简单的说，程序员可以使用同一个JNDI接口来查询以下内容

• 查找应用服务器提供的资源，例如数据源
• 搜索 LDAP 条目
• 查找 DNS 记录

简单介绍就到这里

代码

应用程序服务器的资源放置在“java:comp/env”前缀下。假设数据源位于

java:/comp/env/jdbc/db1

获取该数据源

javax.naming.Context initialContext = new javax.naming.InitialContext();
javax.naming.Context subContext = (javax.naming.Context) initialContext.lookup("java:comp/env");
DataSource dataSource = (DataSource) subContext.lookup("jdbc/db1");

或者您可以通过提供完整路径直接获取实例

javax.naming.Context initialContext = new javax.naming.InitialContext();
DataSource dataSource = (DataSource) initialContext.lookup("java:comp/env/jdbc/db1");

Spring引导集成

只需在 application.properties
中添加一行

spring.datasource.jndi-name=java:/comp/env/jdbc/db1

相关bean由org.springframework.boot.autoconfigure.jdbc.JndiDataSourceAutoConfiguration创建

@Configuration(proxyBeanMethods = false)
@AutoConfigureBefore({ XADataSourceAutoConfiguration.class, DataSourceAutoConfiguration.class })
@ConditionalOnClass({ DataSource.class, EmbeddedDatabaseType.class })
@ConditionalOnProperty(prefix = "spring.datasource", name = "jndi-name")
@EnableConfigurationProperties(DataSourceProperties.class)
public class JndiDataSourceAutoConfiguration {

    @Bean(destroyMethod = "")
    @ConditionalOnMissingBean
    public DataSource dataSource(DataSourceProperties properties, ApplicationContext context) {
        JndiDataSourceLookup dataSourceLookup = new JndiDataSourceLookup();
        DataSource dataSource = dataSourceLookup.getDataSource(properties.getJndiName());
        excludeMBeanIfNecessary(dataSource, "dataSource", context);
        return dataSource;
    }

    private void excludeMBeanIfNecessary(Object candidate, String beanName, ApplicationContext context) {
        for (MBeanExporter mbeanExporter : context.getBeansOfType(MBeanExporter.class).values()) {
            if (JmxUtils.isMBean(candidate.getClass())) {
                mbeanExporter.addExcludedBean(beanName);
            }
        }
    }

}