上週用vue把前臺搭建完成，這幾天想試試springboot訪問資料庫，好在終於實現了，挺有成就感。

idea整體架構

部分程式碼

application.yml

server:
  port: 8081
#mybatis配置
mybatis:
  mapper-locations: classpath:mybatis/mapper/*.xml  #修改為對應的mapper檔案路徑

spring:
  datasource:
    url: jdbc:mysql://127.0.0.1:3306/test?characterEncoding=utf8
    username: root
    password: 123456
 

pom.xml

<?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
 
.3</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.example</groupId>
    <artifactId>demo</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>demo</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-data-jpa</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-jdbc</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-thymeleaf</artifactId>
        </dependency>
        <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>

        <!-- mybatis-->
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>1.3.1</version>
        </dependency>

        <!--lombok-->
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.16.16</version>
            <scope>provided</scope>
        </dependency>


        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
            <exclusions>
                <exclusion>
                    <groupId>org.junit.vintage</groupId>
                    <artifactId>junit-vintage-engine</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
        <dependency>
            <groupId>org.xmlunit</groupId>
            <artifactId>xmlunit-core</artifactId>
        </dependency>
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.4.6</version>
        </dependency>
    </dependencies>

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

</project>

User

@Data // get/set 方法
@AllArgsConstructor//有參構造器
@NoArgsConstructor//無參構造器
@Table(name = "User")
public class User {
    private String cId;
    private String cUsername;

    private String cPwd;

    public String getcUsername() {
        return cUsername;
    }

    public void setcUsername(String cUsername) {
        this.cUsername = cUsername;
    }

    public String getcPwd() {
        return cPwd;
    }

    public void setcPwd(String cPwd) {
        this.cPwd = cPwd;
    }

    public String getcId() {
        return cId;
    }

    public void setcId(String cId) {
        this.cId = cId;
    }
}

CorsConfig(解決跨域)

@Configuration
public class CorsConfig {
    private CorsConfiguration buildConfig() {
        CorsConfiguration corsConfiguration = new CorsConfiguration();
        corsConfiguration.addAllowedOriginPattern("*");//允許任何域名
        corsConfiguration.addAllowedHeader("*");
        corsConfiguration.addAllowedMethod("*");
        corsConfiguration.setAllowCredentials(true);
        return corsConfiguration;
    }

    @Bean
    public CorsFilter corsFilter() {
        UrlBasedCorsConfigurationSource source = new UrlBasedCorsConfigurationSource();
        source.registerCorsConfiguration("/**", buildConfig());
        return new CorsFilter(source);

    }

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="queryAll" resultType="com.example.demo.bean.User">
  select * from users
 </select>
    <insert id="add" parameterType="com.example.demo.bean.User">
  insert into users values (#{username},#{password})
 </insert>
    <select id="queryByUsername" resultType="com.example.demo.bean.User">
  select * from users where cUsername=#{username}
 </select>
</mapper>

總結下思路
1、idea建立springboot專案
2、引入mybatis包到pom.xml
3、mysql建立表
4、搭建mybatis訪問資料庫環境，寫yml檔案 

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