http断点续传简单实现（java)

/* '_)NI  
**SiteFileFetch.java ub^v,S8O  
*/ fNz*E|]8&  
package NetFox; iwb]mJUA  
import java.io.*; .{6?%lt  
import java.net.*; @o&.]FZs  
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public class SiteFileFetch extends Thread { 4h:R+o ^H^  
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SiteInfoBean siteInfoBean = null; //文件信息Bean nv WTx4oy  
long[] nStartPos; //开始位置 yxfV|ox  
long[] nEndPos; //结束位置 qucw%hJr  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 [5&zyIi  
long nFileLength; //文件长度 s^nPSY!  
boolean bFirst = true; //是否第一次取文件 ,>-Q#  
boolean bStop = false; //停止标志 Zkn$D:
 
File tmpFile; //文件下载的临时信息 ]
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DataOutputStream output; //输出到文件的输出流 <a>\.d9#)7  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） A/kRw'6  
public SiteFileFetch(SiteInfoBean bean) throws IOException w3j51v` 0'  
{ ![O@{/  
siteInfoBean = bean; IEb"tsel  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); K*&?+_v :  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); F^iv1b  
if(tmpFile.exists ()) gemjLuf  
{ RfPRCIo  
bFirst = false; I"*;fdm  
read_nPos(); \<ohe w  
} (`0dO8  
else @d5G\1(%  
{ z?~W]PWiZ  
nStartPos = new long[bean.getNSplitter()]; Iq&S6l <0  
nEndPos = new long[bean.getNSplitter()];
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} =6#tJgg8  
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} Rg*zUfu5%o  
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public void run() ;0}8vs  
{ 'TPRGX~&  
//获得文件长度 ?L|Jc_E  
//分割文件 +cAN4  
//实例FileSplitterFetch T7
W*S-IW  
//启动FileSplitterFetch线程 \Fhk>  
//等待子线程返回 hv xvwV1  
try{ q9n0bw^N  
if(bFirst) 51oZw%os=  
{ &dSw[C#f  
nFileLength = getFileSize(); -
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if(nFileLength == -1) &lYKi3}x  
{ 7#Qa/[? D  
System.err.println("File Length is not known!"); *b"(r|Ko  
} Y=3:Q%X  
else if(nFileLength == -2) ^&t(O1.-  
{ qL^}t_>  
System.err.println("File is not access!"); XezO_V  
} 
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else sV7dgvVd  
{ pk'@!|g%=  
for(int i=0;i<nStartPos.length;i++) ?V_Qa0k  
{ /p') u3  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 3mn0  
} "r0z(j  
for(int i=0;i<nEndPos.length-1;i++) $1(u.Ud  
{ JbYv
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nEndPos = nStartPos[i+1];  l;>#O  
} Yt*M|0bL  
nEndPos[nEndPos.length-1] = nFileLength; "fLGXbNQ  
} GK}?*Lfs  
} 4'rWy~` V  
1W;3pN  
k>{i_`*  
//启动子线程 e4NT  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; |bDN~c:/  
for(int i=0;i<nStartPos.length;i++) bl\44VK2'  
{ 8aGZ% UI  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), >c7/E  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), #RJy  
nStartPos,nEndPos,i); .]ZM2  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); mU_?}}aK,  
fileSplitterFetch.start(); c}mJ6Pt  
} VO(Ck\i}  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), sVkR7 ^KsG  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); %R;cXs4r  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", #`a-b<uz  
nEndPos = " + nFileLength); !N,Z3p>
Q  
// fileSplitterFetch[nPos.length-1].start(); s~/]nz]"J  
[ H>MeeR  
XoSjYG(>,  
//等待子线程结束 ,-CDF)~G=3  
//int count = 0; vyV n5s  
//是否结束while循环 RYE::[O7  
boolean breakWhile = false; &X+V}
 
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EhB9M!Y`@  
while(!bStop) Z/wh?K3y  
{ Dr`\  
write_nPos(); &t%CuU]/@  
Utility.sleep(500); B<1*p,z  
breakWhile = true; `1EBnL_1  
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for(int i=0;i<nStartPos.length;i++) 'n:Ft  
{ %~p_bKd~  
if(!fileSplitterFetch.bDownOver) N/{A' Wd  
{ .F#mT h  
breakWhile = false; Q77
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break; 8kJ k5  
} '0 (Bb  
} v/+dx/  
if(breakWhile) #j-,#P@  
break; ,zXL8T  
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&K>]!yn   
//count++; X""'}X|O  
//if(count>4) oTI*mGR1Z  
// siteStop(); TP{a*ke^5,  
} sxThz7#i)  
i
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System.err.println("文件下载结束！"); tEN]0`  
} mApn(&  
catch(Exception e){e.printStackTrace ();} x(]s#D!)  
} a+{g~/z;,Q  
,xD{A}}V  
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//获得文件长度 {Y/|7Cl0  
public long getFileSize() eU%5CVH.v  
{ u/.srK!K  
int nFileLength = -1; qh7o;x~,  
try{ "[[fQpe4@  
URL url = new URL(siteInfoBean.getSSiteURL()); e982IP  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); nrt0[E-&~  
httpConnection.setRequestProperty("User-Agent","NetFox"); l42m81x"  
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int responseCode=httpConnection.getResponseCode(); /#:RYM'Tu  
if(responseCode>=400) ?G?=,tV  
{ |Y'$+[TE  
processErrorCode(responseCode); K6Gc)jp:b  
return -2; //-2 represent access is error ,6M-xSDs  
} A^K,[8VX  
M%B[>pONb7  
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String sHeader; SAH\'v0  
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for(int i=1;;i++) awkVjyqX  
{ izC>-  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Y43#];  
//Utility.log(in.readLine()); LV]\{'  
sHeader=httpConnection.getHeaderFieldKey(i); mSj
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if(sHeader!=null) mr('zpkRq  
{ (|[3/_!;v  
if(sHeader.equals("Content-Length")) nZ bg  
{ h[Iu_#HMa  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); :.35pp,0  
break; ("lcL2Bq  
} Vbj?:29A  
} PzV(e)~7  
else '
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break; Bw_Ih|y,w  
} &)X<yd0  
} <rC#1wR4  
catch(IOException e){e.printStackTrace ();} 4X\*kF%  
catch(Exception e){e.printStackTrace ();} 
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i*^K)SI8  
Utility.log(nFileLength); vlPE8U=  
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return nFileLength; l?R_wu,Q  
} 0l:5hD,)F  
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+.N;h-
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//保存下载信息（文件指针位置） m
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private void write_nPos() }w-`J5Eq#  
{ >bZ#  
try{ qXhrK /  
output = new DataOutputStream(new FileOutputStream(tmpFile)); OK)0no=OAK  
output.writeInt(nStartPos.length); X,fTzkGj  
for(int i=0;i<nStartPos.length;i++) p|FX_4RjX  
{ kdHql>0  
// output.writeLong(nPos);
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output.writeLong(fileSplitterFetch.nStartPos); <+$S{Z.  
output.writeLong(fileSplitterFetch.nEndPos); `UI)H*GA8  
} > Qtyw.n  
output.close(); .lFSFJ??  
} IRU2/Ycg  
catch(IOException e){e.printStackTrace ();} R/wSGP`W  
catch(Exception e){e.printStackTrace ();} s{,e^T  
} /,>.${,;u  
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//读取保存的下载信息（文件指针位置） ^KaMi_--  
private void read_nPos() Orb(xLChJ  
{ kp6x6%{K\  
try{ M[{Cy[ta  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); IW1\vfe  
int nCount = input.readInt(); P X0#X=$  
nStartPos = new long[nCount]; }dHiW:J>  
nEndPos = new long[nCount];
u#,]>;  
for(int i=0;i<nStartPos.length;i++) 4bBxZY  
{ 9F+bWo_m  
nStartPos = input.readLong(); >ahj|pm  
nEndPos = input.readLong(); j41:]6  
} z K(5&u  
input.close(); "EHc&,B`  
} kb:C>Y8!sC  
catch(IOException e){e.printStackTrace ();} bn`zI~WS  
catch(Exception e){e.printStackTrace ();} RnrM rOh  
} j<KC$[Kt  
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private void processErrorCode(int nErrorCode) Imwx~eo  
{ 8`t%QhE2  
System.err.println("Error Code : " + nErrorCode); ks5'Z8X  
} O9_YVE/-]  
)QE_+H}p  
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//停止文件下载 (J4utw Z  
public void siteStop() %:,=J  
{ gQEV;hCO  
bStop = true; Ueeay^zN  
for(int i=0;i<nStartPos.length;i++) x-pMT3m\D#  
fileSplitterFetch.splitterStop(); |gVO Iq  
^%
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} 2T5xSpC  
} +i^s\c!3;  
//负责部分文件的抓取 f3N:MH-c  
**FileSplitterFetch.java 8Vn6* Xn  
*/ }$)<k
 
package NetFox; *Vl =PNn-  
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import java.io.*; injmP9ed  
import java.net.*; gJ&
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public class FileSplitterFetch extends Thread { 6.|~~/  
LU{Z  
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String sURL; //File URL 8UIL_nPO  
long nStartPos; //File Snippet Start Position =5ih,>>g  
long nEndPos; //File Snippet End Position 4I
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int nThreadID; //Thread's ID //Gvk|O1  
boolean bDownOver = false; //Downing is over Oi0;.<kX  
boolean bStop = false; //Stop identical JY2 F-0t)  
FileAccessI fileAccessI = null; //File Access interface j''Iai_  
?iX=2-  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException \V>%yl{8  
{ 2eU[*x  
this.sURL = sURL; f}X8|GlBo  
this.nStartPos = nStart; m-89nOls  
this.nEndPos = nEnd; 6p"c^  
nThreadID = id; hU 7fZl%yl  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ]M(mq`K  
} sZ"U=6R  
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x+cF1N2.  
public void run() ~vGtNMQg  
{ `z_7[$\~  
while(nStartPos < nEndPos && !bStop) &HK
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{ !C#RW=h9  
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ak) -OL1  
try{ X~he36-+<  
URL url = new URL(sURL); XO#)i6}G  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 9|?Lz  
httpConnection.setRequestProperty("User-Agent","NetFox"); ~(j'a!#Vvk  
String sProperty = "bytes="+nStartPos+"-"; xLI{=sL  
httpConnection.setRequestProperty("RANGE",sProperty); U 0RfovJ  
Utility.log(sProperty); HF: T]n,  
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InputStream input = httpConnection.getInputStream(); DME?kh>7  
//logResponseHead(httpConnection); X-1Vp_(,TP  
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byte[] b = new byte[1024]; Zd U{`>v  
int nRead; 1Wk EPj,  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) \83A|+k  
{ ^|GtO.  
nStartPos += fileAccessI.write(b,0,nRead); \( <{)GpBi  
//if(nThreadID == 1) WcwW@cY7\  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); y8vH?^:%<  
} V;-.38py  
g>xUS_d>  
'$XHRS/q]  
Utility.log("Thread " + nThreadID + " is over!"); R.H\b!  
bDownOver = true; *+j{9LK  
//nPos = fileAccessI.write (b,0,nRead); 2A}uqaF  
} J7ekIQgR  
catch(Exception e){e.printStackTrace ();} SMO%sZ]  
} 
2 dD<]  
} 0?us]lx  
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'UVv(-  
//打印回应的头信息 PdH`_/6  
public void logResponseHead(HttpURLConnection con) "&#WMi  
{ d^5SeCs6  
for(int i=1;;i++) '[ g)v  
{ 8I\eromG  
String header=con.getHeaderFieldKey(i); $U1kP?pR  
if(header!=null) Ws*PMK.0  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); bo;pj$eR3R  
Utility.log(header+" : "+con.getHeaderField(header)); Ccr+SR2  
else oPu|Q^I=  
break; @
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} ~}
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} SxZ^ "\H  
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public void splitterStop() 2^bpH%  
{ NhK(HTsvK  
bStop = true; ,(0XsBL  
} [k~+(.2I  
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=x0"6gTz>  
} !@Sf>DM"  
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/* sRyw\v-=P  
**FileAccess.java sIRrEea  
*//文件访问(定位，写) $',GkK{NX  
package NetFox; Xc2B2c  
import java.io.*; Cre0e$ a  
mU+FQX  
^?
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public class FileAccessI implements Serializable{ 6l\UNG7  
?gR\A8:8  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 nG^M 2)(8  
RandomAccessFile oSavedFile; dI0
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long nPos; [ lzy &To  
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public FileAccessI() throws IOException *lerPY3 q  
{ ^[seK)S=  
this("",0); ^Em@6fz[  
} a4jnu:e  
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public FileAccessI(String sName,long nPos) throws IOException 9O=05CQ  
{ T]nR=uK6LL  
oSavedFile = new RandomAccessFile(sName,"rw"); f_4S>C$  
this.nPos = nPos; hdf8U  
oSavedFile.seek(nPos); eY4
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} SfZ=%6b7  
!HR2Rfl  
Q}Ze-JIL$  
public synchronized int write(byte[] b,int nStart,int nLen) XJJ[F|k~  
{ V"7<[u]K|  
int n = -1; {FJX  
try{ M8?#%x6;N  
oSavedFile.write(b,nStart,nLen); urrO1  
n = nLen; u_
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} ?b@q5Y  
catch(IOException e) *H%0Gsk  
{ 6>=-/)p}  
e.printStackTrace (); $ o5V$N D  
} T^'*_*m  
 ?+ -/';  
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return n; oBRm\8 2|  
} 8tV=fSHd  
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} #0?"J)  
8g[(nxI~  
Ho)t=qn  
/* &N/|(<CB  
**SiteInfoBean.java ~^rey  
*/ 'z +$3\5L  
package NetFox; >?>ubM`,  
8Fd1;G6  
N;C"X4rV  
public class SiteInfoBean { @Z9>3'2]A  
PG^j}  
&?/N}g@K  
private String sSiteURL; //Site's URL %Ye)8+-  
private String sFilePath; //Saved File's Path b:FEp'ZS  
private String sFileName; //Saved File's Name ot@|blVC8  
private int nSplitter; //Count of Splited Downloading File 3@PUg(M  
+p9LE4g7Q  
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G  
public SiteInfoBean() a%Z4_ToLZ  
{//nSplitter的缺省值为5 IS,zy+w  
//default value of nSplitter is 5 DnNt@e2|  
this("","","",5); j}rgO
z.  
} XlPK3^'N)h  
4;BW  
@4/~~  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) zj~nnfoys  
{ i
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sSiteURL= sURL; VM-qVd-  
sFilePath = sPath; _=|nOj39  
sFileName = sName; _l24Ba$F6  
this.nSplitter = nSpiltter; L _vblUDq  
Vqa5RVnI  
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} >W`S(a Mn  
6CcB-@n4  
'[>\N4WD  
public String getSSiteURL() )myf)"l5  
{ l-<3{!  
return sSiteURL; 22)0zY%\  
} D'7A2f  
.mvB99P{<  
x[vpoB+c  
public void setSSiteURL(String value) g(-;_j!=  
{ Ci]'G>F@"  
sSiteURL = value; tMxsR>sH  
} F5FNhuC  
=oo[ Eyr  
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public String getSFilePath() tt+>8rxF:;  
{ .abyYVrN4?  
return sFilePath; /hm84La  
} u:_sTfKm&  
[NHg&R H  
Mam8\  
public void setSFilePath(String value) OD  
{ vC{h2A  
sFilePath = value; \ V[;t-  
} t2=a(N-/,  
p//T7rs  
a$C2}  
public String getSFileName() Ho|o,XvLv  
{ %*$5!;  
return sFileName; {V}t'x`4c  
} y=[gQJ6~r  
lq:]`l,6@  
Sp 7u_Pq{  
public void setSFileName(String value) c:=7lI  
{ `%$8cZ-kr  
sFileName = value; 8h*t55  
} E)C.eW /  
~
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yOX&cZ[  
public int getNSplitter() %9t{Z1$  
{ {I4%  
return nSplitter; @)o0GHNP  
} rpUy$qrRc  
j_!bT!8  
}TSgAwsbC  
public void setNSplitter(int nCount) MVeFe\r  
{ F(d:t!  
nSplitter = nCount; PXV)NC  
} ETM2p1ru0  
} K@q&HV"'.  
qOW#Q:T  
t
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/* A[RHw<  
**Utility.java GHv{   
*/ Vd,' s  
package NetFox; 7e1dEgn  
z<a$q3!#  
i*X{^A73"  
public class Utility { Y^QKp"  
DH:J  
E[S? b=^  
public Utility() },ra
v]  
{ v9u<F6  
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w"{bp  
} &B}Lo  
>L^xlm%7o  
//线程睡眠 <x0)7xX  
public static void sleep(int nSecond) tE[H8  
{ 4avc=Y5  
try{ :-)GNf yGz  
Thread.sleep(nSecond); uM<|@`&b  
} O#vn)+Y,*  
catch(Exception e) q%>7L<r  
{ ZI,j?i6\  
e.printStackTrace (); tmp6hB  
} bMsECA&  
} cg,Ua!c  
 @@Q6TB  
//日志 [q1Unm  
public static void log(String sMsg) }g>kpa0c  
{ Y=E9zUF  
System.err.println(sMsg); Rv,82iEKs  
} f27)v(EJ  
k=?^){[We  
Jn=42Q:>  
public static void log(int sMsg) mwIk^Sz]@  
{ UgR:qjI  
System.err.println(sMsg); _5b0wdB  
} q]TqI' o  
} bw9 nB{C<  
]BfS270  
J_PH7Z*=,  
/* E tx`K5Tr]  
**TestMethod.java #1[z;Mk0  
*/ *<IR9.~{6%  
package NetFox; X]!D;7^  
i E9\_MA  
m<{"}4'  
public class TestMethod { KnJx{8@z  
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.#0H{m
k  
public TestMethod() xdZ<| vMR  
{ ///xx/weblogic60b2_win.exe mZ7B<F[qV  
try{ 3V}(fnv  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); $eBQH  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); v5T`K=qC  
SiteFileFetch fileFetch = new SiteFileFetch(bean); \,R!S/R#  
fileFetch.start(); ]v\^&7pW  
} Yl~$V(  
catch(Exception e){e.printStackTrace ();} o\4CoeG  
)t%h[0{{  
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} oxfF`L"  
 <B)   
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public static void main(String[] args) zb:kanb-  
{ =We2^W-{
 
new TestMethod(); hm\\'_u  
} qfYG.~`5  
} w{`Acu  
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