Spring Boot - 3. 集成 mybatis

0. 创建数据库表

CREATE TABLE `employees` (
  `userName` varchar(10) DEFAULT NULL,
  `password` varchar(100) DEFAULT NULL,
  `id` int(20) NOT NULL AUTO_INCREMENT,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

1. 配置 maven

1. 添加 mysql 数据库驱动的依赖；

<!-- mysql 数据库驱动 -->
<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <scope>runtime</scope>
</dependency>

2. 添加 spring boot mybatis 的依赖；

<!-- spring boot mybatis 依赖：注意1.0.0版本还不支持拦截器插件 -->
<dependency>
    <groupId>org.mybatis.spring.boot</groupId>
    <artifactId>mybatis-spring-boot-starter</artifactId>
    <version>1.3.1</version>
</dependency>

2. 配置数据库

1. 在 application.properties 文件中添加数据库连接配置代码；

# 设置数据库
spring.datasource.url=jdbc:mysql://域名:端口号/数据库名称?characterEncoding=UTF-8
spring.datasource.username=用户名
spring.datasource.password=密码
spring.datasource.driverClassName=com.mysql.jdbc.Driver
spring.datasource.max-active=20
spring.datasource.max-idle=8
spring.datasource.min-idle=8
spring.datasource.initial-size=10

3. 添加 mapper 的扫描注解

1. 在 Main class 添加注解；

package com.mm.spring.demo;

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

@SpringBootApplication
@MapperScan("com.mm.spring.demo.mapper") // 扫描该包下相应的class，主要是 mybatis 的持久化类
public class DemoApplication {
    public static void main(String[] args) {
        SpringApplication.run(DemoApplication.class, args);
    }
}

4. 创建实体类

package com.mm.spring.demo.bean;

public class Employees {

    private Integer id;
    private String userName;
    private String password;

    // 此处省略了 getter / setter 方法
}

5. 创建 Mapper 接口

package com.mm.spring.demo.mapper;

import com.mm.spring.demo.bean.Employees;
import org.apache.ibatis.annotations.Select;
import java.util.List;

public interface EmployeesMapper {

    @Select("select * from employees where userName = #{name}")
     List<Employees> likeName(String name);

    @Select("select * from employees where id = #{id}")
    Employees getById(int id);

    @Select("select name from employees where id = #{id}")
    String getNameById(int id);
}

6. 创建 Service 类

package com.mm.spring.demo.service;

import com.mm.spring.demo.bean.Employees;
import com.mm.spring.demo.mapper.EmployeesMapper;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import java.util.List;

@Service
public class EmployeesService {

    @Autowired
    private EmployeesMapper employeesMapper;

    public List<Employees> likeName(String name){
        return employeesMapper.likeName(name);
    }

    public  Employees getById(int id){
        return employeesMapper.getById(id);
    }

    public String getNameById(int id){
        return employeesMapper.getNameById(id);
    }
}

7. 创建 Controller 类

package com.mm.spring.demo.controller;

import com.mm.spring.demo.bean.Employees;
import com.mm.spring.demo.service.EmployeesService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;
import java.util.List;

@RestController
public class EmployeesController {

    @Autowired
    private EmployeesService employeesService;

    @GetMapping("/likeName")
    public List<Employees> likeName(String name){
        return employeesService.likeName(name);
    }
}

8. 测试接口

1. 在 Chrome 中输入 GET 请求 http://localhost:8080/likeName?name=test；

2. 得到如图的结果：

   
   屏幕快照 2018-01-17 15.34.28.png

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9. 添加分页功能

1. maven 依赖；

<!-- MyBatis提供了拦截器接口，我们可以自己实现拦截器
 https://mvnrepository.com/artifact/com.github.pagehelper/pagehelper -->
<dependency>
    <groupId>com.github.pagehelper</groupId>
    <artifactId>pagehelper</artifactId>
    <version>4.2.1</version>
</dependency>

2. 加入配置文件

package com.mm.spring.demo.config;

import com.github.pagehelper.PageHelper;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import java.util.Properties;

@Configuration
public class MyBatisConfiguration {

    @Bean
    public PageHelper pageHelper(){
        PageHelper pageHelper = new PageHelper();

        Properties properties = new Properties();
        properties.setProperty("offsetAsPageNum","true");
        properties.setProperty("rowBoundsWithCount","true");
        properties.setProperty("reasonable","true");
        properties.setProperty("dialect", "mysql");

        pageHelper.setProperties(properties);

        return pageHelper;
    }
}

3. 使用：在 Controller 中调用静态方法：

import com.github.pagehelper.PageHelper;

@GetMapping("/likeName")
public List<Employees> likeName(String name, Integer pageNum) {
    pageNum = (null == pageNum || pageNum <= 0) ? 1 : pageNum;
    // 参数1：pageNum  参数2：pageSize
    PageHelper.startPage(pageNum, 2);
    return employeesService.likeName(name);
}

---

10. 插入数据

1. 在 EmployeesMapper 加入抽象方法；

// 插入数据
@Insert("insert into employees (userName) values(#{userName})")
// 设置主键自增
@Options(keyProperty = "id", keyColumn = "id", useGeneratedKeys = true)
void save(Employees employees);

2. 在 EmployeesService 添加事物；

import org.springframework.transaction.annotation.Transactional;

@Transactional // 添加事物
public void save(Employees employees) {
    employeesMapper.save(employees);
}

3. 在 EmployeesController 添加代码；

@GetMapping("/save")
public Employees save() {
    Employees employees = new Employees();
    employees.setUserName("张三");
    employeesService.save(employees);
    return  employees;
}

4. 访问 http://localhost:8080/save ；
   屏幕快照 2018-01-17 18.12.54.png