创建用户表

CREATE TABLE users(
	uid int(10) PRIMARY KEY AUTO_INCREMENT COMMENT '用户id',
	uname VARCHAR(255) COMMENT '用户姓名',
	pwd VARCHAR(255) COMMENT '用户密码',
	sex int(1) COMMENT '用户性别，1：男，0：女',
	age int(3) COMMENT '用户年龄'
);

新增用户数据

INSERT INTO users VALUES(1,"张三","zs",1,21);
INSERT INTO users VALUES(2,"李四","ls",0,18);
INSERT INTO users VALUES(3,"王五","ww",0,20);
INSERT INTO users VALUES(4,"赵六","zl",1,26);
INSERT INTO users VALUES(5,"十七","sq",0,22);
INSERT INTO users VALUES(6,"阿什","as",1,25);

Navicat显示结果

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在IDEA中创建SpringBoot项目

在这里插入图片描述

在pom.xml中引入jar包坐标

<parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>2.1.9.RELEASE</version>
    <relativePath/>
</parent>

<dependencies>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-jdbc</artifactId>
    </dependency>
    <!--springmvc的启动器-->
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
    <!--mybatis框架的启动器-->
    <dependency>
        <groupId>org.mybatis.spring.boot</groupId>
        <artifactId>mybatis-spring-boot-starter</artifactId>
        <version>2.1.1</version>
    </dependency>
    <!--SpringBoot热部署的jar包-->
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-devtools</artifactId>
        <scope>runtime</scope>
        <optional>true</optional>
    </dependency>
    <!--mysql驱动的jar包-->
    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <scope>runtime</scope>
    </dependency>
    <!--简化javabean代码的插件-->
    <dependency>
        <groupId>org.projectlombok</groupId>
        <artifactId>lombok</artifactId>
        <optional>true</optional>
    </dependency>
    <!--通用mapper启动器-->
    <dependency>
        <groupId>tk.mybatis</groupId>
        <artifactId>mapper-spring-boot-starter</artifactId>
        <version>2.1.5</version>
    </dependency>
</dependencies>

application.yaml介绍及配置

application.yaml是SpringBoot项目的配置文件，在其中配置的内容会覆盖启动器中的默认配置。

#端口号
server:
  port: 8888
#数据源配置
spring:
  datasource:
    url: jdbc:mysql://localhost:3306/test?serverTimezone=GMT
    username: root
    password: root
#mybatis配置
mybatis:
  #mapper.xml所在位置
#  mapper-locations: classpath:mapper/*Mapper.xml
  #别名配置
#  type-aliases-package: cn.xxxq.user_service.pojo

创建用户实体类

Lombok中的注解
	@Getter：生成get方法的注解
	@Setter：生成set方法的注解
	@ToString：生成toString方法的注解

package cn.xxxq.user_service.pojo;

import lombok.Getter;
import lombok.Setter;
import lombok.ToString;

@Getter
@Setter
@ToString
public class User {
    private Integer uid;
    private String uname;
    private String pwd;
    private Integer sex;
    private Integer age;
}

创建UserMapper

在通用Mapper中，已经帮我们解决了单表的增删改查操作。所以我们只需要让UserMapper
继承tk.mybatis.mapper.common.Mapper接口即可，一般单表的增删改查就不用写SQL语句了。

package cn.xxxq.user_service.mapper;

import cn.xxxq.user_service.pojo.User;
import tk.mybatis.mapper.common.Mapper;

public interface UserMapper extends Mapper<User> {

}

创建UserService接口

package cn.xxxq.user_service.service;

import cn.xxxq.user_service.pojo.User;
import java.util.List;

public interface UserService {

    /*查询所有用户*/
    List<User> queryAllUser();

    /*根据用户id查询用户*/
    User queryUserByUid(Integer uid);

    /*根据用户id修改用户信息*/
    void updateUserByUid(User user);

    /*添加用户*/
    void addUser(User user);

    /*根据用户id删除用户*/
    void deleteUserByUids(Integer[] uids);
    
}

创建UserService实现类

@service：创建实现类对象并将之添加到Spring Bean容器中。
@Transactional：开启声明式事务注解，为该类添加事务支持。
@@Autowired：注入Spring Bean容器中指定的对象。

package cn.xxxq.user_service.service;

import cn.xxxq.user_service.mapper.UserMapper;
import cn.xxxq.user_service.pojo.User;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import java.util.List;
import java.util.stream.Stream;

@Service
@Transactional
public class UserServiceImpl implements UserService{

    @Autowired
    private UserMapper userMapper;

    @Override
    public List<User> queryAllUser() {
        return userMapper.selectAll();
    }

    @Override
    public User queryUserByUid(Integer uid) {
        return userMapper.selectByPrimaryKey(uid);
    }

    @Override
    public void updateUserByUid(User user) {
        userMapper.updateByPrimaryKeySelective(user);
    }

    @Override
    public void addUser(User user) {
        userMapper.insertSelective(user);
    }

    /*根据用户id删除用户*/
    @Override
    public void deleteUserByUids(Integer[] uids) {
        /*Stream流+方法引用+lambda表达式简化删除代码*/
        Stream.of(uids).forEach(userMapper::deleteByPrimaryKey);
    }
}

创建Controller

package cn.xxxq.user_service.controller;

import cn.xxxq.user_service.pojo.User;
import cn.xxxq.user_service.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import java.util.List;

@RestController
@RequestMapping("/user")
public class UserController {

    @Autowired
    private UserService userService;

    /*查询所有用户*/
    @RequestMapping("/queryAllUser")
    public List<User> queryAllUser() {
        return userService.queryAllUser();
    }

    /*根据用户id查询用户*/
    @RequestMapping("/queryUserByUid/{uid}")
    public User queryUserByUid(@PathVariable("uid") Integer uid) {
        return userService.queryUserByUid(uid);
    }

   /*根据用户id修改用户信息*/
    @RequestMapping("/updateUserByUid")
    public void updateUserByUid(User user) {
        userService.updateUserByUid(user);
    }

    /*添加用户*/
    @RequestMapping("/addUser")
    public void addUser(User user) {
        userService.addUser(user);
    }

    /*根据用户id删除用户*/
    @RequestMapping("/deleteUserByUids")
    public void deleteUserByUids(Integer[] uids) {
        userService.deleteUserByUids(uids);
    }
}

修改SpringBoot项目启动类

@MapperScan(basePackages = "cn.xxxq.user_service.mapper")：扫描Mapper接口所在包

package cn.xxxq.user_service;

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

@SpringBootApplication
@MapperScan(basePackages = "cn.xxxq.user_service.mapper")
public class UserServiceApplication {

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

}