如何在Spring Boot中以编程方式创建bean？
我有一个应用程序，它在application.properties中列出了许多数据源设置。我有一个加载这些设置的@ConfigurationProperties类。现在，我想从这个ConfigurationProperties类中获取值，并使用它们动态创建DataSource bean。我尝试过使用@PostConstruct和实现BeanFactoryPostProcessor。然而，对于BeanFactoryPostProcessor，处理似乎发生在早期--在填充ConfigurationProperties类之前。如何使用Spring Boot动态读取属性和创建DataSource beans？
下面是我的application.properties的样子：
ds.clients[0]=client1|jdbc:db2://server/client1
ds.clients[1]=client2,client3|jdbc:db2://server/client2
ds.clients[2]=client4|jdbc:db2://server/client4
ds.clients[3]=client5|jdbc:db2://server/client5还有我的ConfigurationProperties类：
@Component
@ConfigurationProperties(prefix = "ds")
public class DataSourceSettings {
public static Map<String, String> CLIENT_DATASOURCES = new LinkedHashMap<>();
private List<String> clients = new ArrayList<>();
public List<String> getClients() {
return clients;
}
public void setClients(List<String> clients) {
this.clients = clients;
}
@PostConstruct
public void configure() {
for (String client : clients) {
// extract client name
String[] parts = client.split("\\|");
String clientName = parts[0];
String url = parts[1];
// client to datasource mapping
String dsName = url.substring(url.lastIndexOf("/") + 1);
if (clientName.contains(",")) {
// multiple clients with same datasource
String[] clientList = clientName.split(",");
for (String c : clientList) {
CLIENT_DATASOURCES.put(c, dsName);
}
} else {
CLIENT_DATASOURCES.put(clientName, dsName);
}
}
}在此@PostConstruct方法的末尾，我想使用这些设置创建一个BasicDataSource并将其添加到ApplicationContext中。但是，如果我尝试通过实现BeanFactoryPostProcessor和postProcessBeanFactory来完成此操作，则clients属性为null，正如我用@PostConstruct填充的CLIENT_DATASOURCES一样。
@Override
public void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) throws BeansException {
System.out.println("clients: " + CLIENT_DATASOURCES);
}使用Spring Boot动态创建数据源的最佳方式是什么？
Stack Overflow用户
发布于 2014-08-06 20:47:13
创建bean并让Spring Boot向其中注入值如何？
就像这样
@Bean
@ConfigurationProperties("ds.client1")
public DataSource dataSourceClient1() {
DataSourceBuilder.create().build();
}
@Bean
@ConfigurationProperties("ds.client2")
public DataSource dataSourceClient2() {
DataSourceBuilder.create().build();
}然后，ds.client1名称空间中的任何设置都属于第一个数据源(即ds.client1.password是该DataSource的数据源密码)。
但也许你不知道你会有多少数据源？这变得越来越复杂，特别是当您需要在其他对象中注入这些动态数据源时。如果您只需要按名称查找它们，您可以自己将它们注册为单例。下面是一个有效的示例
@ConfigurationProperties(prefix = "ds")
public class DataSourceSettings implements BeanFactoryAware {
private List<String> clients = new ArrayList<>();
private BeanFactory beanFactory;
public List<String> getClients() {
return clients;
}
public void setClients(List<String> clients) {
this.clients = clients;
}
@Override
public void setBeanFactory(BeanFactory beanFactory) {
this.beanFactory = beanFactory;
}
@PostConstruct
public void configure() {
Map<String, String> clientDataSources = new HashMap<String, String>();
for (String client : clients) {
// extract client name
String[] parts = client.split("\\|");
String clientName = parts[0];
String url = parts[1];
// client to datasource mapping
String dsName = url.substring(url.lastIndexOf("/") + 1);
if (clientName.contains(",")) {
// multiple clients with same datasource
String[] clientList = clientName.split(",");
for (String c : clientList) {
clientDataSources.put(c, url);
}
}
else {
clientDataSources.put(clientName, url);
}
}
Assert.state(beanFactory instanceof ConfigurableBeanFactory, "wrong bean factory type");
ConfigurableBeanFactory configurableBeanFactory = (ConfigurableBeanFactory) beanFactory;
for (Map.Entry<String, String> entry : clientDataSources.entrySet()) {
DataSource dataSource = createDataSource(entry.getValue());
configurableBeanFactory.registerSingleton(entry.getKey(), dataSource);
}
}
private DataSource createDataSource(String url) {
return DataSourceBuilder.create().url(url).build();
}
}请注意，这些bean是只能通过bean名称查找获得的。如果这对你有帮助，请告诉我。
https://stackoverflow.com/questions/25160221
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