http断点续传简单实现（java)

/* A"ApWJ3  
**SiteFileFetch.java ixJ%wnz  
*/ 1HPYW7jk@"  
package NetFox; <e)5$Aj  
import java.io.*; <?h
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import java.net.*; yCC.j%@  
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public class SiteFileFetch extends Thread { y{{7)G  
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SiteInfoBean siteInfoBean = null; //文件信息Bean %VZQX_  
long[] nStartPos; //开始位置 A 9\]y%!  
long[] nEndPos; //结束位置 uv>T8(w  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Vm+e%  
long nFileLength; //文件长度 vQK*:IRKK  
boolean bFirst = true; //是否第一次取文件 X=_`$ 0  
boolean bStop = false; //停止标志 V)Oj6nD]  
File tmpFile; //文件下载的临时信息 OZ,%T9vP  
DataOutputStream output; //输出到文件的输出流 !LDuCz -  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） PH$fDbC8  
public SiteFileFetch(SiteInfoBean bean) throws IOException $d:>(_p=A  
{ "lU%Pm]>  
siteInfoBean = bean; GP|G[  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ur*@TIvD  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); (`nn\)  
if(tmpFile.exists ()) +T\c<lJ9  
{ B{`4"uEb$G  
bFirst = false; ea7l:(C  
read_nPos(); H#zsk*=QD  
} Dl/Jlsd@  
else 7=Vs1TVc  
{ ;}/@ar7s3  
nStartPos = new long[bean.getNSplitter()]; "j(?fVx  
nEndPos = new long[bean.getNSplitter()]; r0 mXRZC  
} <]9%Pm#X  
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} q>JW$8  
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public void run() yDk|ad|  
{  ^##tk
  
//获得文件长度 lL6bIjf  
//分割文件 dM|&Y6
  
//实例FileSplitterFetch 7*D*nY4+  
//启动FileSplitterFetch线程 MJxTzQE  
//等待子线程返回 *cNqgw#\qL  
try{ XnBpL6"T`  
if(bFirst) Ry5/O?QL  
{ `F)Q=  
nFileLength = getFileSize(); <X
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if(nFileLength == -1)  3)5Gzn  
{ 6L`{oSX!  
System.err.println("File Length is not known!"); wTT_jyH)  
} g`(' k5=  
else if(nFileLength == -2) =SY5E{`4p  
{ aN\psg  
System.err.println("File is not access!"); yW3X<  
} X[F<sxw  
else XI>|"*-l  
{ 
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for(int i=0;i<nStartPos.length;i++) 2d%j6D  
{ IIn0w2:i  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); .Fdqn?c|+  
} Q"2t:  
for(int i=0;i<nEndPos.length-1;i++) F.nJXZnJ  
{ UD0via  
nEndPos = nStartPos[i+1]; [#}A]1N  
} }4 p3m]  
nEndPos[nEndPos.length-1] = nFileLength; .Vy*p")"  
} Y;JPr  
} >o\s'i[  
fWr6f`de  
}=d]ke9_  
//启动子线程 +Xa^3 =B  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; t")+L{  
for(int i=0;i<nStartPos.length;i++) %&D,|Yl6  
{ Cpyv@+;D  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), hJ)>BeH0  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 7.-g=R
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nStartPos,nEndPos,i); vSu|!Xb]  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos);  pt`^4}  
fileSplitterFetch.start(); K2=`.  
} pI__<  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), l?_h(Cq<  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); '/Y D$*,  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", OK=lp4X  
nEndPos = " + nFileLength); 8XwZJ\5  
// fileSplitterFetch[nPos.length-1].start(); "X\|!Mxh  
f^ q0#+k)  
.I6:iB  
//等待子线程结束 }7`HJ>+m)H  
//int count = 0; H<^*V8J 'w  
//是否结束while循环 41pk )8~pt  
boolean breakWhile = false; ]e*Zx;6oi  
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while(!bStop) D)yCuw{M:  
{ @y{i.G  
write_nPos(); %SWtE5HZQq  
Utility.sleep(500); [31vx0$_p  
breakWhile = true; ^qs{Cf$  
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for(int i=0;i<nStartPos.length;i++) W%/lBkP  
{ 50s)5G#  
if(!fileSplitterFetch.bDownOver) ^H0`UKE  
{ F4!,8)}  
breakWhile = false; ^uU'Qc4S=  
break; 9t`Z_HwdCb  
} A5d(L4Q]a(  
} [dsz
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if(breakWhile) 3YtFO;-  
break; ;n-)4b]\  
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//count++; SUSam/xeg"  
//if(count>4) <"SDU_<xG  
// siteStop(); <tT*.n
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} -3YsrcJi  
|sM#nhxK  
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System.err.println("文件下载结束！"); Gi<ik~  
} 6 (:^>@  
catch(Exception e){e.printStackTrace ();} X>i`z  
} Ch`nDIne  
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9J"Y   
//获得文件长度 r#Pkhut  
public long getFileSize() 410WWR&4_  
{ 8J&K_JC^  
int nFileLength = -1; m,zZe}oJ  
try{ o_2mSD
!  
URL url = new URL(siteInfoBean.getSSiteURL()); }]-SAM  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); c$<7&{Pb  
httpConnection.setRequestProperty("User-Agent","NetFox"); =r<0l=  
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int responseCode=httpConnection.getResponseCode(); Y0kDHG  
if(responseCode>=400) *`}4]OGv.  
{ {{FA"NW  
processErrorCode(responseCode); -
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return -2; //-2 represent access is error VrV* -J'  
} NW}kvZ  
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String sHeader; ` ]*KrY  
*{5L*\AZ  
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for(int i=1;;i++) ObDcNq/b!  
{ _$OhV#LKG  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); #}^kMD >  
//Utility.log(in.readLine()); Y(>]7  
sHeader=httpConnection.getHeaderFieldKey(i); {.W$<y (j7  
if(sHeader!=null) e`1,jt'  
{ %cM2;a=2  
if(sHeader.equals("Content-Length")) !ul)e;a  
{ Sb&sW?M  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); xg'FC/1LD  
break; T=8>0D^v5  
} b";w\H  
} st;.Po[h  
else Fm\ h883\  
break; !_+LmBd G  
} %ZV a{Nc  
} w!Nt
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catch(IOException e){e.printStackTrace ();} ~jd:3ip+!  
catch(Exception e){e.printStackTrace ();} Qp{rAAC:  
>
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Utility.log(nFileLength); AT^?PD_  
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q  
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return nFileLength; Dk#$PjcRE  
} Jo1=C.V`Y  
\ H#zRSbZ  
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//保存下载信息（文件指针位置） "FC;k >m  
private void write_nPos() T-=sC=sS,  
{ q9-=>  
try{ )Cuc]>SC  
output = new DataOutputStream(new FileOutputStream(tmpFile)); j)Z3m @Ii5  
output.writeInt(nStartPos.length); YoD1\a|  
for(int i=0;i<nStartPos.length;i++) cad%:%p  
{ Ez^U1KKOE7  
// output.writeLong(nPos); /*Z,i&eC  
output.writeLong(fileSplitterFetch.nStartPos); xbex6i"ZE  
output.writeLong(fileSplitterFetch.nEndPos); )j6VROt  
} DUg  
output.close(); ]R^?Pa1Te4  
} }U$Yiv  
catch(IOException e){e.printStackTrace ();}  A_: Bz:  
catch(Exception e){e.printStackTrace ();} YQ>M&lnQ<  
} E<>Ev_5>  
6:i(<7  
#UH|,>W6  
//读取保存的下载信息（文件指针位置） Q!Rknj 2  
private void read_nPos() 3=!\>0;E-  
{ &3VR)Bxn  
try{ o.5w>l!9K  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); sL;qC\S  
int nCount = input.readInt(); c ?mCt0Cg  
nStartPos = new long[nCount]; Bb];qYuCO  
nEndPos = new long[nCount]; .bbl-a/ 3  
for(int i=0;i<nStartPos.length;i++) -yt[0  
{ ukV1_QeN[  
nStartPos = input.readLong(); vJkY  
nEndPos = input.readLong(); dBY,&=T
4p  
} l -~HY*  
input.close(); >JVZ@ PV H  
} \D BtU7"v  
catch(IOException e){e.printStackTrace ();} g7k|Ho-W  
catch(Exception e){e.printStackTrace ();} (3C6'Wt  
} 3O<:eS~  
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private void processErrorCode(int nErrorCode) ))}w;w  
{ 1btQ[a6j  
System.err.println("Error Code : " + nErrorCode); oB8u[!  
} iXtar;%  
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=LHE_ AA  
//停止文件下载 q4$zsw  
public void siteStop() sHO6y0P  
{ ml7]sN(  
bStop = true; EBS04]5ul  
for(int i=0;i<nStartPos.length;i++) $L>tV='  
fileSplitterFetch.splitterStop(); e!*d(lHKos  
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}6}Gj8Nb  
} 0qSd#jO  
}
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//负责部分文件的抓取 y5>859"h  
**FileSplitterFetch.java Z
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*/ :
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package NetFox; ny17(Y =  
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import java.io.*; fB[I1Z  
import java.net.*; O<l_2?S1  
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public class FileSplitterFetch extends Thread { j,QeL  
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String sURL; //File URL *+h2,Z('a  
long nStartPos; //File Snippet Start Position |cL'4I>b9  
long nEndPos; //File Snippet End Position tF SO"  
int nThreadID; //Thread's ID %..{c#V  
boolean bDownOver = false; //Downing is over H27_T]\  
boolean bStop = false; //Stop identical R[5*]$(b  
FileAccessI fileAccessI = null; //File Access interface A:F*Y%ZW  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException h9c54Ux  
{
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this.sURL = sURL; 8D[P*?O  
this.nStartPos = nStart; N~L3 9  
this.nEndPos = nEnd; 6rMGlzuRo  
nThreadID = id; D]v=/43  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 }s{RW<A  
} OO
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public void run() y/rmxQtP  
{ qsn
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while(nStartPos < nEndPos && !bStop) Fy8KZWim  
{ fk,[`n+  
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,  
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try{ =ZjF5,@  
URL url = new URL(sURL); x3O$eKy\|5  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); @U'I_`LL  
httpConnection.setRequestProperty("User-Agent","NetFox"); %CJgJ,p
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String sProperty = "bytes="+nStartPos+"-"; TO.?h!  
httpConnection.setRequestProperty("RANGE",sProperty);
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Utility.log(sProperty); @ae;&  
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InputStream input = httpConnection.getInputStream(); ECqcK~h#E  
//logResponseHead(httpConnection); -qz;  
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byte[] b = new byte[1024]; 5an#,vCn{  
int nRead; L31B:t^  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) PpX=~Of~  
{ 'S\YNLqQ  
nStartPos += fileAccessI.write(b,0,nRead); fgYdKv8  
//if(nThreadID == 1) ST1PSuC~  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); _x_om#~n  
} EaGh`*"w(7  
5hak'#2  
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Utility.log("Thread " + nThreadID + " is over!"); Z?|\0GR+`5  
bDownOver = true; rr>*_67-:  
//nPos = fileAccessI.write (b,0,nRead); 1a4 [w  
} 2[: *0 DV#  
catch(Exception e){e.printStackTrace ();} / 2>\Z(  
} znv2
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} d-nqV5  
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//打印回应的头信息 O0Y/y2d  
public void logResponseHead(HttpURLConnection con) )3PQ|r'  
{ xTNWT_d  
for(int i=1;;i++)
#n5q$  
{ ?khwupdi  
String header=con.getHeaderFieldKey(i); A$.woE@  
if(header!=null) [xq"[*Evv  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 6=a($s!   
Utility.log(header+" : "+con.getHeaderField(header)); 26un=  
else 0@z=0}0Z  
break; w%;Z`Xn&u  
} }@Lbvaa  
} vUh.ev0  
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public void splitterStop() zk= 3L} C  
{ T<kyxbjR  
bStop = true; JTB
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} |uVhfD=NG  
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} Cp(,+dD  
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/* /Hb'3,jN  
**FileAccess.java '^"6EF.R  
*//文件访问(定位，写) 3D70`u  
package NetFox; afOb-G$d=  
import java.io.*; v+dt1;  
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public class FileAccessI implements Serializable{ 1V(tt{  
;=.VKW%U  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 E&r*[;$  
RandomAccessFile oSavedFile; sr,8zKM)  
long nPos; //*>p  
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public FileAccessI() throws IOException aY7kl  
{ P[-2^1P
"  
this("",0); 5\/h3i"I  
} j;@7
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public FileAccessI(String sName,long nPos) throws IOException o mstJ9  
{ Ga0= G&/  
oSavedFile = new RandomAccessFile(sName,"rw"); #"% ]1={b  
this.nPos = nPos; jz(}P8  
oSavedFile.seek(nPos); =;Gy"F1 dp  
} "pTyQT9P  
v&oE!s#  
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public synchronized int write(byte[] b,int nStart,int nLen) 2^N 4(
 
{ d[;=X.fZ2  
int n = -1; )TV4OT#  
try{ ma.yI};
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oSavedFile.write(b,nStart,nLen); ;(M`Wy]2  
n = nLen; vy\;#X!  
} -ZqN~5>j)  
catch(IOException e) *fVs|  
{ ~yz7/?A)TS  
e.printStackTrace (); PW)XDo7  
} vhiP8DQ  
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return n; }wzU<(Rx  
} 7Wub@Mp  
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} QZ(se  
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p\5DW'  
/* O@St^o*A}  
**SiteInfoBean.java 4RYK9=NH  
*/ Mo`7YS-Y  
package NetFox; * Zb-
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[|<2BQX  
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public class SiteInfoBean { }|>mR];  
l?E7'OEF:  
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private String sSiteURL; //Site's URL Q.:SIBP  
private String sFilePath; //Saved File's Path Yy]^_,r  
private String sFileName; //Saved File's Name D/pc)3Ofe  
private int nSplitter; //Count of Splited Downloading File #MYhKySku  

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public SiteInfoBean() $8#zPJR&  
{//nSplitter的缺省值为5 z;`o>Ja2  
//default value of nSplitter is 5 {~7VA  
this("","","",5); KsI[  
} ((L=1]w  
"1P8[  
#:"F-3A0  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 7+';&2M)n~  
{ c0M=T  
sSiteURL= sURL; afY~Y?PJ<  
sFilePath = sPath; sE7!U|  
sFileName = sName; L ;5uB2  
this.nSplitter = nSpiltter; R /J@XP  
F.ml]k&(m  
n]G!@-z  
} ;QbMVY  
m }I@:s2  
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public String getSSiteURL() I\J^@&
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{ _IiTB  
return sSiteURL; {p&M(
W]  
} *cn,[  
],{b&\  
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public void setSSiteURL(String value) !C>}j* 4  
{ "{-jZdq'  
sSiteURL = value; *{|{T_H:  
} mk#xbvvG  
&t1?=F,]  
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public String getSFilePath() e\%emp->  
{ |#^##^cF/  
return sFilePath; |f+|OZY  
} Lk{ES$  
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public void setSFilePath(String value) sCG[gshq  
{ $oKT-G  
sFilePath = value; r}ZL{uWMW  
} /y/O&`X(  
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public String getSFileName() F&?&8.  
{ =8BMCedH|  
return sFileName; $S{B{FK  
} -7^?40A  
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public void setSFileName(String value) lt 74`9,f  
{ ()L[l@m  
sFileName = value; [:Kl0m7  
} Q; DN*  
7,Tg>,%Q  
%\OG#36  
public int getNSplitter() }c/p+Wo  
{ Uz(Sv:G  
return nSplitter; 6^ UQ{P1;  
} 6;rJIk@Fx=  
z3RD*3b  
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public void setNSplitter(int nCount) m]t`;lr<  
{ P~Ss\
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nSplitter = nCount; 4LY kK/:  
} -yKx"Q9F  
} yhnhORSY;  
6
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/* zq ;Y
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**Utility.java ^~iu),gu  
*/ .{,
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package NetFox; yTj!(C  
.Y!]{c  
p'PHBb8I  
public class Utility { aH6{_eY  
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9I3vW]0x[  
public Utility() ,S.<qmf  
{ @lvvI<U  
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8}9B*m  
} &fH;A X.  
tNsiokOm  
//线程睡眠 <\i}zoPO  
public static void sleep(int nSecond) v
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{ vFuf{ @P  
try{ Z)=S. )  
Thread.sleep(nSecond); ')!+>b(P  
} F$[1KjS  
catch(Exception e) 2flgfB}2k  
{ )3h%2C1uM  
e.printStackTrace (); M'Fa[n*b?!  
} 3Yu1ZuIR  
} A6D.bJ)  
_^{!`*S  
//日志 p6=L
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public static void log(String sMsg) =3KK/[2M  
{ .9r+LA{  
System.err.println(sMsg); ;IklS*p]  
} V5
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cb ICO  
public static void log(int sMsg) +n#(QOz  
{ %Ot2bhK;  
System.err.println(sMsg); IB~`Ht8 b  
} uL`6}0  
} >eF4YZ"  
\1k(4MWd  
v]`}T/n  
/* VU~ R  
**TestMethod.java @y3u'Y,B  
*/ AawK/tfs  
package NetFox;  U~%V;*|4  
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i:8g3|JfMe  
public class TestMethod { gDY+'6m;  
p72:oX\QI  
/`d|W$vN  
public TestMethod() ARcPHV<(2  
{ ///xx/weblogic60b2_win.exe A\{dq:  
try{ L`$m<9w'  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 2L=+z1%I  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 6O|B'?]Pf  
SiteFileFetch fileFetch = new SiteFileFetch(bean);
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fileFetch.start(); p1zT]  
} <>!Y[Xr^  
catch(Exception e){e.printStackTrace ();} 8&q|*/2  
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<Q-Y$ ^\  
} hYm$Sx(=  
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public static void main(String[] args) p#-;u1-B  
{ 41\r7 BS  
new TestMethod(); j/I^\Ms  
} #g)$m}tv?  
} l`#XB:#U  
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