http断点续传简单实现（java)

/* -n:2US<  
**SiteFileFetch.java ( %sfwv  
*/ +aL6$  
package NetFox; ^aaj=p:cV  
import java.io.*; oX6Cd:c-  
import java.net.*; yc0

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public class SiteFileFetch extends Thread { iu{y.}?  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 2-S}#S}2C  
long[] nStartPos; //开始位置 1drg5  
long[] nEndPos; //结束位置 k1[`2k:Hk  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 "4XjABJ4'  
long nFileLength; //文件长度 NiG&Lw*8  
boolean bFirst = true; //是否第一次取文件 41R~.?  
boolean bStop = false; //停止标志 Vb 36R_u  
File tmpFile; //文件下载的临时信息 (ht"wY#T<(  
DataOutputStream output; //输出到文件的输出流 w[2E:Nj  
P'$2%P$8:~  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） $zz4A~   
public SiteFileFetch(SiteInfoBean bean) throws IOException |QrVGm@2  
{ QP%AJ[3ea%  
siteInfoBean = bean; )~)T[S  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); OfLj 4H6Q  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); =>*}qen  
if(tmpFile.exists ()) )m-(-I  
{ 7\dt<VV  
bFirst = false; x+sSmW  
read_nPos(); }T%E;m-  
} ^g'uR@uU  
else EhW
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{ :hHKm|1FE  
nStartPos = new long[bean.getNSplitter()]; V\Lh(zPt  
nEndPos = new long[bean.getNSplitter()]; |}l/6WHB  
} y]Q/(O  
}m!T~XR</  
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} p3%cb?G%w  
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public void run() zPvTRW~H\  
{ NR^Z#BU  
//获得文件长度 gYL#} )g  
//分割文件 787i4h:71  
//实例FileSplitterFetch y_IF{%i  
//启动FileSplitterFetch线程 * se),CP!s  
//等待子线程返回 @M*5q# s  
try{ <SRSJJR|(  
if(bFirst) [c>YKN2qa  
{ kDKfJp&a  
nFileLength = getFileSize(); -z/>W+k  
if(nFileLength == -1) o>M&C X+j$  
{ ?f6Fj  
System.err.println("File Length is not known!"); mqQ//$Y   
} B3u:D"
t  
else if(nFileLength == -2) BBoVn^Z*R  
{ Mc|UD*Z  
System.err.println("File is not access!"); E-rGOm" m  
} c"'JMq  
else ;>p{|^X0D  
{ %Y].i/".;P  
for(int i=0;i<nStartPos.length;i++) Yv;iduc('  
{ #w[Ie+  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); !"^//2N+,  
} m!<uY?,hf  
for(int i=0;i<nEndPos.length-1;i++) y#{> tC  
{ d_Y7/_i  
nEndPos = nStartPos[i+1]; k8sjW!2  
} 5,V3_p:)VI  
nEndPos[nEndPos.length-1] = nFileLength; K30{Fcb< h  
} 1`&"U[{  
} tw]Q5:6  
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//启动子线程 9
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; SnW>`  
for(int i=0;i<nStartPos.length;i++) [)p>pA2GZj  
{ ?F%,d{^  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ON3~!Q)  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 3hzKd_  
nStartPos,nEndPos,i); bu r0?q
  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Oc?]L&ap  
fileSplitterFetch.start(); czp}-{4X  
} m:{IVvN
_  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), [[0u|`T/  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); g)~"-uQQ  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ^b`aO$  
nEndPos = " + nFileLength); 1lQO`CmR6M  
// fileSplitterFetch[nPos.length-1].start(); Ut^ {4_EC  
vqJjAls  
0=KyupwXC  
//等待子线程结束 8d"Ff  
//int count = 0; <@2g.+9  
//是否结束while循环 %FO#j6  
boolean breakWhile = false; >FM2T<.;  
aRF}FE,u  
V17SJSC-  
while(!bStop) dJD8c2G  
{ J9*$@&@S  
write_nPos(); BO)Q$*G~JD  
Utility.sleep(500); =6:>C9  
breakWhile = true; EG[Rda  
5ki<1{aVtZ  
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for(int i=0;i<nStartPos.length;i++) u'+;/8  
{ #Z]l4d3{T  
if(!fileSplitterFetch.bDownOver) FpM0%   
{ z<9wh2*M  
breakWhile = false; \bPSy0  
break;
[GqQ6\  
} NvqIYW  
} Pwg?a  
if(breakWhile) Ryrvu1 k  
break; B)}.
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//count++; Tweku}D7  
//if(count>4) nL@(|nJ[  
// siteStop(); ,4tuWO)"  
}
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System.err.println("文件下载结束！"); yz7X7mAo  
} tlJ@@v&=  
catch(Exception e){e.printStackTrace ();} >q7/zl  
} 5.3=2/  
U+FI^Xrt#  
EAPjQA-B?  
//获得文件长度 +#V.6i  
public long getFileSize() >`(]&o6<$  
{ 1rLK1X  
int nFileLength = -1; oDBv5  
try{ zIT)Hs5  
URL url = new URL(siteInfoBean.getSSiteURL()); 7`_`V&3s  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 82*nC!P3E  
httpConnection.setRequestProperty("User-Agent","NetFox"); bs9X4n5  
ZtLZW/`  
}s++^uX6  
int responseCode=httpConnection.getResponseCode(); #Li6RSeW  
if(responseCode>=400) p]E\!/  
{ n/Fx2QC{  
processErrorCode(responseCode); 2Mo oqJp  
return -2; //-2 represent access is error ]u<8jr  
} wXKg^%t\  
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String sHeader; _ ,~D]JYE  
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O ! iN  
for(int i=1;;i++) A$o7<Hx  
{ +ko-oZ7V  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); KqhE=2,  
//Utility.log(in.readLine()); UrJrvx  
sHeader=httpConnection.getHeaderFieldKey(i); &~{0@/
 
if(sHeader!=null) * ,#SwZ  
{ _k O<|ev  
if(sHeader.equals("Content-Length")) ~lH_d[  
{ @h)Z8so  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); $WICyI{$  
break; :F`-<x/  
} _A]=45cn~  
} P?/Mrz   
else l:- <CbG  
break; GX0S9s  
}  Xn=  
} i!u:]14>  
catch(IOException e){e.printStackTrace ();} 7+;CA+;  
catch(Exception e){e.printStackTrace ();} h6~H5X  
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Utility.log(nFileLength); Bm4fdf#A]  
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return nFileLength; Z%$tV3a?  
} :[d*  
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//保存下载信息（文件指针位置） !Y^3%B%  
private void write_nPos() aaRc?b'/  
{ A3eus
 
try{  4"~F  
output = new DataOutputStream(new FileOutputStream(tmpFile)); }!*CyO*  
output.writeInt(nStartPos.length); *iiyU}x  
for(int i=0;i<nStartPos.length;i++) %Fp1c K  
{ vugGMP;D(  
// output.writeLong(nPos); f=paa/k0  
output.writeLong(fileSplitterFetch.nStartPos); 0'zX6%  
output.writeLong(fileSplitterFetch.nEndPos); uq\[^  
} OKV/=]GS  
output.close(); ~ya@ YP]';  
} Bv{DZ?{s  
catch(IOException e){e.printStackTrace ();} 'y%*W:O  
catch(Exception e){e.printStackTrace ();} 6Ij'z9nJw  
} Zonr/sA~  
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//读取保存的下载信息（文件指针位置） p-f"4vH  
private void read_nPos() HApjXv!U[  
{ BFvRU5&Sz  
try{ ,t@B]ll  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); |3P dlIbO  
int nCount = input.readInt(); QE4TvnhK  
nStartPos = new long[nCount]; ^,{ r[}  
nEndPos = new long[nCount]; RN"Ur'+  
for(int i=0;i<nStartPos.length;i++) O#n=mJ  
{ ycj\5+g  
nStartPos = input.readLong(); &F~97F)A)  
nEndPos = input.readLong(); cI (}  
} s_ %LU:WC  
input.close(); bx:j`5Uj`  
} 'cPE7uNT  
catch(IOException e){e.printStackTrace ();} N7UGgn=  
catch(Exception e){e.printStackTrace ();} ]/[$3rPwZ  
} w`
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private void processErrorCode(int nErrorCode) :0'vzM  
{ (w1$m8`=  
System.err.println("Error Code : " + nErrorCode); B\\M%!a>  
} @n^2UJ  
X86r`}  
a[ yyEgm2  
//停止文件下载 Mz: "p.  
public void siteStop() /3j3'~0  
{ UO4
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bStop = true; eOZ"kw"uHu  
for(int i=0;i<nStartPos.length;i++) Ma^}7D /  
fileSplitterFetch.splitterStop(); ,m[#<}xXA  
`]4tJJy$  
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} wxE'h~+  
} #L+ZH
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//负责部分文件的抓取 A7R
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**FileSplitterFetch.java P~h0Ul  
*/ l,ic-Y1  
package NetFox; .TO#\!KBv  
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import java.io.*; C&f{Lp
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import java.net.*; uJU;C.LX  
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public class FileSplitterFetch extends Thread { thSXri?kl  
7_`_iymR  
#B5-3CwB  
String sURL; //File URL ;^ff35EE8  
long nStartPos; //File Snippet Start Position (l}nwyh5  
long nEndPos; //File Snippet End Position iQvqifDmh  
int nThreadID; //Thread's ID WO=P~F<  
boolean bDownOver = false; //Downing is over +pxt
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boolean bStop = false; //Stop identical T/P   
FileAccessI fileAccessI = null; //File Access interface [<.dOe7|  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ?i$MinK  
{ H](TSt<Q"  
this.sURL = sURL; +r$VrNVs  
this.nStartPos = nStart; &IP`j~b  
this.nEndPos = nEnd; rTzXRMv@o  
nThreadID = id; $fwj8S7$  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 B~`:?f9ny5  
} :.crES7<[X  
.NMZHK?%  
+kx#"L:  
public void run() uo3o[H&#  
{ qv8B$}FU  
while(nStartPos < nEndPos && !bStop) r TK)jxklX  
{ Vo9FlYj  
/gP"X1.  
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try{ p{;FO?  
URL url = new URL(sURL); B:fulgh2ni  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); LT:8/&\  
httpConnection.setRequestProperty("User-Agent","NetFox"); E+P-)bRa  
String sProperty = "bytes="+nStartPos+"-"; &G_XgQsg{  
httpConnection.setRequestProperty("RANGE",sProperty); %D>cY!  
Utility.log(sProperty); M<xF4L3]  
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InputStream input = httpConnection.getInputStream(); vq1u!SY  
//logResponseHead(httpConnection); }T"&4Rvs2R  
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byte[] b = new byte[1024]; CPJ%<+4%b  
int nRead; \1oN't.  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) u(g9-O  
{ s$xm  
nStartPos += fileAccessI.write(b,0,nRead); U?j[ 8z  
//if(nThreadID == 1) 1(qL),F;  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); *_eY +\j  
} JxQGL{) >  
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Utility.log("Thread " + nThreadID + " is over!"); ?;DzWCL~9  
bDownOver = true; BCt>P?,UO  
//nPos = fileAccessI.write (b,0,nRead); B1 xlWdm  
} !gj_9"<  
catch(Exception e){e.printStackTrace ();} yAu.=Eo7  
} +[Q`I*C  
} 34t[]v|LD  
b\C1qM4  
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//打印回应的头信息 @O HsM?nW  
public void logResponseHead(HttpURLConnection con) [ip}f4K  
{ W@61rT}c  
for(int i=1;;i++) J+YoAf`hi  
{ A3Y}|7QA  
String header=con.getHeaderFieldKey(i); -!X\xA/KN  
if(header!=null) =]P|!$!}0  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); **F-#",  
Utility.log(header+" : "+con.getHeaderField(header)); ,m;G:3}48  
else +{cCKR
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break; /}=cv>S5V  
} G9h Bp  
} jNW/Biy4u  
zI'c'X1,  
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public void splitterStop() :YNXS;>)!  
{ J pKCux  
bStop = true; z}2  
} [#/@v/`  
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} >C/O >g  
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VevDW }4q*  
/* c)zwyBz  
**FileAccess.java y@\J7 h:  
*//文件访问(定位，写) `,)%<}  
package NetFox; @!%HEs!# #  
import java.io.*; yGlOs]>n  
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public class FileAccessI implements Serializable{ D*!9K8<o  
"K#zY~>L  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 w'<"5F`  
RandomAccessFile oSavedFile; iTJE:[W"y  
long nPos; I|)U>bV  
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public FileAccessI() throws IOException M[?0 ^ FBx  
{ myDcr|j-a  
this("",0); ^(1S`z$  
} io*iA<@Gx  
aaFt=7(K  
n!%'%%o2v  
public FileAccessI(String sName,long nPos) throws IOException QP!0I01  
{ qp2&Z8S\D  
oSavedFile = new RandomAccessFile(sName,"rw"); "i;"  
this.nPos = nPos; w>6cc#>q  
oSavedFile.seek(nPos); ^-26K|{3  
} KNqs=:i  
Wh1'?#  
EGK7)O'W  
public synchronized int write(byte[] b,int nStart,int nLen) WXCZ }l  
{ 48n7<M;I  
int n = -1; Vi<F@ji  
try{ HMVy
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oSavedFile.write(b,nStart,nLen); sjwD x0(7=  
n = nLen; z#\YA]1  
} CG[04y  
catch(IOException e) U t.#h="  
{ Un\ T} c  
e.printStackTrace (); vABUUAo!Jr  
} [PL]!\NJ  
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return n; %q_b\K  
} ]%I|C++
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} >m8~Fs0  
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/* nsyeid*  
**SiteInfoBean.java ,nz3S5~  
*/ _vr;cjMI  
package NetFox; w4j,t  
v}BXH4&Y  
_/cL"Wf  
public class SiteInfoBean { FP9FE `x  
i=X B0-  
< <]uniZ\  
private String sSiteURL; //Site's URL !MQVtn^C#  
private String sFilePath; //Saved File's Path 9O
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private String sFileName; //Saved File's Name n ?+dX^j  
private int nSplitter; //Count of Splited Downloading File (5Sv$Xt  
t BKra  
l[M?"<Ot;  
public SiteInfoBean() x`VA3nE9  
{//nSplitter的缺省值为5 hO0g3^  
//default value of nSplitter is 5 K#4Toc#=V  
this("","","",5); 6;#Rd|  
} x$=""?dd  
*1CZRfWI  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) hvOl9W>
 
{ <-F[q'!C1  
sSiteURL= sURL; R/?ZbMn]!  
sFilePath = sPath; !\/J|~XZ  
sFileName = sName; ^Bu55q  
this.nSplitter = nSpiltter; ~dlp
oT  
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L}\~)  
} Ym$=^f]-  
^2-t|E=  
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public String getSSiteURL() !
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{ i4H,Ggb  
return sSiteURL; BSHtoD@e7  
} R;`C;Rbf  
%)p?&_  
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public void setSSiteURL(String value) 8KHT"uc'*J  
{ K| '`w.  
sSiteURL = value; Ji7<UJ30x  
} YK%rTbB(  

,WQg.neOA  
$ uqB.f$  
public String getSFilePath() i:\|G^h  
{ <Xl/U^B  
return sFilePath; 8=,-r`oNy  
} `PS>"-AY2  
5dkXDta[G  
l' 2C/#8F  
public void setSFilePath(String value) ?3a:ntX h  
{ 2./;i>H[u  
sFilePath = value; ]3]=RuQK2  
} MZ"|Jn  
jchq\q)_z  
#dDM "s  
public String getSFileName() 7mtX/w9  
{ ED^0t  
return sFileName; 9A ?)n<3d  
} :s>x~t8g#n  
x4-_K%  
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public void setSFileName(String value) 6os{q`/Q])  
{ Kjt\A]R%  
sFileName = value; ?}"39n  
} #Fz/}lO  
fs0EbVDF  
OxqkpK&  
public int getNSplitter() Mh~E]8b  
{ 45;ey }8  
return nSplitter; wEC,Mbn  
} M< /
 
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8p_6RvG  
public void setNSplitter(int nCount) pv]" 2'aQ  
{ uR6 `@F  
nSplitter = nCount; ZQ{-6VCjl  
} Y`rli  
} ||4
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mM.YZUX  
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/* b_^y Ke^W  
**Utility.java GglGFXOL-  
*/ @MO/LvD  
package NetFox; 8QMib3p  
-\n%K
  
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public class Utility { K/K|[=bl  
)+|Y;zC9  
6ZfL-E{  
public Utility() H$.K   
{ VS>xvF  
^h^.;Iqr=  
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} &f2:aT)  
,Oe:SZJ>  
//线程睡眠 ~LQzt@G4  
public static void sleep(int nSecond) me@)kQ8M  
{ E+lr{~  
try{ Bj<s!}i{[  
Thread.sleep(nSecond); dz!m8D0  
} G.`
},c;A-  
catch(Exception e) p6!5}dD(  
{ Ft38)T"2R\  
e.printStackTrace (); fUr%@&~l^  
} LI].*n/v  
} t<o7 S:a"  
'6; {DX  
//日志 o(4gh1b%  
public static void log(String sMsg) 05g %5vHF  
{ U.X`z3q
 
System.err.println(sMsg); 5z =}o/?  
} ka6E s~  
[!4xInS  
FPH2dN  
public static void log(int sMsg) (cyvE}g  
{ z%#-2&i  
System.err.println(sMsg); fp*6Dv_  
} M\-[C!h,  
}
< Sgc6>)  
%}e['d h  
uVKe?~RC  
/* bN7m[GRO.  
**TestMethod.java <bb!BS&w  
*/ YC')vv3o(  
package NetFox; +Gg|BTTL/  
4wkv#vi7!-  
x;<0Gg~jB  
public class TestMethod { z~3GgR"1d  
:;eQ*{ `\  
Arm'0)B>  
public TestMethod() ;i\N!T{>  
{ ///xx/weblogic60b2_win.exe oyr b.lu/  
try{ (xHu@l!]  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ~^jPE)  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); g$^-WmX\m  
SiteFileFetch fileFetch = new SiteFileFetch(bean); {kw%7}!  
fileFetch.start(); wU>Fz*  
} KE ?NQMU  
catch(Exception e){e.printStackTrace ();} yQMwt|C4  
e5 L_<V^Jo  
!Ve0:$  
} r{^43
g?  
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public static void main(String[] args) T[)!7@4r  
{ 8toOdh  
new TestMethod(); &R?`QB2/  
} W#~7X  
} *Z^`H!&  
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