{ }]6f+  
this.sURL = sURL; f p[,C1U  
this.nStartPos = nStart; qCPmbg  
this.nEndPos = nEnd; %d;ezY'2  
nThreadID = id; (sTuG}  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 t ls60h  
} 1m@^E:w  
{whvTN1#dh  
,}SCa'PB  
public void run() eQDX:b
 
{ 3EK9,:<Cf  
while(nStartPos < nEndPos && !bStop) u2iXJmM*  
{ s'\$t  
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try{ RU#F8
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URL url = new URL(sURL); 1/Zh^foG  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); se9>.}zZN  
httpConnection.setRequestProperty("User-Agent","NetFox"); j !H^-d}q  
String sProperty = "bytes="+nStartPos+"-"; sa&) #Z:  
httpConnection.setRequestProperty("RANGE",sProperty); 3tAU?sV!  
Utility.log(sProperty); SA"8!soY3  
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hdma=KqZ(  
InputStream input = httpConnection.getInputStream(); <q2?S  
//logResponseHead(httpConnection); *rh,"Zo  
s:>\/[*>0c  
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byte[] b = new byte[1024]; Jkt4@h2Q}  
int nRead; 6iA( o*'Yn  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) =O$M_1lp  
{ kG0Yh2;#  
nStartPos += fileAccessI.write(b,0,nRead); c&nh>oN  
//if(nThreadID == 1) p&b5% 4P  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); PnYBy| yl  
} </`yd2>
 
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Utility.log("Thread " + nThreadID + " is over!"); gm"#:< )  
bDownOver = true; b #fTAC;<  
//nPos = fileAccessI.write (b,0,nRead); Ea $aUORm  
} (eWPis[  
catch(Exception e){e.printStackTrace ();} YN/}9.  
} [g|Y7.j8  
} Rl~T$ Ey  
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//打印回应的头信息 EcL-V>U#M  
public void logResponseHead(HttpURLConnection con) ]d}0l6  
{ 3G}AH E4  
for(int i=1;;i++) 5Wx~ZQZ  
{ aHzHvl  
String header=con.getHeaderFieldKey(i); b;cMl'  
if(header!=null) E%N2k|%8d_  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); <%?#AVU[  
Utility.log(header+" : "+con.getHeaderField(header)); o4y']JSN  
else ~FU@wV^  
break; d^E [|w;  
} /0MDISQy9  
} ?Bi*1V<R  
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public void splitterStop() $A_]:qI2  
{ <If35Z)~  
bStop = true; Q>< 0[EPj3  
} <.K4JlbT  
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} -V.d?A4"  
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/* +j14Q$  
**FileAccess.java l! bv^  
*//文件访问(定位，写) i]{1^pKq  
package NetFox; 3>M&D20Z  
import java.io.*; !U%T&?E l  
>/$Fh:R-  
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public class FileAccessI implements Serializable{ -e GL)M  
W!Gdf^Yy<  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 (.Y/  
RandomAccessFile oSavedFile; rh*sbZ68>E  
long nPos; 1Tp/MV/>  
$g9**b@  
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public FileAccessI() throws IOException OHrY(I6  
{ ZD/jX_!t  
this("",0); +0wT!DZW\=  
} 9p* gU[  
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public FileAccessI(String sName,long nPos) throws IOException /UcV  
{ uP $Cj  
oSavedFile = new RandomAccessFile(sName,"rw"); zw<p74DH  
this.nPos = nPos; . 5y"38e  
oSavedFile.seek(nPos); ZzGahtx)Y  
} w8Q<r.  
)::>q5c  
9# 4Y1LS)  
public synchronized int write(byte[] b,int nStart,int nLen) #FOqP!p.E  
{ BimjQ;jtI  
int n = -1; a3SlxsWW  
try{ F'}'(t+oAm  
oSavedFile.write(b,nStart,nLen); e!-,PU9+  
n = nLen; .R*!aK  
} "^j>tii  
catch(IOException e) O)|P,?  
{ Xr63?N  
e.printStackTrace (); BAj-akc f  
} #hfuH=&oh  
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return n; %q;jVj[  
} g:l.MJT  
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} BaF!O5M  
620%Z*   
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/* &GTI  
**SiteInfoBean.java 3f Xv4R;!:  
*/ \`V$ 'B{.  
package NetFox; Qhi '')Q  
Y/<lWbj*A  
'+>fFM,*B  
public class SiteInfoBean { / O/`<  
7M_U2cd|TD  
gbeghLP[?  
private String sSiteURL; //Site's URL YpAg  
private String sFilePath; //Saved File's Path |'ln?D:&  
private String sFileName; //Saved File's Name n6d9\  
private int nSplitter; //Count of Splited Downloading File V"o7jsFH6n  
Jf)bHjC_V  
u=F+(NE"  
public SiteInfoBean() \6?A!w~6  
{//nSplitter的缺省值为5 #o/H~Iv  
//default value of nSplitter is 5 `O?TUQGR  
this("","","",5); /M~!sPW&?  
} cq&*.  
'TC/vnM  
<:/&&@2  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) XIo55*  
{ enNiI$H]`_  
sSiteURL= sURL; `(+o=HsD  
sFilePath = sPath; iB0WEj[?  
sFileName = sName; ,r^M?>  
this.nSplitter = nSpiltter; u?Tpi[ #  
5AS[\CB4  
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}
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UtB6V)YI  
public String getSSiteURL() =
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{ aV o;~h~  
return sSiteURL; _I`,Br:N  
} heaRX4  
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public void setSSiteURL(String value) ,:fl?x.X  
{ $&s=68  
sSiteURL = value; Om'+]BBN  
} 93+"D`  
g*)K/Z0pJ$  
u~ ~R9.
 
public String getSFilePath() M/?KV9Xk2  
{ 9odJr]  
return sFilePath; {8,<ZZ_  
} 5(W"-A}  
YCe7<3>J4  
TSAU?r\P  
public void setSFilePath(String value) & gJV{V5Ay  
{ ""Zp:8o  
sFilePath = value; ^JZ^>E~  
} \\BCcr\l  
~U(,TjJb  
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public String getSFileName()  nVu&/  
{ o-xDh7v  
return sFileName; di)*-+  
} 9!9Z~/*m  
W3vi@kb]  
j*
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public void setSFileName(String value) mNf8kwr  
{ pME{jD  
sFileName = value; {mWui9 %M  
} }>^Q'BW;65  
*19ax&|*S  
< v]3g  
public int getNSplitter() <R%;~){  
{ 6Ao%>;e*  
return nSplitter; LA_3=@2.H  
} JGC=(;  
*`j-i  
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public void setNSplitter(int nCount) I$Qs;- (  
{ 5qg2Zc~  
nSplitter = nCount; +jg9$e"  
} ;fw1
 
} ky 8ep  
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/* "fg](Cp[z  
**Utility.java
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*/ <APB11  
package NetFox; mrm^e9*Z  
=X?\MVWB  
) \Y7&  
public class Utility { i>EgG5iJ  
7NC=*A~  
1h*)@  
public Utility() 9ukg}_Hx  
{ D+~_TA  

1)}=bhT  
^8 ' sib  
} J--m[X  
Ggh.dZI4  
//线程睡眠 MYBx&]!\  
public static void sleep(int nSecond) yCJFo  
{ st"{M\.p  
try{ Oz|K8p  
Thread.sleep(nSecond); 79\JxiSB  
} >0{S  
catch(Exception e) |IunpZV  
{ Ngb(F84H?  
e.printStackTrace (); v+jsC`m  
} h25G/`  
} IHgeQ F ~  
*lef=:&,,  
//日志 ,uzN4_7u  
public static void log(String sMsg) *. 3N=EO  
{ fzjU<?}  
System.err.println(sMsg);
| ohL]7b<  
} T&86A\D\z  
%/>xO3"T  
X2tk[Kr  
public static void log(int sMsg) |uW:r17  
{ 9]t[J_YM  
System.err.println(sMsg); BmHwu{n'  
} tO_H!kP  
}  )1g"?]  
fN"(mW>!  
tBTTCwNT%  
/* 2_Wg!bq  
**TestMethod.java 64-#}3zL  
*/ xEuN   
package NetFox; _"4xKh)  
GE>[*zN  
9Pw0m=4  
public class TestMethod { 1 T130L  
0Z|FZGRP  
%{6LUn  
public TestMethod() OMwsbp&  
{ ///xx/weblogic60b2_win.exe A:<;M@q!  
try{ X=8Y&#%  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); [m+iQVk'  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); @aQ1khEd  
SiteFileFetch fileFetch = new SiteFileFetch(bean); y~IuPc  
fileFetch.start(); yL
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} n.hv!W0  
catch(Exception e){e.printStackTrace ();} M MzGd:0b  
w&4~Q
4  
y7KzW*>g:  
} ]|_\x
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public static void main(String[] args) X7L8h'(@  
{ OT^%3:
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new TestMethod(); B3Jgd,[  
} 9dMrgz&'  
} :';L/x>  
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