Question

java.lang.NullPointerException自动装配石英中使用的类

切入点是：

public class AppContainer {
    public static void main(String[] args) {
        ApplicationContext c1 = new ClassPathXmlApplicationContext("rabbit-listener-context.xml");
    }
}

rabbit-listener-context.xml是：

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:c="http://www.springframework.org/schema/c"
       xmlns:p="http://www.springframework.org/schema/p"
       xmlns:task="http://www.springframework.org/schema/task"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
       xmlns:rabbit="http://www.springframework.org/schema/rabbit"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
       http://www.springframework.org/schema/beans/spring-beans-3.1.xsd
       http://www.springframework.org/schema/task
       http://www.springframework.org/schema/task/spring-task-3.2.xsd
       http://www.springframework.org/schema/rabbit
       http://www.springframework.org/schema/rabbit/spring-rabbit-1.0.xsd
       http://www.springframework.org/schema/context
       http://www.springframework.org/schema/context/spring-context-2.5.xsd">

   <context:annotation-config />
    <bean id="placeholderConfig"
          class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
        <property name="locations">
            <list>
                <value>app.conf</value>
            </list>
        </property>
    </bean>

    <import resource="dataSources.xml" />

</beans>

dataSources.xml是：

<?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:jdbc="http://www.springframework.org/schema/jdbc" 
       xmlns:context="http://www.springframework.org/schema/context"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
       http://www.springframework.org/schema/beans/spring-beans-3.1.xsd
       http://www.springframework.org/schema/jdbc 
       http://www.springframework.org/schema/jdbc/spring-jdbc-3.2.xsd
       http://www.springframework.org/schema/context
       http://www.springframework.org/schema/context/spring-context-2.5.xsd">
    <context:annotation-config />
    <import resource="properties.xml"/>

    <bean id="dataSource"  class="org.springframework.jdbc.datasource.DriverManagerDataSource">
        <property name="driverClassName" value="org.postgresql.Driver"/>
        <property name="url" value="jdbc:postgresql://${db.host}/example"/>
        <property name="username" value="${db.userName}"/>
        <property name="password" value="${db.password}"/>
    </bean>


    <bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate" >
        <constructor-arg type="javax.sql.DataSource"><ref bean="dataSource"></ref></constructor-arg>
    </bean>
</beans>

然后要连线的课程是：

public class ConnectorScheduler implements Job {

    final private String sqlQuery = ...";
    private JdbcTemplate jdbcTemplate;

    @Autowired(required = true) 
    public void setJdbcTemplate(JdbcTemplate jdbcTemplate) {
        this.jdbcTemplate = jdbcTemplate;
    }
    private AmqpTemplate rabbitMQTemplate;

    @Autowired(required = true) 
    public void setAmqpTemplate(AmqpTemplate rabbitMQTemplate) {
        this.rabbitMQTemplate = rabbitMQTemplate;
    }

    private String queueName;

    public void execute(JobExecutionContext context) {
     //   SpringBeanAutowiringSupport.processInjectionBasedOnCurrentContext(this);
        Long connectorID = context.getJobDetail().getJobDataMap().getLong("ConnectorID");
           System.out.println("jdbc templaet is "+jdbcTemplate);
        SchedulerBean schedulerBean= jdbcTemplate.query(sqlQuery,new Object[] {connectorID}, new SchedulerMapper()).iterator().next();

...

但它出错了，这意味着jdbcTemplate没有连线。

java.lang.NullPointerException

Answer 1

只有在需要自动装配值的bean由Spring容器管理时，Spring依赖注入才有效。您的上下文定义不包含ConnectorScheduler的bean定义，所以我假设您正在尝试手动创建它，这会导致注入问题。

添加适当的定义可以解决您的问题。

<bean id="connectorScheduler" class="org.your.package.ConnectorScheduler" />

春天自动装配：不起作用

1 个答案: