使用statement和preparedStatement执行sql语句的代码示例

以下是使用Statement和PreparedStatement执行SQL语句的代码示例：

1. 使用Statement执行SQL语句[^1]：

import java.sql.*;

public class StatementExample {
    public static void main(String[] args) {
        try {
            // 建立数据库连接
            Connection conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/mydatabase", "username", "password");
            
            // 创建Statement对象
            Statement stmt = conn.createStatement();            
            // 执行SQL查询语句
            String sql = "SELECT * FROM mytable";
            ResultSet rs = stmt.executeQuery(sql);
            
            // 处理查询结果
            while (rs.next()) {
                int id = rs.getInt("id");
                String name = rs.getString("name");
                System.out.println("ID: " + id + ", Name: " + name);
            }
            
            // 关闭连接
            rs.close();
            stmt.close();
            conn.close();
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
}

2. 使用PreparedStatement执行SQL语句[^2]：

import java.sql.*;

public class PreparedStatementExample {
    public static void main(String[] args) {
        try {
            // 建立数据库连接
            Connection conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/mydatabase", "username", "password");
            
            // 创建PreparedStatement对象
            String sql = "SELECT * FROM mytable WHERE id = ?";
            PreparedStatement pstmt = conn.prepareStatement(sql);
            
            // 设置参数
            pstmt.setInt(1, 1);
            
            // 执行查询
            ResultSet rs = pstmt.executeQuery();
            
            // 处理查询结果
            while (rs.next()) {
                int id = rs.getInt("id");
                String name = rs.getString("name");
                System.out.println("ID: " + id + ", Name: " + name);
            }
            
            // 关闭连接
            rs.close();
            pstmt.close();
            conn.close();
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
}