http断点续传简单实现（java)

/* Ey_" ~OB  
**SiteFileFetch.java .Si,dc\  
*/ E5)
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package NetFox; [pl'|B  
import java.io.*; eCN })An  
import java.net.*; =+ytTQc*ot  
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public class SiteFileFetch extends Thread { #.it]Nv{  
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SiteInfoBean siteInfoBean = null; //文件信息Bean bu |a0h7e  
long[] nStartPos; //开始位置 ERpnuMb  
long[] nEndPos; //结束位置 l;JA8o\x  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 crqpV F]1]  
long nFileLength; //文件长度 V=zi >o`   
boolean bFirst = true; //是否第一次取文件 Y,WuBH  
boolean bStop = false; //停止标志 cV 5CaaL  
File tmpFile; //文件下载的临时信息  /<HRwG\w  
DataOutputStream output; //输出到文件的输出流 P/c&@_b  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 7N-
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public SiteFileFetch(SiteInfoBean bean) throws IOException :,Pn3xl
 
{ y=`2\L" O  
siteInfoBean = bean; h!&prY
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//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); {U!8|(  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 
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if(tmpFile.exists ()) Q7R~{5r>W  
{ ZT,B(#m  
bFirst = false; vg D77  
read_nPos(); j:k[90  
} Q?3Gk%T0[  
else Qk\A c  
{ \=uKHNP?#  
nStartPos = new long[bean.getNSplitter()]; ?*E'^~,H)  
nEndPos = new long[bean.getNSplitter()]; t"k*PA  
} -M[$Zy^  
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} G>wqt@%r9  
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public void run() BlXB7q,  
{ }RmU%IYc  
//获得文件长度 pcYG~pZ9  
//分割文件 IkBei&4F`  
//实例FileSplitterFetch Pm lx8@D  
//启动FileSplitterFetch线程 _acE:H  
//等待子线程返回 _C(m<n  
try{ XLAN Np%E  
if(bFirst) FP;Ccl"s  
{ @r#v[I  
nFileLength = getFileSize(); .Jt[(;  
if(nFileLength == -1) ;\lW5ZX  
{ et,f_fd7v  
System.err.println("File Length is not known!"); x
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} ]T;EdK-  
else if(nFileLength == -2) {) Q@c)'  
{ JS*m65e  
System.err.println("File is not access!"); um4yF*3b9  
} 4d8B`Fa9  
else &K/ya7  
{ qjf[zF  
for(int i=0;i<nStartPos.length;i++) } w 5l  
{ dZi(&s  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); '[C.|)"  
} H2um|6>  
for(int i=0;i<nEndPos.length-1;i++) F{eU";D  
{ G`\f  
nEndPos = nStartPos[i+1]; LUC4=kk4  
} ^j"
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nEndPos[nEndPos.length-1] = nFileLength; L5#P[cHzz  
} QAvir%Y9Q  
} ]@uE#a:[  
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//启动子线程 4g :>[q  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; GlbySD@
 
for(int i=0;i<nStartPos.length;i++) dHK`eS$sb  
{ wvbPnf^y  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), FI3)i>CnW  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 4$*%gL;f^  
nStartPos,nEndPos,i); zgs(Dt;  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); /%&2HDA)  
fileSplitterFetch.start(); %n h
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} c0hwc1kv-  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), n@U n  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); -C<zF`jO  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", (*oL+ef-C  
nEndPos = " + nFileLength); l-ct?T_@  
// fileSplitterFetch[nPos.length-1].start(); _~*,m#uxJ  
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h"_~7jq"  
//等待子线程结束 AwslWkd=  
//int count = 0; \/1<E?Q f  
//是否结束while循环 NGOqy+Ty{f  
boolean breakWhile = false; \hhmVt@@  
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while(!bStop)
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{ mml<
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write_nPos(); UN zlN  
Utility.sleep(500); -5T=:2M  
breakWhile = true; iVd.f A  
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for(int i=0;i<nStartPos.length;i++) TZ2=O<Kj  
{ !"<MsoY@  
if(!fileSplitterFetch.bDownOver) 9nH?l{As  
{ < V\I~;  
breakWhile = false; (rkU)Q  
break; wc!onZX5  
} 'JNElXqrv  
} {W]=~*w  
if(breakWhile) =k/IaFg 6w  
break;  b^p"|L  
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//count++;
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//if(count>4) CMn{LQcC  
// siteStop(); RB+N IoQQ|  
} hWKJ,r%9;  
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System.err.println("文件下载结束！"); vP!{",>  
} K^B%/T]d  
catch(Exception e){e.printStackTrace ();} $d
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} Q",0F{'  
 8HRmQ  
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//获得文件长度 z,VD=Hnz  
public long getFileSize() LrATSq@  
{ Ma+$g1
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int nFileLength = -1; QK+(g,)_86  
try{
ed:@C?  
URL url = new URL(siteInfoBean.getSSiteURL()); HO[wTB|D]  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ' 4ER00  
httpConnection.setRequestProperty("User-Agent","NetFox"); om]4
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int responseCode=httpConnection.getResponseCode(); (sQr X{~  
if(responseCode>=400) Vo7dAHHL  
{ :_@JA0n  
processErrorCode(responseCode); UQ[B?jc  
return -2; //-2 represent access is error .58qL-iC  
} I8QjKI (  
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String sHeader; Rcawc Y  
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for(int i=1;;i++) #Jna6  
{ HmZ{L +"  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); yB3;  
//Utility.log(in.readLine()); l/Vo-#  
sHeader=httpConnection.getHeaderFieldKey(i); =i(?deR  
if(sHeader!=null) hRq3C1mR  
{ 2CzaL,je[  
if(sHeader.equals("Content-Length")) AQc,>{Lm  
{ 5bA)j!#)|X  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ki{3IEOr}  
break; ,:%"-`a%  
} ) /v6l  
} >y}M.Mm  
else M{$j  
break; )LdyC`S\c  
} .-JCwnP  
} Q//,4>JKf  
catch(IOException e){e.printStackTrace ();} ?]rPRV
  
catch(Exception e){e.printStackTrace ();} VOr1  
/RyR>G!  
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Utility.log(nFileLength); !=y]Sv~h  
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return nFileLength; W;1|+6x  
} Q0\0f
 
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//保存下载信息（文件指针位置） Hk7q{`:N  
private void write_nPos() {VP$J"\e  
{ LPwT^zV&N  
try{ 4:7V./" 9  
output = new DataOutputStream(new FileOutputStream(tmpFile)); iL= m{  
output.writeInt(nStartPos.length); [lk'xzE  
for(int i=0;i<nStartPos.length;i++)
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{ ZbT/$\0(6  
// output.writeLong(nPos); 1RKW2RCaW_  
output.writeLong(fileSplitterFetch.nStartPos); :0/q5_t  
output.writeLong(fileSplitterFetch.nEndPos); siTX_`0  
} c,Euv>*`  
output.close(); .@"q$\  
} g!i45-n3gt  
catch(IOException e){e.printStackTrace ();} <jS~ WI@  
catch(Exception e){e.printStackTrace ();} 5~
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} unJ R=~E  
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//读取保存的下载信息（文件指针位置） .0G6flD   
private void read_nPos() fgj^bcp-  
{ '<R>E:5  
try{ !6G?zipB  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); j&UMjI9[  
int nCount = input.readInt(); NjE</Empb%  
nStartPos = new long[nCount]; v?c 0[+?  
nEndPos = new long[nCount]; }dxDtqb  
for(int i=0;i<nStartPos.length;i++) Bk}><H  
{ /cK%n4l.y  
nStartPos = input.readLong(); IG?'zppjd6  
nEndPos = input.readLong(); JxjI]SF02  
} "v}pdUW  
input.close(); xvNo(>  
} f/kI|Z  
catch(IOException e){e.printStackTrace ();} W- $a Y2  
catch(Exception e){e.printStackTrace ();} 5/QRL\  
} NWfAxkz{/  
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private void processErrorCode(int nErrorCode) \7z^!m  
{ <}jPXEB"  
System.err.println("Error Code : " + nErrorCode); =H8 xSJLh  
} 4gSH(*}  
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jEz+1Nl)  
//停止文件下载 @=5qT]%U3J  
public void siteStop() nJ?^?M'F%  
{ L&-hXGx=7  
bStop = true; 0e[d=)XG  
for(int i=0;i<nStartPos.length;i++) \#'TNmS  
fileSplitterFetch.splitterStop(); qi^!GA'5j  
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} Sb".]>^  
} !TAp+b  
//负责部分文件的抓取 B$?qQ|0:=  
**FileSplitterFetch.java XI Jlc~2  
*/ Zs2-u^3&  
package NetFox; I =Wc&1g  
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import java.io.*; uE=$p)  
import java.net.*; ( #Z`  
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public class FileSplitterFetch extends Thread { +KEkmXZ  
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String sURL; //File URL HftxS  
long nStartPos; //File Snippet Start Position fU2qrcVu  
long nEndPos; //File Snippet End Position ?@6/Alk  
int nThreadID; //Thread's ID *FR$vL
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boolean bDownOver = false; //Downing is over qP*}.Sqk7  
boolean bStop = false; //Stop identical zHfP+(ah  
FileAccessI fileAccessI = null; //File Access interface v=I|O%  
":Edu,6O  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException  \4ghYQ:  
{ *pzq.#  
this.sURL = sURL; wyxGe<1  
this.nStartPos = nStart; :`vP}I ^  
this.nEndPos = nEnd;  6qo^2  
nThreadID = id; ~9Cz6yF  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 i;PL\Er:tX  
} I/x iT  
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public void run() $mA5@O~C5\  
{ IB9%QW"0  
while(nStartPos < nEndPos && !bStop) T:asm1BC[  
{ 17g^ALs  
{}>n{_  
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try{ 9=dkx^q  
URL url = new URL(sURL); FZpKFsPx  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); pL1
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httpConnection.setRequestProperty("User-Agent","NetFox"); Lp:6 ;  
String sProperty = "bytes="+nStartPos+"-"; >n.z)ZJ  
httpConnection.setRequestProperty("RANGE",sProperty); m:Go-tk  
Utility.log(sProperty); >x:EJV   
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InputStream input = httpConnection.getInputStream(); |`yZIY_  
//logResponseHead(httpConnection); +$z]w(lbT  
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!$XHQLqF2  
byte[] b = new byte[1024]; ZC^C  
int nRead; }UyQ#U  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 3mt%!}S  
{ 6\dX
 
nStartPos += fileAccessI.write(b,0,nRead); Md;/nJO~{  
//if(nThreadID == 1) T9y;OG  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ZX`J8lZP  
} M"^K0 .  
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iy
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Utility.log("Thread " + nThreadID + " is over!"); w5~i^x  
bDownOver = true; r;cV&T/?  
//nPos = fileAccessI.write (b,0,nRead); R -e
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} :_dICxaLZT  
catch(Exception e){e.printStackTrace ();} K3$` Kv>I  
} _EYB 8e  
} FJM;X-UOY  
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//打印回应的头信息 ('o&Q_  
public void logResponseHead(HttpURLConnection con) @O3/3vi1  
{ (hZ:X)E>  
for(int i=1;;i++) <ZPZk'53<f  
{ +S{  
String header=con.getHeaderFieldKey(i); "4}wnu6/  
if(header!=null) zDBD.5R;  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ( 76{2  
Utility.log(header+" : "+con.getHeaderField(header)); - HOnB=  
else j^u[F"  
break; +QqH}= M  
} Zy]s`aa  
} ML!
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{/M\Q@j  
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public void splitterStop() \gKdDS  
{ sB*o)8  
bStop = true; MR9/Y:Nm  
} x6yW:tUG5  
,r+"7$  
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} ;( KMGir
 
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/* hH4o;0rqJ  
**FileAccess.java Sni=gZK  
*//文件访问(定位，写) #3.)H9  
package NetFox; *%- ?54B  
import java.io.*; -
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LF=c^9t  
af>3V(7  
public class FileAccessI implements Serializable{ C-#.RI7  
?eWJa  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 C6k4g75U2  
RandomAccessFile oSavedFile; ?n*fy  
long nPos; O3_B<Em  
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public FileAccessI() throws IOException X ]s"5ju|t  
{ 4]BJ0+|mT  
this("",0);  nP_=GI  
} x0x $  9  
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public FileAccessI(String sName,long nPos) throws IOException 3q~Fl=|.
o  
{ @InJ_
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oSavedFile = new RandomAccessFile(sName,"rw"); %Dyh:h  
this.nPos = nPos; Mvof%I  
oSavedFile.seek(nPos); NWISS  
} [ -12]3  
[h", D5  
*)%dXVf  
public synchronized int write(byte[] b,int nStart,int nLen) ?M"HX
u  
{ ZlM_m >,o  
int n = -1; 3}4#I_<$F@  
try{ @&:VKpu\  
oSavedFile.write(b,nStart,nLen); uX0 Bp8P  
n = nLen; p":@>v?  
} )k%M.{&bji  
catch(IOException e) u9}!Gq  
{ \dNhzd#  
e.printStackTrace (); h]}`@M"  
} :@e\'~7sH  
GN%<"I.  
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return n; w a.f![  
} |uQ[W17^N  
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} I=b'j5c  
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Ld~4nc$H8  
/* pX]21&F  
**SiteInfoBean.java ?H0m<jO8~  
*/ \*9Ua/H  
package NetFox; S-P{/;c@  
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public class SiteInfoBean { k!c7a\">{  
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\)GR\~z0h  
private String sSiteURL; //Site's URL @YNGxg~*g  
private String sFilePath; //Saved File's Path #fzw WP  
private String sFileName; //Saved File's Name 7<4xtK`+b  
private int nSplitter; //Count of Splited Downloading File [iXi\Ex  
4g'}h`kh  
TMtI^mkB:  
public SiteInfoBean() LO}z)j~W  
{//nSplitter的缺省值为5 4]u,x`6C  
//default value of nSplitter is 5 w=$'Lt!  
this("","","",5); JP_kQ  
} NCxn^$/+>9  
.]zw*t*  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) }
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{ 5])8qb/F  
sSiteURL= sURL;
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sFilePath = sPath; k?n]ZNlT  
sFileName = sName; U>1b9G"_  
this.nSplitter = nSpiltter; mR!rn^<l  
:OX$LCi  
>OTl2F}4 !  
} 0ZT 0
 
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public String getSSiteURL() PgTDjEo  
{ ktWZBQY  
return sSiteURL; @7]\y7D  
} vQcUaPm\$  
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b+_hI)T  
public void setSSiteURL(String value) e %&  
{ :=Nb=&lst  
sSiteURL = value; M(NH9EE  
} +yiU@K).0  
[}@n*D$  
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public String getSFilePath() fvO;lA>`  
{ BZ}`4W'  
return sFilePath; %-k(&T3&  
} O68bzi]  
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public void setSFilePath(String value) 4^`PiRGt  
{ +{'lZa  
sFilePath = value; v/ eB,p  
} 9Dy)nm^  
{DSyV:  
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public String getSFileName() t+j
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{ /jvOXS\M  
return sFileName; OoE9W  
} <TL])@da  
(26Bs':M~  
Z%KL[R}^w;  
public void setSFileName(String value) 4YBf ~Pp  
{
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sFileName = value; )4Bwt`VX  
} S'|lU@PCl  
:82?'aR  
\3L$I-]m  
public int getNSplitter() N:twq&[Y  
{ oO8]lHS?@  
return nSplitter; Z0{f  
} oy`3r5g  
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?{?
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public void setNSplitter(int nCount) d8D yv#gT  
{ >J9IRAm}sc  
nSplitter = nCount; JXlTN[O  
} 8 H,_vf  
} 2V 4`s'  
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Vn@A]Jx^  
/* Pu1GCr(  
**Utility.java >y&[BB7S6  
*/ bJANZn|H  
package NetFox; H&w(]PDh  
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public class Utility { o.p+j  
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3&O% &  
public Utility() "sdcP8])d  
{ <.;@ksCPW{  
vM5k4%D  
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} G[ ,,L  
?Ozk^#H[  
//线程睡眠 i:MlD5 F  
public static void sleep(int nSecond) lkI8{  
{ [^h/(a`  
try{ "tqS|ok.  
Thread.sleep(nSecond); unx;m$-c  
} 3S;>ki4(0  
catch(Exception e) muW`pm  
{ Bi'I18<  
e.printStackTrace (); ,oC={^l{  
} I:r($m  
} 9NJ=~Ub-  
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//日志 Iz 1*4@  
public static void log(String sMsg) Sr4dY`V*:z  
{ Uyz;U34 oI  
System.err.println(sMsg); R~U2/6V  
} ]|H]9mys98  
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Wh#os,U$  
public static void log(int sMsg) ,| $|kO/  
{ 40`9t Xn  
System.err.println(sMsg); l=Vowx.$2f  
} cP/F|uG5  
} MBnK&GS  
pE9aT5 L  
#p11D= @[  
/* s?4%<jz  
**TestMethod.java de3yP,  
*/ J
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package NetFox; s@*,r@<  
X; e`y:9  
;mCGh~?G  
public class TestMethod { +OV%B .  
l:>qR/|m  
WM~J,`]J  
public TestMethod() Fm-q=3  
{ ///xx/weblogic60b2_win.exe &!3VqHQ`  
try{ `
kaR@t  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); mtiO7w"M\7  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 'lQ  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 3j[w -Lfp  
fileFetch.start(); #n6FQ$l8m  
} *y":@T  
catch(Exception e){e.printStackTrace ();} %fexuy4  
wN/*|?`Z  
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} d()zW7}W  
=R"Eb1  
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public static void main(String[] args) b |o`Q7Hj  
{  0jip::x  
new TestMethod(); \4]zNV ~x  
} RE(=! 8lGR  
} f4A4  
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