Java优学网MyBatis学习步骤教程：从入门到精通，轻松掌握数据库操作

<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"

"http://mybatis.org/dtd/mybatis-3-mapper.dtd">

User user1 = sqlSession.selectOne("findUserById", 1L); User user2 = sqlSession.selectOne("findUserById", 1L); // user2直接从一级缓存返回，不会再次访问数据库

public class User {

private Long id;
private String username;
private String email;
private Date createTime;
private Department department;
private List<Role> roles;
// getter/setter省略

}