Spring Boot集成Druid数据库连接池

1. 前言

Druid数据库连接池由阿里巴巴开源,号称是java语言中最好的数据库连接池,是为监控而生的。Druid的官方地址是:https://github.com/alibaba/druid

通过本文,我们可以看到

  • Spring Boot 如何配置数据源
  • Spring Boot 如何集成Druid数据库连接池
  • 如何打开并访问Druid数据库连接池的监控功能
  • Spring Boot 使用JdbcTemplate操作数据库

2. 配置pom.xml

<parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>1.3.5.RELEASE</version>
</parent>

<properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
    <java.version>1.8</java.version>
</properties>

<dependencies>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-jdbc</artifactId>
    </dependency>
    <dependency>
        <groupId>com.alibaba</groupId>
        <artifactId>druid</artifactId>
        <version>1.0.20</version>
    </dependency>
    <dependency>
        <groupId>org.postgresql</groupId>
        <artifactId>postgresql</artifactId>
        <scope>runtime</scope>
    </dependency>
</dependencies>

3. 在application.properties中配置数据源

# 数据库访问配置,此处使用postgres为例。
# 主数据源,默认的
spring.datasource.type=com.alibaba.druid.pool.DruidDataSource
spring.datasource.driver-class-name=org.postgresql.Driver
spring.datasource.url=jdbc:postgresql://192.168.1.9/jianshudb
spring.datasource.username=postgres
spring.datasource.password=yourpassword

# 下面为连接池的补充设置,应用到上面所有数据源中
# 初始化大小,最小,最大
spring.datasource.initialSize=5
spring.datasource.minIdle=5
spring.datasource.maxActive=20
# 配置获取连接等待超时的时间
spring.datasource.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 
spring.datasource.timeBetweenEvictionRunsMillis=60000
# 配置一个连接在池中最小生存的时间,单位是毫秒 
spring.datasource.minEvictableIdleTimeMillis=300000
# Oracle请使用select 1 from dual
spring.datasource.validationQuery=SELECT 'x'
spring.datasource.testWhileIdle=true
spring.datasource.testOnBorrow=false
spring.datasource.testOnReturn=false
# 打开PSCache,并且指定每个连接上PSCache的大小 
spring.datasource.poolPreparedStatements=true
spring.datasource.maxPoolPreparedStatementPerConnectionSize=20
# 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 
spring.datasource.filters=stat,wall,slf4j
# 通过connectProperties属性来打开mergeSql功能;慢SQL记录
#spring.datasource.connectionProperties=druid.stat.mergeSql=true;druid.stat.slowSqlMillis=5000
# 合并多个DruidDataSource的监控数据
#spring.datasource.useGlobalDataSourceStat=true

DruidDataSource参考配置:
https://github.com/alibaba/druid/wiki/%E9%85%8D%E7%BD%AE_DruidDataSource%E5%8F%82%E8%80%83%E9%85%8D%E7%BD%AE

4. 打开Druid的监控统计功能

Druid的监控统计功能是通过filter-chain扩展实现,如果你要打开监控统计功能,需要配置StatFilter,相关代码如下。

@Configuration
public class DruidConfiguration {

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

  @Bean
  public ServletRegistrationBean druidServlet() {
    log.info("init Druid Servlet Configuration ");
    ServletRegistrationBean servletRegistrationBean = new ServletRegistrationBean();
    servletRegistrationBean.setServlet(new StatViewServlet());
    servletRegistrationBean.addUrlMappings("/druid/*");
    Map<String, String> initParameters = new HashMap<String, String>();
    initParameters.put("loginUsername", "admin");// 用户名
    initParameters.put("loginPassword", "admin");// 密码
    initParameters.put("resetEnable", "false");// 禁用HTML页面上的“Reset All”功能
    initParameters.put("allow", ""); // IP白名单 (没有配置或者为空,则允许所有访问)
    //initParameters.put("deny", "192.168.20.38");// IP黑名单 (存在共同时,deny优先于allow)
    servletRegistrationBean.setInitParameters(initParameters);
    return servletRegistrationBean;
  }

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

}

等应用启动后,可以访问地址:http://localhost:8080/druid/,用户名和密码见上述代码中的设置,即admin/admin。

5. 使用JdbcTemplate操作数据库

假设数据库中有表t_user,其中id=1的user的username为ZhangSan。下面的例子演示了通过id查找username的情况。

@RestController
public class DemoController {

    @Autowired
    JdbcTemplate jdbcTemplate;

    @RequestMapping(value = "/hello.do", method = RequestMethod.GET)
    public String hello(@RequestParam(value = "id", required = true) Integer id) {
        String name = getNameById(id);
        return (name == null) ? "Hello World" : ("Hello " + name);
    }

    public String getNameById(Integer id) {
        String sql = "select username from t_user where id = ? ";
        List<String> list = jdbcTemplate.queryForList(sql, new Object[] {id}, String.class);
        return list.isEmpty() ? null : list.get(0);
    }

}

访问地址:http://localhost:8080/hello.do?id=1
结果输出:Hello, ZhangSan

    原文作者:郭寻抚
    原文地址: https://www.jianshu.com/p/c8a01ae9f779
    本文转自网络文章,转载此文章仅为分享知识,如有侵权,请联系博主进行删除。
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