http断点续传简单实现（java)

/* ;$!0pxL)s  
**SiteFileFetch.java `ALQSo~l  
*/ vcy+p]6KE-  
package NetFox; zYPvpZV/  
import java.io.*; _6nza)OFH  
import java.net.*; 
@$QtY(a  
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public class SiteFileFetch extends Thread { [A!=Hv_$  
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{![
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SiteInfoBean siteInfoBean = null; //文件信息Bean bDw\;bnG  
long[] nStartPos; //开始位置 b1e)w?n  
long[] nEndPos; //结束位置 :SF8t`4`  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 R*dXbI&,e  
long nFileLength; //文件长度 Ax!@vL&@  
boolean bFirst = true; //是否第一次取文件 TxkvHiq2  
boolean bStop = false; //停止标志 I[ZWOi\- ;  
File tmpFile; //文件下载的临时信息 uWXxK"J.  
DataOutputStream output; //输出到文件的输出流 $:DL+E-}  
0B`rTLwB  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） _#P5j#  
public SiteFileFetch(SiteInfoBean bean) throws IOException eBECY(QMQ  
{ g2r8J0v  
siteInfoBean = bean; =o"sBVj  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); %HZ!s `w_  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); X~; *zYd5  
if(tmpFile.exists ()) {2|sk9?W  
{ 5=MM^$QG  
bFirst = false; oFGgr2Re  
read_nPos(); :SD3  
} 6Vu??qBy  
else xdsF! Zb  
{ q=BAYZ\`  
nStartPos = new long[bean.getNSplitter()]; K,HR=5  
nEndPos = new long[bean.getNSplitter()]; =PBJ+"DQs  
} ^dhtc% W>  
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oB}rd9  
} \H
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public void run() n lvDMZ  
{ !%C&hH\  
//获得文件长度 \l;H!y[  
//分割文件 Q
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//实例FileSplitterFetch @)@hzXQ  
//启动FileSplitterFetch线程 GZFLJu  
//等待子线程返回 vr>Rd{dm  
try{ g!;
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if(bFirst) >\!>CuU  
{ xF9PjnWF=  
nFileLength = getFileSize(); f['pHR%l2$  
if(nFileLength == -1) A832z`  
{ O~g0R6M6e  
System.err.println("File Length is not known!"); h@?BA<'S  
} 6sRKbp|r7  
else if(nFileLength == -2) 3WdANR  
{ EabZ7zFoN  
System.err.println("File is not access!"); )/<\|mR  
} V$ss[fX  
else $y*["~TJ  
{ TBqJ.a  
for(int i=0;i<nStartPos.length;i++) e_pyjaY!s  
{ Ax+q/nvnb  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); V0WFh=CM@  
} |2~fOyA+  
for(int i=0;i<nEndPos.length-1;i++) AU +2'  
{ ^t\AB)(8  
nEndPos = nStartPos[i+1]; 7[ra#>e8'  
} pn~$u  
nEndPos[nEndPos.length-1] = nFileLength; "&/&v  
} FVcooV  
} 
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LA^H213N|  
3l@={Ts  
//启动子线程 BqKh&m  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; "i1~YE  
for(int i=0;i<nStartPos.length;i++) f[/E $r99J  
{ DNaU mz  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), x~tG[Y2F?  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), :bgi*pR{  
nStartPos,nEndPos,i); q|%(47}z  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); }0Q6iHX@  
fileSplitterFetch.start(); GxGZxf*(  
} tXTa>Q  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), rX#}2  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); =ITMAC\  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ^kMgjS}R  
nEndPos = " + nFileLength); ZIx,?E+eJ  
// fileSplitterFetch[nPos.length-1].start(); %!HmtpS  
J,E'F!{  
eID"&SSU  
//等待子线程结束 %o+VZEH3  
//int count = 0; |!)3[<.  
//是否结束while循环 g
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boolean breakWhile = false; ,g$N  
KPUc+`cN%  
:R<n{%~  
while(!bStop) 4PEJ}BW  
{ #$Z|)i]w  
write_nPos(); @"H+QVJ@  
Utility.sleep(500); !58-3F%P  
breakWhile = true; 16YJQ ue  
@fbB3  
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for(int i=0;i<nStartPos.length;i++) 4y+]V~p  
{ ge[+/$(1  
if(!fileSplitterFetch.bDownOver) U&/Jh^Yy  
{ o=2y`Eq  
breakWhile = false; xgtdmv%  
break; Tp`by 1s  
} % j7lLSusX  
} %9=^#e+pE  
if(breakWhile) ~OEP)c\k  
break; SN'LUwaMp!  
F#Oqa^$(  
M*E4:A9_M  
//count++; XWbe|K!e  
//if(count>4) #:3E.=  
// siteStop(); .c+RFX@0  
} BjJ$I^  
oG5JJpLT  
q'M-a tE.  
System.err.println("文件下载结束！"); o_EXbS]C  
} ,l`q  
catch(Exception e){e.printStackTrace ();} s%J|r{F6  
} `96:Z-!}  
kkFE9:[-c&  
l<{]%=Qg  
//获得文件长度 NJ7N*  
public long getFileSize() \A5cM\-  
{ >wM%|j'  
int nFileLength = -1; =[?2'riI  
try{ yc4mWB~gyU  
URL url = new URL(siteInfoBean.getSSiteURL()); ?ae:
9ZcH  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); VA)3=8
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httpConnection.setRequestProperty("User-Agent","NetFox"); %dS7u$Rnh  
((Ec:(:c  
_4rb7"b1  
int responseCode=httpConnection.getResponseCode(); @=b0>^\m  
if(responseCode>=400) <0R7uH  
{ JHc|.2Oe  
processErrorCode(responseCode);
OtF{=7  
return -2; //-2 represent access is error x"v5'EpL  
} _d]w)YMO  
i?'HVx  
brNe13d3~"  
String sHeader; @"kA&=0;|J  
N*lq)@smq  
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for(int i=1;;i++) Zo;@StN3}T  
{ }`IN5NdYp  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); A`=ESz  
//Utility.log(in.readLine()); q uv`~qn  
sHeader=httpConnection.getHeaderFieldKey(i); R/b)hP~  
if(sHeader!=null) -d%bc?  
{ Z,,Da|edH  
if(sHeader.equals("Content-Length")) iyu%o9_0  
{ @*q\$Eg}2  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ?9v!UT&#  
break; :{LVS nG  
} cIja^xD  
} )(\5Wk9(  
else WaN0$66[:  
break; ePIBg(  
} aAu upPu  
} 1b;Aru~l  
catch(IOException e){e.printStackTrace ();} .-`7Av+7  
catch(Exception e){e.printStackTrace ();} ~{Tus.jk  
.+ai dWd  
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Utility.log(nFileLength); REoFP;H~  
P)^K&7X  
RX=C)q2c  
return nFileLength; >Bskw2  
} =^q:h<  
0l.+yr}PE  
tV*g1)'zX  
//保存下载信息（文件指针位置） 6N
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private void write_nPos() R7x
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{
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try{ \KLWOj%  
output = new DataOutputStream(new FileOutputStream(tmpFile)); rNfu
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output.writeInt(nStartPos.length); ^z9ITGB~tV  
for(int i=0;i<nStartPos.length;i++) #?!)-Q%  
{ Xn$]DE/r}N  
// output.writeLong(nPos); f Nm Sx  
output.writeLong(fileSplitterFetch.nStartPos); /Kw
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output.writeLong(fileSplitterFetch.nEndPos); SG8|xoL  
} BA A)IQF  
output.close(); _ 97F  
} DD"]as"#  
catch(IOException e){e.printStackTrace ();} Tp)-L0kD_k  
catch(Exception e){e.printStackTrace ();} hP`3Ao  
} Z)62/`C)  
-g;iMqh#  
U,[vfSDGr  
//读取保存的下载信息（文件指针位置） :~zK0v"  
private void read_nPos() _s|C0Pt  
{ *1ku2e]z  
try{ 2P!Pbl<  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); f@[q# }6  
int nCount = input.readInt(); }j+ZF'#  
nStartPos = new long[nCount]; 2[r#y1ro  
nEndPos = new long[nCount]; Ls5|4%+&  
for(int i=0;i<nStartPos.length;i++) r$=iM:kERC  
{ 8g(%6 ET  
nStartPos = input.readLong(); SD8Q_[rY  
nEndPos = input.readLong(); 5z5#_*)O  
} |M)'@s:  
input.close(); (gvaYKvr  
} FGzB7w#  
catch(IOException e){e.printStackTrace ();} <[8at6;  
catch(Exception e){e.printStackTrace ();} tL 3]9qfj  
} o" &7$pAh  
-+Kx^V#'R  
\[B5j0vV,  
private void processErrorCode(int nErrorCode) vtCt6M  
{ \a<qI  
System.err.println("Error Code : " + nErrorCode); dE
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} ,wlFn  
]6GdB3?UVM  
:nCGqg  
//停止文件下载 $FNj>1  
public void siteStop() %gkRG66  
{ QyJ}zwD  
bStop = true; 9=ns.r  
for(int i=0;i<nStartPos.length;i++) C6M|A3^T  
fileSplitterFetch.splitterStop(); g.SFl  
(6^v`SZ  
(Z,v)TOXjV  
} :+bQ
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} q$(aMO&J  
//负责部分文件的抓取 5T:e4U&  
**FileSplitterFetch.java }XX)U_x  
*/ l"f.eo0@7  
package NetFox; ZMt9'w;  
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<wW#Wnc]  
import java.io.*; =XzrmPu  
import java.net.*; 4fT,/[k?  
b" 1a7  
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public class FileSplitterFetch extends Thread { iyB02\d  

K9njD#/  
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String sURL; //File URL l<ag\ d  
long nStartPos; //File Snippet Start Position r?nvJHP  
long nEndPos; //File Snippet End Position |cEJRs@B  
int nThreadID; //Thread's ID -Ds}kdxw  
boolean bDownOver = false; //Downing is over AME3hA  
boolean bStop = false; //Stop identical 6y)TXp  
FileAccessI fileAccessI = null; //File Access interface Pv17wUB  
?T3zA2  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException e=<knKc Q  
{ ^HgQ"dD <  
this.sURL = sURL; ` .|JTm[  
this.nStartPos = nStart; mKugb_d?  
this.nEndPos = nEnd; LBq~?Q.e  
nThreadID = id; 'Ybd'|t{}  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 '-oS=OrZ  
} 8UJK]_99I,  
12`q9Io"  
|_
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public void run() )h]~< fU  
{ ea kj>7\s  
while(nStartPos < nEndPos && !bStop) B7zyMh  
{ VgD z:j  
/{>$E>N;  

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try{ VG0Ty;bV  
URL url = new URL(sURL); Uy2NZ%rnt  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 3=5K7F  
httpConnection.setRequestProperty("User-Agent","NetFox"); ajC'C!"^Ty  
String sProperty = "bytes="+nStartPos+"-"; 9>yLSM,!rS  
httpConnection.setRequestProperty("RANGE",sProperty); $M{MOehZ  
Utility.log(sProperty); ?oana%  
7?!A~Seo|  
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InputStream input = httpConnection.getInputStream(); UF0W%Z  
//logResponseHead(httpConnection); 6_]-&&Nr  
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nr7#}pzo  
byte[] b = new byte[1024]; 2l]*><q|  
int nRead; r<VZEbm)  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) RfH.WXi  
{ l/1u>'  
nStartPos += fileAccessI.write(b,0,nRead); O<7Q>m  
//if(nThreadID == 1) !~Vo'ykwx'  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); wNo2$>*  
} <Hd8Jd4f  
c%y(Z5  
x\PZ.o  
Utility.log("Thread " + nThreadID + " is over!"); JjA3G`m=  
bDownOver = true; mApn[)?tv  
//nPos = fileAccessI.write (b,0,nRead); Y-!~x0-H  
} I><B6pIR  
catch(Exception e){e.printStackTrace ();} rPhx^ QKH2  
} o>WB,i^G  
} 9{[I|  
ffoL]u\  
z=mH\!  
//打印回应的头信息 %Ms"LoK  
public void logResponseHead(HttpURLConnection con) :rxS&5  
{ bfo..f-0/Y  
for(int i=1;;i++) w>#{Nl7gz  
{ Lx%*IE|c
 
String header=con.getHeaderFieldKey(i); KLb"_1z  
if(header!=null) aQ!QrTua-  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Nq]8p =e  
Utility.log(header+" : "+con.getHeaderField(header)); p7{2/mj  
else (=A61]yB  
break; &T.d"i  
} *JnY0xP  
} M3XG s|gw  
U ?iw  
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public void splitterStop() `wI$  
{ f^JiaU4 [  
bStop = true; YnR8mVo5Q  
} Ibf~gr(j  
;R5@]Hg6q  
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} *y+N-uq  
M)x6m|.=  
.lsD+}  
/* v~8CpC  
**FileAccess.java 6jw9p+.  
*//文件访问(定位，写) 5!QT }Um  
package NetFox; :g%hT$,]3b  
import java.io.*; J.EBt3  
$-D}y:  
(rmOv\hG9V  
public class FileAccessI implements Serializable{ GB%kxtGD;\  
jJY{np  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ZLj
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RandomAccessFile oSavedFile; t1JU_P  
long nPos;  =oE(ur  
/^]/ iTg  
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public FileAccessI() throws IOException tJG+k)EE  
{ 0g2?  
this("",0); }/w]+f*  
} dhX$b!DA  
&k@\k<2Ia  
(himx8Uml2  
public FileAccessI(String sName,long nPos) throws IOException 0OXl`V`w  
{ /Nc)bF%gX  
oSavedFile = new RandomAccessFile(sName,"rw"); z!M #  
this.nPos = nPos;
<4LW.q  
oSavedFile.seek(nPos); ["O_Phb|  
} C66
9:%  
.FN;3HU  
KqN;a i,F  
public synchronized int write(byte[] b,int nStart,int nLen) l4gF.-.GYF  
{ +v2)'?BS  
int n = -1; nt]'>eX_}  
try{ m#$$xG  
oSavedFile.write(b,nStart,nLen); 1> v(&;K  
n = nLen; D6dliU?k  
} ZEp>~dn;  
catch(IOException e) ;^TSla+t+  
{ fsl ZJE  
e.printStackTrace (); mm9uhlV8  
} O
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28LBvJVq@  
return n; 5DpvMhc_  
} }4g$aTc  
Q>q-6/|UX  
=]r2;014  
} :GN++\1pw  
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m-qu<4A/U|  
/* >~0~h:M+  
**SiteInfoBean.java b^
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*/ m-6&-G#  
package NetFox; **\?-*c=U  
8(Q|
[  
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public class SiteInfoBean { TCFr-*x  
'6kD6o_p1  
P5
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private String sSiteURL; //Site's URL x=Aq5*A0  
private String sFilePath; //Saved File's Path bU/4KZ'-^  
private String sFileName; //Saved File's Name aNn4j_V(  
private int nSplitter; //Count of Splited Downloading File !PA><F  
1 0zw}1x  
lUaJC'~p  
public SiteInfoBean() -dWg1`;  
{//nSplitter的缺省值为5 Qqi?DW1)-  
//default value of nSplitter is 5 }$'XV.  
this("","","",5); ?yxQs=&-q~  
} hH9~.4+*`g  
rq^%)tR  
8f<y~L_(`  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) /N({"G'  
{ S[gACEZ =  
sSiteURL= sURL; q'/o=De  
sFilePath = sPath; |g>
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sFileName = sName; fJP *RVz  
this.nSplitter = nSpiltter; UdVf/PGx  
gkX7,J-0  
`dD_"Hdt  
} {/(.Bpld  
D^2lb"3  
(c&%1bJ  
public String getSSiteURL() J>k 6`gw  
{ Q)y5'u qZ  
return sSiteURL; Zwz co  
} +I-BqA9  
u;]xAr1  
Ch3MwM5]  
public void setSSiteURL(String value) ?:M4GY"gV  
{ Gov.;hy  
sSiteURL = value; [Y$TVwFwX  
} Mvue>)g~>  
REgM  
YF-A8gXS  
public String getSFilePath() o$Ylqb#  
{ c_C
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return sFilePath; O_ZYm{T[7  
} G
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-%]1q#C>@  
@D!*@M6  
public void setSFilePath(String value) =-_hq'il  
{ {;E
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sFilePath = value; k0O5c[j  
} a??8)=0|}  
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public String getSFileName()
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{ t$~'$kM)<  
return sFileName; <&3aP}  
} yci}#,nb  
,~&HL7v  
b- e  
public void setSFileName(String value) Ncsh{.
  
{ $/|) ,n  
sFileName = value; r#2Fk&Z9  
} ^e <E/j{~  
;@Fb>lBhX  
M2w'cdHk  
public int getNSplitter() 0ug&HEl_w  
{ JKfJ%yy |  
return nSplitter; \lm]G7h  
} >$9
}"  
OA=~i/n~  
D*[Jrq,  
public void setNSplitter(int nCount) 1AN$s  
{ /5/gnpC  
nSplitter = nCount; 1%*\*z  
} 9]w?mHslE  
} #=S^i[K/  
"O0xh_Nr  
_K!.TM+9  
/* J{prI;]K  
**Utility.java t"YsIOT:O"  
*/ ]uypi#[  
package NetFox; R'zi#FeP  
[2Zy~`*y{  
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public class Utility { Y8]@y0(  
V`#
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public Utility() sH;_U)ssH  
{ }.E^_`  
z8awND  
T:Nk9t$W7@  
} vg[
3\!8z[  
d[p2?]  
//线程睡眠 5!fYTo|G>  
public static void sleep(int nSecond) M1xsGa9h&  
{ oo2d,  
try{ _Iav2=0Wi  
Thread.sleep(nSecond); ]q{_i  
} [V:~j1{3  
catch(Exception e) !|xB>d q?  
{ 'xj5R=V  
e.printStackTrace (); {~&Q"8 }G  
} 8\{z>y  
} ;J,(YNI 1  
[UI>SN  
//日志 "W%YsN0  
public static void log(String sMsg) r4X}U|s!0  
{ lMGO4U[z  
System.err.println(sMsg); 5X)M)"rq;V  
} wCNn/%C  
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`HQ)][  
public static void log(int sMsg) 94ruQ/   
{ pN5kcvQ  
System.err.println(sMsg); O8$~dzf,2  
} .
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} oC>J{z  
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3;BIwb_  
/* [m0X kvd  
**TestMethod.java EwN{|34C  
*/ &=kv69v  
package NetFox; U_5`  
1l#46?]~  
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public class TestMethod { Mg`!tFe3  
n>q!m@ }<  
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public TestMethod() mYgfGPF`  
{ ///xx/weblogic60b2_win.exe _Pqq*  
try{ f_S$CFa@  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 3Xu|hkK\e  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); mEd2f^R  
SiteFileFetch fileFetch = new SiteFileFetch(bean); T\}U{9ELL  
fileFetch.start(); (V6bX]<  
} Ldz]FB|  
catch(Exception e){e.printStackTrace ();} z:#]P0  
M<w
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(O0Ry2uk  
} )C8^'*!  
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!t2
3 _b0  
public static void main(String[] args) NLMvi!5w,  
{ ?`U_|Yo  
new TestMethod(); <x^$Fu
 
} H<_Tn$<zH.  
} -`k>(\Q<d  
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