如果我在Java配置中覆盖了bean定义，将会发生什么? [英] what will happen if I override a bean definition in java config?

问题描述

使用Spring Data Mongodb开发时，我想在MongoDB配置中进行一些自定义. 通常，我将扩展AbstractMongoConfiguration，并实现抽象方法.当前， AbstractMongoConfiguration 类具有以下内容:

When developing with Spring Data Mongodb, I want to do some customization in my MongoDB configuraion. General, I will extends the AbstractMongoConfiguration, and implement the abstract methods. currently, the AbstractMongoConfiguration class has the following:

@Configuration
public abstract AbstractConfiguration extends MongoConfigurationSupport {
    public abstract MongoClient mongoClient();

    @Bean
    public MongoTemplate mongoTemplate() throws Exception {
          return new MongoTemplate(mongoDbFactor(), mappingMongoConverter());

    ....   
}

扩展此类时，我想自定义bean MongoTemplate ，所以我想重写 mongoTemplate 方法，这行得通吗?

When extending this class, I want to customize the bean MongoTemplate, So I want to override the mongoTemplate method, does this work?

@Configuration
public MongoConfiguration extends AbstractConfiguration {
    public MongoClient mongoClient(){
        ....
    }

    @Override
    @Bean
    public MongoTemplate mongoTemplate() throws Exception {
          MongoTemplate template = super.mongoTemplate();
          template.setWriteResultChecking(WriteResultChecking.EXCEPTION);
    }

    ....   
}

推荐答案

最近有一个非常相似的问题.

Had an extremely similar issue recently.

有2种情况:

@Configuration
public MongoConfiguration extends AbstractConfiguration {
    public MongoClient mongoClient(){
        ....
    }

    @Override
    @Bean
    public MongoTemplate mongoTemplate() throws Exception {
          MongoTemplate template = super.mongoTemplate();
          template.setWriteResultChecking(WriteResultChecking.EXCEPTION);
    }

    ....   
}

在这种情况下，将使用覆盖的定义而不是父定义来注册Bean.另外，只能注册1个豆.

In this case, the bean will be registered by using your overridden definition and not your parent definition. Also, only 1 bean will be registered.

@Configuration
public MongoConfiguration extends AbstractConfiguration {
    public MongoClient mongoClient(){
        ....
    }

    @Override
    @Bean(name="myBean")
    public MongoTemplate mongoTemplate() throws Exception {
          MongoTemplate template = super.mongoTemplate();
          template.setWriteResultChecking(WriteResultChecking.EXCEPTION);
    }

    ....   
}

在这种情况下，将创建 2个豆(mongoTemplate和myBean).但是，对于两个bean的创建，都将使用您覆盖的实现.

In this case, 2 beans(mongoTemplate and myBean) will be created. But, for the creation of both the beans, your overridden implementation will be used.

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