http断点续传简单实现（java)

/* 97-=Vb  
**SiteFileFetch.java -xMM}r y  
*/ T.B}k`$  
package NetFox; *R8qnvE\()  
import java.io.*; I?#B_R#  
import java.net.*; DFN  
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public class SiteFileFetch extends Thread { +~l`rJ  
@(I)]Ca%O  
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SiteInfoBean siteInfoBean = null; //文件信息Bean Ua\<oD79]  
long[] nStartPos; //开始位置 yIG*  
long[] nEndPos; //结束位置 0OF]|hH  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 O od?ifA  
long nFileLength; //文件长度 l~j{i/>  
boolean bFirst = true; //是否第一次取文件 GkYD:o=qx  
boolean bStop = false; //停止标志 `bMwt?[*  
File tmpFile; //文件下载的临时信息 Q~>="Yiu  
DataOutputStream output; //输出到文件的输出流 QbG`F8dj  
b_%W*Q  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） u
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public SiteFileFetch(SiteInfoBean bean) throws IOException p({)ZU3  
{ y - Ge"mY  
siteInfoBean = bean; _;8+L\  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); O$$$1VHYo  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); NUb:5tL  
if(tmpFile.exists ()) +8eW/Bs@2  
{ 0{zA6Xu  
bFirst = false; ,W:Bh$%  
read_nPos(); e_z"<yq  
} ^e4y:#Nu  
else e,rCutA)  
{ jSMs<ox  
nStartPos = new long[bean.getNSplitter()]; [X=J]e^D  
nEndPos = new long[bean.getNSplitter()]; ;&?l1Vu  
} ^iz2=}Q8  
w/Ej>OS  
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} +:m'a5D
m  
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public void run() D`fi\A  
{ WlfS|/\%V^  
//获得文件长度 w$)E#|i  
//分割文件 6z>Zm1
h  
//实例FileSplitterFetch (25v7Y]  
//启动FileSplitterFetch线程 hY^-kdQ>M  
//等待子线程返回 {nyVC%@Y  
try{ e
lw}(l<F  
if(bFirst) E])X$:P?  
{ WTZr{)e  
nFileLength = getFileSize(); dX>l"))yR  
if(nFileLength == -1) tW7*(D  
{ m(c5g[6nO  
System.err.println("File Length is not known!"); e Zb8x  
} 3t^r;b  
else if(nFileLength == -2) L?~-<k  
{ ^"hsbk&Yu  
System.err.println("File is not access!"); ^d[s*,i?  
} p@x1B &Z  
else 6D n[9V  
{ +(9qAB7  
for(int i=0;i<nStartPos.length;i++) KtY_m`DY4R  
{ ecl$z6'c  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ee5QZ,  
} 8`j;v>2
 
for(int i=0;i<nEndPos.length-1;i++) l: X]$2;  
{ u%`4;|tI  
nEndPos = nStartPos[i+1]; 8E9W\@\  
} 2(Ez H  
nEndPos[nEndPos.length-1] = nFileLength; _O*"_^6  
} @vc
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} Mk"V%)1k  
{@gTs  
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//启动子线程 )$ +5imi  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; <^,5z!z}  
for(int i=0;i<nStartPos.length;i++) I];Hx'/<~  
{ V6{P41_  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Axtf,x+lH  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ,0=@cJ  
nStartPos,nEndPos,i); 3"
OD"  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); B U^3Ux$  
fileSplitterFetch.start(); ,'69RL?-Wg  
} u  teI[Q  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), (&x#VmDL  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); K[(h2&  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", &v
#*  
nEndPos = " + nFileLength); z9#iU>@  
// fileSplitterFetch[nPos.length-1].start(); 1*!`G5c,}  
*0aU(E#  
6 NJ5v+  
//等待子线程结束 "77 j(Vs9  
//int count = 0; `1$7. ydQ  
//是否结束while循环 R;*3";+v|:  
boolean breakWhile = false; T;u>]"S  
!pNY`sw}  
8yDu(.Q  
while(!bStop) 1Lf:TQB  
{ [|\JIr=of5  
write_nPos(); e2v[ma-  
Utility.sleep(500); J}-,!3qxW  
breakWhile = true; ,&\uuD&.
@  
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for(int i=0;i<nStartPos.length;i++) liUrw7,  
{ ?r,lgaw
 
if(!fileSplitterFetch.bDownOver) u}7#3JfLn  
{ ttwfWfX  
breakWhile = false; IaU  
break; uW8LG\Z>D5  
} W]UGo,  
} 6J|Y+Y$  
if(breakWhile) 4D`T_l  
break; v_gQCS  
1o;+.]B  
5$e|@/(0  
//count++; s C9j73vf  
//if(count>4) ]tVU$9D   
// siteStop(); tCk;tu!d  
} ">G|\_ZF  
q,JMmhWaT  
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System.err.println("文件下载结束！"); 0.~Pzg  
} w6fVZY4  
catch(Exception e){e.printStackTrace ();} 76\ir<1up  
} eoS8e$}  
\wxS~T<&L  
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//获得文件长度 pv=g)  
public long getFileSize() ;^Vsd\ac0  
{ K>h=  
int nFileLength = -1; 8gv\
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try{ aIv>X@U}  
URL url = new URL(siteInfoBean.getSSiteURL()); T'cahkSw'O  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); T #&9|  
httpConnection.setRequestProperty("User-Agent","NetFox"); L44/eyrp  
3+<}Hm+  
!po8[fz~x  
int responseCode=httpConnection.getResponseCode(); `5[d9z/6  
if(responseCode>=400) Bf;dp`(/
 
{ [lqwzW{(UN  
processErrorCode(responseCode); '*5I5'[ X,  
return -2; //-2 represent access is error
LFCcV<~  
} oyBBW?m  
;~
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Hb KJ&^  
String sHeader; SSKn7`  
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for(int i=1;;i++) iw\RQ 0  
{ ec:?Q0  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ISI\<qx  
//Utility.log(in.readLine()); 8'Z#sM^E  
sHeader=httpConnection.getHeaderFieldKey(i); "r!O9X6  
if(sHeader!=null) 0Ii* "?s  
{ dyRKmLb  
if(sHeader.equals("Content-Length")) r=<Oy1m/  
{ fQ5VRpWGn  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 1nb]~{l  
break; l@a>"\><i*  
} ca@0?q#  
} 9Xt5{\PJ  
else GqXnOmk  
break; {H+~4XG  
} >;eWgQ6V  
} J#7\R':}zl  
catch(IOException e){e.printStackTrace ();} 'ao<gTUbu  
catch(Exception e){e.printStackTrace ();} (PjC]`FK  
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}1P>^I"[Y  
Utility.log(nFileLength); IcMfZ{H1  
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return nFileLength; G[1:<Vg8  
} sr+* q6W  
Q# w`ZQX3  
cv(9v =](  
//保存下载信息（文件指针位置） C9[Jr)QX  
private void write_nPos() hPa:>e  
{ ^uIP   
try{ tCAh?nR  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 6eqxwj{S[  
output.writeInt(nStartPos.length); bT<if@h-  
for(int i=0;i<nStartPos.length;i++) n}MW# :eJe  
{ Yy6Mkw7X  
// output.writeLong(nPos); )-q#hY  
output.writeLong(fileSplitterFetch.nStartPos); dd#=_xe  
output.writeLong(fileSplitterFetch.nEndPos); \jDD=ew  
} ufE;rcYE  
output.close(); XBE+O7  
} A*jU&3#  
catch(IOException e){e.printStackTrace ();} M=$ qus  
catch(Exception e){e.printStackTrace ();} zdFO&YHTw  
} ?El8:zt?|  
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//读取保存的下载信息（文件指针位置） ,
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private void read_nPos() /EF0~iy  
{ SFVOof#s  
try{ 4.:2!Q  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); a>x3UVf_  
int nCount = input.readInt(); u}ULb F  
nStartPos = new long[nCount]; BbEWa  
nEndPos = new long[nCount]; "c8 -xG  
for(int i=0;i<nStartPos.length;i++) n,hl6[OL7  
{ P(BjXMd  
nStartPos = input.readLong(); Q>Rjv.1  
nEndPos = input.readLong(); m~cz  
} 5+*MqO>  
input.close(); o$]wd*+  
} x%Ph``XI  
catch(IOException e){e.printStackTrace ();} 7\>P@s
  
catch(Exception e){e.printStackTrace ();} b^[Ab:`}[V  
} ~.99H  
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private void processErrorCode(int nErrorCode) 22aS <@}  
{ 84v7g`lrR  
System.err.println("Error Code : " + nErrorCode); .{[+d3+,  
} $VOSd<87  
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//停止文件下载 *->2$uWP  
public void siteStop() bBwQ1,c$  
{ iV#sMJN9  
bStop = true; %M8m 8 )  
for(int i=0;i<nStartPos.length;i++) {;uOc{~+  
fileSplitterFetch.splitterStop(); 5}S~8  
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} w<=?%+n  
} t5: 1' N9P  
//负责部分文件的抓取 L?_'OwaY  
**FileSplitterFetch.java z,pKyInw  
*/ = F*SAz  
package NetFox; |>_e&}Y%L  
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import java.io.*; m)"gj**|y  
import java.net.*; Jbv66)0M  
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public class FileSplitterFetch extends Thread { $*N^bj  
*AK{GfP_  
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String sURL; //File URL !1G6ZC:z  
long nStartPos; //File Snippet Start Position L@9@3?  
long nEndPos; //File Snippet End Position @JB9qT  
int nThreadID; //Thread's ID \ZNUt$\  
boolean bDownOver = false; //Downing is over yW3!V-iA  
boolean bStop = false; //Stop identical RuyqB>[o  
FileAccessI fileAccessI = null; //File Access interface 'W'['TV  
9
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException EWz,K]_'  
{ 1eod;^AP9  
this.sURL = sURL; 'M20v-[  
this.nStartPos = nStart; TS2zzYE6Z  
this.nEndPos = nEnd; Xy(8}  
nThreadID = id; `Hlv*" w$  
fileAccessI = new FileAccessI(sName,nStartPos);//定位
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} :Vdo.uUa  
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public void run() w3hG\2)[HS  
{ olA 1,8  
while(nStartPos < nEndPos && !bStop) m2sf]-?Y  
{ {Xr|L  
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try{ Q[rmsk2L'  
URL url = new URL(sURL); O+f'Ql  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); {HF,F=W  
httpConnection.setRequestProperty("User-Agent","NetFox"); MBp,!_Q6  
String sProperty = "bytes="+nStartPos+"-"; ~F)[H'$A  
httpConnection.setRequestProperty("RANGE",sProperty); Qqm$Jl!  
Utility.log(sProperty); 9:\#GOg  
\eH`{Z'.x5  
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InputStream input = httpConnection.getInputStream(); Al93x  
//logResponseHead(httpConnection); 0NB5YQ8_]  
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byte[] b = new byte[1024]; G~.bi<(v  
int nRead; i>elK<R4  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) cc0e(\  
{ v35!? 5{  
nStartPos += fileAccessI.write(b,0,nRead); gdj,e ^  
//if(nThreadID == 1) :,8eM{.Q  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); E]MyP=g$  
} xZ\`f-zL  
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Utility.log("Thread " + nThreadID + " is over!"); Xi  8rD"v  
bDownOver = true; ;rvZ!/  
//nPos = fileAccessI.write (b,0,nRead); (Zi,~Wqm$  
} pw, <0UhV  
catch(Exception e){e.printStackTrace ();} s[dq-pc"  
} +.3,(l  
} a_V.mu6h6p  
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//打印回应的头信息 V#Pz`D  
public void logResponseHead(HttpURLConnection con) (_ TKDx_  
{ RCC~#b
b  
for(int i=1;;i++) bnZ`Wc*5b  
{ b<E0|VW  
String header=con.getHeaderFieldKey(i); c{(4s6D  
if(header!=null) KlbUs\E  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); _N1UL?  
Utility.log(header+" : "+con.getHeaderField(header)); P`$Y
73L  
else FfSKE  
break; L"x9O'U  
} h*lU&8)m\  
} uP.[,V0@^  
cedH#;V!j  
zNh$d;(O$^  
public void splitterStop() .dw;b~p  
{ .}*_NU   
bStop = true; _mG>^QI.  
} "k>;K,:  
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IEj=pI  
} C<B1zgX  
|M$ESj4@  
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/* k2Dq~zn  
**FileAccess.java 0s2@z5bfX  
*//文件访问(定位，写) _ry7[/)  
package NetFox; &60#y4  
import java.io.*; q% pjY  
/4{.J=R}  
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public class FileAccessI implements Serializable{ VGL!)1
b  
l(A>Rw|  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 \f-HfYG  
RandomAccessFile oSavedFile; /9k}Ip  
long nPos; =JDa[_lpN  
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public FileAccessI() throws IOException #- z(]Y,y  
{ r$/.x6g//  
this("",0); ^BN?iXQhN  
} K[Ao_v2g  
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public FileAccessI(String sName,long nPos) throws IOException X)^&5;\`  
{ MU#$tXmnC  
oSavedFile = new RandomAccessFile(sName,"rw"); RI0+9YJ  
this.nPos = nPos; -)o0P\cTEt  
oSavedFile.seek(nPos); $8t\|O3  
} Q%Y rm  
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ATq-&1hs  
public synchronized int write(byte[] b,int nStart,int nLen) .#wU+t>  
{ Ng;Fhv
+  
int n = -1; ufc_m4PN  
try{ /sa\Ze;E  
oSavedFile.write(b,nStart,nLen); 0Ik}\lcn  
n = nLen; ndxijqw  
} =k|hH~  
catch(IOException e) y|O)i I/g  
{ P;~P:qKd  
e.printStackTrace (); Ag@R60#  
} d\{a&\v  
X!=*<GF)  
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return n; lV)SOs$  
} i#1~<U  
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L|
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} QU%'z/dip  
:eR[lR^4*  
vp#r:+=  
/* +E-f  
**SiteInfoBean.java WC ZDS>  
*/ @ZFU< e$!  
package NetFox; NX5NE2@^qH  
uom~,k$|  
i
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public class SiteInfoBean { ;x~[om21;  
4}>1I}!k  
\&)k{P>=  
private String sSiteURL; //Site's URL |&xjuBC  
private String sFilePath; //Saved File's Path H,5##@X  
private String sFileName; //Saved File's Name ?ybX&V  
private int nSplitter; //Count of Splited Downloading File Pln*?o  
jy2@t*  
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public SiteInfoBean() f
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{//nSplitter的缺省值为5 ~hxo_&  
//default value of nSplitter is 5 r1!]<=&\  
this("","","",5); GP
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} /naGn@m5u  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) !YJ^BI    
{ /qalj\ud  
sSiteURL= sURL; nM,5KHU4a  
sFilePath = sPath; [AHZOA  
sFileName = sName; i<%  
this.nSplitter = nSpiltter; I-`qo7dQ_S  
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eODprFkt}
 
} ^68BxYUoD\  
c?1:='MC  
xw%'R-  
public String getSSiteURL() %hqhi@q#  
{ NA`E
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return sSiteURL; xK8R![x  
} S3(2.c~  
>|
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public void setSSiteURL(String value) [Y^1}E*  
{ <fLk\ =  
sSiteURL = value; I$7TnMug  
} 6qgII~F'  
^-'t`mRl]d  
->S6S_H/+&  
public String getSFilePath() EjYCOb-  
{ M+N7JpR  
return sFilePath; koizk&)  
} W%k0_Y/5  
P=jbr"5Q:  
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public void setSFilePath(String value) ZdJer6:Z}  
{ }ST0?_0F*  
sFilePath = value; E*t0ia8  
} U.@j!UrZ  
;%R+]&J  
`Y`QxU!d%  
public String getSFileName() pdrF/U+  
{ L'JEkji"  
return sFileName; 7v~\c%1V  
} F ;m1I+;  
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public void setSFileName(String value) W]v[Xm$q  
{ Je6=N3)  
sFileName = value; oVc l (  
} r|WoM39bp  
0*.> >rI  
:K)=Hf2y  
public int getNSplitter() 9N[vNg<n  
{ @zJhJ'~Sl  
return nSplitter; AjQ^ {P  
} M zLx2?  
7 vS]O$w<4  
?=]*r>a3  
public void setNSplitter(int nCount) Q(}TN,N  
{ ~!,Q<?  
nSplitter = nCount; <p'~$vK  
} 9%?'[jJ  
} h69: Tj!  
\c! LC4pE  
FH'jP`  
/* N>fC"  
**Utility.java xwH+Q7O&l  
*/ SRN:!-  
package NetFox; !S/hH%C  
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KJwkkCE/=  
public class Utility { I]`>m3SJ  
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public Utility() PUUBn"U-  
{ P7I,xcOm  
`ecuquX'  
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} dJ#. m  
!Cj1:P  
//线程睡眠 :zC'jceO  
public static void sleep(int nSecond) m
<
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{ ,uD>.->  
try{ 2&W(@wT$  
Thread.sleep(nSecond); -A
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} F*QD\sG:  
catch(Exception e) =GQ?P*x|$  
{ }0#cdw#gH  
e.printStackTrace (); cz/mUU  
} ?wps_XU  
} lHpo/R:  
[)`9euR%  
//日志 *|x2"?d-F:  
public static void log(String sMsg) -#b-@sD  
{ -;z&">  
System.err.println(sMsg); Q^v8n1  
} *n0k2 p  
WT!8.M;Kv  
#[*e$C  
public static void log(int sMsg) FeS6>/  
{ $}S5&  
System.err.println(sMsg); zjh&?G]:G  
} '[p~| mX  
} 3MC| O5R4  
lX`)Avqa  
$&m^WrZaY  
/* nm*!#hx  
**TestMethod.java $7
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*/ lC6#EU;  
package NetFox; Kbc-$oneR  
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public class TestMethod { '?Q [.{<  
!&C8
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oJ`ih&Q8  
public TestMethod() `"m"qUd  
{ ///xx/weblogic60b2_win.exe gv;=Yhw.c  
try{ ?x@BZe  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ~?aq=T  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); @]dN   
SiteFileFetch fileFetch = new SiteFileFetch(bean); +*g[hRw[  
fileFetch.start(); 5.xvOi|.  
} <27B*C M  
catch(Exception e){e.printStackTrace ();} h^$>{0"  
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} ,u(g#T  
u *z$I  
1
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public static void main(String[] args) @l&5 |Cia  
{ 6.~(oepu  
new TestMethod(); P]+^
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} x}1(okc  
} V/|Ln*rm  
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