增加druid监控的配置

1、POM.xml增加引入：

<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>druid-spring-boot-starter</artifactId>
    <version>1.1.10</version>
</dependency>

2、Application.properties增加配置：

spring.datasource.filters: stat

3、添加配置类DruidConfig：

@Configuration
public class DruidConfig {

    //将所有前缀为spring.datasource下的配置项都加载到DataSource中
    @ConfigurationProperties(prefix = "spring.datasource")
    @Bean
    public DataSource dataSource() {
        return new DruidDataSource();
    }
    @Bean
    public static PropertySourcesPlaceholderConfigurer propertyConfigure(){
        return new PropertySourcesPlaceholderConfigurer();
    }
    @Bean
    public PlatformTransactionManager transactionManager() throws Exception {
        DataSourceTransactionManager txManager = new DataSourceTransactionManager();
        txManager.setDataSource(dataSource());
        return txManager;
    }
    @Bean
    public ServletRegistrationBean druidStatViewServlet() {
        ServletRegistrationBean servletRegistrationBean = new ServletRegistrationBean(new StatViewServlet(),"/druid/*");
        Map<String, String> initParams = new HashMap<>();
        //　可配的属性都在 StatViewServlet 和其父类下
        initParams.put("loginUsername", "admin-druid");
        initParams.put("loginPassword", "111111");
        servletRegistrationBean.setInitParameters(initParams);
        return servletRegistrationBean;
    }
    @Bean
    public FilterRegistrationBean druidWebStatFilter() {
        FilterRegistrationBean filterRegistrationBean = new FilterRegistrationBean(new WebStatFilter());
        Map<String, String> initParams = new HashMap<>();
        initParams.put("exclusions", "*.js,*.css,/druid/*");
        filterRegistrationBean.setInitParameters(initParams);
        filterRegistrationBean.setUrlPatterns(Arrays.asList("/*"));
        return filterRegistrationBean;
    }
}

4、在浏览器中访问：http://localhost:8080/druid/login.html，即可打开下面的页面，登录账号：admin-druid：111111（这个账号密码是可以在DruidConfig.druidStatViewServlet方法中修改的）即可打开监控页面；