http断点续传简单实现（java)

/* QWO]`q`|  
**SiteFileFetch.java grom\  
*/ :1wrVU-?h  
package NetFox; WNX5iwm  
import java.io.*; .qD@ Y3-  
import java.net.*; p3x?[Ww  
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public class SiteFileFetch extends Thread { U]6&b  
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SiteInfoBean siteInfoBean = null; //文件信息Bean (nSml,g
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long[] nStartPos; //开始位置 0JyVNuHn  
long[] nEndPos; //结束位置 HM[klH]s=  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 "E*e2W  
long nFileLength; //文件长度 "9y( }   
boolean bFirst = true; //是否第一次取文件 K7TzF&  
boolean bStop = false; //停止标志 j f~wBmd7  
File tmpFile; //文件下载的临时信息 lTRl"`@S  
DataOutputStream output; //输出到文件的输出流 ,I.WX,OR  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） e)^j+ l  
public SiteFileFetch(SiteInfoBean bean) throws IOException 6cS>bl  
{ X*eW#|$\  
siteInfoBean = bean; Vzlh+R>c  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); uBnoQ~Qd[z  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); K!z
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if(tmpFile.exists ()) p]G3)s@>  
{ w!^~<{Kz  
bFirst = false; G7LIdn=  
read_nPos(); Q\Kx"Y3i  
} \fWW'  
else 'cZN{ZMWG  
{ TYns~X_PR  
nStartPos = new long[bean.getNSplitter()]; "h"NW[R  
nEndPos = new long[bean.getNSplitter()]; T<b+s#n4  
} kyw/LE3$-  
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} -~f511<  
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public void run() G'z{b$?/[  
{ =<z.mzqu5  
//获得文件长度 1=}qBR#scY  
//分割文件 '\q f^?9  
//实例FileSplitterFetch ~g;   
//启动FileSplitterFetch线程 {MdLX.ycc)  
//等待子线程返回 k0z&v <  
try{ ,YYVj{~2  
if(bFirst) 2{,n_w?Wy  
{ 9SQ4cv*2  
nFileLength = getFileSize(); A=5epsB  
if(nFileLength == -1) q%YV$$c  
{ R,2P3lv1v@  
System.err.println("File Length is not known!"); 0ZpFE&  
} CO+/.^s7}S  
else if(nFileLength == -2) (7FW9X;  
{ LtgXShp_!  
System.err.println("File is not access!"); ,,L2(N  
} VR{+f7:}  
else tB7}|jC  
{ d(`AXyw  
for(int i=0;i<nStartPos.length;i++) vV?rpe|%  
{ c"tJld5F_  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); vdDludEv  
} XM1`x  
for(int i=0;i<nEndPos.length-1;i++) }R4c  
{ ;lX(}2tXW  
nEndPos = nStartPos[i+1]; E.bi05l  
} sW#JjtK  
nEndPos[nEndPos.length-1] = nFileLength; PCrU<J 7  
} }G<T:(a  
} `lDut1J5n  
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//启动子线程 `6Qdfmk=  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; |R/.r_x,V?  
for(int i=0;i<nStartPos.length;i++) d)o!
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{ Ck =;1sGh  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), B$Z3+$hfF  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), m#/_x  
nStartPos,nEndPos,i); Z;Rp+X  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); U5HKRO  
fileSplitterFetch.start(); HmmS(fU  
}
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// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), #EGA#SKo
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ,B}I?vN.  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", fU3`v\
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nEndPos = " + nFileLength); 7}O.wUKw%  
// fileSplitterFetch[nPos.length-1].start(); D#A~Nbc  
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//等待子线程结束 b^c9po  
//int count = 0; smY$-v)@  
//是否结束while循环 CWo1.pVw  
boolean breakWhile = false; '|>9C^E9X  
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while(!bStop) -D^A:}$  
{ )3<:tV8  
write_nPos(); o_M.EZO  
Utility.sleep(500); _Us*+ 2(4L  
breakWhile = true; A=zPLq{Sb  
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for(int i=0;i<nStartPos.length;i++) |%a4`
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{ %h"z0@+  
if(!fileSplitterFetch.bDownOver) d'6|:z9c  
{ w@\vHH.;V  
breakWhile = false; hG~reVNf  
break; @Y,7'0U  
} #3=P4FUz.  
} ?Ucu#UO
 
if(breakWhile) HBE.F&C88  
break; 3ss6_xd+  
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//count++; W,@ If}  
//if(count>4) &5{xXWJK  
// siteStop(); mV^Zy  
} dBV7Te4L  
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System.err.println("文件下载结束！"); i|)Su
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} 6&Juv  
catch(Exception e){e.printStackTrace ();} 5m:i6,4  
} RyB~Lm`ZK%  
hd V1nS$  
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//获得文件长度 ;< )~Y-  
public long getFileSize() oY~ Dg  
{ ~n')&u{  
int nFileLength = -1; Z4$cyL'
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try{ [ =x s4=  
URL url = new URL(siteInfoBean.getSSiteURL()); 4F>Urh+  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); t&Os;x?To?  
httpConnection.setRequestProperty("User-Agent","NetFox"); /y7M lU9  
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int responseCode=httpConnection.getResponseCode(); P #F=c34u  
if(responseCode>=400) vzel#  
{ Y!q!5Crfi  
processErrorCode(responseCode); r,goRK.  
return -2; //-2 represent access is error Hd7,ZHj3^  
} C9DJO:f.2y  
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String sHeader; I\?9+3 XnQ  
. #Z+Z  
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for(int i=1;;i++) :f5s4N  
{ UX<Qcjm$e  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); +bK.NcS  
//Utility.log(in.readLine()); ^ 5VK>  
sHeader=httpConnection.getHeaderFieldKey(i); GhY1k";  
if(sHeader!=null) 5m=I*.qE  
{ MC((M,3L  
if(sHeader.equals("Content-Length")) bb42
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{ b?4/#&z]  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); M}_i52  
break; Kz<@x`0   
} 8By,#T".  
} ]u-]'P  
else I]Tsz'T!9  
break; ``,k5!a66\  
} 3lLMu B+  
} E+"dq
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catch(IOException e){e.printStackTrace ();} ._wkj  
catch(Exception e){e.printStackTrace ();} Giq=*D+  
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Utility.log(nFileLength); 5G0
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return nFileLength; b5m=7;u*h  
} MC0TaP  
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//保存下载信息（文件指针位置） cw&Hgjj2  
private void write_nPos() @ DZD  
{ O9'x-A%  
try{ +5.t. d  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ri C[lB  
output.writeInt(nStartPos.length); N4;7gSc"  
for(int i=0;i<nStartPos.length;i++) ]Mj/&b>"e  
{ Sp}D;7  
// output.writeLong(nPos); vhvdKD  
output.writeLong(fileSplitterFetch.nStartPos); vQF vtwd  
output.writeLong(fileSplitterFetch.nEndPos); cH<q:OYi  
} gef6pfV  
output.close(); `G1&Z]z  
} 2eeQ@]Wj[Z  
catch(IOException e){e.printStackTrace ();} kVI#(uO  
catch(Exception e){e.printStackTrace ();} sC00un%  
} S~qZr  
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//读取保存的下载信息（文件指针位置） 9p 4"r^  
private void read_nPos() Obw?_@X  
{ '^%~JyU  
try{ )CI1;  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); w|mb4AyL{?  
int nCount = input.readInt(); 
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nStartPos = new long[nCount]; d|Gl`BG   
nEndPos = new long[nCount];
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for(int i=0;i<nStartPos.length;i++) M,j(=hRJ/E  
{ &)i|$J 2.  
nStartPos = input.readLong(); E6Rz@"^XV  
nEndPos = input.readLong(); sfr(/mp(  
} n/QF2&X7)  
input.close(); =O _z(  
} d1!i(MaV!  
catch(IOException e){e.printStackTrace ();} ~zm7?_"@]  
catch(Exception e){e.printStackTrace ();} jUj<~:Q}3o  
} #{r#;+  
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private void processErrorCode(int nErrorCode) nI*/Mhx  
{ FZd.L6q  
System.err.println("Error Code : " + nErrorCode); Mcw4!{l`  
} n[Zz]IO,g  
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//停止文件下载 $@\mpwANl  
public void siteStop() Z') pf  
{ rOW-0B+N  
bStop = true; n}A\2bO  
for(int i=0;i<nStartPos.length;i++) . .QB~  
fileSplitterFetch.splitterStop();
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} C\_zdADUb%  
} N_4eM,7t  
//负责部分文件的抓取 _a_xzv'  
**FileSplitterFetch.java *KK+X07  
*/ rI5Foh6  
package NetFox; vgn@d,v  
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import java.io.*; rdJm{<  
import java.net.*; -3Avs9`5  
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public class FileSplitterFetch extends Thread { 4vK8kkW1  
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String sURL; //File URL y`e4;*1  
long nStartPos; //File Snippet Start Position Xqp|VbDca  
long nEndPos; //File Snippet End Position JXiZB 8}  
int nThreadID; //Thread's ID 8T;IZ(s  
boolean bDownOver = false; //Downing is over n<Svwa}  
boolean bStop = false; //Stop identical wI
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FileAccessI fileAccessI = null; //File Access interface {vaaFs  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException DPe]daF  
{ +c:3o*  
this.sURL = sURL; 4A{|[}!  
this.nStartPos = nStart; nU+tM~C%a  
this.nEndPos = nEnd; ?:^mBb)T  
nThreadID = id; n?#!VN3  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Z>F^C}
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} Nd:R" p*8  
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public void run() +i `*lBup$  
{ (VvKGh  
while(nStartPos < nEndPos && !bStop) LiDvaF:@L!  
{ dGZntT2D  

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try{ J?)RfK|!  
URL url = new URL(sURL); LCXO>MXN  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ZZ/cq:3$P  
httpConnection.setRequestProperty("User-Agent","NetFox"); @e~]t}fH  
String sProperty = "bytes="+nStartPos+"-"; 
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httpConnection.setRequestProperty("RANGE",sProperty); di9!lS$  
Utility.log(sProperty); ,O=a*%0rt  
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InputStream input = httpConnection.getInputStream(); !=Y;h[J.p  
//logResponseHead(httpConnection); CR4rDh8za  
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byte[] b = new byte[1024]; ;y?);!g  
int nRead; _\5~>g_  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 71FeDpe  
{ 6XEZ4Q
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nStartPos += fileAccessI.write(b,0,nRead); `U!y
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//if(nThreadID == 1) GYRYbiwqdi  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); '/0#lF  
} W:&R~R  
k!jNOqbb  
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Utility.log("Thread " + nThreadID + " is over!"); K5 3MMH[q#  
bDownOver = true; VCNT4m  
//nPos = fileAccessI.write (b,0,nRead); Mro4`GL  
} gLD`wfZR  
catch(Exception e){e.printStackTrace ();} {!ZyCi19  
} ^jdL@#k00  
} |
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//打印回应的头信息 ,reJ(s  
public void logResponseHead(HttpURLConnection con) ~ <0Z>qr  
{ :L?_
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for(int i=1;;i++) FD7H@L5
 
{ hVoNw6fE  
String header=con.getHeaderFieldKey(i);
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if(header!=null) 9V1cdb~?"T  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); P=AS>N^yaL  
Utility.log(header+" : "+con.getHeaderField(header)); O[~x_xeW  
else S{F-ttS"  
break; 4Tzd; P6_  
} 3{raKM6F  
} !&kL9A).  
+,'T=Ic{  
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public void splitterStop() ! U0z"  
{ \L!uHAE2a  
bStop = true; `&7RMa4=  
} A Ayv  
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} :bM+&EP  
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/* C.a5RF0  
**FileAccess.java TT!ET<ciN  
*//文件访问(定位，写) Hy
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package NetFox; 7l8[xV  
import java.io.*; j28_HhT  
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public class FileAccessI implements Serializable{ Id8wS!W`7  
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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 V*n==Nb5L  
RandomAccessFile oSavedFile; 5vp|?-\h>  
long nPos; A;K(J4y*  
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public FileAccessI() throws IOException -<f/\U  
{ 0Vv9BL{  
this("",0); *DeTqO65  
} HB& &  
<)m%*9{  
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public FileAccessI(String sName,long nPos) throws IOException ,4F,:w  
{ 9
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oSavedFile = new RandomAccessFile(sName,"rw"); `_AM` >_  
this.nPos = nPos; 0LVE@qEL  
oSavedFile.seek(nPos); #Fd W/y5  
} DQ!J!ltQ  
3><u*0qe%I  
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public synchronized int write(byte[] b,int nStart,int nLen) 8:;#,Urr  
{ D!> d0k,Y  
int n = -1; e$l6gY  
try{ LVtu*k   
oSavedFile.write(b,nStart,nLen); 9Ld9N;rWm#  
n = nLen; <bmLy_":  
} hq_~^/
v\  
catch(IOException e) )@7DsV/M  
{ ija:H'j  
e.printStackTrace (); s${_K*g6  
} =G>(~+EA  
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return n; ] pPz@@xx  
} /)#8)"`nT  
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} ?X_V#8JK  
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/* O]=C#E{  
**SiteInfoBean.java ?C;JJ#Ho  
*/ D[Iqn  
package NetFox; w+UV"\!G)Q  
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public class SiteInfoBean { 8OAg~mQ15(  
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private String sSiteURL; //Site's URL xfHyC'?  
private String sFilePath; //Saved File's Path !Tfij(91  
private String sFileName; //Saved File's Name F>Jg~ FD*  
private int nSplitter; //Count of Splited Downloading File iBb
br,  
i^|@"+  
4,}GyVJFb`  
public SiteInfoBean() MV936  
{//nSplitter的缺省值为5 I-:`cON=G  
//default value of nSplitter is 5 Vewzo1G2  
this("","","",5); d'zT:g  
} H?:Jq\Ba0  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) kL7^$  
{ ?SX_gYe9  
sSiteURL= sURL; 1r4,XSk  
sFilePath = sPath; 981!2*  
sFileName = sName; ~mH+DV3  
this.nSplitter = nSpiltter; Jp]T9W\  
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} ^ }#f()  
j[DIz@^  
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public String getSSiteURL() h([0,
:\  
{ 6E+=Xi  
return sSiteURL; &BgU:R,  
} ,P@QxnQ   
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JSjYC0e  
public void setSSiteURL(String value) q|{tQJfYg  
{ k>{-[X,/OV  
sSiteURL = value; Z=9dMND  
} G[6=u|(M  
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< l[
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public String getSFilePath() M {xie  
{ .BL:h&h|y  
return sFilePath; Nmf#`+7gCI  
} <nA3Sd"QfV  
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T46{*(  
public void setSFilePath(String value) V_]-`?S  
{ :&$Xe1)i]  
sFilePath = value; "jGe^+9uT  
} tc/jY]'32  
dofR)"<p,^  
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public String getSFileName() ^ wQcB  
{ Q-Y@)Mf~?0  
return sFileName; \UQ],+H  
} @Z2/9K%1'  
/nM*ljfB\  
4~WlP,,M  
public void setSFileName(String value) Kq6qXc\x  
{ WguV{#=H  
sFileName = value; 6DZ2pT:  
} a}D&$yz2  
X,53c$  
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public int getNSplitter() g.&\6^)8p  
{ SA3Y:(  
return nSplitter; j&}B<f _6J  
} ^V,@=QL3U  
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public void setNSplitter(int nCount) MZ
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{ b
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nSplitter = nCount; *<3iEeO/R  
} EEg O  
} -AeHY'T  
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/* ke</x+\F  
**Utility.java |vN$"mp^a  
*/ "j;!_v>=f`  
package NetFox; 73#9NZR  
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public class Utility { sp,(&Y]US  
| &\^n2`>  
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public Utility() ~pwY6Q  
{ pb=HVjW<  
6KBHRt  
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} @%7
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X)FQ%(H<  
//线程睡眠 g&8.A(  
public static void sleep(int nSecond) W.sD2f  
{ ,|>nF;.Y  
try{ otZ JY)  
Thread.sleep(nSecond); m&{rBz0  
} $q=
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catch(Exception e) ^:$j:w?j  
{ PE +qYCpP9  
e.printStackTrace (); )%1&/uN)  
} M{y|7e%K  
} c'[( d5^|  
CTh1;U20  
//日志 fY2l.H\f  
public static void log(String sMsg) ;W =by2x*  
{ wf^cyCR0  
System.err.println(sMsg); _4De!q0(  
} lHRK'?Q  
0$(jBnE  
4>d[qr*<  
public static void log(int sMsg) A'w2GC{.  
{ 4O9tx_<JG  
System.err.println(sMsg); *,_2hvlz  
} y& Gw.N}<r  
} A` oa|k!U  
sV;qpDXX  
7YSuB9{M  
/* ]lC4+{V  
**TestMethod.java <4SF~i  
*/ ~n)]dFy  
package NetFox; gS0,')w  
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public class TestMethod { jR}*bIzv  
_qdWQFuM  
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public TestMethod() -1dIZy  
{ ///xx/weblogic60b2_win.exe UeC 81*XZ  
try{ 3<yCe%I:  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); J#_\+G i  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); &7JEb]1C  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ~p0e=u  
fileFetch.start(); E%KC'TN^D  
} 1"N/ZKF-x  
catch(Exception e){e.printStackTrace ();} 30:HRF(:  
6!i( \Q*  

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} 4ZSfz#<[z  
K4BTk!  
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public static void main(String[] args) 4d,qXSKty  
{ HE4`9$kVLr  
new TestMethod(); qLU15cOM  
} Ul7,k\q@  
}  ||bA  
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