idea springboot 查找数据库总结

首先目录结构如下：

根据自己数据库各属性写好pojo下的StudentTeac
service下的StudentService

impl下的
dao下的StudentMapper（注意Mapper注解）

Controller

StudentMapper.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.demodel.dao.StudentMapper">
    <select id="findAllStudent" resultType="com.example.demodel.pojo.StudentTeac">
        select * from student
    </select>

</mapper>

mapper namespace为StudentMapper路径
select id=“findAllStudent” resultType为StudentTeac路径

application.yml

spring:
  datasource:
    url: jdbc:mysql://localhost:3306/user?characterEncoding=UTF-8&serverTimezone=UTC
    username: root
    password:
    driver-class-name: com.mysql.jdbc.Driver

mybatis:
  mapper-locations: classpath:mapper/*.xml
  configuration:
    map-underscore-to-camel-case: true

configuration:
map-underscore-to-camel-case: true
因为数据库中有teacher_one等，识别"_" ——驼峰命名法

pom.xml配置

<?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>2.4.2</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.example</groupId>
    <artifactId>demodel</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>demodel</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>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
        </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>

        <!--内置tomcat对Jsp支持的依赖，用于编译Jsp-->
        <dependency>
            <groupId>org.apache.tomcat.embed</groupId>
            <artifactId>tomcat-embed-jasper</artifactId>
            <scope>provided</scope>
        </dependency>
        <!-- mybatis -->
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>2.1.4</version>
        </dependency>
        <!--引入jsp相关-->
        <dependency>
            <groupId>javax.servlet.jsp</groupId>
            <artifactId>jsp-api</artifactId>
            <version>2.2</version>
        </dependency>
        <!--引入Servlet-->
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>javax.servlet-api</artifactId>
            <version>3.1.0</version>
        </dependency>
        <!--引入jstl-->
        <dependency>
            <groupId>jstl</groupId>
            <artifactId>jstl</artifactId>
            <version>1.2</version>
        </dependency>

        <dependency>
            <groupId>org.testng</groupId>
            <artifactId>testng</artifactId>
            <version>7.3.0</version>
            <scope>test</scope>
        </dependency>

<!--            <dependency>-->
<!--                <groupId>org.springframework.cloud</groupId>-->
<!--                <artifactId>spring-cloud-starter-netflix-eureka-server</artifactId>-->
<!--            </dependency>-->

    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <configuration>
                    <excludes>
                        <exclude>
                            <groupId>org.projectlombok</groupId>
                            <artifactId>lombok</artifactId>
                        </exclude>
                    </excludes>
                </configuration>
            </plugin>
        </plugins>
    </build>

</project>