http断点续传简单实现（java)

/* *Ust[u  
**SiteFileFetch.java T? ,P*l  
*/ yl&UM qI(  
package NetFox; _`-1aA&n~  
import java.io.*; l1=JrpCan  
import java.net.*; d' >>E  
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public class SiteFileFetch extends Thread { 2{,n_w?Wy  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ShOX<Fb&  
long[] nStartPos; //开始位置
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long[] nEndPos; //结束位置 ?`_jFj+<\S  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 yCz|{=7"j  
long nFileLength; //文件长度 d4?d4;{  
boolean bFirst = true; //是否第一次取文件 RIn9(r  
boolean bStop = false; //停止标志 FqFapRX66Z  
File tmpFile; //文件下载的临时信息 K*-@Q0"KM{  
DataOutputStream output; //输出到文件的输出流 $4SzUZ0  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ecJ6  
public SiteFileFetch(SiteInfoBean bean) throws IOException xw^.bz|  
{ 2.e vx  
siteInfoBean = bean; Y5q3T`xE  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); SGc8^%-`  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); o|pT;1a"  
if(tmpFile.exists ()) >JwLk[=j  
{ ;lX(}2tXW  
bFirst = false; E.bi05l  
read_nPos(); sW#JjtK  
} PCrU<J 7  
else }G<T:(a  
{ `lDut1J5n  
nStartPos = new long[bean.getNSplitter()]; P(k(m<0  
nEndPos = new long[bean.getNSplitter()]; z&8un%Jt  
} `6Qdfmk=  
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} tvKAIwe  
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public void run() "t=hzn"~%  
{ Joe_PS  
//获得文件长度 SlLw{Yb7\.  
//分割文件 R8ONcG  
//实例FileSplitterFetch oPKr* `'  
//启动FileSplitterFetch线程 K0+.q?8D|  
//等待子线程返回 7xo4-fIuT  
try{ 
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if(bFirst) QYb33pN|  
{ V&]DzjT/  
nFileLength = getFileSize(); pE.PX 8  
if(nFileLength == -1) -5l6&Y   
{ |C%Pjl^YkV  
System.err.println("File Length is not known!"); Scm36sT{  
} qm*}U3K  
else if(nFileLength == -2) .9[45][FK  
{ [k$*4u>  
System.err.println("File is not access!"); CI:^\-z  
} o KD/rI  
else m(iR
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{ Q:C$&-$  
for(int i=0;i<nStartPos.length;i++) :K82sCy%5  
{ ^i)hm  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ''OfS D_g  
} lS^(&<{  
for(int i=0;i<nEndPos.length-1;i++) =,!\~`^  
{ m9}AG Rj  
nEndPos = nStartPos[i+1]; p}b/XnV$~  
} q-ES6R  
nEndPos[nEndPos.length-1] = nFileLength; W,@ If}  
} &5{xXWJK  
} mV^Zy  
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S\6[EQ65  
//启动子线程 >gKh  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; @XD+'{]  
for(int i=0;i<nStartPos.length;i++) ]{~NO{0@Y  
{ [[~w0G~1  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), g42)7  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), `cQo0{xK  
nStartPos,nEndPos,i); F 09DV<j  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); $eV$2p3H  
fileSplitterFetch.start(); :4S%'d7  
} pCpb;<JG  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 4F>Urh+  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); I V%VU  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", )Rat0$6  
nEndPos = " + nFileLength); 8n BL\{'B[  
// fileSplitterFetch[nPos.length-1].start(); Ioy  
8mLP5s!7  
L\{IljA  
//等待子线程结束 Lj\/Ji_  
//int count = 0; ik|-L8  
//是否结束while循环 7+TiyY]K  
boolean breakWhile = false; S_T^G` [  
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F;lI+^}}  
while(!bStop) depYqYK7G  
{ WnUweSdW  
write_nPos(); aq+Y7IR_  
Utility.sleep(500); "jecsqCgK0  
breakWhile = true; :f5s4N  
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for(int i=0;i<nStartPos.length;i++) "TV(H+1,z  
{ !J*,)kRN  
if(!fileSplitterFetch.bDownOver) {HC@u{K-  
{ E Uar/  
breakWhile = false; -5>-%13  
break; G'zF)0oD  
} ;VO.!5W@eg  
} aKUS5jDu  
if(breakWhile) ;?}l  
break; XS0xLt=  
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//count++; ``,k5!a66\  
//if(count>4) 3lLMu B+  
// siteStop(); BYW^/B Y)  
} @''GPL@  
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System.err.println("文件下载结束！"); <D&)OxEn\  
} =z?%;4'|  
catch(Exception e){e.printStackTrace ();} &bqT/H18  
} }7G8|54t  
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//获得文件长度 "x941}  
public long getFileSize() Z34Wbun4  
{ KV|}#<dD  
int nFileLength = -1; )2UZ% ?V#  
try{ 2Nxm@B` {  
URL url = new URL(siteInfoBean.getSSiteURL()); :{'k@J"|a  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); U7xmC  
httpConnection.setRequestProperty("User-Agent","NetFox"); qjJBcu_C'S  
}pkj:NT  
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int responseCode=httpConnection.getResponseCode();  %dErnc$  
if(responseCode>=400) Iu~\L0R427  
{ zL5d0_E9  
processErrorCode(responseCode); 8,O33qwH  
return -2; //-2 represent access is error %xlqF<  
} v{i7h|e  
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String sHeader; d0hhMx6$  
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for(int i=1;;i++) Obw?_@X  
{ Z3;!l  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); C8#@+Q.  
//Utility.log(in.readLine()); wOQ#N++
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sHeader=httpConnection.getHeaderFieldKey(i); <?D[9Mk$  
if(sHeader!=null) IfO;S*Qt  
{ *F>v]8  
if(sHeader.equals("Content-Length")) vN4Qdpdb  
{ 30PZ{c&Rll  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 1tCQpf  
break; H7+X&#s%  
} E^_wI>  
} {Z;jhR,  
else D2YZ9e
  
break; B:"THN^  
} DlMe5=n-u  
} #X: 'aj98  
catch(IOException e){e.printStackTrace ();} D3Jr3 %>  
catch(Exception e){e.printStackTrace ();} 53HU.  
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Utility.log(nFileLength); S1n3(U:m  
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return nFileLength; ` b !5^W  
} *O:r7_ Y0  
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//保存下载信息（文件指针位置） ?^' 7+8C*J  
private void write_nPos() UE _fpq  
{ _u"nvgVz9  
try{ zeP}tzQO  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 9[v1h,L  
output.writeInt(nStartPos.length); C\_zdADUb%  
for(int i=0;i<nStartPos.length;i++) N_4eM,7t  
{  6,1b=2G  
// output.writeLong(nPos); *KK+X07  
output.writeLong(fileSplitterFetch.nStartPos); rI5Foh6  
output.writeLong(fileSplitterFetch.nEndPos); vgn@d,v  
} QU{Ech'  
output.close(); r8xyd"Axy  
} * v8Ts  
catch(IOException e){e.printStackTrace ();} ~/_9P Fk  
catch(Exception e){e.printStackTrace ();} )oo~m\`  
} 3qHQX?a  
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//读取保存的下载信息（文件指针位置） oq-<ob  
private void read_nPos() d;tkJ2@NO  
{ 2y0J`!/)  
try{ E< 4l#Z<  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); tg4Y i|5  
int nCount = input.readInt(); zWw2
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nStartPos = new long[nCount]; w)E@*h<Z  
nEndPos = new long[nCount]; VS#wl|b8  
for(int i=0;i<nStartPos.length;i++) 6Dws,_UAZ4  
{ 0YH+B
 
nStartPos = input.readLong(); B}OY/J/*8  
nEndPos = input.readLong(); Gx?+9CV  
} p6EDQwlf  
input.close(); ^x*nq3^h\  
} 4A{|[}!  
catch(IOException e){e.printStackTrace ();} nU+tM~C%a  
catch(Exception e){e.printStackTrace ();} g}&hl"j  
} k.h`Cji@  
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private void processErrorCode(int nErrorCode) IWVlrGyM  
{ t<uYM  
System.err.println("Error Code : " + nErrorCode); fBBa4"OK=  
} 8$xPex~2  
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fkfZ>D^1  
//停止文件下载 ?wMHS4  
public void siteStop() K*K1(_x=  
{ 5_K5?N  
bStop = true; F}Mhs17!|  
for(int i=0;i<nStartPos.length;i++) G DSfT{kK\  
fileSplitterFetch.splitterStop(); ,F+B Wot4  
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} 'f8(#n=6qP  
} -0o[f53}p  
//负责部分文件的抓取 c- $Gpa}M  
**FileSplitterFetch.java '2J0>Bla  
*/ /4=-b_2Y~  
package NetFox; C`oa3B,z  
si1*Wt<3Bc  
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import java.io.*; 71FeDpe  
import java.net.*; 6XEZ4Q
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public class FileSplitterFetch extends Thread { (A k\Lm  
,zcQS-e2  
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String sURL; //File URL (J$\-a7<f  
long nStartPos; //File Snippet Start Position z^* '@  
long nEndPos; //File Snippet End Position <dA8 '7^  
int nThreadID; //Thread's ID pvWau1ArNq  
boolean bDownOver = false; //Downing is over dtM[E`PL  
boolean bStop = false; //Stop identical NQTnhiM7$  
FileAccessI fileAccessI = null; //File Access interface u'Q?T7  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException i;\s.wrzH  
{ WiNT;v[  
this.sURL = sURL; PL0`d`TI  
this.nStartPos = nStart; ~%w~-O2  
this.nEndPos = nEnd; TmRxKrRs  
nThreadID = id; fT:}Lj\L1  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 PsjbR  
} ]*"s\ix  
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public void run() /k\01hc`  
{ *xRc * :0  
while(nStartPos < nEndPos && !bStop) T*2C_oW  
{ 2H#N{>7  
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try{ D _X8-  
URL url = new URL(sURL); &!.HuRiuC  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); iMP  
httpConnection.setRequestProperty("User-Agent","NetFox"); -=$2p0"R  
String sProperty = "bytes="+nStartPos+"-"; dLh6:Gh8_I  
httpConnection.setRequestProperty("RANGE",sProperty); |fsm8t<~8  
Utility.log(sProperty); -*VKlZ8-  
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InputStream input = httpConnection.getInputStream(); d<p2/aA  
//logResponseHead(httpConnection); @B1{r|-<^  
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byte[] b = new byte[1024];  aA*9,  
int nRead; i`U:gw  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ( `' 8Ww  
{ Rz <OF^Iy  
nStartPos += fileAccessI.write(b,0,nRead); ;|ub!z9GG  
//if(nThreadID == 1) kka"C]!  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); _]#klL  
} +`en{$%%  
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Utility.log("Thread " + nThreadID + " is over!"); R|,7d:k  
bDownOver = true; G"s0GpvQ  
//nPos = fileAccessI.write (b,0,nRead); % +Pl+`?E  
} 0A$SYF$O+[  
catch(Exception e){e.printStackTrace ();} x/TGp?\g  
} <HoAj"xf  
} nnCug  
QEJGnl676  
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//打印回应的头信息 a%
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public void logResponseHead(HttpURLConnection con) QX0Y>&$)  
{ ;_JH:}j  
for(int i=1;;i++) 66:ALFwd7  
{ =G>(~+EA  
String header=con.getHeaderFieldKey(i); $3 8gs{+  
if(header!=null) 2hOPzv&B  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); I lG:X)V%  
Utility.log(header+" : "+con.getHeaderField(header)); \P?ToTTV  
else L/r{xS  
break; vE\lp8j+  
} 0Qd%iP)6  
} ym%slg  
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public void splitterStop() 1p\Ak  
{ z]#hWfM4B:  
bStop = true; B4W\ t{  
} 2"/yEg*=  
7 ^I:=qc72  
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} \KM|f9-b  
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/* v[#)GB _5  
**FileAccess.java cdp0!W4Gi  
*//文件访问(定位，写) D1"7s,Hmu  
package NetFox; uEd,rEB>  
import java.io.*; }p'8w\C$  
&4kM8Qh  
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public class FileAccessI implements Serializable{ F$Pp]"82'm  
K3ukYR  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 $Ub}p[L  
RandomAccessFile oSavedFile; U6{dI@|B  
long nPos; 4;<DJ.XlN=  
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public FileAccessI() throws IOException *8\(FVyG^  
{ nR'#s%Kj  
this("",0); *SZ>upg  
} }iNY_I c  
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public FileAccessI(String sName,long nPos) throws IOException \3^Pjx  
{ I'IB_YRL4  
oSavedFile = new RandomAccessFile(sName,"rw"); !<Z{@7oH  
this.nPos = nPos; a$+#V=bA  
oSavedFile.seek(nPos); @d)a~[pm  
} S}gD,7@  
3?ba 1F0Nw  
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public synchronized int write(byte[] b,int nStart,int nLen) tA qs2  
{ < l[
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int n = -1; `Cj,HI_/*  
try{ ryEvmWYu  
oSavedFile.write(b,nStart,nLen); t<lyg0f  
n = nLen; 5Rs?CVVb  
} r<(kLpOH%  
catch(IOException e) E^syrEz  
{ L?f qcW{  
e.printStackTrace (); 1URsHV!xcM  
} bOXh|u_3i  
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return n; cEi<}9r  
} tc/jY]'32  
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} >sV Bj(f  
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/* LW?2}`+  
**SiteInfoBean.java /nM*ljfB\  
*/ 4~WlP,,M  
package NetFox; Kq6qXc\x  
WguV{#=H  
6DZ2pT:  
public class SiteInfoBean { a}D&$yz2  
X,53c$  
t^$Div_%G  
private String sSiteURL; //Site's URL g.&\6^)8p  
private String sFilePath; //Saved File's Path L&HzN{K  
private String sFileName; //Saved File's Name m?vAyi
  
private int nSplitter; //Count of Splited Downloading File ~y%7w5%Un  
Ja=N@&Z#  
*
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public SiteInfoBean() },3R%?89%  
{//nSplitter的缺省值为5 D4\(:kF\Hg  
//default value of nSplitter is 5 ]Hj`2\KD.d  
this("","","",5); zf")|9j  
} nP)-Y#`~7  
QQ|9>QP  
;S=e%:zb  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) A'v[SUW'm  
{ _Fvsi3d/  
sSiteURL= sURL; XAlD  ww  
sFilePath = sPath; EM~7#Y  
sFileName = sName; B2"+Hwbk  
this.nSplitter = nSpiltter; GD/nR4$  
c=<v.J@K  
%J3lK]bv(  
} A3!2"}L  
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public String getSSiteURL() D2-O7e  
{ <v-92?  
return sSiteURL; "lb\c  
} 6!
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LQ|<3]  
public void setSSiteURL(String value) Ae3#>[]{  
{ n]Ebwznt-  
sSiteURL = value; -*
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} C890+(D~  
E<P*QZ-C3  
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public String getSFilePath() _"`/^L`Q?  
{ P:vX }V |[  
return sFilePath; k.ww-nH  
} j[BgP\&,  
!-@SS>  
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public void setSFilePath(String value) r6/<&
1[  
{ s UvKA0  
sFilePath = value; ,7/\&X<`B  
} 4v i B=>  
;+!xZOmm  
sd7Y6?_C  
public String getSFileName() |HT)/UZ|  
{ |c BHBd  
return sFileName; Zj5NWzj X  
} pzYG?9cwz  
!vi4* @:  
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public void setSFileName(String value) LIc*tsl  
{ e1Dj0s?i~K  
sFileName = value; ]oo|o1H87  
} H==X0  
ook' u}h  
8Na}Wp;|Gi  
public int getNSplitter() <:H  
{ "otr+.{`*  
return nSplitter; FkLQBpp(x  
} O{O9}]6  
7Co3P@@  
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public void setNSplitter(int nCount) 
~6=Wq64  
{ %,h!: Ec^c  
nSplitter = nCount; ~p0e=u  
} E%KC'TN^D  
} 1"N/ZKF-x  
30:HRF(:  
6!i( \Q*  
/*
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**Utility.java sT@u3^>  
*/ (gv=P>:  
package NetFox; i]V F'tG  
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public class Utility { w`2_6[,9  
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public Utility() noWRYS%  
{ wK/}E h\^  
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} @D(KuF  
\r)_-  
//线程睡眠 Vu^Q4Z  
public static void sleep(int nSecond) jauc*347  
{ U]1>?,Nk'3  
try{ .oW~:mY  
Thread.sleep(nSecond); ixoMccU0  
} d{(s-  
catch(Exception e) iGpK\oH  
{ (Qw`%B  
e.printStackTrace (); 6T5A31 Q  
} F='jmiVJ  
} CYY X\^hA  
96^1Ivd  
//日志 X}ey0
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public static void log(String sMsg) |~1rKzZwF  
{ U/v"?pg[  
System.err.println(sMsg); e\+~  
} l#<}|b  
rVc zO+E  
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public static void log(int sMsg) N P0Hg
d  
{ ~50y-  
System.err.println(sMsg); ]-+.lR%vd9  
} [7ek;d;'t  
} hA&j?{  
8z3I~yL_`+  
.j]OO/,  
/* 9|?(GG  
**TestMethod.java JXD?a.vy^q  
*/ %^)JaEUC  
package NetFox; xhp-4  
Sj=69>m]5  
K[3D{=  
public class TestMethod { eO[Cb]Dy:  
!D|pbzQc8  
6#lC(ko'  
public TestMethod() 0wa!pE"  
{ ///xx/weblogic60b2_win.exe '"G %0y  
try{ Ke;X3j ]`  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); EY[
Q%  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); `mHOgS>|  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 3Wtv+L7Br  
fileFetch.start();  6@Z'fT4  
} O'yjB$j  
catch(Exception e){e.printStackTrace ();} \w@_(4")Qb  
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=-s20mdj  
} 9OO_Hp#|9  
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:\w[xqH  
public static void main(String[] args)
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{ ~IJZM`gN  
new TestMethod(); %
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} ?U9d3] W  
} XCi]()TZ_  
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