http断点续传简单实现（java)

/* d=vD Pf  
**SiteFileFetch.java ,_7m<(/f  
*/ &DtI+)[|  
package NetFox; D"fjk1  
import java.io.*; k{Y\YG%b  
import java.net.*; $OGMw+$C^  
@#o7U   
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public class SiteFileFetch extends Thread { 1UrkDz?X  
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SiteInfoBean siteInfoBean = null; //文件信息Bean oz3!%'  
long[] nStartPos; //开始位置 l% %cU"  
long[] nEndPos; //结束位置 7:$dl#  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 4RQ38%> >j  
long nFileLength; //文件长度 3|3ad'  
boolean bFirst = true; //是否第一次取文件 B<@a&QBTg  
boolean bStop = false; //停止标志 MScUrW!TA  
File tmpFile; //文件下载的临时信息 v33[Rk'
 
DataOutputStream output; //输出到文件的输出流 ?"}U?m=  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） wt_ae|hv  
public SiteFileFetch(SiteInfoBean bean) throws IOException ">fRM=fl  
{ chuJj IY  
siteInfoBean = bean; n*|8(fD  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 1T,Bd!g  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); %>O}bdSf  
if(tmpFile.exists ()) GV9pet89yu  
{ [>j.x2=  
bFirst = false; bgInIe
 
read_nPos(); Ia^/^>  
} )J[Ady^5  
else .'-t>(}v  
{ vKkvB;F41  
nStartPos = new long[bean.getNSplitter()]; [c=![*}/  
nEndPos = new long[bean.getNSplitter()]; b4ke'gx  
} P=9sP:[f6  
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} `I|Y7GoUO  
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public void run() $K|2k7  
{ A>:31C  
//获得文件长度 {+9t!'   
//分割文件 "JYWsE  
//实例FileSplitterFetch :c[T@[  
//启动FileSplitterFetch线程 ')fIa2dO/  
//等待子线程返回 dsK^-e6:5  
try{ pG/g  
if(bFirst) O=1#KNS  
{ aJ]t1  
nFileLength = getFileSize(); ^#7&R"  
if(nFileLength == -1) q| *nd!y'  
{ ]zvOM^l~  
System.err.println("File Length is not known!"); T?-K}PUcQ  
} 7tY~8gQel  
else if(nFileLength == -2) itO1ROmu  
{ sQT,@+JEr  
System.err.println("File is not access!"); %Si3LQf  
} Q6[h;lzGV  
else _9/Af1X  
{ Z>'hNj)ju  
for(int i=0;i<nStartPos.length;i++) MB.LHIo  
{ DsBZ%  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); t{ridA}  
} !6s]p%{V  
for(int i=0;i<nEndPos.length-1;i++) !<>`G0  
{ qMBEJ<o  
nEndPos = nStartPos[i+1]; \5) ZI'q  
} xz/G$7q7  
nEndPos[nEndPos.length-1] = nFileLength; mj2sbRiSR=  
} Nn5sD3z#  
} Oo%%f+  
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kr]_?B(r  
//启动子线程 YdAC<,e&A  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; fhQ N;7  
for(int i=0;i<nStartPos.length;i++) -]MZP:s  
{ `[f IK,  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 8O^z{Yh7  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), }GGH:v
 
nStartPos,nEndPos,i); r
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Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); OgyHX>}bH  
fileSplitterFetch.start(); D_I_=0qNd  
} 8GT{vW9  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 7I6&*I  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); pkA(\0E8  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", tpKQ$)ed  
nEndPos = " + nFileLength); <UJ5n) }"\  
// fileSplitterFetch[nPos.length-1].start(); &)Iue<&2  
5kj=Y]9\I  
{E>(%vD  
//等待子线程结束 :UsNiR=l  
//int count = 0; 8DlRD$_:&  
//是否结束while循环 of.=n  
boolean breakWhile = false; }j#c#''i  
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UrB{jS?  
while(!bStop) 5CM]-qbf@  
{ Cx`?}A\%  
write_nPos(); &e
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Utility.sleep(500); }Q>??~mVl
 
breakWhile = true; 3ry0.  
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for(int i=0;i<nStartPos.length;i++) )G9,5[  
{ 9=MxuBl  
if(!fileSplitterFetch.bDownOver) @1 )][r-7  
{ j}DG +M  
breakWhile = false; ?|we.{  
break; -B#>Jn#F  
} V8J!8=2  
} kR(hUc1O  
if(breakWhile) >1d`G%KfG  
break; SNf*2~uq)  
PF/eQZ*4  
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//count++; ~G`(=\_0  
//if(count>4) ]1n =O"vE  
// siteStop(); ^Zw1X6C5~  
} S4(lC%$|  
3+$~l5LY  
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System.err.println("文件下载结束！"); GbZqLZ0  
} q%GlS=o"  
catch(Exception e){e.printStackTrace ();} FOd)zU*L2  
} Ny)!uqul*  
veh?oJi@  
2AI~Jm#  
//获得文件长度 VE5M}kDCZ  
public long getFileSize() Ce1^S[
 
{ k9?fE  
int nFileLength = -1; ue{0X\[P<  
try{ 8!{F6DG  
URL url = new URL(siteInfoBean.getSSiteURL()); re\&'%~K  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); elf2!  
httpConnection.setRequestProperty("User-Agent","NetFox"); o72G oUfs  
7nAB^~)6l  
7ClN-/4  
int responseCode=httpConnection.getResponseCode(); !r*Ogv[  
if(responseCode>=400) YYUWBnf30G  
{ V8.o}
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processErrorCode(responseCode); ;y"quJ'O  
return -2; //-2 represent access is error A296f(  
} VdV18-ea  
>|22%YVX  
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String sHeader; eE/E#W8  
}<hyW9  
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for(int i=1;;i++) z tLP {q#  
{ 4=E9$.3a  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); SiyZq"  
//Utility.log(in.readLine()); 'X
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sHeader=httpConnection.getHeaderFieldKey(i); UfnjhHu  
if(sHeader!=null) HqpwQ  
{ BHh%3Q  
if(sHeader.equals("Content-Length")) {m/h3hjFa  
{ ]N+(SU  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); WM_wkvYl  
break; ,KHebv!  
} \]eB(&nq  
} OZ6gu$ n*  
else B2PjS1z2  
break; HG/`5$L +}  
} S~mpXH@  
} )ieT/0nt  
catch(IOException e){e.printStackTrace ();} W7QcDR y6  
catch(Exception e){e.printStackTrace ();} 2Po e-=  
" E U[Lb  
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Utility.log(nFileLength); QFm~wv8:  
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return nFileLength; b]Xc5Dp{  
} ,dM}B-  
{ ke}W  
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//保存下载信息（文件指针位置） @3hA\3ot^  
private void write_nPos() pPNU0]/  
{ Q^qdm5}UkW  
try{ R
7)2@;i  
output = new DataOutputStream(new FileOutputStream(tmpFile)); PO,mg?JG(  
output.writeInt(nStartPos.length); m4.IaBn/  
for(int i=0;i<nStartPos.length;i++) kCWaji_x%  
{ <TL!iM  
// output.writeLong(nPos); l H@hV  
output.writeLong(fileSplitterFetch.nStartPos); J~3+j6?%  
output.writeLong(fileSplitterFetch.nEndPos); 6 ZutU ~HS  
} /K{`gc  
output.close(); FCu0)\  
} )!:}R}q  
catch(IOException e){e.printStackTrace ();} 7n,*3;I  
catch(Exception e){e.printStackTrace ();} Vnu*+  
} #3l&N4/  
j~d<n_   
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//读取保存的下载信息（文件指针位置） y3 v
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private void read_nPos() +O 2H":$  
{ _<`j?$P  
try{ t7"vAjZU  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Uk=-A @q  
int nCount = input.readInt(); f,'gQ5\ X3  
nStartPos = new long[nCount]; brk>oM;t  
nEndPos = new long[nCount]; X
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for(int i=0;i<nStartPos.length;i++) 2nL[P#r  
{ .]_ (>^6  
nStartPos = input.readLong(); FvpI\%#~  
nEndPos = input.readLong();  0(2r"Hi  
} 9%i|_c}  
input.close(); p,hDZea  
} xWv@PqXD  
catch(IOException e){e.printStackTrace ();} WQ(*
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catch(Exception e){e.printStackTrace ();} dvWQ?1l_  
} T(UPWsj  
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private void processErrorCode(int nErrorCode) a9hK8e  
{ &&/2oP+z  
System.err.println("Error Code : " + nErrorCode); @j/UDM  
} :`~;~g
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k?%?EsR  
^h}xFiAV#  
//停止文件下载 bG`aF*10)!  
public void siteStop() dWhki|c  
{ 9"5J-a'  
bStop = true; ev}lb+pr)_  
for(int i=0;i<nStartPos.length;i++) uAd4Zz  
fileSplitterFetch.splitterStop(); z@Klj qN  
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} To_Y 8 G  
} HzcI2 P`|  
//负责部分文件的抓取 gVM&wo |  
**FileSplitterFetch.java t u)kWDk  
*/ Rt &Oz!TQ  
package NetFox; 8reis1]2S  
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import java.io.*; R4 8w\?L  
import java.net.*; \yIan<q  
jF5Y-CX  
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public class FileSplitterFetch extends Thread { (%&HufT  
v{/z`J!JR  
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String sURL; //File URL C5q n(tv  
long nStartPos; //File Snippet Start Position o5NV4=  
long nEndPos; //File Snippet End Position F}/tV7m  
int nThreadID; //Thread's ID =Oo=&vA.oc  
boolean bDownOver = false; //Downing is over 6Qo YX] .  
boolean bStop = false; //Stop identical Q{s9{  
FileAccessI fileAccessI = null; //File Access interface fwe4f  
>l<`)4*H  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 3#O Rfr(  
{ UcZ20inj0  
this.sURL = sURL; T1\LS*~!  
this.nStartPos = nStart; !
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this.nEndPos = nEnd; p$mx  
nThreadID = id; sqtMhUQ?>w  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 q%g!TFMg  
} v}vwk8  
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public void run() 8`QbUQ6  
{ xSnkv,my<  
while(nStartPos < nEndPos && !bStop)
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{ P2U^%_~  
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try{ fi|k)  
URL url = new URL(sURL); {5%u G2g  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); FX"j8i/N  
httpConnection.setRequestProperty("User-Agent","NetFox"); V7+fNr]I  
String sProperty = "bytes="+nStartPos+"-"; Pv- i.  
httpConnection.setRequestProperty("RANGE",sProperty); reBAxmt   
Utility.log(sProperty); ~pv|  
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InputStream input = httpConnection.getInputStream(); [&Yrnkgr  
//logResponseHead(httpConnection); IE^xk@  
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|`N|S  
byte[] b = new byte[1024]; "s$$M\)T  
int nRead; thT2U8%T  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) $,@PY5r  
{ DW@|H  
nStartPos += fileAccessI.write(b,0,nRead);

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//if(nThreadID == 1)  ;r
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// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); xaPaK-  
} L
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`>i8$q%  
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Utility.log("Thread " + nThreadID + " is over!"); !HV<2q()  
bDownOver = true; ZOAHM1ci  
//nPos = fileAccessI.write (b,0,nRead); J~}%j.QQ7  
} |\#~  
catch(Exception e){e.printStackTrace ();} jpGZ&L7i&  
} F,[GdE;P  
} C\3;o]  
&U
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|TQ#[9C0  
//打印回应的头信息 0~/'c0Ho  
public void logResponseHead(HttpURLConnection con) 3A`|$So  
{ sz"N,-<Ig  
for(int i=1;;i++) qKSS 2f $  
{ O`M6=\  
String header=con.getHeaderFieldKey(i); [3@Pu.-I+M  
if(header!=null) eYpK!9
 
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Z,jR:_p  
Utility.log(header+" : "+con.getHeaderField(header)); efT@A}sV  
else _~Q
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break; K*QRi/O  
} QWncKE,O$  
} y
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(9]8r2|.  

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public void splitterStop() F|wT']1Y  
{ _HAtTW  
bStop = true; `K%f"by  
} a'Vz|SG  
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} ^oLMgz  
at 
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/* ;%ng])w=;  
**FileAccess.java 6?BV J  
*//文件访问(定位，写) ~L
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package NetFox; @'~7O4WH  
import java.io.*; +{r~-Rn3  
_k|k$qxE  
?niv}/'%O  
public class FileAccessI implements Serializable{ ns&3Dh(IVP  
x@p1(V.  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 aA6m5  
RandomAccessFile oSavedFile; 75"&"*R/*G  
long nPos; >53Hqzm&  
;"9$LHH*  
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public FileAccessI() throws IOException B<Zm'hdX  
{ F*Y]^9]  
this("",0); -T8'|"g  
} 0^25uAD=  
_kZ&t_]  
,Qh9}I7;C  
public FileAccessI(String sName,long nPos) throws IOException .3 S9=d?  
{ <
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oSavedFile = new RandomAccessFile(sName,"rw"); Nf^6t1se  
this.nPos = nPos; 1)BIh~1{p  
oSavedFile.seek(nPos); N|3a(mtiZ'  
} DUMC4+i  
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public synchronized int write(byte[] b,int nStart,int nLen) j9r%OZw{  
{ B
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int n = -1; kTfE*We9  
try{ KX^!t3l6  
oSavedFile.write(b,nStart,nLen); t!&p5wJ*Q  
n = nLen; !CUy{
nV  
} "MPr'3  
catch(IOException e) f5`q9w_c  
{ q |Orv=v  
e.printStackTrace (); @#>YU
  
} tE$oV  
;[q>  
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return n; AT-  
} 89YG `  
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} ,ieew`  
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3>#io^35  
/* qir8RPW  
**SiteInfoBean.java VfT@;B6ALF  
*/ 1uJpn  
package NetFox; p_EWpSOt7  
8
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public class SiteInfoBean { P_F0lO  
}Ryrd!3bY  
[l*;+N+  
private String sSiteURL; //Site's URL APv& ^\oUH  
private String sFilePath; //Saved File's Path Rebo.6rG  
private String sFileName; //Saved File's Name G\B:i
yKl  
private int nSplitter; //Count of Splited Downloading File 1#lH5|XQ  
~93#L_V_O  
I~&*8)x
M  
public SiteInfoBean() n%d7`?tm4  
{//nSplitter的缺省值为5 +EvY-mwfQ  
//default value of nSplitter is 5 -1%AM40j  
this("","","",5); hr?0RPp}  
} Kwo0%2Onkd  
&9khIJIn  
D9r4oRkP*  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) >l=;6QL  
{ *lBX/O`=  
sSiteURL= sURL; l}XnCOIT,  
sFilePath = sPath; Z!z#+G  
sFileName = sName; V5!mV_EoR@  
this.nSplitter = nSpiltter; ;6q`c!p7  
v9GfudTZR  
{q/D,Rh8  
} 0[92&:c,  
'"9Wt@ .  
0O|l7mCr%I  
public String getSSiteURL() F @uOXNz)  
{ q\d/-K  
return sSiteURL; M!O &\2Q  
} }UWi[UgA  
'^`%  
| W<jN  
public void setSSiteURL(String value) roNs~]6  
{ 5iZ;7 ?(  
sSiteURL = value; ]DK.4\^  
} PX5U)  
|D~#9  
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public String getSFilePath() !U~S7h}  
{ ADT8A."R[  
return sFilePath; #RWmP$+#=  
} Jzj>=jWX@  
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;*>':-4  
public void setSFilePath(String value) $
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{ 2T-3rC)  
sFilePath = value; WjF#YW\  
} 8M6Qn7{L  
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,H5o/qNU`{  
public String getSFileName() 9@8)ZHf  
{ QV_Ep
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return sFileName; _MzdbUb5,  
} gjPbhY=C[  
gacE?bW'  
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public void setSFileName(String value) tybM3VA  
{ R
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sFileName = value; ;s w3MRJ  
} 7s2e>6Q[  
s AlOX`t  
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public int getNSplitter() zF_aJ+i:~  
{ 86m
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return nSplitter; )"&\S6*!  
} .!Q?TSQ+{!  
4/QQX;w  
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public void setNSplitter(int nCount) skBzwVW I  
{
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nSplitter = nCount; lKLb\F%  
} "xE;IpO[  
} xi!R[xr1  
{>zQW{!  
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/* Vf`9[*j  
**Utility.java cB2jf</  
*/ 

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package NetFox; ka[%p,H  
@^K_>s9B  
[p 8fg!|  
public class Utility { d>jRw  
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<UBB&}R0  
public Utility() AGgL`sP  
{ zK ir  
%( o[Hsl  
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} )jaNFJ 3  
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//线程睡眠 ARa9Ia{@  
public static void sleep(int nSecond) D(^ |'1  
{ ~
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try{
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Thread.sleep(nSecond); F(+dX4$  
} .="[In'  
catch(Exception e) w\Bx=a>vc  
{ 4P$#m<;t  
e.printStackTrace (); XjV,wsZ=  
} O-YB+~"3Z  
} ]5hGSl2  
X?Z#k~JR  
//日志 UY*[='l!)  
public static void log(String sMsg) gj<Y+Dv>  
{ p/%B>Y>  
System.err.println(sMsg); CsW*E,|xyP  
} H2D j`0  
7EukrE<b'  
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public static void log(int sMsg) mp+lN:  
{ 62z"cFN  
System.err.println(sMsg); 2=ZZR8v  
} T0Zv.  
} ]WP[hF  
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E/N*n!sV  
/* Tq=OYJq5U  
**TestMethod.java .~fAcc{Qj  
*/ VS_xC$X!S  
package NetFox; w`F4.e  
hu''"/raM  
lhLE)B2a2  
public class TestMethod { K/+w6d  
%b(non*  
\IG"Te  
public TestMethod() 4'ymPPY  
{ ///xx/weblogic60b2_win.exe Xv1mjHZCC  
try{ qOd*9AS'|M  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ,c_NXC^X?  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Uq}-<q  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ;~5w`F)  
fileFetch.start(); }^Kye23  
} STH?X] /  
catch(Exception e){e.printStackTrace ();} qX?k]m   
`VxfAV?}  
d)X6x-(  
} %knPeo&  
d)7V:  
"vnWq=E2  
public static void main(String[] args) }v?_.MtS  
{ G~;hD-D~.  
new TestMethod(); L?gak@E  
} *K1GX  
} h%T$m_  
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