springboot系类代码：mybatis-spring-boot-starter-mysql-connector-java

Mybatis的功能架构三层：

• API接口层：提供给外部使用的接口API，开发人员通过这些本地API来操纵数据库。接口层一接收到调用请求就会调用数据处理层来完成具体的数据处理。
• 数据处理层：负责具体的SQL查找、SQL解析、SQL执行和执行结果映射处理等。它主要的目的是根据调用的请求完成一次数据库操作。
• 基础支撑层：负责最基础的功能支撑，包括连接管理、事务管理、配置加载和缓存处理，这些都是共用的东西，将他们抽取出来作为最基础的组件。为上层的数据处理层提供最基础的支撑。

package com.programb;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class MybatisAnnotationApplication {

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

package com.programb.controller;

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

import com.programb.mapper.UserMapper;
import com.programb.pojo.User;

import java.util.List;

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

    @SuppressWarnings("all")
    @Autowired
    UserMapper userMapper;

    @GetMapping("list")
    public List<User> list() {
        return userMapper.list();
    }

    @GetMapping("list/{username}")
    public List<User> listByUsername(@PathVariable("username") String username) {
        return userMapper.listByUsername(username);
    }

    @GetMapping("get/{username}/{password}")
    public User get(@PathVariable("username") String username, @PathVariable("password") String password) {
        return userMapper.get(username, password);
    }

    @GetMapping("get/bad/{username}/{password}")
    public User getBadUser(@PathVariable("username") String username, @PathVariable("password") String password) {
        return userMapper.getBadUser(username, password);
    }

}

package com.programb.mapper;

import org.apache.ibatis.annotations.*;
import com.programb.pojo.User;

import java.util.List;


@Mapper
public interface UserMapper {

    @Select("select * from t_user")
    @Results({
            @Result(property = "userId", column = "USER_ID"),
            @Result(property = "username", column = "USERNAME"),
            @Result(property = "password", column = "PASSWORD"),
            @Result(property = "mobileNum", column = "PHONE_NUM")
    })
    List<User> list();


    @SelectProvider(type = UserSqlProvider.class, method = "listByUsername")
    List<User> listByUsername(String username);


    @Results({
            @Result(property = "userId", column = "USER_ID"),
            @Result(property = "username", column = "USERNAME"),
            @Result(property = "password", column = "PASSWORD"),
            @Result(property = "mobileNum", column = "PHONE_NUM")
    })
    @Select("select * from t_user")
    List<User> listSample();

    @Select("select * from t_user where username like #{username} and password like #{password}")
    User get(@Param("username") String username, @Param("password") String password);

    @SelectProvider(type = UserSqlProvider.class, method = "getBadUser")
    User getBadUser(@Param("username") String username, @Param("password") String password);

}

package com.programb.mapper;

import com.fasterxml.jackson.databind.PropertyNamingStrategy;
import com.programb.pojo.User;
import org.apache.ibatis.annotations.Param;
import org.apache.ibatis.jdbc.SQL;
import java.lang.reflect.Field;


public class UserSqlProvider {
 
    public String listByUsername(String username) {
        return "select * from t_user where username =#{username}";
    }


    public String getBadUser(@Param("username") String username, @Param("password") String password) {
        return new SQL() {{
            SELECT("*");
            FROM("t_user");
            if (username != null && password != null) {
                WHERE("username like #{username} and password like #{password}");
            } else {
                WHERE("1=2");
            }
        }}.toString();
    }


    public static String getResultsStr(Class origin) {
        StringBuilder stringBuilder = new StringBuilder();
        stringBuilder.append("@Results({\n");
        for (Field field : origin.getDeclaredFields()) {
            String property = field.getName();
            //映射关系：对象属性(驼峰)->数据库字段(下划线)
            String column = new PropertyNamingStrategy.SnakeCaseStrategy().translate(field.getName()).toUpperCase();
            stringBuilder.append(String.format("@Result(property = \"%s\", column = \"%s\"),\n", property, column));
        }
        stringBuilder.append("})");
        return stringBuilder.toString();
    }


    public static void main(String[] args) {
        System.out.println(getResultsStr(User.class));
    }

}

package com.programb.pojo;

public class User {

    private String userId;
    private String username;
    private String password;
    private String mobileNum;

    public String getUserId() {
        return userId;
    }

    public void setUserId(String userId) {
        this.userId = userId;
    }

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getPassword() {
        return password;
    }

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

    public String getMobileNum() {
        return mobileNum;
    }

    public void setMobileNum(String mobileNum) {
        this.mobileNum = mobileNum;
    }
}

spring:
  datasource:

    url: jdbc:mysql://localhost:3306/socks?useSSL=false
    username: root
    password: root
    driver-class-name: com.mysql.jdbc.Driver

mybatis:
  configuration:

   map-underscore-to-camel-case: true

logging:
  level:

   com.hehe.mapper: debug

<?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>com.programb</groupId>
    <artifactId>springboot-mybatis-annotation</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>
    <name>spring-boot-mybatis-annotation</name>
    <description>SpringBoot</description>


    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.0.0.M5</version>
    </parent>

    <dependencies>
        <dependency> <!--添加Web依赖 -->
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency> <!--添加Mybatis依赖 -->
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>1.3.1</version>
        </dependency>
        <dependency><!--添加MySQL驱动依赖 -->
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency><!--添加Test依赖 -->
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>


    <repositories>
        <repository>
            <id>spring-snapshots</id>
            <url>http://repo.spring.io/snapshot</url>
            <snapshots>
                <enabled>true</enabled>
            </snapshots>
        </repository>
        <repository>
            <id>spring-milestones</id>
            <url>http://repo.spring.io/milestone</url>
        </repository>
    </repositories>
    <pluginRepositories>
        <pluginRepository>
            <id>spring-snapshots</id>
            <url>http://repo.spring.io/snapshot</url>
        </pluginRepository>
        <pluginRepository>
            <id>spring-milestones</id>
            <url>http://repo.spring.io/milestone</url>
        </pluginRepository>
    </pluginRepositories>


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