http断点续传简单实现（java)

/* Wa>}wA=v  
**SiteFileFetch.java K^)Eb(4  
*/ Z!a=dnwHz  
package NetFox; ~k-y &<UR  
import java.io.*; T*/rySs  
import java.net.*; XB;7!8|  
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public class SiteFileFetch extends Thread { xf\C|@i  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 4$HhP,gL=  
long[] nStartPos; //开始位置 ) yi E@ X  
long[] nEndPos; //结束位置 <Uk}o8E  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 P-9)38`5  
long nFileLength; //文件长度 kr^P6}'  
boolean bFirst = true; //是否第一次取文件 q5J5>  
boolean bStop = false; //停止标志 Gt8M&S-;  
File tmpFile; //文件下载的临时信息 xjUT{iwS  
DataOutputStream output; //输出到文件的输出流 |#v7/$!  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） D#9m\o_  
public SiteFileFetch(SiteInfoBean bean) throws IOException ?um;s-x)  
{ ]!W=^!  
siteInfoBean = bean; ihhDOmUto  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); U|H=Y"pL  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 6##_%PO<m  
if(tmpFile.exists ()) ;0]aq0_#(  
{ xk9%F?)
 
bFirst = false; IEL%!RFG  
read_nPos(); 6fE7W>la  
} [t m_Mg  
else bi',j0B  
{ :;%2BSgFU  
nStartPos = new long[bean.getNSplitter()]; +[6G5
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nEndPos = new long[bean.getNSplitter()]; i<C*j4qQ  
} <yV"6/l0  
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} ih-#5M@  
gMi
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//up5R_nx  
public void run() kYE9M8s;  
{ >4x(e\B  
//获得文件长度 { T/[cu<  
//分割文件 T= 80,  
//实例FileSplitterFetch \i>?q  
//启动FileSplitterFetch线程 Fk&c=V;SU  
//等待子线程返回 x /(^7#u,  
try{ 2lZ Q)  
if(bFirst) u74[>^  
{ `z}?"BW|  
nFileLength = getFileSize(); hE:9{;Gf  
if(nFileLength == -1) ;}I:\P  
{ 
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System.err.println("File Length is not known!"); 2"v6 >b%  
} >>4qJ%bL  
else if(nFileLength == -2) +)AG*  
{ aL\PGdgO  
System.err.println("File is not access!"); C!O0xhs  
} %:f&.@'r  
else LRxZcxmy  
{ MVpGWTH@F  
for(int i=0;i<nStartPos.length;i++) ~p6 V,Q  
{ u4cnE"  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); &C5_g$Ma.Z  
} +zqn<<9  
for(int i=0;i<nEndPos.length-1;i++) 7uqzm  
{ B&M%I:i  
nEndPos = nStartPos[i+1]; SBu"3ym  
} $j%'{)gK  
nEndPos[nEndPos.length-1] = nFileLength; L]|gZ&^  
} n1ZbRV  
} (!u~CZ;  
^cC,.Fdw  
^'MT0j  
//启动子线程 93>jr<A  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; *g"Nq+i@  
for(int i=0;i<nStartPos.length;i++) 1/B>XkCJ  
{ /s&9SYF  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), tn\yI!a  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), -vo})lO  
nStartPos,nEndPos,i); PudS2k_Qv  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); fCd&D  
fileSplitterFetch.start(); @Rze| T.  
} ;J( 8 L  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), V;VHv=9`o  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 3Y4?CM&0v  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 94`7a<&ZNL  
nEndPos = " + nFileLength); LtF,kAIt7v  
// fileSplitterFetch[nPos.length-1].start(); #FLb*%Nr  
@}u*|P*  
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//等待子线程结束 AEI>\Y  
//int count = 0;
oN~&_*FE  
//是否结束while循环 T3.&R#1M8-  
boolean breakWhile = false; caR<Kb:;*  
,$L4dF3  
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while(!bStop) ='r!g  
{ f
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write_nPos(); ;vR4XHl|  
Utility.sleep(500); un"Gozmt5  
breakWhile = true; #6aW9GO  
4}baSV  
?T8}K>a   
for(int i=0;i<nStartPos.length;i++) +zN-!5x  
{ IJp-BTO{V  
if(!fileSplitterFetch.bDownOver) dh\'<|\K  
{ G^|:N[>B  
breakWhile = false; .[KrlfI  
break; m]0;"jeL  
} A/$QaB,x  
} e`_LEv  
if(breakWhile) ;W )Y OT  
break; ij`w} V  
MTh<|$   
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//count++; 2eS~/Pq5=i  
//if(count>4) =!A_^;NQf  
// siteStop(); %g$o/A$  
} \A#41  
Q~]uC2Mw  
?3`UbN:  
System.err.println("文件下载结束！"); :K,i\  
} T@B/xAq5!  
catch(Exception e){e.printStackTrace ();} U[-o> W#  
} 9MJG;+B~  
H [\o RId  
oG?Xk%7&\  
//获得文件长度 _Kf%\xg  
public long getFileSize() 3AtGy'NTp  
{ q-2Bt,Y  
int nFileLength = -1; ]IQ&>z}<  
try{ YQvD|x  
URL url = new URL(siteInfoBean.getSSiteURL()); V#$RR!X'  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); A2Ed0|By  
httpConnection.setRequestProperty("User-Agent","NetFox"); ',@3>T**  
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int responseCode=httpConnection.getResponseCode(); >Eto( y"q  
if(responseCode>=400) K#d`Hyx  
{ ;?iW%:_,  
processErrorCode(responseCode); %3-y[f  
return -2; //-2 represent access is error Np9<:GF1  
} zrgk]n;Pq  
BoWg0*5xb  
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String sHeader; R4cM%l_#W  
~L\z8[<C  
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for(int i=1;;i++) &i6mW8l  
{ n0 {i&[I~+  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 9wwqcx)3(  
//Utility.log(in.readLine()); '[:D$q;  
sHeader=httpConnection.getHeaderFieldKey(i); ~rKrpb]ow  
if(sHeader!=null) D?_Zl;bQ'^  
{ 
4N3R|  
if(sHeader.equals("Content-Length")) 5coyr`7mP  
{ VA_PvL.9  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); }!r|1$,kL  
break; <{cQM$#  
} \'D0'\:vz  
} !CT5!5T  
else Qd$nH8EDY  
break; Ya"a`ozq  
} =s2*H8]  
} osAd1<EI
C  
catch(IOException e){e.printStackTrace ();} f}f9@>.  
catch(Exception e){e.printStackTrace ();} >*_$]E  
4F'LBS]=0  
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Utility.log(nFileLength); 266h\2t6  
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return nFileLength; g|yvF-+  
} xF'EiX~  
E A1?)|}n  
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//保存下载信息（文件指针位置） ]72`};  
private void write_nPos() *zvx$
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{ (exa<hh  
try{ b9HtR-iR;  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 6j]0R*B7`Q  
output.writeInt(nStartPos.length); m8hk:4Ae  
for(int i=0;i<nStartPos.length;i++) g7`LEF <A  
{  w``ST  
// output.writeLong(nPos); <)c)%'v  
output.writeLong(fileSplitterFetch.nStartPos); 9IfmW^0  
output.writeLong(fileSplitterFetch.nEndPos); ;))+>%SGCt  
} c9u`!'g`i  
output.close(); K!Y71_#  
} Yu^4VXp~M%  
catch(IOException e){e.printStackTrace ();} ~Otoqu|  
catch(Exception e){e.printStackTrace ();} ,f'CD{E  
} 9F;>W ET  
6}Ci>_i4#  
37.S\gO]  
//读取保存的下载信息（文件指针位置） K;H&n1  
private void read_nPos() YfKdR"i+.  
{ 8^+%I/S$  
try{ qWPkT$ u  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); rcG"o\g@+  
int nCount = input.readInt(); ,m|h<faZL
 
nStartPos = new long[nCount]; 'yEHI  
nEndPos = new long[nCount]; LYK"(C  
for(int i=0;i<nStartPos.length;i++) }!.(n=idZ  
{ YZ8>OwQz2  
nStartPos = input.readLong(); 0-Ku7<a  
nEndPos = input.readLong(); O;jrCB  
} (v
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input.close(); /%1ON9o>  
} 2-v%`fA  
catch(IOException e){e.printStackTrace ();} !PQ<04jA!  
catch(Exception e){e.printStackTrace ();} y/7\?qfTk  
} xdt- ;w|  
Q\7h`d%)  
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private void processErrorCode(int nErrorCode) vr6w^&[c^  
{ Y)2,PES=  
System.err.println("Error Code : " + nErrorCode); p]+Pkxz]'  
} >@_^fw)  
pO3SUOP  
Kn;"R:  
//停止文件下载 I-(zaqp@  
public void siteStop() SZ'R59Ee<  
{ flbd0NB  
bStop = true; ;$wVu|&  
for(int i=0;i<nStartPos.length;i++) !?h;wR  
fileSplitterFetch.splitterStop(); >SHhAEF  
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?1 4{J]H4  
} K Z91-  
} n 0L^e  
//负责部分文件的抓取 /7F:T[  
**FileSplitterFetch.java _Q4)X)F  
*/ dcN22A3  
package NetFox; %l[( Iw  
E]-/Zbvdv  
>}i E(  
import java.io.*; &B1WtW
 
import java.net.*; bK&+5t&  
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public class FileSplitterFetch extends Thread { OA;XiR$xP  
Ai3*QX  
I,vJbvvl!  
String sURL; //File URL }WXi$(@v  
long nStartPos; //File Snippet Start Position ENs&RZ;  
long nEndPos; //File Snippet End Position ( ^Nz9{  
int nThreadID; //Thread's ID VuZuS6~#J  
boolean bDownOver = false; //Downing is over ]&+s6{}  
boolean bStop = false; //Stop identical YUy0!`!`  
FileAccessI fileAccessI = null; //File Access interface DsCcK3 k  
+VOK%8,p  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException JP[K;/  
{ y}ev ,j  
this.sURL = sURL; >U27];}y  
this.nStartPos = nStart; fJ!R6D  
this.nEndPos = nEnd; fuf"Ae  
nThreadID = id; )zdQ1
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fileAccessI = new FileAccessI(sName,nStartPos);//定位 Bn&ze.F  
} n9ej7
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public void run() hT+_(>hT  
{ VTY 5]|;  
while(nStartPos < nEndPos && !bStop) .Vvx
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{ S3Xl  
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try{ {fT6O&br  
URL url = new URL(sURL); srrgvG,  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); z5*'{t)  
httpConnection.setRequestProperty("User-Agent","NetFox"); u <v7;dF|s  
String sProperty = "bytes="+nStartPos+"-"; ?J>  
httpConnection.setRequestProperty("RANGE",sProperty); 7?w*]  
Utility.log(sProperty); 6q.Uhe_B  
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InputStream input = httpConnection.getInputStream(); F0Yd@Lk$_  
//logResponseHead(httpConnection); dJNe+ MB`  
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byte[] b = new byte[1024]; ^9:Z7 >Z  
int nRead; 59;KQ  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) wgGl[_)  
{ Y\g3hM  
nStartPos += fileAccessI.write(b,0,nRead); pG;U2wE  
//if(nThreadID == 1) 3"~!nn0;  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 07{)?1cod4  
} |z^^.d~a0  
.V8La
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Utility.log("Thread " + nThreadID + " is over!"); <*cikXS  
bDownOver = true; &`2)V;t  
//nPos = fileAccessI.write (b,0,nRead); 8$Y9ORs4  
} lA8`l>I  
catch(Exception e){e.printStackTrace ();} di )L[<$DY  
} :P0mx  
} -r]W  
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oE]QF.n#  
//打印回应的头信息 AFE~ v\Gz  
public void logResponseHead(HttpURLConnection con) d<P\&!R(  
{ NyNXP_8  
for(int i=1;;i++) ' %o#q6O  
{ WX3-\Y5E  
String header=con.getHeaderFieldKey(i); 8[{ Vu0R  
if(header!=null) @GW#&\yM  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); g}(L;fy>7  
Utility.log(header+" : "+con.getHeaderField(header)); !%%6dB@%t  
else Se =`N  
break; *VxgARIL  
} i?^L/
b`H  
} =U?dbSf1*  
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public void splitterStop() <frutU16\  
{ ; kI134i=  
bStop = true; ge8ZsaiU  
} amY!qg0P*  
{&1/V  
PB\x3pV!}  
} u.xnOcOH!  
s
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sD#.Oq4&]y  
/* oW6XF-yM  
**FileAccess.java 40m-ch6Q  
*//文件访问(定位，写) ^Xh^xL2cn  
package NetFox; c'yxWZEv  
import java.io.*; C1 *v,i  
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t
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public class FileAccessI implements Serializable{ XU(eEnmom  
ePo}y])2  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 {9q4)R}G  
RandomAccessFile oSavedFile; k~nBiV  
long nPos; k~w*W X'  
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public FileAccessI() throws IOException r\^b(rNe  
{ %n9aaoD  
this("",0); JIq=* '  
} $yNS pNmT0  
o!A+&{  
E hMNap}5"  
public FileAccessI(String sName,long nPos) throws IOException z-)O9PV  
{ 1yu4emye4  
oSavedFile = new RandomAccessFile(sName,"rw"); [`7ThHX  
this.nPos = nPos; 20Wg=p9L  
oSavedFile.seek(nPos); sd|).;s}  
} 1p=]hC  
qY!Zt_Be6  
HN|%9{VeB  
public synchronized int write(byte[] b,int nStart,int nLen)
& >fQp(f  
{ _.8S&  
int n = -1; <7jW_R@  
try{ 8bld3p"^  
oSavedFile.write(b,nStart,nLen); ~b8]H|<'Y  
n = nLen; P/_['7  
} j&qub_j"xX  
catch(IOException e) }*]-jWt1J\  
{ gRcQt:  
e.printStackTrace (); II,8O  
} KPUV@eQ,  
{
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return n; EXqE~afm2  
} }0Ed]  
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b d!Y\OD
  
} },-H"Qs  
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/* hp|YE'uYT  
**SiteInfoBean.java 5:_}zu|!u  
*/ e+fN6v5pU  
package NetFox; 1bwOmhkS  
^^ixa1H<  
' S/gmn  
public class SiteInfoBean {
fe_5LC"  
3%b6{ie/=  
GnJt0{  
private String sSiteURL; //Site's URL G]&qx`TBK  
private String sFilePath; //Saved File's Path }Jj}%XxKs  
private String sFileName; //Saved File's Name nAlQ7'  
private int nSplitter; //Count of Splited Downloading File
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AH~E)S  
R.<g3"Lm>  
public SiteInfoBean()  rjnrju+  
{//nSplitter的缺省值为5 e$Pj.>-<=  
//default value of nSplitter is 5 \ @2R9,9E  
this("","","",5); +ami?#Sz*;  
} "E4a=YH_  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) \:LW(&[!  
{ $6R-5oQ  
sSiteURL= sURL; 5]:U9ts#  
sFilePath = sPath; }i&/G+_  
sFileName = sName; JNnDts*w  
this.nSplitter = nSpiltter; &mS^ZyG  
e~"U @8xk~  
;#< 0<  
} 19%imf  
\1M4Dl5!  
0?|<I{z2  
public String getSSiteURL() NL+N%2XG7  
{ wi{3/  
return sSiteURL; !0<,@v"  
} 44j*KsBf  
SiN0OB  
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public void setSSiteURL(String value) h^P#{W!e\  
{ )Hr`MB  
sSiteURL = value; YKK*ER0  
} &s!@29DXR  
2=!RQv~%  
m+z&Q  
public String getSFilePath() )J(6xy  
{ /Z}}(6T  
return sFilePath; +D*Z_Yh6  
} >9Vn.S  
}4X0epPp;:  
]7c=PC  
public void setSFilePath(String value) r
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{ :NTO03F7v  
sFilePath = value; `N8O"UcoBo  
} #}5uno  
FW DNpr  
}"%N4(Kd  
public String getSFileName() * kh tJ]=  
{ 6j|{`Zd)G  
return sFileName; j3ls3H&  
} 0jWVp-y  
4E}Yt$|  
-m
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public void setSFileName(String value) SUK?z!f<i  
{ lPAQ3t!,  
sFileName = value; =($xG#g`  
} ,|/f`Pl  
cPQiUU~W@  
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public int getNSplitter() 86a\+Kz%%L  
{ W[r>.7>?h  
return nSplitter; '$+ogBS  
} W\V.r$? v  
sNFlKQ8)Q  
$<[79al#  
public void setNSplitter(int nCount) 4s oJ.j8  
{ *lJxH8\  
nSplitter = nCount; J]r^W)O  
} bpa?C  
} <(!:$  
&5!8F(7  
ZSo)  
/*  e]$s t?  
**Utility.java o^wqFX(Y  
*/ tfWS)y7  
package NetFox; %\:Wi#w>  
dqcL]e  
@>7%qS  
public class Utility { `">=  
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%B?=q@!QWn  
public Utility() iH'p>s5L  
{ iK;XZZ(  
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} _)iCa3z  
IdN41  
//线程睡眠 U #0Cx-E  
public static void sleep(int nSecond) 0PCGDLk8  
{ \z)%$#I  
try{ K:WDl;8(d  
Thread.sleep(nSecond); 62NsJ<#>  
} PQE=D0  
catch(Exception e) DVeE1Q  
{ A]3k4DLYS  
e.printStackTrace (); \GU<43J2uo  
} b\5F]r  
} !bP@n  
{K!)Ss  
//日志 TkF[x%o  
public static void log(String sMsg) bW:!5"_{H  
{ IAyp2  
System.err.println(sMsg); >@Kx>cg+  
} 5IpDeJ$  
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9jGu}Vo  
public static void log(int sMsg) -F3-{E  
{ EiaW1Cs  
System.err.println(sMsg); wdoR
%b{M  
} dgP3@`YS  
} #p{4^  
uEx-]F  
YchH~m
|  
/* ?r!o~|9|  
**TestMethod.java [<TrS/,)>  
*/ "EJ~QCW*Yh  
package NetFox; -ze J#B)C  
x|29L7i  
CU~PT.  
public class TestMethod { Kf
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7x8 yxE  
7PF%76TO  
public TestMethod() 51.%;aY~z  
{ ///xx/weblogic60b2_win.exe 5E <kwi  
try{ :fJN->wY^s  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); [KQ6Ta.  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); rW#T vUn  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ,iwp,=h=  
fileFetch.start(); IUct  
} EBmt9S
 
catch(Exception e){e.printStackTrace ();} ;GD]dW#  
8JUwf  
4`=mu}Y2  
} |+"(L#wk  
]{>,rK[So  
%xt^698&X  
public static void main(String[] args) 3=;<$+I6  
{ R/a*LSe@&  
new TestMethod(); (4-CF
3D  
} CTA3*Gn  
} cl/_JQ&  
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