http断点续传简单实现（java)

/* \E<Qi3W>*  
**SiteFileFetch.java w6)Q5H53)  
*/ 
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package NetFox; VB#&`]rdo  
import java.io.*; R! On  
import java.net.*; EP>Lh7E9n  
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public class SiteFileFetch extends Thread { <\O8D0.d  
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SiteInfoBean siteInfoBean = null; //文件信息Bean EhM=wfGKw  
long[] nStartPos; //开始位置 bgKC^Q/F  
long[] nEndPos; //结束位置 FI.F6d)E$  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 -!\%##r7~  
long nFileLength; //文件长度 P=KhR&gwV~  
boolean bFirst = true; //是否第一次取文件 ,aGIq. *v  
boolean bStop = false; //停止标志 *78c2`)[  
File tmpFile; //文件下载的临时信息 m-ibS:  
DataOutputStream output; //输出到文件的输出流 }^$1<GT  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） #+V4<o  
public SiteFileFetch(SiteInfoBean bean) throws IOException cL~WDW/  
{ a$Y{ut0t(  
siteInfoBean = bean; T*PEUq  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); dcD#!v\0  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); &rD8ng+$  
if(tmpFile.exists ()) D4|Ajeo;1  
{ [ }Tb2|  
bFirst = false; r@q
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read_nPos(); 9_iwikD  
} PnInsf%;  
else q5=,\S3=  
{ ]1Wxa?  
nStartPos = new long[bean.getNSplitter()]; zrG  
nEndPos = new long[bean.getNSplitter()]; VPuR4p.  
} CfP-oFHoQ  
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%.r\P@7/Q  
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} A%HIfSzQBS  
/|P{t{^WM  
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public void run() 6kLy!QS  
{ l9="ccM  
//获得文件长度 *A
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//分割文件 :[328X2  
//实例FileSplitterFetch ".$kOH_:  
//启动FileSplitterFetch线程 'j, 
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//等待子线程返回 fpf,gb8[$n  
try{ :Dw_$  
if(bFirst) LjE3|+pJ  
{ WysWg7,r  
nFileLength = getFileSize(); &Tuj`DL  
if(nFileLength == -1) zhd1)lgY  
{ xH{-UQ3R  
System.err.println("File Length is not known!"); '@ Y@Fs  
} 9T5 F0?qd  
else if(nFileLength == -2) rTR"\u7&H  
{ KCw  
System.err.println("File is not access!"); *AW v  
} fW+"Kuw  
else {d;z3AB  
{ IF|;;*Z8  
for(int i=0;i<nStartPos.length;i++) 3en67l  
{ l5Ko9CG  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); aF+Lam(  
} y*{zX=]l<  
for(int i=0;i<nEndPos.length-1;i++) gN:F50  
{ M'<% d[  
nEndPos = nStartPos[i+1]; zEtsMU  
} =<p=?16 x  
nEndPos[nEndPos.length-1] = nFileLength; tlUh8os  
} 7<MEMNYX  
} d94k  
D:bmq93PC  
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//启动子线程 O!f37n-TB  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 4c 8{AZ  
for(int i=0;i<nStartPos.length;i++) l1'v`!  
{ k)*apc\W  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), =Q<7
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), + c3pe4  
nStartPos,nEndPos,i); *->*p35  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); mHW%:a\L  
fileSplitterFetch.start(); Gt*K:KT=L  
} 0Atha>w^o~  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), h+j^VsP zB  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); z{\tn.67  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", `14@dk  
nEndPos = " + nFileLength); }BI6dZ~2A  
// fileSplitterFetch[nPos.length-1].start(); m!w|~Rk  
' *a}*(0OA  
W-#DEU 7_  
//等待子线程结束 wzju)qS  
//int count = 0; .#SgU<Wq  
//是否结束while循环 1~K'r&  
boolean breakWhile = false; Bt}90#  
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~ E6e~  
while(!bStop) y.D+M$f  
{ gs3(B/";c  
write_nPos(); =KOi#;1  
Utility.sleep(500); hIV]ZYbH  
breakWhile = true; 6JZ>&HA  
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v9*+@  
for(int i=0;i<nStartPos.length;i++) 8CUtY9.  
{ Gkem_Z  
if(!fileSplitterFetch.bDownOver) T%6JVFD  
{ /tj]^QspS  
breakWhile = false; ]goJ- &  
break; a<\n$E#q  
} D|)_c1g  
} |rk.t g9  
if(breakWhile) 06%-tAq:  
break; \UZGXk  
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//count++; N6-7RoA+  
//if(count>4) '=Zm[P,  
// siteStop(); ?<3 d Fb  
} 9AhA"+?  
m=@xZw<  
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System.err.println("文件下载结束！"); r1-MO`6  
} 6}I X{nQI  
catch(Exception e){e.printStackTrace ();} \)t//0  
} d;l%XZe  
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&-Ch>:[  
//获得文件长度 J(d+EjC  
public long getFileSize() ^;a .;wR  
{ E7\K{]  
int nFileLength = -1; 3WQa^'u  
try{ uGC5XX^  
URL url = new URL(siteInfoBean.getSSiteURL()); .uauSx/#4  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); TCRTC0_}k  
httpConnection.setRequestProperty("User-Agent","NetFox"); V;MmPNP|  
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int responseCode=httpConnection.getResponseCode(); B<r0y  
if(responseCode>=400) |X:`o;Uma  
{ uXFI7vV6P  
processErrorCode(responseCode); .W~XX  
return -2; //-2 represent access is error K |=o-  
} z*jaA;#  
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)u{]rb[  
String sHeader; |=YK2};  
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for(int i=1;;i++) PVlCj  
{ o5&b'WUJ=  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); K1J |\!
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//Utility.log(in.readLine()); <lIm==U<-  
sHeader=httpConnection.getHeaderFieldKey(i); _xh)]R  
if(sHeader!=null) t{iRCj  
{ k-n`R)p:  
if(sHeader.equals("Content-Length")) K% FK  
{ ,v})  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); =Mwuhk|*  
break; q:)PfP+  
} KZ[TW,Gw  
} |s/N?/qi  
else Nkj$6(N=zJ  
break; U"8Hw@  
} #2%V  
} E3j`e>Yz  
catch(IOException e){e.printStackTrace ();} ?sdSi--  
catch(Exception e){e.printStackTrace ();} tDL.+6/  
fK=0?]s}I  
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Utility.log(nFileLength); :tO4LEb  
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return nFileLength; ?:`sE"  
} ps2j]g  
bR"4:b>K  
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//保存下载信息（文件指针位置） a_}C*+D  
private void write_nPos() \K\eq>@6  
{ "t
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try{ f4.jWBF  
output = new DataOutputStream(new FileOutputStream(tmpFile)); "$(D7yFO  
output.writeInt(nStartPos.length); tL;.vR
x  
for(int i=0;i<nStartPos.length;i++) pJ8F
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{ v]on0Pi!  
// output.writeLong(nPos); .-HM{6
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output.writeLong(fileSplitterFetch.nStartPos); };rp25i  
output.writeLong(fileSplitterFetch.nEndPos); )tJaw#Mih  
} !Ltx2CB2]  
output.close(); )=}qAVO8  
} &aIFtlC  
catch(IOException e){e.printStackTrace ();} }G{"Mp4  
catch(Exception e){e.printStackTrace ();} `)8~/G%  
} _GxC|d  
w=_^n]`R  
{'+{ASpO!  
//读取保存的下载信息（文件指针位置） `+< ^Svou  
private void read_nPos() >2>/ q?  
{ {,Vvm*L/  
try{ q%d'pF  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ?m~1b_@A{  
int nCount = input.readInt(); 9>-6Y  
nStartPos = new long[nCount]; u `xQC/  
nEndPos = new long[nCount]; g$e|y#Ic$  
for(int i=0;i<nStartPos.length;i++) Cx~;oWZ  
{ 9a=:e=q3#  
nStartPos = input.readLong(); 7WSP0Xyz  
nEndPos = input.readLong(); C=oeRc'r1W  
} AlDp+"|  
input.close(); L"9Z{o
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} ef7 U7  
catch(IOException e){e.printStackTrace ();} "aKlvK:77  
catch(Exception e){e.printStackTrace ();} >CrrxiG  
} +2:HgW  
. U6(>6-  
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private void processErrorCode(int nErrorCode) 2 ^"j]g>mj  
{ H0OO+MCe  
System.err.println("Error Code : " + nErrorCode); 1ED7
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} IfB .2e`  
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hC"'cUrcN  
//停止文件下载 bR~Xog  
public void siteStop() TDk[,4  
{ HFjSM~  
bStop = true; 8*b{8%<K  
for(int i=0;i<nStartPos.length;i++) T&/n.-@nk  
fileSplitterFetch.splitterStop(); cz/E  
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} khR[8j..  
} .53 M!  
//负责部分文件的抓取 )P9]/y  
**FileSplitterFetch.java 4=^Ha%l  
*/ bnL!PsG$K,  
package NetFox; 4|%Y09"lv  
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import java.io.*; 9xJtDdy-O  
import java.net.*; 1l)j(,Zd*  
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public class FileSplitterFetch extends Thread { PhuHfw4$y,  
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String sURL; //File URL a(yWIgD\\  
long nStartPos; //File Snippet Start Position o`QH8  
long nEndPos; //File Snippet End Position \6 JY#%  
int nThreadID; //Thread's ID <tZtt9j_  
boolean bDownOver = false; //Downing is over 5#|
&&$)  
boolean bStop = false; //Stop identical C=Fu1H
pb  
FileAccessI fileAccessI = null; //File Access interface .,'4&}N}  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException <%wTI<m,-  
{ U9PI#TX &O  
this.sURL = sURL; uAnL`
 
this.nStartPos = nStart; W!" $g  
this.nEndPos = nEnd; v~AshmP  
nThreadID = id; ;,]4A{|  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 k9H}nP$F  
} rIB./,  
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public void run() J3oU
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{ Ux^ue9  
while(nStartPos < nEndPos && !bStop) {I0!q"sF  
{ &x*l{s[  
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#+Bz$CO  
try{ _?felxG[  
URL url = new URL(sURL); %LHt{:9.  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ,@p4HN*  
httpConnection.setRequestProperty("User-Agent","NetFox"); .1^Kk3  
String sProperty = "bytes="+nStartPos+"-"; R(_WTs9x4  
httpConnection.setRequestProperty("RANGE",sProperty); +Q5'!@8  
Utility.log(sProperty); $Sy}im
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9k62_]w@6  
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InputStream input = httpConnection.getInputStream(); IY!.j5q8  
//logResponseHead(httpConnection); >2K'!@~'  
3zfpFgD!  
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byte[] b = new byte[1024]; )D+eWo  
int nRead; =s:kC`O  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) m7A3i<6p  
{ \N|}V.r  
nStartPos += fileAccessI.write(b,0,nRead); hB>FJZQ_  
//if(nThreadID == 1) e 5(|9*t  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); )~$ejS  
} z\, lPwB2  
! B`  
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Utility.log("Thread " + nThreadID + " is over!"); hqHk,#  
bDownOver = true; uj%]+Llxv  
//nPos = fileAccessI.write (b,0,nRead); KDP&I J  
} Y*lc ~X  
catch(Exception e){e.printStackTrace ();}  %>zG;4  
} &l`_D?{<#  
}
:ba4E[@  
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//打印回应的头信息 lxD~l#)^ln  
public void logResponseHead(HttpURLConnection con) _E0yzkS  
{ 2C"i2/NH'  
for(int i=1;;i++) SMB&sl  
{  0RCp  
String header=con.getHeaderFieldKey(i); *<{hLf  
if(header!=null) &Nr+-$  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 1p/_U?H:|  
Utility.log(header+" : "+con.getHeaderField(header)); %,S:^Rvv  
else
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break; F!I9)PSj  
} :*l\j"fX5  
} N7 _
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&C9)%5O)  
. Z9c.E{  
public void splitterStop() $i3`cX)g  
{ bFA lC  
bStop = true; y~t e!C  
} "f3mi[  
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} u XZ;K.  
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/* h6`VU`pPI  
**FileAccess.java \Yv44*I`  
*//文件访问(定位，写) md9JvbB  
package NetFox; 4/SltWU  
import java.io.*; E.*wNah"U  
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,(hP /<  
public class FileAccessI implements Serializable{ #~|esr/wf  
Mac:E__G  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 `09[25?  
RandomAccessFile oSavedFile; eXLdb-  
long nPos; xo-}t5w6t  
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=zp{ ^mC  
public FileAccessI() throws IOException "x:-#2+h  
{ oq>jCOVh  
this("",0); eq2LV=d{m  
} .o<9[d"  
p[!9objU  
4q@[k:'  
public FileAccessI(String sName,long nPos) throws IOException I.2>d_^<  
{ 8y?q)y9h  
oSavedFile = new RandomAccessFile(sName,"rw"); S@,x^/vT  
this.nPos = nPos; -s91/|n  
oSavedFile.seek(nPos); Ym-mfWo^#  
} 5!6iAS+I  
_|{pO7x]oG  
!D 'A  
public synchronized int write(byte[] b,int nStart,int nLen) S->S
p  
{ 5VN~?#K  
int n = -1; NfCo)C-t  
try{ O]25{L  
oSavedFile.write(b,nStart,nLen); I|/|\  
n = nLen; ]jmZ5h#[  
} ,mD$h?g  
catch(IOException e) PDh!B_+  
{ 2:[G4  
e.printStackTrace (); Sc]h^B^7  
} @Js@\)P79  
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return n; iNn?G C>  
} J,`I>^G  
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} xaIe7.Z"xo  
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/* T(kG"dz   
**SiteInfoBean.java p|)j{nc  
*/ gF~ }  
package NetFox; 0}Qd  
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public class SiteInfoBean { 'EU|w,GL}  
8PRB_ny  
5XNFu C9E  
private String sSiteURL; //Site's URL DCCijN  
private String sFilePath; //Saved File's Path s*kSl:T@O  
private String sFileName; //Saved File's Name aQ1n1OBr  
private int nSplitter; //Count of Splited Downloading File \AD|;tA\vE  
(rf8"T!"  
<$nMqUu0  
public SiteInfoBean() Wb{8WPS  
{//nSplitter的缺省值为5 **n109R  
//default value of nSplitter is 5 Q>/[*(.Wd  
this("","","",5); %BkPkQA  
} C9`x"$  
s:sk`~2<gd  
).r04)/  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) g$Nsu:L  
{ ;q2e[y  
sSiteURL= sURL; z-kB!~r  
sFilePath = sPath; !wjD6NK  
sFileName = sName; 8qq'q"g  
this.nSplitter = nSpiltter; GYri\<[  
xC$CRzAe5p  
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} *C^`+*}OE$  
k/%n7 ;1  
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public String getSSiteURL() s|Zv>Qt  
{ /}-LaiS  
return sSiteURL; !ma'*X  
} ]~m2#g%  
-$j|&l  
'A#l$pJp7  
public void setSSiteURL(String value) |+Ub3<b[]  
{ #xxs^Kbqa#  
sSiteURL = value; gG46hO-M%x  
} y/Q,[Uzk\  
+q~dS.  
-Wl79lE  
public String getSFilePath() 4ko(bW#jL  
{ -(![xZ1{K  
return sFilePath; kM@heFJb.  
} ^WIGd"^  
JVNp= ikK  
B#x.4~YX  
public void setSFilePath(String value) gA DF  
{ " [K>faV  
sFilePath = value; Hz3KoO &  
} *8xMe  
1"} u51  
8|\?imOp\[  
public String getSFileName() t9m08K:Y  
{ H5p&dNO  
return sFileName; g=n /w  
} =xsTVT;sj  
8u#2M8.5E  

[
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public void setSFileName(String value) THDyb9_g  
{ dht*1i3v  
sFileName = value; g%f6D%d)A  
} ioS(;2F  
RE75TqYW  
[>U =P`  
public int getNSplitter() NYp46;  
{ 3n=ftkI  
return nSplitter; .uu[MzMIu  
} XSz)$9~hk  
~i/K7qZ  
.Zv uhOn^  
public void setNSplitter(int nCount) Q96^rjY  
{ iwT PJGK|  
nSplitter = nCount; ;R{ffS6  
} "iTi+UZxe  
} jr=erVHK  
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@t?uhT*Z=  
/* Eh&HN-&  
**Utility.java 
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*/ I Z{DR  
package NetFox; l^E)XWd  
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public class Utility { .=<
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M[7$cfp-Y~  
public Utility() _mn2bc9M  
{ ORP-@-dap  
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} MF/@Efjn ]  
tEHgQto  
//线程睡眠 ae|j#!~oi  
public static void sleep(int nSecond) K/ 5U;oC  
{ 1=Nh<FuQ  
try{ ct![eWsuB  
Thread.sleep(nSecond); ~zT743  
} R\d)kcy4  
catch(Exception e) sW]fPa(cn,  
{ aJ^RY5  
e.printStackTrace (); ]KE"|}B  
} B(h%>mT[  
} TdWatvY5p  
.7|Iausv  
//日志 %uy5la  
public static void log(String sMsg) 24Uvi:B?~  
{ 5|0}   
System.err.println(sMsg); UCVdR<<Z  
} ==)q{e5  
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public static void log(int sMsg) >
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{ r`GA5}M  
System.err.println(sMsg); 5isqBu  
} ?,0 a#lG  
} *$yU|,  
cHjnuL0fsy  
@U
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/* ;fGh]i  
**TestMethod.java '$\O*e'  
*/ {f:%+h  
package NetFox; WYXh1_nyk  
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public class TestMethod { ^'ac|+  
e'0BP,\f_}  
|Pj]sh[^Y  
public TestMethod() c$#7Kp4  
{ ///xx/weblogic60b2_win.exe y0_z_S#gO  
try{ ,Vr-E  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); h"$)[k~  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 9qvKg`YSh  
SiteFileFetch fileFetch = new SiteFileFetch(bean); r:-,qy  
fileFetch.start(); %"CF-K@th  
} Hx#1TqC/  
catch(Exception e){e.printStackTrace ();} yHYK,3/C,  
,,HoD~]rd  
&-zW1wf  
} L| K8  
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&ku.Q3xGs  
public static void main(String[] args) +nU=)x?38  
{ S}/5W  
new TestMethod(); &.1qixXIr  
} N/6!|F  
} ^Cy=L]  
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