Spring boot Mybatis 整合

原创已于 2022-03-29 19:57:43 修改 · 158 阅读

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#springboot

于 2022-03-24 11:41:51 首次发布

本文档详细介绍了如何创建一个SpringBoot项目，并集成Mybatis-Plus进行数据库操作。从创建项目到编写DAO、Mapper、Service和Controller，每个步骤都清晰展示，包括数据库配置、实体类、Mapper接口和XML文件，最后展示了程序入口和运行方式。

步骤：
1.创建一个springboot项目：

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2.创建项目的文件结构以及jdk的版本

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3.选择项目所需要的依赖

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然后点击finish

5.看一下文件的结构：

6.查看一下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>2.6.4</version>
		<relativePath/> <!-- lookup parent from repository -->
	</parent>
	<groupId>com.example</groupId>
	<artifactId>anany</artifactId>
	<version>0.0.1-SNAPSHOT</version>
	<name>anany</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-devtools</artifactId>
			<scope>runtime</scope>
			<optional>true</optional>
		</dependency>-->
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-test</artifactId>
			<scope>test</scope>
		</dependency>
		<dependency>
			<groupId>org.mybatis.spring.boot</groupId>
			<artifactId>mybatis-spring-boot-starter</artifactId>
			<version>1.3.2</version>
		</dependency>
		<dependency>
			<groupId>mysql</groupId>
			<artifactId>mysql-connector-java</artifactId>
			<version>5.1.45</version>
		</dependency>

		<dependency>
			<groupId>com.baomidou</groupId>
			<artifactId>mybatis-plus</artifactId>
			<version>3.3.2</version>
		</dependency>
	</dependencies>

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

</project>

7.项目不使用application.properties文件而使用更加简洁的application.yml文件：
将原有的resource文件夹下的application.properties文件删除，
文件的内容如下：

spring.datasource.driver-class-name=com.mysql.jdbc.Driver
spring.datasource.username=root
spring.datasource.password=x5
spring.datasource.url=jdbc:mysql://127.0.0.1:3306/mybatis?useUnicode=true&characterEncoding=utf-8


mybatis.mapper-locations=classpath:mapper/*.xml

8.创建数据库：

9.创建controller：

package com.example.anany.controller;

import com.example.anany.entity.Student;
import com.example.anany.service.StudentService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.bind.annotation.RestController;

import java.util.List;

//@Controller    @RestController = @Controller + @ResponseBody
@RestController //springboot方法才可用，
public class StudentController {

    @Autowired
    StudentService ss;


    @RequestMapping("query")
    //public List<Student> query();
    //spring boot controller方法返回值可以自动转json，ssm框架不行
    public List<Student> query(Student student,Integer pageNo){
        List<Student> students = ss.query(student,pageNo);
        //System.out.println(students);
        return students;
    }

    @RequestMapping("add")
    //public void add(Student student);
    public String add(Student student){
        ss.add(student);
        return "1";
    }

    @RequestMapping("update")
    //public void update(Student student);
    public void update(Student student){
        ss.update(student);
    }

    @RequestMapping("queryById")
    //public Student queryById(Integer id);
    public Student queryById(Integer id){
        Student student = ss.queryById(id);
        System.out.println(student);
        return student;
    }

    @RequestMapping("delete")
    //public void delete(Integer id);
    public void delete(Integer id){
        ss.delete(id);
    }


}

9.创建service：

package com.example.anany.service;

import com.example.anany.entity.Student;

import java.util.List;

public interface StudentService {

    public List<Student> query(Student student,Integer pageNo);

    public void add(Student student);

    public void update(Student student);


    public Student queryById(Integer id);


    public void delete(Integer id);
}

9.创建service.impl：

package com.example.anany.service.impl;

import com.example.anany.dao.StudentDao;
import com.example.anany.entity.Student;
import com.example.anany.service.StudentService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.util.List;

@Service
public class StudentServiceImpl implements StudentService {

    @Autowired
    StudentDao dao;

    @Override
    public List<Student> query(Student student,Integer pageNo) {
        return dao.query(student,pageNo);
    }

    @Override
    public void add(Student student) {
        dao.add(student);
    }

    @Override
    public void update(Student student) {
        dao.update(student);
    }

    @Override
    public Student queryById(Integer id) {
        Student student = dao.queryById(id);
        return student;
    }

    @Override
    public void delete(Integer id) {
        dao.delete(id);
    }


}

10.创建dao/mapper：

package com.example.anany.dao;

import com.example.anany.entity.Student;
import org.apache.ibatis.annotations.Param;

import java.util.List;

public interface StudentDao {
    public List<Student> query(@Param("student") Student student, @Param("pageNo") Integer pageNo);

    public void add(Student student);

    public void update(Student student);

    public Student queryById(Integer id);

    public void delete(Integer id);
}

11.创建dao/mapper.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.anany.dao.StudentDao">
    <!--表单显示-->
    <select id="query" resultType="com.example.anany.entity.Student">
        select id,name,email,age from student1
        <where>
            <if test="student.name !=null and student.name != ''">
                and name=#{student.name}
            </if>
            <if test="student.email != null and student.email != ''">
                and email=#{student.email}
            </if>
        </where>
        <if test="pageNo != null and pageNo != ''">
            limit 0,#{pageNo}
        </if>
    </select>
    <insert id="add">
        insert into student1(name,email,age) values (#{name},#{email},#{age})
    </insert>
    <update id="update">
        update student1 set name=#{name},email=#{email},age=#{age} where id=#{id}
    </update>
    <select id="queryById" resultType="com.example.anany.entity.Student">
        select id,name,email,age from student1 where id=#{id}
    </select>
    <delete id="delete">
        delete from student1 where id=#{id}
    </delete>

</mapper>

12.程序入口，创建项目的时候系统自动创建的：

package com.example.anany;

import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
//不用写配置文件了，直接用这个注解，就可以找到dao层的位置了
@MapperScan({"com.example.anany.dao"})
public class AnanyApplication {

	public static void main(String[] args) {
		SpringApplication.run(AnanyApplication.class, args);
	}

}

13.在运行的时候我们只需要在浏览器中输入地址即可