SpringBoot 快速入门

1.1 快速构建SpringBoot

1.1.1 选择构建类型

1.1.2 项目描述

1.1.3 指定版本和依赖

1.1.4 创建一个controller 类

1.1.5 效果如下

1.1.6 文件下的src目录

springboot 常用注解 @Configuration 和 @Bean

1.1.6 热加载

1.1.7 修改setting 中配置

1.1.8 重新构建项目

SpringBoot Mybatis

2.1 快速构建SpringBoot

  <?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>2.4.0</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.first</groupId>
    <artifactId>project_first</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>project_first</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <!--热加载-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <optional>true</optional>
        </dependency>
        <!--mysql-->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
        </dependency>
        <!--        druid连接-->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid-spring-boot-starter</artifactId>
            <version>1.1.10</version>
        </dependency>
        <!--        mybatis-->
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>1.3.2</version>
        </dependency>

<!--json-->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>fastjson</artifactId>
            <version>1.2.47</version>
        </dependency>
<!--        -->
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <version>2.2.6.RELEASE</version>
            </plugin>
        </plugins>
    </build>

</project>

2.1 Mybatis 注解增删查改

2.1.1 controller 控制层

 /**
     * @Description:查找所有用户
     */
    @RequestMapping("/getAlluser")
    public String findAll() {
        System.out.println("查询所有");
        List<StudentBean> userList = userService.findAll();
        for (StudentBean user : userList) {
            System.out.println("用户：" + user);
        }
        Map<String, Object> hash = new HashMap<>();
        hash.put("data", userList);
        hash.put("code", 200);
        String data_json = JSON.toJSONString(hash);
        return data_json;
    }

2.1.2 mapper mapper

增删改查 @Insert @Delete @Update @Select 还需要在启动类添加@MapperScan 注解

@SpringBootApplication
@MapperScan("com.first.project_first.*")
public class ProjectFirstApplication {
    public static void main(String[] args) {
        SpringApplication.run(ProjectFirstApplication.class, args);
    }

}

@Mapper
public interface StudentMapper {
    List<StudentBean> findAll();

    @Select("select * from easyuser")
    List<StudentBean> findAlls();

    @Select("select * from studentuser where id = #{id}")
    StudentBean findById(@Param("id") int id);

    @Insert("insert into studentuser(username,create_time) values(#{username},#{create_time})")
    int insert(@Param("username") String name, @Param("create_time") String create_time);

    @Update("update studentuser set username=#{username} where id=#{id}")
    int update(StudentBean user);

    @Delete("delete from studentuser where id=#{id}")
    int delete(int id);
}

2.1.3 service UserService

@Service
public class UserService {
    @Autowired
    private StudentMapper userMapper;

    public List<StudentBean> findAll() {
        return userMapper.findAlls();
    }

    public StudentBean findById(int id) {
        return userMapper.findById(id);
    }

    public int insert(String name, String createtime) {
        return userMapper.insert(name, createtime);
    }

    public int update(StudentBean user) {
        return userMapper.update(user);
    }

    public int delete(int id) {
        return userMapper.delete(id);
    }
}

2.1.4 resource 资源文件夹下的

<?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.first.project_first.mapper.StudentMapper">
<!--    List<StudentBean> findAll();-->
    <select id="findAll" resultType="com.first.project_first.bean.StudentBean">
        select * from easyuser
    </select>
<!---->
</mapper>

2.1.5 数据库配置 application-dev.yml

server:
  # 项目端口
  port: 8091
  servlet:
  # 项目路径
    context-path: /

# 连接数据库的信息
spring:
  datasource:
    driver-class-name: com.mysql.cj.jdbc.Driver
    url: jdbc:mysql:///easyproject?serverTimezone=UTC
    username: root
    password: root
    type: com.alibaba.druid.pool.DruidDataSource
  mvc:
    # 视图的前缀和后缀
    view:
      prefix: /WEB-INF/
      suffix: .jsp

# mybatis配置
mybatis:
  mapper-locations: classpath:mapper/*.xml
  type-aliases-package: com.qf.firstspringboot.entity
  configuration:
    map-underscore-to-camel-case: true

# 查看sql语句
logging:
  level:
    com.qf.firstspringboot.mapper: DEBUG

2.1.6 运行结果

代码连接地址 gitee.com/guaishoubro…