http断点续传简单实现（java)

/* &ub0t9R  
**SiteFileFetch.java 8AuOe7D9A  
*/ Q,<V)  
package NetFox; VVDd39q  
import java.io.*; oeIza<:=R  
import java.net.*; xty)*$C>  
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public class SiteFileFetch extends Thread { N Obw/9JO  
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SiteInfoBean siteInfoBean = null; //文件信息Bean n(?BZ'&!O  
long[] nStartPos; //开始位置 Gsa~zGN  
long[] nEndPos; //结束位置 ?5jq)xd2  
FileSplitterFetch[] fileSplitterFetch; //子线程对象  Va3/#is'  
long nFileLength; //文件长度 8a,pDE  
boolean bFirst = true; //是否第一次取文件 L@>$ Aw  
boolean bStop = false; //停止标志 JJVdq-k+`  
File tmpFile; //文件下载的临时信息 PiZU_~A  
DataOutputStream output; //输出到文件的输出流 +jN%w{^=  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） r%UsUj  
public SiteFileFetch(SiteInfoBean bean) throws IOException IT=<p60"  
{ mVNHH!  
siteInfoBean = bean; ~"}o^#@DwJ  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Gx/kel[Y}  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); @z1pE@7jK  
if(tmpFile.exists ()) kYnp$8  
{ y,cz;2  
bFirst = false; s?~lM
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read_nPos(); )0N^rw kW  
} A#KfG1K>  
else %8$ldNhV  
{ \zM3{{mV/  
nStartPos = new long[bean.getNSplitter()]; ds;c\x  
nEndPos = new long[bean.getNSplitter()]; /YHAU5N/}  
} =--oH'P=M  
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} nC(<eL  
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public void run() R8C#DB  
{ ()o[(Hx+ph  
//获得文件长度 z6x`O-\  
//分割文件 M~,N~ N1  
//实例FileSplitterFetch &"'Z)iWm  
//启动FileSplitterFetch线程 uN+]q qCf  
//等待子线程返回 Z+g9!
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try{ Q]hl+C$d"/  
if(bFirst) 
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{ ~Y3X*  
nFileLength = getFileSize(); i.Z iLDs\7  
if(nFileLength == -1) 20?@t.aMp  
{ Qs\*r@6?  
System.err.println("File Length is not known!"); 8"yZS)09  
} Wf:LYL  
else if(nFileLength == -2) ,jq:%Y[KZ  
{ SI, t:=D  
System.err.println("File is not access!"); vtF|:
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} EaKbG>  
else ><i: P*ht  
{ E_-QGE/1  
for(int i=0;i<nStartPos.length;i++) P^[y~I#{  
{ _bn "c@s  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 9
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} 0S2/,[-u+  
for(int i=0;i<nEndPos.length-1;i++) K7c[bhi_w  
{ j06qr\Es  
nEndPos = nStartPos[i+1]; vo>i36  
} XJe}^k  
nEndPos[nEndPos.length-1] = nFileLength; 2KtK.2;7  
} a4\j.(w)$D  
} E{BX $R_8  
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//启动子线程 W^YaC (I  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 8F9x2CM-[C  
for(int i=0;i<nStartPos.length;i++) $0XR<D  
{ wDDNB1_E  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), NOFuX9/'w  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), apZPHau6h  
nStartPos,nEndPos,i); `!Yd$=*c_&  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); =z[$o9  
fileSplitterFetch.start(); %U6A"?To  
} DIw9ov>k  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), y}1Pc
*  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Q?>DbT6  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 7#(0GZN9h%  
nEndPos = " + nFileLength); se=;vp]3a  
// fileSplitterFetch[nPos.length-1].start(); Xm3r)Bm'3  
4 (XV)QR  
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//等待子线程结束 ]-;M
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//int count = 0; spT$}F2n  
//是否结束while循环 
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boolean breakWhile = false; U^8S@#1Q  
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while(!bStop) !<>*|a  
{ eZBC@y  
write_nPos(); \,ne7G21j  
Utility.sleep(500); Ot`znJU@  
breakWhile = true; jN-!1O._G  
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for(int i=0;i<nStartPos.length;i++) 055C1RV%  
{
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if(!fileSplitterFetch.bDownOver) >t{-_4Yv?  
{ JOH\K0=e  
breakWhile = false; X0Wx\xDg[  
break; +ZOK
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} =Cd{bj.8  
} SY.ZEJcv  
if(breakWhile) <nTZs`$LwL  
break; zx5#eMD  
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//count++; td7Of(k'  
//if(count>4) +)LCYDRV7  
// siteStop(); }U'  
} mLx=Zes:.  
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System.err.println("文件下载结束！"); n?U^vK_  
} U(Tl$#Bt  
catch(Exception e){e.printStackTrace ();} O?ODfO+>  
} g(9kc<`3'D  
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#Vu;R5GZ}  
//获得文件长度 1'N<ITb  
public long getFileSize() v*OV\h.  
{ !_FTy^@c2  
int nFileLength = -1; nxB[To*P  
try{ zz!jt A  
URL url = new URL(siteInfoBean.getSSiteURL()); *d`KD64  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); `~z[Hj=2  
httpConnection.setRequestProperty("User-Agent","NetFox"); 3"juj'  
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int responseCode=httpConnection.getResponseCode(); 2Z5_@Y  
if(responseCode>=400) w{t]^w:  
{ r.lHlHl  
processErrorCode(responseCode); wX$|(Y}  
return -2; //-2 represent access is error
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} ,"
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String sHeader; y+Hz(}4  
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for(int i=1;;i++) 684d&\(s  
{ >JAWcT)d  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); T@*'}*  
//Utility.log(in.readLine()); y$9! rbL  
sHeader=httpConnection.getHeaderFieldKey(i); 3H0B+F2XQ  
if(sHeader!=null) PfyJJAQ[  
{ `lQ;M?D  
if(sHeader.equals("Content-Length")) YWs?2I  
{ :Nv7Wt!  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); `a!9_%|8  
break; |j81?4<)v  
} M
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} -Lu&bVt<>  
else R}cNhZC  
break; .xuzu#-  
} jRd$Vt  
} #lg R"%  
catch(IOException e){e.printStackTrace ();} $wi4cHh  
catch(Exception e){e.printStackTrace ();} _6V1oe2  
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Utility.log(nFileLength); c#>(8#'.U  
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return nFileLength; -jy0Kl/p  
} T=)qD2?  
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//保存下载信息（文件指针位置） =JW-EQ6[T  
private void write_nPos() co3\1[q"b  
{ ;-XfbqZ\  
try{ vzFpXdt  
output = new DataOutputStream(new FileOutputStream(tmpFile)); \1LfDlQk)  
output.writeInt(nStartPos.length); o<%0|n_O&  
for(int i=0;i<nStartPos.length;i++) ^!d0abA  
{ NPS*
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// output.writeLong(nPos); #4b]j".P!n  
output.writeLong(fileSplitterFetch.nStartPos); TYb$+uY  
output.writeLong(fileSplitterFetch.nEndPos); `CH,QT7e  
} bc4V&  
output.close(); ]d-.Mw,'  
} o{! :N>(  
catch(IOException e){e.printStackTrace ();} ! xG*
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catch(Exception e){e.printStackTrace ();} \Dy|}LE  
} A+gS'DZ9C  
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//读取保存的下载信息（文件指针位置） E_aBDiyDf  
private void read_nPos() Y*PfU+y~  
{ g_`a_0v  
try{ 9$Z0mzk  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ~r!(V;k{  
int nCount = input.readInt();
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nStartPos = new long[nCount]; &H]/'i-  
nEndPos = new long[nCount]; RG""/x;  
for(int i=0;i<nStartPos.length;i++) [5& nH@og  
{ #MlpOk*G  
nStartPos = input.readLong(); Y}v3
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nEndPos = input.readLong(); U31@++C[  
} DrkTM<  
input.close();  L"%SU  
} eu9*3'@A  
catch(IOException e){e.printStackTrace ();} [)1vKaC  
catch(Exception e){e.printStackTrace ();} kI)}7e  
} vM6W64S  
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private void processErrorCode(int nErrorCode) } P ,"  
{ z&t
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System.err.println("Error Code : " + nErrorCode); @
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} sHc-xnd  
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//停止文件下载 )\=
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public void siteStop() w+R7NFq  
{ >e>3:~&2  
bStop = true; NeG`D'  
for(int i=0;i<nStartPos.length;i++) Q`<{cFsU  
fileSplitterFetch.splitterStop(); xlS*9>Ij  
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} .Mb[j1L^  
} ur\6~'l4  
//负责部分文件的抓取 L|T?,^  
**FileSplitterFetch.java Rbf6/C  
*/ , :#bo]3  
package NetFox; 32<D9_  
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import java.io.*; #~|k EGt  
import java.net.*; P,{Q k~iu  
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public class FileSplitterFetch extends Thread { KU/r"lMNlU  
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String sURL; //File URL "mW'tm1+  
long nStartPos; //File Snippet Start Position oNAnJ+_  
long nEndPos; //File Snippet End Position igfQ,LWe!  
int nThreadID; //Thread's ID &Mk!qE<:N  
boolean bDownOver = false; //Downing is over ]=qauf>3  
boolean bStop = false; //Stop identical oCaYmi=:  
FileAccessI fileAccessI = null; //File Access interface J8alqs7  
+ U5Q/g  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 3!{imQT  
{ oQ<[`.s  
this.sURL = sURL; FN-/~Su~J  
this.nStartPos = nStart; $u!(F]^  
this.nEndPos = nEnd; FOsd{Fw  
nThreadID = id; U`ttT5;  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 !H\oQv-I  
} sv%X8  
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public void run() Qh1pX}X  
{ "/aZ*mkjfJ  
while(nStartPos < nEndPos && !bStop) PN l/}'  
{ 0\tac/  
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try{ K {' atc  
URL url = new URL(sURL); p|-MwCeH  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); SN}K=)KF#  
httpConnection.setRequestProperty("User-Agent","NetFox"); DWt|lO  
String sProperty = "bytes="+nStartPos+"-"; K6IT$
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httpConnection.setRequestProperty("RANGE",sProperty); x|0C0a\"A  
Utility.log(sProperty); 2`$*HPj+G  
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InputStream input = httpConnection.getInputStream(); 2d[q5p  
//logResponseHead(httpConnection); L/tpT?$fi  
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byte[] b = new byte[1024]; Trv}YT.  
int nRead; :W*yfhLt  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) <T}U 3lL^  
{ L7
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nStartPos += fileAccessI.write(b,0,nRead); )}@D\(/@  
//if(nThreadID == 1) ~v;I>ij  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); nHdQe  
} X
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Utility.log("Thread " + nThreadID + " is over!"); @Z~YFnEJi  
bDownOver = true; \Ggh 95y  
//nPos = fileAccessI.write (b,0,nRead);
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} Ib#-M;{  
catch(Exception e){e.printStackTrace ();} bej(Ds0  
} I@cw=_EQL  
} .uJ J<  
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//打印回应的头信息 6nW)2
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public void logResponseHead(HttpURLConnection con) PlkZ)S7C  
{ loVg{N:  
for(int i=1;;i++) Fc5.?X-  
{ PAYw:/(P  
String header=con.getHeaderFieldKey(i); O+}py{ st  
if(header!=null) N#T'}>ty  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ^jMrM.GY  
Utility.log(header+" : "+con.getHeaderField(header)); + `|A/w  
else s:3[#&PQpN  
break; .Fo#Dmq3  
} "JB4Uaa  
} TJ"-cWpO1  
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public void splitterStop() BiYxI{VFD  
{ b)d;eS  
bStop = true; BDI|z/~&  
} [H}> 2Q  
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} ^9
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/* 5kiW@{m  
**FileAccess.java <w2h@ea  
*//文件访问(定位，写) 1rm\u%  
package NetFox; =tOB fRM  
import java.io.*; FiUQ2w4  
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public class FileAccessI implements Serializable{ 3`^@
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 k*$WAOJEW  
RandomAccessFile oSavedFile; iOk;o=  
long nPos; 8o~ NJ 6  
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public FileAccessI() throws IOException xb;{<~`71  
{ l0Q5q)U1A  
this("",0); E-z5mX.2  
} Vu$m1,/  
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public FileAccessI(String sName,long nPos) throws IOException ZNQx;51  
{ 5CY%h  
oSavedFile = new RandomAccessFile(sName,"rw"); [neuwdN  
this.nPos = nPos; E5ce=$o  
oSavedFile.seek(nPos); "-Q+!byh  
}
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b84
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public synchronized int write(byte[] b,int nStart,int nLen) up5f]:!  
{ cC/h7odY  
int n = -1; >d +
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try{ b$_81i  
oSavedFile.write(b,nStart,nLen); 7gC?<;\0  
n = nLen; M"
3"6U/e  
} =[(34#  
catch(IOException e) ,H]%4@]|o  
{ S/]\GG{  
e.printStackTrace (); gb_Y]U  
} ,X@o@W+L  
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return n; yK*vn]}  
} _Sr}3  
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} `2.c=,S{  
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/* $.`o  
**SiteInfoBean.java ER"69zQg|2  
*/ ofy"SM  
package NetFox; CWdsOS=  
T fLqxioqZ  
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public class SiteInfoBean {
~
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private String sSiteURL; //Site's URL f[o~d`
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private String sFilePath; //Saved File's Path ',EI[ ]+  
private String sFileName; //Saved File's Name %Ig$:I(o  
private int nSplitter; //Count of Splited Downloading File ]oGd,v X  
$TIeeTB  
v=llg ^  
public SiteInfoBean() @v)Z>xv  
{//nSplitter的缺省值为5 Gx C+lqH#  
//default value of nSplitter is 5 }5 rR^ryA  
this("","","",5); i'ap8Dr  
} !ho^:}m  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) <h#*wy:o2  
{ 5u$.!l8Nl  
sSiteURL= sURL; g>/Y}{sL-  
sFilePath = sPath; eRMN=qP.q  
sFileName = sName; ^j}C]cq{Xg  
this.nSplitter = nSpiltter; F-m%d@P&X  
d/d)MoaJ*t  
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} >=@-]X2%j  
2`=jKt  
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public String getSSiteURL() MPB[~#:  
{ 7b"fpB  
return sSiteURL; | eBwcC#^  
} }_+XN"}C  
!*#9b  
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public void setSSiteURL(String value) Tz,-~mc  
{ 63fYX"  
sSiteURL = value; )@wC6Ij  
} e;.,x
5+  
X$kLBG_  
'cO8& |  
public String getSFilePath() p(F@lL-  
{ b<W\#3~G  
return sFilePath; JQQyl:=  
} F.vRs|fk  
0%f}Q7*R  
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public void setSFilePath(String value) .<m]j;|6  
{ Zl>SeTjB-  
sFilePath = value; Z '5itN^  
} YSnh2 Bq  
J9T2 p\5  
7@c!4hmr
U  
public String getSFileName()
A?YYR%o%'  
{ 3BMz{ny=  
return sFileName; p$Tk;;wm  
} j9
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^|/mn!7wD  
c9/w{
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public void setSFileName(String value) JH?ohA  
{ Cv#aBH'N  
sFileName = value; T~UDD3  
} +5y^c|L0  
";/]rwHa)  
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public int getNSplitter() lelmX  
{ T}Tv}~!f  
return nSplitter; ucl001EK  
} x;vfmgty  
$0Y`>3  
Z %pc"  
public void setNSplitter(int nCount) vobC/m  
{ %FjUtB  
nSplitter = nCount; W2{w<<\$3}  
} {K|?i9K  
}
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/* 2s}S9  
**Utility.java bm#5bhX\|  
*/ R}oN8
 
package NetFox; ILuQ.VhBVN  
(;fJXgj.  
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public class Utility { !8@yi"n  
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2Bt/co-~4  
public Utility() yi8vD~aA[  
{ i#:To |\u  
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}  +P(*S  
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//线程睡眠 <EC"E #p  
public static void sleep(int nSecond) aImzK/  
{ )
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try{ k8 #8)d  
Thread.sleep(nSecond); H&s`Xr  
} 9~V'Wev  
catch(Exception e) !*l/Pr^8  
{ }Y-V!z5z!  
e.printStackTrace (); hWly8B[I  
} Ti2cD  
} ~W@dF~r  
OP!R
>|  
//日志
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public static void log(String sMsg) *<\`"C;  
{ 89d%P J0  
System.err.println(sMsg); xh;gAh5n  
} W'6DwV|  
!oyo_h  
0YoKSo  
public static void log(int sMsg) v7(7WfqP  
{ ;Tbo \Wp9  
System.err.println(sMsg);  ]]p\1G  
} *k(FbZ  
} S$b)X"h  
8*-)[+s9il  
jwwRejNV  
/* u-~ec{oBu  
**TestMethod.java DVd8Ix<  
*/ 6vNW)1{nn  
package NetFox; (H:c80/V  
}hy4EJ  
AYf}=t|  
public class TestMethod { |6So$;`  
|>}CoR7  
ztU"CRa8  
public TestMethod() qX}3}TL  
{ ///xx/weblogic60b2_win.exe bB4FjC':  
try{ 2>jk@~Z1:u  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); jNxTy UU  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); =*fq5v  
SiteFileFetch fileFetch = new SiteFileFetch(bean); #GGa,@O  
fileFetch.start(); xn, u$@F  
} <?A4/18K  
catch(Exception e){e.printStackTrace ();} 7fqQ  
<^nS%hXEr  

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} '$,yV f  
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h`U-{VIrqi  
public static void main(String[] args) 7bYwh8  
{ R\cx-h*  
new TestMethod(); R.i]6H!  
} w*{{bISw|  
} W$]qo|2P  
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