JDBC

1.加载驱动

优先做，只做一次，用静态代码块

static String driver="com.mysql.cj.jdbc.Driver";
//或者 com.mysql.jdbc.Driver（低版本使用5.7.36以下）
//因为driver是动态的，放在静态代码块里需要将driver定义成静态；
static{
    try {
        Class.forName(driver);
    } catch (ClassNotFoundException e) {
        e.printStackTrace();
    }
}

2.获取数据库连接

优质url："jdbc:mysql://127.0.0.1:3306/cloudwise?useUnicode=true&characterEncoding=utf-8&useSSL=false"

static String url="jdbc:mysql://127.0.0.1:3306/cloudwisetest?useUnicode=true&characterEncoding=utf-8&useSSL=false";
    static String user="root";
    static String password="root";

public static Connection getConnection(){
        Connection connection=null;
        try {
          connection=DriverManager.getConnection(url,user,password);
        } catch (SQLException e) {
            e.printStackTrace();
        }
        System.out.println("数据库连接成功");
        System.out.println(connection.toString());
        return  connection;
    }

3.获取预处理语句对象并执行

 public Boolean executeUpdate(String sql){
        //获取数据库连接
        Connection connection=getConnection();
        //获取预处理语句对象
        PreparedStatement ps=null;
        try {
            ps = connection.prepareStatement(sql);
            int i= ps.executeUpdate();//返回的受影响的行数
            if(i>0){
                System.out.println("操作成功");
                return true;
            }
        } catch (SQLException e) {
            e.printStackTrace();
            System.out.println("操作失败");
        }
        return false;

    }
//测试
String sql="insert into phantomread values(20,20)";
jdbc.executeUpdate(sql1);

有主键自增时，添加时 增加列名，不带自增项

insert into phantomread dept(name,address)values('张三','郑州')

四大金刚

static String driver = "com.mysql.jdbc.Driver";
static String url = "jdbc:mysql://127.0.0.1:3306/db_cloudwise_5?useUnicode=true&characterEncoding=utf-8&useSSL=false&serverTimezone=Asia/Shanghai";
static String username = "root";
static String password = "root";