SpringBoot基础入门

Posted 2020-11-23 wydtian924128

之前本来一直在学SSM，但是依赖太多，出错也是一大把的，对于自学，看文档的我，调试得都快哭了。还有三周就课程设计了，所以临时学学springboot。之前有篇文章说， SSM就好像开手动挡的汽车,需要踩离合,挂档,给油车才能开动。而springboot就好像自动挡的汽车,给油就走,踩刹车就停。经过一下午的努力，感觉终于看到门了，所有写来复习一遍。

基于ideal，安装很简单，在这勾上web就可以了

 

 

 

 

 

 pom.xml添加依赖

        <!--        mybatis-->
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>2.1.1</version>
        </dependency>
        <!--        mysql-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-jdbc</artifactId>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
        </dependency>
        <!--        跳转界面-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-thymeleaf</artifactId>
        </dependency>
        <!--        热部署-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <optional>true</optional>
            <scope>true</scope>
        </dependency>

application.properties

#server.port= #改变端口号
#server.servlet.context-path=/demo #加路径
#mysql配置文件
spring.datasource.url=jdbc:mysql://localhost:3306/test?serverTimezone=UTC
spring.datasource.username=root
spring.datasource.password=root
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
#mybatis
mybatis.mapper-locations= classpath:mapper/*.xml
mybatis.type-aliases-package=com.example.demo.entity
#跳转界面
spring.thymeleaf.prefix=classpath:/templates/

 添加mapper/UserMapper.xml

<?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.demo.mapper.UserMapper">
    <select id="findAll" resultType="User">
        SELECT * FROM user
    </select>
</mapper>

 MyController.class

package com.example.demo;

import com.example.demo.mapper.UserMapper;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;

@Controller
public class MyController {

    @Autowired
    private UserMapper userMapper;

    @RequestMapping("/login")
    public String Login(){
        System.out.println(userMapper.findAll());
        return "login";
    }
}

 mapper/UserMapper.class

package com.example.demo.mapper;

import com.example.demo.entity.User;
import org.apache.ibatis.annotations.Mapper;
import java.util.List;

@Mapper
public interface UserMapper {
    List<User> findAll();
}

然后就可以在控制台输出 和 页面的加载了

 

 热部署，勾上，ok。

 有问题可以评论问我，一起学习。