對(duì)SQL進(jìn)行預(yù)處理可以使用通配符“？”來代替任何的字段值
然后通過setxxx()方法為SQL語句中的參數(shù)賦值

功能：使用預(yù)處理語句實(shí)現(xiàn)對(duì)數(shù)據(jù)庫(kù)tysql中stu表的id=2的查詢和輸出
代碼：

import java.sql.*;
public class Prep {
    static Connection con;
    static PreparedStatement sql;
    static ResultSet res;
    
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Prep c = new Prep();
        con = c.getConnection();
        try{
            sql = con.prepareStatement("select * from stu where id =?");//預(yù)處理語句
            sql.setInt(1,2);
            res = sql.executeQuery();
            while(res.next()){
                String id = res.getString(1);
                String name = res.getString("name");
                String sex = res.getString("sex");
                String birthday = res.getString("birthday");
                System.out.println("編號(hào)："+id);
                System.out.println("姓名："+name);
                System.out.println("性別："+sex);
                System.out.println("生日："+birthday);
            }
        }catch(Exception e){
            e.printStackTrace();
        }
    }
    
    public Connection getConnection(){
        try{
            Class.forName("com.mysql.jdbc.Driver");
            con = DriverManager.getConnection("jdbc:mysql:"+"http://localhost/tysql?useSSL=false","root","12345678");
        }catch(Exception e){
            e.printStackTrace();
        }
        return con;
    }

}

結(jié)果：
MYSQL:

image.png

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