http断点续传简单实现（java)

/* &r,)4q+  
**SiteFileFetch.java `/?'^A%Ik  
*/ 6`vW4]zu  
package NetFox; m;A[2 6X  
import java.io.*; L^zh|MEyzk  
import java.net.*; hsT&c|  
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MTN*{ug2:  
public class SiteFileFetch extends Thread { HOF=qE*p  
=LODX29  
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SiteInfoBean siteInfoBean = null; //文件信息Bean i(OeE"YA  
long[] nStartPos; //开始位置 6B%  h  
long[] nEndPos; //结束位置 !A1~{G2VL_  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ? |#dGk g  
long nFileLength; //文件长度 $PI9vyS  
boolean bFirst = true; //是否第一次取文件 YRCs&tgs  
boolean bStop = false; //停止标志 mU~&oU  
File tmpFile; //文件下载的临时信息 N'-[>w7vK2  
DataOutputStream output; //输出到文件的输出流 U$<" .q  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） Q
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public SiteFileFetch(SiteInfoBean bean) throws IOException 2P)O 0j\/  
{ `uUzBV.FR  
siteInfoBean = bean; rmo\UCD  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); dGi HO  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 5&h">_j  
if(tmpFile.exists ()) N>,`TsUwW  
{ "DA%vdu  
bFirst = false; _Gf-s51s  
read_nPos(); M0~%[nX  
} Aq*?Q/pV  
else :enR8MS  
{ <9piKtb|L  
nStartPos = new long[bean.getNSplitter()]; lSW'qgh  
nEndPos = new long[bean.getNSplitter()]; IM7<z,*oF  
} z#ki# o  
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} 6 Bdxdx*zt  
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public void run() eU@Mv5&6  
{ 5 7t.Ud  
//获得文件长度 1kw*Q:  
//分割文件 )dqNN tS  
//实例FileSplitterFetch mJ=V<_  
//启动FileSplitterFetch线程 \wk;Bo  
//等待子线程返回 =JgR c7  
try{ R ZQH#+*t}  
if(bFirst) zSQy   
{ j6Sg~nRh  
nFileLength = getFileSize(); <+-n lK4  
if(nFileLength == -1) z<mN-1PM7&  
{ ]X77?Zz9  
System.err.println("File Length is not known!"); N0-J=2  
} N0Y4m_dm*  
else if(nFileLength == -2) y.J>}[\&x  
{ }8#Ed;%K  
System.err.println("File is not access!"); bT&{8a  
} `=P_ed%&'  
else Mmu#hb|W  
{ FZ?eX`,  
for(int i=0;i<nStartPos.length;i++) BZHoRd{EH  
{ ]W1
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); Xd5s8C/}  
} o2U5irU  
for(int i=0;i<nEndPos.length-1;i++) <j>;5!4!}  
{ )\EIXTZY=  
nEndPos = nStartPos[i+1]; r6'dEa  
} _1qR1<V  
nEndPos[nEndPos.length-1] = nFileLength; 3MFTP5~  
} @R50M (@W  
} #` gu<xlW  
Xi) ;dcNJ  
N+B!AK0.  
//启动子线程 HXSryjF?  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; "q+Z*  
for(int i=0;i<nStartPos.length;i++) g.@[mf0r  
{
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fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), _^#eO`4"  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), +cqUp6x.  
nStartPos,nEndPos,i); q
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Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); h!%y,4IBR  
fileSplitterFetch.start(); m2jts(stp  
} 6bhb_U'f  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), < $e#o H  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 69)"T{7  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", &Wcz~Gx3Q  
nEndPos = " + nFileLength); Se'SDJl=  
// fileSplitterFetch[nPos.length-1].start(); 4n6AK
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=<3HOOC  
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//等待子线程结束 1Ub=RyB  
//int count = 0; 9QXsbd6  
//是否结束while循环 aH?Ygzw  
boolean breakWhile = false; <_<zrXc]  
X+N5iT  
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while(!bStop) eG!ma`v  
{  ^AaE$G&:  
write_nPos(); *)-@'{]uB  
Utility.sleep(500); 452kE@=49  
breakWhile = true; LdG?kbJ&y  
\WFcb\..  
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for(int i=0;i<nStartPos.length;i++) bRy(`  
{ ;9mRumLG"  
if(!fileSplitterFetch.bDownOver) UTKyPCfj  
{ zHZfp_I  
breakWhile = false; [znN'Fg:"  
break; V<S6a
  
} G&^8)S@1  
} <i</pA  
if(breakWhile) !>> A@3  
break; %K|f,w=m  
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//count++; 7WS$fUBi  
//if(count>4) v
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// siteStop();
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} tt?`,G.(]  
E-.X%xfO  
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System.err.println("文件下载结束！"); JS^DyBXc  
} G`O*A
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catch(Exception e){e.printStackTrace ();} rP7 QW)NF  
} c86KDEF  
*{#C;"  
!'^l}K>  
//获得文件长度 4jebx jZ  
public long getFileSize() k-=lt\?  
{ 6R<+_e+v  
int nFileLength = -1; wB0vpt5f  
try{ 
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URL url = new URL(siteInfoBean.getSSiteURL()); ~9
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); A)"L+Yu5  
httpConnection.setRequestProperty("User-Agent","NetFox"); Dh2Cj-| ~  
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int responseCode=httpConnection.getResponseCode(); 27ZqdHd  
if(responseCode>=400)  FNH)wk  
{ nL=+`aq_  
processErrorCode(responseCode); Yft [)id  
return -2; //-2 represent access is error C}mhnU@  
} Pb?vi<ug+  
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String sHeader; mN]WjfII  
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for(int i=1;;i++) lb't
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{ C_Q3
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//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); A_S7z*T  
//Utility.log(in.readLine()); gjG SI'M0B  
sHeader=httpConnection.getHeaderFieldKey(i); $3 -QM  
if(sHeader!=null) Anyy
 
{ {guOAT-w  
if(sHeader.equals("Content-Length")) @,.D]43  
{ _J6 Xq\  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); kh.P)h'9  
break; MZQDFuvDxZ  
} W.[!Q`  
} g&y (-  
else <A Hzs  
break; mTtaqo_Bh  
} ;L
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} Wjl2S+Cc  
catch(IOException e){e.printStackTrace ();} Dch\k<Te  
catch(Exception e){e.printStackTrace ();} o0`']-)*2  
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Utility.log(nFileLength); %p
 
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return nFileLength; K9Mz4K_  
} 2YZ>nqy  
|D-[M_T5  
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//保存下载信息（文件指针位置） )TiM>{  
private void write_nPos() /_m)D;!y  
{ ]$L5}pE3  
try{ (o B4*  
output = new DataOutputStream(new FileOutputStream(tmpFile)); S=) c7t?a  
output.writeInt(nStartPos.length); *1["x;A  
for(int i=0;i<nStartPos.length;i++) kVWcf-
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{ E& 6I`8  
// output.writeLong(nPos); z7IJSj1gQI  
output.writeLong(fileSplitterFetch.nStartPos); xD&n'M]  
output.writeLong(fileSplitterFetch.nEndPos); ;G8H'gM07  
} .o`Io[io  
output.close(); RVm-0[m}  
} T>% 5<P
 
catch(IOException e){e.printStackTrace ();} hJxL|5Uo  
catch(Exception e){e.printStackTrace ();} MwRLv,&"  
} *h0D,O"0  

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//读取保存的下载信息（文件指针位置） f#:3TJV  
private void read_nPos() Y}R$RDRL  
{ M1k{t%M+S  
try{ 3lf=b~Zi
)  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 4X!/hI=jq  
int nCount = input.readInt(); 7BE>RE=)  
nStartPos = new long[nCount]; ux=w!y;}  
nEndPos = new long[nCount]; 'j`=if
 
for(int i=0;i<nStartPos.length;i++) !O\82d1P  
{ vDp8__^  
nStartPos = input.readLong(); G"r1+#  
nEndPos = input.readLong(); _~'=C#XI)  
} hCi60%g/n  
input.close(); _zR+i]9   
} +Z
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catch(IOException e){e.printStackTrace ();} (of#(I[
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catch(Exception e){e.printStackTrace ();} qrb[-|ie&  
} T-'OwCB1q  
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private void processErrorCode(int nErrorCode) g{7.r-uu  
{ R4[N:~Z$|  
System.err.println("Error Code : " + nErrorCode); _('=b/  
} .e
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ST|x23|O]  
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//停止文件下载 g?c xp+  
public void siteStop() NN%*b yK  
{ h){0rX@:&  
bStop = true; ?k+xSV  
for(int i=0;i<nStartPos.length;i++) [u =+3b  
fileSplitterFetch.splitterStop(); X
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} cutuDZ  
} {AhthR%(1  
//负责部分文件的抓取 U'k*_g
 
**FileSplitterFetch.java A`N,  
*/ TEP,Dq  
package NetFox; ;dkYf24  
T]^62(So  
)%`c_FL@N=  
import java.io.*; &DS/v)]  
import java.net.*; xzdf^Ce  
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public class FileSplitterFetch extends Thread { _:ReN_0  
z{8bvuE  
KWq+PeB5TS  
String sURL; //File URL dph{74Dc  
long nStartPos; //File Snippet Start Position '3R`lv   
long nEndPos; //File Snippet End Position OyStqi  
int nThreadID; //Thread's ID )\1QJ$-M&  
boolean bDownOver = false; //Downing is over U#0Q)  
boolean bStop = false; //Stop identical 46}g7skD  
FileAccessI fileAccessI = null; //File Access interface ^a/gBC82x  
]MqMQLG0t  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException H[NSqu.s  
{ o$wEEz*4  
this.sURL = sURL; 7z%L*z8V  
this.nStartPos = nStart; C>ICu*PW  
this.nEndPos = nEnd; a]$1D!Anc  
nThreadID = id; jrCfW
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fileAccessI = new FileAccessI(sName,nStartPos);//定位 ML}J\7R  
} pf]xqhL  
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public void run() %h hf
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{ ]RwpX ^ 1  
while(nStartPos < nEndPos && !bStop) ,bZL C  
{ ,dv+p&Tz2  
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try{ {yBs7[Wn  
URL url = new URL(sURL); 1m'k|Ka  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); On8v//=&  
httpConnection.setRequestProperty("User-Agent","NetFox"); "x#-sZ=  
String sProperty = "bytes="+nStartPos+"-"; >>QY'1Eu  
httpConnection.setRequestProperty("RANGE",sProperty); T tfo^ksw  
Utility.log(sProperty); eJrQ\>z]V&  
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InputStream input = httpConnection.getInputStream(); 0B[="rTS7#  
//logResponseHead(httpConnection); v|Pv 03%?7  
9d>-MX'  
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byte[] b = new byte[1024]; aR[JD2G  
int nRead; uY{|szC^2  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 2\)xpOj  
{ mWv3!i;G<s  
nStartPos += fileAccessI.write(b,0,nRead); hM_lsc  
//if(nThreadID == 1) 99]R$eT8  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 'HO$C,1]  
} kF3k7,.8&  
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Utility.log("Thread " + nThreadID + " is over!"); b\ X@gq  
bDownOver = true; ~]nRV *^  
//nPos = fileAccessI.write (b,0,nRead); @tF\p  
} \|n- O=}=2  
catch(Exception e){e.printStackTrace ();} gGR"Z]DBk  
} EHSlK5bD,  
} OP;v bZ  
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//打印回应的头信息 7( #:GD  
public void logResponseHead(HttpURLConnection con) T*I{WW  
{ hl;u'_AB  
for(int i=1;;i++) seba9y  
{ CYt?,qk-r  
String header=con.getHeaderFieldKey(i); |a8iZ9/D6  
if(header!=null) J;S (>c  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); &PL8|w  
Utility.log(header+" : "+con.getHeaderField(header)); !:)s"|=  
else 3D6RLu
  
break; Zj_b>O-V  
} # '=a=8-$  
} jY&k  
u
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public void splitterStop() QER?i;-wb  
{ )"qa kT  
bStop = true; c& <Fr[AK  
} dLH(D: `  
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*=) cQeJ  
} E!;SL|lj.  
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/* N[?N5
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**FileAccess.java OwuE~K7b{  
*//文件访问(定位，写) aasoW\UG  
package NetFox; 5b5x!do  
import java.io.*; 6=kEyJT'  
L]yS[UN$  
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public class FileAccessI implements Serializable{ j 'FVz&  
?}qttj  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 '|ad_M  
RandomAccessFile oSavedFile; y~(h>gi,x  
long nPos; Y&`=jDI  
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public FileAccessI() throws IOException  JR'  
{ q~ tz? T_  
this("",0); 88Ey12$  
} "_P;2N6  
0*VWzH   
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public FileAccessI(String sName,long nPos) throws IOException Qd)q([  
{ uOKCAqYa  
oSavedFile = new RandomAccessFile(sName,"rw"); zy?.u.4L  
this.nPos = nPos; N%kt3vmQ_  
oSavedFile.seek(nPos); zofa-7'Bn  
} K'55O&2  
#:jHp44J  
V4hiGO[  
public synchronized int write(byte[] b,int nStart,int nLen)  Fiv3 {.  
{ ,ZaRy$?  
int n = -1; {SOr#{1z*  
try{ 
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oSavedFile.write(b,nStart,nLen); R$v[!A+:'  
n = nLen; >~#yu&*D  
} B`YTl~4  
catch(IOException e) LU \i0|i|  
{ #r$cyV!k  
e.printStackTrace (); ks&*O!h  
} Ki4r<>\l{H  
F7A=GF'  
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return n; %}[i'rT>  
} AmvEf  
}\hVy(\c  
6wPaJbRtaM  
} EH$1fvE  
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26e]`]!SU  
/* i=ea ?eT`  
**SiteInfoBean.java {mm)ay|M  
*/ Bz^jw>1b  
package NetFox; 5:\},n+VE  
67VL@ ]  
# Nk;4
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public class SiteInfoBean { *7:>EP  
Nc1"g1JR  
&@G:G(  
private String sSiteURL; //Site's URL PZ2;v<  
private String sFilePath; //Saved File's Path E8!e:l =Q  
private String sFileName; //Saved File's Name d.3E[AJa(  
private int nSplitter; //Count of Splited Downloading File eS{!)j_^  
k\wW##=v  
"76]u)  
public SiteInfoBean() <W|3\p6  
{//nSplitter的缺省值为5 H6kR)~zhf  
//default value of nSplitter is 5 <S\jpB  
this("","","",5); 8N!b>??  
} " f <Z=c  
gGvz(R:
y  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) J\/cCW-rF  
{ w&X<5'GM  
sSiteURL= sURL; lun#^J  
sFilePath = sPath; 1uG"f<TsR  
sFileName = sName; 7zA'ri3w  
this.nSplitter = nSpiltter; 
^.1)};i  
={_C&57N1  
!\"EFVH  
} qUh2hz:  
-jW.TT h]  
7[w,:9& }  
public String getSSiteURL() TBs|r#  
{ 6{
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return sSiteURL; ,
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T,  
} C^3 <={  
}
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5
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public void setSSiteURL(String value) S-P/+K6  
{ e_#._Pi  
sSiteURL = value; 8hXl%{6d3  
} RzxNbeki[W  
;
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public String getSFilePath() $Oq^jUJ  
{ PjZvQ\Z  
return sFilePath; ?<V?wsp  
} b$4"i XSQ  
XnDUa3  
K:!"+q  
public void setSFilePath(String value) GU4'&#  
{ 4P'*umJi  
sFilePath = value; !5.8]v
 
} XJ;D=~  
1s%#$ 7  
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public String getSFileName() jB`,u|FG  
{ `rgn<I"  
return sFileName; D'7SAFOM  
}
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}0eF~>Df  
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public void setSFileName(String value) lH-/L(h2  
{ Z9:
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sFileName = value; M|6A0m#Q  
} [.m`+  
Yb+yw_5  
\
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public int getNSplitter() >[MX:Yh  
{ 0>C T=(A  
return nSplitter; n.T&}ZPz\v  
} ,#Iu 7di  
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public void setNSplitter(int nCount) bW$J~ynM  
{ 6,)[+Bl  
nSplitter = nCount; Q
7  
} (mgS"zPS  
} |y&*MTfV4L  
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/* cJN7bA{  
**Utility.java XaCX!Lr,  
*/ 61.Brp.eP  
package NetFox; J!0DR4=Xi  
!6BW@GeF]  
#i@;J]x(  
public class Utility { gGr^@=;YC  
Px$/ _`H  
0TCBQ~"  
public Utility() {aY%gk?y#>  
{ 1xD=ffM>8N  
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"^4_@ oo  
} aEM%R<e  
s}j{#xT  
//线程睡眠 A9f)tqbc  
public static void sleep(int nSecond) uxW~uEh  
{ Z9MdD>uwi  
try{ %C$%!C  
Thread.sleep(nSecond); M4zm,>?K  
} Ey_" ~OB  
catch(Exception e) ZYI{i?Te#  
{ /]=C{)8  
e.printStackTrace (); wp#'nO  
} 9S-Z&2L  
} bvS(@  
s~>d:'k7|  
//日志 AmaT0tzJC  
public static void log(String sMsg) ]e^c=O`$  
{ }R1
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System.err.println(sMsg); s>0't  
} vI2^tX9  
j/>$,   
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public static void log(int sMsg) p;._HJ(  
{ :z4)5= 6M  
System.err.println(sMsg); q<\
,  
} 3AQZRul  
} [onGNq?#  
lp<g\  
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/* lLp^Gt^}w(  
**TestMethod.java "$N#p5  
*/ ;u;#g  
package NetFox; qR(\5}  
(IC]?n}  
n;(\5{a  
public class TestMethod { ]F;
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o=21|z  
qp/v^$EA  
public TestMethod() BnCbon)  
{ ///xx/weblogic60b2_win.exe Q,p}:e  
try{ Db)?i?o}t  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); *"D3E7AO  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 5"HVBfFk  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ?*E'^~,H)  
fileFetch.start(); t"k*PA  
} Pdt6nzfr  
catch(Exception e){e.printStackTrace ();} ZkAU17f  
&GlwC%$S  

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} _{r=.W+w  
@c<3b2  
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public static void main(String[] args) >?6&c  
{ !OBEM1~ 1  
new TestMethod(); q0$ !y!~  
} (>VX-Y/  
} u#Z#)3P  
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