Spring 启动 java 配置不起作用

Question

I'm not sure what's going on here. I've been building spring apps for years and years and feel like I've just missed something.

I have a spring boot app created through the spring initializer. I created a configuration class like this.

@Configuration
public class WfwwebConfiguration {


    @Bean
    public WebClient webClientBean() {
        return new WebClient(MpesaPaymentService.MPESA_HOST, MpesaPaymentService.MPESA_PORT);
    }
}

The goal, of course, here is to create my WebClient class myself. The problem is that spring kept running the no-argument constructor on it, which was trying to go to localhost.

So I deleted that constructor and now my spring boot app won't start because WebClient doesn't have a no-arg constructor.

So what did I miss? I have

@SpringBootApplication
public class WfwwebApplication {
    public static void main(String[] args) {
        SpringApplication.run(WfwwebApplication.class, args);
    }
}

Which is supposed to turn on auto configuration and all the research I've done says it will now pick up the configuration class automatically.

I double checked my @Configuration to make sure it wasn't loading it from another library. ;)

Ideas?

Answer 1

Please consider the following working minimal example that will print out "Hello, StackOverflow" on start-up using a @Configuration producing an object of a class with no-arg constructor.

Application.java

package org.example;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class Application {

    public static void main(String[] args) {
        SpringApplication.run(Application.class, args);
    }
}

ApplicationConfiguration.java

package org.example;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

@Configuration
public class ApplicationConfiguration {

    @Bean
    public Greeter greeter() {
        return new Greeter("StackOverflow");
    }
}

AppStartupRunner.java

package org.example;

import org.springframework.boot.ApplicationArguments;
import org.springframework.boot.ApplicationRunner;
import org.springframework.stereotype.Component;

@Component
public class AppStartupRunner implements ApplicationRunner {

    private final Greeter greeter;

    public AppStartupRunner(Greeter greeter) {
        this.greeter = greeter;
    }

    @Override
    public void run(ApplicationArguments args) {
        this.greeter.greet();
    }
}

Greeter.java

package org.example;

public class Greeter {

    private final String name;

    public Greeter(String name) {
        this.name = name;
    }

    public void greet() {
        System.out.println("Hello, " + this.name);
    }
}

Answer 2

I was running inside the intelliJ idea environment when I found this issue. After trying many things, I tried turning debug on in the run configuration and there was nothing helpful in the messages generated.

When I turned the setting back off and re-ran the app it started working perfectly on its own.

Please post a comment if this helps someone else. I'm curious if this was it.