http断点续传简单实现（java)

/* Mi74Xl i  
**SiteFileFetch.java AZwa4n}"  
*/ oT->^4WY  
package NetFox; ^saM$e^c:  
import java.io.*; \!wh[qEQ\  
import java.net.*; $l"MXxx5I  
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public class SiteFileFetch extends Thread { Wk[)+\WQ?  
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SiteInfoBean siteInfoBean = null; //文件信息Bean d_T<5Hin  
long[] nStartPos; //开始位置 t w!.%_1^  
long[] nEndPos; //结束位置 :t>Q:mX(N  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 }17bV, t  
long nFileLength; //文件长度 4$Pr|gx  
boolean bFirst = true; //是否第一次取文件 #!d]PH746  
boolean bStop = false; //停止标志 b-nYxd
  
File tmpFile; //文件下载的临时信息 QUp?i  
DataOutputStream output; //输出到文件的输出流 *<k&#D"m  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） !!+Da>  
public SiteFileFetch(SiteInfoBean bean) throws IOException t/ eo]  
{ PYieD}'  
siteInfoBean = bean; +*a7GttU  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); IJIQ" s  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); S'@=3)  
if(tmpFile.exists ()) q^6N+^}QN  
{ Wp
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bFirst = false; *w 21U!  
read_nPos(); |EeBSRAfe  
} o7arxo\  
else @dV9Dpu  
{ sVoR?peQ  
nStartPos = new long[bean.getNSplitter()]; ;
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nEndPos = new long[bean.getNSplitter()]; 1;`Fe":;vC  
} CJA+v-  
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} YFqZe6g0$  
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public void run() (H-cDsh;c  
{ {]["6V6W  
//获得文件长度 *(nJX.7  
//分割文件 +-P<CCvWz  
//实例FileSplitterFetch i[_|%'p  
//启动FileSplitterFetch线程 o=mo/N4  
//等待子线程返回 pK"&QPv  
try{ D1ZC&B_}-  
if(bFirst) /.v_N%*-v  
{ :rL?1"  
nFileLength = getFileSize(); uk6g s)qxC  
if(nFileLength == -1) %,;gP.dh7  
{ %/%gMRXG2  
System.err.println("File Length is not known!"); ^S=cNSpC  
} ~oFh>9u  
else if(nFileLength == -2) eP?~-#  
{ +"Ub/[J{G1  
System.err.println("File is not access!"); +!xu{2!  
} V4
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else sDAK\#z  
{ k}<<bm*f  
for(int i=0;i<nStartPos.length;i++) 2_N/wR#=&  
{ en%B>]QI  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); J7m`]!*t  
} ?\M)WDO  
for(int i=0;i<nEndPos.length-1;i++) 0Jg+sUs{  
{ SS0_P jKz  
nEndPos = nStartPos[i+1]; J% AG`  
} idz9YpW  
nEndPos[nEndPos.length-1] = nFileLength; BPiiexTV9  
} E[*0Bo]  
} 7vq DZg  
Z>h{` X\2  
%r P !  
//启动子线程 S;h&5.p  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 
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for(int i=0;i<nStartPos.length;i++) ZR6&AiL(Bj  
{ %HVD^. V  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), l# BZzJ?~  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), nj"m^PmWo3  
nStartPos,nEndPos,i); _j>L4bT  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); h[,XemwX  
fileSplitterFetch.start(); Oc~VHT  
} H\d;QN9Q;  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), kw#X]`c3  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Kk>DYHZ6y  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", sy=dY@W^  
nEndPos = " + nFileLength); U\?+s2I)v  
// fileSplitterFetch[nPos.length-1].start(); )WclV~  
i=V-@|Z  
zg)|rm  
//等待子线程结束 Fq4lXlSB  
//int count = 0; K?JV]^  
//是否结束while循环 UT~4Cfb  
boolean breakWhile = false; `xGT_0&ck  
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while(!bStop) c`pYc  
{ ovSH}h!  
write_nPos(); "G@E6{/  
Utility.sleep(500); Y=|CPE%V  
breakWhile = true; /wlFD,+8  
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for(int i=0;i<nStartPos.length;i++) 5E0wn'  
{ D>S8$]^Dm  
if(!fileSplitterFetch.bDownOver) '?b\F~$8  
{ A`g.[7  
breakWhile = false; m'c#uU  
break; d#4Wj0x  
} L@+Z)# V  
} moe/cO5a9  
if(breakWhile) VH[l\I(h  
break; ys/vI/e\  
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2zM-Ob<U`  
//count++; i
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//if(count>4) l*qk1H"g  
// siteStop(); w~p4S+k&  
} sc9]sIb  
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System.err.println("文件下载结束！"); AT-0}9z{  
} lqauk)(A0  
catch(Exception e){e.printStackTrace ();} =8@RKG`>;  
} qA04Vc[2  
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d0TgqO{  
//获得文件长度 ]M uF
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public long getFileSize() K1<k+t/V  
{ JLml#Pu4  
int nFileLength = -1; u!M&;QL  
try{ "7:u0p!  
URL url = new URL(siteInfoBean.getSSiteURL()); k,AM]H  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); F~%|3a$Y  
httpConnection.setRequestProperty("User-Agent","NetFox"); 8cB=}XgYS  
@::lJDGVv  
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int responseCode=httpConnection.getResponseCode(); J#+Op/mmo  
if(responseCode>=400) *Q0lC1GQ  
{ BL7>dZOa  
processErrorCode(responseCode); 'r6cVBb}  
return -2; //-2 represent access is error xS-w\vbLV  
} b#

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4_WH 6Z  
String sHeader; v [dAywW  
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for(int i=1;;i++) 9OH.&g  
{ `..EQBM  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); z_'dRw  
//Utility.log(in.readLine()); 3Nc'3NPQ'  
sHeader=httpConnection.getHeaderFieldKey(i); e5QOB/e&  
if(sHeader!=null) $x/J+9Ww  
{ 3Sk5I%  
if(sHeader.equals("Content-Length")) EkDws`@  
{ 9GtLMpy  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); makaI0M  
break; U-ERhm>uk  
} kja4!_d  
} 6V+V zDo  
else Sb^add0dT  
break; N!]PIWnC  
} )8 oEs  
} .V7Y2!4TE  
catch(IOException e){e.printStackTrace ();} <1TlW ~q<  
catch(Exception e){e.printStackTrace ();} !,I7 ?O  
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Utility.log(nFileLength); b!0'Qidh0  
}#1UD  

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return nFileLength; K3j_C`Se  
} "4KkKi  
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//保存下载信息（文件指针位置） l# }As.o}  
private void write_nPos() :PHUsy  
{ `^?}s-H+  
try{ )Uc$t${en  
output = new DataOutputStream(new FileOutputStream(tmpFile)); !."Izz/  
output.writeInt(nStartPos.length); ]r"31.w(  
for(int i=0;i<nStartPos.length;i++) h<+PP]l=  
{ qn5yD!1  
// output.writeLong(nPos); @?'t@P:4  
output.writeLong(fileSplitterFetch.nStartPos); >fW+AEt\JB  
output.writeLong(fileSplitterFetch.nEndPos); JHnk%h0  
} #(m`2Z`H  
output.close(); [lmHXf@1C  
} vx({N?  
catch(IOException e){e.printStackTrace ();} d4b 9rtM  
catch(Exception e){e.printStackTrace ();} Pn~pej5'K  
} 8XLxT(YFIs  
nh _DEPMq  
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//读取保存的下载信息（文件指针位置） :!r9 =N9  
private void read_nPos() Bu*W1w\  
{ AGw1Pl8]K  
try{ EGp~Vo-  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); WZfk}To1#  
int nCount = input.readInt(); nXx6L!HJ#  
nStartPos = new long[nCount]; p~,a=  
nEndPos = new long[nCount]; v!WU |=u  
for(int i=0;i<nStartPos.length;i++) QC$=Fs5+  
{ W;xW: -  
nStartPos = input.readLong(); SSl8  
nEndPos = input.readLong(); ]2hF!{wc  
} )$2%&9b  
input.close(); ]#vvlM>/  
} 2+c>O%L  
catch(IOException e){e.printStackTrace ();} M Ak-=?t  
catch(Exception e){e.printStackTrace ();} /vFxVBX  
} {hkM*:U  
s!8J.hD'I  
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private void processErrorCode(int nErrorCode) Co
{MIuL  
{ pko!{,c  
System.err.println("Error Code : " + nErrorCode); ,mAB)at  
} )R [@G.  
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xiOv$.@q  
//停止文件下载 |G`4"``]k  
public void siteStop() *7:u-}c!  
{ gJ)h9e*m^  
bStop = true; 'sT}DX(7M  
for(int i=0;i<nStartPos.length;i++) $@+p~)r(l  
fileSplitterFetch.splitterStop(); >Hd~Ca>  
0 .6X{kO  

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} 3B!&ow<rt  
} N}.Q%&6:  
//负责部分文件的抓取 sRo<4U0M;l  
**FileSplitterFetch.java C,sD?PcSi+  
*/ 2n-Tpay0  
package NetFox; bc0)'a\  
!`O_VV`/@  
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import java.io.*; (hRgYwUa<  
import java.net.*; >#"jfjDuR
 
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public class FileSplitterFetch extends Thread { Mipm&5R  
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String sURL; //File URL $ ufSNx(F  
long nStartPos; //File Snippet Start Position 9H !B)  
long nEndPos; //File Snippet End Position Q KcF1?  
int nThreadID; //Thread's ID d[P>jl%7  
boolean bDownOver = false; //Downing is over e4>L@7  
boolean bStop = false; //Stop identical IGF37';;  
FileAccessI fileAccessI = null; //File Access interface vV:MS O'r  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException >[E|p6jgT  
{ ei|*s+OZu  
this.sURL = sURL; 8;+Hou  
this.nStartPos = nStart; kMJQeo79  
this.nEndPos = nEnd; fY,@2VxyfA  
nThreadID = id; OI]K_ m3  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 LS2ek*FJO  
} 61s2bt#  
ZH`K%h0  
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public void run() rlUdAa3  
{ K[Egwk7  
while(nStartPos < nEndPos && !bStop) <x>k
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{ 5m%baf2_  
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try{ u75)>^:I   
URL url = new URL(sURL); <L!~f`nH2  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); pd
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httpConnection.setRequestProperty("User-Agent","NetFox"); CL<KBmW7  
String sProperty = "bytes="+nStartPos+"-"; ,XBV}y  
httpConnection.setRequestProperty("RANGE",sProperty); Dbkuh!R  
Utility.log(sProperty); sBuq  
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K,L>
  
InputStream input = httpConnection.getInputStream(); ]\os`At  
//logResponseHead(httpConnection); QU,TAO  
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t7*H8  
byte[] b = new byte[1024]; Hq"<
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int nRead; KHc/x8^9  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) "[".3V  
{ Cr V2 V)|G  
nStartPos += fileAccessI.write(b,0,nRead); ~\@<8@N2a6  
//if(nThreadID == 1) :}3qZX  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ^*?B)D=,  
} wE8a4.  
/F8\%l+  
3<UDVt@0  
Utility.log("Thread " + nThreadID + " is over!"); \$~oH3m&  
bDownOver = true; D?*sdm9r`  
//nPos = fileAccessI.write (b,0,nRead); wTMHoU*>  
} G|6|;  
catch(Exception e){e.printStackTrace ();} eB/hyC1  
} W_f"Gk  
} "6*Kgf2G  
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"ZJ1`R=Mj  
//打印回应的头信息 J:mu%N`  
public void logResponseHead(HttpURLConnection con) (fk, 80  
{ 1VyO?KX'  
for(int i=1;;i++) G4iLCcjY  
{ n%MYX'0  
String header=con.getHeaderFieldKey(i); !EmR(x  
if(header!=null) EB
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//responseHeaders.put(header,httpConnection.getHeaderField(header)); ]RrP !|^  
Utility.log(header+" : "+con.getHeaderField(header)); _G}CD|Kx  
else }r<@o3t  
break; \Q?|gfJH  
} M\.T 0M_  
} [nPzhXs  
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public void splitterStop() =Q=&Ucf_  
{ fFTvf0j  
bStop = true; B,m$ur#$  
} GZhfA ;O,  
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} TLL[F;uZ  
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/* E_gDwWot  
**FileAccess.java LN3dp?;_{  
*//文件访问(定位，写) divZJc  
package NetFox; ]x(2}h^
S  
import java.io.*; z:Zn.e*$b  
*/Ry6Yu  
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public class FileAccessI implements Serializable{ hC 4X Y  
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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 8|-mzb&  
RandomAccessFile oSavedFile; fe9& V2Uu  
long nPos; Qpv}N*v^  

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public FileAccessI() throws IOException =*>4Gh i  
{ &F*QYz[  
this("",0); 1PTu3o&3  
} ~ GT\RAj[  
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public FileAccessI(String sName,long nPos) throws IOException d @kLLDP  
{ $E_vCB_  
oSavedFile = new RandomAccessFile(sName,"rw"); g(Xg%&@KZ  
this.nPos = nPos; r5qx! >  
oSavedFile.seek(nPos); IOSoc 7+"  
} ]pP2c[;  
16> >4U:Y  
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public synchronized int write(byte[] b,int nStart,int nLen) d|?(c~  
{ >8
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int n = -1; L9YwOSb.  
try{ k| cI!   
oSavedFile.write(b,nStart,nLen); .5CELtR  
n = nLen; #M9D" <pn}  
} #m$%S%s  
catch(IOException e) K,,@',  
{ ,JBw$C  
e.printStackTrace (); [dF=1E>W_J  
} w{O3P"N2  
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return n; *u4X<oBS*  
} #|_UA}Y  
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} 68GGS`&  
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/* Y&!]I84]  
**SiteInfoBean.java 898wZ{9  
*/ Z *
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package NetFox; aC }1]7  
m#K

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public class SiteInfoBean { b`|MK4M(  
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private String sSiteURL; //Site's URL hYv 6-5_  
private String sFilePath; //Saved File's Path <J}9.k
 
private String sFileName; //Saved File's Name |QTqa~~B  
private int nSplitter; //Count of Splited Downloading File iEgM~  
-+_
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public SiteInfoBean()
4
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{//nSplitter的缺省值为5 Yg,lJ!q  
//default value of nSplitter is 5 n@,eZ!  
this("","","",5); p{svXP K  
} W#_gvW  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) P:-/3  
{ WJ8vHPSM  
sSiteURL= sURL; 7`<? fO  
sFilePath = sPath; X6*y/KGN  
sFileName = sName; &r5%WRzpYT  
this.nSplitter = nSpiltter; +siNU#!  
8Y~T$Yj^  
>upUY(3&  
} RkP|_Bf8)  
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public String getSSiteURL() 2|>wY%  
{ yx;R#8;b.  
return sSiteURL; UkbQ'P+oS  
} R/cq00g
 
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public void setSSiteURL(String value) JU \J   
{ |=}~>!!  
sSiteURL = value; m:O2_%\l  
} -t'oW*kdL  
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public String getSFilePath() !enz05VW6.  
{ ]%8;c  
return sFilePath; :p)9Heu  
} Wc;D{p?Lb  
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public void setSFilePath(String value) Y'*h_K  
{ (wF$"c3'{  
sFilePath = value; U9sub6w6  
} 7{
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7#.PMyK9  
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public String getSFileName()  !Ocg  
{ tU/NwA"  
return sFileName; %_
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} <G?85*Nv_  
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public void setSFileName(String value) < ^!eaBR4  
{ !r
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sFileName = value; ?'m5)Z{  
} x)Kh_G  
@_ZW
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public int getNSplitter() 9],"AjD  
{ 8&hn$~ate  
return nSplitter; 0 3 $ W  
} s(Bi&C\  
l<_mag/j9o  
.h^Ld,Chj  
public void setNSplitter(int nCount) H4A+Dg,  
{ usf(U>  
nSplitter = nCount; g7f%(W2dd  
} 5{aQ4H>~tx  
} ,?~,"IQyi[  
ui0(#2'h%  
&sc
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/* 2dW-WHaM  
**Utility.java g]JI}O*5  
*/ <{Wa[1D  
package NetFox; $:Zxb  
*X5LyO3-gP  
Q 5TyS8  
public class Utility { 0Hf-~6  
S^=/}PT'  
}gaKO 5  
public Utility() w*@Z-'(j  
{ PMZzzZ  
,1h(k<-  
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} P"<ad kr  
vtjG&0GSK  
//线程睡眠 >g=:01z9  
public static void sleep(int nSecond) aKcV39brr  
{ HXo'^^}q;  
try{ sM[c\Z]  
Thread.sleep(nSecond); ]^%3Y  
} 1h{_v!X  
catch(Exception e) v>l?d27R  
{ ^S$w,  
e.printStackTrace (); 5OE?;PJ(  
} ?q`mr_x%?  
} wO NQlt  
l]cQ7
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//日志 { )K(}~VD  
public static void log(String sMsg) Q"uu&JC  
{ aW5
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System.err.println(sMsg); i?9Lf  
} xSZw,  
tF(mD=[  
yB[LO(i  
public static void log(int sMsg) a)b@en;v  
{ VQ`O;n6/`  
System.err.println(sMsg); _~"3 LB  
} ?Kf@/jv  
} aS2 Y6  
_: x$"i  
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/* ),|bP`V  
**TestMethod.java H8U*oLlc  
*/ x$sQ .aT  
package NetFox; w"J(sVy4  
~coG8r"o  
S?$T=[yY)  
public class TestMethod { )I_I?e  
;rbn/6  
@,.H)\a4  
public TestMethod() dno*Usx5d0  
{ ///xx/weblogic60b2_win.exe ,B><la87  
try{ Ho|n\7$  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); D1 z3E;:  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); fRmc_tx  
SiteFileFetch fileFetch = new SiteFileFetch(bean); K`3cH6"L6  
fileFetch.start(); *z~Y*Q0  
} :=@[FXD4  
catch(Exception e){e.printStackTrace ();} >[U$n.  
 t&]IgF  
G#>X~qk()  
} ;?9~^,l  
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public static void main(String[] args) n\4+xZr  
{ -TWo-iu^  
new TestMethod(); .>e~J+oL  
} @P>@;S  
} C+j+q648>  
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