使用PreparedStatement进行数据库查询

例：模糊查询

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
public class PreparedStatementDemo{
	//MySQL数据库驱动
	public static final String DBDRIVER="com.mysql.cj.jdbc.Driver";
	//MySQL数据库的连接地址
	public static final String DBURL="jdbc:mysql://localhost:3306/mldn?useSSL=false&serverTimezone=UTC";
	//MySQL数据库的连接用户名
	public static final String DBUSER="root";
	//MySQL数据库的连接密码
	public static final String DBPASS="root";

	public static void main(String[] args) throws Exception{
		//加载数据库驱动
		Class.forName(DBDRIVER);
		//获取数据库连接
		Connection conn=DriverManager.getConnection(DBURL,DBUSER,DBPASS);
		//实例化PreparedStatement对象
		String sql="SELECT id,name,password,age,sex,birthday FROM user WHERE name LIKE ? OR password LIKE ? OR sex LIKE ?";
		PreparedStatement pstmt=conn.prepareStatement(sql);
		String keyWord="java";
		pstmt.setString(1,"%"+keyWord+"%");
		pstmt.setString(2,"%"+keyWord+"%");
		pstmt.setString(3,"%"+keyWord+"%");
		//执行查询操作，并输出数据
		ResultSet rs=pstmt.executeQuery();
		while(rs.next()){
			int id=rs.getInt("id");
			String name=rs.getString("name");
			String password=rs.getString("password");
			int age=rs.getInt("age");
			String sex=rs.getString("sex");
			java.util.Date birthday=rs.getDate("birthday");
			System.out.print("编号："+id+";");
			System.out.print("姓名："+name+";");
			System.out.print("密码："+password+";");
			System.out.print("年龄："+age+";");
			System.out.print("性别："+sex+";");
			System.out.println("生日："+birthday);
		}
		//关闭数据库连接
		rs.close();
		pstmt.close();
		conn.close();
	}
}