《穿越SpringBoot 》 第三章-SpringBoot访问数据库 | 第3节- SpringBoot 整合MyBatis-Plus

SpringBoot 整合MyBatis-Plus

前题更多干货官网使用目录结构pom.xml依赖application.properties 配置文件编写实体类编写mapper接口编写service编写controller编写index.html测试 总结

前题

基于：IntelliJ IDEA、Maven构建工具、JDK1.8、SpringBoot 2.3.4编写。

官人如需使用 Maven 请阅读教程：Maven 构建工具的下载与安装

官人如需使用 IDEA 请阅读教程：IntelliJ IDEA

更多干货

请阅读：《穿越SpringBoot》系列文章

请参考：Java学习资料

官网

官网地址：http://mybatis.plus/

使用

目录结构

pom.xml依赖

<?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.example</groupId> <artifactId>mybatisplus</artifactId> <version>0.0.1-SNAPSHOT</version> <name>mybatisplus</name> <description>Demo project for Spring Boot</description> <properties> <java.version>1.8</java.version> </properties> <dependencies> <!--mybatis-plus--> <dependency> <groupId>com.baomidou</groupId> <artifactId>mybatis-plus-boot-starter</artifactId> <version>3.4.0</version> </dependency> <!--mysql--> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> <scope>runtime</scope> <version>5.1.39</version> </dependency> <!--thymeleaf--> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-thymeleaf</artifactId> </dependency> <!--web--> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-configuration-processor</artifactId> <optional>true</optional> </dependency> <!--lombok--> <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> <exclusions> <exclusion> <groupId>org.junit.vintage</groupId> <artifactId>junit-vintage-engine</artifactId> </exclusion> </exclusions> </dependency> </dependencies> <build> <plugins> <plugin> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-maven-plugin</artifactId> </plugin> </plugins> </build> </project>

application.properties 配置文件

连接数据库:

spring.datasource.url=jdbc:mysql:///test?characterEncoding=utf-8&useSSL=false spring.datasource.driver-class-name=com.mysql.jdbc.Driver spring.datasource.username=root spring.datasource.password=root #mysql #spring.datasource.type=com.alibaba.druid.pool.DruidDataSource #spring.datasource.url=jdbc:mysql:///tset?serverTimezone=Hongkong&useUnicode=true&characterEncoding=utf8 #spring.datasource.username=root #spring.datasource.password=password #spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver #spring.datasource.dbcp2.min-idle=5 #spring.datasource.dbcp2.initial-size=5 #spring.datasource.dbcp2.max-total=5 #spring.datasource.dbcp2.max-wait-millis=200 #mybatis-plus # 如果是放在src/main/java目录下 classpath:/com/example/*/mapper/*Mapper.xml # 如果是放在resource目录 classpath:/mapper/*Mapper.xml # mybatis-plus.mapper-locations=classpath:/com/springboot/study/mapper/*Mapper.xml #实体扫描，多个package用逗号或者分号分隔 # mybatis-plus.type-aliases-package=com.springboot.study.entity #主键类型 0:"数据库ID自增", 1:"用户输入ID",2:"全局唯一ID (数字类型唯一ID)", 3:"全局唯一ID UUID"; # mybatis-plus.global-config.id-type=3 #字段策略 0:"忽略判断",1:"非 NULL 判断"),2:"非空判断" #mybatis-plus.global-config.field-strategy=2 #驼峰下划线转换 #mybatis-plus.global-config.db-column-underline=true #mp2.3+ 全局表前缀 mp_ #mybatis-plus.global.table-prefix: mp_ #刷新mapper 调试神器 #mybatis-plus.global-config.refresh-mapper=true #数据库大写下划线转换 # mybatis-plus.global-config.capital-mode=true # Sequence序列接口实现类配置 # mybatis-plus.global-config.key-generator=com.example.mybatisplus.incrementer.OracleKeyGenerator #逻辑删除配置（下面3个配置） #mybatis-plus.global-config.logic-delete-value=1 #mybatis-plus.global-config.logic-not-delete-value=0 #mybatis-plus.global-config.sql-injector=com.example.springboot.MyMetaObjectHandler #配置返回数据库(column下划线命名&&返回java实体是驼峰命名)，自动匹配无需as（没开启这个，SQL需要写as： select user_id as userId） mybatis-plus.configuration.map-underscore-to-camel-case=true #mybatis-plus.configuration.cache-enabled=false #配置JdbcTypeForNull, oracle数据库必须配置 #mybatis-plus.configuration.jdbc-type-for-null=null

更多 CRUD操作访问：http://mybatis.plus/guide/crud-interface.html#service-crud-%E6%8E%A5%E5%8F%A3

编写实体类

@Data @TableName(“user”) //对应数据库表名称 @TableId(“id”)//指定主键 @TableField(“s_sex”)指定表字段和该变量对应

package com.example.mybatisplus.entity; import com.baomidou.mybatisplus.annotation.TableId; import com.baomidou.mybatisplus.annotation.TableName; import lombok.Data; @Data @TableName("user") //对应数据库表名称 public class User { @TableId("id")//指定主键 private Integer id; private String name; private String password; private Integer age; //指定表字段和该变量对应 //@TableField("s_sex") }

编写mapper接口

@Mapper注解 继承mybatisplus提供的 BaseMapper< User > 需指定实体对象类型

package com.example.mybatisplus.mapper; import com.baomidou.mybatisplus.core.mapper.BaseMapper; import com.example.mybatisplus.entity.User; import org.apache.ibatis.annotations.Mapper; @Mapper public interface UserMapper extends BaseMapper<User> { }

编写service

继承IService< User >

package com.example.mybatisplus.service; import com.baomidou.mybatisplus.extension.service.IService; import com.example.mybatisplus.entity.User; import org.springframework.stereotype.Service; @Service public interface UserService extends IService<User> { }

继承 ServiceImpl< UserMapper, User> 指定mapper对象和要操作的对象

package com.example.mybatisplus.service.impl; import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl; import com.example.mybatisplus.entity.User; import com.example.mybatisplus.mapper.UserMapper; import com.example.mybatisplus.service.UserService; import org.springframework.stereotype.Service; @Service public class UserServiceImpl extends ServiceImpl<UserMapper, User> implements UserService { }

编写controller

package com.example.mybatisplus.controller; import com.example.mybatisplus.entity.User; import com.example.mybatisplus.service.UserService; import org.springframework.stereotype.Controller; import org.springframework.ui.Model; import org.springframework.web.bind.annotation.GetMapping; import javax.annotation.Resource; import java.util.List; @Controller public class DemoController { @Resource private UserService userService; @GetMapping("/demo1") public String demo1(Model model){ List<User> users = userService.list(); model.addAttribute("user",users); System.out.println(users); return "index"; } }

编写index.html

<!DOCTYPE html> <html xmlns:th="http://www.thymeleaf.org"> <head> <meta charset="UTF-8"> <title>Title</title> </head> <link rel="stylesheet" href="style.css"> <body> <h1>测试SpringBoot 整合mybatis-plus</h1> <ul> <li th:each="u : ${user}" th:object="${u}"> <div> <span th:text="*{name}"></span> <span th:text="${u.age}"></span> </div> </li> </ul> </body> </html>

测试

浏览器访问:http://localhost:8080/demo1

总结

待完善…

本教程基于最新的spring-boot-starter-parent：2.3.4RELEASE编写,目前很多大佬都写过关于SpringBoot的教程了，如有雷同，请多多包涵.