mybatis学习8-CRUD注解方式

前期mysql准备

create database cong
use cong;
create table account(
    id int primary key auto_increment,
    name varchar(40),
    money float
)character set utf8 collate utf8_general_ci;

insert into account(name,money) values('aaa',1000);
insert into account(name,money) values('bbb',1000);
insert into account(name,money) values('ccc',1000);

2.实体类

package com.cong.pojo;

public class Account {
    private int id;
    private String name;
    private float money;
　　 ...
}

查找

    @Select("select * from account")
    List<Account> findAll();//查询所有

    @Select("select * from account where id = #{id}")
    Account findById(int id);//根据id查询

    @Select("select * from account where name like #{name}")
    //@Select("select * from account where name like '%${value}%'")
    List<Account> findByName(String name);//根据名字模糊查询

    @Select("select count(*) from account")
    int findTotal();//查询数量

插入

    @Insert("insert into account(name,money) values(#{name},#{money})")
    int saveAccount(Account account);//返回值是数据库的影响条目

修改

    @Update("update account set name=#{name},money=#{money} where id = #{id}")
    void updateAccount(Account account);//修改

    //修改单个或少量属性，没必要传递一个对象，直接传递属性，通过注解标注
    @Update("update account set name=#{n} where id = #{i}")
    void updateAccountByParam(@Param("n")String name,@Param("i")int id);

删除

    @Delete("delete from account where id = #{id}")
    void deleteAccount(int id);