项目中有一个需求,spring boot项目连接postgres数据库的地址,是存储在etcd当中的,在程序启动后,当etcd中的地址变化时,需要程序去连接新的postgres地址。
- 修改Datasource定义,改为使用DynamicPGDataSource,它是一个自定义类,集成了
AbstractRoutingDataSource
@Primary
@Bean
public DataSource druidDataSource() {
DruidDataSource druidDataSource = DruidDataSourceBuilder.create().build();
druidDataSource.setUrl(url);
druidDataSource.setUsername(username);
druidDataSource.setPassword(password);
druidDataSource.setDriverClassName(driverClassName);
druidDataSource.setInitialSize(druidInitSize);// 初始化连接数
druidDataSource.setMinIdle(druidMinIdle); // 最小连接数
druidDataSource.setMaxActive(druidMaxActive);// 最大连接数
druidDataSource.setPoolPreparedStatements(true);// 开启缓存preparedStatement
druidDataSource.setUseGlobalDataSourceStat(true);
// 开启Druid提供的3s慢SQL监控
Properties properties = new Properties();
properties.put("druid.stat.mergeSql", true);
properties.put("druid.stat.slowSqlMillis", 3000);
druidDataSource.setConnectProperties(properties);
try {
druidDataSource.setFilters("stat,wall");
druidDataSource.init();
} catch (SQLException e) {
log.error("构建数据库连接池异常,异常原因:{}", e);
throw new RuntimeException(e);
}
DynamicPGDataSource dynamicPGDataSource = new DynamicPGDataSource();
Map<Object, Object> targetDataSources = new HashMap<>();
targetDataSources.put(ConnectInfo.currentPGIP, druidDataSource);
dynamicPGDataSource.setTargetDataSources(targetDataSources);
dynamicPGDataSource.setDefaultTargetDataSource(druidDataSource);
return dynamicPGDataSource;
}
-
类定义
public class DynamicPGDataSource extends AbstractRoutingDataSource {
@Override
protected Object determineCurrentLookupKey() {
return DataSourceContext.getPGDataSource();
}
}public class DataSourceContext {
private static String pgDataSource;public static void setPGDataSource(String ds) { pgDataSource = ds; } public static String getPGDataSource() { return pgDataSource; }
}
-
定义re方法,当监听到数据源IP更改之后,去切换连接到新的数据源,并且关闭老的数据源连接。
public void refreshPGDataSource(String ip) {
if(ConnectInfo.currentPGIP.equals(ip)) {
log.info("currentPGIP equals ip, not operate, ip:{}", ip);
}
DynamicPGDataSource dynamicPGDataSource = ((DynamicPGDataSource)druidDataSource);
Field field = null;
try {
field = AbstractRoutingDataSource.class.getDeclaredField("targetDataSources");
} catch (NoSuchFieldException e) {
e.printStackTrace();
}
field.setAccessible(true);// 获取当前的 targetDataSources Map<Object, Object> currentDataSources = null; try { currentDataSources = (Map<Object, Object>) field.get(dynamicPGDataSource); if(!currentDataSources.containsKey(ip)) { DruidDataSource druidDataSource = DruidDataSourceBuilder.create().build(); String address = String.format("jdbc:postgresql://%s:5432/dsgdb?characterEncoding=utf-8&useSSL=false", ip); druidDataSource.setUrl(address); druidDataSource.setUsername(username); druidDataSource.setPassword(password); druidDataSource.setDriverClassName(driverClassName); druidDataSource.setInitialSize(20);// 初始化连接数 druidDataSource.setMinIdle(10); // 最小连接数 druidDataSource.setMaxActive(100);// 最大连接数 druidDataSource.setPoolPreparedStatements(true);// 开启缓存preparedStatement druidDataSource.setUseGlobalDataSourceStat(true); // 开启Druid提供的3s慢SQL监控 Properties properties = new Properties(); properties.put("druid.stat.mergeSql", true); properties.put("druid.stat.slowSqlMillis", 3000); druidDataSource.setConnectProperties(properties); druidDataSource.setFilters("stat,wall"); currentDataSources.put(ip, druidDataSource); field.set(dynamicPGDataSource, currentDataSources); dynamicPGDataSource.afterPropertiesSet(); } DataSourceContext.setPGDataSource(ip); ConnectInfo.currentPGIP = ip; // 关闭无用连接 Iterator<Map.Entry<Object, Object>> iterator = currentDataSources.entrySet().iterator(); while (iterator.hasNext()) { Map.Entry<Object, Object> entry = iterator.next(); if(!ip.equals(entry.getKey())) { DruidDataSource dataSource = (DruidDataSource)currentDataSources.get(entry.getKey()); dataSource.close(); iterator.remove(); } } } catch (IllegalAccessException | SQLException e) { e.printStackTrace(); } }