无法读取配置属性

Question

我正在尝试使用ConfiguartionProperties从application.prop文件读取属性。但是我收到了NullPointerException，因为在启动bean时，无法从application.prop文件中正确读取属性。

    @Configuration
    @ConfigurationProperties(prefix = "httpool")
    public class ClientHttpPoolConfig {

        private Integer maxPerRoute;
        private Integer maxTotal;
        private Integer connectionRequestTimeout;
        private Integer connectTimeout;
        private Integer socketTimeout;

        @Bean
        public PoolingHttpClientConnectionManager poolingHttpClntConnMger() {
            PoolingHttpClientConnectionManager result = new PoolingHttpClientConnectionManager();
            result.setDefaultMaxPerRoute(maxPerRoute);  // maxPerRoute is null.
            result.setMaxTotal(maxTotal);
            return result;
        }
}

Answer 1

我已尽可能地简化了，所以我使用的是非常简单的bean：

StringWrapper

package betlista.springTests.beanInConfiguration;

/** Represents a very simple Bean */
public class StringWrapper {

    private String name;

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

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

}

配置类也没有什么特别的...

配置

package betlista.springTests.beanInConfiguration;

import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.stereotype.Component;

@Component
@ConfigurationProperties
public class Config {

    String name;

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    @Bean
    public StringWrapper getStringWrapper() {
        return new StringWrapper(name);
    }

}

最后申请

package betlista.springTests.beanInConfiguration;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.CommandLineRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class SpringBootConsoleApplication implements CommandLineRunner {

    private static Logger LOG = LoggerFactory.getLogger(SpringBootConsoleApplication.class);

    @Autowired
    StringWrapper stringWrapper;

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

    @Override
    public void run(String... args) {
        LOG.info("stringWrapper.name: {}", stringWrapper.getName());
    }

}

只是为了完整性

pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>betlista</groupId>
    <artifactId>springTests-beanInConfiguration</artifactId>
    <version>1.0</version>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.2.5.RELEASE</version>
    </parent>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
        </dependency>

        <!-- https://mvnrepository.com/artifact/org.springframework.boot/spring-boot-starter-test -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <version>2.2.5.RELEASE</version>
            <scope>test</scope>
        </dependency>

    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

前缀

属性文件中的@ConfigurationProperties("my")和my.name=Betlista几乎可以使用。

全部在GitHub中可用：https://github.com/Betlista/SpringTests/tree/master/BeanInConfiguration

Answer 2

在application.properties文件中，参数应如下所示：

httpool.max-per-route=//here  your Integer value
httpool.max-total=//here  your Integer value
httpool.connection-requestTimeout=//here  your Integer value
httpool.connect-timeout=//here  your Integer value
httpool.socket-timeout=//here  your Integer value

编辑： 并且您必须将此注释写到您的Main class

@EnableConfigurationProperties({
        ClientHttpPoolConfig.class
})