(二、下) springBoot 、maven 、mysql、 mybatis、 通用Mapper、lombok 简单搭建例子 《附项目源码》

接着上篇文章中 继续前进。

一、在maven 的pom.xm中添加组件依赖， mybatis通用Mapper，及分页插件

1、mybatis通用Mapper
<!-- mybatis通用Mapper-->
<dependency>
    <groupId>tk.mybatis</groupId>
    <artifactId>mapper-spring-boot-starter</artifactId>
    <version>2.0.3</version>
</dependency>
2、mybatis分页插件
<!-- 依赖地址：https://mvnrepository.com/artifact/com.github.pagehelper/pagehelper-spring-boot-starter -->
<dependency>
    <groupId>com.github.pagehelper</groupId>
    <artifactId>pagehelper-spring-boot-starter</artifactId>
    <version>1.2.7</version>
</dependency>

二、创建表：user：

SET NAMES utf8mb4;
SET FOREIGN_KEY_CHECKS = 0;

DROP TABLE IF EXISTS `user`;
CREATE TABLE `user`  (
  `id` varchar(50) CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL COMMENT '系统ID',
  `name` varchar(20) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL COMMENT '用户名',
  `age` int(4) NULL DEFAULT NULL COMMENT '年龄',
  `gender` varchar(4) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL COMMENT '性别 1 男 ，2女',
  PRIMARY KEY (`id`) USING BTREE
) ENGINE = InnoDB CHARACTER SET = utf8 COLLATE = utf8_general_ci ROW_FORMAT = Dynamic;

INSERT INTO `user` VALUES ('1', '路飞', 16, '1');
INSERT INTO `user` VALUES ('2', '罗罗诺亚索隆', 18, '1');
INSERT INTO `user` VALUES ('3', '娜美', 17, '2');

SET FOREIGN_KEY_CHECKS = 1;

三、再项目中创建 包结构，实体类，service, mapper, 等。

1、包结构及 用到的接口和类 如下：

2、各个需要改动的地方及 具体代码：

（1） application.yml 配置文件

#spring
spring:
  #mysql 数据源
  datasource:
    url: jdbc:mysql://127.0.0.1:3306/fish?zeroDateTimeBehavior=convertToNull&characterEncoding=utf8&characterSetResults=utf8&useSSL=false
    username: root
    password: etoak
    driver-class-name: com.mysql.jdbc.Driver

#mybatis
mybatis:
  mapperLocations: classpath:mapper/*.xml
  type-aliases-package: com.fish.winter.model
  configuration:
    map-underscore-to-camel-case: true

#Mybatis通用Mapper
mapper:
  mappers: com.fish.winter.base.BaseMapper
  not-empty: false
  identity: MYSQL
  before: true

#Mybatis分页插件pagehelper
pagehelper:
  helperDialect: mysql
  reasonable: false
  supportMethodsArguments: true
  params: count=countSql

（2）项目启动类  WinterApplication

package com.fish.winter;

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

@SpringBootApplication
@MapperScan(basePackages = "com.fish.winter.mapper") // 注意这里导入的 MapperScan 的包是：tk.mybatis.spring.annotation.MapperScan
public class WinterApplication {

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

（3）创建 通用Mapper 的通用 持久层接口：BaseMapper, 以便所有实体类的mapper  继承此接口，用来调用 通用Mapper 的各种方法。

package com.fish.winter.base;

import tk.mybatis.mapper.common.Mapper;
import tk.mybatis.mapper.common.MySqlMapper;

/**
 * @author 路飞
 * @date 2018-9-19
 * @description     持久化层的父类
 */
public interface BaseMapper<T> extends Mapper<T>, MySqlMapper<T>  { }

（4）创建实体类 User, 类中用到了 lombok 的 @Data 和 @Builder  注解

package com.fish.winter.model;

import lombok.Builder;
import lombok.Data;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.Table;

@Data
@Builder
@Table(name = "user")
public class User {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY, generator = "select uuid()")
    private String id;
    private String name;
    private Integer age;
    private String gender;

}

（5）在 controller 中添加 访问接口

package com.fish.winter.controller;

import com.fish.winter.model.User;
import com.fish.winter.service.UserService;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import javax.annotation.Resource;
import java.util.List;

@RestController
@RequestMapping("/test")
public class TestController {

    @RequestMapping("/hello")
    public String test() {
        return "你好spriongBoot";
    }

    @Resource
    private UserService userService;

    @RequestMapping("/user")
    private List<User> queryByExample() {
        return userService.list();
    }
}

（6）创建service ,及实现类

package com.fish.winter.service;

import com.fish.winter.model.User;
import java.util.List;

public interface UserService {
    // 获取user 信息
    List<User> list();
}

package com.fish.winter.serviceImpl;

import com.fish.winter.mapper.UserMapper;
import com.fish.winter.model.User;
import com.fish.winter.service.UserService;
import org.springframework.stereotype.Service;
import tk.mybatis.mapper.entity.Example;
import javax.annotation.Resource;
import java.util.List;

@Service("userService")
public class UserServiceImpl implements UserService {

    @Resource
    private UserMapper userMapper;

    @Override
    public List<User> list() {
        Example example = new Example(User.class);
        Example.Criteria criteria = example.createCriteria();
        criteria.andEqualTo("name", "路飞");
        List<User> userList = userMapper.selectByExample(example);
        return userList;
    }

}

（6）在浏览器中访问：http://127.0.0.1:8080/test/user ，结果如下。

项目源码地址：https://gitee.com/coderLOL/winter

==================================================================

有兴趣的朋可以自己研究下 Mybatis通用Mapper 的使用方法 ，下面是 文档地址：

https://gitee.com/free/Mapper/wikis/Home

https://github.com/abel533/Mapper/wiki