http断点续传简单实现（java)

/* YoE3<[KD(  
**SiteFileFetch.java U<-D(J
  
*/ L8n|m!MOD  
package NetFox; qY#6SO`_iy  
import java.io.*; ~_a-E  
import java.net.*; 4/)k)gLI  
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public class SiteFileFetch extends Thread { {^\r`Vp  
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SiteInfoBean siteInfoBean = null; //文件信息Bean h.fq,em+H  
long[] nStartPos; //开始位置 :i7;w%
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long[] nEndPos; //结束位置 =qIyqbXz  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 )_NO4`ejs/  
long nFileLength; //文件长度 Q7A MRrN  
boolean bFirst = true; //是否第一次取文件 |D
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boolean bStop = false; //停止标志 ;=UsAB]  
File tmpFile; //文件下载的临时信息 &-
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DataOutputStream output; //输出到文件的输出流 u-C)v*#L  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） L.WljNo  
public SiteFileFetch(SiteInfoBean bean) throws IOException 39jG8zr=Z[  
{ TB^$1C  
siteInfoBean = bean; w*MpX U<  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); wdZ/Xp9]  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); #89!'W  
if(tmpFile.exists ()) =rK+eG#,  
{ ?'je)
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bFirst = false; 8.~kK<)!  
read_nPos(); yOKI*.}  
} abEmRJTmW  
else -!9G0h&i|  
{  Mc}^LDX  
nStartPos = new long[bean.getNSplitter()]; bJ;'`sw1  
nEndPos = new long[bean.getNSplitter()]; llsfTrp  
} *\q d  
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} 3yXY.>'  
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public void run() s|ITsz0,td  
{ b_):MQ1
{  
//获得文件长度 xP,hTE  
//分割文件 YgoBHE0#  
//实例FileSplitterFetch FsryEHz  
//启动FileSplitterFetch线程 n-OL0$Xu  
//等待子线程返回 "g#i'"qnW  
try{ k;L6R!V  
if(bFirst) D#)b+7N-  
{
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nFileLength = getFileSize(); d^6M9lGU  
if(nFileLength == -1) MqUH',\3  
{ 1!gbTeVlY  
System.err.println("File Length is not known!"); '`<w#z}AF  
} !v0LBe4  
else if(nFileLength == -2) >dG[G>  
{ N
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System.err.println("File is not access!"); 6MkP |vr6  
} w+{LAS  
else
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{ O0y_Lm\  
for(int i=0;i<nStartPos.length;i++) veh<R]U  
{ m9Hit8f@Q  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); *D3/@S$B  
} tNX|U:Y*  
for(int i=0;i<nEndPos.length-1;i++) >e"#'K0?\  
{ n.G!43@*N  
nEndPos = nStartPos[i+1]; :08,JL{  
} ?S$P
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nEndPos[nEndPos.length-1] = nFileLength; xF44M]i  
} 8ITdS
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} '6Q=#:mc\  
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//启动子线程 fwf$Co+R:*  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; $p?aVO  
for(int i=0;i<nStartPos.length;i++) %|i`kYsy  
{ ^ovR7+V  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Y.r+wc]  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), `$C n~dT  
nStartPos,nEndPos,i); 8pgEix/M5o  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 'X2POay1  
fileSplitterFetch.start(); (*)hD(C5  
} ox (%5c)b|  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), d;}nh2*  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); {jX2}  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Per1
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nEndPos = " + nFileLength); >J>[& zS  
// fileSplitterFetch[nPos.length-1].start(); %-0t?/>  
;BIY^6,7e  
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//等待子线程结束 )TH@#1  
//int count = 0; 0=E]cQwh  
//是否结束while循环 0s2v'A[\  
boolean breakWhile = false; `^Em&6!!  
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while(!bStop) 'CkIz"Wd  
{ H}bJ"(9$vC  
write_nPos(); v-_e)m^  
Utility.sleep(500); vOpKNp  
breakWhile = true; -pXSSa;O9  
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for(int i=0;i<nStartPos.length;i++) e&aWq@D  
{ r? E)obE  
if(!fileSplitterFetch.bDownOver) Da&]y
 
{ 8q}q{8  
breakWhile = false; V /V9B2.$  
break; UQ@L V~6{R  
} 7Da`   
} h{HHLR  
if(breakWhile) k{SAvKx=  
break; d,n 'n  
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//count++; >e[i5  
//if(count>4) (jl D+Y_  
// siteStop(); <;Zmjeb+#  
} cP_.&!T  
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System.err.println("文件下载结束！"); 8&`LYdzt  
} J,y[[CdH`  
catch(Exception e){e.printStackTrace ();} =.]4;z  
} SmSH2m-  
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//获得文件长度 <+vw@M  
public long getFileSize() +Kbjzh3<wG  
{ iVq'r4S  
int nFileLength = -1; 9H`XeQ.  
try{ |_aa&v~  
URL url = new URL(siteInfoBean.getSSiteURL()); GH:jH]u!V  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); {go;C}  
httpConnection.setRequestProperty("User-Agent","NetFox"); '^~{@~ ;%L  
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int responseCode=httpConnection.getResponseCode(); MJ [m  
if(responseCode>=400) Fgh_9S9J  
{ A1>OY^p3%  
processErrorCode(responseCode); 
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return -2; //-2 represent access is error *@=/qkaJaI  
} ~^fZx5  
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String sHeader; zFff`]^`  
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for(int i=1;;i++) 62o:,IcoG  
{ .Una+Z  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 3E
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//Utility.log(in.readLine()); Q%tXQP.r  
sHeader=httpConnection.getHeaderFieldKey(i); W^LY'ypT  
if(sHeader!=null) ex (.=X 1  
{ ""F5z,'  
if(sHeader.equals("Content-Length")) f=gW]x7'R+  
{ .p]RKS=(:  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); k(7&N0V%zz  
break; iYm-tsER;  
} ']z{{UNUN  
} YdC6k?tzS  
else Nk VK  
break; /,&<6c-Q@W  
} [<6^qla  
} FX`>J6l:X  
catch(IOException e){e.printStackTrace ();} 1.{z3_S21:  
catch(Exception e){e.printStackTrace ();} H-*yh!  
*>'V1b4}  
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Utility.log(nFileLength); <~'"<HwtK  
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return nFileLength; dx{bB%?Y\=  
} u^bidd6JRn  
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//保存下载信息（文件指针位置） sn$9Shgh  
private void write_nPos() YPK(be_|I  
{ pF:$  ko  
try{ 9gEw
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output = new DataOutputStream(new FileOutputStream(tmpFile)); C>j@,G4  
output.writeInt(nStartPos.length); ]kRfB:4ED  
for(int i=0;i<nStartPos.length;i++) _] sn0rX  
{ 1AfnzGvA  
// output.writeLong(nPos); lC("y' ::  
output.writeLong(fileSplitterFetch.nStartPos); a85$K$b>  
output.writeLong(fileSplitterFetch.nEndPos); `nv~NLkl  
} "
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output.close(); \lf;P?M^  
} #9}D4i.`}  
catch(IOException e){e.printStackTrace ();} m^f0V2M_  
catch(Exception e){e.printStackTrace ();} (%e.:W${  
} 2%@4]  
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//读取保存的下载信息（文件指针位置） `maKN\;  
private void read_nPos() ,+vy,<e&  
{ R_ ,UMt  
try{ Ug t.&IA  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); K'Tm_"[u  
int nCount = input.readInt(); kmsb hYM)  
nStartPos = new long[nCount]; I{9QeRI  
nEndPos = new long[nCount]; &5spTMw8  
for(int i=0;i<nStartPos.length;i++) O-~7b(Z  
{ AJ?r,!)  
nStartPos = input.readLong(); 6YLj^w] %  
nEndPos = input.readLong(); )72+\C[*~r  
} YY((V@|K  
input.close(); nE&@Q  
} 1s2>C!\  
catch(IOException e){e.printStackTrace ();} EQyC1j  
catch(Exception e){e.printStackTrace ();} LX
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} T/Gz94c  
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private void processErrorCode(int nErrorCode) ~u!|qM  
{
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System.err.println("Error Code : " + nErrorCode); _8riUt  
} F2dHH^  
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//停止文件下载 U;V7 u/{  
public void siteStop() lL3khJ:%  
{ uK#4(eY=W  
bStop = true; dTC7Fm  
for(int i=0;i<nStartPos.length;i++) Y. 5_6'Eo?  
fileSplitterFetch.splitterStop(); gsvuE  
" 4K(jXq|  
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} 5k3n\sqZA  
} <fjX[l<Uz  
//负责部分文件的抓取 {3p4:*}  
**FileSplitterFetch.java Av$^  
*/ F/bT)QT<f  
package NetFox; ?m=N]!n  
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import java.io.*; k\YG^I  
import java.net.*; a|x.C6Pe  
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public class FileSplitterFetch extends Thread { MS>Ge0P("~  
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String sURL; //File URL V>%rv'G8  
long nStartPos; //File Snippet Start Position Ic:(Gi- %  
long nEndPos; //File Snippet End Position dvx#q5f_S  
int nThreadID; //Thread's ID el<s8:lA  
boolean bDownOver = false; //Downing is over WZejp}x  
boolean bStop = false; //Stop identical gJXq^~-hd  
FileAccessI fileAccessI = null; //File Access interface 9ni1f{k  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException E7Ul;d  
{ '&R2U_  
this.sURL = sURL; dulI&_x  
this.nStartPos = nStart; s1$nvTzBr  
this.nEndPos = nEnd; u+e{Mim  
nThreadID = id; Z{Qu<vy_  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Y3cMC)  
} hh)`645=x  
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public void run() (KD RkE|=  
{ &yTqZ*Yuk  
while(nStartPos < nEndPos && !bStop) p* (JjH  
{ 9y8&9<#  
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try{ Mj?`j_X  
URL url = new URL(sURL); A5RN5`}  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ]G=L=D^cK  
httpConnection.setRequestProperty("User-Agent","NetFox"); W$;,CU.v  
String sProperty = "bytes="+nStartPos+"-"; J+DDh=%  
httpConnection.setRequestProperty("RANGE",sProperty); V`d,qn)i  
Utility.log(sProperty); Bz-c$me1  
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InputStream input = httpConnection.getInputStream(); ~'H]jN  
//logResponseHead(httpConnection); n;C :0  
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byte[] b = new byte[1024]; 82qoGSD.  
int nRead; YnS#H"  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) wn, KY$/  
{ @#>rYAb8,  
nStartPos += fileAccessI.write(b,0,nRead); YQ)kRhFA  
//if(nThreadID == 1) c(m<h+2VL  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 1 ~*7f>  
} ]BZA:dd.G  
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Utility.log("Thread " + nThreadID + " is over!"); 0c]/bs{}  
bDownOver = true; N7QK> "a  
//nPos = fileAccessI.write (b,0,nRead); ,vawzq[oSy  
} "'.UU$]d  
catch(Exception e){e.printStackTrace ();} Z'W=\rl  
} "1*:JVG  
} o]_dJB  
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//打印回应的头信息 $am$EU?s  
public void logResponseHead(HttpURLConnection con) Xp% v.M  
{ wqs?828x  
for(int i=1;;i++) Hqx-~hQO  
{ mzKiO_g}  
String header=con.getHeaderFieldKey(i); hJ? O],4J  
if(header!=null) 
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//responseHeaders.put(header,httpConnection.getHeaderField(header)); uEP*iPLD@  
Utility.log(header+" : "+con.getHeaderField(header)); "ycJ:Xv49  
else 2r4Uh1D~  
break; 6=/F$|  
} mb3"U"ohs  
} |4zIfAO  
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public void splitterStop() jo@6?( *4  
{ F6|]4H.3Q  
bStop = true; 1D7`YKI9h  
} [Ek7b*  
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} LEf^cM=>  
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/* 2(+
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**FileAccess.java q`a'gJx#y  
*//文件访问(定位，写) 1#2 I  
package NetFox; MUc$j&  
import java.io.*; @ioJ]$o7  
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public class FileAccessI implements Serializable{ lU\[aNs  
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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 ^|(LAjet  
RandomAccessFile oSavedFile; 5d^sA;c  
long nPos; 5m 4P\y^a  
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public FileAccessI() throws IOException
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{ 7U"g3a)=  
this("",0); 2- h{N  
} q:0N<$63  
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>\#*P'y`d  
public FileAccessI(String sName,long nPos) throws IOException Eyqa?$R  
{ @n /nH?L  
oSavedFile = new RandomAccessFile(sName,"rw"); 'sKk"bi;0  
this.nPos = nPos; $( kF#  
oSavedFile.seek(nPos); "|q&ea rc  
} #q$HQ&k  
()?(I?I
I  
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public synchronized int write(byte[] b,int nStart,int nLen) v{N`.~,^  
{ u4?L 67x  
int n = -1; 2MIi=c:oqK  
try{ ^ VyKd  
oSavedFile.write(b,nStart,nLen); ,R\ \%  
n = nLen; 3(N$nsi  
} cwlRQzQ(  
catch(IOException e)  4e7-0}0  
{ Iyn(?w  
e.printStackTrace (); #gN&lY:CFn  
} bsli0FJSh'  
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return n; Qd{CMmx  
} ;ef}}K  
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} ec;o\erPG  
}R2u@%n{  
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/* ^uc=f2=>,  
**SiteInfoBean.java Ge@{_  
*/ `
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package NetFox; %aCqi(.7  
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public class SiteInfoBean { _4~+{l+  
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private String sSiteURL; //Site's URL +\]\[6  
private String sFilePath; //Saved File's Path  8dA~\a  
private String sFileName; //Saved File's Name #zs~," dRv  
private int nSplitter; //Count of Splited Downloading File T?
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public SiteInfoBean() F/{!tx  
{//nSplitter的缺省值为5 T'9'G M  
//default value of nSplitter is 5 Sz`,X0a  
this("","","",5); RtS+<^2a;  
} ? OM!+O  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) PC8Q"O  
{  <kqo^  
sSiteURL= sURL; hn@08t G  
sFilePath = sPath; cV6D<,)  
sFileName = sName; KV *#T20T  
this.nSplitter = nSpiltter; JH9J5%sp  
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} CAhXQ7w'Z  
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public String getSSiteURL() W{+2/P
 
{ 3nQ`]5.Q w  
return sSiteURL; #c!lS<z  
} Ld~/u]K%V  
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;  
public void setSSiteURL(String value) TD0 B%  
{ Wac&b  
sSiteURL = value; J*M>6Q.)  
} %tGO?JMkd  
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public String getSFilePath() Ti5-6%~&  
{ r,p%U!S<hV  
return sFilePath; ZY+qA  
} 6cX
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public void setSFilePath(String value) 4D4j7  
{ Y:[u1~a  
sFilePath = value; u*`GiZAO  
} 8lrpve  
#X1
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public String getSFileName() TvbE2Q;/UL  
{ /J;Kn]5e  
return sFileName; GD$l||8  
} )y$(AJx$  
#"~<HG}bR/  
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public void setSFileName(String value) ~c `l@:  
{ 57c8xk[.2  
sFileName = value;
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} =7eV/3  
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public int getNSplitter() f-Z/tfC  
{ 26h21Z16q  
return nSplitter; eSq.GtI  
} b\2 ds,  
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public void setNSplitter(int nCount) j#ab_3xH  
{ G 3ptx! D  
nSplitter = nCount; Dlvz)  
} ;4\;mmLVk  
} &6VnySE?  
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.  
/* wibNQ`4k  
**Utility.java cvL;3jRo  
*/ s~X%Y<9l  
package NetFox; =I_'
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public class Utility { 9->if/r,o  
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public Utility() H Pz+Dm  
{ ~P-mC@C  
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} G3T]`Atf  
/)O"l@ }U  
//线程睡眠 ~k5W@`"W  
public static void sleep(int nSecond) JxU5 fe  
{ z F;K  
try{ Q"#J6@  
Thread.sleep(nSecond); fk-RV>yr  
} 4*;MJ[|  
catch(Exception e) K|=A:  
{ I&5!=kR  
e.printStackTrace (); m1AJ{cs  
} {)<v
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} Ow,b^|  
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//日志 Aos+dP5h,8  
public static void log(String sMsg) #/37V2E  
{ $*m-R*kt  
System.err.println(sMsg); YS_;OFsd  
} ^iYj[~  
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public static void log(int sMsg) U6s[`H3I{  
{ f|(M.U-  
System.err.println(sMsg); xT2PyI_:  
} 9>#6*/Oa7  
} K*dCc}:`  
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/*  %;!.n{X  
**TestMethod.java qqU 64E  
*/ hi[pVk~B)  
package NetFox; 5!9zI+S|=`  
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c&Q$L }  
public class TestMethod { /Z4et'Lo  
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public TestMethod() TD_Oo-+\  
{ ///xx/weblogic60b2_win.exe *Pg2c(Vg  
try{ Etm?'  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); w4Z'K&d=  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); f
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SiteFileFetch fileFetch = new SiteFileFetch(bean); poFg1  
fileFetch.start(); i@J;G`  
}  9gZ$
 
catch(Exception e){e.printStackTrace ();} P!k{u^$L  
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} >(RkZ}z  
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public static void main(String[] args) xkAK!uVy  
{ bZV
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new TestMethod(); jz0T_\8D`  
} 3;Fhg!ZO  
} vvOV2n.WD  
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