http断点续传简单实现（java)

/* &W+G{W{3  
**SiteFileFetch.java xKST-:c+  
*/ ptyDv  
package NetFox; H)T# R?  
import java.io.*; S\g7wXH  
import java.net.*; BON""yIC   
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public class SiteFileFetch extends Thread { +1jqCW  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ;To+,`?E;q  
long[] nStartPos; //开始位置 @-@rG>y^:  
long[] nEndPos; //结束位置 h;Ud
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FileSplitterFetch[] fileSplitterFetch; //子线程对象 yn":!4U1  
long nFileLength; //文件长度 LY!3u0PnlT  
boolean bFirst = true; //是否第一次取文件 ; 9&.QR(  
boolean bStop = false; //停止标志 9Q7cUoxY  
File tmpFile; //文件下载的临时信息 OGi4m |  
DataOutputStream output; //输出到文件的输出流 | ,l=v`/  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） W<N QUf[=  
public SiteFileFetch(SiteInfoBean bean) throws IOException H&=4y) /.  
{ p z+}7  
siteInfoBean = bean; 4i\aW:_'i  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); }:l%,DBw  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 5YG@[ic  
if(tmpFile.exists ()) $4*E\G8  
{ C+]q  
bFirst = false; pF*~)e  
read_nPos(); UH,4b`b  
}
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else !na0Y  
{ hOLy*%  
nStartPos = new long[bean.getNSplitter()]; 2X;0z$  
nEndPos = new long[bean.getNSplitter()]; y#Za|nt  
} &T/q0bwd  
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} Ysc|kxLb  
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public void run() ;/^]|  
{ - Zoo)  
//获得文件长度 t
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//分割文件 ]7R&m)1
6  
//实例FileSplitterFetch GE8D3V;*V  
//启动FileSplitterFetch线程 I%Po/
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//等待子线程返回 b}?@syy8  
try{ < J<;?%
]  
if(bFirst) 0m YZ7S5g  
{ o`T<}z26
 
nFileLength = getFileSize(); ywQ!9 \  
if(nFileLength == -1) 8&A|)ur4  
{ 3|'#n[3  
System.err.println("File Length is not known!"); 07LL)v~  
} W/Z
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else if(nFileLength == -2) >?{iv1  
{ N7HbOLpM  
System.err.println("File is not access!"); Vh.;p.!e  
} OxHw1k  
else ;GgQ@s@  
{ 2*FWIHyf  
for(int i=0;i<nStartPos.length;i++) u388Wj   
{ gQpD]p%k  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); mA] 84zO  
} zEPx  
for(int i=0;i<nEndPos.length-1;i++) z1SMQLk  
{ rb}wv16?  
nEndPos = nStartPos[i+1]; 23\j1?  
} l;{N/cS  
nEndPos[nEndPos.length-1] = nFileLength; NtA|#"^  
} ZG\
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} z Jo#
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//启动子线程 q{De&Bu  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ",aT<lw.  
for(int i=0;i<nStartPos.length;i++) qp~4KukL  
{ 1nlE3Y?AV  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), sRe#{EuJ  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Q!2iOvK  
nStartPos,nEndPos,i); AR+\uD=\I-  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); s?G'l=CcKu  
fileSplitterFetch.start(); sAjKf\][  
} 5nxS+`Pn.)  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), N9JgV,`  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); \BbOljM=  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", XC/]u%n8](  
nEndPos = " + nFileLength); ?;r8SowZ7  
// fileSplitterFetch[nPos.length-1].start(); LcpyW=)}"V  

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//等待子线程结束 x(3 I?#kE  
//int count = 0; THbtu*E
l  
//是否结束while循环 32bkouq  
boolean breakWhile = false; Gkodk[VuLs  
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while(!bStop) `3sy>GU?  
{ RZ<+AX9R  
write_nPos(); %+7T
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Utility.sleep(500); Vr/` \441  
breakWhile = true; UP~WP@0F  
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for(int i=0;i<nStartPos.length;i++) -|k&L}\OB0  
{ CNpe8M=/3  
if(!fileSplitterFetch.bDownOver) HV$9b~(  
{ .^W\OJ`G  
breakWhile = false; (Xr_ np @  
break; y[^k*,= 9  
} /50g3?X,  
} ;5Wx$Yfx  
if(breakWhile) az\<sWb#  
break; S-M)MCL  
!}L~@[v,uL  
aX[1H6&=7  
//count++; x'=3&vc4  
//if(count>4) $xUzFLh=`  
// siteStop(); #A|D\IhF  
} )4'x7Qg/  
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System.err.println("文件下载结束！"); k binf  
} :p\(y  
catch(Exception e){e.printStackTrace ();} ,{uW8L  
} 6HEqm>Yau  
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//获得文件长度 ]8xc?*i8  
public long getFileSize() c4ZuW_&:  
{ T<TcV9vM  
int nFileLength = -1; _X,[]+ziu%  
try{ /slm ]'  
URL url = new URL(siteInfoBean.getSSiteURL()); *gM,x4Y  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); EI=Naq  
httpConnection.setRequestProperty("User-Agent","NetFox"); V>FT~k_"  
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int responseCode=httpConnection.getResponseCode(); f.aB?\"f6  
if(responseCode>=400) Uw2,o|=O  
{ |b$>68:  
processErrorCode(responseCode); $S6HZG:N  
return -2; //-2 represent access is error }XGMa?WR  
} Z{,GZT  
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String sHeader; n) _dH/"  
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for(int i=1;;i++) Z>(r9R3{  
{ z.2r@Psk  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); -y&v9OC2-  
//Utility.log(in.readLine()); E ;BPN  
sHeader=httpConnection.getHeaderFieldKey(i); sJ))<,e5I  
if(sHeader!=null) _KB{J7bs<a  
{ V>b2b5QAH,  
if(sHeader.equals("Content-Length")) Ow cVPu_  
{ '%zN  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); D00G1:Ft(T  
break; ^wx%CdFm'P  
} r/NSD$-n  
} [x2JFS#4  
else ia%z+:G  
break; @uI?  
} F_A%8)N  
} h4hN1<ky\  
catch(IOException e){e.printStackTrace ();} j[J5y#  
catch(Exception e){e.printStackTrace ();} YG0PxZmi  
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Utility.log(nFileLength); :]P~.PD5,  
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return nFileLength; kzZDtI)  
} S~@r  
{]wIM^$6+  
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//保存下载信息（文件指针位置） '|vD/Qf=&  
private void write_nPos() Tub1Sv>J  
{ "w}-?:# j  
try{ f4]N0  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Nls83 W  
output.writeInt(nStartPos.length); E,{GU  
for(int i=0;i<nStartPos.length;i++) {>8Pl2
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{ )y9;OA  
// output.writeLong(nPos); Y/.AUN Z  
output.writeLong(fileSplitterFetch.nStartPos); NH7`5mF$  
output.writeLong(fileSplitterFetch.nEndPos); A/q2g7My  
} yJ!OsD  
output.close(); Z[",$Lt  
} 21r== H$  
catch(IOException e){e.printStackTrace ();} T vrk^!  
catch(Exception e){e.printStackTrace ();} 2O eshkE  
} K(<$.  
' |&>/dyq  
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//读取保存的下载信息（文件指针位置） #SKfE  
private void read_nPos() Og,Y)a;=  
{ K&=D-50%  
try{ KAd_zkUA  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); +7,8w  
int nCount = input.readInt(); Zy^=fM  
nStartPos = new long[nCount]; DH 6q7"@  
nEndPos = new long[nCount]; n;wwMMBM  
for(int i=0;i<nStartPos.length;i++) I*EJHBsQ5  
{ Q,{^S,s<  
nStartPos = input.readLong(); RFw(]o,9cR  
nEndPos = input.readLong(); ,4[dLWU  
} 4&Byl85q  
input.close(); k`Nyi)AGe  
} b"I~_CL|  
catch(IOException e){e.printStackTrace ();} LO)GTyzvJ  
catch(Exception e){e.printStackTrace ();} {Fbg]'FQ
 
} ]eE 1n2  
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private void processErrorCode(int nErrorCode) ;HDZ+B  
{ "'m)VG  
System.err.println("Error Code : " + nErrorCode); 2 P=[  
} tQWWgLM  
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//停止文件下载 z v>Oh#  
public void siteStop() >OV<_(S4  
{ ~W<CE_/]k  
bStop = true; +b^]Pz5  
for(int i=0;i<nStartPos.length;i++) NUCiY\td  
fileSplitterFetch.splitterStop(); hk%k(^ekU]  
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} F|>05>8  
} (Yv{{mIy  
//负责部分文件的抓取 B MM--y@  
**FileSplitterFetch.java .}q]`<]ze  
*/ ;f:gX`"\  
package NetFox; ^i+[m  
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import java.io.*; >!L&>OOx  
import java.net.*; [E7MsX  
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public class FileSplitterFetch extends Thread { `\bT'~P  
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String sURL; //File URL VPt9QL(  
long nStartPos; //File Snippet Start Position `5q ;ssu  
long nEndPos; //File Snippet End Position yEq#Dr  
int nThreadID; //Thread's ID 5Fmav5  
boolean bDownOver = false; //Downing is over 8TE>IPjm  
boolean bStop = false; //Stop identical v?%LQKO  
FileAccessI fileAccessI = null; //File Access interface ]IZ>2!6r
  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException (luKn&826  
{ 54{q.I@n  
this.sURL = sURL; +`B'r '  
this.nStartPos = nStart; $IVwA  
this.nEndPos = nEnd; "X04mQn15  
nThreadID = id; 8Hi!kc;f6>  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 *RWm47  
} /)EY2Y'  
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[ %}u=}@  
public void run() :]PM_V|  
{ P`S@n/}  
while(nStartPos < nEndPos && !bStop) +f>cxA  
{ ]5' d&f  
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try{ ; Y"N6%
 
URL url = new URL(sURL); N>|XS ,  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); =wG+Ao  
httpConnection.setRequestProperty("User-Agent","NetFox"); <P_ea/5:|  
String sProperty = "bytes="+nStartPos+"-"; ~=En+J}*  
httpConnection.setRequestProperty("RANGE",sProperty); S|em[D[Y^  
Utility.log(sProperty); /*$hx@ih  
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InputStream input = httpConnection.getInputStream(); Y ya`&V  
//logResponseHead(httpConnection); y<- _(^  
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byte[] b = new byte[1024]; xyA-P& N  
int nRead; /6KIl  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) krB'9r<wa`  
{ x[(?#  
nStartPos += fileAccessI.write(b,0,nRead); ,+`HQdq  
//if(nThreadID == 1) `y^s
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// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); -F\qnsZ2  
} ;apzAF  
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Utility.log("Thread " + nThreadID + " is over!"); ;@3FF  
bDownOver = true; FS"eM"z  
//nPos = fileAccessI.write (b,0,nRead); a.@qGsIH  
} ~Rpm-^  
catch(Exception e){e.printStackTrace ();} ~+G#n"Pn  
} P[ r];e  
} ?wb+L  
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//打印回应的头信息 vUA0FoOp  
public void logResponseHead(HttpURLConnection con) Sv'y e  
{ l"(6]Z 4  
for(int i=1;;i++) e`K)_>^n#  
{ Zg~nlO2  
String header=con.getHeaderFieldKey(i); EH*o"N`!r  
if(header!=null) Ju2l?RrX  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); a4MZ
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Utility.log(header+" : "+con.getHeaderField(header)); 0aI;\D*Ts  
else |X19fgk  
break; k]A8% z  
} 7.Kc:7  
} bFS>)
 
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public void splitterStop() px;/8c-  
{ U]|agz>  
bStop = true; E.`U`L  
} qZv =  
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} iRV~Il#~!  
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/* H)w(q^i  
**FileAccess.java S~Z|PLtF  
*//文件访问(定位，写) oR1
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package NetFox; 5yZTcS z  
import java.io.*; -]uUYe c  
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%+>s#Q2d  
public class FileAccessI implements Serializable{ %xZG*2vc!B  
}@1q@xU  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 I){\0vb@  
RandomAccessFile oSavedFile; A- YBQPE  
long nPos; *^\HU=&  
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public FileAccessI() throws IOException $?G"GQ!.  
{ g
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this("",0); l%ayI  
} $rF=_D6  
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public FileAccessI(String sName,long nPos) throws IOException D4Al3fe  
{ `;
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oSavedFile = new RandomAccessFile(sName,"rw"); ^9OUzTF  
this.nPos = nPos; >_dx_<75&  
oSavedFile.seek(nPos); .nu @ o40  
} T<3BT  
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m  
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public synchronized int write(byte[] b,int nStart,int nLen) g]c[O*NTL  
{ |Xi%  
int n = -1; U[L9*=P;  
try{ VGHWNMT  
oSavedFile.write(b,nStart,nLen); s>k Uh  
n = nLen; 7|\@zQ h  
} `\`>0hlu  
catch(IOException e) *L6PLe  
{ PWRy7d  
e.printStackTrace (); GZS1zTwB
L  
} @vL20O.  
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return n; .:p2Tbo  
} /+*#pDx/zW  
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} 8.'#?]a  
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/*
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**SiteInfoBean.java WwH+E]^e+  
*/ SG}V[Glk  
package NetFox; JO=[YoTr  
|(moWY=  
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public class SiteInfoBean { D|Iur W1f  
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}i{sg#  
private String sSiteURL; //Site's URL dzK{ Z  
private String sFilePath; //Saved File's Path `l2O?U-@  
private String sFileName; //Saved File's Name ? J}r  
private int nSplitter; //Count of Splited Downloading File !USd9  
8
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public SiteInfoBean() &l$Q^g  
{//nSplitter的缺省值为5 %ms'n
 
//default value of nSplitter is 5 PB%-9C0  
this("","","",5); \s3]_1F;t  
} h)~=Dm  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) N#lDW~e'  
{ 'r(1N
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sSiteURL= sURL; -a*K$rnB  
sFilePath = sPath; [I4ege>  
sFileName = sName; Kvsh  
this.nSplitter = nSpiltter; hcVJBK  
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} nJPyM/p  
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public String getSSiteURL() GgaTn!mJt  
{ Dnc(l(  
return sSiteURL; 1n%?@+W  
} .B#l5pfvP  
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public void setSSiteURL(String value) zlR?,h-[3  
{ I^o!n5VM  
sSiteURL = value; |ZodlYF  
} n wI!O  
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public String getSFilePath() >~`C-K#  
{ s@MYc@k  
return sFilePath; ==i[w|  
} XqM3<~$  
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/1?R?N2>0  
public void setSFilePath(String value) @HZKc\1  
{ cRX~z  
sFilePath = value; lL]y~u  
} 4&/j|9=X  
]|<w\\^A  
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public String getSFileName() 6<K6Y5<6  
{ 4v[~r1!V  
return sFileName; g$. \
  
} @( n^T  
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public void setSFileName(String value) ?\8?%Qk  
{ j~j\\Y  
sFileName = value; hHqh{:q{v  
} Kx_h1{  
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@ 49nJi  
public int getNSplitter() VLBE'3Qg1  
{ 5k|9gICyd*  
return nSplitter; i-yy/y-N  
} @ P|LLG'  
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public void setNSplitter(int nCount) r! Ay:r  
{ ~ ihI_q"  
nSplitter = nCount; ,vW:}&U  
} pLv$\MiZ  
} ;-UmY}MU  
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!|c|o*t{  
/*
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**Utility.java _)]CzBRq\6  
*/ !x'/9^i~v  
package NetFox; Z,iHy3`  
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public class Utility { u.rY#cS,-R  
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public Utility() ePIiF_X  
{ _=|vgc  
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} M:5b4$Qh<  
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//线程睡眠 A<;SnXm  
public static void sleep(int nSecond) %kgkXc~6|x  
{ J*9$;  
try{ bTQNb!&  
Thread.sleep(nSecond); Ytg
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} aZbw]0q@o  
catch(Exception e) l3 DYg  
{ +MmHu6"1  
e.printStackTrace (); i1RiGS
 
} 3P;>XGCxZ  
} dK>7fy;mv  
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//日志 ZcYh) HD  
public static void log(String sMsg) =/\:>+p^.y  
{ QNDHOo>v  
System.err.println(sMsg); Hr$QLtr  
} "Ky; a?Y  
h,"4SSL  
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public static void log(int sMsg) s=[h?kB  
{ ,!U=|c"k)  
System.err.println(sMsg); LY+|[qka  
} |*`Z*6n  
} 0?>dCu\  
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d:yqj:  
/* ~Ch+5A;
 
**TestMethod.java *}8t{ F@k  
*/ W0}B'VS.I  
package NetFox; puT'y  
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S]E.KLR?[;  
public class TestMethod { I"KN"v^  
+>4;Zd!@d  
}CfqG?)  
public TestMethod() IIyI=WlpG  
{ ///xx/weblogic60b2_win.exe &?h,7 D;A  
try{ V%Sy"IG  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); u_rdmyq$x/  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); _SA5e3#   
SiteFileFetch fileFetch = new SiteFileFetch(bean); cp o-.  
fileFetch.start(); U)3DQ6T99  
} fNrgdfo  
catch(Exception e){e.printStackTrace ();}
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i E CrI3s  
} ~/*MY  
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public static void main(String[] args) &d|r~NhP  
{ H@l}WihW  
new TestMethod(); !fj(tPq  
} ZI=v.wa  
} <ZB1Vi9}8  
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