http断点续传简单实现（java)

/* U%E364;F  
**SiteFileFetch.java byetbt(IF  
*/ ftwn<B  
package NetFox; <WRrB `nO  
import java.io.*; 5Cjh%rj(jl  
import java.net.*; >7I"_#x1:  
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y ZR\(\?<  
public class SiteFileFetch extends Thread { ;f+bIYQz  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 2qxede  
long[] nStartPos; //开始位置 {m7>9{`  
long[] nEndPos; //结束位置 "`&1"*  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 9s@$P7N5B  
long nFileLength; //文件长度 .sR=Mf7T  
boolean bFirst = true; //是否第一次取文件 Tkf JC|6  
boolean bStop = false; //停止标志
k@/s-^ry3  
File tmpFile; //文件下载的临时信息 |ww@V<'/#  
DataOutputStream output; //输出到文件的输出流 1a>TJdoa  
Q% LQP!Kg  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） UUaC@Rs2  
public SiteFileFetch(SiteInfoBean bean) throws IOException y=spD^tM8  
{ 1^_V8dm)  
siteInfoBean = bean;
yV/A%y-P  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); # 8fq6z|JZ  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); @Rp#*{  
if(tmpFile.exists ()) Nr#" 5<W  
{ 2E*h,Mo  
bFirst = false; o+I'nFtnI  
read_nPos(); sxFkpf_h  
} IFfB3{J  
else U+wfq%Fz  
{ $F/Uk;*d!  
nStartPos = new long[bean.getNSplitter()]; yTwtGo&  
nEndPos = new long[bean.getNSplitter()]; $Y9Wzv3Ra  
} A-om?$7  
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} !au%D?w  
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public void run() X[r\ Qa  
{ '|^<|S_+K  
//获得文件长度 nht?58  
//分割文件 2~(\d\k  
//实例FileSplitterFetch E[2>je  
//启动FileSplitterFetch线程 5w$\x+no  
//等待子线程返回 0` \!O(jJ  
try{ dAkJ5\=*  
if(bFirst) 052ezh_  
{ 7IUu] Fi  
nFileLength = getFileSize(); Gbrc!3K2  
if(nFileLength == -1) IP=."w  
{ FhVoN}  
System.err.println("File Length is not known!"); lbUUf}   
} nOj0"c  
else if(nFileLength == -2) # )]L3H<  
{ yON";|*\m  
System.err.println("File is not access!"); T>qI,BEY  
} +o[-ED  
else B9i<="=p  
{ ,ctm;T1H+  
for(int i=0;i<nStartPos.length;i++) {RPZq2Tpc  
{ ZxvBo4>tH  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Kdr7JQYzuz  
} Ia!B8$$'RP  
for(int i=0;i<nEndPos.length-1;i++) ywj'S7~A  
{ \mGok<b4  
nEndPos = nStartPos[i+1]; .qAlPe L:  
} I5mtr  
nEndPos[nEndPos.length-1] = nFileLength; %=EN 3>,  
} kK&M>)&o#  
} "-afHXED  
0P7sMCYu  
-jdhdh  
//启动子线程 .Mb<.R3  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 3tu:Vc.:M  
for(int i=0;i<nStartPos.length;i++) V~!lY\  
{ Tw0GG8(c  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), U1;<NUg  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 3Eu;_u_  
nStartPos,nEndPos,i); $l+DkR+  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); +\/1V`  
fileSplitterFetch.start(); Wt 1]9{$  
} |(77ao3  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Iq["(!7E5  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); SL ) ope  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", i4s_:
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nEndPos = " + nFileLength); H2 Gj(Nc-  
// fileSplitterFetch[nPos.length-1].start(); |Ta-D++]'  
2?)8s"Y  
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//等待子线程结束 S<nf"oy_K  
//int count = 0; UZJ<|
[  
//是否结束while循环 +pG[ [}/  
boolean breakWhile = false; v_L2>Pa.  
K2 b\9}  
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while(!bStop) n3B#M}R  
{ CD:$22*]  
write_nPos(); v{c,>]@
 
Utility.sleep(500); 3[;fO_R  
breakWhile = true; ScCA8JgY  
u|{(m_"H  
CEHtr90P  
for(int i=0;i<nStartPos.length;i++) B+r$_L&I  
{ Ehw2o-s^  
if(!fileSplitterFetch.bDownOver) !LAC_b  
{ A-*y[/  
breakWhile = false; 2PTAIm Rq  
break; #_?m.~`g[  
} tQ7:4._  
} )~2~q7  
if(breakWhile) 7GG:1:2+>  
break; >O$JS,  
y)*W!]:7^>  
u0{R;)  
//count++; z`esst\aV  
//if(count>4) rJK
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// siteStop(); 
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} T:=ST3#m  
#ni:Bwtl{  
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System.err.println("文件下载结束！"); ?ytY8`PC  
} a>8&B  
catch(Exception e){e.printStackTrace ();} 6QM$aLLP?  
} dng^#|X)?  
>i!y[F  
v9
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//获得文件长度 k(ho?  
public long getFileSize() ?R":"*eu  
{ )\RG NJMC  
int nFileLength = -1; M'|?*aNK  
try{ !=bGU=^  
URL url = new URL(siteInfoBean.getSSiteURL()); ;}KT 3Q<^  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); [MXyOE  
httpConnection.setRequestProperty("User-Agent","NetFox"); 5hj _YqQ7  
;FnU[Q`M#L  
C/#?S=w`4  
int responseCode=httpConnection.getResponseCode(); ;6}> Shs  
if(responseCode>=400) 1uco{JX<S  
{ *)D$w_06S  
processErrorCode(responseCode); 2|\WaH9P  
return -2; //-2 represent access is error O<()T6  
} \&\U&^?  
D5"Xjo*  
MN^d28^/  
String sHeader; m(KBg'kQ  
w\lc;4U   

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for(int i=1;;i++) l8H8c &  
{ +%=lu14G  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); MREB  
//Utility.log(in.readLine()); >UnLq:
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sHeader=httpConnection.getHeaderFieldKey(i); ]O&\Pn0q  
if(sHeader!=null) 3Pgld*i7  
{ ^y.|KA3[  
if(sHeader.equals("Content-Length")) !S#K6:  
{ L};P*{q2Z  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); J b?x-%Za  
break; o3cE.YUF  
} PS$g*x  
} 0iI|eE o  
else M3!4,_!~  
break; 'l $ViNq;  
} '37 <+N  
} 'OI(MuSn  
catch(IOException e){e.printStackTrace ();} UK5u"@T  
catch(Exception e){e.printStackTrace ();} aNUMF  
p}p}!M|  
}6"l`$=Ev  
Utility.log(nFileLength); FBeo@  
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_%KRZx}  
return nFileLength; rEwd76?  
} ZxAk  
_[h!r;DsG  
t~%(Zu>S  
//保存下载信息（文件指针位置） q}gM2Ia'vY  
private void write_nPos() L~("C  
{ M'nzoRk  
try{ %$'Z"njO&  
output = new DataOutputStream(new FileOutputStream(tmpFile)); E<'V6T9bi  
output.writeInt(nStartPos.length); 5}TTf2&Xo#  
for(int i=0;i<nStartPos.length;i++) "Pl.G[Buc-  
{ U;#G$  
// output.writeLong(nPos); ($Q|9>5,  
output.writeLong(fileSplitterFetch.nStartPos); %?Q<  
output.writeLong(fileSplitterFetch.nEndPos); 1EWskmp  
} #xh M&X  
output.close(); cb }OjM F  
} j[4l'8Ek  
catch(IOException e){e.printStackTrace ();} Uc9hv?  
catch(Exception e){e.printStackTrace ();} E&dxM{`  
} rN'8,CV  
M>ntldV#g%  

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//读取保存的下载信息（文件指针位置） 7U:{=+oLR  
private void read_nPos() v >cPr(  
{ L),r\#Y(v  
try{ {__NVv  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); }b^x#HC  
int nCount = input.readInt(); vG:S(/\>  
nStartPos = new long[nCount]; V;"Rp-`^  
nEndPos = new long[nCount]; !b?
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for(int i=0;i<nStartPos.length;i++) K!(hj '0.  
{ 9^E!2CJ  
nStartPos = input.readLong(); ^qLesP#   
nEndPos = input.readLong(); "~q~)T1Z  
} iL|5}x5\  
input.close(); ujf7r`;u.  
} M'JCT'(X  
catch(IOException e){e.printStackTrace ();} N!./u(b  
catch(Exception e){e.printStackTrace ();} hjz`0AS  
} p\Fxt1Y@X  
3Xm> 3  
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private void processErrorCode(int nErrorCode) ;Irn{O  
{ @M6F?;  
System.err.println("Error Code : " + nErrorCode); :qj7i(
  
} p@U[fv8u  
]U&<y8Q_6  
~Rw][Ys  
//停止文件下载 k\Y*tY#2  
public void siteStop() "sT)<Wc  
{  v>s,*  
bStop = true; 4'"WD0  
for(int i=0;i<nStartPos.length;i++) =R)w=ce  
fileSplitterFetch.splitterStop(); 8?ip,Q\  
9\uBX.]x  
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} u/ri {neP{  
} 6!H,(Z]j  
//负责部分文件的抓取 ?kS#g  
**FileSplitterFetch.java `A<2wd;  
*/ T(Ji%S>  
package NetFox; x,HD,VQR/  
55/)2B2J  
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import java.io.*; )hC3'B/[Y  
import java.net.*; e/x6{~ju^N  
T.W^L'L`  
v8zOY#?  
public class FileSplitterFetch extends Thread { ^%0^DN  
VO~%O.>  
q2/kegAT  
String sURL; //File URL }*S`1IWMj  
long nStartPos; //File Snippet Start Position c]"w0a-`^@  
long nEndPos; //File Snippet End Position \Nk578+AA  
int nThreadID; //Thread's ID Jp= )L  
boolean bDownOver = false; //Downing is over ,y@WFRsx  
boolean bStop = false; //Stop identical 
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FileAccessI fileAccessI = null; //File Access interface mY]o_\`  
cPkP/3I]h  
LI<Emez  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException G8'  
{ 5s@xpWVot  
this.sURL = sURL; sRZ?Ilua6  
this.nStartPos = nStart;  FL b  
this.nEndPos = nEnd; *S?'[PS]1  
nThreadID = id; u8gqWsvruM  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 O:ACp<@  
} "{kE#`c6<n  
"{Hl! Zq/  
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public void run() KGc
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{ cj[x%eK>  
while(nStartPos < nEndPos && !bStop) smn~p/u  
{ MI-S}Qoe  
6n
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WVz2 bzj  
try{ Tp.:2[  
URL url = new URL(sURL); _# cM vlk  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); KD]`pqN9  
httpConnection.setRequestProperty("User-Agent","NetFox"); U;0:@.q  
String sProperty = "bytes="+nStartPos+"-"; db@^CS[P  
httpConnection.setRequestProperty("RANGE",sProperty); 0O>M/ *W  
Utility.log(sProperty); :4)(
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n5)ml)m  
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InputStream input = httpConnection.getInputStream(); cP\ZeG#<  
//logResponseHead(httpConnection); !tb!%8{~  
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byte[] b = new byte[1024]; Y!+H9R  
int nRead; ;j qF:Wl@  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) H[}lzL)  
{ ?zfm"o  
nStartPos += fileAccessI.write(b,0,nRead); 0/1=2E^,  
//if(nThreadID == 1) d c/^  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); RJKi98xwJ  
} rITA-W O  
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Utility.log("Thread " + nThreadID + " is over!"); 6:AEg  
bDownOver = true; a8-V`  
//nPos = fileAccessI.write (b,0,nRead);  Frz  
} cc
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catch(Exception e){e.printStackTrace ();} lnK  
} 7{7Y[F0  
} 9EY`j,{4  
rz&'wCiOO  
;-BN~1Jg  
//打印回应的头信息 UZ "!lpg  
public void logResponseHead(HttpURLConnection con) sbhzER  
{ [rW];H8:~  
for(int i=1;;i++) T8%!l40v  
{ EhW"s%Q  
String header=con.getHeaderFieldKey(i); Lf%=vd  
if(header!=null) d
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//responseHeaders.put(header,httpConnection.getHeaderField(header)); Zz+v3
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Utility.log(header+" : "+con.getHeaderField(header)); [lVfhXc&  
else TY5R=jh=  
break; <P
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} Uq`6VpZ  
} _+Sf+ta  
o^Lq8u;i*  
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public void splitterStop() Lb
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{ [9V}>kS)  
bStop = true; 6b$C/  
} `)4v Q+A>  
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} a)c;z@r  
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/* Zu~w:uNmU  
**FileAccess.java u&[L!w  
*//文件访问(定位，写) -7'|&zP  
package NetFox; bfm+!9=9S  
import java.io.*; 0pG +yec  
N%ccy?B  
z]-m<#1  
public class FileAccessI implements Serializable{ &328pOT4  

"6U@e0ht  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 <QC7HR  
RandomAccessFile oSavedFile; uPapINj  
long nPos; QgQclML1|  
uqU&k@  
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public FileAccessI() throws IOException t_*x.{x-  
{ {QaO\{J=  
this("",0); 4; 0#Z^p  
} !]E]Xd<  
4]$OO'  
K=E+QvSG  
public FileAccessI(String sName,long nPos) throws IOException gat;Er  
{ VH<d[Mj  
oSavedFile = new RandomAccessFile(sName,"rw"); WPAUY<6f  
this.nPos = nPos; ;\6@s3  
oSavedFile.seek(nPos); kPiY|EH  
} mEu2@3^E }  
N
~fE&@-  
ULBEe@s  
public synchronized int write(byte[] b,int nStart,int nLen) jT< I`K*  
{ ?1c7wEk  
int n = -1;  ;(J&%  
try{ x DNu'  
oSavedFile.write(b,nStart,nLen); j@^zK!mO  
n = nLen; c q[nqjC=  
} -Eig#]Se3  
catch(IOException e) zi_$roq=)  
{ ARt{ 2|  
e.printStackTrace (); !8T04988j  
} B|yz~wuS  
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return n; w{|`F>f9  
} *s-s1v  
UN
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} U<Qi`uoj!  
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/* tm1&OY  
**SiteInfoBean.java u\= 05N6G  
*/ Otx>S' 5  
package NetFox; n4M Xa()P1  
3e47UquZ  
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public class SiteInfoBean { Ha/Qz'^S;  
=Ul"{T<  
i2rSP$j  
private String sSiteURL; //Site's URL [Gv8Fn/aG  
private String sFilePath; //Saved File's Path !g6=/9  
private String sFileName; //Saved File's Name mMOgx   
private int nSplitter; //Count of Splited Downloading File XP0;Q;WF}  
R@s|bs?  
i+in?!@G:  
public SiteInfoBean() !Q_Wbu\U  
{//nSplitter的缺省值为5 G`jvy@  
//default value of nSplitter is 5 b_6c
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this("","","",5); K]Vp! G  
} )=X g  
MffCk!]  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ='w 2"4  
{ 2Xk;]-T!  
sSiteURL= sURL; iAk.pH]a  
sFilePath = sPath; B(vCi^  
sFileName = sName; Z<^EZX3N  
this.nSplitter = nSpiltter; [7~AWZU3  
J$5G8<d>  
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} MBw;+'93qf  
vu.?@k@  
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public String getSSiteURL() VF";
p^  
{ L(cKyg[R  
return sSiteURL; RSbq<f>BFo  
} oF]]Pl{W  
I= <eCv  
koS?UYF`  
public void setSSiteURL(String value) )u28:+8  
{ &4}=@'G@  
sSiteURL = value; ot2zY dWAz  
} 6__
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*QWOWg4w  
:[(%4se  
public String getSFilePath() v0! 1W  
{ \}W3\To_  
return sFilePath; T?d}IDv1  
} #_aq@)Fd  
%+,*$wk#*  
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public void setSFilePath(String value) 7NWkN7:B  
{ _F`JFMS  
sFilePath = value; [kqtkgK$j2  
} c/^jD5U7  
Z|N$qm}  
m%[/w wL  
public String getSFileName() AkW>*x  
{ x3`JC&hF,q  
return sFileName; WjK[% ;Z!  
} ok:L]8UN3  
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EirZ}fDJzB  
public void setSFileName(String value) #}@8(>T  
{ 8q{|nH  
sFileName = value; tu$rVwgM  
} DUl+Jqn4B  
"+7E9m6I  
1:^Xd~X  
public int getNSplitter()
r,Xyb`  
{ XMkRYI1~  
return nSplitter; }0]u
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} [)jNy_4  
SJh~4R\  
|te=DCO  
public void setNSplitter(int nCount) _6,\;"it?8  
{ w|S b`eR  
nSplitter = nCount; 3<M yb  
} (7b9irL&cn  
} {'h&[f>zcQ  
v&/H6r#E.  
:7"Q  
/* +y'2 h%>h[  
**Utility.java cAwqIihZ  
*/ nh@JGy*L  
package NetFox; 0x5Ax=ut  
j\bp#+  
$H)!h^7^9  
public class Utility { G,$nq4  
b-#{O=B  
N*$GP3]  
public Utility() .uS`RS8JM  
{ uI?Z_  
sU*?H`U3d  

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} 4TPdq&';C:  
Op]*wwI*h  
//线程睡眠 n~\; +U  
public static void sleep(int nSecond) 5XHejHn>  
{ =j- ,yxBvJ  
try{ u<fZ.1  
Thread.sleep(nSecond); >K,QP<B  
} ^W:a7cMw  
catch(Exception e) : Bo
  
{ xxl|j$m  
e.printStackTrace (); e/:?9  
} hI*v)c  
} )~R[aXkvY  
Cx/J_Ro#  
//日志 R?:Q=7K  
public static void log(String sMsg) ~D|,$E tX4  
{ (2>q  
System.err.println(sMsg);
vWESu4W`L  
} ~!PWJ~U  
L YB@L06a  
'V:MppQVZ.  
public static void log(int sMsg) B?-w<":!  
{ KU(BY}/ ^  
System.err.println(sMsg); 2 G*uv+=  
} aAGV\o{^  
} e<9 ^h)G  
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}cCIYt\RK  
/* &Lt$~}*&6  
**TestMethod.java #'>)?]tn  
*/ Bx5xtJ|!  
package NetFox; #9[>  
+3-5\t`  
X,3\c:  
public class TestMethod { FA{Q6fi:2  
:X'
B K4EN  
[[<TW}  
public TestMethod() ]*k ~jY,  
{ ///xx/weblogic60b2_win.exe 
.4"BN<9  
try{ j][&o-Ev  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); \yw5`5g  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); >I~Q[  
SiteFileFetch fileFetch = new SiteFileFetch(bean); =Jw*T[E  
fileFetch.start(); Fs4shrt  
} P,)D0i  
catch(Exception e){e.printStackTrace ();} ey[Z<i1  
>M{98NH  
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} `Rt w'Uz  
9%NsW3|  
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public static void main(String[] args) /LWk>[
Z;  
{ S{&%tj~U  
new TestMethod(); ~<K,P   
} jG{?>^
 
} xsRkO9x  
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