SpringBoot与数据访问
1. JDBC
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-jdbc</artifactId>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<scope>runtime</scope>
</dependency>
spring:
datasource:
username: root
password: 123456
url: jdbc:mysql://192.168.15.22:3306/jdbc
driver-class-name: com.mysql.cj.jdbc.Driver
效果：
默认是用com.zaxxer.hikari.HikariDataSource作为数据源；
数据源的相关配置都在DataSourceProperties里面；
@ConfigurationProperties(prefix = "spring.datasource")
public class DataSourceProperties implements BeanClassLoaderAware, InitializingBean {
自动配置原理：
org.springframework.boot.autoconfigure.jdbc：
-
参考DataSourceConfiguration，根据配置创建数据源，默认使用
HikariDataSource；可以使用spring.datasource.type指定自定义的数据源类型； -
SpringBoot默认可以支持；
org.apache.tomcat.jdbc.pool.DataSource
com.zaxxer.hikari.HikariDataSource
org.apache.commons.dbcp2.BasicDataSource
- 自定义数据源类型
/**
* Generic DataSource configuration.
*/
@Configuration(proxyBeanMethods = false)
@ConditionalOnMissingBean(DataSource.class)
@ConditionalOnProperty(name = "spring.datasource.type")
static class Generic {
@Bean
DataSource dataSource(DataSourceProperties properties) {
//使用DataSourceBuilder创建数据源，利用反射创建相应type的DataSource，并绑定相关属性
return properties.initializeDataSourceBuilder().build();
}
}
- 操作数据库：自动配置了JdbcTemplate操作数据库
@Controller
public class HelloController {
@Autowired
JdbcTemplate jdbcTemplate;
@ResponseBody
@GetMapping("/query")
public Map<String,Object> map(){
List<Map<String, Object>> list = jdbcTemplate.queryForList("select * FROM department");
return list.get(0);
}
}
2. 整合Druid数据源
导入druid数据源
@Configuration
public class DruidConfig {
@ConfigurationProperties(prefix = "spring.datasource")
@Bean
public DataSource druid() {
return new DruidDataSource();
}
//配置Druid的监控
//1、配置一个管理后台的Servlet
@Bean
public ServletRegistrationBean<StatViewServlet> statViewServlet() {
ServletRegistrationBean<StatViewServlet> bean = new ServletRegistrationBean<StatViewServlet>(
new StatViewServlet(), "/druid/*");
Map<String, String> initParams = new HashMap<>();
initParams.put("loginUsername", "admin");
initParams.put("loginPassword", "123456");
initParams.put("allow", "");//默认就是允许所有访问
initParams.put("deny", "192.168.2.2");
bean.setInitParameters(initParams);
return bean;
}
//2、配置一个web监控的filter
@Bean
public FilterRegistrationBean<WebStatFilter> webStatFilter() {
FilterRegistrationBean<WebStatFilter> bean = new FilterRegistrationBean<WebStatFilter>();
bean.setFilter(new WebStatFilter());
Map<String, String> initParams = new HashMap<>();
initParams.put("exclusions", "*.js,*.css,/druid/*");
bean.setInitParameters(initParams);
bean.setUrlPatterns(Arrays.asList("/*"));
return bean;
}
}
数据源配置文件
spring:
datasource:
username: root
password: 123456
url: jdbc:mysql://192.168.2.2:3307/jdbc
driver-class-name: com.mysql.cj.jdbc.Driver
type: com.alibaba.druid.pool.DruidDataSource
# 数据源其他配置
initialSize: 5
minIdle: 5
maxActive: 20
maxWait: 60000
timeBetweenEvictionRunsMillis: 60000
minEvictableIdleTimeMillis: 300000
validationQuery: SELECT 1 FROM DUAL
testWhileIdle: true
testOnBorrow: false
testOnReturn: false
poolPreparedStatements: true
# 配置监控统计拦截的filters，去掉后监控界面sql无法统计，'wall'用于防火墙
filters: stat,wall,log4j
maxPoolPreparedStatementPerConnectionSize: 20
useGlobalDataSourceStat: true
connectionProperties: druid.stat.mergeSql=true;druid.stat.slowSqlMillis=500
3. 整合MyBatis
<dependency>
<groupId>org.mybatis.spring.boot</groupId>
<artifactId>mybatis-spring-boot-starter</artifactId>
<version>2.1.2</version>
</dependency>
步骤：
1）、配置数据源相关属性（见上一节Druid）
2）、给数据库建表
3）、创建JavaBean
4）注解版
//指定这是一个操作数据库的mapper
@Mapper
public interface DepartmentMapper {
@Select("select * from department where id=#{id}")
public Department getDeptById(Integer id);
@Delete("delete from department where id=#{id}")
public int deleteDeptById(Integer id);
@Options(useGeneratedKeys = true,keyProperty = "id")
@Insert("insert into department(departmentName) values(#{departmentName})")
public int insertDept(Department department);
@Update("update department set departmentName=#{departmentName} where id=#{id}")
public int updateDept(Department department);
}
问题：
自定义MyBatis的配置规则；给容器中添加一个ConfigurationCustomizer；
@org.springframework.context.annotation.Configuration
public class MyBatisConfig {
@Bean
public ConfigurationCustomizer configurationCustomizer(){
return new ConfigurationCustomizer(){
@Override
public void customize(Configuration configuration) {
configuration.setMapUnderscoreToCamelCase(true);
}
};
}
}
使用MapperScan批量扫描所有的Mapper接口；
@MapperScan(value = "com.atguigu.springboot.mapper")
@SpringBootApplication
public class SpringBoot06DataMybatisApplication {
public static void main(String[] args) {
SpringApplication.run(SpringBoot06DataMybatisApplication.class, args);
}
}
5）配置文件版
mybatis:
#指定全局配置文件的位置
config-location: classpath:mybatis/mybatis-config.xml
# 指定sql映射文件的位置,或者将xml文件与Mapper接口放在同一包下
# mapper-locations: classpath:mybatis/mapper/*.xml 指定sql映射文件的位置
更多使用参照
http://www.mybatis.org/spring-boot-starter/mybatis-spring-boot-autoconfigure/
4. 整合SpringData JPA
JPA:ORM（Object Relational Mapping）；
1）、编写一个实体类（bean）和数据表进行映射，并且配置好映射关系；
//使用JPA注解配置映射关系
@Entity //告诉JPA这是一个实体类（和数据表映射的类）
@Table(name = "tbl_user") //@Table来指定和哪个数据表对应;如果省略默认表名就是user；
public class User {
@Id //这是一个主键
@GeneratedValue(strategy = GenerationType.IDENTITY)//自增主键
private Integer id;
@Column(name = "last_name",length = 50) //这是和数据表对应的一个列
private String lastName;
@Column //省略默认列名就是属性名
private String email;
2）、编写一个Dao接口来操作实体类对应的数据表（Repository）
//继承JpaRepository来完成对数据库的操作
public interface UserRepository extends JpaRepository<User,Integer> {
}
3）、基本的配置JpaProperties
spring:
jpa:
hibernate:
# 更新或者创建数据表结构
ddl-auto: update
# 控制台显示SQL
show-sql: true
