前言
MyBatis 是一款优秀的持久层框架,它支持定制化 SQL、存储过程以及高级映射。MyBatis 避免了几乎所有的 JDBC 代码和手动设置参数以及获取结果集。MyBatis 可以使用简单的XML或注解来配置和映射原生类型、接口和 Java 的 POJO(Plain Old Java Objects,普通老式 Java 对象)为数据库中的记录。
一、建库建表
- 建库
CREATE DATABASE test;
- 建表
CREATE TABLE `users` (
`id` bigint(20) NOT NULL AUTO_INCREMENT COMMENT '主键id',
`userName` varchar(32) DEFAULT NULL COMMENT '用户名',
`passWord` varchar(32) DEFAULT NULL COMMENT '密码',
`user_sex` varchar(32) DEFAULT NULL,
`nick_name` varchar(32) DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=32 DEFAULT CHARSET=utf8;
二、pom.xml文件
添加MyBatis依赖和MySQL依赖.
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.1.7.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<groupId>com.huzh</groupId>
<artifactId>springboot-mybatis</artifactId>
<version>1.0-SNAPSHOT</version>
<name>springboot-mybatis</name>
<description>springboot-mybatis</description>
<properties>
<java.version>1.8</java.version>
<mybatis.version>2.1.0</mybatis.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-jdbc</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<!--mybatis-->
<dependency>
<groupId>org.mybatis.spring.boot</groupId>
<artifactId>mybatis-spring-boot-starter</artifactId>
<version>${mybatis.version}</version>
</dependency>
<!--mysql-->
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<scope>runtime</scope>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-devtools</artifactId>
<scope>runtime</scope>
<optional>true</optional>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
三、实体类
- 实体类
public class User implements Serializable {
private static final long serialVersionUID = 1L;
private Long id;
private String userName;
private String passWord;
private UserSexEnum userSex;
private String nickName;
public User() {
super();
}
public User(String userName, String passWord, UserSexEnum userSex) {
super();
this.passWord = passWord;
this.userName = userName;
this.userSex = userSex;
}
public Long getId() {
return id;
}
public void setId(Long id) {
this.id = id;
}
public String getUserName() {
return userName;
}
public void setUserName(String userName) {
this.userName = userName;
}
public String getPassWord() {
return passWord;
}
public void setPassWord(String passWord) {
this.passWord = passWord;
}
public UserSexEnum getUserSex() {
return userSex;
}
public void setUserSex(UserSexEnum userSex) {
this.userSex = userSex;
}
public String getNickName() {
return nickName;
}
public void setNickName(String nickName) {
this.nickName = nickName;
}
@Override
public String toString() {
// TODO Auto-generated method stub
return "userName " + this.userName + ", pasword " + this.passWord + "sex " + userSex.name();
}
}
- 枚举类
public enum UserSexEnum {
MAN, WOMAN
}
四、两种整合模式
- 注解模式
1、配置mybatis和数据库
spring:
datasource:
driver-class-name: com.mysql.jdbc.Driver
username: root
password: 123456
url: jdbc:mysql://localhost:3306/test?serverTimezone=GMT
mybatis:
#这个配置用来指定bean在哪个包里,避免存在同名class时找不到bean
type-aliases-package: com.huzh.springbootmybatisannotation.model
2、编写 Mapper 层
public interface UserMapper {
@Select("SELECT * FROM users")
@Results({
@Result(property = "userSex", column = "user_sex", javaType = UserSexEnum.class),
@Result(property = "nickName", column = "nick_name")
})
List<User> getAll();
@Select("SELECT * FROM users WHERE id = #{id}")
@Results({
@Result(property = "userSex", column = "user_sex", javaType = UserSexEnum.class),
@Result(property = "nickName", column = "nick_name")
})
User getOne(Long id);
@Insert("INSERT INTO users(userName,passWord,user_sex) VALUES(#{userName}, #{passWord}, #{userSex})")
void insert(User user);
@Update("UPDATE users SET userName=#{userName},nick_name=#{nickName} WHERE id =#{id}")
void update(User user);
@Delete("DELETE FROM users WHERE id =#{id}")
void delete(Long id);
}
3、创建controller
@RestController
public class UserController {
@Autowired
private UserMapper userMapper;
@RequestMapping("/getUsers")
public List<User> getUsers() {
List<User> users=userMapper.getAll();
return users;
}
@RequestMapping("/getUser")
public User getUser(Long id) {
User user=userMapper.getOne(id);
return user;
}
@RequestMapping("/add")
public void save(User user) {
userMapper.insert(user);
}
@RequestMapping(value="update")
public void update(User user) {
userMapper.update(user);
}
@RequestMapping(value="/delete/{id}")
public void delete(@PathVariable("id") Long id) {
userMapper.delete(id);
}
}
- xml模式
1、配置mybatis和数据库
- 指定了 Mybatis 基础配置文件和实体类映射文件的地址。
spring:
datasource:
driver-class-name: com.mysql.jdbc.Driver
username: root
password: 123456
url: jdbc:mysql://localhost:3306/test?serverTimezone=GMT
mybatis:
#这个配置用来指定bean在哪个包里,避免存在同名class时找不到bean
type-aliases-package: com.huzh.springbootmybatisxml.model
##检查 mybatis 配置是否存在,一般命名为 mybatis-config.xml
check-config-location: true
##配置文件位置
config-location: classpath:mybatis/mybatis-config.xml
## dao xml 文件地址
mapper-locations: classpath:mapper/*Mapper.xml
- mybatis-config.xml 配置
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN" "http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
<typeAliases>
<typeAlias alias="Integer" type="java.lang.Integer" />
<typeAlias alias="Long" type="java.lang.Long" />
<typeAlias alias="HashMap" type="java.util.HashMap" />
<typeAlias alias="LinkedHashMap" type="java.util.LinkedHashMap" />
<typeAlias alias="ArrayList" type="java.util.ArrayList" />
<typeAlias alias="LinkedList" type="java.util.LinkedList" />
</typeAliases>
</configuration>
- 添加 User 的映射文件
<?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" >
<mapper namespace="com.huzh.springbootmybatisxml.mapper.UserMapper">
<resultMap id="BaseResultMap" type="com.huzh.springbootmybatisxml.model.User">
<id column="id" property="id" jdbcType="BIGINT"/>
<result column="userName" property="userName" jdbcType="VARCHAR"/>
<result column="passWord" property="passWord" jdbcType="VARCHAR"/>
<result column="user_sex" property="userSex" javaType="com.huzh.springbootmybatisxml.enums.UserSexEnum"/>
<result column="nick_name" property="nickName" jdbcType="VARCHAR"/>
</resultMap>
<parameterMap id="user" type="com.huzh.springbootmybatisxml.model.User"/>
<sql id="Base_Column_List" >
id, userName, passWord, user_sex, nick_name
</sql>
<select id="getAll" resultMap="BaseResultMap" >
SELECT
<include refid="Base_Column_List" />
FROM users
</select>
<select id="getOne" parameterType="java.lang.Long" resultMap="BaseResultMap" >
SELECT
<include refid="Base_Column_List" />
FROM users
WHERE id = #{id}
</select>
<insert id="insert" parameterMap="user" >
INSERT INTO
users
(userName,passWord,user_sex)
VALUES
(#{userName}, #{passWord}, #{userSex})
</insert>
<update id="update" parameterMap="user" >
UPDATE
users
SET
<if test="userName != null">userName = #{userName},</if>
<if test="passWord != null">passWord = #{passWord},</if>
nick_name = #{nickName}
WHERE
id = #{id}
</update>
<delete id="delete" parameterType="java.lang.Long" >
DELETE FROM
users
WHERE
id =#{id}
</delete>
</mapper>
2、编写 Mapper 层
public interface UserMapper {
List<User> getAll();
User getOne(Long id);
void insert(User user);
void update(User user);
void delete(Long id);
}
3、创建controller
@RestController
public class UserController {
@Autowired
private UserMapper userMapper;
@RequestMapping("/getUsers")
public List<User> getUsers() {
List<User> users = userMapper.getAll();
return users;
}
@RequestMapping("/getUser")
public User getUser(Long id) {
User user = userMapper.getOne(id);
return user;
}
@RequestMapping("/add")
public void save(User user) {
userMapper.insert(user);
}
@RequestMapping(value = "update")
public void update(User user) {
userMapper.update(user);
}
@RequestMapping(value = "/delete/{id}")
public void delete(@PathVariable("id") Long id) {
userMapper.delete(id);
}
}
5、启动类
添加对 mapper 包扫描@MapperScan,可以直接在 Mapper 类上面添加注解@Mapper,建议使用下面那种,不然每个 mapper 要加个注解。
@MapperScan("com.huzh.springbootmybatisxml.mapper")
@SpringBootApplication
public class SpringbootMybatisXmlApplication {
public static void main(String[] args) {
SpringApplication.run(SpringbootMybatisXmlApplication.class, args);
}
}
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