http断点续传简单实现（java)

/* ,
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**SiteFileFetch.java 8W[QV  
*/ e@L+z  
package NetFox; n`vqCO7@'  
import java.io.*; e&<#8;2X  
import java.net.*; oT\B-lx  
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public class SiteFileFetch extends Thread { FK }x*d  
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SiteInfoBean siteInfoBean = null; //文件信息Bean f*NtnD=rJ  
long[] nStartPos; //开始位置   
long[] nEndPos; //结束位置 b?B"u^b!  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 vTh-I&}:  
long nFileLength; //文件长度 d,8V-Dk+p  
boolean bFirst = true; //是否第一次取文件 `axNeqM  
boolean bStop = false; //停止标志 3P^eD:) w  
File tmpFile; //文件下载的临时信息 `i
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DataOutputStream output; //输出到文件的输出流 n!ea)+^  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） u32wS$*8  
public SiteFileFetch(SiteInfoBean bean) throws IOException W=GNo9:  
{ feQ_dA q  
siteInfoBean = bean; o!sxfJKl  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); rYJt;/RtR}  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); jcXb@FE6  
if(tmpFile.exists ()) L7X._XBO[  
{ TcauCL  
bFirst = false; UF D_  
read_nPos(); ;=_<\2  
} 9oKRu6]D-  
else *>$'aQ  
{ sFC1PdSk4T  
nStartPos = new long[bean.getNSplitter()]; A>R ^iu  
nEndPos = new long[bean.getNSplitter()]; 43,- t_jV  
} K*7*`6iU  

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} $`{}4,5M  
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public void run() Vn=J$Uv0  
{ qW;nWfkYC
 
//获得文件长度 XLEA|#  
//分割文件 o~mY,7@a  
//实例FileSplitterFetch >Q[]i4*A  
//启动FileSplitterFetch线程 ;#~rd8Z52  
//等待子线程返回
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try{ q'C'S#qqn  
if(bFirst) q^"P_pV\  
{ .zBSjh_=H  
nFileLength = getFileSize(); n." j0kc7=  
if(nFileLength == -1) #uuwzE*M_  
{ }eEF/o  
System.err.println("File Length is not known!"); 6&.[:IHw  
} '9{H(DA  
else if(nFileLength == -2) I/XVo2
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{ G1$DVGo  
System.err.println("File is not access!"); ZZ[5Z=te?  
} <%qbU-  
else 9#O"^.Z !  
{ "%,zB_ng\<  
for(int i=0;i<nStartPos.length;i++) b:Rl }"a  
{ %#/7Tl:  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); nzhQ\'TC  
} rf1-E57#  
for(int i=0;i<nEndPos.length-1;i++) i]8zZRe  
{ yK{;72  
nEndPos = nStartPos[i+1]; p
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} >'Y]C\  
nEndPos[nEndPos.length-1] = nFileLength; #<yR:3  
} mfeyR  
} i+21tG$  
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//启动子线程 @HIC i]  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; N@tzYD|hA  
for(int i=0;i<nStartPos.length;i++) /vsQ <t;~  
{ J*a`qU   
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), `=q)-y_C  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), +SUQRDF@i  
nStartPos,nEndPos,i); ZLE4XB]  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 1ub03$pL;  
fileSplitterFetch.start(); +~w '?vNc  
} Q?W]g%:)  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ={#r/x  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ApU5,R0  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", owmA]f  
nEndPos = " + nFileLength); l~F,i n.  
// fileSplitterFetch[nPos.length-1].start(); 0fi+tc30  
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//等待子线程结束 k9yA#
 
//int count = 0; <Ni]\-*  
//是否结束while循环 }{j[  
boolean breakWhile = false; 47ir QK*  
5:^dyF&sm{  
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while(!bStop) )7c^@I;7  
{ zzq/%jki  
write_nPos(); ?w3f;v  
Utility.sleep(500); z'fGHiX7.0  
breakWhile = true; t?YGGu^  
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for(int i=0;i<nStartPos.length;i++) b*?="%eE(  
{ sNS!/  
if(!fileSplitterFetch.bDownOver) !{Y$5)Xh`]  
{ Hr96sN.R   
breakWhile = false; "}Ya.  
break; h r*KDT^!  
} 7th&C,
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} ~3/>;[!  
if(breakWhile) a/>={mbKi  
break; A/BL{ U}  
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//count++; I-fs*yzj;8  
//if(count>4) pX6OhwkTK  
// siteStop(); auL?Hb  
} =0x[Sa$&,  
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System.err.println("文件下载结束！"); *K-,<hJ#L  
} dIIsO{Zqv  
catch(Exception e){e.printStackTrace ();} G}}oeS  
} >Pbd#*  
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//获得文件长度 <t]i'D(K  
public long getFileSize() r&Za*TD^  
{ NoDq4>   
int nFileLength = -1; ]7'Q2OU7  
try{ ed>_=i  
URL url = new URL(siteInfoBean.getSSiteURL()); PJh\U1Z  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); $\m=-5 0-  
httpConnection.setRequestProperty("User-Agent","NetFox"); >{npg2  
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int responseCode=httpConnection.getResponseCode(); %# J8
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if(responseCode>=400) %Cb8vYz~  
{ qXP)R/~OZ  
processErrorCode(responseCode); 1`B5pcuI  
return -2; //-2 represent access is error Tje =vI  
} < ~x5{p  
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String sHeader; !>9*$E |  
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for(int i=1;;i++) .R biF  
{ |K/#2y~  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); >:Q:+R;3o  
//Utility.log(in.readLine()); I
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sHeader=httpConnection.getHeaderFieldKey(i); J>XaQfzwU  
if(sHeader!=null) l<z[)fE{uS  
{ +S0A`rL  
if(sHeader.equals("Content-Length")) `C_#EU-  
{ q)<5&|V  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); MH{vFA4:,  
break; ( 9dV%#G\  
} --",}%-  
} nb0<.ICF%R  
else 5g/^wKhKG  
break; K2:r
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} dA\>z[n=  
} rYN`
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catch(IOException e){e.printStackTrace ();} k_O"bsI)  
catch(Exception e){e.printStackTrace ();} j(Q$frI  
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.
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Utility.log(nFileLength); a,&Kvh  
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return nFileLength; fa5($jJ&  
} hO{@!H$l  
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//保存下载信息（文件指针位置） },[S9I`p  
private void write_nPos() uvD6uIW<  
{ %,~; w0  
try{ JR7~|ov  
output = new DataOutputStream(new FileOutputStream(tmpFile)); $.V(_  
output.writeInt(nStartPos.length); as o8  
for(int i=0;i<nStartPos.length;i++)  LFGu|](  
{ ,,BNUj/:  
// output.writeLong(nPos); lh?mN3-*  
output.writeLong(fileSplitterFetch.nStartPos); 2Ni{wg"  
output.writeLong(fileSplitterFetch.nEndPos); V~e1CZ(2X  
} 0#Rj[J;kh  
output.close(); zS?i@e $  
} :
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catch(IOException e){e.printStackTrace ();} pklcRrx,a  
catch(Exception e){e.printStackTrace ();} )S8q.h  
} >KGQ#hnH  
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//读取保存的下载信息（文件指针位置） =7Tbu'O;  
private void read_nPos() dVe3h.
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{ K7e<hdP_#  
try{ %qja:'k  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); jGt'S{  
int nCount = input.readInt(); n!HFHy2  
nStartPos = new long[nCount]; DgOoEHy[  
nEndPos = new long[nCount]; L=HL1Qe$G]  
for(int i=0;i<nStartPos.length;i++) A=h`Z^8\B  
{ T("Fh}  
nStartPos = input.readLong(); @&EE/j^  
nEndPos = input.readLong(); &Lq @af#  
} {p6",d."N&  
input.close(); }$AC0  
} O8dD
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catch(IOException e){e.printStackTrace ();} rM>&!?y+  
catch(Exception e){e.printStackTrace ();} {'r(P&  
} O5k's  
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private void processErrorCode(int nErrorCode) BAt2m-  
{ cMK6  
System.err.println("Error Code : " + nErrorCode); #NL1N_B  
} !L3Bvb;Q  
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//停止文件下载 @ZX{q~g!  
public void siteStop() = b)q.2'#  
{ Ud{-H_m+  
bStop = true; r-Dcc;+=Q  
for(int i=0;i<nStartPos.length;i++) NPS=?5p>  
fileSplitterFetch.splitterStop(); \nxt\KD  
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} MX9q )(:  
} wlKL|N  
//负责部分文件的抓取 lfI[
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**FileSplitterFetch.java Wg}#{[4  
*/ Q g"{F},4  
package NetFox; u $sX6  
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import java.io.*; xX"?3%y>  
import java.net.*; possM'vC  
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public class FileSplitterFetch extends Thread { E+7S:B  
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String sURL; //File URL CZ&TUE|:DA  
long nStartPos; //File Snippet Start Position '0o`<xW  
long nEndPos; //File Snippet End Position ^kXDEKm  
int nThreadID; //Thread's ID |fzo$Bq  
boolean bDownOver = false; //Downing is over 0p[$8SCJ  
boolean bStop = false; //Stop identical nh E!Pk  
FileAccessI fileAccessI = null; //File Access interface txL5'mK  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException %[p[F~Z^Z  
{ =6+BBD  
this.sURL = sURL; G:@gO2(D  
this.nStartPos = nStart; sV77WF  
this.nEndPos = nEnd; XhIgzaGVu  
nThreadID = id; ^ePSI|EW  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 0kiW629o  
} Rw. Uz&  
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public void run() a7d782~  
{ }RoM N$r  
while(nStartPos < nEndPos && !bStop) WQK#&r*  
{ ;^ /9sLW?#  
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try{ ?Rl*
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URL url = new URL(sURL); M_XZOlW5  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); !-;Me&"I=`  
httpConnection.setRequestProperty("User-Agent","NetFox"); h.7 1O"N  
String sProperty = "bytes="+nStartPos+"-"; MA1,;pv6  
httpConnection.setRequestProperty("RANGE",sProperty); %{Ls$Y)  
Utility.log(sProperty); >w*"LZjTTK  
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InputStream input = httpConnection.getInputStream(); _6(zG.Fg  
//logResponseHead(httpConnection); {+r?gJ  
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byte[] b = new byte[1024]; >?tcL*  
int nRead; JT:9"lmJz,  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) UPgZj\t%{  
{ "1[N;|xa  
nStartPos += fileAccessI.write(b,0,nRead);
+"SBt}1  
//if(nThreadID == 1) o86}NqK  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); eFeeloH?e*  
} VK
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Utility.log("Thread " + nThreadID + " is over!"); )v|a:'%K_  
bDownOver = true; @lj
 
//nPos = fileAccessI.write (b,0,nRead); Cu`ZgKLQ  
} fB:M'A'  
catch(Exception e){e.printStackTrace ();} kQH!`-n:T  
} ~q1s4^J  
} P,v}Au( UI  
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//打印回应的头信息 F^aD!O ~  
public void logResponseHead(HttpURLConnection con) 2R5]UR S  
{ HML6<U-eS  
for(int i=1;;i++) P/y-K0u  
{ o%|1D'f^  
String header=con.getHeaderFieldKey(i); i>rn!?b  
if(header!=null) dIf Jr}ih  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); lLg23k{'  
Utility.log(header+" : "+con.getHeaderField(header)); ec3('}X  
else .*zQ\P  
break; =*(d+[_  
} Onc!5L  
} 2dq{n.cgs  
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public void splitterStop() Z os~1N]3  
{ KS|$_-7u  
bStop = true; }5]NUxQ_  
} d3![b1  
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} :4Y|%7[  
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/* %v|,-B7Yx  
**FileAccess.java F(w>lWs;  
*//文件访问(定位，写) 4s"HO/  
package NetFox; O-G@To3\  
import java.io.*; iA< EJ  
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public class FileAccessI implements Serializable{ 0qTa@y  
'Gc6ZSLM  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ~bwFQYY=  
RandomAccessFile oSavedFile; 8=SNLO  
long nPos; Xr~r`bR=  
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public FileAccessI() throws IOException :,7VqCh3@  
{ =]^*-f}J9  
this("",0); "Fke(?X'  
} Z2`e*c-[E  
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public FileAccessI(String sName,long nPos) throws IOException :Ert57@l  
{ xA-G&oC]<T  
oSavedFile = new RandomAccessFile(sName,"rw"); {:rU5 !n  
this.nPos = nPos; ())|x[>JS+  
oSavedFile.seek(nPos); ud.S, 8Sy  
} $b8>SSz  
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public synchronized int write(byte[] b,int nStart,int nLen) ;m&f Vp  
{ }t
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int n = -1; b
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try{ H`".L^  
oSavedFile.write(b,nStart,nLen); 2.x3^/  
n = nLen; l9<+4rK2  
} `^6}Dn  
catch(IOException e) p]>bN  
{ d82IEhZ#  
e.printStackTrace (); w|M?t{  
} S=my;M-  
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return n; T@z$g  
} &d*9#?9  
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} ]]]7"a  
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/* Vxw?"mhP  
**SiteInfoBean.java *Lufz-[1  
*/
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package NetFox; 6qw_|A&g  
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public class SiteInfoBean { ~
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private String sSiteURL; //Site's URL ))MP]j9 T  
private String sFilePath; //Saved File's Path BY 1~\M  
private String sFileName; //Saved File's Name S#""((U$  
private int nSplitter; //Count of Splited Downloading File CsE|pXVG  
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public SiteInfoBean() -7yX>Hjl  
{//nSplitter的缺省值为5 :<jf}[w!  
//default value of nSplitter is 5 J6Kfz~%  
this("","","",5); D@3|n
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} q2SkkY$_]y  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ^yb_aCw  
{ yn=1b:kid  
sSiteURL= sURL; fW\u*dMMZE  
sFilePath = sPath; 'DIE#l`  
sFileName = sName; 85X^T]zo  
this.nSplitter = nSpiltter; 5 )C~L]  
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} 0zfrx-'zN  
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public String getSSiteURL() ?Jma^ S  
{ sS0psw1  
return sSiteURL; X`vDhfh>N  
} )45,~+XX  
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public void setSSiteURL(String value) O35f5Kz  
{ :3G9YjzC}  
sSiteURL = value; G/D{K$=t~  
} \mycn/e  
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public String getSFilePath() Z-~^)lo  
{ kP|!!N  
return sFilePath; L Y
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} q
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public void setSFilePath(String value) kBT cND|  
{ j9qN!.~mM  
sFilePath = value; b/G0EcRw+  
} "y`?KY$[N  
%Wc-.ER  
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public String getSFileName() fHgfI@{=j  
{ v|e\o~2D`  
return sFileName; NN$`n*;l  
} &wjOb  
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public void setSFileName(String value) w8on3f;6n#  
{ UC0 yrV  
sFileName = value; O-|3k$'\z  
} ~q9RZ#g13J  
4gZN~_AI<  
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public int getNSplitter() ' ZB%McS  
{ f]hW>-B(q  
return nSplitter; (Hsf
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} .!`j3W]  
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public void setNSplitter(int nCount) NT nn!k  
{ ZqhINM*Rm  
nSplitter = nCount; k82'gJ;MC=  
} n2QD*3i  
} >SzTZ3!E  
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/* *zx;81X=  
**Utility.java v14[G@V~\  
*/ x_Z~k  
package NetFox; 6ZM<M7(V  
@3G3l|~>  
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public class Utility { ~!uK;hI  
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public Utility() _Ih~'Y Fd  
{ abK/!m[q  
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} WT0U)x( m5  
\0:l9;^4  
//线程睡眠 F |GWYw'%  
public static void sleep(int nSecond) `aUA_"f  
{ i^W\YLE  
try{ .d*vfE$  
Thread.sleep(nSecond); 2{qoWys8[  
} aJfW75C  
catch(Exception e)
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{ #8(@a Y  
e.printStackTrace (); ugL$W@   
} rN*4Y  
} "44X'G8N  
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//日志 \t(/I=E8/  
public static void log(String sMsg) xE}q(.]  
{ rVO+ vhih  
System.err.println(sMsg); ClEtw  
}
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N@
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public static void log(int sMsg) R"tLu/Sn  
{ y<gmp
 
System.err.println(sMsg); 4iw+3 Q|  
} +[>m`XTq  
} 2qEy"DKu  
mbd@4u  
4u;W1=+Vn  
/* w ggl,+7  
**TestMethod.java 'Kq%tM26!  
*/ &^Xm4r%u_  
package NetFox; `fL$t0"  
a]Lr<i8#%  
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public class TestMethod { 2#rF/!`^  
TN0dfba[  
avT>0b:  
public TestMethod() U_!6pqFc  
{ ///xx/weblogic60b2_win.exe {:? -)Xq  
try{ =A,i9Z&  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); _E1:3N|  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 6g!t1%Kb  
SiteFileFetch fileFetch = new SiteFileFetch(bean); #]Cr zLe  
fileFetch.start(); ^v`|0z\  
} +`9T?:fu  
catch(Exception e){e.printStackTrace ();} p_}OtS;  
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} Dl7#h,GTc<  
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public static void main(String[] args) R[9[lQ'vR  
{ Gz kf  
new TestMethod(); z,^baU  
} /|>z7#?m^  
} |i|>-|`!  
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