带有 spring boot @component 注释类的构建器模式

Question

I am a newbie with spring. I am trying to build a URL using the properties from application.properties file in a spring boot project using the org.springframework.beans.factory.annotation.Value annotation.

The class ElasticConfiguration picks the properties from the property file. But, there can be scenarios where the port and protocol are optional.

@Component
public class ElasticConfiguration {

    @Value("${elasticsearch.hostname}")
    String hostname;
    @Value("${elasticsearch.portnumber}")
    Integer portnumber;
    @Value("${elasticsearch.protocol}")
    String protocol;

    public String getHostname() {
        return hostname;
    }

    public void setHostname(String hostname) {
        this.hostname = hostname;
    }

    public Integer getPortnumber() {
        return portnumber;
    }

    public void setPortnumber(Integer portnumber) {
        this.portnumber = portnumber;
    }

    public String getProtocol() {
        return protocol;
    }

    public void setProtocol(String protocol) {
        this.protocol = protocol;
    }

}

To solve it i am using a builder class which builds the URL object basing on the available properties

public class URL {

    private final String _hostname;
    private final String _portnumber;
    private final String _protocol;

    private URL(URLBuilder builder){
        this._hostname = builder._hostname;
        this._portnumber = builder._portnumber;
        this._protocol = builder._protocol;
    }

    public String get_hostname() {
        return _hostname;
    }

    public String get_portnumber() {
        return _portnumber;
    }

    public String get_protocol() {
        return _protocol;
    }

    public static class URLBuilder {
        private final String _hostname;
        private String _portnumber;
        private String _protocol;

        public URLBuilder(String hostname){
            this._hostname = hostname;
        }

        public URLBuilder portNumber(String value) {
            this._portnumber = value;
            return this;
        }

        public URLBuilder protocol(String value) {
            this._protocol = value;
            return this;
        }

        public URL build() {
            return new URL(this);
        }
    }

    @Override
    public String toString() {
        return "URL [_hostname=" + _hostname + ", _portnumber=" + _portnumber + ", _protocol=" + _protocol + "]";
    }

}

I would like to use a builder approach in the spring boot @component annotated class.

1. Is this the right way to do in spring boot?
2. Is spring boot providing any such API's already to simulate the builder pattern?
3. How to integrate above two classes to achieve what i want?

Answer 1

使用 lombok.jar，它会有@builder 来解决你的问题