http断点续传简单实现（java)

/* 1QF*e'  
**SiteFileFetch.java s@)"IdSA(  
*/ w]Ko/;;^2  
package NetFox; 90h1e7Zc
C  
import java.io.*; :_QAjU  
import java.net.*; ^Im%D(MY  
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public class SiteFileFetch extends Thread { 8K JQ(  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ci_v7Jnwo  
long[] nStartPos; //开始位置 Bpm5dT;  
long[] nEndPos; //结束位置 51ajE2+X&  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 U_}A{bFG  
long nFileLength; //文件长度 sAD P~xvU  
boolean bFirst = true; //是否第一次取文件 Y9@dZw%2  
boolean bStop = false; //停止标志 Ij6Wz.*  
File tmpFile; //文件下载的临时信息 _]D#)-uv}C  
DataOutputStream output; //输出到文件的输出流 ;4/dk_~p]  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） F@K*T2uh  
public SiteFileFetch(SiteInfoBean bean) throws IOException q~Q)'*m  
{ d7_g u  
siteInfoBean = bean; 0n<(*bfW  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); iy.%kHC  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); @ Zgl>
  
if(tmpFile.exists ()) 3gI[]4lRH  
{ Z?~d']XD  
bFirst = false; e
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read_nPos(); ^`jZKh8)h  
} ;&W;  
else lR@i`)'?U  
{ Hr<C2p^a  
nStartPos = new long[bean.getNSplitter()]; -wfRR>)d  
nEndPos = new long[bean.getNSplitter()]; io9xI3{  
} # +QWi0B  
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} Rgfc29(8  
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public void run() y3KcM#[  
{ ra9cD"/J &  
//获得文件长度 s=nVoc{Yt  
//分割文件 ,h@R' f!  
//实例FileSplitterFetch mP)3cc5T  
//启动FileSplitterFetch线程 {KU.  
//等待子线程返回 znQ'm^h  
try{ `j}_BW_  
if(bFirst) _Vo)<--+I  
{ 'Wf?elB+  
nFileLength = getFileSize(); @Ge>i5q  
if(nFileLength == -1) oxMUW<gYd  
{ kh<pLI>$h  
System.err.println("File Length is not known!"); $/, BJ/9  
} Y[iDX#  
else if(nFileLength == -2) WG8iTVwx  
{ y7M:b Uh  
System.err.println("File is not access!"); ?y>Y$-v/C  
} @3-,=x  
else a)_rka1(  
{ l- 1]w$ y  
for(int i=0;i<nStartPos.length;i++) SY$J+YBLM  
{ r)
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); >&<<8Ln  
} p|\%:#  
for(int i=0;i<nEndPos.length-1;i++) j!lAxlOX  
{ y^mWG1"O  
nEndPos = nStartPos[i+1]; b(}Gm@#  
} N;Z`%&  
nEndPos[nEndPos.length-1] = nFileLength; *?^Z)C>  
} Sg.+`xww3  
} e$Xq  
C5PmLiOHY>  
S]e j=6SP  
//启动子线程 d)04;[=  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; fjIcB+Z  
for(int i=0;i<nStartPos.length;i++) _e?q4>B)c  
{ 4?>18%7&  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), I!$jYY2  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Ic[}V0dk  
nStartPos,nEndPos,i); i<4>\nc  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); pKt-R07*  
fileSplitterFetch.start(); )YzHk ;(  
} XMN?;Hj>  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 6o=qJ`m[?  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1);  JJ/1daj  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ,&.W6sW  
nEndPos = " + nFileLength); Z0[)u_<  
// fileSplitterFetch[nPos.length-1].start(); )%iRZ\`f  
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JkSdLj  
//等待子线程结束 yaH Trh%  
//int count = 0; -ajM5S=d*  
//是否结束while循环 IPl@ DH  
boolean breakWhile = false; dSOlD/c  
6X@mPj[/  
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while(!bStop) 4meidKw]  
{ u(p
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write_nPos(); \C]i|]tl  
Utility.sleep(500); H+4=|mkQ  
breakWhile = true; {8^Gs^c c  
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for(int i=0;i<nStartPos.length;i++) xT9Yes&  
{ H-eEhI(;O  
if(!fileSplitterFetch.bDownOver) ?mH@`c,fM  
{ ],;D2]<s  
breakWhile = false; p+, 1Fi  
break; `%-4>jI9-  
} X^zYQ6t  
} hc-lzYS  
if(breakWhile) /635B*g  
break; 33Ssylno
 
`IEq@Wr#$!  
v"z(JF  
//count++; IFiTTIlT0  
//if(count>4) "'['(e+7  
// siteStop(); =2^Vgc  
} u5Qp/ag?N  
`S"W8_m  
#v.L$7O  
System.err.println("文件下载结束！"); \'n$&PFe  
} X'cf&>h  
catch(Exception e){e.printStackTrace ();} u-m%=2  
} Q`H# fS~  
B|cA[  
\Ut6;  
//获得文件长度 wA?@v|,dZ  
public long getFileSize() nIfN"  
{ 'UY[ap  
int nFileLength = -1; ]EB6+x!G  
try{ YecT 96%  
URL url = new URL(siteInfoBean.getSSiteURL()); ?qk@cKS  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 7^ 4jcfJH  
httpConnection.setRequestProperty("User-Agent","NetFox"); g[/^cJHQ  
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*"1~b
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int responseCode=httpConnection.getResponseCode(); ; ;<J x.  
if(responseCode>=400) l`SK*Bm~<  
{ ./$ <J6-J  
processErrorCode(responseCode); 5^\m`gS  
return -2; //-2 represent access is error $fj])>=H  
} A2Q[%A  
M]c7D`%s  
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String sHeader; "37*A<+f  
+H7y/#e+3  
*5e<\{!  
for(int i=1;;i++) }04Dg'  
{ S|HY+Z6n'  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Ba<ngG !  
//Utility.log(in.readLine()); SU/G)&Mi  
sHeader=httpConnection.getHeaderFieldKey(i); ;t}'X[U  
if(sHeader!=null) z1F9$^  
{ &]w#z=5SXi  
if(sHeader.equals("Content-Length")) x8Q~VVZr  
{ l$F_"o?&S@  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); l{8CISO*  
break; VSh!4z1  
} bZiyapM  
} Y+FP  
else qYx!jA]O  
break; B$ui:R/ t  
} pjACFVMFX  
} zt?h^zf}  
catch(IOException e){e.printStackTrace ();} 0A.PD rM:  
catch(Exception e){e.printStackTrace ();} 2xDQ:=ec  
J==}QEhQ{  
?FN9rhAC  
Utility.log(nFileLength); ^\MhT)x  
B22b&0  
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return nFileLength; @: Z#E[N H  
} {(;B5rs  
a2o.a2  
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//保存下载信息（文件指针位置） EJ G2^DSS  
private void write_nPos() /9pbnzn  
{ X<Z(]`i  
try{ mmHJh\2v
 
output = new DataOutputStream(new FileOutputStream(tmpFile)); V~85oUc\-  
output.writeInt(nStartPos.length); GA\2i0ow  
for(int i=0;i<nStartPos.length;i++) Tw
x{' S  
{ H<,bq*@  
// output.writeLong(nPos); Uj,g]e8e  
output.writeLong(fileSplitterFetch.nStartPos); *6XRjq^#  
output.writeLong(fileSplitterFetch.nEndPos); EY~7oNfc`R  
} ! tGiTzzp  
output.close(); UxeL cUP  
} ABcBEv3  
catch(IOException e){e.printStackTrace ();} [m\,+lG?)j  
catch(Exception e){e.printStackTrace ();} k{a)gFH O  
} k d+l k:  
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//读取保存的下载信息（文件指针位置） G]-%AO{K  
private void read_nPos() 7%4.b7Q  
{ 7,h3V=^)Q  
try{ Qwv '<  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 9\AS@SH{^T  
int nCount = input.readInt(); wlrIgn%  
nStartPos = new long[nCount]; VG)="g[%)  
nEndPos = new long[nCount]; uJY.5w  
for(int i=0;i<nStartPos.length;i++) S6GMUaR  
{ #&V5H{  
nStartPos = input.readLong(); [t{](-  
nEndPos = input.readLong(); .a:Z!KF  
} VD/&%O8n  
input.close(); 9<l-NU9 _  
} 088C|  
catch(IOException e){e.printStackTrace ();} ^>^\CP]  
catch(Exception e){e.printStackTrace ();} B7!;]'&d  
} KzG_ <<  
u
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private void processErrorCode(int nErrorCode) 7/?DPwbx  
{ "Hht g:  
System.err.println("Error Code : " + nErrorCode); 9 ZGV%Tw  
} aM$=|
%9/  
wWTQ6~Y%d  
'0RRFO  
//停止文件下载 Ff<)4`J  
public void siteStop() r1G8]agO  
{ 4\ FP  
bStop = true; |'<vrn  
for(int i=0;i<nStartPos.length;i++) xl8#=qmCD  
fileSplitterFetch.splitterStop(); 5mavcle{4r  
sLi*SR  
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} @Dj:4  
} c4 5?St  
//负责部分文件的抓取 @8zT'/$  
**FileSplitterFetch.java dF e4K"  
*/ (;
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package NetFox; )[jy[[K(  
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import java.io.*; ~C|,b"  
import java.net.*; E0YU[([G  
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public class FileSplitterFetch extends Thread { Q>=-ext}q  
*H"aOT^{  
y9!:^kDI  
String sURL; //File URL ;Iq5|rzDn  
long nStartPos; //File Snippet Start Position K_#UZA< Y  
long nEndPos; //File Snippet End Position uNbIX:L,  
int nThreadID; //Thread's ID {y6C0A*  
boolean bDownOver = false; //Downing is over 5 `=KyHi:b  
boolean bStop = false; //Stop identical D0ruTS  
FileAccessI fileAccessI = null; //File Access interface TsD;Kl1  
v459},!P  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException + |C=ZU  
{ ^f|<R8`  
this.sURL = sURL; -~O/NX  
this.nStartPos = nStart; o/1JO_41  
this.nEndPos = nEnd; RZh}:  
nThreadID = id; X+iK<F$  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 &@6 GI<  
} g$w6kz_[  
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public void run() e+@xsn3  
{ QNArZ6UQ  
while(nStartPos < nEndPos && !bStop) ,|pp67  
{ t$ZkdF  

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try{ )GJP_*Ab  
URL url = new URL(sURL); Qh-4vy=r  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ,I`_F,  
httpConnection.setRequestProperty("User-Agent","NetFox"); tD-gc''H  
String sProperty = "bytes="+nStartPos+"-"; _wh
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httpConnection.setRequestProperty("RANGE",sProperty); |<(t}}X  
Utility.log(sProperty); a$m_D!b~_  
9m8ee&,  
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InputStream input = httpConnection.getInputStream(); FT.@1/)  
//logResponseHead(httpConnection); ~`R1sSr"  
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byte[] b = new byte[1024]; !ZrB^?sO  
int nRead; |$e:*  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) /U*yw5  
{ 4j3oT)+8  
nStartPos += fileAccessI.write(b,0,nRead); rk,p!}FqL  
//if(nThreadID == 1) H]Wp%"L  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); _7@z_i_c  
} ^i`*Wm@!  
h|p[OecG  
J]fS({(\I  
Utility.log("Thread " + nThreadID + " is over!"); |zpx)8Q  
bDownOver = true; :;4SQN{2 O  
//nPos = fileAccessI.write (b,0,nRead); yvxl_*Ds8  
} A5XR3$
5P  
catch(Exception e){e.printStackTrace ();} r1Z<:}ZwK  
} r)b<{u=]  
} {?i)K X^  
D{C:d\ e)$  
J^ ={}  
//打印回应的头信息 cy1jZ1)  
public void logResponseHead(HttpURLConnection con) doD>m?rig3  
{ TpP8=8_Lh  
for(int i=1;;i++) <AUWby,"  
{ /s[DI;M$o  
String header=con.getHeaderFieldKey(i); 'ere!:GJD  
if(header!=null) 
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//responseHeaders.put(header,httpConnection.getHeaderField(header)); Q4wc-s4RN  
Utility.log(header+" : "+con.getHeaderField(header)); lLCdmxbT  
else 254~:eB0  
break; 8i:[:Z  
} a)9
rs\Is{  
} 16$y`~c-z  
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public void splitterStop() l h/&__  
{ M<[?g5=#  
bStop = true; CgnXr/!L  
} %MJ;Q?KB  
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} (1){A8=?o  
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/* 84
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**FileAccess.java CLN+I'uX0  
*//文件访问(定位，写) %S#WPD'Y  
package NetFox; >&Fa(o;*  
import java.io.*; Vk7=7%xW  
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;&?pd"^<_Z  
public class FileAccessI implements Serializable{ A/ 0qk  
?63&g{vA  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 \##`pa(8  
RandomAccessFile oSavedFile; +v15[^F  
long nPos;  Q2\  
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public FileAccessI() throws IOException Y\?j0X;  
{ arh@`'Q  
this("",0);  @E_zR  
} ^ vbWRG~  
2F?kjg,  
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public FileAccessI(String sName,long nPos) throws IOException h0VzIuV  
{ uD)-V;}P@;  
oSavedFile = new RandomAccessFile(sName,"rw"); a$}mWPp+f  
this.nPos = nPos; W9R`A  
oSavedFile.seek(nPos); o^ h(#%O  
} _V@P-Ye  
#WufZ18#  
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public synchronized int write(byte[] b,int nStart,int nLen) 2u:4$x8  
{ -<W2PY<  
int n = -1; m0( E kK  
try{ #Lka+l;L7  
oSavedFile.write(b,nStart,nLen); i'tp1CI  
n = nLen; SRz&Nb  
} TzM=LvA  
catch(IOException e) 2Qay
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{ \G;CQV#{9  
e.printStackTrace (); 7g6RiH}  
} L11L23:  
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return n; =! mJG  
} ,Y!zORv<7  
@ajM^L!O  
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} :vQM>9l7  
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/* 3Gd0E;3sk~  
**SiteInfoBean.java I@./${o  
*/ }uQ${]&D  
package NetFox; Do;#NLrWb  
=nhzMU9c\y  
JO1 ,TtA  
public class SiteInfoBean { Ew4g'A:H  
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private String sSiteURL; //Site's URL |.w;r   
private String sFilePath; //Saved File's Path arj$dAW  
private String sFileName; //Saved File's Name Q}P-$X+/ n  
private int nSplitter; //Count of Splited Downloading File j Z'&0x"U  
- L~Uu^o  
Tf-CEHWD  
public SiteInfoBean() uec|S\~M  
{//nSplitter的缺省值为5 }lfn0 %(@  
//default value of nSplitter is 5 %v4 [{ =fE  
this("","","",5); \ 4gXY$`@  
} MUcNC\`z  
7rIlTrG  
nW5K[/1D  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ]Oso#GYD  
{ >saI+u'o  
sSiteURL= sURL; h4 vm{ho  
sFilePath = sPath; ~:2K#q5C  
sFileName = sName; 8:{q8xZ=k  
this.nSplitter = nSpiltter; tWk{1IL  
zM59UQU;  
A&N*F"q  
} Sdc*rpH"(  
}O*WV1  
V/bH^@,sA  
public String getSSiteURL() ~`Sle xK|}  
{ C1QWU5c v  
return sSiteURL; j>!sN`dBj  
} Kbas-</Si  
\"d?=uFe  
?}sOG?{  
public void setSSiteURL(String value) o#e7,O  
{ j'Wp
  
sSiteURL = value; SE!L :  
} e1P7 .n}  
7a<_BJXx  
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public String getSFilePath() n`<U"$*  
{ (,LL[&;:  
return sFilePath; M 9"-WIG@h  
} 2Xgx*'t\  
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d@g2k> >  
public void setSFilePath(String value) #F4X}  
{ |s|/]aD}o  
sFilePath = value; YMu)  
} a8JN
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}W}G X(?P  
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public String getSFileName() ,qy&|4Jz  
{ WQt5#m; W  
return sFileName; %fpsc_  
} =pp:j`B9(  
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F^rl$#pCS  
public void setSFileName(String value) AgsR-"uh  
{ Zh,]J `  
sFileName = value; p&5S|![\  
} 1+^n!$  
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AbZ:(+@cP  
public int getNSplitter() XV5
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{ U;gp)=JNT  
return nSplitter; 4$Pr|gx  
} /*P7<5n0  

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public void setNSplitter(int nCount) &<h?''nCy  
{ o+^Eu}[.  
nSplitter = nCount; vYzVY\   
} %#9P?COs&W  
} ~4^p}{  
@1.9PR$x  
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/* ][t6VA  
**Utility.java owMmCR  
*/ & rQD`E/  
package NetFox; |EeBSRAfe  
o7arxo\  
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public class Utility { V}:'Xgp*N  
;
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public Utility() CJA+v-  
{ KZ3B~#oQ  
w\DspF  
\G3!TwC%  
} [B,p,Q"  
2 `&<bt[g  
//线程睡眠 dXO=ZU/N  
public static void sleep(int nSecond) CWvlr nv  
{ n?Zf/T  
try{ Y)OBTX  
Thread.sleep(nSecond); M5u_2;3  
} o=mo/N4  
catch(Exception e) wA",SBGX  
{ B^m!t7/,  
e.printStackTrace (); M[z3 f  
} xgs@gw7!n0  
} yjd(UWE  
YZ\@)D;  
//日志 GBr,LN  
public static void log(String sMsg) nNs .,J)  
{ [`9^QEj  
System.err.println(sMsg); *;X-\6  
} `sxN!Jj?  
Nm"<!a<F  
C9pnU,[  
public static void log(int sMsg) N(BiOLZL6  
{ j%5a+(H,z;  
System.err.println(sMsg); en%B>]QI  
} J7m`]!*t  
} ?\M)WDO  
mR,O0O}&  
]|y}\7Aa  
/* a7=YG6[  
**TestMethod.java {\Ys@FF  
*/ @E(P9zQ/zy  
package NetFox; V" }*"P-%  
6lZGcRO  
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public class TestMethod { F-tFet  
Se/ss!I
f  
9.]
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public TestMethod() ,\}k~ U99  
{ ///xx/weblogic60b2_win.exe ()B7(Y  
try{ 9R>~~~{-Go  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); r},lu=em  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); + "zYn!0  
SiteFileFetch fileFetch = new SiteFileFetch(bean); S[sr'ZW  
fileFetch.start(); }{t3SGsJ  
} <K,[sy&Qy  
catch(Exception e){e.printStackTrace ();} B6uRJcD4  
!^-OfqIHfV  
]f5c\\)  
} &~}@u[=ux  
S[^nSF  
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public static void main(String[] args) u`+'lBE,  
{ v!KJ|c@m  
new TestMethod(); }Q;BQ2[  
} G}q<{<+$  
} q55M8B 4w  
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