springboot学习

yang嗯嗯要来充实自己了。
OK，那就从Springboot开始吧。

    
        org.springframework.boot
        spring-boot-starter-parent
        2.0.4.RELEASE
    

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

呐，环境已搭好。

@Controller
public class HelloController {

    @GetMapping("hello")
    @ResponseBody
    public String hello(){
        return "hello, spring boot";
    }
}

@RestController注解相当于@ResponseBody ＋ @Controller合在一起的作用。
现在来看连接池的java配置喽！

 
        
            org.springframework.boot
            spring-boot-starter-web
        
        
            com.alibaba
            druid
            1.1.0
        
    

再建一个jdbc.properties文件

jdbc.driverClassName=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://127.0.0.1:3306/eesy
jdbc.username=root
jdbc.password=12345678

@Configuration
@PropertySource("classpath:jdbc.properties")
public class JdbcConfig {
    @Value("${jdbc.url}")
    String url;
    @Value("${jdbc.driverClassName}")
    String driverClassName;
    @Value("${jdbc.username}")
    String username;
    @Value("${jdbc.password}")
    String password;
    @Bean
    public DataSource dataSource(){
        DruidDataSource dataSource = new DruidDataSource();
        dataSource.setDriverClassName(driverClassName);
        dataSource.setUrl(url);
        dataSource.setUsername(username);
        dataSource.setPassword(password);
        return dataSource;

    }
}

springboot属性注入

方式一

改名字：application.properties

 
            org.projectlombok
            lombok
 

@ConfigurationProperties(prefix = "jdbc")
@Data
public class JdbcProperties {
    String url;
    String driverClassName;
    String username;
    String password;
}

@Configuration
@EnableConfigurationProperties(JdbcProperties.class)
public class JdbcConfig {
    @Bean
    public DataSource dataSource(JdbcProperties prop){
        DruidDataSource dataSource = new DruidDataSource();
        dataSource.setDriverClassName(prop.getDriverClassName());
        dataSource.setUrl(prop.getUrl());
        dataSource.setUsername(prop.getUsername());
        dataSource.setPassword(prop.getPassword());
        return dataSource;

    }
}

方式二

@Data
public class JdbcProperties {
    String url;
    String driverClassName;
    String username;
    String password;
}

@Configuration
public class JdbcConfig {
    @Bean
    @ConfigurationProperties(prefix = "jdbc")
    public DataSource dataSource(){
        return new DruidDataSource();
    }
}

属性配置文件

yaml文件

jdbc:
  driverClassName: com.mysql.jdbc.Driver
  url: jdbc:mysql://127.0.0.1:3306/eesy
  username: root
  password: 12345678
  user:
    name: jack
    age: 21
    language:
      - java
      - php
      - ios

自动配置原理

yaml文件和properties两个文件都有取并集，若重名properties文件优先。

整合连接池

       
        
            org.springframework.boot
            spring-boot-starter-jdbc
        
        
        
            mysql
            mysql-connector-java
        

然后在application.yaml文件中配置数据库连接的四大参数

spring:
  datasource:
    driver-class-name: com.mysql.jdbc.Driver
    url: jdbc:mysql://127.0.0.1:3306/eesy
    username: root
    password: 12345678

整合mybatis

        
        
            org.mybatis.spring.boot
            mybatis-spring-boot-starter
            1.3.1
        

开启自动驼峰匹配

mybatis:
  configuration:
    map-underscore-to-camel-case: true

配置mapper文件所在位置（一般不用该配置，大多数情况下用的通用mapper）

mybatis:
  configuration:
    mapper-locations: mapper/*.xml

配置别名扫描包

mybatis:
  type-aliases-package: enen.pojo

mapper扫描器（接口）:通过添加@MapperScan注解

@SpringBootApplication
@MapperScan("enen.mapper")
public class BootDemoApplication {
    public static void main(String[] args) {
        SpringApplication.run(BootDemoApplication.class, args);
    }
}

附加通用mapper

https://github.com/abel533/Mapper

        
            tk.mybatis
            mapper-spring-boot-starter
            2.0.3
        

import tk.mybatis.mapper.common.Mapper;

public interface UserMapper extends Mapper {

}

一旦引入通用mapper，mybatis和jdbc连接池的依赖不需要，也会开启自动驼峰匹配。另外不能使用import org.mybatis.spring.annotation.MapperScan下的@MapperScan了，应该使用import tk.mybatis.spring.annotation.MapperScan;

maven依赖包

当数据库表名和实体名不一致时，在实体类上加入@Table注解，在主键加@Id，主键是自增长的加@KeySql，其他字段若不是都作为sql字段来用加@Transient

@Data
@Table(name="tb_user")
public class User {
    @Id
    @KeySql(useGeneratedKeys = true)
    private int id;
    private String username;
    private String password;
    private String name;
    private int age;
    private int sex;
    private Date birthday;
    @Transient
    private String note;
}

OK，接下来测试一下通用mapper
先引入test启动器

        
            org.springframework.boot
            spring-boot-starter-test
        

@RunWith(SpringRunner.class)
@SpringBootTest
public class UserMapperTest {
    @Autowired
    private UserMapper userMapper;
    @Test
    public void testQuery(){
        User user = userMapper.selectByPrimaryKey(2);
        System.out.println("user=" + user);
    }
}

写service

@Service
public class UserService {
    @Autowired
    private UserMapper userMapper;
    public User queryById(int id){
        return userMapper.selectByPrimaryKey(id);
    }
    public void insertUser(User user){
        userMapper.insert(user);
    }
}

写controller

@Slf4j
@Controller
@RequestMapping("user")
public class HelloController {
    @Autowired
    private UserService userService;
    @GetMapping("{id}")
    @ResponseBody
    public User hello(@PathVariable("id") int id){
        return userService.queryById(id);
    }
}

ok，撒花完结。