Spring Boot [使用 Druid 数据库链接池]

导读

最近一段时间比较忙，以致于好久没有更新Spring Boot系列文章，刚好最近用到Druid， 就将Spring Boot 使用 Druid做为数据源作一个简单的介绍。

Druid介绍：

Druid是阿里巴巴开源的数据库链接池，Druid号称是Java语言中最好的数据库链接池，而且可以提供强大的监控和扩展功能，Druid的官方地址

了解更多：

JDBC链接池、监控组件 Druid （oschina）

快速上手：

下面来讲明如何在 spring Boot 中配置使用Druid ，本例使用的持久层框为Spring Boot JPA。

第一步：添加pom依赖:

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-data-jpa</artifactId>
</dependency>
<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>druid</artifactId>
    <version>1.0.20</version>
</dependency>

第二步：配置yml文件 数据源相关信息

spring:
  datasource:
      url: jdbc:mysql://localhost:3306/sanji-boot?useUnicode=true&characterEncoding=utf-8&useSSL=false
      username: root
      password: 123456
      driver-class-name: com.mysql.jdbc.Driver
      platform: mysql
      type: com.alibaba.druid.pool.DruidDataSource
      # 下面为链接池的补充设置，应用到上面全部数据源中
      # 初始化大小，最小，最大
      initialSize: 1
      minIdle: 3
      maxActive: 20
      # 配置获取链接等待超时的时间
      maxWait: 60000
      # 配置间隔多久才进行一次检测，检测须要关闭的空闲链接，单位是毫秒
      timeBetweenEvictionRunsMillis: 60000
      # 配置一个链接在池中最小生存的时间，单位是毫秒
      minEvictableIdleTimeMillis: 30000
      validationQuery: select 'x'
      testWhileIdle: true
      testOnBorrow: false
      testOnReturn: false
      # 打开PSCache，而且指定每一个链接上PSCache的大小
      poolPreparedStatements: true
      maxPoolPreparedStatementPerConnectionSize: 20
      # 配置监控统计拦截的filters，去掉后监控界面sql没法统计，'wall'用于防火墙
      filters: stat,wall,slf4j
      # 经过connectProperties属性来打开mergeSql功能；慢SQL记录
      connectionProperties: druid.stat.mergeSql=true;druid.stat.slowSqlMillis=5000
      # 合并多个DruidDataSource的监控数据
      #useGlobalDataSourceStat: true

  jpa:
    show-sql: true
    properties:
      hibernate:
        hbm2ddl:
          auto: create

第三步：配置Druid的监控统计功能

这里有两种方式 ：
第一种方式@Confing注解 配置类:

@Configuration
public class DruidConfiguration {

    private static final Logger logger = LoggerFactory.getLogger(DruidConfiguration.class);

    private static final String DB_PREFIX = "spring.datasource";

    @Bean
    public ServletRegistrationBean druidServlet() {
        logger.info("init Druid Servlet Configuration ");
        ServletRegistrationBean servletRegistrationBean = new ServletRegistrationBean(new StatViewServlet(), "/druid/*");
        // IP白名单
        servletRegistrationBean.addInitParameter("allow", "192.168.2.25,127.0.0.1");
        // IP黑名单(共同存在时，deny优先于allow)
        servletRegistrationBean.addInitParameter("deny", "192.168.1.100");
        //控制台管理用户
        servletRegistrationBean.addInitParameter("loginUsername", "admin");
        servletRegistrationBean.addInitParameter("loginPassword", "admin");
        //是否可以重置数据 禁用HTML页面上的“Reset All”功能
        servletRegistrationBean.addInitParameter("resetEnable", "false");
        return servletRegistrationBean;
    }

    @Bean
    public FilterRegistrationBean filterRegistrationBean() {
        FilterRegistrationBean filterRegistrationBean = new FilterRegistrationBean(new WebStatFilter());
        filterRegistrationBean.addUrlPatterns("/*");
        filterRegistrationBean.addInitParameter("exclusions", "*.js,*.gif,*.jpg,*.png,*.css,*.ico,/druid/*");
        return filterRegistrationBean;
    }

    //解决 spring.datasource.filters=stat,wall,log4j 没法正常注册进去
    @ConfigurationProperties(prefix = DB_PREFIX)
    class IDataSourceProperties {
        private String url;
        private String username;
        private String password;
        private String driverClassName;
        private int initialSize;
        private int minIdle;
        private int maxActive;
        private int maxWait;
        private int timeBetweenEvictionRunsMillis;
        private int minEvictableIdleTimeMillis;
        private String validationQuery;
        private boolean testWhileIdle;
        private boolean testOnBorrow;
        private boolean testOnReturn;
        private boolean poolPreparedStatements;
        private int maxPoolPreparedStatementPerConnectionSize;
        private String filters;
        private String connectionProperties;

        @Bean     //声明其为Bean实例
        @Primary  //在一样的DataSource中，首先使用被标注的DataSource
        public DataSource dataSource() {
            DruidDataSource datasource = new DruidDataSource();
            datasource.setUrl(url);
            datasource.setUsername(username);
            datasource.setPassword(password);
            datasource.setDriverClassName(driverClassName);

            //configuration
            datasource.setInitialSize(initialSize);
            datasource.setMinIdle(minIdle);
            datasource.setMaxActive(maxActive);
            datasource.setMaxWait(maxWait);
            datasource.setTimeBetweenEvictionRunsMillis(timeBetweenEvictionRunsMillis);
            datasource.setMinEvictableIdleTimeMillis(minEvictableIdleTimeMillis);
            datasource.setValidationQuery(validationQuery);
            datasource.setTestWhileIdle(testWhileIdle);
            datasource.setTestOnBorrow(testOnBorrow);
            datasource.setTestOnReturn(testOnReturn);
            datasource.setPoolPreparedStatements(poolPreparedStatements);
            datasource.setMaxPoolPreparedStatementPerConnectionSize(maxPoolPreparedStatementPerConnectionSize);
            try {
                datasource.setFilters(filters);
            } catch (SQLException e) {
                System.err.println("druid configuration initialization filter: " + e);
            }
            datasource.setConnectionProperties(connectionProperties);
            return datasource;
        }

        public String getUrl() {
            return url;
        }

        public void setUrl(String url) {
            this.url = url;
        }

        public String getUsername() {
            return username;
        }

        public void setUsername(String username) {
            this.username = username;
        }

        public String getPassword() {
            return password;
        }

        public void setPassword(String password) {
            this.password = password;
        }

        public String getDriverClassName() {
            return driverClassName;
        }

        public void setDriverClassName(String driverClassName) {
            this.driverClassName = driverClassName;
        }

        public int getInitialSize() {
            return initialSize;
        }

        public void setInitialSize(int initialSize) {
            this.initialSize = initialSize;
        }

        public int getMinIdle() {
            return minIdle;
        }

        public void setMinIdle(int minIdle) {
            this.minIdle = minIdle;
        }

        public int getMaxActive() {
            return maxActive;
        }

        public void setMaxActive(int maxActive) {
            this.maxActive = maxActive;
        }

        public int getMaxWait() {
            return maxWait;
        }

        public void setMaxWait(int maxWait) {
            this.maxWait = maxWait;
        }

        public int getTimeBetweenEvictionRunsMillis() {
            return timeBetweenEvictionRunsMillis;
        }

        public void setTimeBetweenEvictionRunsMillis(int timeBetweenEvictionRunsMillis) {
            this.timeBetweenEvictionRunsMillis = timeBetweenEvictionRunsMillis;
        }

        public int getMinEvictableIdleTimeMillis() {
            return minEvictableIdleTimeMillis;
        }

        public void setMinEvictableIdleTimeMillis(int minEvictableIdleTimeMillis) {
            this.minEvictableIdleTimeMillis = minEvictableIdleTimeMillis;
        }

        public String getValidationQuery() {
            return validationQuery;
        }

        public void setValidationQuery(String validationQuery) {
            this.validationQuery = validationQuery;
        }

        public boolean isTestWhileIdle() {
            return testWhileIdle;
        }

        public void setTestWhileIdle(boolean testWhileIdle) {
            this.testWhileIdle = testWhileIdle;
        }

        public boolean isTestOnBorrow() {
            return testOnBorrow;
        }

        public void setTestOnBorrow(boolean testOnBorrow) {
            this.testOnBorrow = testOnBorrow;
        }

        public boolean isTestOnReturn() {
            return testOnReturn;
        }

        public void setTestOnReturn(boolean testOnReturn) {
            this.testOnReturn = testOnReturn;
        }

        public boolean isPoolPreparedStatements() {
            return poolPreparedStatements;
        }

        public void setPoolPreparedStatements(boolean poolPreparedStatements) {
            this.poolPreparedStatements = poolPreparedStatements;
        }

        public int getMaxPoolPreparedStatementPerConnectionSize() {
            return maxPoolPreparedStatementPerConnectionSize;
        }

        public void setMaxPoolPreparedStatementPerConnectionSize(int maxPoolPreparedStatementPerConnectionSize) {
            this.maxPoolPreparedStatementPerConnectionSize = maxPoolPreparedStatementPerConnectionSize;
        }

        public String getFilters() {
            return filters;
        }

        public void setFilters(String filters) {
            this.filters = filters;
        }

        public String getConnectionProperties() {
            return connectionProperties;
        }

        public void setConnectionProperties(String connectionProperties) {
            this.connectionProperties = connectionProperties;
        }
    }

}

第二种方式基于注解的配置:

首先在启动类上加上注解：@ServletComponentScan使Spring可以扫描到咱们本身编写的servlet和filter。

//druid数据源状态监控.
@WebServlet(urlPatterns = "/druid/*",
    initParams = {
        // IP白名单 (没有配置或者为空，则容许全部访问)
        @WebInitParam(name = "allow", value = "192.168.1.72,127.0.0.1"),
        // IP黑名单 (存在共同时，deny优先于allow)
        @WebInitParam(name = "deny", value = "192.168.1.73"),
        // 用户名
        @WebInitParam(name = "loginUsername", value = "admin"),
        // 密码
        @WebInitParam(name = "loginPassword", value = "admin"),
        // 禁用HTML页面上的“Reset All”功能
        @WebInitParam(name = "resetEnable", value = "false")
    }
)
public class DruidStatViewServlet extends StatViewServlet {

}

// druid过滤器. 
@WebFilter(filterName = "druidWebStatFilter", urlPatterns = "/*",
    initParams = {
        // 忽略资源
        @WebInitParam(name = "exclusions", value = "*.js,*.gif,*.jpg,*.bmp,*.png,*.css,*.ico,/druid/*")
    }
)
public class DruidStatFilter extends WebStatFilter {
}

等应用启动后，能够访问地址：http://localhost:8080/druid/，登陆以后，便可查看数据源及SQL统计等。
效果图以下：

参考资料：

官方地址
Spring Boot 使用 Druid
Spring Boot集成Druid数据库链接池
SPRING BOOT使用DRUID和监控配置方法