http断点续传简单实现（java)

/* U.Fs9F4M#  
**SiteFileFetch.java #('GGzL6c  
*/ \HL66%b[  
package NetFox; N *,[(q  
import java.io.*; m>^vr7  
import java.net.*; G2dPm}sZG  
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public class SiteFileFetch extends Thread { i 2 ='>  
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SiteInfoBean siteInfoBean = null; //文件信息Bean f{-,"6Y1  
long[] nStartPos; //开始位置 z .+J\  
long[] nEndPos; //结束位置 #G\Ae
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FileSplitterFetch[] fileSplitterFetch; //子线程对象 a/n~#5-  
long nFileLength; //文件长度 ETm:KbS  
boolean bFirst = true; //是否第一次取文件 ~g}blv0q+B  
boolean bStop = false; //停止标志 lXRB"
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File tmpFile; //文件下载的临时信息 r-_-/O"l  
DataOutputStream output; //输出到文件的输出流 eB9F35[  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） uMjL>YLq{?  
public SiteFileFetch(SiteInfoBean bean) throws IOException qu0
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{ i(4.7{*  
siteInfoBean = bean; y/>Nx7C0=2  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); BKK@_B"  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); mGoNT  
if(tmpFile.exists ()) 63'L58O  
{ 5R6QZVc  
bFirst = false; 7#j9"*
 
read_nPos(); nK`H;k  
} U45-R-  
else Pf~0JNnc  
{ *G[` T%g  
nStartPos = new long[bean.getNSplitter()]; Mehp]5*  
nEndPos = new long[bean.getNSplitter()]; mr,GHx  
} +hcJ!$J7  
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} tILnD1q  
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public void run() "?6R"Vk?:  
{ 3}B-n!|*  
//获得文件长度 m4^VlE,`Dh  
//分割文件 4{h^O@*g  
//实例FileSplitterFetch p7L6~IN  
//启动FileSplitterFetch线程 Jw^h<z/Ux  
//等待子线程返回 |!J_3*6$>*  
try{ 4'.]-u  
if(bFirst) ]d*O>Pm  
{ 
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nFileLength = getFileSize(); GL^ j |1  
if(nFileLength == -1) Uv(}x7e)  
{ P0rdGf 5T  
System.err.println("File Length is not known!"); knzQ)iv&&  
} ]''tuo2g8  
else if(nFileLength == -2) bd3>IWihp  
{
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System.err.println("File is not access!"); tPDB'S:&
3  
} X^C $|:  
else @h5Q?I  
{ m|[cEZxHB  
for(int i=0;i<nStartPos.length;i++) PPh1y;D  
{ !q8A!P4|'  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 0Qg%48u
 
} {"0n^
!  
for(int i=0;i<nEndPos.length-1;i++) !v*#E{r"g=  
{ Is97>aid  
nEndPos = nStartPos[i+1]; 9lX[rBZ  
} NJKk\RM@7  
nEndPos[nEndPos.length-1] = nFileLength; [n +(  
} Xm6M s<z6  
} R=W$3Ue~,  
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_X)]/A%@  
//启动子线程 vIFx'S~D  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 3ep L'My$  
for(int i=0;i<nStartPos.length;i++) Koz0Xy  
{ ktv{-WG2_  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), fVZ_*'v  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), th=45y"C  
nStartPos,nEndPos,i); pe+m%;nzR  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 72y!cK6  
fileSplitterFetch.start(); gIcPKj"8${  
} ]xhH:kW4  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), %Jn5M(myC  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); d_98%U+u  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", vf`]  
nEndPos = " + nFileLength); DE?@8k  
// fileSplitterFetch[nPos.length-1].start(); =OR&,xt  
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//等待子线程结束 }80n5X<9  
//int count = 0; ,-> P+m5  
//是否结束while循环 &HJ~\6r\  
boolean breakWhile = false; JM*rPzp  
*JaFt@ x  
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while(!bStop) #elaz8 5  
{ tI2p-d9B  
write_nPos(); Pv@;)s(-  
Utility.sleep(500);  *8 ]  
breakWhile = true; b;I!CyD  
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+Jc-9Ko\c;  
for(int i=0;i<nStartPos.length;i++) FRTvo  
{ #p=Wt&2  
if(!fileSplitterFetch.bDownOver) 4W+nSv  
{ gwYTOs^  
breakWhile = false; g:"Hg-s  
break; /zV0kW>N  
} *tT5Zt/&Sr  
} St1>J.k_  
if(breakWhile) ,I[A~  
break; 8\Eq(o}7  
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//count++; .T*7nw  
//if(count>4) W/;qMP1"-  
// siteStop(); 5TdI  
} NO)vk+   
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System.err.println("文件下载结束！"); F~O!J@4]  
} bRAf!<3  
catch(Exception e){e.printStackTrace ();} NPR{g!tK%  
} !!t@H\  
 ]cI(||x  
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//获得文件长度 k<S!|  
public long getFileSize() 0 .p $q  
{ ;d
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int nFileLength = -1; kC[nY  
try{ |zL.PS  
URL url = new URL(siteInfoBean.getSSiteURL()); Xq%!(YD|  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); KBGJB`D*  
httpConnection.setRequestProperty("User-Agent","NetFox"); uO-R:MC  
/h%MWCZWm^  
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int responseCode=httpConnection.getResponseCode(); 8%#uZG\}  
if(responseCode>=400) BF6H_g  
{ ihhnB  
processErrorCode(responseCode); 3'2}F%!Mv  
return -2; //-2 represent access is error oApI/o  
} l@YpgyqaL  
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String sHeader; #Ryu`b  
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for(int i=1;;i++) `o*g2fW!  
{ mwTn}h3N  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); >Y< y]vM:  
//Utility.log(in.readLine()); 2jx+q  
sHeader=httpConnection.getHeaderFieldKey(i); z95V 7E  
if(sHeader!=null) Bf88f<Z  
{ i&FC-{|Z  
if(sHeader.equals("Content-Length")) L=}U
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{ +=@Z5eu  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); p:ST$1 K  
break; P-`^I`r  
} osX23T~-  
} YKvFZH)  
else I_ .;nU1xA  
break;
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} +CNRSq"  
} (A&@ <  
catch(IOException e){e.printStackTrace ();} 0KT{K(  
catch(Exception e){e.printStackTrace ();} c\4n7m,y  
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Utility.log(nFileLength); JT^E`<nn  
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return nFileLength; )3B5"b,  
} rb\Ohv\  
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3]Lk}0atpL  
//保存下载信息（文件指针位置） TzL40="F  
private void write_nPos() W@$p'IBwm  
{ (\/HGxv  
try{ v|,Hd  
output = new DataOutputStream(new FileOutputStream(tmpFile)); v V^GIWK  
output.writeInt(nStartPos.length); c[y=K)<Z  
for(int i=0;i<nStartPos.length;i++) FVQWz
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{ %#QFu/l  
// output.writeLong(nPos); v,i:vT\~  
output.writeLong(fileSplitterFetch.nStartPos); kdYl>M  
output.writeLong(fileSplitterFetch.nEndPos); #1b
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} g&E_|}u4  
output.close(); '/ &"  
} :M[E-j;  
catch(IOException e){e.printStackTrace ();} 0RSa{iS*A  
catch(Exception e){e.printStackTrace ();} 4!}fC
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} >6DY3\  
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//读取保存的下载信息（文件指针位置） VD#^Xy4% r  
private void read_nPos() VYAe!{[  
{ Xp?Z;$r$  
try{ a@jP^VVk  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 49zp@a  
int nCount = input.readInt(); }\*Sf[EMD  
nStartPos = new long[nCount]; dw4)4_  
nEndPos = new long[nCount]; +tN-X'u##  
for(int i=0;i<nStartPos.length;i++) uATBt  
{ *-Yw0Y[E  
nStartPos = input.readLong(); .yP 3}Nl  
nEndPos = input.readLong(); _5LlL#)  
} F_Pd\Aq8  
input.close(); t@HE.h  
} anwn!Eqk"  
catch(IOException e){e.printStackTrace ();} 7z,M`14  
catch(Exception e){e.printStackTrace ();} XbOL/6V ^[  
} Mk9kGP%  
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private void processErrorCode(int nErrorCode) z*[Z:  
{ ?3Fo:Z`@F  
System.err.println("Error Code : " + nErrorCode); 4#YklVm
 
} si;]C~X*  
d?P aZz{4  
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//停止文件下载 &4[iC/}  
public void siteStop() 1<p"z,c  
{ E>1USKxn  
bStop = true; UK<"|2^sT  
for(int i=0;i<nStartPos.length;i++) ]\ezES  
fileSplitterFetch.splitterStop(); 3U`.:w`  
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} C/Z"W@7#;  
} TatyD**(  
//负责部分文件的抓取 }00e@a  
**FileSplitterFetch.java awK'XFk  
*/ [Bh]\I'  
package NetFox; Ja&%J:  
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import java.io.*; 2yZ6:U~  
import java.net.*; o|W? a#_\  
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public class FileSplitterFetch extends Thread { wm8x1+P  

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String sURL; //File URL .-ABo]hf  
long nStartPos; //File Snippet Start Position Dn3~8  
long nEndPos; //File Snippet End Position @ih}x  
int nThreadID; //Thread's ID $g};u[y  
boolean bDownOver = false; //Downing is over #50)DwD  
boolean bStop = false; //Stop identical 8(D}y\  
FileAccessI fileAccessI = null; //File Access interface yBj)#m5!  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException +*DX(v"BH  
{ >cNXB7]E>  
this.sURL = sURL; rh&onp O  
this.nStartPos = nStart; {ybuHC  
this.nEndPos = nEnd; iPOZ{'Z  
nThreadID = id; ka3Z5  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 8TPm[r]  
} K
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]EnaZWyO]  
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public void run() o4;Nb|kk9+  
{ dE]"^O#Mc  
while(nStartPos < nEndPos && !bStop) >nDnb4 'C  
{ ,]mwk~HeF  
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try{ $rEd5W&d!  
URL url = new URL(sURL); jZ!JXmVV  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); eLny-.i,7  
httpConnection.setRequestProperty("User-Agent","NetFox"); 0Y2^}u@5  
String sProperty = "bytes="+nStartPos+"-"; y^\#bpq&\  
httpConnection.setRequestProperty("RANGE",sProperty); @RIEO%S  
Utility.log(sProperty); c1J)yv1y  
h$k3MhYDes  
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InputStream input = httpConnection.getInputStream(); |mmG s  
//logResponseHead(httpConnection); 0gD0}nH  
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byte[] b = new byte[1024]; WN#lfn8 7  
int nRead; h.;CL#s  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) I uj=d~|>  
{ 77d`N  
nStartPos += fileAccessI.write(b,0,nRead); `Qf :PX3  
//if(nThreadID == 1) \cP'#jZz  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); }GDG$QI]K&  
} \q|PHl  
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Utility.log("Thread " + nThreadID + " is over!"); :5{@*  
bDownOver = true; k)V%.Eobf  
//nPos = fileAccessI.write (b,0,nRead); U]0)$OH5e  
} \]A;EwC4C  
catch(Exception e){e.printStackTrace ();} E$Pjp oQTf  
} As
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} M%s$F@  
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//打印回应的头信息 B
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public void logResponseHead(HttpURLConnection con) Bq]O &>\hX  
{ vfUfrk@D~  
for(int i=1;;i++) Gc!8v}[7J  
{ s;7qNwYO  
String header=con.getHeaderFieldKey(i); %*c|[7Z~V  
if(header!=null) (iOCzZ6S  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); gQ[^gPWP"  
Utility.log(header+" : "+con.getHeaderField(header)); IWo~s  
else 5MY}(w  
break; ;nKHm  
} B8AzN9v&"N  
} SM+fG:4d  
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public void splitterStop() (Q8?)  
{ |p -R9A*>h  
bStop = true; OsL%SKs|  
} LDEW00zL  
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} #7-@k-<|  
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/* nQ17E{^pR  
**FileAccess.java <yI,cM<c  
*//文件访问(定位，写) !LIfeL.4h  
package NetFox;
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import java.io.*; CEuk1$  
M:Y*Tb6w  
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public class FileAccessI implements Serializable{ w;@25= |  
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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 mzE$aFu8  
RandomAccessFile oSavedFile; B UQn+;be  
long nPos; D5!K<G?-K  
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public FileAccessI() throws IOException CQjZAv  
{ 4m~7 ~-h  
this("",0); 4:Xj-l^D  
} 25a#eDbqi  
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public FileAccessI(String sName,long nPos) throws IOException sh(kRrdY3  
{ *rn]/w8ZW  
oSavedFile = new RandomAccessFile(sName,"rw"); }d~wDg<#  
this.nPos = nPos; e(w/m(!Wny  
oSavedFile.seek(nPos); ]LBvYjMY  
} Z-t}6c'Kg  
:-u-hO5*8  
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public synchronized int write(byte[] b,int nStart,int nLen) XK%W^a*x
 
{ }or2 $\>m  
int n = -1; L+L"$  
try{ `Ixs7{&jU  
oSavedFile.write(b,nStart,nLen); #K#Mv/  
n = nLen; &#-|Yh/  
} +t>*l>[  
catch(IOException e) o'^;tLs1
5  
{ 6c2ThtL  
e.printStackTrace (); q)?p$\  
} O+o;aa6  
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return n; 4Hml.|$  
} OgK
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} gj[ >p=Wn  
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/* mNx,L+3  
**SiteInfoBean.java *9dV/TT~f[  
*/ gp$EXJ=  
package NetFox; W1?!iE~tO  
2{mY:\  
|I}A>XG  
public class SiteInfoBean { Kd/[Bs%  
rkfQr9Vc  
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private String sSiteURL; //Site's URL X:G&5  
private String sFilePath; //Saved File's Path QJ a4R  
private String sFileName; //Saved File's Name h-r6PY=i  
private int nSplitter; //Count of Splited Downloading File Nt zq"ces)  
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l5=u3r9WYC  
public SiteInfoBean() GB<R7J  
{//nSplitter的缺省值为5 zP:~O  
//default value of nSplitter is 5 V<i<0E  
this("","","",5); pxw{  
} :3a&Pb*PL  
;23=p=/h  
*|];f#^9  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) \|eJJC  
{ r7Nu>[r5  
sSiteURL= sURL; j6tP)f^tD  
sFilePath = sPath; m\6SG' X  
sFileName = sName; =$b-xsmeG  
this.nSplitter = nSpiltter; K08 iPIkQ  
uX[O,l^}  
-l-AToO4  
} <G\ <QV8W  
6sYV7w,'@  
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public String getSSiteURL() j:HH#U  
{ Lzh9DYU6  
return sSiteURL; 
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} DH\wD
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public void setSSiteURL(String value) Q&u>7_, Du  
{ Az U|p  
sSiteURL = value; MxY50^}(  
} `GvA241  
'rS'B.D  
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public String getSFilePath() T?H\&2CLT  
{ ZJ^s}  
return sFilePath; d@-wi%,^  
} YO)')&  
LIr(mB"Y0  
R]CZw;zS_  
public void setSFilePath(String value) 3hc#FmLr2b  
{ `6rrXU6|  
sFilePath = value; .r~'(g{qt  
} TT|-aS0l(u  
\4OK!6LkI  
n<{
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public String getSFileName() M} O[`Fx{W  
{ azvDvEWCQZ  
return sFileName; N\_( w:q  
} Lb!r(o>8Cb  
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=f
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public void setSFileName(String value) (.PmDBW  
{ )nhfkW=e  
sFileName = value; }g}6qCv7  
} !loO%3_)  
lNHNL a>W  
,MRvuw0P  
public int getNSplitter() GL/ KB  
{ fb/qoZ  
return nSplitter;
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} Fl<
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public void setNSplitter(int nCount) %Hh3u$Y,  
{ zgK;4 22$m  
nSplitter = nCount; hPcS, p{%  
} Bgf=\7;5  
} .
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/* B0v|{C   
**Utility.java N.jA 8X  
*/ E$w#+.QP  
package NetFox; )R~a;?T_c0  
iNX
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>ZX|4U[$P  
public class Utility { Oohq9f#!  
X\kjAMuW/*  
)PwQ^||{  
public Utility() z<t>hzl7  
{ o,J^ e_  
lO[E[c G  
`T=1<Twc  
} $}db /hY*  
9T$u+GX'  
//线程睡眠 KhrFg1|  
public static void sleep(int nSecond) *(icR  
{ Z&A0hI4d  
try{ TQ?#PRB  
Thread.sleep(nSecond); X>}@EH
T  
} bGu([VB  
catch(Exception e) )&Mq,@  
{ ]9s\_A9  
e.printStackTrace (); 9l#gMFknI  
} LaclC]yLU  
} N2T&,&,t  
&5d\~{;  
//日志 8]HY. $E  
public static void log(String sMsg) -n-Z/5~ X  
{ 6(>WGR
 
System.err.println(sMsg); 5~QTg  
} 1)'Iu`k/  
[EER4@_  
7/ t:YBR  
public static void log(int sMsg) 9ZhDZ~)p,  
{ gX_SKy  
System.err.println(sMsg); ]hL:33  
} a}dw9wU!:  
} js -2"I  
|*ReqM|_C  
3[.3dy7,Z  
/* W/=7jM   
**TestMethod.java %W&1`^Jl  
*/ 6m@0;Ht  
package NetFox; 'mJ1
3  
Bh,Q8%\6  
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public class TestMethod { @i{]4rk lv  
++0rF\&  
3 1k
 
public TestMethod() _Z$?^gn  
{ ///xx/weblogic60b2_win.exe 8+ hhdy*b  
try{ ;P8(Zf3wJb  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); sjn:O'  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Fv A8T2-v  
SiteFileFetch fileFetch = new SiteFileFetch(bean); \FXp*FbQ  
fileFetch.start(); mqw 84u  
} <%&_#<C)  
catch(Exception e){e.printStackTrace ();} GL`tOD:P"  
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7 OWsHlU  
} F 3s?&T)[G  
?<6@^X"  
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public static void main(String[] args) >4c`UW  
{ &oEyixe  
new TestMethod(); fbV@=(y?  
} e5 3,Rqi)@  
} TRy^hr8~  
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