http断点续传简单实现（java)

/* {MSE}|A\V  
**SiteFileFetch.java Z)M "`2Ur  
*/
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package NetFox; 5dI=;L>D  
import java.io.*; o_BTo5]  
import java.net.*; [Hx(a.,d  
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public class SiteFileFetch extends Thread { YE~IO5   
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SiteInfoBean siteInfoBean = null; //文件信息Bean rB$~,q&.V  
long[] nStartPos; //开始位置 rZJJ\ , |  
long[] nEndPos; //结束位置 e,/]]E/o  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ~TEn +  
long nFileLength; //文件长度 .R)P |@z L  
boolean bFirst = true; //是否第一次取文件 m^}|LB:5  
boolean bStop = false; //停止标志 Cl<!S`  
File tmpFile; //文件下载的临时信息 P:4"~]}  
DataOutputStream output; //输出到文件的输出流 M7cD!s@'I  
8qg%>ZU4d  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） C$TU TS  
public SiteFileFetch(SiteInfoBean bean) throws IOException ou<3}g  
{ 
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siteInfoBean = bean; t{jY@JT|  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); y>aO90wJ  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); jJ$B^Y"4  
if(tmpFile.exists ()) t4_
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{ <@KIDZYC  
bFirst = false; J W@6m  
read_nPos(); XNWtX-[^@  
} gZ$ 8Y7  
else Ne1Oz}  
{ 0BlEt1e2T  
nStartPos = new long[bean.getNSplitter()]; rM,e$  
nEndPos = new long[bean.getNSplitter()]; ,s#~00C|  
} &/]en|f"  
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} E=ijt3  
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public void run() I]v2-rB&-  
{ P);s0Y|@H  
//获得文件长度 DJ,LQj  
//分割文件 i *.Y  
//实例FileSplitterFetch z_$c_J  
//启动FileSplitterFetch线程 g2|Myz)  
//等待子线程返回 i
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try{ FtIcA"^N  
if(bFirst) iAu/t  
{ iH }-  
nFileLength = getFileSize(); 7z4k5d<^_  
if(nFileLength == -1) a.Z@Z!*  
{ noxJr/A]  
System.err.println("File Length is not known!"); eut2x7Z(c  
} o:AfEoH"~  
else if(nFileLength == -2) %;k Hnl  
{ `s CwgY+  
System.err.println("File is not access!"); w+R/>a(]  
} 2F:qaz  
else z3+@[I$  
{ .d1ff];  
for(int i=0;i<nStartPos.length;i++) 9;e!r DW,#  
{ k
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); f$xXR$mjf  
} n^4R]9U  
for(int i=0;i<nEndPos.length-1;i++) 2CzhaO  
{ (?|M'gZ  
nEndPos = nStartPos[i+1]; p"ytt|H  
} aV'bI  
nEndPos[nEndPos.length-1] = nFileLength; ;t{q]"? W  
} ?uq`|1`  
} ApCU|*r)  
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//启动子线程 Jp=fLo 9  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 'ZuS  
for(int i=0;i<nStartPos.length;i++) y!#-[K:  
{ M/?,Qii  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), c C3>Ff'  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 5daq}hsQs  
nStartPos,nEndPos,i); @L3XBV2  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); T$%|=
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fileSplitterFetch.start(); y/Xs+ {x  
} al9wNtMT  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Q1,sjLO-a  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); )\akIA  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", l{k_;i!D  
nEndPos = " + nFileLength);  'o-4'  
// fileSplitterFetch[nPos.length-1].start(); ,QcS[9$  
0B`X056|"|  
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//等待子线程结束 5?7AzJl>  
//int count = 0; @j/2 $  
//是否结束while循环 %\m"Yi]  
boolean breakWhile = false; jW'YQrj{<Y  
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while(!bStop) n3a.)tcC  
{ _%nz-I  
write_nPos(); RuPnWx!  
Utility.sleep(500); .Kb3VNgwvm  
breakWhile = true; 4VJUu`[  
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d
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for(int i=0;i<nStartPos.length;i++) ~bLx2=-"  
{ \R#SoOd  
if(!fileSplitterFetch.bDownOver) +=3=%%?C  
{ 6X \g7bg  
breakWhile = false; <Y]LY_(  
break; tk"+ u_uw  
} sK}AS;:  
} Fv$tl)p*  
if(breakWhile) 4ijtx)SA  
break; N''QQBUD  
yKc-:IBb{u  
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//count++; c7e,lgG-  
//if(count>4) @Vm*b@  
// siteStop(); Og\k5.! ,  
} 9bM\ (s/  
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System.err.println("文件下载结束！"); K zWo}tT  
} 'R7 \  
catch(Exception e){e.printStackTrace ();} uz8LF47@:-  
} n#(pT3&  
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JVc{vSa!rm  
//获得文件长度 8SGaS&  
public long getFileSize() 9wvlR6z;u  
{ c[h~=0UtJ  
int nFileLength = -1; 6mM9p)"$  
try{ @5>#<LV=E#  
URL url = new URL(siteInfoBean.getSSiteURL()); cLtVj2Wb  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); U$OZkHA[  
httpConnection.setRequestProperty("User-Agent","NetFox"); 39X~<\&'  
7UfNz60+~  
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int responseCode=httpConnection.getResponseCode(); GK@OdurAR  
if(responseCode>=400) 6r)P&J  
{ ![_x/F9  
processErrorCode(responseCode); >i/jqT/  
return -2; //-2 represent access is error Tq1\  
} kaBjA*  
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String sHeader; n!jmxl$  
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for(int i=1;;i++) oZ'a}kF  
{ N^L@MR-  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 8x{Owj:Q  
//Utility.log(in.readLine()); .biq)Le  
sHeader=httpConnection.getHeaderFieldKey(i); 4#$#x=:  
if(sHeader!=null) ? #K|l*  
{ ]E`<8hRB  
if(sHeader.equals("Content-Length")) Pe,>ny^J1  
{ lTx_E#^s  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); :Jd7q.  
break; 4V+bE$Wu  
} c!6D{(sfh  
} Itl8#LpLM  
else l1+l@r\  
break; nS+Rbhs  
} ?UXFz'  
} ":!$Jnj,  
catch(IOException e){e.printStackTrace ();} :#rP$LSYC  
catch(Exception e){e.printStackTrace ();} -&Rv=q>  
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Utility.log(nFileLength); A}9Z%U  
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return nFileLength; 1NZ"\9=U  
} F y+NJSG  
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>*-%:ub  
//保存下载信息（文件指针位置） GP};~  
private void write_nPos() c./\sN@  
{ VvhfD2*T  
try{ 1Bh"'9-!JT  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ho\1[xS  
output.writeInt(nStartPos.length); fM=o?w6v  
for(int i=0;i<nStartPos.length;i++) Z\!,f.>g  
{ D!j/a!MaKk  
// output.writeLong(nPos); xl}rdnf}  
output.writeLong(fileSplitterFetch.nStartPos);
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output.writeLong(fileSplitterFetch.nEndPos); }k^uup*{  
} p Cz6[*kC  
output.close(); {U5
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} pBsb>wvej  
catch(IOException e){e.printStackTrace ();} dY1t3@E  
catch(Exception e){e.printStackTrace ();} :qzg?\(  
} VPMu)1={:p  
&[E\2 E  
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//读取保存的下载信息（文件指针位置） L}Z.FqJ  
private void read_nPos() *$Q>Om]  
{ iq&3S0  
try{ ipSMmpB  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); +H-=`+,  
int nCount = input.readInt(); Eb3ZM#  
nStartPos = new long[nCount]; LlTD =tJ0  
nEndPos = new long[nCount]; EGu%;[  
for(int i=0;i<nStartPos.length;i++) BA;r%?MRL  
{ M8},RR@{  
nStartPos = input.readLong(); )GP;KUVae  
nEndPos = input.readLong(); T.bFB+'E|  
} J Enjc/  
input.close(); %cF`x_h[j  
} .D*Qu}  
catch(IOException e){e.printStackTrace ();} -^p{J TB+  
catch(Exception e){e.printStackTrace ();} DE(XSzX  
} *!5CL'  
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private void processErrorCode(int nErrorCode) vhe Y F@  
{ 
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System.err.println("Error Code : " + nErrorCode); |x}TpM;ni  
} 1XGg0SC  
)GB#"2  
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//停止文件下载 oo'9ZE/%  
public void siteStop() = 0 ~4k#  
{ )nN!% |J  
bStop = true; -#\T  
for(int i=0;i<nStartPos.length;i++) 1/dL-"*0  
fileSplitterFetch.splitterStop(); ~ #jQFyOh  
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} 8hGyh#  
} y_X6{}Ke  
//负责部分文件的抓取 oz!)x\m*H  
**FileSplitterFetch.java `z!AjAT-G  
*/ z'L0YqXG/  
package NetFox; ~Ntk-p  
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*C*J1JYp+  
import java.io.*; g/GI'8EMj  
import java.net.*; y0%@^^-Ru  
} z'Jsy[s  
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public class FileSplitterFetch extends Thread { (5T>`7g8  
2?,Jn&i5  
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String sURL; //File URL (HNc9QVC'W  
long nStartPos; //File Snippet Start Position Mc,79Ix"  
long nEndPos; //File Snippet End Position ,np=m17  
int nThreadID; //Thread's ID 2Kxb(q"  
boolean bDownOver = false; //Downing is over v93b8/1  
boolean bStop = false; //Stop identical {&1L &f<  
FileAccessI fileAccessI = null; //File Access interface cy%M$O|hX5  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 6h9(u7(-N  
{ ]E9iaq6Z  
this.sURL = sURL; |MNSIb&,W  
this.nStartPos = nStart; rto?*^N?  
this.nEndPos = nEnd; HUKrp*Hv  
nThreadID = id; EX)&|2w  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Ez1eGPVr  
} 9<mMU:  
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public void run() *HrEh;3^J  
{ }*x1e_m}H  
while(nStartPos < nEndPos && !bStop) B
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{ N*gJu  
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try{ "L>'X22ed  
URL url = new URL(sURL); N{Sp-J>  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); @IG's-  
httpConnection.setRequestProperty("User-Agent","NetFox"); !)a_@d.;i  
String sProperty = "bytes="+nStartPos+"-";
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httpConnection.setRequestProperty("RANGE",sProperty); Du_5iuMh  
Utility.log(sProperty); ay8]"sa  
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InputStream input = httpConnection.getInputStream(); \M`qaFan5^  
//logResponseHead(httpConnection); +wi=IrRr  
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byte[] b = new byte[1024]; CE"/&I  
int nRead; .s{"NqRA  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) x`6MAZ  
{ s&73g0$$  
nStartPos += fileAccessI.write(b,0,nRead); (~~m8VJ>  
//if(nThreadID == 1) w:\} B'u  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); !5,C"r  
} ~RR!~q  
(T1< (YZ  
&2ED<%hH`  
Utility.log("Thread " + nThreadID + " is over!"); Jv}  
bDownOver = true; {!Qu(%  
//nPos = fileAccessI.write (b,0,nRead); ^4sfVpD2!  
} fD!c t;UK  
catch(Exception e){e.printStackTrace ();} p%I)&- 8  
} N[Z`tk?-  
} &d6@SQ  
=-sT
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//打印回应的头信息 jE0oLEg&  
public void logResponseHead(HttpURLConnection con) ^I
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{ j\C6k  
for(int i=1;;i++) $>)0t@[f  
{ 7. F'1oEf  
String header=con.getHeaderFieldKey(i); [CQR  
if(header!=null) /A9RmTb  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 8lQ}-8  
Utility.log(header+" : "+con.getHeaderField(header)); 5kHaZ Q  
else 217G[YE-  
break; =j>xu|q  
} x80IS:TP  
} %+*=Vr  
VR
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public void splitterStop() 5RPG3ppS  
{ 0F[f%2j  
bStop = true; #xtH6\X  
} xmg3,bO  
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} .n<vhLDQn  
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/* s#?ZwD,=  
**FileAccess.java sK2N3B&6  
*//文件访问(定位，写) -6[DQB  
package NetFox; v,<14w  
import java.io.*; {/QVs?d  
<-I69`  
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public class FileAccessI implements Serializable{ c~<;}ve^z  
J&8KIOz14Z  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 -,8LL@_  
RandomAccessFile oSavedFile; 5`^@k<  
long nPos; f|{iW E2d  
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public FileAccessI() throws IOException 7 $y;-[
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{ 4en3yA0.w  
this("",0); Gxw1P@<F:  
} =RB {.%  
n&
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public FileAccessI(String sName,long nPos) throws IOException Fi``l)Tt  
{ xF8r+{_J)  
oSavedFile = new RandomAccessFile(sName,"rw"); &M13F>!  
this.nPos = nPos; V\`Z|'WIQD  
oSavedFile.seek(nPos); GLsa]}m,9  
} 3E*
|^*  
(=j;rfvP  
b~aM=71  
public synchronized int write(byte[] b,int nStart,int nLen) ](Fey0@  
{ /DAR'9@h  
int n = -1; ,@ '^3u  
try{ G*9(O:  
oSavedFile.write(b,nStart,nLen); ABCm2$<  
n = nLen; Yg&(kmm  
} ?X@!jB,Pv  
catch(IOException e) G80N8Lm  
{ GRcPzneiz  
e.printStackTrace (); >pF*unC;  
} zj7ta[<tr  
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return n; i.mv`u Dm  
} M@ U>@x;  
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} %#2$B+  
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/* W %*#rcdq  
**SiteInfoBean.java O,r;-t4vYU  
*/ p!pf2}6Fd  
package NetFox; X
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public class SiteInfoBean { +4 k=Y  
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private String sSiteURL; //Site's URL rI>x'0Go*  
private String sFilePath; //Saved File's Path
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private String sFileName; //Saved File's Name c{=;lT  
private int nSplitter; //Count of Splited Downloading File -`faXFW'  
9L>?N:%5  
COw"6czX/  
public SiteInfoBean() T8+[R2_  
{//nSplitter的缺省值为5 (4FVemgy  
//default value of nSplitter is 5 PK+sGV  
this("","","",5); ${T/b(NM  
} @;egnXxF<  
=gj?!d`  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) IAO5li3  
{ 5_(\Cd<#  
sSiteURL= sURL; `vBBJ@f4)  
sFilePath = sPath; Wj.t4XG!  
sFileName = sName; Lap?L/NS  
this.nSplitter = nSpiltter; %Y&48''"  
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j!4{+&Laq  
} X /c8XLe"  
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public String getSSiteURL() "W(D0oy  
{ d]0:r]e  
return sSiteURL; w;,34qbf  
} T?RY~GA  
m}l);P^  
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public void setSSiteURL(String value) GlJ[rD  
{ ^("b~-cJ  
sSiteURL = value; &@lfr623  
} e* [wF}))  
w-Ph-L/  
xeF>"6\  
public String getSFilePath() Zv@qdY<:  
{ `PARZ|  
return sFilePath; xUn"XkhP  
} 9Jwd*gevV  
Z:{| ?4  
&. =8Q?  
public void setSFilePath(String value) X,49(-~\  
{ 5|rBb[  
sFilePath = value; cM%?Ot,mK"  
} ]he~KO[j<  
HR-'8?)R.A  
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public String getSFileName() /NQrE#pb  
{ We y*\@  
return sFileName; RsDSsux  
} ,NGHv?.N  
#zP-,2!r  
@V 'HX  
public void setSFileName(String value) $+80V{J#  
{ 7{<v$g$  
sFileName = value; 0)|Z7c&  
} H8YwMhE7  
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public int getNSplitter() 6) i-S<(  
{ K9@.l~n  
return nSplitter; li[[AAWVm  
} p<
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6)1PDlB  
public void setNSplitter(int nCount) `dm*vd  
{ &>AwG4HW#j  
nSplitter = nCount; My>q%lF=fw  
} bpc1>?  
} 8oE`>Y  
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/* ~Z5AImR|  
**Utility.java Bv7FZK3  
*/ bo#xqSGQ  
package NetFox; ir6aV|ea!  
?q`i MiN  
a6gw6jQ  
public class Utility { N5K(yY_T  
-L/%2 X  
N)mZ!K44  
public Utility() ?pIELezfK  
{ L,R}l0kc  
6 ZRc|ZQ  
\~8W0q.4M  
} 8(Az/@=n  
~g!!#ad  
//线程睡眠 p*PzfSLN  
public static void sleep(int nSecond) N~]qQoj,  
{ +Kgl/Wg%  
try{ 62ru%<x=  
Thread.sleep(nSecond); IN/$b^Um  
} 4Wgzp51Aq!  
catch(Exception e) 9"^ib9M  
{ z*T41;b  
e.printStackTrace (); #U-y<[ 3  
} "&H'?N%9Up  
} A_TaXl(  
-G>J  
//日志 oO;L l?~  
public static void log(String sMsg) 3!9JXq%Hl  
{ M_!]9#:K7  
System.err.println(sMsg); d21thV ,S  
} 2D%2k  
`]65&hWZL  
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public static void log(int sMsg) Y[e.1\d'  
{ 5 Y&`ZJ  
System.err.println(sMsg); \SmsS^z(]  
} WT\wV\Pu  
} mW]dhY 3X  
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/* O^\:J2I(  
**TestMethod.java <N<0?GQ  
*/ W!HjO;  
package NetFox; (ORbhjl  
EPW4
h/I  
hRXnig{;3  
public class TestMethod { Vsi:O7|+ }  
u)h {"pP  
@MibKj>o  
public TestMethod() _v#puFy  
{ ///xx/weblogic60b2_win.exe egsP\ '  
try{ &PXT$x[i  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); {*bx8*y1  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); UA'bE
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SiteFileFetch fileFetch = new SiteFileFetch(bean); o`,}b1lh  
fileFetch.start(); *i*\dl  
} ^n
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catch(Exception e){e.printStackTrace ();} r3x;lICx-  
]+`K\G ^X  
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} V^tD@N  
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public static void main(String[] args) )-X8RRw'  
{ _886>^b@  
new TestMethod(); RCfeIHL  
} >A{e,&  
} Z?S?O#FED  
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