http断点续传简单实现（java)

/* Y/]J0D  
**SiteFileFetch.java I/_,24[  
*/ F0KNkL>&g  
package NetFox; (V<pz
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import java.io.*; @r]1;KG  
import java.net.*; 1xjw=  
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public class SiteFileFetch extends Thread { f"Kl?IN8  
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SiteInfoBean siteInfoBean = null; //文件信息Bean %9b TfX"  
long[] nStartPos; //开始位置
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long[] nEndPos; //结束位置 paZcTC  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 .6A{   
long nFileLength; //文件长度 suE#'0K  
boolean bFirst = true; //是否第一次取文件 g?{7DI`  
boolean bStop = false; //停止标志 M9QxF  
File tmpFile; //文件下载的临时信息 3\j3vcuy  
DataOutputStream output; //输出到文件的输出流 '@f#GNRT  
l 9bg  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） PBb'`PV  
public SiteFileFetch(SiteInfoBean bean) throws IOException \OVw  
{ [E;~Y_l  
siteInfoBean = bean; ;Swj`'7  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Voo_ ?  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); N{?Qkkgx  
if(tmpFile.exists ()) wpa^]l  
{ VWW(=j  
bFirst = false; u"-."_  
read_nPos(); ,B$e'KQ  
} 1i}p?sU  
else (|sqN8SbA  
{ V"5LNtf  
nStartPos = new long[bean.getNSplitter()]; &Vbcwv@  
nEndPos = new long[bean.getNSplitter()]; &24>9  
} ~' q&rvk`  
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c  
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} F32U;fp3  
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public void run() gsVm)mkd  
{ oB%j3aAH  
//获得文件长度 M7c53fz  
//分割文件 `g'z6~c7n  
//实例FileSplitterFetch 5Eu`1f?  
//启动FileSplitterFetch线程  EHda  
//等待子线程返回 seA=7c5E  
try{ /OeOL3Y  
if(bFirst) :s#&nY  
{ YQaL)t$0  
nFileLength = getFileSize(); %kL]-Z  
if(nFileLength == -1) \= Wrh3  
{ w C-x'  
System.err.println("File Length is not known!"); T^H`$;\  
} c1h?aP  
else if(nFileLength == -2) Z(hRwIOF  
{ fX}dQN~z  
System.err.println("File is not access!"); !==C@cH<N  
} zqm/<]A*l  
else ;c|G  
{ .2/W.z2  
for(int i=0;i<nStartPos.length;i++) <v$yXA  
{ :2-!bLo}&  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); M][Zu[\*  
} GL3olKnL  
for(int i=0;i<nEndPos.length-1;i++) ..yLtqos  
{ T9]:, z  
nEndPos = nStartPos[i+1]; jo ~p#l.'  
} 7jYW3  
nEndPos[nEndPos.length-1] = nFileLength; :+UahwiRD"  
} Q*]y=Za#:  
} <%=@Ue  
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H)NT2@%{P  
//启动子线程 Rs53R$PIR  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; CxJH)H$  
for(int i=0;i<nStartPos.length;i++) v Yw$m#@  
{ #&&  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Kr74|W=  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), rB.LG'GG]  
nStartPos,nEndPos,i); W(jP??up  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ])mYE }g  
fileSplitterFetch.start(); e*pYlm  
} RhI>Ak;-  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ){"-J&@?  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); |"k+j_/+  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 8&++S> <  
nEndPos = " + nFileLength); we2D!Ywr  
// fileSplitterFetch[nPos.length-1].start(); c8M'/{4rH  
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 ui1h M  
//等待子线程结束 R%)7z)~  
//int count = 0; R2dCp|6A  
//是否结束while循环 -+&sPrQ  
boolean breakWhile = false; |H4f&&Wd  
);*#s~R  
P: )YKro]  
while(!bStop) 3L-}B#tI  
{ P{o//M  
write_nPos(); 7A4_b8  
Utility.sleep(500); K5:>  
breakWhile = true; .u&GbM%Ga  
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for(int i=0;i<nStartPos.length;i++) LABLT;c  
{ yn KgNi  
if(!fileSplitterFetch.bDownOver) (
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{ wQ~F%rQ$  
breakWhile = false; ec"+Il  
break; QHbjZJ N  
} AOR(1Qyo  
} p$zj2W+sN  
if(breakWhile) p^9u8T4l1  
break; o 9{~F`{p  
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ql%]t~HR0  
//count++; 'A#F< x  
//if(count>4) _U`1BmTC2  
// siteStop(); UeN+}`!l  
} <#No t1R  
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System.err.println("文件下载结束！"); 7Un5Y[FZo  
} ;8> TD&]{  
catch(Exception e){e.printStackTrace ();} "CF{Mu|Q
=  
} S_Ug=8r4  
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//获得文件长度 F}{uY(hv"[  
public long getFileSize() 8@d,TjJDo  
{ /Q2{w>^DK  
int nFileLength = -1; H<bB@(i  
try{ f)%8*B  
URL url = new URL(siteInfoBean.getSSiteURL()); _Sn7z?  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); br_D Orq|  
httpConnection.setRequestProperty("User-Agent","NetFox"); G5'HrV  
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int responseCode=httpConnection.getResponseCode(); 5_= HtM[v]  
if(responseCode>=400) E>3(ff&  
{ A]q"+Z]  
processErrorCode(responseCode); 2]/[  
return -2; //-2 represent access is error !i*bb
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} PxiJ R[a  
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String sHeader; ?(P3ZTk?.  
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for(int i=1;;i++) j SXVLyz  
{ y%=t((.Z  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Cz]NSG5  
//Utility.log(in.readLine()); )%=oJ!)  
sHeader=httpConnection.getHeaderFieldKey(i); >r
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if(sHeader!=null) gQ~X;'  
{ :;u?TFCRx  
if(sHeader.equals("Content-Length")) 89X`U)W
s  
{ "L~qsFL  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); sQ>L3F;A`  
break; '}.Z' %;  
} .iXIoka  
} *mTx0sQz(J  
else [ #1<W`95  
break; Jx_BjkF  
} N)b.$aC  
} 2#?qey  
catch(IOException e){e.printStackTrace ();} |ZuS"'3_w  
catch(Exception e){e.printStackTrace ();} ^i!6q9<{e  
"~^#{q  
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Utility.log(nFileLength); tsvh/)V  
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return nFileLength; K,Z_lP_~Vw  
} N56/\1R  
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|H7f@b]Sk  
//保存下载信息（文件指针位置） uDXRw*rTv  
private void write_nPos() y o |"-  
{ ^CWxYDG*  
try{ XlGDv*d:#d  
output = new DataOutputStream(new FileOutputStream(tmpFile)); K:\db'``  
output.writeInt(nStartPos.length); (np60mX<  
for(int i=0;i<nStartPos.length;i++) cczV}m2)  
{ z c7P2@  
// output.writeLong(nPos); !HPye@Ua  
output.writeLong(fileSplitterFetch.nStartPos); ,/bv3pE  
output.writeLong(fileSplitterFetch.nEndPos); F2#s^4Ii  
} >
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output.close(); _BP!{~&;  
} #)hJ.0~3  
catch(IOException e){e.printStackTrace ();} Bp>Z?"hTe  
catch(Exception e){e.printStackTrace ();} (viGL|Ogn  
} bw& U[|A0%  
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//读取保存的下载信息（文件指针位置） D?:AHj%gW  
private void read_nPos() lZ![?t}2`  
{ c.;}e:)s  
try{ wz{]CQ7"  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); fce~a\y0  
int nCount = input.readInt(); r[}5<S Q  
nStartPos = new long[nCount]; ,8^QV3  
nEndPos = new long[nCount]; ym~  
for(int i=0;i<nStartPos.length;i++) o+j~~P  
{ <+\ w.!  
nStartPos = input.readLong(); M!j: 2dT"  
nEndPos = input.readLong(); B(TE?[ #  
} #2qDn^s  
input.close(); ,q|;`?R;  
} CV )v6f  
catch(IOException e){e.printStackTrace ();} SZ'2/#R>  
catch(Exception e){e.printStackTrace ();} [@LA<Z_
 
} U3UDA  
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private void processErrorCode(int nErrorCode) 8M&q  
{ OPtFz6  
System.err.println("Error Code : " + nErrorCode); gcKXda(  
} >.X& v  
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!:<(p  
//停止文件下载 $63_*9  
public void siteStop() aUTXg60l*  
{ ta'{S=^j  
bStop = true; 'W2B**}  
for(int i=0;i<nStartPos.length;i++) ?7]UbtW[  
fileSplitterFetch.splitterStop(); =Mby;wQ?|  
;Or]x?-  
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} nhZ^`mP  
} ,6iXlch  
//负责部分文件的抓取 Je1'0h9d  
**FileSplitterFetch.java f%2>pQTq@)  
*/ C@#KZ`c)  
package NetFox; N!#0O.6  
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import java.io.*; Y_SB3 $])  
import java.net.*; }Jr!aM'  
v:7_ZD6kR  
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public class FileSplitterFetch extends Thread { (SnrYO`#  
]8;2Oh   
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String sURL; //File URL x$@Gp  
long nStartPos; //File Snippet Start Position ys~oJb~  
long nEndPos; //File Snippet End Position ZFH;  
int nThreadID; //Thread's ID :*6#(MX  
boolean bDownOver = false; //Downing is over ,u&K(Z%  
boolean bStop = false; //Stop identical |Y")$pjz  
FileAccessI fileAccessI = null; //File Access interface "gCqb;^  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 9-( \\$%  
{ BdQ/kXZu+  
this.sURL = sURL; }
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this.nStartPos = nStart; ]aN]Ha  
this.nEndPos = nEnd; ~(~ y=M  
nThreadID = id; WPpS?  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Fk*C8  
} cq#=Vb  
&]_2tN=S$  
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public void run() I #8TY/XP  
{ ?[z@R4at  
while(nStartPos < nEndPos && !bStop) %m5&Y01  
{ r 1x2)  
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try{ ~qu}<u)P  
URL url = new URL(sURL); /ho7O/aAa  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ;T,`m^@zf  
httpConnection.setRequestProperty("User-Agent","NetFox"); A/A;'9  
String sProperty = "bytes="+nStartPos+"-"; +{dJGPoY]p  
httpConnection.setRequestProperty("RANGE",sProperty); T_NN.Ol  
Utility.log(sProperty); qvN`46c  
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InputStream input = httpConnection.getInputStream(); 7
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//logResponseHead(httpConnection); )r|Pm-:A{  
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byte[] b = new byte[1024]; cI/
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int nRead; r'E|6_0  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) mi&mQQ  
{ dZIruZ)x
 
nStartPos += fileAccessI.write(b,0,nRead); X*QQVj
 
//if(nThreadID == 1) 2Cgq&\wS  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); NS3qNj  
} 1kdQh&~G  
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Utility.log("Thread " + nThreadID + " is over!"); d:{#Dk#  
bDownOver = true; [+.P'6/[$R  
//nPos = fileAccessI.write (b,0,nRead); }h=}!R'm   
} >Nr~7s  
catch(Exception e){e.printStackTrace ();} 1P6!E*z\  
} vL ]z3  
} e4<[|B!O  
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//打印回应的头信息 2}xvM"k=k  
public void logResponseHead(HttpURLConnection con) Wa!}$q+  
{ \yKYBfp-p  
for(int i=1;;i++) ?j|i|WUD  
{ + )lkHv$R  
String header=con.getHeaderFieldKey(i); DNmP>~  
if(header!=null) (*Fb/  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 2'T uS?  
Utility.log(header+" : "+con.getHeaderField(header)); MNWuw;:v  
else 4khc*fh  
break; C $*#<<G  
}  Ds@nuQ  
} C]GW u~QF  
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public void splitterStop() YX{c06BHs  
{ E*G{V j  
bStop = true; ]3&BLq  
} /P koqA,  
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} )FSa]1t;x  
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/* i/{`rv*K[  
**FileAccess.java w6<zPrA  
*//文件访问(定位，写) F$nc9x[S  
package NetFox; @0&KM|+  
import java.io.*; Ro
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public class FileAccessI implements Serializable{ ;JV(!8[  
/?_5!3KJ  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 <&MY/vV  
RandomAccessFile oSavedFile; F*J@OY8i  
long nPos; ,]H2F']4Z  
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public FileAccessI() throws IOException G-Dc(QhU&  
{ b 67l\L  
this("",0); cu )w6!f  
} wq =Ef  

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public FileAccessI(String sName,long nPos) throws IOException 9?.  
{ =niT]xf  
oSavedFile = new RandomAccessFile(sName,"rw"); mT&?DZ9<  
this.nPos = nPos; +XoY@|Djd  
oSavedFile.seek(nPos); =kDh:&u%  
} +Vw]DLWR  
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M=#'+CF}W  
public synchronized int write(byte[] b,int nStart,int nLen) vV*i)`IXe  
{ :O/QgGZN$  
int n = -1; R}T\<6Y  
try{ X6G2$|  
oSavedFile.write(b,nStart,nLen); }[b3$WZ  
n = nLen; 'v0(ki#  
} 7(plHW|  
catch(IOException e) i(an]%'v  
{ QUKv :;  
e.printStackTrace (); }2.0e5[  
} 9six]
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return n; 1dl(`=^X  
} aU?HIIA  
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} 0+3{fD/  
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/* #j4jZBOTM  
**SiteInfoBean.java G^2%F5@  
*/ ^ RIWW0  
package NetFox; S:{`eDk\A_  
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public class SiteInfoBean { P&5kO;ia  
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private String sSiteURL; //Site's URL xFp?+a  
private String sFilePath; //Saved File's Path l9vJ]  
private String sFileName; //Saved File's Name @BoZZ  
private int nSplitter; //Count of Splited Downloading File y7U?nP ')+  
tf4clzSTa  
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public SiteInfoBean() ES ?6  
{//nSplitter的缺省值为5 :@#6]W  
//default value of nSplitter is 5 80"oT'ZFh  
this("","","",5); Z}yd`7  
} Q=h37]U+  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ]/{iIS_  
{ 1{.5X8y1x  
sSiteURL= sURL; ;YYnIb(  
sFilePath = sPath; v{pW/Fu~  
sFileName = sName; 04#<qd&ob@  
this.nSplitter = nSpiltter; 0S&C[I o6  
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} oq[r+E-]$@  
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public String getSSiteURL() cQrXrij;!  
{ 9yWSlbPr]  
return sSiteURL; Dn:1Mtj-  
} ccwz:7r  
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public void setSSiteURL(String value) ?\_vqW  
{ GC7W7B  
sSiteURL = value; =kjD ]+l  
} K&BaGrR  
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public String getSFilePath() =5
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{ X
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return sFilePath; q@i.4>x  
} /$^SiE+N  
5MK.>3fE  
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public void setSFilePath(String value) 3:bP>l!  
{ SK5__Ix  
sFilePath = value; s){R/2O3F  
} BiA^]h/|  
VVqpzDoXG  
#>2cfZ`6'J  
public String getSFileName() ,15$$3z/E  
{ jvhD_L/  
return sFileName; ^ #3,*(S  
} ,{d=<j_  
G%U!$\j:qd  
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public void setSFileName(String value) e}ivvs2  
{ $]MOAj"LH  
sFileName = value; U04)XfO;]  
} !,{-q)'D  
-BH T'zq1S  
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public int getNSplitter() n<Ki.;-ZE  
{ O@>{%u  
return nSplitter; at(gem   
} (I;lE*>  
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R)Dh;XA  
public void setNSplitter(int nCount) o<rbC < U  
{ !L)yI#i4C  
nSplitter = nCount; `+(4t4@ew  
} 7e /Kh)5G  
} VM+l9z>  
}]. |7h  
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/* k[\JT[M
p  
**Utility.java ~>$z1o&}.  
*/ 5Zl7crA[  
package NetFox; 1~vv<`-  
ZVz*1]}  
*}Rd%'  
public class Utility { n"<'F4r  
X [;n149o  
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public Utility() \3whM6tK  
{ 0gr#<(  
c[EG cY={  
h8P_/.+g|V  
} 4g?qKoc i  
8xHjdQr  
//线程睡眠 }R`}Ey|{  
public static void sleep(int nSecond) '8b=4mrbH  
{ _#w5hXcu  
try{ a]
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Thread.sleep(nSecond); j2jUrl  
} Nrc-@ ]  
catch(Exception e) >Vb V<ak  
{ ;(IAhWE?7  
e.printStackTrace ();  =h}PL22  
} '>>@I~<\  
} n;k B_i*l  
<9`/Y"\p  
//日志 RMa#z [{0  
public static void log(String sMsg) vr$z6m ^  
{ $'bb)@_  
System.err.println(sMsg); M B,Z4 ^  
} dfs1BV'  
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public static void log(int sMsg) C12y_E8Un  
{ Hzc^fC  
System.err.println(sMsg); jxnb<!|?H@  
} tfjbG;R  
} uQkQ#'e|  
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qb5I
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/* #e6x_o|  
**TestMethod.java nG"Ae8r  
*/ }:+P{  
package NetFox; VqeW;8&*iv  
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HA. O"A8`  
public class TestMethod { bc\?y2 3  
~q{QquYV  
l%7^'nDn  
public TestMethod() w4Ku1G#jC  
{ ///xx/weblogic60b2_win.exe _2WIi/6K  
try{ M:w]g`LKl  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ~T&X#i  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); dZ\T@9+j+  
SiteFileFetch fileFetch = new SiteFileFetch(bean); LY!.u?D`P  
fileFetch.start(); zxvowM  
} (rSBzM]H  
catch(Exception e){e.printStackTrace ();} 6dYUMqQ  
@m"P_1`*  
>{juw&Uu  
} 8C2!Wwz`J8  
VB{G%!}  
R= *vPS  
public static void main(String[] args) m`/!7wQs  
{ [ ]=}0l
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new TestMethod(); U&y?3  
} sB`zk[R;  
} fhe%5#3  
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