http断点续传简单实现（java)

/* `JC!uc  
**SiteFileFetch.java uo0(W3Q *  
*/ N4Ym[l  
package NetFox; eWFlJ;=  
import java.io.*; z}5XLa^  
import java.net.*; \%K6T)9  
!vU[V,~  
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public class SiteFileFetch extends Thread { = #`FXO1C  
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',.Xn`c  
SiteInfoBean siteInfoBean = null; //文件信息Bean ."2V:;;  
long[] nStartPos; //开始位置 .]" o-(gB  
long[] nEndPos; //结束位置 )}EwEM  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 87-oR}/r  
long nFileLength; //文件长度 QRRZMdEGs[  
boolean bFirst = true; //是否第一次取文件 P?I"y,_p  
boolean bStop = false; //停止标志 :r\<DVj  
File tmpFile; //文件下载的临时信息 f~53:;L/  
DataOutputStream output; //输出到文件的输出流 ALG +  
}"szL=s  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ,HkJ.6KF  
public SiteFileFetch(SiteInfoBean bean) throws IOException 35ng_,t$  
{ </fzBaTo  
siteInfoBean = bean; ^Tl|v'   
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); @+xQj.jNC  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); M|\XFO  
if(tmpFile.exists ()) \d6A<(!=v  
{ 4"GY0) Q  
bFirst = false; J9o]$.e  
read_nPos(); 0g1uM:;  
} vnKUD
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else 6(eyUgnb  
{ s}5;)>3~@  
nStartPos = new long[bean.getNSplitter()]; :/u EPki  
nEndPos = new long[bean.getNSplitter()]; 5nk]{ G> V  
} XX+4X*(o  
/m%;wH|6%  
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} M]oaWQu  
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public void run() WXJ%bH
  
{ se_1wCYz  
//获得文件长度 gg<lWeS/3  
//分割文件 /:B!hvpw  
//实例FileSplitterFetch -cMqq$  
//启动FileSplitterFetch线程 Obbjl@]  
//等待子线程返回 \h:$q E7  
try{ UF?qL1w  
if(bFirst) d^w6_  
{ Ug/b;( dJ'  
nFileLength = getFileSize(); qg|SBQ?6  
if(nFileLength == -1) 0DGXMO$;  
{ yAaMYF@  
System.err.println("File Length is not known!"); U1I2+;"#A  
} mzDbw-#  
else if(nFileLength == -2) @<h@d_8^k  
{ o4U9jU4<"  
System.err.println("File is not access!"); <"6}C)G  
} caS5>wk`R  
else oPl^tzO  
{ U4Il1| M&  
for(int i=0;i<nStartPos.length;i++) QO~!S_FRH  
{ @?TOg{:  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); iXI >>9  
} a:C
ly9  
for(int i=0;i<nEndPos.length-1;i++) G8j$&1`:
 
{ H|5\c=  
nEndPos = nStartPos[i+1]; Gq?JMq#  
} V
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nEndPos[nEndPos.length-1] = nFileLength; x:GuqE  
} qEE V
&  
} NU O9,  
|%Pd*yZA  
~~z}yCl  
//启动子线程 `i;f  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; <8~bb-U$  
for(int i=0;i<nStartPos.length;i++) M/T ll]\|  
{ BVU>M*k  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), q9|'!m5K  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), `5:b=^'D/  
nStartPos,nEndPos,i); 4~4D1  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); bs/Vn'CE  
fileSplitterFetch.start(); HZKqGkE  
} ogtl UCUD  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), c3lU  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); t 7dcaNBZ  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", w6aq/m"'  
nEndPos = " + nFileLength); o-c.D=~  
// fileSplitterFetch[nPos.length-1].start(); yJNQO'wcv  
D5^wT>3>  
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//等待子线程结束 R `  
//int count = 0; c<Fr^8  
//是否结束while循环 /?VwoSgV^  
boolean breakWhile = false; g[4pG`z  
vq=nG]cE)  
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while(!bStop) +8h!@  
{ XcLjUz?  
write_nPos(); q
8#zv_>K  
Utility.sleep(500); Qq+$ea?>  
breakWhile = true; x
}B3h9]  
OO#_0qK  
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for(int i=0;i<nStartPos.length;i++) opqY@>Vh&  
{ Y`3V&8X  
if(!fileSplitterFetch.bDownOver) 8#L V oR  
{ HtpZ5  
breakWhile = false; t>Lq "]1  
break; n<3qr}ZG^  
} m) QV2n  
} #g=7fu{n:  
if(breakWhile) wwaw|$  
break; B63puX{u#  
07b=Zhh  
&PZ&'N|P  
//count++; i24t$7q  
//if(count>4) eCFMWFhC  
// siteStop(); maTQ0G
X  
} 4 ))ZBq?  
;S0Kf{DN2  
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System.err.println("文件下载结束！"); ^pwT8Bp  
} 2fN2!OT  
catch(Exception e){e.printStackTrace ();} P8[rp  
} Sq:,6bcG  
6--t6>5  
\w#)uYK{i_  
//获得文件长度 G{CKb{  
public long getFileSize() FNlS)Bs  
{ '-X[T}  
int nFileLength = -1; Q-<h)WTA  
try{ 6pP:Q_U$  
URL url = new URL(siteInfoBean.getSSiteURL()); }iIZA
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); C2 4"H|D  
httpConnection.setRequestProperty("User-Agent","NetFox"); 'Y2ImSWj  
)[wB:kG  
z|bAZKSRYx  
int responseCode=httpConnection.getResponseCode(); /:B2-4>Q!  
if(responseCode>=400) 4g+Dp&U  
{ =aBc.PJ^  
processErrorCode(responseCode); "o)jB~:L  
return -2; //-2 represent access is error cY]BtJ#  
} hg7^#f95u  
Zz/ z7~{  
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String sHeader; xB`j* %  
}i$ER,hXh  
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for(int i=1;;i++) 9$f%  
{ +R"Y~ m{F  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); $:|?z_@  
//Utility.log(in.readLine()); Y[!s:3\f  
sHeader=httpConnection.getHeaderFieldKey(i); CFXr=.yz  
if(sHeader!=null) B@k2lHks(  
{ ?`T Q'#P`  
if(sHeader.equals("Content-Length")) mRO@ZY;5  
{ "*<)pnJ  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); G,!{Q''w  
break; P](/5KrK  
} .no<#l
 
} ULH<FDot  
else @)XR  
break; 9CG&MvF c  
} O@HL%ha  
} QpCTHpZ  
catch(IOException e){e.printStackTrace ();} (}m2}  
catch(Exception e){e.printStackTrace ();} U0=: `G2l  
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1R,SA:L$  
Utility.log(nFileLength); # Rhtaq9  
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return nFileLength; s}qtM.^W  
} p~WX\;  
 qC6@  
n|fKwWB\  
//保存下载信息（文件指针位置） ZZM;%i-B  
private void write_nPos() RiG]-K:  
{ #+&"m7 s  
try{ tH=jaFJ   
output = new DataOutputStream(new FileOutputStream(tmpFile)); ZZ>F ^t  
output.writeInt(nStartPos.length); GC`/\~TM  
for(int i=0;i<nStartPos.length;i++) v,|jmv+:  
{ [}I|tb>Pg  
// output.writeLong(nPos); wEZieHw  
output.writeLong(fileSplitterFetch.nStartPos); T]x]hQ  
output.writeLong(fileSplitterFetch.nEndPos); Q[Gs%/>  
} MFn\[J`Ra  
output.close(); "[ieOFI  
} M1=eS@  
catch(IOException e){e.printStackTrace ();} W2{4s 1  
catch(Exception e){e.printStackTrace ();} .On3ZN  
} h<G7ocu!  
; GEr8_7  
h t3P@;  
//读取保存的下载信息（文件指针位置） =6a=`3r!I  
private void read_nPos() !t[;~`d9  
{ qND:LP\_v  
try{ SohNk9u[8  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); E|3[$?=R  
int nCount = input.readInt(); </pt($  
nStartPos = new long[nCount]; @HE<\Z{ KI  
nEndPos = new long[nCount]; .P#t"oW}  
for(int i=0;i<nStartPos.length;i++) + B<7]\\M  
{ N6Dv1_c,  
nStartPos = input.readLong(); xb2j |KY7  
nEndPos = input.readLong(); *B)10R  
} NI
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input.close();
>9y!M'V  
} %?3$~d\n  
catch(IOException e){e.printStackTrace ();} H#M;TjR  
catch(Exception e){e.printStackTrace ();} 0a9[}g1=#  
} XVF!l>nE  
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private void processErrorCode(int nErrorCode) $F1Am%  
{ +7{8T{  
System.err.println("Error Code : " + nErrorCode); X4L@|"ZI  
} \0K&2'  
M< H+$}[  
.pG`/[*a  
//停止文件下载 558!?kx$  
public void siteStop() sf O{.#5<  
{ 5S[:;o  
bStop = true; x\IuM  
for(int i=0;i<nStartPos.length;i++) kZ;Y/DH  
fileSplitterFetch.splitterStop(); IOa@dUh7a,  
Wj8WT)cB  
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} PZY6 I  
} X/buz  
//负责部分文件的抓取 r?9".H  
**FileSplitterFetch.java 3e>U(ES  
*/ e~SRGyIww  
package NetFox; +i[@+`  
v|dt[>G  
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import java.io.*; ^A=2#
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import java.net.*; WD5jO9Oai  
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public class FileSplitterFetch extends Thread { ?4#  
]
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String sURL; //File URL 0EasPbp  
long nStartPos; //File Snippet Start Position >%5GMx>m  
long nEndPos; //File Snippet End Position l
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int nThreadID; //Thread's ID WpOH1[8v  
boolean bDownOver = false; //Downing is over g][n1$%  
boolean bStop = false; //Stop identical vsPIvW!V  
FileAccessI fileAccessI = null; //File Access interface S_ra8HY8  
5~$WSL?O)  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException zCv)%y  
{
 hOYX  
this.sURL = sURL; <nK@+4EH"o  
this.nStartPos = nStart; ~.#57g F"  
this.nEndPos = nEnd; (w`_{%T  
nThreadID = id; 0>"y)T3   
fileAccessI = new FileAccessI(sName,nStartPos);//定位 11Uu5e!.  
} pU<GI@gU  
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public void run() AF,;3G  
{ P F);KQ  
while(nStartPos < nEndPos && !bStop) 2km0  
{ HdyE`FY\  
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try{ }S4+1 U3  
URL url = new URL(sURL); %L$?Mey  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 8w#4T:hsuN  
httpConnection.setRequestProperty("User-Agent","NetFox"); 4pZKm-dM^  
String sProperty = "bytes="+nStartPos+"-"; ~+,ZD)AKi4  
httpConnection.setRequestProperty("RANGE",sProperty); jAovzZ6BL  
Utility.log(sProperty); `)kxFD_bH  
:2+z_+k}<  
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InputStream input = httpConnection.getInputStream(); ,Y16m{<eC  
//logResponseHead(httpConnection); \tA
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~fs} J  
#ApmJLeCO  
byte[] b = new byte[1024]; 4;(W0RQa  
int nRead; CtUAbR  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 9?^0pR p  
{ ]AZCf`7/?  
nStartPos += fileAccessI.write(b,0,nRead); ~jzT;9:  
//if(nThreadID == 1) .yHK  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); FbH@qHSH  
} ;kZJnN"y  
Q(R-8"  
Galh
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Utility.log("Thread " + nThreadID + " is over!"); m|;gl|dTB  
bDownOver = true; m8eoD{  
//nPos = fileAccessI.write (b,0,nRead); ;iQw2XhT  
} y-S23B
(  
catch(Exception e){e.printStackTrace ();} /XNC^!z6Js  
} -S&d5(
R  
} Zqv  
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IsVR4t]  
//打印回应的头信息 N7GZ'-t^Er  
public void logResponseHead(HttpURLConnection con) Hd
TB[(  
{ W"\+jHF"  
for(int i=1;;i++) sxdDI?W4  
{ ma/<#l^}  
String header=con.getHeaderFieldKey(i); r=xec@R]*  
if(header!=null) ys:F  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); )`2ncb   
Utility.log(header+" : "+con.getHeaderField(header)); - ^Y\'y2  
else `Gx 5=Bm;  
break; |oQhtk8.  
} m 0Uu2Z4  
} JdUI:(  
9H53H"5q  
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public void splitterStop() A;e"_$yt8  
{ `=kiqF2P}  
bStop = true; I]cZcx,<q  
} l[<o t9P[  
2Ky|+s[`[  
{bC(>k|CQ  
} fP- =wd  
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zQ+ %^DT1  
/* F3 g$b,RMH  
**FileAccess.java i?V:+0#q\]  
*//文件访问(定位，写) 7f*b5$+r  
package NetFox; |o^mg9  
import java.io.*; j'Gezx^.<e  
&g=6K&a$a  
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public class FileAccessI implements Serializable{ {cjp8W8hS  
?B`c<H"  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 .3wx}!:*|  
RandomAccessFile oSavedFile; Ci[Ja#p7$h  
long nPos; )EcfEym.>  
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public FileAccessI() throws IOException *ozXilO  
{ 
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this("",0); !u/c
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} i-4?]h k  
CUft  
%6&c3,?U\n  
public FileAccessI(String sName,long nPos) throws IOException &KV$x3  
{ B-|C%~fe  
oSavedFile = new RandomAccessFile(sName,"rw"); c0_512  
this.nPos = nPos; H2+V1J=  
oSavedFile.seek(nPos); -k%|sqDZj  
} ACI.{`SrQ=  
?\<Kb|Q  
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public synchronized int write(byte[] b,int nStart,int nLen) H1 i+j;RN  
{ Y~I0\8s-  
int n = -1; ?
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try{ > lI2r}  
oSavedFile.write(b,nStart,nLen); ^a|  
n = nLen; 0&3zBL%Bo  
} :#UA!|nV  
catch(IOException e) M?DXCsZ,)s  
{ $_|jI ^  
e.printStackTrace (); n8q%>.i7  
} Z5*O\kJv  
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return n; #?Ob->v  
} fJ%A_N}  
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} 20M]gw]  
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/* N0YJ'.=8,  
**SiteInfoBean.java awLSY:JI  
*/ GwG(?_I"  
package NetFox; MEtKFC|p  
V9;IH<s:  
Vp8!-[R  
public class SiteInfoBean { jk])S~xl?  
ph3dm\U.  
C2L=i3R  
private String sSiteURL; //Site's URL JycC\s+%E  
private String sFilePath; //Saved File's Path DRRy5+,I  
private String sFileName; //Saved File's Name }9Q<<
a  
private int nSplitter; //Count of Splited Downloading File &hWYw+yH\  
|KSoS#Y  
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public SiteInfoBean() +@do<2l]  
{//nSplitter的缺省值为5 `Tr !Gj_  
//default value of nSplitter is 5 %.:]4jhk  
this("","","",5); iP?lP= M  
} 7V"Jfh4_  
H$,wg!kY!  
NH,4>mV$!  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) %D ,(S-Uj  
{ 1Nz#,IdQ  
sSiteURL= sURL; $ \ I|6[P  
sFilePath = sPath; i>=y3x"  
sFileName = sName; x`K"1E{2  
this.nSplitter = nSpiltter; '~xjaa;.  
u}jC$T>2%6  
|+1k7S,  
} I.1(qbPkF+  
&qm:36Y7Xg  
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public String getSSiteURL() 0}\8
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{ k[1w] l8  
return sSiteURL; ItG|{Bo  
} n&E/{o(  
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public void setSSiteURL(String value) #aadnbf  
{ bFfDaO<k  
sSiteURL = value; V|;os  
} D ~NWP%H  
ASr3P5/  
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public String getSFilePath() %;O# y3,  
{ M:%L
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return sFilePath; XE;aJ'kt  
} rTeADu_vf  
"':SWKuMx  
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public void setSFilePath(String value) oN(F$Nvk  
{ ;!<@Fm9W  
sFilePath = value; ^;cJjl'=  
} (9+N_dLx~P  
r6e!";w:U  
ZRC7j?ui8`  
public String getSFileName() eie u|_  
{ 3\
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return sFileName; }ct*<zj[~u  
} XKbTjR  
5:l"*  
dg;E,'e_ p  
public void setSFileName(String value) P~@I`r567  
{ 'WoB\y569  
sFileName = value; P1"g62R  
} 9~}8?kPNw=  
/O$)m[  
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public int getNSplitter() #s-li b  
{ OLDEB.@  
return nSplitter; bpfSe  
} ~#iAW@  
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public void setNSplitter(int nCount) ~VJP:Y{[  
{ d6"B_,*b  
nSplitter = nCount; E>qehs,g  
} Bzr}+J  
} 58/\  
Y\{lQMCy  
76S>xnN  
/* rXnG"A  
**Utility.java GC~N$!*  
*/ ,CnUQx0  
package NetFox; /Pa<I^-#  
\J^xpR_0u  
V;]U]   
public class Utility { 20mZ{_%  
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.t{?doOT  
public Utility() .n)0@X!  
{ %gXNWxv  
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c]:@y"W5$  
} IV$2`)[A&X  
axd9b,  
//线程睡眠 ps=QVX)YP  
public static void sleep(int nSecond) g?!;04  
{ 7R".$ p  
try{ Mer\W6e"e  
Thread.sleep(nSecond); pPZ^T5-ks  
} /4u:5G  
catch(Exception e) 8\8%FSrc  
{ hin6cac  
e.printStackTrace (); p:8]jD@}%  
} kA&ul  
} h3kBNBI )  
P+;@?ofB  
//日志 =v/x&,Uj@6  
public static void log(String sMsg) M.}QXta  
{ .s<
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System.err.println(sMsg); 74*iF'f?c  
} "_/5{Nc$  
hdee]qLS  
vghn+P8  
public static void log(int sMsg) w^QqYUL${  
{ |)u|@\{  
System.err.println(sMsg); Q@#Gm9m  
} G3t 4$3|  
} 0B~Q.tyP  
@7<m.?A!  
>eaK@
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/* V3}$vKQ  
**TestMethod.java =6+j Po{F  
*/ N_>}UhZ
 
package NetFox; 1oIu~f{`  
wenJ(0L|  
%uhhQ<zs%  
public class TestMethod { RlTVx:  
)ur&Mnmm  
Q Ph6 p3bg  
public TestMethod() MBH/,Yd  
{ ///xx/weblogic60b2_win.exe &b&o];a  
try{ y2Z1B2E%f  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 5Ai$1'*p  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); J'y*>dW  
SiteFileFetch fileFetch = new SiteFileFetch(bean); H[8P]"*z*i  
fileFetch.start(); 1_.#'U>  
} MOW {g\{\  
catch(Exception e){e.printStackTrace ();} YJ^TO\4WM  
@Ao E>  
jj 9eFB  
} "t"&6\  
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public static void main(String[] args) cZXra(AD  
{ !4G<&hvb  
new TestMethod(); H=k*;'  
} v;@-bED(Qs  
} ;]^JUmxU[d  
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