導讀

最近一段時間比較忙，以至於很久沒有更新Spring Boot系列文章，恰好最近用到Druid， 就將Spring Boot 使用 Druid作為資料來源做一個簡單的介紹。

Druid介紹：

Druid是阿里巴巴開源的資料庫連線池，Druid號稱是Java語言中最好的資料庫連線池，並且能夠提供強大的監控和擴充套件功能，Druid的官方地址

瞭解更多：

快速上手：

下面來說明如何在 spring Boot 中配置使用Druid ，本例使用的持久層框為Spring Boot JPA。

第一步：新增pom依賴:

<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檔案 資料來源相關資訊

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
 

      # 下面為連線池的補充設定，應用到上面所有資料來源中
      # 初始化大小，最小，最大
      initialSize: 1
      minIdle: 3
      maxActive: 20
      # 配置獲取連線等待超時的時間
      maxWait: 60000
      # 配置間隔多久才進行一次檢測，檢測需要關閉的空閒連線，單位是毫秒
      timeBetweenEvictionRunsMillis: 60000
      # 配置一個連線在池中最小生存的時間，單位是毫秒
      minEvictableIdleTimeMillis: 30000
      validationQuery: select 'x'
      testWhileIdle: true
      testOnBorrow: false
      testOnReturn: false
      # 開啟PSCache，並且指定每個連線上PSCache的大小
      poolPreparedStatements: true
      maxPoolPreparedStatementPerConnectionSize: 20
      # 配置監控統計攔截的filters，去掉後監控介面sql無法統計，'wall'用於防火牆
      filters: stat,wall,slf4j
      # 通過connectProperties屬性來開啟mergeSql功能；慢SQL記錄
      connectionProperties: druid.stat.mergeSql=true;druid.stat.slowSqlMillis=5000
      # 合併多個DruidDataSource的監控資料
      #useGlobalDataSourceStat: true

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

第三步：配置Druid的監控統計功能

這裡有兩種方式 ：
第一種方式@Confing註解 配置類:

@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白名單
        servletRegistrationBean.addInitParameter("allow", "192.168.2.25,127.0.0.1");
        // IP黑名單(共同存在時，deny優先於allow)
        servletRegistrationBean.addInitParameter("deny", "192.168.1.100");
        //控制檯管理使用者
        servletRegistrationBean.addInitParameter("loginUsername", "admin");
        servletRegistrationBean.addInitParameter("loginPassword", "admin");
        //是否能夠重置資料 禁用HTML頁面上的“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;
    }

    //解決 spring.datasource.filters=stat,wall,log4j 無法正常註冊進去
    @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     //宣告其為Bean例項
        @Primary  //在同樣的DataSource中，首先使用被標註的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;
        }
    }

}

第二種方式基於註解的配置:

首先在啟動類上加上註解：@ServletComponentScan使Spring能夠掃描到我們自己編寫的servlet和filter。

//druid資料來源狀態監控.
@WebServlet(urlPatterns = "/druid/*",
    initParams = {
        // IP白名單 (沒有配置或者為空，則允許所有訪問)
        @WebInitParam(name = "allow", value = "192.168.1.72,127.0.0.1"),
        // IP黑名單 (存在共同時，deny優先於allow)
        @WebInitParam(name = "deny", value = "192.168.1.73"),
        // 使用者名稱
        @WebInitParam(name = "loginUsername", value = "admin"),
        // 密碼
        @WebInitParam(name = "loginPassword", value = "admin"),
        // 禁用HTML頁面上的“Reset All”功能
        @WebInitParam(name = "resetEnable", value = "false")
    }
)
public class DruidStatViewServlet extends StatViewServlet {

}

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

參考資料：