http断点续传简单实现（java)

/* ja>Tnfu  
**SiteFileFetch.java L"b5P2{c  
*/ ?4~lA L1  
package NetFox; QnGJ4F
  
import java.io.*; }M~AkJL  
import java.net.*; ]jYl:41yI  
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public class SiteFileFetch extends Thread { "M*\,IH  
'/p5tw8  
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SiteInfoBean siteInfoBean = null; //文件信息Bean E|fPI u  
long[] nStartPos; //开始位置 G37_ `C  
long[] nEndPos; //结束位置 . }1!MK5  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 BW*zj=N%  
long nFileLength; //文件长度 3~S~)quwP  
boolean bFirst = true; //是否第一次取文件 O0I/^  
boolean bStop = false; //停止标志 "
{:*fI;!  
File tmpFile; //文件下载的临时信息 _6[NYv$"  
DataOutputStream output; //输出到文件的输出流 ~gAx  
}z*p2)v`  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） R`<E3J\*  
public SiteFileFetch(SiteInfoBean bean) throws IOException @F1pu3E  
{ z DK+8  
siteInfoBean = bean; bIhL!Ty T.  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 3wh
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tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info");
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if(tmpFile.exists ()) Ar$LA"vu4  
{ P"#^i<ut@T  
bFirst = false; I'j?
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read_nPos(); }l2JXf55  
} ':[y]ep(~|  
else _8`|KY  
{ 8_LDS  
nStartPos = new long[bean.getNSplitter()]; r#j*vO '  
nEndPos = new long[bean.getNSplitter()]; :=8vy  
} RU'J!-w{  
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} s0h)~z  
0'<S7?~|  
*5NffiA}-  
public void run() _96&P7  
{ JSL3.J  
//获得文件长度 dvf*w:5K!  
//分割文件 8,=$>@u  
//实例FileSplitterFetch BOG )JaDW  
//启动FileSplitterFetch线程 kDKpuA!  
//等待子线程返回 *SW,pHYnLb  
try{ @PI\.y_w  
if(bFirst) F,bl>;{[{  
{ t>[r88v  
nFileLength = getFileSize(); B+<k,ad  
if(nFileLength == -1) Q9'p2@Z  
{ AjS5  
System.err.println("File Length is not known!"); pqe tYu  
} 4M]8po/;  
else if(nFileLength == -2) )<|TEp4r-  
{ N4:'X6u;  
System.err.println("File is not access!"); : ?V;  
} ?-f>zx8O  
else o6r4tpiR5  
{ `#]\Wnp~y  
for(int i=0;i<nStartPos.length;i++) Dn[
1BWM/7  
{ `4=b|N+b"  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); JjmL6(*ui  
} ymzm x$o=  
for(int i=0;i<nEndPos.length-1;i++) S;NXOsSu  
{ HT&0i,`  
nEndPos = nStartPos[i+1]; zxh"@j$?  
} = `^jz}  
nEndPos[nEndPos.length-1] = nFileLength; gr;M  
} NR*SEbUU*  
} >g[W@FhT'k  
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*t_&im%E  
//启动子线程 0D'Wr(U(  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; TU/J]'))C  
for(int i=0;i<nStartPos.length;i++) aPC!M4#  
{ Vo%d;>!G\;  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), H@zk8]_P  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), c;^J!e  
nStartPos,nEndPos,i); pR"qPSv'  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); -db+Y:xUZ  
fileSplitterFetch.start(); z)%1i  
} C gx?K]>y  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), - -G1
H  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); <}%ir,8  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", B /W$RcV  
nEndPos = " + nFileLength); E(@;p%:  
// fileSplitterFetch[nPos.length-1].start(); Q-F9oZ*0  
"7HB3?2>W  
G DV-wPX  
//等待子线程结束 L9T u
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//int count = 0; {9Y'v  
//是否结束while循环 `9ox?|iJ  
boolean breakWhile = false; $<v_Vm?6d  
K288&D|1WU  
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while(!bStop) 0REWbcxd"  
{ sYXS#;|M  
write_nPos(); e@OA>  
Utility.sleep(500); GHy#D]Z  
breakWhile = true; 'T[zh#v>S  
f[IchCwX  
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for(int i=0;i<nStartPos.length;i++) guv@t&;t0  
{ {<kG{i/  
if(!fileSplitterFetch.bDownOver) z(3"\ ^T  
{ akQH+j  
breakWhile = false; vrzX%'  
break; U3}R^W~eb  
} _ ^{Ep/ME=  
} |Z ,G  
if(breakWhile) Q7|13^|C  
break; kre&J  
$1+K}tP  
Q$1K{14I  
//count++; Nd!VR+IZ  
//if(count>4) 0Mg8{  
// siteStop(); F:S,{&jB  
} >K :"[?  
"NU".q  
8(>.^667  
System.err.println("文件下载结束！"); c~xo@[NaS  
} yf)`jPM1<  
catch(Exception e){e.printStackTrace ();} -`OR6jd  
} `a>vPW  
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&._!)al  
//获得文件长度 +ZKhmb!  
public long getFileSize() {yR)}r  
{ A+I&.\QAR  
int nFileLength = -1; J\3} il N  
try{ K//T}-Uub  
URL url = new URL(siteInfoBean.getSSiteURL()); VA'X!(Cv  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ,:4DN&<  
httpConnection.setRequestProperty("User-Agent","NetFox"); t1jlxK  
xXZKj  
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int responseCode=httpConnection.getResponseCode(); |*KS<iHr%  
if(responseCode>=400) "<x~{BN?  
{ ,g_onfY  
processErrorCode(responseCode); u!o]Co>  
return -2; //-2 represent access is error 0j(jJAE.  
} B#"|5  
SDHc[66'  
nKB&|!
 
String sHeader; 87KrSZ  
{~fCqP.2  
Cc)P5\jh  
for(int i=1;;i++) c1kxKxE  
{ ]<gCq/V#  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 
KC:4  
//Utility.log(in.readLine());  YX`=M  
sHeader=httpConnection.getHeaderFieldKey(i); *Ca)RgM  
if(sHeader!=null) JA(fam~{  
{ lt6
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if(sHeader.equals("Content-Length")) UZP6x2:=  
{ _i
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nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); -'[(Uzj  
break; Wi[m`#  
} :z.Y$]F@  
} drKjLo[y  
else 9xn23*Fo  
break; ceZ8}Sh  
} UVc<C 1q  
} 
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}  
catch(IOException e){e.printStackTrace ();} N4mJU'_{  
catch(Exception e){e.printStackTrace ();} s;2/Nc   
+'/}[1q1/T  
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Utility.log(nFileLength); ZuvPDW%  
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] 5v4^mk  
return nFileLength; `n`"g<K)Q  
} 'd#\7J>d  
7TkxvSL X  
^mueFw}\  
//保存下载信息（文件指针位置） ;Q=GJ5`B  
private void write_nPos() PKR $I  
{ }l(m5  
try{ $i:||L^8p  
output = new DataOutputStream(new FileOutputStream(tmpFile)); u'i%~(:$\)  
output.writeInt(nStartPos.length); ;,=h59`  
for(int i=0;i<nStartPos.length;i++) F|?'9s*;6G  
{ EeJqszmH  
// output.writeLong(nPos); j;20JA/b  
output.writeLong(fileSplitterFetch.nStartPos); "6N~2q,SW  
output.writeLong(fileSplitterFetch.nEndPos); ,.jHV  
} K- I\P6R`  
output.close(); #[a"%byTR  
} ) wY!/
&  
catch(IOException e){e.printStackTrace ();} -~\.n  
catch(Exception e){e.printStackTrace ();} 6f?BltFaN  
} 5m^Hi}S_  
4b2mtLn_  
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//读取保存的下载信息（文件指针位置） pAil]f6  
private void read_nPos() 58&{5YpS  
{ E8-fW\!F  
try{ ?#m<\]S<  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); AL]h|)6QpC  
int nCount = input.readInt(); pSQCT  
nStartPos = new long[nCount]; zD2.Q%`IM  
nEndPos = new long[nCount]; n<?SZ^X{,/  
for(int i=0;i<nStartPos.length;i++) T+WZE  
{ m0j|58~  
nStartPos = input.readLong(); =1*%>K  
nEndPos = input.readLong(); hA*Z'.[  
} cRh\USS  
input.close(); C~{NKMeC/m  
} H5Ux.]y  
catch(IOException e){e.printStackTrace ();} .vN%UNu  
catch(Exception e){e.printStackTrace ();} SgpZ;\_  
} >AQ)x  
/z1p/RiX  
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private void processErrorCode(int nErrorCode) C[xJU6z  
{ &^&$!Xmu9  
System.err.println("Error Code : " + nErrorCode); [O7w =  
} {b'}:aMc  
]D LZ&5pv  
v._Egk0  
//停止文件下载 %9T~8L @.  
public void siteStop() SbS$(Gt#Bv  
{ j9URl$T:  
bStop = true; -J"qrp
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for(int i=0;i<nStartPos.length;i++) QSHJmk 6L  
fileSplitterFetch.splitterStop(); N^h|h  
'7Mep ]  
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} <E>7>ZL  
} 5=Kq@[(4  
//负责部分文件的抓取 F1gt3 ae  
**FileSplitterFetch.java eC6>yD6D  
*/ =6cyE  
package NetFox; -(\1r2 Y  
HKTeqH_:  
[x!i* rW3  
import java.io.*; ^^7L"je]g  
import java.net.*; euV$2Fg  
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public class FileSplitterFetch extends Thread { 1l/AKI(!  
4>4V-m\  
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String sURL; //File URL =oE_.ux\  
long nStartPos; //File Snippet Start Position #puQi  
long nEndPos; //File Snippet End Position ih>a~U<  
int nThreadID; //Thread's ID @[MO,J&h  
boolean bDownOver = false; //Downing is over kSB  
boolean bStop = false; //Stop identical + a-wv  
FileAccessI fileAccessI = null; //File Access interface #K=b%;>  
N;-/wip
 
59{;VY81  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException >u=%Lz"J  
{ -7>^ rR V  
this.sURL = sURL; `"a? a5]k  
this.nStartPos = nStart; 1.'(nKoq  
this.nEndPos = nEnd; |DN^NhtE  
nThreadID = id; AL>c:K)qO  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 R'6@n#:  
} j4;Du>obQ  
i@P9EU  
4|[<e-W  
public void run() U/ ?F:QD4  
{
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while(nStartPos < nEndPos && !bStop) tT;8r8@  
{ Wrmgu}q  
3A-*vaySV  
>M?H79fF2s  
try{ Hm>-LOCcl  
URL url = new URL(sURL); 7\mDBG  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); JOBz{;:R{  
httpConnection.setRequestProperty("User-Agent","NetFox"); r5o
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String sProperty = "bytes="+nStartPos+"-"; Iq{o-nq  
httpConnection.setRequestProperty("RANGE",sProperty); -=>sTMWpr  
Utility.log(sProperty); Hx$.9'Oq\Q  
L-#e?Y}$J
 
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InputStream input = httpConnection.getInputStream(); j!YNg*H  
//logResponseHead(httpConnection); O!;H}{[dg  
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byte[] b = new byte[1024]; 0|g[o:;fl_  
int nRead; WtIMvk  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) }N?g|  
{
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nStartPos += fileAccessI.write(b,0,nRead); mge#YV::  
//if(nThreadID == 1) n_v02vFAHT  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); hM?`x(P  
} i8K_vo2Z)  
*oCxof9JA  
_B)s=Snx  
Utility.log("Thread " + nThreadID + " is over!"); >K
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bDownOver = true; o&~dGG4J  
//nPos = fileAccessI.write (b,0,nRead); @B?FE\  
} z. 'Fv7  
catch(Exception e){e.printStackTrace ();} $; ?c?n+  
} w4UD/zO  
} >w9sE8i  
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//打印回应的头信息 iQq
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public void logResponseHead(HttpURLConnection con) tww=~!  
{ $]C=qM28-  
for(int i=1;;i++) wh%xkXa[ur  
{ :vpl+)n  
String header=con.getHeaderFieldKey(i); tZbFvk2  
if(header!=null) 6,X+1EXY  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); C,fY.CeI  
Utility.log(header+" : "+con.getHeaderField(header)); Pb#P`L7OB  
else vm8$:W2 }  
break; !v0"$V5+i  
} /hL\,x2  
} g0PT8]8  
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public void splitterStop() 9TC) w|
 
{ 58::h.:  
bStop = true; ~(P&g7u  
} 09'oz*v{#  
30s; }  
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} {Ur7#h5  
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/* m^<p8KZ  
**FileAccess.java :5J_5,?;`
 
*//文件访问(定位，写) p}uncIod  
package NetFox; pr_>b`p6  
import java.io.*; 28a$NP\KW  
sf$o(^P9\A  
t8P PE  
public class FileAccessI implements Serializable{ _g~2R#2Q  
:|rPT)yT]  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 )n>+m|IqY(  
RandomAccessFile oSavedFile; YlTaN,?j  
long nPos; c;9.KCpwx  
,[* ;U
R  
*$S#o#5  
public FileAccessI() throws IOException ^*0'\/N&  
{ <`)iA-Df;9  
this("",0); L_Q S0_1
 
} {L].T#  
BgM%+b8u  
-}P7$|O&  
public FileAccessI(String sName,long nPos) throws IOException ]W/>Ldv  
{ 3@_Elu  
oSavedFile = new RandomAccessFile(sName,"rw"); zyFUl%  
this.nPos = nPos;
L0L2Ns  
oSavedFile.seek(nPos); M/pMs 6  
} 0mTr-`s  
eklgLU-+fW  
]n;1x1'  
public synchronized int write(byte[] b,int nStart,int nLen) &l m#  
{ )"|||\Iv  
int n = -1; |0g{"}%  
try{ 2}vNSQvG  
oSavedFile.write(b,nStart,nLen); d$G}iJ8$mp  
n = nLen; 1y(UgEg   
} 8PBvV[  
catch(IOException e) Z+4D.bA  
{ T7[NcZ:I  
e.printStackTrace (); yz8jU*H  
} $,ikv?"L  
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6@V~0DG  
return n; v7,$7@$:\  
} XogVpkA  
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} 3TS_-l  
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/* /TV=$gB`  
**SiteInfoBean.java Dvc&RG  
*/ e2cP *J  
package NetFox; 6;iJ*2f5V  
;wHCj$q  
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public class SiteInfoBean { xr%#dVk  
nB5zNyY4  
LT VF8-v  
private String sSiteURL; //Site's URL b~w=v_[(I  
private String sFilePath; //Saved File's Path te,[f  
private String sFileName; //Saved File's Name Y`BRh9Sa  
private int nSplitter; //Count of Splited Downloading File }t%W1UJ  
z~{&}Em ~  
ypdT&5Mqb!  
public SiteInfoBean() m@Rtlb  
{//nSplitter的缺省值为5 y7)(LQRE {  
//default value of nSplitter is 5 yN6>VD{F  
this("","","",5); &JP-O60  
} 5Qh?>n>*  
}`\/f  
eOI (6U!  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) CAD@XZSh  
{ 6"f}O<M5H  
sSiteURL= sURL; OI}cs2m  
sFilePath = sPath; &(N+.T5cp  
sFileName = sName; .@F]Pht  
this.nSplitter = nSpiltter; <RNJ>>0  
T~:|!`  
4\M.6])_  
} EYX$pz(x;  
$O)3q $|  
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public String getSSiteURL() 7msAhz  
{ $F'>yop2b  
return sSiteURL; DA&?e~L&H  
} Np+&t}  
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public void setSSiteURL(String value) JW.=T)  
{ 9f+>ix,ek*  
sSiteURL = value; C3NdE_E  
} \ZU1Jb1c  
umi5Wb<  
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public String getSFilePath() u8GMUN  
{ kOo~%kcQ'  
return sFilePath; %zk$}}ti.  
} Y!J>U  
7R!5,Js+  
??60,
m:]  
public void setSFilePath(String value) ={>Lrig:l  
{ $37 g]ZD  
sFilePath = value; %ru;;h  
} 6GPp>X  
 Q6'x\  
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public String getSFileName() c(;a=n(E#  
{ DwHF[]v'  
return sFileName; ,Uhb  
} >9e(.6&2XZ  
G6@M&u5RT  
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public void setSFileName(String value) I`KQ|h0%  
{ w }^ I  
sFileName = value; ?`zXLY9q7  
} } :=Tm]S  
`K~AhlJUQ  
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public int getNSplitter() B33$
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{ ABE@n%|`  
return nSplitter; :
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} I$N8tn+E  
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public void setNSplitter(int nCount) !l]dR@e  
{ Wjhvxk  
nSplitter = nCount; &nBa
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} J]f3CU,<N  
} e@:sR  
_4^R9Bt  
l2N]a9bq@  
/* iY"l
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**Utility.java \%^%wXfp  
*/ ]BR,M4   
package NetFox; U!U$x74D5  
sBrI}[oyx  
{ZY+L;eg1  
public class Utility { P) 3mX.(}  
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public Utility() E4m`  
{ M%jPH  
Y"A/^]   
UfS%71l.$  
} p+)YTzzc  
#9K-7je;j  
//线程睡眠 ME'|saP  
public static void sleep(int nSecond) _6ay-u  
{ RV@*c4KvO+  
try{ lz1wO5%h  
Thread.sleep(nSecond); "*G.EiLq  
} mZd , 9  
catch(Exception e) 4:gRr   
{ }.s~T#v  
e.printStackTrace (); M|:UwqV>  
} gz3pX#S  
} {nLjY|*  
Qxj JN^Q  
//日志 M(/r%-D  
public static void log(String sMsg) [jmd  
{ !
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System.err.println(sMsg); w*R$o
 
} 8By|@LO  
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VkZ7#  
public static void log(int sMsg) nqLA}u4IM  
{ }iuWAFZbGS  
System.err.println(sMsg); j_Yp>=+[  
} BCA&mi3q  
} fkac_X$7  
o}ZdTf=  
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/* i>(e}<i  
**TestMethod.java wii
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*/ ti#7(^
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package NetFox; 8YbE`32  
AvW:<}a,  
Cg(Y&Gxf.  
public class TestMethod { X7rMeu  
uCcYPvm  
U*)8G  
public TestMethod() -,U3fts  
{ ///xx/weblogic60b2_win.exe aTt12Sc  
try{ '*3h!lW1.  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); kBffF@{  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); j:VbrR  
SiteFileFetch fileFetch = new SiteFileFetch(bean); b9l;a+]d  
fileFetch.start(); *6VF $/rP  
} fZoHf\B]{  
catch(Exception e){e.printStackTrace ();} jbAx;Xt'=M  
OynXkH]0T+  
'ET~  
} :2EDjW  
2 O%`G+\)  
;5)P6S.D  
public static void main(String[] args) ]?(-[  
{ dUhY\v oQ  
new TestMethod(); ajEjZ6  
} @<elq'2  
} Fx2bwut.K  
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