新建我的项目
临时只须要勾选webjar包即可
导入jt.sql的数据库
筹备数据库工具~~~~
连贯数据库
增加jar包文件
<?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>2.3.4.RELEASE</version> <relativePath/> <!-- lookup parent from repository --> </parent> <groupId>com.jt</groupId> <artifactId>springboot_demo2_mybatis</artifactId> <version>0.0.1-SNAPSHOT</version> <name>springboot_demo2_mybatis</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> <exclusions> <exclusion> <groupId>org.junit.vintage</groupId> <artifactId>junit-vintage-engine</artifactId> </exclusion> </exclusions> </dependency> <!--引入插件lombok 主动的set/get/构造方法插件 --> <dependency> <groupId>org.projectlombok</groupId> <artifactId>lombok</artifactId> </dependency> <!--引入数据库驱动 --> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> <scope>runtime</scope> </dependency> <!--springBoot数据库连贯 --> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-jdbc</artifactId> </dependency> <!--spring整合mybatis 临时 --> <dependency> <groupId>org.mybatis.spring.boot</groupId> <artifactId>mybatis-spring-boot-starter</artifactId> <version>1.3.2</version> </dependency> </dependencies> <build> <plugins> <plugin> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-maven-plugin</artifactId> </plugin> </plugins> </build></project>编辑POJO对象
@Data@Accessors(chain = true)public class User implements Serializable { private Integer Id; private String name; private Integer age; private String sex;}编辑UserDao接口
@Mapper //将接口交给Spring治理public interface UserDao { //查问user表的所有的记录 @Select("select * from user") List<User> findAll();}编辑测试类
package com.jt;import com.jt.dao.UserDao;import com.jt.pojo.User;import org.junit.jupiter.api.Test;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.boot.test.context.SpringBootTest;import java.util.List;@SpringBootTestclass SpringbootDemo2MybatisApplicationTests { @Autowired private UserDao userDao; @Test public void testFind(){ List<User> userList = userDao.findAll(); System.out.println(userList); }}对于Mybatis配置阐明
前提:Mybatis进行映射时必须满足属性名称统一业务阐明:表: user_id user_name对象: userId userName解决方案: 开启mybatis驼峰规定映射
原理:字段名称user_id去除‘——’下滑线userid而后首字母大写userId 属性userId只有名称统一,则能够主动映射.
注意事项: 如果开启驼峰规定,则必须满足要求.
问: 对象的属性user_id 与字段user_id是否映射? 不能映射！
server: port: 8090 #定义端口号 servlet: context-path: / #定义我的项目公布门路spring: datasource: #driver-class-name: com.mysql.jdbc.Driver 通知springboot程序采纳默认的配置 url: jdbc:mysql://127.0.0.1:3306/jtdb?serverTimezone=GMT%2B8&useUnicode=true&characterEncoding=utf8&autoReconnect=true&allowMultiQueries=true username: root password: rootmybatis: #定义别名包 type-aliases-package: com.jt.pojo #加载user表的mapper文件 mapper-locations: classpath:/mybatis/mappers/*.xml #开启驼峰映射 configuration: map-underscore-to-camel-case: true对于数据库url阐明
1.时区设定
serverTimezone=GMT%2B8 %2B= +号
2.编码格局设定
useUnicode=true&characterEncoding=utf8
3.是否主动的从新链接
autoReconnect=true
4.是否容许批量操作
allowMultiQueries=true
对于Mapper注解优化阐明
因为每个接口都须要增加Mapper注解导致代码繁琐.能够采纳包扫描的形式动静导入 代码如下
@SpringBootApplication/***次要通知mapper的包门路,会主动的实现包扫描。*留神:~~~~这里的参数是要扫描的包门路~~~~*/@MapperScan("com.jt.dao") public class SpringbootDemo2MybatisApplication { public static void main(String[] args) { SpringApplication.run(SpringbootDemo2MybatisApplication.class, args); }}