在SpringBoot中利用nacos对数据源进行动态刷新

这里为什么要重写这个类：因为DruidDataSource数据源在初始化后，就不允许再重新设置数据库的url和userName

注意：类所在的包名必须为 com.alibaba.druid.pool

public void setUrl(String jdbcUrl) {
if (StringUtils.equals(this.jdbcUrl, jdbcUrl)) {
return;

}

// 重写的时候，需要将这个判断注释掉，否则会报错

// if (inited) {
// throw new UnsupportedOperationException();

// }

if (jdbcUrl != null) {
jdbcUrl = jdbcUrl.trim();

}

this.jdbcUrl = jdbcUrl;

// if (jdbcUrl.startsWith(ConfigFilter.URL_PREFIX)) {
// this.filters.add(new ConfigFilter());

// }

}

public void setUsername(String username) {
if (StringUtils.equals(this.username, username)) {
return;

}

// 重写的时候，需要将这个判断注释掉，否则会报错

// if (inited) {
// throw new UnsupportedOperationException();

// }

this.username = username;

}

注意: 重写后包路径不能变, 这样就能优先加载自己重写的类

package com.mp.demo.config;

import com.alibaba.druid.pool.DruidDataSource;
import lombok.Data;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.cloud.context.config.annotation.RefreshScope;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

@Slf4j
@Configuration
@RefreshScope //必须要加这个注解,该注解的作用是nacos配置更新后,能马上获取最新的值
@Data
public class DruidConfiguration
{
  @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;

  @Bean
  @RefreshScope
  public DruidDataSource dataSource()
  {
    DruidDataSource datasource = new DruidDataSource();
    datasource.setUrl(this.dbUrl);
    datasource.setUsername(username);
    datasource.setPassword(password);
    datasource.setDriverClassName(driverClassName);
    return datasource;
  }
}

在controller层写一个接口, 每次nacos中更改配置后,手动请求一下该接口,就能切换数据源

 @GetMapping("/refresh")
  public String refresh() throws SQLException
  {
    DruidDataSource master = SpringUtils.getBean("dataSource");
    master.setUrl(druidConfiguration.getDbUrl());
    master.setUsername(druidConfiguration.getUsername());
    master.setPassword(druidConfiguration.getPassword());
    master.setDriverClassName(druidConfiguration.getDriverClassName());
    master.restart();
    return "mysql: " + jdbcUrl+"----------"+druidConfiguration.getDbUrl();
  }