SpringBoot入门

1.mvn install可重新生成修改测试

2.

Caused by: org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type ‘com.zyd.mapper.xxMapper’ available: expected at least 1 bean which qualifies as autowire candidate. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}

由于spring 容器没有扫描到对应的信息

在启动类加上,即可

@MapperScan({"com.itheima"})

package com.itheima.springboot_8_mybatis;

import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
@MapperScan({"com.itheima"})

public class Springboot8MybatisApplication {

    public static void main(String[] args) {
        SpringApplication.run(Springboot8MybatisApplication.class, args);
    }

}

3.实例如下

package com.itheima.dao;

import com.itheima.domain.Book;
import org.apache.ibatis.annotations.Mapper;
import org.apache.ibatis.annotations.Select;

@Mapper
public interface BookDao {
    @Select("select * from tbl_book where id = #{id}")
    public Book getById(Integer id);
}

package com.itheima.domain;

public class Book {
    private Integer id;
    private String name;
    private String type;
    private String description;

    @Override
    public String toString() {
        return "Book{" +
                "id=" + id +
                ", name='" + name + ''' +
                ", type='" + type + ''' +
                ", description='" + description + ''' +
                '}';
    }

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getType() {
        return type;
    }

    public void setType(String type) {
        this.type = type;
    }

    public String getDescription() {
        return description;
    }

    public void setDescription(String description) {
        this.description = description;
    }
}

--启动类

package com.itheima.springboot_8_mybatis;

import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
@MapperScan({"com.itheima"})

public class Springboot8MybatisApplication {

    public static void main(String[] args) {
        SpringApplication.run(Springboot8MybatisApplication.class, args);
    }

}

--application.yml

spring:
  datasource:
    driver-class-name: com.mysql.cj.jdbc.Driver
    url: jdbc:mysql://localhost:3306/ssm_db?serverTimezone=UTC
    username: root
    password: caicai123
    type: com.alibaba.druid.pool.DruidDataSource

--test

package com.itheima.springboot_8_mybatis;

import com.itheima.dao.BookDao;
import com.itheima.domain.Book;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;

@SpringBootTest
class Springboot8MybatisApplicationTests {

    @Autowired
    private BookDao bookDao;

    @Test
    void testGetById() {
        Book book = bookDao.getById(1);
        System.out.println(book);
    }


}

--pom.xml

<?xml version="1.0" encoding="UTF-8"?>

    4.0.0
    
        org.springframework.boot
        spring-boot-starter-parent
        2.5.0
    
    com.itheima
    springboot_08_mybatis
    0.0.1-SNAPSHOT
    
        1.8
    
    
        
            org.mybatis.spring.boot
            mybatis-spring-boot-starter
            2.2.0
        

        
            mysql
            mysql-connector-java
            runtime
        

        
            org.springframework.boot
            spring-boot-starter-test
            test
        

        
            com.alibaba
            druid
            1.1.16
        
    

    
        
            
                org.springframework.boot
                spring-boot-maven-plugin
            
        
    

文件结构如下