dbconnection.java

smpp java实现

package projectsmpp;

import java.util.*;
import java.sql.*;
import java.io.*;

public class Dbconnection {
  private Connection conn = null;
  private Statement stmt = null;
  private ResultSet rset = null;
  private static Dbconnection instance = null;
  public Dbconnection() {}

  public static synchronized Dbconnection getInstance() {
    if (instance == null) {
      instance = new Dbconnection();
    }
    return instance;
  }

  public Connection getConnection() {

    try {
      Class.forName("org.gjt.mm.mysql.Driver").newInstance();
    }
    catch (ClassNotFoundException e) {
      e.printStackTrace();
      return null;
    }
    catch (InstantiationException ie) {
      ie.printStackTrace();
      return null;
    }
    catch (IllegalAccessException ae) {
      ae.printStackTrace();
      return null;
    }
    try {
      String connectionString =
          "jdbc:mysql://localhost/jshdsmsw?useUnicode=true&characterEncoding=gb2312";
      this.conn = DriverManager.getConnection(connectionString);
    }
    catch (SQLException e) {
      e.printStackTrace();
      return null;
    }
    return conn;
  }

  public ResultSet executeQuery(String query) throws SQLException {
    this.stmt = conn.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,
                                     ResultSet.CONCUR_READ_ONLY);
    this.rset = stmt.executeQuery(query);
    return rset;
  }

  public void executeUpdate(String query) throws SQLException {
    this.stmt = conn.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,
                                     ResultSet.CONCUR_READ_ONLY);
    stmt.executeUpdate(query);
    if (stmt != null) {
      stmt.close();
    }
  }

  public void close() throws SQLException {
    if (conn != null) {
      conn.close();
    }
    if (rset != null) {
      rset.close();
    }
    if (stmt != null) {
      stmt.close();
    }
  }

  public void finalize() throws Throwable {
    this.close();
  }

}