MyBatis浅尝笔记

MyBatis应属于一种轻量级的java持久层技术，它通过简单的SQL xml或注解，将数据库数据映射到接口与POJO。最近项目要用到mybatis，所以学习之后在这里做个总结，文中的示例以xml配置为主，mybatis也支持注解的方式。

测试数据

先给出demo所使用的表结构，以典型的用户（1）-文章（n）的关系表做demo数据

 1 #
 2 # mysql数据库：数据库名 :dblog
 3 #
 4 
 5 DROP TABLE IF EXISTS m_category;
 6 CREATE TABLE m_category (
 7   id int(11) NOT NULL AUTO_INCREMENT,
 8   name varchar(64) NOT NULL COMMENT '分类名称',
 9   parent_id INT NOT NULL ,
10   level INT NOT NULL DEFAULT 0,
11   path VARCHAR(64) NOT NULL COMMENT '栏目路径，rootId-xxId-xxId',
12   PRIMARY KEY (id)
13 ) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8;
14 
15 DROP TABLE IF EXISTS m_post;
16 CREATE TABLE m_post (
17   id int(11) NOT NULL AUTO_INCREMENT,
18   category_id INT NOT NULL ,
19   user_id INT NOT NULL ,
20   title varchar(64) NOT NULL COMMENT '标题',
21   content text COMMENT '正文',
22   created_at timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP,
23   updated_at timestamp NOT NULL DEFAULT '0000-00-00 00:00:00',
24   PRIMARY KEY (id)
25 ) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8;
26 
27 DROP TABLE IF EXISTS m_user;
28 CREATE TABLE m_user (
29   id int(11) NOT NULL AUTO_INCREMENT,
30   username varchar(64) NOT NULL,
31   password varchar(255) NOT NULL,
32   salt VARCHAR(32) NOT NULL ,
33   avatar varchar(64) DEFAULT NULL,
34   type enum('customer','admin','root') NOT NULL DEFAULT 'customer',
35   remember_token varchar(128) DEFAULT NULL,
36   PRIMARY KEY (id)
37 ) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8;
38 
39 INSERT INTO m_user(id,username, password, salt,type)
40     VALUE (1,'lvyahui','XXXXXXX','abcs','admin');
41 
42 DROP TABLE IF EXISTS m_post_comment;
43 CREATE TABLE m_post_comment(
44   id int(11) AUTO_INCREMENT PRIMARY KEY ,
45   post_id INT NOT NULL ,
46   user_id INT NOT NULL ,
47   content VARCHAR(512) NOT NULL DEFAULT '',
48   created_at TIMESTAMP NOT NULL DEFAULT current_timestamp,
49   updated_at TIMESTAMP NOT NULL DEFAULT '0000-00-00 00:00:00'
50 ) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8;

对应的实体类

Post

 1 package org.lyh.java.mybatis.model;
 2 
 3 import java.sql.Timestamp;
 4 
 5 /**
 6  * @author lvyahui (lvyahui8@gmail.com,lvyahui8@126.com)
 7  * @since 2017/1/1 14:00
 8  */
 9 @SuppressWarnings("unused")
10 public class Post extends BaseModel {
11 
12     private String title;
13     private String content;
14     private Timestamp createdAt;
15     private Timestamp updatedAt;
16 
17     private Integer userId;
18     private Integer categoryId;
19 
20     private User user;
21     private Category category;
22 
23     public String getTitle() {
24         return title;
25     }
26 
27     public void setTitle(String title) {
28         this.title = title;
29     }
30 
31     public String getContent() {
32         return content;
33     }
34 
35     public void setContent(String content) {
36         this.content = content;
37     }
38 
39     public Timestamp getCreatedAt() {
40         return createdAt;
41     }
42 
43     public void setCreatedAt(Timestamp createdAt) {
44         this.createdAt = createdAt;
45     }
46 
47     public Timestamp getUpdatedAt() {
48         return updatedAt;
49     }
50 
51     public void setUpdatedAt(Timestamp updatedAt) {
52         this.updatedAt = updatedAt;
53     }
54 
55     public Integer getUserId() {
56         return userId;
57     }
58 
59     public void setUserId(Integer userId) {
60         this.userId = userId;
61     }
62 
63     public Integer getCategoryId() {
64         return categoryId;
65     }
66 
67     public void setCategoryId(Integer categoryId) {
68         this.categoryId = categoryId;
69     }
70 
71     public User getUser() {
72         return user;
73     }
74 
75     public void setUser(User user) {
76         this.user = user;
77     }
78 
79     public Category getCategory() {
80         return category;
81     }
82 
83     public void setCategory(Category category) {
84         this.category = category;
85     }
86 
87 
88     @Override
89     public String toString() {
90         return "Post{" +
91                 "title='" + title + '\'' +
92                 ", content='" + content + '\'' +
93                 ", createdAt=" + createdAt +
94                 ", updatedAt=" + updatedAt +
95                 ", userId=" + userId +
96                 ", categoryId=" + categoryId +
97                 '}';
98     }
99 }

lvyahui