springboot+mybatis-plus项目创建整个完成过程和注意事项

冷不防 2024-03-17 21:37 54阅读 0赞

### 1：application.yml文件配置 ###

server:
      port: 8088
      servlet:
        context-path: /test
    spring:
      datasource:
        name: text  #????
        url: jdbc:mysql://localhost:3306/dsdd?serverTimezone=GMT&useUnicode=true&characterEncoding=utf-8&useSSL=true
        username: root  #??
        password: root  #??
        #要添加mysql-connector-java依赖
        driver-class-name: com.mysql.cj.jdbc.Driver  #????com.mysql.jdbc.Driver
    
    
    mybatis-plus:
      #这个作用是扫描xml文件生效可以和mapper接口文件使用，
      #如果不加这个,就无法使用xml里面的sql语句
      #启动类加了@MapperScan是扫描指定包下mapper接口生效，如果不用@MapperScan可以在每一个mapper接口添加@Mapper注解
      mapper-locations: classpath*:com/example/poi/mapper/**/xml/*Mapper.xml
      global-config:
        # 关闭MP3.0自带的banner
        banner: false
        db-config:
          #主键类型
          id-type: ASSIGN_ID
          # 默认数据库表下划线命名
          table-underline: true
      configuration:
        # 这个配置会将执行的sql打印出来，在开发或测试的时候可以用
        log-impl: org.apache.ibatis.logging.stdout.StdOutImpl
        # 返回类型为Map,显示null对应的字段
        call-setters-on-nulls: true
    
    logging:
      level:
      	# 日记级别，设置的越小捕抓的信息越多 trace<debug<info<warn<error
        #root 键指定了根日志记录器的级别为 INFO
        root: INFO
        #com.baomidou.mybatisplus 包下的日志记录器级别为 DEBUG
        com.baomidou.mybatisplus: INFO
      file:
      	#保留了最近 30 天的日志
        max-history: 30
        #每个日记大小，当日记达到100M但还没到达下一天就生成一个新的文件按i序号
        max-size: 100MB
        #保存日记实际路径，确保指定的路径对应的目录已存在，并具有具有的写入权限
        pattern: /home/app/logs//mybatis-%d{
        yyyy-MM-dd}-%i.log
        #设置日志文件夹存储总大小的上限，超过就删除旧的
        total-size-cap: 1GB

### 2：pom.xml文件依赖管理，web服务必须按以下依赖 ###

<?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>2.2.7.RELEASE</version>
            <relativePath/> 
        </parent>
        <groupId>com.example</groupId>
        <artifactId>poi</artifactId>
        <version>0.0.1-SNAPSHOT</version>
        <name>poi</name>
        <description>poi</description>
        <properties>
            <java.version>8</java.version>
        </properties>
        <dependencies>
        
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter</artifactId>
            </dependency>
    
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-test</artifactId>
                <scope>test</scope>
            </dependency>
            
            <dependency>
                <groupId>com.baomidou</groupId>
                <artifactId>mybatis-plus-boot-starter</artifactId>
                <version>3.5.1</version>
            </dependency>
    
            <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>8.0.13</version>
            </dependency>
            
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-web</artifactId>
            </dependency>
            
        </dependencies>
    
        <build>
            <plugins>
                <plugin>
                    <groupId>org.springframework.boot</groupId>
                    <artifactId>spring-boot-maven-plugin</artifactId>
                </plugin>
            </plugins>
    
            <resources>
                <resource>
                    <directory>src/main/resources</directory>
                    <includes>
                        <include>**/*.properties</include>
                        <include>**/*.yml</include>
                        <include>**/*.xml</include>
                    </includes>
                    <filtering>true</filtering>
                </resource>
                <resource>
                    <directory>src/main/java</directory>
                    <includes>
                        <include>**/*.properties</include>
                        <include>**/*.xml</include>
                    </includes>
                    <filtering>true</filtering>
                </resource>
            </resources>
    
        </build>
    
    </project>

### 注意：1-使用web服务controller访问必须导入以下依赖 ###

<dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-web</artifactId>
            </dependency>

### 注意：2-使用mybatis-plus必须导入以下依赖(不要使用spring的mybatis，不然和spring本身数据库管理冲突，还有就是注意使用springboot版本和mybatis版本问题，建议都是使用mybatis-plus，不然使用mybatis可能出现sqlFactory找不到等问题) ###

<dependency>
                <groupId>com.baomidou</groupId>
                <artifactId>mybatis-plus-boot-starter</artifactId>
                <version>3.5.1</version>
            </dependency>

### 注意：3-打开项目的target目录，观察里面是否有对应的××Mapper.xml文件，若没有，则在pom.xml文件中加入如下配置 ###

<build>
    		<resources>
                <resource>
                    <directory>src/main/resources</directory>
                    <includes>
                        <include>**/*.properties</include>
                        <include>**/*.yml</include>
                        <include>**/*.xml</include>
                    </includes>
                    <filtering>true</filtering>
                </resource>
                <resource>
                    <directory>src/main/java</directory>
                    <includes>
                        <include>**/*.properties</include>
                        <include>**/*.xml</include>
                    </includes>
                    <filtering>true</filtering>
                </resource>
            </resources>

### 3：项目结构图 ###

![在这里插入图片描述][4d5ce54f67274dae93cdd1c23651ddcf.png_pic_center]

### 4：启动类 ###

package com.example.poi;
    
    import org.mybatis.spring.annotation.MapperScan;
    import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    
    @SpringBootApplication
    @MapperScan(basePackages = "com.example.poi.mapper")
    public class PoiApplication {
        
        public static void main(String[] args) {
        
            SpringApplication.run(PoiApplication.class, args);
        }
    }

### 5：controller类 ###

package com.example.poi.controller;
    
    import com.example.poi.service.ITest;
    import org.springframework.web.bind.annotation.GetMapping;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RestController;
    
    import javax.annotation.Resource;
    import javax.servlet.http.HttpServletResponse;
    
    /**
     * @Author xu
     * @create 2023/7/5 01
     */
    
    @RestController
    @RequestMapping("/customDemo")
    public class DemoTwoController {
        
    
        @Resource
        ITest iTest;
    
        @GetMapping("/export")
        public void exportExcel(HttpServletResponse response) {
        
    
            String age = "20";
            String phone = iTest.getPhone(age);
        }
    }

### 6：service和impl类 ###

package com.example.poi.service;
    
    import com.baomidou.mybatisplus.extension.service.IService;
    import com.example.poi.entity.EntityDemo;
    
    /**
     * @Author xu
     * @create 2023/7/14 22
     */
    public interface ITest extends IService<EntityDemo> {
        
    
        String getPhone(String age);
    
    }

package com.example.poi.service.impl;
    
    import com.baomidou.mybatisplus.core.conditions.query.LambdaQueryWrapper;
    import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
    import com.example.poi.entity.EntityDemo;
    import com.example.poi.mapper.TestMapper;
    import com.example.poi.service.ITest;
    import org.springframework.stereotype.Service;
    
    import javax.annotation.Resource;
    
    /**
     * @Author xu
     * @create 2023/7/14 22
     */
    @Service
    public class TestImpl extends ServiceImpl<TestMapper, EntityDemo> implements ITest {
        
    
        @Resource
        TestMapper testMapper;
    
        @Override
        public String getPhone(String age) {
        
    
            EntityDemo list = testMapper.selectName();
    
            this.baseMapper.selectOne(new LambdaQueryWrapper<EntityDemo>().eq(EntityDemo::getAge, age));
    
    
            return "entityDemo.getPhone()";
        }
    }

### 7：mapper类和xml文件 ###

package com.example.poi.mapper;
    
    import com.baomidou.mybatisplus.core.mapper.BaseMapper;
    import com.example.poi.entity.EntityDemo;
    
    /**
     * @Author xu
     * @create 2023/7/14 22
     */
    //@Mapper
    public interface TestMapper  extends BaseMapper<EntityDemo> {
        
    
    
        //@Select("select * from entity_demo where age='20'")
        EntityDemo selectName();
    }

<?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.poi.mapper.TestMapper">
    
        <select id="selectName" resultType="com.example.poi.entity.EntityDemo">
            select * from entity_demo where age='20'
        </select>
    </mapper>

[4d5ce54f67274dae93cdd1c23651ddcf.png_pic_center]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/14/8cb763b95e5348fdbe2dd867abd7ae11.png