springboot集成mybatis-plus 環境搭建（一）

項目結構：

集成mybatis-plus的坑挺多的，算是踩了一遍。

pom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>2.2.6.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>MPTest</groupId>
    <artifactId>mybatistest</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>mybatistest</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>1.8</java.version>
    </properties>
    <repositories><!-- 代碼庫 -->
        <repository>
            <id>maven-ali</id>
            <url>http://maven.aliyun.com/nexus/content/groups/public/</url>
            <releases>
                <enabled>true</enabled>
            </releases>
            <snapshots>
                <enabled>true</enabled>
                <updatePolicy>always</updatePolicy>
                <checksumPolicy>fail</checksumPolicy>
            </snapshots>
        </repository>
    </repositories>
    <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-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <scope>runtime</scope>
            <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>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
        </dependency>
        <!-- mp 依賴 -->
        <dependency>
            <groupId>com.baomidou</groupId>
            <artifactId>mybatis-plus-boot-starter</artifactId>
            <version>3.2.0</version>
        </dependency>
        <dependency>
            <groupId>net.sf.json-lib</groupId>
            <artifactId>json-lib</artifactId>
            <version>2.4</version>
            <classifier>jdk15</classifier>
        </dependency>
    </dependencies>

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

</project>

坑1：首先用idea默認的遠程倉庫下載的jar都有問題，將遠程倉庫地址改爲阿里雲的。

坑2：mybatis-plus不能和mybatis並存。

坑3：有一個類似的mybatis-plus包，但不是支持springboot的。

數據庫：

接下來是代碼：

1.entity:

@TableName("user_test")對應的是數據庫的表名，屬性對應字段

@TableId對應主鍵，value爲字段值，type爲生成策略auto爲自增

@TableField對應非主鍵

package mptest.mybatistest.entity;



import com.baomidou.mybatisplus.annotation.TableName;

import java.io.Serializable;

@TableName("user_test")
public class Good implements Serializable {
    @TableId(value = "id",type = IdType.AUTO)
    private int id;
	@TableField(value = "name")
    private String name;

	public int getId() {
		return id;
	}

	public void setId(int id) {
		this.id = id;
	}

	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}
}

 

 

2.mapper

繼承BaseMapper<Good>，注意加上mapper註解或者在啓動類加掃描mapper

package mptest.mybatistest.mapper;

import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import mptest.mybatistest.entity.Good;
import org.apache.ibatis.annotations.Mapper;
@Mapper
public interface GoodDao extends BaseMapper<Good> {
}

3.service

繼承IService<Good>

package mptest.mybatistest.service;
import com.baomidou.mybatisplus.extension.service.IService;
import mptest.mybatistest.entity.Good;

public interface IGoodService extends IService<Good> {
}

4.impl

繼承extends ServiceImpl<GoodDao,Good>，兩個參數一個爲dao，一個爲實體類

package mptest.mybatistest.service.impl;

import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import mptest.mybatistest.mapper.GoodDao;
import mptest.mybatistest.entity.Good;
import mptest.mybatistest.service.IGoodService;
import org.springframework.stereotype.Service;



@Service
public class GoodServiceImpl extends ServiceImpl<GoodDao,Good> implements IGoodService {

}

5.controller

goodService.list()爲IService接口自帶的方法。

package mptest.mybatistest.controller;

import mptest.mybatistest.service.IGoodService;
import net.sf.json.JSONArray;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import java.util.List;

@RestController
@RequestMapping("/work")
public class GoodsController {

    @Autowired
    private IGoodService goodService;
    @RequestMapping("/good")
    public String index() {
        List goodList = goodService.list();
        JSONArray jsonArray=  JSONArray.fromObject(goodList);
        return jsonArray.toString();
    }
}

訪問項目，能看到數據即爲環境搭建完成。