使用JDBC实现动态查询

package jdbc;
/*
 * 动态查询
 */
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;


public class Demo1 {
public static void main(String[] args) throws Exception {
	Class.forName("com.mysql.jdbc.Driver");
	Connection con = DriverManager.getConnection("jdbc:mysql://127.0.0.1:3306/usta", "root", "root");
	String sql = "select * from student where id = ?";
	PreparedStatement ps = con.prepareStatement(sql);
	ps.setString(1, "3");
	ResultSet rs = ps.executeQuery();
	while(rs.next()) {
		System.out.println(rs.getInt(1)+" "+rs.getString(2));
	}
}
}