前言

Druid是阿里巴巴开源的数据库连接池，号称是Java语言中最好的数据库连接池，能够提供强大的监控和扩展功能。GitHub地址：https://github.com/alibaba/druid。

1、pom.xml文件

添加jpa、mysql和druid依赖。

    <properties>
        <java.version>1.8</java.version>
        <druid.version>1.1.16</druid.version>
    </properties>

    <dependencies>
        <!--jpa-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <scope>runtime</scope>
            <optional>true</optional>
        </dependency>
        <!--mysql-->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <!--druid-->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid</artifactId>
            <version>${druid.version}</version>
        </dependency>
    </dependencies>

2、配置文件

server:
  port: 8080
spring:
  datasource:
    url: jdbc:mysql://localhost:3306/test?serverTimezone=GMT
    username: root
    password: 123456
    driver-class-name: com.mysql.jdbc.Driver
    type: com.alibaba.druid.pool.DruidDataSource
    # 初始化大小，最小，最大
    initialSize: 5
    minIdle: 5
    maxActive: 20
    # 配置获取连接等待超时的时间
    maxWait: 60000
    # 配置间隔多久才进行一次检测，检测需要关闭的空闲连接，单位是毫秒
    timeBetweenEvictionRunsMillis: 60000
    # 配置一个连接在池中最小生存的时间，单位是毫秒
    minEvictableIdleTimeMillis: 300000
    # Oracle请使用select 1 from dual
    validationQuery: select 'x'
    testWhileIdle: true
    testOnBorrow: true
    testOnReturn: false
    # 打开PSCache，并且指定每个连接上PSCache的大小
    poolPreparedStatements: true
    # 配置监控统计拦截的filters，去掉后监控界面sql无法统计，'wall'用于防火墙
    filters: stat,wall,slf4j
    maxPoolPreparedStatementPerConnectionSize: 20
    # 合并多个DruidDataSource的监控数据
    useGlobalDataSourceStat: true
    # 通过connectProperties属性来打开mergeSql功能；慢SQL记录
    connectionProperties: druid.stat.mergeSql=true;druid.stat.slowSqlMillis=500
  jpa:
    #配置 DBMS 类型
    database: MYSQL
    show-sql: true
    properties:
      hibernate:
        hbm2ddl:
          auto: update
        dialect: org.hibernate.dialect.MySQL5InnoDBDialect

3、Druid配置类

@Configuration
public class DruidConfig {

    private Logger logger = LoggerFactory.getLogger(this.getClass());

    @Value("${spring.datasource.url}")
    private String dbUrl;

    @Value("${spring.datasource.username}")
    private String username;

    @Value("${spring.datasource.password}")
    private String password;

    @Value("${spring.datasource.driver-class-name}")
    private String driverClassName;

    @Value("${spring.datasource.initialSize}")
    private int initialSize;

    @Value("${spring.datasource.minIdle}")
    private int minIdle;

    @Value("${spring.datasource.maxActive}")
    private int maxActive;

    @Value("${spring.datasource.maxWait}")
    private int maxWait;

    @Value("${spring.datasource.timeBetweenEvictionRunsMillis}")
    private int timeBetweenEvictionRunsMillis;

    @Value("${spring.datasource.minEvictableIdleTimeMillis}")
    private int minEvictableIdleTimeMillis;

    @Value("${spring.datasource.validationQuery}")
    private String validationQuery;

    @Value("${spring.datasource.testWhileIdle}")
    private boolean testWhileIdle;

    @Value("${spring.datasource.testOnBorrow}")
    private boolean testOnBorrow;

    @Value("${spring.datasource.testOnReturn}")
    private boolean testOnReturn;

    @Value("${spring.datasource.poolPreparedStatements}")
    private boolean poolPreparedStatements;

    @Value("${spring.datasource.maxPoolPreparedStatementPerConnectionSize}")
    private int maxPoolPreparedStatementPerConnectionSize;

    @Value("${spring.datasource.filters}")
    private String filters;

    @Value("{spring.datasource.connectionProperties}")
    private String connectionProperties;

    @Bean
    @Primary  //主数据源
    public DataSource dataSource() {
        DruidDataSource datasource = new DruidDataSource();
        logger.info("----------- druid datasource ----------");

        datasource.setUrl(this.dbUrl);
        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) {
            logger.error("druid configuration Exception", e);
        }
        datasource.setConnectionProperties(connectionProperties);

        return datasource;
    }

    /**
     * 自定义的Servlet注册
     *
     * @return
     */
    @Bean
    public ServletRegistrationBean statViewServlet() {
        // 创建servlet注册实体
        ServletRegistrationBean servletRegistrationBean = new ServletRegistrationBean(new StatViewServlet());
        //druid监控统计路径
        servletRegistrationBean.addUrlMappings("/druid/*");
        // 设置ip白名单(没有配置或者为空，则允许所有访问)
        servletRegistrationBean.addInitParameter("allow", "");
        // 设置ip黑名单,如果allow与deny共同存在时,deny优先于allow
        servletRegistrationBean.addInitParameter("deny", "");
        // 设置控制台管理用户
        servletRegistrationBean.addInitParameter("loginUsername", "admin");
        servletRegistrationBean.addInitParameter("loginPassword", "admin");
        // 是否可以重置数据
        servletRegistrationBean.addInitParameter("resetEnable", "false");
        return servletRegistrationBean;
    }

    /**
     * 自定义的Filter注册
     * @return
     */
    @Bean
    public FilterRegistrationBean statFilter() {
        // 创建过滤器
        FilterRegistrationBean filterRegistrationBean = new FilterRegistrationBean(new WebStatFilter());
//        filterRegistrationBean.setName("druidWebStatFilter");
        // 设置过滤器过滤路径
        filterRegistrationBean.addUrlPatterns("/*");
        // 忽略过滤的形式
        filterRegistrationBean.addInitParameter("exclusions", "*.js,*.gif,*.jpg,*.bmp,*.png,*.css,*.ico,/druid/*");
        return filterRegistrationBean;
    }
}

4、实体类

@Entity
@Table(name = "city")
public class City {

    @Id
    @GeneratedValue(generator = "system-uuid")
    @GenericGenerator(name = "system-uuid", strategy = "uuid")
    private String cityId;
    private String cityName;
    private String cityIntroduce;

    public City(String cityId, String cityName, String cityIntroduce) {
        this.cityId = cityId;
        this.cityName = cityName;
        this.cityIntroduce = cityIntroduce;
    }

    public City(String cityName, String cityIntroduce) {
        this.cityName = cityName;
        this.cityIntroduce = cityIntroduce;
    }

    public City() {
    }

    public String getCityId() {
        return cityId;
    }

    public void setCityId(String cityId) {
        this.cityId = cityId;
    }

    public String getCityName() {
        return cityName;
    }

    public void setCityName(String cityName) {
        this.cityName = cityName;
    }

    public String getCityIntroduce() {
        return cityIntroduce;
    }

    public void setCityIntroduce(String cityIntroduce) {
        this.cityIntroduce = cityIntroduce;
    }
}

5、Repository类

public interface CityRepository extends JpaRepository<City, String> {

    void deleteByCityId(String id);

    City findByCityId(String id);
}

6、controller类

@RestController
public class CityController {

    @Autowired
    private CityRepository cityRepository;


    //http://localhost:8080/saveCity?cityName=北京&cityIntroduce=中国首都
    @GetMapping(value = "saveCity")
    public String saveCity(String cityName, String cityIntroduce) {
        City city = new City(cityName, cityIntroduce);
        cityRepository.save(city);
        return "success";
    }

    //http://localhost:8080/deleteCity?cityId=2
    @GetMapping(value = "deleteCity")
    @Transactional
    public String deleteCity(String cityId) {
        cityRepository.deleteByCityId(cityId);
        return "success";
    }

    //http://localhost:8080/updateCity?cityId=3&cityName=郑州&cityIntroduce=河南省省会
    @GetMapping(value = "updateCity")
    public String updateCity(String cityId, String cityName, String cityIntroduce) {
        City city = new City(cityId, cityName, cityIntroduce);
        cityRepository.save(city);
        return "success";
    }

    //http://localhost:8080/getCityById?cityId=3
    @GetMapping(value = "getCityById")
    public City getCityById(String cityId) {
        City city = cityRepository.findByCityId(cityId);
        return city;
    }
}

7、启动项目

• 访问http://localhost:8080/druid/login.html
  
  image.png

• 登录

  
  
  image.png