我现在正在学习春天。这是我的示例代码。我正在使用 jersey、spring、hibernate 和 mysql 作为 REST 服务。
CustomerServiceImpl.java这是 REST 端点（部分代码）
package com.samples.service.impl;
@Path("customers")
public class CustomerServiceImpl implements CustomerService {
private static Logger logger = Logger.getLogger(CustomerServiceImpl.class);
@Autowired
CustomerBO customerBO;
here is CustomerBOImpl.java（部分代码）
package com.samples.BO.impl;
@Component
public class CustomerBOImpl implements CustomerBO {
@Autowired
CustomerDAO customerDAO;
@Autowired
CustomerAdapter customerAdapter;
CustomerDAOImpl.类
包 com.samples.DAO.impl；
@Repository
public class CustomerDAOImpl implements CustomerDAO {
this is 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:context="http://www.springframework.org/schema/context"
xmlns:tx="http://www.springframework.org/schema/tx"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context-3.0.xsd
http://www.springframework.org/schema/tx
http://www.springframework.org/schema/tx/spring-tx-3.1.xsd">
<context:property-placeholder location="classpath*:database.properties"/>
<context:component-scan base-package="com.samples"/>
<context:annotation-config />
</beans>
这是我收到的前几行异常。
http-bio-8090-exec-1] [class: CustomerServiceImpl] INFO - list all customers
[http-bio-8090-exec-1] [class: CustomerServiceImpl] INFO - customerBO is null
May 08, 2014 10:55:29 AM com.sun.jersey.spi.container.ContainerResponse mapMappableContainerException
SEVERE: The RuntimeException could not be mapped to a response, re-throwing to the HTTP container
java.lang.NullPointerException
at com.samples.service.impl.CustomerServiceImpl.getAllCustomers(CustomerServiceImpl.java:40)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at com.sun.jersey.spi.container.JavaMethodInvokerFactory$1.invoke(JavaMethodInvokerFactory.java:60)
at com.sun.jersey.server.impl.model.method.dispatch.AbstractResourceMethodDispatchProvider$TypeOutInvo
这是 web.xml
<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<web-app xmlns="http://java.sun.com/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
version="2.5">
<display-name>Employee Service</display-name>
<context-param>
<param-name>contextConfigLocation</param-name>
<param-value>
classpath*:applicationContext.xml
</param-value>
</context-param>
<context-param>
<param-name>initializeContextOnStartup</param-name>
<param-value>true</param-value>
</context-param>
<listener>
<listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
</listener>
<servlet>
<servlet-name>jersey-serlvet</servlet-name>
<servlet-class>com.sun.jersey.spi.container.servlet.ServletContainer</servlet-class>
<init-param>
<param-name>com.sun.jersey.config.property.packages</param-name>
<param-value>com.samples.service</param-value>
</init-param>
<init-param>
<param-name>com.sun.jersey.api.json.POJOMappingFeature</param-name>
<param-value>true</param-value>
</init-param>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>jersey-serlvet</servlet-name>
<url-pattern>/*</url-pattern>
</servlet-mapping>
</web-app>
所以如果我理解这是如何正确工作的，我configuring xml通过提供我想要运行自动扫描的包来自动扫描我的组件。对于我想要自动装配的对象。在CustomerServiceImpl类，我使用@autowiredcustomerBO应该由 CustomerBOImpl.class 定义上的 @Component 注释扫描的对象。您能帮忙解释一下为什么我的自动扫描没有拾取自动连接的 customerBO 对象吗？
谢谢。
