SpringBoot 整合Mybatis
前题：
借助：IntelliJ IDEA，Maven构建工具，以及基于SpringBoot 2.3.4。
官人如需使用 Maven 请阅读教程：Maven 构建工具的下载与安装
官人如需使用 IDEA 请阅读教程：IntelliJ IDEA
更多干货：
请阅读：《穿越SpringBoot》系列文章
请参考：Java学习资料
背景：
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，几乎避免了所有的 JDBC 代码和手动设置参数以及获取结果集，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 Old Java Objects,普通的 Java对象)映射成数据库中的记录.
使用
目录结构：
pom.xml 依赖：
在pom.xml中添加Mybatis的依赖包mybatis-spring-boot-starter，该包拥有自动装配的特点
但是涉及到myBatis启动器适应SpringBoot的版本问题：
<?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>2.3.4.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<groupId>com.example</groupId>
<artifactId>jdbc</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>jdbc</name>
<description>Demo project for Spring Boot</description>
<properties>
<java.version>1.8</java.version>
</properties>
<dependencies>
<!--mybatis-->
<dependency>
<groupId>org.mybatis.spring.boot</groupId>
<artifactId>mybatis-spring-boot-starter</artifactId>
<version>2.1.3</version>
</dependency>
<!--jdbc-->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-jdbc</artifactId>
</dependency>
<!--web -->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<!--mysql-->
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<scope>runtime</scope>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-thymeleaf</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-configuration-processor</artifactId>
<optional>true</optional>
</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>
<exclusions>
<exclusion>
<groupId>org.junit.vintage</groupId>
<artifactId>junit-vintage-engine</artifactId>
</exclusion>
</exclusions>
</dependency>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.13</version>
<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配置文件
#端口
server.port=9090
spring.datasource.username=root
spring.datasource.password=root
spring.datasource.url=jdbc:mysql:///test?serverTimezone=GMT%2B8&useUnicode=true&characterEncoding=utf-8
#静态资源缓冲
spring.thymeleaf.cache=false
mybatis.mapper-locations=classpath:mappers/*.xml
mybatis.type-aliases-package=com.example.jdbc.domain
# 驼峰命名规范
mybatis.configuration.map-underscore-to-camel-case=true
编写controller
package com.example.jdbc.controller;
import com.example.jdbc.domain.User;
import com.example.jdbc.service.UserService;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.GetMapping;
import javax.annotation.Resource;
import java.util.List
@Controller
public class DemoController {
@Resource
private UserService userService;
@GetMapping("/demo1")
public String demo1(Model model){
List<User> all = userService.getAll();
System.out.println(all);
model.addAttribute("user",all);
return "index";
}
}
编写service
package com.example.jdbc.service;
import com.example.jdbc.domain.User;
import java.util.List;
public interface UserService {
List<User> getAll();
}
package com.example.jdbc.service.impl;
import com.example.jdbc.dao.UserDao;
import com.example.jdbc.domain.User;
import com.example.jdbc.mapper.UserMapper;
import com.example.jdbc.service.UserService;
import org.springframework.stereotype.Service;
import javax.annotation.Resource;
import java.util.List;
@Service
public class UserServiceImpl implements UserService {
@Resource
private UserMapper userMapper;
@Override
public List<User> getAll(){
List<User> all = userMapper.getAll();
return all;
}
}
演示两种方式:
编写mapper
第一种是基于mybatis3.x版本后提供的注解方式
package com.example.jdbc.mapper;
import com.example.jdbc.domain.User;
import org.apache.ibatis.annotations.Mapper;
import org.apache.ibatis.annotations.Select;
@Mapper
public interface UserMapper {
@Select("SELECT * FROM user")
List<User> getAll();
int insert(User user);
}
编写mapper.xml
第二种是早期写法，将SQL写在 XML 中
<?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.example.jdbc.mapper.UserMapper">
<insert id="insert" parameterType="com.example.jdbc.domain.User">
INSERT INTO user(name,password,age) VALUES (#{name},#{password},#{age})
</insert>
</mapper>
编写index页面
<!DOCTYPE html>
<html xmlns:th="http://www.thymeleaf.org">
<head>
<meta charset="UTF-8">
<title>Title</title>
</head>
<link rel="stylesheet" href="style.css">
<body>
<h1>测试SpringBoot 整合mybatis</h1>
<ul>
<li th:each="u : ${user}" th:object="${u}">
<div>
<span th:text="*{name}">水果</span>
<span th:text="${u.age}">价格</span>
</div>
</li>
</ul>
</body>
</html>
编写JdbcApplicationTests 测试类
package com.example.jdbc;
import com.example.jdbc.domain.User;
import com.example.jdbc.mapper.UserMapper;
import org.junit.jupiter.api.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.junit4.SpringRunner;
import javax.annotation.Resource;
import java.sql.SQLException;
@RunWith(SpringRunner.class)
@SpringBootTest
class JdbcApplicationTests {
@Resource
private UserMapper userMapper;
@Test
void contextLoads() throws SQLException {
User user = new User();
user.setName("测试9");
user.setPassword("123");
user.setAge(25);
int insert = userMapper.insert(user);
System.out.println(insert);
}
}
测试：
访问:http://localhost:9090/demo1
