SpringBoot接入Druid

╰半夏微凉° 2022-02-05 01:39 233阅读 0赞

# 1. Druid简介 #

java程序很大一部分要操作数据库，为了提高性能操作数据库的时候，有不得不使用数据库连接池。数据库连接池有很多选择，c3p、dhcp、proxool等，druid作为一名后起之秀，凭借其出色的性能，也逐渐印入了大家的眼帘。接下来本教程就说一下druid的简单使用。

GitHub：`https://github.com/alibaba/druid`

# 2.引入依赖 #

<dependency>
        <groupId>com.alibaba</groupId>
        <artifactId>druid</artifactId>
        <version>1.1.12</version>
    </dependency>

# 3. 添加配置文件 #

在application.yml中添加配置属性如下：

spring:
      datasource:
        driver-class-name: com.mysql.jdbc.Driver
        url: jdbc:mysql://127.0.0.1:3306/blog?characterEncoding=utf-8&allowMultiQueries=true
        username: root
        password: root
    
        type: com.alibaba.druid.pool.DruidDataSource
        initialSize: 10
        minIdle: 5
        maxActive: 20
        maxWait: 60000
        timeBetweenEvictionRunsMillis: 60000
        minEvictableIdleTimeMillis: 300000
        validationQuery: SELECT 1 FROM DUAL
        testWhileIdle: true
        testOnBorrow: true
        testOnReturn: false
        poolPreparedStatements: true
        filters: stat
        maxPoolPreparedStatementPerConnectionSize: 20
        useGlobalDataSourceStat: true
        connectionProperties: druid.stat.mergeSql=true;druid.stat.slowSqlMillis=500
      druid:
        loginUsername: admin
        loginPassword: admin

其中的`spring.druid.loginUsernama`和`spring.druid.loginPassword`是自定义属性，用于登录Druid控制台的用户名和密码

# 4. 读取配置属性 #

新建文件`DruidProperties.java`，使用`@ConfigurationProperties`读取`application.yml`中的属性，封装后供其他地方使用，如下：

@ConfigurationProperties(prefix = "spring.druid")
    @NoArgsConstructor
    @Data
    public class DruidProperties {
        private String loginUsername;
        private String loginPassword;
    }

注：*该类必须有`Getter()`和`Setter()`方法，此处用Lombok中的`@Data`代替*

# 5. 编写Druid配置文件 #

新建文件`DruidConfig.java`，如下：

@Configuration
    @EnableConfigurationProperties(DruidProperties.class)      
    public class DruidConfig {
    
        @Bean
        @ConfigurationProperties(prefix = "spring.datasource")
        public DataSource initDruidDataSource() {
            DruidDataSource druidDataSource = new DruidDataSource();
            WallConfig wallConfig = new WallConfig();
            wallConfig.setMultiStatementAllow(true);
            WallFilter wallFilter = new WallFilter();
            wallFilter.setConfig(wallConfig);
            List<Filter> filters = new ArrayList<>();
            filters.add(wallFilter);
            druidDataSource.setProxyFilters(filters);
            return druidDataSource;
        }
    
        /**
         * Druid监控功能页面
         * @param prop
         * @return
         */
        @Bean
        public ServletRegistrationBean statViewServlet(DruidProperties prop) {
            ServletRegistrationBean registrationBean = new ServletRegistrationBean();
            registrationBean.setServlet(new StatViewServlet());
            registrationBean.setUrlMappings(Collections.singletonList("/druid/*"));
            //设置初始化参数
            Map<String,String> initMap = new HashMap<>();
            initMap.put("loginUsername", prop.getLoginUsername());
            initMap.put("loginPassword", prop.getLoginPassword());
            initMap.put("allow","");
            initMap.put("deny","");
            registrationBean.setInitParameters(initMap);
            return registrationBean;
        }
    
        /**
         * Druid监控功能的过滤器设置
         * @return
         */
        @Bean
        public FilterRegistrationBean webStatFilter() {
            FilterRegistrationBean registrationBean = new FilterRegistrationBean();
            registrationBean.setFilter(new WebStatFilter());
            registrationBean.setUrlPatterns(Collections.singletonList("/*"));
            // 设置初始化参数
            Map<String, String> initMap = new HashMap<>();
            initMap.put("exclusions","*.js,*.gif,*.jpg,*.png,*.css,*.ico");
            registrationBean.setInitParameters(initMap);
            return registrationBean;
        }
    }

# 6. 访问Druid监控页面 #

启动项目，访问路径为`项目路径/druid`，如`localhost:8080/druid`，输入配置的用户名和密码，进入主页面  
![Druid页面][Druid]  
至此，Druid接入并配置成功！

[Druid]: /images/20220205/12a1bc2d6b0d45d6ba2494598cb31d98.png