http断点续传简单实现（java)

/* u59l)8=  
**SiteFileFetch.java !pRu?5  
*/ ?[bE/Ya+S  
package NetFox; 2V%z=  
import java.io.*; &d6ud|  
import java.net.*; yU/?4/G!  
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t\QLj&h}E  
public class SiteFileFetch extends Thread { $X-PjQb1Bb  
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SiteInfoBean siteInfoBean = null; //文件信息Bean \reVA$M[  
long[] nStartPos; //开始位置 XRkUv>Yk  
long[] nEndPos; //结束位置 IEm~^D#<=  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 "XV@OjrE  
long nFileLength; //文件长度 EpR
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boolean bFirst = true; //是否第一次取文件 aqk$4IG  
boolean bStop = false; //停止标志 aqqo>O3 s  
File tmpFile; //文件下载的临时信息 %X\A|V&  
DataOutputStream output; //输出到文件的输出流 R0#scr  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） k kD#Bb  
public SiteFileFetch(SiteInfoBean bean) throws IOException C[%&;\3S@  
{ Sn'!Nq>  
siteInfoBean = bean; 6y Muj<L  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); '3^q
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tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); RAhDSDf  
if(tmpFile.exists ()) V D7^wd9  
{ 4?@#w>(  
bFirst = false; |[5;dt_U/  
read_nPos(); A9SL|9Q  
} n2-+.9cY  
else ami>Pp  
{ 3SbZD  
nStartPos = new long[bean.getNSplitter()]; 2+)h!y]  
nEndPos = new long[bean.getNSplitter()]; t>%b[(a  
} IFr"IOr'l  
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} =,ax"C?pR  
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public void run() t1 9f%d  
{ e~)4v  
//获得文件长度 D5Sbs(  
//分割文件 _8K8Ai-~.>  
//实例FileSplitterFetch JBw2#ry  
//启动FileSplitterFetch线程 uA =%EEZ  
//等待子线程返回 Bx}"X?%S  
try{ _nzq(m1@  
if(bFirst) ,MJddbcg  
{ [c
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nFileLength = getFileSize(); 9'~qA(=.?  
if(nFileLength == -1) 8/)q$zs  
{ !F~1+V>zP  
System.err.println("File Length is not known!"); bxxLAWQ(  
} \6APU7S  
else if(nFileLength == -2) WhH60/`  
{ 5"3`ss<m  
System.err.println("File is not access!"); I+kL;YdS  
} 3l`"(5  
else N#-.[9!  
{ =bJ$>Djp  
for(int i=0;i<nStartPos.length;i++) }D)eS |B  
{ v+sF0 j\P  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); n{<@-6  
} AIQ {^:  
for(int i=0;i<nEndPos.length-1;i++) {U3jJ#K  
{ {df;R|8l  
nEndPos = nStartPos[i+1]; xo @|;Z>&F  
} /{8Y,pZbu  
nEndPos[nEndPos.length-1] = nFileLength; @##}zku  
} H*0g*(  
} +RpCh!KP  
zCA8}](C^  
3K~^H1l  
//启动子线程 "N&ix*($  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; cC$YD]XdIA  
for(int i=0;i<nStartPos.length;i++) 8R\6hYJ%F  
{ [D+PDR  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), GadY#]}(  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), V#b*:E.cA  
nStartPos,nEndPos,i); <x;g9Z>(  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); jM6$R1HX  
fileSplitterFetch.start(); F+R1}5-3cl  
} B&59c*K  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Z \ @9*  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); zSsBbu:  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", s/~[/2[bnf  
nEndPos = " + nFileLength); ? B|i  
// fileSplitterFetch[nPos.length-1].start(); im:[ViR {  
9%ct   
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//等待子线程结束 q2*)e/}H  
//int count = 0; ]!P6Z?  
//是否结束while循环 Qz{Vl>"  
boolean breakWhile = false; BSSe
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q |Pebe=  
while(!bStop) u}R|q  
{ dXY}B=C  
write_nPos(); 13 JG[,w  
Utility.sleep(500); ;2fzA<RkK  
breakWhile = true; K]>4*)A:  
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for(int i=0;i<nStartPos.length;i++) "k [$euV  
{ Wx;%W"a  
if(!fileSplitterFetch.bDownOver) UDcr5u eKn  
{ IWN18
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breakWhile = false; S$wC{7?f  
break; 'i3-mZ/|8  
} ]NWcd~"b!Z  
} KU+u.J  
if(breakWhile) l&] %APL  
break; MB>4Y]rtU  
+ZE"pA^C  
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//count++; u5U^}<}y}  
//if(count>4) d@Bd*iI<  
// siteStop(); F)'_,.?0  
} Bgsi$2hI  
!VG ]~lc  
=.m/X>  
System.err.println("文件下载结束！"); srImk6YD  
} #z_.!E  
catch(Exception e){e.printStackTrace ();} (l2n%LL]*  
} \:n<&<aVSr  
ZS_ z  
/!"sPtIh  
//获得文件长度 yQu/({D  
public long getFileSize() 98zJ?NaD&  
{ ~U8#yo  
int nFileLength = -1; 9K&YHg:1  
try{ )r*F.m{&:  
URL url = new URL(siteInfoBean.getSSiteURL()); 1Nv qtVC  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); <Fl.W}?Q}  
httpConnection.setRequestProperty("User-Agent","NetFox"); B~<bc  
y?}<SnjP:  
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7?  
int responseCode=httpConnection.getResponseCode(); g
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if(responseCode>=400) 5X]f}6kT  
{ XL1
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processErrorCode(responseCode); |w_l~xYV)  
return -2; //-2 represent access is error ct(euPU  
} 6@(o8i   
R>[G6LOG  
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String sHeader; 5HAAaI  
/b4>0DXT5  
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for(int i=1;;i++) {t'SA]|g  
{ \4OU+$m  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); h2+"e# _  
//Utility.log(in.readLine()); eVbT<9k  
sHeader=httpConnection.getHeaderFieldKey(i); e5n"(s"G*[  
if(sHeader!=null) +rr
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{ {FN4BC`3+  
if(sHeader.equals("Content-Length")) [NGq$5  
{ 4*q6#=G  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); NPE 4@c_a@  
break; \)g}  
} RM25]hx  
} =G 'c%  
else ;Q5o38(  
break; 6k|f]
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} _*t75e$-  
} H5gcP11r  
catch(IOException e){e.printStackTrace ();} `[_p,,}Ir  
catch(Exception e){e.printStackTrace ();} `Z2-<:]6&a  
,;h}<("q  
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Utility.log(nFileLength); WZbRR.TxO  
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return nFileLength; [F27i#'I]  
} 4 `}6W>*R  
RS{E|  
3XUie;*`  
//保存下载信息（文件指针位置） Z+FhI^  
private void write_nPos() Fdx4jc13w  
{ ]e?L,1-  
try{ ?Bd6<F-G  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 9.Sv"=5gz  
output.writeInt(nStartPos.length); d8^S~7  
for(int i=0;i<nStartPos.length;i++) fhki!# E8M  
{ 91FVe  
// output.writeLong(nPos); Nqj5,9*c  
output.writeLong(fileSplitterFetch.nStartPos); [Z]C
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output.writeLong(fileSplitterFetch.nEndPos); #\LYo{op/.  
} KM oDcAjH  
output.close(); zK:2.4  
} 6ZC~q=my  
catch(IOException e){e.printStackTrace ();} ]vCs9*
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catch(Exception e){e.printStackTrace ();} GkdxwuRw  
} :-+j,G9t  
.7Itbp6=R  
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//读取保存的下载信息（文件指针位置） 6s:  
private void read_nPos() '"V]>)  
{ o~'UWU'#
 
try{ ~2XiKY;W?  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); h7}P5z0F  
int nCount = input.readInt(); X/S%0AwZ  
nStartPos = new long[nCount]; mGUG  
nEndPos = new long[nCount]; cN:ek|r  
for(int i=0;i<nStartPos.length;i++) ^QTkre  
{ zgSv -h+f  
nStartPos = input.readLong(); `S]DHxS  
nEndPos = input.readLong(); B!1L W4^  
} "
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input.close(); DPlmrN9@=  
} _&$nJu  
catch(IOException e){e.printStackTrace ();} +Jq~39  
catch(Exception e){e.printStackTrace ();} #4^D'r>pJ  
} ~H626vT37  
)dRBI)P  
<TEDs4 C  
private void processErrorCode(int nErrorCode) 8H{9  
{ 8-Z|$F"  
System.err.println("Error Code : " + nErrorCode); >td\PW~X  
} )KN]"<jB  
h]
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=#?=Lh  
//停止文件下载 E@)9'?q  
public void siteStop() ]7%+SH,RdD  
{ $4>x4*  
bStop = true; EvDg{M}  
for(int i=0;i<nStartPos.length;i++) dYp} R>+  
fileSplitterFetch.splitterStop(); 6p~8(-nG  

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TI637yqCU  
} V_H0z  
} "l-b(8n  
//负责部分文件的抓取 T:w%RF[v9  
**FileSplitterFetch.java 5GWC  
*/ DcNwtts  
package NetFox; +2^Mz&I@b  
vb]H$@0  
;-{'d8  
import java.io.*; P{>-MT2E  
import java.net.*; !u%XvxJwDb  
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public class FileSplitterFetch extends Thread { 4]ETF+   
q<Wz9lDMNR  
2!6
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String sURL; //File URL Q|W~6  
long nStartPos; //File Snippet Start Position RjG=RfB'V  
long nEndPos; //File Snippet End Position /8s>JPXKH[  
int nThreadID; //Thread's ID KA]5tVQA  
boolean bDownOver = false; //Downing is over :stA]JB# w  
boolean bStop = false; //Stop identical Vg1MA  
FileAccessI fileAccessI = null; //File Access interface d)v'K5  
:.F;LF&  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException SQI =D8  
{ {'q(a4  
this.sURL = sURL; -ob1_0  
this.nStartPos = nStart; hkvymHaG  
this.nEndPos = nEnd; Vg8c}
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nThreadID = id; E>x,$w<?  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 &v&e-|r8;  
} P&9&/0r=_  
k(3FT%p  
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public void run() ;cW9NS3:  
{ q-d#bKIf  
while(nStartPos < nEndPos && !bStop) {s~t>Rp+  
{ E9PD1ADR  
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try{ -jL10~/  
URL url = new URL(sURL); PRyzUG&  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); {{e+t8J??  
httpConnection.setRequestProperty("User-Agent","NetFox"); \PgMMc4'  
String sProperty = "bytes="+nStartPos+"-"; eih~ SBSH  
httpConnection.setRequestProperty("RANGE",sProperty); d<afO?"  
Utility.log(sProperty); &s_)|K  
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InputStream input = httpConnection.getInputStream(); +p_>fO  
//logResponseHead(httpConnection); mpDQhD[n  
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byte[] b = new byte[1024]; [5s4Jp$+  
int nRead; C!S(!Z,  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Tyt1a>!qA  
{ _
6{XqvWqb  
nStartPos += fileAccessI.write(b,0,nRead); {x/)S*:Z  
//if(nThreadID == 1) =9cN{&qf  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); . I#d
R*  
} !6DH6<HC  
!ZTBiC5R  
3q:>NB<  
Utility.log("Thread " + nThreadID + " is over!"); Bq#B+JwX  
bDownOver = true; >r5s>A[YC  
//nPos = fileAccessI.write (b,0,nRead);  B/ACU  
} QAKA3{-(  
catch(Exception e){e.printStackTrace ();} Xmaj7*f>p  
} \tZZn~ex  
} E|hW{oX3  
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gC\^"m  
//打印回应的头信息 h(3ko An  
public void logResponseHead(HttpURLConnection con) D;WQNlTU  
{ \ q=Bbfzv  
for(int i=1;;i++) G7d)X^q!xS  
{ KPMId`kf  
String header=con.getHeaderFieldKey(i); cuo'V*nWQ  
if(header!=null) ":,J<|Oy  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ok<!/"RX$  
Utility.log(header+" : "+con.getHeaderField(header)); a;[=bp  
else a<mM )[U  
break; \XT~5N6  
} )MU)'1jc,  
} o<nkK+=Afm  
>.f'_2#Z&  
8:)itYE  
public void splitterStop() eJtfQ@?  
{ !w=6>B^  
bStop = true; y9)Rl)7-:  
} ':LV"c4t  
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} Q=Y1kcTOn  
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/* ?wYvBFRn7"  
**FileAccess.java K1*]6x,  
*//文件访问(定位，写) 3lD1G~  
package NetFox; |\_d^U&`  
import java.io.*; fPu,@ L  
Y<EdFzle  
(n3MbVi3LU  
public class FileAccessI implements Serializable{
RYem(%jq  
Z/w "zCd  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 <m!(eLm+B  
RandomAccessFile oSavedFile; 47 *,  
long nPos; [Uw/;Kyh  
hj|P*yKV  
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public FileAccessI() throws IOException RbGq$vYol/  
{ &['cZ/bM
 
this("",0); @Ap~Wok  
} [
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vgvJ6$#  
public FileAccessI(String sName,long nPos) throws IOException rLzN#Zoi  
{ xD3Y-d9  
oSavedFile = new RandomAccessFile(sName,"rw"); '2BE"e  
this.nPos = nPos; ( 17=|s  
oSavedFile.seek(nPos); {#X]D~;s+  
} .|Zt&5osI  
A,'JmF$d  
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public synchronized int write(byte[] b,int nStart,int nLen) ~99DE78  
{ xU_Dg56z'&  
int n = -1; 3iC$ "9!p  
try{ $X%'j
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oSavedFile.write(b,nStart,nLen); i`)h~V
|G  
n = nLen; ~i ImM|*0  
} g8^YDrH  
catch(IOException e) ,Kw]V %xOb  
{ xesZ7{ o  
e.printStackTrace (); 4OOH 3O  
} ,]UCq?YW)T  
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return n; x."/+/  
} bO2s'!x  
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} G^Q8B^Lg  
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/* ':jsCeSB  
**SiteInfoBean.java @CJ`T&  
*/ edv&!  
package NetFox; V`/D!8>  
FhkS"y  
2y0J~P!I  
public class SiteInfoBean { ,m)k;co^  
!QTfQ69Y0  
;@R=CQ6  
private String sSiteURL; //Site's URL 2GRdfX  
private String sFilePath; //Saved File's Path qB0F9[U  
private String sFileName; //Saved File's Name B<p -.tv  
private int nSplitter; //Count of Splited Downloading File fi.[a8w:W  
/\0rRT  
$V0G[!4  
public SiteInfoBean() Bl"BmUn  
{//nSplitter的缺省值为5 =KctAR;  
//default value of nSplitter is 5 5RysN=czA  
this("","","",5);
<@puWm[p  
} >m-VBo  
{hmC=j  
(ndTEnpp  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) MY]<^/Q  
{ 6?C|pO  
sSiteURL= sURL; ?mCino  
sFilePath = sPath; X?8EPCk  
sFileName = sName; qij<XNZU"&  
this.nSplitter = nSpiltter; I\DH  
XFiP8aX<  
&=-ZNWNo  
} qlJzXq{|`  
(WISf}[l;  
*49lM;  
public String getSSiteURL() bkvm-$/  
{ ^-&BGQM  
return sSiteURL; (&)PlIi7  
} 8wXnc%  
WX9ABh&5  
-xXz}2S4  
public void setSSiteURL(String value) :47bf<w|Y  
{ &# ?2zbZ  
sSiteURL = value; v,VCbmc  
} $xK2M  
2`?58&  
ip`oL_c  
public String getSFilePath() 7`c\~_Df_  
{ aA|<W g  
return sFilePath; XJ3p<  
} Ww[Xqmg  
P,}cH;w6Ck  
fUg<+|v*  
public void setSFilePath(String value) 5>e
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{ N-9Vx#i  
sFilePath = value; Sl!#!FGI  
} /YLHg5n8+  
R|&Rq(ow"  
'[z529HN  
public String getSFileName() Q/[g
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{ R'udC}  
return sFileName; ?m(]@6qa  
} s6k@WT?"^  
fK %${   
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public void setSFileName(String value) u3B[1Ae:K  
{ YXi'^GU@  
sFileName = value; UBm L:Qv  
} +'ZJ]  
!'jZ !NFO  
XjRk1~  
public int getNSplitter() Biva{'[m  
{ RI[=N:C^  
return nSplitter; #aeKK7[  
} 3!H&bOF  
JdK'~-L  
_-M27^\vV  
public void setNSplitter(int nCount) S#^2k!(|G  
{ Bo#,)%80  
nSplitter = nCount; @BfJb[A#  
} :< d.  
} I0qSx{K  
RnaxRnXVR  
J2BCaAwEP,  
/* XsXO S8  
**Utility.java <?>1eU%  
*/ nc2=S^Fqu  
package NetFox; 9*&c2jh  
/TndB7l"3  
[XKudw%  
public class Utility { aob+_9o  
xk:=.Qqh  
'e(]woe  
public Utility() T)Zef  
{ ' a>YcOw  
)-s9CWJv  
'xP&u<(F  
} $1E'0M`  
<3)k M&.B  
//线程睡眠 sP'U9l  
public static void sleep(int nSecond) Sk6B>O<:  
{ zJ $&`=  
try{ X3dXRDB'  
Thread.sleep(nSecond); 9zL(PkC%\  
} E xls_oSp  
catch(Exception e) }mYxI^n  
{ 7K 'uNPC  
e.printStackTrace (); ;(3!#4`q(]  
} )z^NJ'v4(  
} lZr}F.7  
w!eY)
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//日志 {M^BY,%*  
public static void log(String sMsg) [KMNMg  
{ w:VD[\h  
System.err.println(sMsg); +L,V_z  
} tgVMgu  
.}c&"L;W  
&Yklf?EZ>Q  
public static void log(int sMsg) i<b-$9  
{ Mgp+#w+,  
System.err.println(sMsg); T\wfYuc&X  
} KbSE
=
3  
} +Zg@X.z  
cF
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*8I"7'xh  
/* 'n
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**TestMethod.java <0!O'" "J  
*/ PrKH{nyJk  
package NetFox; =o5|W'>`  
`PUGg[Zx^  
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public class TestMethod { W>j@E|m$  
]<*-pRN  

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public TestMethod() @g5qcj
D'[  
{ ///xx/weblogic60b2_win.exe 4Jf9N'  
try{ r,HIoeAKP  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); q"e]\Tb=we  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 0NF=7 j  
SiteFileFetch fileFetch = new SiteFileFetch(bean); VTwDa*]AhB  
fileFetch.start(); 6dncUfB  
} oMNSQMlI  
catch(Exception e){e.printStackTrace ();} T'> MXFLh  
&\y`9QpVF  
AGGT] 58|  
} !+u K@z&G  
agk
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+^DDWVp  
public static void main(String[] args) QnA~,z/.w  
{ }n(
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new TestMethod(); ;
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} ntntB{t  
} , .E>  
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