http断点续传简单实现（java)

/* B~E">}=!  
**SiteFileFetch.java %W8iC%~  
*/  B$6KI  
package NetFox; E}KGZSj  
import java.io.*; $#-rOi /  
import java.net.*; n 7i5A:  
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ht*(@MCr<  
public class SiteFileFetch extends Thread { \i/HHP[%  
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 =  
SiteInfoBean siteInfoBean = null; //文件信息Bean IA<>+NS  
long[] nStartPos; //开始位置 .8Bu%Sf  
long[] nEndPos; //结束位置 `kJ)E;v;3  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Pjk2tf0j`  
long nFileLength; //文件长度 ]E-3/r$_cO  
boolean bFirst = true; //是否第一次取文件 1I`F?MT  
boolean bStop = false; //停止标志 _?:jZ1wZ  
File tmpFile; //文件下载的临时信息 Arg/g
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DataOutputStream output; //输出到文件的输出流 5
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） {f\wIZ-K A  
public SiteFileFetch(SiteInfoBean bean) throws IOException L{P'mG=4  
{ {QM rgyQE  
siteInfoBean = bean; dkz% Y]  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); /M%>M]  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ,IyQmN y  
if(tmpFile.exists ()) (ne[a2%>  
{ a51e~mg Z`  
bFirst = false; !Pw*p*z  
read_nPos(); |J,zU6t  
} aSvv(iV  
else !Ztqh Xr  
{ _]OY[&R  
nStartPos = new long[bean.getNSplitter()]; JyZuj>` 6  
nEndPos = new long[bean.getNSplitter()]; o *J*}y  
} #Z1-+X8P  
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} jcJ 4?  
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public void run() yf9"Rc~+  
{ z )'9[t  
//获得文件长度 h
40;Q<D  
//分割文件 ##6\~!P  
//实例FileSplitterFetch .p! DVQ"a  
//启动FileSplitterFetch线程 YK)m6zW5  
//等待子线程返回 gMI%!Y  
try{ }yK7LooM  
if(bFirst) x6`mv8~9Db  
{ >O?WRCB  
nFileLength = getFileSize(); 8In\Jo$|q>  
if(nFileLength == -1) |-x-CSN  
{ n"htx|v  
System.err.println("File Length is not known!"); OW@%H;b  
} Jz`jN~  
else if(nFileLength == -2) BDI@h%tJb:  
{ :oZ<[#p"*  
System.err.println("File is not access!"); 6p4BsWPx  
} 2.aCo, Kb;  
else QcL@3QC  
{ 20V~?xs~  
for(int i=0;i<nStartPos.length;i++) Zu,:}+niU  
{ `.MZ,Xhqi"  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); (U.Go/A#wE  
} ;|WUbc6&g  
for(int i=0;i<nEndPos.length-1;i++) OM[MRZEh G  
{ D{N8q^Cs9  
nEndPos = nStartPos[i+1]; GK}
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} M!J7Vj?Ps  
nEndPos[nEndPos.length-1] = nFileLength; + f67y  
} ri{*\LV*@  
} T
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vW=-RTRH  
Qp:I[:Lr;  
//启动子线程 xn3 _ED  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; i]r(VKX  
for(int i=0;i<nStartPos.length;i++) )$:1e)d  
{ 8X7??f1;Y  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), -x+3nb|.  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), G$>?UQ[  
nStartPos,nEndPos,i); ekhv.;N~  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 3:x(2 A  
fileSplitterFetch.start(); A0Mjk  
} X(
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// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), tLy:F*1i  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ^xa, r#N:V  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", RE;A0E_3  
nEndPos = " + nFileLength); "#iJ/vy  
// fileSplitterFetch[nPos.length-1].start(); _p*9LsN$L  
I1fpX |  
j+_fHADq  
//等待子线程结束 BX?DI-o^h  
//int count = 0; _iJ~O1qx,w  
//是否结束while循环 8z1z<\  
boolean breakWhile = false; j9NF|  
b)I-do+  
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while(!bStop) O=2|'L'h!  
{ I_<VGUk  
write_nPos(); 6j(/uF4!#  
Utility.sleep(500); vUpAW[[  
breakWhile = true; g0grfGo2p  
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for(int i=0;i<nStartPos.length;i++) P4[kW}R  
{ >$
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if(!fileSplitterFetch.bDownOver) oN1D&*  
{ Wi&v?nm  
breakWhile = false; XR+ SjCA  
break; 0VNLhM(LM  
} !rUP&DA  
} l53i {o  
if(breakWhile) >_?i)%+)  
break; TwkT|Piw S  
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//count++; (A~7>\r +  
//if(count>4) 0#]fEi  
// siteStop(); Bg~]
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} z
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OMLU ;,4  
System.err.println("文件下载结束！"); ^>IP"kF  
} {fXkbMO|  
catch(Exception e){e.printStackTrace ();} =p@`bx  
} XZ%,h  
]rlZP1".  
^~H}N$W"-q  
//获得文件长度 eg;7BZim{  
public long getFileSize() Fv~lasW[  
{ _RIU,uJs  
int nFileLength = -1; p1KhI;^  
try{ DU!T#H7  
URL url = new URL(siteInfoBean.getSSiteURL()); '3l TI  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); B#V""[Y9  
httpConnection.setRequestProperty("User-Agent","NetFox"); *cb|9elF^  
/whaY4__O\  
)7 p" -  
int responseCode=httpConnection.getResponseCode(); =?OU^u`C  
if(responseCode>=400) OXQ*Xpc  
{ :TQp,CEa  
processErrorCode(responseCode); Ixxs(  
return -2; //-2 represent access is error Pm/<^z%  
} xWG@<}H  
M|DMoi8x  
u} mj)Nk  
String sHeader; Wu][A\3D1  
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for(int i=1;;i++) 7%^G]AFi  
{ JH.XZM&  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); P)Adb~r  
//Utility.log(in.readLine()); cu/"=]D  
sHeader=httpConnection.getHeaderFieldKey(i); N )Z>]&5  
if(sHeader!=null) W;OGdAa_  
{ _EMI%P&s  
if(sHeader.equals("Content-Length")) gQ\.|'%  
{ GeR#B;{  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ?Q]&;5o  
break; GY$Rkg6d  
} .RxTz9(  
} ,t`V^(PEq  
else vvxxwZa=O  
break; Nn05me"X  
} W2
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} MLdwf}[  
catch(IOException e){e.printStackTrace ();} 2b$>1O&2  
catch(Exception e){e.printStackTrace ();} V8n {k'  
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,%9XG077
 
Utility.log(nFileLength); Vh\_Ko\V5  
}QI \K  
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return nFileLength; <,~OcJG(   
} x/s:/YN'  
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WESD^FK  
//保存下载信息（文件指针位置） bsQ'kBD  
private void write_nPos() NljpkeX'  
{ (ks>F=vk*  
try{ M1Q&)am  
output = new DataOutputStream(new FileOutputStream(tmpFile)); t
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output.writeInt(nStartPos.length); e1Db +QBV  
for(int i=0;i<nStartPos.length;i++) s$#64"F  
{ &[d'g0pF  
// output.writeLong(nPos); p cLKE ZK  
output.writeLong(fileSplitterFetch.nStartPos); 31G:[;g  
output.writeLong(fileSplitterFetch.nEndPos); +~"IF+TRH  
} Exwd,2>  
output.close(); ,Q"'q0hM=  
} k[x-O?$O@  
catch(IOException e){e.printStackTrace ();} K
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catch(Exception e){e.printStackTrace ();} `:C1Wo^<  
} n5QO'Jr%[  
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Vl^x_gs#_]  
//读取保存的下载信息（文件指针位置） &;$uU  
private void read_nPos() 2U./ Yfk\  
{ =zn'0g,J4  
try{ dy6zrgxygP  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 2? E;(]dQ  
int nCount = input.readInt(); 1|sem(t  
nStartPos = new long[nCount]; VD.TosVeWo  
nEndPos = new long[nCount]; MXSD8]
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for(int i=0;i<nStartPos.length;i++) g(&cq  
{ H>+/k-n-  
nStartPos = input.readLong(); t=7Gfv
 
nEndPos = input.readLong(); UuIjtqW  
}  9tpyrGv  
input.close(); ika*w  
} E]#;K-j  
catch(IOException e){e.printStackTrace ();} <J^5l0)q  
catch(Exception e){e.printStackTrace ();} \6 \bD<  
} L\4rvZa  
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private void processErrorCode(int nErrorCode) mu B Y  
{ J^"_H:1[  
System.err.println("Error Code : " + nErrorCode); *9n[#2sM<  
} C@-Hm  
8>x5
|  
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//停止文件下载 'ON/WKJr|W  
public void siteStop() le5@WG/x  
{ URVW5c  
bStop = true; 5j`sJvq  
for(int i=0;i<nStartPos.length;i++) 8$-MUF,  
fileSplitterFetch.splitterStop(); 6Jgl"Jw8  
j"jssbu}  
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} JlSqTfA  
} yD<#Q\,  
//负责部分文件的抓取 \gP?uJ  
**FileSplitterFetch.java ,i*rHMe  
*/ `)O9 '568  
package NetFox; N~|f^#L  
q;AD#A|\  
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import java.io.*; Y's=31G@  
import java.net.*; }P2*MrkcHB  
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public class FileSplitterFetch extends Thread { ;*5z&1O  
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9?Bh8%$  
String sURL; //File URL hEjvtfM9\-  
long nStartPos; //File Snippet Start Position "0!#De  
long nEndPos; //File Snippet End Position 6ud?US(  
int nThreadID; //Thread's ID D?ic~-&  
boolean bDownOver = false; //Downing is over z\v  
boolean bStop = false; //Stop identical I6WHC*  
FileAccessI fileAccessI = null; //File Access interface ;FlDRDZ%  
@IL@|Srs8  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Q8HNST($?  
{ 0^{Tq0Ri[  
this.sURL = sURL; YEV;GFI1  
this.nStartPos = nStart; f.ua,,P.  
this.nEndPos = nEnd; N_D=j6B  
nThreadID = id; T \34<+n1N  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 d)48m}[:  
} 70avr)OM  
C
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public void run() 6 w!qZ4$  
{ ="T}mc  
while(nStartPos < nEndPos && !bStop) -)J*(7F(6^  
{ tDAX pi(  
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try{
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URL url = new URL(sURL); wOUCe#P|r  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); '!X`X=  
httpConnection.setRequestProperty("User-Agent","NetFox"); pz2E+o  
String sProperty = "bytes="+nStartPos+"-"; }Bh\N5G%  
httpConnection.setRequestProperty("RANGE",sProperty); '1!%yKc0  
Utility.log(sProperty); S%p,.0_  
^p4`o>  
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InputStream input = httpConnection.getInputStream(); >CCy2W^W  
//logResponseHead(httpConnection); s,J\nbj0h  
f[zKA{R  
,9|7{j|u  
byte[] b = new byte[1024]; v'L"sgW6I  
int nRead; d;%~\+)x4  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) (|W6p%(  
{ lS;S:- -F  
nStartPos += fileAccessI.write(b,0,nRead); \U]<HEc^  
//if(nThreadID == 1) [HXd|,~_j-  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); El`G<esX  
} S@\&^1;4Hv  
un6W|
{4]  
;|rFP  
Utility.log("Thread " + nThreadID + " is over!"); 6mZpyt  
bDownOver = true; 2QHu8mFU  
//nPos = fileAccessI.write (b,0,nRead); a"O9;&};&  
} g7%vI8Y)@  
catch(Exception e){e.printStackTrace ();} _z^&zuO  
} ^CwS'/fdN  
} Z1H  
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<y-2ovw*  
//打印回应的头信息 yj,+7[)  
public void logResponseHead(HttpURLConnection con) v]drDVJ   
{ yaj1nq!*"  
for(int i=1;;i++) w2"]%WS%  
{ 7<Ut/1$MI  
String header=con.getHeaderFieldKey(i); |b Z 58{}  
if(header!=null) H_JT"~_2  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); }LBrk0]  
Utility.log(header+" : "+con.getHeaderField(header)); -J!k|GK#MX  
else Iq;a!Lya-  
break; #$t93EI  
} ZCuh^  
} ng2yZ @$  
78z/D|{"  
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public void splitterStop() My9fbT  
{ q[Y*.%~  
bStop = true; YWhS<}^  
} 1p>&j%dk  
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@(st![i+  
} Q!Dr3x  
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53^1;  
/* AQBr{^inH|  
**FileAccess.java xJzO?a'  
*//文件访问(定位，写) . =A|  
package NetFox; ">I50#bT  
import java.io.*; () HIcu*i  
4s&koH(x  
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public class FileAccessI implements Serializable{ fl9J  
N'5!4JUI  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 M\9p-%"L  
RandomAccessFile oSavedFile; 0Ioa;XgOn  
long nPos; EJrQ9"x&n  
rFv=j:8  
o2(*5*b!@e  
public FileAccessI() throws IOException @6DV?VL  
{ -,xsUw4  
this("",0); My>{;n=}  
} W^nG\"T^  
== i?lbj  
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public FileAccessI(String sName,long nPos) throws IOException EEp,Z`  
{ ~_L_un.R  
oSavedFile = new RandomAccessFile(sName,"rw"); G5x%:,n  
this.nPos = nPos; b!|c:mE9|  
oSavedFile.seek(nPos); T*C]:=)  
} W[W}:@KZ  
t5za$kW'&  
2}R)0][W  
public synchronized int write(byte[] b,int nStart,int nLen) ?Da!QH >,]  
{ 8
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int n = -1; 3m`y?Dd  
try{ r(qU~re'  
oSavedFile.write(b,nStart,nLen); Pd<>E*>}c.  
n = nLen; {@[z-)N7\,  
} Z4Qq#iHZR  
catch(IOException e) X6@G)68  
{ Ik|nL#JH]  
e.printStackTrace (); ~lLIq!!\  
} ugt|'i  
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nz]+G2h  
return n; 6ax|EMw  
} X
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oW/ #/;|`  
) crhF9!4  
} F4Gv=q)Z  
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/* D@>^_cTO24  
**SiteInfoBean.java `=3:*.T*  
*/ 4jl
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package NetFox; Ik4U+
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j!P]xl0vOZ  
public class SiteInfoBean { H6XlS
j  
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private String sSiteURL; //Site's URL #4*~ 4/  
private String sFilePath; //Saved File's Path vN%SN>=L<  
private String sFileName; //Saved File's Name (-(sBQa+  
private int nSplitter; //Count of Splited Downloading File #Hr>KQ5mJQ  
ZK@ENfG  
H?>R#Ds-  
public SiteInfoBean() !7-dqw%l  
{//nSplitter的缺省值为5 w+~s}ta2^  
//default value of nSplitter is 5 %A dE5HI-  
this("","","",5); .pOTIRbA  
} _ZfJfd~  
rBZ0(XSZQ  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) y
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{ n_51-^*z  
sSiteURL= sURL; 64>o3Hb2  
sFilePath = sPath; ]?`t spm<t  
sFileName = sName; =q(;g]e  
this.nSplitter = nSpiltter; PI#xRKt  
Ln})\ UDK)  
xCMcS~ 3/  
} @4D$Xl  
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public String getSSiteURL() iii2nmiK  
{ !;^sIoRPV  
return sSiteURL; I7hE(2!$  
} n%]1p36  
0BM3:]=wr  
)q\|f_  
public void setSSiteURL(String value) TC4W7}}  
{ Ii/#cdgF  
sSiteURL = value; ,tZWPF-  
} Uzb~L_\Rmt  
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&C+pen)Z  
public String getSFilePath() nxP>IfSA  
{ 9air"4  
return sFilePath; w
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} mpBSd+;Z  
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public void setSFilePath(String value) ([='LyH];z  
{ R;gN^Yjk:  
sFilePath = value; PG8|w[V1"  
} I_
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public String getSFileName() c@%:aiEl  
{ X/fk&Cp  
return sFileName; F`;oe[wfk  
} t/\J  
++Qg5FukR  
Cyg\FHs  
public void setSFileName(String value) WUSkN;idVG  
{ MMglo3  
sFileName = value; jiMI&cl  
} & Me%ZM0  
'Jww}^h1  
e.%` tK3J  
public int getNSplitter() K%ltB&  
{ o[W7'1O  
return nSplitter; vd>X4e^j  
} /ov&h;  
4~8++b1/;  
G/Nb@pAy[  
public void setNSplitter(int nCount) pmR6(/B#  
{ rYbb&z!u  
nSplitter = nCount; L\--h`~YU  
} p=vu<xXtD  
} FWv-_  
)>$@cH  
<o8j+G)K#  
/* ^b=9{.5  
**Utility.java ^~k2(DLk  
*/ @bQf =N+  
package NetFox; 1-4iy_d  
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wiXdb[[#  
public class Utility { 8_6\>hW&  
e#MEDjm/)g  
lL.3$Rp;  
public Utility() {k=H5<FV  
{ h=uwOi6}  
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} y<bA Y_-[  
2yk32|  
//线程睡眠 6vySOVMj  
public static void sleep(int nSecond) :!a'N3o>  
{ 8{aS$V"  
try{ I^*&u,  
Thread.sleep(nSecond); '`$z!rA  
} )# le|Rf  
catch(Exception e) T2
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{
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e.printStackTrace (); ]]~tFdh  
} E^z\b *  
} E_-3G<rt  
>h+[#3vD  
//日志 K]4XD1n7  
public static void log(String sMsg) V3j1M?>  
{
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System.err.println(sMsg); )&R^J;W$M1  
} CPssk,q~C  
\~|+*^e)  
qP6YnJWl  
public static void log(int sMsg) q 65mR!)  
{ "L'
0"  
System.err.println(sMsg); ,f ..46G  
} &VG|*&M  
} 0Q^ -d+!  
YY~BNQn6d  
V7}5Zw1  
/* 34ij5bko_)  
**TestMethod.java 3T)GUzt`  
*/ +L(0R&C  
package NetFox; i;4|UeUl  
/[Oo*}Dc=F  
=WFn+#&^  
public class TestMethod { 7?Vo([8  
aChyl;#E  
!QK~l  
public TestMethod() h/u>F$}c  
{ ///xx/weblogic60b2_win.exe d~B]s  
try{ u~MD?!LV  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); f>$Ld1  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); N|cWTbi  
SiteFileFetch fileFetch = new SiteFileFetch(bean);
>_3+s~  
fileFetch.start(); 1<Fh aK  
} hs'J'~a  
catch(Exception e){e.printStackTrace ();}  wfr+-  
g wM~W  
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} 2n}nRv/'  
9GdQ$
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%
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public static void main(String[] args) cR.[4rG'  
{ FwU*]wx|{  
new TestMethod(); gY'w=(/`  
} VO"f=gFg  
} WR'm<u  
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