一、注解方式

1. pom

    <dependency>
        <groupId>org.mybatis.spring.boot</groupId>
        <artifactId>mybatis-spring-boot-starter</artifactId>
        <version>2.0.0</version>
    </dependency>
     <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
    </dependency>
    <!--lombok-->
    <dependency>
        <groupId>org.projectlombok</groupId>
        <artifactId>lombok</artifactId>
        <version>1.16.10</version>
    </dependency>

說明: springboot版本: 2.1.5.RELEASE

2. application.properties

# mysql
spring.datasource.url=jdbc:mysql://212.64.xxx.xxx:3306/test?autoR&useUnicode=true&characterEncoding=utf-8&allowMultiQueries=true
spring.datasource.username=xxx
spring.datasource.password=xxx
spring.datasource.driver-class-name=com.mysql.jdbc.Driver

3.在啟動類中添加對 mapper 包掃描@MapperScan

package com.wangzaiplus.test;

import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.Bean;
import org.springframework.web.cors.CorsConfiguration;
import org.springframework.web.cors.UrlBasedCorsConfigurationSource;
import org.springframework.web.filter.CorsFilter;

@SpringBootApplication
@MapperScan("com.wangzaiplus.test.mapper")
public class TestApplication {

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

    /**
     * 跨域
     * @return
     */
    @Bean
    public CorsFilter corsFilter() {
        final UrlBasedCorsConfigurationSource urlBasedCorsConfigurationSource = new UrlBasedCorsConfigurationSource();
        final CorsConfiguration corsConfiguration = new CorsConfiguration();
        corsConfiguration.setAllowCredentials(true);
        corsConfiguration.addAllowedOrigin("*");
        corsConfiguration.addAllowedHeader("*");
        corsConfiguration.addAllowedMethod("*");
        urlBasedCorsConfigurationSource.registerCorsConfiguration("/**", corsConfiguration);
        return new CorsFilter(urlBasedCorsConfigurationSource);
    }

}

說明: springboot項目添加corsFilter解決跨域問題

也可以直接在 Mapper 類上面添加注解@Mapper

4. mapper

package com.wangzaiplus.test.mapper;

import com.wangzaiplus.test.pojo.User;
import org.apache.ibatis.annotations.*;
import org.apache.ibatis.type.JdbcType;

import java.util.List;

public interface UserMapper {

    @Select("select * from user")
    @Results({
            @Result(property = "username", column = "username", jdbcType = JdbcType.VARCHAR),
            @Result(property = "password", column = "password")
    })
    List<User> selectAll();

    @Select("select * from user where id = #{id}")
    @Results({
            @Result(property = "username", column = "username", jdbcType = JdbcType.VARCHAR),
            @Result(property = "password", column = "password")
    })
    User selectOne(Integer id);

    @Insert("insert into user(username, password) values(#{username}, #{password})")
    void insert(User user);

    @Update("update user set username=#{username}, password=#{password} where id = #{id}")
    void update(User user);

    @Delete("delete from user where id = #{id}")
    void delete(Integer id);

}

5. controller

package com.wangzaiplus.test.controller;

import com.wangzaiplus.test.pojo.User;
import com.wangzaiplus.test.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;

import java.util.List;

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

    @Autowired
    private UserService userService;

    @GetMapping("users")
    public String getAll() {
        List<User> users = userService.getAll();
        return users.toString();
    }

    @GetMapping("{id}")
    public String getOne(@PathVariable Integer id) {
        User user = userService.getOne(id);
        return user + "";
    }

    @PostMapping
    public String add(User user) {
        userService.add(user);
        return "nice";
    }

    @PutMapping
    public String update(User user) {
        userService.update(user);
        return "nice";
    }

    @DeleteMapping("{id}")
    public String delete(@PathVariable Integer id) {
        userService.delete(id);
        return "nice";
    }

}

說明: restful接口風格

6. service

package com.wangzaiplus.test.service;

import com.wangzaiplus.test.pojo.User;

import java.util.List;

public interface UserService {

    List<User> getAll();

    User getOne(Integer id);

    void add(User user);

    void update(User user);

    void delete(Integer id);

}

7. impl

package com.wangzaiplus.test.service.impl;

import com.wangzaiplus.test.mapper.UserMapper;
import com.wangzaiplus.test.pojo.User;
import com.wangzaiplus.test.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.util.List;

@Service
public class UserServiceImpl implements UserService {

    @Autowired
    private UserMapper userMapper;

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

    @Override
    public User getOne(Integer id) {
        return userMapper.selectOne(id);
    }

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

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

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

}

說明: 僅供示例, 邏輯嚴謹性暫不考慮

8. pojo

package com.wangzaiplus.test.pojo;

import lombok.Data;

@Data
public class User {

    private Integer id;
    private String username;
    private String password;

}

說明: @Data lombok

9.sql

CREATE TABLE `user` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `username` varchar(100) COLLATE utf8mb4_unicode_ci NOT NULL DEFAULT '',
  `password` varchar(255) COLLATE utf8mb4_unicode_ci NOT NULL DEFAULT '',
  PRIMARY KEY (`id`),
  UNIQUE KEY `unq_username` (`username`)
) ENGINE=InnoDB AUTO_INCREMENT=2 DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci;

10. 接口請求

• add

image.png

image.png

• update

image.png

image.png

• delete

image.png

image.png

• getOne

image.png

• getAll

image.png

說明: 截圖請求參數(shù)id與數(shù)據(jù)庫id不對應(yīng)問題, 這是由于我接口文檔默認值設(shè)為1或2的, 請求成功后接口管理工具自動刷新顯示默認值id=1了, 所以看著好像不對, 實際沒問題

以上代碼均通過測試

二够挂、xml方式

1. pom文件<build>節(jié)點下添加

        <resources>
            <resource>
                <directory>src/main/java</directory>
                <includes>
                    <include>**/*.xml</include>
                </includes>
            </resource>
        </resources>

說明: 如果不添加此節(jié)點mybatis的mapper.xml文件都會被漏掉, 會出現(xiàn)org.apache.ibatis.binding.BindingException Invalid bound statement (not found)異常

2. mapper java

package com.wangzaiplus.test.mapper;

import com.wangzaiplus.test.pojo.User;

import java.util.List;

public interface UserMapper {

    List<User> selectAll();

    User selectOne(Integer id);

    void insert(User user);

    void update(User user);

    void delete(Integer id);

}

說明: 不需要@Select @Insert等注解了

3. 新建UserMapper.xml文件

<?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.wangzaiplus.test.mapper.UserMapper" >
    <resultMap id="BaseResultMap" type="com.wangzaiplus.test.pojo.User" >
        <id column="id" property="id" jdbcType="INTEGER" />
        <result column="username" property="username" jdbcType="VARCHAR" />
        <result column="password" property="password" jdbcType="VARCHAR" />
    </resultMap>

    <sql id="Base_Column_List" >
        id, username, password
    </sql>

    <select id="selectAll" resultMap="BaseResultMap">
        SELECT
        <include refid="Base_Column_List" />
        FROM user
    </select>

    <select id="selectOne" parameterType="int" resultMap="BaseResultMap">
        SELECT
        <include refid="Base_Column_List" />
        FROM user
        WHERE id = #{id}
    </select>

    <insert id="insert" parameterType="com.wangzaiplus.test.pojo.User">
        INSERT INTO user(username, password) VALUES (#{username}, #{password})
    </insert>

    <update id="update" parameterType="com.wangzaiplus.test.pojo.User">
        UPDATE user SET
        <if test="username != null">
            username = #{username},
        </if>
        <if test="password != null">
            password = #{password}
        </if>
        WHERE id = #{id}
    </update>

    <delete id="delete" parameterType="int">
        DELETE FROM user WHERE id =#{id}
    </delete>
</mapper>

說明: 相當于將上個版本@Select @Insert注解用xml配置文件形式代替而已

4. 其他都不需要修改

參考文章: https://www.cnblogs.com/ityouknow/p/6037431.html