http断点续传简单实现（java)

/* j0Id!o  
**SiteFileFetch.java tj`tLYOZ@-  
*/ (K!M*d+  
package NetFox; qQwJJjf  
import java.io.*; MHC.k=  
import java.net.*; };4pZceV  
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{Q}!NkF1  
public class SiteFileFetch extends Thread { .~FKyP>[$  
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SiteInfoBean siteInfoBean = null; //文件信息Bean "it`X B.  
long[] nStartPos; //开始位置 nL "g23  
long[] nEndPos; //结束位置 yBUZVqqDa  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Lg\8NtP  
long nFileLength; //文件长度 R (+h)#![  
boolean bFirst = true; //是否第一次取文件 =*@MQ  
boolean bStop = false; //停止标志 g6x/f<2x  
File tmpFile; //文件下载的临时信息 B<vvsp\X  
DataOutputStream output; //输出到文件的输出流 [flu|v  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） `</=AY>  
public SiteFileFetch(SiteInfoBean bean) throws IOException cKvAR5|  
{ SaX,^_GY  
siteInfoBean = bean; vWPM:1A  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 1Xk{(G<\  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 60
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if(tmpFile.exists ()) :pL1F)-*  
{ )3D+gu  
bFirst = false; Huc3|~9  
read_nPos(); %RfY`n  
} A1#4nkkc9  
else Mm:a+T  
{ ntA[[OIFO  
nStartPos = new long[bean.getNSplitter()]; 8gu'dG=  
nEndPos = new long[bean.getNSplitter()]; 9XJ9~I?  
} [N0/">c  
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} &"~,V6,q  
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public void run() V
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{ @SF")j|  
//获得文件长度 ur~Tql  
//分割文件 [7SI<xkv  
//实例FileSplitterFetch wt_?B_n
R  
//启动FileSplitterFetch线程 1A)wbH)  
//等待子线程返回 ^G7n#  
try{ #V(Hk )  
if(bFirst) 
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{ ~,`\D7Z3  
nFileLength = getFileSize(); w'5dk3$"  
if(nFileLength == -1) (A
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{ 8+g|>{Vov  
System.err.println("File Length is not known!"); {8>_,z^P)  
} ShsP]$Yp  
else if(nFileLength == -2) /%}YuN  
{ 7Da^Jv k  
System.err.println("File is not access!"); ;|2;kvf"w  
} n_!]B_Vd$  
else o}AqNw60v  
{ zYgK$u^H  
for(int i=0;i<nStartPos.length;i++) =Y=^]ayO/  
{ ]mJAKycE%  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); EiIFVP   
} +~pc%3*  
for(int i=0;i<nEndPos.length-1;i++) t6,M  
{ [jtj~]&mO  
nEndPos = nStartPos[i+1]; Jz:W-o  
} d= T9mj.@  
nEndPos[nEndPos.length-1] = nFileLength; @gl%A&a  
} gp|7{}Q{  
} U%B]N@  
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eV  
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//启动子线程 5)SZd)  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; exrt|A]_[  
for(int i=0;i<nStartPos.length;i++) MkV*+LXC  
{ hz~CW-47  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), S;AnpiBM8  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), k~s>8N:&G  
nStartPos,nEndPos,i); k @/SeE  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); XtH_+W+O  
fileSplitterFetch.start(); 8Q)mmkI\=  
} %>z8:oJ
 
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Uub%s`O  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); %RD7=Z-z  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Jv{"R!e"P  
nEndPos = " + nFileLength); uL
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// fileSplitterFetch[nPos.length-1].start(); X=c ,`&^  
T[$hYe8%^  
I9j+x])  
//等待子线程结束 D(ntVR  
//int count = 0; 17[t_T&Ak9  
//是否结束while循环 >fzzrD}]  
boolean breakWhile = false; AYQh=$)(  
]B.,7  
 IOES3  
while(!bStop) DBh/V#* D  
{ I8oKa$RF  
write_nPos(); .$s|T  
Utility.sleep(500); PNxO\Rc  
breakWhile = true; H=SMDj)s+  
Wes"t}[25  
3/|{>7]1  
for(int i=0;i<nStartPos.length;i++) % |Gzht\  
{ X|lmH{k
f  
if(!fileSplitterFetch.bDownOver) \U =>  
{ 28qWC~/9  
breakWhile = false; 8P y_Y>  
break; y42T.oK8c  
} ^0?cyv\>LA  
} )^2jsy -/  
if(breakWhile) g<0%-p  
break; MKYE]D;  
8\t7}8f  
XK9*,WA9r  
//count++; R\=\6("  
//if(count>4) R#^pNJN  
// siteStop(); $A0]v!P~i-  
} yT9RNo/w  
-EIMh^  
?@BaBU:o`F  
System.err.println("文件下载结束！"); FHPZQC8  
} M]zNW{Xt  
catch(Exception e){e.printStackTrace ();} qf&
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} 8[P6c;\  
l8Iy03H  
7(iRz  
//获得文件长度 hQLx"R$  
public long getFileSize() f6A['<%o  
{ jl%eO.  
int nFileLength = -1; ?BZ`mrH^  
try{ X1QZEl  
URL url = new URL(siteInfoBean.getSSiteURL()); k#G7`dJl  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); k 5kX  
httpConnection.setRequestProperty("User-Agent","NetFox"); 'Bn_'w~j{  
:hdh$}y  
%lW:8ckL  
int responseCode=httpConnection.getResponseCode(); l{x#*~ga  
if(responseCode>=400) BQmafpp`  
{ pY5HW2TsY|  
processErrorCode(responseCode); @uD{`@[  
return -2; //-2 represent access is error $>37PVVW  
} !/9Sb1_~  
EF{'J8AQ  
<g1hdF0  
String sHeader; yFtf~8s3  
T:5%sN;#O  
siZ_JJW  
for(int i=1;;i++) B{7/A[$%C  
{ 5Jd {Ev  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); hf5SpwxLiH  
//Utility.log(in.readLine()); }n8;A;axi  
sHeader=httpConnection.getHeaderFieldKey(i); ~4gKAD  
if(sHeader!=null) zC;lfy{f=  
{ e[o ;l  
if(sHeader.equals("Content-Length")) ,+evP=(cX  
{ 3Ya6yz  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); hds4_  
break; T1[ZrY'0  
} 7}85o J  
} qnV9TeU)  
else L uKm  
break; [`dipLkr  
} dR{ V,H7N  
} .Sw'Bo!Ee  
catch(IOException e){e.printStackTrace ();} OEi9 )I  
catch(Exception e){e.printStackTrace ();} Qn&^.e9I  
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Utility.log(nFileLength); Bq`kVfx  
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return nFileLength; GQWTQIl
]  
} W4Q]<<6&  
rJj~cPwL"  
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//保存下载信息（文件指针位置） yt,;^o^  
private void write_nPos() (LPD  
{ YNk|UwJi  
try{ >*CK@"o  
output = new DataOutputStream(new FileOutputStream(tmpFile)); - mXr6R?  
output.writeInt(nStartPos.length); 54%}JA][  
for(int i=0;i<nStartPos.length;i++) 4+bsG6i  
{ ~cwwB{  
// output.writeLong(nPos); )Cfrqe1^  
output.writeLong(fileSplitterFetch.nStartPos); Lcm!e  
output.writeLong(fileSplitterFetch.nEndPos); ??Ac=K\  
} 9B0"GEwrs  
output.close(); F tjm@:X  
} 5!*a,$S  
catch(IOException e){e.printStackTrace ();} px@\b]/  
catch(Exception e){e.printStackTrace ();} < Ifnf6~  
} m,O!Mt  
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t68RWzqiG[  
//读取保存的下载信息（文件指针位置） (7,Awf5D~  
private void read_nPos() p
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{ #CmBgxg+M  
try{ v^'~
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DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 2=EKAg=S  
int nCount = input.readInt(); ]+P&Y:  
nStartPos = new long[nCount]; |e>-v  
nEndPos = new long[nCount]; *E'K{?-K  
for(int i=0;i<nStartPos.length;i++) t;3.;  
{ c2/HY8ttRD  
nStartPos = input.readLong(); RkzBn  
nEndPos = input.readLong(); ibyA~YUN/  
} ,jmG!qJb  
input.close(); I"4B1g  
} IIkJ"Qg.  
catch(IOException e){e.printStackTrace ();} v!Z9T  
catch(Exception e){e.printStackTrace ();} 5@ug1F&  
} 3I+pe;  
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private void processErrorCode(int nErrorCode) (6nw8vQ  
{ tw66XxE  
System.err.println("Error Code : " + nErrorCode);
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-&  
} Ay]5GA!W+  
& j43DYw4  
'S"F=)*-  
//停止文件下载 tUQ)q  
public void siteStop() hh9{md\  
{ S

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bStop = true; j
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for(int i=0;i<nStartPos.length;i++) VzesqVx  
fileSplitterFetch.splitterStop(); q]x@q  
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|k+^D:  
} jPfoI-  
} o9i\[Ul  
//负责部分文件的抓取 h.*|4;  
**FileSplitterFetch.java 8T4J^6  
*/ 8{C3ijR  
package NetFox; rAKdf??  
c+JlM1p@  
q)*0G*  
import java.io.*; \IKr+wlN8  
import java.net.*; PO&`rr  
/03>|Juo  
:R)IaJ6)  
public class FileSplitterFetch extends Thread { \cG'3\GI  
Nu'rn*Y_  
|NI0zd  
String sURL; //File URL <  -Nj  
long nStartPos; //File Snippet Start Position Gkl#s7'  
long nEndPos; //File Snippet End Position &kG<LGXP#  
int nThreadID; //Thread's ID z?PF9QL1  
boolean bDownOver = false; //Downing is over Z(L>~+%  
boolean bStop = false; //Stop identical :|a[6Uwl\V  
FileAccessI fileAccessI = null; //File Access interface gP3[=a"\  
y{&,YV&_h  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ;>~iCFk]?  
{ ?CIa)dhu  
this.sURL = sURL; @:63OLlrG  
this.nStartPos = nStart; %^S1 fUwT  
this.nEndPos = nEnd; n#*cVB81  
nThreadID = id;
*$QUE0  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 7P  
} fc91D]c  
O'k"6sBb  
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public void run() i|t$sBIh  
{ t?
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while(nStartPos < nEndPos && !bStop) v[m>;Ubg&  
{ [Y[|:_+5  
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?IK[]=!  
try{ u URf  
URL url = new URL(sURL); t4h* re+  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); d/MMPge3  
httpConnection.setRequestProperty("User-Agent","NetFox"); [Mx+t3M  
String sProperty = "bytes="+nStartPos+"-"; R8HFyP  
httpConnection.setRequestProperty("RANGE",sProperty); hQ9VcS6=gD  
Utility.log(sProperty); qg_=5s  
=vR>KE  
IMj{n.y4  
InputStream input = httpConnection.getInputStream(); B9]KC i
 
//logResponseHead(httpConnection); B{44|aq1|  
7z}NI,R}1  
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byte[] b = new byte[1024]; 8{AzB8xp  
int nRead; Lx.X#n.]T  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) KyjN'F$  
{ 2gA6$s7  
nStartPos += fileAccessI.write(b,0,nRead); ./u3z|q1  
//if(nThreadID == 1) % _N-:.S  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); \j4TDCs_[  
} =m UtBD.;  
\]zHM.E1  
BV|LRB}G  
Utility.log("Thread " + nThreadID + " is over!"); W_%Dg]l   
bDownOver = true; [S4<bh!  
//nPos = fileAccessI.write (b,0,nRead); Wh,p$|vL  
} +5voAx!  
catch(Exception e){e.printStackTrace ();} EsdA%`  
} ->d3FR  
} alyWp  
+ps(9O/B>  
/@:I\&{f'9  
//打印回应的头信息 b}WU  
public void logResponseHead(HttpURLConnection con) Tv!zqx#E  
{ d-y8c  
for(int i=1;;i++) EW]rD  
{ 12.|Ed*72  
String header=con.getHeaderFieldKey(i); `KB;3L  
if(header!=null) U<K)'l6#2n  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 9J*.'Y  
Utility.log(header+" : "+con.getHeaderField(header));  (cx Q<5  
else iU+O(vi  
break; F P3{Rp  
} ;ry~x:7L7  
} kZ$2Uss  
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public void splitterStop() \8g'v@$wG  
{ %py3fzg  
bStop = true; #A\@)wJ  
} {OIB/  
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} a5caryZ"z  
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/* ||D PIn]  
**FileAccess.java x n?$@  
*//文件访问(定位，写) CVE(N/&b  
package NetFox; R"W5R-  
import java.io.*; xIA]5@;a  
#zRHYZc'T|  
ncrg`<'/,  
public class FileAccessI implements Serializable{ 6%it`A8}  
BMug7xl"  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 0CO@@`~4  
RandomAccessFile oSavedFile; .dI".L  
long nPos; __!LTpp  
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public FileAccessI() throws IOException FY<Q|Ov  
{ ]"}BqS0  
this("",0); <?s@-mpgN  
} KRz~3yH{c  
Qk? WX (`B  
yIhPB8QL  
public FileAccessI(String sName,long nPos) throws IOException !wN2BCSY@  
{ ; [G:  
oSavedFile = new RandomAccessFile(sName,"rw"); ? X6M8`  
this.nPos = nPos; O}>@G  
oSavedFile.seek(nPos); R2v9gz;W  
} XLC9B3Jt  
)X?oBNsj  
1RJFPv  
public synchronized int write(byte[] b,int nStart,int nLen) M!+
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{ 

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int n = -1; )X-'Q-  
try{ sC.b'1P  
oSavedFile.write(b,nStart,nLen); Da615d  
n = nLen; EjL]#,QR  
} )by7[I0v  
catch(IOException e) yUj`vu2  
{ -nXP<v=V  
e.printStackTrace (); V:w%5'^3  
} _aR{B-E   
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return n;  q[_qZ  
} pd:7K'yaw  
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"Yh;3tI4*  
} @oE 5JM  
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/* 
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**SiteInfoBean.java 9T;4aP>6j#  
*/ #h?IoB7  
package NetFox; (oi:lC@h*  
!{g<RS(c  
HwHF8#D*l  
public class SiteInfoBean { >=[uLY[aK  
lFGuQLuqA{  
=..Bh8P71!  
private String sSiteURL; //Site's URL =SXdO)%2  
private String sFilePath; //Saved File's Path bZNqv-5 4h  
private String sFileName; //Saved File's Name zMR)w77  
private int nSplitter; //Count of Splited Downloading File i
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!HvA5'|:}  
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public SiteInfoBean() UDHWl_%L  
{//nSplitter的缺省值为5 {Sf[<I  
//default value of nSplitter is 5 8@t8P5(vL  
this("","","",5); A`n>9|R  
} ,X.[37  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) IMkE~0x4</  
{ Zz0bd473k?  
sSiteURL= sURL; CRK%^3g  
sFilePath = sPath; <E2 IU~e  
sFileName = sName; fB8, )&  
this.nSplitter = nSpiltter; ZwkUd-=0i  
=rA?,74  
.
/#Y
UIC  
} +<a\0FsD  
8K,X3a9  
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public String getSSiteURL() P_(8+)ud-  
{ ;P91'B~
t  
return sSiteURL; /65YHXg,  
} ^

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#EH=tJgO|J  
.PB!1C.}@  
public void setSSiteURL(String value) IRN,=  
{ MgeC-XQM  
sSiteURL = value; YnEyL2SuU  
} I0m7;M7 P  
K!6T8^JH  
Q
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public String getSFilePath() wlXs/\es  
{ -8 uS#  
return sFilePath; M& ZKc
 
} bf_ >?F^  
sY;h~a0n  

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public void setSFilePath(String value) 287j,'vR  
{ $gl|^
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sFilePath = value; s<!A<+Sh  
} V'kB
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Qc7*p]E&  
public String getSFileName() v3DK0MW  
{ w|f+OlPXq  
return sFileName; 7h\is  
} p/{%%30ke  
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public void setSFileName(String value) Ichg,d-M-K  
{ hi(b\ABx  
sFileName = value; 7J);{ &x9h  
} QD-\'Bp/X  
\'2rs152  
JG;}UuHYM  
public int getNSplitter() WO>,=^zPJ  
{
W>TG?hH  
return nSplitter; (-S^L'v62v  
} kXL0  
q]4h#?.-1v  
/`M#  
public void setNSplitter(int nCount) |sGJum&=  
{ w[GEm,ZC  
nSplitter = nCount; x_3B) &9  
} ./I?|ih  
} OG{*:1EP  
3FvVM0l"  
! VT$U6  
/* s17)zi,?4  
**Utility.java T`^Jws{;7  
*/ O1\4WG%  
package NetFox; +o@:8!IM1  
R?1Z[N  
TFOx=_.%i  
public class Utility { -~c-mt  
=oVC*b  
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public Utility() 8AW}7.<5  
{ Rk5#5R n  
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2c]751
  
} i+(>w'=m  
Y*#xo7#B  
//线程睡眠 xq.kH|bH  
public static void sleep(int nSecond) 'Ev[G6vo  
{ }8AH/  
try{ PK|qiu-O&*  
Thread.sleep(nSecond); 4IW fp&Q!  
} oAifM1*0  
catch(Exception e) k>i`G5Dh  
{ \A^8KVE!  
e.printStackTrace (); khjdTq\\  
} [^GBg>k  
} :YRHO|  
X9PbU1o;  
//日志 {Y/0BS2D  
public static void log(String sMsg) %h(%M'm?  
{ 9:g A0Z  
System.err.println(sMsg); W\-`}{B_/  
} 3f$n8>mq  
KC&XOI %  
y=pW+$k  
public static void log(int sMsg) |X*y-d77W  
{ G0m$bi=z  
System.err.println(sMsg); 0t7)x8c  
} uO]
|YF  
} CAx$A[f<  
s]e`q4ip  
.Y2H
d$rs  
/* oQpGa>6U&  
**TestMethod.java q|%+?j(  
*/ mW{uChHP  
package NetFox; uX!6:v]  
prt(xr4@  
Ohj^Z&j  
public class TestMethod { -rYb{<;ST  
%CYo, e  
&ZMQ]'&  
public TestMethod() Z3MhHvvgp{  
{ ///xx/weblogic60b2_win.exe $DfK}CT  
try{ 7bbFUUUG"  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); %m/lPL  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); r[^.\&-  
SiteFileFetch fileFetch = new SiteFileFetch(bean); i,"Xw[H*s  
fileFetch.start(); !0? B
=yA  
} #b&tNZ4!_  
catch(Exception e){e.printStackTrace ();} F{QOu0$cA4  
I)#8}[vK  
_1Rw~}O  
} 8a@k6OZ  
"9^b1UH<  
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public static void main(String[] args) xMQ>,nZ  
{ >`&2]Wc)  
new TestMethod(); >&e=0@?+G  
} 9[X'9*,  
} LHx ")H?,  
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