Springboot—数据访问

目录

SQL：

自动配置分析：

  DataSourceAutoConfiguration：数据源的自动配置

JdbcTemplateAutoConfiguration:

Druid数据源：

DruidDataSourceAutoConfigure

然后我们看下关键的DruidStatProperties：

DruidDataSourceAutoConfigure:

 yml全部：

自定义实现监控页与监控功能：

SQL：

   1.首先导入JDBC场景：

 
            org.springframework.boot
            spring-boot-starter-data-jdbc
        

2.然后我们导入驱动（数据库版本尽量与驱动版本保持一致）：

            mysql
            mysql-connector-java
            5.1.49
        

自动配置分析：

  DataSourceAutoConfiguration：数据源的自动配置

@EnableConfigurationProperties({DataSourceProperties.class})
@import({DataSourcePoolmetadataProvidersConfiguration.class, DataSourceInitializationConfiguration.class})
public class DataSourceAutoConfiguration {
    public DataSourceAutoConfiguration() {
    }

  可以发现底层默认配置好的连接池为：HikariDataSource

	@Configuration(proxyBeanMethods = false)
	@Conditional(PooledDataSourceCondition.class)
	@ConditionalOnMissingBean({ DataSource.class, XADataSource.class })
	@import({ DataSourceConfiguration.Hikari.class, DataSourceConfiguration.Tomcat.class,
			DataSourceConfiguration.Dbcp2.class, DataSourceConfiguration.OracleUcp.class,
			DataSourceConfiguration.Generic.class, DataSourceJmxConfiguration.class })
	protected static class PooledDataSourceConfiguration

然后我们看看被数据源自动配置所绑定的DataSourceProperties：

@ConfigurationProperties(
    prefix = "spring.datasource"
)
public class DataSourceProperties implements BeanClassLoaderAware, InitializingBean {
    private ClassLoader classLoader;
    private boolean generateUniqueName = true;
    private String name;
    private Class type;
    private String driverClassName;
    private String url;
    private String username;
    private String password;
    private String jndiName;

所以说我们可以用yml对数据源驱动进行配置（以spring.datasource.xxx进行配置）

spring:
  datasource:
    url: jdbc:mysql://localhost:3306/db_account
    username: root
    password: 123456
    driver-class-name: com.mysql.jdbc.Driver

JdbcTemplateAutoConfiguration:

  JdbcTemplate的自动配置，里面有对数据库的crud；

@Configuration(
    proxyBeanMethods = false
)
@ConditionalOnClass({DataSource.class, JdbcTemplate.class})
@ConditionalOnSingleCandidate(DataSource.class)
@AutoConfigureAfter({DataSourceAutoConfiguration.class})
@EnableConfigurationProperties({JdbcProperties.class})
@import({JdbcTemplateConfiguration.class, NamedParameterJdbcTemplateConfiguration.class})
public class JdbcTemplateAutoConfiguration {
    public JdbcTemplateAutoConfiguration() {
    }
}

JdbcProperties中绑定了jdbc操作（以spring.jdbc.xxx在yml中配置）：

@ConfigurationProperties(
    prefix = "spring.jdbc"
)
public class JdbcProperties {
    private final JdbcProperties.Template template = new JdbcProperties.Template();

    public JdbcProperties() {
    }

扩：

DataSourceTransactionManagerAutoConfiguration： 事务管理器的自动配置

JdbcTemplateAutoConfiguration： JdbcTemplate的自动配置，可以来对数据库进行crud

可以修改这个配置项@ConfigurationProperties(prefix = "spring.jdbc") 来修改JdbcTemplate@Bean@Primary JdbcTemplate；容器中有这个组件

JndiDataSourceAutoConfiguration： jndi的自动配置

XADataSourceAutoConfiguration： 分布式事务相关的

测试：

@Slf4j
@SpringBootTest
class Boot05WebAdminApplicationTests {

    @Autowired
    JdbcTemplate jdbcTemplate;


    @Test
    void contextLoads() {

//        jdbcTemplate.queryForObject("select * from account_tbl")
//        jdbcTemplate.queryForList("select * from account_tbl",)
        Long aLong = jdbcTemplate.queryForObject("select count(*) from account_tbl", Long.class);
        log.info("记录总数：{}",aLong);
    }

}

Druid数据源：

  这里放上druid的文档

https://github.com/alibaba/druid/wiki/%E5%B8%B8%E8%A7%81%E9%97%AE%E9%A2%98English https://github.com/alibaba/druid/wiki/FAQ

  在springboot中，我们不能像之前那样导入bean来配置数据源，或者在web.xml中通过servlet映射来配置功能了；

而是自定义Configuration，注册组件的方式或者通过yaml配置的方式来配置数据源增加配置功能；

DruidDataSourceAutoConfigure

 可以发现它是要在DataSourceAutoConfiguration之前执行的，因为DataSourceAutoConfiguration里面配置了默认数据源，所以要先执行；

@Configuration
@ConditionalOnClass({DruidDataSource.class})
@AutoConfigureBefore({DataSourceAutoConfiguration.class})
@EnableConfigurationProperties({DruidStatProperties.class, DataSourceProperties.class})
@import({DruidSpringAopConfiguration.class, DruidStatViewServletConfiguration.class, DruidWebStatFilterConfiguration.class, DruidFilterConfiguration.class})
public class DruidDataSourceAutoConfigure {
    private static final Logger LOGGER = LoggerFactory.getLogger(DruidDataSourceAutoConfigure.class);

    public DruidDataSourceAutoConfigure() {
    }

    @Bean(
        initMethod = "init"
    )
    @ConditionalOnMissingBean
    public DataSource dataSource() {
        LOGGER.info("Init DruidDataSource");
        return new DruidDataSourceWrapper();
    }
}

然后我们看下关键的DruidStatProperties：

里面能够配置的东西有很多：以spring.datasource.druid为前缀，实现aoppatterns（监控springBean）；还可以开启filters：stat,wall,slf4j等功能（全局性的，不是具体的）

大致有两个功能：1：StatViewServlet:配置监控页功能；2：WebStatFilter:监控web

@ConfigurationProperties("spring.datasource.druid")
public class DruidStatProperties {
    private String[] aopPatterns;
    private DruidStatProperties.StatViewServlet statViewServlet = new DruidStatProperties.StatViewServlet();
    private DruidStatProperties.WebStatFilter webStatFilter = new DruidStatProperties.WebStatFilter();

    public DruidStatProperties() {
    }

    public String[] getAopPatterns() {
        return this.aopPatterns;
    }

    public void setAopPatterns(String[] aopPatterns) {
        this.aopPatterns = aopPatterns;
    }

    public DruidStatProperties.StatViewServlet getStatViewServlet() {
        return this.statViewServlet;
    }

    public void setStatViewServlet(DruidStatProperties.StatViewServlet statViewServlet) {
        this.statViewServlet = statViewServlet;
    }

    public DruidStatProperties.WebStatFilter getWebStatFilter() {
        return this.webStatFilter;
    }

    public void setWebStatFilter(DruidStatProperties.WebStatFilter webStatFilter) {
        this.webStatFilter = webStatFilter;
    }

    public static class WebStatFilter {
        private boolean enabled;
        private String urlPattern;
        private String exclusions;
        private String sessionStatMaxCount;
        private String sessionStatEnable;
        private String principalSessionName;
        private String principalcookieName;
        private String profileEnable;}

 public static class StatViewServlet {
        private boolean enabled;
        private String urlPattern;
        private String allow;
        private String deny;
        private String loginUsername;
        private String loginPassword;
        private String resetEnable;}

 在yml中实现对statviewServlet与webstatFilter的全局配置：

spring:
  datasource:
    url: jdbc:mysql://localhost:3306/db_account
    username: Wuyuhang
    password: 2002514wyh11
    driver-class-name: com.mysql.jdbc.Driver

    druid:
      filters: stat,wall,slf4j #开启监控和防火墙and日志功能
      stat-view-servlet: admin
        login-password: 123456
        reset-enable: false
#监控web应用
      web-stat-filter:
        enabled: true
        url-pattern: 
    @Bean
    public ServletRegistrationBean statViewServlet(){
//        statViewServlet就是监控视图响应
        StatViewServlet statViewServlet = new StatViewServlet();
        ServletRegistrationBean registrationBean = new ServletRegistrationBean<>(statViewServlet, "/druid
    @Bean
    public FilterRegistrationBean webStatFilter(){
        WebStatFilter webStatFilter = new WebStatFilter();

        FilterRegistrationBean filterRegistrationBean = new FilterRegistrationBean<>(webStatFilter);
        filterRegistrationBean.setUrlPatterns(Arrays.asList("/*"));
        filterRegistrationBean.addInitParameter("exclusions","*.js,*.gif,*.jpg,*.png,*.css,*.ico,/druid/*");

        return filterRegistrationBean;
    }