本文为博主原创,未经允许不得转载:
1.创建一个spring boot的工程应用:
File ---- > New ----->Project ----> 然后选中Spring Initializr 继续创建:
2.添加spring boot ,mybatis plus 以及 mysql 相关的依赖:
<dependencies>
<!-- spring boot web启动 -->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</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>
<!-- mysql 数据库连接 -->
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<scope>runtime</scope>
</dependency>
<!-- mybatis plus 代码生成器 -->
<dependency>
<groupId>com.baomidou</groupId>
<artifactId>mybatis-plus-boot-starter</artifactId>
<version>3.2.0</version>
</dependency>
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>fastjson</artifactId>
<version>1.2.47</version>
</dependency>
<!-- https://mvnrepository.com/artifact/javax.persistence/persistence-api -->
<dependency>
<groupId>javax.persistence</groupId>
<artifactId>persistence-api</artifactId>
<version>1.0</version>
</dependency>
</dependencies>
3. spring boot 的配置文件中配置项目启动名称,端口号,数据库连接等:
此处需要注意的是:spring boot 项目的配置文件是application.properties ,不是bootstrap.yml,bootstrap.yml是spring cloud 中定义解析配置文件的格式
server.port=8002
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
spring.datasource.url=jdbc:mysql://127.0.0.1:3306/test?autoReconnect=true&useUnicode=true&characterEncoding=utf8&useSSL=false&serverTimezone=UTC
spring.datasource.username=root
spring.datasource.password=root
# mybatis plus 调用打印 sql
mybatis-plus.configuration.log-impl=org.apache.ibatis.logging.stdout.StdOutImpl
并启动项目,查看启动日志,会打印spring 以及 mybatis plus 的banner 图案
4.创建用户表,定义表结构如下:
CREATE TABLE `user` (
`id` bigint(20) NOT NULL COMMENT '主键ID',
`name` varchar(30) DEFAULT NULL COMMENT '姓名',
`age` int(11) DEFAULT NULL COMMENT '年龄',
`email` varchar(50) DEFAULT NULL COMMENT '邮箱',
PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf-8;
5. 业务代码:
5.1 创建实体类:
package com.example.demo.entity;
import lombok.Data;
import javax.persistence.Table;
@Data
@Table(name = "user")
public class User {
private Long id;
private String name;
private int age;
private String email;
}
需要继承BaseMapper
mapper接口需要在项目启动时进行加载扫描,可以使用两种方式进行配置:
第一种可以使用 @Mapper注解,在每个mapper接口进行注解,第二种可以在启动类上使用 @MapperScan 注解,其中的值为mapper的包路径
其中@Repository 表示持久层
package com.example.demo.mapper;
import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import com.example.demo.entity.User;
import org.apache.ibatis.annotations.Mapper;
import org.springframework.stereotype.Repository;
@Repository
//@Mapper
public interface UserMapper extends BaseMapper<User> {
}
需要继承IService
package com.example.demo.service;
import com.baomidou.mybatisplus.extension.service.IService;
import com.example.demo.entity.User;
import java.util.List;
public interface UserService extends IService<User> {
/**
* query all
* @return
*/
List<User> queryAllUser();
}
需要继承 ServiceImpl
package com.example.demo.service.impl;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.example.demo.entity.User;
import com.example.demo.mapper.UserMapper;
import com.example.demo.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import java.util.List;
@Service
public class UserServiceImpl extends ServiceImpl<UserMapper, User> implements UserService {
@Autowired
private UserMapper userMapper;
@Override
public List<User> queryAllUser() {
return userMapper.selectList(null);
}
}
5.5 创建controller
package com.example.demo.controller;
import com.example.demo.entity.User;
import com.example.demo.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import java.util.List;
@RestController
@RequestMapping("/user")
public class UserInfoController {
@Autowired
private UserService userService;
@RequestMapping("/queryAllUser")
public List<User> queryAllUser(){
List<User> userList = userService.queryAllUser();
return userList;
}
}
6.测试类
测试类需要添加spring boot 的test依赖,其中已经依赖过了junit test 的依赖,不需要再进行单独添加。
package com.example.demo;
import com.alibaba.fastjson.JSON;
import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
import com.example.demo.controller.UserInfoController;
import com.example.demo.entity.User;
import com.example.demo.mapper.UserMapper;
import com.example.demo.service.UserService;
import lombok.extern.slf4j.Slf4j;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import java.util.List;
@Slf4j
@SpringBootTest
class DemoApplicationTests {
@Autowired
private UserMapper userMapper;
@Autowired
private UserService userService;
@Autowired
private UserInfoController userInfoController;
@Test
void test() {
QueryWrapper<User> wrapper = new QueryWrapper<>();
wrapper.eq("name", "2");
User user = userMapper.selectOne(wrapper);
log.info("userMapper.selectOne result is {}", JSON.toJSONString(user));
int count = userService.count();
System.out.println(count);
log.info("userService.count() result is {}", count);
List<User> userList = userInfoController.queryAllUser();
log.info("userInfoController.queryAllUser() result is {}", JSON.toJSONString(userList));
}
}
如果使用以上测试时,出现测试类中注入的bean一直为空时,可使用下面的方式:
@RunWith(SpringRunner.class)
@SpringBootTest(classes = GeneratorApp.class, webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT)
public class UserTest {
@Autowired
private UserService userService;
}
执行以上测试类截图:
7. 配置 mybatis plus 的分页
package com.example.demo.config;
import com.baomidou.mybatisplus.extension.plugins.PaginationInterceptor;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
@Configuration
public class MybatisPlusConfig {
// 分页插件
@Bean
public PaginationInterceptor paginationInterceptor() {
return new PaginationInterceptor();
}
}
通过 junit 进行调试
@Test
void testPage() {
Page<User> page = new Page<>(1, 5);
IPage<User> paVo = userMapper.selectPage(page, null);
log.info("------------------{}", JSON.toJSONString(paVo));
}
mybatis plus 分页之后的格式如下:
{
"current": 1,
"orders": [],
"pages": 1,
"records": [{
"age": 3,
"email": "4",
"id": 1,
"name": "2"
}, {
"age": 23,
"email": "344",
"id": 1352980081638248450,
"name": "test"
}, {
"age": 23,
"email": "344",
"id": 1352980446211342337,
"name": "test"
}, {
"age": 23,
"email": "344",
"id": 1352980660057944066,
"name": "test"
}],
"searchCount": true,
"size": 5,
"total": 4
}
搭建框架过程中遇到的坑:
1. spring boot start启动的依赖是 spring-boot-starter-web ,不是 spring-boot-starter
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
2. spring boot 默认解析的配置文件是 application.properties 文件,不是bootstrap.yaml , bootstrap.yaml 是spring cloud 中加载解析的配置文件格式