Пытаюсь создать pool-соединение проекта.
Созданию pool соединение используя класс AbstractDao и ServletContextListener.
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package db;
import javax.sql.DataSource;
public abstract class AbstractDao {
protected final DataSource datasource;
public AbstractDao() {
datasource = DatasourceConnection.getDataSource();
}
}
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package db;
import javax.naming.Context;
import javax.naming.InitialContext;
import javax.naming.NamingException;
import javax.servlet.http.HttpSessionListener;
import javax.servlet.ServletContext;
import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;
import javax.sql.DataSource;
public class DatasourceConnection implements ServletContextListener {
private ServletContext ctx;
private static DataSource datasource;
public void contextDestroyed(ServletContextEvent event) {
// TODO Auto-generated method stub
}
public void contextInitialized(ServletContextEvent event) {
Context initCtx = null;
Context envCtx = null;
ctx = event.getServletContext();
try {
initCtx = new InitialContext();
envCtx = (Context) initCtx.lookup("java:comp/env");
datasource = (DataSource) envCtx.lookup("jdbc/mysql");
ctx.setAttribute("DBCPool", datasource);
} catch (NamingException e) {
e.printStackTrace();
}
}
}
web.xml
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<listener>
<listener-class>db.DatasourceConnection</listener-class>
</listener>
И сервлет, от которого наследуются все остальные
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package db;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.sql.DataSource;
public class init extends HttpServlet {
public DataSource datasource = null;
@Override
public void init() throws ServletException {
datasource = (DataSource) getServletContext().getAttribute("DBCPool");
}
}
Вопрос в том, как сделать в сервлете с рекурсией одно соединение на весь сервлет. Пытаюсь вот так и ничего не получается.
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package calc;
import java.io.IOException;
import java.io.PrintWriter;
import java.math.BigDecimal;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class cost1 extends db.init {
Connection conn = null;
public void init() throws ServletException {
try {
conn = datasource.getConnection();
} catch (SQLException ex) {
Logger.getLogger(costp1.class.getName()).log(Level.SEVERE, null, ex);
}
}
public void close() {
if (conn != null) {
try {
conn.close();
} catch (SQLException ex) {
Logger.getLogger(costp1.class.getName()).log(Level.SEVERE, null, ex);
}
}
}
protected void processRequest(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html;charset=UTF-8");
PrintWriter out = response.getWriter();
try {
Cost2(1, BigDecimal.ONE);
} finally {
out.close();
}
}
public BigDecimal Cost2(Integer product_id, BigDecimal k) {
PreparedStatement ps = null;
ResultSet rset = null;
BigDecimal cost = BigDecimal.ZERO;
String query;
BigDecimal summa1 = null;
try {
if (k.compareTo(new BigDecimal("1e-3")) < 0) {
cost = BigDecimal.ZERO;
} else {
query = "select .......l";
ps = conn.prepareStatement(query);
cost = BigDecimal.ZERO;
while (rset.next()) {
if (rset.getString("param").equals("0")) {
summa1 = rset.getBigDecimal("sum");
} else {
summa1 = rset.getBigDecimal("coef").multiply(Cost2(product_id, k.multiply(rset.getBigDecimal("coef"))));
}
cost = cost.add(summa1.setScale(2, BigDecimal.ROUND_HALF_UP));
}
}
} catch (SQLException ex) {
Logger.getLogger(costp.class.getName()).log(Level.SEVERE, null, ex);
} finally {
try {
if (rset != null) {
rset.close();
}
if (ps != null) {
ps.close();
}
} catch (SQLException ex) {
Logger.getLogger(costp.class.getName()).log(Level.SEVERE, null, ex);
}
return cost.setScale(2, BigDecimal.ROUND_HALF_UP);
}
}
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
processRequest(request, response);
}
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
processRequest(request, response);
}
}
