RowMapper中的Autowire Objectmapper [英] Autowire Objectmapper in RowMapper

问题描述

我发现答案说可以在内部自动接线行映射器

I found answers say it possible to autowire inside rowmapper,

如果您想让ScoreMapper实例具有一个Spring Bean注入ScoreCreator scoreCreator，那么ScoreMapper实例本身必须是一个Spring Bean，即.由Spring创建和管理

If you want ScoreMapper instances to have ScoreCreator scoreCreator be injected with a Spring bean, the ScoreMapper instance itself must be a Spring bean, ie. created and managed by Spring

或通过添加 @Component

Or by adding @Component

您可以将PersonUtility类定义为spring bean，并在该类上添加@component.

You can define PersonUtility class as spring bean adding @component over the class.

但是当前RowMapper是用jdbcTemplate.query中的new实例化的:

But currently RowMapper is instantiated with new in jdbcTemplate.query:

jdbcTemplate.query(SQL, new Object[] {}, new MyRowMapper())

而且我无法自动将Spring托管的ObjectMapper接线

And I can't autowire Spring managed ObjectMapper inside

public class MyRowMapper implements RowMapper<Map<Integer, Type>> {

   @Autowired
   @Qualifier("myObjectMapper")
   ObjectMapper objectMapper;

我应该如何重构当前代码来管理bean行映射器?

How should I refactor current code to manage bean row mapper?

推荐答案

RowMapper是线程安全的类.这意味着它的单个实例可以在多个线程之间共享.因此，这意味着，您可以将其设为单例类，并让spring处理其生命周期(使用@Component之类的批注之一).而且，无论您要使用它的实例是什么，都只需自动装配/注入现有实例，而不是每次都实例化(new)

RowMapper is a thread safe class. That means, it's single instance can be shared amongst multiple threads. So, that means, you can let it be a singleton class and let spring handle it's lifecycle (Using one of those annotation like @Component). And wherever you want to use it's instance, just autowire/inject existing instance rather than instantiating it every time (new)

@Component
public class MyRowMapper implements RowMapper<Map<Integer, Type>> {

   @Autowired
   @Qualifier("myObjectMapper")
   ObjectMapper objectMapper;

然后

class ASingletonClass(){
  @Autowired MyRowMapper myRowMapper;

  public MyRowMapper myAweSomeMethod(){
    return jdbcTemplate.query(SQL, new Object[] {}, myRowMapper)
  }
}

请参考答案.在相似的行中

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