簡單的說，程式設計師可以使用同一個JNDI介面來查詢以下內容

• 尋找應用程式伺服器提供的資源，例如資料來源
• 搜尋 LDAP 條目
• 查找 DNS 記錄

簡單介紹就到這裡

程式碼

應用程式伺服器的資源放置在「java:comp/env」前綴下。假設資料來源位於

java:/comp/env/jdbc/db1

取得此資料來源

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");

或您可以透過提供完整路徑直接取得實例

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

Spring引導集成

只需在 application.properties
中新增一行

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

相關bean由org.springframework.boot.autoconfigure.jdbc.JndiDataSourceAutoConfiguration創建

@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);
            }
        }
    }

}