抽象类对象的子类在使用自动连线时为 null

Question

我有这些类。 当我调试时，我看到 spring 在构造函数中创建服务对象并在两个类中调用构造函数，但是当我想使用这些字段时，它们是空的。怎么了？！(类型1处理器、类型2处理器和类型3处理器为空(

import com.vali.ReactiveSocketServer.service.ReceivedDataService;
import org.springframework.stereotype.Component;
public abstract class Processor {
public ReceivedDataService receivedDataService;
public Processor(ReceivedDataService receivedDataService) {
    this.receivedDataService = receivedDataService;
}
public abstract void readStream(String stream);
}

这是它的子类

import com.vali.ReactiveSocketServer.model.ReceivedData;
import com.vali.ReactiveSocketServer.service.ReceivedDataService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
@Component
public class Type1Processor extends Processor {

@Autowired
public Type1Processor(ReceivedDataService receivedDataService) {
    super(receivedDataService);
}
@Override
public void readStream(String stream) {
    System.out.println("readStream "+ getClass().getSimpleName() + "-" + stream);
    receivedDataService.add(new ReceivedData(stream.getBytes()));
}
}

这是它的用法：

import com.vali.ReactiveSocketServer.processor.Processor;
import com.vali.ReactiveSocketServer.processor.Type1Processor;
import com.vali.ReactiveSocketServer.processor.Type2Processor;
import com.vali.ReactiveSocketServer.processor.Type3Processor;
import com.vali.ReactiveSocketServer.receivers.AppServer;
import com.vali.ReactiveSocketServer.socket.ClientHandler;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import java.util.HashMap;
import java.util.Map;
@SpringBootApplication
public class ReactiveSocketServerApplication {
private AppServer appServer;
@Autowired
Type1Processor type1Processor;
@Autowired
Type2Processor type2Processor;
@Autowired
Type3Processor type3Processor;
public static void main(String[] args) {
    SpringApplication.run(ReactiveSocketServerApplication.class, args);
    ReactiveSocketServerApplication reactiveSocketServerApplication = new ReactiveSocketServerApplication();
    reactiveSocketServerApplication.Start();
}

public void Start(){
    appServer = AppServer.getInstance();
    Map<Integer, Processor> processorMap = new HashMap<>();
    processorMap.put(7001, type1Processor);
    processorMap.put(7002, type2Processor);
    processorMap.put(7003, type3Processor);
    appServer.initialize(processorMap);
    new ClientHandler(7001, 1000);
    new ClientHandler(7002, 5000);
}
}

Answer 1

您正在自己实例化ReactiveSocketServerApplication。

因此，Spring 无法注入@Autowired注释的 bean，因为实例是在它的生命周期之外创建的。

完全删除它：

ReactiveSocketServerApplication reactiveSocketServerApplication = new ReactiveSocketServerApplication();
reactiveSocketServerApplication.Start();

并用@PostConstruct注释您的Start()：

@PostConstruct
public void Start() { ... }

Answer 2

您在抽象类ReceivedDataService中缺少@Component。

这意味着当您使用以下方法创建子分支时：

@Autowired
public Type1Processor(ReceivedDataService receivedDataService) {
   super(receivedDataService);
}

无法注入接收数据服务并获取默认值(null(