Question

我正在使用配置文件创建一个bean。 bean在服务器启动期间被初始化我在其中有一个调试点并且它被触发。当我的restApi调用handler方法时，它会抛出NPE，其中coinResponse为null。请让我知道我在这里做错了什么。

的ConfigurationFile

package com.foo.service.handler;
@Configuration
@ComponentScan("com.foo.service")
public class CacheConfiguration {
    @Bean
    public CoinResponse getCoinResponse() {
        return new CoinResponse();
    }
}

handlerFile

package com.foo.service.handler;
public class DetailsHandler {

    @Inject
    CoinResponse getCoinResponse;
    public List<CoinResponse> getCoinDetails() {
        System.out.println(getCoinResponse.getClass());
    }
}

的web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
    xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
    id="WebApp_ID" version="2.5">
    <display-name>foosvc</display-name>
    <context-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>/WEB-INF/applicationContext.xml</param-value>
    </context-param>
    <listener>
        <listener-class>
            org.springframework.web.context.ContextLoaderListener
        </listener-class>
    </listener>
    <context-param>
        <param-name>contextClass</param-name>
        <param-value>org.springframework.web.context.support.XmlWebApplicationContext</param-value>
    </context-param>
    <servlet>
        <servlet-name>jersey-serlvet</servlet-name>
        <servlet-class>
            org.glassfish.jersey.servlet.ServletContainer
        </servlet-class>
        <init-param>
            <param-name>jersey.config.server.provider.packages</param-name>
            <param-value>com.foo.service</param-value>
        </init-param>
        <load-on-startup>1</load-on-startup>
    </servlet>

    <servlet-mapping>
        <servlet-name>jersey-serlvet</servlet-name>
        <url-pattern>/webapi/*</url-pattern>
    </servlet-mapping>

</web-app>

的applicationContext.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:c="http://www.springframework.org/schema/c" xmlns:p="http://www.springframework.org/schema/p" xmlns:context="http://www.springframework.org/schema/context" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.1.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.1.xsd">
    <context:annotation-config />

    <context:component-scan base-package="com.fomo.service" />

</beans>

Answer 1

可能在Spring中没有定义DetailsHandler。

依赖注入（@Inject）只能在Spring使用的类中发生。请尝试在DetailsHandler类中创建一个no-ops构造函数，并在那里放置一个断点。

根据您的弹簧配置，您应该使用@Component或其中一个刻板印象（例如@Controller）对其进行注释。

Bean被初始化，但是注入会引发npe

1 个答案: