http断点续传简单实现（java)

/* ?J6\?ct4  
**SiteFileFetch.java u\u6<[>P  
*/ @-XMox/  
package NetFox; LcGG~P|ML  
import java.io.*; vue=K  
import java.net.*; WTUC\}#E\  
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/m h #o  
public class SiteFileFetch extends Thread { ?y,z  
/<CgSW}  
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SiteInfoBean siteInfoBean = null; //文件信息Bean [y(<1]i-a  
long[] nStartPos; //开始位置 T)MZ`dM  
long[] nEndPos; //结束位置 N`+@_.iBX  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 $mn+  
long nFileLength; //文件长度 AhQsv.t   
boolean bFirst = true; //是否第一次取文件 Em/? 4&
 
boolean bStop = false; //停止标志 p`}G"DM  
File tmpFile; //文件下载的临时信息 .ViOf){U\  
DataOutputStream output; //输出到文件的输出流 !XT2'6nu  
B X Et]+Q  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） )u.%ycfeV  
public SiteFileFetch(SiteInfoBean bean) throws IOException %+L3Xk]m'  
{ :@^
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siteInfoBean = bean; pW-aX)\DR  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); BP8jReX^  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 3Cg0^~?6-  
if(tmpFile.exists ()) j0A9;AP;;C  
{ CMU\DO  
bFirst = false; i:
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read_nPos(); c='uyx  
} 2@:Ztt6~  
else jB3Rue:+g  
{ SlD7 \X&~  
nStartPos = new long[bean.getNSplitter()]; N==Y]Z$G  
nEndPos = new long[bean.getNSplitter()]; W4]jx]  
} w %R=kY)o  
%( #kJZ  
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} ah15,<j  
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public void run() 8WLBq-]G  
{ oTk?a!Q  
//获得文件长度 8 G:f[\^  
//分割文件 O{wt0 \P  
//实例FileSplitterFetch 5
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//启动FileSplitterFetch线程 IV|})[n*  
//等待子线程返回 A8j$c~  
try{ @^,9O92l  
if(bFirst) /N=M9i
\;  
{ SD]rYIu+  
nFileLength = getFileSize(); y#-~L-J_R  
if(nFileLength == -1) quiX"lV(  
{ >"pHk@AWK  
System.err.println("File Length is not known!"); e{}vT$-  
} P@8S|#LpZ  
else if(nFileLength == -2) <MgC7S2I  
{ LmjGU[L,@  
System.err.println("File is not access!"); SH;:bLk_  
} 8P*wt'Q$  
else ~~{+?v6B]  
{ ;I]$N]8YI  
for(int i=0;i<nStartPos.length;i++) o*:D/"gb  
{ b$=c(@]  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); -
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} ,W5!=\Gg(  
for(int i=0;i<nEndPos.length-1;i++) z;Dc#SZnO(  
{ lBNB8c0e"{  
nEndPos = nStartPos[i+1]; '?qI_LP?  
} i`7:^v;  
nEndPos[nEndPos.length-1] = nFileLength; UUqA^yJ  
} }/M`G]wT#  
} ?Y_!Fr3V  
lh*!f$2~  
(dAE  
//启动子线程 rz.`$  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; WU{9lL=  
for(int i=0;i<nStartPos.length;i++) |/~ISB  
{ pU[5f5_  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 3(=QY)  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), jDCf]NvOPM  
nStartPos,nEndPos,i); $B?IE#7S4  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); `WlQ<QEi  
fileSplitterFetch.start(); ]DLs'W;)  
} h[r)HX0hA  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), :djbZ><  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); :;N2hnHoG  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", V7$-4%NL  
nEndPos = " + nFileLength); c!J|vRA5  
// fileSplitterFetch[nPos.length-1].start(); ->5[C0: ]  
f- ~]  
F3&:KZ!V&m  
//等待子线程结束 TJz} 8-#t  
//int count = 0; $(&+NJ$U$  
//是否结束while循环 UaM&/K9  
boolean breakWhile = false; _t@9WA;+\  
aHBM9%gV  
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while(!bStop) A\QrawBp0l  
{ =$
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write_nPos(); ?xb2jZ/0X  
Utility.sleep(500); tW"s^r=95  
breakWhile = true; lfyij[6q+  
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for(int i=0;i<nStartPos.length;i++) 7!^Zsp^+  
{ KBwY _  
if(!fileSplitterFetch.bDownOver) ]
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{ z_A34@a  
breakWhile = false; `k~w 14~w  
break; o;'-^ LJ  
} z i3gE$7  
} Jp +h''t  
if(breakWhile) :}[D;cx  
break; 9 N9Q#o$!.  
aIklAj)=  
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//count++; [A#>G4a<  
//if(count>4) 7WEoyd  
// siteStop(); t[X,m]SX  
} &ej|DM6  
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System.err.println("文件下载结束！"); %^(} fu  
} >^Y)@J
 
catch(Exception e){e.printStackTrace ();} h#]LXs  
} \\$wg   
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//获得文件长度 Y$nI9  
public long getFileSize() .oz(,$CS"  
{ fx= %e  
int nFileLength = -1; `;z;=A*  
try{ V;1i/{  
URL url = new URL(siteInfoBean.getSSiteURL());  4B'-tV  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); =xRxr@  
httpConnection.setRequestProperty("User-Agent","NetFox"); +3o 4KB}  
!l~3K(&4  
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int responseCode=httpConnection.getResponseCode(); `bcCj~j  
if(responseCode>=400) c$~J7e6$  
{ x}H%NzR  
processErrorCode(responseCode); m
9Hdg^L  
return -2; //-2 represent access is error 77~l~EX  
} K]yUPx  
`d!~)D  
KAm$^N5  
String sHeader; x*0mmlCb  
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+V/mV7FK  
for(int i=1;;i++) 6Y/TqI[   
{ 6|ENDd[  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); A3zO&4f ]  
//Utility.log(in.readLine()); `sJv?  
sHeader=httpConnection.getHeaderFieldKey(i); Wj\< )cH]  
if(sHeader!=null) x).`nZ1  
{ bTc'E#  
if(sHeader.equals("Content-Length")) L+TM3*a*  
{ zq4)Uab*  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); znu[i&\=  
break; r+;AEN48  
} JsbH'l  
} (Q ~<>  
else ZIvP?:=!  
break; 6D1tRo  
} {b90c'8?a  
} i-31Cxb  
catch(IOException e){e.printStackTrace ();} 8ubb~B;  
catch(Exception e){e.printStackTrace ();} :qO)^~x  
6%2\bI.#  
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Utility.log(nFileLength); O -N> X  
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return nFileLength; K 6HH_T  
} =Btmi  
c`4i#R
 
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//保存下载信息（文件指针位置） 9$e6?<`(Y  
private void write_nPos() ]6TX)1  
{ J)a^3>  
try{ /_CSRi&
 
output = new DataOutputStream(new FileOutputStream(tmpFile)); 7s.vJdA]6  
output.writeInt(nStartPos.length); A_<1}8{L  
for(int i=0;i<nStartPos.length;i++) Q^\f,E\S  
{ :H
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// output.writeLong(nPos); h6C:`0o  
output.writeLong(fileSplitterFetch.nStartPos); 7="I;  
output.writeLong(fileSplitterFetch.nEndPos); !nyUAZ9 :  
} iXFN|ml  
output.close(); p/.[cH  
} Acx
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catch(IOException e){e.printStackTrace ();} ro*$OLc/  
catch(Exception e){e.printStackTrace ();} O7GJg;>?  
} Hp?uYih0  
8i'EO6  
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//读取保存的下载信息（文件指针位置） %!QY:[  
private void read_nPos() ;+iw?"  
{ SoJ'y
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try{ =9'px3:'WR  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); `]\:%+-  
int nCount = input.readInt(); I85bzzZB  
nStartPos = new long[nCount]; R.B3  
nEndPos = new long[nCount]; |_
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for(int i=0;i<nStartPos.length;i++) _^cFdP)8|  
{ 6o^sQ(]  
nStartPos = input.readLong(); !ie'}|c  
nEndPos = input.readLong(); e-/+e64Q@  
} /J`ZO$  
input.close(); @$%[D`Wa<  
} 6I,4 6 XZ-  
catch(IOException e){e.printStackTrace ();} ^Q""N<  
catch(Exception e){e.printStackTrace ();} BA cnFO  
} $Hbd:1%i {  
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[^GXHE=  
private void processErrorCode(int nErrorCode) TBp$S=_**  
{  rytaC(  
System.err.println("Error Code : " + nErrorCode); WnZn$N.  
} :OvTZ ?\  
;L.RfP"5<  
!w-`:d?  
//停止文件下载 YR} P;  
public void siteStop() (jB_uMuS  
{ -Rz%<`  
bStop = true; biw2f~V  
for(int i=0;i<nStartPos.length;i++) g_F-PT>($  
fileSplitterFetch.splitterStop(); +a
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} p{k^)5CR/  
} vynchZ+g]  
//负责部分文件的抓取 qz2j55j   
**FileSplitterFetch.java }m0hq+p^  
*/ xh raf1v3\  
package NetFox; `L1lGlt  
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import java.io.*; o$,Dh?l  
import java.net.*; K{#1O=Gi  
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public class FileSplitterFetch extends Thread { /WX 0}mWu  
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String sURL; //File URL #3m7`}c  
long nStartPos; //File Snippet Start Position 't:s6  
long nEndPos; //File Snippet End Position -32?]LN}  
int nThreadID; //Thread's ID 3om4q2R  
boolean bDownOver = false; //Downing is over w`;>+_ E7  
boolean bStop = false; //Stop identical b`Agb<x"  
FileAccessI fileAccessI = null; //File Access interface /,cyp.  
AD/7k3:  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException jWL;ElM'  
{ :Z'q1kW@"  
this.sURL = sURL; 4RYvI!
 
this.nStartPos = nStart; ,V}Vxq3  
this.nEndPos = nEnd; .*>pD/  
nThreadID = id; v)AadtZ0d  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 $IU|zda8  
} gcNpA?mC|u  
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;x=r.3OQy  
public void run() }qhNz0*  
{ 1FQ_`wF4  
while(nStartPos < nEndPos && !bStop) auKGm:  
{ +zup+=0e  
'7Aj0U(  
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try{ uY~xHV_-  
URL url = new URL(sURL); v%%;Cp73  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); XdR^,;pWE  
httpConnection.setRequestProperty("User-Agent","NetFox"); [C TR8  
String sProperty = "bytes="+nStartPos+"-"; OY>0qj  
httpConnection.setRequestProperty("RANGE",sProperty); 'K0=FPB/@  
Utility.log(sProperty); 4M4oI .  
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InputStream input = httpConnection.getInputStream(); =*Ad  
//logResponseHead(httpConnection); l~v BA$,  
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byte[] b = new byte[1024]; 9uL="z$\  
int nRead; yF#:*Vz>  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) O]nZr  
{ WKwU:im  
nStartPos += fileAccessI.write(b,0,nRead); m{)F9F  
//if(nThreadID == 1) \HsrUZ~  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); [,1\>z|&  
} 0,x<@.pW  
EN!Q]O|  
:',Q6j(s  
Utility.log("Thread " + nThreadID + " is over!"); 7P2?SW^
 
bDownOver = true; +UTs2*H/^  
//nPos = fileAccessI.write (b,0,nRead); u3>Dvl@  
} s{]2~Z^2od  
catch(Exception e){e.printStackTrace ();} V9"?}cR/W;  
} tLzX L*  
} TnvX&Y'  
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ee=d*)  
//打印回应的头信息 <&$:$_ah  
public void logResponseHead(HttpURLConnection con) a &89K  
{ &74*CO9B9  
for(int i=1;;i++) qU) pBA
 
{ QE8aYPSFf  
String header=con.getHeaderFieldKey(i); ]_ON\v1  
if(header!=null) :$#";t|  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); jPjFp35;zb  
Utility.log(header+" : "+con.getHeaderField(header)); Td`0;R'<}c  
else dGrm1w  
break; [MkXQwY  
} 5ma*&Q8+  
} A]FjV~PB  
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e
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public void splitterStop() o1"-x  
{ zeZ}P>C  
bStop = true; O\(0{qu  
} {J}Zv5  
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} Y_}DF.>I P  
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/* O'G
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**FileAccess.java Ba9le|c5  
*//文件访问(定位，写) X R =^zp?  
package NetFox; @\=%M^bx  
import java.io.*; G%V*+Ond  
8u401ddg  
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public class FileAccessI implements Serializable{ pErre2fS  
,MtN_V-  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 {M5[gr%  
RandomAccessFile oSavedFile; dz6i~&  
long nPos; \.R+|`{tf  
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public FileAccessI() throws IOException .!\NM&E  
{ (oYM}#Q  
this("",0); V=@M!;'<  
} :d7tzYT ^  
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public FileAccessI(String sName,long nPos) throws IOException DKjkO5R\  
{ ZS-O,[  
oSavedFile = new RandomAccessFile(sName,"rw"); 5F8sigr/h  
this.nPos = nPos; bOi`JJ^  
oSavedFile.seek(nPos); {!B^nCSL  
}
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public synchronized int write(byte[] b,int nStart,int nLen) yH<^txNF  
{ u_C/Y[ik  
int n = -1; /uc*V6Xd (  
try{ ?E@9Nvr  
oSavedFile.write(b,nStart,nLen); ,~!rn}MI<  
n = nLen; O~r.sJ}  
} +~6gP!  
catch(IOException e) Wm5/>Cu,  
{
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e.printStackTrace (); @q?zh'@;  
} O>=D1no*  
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return n; .H,wdzg)  
} `XwFH#_  
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} FQbF)K~e  
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/* xp395ub6  
**SiteInfoBean.java .@Z-<P"  
*/ PKT/U^2X]  
package NetFox; ^<0azza/(  
L{hP&8$k  
7>g^OE f  
public class SiteInfoBean { PD$gW`V  
PXZZPW/  
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private String sSiteURL; //Site's URL (f^K\7HM  
private String sFilePath; //Saved File's Path n$*'J9W~  
private String sFileName; //Saved File's Name W2F %E  
private int nSplitter; //Count of Splited Downloading File :EISms  
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public SiteInfoBean() Z
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{//nSplitter的缺省值为5 pU4B6
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//default value of nSplitter is 5 k{/2vV[`]  
this("","","",5); {xm^DT  
} +gG6(7&+=  
V@0Z\&  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) S C8r.
  
{ 'J&&F2O%  
sSiteURL= sURL; v2>.+Eh#  
sFilePath = sPath; \}0J%F1  
sFileName = sName; OPp>z0p%6X  
this.nSplitter = nSpiltter; -r9G5Z!|n  
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} ?fB}9(
6  
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public String getSSiteURL() KGCm@oy  
{ tBNkVh(c  
return sSiteURL; `!?SA<a:  
} FcnSO0G%  
Sm
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public void setSSiteURL(String value) s6k,'`.  
{ 6~Y-bn"%D5  
sSiteURL = value; sK~d{)+T  
} &J~vXk: !  
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[KIK}:  
public String getSFilePath() -G<$wh9~3  
{ l4o
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return sFilePath; @\,WJmW  
} V j\1HQ  
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public void setSFilePath(String value) g{&a|NU^  
{ H\tz"<*``  
sFilePath = value; B
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} zi~_[l-  
"Jw6.q+  
;eznONNF  
public String getSFileName() Dp 
0   
{ _w+ix9Fr?  
return sFileName; 2| u'J  
} 9/OB!<*V|  
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!br0s(|  
public void setSFileName(String value) ?MevPy`H  
{ &DdFK.lt  
sFileName = value; |I7-7d-;/  
} =/@c9QaVB  
z= p
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public int getNSplitter() jq{rNxdGx  
{ ,^MA,"8  
return nSplitter; "x&hBJ  
} e-;$Iv  
7<V(lX.{  
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public void setNSplitter(int nCount) m|<j9.iJ  
{ jIx5_lFe  
nSplitter = nCount; cT abZc  
} s8T}ah!  
} OHeVm-VC  
@&;y0N1xo  
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/* AY['!&T  
**Utility.java [xT2c.2__J  
*/ mjbr}9  
package NetFox; nA%H`/O{  

?C   
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public class Utility { lJ!+n<K+  
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public Utility() T_CYSS|fX  
{ <7TE[M'  
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1P&XG@  
} \;x+KD  
(l :;p&[  
//线程睡眠 %RgCU$s[>  
public static void sleep(int nSecond) =BpX;n<  
{ 9aT#7B  
try{ ^+cf  
Thread.sleep(nSecond); UahFs  
} X_XeI!,b  
catch(Exception e) I3o6ym-i  
{ RWf4Wh?d  
e.printStackTrace (); :%qJAjR&  
} +hg|!SS@5  
} g]O"l?xx1D  
HErTFY+vC  
//日志 %76N$`{u  
public static void log(String sMsg) U]Q2EL\%  
{ w~sr2;rp<  
System.err.println(sMsg); Dt\F]\6sd  
} uZ*;
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:i+Tf~k{  
qCOe,$\1/  
public static void log(int sMsg) L}CjC>R!  
{ cMxTv4|wui  
System.err.println(sMsg); OL&ku &J_  
} L2Uk/E  
} TGu`r>N51  
W@jBX{k  
zZDa71>  
/* x]6OE]]8L  
**TestMethod.java Zuod1;qIh  
*/ aB~?Y+m  
package NetFox; ;,n{6`  
H `Fe|6I&  
'cJHOd  
public class TestMethod {
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-sl] funRy  
7u-o7#,X2  
public TestMethod() !Q
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{ ///xx/weblogic60b2_win.exe #
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try{ GQO}E@W6C  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); io^^f|  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); J
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SiteFileFetch fileFetch = new SiteFileFetch(bean); [5^"U+`{x  
fileFetch.start(); z 7OTL<h  
} d(zBd=;  
catch(Exception e){e.printStackTrace ();} W#E-vi+l  
TG'_1m*$  
^B~z .F i  
} g|8G!7O  
ZFh2v]|!  
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public static void main(String[] args) 4M'y9(  
{ ax&,  
new TestMethod(); $5T3JOFz  
} z/aZ
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} !_)*L+7f_  
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