1.引入依赖

可以在创建springboot引用的时候选择好需要开发的模块

 也可以直接在pom文件添加依赖

<?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>
    <groupId>com.example</groupId>
    <artifactId>springboot-data</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>springboot-data</name>
    <description>springboot-data</description>

    <properties>
        <java.version>1.8</java.version>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <spring-boot.version>2.3.7.RELEASE</spring-boot.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>2.1.3</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jdbc</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-jdbc</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
        </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>junit</groupId>
            <artifactId>junit</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-dependencies</artifactId>
                <version>${spring-boot.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>

    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.8.1</version>
                <configuration>
                    <source>1.8</source>
                    <target>1.8</target>
                    <encoding>UTF-8</encoding>
                </configuration>
            </plugin>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <version>2.3.7.RELEASE</version>
                <configuration>
                    <mainClass>com.example.springbootdata.SpringbootDataApplication</mainClass>
                </configuration>
                <executions>
                    <execution>
                        <id>repackage</id>
                        <goals>
                            <goal>repackage</goal>
                        </goals>
                    </execution>
                </executions>
            </plugin>
        </plugins>
    </build>

</project>

2.准备数据库

数据库建表语句

这里我仅仅用到topic一张表 

配置数据库连接池注意如果mysql数据库在8.0+的要在drive加cj

# 应用名称
spring.application.name=springboot-data
# 数据库驱动：
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
# 数据源名称
spring.datasource.name=defaultDataSource
# 数据库连接地址
spring.datasource.url=jdbc:mysql://localhost:3306/newsmanagersystem?useUnicode=true&characterEncoding=UTF-8&serverTimezone=UTC
# 数据库用户名&密码：
spring.datasource.username=root
spring.datasource.password=123456
# 应用服务 WEB 访问端口
server.port=8080

3.创建实体类Topic

package com.example.springbootdata.bean;

public class Topic {
    private Integer tid;
    private String tname;

    public Integer getTid() {
        return tid;
    }

    public void setTid(Integer tid) {
        this.tid = tid;
    }

    public String getTname() {
        return tname;
    }

    public void setTname(String tname) {
        this.tname = tname;
    }
}

 4.创建mapper层，对数据库进行操作

package com.example.springbootdata.mapper;

import com.example.springbootdata.bean.Topic;
import org.apache.ibatis.annotations.*;

//@Mapper
public interface TopicMapper {
    @Select("select * from topic where tid=#{id}")
    public Topic gettopicById(Integer id);

    @Delete("delete from topic where tid=#{id}")
    public  int delete(Integer id);

    @Insert("insert into topic(tname) values(#{tname})")
    public int insertTopic(Topic topic);

    @Update("update topic set tname=#{tname} where tid=#{tid}")
    public void updateTopic(Topic topic);
}

这次我们用的方式是直接在方法上通过注解sql语句的方式进行操作，因为id是自增所以只需要插入tname的值就可以了

除了在每个接口类中加上@Mapper

也可以在主类上添加包扫描这样在mapper所有的接口类都会等同于加上了@Mapper注解

@MapperScan(value = "com.example.springbootdata.mapper")

注意！

sql语句中inset update delete是不需要返回值类型的，

将mapper中这些方法的返回值类型设为int或void。

但是也不要忘记接口和实现类的返回类型也要改

5.创建控制层

实现我们在网页进行操作修改数据库（这里我们简单写）

package com.example.springbootdata.controller;

import com.example.springbootdata.bean.Topic;
import com.example.springbootdata.mapper.TopicMapper;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;

import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class TopicController {
    @Autowired
    TopicMapper topicMapper;

    @GetMapping("/intopic")
    public Topic inserDept(Topic topic){
        topicMapper.insertTopic(topic);
        return  topic;
    }
    @GetMapping("/delete")
    public void delete(Integer id){
        topicMapper.delete(id);

    }
    @GetMapping("/gettopicById")
    public Topic gettopicById(Integer id){
        Topic tp;
        tp=topicMapper.gettopicById(id);
        return tp;
    }

    @GetMapping("/updateTopic")
    public void updateTopic(Topic topic){
        topicMapper.updateTopic(topic);

    }
}

我们要注入TopicMapper 才能引入方法

6.测试

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