http断点续传简单实现（java)

/* e/6WhFN#  
**SiteFileFetch.java 8ysU.5S  
*/ N~;=*)_VH  
package NetFox; oA(jtX[(  
import java.io.*; Gk;==~  
import java.net.*; 1U;je,)  
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public class SiteFileFetch extends Thread { y5kqnibh@  
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SiteInfoBean siteInfoBean = null; //文件信息Bean |+~CdA  
long[] nStartPos; //开始位置 Pg{Dy>&2`I  
long[] nEndPos; //结束位置 pZ/x,b#.  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 7 }4T)k(a  
long nFileLength; //文件长度 C;0H _  
boolean bFirst = true; //是否第一次取文件 YjdCCju  
boolean bStop = false; //停止标志 b
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File tmpFile; //文件下载的临时信息 RgHPYf{  
DataOutputStream output; //输出到文件的输出流 9.m_3"s  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） _"&b%!  
public SiteFileFetch(SiteInfoBean bean) throws IOException |P$tLOrG  
{ S)iv k x  
siteInfoBean = bean; o|>2X[T  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); &$lz@Z  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ^o,P>u!9  
if(tmpFile.exists ()) @.yp IE\  
{ DxdiXf[j  
bFirst = false; Wrf(
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read_nPos(); :XxsDD  
} S;kI\;  
else #~^#%G
 
{ yd$_XWp?\  
nStartPos = new long[bean.getNSplitter()]; \EuMzb"G9p  
nEndPos = new long[bean.getNSplitter()]; hk3}}jc  
} 1\z5[ _  
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} 5D8V)i  
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public void run() mHrt)0\_  
{ sMlY!3{Ix  
//获得文件长度 +)k%jIi!  
//分割文件 0-M.>fwZ=  
//实例FileSplitterFetch %JeT,{  
//启动FileSplitterFetch线程 "_WOtJr  
//等待子线程返回 rz+)z:u  
try{ ~~!iDF\  
if(bFirst) b
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{ HJ?p,V q5_  
nFileLength = getFileSize(); 8fRk8  
if(nFileLength == -1) I(y:Td  
{ X:+lD58  
System.err.println("File Length is not known!"); FpN>T  
} N9
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else if(nFileLength == -2) |re)]%A?Fu  
{ f40xS7-Q0  
System.err.println("File is not access!"); i%w[v_j  
} j;6kN-jx  
else ]awu7}C9Z  
{ 
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for(int i=0;i<nStartPos.length;i++) Mhp6,JL  
{ ,7-@eZ  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); wXI6KN-  
} ^h #0e:7<  
for(int i=0;i<nEndPos.length-1;i++) DdDwMq  
{ }GI8p* ]o=  
nEndPos = nStartPos[i+1]; t)o!OEnE  
} t M?3oO  
nEndPos[nEndPos.length-1] = nFileLength; :j f
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} uU_lC5A|  
} ;%wQ
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zr#n^?m  
6?\X)qBI  
//启动子线程 |:)UNb?R"O  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; <4UF/G)  
for(int i=0;i<nStartPos.length;i++) |uL"/cMW7  
{ )vWI{Q]r  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), DvL/xlN  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), bDK%vx!_  
nStartPos,nEndPos,i); f4{O~?=  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); a2Q_K2t  
fileSplitterFetch.start(); l@C3
9VP  
} X'[93 C|K  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ]1YyP  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); @px4[  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Igb@aGA  
nEndPos = " + nFileLength); wP-BaB$_  
// fileSplitterFetch[nPos.length-1].start(); +7%}SV 2)  
hf#[Vns  
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//等待子线程结束 W[ZW=c  
//int count = 0; lJ y\Ky(*  
//是否结束while循环 yex4A)n9"'  
boolean breakWhile = false; zNg8Oq&  
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while(!bStop) m~$S]Wf  
{ 3/d`s0O  
write_nPos(); (>.+tq}  
Utility.sleep(500); y*6-
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breakWhile = true; h4N%(?7  
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for(int i=0;i<nStartPos.length;i++) O C qI  
{ 9pY`_lxa>  
if(!fileSplitterFetch.bDownOver) {Kdr-aC  
{ H6fR6Kr4j  
breakWhile = false; )cF1?2  
break; cwK+{*ZH/
 
} L~Hgf/%5  
} 4=b{k,kzgA  
if(breakWhile) Td|x~mZv:  
break; aC
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//count++; Hf^Tok^6@]  
//if(count>4) VlLc[eVV  
// siteStop(); \Gzo^w  
} VOmWRy"L  
,:G3Y )  
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System.err.println("文件下载结束！"); IQ9jTkW l  
} #!h +K"wX  
catch(Exception e){e.printStackTrace ();} pbM"tr_A{  
} bM%c*_$F7  
r]0UF0#  
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//获得文件长度 *`(/wE2v]  
public long getFileSize() !edgziuO  
{ m4@f&6x  
int nFileLength = -1; #h#Bcv0 Z  
try{ $ZQ?E^> B  
URL url = new URL(siteInfoBean.getSSiteURL()); SdI/  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); lQ}e"#<  
httpConnection.setRequestProperty("User-Agent","NetFox"); rX8EXraO  
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int responseCode=httpConnection.getResponseCode(); CCX!>k]  
if(responseCode>=400) l5jW`cl1  
{ D(GAC!|/]  
processErrorCode(responseCode); 0M?nXHA[  
return -2; //-2 represent access is error tv
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} HxVQeyOR  
GW(-'V/  
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String sHeader; ~'4:{xH  
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zn |=Q$81  
for(int i=1;;i++) z"eh.&T  
{ h=3156M  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); lRn6Zh  
//Utility.log(in.readLine()); bW`@9 =E  
sHeader=httpConnection.getHeaderFieldKey(i); #0-!P+c[  
if(sHeader!=null) %5_eos&<^)  
{ V.Ig
EE]  
if(sHeader.equals("Content-Length")) cZRLYOC  
{ Z?%j5G=4w  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ]`D(/l'  
break; 5k`[a93T  
} "9[K  
} S?{|qlpy  
else VA _O0y2  
break; Ru?Ue4W^b  
} pGi "*oZD  
} u.gh04{5  
catch(IOException e){e.printStackTrace ();} NgKbf vt  
catch(Exception e){e.printStackTrace ();} EX>|+zYL  
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Utility.log(nFileLength); h^P>pI~  
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return nFileLength; #R|M(Z">q  
} W%09.bF  
Z'GOp?  
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//保存下载信息（文件指针位置） +G&h  
private void write_nPos() Y*``C):K%  
{ $JTy`g0>x  
try{ =JyYU*G4  
output = new DataOutputStream(new FileOutputStream(tmpFile)); J+&AtGq]u  
output.writeInt(nStartPos.length); 1vu4}%nD  
for(int i=0;i<nStartPos.length;i++) )J_!ZpMC  
{ Q8M&nf  
// output.writeLong(nPos); r2.87   
output.writeLong(fileSplitterFetch.nStartPos); &a8#qv"l  
output.writeLong(fileSplitterFetch.nEndPos); ^h^2='p  
} n?pCMS|  
output.close(); .jr1<LE  
} ;,'!  
catch(IOException e){e.printStackTrace ();} UhY )rezh  
catch(Exception e){e.printStackTrace ();} N|Ua|^  
} i#1T68y}  
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//读取保存的下载信息（文件指针位置） |.:O$/ Tt[  
private void read_nPos() %@Ks<"9  
{ ,-c(D-&  
try{ S:vv*5  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); *@G4i  
int nCount = input.readInt(); ;lX:EU  
nStartPos = new long[nCount]; Ph]e\  
nEndPos = new long[nCount]; |gxU;"2`5~  
for(int i=0;i<nStartPos.length;i++) FTCp3g  
{ GQ|kcY=  
nStartPos = input.readLong(); B0q![  
nEndPos = input.readLong(); Eg-b5Z);  
} 2I?HBz1v  
input.close(); =]xNpX)  
} M=o,Sav5*  
catch(IOException e){e.printStackTrace ();} UXQ{J5Ox+  
catch(Exception e){e.printStackTrace ();} h#]}J}si  
} OM!ES%c,  
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private void processErrorCode(int nErrorCode) >w j7Y`  
{ 4N$svA  
System.err.println("Error Code : " + nErrorCode); mu"]B]
 
} XN=<s;U
 
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//停止文件下载 0M8JE9 Kx  
public void siteStop() [po+a@ %  
{ & p_;&P_  
bStop = true; 5)$U<^uy  
for(int i=0;i<nStartPos.length;i++) Go`omh b  
fileSplitterFetch.splitterStop(); 'hya#rC&(  
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} ['s_qCA[  
} m]"YR_  
//负责部分文件的抓取 ['R=@.  
**FileSplitterFetch.java !%s7I^f*  
*/ 3gabk/  
package NetFox; .k*2T<p$rC  
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import java.io.*; iT5H<uS  
import java.net.*; b%PVF&C9W  
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public class FileSplitterFetch extends Thread { jQ^Ib]"K  
qyJpm{  
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String sURL; //File URL =oh6;Ojt  
long nStartPos; //File Snippet Start Position I^ >zr.zA  
long nEndPos; //File Snippet End Position "mH^Owai  
int nThreadID; //Thread's ID .86..1  
boolean bDownOver = false; //Downing is over 3\WES!  
boolean bStop = false; //Stop identical ffB]4  
FileAccessI fileAccessI = null; //File Access interface a<o0B{7{BM  
/N^+a-.Qd  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException A!Yqj~  
{ CTP
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this.sURL = sURL; n=>Gu9`  
this.nStartPos = nStart; C {,d4KG  
this.nEndPos = nEnd; >L;O, {Px-  
nThreadID = id; 3AL.UBj&}  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 "Jwz.,Y\  
} /<2_K4(-{4  
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public void run() a,E;R$[!  
{ n$?oZ*;  
while(nStartPos < nEndPos && !bStop) bc"N  
{ a;zcAeX  
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try{ jl@8pO$  
URL url = new URL(sURL); W!(Q_B  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 

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httpConnection.setRequestProperty("User-Agent","NetFox"); K%k,-  
String sProperty = "bytes="+nStartPos+"-"; Zk[#BUA  
httpConnection.setRequestProperty("RANGE",sProperty); **"P A8  
Utility.log(sProperty); :Rn9rdX  
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InputStream input = httpConnection.getInputStream(); PA/6l"-`3  
//logResponseHead(httpConnection); O(d'8`8  
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byte[] b = new byte[1024]; 6\K)\  
int nRead; a
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while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ivq4/Y]-X  
{ g;h&Xkp  
nStartPos += fileAccessI.write(b,0,nRead); rij[ZrJ  
//if(nThreadID == 1) ^PI49iB  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); _6' g]4  
} 3C2>  
{;zPW!G  
\);rOqh  
Utility.log("Thread " + nThreadID + " is over!"); ZS+2.)A  
bDownOver = true; -{h[W bf  
//nPos = fileAccessI.write (b,0,nRead); M@\'Y$)Y{  
} hA8 zXk/'8  
catch(Exception e){e.printStackTrace ();} nM`)`!/  
} f+
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} >`:+d'Jv0  
/HRaX!|E#  
$#r(1 Ev  
//打印回应的头信息 "x)DE,  
public void logResponseHead(HttpURLConnection con) ]YP?bP,:  
{ K5SO($  
for(int i=1;;i++) m"R(_E5  
{ f#5JAR  
String header=con.getHeaderFieldKey(i); 3_$eQ`AAA  
if(header!=null) o__q)"^~-  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ZAZCvN@5  
Utility.log(header+" : "+con.getHeaderField(header)); tOw 0(-:iq  
else 3p4?-Dd|_$  
break; nlW&(cH  
} 1RA$hW@}  
}  o2  
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public void splitterStop() i1\2lh$  
{ 7VcVI? ?  
bStop = true; Z<W6Avr  
} 4Z}{hc\J  
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} @'@6vC  
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/* G:`Jrh  
**FileAccess.java v\,%)Z/  
*//文件访问(定位，写)  2p>SB/  
package NetFox; OL5HofgNm  
import java.io.*; 9 w1ONw8v  
w9$8t9$|  
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public class FileAccessI implements Serializable{ k&iDJt  
v&2@<I>  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 *`Xx_  
RandomAccessFile oSavedFile; NxO^VUD  
long nPos; ?VQLY=?  
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public FileAccessI() throws IOException AUsQj\Nm%  
{ 2pa3}6P+  
this("",0); 3n(gfQo-o  
} ++DQS9b{  
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public FileAccessI(String sName,long nPos) throws IOException `(/saq*  
{ =4<S8Cp  
oSavedFile = new RandomAccessFile(sName,"rw"); 1]Q2qs  
this.nPos = nPos; ]/Yy-T#@  
oSavedFile.seek(nPos); 'z}M[h K]  
} $?J+dB  
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92]ZiL?k  
public synchronized int write(byte[] b,int nStart,int nLen) a`b zFu{  
{ i4zV
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int n = -1; z<%g #bo  
try{ hr4ye`c j  
oSavedFile.write(b,nStart,nLen); B$TChc3B  
n = nLen; 6w"( y~c1  
} 6QLQ1k`  
catch(IOException e) ~,*YmB=Z  
{ ? x"HX|n  
e.printStackTrace (); qJ+52U|z  
} Z%5nVsm:G  
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return n; ]osx.  
} 6L,lq;  
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} %U5P}  
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/* &{E`=4T2  
**SiteInfoBean.java wD6!#t k  
*/ P}hY{y'  
package NetFox; @q+cmJKv  
| 7 m5P
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public class SiteInfoBean { J1tzH
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9^PRX  
private String sSiteURL; //Site's URL <mZrR3v'D  
private String sFilePath; //Saved File's Path eu}Fd@GO  
private String sFileName; //Saved File's Name &nqdl+|G*  
private int nSplitter; //Count of Splited Downloading File }PI35i1!t  
5#0A`QO   
/&]-I$G@  
public SiteInfoBean() HDF"]l;  
{//nSplitter的缺省值为5
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//default value of nSplitter is 5 ovd^,?ib  
this("","","",5); Z 7s;F}=  
} fJLf7+q  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) _W0OM[  
{ {*QvC g?  
sSiteURL= sURL; Opv1B2  
sFilePath = sPath; xLx"*jyL  
sFileName = sName; oGm1d{_-O  
this.nSplitter = nSpiltter; })20
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~ HK1X
  
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} $sEB'>:  
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public String getSSiteURL() /Q?~Q0{)es  
{ }{ n\tzR  
return sSiteURL; TdQ]G2  
} [{`)j  
i"L}!5  
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public void setSSiteURL(String value) {Q)dU-\  
{ su&t7
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sSiteURL = value; ZA0i)(j*Mn  
} 1Gsw-a;a  
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public String getSFilePath() >;)2NrJV  
{ %yp5DD}|  
return sFilePath; 9#uIC7M  
} wW-Ab  
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public void setSFilePath(String value) qxfLfgu^  
{ OB~C}'^$  
sFilePath = value; *C\(wL  
} ~LbS~_\C=  
wf?u(3
/%  
EZ<80G  
public String getSFileName() ,yICNtP  
{ GM](=|
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return sFileName; 1Ao6y.S  
} U;g S[8,p  
4QE=f(u;h  
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public void setSFileName(String value) !6HuFf  
{ OUzR@$  
sFileName = value; 9JPEj-3`g  
} qe$33f*  
y;nvR6)  
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public int getNSplitter() 1AF%-<`?s  
{ |jT2W  
return nSplitter; $Jp~\_X  
} HY;9?KJ'  
O2.'-  
=q+R   
public void setNSplitter(int nCount) T~Ly^|Ihz  
{ ;L~p|sF  
nSplitter = nCount; abi[jxCG  
} _ 5"+Dv  
} @QdnjX
II*  
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oQT2S>cm^  
/* (wuaxo:  
**Utility.java /[K_ &  
*/ XJgh>^R^  
package NetFox; eY,O@'"8`  
(}smW_`5  
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public class Utility { 0{+.H_f`  
_?`&JF?*  
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public Utility() icgJ;Q 5  
{ m%QSapV  
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ST Z]8cw  
} &Z;_TN
9[  
:Q_3hK  
//线程睡眠 Eectxyr?;N  
public static void sleep(int nSecond) kWhr1wR1  
{ ?9mkRd}c  
try{ mwC=o5O  
Thread.sleep(nSecond); w1`QIv  
} g(Yb^'X/  
catch(Exception e) AjkW0FB:1  
{ ,.tfWN%t\  
e.printStackTrace (); ZU{4lhe  
} =0qpVFvU  
} -!e7L>w  
iW%8/
$  
//日志 b2C`g]ibQ  
public static void log(String sMsg) :E&g%'1  
{ #
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System.err.println(sMsg); ;*2>ES  
} 0bS|fMgc  
~" i0x
 
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public static void log(int sMsg) aUU7{o_Z  
{ Cbm\h/PXl  
System.err.println(sMsg);
>&:NFq-  
} 9X$ma/P[  
} r^Zg-|gr  
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9$qm
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/* m908jI_So  
**TestMethod.java Z?5V4F:f  
*/ 'cix`l|^  
package NetFox; G<|8?6bq#  
s$D ^>0  
6!'3oN{  
public class TestMethod { {X(:jAy  
gKYfQ+  
c2t=_aAIPQ  
public TestMethod() Gs+3
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{ ///xx/weblogic60b2_win.exe a2'^8;U*_  
try{ w-wV3Q6X  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); mpPdG  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); CCBfKp  
SiteFileFetch fileFetch = new SiteFileFetch(bean); FKNMtp[`  
fileFetch.start(); /+Lfrt  
} p2Zo  
catch(Exception e){e.printStackTrace ();} Bp8'pj;~  
 ;s`sn$@  
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} ![]``g2  
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public static void main(String[] args) qlL`jWJ  
{ 3s/H2fz  
new TestMethod(); Oo"^%F~%  
} CC#;c1t  
} L#E] BY  
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