Spring Boot（三）： 集成Mybatis和Druid实现增删改查

版权声明：本文为博主原创文章，转载请附上链接。 https://blog.csdn.net/qq_36182135/article/details/81513380

查了很多教程和博客，基本都是把Spring Boot和Spring Data JPA放在一起用，个人用不惯JPA，所以直接Mybatis了，毕竟现在大部分人用的都是Mybatis，这章主要是写一个基础表的增删改查

首先搭建一个Spring Boot项目，项目结构和启动类如下

然后是pom.xml引入我们需要的包

<?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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
	<modelVersion>4.0.0</modelVersion>

	<groupId>pers.hong</groupId>
	<artifactId>demo</artifactId>
	<version>0.0.1-SNAPSHOT</version>
	<packaging>jar</packaging>

	<name>demo</name>
	<description>Demo project for Spring Boot</description>

	<parent>
		<groupId>org.springframework.boot</groupId>
		<artifactId>spring-boot-starter-parent</artifactId>
		<version>2.0.4.RELEASE</version>
		<relativePath/> <!-- lookup parent from repository -->
	</parent>

	<properties>
		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
		<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
		<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>
		</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>1.3.1</version>
		</dependency>
		<!--mybatis的分页插件-->
		<dependency>
			<groupId>com.github.pagehelper</groupId>
			<artifactId>pagehelper-spring-boot-starter</artifactId>
			<version>1.2.3</version>
		</dependency>
		<!--mysql连接-->
		<dependency>
			<groupId>mysql</groupId>
			<artifactId>mysql-connector-java</artifactId>
			<version>5.1.38</version>
		</dependency>
		<!--druid包-->
		<dependency>
			<groupId>com.alibaba</groupId>
			<artifactId>druid-spring-boot-starter</artifactId>
			<version>1.1.9</version>
		</dependency>
		<!--lang工具包-->
		<dependency>
			<groupId>org.apache.commons</groupId>
			<artifactId>commons-lang3</artifactId>
			<version>3.6</version>
		</dependency>
	</dependencies>

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

 数据库字段也很简单，主键设为自增

然后新建实体类User，同时生成两个构造器和toString方法

package pers.hong.demo.entity;

/**
 * @Description:
 * @Auther: hong
 * @Date: 2018/8/9/009 16:22
 */
public class User {
    private Integer id;
    private String name;
    private String password;
    private String email;

     public Integer getId() {
        return id;
    }

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

    public String getName() {
        return name;
    }

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

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    public String getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email;
    }

    public User(Integer id, String name, String password, String email) {
        this.id = id;
        this.name = name;
        this.password = password;
        this.email = email;
    }

    public User() {
    }

    @Override
    public String toString() {
        return "User{" +
                "id=" + id +
                ", name='" + name + '\'' +
                ", password='" + password + '\'' +
                ", email='" + email + '\'' +
                '}';
    }
}

接下来写Dao层的代码，在写Dao层代码前，要先对yml文件进行配置

上面被注释掉的是不使用Druid连接池时的连接数据库的写法，下面除了原先的数据库配置，还有Druid的各项配置，包括最大最小连接数等（官方文档写的十分详细，这里就不细说了），然后是mybatis的配置，mapper-Location是存放mybatis的xml文件的路径，config-Location是mybatis配置文件的路径，type-aliases-package是指别名对应的实体类，配置了这个在config文件里就可以不用配置别名了，默认是小写，比如实体类User，别名就是user

mybatis的配置文件如下，配置了数据类型的别名

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN" "http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
    <typeAliases>
        <typeAlias type="java.lang.Integer" alias="Integer" />
        <typeAlias type="java.lang.Long" alias="Long"  />
        <typeAlias alias="HashMap" type="java.util.HashMap" />
        <typeAlias alias="LinkedHashMap" type="java.util.LinkedHashMap" />
        <typeAlias alias="ArrayList" type="java.util.ArrayList" />
        <typeAlias alias="LinkedList" type="java.util.LinkedList" />
    </typeAliases>
</configuration>

然后是Mapper接口和xml文件，增删改查基础方法

@Mapper
public interface UserMapper {
    List<User> getUserById(@Param("id") Integer id);
    List<User> getAllUser();
    void updateUserEmailById(@Param("id") Integer id);
    void deleteUserById(@Param("id") Integer id);
    void insertUser(User user);
}

<?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="pers.hong.demo.mapper.UserMapper">
    <resultMap id="BaseMap" type="user">
        <id column="id" property="id" jdbcType="BIGINT"/>
        <result column="name" property="name" jdbcType="VARCHAR"/>
        <result column="password" property="password" jdbcType="VARCHAR"/>
        <result column="email" property="email" jdbcType="VARCHAR"/>
    </resultMap>
    <sql id="BaseColumn">
        id,name,password,email
    </sql>
    <insert id="insertUser" parameterType="user">
        INSERT INTO t_user
        (name,password,email)
        VALUE
        (#{name},#{password},#{email})
    </insert>
    <update id="updateUserEmailById" parameterType="Integer">
        UPDATE t_user
        SET
        <if test="name != null ">name = #{name}</if>
        <if test="password != null">password = #{password}</if>
        email = #{email}
    </update>
    <delete id="deleteUserById" parameterType="Integer">
        DELETE FROM t_user
        WHERE id = #{id}
    </delete>
    <select id="getUserById" resultMap="BaseMap" parameterType="Integer">
        SELECT
        <include refid="BaseColumn"/>
        FROM t_user
        WHERE id = #{id}
    </select>
    <select id="getAllUser" resultMap="BaseMap">
        SELECT
        <include refid="BaseColumn"/>
        FROM t_user
    </select>

</mapper>

然后是service和实现层的代码，其实这一步没什么太大必要，因为demo没有做什么业务操作，但是为了后面对项目进行扩展，就先写着了

public interface UserService {
    List<User> getAllUsers();
    List<User> getUserById(@Param("id") Integer id);
    void updateUserEmailById(@Param("id") Integer id);
    void deleteUserById(@Param("id") Integer id);
    void insertUser(User user);
}

----------------------------------------------------------

@Service
public class UserServiceImpl implements UserService {
    @Autowired
    private UserMapper userMapper;

    @Override
    public List<User> getAllUsers() {
        return userMapper.getAllUser();
    }

    @Override
    public List<User> getUserById(Integer id) {
        return userMapper.getUserById(id);
    }

    @Override
    public void updateUserEmailById(Integer id) {
        userMapper.updateUserEmailById(id);
    }

    @Override
    public void deleteUserById(Integer id) {
        userMapper.deleteUserById(id);
    }

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

最后是controller层

package pers.hong.demo.controller;

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.RequestMethod;
import org.springframework.web.bind.annotation.RestController;
import pers.hong.demo.entity.User;
import pers.hong.demo.service.UserService;

import java.util.ArrayList;
import java.util.List;

/**
 * @Description:
 * @Auther: hong
 * @Date: 2018/8/9/009 17:03
 */
@RestController
public class UserController {
    @Autowired
    private UserService userService;

    @RequestMapping(value = "/getAllUser",method = RequestMethod.GET)
    public List<User> getAllUser(){
        List<User> resultList = new ArrayList<>();
        resultList = userService.getAllUsers();
        return resultList;
    }

    @RequestMapping(value = "/getUserById/{id}",method = RequestMethod.GET)
    public List<User> getUser(@PathVariable Integer id){
        List<User> resultList = new ArrayList<>();
        resultList = userService.getUserById(id);
        return resultList;
    }

    @RequestMapping(value = "/updateUserById")
    public void updateUser(@PathVariable Integer id){
        userService.updateUserEmailById(id);
    }

    @RequestMapping(value = "/deleteUserById/{id}")
    public void deleteUser(@PathVariable Integer id){
        userService.deleteUserById(id);
    }

    @RequestMapping(value = "/insertUser")
    public void insertUser(User user){
        userService.insertUser(new User(null,"qqq","qqq","qqq"));
    }
}

基本增删改查就完成了，让我们在浏览器中测试一下

下一章用Vue写下界面，不然修改删除都不好测OAO