http断点续传简单实现（java)

/*
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**SiteFileFetch.java 7nT|yL?  
*/ $=.%IJ_MAz  
package NetFox; T{ @@
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import java.io.*; .L^*9Y0)  
import java.net.*; WkiT,(i  
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public class SiteFileFetch extends Thread {  lPZ>#  
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SiteInfoBean siteInfoBean = null; //文件信息Bean a"-uJn  
long[] nStartPos; //开始位置 `"65 _?B i  
long[] nEndPos; //结束位置 ^"7-`<J  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 8p 4[:M@  
long nFileLength; //文件长度 1*p6UR&  
boolean bFirst = true; //是否第一次取文件 = zmxki  
boolean bStop = false; //停止标志 >fYcr#i0[  
File tmpFile; //文件下载的临时信息 $\ZWQct  
DataOutputStream output; //输出到文件的输出流 fJ8>nOh  
Q`*U U82!  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） <5G(Y#s/?  
public SiteFileFetch(SiteInfoBean bean) throws IOException )f$4:Pq  
{ L6CI9C;-b  
siteInfoBean = bean; bIGcszWr  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); -m}'I8  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); [RKk-8I  
if(tmpFile.exists ()) ufk2zL8y  
{ = vqJ0!  
bFirst = false; b4L7]&  
read_nPos(); !AXLoq$SY  
} oIO@#   
else 0JtM|Mg  
{ DU6j0lz  
nStartPos = new long[bean.getNSplitter()]; .bY>++CAPA  
nEndPos = new long[bean.getNSplitter()]; vQCb?+X&  
} I8!>7`L  
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} 9_wDh0b~p  
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public void run() zV}:~;w  
{ ~E6sY  
//获得文件长度 eikZ~!@  
//分割文件 eW 4[2Q  
//实例FileSplitterFetch 60|PVsmDm  
//启动FileSplitterFetch线程 .<?7c!ho  
//等待子线程返回 ;@S'8  
try{ |9XoRGgXU  
if(bFirst)
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{ e'uC:O.u  
nFileLength = getFileSize(); ]*=!lfrV  
if(nFileLength == -1) KH
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{ ?ja%*0 R  
System.err.println("File Length is not known!"); o*A, 6y  
} U+'zz#0qN  
else if(nFileLength == -2) 0
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{ Wi=zu[[qc  
System.err.println("File is not access!"); K/B$1+O  
} [_%u5sc-y  
else X~&8^?  
{ Vj4 h#NN$  
for(int i=0;i<nStartPos.length;i++) 564L.^$@|  
{ Jf4` 2KN\  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); q`PA~C];  
} 1|8Bv0-b  
for(int i=0;i<nEndPos.length-1;i++) b;D  
{ 7yu-xnt3s  
nEndPos = nStartPos[i+1]; B?&0NpVD  
} W#!AZ!  
nEndPos[nEndPos.length-1] = nFileLength; WYF8?1dt +  
} w/ ~\NI  
} ;+C$EJw-  
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>"IG\//I  
//启动子线程 \},H\kK+^  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; -3yK>\y=|  
for(int i=0;i<nStartPos.length;i++) 5ph CEKt;  
{ rZwSo]gp  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), (z8ZCyq7r[  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), vcj(=\ e8v  
nStartPos,nEndPos,i); !i8)si_  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 
41=H&G&  
fileSplitterFetch.start(); %r.OV_04  
} &I=o1F2B)  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), i/*)1;xsk  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); dH5*%  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", hN K wQ  
nEndPos = " + nFileLength); <gi~:%T  
// fileSplitterFetch[nPos.length-1].start(); :Ni#XZ{F-/  
cQ<|Of  
9Vq  
//等待子线程结束 ;UXV!8SM  
//int count = 0; h8O\sKn  
//是否结束while循环 u(3 u
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boolean breakWhile = false; XK\n
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while(!bStop) >Z*b0j  
{ ZDaHR-%Y  
write_nPos(); d)U(XiK'  
Utility.sleep(500); | eCVq(R  
breakWhile = true; s%y<FXUj  
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for(int i=0;i<nStartPos.length;i++) X
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{ (PH7nW7  
if(!fileSplitterFetch.bDownOver) W=EcbH9/.)  
{ 5Q%)|(U'  
breakWhile = false; _)<5c!  
break; uQbag]&j  
} ;;i419  
} m$W2E.-$'#  
if(breakWhile) DM v;\E~D  
break; zmZU"eWp)  
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//count++; +JG05h%'  
//if(count>4) k@%5P-e}  
// siteStop(); $-]G6r  
} .9Oj+:n  
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 nm`(;<W  
System.err.println("文件下载结束！"); %JPr 7 }  
} hj"JmF$m  
catch(Exception e){e.printStackTrace ();} kD+#|f  
} Zs}h>$E5_B  
PW%ith1)<  
-*[)CR-{  
//获得文件长度 y|BHSc3  
public long getFileSize() uPcx6X3]  
{ p q?# X0  
int nFileLength = -1; yqK_|7I+  
try{ $X:,Q,?  
URL url = new URL(siteInfoBean.getSSiteURL()); EP;ts  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); c{to9Lk.#  
httpConnection.setRequestProperty("User-Agent","NetFox"); Cp!9 "J:  
~)$R'=  
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int responseCode=httpConnection.getResponseCode(); &FRf-6/  
if(responseCode>=400) }8l+Jd3"  
{ 0Y* "RbG  
processErrorCode(responseCode); |UlR+'rl  
return -2; //-2 represent access is error /
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} c99|+i
50  
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String sHeader; _&q&ID  
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for(int i=1;;i++) lMW6D0^  
{ ?$;&DoE  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 8hy1yt6t4~  
//Utility.log(in.readLine()); HQ=pf >  
sHeader=httpConnection.getHeaderFieldKey(i); COWlsca  
if(sHeader!=null) xzz@Wc^_  
{ M@q)\UQ'  
if(sHeader.equals("Content-Length")) $A74V[1^  
{ kz1Z K  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); i)cG  
break; n&]J-^Tx  
} Z>w@3$\z  
} :-+][ [  
else _}\KC+n8  
break; q4@+Pi)  
} Bk.`G)t  
} l0yflF
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catch(IOException e){e.printStackTrace ();} y#Nrq9r:  
catch(Exception e){e.printStackTrace ();} S]T71W<i  
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Utility.log(nFileLength); H.n|zGQTB  
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{ ~{D(k  
return nFileLength; V^D1:9i  
} xPT$d,~"  
n|=yw6aV'  
b!SIs*  
//保存下载信息（文件指针位置） "/^kFsvp  
private void write_nPos() s#0m  
{ j;Lp@~M  
try{ biV|W@JM  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 26zif
  
output.writeInt(nStartPos.length); uGl
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for(int i=0;i<nStartPos.length;i++) M>RLS/r>d  
{ 23;\l   
// output.writeLong(nPos); eon(C|S7eK  
output.writeLong(fileSplitterFetch.nStartPos); Z^A(Q>{e  
output.writeLong(fileSplitterFetch.nEndPos); }EfRYE$E  
} ou|3%&*"  
output.close(); b[n6L5P5m2  
} @ohJ'
 
catch(IOException e){e.printStackTrace ();} '@hnqcqXq  
catch(Exception e){e.printStackTrace ();} A-\n"}4  
} y fS  
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//读取保存的下载信息（文件指针位置） Oh`Pf;.z%  
private void read_nPos() z;YX2G/{  
{ 2j>C4Ck  
try{ hoPh#? G  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); .b*-GWx  
int nCount = input.readInt(); 0B`rTLwB  
nStartPos = new long[nCount]; _#P5j#  
nEndPos = new long[nCount]; eBECY(QMQ  
for(int i=0;i<nStartPos.length;i++) CS"k0V44}  
{ 1*@Q~f:Uk  
nStartPos = input.readLong(); G in  
nEndPos = input.readLong(); \=W t{  
} :e_yOT}}  
input.close(); lQ.3_{"s  
} Si#XF[/  
catch(IOException e){e.printStackTrace ();} _{i-.
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catch(Exception e){e.printStackTrace ();} 99q$>nx,w  
} ^&c|z35F  
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private void processErrorCode(int nErrorCode) ol4!#4Y&{  
{ $/JnYkL{m  
System.err.println("Error Code : " + nErrorCode); oB}rd9  
} \H
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4~:D7",Jn  
//停止文件下载 s.}:!fBk  
public void siteStop() ~]K<Vh`  
{ 7XIG ne%v  
bStop = true; /z,+W9`  
for(int i=0;i<nStartPos.length;i++) M^A;tPw  
fileSplitterFetch.splitterStop(); Q
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} l>>,~  
} @2$iFZq~  
//负责部分文件的抓取 U./1OZ&  
**FileSplitterFetch.java %eqL)pC]  
*/ }5;3c%  
package NetFox; J&b&*3   
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oakm{I|k}  
import java.io.*; +@oo8io  
import java.net.*; Uefw  
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public class FileSplitterFetch extends Thread { ;,_c1x/F  
?jBh=X\]:  
! XNTk]!  
String sURL; //File URL 9o5_QnGE  
long nStartPos; //File Snippet Start Position le`_  
long nEndPos; //File Snippet End Position gI~jf- w  
int nThreadID; //Thread's ID G9\@&=  
boolean bDownOver = false; //Downing is over lhV'Q]s@6  
boolean bStop = false; //Stop identical &5wM`  
FileAccessI fileAccessI = null; //File Access interface R_DZJV O  
oG;;='*  
%8GY`T:^  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException s%qK<U4@;Q  
{ ut^^,w{o>  
this.sURL = sURL; ViT$]Nv  
this.nStartPos = nStart; VlFDMw.4.+  
this.nEndPos = nEnd; QI2T G,  
nThreadID = id; Bx&wS|-)D  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 D3%`vqu&  
} vo DTU]pf  
.!J,9PE  
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public void run() n
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{
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while(nStartPos < nEndPos && !bStop) ;yH1vX  
{ |LDo<pE*V4  
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try{ XmoS$/#"  
URL url = new URL(sURL); %sLij*  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); H0B"?81  
httpConnection.setRequestProperty("User-Agent","NetFox"); o93A:fc  
String sProperty = "bytes="+nStartPos+"-"; _7zER6#}  
httpConnection.setRequestProperty("RANGE",sProperty); 4 p(KdYc  
Utility.log(sProperty); 
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M
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InputStream input = httpConnection.getInputStream(); ^m:?6y_uw  
//logResponseHead(httpConnection); 0TI+6u  
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8^N"D7{mO  
byte[] b = new byte[1024]; l0$ +)FKd  
int nRead; 3E361?ubM  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Z*|qbu)  
{ ;2;Kq)j_=  
nStartPos += fileAccessI.write(b,0,nRead); ' RjFWHAp  
//if(nThreadID == 1) :bgi*pR{  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); WV"{oED  
} yVM 1W"Q  
29#;;n}p  
@kLpK  
Utility.log("Thread " + nThreadID + " is over!"); ?9801Da#/  
bDownOver = true; `jb?6;15  
//nPos = fileAccessI.write (b,0,nRead); r`L$[C5I  
} <vV?VV([  
catch(Exception e){e.printStackTrace ();} Ot]P
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} vF K&.J
 
} b&Sk./ J6  
NY ZPh%x  
89'XOX
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//打印回应的头信息 )S|}de/a2  
public void logResponseHead(HttpURLConnection con) bewi.$E{  
{ 1qb
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for(int i=1;;i++) F3b[L^Km]  
{ Bk1Q.Un  
String header=con.getHeaderFieldKey(i); .Go3'$'v  
if(header!=null) 9)QvJ87e@7  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); V<@]Iv  
Utility.log(header+" : "+con.getHeaderField(header)); |:tFQ.Z'2  
else h2Z Gh  
break; iCIu]6  
} f[!QR  
} @&]j[if(s  
C/+8lA6NV  
?K/z`E!xhN  
public void splitterStop() W<3nF5!  
{ 3L4lk8Dd  
bStop = true; #{l+I(M  
} ?'h<yxu]u0  
qf9.S)H1Z  
!_cT_ WHty  
} mIZ#uW  
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/* XH0R:+s  
**FileAccess.java ?/~7\ '|Z  
*//文件访问(定位，写) xU^Flw,4  
package NetFox; uM0z%z5b  
import java.io.*; F[c;iM(^  
g/4.^c  
d3(T=9;f2  
public class FileAccessI implements Serializable{ lFD$Mc  
oZ@_o3VG  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 !+T+BFw.  
RandomAccessFile oSavedFile; %?C{0(Z{  
long nPos; gRKmfJ*u  
+MeEy{;  
pscCXk(|A`  
public FileAccessI() throws IOException 0%+TU4Xx  
{ Xt/muV  
this("",0); <vA^%D<\~  
} hsljJvs
 
}$;T.[ ~  
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public FileAccessI(String sName,long nPos) throws IOException \sF}NBNT@  
{ c% 0h!zF  
oSavedFile = new RandomAccessFile(sName,"rw"); {JzX`Z30l  
this.nPos = nPos; 8Hs>+Udl  
oSavedFile.seek(nPos); Y'Jb@l`$-  
} ^^%sPtp  
~^IS{
1  
VD.p"F(]  
public synchronized int write(byte[] b,int nStart,int nLen) !w98[BE7  
{ +tOBt("5/  
int n = -1; s%J|r{F6  
try{ abCcZ<=|b  
oSavedFile.write(b,nStart,nLen); X1i6CEa<  
n = nLen; :*6tbUp  
} l<{]%=Qg  
catch(IOException e) xZL`<3?  
{ Ps.O.2Z5ZB  
e.printStackTrace (); SA{A E9y  
} 'e\m6~u\hm  
t[
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return n; yGH'|`  
} ZqkP# ]+Y'  
^Y~ ,s  
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} o'%F*>#v  
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#* 
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/* )AqM?FE4R  
**SiteInfoBean.java
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*/ VE6T&fz`  
package NetFox; yK0Q,   
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D_9&=aa'  
public class SiteInfoBean { =6j  5,  
<Ky\^  
I1&Z@[  
private String sSiteURL; //Site's URL o~gduNG#  
private String sFilePath; //Saved File's Path KcfW+>W3  
private String sFileName; //Saved File's Name )~O{jd  
private int nSplitter; //Count of Splited Downloading File wQp,RpM  
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av gGz8  
public SiteInfoBean() V_~}7~ I  
{//nSplitter的缺省值为5 '9*wr*  
//default value of nSplitter is 5 W2yNEiH  
this("","","",5); ~5`rv1$  
} g 6>RyjN  
}`IN5NdYp  
c$?qN&X_K  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) eP'e_E  
{ ]NuY{T&:  
sSiteURL= sURL; 2#*Bw=  
sFilePath = sPath; *2 4P T7  
sFileName = sName; aAwnkQ$  
this.nSplitter = nSpiltter; >('L2]4\v  
c"H4/,F  
GfJm&'U&  
} 0X0HDQ  
&EXql']  
WaN0$66[:  
public String getSSiteURL() d<V+;"
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{ "
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return sSiteURL; 23pHB
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} 1b;Aru~l  
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0UWLs_k:  
public void setSSiteURL(String value) W}WGg|ug  
{ )+oDa{dZ  
sSiteURL = value; !;'U5[}8  
} EZIMp8^  
jLD=EJ  
{NKDmeg:D  
public String getSFilePath() /.$n>:XR  
{ 6O$OM  
return sFilePath; -YA1Uk  
} X LA  
uMP
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public void setSFilePath(String value) `8xe2
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{ %=S^{
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sFilePath = value; ;r^8In@6  
} 6g@j,iFy  
:5U(}\dL{  
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public String getSFileName() h 
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{ 3UD_2[aqN(  
return sFileName; f Nm Sx  
} e0j*e7$  
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public void setSFileName(String value) BA A)IQF  
{ }n:'@}  
sFileName = value; UG&/0{j5XV  
} G}BO!Z6  
Tp)-L0kD_k  
f*1.Vg0`-  
public int getNSplitter() 2ztP'  
{ bzk@6jR1  
return nSplitter; 1xL2f&bG  
} RQ9fA1YP  
?%;7k'0"  
%Ni)^   
public void setNSplitter(int nCount) i?qS8h{  
{ 9d#-;qV  
nSplitter = nCount; Gow_
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} *vCJTz  
} E:&=A 4%  
.FqbX5\p,  
!wJ~p:vRdY  
/* 2[r#y1ro  
**Utility.java k U*
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*/ d=xU f`^  
package NetFox; O6Xu/X]  
8g(%6 ET  
d01bt$8>  
public class Utility { 4@/
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h[ba$S,T  
(gvaYKvr  
public Utility() eMPi ho  
{ xo6-Y=c8  
k~`pV/6  
`L]cJ0tAs  
} rzLpVpTaz  
Y71io^td~j  
//线程睡眠 *]W{83rXQ  
public static void sleep(int nSecond) w/~,mzM"  
{ #If}P$!  
try{ dF5EIPl;J  
Thread.sleep(nSecond); TW{.qed8^  
} BV9B}IV  
catch(Exception e) ?\(E+6tpP  
{ jXSo{  
e.printStackTrace (); &}OaiTzEmc  
} )
f*&}SV  
} uPr@xff  
+a"MSPC4w  
//日志 x`WP*a7Fk]  
public static void log(String sMsg) x: `oqbd  
{ 9K@`n:Rw  
System.err.println(sMsg); +Z/*=;  
} Cc$!TZq=  
{tOu+zy  
R',Q)<  
public static void log(int sMsg) ,=Xr'7w,  
{ *6df|q  
System.err.println(sMsg); yS@c2I602  
} q$(aMO&J  
} k9~NIvnB`  
!L2R0Y:a  
L1VUfEG-  
/* Ha[Bf*  
**TestMethod.java brl(7_2  
*/ r0+lH:G*q  
package NetFox; g`d5OHvOo  
; "ux{ .  
=;l.<{<VH  
public class TestMethod { A Ns.`S  
4fT,/[k?  
CJ8XKy  
public TestMethod() #@w8wCj  
{ ///xx/weblogic60b2_win.exe +j1s*}8  
try{ VY<$~9a&1  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 58DkVQ6  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ?S~HnIn  
SiteFileFetch fileFetch = new SiteFileFetch(bean); dPc*!xrq  
fileFetch.start(); %nSm 32/t3  
} r?nvJHP  
catch(Exception e){e.printStackTrace ();} @mSdksB/L  
X#EMmB!  
ONH!ms(kb  
} AME3hA  
)^qM%k8  
yAy~|1}  
public static void main(String[] args) 9y{[@KG  
{ =3]}87  
new TestMethod(); F=7X,hK  
} 6NPCp/  
} MCZTeYnx  
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