使用JavaBean封装数据库操作

package com.javabean;
import java.sql.*;

public class DBOperation {
static final String USER_NAME = "root";
static final String PASSWORD = "leap";
static final String URL = "jdbc:mysql://localhost:3306/votedb?useUnicode=yes&characterEncoding=utf-8";
Connection con = null;
Statement stmt = null;
ResultSet rs = null;

public DBOperation() {
try {
Class.forName("com.mysql.jdbc.Driver");
Connection conn = DriverManager.getConnection(URL, USER_NAME,
PASSWORD);
stmt = conn.createStatement();
} catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (SQLException e) {
e.printStackTrace();
}
}

//执行查询
public ResultSet executeQuery(String sql) {
try {
rs = stmt.executeQuery(sql);

} catch (SQLException ex) {
System.err.println(ex.getMessage());
}
return rs;
}

//执行更新
public int executeUpdate(String sql) {
int result = 0;
try {
result = stmt.executeUpdate(sql);
} catch (SQLException ex) {
ex.getMessage();
}
return result;
}

};

DBOperation dbOperation = new DBOperation();
String sql = "select * from Admin";
ResultSet rs = dbOperation.executeQuery(sql);

<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<%@ page import="java.sql.*"%>
<jsp:useBean id="dbOperation" class="com.javabean.DBOperation" />

<%
String sql = "select * from topic";
ResultSet rs = dbOperation.executeQuery(sql);
%>