http断点续传简单实现（java)

/* _*ar\A`  
**SiteFileFetch.java VS3lz?o?6g  
*/ gg/2R?O]  
package NetFox; rvuasr~  
import java.io.*; =q}Z2 OoYh  
import java.net.*; Rj3ad3z'E  
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public class SiteFileFetch extends Thread { _rg*K  
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SiteInfoBean siteInfoBean = null; //文件信息Bean N}nE?|N=5  
long[] nStartPos; //开始位置 o)n=n!A  
long[] nEndPos; //结束位置 7{\6EC}d[&  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ~r_2V$sC2  
long nFileLength; //文件长度 $WXO1o(O  
boolean bFirst = true; //是否第一次取文件 8[;AFm?,`  
boolean bStop = false; //停止标志 2!R+5^Iy  
File tmpFile; //文件下载的临时信息 PD~vq^@Q  
DataOutputStream output; //输出到文件的输出流 s|I$c;>  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 6^lix9q7  
public SiteFileFetch(SiteInfoBean bean) throws IOException 0?cJ>)N  
{ ~OWpk)Vq  
siteInfoBean = bean; (8~D^N6Z  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); a"l\_D'.K8  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); UF$O@l  
if(tmpFile.exists ()) "7eL&  
{ g7{:F\S  
bFirst = false; dQ_h
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read_nPos(); C3'?E<F  
} izzX$O[=:  
else Tgl>  
{
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nStartPos = new long[bean.getNSplitter()]; V|~o`(]  
nEndPos = new long[bean.getNSplitter()]; U>sEFzBup  
} e
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} V"B/4v>  
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public void run() xIwILY|W=  
{ O`5hjq#  
//获得文件长度 +cM~|  
//分割文件 h^ K]ASj  
//实例FileSplitterFetch =WHI/|&  
//启动FileSplitterFetch线程 f[ KI T  
//等待子线程返回 o/ 7[ G  
try{ 6AoKuT;
 
if(bFirst) IJVzF1vC  
{ {u+=K-Bj  
nFileLength = getFileSize(); [.}Uzx  
if(nFileLength == -1) xz,o Mlw  
{ "dT"6,  
System.err.println("File Length is not known!"); 10)RLh|+  
} $f%om)  
else if(nFileLength == -2) 'rTJ*1i  
{ z{&z  
System.err.println("File is not access!"); qzEv!?)a  
} 56
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else YrYmPSb=  
{ 7dv!  
for(int i=0;i<nStartPos.length;i++) ;+.cD
 
{ c3 )jsf  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); yZN~
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} o/Q|R+yXV  
for(int i=0;i<nEndPos.length-1;i++) i]OEhB Y  
{ $E.Fgy:G  
nEndPos = nStartPos[i+1]; ANgt\8  
} P)#h4|xZ  
nEndPos[nEndPos.length-1] = nFileLength; ?^2nrh,n+  
} q!W=U8`  
} Y`(~eNX^%  
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//启动子线程 wa~zb!y<  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; /]U;7)  
for(int i=0;i<nStartPos.length;i++) (G/(w%#7_  
{ &H P g>  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), |sY  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), )0DgFA6k_  
nStartPos,nEndPos,i); E-($Xc  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); T "hjL  
fileSplitterFetch.start(); wph8ln"C-  
} s;..a&C'  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), B"zB=Aw  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Xk/iyp/  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ~y?Nn8+&f  
nEndPos = " + nFileLength); #oR`_Dm)P  
// fileSplitterFetch[nPos.length-1].start(); \
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//等待子线程结束 a 9{:ot8,  
//int count = 0; _aBy>=2c$  
//是否结束while循环 u!&T}i:  
boolean breakWhile = false; RRpY%-8M  
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while(!bStop) IC(:RtJ  
{ D.Cn`O}  
write_nPos(); jm@,Ihz=wI  
Utility.sleep(500); *8uS,s6g  
breakWhile = true; ecQ{ePoU  
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for(int i=0;i<nStartPos.length;i++) P3n#s2o6y  
{ "}#%h&,  
if(!fileSplitterFetch.bDownOver) \*'@F+  
{ TLp2a<Iy  
breakWhile = false; a
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break; O!^ >YvOh  
} J3~%9MCJ  
} ?{jey_]M  
if(breakWhile) *^Ges;5$"  
break; H(tC4'tA  
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//count++; idGn{f((f  
//if(count>4) s^SU6P/]  
// siteStop(); "(vK.-T  
} Z^z{, u;!  
2~l7WW+lx,  
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System.err.println("文件下载结束！"); rsLkH&aM  
} PH%'^YAl7  
catch(Exception e){e.printStackTrace ();} #ACT&J  
} sW'_K.z  
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//获得文件长度 GlTpK^
.  
public long getFileSize() (QL:7  
{ S9]I[4  
int nFileLength = -1; 'S9o!hb'@  
try{ f6yj\qq]  
URL url = new URL(siteInfoBean.getSSiteURL()); cm_5,wB(w  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); c61OT@dZEA  
httpConnection.setRequestProperty("User-Agent","NetFox"); `/`iLso&-  
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int responseCode=httpConnection.getResponseCode(); %OB>FY:|  
if(responseCode>=400) IW&*3I<K  
{ +Ugy=678Tr  
processErrorCode(responseCode); > Xh=P%  
return -2; //-2 represent access is error jex\5  
} !=
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String sHeader; 2oV6#!{Z  
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for(int i=1;;i++) 4v |i\V>M  
{ +])
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//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); A&p@iE*/  
//Utility.log(in.readLine()); U5TkgHN{y  
sHeader=httpConnection.getHeaderFieldKey(i); tpEy-"D&  
if(sHeader!=null) wpt$bqs|1  
{ 7)5G 1  
if(sHeader.equals("Content-Length")) _h5d~  
{ S{N4[U?V>  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 2T)k-3  
break; C?>d$G8  
} FeMgn`q  
} cu foP&  
else Knqv|jJVx1  
break; JVkuSIR>  
} m$^5{qpg  
} q~ ZUtF  
catch(IOException e){e.printStackTrace ();} A{J?I:  
catch(Exception e){e.printStackTrace ();} ?d%{-  
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Utility.log(nFileLength); |h6!bt!=  
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return nFileLength; 4'*-[TKC  
} 0)g]pG8&ro  
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//保存下载信息（文件指针位置） ?A7 AVR
 
private void write_nPos() X/cb1#  
{ BJb,  
try{ !reOYt|  
output = new DataOutputStream(new FileOutputStream(tmpFile)); =pi,]m  
output.writeInt(nStartPos.length); NfPWcK[  
for(int i=0;i<nStartPos.length;i++) iKV|~7
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{ YVa,?&i=N  
// output.writeLong(nPos); Zv!XNc!"$y  
output.writeLong(fileSplitterFetch.nStartPos); ;`LG WT-<F  
output.writeLong(fileSplitterFetch.nEndPos); ,$/Ld76U  
} 5I1YB+$}e  
output.close(); +aL
 
} FXDB> }8  
catch(IOException e){e.printStackTrace ();} hZ452W  
catch(Exception e){e.printStackTrace ();} Y:O|6%00Y  
} %a WRXW@c  
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#}B1W&\sw  
//读取保存的下载信息（文件指针位置） J.XhP_aT  
private void read_nPos() Um\HX6  
{ MnqT?Cc4$j  
try{ }Vob)r{R@  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); w^ z ftm  
int nCount = input.readInt(); :%J;[bS+  
nStartPos = new long[nCount]; i6k6l%  
nEndPos = new long[nCount]; 0C%IdV%CU  
for(int i=0;i<nStartPos.length;i++) lSaX!${R'T  
{ yc?L OW0  
nStartPos = input.readLong(); RHn3\N  
nEndPos = input.readLong(); *(1<J2j  
} G.<0^q,  
input.close(); LYL_Ah'=  
} M>m!\bb%.  
catch(IOException e){e.printStackTrace ();} @@K/0:],  
catch(Exception e){e.printStackTrace ();}
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} '_
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private void processErrorCode(int nErrorCode) 9uWg4U  
{ hvO$ f.i  
System.err.println("Error Code : " + nErrorCode); ]58~b%s  
} $Z]@N nA9N  
!`H{jwH  
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//停止文件下载 R|(X_A  
public void siteStop() I50LysM  
{ +em!TO  
bStop = true; 68h1Wjg:"!  
for(int i=0;i<nStartPos.length;i++) Mz(?_7  
fileSplitterFetch.splitterStop(); S-o
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} _[z)%`kay  
} ~K#
92  
//负责部分文件的抓取 R,78}7B  
**FileSplitterFetch.java 8CRbo24"s  
*/ h7fytO  
package NetFox; beikzuC  
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,~38IIS>_  
import java.io.*; PVF:p7  
import java.net.*; B*O/>=_  
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public class FileSplitterFetch extends Thread { CKZEX*mPC  
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String sURL; //File URL V\L%*6O  
long nStartPos; //File Snippet Start Position 2f%+1uU  
long nEndPos; //File Snippet End Position q'y<UyT6  
int nThreadID; //Thread's ID 6 F39'  
boolean bDownOver = false; //Downing is over <w*WL_P  
boolean bStop = false; //Stop identical 'J0I$-QYk  
FileAccessI fileAccessI = null; //File Access interface 0/|Ax-dK  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException wBw(T1VN  
{ m*B4a9f  
this.sURL = sURL; Z*b l J5YC  
this.nStartPos = nStart; ~@Bw(!  
this.nEndPos = nEnd; t OJyj49^a  
nThreadID = id; =vF!  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 hg<[@Q%$o  
} /%jX=S.5h<  
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public void run() -e0[$v  
{ 6!itr"  
while(nStartPos < nEndPos && !bStop) :EYUBtTj  
{ `s+kYWg'Z  
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try{ /+`%u&<  
URL url = new URL(sURL); ^ZS!1%1  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); NySa%7@CD  
httpConnection.setRequestProperty("User-Agent","NetFox"); !"RRw&0M  
String sProperty = "bytes="+nStartPos+"-"; YuIF}mUr"  
httpConnection.setRequestProperty("RANGE",sProperty); .I#_~
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Utility.log(sProperty); >/ A'G  
{' 0#<Z  
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InputStream input = httpConnection.getInputStream(); 4e|N^h*!  
//logResponseHead(httpConnection); A*/8j\{n  
2,g4yXws5  
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byte[] b = new byte[1024]; o-l-Z|)7  
int nRead; k#\j\t-  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) eGpKoq7a  
{ Y}2Sr-@u  
nStartPos += fileAccessI.write(b,0,nRead); HIE8@Rv/3  
//if(nThreadID == 1) d8 Jf3Mo  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 7hPwa3D^  
} ~G=E Q]a
  
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Utility.log("Thread " + nThreadID + " is over!"); C'gv#!Q  
bDownOver = true; +|X`cmnuU  
//nPos = fileAccessI.write (b,0,nRead); q`L)^In"  
} o^"OKHU,S0  
catch(Exception e){e.printStackTrace ();} 
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} ='qVwM['  
} 5cU:wc  
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< Mu`,Kv*  
//打印回应的头信息 gdqBT]j  
public void logResponseHead(HttpURLConnection con) kFmtE dhsc  
{ LA2/<:  
for(int i=1;;i++) P,-5af*;  
{ BV7P_!vt  
String header=con.getHeaderFieldKey(i); LdNpb;*  
if(header!=null) p-EU"O  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); YtWw)IK  
Utility.log(header+" : "+con.getHeaderField(header)); a:HN#P)12  
else ;]>)6  
break; MVvBd3  
} f`/('}t  
} @0t[7Nv-1  
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public void splitterStop() _TsN%)m  
{ p19@t
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bStop = true; f>ktv76  
} E7@Gpu,o  
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} ~re}6-?  
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/* Xa?igbgAwx  
**FileAccess.java ;i?2^xe^~c  
*//文件访问(定位，写) 'OP0#`6`  
package NetFox; ]Z6? m  
import java.io.*; wik<#ke  
+YW;63"
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public class FileAccessI implements Serializable{ BU??}{  
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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 "qR, V9\  
RandomAccessFile oSavedFile; \ ya@9OA  
long nPos; 2YW;=n  
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public FileAccessI() throws IOException =QtFJ9\  
{ Jx}-Y* o  
this("",0); p!uB8F  
} y'4Qt.1ukN  
?(d1;/0v>  
Fc\]*  
public FileAccessI(String sName,long nPos) throws IOException 7/QK"0  
{ we^'R}d  
oSavedFile = new RandomAccessFile(sName,"rw"); W9tZX5V1  
this.nPos = nPos; { ,c*OR  
oSavedFile.seek(nPos); h ka_Fo  
} ZM v\j|{8  
Rb:<?&7ZzN  
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public synchronized int write(byte[] b,int nStart,int nLen) u4SL:IH{D  
{ C]5 kQ1Og  
int n = -1; bl^Ihza  
try{ |M5#jVXj  
oSavedFile.write(b,nStart,nLen); \DZ.#=d  
n = nLen; ~).D\Q\  
} N\|z{vn  
catch(IOException e) QNU~G3  
{ z_ycH%p  
e.printStackTrace (); b-  t  
} s[0`  
b=:ud[h  
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return n; (iir,Ks2C  
} ([<HFc`  
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} ;;+AdN5  
.aY$-Y<  
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/* |JYb4J4Ni  
**SiteInfoBean.java Kh$"5dy  
*/ IV. })8
 
package NetFox; ySO\9#Ho  
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public class SiteInfoBean { <YFDS;b|  
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private String sSiteURL; //Site's URL \M\7k5$  
private String sFilePath; //Saved File's Path %C
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private String sFileName; //Saved File's Name $-1ajSVJ  
private int nSplitter; //Count of Splited Downloading File 5>f"
  
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public SiteInfoBean() zs#-E_^%M  
{//nSplitter的缺省值为5 !9/`PcNIpy  
//default value of nSplitter is 5 'A:Y&w"r  
this("","","",5); u)r/#fUZ  
} a&8K5Z%0  
nahq O|~  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) \]Ah=`  
{ !s=$UC  
sSiteURL= sURL; `X@\Zv=}  
sFilePath = sPath; "73y}'  
sFileName = sName; bOr11?
 
this.nSplitter = nSpiltter; ?(=|!`IoO  
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} J2VPOn  
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public String getSSiteURL() [y`Gp#  
{ q
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return sSiteURL; *P*~CHx
>  
} ?l6yLn5si^  
,Lp"Ia  
vm+3!s:u  
public void setSSiteURL(String value) Bn&P@C$7  
{ z]8Mv(eL  
sSiteURL = value; Q*#Lr4cm{  
} fKY-@B[|  
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vf3)T;X>  
public String getSFilePath() Jl\xE`-7  
{ S,:!H@~B  
return sFilePath; i`F5  
} 9y6u&!PZ\  
cOP'ql{"  
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public void setSFilePath(String value) QHO n?e  
{ /W,hO
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sFilePath = value; fU$Jh/#":  
} SzpUCr"  
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public String getSFileName() 1r>]XhRFZ  
{ UiV#w#&P  
return sFileName; j%'2^C8  
} )Q`Ycz-  
3#,6(k4>  
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public void setSFileName(String value) H1U$ApD  
{ [&99#7B  
sFileName = value;
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} HQ"T>xb  
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public int getNSplitter() M4)U [v  
{ H3$py|}lL  
return nSplitter; ^)]U5+g?  
} vE(]!CB  
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26aDPTP$<  
public void setNSplitter(int nCount) X9?)P5h=  
{ %( 7##f_  
nSplitter = nCount; <MJU:m$3  
} Rnwm6nu  
} ShC$ue?Q  
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-'qVnu  
/* 9+9g(6
 
**Utility.java rAP="H<  
*/ \}h  
package NetFox; F&!vtlV)  
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public class Utility { =_BHpgL  
9Zd\6F,  
X[Ufq^fyA  
public Utility() NUVKAAgMX  
{ g|uyQhsg  
j=T8b  
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} W2rd[W  
Az y`
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//线程睡眠 Q(-&}cY  
public static void sleep(int nSecond) {E%c%zzQ  
{ o}QP+  
try{ t[+bZUS$~  
Thread.sleep(nSecond); rP]|`*B  
} rkji#\_-FV  
catch(Exception e) T1$p%yQH  
{ OF`J{`{r  
e.printStackTrace (); 34Gu @"  
} v\dQjQu8m  
} fx+_;y  
octQ[QXo#  
//日志 W7A!QS  
public static void log(String sMsg) Pa0W|q#?X  
{ tf7HhOCYX  
System.err.println(sMsg); ,Tar?&C:  
} &,<,!j)Jr  
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public static void log(int sMsg) ZqrS]i@$  
{ _+9i  
System.err.println(sMsg); ^_3Ey  
} r
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} `},:dDHI  
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/* Q e+;BE-H  
**TestMethod.java jj2=|)w$3  
*/ +o4o!;E)  
package NetFox; l(rm0_  
K
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;6R9k]5P%  
public class TestMethod { > "rM\ Q  
e eN`T&cI  
~l:Cj*6x8  
public TestMethod() 1Q FsT  
{ ///xx/weblogic60b2_win.exe X=-=z5  
try{ yLLA:5Q1  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ]\K?%z
  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); &TRKd)wd  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Trh t2Iv  
fileFetch.start(); l-W)?d  
} gYN;Fu-9Z  
catch(Exception e){e.printStackTrace ();} zUJXA:L9  
gzi=+oJ|4  
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} 0^Ldw)C"  
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public static void main(String[] args) h(nE
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{ %P1zb7:8  
new TestMethod(); z^gz kXx7  
} _:Q^mV=;j  
} l+6@,TY1U  
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