JDBC

最新推荐文章于 2022-11-23 21:28:13 发布

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最新推荐文章于 2022-11-23 21:28:13 发布

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分类专栏： Java

本文链接：https://blog.youkuaiyun.com/lan266548_ning/article/details/80644263

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JDBC:java database connectivity,连接数据库

JDBC规范：

1，DriverManager:用于注册驱动

2，Connection:表示与数据库创建的连接

3，Statement:操作数据库sql语句的对象

4，ResultSet：结果集或一张虚拟表

注意：在写Java连接数据库之前必须先导入jar包

这里写图片描述

查询

public class Demo01_select {

    public static void main(String[] args) throws Exception {
        // TODO Auto-generated method stub
        //加载驱动
        Class.forName("com.mysql.jdbc.Driver");
        //获取链接Connection
        Connection conn=DriverManager.getConnection("jdbc:mysql://localhost:3306/mydb", "lml", "123");
        //得到执行sql语句的对象Statement
        Statement stmt=conn.createStatement();
        //执行sql语句，并返回结果
        ResultSet rs=stmt.executeQuery("select * from users");
        while(rs.next()){
            System.out.println(rs.getObject("id"));
            System.out.println(rs.getObject("name"));
            System.out.println(rs.getObject("password"));
        }
        rs.close();
        stmt.close();
        conn.close();
    }

}

更新

public class Demo02_update {

    public static void main(String[] args) throws Exception {
        // TODO Auto-generated method stub
        Class.forName("com.mysql.jdbc.Driver");
        Connection conn=DriverManager.getConnection("jdbc:mysql://localhost:3306/mydb", "lml", "123");
        Statement stmt=conn.createStatement();
        int x=stmt.executeUpdate("update users set id=3,name='cn',password='123' where id=2");
        if(x>0){
            System.out.println("success");
        }

        stmt.close();
        conn.close();
    }

}

删除

public class Demo03_delete {

    public static void main(String[] args) throws Exception {
        // TODO Auto-generated method stub
        Class.forName("com.mysql.jdbc.Driver");
        Connection conn=DriverManager.getConnection("jdbc:mysql://localhost:3306/mydb", "lml", "123");
        Statement stmt=conn.createStatement();
        int x=stmt.executeUpdate("delete from users where id=3");
        if(x>0){
            System.out.println("success");
        }

        stmt.close();
        conn.close();
    }

}

添加

public class Demo04_insert {

    public static void main(String[] args) throws Exception {
        // TODO Auto-generated method stub
        Class.forName("com.mysql.jdbc.Driver");
        Connection conn=DriverManager.getConnection("jdbc:mysql://localhost:3306/mydb", "lml", "123");
        Statement stmt=conn.createStatement();
        int x=stmt.executeUpdate("insert into users values(4,'tom','123456')");
        if(x>0){
            System.out.println("success");
        }

        stmt.close();
        conn.close();
    }

}