http断点续传简单实现（java)

/* ])wMUJWg2  
**SiteFileFetch.java 5 EuJ  
*/ 8Y0<lfG  
package NetFox; [ 6o:v8&3  
import java.io.*; q\HBAry  
import java.net.*; 8
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public class SiteFileFetch extends Thread { <[5${)  
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SiteInfoBean siteInfoBean = null; //文件信息Bean H6JMN1#t$  
long[] nStartPos; //开始位置 Jx9%8Ek  
long[] nEndPos; //结束位置 v
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FileSplitterFetch[] fileSplitterFetch; //子线程对象 E|4XQ|B@  
long nFileLength; //文件长度 2V"gqJHv  
boolean bFirst = true; //是否第一次取文件 5GFnfc}  
boolean bStop = false; //停止标志 XK/@!ud"`  
File tmpFile; //文件下载的临时信息 (l P4D:X  
DataOutputStream output; //输出到文件的输出流 YxkEAb!+  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ?ZV0
 
public SiteFileFetch(SiteInfoBean bean) throws IOException ^oB1 &G  
{ 1&pP}v ?  
siteInfoBean = bean; IC-xCzR  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); PZhZK VZx  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); OK J%M]<  
if(tmpFile.exists ()) JHZo:Ad -&  
{ :=7'1H  
bFirst = false; x7
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read_nPos(); Xsn- +e  
} _]ttKT(  
else u
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{ h%^kA@3F  
nStartPos = new long[bean.getNSplitter()]; Lpbn@y26<  
nEndPos = new long[bean.getNSplitter()]; RMt vEa  
} _vLT!y  
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} Tc(v\|F,  
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public void run() <r`Jn49  
{ >~>[}d;glw  
//获得文件长度 jTgh+j]AP  
//分割文件 ;<@O^_+  
//实例FileSplitterFetch X$&Sw3c  
//启动FileSplitterFetch线程 *B<I><'G  
//等待子线程返回 ~+nSI-L  
try{ *3 8Y;{ 4  
if(bFirst) |#jm=rT0y  
{ -*l[:5m  
nFileLength = getFileSize(); [=1?CD  
if(nFileLength == -1) Msu2OF *x  
{ +&zCmkVC7  
System.err.println("File Length is not known!"); ye7&y4v+  
} N,,2VSUr  
else if(nFileLength == -2) <_q/ +x]8  
{ ;f^jB;\<  
System.err.println("File is not access!"); sx^? Iw,N'  
} ;Hr@0f  
else OjEA;;qq  
{ @VS5Mg8  
for(int i=0;i<nStartPos.length;i++) knzED~v@(  
{ OYp8r  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); }t-|^mY>  
} 3}1+"? s  
for(int i=0;i<nEndPos.length-1;i++) >qvD39w  
{ jeFl+K'1  
nEndPos = nStartPos[i+1]; ]b| @<E7Y  
} <d`UifqD  
nEndPos[nEndPos.length-1] = nFileLength; 6i9I 4*'  
} 2^M+s\p  
} ^ED>{UiNI  
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//启动子线程 h#ot)m|I  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; NS;8&  
for(int i=0;i<nStartPos.length;i++) b}*bgx@<  
{ &Q+V I/p  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ',j-n$Z^=  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), BD#;3?|  
nStartPos,nEndPos,i); d$~b`  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); OBSJbDqT  
fileSplitterFetch.start(); 6yM dl~
.  
} EoCwS  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), }B/xQsTx-  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); {*$J&{6V  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", HKw:fGt/o^  
nEndPos = " + nFileLength); F|Ihq^q  
// fileSplitterFetch[nPos.length-1].start(); HZ=yfJs nc  
g|_*(=Q  
?R:Hj=.  
//等待子线程结束 ve^MqW&S  
//int count = 0; 2U{RA's  
//是否结束while循环 }PL  
boolean breakWhile = false; k ,(:[3J  
i~L7h=__  
+= ~}PF  
while(!bStop) HbDB
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{
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write_nPos(); ?.ihWbW_  
Utility.sleep(500); qW>J-,61/  
breakWhile = true; #[y
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for(int i=0;i<nStartPos.length;i++) tb\pjLB][  
{ S]g)^f'a65  
if(!fileSplitterFetch.bDownOver) 4O^1gw  
{ r=aQS5  
breakWhile = false; F[Sat;Sll  
break; dtl<  
} :|3C-+[  
} <);u]0
  
if(breakWhile) Ec 7M'~1  
break; h8Si,W3o  
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//count++; 9Wrclai  
//if(count>4) 0pOha(,~  
// siteStop(); TaT&x_v^~a  
} nCB3d[/B  
9Bw"VN]W  
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System.err.println("文件下载结束！"); cA2]VL.r>C  
} # t Ki6u  
catch(Exception e){e.printStackTrace ();} ~A4WuA  
} 0eP~F2<bC  
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p~ItHwiT  
//获得文件长度 c'R|Wyf  
public long getFileSize() ^]gl#&"D  
{ @CDRbXoFk  
int nFileLength = -1; #JucOWxjY  
try{ rID]!7~  
URL url = new URL(siteInfoBean.getSSiteURL()); _*I6O$/>  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 1Tr=*b %f  
httpConnection.setRequestProperty("User-Agent","NetFox"); yQ50f~9  
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int responseCode=httpConnection.getResponseCode(); ?,C,q5 T\  
if(responseCode>=400) :tG5~sK  
{ }3lF;k(2g  
processErrorCode(responseCode); 69yyVu_  
return -2; //-2 represent access is error 92Iv'(1ba  
} blv6  
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String sHeader; u*`GIRfWT  
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for(int i=1;;i++) tm?  
{ iX p8u**  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); B,T.bgp\  
//Utility.log(in.readLine()); `^vD4qD|  
sHeader=httpConnection.getHeaderFieldKey(i); _Tz!~z  
if(sHeader!=null) 8w'8n  
{ %xz02$k  
if(sHeader.equals("Content-Length")) sNVD"M,  
{ S(l^TF  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); iI0'z=J  
break; \-yi#N  
} "(qO}&b>  
} -X \vB  
else 7F\g3^z9`  
break; I|H mbTXa  
} $h9!"f[|j  
} e>.xXg6Zn  
catch(IOException e){e.printStackTrace ();} +\chHOsw  
catch(Exception e){e.printStackTrace ();} b}*hodzF  
f *vziC<m  
9qA_5x%"%u  
Utility.log(nFileLength); }=FQKqtC  
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return nFileLength; *TkABUL  
} f?6=H^_>  
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//保存下载信息（文件指针位置） 9h8G2J o  
private void write_nPos() /([aD~.  
{ x;Q2/YZ#  
try{ oP6G2@3P/  
output = new DataOutputStream(new FileOutputStream(tmpFile)); hlZjk0ez  
output.writeInt(nStartPos.length); J4i0+u  
for(int i=0;i<nStartPos.length;i++) /'&LM\  
{ { L5m`-x  
// output.writeLong(nPos); v5o%y:~  
output.writeLong(fileSplitterFetch.nStartPos); FCPbp!q6  
output.writeLong(fileSplitterFetch.nEndPos); F/Xhm91^  
} jG#sVK]  
output.close(); iVcBD0 q)  
} X1"nq]chGy  
catch(IOException e){e.printStackTrace ();} zqkmsFH{  
catch(Exception e){e.printStackTrace ();} 9^tyjX2  
} {PKER$C  
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n9^zAcUbAW  
//读取保存的下载信息（文件指针位置） o%a$m9I  
private void read_nPos() 3'wBX  
{ M*N8p]3Cq  
try{ )UJMmw\  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Fh'Jb*|Q  
int nCount = input.readInt(); mqL+W  
nStartPos = new long[nCount]; <#-ERQw  
nEndPos = new long[nCount]; Tp7?:YY|  
for(int i=0;i<nStartPos.length;i++) .(-3L9T}  
{ Sy_M!`B  
nStartPos = input.readLong(); 7vFqO;  
nEndPos = input.readLong(); ;1nd~0
o  
} q,GL#L  
input.close(); )r~Oj3TH  
} OsXQWSkj~  
catch(IOException e){e.printStackTrace ();} >/*\xg&J  
catch(Exception e){e.printStackTrace ();} <#UvLll  
} `t -3(>P  
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;/
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private void processErrorCode(int nErrorCode) ~U|te_l  
{ @WmB0cc_  
System.err.println("Error Code : " + nErrorCode); RjT[y: !  
} jv ";?*I6.  
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0/Csc\Xl  
//停止文件下载 cQny)2k*x  
public void siteStop() I zT%Kq  
{ k8TMdWW  
bStop = true; >&R|t_ypw  
for(int i=0;i<nStartPos.length;i++) .JqIAC~  
fileSplitterFetch.splitterStop(); .o>QBYpTw/  
RwE]t$T/  
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} ZD/!C9:&.0  
} ;p/@tr9  
//负责部分文件的抓取 8c9_=8vw  
**FileSplitterFetch.java &Ru6Yt0W  
*/ Dz?F,g_  
package NetFox; c
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import java.io.*; Z8x(_ft5  
import java.net.*; C9h8d
 
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public class FileSplitterFetch extends Thread { o|+tRl  
F~B8XUa3  
Ah,Zm4:  
String sURL; //File URL i[<O@Rb  
long nStartPos; //File Snippet Start Position 6Z$T&Ul{  
long nEndPos; //File Snippet End Position W
+S>/`N  
int nThreadID; //Thread's ID k`-L5#
`  
boolean bDownOver = false; //Downing is over X7G6y|4;w  
boolean bStop = false; //Stop identical ()rDM@  
FileAccessI fileAccessI = null; //File Access interface Abl=Ev  
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p7*\]HyE)  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException &"BKue~q@p  
{ R1nctA:  
this.sURL = sURL; 8wBns)wy@  
this.nStartPos = nStart; |^1eL I  
this.nEndPos = nEnd; qRUz;M4  
nThreadID = id; yoH6g?!O  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 'D1@+FFU0  
} X#J[Nn>  
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public void run() ,YoIn  
{ Gqs8$[o  
while(nStartPos < nEndPos && !bStop) SbB5J> >7J  
{ Z'EZPuZ!'  
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try{ P=h2Z,2  
URL url = new URL(sURL); yCz
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); AOTI&v  
httpConnection.setRequestProperty("User-Agent","NetFox"); y]Y)?])  
String sProperty = "bytes="+nStartPos+"-"; 8Vq,J:+  
httpConnection.setRequestProperty("RANGE",sProperty); y]/{W}D  
Utility.log(sProperty); 9+L! A  
Q/< $ (Y  
?D.]c;PR  
InputStream input = httpConnection.getInputStream(); 3}H94H)]a  
//logResponseHead(httpConnection); (Yx rZ_F'b  
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byte[] b = new byte[1024]; Y4i-Pp?  
int nRead; DzYno-]A]  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 9gFC]UVWh  
{ s~GO-v7  
nStartPos += fileAccessI.write(b,0,nRead); k -SUp8}g  
//if(nThreadID == 1) Dr;@)  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); fD!O aK  
} MPT[f  
X1+Wb9P  
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Utility.log("Thread " + nThreadID + " is over!"); 3&}wfK]X  
bDownOver = true; /_LUys/0  
//nPos = fileAccessI.write (b,0,nRead); 7c+u+Yet  
} %3q@\:s  
catch(Exception e){e.printStackTrace ();} 0s4%22  
} j"c"sF\q  
} r`" ?K]rI  
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d=x
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//打印回应的头信息 m86w{b$8  
public void logResponseHead(HttpURLConnection con) p<$z!|7m  
{ 8(BLS{-"<  
for(int i=1;;i++) Q<"zpwHR  
{ f$P pFSY4  
String header=con.getHeaderFieldKey(i); g6N{Z e Wg  
if(header!=null) w7O(I"  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); D[U5SS!)  
Utility.log(header+" : "+con.getHeaderField(header)); /P,J);Y  
else ?bbguwo~F  
break; IH{g-#U  
} dLv\H&  
} ecr pv+  
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75{QBlf<  
public void splitterStop() W$,c]/u|  
{ [/#;u*n  
bStop = true; z7J#1q~:yY  
} Pj+XKDV]T  
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b-ZvEDCR  
} %[RLc[pB  
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wJ+"JQY.J+  
/* TVKuvKH8U  
**FileAccess.java hMi[MB7~  
*//文件访问(定位，写) xHI>CNC,  
package NetFox; D7 .R NXo  
import java.io.*; @v|_APy#  
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public class FileAccessI implements Serializable{ m%m8002  
H]YPMG<  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ]{dg"J  
RandomAccessFile oSavedFile; "Sl";.  
long nPos; 3 bGpK9M~  
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public FileAccessI() throws IOException _t3n<  
{ I,.>tC  
this("",0); w${=]h*2  
} Cvq2UNz(R  
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public FileAccessI(String sName,long nPos) throws IOException 9QZ;F4 r  
{ Xa+ u>1"2"  
oSavedFile = new RandomAccessFile(sName,"rw"); Ao 1*a%-.  
this.nPos = nPos; h@l5MH=|%  
oSavedFile.seek(nPos); :tNH Cx  
} v2dCna\  
3%'$AM}+s  
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public synchronized int write(byte[] b,int nStart,int nLen) Nf
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{ %KRAcCa7  
int n = -1; Vhv<w O Ct  
try{ ]{Iy<  
oSavedFile.write(b,nStart,nLen); &rk/ya[  
n = nLen; 9V("K  
} S_aml  
catch(IOException e) TDA+ rl  
{ :jgwp~l  
e.printStackTrace (); =p:D_b  
}  >Xh9{/o  
:*#I1nb$  
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return n; ABB4(_3E  
} *r$(lf  
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} !bS:!Il9=  
}JoCk{<31  
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/* <e)3 j6F!  
**SiteInfoBean.java &p`RKD  
*/ 5 J61PuH   
package NetFox; I[G<aI!  
D8qZh1w%A|  
5&\Q0SX(~  
public class SiteInfoBean { #8QQZdC8`  

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n;y<!L7  
private String sSiteURL; //Site's URL v|"Nx42  
private String sFilePath; //Saved File's Path rx CSs  
private String sFileName; //Saved File's Name ) j_g*<  
private int nSplitter; //Count of Splited Downloading File A9!%H6  
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public SiteInfoBean() a>G|t5w  
{//nSplitter的缺省值为5 &%$r3ePwc  
//default value of nSplitter is 5 1|Us"GQ(n  
this("","","",5); &AG,]#  
} e@F9'z4  
m = "N4!  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) DI"mi1ObE  
{ Rku9? zf^  
sSiteURL= sURL; U8PSJ0ny  
sFilePath = sPath; EQET:a:
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sFileName = sName; JFIUD{>fp  
this.nSplitter = nSpiltter; YcBY[i0  
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} '!I^Lfz-Z  
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public String getSSiteURL() " +'E  
{ RU|{'zC\v  
return sSiteURL; i"p)%q~ z  
} HY4X;^hF  
ri<E[8\  
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public void setSSiteURL(String value) 7loIX Qw  
{ !'Q/9%g  
sSiteURL = value; |X,T>{V?y  
} pdX%TrM+[:  
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public String getSFilePath() sk.<|-(o  
{ <O>1Y09C/  
return sFilePath; Po#;SG#Ee  
} yZE"t[q#O  
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public void setSFilePath(String value) 2;VggPpT  
{ Z?kLAhy!  
sFilePath = value; C: @T5m
 
} WLma)L`L  
9 ,=7Uh#7  
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public String getSFileName() 0'{0kE[wn  
{ /f@VRME  
return sFileName; nw){}g  
}  m_LW<'  
i Tg?JoE2  
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public void setSFileName(String value) Hr |De8#f  
{ k>I[U}h  
sFileName = value; 9=p^E#d  
} =\GuIH2  
0!!b(X(  
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public int getNSplitter() wg\*FfQn  
{ yJkERiJV  
return nSplitter; ^AS*X2y  
} UT|FV twO  
5-3`@
(/  
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public void setNSplitter(int nCount) 5}@6euT5$  
{ ;+t~$5  
nSplitter = nCount; ~$-Nl  
} 5RCZv\Wd&  
} qPY OO  
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/* E$"( :%'v  
**Utility.java l=G=J(G  
*/ !_P;4E  
package NetFox; Nn5z   
q] eSDRW  
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public class Utility { Ch8w_Jf1yx  
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public Utility() 5|&8MGW-$  
{ WlVp|s{TYP  
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} *$mDu,'8  

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//线程睡眠 ZWH?=Bk:  
public static void sleep(int nSecond) W&23M26"{  
{ s\A"B#9r  
try{ Q|/uL`_ni  
Thread.sleep(nSecond); 8q*MhH>6I  
} U9GmkXRix  
catch(Exception e) eV$pza  
{ mVFz[xI  
e.printStackTrace (); $xqI3UaX  
} <Hw)},_*  
} %"Tn=fZIF  
'wB6-  
//日志 Rd7[e^HSN  
public static void log(String sMsg) <20rxOEnf  
{ 04>dxw)8  
System.err.println(sMsg); <$!^LKKzA  
} !pY=\vK;  
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e
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public static void log(int sMsg) MN1 kR  
{ -{H;w=9  
System.err.println(sMsg); }
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} aN9#ATE  
} /c
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Y Y4"r\V  
E=!=4"rZF  
/* $@k[Xh  
**TestMethod.java 8;2UP`8s?  
*/ am;)@<8~Q  
package NetFox; %%
J)@k^vH  
Z
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pGEYke NU  
public class TestMethod { 8l,`~jvU!*  
h#a;(F4_7  
pUtd_8  
public TestMethod() OL+dx`Y  
{ ///xx/weblogic60b2_win.exe 0IU>KGJ-0s  
try{ PAG.],"D  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); GQ<]Sd}
[  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); h&Thq52R  
SiteFileFetch fileFetch = new SiteFileFetch(bean); |tL57Wu93  
fileFetch.start(); tj:3R$a  
} ANB@cK_  
catch(Exception e){e.printStackTrace ();} \\;i  
<s/n8#i=H  
7d&_5Tj:  
} g3[Zh=+]E  
<WXO].^  
U^jxKBq^  
public static void main(String[] args) Cw`8[)=}o  
{ )X*?M?~\  
new TestMethod(); p0Cp\.  
} `CCuwe<v  
} aRFLh  
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