目录
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信息,将接口和 Java 的 POJOs(Plain Ordinary Java Object,普通的 Java对象)映射成数据库中的记录。
这里,主要先介绍springboot整合Mybatis中使用xml的形式,毕竟xml比较灵活方便,接下来的一篇文章,小编会写关于注解的形式。这里仅做入门学习,mybatis中一对多,一对一,多对多的映射暂时不介绍,介绍篇幅太长。不太适合刚刚入门springboot的学习者。
本次案例链接:
https://github.com/LuckToMeet-Dian-N/springboot_Learn_6
开发环境:
win10+IntelliJ IDEA +JDK1.8
springboot版本:springboot 1.5.14 ——2.0后的springboot增加了挺多新特性,暂时先不做了解
项目结构:
配置文件准备:
pom.xml文件:
<?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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.wen</groupId>
<artifactId>demo</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>
<name>demo</name>
<description>Demo project for Spring Boot</description>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.5.14.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
<java.version>1.8</java.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.mybatis.spring.boot</groupId>
<artifactId>mybatis-spring-boot-starter</artifactId>
<version>1.3.2</version>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<scope>runtime</scope>
</dependency>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<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>
application.properties:
spring.datasource.url=jdbc:mysql://localhost:3306/xmsx
spring.datasource.username=root
spring.datasource.password=123456
spring.datasource.driver-class-name=com.mysql.jdbc.Driver
# 配置资源文件的路径(properties写了中文会给转码。所以这里只是显示在博客上,github上不出现这句)
# Configuring the path of a resource file
mybatis.config-locations=classpath:mybatis/sqlMapConfig.xml
mybatis.mapper-locations=classpath:mybatis/mapper/*.xml
mybatis.type-aliases-package=com.wen.test.vo
mybatis配置文件:
<!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN" "http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
<!-- 别名 -->
<typeAliases>
<package name="com.wen.test.vo" />
<!-- 为某个类起别名 -->
<!-- 扫描com.wen.test.vo包下的类 别名好像是首字母小写的 -->
</typeAliases>
</configuration>
mapper配置文件
<?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.wen.test.mapper.UserMapper">
<insert id="insertUser" parameterType="users">
INSERT INTO user VALUE(NULL ,#{phone},#{password})
</insert>
<select id="selectAllUsers" resultType="users">
SELECT * FROM user
</select>
</mapper>
mysql表设计:
user_id是自增列,所有插入的时候可以用null。
开始开发:
对应的Controller
package com.wen.test.controller;
import com.wen.test.service.UserService;
import com.wen.test.vo.Users;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;
import java.util.List;
@RestController
public class UserController {
@Autowired
UserService userService;
/**
* 插入数据
*/
@GetMapping(value = "test")
public String insertUser(Users users){
userService.insertUsers(users);
return "插入成功";
}
/**
* 为了方便测试。就只用GET请求来请求数据。。。
* @param users
* @return
*/
@GetMapping(value = "all")
public List<Users> selectALL(Users users){
return userService.selectAllUsers();
}
}
service接口
package com.wen.test.service;
import com.wen.test.vo.Users;
import java.util.List;
public interface UserService {
Integer insertUsers(Users users);
List<Users> selectAllUsers();
}
service实现类
package com.wen.test.service.Impl;
import com.wen.test.mapper.UserMapper;
import com.wen.test.service.UserService;
import com.wen.test.vo.Users;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;
import java.util.List;
@Service
public class UserServiceImpl implements UserService{
@Autowired
UserMapper userMapper;
@Override
@Transactional //开启事务
public Integer insertUsers(Users users) {
System.out.println("插入成功"+ userMapper.insertUser(users));
return 1;
}
@Override
public List<Users> selectAllUsers() {
return userMapper.selectAllUsers();
}
}
mapper接口
package com.wen.test.mapper;
import com.wen.test.vo.Users;
import java.util.List;
public interface UserMapper {
Integer insertUser(Users users);
List<Users> selectAllUsers();
}
实体VO:
package com.wen.test.vo;
import lombok.Data;
import java.io.Serializable;
@Data
public class Users implements Serializable{
private Integer user_id;
private String phone;
private String password;
}
DemoApplication类
package com.wen.test;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
@SpringBootApplication
@MapperScan("com.wen.test.mapper")
public class DemoApplication {
public static void main(String[] args) {
SpringApplication.run(DemoApplication.class, args);
}
}
其中@MapperScan("com.wen.test.mapper") 是扫描这个位置下所有的mapper,算是一种偷懒。如果不想偷懒,可以在每个Mapper接口上加@Mapper
测试:
测试插入数据库接口:
测试查询所有用户接口:(只截图部分)
总结:
springboot整合mybatis,开始我是用注解形式的,当然,这类型注解和springdata-jpa真的是差不多,看一眼就直接可以开发。但是,做复杂查询的时候,短板就出来了。当然,mybatis做的也是不错,提供了@Results等注解做返回值映射。但是我还是比较喜欢用xml,这个看个人吧。
如果还没学习过Mybatis的同学,可以去看看一些大佬的博客,相对来说Mybatis学习门栏很低很低,学习成本也是很低的,特别是springboot自动化配置之后,根本见不到什么配置。小编之前就学了Mybatis,但是太懒了,没有写相关学习总结